/*
 *  Single source autogenerated distributable for Duktape 2.5.0.
 *
 *  Git commit 6001888049cb42656f8649db020e804bcdeca6a7 (v2.5.0).
 *  Git branch master.
 *
 *  See Duktape AUTHORS.rst and LICENSE.txt for copyright and
 *  licensing information.
 */

/* LICENSE.txt */
/*
*  ===============
*  Duktape license
*  ===============
*
*  (http://opensource.org/licenses/MIT)
*
*  Copyright (c) 2013-2019 by Duktape authors (see AUTHORS.rst)
*
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*
*  The above copyright notice and this permission notice shall be included in
*  all copies or substantial portions of the Software.
*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

/* AUTHORS.rst */
/*
*  ===============
*  Duktape authors
*  ===============
*
*  Copyright
*  =========
*
*  Duktape copyrights are held by its authors.  Each author has a copyright
*  to their contribution, and agrees to irrevocably license the contribution
*  under the Duktape ``LICENSE.txt``.
*
*  Authors
*  =======
*
*  Please include an e-mail address, a link to your GitHub profile, or something
*  similar to allow your contribution to be identified accurately.
*
*  The following people have contributed code, website contents, or Wiki contents,
*  and agreed to irrevocably license their contributions under the Duktape
*  ``LICENSE.txt`` (in order of appearance):
*
*  * Sami Vaarala <sami.vaarala@iki.fi>
*  * Niki Dobrev
*  * Andreas \u00d6man <andreas@lonelycoder.com>
*  * L\u00e1szl\u00f3 Lang\u00f3 <llango.u-szeged@partner.samsung.com>
*  * Legimet <legimet.calc@gmail.com>
*  * Karl Skomski <karl@skomski.com>
*  * Bruce Pascoe <fatcerberus1@gmail.com>
*  * Ren\u00e9 Hollander <rene@rene8888.at>
*  * Julien Hamaide (https://github.com/crazyjul)
*  * Sebastian G\u00f6tte (https://github.com/jaseg)
*  * Tomasz Magulski (https://github.com/magul)
*  * \D. Bohdan (https://github.com/dbohdan)
*  * Ond\u0159ej Jirman (https://github.com/megous)
*  * Sa\u00fal Ibarra Corretg\u00e9 <saghul@gmail.com>
*  * Jeremy HU <huxingyi@msn.com>
*  * Ole Andr\u00e9 Vadla Ravn\u00e5s (https://github.com/oleavr)
*  * Harold Brenes (https://github.com/harold-b)
*  * Oliver Crow (https://github.com/ocrow)
*  * Jakub Ch\u0142api\u0144ski (https://github.com/jchlapinski)
*  * Brett Vickers (https://github.com/beevik)
*  * Dominik Okwieka (https://github.com/okitec)
*  * Remko Tron\u00e7on (https://el-tramo.be)
*  * Romero Malaquias (rbsm@ic.ufal.br)
*  * Michael Drake <michael.drake@codethink.co.uk>
*  * Steven Don (https://github.com/shdon)
*  * Simon Stone (https://github.com/sstone1)
*  * \J. McC. (https://github.com/jmhmccr)
*  * Jakub Nowakowski (https://github.com/jimvonmoon)
*  * Tommy Nguyen (https://github.com/tn0502)
*  * Fabrice Fontaine (https://github.com/ffontaine)
*  * Christopher Hiller (https://github.com/boneskull)
*  * Gonzalo Diethelm (https://github.com/gonzus)
*  * Michal Kasperek (https://github.com/michalkas)
*  * Andrew Janke (https://github.com/apjanke)
*  * Steve Fan (https://github.com/stevefan1999)
*  * Edward Betts (https://github.com/edwardbetts)
*  * Ozhan Duz (https://github.com/webfolderio)
*  * Akos Kiss (https://github.com/akosthekiss)
*  * TheBrokenRail (https://github.com/TheBrokenRail)
*  * Jesse Doyle (https://github.com/jessedoyle)
*  * Gero Kuehn (https://github.com/dc6jgk)
*  * James Swift (https://github.com/phraemer)
*  * Luis de Bethencourt (https://github.com/luisbg)
*  * Ian Whyman (https://github.com/v00d00)
*  * Rick Sayre (https://github.com/whorfin)
*
*  Other contributions
*  ===================
*
*  The following people have contributed something other than code (e.g. reported
*  bugs, provided ideas, etc; roughly in order of appearance):
*
*  * Greg Burns
*  * Anthony Rabine
*  * Carlos Costa
*  * Aur\u00e9lien Bouilland
*  * Preet Desai (Pris Matic)
*  * judofyr (http://www.reddit.com/user/judofyr)
*  * Jason Woofenden
*  * Micha\u0142 Przyby\u015b
*  * Anthony Howe
*  * Conrad Pankoff
*  * Jim Schimpf
*  * Rajaran Gaunker (https://github.com/zimbabao)
*  * Andreas \u00d6man
*  * Doug Sanden
*  * Josh Engebretson (https://github.com/JoshEngebretson)
*  * Remo Eichenberger (https://github.com/remoe)
*  * Mamod Mehyar (https://github.com/mamod)
*  * David Demelier (https://github.com/markand)
*  * Tim Caswell (https://github.com/creationix)
*  * Mitchell Blank Jr (https://github.com/mitchblank)
*  * https://github.com/yushli
*  * Seo Sanghyeon (https://github.com/sanxiyn)
*  * Han ChoongWoo (https://github.com/tunz)
*  * Joshua Peek (https://github.com/josh)
*  * Bruce E. Pascoe (https://github.com/fatcerberus)
*  * https://github.com/Kelledin
*  * https://github.com/sstruchtrup
*  * Michael Drake (https://github.com/tlsa)
*  * https://github.com/chris-y
*  * Laurent Zubiaur (https://github.com/lzubiaur)
*  * Neil Kolban (https://github.com/nkolban)
*  * Wilhelm Wanecek (https://github.com/wanecek)
*  * Andrew Janke (https://github.com/apjanke)
*  * Unamer (https://github.com/unamer)
*  * Karl Dahlke (eklhad@gmail.com)
*
*  If you are accidentally missing from this list, send me an e-mail
*  (``sami.vaarala@iki.fi``) and I'll fix the omission.
*/

/*
 *  Replacements for missing platform functions.
 *
 *  Unlike the originals, fpclassify() and signbit() replacements don't
 *  work on any floating point types, only doubles.  The C typing here
 *  mimics the standard prototypes.
 */

/* #include duk_internal.h */
/*
 *  Top-level include file to be used for all (internal) source files.
 *
 *  Source files should not include individual header files, as they
 *  have not been designed to be individually included.
 */

#if !defined(DUK_INTERNAL_H_INCLUDED)
#define DUK_INTERNAL_H_INCLUDED

/*
 *  The 'duktape.h' header provides the public API, but also handles all
 *  compiler and platform specific feature detection, Duktape feature
 *  resolution, inclusion of system headers, etc.  These have been merged
 *  because the public API is also dependent on e.g. detecting appropriate
 *  C types which is quite platform/compiler specific especially for a non-C99
 *  build.  The public API is also dependent on the resolved feature set.
 *
 *  Some actions taken by the merged header (such as including system headers)
 *  are not appropriate for building a user application.  The define
 *  DUK_COMPILING_DUKTAPE allows the merged header to skip/include some
 *  sections depending on what is being built.
 */

#define DUK_COMPILING_DUKTAPE
#include "duktape.h"

/*
 *  Duktape includes (other than duk_features.h)
 *
 *  The header files expect to be included in an order which satisfies header
 *  dependencies correctly (the headers themselves don't include any other
 *  includes).  Forward declarations are used to break circular struct/typedef
 *  dependencies.
 */

/* #include duk_dblunion.h */
/*
 *  Union to access IEEE double memory representation, indexes for double
 *  memory representation, and some macros for double manipulation.
 *
 *  Also used by packed duk_tval.  Use a union for bit manipulation to
 *  minimize aliasing issues in practice.  The C99 standard does not
 *  guarantee that this should work, but it's a very widely supported
 *  practice for low level manipulation.
 *
 *  IEEE double format summary:
 *
 *    seeeeeee eeeeffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
 *       A        B        C        D        E        F        G        H
 *
 *    s       sign bit
 *    eee...  exponent field
 *    fff...  fraction
 *
 *  See http://en.wikipedia.org/wiki/Double_precision_floating-point_format.
 *
 *  NaNs are represented as exponent 0x7ff and mantissa != 0.  The NaN is a
 *  signaling NaN when the highest bit of the mantissa is zero, and a quiet
 *  NaN when the highest bit is set.
 *
 *  At least three memory layouts are relevant here:
 *
 *    A B C D E F G H    Big endian (e.g. 68k)           DUK_USE_DOUBLE_BE
 *    H G F E D C B A    Little endian (e.g. x86)        DUK_USE_DOUBLE_LE
 *    D C B A H G F E    Mixed endian (e.g. ARM FPA)     DUK_USE_DOUBLE_ME
 *
 *  Legacy ARM (FPA) is a special case: ARM double values are in mixed
 *  endian format while ARM duk_uint64_t values are in standard little endian
 *  format (H G F E D C B A).  When a double is read as a duk_uint64_t
 *  from memory, the register will contain the (logical) value
 *  E F G H A B C D.  This requires some special handling below.
 *  See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0056d/Bcfhgcgd.html.
 *
 *  Indexes of various types (8-bit, 16-bit, 32-bit) in memory relative to
 *  the logical (big endian) order:
 *
 *  byte order      duk_uint8_t    duk_uint16_t     duk_uint32_t
 *    BE             01234567         0123               01
 *    LE             76543210         3210               10
 *    ME (ARM)       32107654         1032               01
 *
 *  Some processors may alter NaN values in a floating point load+store.
 *  For instance, on X86 a FLD + FSTP may convert a signaling NaN to a
 *  quiet one.  This is catastrophic when NaN space is used in packed
 *  duk_tval values.  See: misc/clang_aliasing.c.
 */

#if !defined(DUK_DBLUNION_H_INCLUDED)
#define DUK_DBLUNION_H_INCLUDED

/*
 *  Union for accessing double parts, also serves as packed duk_tval
 */

union duk_double_union {
	double d;
	float f[2];
#if defined(DUK_USE_64BIT_OPS)
	duk_uint64_t ull[1];
#endif
	duk_uint32_t ui[2];
	duk_uint16_t us[4];
	duk_uint8_t uc[8];
#if defined(DUK_USE_PACKED_TVAL)
	void *vp[2];  /* used by packed duk_tval, assumes sizeof(void *) == 4 */
#endif
};

typedef union duk_double_union duk_double_union;

/*
 *  Indexes of various types with respect to big endian (logical) layout
 */

#if defined(DUK_USE_DOUBLE_LE)
#if defined(DUK_USE_64BIT_OPS)
#define DUK_DBL_IDX_ULL0   0
#endif
#define DUK_DBL_IDX_UI0    1
#define DUK_DBL_IDX_UI1    0
#define DUK_DBL_IDX_US0    3
#define DUK_DBL_IDX_US1    2
#define DUK_DBL_IDX_US2    1
#define DUK_DBL_IDX_US3    0
#define DUK_DBL_IDX_UC0    7
#define DUK_DBL_IDX_UC1    6
#define DUK_DBL_IDX_UC2    5
#define DUK_DBL_IDX_UC3    4
#define DUK_DBL_IDX_UC4    3
#define DUK_DBL_IDX_UC5    2
#define DUK_DBL_IDX_UC6    1
#define DUK_DBL_IDX_UC7    0
#define DUK_DBL_IDX_VP0    DUK_DBL_IDX_UI0  /* packed tval */
#define DUK_DBL_IDX_VP1    DUK_DBL_IDX_UI1  /* packed tval */
#elif defined(DUK_USE_DOUBLE_BE)
#if defined(DUK_USE_64BIT_OPS)
#define DUK_DBL_IDX_ULL0   0
#endif
#define DUK_DBL_IDX_UI0    0
#define DUK_DBL_IDX_UI1    1
#define DUK_DBL_IDX_US0    0
#define DUK_DBL_IDX_US1    1
#define DUK_DBL_IDX_US2    2
#define DUK_DBL_IDX_US3    3
#define DUK_DBL_IDX_UC0    0
#define DUK_DBL_IDX_UC1    1
#define DUK_DBL_IDX_UC2    2
#define DUK_DBL_IDX_UC3    3
#define DUK_DBL_IDX_UC4    4
#define DUK_DBL_IDX_UC5    5
#define DUK_DBL_IDX_UC6    6
#define DUK_DBL_IDX_UC7    7
#define DUK_DBL_IDX_VP0    DUK_DBL_IDX_UI0  /* packed tval */
#define DUK_DBL_IDX_VP1    DUK_DBL_IDX_UI1  /* packed tval */
#elif defined(DUK_USE_DOUBLE_ME)
#if defined(DUK_USE_64BIT_OPS)
#define DUK_DBL_IDX_ULL0   0  /* not directly applicable, byte order differs from a double */
#endif
#define DUK_DBL_IDX_UI0    0
#define DUK_DBL_IDX_UI1    1
#define DUK_DBL_IDX_US0    1
#define DUK_DBL_IDX_US1    0
#define DUK_DBL_IDX_US2    3
#define DUK_DBL_IDX_US3    2
#define DUK_DBL_IDX_UC0    3
#define DUK_DBL_IDX_UC1    2
#define DUK_DBL_IDX_UC2    1
#define DUK_DBL_IDX_UC3    0
#define DUK_DBL_IDX_UC4    7
#define DUK_DBL_IDX_UC5    6
#define DUK_DBL_IDX_UC6    5
#define DUK_DBL_IDX_UC7    4
#define DUK_DBL_IDX_VP0    DUK_DBL_IDX_UI0  /* packed tval */
#define DUK_DBL_IDX_VP1    DUK_DBL_IDX_UI1  /* packed tval */
#else
#error internal error
#endif

/*
 *  Helper macros for reading/writing memory representation parts, used
 *  by duk_numconv.c and duk_tval.h.
 */

#define DUK_DBLUNION_SET_DOUBLE(u,v)  do {  \
		(u)->d = (v); \
	} while (0)

#define DUK_DBLUNION_SET_HIGH32(u,v)  do {  \
		(u)->ui[DUK_DBL_IDX_UI0] = (duk_uint32_t) (v); \
	} while (0)

#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
#define DUK_DBLUNION_SET_HIGH32_ZERO_LOW32(u,v)  do { \
		(u)->ull[DUK_DBL_IDX_ULL0] = (duk_uint64_t) (v); \
	} while (0)
#else
#define DUK_DBLUNION_SET_HIGH32_ZERO_LOW32(u,v)  do { \
		(u)->ull[DUK_DBL_IDX_ULL0] = ((duk_uint64_t) (v)) << 32; \
	} while (0)
#endif
#else  /* DUK_USE_64BIT_OPS */
#define DUK_DBLUNION_SET_HIGH32_ZERO_LOW32(u,v)  do { \
		(u)->ui[DUK_DBL_IDX_UI0] = (duk_uint32_t) (v); \
		(u)->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) 0; \
	} while (0)
#endif  /* DUK_USE_64BIT_OPS */

#define DUK_DBLUNION_SET_LOW32(u,v)  do {  \
		(u)->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (v); \
	} while (0)

#define DUK_DBLUNION_GET_DOUBLE(u)  ((u)->d)
#define DUK_DBLUNION_GET_HIGH32(u)  ((u)->ui[DUK_DBL_IDX_UI0])
#define DUK_DBLUNION_GET_LOW32(u)   ((u)->ui[DUK_DBL_IDX_UI1])

#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
#define DUK_DBLUNION_SET_UINT64(u,v)  do { \
		(u)->ui[DUK_DBL_IDX_UI0] = (duk_uint32_t) ((v) >> 32); \
		(u)->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (v); \
	} while (0)
#define DUK_DBLUNION_GET_UINT64(u) \
	((((duk_uint64_t) (u)->ui[DUK_DBL_IDX_UI0]) << 32) | \
	 ((duk_uint64_t) (u)->ui[DUK_DBL_IDX_UI1]))
#else
#define DUK_DBLUNION_SET_UINT64(u,v)  do { \
		(u)->ull[DUK_DBL_IDX_ULL0] = (duk_uint64_t) (v); \
	} while (0)
#define DUK_DBLUNION_GET_UINT64(u)  ((u)->ull[DUK_DBL_IDX_ULL0])
#endif
#define DUK_DBLUNION_SET_INT64(u,v) DUK_DBLUNION_SET_UINT64((u), (duk_uint64_t) (v))
#define DUK_DBLUNION_GET_INT64(u)   ((duk_int64_t) DUK_DBLUNION_GET_UINT64((u)))
#endif  /* DUK_USE_64BIT_OPS */

/*
 *  Double NaN manipulation macros related to NaN normalization needed when
 *  using the packed duk_tval representation.  NaN normalization is necessary
 *  to keep double values compatible with the duk_tval format.
 *
 *  When packed duk_tval is used, the NaN space is used to store pointers
 *  and other tagged values in addition to NaNs.  Actual NaNs are normalized
 *  to a specific quiet NaN.  The macros below are used by the implementation
 *  to check and normalize NaN values when they might be created.  The macros
 *  are essentially NOPs when the non-packed duk_tval representation is used.
 *
 *  A FULL check is exact and checks all bits.  A NOTFULL check is used by
 *  the packed duk_tval and works correctly for all NaNs except those that
 *  begin with 0x7ff0.  Since the 'normalized NaN' values used with packed
 *  duk_tval begin with 0x7ff8, the partial check is reliable when packed
 *  duk_tval is used.  The 0x7ff8 prefix means the normalized NaN will be a
 *  quiet NaN regardless of its remaining lower bits.
 *
 *  The ME variant below is specifically for ARM byte order, which has the
 *  feature that while doubles have a mixed byte order (32107654), unsigned
 *  long long values has a little endian byte order (76543210).  When writing
 *  a logical double value through a ULL pointer, the 32-bit words need to be
 *  swapped; hence the #if defined()s below for ULL writes with DUK_USE_DOUBLE_ME.
 *  This is not full ARM support but suffices for some environments.
 */

#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
/* Macros for 64-bit ops + mixed endian doubles. */
#define DUK__DBLUNION_SET_NAN_FULL(u)  do { \
		(u)->ull[DUK_DBL_IDX_ULL0] = DUK_U64_CONSTANT(0x000000007ff80000); \
	} while (0)
#define DUK__DBLUNION_IS_NAN_FULL(u) \
	((((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x000000007ff00000)) == DUK_U64_CONSTANT(0x000000007ff00000)) && \
	 ((((u)->ull[DUK_DBL_IDX_ULL0]) & DUK_U64_CONSTANT(0xffffffff000fffff)) != 0))
#define DUK__DBLUNION_IS_NORMALIZED_NAN_FULL(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x000000007ff80000))
#define DUK__DBLUNION_IS_ANYINF(u) \
	(((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0xffffffff7fffffff)) == DUK_U64_CONSTANT(0x000000007ff00000))
#define DUK__DBLUNION_IS_POSINF(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x000000007ff00000))
#define DUK__DBLUNION_IS_NEGINF(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x00000000fff00000))
#define DUK__DBLUNION_IS_ANYZERO(u) \
	(((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0xffffffff7fffffff)) == DUK_U64_CONSTANT(0x0000000000000000))
#define DUK__DBLUNION_IS_POSZERO(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x0000000000000000))
#define DUK__DBLUNION_IS_NEGZERO(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x0000000080000000))
#else
/* Macros for 64-bit ops + big/little endian doubles. */
#define DUK__DBLUNION_SET_NAN_FULL(u)  do { \
		(u)->ull[DUK_DBL_IDX_ULL0] = DUK_U64_CONSTANT(0x7ff8000000000000); \
	} while (0)
#define DUK__DBLUNION_IS_NAN_FULL(u) \
	((((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7ff0000000000000)) == DUK_U64_CONSTANT(0x7ff0000000000000)) && \
	 ((((u)->ull[DUK_DBL_IDX_ULL0]) & DUK_U64_CONSTANT(0x000fffffffffffff)) != 0))
#define DUK__DBLUNION_IS_NORMALIZED_NAN_FULL(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x7ff8000000000000))
#define DUK__DBLUNION_IS_ANYINF(u) \
	(((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7fffffffffffffff)) == DUK_U64_CONSTANT(0x7ff0000000000000))
#define DUK__DBLUNION_IS_POSINF(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x7ff0000000000000))
#define DUK__DBLUNION_IS_NEGINF(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0xfff0000000000000))
#define DUK__DBLUNION_IS_ANYZERO(u) \
	(((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7fffffffffffffff)) == DUK_U64_CONSTANT(0x0000000000000000))
#define DUK__DBLUNION_IS_POSZERO(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x0000000000000000))
#define DUK__DBLUNION_IS_NEGZERO(u) \
	((u)->ull[DUK_DBL_IDX_ULL0] == DUK_U64_CONSTANT(0x8000000000000000))
#endif
#else  /* DUK_USE_64BIT_OPS */
/* Macros for no 64-bit ops, any endianness. */
#define DUK__DBLUNION_SET_NAN_FULL(u)  do { \
		(u)->ui[DUK_DBL_IDX_UI0] = (duk_uint32_t) 0x7ff80000UL; \
		(u)->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) 0x00000000UL; \
	} while (0)
#define DUK__DBLUNION_IS_NAN_FULL(u) \
	((((u)->ui[DUK_DBL_IDX_UI0] & 0x7ff00000UL) == 0x7ff00000UL) && \
	 (((u)->ui[DUK_DBL_IDX_UI0] & 0x000fffffUL) != 0 || \
          (u)->ui[DUK_DBL_IDX_UI1] != 0))
#define DUK__DBLUNION_IS_NORMALIZED_NAN_FULL(u) \
	(((u)->ui[DUK_DBL_IDX_UI0] == 0x7ff80000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_ANYINF(u) \
	((((u)->ui[DUK_DBL_IDX_UI0] & 0x7fffffffUL) == 0x7ff00000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_POSINF(u) \
	(((u)->ui[DUK_DBL_IDX_UI0] == 0x7ff00000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_NEGINF(u) \
	(((u)->ui[DUK_DBL_IDX_UI0] == 0xfff00000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_ANYZERO(u) \
	((((u)->ui[DUK_DBL_IDX_UI0] & 0x7fffffffUL) == 0x00000000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_POSZERO(u) \
	(((u)->ui[DUK_DBL_IDX_UI0] == 0x00000000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#define DUK__DBLUNION_IS_NEGZERO(u) \
	(((u)->ui[DUK_DBL_IDX_UI0] == 0x80000000UL) && \
	 ((u)->ui[DUK_DBL_IDX_UI1] == 0x00000000UL))
#endif  /* DUK_USE_64BIT_OPS */

#define DUK__DBLUNION_SET_NAN_NOTFULL(u)  do { \
		(u)->us[DUK_DBL_IDX_US0] = 0x7ff8UL; \
	} while (0)

#define DUK__DBLUNION_IS_NAN_NOTFULL(u) \
	/* E == 0x7ff, topmost four bits of F != 0 => assume NaN */ \
	((((u)->us[DUK_DBL_IDX_US0] & 0x7ff0UL) == 0x7ff0UL) && \
	 (((u)->us[DUK_DBL_IDX_US0] & 0x000fUL) != 0x0000UL))

#define DUK__DBLUNION_IS_NORMALIZED_NAN_NOTFULL(u) \
	/* E == 0x7ff, F == 8 => normalized NaN */ \
	((u)->us[DUK_DBL_IDX_US0] == 0x7ff8UL)

#define DUK__DBLUNION_NORMALIZE_NAN_CHECK_FULL(u)  do { \
		if (DUK__DBLUNION_IS_NAN_FULL((u))) { \
			DUK__DBLUNION_SET_NAN_FULL((u)); \
		} \
	} while (0)

#define DUK__DBLUNION_NORMALIZE_NAN_CHECK_NOTFULL(u)  do { \
		if (DUK__DBLUNION_IS_NAN_NOTFULL((u))) { \
			DUK__DBLUNION_SET_NAN_NOTFULL((u)); \
		} \
	} while (0)

/* Concrete macros for NaN handling used by the implementation internals.
 * Chosen so that they match the duk_tval representation: with a packed
 * duk_tval, ensure NaNs are properly normalized; with a non-packed duk_tval
 * these are essentially NOPs.
 */

#if defined(DUK_USE_PACKED_TVAL)
#if defined(DUK_USE_FULL_TVAL)
#define DUK_DBLUNION_NORMALIZE_NAN_CHECK(u)  DUK__DBLUNION_NORMALIZE_NAN_CHECK_FULL((u))
#define DUK_DBLUNION_IS_NAN(u)               DUK__DBLUNION_IS_NAN_FULL((u))
#define DUK_DBLUNION_IS_NORMALIZED_NAN(u)    DUK__DBLUNION_IS_NORMALIZED_NAN_FULL((u))
#define DUK_DBLUNION_SET_NAN(d)              DUK__DBLUNION_SET_NAN_FULL((d))
#else
#define DUK_DBLUNION_NORMALIZE_NAN_CHECK(u)  DUK__DBLUNION_NORMALIZE_NAN_CHECK_NOTFULL((u))
#define DUK_DBLUNION_IS_NAN(u)               DUK__DBLUNION_IS_NAN_NOTFULL((u))
#define DUK_DBLUNION_IS_NORMALIZED_NAN(u)    DUK__DBLUNION_IS_NORMALIZED_NAN_NOTFULL((u))
#define DUK_DBLUNION_SET_NAN(d)              DUK__DBLUNION_SET_NAN_NOTFULL((d))
#endif
#define DUK_DBLUNION_IS_NORMALIZED(u) \
	(!DUK_DBLUNION_IS_NAN((u)) ||  /* either not a NaN */ \
	 DUK_DBLUNION_IS_NORMALIZED_NAN((u)))  /* or is a normalized NaN */
#else  /* DUK_USE_PACKED_TVAL */
#define DUK_DBLUNION_NORMALIZE_NAN_CHECK(u)  /* nop: no need to normalize */
#define DUK_DBLUNION_IS_NAN(u)               DUK__DBLUNION_IS_NAN_FULL((u))  /* (DUK_ISNAN((u)->d)) */
#define DUK_DBLUNION_IS_NORMALIZED_NAN(u)    DUK__DBLUNION_IS_NAN_FULL((u))  /* (DUK_ISNAN((u)->d)) */
#define DUK_DBLUNION_IS_NORMALIZED(u)        1  /* all doubles are considered normalized */
#define DUK_DBLUNION_SET_NAN(u)  do { \
		/* in non-packed representation we don't care about which NaN is used */ \
		(u)->d = DUK_DOUBLE_NAN; \
	} while (0)
#endif  /* DUK_USE_PACKED_TVAL */

#define DUK_DBLUNION_IS_ANYINF(u) DUK__DBLUNION_IS_ANYINF((u))
#define DUK_DBLUNION_IS_POSINF(u) DUK__DBLUNION_IS_POSINF((u))
#define DUK_DBLUNION_IS_NEGINF(u) DUK__DBLUNION_IS_NEGINF((u))

#define DUK_DBLUNION_IS_ANYZERO(u) DUK__DBLUNION_IS_ANYZERO((u))
#define DUK_DBLUNION_IS_POSZERO(u) DUK__DBLUNION_IS_POSZERO((u))
#define DUK_DBLUNION_IS_NEGZERO(u) DUK__DBLUNION_IS_NEGZERO((u))

/* XXX: native 64-bit byteswaps when available */

/* 64-bit byteswap, same operation independent of target endianness. */
#define DUK_DBLUNION_BSWAP64(u) do { \
		duk_uint32_t duk__bswaptmp1, duk__bswaptmp2; \
		duk__bswaptmp1 = (u)->ui[0]; \
		duk__bswaptmp2 = (u)->ui[1]; \
		duk__bswaptmp1 = DUK_BSWAP32(duk__bswaptmp1); \
		duk__bswaptmp2 = DUK_BSWAP32(duk__bswaptmp2); \
		(u)->ui[0] = duk__bswaptmp2; \
		(u)->ui[1] = duk__bswaptmp1; \
	} while (0)

/* Byteswap an IEEE double in the duk_double_union from host to network
 * order.  For a big endian target this is a no-op.
 */
#if defined(DUK_USE_DOUBLE_LE)
#define DUK_DBLUNION_DOUBLE_HTON(u) do { \
		duk_uint32_t duk__bswaptmp1, duk__bswaptmp2; \
		duk__bswaptmp1 = (u)->ui[0]; \
		duk__bswaptmp2 = (u)->ui[1]; \
		duk__bswaptmp1 = DUK_BSWAP32(duk__bswaptmp1); \
		duk__bswaptmp2 = DUK_BSWAP32(duk__bswaptmp2); \
		(u)->ui[0] = duk__bswaptmp2; \
		(u)->ui[1] = duk__bswaptmp1; \
	} while (0)
#elif defined(DUK_USE_DOUBLE_ME)
#define DUK_DBLUNION_DOUBLE_HTON(u) do { \
		duk_uint32_t duk__bswaptmp1, duk__bswaptmp2; \
		duk__bswaptmp1 = (u)->ui[0]; \
		duk__bswaptmp2 = (u)->ui[1]; \
		duk__bswaptmp1 = DUK_BSWAP32(duk__bswaptmp1); \
		duk__bswaptmp2 = DUK_BSWAP32(duk__bswaptmp2); \
		(u)->ui[0] = duk__bswaptmp1; \
		(u)->ui[1] = duk__bswaptmp2; \
	} while (0)
#elif defined(DUK_USE_DOUBLE_BE)
#define DUK_DBLUNION_DOUBLE_HTON(u) do { } while (0)
#else
#error internal error, double endianness insane
#endif

/* Reverse operation is the same. */
#define DUK_DBLUNION_DOUBLE_NTOH(u) DUK_DBLUNION_DOUBLE_HTON((u))

/* Some sign bit helpers. */
#if defined(DUK_USE_64BIT_OPS)
#define DUK_DBLUNION_HAS_SIGNBIT(u) (((u)->ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x8000000000000000)) != 0)
#define DUK_DBLUNION_GET_SIGNBIT(u) (((u)->ull[DUK_DBL_IDX_ULL0] >> 63U))
#else
#define DUK_DBLUNION_HAS_SIGNBIT(u) (((u)->ui[DUK_DBL_IDX_UI0] & 0x80000000UL) != 0)
#define DUK_DBLUNION_GET_SIGNBIT(u) (((u)->ui[DUK_DBL_IDX_UI0] >> 31U))
#endif

#endif  /* DUK_DBLUNION_H_INCLUDED */
/* #include duk_fltunion.h */
/*
 *  Union to access IEEE float memory representation.
 */

#if !defined(DUK_FLTUNION_H_INCLUDED)
#define DUK_FLTUNION_H_INCLUDED

/* #include duk_internal.h -> already included */

union duk_float_union {
	float f;
	duk_uint32_t ui[1];
	duk_uint16_t us[2];
	duk_uint8_t uc[4];
};

typedef union duk_float_union duk_float_union;

#if defined(DUK_USE_DOUBLE_LE) || defined(DUK_USE_DOUBLE_ME)
#define DUK_FLT_IDX_UI0    0
#define DUK_FLT_IDX_US0    1
#define DUK_FLT_IDX_US1    0
#define DUK_FLT_IDX_UC0    3
#define DUK_FLT_IDX_UC1    2
#define DUK_FLT_IDX_UC2    1
#define DUK_FLT_IDX_UC3    0
#elif defined(DUK_USE_DOUBLE_BE)
#define DUK_FLT_IDX_UI0    0
#define DUK_FLT_IDX_US0    0
#define DUK_FLT_IDX_US1    1
#define DUK_FLT_IDX_UC0    0
#define DUK_FLT_IDX_UC1    1
#define DUK_FLT_IDX_UC2    2
#define DUK_FLT_IDX_UC3    3
#else
#error internal error
#endif

#endif  /* DUK_FLTUNION_H_INCLUDED */
/* #include duk_replacements.h */
#if !defined(DUK_REPLACEMENTS_H_INCLUDED)
#define DUK_REPLACEMENTS_H_INCLUDED

#if !defined(DUK_SINGLE_FILE)
#if defined(DUK_USE_COMPUTED_INFINITY)
DUK_INTERNAL_DECL double duk_computed_infinity;
#endif
#if defined(DUK_USE_COMPUTED_NAN)
DUK_INTERNAL_DECL double duk_computed_nan;
#endif
#endif  /* !DUK_SINGLE_FILE */

#if defined(DUK_USE_REPL_FPCLASSIFY)
DUK_INTERNAL_DECL int duk_repl_fpclassify(double x);
#endif
#if defined(DUK_USE_REPL_SIGNBIT)
DUK_INTERNAL_DECL int duk_repl_signbit(double x);
#endif
#if defined(DUK_USE_REPL_ISFINITE)
DUK_INTERNAL_DECL int duk_repl_isfinite(double x);
#endif
#if defined(DUK_USE_REPL_ISNAN)
DUK_INTERNAL_DECL int duk_repl_isnan(double x);
#endif
#if defined(DUK_USE_REPL_ISINF)
DUK_INTERNAL_DECL int duk_repl_isinf(double x);
#endif

#endif  /* DUK_REPLACEMENTS_H_INCLUDED */
/* #include duk_jmpbuf.h */
/*
 *  Wrapper for jmp_buf.
 *
 *  This is used because jmp_buf is an array type for backward compatibility.
 *  Wrapping jmp_buf in a struct makes pointer references, sizeof, etc,
 *  behave more intuitively.
 *
 *  http://en.wikipedia.org/wiki/Setjmp.h#Member_types
 */

#if !defined(DUK_JMPBUF_H_INCLUDED)
#define DUK_JMPBUF_H_INCLUDED

#if defined(DUK_USE_CPP_EXCEPTIONS)
struct duk_jmpbuf {
	duk_small_int_t dummy;  /* unused */
};
#else
struct duk_jmpbuf {
	DUK_JMPBUF_TYPE jb;
};
#endif

#endif  /* DUK_JMPBUF_H_INCLUDED */
/* #include duk_exception.h */
/*
 *  Exceptions for Duktape internal throws when C++ exceptions are used
 *  for long control transfers.
 */

#if !defined(DUK_EXCEPTION_H_INCLUDED)
#define DUK_EXCEPTION_H_INCLUDED

#if defined(DUK_USE_CPP_EXCEPTIONS)
/* Internal exception used as a setjmp-longjmp replacement.  User code should
 * NEVER see or catch this exception, so it doesn't inherit from any base
 * class which should minimize the chance of user code accidentally catching
 * the exception.
 */
class duk_internal_exception {
	/* intentionally empty */
};

/* Fatal error, thrown as a specific C++ exception with C++ exceptions
 * enabled.  It is unsafe to continue; doing so may cause crashes or memory
 * leaks.  This is intended to be either uncaught, or caught by user code
 * aware of the "unsafe to continue" semantics.
 */
class duk_fatal_exception : public virtual std::runtime_error {
 public:
	duk_fatal_exception(const char *message) : std::runtime_error(message) {}
};
#endif

#endif  /* DUK_EXCEPTION_H_INCLUDED */
/* #include duk_forwdecl.h */
/*
 *  Forward declarations for all Duktape structures.
 */

#if !defined(DUK_FORWDECL_H_INCLUDED)
#define DUK_FORWDECL_H_INCLUDED

/*
 *  Forward declarations
 */

#if defined(DUK_USE_CPP_EXCEPTIONS)
class duk_internal_exception;
#else
struct duk_jmpbuf;
#endif

/* duk_tval intentionally skipped */
struct duk_heaphdr;
struct duk_heaphdr_string;
struct duk_harray;
struct duk_hstring;
struct duk_hstring_external;
struct duk_hobject;
struct duk_hcompfunc;
struct duk_hnatfunc;
struct duk_hboundfunc;
struct duk_hthread;
struct duk_hbufobj;
struct duk_hdecenv;
struct duk_hobjenv;
struct duk_hproxy;
struct duk_hbuffer;
struct duk_hbuffer_fixed;
struct duk_hbuffer_dynamic;
struct duk_hbuffer_external;

struct duk_propaccessor;
union duk_propvalue;
struct duk_propdesc;

struct duk_heap;
struct duk_breakpoint;

struct duk_activation;
struct duk_catcher;
struct duk_ljstate;
struct duk_strcache_entry;
struct duk_litcache_entry;
struct duk_strtab_entry;

#if defined(DUK_USE_DEBUG)
struct duk_fixedbuffer;
#endif

struct duk_bitdecoder_ctx;
struct duk_bitencoder_ctx;
struct duk_bufwriter_ctx;

struct duk_token;
struct duk_re_token;
struct duk_lexer_point;
struct duk_lexer_ctx;
struct duk_lexer_codepoint;

struct duk_compiler_instr;
struct duk_compiler_func;
struct duk_compiler_ctx;

struct duk_re_matcher_ctx;
struct duk_re_compiler_ctx;

#if defined(DUK_USE_CPP_EXCEPTIONS)
/* no typedef */
#else
typedef struct duk_jmpbuf duk_jmpbuf;
#endif

/* duk_tval intentionally skipped */
typedef struct duk_heaphdr duk_heaphdr;
typedef struct duk_heaphdr_string duk_heaphdr_string;
typedef struct duk_harray duk_harray;
typedef struct duk_hstring duk_hstring;
typedef struct duk_hstring_external duk_hstring_external;
typedef struct duk_hobject duk_hobject;
typedef struct duk_hcompfunc duk_hcompfunc;
typedef struct duk_hnatfunc duk_hnatfunc;
typedef struct duk_hboundfunc duk_hboundfunc;
typedef struct duk_hthread duk_hthread;
typedef struct duk_hbufobj duk_hbufobj;
typedef struct duk_hdecenv duk_hdecenv;
typedef struct duk_hobjenv duk_hobjenv;
typedef struct duk_hproxy duk_hproxy;
typedef struct duk_hbuffer duk_hbuffer;
typedef struct duk_hbuffer_fixed duk_hbuffer_fixed;
typedef struct duk_hbuffer_dynamic duk_hbuffer_dynamic;
typedef struct duk_hbuffer_external duk_hbuffer_external;

typedef struct duk_propaccessor duk_propaccessor;
typedef union duk_propvalue duk_propvalue;
typedef struct duk_propdesc duk_propdesc;

typedef struct duk_heap duk_heap;
typedef struct duk_breakpoint duk_breakpoint;

typedef struct duk_activation duk_activation;
typedef struct duk_catcher duk_catcher;
typedef struct duk_ljstate duk_ljstate;
typedef struct duk_strcache_entry duk_strcache_entry;
typedef struct duk_litcache_entry duk_litcache_entry;
typedef struct duk_strtab_entry duk_strtab_entry;

#if defined(DUK_USE_DEBUG)
typedef struct duk_fixedbuffer duk_fixedbuffer;
#endif

typedef struct duk_bitdecoder_ctx duk_bitdecoder_ctx;
typedef struct duk_bitencoder_ctx duk_bitencoder_ctx;
typedef struct duk_bufwriter_ctx duk_bufwriter_ctx;

typedef struct duk_token duk_token;
typedef struct duk_re_token duk_re_token;
typedef struct duk_lexer_point duk_lexer_point;
typedef struct duk_lexer_ctx duk_lexer_ctx;
typedef struct duk_lexer_codepoint duk_lexer_codepoint;

typedef struct duk_compiler_instr duk_compiler_instr;
typedef struct duk_compiler_func duk_compiler_func;
typedef struct duk_compiler_ctx duk_compiler_ctx;

typedef struct duk_re_matcher_ctx duk_re_matcher_ctx;
typedef struct duk_re_compiler_ctx duk_re_compiler_ctx;

#endif  /* DUK_FORWDECL_H_INCLUDED */
/* #include duk_tval.h */
/*
 *  Tagged type definition (duk_tval) and accessor macros.
 *
 *  Access all fields through the accessor macros, as the representation
 *  is quite tricky.
 *
 *  There are two packed type alternatives: an 8-byte representation
 *  based on an IEEE double (preferred for compactness), and a 12-byte
 *  representation (portability).  The latter is needed also in e.g.
 *  64-bit environments (it usually pads to 16 bytes per value).
 *
 *  Selecting the tagged type format involves many trade-offs (memory
 *  use, size and performance of generated code, portability, etc).
 *
 *  NB: because macro arguments are often expressions, macros should
 *  avoid evaluating their argument more than once.
 */

#if !defined(DUK_TVAL_H_INCLUDED)
#define DUK_TVAL_H_INCLUDED

/* sanity */
#if !defined(DUK_USE_DOUBLE_LE) && !defined(DUK_USE_DOUBLE_ME) && !defined(DUK_USE_DOUBLE_BE)
#error unsupported: cannot determine byte order variant
#endif

#if defined(DUK_USE_PACKED_TVAL)
/* ======================================================================== */

/*
 *  Packed 8-byte representation
 */

/* use duk_double_union as duk_tval directly */
typedef union duk_double_union duk_tval;
typedef struct {
	duk_uint16_t a;
	duk_uint16_t b;
	duk_uint16_t c;
	duk_uint16_t d;
} duk_tval_unused;

/* tags */
#define DUK_TAG_NORMALIZED_NAN    0x7ff8UL   /* the NaN variant we use */
/* avoid tag 0xfff0, no risk of confusion with negative infinity */
#define DUK_TAG_MIN               0xfff1UL
#if defined(DUK_USE_FASTINT)
#define DUK_TAG_FASTINT           0xfff1UL   /* embed: integer value */
#endif
#define DUK_TAG_UNUSED            0xfff2UL   /* marker; not actual tagged value */
#define DUK_TAG_UNDEFINED         0xfff3UL   /* embed: nothing */
#define DUK_TAG_NULL              0xfff4UL   /* embed: nothing */
#define DUK_TAG_BOOLEAN           0xfff5UL   /* embed: 0 or 1 (false or true) */
/* DUK_TAG_NUMBER would logically go here, but it has multiple 'tags' */
#define DUK_TAG_POINTER           0xfff6UL   /* embed: void ptr */
#define DUK_TAG_LIGHTFUNC         0xfff7UL   /* embed: func ptr */
#define DUK_TAG_STRING            0xfff8UL   /* embed: duk_hstring ptr */
#define DUK_TAG_OBJECT            0xfff9UL   /* embed: duk_hobject ptr */
#define DUK_TAG_BUFFER            0xfffaUL   /* embed: duk_hbuffer ptr */
#define DUK_TAG_MAX               0xfffaUL

/* for convenience */
#define DUK_XTAG_BOOLEAN_FALSE    0xfff50000UL
#define DUK_XTAG_BOOLEAN_TRUE     0xfff50001UL

#define DUK_TVAL_IS_VALID_TAG(tv) \
	(DUK_TVAL_GET_TAG((tv)) - DUK_TAG_MIN <= DUK_TAG_MAX - DUK_TAG_MIN)

/* DUK_TVAL_UNUSED initializer for duk_tval_unused, works for any endianness. */
#define DUK_TVAL_UNUSED_INITIALIZER() \
	{ DUK_TAG_UNUSED, DUK_TAG_UNUSED, DUK_TAG_UNUSED, DUK_TAG_UNUSED }

/* two casts to avoid gcc warning: "warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]" */
#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
#define DUK__TVAL_SET_TAGGEDPOINTER(tv,h,tag)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) (tag)) << 16) | (((duk_uint64_t) (duk_uint32_t) (h)) << 32); \
	} while (0)
#else
#define DUK__TVAL_SET_TAGGEDPOINTER(tv,h,tag)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) (tag)) << 48) | ((duk_uint64_t) (duk_uint32_t) (h)); \
	} while (0)
#endif
#else  /* DUK_USE_64BIT_OPS */
#define DUK__TVAL_SET_TAGGEDPOINTER(tv,h,tag)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->ui[DUK_DBL_IDX_UI0] = ((duk_uint32_t) (tag)) << 16; \
		duk__tv->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (h); \
	} while (0)
#endif  /* DUK_USE_64BIT_OPS */

#if defined(DUK_USE_64BIT_OPS)
/* Double casting for pointer to avoid gcc warning (cast from pointer to integer of different size) */
#if defined(DUK_USE_DOUBLE_ME)
#define DUK__TVAL_SET_LIGHTFUNC(tv,fp,flags)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) DUK_TAG_LIGHTFUNC) << 16) | \
		                              ((duk_uint64_t) (flags)) | \
		                              (((duk_uint64_t) (duk_uint32_t) (fp)) << 32); \
	} while (0)
#else
#define DUK__TVAL_SET_LIGHTFUNC(tv,fp,flags)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) DUK_TAG_LIGHTFUNC) << 48) | \
		                              (((duk_uint64_t) (flags)) << 32) | \
		                              ((duk_uint64_t) (duk_uint32_t) (fp)); \
	} while (0)
#endif
#else  /* DUK_USE_64BIT_OPS */
#define DUK__TVAL_SET_LIGHTFUNC(tv,fp,flags)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->ui[DUK_DBL_IDX_UI0] = (((duk_uint32_t) DUK_TAG_LIGHTFUNC) << 16) | ((duk_uint32_t) (flags)); \
		duk__tv->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (fp); \
	} while (0)
#endif  /* DUK_USE_64BIT_OPS */

#if defined(DUK_USE_FASTINT)
/* Note: masking is done for 'i' to deal with negative numbers correctly */
#if defined(DUK_USE_DOUBLE_ME)
#define DUK__TVAL_SET_I48(tv,i)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->ui[DUK_DBL_IDX_UI0] = ((duk_uint32_t) DUK_TAG_FASTINT) << 16 | (((duk_uint32_t) ((i) >> 32)) & 0x0000ffffUL); \
		duk__tv->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (i); \
	} while (0)
#define DUK__TVAL_SET_U32(tv,i)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->ui[DUK_DBL_IDX_UI0] = ((duk_uint32_t) DUK_TAG_FASTINT) << 16; \
		duk__tv->ui[DUK_DBL_IDX_UI1] = (duk_uint32_t) (i); \
	} while (0)
#else
#define DUK__TVAL_SET_I48(tv,i)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) DUK_TAG_FASTINT) << 48) | (((duk_uint64_t) (i)) & DUK_U64_CONSTANT(0x0000ffffffffffff)); \
	} while (0)
#define DUK__TVAL_SET_U32(tv,i)  do { \
		(tv)->ull[DUK_DBL_IDX_ULL0] = (((duk_uint64_t) DUK_TAG_FASTINT) << 48) | (duk_uint64_t) (i); \
	} while (0)
#endif

/* This needs to go through a cast because sign extension is needed. */
#define DUK__TVAL_SET_I32(tv,i)  do { \
		duk_int64_t duk__tmp = (duk_int64_t) (i); \
		DUK_TVAL_SET_I48((tv), duk__tmp); \
	} while (0)

/* XXX: Clumsy sign extend and masking of 16 topmost bits. */
#if defined(DUK_USE_DOUBLE_ME)
#define DUK__TVAL_GET_FASTINT(tv)      (((duk_int64_t) ((((duk_uint64_t) (tv)->ui[DUK_DBL_IDX_UI0]) << 32) | ((duk_uint64_t) (tv)->ui[DUK_DBL_IDX_UI1]))) << 16 >> 16)
#else
#define DUK__TVAL_GET_FASTINT(tv)      ((((duk_int64_t) (tv)->ull[DUK_DBL_IDX_ULL0]) << 16) >> 16)
#endif
#define DUK__TVAL_GET_FASTINT_U32(tv)  ((tv)->ui[DUK_DBL_IDX_UI1])
#define DUK__TVAL_GET_FASTINT_I32(tv)  ((duk_int32_t) (tv)->ui[DUK_DBL_IDX_UI1])
#endif  /* DUK_USE_FASTINT */

#define DUK_TVAL_SET_UNDEFINED(tv)  do { \
		(tv)->us[DUK_DBL_IDX_US0] = (duk_uint16_t) DUK_TAG_UNDEFINED; \
	} while (0)
#define DUK_TVAL_SET_UNUSED(tv)  do { \
		(tv)->us[DUK_DBL_IDX_US0] = (duk_uint16_t) DUK_TAG_UNUSED; \
	} while (0)
#define DUK_TVAL_SET_NULL(tv)  do { \
		(tv)->us[DUK_DBL_IDX_US0] = (duk_uint16_t) DUK_TAG_NULL; \
	} while (0)

#define DUK_TVAL_SET_BOOLEAN(tv,val)         DUK_DBLUNION_SET_HIGH32((tv), (((duk_uint32_t) DUK_TAG_BOOLEAN) << 16) | ((duk_uint32_t) (val)))

#define DUK_TVAL_SET_NAN(tv)                 DUK_DBLUNION_SET_NAN_FULL((tv))

/* Assumes that caller has normalized NaNs, otherwise trouble ahead. */
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_DOUBLE(tv,d)  do { \
		duk_double_t duk__dblval; \
		duk__dblval = (d); \
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(duk__dblval); \
		DUK_DBLUNION_SET_DOUBLE((tv), duk__dblval); \
	} while (0)
#define DUK_TVAL_SET_I48(tv,i)               DUK__TVAL_SET_I48((tv), (i))
#define DUK_TVAL_SET_I32(tv,i)               DUK__TVAL_SET_I32((tv), (i))
#define DUK_TVAL_SET_U32(tv,i)               DUK__TVAL_SET_U32((tv), (i))
#define DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv,d)  duk_tval_set_number_chkfast_fast((tv), (d))
#define DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(tv,d)  duk_tval_set_number_chkfast_slow((tv), (d))
#define DUK_TVAL_SET_NUMBER(tv,d)            DUK_TVAL_SET_DOUBLE((tv), (d))
#define DUK_TVAL_CHKFAST_INPLACE_FAST(tv)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__d; \
		duk__tv = (tv); \
		if (DUK_TVAL_IS_DOUBLE(duk__tv)) { \
			duk__d = DUK_TVAL_GET_DOUBLE(duk__tv); \
			DUK_TVAL_SET_NUMBER_CHKFAST_FAST(duk__tv, duk__d); \
		} \
	} while (0)
#define DUK_TVAL_CHKFAST_INPLACE_SLOW(tv)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__d; \
		duk__tv = (tv); \
		if (DUK_TVAL_IS_DOUBLE(duk__tv)) { \
			duk__d = DUK_TVAL_GET_DOUBLE(duk__tv); \
			DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(duk__tv, duk__d); \
		} \
	} while (0)
#else  /* DUK_USE_FASTINT */
#define DUK_TVAL_SET_DOUBLE(tv,d)  do { \
		duk_double_t duk__dblval; \
		duk__dblval = (d); \
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(duk__dblval); \
		DUK_DBLUNION_SET_DOUBLE((tv), duk__dblval); \
	} while (0)
#define DUK_TVAL_SET_I48(tv,i)               DUK_TVAL_SET_DOUBLE((tv), (duk_double_t) (i))  /* XXX: fast int-to-double */
#define DUK_TVAL_SET_I32(tv,i)               DUK_TVAL_SET_DOUBLE((tv), (duk_double_t) (i))
#define DUK_TVAL_SET_U32(tv,i)               DUK_TVAL_SET_DOUBLE((tv), (duk_double_t) (i))
#define DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv,d)    DUK_TVAL_SET_DOUBLE((tv), (d))
#define DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(tv,d)    DUK_TVAL_SET_DOUBLE((tv), (d))
#define DUK_TVAL_SET_NUMBER(tv,d)            DUK_TVAL_SET_DOUBLE((tv), (d))
#define DUK_TVAL_CHKFAST_INPLACE_FAST(tv)  do { } while (0)
#define DUK_TVAL_CHKFAST_INPLACE_SLOW(tv)  do { } while (0)
#endif  /* DUK_USE_FASTINT */

#define DUK_TVAL_SET_FASTINT(tv,i)           DUK_TVAL_SET_I48((tv), (i))  /* alias */

#define DUK_TVAL_SET_LIGHTFUNC(tv,fp,flags)  DUK__TVAL_SET_LIGHTFUNC((tv), (fp), (flags))
#define DUK_TVAL_SET_STRING(tv,h)            DUK__TVAL_SET_TAGGEDPOINTER((tv), (h), DUK_TAG_STRING)
#define DUK_TVAL_SET_OBJECT(tv,h)            DUK__TVAL_SET_TAGGEDPOINTER((tv), (h), DUK_TAG_OBJECT)
#define DUK_TVAL_SET_BUFFER(tv,h)            DUK__TVAL_SET_TAGGEDPOINTER((tv), (h), DUK_TAG_BUFFER)
#define DUK_TVAL_SET_POINTER(tv,p)           DUK__TVAL_SET_TAGGEDPOINTER((tv), (p), DUK_TAG_POINTER)

#define DUK_TVAL_SET_TVAL(tv,x)              do { *(tv) = *(x); } while (0)

/* getters */
#define DUK_TVAL_GET_BOOLEAN(tv)             ((duk_small_uint_t) (tv)->us[DUK_DBL_IDX_US1])
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_GET_DOUBLE(tv)              ((tv)->d)
#define DUK_TVAL_GET_FASTINT(tv)             DUK__TVAL_GET_FASTINT((tv))
#define DUK_TVAL_GET_FASTINT_U32(tv)         DUK__TVAL_GET_FASTINT_U32((tv))
#define DUK_TVAL_GET_FASTINT_I32(tv)         DUK__TVAL_GET_FASTINT_I32((tv))
#define DUK_TVAL_GET_NUMBER(tv)              duk_tval_get_number_packed((tv))
#else
#define DUK_TVAL_GET_NUMBER(tv)              ((tv)->d)
#define DUK_TVAL_GET_DOUBLE(tv)              ((tv)->d)
#endif
#define DUK_TVAL_GET_LIGHTFUNC(tv,out_fp,out_flags)  do { \
		(out_flags) = (tv)->ui[DUK_DBL_IDX_UI0] & 0xffffUL; \
		(out_fp) = (duk_c_function) (tv)->ui[DUK_DBL_IDX_UI1]; \
	} while (0)
#define DUK_TVAL_GET_LIGHTFUNC_FUNCPTR(tv)   ((duk_c_function) ((tv)->ui[DUK_DBL_IDX_UI1]))
#define DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv)     (((duk_small_uint_t) (tv)->ui[DUK_DBL_IDX_UI0]) & 0xffffUL)
#define DUK_TVAL_GET_STRING(tv)              ((duk_hstring *) (tv)->vp[DUK_DBL_IDX_VP1])
#define DUK_TVAL_GET_OBJECT(tv)              ((duk_hobject *) (tv)->vp[DUK_DBL_IDX_VP1])
#define DUK_TVAL_GET_BUFFER(tv)              ((duk_hbuffer *) (tv)->vp[DUK_DBL_IDX_VP1])
#define DUK_TVAL_GET_POINTER(tv)             ((void *) (tv)->vp[DUK_DBL_IDX_VP1])
#define DUK_TVAL_GET_HEAPHDR(tv)             ((duk_heaphdr *) (tv)->vp[DUK_DBL_IDX_VP1])

/* decoding */
#define DUK_TVAL_GET_TAG(tv)                 ((duk_small_uint_t) (tv)->us[DUK_DBL_IDX_US0])

#define DUK_TVAL_IS_UNDEFINED(tv)            (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_UNDEFINED)
#define DUK_TVAL_IS_UNUSED(tv)               (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_UNUSED)
#define DUK_TVAL_IS_NULL(tv)                 (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_NULL)
#define DUK_TVAL_IS_BOOLEAN(tv)              (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_BOOLEAN)
#define DUK_TVAL_IS_BOOLEAN_TRUE(tv)         ((tv)->ui[DUK_DBL_IDX_UI0] == DUK_XTAG_BOOLEAN_TRUE)
#define DUK_TVAL_IS_BOOLEAN_FALSE(tv)        ((tv)->ui[DUK_DBL_IDX_UI0] == DUK_XTAG_BOOLEAN_FALSE)
#define DUK_TVAL_IS_LIGHTFUNC(tv)            (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_LIGHTFUNC)
#define DUK_TVAL_IS_STRING(tv)               (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_STRING)
#define DUK_TVAL_IS_OBJECT(tv)               (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_OBJECT)
#define DUK_TVAL_IS_BUFFER(tv)               (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_BUFFER)
#define DUK_TVAL_IS_POINTER(tv)              (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_POINTER)
#if defined(DUK_USE_FASTINT)
/* 0xfff0 is -Infinity */
#define DUK_TVAL_IS_DOUBLE(tv)               (DUK_TVAL_GET_TAG((tv)) <= 0xfff0UL)
#define DUK_TVAL_IS_FASTINT(tv)              (DUK_TVAL_GET_TAG((tv)) == DUK_TAG_FASTINT)
#define DUK_TVAL_IS_NUMBER(tv)               (DUK_TVAL_GET_TAG((tv)) <= 0xfff1UL)
#else
#define DUK_TVAL_IS_NUMBER(tv)               (DUK_TVAL_GET_TAG((tv)) <= 0xfff0UL)
#define DUK_TVAL_IS_DOUBLE(tv)               DUK_TVAL_IS_NUMBER((tv))
#endif

/* This is performance critical because it appears in every DECREF. */
#define DUK_TVAL_IS_HEAP_ALLOCATED(tv)       (DUK_TVAL_GET_TAG((tv)) >= DUK_TAG_STRING)

#if defined(DUK_USE_FASTINT)
DUK_INTERNAL_DECL duk_double_t duk_tval_get_number_packed(duk_tval *tv);
#endif

#else  /* DUK_USE_PACKED_TVAL */
/* ======================================================================== */

/*
 *  Portable 12-byte representation
 */

/* Note: not initializing all bytes is normally not an issue: Duktape won't
 * read or use the uninitialized bytes so valgrind won't issue warnings.
 * In some special cases a harmless valgrind warning may be issued though.
 * For example, the DumpHeap debugger command writes out a compiled function's
 * 'data' area as is, including any uninitialized bytes, which causes a
 * valgrind warning.
 */

typedef struct duk_tval_struct duk_tval;

struct duk_tval_struct {
	duk_small_uint_t t;
	duk_small_uint_t v_extra;
	union {
		duk_double_t d;
		duk_small_int_t i;
#if defined(DUK_USE_FASTINT)
		duk_int64_t fi;  /* if present, forces 16-byte duk_tval */
#endif
		void *voidptr;
		duk_hstring *hstring;
		duk_hobject *hobject;
		duk_hcompfunc *hcompfunc;
		duk_hnatfunc *hnatfunc;
		duk_hthread *hthread;
		duk_hbuffer *hbuffer;
		duk_heaphdr *heaphdr;
		duk_c_function lightfunc;
	} v;
};

typedef struct {
	duk_small_uint_t t;
	duk_small_uint_t v_extra;
	/* The rest of the fields don't matter except for debug dumps and such
	 * for which a partial initializer may trigger out-ot-bounds memory
	 * reads.  Include a double field which is usually as large or larger
	 * than pointers (not always however).
	 */
	duk_double_t d;
} duk_tval_unused;

#define DUK_TVAL_UNUSED_INITIALIZER() \
	{ DUK_TAG_UNUSED, 0, 0.0 }

#define DUK_TAG_MIN                   0
#define DUK_TAG_NUMBER                0  /* DUK_TAG_NUMBER only defined for non-packed duk_tval */
#if defined(DUK_USE_FASTINT)
#define DUK_TAG_FASTINT               1
#endif
#define DUK_TAG_UNDEFINED             2
#define DUK_TAG_NULL                  3
#define DUK_TAG_BOOLEAN               4
#define DUK_TAG_POINTER               5
#define DUK_TAG_LIGHTFUNC             6
#define DUK_TAG_UNUSED                7  /* marker; not actual tagged type */
#define DUK_TAG_STRING                8  /* first heap allocated, match bit boundary */
#define DUK_TAG_OBJECT                9
#define DUK_TAG_BUFFER                10
#define DUK_TAG_MAX                   10

#define DUK_TVAL_IS_VALID_TAG(tv) \
	(DUK_TVAL_GET_TAG((tv)) - DUK_TAG_MIN <= DUK_TAG_MAX - DUK_TAG_MIN)

/* DUK_TAG_NUMBER is intentionally first, as it is the default clause in code
 * to support the 8-byte representation.  Further, it is a non-heap-allocated
 * type so it should come before DUK_TAG_STRING.  Finally, it should not break
 * the tag value ranges covered by case-clauses in a switch-case.
 */

/* setters */
#define DUK_TVAL_SET_UNDEFINED(tv)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_UNDEFINED; \
	} while (0)

#define DUK_TVAL_SET_UNUSED(tv)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_UNUSED; \
	} while (0)

#define DUK_TVAL_SET_NULL(tv)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_NULL; \
	} while (0)

#define DUK_TVAL_SET_BOOLEAN(tv,val)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_BOOLEAN; \
		duk__tv->v.i = (duk_small_int_t) (val); \
	} while (0)

#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_DOUBLE(tv,val)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__dblval; \
		duk__dblval = (val); \
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(duk__dblval); /* nop for unpacked duk_tval */ \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_NUMBER; \
		duk__tv->v.d = duk__dblval; \
	} while (0)
#define DUK_TVAL_SET_I48(tv,val)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_FASTINT; \
		duk__tv->v.fi = (val); \
	} while (0)
#define DUK_TVAL_SET_U32(tv,val)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_FASTINT; \
		duk__tv->v.fi = (duk_int64_t) (val); \
	} while (0)
#define DUK_TVAL_SET_I32(tv,val)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_FASTINT; \
		duk__tv->v.fi = (duk_int64_t) (val); \
	} while (0)
#define DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv,d) \
	duk_tval_set_number_chkfast_fast((tv), (d))
#define DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(tv,d) \
	duk_tval_set_number_chkfast_slow((tv), (d))
#define DUK_TVAL_SET_NUMBER(tv,val) \
	DUK_TVAL_SET_DOUBLE((tv), (val))
#define DUK_TVAL_CHKFAST_INPLACE_FAST(tv)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__d; \
		duk__tv = (tv); \
		if (DUK_TVAL_IS_DOUBLE(duk__tv)) { \
			duk__d = DUK_TVAL_GET_DOUBLE(duk__tv); \
			DUK_TVAL_SET_NUMBER_CHKFAST_FAST(duk__tv, duk__d); \
		} \
	} while (0)
#define DUK_TVAL_CHKFAST_INPLACE_SLOW(tv)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__d; \
		duk__tv = (tv); \
		if (DUK_TVAL_IS_DOUBLE(duk__tv)) { \
			duk__d = DUK_TVAL_GET_DOUBLE(duk__tv); \
			DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(duk__tv, duk__d); \
		} \
	} while (0)
#else  /* DUK_USE_FASTINT */
#define DUK_TVAL_SET_DOUBLE(tv,d) \
	DUK_TVAL_SET_NUMBER((tv), (d))
#define DUK_TVAL_SET_I48(tv,val) \
	DUK_TVAL_SET_NUMBER((tv), (duk_double_t) (val))  /* XXX: fast int-to-double */
#define DUK_TVAL_SET_U32(tv,val) \
	DUK_TVAL_SET_NUMBER((tv), (duk_double_t) (val))
#define DUK_TVAL_SET_I32(tv,val) \
	DUK_TVAL_SET_NUMBER((tv), (duk_double_t) (val))
#define DUK_TVAL_SET_NUMBER(tv,val)  do { \
		duk_tval *duk__tv; \
		duk_double_t duk__dblval; \
		duk__dblval = (val); \
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(duk__dblval); /* nop for unpacked duk_tval */ \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_NUMBER; \
		duk__tv->v.d = duk__dblval; \
	} while (0)
#define DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv,d) \
	DUK_TVAL_SET_NUMBER((tv), (d))
#define DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(tv,d) \
	DUK_TVAL_SET_NUMBER((tv), (d))
#define DUK_TVAL_CHKFAST_INPLACE_FAST(tv)  do { } while (0)
#define DUK_TVAL_CHKFAST_INPLACE_SLOW(tv)  do { } while (0)
#endif  /* DUK_USE_FASTINT */

#define DUK_TVAL_SET_FASTINT(tv,i) \
	DUK_TVAL_SET_I48((tv), (i))  /* alias */

#define DUK_TVAL_SET_POINTER(tv,hptr)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_POINTER; \
		duk__tv->v.voidptr = (hptr); \
	} while (0)

#define DUK_TVAL_SET_LIGHTFUNC(tv,fp,flags)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_LIGHTFUNC; \
		duk__tv->v_extra = (flags); \
		duk__tv->v.lightfunc = (duk_c_function) (fp); \
	} while (0)

#define DUK_TVAL_SET_STRING(tv,hptr)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_STRING; \
		duk__tv->v.hstring = (hptr); \
	} while (0)

#define DUK_TVAL_SET_OBJECT(tv,hptr)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_OBJECT; \
		duk__tv->v.hobject = (hptr); \
	} while (0)

#define DUK_TVAL_SET_BUFFER(tv,hptr)  do { \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_BUFFER; \
		duk__tv->v.hbuffer = (hptr); \
	} while (0)

#define DUK_TVAL_SET_NAN(tv)  do { \
		/* in non-packed representation we don't care about which NaN is used */ \
		duk_tval *duk__tv; \
		duk__tv = (tv); \
		duk__tv->t = DUK_TAG_NUMBER; \
		duk__tv->v.d = DUK_DOUBLE_NAN; \
	} while (0)

#define DUK_TVAL_SET_TVAL(tv,x)            do { *(tv) = *(x); } while (0)

/* getters */
#define DUK_TVAL_GET_BOOLEAN(tv)           ((duk_small_uint_t) (tv)->v.i)
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_GET_DOUBLE(tv)            ((tv)->v.d)
#define DUK_TVAL_GET_FASTINT(tv)           ((tv)->v.fi)
#define DUK_TVAL_GET_FASTINT_U32(tv)       ((duk_uint32_t) ((tv)->v.fi))
#define DUK_TVAL_GET_FASTINT_I32(tv)       ((duk_int32_t) ((tv)->v.fi))
#if 0
#define DUK_TVAL_GET_NUMBER(tv)            (DUK_TVAL_IS_FASTINT((tv)) ? \
                                               (duk_double_t) DUK_TVAL_GET_FASTINT((tv)) : \
                                               DUK_TVAL_GET_DOUBLE((tv)))
#define DUK_TVAL_GET_NUMBER(tv)            duk_tval_get_number_unpacked((tv))
#else
/* This seems reasonable overall. */
#define DUK_TVAL_GET_NUMBER(tv)            (DUK_TVAL_IS_FASTINT((tv)) ? \
                                               duk_tval_get_number_unpacked_fastint((tv)) : \
                                               DUK_TVAL_GET_DOUBLE((tv)))
#endif
#else
#define DUK_TVAL_GET_NUMBER(tv)            ((tv)->v.d)
#define DUK_TVAL_GET_DOUBLE(tv)            ((tv)->v.d)
#endif  /* DUK_USE_FASTINT */
#define DUK_TVAL_GET_POINTER(tv)           ((tv)->v.voidptr)
#define DUK_TVAL_GET_LIGHTFUNC(tv,out_fp,out_flags)  do { \
		(out_flags) = (duk_uint32_t) (tv)->v_extra; \
		(out_fp) = (tv)->v.lightfunc; \
	} while (0)
#define DUK_TVAL_GET_LIGHTFUNC_FUNCPTR(tv) ((tv)->v.lightfunc)
#define DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv)   ((duk_small_uint_t) ((tv)->v_extra))
#define DUK_TVAL_GET_STRING(tv)            ((tv)->v.hstring)
#define DUK_TVAL_GET_OBJECT(tv)            ((tv)->v.hobject)
#define DUK_TVAL_GET_BUFFER(tv)            ((tv)->v.hbuffer)
#define DUK_TVAL_GET_HEAPHDR(tv)           ((tv)->v.heaphdr)

/* decoding */
#define DUK_TVAL_GET_TAG(tv)               ((tv)->t)
#define DUK_TVAL_IS_UNDEFINED(tv)          ((tv)->t == DUK_TAG_UNDEFINED)
#define DUK_TVAL_IS_UNUSED(tv)             ((tv)->t == DUK_TAG_UNUSED)
#define DUK_TVAL_IS_NULL(tv)               ((tv)->t == DUK_TAG_NULL)
#define DUK_TVAL_IS_BOOLEAN(tv)            ((tv)->t == DUK_TAG_BOOLEAN)
#define DUK_TVAL_IS_BOOLEAN_TRUE(tv)       (((tv)->t == DUK_TAG_BOOLEAN) && ((tv)->v.i != 0))
#define DUK_TVAL_IS_BOOLEAN_FALSE(tv)      (((tv)->t == DUK_TAG_BOOLEAN) && ((tv)->v.i == 0))
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_IS_DOUBLE(tv)             ((tv)->t == DUK_TAG_NUMBER)
#define DUK_TVAL_IS_FASTINT(tv)            ((tv)->t == DUK_TAG_FASTINT)
#define DUK_TVAL_IS_NUMBER(tv)             ((tv)->t == DUK_TAG_NUMBER || \
                                            (tv)->t == DUK_TAG_FASTINT)
#else
#define DUK_TVAL_IS_NUMBER(tv)             ((tv)->t == DUK_TAG_NUMBER)
#define DUK_TVAL_IS_DOUBLE(tv)             DUK_TVAL_IS_NUMBER((tv))
#endif  /* DUK_USE_FASTINT */
#define DUK_TVAL_IS_POINTER(tv)            ((tv)->t == DUK_TAG_POINTER)
#define DUK_TVAL_IS_LIGHTFUNC(tv)          ((tv)->t == DUK_TAG_LIGHTFUNC)
#define DUK_TVAL_IS_STRING(tv)             ((tv)->t == DUK_TAG_STRING)
#define DUK_TVAL_IS_OBJECT(tv)             ((tv)->t == DUK_TAG_OBJECT)
#define DUK_TVAL_IS_BUFFER(tv)             ((tv)->t == DUK_TAG_BUFFER)

/* This is performance critical because it's needed for every DECREF.
 * Take advantage of the fact that the first heap allocated tag is 8,
 * so that bit 3 is set for all heap allocated tags (and never set for
 * non-heap-allocated tags).
 */
#if 0
#define DUK_TVAL_IS_HEAP_ALLOCATED(tv)     ((tv)->t >= DUK_TAG_STRING)
#endif
#define DUK_TVAL_IS_HEAP_ALLOCATED(tv)     ((tv)->t & 0x08)

#if defined(DUK_USE_FASTINT)
#if 0
DUK_INTERNAL_DECL duk_double_t duk_tval_get_number_unpacked(duk_tval *tv);
#endif
DUK_INTERNAL_DECL duk_double_t duk_tval_get_number_unpacked_fastint(duk_tval *tv);
#endif

#endif  /* DUK_USE_PACKED_TVAL */

/*
 *  Convenience (independent of representation)
 */

#define DUK_TVAL_SET_BOOLEAN_TRUE(tv)        DUK_TVAL_SET_BOOLEAN((tv), 1)
#define DUK_TVAL_SET_BOOLEAN_FALSE(tv)       DUK_TVAL_SET_BOOLEAN((tv), 0)

#define DUK_TVAL_STRING_IS_SYMBOL(tv) \
	DUK_HSTRING_HAS_SYMBOL(DUK_TVAL_GET_STRING((tv)))

/* Lightfunc flags packing and unpacking. */
/* Sign extend: 0x0000##00 -> 0x##000000 -> sign extend to 0xssssss##.
 * Avoid signed shifts due to portability limitations.
 */
#define DUK_LFUNC_FLAGS_GET_MAGIC(lf_flags) \
	((duk_int32_t) (duk_int8_t) (((duk_uint16_t) (lf_flags)) >> 8))
#define DUK_LFUNC_FLAGS_GET_LENGTH(lf_flags) \
	(((lf_flags) >> 4) & 0x0fU)
#define DUK_LFUNC_FLAGS_GET_NARGS(lf_flags) \
	((lf_flags) & 0x0fU)
#define DUK_LFUNC_FLAGS_PACK(magic,length,nargs) \
	((((duk_small_uint_t) (magic)) & 0xffU) << 8) | ((length) << 4) | (nargs)

#define DUK_LFUNC_NARGS_VARARGS             0x0f   /* varargs marker */
#define DUK_LFUNC_NARGS_MIN                 0x00
#define DUK_LFUNC_NARGS_MAX                 0x0e   /* max, excl. varargs marker */
#define DUK_LFUNC_LENGTH_MIN                0x00
#define DUK_LFUNC_LENGTH_MAX                0x0f
#define DUK_LFUNC_MAGIC_MIN                 (-0x80)
#define DUK_LFUNC_MAGIC_MAX                 0x7f

/* fastint constants etc */
#if defined(DUK_USE_FASTINT)
#define DUK_FASTINT_MIN           (DUK_I64_CONSTANT(-0x800000000000))
#define DUK_FASTINT_MAX           (DUK_I64_CONSTANT(0x7fffffffffff))
#define DUK_FASTINT_BITS          48

DUK_INTERNAL_DECL void duk_tval_set_number_chkfast_fast(duk_tval *tv, duk_double_t x);
DUK_INTERNAL_DECL void duk_tval_set_number_chkfast_slow(duk_tval *tv, duk_double_t x);
#endif

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_tval_assert_valid(duk_tval *tv);
#define DUK_TVAL_ASSERT_VALID(tv)  do { duk_tval_assert_valid((tv)); } while (0)
#else
#define DUK_TVAL_ASSERT_VALID(tv)  do {} while (0)
#endif

#endif  /* DUK_TVAL_H_INCLUDED */
/* #include duk_builtins.h */
/*
 *  Automatically generated by genbuiltins.py, do not edit!
 */

#if !defined(DUK_BUILTINS_H_INCLUDED)
#define DUK_BUILTINS_H_INCLUDED

#if defined(DUK_USE_ROM_STRINGS)
#error ROM support not enabled, rerun configure.py with --rom-support
#else  /* DUK_USE_ROM_STRINGS */
#define DUK_STRIDX_UC_UNDEFINED                                       0                              /* 'Undefined' */
#define DUK_HEAP_STRING_UC_UNDEFINED(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_UNDEFINED)
#define DUK_HTHREAD_STRING_UC_UNDEFINED(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_UNDEFINED)
#define DUK_STRIDX_UC_NULL                                            1                              /* 'Null' */
#define DUK_HEAP_STRING_UC_NULL(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_NULL)
#define DUK_HTHREAD_STRING_UC_NULL(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_NULL)
#define DUK_STRIDX_UC_SYMBOL                                          2                              /* 'Symbol' */
#define DUK_HEAP_STRING_UC_SYMBOL(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_SYMBOL)
#define DUK_HTHREAD_STRING_UC_SYMBOL(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_SYMBOL)
#define DUK_STRIDX_UC_ARGUMENTS                                       3                              /* 'Arguments' */
#define DUK_HEAP_STRING_UC_ARGUMENTS(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_ARGUMENTS)
#define DUK_HTHREAD_STRING_UC_ARGUMENTS(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_ARGUMENTS)
#define DUK_STRIDX_UC_OBJECT                                          4                              /* 'Object' */
#define DUK_HEAP_STRING_UC_OBJECT(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_OBJECT)
#define DUK_HTHREAD_STRING_UC_OBJECT(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_OBJECT)
#define DUK_STRIDX_UC_FUNCTION                                        5                              /* 'Function' */
#define DUK_HEAP_STRING_UC_FUNCTION(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_FUNCTION)
#define DUK_HTHREAD_STRING_UC_FUNCTION(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_FUNCTION)
#define DUK_STRIDX_UC_ARRAY                                           6                              /* 'Array' */
#define DUK_HEAP_STRING_UC_ARRAY(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_ARRAY)
#define DUK_HTHREAD_STRING_UC_ARRAY(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_ARRAY)
#define DUK_STRIDX_UC_STRING                                          7                              /* 'String' */
#define DUK_HEAP_STRING_UC_STRING(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_STRING)
#define DUK_HTHREAD_STRING_UC_STRING(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_STRING)
#define DUK_STRIDX_UC_BOOLEAN                                         8                              /* 'Boolean' */
#define DUK_HEAP_STRING_UC_BOOLEAN(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_BOOLEAN)
#define DUK_HTHREAD_STRING_UC_BOOLEAN(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_BOOLEAN)
#define DUK_STRIDX_UC_NUMBER                                          9                              /* 'Number' */
#define DUK_HEAP_STRING_UC_NUMBER(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_NUMBER)
#define DUK_HTHREAD_STRING_UC_NUMBER(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_NUMBER)
#define DUK_STRIDX_UC_DATE                                            10                             /* 'Date' */
#define DUK_HEAP_STRING_UC_DATE(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_DATE)
#define DUK_HTHREAD_STRING_UC_DATE(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_DATE)
#define DUK_STRIDX_REG_EXP                                            11                             /* 'RegExp' */
#define DUK_HEAP_STRING_REG_EXP(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_REG_EXP)
#define DUK_HTHREAD_STRING_REG_EXP(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_REG_EXP)
#define DUK_STRIDX_UC_ERROR                                           12                             /* 'Error' */
#define DUK_HEAP_STRING_UC_ERROR(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_ERROR)
#define DUK_HTHREAD_STRING_UC_ERROR(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_ERROR)
#define DUK_STRIDX_MATH                                               13                             /* 'Math' */
#define DUK_HEAP_STRING_MATH(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_MATH)
#define DUK_HTHREAD_STRING_MATH(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_MATH)
#define DUK_STRIDX_JSON                                               14                             /* 'JSON' */
#define DUK_HEAP_STRING_JSON(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON)
#define DUK_HTHREAD_STRING_JSON(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON)
#define DUK_STRIDX_EMPTY_STRING                                       15                             /* '' */
#define DUK_HEAP_STRING_EMPTY_STRING(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_EMPTY_STRING)
#define DUK_HTHREAD_STRING_EMPTY_STRING(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_EMPTY_STRING)
#define DUK_STRIDX_ARRAY_BUFFER                                       16                             /* 'ArrayBuffer' */
#define DUK_HEAP_STRING_ARRAY_BUFFER(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ARRAY_BUFFER)
#define DUK_HTHREAD_STRING_ARRAY_BUFFER(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ARRAY_BUFFER)
#define DUK_STRIDX_DATA_VIEW                                          17                             /* 'DataView' */
#define DUK_HEAP_STRING_DATA_VIEW(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DATA_VIEW)
#define DUK_HTHREAD_STRING_DATA_VIEW(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DATA_VIEW)
#define DUK_STRIDX_INT8_ARRAY                                         18                             /* 'Int8Array' */
#define DUK_HEAP_STRING_INT8_ARRAY(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT8_ARRAY)
#define DUK_HTHREAD_STRING_INT8_ARRAY(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT8_ARRAY)
#define DUK_STRIDX_UINT8_ARRAY                                        19                             /* 'Uint8Array' */
#define DUK_HEAP_STRING_UINT8_ARRAY(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UINT8_ARRAY)
#define DUK_HTHREAD_STRING_UINT8_ARRAY(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UINT8_ARRAY)
#define DUK_STRIDX_UINT8_CLAMPED_ARRAY                                20                             /* 'Uint8ClampedArray' */
#define DUK_HEAP_STRING_UINT8_CLAMPED_ARRAY(heap)                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UINT8_CLAMPED_ARRAY)
#define DUK_HTHREAD_STRING_UINT8_CLAMPED_ARRAY(thr)                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UINT8_CLAMPED_ARRAY)
#define DUK_STRIDX_INT16_ARRAY                                        21                             /* 'Int16Array' */
#define DUK_HEAP_STRING_INT16_ARRAY(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT16_ARRAY)
#define DUK_HTHREAD_STRING_INT16_ARRAY(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT16_ARRAY)
#define DUK_STRIDX_UINT16_ARRAY                                       22                             /* 'Uint16Array' */
#define DUK_HEAP_STRING_UINT16_ARRAY(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UINT16_ARRAY)
#define DUK_HTHREAD_STRING_UINT16_ARRAY(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UINT16_ARRAY)
#define DUK_STRIDX_INT32_ARRAY                                        23                             /* 'Int32Array' */
#define DUK_HEAP_STRING_INT32_ARRAY(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT32_ARRAY)
#define DUK_HTHREAD_STRING_INT32_ARRAY(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT32_ARRAY)
#define DUK_STRIDX_UINT32_ARRAY                                       24                             /* 'Uint32Array' */
#define DUK_HEAP_STRING_UINT32_ARRAY(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UINT32_ARRAY)
#define DUK_HTHREAD_STRING_UINT32_ARRAY(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UINT32_ARRAY)
#define DUK_STRIDX_FLOAT32_ARRAY                                      25                             /* 'Float32Array' */
#define DUK_HEAP_STRING_FLOAT32_ARRAY(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FLOAT32_ARRAY)
#define DUK_HTHREAD_STRING_FLOAT32_ARRAY(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FLOAT32_ARRAY)
#define DUK_STRIDX_FLOAT64_ARRAY                                      26                             /* 'Float64Array' */
#define DUK_HEAP_STRING_FLOAT64_ARRAY(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FLOAT64_ARRAY)
#define DUK_HTHREAD_STRING_FLOAT64_ARRAY(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FLOAT64_ARRAY)
#define DUK_STRIDX_GLOBAL                                             27                             /* 'global' */
#define DUK_HEAP_STRING_GLOBAL(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_GLOBAL)
#define DUK_HTHREAD_STRING_GLOBAL(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_GLOBAL)
#define DUK_STRIDX_OBJ_ENV                                            28                             /* 'ObjEnv' */
#define DUK_HEAP_STRING_OBJ_ENV(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_OBJ_ENV)
#define DUK_HTHREAD_STRING_OBJ_ENV(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_OBJ_ENV)
#define DUK_STRIDX_DEC_ENV                                            29                             /* 'DecEnv' */
#define DUK_HEAP_STRING_DEC_ENV(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DEC_ENV)
#define DUK_HTHREAD_STRING_DEC_ENV(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DEC_ENV)
#define DUK_STRIDX_UC_BUFFER                                          30                             /* 'Buffer' */
#define DUK_HEAP_STRING_UC_BUFFER(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_BUFFER)
#define DUK_HTHREAD_STRING_UC_BUFFER(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_BUFFER)
#define DUK_STRIDX_UC_POINTER                                         31                             /* 'Pointer' */
#define DUK_HEAP_STRING_UC_POINTER(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_POINTER)
#define DUK_HTHREAD_STRING_UC_POINTER(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_POINTER)
#define DUK_STRIDX_UC_THREAD                                          32                             /* 'Thread' */
#define DUK_HEAP_STRING_UC_THREAD(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_UC_THREAD)
#define DUK_HTHREAD_STRING_UC_THREAD(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_UC_THREAD)
#define DUK_STRIDX_EVAL                                               33                             /* 'eval' */
#define DUK_HEAP_STRING_EVAL(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_EVAL)
#define DUK_HTHREAD_STRING_EVAL(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_EVAL)
#define DUK_STRIDX_VALUE                                              34                             /* 'value' */
#define DUK_HEAP_STRING_VALUE(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_VALUE)
#define DUK_HTHREAD_STRING_VALUE(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_VALUE)
#define DUK_STRIDX_WRITABLE                                           35                             /* 'writable' */
#define DUK_HEAP_STRING_WRITABLE(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WRITABLE)
#define DUK_HTHREAD_STRING_WRITABLE(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WRITABLE)
#define DUK_STRIDX_CONFIGURABLE                                       36                             /* 'configurable' */
#define DUK_HEAP_STRING_CONFIGURABLE(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CONFIGURABLE)
#define DUK_HTHREAD_STRING_CONFIGURABLE(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CONFIGURABLE)
#define DUK_STRIDX_ENUMERABLE                                         37                             /* 'enumerable' */
#define DUK_HEAP_STRING_ENUMERABLE(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ENUMERABLE)
#define DUK_HTHREAD_STRING_ENUMERABLE(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ENUMERABLE)
#define DUK_STRIDX_JOIN                                               38                             /* 'join' */
#define DUK_HEAP_STRING_JOIN(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JOIN)
#define DUK_HTHREAD_STRING_JOIN(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JOIN)
#define DUK_STRIDX_TO_LOCALE_STRING                                   39                             /* 'toLocaleString' */
#define DUK_HEAP_STRING_TO_LOCALE_STRING(heap)                        DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_LOCALE_STRING)
#define DUK_HTHREAD_STRING_TO_LOCALE_STRING(thr)                      DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_LOCALE_STRING)
#define DUK_STRIDX_VALUE_OF                                           40                             /* 'valueOf' */
#define DUK_HEAP_STRING_VALUE_OF(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_VALUE_OF)
#define DUK_HTHREAD_STRING_VALUE_OF(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_VALUE_OF)
#define DUK_STRIDX_TO_UTC_STRING                                      41                             /* 'toUTCString' */
#define DUK_HEAP_STRING_TO_UTC_STRING(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_UTC_STRING)
#define DUK_HTHREAD_STRING_TO_UTC_STRING(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_UTC_STRING)
#define DUK_STRIDX_TO_ISO_STRING                                      42                             /* 'toISOString' */
#define DUK_HEAP_STRING_TO_ISO_STRING(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_ISO_STRING)
#define DUK_HTHREAD_STRING_TO_ISO_STRING(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_ISO_STRING)
#define DUK_STRIDX_TO_GMT_STRING                                      43                             /* 'toGMTString' */
#define DUK_HEAP_STRING_TO_GMT_STRING(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_GMT_STRING)
#define DUK_HTHREAD_STRING_TO_GMT_STRING(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_GMT_STRING)
#define DUK_STRIDX_SOURCE                                             44                             /* 'source' */
#define DUK_HEAP_STRING_SOURCE(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_SOURCE)
#define DUK_HTHREAD_STRING_SOURCE(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_SOURCE)
#define DUK_STRIDX_IGNORE_CASE                                        45                             /* 'ignoreCase' */
#define DUK_HEAP_STRING_IGNORE_CASE(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_IGNORE_CASE)
#define DUK_HTHREAD_STRING_IGNORE_CASE(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_IGNORE_CASE)
#define DUK_STRIDX_MULTILINE                                          46                             /* 'multiline' */
#define DUK_HEAP_STRING_MULTILINE(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_MULTILINE)
#define DUK_HTHREAD_STRING_MULTILINE(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_MULTILINE)
#define DUK_STRIDX_LAST_INDEX                                         47                             /* 'lastIndex' */
#define DUK_HEAP_STRING_LAST_INDEX(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LAST_INDEX)
#define DUK_HTHREAD_STRING_LAST_INDEX(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LAST_INDEX)
#define DUK_STRIDX_FLAGS                                              48                             /* 'flags' */
#define DUK_HEAP_STRING_FLAGS(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FLAGS)
#define DUK_HTHREAD_STRING_FLAGS(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FLAGS)
#define DUK_STRIDX_INDEX                                              49                             /* 'index' */
#define DUK_HEAP_STRING_INDEX(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INDEX)
#define DUK_HTHREAD_STRING_INDEX(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INDEX)
#define DUK_STRIDX_PROTOTYPE                                          50                             /* 'prototype' */
#define DUK_HEAP_STRING_PROTOTYPE(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PROTOTYPE)
#define DUK_HTHREAD_STRING_PROTOTYPE(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PROTOTYPE)
#define DUK_STRIDX_CONSTRUCTOR                                        51                             /* 'constructor' */
#define DUK_HEAP_STRING_CONSTRUCTOR(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CONSTRUCTOR)
#define DUK_HTHREAD_STRING_CONSTRUCTOR(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CONSTRUCTOR)
#define DUK_STRIDX_MESSAGE                                            52                             /* 'message' */
#define DUK_HEAP_STRING_MESSAGE(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_MESSAGE)
#define DUK_HTHREAD_STRING_MESSAGE(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_MESSAGE)
#define DUK_STRIDX_LC_BOOLEAN                                         53                             /* 'boolean' */
#define DUK_HEAP_STRING_LC_BOOLEAN(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_BOOLEAN)
#define DUK_HTHREAD_STRING_LC_BOOLEAN(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_BOOLEAN)
#define DUK_STRIDX_LC_NUMBER                                          54                             /* 'number' */
#define DUK_HEAP_STRING_LC_NUMBER(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_NUMBER)
#define DUK_HTHREAD_STRING_LC_NUMBER(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_NUMBER)
#define DUK_STRIDX_LC_STRING                                          55                             /* 'string' */
#define DUK_HEAP_STRING_LC_STRING(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_STRING)
#define DUK_HTHREAD_STRING_LC_STRING(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_STRING)
#define DUK_STRIDX_LC_SYMBOL                                          56                             /* 'symbol' */
#define DUK_HEAP_STRING_LC_SYMBOL(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_SYMBOL)
#define DUK_HTHREAD_STRING_LC_SYMBOL(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_SYMBOL)
#define DUK_STRIDX_LC_OBJECT                                          57                             /* 'object' */
#define DUK_HEAP_STRING_LC_OBJECT(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_OBJECT)
#define DUK_HTHREAD_STRING_LC_OBJECT(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_OBJECT)
#define DUK_STRIDX_LC_UNDEFINED                                       58                             /* 'undefined' */
#define DUK_HEAP_STRING_LC_UNDEFINED(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_UNDEFINED)
#define DUK_HTHREAD_STRING_LC_UNDEFINED(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_UNDEFINED)
#define DUK_STRIDX_NAN                                                59                             /* 'NaN' */
#define DUK_HEAP_STRING_NAN(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_NAN)
#define DUK_HTHREAD_STRING_NAN(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_NAN)
#define DUK_STRIDX_INFINITY                                           60                             /* 'Infinity' */
#define DUK_HEAP_STRING_INFINITY(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INFINITY)
#define DUK_HTHREAD_STRING_INFINITY(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INFINITY)
#define DUK_STRIDX_MINUS_INFINITY                                     61                             /* '-Infinity' */
#define DUK_HEAP_STRING_MINUS_INFINITY(heap)                          DUK_HEAP_GET_STRING((heap),DUK_STRIDX_MINUS_INFINITY)
#define DUK_HTHREAD_STRING_MINUS_INFINITY(thr)                        DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_MINUS_INFINITY)
#define DUK_STRIDX_MINUS_ZERO                                         62                             /* '-0' */
#define DUK_HEAP_STRING_MINUS_ZERO(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_MINUS_ZERO)
#define DUK_HTHREAD_STRING_MINUS_ZERO(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_MINUS_ZERO)
#define DUK_STRIDX_COMMA                                              63                             /* ',' */
#define DUK_HEAP_STRING_COMMA(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_COMMA)
#define DUK_HTHREAD_STRING_COMMA(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_COMMA)
#define DUK_STRIDX_NEWLINE_4SPACE                                     64                             /* '\n    ' */
#define DUK_HEAP_STRING_NEWLINE_4SPACE(heap)                          DUK_HEAP_GET_STRING((heap),DUK_STRIDX_NEWLINE_4SPACE)
#define DUK_HTHREAD_STRING_NEWLINE_4SPACE(thr)                        DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_NEWLINE_4SPACE)
#define DUK_STRIDX_BRACKETED_ELLIPSIS                                 65                             /* '[...]' */
#define DUK_HEAP_STRING_BRACKETED_ELLIPSIS(heap)                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_BRACKETED_ELLIPSIS)
#define DUK_HTHREAD_STRING_BRACKETED_ELLIPSIS(thr)                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_BRACKETED_ELLIPSIS)
#define DUK_STRIDX_INVALID_DATE                                       66                             /* 'Invalid Date' */
#define DUK_HEAP_STRING_INVALID_DATE(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INVALID_DATE)
#define DUK_HTHREAD_STRING_INVALID_DATE(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INVALID_DATE)
#define DUK_STRIDX_LC_ARGUMENTS                                       67                             /* 'arguments' */
#define DUK_HEAP_STRING_LC_ARGUMENTS(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_ARGUMENTS)
#define DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_ARGUMENTS)
#define DUK_STRIDX_CALLEE                                             68                             /* 'callee' */
#define DUK_HEAP_STRING_CALLEE(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CALLEE)
#define DUK_HTHREAD_STRING_CALLEE(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CALLEE)
#define DUK_STRIDX_CALLER                                             69                             /* 'caller' */
#define DUK_HEAP_STRING_CALLER(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CALLER)
#define DUK_HTHREAD_STRING_CALLER(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CALLER)
#define DUK_STRIDX_APPLY                                              70                             /* 'apply' */
#define DUK_HEAP_STRING_APPLY(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_APPLY)
#define DUK_HTHREAD_STRING_APPLY(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_APPLY)
#define DUK_STRIDX_CONSTRUCT                                          71                             /* 'construct' */
#define DUK_HEAP_STRING_CONSTRUCT(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CONSTRUCT)
#define DUK_HTHREAD_STRING_CONSTRUCT(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CONSTRUCT)
#define DUK_STRIDX_DELETE_PROPERTY                                    72                             /* 'deleteProperty' */
#define DUK_HEAP_STRING_DELETE_PROPERTY(heap)                         DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DELETE_PROPERTY)
#define DUK_HTHREAD_STRING_DELETE_PROPERTY(thr)                       DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DELETE_PROPERTY)
#define DUK_STRIDX_GET                                                73                             /* 'get' */
#define DUK_HEAP_STRING_GET(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_GET)
#define DUK_HTHREAD_STRING_GET(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_GET)
#define DUK_STRIDX_HAS                                                74                             /* 'has' */
#define DUK_HEAP_STRING_HAS(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_HAS)
#define DUK_HTHREAD_STRING_HAS(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_HAS)
#define DUK_STRIDX_OWN_KEYS                                           75                             /* 'ownKeys' */
#define DUK_HEAP_STRING_OWN_KEYS(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_OWN_KEYS)
#define DUK_HTHREAD_STRING_OWN_KEYS(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_OWN_KEYS)
#define DUK_STRIDX_WELLKNOWN_SYMBOL_TO_PRIMITIVE                      76                             /* '\x81Symbol.toPrimitive\xff' */
#define DUK_HEAP_STRING_WELLKNOWN_SYMBOL_TO_PRIMITIVE(heap)           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WELLKNOWN_SYMBOL_TO_PRIMITIVE)
#define DUK_HTHREAD_STRING_WELLKNOWN_SYMBOL_TO_PRIMITIVE(thr)         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WELLKNOWN_SYMBOL_TO_PRIMITIVE)
#define DUK_STRIDX_WELLKNOWN_SYMBOL_HAS_INSTANCE                      77                             /* '\x81Symbol.hasInstance\xff' */
#define DUK_HEAP_STRING_WELLKNOWN_SYMBOL_HAS_INSTANCE(heap)           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WELLKNOWN_SYMBOL_HAS_INSTANCE)
#define DUK_HTHREAD_STRING_WELLKNOWN_SYMBOL_HAS_INSTANCE(thr)         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WELLKNOWN_SYMBOL_HAS_INSTANCE)
#define DUK_STRIDX_WELLKNOWN_SYMBOL_TO_STRING_TAG                     78                             /* '\x81Symbol.toStringTag\xff' */
#define DUK_HEAP_STRING_WELLKNOWN_SYMBOL_TO_STRING_TAG(heap)          DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WELLKNOWN_SYMBOL_TO_STRING_TAG)
#define DUK_HTHREAD_STRING_WELLKNOWN_SYMBOL_TO_STRING_TAG(thr)        DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WELLKNOWN_SYMBOL_TO_STRING_TAG)
#define DUK_STRIDX_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE              79                             /* '\x81Symbol.isConcatSpreadable\xff' */
#define DUK_HEAP_STRING_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE(heap)   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE)
#define DUK_HTHREAD_STRING_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE(thr)  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE)
#define DUK_STRIDX_SET_PROTOTYPE_OF                                   80                             /* 'setPrototypeOf' */
#define DUK_HEAP_STRING_SET_PROTOTYPE_OF(heap)                        DUK_HEAP_GET_STRING((heap),DUK_STRIDX_SET_PROTOTYPE_OF)
#define DUK_HTHREAD_STRING_SET_PROTOTYPE_OF(thr)                      DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_SET_PROTOTYPE_OF)
#define DUK_STRIDX___PROTO__                                          81                             /* '__proto__' */
#define DUK_HEAP_STRING___PROTO__(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX___PROTO__)
#define DUK_HTHREAD_STRING___PROTO__(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX___PROTO__)
#define DUK_STRIDX_TO_STRING                                          82                             /* 'toString' */
#define DUK_HEAP_STRING_TO_STRING(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_STRING)
#define DUK_HTHREAD_STRING_TO_STRING(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_STRING)
#define DUK_STRIDX_TO_JSON                                            83                             /* 'toJSON' */
#define DUK_HEAP_STRING_TO_JSON(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TO_JSON)
#define DUK_HTHREAD_STRING_TO_JSON(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TO_JSON)
#define DUK_STRIDX_TYPE                                               84                             /* 'type' */
#define DUK_HEAP_STRING_TYPE(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TYPE)
#define DUK_HTHREAD_STRING_TYPE(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TYPE)
#define DUK_STRIDX_DATA                                               85                             /* 'data' */
#define DUK_HEAP_STRING_DATA(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DATA)
#define DUK_HTHREAD_STRING_DATA(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DATA)
#define DUK_STRIDX_LC_BUFFER                                          86                             /* 'buffer' */
#define DUK_HEAP_STRING_LC_BUFFER(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_BUFFER)
#define DUK_HTHREAD_STRING_LC_BUFFER(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_BUFFER)
#define DUK_STRIDX_LENGTH                                             87                             /* 'length' */
#define DUK_HEAP_STRING_LENGTH(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LENGTH)
#define DUK_HTHREAD_STRING_LENGTH(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LENGTH)
#define DUK_STRIDX_SET                                                88                             /* 'set' */
#define DUK_HEAP_STRING_SET(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_SET)
#define DUK_HTHREAD_STRING_SET(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_SET)
#define DUK_STRIDX_STACK                                              89                             /* 'stack' */
#define DUK_HEAP_STRING_STACK(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_STACK)
#define DUK_HTHREAD_STRING_STACK(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_STACK)
#define DUK_STRIDX_PC                                                 90                             /* 'pc' */
#define DUK_HEAP_STRING_PC(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PC)
#define DUK_HTHREAD_STRING_PC(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PC)
#define DUK_STRIDX_LINE_NUMBER                                        91                             /* 'lineNumber' */
#define DUK_HEAP_STRING_LINE_NUMBER(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LINE_NUMBER)
#define DUK_HTHREAD_STRING_LINE_NUMBER(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LINE_NUMBER)
#define DUK_STRIDX_INT_TRACEDATA                                      92                             /* '\x82Tracedata' */
#define DUK_HEAP_STRING_INT_TRACEDATA(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_TRACEDATA)
#define DUK_HTHREAD_STRING_INT_TRACEDATA(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_TRACEDATA)
#define DUK_STRIDX_NAME                                               93                             /* 'name' */
#define DUK_HEAP_STRING_NAME(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_NAME)
#define DUK_HTHREAD_STRING_NAME(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_NAME)
#define DUK_STRIDX_FILE_NAME                                          94                             /* 'fileName' */
#define DUK_HEAP_STRING_FILE_NAME(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FILE_NAME)
#define DUK_HTHREAD_STRING_FILE_NAME(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FILE_NAME)
#define DUK_STRIDX_LC_POINTER                                         95                             /* 'pointer' */
#define DUK_HEAP_STRING_LC_POINTER(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_POINTER)
#define DUK_HTHREAD_STRING_LC_POINTER(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_POINTER)
#define DUK_STRIDX_INT_TARGET                                         96                             /* '\x82Target' */
#define DUK_HEAP_STRING_INT_TARGET(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_TARGET)
#define DUK_HTHREAD_STRING_INT_TARGET(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_TARGET)
#define DUK_STRIDX_INT_NEXT                                           97                             /* '\x82Next' */
#define DUK_HEAP_STRING_INT_NEXT(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_NEXT)
#define DUK_HTHREAD_STRING_INT_NEXT(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_NEXT)
#define DUK_STRIDX_INT_BYTECODE                                       98                             /* '\x82Bytecode' */
#define DUK_HEAP_STRING_INT_BYTECODE(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_BYTECODE)
#define DUK_HTHREAD_STRING_INT_BYTECODE(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_BYTECODE)
#define DUK_STRIDX_INT_FORMALS                                        99                             /* '\x82Formals' */
#define DUK_HEAP_STRING_INT_FORMALS(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_FORMALS)
#define DUK_HTHREAD_STRING_INT_FORMALS(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_FORMALS)
#define DUK_STRIDX_INT_VARMAP                                         100                            /* '\x82Varmap' */
#define DUK_HEAP_STRING_INT_VARMAP(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_VARMAP)
#define DUK_HTHREAD_STRING_INT_VARMAP(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_VARMAP)
#define DUK_STRIDX_INT_SOURCE                                         101                            /* '\x82Source' */
#define DUK_HEAP_STRING_INT_SOURCE(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_SOURCE)
#define DUK_HTHREAD_STRING_INT_SOURCE(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_SOURCE)
#define DUK_STRIDX_INT_PC2LINE                                        102                            /* '\x82Pc2line' */
#define DUK_HEAP_STRING_INT_PC2LINE(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_PC2LINE)
#define DUK_HTHREAD_STRING_INT_PC2LINE(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_PC2LINE)
#define DUK_STRIDX_INT_MAP                                            103                            /* '\x82Map' */
#define DUK_HEAP_STRING_INT_MAP(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_MAP)
#define DUK_HTHREAD_STRING_INT_MAP(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_MAP)
#define DUK_STRIDX_INT_VARENV                                         104                            /* '\x82Varenv' */
#define DUK_HEAP_STRING_INT_VARENV(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_VARENV)
#define DUK_HTHREAD_STRING_INT_VARENV(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_VARENV)
#define DUK_STRIDX_INT_FINALIZER                                      105                            /* '\x82Finalizer' */
#define DUK_HEAP_STRING_INT_FINALIZER(heap)                           DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_FINALIZER)
#define DUK_HTHREAD_STRING_INT_FINALIZER(thr)                         DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_FINALIZER)
#define DUK_STRIDX_INT_VALUE                                          106                            /* '\x82Value' */
#define DUK_HEAP_STRING_INT_VALUE(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INT_VALUE)
#define DUK_HTHREAD_STRING_INT_VALUE(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INT_VALUE)
#define DUK_STRIDX_COMPILE                                            107                            /* 'compile' */
#define DUK_HEAP_STRING_COMPILE(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_COMPILE)
#define DUK_HTHREAD_STRING_COMPILE(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_COMPILE)
#define DUK_STRIDX_INPUT                                              108                            /* 'input' */
#define DUK_HEAP_STRING_INPUT(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INPUT)
#define DUK_HTHREAD_STRING_INPUT(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INPUT)
#define DUK_STRIDX_ERR_CREATE                                         109                            /* 'errCreate' */
#define DUK_HEAP_STRING_ERR_CREATE(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ERR_CREATE)
#define DUK_HTHREAD_STRING_ERR_CREATE(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ERR_CREATE)
#define DUK_STRIDX_ERR_THROW                                          110                            /* 'errThrow' */
#define DUK_HEAP_STRING_ERR_THROW(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ERR_THROW)
#define DUK_HTHREAD_STRING_ERR_THROW(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ERR_THROW)
#define DUK_STRIDX_ENV                                                111                            /* 'env' */
#define DUK_HEAP_STRING_ENV(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ENV)
#define DUK_HTHREAD_STRING_ENV(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ENV)
#define DUK_STRIDX_HEX                                                112                            /* 'hex' */
#define DUK_HEAP_STRING_HEX(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_HEX)
#define DUK_HTHREAD_STRING_HEX(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_HEX)
#define DUK_STRIDX_BASE64                                             113                            /* 'base64' */
#define DUK_HEAP_STRING_BASE64(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_BASE64)
#define DUK_HTHREAD_STRING_BASE64(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_BASE64)
#define DUK_STRIDX_JX                                                 114                            /* 'jx' */
#define DUK_HEAP_STRING_JX(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JX)
#define DUK_HTHREAD_STRING_JX(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JX)
#define DUK_STRIDX_JC                                                 115                            /* 'jc' */
#define DUK_HEAP_STRING_JC(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JC)
#define DUK_HTHREAD_STRING_JC(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JC)
#define DUK_STRIDX_JSON_EXT_UNDEFINED                                 116                            /* '{"_undef":true}' */
#define DUK_HEAP_STRING_JSON_EXT_UNDEFINED(heap)                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_UNDEFINED)
#define DUK_HTHREAD_STRING_JSON_EXT_UNDEFINED(thr)                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_UNDEFINED)
#define DUK_STRIDX_JSON_EXT_NAN                                       117                            /* '{"_nan":true}' */
#define DUK_HEAP_STRING_JSON_EXT_NAN(heap)                            DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_NAN)
#define DUK_HTHREAD_STRING_JSON_EXT_NAN(thr)                          DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_NAN)
#define DUK_STRIDX_JSON_EXT_POSINF                                    118                            /* '{"_inf":true}' */
#define DUK_HEAP_STRING_JSON_EXT_POSINF(heap)                         DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_POSINF)
#define DUK_HTHREAD_STRING_JSON_EXT_POSINF(thr)                       DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_POSINF)
#define DUK_STRIDX_JSON_EXT_NEGINF                                    119                            /* '{"_ninf":true}' */
#define DUK_HEAP_STRING_JSON_EXT_NEGINF(heap)                         DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_NEGINF)
#define DUK_HTHREAD_STRING_JSON_EXT_NEGINF(thr)                       DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_NEGINF)
#define DUK_STRIDX_JSON_EXT_FUNCTION1                                 120                            /* '{"_func":true}' */
#define DUK_HEAP_STRING_JSON_EXT_FUNCTION1(heap)                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_FUNCTION1)
#define DUK_HTHREAD_STRING_JSON_EXT_FUNCTION1(thr)                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_FUNCTION1)
#define DUK_STRIDX_JSON_EXT_FUNCTION2                                 121                            /* '{_func:true}' */
#define DUK_HEAP_STRING_JSON_EXT_FUNCTION2(heap)                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_JSON_EXT_FUNCTION2)
#define DUK_HTHREAD_STRING_JSON_EXT_FUNCTION2(thr)                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_JSON_EXT_FUNCTION2)
#define DUK_STRIDX_BREAK                                              122                            /* 'break' */
#define DUK_HEAP_STRING_BREAK(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_BREAK)
#define DUK_HTHREAD_STRING_BREAK(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_BREAK)
#define DUK_STRIDX_CASE                                               123                            /* 'case' */
#define DUK_HEAP_STRING_CASE(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CASE)
#define DUK_HTHREAD_STRING_CASE(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CASE)
#define DUK_STRIDX_CATCH                                              124                            /* 'catch' */
#define DUK_HEAP_STRING_CATCH(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CATCH)
#define DUK_HTHREAD_STRING_CATCH(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CATCH)
#define DUK_STRIDX_CONTINUE                                           125                            /* 'continue' */
#define DUK_HEAP_STRING_CONTINUE(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CONTINUE)
#define DUK_HTHREAD_STRING_CONTINUE(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CONTINUE)
#define DUK_STRIDX_DEBUGGER                                           126                            /* 'debugger' */
#define DUK_HEAP_STRING_DEBUGGER(heap)                                DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DEBUGGER)
#define DUK_HTHREAD_STRING_DEBUGGER(thr)                              DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DEBUGGER)
#define DUK_STRIDX_DEFAULT                                            127                            /* 'default' */
#define DUK_HEAP_STRING_DEFAULT(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DEFAULT)
#define DUK_HTHREAD_STRING_DEFAULT(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DEFAULT)
#define DUK_STRIDX_DELETE                                             128                            /* 'delete' */
#define DUK_HEAP_STRING_DELETE(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DELETE)
#define DUK_HTHREAD_STRING_DELETE(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DELETE)
#define DUK_STRIDX_DO                                                 129                            /* 'do' */
#define DUK_HEAP_STRING_DO(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_DO)
#define DUK_HTHREAD_STRING_DO(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_DO)
#define DUK_STRIDX_ELSE                                               130                            /* 'else' */
#define DUK_HEAP_STRING_ELSE(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ELSE)
#define DUK_HTHREAD_STRING_ELSE(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ELSE)
#define DUK_STRIDX_FINALLY                                            131                            /* 'finally' */
#define DUK_HEAP_STRING_FINALLY(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FINALLY)
#define DUK_HTHREAD_STRING_FINALLY(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FINALLY)
#define DUK_STRIDX_FOR                                                132                            /* 'for' */
#define DUK_HEAP_STRING_FOR(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FOR)
#define DUK_HTHREAD_STRING_FOR(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FOR)
#define DUK_STRIDX_LC_FUNCTION                                        133                            /* 'function' */
#define DUK_HEAP_STRING_LC_FUNCTION(heap)                             DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_FUNCTION)
#define DUK_HTHREAD_STRING_LC_FUNCTION(thr)                           DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_FUNCTION)
#define DUK_STRIDX_IF                                                 134                            /* 'if' */
#define DUK_HEAP_STRING_IF(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_IF)
#define DUK_HTHREAD_STRING_IF(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_IF)
#define DUK_STRIDX_IN                                                 135                            /* 'in' */
#define DUK_HEAP_STRING_IN(heap)                                      DUK_HEAP_GET_STRING((heap),DUK_STRIDX_IN)
#define DUK_HTHREAD_STRING_IN(thr)                                    DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_IN)
#define DUK_STRIDX_INSTANCEOF                                         136                            /* 'instanceof' */
#define DUK_HEAP_STRING_INSTANCEOF(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INSTANCEOF)
#define DUK_HTHREAD_STRING_INSTANCEOF(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INSTANCEOF)
#define DUK_STRIDX_NEW                                                137                            /* 'new' */
#define DUK_HEAP_STRING_NEW(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_NEW)
#define DUK_HTHREAD_STRING_NEW(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_NEW)
#define DUK_STRIDX_RETURN                                             138                            /* 'return' */
#define DUK_HEAP_STRING_RETURN(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_RETURN)
#define DUK_HTHREAD_STRING_RETURN(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_RETURN)
#define DUK_STRIDX_SWITCH                                             139                            /* 'switch' */
#define DUK_HEAP_STRING_SWITCH(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_SWITCH)
#define DUK_HTHREAD_STRING_SWITCH(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_SWITCH)
#define DUK_STRIDX_THIS                                               140                            /* 'this' */
#define DUK_HEAP_STRING_THIS(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_THIS)
#define DUK_HTHREAD_STRING_THIS(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_THIS)
#define DUK_STRIDX_THROW                                              141                            /* 'throw' */
#define DUK_HEAP_STRING_THROW(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_THROW)
#define DUK_HTHREAD_STRING_THROW(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_THROW)
#define DUK_STRIDX_TRY                                                142                            /* 'try' */
#define DUK_HEAP_STRING_TRY(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TRY)
#define DUK_HTHREAD_STRING_TRY(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TRY)
#define DUK_STRIDX_TYPEOF                                             143                            /* 'typeof' */
#define DUK_HEAP_STRING_TYPEOF(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TYPEOF)
#define DUK_HTHREAD_STRING_TYPEOF(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TYPEOF)
#define DUK_STRIDX_VAR                                                144                            /* 'var' */
#define DUK_HEAP_STRING_VAR(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_VAR)
#define DUK_HTHREAD_STRING_VAR(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_VAR)
#define DUK_STRIDX_CONST                                              145                            /* 'const' */
#define DUK_HEAP_STRING_CONST(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CONST)
#define DUK_HTHREAD_STRING_CONST(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CONST)
#define DUK_STRIDX_VOID                                               146                            /* 'void' */
#define DUK_HEAP_STRING_VOID(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_VOID)
#define DUK_HTHREAD_STRING_VOID(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_VOID)
#define DUK_STRIDX_WHILE                                              147                            /* 'while' */
#define DUK_HEAP_STRING_WHILE(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WHILE)
#define DUK_HTHREAD_STRING_WHILE(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WHILE)
#define DUK_STRIDX_WITH                                               148                            /* 'with' */
#define DUK_HEAP_STRING_WITH(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_WITH)
#define DUK_HTHREAD_STRING_WITH(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_WITH)
#define DUK_STRIDX_CLASS                                              149                            /* 'class' */
#define DUK_HEAP_STRING_CLASS(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_CLASS)
#define DUK_HTHREAD_STRING_CLASS(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_CLASS)
#define DUK_STRIDX_ENUM                                               150                            /* 'enum' */
#define DUK_HEAP_STRING_ENUM(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_ENUM)
#define DUK_HTHREAD_STRING_ENUM(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_ENUM)
#define DUK_STRIDX_EXPORT                                             151                            /* 'export' */
#define DUK_HEAP_STRING_EXPORT(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_EXPORT)
#define DUK_HTHREAD_STRING_EXPORT(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_EXPORT)
#define DUK_STRIDX_EXTENDS                                            152                            /* 'extends' */
#define DUK_HEAP_STRING_EXTENDS(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_EXTENDS)
#define DUK_HTHREAD_STRING_EXTENDS(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_EXTENDS)
#define DUK_STRIDX_IMPORT                                             153                            /* 'import' */
#define DUK_HEAP_STRING_IMPORT(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_IMPORT)
#define DUK_HTHREAD_STRING_IMPORT(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_IMPORT)
#define DUK_STRIDX_SUPER                                              154                            /* 'super' */
#define DUK_HEAP_STRING_SUPER(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_SUPER)
#define DUK_HTHREAD_STRING_SUPER(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_SUPER)
#define DUK_STRIDX_LC_NULL                                            155                            /* 'null' */
#define DUK_HEAP_STRING_LC_NULL(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LC_NULL)
#define DUK_HTHREAD_STRING_LC_NULL(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LC_NULL)
#define DUK_STRIDX_TRUE                                               156                            /* 'true' */
#define DUK_HEAP_STRING_TRUE(heap)                                    DUK_HEAP_GET_STRING((heap),DUK_STRIDX_TRUE)
#define DUK_HTHREAD_STRING_TRUE(thr)                                  DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_TRUE)
#define DUK_STRIDX_FALSE                                              157                            /* 'false' */
#define DUK_HEAP_STRING_FALSE(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_FALSE)
#define DUK_HTHREAD_STRING_FALSE(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_FALSE)
#define DUK_STRIDX_IMPLEMENTS                                         158                            /* 'implements' */
#define DUK_HEAP_STRING_IMPLEMENTS(heap)                              DUK_HEAP_GET_STRING((heap),DUK_STRIDX_IMPLEMENTS)
#define DUK_HTHREAD_STRING_IMPLEMENTS(thr)                            DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_IMPLEMENTS)
#define DUK_STRIDX_INTERFACE                                          159                            /* 'interface' */
#define DUK_HEAP_STRING_INTERFACE(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_INTERFACE)
#define DUK_HTHREAD_STRING_INTERFACE(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_INTERFACE)
#define DUK_STRIDX_LET                                                160                            /* 'let' */
#define DUK_HEAP_STRING_LET(heap)                                     DUK_HEAP_GET_STRING((heap),DUK_STRIDX_LET)
#define DUK_HTHREAD_STRING_LET(thr)                                   DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_LET)
#define DUK_STRIDX_PACKAGE                                            161                            /* 'package' */
#define DUK_HEAP_STRING_PACKAGE(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PACKAGE)
#define DUK_HTHREAD_STRING_PACKAGE(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PACKAGE)
#define DUK_STRIDX_PRIVATE                                            162                            /* 'private' */
#define DUK_HEAP_STRING_PRIVATE(heap)                                 DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PRIVATE)
#define DUK_HTHREAD_STRING_PRIVATE(thr)                               DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PRIVATE)
#define DUK_STRIDX_PROTECTED                                          163                            /* 'protected' */
#define DUK_HEAP_STRING_PROTECTED(heap)                               DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PROTECTED)
#define DUK_HTHREAD_STRING_PROTECTED(thr)                             DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PROTECTED)
#define DUK_STRIDX_PUBLIC                                             164                            /* 'public' */
#define DUK_HEAP_STRING_PUBLIC(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_PUBLIC)
#define DUK_HTHREAD_STRING_PUBLIC(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_PUBLIC)
#define DUK_STRIDX_STATIC                                             165                            /* 'static' */
#define DUK_HEAP_STRING_STATIC(heap)                                  DUK_HEAP_GET_STRING((heap),DUK_STRIDX_STATIC)
#define DUK_HTHREAD_STRING_STATIC(thr)                                DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_STATIC)
#define DUK_STRIDX_YIELD                                              166                            /* 'yield' */
#define DUK_HEAP_STRING_YIELD(heap)                                   DUK_HEAP_GET_STRING((heap),DUK_STRIDX_YIELD)
#define DUK_HTHREAD_STRING_YIELD(thr)                                 DUK_HTHREAD_GET_STRING((thr),DUK_STRIDX_YIELD)

#define DUK_HEAP_NUM_STRINGS                                          167
#define DUK_STRIDX_START_RESERVED                                     122
#define DUK_STRIDX_START_STRICT_RESERVED                              158
#define DUK_STRIDX_END_RESERVED                                       167                            /* exclusive endpoint */

/* To convert a heap stridx to a token number, subtract
 * DUK_STRIDX_START_RESERVED and add DUK_TOK_START_RESERVED.
 */
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_strings_data[972];
#endif  /* !DUK_SINGLE_FILE */
#define DUK_STRDATA_MAX_STRLEN                                        27
#define DUK_STRDATA_DATA_LENGTH                                       972
#endif  /* DUK_USE_ROM_STRINGS */

#if defined(DUK_USE_ROM_OBJECTS)
#error RAM support not enabled, rerun configure.py with --ram-support
#else  /* DUK_USE_ROM_OBJECTS */
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_boolean_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_constructor_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_type_error_thrower(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_parse_int(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_parse_float(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_thread_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_pointer_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_proxy_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_symbol_constructor_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_arraybuffer_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_dataview_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_typedarray_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textencoder_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textdecoder_constructor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_eval(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_is_nan(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_is_finite(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_decode_uri(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_decode_uri_component(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_encode_uri(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_encode_uri_component(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_escape(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_global_object_unescape(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_getprototype_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_setprototype_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_get_own_property_descriptor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_keys_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_assign(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_create(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_define_property(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_define_properties(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_seal_freeze_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_prevent_extensions(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_is_sealed_frozen_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_is_extensible(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_constructor_is(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_to_locale_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_value_of(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_has_own_property(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_is_prototype_of(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_property_is_enumerable(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_defineaccessor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_lookupaccessor(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype_apply(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype_call(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype_bind(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype_hasinstance(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_native_function_length(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_native_function_name(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_constructor_is_array(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_join_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_concat(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_pop(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_push(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_reverse(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_shift(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_slice(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_sort(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_splice(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_unshift(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_indexof_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_iter_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_array_prototype_reduce_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_constructor_from_char_code(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_constructor_from_code_point(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_char_at(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_char_code_at(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_concat(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_indexof_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_locale_compare(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_match(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_replace(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_search(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_slice(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_split(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_substring(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_caseconv_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_trim(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_repeat(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_startswith_endswith(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_includes(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_string_prototype_substr(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_boolean_prototype_tostring_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_check_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_to_locale_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_value_of(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_to_fixed(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_to_exponential(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_number_prototype_to_precision(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_constructor_parse(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_constructor_utc(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_constructor_now(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_tostring_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_to_json(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_value_of(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_get_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_get_timezone_offset(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_set_time(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_set_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_date_prototype_toprimitive(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_prototype_exec(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_prototype_test(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_prototype_tostring(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_prototype_flags(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_regexp_prototype_shared_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_stack_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_stack_setter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_filename_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_filename_setter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_linenumber_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_linenumber_setter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_error_prototype_to_string(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_onearg_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_twoarg_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_clz32(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_hypot(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_imul(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_max(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_min(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_random(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_math_object_sign(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_json_object_parse(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_json_object_stringify(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_info(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_act(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_gc(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_fin(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_enc(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_dec(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_duktape_object_compact(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_thread_yield(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_thread_resume(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_thread_current(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_pointer_prototype_tostring_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_apply(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_construct(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_object_delete_property(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_object_get(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_object_has(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_reflect_object_set(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_symbol_key_for(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_symbol_tostring_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_symbol_toprimitive(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_arraybuffer_isview(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_typedarray_bytelength_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_buffer_slice_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_typedarray_byteoffset_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_typedarray_buffer_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_buffer_readfield(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_buffer_writefield(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_typedarray_set(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_uint8array_allocplain(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_uint8array_plainof(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_concat(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_is_encoding(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_is_buffer(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_byte_length(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_buffer_compare_shared(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_tostring(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_tojson(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_fill(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_copy(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_nodejs_buffer_write(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_cbor_encode(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_cbor_decode(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textencoder_prototype_encoding_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textencoder_prototype_encode(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textdecoder_prototype_shared_getter(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_textdecoder_prototype_decode(duk_context *ctx);
DUK_INTERNAL_DECL duk_ret_t duk_bi_performance_now(duk_context *ctx);
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_c_function duk_bi_native_functions[185];
#endif  /* !DUK_SINGLE_FILE */
#define DUK_BIDX_GLOBAL                                               0
#define DUK_BIDX_GLOBAL_ENV                                           1
#define DUK_BIDX_OBJECT_CONSTRUCTOR                                   2
#define DUK_BIDX_OBJECT_PROTOTYPE                                     3
#define DUK_BIDX_FUNCTION_CONSTRUCTOR                                 4
#define DUK_BIDX_FUNCTION_PROTOTYPE                                   5
#define DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE                            6
#define DUK_BIDX_ARRAY_CONSTRUCTOR                                    7
#define DUK_BIDX_ARRAY_PROTOTYPE                                      8
#define DUK_BIDX_STRING_CONSTRUCTOR                                   9
#define DUK_BIDX_STRING_PROTOTYPE                                     10
#define DUK_BIDX_BOOLEAN_CONSTRUCTOR                                  11
#define DUK_BIDX_BOOLEAN_PROTOTYPE                                    12
#define DUK_BIDX_NUMBER_CONSTRUCTOR                                   13
#define DUK_BIDX_NUMBER_PROTOTYPE                                     14
#define DUK_BIDX_DATE_CONSTRUCTOR                                     15
#define DUK_BIDX_DATE_PROTOTYPE                                       16
#define DUK_BIDX_REGEXP_CONSTRUCTOR                                   17
#define DUK_BIDX_REGEXP_PROTOTYPE                                     18
#define DUK_BIDX_ERROR_CONSTRUCTOR                                    19
#define DUK_BIDX_ERROR_PROTOTYPE                                      20
#define DUK_BIDX_EVAL_ERROR_CONSTRUCTOR                               21
#define DUK_BIDX_EVAL_ERROR_PROTOTYPE                                 22
#define DUK_BIDX_RANGE_ERROR_CONSTRUCTOR                              23
#define DUK_BIDX_RANGE_ERROR_PROTOTYPE                                24
#define DUK_BIDX_REFERENCE_ERROR_CONSTRUCTOR                          25
#define DUK_BIDX_REFERENCE_ERROR_PROTOTYPE                            26
#define DUK_BIDX_SYNTAX_ERROR_CONSTRUCTOR                             27
#define DUK_BIDX_SYNTAX_ERROR_PROTOTYPE                               28
#define DUK_BIDX_TYPE_ERROR_CONSTRUCTOR                               29
#define DUK_BIDX_TYPE_ERROR_PROTOTYPE                                 30
#define DUK_BIDX_URI_ERROR_CONSTRUCTOR                                31
#define DUK_BIDX_URI_ERROR_PROTOTYPE                                  32
#define DUK_BIDX_TYPE_ERROR_THROWER                                   33
#define DUK_BIDX_DUKTAPE                                              34
#define DUK_BIDX_THREAD_PROTOTYPE                                     35
#define DUK_BIDX_POINTER_PROTOTYPE                                    36
#define DUK_BIDX_DOUBLE_ERROR                                         37
#define DUK_BIDX_SYMBOL_PROTOTYPE                                     38
#define DUK_BIDX_ARRAYBUFFER_PROTOTYPE                                39
#define DUK_BIDX_DATAVIEW_PROTOTYPE                                   40
#define DUK_BIDX_INT8ARRAY_PROTOTYPE                                  41
#define DUK_BIDX_UINT8ARRAY_PROTOTYPE                                 42
#define DUK_BIDX_UINT8CLAMPEDARRAY_PROTOTYPE                          43
#define DUK_BIDX_INT16ARRAY_PROTOTYPE                                 44
#define DUK_BIDX_UINT16ARRAY_PROTOTYPE                                45
#define DUK_BIDX_INT32ARRAY_PROTOTYPE                                 46
#define DUK_BIDX_UINT32ARRAY_PROTOTYPE                                47
#define DUK_BIDX_FLOAT32ARRAY_PROTOTYPE                               48
#define DUK_BIDX_FLOAT64ARRAY_PROTOTYPE                               49
#define DUK_BIDX_NODEJS_BUFFER_PROTOTYPE                              50
#define DUK_NUM_BUILTINS                                              51
#define DUK_NUM_BIDX_BUILTINS                                         51
#define DUK_NUM_ALL_BUILTINS                                          80
#if defined(DUK_USE_DOUBLE_LE)
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_builtins_data[4281];
#endif  /* !DUK_SINGLE_FILE */
#define DUK_BUILTINS_DATA_LENGTH                                      4281
#elif defined(DUK_USE_DOUBLE_BE)
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_builtins_data[4281];
#endif  /* !DUK_SINGLE_FILE */
#define DUK_BUILTINS_DATA_LENGTH                                      4281
#elif defined(DUK_USE_DOUBLE_ME)
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_builtins_data[4281];
#endif  /* !DUK_SINGLE_FILE */
#define DUK_BUILTINS_DATA_LENGTH                                      4281
#else
#error invalid endianness defines
#endif
#endif  /* DUK_USE_ROM_OBJECTS */
#endif  /* DUK_BUILTINS_H_INCLUDED */

/* #include duk_util.h */
/*
 *  Utilities
 */

#if !defined(DUK_UTIL_H_INCLUDED)
#define DUK_UTIL_H_INCLUDED

#if defined(DUK_USE_GET_RANDOM_DOUBLE)
#define DUK_UTIL_GET_RANDOM_DOUBLE(thr) DUK_USE_GET_RANDOM_DOUBLE((thr)->heap_udata)
#else
#define DUK_UTIL_GET_RANDOM_DOUBLE(thr) duk_util_tinyrandom_get_double(thr)
#endif

/*
 *  Some useful constants
 */

#define DUK_DOUBLE_2TO32     4294967296.0
#define DUK_DOUBLE_2TO31     2147483648.0
#define DUK_DOUBLE_LOG2E     1.4426950408889634
#define DUK_DOUBLE_LOG10E    0.4342944819032518

/*
 *  Endian conversion
 */

#if defined(DUK_USE_INTEGER_LE)
#define DUK_HTON32(x) DUK_BSWAP32((x))
#define DUK_NTOH32(x) DUK_BSWAP32((x))
#define DUK_HTON16(x) DUK_BSWAP16((x))
#define DUK_NTOH16(x) DUK_BSWAP16((x))
#elif defined(DUK_USE_INTEGER_BE)
#define DUK_HTON32(x) (x)
#define DUK_NTOH32(x) (x)
#define DUK_HTON16(x) (x)
#define DUK_NTOH16(x) (x)
#else
#error internal error, endianness defines broken
#endif

/*
 *  Bitstream decoder
 */

struct duk_bitdecoder_ctx {
	const duk_uint8_t *data;
	duk_size_t offset;
	duk_size_t length;
	duk_uint32_t currval;
	duk_small_int_t currbits;
};

#define DUK_BD_BITPACKED_STRING_MAXLEN 256

/*
 *  Bitstream encoder
 */

struct duk_bitencoder_ctx {
	duk_uint8_t *data;
	duk_size_t offset;
	duk_size_t length;
	duk_uint32_t currval;
	duk_small_int_t currbits;
	duk_small_int_t truncated;
};

/*
 *  Raw write/read macros for big endian, unaligned basic values.
 *  Caller ensures there's enough space.  The INC macro variants
 *  update the pointer argument automatically.
 */

#define DUK_RAW_WRITE_U8(ptr,val)  do { \
		*(ptr) = (duk_uint8_t) (val); \
	} while (0)
#define DUK_RAW_WRITE_U16_BE(ptr,val) duk_raw_write_u16_be((ptr), (duk_uint16_t) (val))
#define DUK_RAW_WRITE_U32_BE(ptr,val) duk_raw_write_u32_be((ptr), (duk_uint32_t) (val))
#define DUK_RAW_WRITE_FLOAT_BE(ptr,val) duk_raw_write_float_be((ptr), (duk_float_t) (val))
#define DUK_RAW_WRITE_DOUBLE_BE(ptr,val) duk_raw_write_double_be((ptr), (duk_double_t) (val))
#define DUK_RAW_WRITE_XUTF8(ptr,val) duk_raw_write_xutf8((ptr), (duk_ucodepoint_t) (val))

#define DUK_RAW_WRITEINC_U8(ptr,val)  do { \
		*(ptr)++ = (duk_uint8_t) (val); \
	} while (0)
#define DUK_RAW_WRITEINC_U16_BE(ptr,val) duk_raw_writeinc_u16_be(&(ptr), (duk_uint16_t) (val))
#define DUK_RAW_WRITEINC_U32_BE(ptr,val) duk_raw_writeinc_u32_be(&(ptr), (duk_uint32_t) (val))
#define DUK_RAW_WRITEINC_FLOAT_BE(ptr,val) duk_raw_writeinc_float_be(&(ptr), (duk_float_t) (val))
#define DUK_RAW_WRITEINC_DOUBLE_BE(ptr,val) duk_raw_writeinc_double_be(&(ptr), (duk_double_t) (val))
#define DUK_RAW_WRITEINC_XUTF8(ptr,val) duk_raw_writeinc_xutf8(&(ptr), (duk_ucodepoint_t) (val))
#define DUK_RAW_WRITEINC_CESU8(ptr,val) duk_raw_writeinc_cesu8(&(ptr), (duk_ucodepoint_t) (val))

#define DUK_RAW_READ_U8(ptr) ((duk_uint8_t) (*(ptr)))
#define DUK_RAW_READ_U16_BE(ptr) duk_raw_read_u16_be((ptr));
#define DUK_RAW_READ_U32_BE(ptr) duk_raw_read_u32_be((ptr));
#define DUK_RAW_READ_DOUBLE_BE(ptr) duk_raw_read_double_be((ptr));

#define DUK_RAW_READINC_U8(ptr) ((duk_uint8_t) (*(ptr)++))
#define DUK_RAW_READINC_U16_BE(ptr) duk_raw_readinc_u16_be(&(ptr));
#define DUK_RAW_READINC_U32_BE(ptr) duk_raw_readinc_u32_be(&(ptr));
#define DUK_RAW_READINC_DOUBLE_BE(ptr) duk_raw_readinc_double_be(&(ptr));

/*
 *  Double and float byte order operations.
 */

DUK_INTERNAL_DECL void duk_dblunion_host_to_little(duk_double_union *u);
DUK_INTERNAL_DECL void duk_dblunion_little_to_host(duk_double_union *u);
DUK_INTERNAL_DECL void duk_dblunion_host_to_big(duk_double_union *u);
DUK_INTERNAL_DECL void duk_dblunion_big_to_host(duk_double_union *u);
DUK_INTERNAL_DECL void duk_fltunion_host_to_big(duk_float_union *u);
DUK_INTERNAL_DECL void duk_fltunion_big_to_host(duk_float_union *u);

/*
 *  Buffer writer (dynamic buffer only)
 *
 *  Helper for writing to a dynamic buffer with a concept of a "slack" area
 *  to reduce resizes.  You can ensure there is enough space beforehand and
 *  then write for a while without further checks, relying on a stable data
 *  pointer.  Slack handling is automatic so call sites only indicate how
 *  much data they need right now.
 *
 *  There are several ways to write using bufwriter.  The best approach
 *  depends mainly on how much performance matters over code footprint.
 *  The key issues are (1) ensuring there is space and (2) keeping the
 *  pointers consistent.  Fast code should ensure space for multiple writes
 *  with one ensure call.  Fastest inner loop code can temporarily borrow
 *  the 'p' pointer but must write it back eventually.
 *
 *  Be careful to ensure all macro arguments (other than static pointers like
 *  'thr' and 'bw_ctx') are evaluated exactly once, using temporaries if
 *  necessary (if that's not possible, there should be a note near the macro).
 *  Buffer write arguments often contain arithmetic etc so this is
 *  particularly important here.
 */

/* XXX: Migrate bufwriter and other read/write helpers to its own header? */

struct duk_bufwriter_ctx {
	duk_uint8_t *p;
	duk_uint8_t *p_base;
	duk_uint8_t *p_limit;
	duk_hbuffer_dynamic *buf;
};

#if defined(DUK_USE_PREFER_SIZE)
#define DUK_BW_SLACK_ADD           64
#define DUK_BW_SLACK_SHIFT         4    /* 2^4 -> 1/16 = 6.25% slack */
#else
#define DUK_BW_SLACK_ADD           64
#define DUK_BW_SLACK_SHIFT         2    /* 2^2 -> 1/4 = 25% slack */
#endif

/* Initialization and finalization (compaction), converting to other types. */

#define DUK_BW_INIT_PUSHBUF(thr,bw_ctx,sz) do { \
		duk_bw_init_pushbuf((thr), (bw_ctx), (sz)); \
	} while (0)
#define DUK_BW_INIT_WITHBUF(thr,bw_ctx,buf) do { \
		duk_bw_init((thr), (bw_ctx), (buf)); \
	} while (0)
#define DUK_BW_COMPACT(thr,bw_ctx) do { \
		/* Make underlying buffer compact to match DUK_BW_GET_SIZE(). */ \
		duk_bw_compact((thr), (bw_ctx)); \
	} while (0)
#define DUK_BW_PUSH_AS_STRING(thr,bw_ctx) do { \
		duk_push_lstring((thr), \
		                 (const char *) (bw_ctx)->p_base, \
		                 (duk_size_t) ((bw_ctx)->p - (bw_ctx)->p_base)); \
	} while (0)

/* Pointers may be NULL for a while when 'buf' size is zero and before any
 * ENSURE calls have been made.  Once an ENSURE has been made, the pointers
 * are required to be non-NULL so that it's always valid to use memcpy() and
 * memmove(), even for zero size.
 */
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_bw_assert_valid(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx);
#define DUK_BW_ASSERT_VALID_EXPR(thr,bw_ctx)  (duk_bw_assert_valid((thr), (bw_ctx)))
#define DUK_BW_ASSERT_VALID(thr,bw_ctx)  do { duk_bw_assert_valid((thr), (bw_ctx)); } while (0)
#else
#define DUK_BW_ASSERT_VALID_EXPR(thr,bw_ctx)  DUK_ASSERT_EXPR(1)
#define DUK_BW_ASSERT_VALID(thr,bw_ctx)  do {} while (0)
#endif

/* Working with the pointer and current size. */

#define DUK_BW_GET_PTR(thr,bw_ctx) \
	((bw_ctx)->p)
#define DUK_BW_SET_PTR(thr,bw_ctx,ptr) do { \
		(bw_ctx)->p = (ptr); \
	} while (0)
#define DUK_BW_ADD_PTR(thr,bw_ctx,delta) do { \
		(bw_ctx)->p += (delta); \
	} while (0)
#define DUK_BW_GET_BASEPTR(thr,bw_ctx) \
	((bw_ctx)->p_base)
#define DUK_BW_GET_LIMITPTR(thr,bw_ctx) \
	((bw_ctx)->p_limit)
#define DUK_BW_GET_SIZE(thr,bw_ctx) \
	((duk_size_t) ((bw_ctx)->p - (bw_ctx)->p_base))
#define DUK_BW_SET_SIZE(thr,bw_ctx,sz) do { \
		DUK_ASSERT((duk_size_t) (sz) <= (duk_size_t) ((bw_ctx)->p - (bw_ctx)->p_base)); \
		(bw_ctx)->p = (bw_ctx)->p_base + (sz); \
	} while (0)
#define DUK_BW_RESET_SIZE(thr,bw_ctx) do { \
		/* Reset to zero size, keep current limit. */ \
		(bw_ctx)->p = (bw_ctx)->p_base; \
	} while (0)
#define DUK_BW_GET_BUFFER(thr,bw_ctx) \
	((bw_ctx)->buf)

/* Ensuring (reserving) space. */

#define DUK_BW_ENSURE(thr,bw_ctx,sz) do { \
		duk_size_t duk__sz, duk__space; \
		DUK_BW_ASSERT_VALID((thr), (bw_ctx)); \
		duk__sz = (sz); \
		duk__space = (duk_size_t) ((bw_ctx)->p_limit - (bw_ctx)->p); \
		if (duk__space < duk__sz) { \
			(void) duk_bw_resize((thr), (bw_ctx), duk__sz); \
		} \
	} while (0)
/* NOTE: Multiple evaluation of 'ptr' in this macro. */
/* XXX: Rework to use an always-inline function? */
#define DUK_BW_ENSURE_RAW(thr,bw_ctx,sz,ptr) \
	(((duk_size_t) ((bw_ctx)->p_limit - (ptr)) >= (sz)) ? \
	 (ptr) : \
	 ((bw_ctx)->p = (ptr), duk_bw_resize((thr),(bw_ctx),(sz))))
#define DUK_BW_ENSURE_GETPTR(thr,bw_ctx,sz) \
	DUK_BW_ENSURE_RAW((thr), (bw_ctx), (sz), (bw_ctx)->p)
#define DUK_BW_ASSERT_SPACE_EXPR(thr,bw_ctx,sz) \
	(DUK_BW_ASSERT_VALID_EXPR((thr), (bw_ctx)), \
	 DUK_ASSERT_EXPR((duk_size_t) ((bw_ctx)->p_limit - (bw_ctx)->p) >= (duk_size_t) (sz)))
#define DUK_BW_ASSERT_SPACE(thr,bw_ctx,sz) do { \
		DUK_BW_ASSERT_SPACE_EXPR((thr), (bw_ctx), (sz)); \
	} while (0)

/* Miscellaneous. */

#define DUK_BW_SETPTR_AND_COMPACT(thr,bw_ctx,ptr) do { \
		(bw_ctx)->p = (ptr); \
		duk_bw_compact((thr), (bw_ctx)); \
	} while (0)

/* Fast write calls which assume you control the slack beforehand.
 * Multibyte write variants exist and use a temporary write pointer
 * because byte writes alias with anything: with a stored pointer
 * explicit pointer load/stores get generated (e.g. gcc -Os).
 */

#define DUK_BW_WRITE_RAW_U8(thr,bw_ctx,val) do { \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 1); \
		*(bw_ctx)->p++ = (duk_uint8_t) (val); \
	} while (0)
#define DUK_BW_WRITE_RAW_U8_2(thr,bw_ctx,val1,val2) do { \
		duk_uint8_t *duk__p; \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 2); \
		duk__p = (bw_ctx)->p; \
		*duk__p++ = (duk_uint8_t) (val1); \
		*duk__p++ = (duk_uint8_t) (val2); \
		(bw_ctx)->p = duk__p; \
	} while (0)
#define DUK_BW_WRITE_RAW_U8_3(thr,bw_ctx,val1,val2,val3) do { \
		duk_uint8_t *duk__p; \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 3); \
		duk__p = (bw_ctx)->p; \
		*duk__p++ = (duk_uint8_t) (val1); \
		*duk__p++ = (duk_uint8_t) (val2); \
		*duk__p++ = (duk_uint8_t) (val3); \
		(bw_ctx)->p = duk__p; \
	} while (0)
#define DUK_BW_WRITE_RAW_U8_4(thr,bw_ctx,val1,val2,val3,val4) do { \
		duk_uint8_t *duk__p; \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 4); \
		duk__p = (bw_ctx)->p; \
		*duk__p++ = (duk_uint8_t) (val1); \
		*duk__p++ = (duk_uint8_t) (val2); \
		*duk__p++ = (duk_uint8_t) (val3); \
		*duk__p++ = (duk_uint8_t) (val4); \
		(bw_ctx)->p = duk__p; \
	} while (0)
#define DUK_BW_WRITE_RAW_U8_5(thr,bw_ctx,val1,val2,val3,val4,val5) do { \
		duk_uint8_t *duk__p; \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 5); \
		duk__p = (bw_ctx)->p; \
		*duk__p++ = (duk_uint8_t) (val1); \
		*duk__p++ = (duk_uint8_t) (val2); \
		*duk__p++ = (duk_uint8_t) (val3); \
		*duk__p++ = (duk_uint8_t) (val4); \
		*duk__p++ = (duk_uint8_t) (val5); \
		(bw_ctx)->p = duk__p; \
	} while (0)
#define DUK_BW_WRITE_RAW_U8_6(thr,bw_ctx,val1,val2,val3,val4,val5,val6) do { \
		duk_uint8_t *duk__p; \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), 6); \
		duk__p = (bw_ctx)->p; \
		*duk__p++ = (duk_uint8_t) (val1); \
		*duk__p++ = (duk_uint8_t) (val2); \
		*duk__p++ = (duk_uint8_t) (val3); \
		*duk__p++ = (duk_uint8_t) (val4); \
		*duk__p++ = (duk_uint8_t) (val5); \
		*duk__p++ = (duk_uint8_t) (val6); \
		(bw_ctx)->p = duk__p; \
	} while (0)
#define DUK_BW_WRITE_RAW_XUTF8(thr,bw_ctx,cp) do { \
		duk_ucodepoint_t duk__cp; \
		duk_small_int_t duk__enc_len; \
		duk__cp = (duk_ucodepoint_t) (cp); \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), duk_unicode_get_xutf8_length(duk__cp)); \
		duk__enc_len = duk_unicode_encode_xutf8(duk__cp, (bw_ctx)->p); \
		(bw_ctx)->p += duk__enc_len; \
	} while (0)
#define DUK_BW_WRITE_RAW_CESU8(thr,bw_ctx,cp) do { \
		duk_ucodepoint_t duk__cp; \
		duk_small_int_t duk__enc_len; \
		duk__cp = (duk_ucodepoint_t) (cp); \
		DUK_BW_ASSERT_SPACE((thr), (bw_ctx), duk_unicode_get_cesu8_length(duk__cp)); \
		duk__enc_len = duk_unicode_encode_cesu8(duk__cp, (bw_ctx)->p); \
		(bw_ctx)->p += duk__enc_len; \
	} while (0)
/* XXX: add temporary duk__p pointer here too; sharing */
/* XXX: avoid unsafe variants */
#define DUK_BW_WRITE_RAW_BYTES(thr,bw_ctx,valptr,valsz) do { \
		const void *duk__valptr; \
		duk_size_t duk__valsz; \
		duk__valptr = (const void *) (valptr); \
		duk__valsz = (duk_size_t) (valsz); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), duk__valptr, duk__valsz); \
		(bw_ctx)->p += duk__valsz; \
	} while (0)
#define DUK_BW_WRITE_RAW_CSTRING(thr,bw_ctx,val) do { \
		const duk_uint8_t *duk__val; \
		duk_size_t duk__val_len; \
		duk__val = (const duk_uint8_t *) (val); \
		duk__val_len = DUK_STRLEN((const char *) duk__val); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) duk__val, duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_RAW_HSTRING(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HSTRING_GET_BYTELEN((val)); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HSTRING_GET_DATA((val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_RAW_HBUFFER(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_GET_SIZE((val)); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_RAW_HBUFFER_FIXED(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_FIXED_GET_SIZE((val)); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_FIXED_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_RAW_HBUFFER_DYNAMIC(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_DYNAMIC_GET_SIZE((val)); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)

/* Append bytes from a slice already in the buffer. */
#define DUK_BW_WRITE_RAW_SLICE(thr,bw,dst_off,dst_len) \
	duk_bw_write_raw_slice((thr), (bw), (dst_off), (dst_len))

/* Insert bytes in the middle of the buffer from an external buffer. */
#define DUK_BW_INSERT_RAW_BYTES(thr,bw,dst_off,buf,len) \
	duk_bw_insert_raw_bytes((thr), (bw), (dst_off), (buf), (len))

/* Insert bytes in the middle of the buffer from a slice already
 * in the buffer.  Source offset is interpreted "before" the operation.
 */
#define DUK_BW_INSERT_RAW_SLICE(thr,bw,dst_off,src_off,len) \
	duk_bw_insert_raw_slice((thr), (bw), (dst_off), (src_off), (len))

/* Insert a reserved area somewhere in the buffer; caller fills it.
 * Evaluates to a (duk_uint_t *) pointing to the start of the reserved
 * area for convenience.
 */
#define DUK_BW_INSERT_RAW_AREA(thr,bw,off,len) \
	duk_bw_insert_raw_area((thr), (bw), (off), (len))

/* Remove a slice from inside buffer. */
#define DUK_BW_REMOVE_RAW_SLICE(thr,bw,off,len) \
	duk_bw_remove_raw_slice((thr), (bw), (off), (len))

/* Safe write calls which will ensure space first. */

#define DUK_BW_WRITE_ENSURE_U8(thr,bw_ctx,val) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 1); \
		DUK_BW_WRITE_RAW_U8((thr), (bw_ctx), (val)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_U8_2(thr,bw_ctx,val1,val2) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 2); \
		DUK_BW_WRITE_RAW_U8_2((thr), (bw_ctx), (val1), (val2)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_U8_3(thr,bw_ctx,val1,val2,val3) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 3); \
		DUK_BW_WRITE_RAW_U8_3((thr), (bw_ctx), (val1), (val2), (val3)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_U8_4(thr,bw_ctx,val1,val2,val3,val4) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 4); \
		DUK_BW_WRITE_RAW_U8_4((thr), (bw_ctx), (val1), (val2), (val3), (val4)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_U8_5(thr,bw_ctx,val1,val2,val3,val4,val5) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 5); \
		DUK_BW_WRITE_RAW_U8_5((thr), (bw_ctx), (val1), (val2), (val3), (val4), (val5)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_U8_6(thr,bw_ctx,val1,val2,val3,val4,val5,val6) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), 6); \
		DUK_BW_WRITE_RAW_U8_6((thr), (bw_ctx), (val1), (val2), (val3), (val4), (val5), (val6)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_XUTF8(thr,bw_ctx,cp) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), DUK_UNICODE_MAX_XUTF8_LENGTH); \
		DUK_BW_WRITE_RAW_XUTF8((thr), (bw_ctx), (cp)); \
	} while (0)
#define DUK_BW_WRITE_ENSURE_CESU8(thr,bw_ctx,cp) do { \
		DUK_BW_ENSURE((thr), (bw_ctx), DUK_UNICODE_MAX_CESU8_LENGTH); \
		DUK_BW_WRITE_RAW_CESU8((thr), (bw_ctx), (cp)); \
	} while (0)
/* XXX: add temporary duk__p pointer here too; sharing */
/* XXX: avoid unsafe */
#define DUK_BW_WRITE_ENSURE_BYTES(thr,bw_ctx,valptr,valsz) do { \
		const void *duk__valptr; \
		duk_size_t duk__valsz; \
		duk__valptr = (const void *) (valptr); \
		duk__valsz = (duk_size_t) (valsz); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__valsz); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), duk__valptr, duk__valsz); \
		(bw_ctx)->p += duk__valsz; \
	} while (0)
#define DUK_BW_WRITE_ENSURE_CSTRING(thr,bw_ctx,val) do { \
		const duk_uint8_t *duk__val; \
		duk_size_t duk__val_len; \
		duk__val = (const duk_uint8_t *) (val); \
		duk__val_len = DUK_STRLEN((const char *) duk__val); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__val_len); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) duk__val, duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_ENSURE_HSTRING(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HSTRING_GET_BYTELEN((val)); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__val_len); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HSTRING_GET_DATA((val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_ENSURE_HBUFFER(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_GET_SIZE((val)); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__val_len); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_ENSURE_HBUFFER_FIXED(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_FIXED_GET_SIZE((val)); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__val_len); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_FIXED_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)
#define DUK_BW_WRITE_ENSURE_HBUFFER_DYNAMIC(thr,bw_ctx,val) do { \
		duk_size_t duk__val_len; \
		duk__val_len = DUK_HBUFFER_DYNAMIC_GET_SIZE((val)); \
		DUK_BW_ENSURE((thr), (bw_ctx), duk__val_len); \
		duk_memcpy_unsafe((void *) ((bw_ctx)->p), (const void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR((thr)->heap, (val)), duk__val_len); \
		(bw_ctx)->p += duk__val_len; \
	} while (0)

#define DUK_BW_WRITE_ENSURE_SLICE(thr,bw,dst_off,dst_len) \
	duk_bw_write_ensure_slice((thr), (bw), (dst_off), (dst_len))
#define DUK_BW_INSERT_ENSURE_BYTES(thr,bw,dst_off,buf,len) \
	duk_bw_insert_ensure_bytes((thr), (bw), (dst_off), (buf), (len))
#define DUK_BW_INSERT_ENSURE_SLICE(thr,bw,dst_off,src_off,len) \
	duk_bw_insert_ensure_slice((thr), (bw), (dst_off), (src_off), (len))
#define DUK_BW_INSERT_ENSURE_AREA(thr,bw,off,len) \
	/* Evaluates to (duk_uint8_t *) pointing to start of area. */ \
	duk_bw_insert_ensure_area((thr), (bw), (off), (len))
#define DUK_BW_REMOVE_ENSURE_SLICE(thr,bw,off,len) \
	/* No difference between raw/ensure because the buffer shrinks. */ \
	DUK_BW_REMOVE_RAW_SLICE((thr), (bw), (off), (len))

/*
 *  Externs and prototypes
 */

#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_lc_digits[36];
DUK_INTERNAL_DECL const duk_uint8_t duk_uc_nybbles[16];
DUK_INTERNAL_DECL const duk_int8_t duk_hex_dectab[256];
#if defined(DUK_USE_HEX_FASTPATH)
DUK_INTERNAL_DECL const duk_int16_t duk_hex_dectab_shift4[256];
DUK_INTERNAL_DECL const duk_uint16_t duk_hex_enctab[256];
#endif
#endif  /* !DUK_SINGLE_FILE */

/* Note: assumes that duk_util_probe_steps size is 32 */
#if defined(DUK_USE_HOBJECT_HASH_PART)
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL duk_uint8_t duk_util_probe_steps[32];
#endif  /* !DUK_SINGLE_FILE */
#endif

#if defined(DUK_USE_STRHASH_DENSE)
DUK_INTERNAL_DECL duk_uint32_t duk_util_hashbytes(const duk_uint8_t *data, duk_size_t len, duk_uint32_t seed);
#endif

DUK_INTERNAL_DECL duk_uint32_t duk_bd_decode(duk_bitdecoder_ctx *ctx, duk_small_int_t bits);
DUK_INTERNAL_DECL duk_small_uint_t duk_bd_decode_flag(duk_bitdecoder_ctx *ctx);
DUK_INTERNAL_DECL duk_uint32_t duk_bd_decode_flagged(duk_bitdecoder_ctx *ctx, duk_small_int_t bits, duk_uint32_t def_value);
DUK_INTERNAL_DECL duk_int32_t duk_bd_decode_flagged_signed(duk_bitdecoder_ctx *ctx, duk_small_int_t bits, duk_int32_t def_value);
DUK_INTERNAL_DECL duk_uint32_t duk_bd_decode_varuint(duk_bitdecoder_ctx *ctx);
DUK_INTERNAL_DECL duk_small_uint_t duk_bd_decode_bitpacked_string(duk_bitdecoder_ctx *bd, duk_uint8_t *out);

DUK_INTERNAL_DECL void duk_be_encode(duk_bitencoder_ctx *ctx, duk_uint32_t data, duk_small_int_t bits);
DUK_INTERNAL_DECL void duk_be_finish(duk_bitencoder_ctx *ctx);

#if !defined(DUK_USE_GET_RANDOM_DOUBLE)
DUK_INTERNAL_DECL duk_double_t duk_util_tinyrandom_get_double(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_util_tinyrandom_prepare_seed(duk_hthread *thr);
#endif

DUK_INTERNAL_DECL void duk_bw_init(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_hbuffer_dynamic *h_buf);
DUK_INTERNAL_DECL void duk_bw_init_pushbuf(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_size_t buf_size);
DUK_INTERNAL_DECL duk_uint8_t *duk_bw_resize(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_size_t sz);
DUK_INTERNAL_DECL void duk_bw_compact(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx);
DUK_INTERNAL_DECL void duk_bw_write_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t src_off, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_write_ensure_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t src_off, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_insert_raw_bytes(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, const duk_uint8_t *buf, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_insert_ensure_bytes(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, const duk_uint8_t *buf, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_insert_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, duk_size_t src_off, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_insert_ensure_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, duk_size_t src_off, duk_size_t len);
DUK_INTERNAL_DECL duk_uint8_t *duk_bw_insert_raw_area(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len);
DUK_INTERNAL_DECL duk_uint8_t *duk_bw_insert_ensure_area(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len);
DUK_INTERNAL_DECL void duk_bw_remove_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len);
/* No duk_bw_remove_ensure_slice(), functionality would be identical. */

DUK_INTERNAL_DECL duk_uint16_t duk_raw_read_u16_be(const duk_uint8_t *p);
DUK_INTERNAL_DECL duk_uint32_t duk_raw_read_u32_be(const duk_uint8_t *p);
DUK_INTERNAL_DECL duk_float_t duk_raw_read_float_be(const duk_uint8_t *p);
DUK_INTERNAL_DECL duk_double_t duk_raw_read_double_be(const duk_uint8_t *p);
DUK_INTERNAL_DECL duk_uint16_t duk_raw_readinc_u16_be(const duk_uint8_t **p);
DUK_INTERNAL_DECL duk_uint32_t duk_raw_readinc_u32_be(const duk_uint8_t **p);
DUK_INTERNAL_DECL duk_float_t duk_raw_readinc_float_be(const duk_uint8_t **p);
DUK_INTERNAL_DECL duk_double_t duk_raw_readinc_double_be(const duk_uint8_t **p);
DUK_INTERNAL_DECL void duk_raw_write_u16_be(duk_uint8_t *p, duk_uint16_t val);
DUK_INTERNAL_DECL void duk_raw_write_u32_be(duk_uint8_t *p, duk_uint32_t val);
DUK_INTERNAL_DECL void duk_raw_write_float_be(duk_uint8_t *p, duk_float_t val);
DUK_INTERNAL_DECL void duk_raw_write_double_be(duk_uint8_t *p, duk_double_t val);
DUK_INTERNAL_DECL duk_small_int_t duk_raw_write_xutf8(duk_uint8_t *p, duk_ucodepoint_t val);
DUK_INTERNAL_DECL duk_small_int_t duk_raw_write_cesu8(duk_uint8_t *p, duk_ucodepoint_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_u16_be(duk_uint8_t **p, duk_uint16_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_u32_be(duk_uint8_t **p, duk_uint32_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_float_be(duk_uint8_t **p, duk_float_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_double_be(duk_uint8_t **p, duk_double_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_xutf8(duk_uint8_t **p, duk_ucodepoint_t val);
DUK_INTERNAL_DECL void duk_raw_writeinc_cesu8(duk_uint8_t **p, duk_ucodepoint_t val);

#if defined(DUK_USE_DEBUGGER_SUPPORT)  /* For now only needed by the debugger. */
DUK_INTERNAL_DECL void duk_byteswap_bytes(duk_uint8_t *p, duk_small_uint_t len);
#endif

/* memcpy(), memmove() etc wrappers.  The plain variants like duk_memcpy()
 * assume C99+ and 'src' and 'dst' pointers must be non-NULL even when the
 * operation size is zero.  The unsafe variants like duk_memcpy_safe() deal
 * with the zero size case explicitly, and allow NULL pointers in that case
 * (which is undefined behavior in C99+).  For the majority of actual targets
 * a NULL pointer with a zero length is fine in practice.  These wrappers are
 * macros to force inlining; because there are hundreds of call sites, even a
 * few extra bytes per call site adds up to ~1kB footprint.
 */
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
#define duk_memcpy(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		DUK_ASSERT(duk__src != NULL || duk__len == 0U); \
		(void) DUK_MEMCPY(duk__dst, duk__src, (size_t) duk__len); \
	} while (0)
#define duk_memcpy_unsafe(dst,src,len)  duk_memcpy((dst), (src), (len))
#define duk_memmove(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		DUK_ASSERT(duk__src != NULL || duk__len == 0U); \
		(void) DUK_MEMMOVE(duk__dst, duk__src, (size_t) duk__len); \
	} while (0)
#define duk_memmove_unsafe(dst,src,len)  duk_memmove((dst), (src), (len))
#define duk_memset(dst,val,len)  do { \
		void *duk__dst = (dst); \
		duk_small_int_t duk__val = (val); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		(void) DUK_MEMSET(duk__dst, duk__val, (size_t) duk__len); \
	} while (0)
#define duk_memset_unsafe(dst,val,len)  duk_memset((dst), (val), (len))
#define duk_memzero(dst,len)  do { \
		void *duk__dst = (dst); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		(void) DUK_MEMZERO(duk__dst, (size_t) duk__len); \
	} while (0)
#define duk_memzero_unsafe(dst,len)  duk_memzero((dst), (len))
#else  /* DUK_USE_ALLOW_UNDEFINED_BEHAVIOR */
#define duk_memcpy(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL); \
		DUK_ASSERT(duk__src != NULL); \
		(void) DUK_MEMCPY(duk__dst, duk__src, (size_t) duk__len); \
	} while (0)
#define duk_memcpy_unsafe(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		DUK_ASSERT(duk__src != NULL || duk__len == 0U); \
		if (DUK_LIKELY(duk__len > 0U)) { \
			DUK_ASSERT(duk__dst != NULL); \
			DUK_ASSERT(duk__src != NULL); \
			(void) DUK_MEMCPY(duk__dst, duk__src, (size_t) duk__len); \
		} \
	} while (0)
#define duk_memmove(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL); \
		DUK_ASSERT(duk__src != NULL); \
		(void) DUK_MEMMOVE(duk__dst, duk__src, (size_t) duk__len); \
	} while (0)
#define duk_memmove_unsafe(dst,src,len)  do { \
		void *duk__dst = (dst); \
		const void *duk__src = (src); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		DUK_ASSERT(duk__src != NULL || duk__len == 0U); \
		if (DUK_LIKELY(duk__len > 0U)) { \
			DUK_ASSERT(duk__dst != NULL); \
			DUK_ASSERT(duk__src != NULL); \
			(void) DUK_MEMMOVE(duk__dst, duk__src, (size_t) duk__len); \
		} \
	} while (0)
#define duk_memset(dst,val,len)  do { \
		void *duk__dst = (dst); \
		duk_small_int_t duk__val = (val); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL); \
		(void) DUK_MEMSET(duk__dst, duk__val, (size_t) duk__len); \
	} while (0)
#define duk_memset_unsafe(dst,val,len)  do { \
		void *duk__dst = (dst); \
		duk_small_int_t duk__val = (val); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		if (DUK_LIKELY(duk__len > 0U)) { \
			DUK_ASSERT(duk__dst != NULL); \
			(void) DUK_MEMSET(duk__dst, duk__val, (size_t) duk__len); \
		} \
	} while (0)
#define duk_memzero(dst,len)  do { \
		void *duk__dst = (dst); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL); \
		(void) DUK_MEMZERO(duk__dst, (size_t) duk__len); \
	} while (0)
#define duk_memzero_unsafe(dst,len)  do { \
		void *duk__dst = (dst); \
		duk_size_t duk__len = (len); \
		DUK_ASSERT(duk__dst != NULL || duk__len == 0U); \
		if (DUK_LIKELY(duk__len > 0U)) { \
			DUK_ASSERT(duk__dst != NULL); \
			(void) DUK_MEMZERO(duk__dst, (size_t) duk__len); \
		} \
	} while (0)
#endif  /* DUK_USE_ALLOW_UNDEFINED_BEHAVIOR */

DUK_INTERNAL_DECL duk_small_int_t duk_memcmp(const void *s1, const void *s2, duk_size_t len);
DUK_INTERNAL_DECL duk_small_int_t duk_memcmp_unsafe(const void *s1, const void *s2, duk_size_t len);

DUK_INTERNAL_DECL duk_bool_t duk_is_whole_get_int32_nonegzero(duk_double_t x, duk_int32_t *ival);
DUK_INTERNAL_DECL duk_bool_t duk_is_whole_get_int32(duk_double_t x, duk_int32_t *ival);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_anyinf(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_posinf(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_neginf(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_nan(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_nan_or_zero(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_nan_or_inf(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_nan_zero_inf(duk_double_t x);
DUK_INTERNAL_DECL duk_small_uint_t duk_double_signbit(duk_double_t x);
DUK_INTERNAL_DECL duk_double_t duk_double_trunc_towards_zero(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_same_sign(duk_double_t x, duk_double_t y);
DUK_INTERNAL_DECL duk_double_t duk_double_fmin(duk_double_t x, duk_double_t y);
DUK_INTERNAL_DECL duk_double_t duk_double_fmax(duk_double_t x, duk_double_t y);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_finite(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_integer(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_is_safe_integer(duk_double_t x);

DUK_INTERNAL_DECL duk_double_t duk_double_div(duk_double_t x, duk_double_t y);
DUK_INTERNAL_DECL duk_int_t duk_double_to_int_t(duk_double_t x);
DUK_INTERNAL_DECL duk_uint_t duk_double_to_uint_t(duk_double_t x);
DUK_INTERNAL_DECL duk_int32_t duk_double_to_int32_t(duk_double_t x);
DUK_INTERNAL_DECL duk_uint32_t duk_double_to_uint32_t(duk_double_t x);
DUK_INTERNAL_DECL duk_float_t duk_double_to_float_t(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_double_equals(duk_double_t x, duk_double_t y);
DUK_INTERNAL_DECL duk_bool_t duk_float_equals(duk_float_t x, duk_float_t y);

/*
 *  Miscellaneous
 */

/* Example: x     = 0x10 = 0b00010000
 *          x - 1 = 0x0f = 0b00001111
 *          x & (x - 1) == 0
 *
 *          x     = 0x07 = 0b00000111
 *          x - 1 = 0x06 = 0b00000110
 *          x & (x - 1) != 0
 *
 * However, incorrectly true for x == 0 so check for that explicitly.
 */
#define DUK_IS_POWER_OF_TWO(x) \
	((x) != 0U && ((x) & ((x) - 1U)) == 0U)

#endif  /* DUK_UTIL_H_INCLUDED */
/* #include duk_strings.h */
/*
 *  Shared string macros.
 *
 *  Using shared macros helps minimize strings data size because it's easy
 *  to check if an existing string could be used.  String constants don't
 *  need to be all defined here; defining a string here makes sense if there's
 *  a high chance the string could be reused.  Also, using macros allows
 *  a call site express the exact string needed, but the macro may map to an
 *  approximate string to reduce unique string count.  Macros can also be
 *  more easily tuned for low memory targets than #if defined()s throughout
 *  the code base.
 *
 *  Because format strings behave differently in the call site (they need to
 *  be followed by format arguments), they use a special prefix DUK_STR_FMT_.
 *
 *  On some compilers using explicit shared strings is preferable; on others
 *  it may be better to use straight literals because the compiler will combine
 *  them anyway, and such strings won't end up unnecessarily in a symbol table.
 */

#if !defined(DUK_ERRMSG_H_INCLUDED)
#define DUK_ERRMSG_H_INCLUDED

/* Mostly API and built-in method related */
#define DUK_STR_INTERNAL_ERROR                   "internal error"
#define DUK_STR_UNSUPPORTED                      "unsupported"
#define DUK_STR_INVALID_COUNT                    "invalid count"
#define DUK_STR_INVALID_ARGS                     "invalid args"
#define DUK_STR_INVALID_STATE                    "invalid state"
#define DUK_STR_INVALID_INPUT                    "invalid input"
#define DUK_STR_INVALID_LENGTH                   "invalid length"
#define DUK_STR_NOT_CONSTRUCTABLE                "not constructable"
#define DUK_STR_CONSTRUCT_ONLY                   "constructor requires 'new'"
#define DUK_STR_NOT_CALLABLE                     "not callable"
#define DUK_STR_NOT_EXTENSIBLE                   "not extensible"
#define DUK_STR_NOT_WRITABLE                     "not writable"
#define DUK_STR_NOT_CONFIGURABLE                 "not configurable"
#define DUK_STR_INVALID_CONTEXT                  "invalid context"
#define DUK_STR_INVALID_INDEX                    "invalid args"
#define DUK_STR_PUSH_BEYOND_ALLOC_STACK          "cannot push beyond allocated stack"
#define DUK_STR_NOT_UNDEFINED                    "unexpected type"
#define DUK_STR_NOT_NULL                         "unexpected type"
#define DUK_STR_NOT_BOOLEAN                      "unexpected type"
#define DUK_STR_NOT_NUMBER                       "unexpected type"
#define DUK_STR_NOT_STRING                       "unexpected type"
#define DUK_STR_NOT_OBJECT                       "unexpected type"
#define DUK_STR_NOT_POINTER                      "unexpected type"
#define DUK_STR_NOT_BUFFER                       "not buffer"  /* still in use with verbose messages */
#define DUK_STR_UNEXPECTED_TYPE                  "unexpected type"
#define DUK_STR_NOT_THREAD                       "unexpected type"
#define DUK_STR_NOT_COMPFUNC                     "unexpected type"
#define DUK_STR_NOT_NATFUNC                      "unexpected type"
#define DUK_STR_NOT_C_FUNCTION                   "unexpected type"
#define DUK_STR_NOT_FUNCTION                     "unexpected type"
#define DUK_STR_NOT_REGEXP                       "unexpected type"
#define DUK_STR_TOPRIMITIVE_FAILED               "coercion to primitive failed"
#define DUK_STR_NUMBER_OUTSIDE_RANGE             "number outside range"
#define DUK_STR_NOT_OBJECT_COERCIBLE             "not object coercible"
#define DUK_STR_CANNOT_NUMBER_COERCE_SYMBOL      "cannot number coerce Symbol"
#define DUK_STR_CANNOT_STRING_COERCE_SYMBOL      "cannot string coerce Symbol"
#define DUK_STR_STRING_TOO_LONG                  "string too long"
#define DUK_STR_BUFFER_TOO_LONG                  "buffer too long"
#define DUK_STR_ALLOC_FAILED                     "alloc failed"
#define DUK_STR_WRONG_BUFFER_TYPE                "wrong buffer type"
#define DUK_STR_BASE64_ENCODE_FAILED             "base64 encode failed"
#define DUK_STR_SOURCE_DECODE_FAILED             "source decode failed"
#define DUK_STR_UTF8_DECODE_FAILED               "utf-8 decode failed"
#define DUK_STR_BASE64_DECODE_FAILED             "base64 decode failed"
#define DUK_STR_HEX_DECODE_FAILED                "hex decode failed"
#define DUK_STR_INVALID_BYTECODE                 "invalid bytecode"
#define DUK_STR_NO_SOURCECODE                    "no sourcecode"
#define DUK_STR_RESULT_TOO_LONG                  "result too long"
#define DUK_STR_INVALID_CFUNC_RC                 "invalid C function rc"
#define DUK_STR_INVALID_INSTANCEOF_RVAL          "invalid instanceof rval"
#define DUK_STR_INVALID_INSTANCEOF_RVAL_NOPROTO  "instanceof rval has no .prototype"

/* JSON */
#define DUK_STR_FMT_PTR                          "%p"
#define DUK_STR_FMT_INVALID_JSON                 "invalid json (at offset %ld)"
#define DUK_STR_JSONDEC_RECLIMIT                 "json decode recursion limit"
#define DUK_STR_JSONENC_RECLIMIT                 "json encode recursion limit"
#define DUK_STR_CYCLIC_INPUT                     "cyclic input"

/* Object property access */
#define DUK_STR_INVALID_BASE                     "invalid base value"
#define DUK_STR_STRICT_CALLER_READ               "cannot read strict 'caller'"
#define DUK_STR_PROXY_REJECTED                   "proxy rejected"
#define DUK_STR_INVALID_ARRAY_LENGTH             "invalid array length"
#define DUK_STR_SETTER_UNDEFINED                 "setter undefined"
#define DUK_STR_INVALID_DESCRIPTOR               "invalid descriptor"

/* Proxy */
#define DUK_STR_PROXY_REVOKED                    "proxy revoked"
#define DUK_STR_INVALID_TRAP_RESULT              "invalid trap result"

/* Variables */

/* Lexer */
#define DUK_STR_INVALID_ESCAPE                   "invalid escape"
#define DUK_STR_UNTERMINATED_STRING              "unterminated string"
#define DUK_STR_UNTERMINATED_COMMENT             "unterminated comment"
#define DUK_STR_UNTERMINATED_REGEXP              "unterminated regexp"
#define DUK_STR_TOKEN_LIMIT                      "token limit"
#define DUK_STR_REGEXP_SUPPORT_DISABLED          "regexp support disabled"
#define DUK_STR_INVALID_NUMBER_LITERAL           "invalid number literal"
#define DUK_STR_INVALID_TOKEN                    "invalid token"

/* Compiler */
#define DUK_STR_PARSE_ERROR                      "parse error"
#define DUK_STR_DUPLICATE_LABEL                  "duplicate label"
#define DUK_STR_INVALID_LABEL                    "invalid label"
#define DUK_STR_INVALID_ARRAY_LITERAL            "invalid array literal"
#define DUK_STR_INVALID_OBJECT_LITERAL           "invalid object literal"
#define DUK_STR_INVALID_VAR_DECLARATION          "invalid variable declaration"
#define DUK_STR_CANNOT_DELETE_IDENTIFIER         "cannot delete identifier"
#define DUK_STR_INVALID_EXPRESSION               "invalid expression"
#define DUK_STR_INVALID_LVALUE                   "invalid lvalue"
#define DUK_STR_INVALID_NEWTARGET                "invalid new.target"
#define DUK_STR_EXPECTED_IDENTIFIER              "expected identifier"
#define DUK_STR_EMPTY_EXPR_NOT_ALLOWED           "empty expression not allowed"
#define DUK_STR_INVALID_FOR                      "invalid for statement"
#define DUK_STR_INVALID_SWITCH                   "invalid switch statement"
#define DUK_STR_INVALID_BREAK_CONT_LABEL         "invalid break/continue label"
#define DUK_STR_INVALID_RETURN                   "invalid return"
#define DUK_STR_INVALID_TRY                      "invalid try"
#define DUK_STR_INVALID_THROW                    "invalid throw"
#define DUK_STR_WITH_IN_STRICT_MODE              "with in strict mode"
#define DUK_STR_FUNC_STMT_NOT_ALLOWED            "function statement not allowed"
#define DUK_STR_UNTERMINATED_STMT                "unterminated statement"
#define DUK_STR_INVALID_ARG_NAME                 "invalid argument name"
#define DUK_STR_INVALID_FUNC_NAME                "invalid function name"
#define DUK_STR_INVALID_GETSET_NAME              "invalid getter/setter name"
#define DUK_STR_FUNC_NAME_REQUIRED               "function name required"

/* RegExp */
#define DUK_STR_INVALID_QUANTIFIER               "invalid regexp quantifier"
#define DUK_STR_INVALID_QUANTIFIER_NO_ATOM       "quantifier without preceding atom"
#define DUK_STR_INVALID_QUANTIFIER_VALUES        "quantifier values invalid (qmin > qmax)"
#define DUK_STR_QUANTIFIER_TOO_MANY_COPIES       "quantifier requires too many atom copies"
#define DUK_STR_UNEXPECTED_CLOSING_PAREN         "unexpected closing parenthesis"
#define DUK_STR_UNEXPECTED_END_OF_PATTERN        "unexpected end of pattern"
#define DUK_STR_UNEXPECTED_REGEXP_TOKEN          "unexpected token in regexp"
#define DUK_STR_INVALID_REGEXP_FLAGS             "invalid regexp flags"
#define DUK_STR_INVALID_REGEXP_ESCAPE            "invalid regexp escape"
#define DUK_STR_INVALID_BACKREFS                 "invalid backreference(s)"
#define DUK_STR_INVALID_REGEXP_CHARACTER         "invalid regexp character"
#define DUK_STR_INVALID_REGEXP_GROUP             "invalid regexp group"
#define DUK_STR_UNTERMINATED_CHARCLASS           "unterminated character class"
#define DUK_STR_INVALID_RANGE                    "invalid range"

/* Limits */
#define DUK_STR_VALSTACK_LIMIT                   "valstack limit"
#define DUK_STR_CALLSTACK_LIMIT                  "callstack limit"
#define DUK_STR_PROTOTYPE_CHAIN_LIMIT            "prototype chain limit"
#define DUK_STR_BOUND_CHAIN_LIMIT                "function call bound chain limit"
#define DUK_STR_NATIVE_STACK_LIMIT               "C stack depth limit"
#define DUK_STR_COMPILER_RECURSION_LIMIT         "compiler recursion limit"
#define DUK_STR_BYTECODE_LIMIT                   "bytecode limit"
#define DUK_STR_REG_LIMIT                        "register limit"
#define DUK_STR_TEMP_LIMIT                       "temp limit"
#define DUK_STR_CONST_LIMIT                      "const limit"
#define DUK_STR_FUNC_LIMIT                       "function limit"
#define DUK_STR_REGEXP_COMPILER_RECURSION_LIMIT  "regexp compiler recursion limit"
#define DUK_STR_REGEXP_EXECUTOR_RECURSION_LIMIT  "regexp executor recursion limit"
#define DUK_STR_REGEXP_EXECUTOR_STEP_LIMIT       "regexp step limit"

#endif  /* DUK_ERRMSG_H_INCLUDED */
/* #include duk_js_bytecode.h */
/*
 *  ECMAScript bytecode
 */

#if !defined(DUK_JS_BYTECODE_H_INCLUDED)
#define DUK_JS_BYTECODE_H_INCLUDED

/*
 *  Bytecode instruction layout
 *  ===========================
 *
 *  Instructions are unsigned 32-bit integers divided as follows:
 *
 *  !3!3!2!2!2!2!2!2!2!2!2!2!1!1!1!1!1!1!1!1!1!1! ! ! ! ! ! ! ! ! ! !
 *  !1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!
 *  +-----------------------------------------------+---------------+
 *  !       C       !       B       !       A       !       OP      !
 *  +-----------------------------------------------+---------------+
 *
 *  OP (8 bits):  opcode (DUK_OP_*), access should be fastest
 *                consecutive opcodes allocated when opcode needs flags
 *   A (8 bits):  typically a target register number
 *   B (8 bits):  typically first source register/constant number
 *   C (8 bits):  typically second source register/constant number
 *
 *  Some instructions combine BC or ABC together for larger parameter values.
 *  Signed integers (e.g. jump offsets) are encoded as unsigned, with an
 *  opcode specific bias.
 *
 *  Some opcodes have flags which are handled by allocating consecutive
 *  opcodes to make space for 1-N flags.  Flags can also be e.g. in the 'A'
 *  field when there's room for the specific opcode.
 *
 *  For example, if three flags were needed, they could be allocated from
 *  the opcode field as follows:
 *
 *  !3!3!2!2!2!2!2!2!2!2!2!2!1!1!1!1!1!1!1!1!1!1! ! ! ! ! ! ! ! ! ! !
 *  !1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!
 *  +-----------------------------------------------+---------------+
 *  !       C       !       B       !       A       !    OP   !Z!Y!X!
 *  +-----------------------------------------------+---------------+
 *
 *  Some opcodes accept a reg/const argument which is handled by allocating
 *  flags in the OP field, see DUK_BC_ISREG() and DUK_BC_ISCONST().  The
 *  following convention is shared by most opcodes, so that the compiler
 *  can handle reg/const flagging without opcode specific code paths:
 *
 *  !3!3!2!2!2!2!2!2!2!2!2!2!1!1!1!1!1!1!1!1!1!1! ! ! ! ! ! ! ! ! ! !
 *  !1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!9!8!7!6!5!4!3!2!1!0!
 *  +-----------------------------------------------+---------------+
 *  !       C       !       B       !       A       !     OP    !Y!X!
 *  +-----------------------------------------------+---------------+
 *
 *    X  1=B is const, 0=B is reg
 *    Y  1=C is const, 0=C is reg
 *
 *    In effect OP, OP + 1, OP + 2, and OP + 3 are allocated from the
 *    8-bit opcode space for a single logical opcode.  The base opcode
 *    number should be divisible by 4.  If the opcode is called 'FOO'
 *    the following opcode constants would be defined:
 *
 *      DUK_OP_FOO     100       // base opcode number
 *      DUK_OP_FOO_RR  100       // FOO, B=reg, C=reg
 *      DUK_OP_FOO_CR  101       // FOO, B=const, C=reg
 *      DUK_OP_FOO_RC  102       // FOO, B=reg, C=const
 *      DUK_OP_FOO_CC  103       // FOO, B=const, C=const
 *
 *  If only B or C is a reg/const, the unused opcode combinations can be
 *  used for other opcodes (which take no reg/const argument).  However,
 *  such opcode values are initially reserved, at least while opcode space
 *  is available.  For example, if 'BAR' uses B for a register field and
 *  C is a reg/const:
 *
 *      DUK_OP_BAR            116    // base opcode number
 *      DUK_OP_BAR_RR         116    // BAR, B=reg, C=reg
 *      DUK_OP_BAR_CR_UNUSED  117    // unused, could be repurposed
 *      DUK_OP_BAR_RC         118    // BAR, B=reg, C=const
 *      DUK_OP_BAR_CC_UNUSED  119    // unused, could be repurposed
 *
 *  Macro naming is a bit misleading, e.g. "ABC" in macro name but the
 *  field layout is concretely "CBA" in the register.
 */

typedef duk_uint32_t duk_instr_t;

#define DUK_BC_SHIFT_OP             0
#define DUK_BC_SHIFT_A              8
#define DUK_BC_SHIFT_B              16
#define DUK_BC_SHIFT_C              24
#define DUK_BC_SHIFT_BC             DUK_BC_SHIFT_B
#define DUK_BC_SHIFT_ABC            DUK_BC_SHIFT_A

#define DUK_BC_UNSHIFTED_MASK_OP    0xffUL
#define DUK_BC_UNSHIFTED_MASK_A     0xffUL
#define DUK_BC_UNSHIFTED_MASK_B     0xffUL
#define DUK_BC_UNSHIFTED_MASK_C     0xffUL
#define DUK_BC_UNSHIFTED_MASK_BC    0xffffUL
#define DUK_BC_UNSHIFTED_MASK_ABC   0xffffffUL

#define DUK_BC_SHIFTED_MASK_OP      (DUK_BC_UNSHIFTED_MASK_OP << DUK_BC_SHIFT_OP)
#define DUK_BC_SHIFTED_MASK_A       (DUK_BC_UNSHIFTED_MASK_A << DUK_BC_SHIFT_A)
#define DUK_BC_SHIFTED_MASK_B       (DUK_BC_UNSHIFTED_MASK_B << DUK_BC_SHIFT_B)
#define DUK_BC_SHIFTED_MASK_C       (DUK_BC_UNSHIFTED_MASK_C << DUK_BC_SHIFT_C)
#define DUK_BC_SHIFTED_MASK_BC      (DUK_BC_UNSHIFTED_MASK_BC << DUK_BC_SHIFT_BC)
#define DUK_BC_SHIFTED_MASK_ABC     (DUK_BC_UNSHIFTED_MASK_ABC << DUK_BC_SHIFT_ABC)

#define DUK_DEC_OP(x)               ((x) & 0xffUL)
#define DUK_DEC_A(x)                (((x) >> 8) & 0xffUL)
#define DUK_DEC_B(x)                (((x) >> 16) & 0xffUL)
#define DUK_DEC_C(x)                (((x) >> 24) & 0xffUL)
#define DUK_DEC_BC(x)               (((x) >> 16) & 0xffffUL)
#define DUK_DEC_ABC(x)              (((x) >> 8) & 0xffffffUL)

#define DUK_ENC_OP(op)              ((duk_instr_t) (op))
#define DUK_ENC_OP_ABC(op,abc)      ((duk_instr_t) ( \
                                        (((duk_instr_t) (abc)) << 8) | \
                                        ((duk_instr_t) (op)) \
                                    ))
#define DUK_ENC_OP_A_BC(op,a,bc)    ((duk_instr_t) ( \
                                        (((duk_instr_t) (bc)) << 16) | \
                                        (((duk_instr_t) (a)) << 8) | \
                                        ((duk_instr_t) (op)) \
                                    ))
#define DUK_ENC_OP_A_B_C(op,a,b,c)  ((duk_instr_t) ( \
                                        (((duk_instr_t) (c)) << 24) | \
                                        (((duk_instr_t) (b)) << 16) | \
                                        (((duk_instr_t) (a)) << 8) | \
                                        ((duk_instr_t) (op)) \
                                    ))
#define DUK_ENC_OP_A_B(op,a,b)      DUK_ENC_OP_A_B_C((op),(a),(b),0)
#define DUK_ENC_OP_A(op,a)          DUK_ENC_OP_A_B_C((op),(a),0,0)
#define DUK_ENC_OP_BC(op,bc)        DUK_ENC_OP_A_BC((op),0,(bc))

/* Get opcode base value with B/C reg/const flags cleared. */
#define DUK_BC_NOREGCONST_OP(op)    ((op) & 0xfc)

/* Constants should be signed so that signed arithmetic involving them
 * won't cause values to be coerced accidentally to unsigned.
 */
#define DUK_BC_OP_MIN               0
#define DUK_BC_OP_MAX               0xffL
#define DUK_BC_A_MIN                0
#define DUK_BC_A_MAX                0xffL
#define DUK_BC_B_MIN                0
#define DUK_BC_B_MAX                0xffL
#define DUK_BC_C_MIN                0
#define DUK_BC_C_MAX                0xffL
#define DUK_BC_BC_MIN               0
#define DUK_BC_BC_MAX               0xffffL
#define DUK_BC_ABC_MIN              0
#define DUK_BC_ABC_MAX              0xffffffL

/* Masks for B/C reg/const indicator in opcode field. */
#define DUK_BC_REGCONST_B           (0x01UL)
#define DUK_BC_REGCONST_C           (0x02UL)

/* Misc. masks for opcode field. */
#define DUK_BC_INCDECP_FLAG_DEC     (0x04UL)
#define DUK_BC_INCDECP_FLAG_POST    (0x08UL)

/* Opcodes. */
#define DUK_OP_LDREG                0
#define DUK_OP_STREG                1
#define DUK_OP_JUMP                 2
#define DUK_OP_LDCONST              3
#define DUK_OP_LDINT                4
#define DUK_OP_LDINTX               5
#define DUK_OP_LDTHIS               6
#define DUK_OP_LDUNDEF              7
#define DUK_OP_LDNULL               8
#define DUK_OP_LDTRUE               9
#define DUK_OP_LDFALSE              10
#define DUK_OP_GETVAR               11
#define DUK_OP_BNOT                 12
#define DUK_OP_LNOT                 13
#define DUK_OP_UNM                  14
#define DUK_OP_UNP                  15
#define DUK_OP_EQ                   16
#define DUK_OP_EQ_RR                16
#define DUK_OP_EQ_CR                17
#define DUK_OP_EQ_RC                18
#define DUK_OP_EQ_CC                19
#define DUK_OP_NEQ                  20
#define DUK_OP_NEQ_RR               20
#define DUK_OP_NEQ_CR               21
#define DUK_OP_NEQ_RC               22
#define DUK_OP_NEQ_CC               23
#define DUK_OP_SEQ                  24
#define DUK_OP_SEQ_RR               24
#define DUK_OP_SEQ_CR               25
#define DUK_OP_SEQ_RC               26
#define DUK_OP_SEQ_CC               27
#define DUK_OP_SNEQ                 28
#define DUK_OP_SNEQ_RR              28
#define DUK_OP_SNEQ_CR              29
#define DUK_OP_SNEQ_RC              30
#define DUK_OP_SNEQ_CC              31
#define DUK_OP_GT                   32
#define DUK_OP_GT_RR                32
#define DUK_OP_GT_CR                33
#define DUK_OP_GT_RC                34
#define DUK_OP_GT_CC                35
#define DUK_OP_GE                   36
#define DUK_OP_GE_RR                36
#define DUK_OP_GE_CR                37
#define DUK_OP_GE_RC                38
#define DUK_OP_GE_CC                39
#define DUK_OP_LT                   40
#define DUK_OP_LT_RR                40
#define DUK_OP_LT_CR                41
#define DUK_OP_LT_RC                42
#define DUK_OP_LT_CC                43
#define DUK_OP_LE                   44
#define DUK_OP_LE_RR                44
#define DUK_OP_LE_CR                45
#define DUK_OP_LE_RC                46
#define DUK_OP_LE_CC                47
#define DUK_OP_IFTRUE               48
#define DUK_OP_IFTRUE_R             48
#define DUK_OP_IFTRUE_C             49
#define DUK_OP_IFFALSE              50
#define DUK_OP_IFFALSE_R            50
#define DUK_OP_IFFALSE_C            51
#define DUK_OP_ADD                  52
#define DUK_OP_ADD_RR               52
#define DUK_OP_ADD_CR               53
#define DUK_OP_ADD_RC               54
#define DUK_OP_ADD_CC               55
#define DUK_OP_SUB                  56
#define DUK_OP_SUB_RR               56
#define DUK_OP_SUB_CR               57
#define DUK_OP_SUB_RC               58
#define DUK_OP_SUB_CC               59
#define DUK_OP_MUL                  60
#define DUK_OP_MUL_RR               60
#define DUK_OP_MUL_CR               61
#define DUK_OP_MUL_RC               62
#define DUK_OP_MUL_CC               63
#define DUK_OP_DIV                  64
#define DUK_OP_DIV_RR               64
#define DUK_OP_DIV_CR               65
#define DUK_OP_DIV_RC               66
#define DUK_OP_DIV_CC               67
#define DUK_OP_MOD                  68
#define DUK_OP_MOD_RR               68
#define DUK_OP_MOD_CR               69
#define DUK_OP_MOD_RC               70
#define DUK_OP_MOD_CC               71
#define DUK_OP_EXP                  72
#define DUK_OP_EXP_RR               72
#define DUK_OP_EXP_CR               73
#define DUK_OP_EXP_RC               74
#define DUK_OP_EXP_CC               75
#define DUK_OP_BAND                 76
#define DUK_OP_BAND_RR              76
#define DUK_OP_BAND_CR              77
#define DUK_OP_BAND_RC              78
#define DUK_OP_BAND_CC              79
#define DUK_OP_BOR                  80
#define DUK_OP_BOR_RR               80
#define DUK_OP_BOR_CR               81
#define DUK_OP_BOR_RC               82
#define DUK_OP_BOR_CC               83
#define DUK_OP_BXOR                 84
#define DUK_OP_BXOR_RR              84
#define DUK_OP_BXOR_CR              85
#define DUK_OP_BXOR_RC              86
#define DUK_OP_BXOR_CC              87
#define DUK_OP_BASL                 88
#define DUK_OP_BASL_RR              88
#define DUK_OP_BASL_CR              89
#define DUK_OP_BASL_RC              90
#define DUK_OP_BASL_CC              91
#define DUK_OP_BLSR                 92
#define DUK_OP_BLSR_RR              92
#define DUK_OP_BLSR_CR              93
#define DUK_OP_BLSR_RC              94
#define DUK_OP_BLSR_CC              95
#define DUK_OP_BASR                 96
#define DUK_OP_BASR_RR              96
#define DUK_OP_BASR_CR              97
#define DUK_OP_BASR_RC              98
#define DUK_OP_BASR_CC              99
#define DUK_OP_INSTOF               100
#define DUK_OP_INSTOF_RR            100
#define DUK_OP_INSTOF_CR            101
#define DUK_OP_INSTOF_RC            102
#define DUK_OP_INSTOF_CC            103
#define DUK_OP_IN                   104
#define DUK_OP_IN_RR                104
#define DUK_OP_IN_CR                105
#define DUK_OP_IN_RC                106
#define DUK_OP_IN_CC                107
#define DUK_OP_GETPROP              108
#define DUK_OP_GETPROP_RR           108
#define DUK_OP_GETPROP_CR           109
#define DUK_OP_GETPROP_RC           110
#define DUK_OP_GETPROP_CC           111
#define DUK_OP_PUTPROP              112
#define DUK_OP_PUTPROP_RR           112
#define DUK_OP_PUTPROP_CR           113
#define DUK_OP_PUTPROP_RC           114
#define DUK_OP_PUTPROP_CC           115
#define DUK_OP_DELPROP              116
#define DUK_OP_DELPROP_RR           116
#define DUK_OP_DELPROP_CR_UNUSED    117  /* unused now */
#define DUK_OP_DELPROP_RC           118
#define DUK_OP_DELPROP_CC_UNUSED    119  /* unused now */
#define DUK_OP_PREINCR              120  /* pre/post opcode values have constraints, */
#define DUK_OP_PREDECR              121  /* see duk_js_executor.c and duk_js_compiler.c. */
#define DUK_OP_POSTINCR             122
#define DUK_OP_POSTDECR             123
#define DUK_OP_PREINCV              124
#define DUK_OP_PREDECV              125
#define DUK_OP_POSTINCV             126
#define DUK_OP_POSTDECV             127
#define DUK_OP_PREINCP              128  /* pre/post inc/dec prop opcodes have constraints */
#define DUK_OP_PREINCP_RR           128
#define DUK_OP_PREINCP_CR           129
#define DUK_OP_PREINCP_RC           130
#define DUK_OP_PREINCP_CC           131
#define DUK_OP_PREDECP              132
#define DUK_OP_PREDECP_RR           132
#define DUK_OP_PREDECP_CR           133
#define DUK_OP_PREDECP_RC           134
#define DUK_OP_PREDECP_CC           135
#define DUK_OP_POSTINCP             136
#define DUK_OP_POSTINCP_RR          136
#define DUK_OP_POSTINCP_CR          137
#define DUK_OP_POSTINCP_RC          138
#define DUK_OP_POSTINCP_CC          139
#define DUK_OP_POSTDECP             140
#define DUK_OP_POSTDECP_RR          140
#define DUK_OP_POSTDECP_CR          141
#define DUK_OP_POSTDECP_RC          142
#define DUK_OP_POSTDECP_CC          143
#define DUK_OP_DECLVAR              144
#define DUK_OP_DECLVAR_RR           144
#define DUK_OP_DECLVAR_CR           145
#define DUK_OP_DECLVAR_RC           146
#define DUK_OP_DECLVAR_CC           147
#define DUK_OP_REGEXP               148
#define DUK_OP_REGEXP_RR            148
#define DUK_OP_REGEXP_CR            149
#define DUK_OP_REGEXP_RC            150
#define DUK_OP_REGEXP_CC            151
#define DUK_OP_CLOSURE              152
#define DUK_OP_TYPEOF               153
#define DUK_OP_TYPEOFID             154
#define DUK_OP_PUTVAR               155
#define DUK_OP_DELVAR               156
#define DUK_OP_RETREG               157
#define DUK_OP_RETUNDEF             158
#define DUK_OP_RETCONST             159
#define DUK_OP_RETCONSTN            160  /* return const without incref (e.g. number) */
#define DUK_OP_LABEL                161
#define DUK_OP_ENDLABEL             162
#define DUK_OP_BREAK                163
#define DUK_OP_CONTINUE             164
#define DUK_OP_TRYCATCH             165
#define DUK_OP_ENDTRY               166
#define DUK_OP_ENDCATCH             167
#define DUK_OP_ENDFIN               168
#define DUK_OP_THROW                169
#define DUK_OP_INVLHS               170
#define DUK_OP_CSREG                171
#define DUK_OP_CSVAR                172
#define DUK_OP_CSVAR_RR             172
#define DUK_OP_CSVAR_CR             173
#define DUK_OP_CSVAR_RC             174
#define DUK_OP_CSVAR_CC             175
#define DUK_OP_CALL0                176  /* DUK_OP_CALL0 & 0x0F must be zero. */
#define DUK_OP_CALL1                177
#define DUK_OP_CALL2                178
#define DUK_OP_CALL3                179
#define DUK_OP_CALL4                180
#define DUK_OP_CALL5                181
#define DUK_OP_CALL6                182
#define DUK_OP_CALL7                183
#define DUK_OP_CALL8                184
#define DUK_OP_CALL9                185
#define DUK_OP_CALL10               186
#define DUK_OP_CALL11               187
#define DUK_OP_CALL12               188
#define DUK_OP_CALL13               189
#define DUK_OP_CALL14               190
#define DUK_OP_CALL15               191
#define DUK_OP_NEWOBJ               192
#define DUK_OP_NEWARR               193
#define DUK_OP_MPUTOBJ              194
#define DUK_OP_MPUTOBJI             195
#define DUK_OP_INITSET              196
#define DUK_OP_INITGET              197
#define DUK_OP_MPUTARR              198
#define DUK_OP_MPUTARRI             199
#define DUK_OP_SETALEN              200
#define DUK_OP_INITENUM             201
#define DUK_OP_NEXTENUM             202
#define DUK_OP_NEWTARGET            203
#define DUK_OP_DEBUGGER             204
#define DUK_OP_NOP                  205
#define DUK_OP_INVALID              206
#define DUK_OP_UNUSED207            207
#define DUK_OP_GETPROPC             208
#define DUK_OP_GETPROPC_RR          208
#define DUK_OP_GETPROPC_CR          209
#define DUK_OP_GETPROPC_RC          210
#define DUK_OP_GETPROPC_CC          211
#define DUK_OP_UNUSED212            212
#define DUK_OP_UNUSED213            213
#define DUK_OP_UNUSED214            214
#define DUK_OP_UNUSED215            215
#define DUK_OP_UNUSED216            216
#define DUK_OP_UNUSED217            217
#define DUK_OP_UNUSED218            218
#define DUK_OP_UNUSED219            219
#define DUK_OP_UNUSED220            220
#define DUK_OP_UNUSED221            221
#define DUK_OP_UNUSED222            222
#define DUK_OP_UNUSED223            223
#define DUK_OP_UNUSED224            224
#define DUK_OP_UNUSED225            225
#define DUK_OP_UNUSED226            226
#define DUK_OP_UNUSED227            227
#define DUK_OP_UNUSED228            228
#define DUK_OP_UNUSED229            229
#define DUK_OP_UNUSED230            230
#define DUK_OP_UNUSED231            231
#define DUK_OP_UNUSED232            232
#define DUK_OP_UNUSED233            233
#define DUK_OP_UNUSED234            234
#define DUK_OP_UNUSED235            235
#define DUK_OP_UNUSED236            236
#define DUK_OP_UNUSED237            237
#define DUK_OP_UNUSED238            238
#define DUK_OP_UNUSED239            239
#define DUK_OP_UNUSED240            240
#define DUK_OP_UNUSED241            241
#define DUK_OP_UNUSED242            242
#define DUK_OP_UNUSED243            243
#define DUK_OP_UNUSED244            244
#define DUK_OP_UNUSED245            245
#define DUK_OP_UNUSED246            246
#define DUK_OP_UNUSED247            247
#define DUK_OP_UNUSED248            248
#define DUK_OP_UNUSED249            249
#define DUK_OP_UNUSED250            250
#define DUK_OP_UNUSED251            251
#define DUK_OP_UNUSED252            252
#define DUK_OP_UNUSED253            253
#define DUK_OP_UNUSED254            254
#define DUK_OP_UNUSED255            255
#define DUK_OP_NONE                 256  /* dummy value used as marker (doesn't fit in 8-bit field) */

/* XXX: Allocate flags from opcode field?  Would take 16 opcode slots
 * but avoids shuffling in more cases.  Maybe not worth it.
 */
/* DUK_OP_TRYCATCH flags in A. */
#define DUK_BC_TRYCATCH_FLAG_HAVE_CATCH     (1U << 0)
#define DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY   (1U << 1)
#define DUK_BC_TRYCATCH_FLAG_CATCH_BINDING  (1U << 2)
#define DUK_BC_TRYCATCH_FLAG_WITH_BINDING   (1U << 3)

/* DUK_OP_DECLVAR flags in A; bottom bits are reserved for propdesc flags
 * (DUK_PROPDESC_FLAG_XXX).
 */
#define DUK_BC_DECLVAR_FLAG_FUNC_DECL       (1U << 4)  /* function declaration */

/* DUK_OP_CALLn flags, part of opcode field.  Three lowest bits must match
 * DUK_CALL_FLAG_xxx directly.
 */
#define DUK_BC_CALL_FLAG_TAILCALL           (1U << 0)
#define DUK_BC_CALL_FLAG_CONSTRUCT          (1U << 1)
#define DUK_BC_CALL_FLAG_CALLED_AS_EVAL     (1U << 2)
#define DUK_BC_CALL_FLAG_INDIRECT           (1U << 3)

/* Misc constants and helper macros. */
#define DUK_BC_LDINT_BIAS           (1L << 15)
#define DUK_BC_LDINTX_SHIFT         16
#define DUK_BC_JUMP_BIAS            (1L << 23)

#endif  /* DUK_JS_BYTECODE_H_INCLUDED */
/* #include duk_lexer.h */
/*
 *  Lexer defines.
 */

#if !defined(DUK_LEXER_H_INCLUDED)
#define DUK_LEXER_H_INCLUDED

typedef void (*duk_re_range_callback)(void *user, duk_codepoint_t r1, duk_codepoint_t r2, duk_bool_t direct);

/*
 *  A token is interpreted as any possible production of InputElementDiv
 *  and InputElementRegExp, see E5 Section 7 in its entirety.  Note that
 *  the E5 "Token" production does not cover all actual tokens of the
 *  language (which is explicitly stated in the specification, Section 7.5).
 *  Null and boolean literals are defined as part of both ReservedWord
 *  (E5 Section 7.6.1) and Literal (E5 Section 7.8) productions.  Here,
 *  null and boolean values have literal tokens, and are not reserved
 *  words.
 *
 *  Decimal literal negative/positive sign is -not- part of DUK_TOK_NUMBER.
 *  The number tokens always have a non-negative value.  The unary minus
 *  operator in "-1.0" is optimized during compilation to yield a single
 *  negative constant.
 *
 *  Token numbering is free except that reserved words are required to be
 *  in a continuous range and in a particular order.  See genstrings.py.
 */

#define DUK_LEXER_INITCTX(ctx)        duk_lexer_initctx((ctx))

#define DUK_LEXER_SETPOINT(ctx,pt)    duk_lexer_setpoint((ctx), (pt))

#define DUK_LEXER_GETPOINT(ctx,pt)    duk_lexer_getpoint((ctx), (pt))

/* Currently 6 characters of lookup are actually needed (duk_lexer.c). */
#define DUK_LEXER_WINDOW_SIZE                     6
#if defined(DUK_USE_LEXER_SLIDING_WINDOW)
#define DUK_LEXER_BUFFER_SIZE                     64
#endif

#define DUK_TOK_MINVAL                            0

/* returned after EOF (infinite amount) */
#define DUK_TOK_EOF                               0

/* identifier names (E5 Section 7.6) */
#define DUK_TOK_IDENTIFIER                        1

/* reserved words: keywords */
#define DUK_TOK_START_RESERVED                    2
#define DUK_TOK_BREAK                             2
#define DUK_TOK_CASE                              3
#define DUK_TOK_CATCH                             4
#define DUK_TOK_CONTINUE                          5
#define DUK_TOK_DEBUGGER                          6
#define DUK_TOK_DEFAULT                           7
#define DUK_TOK_DELETE                            8
#define DUK_TOK_DO                                9
#define DUK_TOK_ELSE                              10
#define DUK_TOK_FINALLY                           11
#define DUK_TOK_FOR                               12
#define DUK_TOK_FUNCTION                          13
#define DUK_TOK_IF                                14
#define DUK_TOK_IN                                15
#define DUK_TOK_INSTANCEOF                        16
#define DUK_TOK_NEW                               17
#define DUK_TOK_RETURN                            18
#define DUK_TOK_SWITCH                            19
#define DUK_TOK_THIS                              20
#define DUK_TOK_THROW                             21
#define DUK_TOK_TRY                               22
#define DUK_TOK_TYPEOF                            23
#define DUK_TOK_VAR                               24
#define DUK_TOK_CONST                             25
#define DUK_TOK_VOID                              26
#define DUK_TOK_WHILE                             27
#define DUK_TOK_WITH                              28

/* reserved words: future reserved words */
#define DUK_TOK_CLASS                             29
#define DUK_TOK_ENUM                              30
#define DUK_TOK_EXPORT                            31
#define DUK_TOK_EXTENDS                           32
#define DUK_TOK_IMPORT                            33
#define DUK_TOK_SUPER                             34

/* "null", "true", and "false" are always reserved words.
 * Note that "get" and "set" are not!
 */
#define DUK_TOK_NULL                              35
#define DUK_TOK_TRUE                              36
#define DUK_TOK_FALSE                             37

/* reserved words: additional future reserved words in strict mode */
#define DUK_TOK_START_STRICT_RESERVED             38  /* inclusive */
#define DUK_TOK_IMPLEMENTS                        38
#define DUK_TOK_INTERFACE                         39
#define DUK_TOK_LET                               40
#define DUK_TOK_PACKAGE                           41
#define DUK_TOK_PRIVATE                           42
#define DUK_TOK_PROTECTED                         43
#define DUK_TOK_PUBLIC                            44
#define DUK_TOK_STATIC                            45
#define DUK_TOK_YIELD                             46

#define DUK_TOK_END_RESERVED                      47  /* exclusive */

/* "get" and "set" are tokens but NOT ReservedWords.  They are currently
 * parsed and identifiers and these defines are actually now unused.
 */
#define DUK_TOK_GET                               47
#define DUK_TOK_SET                               48

/* punctuators (unlike the spec, also includes "/" and "/=") */
#define DUK_TOK_LCURLY                            49
#define DUK_TOK_RCURLY                            50
#define DUK_TOK_LBRACKET                          51
#define DUK_TOK_RBRACKET                          52
#define DUK_TOK_LPAREN                            53
#define DUK_TOK_RPAREN                            54
#define DUK_TOK_PERIOD                            55
#define DUK_TOK_SEMICOLON                         56
#define DUK_TOK_COMMA                             57
#define DUK_TOK_LT                                58
#define DUK_TOK_GT                                59
#define DUK_TOK_LE                                60
#define DUK_TOK_GE                                61
#define DUK_TOK_EQ                                62
#define DUK_TOK_NEQ                               63
#define DUK_TOK_SEQ                               64
#define DUK_TOK_SNEQ                              65
#define DUK_TOK_ADD                               66
#define DUK_TOK_SUB                               67
#define DUK_TOK_MUL                               68
#define DUK_TOK_DIV                               69
#define DUK_TOK_MOD                               70
#define DUK_TOK_EXP                               71
#define DUK_TOK_INCREMENT                         72
#define DUK_TOK_DECREMENT                         73
#define DUK_TOK_ALSHIFT                           74   /* named "arithmetic" because result is signed */
#define DUK_TOK_ARSHIFT                           75
#define DUK_TOK_RSHIFT                            76
#define DUK_TOK_BAND                              77
#define DUK_TOK_BOR                               78
#define DUK_TOK_BXOR                              79
#define DUK_TOK_LNOT                              80
#define DUK_TOK_BNOT                              81
#define DUK_TOK_LAND                              82
#define DUK_TOK_LOR                               83
#define DUK_TOK_QUESTION                          84
#define DUK_TOK_COLON                             85
#define DUK_TOK_EQUALSIGN                         86
#define DUK_TOK_ADD_EQ                            87
#define DUK_TOK_SUB_EQ                            88
#define DUK_TOK_MUL_EQ                            89
#define DUK_TOK_DIV_EQ                            90
#define DUK_TOK_MOD_EQ                            91
#define DUK_TOK_EXP_EQ                            92
#define DUK_TOK_ALSHIFT_EQ                        93
#define DUK_TOK_ARSHIFT_EQ                        94
#define DUK_TOK_RSHIFT_EQ                         95
#define DUK_TOK_BAND_EQ                           96
#define DUK_TOK_BOR_EQ                            97
#define DUK_TOK_BXOR_EQ                           98

/* literals (E5 Section 7.8), except null, true, false, which are treated
 * like reserved words (above).
 */
#define DUK_TOK_NUMBER                            99
#define DUK_TOK_STRING                            100
#define DUK_TOK_REGEXP                            101

#define DUK_TOK_MAXVAL                            101  /* inclusive */

#define DUK_TOK_INVALID                           DUK_SMALL_UINT_MAX

/* Convert heap string index to a token (reserved words) */
#define DUK_STRIDX_TO_TOK(x)                        ((x) - DUK_STRIDX_START_RESERVED + DUK_TOK_START_RESERVED)

/* Sanity check */
#if (DUK_TOK_MAXVAL > 255)
#error DUK_TOK_MAXVAL too large, code assumes it fits into 8 bits
#endif

/* Sanity checks for string and token defines */
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_BREAK) != DUK_TOK_BREAK)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_CASE) != DUK_TOK_CASE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_CATCH) != DUK_TOK_CATCH)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_CONTINUE) != DUK_TOK_CONTINUE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_DEBUGGER) != DUK_TOK_DEBUGGER)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_DEFAULT) != DUK_TOK_DEFAULT)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_DELETE) != DUK_TOK_DELETE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_DO) != DUK_TOK_DO)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_ELSE) != DUK_TOK_ELSE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_FINALLY) != DUK_TOK_FINALLY)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_FOR) != DUK_TOK_FOR)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_LC_FUNCTION) != DUK_TOK_FUNCTION)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_IF) != DUK_TOK_IF)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_IN) != DUK_TOK_IN)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_INSTANCEOF) != DUK_TOK_INSTANCEOF)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_NEW) != DUK_TOK_NEW)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_RETURN) != DUK_TOK_RETURN)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_SWITCH) != DUK_TOK_SWITCH)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_THIS) != DUK_TOK_THIS)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_THROW) != DUK_TOK_THROW)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_TRY) != DUK_TOK_TRY)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_TYPEOF) != DUK_TOK_TYPEOF)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_VAR) != DUK_TOK_VAR)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_VOID) != DUK_TOK_VOID)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_WHILE) != DUK_TOK_WHILE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_WITH) != DUK_TOK_WITH)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_CLASS) != DUK_TOK_CLASS)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_CONST) != DUK_TOK_CONST)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_ENUM) != DUK_TOK_ENUM)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_EXPORT) != DUK_TOK_EXPORT)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_EXTENDS) != DUK_TOK_EXTENDS)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_IMPORT) != DUK_TOK_IMPORT)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_SUPER) != DUK_TOK_SUPER)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_LC_NULL) != DUK_TOK_NULL)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_TRUE) != DUK_TOK_TRUE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_FALSE) != DUK_TOK_FALSE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_IMPLEMENTS) != DUK_TOK_IMPLEMENTS)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_INTERFACE) != DUK_TOK_INTERFACE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_LET) != DUK_TOK_LET)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_PACKAGE) != DUK_TOK_PACKAGE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_PRIVATE) != DUK_TOK_PRIVATE)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_PROTECTED) != DUK_TOK_PROTECTED)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_PUBLIC) != DUK_TOK_PUBLIC)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_STATIC) != DUK_TOK_STATIC)
#error mismatch in token defines
#endif
#if (DUK_STRIDX_TO_TOK(DUK_STRIDX_YIELD) != DUK_TOK_YIELD)
#error mismatch in token defines
#endif

/* Regexp tokens */
#define DUK_RETOK_EOF                              0
#define DUK_RETOK_DISJUNCTION                      1
#define DUK_RETOK_QUANTIFIER                       2
#define DUK_RETOK_ASSERT_START                     3
#define DUK_RETOK_ASSERT_END                       4
#define DUK_RETOK_ASSERT_WORD_BOUNDARY             5
#define DUK_RETOK_ASSERT_NOT_WORD_BOUNDARY         6
#define DUK_RETOK_ASSERT_START_POS_LOOKAHEAD       7
#define DUK_RETOK_ASSERT_START_NEG_LOOKAHEAD       8
#define DUK_RETOK_ATOM_PERIOD                      9
#define DUK_RETOK_ATOM_CHAR                        10
#define DUK_RETOK_ATOM_DIGIT                       11  /* assumptions in regexp compiler */
#define DUK_RETOK_ATOM_NOT_DIGIT                   12  /* -""- */
#define DUK_RETOK_ATOM_WHITE                       13  /* -""- */
#define DUK_RETOK_ATOM_NOT_WHITE                   14  /* -""- */
#define DUK_RETOK_ATOM_WORD_CHAR                   15  /* -""- */
#define DUK_RETOK_ATOM_NOT_WORD_CHAR               16  /* -""- */
#define DUK_RETOK_ATOM_BACKREFERENCE               17
#define DUK_RETOK_ATOM_START_CAPTURE_GROUP         18
#define DUK_RETOK_ATOM_START_NONCAPTURE_GROUP      19
#define DUK_RETOK_ATOM_START_CHARCLASS             20
#define DUK_RETOK_ATOM_START_CHARCLASS_INVERTED    21
#define DUK_RETOK_ATOM_END_GROUP                   22

/* Constants for duk_lexer_ctx.buf. */
#define DUK_LEXER_TEMP_BUF_LIMIT                   256

/* A token value.  Can be memcpy()'d, but note that slot1/slot2 values are on the valstack.
 * Some fields (like num, str1, str2) are only valid for specific token types and may have
 * stale values otherwise.
 */
struct duk_token {
	duk_small_uint_t t;           /* token type (with reserved word identification) */
	duk_small_uint_t t_nores;     /* token type (with reserved words as DUK_TOK_IDENTIFER) */
	duk_double_t num;             /* numeric value of token */
	duk_hstring *str1;            /* string 1 of token (borrowed, stored to ctx->slot1_idx) */
	duk_hstring *str2;            /* string 2 of token (borrowed, stored to ctx->slot2_idx) */
	duk_size_t start_offset;      /* start byte offset of token in lexer input */
	duk_int_t start_line;         /* start line of token (first char) */
	duk_int_t num_escapes;        /* number of escapes and line continuations (for directive prologue) */
	duk_bool_t lineterm;          /* token was preceded by a lineterm */
	duk_bool_t allow_auto_semi;   /* token allows automatic semicolon insertion (eof or preceded by newline) */
};

#define DUK_RE_QUANTIFIER_INFINITE         ((duk_uint32_t) 0xffffffffUL)

/* A regexp token value. */
struct duk_re_token {
	duk_small_uint_t t;          /* token type */
	duk_small_uint_t greedy;
	duk_uint32_t num;            /* numeric value (character, count) */
	duk_uint32_t qmin;
	duk_uint32_t qmax;
};

/* A structure for 'snapshotting' a point for rewinding */
struct duk_lexer_point {
	duk_size_t offset;
	duk_int_t line;
};

/* Lexer codepoint with additional info like offset/line number */
struct duk_lexer_codepoint {
	duk_codepoint_t codepoint;
	duk_size_t offset;
	duk_int_t line;
};

/* Lexer context.  Same context is used for ECMAScript and Regexp parsing. */
struct duk_lexer_ctx {
#if defined(DUK_USE_LEXER_SLIDING_WINDOW)
	duk_lexer_codepoint *window; /* unicode code points, window[0] is always next, points to 'buffer' */
	duk_lexer_codepoint buffer[DUK_LEXER_BUFFER_SIZE];
#else
	duk_lexer_codepoint window[DUK_LEXER_WINDOW_SIZE]; /* unicode code points, window[0] is always next */
#endif

	duk_hthread *thr;                              /* thread; minimizes argument passing */

	const duk_uint8_t *input;                      /* input string (may be a user pointer) */
	duk_size_t input_length;                       /* input byte length */
	duk_size_t input_offset;                       /* input offset for window leading edge (not window[0]) */
	duk_int_t input_line;                          /* input linenumber at input_offset (not window[0]), init to 1 */

	duk_idx_t slot1_idx;                           /* valstack slot for 1st token value */
	duk_idx_t slot2_idx;                           /* valstack slot for 2nd token value */
	duk_idx_t buf_idx;                             /* valstack slot for temp buffer */
	duk_hbuffer_dynamic *buf;                      /* temp accumulation buffer */
	duk_bufwriter_ctx bw;                          /* bufwriter for temp accumulation */

	duk_int_t token_count;                         /* number of tokens parsed */
	duk_int_t token_limit;                         /* maximum token count before error (sanity backstop) */

	duk_small_uint_t flags;                        /* lexer flags, use compiler flag defines for now */
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL void duk_lexer_initctx(duk_lexer_ctx *lex_ctx);

DUK_INTERNAL_DECL void duk_lexer_getpoint(duk_lexer_ctx *lex_ctx, duk_lexer_point *pt);
DUK_INTERNAL_DECL void duk_lexer_setpoint(duk_lexer_ctx *lex_ctx, duk_lexer_point *pt);

DUK_INTERNAL_DECL
void duk_lexer_parse_js_input_element(duk_lexer_ctx *lex_ctx,
                                      duk_token *out_token,
                                      duk_bool_t strict_mode,
                                      duk_bool_t regexp_mode);
#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_INTERNAL_DECL void duk_lexer_parse_re_token(duk_lexer_ctx *lex_ctx, duk_re_token *out_token);
DUK_INTERNAL_DECL void duk_lexer_parse_re_ranges(duk_lexer_ctx *lex_ctx, duk_re_range_callback gen_range, void *userdata);
#endif  /* DUK_USE_REGEXP_SUPPORT */

#endif  /* DUK_LEXER_H_INCLUDED */
/* #include duk_js_compiler.h */
/*
 *  ECMAScript compiler.
 */

#if !defined(DUK_JS_COMPILER_H_INCLUDED)
#define DUK_JS_COMPILER_H_INCLUDED

/* ECMAScript compiler limits */
#define DUK_COMPILER_TOKEN_LIMIT           100000000L  /* 1e8: protects against deeply nested inner functions */

/* maximum loopcount for peephole optimization */
#define DUK_COMPILER_PEEPHOLE_MAXITER      3

/* maximum bytecode length in instructions */
#define DUK_COMPILER_MAX_BYTECODE_LENGTH   (256L * 1024L * 1024L)  /* 1 GB */

/*
 *  Compiler intermediate values
 *
 *  Intermediate values describe either plain values (e.g. strings or
 *  numbers) or binary operations which have not yet been coerced into
 *  either a left-hand-side or right-hand-side role (e.g. object property).
 */

#define DUK_IVAL_NONE          0   /* no value */
#define DUK_IVAL_PLAIN         1   /* register, constant, or value */
#define DUK_IVAL_ARITH         2   /* binary arithmetic; DUK_OP_ADD, DUK_OP_EQ, other binary ops */
#define DUK_IVAL_PROP          3   /* property access */
#define DUK_IVAL_VAR           4   /* variable access */

#define DUK_ISPEC_NONE         0   /* no value */
#define DUK_ISPEC_VALUE        1   /* value resides in 'valstack_idx' */
#define DUK_ISPEC_REGCONST     2   /* value resides in a register or constant */

/* Bit mask which indicates that a regconst is a constant instead of a register.
 * Chosen so that when a regconst is cast to duk_int32_t, all consts are
 * negative values.
 */
#define DUK_REGCONST_CONST_MARKER    DUK_INT32_MIN  /* = -0x80000000 */

/* Type to represent a reg/const reference during compilation, with <0
 * indicating a constant.  Some call sites also use -1 to indicate 'none'.
 */
typedef duk_int32_t duk_regconst_t;

typedef struct {
	duk_small_uint_t t;          /* DUK_ISPEC_XXX */
	duk_regconst_t regconst;
	duk_idx_t valstack_idx;      /* always set; points to a reserved valstack slot */
} duk_ispec;

typedef struct {
	/*
	 *  PLAIN: x1
	 *  ARITH: x1 <op> x2
	 *  PROP: x1.x2
	 *  VAR: x1 (name)
	 */

	/* XXX: can be optimized for smaller footprint esp. on 32-bit environments */
	duk_small_uint_t t;          /* DUK_IVAL_XXX */
	duk_small_uint_t op;         /* bytecode opcode for binary ops */
	duk_ispec x1;
	duk_ispec x2;
} duk_ivalue;

/*
 *  Bytecode instruction representation during compilation
 *
 *  Contains the actual instruction and (optionally) debug info.
 */

struct duk_compiler_instr {
	duk_instr_t ins;
#if defined(DUK_USE_PC2LINE)
	duk_uint32_t line;
#endif
};

/*
 *  Compiler state
 */

#define DUK_LABEL_FLAG_ALLOW_BREAK       (1U << 0)
#define DUK_LABEL_FLAG_ALLOW_CONTINUE    (1U << 1)

#define DUK_DECL_TYPE_VAR                0
#define DUK_DECL_TYPE_FUNC               1

/* XXX: optimize to 16 bytes */
typedef struct {
	duk_small_uint_t flags;
	duk_int_t label_id;          /* numeric label_id (-1 reserved as marker) */
	duk_hstring *h_label;        /* borrowed label name */
	duk_int_t catch_depth;       /* catch depth at point of definition */
	duk_int_t pc_label;          /* pc of label statement:
	                              * pc+1: break jump site
	                              * pc+2: continue jump site
	                              */

	/* Fast jumps (which avoid longjmp) jump directly to the jump sites
	 * which are always known even while the iteration/switch statement
	 * is still being parsed.  A final peephole pass "straightens out"
	 * the jumps.
	 */
} duk_labelinfo;

/* Compiling state of one function, eventually converted to duk_hcompfunc */
struct duk_compiler_func {
	/* These pointers are at the start of the struct so that they pack
	 * nicely.  Mixing pointers and integer values is bad on some
	 * platforms (e.g. if int is 32 bits and pointers are 64 bits).
	 */

	duk_bufwriter_ctx bw_code;          /* bufwriter for code */

	duk_hstring *h_name;                /* function name (borrowed reference), ends up in _name */
	/* h_code: held in bw_code */
	duk_hobject *h_consts;              /* array */
	duk_hobject *h_funcs;               /* array of function templates: [func1, offset1, line1, func2, offset2, line2]
	                                     * offset/line points to closing brace to allow skipping on pass 2
	                                     */
	duk_hobject *h_decls;               /* array of declarations: [ name1, val1, name2, val2, ... ]
	                                     * valN = (typeN) | (fnum << 8), where fnum is inner func number (0 for vars)
	                                     * record function and variable declarations in pass 1
	                                     */
	duk_hobject *h_labelnames;          /* array of active label names */
	duk_hbuffer_dynamic *h_labelinfos;  /* C array of duk_labelinfo */
	duk_hobject *h_argnames;            /* array of formal argument names (-> _Formals) */
	duk_hobject *h_varmap;              /* variable map for pass 2 (identifier -> register number or null (unmapped)) */

	/* Value stack indices for tracking objects. */
	/* code_idx: not needed */
	duk_idx_t consts_idx;
	duk_idx_t funcs_idx;
	duk_idx_t decls_idx;
	duk_idx_t labelnames_idx;
	duk_idx_t labelinfos_idx;
	duk_idx_t argnames_idx;
	duk_idx_t varmap_idx;

	/* Temp reg handling. */
	duk_regconst_t temp_first;           /* first register that is a temporary (below: variables) */
	duk_regconst_t temp_next;            /* next temporary register to allocate */
	duk_regconst_t temp_max;             /* highest value of temp_reg (temp_max - 1 is highest used reg) */

	/* Shuffle registers if large number of regs/consts. */
	duk_regconst_t shuffle1;
	duk_regconst_t shuffle2;
	duk_regconst_t shuffle3;

	/* Stats for current expression being parsed. */
	duk_int_t nud_count;
	duk_int_t led_count;
	duk_int_t paren_level;              /* parenthesis count, 0 = top level */
	duk_bool_t expr_lhs;                /* expression is left-hand-side compatible */
	duk_bool_t allow_in;                /* current paren level allows 'in' token */

	/* Misc. */
	duk_int_t stmt_next;                /* statement id allocation (running counter) */
	duk_int_t label_next;               /* label id allocation (running counter) */
	duk_int_t catch_depth;              /* catch stack depth */
	duk_int_t with_depth;               /* with stack depth (affects identifier lookups) */
	duk_int_t fnum_next;                /* inner function numbering */
	duk_int_t num_formals;              /* number of formal arguments */
	duk_regconst_t reg_stmt_value;      /* register for writing value of 'non-empty' statements (global or eval code), -1 is marker */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_int_t min_line;                 /* XXX: typing (duk_hcompfunc has duk_uint32_t) */
	duk_int_t max_line;
#endif

	/* Status booleans. */
	duk_uint8_t is_function;             /* is an actual function (not global/eval code) */
	duk_uint8_t is_eval;                 /* is eval code */
	duk_uint8_t is_global;               /* is global code */
	duk_uint8_t is_namebinding;          /* needs a name binding */
	duk_uint8_t is_constructable;        /* result is constructable */
	duk_uint8_t is_setget;               /* is a setter/getter */
	duk_uint8_t is_strict;               /* function is strict */
	duk_uint8_t is_notail;               /* function must not be tail called */
	duk_uint8_t in_directive_prologue;   /* parsing in "directive prologue", recognize directives */
	duk_uint8_t in_scanning;             /* parsing in "scanning" phase (first pass) */
	duk_uint8_t may_direct_eval;         /* function may call direct eval */
	duk_uint8_t id_access_arguments;     /* function refers to 'arguments' identifier */
	duk_uint8_t id_access_slow;          /* function makes one or more slow path accesses that won't match own static variables */
	duk_uint8_t id_access_slow_own;      /* function makes one or more slow path accesses that may match own static variables */
	duk_uint8_t is_arguments_shadowed;   /* argument/function declaration shadows 'arguments' */
	duk_uint8_t needs_shuffle;           /* function needs shuffle registers */
	duk_uint8_t reject_regexp_in_adv;    /* reject RegExp literal on next advance() call; needed for handling IdentifierName productions */
	duk_uint8_t allow_regexp_in_adv;     /* allow RegExp literal on next advance() call */
};

struct duk_compiler_ctx {
	duk_hthread *thr;

	/* filename being compiled (ends up in functions' '_filename' property) */
	duk_hstring *h_filename;            /* borrowed reference */

	/* lexing (tokenization) state (contains two valstack slot indices) */
	duk_lexer_ctx lex;

	/* current and previous token for parsing */
	duk_token prev_token;
	duk_token curr_token;
	duk_idx_t tok11_idx;                /* curr_token slot1 (matches 'lex' slot1_idx) */
	duk_idx_t tok12_idx;                /* curr_token slot2 (matches 'lex' slot2_idx) */
	duk_idx_t tok21_idx;                /* prev_token slot1 */
	duk_idx_t tok22_idx;                /* prev_token slot2 */

	/* recursion limit */
	duk_int_t recursion_depth;
	duk_int_t recursion_limit;

	/* code emission temporary */
	duk_int_t emit_jumpslot_pc;

	/* current function being compiled (embedded instead of pointer for more compact access) */
	duk_compiler_func curr_func;
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL void duk_js_compile(duk_hthread *thr, const duk_uint8_t *src_buffer, duk_size_t src_length, duk_small_uint_t flags);

#endif  /* DUK_JS_COMPILER_H_INCLUDED */
/* #include duk_regexp.h */
/*
 *  Regular expression structs, constants, and bytecode defines.
 */

#if !defined(DUK_REGEXP_H_INCLUDED)
#define DUK_REGEXP_H_INCLUDED

/* maximum bytecode copies for {n,m} quantifiers */
#define DUK_RE_MAX_ATOM_COPIES             1000

/* regexp compilation limits */
#define DUK_RE_COMPILE_TOKEN_LIMIT         100000000L   /* 1e8 */

/* regexp execution limits */
#define DUK_RE_EXECUTE_STEPS_LIMIT         1000000000L  /* 1e9 */

/* regexp opcodes */
#define DUK_REOP_MATCH                     1
#define DUK_REOP_CHAR                      2
#define DUK_REOP_PERIOD                    3
#define DUK_REOP_RANGES                    4
#define DUK_REOP_INVRANGES                 5
#define DUK_REOP_JUMP                      6
#define DUK_REOP_SPLIT1                    7
#define DUK_REOP_SPLIT2                    8
#define DUK_REOP_SQMINIMAL                 9
#define DUK_REOP_SQGREEDY                  10
#define DUK_REOP_SAVE                      11
#define DUK_REOP_WIPERANGE                 12
#define DUK_REOP_LOOKPOS                   13
#define DUK_REOP_LOOKNEG                   14
#define DUK_REOP_BACKREFERENCE             15
#define DUK_REOP_ASSERT_START              16
#define DUK_REOP_ASSERT_END                17
#define DUK_REOP_ASSERT_WORD_BOUNDARY      18
#define DUK_REOP_ASSERT_NOT_WORD_BOUNDARY  19

/* flags */
#define DUK_RE_FLAG_GLOBAL                 (1U << 0)
#define DUK_RE_FLAG_IGNORE_CASE            (1U << 1)
#define DUK_RE_FLAG_MULTILINE              (1U << 2)

struct duk_re_matcher_ctx {
	duk_hthread *thr;

	duk_uint32_t re_flags;
	const duk_uint8_t *input;
	const duk_uint8_t *input_end;
	const duk_uint8_t *bytecode;
	const duk_uint8_t *bytecode_end;
	const duk_uint8_t **saved;  /* allocated from valstack (fixed buffer) */
	duk_uint32_t nsaved;
	duk_uint32_t recursion_depth;
	duk_uint32_t recursion_limit;
	duk_uint32_t steps_count;
	duk_uint32_t steps_limit;
};

struct duk_re_compiler_ctx {
	duk_hthread *thr;

	duk_uint32_t re_flags;
	duk_lexer_ctx lex;
	duk_re_token curr_token;
	duk_bufwriter_ctx bw;
	duk_uint32_t captures;  /* highest capture number emitted so far (used as: ++captures) */
	duk_uint32_t highest_backref;
	duk_uint32_t recursion_depth;
	duk_uint32_t recursion_limit;
	duk_uint32_t nranges;  /* internal temporary value, used for char classes */
};

/*
 *  Prototypes
 */

#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_INTERNAL_DECL void duk_regexp_compile(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_regexp_create_instance(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_regexp_match(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_regexp_match_force_global(duk_hthread *thr);  /* hacky helper for String.prototype.split() */
#endif

#endif  /* DUK_REGEXP_H_INCLUDED */
/* #include duk_heaphdr.h */
/*
 *  Heap header definition and assorted macros, including ref counting.
 *  Access all fields through the accessor macros.
 */

#if !defined(DUK_HEAPHDR_H_INCLUDED)
#define DUK_HEAPHDR_H_INCLUDED

/*
 *  Common heap header
 *
 *  All heap objects share the same flags and refcount fields.  Objects other
 *  than strings also need to have a single or double linked list pointers
 *  for insertion into the "heap allocated" list.  Strings have single linked
 *  list pointers for string table chaining.
 *
 *  Technically, 'h_refcount' must be wide enough to guarantee that it cannot
 *  wrap; otherwise objects might be freed incorrectly after wrapping.  The
 *  default refcount field is 32 bits even on 64-bit systems: while that's in
 *  theory incorrect, the Duktape heap needs to be larger than 64GB for the
 *  count to actually wrap (assuming 16-byte duk_tvals).  This is very unlikely
 *  to ever be an issue, but if it is, disabling DUK_USE_REFCOUNT32 causes
 *  Duktape to use size_t for refcounts which should always be safe.
 *
 *  Heap header size on 32-bit platforms: 8 bytes without reference counting,
 *  16 bytes with reference counting.
 *
 *  Note that 'raw' macros such as DUK_HEAPHDR_GET_REFCOUNT() are not
 *  defined without DUK_USE_REFERENCE_COUNTING, so caller must #if defined()
 *  around them.
 */

/* XXX: macro for shared header fields (avoids some padding issues) */

struct duk_heaphdr {
	duk_uint32_t h_flags;

#if defined(DUK_USE_REFERENCE_COUNTING)
#if defined(DUK_USE_ASSERTIONS)
	/* When assertions enabled, used by mark-and-sweep for refcount
	 * validation.  Largest reasonable type; also detects overflows.
	 */
	duk_size_t h_assert_refcount;
#endif
#if defined(DUK_USE_REFCOUNT16)
	duk_uint16_t h_refcount;
#elif defined(DUK_USE_REFCOUNT32)
	duk_uint32_t h_refcount;
#else
	duk_size_t h_refcount;
#endif
#endif  /* DUK_USE_REFERENCE_COUNTING */

#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t h_next16;
#else
	duk_heaphdr *h_next;
#endif

#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
	/* refcounting requires direct heap frees, which in turn requires a dual linked heap */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t h_prev16;
#else
	duk_heaphdr *h_prev;
#endif
#endif

	/* When DUK_USE_HEAPPTR16 (and DUK_USE_REFCOUNT16) is in use, the
	 * struct won't align nicely to 4 bytes.  This 16-bit extra field
	 * is added to make the alignment clean; the field can be used by
	 * heap objects when 16-bit packing is used.  This field is now
	 * conditional to DUK_USE_HEAPPTR16 only, but it is intended to be
	 * used with DUK_USE_REFCOUNT16 and DUK_USE_DOUBLE_LINKED_HEAP;
	 * this only matter to low memory environments anyway.
	 */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t h_extra16;
#endif
};

struct duk_heaphdr_string {
	/* 16 bits would be enough for shared heaphdr flags and duk_hstring
	 * flags.  The initial parts of duk_heaphdr_string and duk_heaphdr
	 * must match so changing the flags field size here would be quite
	 * awkward.  However, to minimize struct size, we can pack at least
	 * 16 bits of duk_hstring data into the flags field.
	 */
	duk_uint32_t h_flags;

#if defined(DUK_USE_REFERENCE_COUNTING)
#if defined(DUK_USE_ASSERTIONS)
	/* When assertions enabled, used by mark-and-sweep for refcount
	 * validation.  Largest reasonable type; also detects overflows.
	 */
	duk_size_t h_assert_refcount;
#endif
#if defined(DUK_USE_REFCOUNT16)
	duk_uint16_t h_refcount;
	duk_uint16_t h_strextra16;  /* round out to 8 bytes */
#elif defined(DUK_USE_REFCOUNT32)
	duk_uint32_t h_refcount;
#else
	duk_size_t h_refcount;
#endif
#else
	duk_uint16_t h_strextra16;
#endif  /* DUK_USE_REFERENCE_COUNTING */

	duk_hstring *h_next;
	/* No 'h_prev' pointer for strings. */
};

#define DUK_HEAPHDR_FLAGS_TYPE_MASK      0x00000003UL
#define DUK_HEAPHDR_FLAGS_FLAG_MASK      (~DUK_HEAPHDR_FLAGS_TYPE_MASK)

                                             /* 2 bits for heap type */
#define DUK_HEAPHDR_FLAGS_HEAP_START     2   /* 5 heap flags */
#define DUK_HEAPHDR_FLAGS_USER_START     7   /* 25 user flags */

#define DUK_HEAPHDR_HEAP_FLAG_NUMBER(n)  (DUK_HEAPHDR_FLAGS_HEAP_START + (n))
#define DUK_HEAPHDR_USER_FLAG_NUMBER(n)  (DUK_HEAPHDR_FLAGS_USER_START + (n))
#define DUK_HEAPHDR_HEAP_FLAG(n)         (1UL << (DUK_HEAPHDR_FLAGS_HEAP_START + (n)))
#define DUK_HEAPHDR_USER_FLAG(n)         (1UL << (DUK_HEAPHDR_FLAGS_USER_START + (n)))

#define DUK_HEAPHDR_FLAG_REACHABLE       DUK_HEAPHDR_HEAP_FLAG(0)  /* mark-and-sweep: reachable */
#define DUK_HEAPHDR_FLAG_TEMPROOT        DUK_HEAPHDR_HEAP_FLAG(1)  /* mark-and-sweep: children not processed */
#define DUK_HEAPHDR_FLAG_FINALIZABLE     DUK_HEAPHDR_HEAP_FLAG(2)  /* mark-and-sweep: finalizable (on current pass) */
#define DUK_HEAPHDR_FLAG_FINALIZED       DUK_HEAPHDR_HEAP_FLAG(3)  /* mark-and-sweep: finalized (on previous pass) */
#define DUK_HEAPHDR_FLAG_READONLY        DUK_HEAPHDR_HEAP_FLAG(4)  /* read-only object, in code section */

#define DUK_HTYPE_MIN                    0
#define DUK_HTYPE_STRING                 0
#define DUK_HTYPE_OBJECT                 1
#define DUK_HTYPE_BUFFER                 2
#define DUK_HTYPE_MAX                    2

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HEAPHDR_GET_NEXT(heap,h) \
	((duk_heaphdr *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->h_next16))
#define DUK_HEAPHDR_SET_NEXT(heap,h,val)   do { \
		(h)->h_next16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) val); \
	} while (0)
#else
#define DUK_HEAPHDR_GET_NEXT(heap,h)  ((h)->h_next)
#define DUK_HEAPHDR_SET_NEXT(heap,h,val)   do { \
		(h)->h_next = (val); \
	} while (0)
#endif

#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
#if defined(DUK_USE_HEAPPTR16)
#define DUK_HEAPHDR_GET_PREV(heap,h) \
	((duk_heaphdr *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->h_prev16))
#define DUK_HEAPHDR_SET_PREV(heap,h,val)   do { \
		(h)->h_prev16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (val)); \
	} while (0)
#else
#define DUK_HEAPHDR_GET_PREV(heap,h)       ((h)->h_prev)
#define DUK_HEAPHDR_SET_PREV(heap,h,val)   do { \
		(h)->h_prev = (val); \
	} while (0)
#endif
#endif

#if defined(DUK_USE_REFERENCE_COUNTING)
#define DUK_HEAPHDR_GET_REFCOUNT(h)   ((h)->h_refcount)
#define DUK_HEAPHDR_SET_REFCOUNT(h,val)  do { \
		(h)->h_refcount = (val); \
		DUK_ASSERT((h)->h_refcount == (val));  /* No truncation. */ \
	} while (0)
#define DUK_HEAPHDR_PREINC_REFCOUNT(h)  (++(h)->h_refcount)  /* result: updated refcount */
#define DUK_HEAPHDR_PREDEC_REFCOUNT(h)  (--(h)->h_refcount)  /* result: updated refcount */
#else
/* refcount macros not defined without refcounting, caller must #if defined() now */
#endif  /* DUK_USE_REFERENCE_COUNTING */

/*
 *  Note: type is treated as a field separate from flags, so some masking is
 *  involved in the macros below.
 */

#define DUK_HEAPHDR_GET_FLAGS_RAW(h)  ((h)->h_flags)
#define DUK_HEAPHDR_SET_FLAGS_RAW(h,val)  do { \
		(h)->h_flags = (val); } \
	}
#define DUK_HEAPHDR_GET_FLAGS(h)      ((h)->h_flags & DUK_HEAPHDR_FLAGS_FLAG_MASK)
#define DUK_HEAPHDR_SET_FLAGS(h,val)  do { \
		(h)->h_flags = ((h)->h_flags & ~(DUK_HEAPHDR_FLAGS_FLAG_MASK)) | (val); \
	} while (0)
#define DUK_HEAPHDR_GET_TYPE(h)       ((h)->h_flags & DUK_HEAPHDR_FLAGS_TYPE_MASK)
#define DUK_HEAPHDR_SET_TYPE(h,val)   do { \
		(h)->h_flags = ((h)->h_flags & ~(DUK_HEAPHDR_FLAGS_TYPE_MASK)) | (val); \
	} while (0)

/* Comparison for type >= DUK_HTYPE_MIN skipped; because DUK_HTYPE_MIN is zero
 * and the comparison is unsigned, it's always true and generates warnings.
 */
#define DUK_HEAPHDR_HTYPE_VALID(h)    ( \
	DUK_HEAPHDR_GET_TYPE((h)) <= DUK_HTYPE_MAX \
	)

#define DUK_HEAPHDR_SET_TYPE_AND_FLAGS(h,tval,fval)  do { \
		(h)->h_flags = ((tval) & DUK_HEAPHDR_FLAGS_TYPE_MASK) | \
		               ((fval) & DUK_HEAPHDR_FLAGS_FLAG_MASK); \
	} while (0)

#define DUK_HEAPHDR_SET_FLAG_BITS(h,bits)  do { \
		DUK_ASSERT(((bits) & ~(DUK_HEAPHDR_FLAGS_FLAG_MASK)) == 0); \
		(h)->h_flags |= (bits); \
	} while (0)

#define DUK_HEAPHDR_CLEAR_FLAG_BITS(h,bits)  do { \
		DUK_ASSERT(((bits) & ~(DUK_HEAPHDR_FLAGS_FLAG_MASK)) == 0); \
		(h)->h_flags &= ~((bits)); \
	} while (0)

#define DUK_HEAPHDR_CHECK_FLAG_BITS(h,bits)  (((h)->h_flags & (bits)) != 0)

#define DUK_HEAPHDR_SET_REACHABLE(h)      DUK_HEAPHDR_SET_FLAG_BITS((h),DUK_HEAPHDR_FLAG_REACHABLE)
#define DUK_HEAPHDR_CLEAR_REACHABLE(h)    DUK_HEAPHDR_CLEAR_FLAG_BITS((h),DUK_HEAPHDR_FLAG_REACHABLE)
#define DUK_HEAPHDR_HAS_REACHABLE(h)      DUK_HEAPHDR_CHECK_FLAG_BITS((h),DUK_HEAPHDR_FLAG_REACHABLE)

#define DUK_HEAPHDR_SET_TEMPROOT(h)       DUK_HEAPHDR_SET_FLAG_BITS((h),DUK_HEAPHDR_FLAG_TEMPROOT)
#define DUK_HEAPHDR_CLEAR_TEMPROOT(h)     DUK_HEAPHDR_CLEAR_FLAG_BITS((h),DUK_HEAPHDR_FLAG_TEMPROOT)
#define DUK_HEAPHDR_HAS_TEMPROOT(h)       DUK_HEAPHDR_CHECK_FLAG_BITS((h),DUK_HEAPHDR_FLAG_TEMPROOT)

#define DUK_HEAPHDR_SET_FINALIZABLE(h)    DUK_HEAPHDR_SET_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZABLE)
#define DUK_HEAPHDR_CLEAR_FINALIZABLE(h)  DUK_HEAPHDR_CLEAR_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZABLE)
#define DUK_HEAPHDR_HAS_FINALIZABLE(h)    DUK_HEAPHDR_CHECK_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZABLE)

#define DUK_HEAPHDR_SET_FINALIZED(h)      DUK_HEAPHDR_SET_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZED)
#define DUK_HEAPHDR_CLEAR_FINALIZED(h)    DUK_HEAPHDR_CLEAR_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZED)
#define DUK_HEAPHDR_HAS_FINALIZED(h)      DUK_HEAPHDR_CHECK_FLAG_BITS((h),DUK_HEAPHDR_FLAG_FINALIZED)

#define DUK_HEAPHDR_SET_READONLY(h)       DUK_HEAPHDR_SET_FLAG_BITS((h),DUK_HEAPHDR_FLAG_READONLY)
#define DUK_HEAPHDR_CLEAR_READONLY(h)     DUK_HEAPHDR_CLEAR_FLAG_BITS((h),DUK_HEAPHDR_FLAG_READONLY)
#define DUK_HEAPHDR_HAS_READONLY(h)       DUK_HEAPHDR_CHECK_FLAG_BITS((h),DUK_HEAPHDR_FLAG_READONLY)

/* get or set a range of flags; m=first bit number, n=number of bits */
#define DUK_HEAPHDR_GET_FLAG_RANGE(h,m,n)  (((h)->h_flags >> (m)) & ((1UL << (n)) - 1UL))

#define DUK_HEAPHDR_SET_FLAG_RANGE(h,m,n,v)  do { \
		(h)->h_flags = \
			((h)->h_flags & (~(((1UL << (n)) - 1UL) << (m)))) \
			| ((v) << (m)); \
	} while (0)

/* init pointer fields to null */
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
#define DUK_HEAPHDR_INIT_NULLS(h)       do { \
		DUK_HEAPHDR_SET_NEXT((h), (void *) NULL); \
		DUK_HEAPHDR_SET_PREV((h), (void *) NULL); \
	} while (0)
#else
#define DUK_HEAPHDR_INIT_NULLS(h)       do { \
		DUK_HEAPHDR_SET_NEXT((h), (void *) NULL); \
	} while (0)
#endif

#define DUK_HEAPHDR_STRING_INIT_NULLS(h)  do { \
		(h)->h_next = NULL; \
	} while (0)

/*
 *  Type tests
 */

/* Take advantage of the fact that for DUK_HTYPE_xxx numbers the lowest bit
 * is only set for DUK_HTYPE_OBJECT (= 1).
 */
#if 0
#define DUK_HEAPHDR_IS_OBJECT(h) (DUK_HEAPHDR_GET_TYPE((h)) == DUK_HTYPE_OBJECT)
#endif
#define DUK_HEAPHDR_IS_OBJECT(h) ((h)->h_flags & 0x01UL)
#define DUK_HEAPHDR_IS_STRING(h) (DUK_HEAPHDR_GET_TYPE((h)) == DUK_HTYPE_STRING)
#define DUK_HEAPHDR_IS_BUFFER(h) (DUK_HEAPHDR_GET_TYPE((h)) == DUK_HTYPE_BUFFER)

/*
 *  Assert helpers
 */

/* Check that prev/next links are consistent: if e.g. h->prev is != NULL,
 * h->prev->next should point back to h.
 */
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_heaphdr_assert_valid_subclassed(duk_heaphdr *h);
DUK_INTERNAL_DECL void duk_heaphdr_assert_links(duk_heap *heap, duk_heaphdr *h);
DUK_INTERNAL_DECL void duk_heaphdr_assert_valid(duk_heaphdr *h);
#define DUK_HEAPHDR_ASSERT_LINKS(heap,h)  do { duk_heaphdr_assert_links((heap), (h)); } while (0)
#define DUK_HEAPHDR_ASSERT_VALID(h)  do { duk_heaphdr_assert_valid((h)); } while (0)
#else
#define DUK_HEAPHDR_ASSERT_LINKS(heap,h)  do {} while (0)
#define DUK_HEAPHDR_ASSERT_VALID(h)  do {} while (0)
#endif

#endif  /* DUK_HEAPHDR_H_INCLUDED */
/* #include duk_refcount.h */
/*
 *  Reference counting helper macros.  The macros take a thread argument
 *  and must thus always be executed in a specific thread context.  The
 *  thread argument is not really needed anymore: DECREF can operate with
 *  a heap pointer only, and INCREF needs neither.
 */

#if !defined(DUK_REFCOUNT_H_INCLUDED)
#define DUK_REFCOUNT_H_INCLUDED

#if defined(DUK_USE_REFERENCE_COUNTING)

#if defined(DUK_USE_ROM_OBJECTS)
/* With ROM objects "needs refcount update" is true when the value is
 * heap allocated and is not a ROM object.
 */
/* XXX: double evaluation for 'tv' argument. */
#define DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv) \
	(DUK_TVAL_IS_HEAP_ALLOCATED((tv)) && !DUK_HEAPHDR_HAS_READONLY(DUK_TVAL_GET_HEAPHDR((tv))))
#define DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE(h)  (!DUK_HEAPHDR_HAS_READONLY((h)))
#else  /* DUK_USE_ROM_OBJECTS */
/* Without ROM objects "needs refcount update" == is heap allocated. */
#define DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)    DUK_TVAL_IS_HEAP_ALLOCATED((tv))
#define DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE(h)  1
#endif  /* DUK_USE_ROM_OBJECTS */

/* Fast variants, inline refcount operations except for refzero handling.
 * Can be used explicitly when speed is always more important than size.
 * For a good compiler and a single file build, these are basically the
 * same as a forced inline.
 */
#define DUK_TVAL_INCREF_FAST(thr,tv) do { \
		duk_tval *duk__tv = (tv); \
		DUK_ASSERT(duk__tv != NULL); \
		if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk__tv)) { \
			duk_heaphdr *duk__h = DUK_TVAL_GET_HEAPHDR(duk__tv); \
			DUK_ASSERT(duk__h != NULL); \
			DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(duk__h)); \
			DUK_HEAPHDR_PREINC_REFCOUNT(duk__h); \
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(duk__h) != 0);  /* No wrapping. */ \
		} \
	} while (0)
#define DUK_TVAL_DECREF_FAST(thr,tv) do { \
		duk_tval *duk__tv = (tv); \
		DUK_ASSERT(duk__tv != NULL); \
		if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk__tv)) { \
			duk_heaphdr *duk__h = DUK_TVAL_GET_HEAPHDR(duk__tv); \
			DUK_ASSERT(duk__h != NULL); \
			DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(duk__h)); \
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(duk__h) > 0); \
			if (DUK_HEAPHDR_PREDEC_REFCOUNT(duk__h) == 0) { \
				duk_heaphdr_refzero((thr), duk__h); \
			} \
		} \
	} while (0)
#define DUK_TVAL_DECREF_NORZ_FAST(thr,tv) do { \
		duk_tval *duk__tv = (tv); \
		DUK_ASSERT(duk__tv != NULL); \
		if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk__tv)) { \
			duk_heaphdr *duk__h = DUK_TVAL_GET_HEAPHDR(duk__tv); \
			DUK_ASSERT(duk__h != NULL); \
			DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(duk__h)); \
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(duk__h) > 0); \
			if (DUK_HEAPHDR_PREDEC_REFCOUNT(duk__h) == 0) { \
				duk_heaphdr_refzero_norz((thr), duk__h); \
			} \
		} \
	} while (0)
#define DUK_HEAPHDR_INCREF_FAST(thr,h) do { \
		duk_heaphdr *duk__h = (duk_heaphdr *) (h); \
		DUK_ASSERT(duk__h != NULL); \
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(duk__h)); \
		if (DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE(duk__h)) { \
			DUK_HEAPHDR_PREINC_REFCOUNT(duk__h); \
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(duk__h) != 0);  /* No wrapping. */ \
		} \
	} while (0)
#define DUK_HEAPHDR_DECREF_FAST_RAW(thr,h,rzcall,rzcast) do { \
		duk_heaphdr *duk__h = (duk_heaphdr *) (h); \
		DUK_ASSERT(duk__h != NULL); \
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(duk__h)); \
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(duk__h) > 0); \
		if (DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE(duk__h)) { \
			if (DUK_HEAPHDR_PREDEC_REFCOUNT(duk__h) == 0) { \
				(rzcall)((thr), (rzcast) duk__h); \
			} \
		} \
	} while (0)
#define DUK_HEAPHDR_DECREF_FAST(thr,h) \
	DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_heaphdr_refzero,duk_heaphdr *)
#define DUK_HEAPHDR_DECREF_NORZ_FAST(thr,h) \
	DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_heaphdr_refzero_norz,duk_heaphdr *)

/* Slow variants, call to a helper to reduce code size.
 * Can be used explicitly when size is always more important than speed.
 */
#define DUK_TVAL_INCREF_SLOW(thr,tv)         do { duk_tval_incref((tv)); } while (0)
#define DUK_TVAL_DECREF_SLOW(thr,tv)         do { duk_tval_decref((thr), (tv)); } while (0)
#define DUK_TVAL_DECREF_NORZ_SLOW(thr,tv)    do { duk_tval_decref_norz((thr), (tv)); } while (0)
#define DUK_HEAPHDR_INCREF_SLOW(thr,h)       do { duk_heaphdr_incref((duk_heaphdr *) (h)); } while (0)
#define DUK_HEAPHDR_DECREF_SLOW(thr,h)       do { duk_heaphdr_decref((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HEAPHDR_DECREF_NORZ_SLOW(thr,h)  do { duk_heaphdr_decref_norz((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HSTRING_INCREF_SLOW(thr,h)       do { duk_heaphdr_incref((duk_heaphdr *) (h)); } while (0)
#define DUK_HSTRING_DECREF_SLOW(thr,h)       do { duk_heaphdr_decref((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HSTRING_DECREF_NORZ_SLOW(thr,h)  do { duk_heaphdr_decref_norz((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HBUFFER_INCREF_SLOW(thr,h)       do { duk_heaphdr_incref((duk_heaphdr *) (h)); } while (0)
#define DUK_HBUFFER_DECREF_SLOW(thr,h)       do { duk_heaphdr_decref((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HBUFFER_DECREF_NORZ_SLOW(thr,h)  do { duk_heaphdr_decref_norz((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HOBJECT_INCREF_SLOW(thr,h)       do { duk_heaphdr_incref((duk_heaphdr *) (h)); } while (0)
#define DUK_HOBJECT_DECREF_SLOW(thr,h)       do { duk_heaphdr_decref((thr), (duk_heaphdr *) (h)); } while (0)
#define DUK_HOBJECT_DECREF_NORZ_SLOW(thr,h)  do { duk_heaphdr_decref_norz((thr), (duk_heaphdr *) (h)); } while (0)

/* Default variants.  Selection depends on speed/size preference.
 * Concretely: with gcc 4.8.1 -Os x64 the difference in final binary
 * is about +1kB for _FAST variants.
 */
#if defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
/* XXX: It would be nice to specialize for specific duk_hobject subtypes
 * but current refzero queue handling prevents that.
 */
#define DUK_TVAL_INCREF(thr,tv)                DUK_TVAL_INCREF_FAST((thr),(tv))
#define DUK_TVAL_DECREF(thr,tv)                DUK_TVAL_DECREF_FAST((thr),(tv))
#define DUK_TVAL_DECREF_NORZ(thr,tv)           DUK_TVAL_DECREF_NORZ_FAST((thr),(tv))
#define DUK_HEAPHDR_INCREF(thr,h)              DUK_HEAPHDR_INCREF_FAST((thr),(h))
#define DUK_HEAPHDR_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_heaphdr_refzero,duk_heaphdr *)
#define DUK_HEAPHDR_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_heaphdr_refzero_norz,duk_heaphdr *)
#define DUK_HSTRING_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HSTRING_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hstring_refzero,duk_hstring *)
#define DUK_HSTRING_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hstring_refzero,duk_hstring *)  /* no 'norz' variant */
#define DUK_HOBJECT_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HOBJECT_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero,duk_hobject *)
#define DUK_HOBJECT_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero_norz,duk_hobject *)
#define DUK_HBUFFER_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HBUFFER_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hbuffer_refzero,duk_hbuffer *)
#define DUK_HBUFFER_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hbuffer_refzero,duk_hbuffer *)  /* no 'norz' variant */
#define DUK_HCOMPFUNC_INCREF(thr,h)            DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HCOMPFUNC_DECREF(thr,h)            DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero,duk_hobject *)
#define DUK_HCOMPFUNC_DECREF_NORZ(thr,h)       DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero_norz,duk_hobject *)
#define DUK_HNATFUNC_INCREF(thr,h)             DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HNATFUNC_DECREF(thr,h)             DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero,duk_hobject *)
#define DUK_HNATFUNC_DECREF_NORZ(thr,h)        DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero_norz,duk_hobject *)
#define DUK_HBUFOBJ_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HBUFOBJ_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero,duk_hobject *)
#define DUK_HBUFOBJ_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero_norz,duk_hobject *)
#define DUK_HTHREAD_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HTHREAD_DECREF(thr,h)              DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero,duk_hobject *)
#define DUK_HTHREAD_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_FAST_RAW((thr),(h),duk_hobject_refzero_norz,duk_hobject *)
#else
#define DUK_TVAL_INCREF(thr,tv)                DUK_TVAL_INCREF_SLOW((thr),(tv))
#define DUK_TVAL_DECREF(thr,tv)                DUK_TVAL_DECREF_SLOW((thr),(tv))
#define DUK_TVAL_DECREF_NORZ(thr,tv)           DUK_TVAL_DECREF_NORZ_SLOW((thr),(tv))
#define DUK_HEAPHDR_INCREF(thr,h)              DUK_HEAPHDR_INCREF_SLOW((thr),(h))
#define DUK_HEAPHDR_DECREF(thr,h)              DUK_HEAPHDR_DECREF_SLOW((thr),(h))
#define DUK_HEAPHDR_DECREF_NORZ(thr,h)         DUK_HEAPHDR_DECREF_NORZ_SLOW((thr),(h))
#define DUK_HSTRING_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HSTRING_DECREF(thr,h)              DUK_HSTRING_DECREF_SLOW((thr),(h))
#define DUK_HSTRING_DECREF_NORZ(thr,h)         DUK_HSTRING_DECREF_NORZ_SLOW((thr),(h))
#define DUK_HOBJECT_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HOBJECT_DECREF(thr,h)              DUK_HOBJECT_DECREF_SLOW((thr),(h))
#define DUK_HOBJECT_DECREF_NORZ(thr,h)         DUK_HOBJECT_DECREF_NORZ_SLOW((thr),(h))
#define DUK_HBUFFER_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) (h))
#define DUK_HBUFFER_DECREF(thr,h)              DUK_HBUFFER_DECREF_SLOW((thr),(h))
#define DUK_HBUFFER_DECREF_NORZ(thr,h)         DUK_HBUFFER_DECREF_NORZ_SLOW((thr),(h))
#define DUK_HCOMPFUNC_INCREF(thr,h)            DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HCOMPFUNC_DECREF(thr,h)            DUK_HOBJECT_DECREF_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HCOMPFUNC_DECREF_NORZ(thr,h)       DUK_HOBJECT_DECREF_NORZ_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HNATFUNC_INCREF(thr,h)             DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HNATFUNC_DECREF(thr,h)             DUK_HOBJECT_DECREF_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HNATFUNC_DECREF_NORZ(thr,h)        DUK_HOBJECT_DECREF_NORZ_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HBUFOBJ_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HBUFOBJ_DECREF(thr,h)              DUK_HOBJECT_DECREF_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HBUFOB_DECREF_NORZ(thr,h)          DUK_HOBJECT_DECREF_NORZ_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HTHREAD_INCREF(thr,h)              DUK_HEAPHDR_INCREF((thr),(duk_heaphdr *) &(h)->obj)
#define DUK_HTHREAD_DECREF(thr,h)              DUK_HOBJECT_DECREF_SLOW((thr),(duk_hobject *) &(h)->obj)
#define DUK_HTHREAD_DECREF_NORZ(thr,h)         DUK_HOBJECT_DECREF_NORZ_SLOW((thr),(duk_hobject *) &(h)->obj)
#endif

/* Convenience for some situations; the above macros don't allow NULLs
 * for performance reasons.  Macros cover only actually needed cases.
 */
#define DUK_HEAPHDR_INCREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HEAPHDR_INCREF((thr), (duk_heaphdr *) (h)); \
		} \
	} while (0)
#define DUK_HEAPHDR_DECREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HEAPHDR_DECREF((thr), (duk_heaphdr *) (h)); \
		} \
	} while (0)
#define DUK_HEAPHDR_DECREF_NORZ_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HEAPHDR_DECREF_NORZ((thr), (duk_heaphdr *) (h)); \
		} \
	} while (0)
#define DUK_HOBJECT_INCREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HOBJECT_INCREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HOBJECT_DECREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HOBJECT_DECREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HOBJECT_DECREF_NORZ((thr), (h)); \
		} \
	} while (0)
#define DUK_HBUFFER_INCREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HBUFFER_INCREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HBUFFER_DECREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HBUFFER_DECREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HBUFFER_DECREF_NORZ_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HBUFFER_DECREF_NORZ((thr), (h)); \
		} \
	} while (0)
#define DUK_HTHREAD_INCREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HTHREAD_INCREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HTHREAD_DECREF_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HTHREAD_DECREF((thr), (h)); \
		} \
	} while (0)
#define DUK_HTHREAD_DECREF_NORZ_ALLOWNULL(thr,h) do { \
		if ((h) != NULL) { \
			DUK_HTHREAD_DECREF_NORZ((thr), (h)); \
		} \
	} while (0)

/* Called after one or more DECREF NORZ calls to handle pending side effects.
 * At present DECREF NORZ does freeing inline but doesn't execute finalizers,
 * so these macros check for pending finalizers and execute them.  The FAST
 * variant is performance critical.
 */
#if defined(DUK_USE_FINALIZER_SUPPORT)
#define DUK_REFZERO_CHECK_FAST(thr) do { \
		duk_refzero_check_fast((thr)); \
	} while (0)
#define DUK_REFZERO_CHECK_SLOW(thr) do { \
		duk_refzero_check_slow((thr)); \
	} while (0)
#else  /* DUK_USE_FINALIZER_SUPPORT */
#define DUK_REFZERO_CHECK_FAST(thr) do { } while (0)
#define DUK_REFZERO_CHECK_SLOW(thr) do { } while (0)
#endif  /* DUK_USE_FINALIZER_SUPPORT */

/*
 *  Macros to set a duk_tval and update refcount of the target (decref the
 *  old value and incref the new value if necessary).  This is both performance
 *  and footprint critical; any changes made should be measured for size/speed.
 */

#define DUK_TVAL_SET_UNDEFINED_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_UNDEFINED(tv__dst); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_UNDEFINED(tv__dst); \
		DUK_TVAL_DECREF_NORZ((thr), &tv__tmp); \
	} while (0)

#define DUK_TVAL_SET_UNUSED_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_UNUSED(tv__dst); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_NULL_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_NULL(tv__dst); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_BOOLEAN_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_BOOLEAN(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_NUMBER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_NUMBER(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#define DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#define DUK_TVAL_SET_DOUBLE_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_DOUBLE(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#define DUK_TVAL_SET_NAN_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_NAN(tv__dst); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_I48_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_I48(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#define DUK_TVAL_SET_I32_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_I32(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#define DUK_TVAL_SET_U32_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_U32(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)
#else
#define DUK_TVAL_SET_DOUBLE_CAST_UPDREF(thr,tvptr_dst,newval) \
	DUK_TVAL_SET_DOUBLE_UPDREF((thr), (tvptr_dst), (duk_double_t) (newval))
#endif  /* DUK_USE_FASTINT */

#define DUK_TVAL_SET_LIGHTFUNC_UPDREF_ALT0(thr,tvptr_dst,lf_v,lf_fp,lf_flags) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_LIGHTFUNC(tv__dst, (lf_v), (lf_fp), (lf_flags)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_STRING_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_STRING(tv__dst, (newval)); \
		DUK_HSTRING_INCREF((thr), (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_OBJECT_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_OBJECT(tv__dst, (newval)); \
		DUK_HOBJECT_INCREF((thr), (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_BUFFER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_BUFFER(tv__dst, (newval)); \
		DUK_HBUFFER_INCREF((thr), (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

#define DUK_TVAL_SET_POINTER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; duk_tval tv__tmp; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_POINTER(tv__dst, (newval)); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

/* DUK_TVAL_SET_TVAL_UPDREF() is used a lot in executor, property lookups,
 * etc, so it's very important for performance.  Measure when changing.
 *
 * NOTE: the source and destination duk_tval pointers may be the same, and
 * the macros MUST deal with that correctly.
 */

/* Original idiom used, minimal code size. */
#define DUK_TVAL_SET_TVAL_UPDREF_ALT0(thr,tvptr_dst,tvptr_src) do { \
		duk_tval *tv__dst, *tv__src; duk_tval tv__tmp; \
		tv__dst = (tvptr_dst); tv__src = (tvptr_src); \
		DUK_TVAL_SET_TVAL(&tv__tmp, tv__dst); \
		DUK_TVAL_SET_TVAL(tv__dst, tv__src); \
		DUK_TVAL_INCREF((thr), tv__src); \
		DUK_TVAL_DECREF((thr), &tv__tmp);  /* side effects */ \
	} while (0)

/* Faster alternative: avoid making a temporary copy of tvptr_dst and use
 * fast incref/decref macros.
 */
#define DUK_TVAL_SET_TVAL_UPDREF_ALT1(thr,tvptr_dst,tvptr_src) do { \
		duk_tval *tv__dst, *tv__src; duk_heaphdr *h__obj; \
		tv__dst = (tvptr_dst); tv__src = (tvptr_src); \
		DUK_TVAL_INCREF_FAST((thr), tv__src); \
		if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv__dst)) { \
			h__obj = DUK_TVAL_GET_HEAPHDR(tv__dst); \
			DUK_ASSERT(h__obj != NULL); \
			DUK_TVAL_SET_TVAL(tv__dst, tv__src); \
			DUK_HEAPHDR_DECREF_FAST((thr), h__obj);  /* side effects */ \
		} else { \
			DUK_TVAL_SET_TVAL(tv__dst, tv__src); \
		} \
	} while (0)

/* XXX: no optimized variants yet */
#define DUK_TVAL_SET_UNDEFINED_UPDREF         DUK_TVAL_SET_UNDEFINED_UPDREF_ALT0
#define DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ    DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ_ALT0
#define DUK_TVAL_SET_UNUSED_UPDREF            DUK_TVAL_SET_UNUSED_UPDREF_ALT0
#define DUK_TVAL_SET_NULL_UPDREF              DUK_TVAL_SET_NULL_UPDREF_ALT0
#define DUK_TVAL_SET_BOOLEAN_UPDREF           DUK_TVAL_SET_BOOLEAN_UPDREF_ALT0
#define DUK_TVAL_SET_NUMBER_UPDREF            DUK_TVAL_SET_NUMBER_UPDREF_ALT0
#define DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF    DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF_ALT0
#define DUK_TVAL_SET_DOUBLE_UPDREF            DUK_TVAL_SET_DOUBLE_UPDREF_ALT0
#define DUK_TVAL_SET_NAN_UPDREF               DUK_TVAL_SET_NAN_UPDREF_ALT0
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_I48_UPDREF               DUK_TVAL_SET_I48_UPDREF_ALT0
#define DUK_TVAL_SET_I32_UPDREF               DUK_TVAL_SET_I32_UPDREF_ALT0
#define DUK_TVAL_SET_U32_UPDREF               DUK_TVAL_SET_U32_UPDREF_ALT0
#else
#define DUK_TVAL_SET_I48_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF  /* XXX: fast int-to-double */
#define DUK_TVAL_SET_I32_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF
#define DUK_TVAL_SET_U32_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF
#endif  /* DUK_USE_FASTINT */
#define DUK_TVAL_SET_FASTINT_UPDREF           DUK_TVAL_SET_I48_UPDREF  /* convenience */
#define DUK_TVAL_SET_LIGHTFUNC_UPDREF         DUK_TVAL_SET_LIGHTFUNC_UPDREF_ALT0
#define DUK_TVAL_SET_STRING_UPDREF            DUK_TVAL_SET_STRING_UPDREF_ALT0
#define DUK_TVAL_SET_OBJECT_UPDREF            DUK_TVAL_SET_OBJECT_UPDREF_ALT0
#define DUK_TVAL_SET_BUFFER_UPDREF            DUK_TVAL_SET_BUFFER_UPDREF_ALT0
#define DUK_TVAL_SET_POINTER_UPDREF           DUK_TVAL_SET_POINTER_UPDREF_ALT0

#if defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
/* Optimized for speed. */
#define DUK_TVAL_SET_TVAL_UPDREF              DUK_TVAL_SET_TVAL_UPDREF_ALT1
#define DUK_TVAL_SET_TVAL_UPDREF_FAST         DUK_TVAL_SET_TVAL_UPDREF_ALT1
#define DUK_TVAL_SET_TVAL_UPDREF_SLOW         DUK_TVAL_SET_TVAL_UPDREF_ALT0
#else
/* Optimized for size. */
#define DUK_TVAL_SET_TVAL_UPDREF              DUK_TVAL_SET_TVAL_UPDREF_ALT0
#define DUK_TVAL_SET_TVAL_UPDREF_FAST         DUK_TVAL_SET_TVAL_UPDREF_ALT0
#define DUK_TVAL_SET_TVAL_UPDREF_SLOW         DUK_TVAL_SET_TVAL_UPDREF_ALT0
#endif

#else  /* DUK_USE_REFERENCE_COUNTING */

#define DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)     0
#define DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE(h)   0

#define DUK_TVAL_INCREF_FAST(thr,v)            do {} while (0) /* nop */
#define DUK_TVAL_DECREF_FAST(thr,v)            do {} while (0) /* nop */
#define DUK_TVAL_DECREF_NORZ_FAST(thr,v)       do {} while (0) /* nop */
#define DUK_TVAL_INCREF_SLOW(thr,v)            do {} while (0) /* nop */
#define DUK_TVAL_DECREF_SLOW(thr,v)            do {} while (0) /* nop */
#define DUK_TVAL_DECREF_NORZ_SLOW(thr,v)       do {} while (0) /* nop */
#define DUK_TVAL_INCREF(thr,v)                 do {} while (0) /* nop */
#define DUK_TVAL_DECREF(thr,v)                 do {} while (0) /* nop */
#define DUK_TVAL_DECREF_NORZ(thr,v)            do {} while (0) /* nop */
#define DUK_HEAPHDR_INCREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF_NORZ_FAST(thr,h)    do {} while (0) /* nop */
#define DUK_HEAPHDR_INCREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF_NORZ_SLOW(thr,h)    do {} while (0) /* nop */
#define DUK_HEAPHDR_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HEAPHDR_DECREF_NORZ(thr,h)         do {} while (0) /* nop */
#define DUK_HSTRING_INCREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HSTRING_DECREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HSTRING_DECREF_NORZ_FAST(thr,h)    do {} while (0) /* nop */
#define DUK_HSTRING_INCREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HSTRING_DECREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HSTRING_DECREF_NORZ_SLOW(thr,h)    do {} while (0) /* nop */
#define DUK_HSTRING_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HSTRING_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HSTRING_DECREF_NORZ(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_INCREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_NORZ_FAST(thr,h)    do {} while (0) /* nop */
#define DUK_HOBJECT_INCREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_NORZ_SLOW(thr,h)    do {} while (0) /* nop */
#define DUK_HOBJECT_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_NORZ(thr,h)         do {} while (0) /* nop */
#define DUK_HBUFFER_INCREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_FAST(thr,h)         do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_NORZ_FAST(thr,h)    do {} while (0) /* nop */
#define DUK_HBUFFER_INCREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_SLOW(thr,h)         do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_NORZ_SLOW(thr,h)    do {} while (0) /* nop */
#define DUK_HBUFFER_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_NORZ(thr,h)         do {} while (0) /* nop */

#define DUK_HCOMPFUNC_INCREF(thr,h)            do {} while (0) /* nop */
#define DUK_HCOMPFUNC_DECREF(thr,h)            do {} while (0) /* nop */
#define DUK_HCOMPFUNC_DECREF_NORZ(thr,h)       do {} while (0) /* nop */
#define DUK_HNATFUNC_INCREF(thr,h)             do {} while (0) /* nop */
#define DUK_HNATFUNC_DECREF(thr,h)             do {} while (0) /* nop */
#define DUK_HNATFUNC_DECREF_NORZ(thr,h)        do {} while (0) /* nop */
#define DUK_HBUFOBJ_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HBUFOBJ_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HBUFOBJ_DECREF_NORZ(thr,h)         do {} while (0) /* nop */
#define DUK_HTHREAD_INCREF(thr,h)              do {} while (0) /* nop */
#define DUK_HTHREAD_DECREF(thr,h)              do {} while (0) /* nop */
#define DUK_HTHREAD_DECREF_NORZ(thr,h)         do {} while (0) /* nop */
#define DUK_HOBJECT_INCREF_ALLOWNULL(thr,h)    do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_ALLOWNULL(thr,h)    do {} while (0) /* nop */
#define DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr,h)  do {} while (0) /* nop */
#define DUK_HBUFFER_INCREF_ALLOWNULL(thr,h)    do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_ALLOWNULL(thr,h)    do {} while (0) /* nop */
#define DUK_HBUFFER_DECREF_NORZ_ALLOWNULL(thr,h)  do {} while (0) /* nop */

#define DUK_REFZERO_CHECK_FAST(thr)            do {} while (0) /* nop */
#define DUK_REFZERO_CHECK_SLOW(thr)            do {} while (0) /* nop */

#define DUK_TVAL_SET_UNDEFINED_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_UNDEFINED(tv__dst); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_UNUSED_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_UNUSED(tv__dst); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_NULL_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_NULL(tv__dst); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_BOOLEAN_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_BOOLEAN(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_NUMBER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_NUMBER(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#define DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_NUMBER_CHKFAST_FAST(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#define DUK_TVAL_SET_DOUBLE_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_DOUBLE(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#define DUK_TVAL_SET_NAN_UPDREF_ALT0(thr,tvptr_dst) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_NAN(tv__dst); \
		DUK_UNREF((thr)); \
	} while (0)
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_I48_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_I48(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#define DUK_TVAL_SET_I32_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_I32(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#define DUK_TVAL_SET_U32_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_U32(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)
#else
#define DUK_TVAL_SET_DOUBLE_CAST_UPDREF(thr,tvptr_dst,newval) \
	DUK_TVAL_SET_DOUBLE_UPDREF((thr), (tvptr_dst), (duk_double_t) (newval))
#endif  /* DUK_USE_FASTINT */

#define DUK_TVAL_SET_LIGHTFUNC_UPDREF_ALT0(thr,tvptr_dst,lf_v,lf_fp,lf_flags) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_LIGHTFUNC(tv__dst, (lf_v), (lf_fp), (lf_flags)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_STRING_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_STRING(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_OBJECT_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_OBJECT(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_BUFFER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_BUFFER(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_POINTER_UPDREF_ALT0(thr,tvptr_dst,newval) do { \
		duk_tval *tv__dst; tv__dst = (tvptr_dst); \
		DUK_TVAL_SET_POINTER(tv__dst, (newval)); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_TVAL_UPDREF_ALT0(thr,tvptr_dst,tvptr_src) do { \
		duk_tval *tv__dst, *tv__src; \
		tv__dst = (tvptr_dst); tv__src = (tvptr_src); \
		DUK_TVAL_SET_TVAL(tv__dst, tv__src); \
		DUK_UNREF((thr)); \
	} while (0)

#define DUK_TVAL_SET_UNDEFINED_UPDREF         DUK_TVAL_SET_UNDEFINED_UPDREF_ALT0
#define DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ    DUK_TVAL_SET_UNDEFINED_UPDREF_ALT0
#define DUK_TVAL_SET_UNUSED_UPDREF            DUK_TVAL_SET_UNUSED_UPDREF_ALT0
#define DUK_TVAL_SET_NULL_UPDREF              DUK_TVAL_SET_NULL_UPDREF_ALT0
#define DUK_TVAL_SET_BOOLEAN_UPDREF           DUK_TVAL_SET_BOOLEAN_UPDREF_ALT0
#define DUK_TVAL_SET_NUMBER_UPDREF            DUK_TVAL_SET_NUMBER_UPDREF_ALT0
#define DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF    DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF_ALT0
#define DUK_TVAL_SET_DOUBLE_UPDREF            DUK_TVAL_SET_DOUBLE_UPDREF_ALT0
#define DUK_TVAL_SET_NAN_UPDREF               DUK_TVAL_SET_NAN_UPDREF_ALT0
#if defined(DUK_USE_FASTINT)
#define DUK_TVAL_SET_I48_UPDREF               DUK_TVAL_SET_I48_UPDREF_ALT0
#define DUK_TVAL_SET_I32_UPDREF               DUK_TVAL_SET_I32_UPDREF_ALT0
#define DUK_TVAL_SET_U32_UPDREF               DUK_TVAL_SET_U32_UPDREF_ALT0
#else
#define DUK_TVAL_SET_I48_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF  /* XXX: fast-int-to-double */
#define DUK_TVAL_SET_I32_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF
#define DUK_TVAL_SET_U32_UPDREF               DUK_TVAL_SET_DOUBLE_CAST_UPDREF
#endif  /* DUK_USE_FASTINT */
#define DUK_TVAL_SET_FASTINT_UPDREF           DUK_TVAL_SET_I48_UPDREF  /* convenience */
#define DUK_TVAL_SET_LIGHTFUNC_UPDREF         DUK_TVAL_SET_LIGHTFUNC_UPDREF_ALT0
#define DUK_TVAL_SET_STRING_UPDREF            DUK_TVAL_SET_STRING_UPDREF_ALT0
#define DUK_TVAL_SET_OBJECT_UPDREF            DUK_TVAL_SET_OBJECT_UPDREF_ALT0
#define DUK_TVAL_SET_BUFFER_UPDREF            DUK_TVAL_SET_BUFFER_UPDREF_ALT0
#define DUK_TVAL_SET_POINTER_UPDREF           DUK_TVAL_SET_POINTER_UPDREF_ALT0

#define DUK_TVAL_SET_TVAL_UPDREF              DUK_TVAL_SET_TVAL_UPDREF_ALT0
#define DUK_TVAL_SET_TVAL_UPDREF_FAST         DUK_TVAL_SET_TVAL_UPDREF_ALT0
#define DUK_TVAL_SET_TVAL_UPDREF_SLOW         DUK_TVAL_SET_TVAL_UPDREF_ALT0

#endif  /* DUK_USE_REFERENCE_COUNTING */

/*
 *  Some convenience macros that don't have optimized implementations now.
 */

#define DUK_TVAL_SET_TVAL_UPDREF_NORZ(thr,tv_dst,tv_src) do { \
		duk_hthread *duk__thr = (thr); \
		duk_tval *duk__dst = (tv_dst); \
		duk_tval *duk__src = (tv_src); \
		DUK_UNREF(duk__thr); \
		DUK_TVAL_DECREF_NORZ(thr, duk__dst); \
		DUK_TVAL_SET_TVAL(duk__dst, duk__src); \
		DUK_TVAL_INCREF(thr, duk__dst); \
	} while (0)

#define DUK_TVAL_SET_U32_UPDREF_NORZ(thr,tv_dst,val) do { \
		duk_hthread *duk__thr = (thr); \
		duk_tval *duk__dst = (tv_dst); \
		duk_uint32_t duk__val = (duk_uint32_t) (val); \
		DUK_UNREF(duk__thr); \
		DUK_TVAL_DECREF_NORZ(thr, duk__dst); \
		DUK_TVAL_SET_U32(duk__dst, duk__val); \
	} while (0)

/*
 *  Prototypes
 */

#if defined(DUK_USE_REFERENCE_COUNTING)
#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL_DECL void duk_refzero_check_slow(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_refzero_check_fast(duk_hthread *thr);
#endif
DUK_INTERNAL_DECL void duk_heaphdr_refcount_finalize_norz(duk_heap *heap, duk_heaphdr *hdr);
DUK_INTERNAL_DECL void duk_hobject_refcount_finalize_norz(duk_heap *heap, duk_hobject *h);
#if 0  /* Not needed: fast path handles inline; slow path uses duk_heaphdr_decref() which is needed anyway. */
DUK_INTERNAL_DECL void duk_hstring_decref(duk_hthread *thr, duk_hstring *h);
DUK_INTERNAL_DECL void duk_hstring_decref_norz(duk_hthread *thr, duk_hstring *h);
DUK_INTERNAL_DECL void duk_hbuffer_decref(duk_hthread *thr, duk_hbuffer *h);
DUK_INTERNAL_DECL void duk_hbuffer_decref_norz(duk_hthread *thr, duk_hbuffer *h);
DUK_INTERNAL_DECL void duk_hobject_decref(duk_hthread *thr, duk_hobject *h);
DUK_INTERNAL_DECL void duk_hobject_decref_norz(duk_hthread *thr, duk_hobject *h);
#endif
DUK_INTERNAL_DECL void duk_heaphdr_refzero(duk_hthread *thr, duk_heaphdr *h);
DUK_INTERNAL_DECL void duk_heaphdr_refzero_norz(duk_hthread *thr, duk_heaphdr *h);
#if defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
DUK_INTERNAL_DECL void duk_hstring_refzero(duk_hthread *thr, duk_hstring *h);  /* no 'norz' variant */
DUK_INTERNAL_DECL void duk_hbuffer_refzero(duk_hthread *thr, duk_hbuffer *h);  /* no 'norz' variant */
DUK_INTERNAL_DECL void duk_hobject_refzero(duk_hthread *thr, duk_hobject *h);
DUK_INTERNAL_DECL void duk_hobject_refzero_norz(duk_hthread *thr, duk_hobject *h);
#else
DUK_INTERNAL_DECL void duk_tval_incref(duk_tval *tv);
DUK_INTERNAL_DECL void duk_tval_decref(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL void duk_tval_decref_norz(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL void duk_heaphdr_incref(duk_heaphdr *h);
DUK_INTERNAL_DECL void duk_heaphdr_decref(duk_hthread *thr, duk_heaphdr *h);
DUK_INTERNAL_DECL void duk_heaphdr_decref_norz(duk_hthread *thr, duk_heaphdr *h);
#endif
#else  /* DUK_USE_REFERENCE_COUNTING */
/* no refcounting */
#endif  /* DUK_USE_REFERENCE_COUNTING */

#endif  /* DUK_REFCOUNT_H_INCLUDED */
/* #include duk_api_internal.h */
/*
 *  Internal API calls which have (stack and other) semantics similar
 *  to the public API.
 */

#if !defined(DUK_API_INTERNAL_H_INCLUDED)
#define DUK_API_INTERNAL_H_INCLUDED

/* Inline macro helpers. */
#if defined(DUK_USE_PREFER_SIZE)
#define DUK_INLINE_PERF
#define DUK_ALWAYS_INLINE_PERF
#define DUK_NOINLINE_PERF
#else
#define DUK_INLINE_PERF DUK_INLINE
#define DUK_ALWAYS_INLINE_PERF DUK_ALWAYS_INLINE
#define DUK_NOINLINE_PERF DUK_NOINLINE
#endif

/* Inline macro helpers, for bytecode executor. */
#if defined(DUK_USE_EXEC_PREFER_SIZE)
#define DUK_EXEC_INLINE_PERF
#define DUK_EXEC_ALWAYS_INLINE_PERF
#define DUK_EXEC_NOINLINE_PERF
#else
#define DUK_EXEC_INLINE_PERF DUK_INLINE
#define DUK_EXEC_ALWAYS_INLINE_PERF DUK_ALWAYS_INLINE
#define DUK_EXEC_NOINLINE_PERF DUK_NOINLINE
#endif

/* duk_push_sprintf constants */
#define DUK_PUSH_SPRINTF_INITIAL_SIZE  256L
#define DUK_PUSH_SPRINTF_SANITY_LIMIT  (1L * 1024L * 1024L * 1024L)

/* Flag ORed to err_code to indicate __FILE__ / __LINE__ is not
 * blamed as source of error for error fileName / lineNumber.
 */
#define DUK_ERRCODE_FLAG_NOBLAME_FILELINE  (1L << 24)

/* Current convention is to use duk_size_t for value stack sizes and global indices,
 * and duk_idx_t for local frame indices.
 */
DUK_INTERNAL_DECL void duk_valstack_grow_check_throw(duk_hthread *thr, duk_size_t min_bytes);
DUK_INTERNAL_DECL duk_bool_t duk_valstack_grow_check_nothrow(duk_hthread *thr, duk_size_t min_bytes);
DUK_INTERNAL_DECL void duk_valstack_shrink_check_nothrow(duk_hthread *thr, duk_bool_t snug);

DUK_INTERNAL_DECL void duk_copy_tvals_incref(duk_hthread *thr, duk_tval *tv_dst, duk_tval *tv_src, duk_size_t count);

DUK_INTERNAL_DECL duk_tval *duk_reserve_gap(duk_hthread *thr, duk_idx_t idx_base, duk_idx_t count);

DUK_INTERNAL_DECL void duk_set_top_unsafe(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL void duk_set_top_and_wipe(duk_hthread *thr, duk_idx_t top, duk_idx_t idx_wipe_start);

DUK_INTERNAL_DECL void duk_dup_0(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_dup_1(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_dup_2(duk_hthread *thr);
/* duk_dup_m1() would be same as duk_dup_top() */
DUK_INTERNAL_DECL void duk_dup_m2(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_dup_m3(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_dup_m4(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_remove_unsafe(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL void duk_remove_m2(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_remove_n(duk_hthread *thr, duk_idx_t idx, duk_idx_t count);
DUK_INTERNAL_DECL void duk_remove_n_unsafe(duk_hthread *thr, duk_idx_t idx, duk_idx_t count);

DUK_INTERNAL_DECL duk_int_t duk_get_type_tval(duk_tval *tv);
DUK_INTERNAL_DECL duk_uint_t duk_get_type_mask_tval(duk_tval *tv);

#if defined(DUK_USE_VERBOSE_ERRORS) && defined(DUK_USE_PARANOID_ERRORS)
DUK_INTERNAL_DECL const char *duk_get_type_name(duk_hthread *thr, duk_idx_t idx);
#endif
DUK_INTERNAL_DECL duk_small_uint_t duk_get_class_number(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_tval *duk_get_tval(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_tval *duk_get_tval_or_unused(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_tval *duk_require_tval(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL void duk_push_tval(duk_hthread *thr, duk_tval *tv);

/* Push the current 'this' binding; throw TypeError if binding is not object
 * coercible (CheckObjectCoercible).
 */
DUK_INTERNAL_DECL void duk_push_this_check_object_coercible(duk_hthread *thr);

/* duk_push_this() + CheckObjectCoercible() + duk_to_object() */
DUK_INTERNAL_DECL duk_hobject *duk_push_this_coercible_to_object(duk_hthread *thr);

/* duk_push_this() + CheckObjectCoercible() + duk_to_string() */
DUK_INTERNAL_DECL duk_hstring *duk_push_this_coercible_to_string(duk_hthread *thr);

DUK_INTERNAL_DECL duk_hstring *duk_push_uint_to_hstring(duk_hthread *thr, duk_uint_t i);

/* Get a borrowed duk_tval pointer to the current 'this' binding.  Caller must
 * make sure there's an active callstack entry.  Note that the returned pointer
 * is unstable with regards to side effects.
 */
DUK_INTERNAL_DECL duk_tval *duk_get_borrowed_this_tval(duk_hthread *thr);

/* XXX: add fastint support? */
#define duk_push_u64(thr,val) \
	duk_push_number((thr), (duk_double_t) (val))
#define duk_push_i64(thr,val) \
	duk_push_number((thr), (duk_double_t) (val))

/* duk_push_(u)int() is guaranteed to support at least (un)signed 32-bit range */
#define duk_push_u32(thr,val) \
	duk_push_uint((thr), (duk_uint_t) (val))
#define duk_push_i32(thr,val) \
	duk_push_int((thr), (duk_int_t) (val))

/* sometimes stack and array indices need to go on the stack */
#define duk_push_idx(thr,val) \
	duk_push_int((thr), (duk_int_t) (val))
#define duk_push_uarridx(thr,val) \
	duk_push_uint((thr), (duk_uint_t) (val))
#define duk_push_size_t(thr,val) \
	duk_push_uint((thr), (duk_uint_t) (val))  /* XXX: assumed to fit for now */

DUK_INTERNAL_DECL duk_bool_t duk_is_string_notsymbol(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_bool_t duk_is_callable_tval(duk_hthread *thr, duk_tval *tv);

DUK_INTERNAL_DECL duk_bool_t duk_is_bare_object(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_hstring *duk_get_hstring(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hstring *duk_get_hstring_notsymbol(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL const char *duk_get_string_notsymbol(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hobject *duk_get_hobject(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hbuffer *duk_get_hbuffer(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hthread *duk_get_hthread(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hcompfunc *duk_get_hcompfunc(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hnatfunc *duk_get_hnatfunc(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL void *duk_get_buffer_data_raw(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_len, duk_bool_t throw_flag, duk_bool_t *out_isbuffer);

DUK_INTERNAL_DECL duk_hobject *duk_get_hobject_with_class(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t classnum);

DUK_INTERNAL_DECL duk_hobject *duk_get_hobject_promote_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask);
DUK_INTERNAL_DECL duk_hobject *duk_require_hobject_promote_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask);
DUK_INTERNAL_DECL duk_hobject *duk_require_hobject_accept_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask);
#define duk_require_hobject_promote_lfunc(thr,idx) \
	duk_require_hobject_promote_mask((thr), (idx), DUK_TYPE_MASK_LIGHTFUNC)
#define duk_get_hobject_promote_lfunc(thr,idx) \
	duk_get_hobject_promote_mask((thr), (idx), DUK_TYPE_MASK_LIGHTFUNC)

#if 0  /*unused*/
DUK_INTERNAL_DECL void *duk_get_voidptr(duk_hthread *thr, duk_idx_t idx);
#endif

DUK_INTERNAL_DECL duk_hstring *duk_known_hstring(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hobject *duk_known_hobject(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hbuffer *duk_known_hbuffer(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hcompfunc *duk_known_hcompfunc(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hnatfunc *duk_known_hnatfunc(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_double_t duk_to_number_tval(duk_hthread *thr, duk_tval *tv);

DUK_INTERNAL_DECL duk_hstring *duk_to_hstring(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hstring *duk_to_hstring_m1(duk_hthread *thr);
DUK_INTERNAL_DECL duk_hstring *duk_to_hstring_acceptsymbol(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_hobject *duk_to_hobject(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_double_t duk_to_number_m1(duk_hthread *thr);
DUK_INTERNAL_DECL duk_double_t duk_to_number_m2(duk_hthread *thr);

DUK_INTERNAL_DECL duk_bool_t duk_to_boolean_top_pop(duk_hthread *thr);

#if defined(DUK_USE_DEBUGGER_SUPPORT)  /* only needed by debugger for now */
DUK_INTERNAL_DECL duk_hstring *duk_safe_to_hstring(duk_hthread *thr, duk_idx_t idx);
#endif
DUK_INTERNAL_DECL void duk_push_class_string_tval(duk_hthread *thr, duk_tval *tv, duk_bool_t avoid_side_effects);

DUK_INTERNAL_DECL duk_int_t duk_to_int_clamped_raw(duk_hthread *thr, duk_idx_t idx, duk_int_t minval, duk_int_t maxval, duk_bool_t *out_clamped);  /* out_clamped=NULL, RangeError if outside range */
DUK_INTERNAL_DECL duk_int_t duk_to_int_clamped(duk_hthread *thr, duk_idx_t idx, duk_int_t minval, duk_int_t maxval);
DUK_INTERNAL_DECL duk_int_t duk_to_int_check_range(duk_hthread *thr, duk_idx_t idx, duk_int_t minval, duk_int_t maxval);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL_DECL duk_uint8_t duk_to_uint8clamped(duk_hthread *thr, duk_idx_t idx);
#endif
DUK_INTERNAL_DECL duk_hstring *duk_to_property_key_hstring(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_hstring *duk_require_hstring(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hstring *duk_require_hstring_notsymbol(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL const char *duk_require_lstring_notsymbol(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len);
DUK_INTERNAL_DECL const char *duk_require_string_notsymbol(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hobject *duk_require_hobject(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hbuffer *duk_require_hbuffer(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hthread *duk_require_hthread(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hcompfunc *duk_require_hcompfunc(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL duk_hnatfunc *duk_require_hnatfunc(duk_hthread *thr, duk_idx_t idx);

DUK_INTERNAL_DECL duk_hobject *duk_require_hobject_with_class(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t classnum);

DUK_INTERNAL_DECL void duk_push_hstring(duk_hthread *thr, duk_hstring *h);
DUK_INTERNAL_DECL void duk_push_hstring_stridx(duk_hthread *thr, duk_small_uint_t stridx);
DUK_INTERNAL_DECL void duk_push_hstring_empty(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_push_hobject(duk_hthread *thr, duk_hobject *h);
DUK_INTERNAL_DECL void duk_push_hbuffer(duk_hthread *thr, duk_hbuffer *h);
#define duk_push_hthread(thr,h) \
	duk_push_hobject((thr), (duk_hobject *) (h))
#define duk_push_hnatfunc(thr,h) \
	duk_push_hobject((thr), (duk_hobject *) (h))
DUK_INTERNAL_DECL void duk_push_hobject_bidx(duk_hthread *thr, duk_small_int_t builtin_idx);
DUK_INTERNAL_DECL duk_hobject *duk_push_object_helper(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_small_int_t prototype_bidx);
DUK_INTERNAL_DECL duk_hobject *duk_push_object_helper_proto(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_hobject *proto);
DUK_INTERNAL_DECL duk_hcompfunc *duk_push_hcompfunc(duk_hthread *thr);
DUK_INTERNAL_DECL duk_hboundfunc *duk_push_hboundfunc(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_push_c_function_builtin(duk_hthread *thr, duk_c_function func, duk_int_t nargs);
DUK_INTERNAL_DECL void duk_push_c_function_builtin_noconstruct(duk_hthread *thr, duk_c_function func, duk_int_t nargs);

/* XXX: duk_push_harray() and duk_push_hcompfunc() are inconsistent with
 * duk_push_hobject() etc which don't create a new value.
 */
DUK_INTERNAL_DECL duk_harray *duk_push_harray(duk_hthread *thr);
DUK_INTERNAL_DECL duk_harray *duk_push_harray_with_size(duk_hthread *thr, duk_uint32_t size);
DUK_INTERNAL_DECL duk_tval *duk_push_harray_with_size_outptr(duk_hthread *thr, duk_uint32_t size);

DUK_INTERNAL_DECL void duk_push_string_funcptr(duk_hthread *thr, duk_uint8_t *ptr, duk_size_t sz);
DUK_INTERNAL_DECL void duk_push_lightfunc_name_raw(duk_hthread *thr, duk_c_function func, duk_small_uint_t lf_flags);
DUK_INTERNAL_DECL void duk_push_lightfunc_name(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL void duk_push_lightfunc_tostring(duk_hthread *thr, duk_tval *tv);
#if 0  /* not used yet */
DUK_INTERNAL_DECL void duk_push_hnatfunc_name(duk_hthread *thr, duk_hnatfunc *h);
#endif
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL_DECL duk_hbufobj *duk_push_bufobj_raw(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_small_int_t prototype_bidx);
#endif

DUK_INTERNAL_DECL void *duk_push_fixed_buffer_nozero(duk_hthread *thr, duk_size_t len);
DUK_INTERNAL_DECL void *duk_push_fixed_buffer_zero(duk_hthread *thr, duk_size_t len);

DUK_INTERNAL_DECL const char *duk_push_string_readable(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL const char *duk_push_string_tval_readable(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL const char *duk_push_string_tval_readable_error(duk_hthread *thr, duk_tval *tv);

/* The duk_xxx_prop_stridx_short() variants expect their arguments to be short
 * enough to be packed into a single 32-bit integer argument.  Argument limits
 * vary per call; typically 16 bits are assigned to the signed value stack index
 * and the stridx.  In practice these work well for footprint with constant
 * arguments and such call sites are also easiest to verify to be correct.
 */

DUK_INTERNAL_DECL duk_bool_t duk_get_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);     /* [] -> [val] */
DUK_INTERNAL_DECL duk_bool_t duk_get_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_get_prop_stridx_short(thr,obj_idx,stridx) \
	(DUK_ASSERT_EXPR((duk_int_t) (obj_idx) >= -0x8000L && (duk_int_t) (obj_idx) <= 0x7fffL), \
	 DUK_ASSERT_EXPR((duk_int_t) (stridx) >= 0 && (duk_int_t) (stridx) <= 0xffffL), \
	 duk_get_prop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 16) + ((duk_uint_t) (stridx))))
DUK_INTERNAL_DECL duk_bool_t duk_get_prop_stridx_boolean(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_bool_t *out_has_prop);  /* [] -> [] */

DUK_INTERNAL_DECL duk_bool_t duk_xget_owndataprop(duk_hthread *thr, duk_idx_t obj_idx);
DUK_INTERNAL_DECL duk_bool_t duk_xget_owndataprop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);
DUK_INTERNAL_DECL duk_bool_t duk_xget_owndataprop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_xget_owndataprop_stridx_short(thr,obj_idx,stridx) \
	(DUK_ASSERT_EXPR((duk_int_t) (obj_idx) >= -0x8000L && (duk_int_t) (obj_idx) <= 0x7fffL), \
	 DUK_ASSERT_EXPR((duk_int_t) (stridx) >= 0 && (duk_int_t) (stridx) <= 0xffffL), \
	 duk_xget_owndataprop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 16) + ((duk_uint_t) (stridx))))

DUK_INTERNAL_DECL duk_bool_t duk_put_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);     /* [val] -> [] */
DUK_INTERNAL_DECL duk_bool_t duk_put_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_put_prop_stridx_short(thr,obj_idx,stridx) \
	(DUK_ASSERT_EXPR((duk_int_t) (obj_idx) >= -0x8000L && (duk_int_t) (obj_idx) <= 0x7fffL), \
	 DUK_ASSERT_EXPR((duk_int_t) (stridx) >= 0 && (duk_int_t) (stridx) <= 0xffffL), \
	 duk_put_prop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 16) + ((duk_uint_t) (stridx))))

DUK_INTERNAL_DECL duk_bool_t duk_del_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);     /* [] -> [] */
#if 0  /* Too few call sites to be useful. */
DUK_INTERNAL_DECL duk_bool_t duk_del_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_del_prop_stridx_short(thr,obj_idx,stridx) \
	(DUK_ASSERT_EXPR((obj_idx) >= -0x8000L && (obj_idx) <= 0x7fffL), \
	 DUK_ASSERT_EXPR((stridx) >= 0 && (stridx) <= 0xffffL), \
	 duk_del_prop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 16) + ((duk_uint_t) (stridx))))
#endif
#define duk_del_prop_stridx_short(thr,obj_idx,stridx) \
	duk_del_prop_stridx((thr), (obj_idx), (stridx))

DUK_INTERNAL_DECL duk_bool_t duk_has_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);     /* [] -> [] */
#if 0  /* Too few call sites to be useful. */
DUK_INTERNAL_DECL duk_bool_t duk_has_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_has_prop_stridx_short(thr,obj_idx,stridx) \
	(DUK_ASSERT_EXPR((obj_idx) >= -0x8000L && (obj_idx) <= 0x7fffL), \
	 DUK_ASSERT_EXPR((stridx) >= 0 && (stridx) <= 0xffffL), \
	 duk_has_prop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 16) + ((duk_uint_t) (stridx))))
#endif
#define duk_has_prop_stridx_short(thr,obj_idx,stridx) \
	duk_has_prop_stridx((thr), (obj_idx), (stridx))

DUK_INTERNAL_DECL void duk_xdef_prop(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t desc_flags);  /* [key val] -> [] */

DUK_INTERNAL_DECL void duk_xdef_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx, duk_small_uint_t desc_flags);  /* [val] -> [] */

/* XXX: Because stridx and desc_flags have a limited range, this call could
 * always pack stridx and desc_flags into a single argument.
 */
DUK_INTERNAL_DECL void duk_xdef_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_small_uint_t desc_flags);  /* [val] -> [] */
DUK_INTERNAL_DECL void duk_xdef_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args);
#define duk_xdef_prop_stridx_short(thr,obj_idx,stridx,desc_flags) \
	(DUK_ASSERT_EXPR((duk_int_t) (obj_idx) >= -0x80L && (duk_int_t) (obj_idx) <= 0x7fL), \
	 DUK_ASSERT_EXPR((duk_int_t) (stridx) >= 0 && (duk_int_t) (stridx) <= 0xffffL), \
	 DUK_ASSERT_EXPR((duk_int_t) (desc_flags) >= 0 && (duk_int_t) (desc_flags) <= 0xffL), \
	 duk_xdef_prop_stridx_short_raw((thr), (((duk_uint_t) (obj_idx)) << 24) + (((duk_uint_t) (stridx)) << 8) + (duk_uint_t) (desc_flags)))

#define duk_xdef_prop_wec(thr,obj_idx) \
	duk_xdef_prop((thr), (obj_idx), DUK_PROPDESC_FLAGS_WEC)
#define duk_xdef_prop_index_wec(thr,obj_idx,arr_idx) \
	duk_xdef_prop_index((thr), (obj_idx), (arr_idx), DUK_PROPDESC_FLAGS_WEC)
#define duk_xdef_prop_stridx_wec(thr,obj_idx,stridx) \
	duk_xdef_prop_stridx((thr), (obj_idx), (stridx), DUK_PROPDESC_FLAGS_WEC)
#define duk_xdef_prop_stridx_short_wec(thr,obj_idx,stridx) \
	duk_xdef_prop_stridx_short((thr), (obj_idx), (stridx), DUK_PROPDESC_FLAGS_WEC)

#if 0  /*unused*/
DUK_INTERNAL_DECL void duk_xdef_prop_stridx_builtin(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_small_int_t builtin_idx, duk_small_uint_t desc_flags);  /* [] -> [] */
#endif

DUK_INTERNAL_DECL void duk_xdef_prop_stridx_thrower(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx);  /* [] -> [] */

DUK_INTERNAL_DECL duk_bool_t duk_get_method_stridx(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t stridx);

DUK_INTERNAL_DECL void duk_pack(duk_hthread *thr, duk_idx_t count);
DUK_INTERNAL_DECL duk_idx_t duk_unpack_array_like(duk_hthread *thr, duk_idx_t idx);
#if 0
DUK_INTERNAL_DECL void duk_unpack(duk_hthread *thr);
#endif

DUK_INTERNAL_DECL void duk_push_symbol_descriptive_string(duk_hthread *thr, duk_hstring *h);

DUK_INTERNAL_DECL void duk_resolve_nonbound_function(duk_hthread *thr);

DUK_INTERNAL_DECL duk_idx_t duk_get_top_require_min(duk_hthread *thr, duk_idx_t min_top);
DUK_INTERNAL_DECL duk_idx_t duk_get_top_index_unsafe(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_pop_n_unsafe(duk_hthread *thr, duk_idx_t count);
DUK_INTERNAL_DECL void duk_pop_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_2_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_3_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_n_nodecref_unsafe(duk_hthread *thr, duk_idx_t count);
DUK_INTERNAL_DECL void duk_pop_nodecref_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_2_nodecref_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_3_nodecref_unsafe(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_pop_undefined(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_compact_m1(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_seal_freeze_raw(duk_hthread *thr, duk_idx_t obj_idx, duk_bool_t is_freeze);

DUK_INTERNAL_DECL void duk_insert_undefined(duk_hthread *thr, duk_idx_t idx);
DUK_INTERNAL_DECL void duk_insert_undefined_n(duk_hthread *thr, duk_idx_t idx, duk_idx_t count);

DUK_INTERNAL_DECL void duk_concat_2(duk_hthread *thr);

DUK_INTERNAL_DECL duk_int_t duk_pcall_method_flags(duk_hthread *thr, duk_idx_t nargs, duk_small_uint_t call_flags);

#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL_DECL void duk_to_primitive_ordinary(duk_hthread *thr, duk_idx_t idx, duk_int_t hint);
#endif

DUK_INTERNAL_DECL void duk_clear_prototype(duk_hthread *thr, duk_idx_t idx);

/* Raw internal valstack access macros: access is unsafe so call site
 * must have a guarantee that the index is valid.  When that is the case,
 * using these macro results in faster and smaller code than duk_get_tval().
 * Both 'ctx' and 'idx' are evaluted multiple times, but only for asserts.
 */
#define DUK_ASSERT_VALID_NEGIDX(thr,idx) \
	(DUK_ASSERT_EXPR((duk_int_t) (idx) < 0), DUK_ASSERT_EXPR(duk_is_valid_index((thr), (idx))))
#define DUK_ASSERT_VALID_POSIDX(thr,idx) \
	(DUK_ASSERT_EXPR((duk_int_t) (idx) >= 0), DUK_ASSERT_EXPR(duk_is_valid_index((thr), (idx))))
#define DUK_GET_TVAL_NEGIDX(thr,idx) \
	(DUK_ASSERT_VALID_NEGIDX((thr),(idx)), ((duk_hthread *) (thr))->valstack_top + (idx))
#define DUK_GET_TVAL_POSIDX(thr,idx) \
	(DUK_ASSERT_VALID_POSIDX((thr),(idx)), ((duk_hthread *) (thr))->valstack_bottom + (idx))
#define DUK_GET_HOBJECT_NEGIDX(thr,idx) \
	(DUK_ASSERT_VALID_NEGIDX((thr),(idx)), DUK_TVAL_GET_OBJECT(((duk_hthread *) (thr))->valstack_top + (idx)))
#define DUK_GET_HOBJECT_POSIDX(thr,idx) \
	(DUK_ASSERT_VALID_POSIDX((thr),(idx)), DUK_TVAL_GET_OBJECT(((duk_hthread *) (thr))->valstack_bottom + (idx)))

#define DUK_GET_THIS_TVAL_PTR(thr) \
	(DUK_ASSERT_EXPR((thr)->valstack_bottom > (thr)->valstack), \
	 (thr)->valstack_bottom - 1)

DUK_INTERNAL_DECL duk_double_t duk_time_get_ecmascript_time(duk_hthread *thr);
DUK_INTERNAL_DECL duk_double_t duk_time_get_ecmascript_time_nofrac(duk_hthread *thr);
DUK_INTERNAL_DECL duk_double_t duk_time_get_monotonic_time(duk_hthread *thr);

#endif  /* DUK_API_INTERNAL_H_INCLUDED */
/* #include duk_hstring.h */
/*
 *  Heap string representation.
 *
 *  Strings are byte sequences ordinarily stored in extended UTF-8 format,
 *  allowing values larger than the official UTF-8 range (used internally)
 *  and also allowing UTF-8 encoding of surrogate pairs (CESU-8 format).
 *  Strings may also be invalid UTF-8 altogether which is the case e.g. with
 *  strings used as internal property names and raw buffers converted to
 *  strings.  In such cases the 'clen' field contains an inaccurate value.
 *
 *  ECMAScript requires support for 32-bit long strings.  However, since each
 *  16-bit codepoint can take 3 bytes in CESU-8, this representation can only
 *  support about 1.4G codepoint long strings in extreme cases.  This is not
 *  really a practical issue.
 */

#if !defined(DUK_HSTRING_H_INCLUDED)
#define DUK_HSTRING_H_INCLUDED

/* Impose a maximum string length for now.  Restricted artificially to
 * ensure adding a heap header length won't overflow size_t.  The limit
 * should be synchronized with DUK_HBUFFER_MAX_BYTELEN.
 *
 * E5.1 makes provisions to support strings longer than 4G characters.
 * This limit should be eliminated on 64-bit platforms (and increased
 * closer to maximum support on 32-bit platforms).
 */

#if defined(DUK_USE_STRLEN16)
#define DUK_HSTRING_MAX_BYTELEN                     (0x0000ffffUL)
#else
#define DUK_HSTRING_MAX_BYTELEN                     (0x7fffffffUL)
#endif

/* XXX: could add flags for "is valid CESU-8" (ECMAScript compatible strings),
 * "is valid UTF-8", "is valid extended UTF-8" (internal strings are not,
 * regexp bytecode is), and "contains non-BMP characters".  These are not
 * needed right now.
 */

/* With lowmem builds the high 16 bits of duk_heaphdr are used for other
 * purposes, so this leaves 7 duk_heaphdr flags and 9 duk_hstring flags.
 */
#define DUK_HSTRING_FLAG_ASCII                      DUK_HEAPHDR_USER_FLAG(0)  /* string is ASCII, clen == blen */
#define DUK_HSTRING_FLAG_ARRIDX                     DUK_HEAPHDR_USER_FLAG(1)  /* string is a valid array index */
#define DUK_HSTRING_FLAG_SYMBOL                     DUK_HEAPHDR_USER_FLAG(2)  /* string is a symbol (invalid utf-8) */
#define DUK_HSTRING_FLAG_HIDDEN                     DUK_HEAPHDR_USER_FLAG(3)  /* string is a hidden symbol (implies symbol, Duktape 1.x internal string) */
#define DUK_HSTRING_FLAG_RESERVED_WORD              DUK_HEAPHDR_USER_FLAG(4)  /* string is a reserved word (non-strict) */
#define DUK_HSTRING_FLAG_STRICT_RESERVED_WORD       DUK_HEAPHDR_USER_FLAG(5)  /* string is a reserved word (strict) */
#define DUK_HSTRING_FLAG_EVAL_OR_ARGUMENTS          DUK_HEAPHDR_USER_FLAG(6)  /* string is 'eval' or 'arguments' */
#define DUK_HSTRING_FLAG_EXTDATA                    DUK_HEAPHDR_USER_FLAG(7)  /* string data is external (duk_hstring_external) */
#define DUK_HSTRING_FLAG_PINNED_LITERAL             DUK_HEAPHDR_USER_FLAG(8)  /* string is a literal, and pinned */

#define DUK_HSTRING_HAS_ASCII(x)                    DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ASCII)
#define DUK_HSTRING_HAS_ARRIDX(x)                   DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ARRIDX)
#define DUK_HSTRING_HAS_SYMBOL(x)                   DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_SYMBOL)
#define DUK_HSTRING_HAS_HIDDEN(x)                   DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_HIDDEN)
#define DUK_HSTRING_HAS_RESERVED_WORD(x)            DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_RESERVED_WORD)
#define DUK_HSTRING_HAS_STRICT_RESERVED_WORD(x)     DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_STRICT_RESERVED_WORD)
#define DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(x)        DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EVAL_OR_ARGUMENTS)
#define DUK_HSTRING_HAS_EXTDATA(x)                  DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EXTDATA)
#define DUK_HSTRING_HAS_PINNED_LITERAL(x)           DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_PINNED_LITERAL)

#define DUK_HSTRING_SET_ASCII(x)                    DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ASCII)
#define DUK_HSTRING_SET_ARRIDX(x)                   DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ARRIDX)
#define DUK_HSTRING_SET_SYMBOL(x)                   DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_SYMBOL)
#define DUK_HSTRING_SET_HIDDEN(x)                   DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_HIDDEN)
#define DUK_HSTRING_SET_RESERVED_WORD(x)            DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_RESERVED_WORD)
#define DUK_HSTRING_SET_STRICT_RESERVED_WORD(x)     DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_STRICT_RESERVED_WORD)
#define DUK_HSTRING_SET_EVAL_OR_ARGUMENTS(x)        DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EVAL_OR_ARGUMENTS)
#define DUK_HSTRING_SET_EXTDATA(x)                  DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EXTDATA)
#define DUK_HSTRING_SET_PINNED_LITERAL(x)           DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_PINNED_LITERAL)

#define DUK_HSTRING_CLEAR_ASCII(x)                  DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ASCII)
#define DUK_HSTRING_CLEAR_ARRIDX(x)                 DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_ARRIDX)
#define DUK_HSTRING_CLEAR_SYMBOL(x)                 DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_SYMBOL)
#define DUK_HSTRING_CLEAR_HIDDEN(x)                 DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_HIDDEN)
#define DUK_HSTRING_CLEAR_RESERVED_WORD(x)          DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_RESERVED_WORD)
#define DUK_HSTRING_CLEAR_STRICT_RESERVED_WORD(x)   DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_STRICT_RESERVED_WORD)
#define DUK_HSTRING_CLEAR_EVAL_OR_ARGUMENTS(x)      DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EVAL_OR_ARGUMENTS)
#define DUK_HSTRING_CLEAR_EXTDATA(x)                DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_EXTDATA)
#define DUK_HSTRING_CLEAR_PINNED_LITERAL(x)         DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HSTRING_FLAG_PINNED_LITERAL)

#if 0  /* Slightly smaller code without explicit flag, but explicit flag
        * is very useful when 'clen' is dropped.
        */
#define DUK_HSTRING_IS_ASCII(x)                     (DUK_HSTRING_GET_BYTELEN((x)) == DUK_HSTRING_GET_CHARLEN((x)))
#endif
#define DUK_HSTRING_IS_ASCII(x)                     DUK_HSTRING_HAS_ASCII((x))  /* lazily set! */
#define DUK_HSTRING_IS_EMPTY(x)                     (DUK_HSTRING_GET_BYTELEN((x)) == 0)

#if defined(DUK_USE_STRHASH16)
#define DUK_HSTRING_GET_HASH(x)                     ((x)->hdr.h_flags >> 16)
#define DUK_HSTRING_SET_HASH(x,v) do { \
		(x)->hdr.h_flags = ((x)->hdr.h_flags & 0x0000ffffUL) | ((v) << 16); \
	} while (0)
#else
#define DUK_HSTRING_GET_HASH(x)                     ((x)->hash)
#define DUK_HSTRING_SET_HASH(x,v) do { \
		(x)->hash = (v); \
	} while (0)
#endif

#if defined(DUK_USE_STRLEN16)
#define DUK_HSTRING_GET_BYTELEN(x)                  ((x)->hdr.h_strextra16)
#define DUK_HSTRING_SET_BYTELEN(x,v) do { \
		(x)->hdr.h_strextra16 = (v); \
	} while (0)
#if defined(DUK_USE_HSTRING_CLEN)
#define DUK_HSTRING_GET_CHARLEN(x)                  duk_hstring_get_charlen((x))
#define DUK_HSTRING_SET_CHARLEN(x,v) do { \
		(x)->clen16 = (v); \
	} while (0)
#else
#define DUK_HSTRING_GET_CHARLEN(x)                  duk_hstring_get_charlen((x))
#define DUK_HSTRING_SET_CHARLEN(x,v) do { \
		DUK_ASSERT(0);  /* should never be called */ \
	} while (0)
#endif
#else
#define DUK_HSTRING_GET_BYTELEN(x)                  ((x)->blen)
#define DUK_HSTRING_SET_BYTELEN(x,v) do { \
		(x)->blen = (v); \
	} while (0)
#define DUK_HSTRING_GET_CHARLEN(x)                  duk_hstring_get_charlen((x))
#define DUK_HSTRING_SET_CHARLEN(x,v) do { \
		(x)->clen = (v); \
	} while (0)
#endif

#if defined(DUK_USE_HSTRING_EXTDATA)
#define DUK_HSTRING_GET_EXTDATA(x) \
	((x)->extdata)
#define DUK_HSTRING_GET_DATA(x) \
	(DUK_HSTRING_HAS_EXTDATA((x)) ? \
		DUK_HSTRING_GET_EXTDATA((const duk_hstring_external *) (x)) : ((const duk_uint8_t *) ((x) + 1)))
#else
#define DUK_HSTRING_GET_DATA(x) \
	((const duk_uint8_t *) ((x) + 1))
#endif

#define DUK_HSTRING_GET_DATA_END(x) \
	(DUK_HSTRING_GET_DATA((x)) + (x)->blen)

/* Marker value; in E5 2^32-1 is not a valid array index (2^32-2 is highest
 * valid).
 */
#define DUK_HSTRING_NO_ARRAY_INDEX  (0xffffffffUL)

#if defined(DUK_USE_HSTRING_ARRIDX)
#define DUK_HSTRING_GET_ARRIDX_FAST(h)  ((h)->arridx)
#define DUK_HSTRING_GET_ARRIDX_SLOW(h)  ((h)->arridx)
#else
/* Get array index related to string (or return DUK_HSTRING_NO_ARRAY_INDEX);
 * avoids helper call if string has no array index value.
 */
#define DUK_HSTRING_GET_ARRIDX_FAST(h)  \
	(DUK_HSTRING_HAS_ARRIDX((h)) ? duk_js_to_arrayindex_hstring_fast_known((h)) : DUK_HSTRING_NO_ARRAY_INDEX)

/* Slower but more compact variant. */
#define DUK_HSTRING_GET_ARRIDX_SLOW(h)  \
	(duk_js_to_arrayindex_hstring_fast((h)))
#endif

/* XXX: these actually fit into duk_hstring */
#define DUK_SYMBOL_TYPE_HIDDEN 0
#define DUK_SYMBOL_TYPE_GLOBAL 1
#define DUK_SYMBOL_TYPE_LOCAL 2
#define DUK_SYMBOL_TYPE_WELLKNOWN 3

/* Assertion for duk_hstring validity. */
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hstring_assert_valid(duk_hstring *h);
#define DUK_HSTRING_ASSERT_VALID(h)  do { duk_hstring_assert_valid((h)); } while (0)
#else
#define DUK_HSTRING_ASSERT_VALID(h)  do {} while (0)
#endif

/*
 *  Misc
 */

struct duk_hstring {
	/* Smaller heaphdr than for other objects, because strings are held
	 * in string intern table which requires no link pointers.  Much of
	 * the 32-bit flags field is unused by flags, so we can stuff a 16-bit
	 * field in there.
	 */
	duk_heaphdr_string hdr;

	/* String hash. */
#if defined(DUK_USE_STRHASH16)
	/* If 16-bit hash is in use, stuff it into duk_heaphdr_string flags. */
#else
	duk_uint32_t hash;
#endif

	/* Precomputed array index (or DUK_HSTRING_NO_ARRAY_INDEX). */
#if defined(DUK_USE_HSTRING_ARRIDX)
	duk_uarridx_t arridx;
#endif

	/* Length in bytes (not counting NUL term). */
#if defined(DUK_USE_STRLEN16)
	/* placed in duk_heaphdr_string */
#else
	duk_uint32_t blen;
#endif

	/* Length in codepoints (must be E5 compatible). */
#if defined(DUK_USE_STRLEN16)
#if defined(DUK_USE_HSTRING_CLEN)
	duk_uint16_t clen16;
#else
	/* computed live */
#endif
#else
	duk_uint32_t clen;
#endif

	/*
	 *  String data of 'blen+1' bytes follows (+1 for NUL termination
	 *  convenience for C API).  No alignment needs to be guaranteed
	 *  for strings, but fields above should guarantee alignment-by-4
	 *  (but not alignment-by-8).
	 */
};

/* The external string struct is defined even when the feature is inactive. */
struct duk_hstring_external {
	duk_hstring str;

	/*
	 *  For an external string, the NUL-terminated string data is stored
	 *  externally.  The user must guarantee that data behind this pointer
	 *  doesn't change while it's used.
	 */

	const duk_uint8_t *extdata;
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL duk_ucodepoint_t duk_hstring_char_code_at_raw(duk_hthread *thr, duk_hstring *h, duk_uint_t pos, duk_bool_t surrogate_aware);
DUK_INTERNAL_DECL duk_bool_t duk_hstring_equals_ascii_cstring(duk_hstring *h, const char *cstr);
DUK_INTERNAL_DECL duk_size_t duk_hstring_get_charlen(duk_hstring *h);
#if !defined(DUK_USE_HSTRING_LAZY_CLEN)
DUK_INTERNAL_DECL void duk_hstring_init_charlen(duk_hstring *h);
#endif

#endif  /* DUK_HSTRING_H_INCLUDED */
/* #include duk_hobject.h */
/*
 *  Heap object representation.
 *
 *  Heap objects are used for ECMAScript objects, arrays, and functions,
 *  but also for internal control like declarative and object environment
 *  records.  Compiled functions, native functions, and threads are also
 *  objects but with an extended C struct.
 *
 *  Objects provide the required ECMAScript semantics and exotic behaviors
 *  especially for property access.
 *
 *  Properties are stored in three conceptual parts:
 *
 *    1. A linear 'entry part' contains ordered key-value-attributes triples
 *       and is the main method of string properties.
 *
 *    2. An optional linear 'array part' is used for array objects to store a
 *       (dense) range of [0,N[ array indexed entries with default attributes
 *       (writable, enumerable, configurable).  If the array part would become
 *       sparse or non-default attributes are required, the array part is
 *       abandoned and moved to the 'entry part'.
 *
 *    3. An optional 'hash part' is used to optimize lookups of the entry
 *       part; it is used only for objects with sufficiently many properties
 *       and can be abandoned without loss of information.
 *
 *  These three conceptual parts are stored in a single memory allocated area.
 *  This minimizes memory allocation overhead but also means that all three
 *  parts are resized together, and makes property access a bit complicated.
 */

#if !defined(DUK_HOBJECT_H_INCLUDED)
#define DUK_HOBJECT_H_INCLUDED

/* Object flags.  Make sure this stays in sync with debugger object
 * inspection code.
 */

/* XXX: some flags are object subtype specific (e.g. common to all function
 * subtypes, duk_harray, etc) and could be reused for different subtypes.
 */
#define DUK_HOBJECT_FLAG_EXTENSIBLE            DUK_HEAPHDR_USER_FLAG(0)   /* object is extensible */
#define DUK_HOBJECT_FLAG_CONSTRUCTABLE         DUK_HEAPHDR_USER_FLAG(1)   /* object is constructable */
#define DUK_HOBJECT_FLAG_CALLABLE              DUK_HEAPHDR_USER_FLAG(2)   /* object is callable */
#define DUK_HOBJECT_FLAG_BOUNDFUNC             DUK_HEAPHDR_USER_FLAG(3)   /* object established using Function.prototype.bind() */
#define DUK_HOBJECT_FLAG_COMPFUNC              DUK_HEAPHDR_USER_FLAG(4)   /* object is a compiled function (duk_hcompfunc) */
#define DUK_HOBJECT_FLAG_NATFUNC               DUK_HEAPHDR_USER_FLAG(5)   /* object is a native function (duk_hnatfunc) */
#define DUK_HOBJECT_FLAG_BUFOBJ                DUK_HEAPHDR_USER_FLAG(6)   /* object is a buffer object (duk_hbufobj) (always exotic) */
#define DUK_HOBJECT_FLAG_FASTREFS              DUK_HEAPHDR_USER_FLAG(7)   /* object has no fields needing DECREF/marking beyond base duk_hobject header */
#define DUK_HOBJECT_FLAG_ARRAY_PART            DUK_HEAPHDR_USER_FLAG(8)   /* object has an array part (a_size may still be 0) */
#define DUK_HOBJECT_FLAG_STRICT                DUK_HEAPHDR_USER_FLAG(9)   /* function: function object is strict */
#define DUK_HOBJECT_FLAG_NOTAIL                DUK_HEAPHDR_USER_FLAG(10)  /* function: function must not be tail called */
#define DUK_HOBJECT_FLAG_NEWENV                DUK_HEAPHDR_USER_FLAG(11)  /* function: create new environment when called (see duk_hcompfunc) */
#define DUK_HOBJECT_FLAG_NAMEBINDING           DUK_HEAPHDR_USER_FLAG(12)  /* function: create binding for func name (function templates only, used for named function expressions) */
#define DUK_HOBJECT_FLAG_CREATEARGS            DUK_HEAPHDR_USER_FLAG(13)  /* function: create an arguments object on function call */
#define DUK_HOBJECT_FLAG_HAVE_FINALIZER        DUK_HEAPHDR_USER_FLAG(14)  /* object has a callable (own) finalizer property */
#define DUK_HOBJECT_FLAG_EXOTIC_ARRAY          DUK_HEAPHDR_USER_FLAG(15)  /* 'Array' object, array length and index exotic behavior */
#define DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ      DUK_HEAPHDR_USER_FLAG(16)  /* 'String' object, array index exotic behavior */
#define DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS      DUK_HEAPHDR_USER_FLAG(17)  /* 'Arguments' object and has arguments exotic behavior (non-strict callee) */
#define DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ       DUK_HEAPHDR_USER_FLAG(18)  /* 'Proxy' object */
#define DUK_HOBJECT_FLAG_SPECIAL_CALL          DUK_HEAPHDR_USER_FLAG(19)  /* special casing in call behavior, for .call(), .apply(), etc. */

#define DUK_HOBJECT_FLAG_CLASS_BASE            DUK_HEAPHDR_USER_FLAG_NUMBER(20)
#define DUK_HOBJECT_FLAG_CLASS_BITS            5

#define DUK_HOBJECT_GET_CLASS_NUMBER(h)        \
	DUK_HEAPHDR_GET_FLAG_RANGE(&(h)->hdr, DUK_HOBJECT_FLAG_CLASS_BASE, DUK_HOBJECT_FLAG_CLASS_BITS)
#define DUK_HOBJECT_SET_CLASS_NUMBER(h,v)      \
	DUK_HEAPHDR_SET_FLAG_RANGE(&(h)->hdr, DUK_HOBJECT_FLAG_CLASS_BASE, DUK_HOBJECT_FLAG_CLASS_BITS, (v))

#define DUK_HOBJECT_GET_CLASS_MASK(h)          \
	(1UL << DUK_HEAPHDR_GET_FLAG_RANGE(&(h)->hdr, DUK_HOBJECT_FLAG_CLASS_BASE, DUK_HOBJECT_FLAG_CLASS_BITS))

/* Macro for creating flag initializer from a class number.
 * Unsigned type cast is needed to avoid warnings about coercing
 * a signed integer to an unsigned one; the largest class values
 * have the highest bit (bit 31) set which causes this.
 */
#define DUK_HOBJECT_CLASS_AS_FLAGS(v)          (((duk_uint_t) (v)) << DUK_HOBJECT_FLAG_CLASS_BASE)

/* E5 Section 8.6.2 + custom classes */
#define DUK_HOBJECT_CLASS_NONE                 0
#define DUK_HOBJECT_CLASS_OBJECT               1
#define DUK_HOBJECT_CLASS_ARRAY                2
#define DUK_HOBJECT_CLASS_FUNCTION             3
#define DUK_HOBJECT_CLASS_ARGUMENTS            4
#define DUK_HOBJECT_CLASS_BOOLEAN              5
#define DUK_HOBJECT_CLASS_DATE                 6
#define DUK_HOBJECT_CLASS_ERROR                7
#define DUK_HOBJECT_CLASS_JSON                 8
#define DUK_HOBJECT_CLASS_MATH                 9
#define DUK_HOBJECT_CLASS_NUMBER               10
#define DUK_HOBJECT_CLASS_REGEXP               11
#define DUK_HOBJECT_CLASS_STRING               12
#define DUK_HOBJECT_CLASS_GLOBAL               13
#define DUK_HOBJECT_CLASS_SYMBOL               14
#define DUK_HOBJECT_CLASS_OBJENV               15  /* custom */
#define DUK_HOBJECT_CLASS_DECENV               16  /* custom */
#define DUK_HOBJECT_CLASS_POINTER              17  /* custom */
#define DUK_HOBJECT_CLASS_THREAD               18  /* custom; implies DUK_HOBJECT_IS_THREAD */
#define DUK_HOBJECT_CLASS_BUFOBJ_MIN           19
#define DUK_HOBJECT_CLASS_ARRAYBUFFER          19  /* implies DUK_HOBJECT_IS_BUFOBJ */
#define DUK_HOBJECT_CLASS_DATAVIEW             20
#define DUK_HOBJECT_CLASS_INT8ARRAY            21
#define DUK_HOBJECT_CLASS_UINT8ARRAY           22
#define DUK_HOBJECT_CLASS_UINT8CLAMPEDARRAY    23
#define DUK_HOBJECT_CLASS_INT16ARRAY           24
#define DUK_HOBJECT_CLASS_UINT16ARRAY          25
#define DUK_HOBJECT_CLASS_INT32ARRAY           26
#define DUK_HOBJECT_CLASS_UINT32ARRAY          27
#define DUK_HOBJECT_CLASS_FLOAT32ARRAY         28
#define DUK_HOBJECT_CLASS_FLOAT64ARRAY         29
#define DUK_HOBJECT_CLASS_BUFOBJ_MAX           29
#define DUK_HOBJECT_CLASS_MAX                  29

/* Class masks. */
#define DUK_HOBJECT_CMASK_ALL                  ((1UL << (DUK_HOBJECT_CLASS_MAX + 1)) - 1UL)
#define DUK_HOBJECT_CMASK_NONE                 (1UL << DUK_HOBJECT_CLASS_NONE)
#define DUK_HOBJECT_CMASK_ARGUMENTS            (1UL << DUK_HOBJECT_CLASS_ARGUMENTS)
#define DUK_HOBJECT_CMASK_ARRAY                (1UL << DUK_HOBJECT_CLASS_ARRAY)
#define DUK_HOBJECT_CMASK_BOOLEAN              (1UL << DUK_HOBJECT_CLASS_BOOLEAN)
#define DUK_HOBJECT_CMASK_DATE                 (1UL << DUK_HOBJECT_CLASS_DATE)
#define DUK_HOBJECT_CMASK_ERROR                (1UL << DUK_HOBJECT_CLASS_ERROR)
#define DUK_HOBJECT_CMASK_FUNCTION             (1UL << DUK_HOBJECT_CLASS_FUNCTION)
#define DUK_HOBJECT_CMASK_JSON                 (1UL << DUK_HOBJECT_CLASS_JSON)
#define DUK_HOBJECT_CMASK_MATH                 (1UL << DUK_HOBJECT_CLASS_MATH)
#define DUK_HOBJECT_CMASK_NUMBER               (1UL << DUK_HOBJECT_CLASS_NUMBER)
#define DUK_HOBJECT_CMASK_OBJECT               (1UL << DUK_HOBJECT_CLASS_OBJECT)
#define DUK_HOBJECT_CMASK_REGEXP               (1UL << DUK_HOBJECT_CLASS_REGEXP)
#define DUK_HOBJECT_CMASK_STRING               (1UL << DUK_HOBJECT_CLASS_STRING)
#define DUK_HOBJECT_CMASK_GLOBAL               (1UL << DUK_HOBJECT_CLASS_GLOBAL)
#define DUK_HOBJECT_CMASK_SYMBOL               (1UL << DUK_HOBJECT_CLASS_SYMBOL)
#define DUK_HOBJECT_CMASK_OBJENV               (1UL << DUK_HOBJECT_CLASS_OBJENV)
#define DUK_HOBJECT_CMASK_DECENV               (1UL << DUK_HOBJECT_CLASS_DECENV)
#define DUK_HOBJECT_CMASK_POINTER              (1UL << DUK_HOBJECT_CLASS_POINTER)
#define DUK_HOBJECT_CMASK_ARRAYBUFFER          (1UL << DUK_HOBJECT_CLASS_ARRAYBUFFER)
#define DUK_HOBJECT_CMASK_DATAVIEW             (1UL << DUK_HOBJECT_CLASS_DATAVIEW)
#define DUK_HOBJECT_CMASK_INT8ARRAY            (1UL << DUK_HOBJECT_CLASS_INT8ARRAY)
#define DUK_HOBJECT_CMASK_UINT8ARRAY           (1UL << DUK_HOBJECT_CLASS_UINT8ARRAY)
#define DUK_HOBJECT_CMASK_UINT8CLAMPEDARRAY    (1UL << DUK_HOBJECT_CLASS_UINT8CLAMPEDARRAY)
#define DUK_HOBJECT_CMASK_INT16ARRAY           (1UL << DUK_HOBJECT_CLASS_INT16ARRAY)
#define DUK_HOBJECT_CMASK_UINT16ARRAY          (1UL << DUK_HOBJECT_CLASS_UINT16ARRAY)
#define DUK_HOBJECT_CMASK_INT32ARRAY           (1UL << DUK_HOBJECT_CLASS_INT32ARRAY)
#define DUK_HOBJECT_CMASK_UINT32ARRAY          (1UL << DUK_HOBJECT_CLASS_UINT32ARRAY)
#define DUK_HOBJECT_CMASK_FLOAT32ARRAY         (1UL << DUK_HOBJECT_CLASS_FLOAT32ARRAY)
#define DUK_HOBJECT_CMASK_FLOAT64ARRAY         (1UL << DUK_HOBJECT_CLASS_FLOAT64ARRAY)

#define DUK_HOBJECT_CMASK_ALL_BUFOBJS \
	(DUK_HOBJECT_CMASK_ARRAYBUFFER | \
	 DUK_HOBJECT_CMASK_DATAVIEW | \
	 DUK_HOBJECT_CMASK_INT8ARRAY | \
	 DUK_HOBJECT_CMASK_UINT8ARRAY | \
	 DUK_HOBJECT_CMASK_UINT8CLAMPEDARRAY | \
	 DUK_HOBJECT_CMASK_INT16ARRAY | \
	 DUK_HOBJECT_CMASK_UINT16ARRAY | \
	 DUK_HOBJECT_CMASK_INT32ARRAY | \
	 DUK_HOBJECT_CMASK_UINT32ARRAY | \
	 DUK_HOBJECT_CMASK_FLOAT32ARRAY | \
	 DUK_HOBJECT_CMASK_FLOAT64ARRAY)

#define DUK_HOBJECT_IS_OBJENV(h)               (DUK_HOBJECT_GET_CLASS_NUMBER((h)) == DUK_HOBJECT_CLASS_OBJENV)
#define DUK_HOBJECT_IS_DECENV(h)               (DUK_HOBJECT_GET_CLASS_NUMBER((h)) == DUK_HOBJECT_CLASS_DECENV)
#define DUK_HOBJECT_IS_ENV(h)                  (DUK_HOBJECT_IS_OBJENV((h)) || DUK_HOBJECT_IS_DECENV((h)))
#define DUK_HOBJECT_IS_ARRAY(h)                DUK_HOBJECT_HAS_EXOTIC_ARRAY((h))  /* Rely on class Array <=> exotic Array */
#define DUK_HOBJECT_IS_BOUNDFUNC(h)            DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BOUNDFUNC)
#define DUK_HOBJECT_IS_COMPFUNC(h)             DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_COMPFUNC)
#define DUK_HOBJECT_IS_NATFUNC(h)              DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NATFUNC)
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#define DUK_HOBJECT_IS_BUFOBJ(h)               DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BUFOBJ)
#else
#define DUK_HOBJECT_IS_BUFOBJ(h)               0
#endif
#define DUK_HOBJECT_IS_THREAD(h)               (DUK_HOBJECT_GET_CLASS_NUMBER((h)) == DUK_HOBJECT_CLASS_THREAD)
#if defined(DUK_USE_ES6_PROXY)
#define DUK_HOBJECT_IS_PROXY(h)                DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ((h))
#else
#define DUK_HOBJECT_IS_PROXY(h)                0
#endif

#define DUK_HOBJECT_IS_NONBOUND_FUNCTION(h)    DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, \
                                                        DUK_HOBJECT_FLAG_COMPFUNC | \
                                                        DUK_HOBJECT_FLAG_NATFUNC)

#define DUK_HOBJECT_IS_FUNCTION(h)             DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, \
                                                        DUK_HOBJECT_FLAG_BOUNDFUNC | \
                                                        DUK_HOBJECT_FLAG_COMPFUNC | \
                                                        DUK_HOBJECT_FLAG_NATFUNC)

#define DUK_HOBJECT_IS_CALLABLE(h)             DUK_HOBJECT_HAS_CALLABLE((h))

/* Object has any exotic behavior(s). */
#define DUK_HOBJECT_EXOTIC_BEHAVIOR_FLAGS      (DUK_HOBJECT_FLAG_EXOTIC_ARRAY | \
                                                DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS | \
                                                DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ | \
                                                DUK_HOBJECT_FLAG_BUFOBJ | \
                                                DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ)
#define DUK_HOBJECT_HAS_EXOTIC_BEHAVIOR(h)     DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_EXOTIC_BEHAVIOR_FLAGS)

/* Object has any virtual properties (not counting Proxy behavior). */
#define DUK_HOBJECT_VIRTUAL_PROPERTY_FLAGS     (DUK_HOBJECT_FLAG_EXOTIC_ARRAY | \
                                                DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ | \
                                                DUK_HOBJECT_FLAG_BUFOBJ)
#define DUK_HOBJECT_HAS_VIRTUAL_PROPERTIES(h)  DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_VIRTUAL_PROPERTY_FLAGS)

#define DUK_HOBJECT_HAS_EXTENSIBLE(h)          DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXTENSIBLE)
#define DUK_HOBJECT_HAS_CONSTRUCTABLE(h)       DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CONSTRUCTABLE)
#define DUK_HOBJECT_HAS_CALLABLE(h)            DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CALLABLE)
#define DUK_HOBJECT_HAS_BOUNDFUNC(h)           DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BOUNDFUNC)
#define DUK_HOBJECT_HAS_COMPFUNC(h)            DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_COMPFUNC)
#define DUK_HOBJECT_HAS_NATFUNC(h)             DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NATFUNC)
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#define DUK_HOBJECT_HAS_BUFOBJ(h)              DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BUFOBJ)
#else
#define DUK_HOBJECT_HAS_BUFOBJ(h)              0
#endif
#define DUK_HOBJECT_HAS_FASTREFS(h)            DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_FASTREFS)
#define DUK_HOBJECT_HAS_ARRAY_PART(h)          DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_ARRAY_PART)
#define DUK_HOBJECT_HAS_STRICT(h)              DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_STRICT)
#define DUK_HOBJECT_HAS_NOTAIL(h)              DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NOTAIL)
#define DUK_HOBJECT_HAS_NEWENV(h)              DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NEWENV)
#define DUK_HOBJECT_HAS_NAMEBINDING(h)         DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NAMEBINDING)
#define DUK_HOBJECT_HAS_CREATEARGS(h)          DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CREATEARGS)
#define DUK_HOBJECT_HAS_HAVE_FINALIZER(h)      DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_HAVE_FINALIZER)
#define DUK_HOBJECT_HAS_EXOTIC_ARRAY(h)        DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARRAY)
#define DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(h)    DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ)
#define DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(h)    DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS)
#if defined(DUK_USE_ES6_PROXY)
#define DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h)     DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ)
#else
#define DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h)     0
#endif
#define DUK_HOBJECT_HAS_SPECIAL_CALL(h)        DUK_HEAPHDR_CHECK_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_SPECIAL_CALL)

#define DUK_HOBJECT_SET_EXTENSIBLE(h)          DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXTENSIBLE)
#define DUK_HOBJECT_SET_CONSTRUCTABLE(h)       DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CONSTRUCTABLE)
#define DUK_HOBJECT_SET_CALLABLE(h)            DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CALLABLE)
#define DUK_HOBJECT_SET_BOUNDFUNC(h)           DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BOUNDFUNC)
#define DUK_HOBJECT_SET_COMPFUNC(h)            DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_COMPFUNC)
#define DUK_HOBJECT_SET_NATFUNC(h)             DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NATFUNC)
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#define DUK_HOBJECT_SET_BUFOBJ(h)              DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BUFOBJ)
#endif
#define DUK_HOBJECT_SET_FASTREFS(h)            DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_FASTREFS)
#define DUK_HOBJECT_SET_ARRAY_PART(h)          DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_ARRAY_PART)
#define DUK_HOBJECT_SET_STRICT(h)              DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_STRICT)
#define DUK_HOBJECT_SET_NOTAIL(h)              DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NOTAIL)
#define DUK_HOBJECT_SET_NEWENV(h)              DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NEWENV)
#define DUK_HOBJECT_SET_NAMEBINDING(h)         DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NAMEBINDING)
#define DUK_HOBJECT_SET_CREATEARGS(h)          DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CREATEARGS)
#define DUK_HOBJECT_SET_HAVE_FINALIZER(h)      DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_HAVE_FINALIZER)
#define DUK_HOBJECT_SET_EXOTIC_ARRAY(h)        DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARRAY)
#define DUK_HOBJECT_SET_EXOTIC_STRINGOBJ(h)    DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ)
#define DUK_HOBJECT_SET_EXOTIC_ARGUMENTS(h)    DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS)
#if defined(DUK_USE_ES6_PROXY)
#define DUK_HOBJECT_SET_EXOTIC_PROXYOBJ(h)     DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ)
#endif
#define DUK_HOBJECT_SET_SPECIAL_CALL(h)        DUK_HEAPHDR_SET_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_SPECIAL_CALL)

#define DUK_HOBJECT_CLEAR_EXTENSIBLE(h)        DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXTENSIBLE)
#define DUK_HOBJECT_CLEAR_CONSTRUCTABLE(h)     DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CONSTRUCTABLE)
#define DUK_HOBJECT_CLEAR_CALLABLE(h)          DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CALLABLE)
#define DUK_HOBJECT_CLEAR_BOUNDFUNC(h)         DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BOUNDFUNC)
#define DUK_HOBJECT_CLEAR_COMPFUNC(h)          DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_COMPFUNC)
#define DUK_HOBJECT_CLEAR_NATFUNC(h)           DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NATFUNC)
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#define DUK_HOBJECT_CLEAR_BUFOBJ(h)            DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_BUFOBJ)
#endif
#define DUK_HOBJECT_CLEAR_FASTREFS(h)          DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_FASTREFS)
#define DUK_HOBJECT_CLEAR_ARRAY_PART(h)        DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_ARRAY_PART)
#define DUK_HOBJECT_CLEAR_STRICT(h)            DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_STRICT)
#define DUK_HOBJECT_CLEAR_NOTAIL(h)            DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NOTAIL)
#define DUK_HOBJECT_CLEAR_NEWENV(h)            DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NEWENV)
#define DUK_HOBJECT_CLEAR_NAMEBINDING(h)       DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_NAMEBINDING)
#define DUK_HOBJECT_CLEAR_CREATEARGS(h)        DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_CREATEARGS)
#define DUK_HOBJECT_CLEAR_HAVE_FINALIZER(h)    DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_HAVE_FINALIZER)
#define DUK_HOBJECT_CLEAR_EXOTIC_ARRAY(h)      DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARRAY)
#define DUK_HOBJECT_CLEAR_EXOTIC_STRINGOBJ(h)  DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ)
#define DUK_HOBJECT_CLEAR_EXOTIC_ARGUMENTS(h)  DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS)
#if defined(DUK_USE_ES6_PROXY)
#define DUK_HOBJECT_CLEAR_EXOTIC_PROXYOBJ(h)   DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ)
#endif
#define DUK_HOBJECT_CLEAR_SPECIAL_CALL(h)      DUK_HEAPHDR_CLEAR_FLAG_BITS(&(h)->hdr, DUK_HOBJECT_FLAG_SPECIAL_CALL)

/* Object can/cannot use FASTREFS, i.e. has no strong reference fields beyond
 * duk_hobject base header.  This is used just for asserts so doesn't need to
 * be optimized.
 */
#define DUK_HOBJECT_PROHIBITS_FASTREFS(h) \
	(DUK_HOBJECT_IS_COMPFUNC((h)) || DUK_HOBJECT_IS_DECENV((h)) || DUK_HOBJECT_IS_OBJENV((h)) || \
	 DUK_HOBJECT_IS_BUFOBJ((h)) || DUK_HOBJECT_IS_THREAD((h)) || DUK_HOBJECT_IS_PROXY((h)) || \
	 DUK_HOBJECT_IS_BOUNDFUNC((h)))
#define DUK_HOBJECT_ALLOWS_FASTREFS(h) (!DUK_HOBJECT_PROHIBITS_FASTREFS((h)))

/* Flags used for property attributes in duk_propdesc and packed flags.
 * Must fit into 8 bits.
 */
#define DUK_PROPDESC_FLAG_WRITABLE              (1U << 0)    /* E5 Section 8.6.1 */
#define DUK_PROPDESC_FLAG_ENUMERABLE            (1U << 1)    /* E5 Section 8.6.1 */
#define DUK_PROPDESC_FLAG_CONFIGURABLE          (1U << 2)    /* E5 Section 8.6.1 */
#define DUK_PROPDESC_FLAG_ACCESSOR              (1U << 3)    /* accessor */
#define DUK_PROPDESC_FLAG_VIRTUAL               (1U << 4)    /* property is virtual: used in duk_propdesc, never stored
                                                             * (used by e.g. buffer virtual properties)
                                                             */
#define DUK_PROPDESC_FLAGS_MASK                 (DUK_PROPDESC_FLAG_WRITABLE | \
                                                 DUK_PROPDESC_FLAG_ENUMERABLE | \
                                                 DUK_PROPDESC_FLAG_CONFIGURABLE | \
                                                 DUK_PROPDESC_FLAG_ACCESSOR)

/* Additional flags which are passed in the same flags argument as property
 * flags but are not stored in object properties.
 */
#define DUK_PROPDESC_FLAG_NO_OVERWRITE          (1U << 4)    /* internal define property: skip write silently if exists */

/* Convenience defines for property attributes. */
#define DUK_PROPDESC_FLAGS_NONE                 0
#define DUK_PROPDESC_FLAGS_W                    (DUK_PROPDESC_FLAG_WRITABLE)
#define DUK_PROPDESC_FLAGS_E                    (DUK_PROPDESC_FLAG_ENUMERABLE)
#define DUK_PROPDESC_FLAGS_C                    (DUK_PROPDESC_FLAG_CONFIGURABLE)
#define DUK_PROPDESC_FLAGS_WE                   (DUK_PROPDESC_FLAG_WRITABLE | DUK_PROPDESC_FLAG_ENUMERABLE)
#define DUK_PROPDESC_FLAGS_WC                   (DUK_PROPDESC_FLAG_WRITABLE | DUK_PROPDESC_FLAG_CONFIGURABLE)
#define DUK_PROPDESC_FLAGS_EC                   (DUK_PROPDESC_FLAG_ENUMERABLE | DUK_PROPDESC_FLAG_CONFIGURABLE)
#define DUK_PROPDESC_FLAGS_WEC                  (DUK_PROPDESC_FLAG_WRITABLE | \
                                                 DUK_PROPDESC_FLAG_ENUMERABLE | \
                                                 DUK_PROPDESC_FLAG_CONFIGURABLE)

/* Flags for duk_hobject_get_own_propdesc() and variants. */
#define DUK_GETDESC_FLAG_PUSH_VALUE          (1U << 0)  /* push value to stack */
#define DUK_GETDESC_FLAG_IGNORE_PROTOLOOP    (1U << 1)  /* don't throw for prototype loop */

/*
 *  Macro for object validity check
 *
 *  Assert for currently guaranteed relations between flags, for instance.
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hobject_assert_valid(duk_hobject *h);
#define DUK_HOBJECT_ASSERT_VALID(h)  do { duk_hobject_assert_valid((h)); } while (0)
#else
#define DUK_HOBJECT_ASSERT_VALID(h)  do {} while (0)
#endif

/*
 *  Macros to access the 'props' allocation.
 */

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HOBJECT_GET_PROPS(heap,h) \
	((duk_uint8_t *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, ((duk_heaphdr *) (h))->h_extra16))
#define DUK_HOBJECT_SET_PROPS(heap,h,x) do { \
		((duk_heaphdr *) (h))->h_extra16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (x)); \
	} while (0)
#else
#define DUK_HOBJECT_GET_PROPS(heap,h) \
	((h)->props)
#define DUK_HOBJECT_SET_PROPS(heap,h,x) do { \
		(h)->props = (duk_uint8_t *) (x); \
	} while (0)
#endif

#if defined(DUK_USE_HOBJECT_LAYOUT_1)
/* LAYOUT 1 */
#define DUK_HOBJECT_E_GET_KEY_BASE(heap,h) \
	((duk_hstring **) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) \
	))
#define DUK_HOBJECT_E_GET_VALUE_BASE(heap,h) \
	((duk_propvalue *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * sizeof(duk_hstring *) \
	))
#define DUK_HOBJECT_E_GET_FLAGS_BASE(heap,h) \
	((duk_uint8_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue)) \
	))
#define DUK_HOBJECT_A_GET_BASE(heap,h) \
	((duk_tval *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) \
	))
#define DUK_HOBJECT_H_GET_BASE(heap,h) \
	((duk_uint32_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) + \
			DUK_HOBJECT_GET_ASIZE((h)) * sizeof(duk_tval) \
	))
#define DUK_HOBJECT_P_COMPUTE_SIZE(n_ent,n_arr,n_hash) \
	( \
		(n_ent) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) + \
		(n_arr) * sizeof(duk_tval) + \
		(n_hash) * sizeof(duk_uint32_t) \
	)
#define DUK_HOBJECT_P_SET_REALLOC_PTRS(p_base,set_e_k,set_e_pv,set_e_f,set_a,set_h,n_ent,n_arr,n_hash)  do { \
		(set_e_k) = (duk_hstring **) (void *) (p_base); \
		(set_e_pv) = (duk_propvalue *) (void *) ((set_e_k) + (n_ent)); \
		(set_e_f) = (duk_uint8_t *) (void *) ((set_e_pv) + (n_ent)); \
		(set_a) = (duk_tval *) (void *) ((set_e_f) + (n_ent)); \
		(set_h) = (duk_uint32_t *) (void *) ((set_a) + (n_arr)); \
	} while (0)
#elif defined(DUK_USE_HOBJECT_LAYOUT_2)
/* LAYOUT 2 */
#if (DUK_USE_ALIGN_BY == 4)
#define DUK_HOBJECT_E_FLAG_PADDING(e_sz) ((4 - (e_sz)) & 0x03)
#elif (DUK_USE_ALIGN_BY == 8)
#define DUK_HOBJECT_E_FLAG_PADDING(e_sz) ((8 - (e_sz)) & 0x07)
#elif (DUK_USE_ALIGN_BY == 1)
#define DUK_HOBJECT_E_FLAG_PADDING(e_sz) 0
#else
#error invalid DUK_USE_ALIGN_BY
#endif
#define DUK_HOBJECT_E_GET_KEY_BASE(heap,h) \
	((duk_hstring **) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * sizeof(duk_propvalue) \
	))
#define DUK_HOBJECT_E_GET_VALUE_BASE(heap,h) \
	((duk_propvalue *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) \
	))
#define DUK_HOBJECT_E_GET_FLAGS_BASE(heap,h) \
	((duk_uint8_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue)) \
	))
#define DUK_HOBJECT_A_GET_BASE(heap,h) \
	((duk_tval *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) + \
			DUK_HOBJECT_E_FLAG_PADDING(DUK_HOBJECT_GET_ESIZE((h))) \
	))
#define DUK_HOBJECT_H_GET_BASE(heap,h) \
	((duk_uint32_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) + \
			DUK_HOBJECT_E_FLAG_PADDING(DUK_HOBJECT_GET_ESIZE((h))) + \
			DUK_HOBJECT_GET_ASIZE((h)) * sizeof(duk_tval) \
	))
#define DUK_HOBJECT_P_COMPUTE_SIZE(n_ent,n_arr,n_hash) \
	( \
		(n_ent) * (sizeof(duk_hstring *) + sizeof(duk_propvalue) + sizeof(duk_uint8_t)) + \
		DUK_HOBJECT_E_FLAG_PADDING((n_ent)) + \
		(n_arr) * sizeof(duk_tval) + \
		(n_hash) * sizeof(duk_uint32_t) \
	)
#define DUK_HOBJECT_P_SET_REALLOC_PTRS(p_base,set_e_k,set_e_pv,set_e_f,set_a,set_h,n_ent,n_arr,n_hash)  do { \
		(set_e_pv) = (duk_propvalue *) (void *) (p_base); \
		(set_e_k) = (duk_hstring **) (void *) ((set_e_pv) + (n_ent)); \
		(set_e_f) = (duk_uint8_t *) (void *) ((set_e_k) + (n_ent)); \
		(set_a) = (duk_tval *) (void *) (((duk_uint8_t *) (set_e_f)) + \
		                                 sizeof(duk_uint8_t) * (n_ent) + \
		                                 DUK_HOBJECT_E_FLAG_PADDING((n_ent))); \
		(set_h) = (duk_uint32_t *) (void *) ((set_a) + (n_arr)); \
	} while (0)
#elif defined(DUK_USE_HOBJECT_LAYOUT_3)
/* LAYOUT 3 */
#define DUK_HOBJECT_E_GET_KEY_BASE(heap,h) \
	((duk_hstring **) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * sizeof(duk_propvalue) + \
			DUK_HOBJECT_GET_ASIZE((h)) * sizeof(duk_tval) \
	))
#define DUK_HOBJECT_E_GET_VALUE_BASE(heap,h) \
	((duk_propvalue *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) \
	))
#define DUK_HOBJECT_E_GET_FLAGS_BASE(heap,h) \
	((duk_uint8_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_propvalue) + sizeof(duk_hstring *)) + \
			DUK_HOBJECT_GET_ASIZE((h)) * sizeof(duk_tval) + \
			DUK_HOBJECT_GET_HSIZE((h)) * sizeof(duk_uint32_t) \
	))
#define DUK_HOBJECT_A_GET_BASE(heap,h) \
	((duk_tval *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * sizeof(duk_propvalue) \
	))
#define DUK_HOBJECT_H_GET_BASE(heap,h) \
	((duk_uint32_t *) (void *) ( \
		DUK_HOBJECT_GET_PROPS((heap), (h)) + \
			DUK_HOBJECT_GET_ESIZE((h)) * (sizeof(duk_propvalue) + sizeof(duk_hstring *)) + \
			DUK_HOBJECT_GET_ASIZE((h)) * sizeof(duk_tval) \
	))
#define DUK_HOBJECT_P_COMPUTE_SIZE(n_ent,n_arr,n_hash) \
	( \
		(n_ent) * (sizeof(duk_propvalue) + sizeof(duk_hstring *) + sizeof(duk_uint8_t)) + \
		(n_arr) * sizeof(duk_tval) + \
		(n_hash) * sizeof(duk_uint32_t) \
	)
#define DUK_HOBJECT_P_SET_REALLOC_PTRS(p_base,set_e_k,set_e_pv,set_e_f,set_a,set_h,n_ent,n_arr,n_hash)  do { \
		(set_e_pv) = (duk_propvalue *) (void *) (p_base); \
		(set_a) = (duk_tval *) (void *) ((set_e_pv) + (n_ent)); \
		(set_e_k) = (duk_hstring **) (void *) ((set_a) + (n_arr)); \
		(set_h) = (duk_uint32_t *) (void *) ((set_e_k) + (n_ent)); \
		(set_e_f) = (duk_uint8_t *) (void *) ((set_h) + (n_hash)); \
	} while (0)
#else
#error invalid hobject layout defines
#endif  /* hobject property layout */

#define DUK_HOBJECT_P_ALLOC_SIZE(h) \
	DUK_HOBJECT_P_COMPUTE_SIZE(DUK_HOBJECT_GET_ESIZE((h)), DUK_HOBJECT_GET_ASIZE((h)), DUK_HOBJECT_GET_HSIZE((h)))

#define DUK_HOBJECT_E_GET_KEY(heap,h,i)              (DUK_HOBJECT_E_GET_KEY_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_E_GET_KEY_PTR(heap,h,i)          (&DUK_HOBJECT_E_GET_KEY_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_E_GET_VALUE(heap,h,i)            (DUK_HOBJECT_E_GET_VALUE_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_E_GET_VALUE_PTR(heap,h,i)        (&DUK_HOBJECT_E_GET_VALUE_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_E_GET_VALUE_TVAL(heap,h,i)       (DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).v)
#define DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(heap,h,i)   (&DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).v)
#define DUK_HOBJECT_E_GET_VALUE_GETTER(heap,h,i)     (DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.get)
#define DUK_HOBJECT_E_GET_VALUE_GETTER_PTR(heap,h,i) (&DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.get)
#define DUK_HOBJECT_E_GET_VALUE_SETTER(heap,h,i)     (DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.set)
#define DUK_HOBJECT_E_GET_VALUE_SETTER_PTR(heap,h,i) (&DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.set)
#define DUK_HOBJECT_E_GET_FLAGS(heap,h,i)            (DUK_HOBJECT_E_GET_FLAGS_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_E_GET_FLAGS_PTR(heap,h,i)        (&DUK_HOBJECT_E_GET_FLAGS_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_A_GET_VALUE(heap,h,i)            (DUK_HOBJECT_A_GET_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_A_GET_VALUE_PTR(heap,h,i)        (&DUK_HOBJECT_A_GET_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_H_GET_INDEX(heap,h,i)            (DUK_HOBJECT_H_GET_BASE((heap), (h))[(i)])
#define DUK_HOBJECT_H_GET_INDEX_PTR(heap,h,i)        (&DUK_HOBJECT_H_GET_BASE((heap), (h))[(i)])

#define DUK_HOBJECT_E_SET_KEY(heap,h,i,k)  do { \
		DUK_HOBJECT_E_GET_KEY((heap), (h), (i)) = (k); \
	} while (0)
#define DUK_HOBJECT_E_SET_VALUE(heap,h,i,v)  do { \
		DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)) = (v); \
	} while (0)
#define DUK_HOBJECT_E_SET_VALUE_TVAL(heap,h,i,v)  do { \
		DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).v = (v); \
	} while (0)
#define DUK_HOBJECT_E_SET_VALUE_GETTER(heap,h,i,v)  do { \
		DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.get = (v); \
	} while (0)
#define DUK_HOBJECT_E_SET_VALUE_SETTER(heap,h,i,v)  do { \
		DUK_HOBJECT_E_GET_VALUE((heap), (h), (i)).a.set = (v); \
	} while (0)
#define DUK_HOBJECT_E_SET_FLAGS(heap,h,i,f)  do { \
		DUK_HOBJECT_E_GET_FLAGS((heap), (h), (i)) = (duk_uint8_t) (f); \
	} while (0)
#define DUK_HOBJECT_A_SET_VALUE(heap,h,i,v)  do { \
		DUK_HOBJECT_A_GET_VALUE((heap), (h), (i)) = (v); \
	} while (0)
#define DUK_HOBJECT_A_SET_VALUE_TVAL(heap,h,i,v) \
	DUK_HOBJECT_A_SET_VALUE((heap), (h), (i), (v))  /* alias for above */
#define DUK_HOBJECT_H_SET_INDEX(heap,h,i,v)  do { \
		DUK_HOBJECT_H_GET_INDEX((heap), (h), (i)) = (v); \
	} while (0)

#define DUK_HOBJECT_E_SET_FLAG_BITS(heap,h,i,mask)  do { \
		DUK_HOBJECT_E_GET_FLAGS_BASE((heap), (h))[(i)] |= (mask); \
	} while (0)

#define DUK_HOBJECT_E_CLEAR_FLAG_BITS(heap,h,i,mask)  do { \
		DUK_HOBJECT_E_GET_FLAGS_BASE((heap), (h))[(i)] &= ~(mask); \
	} while (0)

#define DUK_HOBJECT_E_SLOT_IS_WRITABLE(heap,h,i)     ((DUK_HOBJECT_E_GET_FLAGS((heap), (h), (i)) & DUK_PROPDESC_FLAG_WRITABLE) != 0)
#define DUK_HOBJECT_E_SLOT_IS_ENUMERABLE(heap,h,i)   ((DUK_HOBJECT_E_GET_FLAGS((heap), (h), (i)) & DUK_PROPDESC_FLAG_ENUMERABLE) != 0)
#define DUK_HOBJECT_E_SLOT_IS_CONFIGURABLE(heap,h,i) ((DUK_HOBJECT_E_GET_FLAGS((heap), (h), (i)) & DUK_PROPDESC_FLAG_CONFIGURABLE) != 0)
#define DUK_HOBJECT_E_SLOT_IS_ACCESSOR(heap,h,i)     ((DUK_HOBJECT_E_GET_FLAGS((heap), (h), (i)) & DUK_PROPDESC_FLAG_ACCESSOR) != 0)

#define DUK_HOBJECT_E_SLOT_SET_WRITABLE(heap,h,i)        DUK_HOBJECT_E_SET_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_WRITABLE)
#define DUK_HOBJECT_E_SLOT_SET_ENUMERABLE(heap,h,i)      DUK_HOBJECT_E_SET_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_ENUMERABLE)
#define DUK_HOBJECT_E_SLOT_SET_CONFIGURABLE(heap,h,i)    DUK_HOBJECT_E_SET_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_CONFIGURABLE)
#define DUK_HOBJECT_E_SLOT_SET_ACCESSOR(heap,h,i)        DUK_HOBJECT_E_SET_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_ACCESSOR)

#define DUK_HOBJECT_E_SLOT_CLEAR_WRITABLE(heap,h,i)      DUK_HOBJECT_E_CLEAR_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_WRITABLE)
#define DUK_HOBJECT_E_SLOT_CLEAR_ENUMERABLE(heap,h,i)    DUK_HOBJECT_E_CLEAR_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_ENUMERABLE)
#define DUK_HOBJECT_E_SLOT_CLEAR_CONFIGURABLE(heap,h,i)  DUK_HOBJECT_E_CLEAR_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_CONFIGURABLE)
#define DUK_HOBJECT_E_SLOT_CLEAR_ACCESSOR(heap,h,i)      DUK_HOBJECT_E_CLEAR_FLAG_BITS((heap), (h), (i),DUK_PROPDESC_FLAG_ACCESSOR)

#define DUK_PROPDESC_IS_WRITABLE(p)             (((p)->flags & DUK_PROPDESC_FLAG_WRITABLE) != 0)
#define DUK_PROPDESC_IS_ENUMERABLE(p)           (((p)->flags & DUK_PROPDESC_FLAG_ENUMERABLE) != 0)
#define DUK_PROPDESC_IS_CONFIGURABLE(p)         (((p)->flags & DUK_PROPDESC_FLAG_CONFIGURABLE) != 0)
#define DUK_PROPDESC_IS_ACCESSOR(p)             (((p)->flags & DUK_PROPDESC_FLAG_ACCESSOR) != 0)

#define DUK_HOBJECT_HASHIDX_UNUSED              0xffffffffUL
#define DUK_HOBJECT_HASHIDX_DELETED             0xfffffffeUL

/*
 *  Macros for accessing size fields
 */

#if defined(DUK_USE_OBJSIZES16)
#define DUK_HOBJECT_GET_ESIZE(h) ((h)->e_size16)
#define DUK_HOBJECT_SET_ESIZE(h,v) do { (h)->e_size16 = (v); } while (0)
#define DUK_HOBJECT_GET_ENEXT(h) ((h)->e_next16)
#define DUK_HOBJECT_SET_ENEXT(h,v) do { (h)->e_next16 = (v); } while (0)
#define DUK_HOBJECT_POSTINC_ENEXT(h) ((h)->e_next16++)
#define DUK_HOBJECT_GET_ASIZE(h) ((h)->a_size16)
#define DUK_HOBJECT_SET_ASIZE(h,v) do { (h)->a_size16 = (v); } while (0)
#if defined(DUK_USE_HOBJECT_HASH_PART)
#define DUK_HOBJECT_GET_HSIZE(h) ((h)->h_size16)
#define DUK_HOBJECT_SET_HSIZE(h,v) do { (h)->h_size16 = (v); } while (0)
#else
#define DUK_HOBJECT_GET_HSIZE(h) 0
#define DUK_HOBJECT_SET_HSIZE(h,v) do { DUK_ASSERT((v) == 0); } while (0)
#endif
#else
#define DUK_HOBJECT_GET_ESIZE(h) ((h)->e_size)
#define DUK_HOBJECT_SET_ESIZE(h,v) do { (h)->e_size = (v); } while (0)
#define DUK_HOBJECT_GET_ENEXT(h) ((h)->e_next)
#define DUK_HOBJECT_SET_ENEXT(h,v) do { (h)->e_next = (v); } while (0)
#define DUK_HOBJECT_POSTINC_ENEXT(h) ((h)->e_next++)
#define DUK_HOBJECT_GET_ASIZE(h) ((h)->a_size)
#define DUK_HOBJECT_SET_ASIZE(h,v) do { (h)->a_size = (v); } while (0)
#if defined(DUK_USE_HOBJECT_HASH_PART)
#define DUK_HOBJECT_GET_HSIZE(h) ((h)->h_size)
#define DUK_HOBJECT_SET_HSIZE(h,v) do { (h)->h_size = (v); } while (0)
#else
#define DUK_HOBJECT_GET_HSIZE(h) 0
#define DUK_HOBJECT_SET_HSIZE(h,v) do { DUK_ASSERT((v) == 0); } while (0)
#endif
#endif

/*
 *  Misc
 */

/* Maximum prototype traversal depth.  Sanity limit which handles e.g.
 * prototype loops (even complex ones like 1->2->3->4->2->3->4->2->3->4).
 */
#define DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY      10000L

/*
 *  ECMAScript [[Class]]
 */

/* range check not necessary because all 4-bit values are mapped */
#define DUK_HOBJECT_CLASS_NUMBER_TO_STRIDX(n)  duk_class_number_to_stridx[(n)]

#define DUK_HOBJECT_GET_CLASS_STRING(heap,h)          \
	DUK_HEAP_GET_STRING( \
		(heap), \
		DUK_HOBJECT_CLASS_NUMBER_TO_STRIDX(DUK_HOBJECT_GET_CLASS_NUMBER((h))) \
	)

/*
 *  Macros for property handling
 */

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HOBJECT_GET_PROTOTYPE(heap,h) \
	((duk_hobject *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->prototype16))
#define DUK_HOBJECT_SET_PROTOTYPE(heap,h,x) do { \
		(h)->prototype16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (x)); \
	} while (0)
#else
#define DUK_HOBJECT_GET_PROTOTYPE(heap,h) \
	((h)->prototype)
#define DUK_HOBJECT_SET_PROTOTYPE(heap,h,x) do { \
		(h)->prototype = (x); \
	} while (0)
#endif

/* Set prototype, DECREF earlier value, INCREF new value (tolerating NULLs). */
#define DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr,h,p)       duk_hobject_set_prototype_updref((thr), (h), (p))

/* Set initial prototype, assume NULL previous prototype, INCREF new value,
 * tolerate NULL.
 */
#define DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr,h,proto) do { \
		duk_hthread *duk__thr = (thr); \
		duk_hobject *duk__obj = (h); \
		duk_hobject *duk__proto = (proto); \
		DUK_UNREF(duk__thr); \
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(duk__thr->heap, duk__obj) == NULL); \
		DUK_HOBJECT_SET_PROTOTYPE(duk__thr->heap, duk__obj, duk__proto); \
		DUK_HOBJECT_INCREF_ALLOWNULL(duk__thr, duk__proto); \
	} while (0)

/*
 *  Finalizer check
 */

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HOBJECT_HAS_FINALIZER_FAST(heap,h) duk_hobject_has_finalizer_fast_raw((heap), (h))
#else
#define DUK_HOBJECT_HAS_FINALIZER_FAST(heap,h) duk_hobject_has_finalizer_fast_raw((h))
#endif

/*
 *  Resizing and hash behavior
 */

/* Sanity limit on max number of properties (allocated, not necessarily used).
 * This is somewhat arbitrary, but if we're close to 2**32 properties some
 * algorithms will fail (e.g. hash size selection, next prime selection).
 * Also, we use negative array/entry table indices to indicate 'not found',
 * so anything above 0x80000000 will cause trouble now.
 */
#if defined(DUK_USE_OBJSIZES16)
#define DUK_HOBJECT_MAX_PROPERTIES       0x0000ffffUL
#else
#define DUK_HOBJECT_MAX_PROPERTIES       0x3fffffffUL   /* 2**30-1 ~= 1G properties */
#endif

/* internal align target for props allocation, must be 2*n for some n */
#if (DUK_USE_ALIGN_BY == 4)
#define DUK_HOBJECT_ALIGN_TARGET         4
#elif (DUK_USE_ALIGN_BY == 8)
#define DUK_HOBJECT_ALIGN_TARGET         8
#elif (DUK_USE_ALIGN_BY == 1)
#define DUK_HOBJECT_ALIGN_TARGET         1
#else
#error invalid DUK_USE_ALIGN_BY
#endif

/*
 *  PC-to-line constants
 */

#define DUK_PC2LINE_SKIP    64

/* maximum length for a SKIP-1 diffstream: 35 bits per entry, rounded up to bytes */
#define DUK_PC2LINE_MAX_DIFF_LENGTH    (((DUK_PC2LINE_SKIP - 1) * 35 + 7) / 8)

/*
 *  Struct defs
 */

struct duk_propaccessor {
	duk_hobject *get;
	duk_hobject *set;
};

union duk_propvalue {
	/* The get/set pointers could be 16-bit pointer compressed but it
	 * would make no difference on 32-bit platforms because duk_tval is
	 * 8 bytes or more anyway.
	 */
	duk_tval v;
	duk_propaccessor a;
};

struct duk_propdesc {
	/* read-only values 'lifted' for ease of use */
	duk_small_uint_t flags;
	duk_hobject *get;
	duk_hobject *set;

	/* for updating (all are set to < 0 for virtual properties) */
	duk_int_t e_idx;  /* prop index in 'entry part', < 0 if not there */
	duk_int_t h_idx;  /* prop index in 'hash part', < 0 if not there */
	duk_int_t a_idx;  /* prop index in 'array part', < 0 if not there */
};

struct duk_hobject {
	duk_heaphdr hdr;

	/*
	 *  'props' contains {key,value,flags} entries, optional array entries, and
	 *  an optional hash lookup table for non-array entries in a single 'sliced'
	 *  allocation.  There are several layout options, which differ slightly in
	 *  generated code size/speed and alignment/padding; duk_features.h selects
	 *  the layout used.
	 *
	 *  Layout 1 (DUK_USE_HOBJECT_LAYOUT_1):
	 *
	 *    e_size * sizeof(duk_hstring *)         bytes of   entry keys (e_next gc reachable)
	 *    e_size * sizeof(duk_propvalue)         bytes of   entry values (e_next gc reachable)
	 *    e_size * sizeof(duk_uint8_t)           bytes of   entry flags (e_next gc reachable)
	 *    a_size * sizeof(duk_tval)              bytes of   (opt) array values (plain only) (all gc reachable)
	 *    h_size * sizeof(duk_uint32_t)          bytes of   (opt) hash indexes to entries (e_size),
	 *                                                      0xffffffffUL = unused, 0xfffffffeUL = deleted
	 *
	 *  Layout 2 (DUK_USE_HOBJECT_LAYOUT_2):
	 *
	 *    e_size * sizeof(duk_propvalue)         bytes of   entry values (e_next gc reachable)
	 *    e_size * sizeof(duk_hstring *)         bytes of   entry keys (e_next gc reachable)
	 *    e_size * sizeof(duk_uint8_t) + pad     bytes of   entry flags (e_next gc reachable)
	 *    a_size * sizeof(duk_tval)              bytes of   (opt) array values (plain only) (all gc reachable)
	 *    h_size * sizeof(duk_uint32_t)          bytes of   (opt) hash indexes to entries (e_size),
	 *                                                      0xffffffffUL = unused, 0xfffffffeUL = deleted
	 *
	 *  Layout 3 (DUK_USE_HOBJECT_LAYOUT_3):
	 *
	 *    e_size * sizeof(duk_propvalue)         bytes of   entry values (e_next gc reachable)
	 *    a_size * sizeof(duk_tval)              bytes of   (opt) array values (plain only) (all gc reachable)
	 *    e_size * sizeof(duk_hstring *)         bytes of   entry keys (e_next gc reachable)
	 *    h_size * sizeof(duk_uint32_t)          bytes of   (opt) hash indexes to entries (e_size),
	 *                                                      0xffffffffUL = unused, 0xfffffffeUL = deleted
	 *    e_size * sizeof(duk_uint8_t)           bytes of   entry flags (e_next gc reachable)
	 *
	 *  In layout 1, the 'e_next' count is rounded to 4 or 8 on platforms
	 *  requiring 4 or 8 byte alignment.  This ensures proper alignment
	 *  for the entries, at the cost of memory footprint.  However, it's
	 *  probably preferable to use another layout on such platforms instead.
	 *
	 *  In layout 2, the key and value parts are swapped to avoid padding
	 *  the key array on platforms requiring alignment by 8.  The flags part
	 *  is padded to get alignment for array entries.  The 'e_next' count does
	 *  not need to be rounded as in layout 1.
	 *
	 *  In layout 3, entry values and array values are always aligned properly,
	 *  and assuming pointers are at most 8 bytes, so are the entry keys.  Hash
	 *  indices will be properly aligned (assuming pointers are at least 4 bytes).
	 *  Finally, flags don't need additional alignment.  This layout provides
	 *  compact allocations without padding (even on platforms with alignment
	 *  requirements) at the cost of a bit slower lookups.
	 *
	 *  Objects with few keys don't have a hash index; keys are looked up linearly,
	 *  which is cache efficient because the keys are consecutive.  Larger objects
	 *  have a hash index part which contains integer indexes to the entries part.
	 *
	 *  A single allocation reduces memory allocation overhead but requires more
	 *  work when any part needs to be resized.  A sliced allocation for entries
	 *  makes linear key matching faster on most platforms (more locality) and
	 *  skimps on flags size (which would be followed by 3 bytes of padding in
	 *  most architectures if entries were placed in a struct).
	 *
	 *  'props' also contains internal properties distinguished with a non-BMP
	 *  prefix.  Often used properties should be placed early in 'props' whenever
	 *  possible to make accessing them as fast a possible.
	 */

#if defined(DUK_USE_HEAPPTR16)
	/* Located in duk_heaphdr h_extra16.  Subclasses of duk_hobject (like
	 * duk_hcompfunc) are not free to use h_extra16 for this reason.
	 */
#else
	duk_uint8_t *props;
#endif

	/* prototype: the only internal property lifted outside 'e' as it is so central */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t prototype16;
#else
	duk_hobject *prototype;
#endif

#if defined(DUK_USE_OBJSIZES16)
	duk_uint16_t e_size16;
	duk_uint16_t e_next16;
	duk_uint16_t a_size16;
#if defined(DUK_USE_HOBJECT_HASH_PART)
	duk_uint16_t h_size16;
#endif
#else
	duk_uint32_t e_size;  /* entry part size */
	duk_uint32_t e_next;  /* index for next new key ([0,e_next[ are gc reachable) */
	duk_uint32_t a_size;  /* array part size (entirely gc reachable) */
#if defined(DUK_USE_HOBJECT_HASH_PART)
	duk_uint32_t h_size;  /* hash part size or 0 if unused */
#endif
#endif
};

/*
 *  Exposed data
 */

#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL duk_uint8_t duk_class_number_to_stridx[32];
#endif  /* !DUK_SINGLE_FILE */

/*
 *  Prototypes
 */

/* alloc and init */
DUK_INTERNAL_DECL duk_hobject *duk_hobject_alloc_unchecked(duk_heap *heap, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hobject *duk_hobject_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_harray *duk_harray_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hcompfunc *duk_hcompfunc_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hnatfunc *duk_hnatfunc_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hboundfunc *duk_hboundfunc_alloc(duk_heap *heap, duk_uint_t hobject_flags);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL_DECL duk_hbufobj *duk_hbufobj_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
#endif
DUK_INTERNAL_DECL duk_hthread *duk_hthread_alloc_unchecked(duk_heap *heap, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hthread *duk_hthread_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hdecenv *duk_hdecenv_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hobjenv *duk_hobjenv_alloc(duk_hthread *thr, duk_uint_t hobject_flags);
DUK_INTERNAL_DECL duk_hproxy *duk_hproxy_alloc(duk_hthread *thr, duk_uint_t hobject_flags);

/* resize */
DUK_INTERNAL_DECL void duk_hobject_realloc_props(duk_hthread *thr,
                                                 duk_hobject *obj,
                                                 duk_uint32_t new_e_size,
                                                 duk_uint32_t new_a_size,
                                                 duk_uint32_t new_h_size,
                                                 duk_bool_t abandon_array);
DUK_INTERNAL_DECL void duk_hobject_resize_entrypart(duk_hthread *thr,
                                                    duk_hobject *obj,
                                                    duk_uint32_t new_e_size);
#if 0  /*unused*/
DUK_INTERNAL_DECL void duk_hobject_resize_arraypart(duk_hthread *thr,
                                                    duk_hobject *obj,
                                                    duk_uint32_t new_a_size);
#endif

/* low-level property functions */
DUK_INTERNAL_DECL duk_bool_t duk_hobject_find_entry(duk_heap *heap, duk_hobject *obj, duk_hstring *key, duk_int_t *e_idx, duk_int_t *h_idx);
DUK_INTERNAL_DECL duk_tval *duk_hobject_find_entry_tval_ptr(duk_heap *heap, duk_hobject *obj, duk_hstring *key);
DUK_INTERNAL_DECL duk_tval *duk_hobject_find_entry_tval_ptr_stridx(duk_heap *heap, duk_hobject *obj, duk_small_uint_t stridx);
DUK_INTERNAL_DECL duk_tval *duk_hobject_find_entry_tval_ptr_and_attrs(duk_heap *heap, duk_hobject *obj, duk_hstring *key, duk_uint_t *out_attrs);
DUK_INTERNAL_DECL duk_tval *duk_hobject_find_array_entry_tval_ptr(duk_heap *heap, duk_hobject *obj, duk_uarridx_t i);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_get_own_propdesc(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *out_desc, duk_small_uint_t flags);

/* core property functions */
DUK_INTERNAL_DECL duk_bool_t duk_hobject_getprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_putprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key, duk_tval *tv_val, duk_bool_t throw_flag);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_delprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key, duk_bool_t throw_flag);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_hasprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key);

/* internal property functions */
#define DUK_DELPROP_FLAG_THROW  (1U << 0)
#define DUK_DELPROP_FLAG_FORCE  (1U << 1)
DUK_INTERNAL_DECL duk_bool_t duk_hobject_delprop_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_hasprop_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key);
DUK_INTERNAL_DECL void duk_hobject_define_property_internal(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_small_uint_t flags);
DUK_INTERNAL_DECL void duk_hobject_define_property_internal_arridx(duk_hthread *thr, duk_hobject *obj, duk_uarridx_t arr_idx, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_size_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj);
#if defined(DUK_USE_HEAPPTR16)
DUK_INTERNAL_DECL duk_bool_t duk_hobject_has_finalizer_fast_raw(duk_heap *heap, duk_hobject *obj);
#else
DUK_INTERNAL_DECL duk_bool_t duk_hobject_has_finalizer_fast_raw(duk_hobject *obj);
#endif

/* helpers for defineProperty() and defineProperties() */
DUK_INTERNAL_DECL void duk_hobject_prepare_property_descriptor(duk_hthread *thr,
                                                               duk_idx_t idx_in,
                                                               duk_uint_t *out_defprop_flags,
                                                               duk_idx_t *out_idx_value,
                                                               duk_hobject **out_getter,
                                                               duk_hobject **out_setter);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_define_property_helper(duk_hthread *thr,
                                                                duk_uint_t defprop_flags,
                                                                duk_hobject *obj,
                                                                duk_hstring *key,
                                                                duk_idx_t idx_value,
                                                                duk_hobject *get,
                                                                duk_hobject *set,
                                                                duk_bool_t throw_flag);

/* Object built-in methods */
DUK_INTERNAL_DECL void duk_hobject_object_get_own_property_descriptor(duk_hthread *thr, duk_idx_t obj_idx);
DUK_INTERNAL_DECL void duk_hobject_object_seal_freeze_helper(duk_hthread *thr, duk_hobject *obj, duk_bool_t is_freeze);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_object_is_sealed_frozen_helper(duk_hthread *thr, duk_hobject *obj, duk_bool_t is_frozen);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_object_ownprop_helper(duk_hthread *thr, duk_small_uint_t required_desc_flags);

/* internal properties */
DUK_INTERNAL_DECL duk_tval *duk_hobject_get_internal_value_tval_ptr(duk_heap *heap, duk_hobject *obj);
DUK_INTERNAL_DECL duk_hstring *duk_hobject_get_internal_value_string(duk_heap *heap, duk_hobject *obj);
DUK_INTERNAL_DECL duk_harray *duk_hobject_get_formals(duk_hthread *thr, duk_hobject *obj);
DUK_INTERNAL_DECL duk_hobject *duk_hobject_get_varmap(duk_hthread *thr, duk_hobject *obj);

/* hobject management functions */
DUK_INTERNAL_DECL void duk_hobject_compact_props(duk_hthread *thr, duk_hobject *obj);

/* ES2015 proxy */
#if defined(DUK_USE_ES6_PROXY)
DUK_INTERNAL_DECL duk_bool_t duk_hobject_proxy_check(duk_hobject *obj, duk_hobject **out_target, duk_hobject **out_handler);
DUK_INTERNAL_DECL duk_hobject *duk_hobject_resolve_proxy_target(duk_hobject *obj);
#endif

/* enumeration */
DUK_INTERNAL_DECL void duk_hobject_enumerator_create(duk_hthread *thr, duk_small_uint_t enum_flags);
DUK_INTERNAL_DECL duk_ret_t duk_hobject_get_enumerated_keys(duk_hthread *thr, duk_small_uint_t enum_flags);
DUK_INTERNAL_DECL duk_bool_t duk_hobject_enumerator_next(duk_hthread *thr, duk_bool_t get_value);

/* macros */
DUK_INTERNAL_DECL void duk_hobject_set_prototype_updref(duk_hthread *thr, duk_hobject *h, duk_hobject *p);

/* pc2line */
#if defined(DUK_USE_PC2LINE)
DUK_INTERNAL_DECL void duk_hobject_pc2line_pack(duk_hthread *thr, duk_compiler_instr *instrs, duk_uint_fast32_t length);
DUK_INTERNAL_DECL duk_uint_fast32_t duk_hobject_pc2line_query(duk_hthread *thr, duk_idx_t idx_func, duk_uint_fast32_t pc);
#endif

/* misc */
DUK_INTERNAL_DECL duk_bool_t duk_hobject_prototype_chain_contains(duk_hthread *thr, duk_hobject *h, duk_hobject *p, duk_bool_t ignore_loop);

#if !defined(DUK_USE_OBJECT_BUILTIN)
/* These declarations are needed when related built-in is disabled and
 * genbuiltins.py won't automatically emit the declerations.
 */
DUK_INTERNAL_DECL duk_ret_t duk_bi_object_prototype_to_string(duk_hthread *thr);
DUK_INTERNAL_DECL duk_ret_t duk_bi_function_prototype(duk_hthread *thr);
#endif

#endif  /* DUK_HOBJECT_H_INCLUDED */
/* #include duk_hcompfunc.h */
/*
 *  Heap compiled function (ECMAScript function) representation.
 *
 *  There is a single data buffer containing the ECMAScript function's
 *  bytecode, constants, and inner functions.
 */

#if !defined(DUK_HCOMPFUNC_H_INCLUDED)
#define DUK_HCOMPFUNC_H_INCLUDED

/*
 *  Field accessor macros
 */

/* XXX: casts could be improved, especially for GET/SET DATA */

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HCOMPFUNC_GET_DATA(heap,h) \
	((duk_hbuffer_fixed *) (void *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->data16))
#define DUK_HCOMPFUNC_SET_DATA(heap,h,v) do { \
		(h)->data16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#define DUK_HCOMPFUNC_GET_FUNCS(heap,h)  \
	((duk_hobject **) (void *) (DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->funcs16)))
#define DUK_HCOMPFUNC_SET_FUNCS(heap,h,v)  do { \
		(h)->funcs16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#define DUK_HCOMPFUNC_GET_BYTECODE(heap,h)  \
	((duk_instr_t *) (void *) (DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->bytecode16)))
#define DUK_HCOMPFUNC_SET_BYTECODE(heap,h,v)  do { \
		(h)->bytecode16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#define DUK_HCOMPFUNC_GET_LEXENV(heap,h)  \
	((duk_hobject *) (void *) (DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->lex_env16)))
#define DUK_HCOMPFUNC_SET_LEXENV(heap,h,v)  do { \
		(h)->lex_env16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#define DUK_HCOMPFUNC_GET_VARENV(heap,h)  \
	((duk_hobject *) (void *) (DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (h)->var_env16)))
#define DUK_HCOMPFUNC_SET_VARENV(heap,h,v)  do { \
		(h)->var_env16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#else
#define DUK_HCOMPFUNC_GET_DATA(heap,h)  ((duk_hbuffer_fixed *) (void *) (h)->data)
#define DUK_HCOMPFUNC_SET_DATA(heap,h,v) do { \
		(h)->data = (duk_hbuffer *) (v); \
	} while (0)
#define DUK_HCOMPFUNC_GET_FUNCS(heap,h)  ((h)->funcs)
#define DUK_HCOMPFUNC_SET_FUNCS(heap,h,v)  do { \
		(h)->funcs = (v); \
	} while (0)
#define DUK_HCOMPFUNC_GET_BYTECODE(heap,h)  ((h)->bytecode)
#define DUK_HCOMPFUNC_SET_BYTECODE(heap,h,v)  do { \
		(h)->bytecode = (v); \
	} while (0)
#define DUK_HCOMPFUNC_GET_LEXENV(heap,h)  ((h)->lex_env)
#define DUK_HCOMPFUNC_SET_LEXENV(heap,h,v)  do { \
		(h)->lex_env = (v); \
	} while (0)
#define DUK_HCOMPFUNC_GET_VARENV(heap,h)  ((h)->var_env)
#define DUK_HCOMPFUNC_SET_VARENV(heap,h,v)  do { \
		(h)->var_env = (v); \
	} while (0)
#endif

/*
 *  Accessor macros for function specific data areas
 */

/* Note: assumes 'data' is always a fixed buffer */
#define DUK_HCOMPFUNC_GET_BUFFER_BASE(heap,h)  \
	DUK_HBUFFER_FIXED_GET_DATA_PTR((heap), DUK_HCOMPFUNC_GET_DATA((heap), (h)))

#define DUK_HCOMPFUNC_GET_CONSTS_BASE(heap,h)  \
	((duk_tval *) (void *) DUK_HCOMPFUNC_GET_BUFFER_BASE((heap), (h)))

#define DUK_HCOMPFUNC_GET_FUNCS_BASE(heap,h)  \
	DUK_HCOMPFUNC_GET_FUNCS((heap), (h))

#define DUK_HCOMPFUNC_GET_CODE_BASE(heap,h)  \
	DUK_HCOMPFUNC_GET_BYTECODE((heap), (h))

#define DUK_HCOMPFUNC_GET_CONSTS_END(heap,h)  \
	((duk_tval *) (void *) DUK_HCOMPFUNC_GET_FUNCS((heap), (h)))

#define DUK_HCOMPFUNC_GET_FUNCS_END(heap,h)  \
	((duk_hobject **) (void *) DUK_HCOMPFUNC_GET_BYTECODE((heap), (h)))

/* XXX: double evaluation of DUK_HCOMPFUNC_GET_DATA() */
#define DUK_HCOMPFUNC_GET_CODE_END(heap,h)  \
	((duk_instr_t *) (void *) (DUK_HBUFFER_FIXED_GET_DATA_PTR((heap), DUK_HCOMPFUNC_GET_DATA((heap), (h))) + \
	                DUK_HBUFFER_GET_SIZE((duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA((heap), h))))

#define DUK_HCOMPFUNC_GET_CONSTS_SIZE(heap,h)  \
	( \
	 (duk_size_t) \
	 ( \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_CONSTS_END((heap), (h))) - \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_CONSTS_BASE((heap), (h))) \
	 ) \
	)

#define DUK_HCOMPFUNC_GET_FUNCS_SIZE(heap,h)  \
	( \
	 (duk_size_t) \
	 ( \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_FUNCS_END((heap), (h))) - \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_FUNCS_BASE((heap), (h))) \
	 ) \
	)

#define DUK_HCOMPFUNC_GET_CODE_SIZE(heap,h)  \
	( \
	 (duk_size_t) \
	 ( \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_CODE_END((heap),(h))) - \
	   ((const duk_uint8_t *) DUK_HCOMPFUNC_GET_CODE_BASE((heap),(h))) \
	 ) \
	)

#define DUK_HCOMPFUNC_GET_CONSTS_COUNT(heap,h)  \
	((duk_size_t) (DUK_HCOMPFUNC_GET_CONSTS_SIZE((heap), (h)) / sizeof(duk_tval)))

#define DUK_HCOMPFUNC_GET_FUNCS_COUNT(heap,h)  \
	((duk_size_t) (DUK_HCOMPFUNC_GET_FUNCS_SIZE((heap), (h)) / sizeof(duk_hobject *)))

#define DUK_HCOMPFUNC_GET_CODE_COUNT(heap,h)  \
	((duk_size_t) (DUK_HCOMPFUNC_GET_CODE_SIZE((heap), (h)) / sizeof(duk_instr_t)))

/*
 *  Validity assert
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hcompfunc_assert_valid(duk_hcompfunc *h);
#define DUK_HCOMPFUNC_ASSERT_VALID(h)  do { duk_hcompfunc_assert_valid((h)); } while (0)
#else
#define DUK_HCOMPFUNC_ASSERT_VALID(h)  do {} while (0)
#endif

/*
 *  Main struct
 */

struct duk_hcompfunc {
	/* shared object part */
	duk_hobject obj;

	/*
	 *  Pointers to function data area for faster access.  Function
	 *  data is a buffer shared between all closures of the same
	 *  "template" function.  The data buffer is always fixed (non-
	 *  dynamic, hence stable), with a layout as follows:
	 *
	 *    constants (duk_tval)
	 *    inner functions (duk_hobject *)
	 *    bytecode (duk_instr_t)
	 *
	 *  Note: bytecode end address can be computed from 'data' buffer
	 *  size.  It is not strictly necessary functionally, assuming
	 *  bytecode never jumps outside its allocated area.  However,
	 *  it's a safety/robustness feature for avoiding the chance of
	 *  executing random data as bytecode due to a compiler error.
	 *
	 *  Note: values in the data buffer must be incref'd (they will
	 *  be decref'd on release) for every compiledfunction referring
	 *  to the 'data' element.
	 */

	/* Data area, fixed allocation, stable data ptrs. */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t data16;
#else
	duk_hbuffer *data;
#endif

	/* No need for constants pointer (= same as data).
	 *
	 * When using 16-bit packing alignment to 4 is nice.  'funcs' will be
	 * 4-byte aligned because 'constants' are duk_tvals.  For now the
	 * inner function pointers are not compressed, so that 'bytecode' will
	 * also be 4-byte aligned.
	 */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t funcs16;
	duk_uint16_t bytecode16;
#else
	duk_hobject **funcs;
	duk_instr_t *bytecode;
#endif

	/* Lexenv: lexical environment of closure, NULL for templates.
	 * Varenv: variable environment of closure, NULL for templates.
	 */
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t lex_env16;
	duk_uint16_t var_env16;
#else
	duk_hobject *lex_env;
	duk_hobject *var_env;
#endif

	/*
	 *  'nregs' registers are allocated on function entry, at most 'nargs'
	 *  are initialized to arguments, and the rest to undefined.  Arguments
	 *  above 'nregs' are not mapped to registers.  All registers in the
	 *  active stack range must be initialized because they are GC reachable.
	 *  'nargs' is needed so that if the function is given more than 'nargs'
	 *  arguments, the additional arguments do not 'clobber' registers
	 *  beyond 'nregs' which must be consistently initialized to undefined.
	 *
	 *  Usually there is no need to know which registers are mapped to
	 *  local variables.  Registers may be allocated to variable in any
	 *  way (even including gaps).  However, a register-variable mapping
	 *  must be the same for the duration of the function execution and
	 *  the register cannot be used for anything else.
	 *
	 *  When looking up variables by name, the '_Varmap' map is used.
	 *  When an activation closes, registers mapped to arguments are
	 *  copied into the environment record based on the same map.  The
	 *  reverse map (from register to variable) is not currently needed
	 *  at run time, except for debugging, so it is not maintained.
	 */

	duk_uint16_t nregs;                /* regs to allocate */
	duk_uint16_t nargs;                /* number of arguments allocated to regs */

	/*
	 *  Additional control information is placed into the object itself
	 *  as internal properties to avoid unnecessary fields for the
	 *  majority of functions.  The compiler tries to omit internal
	 *  control fields when possible.
	 *
	 *  Function templates:
	 *
	 *    {
	 *      name: "func",    // declaration, named function expressions
	 *      fileName: <debug info for creating nice errors>
	 *      _Varmap: { "arg1": 0, "arg2": 1, "varname": 2 },
	 *      _Formals: [ "arg1", "arg2" ],
	 *      _Source: "function func(arg1, arg2) { ... }",
	 *      _Pc2line: <debug info for pc-to-line mapping>,
	 *    }
	 *
	 *  Function instances:
	 *
	 *    {
	 *      length: 2,
	 *      prototype: { constructor: <func> },
	 *      caller: <thrower>,
	 *      arguments: <thrower>,
	 *      name: "func",    // declaration, named function expressions
	 *      fileName: <debug info for creating nice errors>
	 *      _Varmap: { "arg1": 0, "arg2": 1, "varname": 2 },
	 *      _Formals: [ "arg1", "arg2" ],
	 *      _Source: "function func(arg1, arg2) { ... }",
	 *      _Pc2line: <debug info for pc-to-line mapping>,
	 *    }
	 *
	 *  More detailed description of these properties can be found
	 *  in the documentation.
	 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	/* Line number range for function.  Needed during debugging to
	 * determine active breakpoints.
	 */
	duk_uint32_t start_line;
	duk_uint32_t end_line;
#endif
};

#endif  /* DUK_HCOMPFUNC_H_INCLUDED */
/* #include duk_hnatfunc.h */
/*
 *  Heap native function representation.
 */

#if !defined(DUK_HNATFUNC_H_INCLUDED)
#define DUK_HNATFUNC_H_INCLUDED

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hnatfunc_assert_valid(duk_hnatfunc *h);
#define DUK_HNATFUNC_ASSERT_VALID(h)  do { duk_hnatfunc_assert_valid((h)); } while (0)
#else
#define DUK_HNATFUNC_ASSERT_VALID(h)  do {} while (0)
#endif

#define DUK_HNATFUNC_NARGS_VARARGS  ((duk_int16_t) -1)
#define DUK_HNATFUNC_NARGS_MAX      ((duk_int16_t) 0x7fff)

struct duk_hnatfunc {
	/* shared object part */
	duk_hobject obj;

	duk_c_function func;
	duk_int16_t nargs;
	duk_int16_t magic;

	/* The 'magic' field allows an opaque 16-bit field to be accessed by the
	 * Duktape/C function.  This allows, for instance, the same native function
	 * to be used for a set of very similar functions, with the 'magic' field
	 * providing the necessary non-argument flags / values to guide the behavior
	 * of the native function.  The value is signed on purpose: it is easier to
	 * convert a signed value to unsigned (simply AND with 0xffff) than vice
	 * versa.
	 *
	 * Note: cannot place nargs/magic into the heaphdr flags, because
	 * duk_hobject takes almost all flags already.
	 */
};

#endif  /* DUK_HNATFUNC_H_INCLUDED */
/* #include duk_hboundfunc.h */
/*
 *  Bound function representation.
 */

#if !defined(DUK_HBOUNDFUNC_H_INCLUDED)
#define DUK_HBOUNDFUNC_H_INCLUDED

/* Artificial limit for args length.  Ensures arithmetic won't overflow
 * 32 bits when combining bound functions.
 */
#define DUK_HBOUNDFUNC_MAX_ARGS 0x20000000UL

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hboundfunc_assert_valid(duk_hboundfunc *h);
#define DUK_HBOUNDFUNC_ASSERT_VALID(h)  do { duk_hboundfunc_assert_valid((h)); } while (0)
#else
#define DUK_HBOUNDFUNC_ASSERT_VALID(h)  do {} while (0)
#endif

struct duk_hboundfunc {
	/* Shared object part. */
	duk_hobject obj;

	/* Final target function, stored as duk_tval so that lightfunc can be
	 * represented too.
	 */
	duk_tval target;

	/* This binding. */
	duk_tval this_binding;

	/* Arguments to prepend. */
	duk_tval *args;  /* Separate allocation. */
	duk_idx_t nargs;
};

#endif  /* DUK_HBOUNDFUNC_H_INCLUDED */
/* #include duk_hbufobj.h */
/*
 *  Heap Buffer object representation.  Used for all Buffer variants.
 */

#if !defined(DUK_HBUFOBJ_H_INCLUDED)
#define DUK_HBUFOBJ_H_INCLUDED

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)

/* All element accessors are host endian now (driven by TypedArray spec). */
#define DUK_HBUFOBJ_ELEM_UINT8           0
#define DUK_HBUFOBJ_ELEM_UINT8CLAMPED    1
#define DUK_HBUFOBJ_ELEM_INT8            2
#define DUK_HBUFOBJ_ELEM_UINT16          3
#define DUK_HBUFOBJ_ELEM_INT16           4
#define DUK_HBUFOBJ_ELEM_UINT32          5
#define DUK_HBUFOBJ_ELEM_INT32           6
#define DUK_HBUFOBJ_ELEM_FLOAT32         7
#define DUK_HBUFOBJ_ELEM_FLOAT64         8
#define DUK_HBUFOBJ_ELEM_MAX             8

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hbufobj_assert_valid(duk_hbufobj *h);
#define DUK_HBUFOBJ_ASSERT_VALID(h)  do { duk_hbufobj_assert_valid((h)); } while (0)
#else
#define DUK_HBUFOBJ_ASSERT_VALID(h)  do {} while (0)
#endif

/* Get the current data pointer (caller must ensure buf != NULL) as a
 * duk_uint8_t ptr.  Note that the result may be NULL if the underlying
 * buffer has zero size and is not a fixed buffer.
 */
#define DUK_HBUFOBJ_GET_SLICE_BASE(heap,h) \
	(DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
	(((duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR((heap), (h)->buf)) + (h)->offset))

/* True if slice is full, i.e. offset is zero and length covers the entire
 * buffer.  This status may change independently of the duk_hbufobj if
 * the underlying buffer is dynamic and changes without the hbufobj
 * being changed.
 */
#define DUK_HBUFOBJ_FULL_SLICE(h) \
	(DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
	((h)->offset == 0 && (h)->length == DUK_HBUFFER_GET_SIZE((h)->buf)))

/* Validate that the whole slice [0,length[ is contained in the underlying
 * buffer.  Caller must ensure 'buf' != NULL.
 */
#define DUK_HBUFOBJ_VALID_SLICE(h) \
	(DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
	((h)->offset + (h)->length <= DUK_HBUFFER_GET_SIZE((h)->buf)))

/* Validate byte read/write for virtual 'offset', i.e. check that the
 * offset, taking into account h->offset, is within the underlying
 * buffer size.  This is a safety check which is needed to ensure
 * that even a misconfigured duk_hbufobj never causes memory unsafe
 * behavior (e.g. if an underlying dynamic buffer changes after being
 * setup).  Caller must ensure 'buf' != NULL.
 */
#define DUK_HBUFOBJ_VALID_BYTEOFFSET_INCL(h,off) \
	(DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
	((h)->offset + (off) < DUK_HBUFFER_GET_SIZE((h)->buf)))

#define DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h,off) \
	(DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
	((h)->offset + (off) <= DUK_HBUFFER_GET_SIZE((h)->buf)))

/* Clamp an input byte length (already assumed to be within the nominal
 * duk_hbufobj 'length') to the current dynamic buffer limits to yield
 * a byte length limit that's safe for memory accesses.  This value can
 * be invalidated by any side effect because it may trigger a user
 * callback that resizes the underlying buffer.
 */
#define DUK_HBUFOBJ_CLAMP_BYTELENGTH(h,len) \
	(DUK_ASSERT_EXPR((h) != NULL), \
	duk_hbufobj_clamp_bytelength((h), (len)))

/* Typed arrays have virtual indices, ArrayBuffer and DataView do not. */
#define DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h)  ((h)->is_typedarray)

struct duk_hbufobj {
	/* Shared object part. */
	duk_hobject obj;

	/* Underlying buffer (refcounted), may be NULL. */
	duk_hbuffer *buf;

	/* .buffer reference to an ArrayBuffer, may be NULL. */
	duk_hobject *buf_prop;

	/* Slice and accessor information.
	 *
	 * Because the underlying buffer may be dynamic, these may be
	 * invalidated by the buffer being modified so that both offset
	 * and length should be validated before every access.  Behavior
	 * when the underlying buffer has changed doesn't need to be clean:
	 * virtual 'length' doesn't need to be affected, reads can return
	 * zero/NaN, and writes can be ignored.
	 *
	 * Note that a data pointer cannot be precomputed because 'buf' may
	 * be dynamic and its pointer unstable.
	 */

	duk_uint_t offset;       /* byte offset to buf */
	duk_uint_t length;       /* byte index limit for element access, exclusive */
	duk_uint8_t shift;       /* element size shift:
	                          *   0 = u8/i8
	                          *   1 = u16/i16
	                          *   2 = u32/i32/float
	                          *   3 = double
	                          */
	duk_uint8_t elem_type;   /* element type */
	duk_uint8_t is_typedarray;
};

DUK_INTERNAL_DECL duk_uint_t duk_hbufobj_clamp_bytelength(duk_hbufobj *h_bufobj, duk_uint_t len);
DUK_INTERNAL_DECL void duk_hbufobj_push_uint8array_from_plain(duk_hthread *thr, duk_hbuffer *h_buf);
DUK_INTERNAL_DECL void duk_hbufobj_push_validated_read(duk_hthread *thr, duk_hbufobj *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size);
DUK_INTERNAL_DECL void duk_hbufobj_validated_write(duk_hthread *thr, duk_hbufobj *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size);
DUK_INTERNAL_DECL void duk_hbufobj_promote_plain(duk_hthread *thr, duk_idx_t idx);

#else  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/* nothing */

#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
#endif  /* DUK_HBUFOBJ_H_INCLUDED */
/* #include duk_hthread.h */
/*
 *  Heap thread object representation.
 *
 *  duk_hthread is also the 'context' for public API functions via a
 *  different typedef.  Most API calls operate on the topmost frame
 *  of the value stack only.
 */

#if !defined(DUK_HTHREAD_H_INCLUDED)
#define DUK_HTHREAD_H_INCLUDED

/*
 *  Stack constants
 */

/* Initial valstack size, roughly 0.7kiB. */
#define DUK_VALSTACK_INITIAL_SIZE       96U

/* Internal extra elements assumed on function entry, always added to
 * user-defined 'extra' for e.g. the duk_check_stack() call.
 */
#define DUK_VALSTACK_INTERNAL_EXTRA     32U

/* Number of elements guaranteed to be user accessible (in addition to call
 * arguments) on Duktape/C function entry.  This is the major public API
 * commitment.
 */
#define DUK_VALSTACK_API_ENTRY_MINIMUM  DUK_API_ENTRY_STACK

/*
 *  Activation defines
 */

#define DUK_ACT_FLAG_STRICT             (1U << 0)  /* function executes in strict mode */
#define DUK_ACT_FLAG_TAILCALLED         (1U << 1)  /* activation has tail called one or more times */
#define DUK_ACT_FLAG_CONSTRUCT          (1U << 2)  /* function executes as a constructor (called via "new") */
#define DUK_ACT_FLAG_PREVENT_YIELD      (1U << 3)  /* activation prevents yield (native call or "new") */
#define DUK_ACT_FLAG_DIRECT_EVAL        (1U << 4)  /* activation is a direct eval call */
#define DUK_ACT_FLAG_CONSTRUCT_PROXY    (1U << 5)  /* activation is for Proxy 'construct' call, special return value handling */
#define DUK_ACT_FLAG_BREAKPOINT_ACTIVE  (1U << 6)  /* activation has active breakpoint(s) */

#define DUK_ACT_GET_FUNC(act)           ((act)->func)

/*
 *  Flags for __FILE__ / __LINE__ registered into tracedata
 */

#define DUK_TB_FLAG_NOBLAME_FILELINE    (1U << 0)  /* don't report __FILE__ / __LINE__ as fileName/lineNumber */

/*
 *  Catcher defines
 */

/* XXX: remove catcher type entirely */

/* flags field: LLLLLLFT, L = label (24 bits), F = flags (4 bits), T = type (4 bits) */
#define DUK_CAT_TYPE_MASK            0x0000000fUL
#define DUK_CAT_TYPE_BITS            4
#define DUK_CAT_LABEL_MASK           0xffffff00UL
#define DUK_CAT_LABEL_BITS           24
#define DUK_CAT_LABEL_SHIFT          8

#define DUK_CAT_FLAG_CATCH_ENABLED          (1U << 4)   /* catch part will catch */
#define DUK_CAT_FLAG_FINALLY_ENABLED        (1U << 5)   /* finally part will catch */
#define DUK_CAT_FLAG_CATCH_BINDING_ENABLED  (1U << 6)   /* request to create catch binding */
#define DUK_CAT_FLAG_LEXENV_ACTIVE          (1U << 7)   /* catch or with binding is currently active */

#define DUK_CAT_TYPE_UNKNOWN         0
#define DUK_CAT_TYPE_TCF             1
#define DUK_CAT_TYPE_LABEL           2

#define DUK_CAT_GET_TYPE(c)          ((c)->flags & DUK_CAT_TYPE_MASK)
#define DUK_CAT_GET_LABEL(c)         (((c)->flags & DUK_CAT_LABEL_MASK) >> DUK_CAT_LABEL_SHIFT)

#define DUK_CAT_HAS_CATCH_ENABLED(c)           ((c)->flags & DUK_CAT_FLAG_CATCH_ENABLED)
#define DUK_CAT_HAS_FINALLY_ENABLED(c)         ((c)->flags & DUK_CAT_FLAG_FINALLY_ENABLED)
#define DUK_CAT_HAS_CATCH_BINDING_ENABLED(c)   ((c)->flags & DUK_CAT_FLAG_CATCH_BINDING_ENABLED)
#define DUK_CAT_HAS_LEXENV_ACTIVE(c)           ((c)->flags & DUK_CAT_FLAG_LEXENV_ACTIVE)

#define DUK_CAT_SET_CATCH_ENABLED(c)    do { \
		(c)->flags |= DUK_CAT_FLAG_CATCH_ENABLED; \
	} while (0)
#define DUK_CAT_SET_FINALLY_ENABLED(c)  do { \
		(c)->flags |= DUK_CAT_FLAG_FINALLY_ENABLED; \
	} while (0)
#define DUK_CAT_SET_CATCH_BINDING_ENABLED(c)    do { \
		(c)->flags |= DUK_CAT_FLAG_CATCH_BINDING_ENABLED; \
	} while (0)
#define DUK_CAT_SET_LEXENV_ACTIVE(c)    do { \
		(c)->flags |= DUK_CAT_FLAG_LEXENV_ACTIVE; \
	} while (0)

#define DUK_CAT_CLEAR_CATCH_ENABLED(c)    do { \
		(c)->flags &= ~DUK_CAT_FLAG_CATCH_ENABLED; \
	} while (0)
#define DUK_CAT_CLEAR_FINALLY_ENABLED(c)  do { \
		(c)->flags &= ~DUK_CAT_FLAG_FINALLY_ENABLED; \
	} while (0)
#define DUK_CAT_CLEAR_CATCH_BINDING_ENABLED(c)    do { \
		(c)->flags &= ~DUK_CAT_FLAG_CATCH_BINDING_ENABLED; \
	} while (0)
#define DUK_CAT_CLEAR_LEXENV_ACTIVE(c)    do { \
		(c)->flags &= ~DUK_CAT_FLAG_LEXENV_ACTIVE; \
	} while (0)

/*
 *  Thread defines
 */

#if defined(DUK_USE_ROM_STRINGS)
#define DUK_HTHREAD_GET_STRING(thr,idx) \
	((duk_hstring *) DUK_LOSE_CONST(duk_rom_strings_stridx[(idx)]))
#else  /* DUK_USE_ROM_STRINGS */
#if defined(DUK_USE_HEAPPTR16)
#define DUK_HTHREAD_GET_STRING(thr,idx) \
	((duk_hstring *) DUK_USE_HEAPPTR_DEC16((thr)->heap->heap_udata, (thr)->strs16[(idx)]))
#else
#define DUK_HTHREAD_GET_STRING(thr,idx) \
	((thr)->strs[(idx)])
#endif
#endif  /* DUK_USE_ROM_STRINGS */

/* values for the state field */
#define DUK_HTHREAD_STATE_INACTIVE     1   /* thread not currently running */
#define DUK_HTHREAD_STATE_RUNNING      2   /* thread currently running (only one at a time) */
#define DUK_HTHREAD_STATE_RESUMED      3   /* thread resumed another thread (active but not running) */
#define DUK_HTHREAD_STATE_YIELDED      4   /* thread has yielded */
#define DUK_HTHREAD_STATE_TERMINATED   5   /* thread has terminated */

/* Executor interrupt default interval when nothing else requires a
 * smaller value.  The default interval must be small enough to allow
 * for reasonable execution timeout checking but large enough to keep
 * impact on execution performance low.
 */
#if defined(DUK_USE_INTERRUPT_COUNTER)
#define DUK_HTHREAD_INTCTR_DEFAULT     (256L * 1024L)
#endif

/*
 *  Assert context is valid: non-NULL pointer, fields look sane.
 *
 *  This is used by public API call entrypoints to catch invalid 'ctx' pointers
 *  as early as possible; invalid 'ctx' pointers cause very odd and difficult to
 *  diagnose behavior so it's worth checking even when the check is not 100%.
 */

#if defined(DUK_USE_ASSERTIONS)
/* Assertions for internals. */
DUK_INTERNAL_DECL void duk_hthread_assert_valid(duk_hthread *thr);
#define DUK_HTHREAD_ASSERT_VALID(thr)  do { duk_hthread_assert_valid((thr)); } while (0)

/* Assertions for public API calls; a bit stronger. */
DUK_INTERNAL_DECL void duk_ctx_assert_valid(duk_hthread *thr);
#define DUK_CTX_ASSERT_VALID(thr)  do { duk_ctx_assert_valid((thr)); } while (0)
#else
#define DUK_HTHREAD_ASSERT_VALID(thr)  do {} while (0)
#define DUK_CTX_ASSERT_VALID(thr)  do {} while (0)
#endif

/* Assertions for API call entry specifically.  Checks 'ctx' but also may
 * check internal state (e.g. not in a debugger transport callback).
 */
#define DUK_ASSERT_API_ENTRY(thr) do { \
		DUK_CTX_ASSERT_VALID((thr)); \
		DUK_ASSERT((thr)->heap != NULL); \
		DUK_ASSERT((thr)->heap->dbg_calling_transport == 0); \
	} while (0)

/*
 *  Assertion helpers.
 */

#define DUK_ASSERT_STRIDX_VALID(val) \
	DUK_ASSERT((duk_uint_t) (val) < DUK_HEAP_NUM_STRINGS)

#define DUK_ASSERT_BIDX_VALID(val) \
	DUK_ASSERT((duk_uint_t) (val) < DUK_NUM_BUILTINS)

/*
 *  Misc
 */

/* Fast access to 'this' binding.  Assumes there's a call in progress. */
#define DUK_HTHREAD_THIS_PTR(thr) \
	(DUK_ASSERT_EXPR((thr) != NULL), \
	 DUK_ASSERT_EXPR((thr)->valstack_bottom > (thr)->valstack), \
	 (thr)->valstack_bottom - 1)

/*
 *  Struct defines
 */

/* Fields are ordered for alignment/packing. */
struct duk_activation {
	duk_tval tv_func;       /* borrowed: full duk_tval for function being executed; for lightfuncs */
	duk_hobject *func;      /* borrowed: function being executed; for bound function calls, this is the final, real function, NULL for lightfuncs */
	duk_activation *parent; /* previous (parent) activation (or NULL if none) */
	duk_hobject *var_env;   /* current variable environment (may be NULL if delayed) */
	duk_hobject *lex_env;   /* current lexical environment (may be NULL if delayed) */
	duk_catcher *cat;       /* current catcher (or NULL) */

#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	/* Previous value of 'func' caller, restored when unwound.  Only in use
	 * when 'func' is non-strict.
	 */
	duk_hobject *prev_caller;
#endif

	duk_instr_t *curr_pc;   /* next instruction to execute (points to 'func' bytecode, stable pointer), NULL for native calls */

	/* bottom_byteoff and retval_byteoff are only used for book-keeping
	 * of ECMAScript-initiated calls, to allow returning to an ECMAScript
	 * function properly.
	 */

	/* Bottom of valstack for this activation, used to reset
	 * valstack_bottom on return; offset is absolute.  There's
	 * no need to track 'top' because native call handling deals
	 * with that using locals, and for ECMAScript returns 'nregs'
	 * indicates the necessary top.
	 */
	duk_size_t bottom_byteoff;

	/* Return value when returning to this activation (points to caller
	 * reg, not callee reg); offset is absolute (only set if activation is
	 * not topmost).
	 *
	 * Note: bottom_byteoff is always set, while retval_byteoff is only
	 * applicable for activations below the topmost one.  Currently
	 * retval_byteoff for the topmost activation is considered garbage
	 * (and it not initialized on entry or cleared on return; may contain
	 * previous or garbage values).
	 */
	duk_size_t retval_byteoff;

	/* Current 'this' binding is the value just below bottom.
	 * Previously, 'this' binding was handled with an index to the
	 * (calling) valstack.  This works for everything except tail
	 * calls, which must not "accumulate" valstack temps.
	 */

	/* Value stack reserve (valstack_end) byte offset to be restored
	 * when returning to this activation.  Only used by the bytecode
	 * executor.
	 */
	duk_size_t reserve_byteoff;

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_uint32_t prev_line; /* needed for stepping */
#endif

	duk_small_uint_t flags;
};

struct duk_catcher {
	duk_catcher *parent;            /* previous (parent) catcher (or NULL if none) */
	duk_hstring *h_varname;         /* borrowed reference to catch variable name (or NULL if none) */
	                                /* (reference is valid as long activation exists) */
	duk_instr_t *pc_base;           /* resume execution from pc_base or pc_base+1 (points to 'func' bytecode, stable pointer) */
	duk_size_t idx_base;            /* idx_base and idx_base+1 get completion value and type */
	duk_uint32_t flags;             /* type and control flags, label number */
	/* XXX: could pack 'flags' and 'idx_base' to same value in practice,
	 * on 32-bit targets this would make duk_catcher 16 bytes.
	 */
};

struct duk_hthread {
	/* Shared object part */
	duk_hobject obj;

	/* Pointer to bytecode executor's 'curr_pc' variable.  Used to copy
	 * the current PC back into the topmost activation when activation
	 * state is about to change (or "syncing" is otherwise needed).  This
	 * is rather awkward but important for performance, see execution.rst.
	 */
	duk_instr_t **ptr_curr_pc;

	/* Backpointers. */
	duk_heap *heap;

	/* Current strictness flag: affects API calls. */
	duk_uint8_t strict;

	/* Thread state. */
	duk_uint8_t state;
	duk_uint8_t unused1;
	duk_uint8_t unused2;

	/* XXX: Valstack and callstack are currently assumed to have non-NULL
	 * pointers.  Relaxing this would not lead to big benefits (except
	 * perhaps for terminated threads).
	 */

	/* Value stack: these are expressed as pointers for faster stack
	 * manipulation.  [valstack,valstack_top[ is GC-reachable,
	 * [valstack_top,valstack_alloc_end[ is not GC-reachable but kept
	 * initialized as 'undefined'.  [valstack,valstack_end[ is the
	 * guaranteed/reserved space and the valstack cannot be resized to
	 * a smaller size.  [valstack_end,valstack_alloc_end[ is currently
	 * allocated slack that can be used to grow the current guaranteed
	 * space but may be shrunk away without notice.
	 *
	 *
	 * <----------------------- guaranteed --->
	 *                                        <---- slack --->
	 *               <--- frame --->
	 * .-------------+=============+----------+--------------.
	 * |xxxxxxxxxxxxx|yyyyyyyyyyyyy|uuuuuuuuuu|uuuuuuuuuuuuuu|
	 * `-------------+=============+----------+--------------'
	 *
	 * ^             ^             ^          ^              ^
	 * |             |             |          |              |
	 * valstack      bottom        top        end            alloc_end
	 *
	 *     xxx = arbitrary values, below current frame
	 *     yyy = arbitrary values, inside current frame
	 *     uuu = outside active value stack, initialized to 'undefined'
	 */
	duk_tval *valstack;                     /* start of valstack allocation */
	duk_tval *valstack_end;                 /* end of valstack reservation/guarantee (exclusive) */
	duk_tval *valstack_alloc_end;           /* end of valstack allocation */
	duk_tval *valstack_bottom;              /* bottom of current frame */
	duk_tval *valstack_top;                 /* top of current frame (exclusive) */

	/* Call stack, represented as a linked list starting from the current
	 * activation (or NULL if nothing is active).
	 */
	duk_activation *callstack_curr;         /* current activation (or NULL if none) */
	duk_size_t callstack_top;               /* number of activation records in callstack (0 if none) */
	duk_size_t callstack_preventcount;      /* number of activation records in callstack preventing a yield */

	/* Yield/resume book-keeping. */
	duk_hthread *resumer;                   /* who resumed us (if any) */

	/* Current compiler state (if any), used for augmenting SyntaxErrors. */
	duk_compiler_ctx *compile_ctx;

#if defined(DUK_USE_INTERRUPT_COUNTER)
	/* Interrupt counter for triggering a slow path check for execution
	 * timeout, debugger interaction such as breakpoints, etc.  The value
	 * is valid for the current running thread, and both the init and
	 * counter values are copied whenever a thread switch occurs.  It's
	 * important for the counter to be conveniently accessible for the
	 * bytecode executor inner loop for performance reasons.
	 */
	duk_int_t interrupt_counter;    /* countdown state */
	duk_int_t interrupt_init;       /* start value for current countdown */
#endif

	/* Builtin-objects; may or may not be shared with other threads,
	 * threads existing in different "compartments" will have different
	 * built-ins.  Must be stored on a per-thread basis because there
	 * is no intermediate structure for a thread group / compartment.
	 * This takes quite a lot of space, currently 43x4 = 172 bytes on
	 * 32-bit platforms.
	 *
	 * In some cases the builtins array could be ROM based, but it's
	 * sometimes edited (e.g. for sandboxing) so it's better to keep
	 * this array in RAM.
	 */
	duk_hobject *builtins[DUK_NUM_BUILTINS];

	/* Convenience copies from heap/vm for faster access. */
#if defined(DUK_USE_ROM_STRINGS)
	/* No field needed when strings are in ROM. */
#else
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t *strs16;
#else
	duk_hstring **strs;
#endif
#endif
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL void duk_hthread_copy_builtin_objects(duk_hthread *thr_from, duk_hthread *thr_to);
DUK_INTERNAL_DECL void duk_hthread_create_builtin_objects(duk_hthread *thr);
DUK_INTERNAL_DECL duk_bool_t duk_hthread_init_stacks(duk_heap *heap, duk_hthread *thr);
DUK_INTERNAL_DECL void duk_hthread_terminate(duk_hthread *thr);

DUK_INTERNAL_DECL duk_activation *duk_hthread_activation_alloc(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_hthread_activation_free(duk_hthread *thr, duk_activation *act);
DUK_INTERNAL_DECL void duk_hthread_activation_unwind_norz(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_hthread_activation_unwind_reuse_norz(duk_hthread *thr);
DUK_INTERNAL_DECL duk_activation *duk_hthread_get_activation_for_level(duk_hthread *thr, duk_int_t level);

DUK_INTERNAL_DECL duk_catcher *duk_hthread_catcher_alloc(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_hthread_catcher_free(duk_hthread *thr, duk_catcher *cat);
DUK_INTERNAL_DECL void duk_hthread_catcher_unwind_norz(duk_hthread *thr, duk_activation *act);
DUK_INTERNAL_DECL void duk_hthread_catcher_unwind_nolexenv_norz(duk_hthread *thr, duk_activation *act);

#if defined(DUK_USE_FINALIZER_TORTURE)
DUK_INTERNAL_DECL void duk_hthread_valstack_torture_realloc(duk_hthread *thr);
#endif

DUK_INTERNAL_DECL void *duk_hthread_get_valstack_ptr(duk_heap *heap, void *ud);  /* indirect allocs */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL_DECL duk_uint_fast32_t duk_hthread_get_act_curr_pc(duk_hthread *thr, duk_activation *act);
#endif
DUK_INTERNAL_DECL duk_uint_fast32_t duk_hthread_get_act_prev_pc(duk_hthread *thr, duk_activation *act);
DUK_INTERNAL_DECL void duk_hthread_sync_currpc(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_hthread_sync_and_null_currpc(duk_hthread *thr);

#endif  /* DUK_HTHREAD_H_INCLUDED */
/* #include duk_harray.h */
/*
 *  Array object representation, used for actual Array instances.
 *
 *  All objects with the exotic array behavior (which must coincide with having
 *  internal class array) MUST be duk_harrays.  No other object can be a
 *  duk_harray.  However, duk_harrays may not always have an array part.
 */

#if !defined(DUK_HARRAY_H_INCLUDED)
#define DUK_HARRAY_H_INCLUDED

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_harray_assert_valid(duk_harray *h);
#define DUK_HARRAY_ASSERT_VALID(h)  do { duk_harray_assert_valid((h)); } while (0)
#else
#define DUK_HARRAY_ASSERT_VALID(h)  do {} while (0)
#endif

#define DUK_HARRAY_LENGTH_WRITABLE(h)         (!(h)->length_nonwritable)
#define DUK_HARRAY_LENGTH_NONWRITABLE(h)      ((h)->length_nonwritable)
#define DUK_HARRAY_SET_LENGTH_WRITABLE(h)     do { (h)->length_nonwritable = 0; } while (0)
#define DUK_HARRAY_SET_LENGTH_NONWRITABLE(h)  do { (h)->length_nonwritable = 1; } while (0)

struct duk_harray {
	/* Shared object part. */
	duk_hobject obj;

	/* Array .length.
	 *
	 * At present Array .length may be smaller, equal, or even larger
	 * than the allocated underlying array part.  Fast path code must
	 * always take this into account carefully.
	 */
	duk_uint32_t length;

	/* Array .length property attributes.  The property is always
	 * non-enumerable and non-configurable.  It's initially writable
	 * but per Object.defineProperty() rules it can be made non-writable
	 * even if it is non-configurable.  Thus we need to track the
	 * writability explicitly.
	 *
	 * XXX: this field to be eliminated and moved into duk_hobject
	 * flags field to save space.
	 */
	duk_bool_t length_nonwritable;
};

#endif  /* DUK_HARRAY_H_INCLUDED */
/* #include duk_henv.h */
/*
 *  Environment object representation.
 */

#if !defined(DUK_HENV_H_INCLUDED)
#define DUK_HENV_H_INCLUDED

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hdecenv_assert_valid(duk_hdecenv *h);
DUK_INTERNAL_DECL void duk_hobjenv_assert_valid(duk_hobjenv *h);
#define DUK_HDECENV_ASSERT_VALID(h)  do { duk_hdecenv_assert_valid((h)); } while (0)
#define DUK_HOBJENV_ASSERT_VALID(h)  do { duk_hobjenv_assert_valid((h)); } while (0)
#else
#define DUK_HDECENV_ASSERT_VALID(h)  do {} while (0)
#define DUK_HOBJENV_ASSERT_VALID(h)  do {} while (0)
#endif

struct duk_hdecenv {
	/* Shared object part. */
	duk_hobject obj;

	/* These control variables provide enough information to access live
	 * variables for a closure that is still open.  If thread == NULL,
	 * the record is closed and the identifiers are in the property table.
	 */
	duk_hthread *thread;
	duk_hobject *varmap;
	duk_size_t regbase_byteoff;
};

struct duk_hobjenv {
	/* Shared object part. */
	duk_hobject obj;

	/* Target object and 'this' binding for object binding. */
	duk_hobject *target;

	/* The 'target' object is used as a this binding in only some object
	 * environments.  For example, the global environment does not provide
	 * a this binding, but a with statement does.
	 */
	duk_bool_t has_this;
};

#endif  /* DUK_HENV_H_INCLUDED */
/* #include duk_hbuffer.h */
/*
 *  Heap buffer representation.
 *
 *  Heap allocated user data buffer which is either:
 *
 *    1. A fixed size buffer (data follows header statically)
 *    2. A dynamic size buffer (data pointer follows header)
 *
 *  The data pointer for a variable size buffer of zero size may be NULL.
 */

#if !defined(DUK_HBUFFER_H_INCLUDED)
#define DUK_HBUFFER_H_INCLUDED

/*
 *  Flags
 *
 *  Fixed buffer:     0
 *  Dynamic buffer:   DUK_HBUFFER_FLAG_DYNAMIC
 *  External buffer:  DUK_HBUFFER_FLAG_DYNAMIC | DUK_HBUFFER_FLAG_EXTERNAL
 */

#define DUK_HBUFFER_FLAG_DYNAMIC                  DUK_HEAPHDR_USER_FLAG(0)    /* buffer is behind a pointer, dynamic or external */
#define DUK_HBUFFER_FLAG_EXTERNAL                 DUK_HEAPHDR_USER_FLAG(1)    /* buffer pointer is to an externally allocated buffer */

#define DUK_HBUFFER_HAS_DYNAMIC(x)                DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_DYNAMIC)
#define DUK_HBUFFER_HAS_EXTERNAL(x)               DUK_HEAPHDR_CHECK_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_EXTERNAL)

#define DUK_HBUFFER_SET_DYNAMIC(x)                DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_DYNAMIC)
#define DUK_HBUFFER_SET_EXTERNAL(x)               DUK_HEAPHDR_SET_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_EXTERNAL)

#define DUK_HBUFFER_CLEAR_DYNAMIC(x)              DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_DYNAMIC)
#define DUK_HBUFFER_CLEAR_EXTERNAL(x)             DUK_HEAPHDR_CLEAR_FLAG_BITS(&(x)->hdr, DUK_HBUFFER_FLAG_EXTERNAL)

/*
 *  Misc defines
 */

/* Impose a maximum buffer length for now.  Restricted artificially to
 * ensure resize computations or adding a heap header length won't
 * overflow size_t and that a signed duk_int_t can hold a buffer
 * length.  The limit should be synchronized with DUK_HSTRING_MAX_BYTELEN.
 */

#if defined(DUK_USE_BUFLEN16)
#define DUK_HBUFFER_MAX_BYTELEN                   (0x0000ffffUL)
#else
/* Intentionally not 0x7fffffffUL; at least JSON code expects that
 * 2*len + 2 fits in 32 bits.
 */
#define DUK_HBUFFER_MAX_BYTELEN                   (0x7ffffffeUL)
#endif

/*
 *  Field access
 */

#if defined(DUK_USE_BUFLEN16)
/* size stored in duk_heaphdr unused flag bits */
#define DUK_HBUFFER_GET_SIZE(x)     ((x)->hdr.h_flags >> 16)
#define DUK_HBUFFER_SET_SIZE(x,v)   do { \
		duk_size_t duk__v; \
		duk__v = (v); \
		DUK_ASSERT(duk__v <= 0xffffUL); \
		(x)->hdr.h_flags = ((x)->hdr.h_flags & 0x0000ffffUL) | (((duk_uint32_t) duk__v) << 16); \
	} while (0)
#define DUK_HBUFFER_ADD_SIZE(x,dv)  do { \
		(x)->hdr.h_flags += ((dv) << 16); \
	} while (0)
#define DUK_HBUFFER_SUB_SIZE(x,dv)  do { \
		(x)->hdr.h_flags -= ((dv) << 16); \
	} while (0)
#else
#define DUK_HBUFFER_GET_SIZE(x)     (((duk_hbuffer *) (x))->size)
#define DUK_HBUFFER_SET_SIZE(x,v)   do { \
		((duk_hbuffer *) (x))->size = (v); \
	} while (0)
#define DUK_HBUFFER_ADD_SIZE(x,dv)  do { \
		(x)->size += (dv); \
	} while (0)
#define DUK_HBUFFER_SUB_SIZE(x,dv)  do { \
		(x)->size -= (dv); \
	} while (0)
#endif

#define DUK_HBUFFER_FIXED_GET_SIZE(x)       DUK_HBUFFER_GET_SIZE((duk_hbuffer *) (x))
#define DUK_HBUFFER_FIXED_SET_SIZE(x,v)     DUK_HBUFFER_SET_SIZE((duk_hbuffer *) (x))

#define DUK_HBUFFER_DYNAMIC_GET_SIZE(x)     DUK_HBUFFER_GET_SIZE((duk_hbuffer *) (x))
#define DUK_HBUFFER_DYNAMIC_SET_SIZE(x,v)   DUK_HBUFFER_SET_SIZE((duk_hbuffer *) (x), (v))
#define DUK_HBUFFER_DYNAMIC_ADD_SIZE(x,dv)  DUK_HBUFFER_ADD_SIZE((duk_hbuffer *) (x), (dv))
#define DUK_HBUFFER_DYNAMIC_SUB_SIZE(x,dv)  DUK_HBUFFER_SUB_SIZE((duk_hbuffer *) (x), (dv))

#define DUK_HBUFFER_EXTERNAL_GET_SIZE(x)    DUK_HBUFFER_GET_SIZE((duk_hbuffer *) (x))
#define DUK_HBUFFER_EXTERNAL_SET_SIZE(x,v)  DUK_HBUFFER_SET_SIZE((duk_hbuffer *) (x), (v))

#define DUK_HBUFFER_FIXED_GET_DATA_PTR(heap,x)    ((duk_uint8_t *) (((duk_hbuffer_fixed *) (void *) (x)) + 1))

#if defined(DUK_USE_HEAPPTR16)
#define DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap,x) \
	((void *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, ((duk_heaphdr *) (x))->h_extra16))
#define DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap,x,v)     do { \
		((duk_heaphdr *) (x))->h_extra16 = DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (void *) (v)); \
	} while (0)
#define DUK_HBUFFER_DYNAMIC_SET_DATA_PTR_NULL(heap,x)  do { \
		((duk_heaphdr *) (x))->h_extra16 = 0;  /* assume 0 <=> NULL */ \
	} while (0)
#else
#define DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap,x)       ((x)->curr_alloc)
#define DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap,x,v)     do { \
		(x)->curr_alloc = (void *) (v); \
	} while (0)
#define DUK_HBUFFER_DYNAMIC_SET_DATA_PTR_NULL(heap,x)  do { \
		(x)->curr_alloc = (void *) NULL; \
	} while (0)
#endif

/* No pointer compression because pointer is potentially outside of
 * Duktape heap.
 */
#if defined(DUK_USE_HEAPPTR16)
#define DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(heap,x) \
	((void *) (x)->curr_alloc)
#define DUK_HBUFFER_EXTERNAL_SET_DATA_PTR(heap,x,v)     do { \
		(x)->curr_alloc = (void *) (v); \
	} while (0)
#define DUK_HBUFFER_EXTERNAL_SET_DATA_PTR_NULL(heap,x)  do { \
		(x)->curr_alloc = (void *) NULL; \
	} while (0)
#else
#define DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(heap,x) \
	((void *) (x)->curr_alloc)
#define DUK_HBUFFER_EXTERNAL_SET_DATA_PTR(heap,x,v)     do { \
		(x)->curr_alloc = (void *) (v); \
	} while (0)
#define DUK_HBUFFER_EXTERNAL_SET_DATA_PTR_NULL(heap,x)  do { \
		(x)->curr_alloc = (void *) NULL; \
	} while (0)
#endif

/* Get a pointer to the current buffer contents (matching current allocation
 * size).  May be NULL for zero size dynamic/external buffer.
 */
#if defined(DUK_USE_HEAPPTR16)
#define DUK_HBUFFER_GET_DATA_PTR(heap,x)  ( \
	DUK_HBUFFER_HAS_DYNAMIC((x)) ? \
		( \
			DUK_HBUFFER_HAS_EXTERNAL((x)) ? \
				DUK_HBUFFER_EXTERNAL_GET_DATA_PTR((heap), (duk_hbuffer_external *) (x)) : \
				DUK_HBUFFER_DYNAMIC_GET_DATA_PTR((heap), (duk_hbuffer_dynamic *) (x)) \
		) : \
		DUK_HBUFFER_FIXED_GET_DATA_PTR((heap), (duk_hbuffer_fixed *) (void *) (x)) \
	)
#else
/* Without heap pointer compression duk_hbuffer_dynamic and duk_hbuffer_external
 * have the same layout so checking for fixed vs. dynamic (or external) is enough.
 */
#define DUK_HBUFFER_GET_DATA_PTR(heap,x)  ( \
	DUK_HBUFFER_HAS_DYNAMIC((x)) ? \
		DUK_HBUFFER_DYNAMIC_GET_DATA_PTR((heap), (duk_hbuffer_dynamic *) (x)) : \
		DUK_HBUFFER_FIXED_GET_DATA_PTR((heap), (duk_hbuffer_fixed *) (void *) (x)) \
	)
#endif

/* Validity assert. */
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hbuffer_assert_valid(duk_hbuffer *h);
#define DUK_HBUFFER_ASSERT_VALID(h)  do { duk_hbuffer_assert_valid((h)); } while (0)
#else
#define DUK_HBUFFER_ASSERT_VALID(h)  do {} while (0)
#endif

/*
 *  Structs
 */

/* Shared prefix for all buffer types. */
struct duk_hbuffer {
	duk_heaphdr hdr;

	/* It's not strictly necessary to track the current size, but
	 * it is useful for writing robust native code.
	 */

	/* Current size. */
#if defined(DUK_USE_BUFLEN16)
	/* Stored in duk_heaphdr unused flags. */
#else
	duk_size_t size;
#endif

	/*
	 *  Data following the header depends on the DUK_HBUFFER_FLAG_DYNAMIC
	 *  flag.
	 *
	 *  If the flag is clear (the buffer is a fixed size one), the buffer
	 *  data follows the header directly, consisting of 'size' bytes.
	 *
	 *  If the flag is set, the actual buffer is allocated separately, and
	 *  a few control fields follow the header.  Specifically:
	 *
	 *    - a "void *" pointing to the current allocation
	 *    - a duk_size_t indicating the full allocated size (always >= 'size')
	 *
	 *  If DUK_HBUFFER_FLAG_EXTERNAL is set, the buffer has been allocated
	 *  by user code, so that Duktape won't be able to resize it and won't
	 *  free it.  This allows buffers to point to e.g. an externally
	 *  allocated structure such as a frame buffer.
	 *
	 *  Unlike strings, no terminator byte (NUL) is guaranteed after the
	 *  data.  This would be convenient, but would pad aligned user buffers
	 *  unnecessarily upwards in size.  For instance, if user code requested
	 *  a 64-byte dynamic buffer, 65 bytes would actually be allocated which
	 *  would then potentially round upwards to perhaps 68 or 72 bytes.
	 */
};

/* Fixed buffer; data follows struct, with proper alignment guaranteed by
 * struct size.
 */
#if (DUK_USE_ALIGN_BY == 8) && defined(DUK_USE_PACK_MSVC_PRAGMA)
#pragma pack(push, 8)
#endif
struct duk_hbuffer_fixed {
	/* A union is used here as a portable struct size / alignment trick:
	 * by adding a 32-bit or a 64-bit (unused) union member, the size of
	 * the struct is effectively forced to be a multiple of 4 or 8 bytes
	 * (respectively) without increasing the size of the struct unless
	 * necessary.
	 */
	union {
		struct {
			duk_heaphdr hdr;
#if defined(DUK_USE_BUFLEN16)
			/* Stored in duk_heaphdr unused flags. */
#else
			duk_size_t size;
#endif
		} s;
#if (DUK_USE_ALIGN_BY == 4)
		duk_uint32_t dummy_for_align4;
#elif (DUK_USE_ALIGN_BY == 8)
		duk_double_t dummy_for_align8_1;
#if defined(DUK_USE_64BIT_OPS)
		duk_uint64_t dummy_for_align8_2;
#endif
#elif (DUK_USE_ALIGN_BY == 1)
		/* no extra padding */
#else
#error invalid DUK_USE_ALIGN_BY
#endif
	} u;

	/*
	 *  Data follows the struct header.  The struct size is padded by the
	 *  compiler based on the struct members.  This guarantees that the
	 *  buffer data will be aligned-by-4 but not necessarily aligned-by-8.
	 *
	 *  On platforms where alignment does not matter, the struct padding
	 *  could be removed (if there is any).  On platforms where alignment
	 *  by 8 is required, the struct size must be forced to be a multiple
	 *  of 8 by some means.  Without it, some user code may break, and also
	 *  Duktape itself breaks (e.g. the compiler stores duk_tvals in a
	 *  dynamic buffer).
	 */
}
#if (DUK_USE_ALIGN_BY == 8) && defined(DUK_USE_PACK_GCC_ATTR)
__attribute__ ((aligned (8)))
#elif (DUK_USE_ALIGN_BY == 8) && defined(DUK_USE_PACK_CLANG_ATTR)
__attribute__ ((aligned (8)))
#endif
;
#if (DUK_USE_ALIGN_BY == 8) && defined(DUK_USE_PACK_MSVC_PRAGMA)
#pragma pack(pop)
#endif

/* Dynamic buffer with 'curr_alloc' pointing to a dynamic area allocated using
 * heap allocation primitives.  Also used for external buffers when low memory
 * options are not used.
 */
struct duk_hbuffer_dynamic {
	duk_heaphdr hdr;

#if defined(DUK_USE_BUFLEN16)
	/* Stored in duk_heaphdr unused flags. */
#else
	duk_size_t size;
#endif

#if defined(DUK_USE_HEAPPTR16)
	/* Stored in duk_heaphdr h_extra16. */
#else
	void *curr_alloc;  /* may be NULL if alloc_size == 0 */
#endif

	/*
	 *  Allocation size for 'curr_alloc' is alloc_size.  There is no
	 *  automatic NUL terminator for buffers (see above for rationale).
	 *
	 *  'curr_alloc' is explicitly allocated with heap allocation
	 *  primitives and will thus always have alignment suitable for
	 *  e.g. duk_tval and an IEEE double.
	 */
};

/* External buffer with 'curr_alloc' managed by user code and pointing to an
 * arbitrary address.  When heap pointer compression is not used, this struct
 * has the same layout as duk_hbuffer_dynamic.
 */
struct duk_hbuffer_external {
	duk_heaphdr hdr;

#if defined(DUK_USE_BUFLEN16)
	/* Stored in duk_heaphdr unused flags. */
#else
	duk_size_t size;
#endif

	/* Cannot be compressed as a heap pointer because may point to
	 * an arbitrary address.
	 */
	void *curr_alloc;  /* may be NULL if alloc_size == 0 */
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL duk_hbuffer *duk_hbuffer_alloc(duk_heap *heap, duk_size_t size, duk_small_uint_t flags, void **out_bufdata);
DUK_INTERNAL_DECL void *duk_hbuffer_get_dynalloc_ptr(duk_heap *heap, void *ud);  /* indirect allocs */

/* dynamic buffer ops */
DUK_INTERNAL_DECL void duk_hbuffer_resize(duk_hthread *thr, duk_hbuffer_dynamic *buf, duk_size_t new_size);
DUK_INTERNAL_DECL void duk_hbuffer_reset(duk_hthread *thr, duk_hbuffer_dynamic *buf);

#endif  /* DUK_HBUFFER_H_INCLUDED */
/* #include duk_hproxy.h */
/*
 *  Proxy object representation.
 */

#if !defined(DUK_HPROXY_H_INCLUDED)
#define DUK_HPROXY_H_INCLUDED

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_hproxy_assert_valid(duk_hproxy *h);
#define DUK_HPROXY_ASSERT_VALID(h)  do { duk_hproxy_assert_valid((h)); } while (0)
#else
#define DUK_HPROXY_ASSERT_VALID(h)  do {} while (0)
#endif

struct duk_hproxy {
	/* Shared object part. */
	duk_hobject obj;

	/* Proxy target object. */
	duk_hobject *target;

	/* Proxy handlers (traps). */
	duk_hobject *handler;
};

#endif  /* DUK_HPROXY_H_INCLUDED */
/* #include duk_heap.h */
/*
 *  Heap structure.
 *
 *  Heap contains allocated heap objects, interned strings, and built-in
 *  strings for one or more threads.
 */

#if !defined(DUK_HEAP_H_INCLUDED)
#define DUK_HEAP_H_INCLUDED

/* alloc function typedefs in duktape.h */

/*
 *  Heap flags
 */

#define DUK_HEAP_FLAG_MARKANDSWEEP_RECLIMIT_REACHED            (1U << 0)  /* mark-and-sweep marking reached a recursion limit and must use multi-pass marking */
#define DUK_HEAP_FLAG_INTERRUPT_RUNNING                        (1U << 1)  /* executor interrupt running (used to avoid nested interrupts) */
#define DUK_HEAP_FLAG_FINALIZER_NORESCUE                       (1U << 2)  /* heap destruction ongoing, finalizer rescue no longer possible */
#define DUK_HEAP_FLAG_DEBUGGER_PAUSED                          (1U << 3)  /* debugger is paused: talk with debug client until step/resume */

#define DUK__HEAP_HAS_FLAGS(heap,bits)               ((heap)->flags & (bits))
#define DUK__HEAP_SET_FLAGS(heap,bits)  do { \
		(heap)->flags |= (bits); \
	} while (0)
#define DUK__HEAP_CLEAR_FLAGS(heap,bits)  do { \
		(heap)->flags &= ~(bits); \
	} while (0)

#define DUK_HEAP_HAS_MARKANDSWEEP_RECLIMIT_REACHED(heap)   DUK__HEAP_HAS_FLAGS((heap), DUK_HEAP_FLAG_MARKANDSWEEP_RECLIMIT_REACHED)
#define DUK_HEAP_HAS_INTERRUPT_RUNNING(heap)               DUK__HEAP_HAS_FLAGS((heap), DUK_HEAP_FLAG_INTERRUPT_RUNNING)
#define DUK_HEAP_HAS_FINALIZER_NORESCUE(heap)              DUK__HEAP_HAS_FLAGS((heap), DUK_HEAP_FLAG_FINALIZER_NORESCUE)
#define DUK_HEAP_HAS_DEBUGGER_PAUSED(heap)                 DUK__HEAP_HAS_FLAGS((heap), DUK_HEAP_FLAG_DEBUGGER_PAUSED)

#define DUK_HEAP_SET_MARKANDSWEEP_RECLIMIT_REACHED(heap)   DUK__HEAP_SET_FLAGS((heap), DUK_HEAP_FLAG_MARKANDSWEEP_RECLIMIT_REACHED)
#define DUK_HEAP_SET_INTERRUPT_RUNNING(heap)               DUK__HEAP_SET_FLAGS((heap), DUK_HEAP_FLAG_INTERRUPT_RUNNING)
#define DUK_HEAP_SET_FINALIZER_NORESCUE(heap)              DUK__HEAP_SET_FLAGS((heap), DUK_HEAP_FLAG_FINALIZER_NORESCUE)
#define DUK_HEAP_SET_DEBUGGER_PAUSED(heap)                 DUK__HEAP_SET_FLAGS((heap), DUK_HEAP_FLAG_DEBUGGER_PAUSED)

#define DUK_HEAP_CLEAR_MARKANDSWEEP_RECLIMIT_REACHED(heap) DUK__HEAP_CLEAR_FLAGS((heap), DUK_HEAP_FLAG_MARKANDSWEEP_RECLIMIT_REACHED)
#define DUK_HEAP_CLEAR_INTERRUPT_RUNNING(heap)             DUK__HEAP_CLEAR_FLAGS((heap), DUK_HEAP_FLAG_INTERRUPT_RUNNING)
#define DUK_HEAP_CLEAR_FINALIZER_NORESCUE(heap)            DUK__HEAP_CLEAR_FLAGS((heap), DUK_HEAP_FLAG_FINALIZER_NORESCUE)
#define DUK_HEAP_CLEAR_DEBUGGER_PAUSED(heap)               DUK__HEAP_CLEAR_FLAGS((heap), DUK_HEAP_FLAG_DEBUGGER_PAUSED)

/*
 *  Longjmp types, also double as identifying continuation type for a rethrow (in 'finally')
 */

#define DUK_LJ_TYPE_UNKNOWN      0    /* unused */
#define DUK_LJ_TYPE_THROW        1    /* value1 -> error object */
#define DUK_LJ_TYPE_YIELD        2    /* value1 -> yield value, iserror -> error / normal */
#define DUK_LJ_TYPE_RESUME       3    /* value1 -> resume value, value2 -> resumee thread, iserror -> error/normal */
#define DUK_LJ_TYPE_BREAK        4    /* value1 -> label number, pseudo-type to indicate a break continuation (for ENDFIN) */
#define DUK_LJ_TYPE_CONTINUE     5    /* value1 -> label number, pseudo-type to indicate a continue continuation (for ENDFIN) */
#define DUK_LJ_TYPE_RETURN       6    /* value1 -> return value, pseudo-type to indicate a return continuation (for ENDFIN) */
#define DUK_LJ_TYPE_NORMAL       7    /* no value, pseudo-type to indicate a normal continuation (for ENDFIN) */

/*
 *  Mark-and-sweep flags
 *
 *  These are separate from heap level flags now but could be merged.
 *  The heap structure only contains a 'base mark-and-sweep flags'
 *  field and the GC caller can impose further flags.
 */

/* Emergency mark-and-sweep: try extra hard, even at the cost of
 * performance.
 */
#define DUK_MS_FLAG_EMERGENCY                (1U << 0)

/* Postpone rescue decisions for reachable objects with FINALIZED set.
 * Used during finalize_list processing to avoid incorrect rescue
 * decisions due to finalize_list being a reachability root.
 */
#define DUK_MS_FLAG_POSTPONE_RESCUE          (1U << 1)

/* Don't compact objects; needed during object property table resize
 * to prevent a recursive resize.  It would suffice to protect only the
 * current object being resized, but this is not yet implemented.
 */
#define DUK_MS_FLAG_NO_OBJECT_COMPACTION     (1U << 2)

/*
 *  Thread switching
 *
 *  To switch heap->curr_thread, use the macro below so that interrupt counters
 *  get updated correctly.  The macro allows a NULL target thread because that
 *  happens e.g. in call handling.
 */

#if defined(DUK_USE_INTERRUPT_COUNTER)
#define DUK_HEAP_SWITCH_THREAD(heap,newthr)  duk_heap_switch_thread((heap), (newthr))
#else
#define DUK_HEAP_SWITCH_THREAD(heap,newthr)  do { \
		(heap)->curr_thread = (newthr); \
	} while (0)
#endif

/*
 *  Stats
 */

#if defined(DUK_USE_DEBUG)
#define DUK_STATS_INC(heap,fieldname) do { \
		(heap)->fieldname += 1; \
	} while (0)
#else
#define DUK_STATS_INC(heap,fieldname) do {} while (0)
#endif

/*
 *  Other heap related defines
 */

/* Mark-and-sweep interval is relative to combined count of objects and
 * strings kept in the heap during the latest mark-and-sweep pass.
 * Fixed point .8 multiplier and .0 adder.  Trigger count (interval) is
 * decreased by each (re)allocation attempt (regardless of size), and each
 * refzero processed object.
 *
 * 'SKIP' indicates how many (re)allocations to wait until a retry if
 * GC is skipped because there is no thread do it with yet (happens
 * only during init phases).
 */
#if defined(DUK_USE_REFERENCE_COUNTING)
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_MULT              12800L  /* 50x heap size */
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_ADD               1024L
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_SKIP              256L
#else
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_MULT              256L    /* 1x heap size */
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_ADD               1024L
#define DUK_HEAP_MARK_AND_SWEEP_TRIGGER_SKIP              256L
#endif

/* GC torture. */
#if defined(DUK_USE_GC_TORTURE)
#define DUK_GC_TORTURE(heap) do { duk_heap_mark_and_sweep((heap), 0); } while (0)
#else
#define DUK_GC_TORTURE(heap) do { } while (0)
#endif

/* Stringcache is used for speeding up char-offset-to-byte-offset
 * translations for non-ASCII strings.
 */
#define DUK_HEAP_STRCACHE_SIZE                            4
#define DUK_HEAP_STRINGCACHE_NOCACHE_LIMIT                16  /* strings up to the this length are not cached */

/* Some list management macros. */
#define DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap,hdr)     duk_heap_insert_into_heap_allocated((heap), (hdr))
#if defined(DUK_USE_REFERENCE_COUNTING)
#define DUK_HEAP_REMOVE_FROM_HEAP_ALLOCATED(heap,hdr)     duk_heap_remove_from_heap_allocated((heap), (hdr))
#endif
#if defined(DUK_USE_FINALIZER_SUPPORT)
#define DUK_HEAP_INSERT_INTO_FINALIZE_LIST(heap,hdr)      duk_heap_insert_into_finalize_list((heap), (hdr))
#define DUK_HEAP_REMOVE_FROM_FINALIZE_LIST(heap,hdr)      duk_heap_remove_from_finalize_list((heap), (hdr))
#endif

/*
 *  Built-in strings
 */

/* heap string indices are autogenerated in duk_strings.h */
#if defined(DUK_USE_ROM_STRINGS)
#define DUK_HEAP_GET_STRING(heap,idx) \
	((duk_hstring *) DUK_LOSE_CONST(duk_rom_strings_stridx[(idx)]))
#else  /* DUK_USE_ROM_STRINGS */
#if defined(DUK_USE_HEAPPTR16)
#define DUK_HEAP_GET_STRING(heap,idx) \
	((duk_hstring *) DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (heap)->strs16[(idx)]))
#else
#define DUK_HEAP_GET_STRING(heap,idx) \
	((heap)->strs[(idx)])
#endif
#endif  /* DUK_USE_ROM_STRINGS */

/*
 *  Raw memory calls: relative to heap, but no GC interaction
 */

#define DUK_ALLOC_RAW(heap,size) \
	((heap)->alloc_func((heap)->heap_udata, (size)))

#define DUK_REALLOC_RAW(heap,ptr,newsize) \
	((heap)->realloc_func((heap)->heap_udata, (void *) (ptr), (newsize)))

#define DUK_FREE_RAW(heap,ptr) \
	((heap)->free_func((heap)->heap_udata, (void *) (ptr)))

/*
 *  Memory calls: relative to heap, GC interaction, but no error throwing.
 *
 *  XXX: Currently a mark-and-sweep triggered by memory allocation will run
 *  using the heap->heap_thread.  This thread is also used for running
 *  mark-and-sweep finalization; this is not ideal because it breaks the
 *  isolation between multiple global environments.
 *
 *  Notes:
 *
 *    - DUK_FREE() is required to ignore NULL and any other possible return
 *      value of a zero-sized alloc/realloc (same as ANSI C free()).
 *
 *    - There is no DUK_REALLOC_ZEROED because we don't assume to know the
 *      old size.  Caller must zero the reallocated memory.
 *
 *    - DUK_REALLOC_INDIRECT() must be used when a mark-and-sweep triggered
 *      by an allocation failure might invalidate the original 'ptr', thus
 *      causing a realloc retry to use an invalid pointer.  Example: we're
 *      reallocating the value stack and a finalizer resizes the same value
 *      stack during mark-and-sweep.  The indirect variant requests for the
 *      current location of the pointer being reallocated using a callback
 *      right before every realloc attempt; this circuitous approach is used
 *      to avoid strict aliasing issues in a more straightforward indirect
 *      pointer (void **) approach.  Note: the pointer in the storage
 *      location is read but is NOT updated; the caller must do that.
 */

/* callback for indirect reallocs, request for current pointer */
typedef void *(*duk_mem_getptr)(duk_heap *heap, void *ud);

#define DUK_ALLOC(heap,size)                            duk_heap_mem_alloc((heap), (size))
#define DUK_ALLOC_ZEROED(heap,size)                     duk_heap_mem_alloc_zeroed((heap), (size))
#define DUK_REALLOC(heap,ptr,newsize)                   duk_heap_mem_realloc((heap), (ptr), (newsize))
#define DUK_REALLOC_INDIRECT(heap,cb,ud,newsize)        duk_heap_mem_realloc_indirect((heap), (cb), (ud), (newsize))
#define DUK_FREE(heap,ptr)                              duk_heap_mem_free((heap), (ptr))

/*
 *  Checked allocation, relative to a thread
 *
 *  DUK_FREE_CHECKED() doesn't actually throw, but accepts a 'thr' argument
 *  for convenience.
 */

#define DUK_ALLOC_CHECKED(thr,size)                     duk_heap_mem_alloc_checked((thr), (size))
#define DUK_ALLOC_CHECKED_ZEROED(thr,size)              duk_heap_mem_alloc_checked_zeroed((thr), (size))
#define DUK_FREE_CHECKED(thr,ptr)                       duk_heap_mem_free((thr)->heap, (ptr))

/*
 *  Memory constants
 */

#define DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_LIMIT           10  /* Retry allocation after mark-and-sweep for this
                                                              * many times.  A single mark-and-sweep round is
                                                              * not guaranteed to free all unreferenced memory
                                                              * because of finalization (in fact, ANY number of
                                                              * rounds is strictly not enough).
                                                              */

#define DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_EMERGENCY_LIMIT  3  /* Starting from this round, use emergency mode
                                                              * for mark-and-sweep.
                                                              */

/*
 *  Debugger support
 */

/* Maximum number of breakpoints.  Only breakpoints that are set are
 * consulted so increasing this has no performance impact.
 */
#define DUK_HEAP_MAX_BREAKPOINTS          16

/* Opcode interval for a Date-based status/peek rate limit check.  Only
 * relevant when debugger is attached.  Requesting a timestamp may be a
 * slow operation on some platforms so this shouldn't be too low.  On the
 * other hand a high value makes Duktape react to a pause request slowly.
 */
#define DUK_HEAP_DBG_RATELIMIT_OPCODES    4000

/* Milliseconds between status notify and transport peeks. */
#define DUK_HEAP_DBG_RATELIMIT_MILLISECS  200

/* Debugger pause flags. */
#define DUK_PAUSE_FLAG_ONE_OPCODE        (1U << 0)   /* pause when a single opcode has been executed */
#define DUK_PAUSE_FLAG_ONE_OPCODE_ACTIVE (1U << 1)   /* one opcode pause actually active; artifact of current implementation */
#define DUK_PAUSE_FLAG_LINE_CHANGE       (1U << 2)   /* pause when current line number changes */
#define DUK_PAUSE_FLAG_FUNC_ENTRY        (1U << 3)   /* pause when entering a function */
#define DUK_PAUSE_FLAG_FUNC_EXIT         (1U << 4)   /* pause when exiting current function */
#define DUK_PAUSE_FLAG_CAUGHT_ERROR      (1U << 5)   /* pause when about to throw an error that is caught */
#define DUK_PAUSE_FLAG_UNCAUGHT_ERROR    (1U << 6)   /* pause when about to throw an error that won't be caught */

struct duk_breakpoint {
	duk_hstring *filename;
	duk_uint32_t line;
};

/*
 *  String cache should ideally be at duk_hthread level, but that would
 *  cause string finalization to slow down relative to the number of
 *  threads; string finalization must check the string cache for "weak"
 *  references to the string being finalized to avoid dead pointers.
 *
 *  Thus, string caches are now at the heap level now.
 */

struct duk_strcache_entry {
	duk_hstring *h;
	duk_uint32_t bidx;
	duk_uint32_t cidx;
};

/*
 *  Longjmp state, contains the information needed to perform a longjmp.
 *  Longjmp related values are written to value1, value2, and iserror.
 */

struct duk_ljstate {
	duk_jmpbuf *jmpbuf_ptr;   /* current setjmp() catchpoint */
	duk_small_uint_t type;    /* longjmp type */
	duk_bool_t iserror;       /* isError flag for yield */
	duk_tval value1;          /* 1st related value (type specific) */
	duk_tval value2;          /* 2nd related value (type specific) */
};

#define DUK_ASSERT_LJSTATE_UNSET(heap) do { \
		DUK_ASSERT(heap != NULL); \
		DUK_ASSERT(heap->lj.type == DUK_LJ_TYPE_UNKNOWN); \
		DUK_ASSERT(heap->lj.iserror == 0); \
		DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&heap->lj.value1)); \
		DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&heap->lj.value2)); \
	} while (0)
#define DUK_ASSERT_LJSTATE_SET(heap) do { \
		DUK_ASSERT(heap != NULL); \
		DUK_ASSERT(heap->lj.type != DUK_LJ_TYPE_UNKNOWN); \
	} while (0)

/*
 *  Literal intern cache
 */

struct duk_litcache_entry {
	const duk_uint8_t *addr;
	duk_hstring *h;
};

/*
 *  Main heap structure
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL void duk_heap_assert_valid(duk_heap *heap);
#define DUK_HEAP_ASSERT_VALID(heap)  do { duk_heap_assert_valid((heap)); } while (0)
#else
#define DUK_HEAP_ASSERT_VALID(heap)  do {} while (0)
#endif

struct duk_heap {
	duk_small_uint_t flags;

	/* Allocator functions. */
	duk_alloc_function alloc_func;
	duk_realloc_function realloc_func;
	duk_free_function free_func;

	/* Heap udata, used for allocator functions but also for other heap
	 * level callbacks like fatal function, pointer compression, etc.
	 */
	void *heap_udata;

	/* Fatal error handling, called e.g. when a longjmp() is needed but
	 * lj.jmpbuf_ptr is NULL.  fatal_func must never return; it's not
	 * declared as "noreturn" because doing that for typedefs is a bit
	 * challenging portability-wise.
	 */
	duk_fatal_function fatal_func;

	/* Main list of allocated heap objects.  Objects are either here,
	 * in finalize_list waiting for processing, or in refzero_list
	 * temporarily while a DECREF refzero cascade finishes.
	 */
	duk_heaphdr *heap_allocated;

	/* Temporary work list for freeing a cascade of objects when a DECREF
	 * (or DECREF_NORZ) encounters a zero refcount.  Using a work list
	 * allows fixed C stack size when refcounts go to zero for a chain of
	 * objects.  Outside of DECREF this is always a NULL because DECREF is
	 * processed without side effects (only memory free calls).
	 */
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_heaphdr *refzero_list;
#endif

#if defined(DUK_USE_FINALIZER_SUPPORT)
	/* Work list for objects to be finalized. */
	duk_heaphdr *finalize_list;
#if defined(DUK_USE_ASSERTIONS)
	/* Object whose finalizer is executing right now (no nesting). */
	duk_heaphdr *currently_finalizing;
#endif
#endif

	/* Freelist for duk_activations and duk_catchers. */
#if defined(DUK_USE_CACHE_ACTIVATION)
	duk_activation *activation_free;
#endif
#if defined(DUK_USE_CACHE_CATCHER)
	duk_catcher *catcher_free;
#endif

	/* Voluntary mark-and-sweep trigger counter.  Intentionally signed
	 * because we continue decreasing the value when voluntary GC cannot
	 * run.
	 */
#if defined(DUK_USE_VOLUNTARY_GC)
	duk_int_t ms_trigger_counter;
#endif

	/* Mark-and-sweep recursion control: too deep recursion causes
	 * multi-pass processing to avoid growing C stack without bound.
	 */
	duk_uint_t ms_recursion_depth;

	/* Mark-and-sweep flags automatically active (used for critical sections). */
	duk_small_uint_t ms_base_flags;

	/* Mark-and-sweep running flag.  Prevents re-entry, and also causes
	 * refzero events to be ignored (= objects won't be queued to refzero_list).
	 *
	 * 0: mark-and-sweep not running
	 * 1: mark-and-sweep is running
	 * 2: heap destruction active or debugger active, prevent mark-and-sweep
	 *    and refzero processing (but mark-and-sweep not itself running)
	 */
	duk_uint_t ms_running;

	/* Mark-and-sweep prevent count, stacking.  Used to avoid M&S side
	 * effects (besides finalizers which are controlled separately) such
	 * as compacting the string table or object property tables.  This
	 * is also bumped when ms_running is set to prevent recursive re-entry.
	 * Can also be bumped when mark-and-sweep is not running.
	 */
	duk_uint_t ms_prevent_count;

	/* Finalizer processing prevent count, stacking.  Bumped when finalizers
	 * are processed to prevent recursive finalizer processing (first call site
	 * processing finalizers handles all finalizers until the list is empty).
	 * Can also be bumped explicitly to prevent finalizer execution.
	 */
	duk_uint_t pf_prevent_count;

	/* When processing finalize_list, don't actually run finalizers but
	 * queue finalizable objects back to heap_allocated as is.  This is
	 * used during heap destruction to deal with finalizers that keep
	 * on creating more finalizable garbage.
	 */
	duk_uint_t pf_skip_finalizers;

#if defined(DUK_USE_ASSERTIONS)
	/* Set when we're in a critical path where an error throw would cause
	 * e.g. sandboxing/protected call violations or state corruption.  This
	 * is just used for asserts.
	 */
	duk_bool_t error_not_allowed;
#endif

#if defined(DUK_USE_ASSERTIONS)
	/* Set when heap is still being initialized, helps with writing
	 * some assertions.
	 */
	duk_bool_t heap_initializing;
#endif

	/* Marker for detecting internal "double faults", errors thrown when
	 * we're trying to create an error object, see duk_error_throw.c.
	 */
	duk_bool_t creating_error;

	/* Marker for indicating we're calling a user error augmentation
	 * (errCreate/errThrow) function.  Errors created/thrown during
	 * such a call are not augmented.
	 */
#if defined(DUK_USE_AUGMENT_ERROR_THROW) || defined(DUK_USE_AUGMENT_ERROR_CREATE)
	duk_bool_t augmenting_error;
#endif

	/* Longjmp state. */
	duk_ljstate lj;

	/* Heap thread, used internally and for finalization. */
	duk_hthread *heap_thread;

	/* Current running thread. */
	duk_hthread *curr_thread;

	/* Heap level "stash" object (e.g., various reachability roots). */
	duk_hobject *heap_object;

	/* duk_handle_call / duk_handle_safe_call recursion depth limiting */
	duk_int_t call_recursion_depth;
	duk_int_t call_recursion_limit;

	/* Mix-in value for computing string hashes; should be reasonably unpredictable. */
	duk_uint32_t hash_seed;

	/* Random number state for duk_util_tinyrandom.c. */
#if !defined(DUK_USE_GET_RANDOM_DOUBLE)
#if defined(DUK_USE_PREFER_SIZE) || !defined(DUK_USE_64BIT_OPS)
	duk_uint32_t rnd_state;  /* State for Shamir's three-op algorithm */
#else
	duk_uint64_t rnd_state[2];  /* State for xoroshiro128+ */
#endif
#endif

	/* Counter for unique local symbol creation. */
	/* XXX: When 64-bit types are available, it would be more efficient to
	 * use a duk_uint64_t at least for incrementing but maybe also for
	 * string formatting in the Symbol constructor.
	 */
	duk_uint32_t sym_counter[2];

	/* For manual debugging: instruction count based on executor and
	 * interrupt counter book-keeping.  Inspect debug logs to see how
	 * they match up.
	 */
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
	duk_int_t inst_count_exec;
	duk_int_t inst_count_interrupt;
#endif

	/* Debugger state. */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	/* Callbacks and udata; dbg_read_cb != NULL is used to indicate attached state. */
	duk_debug_read_function dbg_read_cb;                /* required, NULL implies detached */
	duk_debug_write_function dbg_write_cb;              /* required */
	duk_debug_peek_function dbg_peek_cb;
	duk_debug_read_flush_function dbg_read_flush_cb;
	duk_debug_write_flush_function dbg_write_flush_cb;
	duk_debug_request_function dbg_request_cb;
	duk_debug_detached_function dbg_detached_cb;
	void *dbg_udata;

	/* The following are only relevant when debugger is attached. */
	duk_bool_t dbg_processing;              /* currently processing messages or breakpoints: don't enter message processing recursively (e.g. no breakpoints when processing debugger eval) */
	duk_bool_t dbg_state_dirty;             /* resend state next time executor is about to run */
	duk_bool_t dbg_force_restart;           /* force executor restart to recheck breakpoints; used to handle function returns (see GH-303) */
	duk_bool_t dbg_detaching;               /* debugger detaching; used to avoid calling detach handler recursively */
	duk_small_uint_t dbg_pause_flags;       /* flags for automatic pause behavior */
	duk_activation *dbg_pause_act;          /* activation related to pause behavior (pause on line change, function entry/exit) */
	duk_uint32_t dbg_pause_startline;       /* starting line number for line change related pause behavior */
	duk_breakpoint dbg_breakpoints[DUK_HEAP_MAX_BREAKPOINTS];  /* breakpoints: [0,breakpoint_count[ gc reachable */
	duk_small_uint_t dbg_breakpoint_count;
	duk_breakpoint *dbg_breakpoints_active[DUK_HEAP_MAX_BREAKPOINTS + 1];  /* currently active breakpoints: NULL term, borrowed pointers */
	/* XXX: make active breakpoints actual copies instead of pointers? */

	/* These are for rate limiting Status notifications and transport peeking. */
	duk_uint_t dbg_exec_counter;            /* cumulative opcode execution count (overflows are OK) */
	duk_uint_t dbg_last_counter;            /* value of dbg_exec_counter when we last did a Date-based check */
	duk_double_t dbg_last_time;             /* time when status/peek was last done (Date-based rate limit) */

	/* Used to support single-byte stream lookahead. */
	duk_bool_t dbg_have_next_byte;
	duk_uint8_t dbg_next_byte;
#endif  /* DUK_USE_DEBUGGER_SUPPORT */
#if defined(DUK_USE_ASSERTIONS)
	duk_bool_t dbg_calling_transport;       /* transport call in progress, calling into Duktape forbidden */
#endif

	/* String intern table (weak refs). */
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *strtable16;
#else
	duk_hstring **strtable;
#endif
	duk_uint32_t st_mask;    /* mask for lookup, st_size - 1 */
	duk_uint32_t st_size;    /* stringtable size */
#if (DUK_USE_STRTAB_MINSIZE != DUK_USE_STRTAB_MAXSIZE)
	duk_uint32_t st_count;   /* string count for resize load factor checks */
#endif
	duk_bool_t st_resizing;  /* string table is being resized; avoid recursive resize */

	/* String access cache (codepoint offset -> byte offset) for fast string
	 * character looping; 'weak' reference which needs special handling in GC.
	 */
	duk_strcache_entry strcache[DUK_HEAP_STRCACHE_SIZE];

#if defined(DUK_USE_LITCACHE_SIZE)
	/* Literal intern cache.  When enabled, strings interned as literals
	 * (e.g. duk_push_literal()) will be pinned and cached for the lifetime
	 * of the heap.
	 */
	duk_litcache_entry litcache[DUK_USE_LITCACHE_SIZE];
#endif

	/* Built-in strings. */
#if defined(DUK_USE_ROM_STRINGS)
	/* No field needed when strings are in ROM. */
#else
#if defined(DUK_USE_HEAPPTR16)
	duk_uint16_t strs16[DUK_HEAP_NUM_STRINGS];
#else
	duk_hstring *strs[DUK_HEAP_NUM_STRINGS];
#endif
#endif

	/* Stats. */
#if defined(DUK_USE_DEBUG)
	duk_int_t stats_exec_opcodes;
	duk_int_t stats_exec_interrupt;
	duk_int_t stats_exec_throw;
	duk_int_t stats_call_all;
	duk_int_t stats_call_tailcall;
	duk_int_t stats_call_ecmatoecma;
	duk_int_t stats_safecall_all;
	duk_int_t stats_safecall_nothrow;
	duk_int_t stats_safecall_throw;
	duk_int_t stats_ms_try_count;
	duk_int_t stats_ms_skip_count;
	duk_int_t stats_ms_emergency_count;
	duk_int_t stats_strtab_intern_hit;
	duk_int_t stats_strtab_intern_miss;
	duk_int_t stats_strtab_resize_check;
	duk_int_t stats_strtab_resize_grow;
	duk_int_t stats_strtab_resize_shrink;
	duk_int_t stats_strtab_litcache_hit;
	duk_int_t stats_strtab_litcache_miss;
	duk_int_t stats_strtab_litcache_pin;
	duk_int_t stats_object_realloc_props;
	duk_int_t stats_object_abandon_array;
	duk_int_t stats_getownpropdesc_count;
	duk_int_t stats_getownpropdesc_hit;
	duk_int_t stats_getownpropdesc_miss;
	duk_int_t stats_getpropdesc_count;
	duk_int_t stats_getpropdesc_hit;
	duk_int_t stats_getpropdesc_miss;
	duk_int_t stats_getprop_all;
	duk_int_t stats_getprop_arrayidx;
	duk_int_t stats_getprop_bufobjidx;
	duk_int_t stats_getprop_bufferidx;
	duk_int_t stats_getprop_bufferlen;
	duk_int_t stats_getprop_stringidx;
	duk_int_t stats_getprop_stringlen;
	duk_int_t stats_getprop_proxy;
	duk_int_t stats_getprop_arguments;
	duk_int_t stats_putprop_all;
	duk_int_t stats_putprop_arrayidx;
	duk_int_t stats_putprop_bufobjidx;
	duk_int_t stats_putprop_bufferidx;
	duk_int_t stats_putprop_proxy;
	duk_int_t stats_getvar_all;
	duk_int_t stats_putvar_all;
	duk_int_t stats_envrec_delayedcreate;
	duk_int_t stats_envrec_create;
	duk_int_t stats_envrec_newenv;
	duk_int_t stats_envrec_oldenv;
	duk_int_t stats_envrec_pushclosure;
#endif
};

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL
duk_heap *duk_heap_alloc(duk_alloc_function alloc_func,
                         duk_realloc_function realloc_func,
                         duk_free_function free_func,
                         void *heap_udata,
                         duk_fatal_function fatal_func);
DUK_INTERNAL_DECL void duk_heap_free(duk_heap *heap);
DUK_INTERNAL_DECL void duk_free_hobject(duk_heap *heap, duk_hobject *h);
DUK_INTERNAL_DECL void duk_free_hbuffer(duk_heap *heap, duk_hbuffer *h);
DUK_INTERNAL_DECL void duk_free_hstring(duk_heap *heap, duk_hstring *h);
DUK_INTERNAL_DECL void duk_heap_free_heaphdr_raw(duk_heap *heap, duk_heaphdr *hdr);

DUK_INTERNAL_DECL void duk_heap_insert_into_heap_allocated(duk_heap *heap, duk_heaphdr *hdr);
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_INTERNAL_DECL void duk_heap_remove_from_heap_allocated(duk_heap *heap, duk_heaphdr *hdr);
#endif
#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL_DECL void duk_heap_insert_into_finalize_list(duk_heap *heap, duk_heaphdr *hdr);
DUK_INTERNAL_DECL void duk_heap_remove_from_finalize_list(duk_heap *heap, duk_heaphdr *hdr);
#endif
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL duk_bool_t duk_heap_in_heap_allocated(duk_heap *heap, duk_heaphdr *ptr);
#endif
#if defined(DUK_USE_INTERRUPT_COUNTER)
DUK_INTERNAL_DECL void duk_heap_switch_thread(duk_heap *heap, duk_hthread *new_thr);
#endif

DUK_INTERNAL_DECL duk_hstring *duk_heap_strtable_intern(duk_heap *heap, const duk_uint8_t *str, duk_uint32_t blen);
DUK_INTERNAL_DECL duk_hstring *duk_heap_strtable_intern_checked(duk_hthread *thr, const duk_uint8_t *str, duk_uint32_t len);
#if defined(DUK_USE_LITCACHE_SIZE)
DUK_INTERNAL_DECL duk_hstring *duk_heap_strtable_intern_literal_checked(duk_hthread *thr, const duk_uint8_t *str, duk_uint32_t blen);
#endif
DUK_INTERNAL_DECL duk_hstring *duk_heap_strtable_intern_u32(duk_heap *heap, duk_uint32_t val);
DUK_INTERNAL_DECL duk_hstring *duk_heap_strtable_intern_u32_checked(duk_hthread *thr, duk_uint32_t val);
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_INTERNAL_DECL void duk_heap_strtable_unlink(duk_heap *heap, duk_hstring *h);
#endif
DUK_INTERNAL_DECL void duk_heap_strtable_unlink_prev(duk_heap *heap, duk_hstring *h, duk_hstring *prev);
DUK_INTERNAL_DECL void duk_heap_strtable_force_resize(duk_heap *heap);
DUK_INTERNAL void duk_heap_strtable_free(duk_heap *heap);
#if defined(DUK_USE_DEBUG)
DUK_INTERNAL void duk_heap_strtable_dump(duk_heap *heap);
#endif

DUK_INTERNAL_DECL void duk_heap_strcache_string_remove(duk_heap *heap, duk_hstring *h);
DUK_INTERNAL_DECL duk_uint_fast32_t duk_heap_strcache_offset_char2byte(duk_hthread *thr, duk_hstring *h, duk_uint_fast32_t char_offset);

#if defined(DUK_USE_PROVIDE_DEFAULT_ALLOC_FUNCTIONS)
DUK_INTERNAL_DECL void *duk_default_alloc_function(void *udata, duk_size_t size);
DUK_INTERNAL_DECL void *duk_default_realloc_function(void *udata, void *ptr, duk_size_t newsize);
DUK_INTERNAL_DECL void duk_default_free_function(void *udata, void *ptr);
#endif

DUK_INTERNAL_DECL void *duk_heap_mem_alloc(duk_heap *heap, duk_size_t size);
DUK_INTERNAL_DECL void *duk_heap_mem_alloc_zeroed(duk_heap *heap, duk_size_t size);
DUK_INTERNAL_DECL void *duk_heap_mem_alloc_checked(duk_hthread *thr, duk_size_t size);
DUK_INTERNAL_DECL void *duk_heap_mem_alloc_checked_zeroed(duk_hthread *thr, duk_size_t size);
DUK_INTERNAL_DECL void *duk_heap_mem_realloc(duk_heap *heap, void *ptr, duk_size_t newsize);
DUK_INTERNAL_DECL void *duk_heap_mem_realloc_indirect(duk_heap *heap, duk_mem_getptr cb, void *ud, duk_size_t newsize);
DUK_INTERNAL_DECL void duk_heap_mem_free(duk_heap *heap, void *ptr);

DUK_INTERNAL_DECL void duk_heap_free_freelists(duk_heap *heap);

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL_DECL void duk_heap_run_finalizer(duk_heap *heap, duk_hobject *obj);
DUK_INTERNAL_DECL void duk_heap_process_finalize_list(duk_heap *heap);
#endif  /* DUK_USE_FINALIZER_SUPPORT */

DUK_INTERNAL_DECL void duk_heap_mark_and_sweep(duk_heap *heap, duk_small_uint_t flags);

DUK_INTERNAL_DECL duk_uint32_t duk_heap_hashstring(duk_heap *heap, const duk_uint8_t *str, duk_size_t len);

#endif  /* DUK_HEAP_H_INCLUDED */
/* #include duk_debugger.h */
#if !defined(DUK_DEBUGGER_H_INCLUDED)
#define DUK_DEBUGGER_H_INCLUDED

/* Debugger protocol version is defined in the public API header. */

/* Initial bytes for markers. */
#define DUK_DBG_IB_EOM                   0x00
#define DUK_DBG_IB_REQUEST               0x01
#define DUK_DBG_IB_REPLY                 0x02
#define DUK_DBG_IB_ERROR                 0x03
#define DUK_DBG_IB_NOTIFY                0x04

/* Other initial bytes. */
#define DUK_DBG_IB_INT4                  0x10
#define DUK_DBG_IB_STR4                  0x11
#define DUK_DBG_IB_STR2                  0x12
#define DUK_DBG_IB_BUF4                  0x13
#define DUK_DBG_IB_BUF2                  0x14
#define DUK_DBG_IB_UNUSED                0x15
#define DUK_DBG_IB_UNDEFINED             0x16
#define DUK_DBG_IB_NULL                  0x17
#define DUK_DBG_IB_TRUE                  0x18
#define DUK_DBG_IB_FALSE                 0x19
#define DUK_DBG_IB_NUMBER                0x1a
#define DUK_DBG_IB_OBJECT                0x1b
#define DUK_DBG_IB_POINTER               0x1c
#define DUK_DBG_IB_LIGHTFUNC             0x1d
#define DUK_DBG_IB_HEAPPTR               0x1e
/* The short string/integer initial bytes starting from 0x60 don't have
 * defines now.
 */

/* Error codes. */
#define DUK_DBG_ERR_UNKNOWN              0x00
#define DUK_DBG_ERR_UNSUPPORTED          0x01
#define DUK_DBG_ERR_TOOMANY              0x02
#define DUK_DBG_ERR_NOTFOUND             0x03
#define DUK_DBG_ERR_APPLICATION          0x04

/* Commands and notifys initiated by Duktape. */
#define DUK_DBG_CMD_STATUS               0x01
#define DUK_DBG_CMD_UNUSED_2             0x02  /* Duktape 1.x: print notify */
#define DUK_DBG_CMD_UNUSED_3             0x03  /* Duktape 1.x: alert notify */
#define DUK_DBG_CMD_UNUSED_4             0x04  /* Duktape 1.x: log notify */
#define DUK_DBG_CMD_THROW                0x05
#define DUK_DBG_CMD_DETACHING            0x06
#define DUK_DBG_CMD_APPNOTIFY            0x07

/* Commands initiated by debug client. */
#define DUK_DBG_CMD_BASICINFO            0x10
#define DUK_DBG_CMD_TRIGGERSTATUS        0x11
#define DUK_DBG_CMD_PAUSE                0x12
#define DUK_DBG_CMD_RESUME               0x13
#define DUK_DBG_CMD_STEPINTO             0x14
#define DUK_DBG_CMD_STEPOVER             0x15
#define DUK_DBG_CMD_STEPOUT              0x16
#define DUK_DBG_CMD_LISTBREAK            0x17
#define DUK_DBG_CMD_ADDBREAK             0x18
#define DUK_DBG_CMD_DELBREAK             0x19
#define DUK_DBG_CMD_GETVAR               0x1a
#define DUK_DBG_CMD_PUTVAR               0x1b
#define DUK_DBG_CMD_GETCALLSTACK         0x1c
#define DUK_DBG_CMD_GETLOCALS            0x1d
#define DUK_DBG_CMD_EVAL                 0x1e
#define DUK_DBG_CMD_DETACH               0x1f
#define DUK_DBG_CMD_DUMPHEAP             0x20
#define DUK_DBG_CMD_GETBYTECODE          0x21
#define DUK_DBG_CMD_APPREQUEST           0x22
#define DUK_DBG_CMD_GETHEAPOBJINFO       0x23
#define DUK_DBG_CMD_GETOBJPROPDESC       0x24
#define DUK_DBG_CMD_GETOBJPROPDESCRANGE  0x25

/* The low 8 bits map directly to duk_hobject.h DUK_PROPDESC_FLAG_xxx.
 * The remaining flags are specific to the debugger.
 */
#define DUK_DBG_PROPFLAG_SYMBOL          (1U << 8)
#define DUK_DBG_PROPFLAG_HIDDEN          (1U << 9)

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL_DECL void duk_debug_do_detach(duk_heap *heap);

DUK_INTERNAL_DECL duk_bool_t duk_debug_read_peek(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_debug_write_flush(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_debug_skip_bytes(duk_hthread *thr, duk_size_t length);
DUK_INTERNAL_DECL void duk_debug_skip_byte(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_debug_read_bytes(duk_hthread *thr, duk_uint8_t *data, duk_size_t length);
DUK_INTERNAL_DECL duk_uint8_t duk_debug_read_byte(duk_hthread *thr);
DUK_INTERNAL_DECL duk_int32_t duk_debug_read_int(duk_hthread *thr);
DUK_INTERNAL_DECL duk_hstring *duk_debug_read_hstring(duk_hthread *thr);
/* XXX: exposed duk_debug_read_pointer */
/* XXX: exposed duk_debug_read_buffer */
/* XXX: exposed duk_debug_read_hbuffer */
#if 0
DUK_INTERNAL_DECL duk_heaphdr *duk_debug_read_heapptr(duk_hthread *thr);
#endif
#if defined(DUK_USE_DEBUGGER_INSPECT)
DUK_INTERNAL_DECL duk_heaphdr *duk_debug_read_any_ptr(duk_hthread *thr);
#endif
DUK_INTERNAL_DECL duk_tval *duk_debug_read_tval(duk_hthread *thr);

DUK_INTERNAL_DECL void duk_debug_write_bytes(duk_hthread *thr, const duk_uint8_t *data, duk_size_t length);
DUK_INTERNAL_DECL void duk_debug_write_byte(duk_hthread *thr, duk_uint8_t x);
DUK_INTERNAL_DECL void duk_debug_write_unused(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_debug_write_undefined(duk_hthread *thr);
#if defined(DUK_USE_DEBUGGER_INSPECT)
DUK_INTERNAL_DECL void duk_debug_write_null(duk_hthread *thr);
#endif
DUK_INTERNAL_DECL void duk_debug_write_boolean(duk_hthread *thr, duk_uint_t val);
DUK_INTERNAL_DECL void duk_debug_write_int(duk_hthread *thr, duk_int32_t x);
DUK_INTERNAL_DECL void duk_debug_write_uint(duk_hthread *thr, duk_uint32_t x);
DUK_INTERNAL_DECL void duk_debug_write_string(duk_hthread *thr, const char *data, duk_size_t length);
DUK_INTERNAL_DECL void duk_debug_write_cstring(duk_hthread *thr, const char *data);
DUK_INTERNAL_DECL void duk_debug_write_hstring(duk_hthread *thr, duk_hstring *h);
DUK_INTERNAL_DECL void duk_debug_write_buffer(duk_hthread *thr, const char *data, duk_size_t length);
DUK_INTERNAL_DECL void duk_debug_write_hbuffer(duk_hthread *thr, duk_hbuffer *h);
DUK_INTERNAL_DECL void duk_debug_write_pointer(duk_hthread *thr, void *ptr);
#if defined(DUK_USE_DEBUGGER_DUMPHEAP) || defined(DUK_USE_DEBUGGER_INSPECT)
DUK_INTERNAL_DECL void duk_debug_write_heapptr(duk_hthread *thr, duk_heaphdr *h);
#endif
DUK_INTERNAL_DECL void duk_debug_write_hobject(duk_hthread *thr, duk_hobject *obj);
DUK_INTERNAL_DECL void duk_debug_write_tval(duk_hthread *thr, duk_tval *tv);
#if 0  /* unused */
DUK_INTERNAL_DECL void duk_debug_write_request(duk_hthread *thr, duk_small_uint_t command);
#endif
DUK_INTERNAL_DECL void duk_debug_write_reply(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_debug_write_error_eom(duk_hthread *thr, duk_small_uint_t err_code, const char *msg);
DUK_INTERNAL_DECL void duk_debug_write_notify(duk_hthread *thr, duk_small_uint_t command);
DUK_INTERNAL_DECL void duk_debug_write_eom(duk_hthread *thr);

DUK_INTERNAL_DECL duk_uint_fast32_t duk_debug_curr_line(duk_hthread *thr);
DUK_INTERNAL_DECL void duk_debug_send_status(duk_hthread *thr);
#if defined(DUK_USE_DEBUGGER_THROW_NOTIFY)
DUK_INTERNAL_DECL void duk_debug_send_throw(duk_hthread *thr, duk_bool_t fatal);
#endif

DUK_INTERNAL_DECL void duk_debug_halt_execution(duk_hthread *thr, duk_bool_t use_prev_pc);
DUK_INTERNAL_DECL duk_bool_t duk_debug_process_messages(duk_hthread *thr, duk_bool_t no_block);

DUK_INTERNAL_DECL duk_small_int_t duk_debug_add_breakpoint(duk_hthread *thr, duk_hstring *filename, duk_uint32_t line);
DUK_INTERNAL_DECL duk_bool_t duk_debug_remove_breakpoint(duk_hthread *thr, duk_small_uint_t breakpoint_index);

DUK_INTERNAL_DECL duk_bool_t duk_debug_is_attached(duk_heap *heap);
DUK_INTERNAL_DECL duk_bool_t duk_debug_is_paused(duk_heap *heap);
DUK_INTERNAL_DECL void duk_debug_set_paused(duk_heap *heap);
DUK_INTERNAL_DECL void duk_debug_clear_paused(duk_heap *heap);
DUK_INTERNAL_DECL void duk_debug_clear_pause_state(duk_heap *heap);
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

#endif  /* DUK_DEBUGGER_H_INCLUDED */
/* #include duk_debug.h */
/*
 *  Debugging macros, DUK_DPRINT() and its variants in particular.
 *
 *  DUK_DPRINT() allows formatted debug prints, and supports standard
 *  and Duktape specific formatters.  See duk_debug_vsnprintf.c for details.
 *
 *  DUK_D(x), DUK_DD(x), and DUK_DDD(x) are used together with log macros
 *  for technical reasons.  They are concretely used to hide 'x' from the
 *  compiler when the corresponding log level is disabled.  This allows
 *  clean builds on non-C99 compilers, at the cost of more verbose code.
 *  Examples:
 *
 *    DUK_D(DUK_DPRINT("foo"));
 *    DUK_DD(DUK_DDPRINT("foo"));
 *    DUK_DDD(DUK_DDDPRINT("foo"));
 *
 *  This approach is preferable to the old "double parentheses" hack because
 *  double parentheses make the C99 solution worse: __FILE__ and __LINE__ can
 *  no longer be added transparently without going through globals, which
 *  works poorly with threading.
 */

#if !defined(DUK_DEBUG_H_INCLUDED)
#define DUK_DEBUG_H_INCLUDED

#if defined(DUK_USE_DEBUG)

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 0)
#define DUK_D(x) x
#else
#define DUK_D(x) do { } while (0) /* omit */
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 1)
#define DUK_DD(x) x
#else
#define DUK_DD(x) do { } while (0) /* omit */
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
#define DUK_DDD(x) x
#else
#define DUK_DDD(x) do { } while (0) /* omit */
#endif

/*
 *  Exposed debug macros: debugging enabled
 */

#if defined(DUK_USE_VARIADIC_MACROS)

/* Note: combining __FILE__, __LINE__, and __func__ into fmt would be
 * possible compile time, but waste some space with shared function names.
 */
#define DUK__DEBUG_LOG(lev,...)  duk_debug_log((duk_int_t) (lev), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, DUK_FUNC_MACRO, __VA_ARGS__);

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 0)
#define DUK_DPRINT(...)          DUK__DEBUG_LOG(DUK_LEVEL_DEBUG, __VA_ARGS__)
#else
#define DUK_DPRINT(...)
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 1)
#define DUK_DDPRINT(...)         DUK__DEBUG_LOG(DUK_LEVEL_DDEBUG, __VA_ARGS__)
#else
#define DUK_DDPRINT(...)
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
#define DUK_DDDPRINT(...)        DUK__DEBUG_LOG(DUK_LEVEL_DDDEBUG, __VA_ARGS__)
#else
#define DUK_DDDPRINT(...)
#endif

#else  /* DUK_USE_VARIADIC_MACROS */

#define DUK__DEBUG_STASH(lev)    \
	(void) DUK_SNPRINTF(duk_debug_file_stash, DUK_DEBUG_STASH_SIZE, "%s", (const char *) DUK_FILE_MACRO), \
	(void) (duk_debug_file_stash[DUK_DEBUG_STASH_SIZE - 1] = (char) 0), \
	(void) (duk_debug_line_stash = (duk_int_t) DUK_LINE_MACRO), \
	(void) DUK_SNPRINTF(duk_debug_func_stash, DUK_DEBUG_STASH_SIZE, "%s", (const char *) DUK_FUNC_MACRO), \
	(void) (duk_debug_func_stash[DUK_DEBUG_STASH_SIZE - 1] = (char) 0), \
	(void) (duk_debug_level_stash = (lev))

/* Without variadic macros resort to comma expression trickery to handle debug
 * prints.  This generates a lot of harmless warnings.  These hacks are not
 * needed normally because DUK_D() and friends will hide the entire debug log
 * statement from the compiler.
 */

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 0)
#define DUK_DPRINT  DUK__DEBUG_STASH(DUK_LEVEL_DEBUG), (void) duk_debug_log  /* args go here in parens */
#else
#define DUK_DPRINT  0 && /* args go here as a comma expression in parens */
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 1)
#define DUK_DDPRINT  DUK__DEBUG_STASH(DUK_LEVEL_DDEBUG), (void) duk_debug_log  /* args go here in parens */
#else
#define DUK_DDPRINT  0 && /* args */
#endif

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
#define DUK_DDDPRINT  DUK__DEBUG_STASH(DUK_LEVEL_DDDEBUG), (void) duk_debug_log  /* args go here in parens */
#else
#define DUK_DDDPRINT  0 && /* args */
#endif

#endif  /* DUK_USE_VARIADIC_MACROS */

#else  /* DUK_USE_DEBUG */

/*
 *  Exposed debug macros: debugging disabled
 */

#define DUK_D(x) do { } while (0) /* omit */
#define DUK_DD(x) do { } while (0) /* omit */
#define DUK_DDD(x) do { } while (0) /* omit */

#if defined(DUK_USE_VARIADIC_MACROS)

#define DUK_DPRINT(...)
#define DUK_DDPRINT(...)
#define DUK_DDDPRINT(...)

#else  /* DUK_USE_VARIADIC_MACROS */

#define DUK_DPRINT    0 && /* args go here as a comma expression in parens */
#define DUK_DDPRINT   0 && /* args */
#define DUK_DDDPRINT  0 && /* args */

#endif  /* DUK_USE_VARIADIC_MACROS */

#endif  /* DUK_USE_DEBUG */

/*
 *  Structs
 */

#if defined(DUK_USE_DEBUG)
struct duk_fixedbuffer {
	duk_uint8_t *buffer;
	duk_size_t length;
	duk_size_t offset;
	duk_bool_t truncated;
};
#endif

/*
 *  Prototypes
 */

#if defined(DUK_USE_DEBUG)
DUK_INTERNAL_DECL duk_int_t duk_debug_vsnprintf(char *str, duk_size_t size, const char *format, va_list ap);
#if 0  /*unused*/
DUK_INTERNAL_DECL duk_int_t duk_debug_snprintf(char *str, duk_size_t size, const char *format, ...);
#endif
DUK_INTERNAL_DECL void duk_debug_format_funcptr(char *buf, duk_size_t buf_size, duk_uint8_t *fptr, duk_size_t fptr_size);

#if defined(DUK_USE_VARIADIC_MACROS)
DUK_INTERNAL_DECL void duk_debug_log(duk_int_t level, const char *file, duk_int_t line, const char *func, const char *fmt, ...);
#else  /* DUK_USE_VARIADIC_MACROS */
/* parameter passing, not thread safe */
#define DUK_DEBUG_STASH_SIZE  128
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL char duk_debug_file_stash[DUK_DEBUG_STASH_SIZE];
DUK_INTERNAL_DECL duk_int_t duk_debug_line_stash;
DUK_INTERNAL_DECL char duk_debug_func_stash[DUK_DEBUG_STASH_SIZE];
DUK_INTERNAL_DECL duk_int_t duk_debug_level_stash;
#endif
DUK_INTERNAL_DECL void duk_debug_log(const char *fmt, ...);
#endif  /* DUK_USE_VARIADIC_MACROS */

DUK_INTERNAL_DECL void duk_fb_put_bytes(duk_fixedbuffer *fb, const duk_uint8_t *buffer, duk_size_t length);
DUK_INTERNAL_DECL void duk_fb_put_byte(duk_fixedbuffer *fb, duk_uint8_t x);
DUK_INTERNAL_DECL void duk_fb_put_cstring(duk_fixedbuffer *fb, const char *x);
DUK_INTERNAL_DECL void duk_fb_sprintf(duk_fixedbuffer *fb, const char *fmt, ...);
DUK_INTERNAL_DECL void duk_fb_put_funcptr(duk_fixedbuffer *fb, duk_uint8_t *fptr, duk_size_t fptr_size);
DUK_INTERNAL_DECL duk_bool_t duk_fb_is_full(duk_fixedbuffer *fb);

#endif  /* DUK_USE_DEBUG */

#endif  /* DUK_DEBUG_H_INCLUDED */
/* #include duk_error.h */
/*
 *  Error handling macros, assertion macro, error codes.
 *
 *  There are three types of 'errors':
 *
 *    1. Ordinary errors relative to a thread, cause a longjmp, catchable.
 *    2. Fatal errors relative to a heap, cause fatal handler to be called.
 *    3. Fatal errors without context, cause the default (not heap specific)
 *       fatal handler to be called.
 *
 *  Fatal errors without context are used by debug code such as assertions.
 *  By providing a fatal error handler for a Duktape heap, user code can
 *  avoid fatal errors without context in non-debug builds.
 */

#if !defined(DUK_ERROR_H_INCLUDED)
#define DUK_ERROR_H_INCLUDED

/*
 *  Error codes: defined in duktape.h
 *
 *  Error codes are used as a shorthand to throw exceptions from inside
 *  the implementation.  The appropriate ECMAScript object is constructed
 *  based on the code.  ECMAScript code throws objects directly.  The error
 *  codes are defined in the public API header because they are also used
 *  by calling code.
 */

/*
 *  Normal error
 *
 *  Normal error is thrown with a longjmp() through the current setjmp()
 *  catchpoint record in the duk_heap.  The 'curr_thread' of the duk_heap
 *  identifies the throwing thread.
 *
 *  Error formatting is usually unnecessary.  The error macros provide a
 *  zero argument version (no formatting) and separate macros for small
 *  argument counts.  Variadic macros are not used to avoid portability
 *  issues and avoid the need for stash-based workarounds when they're not
 *  available.  Vararg calls are avoided for non-formatted error calls
 *  because vararg call sites are larger than normal, and there are a lot
 *  of call sites with no formatting.
 *
 *  Note that special formatting provided by debug macros is NOT available.
 *
 *  The _RAW variants allow the caller to specify file and line.  This makes
 *  it easier to write checked calls which want to use the call site of the
 *  checked function, not the error macro call inside the checked function.
 */

#if defined(DUK_USE_VERBOSE_ERRORS)

/* Because there are quite many call sites, pack error code (require at most
 * 8-bit) into a single argument.
 */
#define DUK_ERROR(thr,err,msg) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) DUK_LINE_MACRO; \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error((thr), DUK_FILE_MACRO, (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (msg)); \
	} while (0)
#define DUK_ERROR_RAW(thr,file,line,err,msg) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) (line); \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error((thr), (file), (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (msg)); \
	} while (0)

#define DUK_ERROR_FMT1(thr,err,fmt,arg1) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) DUK_LINE_MACRO; \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), DUK_FILE_MACRO, (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1)); \
	} while (0)
#define DUK_ERROR_RAW_FMT1(thr,file,line,err,fmt,arg1) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) (line); \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), (file), (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1)); \
	} while (0)

#define DUK_ERROR_FMT2(thr,err,fmt,arg1,arg2) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) DUK_LINE_MACRO; \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), DUK_FILE_MACRO, (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2)); \
	} while (0)
#define DUK_ERROR_RAW_FMT2(thr,file,line,err,fmt,arg1,arg2) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) (line); \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), (file), (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2)); \
	} while (0)

#define DUK_ERROR_FMT3(thr,err,fmt,arg1,arg2,arg3) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) DUK_LINE_MACRO; \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), DUK_FILE_MACRO, (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2), (arg3)); \
	} while (0)
#define DUK_ERROR_RAW_FMT3(thr,file,line,err,fmt,arg1,arg2,arg3) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) (line); \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), (file), (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2), (arg3)); \
	} while (0)

#define DUK_ERROR_FMT4(thr,err,fmt,arg1,arg2,arg3,arg4) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) DUK_LINE_MACRO; \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), DUK_FILE_MACRO, (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2), (arg3), (arg4)); \
	} while (0)
#define DUK_ERROR_RAW_FMT4(thr,file,line,err,fmt,arg1,arg2,arg3,arg4) do { \
		duk_errcode_t duk__err = (err); duk_int_t duk__line = (duk_int_t) (line); \
		DUK_ASSERT(duk__err >= 0 && duk__err <= 0xff); DUK_ASSERT(duk__line >= 0 && duk__line <= 0x00ffffffL); \
		duk_err_handle_error_fmt((thr), (file), (((duk_uint_t) duk__err) << 24) | ((duk_uint_t) duk__line), (fmt), (arg1), (arg2), (arg3), (arg4)); \
	} while (0)

#else  /* DUK_USE_VERBOSE_ERRORS */

#define DUK_ERROR(thr,err,msg)                    duk_err_handle_error((thr), (err))
#define DUK_ERROR_RAW(thr,file,line,err,msg)      duk_err_handle_error((thr), (err))

#define DUK_ERROR_FMT1(thr,err,fmt,arg1) DUK_ERROR((thr),(err),(fmt))
#define DUK_ERROR_RAW_FMT1(thr,file,line,err,fmt,arg1) DUK_ERROR_RAW((thr),(file),(line),(err),(fmt))

#define DUK_ERROR_FMT2(thr,err,fmt,arg1,arg2) DUK_ERROR((thr),(err),(fmt))
#define DUK_ERROR_RAW_FMT2(thr,file,line,err,fmt,arg1,arg2) DUK_ERROR_RAW((thr),(file),(line),(err),(fmt))

#define DUK_ERROR_FMT3(thr,err,fmt,arg1,arg2,arg3) DUK_ERROR((thr),(err),(fmt))
#define DUK_ERROR_RAW_FMT3(thr,file,line,err,fmt,arg1,arg2,arg3) DUK_ERROR_RAW((thr),(file),(line),(err),(fmt))

#define DUK_ERROR_FMT4(thr,err,fmt,arg1,arg2,arg3,arg4) DUK_ERROR((thr),(err),(fmt))
#define DUK_ERROR_RAW_FMT4(thr,file,line,err,fmt,arg1,arg2,arg3,arg4) DUK_ERROR_RAW((thr),(file),(line),(err),(fmt))

#endif  /* DUK_USE_VERBOSE_ERRORS */

/*
 *  Fatal error without context
 *
 *  The macro is an expression to make it compatible with DUK_ASSERT_EXPR().
 */

#define DUK_FATAL_WITHOUT_CONTEXT(msg) \
	duk_default_fatal_handler(NULL, (msg))

/*
 *  Error throwing helpers
 *
 *  The goal is to provide verbose and configurable error messages.  Call
 *  sites should be clean in source code and compile to a small footprint.
 *  Small footprint is also useful for performance because small cold paths
 *  reduce code cache pressure.  Adding macros here only makes sense if there
 *  are enough call sites to get concrete benefits.
 *
 *  DUK_ERROR_xxx() macros are generic and can be used anywhere.
 *
 *  DUK_DCERROR_xxx() macros can only be used in Duktape/C functions where
 *  the "return DUK_RET_xxx;" shorthand is available for low memory targets.
 *  The DUK_DCERROR_xxx() macros always either throw or perform a
 *  'return DUK_RET_xxx' from the calling function.
 */

#if defined(DUK_USE_VERBOSE_ERRORS)
/* Verbose errors with key/value summaries (non-paranoid) or without key/value
 * summaries (paranoid, for some security sensitive environments), the paranoid
 * vs. non-paranoid distinction affects only a few specific errors.
 */
#if defined(DUK_USE_PARANOID_ERRORS)
#define DUK_ERROR_REQUIRE_TYPE_INDEX(thr,idx,expectname,lowmemstr) do { \
		duk_err_require_type_index((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, (idx), (expectname)); \
	} while (0)
#else  /* DUK_USE_PARANOID_ERRORS */
#define DUK_ERROR_REQUIRE_TYPE_INDEX(thr,idx,expectname,lowmemstr) do { \
		duk_err_require_type_index((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, (idx), (expectname)); \
	} while (0)
#endif  /* DUK_USE_PARANOID_ERRORS */

#define DUK_ERROR_INTERNAL(thr) do { \
		duk_err_error_internal((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_DCERROR_INTERNAL(thr) do { \
		DUK_ERROR_INTERNAL((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_ALLOC_FAILED(thr) do { \
		duk_err_error_alloc_failed((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_ERROR_UNSUPPORTED(thr) do { \
		DUK_ERROR((thr), DUK_ERR_ERROR, DUK_STR_UNSUPPORTED); \
	} while (0)
#define DUK_DCERROR_UNSUPPORTED(thr) do { \
		DUK_ERROR_UNSUPPORTED((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_ERROR(thr,msg) do { \
		duk_err_error((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, (msg)); \
	} while (0)
#define DUK_ERROR_RANGE_INDEX(thr,idx) do { \
		duk_err_range_index((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, (idx)); \
	} while (0)
#define DUK_ERROR_RANGE_PUSH_BEYOND(thr) do { \
		duk_err_range_push_beyond((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_ARGS(thr) do { \
		DUK_ERROR_RANGE((thr), DUK_STR_INVALID_ARGS); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_ARGS(thr) do { \
		DUK_ERROR_RANGE_INVALID_ARGS((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_COUNT(thr) do { \
		DUK_ERROR_RANGE((thr), DUK_STR_INVALID_COUNT); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_COUNT(thr) do { \
		DUK_ERROR_RANGE_INVALID_COUNT((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_LENGTH(thr) do { \
		DUK_ERROR_RANGE((thr), DUK_STR_INVALID_LENGTH); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_LENGTH(thr) do { \
		DUK_ERROR_RANGE_INVALID_LENGTH((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_RANGE(thr,msg) do { \
		duk_err_range((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO, (msg)); \
	} while (0)
#define DUK_ERROR_EVAL(thr,msg) do { \
		DUK_ERROR((thr), DUK_ERR_EVAL_ERROR, (msg)); \
	} while (0)
#define DUK_ERROR_REFERENCE(thr,msg) do { \
		DUK_ERROR((thr), DUK_ERR_REFERENCE_ERROR, (msg)); \
	} while (0)
#define DUK_ERROR_SYNTAX(thr,msg) do { \
		DUK_ERROR((thr), DUK_ERR_SYNTAX_ERROR, (msg)); \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_ARGS(thr) do { \
		duk_err_type_invalid_args((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_ARGS(thr) do { \
		DUK_ERROR_TYPE_INVALID_ARGS((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_STATE(thr) do { \
		duk_err_type_invalid_state((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_STATE(thr) do { \
		DUK_ERROR_TYPE_INVALID_STATE((thr)); \
		return 0; \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr) do { \
		duk_err_type_invalid_trap_result((thr), DUK_FILE_MACRO, (duk_int_t) DUK_LINE_MACRO); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_TRAP_RESULT(thr) do { \
		DUK_ERROR_TYPE((thr), DUK_STR_INVALID_TRAP_RESULT); \
	} while (0)
#define DUK_ERROR_TYPE(thr,msg) do { \
		DUK_ERROR((thr), DUK_ERR_TYPE_ERROR, (msg)); \
	} while (0)
#define DUK_ERROR_URI(thr,msg) do { \
		DUK_ERROR((thr), DUK_ERR_URI_ERROR, (msg)); \
	} while (0)
#else  /* DUK_USE_VERBOSE_ERRORS */
/* Non-verbose errors for low memory targets: no file, line, or message. */

#define DUK_ERROR_REQUIRE_TYPE_INDEX(thr,idx,expectname,lowmemstr) do { \
		duk_err_type((thr)); \
	} while (0)

#define DUK_ERROR_INTERNAL(thr) do { \
		duk_err_error((thr)); \
	} while (0)
#define DUK_DCERROR_INTERNAL(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_ERROR; \
	} while (0)
#define DUK_ERROR_ALLOC_FAILED(thr) do { \
		duk_err_error((thr)); \
	} while (0)
#define DUK_ERROR_UNSUPPORTED(thr) do { \
		duk_err_error((thr)); \
	} while (0)
#define DUK_DCERROR_UNSUPPORTED(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_ERROR; \
	} while (0)
#define DUK_ERROR_ERROR(thr,msg) do { \
		duk_err_error((thr)); \
	} while (0)
#define DUK_ERROR_RANGE_INDEX(thr,idx) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_ERROR_RANGE_PUSH_BEYOND(thr) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_ARGS(thr) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_ARGS(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_RANGE_ERROR; \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_COUNT(thr) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_COUNT(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_RANGE_ERROR; \
	} while (0)
#define DUK_ERROR_RANGE_INVALID_LENGTH(thr) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_DCERROR_RANGE_INVALID_LENGTH(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_RANGE_ERROR; \
	} while (0)
#define DUK_ERROR_RANGE(thr,msg) do { \
		duk_err_range((thr)); \
	} while (0)
#define DUK_ERROR_EVAL(thr,msg) do { \
		duk_err_eval((thr)); \
	} while (0)
#define DUK_ERROR_REFERENCE(thr,msg) do { \
		duk_err_reference((thr)); \
	} while (0)
#define DUK_ERROR_SYNTAX(thr,msg) do { \
		duk_err_syntax((thr)); \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_ARGS(thr) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_ARGS(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_TYPE_ERROR; \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_STATE(thr) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_STATE(thr) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_DCERROR_TYPE_INVALID_TRAP_RESULT(thr) do { \
		DUK_UNREF((thr)); \
		return DUK_RET_TYPE_ERROR; \
	} while (0)
#define DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_ERROR_TYPE(thr,msg) do { \
		duk_err_type((thr)); \
	} while (0)
#define DUK_ERROR_URI(thr,msg) do { \
		duk_err_uri((thr)); \
	} while (0)
#endif  /* DUK_USE_VERBOSE_ERRORS */

/*
 *  Assert macro: failure causes a fatal error.
 *
 *  NOTE: since the assert macro doesn't take a heap/context argument, there's
 *  no way to look up a heap/context specific fatal error handler which may have
 *  been given by the application.  Instead, assertion failures always use the
 *  internal default fatal error handler; it can be replaced via duk_config.h
 *  and then applies to all Duktape heaps.
 */

#if defined(DUK_USE_ASSERTIONS)

/* The message should be a compile time constant without formatting (less risk);
 * we don't care about assertion text size because they're not used in production
 * builds.
 */
#define DUK_ASSERT(x)  do { \
	if (!(x)) { \
		DUK_FATAL_WITHOUT_CONTEXT("assertion failed: " #x \
			" (" DUK_FILE_MACRO ":" DUK_MACRO_STRINGIFY(DUK_LINE_MACRO) ")"); \
	} \
	} while (0)

/* Assertion compatible inside a comma expression, evaluates to void. */
#define DUK_ASSERT_EXPR(x) \
	((void) ((x) ? 0 : (DUK_FATAL_WITHOUT_CONTEXT("assertion failed: " #x \
				" (" DUK_FILE_MACRO ":" DUK_MACRO_STRINGIFY(DUK_LINE_MACRO) ")"), 0)))

#else  /* DUK_USE_ASSERTIONS */

#define DUK_ASSERT(x)  do { /* assertion omitted */ } while (0)

#define DUK_ASSERT_EXPR(x)  ((void) 0)

#endif  /* DUK_USE_ASSERTIONS */

/* this variant is used when an assert would generate a compile warning by
 * being always true (e.g. >= 0 comparison for an unsigned value
 */
#define DUK_ASSERT_DISABLE(x)  do { /* assertion disabled */ } while (0)

/*
 *  Assertion helpers
 */

#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_REFERENCE_COUNTING)
#define DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(h)  do { \
		DUK_ASSERT((h) == NULL || DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) (h)) > 0); \
	} while (0)
#define DUK_ASSERT_REFCOUNT_NONZERO_TVAL(tv)  do { \
		if ((tv) != NULL && DUK_TVAL_IS_HEAP_ALLOCATED((tv))) { \
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(DUK_TVAL_GET_HEAPHDR((tv))) > 0); \
		} \
	} while (0)
#else
#define DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(h)  /* no refcount check */
#define DUK_ASSERT_REFCOUNT_NONZERO_TVAL(tv)    /* no refcount check */
#endif

#define DUK_ASSERT_TOP(ctx,n)  DUK_ASSERT((duk_idx_t) duk_get_top((ctx)) == (duk_idx_t) (n))

#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_PACKED_TVAL)
#define DUK_ASSERT_DOUBLE_IS_NORMALIZED(dval)  do { \
		duk_double_union duk__assert_tmp_du; \
		duk__assert_tmp_du.d = (dval); \
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&duk__assert_tmp_du)); \
	} while (0)
#else
#define DUK_ASSERT_DOUBLE_IS_NORMALIZED(dval)  /* nop */
#endif

#define DUK_ASSERT_VS_SPACE(thr) \
	DUK_ASSERT(thr->valstack_top < thr->valstack_end)

/*
 *  Helper to initialize a memory area (e.g. struct) with garbage when
 *  assertions enabled.
 */

#if defined(DUK_USE_ASSERTIONS)
#define DUK_ASSERT_SET_GARBAGE(ptr,size) do { \
		duk_memset_unsafe((void *) (ptr), 0x5a, size); \
	} while (0)
#else
#define DUK_ASSERT_SET_GARBAGE(ptr,size) do {} while (0)
#endif

/*
 *  Helper for valstack space
 *
 *  Caller of DUK_ASSERT_VALSTACK_SPACE() estimates the number of free stack entries
 *  required for its own use, and any child calls which are not (a) Duktape API calls
 *  or (b) Duktape calls which involve extending the valstack (e.g. getter call).
 */

#define DUK_VALSTACK_ASSERT_EXTRA  5  /* this is added to checks to allow for Duktape
                                       * API calls in addition to function's own use
                                       */
#if defined(DUK_USE_ASSERTIONS)
#define DUK_ASSERT_VALSTACK_SPACE(thr,n)   do { \
		DUK_ASSERT((thr) != NULL); \
		DUK_ASSERT((thr)->valstack_end - (thr)->valstack_top >= (n) + DUK_VALSTACK_ASSERT_EXTRA); \
	} while (0)
#else
#define DUK_ASSERT_VALSTACK_SPACE(thr,n)   /* no valstack space check */
#endif

/*
 *  Prototypes
 */

#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_handle_error(duk_hthread *thr, const char *filename, duk_uint_t line_and_code, const char *msg));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_handle_error_fmt(duk_hthread *thr, const char *filename, duk_uint_t line_and_code, const char *fmt, ...));
#else  /* DUK_USE_VERBOSE_ERRORS */
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_handle_error(duk_hthread *thr, duk_errcode_t code));
#endif  /* DUK_USE_VERBOSE_ERRORS */

#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_create_and_throw(duk_hthread *thr, duk_errcode_t code, const char *msg, const char *filename, duk_int_t line));
#else
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_create_and_throw(duk_hthread *thr, duk_errcode_t code));
#endif

DUK_NORETURN(DUK_INTERNAL_DECL void duk_error_throw_from_negative_rc(duk_hthread *thr, duk_ret_t rc));

#define DUK_AUGMENT_FLAG_NOBLAME_FILELINE  (1U << 0)  /* if set, don't blame C file/line for .fileName and .lineNumber */
#define DUK_AUGMENT_FLAG_SKIP_ONE          (1U << 1)  /* if set, skip topmost activation in traceback construction */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_INTERNAL_DECL void duk_err_augment_error_create(duk_hthread *thr, duk_hthread *thr_callstack, const char *filename, duk_int_t line, duk_small_uint_t flags);
#endif
#if defined(DUK_USE_AUGMENT_ERROR_THROW)
DUK_INTERNAL_DECL void duk_err_augment_error_throw(duk_hthread *thr);
#endif

#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_require_type_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx, const char *expect_name));
#else
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_require_type_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx, const char *expect_name));
#endif
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_error_internal(duk_hthread *thr, const char *filename, duk_int_t linenumber));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_error_alloc_failed(duk_hthread *thr, const char *filename, duk_int_t linenumber));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_error(duk_hthread *thr, const char *filename, duk_int_t linenumber, const char *message));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_range_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_range_push_beyond(duk_hthread *thr, const char *filename, duk_int_t linenumber));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_range(duk_hthread *thr, const char *filename, duk_int_t linenumber, const char *message));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_type_invalid_args(duk_hthread *thr, const char *filename, duk_int_t linenumber));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_type_invalid_state(duk_hthread *thr, const char *filename, duk_int_t linenumber));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_type_invalid_trap_result(duk_hthread *thr, const char *filename, duk_int_t linenumber));
#else  /* DUK_VERBOSE_ERRORS */
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_error(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_range(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_eval(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_reference(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_syntax(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_type(duk_hthread *thr));
DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_uri(duk_hthread *thr));
#endif /* DUK_VERBOSE_ERRORS */

DUK_NORETURN(DUK_INTERNAL_DECL void duk_err_longjmp(duk_hthread *thr));

DUK_NORETURN(DUK_INTERNAL_DECL void duk_default_fatal_handler(void *udata, const char *msg));

DUK_INTERNAL_DECL void duk_err_setup_ljstate1(duk_hthread *thr, duk_small_uint_t lj_type, duk_tval *tv_val);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL_DECL void duk_err_check_debugger_integration(duk_hthread *thr);
#endif

DUK_INTERNAL_DECL duk_hobject *duk_error_prototype_from_code(duk_hthread *thr, duk_errcode_t err_code);

#endif  /* DUK_ERROR_H_INCLUDED */
/* #include duk_unicode.h */
/*
 *  Unicode helpers
 */

#if !defined(DUK_UNICODE_H_INCLUDED)
#define DUK_UNICODE_H_INCLUDED

/*
 *  UTF-8 / XUTF-8 / CESU-8 constants
 */

#define DUK_UNICODE_MAX_XUTF8_LENGTH      7   /* up to 36 bit codepoints */
#define DUK_UNICODE_MAX_XUTF8_BMP_LENGTH  3   /* all codepoints up to U+FFFF */
#define DUK_UNICODE_MAX_CESU8_LENGTH      6   /* all codepoints up to U+10FFFF */
#define DUK_UNICODE_MAX_CESU8_BMP_LENGTH  3   /* all codepoints up to U+FFFF */

/*
 *  Useful Unicode codepoints
 *
 *  Integer constants must be signed to avoid unexpected coercions
 *  in comparisons.
 */

#define DUK_UNICODE_CP_ZWNJ                   0x200cL  /* zero-width non-joiner */
#define DUK_UNICODE_CP_ZWJ                    0x200dL  /* zero-width joiner */
#define DUK_UNICODE_CP_REPLACEMENT_CHARACTER  0xfffdL  /* http://en.wikipedia.org/wiki/Replacement_character#Replacement_character */

/*
 *  ASCII character constants
 *
 *  C character literals like 'x' have a platform specific value and do
 *  not match ASCII (UTF-8) values on e.g. EBCDIC platforms.  So, use
 *  these (admittedly awkward) constants instead.  These constants must
 *  also have signed values to avoid unexpected coercions in comparisons.
 *
 *  http://en.wikipedia.org/wiki/ASCII
 */

#define DUK_ASC_NUL              0x00
#define DUK_ASC_SOH              0x01
#define DUK_ASC_STX              0x02
#define DUK_ASC_ETX              0x03
#define DUK_ASC_EOT              0x04
#define DUK_ASC_ENQ              0x05
#define DUK_ASC_ACK              0x06
#define DUK_ASC_BEL              0x07
#define DUK_ASC_BS               0x08
#define DUK_ASC_HT               0x09
#define DUK_ASC_LF               0x0a
#define DUK_ASC_VT               0x0b
#define DUK_ASC_FF               0x0c
#define DUK_ASC_CR               0x0d
#define DUK_ASC_SO               0x0e
#define DUK_ASC_SI               0x0f
#define DUK_ASC_DLE              0x10
#define DUK_ASC_DC1              0x11
#define DUK_ASC_DC2              0x12
#define DUK_ASC_DC3              0x13
#define DUK_ASC_DC4              0x14
#define DUK_ASC_NAK              0x15
#define DUK_ASC_SYN              0x16
#define DUK_ASC_ETB              0x17
#define DUK_ASC_CAN              0x18
#define DUK_ASC_EM               0x19
#define DUK_ASC_SUB              0x1a
#define DUK_ASC_ESC              0x1b
#define DUK_ASC_FS               0x1c
#define DUK_ASC_GS               0x1d
#define DUK_ASC_RS               0x1e
#define DUK_ASC_US               0x1f
#define DUK_ASC_SPACE            0x20
#define DUK_ASC_EXCLAMATION      0x21
#define DUK_ASC_DOUBLEQUOTE      0x22
#define DUK_ASC_HASH             0x23
#define DUK_ASC_DOLLAR           0x24
#define DUK_ASC_PERCENT          0x25
#define DUK_ASC_AMP              0x26
#define DUK_ASC_SINGLEQUOTE      0x27
#define DUK_ASC_LPAREN           0x28
#define DUK_ASC_RPAREN           0x29
#define DUK_ASC_STAR             0x2a
#define DUK_ASC_PLUS             0x2b
#define DUK_ASC_COMMA            0x2c
#define DUK_ASC_MINUS            0x2d
#define DUK_ASC_PERIOD           0x2e
#define DUK_ASC_SLASH            0x2f
#define DUK_ASC_0                0x30
#define DUK_ASC_1                0x31
#define DUK_ASC_2                0x32
#define DUK_ASC_3                0x33
#define DUK_ASC_4                0x34
#define DUK_ASC_5                0x35
#define DUK_ASC_6                0x36
#define DUK_ASC_7                0x37
#define DUK_ASC_8                0x38
#define DUK_ASC_9                0x39
#define DUK_ASC_COLON            0x3a
#define DUK_ASC_SEMICOLON        0x3b
#define DUK_ASC_LANGLE           0x3c
#define DUK_ASC_EQUALS           0x3d
#define DUK_ASC_RANGLE           0x3e
#define DUK_ASC_QUESTION         0x3f
#define DUK_ASC_ATSIGN           0x40
#define DUK_ASC_UC_A             0x41
#define DUK_ASC_UC_B             0x42
#define DUK_ASC_UC_C             0x43
#define DUK_ASC_UC_D             0x44
#define DUK_ASC_UC_E             0x45
#define DUK_ASC_UC_F             0x46
#define DUK_ASC_UC_G             0x47
#define DUK_ASC_UC_H             0x48
#define DUK_ASC_UC_I             0x49
#define DUK_ASC_UC_J             0x4a
#define DUK_ASC_UC_K             0x4b
#define DUK_ASC_UC_L             0x4c
#define DUK_ASC_UC_M             0x4d
#define DUK_ASC_UC_N             0x4e
#define DUK_ASC_UC_O             0x4f
#define DUK_ASC_UC_P             0x50
#define DUK_ASC_UC_Q             0x51
#define DUK_ASC_UC_R             0x52
#define DUK_ASC_UC_S             0x53
#define DUK_ASC_UC_T             0x54
#define DUK_ASC_UC_U             0x55
#define DUK_ASC_UC_V             0x56
#define DUK_ASC_UC_W             0x57
#define DUK_ASC_UC_X             0x58
#define DUK_ASC_UC_Y             0x59
#define DUK_ASC_UC_Z             0x5a
#define DUK_ASC_LBRACKET         0x5b
#define DUK_ASC_BACKSLASH        0x5c
#define DUK_ASC_RBRACKET         0x5d
#define DUK_ASC_CARET            0x5e
#define DUK_ASC_UNDERSCORE       0x5f
#define DUK_ASC_GRAVE            0x60
#define DUK_ASC_LC_A             0x61
#define DUK_ASC_LC_B             0x62
#define DUK_ASC_LC_C             0x63
#define DUK_ASC_LC_D             0x64
#define DUK_ASC_LC_E             0x65
#define DUK_ASC_LC_F             0x66
#define DUK_ASC_LC_G             0x67
#define DUK_ASC_LC_H             0x68
#define DUK_ASC_LC_I             0x69
#define DUK_ASC_LC_J             0x6a
#define DUK_ASC_LC_K             0x6b
#define DUK_ASC_LC_L             0x6c
#define DUK_ASC_LC_M             0x6d
#define DUK_ASC_LC_N             0x6e
#define DUK_ASC_LC_O             0x6f
#define DUK_ASC_LC_P             0x70
#define DUK_ASC_LC_Q             0x71
#define DUK_ASC_LC_R             0x72
#define DUK_ASC_LC_S             0x73
#define DUK_ASC_LC_T             0x74
#define DUK_ASC_LC_U             0x75
#define DUK_ASC_LC_V             0x76
#define DUK_ASC_LC_W             0x77
#define DUK_ASC_LC_X             0x78
#define DUK_ASC_LC_Y             0x79
#define DUK_ASC_LC_Z             0x7a
#define DUK_ASC_LCURLY           0x7b
#define DUK_ASC_PIPE             0x7c
#define DUK_ASC_RCURLY           0x7d
#define DUK_ASC_TILDE            0x7e
#define DUK_ASC_DEL              0x7f

/*
 *  Miscellaneous
 */

/* Uppercase A is 0x41, lowercase a is 0x61; OR 0x20 to convert uppercase
 * to lowercase.
 */
#define DUK_LOWERCASE_CHAR_ASCII(x)  ((x) | 0x20)

/*
 *  Unicode tables
 */

#if defined(DUK_USE_SOURCE_NONBMP)
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_ids_noa[1116];
#else
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_ids_noabmp[625];
#endif

#if defined(DUK_USE_SOURCE_NONBMP)
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_ids_m_let_noa[42];
#else
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_ids_m_let_noabmp[24];
#endif

#if defined(DUK_USE_SOURCE_NONBMP)
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_idp_m_ids_noa[576];
#else
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_idp_m_ids_noabmp[358];
#endif

/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

extern const duk_uint8_t duk_unicode_caseconv_uc[1411];
extern const duk_uint8_t duk_unicode_caseconv_lc[706];

#if defined(DUK_USE_REGEXP_CANON_WORKAROUND)
/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

extern const duk_uint16_t duk_unicode_re_canon_lookup[65536];
#endif

#if defined(DUK_USE_REGEXP_CANON_BITMAP)
/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

#define DUK_CANON_BITMAP_BLKSIZE                                      32
#define DUK_CANON_BITMAP_BLKSHIFT                                     5
#define DUK_CANON_BITMAP_BLKMASK                                      31
extern const duk_uint8_t duk_unicode_re_canon_bitmap[256];
#endif

/*
 *  Extern
 */

/* duk_unicode_support.c */
#if !defined(DUK_SINGLE_FILE)
DUK_INTERNAL_DECL const duk_uint8_t duk_unicode_xutf8_markers[7];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_digit[2];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_white[22];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_wordchar[8];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_not_digit[4];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_not_white[24];
DUK_INTERNAL_DECL const duk_uint16_t duk_unicode_re_ranges_not_wordchar[10];
DUK_INTERNAL_DECL const duk_int8_t duk_is_idchar_tab[128];
#endif  /* !DUK_SINGLE_FILE */

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL duk_small_int_t duk_unicode_get_xutf8_length(duk_ucodepoint_t cp);
#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_get_cesu8_length(duk_ucodepoint_t cp);
#endif
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_encode_xutf8(duk_ucodepoint_t cp, duk_uint8_t *out);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_encode_cesu8(duk_ucodepoint_t cp, duk_uint8_t *out);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_decode_xutf8(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end, duk_ucodepoint_t *out_cp);
DUK_INTERNAL_DECL duk_ucodepoint_t duk_unicode_decode_xutf8_checked(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end);
DUK_INTERNAL_DECL duk_size_t duk_unicode_unvalidated_utf8_length(const duk_uint8_t *data, duk_size_t blen);
DUK_INTERNAL_DECL duk_bool_t duk_unicode_is_utf8_compatible(const duk_uint8_t *buf, duk_size_t len);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_is_whitespace(duk_codepoint_t cp);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_is_line_terminator(duk_codepoint_t cp);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_is_identifier_start(duk_codepoint_t cp);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_is_identifier_part(duk_codepoint_t cp);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_is_letter(duk_codepoint_t cp);
DUK_INTERNAL_DECL void duk_unicode_case_convert_string(duk_hthread *thr, duk_bool_t uppercase);
#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_INTERNAL_DECL duk_codepoint_t duk_unicode_re_canonicalize_char(duk_hthread *thr, duk_codepoint_t cp);
DUK_INTERNAL_DECL duk_small_int_t duk_unicode_re_is_wordchar(duk_codepoint_t cp);
#endif

#endif  /* DUK_UNICODE_H_INCLUDED */
/* #include duk_json.h */
/*
 *  Defines for JSON, especially duk_bi_json.c.
 */

#if !defined(DUK_JSON_H_INCLUDED)
#define DUK_JSON_H_INCLUDED

/* Encoding/decoding flags */
#define DUK_JSON_FLAG_ASCII_ONLY              (1U << 0)  /* escape any non-ASCII characters */
#define DUK_JSON_FLAG_AVOID_KEY_QUOTES        (1U << 1)  /* avoid key quotes when key is an ASCII Identifier */
#define DUK_JSON_FLAG_EXT_CUSTOM              (1U << 2)  /* extended types: custom encoding */
#define DUK_JSON_FLAG_EXT_COMPATIBLE          (1U << 3)  /* extended types: compatible encoding */

/* How much stack to require on entry to object/array encode */
#define DUK_JSON_ENC_REQSTACK                 32

/* How much stack to require on entry to object/array decode */
#define DUK_JSON_DEC_REQSTACK                 32

/* How large a loop detection stack to use */
#define DUK_JSON_ENC_LOOPARRAY                64

/* Encoding state.  Heap object references are all borrowed. */
typedef struct {
	duk_hthread *thr;
	duk_bufwriter_ctx bw;        /* output bufwriter */
	duk_hobject *h_replacer;     /* replacer function */
	duk_hstring *h_gap;          /* gap (if empty string, NULL) */
	duk_idx_t idx_proplist;      /* explicit PropertyList */
	duk_idx_t idx_loop;          /* valstack index of loop detection object */
	duk_small_uint_t flags;
	duk_small_uint_t flag_ascii_only;
	duk_small_uint_t flag_avoid_key_quotes;
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	duk_small_uint_t flag_ext_custom;
	duk_small_uint_t flag_ext_compatible;
	duk_small_uint_t flag_ext_custom_or_compatible;
#endif
	duk_uint_t recursion_depth;
	duk_uint_t recursion_limit;
	duk_uint_t mask_for_undefined;      /* type bit mask: types which certainly produce 'undefined' */
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	duk_small_uint_t stridx_custom_undefined;
	duk_small_uint_t stridx_custom_nan;
	duk_small_uint_t stridx_custom_neginf;
	duk_small_uint_t stridx_custom_posinf;
	duk_small_uint_t stridx_custom_function;
#endif
	duk_hobject *visiting[DUK_JSON_ENC_LOOPARRAY];  /* indexed by recursion_depth */
} duk_json_enc_ctx;

typedef struct {
	duk_hthread *thr;
	const duk_uint8_t *p;
	const duk_uint8_t *p_start;
	const duk_uint8_t *p_end;
	duk_idx_t idx_reviver;
	duk_small_uint_t flags;
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	duk_small_uint_t flag_ext_custom;
	duk_small_uint_t flag_ext_compatible;
	duk_small_uint_t flag_ext_custom_or_compatible;
#endif
	duk_int_t recursion_depth;
	duk_int_t recursion_limit;
} duk_json_dec_ctx;

#endif  /* DUK_JSON_H_INCLUDED */
/* #include duk_js.h */
/*
 *  ECMAScript execution, support primitives.
 */

#if !defined(DUK_JS_H_INCLUDED)
#define DUK_JS_H_INCLUDED

/* Flags for call handling.  Lowest flags must match bytecode DUK_BC_CALL_FLAG_xxx 1:1. */
#define DUK_CALL_FLAG_TAILCALL                 (1U << 0)  /* setup for a tail call */
#define DUK_CALL_FLAG_CONSTRUCT                (1U << 1)  /* constructor call (i.e. called as 'new Foo()') */
#define DUK_CALL_FLAG_CALLED_AS_EVAL           (1U << 2)  /* call was made using the identifier 'eval' */
#define DUK_CALL_FLAG_ALLOW_ECMATOECMA         (1U << 3)  /* ecma-to-ecma call with executor reuse is possible */
#define DUK_CALL_FLAG_DIRECT_EVAL              (1U << 4)  /* call is a direct eval call */
#define DUK_CALL_FLAG_CONSTRUCT_PROXY          (1U << 5)  /* handled via 'construct' proxy trap, check return value invariant(s) */
#define DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED (1U << 6)  /* prototype of 'default instance' updated, temporary flag in call handling */

/* Flags for duk_js_equals_helper(). */
#define DUK_EQUALS_FLAG_SAMEVALUE            (1U << 0)  /* use SameValue instead of non-strict equality */
#define DUK_EQUALS_FLAG_STRICT               (1U << 1)  /* use strict equality instead of non-strict equality */

/* Flags for duk_js_compare_helper(). */
#define DUK_COMPARE_FLAG_NEGATE              (1U << 0)  /* negate result */
#define DUK_COMPARE_FLAG_EVAL_LEFT_FIRST     (1U << 1)  /* eval left argument first */

/* conversions, coercions, comparison, etc */
DUK_INTERNAL_DECL duk_bool_t duk_js_toboolean(duk_tval *tv);
DUK_INTERNAL_DECL duk_double_t duk_js_tonumber(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL duk_double_t duk_js_tointeger_number(duk_double_t x);
DUK_INTERNAL_DECL duk_double_t duk_js_tointeger(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL duk_uint32_t duk_js_touint32(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL duk_int32_t duk_js_toint32(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL duk_uint16_t duk_js_touint16(duk_hthread *thr, duk_tval *tv);
DUK_INTERNAL_DECL duk_uarridx_t duk_js_to_arrayindex_string(const duk_uint8_t *str, duk_uint32_t blen);
#if !defined(DUK_USE_HSTRING_ARRIDX)
DUK_INTERNAL_DECL duk_uarridx_t duk_js_to_arrayindex_hstring_fast_known(duk_hstring *h);
DUK_INTERNAL_DECL duk_uarridx_t duk_js_to_arrayindex_hstring_fast(duk_hstring *h);
#endif
DUK_INTERNAL_DECL duk_bool_t duk_js_equals_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_small_int_t duk_js_data_compare(const duk_uint8_t *buf1, const duk_uint8_t *buf2, duk_size_t len1, duk_size_t len2);
DUK_INTERNAL_DECL duk_small_int_t duk_js_string_compare(duk_hstring *h1, duk_hstring *h2);
#if 0  /* unused */
DUK_INTERNAL_DECL duk_small_int_t duk_js_buffer_compare(duk_heap *heap, duk_hbuffer *h1, duk_hbuffer *h2);
#endif
DUK_INTERNAL_DECL duk_bool_t duk_js_compare_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_bool_t duk_js_instanceof(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y);
#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL_DECL duk_bool_t duk_js_instanceof_ordinary(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y);
#endif
DUK_INTERNAL_DECL duk_bool_t duk_js_in(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y);
DUK_INTERNAL_DECL duk_small_uint_t duk_js_typeof_stridx(duk_tval *tv_x);
DUK_INTERNAL_DECL duk_bool_t duk_js_isarray_hobject(duk_hobject *h);
DUK_INTERNAL_DECL duk_bool_t duk_js_isarray(duk_tval *tv);

/* arithmetic */
DUK_INTERNAL_DECL double duk_js_arith_pow(double x, double y);
DUK_INTERNAL_DECL double duk_js_arith_mod(double x, double y);

#define duk_js_equals(thr,tv_x,tv_y) \
	duk_js_equals_helper((thr), (tv_x), (tv_y), 0)
#define duk_js_strict_equals(tv_x,tv_y) \
	duk_js_equals_helper(NULL, (tv_x), (tv_y), DUK_EQUALS_FLAG_STRICT)
#define duk_js_samevalue(tv_x,tv_y) \
	duk_js_equals_helper(NULL, (tv_x), (tv_y), DUK_EQUALS_FLAG_SAMEVALUE)

/* E5 Sections 11.8.1, 11.8.5; x < y */
#define duk_js_lessthan(thr,tv_x,tv_y) \
	duk_js_compare_helper((thr), (tv_x), (tv_Y), DUK_COMPARE_FLAG_EVAL_LEFT_FIRST)

/* E5 Sections 11.8.2, 11.8.5; x > y  -->  y < x */
#define duk_js_greaterthan(thr,tv_x,tv_y) \
	duk_js_compare_helper((thr), (tv_y), (tv_x), 0)

/* E5 Sections 11.8.3, 11.8.5; x <= y  -->  not (x > y)  -->  not (y < x) */
#define duk_js_lessthanorequal(thr,tv_x,tv_y) \
	duk_js_compare_helper((thr), (tv_y), (tv_x), DUK_COMPARE_FLAG_NEGATE)

/* E5 Sections 11.8.4, 11.8.5; x >= y  -->  not (x < y) */
#define duk_js_greaterthanorequal(thr,tv_x,tv_y) \
	duk_js_compare_helper((thr), (tv_x), (tv_y), DUK_COMPARE_FLAG_EVAL_LEFT_FIRST | DUK_COMPARE_FLAG_NEGATE)

/* identifiers and environment handling */
#if 0  /*unused*/
DUK_INTERNAL duk_bool_t duk_js_hasvar_envrec(duk_hthread *thr, duk_hobject *env, duk_hstring *name);
#endif
DUK_INTERNAL_DECL duk_bool_t duk_js_getvar_envrec(duk_hthread *thr, duk_hobject *env, duk_hstring *name, duk_bool_t throw_flag);
DUK_INTERNAL_DECL duk_bool_t duk_js_getvar_activation(duk_hthread *thr, duk_activation *act, duk_hstring *name, duk_bool_t throw_flag);
DUK_INTERNAL_DECL void duk_js_putvar_envrec(duk_hthread *thr, duk_hobject *env, duk_hstring *name, duk_tval *val, duk_bool_t strict);
DUK_INTERNAL_DECL void duk_js_putvar_activation(duk_hthread *thr, duk_activation *act, duk_hstring *name, duk_tval *val, duk_bool_t strict);
#if 0  /*unused*/
DUK_INTERNAL_DECL duk_bool_t duk_js_delvar_envrec(duk_hthread *thr, duk_hobject *env, duk_hstring *name);
#endif
DUK_INTERNAL_DECL duk_bool_t duk_js_delvar_activation(duk_hthread *thr, duk_activation *act, duk_hstring *name);
DUK_INTERNAL_DECL duk_bool_t duk_js_declvar_activation(duk_hthread *thr, duk_activation *act, duk_hstring *name, duk_tval *val, duk_small_uint_t prop_flags, duk_bool_t is_func_decl);
DUK_INTERNAL_DECL void duk_js_init_activation_environment_records_delayed(duk_hthread *thr, duk_activation *act);
DUK_INTERNAL_DECL void duk_js_close_environment_record(duk_hthread *thr, duk_hobject *env);
DUK_INTERNAL_DECL duk_hobject *duk_create_activation_environment_record(duk_hthread *thr, duk_hobject *func, duk_size_t bottom_byteoff);
DUK_INTERNAL_DECL void duk_js_push_closure(duk_hthread *thr,
                                           duk_hcompfunc *fun_temp,
                                           duk_hobject *outer_var_env,
                                           duk_hobject *outer_lex_env,
                                           duk_bool_t add_auto_proto);

/* call handling */
DUK_INTERNAL_DECL void duk_native_stack_check(duk_hthread *thr);
DUK_INTERNAL_DECL duk_int_t duk_handle_call_unprotected(duk_hthread *thr, duk_idx_t idx_func, duk_small_uint_t call_flags);
DUK_INTERNAL_DECL duk_int_t duk_handle_call_unprotected_nargs(duk_hthread *thr, duk_idx_t nargs, duk_small_uint_t call_flags);
DUK_INTERNAL_DECL duk_int_t duk_handle_safe_call(duk_hthread *thr, duk_safe_call_function func, void *udata, duk_idx_t num_stack_args, duk_idx_t num_stack_res);
DUK_INTERNAL_DECL void duk_call_construct_postprocess(duk_hthread *thr, duk_small_uint_t proxy_invariant);
#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_INTERNAL_DECL void duk_call_setup_propcall_error(duk_hthread *thr, duk_tval *tv_base, duk_tval *tv_key);
#endif

/* bytecode execution */
DUK_INTERNAL_DECL void duk_js_execute_bytecode(duk_hthread *exec_thr);

#endif  /* DUK_JS_H_INCLUDED */
/* #include duk_numconv.h */
/*
 *  Number-to-string conversion.  The semantics of these is very tightly
 *  bound with the ECMAScript semantics required for call sites.
 */

#if !defined(DUK_NUMCONV_H_INCLUDED)
#define DUK_NUMCONV_H_INCLUDED

/* Output a specified number of digits instead of using the shortest
 * form.  Used for toPrecision() and toFixed().
 */
#define DUK_N2S_FLAG_FIXED_FORMAT         (1U << 0)

/* Force exponential format.  Used for toExponential(). */
#define DUK_N2S_FLAG_FORCE_EXP            (1U << 1)

/* If number would need zero padding (for whole number part), use
 * exponential format instead.  E.g. if input number is 12300, 3
 * digits are generated ("123"), output "1.23e+4" instead of "12300".
 * Used for toPrecision().
 */
#define DUK_N2S_FLAG_NO_ZERO_PAD          (1U << 2)

/* Digit count indicates number of fractions (i.e. an absolute
 * digit index instead of a relative one).  Used together with
 * DUK_N2S_FLAG_FIXED_FORMAT for toFixed().
 */
#define DUK_N2S_FLAG_FRACTION_DIGITS      (1U << 3)

/*
 *  String-to-number conversion
 */

/* Maximum exponent value when parsing numbers.  This is not strictly
 * compliant as there should be no upper limit, but as we parse the
 * exponent without a bigint, impose some limit.  The limit should be
 * small enough that multiplying it (or limit-1 to be precise) won't
 * overflow signed 32-bit integer range.  Exponent is only parsed with
 * radix 10, but with maximum radix (36) a safe limit is:
 * (10000000*36).toString(16) -> '15752a00'
 */
#define DUK_S2N_MAX_EXPONENT              10000000L

/* Trim white space (= allow leading and trailing whitespace) */
#define DUK_S2N_FLAG_TRIM_WHITE           (1U << 0)

/* Allow exponent */
#define DUK_S2N_FLAG_ALLOW_EXP            (1U << 1)

/* Allow trailing garbage (e.g. treat "123foo" as "123) */
#define DUK_S2N_FLAG_ALLOW_GARBAGE        (1U << 2)

/* Allow leading plus sign */
#define DUK_S2N_FLAG_ALLOW_PLUS           (1U << 3)

/* Allow leading minus sign */
#define DUK_S2N_FLAG_ALLOW_MINUS          (1U << 4)

/* Allow 'Infinity' */
#define DUK_S2N_FLAG_ALLOW_INF            (1U << 5)

/* Allow fraction part */
#define DUK_S2N_FLAG_ALLOW_FRAC           (1U << 6)

/* Allow naked fraction (e.g. ".123") */
#define DUK_S2N_FLAG_ALLOW_NAKED_FRAC     (1U << 7)

/* Allow empty fraction (e.g. "123.") */
#define DUK_S2N_FLAG_ALLOW_EMPTY_FRAC     (1U << 8)

/* Allow empty string to be interpreted as 0 */
#define DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO  (1U << 9)

/* Allow leading zeroes (e.g. "0123" -> "123") */
#define DUK_S2N_FLAG_ALLOW_LEADING_ZERO   (1U << 10)

/* Allow automatic detection of hex base ("0x" or "0X" prefix),
 * overrides radix argument and forces integer mode.
 */
#define DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT   (1U << 11)

/* Allow automatic detection of legacy octal base ("0n"),
 * overrides radix argument and forces integer mode.
 */
#define DUK_S2N_FLAG_ALLOW_AUTO_LEGACY_OCT_INT   (1U << 12)

/* Allow automatic detection of ES2015 octal base ("0o123"),
 * overrides radix argument and forces integer mode.
 */
#define DUK_S2N_FLAG_ALLOW_AUTO_OCT_INT   (1U << 13)

/* Allow automatic detection of ES2015 binary base ("0b10001"),
 * overrides radix argument and forces integer mode.
 */
#define DUK_S2N_FLAG_ALLOW_AUTO_BIN_INT   (1U << 14)

/*
 *  Prototypes
 */

DUK_INTERNAL_DECL void duk_numconv_stringify(duk_hthread *thr, duk_small_int_t radix, duk_small_int_t digits, duk_small_uint_t flags);
DUK_INTERNAL_DECL void duk_numconv_parse(duk_hthread *thr, duk_small_int_t radix, duk_small_uint_t flags);

#endif  /* DUK_NUMCONV_H_INCLUDED */
/* #include duk_bi_protos.h */
/*
 *  Prototypes for built-in functions not automatically covered by the
 *  header declarations emitted by genbuiltins.py.
 */

#if !defined(DUK_BUILTIN_PROTOS_H_INCLUDED)
#define DUK_BUILTIN_PROTOS_H_INCLUDED

/* Buffer size needed for ISO 8601 formatting.
 * Accurate value is 32 + 1 for NUL termination:
 *   >>> len('+123456-01-23T12:34:56.123+12:34')
 *   32
 * Include additional space to be safe.
 */
#define  DUK_BI_DATE_ISO8601_BUFSIZE  40

/* Helpers exposed for internal use */
DUK_INTERNAL_DECL void duk_bi_date_timeval_to_parts(duk_double_t d, duk_int_t *parts, duk_double_t *dparts, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_timeval_from_dparts(duk_double_t *dparts, duk_small_uint_t flags);
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_is_leap_year(duk_int_t year);
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_timeval_in_valid_range(duk_double_t x);
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_year_in_valid_range(duk_double_t year);
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_timeval_in_leeway_range(duk_double_t x);
/* Built-in providers */
#if defined(DUK_USE_DATE_NOW_GETTIMEOFDAY)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_now_gettimeofday(void);
#endif
#if defined(DUK_USE_DATE_NOW_TIME)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_now_time(void);
#endif
#if defined(DUK_USE_DATE_NOW_WINDOWS)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_now_windows(void);
#endif
#if defined(DUK_USE_DATE_NOW_WINDOWS_SUBMS)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_now_windows_subms(void);
#endif
#if defined(DUK_USE_DATE_TZO_GMTIME_R) || defined(DUK_USE_DATE_TZO_GMTIME_S) || defined(DUK_USE_DATE_TZO_GMTIME)
DUK_INTERNAL_DECL duk_int_t duk_bi_date_get_local_tzoffset_gmtime(duk_double_t d);
#endif
#if defined(DUK_USE_DATE_TZO_WINDOWS)
DUK_INTERNAL_DECL duk_int_t duk_bi_date_get_local_tzoffset_windows(duk_double_t d);
#endif
#if defined(DUK_USE_DATE_TZO_WINDOWS_NO_DST)
DUK_INTERNAL_DECL duk_int_t duk_bi_date_get_local_tzoffset_windows_no_dst(duk_double_t d);
#endif
#if defined(DUK_USE_DATE_PRS_STRPTIME)
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_parse_string_strptime(duk_hthread *thr, const char *str);
#endif
#if defined(DUK_USE_DATE_PRS_GETDATE)
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_parse_string_getdate(duk_hthread *thr, const char *str);
#endif
#if defined(DUK_USE_DATE_FMT_STRFTIME)
DUK_INTERNAL_DECL duk_bool_t duk_bi_date_format_parts_strftime(duk_hthread *thr, duk_int_t *parts, duk_int_t tzoffset, duk_small_uint_t flags);
#endif

#if defined(DUK_USE_GET_MONOTONIC_TIME_CLOCK_GETTIME)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_monotonic_time_clock_gettime(void);
#endif
#if defined(DUK_USE_GET_MONOTONIC_TIME_WINDOWS_QPC)
DUK_INTERNAL_DECL duk_double_t duk_bi_date_get_monotonic_time_windows_qpc(void);
#endif

DUK_INTERNAL_DECL
void duk_bi_json_parse_helper(duk_hthread *thr,
                              duk_idx_t idx_value,
                              duk_idx_t idx_reviver,
                              duk_small_uint_t flags);
DUK_INTERNAL_DECL
void duk_bi_json_stringify_helper(duk_hthread *thr,
                                  duk_idx_t idx_value,
                                  duk_idx_t idx_replacer,
                                  duk_idx_t idx_space,
                                  duk_small_uint_t flags);

DUK_INTERNAL_DECL duk_ret_t duk_textdecoder_decode_utf8_nodejs(duk_hthread *thr);

#if defined(DUK_USE_ES6_PROXY)
DUK_INTERNAL_DECL void duk_proxy_ownkeys_postprocess(duk_hthread *thr, duk_hobject *h_proxy_target, duk_uint_t flags);
#endif

#endif  /* DUK_BUILTIN_PROTOS_H_INCLUDED */
/* #include duk_selftest.h */
/*
 *  Selftest code
 */

#if !defined(DUK_SELFTEST_H_INCLUDED)
#define DUK_SELFTEST_H_INCLUDED

#if defined(DUK_USE_SELF_TESTS)
DUK_INTERNAL_DECL duk_uint_t duk_selftest_run_tests(duk_alloc_function alloc_func,
                                                    duk_realloc_function realloc_func,
                                                    duk_free_function free_func,
                                                    void *udata);
#endif

#endif  /* DUK_SELFTEST_H_INCLUDED */

#endif  /* DUK_INTERNAL_H_INCLUDED */

#if defined(DUK_USE_COMPUTED_NAN)
DUK_INTERNAL double duk_computed_nan;
#endif

#if defined(DUK_USE_COMPUTED_INFINITY)
DUK_INTERNAL double duk_computed_infinity;
#endif

#if defined(DUK_USE_REPL_FPCLASSIFY)
DUK_INTERNAL int duk_repl_fpclassify(double x) {
	duk_double_union u;
	duk_uint_fast16_t expt;
	duk_small_int_t mzero;

	u.d = x;
	expt = (duk_uint_fast16_t) (u.us[DUK_DBL_IDX_US0] & 0x7ff0UL);
	if (expt > 0x0000UL && expt < 0x7ff0UL) {
		/* expt values [0x001,0x7fe] = normal */
		return DUK_FP_NORMAL;
	}

	mzero = (u.ui[DUK_DBL_IDX_UI1] == 0 && (u.ui[DUK_DBL_IDX_UI0] & 0x000fffffUL) == 0);
	if (expt == 0x0000UL) {
		/* expt 0x000 is zero/subnormal */
		if (mzero) {
			return DUK_FP_ZERO;
		} else {
			return DUK_FP_SUBNORMAL;
		}
	} else {
		/* expt 0xfff is infinite/nan */
		if (mzero) {
			return DUK_FP_INFINITE;
		} else {
			return DUK_FP_NAN;
		}
	}
}
#endif

#if defined(DUK_USE_REPL_SIGNBIT)
DUK_INTERNAL int duk_repl_signbit(double x) {
	duk_double_union u;
	u.d = x;
	return (int) (u.uc[DUK_DBL_IDX_UC0] & 0x80UL);
}
#endif

#if defined(DUK_USE_REPL_ISFINITE)
DUK_INTERNAL int duk_repl_isfinite(double x) {
	int c = DUK_FPCLASSIFY(x);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		return 0;
	} else {
		return 1;
	}
}
#endif

#if defined(DUK_USE_REPL_ISNAN)
DUK_INTERNAL int duk_repl_isnan(double x) {
	int c = DUK_FPCLASSIFY(x);
	return (c == DUK_FP_NAN);
}
#endif

#if defined(DUK_USE_REPL_ISINF)
DUK_INTERNAL int duk_repl_isinf(double x) {
	int c = DUK_FPCLASSIFY(x);
	return (c == DUK_FP_INFINITE);
}
#endif
/*
 *  Debugging macro calls.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_DEBUG)

/*
 *  Debugging enabled
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#if !defined(DUK_USE_DEBUG_WRITE)
#error debugging enabled (DUK_USE_DEBUG) but DUK_USE_DEBUG_WRITE not defined
#endif

#define DUK__DEBUG_BUFSIZE  DUK_USE_DEBUG_BUFSIZE

#if defined(DUK_USE_VARIADIC_MACROS)

DUK_INTERNAL void duk_debug_log(duk_int_t level, const char *file, duk_int_t line, const char *func, const char *fmt, ...) {
	va_list ap;
	long arg_level;
	const char *arg_file;
	long arg_line;
	const char *arg_func;
	const char *arg_msg;
	char buf[DUK__DEBUG_BUFSIZE];

	va_start(ap, fmt);

	duk_memzero((void *) buf, (size_t) DUK__DEBUG_BUFSIZE);
	duk_debug_vsnprintf(buf, DUK__DEBUG_BUFSIZE - 1, fmt, ap);

	arg_level = (long) level;
	arg_file = (const char *) file;
	arg_line = (long) line;
	arg_func = (const char *) func;
	arg_msg = (const char *) buf;
	DUK_USE_DEBUG_WRITE(arg_level, arg_file, arg_line, arg_func, arg_msg);

	va_end(ap);
}

#else  /* DUK_USE_VARIADIC_MACROS */

DUK_INTERNAL char duk_debug_file_stash[DUK_DEBUG_STASH_SIZE];
DUK_INTERNAL duk_int_t duk_debug_line_stash;
DUK_INTERNAL char duk_debug_func_stash[DUK_DEBUG_STASH_SIZE];
DUK_INTERNAL duk_int_t duk_debug_level_stash;

DUK_INTERNAL void duk_debug_log(const char *fmt, ...) {
	va_list ap;
	long arg_level;
	const char *arg_file;
	long arg_line;
	const char *arg_func;
	const char *arg_msg;
	char buf[DUK__DEBUG_BUFSIZE];

	va_start(ap, fmt);

	duk_memzero((void *) buf, (size_t) DUK__DEBUG_BUFSIZE);
	duk_debug_vsnprintf(buf, DUK__DEBUG_BUFSIZE - 1, fmt, ap);

	arg_level = (long) duk_debug_level_stash;
	arg_file = (const char *) duk_debug_file_stash;
	arg_line = (long) duk_debug_line_stash;
	arg_func = (const char *) duk_debug_func_stash;
	arg_msg = (const char *) buf;
	DUK_USE_DEBUG_WRITE(arg_level, arg_file, arg_line, arg_func, arg_msg);

	va_end(ap);
}

#endif  /* DUK_USE_VARIADIC_MACROS */

#else  /* DUK_USE_DEBUG */

/*
 *  Debugging disabled
 */

#endif  /* DUK_USE_DEBUG */

/* automatic undefs */
#undef DUK__DEBUG_BUFSIZE
/*
 *  Automatically generated by genbuiltins.py, do not edit!
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ASSERTIONS)
#define DUK__REFCINIT(refc) 0 /*h_assert_refcount*/, (refc) /*actual*/
#else
#define DUK__REFCINIT(refc) (refc) /*actual*/
#endif

#if defined(DUK_USE_ROM_STRINGS)
#error ROM support not enabled, rerun configure.py with --rom-support
#else  /* DUK_USE_ROM_STRINGS */
DUK_INTERNAL const duk_uint8_t duk_strings_data[972] = {
79,40,209,144,168,105,6,78,54,139,89,185,44,48,46,90,120,8,154,140,35,103,
35,113,193,73,5,52,112,180,104,166,135,52,188,4,98,12,27,146,156,80,211,31,
129,115,150,64,52,220,109,24,18,68,156,24,38,67,114,36,55,9,119,151,132,
140,93,18,113,128,153,201,212,201,205,2,248,8,196,24,224,104,82,146,40,224,
193,48,114,168,37,147,196,54,123,28,4,98,12,43,148,67,103,177,192,70,32,
196,121,68,54,123,28,18,192,199,144,124,4,98,12,43,136,108,244,117,184,8,
196,24,95,40,134,207,71,91,128,140,65,133,113,13,158,158,151,1,24,131,11,
229,16,217,233,233,112,17,136,48,206,21,110,4,244,244,184,8,196,24,103,10,
183,2,122,218,156,4,98,12,24,203,112,64,179,113,193,79,8,218,155,131,32,
184,70,212,220,13,10,82,68,252,123,144,217,146,38,228,207,18,0,100,37,64,
178,212,11,161,17,104,162,96,10,200,193,57,165,65,169,16,5,100,81,27,70,18,
32,10,200,68,185,13,116,221,197,184,64,89,57,41,197,13,49,234,5,208,156,
113,87,55,118,147,20,187,56,161,166,92,221,212,73,210,236,226,134,153,115,
119,76,201,203,179,138,26,99,73,212,136,136,164,25,174,137,56,32,72,137,
101,23,52,45,13,34,86,9,79,136,104,201,114,149,96,52,138,134,140,151,75,
226,233,186,120,121,22,39,54,83,141,5,55,68,236,36,164,3,16,225,115,150,64,
52,205,163,2,72,154,83,138,26,99,75,12,11,150,103,5,36,20,211,70,140,133,
67,72,49,241,160,227,81,196,52,168,106,39,132,252,183,136,105,80,212,79,2,
249,110,128,126,88,95,133,109,237,237,237,151,235,127,46,249,119,203,190,
186,206,33,181,2,208,61,190,12,19,34,65,19,81,132,108,228,97,1,107,33,12,
32,45,100,137,64,247,175,9,19,155,41,198,130,155,134,69,146,100,227,226,
231,146,51,192,204,73,140,224,145,221,102,241,68,196,169,248,30,75,12,11,
151,242,233,187,143,138,24,137,162,164,255,253,63,3,201,97,129,114,254,92,
112,75,136,108,166,6,136,159,255,167,224,121,44,48,46,95,203,166,238,74,
113,67,77,201,128,223,255,223,224,121,44,48,46,95,203,145,46,9,205,16,39,
201,62,36,0,192,21,147,255,238,145,39,199,197,211,116,240,242,113,197,78,
214,211,226,233,187,107,105,19,119,37,56,161,166,52,221,212,201,205,36,240,
242,16,96,152,12,26,20,164,137,150,70,154,103,28,137,50,202,96,18,132,241,
41,104,105,56,218,48,36,138,183,57,56,128,68,24,38,2,52,12,34,10,133,147,
141,3,8,119,185,13,153,34,125,206,76,17,49,38,93,206,52,151,154,119,56,28,
76,130,112,200,141,206,21,209,96,23,35,238,114,160,139,0,243,238,114,78,
164,68,68,110,113,226,210,90,26,66,110,113,128,121,247,57,80,68,141,170,
183,56,84,52,11,70,73,19,110,114,160,93,8,113,57,143,66,200,84,53,244,154,
73,24,240,81,32,38,68,18,49,228,207,23,88,100,109,70,114,92,193,4,137,173,
168,36,220,73,19,247,247,182,168,209,144,187,223,58,156,104,79,190,183,127,
123,105,160,110,247,206,167,26,19,239,173,223,222,218,67,75,189,243,169,
198,132,251,235,183,247,182,154,134,151,123,231,83,141,9,247,215,111,239,
109,22,141,22,247,206,167,26,19,239,172,223,218,45,26,47,157,78,52,39,223,
74,24,144,10,32,129,34,20,64,152,142,129,57,179,67,104,68,12,129,161,140,
72,156,100,40,40,185,152,100,89,38,65,13,196,34,228,67,149,13,2,215,129,
149,209,65,104,209,77,14,104,144,81,33,170,67,101,48,52,68,113,70,210,88,
209,36,233,22,154,86,68,196,114,76,232,145,102,120,186,195,156,112,105,225,
228,113,71,80,68,162,115,101,50,85,200,25,108,116,44,132,178,38,114,137,96,
148,136,70,209,134,37,222,232,204,228,188,200,209,200,200,99,221,25,150,84,
121,34,70,209,107,36,227,66,20,160,92,136,164,49,235,35,8,217,201,40,108,
201,18,128,68,26,201,51,188,2,80,12,67,190,40,168,38,68,190,46,153,5,50,12,
207,160,86,129,26,83,4,208,34,225,4,88,192,
};
#endif  /* DUK_USE_ROM_STRINGS */

#if defined(DUK_USE_ROM_OBJECTS)
#error ROM support not enabled, rerun configure.py with --rom-support
#else  /* DUK_USE_ROM_OBJECTS */
/* native functions: 185 */
DUK_INTERNAL const duk_c_function duk_bi_native_functions[185] = {
	NULL,
	duk_bi_array_constructor,
	duk_bi_array_constructor_is_array,
	duk_bi_array_prototype_concat,
	duk_bi_array_prototype_indexof_shared,
	duk_bi_array_prototype_iter_shared,
	duk_bi_array_prototype_join_shared,
	duk_bi_array_prototype_pop,
	duk_bi_array_prototype_push,
	duk_bi_array_prototype_reduce_shared,
	duk_bi_array_prototype_reverse,
	duk_bi_array_prototype_shift,
	duk_bi_array_prototype_slice,
	duk_bi_array_prototype_sort,
	duk_bi_array_prototype_splice,
	duk_bi_array_prototype_to_string,
	duk_bi_array_prototype_unshift,
	duk_bi_arraybuffer_constructor,
	duk_bi_arraybuffer_isview,
	duk_bi_boolean_constructor,
	duk_bi_boolean_prototype_tostring_shared,
	duk_bi_buffer_compare_shared,
	duk_bi_buffer_readfield,
	duk_bi_buffer_slice_shared,
	duk_bi_buffer_writefield,
	duk_bi_cbor_decode,
	duk_bi_cbor_encode,
	duk_bi_dataview_constructor,
	duk_bi_date_constructor,
	duk_bi_date_constructor_now,
	duk_bi_date_constructor_parse,
	duk_bi_date_constructor_utc,
	duk_bi_date_prototype_get_shared,
	duk_bi_date_prototype_get_timezone_offset,
	duk_bi_date_prototype_set_shared,
	duk_bi_date_prototype_set_time,
	duk_bi_date_prototype_to_json,
	duk_bi_date_prototype_toprimitive,
	duk_bi_date_prototype_tostring_shared,
	duk_bi_date_prototype_value_of,
	duk_bi_duktape_object_act,
	duk_bi_duktape_object_compact,
	duk_bi_duktape_object_dec,
	duk_bi_duktape_object_enc,
	duk_bi_duktape_object_fin,
	duk_bi_duktape_object_gc,
	duk_bi_duktape_object_info,
	duk_bi_error_constructor_shared,
	duk_bi_error_prototype_filename_getter,
	duk_bi_error_prototype_filename_setter,
	duk_bi_error_prototype_linenumber_getter,
	duk_bi_error_prototype_linenumber_setter,
	duk_bi_error_prototype_stack_getter,
	duk_bi_error_prototype_stack_setter,
	duk_bi_error_prototype_to_string,
	duk_bi_function_constructor,
	duk_bi_function_prototype,
	duk_bi_function_prototype_apply,
	duk_bi_function_prototype_bind,
	duk_bi_function_prototype_call,
	duk_bi_function_prototype_hasinstance,
	duk_bi_function_prototype_to_string,
	duk_bi_global_object_decode_uri,
	duk_bi_global_object_decode_uri_component,
	duk_bi_global_object_encode_uri,
	duk_bi_global_object_encode_uri_component,
	duk_bi_global_object_escape,
	duk_bi_global_object_eval,
	duk_bi_global_object_is_finite,
	duk_bi_global_object_is_nan,
	duk_bi_global_object_parse_float,
	duk_bi_global_object_parse_int,
	duk_bi_global_object_unescape,
	duk_bi_json_object_parse,
	duk_bi_json_object_stringify,
	duk_bi_math_object_clz32,
	duk_bi_math_object_hypot,
	duk_bi_math_object_imul,
	duk_bi_math_object_max,
	duk_bi_math_object_min,
	duk_bi_math_object_onearg_shared,
	duk_bi_math_object_random,
	duk_bi_math_object_sign,
	duk_bi_math_object_twoarg_shared,
	duk_bi_native_function_length,
	duk_bi_native_function_name,
	duk_bi_nodejs_buffer_byte_length,
	duk_bi_nodejs_buffer_concat,
	duk_bi_nodejs_buffer_constructor,
	duk_bi_nodejs_buffer_copy,
	duk_bi_nodejs_buffer_fill,
	duk_bi_nodejs_buffer_is_buffer,
	duk_bi_nodejs_buffer_is_encoding,
	duk_bi_nodejs_buffer_tojson,
	duk_bi_nodejs_buffer_tostring,
	duk_bi_nodejs_buffer_write,
	duk_bi_number_check_shared,
	duk_bi_number_constructor,
	duk_bi_number_prototype_to_exponential,
	duk_bi_number_prototype_to_fixed,
	duk_bi_number_prototype_to_locale_string,
	duk_bi_number_prototype_to_precision,
	duk_bi_number_prototype_to_string,
	duk_bi_number_prototype_value_of,
	duk_bi_object_constructor,
	duk_bi_object_constructor_assign,
	duk_bi_object_constructor_create,
	duk_bi_object_constructor_define_properties,
	duk_bi_object_constructor_define_property,
	duk_bi_object_constructor_get_own_property_descriptor,
	duk_bi_object_constructor_is,
	duk_bi_object_constructor_is_extensible,
	duk_bi_object_constructor_is_sealed_frozen_shared,
	duk_bi_object_constructor_keys_shared,
	duk_bi_object_constructor_prevent_extensions,
	duk_bi_object_constructor_seal_freeze_shared,
	duk_bi_object_getprototype_shared,
	duk_bi_object_prototype_defineaccessor,
	duk_bi_object_prototype_has_own_property,
	duk_bi_object_prototype_is_prototype_of,
	duk_bi_object_prototype_lookupaccessor,
	duk_bi_object_prototype_property_is_enumerable,
	duk_bi_object_prototype_to_locale_string,
	duk_bi_object_prototype_to_string,
	duk_bi_object_prototype_value_of,
	duk_bi_object_setprototype_shared,
	duk_bi_performance_now,
	duk_bi_pointer_constructor,
	duk_bi_pointer_prototype_tostring_shared,
	duk_bi_proxy_constructor,
	duk_bi_reflect_apply,
	duk_bi_reflect_construct,
	duk_bi_reflect_object_delete_property,
	duk_bi_reflect_object_get,
	duk_bi_reflect_object_has,
	duk_bi_reflect_object_set,
	duk_bi_regexp_constructor,
	duk_bi_regexp_prototype_exec,
	duk_bi_regexp_prototype_flags,
	duk_bi_regexp_prototype_shared_getter,
	duk_bi_regexp_prototype_test,
	duk_bi_regexp_prototype_tostring,
	duk_bi_string_constructor,
	duk_bi_string_constructor_from_char_code,
	duk_bi_string_constructor_from_code_point,
	duk_bi_string_prototype_caseconv_shared,
	duk_bi_string_prototype_char_at,
	duk_bi_string_prototype_char_code_at,
	duk_bi_string_prototype_concat,
	duk_bi_string_prototype_includes,
	duk_bi_string_prototype_indexof_shared,
	duk_bi_string_prototype_locale_compare,
	duk_bi_string_prototype_match,
	duk_bi_string_prototype_repeat,
	duk_bi_string_prototype_replace,
	duk_bi_string_prototype_search,
	duk_bi_string_prototype_slice,
	duk_bi_string_prototype_split,
	duk_bi_string_prototype_startswith_endswith,
	duk_bi_string_prototype_substr,
	duk_bi_string_prototype_substring,
	duk_bi_string_prototype_to_string,
	duk_bi_string_prototype_trim,
	duk_bi_symbol_constructor_shared,
	duk_bi_symbol_key_for,
	duk_bi_symbol_toprimitive,
	duk_bi_symbol_tostring_shared,
	duk_bi_textdecoder_constructor,
	duk_bi_textdecoder_prototype_decode,
	duk_bi_textdecoder_prototype_shared_getter,
	duk_bi_textencoder_constructor,
	duk_bi_textencoder_prototype_encode,
	duk_bi_textencoder_prototype_encoding_getter,
	duk_bi_thread_constructor,
	duk_bi_thread_current,
	duk_bi_thread_resume,
	duk_bi_thread_yield,
	duk_bi_type_error_thrower,
	duk_bi_typedarray_buffer_getter,
	duk_bi_typedarray_bytelength_getter,
	duk_bi_typedarray_byteoffset_getter,
	duk_bi_typedarray_constructor,
	duk_bi_typedarray_set,
	duk_bi_uint8array_allocplain,
	duk_bi_uint8array_plainof,
};
#if defined(DUK_USE_DOUBLE_LE)
DUK_INTERNAL const duk_uint8_t duk_builtins_data[4281] = {
144,148,105,226,32,68,52,228,254,12,104,202,37,132,52,167,194,138,105,245,
124,57,28,211,57,18,64,52,239,126,44,138,111,175,241,164,19,87,145,30,33,
167,22,145,159,8,211,139,9,225,42,5,240,145,139,163,163,8,211,139,10,228,
64,211,19,132,140,93,29,56,70,156,88,119,34,66,146,36,104,137,194,70,46,
142,172,35,78,44,47,146,195,102,11,240,145,139,163,175,8,211,139,9,228,240,
242,112,145,139,163,179,8,211,139,8,237,34,130,118,49,116,118,225,26,48,0,
1,98,29,201,158,46,183,39,135,147,132,140,93,16,132,76,66,33,8,66,16,132,
33,8,66,26,180,105,97,167,68,150,34,33,154,112,0,1,91,247,35,79,111,237,
198,174,232,47,31,23,95,17,13,31,249,96,211,49,50,53,214,77,141,24,0,0,181,
10,228,240,242,15,128,140,65,128,134,188,0,0,90,167,97,181,224,0,2,213,62,
53,224,0,2,213,66,237,120,0,0,181,81,204,107,192,0,5,170,150,67,94,0,0,45,
84,245,90,240,0,1,106,169,162,215,128,0,11,85,93,150,188,0,0,90,171,111,53,
109,22,162,26,48,0,1,84,23,201,146,243,225,26,39,12,145,136,104,192,0,5,61,
11,228,201,121,240,100,19,134,72,196,33,195,14,40,203,112,64,190,76,232,
145,153,136,0,0,0,0,0,0,31,15,249,152,0,0,0,0,0,0,30,15,249,120,144,13,96,
155,194,56,80,206,36,67,141,20,228,70,57,81,206,100,131,156,39,132,168,23,
194,70,46,137,208,21,200,129,166,39,9,24,186,39,72,119,34,66,146,36,104,
137,194,70,46,137,212,23,201,97,179,5,248,72,197,209,58,194,121,60,60,156,
36,98,232,157,129,29,164,80,78,198,46,137,218,146,121,25,71,146,9,209,5,
209,61,48,126,14,138,152,30,67,186,23,143,139,175,131,202,135,228,72,85,
144,83,60,179,30,94,209,233,102,30,98,105,230,103,30,114,121,231,104,30,
122,137,231,233,30,130,153,232,106,30,138,169,232,235,30,144,67,193,25,19,
136,108,207,30,41,224,140,137,194,173,192,153,228,5,242,100,188,248,70,137,
195,36,79,78,47,147,37,231,193,144,78,25,34,122,145,111,36,74,232,176,13,
17,61,234,226,93,207,148,160,84,75,141,7,27,161,32,33,18,225,80,212,76,154,
2,2,70,65,56,100,237,34,140,209,2,67,32,156,50,118,145,64,186,230,61,205,
35,103,155,32,36,141,19,134,78,210,40,206,16,36,70,137,195,39,105,20,11,
174,99,220,210,54,121,210,1,137,33,1,228,207,16,17,70,146,66,3,201,164,32,
0,65,112,152,56,196,159,31,23,77,211,195,201,199,23,160,72,214,246,81,6,12,
73,241,214,111,31,23,60,145,158,56,50,72,81,67,230,232,242,80,19,49,39,199,
89,188,124,92,242,70,120,227,64,194,75,154,72,12,9,73,6,111,21,120,12,40,
144,19,39,25,0,225,144,168,105,56,248,185,228,140,241,200,96,64,100,42,26,
78,62,46,121,35,52,18,92,116,1,36,64,47,158,64,49,98,66,100,156,242,65,23,
196,149,35,103,194,94,100,108,144,230,203,156,64,66,37,201,16,11,32,249,
132,4,34,92,44,93,146,55,152,72,24,137,112,151,153,27,36,5,100,229,144,8,
162,98,92,210,5,76,73,241,214,111,31,23,60,145,158,57,44,48,46,92,185,164,
160,72,151,41,0,50,107,179,244,59,36,93,127,92,6,19,172,3,11,216,0,56,224,
151,29,102,241,241,115,201,25,227,164,64,106,37,199,197,211,116,240,242,
113,197,233,144,40,248,185,228,140,241,196,75,132,109,24,72,128,43,39,84,
129,13,173,161,144,168,105,56,98,78,100,142,214,215,69,1,13,173,161,144,
168,105,57,34,78,100,142,214,215,69,16,67,107,105,110,114,168,254,24,147,
153,35,181,181,212,32,67,107,105,110,114,168,254,72,147,153,35,181,181,212,
36,65,130,3,144,8,26,252,200,13,30,85,16,16,64,90,242,231,192,64,161,163,
203,31,26,172,193,17,4,23,105,159,96,27,172,251,16,32,196,4,14,137,112,17,
136,48,164,28,134,80,215,202,1,132,130,8,12,39,52,64,155,31,24,56,36,1,189,
207,132,0,35,233,35,195,62,3,196,149,36,100,72,160,2,200,232,44,227,0,11,
37,160,68,142,128,36,157,25,200,32,26,79,90,4,73,43,192,122,54,71,65,103,
44,248,14,134,140,151,227,138,231,208,45,96,148,248,134,140,151,227,138,
231,240,1,255,254,10,74,146,56,128,104,4,147,152,72,6,144,28,174,143,8,1,
30,1,165,3,96,31,0,211,3,21,11,153,35,0,211,131,68,131,160,137,16,250,5,
196,131,160,137,200,160,199,156,67,248,0,255,255,65,140,10,48,177,115,56,
35,130,60,19,134,79,89,240,52,177,115,56,39,12,156,123,144,217,251,15,135,
34,167,30,20,170,154,255,232,12,47,244,0,97,28,17,224,39,238,32,40,71,4,
120,39,12,156,4,253,228,5,137,195,39,30,228,54,124,4,253,228,128,194,115,
68,9,252,15,128,232,104,201,126,56,191,35,64,90,193,41,241,13,25,47,199,23,
228,105,3,86,225,1,100,224,156,199,130,36,249,144,10,192,76,71,250,16,15,
18,61,96,17,62,200,3,72,128,136,143,247,32,22,75,64,137,248,64,22,79,90,39,
249,64,38,84,12,167,20,52,223,196,2,230,238,45,214,36,120,32,72,158,208,4,
102,238,45,194,2,201,197,186,196,143,4,9,19,218,0,92,221,202,61,228,143,4,
9,19,218,8,35,55,113,110,16,22,78,81,239,36,120,32,72,158,208,64,73,197,12,
255,0,13,18,60,128,159,212,128,169,76,17,156,185,100,76,255,163,64,65,26,
57,114,200,153,255,70,144,33,13,18,232,50,75,226,104,6,149,3,41,199,246,
130,12,128,28,142,156,120,203,175,158,8,194,207,1,6,81,20,79,88,11,237,84,
11,161,32,127,255,255,255,255,255,247,191,137,235,16,221,170,129,116,36,0,
16,0,0,0,0,0,0,12,196,0,0,0,0,0,0,15,135,242,61,123,164,137,162,164,218,67,
74,134,162,120,128,0,0,0,0,0,1,224,254,71,173,33,129,52,84,155,72,105,80,
212,79,16,0,0,0,0,0,0,60,63,195,244,143,146,22,230,192,0,0,0,0,0,0,176,60,
33,214,2,251,82,1,73,180,134,204,134,36,96,127,255,255,255,255,255,159,161,
144,235,16,221,169,0,164,218,67,102,67,18,48,63,255,255,255,255,255,207,
240,196,60,17,145,56,134,204,241,226,158,8,200,156,42,220,9,158,65,196,34,
92,42,26,137,147,120,64,74,37,196,54,100,49,35,188,36,5,68,184,208,113,187,
194,80,212,75,146,1,73,196,54,100,49,35,188,38,57,37,56,240,0,0,0,0,0,0,0,
0,32,235,248,68,48,156,2,24,94,24,0,243,119,10,139,144,123,242,3,102,238,
18,239,115,72,217,160,11,223,16,23,55,113,241,32,145,36,57,188,18,16,102,3,
5,120,35,34,89,32,15,180,152,173,127,0,218,235,88,0,228,180,227,200,0,0,0,
0,0,0,248,127,197,107,240,64,6,77,220,24,38,78,74,113,67,77,130,4,12,155,
185,52,48,156,148,226,134,155,4,10,194,96,129,132,166,238,45,194,2,201,193,
130,100,228,167,20,52,216,32,113,41,187,139,112,128,178,114,104,97,57,41,
197,13,54,8,32,48,216,32,130,195,224,130,19,97,124,134,23,6,0,57,137,62,77,
12,38,12,0,179,18,124,45,22,190,96,128,141,176,134,28,98,79,180,152,139,
218,45,124,193,1,27,97,16,32,196,159,24,230,204,246,194,40,89,137,62,210,
98,103,92,217,158,216,70,7,49,39,193,130,100,182,17,194,140,73,246,147,16,
250,9,146,216,72,6,49,39,193,131,22,194,72,73,137,62,210,98,31,65,139,97,
40,32,196,159,14,234,70,86,194,88,89,137,62,210,98,63,93,72,202,216,76,10,
49,39,198,33,180,153,37,108,38,134,152,147,237,38,38,117,13,164,201,43,97,
56,40,196,159,36,65,57,163,149,176,158,26,98,79,180,152,165,210,9,205,28,
173,133,0,243,18,124,98,22,180,72,130,115,71,43,97,68,72,196,159,105,49,51,
168,90,209,34,9,205,28,173,133,33,19,18,124,154,24,76,185,164,227,138,89,
18,119,0,7,145,39,201,161,132,188,64,124,137,62,49,11,90,36,65,57,163,149,
210,166,37,34,79,180,152,153,212,45,104,145,4,230,142,87,74,160,84,137,62,
72,130,115,71,43,171,234,134,200,147,237,38,41,116,130,115,71,43,171,235,5,
72,147,227,16,218,76,146,186,254,184,108,137,62,210,98,103,80,218,76,146,
186,254,192,68,137,62,29,212,140,174,207,178,23,34,79,180,152,143,215,82,
50,187,62,208,60,137,62,12,19,37,210,182,21,34,79,180,152,135,208,76,151,
74,224,68,137,62,49,205,153,238,175,186,23,34,79,180,152,153,215,54,103,
186,190,240,92,137,62,22,139,95,48,64,70,235,251,225,210,36,251,73,136,189,
162,215,204,16,17,186,255,2,14,98,79,152,32,35,108,48,64,242,36,249,130,2,
55,75,6,212,224,72,200,51,128,114,108,28,100,128,0,0,0,0,0,0,0,12,110,127,
48,98,115,249,201,117,243,249,195,21,159,206,38,47,63,156,86,8,75,144,94,
82,1,38,73,79,208,67,95,233,1,6,128,14,79,129,186,40,249,18,149,182,207,
144,200,155,188,248,204,105,184,207,142,199,137,175,201,0,159,72,10,5,21,
221,10,120,74,129,124,36,98,232,228,74,81,62,160,20,10,107,186,21,114,32,
105,137,194,70,46,142,68,165,19,235,1,64,170,187,161,119,34,66,146,36,104,
137,194,70,46,142,68,165,19,236,1,64,174,187,161,95,37,134,204,23,225,35,
23,71,34,82,137,246,128,160,89,93,208,167,147,195,201,194,70,46,142,68,165,
19,238,1,64,182,187,161,71,105,20,19,177,139,163,145,41,68,16,7,6,15,82,70,
72,115,96,0,0,0,0,0,2,234,32,91,60,165,195,201,194,8,134,149,216,162,0,192,
41,225,8,2,48,177,36,1,149,13,196,15,0,200,209,97,199,128,99,32,176,195,
192,113,57,143,0,167,133,32,230,80,28,202,139,175,238,2,48,189,192,20,1,
119,80,87,193,186,129,89,56,72,197,209,200,193,185,35,23,71,109,13,219,36,
98,232,237,156,13,26,208,211,14,102,19,87,137,91,95,128,0,10,96,24,92,0,0,
83,2,53,56,0,0,165,3,28,204,160,160,226,100,226,200,211,76,241,240,0,1,102,
8,22,75,64,137,73,20,230,105,133,7,19,39,22,70,154,103,143,128,0,11,48,20,
28,76,156,113,75,34,78,62,0,0,45,3,103,31,0,0,22,65,44,57,137,62,33,179,
216,162,152,192,131,18,124,162,27,61,138,41,108,32,196,159,16,217,232,235,
81,76,104,73,137,62,81,13,158,142,181,20,184,16,98,79,136,108,244,244,168,
166,56,36,196,159,40,134,207,79,74,138,93,10,49,39,194,173,192,158,158,149,
20,188,20,98,79,133,91,129,61,109,74,41,124,30,68,159,16,217,236,83,108,96,
68,137,62,81,13,158,197,54,182,17,34,79,136,108,244,117,169,182,52,38,68,
159,40,134,207,71,90,155,92,8,145,39,196,54,122,122,84,219,28,19,34,79,148,
67,103,167,165,77,174,133,72,147,225,86,224,79,79,74,155,94,10,145,39,194,
173,192,158,182,165,54,190,206,25,212,35,208,226,100,150,211,201,29,162,44,
140,35,103,0,0,0,0,0,0,3,192,252,206,25,228,35,208,226,100,150,211,201,29,
162,44,140,35,103,0,0,0,0,0,0,3,192,252,206,25,244,35,208,226,100,150,211,
201,29,162,44,140,35,103,0,0,0,0,0,0,3,192,252,206,26,4,35,208,226,100,150,
211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,1,0,206,26,20,35,208,226,100,
150,211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,1,0,206,26,36,35,208,226,
100,150,211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,65,0,206,26,52,35,208,
226,100,150,211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,65,0,206,26,68,35,
208,226,100,150,211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,65,0,206,26,84,
35,208,226,100,150,211,201,29,162,44,140,35,103,0,0,0,0,0,0,0,129,0,195,
154,99,16,38,36,0,251,68,117,179,216,162,128,68,72,1,241,13,158,197,20,150,
25,18,0,125,162,58,217,232,235,117,100,162,136,25,18,0,125,162,58,217,232,
235,116,36,162,145,2,226,64,15,136,108,244,117,186,178,81,73,129,113,32,7,
196,54,122,58,221,9,40,165,64,200,144,3,237,17,214,207,79,75,171,37,20,80,
200,144,3,237,17,214,207,79,75,161,37,20,138,23,18,0,124,67,103,167,165,
213,146,138,77,11,137,0,62,33,179,211,210,232,73,69,42,133,196,128,31,10,
183,2,125,89,40,163,5,196,128,31,10,183,2,125,9,40,164,96,200,144,3,224,
221,64,172,157,89,40,163,134,68,128,31,6,234,5,100,232,73,69,35,133,68,128,
31,104,142,182,125,89,40,180,0,168,144,3,237,17,214,207,161,37,22,144,19,
18,0,124,67,103,213,146,139,80,9,137,0,62,33,179,232,73,69,172,5,90,40,153,
59,68,117,179,216,166,192,77,162,137,147,136,108,246,41,180,176,219,69,19,
39,104,142,182,122,58,221,89,41,178,6,218,40,153,59,68,117,179,209,214,232,
73,77,162,6,90,40,153,56,134,207,71,91,171,37,54,152,25,104,162,100,226,27,
61,29,110,132,148,218,160,109,162,137,147,180,71,91,61,61,46,172,148,217,
67,109,20,76,157,162,58,217,233,233,116,36,166,209,67,45,20,76,156,67,103,
167,165,213,146,155,77,12,180,81,50,113,13,158,158,151,66,74,109,84,50,209,
68,201,194,173,192,159,86,74,108,193,150,138,38,78,21,110,4,250,18,83,104,
193,182,138,38,78,13,212,10,201,213,146,155,56,109,162,137,147,131,117,2,
178,116,36,166,209,194,237,20,76,157,162,58,217,245,100,167,16,2,237,20,76,
157,162,58,217,244,36,167,18,2,173,20,76,156,67,103,213,146,156,80,10,180,
81,50,113,13,159,66,74,113,97,175,221,48,216,110,64,4,42,22,189,179,0,196,
133,0,185,80,32,28,78,99,193,18,80,36,4,19,159,141,172,0,178,90,4,74,73,0,
22,209,68,201,187,129,4,2,8,3,132,64,60,36,6,149,113,72,176,171,240,84,0,
157,91,116,116,32,11,42,218,221,216,181,129,32,3,234,219,165,3,188,231,235,
249,8,187,152,252,47,86,227,105,18,7,244,17,91,42,56,175,185,248,110,173,
198,209,208,36,0,238,82,97,87,188,189,179,240,93,122,32,12,22,162,42,125,
144,132,160,7,236,161,25,232,237,105,64,205,59,127,102,158,160,230,63,11,
217,66,51,210,129,154,118,254,205,61,65,236,127,171,197,34,168,48,6,90,194,
1,0,39,75,88,72,8,9,33,186,194,80,64,76,13,214,19,2,130,96,110,150,189,0,
65,6,51,214,20,128,65,17,11,214,19,130,137,121,211,210,211,144,6,39,75,88,
80,0,201,119,235,10,8,41,86,231,71,88,80,129,79,135,186,122,133,224,34,25,
69,234,80,3,91,141,172,40,96,139,113,180,181,133,36,21,110,54,142,134,176,
165,1,176,23,213,47,0,216,134,234,215,128,111,117,181,232,128,209,3,70,230,
107,64,5,139,168,209,235,10,32,36,144,102,235,136,3,146,27,172,40,160,146,
132,103,172,40,192,115,3,117,133,28,22,113,163,69,172,41,103,1,66,188,17,
145,52,168,4,202,113,67,76,130,227,76,194,13,240,108,0,0,83,224,0,2,193,0,
104,146,84,97,48,0,1,94,192,56,169,24,145,179,192,0,5,112,8,56,16,32,128,
56,18,52,125,230,86,147,190,140,28,50,21,13,39,31,23,60,145,158,57,12,141,
47,129,6,155,194,188,24,49,39,199,89,188,124,92,242,70,120,224,201,33,69,
15,155,163,201,68,14,49,39,199,197,211,116,240,242,113,197,232,18,180,254,
36,3,17,46,18,243,35,100,128,172,156,178,70,163,154,76,34,248,146,164,108,
248,75,204,141,146,28,217,115,137,27,95,27,241,173,236,162,160,224,200,2,
206,9,113,13,148,192,209,18,22,164,146,37,193,57,162,4,249,39,196,128,24,2,
178,66,213,136,68,201,16,77,209,131,31,192,242,88,96,92,191,151,34,100,136,
38,232,255,252,92,221,199,197,12,68,209,82,66,212,11,155,185,41,197,13,55,
38,3,66,213,47,135,254,72,12,162,99,133,116,112,0,1,72,66,14,16,16,50,37,
202,160,150,154,66,14,20,8,57,192,28,24,80,113,50,113,100,105,166,120,248,
0,0,179,1,65,196,201,199,20,178,36,227,224,0,2,208,54,113,240,0,1,100,11,
181,192,0,5,178,1,18,160,65,24,131,20,145,25,188,48,132,122,28,76,146,218,
121,35,180,69,145,132,108,224,0,0,0,0,0,0,120,31,153,188,56,132,122,28,76,
146,218,121,35,180,69,145,132,108,224,0,0,0,0,0,0,120,31,168,160,45,110,23,
30,176,33,184,0,0,183,32,29,235,2,27,199,23,0,0,23,4,51,120,129,8,244,56,
153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,240,63,51,120,145,8,244,
56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,0,64,51,120,161,8,
244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,0,64,51,120,177,
8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,16,64,51,120,
193,8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,16,64,51,
120,209,8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,16,64,
51,120,225,8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,0,0,0,32,
64,32,227,194,0,97,57,162,4,246,104,5,34,92,35,68,225,161,166,220,16,16,
137,112,52,41,73,29,185,1,65,196,201,197,145,166,153,246,72,3,137,204,120,
34,74,8,199,1,67,17,162,112,201,84,128,97,144,78,25,42,16,131,169,1,205,66,
8,35,68,225,161,166,239,128,0,10,192,64,196,104,156,50,96,0,2,172,73,240,
117,96,57,170,97,4,104,156,52,52,221,240,0,1,82,1,74,9,129,125,240,0,1,82,
32,148,25,174,137,58,23,51,190,0,0,42,69,64,195,32,156,50,96,0,2,160,81,
238,2,3,107,173,218,3,192,
};
#elif defined(DUK_USE_DOUBLE_BE)
DUK_INTERNAL const duk_uint8_t duk_builtins_data[4281] = {
144,148,105,226,32,68,52,228,254,12,104,202,37,132,52,167,194,138,105,245,
124,57,28,211,57,18,64,52,239,126,44,138,111,175,241,164,19,87,145,30,33,
167,22,145,159,8,211,139,9,225,42,5,240,145,139,163,163,8,211,139,10,228,
64,211,19,132,140,93,29,56,70,156,88,119,34,66,146,36,104,137,194,70,46,
142,172,35,78,44,47,146,195,102,11,240,145,139,163,175,8,211,139,9,228,240,
242,112,145,139,163,179,8,211,139,8,237,34,130,118,49,116,118,225,26,48,0,
1,98,29,201,158,46,183,39,135,147,132,140,93,16,132,76,66,33,8,66,16,132,
33,8,66,26,180,105,97,167,68,150,34,33,154,112,0,1,91,247,35,79,111,237,
198,174,232,47,31,23,95,17,13,31,249,96,211,49,50,53,214,77,141,24,0,0,181,
10,228,240,242,15,128,140,65,128,134,188,0,0,90,167,97,181,224,0,2,213,62,
53,224,0,2,213,66,237,120,0,0,181,81,204,107,192,0,5,170,150,67,94,0,0,45,
84,245,90,240,0,1,106,169,162,215,128,0,11,85,93,150,188,0,0,90,171,111,53,
109,22,162,26,48,0,1,84,23,201,146,243,225,26,39,12,145,136,104,192,0,5,61,
11,228,201,121,240,100,19,134,72,196,33,195,14,40,203,112,64,190,76,232,
145,153,136,15,255,0,0,0,0,0,0,25,152,15,254,0,0,0,0,0,0,25,120,144,13,96,
155,194,56,80,206,36,67,141,20,228,70,57,81,206,100,131,156,39,132,168,23,
194,70,46,137,208,21,200,129,166,39,9,24,186,39,72,119,34,66,146,36,104,
137,194,70,46,137,212,23,201,97,179,5,248,72,197,209,58,194,121,60,60,156,
36,98,232,157,129,29,164,80,78,198,46,137,218,146,121,25,71,146,9,209,5,
209,61,48,126,14,138,152,30,67,186,23,143,139,175,131,202,135,228,72,85,
144,83,60,179,30,94,209,233,102,30,98,105,230,103,30,114,121,231,104,30,
122,137,231,233,30,130,153,232,106,30,138,169,232,235,30,144,67,193,25,19,
136,108,207,30,41,224,140,137,194,173,192,153,228,5,242,100,188,248,70,137,
195,36,79,78,47,147,37,231,193,144,78,25,34,122,145,111,36,74,232,176,13,
17,61,234,226,93,207,148,160,84,75,141,7,27,161,32,33,18,225,80,212,76,154,
2,2,70,65,56,100,237,34,140,209,2,67,32,156,50,118,145,64,186,230,61,205,
35,103,155,32,36,141,19,134,78,210,40,206,16,36,70,137,195,39,105,20,11,
174,99,220,210,54,121,210,1,137,33,1,228,207,16,17,70,146,66,3,201,164,32,
0,65,112,152,56,196,159,31,23,77,211,195,201,199,23,160,72,214,246,81,6,12,
73,241,214,111,31,23,60,145,158,56,50,72,81,67,230,232,242,80,19,49,39,199,
89,188,124,92,242,70,120,227,64,194,75,154,72,12,9,73,6,111,21,120,12,40,
144,19,39,25,0,225,144,168,105,56,248,185,228,140,241,200,96,64,100,42,26,
78,62,46,121,35,52,18,92,116,1,36,64,47,158,64,49,98,66,100,156,242,65,23,
196,149,35,103,194,94,100,108,144,230,203,156,64,66,37,201,16,11,32,249,
132,4,34,92,44,93,146,55,152,72,24,137,112,151,153,27,36,5,100,229,144,8,
162,98,92,210,5,76,73,241,214,111,31,23,60,145,158,57,44,48,46,92,185,164,
160,72,151,41,0,50,107,179,244,59,36,93,127,92,6,19,172,3,11,216,0,56,224,
151,29,102,241,241,115,201,25,227,164,64,106,37,199,197,211,116,240,242,
113,197,233,144,40,248,185,228,140,241,196,75,132,109,24,72,128,43,39,84,
129,13,173,161,144,168,105,56,98,78,100,142,214,215,69,1,13,173,161,144,
168,105,57,34,78,100,142,214,215,69,16,67,107,105,110,114,168,254,24,147,
153,35,181,181,212,32,67,107,105,110,114,168,254,72,147,153,35,181,181,212,
36,65,130,3,144,8,26,252,200,13,30,85,16,16,64,90,242,231,192,64,161,163,
203,31,26,172,193,17,4,23,105,159,96,27,172,251,16,32,196,4,14,137,112,17,
136,48,164,28,134,80,215,202,1,132,130,8,12,39,52,64,155,31,24,56,36,1,189,
207,132,0,35,233,35,195,62,3,196,149,36,100,72,160,2,200,232,44,227,0,11,
37,160,68,142,128,36,157,25,200,32,26,79,90,4,73,43,192,122,54,71,65,103,
44,248,14,134,140,151,227,138,231,208,45,96,148,248,134,140,151,227,138,
231,240,1,255,254,10,74,146,56,128,104,4,147,152,72,6,144,28,174,143,8,1,
30,1,165,3,96,31,0,211,3,21,11,153,35,0,211,131,68,131,160,137,16,250,5,
196,131,160,137,200,160,199,156,67,248,0,255,255,65,140,10,48,177,115,56,
35,130,60,19,134,79,89,240,52,177,115,56,39,12,156,123,144,217,251,15,135,
34,167,30,20,170,154,255,232,12,47,244,0,97,28,17,224,39,238,32,40,71,4,
120,39,12,156,4,253,228,5,137,195,39,30,228,54,124,4,253,228,128,194,115,
68,9,252,15,128,232,104,201,126,56,191,35,64,90,193,41,241,13,25,47,199,23,
228,105,3,86,225,1,100,224,156,199,130,36,249,144,10,192,76,71,250,16,15,
18,61,96,17,62,200,3,72,128,136,143,247,32,22,75,64,137,248,64,22,79,90,39,
249,64,38,84,12,167,20,52,223,196,2,230,238,45,214,36,120,32,72,158,208,4,
102,238,45,194,2,201,197,186,196,143,4,9,19,218,0,92,221,202,61,228,143,4,
9,19,218,8,35,55,113,110,16,22,78,81,239,36,120,32,72,158,208,64,73,197,12,
255,0,13,18,60,128,159,212,128,169,76,17,156,185,100,76,255,163,64,65,26,
57,114,200,153,255,70,144,33,13,18,232,50,75,226,104,6,149,3,41,199,246,
130,12,128,28,142,156,120,203,175,158,8,194,207,1,6,81,20,79,88,11,237,84,
11,161,32,63,247,255,255,255,255,255,255,137,235,16,221,170,129,116,36,0,0,
0,0,0,0,0,0,28,196,7,255,128,0,0,0,0,0,2,61,123,164,137,162,164,218,67,74,
134,162,120,128,255,224,0,0,0,0,0,0,71,173,33,129,52,84,155,72,105,80,212,
79,16,63,252,0,0,0,0,0,0,3,244,143,146,22,230,192,60,176,0,0,0,0,0,0,33,
214,2,251,82,1,73,180,134,204,134,36,96,33,159,255,255,255,255,255,255,144,
235,16,221,169,0,164,218,67,102,67,18,48,48,207,255,255,255,255,255,255,
196,60,17,145,56,134,204,241,226,158,8,200,156,42,220,9,158,65,196,34,92,
42,26,137,147,120,64,74,37,196,54,100,49,35,188,36,5,68,184,208,113,187,
194,80,212,75,146,1,73,196,54,100,49,35,188,38,57,37,56,240,0,0,0,0,0,0,0,
0,32,235,248,68,48,156,2,24,94,24,0,243,119,10,139,144,123,242,3,102,238,
18,239,115,72,217,160,11,223,16,23,55,113,241,32,145,36,57,188,18,16,102,3,
5,120,35,34,89,32,15,180,152,173,127,0,218,235,88,0,228,180,227,200,127,
248,0,0,0,0,0,0,197,107,240,64,6,77,220,24,38,78,74,113,67,77,130,4,12,155,
185,52,48,156,148,226,134,155,4,10,194,96,129,132,166,238,45,194,2,201,193,
130,100,228,167,20,52,216,32,113,41,187,139,112,128,178,114,104,97,57,41,
197,13,54,8,32,48,216,32,130,195,224,130,19,97,124,134,23,6,0,57,137,62,77,
12,38,12,0,179,18,124,45,22,190,96,128,141,176,134,28,98,79,180,152,139,
218,45,124,193,1,27,97,16,32,196,159,24,230,204,246,194,40,89,137,62,210,
98,103,92,217,158,216,70,7,49,39,193,130,100,182,17,194,140,73,246,147,16,
250,9,146,216,72,6,49,39,193,131,22,194,72,73,137,62,210,98,31,65,139,97,
40,32,196,159,14,234,70,86,194,88,89,137,62,210,98,63,93,72,202,216,76,10,
49,39,198,33,180,153,37,108,38,134,152,147,237,38,38,117,13,164,201,43,97,
56,40,196,159,36,65,57,163,149,176,158,26,98,79,180,152,165,210,9,205,28,
173,133,0,243,18,124,98,22,180,72,130,115,71,43,97,68,72,196,159,105,49,51,
168,90,209,34,9,205,28,173,133,33,19,18,124,154,24,76,185,164,227,138,89,
18,119,0,7,145,39,201,161,132,188,64,124,137,62,49,11,90,36,65,57,163,149,
210,166,37,34,79,180,152,153,212,45,104,145,4,230,142,87,74,160,84,137,62,
72,130,115,71,43,171,234,134,200,147,237,38,41,116,130,115,71,43,171,235,5,
72,147,227,16,218,76,146,186,254,184,108,137,62,210,98,103,80,218,76,146,
186,254,192,68,137,62,29,212,140,174,207,178,23,34,79,180,152,143,215,82,
50,187,62,208,60,137,62,12,19,37,210,182,21,34,79,180,152,135,208,76,151,
74,224,68,137,62,49,205,153,238,175,186,23,34,79,180,152,153,215,54,103,
186,190,240,92,137,62,22,139,95,48,64,70,235,251,225,210,36,251,73,136,189,
162,215,204,16,17,186,255,2,14,98,79,152,32,35,108,48,64,242,36,249,130,2,
55,75,6,212,224,72,200,51,128,114,108,28,100,128,0,0,0,0,0,0,0,12,110,127,
48,98,115,249,201,117,243,249,195,21,159,206,38,47,63,156,86,8,75,144,94,
82,1,38,73,79,208,67,95,233,1,6,128,14,79,129,186,40,249,18,149,182,207,
144,200,155,188,248,204,105,184,207,142,199,137,175,201,0,159,72,10,5,21,
221,10,120,74,129,124,36,98,232,228,74,81,62,160,20,10,107,186,21,114,32,
105,137,194,70,46,142,68,165,19,235,1,64,170,187,161,119,34,66,146,36,104,
137,194,70,46,142,68,165,19,236,1,64,174,187,161,95,37,134,204,23,225,35,
23,71,34,82,137,246,128,160,89,93,208,167,147,195,201,194,70,46,142,68,165,
19,238,1,64,182,187,161,71,105,20,19,177,139,163,145,41,68,16,7,6,15,82,70,
72,115,96,32,106,2,128,0,0,0,0,91,60,165,195,201,194,8,134,149,216,162,0,
192,41,225,8,2,48,177,36,1,149,13,196,15,0,200,209,97,199,128,99,32,176,
195,192,113,57,143,0,167,133,32,230,80,28,202,139,175,238,2,48,189,192,20,
1,119,80,87,193,186,129,89,56,72,197,209,200,193,185,35,23,71,109,13,219,
36,98,232,237,156,13,26,208,211,14,102,19,87,137,91,95,128,0,10,96,24,92,0,
0,83,2,53,56,0,0,165,3,28,204,160,160,226,100,226,200,211,76,241,240,0,1,
102,8,22,75,64,137,73,20,230,105,133,7,19,39,22,70,154,103,143,128,0,11,48,
20,28,76,156,113,75,34,78,62,0,0,45,3,103,31,0,0,22,65,44,57,137,62,33,179,
216,162,152,192,131,18,124,162,27,61,138,41,108,32,196,159,16,217,232,235,
81,76,104,73,137,62,81,13,158,142,181,20,184,16,98,79,136,108,244,244,168,
166,56,36,196,159,40,134,207,79,74,138,93,10,49,39,194,173,192,158,158,149,
20,188,20,98,79,133,91,129,61,109,74,41,124,30,68,159,16,217,236,83,108,96,
68,137,62,81,13,158,197,54,182,17,34,79,136,108,244,117,169,182,52,38,68,
159,40,134,207,71,90,155,92,8,145,39,196,54,122,122,84,219,28,19,34,79,148,
67,103,167,165,77,174,133,72,147,225,86,224,79,79,74,155,94,10,145,39,194,
173,192,158,182,165,54,190,206,25,212,35,208,226,100,150,211,201,29,162,44,
140,35,103,0,255,192,0,0,0,0,0,0,206,25,228,35,208,226,100,150,211,201,29,
162,44,140,35,103,0,255,192,0,0,0,0,0,0,206,25,244,35,208,226,100,150,211,
201,29,162,44,140,35,103,0,255,192,0,0,0,0,0,0,206,26,4,35,208,226,100,150,
211,201,29,162,44,140,35,103,1,0,0,0,0,0,0,0,0,206,26,20,35,208,226,100,
150,211,201,29,162,44,140,35,103,1,0,0,0,0,0,0,0,0,206,26,36,35,208,226,
100,150,211,201,29,162,44,140,35,103,1,0,64,0,0,0,0,0,0,206,26,52,35,208,
226,100,150,211,201,29,162,44,140,35,103,1,0,64,0,0,0,0,0,0,206,26,68,35,
208,226,100,150,211,201,29,162,44,140,35,103,1,0,64,0,0,0,0,0,0,206,26,84,
35,208,226,100,150,211,201,29,162,44,140,35,103,1,0,128,0,0,0,0,0,0,195,
154,99,16,38,36,0,251,68,117,179,216,162,128,68,72,1,241,13,158,197,20,150,
25,18,0,125,162,58,217,232,235,117,100,162,136,25,18,0,125,162,58,217,232,
235,116,36,162,145,2,226,64,15,136,108,244,117,186,178,81,73,129,113,32,7,
196,54,122,58,221,9,40,165,64,200,144,3,237,17,214,207,79,75,171,37,20,80,
200,144,3,237,17,214,207,79,75,161,37,20,138,23,18,0,124,67,103,167,165,
213,146,138,77,11,137,0,62,33,179,211,210,232,73,69,42,133,196,128,31,10,
183,2,125,89,40,163,5,196,128,31,10,183,2,125,9,40,164,96,200,144,3,224,
221,64,172,157,89,40,163,134,68,128,31,6,234,5,100,232,73,69,35,133,68,128,
31,104,142,182,125,89,40,180,0,168,144,3,237,17,214,207,161,37,22,144,19,
18,0,124,67,103,213,146,139,80,9,137,0,62,33,179,232,73,69,172,5,90,40,153,
59,68,117,179,216,166,192,77,162,137,147,136,108,246,41,180,176,219,69,19,
39,104,142,182,122,58,221,89,41,178,6,218,40,153,59,68,117,179,209,214,232,
73,77,162,6,90,40,153,56,134,207,71,91,171,37,54,152,25,104,162,100,226,27,
61,29,110,132,148,218,160,109,162,137,147,180,71,91,61,61,46,172,148,217,
67,109,20,76,157,162,58,217,233,233,116,36,166,209,67,45,20,76,156,67,103,
167,165,213,146,155,77,12,180,81,50,113,13,158,158,151,66,74,109,84,50,209,
68,201,194,173,192,159,86,74,108,193,150,138,38,78,21,110,4,250,18,83,104,
193,182,138,38,78,13,212,10,201,213,146,155,56,109,162,137,147,131,117,2,
178,116,36,166,209,194,237,20,76,157,162,58,217,245,100,167,16,2,237,20,76,
157,162,58,217,244,36,167,18,2,173,20,76,156,67,103,213,146,156,80,10,180,
81,50,113,13,159,66,74,113,97,175,221,48,216,110,64,4,42,22,189,179,0,196,
133,0,185,80,32,28,78,99,193,18,80,36,4,19,159,141,172,0,178,90,4,74,73,0,
22,209,68,201,187,129,4,2,8,3,132,64,60,36,4,0,91,240,168,177,69,118,144,
157,91,116,116,32,32,1,53,216,221,218,170,139,3,234,219,165,0,255,152,185,
11,251,232,231,188,47,86,227,105,18,1,255,184,170,59,41,92,23,240,110,173,
198,209,208,36,3,253,188,183,177,82,110,80,224,93,122,32,32,4,144,253,170,
34,22,140,7,236,161,25,232,237,105,64,63,230,160,158,102,127,59,205,11,217,
66,51,210,128,127,237,65,60,204,254,119,155,171,197,34,168,48,6,90,194,1,0,
39,75,88,72,8,9,33,186,194,80,64,76,13,214,19,2,130,96,110,150,189,0,65,6,
51,214,20,128,65,17,11,214,19,130,137,121,211,210,211,144,6,39,75,88,80,0,
201,119,235,10,8,41,86,231,71,88,80,129,79,135,186,122,133,224,34,25,69,
234,80,3,91,141,172,40,96,139,113,180,181,133,36,21,110,54,142,134,176,165,
1,176,23,213,47,0,216,134,234,215,128,111,117,181,232,128,209,3,70,230,107,
64,5,139,168,209,235,10,32,36,144,102,235,136,3,146,27,172,40,160,146,132,
103,172,40,192,115,3,117,133,28,22,113,163,69,172,41,103,1,66,188,17,145,
52,168,4,202,113,67,76,130,227,76,194,13,240,108,0,0,83,224,0,2,193,0,104,
146,84,97,48,0,1,94,192,56,169,24,145,179,192,0,5,112,8,56,16,32,128,56,18,
52,125,230,86,147,190,140,28,50,21,13,39,31,23,60,145,158,57,12,141,47,129,
6,155,194,188,24,49,39,199,89,188,124,92,242,70,120,224,201,33,69,15,155,
163,201,68,14,49,39,199,197,211,116,240,242,113,197,232,18,180,254,36,3,17,
46,18,243,35,100,128,172,156,178,70,163,154,76,34,248,146,164,108,248,75,
204,141,146,28,217,115,137,27,95,27,241,173,236,162,160,224,200,2,206,9,
113,13,148,192,209,18,22,164,146,37,193,57,162,4,249,39,196,128,24,2,178,
66,213,136,68,201,16,77,209,131,31,192,242,88,96,92,191,151,34,100,136,38,
232,255,252,92,221,199,197,12,68,209,82,66,212,11,155,185,41,197,13,55,38,
3,66,213,47,135,254,72,12,162,99,133,116,112,0,1,72,66,14,16,16,50,37,202,
160,150,154,66,14,20,8,57,192,28,24,80,113,50,113,100,105,166,120,248,0,0,
179,1,65,196,201,199,20,178,36,227,224,0,2,208,54,113,240,0,1,100,11,181,
192,0,5,178,1,18,160,65,24,131,20,145,25,188,48,132,122,28,76,146,218,121,
35,180,69,145,132,108,224,31,248,0,0,0,0,0,0,25,188,56,132,122,28,76,146,
218,121,35,180,69,145,132,108,224,31,248,0,0,0,0,0,0,40,160,45,110,23,30,
176,33,184,0,0,183,32,29,235,2,27,199,23,0,0,23,4,51,120,129,8,244,56,153,
37,180,242,71,104,139,35,8,217,192,63,240,0,0,0,0,0,0,51,120,145,8,244,56,
153,37,180,242,71,104,139,35,8,217,192,64,0,0,0,0,0,0,0,51,120,161,8,244,
56,153,37,180,242,71,104,139,35,8,217,192,64,0,0,0,0,0,0,0,51,120,177,8,
244,56,153,37,180,242,71,104,139,35,8,217,192,64,16,0,0,0,0,0,0,51,120,193,
8,244,56,153,37,180,242,71,104,139,35,8,217,192,64,16,0,0,0,0,0,0,51,120,
209,8,244,56,153,37,180,242,71,104,139,35,8,217,192,64,16,0,0,0,0,0,0,51,
120,225,8,244,56,153,37,180,242,71,104,139,35,8,217,192,64,32,0,0,0,0,0,0,
32,227,194,0,97,57,162,4,246,104,5,34,92,35,68,225,161,166,220,16,16,137,
112,52,41,73,29,185,1,65,196,201,197,145,166,153,246,72,3,137,204,120,34,
74,8,199,1,67,17,162,112,201,84,128,97,144,78,25,42,16,131,169,1,205,66,8,
35,68,225,161,166,239,128,0,10,192,64,196,104,156,50,96,0,2,172,73,240,117,
96,57,170,97,4,104,156,52,52,221,240,0,1,82,1,74,9,129,125,240,0,1,82,32,
148,25,174,137,58,23,51,190,0,0,42,69,64,195,32,156,50,96,0,2,160,81,238,2,
3,107,173,218,3,192,
};
#elif defined(DUK_USE_DOUBLE_ME)
DUK_INTERNAL const duk_uint8_t duk_builtins_data[4281] = {
144,148,105,226,32,68,52,228,254,12,104,202,37,132,52,167,194,138,105,245,
124,57,28,211,57,18,64,52,239,126,44,138,111,175,241,164,19,87,145,30,33,
167,22,145,159,8,211,139,9,225,42,5,240,145,139,163,163,8,211,139,10,228,
64,211,19,132,140,93,29,56,70,156,88,119,34,66,146,36,104,137,194,70,46,
142,172,35,78,44,47,146,195,102,11,240,145,139,163,175,8,211,139,9,228,240,
242,112,145,139,163,179,8,211,139,8,237,34,130,118,49,116,118,225,26,48,0,
1,98,29,201,158,46,183,39,135,147,132,140,93,16,132,76,66,33,8,66,16,132,
33,8,66,26,180,105,97,167,68,150,34,33,154,112,0,1,91,247,35,79,111,237,
198,174,232,47,31,23,95,17,13,31,249,96,211,49,50,53,214,77,141,24,0,0,181,
10,228,240,242,15,128,140,65,128,134,188,0,0,90,167,97,181,224,0,2,213,62,
53,224,0,2,213,66,237,120,0,0,181,81,204,107,192,0,5,170,150,67,94,0,0,45,
84,245,90,240,0,1,106,169,162,215,128,0,11,85,93,150,188,0,0,90,171,111,53,
109,22,162,26,48,0,1,84,23,201,146,243,225,26,39,12,145,136,104,192,0,5,61,
11,228,201,121,240,100,19,134,72,196,33,195,14,40,203,112,64,190,76,232,
145,153,136,0,0,31,15,224,0,0,0,25,152,0,0,30,15,224,0,0,0,25,120,144,13,
96,155,194,56,80,206,36,67,141,20,228,70,57,81,206,100,131,156,39,132,168,
23,194,70,46,137,208,21,200,129,166,39,9,24,186,39,72,119,34,66,146,36,104,
137,194,70,46,137,212,23,201,97,179,5,248,72,197,209,58,194,121,60,60,156,
36,98,232,157,129,29,164,80,78,198,46,137,218,146,121,25,71,146,9,209,5,
209,61,48,126,14,138,152,30,67,186,23,143,139,175,131,202,135,228,72,85,
144,83,60,179,30,94,209,233,102,30,98,105,230,103,30,114,121,231,104,30,
122,137,231,233,30,130,153,232,106,30,138,169,232,235,30,144,67,193,25,19,
136,108,207,30,41,224,140,137,194,173,192,153,228,5,242,100,188,248,70,137,
195,36,79,78,47,147,37,231,193,144,78,25,34,122,145,111,36,74,232,176,13,
17,61,234,226,93,207,148,160,84,75,141,7,27,161,32,33,18,225,80,212,76,154,
2,2,70,65,56,100,237,34,140,209,2,67,32,156,50,118,145,64,186,230,61,205,
35,103,155,32,36,141,19,134,78,210,40,206,16,36,70,137,195,39,105,20,11,
174,99,220,210,54,121,210,1,137,33,1,228,207,16,17,70,146,66,3,201,164,32,
0,65,112,152,56,196,159,31,23,77,211,195,201,199,23,160,72,214,246,81,6,12,
73,241,214,111,31,23,60,145,158,56,50,72,81,67,230,232,242,80,19,49,39,199,
89,188,124,92,242,70,120,227,64,194,75,154,72,12,9,73,6,111,21,120,12,40,
144,19,39,25,0,225,144,168,105,56,248,185,228,140,241,200,96,64,100,42,26,
78,62,46,121,35,52,18,92,116,1,36,64,47,158,64,49,98,66,100,156,242,65,23,
196,149,35,103,194,94,100,108,144,230,203,156,64,66,37,201,16,11,32,249,
132,4,34,92,44,93,146,55,152,72,24,137,112,151,153,27,36,5,100,229,144,8,
162,98,92,210,5,76,73,241,214,111,31,23,60,145,158,57,44,48,46,92,185,164,
160,72,151,41,0,50,107,179,244,59,36,93,127,92,6,19,172,3,11,216,0,56,224,
151,29,102,241,241,115,201,25,227,164,64,106,37,199,197,211,116,240,242,
113,197,233,144,40,248,185,228,140,241,196,75,132,109,24,72,128,43,39,84,
129,13,173,161,144,168,105,56,98,78,100,142,214,215,69,1,13,173,161,144,
168,105,57,34,78,100,142,214,215,69,16,67,107,105,110,114,168,254,24,147,
153,35,181,181,212,32,67,107,105,110,114,168,254,72,147,153,35,181,181,212,
36,65,130,3,144,8,26,252,200,13,30,85,16,16,64,90,242,231,192,64,161,163,
203,31,26,172,193,17,4,23,105,159,96,27,172,251,16,32,196,4,14,137,112,17,
136,48,164,28,134,80,215,202,1,132,130,8,12,39,52,64,155,31,24,56,36,1,189,
207,132,0,35,233,35,195,62,3,196,149,36,100,72,160,2,200,232,44,227,0,11,
37,160,68,142,128,36,157,25,200,32,26,79,90,4,73,43,192,122,54,71,65,103,
44,248,14,134,140,151,227,138,231,208,45,96,148,248,134,140,151,227,138,
231,240,1,255,254,10,74,146,56,128,104,4,147,152,72,6,144,28,174,143,8,1,
30,1,165,3,96,31,0,211,3,21,11,153,35,0,211,131,68,131,160,137,16,250,5,
196,131,160,137,200,160,199,156,67,248,0,255,255,65,140,10,48,177,115,56,
35,130,60,19,134,79,89,240,52,177,115,56,39,12,156,123,144,217,251,15,135,
34,167,30,20,170,154,255,232,12,47,244,0,97,28,17,224,39,238,32,40,71,4,
120,39,12,156,4,253,228,5,137,195,39,30,228,54,124,4,253,228,128,194,115,
68,9,252,15,128,232,104,201,126,56,191,35,64,90,193,41,241,13,25,47,199,23,
228,105,3,86,225,1,100,224,156,199,130,36,249,144,10,192,76,71,250,16,15,
18,61,96,17,62,200,3,72,128,136,143,247,32,22,75,64,137,248,64,22,79,90,39,
249,64,38,84,12,167,20,52,223,196,2,230,238,45,214,36,120,32,72,158,208,4,
102,238,45,194,2,201,197,186,196,143,4,9,19,218,0,92,221,202,61,228,143,4,
9,19,218,8,35,55,113,110,16,22,78,81,239,36,120,32,72,158,208,64,73,197,12,
255,0,13,18,60,128,159,212,128,169,76,17,156,185,100,76,255,163,64,65,26,
57,114,200,153,255,70,144,33,13,18,232,50,75,226,104,6,149,3,41,199,246,
130,12,128,28,142,156,120,203,175,158,8,194,207,1,6,81,20,79,88,11,237,84,
11,161,32,127,255,247,191,255,255,255,255,137,235,16,221,170,129,116,36,0,
0,0,0,0,16,0,0,12,196,0,0,15,135,240,0,0,0,2,61,123,164,137,162,164,218,67,
74,134,162,120,128,0,1,224,254,0,0,0,0,71,173,33,129,52,84,155,72,105,80,
212,79,16,0,0,60,63,192,0,0,0,3,244,143,146,22,230,192,0,0,176,60,0,0,0,0,
33,214,2,251,82,1,73,180,134,204,134,36,96,127,255,159,161,255,255,255,255,
144,235,16,221,169,0,164,218,67,102,67,18,48,63,255,207,240,255,255,255,
255,196,60,17,145,56,134,204,241,226,158,8,200,156,42,220,9,158,65,196,34,
92,42,26,137,147,120,64,74,37,196,54,100,49,35,188,36,5,68,184,208,113,187,
194,80,212,75,146,1,73,196,54,100,49,35,188,38,57,37,56,240,0,0,0,0,0,0,0,
0,32,235,248,68,48,156,2,24,94,24,0,243,119,10,139,144,123,242,3,102,238,
18,239,115,72,217,160,11,223,16,23,55,113,241,32,145,36,57,188,18,16,102,3,
5,120,35,34,89,32,15,180,152,173,127,0,218,235,88,0,228,180,227,200,0,0,
248,127,0,0,0,0,197,107,240,64,6,77,220,24,38,78,74,113,67,77,130,4,12,155,
185,52,48,156,148,226,134,155,4,10,194,96,129,132,166,238,45,194,2,201,193,
130,100,228,167,20,52,216,32,113,41,187,139,112,128,178,114,104,97,57,41,
197,13,54,8,32,48,216,32,130,195,224,130,19,97,124,134,23,6,0,57,137,62,77,
12,38,12,0,179,18,124,45,22,190,96,128,141,176,134,28,98,79,180,152,139,
218,45,124,193,1,27,97,16,32,196,159,24,230,204,246,194,40,89,137,62,210,
98,103,92,217,158,216,70,7,49,39,193,130,100,182,17,194,140,73,246,147,16,
250,9,146,216,72,6,49,39,193,131,22,194,72,73,137,62,210,98,31,65,139,97,
40,32,196,159,14,234,70,86,194,88,89,137,62,210,98,63,93,72,202,216,76,10,
49,39,198,33,180,153,37,108,38,134,152,147,237,38,38,117,13,164,201,43,97,
56,40,196,159,36,65,57,163,149,176,158,26,98,79,180,152,165,210,9,205,28,
173,133,0,243,18,124,98,22,180,72,130,115,71,43,97,68,72,196,159,105,49,51,
168,90,209,34,9,205,28,173,133,33,19,18,124,154,24,76,185,164,227,138,89,
18,119,0,7,145,39,201,161,132,188,64,124,137,62,49,11,90,36,65,57,163,149,
210,166,37,34,79,180,152,153,212,45,104,145,4,230,142,87,74,160,84,137,62,
72,130,115,71,43,171,234,134,200,147,237,38,41,116,130,115,71,43,171,235,5,
72,147,227,16,218,76,146,186,254,184,108,137,62,210,98,103,80,218,76,146,
186,254,192,68,137,62,29,212,140,174,207,178,23,34,79,180,152,143,215,82,
50,187,62,208,60,137,62,12,19,37,210,182,21,34,79,180,152,135,208,76,151,
74,224,68,137,62,49,205,153,238,175,186,23,34,79,180,152,153,215,54,103,
186,190,240,92,137,62,22,139,95,48,64,70,235,251,225,210,36,251,73,136,189,
162,215,204,16,17,186,255,2,14,98,79,152,32,35,108,48,64,242,36,249,130,2,
55,75,6,212,224,72,200,51,128,114,108,28,100,128,0,0,0,0,0,0,0,12,110,127,
48,98,115,249,201,117,243,249,195,21,159,206,38,47,63,156,86,8,75,144,94,
82,1,38,73,79,208,67,95,233,1,6,128,14,79,129,186,40,249,18,149,182,207,
144,200,155,188,248,204,105,184,207,142,199,137,175,201,0,159,72,10,5,21,
221,10,120,74,129,124,36,98,232,228,74,81,62,160,20,10,107,186,21,114,32,
105,137,194,70,46,142,68,165,19,235,1,64,170,187,161,119,34,66,146,36,104,
137,194,70,46,142,68,165,19,236,1,64,174,187,161,95,37,134,204,23,225,35,
23,71,34,82,137,246,128,160,89,93,208,167,147,195,201,194,70,46,142,68,165,
19,238,1,64,182,187,161,71,105,20,19,177,139,163,145,41,68,16,7,6,15,82,70,
72,115,96,0,2,234,32,0,0,0,0,91,60,165,195,201,194,8,134,149,216,162,0,192,
41,225,8,2,48,177,36,1,149,13,196,15,0,200,209,97,199,128,99,32,176,195,
192,113,57,143,0,167,133,32,230,80,28,202,139,175,238,2,48,189,192,20,1,
119,80,87,193,186,129,89,56,72,197,209,200,193,185,35,23,71,109,13,219,36,
98,232,237,156,13,26,208,211,14,102,19,87,137,91,95,128,0,10,96,24,92,0,0,
83,2,53,56,0,0,165,3,28,204,160,160,226,100,226,200,211,76,241,240,0,1,102,
8,22,75,64,137,73,20,230,105,133,7,19,39,22,70,154,103,143,128,0,11,48,20,
28,76,156,113,75,34,78,62,0,0,45,3,103,31,0,0,22,65,44,57,137,62,33,179,
216,162,152,192,131,18,124,162,27,61,138,41,108,32,196,159,16,217,232,235,
81,76,104,73,137,62,81,13,158,142,181,20,184,16,98,79,136,108,244,244,168,
166,56,36,196,159,40,134,207,79,74,138,93,10,49,39,194,173,192,158,158,149,
20,188,20,98,79,133,91,129,61,109,74,41,124,30,68,159,16,217,236,83,108,96,
68,137,62,81,13,158,197,54,182,17,34,79,136,108,244,117,169,182,52,38,68,
159,40,134,207,71,90,155,92,8,145,39,196,54,122,122,84,219,28,19,34,79,148,
67,103,167,165,77,174,133,72,147,225,86,224,79,79,74,155,94,10,145,39,194,
173,192,158,182,165,54,190,206,25,212,35,208,226,100,150,211,201,29,162,44,
140,35,103,0,0,3,192,252,0,0,0,0,206,25,228,35,208,226,100,150,211,201,29,
162,44,140,35,103,0,0,3,192,252,0,0,0,0,206,25,244,35,208,226,100,150,211,
201,29,162,44,140,35,103,0,0,3,192,252,0,0,0,0,206,26,4,35,208,226,100,150,
211,201,29,162,44,140,35,103,0,0,0,1,0,0,0,0,0,206,26,20,35,208,226,100,
150,211,201,29,162,44,140,35,103,0,0,0,1,0,0,0,0,0,206,26,36,35,208,226,
100,150,211,201,29,162,44,140,35,103,0,0,0,65,0,0,0,0,0,206,26,52,35,208,
226,100,150,211,201,29,162,44,140,35,103,0,0,0,65,0,0,0,0,0,206,26,68,35,
208,226,100,150,211,201,29,162,44,140,35,103,0,0,0,65,0,0,0,0,0,206,26,84,
35,208,226,100,150,211,201,29,162,44,140,35,103,0,0,0,129,0,0,0,0,0,195,
154,99,16,38,36,0,251,68,117,179,216,162,128,68,72,1,241,13,158,197,20,150,
25,18,0,125,162,58,217,232,235,117,100,162,136,25,18,0,125,162,58,217,232,
235,116,36,162,145,2,226,64,15,136,108,244,117,186,178,81,73,129,113,32,7,
196,54,122,58,221,9,40,165,64,200,144,3,237,17,214,207,79,75,171,37,20,80,
200,144,3,237,17,214,207,79,75,161,37,20,138,23,18,0,124,67,103,167,165,
213,146,138,77,11,137,0,62,33,179,211,210,232,73,69,42,133,196,128,31,10,
183,2,125,89,40,163,5,196,128,31,10,183,2,125,9,40,164,96,200,144,3,224,
221,64,172,157,89,40,163,134,68,128,31,6,234,5,100,232,73,69,35,133,68,128,
31,104,142,182,125,89,40,180,0,168,144,3,237,17,214,207,161,37,22,144,19,
18,0,124,67,103,213,146,139,80,9,137,0,62,33,179,232,73,69,172,5,90,40,153,
59,68,117,179,216,166,192,77,162,137,147,136,108,246,41,180,176,219,69,19,
39,104,142,182,122,58,221,89,41,178,6,218,40,153,59,68,117,179,209,214,232,
73,77,162,6,90,40,153,56,134,207,71,91,171,37,54,152,25,104,162,100,226,27,
61,29,110,132,148,218,160,109,162,137,147,180,71,91,61,61,46,172,148,217,
67,109,20,76,157,162,58,217,233,233,116,36,166,209,67,45,20,76,156,67,103,
167,165,213,146,155,77,12,180,81,50,113,13,158,158,151,66,74,109,84,50,209,
68,201,194,173,192,159,86,74,108,193,150,138,38,78,21,110,4,250,18,83,104,
193,182,138,38,78,13,212,10,201,213,146,155,56,109,162,137,147,131,117,2,
178,116,36,166,209,194,237,20,76,157,162,58,217,245,100,167,16,2,237,20,76,
157,162,58,217,244,36,167,18,2,173,20,76,156,67,103,213,146,156,80,10,180,
81,50,113,13,159,66,74,113,97,175,221,48,216,110,64,4,42,22,189,179,0,196,
133,0,185,80,32,28,78,99,193,18,80,36,4,19,159,141,172,0,178,90,4,74,73,0,
22,209,68,201,187,129,4,2,8,3,132,64,60,36,0,171,240,84,6,149,113,72,176,
157,91,116,116,32,88,181,129,32,11,42,218,221,131,234,219,165,1,8,187,152,
255,188,231,235,248,47,86,227,105,18,2,56,175,185,255,244,17,91,40,110,173,
198,209,208,36,7,188,189,179,240,238,82,97,80,93,122,32,125,144,132,160,12,
22,162,42,7,236,161,25,232,237,105,64,158,160,230,63,205,59,127,102,11,217,
66,51,210,129,61,65,236,127,154,118,254,205,171,197,34,168,48,6,90,194,1,0,
39,75,88,72,8,9,33,186,194,80,64,76,13,214,19,2,130,96,110,150,189,0,65,6,
51,214,20,128,65,17,11,214,19,130,137,121,211,210,211,144,6,39,75,88,80,0,
201,119,235,10,8,41,86,231,71,88,80,129,79,135,186,122,133,224,34,25,69,
234,80,3,91,141,172,40,96,139,113,180,181,133,36,21,110,54,142,134,176,165,
1,176,23,213,47,0,216,134,234,215,128,111,117,181,232,128,209,3,70,230,107,
64,5,139,168,209,235,10,32,36,144,102,235,136,3,146,27,172,40,160,146,132,
103,172,40,192,115,3,117,133,28,22,113,163,69,172,41,103,1,66,188,17,145,
52,168,4,202,113,67,76,130,227,76,194,13,240,108,0,0,83,224,0,2,193,0,104,
146,84,97,48,0,1,94,192,56,169,24,145,179,192,0,5,112,8,56,16,32,128,56,18,
52,125,230,86,147,190,140,28,50,21,13,39,31,23,60,145,158,57,12,141,47,129,
6,155,194,188,24,49,39,199,89,188,124,92,242,70,120,224,201,33,69,15,155,
163,201,68,14,49,39,199,197,211,116,240,242,113,197,232,18,180,254,36,3,17,
46,18,243,35,100,128,172,156,178,70,163,154,76,34,248,146,164,108,248,75,
204,141,146,28,217,115,137,27,95,27,241,173,236,162,160,224,200,2,206,9,
113,13,148,192,209,18,22,164,146,37,193,57,162,4,249,39,196,128,24,2,178,
66,213,136,68,201,16,77,209,131,31,192,242,88,96,92,191,151,34,100,136,38,
232,255,252,92,221,199,197,12,68,209,82,66,212,11,155,185,41,197,13,55,38,
3,66,213,47,135,254,72,12,162,99,133,116,112,0,1,72,66,14,16,16,50,37,202,
160,150,154,66,14,20,8,57,192,28,24,80,113,50,113,100,105,166,120,248,0,0,
179,1,65,196,201,199,20,178,36,227,224,0,2,208,54,113,240,0,1,100,11,181,
192,0,5,178,1,18,160,65,24,131,20,145,25,188,48,132,122,28,76,146,218,121,
35,180,69,145,132,108,224,0,0,120,31,128,0,0,0,25,188,56,132,122,28,76,146,
218,121,35,180,69,145,132,108,224,0,0,120,31,128,0,0,0,40,160,45,110,23,30,
176,33,184,0,0,183,32,29,235,2,27,199,23,0,0,23,4,51,120,129,8,244,56,153,
37,180,242,71,104,139,35,8,217,192,0,0,240,63,0,0,0,0,51,120,145,8,244,56,
153,37,180,242,71,104,139,35,8,217,192,0,0,0,64,0,0,0,0,51,120,161,8,244,
56,153,37,180,242,71,104,139,35,8,217,192,0,0,0,64,0,0,0,0,51,120,177,8,
244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,16,64,0,0,0,0,51,120,193,
8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,16,64,0,0,0,0,51,120,
209,8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,16,64,0,0,0,0,51,
120,225,8,244,56,153,37,180,242,71,104,139,35,8,217,192,0,0,32,64,0,0,0,0,
32,227,194,0,97,57,162,4,246,104,5,34,92,35,68,225,161,166,220,16,16,137,
112,52,41,73,29,185,1,65,196,201,197,145,166,153,246,72,3,137,204,120,34,
74,8,199,1,67,17,162,112,201,84,128,97,144,78,25,42,16,131,169,1,205,66,8,
35,68,225,161,166,239,128,0,10,192,64,196,104,156,50,96,0,2,172,73,240,117,
96,57,170,97,4,104,156,52,52,221,240,0,1,82,1,74,9,129,125,240,0,1,82,32,
148,25,174,137,58,23,51,190,0,0,42,69,64,195,32,156,50,96,0,2,160,81,238,2,
3,107,173,218,3,192,
};
#else
#error invalid endianness defines
#endif
#endif  /* DUK_USE_ROM_OBJECTS */

/* automatic undefs */
#undef DUK__REFCINIT
/*
 *  Error and fatal handling.
 */

/* #include duk_internal.h -> already included */

#define DUK__ERRFMT_BUFSIZE  256  /* size for formatting buffers */

#if defined(DUK_USE_VERBOSE_ERRORS)

DUK_INTERNAL DUK_COLD void duk_err_handle_error_fmt(duk_hthread *thr, const char *filename, duk_uint_t line_and_code, const char *fmt, ...) {
	va_list ap;
	char msg[DUK__ERRFMT_BUFSIZE];
	va_start(ap, fmt);
	(void) DUK_VSNPRINTF(msg, sizeof(msg), fmt, ap);
	msg[sizeof(msg) - 1] = (char) 0;
	duk_err_create_and_throw(thr, (duk_errcode_t) (line_and_code >> 24), msg, filename, (duk_int_t) (line_and_code & 0x00ffffffL));
	va_end(ap);  /* dead code, but ensures portability (see Linux man page notes) */
}

DUK_INTERNAL DUK_COLD void duk_err_handle_error(duk_hthread *thr, const char *filename, duk_uint_t line_and_code, const char *msg) {
	duk_err_create_and_throw(thr, (duk_errcode_t) (line_and_code >> 24), msg, filename, (duk_int_t) (line_and_code & 0x00ffffffL));
}

#else  /* DUK_USE_VERBOSE_ERRORS */

DUK_INTERNAL DUK_COLD void duk_err_handle_error(duk_hthread *thr, duk_errcode_t code) {
	duk_err_create_and_throw(thr, code);
}

#endif  /* DUK_USE_VERBOSE_ERRORS */

/*
 *  Error throwing helpers
 */

#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_INTERNAL DUK_COLD void duk_err_require_type_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx, const char *expect_name) {
	DUK_ERROR_RAW_FMT3(thr, filename, linenumber, DUK_ERR_TYPE_ERROR, "%s required, found %s (stack index %ld)",
	                   expect_name, duk_get_type_name(thr, idx), (long) idx);
}
#else
DUK_INTERNAL DUK_COLD void duk_err_require_type_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx, const char *expect_name) {
	DUK_ERROR_RAW_FMT3(thr, filename, linenumber, DUK_ERR_TYPE_ERROR, "%s required, found %s (stack index %ld)",
	                   expect_name, duk_push_string_readable(thr, idx), (long) idx);
}
#endif
DUK_INTERNAL DUK_COLD void duk_err_error_internal(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_ERROR, DUK_STR_INTERNAL_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_error_alloc_failed(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_ERROR, DUK_STR_ALLOC_FAILED);
}
DUK_INTERNAL DUK_COLD void duk_err_error(duk_hthread *thr, const char *filename, duk_int_t linenumber, const char *message) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_ERROR, message);
}
DUK_INTERNAL DUK_COLD void duk_err_range(duk_hthread *thr, const char *filename, duk_int_t linenumber, const char *message) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_RANGE_ERROR, message);
}
DUK_INTERNAL DUK_COLD void duk_err_range_index(duk_hthread *thr, const char *filename, duk_int_t linenumber, duk_idx_t idx) {
	DUK_ERROR_RAW_FMT1(thr, filename, linenumber, DUK_ERR_RANGE_ERROR, "invalid stack index %ld", (long) (idx));
}
DUK_INTERNAL DUK_COLD void duk_err_range_push_beyond(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_RANGE_ERROR, DUK_STR_PUSH_BEYOND_ALLOC_STACK);
}
DUK_INTERNAL DUK_COLD void duk_err_type_invalid_args(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_TYPE_ERROR, DUK_STR_INVALID_ARGS);
}
DUK_INTERNAL DUK_COLD void duk_err_type_invalid_state(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_TYPE_ERROR, DUK_STR_INVALID_STATE);
}
DUK_INTERNAL DUK_COLD void duk_err_type_invalid_trap_result(duk_hthread *thr, const char *filename, duk_int_t linenumber) {
	DUK_ERROR_RAW(thr, filename, linenumber, DUK_ERR_TYPE_ERROR, DUK_STR_INVALID_TRAP_RESULT);
}
#else
/* The file/line arguments are NULL and 0, they're ignored by DUK_ERROR_RAW()
 * when non-verbose errors are used.
 */

DUK_NORETURN(DUK_LOCAL_DECL void duk__err_shared(duk_hthread *thr, duk_errcode_t code));
DUK_LOCAL void duk__err_shared(duk_hthread *thr, duk_errcode_t code) {
	DUK_ERROR_RAW(thr, NULL, 0, code, NULL);
}
DUK_INTERNAL DUK_COLD void duk_err_error(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_range(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_RANGE_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_eval(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_EVAL_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_reference(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_REFERENCE_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_syntax(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_SYNTAX_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_type(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_TYPE_ERROR);
}
DUK_INTERNAL DUK_COLD void duk_err_uri(duk_hthread *thr) {
	duk__err_shared(thr, DUK_ERR_URI_ERROR);
}
#endif

/*
 *  Default fatal error handler
 */

DUK_INTERNAL DUK_COLD void duk_default_fatal_handler(void *udata, const char *msg) {
	DUK_UNREF(udata);
	DUK_UNREF(msg);

	msg = msg ? msg : "NULL";

#if defined(DUK_USE_FATAL_HANDLER)
	/* duk_config.h provided a custom default fatal handler. */
	DUK_D(DUK_DPRINT("custom default fatal error handler called: %s", msg));
	DUK_USE_FATAL_HANDLER(udata, msg);
#elif defined(DUK_USE_CPP_EXCEPTIONS)
	/* With C++ use a duk_fatal_exception which user code can catch in
	 * a natural way.
	 */
	DUK_D(DUK_DPRINT("built-in default C++ fatal error handler called: %s", msg));
	throw duk_fatal_exception(msg);
#else
	/* Default behavior is to abort() on error.  There's no printout
	 * which makes this awkward, so it's always recommended to use an
	 * explicit fatal error handler.
	 *
	 * ====================================================================
	 * NOTE: If you are seeing this, you are most likely dealing with an
	 * uncaught error.  You should provide a fatal error handler in Duktape
	 * heap creation, and should consider using a protected call as your
	 * first call into an empty Duktape context to properly handle errors.
	 * See:
	 *   - http://duktape.org/guide.html#error-handling
	 *   - http://wiki.duktape.org/HowtoFatalErrors.html
	 *   - http://duktape.org/api.html#taglist-protected
	 * ====================================================================
	 */
	DUK_D(DUK_DPRINT("built-in default fatal error handler called: %s", msg));
	DUK_ABORT();
#endif

	DUK_D(DUK_DPRINT("fatal error handler returned, enter forever loop"));
	for (;;) {
		/* Loop forever to ensure we don't return. */
	}
}

/* automatic undefs */
#undef DUK__ERRFMT_BUFSIZE
/*
 *  Various Unicode help functions for character classification predicates,
 *  case conversion, decoding, etc.
 */

/* #include duk_internal.h -> already included */

/*
 *  Fast path tables
 */

#if defined(DUK_USE_IDCHAR_FASTPATH)
DUK_INTERNAL const duk_int8_t duk_is_idchar_tab[128] = {
	/* 0: not IdentifierStart or IdentifierPart
	 * 1: IdentifierStart and IdentifierPart
	 * -1: IdentifierPart only
	 */
	0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,   /* 0x00...0x0f */
	0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,   /* 0x10...0x1f */
	0,  0,  0,  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,   /* 0x20...0x2f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0,  0,  0,  0,  0,  0,   /* 0x30...0x3f */
	0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,   /* 0x40...0x4f */
	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  0,  0,  0,  0,  1,   /* 0x50...0x5f */
	0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,   /* 0x60...0x6f */
	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  0,  0,  0,  0,  0    /* 0x70...0x7f */
};
#endif

/*
 *  XUTF-8 and CESU-8 encoding/decoding
 */

DUK_INTERNAL duk_small_int_t duk_unicode_get_xutf8_length(duk_ucodepoint_t cp) {
	duk_uint_fast32_t x = (duk_uint_fast32_t) cp;
	if (x < 0x80UL) {
		/* 7 bits */
		return 1;
	} else if (x < 0x800UL) {
		/* 11 bits */
		return 2;
	} else if (x < 0x10000UL) {
		/* 16 bits */
		return 3;
	} else if (x < 0x200000UL) {
		/* 21 bits */
		return 4;
	} else if (x < 0x4000000UL) {
		/* 26 bits */
		return 5;
	} else if (x < (duk_ucodepoint_t) 0x80000000UL) {
		/* 31 bits */
		return 6;
	} else {
		/* 36 bits */
		return 7;
	}
}

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL duk_small_int_t duk_unicode_get_cesu8_length(duk_ucodepoint_t cp) {
	duk_uint_fast32_t x = (duk_uint_fast32_t) cp;
	if (x < 0x80UL) {
		/* 7 bits */
		return 1;
	} else if (x < 0x800UL) {
		/* 11 bits */
		return 2;
	} else if (x < 0x10000UL) {
		/* 16 bits */
		return 3;
	} else {
		/* Encoded as surrogate pair, each encoding to 3 bytes for
		 * 6 bytes total.  Codepoints above U+10FFFF encode as 6 bytes
		 * too, see duk_unicode_encode_cesu8().
		  */
		return 3 + 3;
	}
}
#endif  /* DUK_USE_ASSERTIONS */

DUK_INTERNAL const duk_uint8_t duk_unicode_xutf8_markers[7] = {
	0x00, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe
};

/* Encode to extended UTF-8; 'out' must have space for at least
 * DUK_UNICODE_MAX_XUTF8_LENGTH bytes.  Allows encoding of any
 * 32-bit (unsigned) codepoint.
 */
DUK_INTERNAL duk_small_int_t duk_unicode_encode_xutf8(duk_ucodepoint_t cp, duk_uint8_t *out) {
	duk_uint_fast32_t x = (duk_uint_fast32_t) cp;
	duk_small_int_t len;
	duk_uint8_t marker;
	duk_small_int_t i;

	len = duk_unicode_get_xutf8_length(cp);
	DUK_ASSERT(len > 0);

	marker = duk_unicode_xutf8_markers[len - 1];  /* 64-bit OK because always >= 0 */

	i = len;
	DUK_ASSERT(i > 0);
	do {
		i--;
		if (i > 0) {
			out[i] = (duk_uint8_t) (0x80 + (x & 0x3f));
			x >>= 6;
		} else {
			/* Note: masking of 'x' is not necessary because of
			 * range check and shifting -> no bits overlapping
			 * the marker should be set.
			 */
			out[0] = (duk_uint8_t) (marker + x);
		}
	} while (i > 0);

	return len;
}

/* Encode to CESU-8; 'out' must have space for at least
 * DUK_UNICODE_MAX_CESU8_LENGTH bytes; codepoints above U+10FFFF
 * will encode to garbage but won't overwrite the output buffer.
 */
DUK_INTERNAL duk_small_int_t duk_unicode_encode_cesu8(duk_ucodepoint_t cp, duk_uint8_t *out) {
	duk_uint_fast32_t x = (duk_uint_fast32_t) cp;
	duk_small_int_t len;

	if (x < 0x80UL) {
		out[0] = (duk_uint8_t) x;
		len = 1;
	} else if (x < 0x800UL) {
		out[0] = (duk_uint8_t) (0xc0 + ((x >> 6) & 0x1f));
		out[1] = (duk_uint8_t) (0x80 + (x & 0x3f));
		len = 2;
	} else if (x < 0x10000UL) {
		/* surrogate pairs get encoded here */
		out[0] = (duk_uint8_t) (0xe0 + ((x >> 12) & 0x0f));
		out[1] = (duk_uint8_t) (0x80 + ((x >> 6) & 0x3f));
		out[2] = (duk_uint8_t) (0x80 + (x & 0x3f));
		len = 3;
	} else {
		/*
		 *  Unicode codepoints above U+FFFF are encoded as surrogate
		 *  pairs here.  This ensures that all CESU-8 codepoints are
		 *  16-bit values as expected in ECMAScript.  The surrogate
		 *  pairs always get a 3-byte encoding (each) in CESU-8.
		 *  See: http://en.wikipedia.org/wiki/Surrogate_pair
		 *
		 *  20-bit codepoint, 10 bits (A and B) per surrogate pair:
		 *
		 *    x = 0b00000000 0000AAAA AAAAAABB BBBBBBBB
		 *  sp1 = 0b110110AA AAAAAAAA  (0xd800 + ((x >> 10) & 0x3ff))
		 *  sp2 = 0b110111BB BBBBBBBB  (0xdc00 + (x & 0x3ff))
		 *
		 *  Encoded into CESU-8:
		 *
		 *  sp1 -> 0b11101101  (0xe0 + ((sp1 >> 12) & 0x0f))
		 *      -> 0b1010AAAA  (0x80 + ((sp1 >> 6) & 0x3f))
		 *      -> 0b10AAAAAA  (0x80 + (sp1 & 0x3f))
		 *  sp2 -> 0b11101101  (0xe0 + ((sp2 >> 12) & 0x0f))
		 *      -> 0b1011BBBB  (0x80 + ((sp2 >> 6) & 0x3f))
		 *      -> 0b10BBBBBB  (0x80 + (sp2 & 0x3f))
		 *
		 *  Note that 0x10000 must be subtracted first.  The code below
		 *  avoids the sp1, sp2 temporaries which saves around 20 bytes
		 *  of code.
		 */

		x -= 0x10000UL;

		out[0] = (duk_uint8_t) (0xed);
		out[1] = (duk_uint8_t) (0xa0 + ((x >> 16) & 0x0f));
		out[2] = (duk_uint8_t) (0x80 + ((x >> 10) & 0x3f));
		out[3] = (duk_uint8_t) (0xed);
		out[4] = (duk_uint8_t) (0xb0 + ((x >> 6) & 0x0f));
		out[5] = (duk_uint8_t) (0x80 + (x & 0x3f));
		len = 6;
	}

	return len;
}

/* Decode helper.  Return zero on error. */
DUK_INTERNAL duk_small_int_t duk_unicode_decode_xutf8(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end, duk_ucodepoint_t *out_cp) {
	const duk_uint8_t *p;
	duk_uint32_t res;
	duk_uint_fast8_t ch;
	duk_small_int_t n;

	DUK_UNREF(thr);

	p = *ptr;
	if (p < ptr_start || p >= ptr_end) {
		goto fail;
	}

	/*
	 *  UTF-8 decoder which accepts longer than standard byte sequences.
	 *  This allows full 32-bit code points to be used.
	 */

	ch = (duk_uint_fast8_t) (*p++);
	if (ch < 0x80) {
		/* 0xxx xxxx   [7 bits] */
		res = (duk_uint32_t) (ch & 0x7f);
		n = 0;
	} else if (ch < 0xc0) {
		/* 10xx xxxx -> invalid */
		goto fail;
	} else if (ch < 0xe0) {
		/* 110x xxxx   10xx xxxx   [11 bits] */
		res = (duk_uint32_t) (ch & 0x1f);
		n = 1;
	} else if (ch < 0xf0) {
		/* 1110 xxxx   10xx xxxx   10xx xxxx   [16 bits] */
		res = (duk_uint32_t) (ch & 0x0f);
		n = 2;
	} else if (ch < 0xf8) {
		/* 1111 0xxx   10xx xxxx   10xx xxxx   10xx xxxx   [21 bits] */
		res = (duk_uint32_t) (ch & 0x07);
		n = 3;
	} else if (ch < 0xfc) {
		/* 1111 10xx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   [26 bits] */
		res = (duk_uint32_t) (ch & 0x03);
		n = 4;
	} else if (ch < 0xfe) {
		/* 1111 110x   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   [31 bits] */
		res = (duk_uint32_t) (ch & 0x01);
		n = 5;
	} else if (ch < 0xff) {
		/* 1111 1110   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   [36 bits] */
		res = (duk_uint32_t) (0);
		n = 6;
	} else {
		/* 8-byte format could be:
		 * 1111 1111   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   10xx xxxx   [41 bits]
		 *
		 * However, this format would not have a zero bit following the
		 * leading one bits and would not allow 0xFF to be used as an
		 * "invalid xutf-8" marker for internal keys.  Further, 8-byte
		 * encodings (up to 41 bit code points) are not currently needed.
		 */
		goto fail;
	}

	DUK_ASSERT(p >= ptr_start);  /* verified at beginning */
	if (p + n > ptr_end) {
		/* check pointer at end */
		goto fail;
	}

	while (n > 0) {
		DUK_ASSERT(p >= ptr_start && p < ptr_end);
		ch = (duk_uint_fast8_t) (*p++);
#if 0
		if (ch & 0xc0 != 0x80) {
			/* not a continuation byte */
			p--;
			*ptr = p;
			*out_cp = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
			return 1;
		}
#endif
		res = (res << 6) + (duk_uint32_t) (ch & 0x3f);
		n--;
	}

	*ptr = p;
	*out_cp = res;
	return 1;

 fail:
	return 0;
}

/* used by e.g. duk_regexp_executor.c, string built-ins */
DUK_INTERNAL duk_ucodepoint_t duk_unicode_decode_xutf8_checked(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end) {
	duk_ucodepoint_t cp;

	if (duk_unicode_decode_xutf8(thr, ptr, ptr_start, ptr_end, &cp)) {
		return cp;
	}
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return 0;);
}

/* Compute (extended) utf-8 length without codepoint encoding validation,
 * used for string interning.
 *
 * NOTE: This algorithm is performance critical, more so than string hashing
 * in some cases.  It is needed when interning a string and needs to scan
 * every byte of the string with no skipping.  Having an ASCII fast path
 * is useful if possible in the algorithm.  The current algorithms were
 * chosen from several variants, based on x64 gcc -O2 testing.  See:
 * https://github.com/svaarala/duktape/pull/422
 *
 * NOTE: must match tools/dukutil.py:duk_unicode_unvalidated_utf8_length().
 */

#if defined(DUK_USE_PREFER_SIZE)
/* Small variant; roughly 150 bytes smaller than the fast variant. */
DUK_INTERNAL duk_size_t duk_unicode_unvalidated_utf8_length(const duk_uint8_t *data, duk_size_t blen) {
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	duk_size_t ncont;
	duk_size_t clen;

	p = data;
	p_end = data + blen;
	ncont = 0;
	while (p != p_end) {
		duk_uint8_t x;
		x = *p++;
		if (DUK_UNLIKELY(x >= 0x80 && x <= 0xbf)) {
			ncont++;
		}
	}

	DUK_ASSERT(ncont <= blen);
	clen = blen - ncont;
	DUK_ASSERT(clen <= blen);
	return clen;
}
#else  /* DUK_USE_PREFER_SIZE */
/* This seems like a good overall approach.  Fast path for ASCII in 4 byte
 * blocks.
 */
DUK_INTERNAL duk_size_t duk_unicode_unvalidated_utf8_length(const duk_uint8_t *data, duk_size_t blen) {
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	const duk_uint32_t *p32_end;
	const duk_uint32_t *p32;
	duk_size_t ncont;
	duk_size_t clen;

	ncont = 0;  /* number of continuation (non-initial) bytes in [0x80,0xbf] */
	p = data;
	p_end = data + blen;
	if (blen < 16) {
		goto skip_fastpath;
	}

	/* Align 'p' to 4; the input data may have arbitrary alignment.
	 * End of string check not needed because blen >= 16.
	 */
	while (((duk_size_t) (const void *) p) & 0x03U) {
		duk_uint8_t x;
		x = *p++;
		if (DUK_UNLIKELY(x >= 0x80 && x <= 0xbf)) {
			ncont++;
		}
	}

	/* Full, aligned 4-byte reads. */
	p32_end = (const duk_uint32_t *) (const void *) (p + ((duk_size_t) (p_end - p) & (duk_size_t) (~0x03)));
	p32 = (const duk_uint32_t *) (const void *) p;
	while (p32 != (const duk_uint32_t *) p32_end) {
		duk_uint32_t x;
		x = *p32++;
		if (DUK_LIKELY((x & 0x80808080UL) == 0)) {
			;  /* ASCII fast path */
		} else {
			/* Flip highest bit of each byte which changes
			 * the bit pattern 10xxxxxx into 00xxxxxx which
			 * allows an easy bit mask test.
			 */
			x ^= 0x80808080UL;
			if (DUK_UNLIKELY(!(x & 0xc0000000UL))) {
				ncont++;
			}
			if (DUK_UNLIKELY(!(x & 0x00c00000UL))) {
				ncont++;
			}
			if (DUK_UNLIKELY(!(x & 0x0000c000UL))) {
				ncont++;
			}
			if (DUK_UNLIKELY(!(x & 0x000000c0UL))) {
				ncont++;
			}
		}
	}
	p = (const duk_uint8_t *) p32;
	/* Fall through to handle the rest. */

 skip_fastpath:
	while (p != p_end) {
		duk_uint8_t x;
		x = *p++;
		if (DUK_UNLIKELY(x >= 0x80 && x <= 0xbf)) {
			ncont++;
		}
	}

	DUK_ASSERT(ncont <= blen);
	clen = blen - ncont;
	DUK_ASSERT(clen <= blen);
	return clen;
}
#endif  /* DUK_USE_PREFER_SIZE */

/* Check whether a string is UTF-8 compatible or not. */
DUK_INTERNAL duk_bool_t duk_unicode_is_utf8_compatible(const duk_uint8_t *buf, duk_size_t len) {
	duk_size_t i = 0;
#if !defined(DUK_USE_PREFER_SIZE)
	duk_size_t len_safe;
#endif

	/* Many practical strings are ASCII only, so use a fast path check
	 * to check chunks of bytes at once with minimal branch cost.
	 */
#if !defined(DUK_USE_PREFER_SIZE)
	len_safe = len & ~0x03UL;
	for (; i < len_safe; i += 4) {
		duk_uint8_t t = buf[i] | buf[i + 1] | buf[i + 2] | buf[i + 3];
		if (DUK_UNLIKELY((t & 0x80U) != 0U)) {
			/* At least one byte was outside 0x00-0x7f, break
			 * out to slow path (and remain there).
			 *
			 * XXX: We could also deal with the problem character
			 * and resume fast path later.
			 */
			break;
		}
	}
#endif

	for (; i < len;) {
		duk_uint8_t t;
		duk_size_t left;
		duk_size_t ncont;
		duk_uint32_t cp;
		duk_uint32_t mincp;

		t = buf[i++];
		if (DUK_LIKELY((t & 0x80U) == 0U)) {
			/* Fast path, ASCII. */
			continue;
		}

		/* Non-ASCII start byte, slow path.
		 *
		 * 10xx xxxx          -> continuation byte
		 * 110x xxxx + 1*CONT -> [0x80, 0x7ff]
		 * 1110 xxxx + 2*CONT -> [0x800, 0xffff], must reject [0xd800,0xdfff]
		 * 1111 0xxx + 3*CONT -> [0x10000, 0x10ffff]
		 */
		left = len - i;
		if (t <= 0xdfU) {  /* 1101 1111 = 0xdf */
			if (t <= 0xbfU) {  /* 1011 1111 = 0xbf */
				return 0;
			}
			ncont = 1;
			mincp = 0x80UL;
			cp = t & 0x1fU;
		} else if (t <= 0xefU) {  /* 1110 1111 = 0xef */
			ncont = 2;
			mincp = 0x800UL;
			cp = t & 0x0fU;
		} else if (t <= 0xf7U) {  /* 1111 0111 = 0xf7 */
			ncont = 3;
			mincp = 0x10000UL;
			cp = t & 0x07U;
		} else {
			return 0;
		}
		if (left < ncont) {
			return 0;
		}
		while (ncont > 0U) {
			t = buf[i++];
			if ((t & 0xc0U) != 0x80U) {  /* 10xx xxxx */
				return 0;
			}
			cp = (cp << 6) + (t & 0x3fU);
			ncont--;
		}
		if (cp < mincp || cp > 0x10ffffUL || (cp >= 0xd800UL && cp <= 0xdfffUL)) {
			return 0;
		}
	}

	return 1;
}

/*
 *  Unicode range matcher
 *
 *  Matches a codepoint against a packed bitstream of character ranges.
 *  Used for slow path Unicode matching.
 */

/* Must match tools/extract_chars.py, generate_match_table3(). */
DUK_LOCAL duk_uint32_t duk__uni_decode_value(duk_bitdecoder_ctx *bd_ctx) {
	duk_uint32_t t;

	t = (duk_uint32_t) duk_bd_decode(bd_ctx, 4);
	if (t <= 0x0eU) {
		return t;
	}
	t = (duk_uint32_t) duk_bd_decode(bd_ctx, 8);
	if (t <= 0xfdU) {
		return t + 0x0f;
	}
	if (t == 0xfeU) {
		t = (duk_uint32_t) duk_bd_decode(bd_ctx, 12);
		return t + 0x0fU + 0xfeU;
	} else {
		t = (duk_uint32_t) duk_bd_decode(bd_ctx, 24);
		return t + 0x0fU + 0xfeU + 0x1000UL;
	}
}

DUK_LOCAL duk_small_int_t duk__uni_range_match(const duk_uint8_t *unitab, duk_size_t unilen, duk_codepoint_t cp) {
	duk_bitdecoder_ctx bd_ctx;
	duk_codepoint_t prev_re;

	duk_memzero(&bd_ctx, sizeof(bd_ctx));
	bd_ctx.data = (const duk_uint8_t *) unitab;
	bd_ctx.length = (duk_size_t) unilen;

	prev_re = 0;
	for (;;) {
		duk_codepoint_t r1, r2;
		r1 = (duk_codepoint_t) duk__uni_decode_value(&bd_ctx);
		if (r1 == 0) {
			break;
		}
		r2 = (duk_codepoint_t) duk__uni_decode_value(&bd_ctx);

		r1 = prev_re + r1;
		r2 = r1 + r2;
		prev_re = r2;

		/* [r1,r2] is the range */

		DUK_DDD(DUK_DDDPRINT("duk__uni_range_match: cp=%06lx range=[0x%06lx,0x%06lx]",
		                     (unsigned long) cp, (unsigned long) r1, (unsigned long) r2));
		if (cp >= r1 && cp <= r2) {
			return 1;
		}
	}

	return 0;
}

/*
 *  "WhiteSpace" production check.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_is_whitespace(duk_codepoint_t cp) {
	/*
	 *  E5 Section 7.2 specifies six characters specifically as
	 *  white space:
	 *
	 *    0009;<control>;Cc;0;S;;;;;N;CHARACTER TABULATION;;;;
	 *    000B;<control>;Cc;0;S;;;;;N;LINE TABULATION;;;;
	 *    000C;<control>;Cc;0;WS;;;;;N;FORM FEED (FF);;;;
	 *    0020;SPACE;Zs;0;WS;;;;;N;;;;;
	 *    00A0;NO-BREAK SPACE;Zs;0;CS;<noBreak> 0020;;;;N;NON-BREAKING SPACE;;;;
	 *    FEFF;ZERO WIDTH NO-BREAK SPACE;Cf;0;BN;;;;;N;BYTE ORDER MARK;;;;
	 *
	 *  It also specifies any Unicode category 'Zs' characters as white
	 *  space.  These can be extracted with the "tools/extract_chars.py" script.
	 *  Current result:
	 *
	 *    RAW OUTPUT:
	 *    ===========
	 *    0020;SPACE;Zs;0;WS;;;;;N;;;;;
	 *    00A0;NO-BREAK SPACE;Zs;0;CS;<noBreak> 0020;;;;N;NON-BREAKING SPACE;;;;
	 *    1680;OGHAM SPACE MARK;Zs;0;WS;;;;;N;;;;;
	 *    180E;MONGOLIAN VOWEL SEPARATOR;Zs;0;WS;;;;;N;;;;;
	 *    2000;EN QUAD;Zs;0;WS;2002;;;;N;;;;;
	 *    2001;EM QUAD;Zs;0;WS;2003;;;;N;;;;;
	 *    2002;EN SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2003;EM SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2004;THREE-PER-EM SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2005;FOUR-PER-EM SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2006;SIX-PER-EM SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2007;FIGURE SPACE;Zs;0;WS;<noBreak> 0020;;;;N;;;;;
	 *    2008;PUNCTUATION SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    2009;THIN SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    200A;HAIR SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    202F;NARROW NO-BREAK SPACE;Zs;0;CS;<noBreak> 0020;;;;N;;;;;
	 *    205F;MEDIUM MATHEMATICAL SPACE;Zs;0;WS;<compat> 0020;;;;N;;;;;
	 *    3000;IDEOGRAPHIC SPACE;Zs;0;WS;<wide> 0020;;;;N;;;;;
	 *
	 *    RANGES:
	 *    =======
	 *    0x0020
	 *    0x00a0
	 *    0x1680
	 *    0x180e
	 *    0x2000 ... 0x200a
	 *    0x202f
	 *    0x205f
	 *    0x3000
	 *
	 *  A manual decoder (below) is probably most compact for this.
	 */

	duk_uint_fast8_t lo;
	duk_uint_fast32_t hi;

	/* cp == -1 (EOF) never matches and causes return value 0 */

	lo = (duk_uint_fast8_t) (cp & 0xff);
	hi = (duk_uint_fast32_t) (cp >> 8);  /* does not fit into an uchar */

	if (hi == 0x0000UL) {
		if (lo == 0x09U || lo == 0x0bU || lo == 0x0cU ||
		    lo == 0x20U || lo == 0xa0U) {
			return 1;
		}
	} else if (hi == 0x0020UL) {
		if (lo <= 0x0aU || lo == 0x2fU || lo == 0x5fU) {
			return 1;
		}
	} else if (cp == 0x1680L || cp == 0x180eL || cp == 0x3000L ||
	           cp == 0xfeffL) {
		return 1;
	}

	return 0;
}

/*
 *  "LineTerminator" production check.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_is_line_terminator(duk_codepoint_t cp) {
	/*
	 *  E5 Section 7.3
	 *
	 *  A LineTerminatorSequence essentially merges <CR> <LF> sequences
	 *  into a single line terminator.  This must be handled by the caller.
	 */

	if (cp == 0x000aL || cp == 0x000dL || cp == 0x2028L ||
	    cp == 0x2029L) {
		return 1;
	}

	return 0;
}

/*
 *  "IdentifierStart" production check.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_is_identifier_start(duk_codepoint_t cp) {
	/*
	 *  E5 Section 7.6:
	 *
	 *    IdentifierStart:
	 *      UnicodeLetter
	 *      $
	 *      _
	 *      \ UnicodeEscapeSequence
	 *
	 *  IdentifierStart production has one multi-character production:
	 *
	 *    \ UnicodeEscapeSequence
	 *
	 *  The '\' character is -not- matched by this function.  Rather, the caller
	 *  should decode the escape and then call this function to check whether the
	 *  decoded character is acceptable (see discussion in E5 Section 7.6).
	 *
	 *  The "UnicodeLetter" alternative of the production allows letters
	 *  from various Unicode categories.  These can be extracted with the
	 *  "tools/extract_chars.py" script.
	 *
	 *  Because the result has hundreds of Unicode codepoint ranges, matching
	 *  for any values >= 0x80 are done using a very slow range-by-range scan
	 *  and a packed range format.
	 *
	 *  The ASCII portion (codepoints 0x00 ... 0x7f) is fast-pathed below because
	 *  it matters the most.  The ASCII related ranges of IdentifierStart are:
	 *
	 *    0x0041 ... 0x005a     ['A' ... 'Z']
	 *    0x0061 ... 0x007a     ['a' ... 'z']
	 *    0x0024                ['$']
	 *    0x005f                ['_']
	 */

	/* ASCII (and EOF) fast path -- quick accept and reject */
	if (cp <= 0x7fL) {
#if defined(DUK_USE_IDCHAR_FASTPATH)
		return (cp >= 0) && (duk_is_idchar_tab[cp] > 0);
#else
		if ((cp >= 'a' && cp <= 'z') ||
		    (cp >= 'A' && cp <= 'Z') ||
		    cp == '_' || cp == '$') {
			return 1;
		}
		return 0;
#endif
	}

	/* Non-ASCII slow path (range-by-range linear comparison), very slow */

#if defined(DUK_USE_SOURCE_NONBMP)
	if (duk__uni_range_match(duk_unicode_ids_noa,
	                         (duk_size_t) sizeof(duk_unicode_ids_noa),
	                         (duk_codepoint_t) cp)) {
		return 1;
	}
	return 0;
#else
	if (cp < 0x10000L) {
		if (duk__uni_range_match(duk_unicode_ids_noabmp,
		                         sizeof(duk_unicode_ids_noabmp),
		                         (duk_codepoint_t) cp)) {
			return 1;
		}
		return 0;
	} else {
		/* without explicit non-BMP support, assume non-BMP characters
		 * are always accepted as identifier characters.
		 */
		return 1;
	}
#endif
}

/*
 *  "IdentifierPart" production check.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_is_identifier_part(duk_codepoint_t cp) {
	/*
	 *  E5 Section 7.6:
	 *
	 *    IdentifierPart:
	 *      IdentifierStart
	 *      UnicodeCombiningMark
	 *      UnicodeDigit
	 *      UnicodeConnectorPunctuation
	 *      <ZWNJ>  [U+200C]
	 *      <ZWJ>   [U+200D]
	 *
	 *  IdentifierPart production has one multi-character production
	 *  as part of its IdentifierStart alternative.  The '\' character
	 *  of an escape sequence is not matched here, see discussion in
	 *  duk_unicode_is_identifier_start().
	 *
	 *  To match non-ASCII characters (codepoints >= 0x80), a very slow
	 *  linear range-by-range scan is used.  The codepoint is first compared
	 *  to the IdentifierStart ranges, and if it doesn't match, then to a
	 *  set consisting of code points in IdentifierPart but not in
	 *  IdentifierStart.  This is done to keep the unicode range data small,
	 *  at the expense of speed.
	 *
	 *  The ASCII fast path consists of:
	 *
	 *    0x0030 ... 0x0039     ['0' ... '9', UnicodeDigit]
	 *    0x0041 ... 0x005a     ['A' ... 'Z', IdentifierStart]
	 *    0x0061 ... 0x007a     ['a' ... 'z', IdentifierStart]
	 *    0x0024                ['$', IdentifierStart]
	 *    0x005f                ['_', IdentifierStart and
	 *                                UnicodeConnectorPunctuation]
	 *
	 *  UnicodeCombiningMark has no code points <= 0x7f.
	 *
	 *  The matching code reuses the "identifier start" tables, and then
	 *  consults a separate range set for characters in "identifier part"
	 *  but not in "identifier start".  These can be extracted with the
	 *  "tools/extract_chars.py" script.
	 *
	 *  UnicodeCombiningMark -> categories Mn, Mc
	 *  UnicodeDigit -> categories Nd
	 *  UnicodeConnectorPunctuation -> categories Pc
	 */

	/* ASCII (and EOF) fast path -- quick accept and reject */
	if (cp <= 0x7fL) {
#if defined(DUK_USE_IDCHAR_FASTPATH)
		return (cp >= 0) && (duk_is_idchar_tab[cp] != 0);
#else
		if ((cp >= 'a' && cp <= 'z') ||
		    (cp >= 'A' && cp <= 'Z') ||
		    (cp >= '0' && cp <= '9') ||
		    cp == '_' || cp == '$') {
			return 1;
		}
		return 0;
#endif
	}

	/* Non-ASCII slow path (range-by-range linear comparison), very slow */

#if defined(DUK_USE_SOURCE_NONBMP)
	if (duk__uni_range_match(duk_unicode_ids_noa,
	                         sizeof(duk_unicode_ids_noa),
	                         (duk_codepoint_t) cp) ||
	    duk__uni_range_match(duk_unicode_idp_m_ids_noa,
	                         sizeof(duk_unicode_idp_m_ids_noa),
	                         (duk_codepoint_t) cp)) {
		return 1;
	}
	return 0;
#else
	if (cp < 0x10000L) {
		if (duk__uni_range_match(duk_unicode_ids_noabmp,
		                         sizeof(duk_unicode_ids_noabmp),
		                         (duk_codepoint_t) cp) ||
		    duk__uni_range_match(duk_unicode_idp_m_ids_noabmp,
		                         sizeof(duk_unicode_idp_m_ids_noabmp),
		                         (duk_codepoint_t) cp)) {
			return 1;
		}
		return 0;
	} else {
		/* without explicit non-BMP support, assume non-BMP characters
		 * are always accepted as identifier characters.
		 */
		return 1;
	}
#endif
}

/*
 *  Unicode letter check.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_is_letter(duk_codepoint_t cp) {
	/*
	 *  Unicode letter is now taken to be the categories:
	 *
	 *    Lu, Ll, Lt, Lm, Lo
	 *
	 *  (Not sure if this is exactly correct.)
	 *
	 *  The ASCII fast path consists of:
	 *
	 *    0x0041 ... 0x005a     ['A' ... 'Z']
	 *    0x0061 ... 0x007a     ['a' ... 'z']
	 */

	/* ASCII (and EOF) fast path -- quick accept and reject */
	if (cp <= 0x7fL) {
		if ((cp >= 'a' && cp <= 'z') ||
		    (cp >= 'A' && cp <= 'Z')) {
			return 1;
		}
		return 0;
	}

	/* Non-ASCII slow path (range-by-range linear comparison), very slow */

#if defined(DUK_USE_SOURCE_NONBMP)
	if (duk__uni_range_match(duk_unicode_ids_noa,
	                         sizeof(duk_unicode_ids_noa),
	                         (duk_codepoint_t) cp) &&
	    !duk__uni_range_match(duk_unicode_ids_m_let_noa,
	                          sizeof(duk_unicode_ids_m_let_noa),
	                          (duk_codepoint_t) cp)) {
		return 1;
	}
	return 0;
#else
	if (cp < 0x10000L) {
		if (duk__uni_range_match(duk_unicode_ids_noabmp,
		                         sizeof(duk_unicode_ids_noabmp),
		                         (duk_codepoint_t) cp) &&
		    !duk__uni_range_match(duk_unicode_ids_m_let_noabmp,
		                          sizeof(duk_unicode_ids_m_let_noabmp),
		                          (duk_codepoint_t) cp)) {
			return 1;
		}
		return 0;
	} else {
		/* without explicit non-BMP support, assume non-BMP characters
		 * are always accepted as letters.
		 */
		return 1;
	}
#endif
}

/*
 *  Complex case conversion helper which decodes a bit-packed conversion
 *  control stream generated by tools/extract_caseconv.py.  The conversion
 *  is very slow because it runs through the conversion data in a linear
 *  fashion to save space (which is why ASCII characters have a special
 *  fast path before arriving here).
 *
 *  The particular bit counts etc have been determined experimentally to
 *  be small but still sufficient, and must match the Python script
 *  (tools/extract_caseconv.py).
 *
 *  The return value is the case converted codepoint or -1 if the conversion
 *  results in multiple characters (this is useful for regexp Canonicalization
 *  operation).  If 'buf' is not NULL, the result codepoint(s) are also
 *  appended to the hbuffer.
 *
 *  Context and locale specific rules must be checked before consulting
 *  this function.
 */

DUK_LOCAL
duk_codepoint_t duk__slow_case_conversion(duk_hthread *thr,
                                          duk_bufwriter_ctx *bw,
                                          duk_codepoint_t cp,
                                          duk_bitdecoder_ctx *bd_ctx) {
	duk_small_int_t skip = 0;
	duk_small_int_t n;
	duk_small_int_t t;
	duk_small_int_t count;
	duk_codepoint_t tmp_cp;
	duk_codepoint_t start_i;
	duk_codepoint_t start_o;

	DUK_ASSERT(bd_ctx != NULL);
	DUK_UNREF(thr);

	DUK_DDD(DUK_DDDPRINT("slow case conversion for codepoint: %ld", (long) cp));

	/* range conversion with a "skip" */
	DUK_DDD(DUK_DDDPRINT("checking ranges"));
	for (;;) {
		skip++;
		n = (duk_small_int_t) duk_bd_decode(bd_ctx, 6);
		if (n == 0x3f) {
			/* end marker */
			break;
		}
		DUK_DDD(DUK_DDDPRINT("skip=%ld, n=%ld", (long) skip, (long) n));

		while (n--) {
			start_i = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
			start_o = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
			count = (duk_small_int_t) duk_bd_decode(bd_ctx, 7);
			DUK_DDD(DUK_DDDPRINT("range: start_i=%ld, start_o=%ld, count=%ld, skip=%ld",
			                     (long) start_i, (long) start_o, (long) count, (long) skip));

			if (cp >= start_i) {
				tmp_cp = cp - start_i;  /* always >= 0 */
				if (tmp_cp < (duk_codepoint_t) count * (duk_codepoint_t) skip &&
				    (tmp_cp % (duk_codepoint_t) skip) == 0) {
					DUK_DDD(DUK_DDDPRINT("range matches input codepoint"));
					cp = start_o + tmp_cp;
					goto single;
				}
			}
		}
	}

	/* 1:1 conversion */
	n = (duk_small_int_t) duk_bd_decode(bd_ctx, 7);
	DUK_DDD(DUK_DDDPRINT("checking 1:1 conversions (count %ld)", (long) n));
	while (n--) {
		start_i = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
		start_o = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
		DUK_DDD(DUK_DDDPRINT("1:1 conversion %ld -> %ld", (long) start_i, (long) start_o));
		if (cp == start_i) {
			DUK_DDD(DUK_DDDPRINT("1:1 matches input codepoint"));
			cp = start_o;
			goto single;
		}
	}

	/* complex, multicharacter conversion */
	n = (duk_small_int_t) duk_bd_decode(bd_ctx, 7);
	DUK_DDD(DUK_DDDPRINT("checking 1:n conversions (count %ld)", (long) n));
	while (n--) {
		start_i = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
		t = (duk_small_int_t) duk_bd_decode(bd_ctx, 2);
		DUK_DDD(DUK_DDDPRINT("1:n conversion %ld -> %ld chars", (long) start_i, (long) t));
		if (cp == start_i) {
			DUK_DDD(DUK_DDDPRINT("1:n matches input codepoint"));
			if (bw != NULL) {
				while (t--) {
					tmp_cp = (duk_codepoint_t) duk_bd_decode(bd_ctx, 16);
					DUK_BW_WRITE_RAW_XUTF8(thr, bw, (duk_ucodepoint_t) tmp_cp);
				}
			}
			return -1;
		} else {
			while (t--) {
				(void) duk_bd_decode(bd_ctx, 16);
			}
		}
	}

	/* default: no change */
	DUK_DDD(DUK_DDDPRINT("no rule matches, output is same as input"));
	/* fall through */

 single:
	if (bw != NULL) {
		DUK_BW_WRITE_RAW_XUTF8(thr, bw, (duk_ucodepoint_t) cp);
	}
	return cp;
}

/*
 *  Case conversion helper, with context/local sensitivity.
 *  For proper case conversion, one needs to know the character
 *  and the preceding and following characters, as well as
 *  locale/language.
 */

/* XXX: add 'language' argument when locale/language sensitive rule
 * support added.
 */
DUK_LOCAL
duk_codepoint_t duk__case_transform_helper(duk_hthread *thr,
                                           duk_bufwriter_ctx *bw,
                                           duk_codepoint_t cp,
                                           duk_codepoint_t prev,
                                           duk_codepoint_t next,
                                           duk_bool_t uppercase) {
	duk_bitdecoder_ctx bd_ctx;

	/* fast path for ASCII */
	if (cp < 0x80L) {
		/* XXX: there are language sensitive rules for the ASCII range.
		 * If/when language/locale support is implemented, they need to
		 * be implemented here for the fast path.  There are no context
		 * sensitive rules for ASCII range.
		 */

		if (uppercase) {
			if (cp >= 'a' && cp <= 'z') {
				cp = cp - 'a' + 'A';
			}
		} else {
			if (cp >= 'A' && cp <= 'Z') {
				cp = cp - 'A' + 'a';
			}
		}

		if (bw != NULL) {
			DUK_BW_WRITE_RAW_U8(thr, bw, (duk_uint8_t) cp);
		}
		return cp;
	}

	/* context and locale specific rules which cannot currently be represented
	 * in the caseconv bitstream: hardcoded rules in C
	 */
	if (uppercase) {
		/* XXX: turkish / azeri */
	} else {
		/*
		 *  Final sigma context specific rule.  This is a rather tricky
		 *  rule and this handling is probably not 100% correct now.
		 *  The rule is not locale/language specific so it is supported.
		 */

		if (cp == 0x03a3L &&    /* U+03A3 = GREEK CAPITAL LETTER SIGMA */
		    duk_unicode_is_letter(prev) &&        /* prev exists and is not a letter */
		    !duk_unicode_is_letter(next)) {       /* next does not exist or next is not a letter */
			/* Capital sigma occurred at "end of word", lowercase to
			 * U+03C2 = GREEK SMALL LETTER FINAL SIGMA.  Otherwise
			 * fall through and let the normal rules lowercase it to
			 * U+03C3 = GREEK SMALL LETTER SIGMA.
			 */
			cp = 0x03c2L;
			goto singlechar;
		}

		/* XXX: lithuanian not implemented */
		/* XXX: lithuanian, explicit dot rules */
		/* XXX: turkish / azeri, lowercase rules */
	}

	/* 1:1 or special conversions, but not locale/context specific: script generated rules */
	duk_memzero(&bd_ctx, sizeof(bd_ctx));
	if (uppercase) {
		bd_ctx.data = (const duk_uint8_t *) duk_unicode_caseconv_uc;
		bd_ctx.length = (duk_size_t) sizeof(duk_unicode_caseconv_uc);
	} else {
		bd_ctx.data = (const duk_uint8_t *) duk_unicode_caseconv_lc;
		bd_ctx.length = (duk_size_t) sizeof(duk_unicode_caseconv_lc);
	}
	return duk__slow_case_conversion(thr, bw, cp, &bd_ctx);

 singlechar:
	if (bw != NULL) {
		DUK_BW_WRITE_RAW_XUTF8(thr, bw, (duk_ucodepoint_t) cp);
	}
	return cp;

 /* unused now, not needed until Turkish/Azeri */
#if 0
 nochar:
	return -1;
#endif
}

/*
 *  Replace valstack top with case converted version.
 */

DUK_INTERNAL void duk_unicode_case_convert_string(duk_hthread *thr, duk_bool_t uppercase) {
	duk_hstring *h_input;
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
	const duk_uint8_t *p, *p_start, *p_end;
	duk_codepoint_t prev, curr, next;

	h_input = duk_require_hstring(thr, -1);  /* Accept symbols. */
	DUK_ASSERT(h_input != NULL);

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(thr, bw, DUK_HSTRING_GET_BYTELEN(h_input));

	/* [ ... input buffer ] */

	p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
	p = p_start;

	prev = -1; DUK_UNREF(prev);
	curr = -1;
	next = -1;
	for (;;) {
		prev = curr;
		curr = next;
		next = -1;
		if (p < p_end) {
			next = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p, p_start, p_end);
		} else {
			/* end of input and last char has been processed */
			if (curr < 0) {
				break;
			}
		}

		/* on first round, skip */
		if (curr >= 0) {
			/* XXX: could add a fast path to process chunks of input codepoints,
			 * but relative benefit would be quite small.
			 */

			/* Ensure space for maximum multi-character result; estimate is overkill. */
			DUK_BW_ENSURE(thr, bw, 8 * DUK_UNICODE_MAX_XUTF8_LENGTH);

			duk__case_transform_helper(thr,
			                           bw,
			                           (duk_codepoint_t) curr,
			                           prev,
			                           next,
			                           uppercase);
		}
	}

	DUK_BW_COMPACT(thr, bw);
	(void) duk_buffer_to_string(thr, -1);  /* Safe, output is encoded. */
	/* invalidates h_buf pointer */
	duk_remove_m2(thr);
}

#if defined(DUK_USE_REGEXP_SUPPORT)

/*
 *  Canonicalize() abstract operation needed for canonicalization of individual
 *  codepoints during regexp compilation and execution, see E5 Section 15.10.2.8.
 *  Note that codepoints are canonicalized one character at a time, so no context
 *  specific rules can apply.  Locale specific rules can apply, though.
 */

DUK_INTERNAL duk_codepoint_t duk_unicode_re_canonicalize_char(duk_hthread *thr, duk_codepoint_t cp) {
#if defined(DUK_USE_REGEXP_CANON_WORKAROUND)
	/* Fast canonicalization lookup at the cost of 128kB footprint. */
	DUK_ASSERT(cp >= 0);
	DUK_UNREF(thr);
	if (DUK_LIKELY(cp < 0x10000L)) {
		return (duk_codepoint_t) duk_unicode_re_canon_lookup[cp];
	}
	return cp;
#else  /* DUK_USE_REGEXP_CANON_WORKAROUND */
	duk_codepoint_t y;

	y = duk__case_transform_helper(thr,
	                               NULL,    /* NULL is allowed, no output */
	                               cp,      /* curr char */
	                               -1,      /* prev char */
	                               -1,      /* next char */
	                               1);      /* uppercase */

	if ((y < 0) || (cp >= 0x80 && y < 0x80)) {
		/* multiple codepoint conversion or non-ASCII mapped to ASCII
		 * --> leave as is.
		 */
		return cp;
	}

	return y;
#endif  /* DUK_USE_REGEXP_CANON_WORKAROUND */
}

/*
 *  E5 Section 15.10.2.6 "IsWordChar" abstract operation.  Assume
 *  x < 0 for characters read outside the string.
 */

DUK_INTERNAL duk_small_int_t duk_unicode_re_is_wordchar(duk_codepoint_t x) {
	/*
	 *  Note: the description in E5 Section 15.10.2.6 has a typo, it
	 *  contains 'A' twice and lacks 'a'; the intent is [0-9a-zA-Z_].
	 */
	if ((x >= '0' && x <= '9') ||
	    (x >= 'a' && x <= 'z') ||
	    (x >= 'A' && x <= 'Z') ||
	    (x == '_')) {
		return 1;
	}
	return 0;
}

/*
 *  Regexp range tables
 */

/* exposed because lexer needs these too */
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_digit[2] = {
	(duk_uint16_t) 0x0030UL, (duk_uint16_t) 0x0039UL,
};
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_white[22] = {
	(duk_uint16_t) 0x0009UL, (duk_uint16_t) 0x000DUL,
	(duk_uint16_t) 0x0020UL, (duk_uint16_t) 0x0020UL,
	(duk_uint16_t) 0x00A0UL, (duk_uint16_t) 0x00A0UL,
	(duk_uint16_t) 0x1680UL, (duk_uint16_t) 0x1680UL,
	(duk_uint16_t) 0x180EUL, (duk_uint16_t) 0x180EUL,
	(duk_uint16_t) 0x2000UL, (duk_uint16_t) 0x200AUL,
	(duk_uint16_t) 0x2028UL, (duk_uint16_t) 0x2029UL,
	(duk_uint16_t) 0x202FUL, (duk_uint16_t) 0x202FUL,
	(duk_uint16_t) 0x205FUL, (duk_uint16_t) 0x205FUL,
	(duk_uint16_t) 0x3000UL, (duk_uint16_t) 0x3000UL,
	(duk_uint16_t) 0xFEFFUL, (duk_uint16_t) 0xFEFFUL,
};
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_wordchar[8] = {
	(duk_uint16_t) 0x0030UL, (duk_uint16_t) 0x0039UL,
	(duk_uint16_t) 0x0041UL, (duk_uint16_t) 0x005AUL,
	(duk_uint16_t) 0x005FUL, (duk_uint16_t) 0x005FUL,
	(duk_uint16_t) 0x0061UL, (duk_uint16_t) 0x007AUL,
};
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_not_digit[4] = {
	(duk_uint16_t) 0x0000UL, (duk_uint16_t) 0x002FUL,
	(duk_uint16_t) 0x003AUL, (duk_uint16_t) 0xFFFFUL,
};
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_not_white[24] = {
	(duk_uint16_t) 0x0000UL, (duk_uint16_t) 0x0008UL,
	(duk_uint16_t) 0x000EUL, (duk_uint16_t) 0x001FUL,
	(duk_uint16_t) 0x0021UL, (duk_uint16_t) 0x009FUL,
	(duk_uint16_t) 0x00A1UL, (duk_uint16_t) 0x167FUL,
	(duk_uint16_t) 0x1681UL, (duk_uint16_t) 0x180DUL,
	(duk_uint16_t) 0x180FUL, (duk_uint16_t) 0x1FFFUL,
	(duk_uint16_t) 0x200BUL, (duk_uint16_t) 0x2027UL,
	(duk_uint16_t) 0x202AUL, (duk_uint16_t) 0x202EUL,
	(duk_uint16_t) 0x2030UL, (duk_uint16_t) 0x205EUL,
	(duk_uint16_t) 0x2060UL, (duk_uint16_t) 0x2FFFUL,
	(duk_uint16_t) 0x3001UL, (duk_uint16_t) 0xFEFEUL,
	(duk_uint16_t) 0xFF00UL, (duk_uint16_t) 0xFFFFUL,
};
DUK_INTERNAL const duk_uint16_t duk_unicode_re_ranges_not_wordchar[10] = {
	(duk_uint16_t) 0x0000UL, (duk_uint16_t) 0x002FUL,
	(duk_uint16_t) 0x003AUL, (duk_uint16_t) 0x0040UL,
	(duk_uint16_t) 0x005BUL, (duk_uint16_t) 0x005EUL,
	(duk_uint16_t) 0x0060UL, (duk_uint16_t) 0x0060UL,
	(duk_uint16_t) 0x007BUL, (duk_uint16_t) 0xFFFFUL,
};

#endif  /* DUK_USE_REGEXP_SUPPORT */
/*
 *  Macro support functions for reading/writing raw data.
 *
 *  These are done using memcpy to ensure they're valid even for unaligned
 *  reads/writes on platforms where alignment counts.  On x86 at least gcc
 *  is able to compile these into a bswap+mov.  "Always inline" is used to
 *  ensure these macros compile to minimal code.
 */

/* #include duk_internal.h -> already included */

union duk__u16_union {
	duk_uint8_t b[2];
	duk_uint16_t x;
};
typedef union duk__u16_union duk__u16_union;

union duk__u32_union {
	duk_uint8_t b[4];
	duk_uint32_t x;
};
typedef union duk__u32_union duk__u32_union;

#if defined(DUK_USE_64BIT_OPS)
union duk__u64_union {
	duk_uint8_t b[8];
	duk_uint64_t x;
};
typedef union duk__u64_union duk__u64_union;
#endif

DUK_INTERNAL DUK_ALWAYS_INLINE duk_uint16_t duk_raw_read_u16_be(const duk_uint8_t *p) {
	duk__u16_union u;
	duk_memcpy((void *) u.b, (const void *) p, (size_t) 2);
	u.x = DUK_NTOH16(u.x);
	return u.x;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_uint32_t duk_raw_read_u32_be(const duk_uint8_t *p) {
	duk__u32_union u;
	duk_memcpy((void *) u.b, (const void *) p, (size_t) 4);
	u.x = DUK_NTOH32(u.x);
	return u.x;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_float_t duk_raw_read_float_be(const duk_uint8_t *p) {
	duk_float_union fu;
	duk_memcpy((void *) fu.uc, (const void *) p, (size_t) 4);
	duk_fltunion_big_to_host(&fu);
	return fu.f;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_double_t duk_raw_read_double_be(const duk_uint8_t *p) {
	duk_double_union du;
	duk_memcpy((void *) du.uc, (const void *) p, (size_t) 8);
	duk_dblunion_big_to_host(&du);
	return du.d;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_uint16_t duk_raw_readinc_u16_be(const duk_uint8_t **p) {
	duk_uint16_t res = duk_raw_read_u16_be(*p);
	*p += 2;
	return res;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_uint32_t duk_raw_readinc_u32_be(const duk_uint8_t **p) {
	duk_uint32_t res = duk_raw_read_u32_be(*p);
	*p += 4;
	return res;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_float_t duk_raw_readinc_float_be(const duk_uint8_t **p) {
	duk_float_t res = duk_raw_read_float_be(*p);
	*p += 4;
	return res;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_double_t duk_raw_readinc_double_be(const duk_uint8_t **p) {
	duk_double_t res = duk_raw_read_double_be(*p);
	*p += 8;
	return res;
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_write_u16_be(duk_uint8_t *p, duk_uint16_t val) {
	duk__u16_union u;
	u.x = DUK_HTON16(val);
	duk_memcpy((void *) p, (const void *) u.b, (size_t) 2);
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_write_u32_be(duk_uint8_t *p, duk_uint32_t val) {
	duk__u32_union u;
	u.x = DUK_HTON32(val);
	duk_memcpy((void *) p, (const void *) u.b, (size_t) 4);
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_write_float_be(duk_uint8_t *p, duk_float_t val) {
	duk_float_union fu;
	fu.f = val;
	duk_fltunion_host_to_big(&fu);
	duk_memcpy((void *) p, (const void *) fu.uc, (size_t) 4);
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_write_double_be(duk_uint8_t *p, duk_double_t val) {
	duk_double_union du;
	du.d = val;
	duk_dblunion_host_to_big(&du);
	duk_memcpy((void *) p, (const void *) du.uc, (size_t) 8);
}

DUK_INTERNAL duk_small_int_t duk_raw_write_xutf8(duk_uint8_t *p, duk_ucodepoint_t val) {
	duk_small_int_t len = duk_unicode_encode_xutf8(val, p);
	return len;
}

DUK_INTERNAL duk_small_int_t duk_raw_write_cesu8(duk_uint8_t *p, duk_ucodepoint_t val) {
	duk_small_int_t len = duk_unicode_encode_cesu8(val, p);
	return len;
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_writeinc_u16_be(duk_uint8_t **p, duk_uint16_t val) {
	duk_raw_write_u16_be(*p, val);
	*p += 2;
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_writeinc_u32_be(duk_uint8_t **p, duk_uint32_t val) {
	duk_raw_write_u32_be(*p, val);
	*p += 4;
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_writeinc_float_be(duk_uint8_t **p, duk_float_t val) {
	duk_raw_write_float_be(*p, val);
	*p += 4;
}

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_raw_writeinc_double_be(duk_uint8_t **p, duk_double_t val) {
	duk_raw_write_double_be(*p, val);
	*p += 8;
}

DUK_INTERNAL void duk_raw_writeinc_xutf8(duk_uint8_t **p, duk_ucodepoint_t val) {
	duk_small_int_t len = duk_unicode_encode_xutf8(val, *p);
	*p += len;
}

DUK_INTERNAL void duk_raw_writeinc_cesu8(duk_uint8_t **p, duk_ucodepoint_t val) {
	duk_small_int_t len = duk_unicode_encode_cesu8(val, *p);
	*p += len;
}
/*
 *  Misc util stuff.
 */

/* #include duk_internal.h -> already included */

/*
 *  Lowercase digits for radix values 2 to 36.  Also doubles as lowercase
 *  hex nybble table.
 */

DUK_INTERNAL const duk_uint8_t duk_lc_digits[36] = {
	DUK_ASC_0, DUK_ASC_1, DUK_ASC_2, DUK_ASC_3,
	DUK_ASC_4, DUK_ASC_5, DUK_ASC_6, DUK_ASC_7,
	DUK_ASC_8, DUK_ASC_9, DUK_ASC_LC_A, DUK_ASC_LC_B,
	DUK_ASC_LC_C, DUK_ASC_LC_D, DUK_ASC_LC_E, DUK_ASC_LC_F,
	DUK_ASC_LC_G, DUK_ASC_LC_H, DUK_ASC_LC_I, DUK_ASC_LC_J,
	DUK_ASC_LC_K, DUK_ASC_LC_L, DUK_ASC_LC_M, DUK_ASC_LC_N,
	DUK_ASC_LC_O, DUK_ASC_LC_P, DUK_ASC_LC_Q, DUK_ASC_LC_R,
	DUK_ASC_LC_S, DUK_ASC_LC_T, DUK_ASC_LC_U, DUK_ASC_LC_V,
	DUK_ASC_LC_W, DUK_ASC_LC_X, DUK_ASC_LC_Y, DUK_ASC_LC_Z
};

DUK_INTERNAL const duk_uint8_t duk_uc_nybbles[16] = {
	DUK_ASC_0, DUK_ASC_1, DUK_ASC_2, DUK_ASC_3,
	DUK_ASC_4, DUK_ASC_5, DUK_ASC_6, DUK_ASC_7,
	DUK_ASC_8, DUK_ASC_9, DUK_ASC_UC_A, DUK_ASC_UC_B,
	DUK_ASC_UC_C, DUK_ASC_UC_D, DUK_ASC_UC_E, DUK_ASC_UC_F
};

/*
 *  Table for hex decoding ASCII hex digits
 */

DUK_INTERNAL const duk_int8_t duk_hex_dectab[256] = {
	/* -1 if invalid */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x00-0x0f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x10-0x1f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x20-0x2f */
	 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,  /* 0x30-0x3f */
	-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x40-0x4f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x50-0x5f */
	-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x60-0x6f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x70-0x7f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x80-0x8f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x90-0x9f */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0xa0-0xaf */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0xb0-0xbf */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0xc0-0xcf */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0xd0-0xdf */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0xe0-0xef */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1   /* 0xf0-0xff */
};

#if defined(DUK_USE_HEX_FASTPATH)
/* Preshifted << 4.  Must use 16-bit entry to allow negative value signaling. */
DUK_INTERNAL const duk_int16_t duk_hex_dectab_shift4[256] = {
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x00-0x0f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x10-0x1f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x20-0x2f */
	0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, 0x80, 0x90,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x30-0x3f */
	  -1, 0xa0, 0xb0, 0xc0, 0xd0, 0xe0, 0xf0,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x40-0x4f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x50-0x5f */
	  -1, 0xa0, 0xb0, 0xc0, 0xd0, 0xe0, 0xf0,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x60-0x6f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x70-0x7f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x80-0x8f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0x90-0x9f */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0xa0-0xaf */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0xb0-0xbf */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0xc0-0xcf */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0xd0-0xdf */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,  /* 0xe0-0xef */
	  -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1   /* 0xf0-0xff */
};
#endif

/*
 *  Table for hex encoding bytes
 */

#if defined(DUK_USE_HEX_FASTPATH)
/* Lookup to encode one byte directly into 2 characters:
 *
 *   def genhextab(bswap):
 *       for i in xrange(256):
 *           t = chr(i).encode('hex')
 *           if bswap:
 *               t = t[1] + t[0]
 *           print('0x' + t.encode('hex') + 'U')
 *   print('big endian'); genhextab(False)
 *   print('little endian'); genhextab(True)
*/
DUK_INTERNAL const duk_uint16_t duk_hex_enctab[256] = {
#if defined(DUK_USE_INTEGER_BE)
	0x3030U, 0x3031U, 0x3032U, 0x3033U, 0x3034U, 0x3035U, 0x3036U, 0x3037U,
	0x3038U, 0x3039U, 0x3061U, 0x3062U, 0x3063U, 0x3064U, 0x3065U, 0x3066U,
	0x3130U, 0x3131U, 0x3132U, 0x3133U, 0x3134U, 0x3135U, 0x3136U, 0x3137U,
	0x3138U, 0x3139U, 0x3161U, 0x3162U, 0x3163U, 0x3164U, 0x3165U, 0x3166U,
	0x3230U, 0x3231U, 0x3232U, 0x3233U, 0x3234U, 0x3235U, 0x3236U, 0x3237U,
	0x3238U, 0x3239U, 0x3261U, 0x3262U, 0x3263U, 0x3264U, 0x3265U, 0x3266U,
	0x3330U, 0x3331U, 0x3332U, 0x3333U, 0x3334U, 0x3335U, 0x3336U, 0x3337U,
	0x3338U, 0x3339U, 0x3361U, 0x3362U, 0x3363U, 0x3364U, 0x3365U, 0x3366U,
	0x3430U, 0x3431U, 0x3432U, 0x3433U, 0x3434U, 0x3435U, 0x3436U, 0x3437U,
	0x3438U, 0x3439U, 0x3461U, 0x3462U, 0x3463U, 0x3464U, 0x3465U, 0x3466U,
	0x3530U, 0x3531U, 0x3532U, 0x3533U, 0x3534U, 0x3535U, 0x3536U, 0x3537U,
	0x3538U, 0x3539U, 0x3561U, 0x3562U, 0x3563U, 0x3564U, 0x3565U, 0x3566U,
	0x3630U, 0x3631U, 0x3632U, 0x3633U, 0x3634U, 0x3635U, 0x3636U, 0x3637U,
	0x3638U, 0x3639U, 0x3661U, 0x3662U, 0x3663U, 0x3664U, 0x3665U, 0x3666U,
	0x3730U, 0x3731U, 0x3732U, 0x3733U, 0x3734U, 0x3735U, 0x3736U, 0x3737U,
	0x3738U, 0x3739U, 0x3761U, 0x3762U, 0x3763U, 0x3764U, 0x3765U, 0x3766U,
	0x3830U, 0x3831U, 0x3832U, 0x3833U, 0x3834U, 0x3835U, 0x3836U, 0x3837U,
	0x3838U, 0x3839U, 0x3861U, 0x3862U, 0x3863U, 0x3864U, 0x3865U, 0x3866U,
	0x3930U, 0x3931U, 0x3932U, 0x3933U, 0x3934U, 0x3935U, 0x3936U, 0x3937U,
	0x3938U, 0x3939U, 0x3961U, 0x3962U, 0x3963U, 0x3964U, 0x3965U, 0x3966U,
	0x6130U, 0x6131U, 0x6132U, 0x6133U, 0x6134U, 0x6135U, 0x6136U, 0x6137U,
	0x6138U, 0x6139U, 0x6161U, 0x6162U, 0x6163U, 0x6164U, 0x6165U, 0x6166U,
	0x6230U, 0x6231U, 0x6232U, 0x6233U, 0x6234U, 0x6235U, 0x6236U, 0x6237U,
	0x6238U, 0x6239U, 0x6261U, 0x6262U, 0x6263U, 0x6264U, 0x6265U, 0x6266U,
	0x6330U, 0x6331U, 0x6332U, 0x6333U, 0x6334U, 0x6335U, 0x6336U, 0x6337U,
	0x6338U, 0x6339U, 0x6361U, 0x6362U, 0x6363U, 0x6364U, 0x6365U, 0x6366U,
	0x6430U, 0x6431U, 0x6432U, 0x6433U, 0x6434U, 0x6435U, 0x6436U, 0x6437U,
	0x6438U, 0x6439U, 0x6461U, 0x6462U, 0x6463U, 0x6464U, 0x6465U, 0x6466U,
	0x6530U, 0x6531U, 0x6532U, 0x6533U, 0x6534U, 0x6535U, 0x6536U, 0x6537U,
	0x6538U, 0x6539U, 0x6561U, 0x6562U, 0x6563U, 0x6564U, 0x6565U, 0x6566U,
	0x6630U, 0x6631U, 0x6632U, 0x6633U, 0x6634U, 0x6635U, 0x6636U, 0x6637U,
	0x6638U, 0x6639U, 0x6661U, 0x6662U, 0x6663U, 0x6664U, 0x6665U, 0x6666U
#else  /* DUK_USE_INTEGER_BE */
	0x3030U, 0x3130U, 0x3230U, 0x3330U, 0x3430U, 0x3530U, 0x3630U, 0x3730U,
	0x3830U, 0x3930U, 0x6130U, 0x6230U, 0x6330U, 0x6430U, 0x6530U, 0x6630U,
	0x3031U, 0x3131U, 0x3231U, 0x3331U, 0x3431U, 0x3531U, 0x3631U, 0x3731U,
	0x3831U, 0x3931U, 0x6131U, 0x6231U, 0x6331U, 0x6431U, 0x6531U, 0x6631U,
	0x3032U, 0x3132U, 0x3232U, 0x3332U, 0x3432U, 0x3532U, 0x3632U, 0x3732U,
	0x3832U, 0x3932U, 0x6132U, 0x6232U, 0x6332U, 0x6432U, 0x6532U, 0x6632U,
	0x3033U, 0x3133U, 0x3233U, 0x3333U, 0x3433U, 0x3533U, 0x3633U, 0x3733U,
	0x3833U, 0x3933U, 0x6133U, 0x6233U, 0x6333U, 0x6433U, 0x6533U, 0x6633U,
	0x3034U, 0x3134U, 0x3234U, 0x3334U, 0x3434U, 0x3534U, 0x3634U, 0x3734U,
	0x3834U, 0x3934U, 0x6134U, 0x6234U, 0x6334U, 0x6434U, 0x6534U, 0x6634U,
	0x3035U, 0x3135U, 0x3235U, 0x3335U, 0x3435U, 0x3535U, 0x3635U, 0x3735U,
	0x3835U, 0x3935U, 0x6135U, 0x6235U, 0x6335U, 0x6435U, 0x6535U, 0x6635U,
	0x3036U, 0x3136U, 0x3236U, 0x3336U, 0x3436U, 0x3536U, 0x3636U, 0x3736U,
	0x3836U, 0x3936U, 0x6136U, 0x6236U, 0x6336U, 0x6436U, 0x6536U, 0x6636U,
	0x3037U, 0x3137U, 0x3237U, 0x3337U, 0x3437U, 0x3537U, 0x3637U, 0x3737U,
	0x3837U, 0x3937U, 0x6137U, 0x6237U, 0x6337U, 0x6437U, 0x6537U, 0x6637U,
	0x3038U, 0x3138U, 0x3238U, 0x3338U, 0x3438U, 0x3538U, 0x3638U, 0x3738U,
	0x3838U, 0x3938U, 0x6138U, 0x6238U, 0x6338U, 0x6438U, 0x6538U, 0x6638U,
	0x3039U, 0x3139U, 0x3239U, 0x3339U, 0x3439U, 0x3539U, 0x3639U, 0x3739U,
	0x3839U, 0x3939U, 0x6139U, 0x6239U, 0x6339U, 0x6439U, 0x6539U, 0x6639U,
	0x3061U, 0x3161U, 0x3261U, 0x3361U, 0x3461U, 0x3561U, 0x3661U, 0x3761U,
	0x3861U, 0x3961U, 0x6161U, 0x6261U, 0x6361U, 0x6461U, 0x6561U, 0x6661U,
	0x3062U, 0x3162U, 0x3262U, 0x3362U, 0x3462U, 0x3562U, 0x3662U, 0x3762U,
	0x3862U, 0x3962U, 0x6162U, 0x6262U, 0x6362U, 0x6462U, 0x6562U, 0x6662U,
	0x3063U, 0x3163U, 0x3263U, 0x3363U, 0x3463U, 0x3563U, 0x3663U, 0x3763U,
	0x3863U, 0x3963U, 0x6163U, 0x6263U, 0x6363U, 0x6463U, 0x6563U, 0x6663U,
	0x3064U, 0x3164U, 0x3264U, 0x3364U, 0x3464U, 0x3564U, 0x3664U, 0x3764U,
	0x3864U, 0x3964U, 0x6164U, 0x6264U, 0x6364U, 0x6464U, 0x6564U, 0x6664U,
	0x3065U, 0x3165U, 0x3265U, 0x3365U, 0x3465U, 0x3565U, 0x3665U, 0x3765U,
	0x3865U, 0x3965U, 0x6165U, 0x6265U, 0x6365U, 0x6465U, 0x6565U, 0x6665U,
	0x3066U, 0x3166U, 0x3266U, 0x3366U, 0x3466U, 0x3566U, 0x3666U, 0x3766U,
	0x3866U, 0x3966U, 0x6166U, 0x6266U, 0x6366U, 0x6466U, 0x6566U, 0x6666U
#endif  /* DUK_USE_INTEGER_BE */
};
#endif  /* DUK_USE_HEX_FASTPATH */

/*
 *  Arbitrary byteswap for potentially unaligned values
 *
 *  Used to byteswap pointers e.g. in debugger code.
 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)  /* For now only needed by the debugger. */
DUK_INTERNAL void duk_byteswap_bytes(duk_uint8_t *p, duk_small_uint_t len) {
	duk_uint8_t tmp;
	duk_uint8_t *q = p + len - 1;

	while (p - q < 0) {
		tmp = *p;
		*p = *q;
		*q = tmp;
		p++;
		q--;
	}
}
#endif
/*
 *  Hobject ECMAScript [[Class]].
 */

/* #include duk_internal.h -> already included */

#if (DUK_STRIDX_UC_ARGUMENTS > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_BOOLEAN > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_DATE > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_ERROR > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_FUNCTION > 255)
#error constant too large
#endif
#if (DUK_STRIDX_JSON > 255)
#error constant too large
#endif
#if (DUK_STRIDX_MATH > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_NUMBER > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_OBJECT > 255)
#error constant too large
#endif
#if (DUK_STRIDX_REG_EXP > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_STRING > 255)
#error constant too large
#endif
#if (DUK_STRIDX_GLOBAL > 255)
#error constant too large
#endif
#if (DUK_STRIDX_OBJ_ENV > 255)
#error constant too large
#endif
#if (DUK_STRIDX_DEC_ENV > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_POINTER > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UC_THREAD > 255)
#error constant too large
#endif
#if (DUK_STRIDX_ARRAY_BUFFER > 255)
#error constant too large
#endif
#if (DUK_STRIDX_DATA_VIEW > 255)
#error constant too large
#endif
#if (DUK_STRIDX_INT8_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UINT8_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UINT8_CLAMPED_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_INT16_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UINT16_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_INT32_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_UINT32_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_FLOAT32_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_FLOAT64_ARRAY > 255)
#error constant too large
#endif
#if (DUK_STRIDX_EMPTY_STRING > 255)
#error constant too large
#endif

/* Note: assumes that these string indexes are 8-bit, genstrings.py must ensure that */
DUK_INTERNAL duk_uint8_t duk_class_number_to_stridx[32] = {
	DUK_STRIDX_EMPTY_STRING,  /* NONE, intentionally empty */
	DUK_STRIDX_UC_OBJECT,
	DUK_STRIDX_UC_ARRAY,
	DUK_STRIDX_UC_FUNCTION,
	DUK_STRIDX_UC_ARGUMENTS,
	DUK_STRIDX_UC_BOOLEAN,
	DUK_STRIDX_UC_DATE,
	DUK_STRIDX_UC_ERROR,
	DUK_STRIDX_JSON,
	DUK_STRIDX_MATH,
	DUK_STRIDX_UC_NUMBER,
	DUK_STRIDX_REG_EXP,
	DUK_STRIDX_UC_STRING,
	DUK_STRIDX_GLOBAL,
	DUK_STRIDX_UC_SYMBOL,
	DUK_STRIDX_OBJ_ENV,
	DUK_STRIDX_DEC_ENV,
	DUK_STRIDX_UC_POINTER,
	DUK_STRIDX_UC_THREAD,
	DUK_STRIDX_ARRAY_BUFFER,
	DUK_STRIDX_DATA_VIEW,
	DUK_STRIDX_INT8_ARRAY,
	DUK_STRIDX_UINT8_ARRAY,
	DUK_STRIDX_UINT8_CLAMPED_ARRAY,
	DUK_STRIDX_INT16_ARRAY,
	DUK_STRIDX_UINT16_ARRAY,
	DUK_STRIDX_INT32_ARRAY,
	DUK_STRIDX_UINT32_ARRAY,
	DUK_STRIDX_FLOAT32_ARRAY,
	DUK_STRIDX_FLOAT64_ARRAY,
	DUK_STRIDX_EMPTY_STRING,  /* UNUSED, intentionally empty */
	DUK_STRIDX_EMPTY_STRING,  /* UNUSED, intentionally empty */
};
/*
 *  Default allocation functions.
 *
 *  Assumes behavior such as malloc allowing zero size, yielding
 *  a NULL or a unique pointer which is a no-op for free.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_PROVIDE_DEFAULT_ALLOC_FUNCTIONS)
DUK_INTERNAL void *duk_default_alloc_function(void *udata, duk_size_t size) {
	void *res;
	DUK_UNREF(udata);
	res = DUK_ANSI_MALLOC(size);
	DUK_DDD(DUK_DDDPRINT("default alloc function: %lu -> %p",
	                     (unsigned long) size, (void *) res));
	return res;
}

DUK_INTERNAL void *duk_default_realloc_function(void *udata, void *ptr, duk_size_t newsize) {
	void *res;
	DUK_UNREF(udata);
	res = DUK_ANSI_REALLOC(ptr, newsize);
	DUK_DDD(DUK_DDDPRINT("default realloc function: %p %lu -> %p",
	                     (void *) ptr, (unsigned long) newsize, (void *) res));
	return res;
}

DUK_INTERNAL void duk_default_free_function(void *udata, void *ptr) {
	DUK_DDD(DUK_DDDPRINT("default free function: %p", (void *) ptr));
	DUK_UNREF(udata);
	DUK_ANSI_FREE(ptr);
}
#endif  /* DUK_USE_PROVIDE_DEFAULT_ALLOC_FUNCTIONS */
/*
 *  Buffer
 */

/* #include duk_internal.h -> already included */

DUK_EXTERNAL void *duk_resize_buffer(duk_hthread *thr, duk_idx_t idx, duk_size_t new_size) {
	duk_hbuffer_dynamic *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hbuffer_dynamic *) duk_require_hbuffer(thr, idx);
	DUK_ASSERT(h != NULL);

	if (!(DUK_HBUFFER_HAS_DYNAMIC(h) && !DUK_HBUFFER_HAS_EXTERNAL(h))) {
		DUK_ERROR_TYPE(thr, DUK_STR_WRONG_BUFFER_TYPE);
		DUK_WO_NORETURN(return NULL;);
	}

	/* Maximum size check is handled by callee. */
	duk_hbuffer_resize(thr, h, new_size);

	return DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, h);
}

DUK_EXTERNAL void *duk_steal_buffer(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size) {
	duk_hbuffer_dynamic *h;
	void *ptr;
	duk_size_t sz;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hbuffer_dynamic *) duk_require_hbuffer(thr, idx);
	DUK_ASSERT(h != NULL);

	if (!(DUK_HBUFFER_HAS_DYNAMIC(h) && !DUK_HBUFFER_HAS_EXTERNAL(h))) {
		DUK_ERROR_TYPE(thr, DUK_STR_WRONG_BUFFER_TYPE);
		DUK_WO_NORETURN(return NULL;);
	}

	/* Forget the previous allocation, setting size to 0 and alloc to
	 * NULL.  Caller is responsible for freeing the previous allocation.
	 * Getting the allocation and clearing it is done in the same API
	 * call to avoid any chance of a realloc.
	 */
	ptr = DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, h);
	sz = DUK_HBUFFER_DYNAMIC_GET_SIZE(h);
	if (out_size) {
		*out_size = sz;
	}
	DUK_HBUFFER_DYNAMIC_SET_DATA_PTR_NULL(thr->heap, h);
	DUK_HBUFFER_DYNAMIC_SET_SIZE(h, 0);

	return ptr;
}

DUK_EXTERNAL void duk_config_buffer(duk_hthread *thr, duk_idx_t idx, void *ptr, duk_size_t len) {
	duk_hbuffer_external *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hbuffer_external *) duk_require_hbuffer(thr, idx);
	DUK_ASSERT(h != NULL);

	if (!DUK_HBUFFER_HAS_EXTERNAL(h)) {
		DUK_ERROR_TYPE(thr, DUK_STR_WRONG_BUFFER_TYPE);
		DUK_WO_NORETURN(return;);
	}
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(h));

	DUK_HBUFFER_EXTERNAL_SET_DATA_PTR(thr->heap, h, ptr);
	DUK_HBUFFER_EXTERNAL_SET_SIZE(h, len);
}
/*
 *  Bytecode dump/load
 *
 *  The bytecode load primitive is more important performance-wise than the
 *  dump primitive.
 *
 *  Unlike most Duktape API calls, bytecode dump/load is not guaranteed to be
 *  memory safe for invalid arguments - caller beware!  There's little point
 *  in trying to achieve memory safety unless bytecode instructions are also
 *  validated which is not easy to do with indirect register references etc.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_BYTECODE_DUMP_SUPPORT)

#define DUK__SER_MARKER  0xbf
#define DUK__SER_STRING  0x00
#define DUK__SER_NUMBER  0x01
#define DUK__BYTECODE_INITIAL_ALLOC 256
#define DUK__NO_FORMALS  0xffffffffUL

/*
 *  Dump/load helpers, xxx_raw() helpers do no buffer checks
 */

DUK_LOCAL const duk_uint8_t *duk__load_string_raw(duk_hthread *thr, const duk_uint8_t *p) {
	duk_uint32_t len;

	len = DUK_RAW_READINC_U32_BE(p);
	duk_push_lstring(thr, (const char *) p, len);
	p += len;
	return p;
}

DUK_LOCAL const duk_uint8_t *duk__load_buffer_raw(duk_hthread *thr, const duk_uint8_t *p) {
	duk_uint32_t len;
	duk_uint8_t *buf;

	len = DUK_RAW_READINC_U32_BE(p);
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, (duk_size_t) len);
	DUK_ASSERT(buf != NULL);
	duk_memcpy((void *) buf, (const void *) p, (size_t) len);
	p += len;
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_hstring_raw(duk_uint8_t *p, duk_hstring *h) {
	duk_size_t len;
	duk_uint32_t tmp32;

	DUK_ASSERT(h != NULL);

	len = DUK_HSTRING_GET_BYTELEN(h);
	DUK_ASSERT(len <= 0xffffffffUL);  /* string limits */
	tmp32 = (duk_uint32_t) len;
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	duk_memcpy((void *) p,
	           (const void *) DUK_HSTRING_GET_DATA(h),
	           len);
	p += len;
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_hbuffer_raw(duk_hthread *thr, duk_uint8_t *p, duk_hbuffer *h) {
	duk_size_t len;
	duk_uint32_t tmp32;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	DUK_UNREF(thr);

	len = DUK_HBUFFER_GET_SIZE(h);
	DUK_ASSERT(len <= 0xffffffffUL);  /* buffer limits */
	tmp32 = (duk_uint32_t) len;
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	/* When len == 0, buffer data pointer may be NULL. */
	duk_memcpy_unsafe((void *) p,
	                  (const void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h),
	                  len);
	p += len;
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_string_prop(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func, duk_small_uint_t stridx) {
	duk_hstring *h_str;
	duk_tval *tv;

	tv = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, (duk_hobject *) func, stridx);
	if (tv != NULL && DUK_TVAL_IS_STRING(tv)) {
		h_str = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h_str != NULL);
	} else {
		h_str = DUK_HTHREAD_STRING_EMPTY_STRING(thr);
		DUK_ASSERT(h_str != NULL);
	}
	DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
	p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U + DUK_HSTRING_GET_BYTELEN(h_str), p);
	p = duk__dump_hstring_raw(p, h_str);
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_buffer_prop(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func, duk_small_uint_t stridx) {
	duk_tval *tv;

	tv = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, (duk_hobject *) func, stridx);
	if (tv != NULL && DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h_buf;
		h_buf = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h_buf != NULL);
		DUK_ASSERT(DUK_HBUFFER_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U + DUK_HBUFFER_GET_SIZE(h_buf), p);
		p = duk__dump_hbuffer_raw(thr, p, h_buf);
	} else {
		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U, p);
		DUK_RAW_WRITEINC_U32_BE(p, 0);
	}
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_uint32_prop(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func, duk_small_uint_t stridx, duk_uint32_t def_value) {
	duk_tval *tv;
	duk_uint32_t val;

	tv = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, (duk_hobject *) func, stridx);
	if (tv != NULL && DUK_TVAL_IS_NUMBER(tv)) {
		val = (duk_uint32_t) DUK_TVAL_GET_NUMBER(tv);
	} else {
		val = def_value;
	}
	p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U, p);
	DUK_RAW_WRITEINC_U32_BE(p, val);
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_varmap(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func) {
	duk_hobject *h;

	h = duk_hobject_get_varmap(thr, (duk_hobject *) func);
	if (h != NULL) {
		duk_uint_fast32_t i;

		/* We know _Varmap only has own properties so walk property
		 * table directly.  We also know _Varmap is dense and all
		 * values are numbers; assert for these.  GC and finalizers
		 * shouldn't affect _Varmap so side effects should be fine.
		 */
		for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
			duk_hstring *key;
			duk_tval *tv_val;
			duk_uint32_t val;

			key = DUK_HOBJECT_E_GET_KEY(thr->heap, h, i);
			DUK_ASSERT(key != NULL);  /* _Varmap is dense */
			DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h, i));
			tv_val = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h, i);
			DUK_ASSERT(tv_val != NULL);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_val));  /* known to be number; in fact an integer */
#if defined(DUK_USE_FASTINT)
			DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv_val));
			DUK_ASSERT(DUK_TVAL_GET_FASTINT(tv_val) == (duk_int64_t) DUK_TVAL_GET_FASTINT_U32(tv_val));  /* known to be 32-bit */
			val = DUK_TVAL_GET_FASTINT_U32(tv_val);
#else
			val = (duk_uint32_t) DUK_TVAL_GET_NUMBER(tv_val);
#endif

			DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
			p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U + DUK_HSTRING_GET_BYTELEN(key) + 4U, p);
			p = duk__dump_hstring_raw(p, key);
			DUK_RAW_WRITEINC_U32_BE(p, val);
		}
	}
	p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U, p);
	DUK_RAW_WRITEINC_U32_BE(p, 0);  /* end of _Varmap */
	return p;
}

DUK_LOCAL duk_uint8_t *duk__dump_formals(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func) {
	duk_harray *h;

	h = duk_hobject_get_formals(thr, (duk_hobject *) func);
	if (h != NULL) {
		duk_uint32_t i;

		/* Here we rely on _Formals being a dense array containing
		 * strings.  This should be the case unless _Formals has been
		 * tweaked by the application (which we don't support right
		 * now).
		 */

		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U, p);
		DUK_ASSERT(h->length != DUK__NO_FORMALS);  /* limits */
		DUK_RAW_WRITEINC_U32_BE(p, h->length);

		for (i = 0; i < h->length; i++) {
			duk_tval *tv_val;
			duk_hstring *varname;

			tv_val = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, (duk_hobject *) h, i);
			DUK_ASSERT(tv_val != NULL);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv_val));

			varname = DUK_TVAL_GET_STRING(tv_val);
			DUK_ASSERT(varname != NULL);
			DUK_ASSERT(DUK_HSTRING_GET_BYTELEN(varname) >= 1);

			DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
			p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U + DUK_HSTRING_GET_BYTELEN(varname), p);
			p = duk__dump_hstring_raw(p, varname);
		}
	} else {
		DUK_DD(DUK_DDPRINT("dumping function without _Formals, emit marker to indicate missing _Formals"));
		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4U, p);
		DUK_RAW_WRITEINC_U32_BE(p, DUK__NO_FORMALS);  /* marker: no formals */
	}
	return p;
}

static duk_uint8_t *duk__dump_func(duk_hthread *thr, duk_hcompfunc *func, duk_bufwriter_ctx *bw_ctx, duk_uint8_t *p) {
	duk_tval *tv, *tv_end;
	duk_instr_t *ins, *ins_end;
	duk_hobject **fn, **fn_end;
	duk_hstring *h_str;
	duk_uint32_t count_instr;
	duk_uint32_t tmp32;
	duk_uint16_t tmp16;
	duk_double_t d;

	DUK_DD(DUK_DDPRINT("dumping function %p to %p: "
	                   "consts=[%p,%p[ (%ld bytes, %ld items), "
	                   "funcs=[%p,%p[ (%ld bytes, %ld items), "
	                   "code=[%p,%p[ (%ld bytes, %ld items)",
	                   (void *) func,
	                   (void *) p,
	                   (void *) DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, func),
	                   (void *) DUK_HCOMPFUNC_GET_CONSTS_END(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_CONSTS_SIZE(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_CONSTS_COUNT(thr->heap, func),
	                   (void *) DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, func),
	                   (void *) DUK_HCOMPFUNC_GET_FUNCS_END(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_FUNCS_SIZE(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_FUNCS_COUNT(thr->heap, func),
	                   (void *) DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, func),
	                   (void *) DUK_HCOMPFUNC_GET_CODE_END(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_CODE_SIZE(thr->heap, func),
	                   (long) DUK_HCOMPFUNC_GET_CODE_COUNT(thr->heap, func)));

	DUK_ASSERT(DUK_USE_ESBC_MAX_BYTES <= 0x7fffffffUL);  /* ensures no overflow */
	count_instr = (duk_uint32_t) DUK_HCOMPFUNC_GET_CODE_COUNT(thr->heap, func);
	p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 3U * 4U + 2U * 2U + 3U * 4U + count_instr * 4U, p);

	/* Fixed header info. */
	tmp32 = count_instr;
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	tmp32 = (duk_uint32_t) DUK_HCOMPFUNC_GET_CONSTS_COUNT(thr->heap, func);
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	tmp32 = (duk_uint32_t) DUK_HCOMPFUNC_GET_FUNCS_COUNT(thr->heap, func);
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	tmp16 = func->nregs;
	DUK_RAW_WRITEINC_U16_BE(p, tmp16);
	tmp16 = func->nargs;
	DUK_RAW_WRITEINC_U16_BE(p, tmp16);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	tmp32 = func->start_line;
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
	tmp32 = func->end_line;
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);
#else
	DUK_RAW_WRITEINC_U32_BE(p, 0);
	DUK_RAW_WRITEINC_U32_BE(p, 0);
#endif
	tmp32 = DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) func);  /* masks flags, only duk_hobject flags */
	tmp32 &= ~(DUK_HOBJECT_FLAG_HAVE_FINALIZER);  /* finalizer flag is lost */
	DUK_RAW_WRITEINC_U32_BE(p, tmp32);

	/* Bytecode instructions: endian conversion needed unless
	 * platform is big endian.
	 */
	ins = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, func);
	ins_end = DUK_HCOMPFUNC_GET_CODE_END(thr->heap, func);
	DUK_ASSERT((duk_size_t) (ins_end - ins) == (duk_size_t) count_instr);
#if defined(DUK_USE_INTEGER_BE)
	duk_memcpy_unsafe((void *) p, (const void *) ins, (size_t) (ins_end - ins));
	p += (size_t) (ins_end - ins);
#else
	while (ins != ins_end) {
		tmp32 = (duk_uint32_t) (*ins);
		DUK_RAW_WRITEINC_U32_BE(p, tmp32);
		ins++;
	}
#endif

	/* Constants: variable size encoding. */
	tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, func);
	tv_end = DUK_HCOMPFUNC_GET_CONSTS_END(thr->heap, func);
	while (tv != tv_end) {
		/* constants are strings or numbers now */
		DUK_ASSERT(DUK_TVAL_IS_STRING(tv) ||
		           DUK_TVAL_IS_NUMBER(tv));

		if (DUK_TVAL_IS_STRING(tv)) {
			h_str = DUK_TVAL_GET_STRING(tv);
			DUK_ASSERT(h_str != NULL);
			DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
			p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 1U + 4U + DUK_HSTRING_GET_BYTELEN(h_str), p);
			*p++ = DUK__SER_STRING;
			p = duk__dump_hstring_raw(p, h_str);
		} else {
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
			p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 1U + 8U, p);
			*p++ = DUK__SER_NUMBER;
			d = DUK_TVAL_GET_NUMBER(tv);
			DUK_RAW_WRITEINC_DOUBLE_BE(p, d);
		}
		tv++;
	}

	/* Inner functions recursively. */
	fn = (duk_hobject **) DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, func);
	fn_end = (duk_hobject **) DUK_HCOMPFUNC_GET_FUNCS_END(thr->heap, func);
	while (fn != fn_end) {
		/* XXX: This causes recursion up to inner function depth
		 * which is normally not an issue, e.g. mark-and-sweep uses
		 * a recursion limiter to avoid C stack issues.  Avoiding
		 * this would mean some sort of a work list or just refusing
		 * to serialize deep functions.
		 */
		DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(*fn));
		p = duk__dump_func(thr, (duk_hcompfunc *) *fn, bw_ctx, p);
		fn++;
	}

	/* Lexenv and varenv are not dumped. */

	/* Object extra properties.
	 *
	 * There are some difference between function templates and functions.
	 * For example, function templates don't have .length and nargs is
	 * normally used to instantiate the functions.
	 */

	p = duk__dump_uint32_prop(thr, p, bw_ctx, (duk_hobject *) func, DUK_STRIDX_LENGTH, (duk_uint32_t) func->nargs);
#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	p = duk__dump_string_prop(thr, p, bw_ctx, (duk_hobject *) func, DUK_STRIDX_NAME);
#endif
#if defined(DUK_USE_FUNC_FILENAME_PROPERTY)
	p = duk__dump_string_prop(thr, p, bw_ctx, (duk_hobject *) func, DUK_STRIDX_FILE_NAME);
#endif
#if defined(DUK_USE_PC2LINE)
	p = duk__dump_buffer_prop(thr, p, bw_ctx, (duk_hobject *) func, DUK_STRIDX_INT_PC2LINE);
#endif
	p = duk__dump_varmap(thr, p, bw_ctx, (duk_hobject *) func);
	p = duk__dump_formals(thr, p, bw_ctx, (duk_hobject *) func);

	DUK_DD(DUK_DDPRINT("serialized function %p -> final pointer %p", (void *) func, (void *) p));

	return p;
}

/* Load a function from bytecode.  The function object returned here must
 * match what is created by duk_js_push_closure() with respect to its flags,
 * properties, etc.
 *
 * NOTE: there are intentionally no input buffer length / bound checks.
 * Adding them would be easy but wouldn't ensure memory safety as untrusted
 * or broken bytecode is unsafe during execution unless the opcodes themselves
 * are validated (which is quite complex, especially for indirect opcodes).
 */

#define DUK__ASSERT_LEFT(n) do { \
		DUK_ASSERT((duk_size_t) (p_end - p) >= (duk_size_t) (n)); \
	} while (0)

static const duk_uint8_t *duk__load_func(duk_hthread *thr, const duk_uint8_t *p, const duk_uint8_t *p_end) {
	duk_hcompfunc *h_fun;
	duk_hbuffer *h_data;
	duk_size_t data_size;
	duk_uint32_t count_instr, count_const, count_funcs;
	duk_uint32_t n;
	duk_uint32_t tmp32;
	duk_small_uint_t const_type;
	duk_uint8_t *fun_data;
	duk_uint8_t *q;
	duk_idx_t idx_base;
	duk_tval *tv1;
	duk_uarridx_t arr_idx;
	duk_uarridx_t arr_limit;
	duk_hobject *func_env;
	duk_bool_t need_pop;

	/* XXX: There's some overlap with duk_js_closure() here, but
	 * seems difficult to share code.  Ensure that the final function
	 * looks the same as created by duk_js_closure().
	 */

	DUK_ASSERT(thr != NULL);

	DUK_DD(DUK_DDPRINT("loading function, p=%p, p_end=%p", (const void *) p, (const void *) p_end));

	DUK__ASSERT_LEFT(3 * 4);
	count_instr = DUK_RAW_READINC_U32_BE(p);
	count_const = DUK_RAW_READINC_U32_BE(p);
	count_funcs = DUK_RAW_READINC_U32_BE(p);

	data_size = sizeof(duk_tval) * count_const +
	            sizeof(duk_hobject *) * count_funcs +
	            sizeof(duk_instr_t) * count_instr;

	DUK_DD(DUK_DDPRINT("instr=%ld, const=%ld, funcs=%ld, data_size=%ld",
	                   (long) count_instr, (long) count_const,
	                   (long) count_const, (long) data_size));

	/* Value stack is used to ensure reachability of constants and
	 * inner functions being loaded.  Require enough space to handle
	 * large functions correctly.
	 */
	duk_require_stack(thr, (duk_idx_t) (2 + count_const + count_funcs));
	idx_base = duk_get_top(thr);

	/* Push function object, init flags etc.  This must match
	 * duk_js_push_closure() quite carefully.
	 */
	h_fun = duk_push_hcompfunc(thr);
	DUK_ASSERT(h_fun != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) h_fun));
	DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, h_fun) == NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_FUNCS(thr->heap, h_fun) == NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_BYTECODE(thr->heap, h_fun) == NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_fun) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);

	h_fun->nregs = DUK_RAW_READINC_U16_BE(p);
	h_fun->nargs = DUK_RAW_READINC_U16_BE(p);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	h_fun->start_line = DUK_RAW_READINC_U32_BE(p);
	h_fun->end_line = DUK_RAW_READINC_U32_BE(p);
#else
	p += 8;  /* skip line info */
#endif

	/* duk_hcompfunc flags; quite version specific */
	tmp32 = DUK_RAW_READINC_U32_BE(p);
	DUK_HEAPHDR_SET_FLAGS((duk_heaphdr *) h_fun, tmp32);  /* masks flags to only change duk_hobject flags */

	/* standard prototype (no need to set here, already set) */
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_fun) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
#if 0
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, &h_fun->obj, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
#endif

	/* assert just a few critical flags */
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h_fun) == DUK_HTYPE_OBJECT);
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(&h_fun->obj));
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_IS_THREAD(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_IS_PROXY(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(&h_fun->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(&h_fun->obj));

	/* Create function 'data' buffer but don't attach it yet. */
	fun_data = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, data_size);
	DUK_ASSERT(fun_data != NULL);

	/* Load bytecode instructions. */
	DUK_ASSERT(sizeof(duk_instr_t) == 4);
	DUK__ASSERT_LEFT(count_instr * sizeof(duk_instr_t));
#if defined(DUK_USE_INTEGER_BE)
	q = fun_data + sizeof(duk_tval) * count_const + sizeof(duk_hobject *) * count_funcs;
	duk_memcpy((void *) q,
	           (const void *) p,
	           sizeof(duk_instr_t) * count_instr);
	p += sizeof(duk_instr_t) * count_instr;
#else
	q = fun_data + sizeof(duk_tval) * count_const + sizeof(duk_hobject *) * count_funcs;
	for (n = count_instr; n > 0; n--) {
		*((duk_instr_t *) (void *) q) = DUK_RAW_READINC_U32_BE(p);
		q += sizeof(duk_instr_t);
	}
#endif

	/* Load constants onto value stack but don't yet copy to buffer. */
	for (n = count_const; n > 0; n--) {
		DUK__ASSERT_LEFT(1);
		const_type = DUK_RAW_READINC_U8(p);
		switch (const_type) {
		case DUK__SER_STRING: {
			p = duk__load_string_raw(thr, p);
			break;
		}
		case DUK__SER_NUMBER: {
			/* Important to do a fastint check so that constants are
			 * properly read back as fastints.
			 */
			duk_tval tv_tmp;
			duk_double_t val;
			DUK__ASSERT_LEFT(8);
			val = DUK_RAW_READINC_DOUBLE_BE(p);
			DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(&tv_tmp, val);
			duk_push_tval(thr, &tv_tmp);
			break;
		}
		default: {
			goto format_error;
		}
		}
	}

	/* Load inner functions to value stack, but don't yet copy to buffer. */
	for (n = count_funcs; n > 0; n--) {
		p = duk__load_func(thr, p, p_end);
		if (p == NULL) {
			goto format_error;
		}
	}

	/* With constants and inner functions on value stack, we can now
	 * atomically finish the function 'data' buffer, bump refcounts,
	 * etc.
	 *
	 * Here we take advantage of the value stack being just a duk_tval
	 * array: we can just memcpy() the constants as long as we incref
	 * them afterwards.
	 */

	h_data = (duk_hbuffer *) duk_known_hbuffer(thr, idx_base + 1);
	DUK_ASSERT(!DUK_HBUFFER_HAS_DYNAMIC(h_data));
	DUK_HCOMPFUNC_SET_DATA(thr->heap, h_fun, h_data);
	DUK_HBUFFER_INCREF(thr, h_data);

	tv1 = duk_get_tval(thr, idx_base + 2);  /* may be NULL if no constants or inner funcs */
	DUK_ASSERT((count_const == 0 && count_funcs == 0) || tv1 != NULL);

	q = fun_data;
	duk_memcpy_unsafe((void *) q, (const void *) tv1, sizeof(duk_tval) * count_const);
	for (n = count_const; n > 0; n--) {
		DUK_TVAL_INCREF_FAST(thr, (duk_tval *) (void *) q);  /* no side effects */
		q += sizeof(duk_tval);
	}
	tv1 += count_const;

	DUK_HCOMPFUNC_SET_FUNCS(thr->heap, h_fun, (duk_hobject **) (void *) q);
	for (n = count_funcs; n > 0; n--) {
		duk_hobject *h_obj;

		DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv1));
		h_obj = DUK_TVAL_GET_OBJECT(tv1);
		DUK_ASSERT(h_obj != NULL);
		tv1++;
		DUK_HOBJECT_INCREF(thr, h_obj);

		*((duk_hobject **) (void *) q) = h_obj;
		q += sizeof(duk_hobject *);
	}

	DUK_HCOMPFUNC_SET_BYTECODE(thr->heap, h_fun, (duk_instr_t *) (void *) q);

	/* The function object is now reachable and refcounts are fine,
	 * so we can pop off all the temporaries.
	 */
	DUK_DDD(DUK_DDDPRINT("function is reachable, reset top; func: %!iT", duk_get_tval(thr, idx_base)));
	duk_set_top(thr, idx_base + 1);

	/* Setup function properties. */
	tmp32 = DUK_RAW_READINC_U32_BE(p);
	duk_push_u32(thr, tmp32);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_C);

#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	p = duk__load_string_raw(thr, p);  /* -> [ func funcname ] */
	func_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
	DUK_ASSERT(func_env != NULL);
	need_pop = 0;
	if (DUK_HOBJECT_HAS_NAMEBINDING((duk_hobject *) h_fun)) {
		/* Original function instance/template had NAMEBINDING.
		 * Must create a lexical environment on loading to allow
		 * recursive functions like 'function foo() { foo(); }'.
		 */
		duk_hdecenv *new_env;

		new_env = duk_hdecenv_alloc(thr,
		                            DUK_HOBJECT_FLAG_EXTENSIBLE |
		                            DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV));
		DUK_ASSERT(new_env != NULL);
		DUK_ASSERT(new_env->thread == NULL);  /* Closed. */
		DUK_ASSERT(new_env->varmap == NULL);
		DUK_ASSERT(new_env->regbase_byteoff == 0);
		DUK_HDECENV_ASSERT_VALID(new_env);
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) new_env) == NULL);
		DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) new_env, func_env);
		DUK_HOBJECT_INCREF(thr, func_env);

		func_env = (duk_hobject *) new_env;

		duk_push_hobject(thr, (duk_hobject *) new_env);

		duk_dup_m2(thr);                                  /* -> [ func funcname env funcname ] */
		duk_dup(thr, idx_base);                           /* -> [ func funcname env funcname func ] */
		duk_xdef_prop(thr, -3, DUK_PROPDESC_FLAGS_NONE);  /* -> [ func funcname env ] */

		need_pop = 1;  /* Need to pop env, but -after- updating h_fun and increfs. */
	}
	DUK_ASSERT(func_env != NULL);
	DUK_HCOMPFUNC_SET_LEXENV(thr->heap, h_fun, func_env);
	DUK_HCOMPFUNC_SET_VARENV(thr->heap, h_fun, func_env);
	DUK_HOBJECT_INCREF(thr, func_env);
	DUK_HOBJECT_INCREF(thr, func_env);
	if (need_pop) {
		duk_pop(thr);
	}
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);
#endif  /* DUK_USE_FUNC_NAME_PROPERTY */

#if defined(DUK_USE_FUNC_FILENAME_PROPERTY)
	p = duk__load_string_raw(thr, p);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_C);
#endif  /* DUK_USE_FUNC_FILENAME_PROPERTY */

	if (DUK_HOBJECT_HAS_CONSTRUCTABLE((duk_hobject *) h_fun)) {
		/* Restore empty external .prototype only for constructable
		 * functions.  The prototype object should inherit from
		 * Object.prototype.
		 */
		duk_push_object(thr);
		DUK_ASSERT(!duk_is_bare_object(thr, -1));
		duk_dup_m2(thr);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_CONSTRUCTOR, DUK_PROPDESC_FLAGS_WC);  /* func.prototype.constructor = func */
		duk_compact_m1(thr);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_PROTOTYPE, DUK_PROPDESC_FLAGS_W);
	}

#if defined(DUK_USE_PC2LINE)
	p = duk__load_buffer_raw(thr, p);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_PC2LINE, DUK_PROPDESC_FLAGS_WC);
#endif  /* DUK_USE_PC2LINE */

	duk_push_bare_object(thr);  /* _Varmap */
	for (;;) {
		/* XXX: awkward */
		p = duk__load_string_raw(thr, p);
		if (duk_get_length(thr, -1) == 0) {
			duk_pop(thr);
			break;
		}
		tmp32 = DUK_RAW_READINC_U32_BE(p);
		duk_push_u32(thr, tmp32);
		duk_put_prop(thr, -3);
	}
	duk_compact_m1(thr);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VARMAP, DUK_PROPDESC_FLAGS_NONE);

	/* _Formals may have been missing in the original function, which is
	 * handled using a marker length.
	 */
	arr_limit = DUK_RAW_READINC_U32_BE(p);
	if (arr_limit != DUK__NO_FORMALS) {
		duk_push_bare_array(thr);  /* _Formals */
		for (arr_idx = 0; arr_idx < arr_limit; arr_idx++) {
			p = duk__load_string_raw(thr, p);
			duk_put_prop_index(thr, -2, arr_idx);
		}
		duk_compact_m1(thr);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_FORMALS, DUK_PROPDESC_FLAGS_NONE);
	} else {
		DUK_DD(DUK_DDPRINT("no _Formals in dumped function"));
	}

	/* Return with final function pushed on stack top. */
	DUK_DD(DUK_DDPRINT("final loaded function: %!iT", duk_get_tval(thr, -1)));
	DUK_ASSERT_TOP(thr, idx_base + 1);
	return p;

 format_error:
	return NULL;
}

DUK_EXTERNAL void duk_dump_function(duk_hthread *thr) {
	duk_hcompfunc *func;
	duk_bufwriter_ctx bw_ctx_alloc;
	duk_bufwriter_ctx *bw_ctx = &bw_ctx_alloc;
	duk_uint8_t *p;

	DUK_ASSERT_API_ENTRY(thr);

	/* Bound functions don't have all properties so we'd either need to
	 * lookup the non-bound target function or reject bound functions.
	 * For now, bound functions are rejected with TypeError.
	 */
	func = duk_require_hcompfunc(thr, -1);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(&func->obj));

	/* Estimating the result size beforehand would be costly, so
	 * start with a reasonable size and extend as needed.
	 */
	DUK_BW_INIT_PUSHBUF(thr, bw_ctx, DUK__BYTECODE_INITIAL_ALLOC);
	p = DUK_BW_GET_PTR(thr, bw_ctx);
	*p++ = DUK__SER_MARKER;
	p = duk__dump_func(thr, func, bw_ctx, p);
	DUK_BW_SET_PTR(thr, bw_ctx, p);
	DUK_BW_COMPACT(thr, bw_ctx);

	DUK_DD(DUK_DDPRINT("serialized result: %!T", duk_get_tval(thr, -1)));

	duk_remove_m2(thr);  /* [ ... func buf ] -> [ ... buf ] */
}

DUK_EXTERNAL void duk_load_function(duk_hthread *thr) {
	const duk_uint8_t *p_buf, *p, *p_end;
	duk_size_t sz;

	DUK_ASSERT_API_ENTRY(thr);

	p_buf = (duk_uint8_t *) duk_require_buffer(thr, -1, &sz);
	DUK_ASSERT(p_buf != NULL);

	/* The caller is responsible for being sure that bytecode being loaded
	 * is valid and trusted.  Invalid bytecode can cause memory unsafe
	 * behavior directly during loading or later during bytecode execution
	 * (instruction validation would be quite complex to implement).
	 *
	 * This signature check is the only sanity check for detecting
	 * accidental invalid inputs.  The initial byte ensures no ordinary
	 * string or Symbol will be accepted by accident.
	 */
	p = p_buf;
	p_end = p_buf + sz;
	if (sz < 1 || p[0] != DUK__SER_MARKER) {
		goto format_error;
	}
	p++;

	p = duk__load_func(thr, p, p_end);
	if (p == NULL) {
		goto format_error;
	}

	duk_remove_m2(thr);  /* [ ... buf func ] -> [ ... func ] */
	return;

 format_error:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BYTECODE);
	DUK_WO_NORETURN(return;);
}

#else  /* DUK_USE_BYTECODE_DUMP_SUPPORT */

DUK_EXTERNAL void duk_dump_function(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_load_function(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}

#endif  /* DUK_USE_BYTECODE_DUMP_SUPPORT */

/* automatic undefs */
#undef DUK__ASSERT_LEFT
#undef DUK__BYTECODE_INITIAL_ALLOC
#undef DUK__NO_FORMALS
#undef DUK__SER_MARKER
#undef DUK__SER_NUMBER
#undef DUK__SER_STRING
/*
 *  Calls.
 *
 *  Protected variants should avoid ever throwing an error.  Must be careful
 *  to catch errors related to value stack manipulation and property lookup,
 *  not just the call itself.
 *
 *  The only exception is when arguments are insane, e.g. nargs/nrets are out
 *  of bounds; in such cases an error is thrown for two reasons.  First, we
 *  can't always respect the value stack input/output guarantees in such cases
 *  so the caller would end up with the value stack in an unexpected state.
 *  Second, an attempt to create an error might itself fail (although this
 *  could be avoided by pushing a preallocated object/string or a primitive
 *  value).
 */

/* #include duk_internal.h -> already included */

/*
 *  Helpers
 */

struct duk__pcall_prop_args {
	duk_idx_t obj_idx;
	duk_idx_t nargs;
	duk_small_uint_t call_flags;
};
typedef struct duk__pcall_prop_args duk__pcall_prop_args;

struct duk__pcall_method_args {
	duk_idx_t nargs;
	duk_small_uint_t call_flags;
};
typedef struct duk__pcall_method_args duk__pcall_method_args;

struct duk__pcall_args {
	duk_idx_t nargs;
	duk_small_uint_t call_flags;
};
typedef struct duk__pcall_args duk__pcall_args;

/* Compute and validate idx_func for a certain 'nargs' and 'other'
 * parameter count (1 or 2, depending on whether 'this' binding is
 * present).
 */
DUK_LOCAL duk_idx_t duk__call_get_idx_func(duk_hthread *thr, duk_idx_t nargs, duk_idx_t other) {
	duk_idx_t idx_func;

	/* XXX: byte arithmetic? */

	DUK_ASSERT(other >= 0);

	idx_func = duk_get_top(thr) - nargs - other;
	if (DUK_UNLIKELY((idx_func | nargs) < 0)) {  /* idx_func < 0 || nargs < 0; OR sign bits */
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return 0;);
	}
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));
	return idx_func;
}

/* Compute idx_func, assume index will be valid.  This is a valid assumption
 * for protected calls: nargs < 0 is checked explicitly and duk_safe_call()
 * validates the argument count.
 */
DUK_LOCAL duk_idx_t duk__call_get_idx_func_unvalidated(duk_hthread *thr, duk_idx_t nargs, duk_idx_t other) {
	duk_idx_t idx_func;

	/* XXX: byte arithmetic? */

	DUK_ASSERT(nargs >= 0);
	DUK_ASSERT(other >= 0);

	idx_func = duk_get_top(thr) - nargs - other;
	DUK_ASSERT(idx_func >= 0);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));
	return idx_func;
}

/* Prepare value stack for a method call through an object property.
 * May currently throw an error e.g. when getting the property.
 */
DUK_LOCAL void duk__call_prop_prep_stack(duk_hthread *thr, duk_idx_t normalized_obj_idx, duk_idx_t nargs) {
	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(nargs >= 0);

	DUK_DDD(DUK_DDDPRINT("duk__call_prop_prep_stack, normalized_obj_idx=%ld, nargs=%ld, stacktop=%ld",
	                     (long) normalized_obj_idx, (long) nargs, (long) duk_get_top(thr)));

	/* [... key arg1 ... argN] */

	/* duplicate key */
	duk_dup(thr, -nargs - 1);  /* Note: -nargs alone would fail for nargs == 0, this is OK */
	(void) duk_get_prop(thr, normalized_obj_idx);

	DUK_DDD(DUK_DDDPRINT("func: %!T", (duk_tval *) duk_get_tval(thr, -1)));

#if defined(DUK_USE_VERBOSE_ERRORS)
	if (DUK_UNLIKELY(!duk_is_callable(thr, -1))) {
		duk_tval *tv_base;
		duk_tval *tv_key;

		/* tv_targ is passed on stack top (at index -1). */
		tv_base = DUK_GET_TVAL_POSIDX(thr, normalized_obj_idx);
		tv_key = DUK_GET_TVAL_NEGIDX(thr, -nargs - 2);
		DUK_ASSERT(tv_base >= thr->valstack_bottom && tv_base < thr->valstack_top);
		DUK_ASSERT(tv_key >= thr->valstack_bottom && tv_key < thr->valstack_top);

		duk_call_setup_propcall_error(thr, tv_base, tv_key);
	}
#endif

	/* [... key arg1 ... argN func] */

	duk_replace(thr, -nargs - 2);

	/* [... func arg1 ... argN] */

	duk_dup(thr, normalized_obj_idx);
	duk_insert(thr, -nargs - 1);

	/* [... func this arg1 ... argN] */
}

DUK_EXTERNAL void duk_call(duk_hthread *thr, duk_idx_t nargs) {
	duk_small_uint_t call_flags;
	duk_idx_t idx_func;

	DUK_ASSERT_API_ENTRY(thr);

	idx_func = duk__call_get_idx_func(thr, nargs, 1);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));

	duk_insert_undefined(thr, idx_func + 1);

	call_flags = 0;  /* not protected, respect reclimit, not constructor */
	duk_handle_call_unprotected(thr, idx_func, call_flags);
}

DUK_EXTERNAL void duk_call_method(duk_hthread *thr, duk_idx_t nargs) {
	duk_small_uint_t call_flags;
	duk_idx_t idx_func;

	DUK_ASSERT_API_ENTRY(thr);

	idx_func = duk__call_get_idx_func(thr, nargs, 2);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));

	call_flags = 0;  /* not protected, respect reclimit, not constructor */
	duk_handle_call_unprotected(thr, idx_func, call_flags);
}

DUK_EXTERNAL void duk_call_prop(duk_hthread *thr, duk_idx_t obj_idx, duk_idx_t nargs) {
	/*
	 *  XXX: if duk_handle_call() took values through indices, this could be
	 *  made much more sensible.  However, duk_handle_call() needs to fudge
	 *  the 'this' and 'func' values to handle bound functions, which is now
	 *  done "in-place", so this is not a trivial change.
	 */

	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);  /* make absolute */
	if (DUK_UNLIKELY(nargs < 0)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return;);
	}

	duk__call_prop_prep_stack(thr, obj_idx, nargs);

	duk_call_method(thr, nargs);
}

DUK_LOCAL duk_ret_t duk__pcall_raw(duk_hthread *thr, void *udata) {
	duk__pcall_args *args;
	duk_idx_t idx_func;
	duk_int_t ret;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(udata != NULL);

	args = (duk__pcall_args *) udata;
	idx_func = duk__call_get_idx_func_unvalidated(thr, args->nargs, 1);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));

	duk_insert_undefined(thr, idx_func + 1);

	ret = duk_handle_call_unprotected(thr, idx_func, args->call_flags);
	DUK_ASSERT(ret == 0);
	DUK_UNREF(ret);

	return 1;
}

DUK_EXTERNAL duk_int_t duk_pcall(duk_hthread *thr, duk_idx_t nargs) {
	duk__pcall_args args;

	DUK_ASSERT_API_ENTRY(thr);

	args.nargs = nargs;
	if (DUK_UNLIKELY(nargs < 0)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return DUK_EXEC_ERROR;);
	}
	args.call_flags = 0;

	return duk_safe_call(thr, duk__pcall_raw, (void *) &args /*udata*/, nargs + 1 /*nargs*/, 1 /*nrets*/);
}

DUK_LOCAL duk_ret_t duk__pcall_method_raw(duk_hthread *thr, void *udata) {
	duk__pcall_method_args *args;
	duk_idx_t idx_func;
	duk_int_t ret;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(udata != NULL);

	args = (duk__pcall_method_args *) udata;

	idx_func = duk__call_get_idx_func_unvalidated(thr, args->nargs, 2);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));

	ret = duk_handle_call_unprotected(thr, idx_func, args->call_flags);
	DUK_ASSERT(ret == 0);
	DUK_UNREF(ret);

	return 1;
}

DUK_INTERNAL duk_int_t duk_pcall_method_flags(duk_hthread *thr, duk_idx_t nargs, duk_small_uint_t call_flags) {
	duk__pcall_method_args args;

	DUK_ASSERT_API_ENTRY(thr);

	args.nargs = nargs;
	if (DUK_UNLIKELY(nargs < 0)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return DUK_EXEC_ERROR;);
	}
	args.call_flags = call_flags;

	return duk_safe_call(thr, duk__pcall_method_raw, (void *) &args /*udata*/, nargs + 2 /*nargs*/, 1 /*nrets*/);
}

DUK_EXTERNAL duk_int_t duk_pcall_method(duk_hthread *thr, duk_idx_t nargs) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk_pcall_method_flags(thr, nargs, 0);
}

DUK_LOCAL duk_ret_t duk__pcall_prop_raw(duk_hthread *thr, void *udata) {
	duk__pcall_prop_args *args;
	duk_idx_t obj_idx;
	duk_int_t ret;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(udata != NULL);

	args = (duk__pcall_prop_args *) udata;

	obj_idx = duk_require_normalize_index(thr, args->obj_idx);  /* make absolute */
	duk__call_prop_prep_stack(thr, obj_idx, args->nargs);

	ret = duk_handle_call_unprotected_nargs(thr, args->nargs, args->call_flags);
	DUK_ASSERT(ret == 0);
	DUK_UNREF(ret);
	return 1;
}

DUK_EXTERNAL duk_int_t duk_pcall_prop(duk_hthread *thr, duk_idx_t obj_idx, duk_idx_t nargs) {
	duk__pcall_prop_args args;

	DUK_ASSERT_API_ENTRY(thr);

	args.obj_idx = obj_idx;
	args.nargs = nargs;
	if (DUK_UNLIKELY(nargs < 0)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return DUK_EXEC_ERROR;);
	}
	args.call_flags = 0;

	return duk_safe_call(thr, duk__pcall_prop_raw, (void *) &args /*udata*/, nargs + 1 /*nargs*/, 1 /*nrets*/);
}

DUK_EXTERNAL duk_int_t duk_safe_call(duk_hthread *thr, duk_safe_call_function func, void *udata, duk_idx_t nargs, duk_idx_t nrets) {
	duk_int_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* nargs condition; fail if: top - bottom < nargs
	 *                      <=>  top < bottom + nargs
	 * nrets condition; fail if: end - (top - nargs) < nrets
	 *                      <=>  end - top + nargs < nrets
	 *                      <=>  end + nargs < top + nrets
	 */
	/* XXX: check for any reserve? */

	if (DUK_UNLIKELY((nargs | nrets) < 0 ||  /* nargs < 0 || nrets < 0; OR sign bits */
	                 thr->valstack_top < thr->valstack_bottom + nargs ||        /* nargs too large compared to top */
	                 thr->valstack_end + nargs < thr->valstack_top + nrets)) {  /* nrets too large compared to reserve */
		DUK_D(DUK_DPRINT("not enough stack reserve for safe call or invalid arguments: "
		                 "nargs=%ld < 0 (?), nrets=%ld < 0 (?), top=%ld < bottom=%ld + nargs=%ld (?), "
		                 "end=%ld + nargs=%ld < top=%ld + nrets=%ld (?)",
		                  (long) nargs,
		                  (long) nrets,
		                  (long) (thr->valstack_top - thr->valstack),
		                  (long) (thr->valstack_bottom - thr->valstack),
		                  (long) nargs,
		                  (long) (thr->valstack_end - thr->valstack),
		                  (long) nargs,
		                  (long) (thr->valstack_top - thr->valstack),
		                  (long) nrets));
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return DUK_EXEC_ERROR;);
	}

	rc = duk_handle_safe_call(thr,           /* thread */
	                          func,          /* func */
	                          udata,         /* udata */
	                          nargs,         /* num_stack_args */
	                          nrets);        /* num_stack_res */

	return rc;
}

DUK_EXTERNAL void duk_new(duk_hthread *thr, duk_idx_t nargs) {
	duk_idx_t idx_func;

	DUK_ASSERT_API_ENTRY(thr);

	idx_func = duk__call_get_idx_func(thr, nargs, 1);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));

	duk_push_object(thr);  /* default instance; internal proto updated by call handling */
	duk_insert(thr, idx_func + 1);

	duk_handle_call_unprotected(thr, idx_func, DUK_CALL_FLAG_CONSTRUCT);
}

DUK_LOCAL duk_ret_t duk__pnew_helper(duk_hthread *thr, void *udata) {
	duk_idx_t nargs;

	DUK_ASSERT(udata != NULL);
	nargs = *((duk_idx_t *) udata);

	duk_new(thr, nargs);
	return 1;
}

DUK_EXTERNAL duk_int_t duk_pnew(duk_hthread *thr, duk_idx_t nargs) {
	duk_int_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* For now, just use duk_safe_call() to wrap duk_new().  We can't
	 * simply use a protected duk_handle_call() because pushing the
	 * default instance might throw.
	 */

	if (DUK_UNLIKELY(nargs < 0)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return DUK_EXEC_ERROR;);
	}

	rc = duk_safe_call(thr, duk__pnew_helper, (void *) &nargs /*udata*/, nargs + 1 /*nargs*/, 1 /*nrets*/);
	return rc;
}

DUK_EXTERNAL duk_bool_t duk_is_constructor_call(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT_API_ENTRY(thr);

	act = thr->callstack_curr;
	if (act != NULL) {
		return ((act->flags & DUK_ACT_FLAG_CONSTRUCT) != 0 ? 1 : 0);
	}
	return 0;
}

DUK_EXTERNAL void duk_require_constructor_call(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	if (!duk_is_constructor_call(thr)) {
		DUK_ERROR_TYPE(thr, DUK_STR_CONSTRUCT_ONLY);
		DUK_WO_NORETURN(return;);
	}
}

DUK_EXTERNAL duk_bool_t duk_is_strict_call(duk_hthread *thr) {
	duk_activation *act;

	/* For user code this could just return 1 (strict) always
	 * because all Duktape/C functions are considered strict,
	 * and strict is also the default when nothing is running.
	 * However, Duktape may call this function internally when
	 * the current activation is an ECMAScript function, so
	 * this cannot be replaced by a 'return 1' without fixing
	 * the internal call sites.
	 */

	DUK_ASSERT_API_ENTRY(thr);

	act = thr->callstack_curr;
	if (act != NULL) {
		return ((act->flags & DUK_ACT_FLAG_STRICT) != 0 ? 1 : 0);
	} else {
		/* Strict by default. */
		return 1;
	}
}

/*
 *  Duktape/C function magic
 */

DUK_EXTERNAL duk_int_t duk_get_current_magic(duk_hthread *thr) {
	duk_activation *act;
	duk_hobject *func;

	DUK_ASSERT_API_ENTRY(thr);

	act = thr->callstack_curr;
	if (act) {
		func = DUK_ACT_GET_FUNC(act);
		if (!func) {
			duk_tval *tv = &act->tv_func;
			duk_small_uint_t lf_flags;
			lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv);
			return (duk_int_t) DUK_LFUNC_FLAGS_GET_MAGIC(lf_flags);
		}
		DUK_ASSERT(func != NULL);

		if (DUK_HOBJECT_IS_NATFUNC(func)) {
			duk_hnatfunc *nf = (duk_hnatfunc *) func;
			return (duk_int_t) nf->magic;
		}
	}
	return 0;
}

DUK_EXTERNAL duk_int_t duk_get_magic(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (!DUK_HOBJECT_HAS_NATFUNC(h)) {
			goto type_error;
		}
		return (duk_int_t) ((duk_hnatfunc *) h)->magic;
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		duk_small_uint_t lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv);
		return (duk_int_t) DUK_LFUNC_FLAGS_GET_MAGIC(lf_flags);
	}

	/* fall through */
 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_UNEXPECTED_TYPE);
	DUK_WO_NORETURN(return 0;);
}

DUK_EXTERNAL void duk_set_magic(duk_hthread *thr, duk_idx_t idx, duk_int_t magic) {
	duk_hnatfunc *nf;

	DUK_ASSERT_API_ENTRY(thr);

	nf = duk_require_hnatfunc(thr, idx);
	DUK_ASSERT(nf != NULL);
	nf->magic = (duk_int16_t) magic;
}

/*
 *  Misc helpers
 */

/* Resolve a bound function on value stack top to a non-bound target
 * (leave other values as is).
 */
DUK_INTERNAL void duk_resolve_nonbound_function(duk_hthread *thr) {
	duk_tval *tv;

	DUK_HTHREAD_ASSERT_VALID(thr);

	tv = DUK_GET_TVAL_NEGIDX(thr, -1);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;

		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_HOBJECT_HAS_BOUNDFUNC(h)) {
			duk_push_tval(thr, &((duk_hboundfunc *) (void *) h)->target);
			duk_replace(thr, -2);
#if 0
			DUK_TVAL_SET_TVAL(tv, &((duk_hboundfunc *) h)->target);
			DUK_TVAL_INCREF(thr, tv);
			DUK_HOBJECT_DECREF_NORZ(thr, h);
#endif
			/* Rely on Function.prototype.bind() on never creating a bound
			 * function whose target is not proper.  This is now safe
			 * because the target is not even an internal property but a
			 * struct member.
			 */
			DUK_ASSERT(duk_is_lightfunc(thr, -1) || duk_is_callable(thr, -1));
		}
	}

	/* Lightfuncs cannot be bound but are always callable and
	 * constructable.
	 */
}
/*
 *  Encoding and decoding basic formats: hex, base64.
 *
 *  These are in-place operations which may allow an optimized implementation.
 *
 *  Base-64: https://tools.ietf.org/html/rfc4648#section-4
 */

/* #include duk_internal.h -> already included */

/*
 *  Misc helpers
 */

/* Shared handling for encode/decode argument.  Fast path handling for
 * buffer and string values because they're the most common.  In particular,
 * avoid creating a temporary string or buffer when possible.  Return value
 * is guaranteed to be non-NULL, even for zero length input.
 */
DUK_LOCAL const duk_uint8_t *duk__prep_codec_arg(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	const void *def_ptr = (const void *) out_len;  /* Any non-NULL pointer will do. */
	const void *ptr;
	duk_bool_t isbuffer;

	DUK_ASSERT(out_len != NULL);
	DUK_ASSERT(def_ptr != NULL);
	DUK_ASSERT(duk_is_valid_index(thr, idx));  /* checked by caller */

	ptr = (const void *) duk_get_buffer_data_raw(thr, idx, out_len, NULL /*def_ptr*/, 0 /*def_size*/, 0 /*throw_flag*/, &isbuffer);
	if (isbuffer) {
		DUK_ASSERT(ptr != NULL || *out_len == 0U);
		if (DUK_UNLIKELY(ptr == NULL)) {
			ptr = def_ptr;
		}
		DUK_ASSERT(ptr != NULL);
	} else {
		/* For strings a non-NULL pointer is always guaranteed because
		 * at least a NUL will be present.
		 */
		ptr = (const void *) duk_to_lstring(thr, idx, out_len);
		DUK_ASSERT(ptr != NULL);
	}
	DUK_ASSERT(ptr != NULL);
	return (const duk_uint8_t *) ptr;
}

/*
 *  Base64
 */

#if defined(DUK_USE_BASE64_SUPPORT)
/* Bytes emitted for number of padding characters in range [0,4]. */
DUK_LOCAL const duk_int8_t duk__base64_decode_nequal_step[5] = {
	3,   /* #### -> 24 bits, emit 3 bytes */
	2,   /* ###= -> 18 bits, emit 2 bytes */
	1,   /* ##== -> 12 bits, emit 1 byte */
	-1,  /* #=== -> 6 bits, error */
	0,   /* ==== -> 0 bits, emit 0 bytes */
};

#if defined(DUK_USE_BASE64_FASTPATH)
DUK_LOCAL const duk_uint8_t duk__base64_enctab_fast[64] = {
	0x41U, 0x42U, 0x43U, 0x44U, 0x45U, 0x46U, 0x47U, 0x48U, 0x49U, 0x4aU, 0x4bU, 0x4cU, 0x4dU, 0x4eU, 0x4fU, 0x50U,  /* A...P */
	0x51U, 0x52U, 0x53U, 0x54U, 0x55U, 0x56U, 0x57U, 0x58U, 0x59U, 0x5aU, 0x61U, 0x62U, 0x63U, 0x64U, 0x65U, 0x66U,  /* Q...f */
	0x67U, 0x68U, 0x69U, 0x6aU, 0x6bU, 0x6cU, 0x6dU, 0x6eU, 0x6fU, 0x70U, 0x71U, 0x72U, 0x73U, 0x74U, 0x75U, 0x76U,  /* g...v */
	0x77U, 0x78U, 0x79U, 0x7aU, 0x30U, 0x31U, 0x32U, 0x33U, 0x34U, 0x35U, 0x36U, 0x37U, 0x38U, 0x39U, 0x2bU, 0x2fU   /* w.../ */
};
#endif  /* DUK_USE_BASE64_FASTPATH */

#if defined(DUK_USE_BASE64_FASTPATH)
/* Decode table for one byte of input:
 *   -1 = allowed whitespace
 *   -2 = padding
 *   -3 = error
 *    0...63 decoded bytes
 */
DUK_LOCAL const duk_int8_t duk__base64_dectab_fast[256] = {
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -1, -1, -3, -3, -1, -3, -3,  /* 0x00...0x0f */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0x10...0x1f */
	-1, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, 62, -3, -3, -3, 63,  /* 0x20...0x2f */
	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -3, -3, -3, -2, -3, -3,  /* 0x30...0x3f */
	-3,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,  /* 0x40...0x4f */
	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -3, -3, -3, -3, -3,  /* 0x50...0x5f */
	-3, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,  /* 0x60...0x6f */
	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -3, -3, -3, -3, -3,  /* 0x70...0x7f */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0x80...0x8f */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0x90...0x9f */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0xa0...0xaf */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0xb0...0xbf */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0xc0...0xcf */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0xd0...0xdf */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,  /* 0xe0...0xef */
	-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3   /* 0xf0...0xff */
};
#endif  /* DUK_USE_BASE64_FASTPATH */

#if defined(DUK_USE_BASE64_FASTPATH)
DUK_LOCAL DUK_ALWAYS_INLINE void duk__base64_encode_fast_3(const duk_uint8_t *src, duk_uint8_t *dst) {
	duk_uint_t t;

	t = (duk_uint_t) src[0];
	t = (t << 8) + (duk_uint_t) src[1];
	t = (t << 8) + (duk_uint_t) src[2];

	dst[0] = duk__base64_enctab_fast[t >> 18];
	dst[1] = duk__base64_enctab_fast[(t >> 12) & 0x3fU];
	dst[2] = duk__base64_enctab_fast[(t >> 6) & 0x3fU];
	dst[3] = duk__base64_enctab_fast[t & 0x3fU];

#if 0
	/* Tested: not faster on x64, most likely due to aliasing between
	 * output and input index computation.
	 */
	/* aaaaaabb bbbbcccc ccdddddd */
	dst[0] = duk__base64_enctab_fast[(src[0] >> 2) & 0x3fU];
	dst[1] = duk__base64_enctab_fast[((src[0] << 4) & 0x30U) | ((src[1] >> 4) & 0x0fU)];
	dst[2] = duk__base64_enctab_fast[((src[1] << 2) & 0x3fU) | ((src[2] >> 6) & 0x03U)];
	dst[3] = duk__base64_enctab_fast[src[2] & 0x3fU];
#endif
}

DUK_LOCAL DUK_ALWAYS_INLINE void duk__base64_encode_fast_2(const duk_uint8_t *src, duk_uint8_t *dst) {
	duk_uint_t t;

	t = (duk_uint_t) src[0];
	t = (t << 8) + (duk_uint_t) src[1];
	dst[0] = duk__base64_enctab_fast[t >> 10];           /* XXXXXX-- -------- */
	dst[1] = duk__base64_enctab_fast[(t >> 4) & 0x3fU];  /* ------XX XXXX---- */
	dst[2] = duk__base64_enctab_fast[(t << 2) & 0x3fU];  /* -------- ----XXXX */
	dst[3] = DUK_ASC_EQUALS;
}

DUK_LOCAL DUK_ALWAYS_INLINE void duk__base64_encode_fast_1(const duk_uint8_t *src, duk_uint8_t *dst) {
	duk_uint_t t;

	t = (duk_uint_t) src[0];
	dst[0] = duk__base64_enctab_fast[t >> 2];            /* XXXXXX-- */
	dst[1] = duk__base64_enctab_fast[(t << 4) & 0x3fU];  /* ------XX */
	dst[2] = DUK_ASC_EQUALS;
	dst[3] = DUK_ASC_EQUALS;
}

DUK_LOCAL void duk__base64_encode_helper(const duk_uint8_t *src, duk_size_t srclen, duk_uint8_t *dst) {
	duk_size_t n;
	const duk_uint8_t *p;
	duk_uint8_t *q;

	n = srclen;
	p = src;
	q = dst;

	if (n >= 16U) {
		/* Fast path, unrolled by 4, allows interleaving.  Process
		 * 12-byte input chunks which encode to 16-char output chunks.
		 * Only enter when at least one block is emitted (avoids div+mul
		 * for short inputs too).
		 */
		const duk_uint8_t *p_end_fast;

		p_end_fast = p + ((n / 12U) * 12U);
		DUK_ASSERT(p_end_fast >= p + 12);
		do {
			duk__base64_encode_fast_3(p, q);
			duk__base64_encode_fast_3(p + 3, q + 4);
			duk__base64_encode_fast_3(p + 6, q + 8);
			duk__base64_encode_fast_3(p + 9, q + 12);
			p += 12;
			q += 16;
		} while (DUK_LIKELY(p != p_end_fast));

		DUK_ASSERT(src + srclen >= p);
		n = (duk_size_t) (src + srclen - p);
		DUK_ASSERT(n < 12U);
	}

	/* Remainder. */
	while (n >= 3U) {
		duk__base64_encode_fast_3(p, q);
		p += 3;
		q += 4;
		n -= 3U;
	}
	DUK_ASSERT(n == 0U || n == 1U || n == 2U);
	if (n == 1U) {
		duk__base64_encode_fast_1(p, q);
#if 0  /* Unnecessary. */
		p += 1;
		q += 4;
		n -= 1U;
#endif
	} else if (n == 2U) {
		duk__base64_encode_fast_2(p, q);
#if 0  /* Unnecessary. */
		p += 2;
		q += 4;
		n -= 2U;
#endif
	} else {
		DUK_ASSERT(n == 0U);  /* nothing to do */
		;
	}
}
#else  /* DUK_USE_BASE64_FASTPATH */
DUK_LOCAL void duk__base64_encode_helper(const duk_uint8_t *src, duk_size_t srclen, duk_uint8_t *dst) {
	duk_small_uint_t i, npad;
	duk_uint_t t, x, y;
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	duk_uint8_t *q;

	p = src;
	p_end = src + srclen;
	q = dst;
	npad = 0U;

	while (p < p_end) {
		/* Read 3 bytes into 't', padded by zero. */
		t = 0;
		for (i = 0; i < 3; i++) {
			t = t << 8;
			if (p < p_end) {
				t += (duk_uint_t) (*p++);
			} else {
				/* This only happens on the last loop and we're
				 * guaranteed to exit on the next loop.
				 */
				npad++;
			}
		}
		DUK_ASSERT(npad <= 2U);

		/* Emit 4 encoded characters.  If npad > 0, some of the
		 * chars will be incorrect (zero bits) but we fix up the
		 * padding after the loop.  A straightforward 64-byte
		 * lookup would be faster and cleaner, but this is shorter.
		 */
		for (i = 0; i < 4; i++) {
			x = ((t >> 18) & 0x3fU);
			t = t << 6;

			if (x <= 51U) {
				if (x <= 25) {
					y = x + DUK_ASC_UC_A;
				} else {
					y = x - 26 + DUK_ASC_LC_A;
				}
			} else {
				if (x <= 61U) {
					y = x - 52 + DUK_ASC_0;
				} else if (x == 62) {
					y = DUK_ASC_PLUS;
				} else {
					DUK_ASSERT(x == 63);
					y = DUK_ASC_SLASH;
				}
			}

			*q++ = (duk_uint8_t) y;
		}
	}

	/* Handle padding by rewriting 0-2 bogus characters at the end.
	 *
	 *  Missing bytes    npad     base64 example
	 *    0               0         ####
	 *    1               1         ###=
	 *    2               2         ##==
	 */
	DUK_ASSERT(npad <= 2U);
	while (npad > 0U) {
		*(q - npad) = DUK_ASC_EQUALS;
		npad--;
	}
}
#endif  /* DUK_USE_BASE64_FASTPATH */

#if defined(DUK_USE_BASE64_FASTPATH)
DUK_LOCAL duk_bool_t duk__base64_decode_helper(const duk_uint8_t *src, duk_size_t srclen, duk_uint8_t *dst, duk_uint8_t **out_dst_final) {
	duk_int_t x;
	duk_uint_t t;
	duk_small_uint_t n_equal;
	duk_int8_t step;
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	const duk_uint8_t *p_end_safe;
	duk_uint8_t *q;

	DUK_ASSERT(src != NULL);  /* Required by pointer arithmetic below, which fails for NULL. */

	p = src;
	p_end = src + srclen;
	p_end_safe = p_end - 8;  /* If 'src <= src_end_safe', safe to read 8 bytes. */
	q = dst;

	/* Alternate between a fast path which processes clean groups with no
	 * padding or whitespace, and a slow path which processes one arbitrary
	 * group and then re-enters the fast path.  This handles e.g. base64
	 * with newlines reasonably well because the majority of a line is in
	 * the fast path.
	 */
	for (;;) {
		/* Fast path, on each loop handle two 4-char input groups.
		 * If both are clean, emit 6 bytes and continue.  If first
		 * is clean, emit 3 bytes and drop out; otherwise emit
		 * nothing and drop out.  This approach could be extended to
		 * more groups per loop, but for inputs with e.g. periodic
		 * newlines (which are common) it might not be an improvement.
		 */
		while (DUK_LIKELY(p <= p_end_safe)) {
			duk_int_t t1, t2;

			/* The lookup byte is intentionally sign extended to
			 * (at least) 32 bits and then ORed.  This ensures
			 * that is at least 1 byte is negative, the highest
			 * bit of the accumulator will be set at the end and
			 * we don't need to check every byte.
			 *
			 * Read all input bytes first before writing output
			 * bytes to minimize aliasing.
			 */
			DUK_DDD(DUK_DDDPRINT("fast loop: p=%p, p_end_safe=%p, p_end=%p",
			                     (const void *) p, (const void *) p_end_safe, (const void *) p_end));

			t1 = (duk_int_t) duk__base64_dectab_fast[p[0]];
			t1 = (duk_int_t) ((duk_uint_t) t1 << 6) | (duk_int_t) duk__base64_dectab_fast[p[1]];
			t1 = (duk_int_t) ((duk_uint_t) t1 << 6) | (duk_int_t) duk__base64_dectab_fast[p[2]];
			t1 = (duk_int_t) ((duk_uint_t) t1 << 6) | (duk_int_t) duk__base64_dectab_fast[p[3]];

			t2 = (duk_int_t) duk__base64_dectab_fast[p[4]];
			t2 = (duk_int_t) ((duk_uint_t) t2 << 6) | (duk_int_t) duk__base64_dectab_fast[p[5]];
			t2 = (duk_int_t) ((duk_uint_t) t2 << 6) | (duk_int_t) duk__base64_dectab_fast[p[6]];
			t2 = (duk_int_t) ((duk_uint_t) t2 << 6) | (duk_int_t) duk__base64_dectab_fast[p[7]];

			q[0] = (duk_uint8_t) (((duk_uint_t) t1 >> 16) & 0xffU);
			q[1] = (duk_uint8_t) (((duk_uint_t) t1 >> 8) & 0xffU);
			q[2] = (duk_uint8_t) ((duk_uint_t) t1 & 0xffU);

			q[3] = (duk_uint8_t) (((duk_uint_t) t2 >> 16) & 0xffU);
			q[4] = (duk_uint8_t) (((duk_uint_t) t2 >> 8) & 0xffU);
			q[5] = (duk_uint8_t) ((duk_uint_t) t2 & 0xffU);

			/* Optimistic check using one branch. */
			if (DUK_LIKELY((t1 | t2) >= 0)) {
				p += 8;
				q += 6;
			} else if (t1 >= 0) {
				DUK_DDD(DUK_DDDPRINT("fast loop first group was clean, second was not, process one slow path group"));
				DUK_ASSERT(t2 < 0);
				p += 4;
				q += 3;
				break;
			} else {
				DUK_DDD(DUK_DDDPRINT("fast loop first group was not clean, second does not matter, process one slow path group"));
				DUK_ASSERT(t1 < 0);
				break;
			}
		}  /* fast path */

		/* Slow path step 1: try to scan a 4-character encoded group,
		 * end-of-input, or start-of-padding.  We exit with:
		 *   1. n_chars == 4: full group, no padding, no end-of-input.
		 *   2. n_chars < 4: partial group (may also be 0), encountered
		 *      padding or end of input.
		 *
		 * The accumulator is initialized to 1; this allows us to detect
		 * a full group by comparing >= 0x1000000 without an extra
		 * counter variable.
		 */
		t = 1UL;
		for (;;) {
			DUK_DDD(DUK_DDDPRINT("slow loop: p=%p, p_end=%p, t=%lu",
			                     (const void *) p, (const void *) p_end, (unsigned long) t));

			if (DUK_LIKELY(p < p_end)) {
				x = duk__base64_dectab_fast[*p++];
				if (DUK_LIKELY(x >= 0)) {
					DUK_ASSERT(x >= 0 && x <= 63);
					t = (t << 6) + (duk_uint_t) x;
					if (t >= 0x1000000UL) {
						break;
					}
				} else if (x == -1) {
					continue;  /* allowed ascii whitespace */
				} else if (x == -2) {
					p--;
					break;  /* start of padding */
				} else {
					DUK_ASSERT(x == -3);
					goto decode_error;
				}
			} else {
				break;  /* end of input */
			}
		}  /* slow path step 1 */

		/* Complete the padding by simulating pad characters,
		 * regardless of actual input padding chars.
		 */
		n_equal = 0;
		while (t < 0x1000000UL) {
			t = (t << 6) + 0U;
			n_equal++;
		}

		/* Slow path step 2: deal with full/partial group, padding,
		 * etc.  Note that for num chars in [0,3] we intentionally emit
		 * 3 bytes but don't step forward that much, buffer space is
		 * guaranteed in setup.
		 *
		 *  num chars:
		 *   0      ####   no output (= step 0)
		 *   1      #===   reject, 6 bits of data
		 *   2      ##==   12 bits of data, output 1 byte (= step 1)
		 *   3      ###=   18 bits of data, output 2 bytes (= step 2)
		 *   4      ####   24 bits of data, output 3 bytes (= step 3)
		 */
		q[0] = (duk_uint8_t) ((t >> 16) & 0xffU);
		q[1] = (duk_uint8_t) ((t >> 8) & 0xffU);
		q[2] = (duk_uint8_t) (t & 0xffU);

		DUK_ASSERT(n_equal <= 4);
		step = duk__base64_decode_nequal_step[n_equal];
		if (DUK_UNLIKELY(step < 0)) {
			goto decode_error;
		}
		q += step;

		/* Slow path step 3: read and ignore padding and whitespace
		 * until (a) next non-padding and non-whitespace character
		 * after which we resume the fast path, or (b) end of input.
		 * This allows us to accept missing, partial, full, and extra
		 * padding cases uniformly.  We also support concatenated
		 * base-64 documents because we resume scanning afterwards.
		 *
		 * Note that to support concatenated documents well, the '='
		 * padding found inside the input must also allow for 'extra'
		 * padding.  For example, 'Zm===' decodes to 'f' and has one
		 * extra padding char.  So, 'Zm===Zm' should decode 'ff', even
		 * though the standard break-up would be 'Zm==' + '=Zm' which
		 * doesn't make sense.
		 *
		 * We also accept prepended padding like '==Zm9', because it
		 * is equivalent to an empty document with extra padding ('==')
		 * followed by a valid document.
		 */

		for (;;) {
			if (DUK_UNLIKELY(p >= p_end)) {
				goto done;
			}
			x = duk__base64_dectab_fast[*p++];
			if (x == -1 || x == -2) {
				;  /* padding or whitespace, keep eating */
			} else {
				p--;
				break;  /* backtrack and go back to fast path, even for -1 */
			}
		}  /* slow path step 3 */
	}  /* outer fast+slow path loop */

 done:
	DUK_DDD(DUK_DDDPRINT("done; p=%p, p_end=%p",
	                     (const void *) p, (const void *) p_end));

	DUK_ASSERT(p == p_end);

	*out_dst_final = q;
	return 1;

 decode_error:
	return 0;
}
#else  /* DUK_USE_BASE64_FASTPATH */
DUK_LOCAL duk_bool_t duk__base64_decode_helper(const duk_uint8_t *src, duk_size_t srclen, duk_uint8_t *dst, duk_uint8_t **out_dst_final) {
	duk_uint_t t, x;
	duk_int_t y;
	duk_int8_t step;
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	duk_uint8_t *q;
	/* 0x09, 0x0a, or 0x0d */
	duk_uint32_t mask_white = (1U << 9) | (1U << 10) | (1U << 13);

	/* 't' tracks progress of the decoded group:
	 *
	 *  t == 1             no valid chars yet
	 *  t >= 0x40          1x6 = 6 bits shifted in
	 *  t >= 0x1000        2x6 = 12 bits shifted in
	 *  t >= 0x40000       3x6 = 18 bits shifted in
	 *  t >= 0x1000000     4x6 = 24 bits shifted in
	 *
	 * By initializing t=1 there's no need for a separate counter for
	 * the number of characters found so far.
	 */
	p = src;
	p_end = src + srclen;
	q = dst;
	t = 1UL;

	for (;;) {
		duk_small_uint_t n_equal;

		DUK_ASSERT(t >= 1U);
		if (p >= p_end) {
			/* End of input: if input exists, treat like
			 * start of padding, finish the block, then
			 * re-enter here to see we're done.
			 */
			if (t == 1U) {
				break;
			} else {
				goto simulate_padding;
			}
		}

		x = *p++;

		if (x >= 0x41U) {
			/* Valid: a-z and A-Z. */
			DUK_ASSERT(x >= 0x41U && x <= 0xffU);
			if (x >= 0x61U && x <= 0x7aU) {
				y = (duk_int_t) x - 0x61 + 26;
			} else if (x <= 0x5aU) {
				y = (duk_int_t) x - 0x41;
			} else {
				goto decode_error;
			}
		} else if (x >= 0x30U) {
			/* Valid: 0-9 and =. */
			DUK_ASSERT(x >= 0x30U && x <= 0x40U);
			if (x <= 0x39U) {
				y = (duk_int_t) x - 0x30 + 52;
			} else if (x == 0x3dU) {
				/* Skip padding and whitespace unless we're in the
				 * middle of a block.  Otherwise complete group by
				 * simulating shifting in the correct padding.
				 */
				if (t == 1U) {
					continue;
				}
				goto simulate_padding;
			} else {
				goto decode_error;
			}
		} else if (x >= 0x20U) {
			/* Valid: +, /, and 0x20 whitespace. */
			DUK_ASSERT(x >= 0x20U && x <= 0x2fU);
			if (x == 0x2bU) {
				y = 62;
			} else if (x == 0x2fU) {
				y = 63;
			} else if (x == 0x20U) {
				continue;
			} else {
				goto decode_error;
			}
		} else {
			/* Valid: whitespace. */
			duk_uint32_t m;
			DUK_ASSERT(x < 0x20U);  /* 0x00 to 0x1f */
			m = (1U << x);
			if (mask_white & m) {
				/* Allow basic ASCII whitespace. */
				continue;
			} else {
				goto decode_error;
			}
		}

		DUK_ASSERT(y >= 0 && y <= 63);
		t = (t << 6) + (duk_uint_t) y;
		if (t < 0x1000000UL) {
			continue;
		}
		/* fall through; no padding will be added */

	 simulate_padding:
		n_equal = 0;
		while (t < 0x1000000UL) {
			t = (t << 6) + 0U;
			n_equal++;
		}

		/* Output 3 bytes from 't' and advance as needed. */
		q[0] = (duk_uint8_t) ((t >> 16) & 0xffU);
		q[1] = (duk_uint8_t) ((t >> 8) & 0xffU);
		q[2] = (duk_uint8_t) (t & 0xffU);

		DUK_ASSERT(n_equal <= 4U);
		step = duk__base64_decode_nequal_step[n_equal];
		if (step < 0) {
			goto decode_error;
		}
		q += step;

		/* Re-enter loop.  The actual padding characters are skipped
		 * by the main loop.  This handles cases like missing, partial,
		 * full, and extra padding, and allows parsing of concatenated
		 * documents (with extra padding) like: Zm===Zm.  Also extra
		 * prepended padding is accepted: ===Zm9v.
		 */
		t = 1U;
	}
	DUK_ASSERT(t == 1UL);

	*out_dst_final = q;
	return 1;

 decode_error:
	return 0;
}
#endif  /* DUK_USE_BASE64_FASTPATH */

DUK_EXTERNAL const char *duk_base64_encode(duk_hthread *thr, duk_idx_t idx) {
	const duk_uint8_t *src;
	duk_size_t srclen;
	duk_size_t dstlen;
	duk_uint8_t *dst;
	const char *ret;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	src = duk__prep_codec_arg(thr, idx, &srclen);
	DUK_ASSERT(src != NULL);

	/* Compute exact output length.  Computation must not wrap; this
	 * limit works for 32-bit size_t:
	 * >>> srclen = 3221225469
	 * >>> '%x' % ((srclen + 2) / 3 * 4)
	 * 'fffffffc'
	 */
	if (srclen > 3221225469UL) {
		goto type_error;
	}
	dstlen = (srclen + 2U) / 3U * 4U;
	dst = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, dstlen);

	duk__base64_encode_helper((const duk_uint8_t *) src, srclen, dst);

	ret = duk_buffer_to_string(thr, -1);  /* Safe, result is ASCII. */
	duk_replace(thr, idx);
	return ret;

 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_BASE64_ENCODE_FAILED);
	DUK_WO_NORETURN(return NULL;);
}

DUK_EXTERNAL void duk_base64_decode(duk_hthread *thr, duk_idx_t idx) {
	const duk_uint8_t *src;
	duk_size_t srclen;
	duk_size_t dstlen;
	duk_uint8_t *dst;
	duk_uint8_t *dst_final;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	src = duk__prep_codec_arg(thr, idx, &srclen);
	DUK_ASSERT(src != NULL);

	/* Round up and add safety margin.  Avoid addition before division to
	 * avoid possibility of wrapping.  Margin includes +3 for rounding up,
	 * and +3 for one extra group: the decoder may emit and then backtrack
	 * a full group (3 bytes) from zero-sized input for technical reasons.
	 * Similarly, 'xx' may ecause 1+3 = bytes to be emitted and then
	 * backtracked.
	 */
	dstlen = (srclen / 4) * 3 + 6;  /* upper limit, assuming no whitespace etc */
	dst = (duk_uint8_t *) duk_push_dynamic_buffer(thr, dstlen);
	/* Note: for dstlen=0, dst may be NULL */

	if (!duk__base64_decode_helper((const duk_uint8_t *) src, srclen, dst, &dst_final)) {
		goto type_error;
	}

	/* XXX: convert to fixed buffer? */
	(void) duk_resize_buffer(thr, -1, (duk_size_t) (dst_final - dst));
	duk_replace(thr, idx);
	return;

 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_BASE64_DECODE_FAILED);
	DUK_WO_NORETURN(return;);
}
#else  /* DUK_USE_BASE64_SUPPORT */
DUK_EXTERNAL const char *duk_base64_encode(duk_hthread *thr, duk_idx_t idx) {
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return NULL;);
}

DUK_EXTERNAL void duk_base64_decode(duk_hthread *thr, duk_idx_t idx) {
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_BASE64_SUPPORT */

/*
 *  Hex
 */

#if defined(DUK_USE_HEX_SUPPORT)
DUK_EXTERNAL const char *duk_hex_encode(duk_hthread *thr, duk_idx_t idx) {
	const duk_uint8_t *inp;
	duk_size_t len;
	duk_size_t i;
	duk_uint8_t *buf;
	const char *ret;
#if defined(DUK_USE_HEX_FASTPATH)
	duk_size_t len_safe;
	duk_uint16_t *p16;
#endif

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	inp = duk__prep_codec_arg(thr, idx, &len);
	DUK_ASSERT(inp != NULL);

	/* Fixed buffer, no zeroing because we'll fill all the data. */
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len * 2);
	DUK_ASSERT(buf != NULL);

#if defined(DUK_USE_HEX_FASTPATH)
	DUK_ASSERT((((duk_size_t) buf) & 0x01U) == 0);   /* pointer is aligned, guaranteed for fixed buffer */
	p16 = (duk_uint16_t *) (void *) buf;
	len_safe = len & ~0x03U;
	for (i = 0; i < len_safe; i += 4) {
		p16[0] = duk_hex_enctab[inp[i]];
		p16[1] = duk_hex_enctab[inp[i + 1]];
		p16[2] = duk_hex_enctab[inp[i + 2]];
		p16[3] = duk_hex_enctab[inp[i + 3]];
		p16 += 4;
	}
	for (; i < len; i++) {
		*p16++ = duk_hex_enctab[inp[i]];
	}
#else  /* DUK_USE_HEX_FASTPATH */
	for (i = 0; i < len; i++) {
		duk_small_uint_t t;
		t = (duk_small_uint_t) inp[i];
		buf[i*2 + 0] = duk_lc_digits[t >> 4];
		buf[i*2 + 1] = duk_lc_digits[t & 0x0f];
	}
#endif  /* DUK_USE_HEX_FASTPATH */

	/* XXX: Using a string return value forces a string intern which is
	 * not always necessary.  As a rough performance measure, hex encode
	 * time for tests/perf/test-hex-encode.js dropped from ~35s to ~15s
	 * without string coercion.  Change to returning a buffer and let the
	 * caller coerce to string if necessary?
	 */

	ret = duk_buffer_to_string(thr, -1);  /* Safe, result is ASCII. */
	duk_replace(thr, idx);
	return ret;
}

DUK_EXTERNAL void duk_hex_decode(duk_hthread *thr, duk_idx_t idx) {
	const duk_uint8_t *inp;
	duk_size_t len;
	duk_size_t i;
	duk_int_t t;
	duk_uint8_t *buf;
#if defined(DUK_USE_HEX_FASTPATH)
	duk_int_t chk;
	duk_uint8_t *p;
	duk_size_t len_safe;
#endif

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	inp = duk__prep_codec_arg(thr, idx, &len);
	DUK_ASSERT(inp != NULL);

	if (len & 0x01) {
		goto type_error;
	}

	/* Fixed buffer, no zeroing because we'll fill all the data. */
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len / 2);
	DUK_ASSERT(buf != NULL);

#if defined(DUK_USE_HEX_FASTPATH)
	p = buf;
	len_safe = len & ~0x07U;
	for (i = 0; i < len_safe; i += 8) {
		t = ((duk_int_t) duk_hex_dectab_shift4[inp[i]]) |
		    ((duk_int_t) duk_hex_dectab[inp[i + 1]]);
		chk = t;
		p[0] = (duk_uint8_t) t;
		t = ((duk_int_t) duk_hex_dectab_shift4[inp[i + 2]]) |
		    ((duk_int_t) duk_hex_dectab[inp[i + 3]]);
		chk |= t;
		p[1] = (duk_uint8_t) t;
		t = ((duk_int_t) duk_hex_dectab_shift4[inp[i + 4]]) |
		    ((duk_int_t) duk_hex_dectab[inp[i + 5]]);
		chk |= t;
		p[2] = (duk_uint8_t) t;
		t = ((duk_int_t) duk_hex_dectab_shift4[inp[i + 6]]) |
		    ((duk_int_t) duk_hex_dectab[inp[i + 7]]);
		chk |= t;
		p[3] = (duk_uint8_t) t;
		p += 4;

		/* Check if any lookup above had a negative result. */
		if (DUK_UNLIKELY(chk < 0)) {
			goto type_error;
		}
	}
	for (; i < len; i += 2) {
		/* First cast to duk_int_t to sign extend, second cast to
		 * duk_uint_t to avoid signed left shift, and final cast to
		 * duk_int_t result type.
		 */
		t = (duk_int_t) ((((duk_uint_t) (duk_int_t) duk_hex_dectab[inp[i]]) << 4U) |
		                 ((duk_uint_t) (duk_int_t) duk_hex_dectab[inp[i + 1]]));
		if (DUK_UNLIKELY(t < 0)) {
			goto type_error;
		}
		*p++ = (duk_uint8_t) t;
	}
#else  /* DUK_USE_HEX_FASTPATH */
	for (i = 0; i < len; i += 2) {
		/* For invalid characters the value -1 gets extended to
		 * at least 16 bits.  If either nybble is invalid, the
		 * resulting 't' will be < 0.
		 */
		t = (duk_int_t) ((((duk_uint_t) (duk_int_t) duk_hex_dectab[inp[i]]) << 4U) |
		                 ((duk_uint_t) (duk_int_t) duk_hex_dectab[inp[i + 1]]));
		if (DUK_UNLIKELY(t < 0)) {
			goto type_error;
		}
		buf[i >> 1] = (duk_uint8_t) t;
	}
#endif  /* DUK_USE_HEX_FASTPATH */

	duk_replace(thr, idx);
	return;

 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_HEX_DECODE_FAILED);
	DUK_WO_NORETURN(return;);
}
#else  /* DUK_USE_HEX_SUPPORT */
DUK_EXTERNAL const char *duk_hex_encode(duk_hthread *thr, duk_idx_t idx) {
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return NULL;);
}
DUK_EXTERNAL void duk_hex_decode(duk_hthread *thr, duk_idx_t idx) {
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_HEX_SUPPORT */

/*
 *  JSON
 */

#if defined(DUK_USE_JSON_SUPPORT)
DUK_EXTERNAL const char *duk_json_encode(duk_hthread *thr, duk_idx_t idx) {
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t top_at_entry;
#endif
	const char *ret;

	DUK_ASSERT_API_ENTRY(thr);
#if defined(DUK_USE_ASSERTIONS)
	top_at_entry = duk_get_top(thr);
#endif

	idx = duk_require_normalize_index(thr, idx);
	duk_bi_json_stringify_helper(thr,
	                             idx /*idx_value*/,
	                             DUK_INVALID_INDEX /*idx_replacer*/,
	                             DUK_INVALID_INDEX /*idx_space*/,
	                             0 /*flags*/);
	DUK_ASSERT(duk_is_string(thr, -1));
	duk_replace(thr, idx);
	ret = duk_get_string(thr, idx);

	DUK_ASSERT(duk_get_top(thr) == top_at_entry);

	return ret;
}

DUK_EXTERNAL void duk_json_decode(duk_hthread *thr, duk_idx_t idx) {
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t top_at_entry;
#endif

	DUK_ASSERT_API_ENTRY(thr);
#if defined(DUK_USE_ASSERTIONS)
	top_at_entry = duk_get_top(thr);
#endif

	idx = duk_require_normalize_index(thr, idx);
	duk_bi_json_parse_helper(thr,
	                         idx /*idx_value*/,
	                         DUK_INVALID_INDEX /*idx_reviver*/,
	                         0 /*flags*/);
	duk_replace(thr, idx);

	DUK_ASSERT(duk_get_top(thr) == top_at_entry);
}
#else  /* DUK_USE_JSON_SUPPORT */
DUK_EXTERNAL const char *duk_json_encode(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return NULL;);
}

DUK_EXTERNAL void duk_json_decode(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_JSON_SUPPORT */
/*
 *  Compilation and evaluation
 */

/* #include duk_internal.h -> already included */

typedef struct duk__compile_raw_args duk__compile_raw_args;
struct duk__compile_raw_args {
	duk_size_t src_length;  /* should be first on 64-bit platforms */
	const duk_uint8_t *src_buffer;
	duk_uint_t flags;
};

/* Eval is just a wrapper now. */
DUK_EXTERNAL duk_int_t duk_eval_raw(duk_hthread *thr, const char *src_buffer, duk_size_t src_length, duk_uint_t flags) {
	duk_int_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: strictness is *not* inherited from the current Duktape/C.
	 * This would be confusing because the current strictness state
	 * depends on whether we're running inside a Duktape/C activation
	 * (= strict mode) or outside of any activation (= non-strict mode).
	 * See tests/api/test-eval-strictness.c for more discussion.
	 */

	/* [ ... source? filename? ] (depends on flags) */

	rc = duk_compile_raw(thr, src_buffer, src_length, flags | DUK_COMPILE_EVAL);  /* may be safe, or non-safe depending on flags */

	/* [ ... closure/error ] */

	if (rc != DUK_EXEC_SUCCESS) {
		rc = DUK_EXEC_ERROR;
		goto got_rc;
	}

	duk_push_global_object(thr);  /* explicit 'this' binding, see GH-164 */

	if (flags & DUK_COMPILE_SAFE) {
		rc = duk_pcall_method(thr, 0);
	} else {
		duk_call_method(thr, 0);
		rc = DUK_EXEC_SUCCESS;
	}

	/* [ ... result/error ] */

 got_rc:
	if (flags & DUK_COMPILE_NORESULT) {
		duk_pop(thr);
	}

	return rc;
}

/* Helper which can be called both directly and with duk_safe_call(). */
DUK_LOCAL duk_ret_t duk__do_compile(duk_hthread *thr, void *udata) {
	duk__compile_raw_args *comp_args;
	duk_uint_t flags;
	duk_hcompfunc *h_templ;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(udata != NULL);

	/* Note: strictness is not inherited from the current Duktape/C
	 * context.  Otherwise it would not be possible to compile
	 * non-strict code inside a Duktape/C activation (which is
	 * always strict now).  See tests/api/test-eval-strictness.c
	 * for discussion.
	 */

	/* [ ... source? filename? ] (depends on flags) */

	comp_args = (duk__compile_raw_args *) udata;
	flags = comp_args->flags;

	if (flags & DUK_COMPILE_NOFILENAME) {
		/* Automatic filename: 'eval' or 'input'. */
		duk_push_hstring_stridx(thr, (flags & DUK_COMPILE_EVAL) ? DUK_STRIDX_EVAL : DUK_STRIDX_INPUT);
	}

	/* [ ... source? filename ] */

	if (!comp_args->src_buffer) {
		duk_hstring *h_sourcecode;

		h_sourcecode = duk_get_hstring(thr, -2);
		if ((flags & DUK_COMPILE_NOSOURCE) ||  /* args incorrect */
		    (h_sourcecode == NULL)) {          /* e.g. duk_push_string_file_raw() pushed undefined */
			DUK_ERROR_TYPE(thr, DUK_STR_NO_SOURCECODE);
			DUK_WO_NORETURN(return 0;);
		}
		DUK_ASSERT(h_sourcecode != NULL);
		comp_args->src_buffer = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_sourcecode);
		comp_args->src_length = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h_sourcecode);
	}
	DUK_ASSERT(comp_args->src_buffer != NULL);

	if (flags & DUK_COMPILE_FUNCTION) {
		flags |= DUK_COMPILE_EVAL | DUK_COMPILE_FUNCEXPR;
	}

	/* [ ... source? filename ] */

	duk_js_compile(thr, comp_args->src_buffer, comp_args->src_length, flags);

	/* [ ... source? func_template ] */

	if (flags & DUK_COMPILE_NOSOURCE) {
		;
	} else {
		duk_remove_m2(thr);
	}

	/* [ ... func_template ] */

	h_templ = (duk_hcompfunc *) duk_known_hobject(thr, -1);
	duk_js_push_closure(thr,
	                   h_templ,
	                   thr->builtins[DUK_BIDX_GLOBAL_ENV],
	                   thr->builtins[DUK_BIDX_GLOBAL_ENV],
	                   1 /*add_auto_proto*/);
	duk_remove_m2(thr);   /* -> [ ... closure ] */

	/* [ ... closure ] */

	return 1;
}

DUK_EXTERNAL duk_int_t duk_compile_raw(duk_hthread *thr, const char *src_buffer, duk_size_t src_length, duk_uint_t flags) {
	duk__compile_raw_args comp_args_alloc;
	duk__compile_raw_args *comp_args = &comp_args_alloc;

	DUK_ASSERT_API_ENTRY(thr);

	if ((flags & DUK_COMPILE_STRLEN) && (src_buffer != NULL)) {
		/* String length is computed here to avoid multiple evaluation
		 * of a macro argument in the calling side.
		 */
		src_length = DUK_STRLEN(src_buffer);
	}

	comp_args->src_buffer = (const duk_uint8_t *) src_buffer;
	comp_args->src_length = src_length;
	comp_args->flags = flags;

	/* [ ... source? filename? ] (depends on flags) */

	if (flags & DUK_COMPILE_SAFE) {
		duk_int_t rc;
		duk_int_t nargs;
		duk_int_t nrets = 1;

		/* Arguments can be: [ source? filename? &comp_args] so that
		 * nargs is 1 to 3.  Call site encodes the correct nargs count
		 * directly into flags.
		 */
		nargs = flags & 0x07;
		DUK_ASSERT(nargs == ((flags & DUK_COMPILE_NOSOURCE) ? 0 : 1) +
		                    ((flags & DUK_COMPILE_NOFILENAME) ? 0 : 1));
		rc = duk_safe_call(thr, duk__do_compile, (void *) comp_args, nargs, nrets);

		/* [ ... closure ] */
		return rc;
	}

	(void) duk__do_compile(thr, (void *) comp_args);

	/* [ ... closure ] */
	return DUK_EXEC_SUCCESS;
}
/*
 *  Debugging related API calls
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_JSON_SUPPORT)
DUK_EXTERNAL void duk_push_context_dump(duk_hthread *thr) {
	duk_idx_t idx;
	duk_idx_t top;

	DUK_ASSERT_API_ENTRY(thr);

	/* We don't duk_require_stack() here now, but rely on the caller having
	 * enough space.
	 */

	top = duk_get_top(thr);
	duk_push_bare_array(thr);
	for (idx = 0; idx < top; idx++) {
		duk_dup(thr, idx);
		duk_put_prop_index(thr, -2, (duk_uarridx_t) idx);
	}

	/* XXX: conversion errors should not propagate outwards.
	 * Perhaps values need to be coerced individually?
	 */
	duk_bi_json_stringify_helper(thr,
	                             duk_get_top_index(thr),  /*idx_value*/
	                             DUK_INVALID_INDEX,  /*idx_replacer*/
	                             DUK_INVALID_INDEX,  /*idx_space*/
	                             DUK_JSON_FLAG_EXT_CUSTOM |
	                             DUK_JSON_FLAG_ASCII_ONLY |
	                             DUK_JSON_FLAG_AVOID_KEY_QUOTES /*flags*/);

	duk_push_sprintf(thr, "ctx: top=%ld, stack=%s", (long) top, (const char *) duk_safe_to_string(thr, -1));
	duk_replace(thr, -3);  /* [ ... arr jsonx(arr) res ] -> [ ... res jsonx(arr) ] */
	duk_pop(thr);
	DUK_ASSERT(duk_is_string(thr, -1));
}
#else  /* DUK_USE_JSON_SUPPORT */
DUK_EXTERNAL void duk_push_context_dump(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_JSON_SUPPORT */

#if defined(DUK_USE_DEBUGGER_SUPPORT)

DUK_EXTERNAL void duk_debugger_attach(duk_hthread *thr,
                                      duk_debug_read_function read_cb,
                                      duk_debug_write_function write_cb,
                                      duk_debug_peek_function peek_cb,
                                      duk_debug_read_flush_function read_flush_cb,
                                      duk_debug_write_flush_function write_flush_cb,
                                      duk_debug_request_function request_cb,
                                      duk_debug_detached_function detached_cb,
                                      void *udata) {
	duk_heap *heap;
	const char *str;
	duk_size_t len;

	/* XXX: should there be an error or an automatic detach if
	 * already attached?
	 */

	DUK_D(DUK_DPRINT("application called duk_debugger_attach()"));

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(read_cb != NULL);
	DUK_ASSERT(write_cb != NULL);
	/* Other callbacks are optional. */

	heap = thr->heap;
	heap->dbg_read_cb = read_cb;
	heap->dbg_write_cb = write_cb;
	heap->dbg_peek_cb = peek_cb;
	heap->dbg_read_flush_cb = read_flush_cb;
	heap->dbg_write_flush_cb = write_flush_cb;
	heap->dbg_request_cb = request_cb;
	heap->dbg_detached_cb = detached_cb;
	heap->dbg_udata = udata;
	heap->dbg_have_next_byte = 0;

	/* Start in paused state. */
	heap->dbg_processing = 0;
	heap->dbg_state_dirty = 0;
	heap->dbg_force_restart = 0;
	heap->dbg_pause_flags = 0;
	heap->dbg_pause_act = NULL;
	heap->dbg_pause_startline = 0;
	heap->dbg_exec_counter = 0;
	heap->dbg_last_counter = 0;
	heap->dbg_last_time = 0.0;
	duk_debug_set_paused(heap);  /* XXX: overlap with fields above */

	/* Send version identification and flush right afterwards.  Note that
	 * we must write raw, unframed bytes here.
	 */
	duk_push_sprintf(thr, "%ld %ld %s %s\n",
	                 (long) DUK_DEBUG_PROTOCOL_VERSION,
	                 (long) DUK_VERSION,
	                 (const char *) DUK_GIT_DESCRIBE,
	                 (const char *) DUK_USE_TARGET_INFO);
	str = duk_get_lstring(thr, -1, &len);
	DUK_ASSERT(str != NULL);
	duk_debug_write_bytes(thr, (const duk_uint8_t *) str, len);
	duk_debug_write_flush(thr);
	duk_pop(thr);
}

DUK_EXTERNAL void duk_debugger_detach(duk_hthread *thr) {
	DUK_D(DUK_DPRINT("application called duk_debugger_detach()"));

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);

	/* Can be called multiple times with no harm. */
	duk_debug_do_detach(thr->heap);
}

DUK_EXTERNAL void duk_debugger_cooperate(duk_hthread *thr) {
	duk_bool_t processed_messages;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);

	if (!duk_debug_is_attached(thr->heap)) {
		return;
	}
	if (thr->callstack_curr != NULL || thr->heap->dbg_processing) {
		/* Calling duk_debugger_cooperate() while Duktape is being
		 * called into is not supported.  This is not a 100% check
		 * but prevents any damage in most cases.
		 */
		return;
	}

	processed_messages = duk_debug_process_messages(thr, 1 /*no_block*/);
	DUK_UNREF(processed_messages);
}

DUK_EXTERNAL duk_bool_t duk_debugger_notify(duk_hthread *thr, duk_idx_t nvalues) {
	duk_idx_t top;
	duk_idx_t idx;
	duk_bool_t ret = 0;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);

	DUK_D(DUK_DPRINT("application called duk_debugger_notify() with nvalues=%ld", (long) nvalues));

	top = duk_get_top(thr);
	if (top < nvalues) {
		DUK_ERROR_RANGE(thr, "not enough stack values for notify");
		DUK_WO_NORETURN(return 0;);
	}
	if (duk_debug_is_attached(thr->heap)) {
		duk_debug_write_notify(thr, DUK_DBG_CMD_APPNOTIFY);
		for (idx = top - nvalues; idx < top; idx++) {
			duk_tval *tv = DUK_GET_TVAL_POSIDX(thr, idx);
			duk_debug_write_tval(thr, tv);
		}
		duk_debug_write_eom(thr);

		/* Return non-zero (true) if we have a good reason to believe
		 * the notify was delivered; if we're still attached at least
		 * a transport error was not indicated by the transport write
		 * callback.  This is not a 100% guarantee of course.
		 */
		if (duk_debug_is_attached(thr->heap)) {
			ret = 1;
		}
	}
	duk_pop_n(thr, nvalues);
	return ret;
}

DUK_EXTERNAL void duk_debugger_pause(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);

	DUK_D(DUK_DPRINT("application called duk_debugger_pause()"));

	/* Treat like a debugger statement: ignore when not attached. */
	if (duk_debug_is_attached(thr->heap)) {
		if (duk_debug_is_paused(thr->heap)) {
			DUK_D(DUK_DPRINT("duk_debugger_pause() called when already paused; ignoring"));
		} else {
			duk_debug_set_paused(thr->heap);

			/* Pause on the next opcode executed.  This is always safe to do even
			 * inside the debugger message loop: the interrupt counter will be reset
			 * to its proper value when the message loop exits.
			 */
			thr->interrupt_init = 1;
			thr->interrupt_counter = 0;
		}
	}
}

#else  /* DUK_USE_DEBUGGER_SUPPORT */

DUK_EXTERNAL void duk_debugger_attach(duk_hthread *thr,
                                      duk_debug_read_function read_cb,
                                      duk_debug_write_function write_cb,
                                      duk_debug_peek_function peek_cb,
                                      duk_debug_read_flush_function read_flush_cb,
                                      duk_debug_write_flush_function write_flush_cb,
                                      duk_debug_request_function request_cb,
                                      duk_debug_detached_function detached_cb,
                                      void *udata) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(read_cb);
	DUK_UNREF(write_cb);
	DUK_UNREF(peek_cb);
	DUK_UNREF(read_flush_cb);
	DUK_UNREF(write_flush_cb);
	DUK_UNREF(request_cb);
	DUK_UNREF(detached_cb);
	DUK_UNREF(udata);
	DUK_ERROR_TYPE(thr, "no debugger support");
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_debugger_detach(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ERROR_TYPE(thr, "no debugger support");
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_debugger_cooperate(duk_hthread *thr) {
	/* nop */
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(thr);
}

DUK_EXTERNAL duk_bool_t duk_debugger_notify(duk_hthread *thr, duk_idx_t nvalues) {
	duk_idx_t top;

	DUK_ASSERT_API_ENTRY(thr);

	top = duk_get_top(thr);
	if (top < nvalues) {
		DUK_ERROR_RANGE_INVALID_COUNT(thr);
		DUK_WO_NORETURN(return 0;);
	}

	/* No debugger support, just pop values. */
	duk_pop_n(thr, nvalues);
	return 0;
}

DUK_EXTERNAL void duk_debugger_pause(duk_hthread *thr) {
	/* Treat like debugger statement: nop */
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(thr);
}

#endif  /* DUK_USE_DEBUGGER_SUPPORT */
/*
 *  Heap creation and destruction
 */

/* #include duk_internal.h -> already included */

typedef struct duk_internal_thread_state duk_internal_thread_state;

struct duk_internal_thread_state {
	duk_ljstate lj;
	duk_bool_t creating_error;
	duk_hthread *curr_thread;
	duk_int_t call_recursion_depth;
};

DUK_EXTERNAL duk_hthread *duk_create_heap(duk_alloc_function alloc_func,
                                          duk_realloc_function realloc_func,
                                          duk_free_function free_func,
                                          void *heap_udata,
                                          duk_fatal_function fatal_handler) {
	duk_heap *heap = NULL;
	duk_hthread *thr;

	/* Assume that either all memory funcs are NULL or non-NULL, mixed
	 * cases will now be unsafe.
	 */

	/* XXX: just assert non-NULL values here and make caller arguments
	 * do the defaulting to the default implementations (smaller code)?
	 */

	if (!alloc_func) {
		DUK_ASSERT(realloc_func == NULL);
		DUK_ASSERT(free_func == NULL);
#if defined(DUK_USE_PROVIDE_DEFAULT_ALLOC_FUNCTIONS)
		alloc_func = duk_default_alloc_function;
		realloc_func = duk_default_realloc_function;
		free_func = duk_default_free_function;
#else
		DUK_D(DUK_DPRINT("no allocation functions given and no default providers"));
		return NULL;
#endif
	} else {
		DUK_ASSERT(realloc_func != NULL);
		DUK_ASSERT(free_func != NULL);
	}

	if (!fatal_handler) {
		fatal_handler = duk_default_fatal_handler;
	}

	DUK_ASSERT(alloc_func != NULL);
	DUK_ASSERT(realloc_func != NULL);
	DUK_ASSERT(free_func != NULL);
	DUK_ASSERT(fatal_handler != NULL);

	heap = duk_heap_alloc(alloc_func, realloc_func, free_func, heap_udata, fatal_handler);
	if (!heap) {
		return NULL;
	}
	thr = heap->heap_thread;
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	return thr;
}

DUK_EXTERNAL void duk_destroy_heap(duk_hthread *thr) {
	duk_heap *heap;

	if (!thr) {
		return;
	}
	DUK_ASSERT_API_ENTRY(thr);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	duk_heap_free(heap);
}

DUK_EXTERNAL void duk_suspend(duk_hthread *thr, duk_thread_state *state) {
	duk_internal_thread_state *snapshot = (duk_internal_thread_state *) (void *) state;
	duk_heap *heap;
	duk_ljstate *lj;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(state != NULL);  /* unvalidated */

	/* Currently not supported when called from within a finalizer.
	 * If that is done, the finalizer will remain running indefinitely,
	 * preventing other finalizers from executing.  The assert is a bit
	 * wider, checking that it would be OK to run pending finalizers.
	 */
	DUK_ASSERT(thr->heap->pf_prevent_count == 0);

	/* Currently not supported to duk_suspend() from an errCreate()
	 * call.
	 */
	DUK_ASSERT(thr->heap->creating_error == 0);

	heap = thr->heap;
	lj = &heap->lj;

	duk_push_tval(thr, &lj->value1);
	duk_push_tval(thr, &lj->value2);

	/* XXX: creating_error == 0 is asserted above, so no need to store. */
	duk_memcpy((void *) &snapshot->lj, (const void *) lj, sizeof(duk_ljstate));
	snapshot->creating_error = heap->creating_error;
	snapshot->curr_thread = heap->curr_thread;
	snapshot->call_recursion_depth = heap->call_recursion_depth;

	lj->jmpbuf_ptr = NULL;
	lj->type = DUK_LJ_TYPE_UNKNOWN;
	DUK_TVAL_SET_UNDEFINED(&lj->value1);
	DUK_TVAL_SET_UNDEFINED(&lj->value2);
	heap->creating_error = 0;
	heap->curr_thread = NULL;
	heap->call_recursion_depth = 0;
}

DUK_EXTERNAL void duk_resume(duk_hthread *thr, const duk_thread_state *state) {
	const duk_internal_thread_state *snapshot = (const duk_internal_thread_state *) (const void *) state;
	duk_heap *heap;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(state != NULL);  /* unvalidated */

	/* Shouldn't be necessary if duk_suspend() is called before
	 * duk_resume(), but assert in case API sequence is incorrect.
	 */
	DUK_ASSERT(thr->heap->pf_prevent_count == 0);
	DUK_ASSERT(thr->heap->creating_error == 0);

	heap = thr->heap;

	duk_memcpy((void *) &heap->lj, (const void *) &snapshot->lj, sizeof(duk_ljstate));
	heap->creating_error = snapshot->creating_error;
	heap->curr_thread = snapshot->curr_thread;
	heap->call_recursion_depth = snapshot->call_recursion_depth;

	duk_pop_2(thr);
}

/* XXX: better place for this */
DUK_EXTERNAL void duk_set_global_object(duk_hthread *thr) {
	duk_hobject *h_glob;
	duk_hobject *h_prev_glob;
	duk_hobjenv *h_env;
	duk_hobject *h_prev_env;

	DUK_ASSERT_API_ENTRY(thr);

	DUK_D(DUK_DPRINT("replace global object with: %!T", duk_get_tval(thr, -1)));

	h_glob = duk_require_hobject(thr, -1);
	DUK_ASSERT(h_glob != NULL);

	/*
	 *  Replace global object.
	 */

	h_prev_glob = thr->builtins[DUK_BIDX_GLOBAL];
	DUK_UNREF(h_prev_glob);
	thr->builtins[DUK_BIDX_GLOBAL] = h_glob;
	DUK_HOBJECT_INCREF(thr, h_glob);
	DUK_HOBJECT_DECREF_ALLOWNULL(thr, h_prev_glob);  /* side effects, in theory (referenced by global env) */

	/*
	 *  Replace lexical environment for global scope
	 *
	 *  Create a new object environment for the global lexical scope.
	 *  We can't just reset the _Target property of the current one,
	 *  because the lexical scope is shared by other threads with the
	 *  same (initial) built-ins.
	 */

	h_env = duk_hobjenv_alloc(thr,
	                          DUK_HOBJECT_FLAG_EXTENSIBLE |
	                          DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJENV));
	DUK_ASSERT(h_env != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_env) == NULL);

	DUK_ASSERT(h_env->target == NULL);
	DUK_ASSERT(h_glob != NULL);
	h_env->target = h_glob;
	DUK_HOBJECT_INCREF(thr, h_glob);
	DUK_ASSERT(h_env->has_this == 0);

	/* [ ... new_glob ] */

	h_prev_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
	thr->builtins[DUK_BIDX_GLOBAL_ENV] = (duk_hobject *) h_env;
	DUK_HOBJECT_INCREF(thr, (duk_hobject *) h_env);
	DUK_HOBJECT_DECREF_ALLOWNULL(thr, h_prev_env);  /* side effects */
	DUK_UNREF(h_env);  /* without refcounts */
	DUK_UNREF(h_prev_env);

	/* [ ... new_glob ] */

	duk_pop(thr);

	/* [ ... ] */
}
/*
 *  Inspection
 */

/* #include duk_internal.h -> already included */

/* For footprint efficient multiple value setting: arrays are much better than
 * varargs, format string with parsing is often better than string pointer arrays.
 */
DUK_LOCAL void duk__inspect_multiple_uint(duk_hthread *thr, const char *fmt, duk_int_t *vals) {
	duk_int_t val;
	const char *p;
	const char *p_curr;
	duk_size_t len;

	for (p = fmt;;) {
		len = DUK_STRLEN(p);
		p_curr = p;
		p += len + 1;
		if (len == 0) {
			/* Double NUL (= empty key) terminates. */
			break;
		}
		val = *vals++;
		if (val >= 0) {
			/* Negative values are markers to skip key. */
			duk_push_string(thr, p_curr);
			duk_push_int(thr, val);
			duk_put_prop(thr, -3);
		}
	}
}

/* Raw helper to extract internal information / statistics about a value.
 * The return value is an object with properties that are version specific.
 * The properties must not expose anything that would lead to security
 * issues (e.g. exposing compiled function 'data' buffer might be an issue).
 * Currently only counts and sizes and such are given so there shouldn't
 * be security implications.
 */

#define DUK__IDX_TYPE     0
#define DUK__IDX_ITAG     1
#define DUK__IDX_REFC     2
#define DUK__IDX_HBYTES   3
#define DUK__IDX_CLASS    4
#define DUK__IDX_PBYTES   5
#define DUK__IDX_ESIZE    6
#define DUK__IDX_ENEXT    7
#define DUK__IDX_ASIZE    8
#define DUK__IDX_HSIZE    9
#define DUK__IDX_BCBYTES  10
#define DUK__IDX_DBYTES   11
#define DUK__IDX_TSTATE   12
#define DUK__IDX_VARIANT  13

DUK_EXTERNAL void duk_inspect_value(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_heaphdr *h;
	/* The temporary values should be in an array rather than individual
	 * variables which (in practice) ensures that the compiler won't map
	 * them to registers and emit a lot of unnecessary shuffling code.
	 */
	duk_int_t vals[14];

	DUK_ASSERT_API_ENTRY(thr);

	/* Assume two's complement and set everything to -1. */
	duk_memset((void *) &vals, (int) 0xff, sizeof(vals));
	DUK_ASSERT(vals[DUK__IDX_TYPE] == -1);  /* spot check one */

	tv = duk_get_tval_or_unused(thr, idx);
	h = (DUK_TVAL_IS_HEAP_ALLOCATED(tv) ? DUK_TVAL_GET_HEAPHDR(tv) : NULL);

	vals[DUK__IDX_TYPE] = duk_get_type_tval(tv);
	vals[DUK__IDX_ITAG] = (duk_int_t) DUK_TVAL_GET_TAG(tv);

	duk_push_bare_object(thr);  /* Invalidates 'tv'. */
	tv = NULL;

	if (h == NULL) {
		goto finish;
	}
	duk_push_pointer(thr, (void *) h);
	duk_put_prop_literal(thr, -2, "hptr");

#if 0
	/* Covers a lot of information, e.g. buffer and string variants. */
	duk_push_uint(thr, (duk_uint_t) DUK_HEAPHDR_GET_FLAGS(h));
	duk_put_prop_literal(thr, -2, "hflags");
#endif

#if defined(DUK_USE_REFERENCE_COUNTING)
	vals[DUK__IDX_REFC] = (duk_int_t) DUK_HEAPHDR_GET_REFCOUNT(h);
#endif
	vals[DUK__IDX_VARIANT] = 0;

	/* Heaphdr size and additional allocation size, followed by
	 * type specific stuff (with varying value count).
	 */
	switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING: {
		duk_hstring *h_str = (duk_hstring *) h;
		vals[DUK__IDX_HBYTES] = (duk_int_t) (sizeof(duk_hstring) + DUK_HSTRING_GET_BYTELEN(h_str) + 1);
#if defined(DUK_USE_HSTRING_EXTDATA)
		if (DUK_HSTRING_HAS_EXTDATA(h_str)) {
			vals[DUK__IDX_VARIANT] = 1;
		}
#endif
		break;
	}
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h_obj = (duk_hobject *) h;

		/* XXX: variants here are maybe pointless; class is enough? */
		if (DUK_HOBJECT_IS_ARRAY(h_obj)) {
			vals[DUK__IDX_HBYTES] = sizeof(duk_harray);
		} else if (DUK_HOBJECT_IS_COMPFUNC(h_obj)) {
			vals[DUK__IDX_HBYTES] = sizeof(duk_hcompfunc);
		} else if (DUK_HOBJECT_IS_NATFUNC(h_obj)) {
			vals[DUK__IDX_HBYTES] = sizeof(duk_hnatfunc);
		} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
			vals[DUK__IDX_HBYTES] = sizeof(duk_hthread);
			vals[DUK__IDX_TSTATE] = ((duk_hthread *) h_obj)->state;
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		} else if (DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
			vals[DUK__IDX_HBYTES] = sizeof(duk_hbufobj);
			/* XXX: some size information */
#endif
		} else {
			vals[DUK__IDX_HBYTES] = (duk_small_uint_t) sizeof(duk_hobject);
		}

		vals[DUK__IDX_CLASS] = (duk_int_t) DUK_HOBJECT_GET_CLASS_NUMBER(h_obj);
		vals[DUK__IDX_PBYTES] = (duk_int_t) DUK_HOBJECT_P_ALLOC_SIZE(h_obj);
		vals[DUK__IDX_ESIZE] = (duk_int_t) DUK_HOBJECT_GET_ESIZE(h_obj);
		vals[DUK__IDX_ENEXT] = (duk_int_t) DUK_HOBJECT_GET_ENEXT(h_obj);
		vals[DUK__IDX_ASIZE] = (duk_int_t) DUK_HOBJECT_GET_ASIZE(h_obj);
		vals[DUK__IDX_HSIZE] = (duk_int_t) DUK_HOBJECT_GET_HSIZE(h_obj);

		/* Note: e_next indicates the number of gc-reachable entries
		 * in the entry part, and also indicates the index where the
		 * next new property would be inserted.  It does *not* indicate
		 * the number of non-NULL keys present in the object.  That
		 * value could be counted separately but requires a pass through
		 * the key list.
		 */

		if (DUK_HOBJECT_IS_COMPFUNC(h_obj)) {
			duk_hbuffer *h_data = (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(thr->heap, (duk_hcompfunc *) h_obj);
			vals[DUK__IDX_BCBYTES] = (duk_int_t) (h_data ? DUK_HBUFFER_GET_SIZE(h_data) : 0);
		}
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h_buf = (duk_hbuffer *) h;

		if (DUK_HBUFFER_HAS_DYNAMIC(h_buf)) {
			if (DUK_HBUFFER_HAS_EXTERNAL(h_buf)) {
				vals[DUK__IDX_VARIANT] = 2;  /* buffer variant 2: external */
				vals[DUK__IDX_HBYTES] = (duk_uint_t) (sizeof(duk_hbuffer_external));
			} else {
				/* When alloc_size == 0 the second allocation may not
				 * actually exist.
				 */
				vals[DUK__IDX_VARIANT] = 1;  /* buffer variant 1: dynamic */
				vals[DUK__IDX_HBYTES] = (duk_uint_t) (sizeof(duk_hbuffer_dynamic));
			}
			vals[DUK__IDX_DBYTES] = (duk_int_t) (DUK_HBUFFER_GET_SIZE(h_buf));
		} else {
			DUK_ASSERT(vals[DUK__IDX_VARIANT] == 0);  /* buffer variant 0: fixed */
			vals[DUK__IDX_HBYTES] = (duk_int_t) (sizeof(duk_hbuffer_fixed) + DUK_HBUFFER_GET_SIZE(h_buf));
		}
		break;
	}
	}

 finish:
	duk__inspect_multiple_uint(thr,
	    "type" "\x00" "itag" "\x00" "refc" "\x00" "hbytes" "\x00" "class" "\x00"
	    "pbytes" "\x00" "esize" "\x00" "enext" "\x00" "asize" "\x00" "hsize" "\x00"
	    "bcbytes" "\x00" "dbytes" "\x00" "tstate" "\x00" "variant" "\x00" "\x00",
	    (duk_int_t *) &vals);
}

DUK_EXTERNAL void duk_inspect_callstack_entry(duk_hthread *thr, duk_int_t level) {
	duk_activation *act;
	duk_uint_fast32_t pc;
	duk_uint_fast32_t line;

	DUK_ASSERT_API_ENTRY(thr);

	/* -1   = top callstack entry
	 * -2   = caller of level -1
	 * etc
	 */
	act = duk_hthread_get_activation_for_level(thr, level);
	if (act == NULL) {
		duk_push_undefined(thr);
		return;
	}
	duk_push_bare_object(thr);

	/* Relevant PC is just before current one because PC is
	 * post-incremented.  This should match what error augment
	 * code does.
	 */
	pc = duk_hthread_get_act_prev_pc(thr, act);

	duk_push_tval(thr, &act->tv_func);

	duk_push_uint(thr, (duk_uint_t) pc);
	duk_put_prop_stridx_short(thr, -3, DUK_STRIDX_PC);

#if defined(DUK_USE_PC2LINE)
	line = duk_hobject_pc2line_query(thr, -1, pc);
#else
	line = 0;
#endif
	duk_push_uint(thr, (duk_uint_t) line);
	duk_put_prop_stridx_short(thr, -3, DUK_STRIDX_LINE_NUMBER);

	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_LC_FUNCTION);
	/* Providing access to e.g. act->lex_env would be dangerous: these
	 * internal structures must never be accessible to the application.
	 * Duktape relies on them having consistent data, and this consistency
	 * is only asserted for, not checked for.
	 */
}

/* automatic undefs */
#undef DUK__IDX_ASIZE
#undef DUK__IDX_BCBYTES
#undef DUK__IDX_CLASS
#undef DUK__IDX_DBYTES
#undef DUK__IDX_ENEXT
#undef DUK__IDX_ESIZE
#undef DUK__IDX_HBYTES
#undef DUK__IDX_HSIZE
#undef DUK__IDX_ITAG
#undef DUK__IDX_PBYTES
#undef DUK__IDX_REFC
#undef DUK__IDX_TSTATE
#undef DUK__IDX_TYPE
#undef DUK__IDX_VARIANT
/*
 *  Memory calls.
 */

/* #include duk_internal.h -> already included */

DUK_EXTERNAL void *duk_alloc_raw(duk_hthread *thr, duk_size_t size) {
	DUK_ASSERT_API_ENTRY(thr);

	return DUK_ALLOC_RAW(thr->heap, size);
}

DUK_EXTERNAL void duk_free_raw(duk_hthread *thr, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_FREE_RAW(thr->heap, ptr);
}

DUK_EXTERNAL void *duk_realloc_raw(duk_hthread *thr, void *ptr, duk_size_t size) {
	DUK_ASSERT_API_ENTRY(thr);

	return DUK_REALLOC_RAW(thr->heap, ptr, size);
}

DUK_EXTERNAL void *duk_alloc(duk_hthread *thr, duk_size_t size) {
	DUK_ASSERT_API_ENTRY(thr);

	return DUK_ALLOC(thr->heap, size);
}

DUK_EXTERNAL void duk_free(duk_hthread *thr, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_FREE_CHECKED(thr, ptr);
}

DUK_EXTERNAL void *duk_realloc(duk_hthread *thr, void *ptr, duk_size_t size) {
	DUK_ASSERT_API_ENTRY(thr);

	/*
	 *  Note: since this is an exposed API call, there should be
	 *  no way a mark-and-sweep could have a side effect on the
	 *  memory allocation behind 'ptr'; the pointer should never
	 *  be something that Duktape wants to change.
	 *
	 *  Thus, no need to use DUK_REALLOC_INDIRECT (and we don't
	 *  have the storage location here anyway).
	 */

	return DUK_REALLOC(thr->heap, ptr, size);
}

DUK_EXTERNAL void duk_get_memory_functions(duk_hthread *thr, duk_memory_functions *out_funcs) {
	duk_heap *heap;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(out_funcs != NULL);
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

	heap = thr->heap;
	out_funcs->alloc_func = heap->alloc_func;
	out_funcs->realloc_func = heap->realloc_func;
	out_funcs->free_func = heap->free_func;
	out_funcs->udata = heap->heap_udata;
}

DUK_EXTERNAL void duk_gc(duk_hthread *thr, duk_uint_t flags) {
	duk_heap *heap;
	duk_small_uint_t ms_flags;

	DUK_ASSERT_API_ENTRY(thr);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	DUK_D(DUK_DPRINT("mark-and-sweep requested by application"));
	DUK_ASSERT(DUK_GC_COMPACT == DUK_MS_FLAG_EMERGENCY);  /* Compact flag is 1:1 with emergency flag which forces compaction. */
	ms_flags = (duk_small_uint_t) flags;
	duk_heap_mark_and_sweep(heap, ms_flags);
}
/*
 *  Object handling: property access and other support functions.
 */

/* #include duk_internal.h -> already included */

/*
 *  Property handling
 *
 *  The API exposes only the most common property handling functions.
 *  The caller can invoke ECMAScript built-ins for full control (e.g.
 *  defineProperty, getOwnPropertyDescriptor).
 */

DUK_EXTERNAL duk_bool_t duk_get_prop(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_bool_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: copying tv_obj and tv_key to locals to shield against a valstack
	 * resize is not necessary for a property get right now.
	 */

	tv_obj = duk_require_tval(thr, obj_idx);
	tv_key = duk_require_tval(thr, -1);

	rc = duk_hobject_getprop(thr, tv_obj, tv_key);
	DUK_ASSERT(rc == 0 || rc == 1);
	/* a value is left on stack regardless of rc */

	duk_remove_m2(thr);  /* remove key */
	DUK_ASSERT(duk_is_undefined(thr, -1) || rc == 1);
	return rc;  /* 1 if property found, 0 otherwise */
}

DUK_EXTERNAL duk_bool_t duk_get_prop_string(duk_hthread *thr, duk_idx_t obj_idx, const char *key) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_string(thr, key);
	return duk_get_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_get_prop_lstring(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_lstring(thr, key, key_len);
	return duk_get_prop(thr, obj_idx);
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_get_prop_literal_raw(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_literal_raw(thr, key, key_len);
	return duk_get_prop(thr, obj_idx);
}
#endif

DUK_EXTERNAL duk_bool_t duk_get_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_uarridx(thr, arr_idx);
	return duk_get_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_get_prop_heapptr(duk_hthread *thr, duk_idx_t obj_idx, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_heapptr(thr, ptr);  /* NULL -> 'undefined' */
	return duk_get_prop(thr, obj_idx);
}

DUK_INTERNAL duk_bool_t duk_get_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
	return duk_get_prop(thr, obj_idx);
}

DUK_INTERNAL duk_bool_t duk_get_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	return duk_get_prop_stridx(thr, (duk_idx_t) (duk_int16_t) (packed_args >> 16),
	                                (duk_small_uint_t) (packed_args & 0xffffUL));
}

DUK_INTERNAL duk_bool_t duk_get_prop_stridx_boolean(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_bool_t *out_has_prop) {
	duk_bool_t rc;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	rc = duk_get_prop_stridx(thr, obj_idx, stridx);
	if (out_has_prop) {
		*out_has_prop = rc;
	}
	return duk_to_boolean_top_pop(thr);
}

/* This get variant is for internal use, it differs from standard
 * duk_get_prop() in that:
 *   - Object argument must be an object (primitive values not supported).
 *   - Key argument must be a string (no coercion).
 *   - Only own properties are checked (no inheritance).  Only "entry part"
 *     properties are checked (not array index properties).
 *   - Property must be a plain data property, not a getter.
 *   - Proxy traps are not triggered.
 */
DUK_INTERNAL duk_bool_t duk_xget_owndataprop(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_hobject *h_obj;
	duk_hstring *h_key;
	duk_tval *tv_val;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: copying tv_obj and tv_key to locals to shield against a valstack
	 * resize is not necessary for a property get right now.
	 */

	h_obj = duk_get_hobject(thr, obj_idx);
	if (h_obj == NULL) {
		return 0;
	}
	h_key = duk_require_hstring(thr, -1);

	tv_val = duk_hobject_find_entry_tval_ptr(thr->heap, h_obj, h_key);
	if (tv_val == NULL) {
		return 0;
	}

	duk_push_tval(thr, tv_val);
	duk_remove_m2(thr);  /* remove key */

	return 1;
}

DUK_INTERNAL duk_bool_t duk_xget_owndataprop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
	return duk_xget_owndataprop(thr, obj_idx);
}

DUK_INTERNAL duk_bool_t duk_xget_owndataprop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	return duk_xget_owndataprop_stridx(thr, (duk_idx_t) (duk_int16_t) (packed_args >> 16),
	                                   (duk_small_uint_t) (packed_args & 0xffffUL));
}

DUK_LOCAL duk_bool_t duk__put_prop_shared(duk_hthread *thr, duk_idx_t obj_idx, duk_idx_t idx_key) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_tval *tv_val;
	duk_bool_t throw_flag;
	duk_bool_t rc;

	/* Note: copying tv_obj and tv_key to locals to shield against a valstack
	 * resize is not necessary for a property put right now (putprop protects
	 * against it internally).
	 */

	/* Key and value indices are either (-2, -1) or (-1, -2).  Given idx_key,
	 * idx_val is always (idx_key ^ 0x01).
	 */
	DUK_ASSERT((idx_key == -2 && (idx_key ^ 1) == -1) ||
	           (idx_key == -1 && (idx_key ^ 1) == -2));
	/* XXX: Direct access; faster validation. */
	tv_obj = duk_require_tval(thr, obj_idx);
	tv_key = duk_require_tval(thr, idx_key);
	tv_val = duk_require_tval(thr, idx_key ^ 1);
	throw_flag = duk_is_strict_call(thr);

	rc = duk_hobject_putprop(thr, tv_obj, tv_key, tv_val, throw_flag);
	DUK_ASSERT(rc == 0 || rc == 1);

	duk_pop_2(thr);  /* remove key and value */
	return rc;  /* 1 if property found, 0 otherwise */
}

DUK_EXTERNAL duk_bool_t duk_put_prop(duk_hthread *thr, duk_idx_t obj_idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__put_prop_shared(thr, obj_idx, -2);
}

DUK_EXTERNAL duk_bool_t duk_put_prop_string(duk_hthread *thr, duk_idx_t obj_idx, const char *key) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	/* Careful here and with other duk_put_prop_xxx() helpers: the
	 * target object and the property value may be in the same value
	 * stack slot (unusual, but still conceptually clear).
	 */
	obj_idx = duk_normalize_index(thr, obj_idx);
	(void) duk_push_string(thr, key);
	return duk__put_prop_shared(thr, obj_idx, -1);
}

DUK_EXTERNAL duk_bool_t duk_put_prop_lstring(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_normalize_index(thr, obj_idx);
	(void) duk_push_lstring(thr, key, key_len);
	return duk__put_prop_shared(thr, obj_idx, -1);
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_put_prop_literal_raw(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	obj_idx = duk_normalize_index(thr, obj_idx);
	(void) duk_push_literal_raw(thr, key, key_len);
	return duk__put_prop_shared(thr, obj_idx, -1);
}
#endif

DUK_EXTERNAL duk_bool_t duk_put_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_uarridx(thr, arr_idx);
	return duk__put_prop_shared(thr, obj_idx, -1);
}

DUK_EXTERNAL duk_bool_t duk_put_prop_heapptr(duk_hthread *thr, duk_idx_t obj_idx, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_heapptr(thr, ptr);  /* NULL -> 'undefined' */
	return duk__put_prop_shared(thr, obj_idx, -1);
}


DUK_INTERNAL duk_bool_t duk_put_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
	return duk__put_prop_shared(thr, obj_idx, -1);
}

DUK_INTERNAL duk_bool_t duk_put_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	return duk_put_prop_stridx(thr, (duk_idx_t) (duk_int16_t) (packed_args >> 16),
	                                (duk_small_uint_t) (packed_args & 0xffffUL));
}

DUK_EXTERNAL duk_bool_t duk_del_prop(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_bool_t throw_flag;
	duk_bool_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: copying tv_obj and tv_key to locals to shield against a valstack
	 * resize is not necessary for a property delete right now.
	 */

	tv_obj = duk_require_tval(thr, obj_idx);
	tv_key = duk_require_tval(thr, -1);
	throw_flag = duk_is_strict_call(thr);

	rc = duk_hobject_delprop(thr, tv_obj, tv_key, throw_flag);
	DUK_ASSERT(rc == 0 || rc == 1);

	duk_pop(thr);  /* remove key */
	return rc;
}

DUK_EXTERNAL duk_bool_t duk_del_prop_string(duk_hthread *thr, duk_idx_t obj_idx, const char *key) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_string(thr, key);
	return duk_del_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_del_prop_lstring(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_lstring(thr, key, key_len);
	return duk_del_prop(thr, obj_idx);
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_del_prop_literal_raw(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_literal_raw(thr, key, key_len);
	return duk_del_prop(thr, obj_idx);
}
#endif

DUK_EXTERNAL duk_bool_t duk_del_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_uarridx(thr, arr_idx);
	return duk_del_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_del_prop_heapptr(duk_hthread *thr, duk_idx_t obj_idx, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_heapptr(thr, ptr);  /* NULL -> 'undefined' */
	return duk_del_prop(thr, obj_idx);
}

DUK_INTERNAL duk_bool_t duk_del_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
	return duk_del_prop(thr, obj_idx);
}

#if 0
DUK_INTERNAL duk_bool_t duk_del_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	return duk_del_prop_stridx(thr, (duk_idx_t) (duk_int16_t) (packed_args >> 16),
	                                (duk_small_uint_t) (packed_args & 0xffffUL));
}
#endif

DUK_EXTERNAL duk_bool_t duk_has_prop(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_bool_t rc;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: copying tv_obj and tv_key to locals to shield against a valstack
	 * resize is not necessary for a property existence check right now.
	 */

	tv_obj = duk_require_tval(thr, obj_idx);
	tv_key = duk_require_tval(thr, -1);

	rc = duk_hobject_hasprop(thr, tv_obj, tv_key);
	DUK_ASSERT(rc == 0 || rc == 1);

	duk_pop(thr);  /* remove key */
	return rc;  /* 1 if property found, 0 otherwise */
}

DUK_EXTERNAL duk_bool_t duk_has_prop_string(duk_hthread *thr, duk_idx_t obj_idx, const char *key) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_string(thr, key);
	return duk_has_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_has_prop_lstring(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_lstring(thr, key, key_len);
	return duk_has_prop(thr, obj_idx);
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_has_prop_literal_raw(duk_hthread *thr, duk_idx_t obj_idx, const char *key, duk_size_t key_len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_literal_raw(thr, key, key_len);
	return duk_has_prop(thr, obj_idx);
}
#endif

DUK_EXTERNAL duk_bool_t duk_has_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_uarridx(thr, arr_idx);
	return duk_has_prop(thr, obj_idx);
}

DUK_EXTERNAL duk_bool_t duk_has_prop_heapptr(duk_hthread *thr, duk_idx_t obj_idx, void *ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	(void) duk_push_heapptr(thr, ptr);  /* NULL -> 'undefined' */
	return duk_has_prop(thr, obj_idx);
}

DUK_INTERNAL duk_bool_t duk_has_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
	return duk_has_prop(thr, obj_idx);
}

#if 0
DUK_INTERNAL duk_bool_t duk_has_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	return duk_has_prop_stridx(thr, (duk_idx_t) (duk_int16_t) (packed_args >> 16),
	                                (duk_small_uint_t) (packed_args & 0xffffUL));
}
#endif

/* Define own property without inheritance lookups and such.  This differs from
 * [[DefineOwnProperty]] because special behaviors (like Array 'length') are
 * not invoked by this method.  The caller must be careful to invoke any such
 * behaviors if necessary.
 */
DUK_INTERNAL void duk_xdef_prop(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t desc_flags) {
	duk_hobject *obj;
	duk_hstring *key;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, obj_idx);
	DUK_ASSERT(obj != NULL);
	key = duk_to_property_key_hstring(thr, -2);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(duk_require_tval(thr, -1) != NULL);

	duk_hobject_define_property_internal(thr, obj, key, desc_flags);

	duk_pop(thr);  /* pop key */
}

DUK_INTERNAL void duk_xdef_prop_index(duk_hthread *thr, duk_idx_t obj_idx, duk_uarridx_t arr_idx, duk_small_uint_t desc_flags) {
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, obj_idx);
	DUK_ASSERT(obj != NULL);

	duk_hobject_define_property_internal_arridx(thr, obj, arr_idx, desc_flags);
	/* value popped by call */
}

DUK_INTERNAL void duk_xdef_prop_stridx(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_small_uint_t desc_flags) {
	duk_hobject *obj;
	duk_hstring *key;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);

	obj = duk_require_hobject(thr, obj_idx);
	DUK_ASSERT(obj != NULL);
	key = DUK_HTHREAD_GET_STRING(thr, stridx);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(duk_require_tval(thr, -1) != NULL);

	duk_hobject_define_property_internal(thr, obj, key, desc_flags);
	/* value popped by call */
}

DUK_INTERNAL void duk_xdef_prop_stridx_short_raw(duk_hthread *thr, duk_uint_t packed_args) {
	duk_xdef_prop_stridx(thr, (duk_idx_t) (duk_int8_t) (packed_args >> 24),
	                          (duk_small_uint_t) (packed_args >> 8) & 0xffffUL,
	                          (duk_small_uint_t) (packed_args & 0xffL));
}

#if 0  /*unused*/
DUK_INTERNAL void duk_xdef_prop_stridx_builtin(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx, duk_small_int_t builtin_idx, duk_small_uint_t desc_flags) {
	duk_hobject *obj;
	duk_hstring *key;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);
	DUK_ASSERT_BIDX_VALID(builtin_idx);

	obj = duk_require_hobject(thr, obj_idx);
	DUK_ASSERT(obj != NULL);
	key = DUK_HTHREAD_GET_STRING(thr, stridx);
	DUK_ASSERT(key != NULL);

	duk_push_hobject(thr, thr->builtins[builtin_idx]);
	duk_hobject_define_property_internal(thr, obj, key, desc_flags);
	/* value popped by call */
}
#endif

/* This is a rare property helper; it sets the global thrower (E5 Section 13.2.3)
 * setter/getter into an object property.  This is needed by the 'arguments'
 * object creation code, function instance creation code, and Function.prototype.bind().
 */

DUK_INTERNAL void duk_xdef_prop_stridx_thrower(duk_hthread *thr, duk_idx_t obj_idx, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	duk_push_hstring_stridx(thr, stridx);
	duk_push_hobject_bidx(thr, DUK_BIDX_TYPE_ERROR_THROWER);
	duk_dup_top(thr);
	duk_def_prop(thr, obj_idx, DUK_DEFPROP_HAVE_SETTER | DUK_DEFPROP_HAVE_GETTER | DUK_DEFPROP_FORCE);  /* attributes always 0 */
}

/* Object.getOwnPropertyDescriptor() equivalent C binding. */
DUK_EXTERNAL void duk_get_prop_desc(duk_hthread *thr, duk_idx_t obj_idx, duk_uint_t flags) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(flags);  /* no flags defined yet */

	duk_hobject_object_get_own_property_descriptor(thr, obj_idx);  /* [ ... key ] -> [ ... desc ] */
}

/* Object.defineProperty() equivalent C binding. */
DUK_EXTERNAL void duk_def_prop(duk_hthread *thr, duk_idx_t obj_idx, duk_uint_t flags) {
	duk_idx_t idx_base;
	duk_hobject *obj;
	duk_hstring *key;
	duk_idx_t idx_value;
	duk_hobject *get;
	duk_hobject *set;
	duk_uint_t is_data_desc;
	duk_uint_t is_acc_desc;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, obj_idx);

	is_data_desc = flags & (DUK_DEFPROP_HAVE_VALUE | DUK_DEFPROP_HAVE_WRITABLE);
	is_acc_desc = flags & (DUK_DEFPROP_HAVE_GETTER | DUK_DEFPROP_HAVE_SETTER);
	if (is_data_desc && is_acc_desc) {
		/* "Have" flags must not be conflicting so that they would
		 * apply to both a plain property and an accessor at the same
		 * time.
		 */
		goto fail_invalid_desc;
	}

	idx_base = duk_get_top_index(thr);
	if (flags & DUK_DEFPROP_HAVE_SETTER) {
		duk_require_type_mask(thr, idx_base, DUK_TYPE_MASK_UNDEFINED |
		                                     DUK_TYPE_MASK_OBJECT |
		                                     DUK_TYPE_MASK_LIGHTFUNC);
		set = duk_get_hobject_promote_lfunc(thr, idx_base);
		if (set != NULL && !DUK_HOBJECT_IS_CALLABLE(set)) {
			goto fail_not_callable;
		}
		idx_base--;
	} else {
		set = NULL;
	}
	if (flags & DUK_DEFPROP_HAVE_GETTER) {
		duk_require_type_mask(thr, idx_base, DUK_TYPE_MASK_UNDEFINED |
		                                     DUK_TYPE_MASK_OBJECT |
		                                     DUK_TYPE_MASK_LIGHTFUNC);
		get = duk_get_hobject_promote_lfunc(thr, idx_base);
		if (get != NULL && !DUK_HOBJECT_IS_CALLABLE(get)) {
			goto fail_not_callable;
		}
		idx_base--;
	} else {
		get = NULL;
	}
	if (flags & DUK_DEFPROP_HAVE_VALUE) {
		idx_value = idx_base;
		idx_base--;
	} else {
		idx_value = (duk_idx_t) -1;
	}
	key = duk_to_property_key_hstring(thr, idx_base);
	DUK_ASSERT(key != NULL);

	duk_require_valid_index(thr, idx_base);

	duk_hobject_define_property_helper(thr,
	                                   flags /*defprop_flags*/,
	                                   obj,
	                                   key,
	                                   idx_value,
	                                   get,
	                                   set,
	                                   1 /*throw_flag*/);

	/* Clean up stack */

	duk_set_top(thr, idx_base);

	/* [ ... obj ... ] */

	return;

 fail_invalid_desc:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_DESCRIPTOR);
	DUK_WO_NORETURN(return;);

 fail_not_callable:
	DUK_ERROR_TYPE(thr, DUK_STR_NOT_CALLABLE);
	DUK_WO_NORETURN(return;);
}

/*
 *  Object related
 */

DUK_EXTERNAL void duk_compact(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_get_hobject(thr, obj_idx);
	if (obj) {
		/* Note: this may fail, caller should protect the call if necessary */
		duk_hobject_compact_props(thr, obj);
	}
}

DUK_INTERNAL void duk_compact_m1(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_compact(thr, -1);
}

/* XXX: the duk_hobject_enum.c stack APIs should be reworked */

DUK_EXTERNAL void duk_enum(duk_hthread *thr, duk_idx_t obj_idx, duk_uint_t enum_flags) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_dup(thr, obj_idx);
	duk_require_hobject_promote_mask(thr, -1, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	duk_hobject_enumerator_create(thr, enum_flags);   /* [target] -> [enum] */
}

DUK_EXTERNAL duk_bool_t duk_next(duk_hthread *thr, duk_idx_t enum_index, duk_bool_t get_value) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_require_hobject(thr, enum_index);
	duk_dup(thr, enum_index);
	return duk_hobject_enumerator_next(thr, get_value);
}

DUK_INTERNAL void duk_seal_freeze_raw(duk_hthread *thr, duk_idx_t obj_idx, duk_bool_t is_freeze) {
	duk_tval *tv;
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, obj_idx);
	DUK_ASSERT(tv != NULL);

	/* Seal/freeze are quite rare in practice so it'd be nice to get the
	 * correct behavior simply via automatic promotion (at the cost of some
	 * memory churn).  However, the promoted objects don't behave the same,
	 * e.g. promoted lightfuncs are extensible.
	 */

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_BUFFER:
		/* Plain buffer: already sealed, but not frozen (and can't be frozen
		 * because index properties can't be made non-writable.
		 */
		if (is_freeze) {
			goto fail_cannot_freeze;
		}
		break;
	case DUK_TAG_LIGHTFUNC:
		/* Lightfunc: already sealed and frozen, success. */
		break;
	case DUK_TAG_OBJECT:
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (is_freeze && DUK_HOBJECT_IS_BUFOBJ(h)) {
			/* Buffer objects cannot be frozen because there's no internal
			 * support for making virtual array indices non-writable.
			 */
			DUK_DD(DUK_DDPRINT("cannot freeze a buffer object"));
			goto fail_cannot_freeze;
		}
		duk_hobject_object_seal_freeze_helper(thr, h, is_freeze);

		/* Sealed and frozen objects cannot gain any more properties,
		 * so this is a good time to compact them.
		 */
		duk_hobject_compact_props(thr, h);
		break;
	default:
		/* ES2015 Sections 19.1.2.5, 19.1.2.17 */
		break;
	}
	return;

 fail_cannot_freeze:
	DUK_ERROR_TYPE_INVALID_ARGS(thr);  /* XXX: proper error message */
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_seal(duk_hthread *thr, duk_idx_t obj_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_seal_freeze_raw(thr, obj_idx, 0 /*is_freeze*/);
}

DUK_EXTERNAL void duk_freeze(duk_hthread *thr, duk_idx_t obj_idx) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_seal_freeze_raw(thr, obj_idx, 1 /*is_freeze*/);
}

/*
 *  Helpers for writing multiple properties
 */

DUK_EXTERNAL void duk_put_function_list(duk_hthread *thr, duk_idx_t obj_idx, const duk_function_list_entry *funcs) {
	const duk_function_list_entry *ent = funcs;

	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	if (ent != NULL) {
		while (ent->key != NULL) {
			duk_push_c_function(thr, ent->value, ent->nargs);
			duk_put_prop_string(thr, obj_idx, ent->key);
			ent++;
		}
	}
}

DUK_EXTERNAL void duk_put_number_list(duk_hthread *thr, duk_idx_t obj_idx, const duk_number_list_entry *numbers) {
	const duk_number_list_entry *ent = numbers;
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	obj_idx = duk_require_normalize_index(thr, obj_idx);
	if (ent != NULL) {
		while (ent->key != NULL) {
			tv = thr->valstack_top++;
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv));  /* value stack init policy */
			DUK_TVAL_SET_NUMBER_CHKFAST_SLOW(tv, ent->value);  /* no need for decref/incref */
			duk_put_prop_string(thr, obj_idx, ent->key);
			ent++;
		}
	}
}

/*
 *  Shortcut for accessing global object properties
 */

DUK_EXTERNAL duk_bool_t duk_get_global_string(duk_hthread *thr, const char *key) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	ret = duk_get_prop_string(thr, -1, key);
	duk_remove_m2(thr);
	return ret;
}

DUK_EXTERNAL duk_bool_t duk_get_global_lstring(duk_hthread *thr, const char *key, duk_size_t key_len) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	ret = duk_get_prop_lstring(thr, -1, key, key_len);
	duk_remove_m2(thr);
	return ret;
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_get_global_literal_raw(duk_hthread *thr, const char *key, duk_size_t key_len) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	ret = duk_get_prop_literal_raw(thr, -1, key, key_len);
	duk_remove_m2(thr);
	return ret;
}
#endif

DUK_EXTERNAL duk_bool_t duk_get_global_heapptr(duk_hthread *thr, void *ptr) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	ret = duk_get_prop_heapptr(thr, -1, ptr);
	duk_remove_m2(thr);
	return ret;
}


DUK_EXTERNAL duk_bool_t duk_put_global_string(duk_hthread *thr, const char *key) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	duk_insert(thr, -2);
	ret = duk_put_prop_string(thr, -2, key);  /* [ ... global val ] -> [ ... global ] */
	duk_pop(thr);
	return ret;
}

DUK_EXTERNAL duk_bool_t duk_put_global_lstring(duk_hthread *thr, const char *key, duk_size_t key_len) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	duk_insert(thr, -2);
	ret = duk_put_prop_lstring(thr, -2, key, key_len);  /* [ ... global val ] -> [ ... global ] */
	duk_pop(thr);
	return ret;
}

#if !defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL duk_bool_t duk_put_global_literal_raw(duk_hthread *thr, const char *key, duk_size_t key_len) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);
	DUK_ASSERT(key[key_len] == (char) 0);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	duk_insert(thr, -2);
	ret = duk_put_prop_literal_raw(thr, -2, key, key_len);  /* [ ... global val ] -> [ ... global ] */
	duk_pop(thr);
	return ret;
}
#endif

DUK_EXTERNAL duk_bool_t duk_put_global_heapptr(duk_hthread *thr, void *ptr) {
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);

	/* XXX: direct implementation */

	duk_push_hobject(thr, thr->builtins[DUK_BIDX_GLOBAL]);
	duk_insert(thr, -2);
	ret = duk_put_prop_heapptr(thr, -2, ptr);  /* [ ... global val ] -> [ ... global ] */
	duk_pop(thr);
	return ret;
}

/*
 *  ES2015 GetMethod()
 */

DUK_INTERNAL duk_bool_t duk_get_method_stridx(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t stridx) {
	(void) duk_get_prop_stridx(thr, idx, stridx);
	if (duk_is_null_or_undefined(thr, -1)) {
		duk_pop_nodecref_unsafe(thr);
		return 0;
	}
	if (!duk_is_callable(thr, -1)) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CALLABLE);
		DUK_WO_NORETURN(return 0;);
	}
	return 1;
}

/*
 *  Object prototype
 */

DUK_EXTERNAL void duk_get_prototype(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *obj;
	duk_hobject *proto;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, idx);
	DUK_ASSERT(obj != NULL);

	/* XXX: shared helper for duk_push_hobject_or_undefined()? */
	proto = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, obj);
	if (proto) {
		duk_push_hobject(thr, proto);
	} else {
		duk_push_undefined(thr);
	}
}

DUK_EXTERNAL void duk_set_prototype(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *obj;
	duk_hobject *proto;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, idx);
	DUK_ASSERT(obj != NULL);
	duk_require_type_mask(thr, -1, DUK_TYPE_MASK_UNDEFINED |
	                               DUK_TYPE_MASK_OBJECT);
	proto = duk_get_hobject(thr, -1);
	/* proto can also be NULL here (allowed explicitly) */

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);  /* XXX: "read only object"? */
		DUK_WO_NORETURN(return;);
	}
#endif

	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, obj, proto);

	duk_pop(thr);
}

DUK_INTERNAL void duk_clear_prototype(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, idx);
	DUK_ASSERT(obj != NULL);

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);  /* XXX: "read only object"? */
		DUK_WO_NORETURN(return;);
	}
#endif

	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, obj, NULL);
}

DUK_INTERNAL duk_bool_t duk_is_bare_object(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *obj;
	duk_hobject *proto;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_require_hobject(thr, idx);
	DUK_ASSERT(obj != NULL);

	proto = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, obj);
	return (proto == NULL);
}

/*
 *  Object finalizer
 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
/* XXX: these could be implemented as macros calling an internal function
 * directly.
 * XXX: same issue as with Duktape.fin: there's no way to delete the property
 * now (just set it to undefined).
 */
DUK_EXTERNAL void duk_get_finalizer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	/* This get intentionally walks the inheritance chain at present,
	 * which matches how the effective finalizer property is also
	 * looked up in GC.
	 */
	duk_get_prop_stridx(thr, idx, DUK_STRIDX_INT_FINALIZER);
}

DUK_EXTERNAL void duk_set_finalizer(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;
	duk_bool_t callable;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_require_hobject(thr, idx);  /* Get before 'put' so that 'idx' is correct. */
	callable = duk_is_callable(thr, -1);

	/* At present finalizer is stored as a hidden Symbol, with normal
	 * inheritance and access control.  As a result, finalizer cannot
	 * currently be set on a non-extensible (sealed or frozen) object.
	 * It might be useful to allow it.
	 */
	duk_put_prop_stridx(thr, idx, DUK_STRIDX_INT_FINALIZER);

	/* In addition to setting the finalizer property, keep a "have
	 * finalizer" flag in duk_hobject in sync so that refzero can do
	 * a very quick finalizer check by walking the prototype chain
	 * and checking the flag alone.  (Note that this means that just
	 * setting _Finalizer on an object won't affect finalizer checks.)
	 *
	 * NOTE: if the argument is a Proxy object, this flag will be set
	 * on the Proxy, not the target.  As a result, the target won't get
	 * a finalizer flag and the Proxy also won't be finalized as there's
	 * an explicit Proxy check in finalization now.
	 */
	if (callable) {
		DUK_HOBJECT_SET_HAVE_FINALIZER(h);
	} else {
		DUK_HOBJECT_CLEAR_HAVE_FINALIZER(h);
	}
}
#else  /* DUK_USE_FINALIZER_SUPPORT */
DUK_EXTERNAL void duk_get_finalizer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_set_finalizer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(idx);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */
/*
 *  Random numbers
 */

/* #include duk_internal.h -> already included */

DUK_EXTERNAL duk_double_t duk_random(duk_hthread *thr) {
	return (duk_double_t) DUK_UTIL_GET_RANDOM_DOUBLE(thr);
}
/*
 *  API calls related to general value stack manipulation: resizing the value
 *  stack, pushing and popping values, type checking and reading values,
 *  coercing values, etc.
 *
 *  Also contains internal functions (such as duk_get_tval()), defined
 *  in duk_api_internal.h, with semantics similar to the public API.
 */

/* XXX: repetition of stack pre-checks -> helper or macro or inline */
/* XXX: shared api error strings, and perhaps even throw code for rare cases? */

/* #include duk_internal.h -> already included */

/*
 *  Forward declarations
 */

DUK_LOCAL_DECL duk_idx_t duk__push_c_function_raw(duk_hthread *thr, duk_c_function func, duk_idx_t nargs, duk_uint_t flags, duk_small_uint_t proto_bidx);

/*
 *  Global state for working around missing variadic macros
 */

#if !defined(DUK_USE_VARIADIC_MACROS)
DUK_EXTERNAL const char *duk_api_global_filename = NULL;
DUK_EXTERNAL duk_int_t duk_api_global_line = 0;
#endif

/*
 *  Misc helpers
 */

DUK_LOCAL const char * const duk__symbol_type_strings[4] = {
	"hidden", "global", "local", "wellknown"
};

#if !defined(DUK_USE_PACKED_TVAL)
DUK_LOCAL const duk_uint_t duk__type_from_tag[] = {
	DUK_TYPE_NUMBER,
	DUK_TYPE_NUMBER,  /* fastint */
	DUK_TYPE_UNDEFINED,
	DUK_TYPE_NULL,
	DUK_TYPE_BOOLEAN,
	DUK_TYPE_POINTER,
	DUK_TYPE_LIGHTFUNC,
	DUK_TYPE_NONE,
	DUK_TYPE_STRING,
	DUK_TYPE_OBJECT,
	DUK_TYPE_BUFFER,
};
DUK_LOCAL const duk_uint_t duk__type_mask_from_tag[] = {
	DUK_TYPE_MASK_NUMBER,
	DUK_TYPE_MASK_NUMBER,  /* fastint */
	DUK_TYPE_MASK_UNDEFINED,
	DUK_TYPE_MASK_NULL,
	DUK_TYPE_MASK_BOOLEAN,
	DUK_TYPE_MASK_POINTER,
	DUK_TYPE_MASK_LIGHTFUNC,
	DUK_TYPE_MASK_NONE,
	DUK_TYPE_MASK_STRING,
	DUK_TYPE_MASK_OBJECT,
	DUK_TYPE_MASK_BUFFER,
};
#endif  /* !DUK_USE_PACKED_TVAL */

/* Assert that there's room for one value. */
#define DUK__ASSERT_SPACE() do { \
		DUK_ASSERT(!(thr->valstack_top >= thr->valstack_end)); \
	} while (0)

/* Check that there's room to push one value. */
#if defined(DUK_USE_VALSTACK_UNSAFE)
/* Faster but value stack overruns are memory unsafe. */
#define DUK__CHECK_SPACE() DUK__ASSERT_SPACE()
#else
#define DUK__CHECK_SPACE() do { \
		if (DUK_UNLIKELY(thr->valstack_top >= thr->valstack_end)) { \
			DUK_ERROR_RANGE_PUSH_BEYOND(thr); \
		} \
	} while (0)
#endif

DUK_LOCAL duk_small_uint_t duk__get_symbol_type(duk_hstring *h) {
	const duk_uint8_t *data;
	duk_size_t len;

	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HSTRING_HAS_SYMBOL(h));
	DUK_ASSERT(DUK_HSTRING_GET_BYTELEN(h) >= 1);  /* always true, symbol prefix */

	data = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	len = DUK_HSTRING_GET_BYTELEN(h);
	DUK_ASSERT(len >= 1);

	/* XXX: differentiate between 0x82 and 0xff (hidden vs. internal?)? */

	if (data[0] == 0xffU) {
		return DUK_SYMBOL_TYPE_HIDDEN;
	} else if (data[0] == 0x82U) {
		return DUK_SYMBOL_TYPE_HIDDEN;
	} else if (data[0] == 0x80U) {
		return DUK_SYMBOL_TYPE_GLOBAL;
	} else if (data[len - 1] != 0xffU) {
		return DUK_SYMBOL_TYPE_LOCAL;
	} else {
		return DUK_SYMBOL_TYPE_WELLKNOWN;
	}
}

DUK_LOCAL const char *duk__get_symbol_type_string(duk_hstring *h) {
	duk_small_uint_t idx;
	idx = duk__get_symbol_type(h);
	DUK_ASSERT(idx < sizeof(duk__symbol_type_strings));
	return duk__symbol_type_strings[idx];
}

DUK_LOCAL_DECL duk_heaphdr *duk__get_tagged_heaphdr_raw(duk_hthread *thr, duk_idx_t idx, duk_uint_t tag);

DUK_LOCAL duk_int_t duk__api_coerce_d2i(duk_hthread *thr, duk_idx_t idx, duk_int_t def_value, duk_bool_t require) {
	duk_tval *tv;
	duk_small_int_t c;
	duk_double_t d;

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	/*
	 *  Special cases like NaN and +/- Infinity are handled explicitly
	 *  because a plain C coercion from double to int handles these cases
	 *  in undesirable ways.  For instance, NaN may coerce to INT_MIN
	 *  (not zero), and INT_MAX + 1 may coerce to INT_MIN (not INT_MAX).
	 *
	 *  This double-to-int coercion differs from ToInteger() because it
	 *  has a finite range (ToInteger() allows e.g. +/- Infinity).  It
	 *  also differs from ToInt32() because the INT_MIN/INT_MAX clamping
	 *  depends on the size of the int type on the platform.  In particular,
	 *  on platforms with a 64-bit int type, the full range is allowed.
	 */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		duk_int64_t t = DUK_TVAL_GET_FASTINT(tv);
#if (DUK_INT_MAX <= 0x7fffffffL)
		/* Clamping only necessary for 32-bit ints. */
		if (t < DUK_INT_MIN) {
			t = DUK_INT_MIN;
		} else if (t > DUK_INT_MAX) {
			t = DUK_INT_MAX;
		}
#endif
		return (duk_int_t) t;
	}
#endif

	if (DUK_TVAL_IS_NUMBER(tv)) {
		d = DUK_TVAL_GET_NUMBER(tv);
		c = (duk_small_int_t) DUK_FPCLASSIFY(d);
		if (c == DUK_FP_NAN) {
			return 0;
		} else if (d < (duk_double_t) DUK_INT_MIN) {
			/* covers -Infinity */
			return DUK_INT_MIN;
		} else if (d > (duk_double_t) DUK_INT_MAX) {
			/* covers +Infinity */
			return DUK_INT_MAX;
		} else {
			/* coerce towards zero */
			return (duk_int_t) d;
		}
	}

	if (require) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "number", DUK_STR_NOT_NUMBER);
		DUK_WO_NORETURN(return 0;);
	}

	return def_value;
}

DUK_LOCAL duk_uint_t duk__api_coerce_d2ui(duk_hthread *thr, duk_idx_t idx, duk_uint_t def_value, duk_bool_t require) {
	duk_tval *tv;
	duk_small_int_t c;
	duk_double_t d;

	/* Same as above but for unsigned int range. */

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		duk_int64_t t = DUK_TVAL_GET_FASTINT(tv);
		if (t < 0) {
			t = 0;
		}
#if (DUK_UINT_MAX <= 0xffffffffUL)
		/* Clamping only necessary for 32-bit ints. */
		else if (t > DUK_UINT_MAX) {
			t = DUK_UINT_MAX;
		}
#endif
		return (duk_uint_t) t;
	}
#endif

	if (DUK_TVAL_IS_NUMBER(tv)) {
		d = DUK_TVAL_GET_NUMBER(tv);
		c = (duk_small_int_t) DUK_FPCLASSIFY(d);
		if (c == DUK_FP_NAN) {
			return 0;
		} else if (d < 0.0) {
			/* covers -Infinity */
			return (duk_uint_t) 0;
		} else if (d > (duk_double_t) DUK_UINT_MAX) {
			/* covers +Infinity */
			return (duk_uint_t) DUK_UINT_MAX;
		} else {
			/* coerce towards zero */
			return (duk_uint_t) d;
		}
	}

	if (require) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "number", DUK_STR_NOT_NUMBER);
		DUK_WO_NORETURN(return 0;);
	}

	return def_value;
}

/*
 *  Stack index validation/normalization and getting a stack duk_tval ptr.
 *
 *  These are called by many API entrypoints so the implementations must be
 *  fast and "inlined".
 *
 *  There's some repetition because of this; keep the functions in sync.
 */

DUK_EXTERNAL duk_idx_t duk_normalize_index(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t vs_size;
	duk_uidx_t uidx;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	/* Care must be taken to avoid pointer wrapping in the index
	 * validation.  For instance, on a 32-bit platform with 8-byte
	 * duk_tval the index 0x20000000UL would wrap the memory space
	 * once.
	 */

	/* Assume value stack sizes (in elements) fits into duk_idx_t. */
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT_DISABLE(vs_size >= 0);  /* unsigned */

	if (idx < 0) {
		uidx = vs_size + (duk_uidx_t) idx;
	} else {
		/* since index non-negative */
		DUK_ASSERT(idx != DUK_INVALID_INDEX);
		uidx = (duk_uidx_t) idx;
	}

	/* DUK_INVALID_INDEX won't be accepted as a valid index. */
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_size);

	if (DUK_LIKELY(uidx < vs_size)) {
		return (duk_idx_t) uidx;
	}
	return DUK_INVALID_INDEX;
}

DUK_EXTERNAL duk_idx_t duk_require_normalize_index(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t vs_size;
	duk_uidx_t uidx;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT_DISABLE(vs_size >= 0);  /* unsigned */

	if (idx < 0) {
		uidx = vs_size + (duk_uidx_t) idx;
	} else {
		DUK_ASSERT(idx != DUK_INVALID_INDEX);
		uidx = (duk_uidx_t) idx;
	}

	/* DUK_INVALID_INDEX won't be accepted as a valid index. */
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_size);

	if (DUK_LIKELY(uidx < vs_size)) {
		return (duk_idx_t) uidx;
	}
	DUK_ERROR_RANGE_INDEX(thr, idx);
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_tval *duk_get_tval(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t vs_size;
	duk_uidx_t uidx;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT_DISABLE(vs_size >= 0);  /* unsigned */

	if (idx < 0) {
		uidx = vs_size + (duk_uidx_t) idx;
	} else {
		DUK_ASSERT(idx != DUK_INVALID_INDEX);
		uidx = (duk_uidx_t) idx;
	}

	/* DUK_INVALID_INDEX won't be accepted as a valid index. */
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_size);

	if (DUK_LIKELY(uidx < vs_size)) {
		return thr->valstack_bottom + uidx;
	}
	return NULL;
}

/* Variant of duk_get_tval() which is guaranteed to return a valid duk_tval
 * pointer.  When duk_get_tval() would return NULL, this variant returns a
 * pointer to a duk_tval with tag DUK_TAG_UNUSED.  This allows the call site
 * to avoid an unnecessary NULL check which sometimes leads to better code.
 * The return duk_tval is read only (at least for the UNUSED value).
 */
DUK_LOCAL const duk_tval_unused duk__const_tval_unused = DUK_TVAL_UNUSED_INITIALIZER();

DUK_INTERNAL duk_tval *duk_get_tval_or_unused(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval(thr, idx);
	if (tv != NULL) {
		return tv;
	}
	return (duk_tval *) DUK_LOSE_CONST(&duk__const_tval_unused);
}

DUK_INTERNAL duk_tval *duk_require_tval(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t vs_size;
	duk_uidx_t uidx;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT_DISABLE(vs_size >= 0);  /* unsigned */

	/* Use unsigned arithmetic to optimize comparison. */
	if (idx < 0) {
		uidx = vs_size + (duk_uidx_t) idx;
	} else {
		DUK_ASSERT(idx != DUK_INVALID_INDEX);
		uidx = (duk_uidx_t) idx;
	}

	/* DUK_INVALID_INDEX won't be accepted as a valid index. */
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_size);

	if (DUK_LIKELY(uidx < vs_size)) {
		return thr->valstack_bottom + uidx;
	}
	DUK_ERROR_RANGE_INDEX(thr, idx);
	DUK_WO_NORETURN(return NULL;);
}

/* Non-critical. */
DUK_EXTERNAL duk_bool_t duk_is_valid_index(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	return (duk_normalize_index(thr, idx) >= 0);
}

/* Non-critical. */
DUK_EXTERNAL void duk_require_valid_index(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	if (DUK_UNLIKELY(duk_normalize_index(thr, idx) < 0)) {
		DUK_ERROR_RANGE_INDEX(thr, idx);
		DUK_WO_NORETURN(return;);
	}
}

/*
 *  Value stack top handling
 */

DUK_EXTERNAL duk_idx_t duk_get_top(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
}

/* Internal helper to get current top but to require a minimum top value
 * (TypeError if not met).
 */
DUK_INTERNAL duk_idx_t duk_get_top_require_min(duk_hthread *thr, duk_idx_t min_top) {
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	if (DUK_UNLIKELY(ret < min_top)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return 0;);
	}
	return ret;
}

/* Set stack top within currently allocated range, but don't reallocate.
 * This is performance critical especially for call handling, so whenever
 * changing, profile and look at generated code.
 */
DUK_EXTERNAL void duk_set_top(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t vs_size;
	duk_uidx_t vs_limit;
	duk_uidx_t uidx;
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_INVALID_INDEX < 0);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_bottom);
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);
	vs_limit = (duk_uidx_t) (thr->valstack_end - thr->valstack_bottom);

	if (idx < 0) {
		/* Negative indices are always within allocated stack but
		 * must not go below zero index.
		 */
		uidx = vs_size + (duk_uidx_t) idx;
	} else {
		/* Positive index can be higher than valstack top but must
		 * not go above allocated stack (equality is OK).
		 */
		uidx = (duk_uidx_t) idx;
	}

	/* DUK_INVALID_INDEX won't be accepted as a valid index. */
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_size);
	DUK_ASSERT(vs_size + (duk_uidx_t) DUK_INVALID_INDEX >= vs_limit);

#if defined(DUK_USE_VALSTACK_UNSAFE)
	DUK_ASSERT(uidx <= vs_limit);
	DUK_UNREF(vs_limit);
#else
	if (DUK_UNLIKELY(uidx > vs_limit)) {
		DUK_ERROR_RANGE_INDEX(thr, idx);
		DUK_WO_NORETURN(return;);
	}
#endif
	DUK_ASSERT(uidx <= vs_limit);

	/* Handle change in value stack top.  Respect value stack
	 * initialization policy: 'undefined' above top.  Note that
	 * DECREF may cause a side effect that reallocates valstack,
	 * so must relookup after DECREF.
	 */

	if (uidx >= vs_size) {
		/* Stack size increases or stays the same. */
#if defined(DUK_USE_ASSERTIONS)
		duk_uidx_t count;

		count = uidx - vs_size;
		while (count != 0) {
			count--;
			tv = thr->valstack_top + count;
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv));
		}
#endif
		thr->valstack_top = thr->valstack_bottom + uidx;
	} else {
		/* Stack size decreases. */
#if defined(DUK_USE_REFERENCE_COUNTING)
		duk_uidx_t count;
		duk_tval *tv_end;

		count = vs_size - uidx;
		DUK_ASSERT(count > 0);
		tv = thr->valstack_top;
		tv_end = tv - count;
		DUK_ASSERT(tv > tv_end);  /* Because count > 0. */
		do {
			tv--;
			DUK_ASSERT(tv >= thr->valstack_bottom);
			DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, tv);
		} while (tv != tv_end);
		thr->valstack_top = tv_end;
		DUK_REFZERO_CHECK_FAST(thr);
#else  /* DUK_USE_REFERENCE_COUNTING */
		duk_uidx_t count;
		duk_tval *tv_end;

		count = vs_size - uidx;
		tv = thr->valstack_top;
		tv_end = tv - count;
		DUK_ASSERT(tv > tv_end);
		do {
			tv--;
			DUK_TVAL_SET_UNDEFINED(tv);
		} while (tv != tv_end);
		thr->valstack_top = tv_end;
#endif  /* DUK_USE_REFERENCE_COUNTING */
	}
}

/* Internal variant with a non-negative index and no runtime size checks. */
#if defined(DUK_USE_PREFER_SIZE)
DUK_INTERNAL void duk_set_top_unsafe(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_set_top(thr, idx);
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_INTERNAL void duk_set_top_unsafe(duk_hthread *thr, duk_idx_t idx) {
	duk_uidx_t uidx;
	duk_uidx_t vs_size;
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_bottom);
	DUK_ASSERT(idx >= 0);
	DUK_ASSERT(idx <= (duk_idx_t) (thr->valstack_end - thr->valstack_bottom));

	/* XXX: byte arithmetic */
	uidx = (duk_uidx_t) idx;
	vs_size = (duk_uidx_t) (thr->valstack_top - thr->valstack_bottom);

	if (uidx >= vs_size) {
		/* Stack size increases or stays the same. */
#if defined(DUK_USE_ASSERTIONS)
		duk_uidx_t count;

		count = uidx - vs_size;
		while (count != 0) {
			count--;
			tv = thr->valstack_top + count;
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv));
		}
#endif
		thr->valstack_top = thr->valstack_bottom + uidx;
	} else {
		/* Stack size decreases. */
#if defined(DUK_USE_REFERENCE_COUNTING)
		duk_uidx_t count;
		duk_tval *tv_end;

		count = vs_size - uidx;
		DUK_ASSERT(count > 0);
		tv = thr->valstack_top;
		tv_end = tv - count;
		DUK_ASSERT(tv > tv_end);  /* Because count > 0. */
		do {
			tv--;
			DUK_ASSERT(tv >= thr->valstack_bottom);
			DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, tv);
		} while (tv != tv_end);
		thr->valstack_top = tv_end;
		DUK_REFZERO_CHECK_FAST(thr);
#else  /* DUK_USE_REFERENCE_COUNTING */
		duk_uidx_t count;
		duk_tval *tv_end;

		count = vs_size - uidx;
		tv = thr->valstack_top;
		tv_end = tv - count;
		DUK_ASSERT(tv > tv_end);
		do {
			tv--;
			DUK_TVAL_SET_UNDEFINED(tv);
		} while (tv != tv_end);
		thr->valstack_top = tv_end;
#endif  /* DUK_USE_REFERENCE_COUNTING */
	}
}
#endif  /* DUK_USE_PREFER_SIZE */

/* Internal helper: set top to 'top', and set [idx_wipe_start,top[ to
 * 'undefined' (doing nothing if idx_wipe_start == top).  Indices are
 * positive and within value stack reserve.  This is used by call handling.
 */
DUK_INTERNAL void duk_set_top_and_wipe(duk_hthread *thr, duk_idx_t top, duk_idx_t idx_wipe_start) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(top >= 0);
	DUK_ASSERT(idx_wipe_start >= 0);
	DUK_ASSERT(idx_wipe_start <= top);
	DUK_ASSERT(thr->valstack_bottom + top <= thr->valstack_end);
	DUK_ASSERT(thr->valstack_bottom + idx_wipe_start <= thr->valstack_end);

	duk_set_top_unsafe(thr, idx_wipe_start);
	duk_set_top_unsafe(thr, top);
}

DUK_EXTERNAL duk_idx_t duk_get_top_index(duk_hthread *thr) {
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom) - 1;
	if (DUK_UNLIKELY(ret < 0)) {
		/* Return invalid index; if caller uses this without checking
		 * in another API call, the index won't map to a valid stack
		 * entry.
		 */
		return DUK_INVALID_INDEX;
	}
	return ret;
}

/* Internal variant: call assumes there is at least one element on the value
 * stack frame; this is only asserted for.
 */
DUK_INTERNAL duk_idx_t duk_get_top_index_unsafe(duk_hthread *thr) {
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom) - 1;
	return ret;
}

DUK_EXTERNAL duk_idx_t duk_require_top_index(duk_hthread *thr) {
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom) - 1;
	if (DUK_UNLIKELY(ret < 0)) {
		DUK_ERROR_RANGE_INDEX(thr, -1);
		DUK_WO_NORETURN(return 0;);
	}
	return ret;
}

/*
 *  Value stack resizing.
 *
 *  This resizing happens above the current "top": the value stack can be
 *  grown or shrunk, but the "top" is not affected.  The value stack cannot
 *  be resized to a size below the current reserve.
 *
 *  The low level reallocation primitive must carefully recompute all value
 *  stack pointers, and must also work if ALL pointers are NULL.  The resize
 *  is quite tricky because the valstack realloc may cause a mark-and-sweep,
 *  which may run finalizers.  Running finalizers may resize the valstack
 *  recursively (the same value stack we're working on).  So, after realloc
 *  returns, we know that the valstack bottom, top, and reserve should still
 *  be the same (there should not be live values above the "top"), but its
 *  underlying size, alloc_end, and base pointer may have changed.
 *
 *  'new_size' is known to be <= DUK_USE_VALSTACK_LIMIT, which ensures that
 *  size_t and pointer arithmetic won't wrap in duk__resize_valstack().
 */

/* Low level valstack resize primitive, used for both grow and shrink.  All
 * adjustments for slack etc have already been done.  Doesn't throw but does
 * have allocation side effects.
 */
DUK_LOCAL DUK_COLD DUK_NOINLINE duk_bool_t duk__resize_valstack(duk_hthread *thr, duk_size_t new_size) {
	duk_tval *pre_valstack;
	duk_tval *pre_bottom;
	duk_tval *pre_top;
	duk_tval *pre_end;
	duk_tval *pre_alloc_end;
	duk_ptrdiff_t ptr_diff;
	duk_tval *new_valstack;
	duk_size_t new_alloc_size;
	duk_tval *tv_prev_alloc_end;
	duk_tval *p;

	DUK_HTHREAD_ASSERT_VALID(thr);
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack_end);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack) <= new_size);  /* can't resize below 'top' */
	DUK_ASSERT(new_size <= DUK_USE_VALSTACK_LIMIT);  /* valstack limit caller has check, prevents wrapping */
	DUK_ASSERT(new_size <= DUK_SIZE_MAX / sizeof(duk_tval));  /* specific assert for wrapping */

	/* Pre-realloc pointer copies for asserts and debug logs. */
	pre_valstack = thr->valstack;
	pre_bottom = thr->valstack_bottom;
	pre_top = thr->valstack_top;
	pre_end = thr->valstack_end;
	pre_alloc_end = thr->valstack_alloc_end;

	DUK_UNREF(pre_valstack);
	DUK_UNREF(pre_bottom);
	DUK_UNREF(pre_top);
	DUK_UNREF(pre_end);
	DUK_UNREF(pre_alloc_end);

	/* If finalizer torture enabled, force base pointer change every time
	 * when it would be allowed.
	 */
#if defined(DUK_USE_FINALIZER_TORTURE)
	if (thr->heap->pf_prevent_count == 0) {
		duk_hthread_valstack_torture_realloc(thr);
	}
#endif

	/* Allocate a new valstack using DUK_REALLOC_DIRECT() to deal with
	 * a side effect changing the base pointer.
	 */
	new_alloc_size = sizeof(duk_tval) * new_size;
	new_valstack = (duk_tval *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_valstack_ptr, (void *) thr, new_alloc_size);
	if (DUK_UNLIKELY(new_valstack == NULL)) {
		/* Because new_size != 0, if condition doesn't need to be
		 * (new_valstack != NULL || new_size == 0).
		 */
		DUK_ASSERT(new_size != 0);
		DUK_D(DUK_DPRINT("failed to resize valstack to %lu entries (%lu bytes)",
		                 (unsigned long) new_size, (unsigned long) new_alloc_size));
		return 0;
	}

	/* Debug log any changes in pointer(s) by side effects.  These don't
	 * necessarily imply any incorrect behavior, but should be rare in
	 * practice.
	 */
#if defined(DUK_USE_DEBUG)
	if (thr->valstack != pre_valstack) {
		DUK_D(DUK_DPRINT("valstack base pointer changed during valstack resize: %p -> %p",
		                 (void *) pre_valstack, (void *) thr->valstack));
	}
	if (thr->valstack_bottom != pre_bottom) {
		DUK_D(DUK_DPRINT("valstack bottom pointer changed during valstack resize: %p -> %p",
		                 (void *) pre_bottom, (void *) thr->valstack_bottom));
	}
	if (thr->valstack_top != pre_top) {
		DUK_D(DUK_DPRINT("valstack top pointer changed during valstack resize: %p -> %p",
		                 (void *) pre_top, (void *) thr->valstack_top));
	}
	if (thr->valstack_end != pre_end) {
		DUK_D(DUK_DPRINT("valstack end pointer changed during valstack resize: %p -> %p",
		                 (void *) pre_end, (void *) thr->valstack_end));
	}
	if (thr->valstack_alloc_end != pre_alloc_end) {
		DUK_D(DUK_DPRINT("valstack alloc_end pointer changed during valstack resize: %p -> %p",
		                 (void *) pre_alloc_end, (void *) thr->valstack_alloc_end));
	}
#endif

	/* Assertions: offsets for bottom, top, and end (reserve) must not
	 * have changed even with side effects because they are always
	 * restored in unwind.  For alloc_end there's no guarantee: it may
	 * have grown or shrunk (but remain above 'end').
	 */
	DUK_ASSERT(thr->valstack_bottom - thr->valstack == pre_bottom - pre_valstack);
	DUK_ASSERT(thr->valstack_top - thr->valstack == pre_top - pre_valstack);
	DUK_ASSERT(thr->valstack_end - thr->valstack == pre_end - pre_valstack);
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack_end);

	/* Write new pointers.  Most pointers can be handled as a pointer
	 * difference.
	 */
	ptr_diff = (duk_ptrdiff_t) ((duk_uint8_t *) new_valstack - (duk_uint8_t *) thr->valstack);
	tv_prev_alloc_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_alloc_end + ptr_diff);
	thr->valstack = new_valstack;
	thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_bottom + ptr_diff);
	thr->valstack_top = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_top + ptr_diff);
	thr->valstack_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_end + ptr_diff);
	thr->valstack_alloc_end = (duk_tval *) (void *) ((duk_uint8_t *) new_valstack + new_alloc_size);

	/* Assertions: pointer sanity after pointer updates. */
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack_end);

	DUK_D(DUK_DPRINT("resized valstack %lu -> %lu elements (%lu -> %lu bytes): "
	                 "base=%p -> %p, bottom=%p -> %p (%ld), top=%p -> %p (%ld), "
	                 "end=%p -> %p (%ld), alloc_end=%p -> %p (%ld);"
	                 " tv_prev_alloc_end=%p (-> %ld inits; <0 means shrink)",
	                 (unsigned long) (pre_alloc_end - pre_valstack),
	                 (unsigned long) new_size,
	                 (unsigned long) ((duk_uint8_t *) pre_alloc_end - (duk_uint8_t *) pre_valstack),
	                 (unsigned long) new_alloc_size,
	                 (void *) pre_valstack, (void *) thr->valstack,
	                 (void *) pre_bottom, (void *) thr->valstack_bottom, (long) (thr->valstack_bottom - thr->valstack),
	                 (void *) pre_top, (void *) thr->valstack_top, (long) (thr->valstack_top - thr->valstack),
	                 (void *) pre_end, (void *) thr->valstack_end, (long) (thr->valstack_end - thr->valstack),
	                 (void *) pre_alloc_end, (void *) thr->valstack_alloc_end, (long) (thr->valstack_alloc_end - thr->valstack),
	                 (void *) tv_prev_alloc_end, (long) (thr->valstack_alloc_end - tv_prev_alloc_end)));

	/* If allocation grew, init any new slots to 'undefined'. */
	p = tv_prev_alloc_end;
	while (p < thr->valstack_alloc_end) {
		/* Never executed if new size is smaller. */
		DUK_TVAL_SET_UNDEFINED(p);
		p++;
	}

	/* Assert for value stack initialization policy. */
#if defined(DUK_USE_ASSERTIONS)
	p = thr->valstack_top;
	while (p < thr->valstack_alloc_end) {
		DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(p));
		p++;
	}
#endif

	return 1;
}

DUK_LOCAL DUK_COLD DUK_NOINLINE duk_bool_t duk__valstack_grow(duk_hthread *thr, duk_size_t min_bytes, duk_bool_t throw_on_error) {
	duk_size_t min_size;
	duk_size_t new_size;

	DUK_ASSERT(min_bytes / sizeof(duk_tval) * sizeof(duk_tval) == min_bytes);
	min_size = min_bytes / sizeof(duk_tval);  /* from bytes to slots */

#if defined(DUK_USE_VALSTACK_GROW_SHIFT)
	/* New size is minimum size plus a proportional slack, e.g. shift of
	 * 2 means a 25% slack.
	 */
	new_size = min_size + (min_size >> DUK_USE_VALSTACK_GROW_SHIFT);
#else
	/* New size is tight with no slack.  This is sometimes preferred in
	 * low memory environments.
	 */
	new_size = min_size;
#endif

	if (DUK_UNLIKELY(new_size > DUK_USE_VALSTACK_LIMIT || new_size < min_size /*wrap*/)) {
		/* Note: may be triggered even if minimal new_size would not reach the limit,
		 * plan limit accordingly.
		 */
		if (throw_on_error) {
			DUK_ERROR_RANGE(thr, DUK_STR_VALSTACK_LIMIT);
			DUK_WO_NORETURN(return 0;);
		}
		return 0;
	}

	if (duk__resize_valstack(thr, new_size) == 0) {
		if (throw_on_error) {
			DUK_ERROR_ALLOC_FAILED(thr);
			DUK_WO_NORETURN(return 0;);
		}
		return 0;
	}

	thr->valstack_end = thr->valstack + min_size;
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack_end);

	return 1;
}

/* Hot, inlined value stack grow check.  Because value stack almost never
 * grows, the actual resize call is in a NOINLINE helper.
 */
DUK_INTERNAL DUK_INLINE void duk_valstack_grow_check_throw(duk_hthread *thr, duk_size_t min_bytes) {
	duk_tval *tv;

	tv = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + min_bytes);
	if (DUK_LIKELY(thr->valstack_end >= tv)) {
		return;
	}
	if (DUK_LIKELY(thr->valstack_alloc_end >= tv)) {
		/* Values in [valstack_top,valstack_alloc_end[ are initialized
		 * to 'undefined' so we can just move the end pointer.
		 */
		thr->valstack_end = tv;
		return;
	}
	(void) duk__valstack_grow(thr, min_bytes, 1 /*throw_on_error*/);
}

/* Hot, inlined value stack grow check which doesn't throw. */
DUK_INTERNAL DUK_INLINE duk_bool_t duk_valstack_grow_check_nothrow(duk_hthread *thr, duk_size_t min_bytes) {
	duk_tval *tv;

	tv = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + min_bytes);
	if (DUK_LIKELY(thr->valstack_end >= tv)) {
		return 1;
	}
	if (DUK_LIKELY(thr->valstack_alloc_end >= tv)) {
		thr->valstack_end = tv;
		return 1;
	}
	return duk__valstack_grow(thr, min_bytes, 0 /*throw_on_error*/);
}

/* Value stack shrink check, called from mark-and-sweep. */
DUK_INTERNAL void duk_valstack_shrink_check_nothrow(duk_hthread *thr, duk_bool_t snug) {
	duk_size_t alloc_bytes;
	duk_size_t reserve_bytes;
	duk_size_t shrink_bytes;

	alloc_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_alloc_end - (duk_uint8_t *) thr->valstack);
	reserve_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
	DUK_ASSERT(alloc_bytes >= reserve_bytes);

	/* We're free to shrink the value stack allocation down to
	 * reserve_bytes but not more.  If 'snug' (emergency GC)
	 * shrink whatever we can.  Otherwise only shrink if the new
	 * size would be considerably smaller.
	 */

#if defined(DUK_USE_VALSTACK_SHRINK_CHECK_SHIFT)
	if (snug) {
		shrink_bytes = reserve_bytes;
	} else {
		duk_size_t proportion, slack;

		/* Require that value stack shrinks by at least X% of its
		 * current size.  For example, shift of 2 means at least
		 * 25%.  The proportion is computed as bytes and may not
		 * be a multiple of sizeof(duk_tval); that's OK here.
		 */
		proportion = alloc_bytes >> DUK_USE_VALSTACK_SHRINK_CHECK_SHIFT;
		if (alloc_bytes - reserve_bytes < proportion) {
			/* Too little would be freed, do nothing. */
			return;
		}

		/* Keep a slack after shrinking.  The slack is again a
		 * proportion of the current size (the proportion should
		 * of course be smaller than the check proportion above).
		 */
#if defined(DUK_USE_VALSTACK_SHRINK_SLACK_SHIFT)
		DUK_ASSERT(DUK_USE_VALSTACK_SHRINK_SLACK_SHIFT > DUK_USE_VALSTACK_SHRINK_CHECK_SHIFT);
		slack = alloc_bytes >> DUK_USE_VALSTACK_SHRINK_SLACK_SHIFT;
#else
		slack = 0;
#endif
		shrink_bytes = reserve_bytes +
		               slack / sizeof(duk_tval) * sizeof(duk_tval);  /* multiple of duk_tval */
	}
#else  /* DUK_USE_VALSTACK_SHRINK_CHECK_SHIFT */
	/* Always snug, useful in some low memory environments. */
	DUK_UNREF(snug);
	shrink_bytes = reserve_bytes;
#endif  /* DUK_USE_VALSTACK_SHRINK_CHECK_SHIFT */

	DUK_D(DUK_DPRINT("valstack shrink check: alloc_bytes=%ld, reserve_bytes=%ld, shrink_bytes=%ld (unvalidated)",
	                 (long) alloc_bytes, (long) reserve_bytes, (long) shrink_bytes));
	DUK_ASSERT(shrink_bytes >= reserve_bytes);
	if (shrink_bytes >= alloc_bytes) {
		/* Skip if shrink target is same as current one (or higher,
		 * though that shouldn't happen in practice).
		 */
		return;
	}
	DUK_ASSERT(shrink_bytes / sizeof(duk_tval) * sizeof(duk_tval) == shrink_bytes);

	DUK_D(DUK_DPRINT("valstack shrink check: decided to shrink, snug: %ld", (long) snug));

	duk__resize_valstack(thr, shrink_bytes / sizeof(duk_tval));
}

DUK_EXTERNAL duk_bool_t duk_check_stack(duk_hthread *thr, duk_idx_t extra) {
	duk_size_t min_new_bytes;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr != NULL);

	if (DUK_UNLIKELY(extra < 0 || extra > DUK_USE_VALSTACK_LIMIT)) {
		if (extra < 0) {
			/* Clamping to zero makes the API more robust to calling code
			 * calculation errors.
			 */
			extra = 0;
		} else {
			/* Cause grow check to fail without wrapping arithmetic. */
			extra = DUK_USE_VALSTACK_LIMIT;
		}
	}

	min_new_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) thr->valstack) +
	                sizeof(duk_tval) * ((duk_size_t) extra + DUK_VALSTACK_INTERNAL_EXTRA);
	return duk_valstack_grow_check_nothrow(thr, min_new_bytes);
}

DUK_EXTERNAL void duk_require_stack(duk_hthread *thr, duk_idx_t extra) {
	duk_size_t min_new_bytes;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr != NULL);

	if (DUK_UNLIKELY(extra < 0 || extra > DUK_USE_VALSTACK_LIMIT)) {
		if (extra < 0) {
			/* Clamping to zero makes the API more robust to calling code
			 * calculation errors.
			 */
			extra = 0;
		} else {
			/* Cause grow check to fail without wrapping arithmetic. */
			extra = DUK_USE_VALSTACK_LIMIT;
		}
	}

	min_new_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) thr->valstack) +
	                sizeof(duk_tval) * ((duk_size_t) extra + DUK_VALSTACK_INTERNAL_EXTRA);
	duk_valstack_grow_check_throw(thr, min_new_bytes);
}

DUK_EXTERNAL duk_bool_t duk_check_stack_top(duk_hthread *thr, duk_idx_t top) {
	duk_size_t min_new_bytes;

	DUK_ASSERT_API_ENTRY(thr);

	if (DUK_UNLIKELY(top < 0 || top > DUK_USE_VALSTACK_LIMIT)) {
		if (top < 0) {
			/* Clamping to zero makes the API more robust to calling code
			 * calculation errors.
			 */
			top = 0;
		} else {
			/* Cause grow check to fail without wrapping arithmetic. */
			top = DUK_USE_VALSTACK_LIMIT;
		}
	}

	DUK_ASSERT(top >= 0);
	min_new_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) +
	                sizeof(duk_tval) * ((duk_size_t) top + DUK_VALSTACK_INTERNAL_EXTRA);
	return duk_valstack_grow_check_nothrow(thr, min_new_bytes);
}

DUK_EXTERNAL void duk_require_stack_top(duk_hthread *thr, duk_idx_t top) {
	duk_size_t min_new_bytes;

	DUK_ASSERT_API_ENTRY(thr);

	if (DUK_UNLIKELY(top < 0 || top > DUK_USE_VALSTACK_LIMIT)) {
		if (top < 0) {
			/* Clamping to zero makes the API more robust to calling code
			 * calculation errors.
			 */
			top = 0;
		} else {
			/* Cause grow check to fail without wrapping arithmetic. */
			top = DUK_USE_VALSTACK_LIMIT;
		}
	}

	DUK_ASSERT(top >= 0);
	min_new_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) +
	                sizeof(duk_tval) * ((duk_size_t) top + DUK_VALSTACK_INTERNAL_EXTRA);
	duk_valstack_grow_check_throw(thr, min_new_bytes);
}

/*
 *  Basic stack manipulation: swap, dup, insert, replace, etc
 */

DUK_EXTERNAL void duk_swap(duk_hthread *thr, duk_idx_t idx1, duk_idx_t idx2) {
	duk_tval *tv1;
	duk_tval *tv2;
	duk_tval tv_tmp;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_require_tval(thr, idx1);
	DUK_ASSERT(tv1 != NULL);
	tv2 = duk_require_tval(thr, idx2);
	DUK_ASSERT(tv2 != NULL);

	/* If tv1==tv2 this is a NOP, no check is needed */
	DUK_TVAL_SET_TVAL(&tv_tmp, tv1);
	DUK_TVAL_SET_TVAL(tv1, tv2);
	DUK_TVAL_SET_TVAL(tv2, &tv_tmp);
}

DUK_EXTERNAL void duk_swap_top(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_swap(thr, idx, -1);
}

DUK_EXTERNAL void duk_dup(duk_hthread *thr, duk_idx_t from_idx) {
	duk_tval *tv_from;
	duk_tval *tv_to;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();

	tv_from = duk_require_tval(thr, from_idx);
	tv_to = thr->valstack_top++;
	DUK_ASSERT(tv_from != NULL);
	DUK_ASSERT(tv_to != NULL);
	DUK_TVAL_SET_TVAL(tv_to, tv_from);
	DUK_TVAL_INCREF(thr, tv_to);  /* no side effects */
}

DUK_EXTERNAL void duk_dup_top(duk_hthread *thr) {
#if defined(DUK_USE_PREFER_SIZE)
	duk_dup(thr, -1);
#else
	duk_tval *tv_from;
	duk_tval *tv_to;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();

	if (DUK_UNLIKELY(thr->valstack_top - thr->valstack_bottom <= 0)) {
		DUK_ERROR_RANGE_INDEX(thr, -1);
		DUK_WO_NORETURN(return;);
	}
	tv_from = thr->valstack_top - 1;
	tv_to = thr->valstack_top++;
	DUK_ASSERT(tv_from != NULL);
	DUK_ASSERT(tv_to != NULL);
	DUK_TVAL_SET_TVAL(tv_to, tv_from);
	DUK_TVAL_INCREF(thr, tv_to);  /* no side effects */
#endif
}

DUK_INTERNAL void duk_dup_0(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, 0);
}
DUK_INTERNAL void duk_dup_1(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, 1);
}
DUK_INTERNAL void duk_dup_2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, 2);
}
DUK_INTERNAL void duk_dup_m2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, -2);
}
DUK_INTERNAL void duk_dup_m3(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, -3);
}
DUK_INTERNAL void duk_dup_m4(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_dup(thr, -4);
}

DUK_EXTERNAL void duk_insert(duk_hthread *thr, duk_idx_t to_idx) {
	duk_tval *p;
	duk_tval *q;
	duk_tval tv_tmp;
	duk_size_t nbytes;

	DUK_ASSERT_API_ENTRY(thr);

	p = duk_require_tval(thr, to_idx);
	DUK_ASSERT(p != NULL);
	q = duk_require_tval(thr, -1);
	DUK_ASSERT(q != NULL);

	DUK_ASSERT(q >= p);

	/*              nbytes
	 *           <--------->
	 *    [ ... | p | x | x | q ]
	 * => [ ... | q | p | x | x ]
	 */

	nbytes = (duk_size_t) (((duk_uint8_t *) q) - ((duk_uint8_t *) p));

	DUK_DDD(DUK_DDDPRINT("duk_insert: to_idx=%ld, p=%p, q=%p, nbytes=%lu",
	                     (long) to_idx, (void *) p, (void *) q, (unsigned long) nbytes));

	/* No net refcount changes.  No need to special case nbytes == 0
	 * (p == q).
	 */
	DUK_TVAL_SET_TVAL(&tv_tmp, q);
	duk_memmove((void *) (p + 1), (const void *) p, (size_t) nbytes);
	DUK_TVAL_SET_TVAL(p, &tv_tmp);
}

DUK_INTERNAL void duk_insert_undefined(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(idx >= 0);  /* Doesn't support negative indices. */

	duk_push_undefined(thr);
	duk_insert(thr, idx);
}

DUK_INTERNAL void duk_insert_undefined_n(duk_hthread *thr, duk_idx_t idx, duk_idx_t count) {
	duk_tval *tv, *tv_end;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(idx >= 0);  /* Doesn't support negative indices or count. */
	DUK_ASSERT(count >= 0);

	tv = duk_reserve_gap(thr, idx, count);
	tv_end = tv + count;
	while (tv != tv_end) {
		DUK_TVAL_SET_UNDEFINED(tv);
		tv++;
	}
}

DUK_EXTERNAL void duk_pull(duk_hthread *thr, duk_idx_t from_idx) {
	duk_tval *p;
	duk_tval *q;
	duk_tval tv_tmp;
	duk_size_t nbytes;

	DUK_ASSERT_API_ENTRY(thr);

	/*                         nbytes
	 *                       <--------->
	 *    [ ... | x | x | p | y | y | q ]
	 * => [ ... | x | x | y | y | q | p ]
	 */

	p = duk_require_tval(thr, from_idx);
	DUK_ASSERT(p != NULL);
	q = duk_require_tval(thr, -1);
	DUK_ASSERT(q != NULL);

	DUK_ASSERT(q >= p);

	nbytes = (duk_size_t) (((duk_uint8_t *) q) - ((duk_uint8_t *) p));

	DUK_DDD(DUK_DDDPRINT("duk_pull: from_idx=%ld, p=%p, q=%p, nbytes=%lu",
	                     (long) from_idx, (void *) p, (void *) q, (unsigned long) nbytes));

	/* No net refcount changes.  No need to special case nbytes == 0
	 * (p == q).
	 */
	DUK_TVAL_SET_TVAL(&tv_tmp, p);
	duk_memmove((void *) p, (const void *) (p + 1), (size_t) nbytes);
	DUK_TVAL_SET_TVAL(q, &tv_tmp);
}

DUK_EXTERNAL void duk_replace(duk_hthread *thr, duk_idx_t to_idx) {
	duk_tval *tv1;
	duk_tval *tv2;
	duk_tval tv_tmp;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_require_tval(thr, -1);
	DUK_ASSERT(tv1 != NULL);
	tv2 = duk_require_tval(thr, to_idx);
	DUK_ASSERT(tv2 != NULL);

	/* For tv1 == tv2, both pointing to stack top, the end result
	 * is same as duk_pop(thr).
	 */
	DUK_TVAL_SET_TVAL(&tv_tmp, tv2);
	DUK_TVAL_SET_TVAL(tv2, tv1);
	DUK_TVAL_SET_UNDEFINED(tv1);
	thr->valstack_top--;
	DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */
}

DUK_EXTERNAL void duk_copy(duk_hthread *thr, duk_idx_t from_idx, duk_idx_t to_idx) {
	duk_tval *tv1;
	duk_tval *tv2;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_require_tval(thr, from_idx);
	DUK_ASSERT(tv1 != NULL);
	tv2 = duk_require_tval(thr, to_idx);
	DUK_ASSERT(tv2 != NULL);

	/* For tv1 == tv2, this is a no-op (no explicit check needed). */
	DUK_TVAL_SET_TVAL_UPDREF(thr, tv2, tv1);  /* side effects */
}

DUK_EXTERNAL void duk_remove(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *p;
	duk_tval *q;
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_tval tv_tmp;
#endif
	duk_size_t nbytes;

	DUK_ASSERT_API_ENTRY(thr);

	p = duk_require_tval(thr, idx);
	DUK_ASSERT(p != NULL);
	q = duk_require_tval(thr, -1);
	DUK_ASSERT(q != NULL);

	DUK_ASSERT(q >= p);

	/*              nbytes            zero size case
	 *           <--------->
	 *    [ ... | p | x | x | q ]     [ ... | p==q ]
	 * => [ ... | x | x | q ]         [ ... ]
	 */

#if defined(DUK_USE_REFERENCE_COUNTING)
	/* use a temp: decref only when valstack reachable values are correct */
	DUK_TVAL_SET_TVAL(&tv_tmp, p);
#endif

	nbytes = (duk_size_t) (((duk_uint8_t *) q) - ((duk_uint8_t *) p));  /* Note: 'q' is top-1 */
	duk_memmove((void *) p, (const void *) (p + 1), (size_t) nbytes);

	DUK_TVAL_SET_UNDEFINED(q);
	thr->valstack_top--;

#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */
#endif
}

DUK_INTERNAL void duk_remove_unsafe(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_remove(thr, idx);  /* XXX: no optimization for now */
}

DUK_INTERNAL void duk_remove_m2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_remove(thr, -2);
}

DUK_INTERNAL void duk_remove_n(duk_hthread *thr, duk_idx_t idx, duk_idx_t count) {
#if defined(DUK_USE_PREFER_SIZE)
	/* XXX: maybe too slow even when preferring size? */
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(count >= 0);
	DUK_ASSERT(idx >= 0);

	while (count-- > 0) {
		duk_remove(thr, idx);
	}
#else  /* DUK_USE_PREFER_SIZE */
	duk_tval *tv_src;
	duk_tval *tv_dst;
	duk_tval *tv_newtop;
	duk_tval *tv;
	duk_size_t bytes;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(count >= 0);
	DUK_ASSERT(idx >= 0);

	tv_dst = thr->valstack_bottom + idx;
	DUK_ASSERT(tv_dst <= thr->valstack_top);
	tv_src = tv_dst + count;
	DUK_ASSERT(tv_src <= thr->valstack_top);
	bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) tv_src);

	for (tv = tv_dst; tv < tv_src; tv++) {
		DUK_TVAL_DECREF_NORZ(thr, tv);
	}

	duk_memmove((void *) tv_dst, (const void *) tv_src, bytes);

	tv_newtop = thr->valstack_top - count;
	for (tv = tv_newtop; tv < thr->valstack_top; tv++) {
		DUK_TVAL_SET_UNDEFINED(tv);
	}
	thr->valstack_top = tv_newtop;

	/* When not preferring size, only NORZ macros are used; caller
	 * is expected to DUK_REFZERO_CHECK().
	 */
#endif  /* DUK_USE_PREFER_SIZE */
}

DUK_INTERNAL void duk_remove_n_unsafe(duk_hthread *thr, duk_idx_t idx, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_remove_n(thr, idx, count);  /* XXX: no optimization for now */
}

/*
 *  Stack slice primitives
 */

DUK_EXTERNAL void duk_xcopymove_raw(duk_hthread *to_thr, duk_hthread *from_thr, duk_idx_t count, duk_bool_t is_copy) {
	void *src;
	duk_size_t nbytes;
	duk_tval *p;
	duk_tval *q;

	/* XXX: several pointer comparison issues here */

	DUK_ASSERT_API_ENTRY(to_thr);
	DUK_CTX_ASSERT_VALID(to_thr);
	DUK_CTX_ASSERT_VALID(from_thr);
	DUK_ASSERT(to_thr->heap == from_thr->heap);

	if (DUK_UNLIKELY(to_thr == from_thr)) {
		DUK_ERROR_TYPE(to_thr, DUK_STR_INVALID_CONTEXT);
		DUK_WO_NORETURN(return;);
	}
	if (DUK_UNLIKELY((duk_uidx_t) count > (duk_uidx_t) DUK_USE_VALSTACK_LIMIT)) {
		/* Maximum value check ensures 'nbytes' won't wrap below.
		 * Also handles negative count.
		 */
		DUK_ERROR_RANGE_INVALID_COUNT(to_thr);
		DUK_WO_NORETURN(return;);
	}
	DUK_ASSERT(count >= 0);

	nbytes = sizeof(duk_tval) * (duk_size_t) count;
	if (DUK_UNLIKELY(nbytes == 0)) {
		return;
	}
	DUK_ASSERT(to_thr->valstack_top <= to_thr->valstack_end);
	if (DUK_UNLIKELY((duk_size_t) ((duk_uint8_t *) to_thr->valstack_end - (duk_uint8_t *) to_thr->valstack_top) < nbytes)) {
		DUK_ERROR_RANGE_PUSH_BEYOND(to_thr);
		DUK_WO_NORETURN(return;);
	}
	src = (void *) ((duk_uint8_t *) from_thr->valstack_top - nbytes);
	if (DUK_UNLIKELY(src < (void *) from_thr->valstack_bottom)) {
		DUK_ERROR_RANGE_INVALID_COUNT(to_thr);
		DUK_WO_NORETURN(return;);
	}

	/* Copy values (no overlap even if to_thr == from_thr; that's not
	 * allowed now anyway).
	 */
	DUK_ASSERT(nbytes > 0);
	duk_memcpy((void *) to_thr->valstack_top, (const void *) src, (size_t) nbytes);

	p = to_thr->valstack_top;
	to_thr->valstack_top = (duk_tval *) (void *) (((duk_uint8_t *) p) + nbytes);

	if (is_copy) {
		/* Incref copies, keep originals. */
		q = to_thr->valstack_top;
		while (p < q) {
			DUK_TVAL_INCREF(to_thr, p);  /* no side effects */
			p++;
		}
	} else {
		/* No net refcount change. */
		p = from_thr->valstack_top;
		q = (duk_tval *) (void *) (((duk_uint8_t *) p) - nbytes);
		from_thr->valstack_top = q;

		while (p > q) {
			p--;
			DUK_TVAL_SET_UNDEFINED(p);
			/* XXX: fast primitive to set a bunch of values to UNDEFINED */
		}
	}
}

/* Internal helper: reserve a gap of 'count' elements at 'idx_base' and return a
 * pointer to the gap.  Values in the gap are garbage and MUST be initialized by
 * the caller before any side effects may occur.  The caller must ensure there's
 * enough stack reserve for 'count' values.
 */
DUK_INTERNAL duk_tval *duk_reserve_gap(duk_hthread *thr, duk_idx_t idx_base, duk_idx_t count) {
	duk_tval *tv_src;
	duk_tval *tv_dst;
	duk_size_t gap_bytes;
	duk_size_t copy_bytes;

	/* Caller is responsible for ensuring there's enough preallocated
	 * value stack.
	 */
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(count >= 0);
	DUK_ASSERT((duk_size_t) (thr->valstack_end - thr->valstack_top) >= (duk_size_t) count);

	tv_src = thr->valstack_bottom + idx_base;
	gap_bytes = (duk_size_t) count * sizeof(duk_tval);
	tv_dst = (duk_tval *) (void *) ((duk_uint8_t *) tv_src + gap_bytes);
	copy_bytes = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) tv_src);
	thr->valstack_top = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_top + gap_bytes);
	duk_memmove((void *) tv_dst, (const void *) tv_src, copy_bytes);

	/* Values in the gap are left as garbage: caller must fill them in
	 * and INCREF them before any side effects.
	 */
	return tv_src;
}

/*
 *  Get/opt/require
 */

DUK_EXTERNAL void duk_require_undefined(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_UNDEFINED(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "undefined", DUK_STR_NOT_UNDEFINED);
		DUK_WO_NORETURN(return;);
	}
}

DUK_EXTERNAL void duk_require_null(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_NULL(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "null", DUK_STR_NOT_NULL);
		DUK_WO_NORETURN(return;);
	}
}

DUK_LOCAL DUK_ALWAYS_INLINE duk_bool_t duk__get_boolean_raw(duk_hthread *thr, duk_idx_t idx, duk_bool_t def_value) {
	duk_bool_t ret;
	duk_tval *tv;

	DUK_CTX_ASSERT_VALID(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_BOOLEAN(tv)) {
		ret = DUK_TVAL_GET_BOOLEAN(tv);
		DUK_ASSERT(ret == 0 || ret == 1);
	} else {
		ret = def_value;
		/* Not guaranteed to be 0 or 1. */
	}

	return ret;
}

DUK_EXTERNAL duk_bool_t duk_get_boolean(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk__get_boolean_raw(thr, idx, 0);  /* default: false */
}

DUK_EXTERNAL duk_bool_t duk_get_boolean_default(duk_hthread *thr, duk_idx_t idx, duk_bool_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk__get_boolean_raw(thr, idx, def_value);
}

DUK_EXTERNAL duk_bool_t duk_require_boolean(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_bool_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_LIKELY(DUK_TVAL_IS_BOOLEAN(tv))) {
		ret = DUK_TVAL_GET_BOOLEAN(tv);
		DUK_ASSERT(ret == 0 || ret == 1);
		return ret;
	} else {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "boolean", DUK_STR_NOT_BOOLEAN);
		DUK_WO_NORETURN(return 0;);
	}
}

DUK_EXTERNAL duk_bool_t duk_opt_boolean(duk_hthread *thr, duk_idx_t idx, duk_bool_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_boolean(thr, idx);
}

DUK_LOCAL DUK_ALWAYS_INLINE duk_double_t duk__get_number_raw(duk_hthread *thr, duk_idx_t idx, duk_double_t def_value) {
	duk_double_union ret;
	duk_tval *tv;

	DUK_CTX_ASSERT_VALID(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		ret.d = (duk_double_t) DUK_TVAL_GET_FASTINT(tv);  /* XXX: cast trick */
	}
	else
#endif
	if (DUK_TVAL_IS_DOUBLE(tv)) {
		/* When using packed duk_tval, number must be in NaN-normalized form
		 * for it to be a duk_tval, so no need to normalize.  NOP for unpacked
		 * duk_tval.
		 */
		ret.d = DUK_TVAL_GET_DOUBLE(tv);
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&ret));
	} else {
		ret.d = def_value;
		/* Default value (including NaN) may not be normalized. */
	}

	return ret.d;
}

DUK_EXTERNAL duk_double_t duk_get_number(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_number_raw(thr, idx, DUK_DOUBLE_NAN);  /* default: NaN */
}

DUK_EXTERNAL duk_double_t duk_get_number_default(duk_hthread *thr, duk_idx_t idx, duk_double_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_number_raw(thr, idx, def_value);
}

DUK_EXTERNAL duk_double_t duk_require_number(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_double_union ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_NUMBER(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "number", DUK_STR_NOT_NUMBER);
		DUK_WO_NORETURN(return 0.0;);
	}

	ret.d = DUK_TVAL_GET_NUMBER(tv);

	/* When using packed duk_tval, number must be in NaN-normalized form
	 * for it to be a duk_tval, so no need to normalize.  NOP for unpacked
	 * duk_tval.
	 */
	DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&ret));
	return ret.d;
}

DUK_EXTERNAL duk_double_t duk_opt_number(duk_hthread *thr, duk_idx_t idx, duk_double_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		/* User provided default is not NaN normalized. */
		return def_value;
	}
	return duk_require_number(thr, idx);
}

DUK_EXTERNAL duk_int_t duk_get_int(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_int_t) duk__api_coerce_d2i(thr, idx, 0 /*def_value*/, 0 /*require*/);
}

DUK_EXTERNAL duk_uint_t duk_get_uint(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_uint_t) duk__api_coerce_d2ui(thr, idx, 0 /*def_value*/, 0 /*require*/);
}

DUK_EXTERNAL duk_int_t duk_get_int_default(duk_hthread *thr, duk_idx_t idx, duk_int_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_int_t) duk__api_coerce_d2i(thr, idx, def_value, 0 /*require*/);
}

DUK_EXTERNAL duk_uint_t duk_get_uint_default(duk_hthread *thr, duk_idx_t idx, duk_uint_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_uint_t) duk__api_coerce_d2ui(thr, idx, def_value, 0 /*require*/);
}

DUK_EXTERNAL duk_int_t duk_require_int(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_int_t) duk__api_coerce_d2i(thr, idx, 0 /*def_value*/, 1 /*require*/);
}

DUK_EXTERNAL duk_uint_t duk_require_uint(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_uint_t) duk__api_coerce_d2ui(thr, idx, 0 /*def_value*/, 1 /*require*/);
}

DUK_EXTERNAL duk_int_t duk_opt_int(duk_hthread *thr, duk_idx_t idx, duk_int_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_int(thr, idx);
}

DUK_EXTERNAL duk_uint_t duk_opt_uint(duk_hthread *thr, duk_idx_t idx, duk_uint_t def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_uint(thr, idx);
}

DUK_EXTERNAL const char *duk_get_lstring(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	duk_hstring *h;
	const char *ret;
	duk_size_t len;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hstring(thr, idx);
	if (h != NULL) {
		len = DUK_HSTRING_GET_BYTELEN(h);
		ret = (const char *) DUK_HSTRING_GET_DATA(h);
	} else {
		len = 0;
		ret = NULL;
	}

	if (out_len != NULL) {
		*out_len = len;
	}
	return ret;
}

DUK_EXTERNAL const char *duk_require_lstring(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_require_hstring(thr, idx);
	DUK_ASSERT(h != NULL);
	if (out_len) {
		*out_len = DUK_HSTRING_GET_BYTELEN(h);
	}
	return (const char *) DUK_HSTRING_GET_DATA(h);
}

DUK_INTERNAL const char *duk_require_lstring_notsymbol(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_require_hstring_notsymbol(thr, idx);
	DUK_ASSERT(h != NULL);
	if (out_len) {
		*out_len = DUK_HSTRING_GET_BYTELEN(h);
	}
	return (const char *) DUK_HSTRING_GET_DATA(h);
}

DUK_EXTERNAL const char *duk_get_string(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hstring(thr, idx);
	if (h != NULL) {
		return (const char *) DUK_HSTRING_GET_DATA(h);
	} else {
		return NULL;
	}
}

DUK_EXTERNAL const char *duk_opt_lstring(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len, const char *def_ptr, duk_size_t def_len) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		if (out_len != NULL) {
			*out_len = def_len;
		}
		return def_ptr;
	}
	return duk_require_lstring(thr, idx, out_len);
}

DUK_EXTERNAL const char *duk_opt_string(duk_hthread *thr, duk_idx_t idx, const char *def_ptr) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_ptr;
	}
	return duk_require_string(thr, idx);
}

DUK_EXTERNAL const char *duk_get_lstring_default(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len, const char *def_ptr, duk_size_t def_len) {
	duk_hstring *h;
	const char *ret;
	duk_size_t len;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hstring(thr, idx);
	if (h != NULL) {
		len = DUK_HSTRING_GET_BYTELEN(h);
		ret = (const char *) DUK_HSTRING_GET_DATA(h);
	} else {
		len = def_len;
		ret = def_ptr;
	}

	if (out_len != NULL) {
		*out_len = len;
	}
	return ret;
}

DUK_EXTERNAL const char *duk_get_string_default(duk_hthread *thr, duk_idx_t idx, const char *def_value) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hstring(thr, idx);
	if (h != NULL) {
		return (const char *) DUK_HSTRING_GET_DATA(h);
	} else {
		return def_value;
	}
}

DUK_INTERNAL const char *duk_get_string_notsymbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hstring_notsymbol(thr, idx);
	if (h) {
		return (const char *) DUK_HSTRING_GET_DATA(h);
	} else {
		return NULL;
	}
}

DUK_EXTERNAL const char *duk_require_string(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk_require_lstring(thr, idx, NULL);
}

DUK_INTERNAL const char *duk_require_string_notsymbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_require_hstring_notsymbol(thr, idx);
	DUK_ASSERT(h != NULL);
	return (const char *) DUK_HSTRING_GET_DATA(h);
}

DUK_EXTERNAL void duk_require_object(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_OBJECT(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "object", DUK_STR_NOT_OBJECT);
		DUK_WO_NORETURN(return;);
	}
}

DUK_LOCAL void *duk__get_pointer_raw(duk_hthread *thr, duk_idx_t idx, void *def_value) {
	duk_tval *tv;
	void *p;

	DUK_CTX_ASSERT_VALID(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (!DUK_TVAL_IS_POINTER(tv)) {
		return def_value;
	}

	p = DUK_TVAL_GET_POINTER(tv);  /* may be NULL */
	return p;
}

DUK_EXTERNAL void *duk_get_pointer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_pointer_raw(thr, idx, NULL /*def_value*/);
}

DUK_EXTERNAL void *duk_opt_pointer(duk_hthread *thr, duk_idx_t idx, void *def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_pointer(thr, idx);
}

DUK_EXTERNAL void *duk_get_pointer_default(duk_hthread *thr, duk_idx_t idx, void *def_value) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_pointer_raw(thr, idx, def_value);
}

DUK_EXTERNAL void *duk_require_pointer(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	void *p;

	DUK_ASSERT_API_ENTRY(thr);

	/* Note: here we must be wary of the fact that a pointer may be
	 * valid and be a NULL.
	 */
	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_POINTER(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "pointer", DUK_STR_NOT_POINTER);
		DUK_WO_NORETURN(return NULL;);
	}
	p = DUK_TVAL_GET_POINTER(tv);  /* may be NULL */
	return p;
}

#if 0  /*unused*/
DUK_INTERNAL void *duk_get_voidptr(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_heaphdr *h;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (!DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		return NULL;
	}

	h = DUK_TVAL_GET_HEAPHDR(tv);
	DUK_ASSERT(h != NULL);
	return (void *) h;
}
#endif

DUK_LOCAL void *duk__get_buffer_helper(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_size, duk_bool_t throw_flag) {
	duk_hbuffer *h;
	void *ret;
	duk_size_t len;
	duk_tval *tv;

	DUK_CTX_ASSERT_VALID(thr);

	if (out_size != NULL) {
		*out_size = 0;
	}

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_LIKELY(DUK_TVAL_IS_BUFFER(tv))) {
		h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);

		len = DUK_HBUFFER_GET_SIZE(h);
		ret = DUK_HBUFFER_GET_DATA_PTR(thr->heap, h);
	} else {
		if (throw_flag) {
			DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "buffer", DUK_STR_NOT_BUFFER);
			DUK_WO_NORETURN(return NULL;);
		}
		len = def_size;
		ret = def_ptr;
	}

	if (out_size != NULL) {
		*out_size = len;
	}
	return ret;
}

DUK_EXTERNAL void *duk_get_buffer(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk__get_buffer_helper(thr, idx, out_size, NULL /*def_ptr*/, 0 /*def_size*/, 0 /*throw_flag*/);
}

DUK_EXTERNAL void *duk_opt_buffer(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_size) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		if (out_size != NULL) {
			*out_size = def_size;
		}
		return def_ptr;
	}
	return duk_require_buffer(thr, idx, out_size);
}

DUK_EXTERNAL void *duk_get_buffer_default(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_len) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk__get_buffer_helper(thr, idx, out_size, def_ptr, def_len, 0 /*throw_flag*/);
}

DUK_EXTERNAL void *duk_require_buffer(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk__get_buffer_helper(thr, idx, out_size, NULL /*def_ptr*/, 0 /*def_size*/, 1 /*throw_flag*/);
}

/* Get the active buffer data area for a plain buffer or a buffer object.
 * Return NULL if the the value is not a buffer.  Note that a buffer may
 * have a NULL data pointer when its size is zero, the optional 'out_isbuffer'
 * argument allows caller to detect this reliably.
 */
DUK_INTERNAL void *duk_get_buffer_data_raw(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_size, duk_bool_t throw_flag, duk_bool_t *out_isbuffer) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	if (out_isbuffer != NULL) {
		*out_isbuffer = 0;
	}
	if (out_size != NULL) {
		*out_size = def_size;
	}

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		if (out_size != NULL) {
			*out_size = DUK_HBUFFER_GET_SIZE(h);
		}
		if (out_isbuffer != NULL) {
			*out_isbuffer = 1;
		}
		return (void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h);  /* may be NULL (but only if size is 0) */
	}
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	else if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			/* XXX: this is probably a useful shared helper: for a
			 * duk_hbufobj, get a validated buffer pointer/length.
			 */
			duk_hbufobj *h_bufobj = (duk_hbufobj *) h;
			DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

			if (h_bufobj->buf != NULL &&
			    DUK_HBUFOBJ_VALID_SLICE(h_bufobj)) {
				duk_uint8_t *p;

				p = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufobj->buf);
				if (out_size != NULL) {
					*out_size = (duk_size_t) h_bufobj->length;
				}
				if (out_isbuffer != NULL) {
					*out_isbuffer = 1;
				}
				return (void *) (p + h_bufobj->offset);
			}
			/* if slice not fully valid, treat as error */
		}
	}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

	if (throw_flag) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "buffer", DUK_STR_NOT_BUFFER);
		DUK_WO_NORETURN(return NULL;);
	}
	return def_ptr;
}

DUK_EXTERNAL void *duk_get_buffer_data(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_get_buffer_data_raw(thr, idx, out_size, NULL /*def_ptr*/, 0 /*def_size*/, 0 /*throw_flag*/, NULL);
}

DUK_EXTERNAL void *duk_get_buffer_data_default(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_size) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_get_buffer_data_raw(thr, idx, out_size, def_ptr, def_size, 0 /*throw_flag*/, NULL);
}

DUK_EXTERNAL void *duk_opt_buffer_data(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, void *def_ptr, duk_size_t def_size) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		if (out_size != NULL) {
			*out_size = def_size;
		}
		return def_ptr;
	}
	return duk_require_buffer_data(thr, idx, out_size);
}

DUK_EXTERNAL void *duk_require_buffer_data(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_get_buffer_data_raw(thr, idx, out_size, NULL /*def_ptr*/, 0 /*def_size*/, 1 /*throw_flag*/, NULL);
}

/* Raw helper for getting a value from the stack, checking its tag.
 * The tag cannot be a number because numbers don't have an internal
 * tag in the packed representation.
 */

DUK_LOCAL duk_heaphdr *duk__get_tagged_heaphdr_raw(duk_hthread *thr, duk_idx_t idx, duk_uint_t tag) {
	duk_tval *tv;
	duk_heaphdr *ret;

	DUK_CTX_ASSERT_VALID(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_GET_TAG(tv) != tag) {
		return (duk_heaphdr *) NULL;
	}

	ret = DUK_TVAL_GET_HEAPHDR(tv);
	DUK_ASSERT(ret != NULL);  /* tagged null pointers should never occur */
	return ret;

}

DUK_INTERNAL duk_hstring *duk_get_hstring(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return (duk_hstring *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_STRING);
}

DUK_INTERNAL duk_hstring *duk_get_hstring_notsymbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hstring *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_STRING);
	if (DUK_UNLIKELY(h && DUK_HSTRING_HAS_SYMBOL(h))) {
		return NULL;
	}
	return h;
}

DUK_INTERNAL duk_hstring *duk_require_hstring(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hstring *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_STRING);
	if (DUK_UNLIKELY(h == NULL)) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "string", DUK_STR_NOT_STRING);
		DUK_WO_NORETURN(return NULL;);
	}
	return h;
}

DUK_INTERNAL duk_hstring *duk_require_hstring_notsymbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hstring *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_STRING);
	if (DUK_UNLIKELY(h == NULL || DUK_HSTRING_HAS_SYMBOL(h))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "string", DUK_STR_NOT_STRING);
		DUK_WO_NORETURN(return NULL;);
	}
	return h;
}

DUK_INTERNAL duk_hobject *duk_get_hobject(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
}

DUK_INTERNAL duk_hobject *duk_require_hobject(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(h == NULL)) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "object", DUK_STR_NOT_OBJECT);
		DUK_WO_NORETURN(return NULL;);
	}
	return h;
}

DUK_INTERNAL duk_hbuffer *duk_get_hbuffer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return (duk_hbuffer *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_BUFFER);
}

DUK_INTERNAL duk_hbuffer *duk_require_hbuffer(duk_hthread *thr, duk_idx_t idx) {
	duk_hbuffer *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hbuffer *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_BUFFER);
	if (DUK_UNLIKELY(h == NULL)) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "buffer", DUK_STR_NOT_BUFFER);
		DUK_WO_NORETURN(return NULL;);
	}
	return h;
}

DUK_INTERNAL duk_hthread *duk_get_hthread(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(h != NULL && !DUK_HOBJECT_IS_THREAD(h))) {
		h = NULL;
	}
	return (duk_hthread *) h;
}

DUK_INTERNAL duk_hthread *duk_require_hthread(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(!(h != NULL && DUK_HOBJECT_IS_THREAD(h)))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "thread", DUK_STR_NOT_THREAD);
		DUK_WO_NORETURN(return NULL;);
	}
	return (duk_hthread *) h;
}

DUK_INTERNAL duk_hcompfunc *duk_get_hcompfunc(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(h != NULL && !DUK_HOBJECT_IS_COMPFUNC(h))) {
		h = NULL;
	}
	return (duk_hcompfunc *) h;
}

DUK_INTERNAL duk_hcompfunc *duk_require_hcompfunc(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(!(h != NULL && DUK_HOBJECT_IS_COMPFUNC(h)))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "compiledfunction", DUK_STR_NOT_COMPFUNC);
		DUK_WO_NORETURN(return NULL;);
	}
	return (duk_hcompfunc *) h;
}

DUK_INTERNAL duk_hnatfunc *duk_get_hnatfunc(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(h != NULL && !DUK_HOBJECT_IS_NATFUNC(h))) {
		h = NULL;
	}
	return (duk_hnatfunc *) h;
}

DUK_INTERNAL duk_hnatfunc *duk_require_hnatfunc(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(!(h != NULL && DUK_HOBJECT_IS_NATFUNC(h)))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "nativefunction", DUK_STR_NOT_NATFUNC);
		DUK_WO_NORETURN(return NULL;);
	}
	return (duk_hnatfunc *) h;
}

DUK_EXTERNAL duk_c_function duk_get_c_function(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_hobject *h;
	duk_hnatfunc *f;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_OBJECT(tv))) {
		return NULL;
	}
	h = DUK_TVAL_GET_OBJECT(tv);
	DUK_ASSERT(h != NULL);

	if (DUK_UNLIKELY(!DUK_HOBJECT_IS_NATFUNC(h))) {
		return NULL;
	}
	DUK_ASSERT(DUK_HOBJECT_HAS_NATFUNC(h));
	f = (duk_hnatfunc *) h;

	return f->func;
}

DUK_EXTERNAL duk_c_function duk_opt_c_function(duk_hthread *thr, duk_idx_t idx, duk_c_function def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_c_function(thr, idx);
}

DUK_EXTERNAL duk_c_function duk_get_c_function_default(duk_hthread *thr, duk_idx_t idx, duk_c_function def_value) {
	duk_c_function ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = duk_get_c_function(thr, idx);
	if (ret != NULL) {
		return ret;
	}

	return def_value;
}

DUK_EXTERNAL duk_c_function duk_require_c_function(duk_hthread *thr, duk_idx_t idx) {
	duk_c_function ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = duk_get_c_function(thr, idx);
	if (DUK_UNLIKELY(!ret)) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "nativefunction", DUK_STR_NOT_NATFUNC);
		DUK_WO_NORETURN(return ret;);
	}
	return ret;
}

DUK_EXTERNAL void duk_require_function(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	if (DUK_UNLIKELY(!duk_is_function(thr, idx))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "function", DUK_STR_NOT_FUNCTION);
		DUK_WO_NORETURN(return;);
	}
}

DUK_EXTERNAL void duk_require_constructable(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_require_hobject_accept_mask(thr, idx, DUK_TYPE_MASK_LIGHTFUNC);
	if (DUK_UNLIKELY(h != NULL && !DUK_HOBJECT_HAS_CONSTRUCTABLE(h))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "constructable", DUK_STR_NOT_CONSTRUCTABLE);
		DUK_WO_NORETURN(return;);
	}
	/* Lightfuncs (h == NULL) are constructable. */
}

DUK_EXTERNAL duk_hthread *duk_get_context(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk_get_hthread(thr, idx);
}

DUK_EXTERNAL duk_hthread *duk_require_context(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk_require_hthread(thr, idx);
}

DUK_EXTERNAL duk_hthread *duk_opt_context(duk_hthread *thr, duk_idx_t idx, duk_hthread *def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_context(thr, idx);
}

DUK_EXTERNAL duk_hthread *duk_get_context_default(duk_hthread *thr, duk_idx_t idx, duk_hthread *def_value) {
	duk_hthread *ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = duk_get_context(thr, idx);
	if (ret != NULL) {
		return ret;
	}

	return def_value;
}

DUK_EXTERNAL void *duk_get_heapptr(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	void *ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_HEAP_ALLOCATED(tv))) {
		return (void *) NULL;
	}

	ret = (void *) DUK_TVAL_GET_HEAPHDR(tv);
	DUK_ASSERT(ret != NULL);
	return ret;
}

DUK_EXTERNAL void *duk_opt_heapptr(duk_hthread *thr, duk_idx_t idx, void *def_value) {
	DUK_ASSERT_API_ENTRY(thr);

	if (duk_check_type_mask(thr, idx, DUK_TYPE_MASK_NONE | DUK_TYPE_MASK_UNDEFINED)) {
		return def_value;
	}
	return duk_require_heapptr(thr, idx);
}

DUK_EXTERNAL void *duk_get_heapptr_default(duk_hthread *thr, duk_idx_t idx, void *def_value) {
	void *ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = duk_get_heapptr(thr, idx);
	if (ret != NULL) {
		return ret;
	}

	return def_value;
}

DUK_EXTERNAL void *duk_require_heapptr(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	void *ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_UNLIKELY(!DUK_TVAL_IS_HEAP_ALLOCATED(tv))) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "heapobject", DUK_STR_UNEXPECTED_TYPE);
		DUK_WO_NORETURN(return NULL;);
	}

	ret = (void *) DUK_TVAL_GET_HEAPHDR(tv);
	DUK_ASSERT(ret != NULL);
	return ret;
}

/* Internal helper for getting/requiring a duk_hobject with possible promotion. */
DUK_LOCAL duk_hobject *duk__get_hobject_promote_mask_raw(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask) {
	duk_uint_t val_mask;
	duk_hobject *res;

	DUK_CTX_ASSERT_VALID(thr);

	res = duk_get_hobject(thr, idx);  /* common case, not promoted */
	if (DUK_LIKELY(res != NULL)) {
		DUK_ASSERT(res != NULL);
		return res;
	}

	val_mask = duk_get_type_mask(thr, idx);
	if (val_mask & type_mask) {
		if (type_mask & DUK_TYPE_MASK_PROMOTE) {
			res = duk_to_hobject(thr, idx);
			DUK_ASSERT(res != NULL);
			return res;
		} else {
			return NULL;  /* accept without promoting */
		}
	}

	if (type_mask & DUK_TYPE_MASK_THROW) {
		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, "object", DUK_STR_NOT_OBJECT);
		DUK_WO_NORETURN(return NULL;);
	}
	return NULL;
}

/* Get a duk_hobject * at 'idx'; if the value is not an object but matches the
 * supplied 'type_mask', promote it to an object and return the duk_hobject *.
 * This is useful for call sites which want an object but also accept a plain
 * buffer and/or a lightfunc which gets automatically promoted to an object.
 * Return value is NULL if value is neither an object nor a plain type allowed
 * by the mask.
 */
DUK_INTERNAL duk_hobject *duk_get_hobject_promote_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_hobject_promote_mask_raw(thr, idx, type_mask | DUK_TYPE_MASK_PROMOTE);
}

/* Like duk_get_hobject_promote_mask() but throw a TypeError instead of
 * returning a NULL.
 */
DUK_INTERNAL duk_hobject *duk_require_hobject_promote_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_hobject_promote_mask_raw(thr, idx, type_mask | DUK_TYPE_MASK_THROW | DUK_TYPE_MASK_PROMOTE);
}

/* Require a duk_hobject * at 'idx'; if the value is not an object but matches the
 * supplied 'type_mask', return a NULL instead.  Otherwise throw a TypeError.
 */
DUK_INTERNAL duk_hobject *duk_require_hobject_accept_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t type_mask) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__get_hobject_promote_mask_raw(thr, idx, type_mask | DUK_TYPE_MASK_THROW);
}

DUK_INTERNAL duk_hobject *duk_get_hobject_with_class(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t classnum) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_DISABLE(classnum >= 0);  /* unsigned */
	DUK_ASSERT(classnum <= DUK_HOBJECT_CLASS_MAX);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(h != NULL && DUK_HOBJECT_GET_CLASS_NUMBER(h) != classnum)) {
		h = NULL;
	}
	return h;
}

DUK_INTERNAL duk_hobject *duk_require_hobject_with_class(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t classnum) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_DISABLE(classnum >= 0);  /* unsigned */
	DUK_ASSERT(classnum <= DUK_HOBJECT_CLASS_MAX);

	h = (duk_hobject *) duk__get_tagged_heaphdr_raw(thr, idx, DUK_TAG_OBJECT);
	if (DUK_UNLIKELY(!(h != NULL && DUK_HOBJECT_GET_CLASS_NUMBER(h) == classnum))) {
		duk_hstring *h_class;
		h_class = DUK_HTHREAD_GET_STRING(thr, DUK_HOBJECT_CLASS_NUMBER_TO_STRIDX(classnum));
		DUK_UNREF(h_class);

		DUK_ERROR_REQUIRE_TYPE_INDEX(thr, idx, (const char *) DUK_HSTRING_GET_DATA(h_class), DUK_STR_UNEXPECTED_TYPE);
		DUK_WO_NORETURN(return NULL;);
	}
	return h;
}

DUK_EXTERNAL duk_size_t duk_get_length(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL:
	case DUK_TAG_BOOLEAN:
	case DUK_TAG_POINTER:
		return 0;
#if defined(DUK_USE_PREFER_SIZE)
	/* String and buffer have a virtual non-configurable .length property
	 * which is within size_t range so it can be looked up without specific
	 * type checks.  Lightfuncs inherit from %NativeFunctionPrototype%
	 * which provides an inherited .length accessor; it could be overwritten
	 * to produce unexpected types or values, but just number convert and
	 * duk_size_t cast for now.
	 */
	case DUK_TAG_STRING:
	case DUK_TAG_BUFFER:
	case DUK_TAG_LIGHTFUNC: {
		duk_size_t ret;
		duk_get_prop_stridx(thr, idx, DUK_STRIDX_LENGTH);
		ret = (duk_size_t) duk_to_number_m1(thr);
		duk_pop_unsafe(thr);
		return ret;
	}
#else  /* DUK_USE_PREFER_SIZE */
	case DUK_TAG_STRING: {
		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			return 0;
		}
		return (duk_size_t) DUK_HSTRING_GET_CHARLEN(h);
	}
	case DUK_TAG_BUFFER: {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		return (duk_size_t) DUK_HBUFFER_GET_SIZE(h);
	}
	case DUK_TAG_LIGHTFUNC: {
		/* We could look up the length from the lightfunc duk_tval,
		 * but since Duktape 2.2 lightfunc .length comes from
		 * %NativeFunctionPrototype% which can be overridden, so
		 * look up the property explicitly.
		 */
		duk_size_t ret;
		duk_get_prop_stridx(thr, idx, DUK_STRIDX_LENGTH);
		ret = (duk_size_t) duk_to_number_m1(thr);
		duk_pop_unsafe(thr);
		return ret;
	}
#endif  /* DUK_USE_PREFER_SIZE */
	case DUK_TAG_OBJECT: {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		return (duk_size_t) duk_hobject_get_length(thr, h);
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default:
		/* number or 'unused' */
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv) || DUK_TVAL_IS_UNUSED(tv));
		return 0;
	}

	DUK_UNREACHABLE();
}

/*
 *  duk_known_xxx() helpers
 *
 *  Used internally when we're 100% sure that a certain index is valid and
 *  contains an object of a certain type.  For example, if we duk_push_object()
 *  we can then safely duk_known_hobject(thr, -1).  These helpers just assert
 *  for the index and type, and if the assumptions are not valid, memory unsafe
 *  behavior happens.
 */

DUK_LOCAL duk_heaphdr *duk__known_heaphdr(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_heaphdr *h;

	DUK_CTX_ASSERT_VALID(thr);
	if (idx < 0) {
		tv = thr->valstack_top + idx;
	} else {
		tv = thr->valstack_bottom + idx;
	}
	DUK_ASSERT(tv >= thr->valstack_bottom);
	DUK_ASSERT(tv < thr->valstack_top);
	h = DUK_TVAL_GET_HEAPHDR(tv);
	DUK_ASSERT(h != NULL);
	return h;
}

DUK_INTERNAL duk_hstring *duk_known_hstring(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_hstring(thr, idx) != NULL);
	return (duk_hstring *) duk__known_heaphdr(thr, idx);
}

DUK_INTERNAL duk_hobject *duk_known_hobject(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_hobject(thr, idx) != NULL);
	return (duk_hobject *) duk__known_heaphdr(thr, idx);
}

DUK_INTERNAL duk_hbuffer *duk_known_hbuffer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_hbuffer(thr, idx) != NULL);
	return (duk_hbuffer *) duk__known_heaphdr(thr, idx);
}

DUK_INTERNAL duk_hcompfunc *duk_known_hcompfunc(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_hcompfunc(thr, idx) != NULL);
	return (duk_hcompfunc *) duk__known_heaphdr(thr, idx);
}

DUK_INTERNAL duk_hnatfunc *duk_known_hnatfunc(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_hnatfunc(thr, idx) != NULL);
	return (duk_hnatfunc *) duk__known_heaphdr(thr, idx);
}

DUK_EXTERNAL void duk_set_length(duk_hthread *thr, duk_idx_t idx, duk_size_t len) {
	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_normalize_index(thr, idx);
	duk_push_uint(thr, (duk_uint_t) len);
	duk_put_prop_stridx(thr, idx, DUK_STRIDX_LENGTH);
}

/*
 *  Conversions and coercions
 *
 *  The conversion/coercions are in-place operations on the value stack.
 *  Some operations are implemented here directly, while others call a
 *  helper in duk_js_ops.c after validating arguments.
 */

/* E5 Section 8.12.8 */

DUK_LOCAL duk_bool_t duk__defaultvalue_coerce_attempt(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t func_stridx) {
	if (duk_get_prop_stridx(thr, idx, func_stridx)) {
		/* [ ... func ] */
		if (duk_is_callable(thr, -1)) {
			duk_dup(thr, idx);         /* -> [ ... func this ] */
			duk_call_method(thr, 0);     /* -> [ ... retval ] */
			if (duk_is_primitive(thr, -1)) {
				duk_replace(thr, idx);
				return 1;
			}
			/* [ ... retval ]; popped below */
		}
	}
	duk_pop_unsafe(thr);  /* [ ... func/retval ] -> [ ... ] */
	return 0;
}

DUK_EXTERNAL void duk_to_undefined(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv);  /* side effects */
}

DUK_EXTERNAL void duk_to_null(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	DUK_TVAL_SET_NULL_UPDREF(thr, tv);  /* side effects */
}

/* E5 Section 9.1 */
DUK_LOCAL const char * const duk__toprim_hint_strings[3] = {
	"default", "string", "number"
};
DUK_LOCAL void duk__to_primitive_helper(duk_hthread *thr, duk_idx_t idx, duk_int_t hint, duk_bool_t check_symbol) {
	/* Inline initializer for coercers[] is not allowed by old compilers like BCC. */
	duk_small_uint_t coercers[2];

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(hint == DUK_HINT_NONE || hint == DUK_HINT_NUMBER || hint == DUK_HINT_STRING);

	idx = duk_require_normalize_index(thr, idx);

	/* If already primitive, return as is. */
	if (!duk_check_type_mask(thr, idx, DUK_TYPE_MASK_OBJECT |
	                                   DUK_TYPE_MASK_LIGHTFUNC |
	                                   DUK_TYPE_MASK_BUFFER)) {
		DUK_ASSERT(!duk_is_buffer(thr, idx));  /* duk_to_string() relies on this behavior */
		return;
	}

	/* @@toPrimitive lookup.  Also do for plain buffers and lightfuncs
	 * which mimic objects.
	 */
	if (check_symbol && duk_get_method_stridx(thr, idx, DUK_STRIDX_WELLKNOWN_SYMBOL_TO_PRIMITIVE)) {
		DUK_ASSERT(hint >= 0 && (duk_size_t) hint < sizeof(duk__toprim_hint_strings) / sizeof(const char *));
		duk_dup(thr, idx);
		duk_push_string(thr, duk__toprim_hint_strings[hint]);
		duk_call_method(thr, 1);  /* [ ... method value hint ] -> [ ... res] */
		if (duk_check_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT |
	                                         DUK_TYPE_MASK_LIGHTFUNC |
		                                 DUK_TYPE_MASK_BUFFER)) {
			goto fail;
		}
		duk_replace(thr, idx);
		return;
	}

	/* Objects are coerced based on E5 specification.
	 * Lightfuncs are coerced because they behave like
	 * objects even if they're internally a primitive
	 * type.  Same applies to plain buffers, which behave
	 * like ArrayBuffer objects since Duktape 2.x.
	 */

	/* Hint magic for Date is unnecessary in ES2015 because of
	 * Date.prototype[@@toPrimitive].  However, it is needed if
	 * symbol support is not enabled.
	 */
#if defined(DUK_USE_SYMBOL_BUILTIN)
	if (hint == DUK_HINT_NONE) {
		hint = DUK_HINT_NUMBER;
	}
#else  /* DUK_USE_SYMBOL_BUILTIN */
	if (hint == DUK_HINT_NONE) {
		duk_small_uint_t class_number;

		class_number = duk_get_class_number(thr, idx);
		if (class_number == DUK_HOBJECT_CLASS_DATE) {
			hint = DUK_HINT_STRING;
		} else {
			hint = DUK_HINT_NUMBER;
		}
	}
#endif  /* DUK_USE_SYMBOL_BUILTIN */

	coercers[0] = DUK_STRIDX_VALUE_OF;
	coercers[1] = DUK_STRIDX_TO_STRING;
	if (hint == DUK_HINT_STRING) {
		coercers[0] = DUK_STRIDX_TO_STRING;
		coercers[1] = DUK_STRIDX_VALUE_OF;
	}

	if (duk__defaultvalue_coerce_attempt(thr, idx, coercers[0])) {
		DUK_ASSERT(!duk_is_buffer(thr, idx));  /* duk_to_string() relies on this behavior */
		return;
	}

	if (duk__defaultvalue_coerce_attempt(thr, idx, coercers[1])) {
		DUK_ASSERT(!duk_is_buffer(thr, idx));  /* duk_to_string() relies on this behavior */
		return;
	}

 fail:
	DUK_ERROR_TYPE(thr, DUK_STR_TOPRIMITIVE_FAILED);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_to_primitive(duk_hthread *thr, duk_idx_t idx, duk_int_t hint) {
	duk__to_primitive_helper(thr, idx, hint, 1 /*check_symbol*/);
}

#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL void duk_to_primitive_ordinary(duk_hthread *thr, duk_idx_t idx, duk_int_t hint) {
	duk__to_primitive_helper(thr, idx, hint, 0 /*check_symbol*/);
}
#endif

/* E5 Section 9.2 */
DUK_EXTERNAL duk_bool_t duk_to_boolean(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_bool_t val;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_ASSERT(tv != NULL);

	val = duk_js_toboolean(tv);
	DUK_ASSERT(val == 0 || val == 1);

	/* Note: no need to re-lookup tv, conversion is side effect free. */
	DUK_ASSERT(tv != NULL);
	DUK_TVAL_SET_BOOLEAN_UPDREF(thr, tv, val);  /* side effects */
	return val;
}

DUK_INTERNAL duk_bool_t duk_to_boolean_top_pop(duk_hthread *thr) {
	duk_tval *tv;
	duk_bool_t val;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, -1);
	DUK_ASSERT(tv != NULL);

	val = duk_js_toboolean(tv);
	DUK_ASSERT(val == 0 || val == 1);

	duk_pop_unsafe(thr);
	return val;
}

DUK_EXTERNAL duk_double_t duk_to_number(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_double_t d;

	DUK_ASSERT_API_ENTRY(thr);

	/* XXX: No need to normalize; the whole operation could be inlined here to
	 * avoid 'tv' re-lookup.
	 */
	idx = duk_require_normalize_index(thr, idx);
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_ASSERT(tv != NULL);
	d = duk_js_tonumber(thr, tv);  /* XXX: fastint coercion? now result will always be a non-fastint */

	/* ToNumber() may have side effects so must relookup 'tv'. */
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv, d);  /* side effects */
	return d;
}

DUK_INTERNAL duk_double_t duk_to_number_m1(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_to_number(thr, -1);
}
DUK_INTERNAL duk_double_t duk_to_number_m2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_to_number(thr, -2);
}

DUK_INTERNAL duk_double_t duk_to_number_tval(duk_hthread *thr, duk_tval *tv) {
#if defined(DUK_USE_PREFER_SIZE)
	duk_double_t res;

	DUK_ASSERT_API_ENTRY(thr);

	duk_push_tval(thr, tv);
	res = duk_to_number_m1(thr);
	duk_pop_unsafe(thr);
	return res;
#else
	duk_double_t res;
	duk_tval *tv_dst;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__ASSERT_SPACE();

	tv_dst = thr->valstack_top++;
	DUK_TVAL_SET_TVAL(tv_dst, tv);
	DUK_TVAL_INCREF(thr, tv_dst);  /* decref not necessary */
	res = duk_to_number_m1(thr);  /* invalidates tv_dst */

	tv_dst = --thr->valstack_top;
	DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_dst));
	DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv_dst));  /* plain number */
	DUK_TVAL_SET_UNDEFINED(tv_dst);  /* valstack init policy */

	return res;
#endif
}

/* XXX: combine all the integer conversions: they share everything
 * but the helper function for coercion.
 */

typedef duk_double_t (*duk__toint_coercer)(duk_hthread *thr, duk_tval *tv);

DUK_LOCAL duk_double_t duk__to_int_uint_helper(duk_hthread *thr, duk_idx_t idx, duk__toint_coercer coerce_func) {
	duk_tval *tv;
	duk_double_t d;

	DUK_CTX_ASSERT_VALID(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);

#if defined(DUK_USE_FASTINT)
	/* If argument is a fastint, guarantee that it remains one.
	 * There's no downgrade check for other cases.
	 */
	if (DUK_TVAL_IS_FASTINT(tv)) {
		/* XXX: Unnecessary conversion back and forth. */
		return (duk_double_t) DUK_TVAL_GET_FASTINT(tv);
	}
#endif
	d = coerce_func(thr, tv);

	/* XXX: fastint? */

	/* Relookup in case coerce_func() has side effects, e.g. ends up coercing an object */
	tv = duk_require_tval(thr, idx);
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv, d);  /* side effects */
	return d;
}

DUK_EXTERNAL duk_int_t duk_to_int(duk_hthread *thr, duk_idx_t idx) {
	/* Value coercion (in stack): ToInteger(), E5 Section 9.4,
	 * API return value coercion: custom.
	 */
	DUK_ASSERT_API_ENTRY(thr);
	(void) duk__to_int_uint_helper(thr, idx, duk_js_tointeger);
	return (duk_int_t) duk__api_coerce_d2i(thr, idx, 0 /*def_value*/, 0 /*require*/);
}

DUK_EXTERNAL duk_uint_t duk_to_uint(duk_hthread *thr, duk_idx_t idx) {
	/* Value coercion (in stack): ToInteger(), E5 Section 9.4,
	 * API return value coercion: custom.
	 */
	DUK_ASSERT_API_ENTRY(thr);
	(void) duk__to_int_uint_helper(thr, idx, duk_js_tointeger);
	return (duk_uint_t) duk__api_coerce_d2ui(thr, idx, 0 /*def_value*/, 0 /*require*/);
}

DUK_EXTERNAL duk_int32_t duk_to_int32(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_int32_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	ret = duk_js_toint32(thr, tv);

	/* Relookup in case coerce_func() has side effects, e.g. ends up coercing an object */
	tv = duk_require_tval(thr, idx);
	DUK_TVAL_SET_I32_UPDREF(thr, tv, ret);  /* side effects */
	return ret;
}

DUK_EXTERNAL duk_uint32_t duk_to_uint32(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_uint32_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	ret = duk_js_touint32(thr, tv);

	/* Relookup in case coerce_func() has side effects, e.g. ends up coercing an object */
	tv = duk_require_tval(thr, idx);
	DUK_TVAL_SET_U32_UPDREF(thr, tv, ret);  /* side effects */
	return ret;
}

DUK_EXTERNAL duk_uint16_t duk_to_uint16(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_uint16_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	ret = duk_js_touint16(thr, tv);

	/* Relookup in case coerce_func() has side effects, e.g. ends up coercing an object */
	tv = duk_require_tval(thr, idx);
	DUK_TVAL_SET_U32_UPDREF(thr, tv, ret);  /* side effects */
	return ret;
}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
/* Special coercion for Uint8ClampedArray. */
DUK_INTERNAL duk_uint8_t duk_to_uint8clamped(duk_hthread *thr, duk_idx_t idx) {
	duk_double_t d;
	duk_double_t t;
	duk_uint8_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	/* XXX: Simplify this algorithm, should be possible to come up with
	 * a shorter and faster algorithm by inspecting IEEE representation
	 * directly.
	 */

	d = duk_to_number(thr, idx);
	if (d <= 0.0) {
		return 0;
	} else if (d >= 255) {
		return 255;
	} else if (DUK_ISNAN(d)) {
		/* Avoid NaN-to-integer coercion as it is compiler specific. */
		return 0;
	}

	t = d - DUK_FLOOR(d);
	if (duk_double_equals(t, 0.5)) {
		/* Exact halfway, round to even. */
		ret = (duk_uint8_t) d;
		ret = (ret + 1) & 0xfe;  /* Example: d=3.5, t=0.5 -> ret = (3 + 1) & 0xfe = 4 & 0xfe = 4
		                          * Example: d=4.5, t=0.5 -> ret = (4 + 1) & 0xfe = 5 & 0xfe = 4
		                          */
	} else {
		/* Not halfway, round to nearest. */
		ret = (duk_uint8_t) (d + 0.5);
	}
	return ret;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

DUK_EXTERNAL const char *duk_to_lstring(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	DUK_ASSERT_API_ENTRY(thr);

	(void) duk_to_string(thr, idx);
	DUK_ASSERT(duk_is_string(thr, idx));
	return duk_require_lstring(thr, idx, out_len);
}

DUK_LOCAL duk_ret_t duk__safe_to_string_raw(duk_hthread *thr, void *udata) {
	DUK_CTX_ASSERT_VALID(thr);
	DUK_UNREF(udata);

	(void) duk_to_string(thr, -1);
	return 1;
}

DUK_EXTERNAL const char *duk_safe_to_lstring(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_len) {
	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);

	/* We intentionally ignore the duk_safe_call() return value and only
	 * check the output type.  This way we don't also need to check that
	 * the returned value is indeed a string in the success case.
	 */

	duk_dup(thr, idx);
	(void) duk_safe_call(thr, duk__safe_to_string_raw, NULL /*udata*/, 1 /*nargs*/, 1 /*nrets*/);
	if (!duk_is_string(thr, -1)) {
		/* Error: try coercing error to string once. */
		(void) duk_safe_call(thr, duk__safe_to_string_raw, NULL /*udata*/, 1 /*nargs*/, 1 /*nrets*/);
		if (!duk_is_string(thr, -1)) {
			/* Double error */
			duk_pop_unsafe(thr);
			duk_push_hstring_stridx(thr, DUK_STRIDX_UC_ERROR);
		} else {
			;
		}
	} else {
		/* String; may be a symbol, accepted. */
		;
	}
	DUK_ASSERT(duk_is_string(thr, -1));

	duk_replace(thr, idx);
	DUK_ASSERT(duk_get_string(thr, idx) != NULL);
	return duk_get_lstring(thr, idx, out_len);
}

DUK_EXTERNAL const char *duk_to_stacktrace(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	idx = duk_require_normalize_index(thr, idx);

	/* The expected argument to the call is an Error object.  The stack
	 * trace is extracted without an inheritance-based instanceof check
	 * so that one can also extract the stack trace of a foreign error
	 * created in another Realm.  Accept only a string .stack property.
	 */
	if (duk_is_object(thr, idx)) {
		(void) duk_get_prop_string(thr, idx, "stack");
		if (duk_is_string(thr, -1)) {
			duk_replace(thr, idx);
		} else {
			duk_pop(thr);
		}
	}

	return duk_to_string(thr, idx);
}

DUK_LOCAL duk_ret_t duk__safe_to_stacktrace_raw(duk_hthread *thr, void *udata) {
	DUK_CTX_ASSERT_VALID(thr);
	DUK_UNREF(udata);

	(void) duk_to_stacktrace(thr, -1);

	return 1;
}

DUK_EXTERNAL const char *duk_safe_to_stacktrace(duk_hthread *thr, duk_idx_t idx) {
	duk_int_t rc;

	DUK_ASSERT_API_ENTRY(thr);
	idx = duk_require_normalize_index(thr, idx);

	duk_dup(thr, idx);
	rc = duk_safe_call(thr, duk__safe_to_stacktrace_raw, NULL /*udata*/, 1 /*nargs*/, 1 /*nrets*/);
	if (rc != 0) {
		/* Coercion failed.  Try to coerce the coercion itself error
		 * to a stack trace once.  If that also fails, return a fixed,
		 * preallocated 'Error' string to avoid potential infinite loop.
		 */
		rc = duk_safe_call(thr, duk__safe_to_stacktrace_raw, NULL /*udata*/, 1 /*nargs*/, 1 /*nrets*/);
		if (rc != 0) {
			duk_pop_unsafe(thr);
			duk_push_hstring_stridx(thr, DUK_STRIDX_UC_ERROR);
		}
	}
	duk_replace(thr, idx);

	return duk_get_string(thr, idx);
}

DUK_INTERNAL duk_hstring *duk_to_property_key_hstring(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);

	duk_to_primitive(thr, idx, DUK_HINT_STRING);  /* needed for e.g. Symbol objects */
	h = duk_get_hstring(thr, idx);
	if (h == NULL) {
		/* The "is string?" check may seem unnecessary, but as things
		 * are duk_to_hstring() invokes ToString() which fails for
		 * symbols.  But since symbols are already strings for Duktape
		 * C API, we check for that before doing the coercion.
		 */
		h = duk_to_hstring(thr, idx);
	}
	DUK_ASSERT(h != NULL);
	return h;
}

#if defined(DUK_USE_DEBUGGER_SUPPORT)  /* only needed by debugger for now */
DUK_INTERNAL duk_hstring *duk_safe_to_hstring(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	(void) duk_safe_to_string(thr, idx);
	DUK_ASSERT(duk_is_string(thr, idx));
	DUK_ASSERT(duk_get_hstring(thr, idx) != NULL);
	return duk_known_hstring(thr, idx);
}
#endif

/* Push Object.prototype.toString() output for 'tv'. */
DUK_INTERNAL void duk_push_class_string_tval(duk_hthread *thr, duk_tval *tv, duk_bool_t avoid_side_effects) {
	duk_hobject *h_obj;
	duk_small_uint_t classnum;
	duk_small_uint_t stridx;
	duk_tval tv_tmp;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(tv != NULL);

	/* Stabilize 'tv', duk_push_literal() may trigger side effects. */
	DUK_TVAL_SET_TVAL(&tv_tmp, tv);
	tv = &tv_tmp;

	/* Conceptually for any non-undefined/null value we should do a
	 * ToObject() coercion and look up @@toStringTag (from the object
	 * prototype) to see if a custom result should be used, with the
	 * exception of Arrays which are handled specially first.
	 *
	 * We'd like to avoid the actual conversion, but even for primitive
	 * types the prototype may have @@toStringTag.  What's worse, the
	 * @@toStringTag property may be a getter that must get the object
	 * coerced value (not the prototype) as its 'this' binding.
	 *
	 * For now, do an actual object coercion.  This could be avoided by
	 * doing a side effect free lookup to see if a getter would be invoked.
	 * If not, the value can be read directly and the object coercion could
	 * be avoided.  This may not be worth it in practice, because
	 * Object.prototype.toString() is usually not performance critical.
	 */

	duk_push_literal(thr, "[object ");  /* -> [ ... "[object" ] */

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNUSED:  /* Treat like 'undefined', shouldn't happen. */
	case DUK_TAG_UNDEFINED: {
		duk_push_hstring_stridx(thr, DUK_STRIDX_UC_UNDEFINED);
		goto finish;
	}
	case DUK_TAG_NULL: {
		duk_push_hstring_stridx(thr, DUK_STRIDX_UC_NULL);
		goto finish;
	}
	}

	duk_push_tval(thr, tv);
	tv = NULL;  /* Invalidated by ToObject(). */
	h_obj = duk_to_hobject(thr, -1);
	DUK_ASSERT(h_obj != NULL);
	if (duk_js_isarray_hobject(h_obj)) {
		stridx = DUK_STRIDX_UC_ARRAY;
	} else {
		/* [ ... "[object" obj ] */

#if defined(DUK_USE_SYMBOL_BUILTIN)
		/* XXX: better handling with avoid_side_effects == 1; lookup tval
		 * without Proxy or getter side effects, and use it in sanitized
		 * form if it's a string.
		 */
		if (!avoid_side_effects) {
			(void) duk_get_prop_stridx(thr, -1, DUK_STRIDX_WELLKNOWN_SYMBOL_TO_STRING_TAG);
			if (duk_is_string_notsymbol(thr, -1)) {
				duk_remove_m2(thr);
				goto finish;
			}
			duk_pop_unsafe(thr);
		}
#else
		DUK_UNREF(avoid_side_effects);
#endif

		classnum = DUK_HOBJECT_GET_CLASS_NUMBER(h_obj);
		stridx = DUK_HOBJECT_CLASS_NUMBER_TO_STRIDX(classnum);
	}
	duk_pop_unsafe(thr);
	duk_push_hstring_stridx(thr, stridx);

 finish:
	/* [ ... "[object" tag ] */
	duk_push_literal(thr, "]");
	duk_concat(thr, 3);  /* [ ... "[object" tag "]" ] -> [ ... res ] */
}

/* XXX: other variants like uint, u32 etc */
DUK_INTERNAL duk_int_t duk_to_int_clamped_raw(duk_hthread *thr, duk_idx_t idx, duk_int_t minval, duk_int_t maxval, duk_bool_t *out_clamped) {
	duk_tval *tv;
	duk_tval tv_tmp;
	duk_double_t d, dmin, dmax;
	duk_int_t res;
	duk_bool_t clamped = 0;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	d = duk_js_tointeger(thr, tv);  /* E5 Section 9.4, ToInteger() */

	dmin = (duk_double_t) minval;
	dmax = (duk_double_t) maxval;

	if (d < dmin) {
		clamped = 1;
		res = minval;
		d = dmin;
	} else if (d > dmax) {
		clamped = 1;
		res = maxval;
		d = dmax;
	} else {
		res = (duk_int_t) d;
	}
	DUK_UNREF(d);  /* SCANBUILD: with suitable dmin/dmax limits 'd' is unused */
	/* 'd' and 'res' agree here */

	/* Relookup in case duk_js_tointeger() ends up e.g. coercing an object. */
	tv = duk_get_tval(thr, idx);
	DUK_ASSERT(tv != NULL);  /* not popped by side effect */
	DUK_TVAL_SET_TVAL(&tv_tmp, tv);
#if defined(DUK_USE_FASTINT)
#if (DUK_INT_MAX <= 0x7fffffffL)
	DUK_TVAL_SET_I32(tv, res);
#else
	/* Clamping needed if duk_int_t is 64 bits. */
	if (res >= DUK_FASTINT_MIN && res <= DUK_FASTINT_MAX) {
		DUK_TVAL_SET_FASTINT(tv, res);
	} else {
		DUK_TVAL_SET_NUMBER(tv, d);
	}
#endif
#else
	DUK_TVAL_SET_NUMBER(tv, d);  /* no need to incref */
#endif
	DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */

	if (out_clamped) {
		*out_clamped = clamped;
	} else {
		/* coerced value is updated to value stack even when RangeError thrown */
		if (clamped) {
			DUK_ERROR_RANGE(thr, DUK_STR_NUMBER_OUTSIDE_RANGE);
			DUK_WO_NORETURN(return 0;);
		}
	}

	return res;
}

DUK_INTERNAL duk_int_t duk_to_int_clamped(duk_hthread *thr, duk_idx_t idx, duk_idx_t minval, duk_idx_t maxval) {
	duk_bool_t dummy;

	DUK_ASSERT_API_ENTRY(thr);

	return duk_to_int_clamped_raw(thr, idx, minval, maxval, &dummy);
}

DUK_INTERNAL duk_int_t duk_to_int_check_range(duk_hthread *thr, duk_idx_t idx, duk_int_t minval, duk_int_t maxval) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_to_int_clamped_raw(thr, idx, minval, maxval, NULL);  /* out_clamped==NULL -> RangeError if outside range */
}

DUK_EXTERNAL const char *duk_to_string(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED: {
		duk_push_hstring_stridx(thr, DUK_STRIDX_LC_UNDEFINED);
		break;
	}
	case DUK_TAG_NULL: {
		duk_push_hstring_stridx(thr, DUK_STRIDX_LC_NULL);
		break;
	}
	case DUK_TAG_BOOLEAN: {
		if (DUK_TVAL_GET_BOOLEAN(tv)) {
			duk_push_hstring_stridx(thr, DUK_STRIDX_TRUE);
		} else {
			duk_push_hstring_stridx(thr, DUK_STRIDX_FALSE);
		}
		break;
	}
	case DUK_TAG_STRING: {
		/* Nop for actual strings, TypeError for Symbols.
		 * Because various internals rely on ToString() coercion of
		 * internal strings, -allow- (NOP) string coercion for hidden
		 * symbols.
		 */
#if 1
		duk_hstring *h;
		h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			DUK_ERROR_TYPE(thr, DUK_STR_CANNOT_STRING_COERCE_SYMBOL);
			DUK_WO_NORETURN(goto skip_replace;);
		} else {
			goto skip_replace;
		}
#else
		goto skip_replace;
#endif
		break;
	}
	case DUK_TAG_BUFFER: /* Go through Uint8Array.prototype.toString() for coercion. */
	case DUK_TAG_OBJECT: {
		/* Plain buffers: go through ArrayBuffer.prototype.toString()
		 * for coercion.
		 *
		 * Symbol objects: duk_to_primitive() results in a plain symbol
		 * value, and duk_to_string() then causes a TypeError.
		 */
		duk_to_primitive(thr, idx, DUK_HINT_STRING);
		DUK_ASSERT(!duk_is_buffer(thr, idx));  /* ToPrimitive() must guarantee */
		DUK_ASSERT(!duk_is_object(thr, idx));
		return duk_to_string(thr, idx);  /* Note: recursive call */
	}
	case DUK_TAG_POINTER: {
		void *ptr = DUK_TVAL_GET_POINTER(tv);
		if (ptr != NULL) {
			duk_push_sprintf(thr, DUK_STR_FMT_PTR, (void *) ptr);
		} else {
			/* Represent a null pointer as 'null' to be consistent with
			 * the JX format variant.  Native '%p' format for a NULL
			 * pointer may be e.g. '(nil)'.
			 */
			duk_push_hstring_stridx(thr, DUK_STRIDX_LC_NULL);
		}
		break;
	}
	case DUK_TAG_LIGHTFUNC: {
		/* Should match Function.prototype.toString() */
		duk_push_lightfunc_tostring(thr, tv);
		break;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default: {
		/* number */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		duk_push_tval(thr, tv);
		duk_numconv_stringify(thr,
		                      10 /*radix*/,
		                      0 /*precision:shortest*/,
		                      0 /*force_exponential*/);
		break;
	}
	}

	duk_replace(thr, idx);

 skip_replace:
	DUK_ASSERT(duk_is_string(thr, idx));
	return duk_require_string(thr, idx);
}

DUK_INTERNAL duk_hstring *duk_to_hstring(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *ret;

	DUK_ASSERT_API_ENTRY(thr);

	duk_to_string(thr, idx);
	ret = duk_get_hstring(thr, idx);
	DUK_ASSERT(ret != NULL);
	return ret;
}

DUK_INTERNAL duk_hstring *duk_to_hstring_m1(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_to_hstring(thr, -1);
}

DUK_INTERNAL duk_hstring *duk_to_hstring_acceptsymbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *ret;

	DUK_ASSERT_API_ENTRY(thr);

	ret = duk_get_hstring(thr, idx);
	if (DUK_UNLIKELY(ret && DUK_HSTRING_HAS_SYMBOL(ret))) {
		return ret;
	}
	return duk_to_hstring(thr, idx);
}

/* Convert a plain buffer or any buffer object into a string, using the buffer
 * bytes 1:1 in the internal string representation.  For views the active byte
 * slice (not element slice interpreted as an initializer) is used.  This is
 * necessary in Duktape 2.x because ToString(plainBuffer) no longer creates a
 * string with the same bytes as in the buffer but rather (usually)
 * '[object ArrayBuffer]'.
 */
DUK_EXTERNAL const char *duk_buffer_to_string(duk_hthread *thr, duk_idx_t idx) {
	void *ptr_src;
	duk_size_t len;
	const char *res;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);

	ptr_src = duk_require_buffer_data(thr, idx, &len);
	DUK_ASSERT(ptr_src != NULL || len == 0);

	res = duk_push_lstring(thr, (const char *) ptr_src, len);
	duk_replace(thr, idx);
	return res;
}

DUK_EXTERNAL void *duk_to_buffer_raw(duk_hthread *thr, duk_idx_t idx, duk_size_t *out_size, duk_uint_t mode) {
	duk_hbuffer *h_buf;
	const duk_uint8_t *src_data;
	duk_size_t src_size;
	duk_uint8_t *dst_data;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);

	h_buf = duk_get_hbuffer(thr, idx);
	if (h_buf != NULL) {
		/* Buffer is kept as is, with the fixed/dynamic nature of the
		 * buffer only changed if requested.  An external buffer
		 * is converted into a non-external dynamic buffer in a
		 * duk_to_dynamic_buffer() call.
		 */
		duk_uint_t tmp;
		duk_uint8_t *tmp_ptr;

		tmp_ptr = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_buf);
		src_data = (const duk_uint8_t *) tmp_ptr;
		src_size = DUK_HBUFFER_GET_SIZE(h_buf);

		tmp = (DUK_HBUFFER_HAS_DYNAMIC(h_buf) ? DUK_BUF_MODE_DYNAMIC : DUK_BUF_MODE_FIXED);
		if ((tmp == mode && !DUK_HBUFFER_HAS_EXTERNAL(h_buf)) ||
		    mode == DUK_BUF_MODE_DONTCARE) {
			/* Note: src_data may be NULL if input is a zero-size
			 * dynamic buffer.
			 */
			dst_data = tmp_ptr;
			goto skip_copy;
		}
	} else {
		/* Non-buffer value is first ToString() coerced, then converted
		 * to a buffer (fixed buffer is used unless a dynamic buffer is
		 * explicitly requested).  Symbols are rejected with a TypeError.
		 * XXX: C API could maybe allow symbol-to-buffer coercion?
		 */
		src_data = (const duk_uint8_t *) duk_to_lstring(thr, idx, &src_size);
	}

	dst_data = (duk_uint8_t *) duk_push_buffer(thr, src_size, (mode == DUK_BUF_MODE_DYNAMIC) /*dynamic*/);
	/* dst_data may be NULL if size is zero. */
	duk_memcpy_unsafe((void *) dst_data, (const void *) src_data, (size_t) src_size);

	duk_replace(thr, idx);
 skip_copy:

	if (out_size) {
		*out_size = src_size;
	}
	return dst_data;
}

DUK_EXTERNAL void *duk_to_pointer(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	void *res;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL:
	case DUK_TAG_BOOLEAN:
		res = NULL;
		break;
	case DUK_TAG_POINTER:
		res = DUK_TVAL_GET_POINTER(tv);
		break;
	case DUK_TAG_STRING:
	case DUK_TAG_OBJECT:
	case DUK_TAG_BUFFER:
		/* Heap allocated: return heap pointer which is NOT useful
		 * for the caller, except for debugging.
		 */
		res = (void *) DUK_TVAL_GET_HEAPHDR(tv);
		break;
	case DUK_TAG_LIGHTFUNC:
		/* Function pointers do not always cast correctly to void *
		 * (depends on memory and segmentation model for instance),
		 * so they coerce to NULL.
		 */
		res = NULL;
		break;
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default:
		/* number */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		res = NULL;
		break;
	}

	duk_push_pointer(thr, res);
	duk_replace(thr, idx);
	return res;
}

DUK_LOCAL void duk__push_func_from_lightfunc(duk_hthread *thr, duk_c_function func, duk_small_uint_t lf_flags) {
	duk_idx_t nargs;
	duk_uint_t flags = 0;   /* shared flags for a subset of types */
	duk_small_uint_t lf_len;
	duk_hnatfunc *nf;

	nargs = (duk_idx_t) DUK_LFUNC_FLAGS_GET_NARGS(lf_flags);
	if (nargs == DUK_LFUNC_NARGS_VARARGS) {
		nargs = (duk_idx_t) DUK_VARARGS;
	}

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_CONSTRUCTABLE |
	        DUK_HOBJECT_FLAG_CALLABLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_NATFUNC |
	        DUK_HOBJECT_FLAG_NEWENV |
	        DUK_HOBJECT_FLAG_STRICT |
	        DUK_HOBJECT_FLAG_NOTAIL |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION);
	(void) duk__push_c_function_raw(thr, func, nargs, flags, DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE);

	lf_len = DUK_LFUNC_FLAGS_GET_LENGTH(lf_flags);
	if ((duk_idx_t) lf_len != nargs) {
		/* Explicit length is only needed if it differs from 'nargs'. */
		duk_push_int(thr, (duk_int_t) lf_len);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_NONE);
	}

#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	duk_push_lightfunc_name_raw(thr, func, lf_flags);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);
#endif

	nf = duk_known_hnatfunc(thr, -1);
	nf->magic = (duk_int16_t) DUK_LFUNC_FLAGS_GET_MAGIC(lf_flags);
}

DUK_EXTERNAL void duk_to_object(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_uint_t flags = 0;   /* shared flags for a subset of types */
	duk_small_int_t proto = 0;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);
	tv = DUK_GET_TVAL_POSIDX(thr, idx);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
#if !defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	case DUK_TAG_BUFFER:  /* With no bufferobject support, don't object coerce. */
#endif
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL: {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_OBJECT_COERCIBLE);
		DUK_WO_NORETURN(return;);
		break;
	}
	case DUK_TAG_BOOLEAN: {
		flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
		        DUK_HOBJECT_FLAG_FASTREFS |
		        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_BOOLEAN);
		proto = DUK_BIDX_BOOLEAN_PROTOTYPE;
		goto create_object;
	}
	case DUK_TAG_STRING: {
		duk_hstring *h;
		h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
			        DUK_HOBJECT_FLAG_FASTREFS |
			        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_SYMBOL);
			proto = DUK_BIDX_SYMBOL_PROTOTYPE;
		} else {
			flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
			        DUK_HOBJECT_FLAG_FASTREFS |
			        DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ |
			        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_STRING);
			proto = DUK_BIDX_STRING_PROTOTYPE;
		}
		goto create_object;
	}
	case DUK_TAG_OBJECT: {
		/* nop */
		break;
	}
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	case DUK_TAG_BUFFER: {
		/* A plain buffer object coerces to a full ArrayBuffer which
		 * is not fully transparent behavior (ToObject() should be a
		 * nop for an object).  This behavior matches lightfuncs which
		 * also coerce to an equivalent Function object.  There are
		 * also downsides to defining ToObject(plainBuffer) as a no-op;
		 * for example duk_to_hobject() could result in a NULL pointer.
		 */
		duk_hbuffer *h_buf;

		h_buf = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h_buf != NULL);
		duk_hbufobj_push_uint8array_from_plain(thr, h_buf);
		goto replace_value;
	}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
	case DUK_TAG_POINTER: {
		flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
		        DUK_HOBJECT_FLAG_FASTREFS |
		        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_POINTER);
		proto = DUK_BIDX_POINTER_PROTOTYPE;
		goto create_object;
	}
	case DUK_TAG_LIGHTFUNC: {
		/* Lightfunc coerces to a Function instance with concrete
		 * properties.  Since 'length' is virtual for Duktape/C
		 * functions, don't need to define that.  The result is made
		 * extensible to mimic what happens to strings in object
		 * coercion:
		 *
		 *   > Object.isExtensible(Object('foo'))
		 *   true
		 */
		duk_small_uint_t lf_flags;
		duk_c_function func;

		DUK_TVAL_GET_LIGHTFUNC(tv, func, lf_flags);
		duk__push_func_from_lightfunc(thr, func, lf_flags);
		goto replace_value;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default: {
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
		        DUK_HOBJECT_FLAG_FASTREFS |
		        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_NUMBER);
		proto = DUK_BIDX_NUMBER_PROTOTYPE;
		goto create_object;
	}
	}
	DUK_ASSERT(duk_is_object(thr, idx));
	return;

 create_object:
	(void) duk_push_object_helper(thr, flags, proto);

	/* Note: Boolean prototype's internal value property is not writable,
	 * but duk_xdef_prop_stridx() disregards the write protection.  Boolean
	 * instances are immutable.
	 *
	 * String and buffer special behaviors are already enabled which is not
	 * ideal, but a write to the internal value is not affected by them.
	 */
	duk_dup(thr, idx);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);

 replace_value:
	duk_replace(thr, idx);
	DUK_ASSERT(duk_is_object(thr, idx));
}

DUK_INTERNAL duk_hobject *duk_to_hobject(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *ret;

	DUK_ASSERT_API_ENTRY(thr);

	duk_to_object(thr, idx);
	ret = duk_known_hobject(thr, idx);
	return ret;
}

/*
 *  Type checking
 */

DUK_LOCAL duk_bool_t duk__tag_check(duk_hthread *thr, duk_idx_t idx, duk_small_uint_t tag) {
	duk_tval *tv;

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	return (DUK_TVAL_GET_TAG(tv) == tag);
}

DUK_LOCAL duk_bool_t duk__obj_flag_any_default_false(duk_hthread *thr, duk_idx_t idx, duk_uint_t flag_mask) {
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_get_hobject(thr, idx);
	if (obj) {
		return (DUK_HEAPHDR_CHECK_FLAG_BITS((duk_heaphdr *) obj, flag_mask) ? 1 : 0);
	}
	return 0;
}

DUK_INTERNAL duk_int_t duk_get_type_tval(duk_tval *tv) {
	DUK_ASSERT(tv != NULL);

#if defined(DUK_USE_PACKED_TVAL)
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNUSED:
		return DUK_TYPE_NONE;
	case DUK_TAG_UNDEFINED:
		return DUK_TYPE_UNDEFINED;
	case DUK_TAG_NULL:
		return DUK_TYPE_NULL;
	case DUK_TAG_BOOLEAN:
		return DUK_TYPE_BOOLEAN;
	case DUK_TAG_STRING:
		return DUK_TYPE_STRING;
	case DUK_TAG_OBJECT:
		return DUK_TYPE_OBJECT;
	case DUK_TAG_BUFFER:
		return DUK_TYPE_BUFFER;
	case DUK_TAG_POINTER:
		return DUK_TYPE_POINTER;
	case DUK_TAG_LIGHTFUNC:
		return DUK_TYPE_LIGHTFUNC;
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default:
		/* Note: number has no explicit tag (in 8-byte representation) */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		return DUK_TYPE_NUMBER;
	}
#else  /* DUK_USE_PACKED_TVAL */
	DUK_ASSERT(DUK_TVAL_IS_VALID_TAG(tv));
	DUK_ASSERT(sizeof(duk__type_from_tag) / sizeof(duk_uint_t) == DUK_TAG_MAX - DUK_TAG_MIN + 1);
	return (duk_int_t) duk__type_from_tag[DUK_TVAL_GET_TAG(tv) - DUK_TAG_MIN];
#endif  /* DUK_USE_PACKED_TVAL */
}

DUK_EXTERNAL duk_int_t duk_get_type(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	return duk_get_type_tval(tv);
}

#if defined(DUK_USE_VERBOSE_ERRORS) && defined(DUK_USE_PARANOID_ERRORS)
DUK_LOCAL const char * const duk__type_names[] = {
	"none",
	"undefined",
	"null",
	"boolean",
	"number",
	"string",
	"object",
	"buffer",
	"pointer",
	"lightfunc"
};

DUK_INTERNAL const char *duk_get_type_name(duk_hthread *thr, duk_idx_t idx) {
	duk_int_t type_tag;

	DUK_ASSERT_API_ENTRY(thr);

	type_tag = duk_get_type(thr, idx);
	DUK_ASSERT(type_tag >= DUK_TYPE_MIN && type_tag <= DUK_TYPE_MAX);
	DUK_ASSERT(DUK_TYPE_MIN == 0 && sizeof(duk__type_names) / sizeof(const char *) == DUK_TYPE_MAX + 1);

	return duk__type_names[type_tag];
}
#endif  /* DUK_USE_VERBOSE_ERRORS && DUK_USE_PARANOID_ERRORS */

DUK_INTERNAL duk_small_uint_t duk_get_class_number(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_OBJECT:
		obj = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(obj != NULL);
		return DUK_HOBJECT_GET_CLASS_NUMBER(obj);
	case DUK_TAG_BUFFER:
		/* Buffers behave like Uint8Array objects. */
		return DUK_HOBJECT_CLASS_UINT8ARRAY;
	case DUK_TAG_LIGHTFUNC:
		/* Lightfuncs behave like Function objects. */
		return DUK_HOBJECT_CLASS_FUNCTION;
	default:
		/* Primitive or UNUSED, no class number. */
		return DUK_HOBJECT_CLASS_NONE;
	}
}

DUK_EXTERNAL duk_bool_t duk_check_type(duk_hthread *thr, duk_idx_t idx, duk_int_t type) {
	DUK_ASSERT_API_ENTRY(thr);

	return (duk_get_type(thr, idx) == type) ? 1 : 0;
}

DUK_INTERNAL duk_uint_t duk_get_type_mask_tval(duk_tval *tv) {
	DUK_ASSERT(tv != NULL);

#if defined(DUK_USE_PACKED_TVAL)
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNUSED:
		return DUK_TYPE_MASK_NONE;
	case DUK_TAG_UNDEFINED:
		return DUK_TYPE_MASK_UNDEFINED;
	case DUK_TAG_NULL:
		return DUK_TYPE_MASK_NULL;
	case DUK_TAG_BOOLEAN:
		return DUK_TYPE_MASK_BOOLEAN;
	case DUK_TAG_STRING:
		return DUK_TYPE_MASK_STRING;
	case DUK_TAG_OBJECT:
		return DUK_TYPE_MASK_OBJECT;
	case DUK_TAG_BUFFER:
		return DUK_TYPE_MASK_BUFFER;
	case DUK_TAG_POINTER:
		return DUK_TYPE_MASK_POINTER;
	case DUK_TAG_LIGHTFUNC:
		return DUK_TYPE_MASK_LIGHTFUNC;
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default:
		/* Note: number has no explicit tag (in 8-byte representation) */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		return DUK_TYPE_MASK_NUMBER;
	}
#else  /* DUK_USE_PACKED_TVAL */
	DUK_ASSERT(DUK_TVAL_IS_VALID_TAG(tv));
	DUK_ASSERT(sizeof(duk__type_mask_from_tag) / sizeof(duk_uint_t) == DUK_TAG_MAX - DUK_TAG_MIN + 1);
	return duk__type_mask_from_tag[DUK_TVAL_GET_TAG(tv) - DUK_TAG_MIN];
#endif  /* DUK_USE_PACKED_TVAL */
}

DUK_EXTERNAL duk_uint_t duk_get_type_mask(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	return duk_get_type_mask_tval(tv);
}

DUK_EXTERNAL duk_bool_t duk_check_type_mask(duk_hthread *thr, duk_idx_t idx, duk_uint_t mask) {
	DUK_ASSERT_API_ENTRY(thr);

	if (DUK_LIKELY((duk_get_type_mask(thr, idx) & mask) != 0U)) {
		return 1;
	}
	if (mask & DUK_TYPE_MASK_THROW) {
		DUK_ERROR_TYPE(thr, DUK_STR_UNEXPECTED_TYPE);
		DUK_WO_NORETURN(return 0;);
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_undefined(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_UNDEFINED);
}

DUK_EXTERNAL duk_bool_t duk_is_null(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_NULL);
}

DUK_EXTERNAL duk_bool_t duk_is_boolean(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_BOOLEAN);
}

DUK_EXTERNAL duk_bool_t duk_is_number(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	/*
	 *  Number is special because it doesn't have a specific
	 *  tag in the 8-byte representation.
	 */

	/* XXX: shorter version for unpacked representation? */

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	return DUK_TVAL_IS_NUMBER(tv);
}

DUK_EXTERNAL duk_bool_t duk_is_nan(duk_hthread *thr, duk_idx_t idx) {
	/* XXX: This will now return false for non-numbers, even though they would
	 * coerce to NaN (as a general rule).  In particular, duk_get_number()
	 * returns a NaN for non-numbers, so should this function also return
	 * true for non-numbers?
	 */

	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);

	/* XXX: for packed duk_tval an explicit "is number" check is unnecessary */
	if (!DUK_TVAL_IS_NUMBER(tv)) {
		return 0;
	}
	return (duk_bool_t) DUK_ISNAN(DUK_TVAL_GET_NUMBER(tv));
}

DUK_EXTERNAL duk_bool_t duk_is_string(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_STRING);
}

DUK_INTERNAL duk_bool_t duk_is_string_notsymbol(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_get_hstring_notsymbol(thr, idx) != NULL;
}

DUK_EXTERNAL duk_bool_t duk_is_object(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_OBJECT);
}

DUK_EXTERNAL duk_bool_t duk_is_buffer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_BUFFER);
}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_EXTERNAL duk_bool_t duk_is_buffer_data(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_BUFFER(tv)) {
		return 1;
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			return 1;
		}
	}
	return 0;
}
#else  /* DUK_USE_BUFFEROBJECT_SUPPORT */
DUK_EXTERNAL duk_bool_t duk_is_buffer_data(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);

	return duk_is_buffer(thr, idx);
}

#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

DUK_EXTERNAL duk_bool_t duk_is_pointer(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_POINTER);
}

DUK_EXTERNAL duk_bool_t duk_is_lightfunc(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__tag_check(thr, idx, DUK_TAG_LIGHTFUNC);
}

DUK_EXTERNAL duk_bool_t duk_is_symbol(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	DUK_ASSERT_API_ENTRY(thr);
	h = duk_get_hstring(thr, idx);
	/* Use DUK_LIKELY() here because caller may be more likely to type
	 * check an expected symbol than not.
	 */
	if (DUK_LIKELY(h != NULL && DUK_HSTRING_HAS_SYMBOL(h))) {
		return 1;
	}
	return 0;
}

/* IsArray(), returns true for Array instance or Proxy of Array instance. */
DUK_EXTERNAL duk_bool_t duk_is_array(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval(thr, idx);
	if (tv) {
		return duk_js_isarray(tv);
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_function(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		return DUK_HOBJECT_HAS_CALLABLE(h) ? 1 : 0;
	}
	if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		return 1;
	}
	return 0;
}

DUK_INTERNAL duk_bool_t duk_is_callable_tval(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_UNREF(thr);

	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		return DUK_HOBJECT_HAS_CALLABLE(h) ? 1 : 0;
	}
	if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		return 1;
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_constructable(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		return DUK_HOBJECT_HAS_CONSTRUCTABLE(h) ? 1 : 0;
	}
	if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		return 1;
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_c_function(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__obj_flag_any_default_false(thr,
	                                       idx,
	                                       DUK_HOBJECT_FLAG_NATFUNC);
}

DUK_EXTERNAL duk_bool_t duk_is_ecmascript_function(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__obj_flag_any_default_false(thr,
	                                       idx,
	                                       DUK_HOBJECT_FLAG_COMPFUNC);
}

DUK_EXTERNAL duk_bool_t duk_is_bound_function(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__obj_flag_any_default_false(thr,
	                                       idx,
	                                       DUK_HOBJECT_FLAG_BOUNDFUNC);
}

DUK_EXTERNAL duk_bool_t duk_is_thread(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *obj;

	DUK_ASSERT_API_ENTRY(thr);

	obj = duk_get_hobject(thr, idx);
	if (obj) {
		return (DUK_HOBJECT_GET_CLASS_NUMBER(obj) == DUK_HOBJECT_CLASS_THREAD ? 1 : 0);
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_fixed_buffer(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		return (DUK_HBUFFER_HAS_DYNAMIC(h) ? 0 : 1);
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_dynamic_buffer(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		return (DUK_HBUFFER_HAS_DYNAMIC(h) && !DUK_HBUFFER_HAS_EXTERNAL(h) ? 1 : 0);
	}
	return 0;
}

DUK_EXTERNAL duk_bool_t duk_is_external_buffer(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_get_tval_or_unused(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		return (DUK_HBUFFER_HAS_DYNAMIC(h) && DUK_HBUFFER_HAS_EXTERNAL(h) ? 1 : 0);
	}
	return 0;
}

DUK_EXTERNAL duk_errcode_t duk_get_error_code(duk_hthread *thr, duk_idx_t idx) {
	duk_hobject *h;
	duk_uint_t sanity;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_get_hobject(thr, idx);

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (!h) {
			return DUK_ERR_NONE;
		}

		/* XXX: something more convenient? */

		if (h == thr->builtins[DUK_BIDX_EVAL_ERROR_PROTOTYPE]) {
			return DUK_ERR_EVAL_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_RANGE_ERROR_PROTOTYPE]) {
			return DUK_ERR_RANGE_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_REFERENCE_ERROR_PROTOTYPE]) {
			return DUK_ERR_REFERENCE_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_SYNTAX_ERROR_PROTOTYPE]) {
			return DUK_ERR_SYNTAX_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_TYPE_ERROR_PROTOTYPE]) {
			return DUK_ERR_TYPE_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_URI_ERROR_PROTOTYPE]) {
			return DUK_ERR_URI_ERROR;
		}
		if (h == thr->builtins[DUK_BIDX_ERROR_PROTOTYPE]) {
			return DUK_ERR_ERROR;
		}

		h = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h);
	} while (--sanity > 0);

	return DUK_ERR_NONE;
}

/*
 *  Pushers
 */

DUK_INTERNAL void duk_push_tval(duk_hthread *thr, duk_tval *tv) {
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(tv != NULL);

	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_TVAL(tv_slot, tv);
	DUK_TVAL_INCREF(thr, tv);  /* no side effects */
}

DUK_EXTERNAL void duk_push_undefined(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();

	/* Because value stack init policy is 'undefined above top',
	 * we don't need to write, just assert.
	 */
	thr->valstack_top++;
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top - 1));
}

DUK_EXTERNAL void duk_push_null(duk_hthread *thr) {
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_NULL(tv_slot);
}

DUK_EXTERNAL void duk_push_boolean(duk_hthread *thr, duk_bool_t val) {
	duk_tval *tv_slot;
	duk_small_int_t b;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	b = (val ? 1 : 0);  /* ensure value is 1 or 0 (not other non-zero) */
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_BOOLEAN(tv_slot, b);
}

DUK_EXTERNAL void duk_push_true(duk_hthread *thr) {
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_BOOLEAN_TRUE(tv_slot);
}

DUK_EXTERNAL void duk_push_false(duk_hthread *thr) {
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_BOOLEAN_FALSE(tv_slot);
}

/* normalize NaN which may not match our canonical internal NaN */
DUK_EXTERNAL void duk_push_number(duk_hthread *thr, duk_double_t val) {
	duk_tval *tv_slot;
	duk_double_union du;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	du.d = val;
	DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_NUMBER(tv_slot, du.d);
}

DUK_EXTERNAL void duk_push_int(duk_hthread *thr, duk_int_t val) {
#if defined(DUK_USE_FASTINT)
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
#if DUK_INT_MAX <= 0x7fffffffL
	DUK_TVAL_SET_I32(tv_slot, (duk_int32_t) val);
#else
	if (val >= DUK_FASTINT_MIN && val <= DUK_FASTINT_MAX) {
		DUK_TVAL_SET_FASTINT(tv_slot, (duk_int64_t) val);
	} else {
		duk_double_t = (duk_double_t) val;
		DUK_TVAL_SET_NUMBER(tv_slot, d);
	}
#endif
#else  /* DUK_USE_FASTINT */
	duk_tval *tv_slot;
	duk_double_t d;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	d = (duk_double_t) val;
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_NUMBER(tv_slot, d);
#endif  /* DUK_USE_FASTINT */
}

DUK_EXTERNAL void duk_push_uint(duk_hthread *thr, duk_uint_t val) {
#if defined(DUK_USE_FASTINT)
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
#if DUK_UINT_MAX <= 0xffffffffUL
	DUK_TVAL_SET_U32(tv_slot, (duk_uint32_t) val);
#else
	if (val <= DUK_FASTINT_MAX) {  /* val is unsigned so >= 0 */
		/* XXX: take advantage of val being unsigned, no need to mask */
		DUK_TVAL_SET_FASTINT(tv_slot, (duk_int64_t) val);
	} else {
		duk_double_t = (duk_double_t) val;
		DUK_TVAL_SET_NUMBER(tv_slot, d);
	}
#endif
#else  /* DUK_USE_FASTINT */
	duk_tval *tv_slot;
	duk_double_t d;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	d = (duk_double_t) val;
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_NUMBER(tv_slot, d);
#endif  /* DUK_USE_FASTINT */
}

DUK_EXTERNAL void duk_push_nan(duk_hthread *thr) {
	duk_tval *tv_slot;
	duk_double_union du;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	DUK_DBLUNION_SET_NAN(&du);
	DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_NUMBER(tv_slot, du.d);
}

DUK_EXTERNAL const char *duk_push_lstring(duk_hthread *thr, const char *str, duk_size_t len) {
	duk_hstring *h;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	/* Check stack before interning (avoid hanging temp). */
	DUK__CHECK_SPACE();

	/* NULL with zero length represents an empty string; NULL with higher
	 * length is also now treated like an empty string although it is
	 * a bit dubious.  This is unlike duk_push_string() which pushes a
	 * 'null' if the input string is a NULL.
	 */
	if (DUK_UNLIKELY(str == NULL)) {
		len = 0U;
	}

	/* Check for maximum string length. */
	if (DUK_UNLIKELY(len > DUK_HSTRING_MAX_BYTELEN)) {
		DUK_ERROR_RANGE(thr, DUK_STR_STRING_TOO_LONG);
		DUK_WO_NORETURN(return NULL;);
	}

	h = duk_heap_strtable_intern_checked(thr, (const duk_uint8_t *) str, (duk_uint32_t) len);
	DUK_ASSERT(h != NULL);

	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_STRING(tv_slot, h);
	DUK_HSTRING_INCREF(thr, h);  /* no side effects */

	return (const char *) DUK_HSTRING_GET_DATA(h);
}

DUK_EXTERNAL const char *duk_push_string(duk_hthread *thr, const char *str) {
	DUK_ASSERT_API_ENTRY(thr);

	if (str) {
		return duk_push_lstring(thr, str, DUK_STRLEN(str));
	} else {
		duk_push_null(thr);
		return NULL;
	}
}

#if !defined(DUK_USE_PREFER_SIZE)
#if defined(DUK_USE_LITCACHE_SIZE)
DUK_EXTERNAL const char *duk_push_literal_raw(duk_hthread *thr, const char *str, duk_size_t len) {
	duk_hstring *h;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(str != NULL);
	DUK_ASSERT(str[len] == (char) 0);

	/* Check for maximum string length. */
	if (DUK_UNLIKELY(len > DUK_HSTRING_MAX_BYTELEN)) {
		DUK_ERROR_RANGE(thr, DUK_STR_STRING_TOO_LONG);
		DUK_WO_NORETURN(return NULL;);
	}

	h = duk_heap_strtable_intern_literal_checked(thr, (const duk_uint8_t *) str, (duk_uint32_t) len);
	DUK_ASSERT(h != NULL);

	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_STRING(tv_slot, h);
	DUK_HSTRING_INCREF(thr, h);  /* no side effects */

	return (const char *) DUK_HSTRING_GET_DATA(h);
}
#else  /* DUK_USE_LITCACHE_SIZE */
DUK_EXTERNAL const char *duk_push_literal_raw(duk_hthread *thr, const char *str, duk_size_t len) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(str != NULL);
	DUK_ASSERT(str[len] == (char) 0);

	return duk_push_lstring(thr, str, len);
}
#endif  /* DUK_USE_LITCACHE_SIZE */
#endif  /* !DUK_USE_PREFER_SIZE */

DUK_EXTERNAL void duk_push_pointer(duk_hthread *thr, void *val) {
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK__CHECK_SPACE();
	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_POINTER(tv_slot, val);
}

DUK_INTERNAL duk_hstring *duk_push_uint_to_hstring(duk_hthread *thr, duk_uint_t i) {
	duk_hstring *h_tmp;

	DUK_ASSERT_API_ENTRY(thr);

	/* XXX: this could be a direct DUK_SPRINTF to a buffer followed by duk_push_string() */
	duk_push_uint(thr, (duk_uint_t) i);
	h_tmp = duk_to_hstring_m1(thr);
	DUK_ASSERT(h_tmp != NULL);
	return h_tmp;
}

DUK_LOCAL void duk__push_this_helper(duk_hthread *thr, duk_small_uint_t check_object_coercible) {
	duk_tval *tv_slot;

	DUK__CHECK_SPACE();

	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));  /* because of valstack init policy */
	tv_slot = thr->valstack_top++;

	if (DUK_UNLIKELY(thr->callstack_curr == NULL)) {
		if (check_object_coercible) {
			goto type_error;
		}
		/* 'undefined' already on stack top */
	} else {
		duk_tval *tv;

		/* 'this' binding is just before current activation's bottom */
		DUK_ASSERT(thr->valstack_bottom > thr->valstack);
		tv = thr->valstack_bottom - 1;
		if (check_object_coercible &&
		    (DUK_TVAL_IS_UNDEFINED(tv) || DUK_TVAL_IS_NULL(tv))) {
			/* XXX: better macro for DUK_TVAL_IS_UNDEFINED_OR_NULL(tv) */
			goto type_error;
		}

		DUK_TVAL_SET_TVAL(tv_slot, tv);
		DUK_TVAL_INCREF(thr, tv);
	}
	return;

 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_NOT_OBJECT_COERCIBLE);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_push_this(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk__push_this_helper(thr, 0 /*check_object_coercible*/);
}

DUK_INTERNAL void duk_push_this_check_object_coercible(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk__push_this_helper(thr, 1 /*check_object_coercible*/);
}

DUK_INTERNAL duk_hobject *duk_push_this_coercible_to_object(duk_hthread *thr) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	duk__push_this_helper(thr, 1 /*check_object_coercible*/);
	h = duk_to_hobject(thr, -1);
	DUK_ASSERT(h != NULL);
	return h;
}

DUK_INTERNAL duk_hstring *duk_push_this_coercible_to_string(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk__push_this_helper(thr, 1 /*check_object_coercible*/);
	return duk_to_hstring_m1(thr);  /* This will reject all Symbol values; accepts Symbol objects. */
}

DUK_INTERNAL duk_tval *duk_get_borrowed_this_tval(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_ASSERT(thr->callstack_top > 0);  /* caller required to know */
	DUK_ASSERT(thr->callstack_curr != NULL);  /* caller required to know */
	DUK_ASSERT(thr->valstack_bottom > thr->valstack);  /* consequence of above */
	DUK_ASSERT(thr->valstack_bottom - 1 >= thr->valstack);  /* 'this' binding exists */

	return thr->valstack_bottom - 1;
}

DUK_EXTERNAL void duk_push_new_target(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT_API_ENTRY(thr);

	/* https://www.ecma-international.org/ecma-262/6.0/#sec-meta-properties-runtime-semantics-evaluation
	 * https://www.ecma-international.org/ecma-262/6.0/#sec-getnewtarget
	 *
	 * No newTarget support now, so as a first approximation
	 * use the resolved (non-bound) target function.
	 *
	 * Check CONSTRUCT flag from current function, or if running
	 * direct eval, from a non-direct-eval parent (with possibly
	 * more than one nested direct eval).  An alternative to this
	 * would be to store [[NewTarget]] as a hidden symbol of the
	 * lexical scope, and then just look up that variable.
	 *
	 * Calls from the application will either be for an empty
	 * call stack, or a Duktape/C function as the top activation.
	 */

	act = thr->callstack_curr;
	for (;;) {
		if (act == NULL) {
			break;
		}

		if (act->flags & DUK_ACT_FLAG_CONSTRUCT) {
			duk_push_tval(thr, &act->tv_func);
			return;
		} else if (act->flags & DUK_ACT_FLAG_DIRECT_EVAL) {
			act = act->parent;
		} else {
			break;
		}
	}

	duk_push_undefined(thr);
}

DUK_EXTERNAL void duk_push_current_function(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT_API_ENTRY(thr);

	act = thr->callstack_curr;
	if (act != NULL) {
		duk_push_tval(thr, &act->tv_func);
	} else {
		duk_push_undefined(thr);
	}
}

DUK_EXTERNAL void duk_push_current_thread(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	if (thr->heap->curr_thread) {
		duk_push_hobject(thr, (duk_hobject *) thr->heap->curr_thread);
	} else {
		duk_push_undefined(thr);
	}
}

DUK_EXTERNAL void duk_push_global_object(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_push_hobject_bidx(thr, DUK_BIDX_GLOBAL);
}

/* XXX: size optimize */
DUK_LOCAL void duk__push_stash(duk_hthread *thr) {
	if (!duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE)) {
		DUK_DDD(DUK_DDDPRINT("creating heap/global/thread stash on first use"));
		duk_pop_unsafe(thr);
		duk_push_bare_object(thr);
		duk_dup_top(thr);
		duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_C);  /* [ ... parent stash stash ] -> [ ... parent stash ] */
	}
	duk_remove_m2(thr);
}

DUK_EXTERNAL void duk_push_heap_stash(duk_hthread *thr) {
	duk_heap *heap;
	DUK_ASSERT_API_ENTRY(thr);
	heap = thr->heap;
	DUK_ASSERT(heap->heap_object != NULL);
	duk_push_hobject(thr, heap->heap_object);
	duk__push_stash(thr);
}

DUK_EXTERNAL void duk_push_global_stash(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_push_global_object(thr);
	duk__push_stash(thr);
}

DUK_EXTERNAL void duk_push_thread_stash(duk_hthread *thr, duk_hthread *target_thr) {
	DUK_ASSERT_API_ENTRY(thr);
	if (DUK_UNLIKELY(target_thr == NULL)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return;);
	}
	duk_push_hobject(thr, (duk_hobject *) target_thr);
	duk__push_stash(thr);
}

/* XXX: duk_ssize_t would be useful here */
DUK_LOCAL duk_int_t duk__try_push_vsprintf(duk_hthread *thr, void *buf, duk_size_t sz, const char *fmt, va_list ap) {
	duk_int_t len;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_UNREF(thr);

	/* NUL terminator handling doesn't matter here */
	len = DUK_VSNPRINTF((char *) buf, sz, fmt, ap);
	if (len < (duk_int_t) sz) {
		/* Return value of 'sz' or more indicates output was (potentially)
		 * truncated.
		 */
		return (duk_int_t) len;
	}
	return -1;
}

DUK_EXTERNAL const char *duk_push_vsprintf(duk_hthread *thr, const char *fmt, va_list ap) {
	duk_uint8_t stack_buf[DUK_PUSH_SPRINTF_INITIAL_SIZE];
	duk_size_t sz = DUK_PUSH_SPRINTF_INITIAL_SIZE;
	duk_bool_t pushed_buf = 0;
	void *buf;
	duk_int_t len;  /* XXX: duk_ssize_t */
	const char *res;

	DUK_ASSERT_API_ENTRY(thr);

	/* special handling of fmt==NULL */
	if (!fmt) {
		duk_hstring *h_str;
		duk_push_hstring_empty(thr);
		h_str = duk_known_hstring(thr, -1);
		return (const char *) DUK_HSTRING_GET_DATA(h_str);
	}

	/* initial estimate based on format string */
	sz = DUK_STRLEN(fmt) + 16;  /* format plus something to avoid just missing */
	if (sz < DUK_PUSH_SPRINTF_INITIAL_SIZE) {
		sz = DUK_PUSH_SPRINTF_INITIAL_SIZE;
	}
	DUK_ASSERT(sz > 0);

	/* Try to make do with a stack buffer to avoid allocating a temporary buffer.
	 * This works 99% of the time which is quite nice.
	 */
	for (;;) {
		va_list ap_copy;  /* copied so that 'ap' can be reused */

		if (sz <= sizeof(stack_buf)) {
			buf = stack_buf;
		} else if (!pushed_buf) {
			pushed_buf = 1;
			buf = duk_push_dynamic_buffer(thr, sz);
		} else {
			buf = duk_resize_buffer(thr, -1, sz);
		}
		DUK_ASSERT(buf != NULL);

		DUK_VA_COPY(ap_copy, ap);
		len = duk__try_push_vsprintf(thr, buf, sz, fmt, ap_copy);
		va_end(ap_copy);
		if (len >= 0) {
			break;
		}

		/* failed, resize and try again */
		sz = sz * 2;
		if (DUK_UNLIKELY(sz >= DUK_PUSH_SPRINTF_SANITY_LIMIT)) {
			DUK_ERROR_RANGE(thr, DUK_STR_RESULT_TOO_LONG);
			DUK_WO_NORETURN(return NULL;);
		}
	}

	/* Cannot use duk_buffer_to_string() on the buffer because it is
	 * usually larger than 'len'; 'buf' is also usually a stack buffer.
	 */
	res = duk_push_lstring(thr, (const char *) buf, (duk_size_t) len);  /* [ buf? res ] */
	if (pushed_buf) {
		duk_remove_m2(thr);
	}
	return res;
}

DUK_EXTERNAL const char *duk_push_sprintf(duk_hthread *thr, const char *fmt, ...) {
	va_list ap;
	const char *ret;

	DUK_ASSERT_API_ENTRY(thr);

	/* allow fmt==NULL */
	va_start(ap, fmt);
	ret = duk_push_vsprintf(thr, fmt, ap);
	va_end(ap);

	return ret;
}

DUK_INTERNAL duk_hobject *duk_push_object_helper(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_small_int_t prototype_bidx) {
	duk_tval *tv_slot;
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(prototype_bidx == -1 ||
	           (prototype_bidx >= 0 && prototype_bidx < DUK_NUM_BUILTINS));

	DUK__CHECK_SPACE();

	h = duk_hobject_alloc(thr, hobject_flags_and_class);
	DUK_ASSERT(h != NULL);

	DUK_DDD(DUK_DDDPRINT("created object with flags: 0x%08lx", (unsigned long) h->hdr.h_flags));

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, h);
	DUK_HOBJECT_INCREF(thr, h);  /* no side effects */
	thr->valstack_top++;

	/* object is now reachable */

	if (prototype_bidx >= 0) {
		DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, h, thr->builtins[prototype_bidx]);
	} else {
		DUK_ASSERT(prototype_bidx == -1);
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h) == NULL);
	}

	return h;
}

DUK_INTERNAL duk_hobject *duk_push_object_helper_proto(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_hobject *proto) {
	duk_hobject *h;

	DUK_ASSERT_API_ENTRY(thr);

	h = duk_push_object_helper(thr, hobject_flags_and_class, -1);
	DUK_ASSERT(h != NULL);
	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, h, proto);
	return h;
}

DUK_EXTERNAL duk_idx_t duk_push_object(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                              DUK_BIDX_OBJECT_PROTOTYPE);
	return duk_get_top_index_unsafe(thr);
}

DUK_EXTERNAL duk_idx_t duk_push_array(duk_hthread *thr) {
	duk_uint_t flags;
	duk_harray *obj;
	duk_idx_t ret;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_ARRAY_PART |
	        DUK_HOBJECT_FLAG_EXOTIC_ARRAY |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARRAY);

	obj = duk_harray_alloc(thr, flags);
	DUK_ASSERT(obj != NULL);

	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) obj, thr->builtins[DUK_BIDX_ARRAY_PROTOTYPE]);

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);  /* XXX: could preallocate with refcount = 1 */
	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	thr->valstack_top++;

	DUK_ASSERT(obj->length == 0);  /* Array .length starts at zero. */
	return ret;
}

DUK_EXTERNAL duk_idx_t duk_push_bare_array(duk_hthread *thr) {
	duk_uint_t flags;
	duk_harray *obj;
	duk_idx_t ret;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_ARRAY_PART |
	        DUK_HOBJECT_FLAG_EXOTIC_ARRAY |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARRAY);

	obj = duk_harray_alloc(thr, flags);
	DUK_ASSERT(obj != NULL);

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);  /* XXX: could preallocate with refcount = 1 */
	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	thr->valstack_top++;

	DUK_ASSERT(obj->length == 0);  /* Array .length starts at zero. */
	return ret;
}

DUK_INTERNAL duk_harray *duk_push_harray(duk_hthread *thr) {
	/* XXX: API call could do this directly, cast to void in API macro. */
	duk_harray *a;

	DUK_ASSERT_API_ENTRY(thr);

	(void) duk_push_array(thr);
	DUK_ASSERT(DUK_TVAL_IS_OBJECT(thr->valstack_top - 1));
	a = (duk_harray *) DUK_TVAL_GET_OBJECT(thr->valstack_top - 1);
	DUK_ASSERT(a != NULL);
	return a;
}

/* Push a duk_harray with preallocated size (.length also set to match size).
 * Caller may then populate array part of the duk_harray directly.
 */
DUK_INTERNAL duk_harray *duk_push_harray_with_size(duk_hthread *thr, duk_uint32_t size) {
	duk_harray *a;

	DUK_ASSERT_API_ENTRY(thr);

	a = duk_push_harray(thr);

	duk_hobject_realloc_props(thr,
	                          (duk_hobject *) a,
	                          0,
	                          size,
	                          0,
	                          0);
	a->length = size;
	return a;
}

DUK_INTERNAL duk_tval *duk_push_harray_with_size_outptr(duk_hthread *thr, duk_uint32_t size) {
	duk_harray *a;

	DUK_ASSERT_API_ENTRY(thr);

	a = duk_push_harray_with_size(thr, size);
	DUK_ASSERT(a != NULL);
	return DUK_HOBJECT_A_GET_BASE(thr->heap, (duk_hobject *) a);
}

DUK_EXTERNAL duk_idx_t duk_push_thread_raw(duk_hthread *thr, duk_uint_t flags) {
	duk_hthread *obj;
	duk_idx_t ret;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();

	obj = duk_hthread_alloc(thr,
	                        DUK_HOBJECT_FLAG_EXTENSIBLE |
	                        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_THREAD));
	DUK_ASSERT(obj != NULL);
	obj->state = DUK_HTHREAD_STATE_INACTIVE;
#if defined(DUK_USE_ROM_STRINGS)
	/* Nothing to initialize, strs[] is in ROM. */
#else
#if defined(DUK_USE_HEAPPTR16)
	obj->strs16 = thr->strs16;
#else
	obj->strs = thr->strs;
#endif
#endif
	DUK_DDD(DUK_DDDPRINT("created thread object with flags: 0x%08lx", (unsigned long) obj->obj.hdr.h_flags));

	/* make the new thread reachable */
	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HTHREAD_INCREF(thr, obj);
	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	thr->valstack_top++;

	/* important to do this *after* pushing, to make the thread reachable for gc */
	if (DUK_UNLIKELY(!duk_hthread_init_stacks(thr->heap, obj))) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return 0;);
	}

	/* initialize built-ins - either by copying or creating new ones */
	if (flags & DUK_THREAD_NEW_GLOBAL_ENV) {
		duk_hthread_create_builtin_objects(obj);
	} else {
		duk_hthread_copy_builtin_objects(thr, obj);
	}

	/* default prototype */
	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) obj, obj->builtins[DUK_BIDX_THREAD_PROTOTYPE]);

	/* Initial stack size satisfies the stack slack constraints so there
	 * is no need to require stack here.
	 */
	DUK_ASSERT(DUK_VALSTACK_INITIAL_SIZE >=
	           DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);

	return ret;
}

DUK_INTERNAL duk_hcompfunc *duk_push_hcompfunc(duk_hthread *thr) {
	duk_hcompfunc *obj;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();

	/* Template functions are not strictly constructable (they don't
	 * have a "prototype" property for instance), so leave the
	 * DUK_HOBJECT_FLAG_CONSRUCTABLE flag cleared here.
	 */

	obj = duk_hcompfunc_alloc(thr,
	                          DUK_HOBJECT_FLAG_EXTENSIBLE |
	                          DUK_HOBJECT_FLAG_CALLABLE |
	                          DUK_HOBJECT_FLAG_COMPFUNC |
	                          DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION));
	if (DUK_UNLIKELY(obj == NULL)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}

	DUK_DDD(DUK_DDDPRINT("created compiled function object with flags: 0x%08lx", (unsigned long) obj->obj.hdr.h_flags));

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);
	thr->valstack_top++;

	/* default prototype */
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) obj) == NULL);
	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) obj, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);

	return obj;
}

DUK_INTERNAL duk_hboundfunc *duk_push_hboundfunc(duk_hthread *thr) {
	duk_hboundfunc *obj;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();
	obj = duk_hboundfunc_alloc(thr->heap,
	                           DUK_HOBJECT_FLAG_EXTENSIBLE |
	                           DUK_HOBJECT_FLAG_BOUNDFUNC |
	                           DUK_HOBJECT_FLAG_CONSTRUCTABLE |
	                           DUK_HOBJECT_FLAG_CALLABLE |
	                           DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION));
	if (!obj) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}

	tv_slot = thr->valstack_top++;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);

	/* Prototype is left as NULL because the caller always sets it (and
	 * it depends on the target function).
	 */
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) obj) == NULL);

	return obj;
}

DUK_LOCAL duk_idx_t duk__push_c_function_raw(duk_hthread *thr, duk_c_function func, duk_idx_t nargs, duk_uint_t flags, duk_small_uint_t proto_bidx) {
	duk_hnatfunc *obj;
	duk_idx_t ret;
	duk_tval *tv_slot;
	duk_int16_t func_nargs;

	DUK_CTX_ASSERT_VALID(thr);

	DUK__CHECK_SPACE();

	if (DUK_UNLIKELY(func == NULL)) {
		goto api_error;
	}
	if (nargs >= 0 && nargs < DUK_HNATFUNC_NARGS_MAX) {
		func_nargs = (duk_int16_t) nargs;
	} else if (nargs == DUK_VARARGS) {
		func_nargs = DUK_HNATFUNC_NARGS_VARARGS;
	} else {
		goto api_error;
	}

	obj = duk_hnatfunc_alloc(thr, flags);
	DUK_ASSERT(obj != NULL);

	obj->func = func;
	obj->nargs = func_nargs;

	DUK_DDD(DUK_DDDPRINT("created native function object with flags: 0x%08lx, nargs=%ld",
	                     (unsigned long) obj->obj.hdr.h_flags, (long) obj->nargs));

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);
	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	thr->valstack_top++;

	DUK_ASSERT_BIDX_VALID(proto_bidx);
	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) obj, thr->builtins[proto_bidx]);
	return ret;

 api_error:
	DUK_ERROR_TYPE_INVALID_ARGS(thr);
	DUK_WO_NORETURN(return 0;);
}

DUK_EXTERNAL duk_idx_t duk_push_c_function(duk_hthread *thr, duk_c_function func, duk_int_t nargs) {
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_CONSTRUCTABLE |
	        DUK_HOBJECT_FLAG_CALLABLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_NATFUNC |
	        DUK_HOBJECT_FLAG_NEWENV |
	        DUK_HOBJECT_FLAG_STRICT |
	        DUK_HOBJECT_FLAG_NOTAIL |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION);

	/* Default prototype is a Duktape specific %NativeFunctionPrototype%
	 * which provides .length and .name getters.
	 */
	return duk__push_c_function_raw(thr, func, nargs, flags, DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE);
}

DUK_INTERNAL void duk_push_c_function_builtin(duk_hthread *thr, duk_c_function func, duk_int_t nargs) {
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_CONSTRUCTABLE |
	        DUK_HOBJECT_FLAG_CALLABLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_NATFUNC |
	        DUK_HOBJECT_FLAG_NEWENV |
	        DUK_HOBJECT_FLAG_STRICT |
	        DUK_HOBJECT_FLAG_NOTAIL |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION);

	/* Must use Function.prototype for standard built-in functions. */
	(void) duk__push_c_function_raw(thr, func, nargs, flags, DUK_BIDX_FUNCTION_PROTOTYPE);
}

DUK_INTERNAL void duk_push_c_function_builtin_noconstruct(duk_hthread *thr, duk_c_function func, duk_int_t nargs) {
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);

	flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
	        DUK_HOBJECT_FLAG_CALLABLE |
	        DUK_HOBJECT_FLAG_FASTREFS |
	        DUK_HOBJECT_FLAG_NATFUNC |
	        DUK_HOBJECT_FLAG_NEWENV |
	        DUK_HOBJECT_FLAG_STRICT |
	        DUK_HOBJECT_FLAG_NOTAIL |
	        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION);

	/* Must use Function.prototype for standard built-in functions. */
	(void) duk__push_c_function_raw(thr, func, nargs, flags, DUK_BIDX_FUNCTION_PROTOTYPE);
}

DUK_EXTERNAL duk_idx_t duk_push_c_lightfunc(duk_hthread *thr, duk_c_function func, duk_idx_t nargs, duk_idx_t length, duk_int_t magic) {
	duk_small_uint_t lf_flags;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();

	if (nargs >= DUK_LFUNC_NARGS_MIN && nargs <= DUK_LFUNC_NARGS_MAX) {
		/* as is */
	} else if (nargs == DUK_VARARGS) {
		nargs = DUK_LFUNC_NARGS_VARARGS;
	} else {
		goto api_error;
	}
	if (DUK_UNLIKELY(!(length >= DUK_LFUNC_LENGTH_MIN && length <= DUK_LFUNC_LENGTH_MAX))) {
		goto api_error;
	}
	if (DUK_UNLIKELY(!(magic >= DUK_LFUNC_MAGIC_MIN && magic <= DUK_LFUNC_MAGIC_MAX))) {
		goto api_error;
	}

	lf_flags = DUK_LFUNC_FLAGS_PACK((duk_small_int_t) magic, (duk_small_uint_t) length, (duk_small_uint_t) nargs);
	tv_slot = thr->valstack_top++;
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv_slot));
	DUK_TVAL_SET_LIGHTFUNC(tv_slot, func, lf_flags);
	DUK_ASSERT(tv_slot >= thr->valstack_bottom);
	return (duk_idx_t) (tv_slot - thr->valstack_bottom);

 api_error:
	DUK_ERROR_TYPE_INVALID_ARGS(thr);
	DUK_WO_NORETURN(return 0;);
}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_hbufobj *duk_push_bufobj_raw(duk_hthread *thr, duk_uint_t hobject_flags_and_class, duk_small_int_t prototype_bidx) {
	duk_hbufobj *obj;
	duk_tval *tv_slot;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(prototype_bidx >= 0);

	DUK__CHECK_SPACE();

	obj = duk_hbufobj_alloc(thr, hobject_flags_and_class);
	DUK_ASSERT(obj != NULL);

	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) obj, thr->builtins[prototype_bidx]);
	DUK_HBUFOBJ_ASSERT_VALID(obj);

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) obj);
	DUK_HOBJECT_INCREF(thr, obj);
	thr->valstack_top++;

	return obj;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/* XXX: There's quite a bit of overlap with buffer creation handling in
 * duk_bi_buffer.c.  Look for overlap and refactor.
 */
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#define DUK__PACK_ARGS(classnum,protobidx,elemtype,elemshift,istypedarray) \
	(((classnum) << 24) | ((protobidx) << 16) | ((elemtype) << 8) | ((elemshift) << 4) | (istypedarray))

static const duk_uint32_t duk__bufobj_flags_lookup[] = {
	/* Node.js Buffers are Uint8Array instances which inherit from Buffer.prototype. */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_ARRAYBUFFER,       DUK_BIDX_ARRAYBUFFER_PROTOTYPE,       DUK_HBUFOBJ_ELEM_UINT8,        0, 0),  /* DUK_BUFOBJ_ARRAYBUFFER */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_UINT8ARRAY,        DUK_BIDX_NODEJS_BUFFER_PROTOTYPE,     DUK_HBUFOBJ_ELEM_UINT8,        0, 1),  /* DUK_BUFOBJ_NODEJS_BUFFER */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_DATAVIEW,          DUK_BIDX_DATAVIEW_PROTOTYPE,          DUK_HBUFOBJ_ELEM_UINT8,        0, 0),  /* DUK_BUFOBJ_DATAVIEW */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_INT8ARRAY,         DUK_BIDX_INT8ARRAY_PROTOTYPE,         DUK_HBUFOBJ_ELEM_INT8,         0, 1),  /* DUK_BUFOBJ_INT8ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_UINT8ARRAY,        DUK_BIDX_UINT8ARRAY_PROTOTYPE,        DUK_HBUFOBJ_ELEM_UINT8,        0, 1),  /* DUK_BUFOBJ_UINT8ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_UINT8CLAMPEDARRAY, DUK_BIDX_UINT8CLAMPEDARRAY_PROTOTYPE, DUK_HBUFOBJ_ELEM_UINT8CLAMPED, 0, 1),  /* DUK_BUFOBJ_UINT8CLAMPEDARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_INT16ARRAY,        DUK_BIDX_INT16ARRAY_PROTOTYPE,        DUK_HBUFOBJ_ELEM_INT16,        1, 1),  /* DUK_BUFOBJ_INT16ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_UINT16ARRAY,       DUK_BIDX_UINT16ARRAY_PROTOTYPE,       DUK_HBUFOBJ_ELEM_UINT16,       1, 1),  /* DUK_BUFOBJ_UINT16ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_INT32ARRAY,        DUK_BIDX_INT32ARRAY_PROTOTYPE,        DUK_HBUFOBJ_ELEM_INT32,        2, 1),  /* DUK_BUFOBJ_INT32ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_UINT32ARRAY,       DUK_BIDX_UINT32ARRAY_PROTOTYPE,       DUK_HBUFOBJ_ELEM_UINT32,       2, 1),  /* DUK_BUFOBJ_UINT32ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_FLOAT32ARRAY,      DUK_BIDX_FLOAT32ARRAY_PROTOTYPE,      DUK_HBUFOBJ_ELEM_FLOAT32,      2, 1),  /* DUK_BUFOBJ_FLOAT32ARRAY */
	DUK__PACK_ARGS(DUK_HOBJECT_CLASS_FLOAT64ARRAY,      DUK_BIDX_FLOAT64ARRAY_PROTOTYPE,      DUK_HBUFOBJ_ELEM_FLOAT64,      3, 1)   /* DUK_BUFOBJ_FLOAT64ARRAY */
};
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_EXTERNAL void duk_push_buffer_object(duk_hthread *thr, duk_idx_t idx_buffer, duk_size_t byte_offset, duk_size_t byte_length, duk_uint_t flags) {
	duk_hbufobj *h_bufobj;
	duk_hbuffer *h_val;
	duk_hobject *h_arraybuf;
	duk_uint32_t tmp;
	duk_uint_t classnum;
	duk_uint_t protobidx;
	duk_uint_t lookupidx;
	duk_uint_t uint_offset, uint_length, uint_added;

	DUK_ASSERT_API_ENTRY(thr);

	/* The underlying types for offset/length in duk_hbufobj is
	 * duk_uint_t; make sure argument values fit.
	 */
	uint_offset = (duk_uint_t) byte_offset;
	uint_length = (duk_uint_t) byte_length;
	if (sizeof(duk_size_t) != sizeof(duk_uint_t)) {
		if (DUK_UNLIKELY((duk_size_t) uint_offset != byte_offset || (duk_size_t) uint_length != byte_length)) {
			goto range_error;
		}
	}

	DUK_ASSERT_DISABLE(flags >= 0);  /* flags is unsigned */
	lookupidx = flags;
	if (DUK_UNLIKELY(lookupidx >= sizeof(duk__bufobj_flags_lookup) / sizeof(duk_uint32_t))) {
		goto arg_error;
	}
	tmp = duk__bufobj_flags_lookup[lookupidx];
	classnum = tmp >> 24;
	protobidx = (tmp >> 16) & 0xff;

	h_arraybuf = duk_get_hobject(thr, idx_buffer);
	if (h_arraybuf != NULL &&  /* argument is an object */
	    flags != DUK_BUFOBJ_ARRAYBUFFER &&  /* creating a view */
	    DUK_HOBJECT_GET_CLASS_NUMBER(h_arraybuf) == DUK_HOBJECT_CLASS_ARRAYBUFFER  /* argument is ArrayBuffer */) {
		duk_uint_t tmp_offset;

		DUK_HBUFOBJ_ASSERT_VALID((duk_hbufobj *) h_arraybuf);
		h_val = ((duk_hbufobj *) h_arraybuf)->buf;
		if (DUK_UNLIKELY(h_val == NULL)) {
			goto arg_error;
		}

		tmp_offset = uint_offset + ((duk_hbufobj *) h_arraybuf)->offset;
		if (DUK_UNLIKELY(tmp_offset < uint_offset)) {
			goto range_error;
		}
		uint_offset = tmp_offset;

		/* Note intentional difference to new TypedArray(): we allow
		 * caller to create an uncovered typed array (which is memory
		 * safe); new TypedArray() rejects it.
		 */
	} else {
		/* Handle unexpected object arguments here too, for nice error
		 * messages.
		 */
		h_arraybuf = NULL;
		h_val = duk_require_hbuffer(thr, idx_buffer);
	}

	/* Wrap check for offset+length. */
	uint_added = uint_offset + uint_length;
	if (DUK_UNLIKELY(uint_added < uint_offset)) {
		goto range_error;
	}
	DUK_ASSERT(uint_added >= uint_offset && uint_added >= uint_length);

	DUK_ASSERT(h_val != NULL);

	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(classnum),
	                               (duk_small_int_t) protobidx);
	DUK_ASSERT(h_bufobj != NULL);

	h_bufobj->buf = h_val;
	DUK_HBUFFER_INCREF(thr, h_val);
	h_bufobj->buf_prop = h_arraybuf;
	DUK_HOBJECT_INCREF_ALLOWNULL(thr, h_arraybuf);
	h_bufobj->offset = uint_offset;
	h_bufobj->length = uint_length;
	h_bufobj->shift = (tmp >> 4) & 0x0f;
	h_bufobj->elem_type = (tmp >> 8) & 0xff;
	h_bufobj->is_typedarray = tmp & 0x0f;
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

	/* TypedArray views need an automatic ArrayBuffer which must be
	 * provided as .buffer property of the view.  The ArrayBuffer is
	 * referenced via duk_hbufobj->buf_prop and an inherited .buffer
	 * accessor returns it.  The ArrayBuffer is created lazily on first
	 * access if necessary so we don't need to do anything more here.
	 */
	return;

 range_error:
	DUK_ERROR_RANGE(thr, DUK_STR_INVALID_ARGS);
	DUK_WO_NORETURN(return;);

 arg_error:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_ARGS);
	DUK_WO_NORETURN(return;);
}
#else  /* DUK_USE_BUFFEROBJECT_SUPPORT */
DUK_EXTERNAL void duk_push_buffer_object(duk_hthread *thr, duk_idx_t idx_buffer, duk_size_t byte_offset, duk_size_t byte_length, duk_uint_t flags) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(idx_buffer);
	DUK_UNREF(byte_offset);
	DUK_UNREF(byte_length);
	DUK_UNREF(flags);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

DUK_EXTERNAL duk_idx_t duk_push_error_object_va_raw(duk_hthread *thr, duk_errcode_t err_code, const char *filename, duk_int_t line, const char *fmt, va_list ap) {
	duk_hobject *proto;
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
	duk_small_uint_t augment_flags;
#endif

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr != NULL);
	DUK_UNREF(filename);
	DUK_UNREF(line);

	/* Error code also packs a tracedata related flag. */
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
	augment_flags = 0;
	if (err_code & DUK_ERRCODE_FLAG_NOBLAME_FILELINE) {
		augment_flags = DUK_AUGMENT_FLAG_NOBLAME_FILELINE;
	}
#endif
	err_code = err_code & (~DUK_ERRCODE_FLAG_NOBLAME_FILELINE);

	/* error gets its 'name' from the prototype */
	proto = duk_error_prototype_from_code(thr, err_code);
	(void) duk_push_object_helper_proto(thr,
	                                    DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                    DUK_HOBJECT_FLAG_FASTREFS |
	                                    DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ERROR),
	                                    proto);

	/* ... and its 'message' from an instance property */
	if (fmt) {
		duk_push_vsprintf(thr, fmt, ap);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE, DUK_PROPDESC_FLAGS_WC);
	} else {
		/* If no explicit message given, put error code into message field
		 * (as a number).  This is not fully in keeping with the ECMAScript
		 * error model because messages are supposed to be strings (Error
		 * constructors use ToString() on their argument).  However, it's
		 * probably more useful than having a separate 'code' property.
		 */
		duk_push_int(thr, err_code);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE, DUK_PROPDESC_FLAGS_WC);
	}

	/* XXX: .code = err_code disabled, not sure if useful */

	/* Creation time error augmentation */
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
	/* filename may be NULL in which case file/line is not recorded */
	duk_err_augment_error_create(thr, thr, filename, line, augment_flags);  /* may throw an error */
#endif

	return duk_get_top_index_unsafe(thr);
}

DUK_EXTERNAL duk_idx_t duk_push_error_object_raw(duk_hthread *thr, duk_errcode_t err_code, const char *filename, duk_int_t line, const char *fmt, ...) {
	va_list ap;
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	va_start(ap, fmt);
	ret = duk_push_error_object_va_raw(thr, err_code, filename, line, fmt, ap);
	va_end(ap);
	return ret;
}

#if !defined(DUK_USE_VARIADIC_MACROS)
DUK_EXTERNAL duk_idx_t duk_push_error_object_stash(duk_hthread *thr, duk_errcode_t err_code, const char *fmt, ...) {
	const char *filename = duk_api_global_filename;
	duk_int_t line = duk_api_global_line;
	va_list ap;
	duk_idx_t ret;

	DUK_ASSERT_API_ENTRY(thr);

	duk_api_global_filename = NULL;
	duk_api_global_line = 0;
	va_start(ap, fmt);
	ret = duk_push_error_object_va_raw(thr, err_code, filename, line, fmt, ap);
	va_end(ap);
	return ret;
}
#endif  /* DUK_USE_VARIADIC_MACROS */

DUK_EXTERNAL void *duk_push_buffer_raw(duk_hthread *thr, duk_size_t size, duk_small_uint_t flags) {
	duk_tval *tv_slot;
	duk_hbuffer *h;
	void *buf_data;

	DUK_ASSERT_API_ENTRY(thr);

	DUK__CHECK_SPACE();

	/* Check for maximum buffer length. */
	if (DUK_UNLIKELY(size > DUK_HBUFFER_MAX_BYTELEN)) {
		DUK_ERROR_RANGE(thr, DUK_STR_BUFFER_TOO_LONG);
		DUK_WO_NORETURN(return NULL;);
	}

	h = duk_hbuffer_alloc(thr->heap, size, flags, &buf_data);
	if (DUK_UNLIKELY(h == NULL)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}

	tv_slot = thr->valstack_top;
	DUK_TVAL_SET_BUFFER(tv_slot, h);
	DUK_HBUFFER_INCREF(thr, h);
	thr->valstack_top++;

	return (void *) buf_data;
}

DUK_INTERNAL void *duk_push_fixed_buffer_nozero(duk_hthread *thr, duk_size_t len) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_push_buffer_raw(thr, len, DUK_BUF_FLAG_NOZERO);
}

DUK_INTERNAL void *duk_push_fixed_buffer_zero(duk_hthread *thr, duk_size_t len) {
	void *ptr;

	DUK_ASSERT_API_ENTRY(thr);

	ptr = duk_push_buffer_raw(thr, len, 0);
	DUK_ASSERT(ptr != NULL);
#if !defined(DUK_USE_ZERO_BUFFER_DATA)
	/* ES2015 requires zeroing even when DUK_USE_ZERO_BUFFER_DATA
	 * is not set.
	 */
	duk_memzero((void *) ptr, (size_t) len);
#endif
	return ptr;
}

#if defined(DUK_USE_ES6_PROXY)
DUK_EXTERNAL duk_idx_t duk_push_proxy(duk_hthread *thr, duk_uint_t proxy_flags) {
	duk_hobject *h_target;
	duk_hobject *h_handler;
	duk_hproxy *h_proxy;
	duk_tval *tv_slot;
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(proxy_flags);

	/* DUK__CHECK_SPACE() unnecessary because the Proxy is written to
	 * value stack in-place.
	 */
#if 0
	DUK__CHECK_SPACE();
#endif

	/* Reject a proxy object as the target because it would need
	 * special handling in property lookups.  (ES2015 has no such
	 * restriction.)
	 */
	h_target = duk_require_hobject_promote_mask(thr, -2, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	DUK_ASSERT(h_target != NULL);
	if (DUK_HOBJECT_IS_PROXY(h_target)) {
		goto fail_args;
	}

	/* Reject a proxy object as the handler because it would cause
	 * potentially unbounded recursion.  (ES2015 has no such
	 * restriction.)
	 *
	 * There's little practical reason to use a lightfunc or a plain
	 * buffer as the handler table: one could only provide traps via
	 * their prototype objects (Function.prototype and ArrayBuffer.prototype).
	 * Even so, as lightfuncs and plain buffers mimic their object
	 * counterparts, they're promoted and accepted here.
	 */
	h_handler = duk_require_hobject_promote_mask(thr, -1, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	DUK_ASSERT(h_handler != NULL);
	if (DUK_HOBJECT_IS_PROXY(h_handler)) {
		goto fail_args;
	}

	/* XXX: Proxy object currently has no prototype, so ToPrimitive()
	 * coercion fails which is a bit confusing.
	 */

	/* CALLABLE and CONSTRUCTABLE flags are copied from the (initial)
	 * target, see ES2015 Sections 9.5.15 and 9.5.13.
	 */
	flags = DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) h_target) &
	        (DUK_HOBJECT_FLAG_CALLABLE | DUK_HOBJECT_FLAG_CONSTRUCTABLE);
	flags |= DUK_HOBJECT_FLAG_EXTENSIBLE |
	         DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ;
	if (flags & DUK_HOBJECT_FLAG_CALLABLE) {
		flags |= DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION) |
		         DUK_HOBJECT_FLAG_SPECIAL_CALL;
	} else {
		flags |= DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT);
	}

	h_proxy = duk_hproxy_alloc(thr, flags);
	DUK_ASSERT(h_proxy != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_proxy) == NULL);

	/* Initialize Proxy target and handler references; avoid INCREF
	 * by stealing the value stack refcounts via direct value stack
	 * manipulation.  INCREF is needed for the Proxy itself however.
	 */
	DUK_ASSERT(h_target != NULL);
	h_proxy->target = h_target;
	DUK_ASSERT(h_handler != NULL);
	h_proxy->handler = h_handler;
	DUK_HPROXY_ASSERT_VALID(h_proxy);

	DUK_ASSERT(duk_get_hobject(thr, -2) == h_target);
	DUK_ASSERT(duk_get_hobject(thr, -1) == h_handler);
	tv_slot = thr->valstack_top - 2;
	DUK_ASSERT(tv_slot >= thr->valstack_bottom);
	DUK_TVAL_SET_OBJECT(tv_slot, (duk_hobject *) h_proxy);
	DUK_HOBJECT_INCREF(thr, (duk_hobject *) h_proxy);
	tv_slot++;
	DUK_TVAL_SET_UNDEFINED(tv_slot);  /* [ ... target handler ] -> [ ... proxy undefined ] */
	thr->valstack_top = tv_slot;      /* -> [ ... proxy ] */

	DUK_DD(DUK_DDPRINT("created Proxy: %!iT", duk_get_tval(thr, -1)));

	return (duk_idx_t) (thr->valstack_top - thr->valstack_bottom - 1);

 fail_args:
	DUK_ERROR_TYPE_INVALID_ARGS(thr);
	DUK_WO_NORETURN(return 0;);
}
#else  /* DUK_USE_ES6_PROXY */
DUK_EXTERNAL duk_idx_t duk_push_proxy(duk_hthread *thr, duk_uint_t proxy_flags) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(proxy_flags);
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return 0;);
}
#endif  /* DUK_USE_ES6_PROXY */

#if defined(DUK_USE_ASSERTIONS)
DUK_LOCAL void duk__validate_push_heapptr(duk_hthread *thr, void *ptr) {
	duk_heaphdr *h;
	duk_heaphdr *curr;
	duk_bool_t found = 0;

	h = (duk_heaphdr *) ptr;
	if (h == NULL) {
		/* Allowed. */
		return;
	}
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));

	/* One particular problem case is where an object has been
	 * queued for finalization but the finalizer hasn't yet been
	 * executed.
	 *
	 * Corner case: we're running in a finalizer for object X, and
	 * user code calls duk_push_heapptr() for X itself.  In this
	 * case X will be in finalize_list, and we can detect the case
	 * by seeing that X's FINALIZED flag is set (which is done before
	 * the finalizer starts executing).
	 */
#if defined(DUK_USE_FINALIZER_SUPPORT)
	for (curr = thr->heap->finalize_list;
	     curr != NULL;
	     curr = DUK_HEAPHDR_GET_NEXT(thr->heap, curr)) {
		/* FINALIZABLE is set for all objects on finalize_list
		 * except for an object being finalized right now.  So
		 * can't assert here.
		 */
#if 0
		DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZABLE(curr));
#endif

		if (curr == h) {
			if (DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) h)) {
				/* Object is currently being finalized. */
				DUK_ASSERT(found == 0);  /* Would indicate corrupted lists. */
				found = 1;
			} else {
				/* Not being finalized but on finalize_list,
				 * allowed since Duktape 2.1.
				 */
				DUK_ASSERT(found == 0);  /* Would indicate corrupted lists. */
				found = 1;
			}
		}
	}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

#if defined(DUK_USE_REFERENCE_COUNTING)
	/* Because refzero_list is now processed to completion inline with
	 * no side effects, it's always empty here.
	 */
	DUK_ASSERT(thr->heap->refzero_list == NULL);
#endif

	/* If not present in finalize_list (or refzero_list), it
	 * must be either in heap_allocated or the string table.
	 */
	if (DUK_HEAPHDR_IS_STRING(h)) {
		duk_uint32_t i;
		duk_hstring *str;
		duk_heap *heap = thr->heap;

		DUK_ASSERT(found == 0);
		for (i = 0; i < heap->st_size; i++) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
			str = DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, heap->strtable16[i]);
#else
			str = heap->strtable[i];
#endif
			while (str != NULL) {
				if (str == (duk_hstring *) h) {
					DUK_ASSERT(found == 0);  /* Would indicate corrupted lists. */
					found = 1;
					break;
				}
				str = str->hdr.h_next;
			}
		}
		DUK_ASSERT(found != 0);
	} else {
		for (curr = thr->heap->heap_allocated;
		     curr != NULL;
		     curr = DUK_HEAPHDR_GET_NEXT(thr->heap, curr)) {
			if (curr == h) {
				DUK_ASSERT(found == 0);  /* Would indicate corrupted lists. */
				found = 1;
			}
		}
		DUK_ASSERT(found != 0);
	}
}
#endif  /* DUK_USE_ASSERTIONS */

DUK_EXTERNAL duk_idx_t duk_push_heapptr(duk_hthread *thr, void *ptr) {
	duk_idx_t ret;
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	/* Reviving an object using a heap pointer is a dangerous API
	 * operation: if the application doesn't guarantee that the
	 * pointer target is always reachable, difficult-to-diagnose
	 * problems may ensue.  Try to validate the 'ptr' argument to
	 * the extent possible.
	 */

#if defined(DUK_USE_ASSERTIONS)
	duk__validate_push_heapptr(thr, ptr);
#endif

	DUK__CHECK_SPACE();

	ret = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	tv = thr->valstack_top++;

	if (ptr == NULL) {
		DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv));
		return ret;
	}

	DUK_HEAPHDR_ASSERT_VALID((duk_heaphdr *) ptr);

	/* If the argument is on finalize_list it has technically been
	 * unreachable before duk_push_heapptr() but it's still safe to
	 * push it.  Starting from Duktape 2.1 allow application code to
	 * do so.  There are two main cases:
	 *
	 *   (1) The object is on the finalize_list and we're called by
	 *       the finalizer for the object being finalized.  In this
	 *       case do nothing: finalize_list handling will deal with
	 *       the object queueing.  This is detected by the object not
	 *       having a FINALIZABLE flag despite being on the finalize_list;
	 *       the flag is cleared for the object being finalized only.
	 *
	 *   (2) The object is on the finalize_list but is not currently
	 *       being processed.  In this case the object can be queued
	 *       back to heap_allocated with a few flags cleared, in effect
	 *       cancelling the finalizer.
	 */
	if (DUK_UNLIKELY(DUK_HEAPHDR_HAS_FINALIZABLE((duk_heaphdr *) ptr))) {
		duk_heaphdr *curr;

		DUK_D(DUK_DPRINT("duk_push_heapptr() with a pointer on finalize_list, autorescue"));

		curr = (duk_heaphdr *) ptr;
		DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);

		/* Because FINALIZED is set prior to finalizer call, it will
		 * be set for the object being currently finalized, but not
		 * for other objects on finalize_list.
		 */
		DUK_HEAPHDR_CLEAR_FINALIZED(curr);

		/* Dequeue object from finalize_list and queue it back to
		 * heap_allocated.
		 */
#if defined(DUK_USE_REFERENCE_COUNTING)
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) >= 1);  /* Preincremented on finalize_list insert. */
		DUK_HEAPHDR_PREDEC_REFCOUNT(curr);
#endif
		DUK_HEAP_REMOVE_FROM_FINALIZE_LIST(thr->heap, curr);
		DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(thr->heap, curr);

		/* Continue with the rest. */
	}

	switch (DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) ptr)) {
	case DUK_HTYPE_STRING:
		DUK_TVAL_SET_STRING(tv, (duk_hstring *) ptr);
		break;
	case DUK_HTYPE_OBJECT:
		DUK_TVAL_SET_OBJECT(tv, (duk_hobject *) ptr);
		break;
	default:
		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) ptr) == DUK_HTYPE_BUFFER);
		DUK_TVAL_SET_BUFFER(tv, (duk_hbuffer *) ptr);
		break;
	}

	DUK_HEAPHDR_INCREF(thr, (duk_heaphdr *) ptr);

	return ret;
}

/* Push object with no prototype, i.e. a "bare" object. */
DUK_EXTERNAL duk_idx_t duk_push_bare_object(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                              -1);  /* no prototype */
	return duk_get_top_index_unsafe(thr);
}

DUK_INTERNAL void duk_push_hstring(duk_hthread *thr, duk_hstring *h) {
	duk_tval tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(h != NULL);

	DUK_TVAL_SET_STRING(&tv, h);
	duk_push_tval(thr, &tv);
}

DUK_INTERNAL void duk_push_hstring_stridx(duk_hthread *thr, duk_small_uint_t stridx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT_STRIDX_VALID(stridx);
	duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
}

DUK_INTERNAL void duk_push_hstring_empty(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_push_hstring(thr, DUK_HTHREAD_GET_STRING(thr, DUK_STRIDX_EMPTY_STRING));
}

DUK_INTERNAL void duk_push_hobject(duk_hthread *thr, duk_hobject *h) {
	duk_tval tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(h != NULL);

	DUK_TVAL_SET_OBJECT(&tv, h);
	duk_push_tval(thr, &tv);
}

DUK_INTERNAL void duk_push_hbuffer(duk_hthread *thr, duk_hbuffer *h) {
	duk_tval tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(h != NULL);

	DUK_TVAL_SET_BUFFER(&tv, h);
	duk_push_tval(thr, &tv);
}

DUK_INTERNAL void duk_push_hobject_bidx(duk_hthread *thr, duk_small_int_t builtin_idx) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(builtin_idx >= 0 && builtin_idx < DUK_NUM_BUILTINS);
	DUK_ASSERT(thr->builtins[builtin_idx] != NULL);

	duk_push_hobject(thr, thr->builtins[builtin_idx]);
}

/*
 *  Poppers
 */

DUK_LOCAL DUK_ALWAYS_INLINE void duk__pop_n_unsafe_raw(duk_hthread *thr, duk_idx_t count) {
	duk_tval *tv;
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_tval *tv_end;
#endif

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(count >= 0);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) count);

#if defined(DUK_USE_REFERENCE_COUNTING)
	tv = thr->valstack_top;
	tv_end = tv - count;
	while (tv != tv_end) {
		tv--;
		DUK_ASSERT(tv >= thr->valstack_bottom);
		DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, tv);
	}
	thr->valstack_top = tv;
	DUK_REFZERO_CHECK_FAST(thr);
#else
	tv = thr->valstack_top;
	while (count > 0) {
		count--;
		tv--;
		DUK_ASSERT(tv >= thr->valstack_bottom);
		DUK_TVAL_SET_UNDEFINED(tv);
	}
	thr->valstack_top = tv;
#endif

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}

DUK_EXTERNAL void duk_pop_n(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);

	if (DUK_UNLIKELY((duk_uidx_t) (thr->valstack_top - thr->valstack_bottom) < (duk_uidx_t) count)) {
		DUK_ERROR_RANGE_INVALID_COUNT(thr);
		DUK_WO_NORETURN(return;);
	}
	DUK_ASSERT(count >= 0);

	duk__pop_n_unsafe_raw(thr, count);
}

#if defined(DUK_USE_PREFER_SIZE)
DUK_INTERNAL void duk_pop_n_unsafe(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n(thr, count);
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_INTERNAL void duk_pop_n_unsafe(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);
	duk__pop_n_unsafe_raw(thr, count);
}
#endif  /* DUK_USE_PREFER_SIZE */

/* Pop N elements without DECREF (in effect "stealing" any actual refcounts). */
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_INTERNAL void duk_pop_n_nodecref_unsafe(duk_hthread *thr, duk_idx_t count) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(count >= 0);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) count);

	tv = thr->valstack_top;
	while (count > 0) {
		count--;
		tv--;
		DUK_ASSERT(tv >= thr->valstack_bottom);
		DUK_TVAL_SET_UNDEFINED(tv);
	}
	thr->valstack_top = tv;

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
#else  /* DUK_USE_REFERENCE_COUNTING */
DUK_INTERNAL void duk_pop_n_nodecref_unsafe(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_unsafe(thr, count);
}
#endif  /* DUK_USE_REFERENCE_COUNTING */

/* Popping one element is called so often that when footprint is not an issue,
 * compile a specialized function for it.
 */
#if defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL void duk_pop(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n(thr, 1);
}
DUK_INTERNAL void duk_pop_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_unsafe(thr, 1);
}
DUK_INTERNAL void duk_pop_nodecref_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_nodecref_unsafe(thr, 1);
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_LOCAL DUK_ALWAYS_INLINE void duk__pop_unsafe_raw(duk_hthread *thr) {
	duk_tval *tv;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(thr->valstack_top != thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) 1);

	tv = --thr->valstack_top;
	DUK_ASSERT(tv >= thr->valstack_bottom);
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv);  /* side effects */
#else
	DUK_TVAL_SET_UNDEFINED(tv);
#endif

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
DUK_EXTERNAL void duk_pop(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	if (DUK_UNLIKELY(thr->valstack_top == thr->valstack_bottom)) {
		DUK_ERROR_RANGE_INVALID_COUNT(thr);
		DUK_WO_NORETURN(return;);
	}

	duk__pop_unsafe_raw(thr);
}
DUK_INTERNAL void duk_pop_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk__pop_unsafe_raw(thr);
}
DUK_INTERNAL void duk_pop_nodecref_unsafe(duk_hthread *thr) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_top != thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) 1);

	tv = --thr->valstack_top;
	DUK_ASSERT(tv >= thr->valstack_bottom);
	DUK_TVAL_SET_UNDEFINED(tv);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
#endif  /* !DUK_USE_PREFER_SIZE */

#if defined(DUK_USE_PREFER_SIZE)
DUK_INTERNAL void duk_pop_undefined(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_nodecref_unsafe(thr);
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_INTERNAL void duk_pop_undefined(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_top != thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) 1);

	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top - 1));
	thr->valstack_top--;

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
#endif  /* !DUK_USE_PREFER_SIZE */

#if defined(DUK_USE_PREFER_SIZE)
DUK_EXTERNAL void duk_pop_2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n(thr, 2);
}
DUK_INTERNAL void duk_pop_2_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_unsafe(thr, 2);
}
DUK_INTERNAL void duk_pop_2_nodecref_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_nodecref_unsafe(thr, 2);
}
#else
DUK_LOCAL DUK_ALWAYS_INLINE void duk__pop_2_unsafe_raw(duk_hthread *thr) {
	duk_tval *tv;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(thr->valstack_top != thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) 2);

	tv = --thr->valstack_top;
	DUK_ASSERT(tv >= thr->valstack_bottom);
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv);  /* side effects */
#else
	DUK_TVAL_SET_UNDEFINED(tv);
#endif
	tv = --thr->valstack_top;
	DUK_ASSERT(tv >= thr->valstack_bottom);
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv);  /* side effects */
#else
	DUK_TVAL_SET_UNDEFINED(tv);
#endif

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
DUK_EXTERNAL void duk_pop_2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	if (DUK_UNLIKELY(thr->valstack_top - 2 < thr->valstack_bottom)) {
		DUK_ERROR_RANGE_INVALID_COUNT(thr);
		DUK_WO_NORETURN(return;);
	}

	duk__pop_2_unsafe_raw(thr);
}
DUK_INTERNAL void duk_pop_2_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk__pop_2_unsafe_raw(thr);
}
DUK_INTERNAL void duk_pop_2_nodecref_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_top != thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) >= (duk_size_t) 2);

	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top - 1));
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top - 2));
	thr->valstack_top -= 2;

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
}
#endif  /* !DUK_USE_PREFER_SIZE */

DUK_EXTERNAL void duk_pop_3(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n(thr, 3);
}

DUK_INTERNAL void duk_pop_3_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_unsafe(thr, 3);
}

DUK_INTERNAL void duk_pop_3_nodecref_unsafe(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_pop_n_nodecref_unsafe(thr, 3);
}

/*
 *  Pack and unpack (pack value stack entries into an array and vice versa)
 */

/* XXX: pack index range? array index offset? */
/* XXX: need ability to pack into a bare array? */
DUK_INTERNAL void duk_pack(duk_hthread *thr, duk_idx_t count) {
	duk_tval *tv_src;
	duk_tval *tv_dst;
	duk_tval *tv_curr;
	duk_tval *tv_limit;
	duk_idx_t top;

	DUK_ASSERT_API_ENTRY(thr);

	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	top = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT(top >= 0);
	if (DUK_UNLIKELY((duk_uidx_t) count > (duk_uidx_t) top)) {
		/* Also handles negative count. */
		DUK_ERROR_RANGE_INVALID_COUNT(thr);
		DUK_WO_NORETURN(return;);
	}
	DUK_ASSERT(count >= 0);

	/* Wrapping is controlled by the check above: value stack top can be
	 * at most DUK_USE_VALSTACK_LIMIT which is low enough so that
	 * multiplying with sizeof(duk_tval) won't wrap.
	 */
	DUK_ASSERT(count >= 0 && count <= (duk_idx_t) DUK_USE_VALSTACK_LIMIT);
	DUK_ASSERT((duk_size_t) count <= DUK_SIZE_MAX / sizeof(duk_tval));  /* no wrapping */

	tv_dst = duk_push_harray_with_size_outptr(thr, (duk_uint32_t) count);  /* XXX: uninitialized would be OK */
	DUK_ASSERT(count == 0 || tv_dst != NULL);
	DUK_ASSERT(!duk_is_bare_object(thr, -1));

	/* Copy value stack values directly to the array part without
	 * any refcount updates: net refcount changes are zero.
	 */
	tv_src = thr->valstack_top - count - 1;
	duk_memcpy_unsafe((void *) tv_dst, (const void *) tv_src, (size_t) count * sizeof(duk_tval));

	/* Overwrite result array to final value stack location and wipe
	 * the rest; no refcount operations needed.
	 */

	tv_dst = tv_src;  /* when count == 0, same as tv_src (OK) */
	tv_src = thr->valstack_top - 1;
	DUK_TVAL_SET_TVAL(tv_dst, tv_src);

	/* XXX: internal helper to wipe a value stack segment? */
	tv_curr = tv_dst + 1;
	tv_limit = thr->valstack_top;
	while (tv_curr != tv_limit) {
		/* Wipe policy: keep as 'undefined'. */
		DUK_TVAL_SET_UNDEFINED(tv_curr);
		tv_curr++;
	}
	thr->valstack_top = tv_dst + 1;
}

DUK_INTERNAL duk_idx_t duk_unpack_array_like(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);

	tv = duk_require_tval(thr, idx);
	if (DUK_LIKELY(DUK_TVAL_IS_OBJECT(tv))) {
		duk_hobject *h;
		duk_uint32_t len;
		duk_uint32_t i;

		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		DUK_UNREF(h);

#if defined(DUK_USE_ARRAY_FASTPATH)  /* close enough */
		if (DUK_LIKELY(DUK_HOBJECT_IS_ARRAY(h) &&
		               ((duk_harray *) h)->length <= DUK_HOBJECT_GET_ASIZE(h))) {
			duk_harray *h_arr;
			duk_tval *tv_src;
			duk_tval *tv_dst;

			h_arr = (duk_harray *) h;
			len = h_arr->length;
			if (DUK_UNLIKELY(len >= 0x80000000UL)) {
				goto fail_over_2g;
			}
			duk_require_stack(thr, (duk_idx_t) len);

			/* The potential allocation in duk_require_stack() may
			 * run a finalizer which modifies the argArray so that
			 * e.g. becomes sparse.  So, we need to recheck that the
			 * array didn't change size and that there's still a
			 * valid backing array part.
			 *
			 * XXX: alternatively, could prevent finalizers for the
			 * duration.
			 */
			if (DUK_UNLIKELY(len != h_arr->length ||
			                 h_arr->length > DUK_HOBJECT_GET_ASIZE((duk_hobject *) h_arr))) {
				goto skip_fast;
			}

			/* Main fast path: arguments array is almost always
			 * an actual array (though it might also be an arguments
			 * object).
			 */

			DUK_DDD(DUK_DDDPRINT("fast path for %ld elements", (long) h_arr->length));
			tv_src = DUK_HOBJECT_A_GET_BASE(thr->heap, h);
			tv_dst = thr->valstack_top;
			while (len-- > 0) {
				DUK_ASSERT(tv_dst < thr->valstack_end);
				if (DUK_UNLIKELY(DUK_TVAL_IS_UNUSED(tv_src))) {
					/* Gaps are very unlikely.  Skip over them,
					 * without an ancestor lookup (technically
					 * not compliant).
					 */
					DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv_dst));  /* valstack policy */
				} else {
					DUK_TVAL_SET_TVAL(tv_dst, tv_src);
					DUK_TVAL_INCREF(thr, tv_dst);
				}
				tv_src++;
				tv_dst++;
			}
			DUK_ASSERT(tv_dst <= thr->valstack_end);
			thr->valstack_top = tv_dst;
			return (duk_idx_t) h_arr->length;
		}
	 skip_fast:
#endif  /* DUK_USE_ARRAY_FASTPATH */

		/* Slow path: actual lookups.  The initial 'length' lookup
		 * decides the output length, regardless of side effects that
		 * may resize or change the argArray while we read the
		 * indices.
		 */
		idx = duk_normalize_index(thr, idx);
		duk_get_prop_stridx(thr, idx, DUK_STRIDX_LENGTH);
		len = duk_to_uint32(thr, -1);  /* ToUint32() coercion required */
		if (DUK_UNLIKELY(len >= 0x80000000UL)) {
			goto fail_over_2g;
		}
		duk_pop_unsafe(thr);
		DUK_DDD(DUK_DDDPRINT("slow path for %ld elements", (long) len));

		duk_require_stack(thr, (duk_idx_t) len);
		for (i = 0; i < len; i++) {
			duk_get_prop_index(thr, idx, (duk_uarridx_t) i);
		}
		return (duk_idx_t) len;
	} else if (DUK_TVAL_IS_UNDEFINED(tv) || DUK_TVAL_IS_NULL(tv)) {
		return 0;
	}

	DUK_ERROR_TYPE_INVALID_ARGS(thr);
	DUK_WO_NORETURN(return 0;);

 fail_over_2g:
	DUK_ERROR_RANGE_INVALID_LENGTH(thr);
	DUK_WO_NORETURN(return 0;);
}

/*
 *  Error throwing
 */

#if defined(DUK_USE_GCC_PRAGMAS)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsuggest-attribute=noreturn"
#elif defined(DUK_USE_CLANG_PRAGMAS)
#pragma clang diagnostic push
#endif

DUK_EXTERNAL void duk_throw_raw(duk_hthread *thr) {
	duk_tval *tv_val;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);

	if (DUK_UNLIKELY(thr->valstack_top == thr->valstack_bottom)) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return;);
	}

	/* Errors are augmented when they are created, not when they are
	 * thrown or re-thrown.  The current error handler, however, runs
	 * just before an error is thrown.
	 */

	/* Sync so that augmentation sees up-to-date activations, NULL
	 * thr->ptr_curr_pc so that it's not used if side effects occur
	 * in augmentation or longjmp handling.
	 */
	duk_hthread_sync_and_null_currpc(thr);

#if defined(DUK_USE_AUGMENT_ERROR_THROW)
	DUK_DDD(DUK_DDDPRINT("THROW ERROR (API): %!dT (before throw augment)", (duk_tval *) duk_get_tval(thr, -1)));
	duk_err_augment_error_throw(thr);
#endif
	DUK_DDD(DUK_DDDPRINT("THROW ERROR (API): %!dT (after throw augment)", (duk_tval *) duk_get_tval(thr, -1)));

	tv_val = DUK_GET_TVAL_NEGIDX(thr, -1);
	duk_err_setup_ljstate1(thr, DUK_LJ_TYPE_THROW, tv_val);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_err_check_debugger_integration(thr);
#endif

	/* thr->heap->lj.jmpbuf_ptr is checked by duk_err_longjmp() so we don't
	 * need to check that here.  If the value is NULL, a fatal error occurs
	 * because we can't return.
	 */

	duk_err_longjmp(thr);
	DUK_UNREACHABLE();
}

DUK_EXTERNAL void duk_fatal_raw(duk_hthread *thr, const char *err_msg) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->heap->fatal_func != NULL);

	DUK_D(DUK_DPRINT("fatal error occurred: %s", err_msg ? err_msg : "NULL"));

	/* fatal_func should be noreturn, but noreturn declarations on function
	 * pointers has a very spotty support apparently so it's not currently
	 * done.
	 */
	thr->heap->fatal_func(thr->heap->heap_udata, err_msg);

	/* If the fatal handler returns, all bets are off.  It'd be nice to
	 * print something here but since we don't want to depend on stdio,
	 * there's no way to do so portably.
	 */
	DUK_D(DUK_DPRINT("fatal error handler returned, all bets are off!"));
	for (;;) {
		/* loop forever, don't return (function marked noreturn) */
	}
}

DUK_EXTERNAL void duk_error_va_raw(duk_hthread *thr, duk_errcode_t err_code, const char *filename, duk_int_t line, const char *fmt, va_list ap) {
	DUK_ASSERT_API_ENTRY(thr);

	duk_push_error_object_va_raw(thr, err_code, filename, line, fmt, ap);
	(void) duk_throw(thr);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_error_raw(duk_hthread *thr, duk_errcode_t err_code, const char *filename, duk_int_t line, const char *fmt, ...) {
	va_list ap;

	DUK_ASSERT_API_ENTRY(thr);

	va_start(ap, fmt);
	duk_push_error_object_va_raw(thr, err_code, filename, line, fmt, ap);
	va_end(ap);
	(void) duk_throw(thr);
	DUK_WO_NORETURN(return;);
}

#if defined(DUK_USE_GCC_PRAGMAS)
#pragma GCC diagnostic pop
#elif defined(DUK_USE_CLANG_PRAGMAS)
#pragma clang diagnostic pop
#endif

#if !defined(DUK_USE_VARIADIC_MACROS)
DUK_NORETURN(DUK_LOCAL_DECL void duk__throw_error_from_stash(duk_hthread *thr, duk_errcode_t err_code, const char *fmt, va_list ap));

DUK_LOCAL void duk__throw_error_from_stash(duk_hthread *thr, duk_errcode_t err_code, const char *fmt, va_list ap) {
	const char *filename;
	duk_int_t line;

	DUK_CTX_ASSERT_VALID(thr);

	filename = duk_api_global_filename;
	line = duk_api_global_line;
	duk_api_global_filename = NULL;
	duk_api_global_line = 0;

	duk_push_error_object_va_raw(thr, err_code, filename, line, fmt, ap);
	(void) duk_throw(thr);
	DUK_WO_NORETURN(return;);
}

#define DUK__ERROR_STASH_SHARED(code) do { \
		va_list ap; \
		va_start(ap, fmt); \
		duk__throw_error_from_stash(thr, (code), fmt, ap); \
		va_end(ap); \
		DUK_WO_NORETURN(return 0;); \
	} while (0)

DUK_EXTERNAL duk_ret_t duk_error_stash(duk_hthread *thr, duk_errcode_t err_code, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(err_code);
}
DUK_EXTERNAL duk_ret_t duk_generic_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_eval_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_EVAL_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_range_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_RANGE_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_reference_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_REFERENCE_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_syntax_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_SYNTAX_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_type_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_TYPE_ERROR);
}
DUK_EXTERNAL duk_ret_t duk_uri_error_stash(duk_hthread *thr, const char *fmt, ...) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK__ERROR_STASH_SHARED(DUK_ERR_URI_ERROR);
}
#endif  /* DUK_USE_VARIADIC_MACROS */

/*
 *  Comparison
 */

DUK_EXTERNAL duk_bool_t duk_equals(duk_hthread *thr, duk_idx_t idx1, duk_idx_t idx2) {
	duk_tval *tv1, *tv2;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_get_tval(thr, idx1);
	tv2 = duk_get_tval(thr, idx2);
	if ((tv1 == NULL) || (tv2 == NULL)) {
		return 0;
	}

	/* Coercion may be needed, the helper handles that by pushing the
	 * tagged values to the stack.
	 */
	return duk_js_equals(thr, tv1, tv2);
}

DUK_EXTERNAL duk_bool_t duk_strict_equals(duk_hthread *thr, duk_idx_t idx1, duk_idx_t idx2) {
	duk_tval *tv1, *tv2;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_get_tval(thr, idx1);
	tv2 = duk_get_tval(thr, idx2);
	if ((tv1 == NULL) || (tv2 == NULL)) {
		return 0;
	}

	/* No coercions or other side effects, so safe */
	return duk_js_strict_equals(tv1, tv2);
}

DUK_EXTERNAL duk_bool_t duk_samevalue(duk_hthread *thr, duk_idx_t idx1, duk_idx_t idx2) {
	duk_tval *tv1, *tv2;

	DUK_ASSERT_API_ENTRY(thr);

	tv1 = duk_get_tval(thr, idx1);
	tv2 = duk_get_tval(thr, idx2);
	if ((tv1 == NULL) || (tv2 == NULL)) {
		return 0;
	}

	/* No coercions or other side effects, so safe */
	return duk_js_samevalue(tv1, tv2);
}

/*
 *  instanceof
 */

DUK_EXTERNAL duk_bool_t duk_instanceof(duk_hthread *thr, duk_idx_t idx1, duk_idx_t idx2) {
	duk_tval *tv1, *tv2;

	DUK_ASSERT_API_ENTRY(thr);

	/* Index validation is strict, which differs from duk_equals().
	 * The strict behavior mimics how instanceof itself works, e.g.
	 * it is a TypeError if rval is not a -callable- object.  It would
	 * be somewhat inconsistent if rval would be allowed to be
	 * non-existent without a TypeError.
	 */
	tv1 = duk_require_tval(thr, idx1);
	DUK_ASSERT(tv1 != NULL);
	tv2 = duk_require_tval(thr, idx2);
	DUK_ASSERT(tv2 != NULL);

	return duk_js_instanceof(thr, tv1, tv2);
}

/*
 *  Lightfunc
 */

DUK_INTERNAL void duk_push_lightfunc_name_raw(duk_hthread *thr, duk_c_function func, duk_small_uint_t lf_flags) {
	/* Lightfunc name, includes Duktape/C native function pointer, which
	 * can often be used to locate the function from a symbol table.
	 * The name also includes the 16-bit duk_tval flags field because it
	 * includes the magic value.  Because a single native function often
	 * provides different functionality depending on the magic value, it
	 * seems reasonably to include it in the name.
	 *
	 * On the other hand, a complicated name increases string table
	 * pressure in low memory environments (but only when function name
	 * is accessed).
	 */

	DUK_ASSERT_API_ENTRY(thr);

	duk_push_literal(thr, "light_");
	duk_push_string_funcptr(thr, (duk_uint8_t *) &func, sizeof(func));
	duk_push_sprintf(thr, "_%04x", (unsigned int) lf_flags);
	duk_concat(thr, 3);
}

DUK_INTERNAL void duk_push_lightfunc_name(duk_hthread *thr, duk_tval *tv) {
	duk_c_function func;
	duk_small_uint_t lf_flags;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv));

	DUK_TVAL_GET_LIGHTFUNC(tv, func, lf_flags);
	duk_push_lightfunc_name_raw(thr, func, lf_flags);
}

DUK_INTERNAL void duk_push_lightfunc_tostring(duk_hthread *thr, duk_tval *tv) {
	duk_c_function func;
	duk_small_uint_t lf_flags;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv));

	DUK_TVAL_GET_LIGHTFUNC(tv, func, lf_flags);  /* read before 'tv' potentially invalidated */
	duk_push_literal(thr, "function ");
	duk_push_lightfunc_name_raw(thr, func, lf_flags);
	duk_push_literal(thr, "() { [lightfunc code] }");
	duk_concat(thr, 3);
}

/*
 *  Function pointers
 *
 *  Printing function pointers is non-portable, so we do that by hex printing
 *  bytes from memory.
 */

DUK_INTERNAL void duk_push_string_funcptr(duk_hthread *thr, duk_uint8_t *ptr, duk_size_t sz) {
	duk_uint8_t buf[32 * 2];
	duk_uint8_t *p, *q;
	duk_small_uint_t i;
	duk_small_uint_t t;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(sz <= 32);  /* sanity limit for function pointer size */

	p = buf;
#if defined(DUK_USE_INTEGER_LE)
	q = ptr + sz;
#else
	q = ptr;
#endif
	for (i = 0; i < sz; i++) {
#if defined(DUK_USE_INTEGER_LE)
		t = *(--q);
#else
		t = *(q++);
#endif
		*p++ = duk_lc_digits[t >> 4];
		*p++ = duk_lc_digits[t & 0x0f];
	}

	duk_push_lstring(thr, (const char *) buf, sz * 2);
}

/*
 *  Push readable string summarizing duk_tval.  The operation is side effect
 *  free and will only throw from internal errors (e.g. out of memory).
 *  This is used by e.g. property access code to summarize a key/base safely,
 *  and is not intended to be fast (but small and safe).
 */

/* String limits for summary strings. */
#define DUK__READABLE_SUMMARY_MAXCHARS 96  /* maximum supported by helper */
#define DUK__READABLE_STRING_MAXCHARS  32  /* for strings/symbols */
#define DUK__READABLE_ERRMSG_MAXCHARS  96  /* for error messages */

/* String sanitizer which escapes ASCII control characters and a few other
 * ASCII characters, passes Unicode as is, and replaces invalid UTF-8 with
 * question marks.  No errors are thrown for any input string, except in out
 * of memory situations.
 */
DUK_LOCAL void duk__push_hstring_readable_unicode(duk_hthread *thr, duk_hstring *h_input, duk_small_uint_t maxchars) {
	const duk_uint8_t *p, *p_start, *p_end;
	duk_uint8_t buf[DUK_UNICODE_MAX_XUTF8_LENGTH * DUK__READABLE_SUMMARY_MAXCHARS +
	                2 /*quotes*/ + 3 /*periods*/];
	duk_uint8_t *q;
	duk_ucodepoint_t cp;
	duk_small_uint_t nchars;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(h_input != NULL);
	DUK_ASSERT(maxchars <= DUK__READABLE_SUMMARY_MAXCHARS);

	p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
	p = p_start;
	q = buf;

	nchars = 0;
	*q++ = (duk_uint8_t) DUK_ASC_SINGLEQUOTE;
	for (;;) {
		if (p >= p_end) {
			break;
		}
		if (nchars == maxchars) {
			*q++ = (duk_uint8_t) DUK_ASC_PERIOD;
			*q++ = (duk_uint8_t) DUK_ASC_PERIOD;
			*q++ = (duk_uint8_t) DUK_ASC_PERIOD;
			break;
		}
		if (duk_unicode_decode_xutf8(thr, &p, p_start, p_end, &cp)) {
			if (cp < 0x20 || cp == 0x7f || cp == DUK_ASC_SINGLEQUOTE || cp == DUK_ASC_BACKSLASH) {
				DUK_ASSERT(DUK_UNICODE_MAX_XUTF8_LENGTH >= 4);  /* estimate is valid */
				DUK_ASSERT((cp >> 4) <= 0x0f);
				*q++ = (duk_uint8_t) DUK_ASC_BACKSLASH;
				*q++ = (duk_uint8_t) DUK_ASC_LC_X;
				*q++ = (duk_uint8_t) duk_lc_digits[cp >> 4];
				*q++ = (duk_uint8_t) duk_lc_digits[cp & 0x0f];
			} else {
				q += duk_unicode_encode_xutf8(cp, q);
			}
		} else {
			p++;  /* advance manually */
			*q++ = (duk_uint8_t) DUK_ASC_QUESTION;
		}
		nchars++;
	}
	*q++ = (duk_uint8_t) DUK_ASC_SINGLEQUOTE;

	duk_push_lstring(thr, (const char *) buf, (duk_size_t) (q - buf));
}

DUK_LOCAL const char *duk__push_string_tval_readable(duk_hthread *thr, duk_tval *tv, duk_bool_t error_aware) {
	DUK_CTX_ASSERT_VALID(thr);
	/* 'tv' may be NULL */

	if (tv == NULL) {
		duk_push_literal(thr, "none");
	} else {
		switch (DUK_TVAL_GET_TAG(tv)) {
		case DUK_TAG_STRING: {
			duk_hstring *h = DUK_TVAL_GET_STRING(tv);
			if (DUK_HSTRING_HAS_SYMBOL(h)) {
				/* XXX: string summary produces question marks
				 * so this is not very ideal.
				 */
				duk_push_literal(thr, "[Symbol ");
				duk_push_string(thr, duk__get_symbol_type_string(h));
				duk_push_literal(thr, " ");
				duk__push_hstring_readable_unicode(thr, h, DUK__READABLE_STRING_MAXCHARS);
				duk_push_literal(thr, "]");
				duk_concat(thr, 5);
				break;
			}
			duk__push_hstring_readable_unicode(thr, h, DUK__READABLE_STRING_MAXCHARS);
			break;
		}
		case DUK_TAG_OBJECT: {
			duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
			DUK_ASSERT(h != NULL);

			if (error_aware &&
			    duk_hobject_prototype_chain_contains(thr, h, thr->builtins[DUK_BIDX_ERROR_PROTOTYPE], 1 /*ignore_loop*/)) {
				/* Get error message in a side effect free way if
				 * possible; if not, summarize as a generic object.
				 * Error message currently gets quoted.
				 */
				/* XXX: better internal getprop call; get without side effects
				 * but traverse inheritance chain.
				 */
				duk_tval *tv_msg;
				tv_msg = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, h, DUK_STRIDX_MESSAGE);
				if (tv_msg != NULL && DUK_TVAL_IS_STRING(tv_msg)) {
					/* It's critical to avoid recursion so
					 * only summarize a string .message.
					 */
					duk__push_hstring_readable_unicode(thr, DUK_TVAL_GET_STRING(tv_msg), DUK__READABLE_ERRMSG_MAXCHARS);
					break;
				}
			}
			duk_push_class_string_tval(thr, tv, 1 /*avoid_side_effects*/);
			break;
		}
		case DUK_TAG_BUFFER: {
			/* While plain buffers mimic Uint8Arrays, they summarize differently.
			 * This is useful so that the summarized string accurately reflects the
			 * internal type which may matter for figuring out bugs etc.
			 */
			/* XXX: Hex encoded, length limited buffer summary here? */
			duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
			DUK_ASSERT(h != NULL);
			duk_push_sprintf(thr, "[buffer:%ld]", (long) DUK_HBUFFER_GET_SIZE(h));
			break;
		}
		case DUK_TAG_POINTER: {
			/* Surround with parentheses like in JX, ensures NULL pointer
			 * is distinguishable from null value ("(null)" vs "null").
			 */
			duk_push_tval(thr, tv);
			duk_push_sprintf(thr, "(%s)", duk_to_string(thr, -1));
			duk_remove_m2(thr);
			break;
		}
		default: {
			duk_push_tval(thr, tv);
			break;
		}
		}
	}

	return duk_to_string(thr, -1);
}
DUK_INTERNAL const char *duk_push_string_tval_readable(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__push_string_tval_readable(thr, tv, 0 /*error_aware*/);
}

DUK_INTERNAL const char *duk_push_string_readable(duk_hthread *thr, duk_idx_t idx) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk_push_string_tval_readable(thr, duk_get_tval(thr, idx));
}

DUK_INTERNAL const char *duk_push_string_tval_readable_error(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT_API_ENTRY(thr);
	return duk__push_string_tval_readable(thr, tv, 1 /*error_aware*/);
}

DUK_INTERNAL void duk_push_symbol_descriptive_string(duk_hthread *thr, duk_hstring *h) {
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	const duk_uint8_t *q;

	DUK_ASSERT_API_ENTRY(thr);

	/* .toString() */
	duk_push_literal(thr, "Symbol(");
	p = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	p_end = p + DUK_HSTRING_GET_BYTELEN(h);
	DUK_ASSERT(p[0] == 0xff || (p[0] & 0xc0) == 0x80);
	p++;
	for (q = p; q < p_end; q++) {
		if (*q == 0xffU) {
			/* Terminate either at end-of-string (but NUL MUST
			 * be accepted without terminating description) or
			 * 0xFF, which is used to mark start of unique trailer
			 * (and cannot occur in CESU-8 / extended UTF-8).
			 */
			break;
		}
	}
	duk_push_lstring(thr, (const char *) p, (duk_size_t) (q - p));
	duk_push_literal(thr, ")");
	duk_concat(thr, 3);
}

/*
 *  Functions
 */

#if 0  /* not used yet */
DUK_INTERNAL void duk_push_hnatfunc_name(duk_hthread *thr, duk_hnatfunc *h) {
	duk_c_function func;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC((duk_hobject *) h));

	duk_push_sprintf(thr, "native_");
	func = h->func;
	duk_push_string_funcptr(thr, (duk_uint8_t *) &func, sizeof(func));
	duk_push_sprintf(thr, "_%04x_%04x",
	                 (unsigned int) (duk_uint16_t) h->nargs,
	                 (unsigned int) (duk_uint16_t) h->magic);
	duk_concat(thr, 3);
}
#endif

/*
 *  duk_tval slice copy
 */

DUK_INTERNAL void duk_copy_tvals_incref(duk_hthread *thr, duk_tval *tv_dst, duk_tval *tv_src, duk_size_t count) {
	duk_tval *tv;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(thr);
	DUK_ASSERT(count * sizeof(duk_tval) >= count);  /* no wrap */

	duk_memcpy_unsafe((void *) tv_dst, (const void *) tv_src, count * sizeof(duk_tval));

	tv = tv_dst;
	while (count-- > 0) {
		DUK_TVAL_INCREF(thr, tv);
		tv++;
	}
}

/* automatic undefs */
#undef DUK__ASSERT_SPACE
#undef DUK__CHECK_SPACE
#undef DUK__ERROR_STASH_SHARED
#undef DUK__PACK_ARGS
#undef DUK__READABLE_ERRMSG_MAXCHARS
#undef DUK__READABLE_STRING_MAXCHARS
#undef DUK__READABLE_SUMMARY_MAXCHARS
/*
 *  String manipulation
 */

/* #include duk_internal.h -> already included */

DUK_LOCAL void duk__concat_and_join_helper(duk_hthread *thr, duk_idx_t count_in, duk_bool_t is_join) {
	duk_uint_t count;
	duk_uint_t i;
	duk_size_t idx;
	duk_size_t len;
	duk_hstring *h;
	duk_uint8_t *buf;

	DUK_CTX_ASSERT_VALID(thr);

	if (DUK_UNLIKELY(count_in <= 0)) {
		if (count_in < 0) {
			DUK_ERROR_RANGE_INVALID_COUNT(thr);
			DUK_WO_NORETURN(return;);
		}
		DUK_ASSERT(count_in == 0);
		duk_push_hstring_empty(thr);
		return;
	}
	count = (duk_uint_t) count_in;

	if (is_join) {
		duk_size_t t1, t2, limit;
		h = duk_to_hstring(thr, -((duk_idx_t) count) - 1);
		DUK_ASSERT(h != NULL);

		/* A bit tricky overflow test, see doc/code-issues.rst. */
		t1 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h);
		t2 = (duk_size_t) (count - 1);
		limit = (duk_size_t) DUK_HSTRING_MAX_BYTELEN;
		if (DUK_UNLIKELY(t2 != 0 && t1 > limit / t2)) {
			/* Combined size of separators already overflows. */
			goto error_overflow;
		}
		len = (duk_size_t) (t1 * t2);
	} else {
		len = (duk_size_t) 0;
	}

	for (i = count; i >= 1; i--) {
		duk_size_t new_len;
		h = duk_to_hstring(thr, -((duk_idx_t) i));
		new_len = len + (duk_size_t) DUK_HSTRING_GET_BYTELEN(h);

		/* Impose a string maximum length, need to handle overflow
		 * correctly.
		 */
		if (new_len < len ||  /* wrapped */
		    new_len > (duk_size_t) DUK_HSTRING_MAX_BYTELEN) {
			goto error_overflow;
		}
		len = new_len;
	}

	DUK_DDD(DUK_DDDPRINT("join/concat %lu strings, total length %lu bytes",
	                     (unsigned long) count, (unsigned long) len));

	/* Use stack allocated buffer to ensure reachability in errors
	 * (e.g. intern error).
	 */
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len);
	DUK_ASSERT(buf != NULL);

	/* [ ... (sep) str1 str2 ... strN buf ] */

	idx = 0;
	for (i = count; i >= 1; i--) {
		if (is_join && i != count) {
			h = duk_require_hstring(thr, -((duk_idx_t) count) - 2);  /* extra -1 for buffer */
			duk_memcpy(buf + idx, DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
			idx += DUK_HSTRING_GET_BYTELEN(h);
		}
		h = duk_require_hstring(thr, -((duk_idx_t) i) - 1);  /* extra -1 for buffer */
		duk_memcpy(buf + idx, DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
		idx += DUK_HSTRING_GET_BYTELEN(h);
	}

	DUK_ASSERT(idx == len);

	/* [ ... (sep) str1 str2 ... strN buf ] */

	/* Get rid of the strings early to minimize memory use before intern. */

	if (is_join) {
		duk_replace(thr, -((duk_idx_t) count) - 2);  /* overwrite sep */
		duk_pop_n(thr, (duk_idx_t) count);
	} else {
		duk_replace(thr, -((duk_idx_t) count) - 1);  /* overwrite str1 */
		duk_pop_n(thr, (duk_idx_t) (count - 1));
	}

	/* [ ... buf ] */

	(void) duk_buffer_to_string(thr, -1);  /* Safe if inputs are safe. */

	/* [ ... res ] */
	return;

 error_overflow:
	DUK_ERROR_RANGE(thr, DUK_STR_RESULT_TOO_LONG);
	DUK_WO_NORETURN(return;);
}

DUK_EXTERNAL void duk_concat(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);

	duk__concat_and_join_helper(thr, count, 0 /*is_join*/);
}

#if defined(DUK_USE_PREFER_SIZE)
DUK_INTERNAL void duk_concat_2(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	duk_concat(thr, 2);
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_INTERNAL void duk_concat_2(duk_hthread *thr) {
	duk_hstring *h1;
	duk_hstring *h2;
	duk_uint8_t *buf;
	duk_size_t len1;
	duk_size_t len2;
	duk_size_t len;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(duk_get_top(thr) >= 2);  /* Trusted caller. */

	h1 = duk_to_hstring(thr, -2);
	h2 = duk_to_hstring(thr, -1);
	len1 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h1);
	len2 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h2);
	len = len1 + len2;
	if (DUK_UNLIKELY(len < len1 ||  /* wrapped */
	                 len > (duk_size_t) DUK_HSTRING_MAX_BYTELEN)) {
		goto error_overflow;
	}
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len);
	DUK_ASSERT(buf != NULL);

	duk_memcpy((void *) buf, (const void *) DUK_HSTRING_GET_DATA(h1), (size_t) len1);
	duk_memcpy((void *) (buf + len1), (const void *) DUK_HSTRING_GET_DATA(h2), (size_t) len2);
	(void) duk_buffer_to_string(thr, -1);  /* Safe if inputs are safe. */

	/* [ ... str1 str2 buf ] */

	duk_replace(thr, -3);
	duk_pop_unsafe(thr);
	return;

 error_overflow:
	DUK_ERROR_RANGE(thr, DUK_STR_RESULT_TOO_LONG);
	DUK_WO_NORETURN(return;);
}
#endif  /* DUK_USE_PREFER_SIZE */

DUK_EXTERNAL void duk_join(duk_hthread *thr, duk_idx_t count) {
	DUK_ASSERT_API_ENTRY(thr);

	duk__concat_and_join_helper(thr, count, 1 /*is_join*/);
}

/* XXX: could map/decode be unified with duk_unicode_support.c code?
 * Case conversion needs also the character surroundings though.
 */

DUK_EXTERNAL void duk_decode_string(duk_hthread *thr, duk_idx_t idx, duk_decode_char_function callback, void *udata) {
	duk_hstring *h_input;
	const duk_uint8_t *p, *p_start, *p_end;
	duk_codepoint_t cp;

	DUK_ASSERT_API_ENTRY(thr);

	h_input = duk_require_hstring(thr, idx);  /* Accept symbols. */
	DUK_ASSERT(h_input != NULL);

	p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
	p = p_start;

	for (;;) {
		if (p >= p_end) {
			break;
		}
		cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p, p_start, p_end);
		callback(udata, cp);
	}
}

DUK_EXTERNAL void duk_map_string(duk_hthread *thr, duk_idx_t idx, duk_map_char_function callback, void *udata) {
	duk_hstring *h_input;
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
	const duk_uint8_t *p, *p_start, *p_end;
	duk_codepoint_t cp;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_normalize_index(thr, idx);

	h_input = duk_require_hstring(thr, idx);  /* Accept symbols. */
	DUK_ASSERT(h_input != NULL);

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(thr, bw, DUK_HSTRING_GET_BYTELEN(h_input));  /* Reasonable output estimate. */

	p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
	p = p_start;

	for (;;) {
		/* XXX: could write output in chunks with fewer ensure calls,
		 * but relative benefit would be small here.
		 */

		if (p >= p_end) {
			break;
		}
		cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p, p_start, p_end);
		cp = callback(udata, cp);

		DUK_BW_WRITE_ENSURE_XUTF8(thr, bw, cp);
	}

	DUK_BW_COMPACT(thr, bw);
	(void) duk_buffer_to_string(thr, -1);  /* Safe, extended UTF-8 encoded. */
	duk_replace(thr, idx);
}

DUK_EXTERNAL void duk_substring(duk_hthread *thr, duk_idx_t idx, duk_size_t start_offset, duk_size_t end_offset) {
	duk_hstring *h;
	duk_hstring *res;
	duk_size_t start_byte_offset;
	duk_size_t end_byte_offset;
	duk_size_t charlen;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);  /* Accept symbols. */
	h = duk_require_hstring(thr, idx);
	DUK_ASSERT(h != NULL);

	charlen = DUK_HSTRING_GET_CHARLEN(h);
	if (end_offset >= charlen) {
		end_offset = charlen;
	}
	if (start_offset > end_offset) {
		start_offset = end_offset;
	}

	DUK_ASSERT_DISABLE(start_offset >= 0);
	DUK_ASSERT(start_offset <= end_offset && start_offset <= DUK_HSTRING_GET_CHARLEN(h));
	DUK_ASSERT_DISABLE(end_offset >= 0);
	DUK_ASSERT(end_offset >= start_offset && end_offset <= DUK_HSTRING_GET_CHARLEN(h));

	/* Guaranteed by string limits. */
	DUK_ASSERT(start_offset <= DUK_UINT32_MAX);
	DUK_ASSERT(end_offset <= DUK_UINT32_MAX);

	start_byte_offset = (duk_size_t) duk_heap_strcache_offset_char2byte(thr, h, (duk_uint_fast32_t) start_offset);
	end_byte_offset = (duk_size_t) duk_heap_strcache_offset_char2byte(thr, h, (duk_uint_fast32_t) end_offset);

	DUK_ASSERT(end_byte_offset >= start_byte_offset);
	DUK_ASSERT(end_byte_offset - start_byte_offset <= DUK_UINT32_MAX);  /* Guaranteed by string limits. */

	/* No size check is necessary. */
	res = duk_heap_strtable_intern_checked(thr,
	                                       DUK_HSTRING_GET_DATA(h) + start_byte_offset,
	                                       (duk_uint32_t) (end_byte_offset - start_byte_offset));

	duk_push_hstring(thr, res);
	duk_replace(thr, idx);
}

/* XXX: this is quite clunky.  Add Unicode helpers to scan backwards and
 * forwards with a callback to process codepoints?
 */
DUK_EXTERNAL void duk_trim(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;
	const duk_uint8_t *p, *p_start, *p_end, *p_tmp1, *p_tmp2;  /* pointers for scanning */
	const duk_uint8_t *q_start, *q_end;  /* start (incl) and end (excl) of trimmed part */
	duk_codepoint_t cp;

	DUK_ASSERT_API_ENTRY(thr);

	idx = duk_require_normalize_index(thr, idx);  /* Accept symbols. */
	h = duk_require_hstring(thr, idx);
	DUK_ASSERT(h != NULL);

	p_start = DUK_HSTRING_GET_DATA(h);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h);

	p = p_start;
	while (p < p_end) {
		p_tmp1 = p;
		cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p_tmp1, p_start, p_end);
		if (!(duk_unicode_is_whitespace(cp) || duk_unicode_is_line_terminator(cp))) {
			break;
		}
		p = p_tmp1;
	}
	q_start = p;
	if (p == p_end) {
		/* Entire string is whitespace. */
		q_end = p;
		goto scan_done;
	}

	p = p_end;
	while (p > p_start) {
		p_tmp1 = p;
		while (p > p_start) {
			p--;
			if (((*p) & 0xc0) != 0x80) {
				break;
			}
		}
		p_tmp2 = p;

		cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p_tmp2, p_start, p_end);
		if (!(duk_unicode_is_whitespace(cp) || duk_unicode_is_line_terminator(cp))) {
			p = p_tmp1;
			break;
		}
	}
	q_end = p;

 scan_done:
	/* This may happen when forward and backward scanning disagree
	 * (possible for non-extended-UTF-8 strings).
	 */
	if (q_end < q_start) {
		q_end = q_start;
	}

	DUK_ASSERT(q_start >= p_start && q_start <= p_end);
	DUK_ASSERT(q_end >= p_start && q_end <= p_end);
	DUK_ASSERT(q_end >= q_start);

	DUK_DDD(DUK_DDDPRINT("trim: p_start=%p, p_end=%p, q_start=%p, q_end=%p",
	                     (const void *) p_start, (const void *) p_end,
	                     (const void *) q_start, (const void *) q_end));

	if (q_start == p_start && q_end == p_end) {
		DUK_DDD(DUK_DDDPRINT("nothing was trimmed: avoid interning (hashing etc)"));
		return;
	}

	duk_push_lstring(thr, (const char *) q_start, (duk_size_t) (q_end - q_start));
	duk_replace(thr, idx);
}

DUK_EXTERNAL duk_codepoint_t duk_char_code_at(duk_hthread *thr, duk_idx_t idx, duk_size_t char_offset) {
	duk_hstring *h;
	duk_ucodepoint_t cp;

	DUK_ASSERT_API_ENTRY(thr);

	/* XXX: Share code with String.prototype.charCodeAt?  Main difference
	 * is handling of clamped offsets.
	 */

	h = duk_require_hstring(thr, idx);  /* Accept symbols. */
	DUK_ASSERT(h != NULL);

	DUK_ASSERT_DISABLE(char_offset >= 0);  /* Always true, arg is unsigned. */
	if (char_offset >= DUK_HSTRING_GET_CHARLEN(h)) {
		return 0;
	}

	DUK_ASSERT(char_offset <= DUK_UINT_MAX);  /* Guaranteed by string limits. */
	cp = duk_hstring_char_code_at_raw(thr, h, (duk_uint_t) char_offset, 0 /*surrogate_aware*/);
	return (duk_codepoint_t) cp;
}
/*
 *  Date/time.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL duk_double_t duk_time_get_ecmascript_time(duk_hthread *thr) {
	/* ECMAScript time, with millisecond fractions.  Exposed via
	 * duk_get_now() for example.
	 */
	DUK_UNREF(thr);
	return (duk_double_t) DUK_USE_DATE_GET_NOW(thr);
}

DUK_INTERNAL duk_double_t duk_time_get_ecmascript_time_nofrac(duk_hthread *thr) {
	/* ECMAScript time without millisecond fractions.  Exposed via
	 * the Date built-in which doesn't allow fractions.
	 */
	DUK_UNREF(thr);
	return (duk_double_t) DUK_FLOOR(DUK_USE_DATE_GET_NOW(thr));
}

DUK_INTERNAL duk_double_t duk_time_get_monotonic_time(duk_hthread *thr) {
	DUK_UNREF(thr);
#if defined(DUK_USE_GET_MONOTONIC_TIME)
	return (duk_double_t) DUK_USE_GET_MONOTONIC_TIME(thr);
#else
	return (duk_double_t) DUK_USE_DATE_GET_NOW(thr);
#endif
}

DUK_EXTERNAL duk_double_t duk_get_now(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(thr);

	/* This API intentionally allows millisecond fractions. */
	return duk_time_get_ecmascript_time(thr);
}

#if 0  /* XXX: worth exposing? */
DUK_EXTERNAL duk_double_t duk_get_monotonic_time(duk_hthread *thr) {
	DUK_ASSERT_API_ENTRY(thr);
	DUK_UNREF(thr);

	return duk_time_get_monotonic_time(thr);
}
#endif

DUK_EXTERNAL void duk_time_to_components(duk_hthread *thr, duk_double_t timeval, duk_time_components *comp) {
	duk_int_t parts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(comp != NULL);  /* XXX: or check? */
	DUK_UNREF(thr);

	/* Convert as one-based, but change month to zero-based to match the
	 * ECMAScript Date built-in behavior 1:1.
	 */
	flags = DUK_DATE_FLAG_ONEBASED | DUK_DATE_FLAG_NAN_TO_ZERO;

	duk_bi_date_timeval_to_parts(timeval, parts, dparts, flags);

	/* XXX: sub-millisecond accuracy for the API */

	DUK_ASSERT(dparts[DUK_DATE_IDX_MONTH] >= 1.0 && dparts[DUK_DATE_IDX_MONTH] <= 12.0);
	comp->year = dparts[DUK_DATE_IDX_YEAR];
	comp->month = dparts[DUK_DATE_IDX_MONTH] - 1.0;
	comp->day = dparts[DUK_DATE_IDX_DAY];
	comp->hours = dparts[DUK_DATE_IDX_HOUR];
	comp->minutes = dparts[DUK_DATE_IDX_MINUTE];
	comp->seconds = dparts[DUK_DATE_IDX_SECOND];
	comp->milliseconds = dparts[DUK_DATE_IDX_MILLISECOND];
	comp->weekday = dparts[DUK_DATE_IDX_WEEKDAY];
}

DUK_EXTERNAL duk_double_t duk_components_to_time(duk_hthread *thr, duk_time_components *comp) {
	duk_double_t d;
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_uint_t flags;

	DUK_ASSERT_API_ENTRY(thr);
	DUK_ASSERT(comp != NULL);  /* XXX: or check? */
	DUK_UNREF(thr);

	/* Match Date constructor behavior (with UTC time).  Month is given
	 * as zero-based.  Day-of-month is given as one-based so normalize
	 * it to zero-based as the internal conversion helpers expects all
	 * components to be zero-based.
	 */
	flags = 0;

	/* XXX: expensive conversion; use array format in API instead, or unify
	 * time provider and time API to use same struct?
	 */

	dparts[DUK_DATE_IDX_YEAR] = comp->year;
	dparts[DUK_DATE_IDX_MONTH] = comp->month;
	dparts[DUK_DATE_IDX_DAY] = comp->day - 1.0;
	dparts[DUK_DATE_IDX_HOUR] = comp->hours;
	dparts[DUK_DATE_IDX_MINUTE] = comp->minutes;
	dparts[DUK_DATE_IDX_SECOND] = comp->seconds;
	dparts[DUK_DATE_IDX_MILLISECOND] = comp->milliseconds;
	dparts[DUK_DATE_IDX_WEEKDAY] = 0;  /* ignored */

	d = duk_bi_date_get_timeval_from_dparts(dparts, flags);

	return d;
}
/*
 *  Array built-ins
 *
 *  Most Array built-ins are intentionally generic in ECMAScript, and are
 *  intended to work even when the 'this' binding is not an Array instance.
 *  This ECMAScript feature is also used by much real world code.  For this
 *  reason the implementations here don't assume exotic Array behavior or
 *  e.g. presence of a .length property.  However, some algorithms have a
 *  fast path for duk_harray backed actual Array instances, enabled when
 *  footprint is not a concern.
 *
 *  XXX: the "Throw" flag should be set for (almost?) all [[Put]] and
 *  [[Delete]] operations, but it's currently false throughout.  Go through
 *  all put/delete cases and check throw flag use.  Need a new API primitive
 *  which allows throws flag to be specified.
 *
 *  XXX: array lengths above 2G won't work reliably.  There are many places
 *  where one needs a full signed 32-bit range ([-0xffffffff, 0xffffffff],
 *  i.e. -33- bits).  Although array 'length' cannot be written to be outside
 *  the unsigned 32-bit range (E5.1 Section 15.4.5.1 throws a RangeError if so)
 *  some intermediate values may be above 0xffffffff and this may not be always
 *  correctly handled now (duk_uint32_t is not enough for all algorithms).
 *  For instance, push() can legitimately write entries beyond length 0xffffffff
 *  and cause a RangeError only at the end.  To do this properly, the current
 *  push() implementation tracks the array index using a 'double' instead of a
 *  duk_uint32_t (which is somewhat awkward).  See test-bi-array-push-maxlen.js.
 *
 *  On using "put" vs. "def" prop
 *  =============================
 *
 *  Code below must be careful to use the appropriate primitive as it matters
 *  for compliance.  When using "put" there may be inherited properties in
 *  Array.prototype which cause side effects when values are written.  When
 *  using "define" there are no such side effects, and many test262 test cases
 *  check for this (for real world code, such side effects are very rare).
 *  Both "put" and "define" are used in the E5.1 specification; as a rule,
 *  "put" is used when modifying an existing array (or a non-array 'this'
 *  binding) and "define" for setting values into a fresh result array.
 */

/* #include duk_internal.h -> already included */

/* Perform an intermediate join when this many elements have been pushed
 * on the value stack.
 */
#define  DUK__ARRAY_MID_JOIN_LIMIT  4096

#if defined(DUK_USE_ARRAY_BUILTIN)

/*
 *  Shared helpers.
 */

/* Shared entry code for many Array built-ins: the 'this' binding is pushed
 * on the value stack and object coerced, and the current .length is returned.
 * Note that length is left on stack (it could be popped, but that's not
 * usually necessary because call handling will clean it up automatically).
 */
DUK_LOCAL duk_uint32_t duk__push_this_obj_len_u32(duk_hthread *thr) {
	duk_uint32_t len;

	/* XXX: push more directly? */
	(void) duk_push_this_coercible_to_object(thr);
	DUK_HOBJECT_ASSERT_VALID(duk_get_hobject(thr, -1));
	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_LENGTH);
	len = duk_to_uint32(thr, -1);

	/* -> [ ... ToObject(this) ToUint32(length) ] */
	return len;
}

DUK_LOCAL duk_uint32_t duk__push_this_obj_len_u32_limited(duk_hthread *thr) {
	/* Range limited to [0, 0x7fffffff] range, i.e. range that can be
	 * represented with duk_int32_t.  Use this when the method doesn't
	 * handle the full 32-bit unsigned range correctly.
	 */
	duk_uint32_t ret = duk__push_this_obj_len_u32(thr);
	if (DUK_UNLIKELY(ret >= 0x80000000UL)) {
		DUK_ERROR_RANGE_INVALID_LENGTH(thr);
		DUK_WO_NORETURN(return 0U;);
	}
	return ret;
}

#if defined(DUK_USE_ARRAY_FASTPATH)
/* Check if 'this' binding is an Array instance (duk_harray) which satisfies
 * a few other guarantees for fast path operation.  The fast path doesn't
 * need to handle all operations, even for duk_harrays, but must handle a
 * significant fraction to improve performance.  Return a non-NULL duk_harray
 * pointer when all fast path criteria are met, NULL otherwise.
 */
DUK_LOCAL duk_harray *duk__arraypart_fastpath_this(duk_hthread *thr) {
	duk_tval *tv;
	duk_hobject *h;
	duk_uint_t flags_mask, flags_bits, flags_value;

	DUK_ASSERT(thr->valstack_bottom > thr->valstack);  /* because call in progress */
	tv = DUK_GET_THIS_TVAL_PTR(thr);

	/* Fast path requires that 'this' is a duk_harray.  Read only arrays
	 * (ROM backed) are also rejected for simplicity.
	 */
	if (!DUK_TVAL_IS_OBJECT(tv)) {
		DUK_DD(DUK_DDPRINT("reject array fast path: not an object"));
		return NULL;
	}
	h = DUK_TVAL_GET_OBJECT(tv);
	DUK_ASSERT(h != NULL);
	flags_mask = DUK_HOBJECT_FLAG_ARRAY_PART | \
	             DUK_HOBJECT_FLAG_EXOTIC_ARRAY | \
	             DUK_HEAPHDR_FLAG_READONLY;
	flags_bits = DUK_HOBJECT_FLAG_ARRAY_PART | \
	             DUK_HOBJECT_FLAG_EXOTIC_ARRAY;
	flags_value = DUK_HEAPHDR_GET_FLAGS_RAW((duk_heaphdr *) h);
	if ((flags_value & flags_mask) != flags_bits) {
		DUK_DD(DUK_DDPRINT("reject array fast path: object flag check failed"));
		return NULL;
	}

	/* In some cases a duk_harray's 'length' may be larger than the
	 * current array part allocation.  Avoid the fast path in these
	 * cases, so that all fast path code can safely assume that all
	 * items in the range [0,length[ are backed by the current array
	 * part allocation.
	 */
	if (((duk_harray *) h)->length > DUK_HOBJECT_GET_ASIZE(h)) {
		DUK_DD(DUK_DDPRINT("reject array fast path: length > array part size"));
		return NULL;
	}

	/* Guarantees for fast path. */
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_ASIZE(h) == 0 || DUK_HOBJECT_A_GET_BASE(thr->heap, h) != NULL);
	DUK_ASSERT(((duk_harray *) h)->length <= DUK_HOBJECT_GET_ASIZE(h));

	DUK_DD(DUK_DDPRINT("array fast path allowed for: %!O", (duk_heaphdr *) h));
	return (duk_harray *) h;
}
#endif  /* DUK_USE_ARRAY_FASTPATH */

/*
 *  Constructor
 */

DUK_INTERNAL duk_ret_t duk_bi_array_constructor(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_harray *a;
	duk_double_t d;
	duk_uint32_t len;
	duk_uint32_t len_prealloc;

	nargs = duk_get_top(thr);

	if (nargs == 1 && duk_is_number(thr, 0)) {
		/* XXX: expensive check (also shared elsewhere - so add a shared internal API call?) */
		d = duk_get_number(thr, 0);
		len = duk_to_uint32(thr, 0);
		if (!duk_double_equals((duk_double_t) len, d)) {
			DUK_DCERROR_RANGE_INVALID_LENGTH(thr);
		}

		/* For small lengths create a dense preallocated array.
		 * For large arrays preallocate an initial part.
		 */
		len_prealloc = len < 64 ? len : 64;
		a = duk_push_harray_with_size(thr, len_prealloc);
		DUK_ASSERT(a != NULL);
		DUK_ASSERT(!duk_is_bare_object(thr, -1));
		a->length = len;
		return 1;
	}

	duk_pack(thr, nargs);
	return 1;
}

/*
 *  isArray()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_constructor_is_array(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 1);
	duk_push_boolean(thr, duk_js_isarray(DUK_GET_TVAL_POSIDX(thr, 0)));
	return 1;
}

/*
 *  toString()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_to_string(duk_hthread *thr) {
	(void) duk_push_this_coercible_to_object(thr);
	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_JOIN);

	/* [ ... this func ] */
	if (!duk_is_callable(thr, -1)) {
		/* Fall back to the initial (original) Object.toString().  We don't
		 * currently have pointers to the built-in functions, only the top
		 * level global objects (like "Array") so this is now done in a bit
		 * of a hacky manner.  It would be cleaner to push the (original)
		 * function and use duk_call_method().
		 */

		/* XXX: 'this' will be ToObject() coerced twice, which is incorrect
		 * but should have no visible side effects.
		 */
		DUK_DDD(DUK_DDDPRINT("this.join is not callable, fall back to (original) Object.toString"));
		duk_set_top(thr, 0);
		return duk_bi_object_prototype_to_string(thr);  /* has access to 'this' binding */
	}

	/* [ ... this func ] */

	duk_insert(thr, -2);

	/* [ ... func this ] */

	DUK_DDD(DUK_DDDPRINT("calling: func=%!iT, this=%!iT",
	                     (duk_tval *) duk_get_tval(thr, -2),
	                     (duk_tval *) duk_get_tval(thr, -1)));
	duk_call_method(thr, 0);

	return 1;
}

/*
 *  concat()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_concat(duk_hthread *thr) {
	duk_idx_t i, n;
	duk_uint32_t j, idx, len;
	duk_hobject *h;
	duk_size_t tmp_len;

	/* XXX: In ES2015 Array .length can be up to 2^53-1.  The current
	 * implementation is limited to 2^32-1.
	 */

	/* XXX: Fast path for array 'this' and array element. */

	/* XXX: The insert here is a bit expensive if there are a lot of items.
	 * It could also be special cased in the outermost for loop quite easily
	 * (as the element is dup()'d anyway).
	 */

	(void) duk_push_this_coercible_to_object(thr);
	duk_insert(thr, 0);
	n = duk_get_top(thr);
	duk_push_array(thr);  /* -> [ ToObject(this) item1 ... itemN arr ] */

	/* NOTE: The Array special behaviors are NOT invoked by duk_xdef_prop_index()
	 * (which differs from the official algorithm).  If no error is thrown, this
	 * doesn't matter as the length is updated at the end.  However, if an error
	 * is thrown, the length will be unset.  That shouldn't matter because the
	 * caller won't get a reference to the intermediate value.
	 */

	idx = 0;
	for (i = 0; i < n; i++) {
		duk_bool_t spreadable;
		duk_bool_t need_has_check;

		DUK_ASSERT_TOP(thr, n + 1);

		/* [ ToObject(this) item1 ... itemN arr ] */

		h = duk_get_hobject(thr, i);

		if (h == NULL) {
			spreadable = 0;
		} else {
#if defined(DUK_USE_SYMBOL_BUILTIN)
			duk_get_prop_stridx(thr, i, DUK_STRIDX_WELLKNOWN_SYMBOL_IS_CONCAT_SPREADABLE);
			if (duk_is_undefined(thr, -1)) {
				spreadable = duk_js_isarray_hobject(h);
			} else {
				spreadable = duk_to_boolean(thr, -1);
			}
			duk_pop_nodecref_unsafe(thr);
#else
			spreadable = duk_js_isarray_hobject(h);
#endif
		}

		if (!spreadable) {
			duk_dup(thr, i);
			duk_xdef_prop_index_wec(thr, -2, idx);
			idx++;
			if (DUK_UNLIKELY(idx == 0U)) {
				/* Index after update is 0, and index written
				 * was 0xffffffffUL which is no longer a valid
				 * array index.
				 */
				goto fail_wrap;
			}
			continue;
		}

		DUK_ASSERT(duk_is_object(thr, i));
		need_has_check = (DUK_HOBJECT_IS_PROXY(h) != 0);  /* Always 0 w/o Proxy support. */

		/* [ ToObject(this) item1 ... itemN arr ] */

		tmp_len = duk_get_length(thr, i);
		len = (duk_uint32_t) tmp_len;
		if (DUK_UNLIKELY(tmp_len != (duk_size_t) len)) {
			goto fail_wrap;
		}
		if (DUK_UNLIKELY(idx + len < idx)) {
			/* Result length must be at most 0xffffffffUL to be
			 * a valid 32-bit array index.
			 */
			goto fail_wrap;
		}
		for (j = 0; j < len; j++) {
			/* For a Proxy element, an explicit 'has' check is
			 * needed to allow the Proxy to present gaps.
			 */
			if (need_has_check) {
				if (duk_has_prop_index(thr, i, j)) {
					duk_get_prop_index(thr, i, j);
					duk_xdef_prop_index_wec(thr, -2, idx);
				}
			} else {
				if (duk_get_prop_index(thr, i, j)) {
					duk_xdef_prop_index_wec(thr, -2, idx);
				} else {
					duk_pop_undefined(thr);
				}
			}
			idx++;
			DUK_ASSERT(idx != 0U);  /* Wrap check above. */
		}
	}

	/* ES5.1 has a specification "bug" in that nonexistent trailing
	 * elements don't affect the result .length.  Test262 and other
	 * engines disagree, and the specification bug was fixed in ES2015
	 * (see NOTE 1 in https://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.concat).
	 */
	duk_push_uarridx(thr, idx);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_W);

	DUK_ASSERT_TOP(thr, n + 1);
	return 1;

 fail_wrap:
	DUK_ERROR_RANGE_INVALID_LENGTH(thr);
	DUK_WO_NORETURN(return 0;);
}

/*
 *  join(), toLocaleString()
 *
 *  Note: checking valstack is necessary, but only in the per-element loop.
 *
 *  Note: the trivial approach of pushing all the elements on the value stack
 *  and then calling duk_join() fails when the array contains a large number
 *  of elements.  This problem can't be offloaded to duk_join() because the
 *  elements to join must be handled here and have special handling.  Current
 *  approach is to do intermediate joins with very large number of elements.
 *  There is no fancy handling; the prefix gets re-joined multiple times.
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_join_shared(duk_hthread *thr) {
	duk_uint32_t len, count;
	duk_uint32_t idx;
	duk_small_int_t to_locale_string = duk_get_current_magic(thr);
	duk_idx_t valstack_required;

	/* For join(), nargs is 1.  For toLocaleString(), nargs is 0 and
	 * setting the top essentially pushes an undefined to the stack,
	 * thus defaulting to a comma separator.
	 */
	duk_set_top(thr, 1);
	if (duk_is_undefined(thr, 0)) {
		duk_pop_undefined(thr);
		duk_push_hstring_stridx(thr, DUK_STRIDX_COMMA);
	} else {
		duk_to_string(thr, 0);
	}

	len = duk__push_this_obj_len_u32(thr);

	/* [ sep ToObject(this) len ] */

	DUK_DDD(DUK_DDDPRINT("sep=%!T, this=%!T, len=%lu",
	                     (duk_tval *) duk_get_tval(thr, 0),
	                     (duk_tval *) duk_get_tval(thr, 1),
	                     (unsigned long) len));

	/* The extra (+4) is tight. */
	valstack_required = (duk_idx_t) ((len >= DUK__ARRAY_MID_JOIN_LIMIT ?
	                                  DUK__ARRAY_MID_JOIN_LIMIT : len) + 4);
	duk_require_stack(thr, valstack_required);

	duk_dup_0(thr);

	/* [ sep ToObject(this) len sep ] */

	count = 0;
	idx = 0;
	for (;;) {
		DUK_DDD(DUK_DDDPRINT("join idx=%ld", (long) idx));
		if (count >= DUK__ARRAY_MID_JOIN_LIMIT ||   /* intermediate join to avoid valstack overflow */
		    idx >= len) { /* end of loop (careful with len==0) */
			/* [ sep ToObject(this) len sep str0 ... str(count-1) ] */
			DUK_DDD(DUK_DDDPRINT("mid/final join, count=%ld, idx=%ld, len=%ld",
			                     (long) count, (long) idx, (long) len));
			duk_join(thr, (duk_idx_t) count);  /* -> [ sep ToObject(this) len str ] */
			duk_dup_0(thr);                    /* -> [ sep ToObject(this) len str sep ] */
			duk_insert(thr, -2);               /* -> [ sep ToObject(this) len sep str ] */
			count = 1;
		}
		if (idx >= len) {
			/* if true, the stack already contains the final result */
			break;
		}

		duk_get_prop_index(thr, 1, (duk_uarridx_t) idx);
		if (duk_is_null_or_undefined(thr, -1)) {
			duk_pop_nodecref_unsafe(thr);
			duk_push_hstring_empty(thr);
		} else {
			if (to_locale_string) {
				duk_to_object(thr, -1);
				duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_TO_LOCALE_STRING);
				duk_insert(thr, -2);  /* -> [ ... toLocaleString ToObject(val) ] */
				duk_call_method(thr, 0);
			}
			duk_to_string(thr, -1);
		}

		count++;
		idx++;
	}

	/* [ sep ToObject(this) len sep result ] */

	return 1;
}

/*
 *  pop(), push()
 */

#if defined(DUK_USE_ARRAY_FASTPATH)
DUK_LOCAL duk_ret_t duk__array_pop_fastpath(duk_hthread *thr, duk_harray *h_arr) {
	duk_tval *tv_arraypart;
	duk_tval *tv_val;
	duk_uint32_t len;

	tv_arraypart = DUK_HOBJECT_A_GET_BASE(thr->heap, (duk_hobject *) h_arr);
	len = h_arr->length;
	if (len <= 0) {
		/* nop, return undefined */
		return 0;
	}

	len--;
	h_arr->length = len;

	/* Fast path doesn't check for an index property inherited from
	 * Array.prototype.  This is quite often acceptable; if not,
	 * disable fast path.
	 */
	DUK_ASSERT_VS_SPACE(thr);
	tv_val = tv_arraypart + len;
	if (DUK_TVAL_IS_UNUSED(tv_val)) {
		/* No net refcount change.  Value stack already has
		 * 'undefined' based on value stack init policy.
		 */
		DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));
		DUK_ASSERT(DUK_TVAL_IS_UNUSED(tv_val));
	} else {
		/* No net refcount change. */
		DUK_TVAL_SET_TVAL(thr->valstack_top, tv_val);
		DUK_TVAL_SET_UNUSED(tv_val);
	}
	thr->valstack_top++;

	/* XXX: there's no shrink check in the fast path now */

	return 1;
}
#endif  /* DUK_USE_ARRAY_FASTPATH */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_pop(duk_hthread *thr) {
	duk_uint32_t len;
	duk_uint32_t idx;
#if defined(DUK_USE_ARRAY_FASTPATH)
	duk_harray *h_arr;
#endif

	DUK_ASSERT_TOP(thr, 0);

#if defined(DUK_USE_ARRAY_FASTPATH)
	h_arr = duk__arraypart_fastpath_this(thr);
	if (h_arr) {
		return duk__array_pop_fastpath(thr, h_arr);
	}
#endif

	/* XXX: Merge fastpath check into a related call (push this, coerce length, etc)? */

	len = duk__push_this_obj_len_u32(thr);
	if (len == 0) {
		duk_push_int(thr, 0);
		duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LENGTH);
		return 0;
	}
	idx = len - 1;

	duk_get_prop_index(thr, 0, (duk_uarridx_t) idx);
	duk_del_prop_index(thr, 0, (duk_uarridx_t) idx);
	duk_push_u32(thr, idx);
	duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LENGTH);
	return 1;
}

#if defined(DUK_USE_ARRAY_FASTPATH)
DUK_LOCAL duk_ret_t duk__array_push_fastpath(duk_hthread *thr, duk_harray *h_arr) {
	duk_tval *tv_arraypart;
	duk_tval *tv_src;
	duk_tval *tv_dst;
	duk_uint32_t len;
	duk_idx_t i, n;

	len = h_arr->length;
	tv_arraypart = DUK_HOBJECT_A_GET_BASE(thr->heap, (duk_hobject *) h_arr);

	n = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
	DUK_ASSERT(n >= 0);
	DUK_ASSERT((duk_uint32_t) n <= DUK_UINT32_MAX);
	if (DUK_UNLIKELY(len + (duk_uint32_t) n < len)) {
		DUK_D(DUK_DPRINT("Array.prototype.push() would go beyond 32-bit length, throw"));
		DUK_DCERROR_RANGE_INVALID_LENGTH(thr);  /* != 0 return value returned as is by caller */
	}
	if (len + (duk_uint32_t) n > DUK_HOBJECT_GET_ASIZE((duk_hobject *) h_arr)) {
		/* Array part would need to be extended.  Rely on slow path
		 * for now.
		 *
		 * XXX: Rework hobject code a bit and add extend support.
		 */
		return 0;
	}

	tv_src = thr->valstack_bottom;
	tv_dst = tv_arraypart + len;
	for (i = 0; i < n; i++) {
		/* No net refcount change; reset value stack values to
		 * undefined to satisfy value stack init policy.
		 */
		DUK_TVAL_SET_TVAL(tv_dst, tv_src);
		DUK_TVAL_SET_UNDEFINED(tv_src);
		tv_src++;
		tv_dst++;
	}
	thr->valstack_top = thr->valstack_bottom;
	len += (duk_uint32_t) n;
	h_arr->length = len;

	DUK_ASSERT((duk_uint_t) len == len);
	duk_push_uint(thr, (duk_uint_t) len);
	return 1;
}
#endif  /* DUK_USE_ARRAY_FASTPATH */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_push(duk_hthread *thr) {
	/* Note: 'this' is not necessarily an Array object.  The push()
	 * algorithm is supposed to work for other kinds of objects too,
	 * so the algorithm has e.g. an explicit update for the 'length'
	 * property which is normally "magical" in arrays.
	 */

	duk_uint32_t len;
	duk_idx_t i, n;
#if defined(DUK_USE_ARRAY_FASTPATH)
	duk_harray *h_arr;
#endif

#if defined(DUK_USE_ARRAY_FASTPATH)
	h_arr = duk__arraypart_fastpath_this(thr);
	if (h_arr) {
		duk_ret_t rc;
		rc = duk__array_push_fastpath(thr, h_arr);
		if (rc != 0) {
			return rc;
		}
		DUK_DD(DUK_DDPRINT("array push() fast path exited, resize case"));
	}
#endif

	n = duk_get_top(thr);
	len = duk__push_this_obj_len_u32(thr);

	/* [ arg1 ... argN obj length ] */

	/* Technically Array.prototype.push() can create an Array with length
	 * longer than 2^32-1, i.e. outside the 32-bit range.  The final length
	 * is *not* wrapped to 32 bits in the specification.
	 *
	 * This implementation tracks length with a uint32 because it's much
	 * more practical.
	 *
	 * See: test-bi-array-push-maxlen.js.
	 */

	if (len + (duk_uint32_t) n < len) {
		DUK_D(DUK_DPRINT("Array.prototype.push() would go beyond 32-bit length, throw"));
		DUK_DCERROR_RANGE_INVALID_LENGTH(thr);
	}

	for (i = 0; i < n; i++) {
		duk_dup(thr, i);
		duk_put_prop_index(thr, -3, (duk_uarridx_t) (len + (duk_uint32_t) i));
	}
	len += (duk_uint32_t) n;

	duk_push_u32(thr, len);
	duk_dup_top(thr);
	duk_put_prop_stridx_short(thr, -4, DUK_STRIDX_LENGTH);

	/* [ arg1 ... argN obj length new_length ] */
	return 1;
}

/*
 *  sort()
 *
 *  Currently qsort with random pivot.  This is now really, really slow,
 *  because there is no fast path for array parts.
 *
 *  Signed indices are used because qsort() leaves and degenerate cases
 *  may use a negative offset.
 */

DUK_LOCAL duk_small_int_t duk__array_sort_compare(duk_hthread *thr, duk_int_t idx1, duk_int_t idx2) {
	duk_bool_t have1, have2;
	duk_bool_t undef1, undef2;
	duk_small_int_t ret;
	duk_idx_t idx_obj = 1;  /* fixed offsets in valstack */
	duk_idx_t idx_fn = 0;
	duk_hstring *h1, *h2;

	/* Fast exit if indices are identical.  This is valid for a non-existent property,
	 * for an undefined value, and almost always for ToString() coerced comparison of
	 * arbitrary values (corner cases where this is not the case include e.g. a an
	 * object with varying ToString() coercion).
	 *
	 * The specification does not prohibit "caching" of values read from the array, so
	 * assuming equality for comparing an index with itself falls into the category of
	 * "caching".
	 *
	 * Also, compareFn may be inconsistent, so skipping a call to compareFn here may
	 * have an effect on the final result.  The specification does not require any
	 * specific behavior for inconsistent compare functions, so again, this fast path
	 * is OK.
	 */

	if (idx1 == idx2) {
		DUK_DDD(DUK_DDDPRINT("duk__array_sort_compare: idx1=%ld, idx2=%ld -> indices identical, quick exit",
		                     (long) idx1, (long) idx2));
		return 0;
	}

	have1 = duk_get_prop_index(thr, idx_obj, (duk_uarridx_t) idx1);
	have2 = duk_get_prop_index(thr, idx_obj, (duk_uarridx_t) idx2);

	DUK_DDD(DUK_DDDPRINT("duk__array_sort_compare: idx1=%ld, idx2=%ld, have1=%ld, have2=%ld, val1=%!T, val2=%!T",
	                     (long) idx1, (long) idx2, (long) have1, (long) have2,
	                     (duk_tval *) duk_get_tval(thr, -2), (duk_tval *) duk_get_tval(thr, -1)));

	if (have1) {
		if (have2) {
			;
		} else {
			ret = -1;
			goto pop_ret;
		}
	} else {
		if (have2) {
			ret = 1;
			goto pop_ret;
		} else {
			ret = 0;
			goto pop_ret;
		}
	}

	undef1 = duk_is_undefined(thr, -2);
	undef2 = duk_is_undefined(thr, -1);
	if (undef1) {
		if (undef2) {
			ret = 0;
			goto pop_ret;
		} else {
			ret = 1;
			goto pop_ret;
		}
	} else {
		if (undef2) {
			ret = -1;
			goto pop_ret;
		} else {
			;
		}
	}

	if (!duk_is_undefined(thr, idx_fn)) {
		duk_double_t d;

		/* No need to check callable; duk_call() will do that. */
		duk_dup(thr, idx_fn);    /* -> [ ... x y fn ] */
		duk_insert(thr, -3);     /* -> [ ... fn x y ] */
		duk_call(thr, 2);        /* -> [ ... res ] */

		/* ES5 is a bit vague about what to do if the return value is
		 * not a number.  ES2015 provides a concrete description:
		 * http://www.ecma-international.org/ecma-262/6.0/#sec-sortcompare.
		 */

		d = duk_to_number_m1(thr);
		if (d < 0.0) {
			ret = -1;
		} else if (d > 0.0) {
			ret = 1;
		} else {
			/* Because NaN compares to false, NaN is handled here
			 * without an explicit check above.
			 */
			ret = 0;
		}

		duk_pop_nodecref_unsafe(thr);
		DUK_DDD(DUK_DDDPRINT("-> result %ld (from comparefn, after coercion)", (long) ret));
		return ret;
	}

	/* string compare is the default (a bit oddly) */

	/* XXX: any special handling for plain array; causes repeated coercion now? */
	h1 = duk_to_hstring(thr, -2);
	h2 = duk_to_hstring_m1(thr);
	DUK_ASSERT(h1 != NULL);
	DUK_ASSERT(h2 != NULL);

	ret = duk_js_string_compare(h1, h2);  /* retval is directly usable */
	goto pop_ret;

 pop_ret:
	duk_pop_2_unsafe(thr);
	DUK_DDD(DUK_DDDPRINT("-> result %ld", (long) ret));
	return ret;
}

DUK_LOCAL void duk__array_sort_swap(duk_hthread *thr, duk_int_t l, duk_int_t r) {
	duk_bool_t have_l, have_r;
	duk_idx_t idx_obj = 1;  /* fixed offset in valstack */

	if (l == r) {
		return;
	}

	/* swap elements; deal with non-existent elements correctly */
	have_l = duk_get_prop_index(thr, idx_obj, (duk_uarridx_t) l);
	have_r = duk_get_prop_index(thr, idx_obj, (duk_uarridx_t) r);

	if (have_r) {
		/* right exists, [[Put]] regardless whether or not left exists */
		duk_put_prop_index(thr, idx_obj, (duk_uarridx_t) l);
	} else {
		duk_del_prop_index(thr, idx_obj, (duk_uarridx_t) l);
		duk_pop_undefined(thr);
	}

	if (have_l) {
		duk_put_prop_index(thr, idx_obj, (duk_uarridx_t) r);
	} else {
		duk_del_prop_index(thr, idx_obj, (duk_uarridx_t) r);
		duk_pop_undefined(thr);
	}
}

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
/* Debug print which visualizes the qsort partitioning process. */
DUK_LOCAL void duk__debuglog_qsort_state(duk_hthread *thr, duk_int_t lo, duk_int_t hi, duk_int_t pivot) {
	char buf[4096];
	char *ptr = buf;
	duk_int_t i, n;
	n = (duk_int_t) duk_get_length(thr, 1);
	if (n > 4000) {
		n = 4000;
	}
	*ptr++ = '[';
	for (i = 0; i < n; i++) {
		if (i == pivot) {
			*ptr++ = '|';
		} else if (i == lo) {
			*ptr++ = '<';
		} else if (i == hi) {
			*ptr++ = '>';
		} else if (i >= lo && i <= hi) {
			*ptr++ = '-';
		} else {
			*ptr++ = ' ';
		}
	}
	*ptr++ = ']';
	*ptr++ = '\0';

	DUK_DDD(DUK_DDDPRINT("%s   (lo=%ld, hi=%ld, pivot=%ld)",
	                     (const char *) buf, (long) lo, (long) hi, (long) pivot));
}
#endif

DUK_LOCAL void duk__array_qsort(duk_hthread *thr, duk_int_t lo, duk_int_t hi) {
	duk_int_t p, l, r;

	/* The lo/hi indices may be crossed and hi < 0 is possible at entry. */

	DUK_DDD(DUK_DDDPRINT("duk__array_qsort: lo=%ld, hi=%ld, obj=%!T",
	                     (long) lo, (long) hi, (duk_tval *) duk_get_tval(thr, 1)));

	DUK_ASSERT_TOP(thr, 3);

	/* In some cases it may be that lo > hi, or hi < 0; these
	 * degenerate cases happen e.g. for empty arrays, and in
	 * recursion leaves.
	 */

	/* trivial cases */
	if (hi - lo < 1) {
		DUK_DDD(DUK_DDDPRINT("degenerate case, return immediately"));
		return;
	}
	DUK_ASSERT(hi > lo);
	DUK_ASSERT(hi - lo + 1 >= 2);

	/* randomized pivot selection */
	p = lo + (duk_int_t) (DUK_UTIL_GET_RANDOM_DOUBLE(thr) * (duk_double_t) (hi - lo + 1));
	DUK_ASSERT(p >= lo && p <= hi);
	DUK_DDD(DUK_DDDPRINT("lo=%ld, hi=%ld, chose pivot p=%ld", (long) lo, (long) hi, (long) p));

	/* move pivot out of the way */
	duk__array_sort_swap(thr, p, lo);
	p = lo;
	DUK_DDD(DUK_DDDPRINT("pivot moved out of the way: %!T", (duk_tval *) duk_get_tval(thr, 1)));

	l = lo + 1;
	r = hi;
	for (;;) {
		/* find elements to swap */
		for (;;) {
			DUK_DDD(DUK_DDDPRINT("left scan: l=%ld, r=%ld, p=%ld",
			                     (long) l, (long) r, (long) p));
			if (l >= hi) {
				break;
			}
			if (duk__array_sort_compare(thr, l, p) >= 0) {  /* !(l < p) */
				break;
			}
			l++;
		}
		for (;;) {
			DUK_DDD(DUK_DDDPRINT("right scan: l=%ld, r=%ld, p=%ld",
			                     (long) l, (long) r, (long) p));
			if (r <= lo) {
				break;
			}
			if (duk__array_sort_compare(thr, p, r) >= 0) {  /* !(p < r) */
				break;
			}
			r--;
		}
		if (l >= r) {
			goto done;
		}
		DUK_ASSERT(l < r);

		DUK_DDD(DUK_DDDPRINT("swap %ld and %ld", (long) l, (long) r));

		duk__array_sort_swap(thr, l, r);

		DUK_DDD(DUK_DDDPRINT("after swap: %!T", (duk_tval *) duk_get_tval(thr, 1)));
		l++;
		r--;
	}
 done:
	/* Note that 'l' and 'r' may cross, i.e. r < l */
	DUK_ASSERT(l >= lo && l <= hi);
	DUK_ASSERT(r >= lo && r <= hi);

	/* XXX: there's no explicit recursion bound here now.  For the average
	 * qsort recursion depth O(log n) that's not really necessary: e.g. for
	 * 2**32 recursion depth would be about 32 which is OK.  However, qsort
	 * worst case recursion depth is O(n) which may be a problem.
	 */

	/* move pivot to its final place */
	DUK_DDD(DUK_DDDPRINT("before final pivot swap: %!T", (duk_tval *) duk_get_tval(thr, 1)));
	duk__array_sort_swap(thr, lo, r);

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
	duk__debuglog_qsort_state(thr, lo, hi, r);
#endif

	DUK_DDD(DUK_DDDPRINT("recurse: pivot=%ld, obj=%!T", (long) r, (duk_tval *) duk_get_tval(thr, 1)));
	duk__array_qsort(thr, lo, r - 1);
	duk__array_qsort(thr, r + 1, hi);
}

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_sort(duk_hthread *thr) {
	duk_uint32_t len;

	/* XXX: len >= 0x80000000 won't work below because a signed type
	 * is needed by qsort.
	 */
	len = duk__push_this_obj_len_u32_limited(thr);

	/* stack[0] = compareFn
	 * stack[1] = ToObject(this)
	 * stack[2] = ToUint32(length)
	 */

	if (len > 0) {
		/* avoid degenerate cases, so that (len - 1) won't underflow */
		duk__array_qsort(thr, (duk_int_t) 0, (duk_int_t) (len - 1));
	}

	DUK_ASSERT_TOP(thr, 3);
	duk_pop_nodecref_unsafe(thr);
	return 1;  /* return ToObject(this) */
}

/*
 *  splice()
 */

/* XXX: this compiles to over 500 bytes now, even without special handling
 * for an array part.  Uses signed ints so does not handle full array range correctly.
 */

/* XXX: can shift() / unshift() use the same helper?
 *   shift() is (close to?) <--> splice(0, 1)
 *   unshift is (close to?) <--> splice(0, 0, [items])?
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_splice(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_uint32_t len_u32;
	duk_int_t len;
	duk_bool_t have_delcount;
	duk_int_t item_count;
	duk_int_t act_start;
	duk_int_t del_count;
	duk_int_t i, n;

	DUK_UNREF(have_delcount);

	nargs = duk_get_top(thr);
	if (nargs < 2) {
		duk_set_top(thr, 2);
		nargs = 2;
		have_delcount = 0;
	} else {
		have_delcount = 1;
	}

	/* XXX: len >= 0x80000000 won't work below because we need to be
	 * able to represent -len.
	 */
	len_u32 = duk__push_this_obj_len_u32_limited(thr);
	len = (duk_int_t) len_u32;
	DUK_ASSERT(len >= 0);

	act_start = duk_to_int_clamped(thr, 0, -len, len);
	if (act_start < 0) {
		act_start = len + act_start;
	}
	DUK_ASSERT(act_start >= 0 && act_start <= len);

#if defined(DUK_USE_NONSTD_ARRAY_SPLICE_DELCOUNT)
	if (have_delcount) {
#endif
		del_count = duk_to_int_clamped(thr, 1, 0, len - act_start);
#if defined(DUK_USE_NONSTD_ARRAY_SPLICE_DELCOUNT)
	} else {
		/* E5.1 standard behavior when deleteCount is not given would be
		 * to treat it just like if 'undefined' was given, which coerces
		 * ultimately to 0.  Real world behavior is to splice to the end
		 * of array, see test-bi-array-proto-splice-no-delcount.js.
		 */
		del_count = len - act_start;
	}
#endif

	DUK_ASSERT(nargs >= 2);
	item_count = (duk_int_t) (nargs - 2);

	DUK_ASSERT(del_count >= 0 && del_count <= len - act_start);
	DUK_ASSERT(del_count + act_start <= len);

	/* For now, restrict result array into 32-bit length range. */
	if (((duk_double_t) len) - ((duk_double_t) del_count) + ((duk_double_t) item_count) > (duk_double_t) DUK_UINT32_MAX) {
		DUK_D(DUK_DPRINT("Array.prototype.splice() would go beyond 32-bit length, throw"));
		DUK_DCERROR_RANGE_INVALID_LENGTH(thr);
	}

	duk_push_array(thr);

	/* stack[0] = start
	 * stack[1] = deleteCount
	 * stack[2...nargs-1] = items
	 * stack[nargs] = ToObject(this)               -3
	 * stack[nargs+1] = ToUint32(length)           -2
	 * stack[nargs+2] = result array               -1
	 */

	DUK_ASSERT_TOP(thr, nargs + 3);

	/* Step 9: copy elements-to-be-deleted into the result array */

	for (i = 0; i < del_count; i++) {
		if (duk_get_prop_index(thr, -3, (duk_uarridx_t) (act_start + i))) {
			duk_xdef_prop_index_wec(thr, -2, (duk_uarridx_t) i);  /* throw flag irrelevant (false in std alg) */
		} else {
			duk_pop_undefined(thr);
		}
	}
	duk_push_u32(thr, (duk_uint32_t) del_count);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_W);

	/* Steps 12 and 13: reorganize elements to make room for itemCount elements */

	if (item_count < del_count) {
		/*    [ A B C D E F G H ]    rel_index = 2, del_count 3, item count 1
		 * -> [ A B F G H ]          (conceptual intermediate step)
		 * -> [ A B . F G H ]        (placeholder marked)
		 *    [ A B C F G H ]        (actual result at this point, C will be replaced)
		 */

		DUK_ASSERT_TOP(thr, nargs + 3);

		n = len - del_count;
		for (i = act_start; i < n; i++) {
			if (duk_get_prop_index(thr, -3, (duk_uarridx_t) (i + del_count))) {
				duk_put_prop_index(thr, -4, (duk_uarridx_t) (i + item_count));
			} else {
				duk_pop_undefined(thr);
				duk_del_prop_index(thr, -3, (duk_uarridx_t) (i + item_count));
			}
		}

		DUK_ASSERT_TOP(thr, nargs + 3);

		/* loop iterator init and limit changed from standard algorithm */
		n = len - del_count + item_count;
		for (i = len - 1; i >= n; i--) {
			duk_del_prop_index(thr, -3, (duk_uarridx_t) i);
		}

		DUK_ASSERT_TOP(thr, nargs + 3);
	} else if (item_count > del_count) {
		/*    [ A B C D E F G H ]    rel_index = 2, del_count 3, item count 4
		 * -> [ A B F G H ]          (conceptual intermediate step)
		 * -> [ A B . . . . F G H ]  (placeholder marked)
		 *    [ A B C D E F F G H ]  (actual result at this point)
		 */

		DUK_ASSERT_TOP(thr, nargs + 3);

		/* loop iterator init and limit changed from standard algorithm */
		for (i = len - del_count - 1; i >= act_start; i--) {
			if (duk_get_prop_index(thr, -3, (duk_uarridx_t) (i + del_count))) {
				duk_put_prop_index(thr, -4, (duk_uarridx_t) (i + item_count));
			} else {
				duk_pop_undefined(thr);
				duk_del_prop_index(thr, -3, (duk_uarridx_t) (i + item_count));
			}
		}

		DUK_ASSERT_TOP(thr, nargs + 3);
	} else {
		/*    [ A B C D E F G H ]    rel_index = 2, del_count 3, item count 3
		 * -> [ A B F G H ]          (conceptual intermediate step)
		 * -> [ A B . . . F G H ]    (placeholder marked)
		 *    [ A B C D E F G H ]    (actual result at this point)
		 */
	}
	DUK_ASSERT_TOP(thr, nargs + 3);

	/* Step 15: insert itemCount elements into the hole made above */

	for (i = 0; i < item_count; i++) {
		duk_dup(thr, i + 2);  /* args start at index 2 */
		duk_put_prop_index(thr, -4, (duk_uarridx_t) (act_start + i));
	}

	/* Step 16: update length; note that the final length may be above 32 bit range
	 * (but we checked above that this isn't the case here)
	 */

	duk_push_u32(thr, (duk_uint32_t) (len - del_count + item_count));
	duk_put_prop_stridx_short(thr, -4, DUK_STRIDX_LENGTH);

	/* result array is already at the top of stack */
	DUK_ASSERT_TOP(thr, nargs + 3);
	return 1;
}

/*
 *  reverse()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_reverse(duk_hthread *thr) {
	duk_uint32_t len;
	duk_uint32_t middle;
	duk_uint32_t lower, upper;
	duk_bool_t have_lower, have_upper;

	len = duk__push_this_obj_len_u32(thr);
	middle = len / 2;

	/* If len <= 1, middle will be 0 and for-loop bails out
	 * immediately (0 < 0 -> false).
	 */

	for (lower = 0; lower < middle; lower++) {
		DUK_ASSERT(len >= 2);
		DUK_ASSERT_TOP(thr, 2);

		DUK_ASSERT(len >= lower + 1);
		upper = len - lower - 1;

		have_lower = duk_get_prop_index(thr, -2, (duk_uarridx_t) lower);
		have_upper = duk_get_prop_index(thr, -3, (duk_uarridx_t) upper);

		/* [ ToObject(this) ToUint32(length) lowerValue upperValue ] */

		if (have_upper) {
			duk_put_prop_index(thr, -4, (duk_uarridx_t) lower);
		} else {
			duk_del_prop_index(thr, -4, (duk_uarridx_t) lower);
			duk_pop_undefined(thr);
		}

		if (have_lower) {
			duk_put_prop_index(thr, -3, (duk_uarridx_t) upper);
		} else {
			duk_del_prop_index(thr, -3, (duk_uarridx_t) upper);
			duk_pop_undefined(thr);
		}

		DUK_ASSERT_TOP(thr, 2);
	}

	DUK_ASSERT_TOP(thr, 2);
	duk_pop_unsafe(thr);  /* -> [ ToObject(this) ] */
	return 1;
}

/*
 *  slice()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_slice(duk_hthread *thr) {
	duk_uint32_t len_u32;
	duk_int_t len;
	duk_int_t start, end;
	duk_int_t i;
	duk_uarridx_t idx;
	duk_uint32_t res_length = 0;

	/* XXX: len >= 0x80000000 won't work below because we need to be
	 * able to represent -len.
	 */
	len_u32 = duk__push_this_obj_len_u32_limited(thr);
	len = (duk_int_t) len_u32;
	DUK_ASSERT(len >= 0);

	duk_push_array(thr);

	/* stack[0] = start
	 * stack[1] = end
	 * stack[2] = ToObject(this)
	 * stack[3] = ToUint32(length)
	 * stack[4] = result array
	 */

	start = duk_to_int_clamped(thr, 0, -len, len);
	if (start < 0) {
		start = len + start;
	}
	/* XXX: could duk_is_undefined() provide defaulting undefined to 'len'
	 * (the upper limit)?
	 */
	if (duk_is_undefined(thr, 1)) {
		end = len;
	} else {
		end = duk_to_int_clamped(thr, 1, -len, len);
		if (end < 0) {
			end = len + end;
		}
	}
	DUK_ASSERT(start >= 0 && start <= len);
	DUK_ASSERT(end >= 0 && end <= len);

	idx = 0;
	for (i = start; i < end; i++) {
		DUK_ASSERT_TOP(thr, 5);
		if (duk_get_prop_index(thr, 2, (duk_uarridx_t) i)) {
			duk_xdef_prop_index_wec(thr, 4, idx);
			res_length = idx + 1;
		} else {
			duk_pop_undefined(thr);
		}
		idx++;
		DUK_ASSERT_TOP(thr, 5);
	}

	duk_push_u32(thr, res_length);
	duk_xdef_prop_stridx_short(thr, 4, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_W);

	DUK_ASSERT_TOP(thr, 5);
	return 1;
}

/*
 *  shift()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_shift(duk_hthread *thr) {
	duk_uint32_t len;
	duk_uint32_t i;

	len = duk__push_this_obj_len_u32(thr);
	if (len == 0) {
		duk_push_int(thr, 0);
		duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LENGTH);
		return 0;
	}

	duk_get_prop_index(thr, 0, 0);

	/* stack[0] = object (this)
	 * stack[1] = ToUint32(length)
	 * stack[2] = elem at index 0 (retval)
	 */

	for (i = 1; i < len; i++) {
		DUK_ASSERT_TOP(thr, 3);
		if (duk_get_prop_index(thr, 0, (duk_uarridx_t) i)) {
			/* fromPresent = true */
			duk_put_prop_index(thr, 0, (duk_uarridx_t) (i - 1));
		} else {
			/* fromPresent = false */
			duk_del_prop_index(thr, 0, (duk_uarridx_t) (i - 1));
			duk_pop_undefined(thr);
		}
	}
	duk_del_prop_index(thr, 0, (duk_uarridx_t) (len - 1));

	duk_push_u32(thr, (duk_uint32_t) (len - 1));
	duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LENGTH);

	DUK_ASSERT_TOP(thr, 3);
	return 1;
}

/*
 *  unshift()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_unshift(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_uint32_t len;
	duk_uint32_t i;

	nargs = duk_get_top(thr);
	len = duk__push_this_obj_len_u32(thr);

	/* stack[0...nargs-1] = unshift args (vararg)
	 * stack[nargs] = ToObject(this)
	 * stack[nargs+1] = ToUint32(length)
	 */

	DUK_ASSERT_TOP(thr, nargs + 2);

	/* Note: unshift() may operate on indices above unsigned 32-bit range
	 * and the final length may be >= 2**32.  However, we restrict the
	 * final result to 32-bit range for practicality.
	 */

	if (len + (duk_uint32_t) nargs < len) {
		DUK_D(DUK_DPRINT("Array.prototype.unshift() would go beyond 32-bit length, throw"));
		DUK_DCERROR_RANGE_INVALID_LENGTH(thr);
	}

	i = len;
	while (i > 0) {
		DUK_ASSERT_TOP(thr, nargs + 2);
		i--;
		/* k+argCount-1; note that may be above 32-bit range */

		if (duk_get_prop_index(thr, -2, (duk_uarridx_t) i)) {
			/* fromPresent = true */
			/* [ ... ToObject(this) ToUint32(length) val ] */
			duk_put_prop_index(thr, -3, (duk_uarridx_t) (i + (duk_uint32_t) nargs));  /* -> [ ... ToObject(this) ToUint32(length) ] */
		} else {
			/* fromPresent = false */
			/* [ ... ToObject(this) ToUint32(length) val ] */
			duk_pop_undefined(thr);
			duk_del_prop_index(thr, -2, (duk_uarridx_t) (i + (duk_uint32_t) nargs));  /* -> [ ... ToObject(this) ToUint32(length) ] */
		}
		DUK_ASSERT_TOP(thr, nargs + 2);
	}

	for (i = 0; i < (duk_uint32_t) nargs; i++) {
		DUK_ASSERT_TOP(thr, nargs + 2);
		duk_dup(thr, (duk_idx_t) i);  /* -> [ ... ToObject(this) ToUint32(length) arg[i] ] */
		duk_put_prop_index(thr, -3, (duk_uarridx_t) i);
		DUK_ASSERT_TOP(thr, nargs + 2);
	}

	DUK_ASSERT_TOP(thr, nargs + 2);
	duk_push_u32(thr, len + (duk_uint32_t) nargs);
	duk_dup_top(thr);  /* -> [ ... ToObject(this) ToUint32(length) final_len final_len ] */
	duk_put_prop_stridx_short(thr, -4, DUK_STRIDX_LENGTH);
	return 1;
}

/*
 *  indexOf(), lastIndexOf()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_indexof_shared(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_int_t i, len;
	duk_int_t from_idx;
	duk_small_int_t idx_step = duk_get_current_magic(thr);  /* idx_step is +1 for indexOf, -1 for lastIndexOf */

	/* lastIndexOf() needs to be a vararg function because we must distinguish
	 * between an undefined fromIndex and a "not given" fromIndex; indexOf() is
	 * made vararg for symmetry although it doesn't strictly need to be.
	 */

	nargs = duk_get_top(thr);
	duk_set_top(thr, 2);

	/* XXX: must be able to represent -len */
	len = (duk_int_t) duk__push_this_obj_len_u32_limited(thr);
	if (len == 0) {
		goto not_found;
	}

	/* Index clamping is a bit tricky, we must ensure that we'll only iterate
	 * through elements that exist and that the specific requirements from E5.1
	 * Sections 15.4.4.14 and 15.4.4.15 are fulfilled; especially:
	 *
	 *   - indexOf: clamp to [-len,len], negative handling -> [0,len],
	 *     if clamped result is len, for-loop bails out immediately
	 *
	 *   - lastIndexOf: clamp to [-len-1, len-1], negative handling -> [-1, len-1],
	 *     if clamped result is -1, for-loop bails out immediately
	 *
	 * If fromIndex is not given, ToInteger(undefined) = 0, which is correct
	 * for indexOf() but incorrect for lastIndexOf().  Hence special handling,
	 * and why lastIndexOf() needs to be a vararg function.
	 */

	if (nargs >= 2) {
		/* indexOf: clamp fromIndex to [-len, len]
		 * (if fromIndex == len, for-loop terminates directly)
		 *
		 * lastIndexOf: clamp fromIndex to [-len - 1, len - 1]
		 * (if clamped to -len-1 -> fromIndex becomes -1, terminates for-loop directly)
		 */
		from_idx = duk_to_int_clamped(thr,
		                              1,
		                              (idx_step > 0 ? -len : -len - 1),
		                              (idx_step > 0 ? len : len - 1));
		if (from_idx < 0) {
			/* for lastIndexOf, result may be -1 (mark immediate termination) */
			from_idx = len + from_idx;
		}
	} else {
		/* for indexOf, ToInteger(undefined) would be 0, i.e. correct, but
		 * handle both indexOf and lastIndexOf specially here.
		 */
		if (idx_step > 0) {
			from_idx = 0;
		} else {
			from_idx = len - 1;
		}
	}

	/* stack[0] = searchElement
	 * stack[1] = fromIndex
	 * stack[2] = object
	 * stack[3] = length (not needed, but not popped above)
	 */

	for (i = from_idx; i >= 0 && i < len; i += idx_step) {
		DUK_ASSERT_TOP(thr, 4);

		if (duk_get_prop_index(thr, 2, (duk_uarridx_t) i)) {
			DUK_ASSERT_TOP(thr, 5);
			if (duk_strict_equals(thr, 0, 4)) {
				duk_push_int(thr, i);
				return 1;
			}
		}

		duk_pop_unsafe(thr);
	}

 not_found:
	duk_push_int(thr, -1);
	return 1;
}

/*
 *  every(), some(), forEach(), map(), filter()
 */

#define DUK__ITER_EVERY    0
#define DUK__ITER_SOME     1
#define DUK__ITER_FOREACH  2
#define DUK__ITER_MAP      3
#define DUK__ITER_FILTER   4

/* XXX: This helper is a bit awkward because the handling for the different iteration
 * callers is quite different.  This now compiles to a bit less than 500 bytes, so with
 * 5 callers the net result is about 100 bytes / caller.
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_iter_shared(duk_hthread *thr) {
	duk_uint32_t len;
	duk_uint32_t i;
	duk_uarridx_t k;
	duk_bool_t bval;
	duk_small_int_t iter_type = duk_get_current_magic(thr);
	duk_uint32_t res_length = 0;

	/* each call this helper serves has nargs==2 */
	DUK_ASSERT_TOP(thr, 2);

	len = duk__push_this_obj_len_u32(thr);
	duk_require_callable(thr, 0);
	/* if thisArg not supplied, behave as if undefined was supplied */

	if (iter_type == DUK__ITER_MAP || iter_type == DUK__ITER_FILTER) {
		duk_push_array(thr);
	} else {
		duk_push_undefined(thr);
	}

	/* stack[0] = callback
	 * stack[1] = thisArg
	 * stack[2] = object
	 * stack[3] = ToUint32(length)  (unused, but avoid unnecessary pop)
	 * stack[4] = result array (or undefined)
	 */

	k = 0;  /* result index for filter() */
	for (i = 0; i < len; i++) {
		DUK_ASSERT_TOP(thr, 5);

		if (!duk_get_prop_index(thr, 2, (duk_uarridx_t) i)) {
			/* For 'map' trailing missing elements don't invoke the
			 * callback but count towards the result length.
			 */
			if (iter_type == DUK__ITER_MAP) {
				res_length = i + 1;
			}
			duk_pop_undefined(thr);
			continue;
		}

		/* The original value needs to be preserved for filter(), hence
		 * this funny order.  We can't re-get the value because of side
		 * effects.
		 */

		duk_dup_0(thr);
		duk_dup_1(thr);
		duk_dup_m3(thr);
		duk_push_u32(thr, i);
		duk_dup_2(thr);  /* [ ... val callback thisArg val i obj ] */
		duk_call_method(thr, 3); /* -> [ ... val retval ] */

		switch (iter_type) {
		case DUK__ITER_EVERY:
			bval = duk_to_boolean(thr, -1);
			if (!bval) {
				/* stack top contains 'false' */
				return 1;
			}
			break;
		case DUK__ITER_SOME:
			bval = duk_to_boolean(thr, -1);
			if (bval) {
				/* stack top contains 'true' */
				return 1;
			}
			break;
		case DUK__ITER_FOREACH:
			/* nop */
			break;
		case DUK__ITER_MAP:
			duk_dup_top(thr);
			duk_xdef_prop_index_wec(thr, 4, (duk_uarridx_t) i);  /* retval to result[i] */
			res_length = i + 1;
			break;
		case DUK__ITER_FILTER:
			bval = duk_to_boolean(thr, -1);
			if (bval) {
				duk_dup_m2(thr);  /* orig value */
				duk_xdef_prop_index_wec(thr, 4, (duk_uarridx_t) k);
				k++;
				res_length = k;
			}
			break;
		default:
			DUK_UNREACHABLE();
			break;
		}
		duk_pop_2_unsafe(thr);

		DUK_ASSERT_TOP(thr, 5);
	}

	switch (iter_type) {
	case DUK__ITER_EVERY:
		duk_push_true(thr);
		break;
	case DUK__ITER_SOME:
		duk_push_false(thr);
		break;
	case DUK__ITER_FOREACH:
		duk_push_undefined(thr);
		break;
	case DUK__ITER_MAP:
	case DUK__ITER_FILTER:
		DUK_ASSERT_TOP(thr, 5);
		DUK_ASSERT(duk_is_array(thr, -1));  /* topmost element is the result array already */
		duk_push_u32(thr, res_length);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_W);
		break;
	default:
		DUK_UNREACHABLE();
		break;
	}

	return 1;
}

/*
 *  reduce(), reduceRight()
 */

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_reduce_shared(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_bool_t have_acc;
	duk_uint32_t i, len;
	duk_small_int_t idx_step = duk_get_current_magic(thr);  /* idx_step is +1 for reduce, -1 for reduceRight */

	/* We're a varargs function because we need to detect whether
	 * initialValue was given or not.
	 */
	nargs = duk_get_top(thr);
	DUK_DDD(DUK_DDDPRINT("nargs=%ld", (long) nargs));

	duk_set_top(thr, 2);
	len = duk__push_this_obj_len_u32(thr);
	duk_require_callable(thr, 0);

	/* stack[0] = callback fn
	 * stack[1] = initialValue
	 * stack[2] = object (coerced this)
	 * stack[3] = length (not needed, but not popped above)
	 * stack[4] = accumulator
	 */

	have_acc = 0;
	if (nargs >= 2) {
		duk_dup_1(thr);
		have_acc = 1;
	}
	DUK_DDD(DUK_DDDPRINT("have_acc=%ld, acc=%!T",
	                     (long) have_acc, (duk_tval *) duk_get_tval(thr, 3)));

	/* For len == 0, i is initialized to len - 1 which underflows.
	 * The condition (i < len) will then exit the for-loop on the
	 * first round which is correct.  Similarly, loop termination
	 * happens by i underflowing.
	 */

	for (i = (idx_step >= 0 ? 0 : len - 1);
	     i < len;  /* i >= 0 would always be true */
	     i += (duk_uint32_t) idx_step) {
		DUK_DDD(DUK_DDDPRINT("i=%ld, len=%ld, have_acc=%ld, top=%ld, acc=%!T",
		                     (long) i, (long) len, (long) have_acc,
		                     (long) duk_get_top(thr),
		                     (duk_tval *) duk_get_tval(thr, 4)));

		DUK_ASSERT((have_acc && duk_get_top(thr) == 5) ||
		           (!have_acc && duk_get_top(thr) == 4));

		if (!duk_has_prop_index(thr, 2, (duk_uarridx_t) i)) {
			continue;
		}

		if (!have_acc) {
			DUK_ASSERT_TOP(thr, 4);
			duk_get_prop_index(thr, 2, (duk_uarridx_t) i);
			have_acc = 1;
			DUK_ASSERT_TOP(thr, 5);
		} else {
			DUK_ASSERT_TOP(thr, 5);
			duk_dup_0(thr);
			duk_dup(thr, 4);
			duk_get_prop_index(thr, 2, (duk_uarridx_t) i);
			duk_push_u32(thr, i);
			duk_dup_2(thr);
			DUK_DDD(DUK_DDDPRINT("calling reduce function: func=%!T, prev=%!T, curr=%!T, idx=%!T, obj=%!T",
			                     (duk_tval *) duk_get_tval(thr, -5), (duk_tval *) duk_get_tval(thr, -4),
			                     (duk_tval *) duk_get_tval(thr, -3), (duk_tval *) duk_get_tval(thr, -2),
			                     (duk_tval *) duk_get_tval(thr, -1)));
			duk_call(thr, 4);
			DUK_DDD(DUK_DDDPRINT("-> result: %!T", (duk_tval *) duk_get_tval(thr, -1)));
			duk_replace(thr, 4);
			DUK_ASSERT_TOP(thr, 5);
		}
	}

	if (!have_acc) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	DUK_ASSERT_TOP(thr, 5);
	return 1;
}

#endif  /* DUK_USE_ARRAY_BUILTIN */

/* automatic undefs */
#undef DUK__ARRAY_MID_JOIN_LIMIT
#undef DUK__ITER_EVERY
#undef DUK__ITER_FILTER
#undef DUK__ITER_FOREACH
#undef DUK__ITER_MAP
#undef DUK__ITER_SOME
/*
 *  Boolean built-ins
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_BOOLEAN_BUILTIN)

/* Shared helper to provide toString() and valueOf().  Checks 'this', gets
 * the primitive value to stack top, and optionally coerces with ToString().
 */
DUK_INTERNAL duk_ret_t duk_bi_boolean_prototype_tostring_shared(duk_hthread *thr) {
	duk_tval *tv;
	duk_hobject *h;
	duk_small_int_t coerce_tostring = duk_get_current_magic(thr);

	/* XXX: there is room to use a shared helper here, many built-ins
	 * check the 'this' type, and if it's an object, check its class,
	 * then get its internal value, etc.
	 */

	duk_push_this(thr);
	tv = duk_get_tval(thr, -1);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_BOOLEAN(tv)) {
		goto type_ok;
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		if (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_BOOLEAN) {
			duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
			DUK_ASSERT(duk_is_boolean(thr, -1));
			goto type_ok;
		}
	}

	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	/* never here */

 type_ok:
	if (coerce_tostring) {
		duk_to_string(thr, -1);
	}
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_boolean_constructor(duk_hthread *thr) {
	duk_hobject *h_this;

	duk_to_boolean(thr, 0);

	if (duk_is_constructor_call(thr)) {
		/* XXX: helper; rely on Boolean.prototype as being non-writable, non-configurable */
		duk_push_this(thr);
		h_this = duk_known_hobject(thr, -1);
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_this) == thr->builtins[DUK_BIDX_BOOLEAN_PROTOTYPE]);

		DUK_HOBJECT_SET_CLASS_NUMBER(h_this, DUK_HOBJECT_CLASS_BOOLEAN);

		duk_dup_0(thr);  /* -> [ val obj val ] */
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);  /* XXX: proper flags? */
	}  /* unbalanced stack */

	return 1;
}

#endif  /* DUK_USE_BOOLEAN_BUILTIN */
/*
 *  ES2015 TypedArray and Node.js Buffer built-ins
 */

/* #include duk_internal.h -> already included */

/*
 *  Helpers for buffer handling, enabled with DUK_USE_BUFFEROBJECT_SUPPORT.
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
/* Map class number (minus DUK_HOBJECT_CLASS_BUFOBJ_MIN) to a bidx for the
 * default internal prototype.
 */
static const duk_uint8_t duk__buffer_proto_from_classnum[] = {
	DUK_BIDX_ARRAYBUFFER_PROTOTYPE,
	DUK_BIDX_DATAVIEW_PROTOTYPE,
	DUK_BIDX_INT8ARRAY_PROTOTYPE,
	DUK_BIDX_UINT8ARRAY_PROTOTYPE,
	DUK_BIDX_UINT8CLAMPEDARRAY_PROTOTYPE,
	DUK_BIDX_INT16ARRAY_PROTOTYPE,
	DUK_BIDX_UINT16ARRAY_PROTOTYPE,
	DUK_BIDX_INT32ARRAY_PROTOTYPE,
	DUK_BIDX_UINT32ARRAY_PROTOTYPE,
	DUK_BIDX_FLOAT32ARRAY_PROTOTYPE,
	DUK_BIDX_FLOAT64ARRAY_PROTOTYPE
};

/* Map DUK_HBUFOBJ_ELEM_xxx to duk_hobject class number.
 * Sync with duk_hbufobj.h and duk_hobject.h.
 */
static const duk_uint8_t duk__buffer_class_from_elemtype[9] = {
	DUK_HOBJECT_CLASS_UINT8ARRAY,
	DUK_HOBJECT_CLASS_UINT8CLAMPEDARRAY,
	DUK_HOBJECT_CLASS_INT8ARRAY,
	DUK_HOBJECT_CLASS_UINT16ARRAY,
	DUK_HOBJECT_CLASS_INT16ARRAY,
	DUK_HOBJECT_CLASS_UINT32ARRAY,
	DUK_HOBJECT_CLASS_INT32ARRAY,
	DUK_HOBJECT_CLASS_FLOAT32ARRAY,
	DUK_HOBJECT_CLASS_FLOAT64ARRAY
};

/* Map DUK_HBUFOBJ_ELEM_xxx to prototype object built-in index.
 * Sync with duk_hbufobj.h.
 */
static const duk_uint8_t duk__buffer_proto_from_elemtype[9] = {
	DUK_BIDX_UINT8ARRAY_PROTOTYPE,
	DUK_BIDX_UINT8CLAMPEDARRAY_PROTOTYPE,
	DUK_BIDX_INT8ARRAY_PROTOTYPE,
	DUK_BIDX_UINT16ARRAY_PROTOTYPE,
	DUK_BIDX_INT16ARRAY_PROTOTYPE,
	DUK_BIDX_UINT32ARRAY_PROTOTYPE,
	DUK_BIDX_INT32ARRAY_PROTOTYPE,
	DUK_BIDX_FLOAT32ARRAY_PROTOTYPE,
	DUK_BIDX_FLOAT64ARRAY_PROTOTYPE
};

/* Map DUK__FLD_xxx to byte size. */
static const duk_uint8_t duk__buffer_nbytes_from_fldtype[6] = {
	1,  /* DUK__FLD_8BIT */
	2,  /* DUK__FLD_16BIT */
	4,  /* DUK__FLD_32BIT */
	4,  /* DUK__FLD_FLOAT */
	8,  /* DUK__FLD_DOUBLE */
	0   /* DUK__FLD_VARINT; not relevant here */
};

/* Bitfield for each DUK_HBUFOBJ_ELEM_xxx indicating which element types
 * are compatible with a blind byte copy for the TypedArray set() method (also
 * used for TypedArray constructor).  Array index is target buffer elem type,
 * bitfield indicates compatible source types.  The types must have same byte
 * size and they must be coercion compatible.
 */
#if !defined(DUK_USE_PREFER_SIZE)
static duk_uint16_t duk__buffer_elemtype_copy_compatible[9] = {
	/* xxx -> DUK_HBUFOBJ_ELEM_UINT8 */
	(1U << DUK_HBUFOBJ_ELEM_UINT8) |
		(1U << DUK_HBUFOBJ_ELEM_UINT8CLAMPED) |
		(1U << DUK_HBUFOBJ_ELEM_INT8),

	/* xxx -> DUK_HBUFOBJ_ELEM_UINT8CLAMPED
	 * Note: INT8 is -not- copy compatible, e.g. -1 would coerce to 0x00.
	 */
	(1U << DUK_HBUFOBJ_ELEM_UINT8) |
		(1U << DUK_HBUFOBJ_ELEM_UINT8CLAMPED),

	/* xxx -> DUK_HBUFOBJ_ELEM_INT8 */
	(1U << DUK_HBUFOBJ_ELEM_UINT8) |
		(1U << DUK_HBUFOBJ_ELEM_UINT8CLAMPED) |
		(1U << DUK_HBUFOBJ_ELEM_INT8),

	/* xxx -> DUK_HBUFOBJ_ELEM_UINT16 */
	(1U << DUK_HBUFOBJ_ELEM_UINT16) |
		(1U << DUK_HBUFOBJ_ELEM_INT16),

	/* xxx -> DUK_HBUFOBJ_ELEM_INT16 */
	(1U << DUK_HBUFOBJ_ELEM_UINT16) |
		(1U << DUK_HBUFOBJ_ELEM_INT16),

	/* xxx -> DUK_HBUFOBJ_ELEM_UINT32 */
	(1U << DUK_HBUFOBJ_ELEM_UINT32) |
		(1U << DUK_HBUFOBJ_ELEM_INT32),

	/* xxx -> DUK_HBUFOBJ_ELEM_INT32 */
	(1U << DUK_HBUFOBJ_ELEM_UINT32) |
		(1U << DUK_HBUFOBJ_ELEM_INT32),

	/* xxx -> DUK_HBUFOBJ_ELEM_FLOAT32 */
	(1U << DUK_HBUFOBJ_ELEM_FLOAT32),

	/* xxx -> DUK_HBUFOBJ_ELEM_FLOAT64 */
	(1U << DUK_HBUFOBJ_ELEM_FLOAT64)
};
#endif  /* !DUK_USE_PREFER_SIZE */

DUK_LOCAL duk_hbufobj *duk__hbufobj_promote_this(duk_hthread *thr) {
	duk_tval *tv_dst;
	duk_hbufobj *res;

	duk_push_this(thr);
	DUK_ASSERT(duk_is_buffer(thr, -1));
	res = (duk_hbufobj *) duk_to_hobject(thr, -1);
	DUK_HBUFOBJ_ASSERT_VALID(res);
	DUK_DD(DUK_DDPRINT("promoted 'this' automatically to an ArrayBuffer: %!iT", duk_get_tval(thr, -1)));

	tv_dst = duk_get_borrowed_this_tval(thr);
	DUK_TVAL_SET_OBJECT_UPDREF(thr, tv_dst, (duk_hobject *) res);
	duk_pop(thr);

	return res;
}

#define DUK__BUFOBJ_FLAG_THROW    (1 << 0)
#define DUK__BUFOBJ_FLAG_PROMOTE  (1 << 1)

/* Shared helper.  When DUK__BUFOBJ_FLAG_PROMOTE is given, the return value is
 * always a duk_hbufobj *.  Without the flag the return value can also be a
 * plain buffer, and the caller must check for it using DUK_HEAPHDR_IS_BUFFER().
 */
DUK_LOCAL duk_heaphdr *duk__getrequire_bufobj_this(duk_hthread *thr, duk_small_uint_t flags) {
	duk_tval *tv;
	duk_hbufobj *h_this;

	DUK_ASSERT(thr != NULL);

	tv = duk_get_borrowed_this_tval(thr);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_OBJECT(tv)) {
		h_this = (duk_hbufobj *) DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h_this != NULL);
		if (DUK_HOBJECT_IS_BUFOBJ((duk_hobject *) h_this)) {
			DUK_HBUFOBJ_ASSERT_VALID(h_this);
			return (duk_heaphdr *) h_this;
		}
	} else if (DUK_TVAL_IS_BUFFER(tv)) {
		if (flags & DUK__BUFOBJ_FLAG_PROMOTE) {
			/* Promote a plain buffer to a Uint8Array.  This is very
			 * inefficient but allows plain buffer to be used wherever an
			 * Uint8Array is used with very small cost; hot path functions
			 * like index read/write calls should provide direct buffer
			 * support to avoid promotion.
			 */
			/* XXX: make this conditional to a flag if call sites need it? */
			h_this = duk__hbufobj_promote_this(thr);
			DUK_ASSERT(h_this != NULL);
			DUK_HBUFOBJ_ASSERT_VALID(h_this);
			return (duk_heaphdr *) h_this;
		} else {
			/* XXX: ugly, share return pointer for duk_hbuffer. */
			return (duk_heaphdr *) DUK_TVAL_GET_BUFFER(tv);
		}
	}

	if (flags & DUK__BUFOBJ_FLAG_THROW) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_BUFFER);
		DUK_WO_NORETURN(return NULL;);
	}
	return NULL;
}

/* Check that 'this' is a duk_hbufobj and return a pointer to it. */
DUK_LOCAL duk_hbufobj *duk__get_bufobj_this(duk_hthread *thr) {
	return (duk_hbufobj *) duk__getrequire_bufobj_this(thr, DUK__BUFOBJ_FLAG_PROMOTE);
}

/* Check that 'this' is a duk_hbufobj and return a pointer to it
 * (NULL if not).
 */
DUK_LOCAL duk_hbufobj *duk__require_bufobj_this(duk_hthread *thr) {
	return (duk_hbufobj *) duk__getrequire_bufobj_this(thr, DUK__BUFOBJ_FLAG_THROW | DUK__BUFOBJ_FLAG_PROMOTE);
}

/* Check that value is a duk_hbufobj and return a pointer to it. */
DUK_LOCAL duk_hbufobj *duk__require_bufobj_value(duk_hthread *thr, duk_idx_t idx) {
	duk_tval *tv;
	duk_hbufobj *h_obj;

	/* Don't accept relative indices now. */
	DUK_ASSERT(idx >= 0);

	tv = duk_require_tval(thr, idx);
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		h_obj = (duk_hbufobj *) DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h_obj != NULL);
		if (DUK_HOBJECT_IS_BUFOBJ((duk_hobject *) h_obj)) {
			DUK_HBUFOBJ_ASSERT_VALID(h_obj);
			return h_obj;
		}
	} else if (DUK_TVAL_IS_BUFFER(tv)) {
		h_obj = (duk_hbufobj *) duk_to_hobject(thr, idx);
		DUK_ASSERT(h_obj != NULL);
		DUK_HBUFOBJ_ASSERT_VALID(h_obj);
		return h_obj;
	}

	DUK_ERROR_TYPE(thr, DUK_STR_NOT_BUFFER);
	DUK_WO_NORETURN(return NULL;);
}

DUK_LOCAL void duk__set_bufobj_buffer(duk_hthread *thr, duk_hbufobj *h_bufobj, duk_hbuffer *h_val) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h_bufobj != NULL);
	DUK_ASSERT(h_bufobj->buf == NULL);  /* no need to decref */
	DUK_ASSERT(h_val != NULL);
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
	DUK_UNREF(thr);

	h_bufobj->buf = h_val;
	DUK_HBUFFER_INCREF(thr, h_val);
	h_bufobj->length = (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_val);
	DUK_ASSERT(h_bufobj->shift == 0);
	DUK_ASSERT(h_bufobj->elem_type == DUK_HBUFOBJ_ELEM_UINT8);
	DUK_ASSERT(h_bufobj->is_typedarray == 0);

	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
}

/* Shared offset/length coercion helper. */
DUK_LOCAL void duk__resolve_offset_opt_length(duk_hthread *thr,
                                              duk_hbufobj *h_bufarg,
                                              duk_idx_t idx_offset,
                                              duk_idx_t idx_length,
                                              duk_uint_t *out_offset,
                                              duk_uint_t *out_length,
                                              duk_bool_t throw_flag) {
	duk_int_t offset_signed;
	duk_int_t length_signed;
	duk_uint_t offset;
	duk_uint_t length;

	offset_signed = duk_to_int(thr, idx_offset);
	if (offset_signed < 0) {
		goto fail_range;
	}
	offset = (duk_uint_t) offset_signed;
	if (offset > h_bufarg->length) {
		goto fail_range;
	}
	DUK_ASSERT_DISABLE(offset >= 0);  /* unsigned */
	DUK_ASSERT(offset <= h_bufarg->length);

	if (duk_is_undefined(thr, idx_length)) {
		DUK_ASSERT(h_bufarg->length >= offset);
		length = h_bufarg->length - offset;  /* >= 0 */
	} else {
		length_signed = duk_to_int(thr, idx_length);
		if (length_signed < 0) {
			goto fail_range;
		}
		length = (duk_uint_t) length_signed;
		DUK_ASSERT(h_bufarg->length >= offset);
		if (length > h_bufarg->length - offset) {
			/* Unlike for negative arguments, some call sites
			 * want length to be clamped if it's positive.
			 */
			if (throw_flag) {
				goto fail_range;
			} else {
				length = h_bufarg->length - offset;
			}
		}
	}
	DUK_ASSERT_DISABLE(length >= 0);  /* unsigned */
	DUK_ASSERT(offset + length <= h_bufarg->length);

	*out_offset = offset;
	*out_length = length;
	return;

 fail_range:
	DUK_ERROR_RANGE(thr, DUK_STR_INVALID_ARGS);
	DUK_WO_NORETURN(return;);
}

/* Shared lenient buffer length clamping helper.  No negative indices, no
 * element/byte shifting.
 */
DUK_LOCAL void duk__clamp_startend_nonegidx_noshift(duk_hthread *thr,
                                                    duk_int_t buffer_length,
                                                    duk_idx_t idx_start,
                                                    duk_idx_t idx_end,
                                                    duk_int_t *out_start_offset,
                                                    duk_int_t *out_end_offset) {
	duk_int_t start_offset;
	duk_int_t end_offset;

	DUK_ASSERT(out_start_offset != NULL);
	DUK_ASSERT(out_end_offset != NULL);

	/* undefined coerces to zero which is correct */
	start_offset = duk_to_int_clamped(thr, idx_start, 0, buffer_length);
	if (duk_is_undefined(thr, idx_end)) {
		end_offset = buffer_length;
	} else {
		end_offset = duk_to_int_clamped(thr, idx_end, start_offset, buffer_length);
	}

	DUK_ASSERT(start_offset >= 0);
	DUK_ASSERT(start_offset <= buffer_length);
	DUK_ASSERT(end_offset >= 0);
	DUK_ASSERT(end_offset <= buffer_length);
	DUK_ASSERT(start_offset <= end_offset);

	*out_start_offset = start_offset;
	*out_end_offset = end_offset;
}

/* Shared lenient buffer length clamping helper.  Indices are treated as
 * element indices (though output values are byte offsets) which only
 * really matters for TypedArray views as other buffer object have a zero
 * shift.  Negative indices are counted from end of input slice; crossed
 * indices are clamped to zero length; and final indices are clamped
 * against input slice.  Used for e.g. ArrayBuffer slice().
 */
DUK_LOCAL void duk__clamp_startend_negidx_shifted(duk_hthread *thr,
                                                  duk_int_t buffer_length,
                                                  duk_uint8_t buffer_shift,
                                                  duk_idx_t idx_start,
                                                  duk_idx_t idx_end,
                                                  duk_int_t *out_start_offset,
                                                  duk_int_t *out_end_offset) {
	duk_int_t start_offset;
	duk_int_t end_offset;

	DUK_ASSERT(out_start_offset != NULL);
	DUK_ASSERT(out_end_offset != NULL);

	buffer_length >>= buffer_shift;  /* as (full) elements */

	/* Resolve start/end offset as element indices first; arguments
	 * at idx_start/idx_end are element offsets.  Working with element
	 * indices first also avoids potential for wrapping.
	 */

	start_offset = duk_to_int(thr, idx_start);
	if (start_offset < 0) {
		start_offset = buffer_length + start_offset;
	}
	if (duk_is_undefined(thr, idx_end)) {
		end_offset = buffer_length;
	} else {
		end_offset = duk_to_int(thr, idx_end);
		if (end_offset < 0) {
			end_offset = buffer_length + end_offset;
		}
	}
	/* Note: start_offset/end_offset can still be < 0 here. */

	if (start_offset < 0) {
		start_offset = 0;
	} else if (start_offset > buffer_length) {
		start_offset = buffer_length;
	}
	if (end_offset < start_offset) {
		end_offset = start_offset;
	} else if (end_offset > buffer_length) {
		end_offset = buffer_length;
	}
	DUK_ASSERT(start_offset >= 0);
	DUK_ASSERT(start_offset <= buffer_length);
	DUK_ASSERT(end_offset >= 0);
	DUK_ASSERT(end_offset <= buffer_length);
	DUK_ASSERT(start_offset <= end_offset);

	/* Convert indices to byte offsets. */
	start_offset <<= buffer_shift;
	end_offset <<= buffer_shift;

	*out_start_offset = start_offset;
	*out_end_offset = end_offset;
}

DUK_INTERNAL void duk_hbufobj_promote_plain(duk_hthread *thr, duk_idx_t idx) {
	if (duk_is_buffer(thr, idx)) {
		duk_to_object(thr, idx);
	}
}

DUK_INTERNAL void duk_hbufobj_push_uint8array_from_plain(duk_hthread *thr, duk_hbuffer *h_buf) {
	/* Push Uint8Array which will share the same underlying buffer as
	 * the plain buffer argument.  Also create an ArrayBuffer with the
	 * same backing for the result .buffer property.
	 */

	duk_push_hbuffer(thr, h_buf);
	duk_push_buffer_object(thr, -1, 0, (duk_size_t) DUK_HBUFFER_GET_SIZE(h_buf), DUK_BUFOBJ_UINT8ARRAY);
	duk_remove_m2(thr);

#if 0
	/* More verbose equivalent; maybe useful if e.g. .buffer is omitted. */
	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_UINT8ARRAY),
	                               DUK_BIDX_UINT8ARRAY_PROTOTYPE);
	DUK_ASSERT(h_bufobj != NULL);
	duk__set_bufobj_buffer(thr, h_bufobj, h_buf);
	h_bufobj->is_typedarray = 1;
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

	h_arrbuf = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARRAYBUFFER),
	                               DUK_BIDX_ARRAYBUFFER_PROTOTYPE);
	DUK_ASSERT(h_arrbuf != NULL);
	duk__set_bufobj_buffer(thr, h_arrbuf, h_buf);
	DUK_ASSERT(h_arrbuf->is_typedarray == 0);
	DUK_HBUFOBJ_ASSERT_VALID(h_arrbuf);

	DUK_ASSERT(h_bufobj->buf_prop == NULL);
	h_bufobj->buf_prop = (duk_hobject *) h_arrbuf;
	DUK_ASSERT(h_arrbuf != NULL);
	DUK_HBUFOBJ_INCREF(thr, h_arrbuf);
	duk_pop(thr);
#endif
}

/* Indexed read helper for buffer objects, also called from outside this file. */
DUK_INTERNAL void duk_hbufobj_push_validated_read(duk_hthread *thr, duk_hbufobj *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size) {
	duk_double_union du;

	DUK_ASSERT(elem_size > 0);
	duk_memcpy((void *) du.uc, (const void *) p, (size_t) elem_size);

	switch (h_bufobj->elem_type) {
	case DUK_HBUFOBJ_ELEM_UINT8:
	case DUK_HBUFOBJ_ELEM_UINT8CLAMPED:
		duk_push_uint(thr, (duk_uint_t) du.uc[0]);
		break;
	case DUK_HBUFOBJ_ELEM_INT8:
		duk_push_int(thr, (duk_int_t) (duk_int8_t) du.uc[0]);
		break;
	case DUK_HBUFOBJ_ELEM_UINT16:
		duk_push_uint(thr, (duk_uint_t) du.us[0]);
		break;
	case DUK_HBUFOBJ_ELEM_INT16:
		duk_push_int(thr, (duk_int_t) (duk_int16_t) du.us[0]);
		break;
	case DUK_HBUFOBJ_ELEM_UINT32:
		duk_push_uint(thr, (duk_uint_t) du.ui[0]);
		break;
	case DUK_HBUFOBJ_ELEM_INT32:
		duk_push_int(thr, (duk_int_t) (duk_int32_t) du.ui[0]);
		break;
	case DUK_HBUFOBJ_ELEM_FLOAT32:
		duk_push_number(thr, (duk_double_t) du.f[0]);
		break;
	case DUK_HBUFOBJ_ELEM_FLOAT64:
		duk_push_number(thr, (duk_double_t) du.d);
		break;
	default:
		DUK_UNREACHABLE();
	}
}

/* Indexed write helper for buffer objects, also called from outside this file. */
DUK_INTERNAL void duk_hbufobj_validated_write(duk_hthread *thr, duk_hbufobj *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size) {
	duk_double_union du;

	/* NOTE! Caller must ensure that any side effects from the
	 * coercions below are safe.  If that cannot be guaranteed
	 * (which is normally the case), caller must coerce the
	 * argument using duk_to_number() before any pointer
	 * validations; the result of duk_to_number() always coerces
	 * without side effects here.
	 */

	switch (h_bufobj->elem_type) {
	case DUK_HBUFOBJ_ELEM_UINT8:
		du.uc[0] = (duk_uint8_t) duk_to_uint32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_UINT8CLAMPED:
		du.uc[0] = (duk_uint8_t) duk_to_uint8clamped(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_INT8:
		du.uc[0] = (duk_uint8_t) duk_to_int32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_UINT16:
		du.us[0] = (duk_uint16_t) duk_to_uint32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_INT16:
		du.us[0] = (duk_uint16_t) duk_to_int32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_UINT32:
		du.ui[0] = (duk_uint32_t) duk_to_uint32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_INT32:
		du.ui[0] = (duk_uint32_t) duk_to_int32(thr, -1);
		break;
	case DUK_HBUFOBJ_ELEM_FLOAT32:
		/* A double-to-float cast is undefined behavior in C99 if
		 * the cast is out-of-range, so use a helper.  Example:
		 * runtime error: value -1e+100 is outside the range of representable values of type 'float'
		 */
		du.f[0] = duk_double_to_float_t(duk_to_number_m1(thr));
		break;
	case DUK_HBUFOBJ_ELEM_FLOAT64:
		du.d = (duk_double_t) duk_to_number_m1(thr);
		break;
	default:
		DUK_UNREACHABLE();
	}

	DUK_ASSERT(elem_size > 0);
	duk_memcpy((void *) p, (const void *) du.uc, (size_t) elem_size);
}

/* Helper to create a fixed buffer from argument value at index 0.
 * Node.js and allocPlain() compatible.
 */
DUK_LOCAL duk_hbuffer *duk__hbufobj_fixed_from_argvalue(duk_hthread *thr) {
	duk_int_t len;
	duk_int_t i;
	duk_size_t buf_size;
	duk_uint8_t *buf;

	switch (duk_get_type(thr, 0)) {
	case DUK_TYPE_NUMBER: {
		len = duk_to_int_clamped(thr, 0, 0, DUK_INT_MAX);
		(void) duk_push_fixed_buffer_zero(thr, (duk_size_t) len);
		break;
	}
	case DUK_TYPE_BUFFER: { /* Treat like Uint8Array. */
		goto slow_copy;
	}
	case DUK_TYPE_OBJECT: {
		duk_hobject *h;
		duk_hbufobj *h_bufobj;

		/* For Node.js Buffers "Passing an ArrayBuffer returns a Buffer
		 * that shares allocated memory with the given ArrayBuffer."
		 * https://nodejs.org/api/buffer.html#buffer_buffer_from_buffer_alloc_and_buffer_allocunsafe
		 */

		h = duk_known_hobject(thr, 0);
		if (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_ARRAYBUFFER) {
			DUK_ASSERT(DUK_HOBJECT_IS_BUFOBJ(h));
			h_bufobj = (duk_hbufobj *) h;
			if (DUK_UNLIKELY(h_bufobj->buf == NULL)) {
				DUK_ERROR_TYPE_INVALID_ARGS(thr);
				DUK_WO_NORETURN(return NULL;);
			}
			if (DUK_UNLIKELY(h_bufobj->offset != 0 || h_bufobj->length != DUK_HBUFFER_GET_SIZE(h_bufobj->buf))) {
				/* No support for ArrayBuffers with slice
				 * offset/length.
				 */
				DUK_ERROR_TYPE_INVALID_ARGS(thr);
				DUK_WO_NORETURN(return NULL;);
			}
			duk_push_hbuffer(thr, h_bufobj->buf);
			return h_bufobj->buf;
		}
		goto slow_copy;
	}
	case DUK_TYPE_STRING: {
		/* ignore encoding for now */
		duk_require_hstring_notsymbol(thr, 0);
		duk_dup_0(thr);
		(void) duk_to_buffer(thr, -1, &buf_size);
		break;
	}
	default:
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return NULL;);
	}

 done:
	DUK_ASSERT(duk_is_buffer(thr, -1));
	return duk_known_hbuffer(thr, -1);

 slow_copy:
	/* XXX: fast path for typed arrays and other buffer objects? */

	(void) duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_LENGTH);
	len = duk_to_int_clamped(thr, -1, 0, DUK_INT_MAX);
	duk_pop(thr);
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, (duk_size_t) len);  /* no zeroing, all indices get initialized */
	for (i = 0; i < len; i++) {
		/* XXX: fast path for array or buffer arguments? */
		duk_get_prop_index(thr, 0, (duk_uarridx_t) i);
		buf[i] = (duk_uint8_t) (duk_to_uint32(thr, -1) & 0xffU);
		duk_pop(thr);
	}
	goto done;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer constructor
 *
 *  Node.js Buffers are just Uint8Arrays with internal prototype set to
 *  Buffer.prototype so they're handled otherwise the same as Uint8Array.
 *  However, the constructor arguments are very different so a separate
 *  constructor entry point is used.
 */
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_constructor(duk_hthread *thr) {
	duk_hbuffer *h_buf;

	h_buf = duk__hbufobj_fixed_from_argvalue(thr);
	DUK_ASSERT(h_buf != NULL);

	duk_push_buffer_object(thr,
	                       -1,
	                       0,
	                       DUK_HBUFFER_FIXED_GET_SIZE((duk_hbuffer_fixed *) (void *) h_buf),
	                       DUK_BUFOBJ_UINT8ARRAY);
	duk_push_hobject_bidx(thr, DUK_BIDX_NODEJS_BUFFER_PROTOTYPE);
	duk_set_prototype(thr, -2);

	/* XXX: a more direct implementation */

	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  ArrayBuffer, DataView, and TypedArray constructors
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_arraybuffer_constructor(duk_hthread *thr) {
	duk_hbufobj *h_bufobj;
	duk_hbuffer *h_val;
	duk_int_t len;

	DUK_CTX_ASSERT_VALID(thr);

	duk_require_constructor_call(thr);

	len = duk_to_int(thr, 0);
	if (len < 0) {
		goto fail_length;
	}
	(void) duk_push_fixed_buffer_zero(thr, (duk_size_t) len);
	h_val = (duk_hbuffer *) duk_known_hbuffer(thr, -1);

	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARRAYBUFFER),
	                               DUK_BIDX_ARRAYBUFFER_PROTOTYPE);
	DUK_ASSERT(h_bufobj != NULL);

	duk__set_bufobj_buffer(thr, h_bufobj, h_val);
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

	return 1;

 fail_length:
	DUK_DCERROR_RANGE_INVALID_LENGTH(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */


/* Format of magic, bits:
 *   0...1: elem size shift (0-3)
 *   2...5: elem type (DUK_HBUFOBJ_ELEM_xxx)
 *
 * XXX: add prototype bidx explicitly to magic instead of using a mapping?
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_typedarray_constructor(duk_hthread *thr) {
	duk_tval *tv;
	duk_hobject *h_obj;
	duk_hbufobj *h_bufobj = NULL;
	duk_hbufobj *h_bufarg = NULL;
	duk_hbuffer *h_val;
	duk_small_uint_t magic;
	duk_small_uint_t shift;
	duk_small_uint_t elem_type;
	duk_small_uint_t elem_size;
	duk_small_uint_t class_num;
	duk_small_uint_t proto_bidx;
	duk_uint_t align_mask;
	duk_uint_t elem_length;
	duk_int_t elem_length_signed;
	duk_uint_t byte_length;
	duk_small_uint_t copy_mode;

	/* XXX: The same copy helpers could be shared with at least some
	 * buffer functions.
	 */

	duk_require_constructor_call(thr);

	/* We could fit built-in index into magic but that'd make the magic
	 * number dependent on built-in numbering (genbuiltins.py doesn't
	 * handle that yet).  So map both class and prototype from the
	 * element type.
	 */
	magic = (duk_small_uint_t) duk_get_current_magic(thr);
	shift = magic & 0x03U;               /* bits 0...1: shift */
	elem_type = (magic >> 2) & 0x0fU;    /* bits 2...5: type */
	elem_size = 1U << shift;
	align_mask = elem_size - 1;
	DUK_ASSERT(elem_type < sizeof(duk__buffer_proto_from_elemtype) / sizeof(duk_uint8_t));
	proto_bidx = duk__buffer_proto_from_elemtype[elem_type];
	DUK_ASSERT(proto_bidx < DUK_NUM_BUILTINS);
	DUK_ASSERT(elem_type < sizeof(duk__buffer_class_from_elemtype) / sizeof(duk_uint8_t));
	class_num = duk__buffer_class_from_elemtype[elem_type];

	DUK_DD(DUK_DDPRINT("typedarray constructor, magic=%d, shift=%d, elem_type=%d, "
	                   "elem_size=%d, proto_bidx=%d, class_num=%d",
	                   (int) magic, (int) shift, (int) elem_type, (int) elem_size,
	                   (int) proto_bidx, (int) class_num));

	/* Argument variants.  When the argument is an ArrayBuffer a view to
	 * the same buffer is created; otherwise a new ArrayBuffer is always
	 * created.
	 */

	/* XXX: initial iteration to treat a plain buffer like an ArrayBuffer:
	 * coerce to an ArrayBuffer object and use that as .buffer.  The underlying
	 * buffer will be the same but result .buffer !== inputPlainBuffer.
	 */
	duk_hbufobj_promote_plain(thr, 0);

	tv = duk_get_tval(thr, 0);
	DUK_ASSERT(tv != NULL);  /* arg count */
	if (DUK_TVAL_IS_OBJECT(tv)) {
		h_obj = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h_obj != NULL);

		if (DUK_HOBJECT_GET_CLASS_NUMBER(h_obj) == DUK_HOBJECT_CLASS_ARRAYBUFFER) {
			/* ArrayBuffer: unlike any other argument variant, create
			 * a view into the existing buffer.
			 */

			duk_int_t byte_offset_signed;
			duk_uint_t byte_offset;

			h_bufarg = (duk_hbufobj *) h_obj;

			byte_offset_signed = duk_to_int(thr, 1);
			if (byte_offset_signed < 0) {
				goto fail_arguments;
			}
			byte_offset = (duk_uint_t) byte_offset_signed;
			if (byte_offset > h_bufarg->length ||
			    (byte_offset & align_mask) != 0) {
				/* Must be >= 0 and multiple of element size. */
				goto fail_arguments;
			}
			if (duk_is_undefined(thr, 2)) {
				DUK_ASSERT(h_bufarg->length >= byte_offset);
				byte_length = h_bufarg->length - byte_offset;
				if ((byte_length & align_mask) != 0) {
					/* Must be element size multiple from
					 * start offset to end of buffer.
					 */
					goto fail_arguments;
				}
				elem_length = (byte_length >> shift);
			} else {
				elem_length_signed = duk_to_int(thr, 2);
				if (elem_length_signed < 0) {
					goto fail_arguments;
				}
				elem_length = (duk_uint_t) elem_length_signed;
				byte_length = elem_length << shift;
				if ((byte_length >> shift) != elem_length) {
					/* Byte length would overflow. */
					/* XXX: easier check with less code? */
					goto fail_arguments;
				}
				DUK_ASSERT(h_bufarg->length >= byte_offset);
				if (byte_length > h_bufarg->length - byte_offset) {
					/* Not enough data. */
					goto fail_arguments;
				}
			}
			DUK_UNREF(elem_length);
			DUK_ASSERT_DISABLE(byte_offset >= 0);
			DUK_ASSERT(byte_offset <= h_bufarg->length);
			DUK_ASSERT_DISABLE(byte_length >= 0);
			DUK_ASSERT(byte_offset + byte_length <= h_bufarg->length);
			DUK_ASSERT((elem_length << shift) == byte_length);

			h_bufobj = duk_push_bufobj_raw(thr,
			                               DUK_HOBJECT_FLAG_EXTENSIBLE |
			                               DUK_HOBJECT_FLAG_BUFOBJ |
			                               DUK_HOBJECT_CLASS_AS_FLAGS(class_num),
			                               (duk_small_int_t) proto_bidx);
			h_val = h_bufarg->buf;
			if (h_val == NULL) {
				DUK_DCERROR_TYPE_INVALID_ARGS(thr);
			}
			h_bufobj->buf = h_val;
			DUK_HBUFFER_INCREF(thr, h_val);
			h_bufobj->offset = h_bufarg->offset + byte_offset;
			h_bufobj->length = byte_length;
			h_bufobj->shift = (duk_uint8_t) shift;
			h_bufobj->elem_type = (duk_uint8_t) elem_type;
			h_bufobj->is_typedarray = 1;
			DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

			/* Set .buffer to the argument ArrayBuffer. */
			DUK_ASSERT(h_bufobj->buf_prop == NULL);
			h_bufobj->buf_prop = (duk_hobject *) h_bufarg;
			DUK_ASSERT(h_bufarg != NULL);
			DUK_HBUFOBJ_INCREF(thr, h_bufarg);
			return 1;
		} else if (DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
			/* TypedArray (or other non-ArrayBuffer duk_hbufobj).
			 * Conceptually same behavior as for an Array-like argument,
			 * with a few fast paths.
			 */

			h_bufarg = (duk_hbufobj *) h_obj;
			DUK_HBUFOBJ_ASSERT_VALID(h_bufarg);
			elem_length_signed = (duk_int_t) (h_bufarg->length >> h_bufarg->shift);
			if (h_bufarg->buf == NULL) {
				DUK_DCERROR_TYPE_INVALID_ARGS(thr);
			}

			/* Select copy mode.  Must take into account element
			 * compatibility and validity of the underlying source
			 * buffer.
			 */

			DUK_DDD(DUK_DDDPRINT("selecting copy mode for bufobj arg, "
			                     "src byte_length=%ld, src shift=%d, "
			                     "src/dst elem_length=%ld; "
			                     "dst shift=%d -> dst byte_length=%ld",
			                     (long) h_bufarg->length, (int) h_bufarg->shift,
			                     (long) elem_length_signed, (int) shift,
			                     (long) (elem_length_signed << shift)));

			copy_mode = 2;  /* default is explicit index read/write copy */
#if !defined(DUK_USE_PREFER_SIZE)
			/* With a size optimized build copy_mode 2 is enough.
			 * Modes 0 and 1 are faster but conceptually the same.
			 */
			DUK_ASSERT(elem_type < sizeof(duk__buffer_elemtype_copy_compatible) / sizeof(duk_uint16_t));
			if (DUK_HBUFOBJ_VALID_SLICE(h_bufarg)) {
				if ((duk__buffer_elemtype_copy_compatible[elem_type] & (1 << h_bufarg->elem_type)) != 0) {
					DUK_DDD(DUK_DDDPRINT("source/target are copy compatible, memcpy"));
					DUK_ASSERT(shift == h_bufarg->shift);  /* byte sizes will match */
					copy_mode = 0;
				} else {
					DUK_DDD(DUK_DDDPRINT("source/target not copy compatible but valid, fast copy"));
					copy_mode = 1;
				}
			}
#endif  /* !DUK_USE_PREFER_SIZE */
		} else {
			/* Array or Array-like */
			elem_length_signed = (duk_int_t) duk_get_length(thr, 0);
			copy_mode = 2;
		}
	} else {
		/* Non-object argument is simply int coerced, matches
		 * V8 behavior (except for "null", which we coerce to
		 * 0 but V8 TypeErrors).
		 */
		elem_length_signed = duk_to_int(thr, 0);
		copy_mode = 3;
	}
	if (elem_length_signed < 0) {
		goto fail_arguments;
	}
	elem_length = (duk_uint_t) elem_length_signed;
	byte_length = (duk_uint_t) (elem_length << shift);
	if ((byte_length >> shift) != elem_length) {
		/* Byte length would overflow. */
		/* XXX: easier check with less code? */
		goto fail_arguments;
	}

	DUK_DDD(DUK_DDDPRINT("elem_length=%ld, byte_length=%ld",
	                     (long) elem_length, (long) byte_length));

	/* ArrayBuffer argument is handled specially above; the rest of the
	 * argument variants are handled by shared code below.
	 *
	 * ArrayBuffer in h_bufobj->buf_prop is intentionally left unset.
	 * It will be automatically created by the .buffer accessor on
	 * first access.
	 */

	/* Push the resulting view object on top of a plain fixed buffer. */
	(void) duk_push_fixed_buffer(thr, byte_length);
	h_val = duk_known_hbuffer(thr, -1);
	DUK_ASSERT(h_val != NULL);

	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(class_num),
	                               (duk_small_int_t) proto_bidx);

	h_bufobj->buf = h_val;
	DUK_HBUFFER_INCREF(thr, h_val);
	DUK_ASSERT(h_bufobj->offset == 0);
	h_bufobj->length = byte_length;
	h_bufobj->shift = (duk_uint8_t) shift;
	h_bufobj->elem_type = (duk_uint8_t) elem_type;
	h_bufobj->is_typedarray = 1;
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

	/* Copy values, the copy method depends on the arguments.
	 *
	 * Copy mode decision may depend on the validity of the underlying
	 * buffer of the source argument; there must be no harmful side effects
	 * from there to here for copy_mode to still be valid.
	 */
	DUK_DDD(DUK_DDDPRINT("copy mode: %d", (int) copy_mode));
	switch (copy_mode) {
		/* Copy modes 0 and 1 can be omitted in size optimized build,
		 * copy mode 2 handles them (but more slowly).
		 */
#if !defined(DUK_USE_PREFER_SIZE)
	case 0: {
		/* Use byte copy. */

		duk_uint8_t *p_src;
		duk_uint8_t *p_dst;

		DUK_ASSERT(h_bufobj != NULL);
		DUK_ASSERT(h_bufobj->buf != NULL);
		DUK_ASSERT(DUK_HBUFOBJ_VALID_SLICE(h_bufobj));
		DUK_ASSERT(h_bufarg != NULL);
		DUK_ASSERT(h_bufarg->buf != NULL);
		DUK_ASSERT(DUK_HBUFOBJ_VALID_SLICE(h_bufarg));

		p_dst = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufobj);
		p_src = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufarg);

		DUK_DDD(DUK_DDDPRINT("using memcpy: p_src=%p, p_dst=%p, byte_length=%ld",
		                     (void *) p_src, (void *) p_dst, (long) byte_length));

		duk_memcpy_unsafe((void *) p_dst, (const void *) p_src, (size_t) byte_length);
		break;
	}
	case 1: {
		/* Copy values through direct validated reads and writes. */

		duk_small_uint_t src_elem_size;
		duk_small_uint_t dst_elem_size;
		duk_uint8_t *p_src;
		duk_uint8_t *p_src_end;
		duk_uint8_t *p_dst;

		DUK_ASSERT(h_bufobj != NULL);
		DUK_ASSERT(h_bufobj->buf != NULL);
		DUK_ASSERT(DUK_HBUFOBJ_VALID_SLICE(h_bufobj));
		DUK_ASSERT(h_bufarg != NULL);
		DUK_ASSERT(h_bufarg->buf != NULL);
		DUK_ASSERT(DUK_HBUFOBJ_VALID_SLICE(h_bufarg));

		src_elem_size = (duk_small_uint_t) (1U << h_bufarg->shift);
		dst_elem_size = elem_size;

		p_src = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufarg);
		p_dst = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufobj);
		p_src_end = p_src + h_bufarg->length;

		DUK_DDD(DUK_DDDPRINT("using fast copy: p_src=%p, p_src_end=%p, p_dst=%p, "
		                     "src_elem_size=%d, dst_elem_size=%d",
		                     (void *) p_src, (void *) p_src_end, (void *) p_dst,
		                     (int) src_elem_size, (int) dst_elem_size));

		while (p_src != p_src_end) {
			DUK_DDD(DUK_DDDPRINT("fast path per element copy loop: "
			                     "p_src=%p, p_src_end=%p, p_dst=%p",
			                     (void *) p_src, (void *) p_src_end, (void *) p_dst));
			/* A validated read() is always a number, so it's write coercion
			 * is always side effect free an won't invalidate pointers etc.
			 */
			duk_hbufobj_push_validated_read(thr, h_bufarg, p_src, src_elem_size);
			duk_hbufobj_validated_write(thr, h_bufobj, p_dst, dst_elem_size);
			duk_pop(thr);
			p_src += src_elem_size;
			p_dst += dst_elem_size;
		}
		break;
	}
#endif  /* !DUK_USE_PREFER_SIZE */
	case 2: {
		/* Copy values by index reads and writes.  Let virtual
		 * property handling take care of coercion.
		 */
		duk_uint_t i;

		DUK_DDD(DUK_DDDPRINT("using slow copy"));

		for (i = 0; i < elem_length; i++) {
			duk_get_prop_index(thr, 0, (duk_uarridx_t) i);
			duk_put_prop_index(thr, -2, (duk_uarridx_t) i);
		}
		break;
	}
	default:
	case 3: {
		/* No copy, leave zero bytes in the buffer.  There's no
		 * ambiguity with Float32/Float64 because zero bytes also
		 * represent 0.0.
		 */

		DUK_DDD(DUK_DDDPRINT("using no copy"));
		break;
	}
	}

	return 1;

 fail_arguments:
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#else  /* DUK_USE_BUFFEROBJECT_SUPPORT */
/* When bufferobject support is disabled, new Uint8Array() could still be
 * supported to create a plain fixed buffer.  Disabled for now.
 */
#if 0
DUK_INTERNAL duk_ret_t duk_bi_typedarray_constructor(duk_hthread *thr) {
	duk_int_t elem_length_signed;
	duk_uint_t byte_length;

	/* XXX: The same copy helpers could be shared with at least some
	 * buffer functions.
	 */

	duk_require_constructor_call(thr);

	elem_length_signed = duk_require_int(thr, 0);
	if (elem_length_signed < 0) {
		goto fail_arguments;
	}
	byte_length = (duk_uint_t) elem_length_signed;

	(void) duk_push_fixed_buffer_zero(thr, (duk_size_t) byte_length);
	return 1;

 fail_arguments:
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* 0 */
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_dataview_constructor(duk_hthread *thr) {
	duk_hbufobj *h_bufarg;
	duk_hbufobj *h_bufobj;
	duk_hbuffer *h_val;
	duk_uint_t offset;
	duk_uint_t length;

	duk_require_constructor_call(thr);

	h_bufarg = duk__require_bufobj_value(thr, 0);
	DUK_ASSERT(h_bufarg != NULL);
	if (DUK_HOBJECT_GET_CLASS_NUMBER((duk_hobject *) h_bufarg) != DUK_HOBJECT_CLASS_ARRAYBUFFER) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	duk__resolve_offset_opt_length(thr, h_bufarg, 1, 2, &offset, &length, 1 /*throw_flag*/);
	DUK_ASSERT(offset <= h_bufarg->length);
	DUK_ASSERT(offset + length <= h_bufarg->length);

	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DATAVIEW),
	                               DUK_BIDX_DATAVIEW_PROTOTYPE);

	h_val = h_bufarg->buf;
	if (h_val == NULL) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}
	h_bufobj->buf = h_val;
	DUK_HBUFFER_INCREF(thr, h_val);
	h_bufobj->offset = h_bufarg->offset + offset;
	h_bufobj->length = length;
	DUK_ASSERT(h_bufobj->shift == 0);
	DUK_ASSERT(h_bufobj->elem_type == DUK_HBUFOBJ_ELEM_UINT8);
	DUK_ASSERT(h_bufobj->is_typedarray == 0);

	DUK_ASSERT(h_bufobj->buf_prop == NULL);
	h_bufobj->buf_prop = (duk_hobject *) h_bufarg;
	DUK_ASSERT(h_bufarg != NULL);
	DUK_HBUFOBJ_INCREF(thr, h_bufarg);

	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  ArrayBuffer.isView()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_arraybuffer_isview(duk_hthread *thr) {
	duk_hobject *h_obj;
	duk_bool_t ret = 0;

	if (duk_is_buffer(thr, 0)) {
		ret = 1;
	} else {
		h_obj = duk_get_hobject(thr, 0);
		if (h_obj != NULL && DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
			/* DataView needs special casing: ArrayBuffer.isView() is
			 * true, but ->is_typedarray is 0.
			 */
			ret = ((duk_hbufobj *) h_obj)->is_typedarray ||
			      (DUK_HOBJECT_GET_CLASS_NUMBER(h_obj) == DUK_HOBJECT_CLASS_DATAVIEW);
		}
	}
	duk_push_boolean(thr, ret);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Uint8Array.allocPlain()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_uint8array_allocplain(duk_hthread *thr) {
	duk__hbufobj_fixed_from_argvalue(thr);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Uint8Array.plainOf()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_uint8array_plainof(duk_hthread *thr) {
	duk_hbufobj *h_bufobj;

#if !defined(DUK_USE_PREFER_SIZE)
	/* Avoid churn if argument is already a plain buffer. */
	if (duk_is_buffer(thr, 0)) {
		return 1;
	}
#endif

	/* Promotes plain buffers to ArrayBuffers, so for a plain buffer
	 * argument we'll create a pointless temporary (but still work
	 * correctly).
	 */
	h_bufobj = duk__require_bufobj_value(thr, 0);
	if (h_bufobj->buf == NULL) {
		duk_push_undefined(thr);
	} else {
		duk_push_hbuffer(thr, h_bufobj->buf);
	}
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer: toString([encoding], [start], [end])
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_tostring(duk_hthread *thr) {
	duk_hbufobj *h_this;
	duk_int_t start_offset, end_offset;
	duk_uint8_t *buf_slice;
	duk_size_t slice_length;

	h_this = duk__get_bufobj_this(thr);
	if (h_this == NULL) {
		/* XXX: happens e.g. when evaluating: String(Buffer.prototype). */
		duk_push_literal(thr, "[object Object]");
		return 1;
	}
	DUK_HBUFOBJ_ASSERT_VALID(h_this);

	/* Ignore encoding for now. */

	duk__clamp_startend_nonegidx_noshift(thr,
	                                     (duk_int_t) h_this->length,
	                                     1 /*idx_start*/,
	                                     2 /*idx_end*/,
	                                     &start_offset,
	                                     &end_offset);

	slice_length = (duk_size_t) (end_offset - start_offset);
	buf_slice = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, slice_length);  /* all bytes initialized below */
	DUK_ASSERT(buf_slice != NULL);

	/* Neutered or uncovered, TypeError. */
	if (h_this->buf == NULL ||
	    !DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_this, (duk_size_t) start_offset + slice_length)) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	/* XXX: ideally we wouldn't make a copy but a view into the buffer for the
	 * decoding process.  Or the decoding helper could be changed to accept
	 * the slice info (a buffer pointer is NOT a good approach because guaranteeing
	 * its stability is difficult).
	 */

	DUK_ASSERT(DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_this, (duk_size_t) start_offset + slice_length));
	duk_memcpy_unsafe((void *) buf_slice,
	                  (const void *) (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + start_offset),
	                  (size_t) slice_length);

	/* Use the equivalent of: new TextEncoder().encode(this) to convert the
	 * string.  Result will be valid UTF-8; non-CESU-8 inputs are currently
	 * interpreted loosely.  Value stack convention is a bit odd for now.
	 */
	duk_replace(thr, 0);
	duk_set_top(thr, 1);
	return duk_textdecoder_decode_utf8_nodejs(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype: toJSON()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_tojson(duk_hthread *thr) {
	duk_hbufobj *h_this;
	duk_uint8_t *buf;
	duk_uint_t i, n;
	duk_tval *tv;

	h_this = duk__require_bufobj_this(thr);
	DUK_ASSERT(h_this != NULL);

	if (h_this->buf == NULL || !DUK_HBUFOBJ_VALID_SLICE(h_this)) {
		/* Serialize uncovered backing buffer as a null; doesn't
		 * really matter as long we're memory safe.
		 */
		duk_push_null(thr);
		return 1;
	}

	duk_push_object(thr);
	duk_push_hstring_stridx(thr, DUK_STRIDX_UC_BUFFER);
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_TYPE);

	/* XXX: uninitialized would be OK */
	DUK_ASSERT_DISABLE((duk_size_t) h_this->length <= (duk_size_t) DUK_UINT32_MAX);
	tv = duk_push_harray_with_size_outptr(thr, (duk_uint32_t) h_this->length);  /* XXX: needs revision with >4G buffers */
	DUK_ASSERT(!duk_is_bare_object(thr, -1));

	DUK_ASSERT(h_this->buf != NULL);
	buf = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this);
	for (i = 0, n = h_this->length; i < n; i++) {
		DUK_TVAL_SET_U32(tv + i, (duk_uint32_t) buf[i]);  /* no need for decref or incref */
	}
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_DATA);

	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype.equals()
 *  Node.js Buffer.prototype.compare()
 *  Node.js Buffer.compare()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_buffer_compare_shared(duk_hthread *thr) {
	duk_small_uint_t magic;
	duk_hbufobj *h_bufarg1;
	duk_hbufobj *h_bufarg2;
	duk_small_int_t comp_res;

	/* XXX: keep support for plain buffers and non-Node.js buffers? */

	magic = (duk_small_uint_t) duk_get_current_magic(thr);
	if (magic & 0x02U) {
		/* Static call style. */
		h_bufarg1 = duk__require_bufobj_value(thr, 0);
		h_bufarg2 = duk__require_bufobj_value(thr, 1);
	} else {
		h_bufarg1 = duk__require_bufobj_this(thr);
		h_bufarg2 = duk__require_bufobj_value(thr, 0);
	}
	DUK_ASSERT(h_bufarg1 != NULL);
	DUK_ASSERT(h_bufarg2 != NULL);

	/* We want to compare the slice/view areas of the arguments.
	 * If either slice/view is invalid (underlying buffer is shorter)
	 * ensure equals() is false, but otherwise the only thing that
	 * matters is to be memory safe.
	 */

	if (DUK_HBUFOBJ_VALID_SLICE(h_bufarg1) &&
	    DUK_HBUFOBJ_VALID_SLICE(h_bufarg2)) {
		comp_res = duk_js_data_compare((const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufarg1->buf) + h_bufarg1->offset,
		                               (const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufarg2->buf) + h_bufarg2->offset,
		                               (duk_size_t) h_bufarg1->length,
		                               (duk_size_t) h_bufarg2->length);
	} else {
		comp_res = -1;  /* either nonzero value is ok */
	}

	if (magic & 0x01U) {
		/* compare: similar to string comparison but for buffer data. */
		duk_push_int(thr, comp_res);
	} else {
		/* equals */
		duk_push_boolean(thr, (comp_res == 0));
	}

	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype.fill()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_fill(duk_hthread *thr) {
	duk_hbufobj *h_this;
	const duk_uint8_t *fill_str_ptr;
	duk_size_t fill_str_len;
	duk_uint8_t fill_value;
	duk_int_t fill_offset;
	duk_int_t fill_end;
	duk_size_t fill_length;
	duk_uint8_t *p;

	h_this = duk__require_bufobj_this(thr);
	DUK_ASSERT(h_this != NULL);
	if (h_this->buf == NULL) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	/* [ value offset end ] */

	if (duk_is_string_notsymbol(thr, 0)) {
		fill_str_ptr = (const duk_uint8_t *) duk_get_lstring(thr, 0, &fill_str_len);
		DUK_ASSERT(fill_str_ptr != NULL);
	} else {
		/* Symbols get ToNumber() coerced and cause TypeError. */
		fill_value = (duk_uint8_t) duk_to_uint32(thr, 0);
		fill_str_ptr = (const duk_uint8_t *) &fill_value;
		fill_str_len = 1;
	}

	/* Fill offset handling is more lenient than in Node.js. */

	duk__clamp_startend_nonegidx_noshift(thr,
	                                     (duk_int_t) h_this->length,
	                                     1 /*idx_start*/,
	                                     2 /*idx_end*/,
	                                     &fill_offset,
	                                     &fill_end);

	DUK_DDD(DUK_DDDPRINT("fill: fill_value=%02x, fill_offset=%ld, fill_end=%ld, view length=%ld",
	                     (unsigned int) fill_value, (long) fill_offset, (long) fill_end, (long) h_this->length));

	DUK_ASSERT(fill_end - fill_offset >= 0);
	DUK_ASSERT(h_this->buf != NULL);

	p = (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + fill_offset);
	fill_length = (duk_size_t) (fill_end - fill_offset);
	if (fill_str_len == 1) {
		/* Handle single character fills as memset() even when
		 * the fill data comes from a one-char argument.
		 */
		duk_memset_unsafe((void *) p, (int) fill_str_ptr[0], (size_t) fill_length);
	} else if (fill_str_len > 1) {
		duk_size_t i, n, t;

		for (i = 0, n = (duk_size_t) (fill_end - fill_offset), t = 0; i < n; i++) {
			p[i] = fill_str_ptr[t++];
			if (t >= fill_str_len) {
				t = 0;
			}
		}
	} else {
		DUK_DDD(DUK_DDDPRINT("zero size fill pattern, ignore silently"));
	}

	/* Return the Buffer to allow chaining: b.fill(0x11).fill(0x22, 3, 5).toString() */
	duk_push_this(thr);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype.write(string, [offset], [length], [encoding])
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_write(duk_hthread *thr) {
	duk_hbufobj *h_this;
	duk_uint_t offset;
	duk_uint_t length;
	const duk_uint8_t *str_data;
	duk_size_t str_len;

	/* XXX: very inefficient support for plain buffers */
	h_this = duk__require_bufobj_this(thr);
	DUK_ASSERT(h_this != NULL);

	/* Argument must be a string, e.g. a buffer is not allowed. */
	str_data = (const duk_uint8_t *) duk_require_lstring_notsymbol(thr, 0, &str_len);

	duk__resolve_offset_opt_length(thr, h_this, 1, 2, &offset, &length, 0 /*throw_flag*/);
	DUK_ASSERT(offset <= h_this->length);
	DUK_ASSERT(offset + length <= h_this->length);

	/* XXX: encoding is ignored now. */

	if (length > str_len) {
		length = (duk_uint_t) str_len;
	}

	if (DUK_HBUFOBJ_VALID_SLICE(h_this)) {
		/* Cannot overlap. */
		duk_memcpy_unsafe((void *) (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + offset),
		                  (const void *) str_data,
		                  (size_t) length);
	} else {
		DUK_DDD(DUK_DDDPRINT("write() target buffer is not covered, silent ignore"));
	}

	duk_push_uint(thr, length);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype.copy()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_copy(duk_hthread *thr) {
	duk_hbufobj *h_this;
	duk_hbufobj *h_bufarg;
	duk_int_t source_length;
	duk_int_t target_length;
	duk_int_t target_start, source_start, source_end;
	duk_uint_t target_ustart, source_ustart, source_uend;
	duk_uint_t copy_size = 0;

	/* [ targetBuffer targetStart sourceStart sourceEnd ] */

	h_this = duk__require_bufobj_this(thr);
	h_bufarg = duk__require_bufobj_value(thr, 0);
	DUK_ASSERT(h_this != NULL);
	DUK_ASSERT(h_bufarg != NULL);
	source_length = (duk_int_t) h_this->length;
	target_length = (duk_int_t) h_bufarg->length;

	target_start = duk_to_int(thr, 1);
	source_start = duk_to_int(thr, 2);
	if (duk_is_undefined(thr, 3)) {
		source_end = source_length;
	} else {
		source_end = duk_to_int(thr, 3);
	}

	DUK_DDD(DUK_DDDPRINT("checking copy args: target_start=%ld, target_length=%ld, "
	                     "source_start=%ld, source_end=%ld, source_length=%ld",
	                     (long) target_start, (long) h_bufarg->length,
	                     (long) source_start, (long) source_end, (long) source_length));

	/* This behavior mostly mimics Node.js now. */

	if (source_start < 0 || source_end < 0 || target_start < 0) {
		/* Negative offsets cause a RangeError. */
		goto fail_bounds;
	}
	source_ustart = (duk_uint_t) source_start;
	source_uend = (duk_uint_t) source_end;
	target_ustart = (duk_uint_t) target_start;
	if (source_ustart >= source_uend ||  /* crossed offsets or zero size */
	    source_ustart >= (duk_uint_t) source_length ||  /* source out-of-bounds (but positive) */
	    target_ustart >= (duk_uint_t) target_length) {  /* target out-of-bounds (but positive) */
		goto silent_ignore;
	}
	if (source_uend >= (duk_uint_t) source_length) {
		/* Source end clamped silently to available length. */
		source_uend = (duk_uint_t) source_length;
	}
	copy_size = source_uend - source_ustart;
	if (target_ustart + copy_size > (duk_uint_t) target_length) {
		/* Clamp to target's end if too long.
		 *
		 * NOTE: there's no overflow possibility in the comparison;
		 * both target_ustart and copy_size are >= 0 and based on
		 * values in duk_int_t range.  Adding them as duk_uint_t
		 * values is then guaranteed not to overflow.
		 */
		DUK_ASSERT(target_ustart + copy_size >= target_ustart);  /* no overflow */
		DUK_ASSERT(target_ustart + copy_size >= copy_size);  /* no overflow */
		copy_size = (duk_uint_t) target_length - target_ustart;
	}

	DUK_DDD(DUK_DDDPRINT("making copy: target_ustart=%lu source_ustart=%lu copy_size=%lu",
	                     (unsigned long) target_ustart, (unsigned long) source_ustart,
	                     (unsigned long) copy_size));

	DUK_ASSERT(copy_size >= 1);
	DUK_ASSERT(source_ustart <= (duk_uint_t) source_length);
	DUK_ASSERT(source_ustart + copy_size <= (duk_uint_t) source_length);
	DUK_ASSERT(target_ustart <= (duk_uint_t) target_length);
	DUK_ASSERT(target_ustart + copy_size <= (duk_uint_t) target_length);

	/* Ensure copy is covered by underlying buffers. */
	DUK_ASSERT(h_bufarg->buf != NULL);  /* length check */
	DUK_ASSERT(h_this->buf != NULL);    /* length check */
	if (DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_bufarg, target_ustart + copy_size) &&
	    DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_this, source_ustart + copy_size)) {
		/* Must use memmove() because copy area may overlap (source and target
		 * buffer may be the same, or from different slices.
		 */
		duk_memmove_unsafe((void *) (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufarg) + target_ustart),
		                   (const void *) (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + source_ustart),
		                   (size_t) copy_size);
	} else {
		DUK_DDD(DUK_DDDPRINT("buffer copy not covered by underlying buffer(s), ignoring"));
	}

 silent_ignore:
	/* Return value is like write(), number of bytes written.
	 * The return value matters because of code like:
	 * "off += buf.copy(...)".
         */
	duk_push_uint(thr, copy_size);
	return 1;

 fail_bounds:
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  TypedArray.prototype.set()
 *
 *  TypedArray set() is pretty interesting to implement because:
 *
 *    - The source argument may be a plain array or a typedarray.  If the
 *      source is a TypedArray, values are decoded and re-encoded into the
 *      target (not as a plain byte copy).  This may happen even when the
 *      element byte size is the same, e.g. integer values may be re-encoded
 *      into floats.
 *
 *    - Source and target may refer to the same underlying buffer, so that
 *      the set() operation may overlap.  The specification requires that this
 *      must work as if a copy was made before the operation.  Note that this
 *      is NOT a simple memmove() situation because the source and target
 *      byte sizes may be different -- e.g. a 4-byte source (Int8Array) may
 *      expand to a 16-byte target (Uint32Array) so that the target overlaps
 *      the source both from beginning and the end (unlike in typical memmove).
 *
 *    - Even if 'buf' pointers of the source and target differ, there's no
 *      guarantee that their memory areas don't overlap.  This may be the
 *      case with external buffers.
 *
 *  Even so, it is nice to optimize for the common case:
 *
 *    - Source and target separate buffers or non-overlapping.
 *
 *    - Source and target have a compatible type so that a plain byte copy
 *      is possible.  Note that while e.g. uint8 and int8 are compatible
 *      (coercion one way or another doesn't change the byte representation),
 *      e.g. int8 and uint8clamped are NOT compatible when writing int8
 *      values into uint8clamped typedarray (-1 would clamp to 0 for instance).
 *
 *  See test-bi-typedarray-proto-set.js.
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_typedarray_set(duk_hthread *thr) {
	duk_hbufobj *h_this;
	duk_hobject *h_obj;
	duk_uarridx_t i, n;
	duk_int_t offset_signed;
	duk_uint_t offset_elems;
	duk_uint_t offset_bytes;

	h_this = duk__require_bufobj_this(thr);
	DUK_ASSERT(h_this != NULL);
	DUK_HBUFOBJ_ASSERT_VALID(h_this);

	if (h_this->buf == NULL) {
		DUK_DDD(DUK_DDDPRINT("source neutered, skip copy"));
		return 0;
	}

	duk_hbufobj_promote_plain(thr, 0);
	h_obj = duk_require_hobject(thr, 0);

	/* XXX: V8 throws a TypeError for negative values.  Would it
	 * be more useful to interpret negative offsets here from the
	 * end of the buffer too?
	 */
	offset_signed = duk_to_int(thr, 1);
	if (offset_signed < 0) {
		/* For some reason this is a TypeError (at least in V8). */
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}
	offset_elems = (duk_uint_t) offset_signed;
	offset_bytes = offset_elems << h_this->shift;
	if ((offset_bytes >> h_this->shift) != offset_elems) {
		/* Byte length would overflow. */
		/* XXX: easier check with less code? */
		goto fail_args;
	}
	if (offset_bytes > h_this->length) {
		/* Equality may be OK but >length not.  Checking
		 * this explicitly avoids some overflow cases
		 * below.
		 */
		goto fail_args;
	}
	DUK_ASSERT(offset_bytes <= h_this->length);

	/* Fast path: source is a TypedArray (or any bufobj). */

	if (DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
		duk_hbufobj *h_bufarg;
#if !defined(DUK_USE_PREFER_SIZE)
		duk_uint16_t comp_mask;
#endif
		duk_small_int_t no_overlap = 0;
		duk_uint_t src_length;
		duk_uint_t dst_length;
		duk_uint_t dst_length_elems;
		duk_uint8_t *p_src_base;
		duk_uint8_t *p_src_end;
		duk_uint8_t *p_src;
		duk_uint8_t *p_dst_base;
		duk_uint8_t *p_dst;
		duk_small_uint_t src_elem_size;
		duk_small_uint_t dst_elem_size;

		h_bufarg = (duk_hbufobj *) h_obj;
		DUK_HBUFOBJ_ASSERT_VALID(h_bufarg);

		if (h_bufarg->buf == NULL) {
			DUK_DDD(DUK_DDDPRINT("target neutered, skip copy"));
			return 0;
		}

		/* Nominal size check. */
		src_length = h_bufarg->length;  /* bytes in source */
		dst_length_elems = (src_length >> h_bufarg->shift);  /* elems in source and dest */
		dst_length = dst_length_elems << h_this->shift;  /* bytes in dest */
		if ((dst_length >> h_this->shift) != dst_length_elems) {
			/* Byte length would overflow. */
			/* XXX: easier check with less code? */
			goto fail_args;
		}
		DUK_DDD(DUK_DDDPRINT("nominal size check: src_length=%ld, dst_length=%ld",
		                     (long) src_length, (long) dst_length));
		DUK_ASSERT(offset_bytes <= h_this->length);
		if (dst_length > h_this->length - offset_bytes) {
			/* Overflow not an issue because subtraction is used on the right
			 * side and guaranteed to be >= 0.
			 */
			DUK_DDD(DUK_DDDPRINT("copy exceeds target buffer nominal length"));
			goto fail_args;
		}
		if (!DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_this, offset_bytes + dst_length)) {
			DUK_DDD(DUK_DDDPRINT("copy not covered by underlying target buffer, ignore"));
			return 0;
		}

		p_src_base = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufarg);
		p_dst_base = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + offset_bytes;

		/* Check actual underlying buffers for validity and that they
		 * cover the copy.  No side effects are allowed after the check
		 * so that the validity status doesn't change.
		 */
		if (!DUK_HBUFOBJ_VALID_SLICE(h_this) ||
		    !DUK_HBUFOBJ_VALID_SLICE(h_bufarg)) {
			/* The condition could be more narrow and check for the
			 * copy area only, but there's no need for fine grained
			 * behavior when the underlying buffer is misconfigured.
			 */
			DUK_DDD(DUK_DDDPRINT("source and/or target not covered by underlying buffer, skip copy"));
			return 0;
		}

		/* We want to do a straight memory copy if possible: this is
		 * an important operation because .set() is the TypedArray
		 * way to copy chunks of memory.  However, because set()
		 * conceptually works in terms of elements, not all views are
		 * compatible with direct byte copying.
		 *
		 * If we do manage a direct copy, the "overlap issue" handled
		 * below can just be solved using memmove() because the source
		 * and destination element sizes are necessarily equal.
		 */

#if !defined(DUK_USE_PREFER_SIZE)
		DUK_ASSERT(h_this->elem_type < sizeof(duk__buffer_elemtype_copy_compatible) / sizeof(duk_uint16_t));
		comp_mask = duk__buffer_elemtype_copy_compatible[h_this->elem_type];
		if (comp_mask & (1 << h_bufarg->elem_type)) {
			DUK_ASSERT(src_length == dst_length);

			DUK_DDD(DUK_DDDPRINT("fast path: able to use memmove() because views are compatible"));
			duk_memmove_unsafe((void *) p_dst_base, (const void *) p_src_base, (size_t) dst_length);
			return 0;
		}
		DUK_DDD(DUK_DDDPRINT("fast path: views are not compatible with a byte copy, copy by item"));
#endif  /* !DUK_USE_PREFER_SIZE */

		/* We want to avoid making a copy to process set() but that's
		 * not always possible: the source and the target may overlap
		 * and because element sizes are different, the overlap cannot
		 * always be handled with a memmove() or choosing the copy
		 * direction in a certain way.  For example, if source type is
		 * uint8 and target type is uint32, the target area may exceed
		 * the source area from both ends!
		 *
		 * Note that because external buffers may point to the same
		 * memory areas, we must ultimately make this check using
		 * pointers.
		 *
		 * NOTE: careful with side effects: any side effect may cause
		 * a buffer resize (or external buffer pointer/length update)!
		 */

		DUK_DDD(DUK_DDDPRINT("overlap check: p_src_base=%p, src_length=%ld, "
		                     "p_dst_base=%p, dst_length=%ld",
		                     (void *) p_src_base, (long) src_length,
		                     (void *) p_dst_base, (long) dst_length));

		if (p_src_base >= p_dst_base + dst_length ||  /* source starts after dest ends */
		    p_src_base + src_length <= p_dst_base) {   /* source ends before dest starts */
			no_overlap = 1;
		}

		if (!no_overlap) {
			/* There's overlap: the desired end result is that
			 * conceptually a copy is made to avoid "trampling"
			 * of source data by destination writes.  We make
			 * an actual temporary copy to handle this case.
			 */
			duk_uint8_t *p_src_copy;

			DUK_DDD(DUK_DDDPRINT("there is overlap, make a copy of the source"));
			p_src_copy = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, src_length);
			DUK_ASSERT(p_src_copy != NULL);
			duk_memcpy_unsafe((void *) p_src_copy, (const void *) p_src_base, (size_t) src_length);

			p_src_base = p_src_copy;  /* use p_src_base from now on */
		}
		/* Value stack intentionally mixed size here. */

		DUK_DDD(DUK_DDDPRINT("after overlap check: p_src_base=%p, src_length=%ld, "
		                     "p_dst_base=%p, dst_length=%ld, valstack top=%ld",
		                     (void *) p_src_base, (long) src_length,
		                     (void *) p_dst_base, (long) dst_length,
		                     (long) duk_get_top(thr)));

		/* Ready to make the copy.  We must proceed element by element
		 * and must avoid any side effects that might cause the buffer
		 * validity check above to become invalid.
		 *
		 * Although we work through the value stack here, only plain
		 * numbers are handled which should be side effect safe.
		 */

		src_elem_size = (duk_small_uint_t) (1U << h_bufarg->shift);
		dst_elem_size = (duk_small_uint_t) (1U << h_this->shift);
		p_src = p_src_base;
		p_dst = p_dst_base;
		p_src_end = p_src_base + src_length;

		while (p_src != p_src_end) {
			DUK_DDD(DUK_DDDPRINT("fast path per element copy loop: "
			                     "p_src=%p, p_src_end=%p, p_dst=%p",
			                     (void *) p_src, (void *) p_src_end, (void *) p_dst));
			/* A validated read() is always a number, so it's write coercion
			 * is always side effect free an won't invalidate pointers etc.
			 */
			duk_hbufobj_push_validated_read(thr, h_bufarg, p_src, src_elem_size);
			duk_hbufobj_validated_write(thr, h_this, p_dst, dst_elem_size);
			duk_pop(thr);
			p_src += src_elem_size;
			p_dst += dst_elem_size;
		}

		return 0;
	} else {
		/* Slow path: quite slow, but we save space by using the property code
		 * to write coerce target values.  We don't need to worry about overlap
		 * here because the source is not a TypedArray.
		 *
		 * We could use the bufobj write coercion helper but since the
		 * property read may have arbitrary side effects, full validity checks
		 * would be needed for every element anyway.
		 */

		n = (duk_uarridx_t) duk_get_length(thr, 0);
		DUK_ASSERT(offset_bytes <= h_this->length);
		if ((n << h_this->shift) > h_this->length - offset_bytes) {
			/* Overflow not an issue because subtraction is used on the right
			 * side and guaranteed to be >= 0.
			 */
			DUK_DDD(DUK_DDDPRINT("copy exceeds target buffer nominal length"));
			goto fail_args;
		}

		/* There's no need to check for buffer validity status for the
		 * target here: the property access code will do that for each
		 * element.  Moreover, if we did check the validity here, side
		 * effects from reading the source argument might invalidate
		 * the results anyway.
		 */

		DUK_ASSERT_TOP(thr, 2);
		duk_push_this(thr);

		for (i = 0; i < n; i++) {
			duk_get_prop_index(thr, 0, i);
			duk_put_prop_index(thr, 2, offset_elems + i);
		}
	}

	return 0;

 fail_args:
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.prototype.slice([start], [end])
 *  ArrayBuffer.prototype.slice(begin, [end])
 *  TypedArray.prototype.subarray(begin, [end])
 *
 *  The API calls are almost identical; negative indices are counted from end
 *  of buffer, and final indices are clamped (allowing crossed indices).  Main
 *  differences:
 *
 *    - Copy/view behavior; Node.js .slice() and TypedArray .subarray() create
 *      views, ArrayBuffer .slice() creates a copy
 *
 *    - Resulting object has a different class and prototype depending on the
 *      call (or 'this' argument)
 *
 *    - TypedArray .subarray() arguments are element indices, not byte offsets
 *
 *    - Plain buffer argument creates a plain buffer slice
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_LOCAL void duk__arraybuffer_plain_slice(duk_hthread *thr, duk_hbuffer *h_val) {
	duk_int_t start_offset, end_offset;
	duk_uint_t slice_length;
	duk_uint8_t *p_copy;
	duk_size_t copy_length;

	duk__clamp_startend_negidx_shifted(thr,
	                                   (duk_int_t) DUK_HBUFFER_GET_SIZE(h_val),
	                                   0 /*buffer_shift*/,
	                                   0 /*idx_start*/,
	                                   1 /*idx_end*/,
	                                   &start_offset,
	                                   &end_offset);
	DUK_ASSERT(end_offset <= (duk_int_t) DUK_HBUFFER_GET_SIZE(h_val));
	DUK_ASSERT(start_offset >= 0);
	DUK_ASSERT(end_offset >= start_offset);
	slice_length = (duk_uint_t) (end_offset - start_offset);

	p_copy = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, (duk_size_t) slice_length);
	DUK_ASSERT(p_copy != NULL);
	copy_length = slice_length;

	duk_memcpy_unsafe((void *) p_copy,
	                  (const void *) ((duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_val) + start_offset),
	                  copy_length);
}
#endif /* DUK_USE_BUFFEROBJECT_SUPPORT */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
/* Shared helper for slice/subarray operation.
 * Magic: 0x01=isView, 0x02=copy, 0x04=Node.js Buffer special handling.
 */
DUK_INTERNAL duk_ret_t duk_bi_buffer_slice_shared(duk_hthread *thr) {
	duk_small_int_t magic;
	duk_small_uint_t res_class_num;
	duk_small_int_t res_proto_bidx;
	duk_hbufobj *h_this;
	duk_hbufobj *h_bufobj;
	duk_hbuffer *h_val;
	duk_int_t start_offset, end_offset;
	duk_uint_t slice_length;
	duk_tval *tv;

	/* [ start end ] */

	magic = duk_get_current_magic(thr);

	tv = duk_get_borrowed_this_tval(thr);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_BUFFER(tv)) {
		/* For plain buffers return a plain buffer slice. */
		h_val = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h_val != NULL);

		if (magic & 0x02) {
			/* Make copy: ArrayBuffer.prototype.slice() uses this. */
			duk__arraybuffer_plain_slice(thr, h_val);
			return 1;
		} else {
			/* View into existing buffer: cannot be done if the
			 * result is a plain buffer because there's no slice
			 * info.  So return an ArrayBuffer instance; coerce
			 * the 'this' binding into an object and behave as if
			 * the original call was for an Object-coerced plain
			 * buffer (handled automatically by duk__require_bufobj_this()).
			 */

			DUK_DDD(DUK_DDDPRINT("slice() doesn't handle view into plain buffer, coerce 'this' to ArrayBuffer object"));
			/* fall through */
		}
	}
	tv = NULL;  /* No longer valid nor needed. */

	h_this = duk__require_bufobj_this(thr);

	/* Slice offsets are element (not byte) offsets, which only matters
	 * for TypedArray views, Node.js Buffer and ArrayBuffer have shift
	 * zero so byte and element offsets are the same.  Negative indices
	 * are counted from end of slice, crossed indices are allowed (and
	 * result in zero length result), and final values are clamped
	 * against the current slice.  There's intentionally no check
	 * against the underlying buffer here.
	 */

	duk__clamp_startend_negidx_shifted(thr,
	                                   (duk_int_t) h_this->length,
	                                   (duk_uint8_t) h_this->shift,
	                                   0 /*idx_start*/,
	                                   1 /*idx_end*/,
	                                   &start_offset,
	                                   &end_offset);
	DUK_ASSERT(end_offset >= start_offset);
	DUK_ASSERT(start_offset >= 0);
	DUK_ASSERT(end_offset >= 0);
	slice_length = (duk_uint_t) (end_offset - start_offset);

	/* The resulting buffer object gets the same class and prototype as
	 * the buffer in 'this', e.g. if the input is a Uint8Array the
	 * result is a Uint8Array; if the input is a Float32Array, the
	 * result is a Float32Array.  The result internal prototype should
	 * be the default prototype for the class (e.g. initial value of
	 * Uint8Array.prototype), not copied from the argument (Duktape 1.x
	 * did that).
	 *
	 * Node.js Buffers have special handling: they're Uint8Arrays as far
	 * as the internal class is concerned, so the new Buffer should also
	 * be an Uint8Array but inherit from Buffer.prototype.
	 */
	res_class_num = DUK_HOBJECT_GET_CLASS_NUMBER((duk_hobject *) h_this);
	DUK_ASSERT(res_class_num >= DUK_HOBJECT_CLASS_BUFOBJ_MIN);  /* type check guarantees */
	DUK_ASSERT(res_class_num <= DUK_HOBJECT_CLASS_BUFOBJ_MAX);
	res_proto_bidx = duk__buffer_proto_from_classnum[res_class_num - DUK_HOBJECT_CLASS_BUFOBJ_MIN];
	if (magic & 0x04) {
		res_proto_bidx = DUK_BIDX_NODEJS_BUFFER_PROTOTYPE;
	}
	h_bufobj = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(res_class_num),
	                               res_proto_bidx);
	DUK_ASSERT(h_bufobj != NULL);

	DUK_ASSERT(h_bufobj->length == 0);
	h_bufobj->shift = h_this->shift;  /* inherit */
	h_bufobj->elem_type = h_this->elem_type;  /* inherit */
	h_bufobj->is_typedarray = magic & 0x01;
	DUK_ASSERT(h_bufobj->is_typedarray == 0 || h_bufobj->is_typedarray == 1);

	h_val = h_this->buf;
	if (h_val == NULL) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	if (magic & 0x02) {
		/* non-zero: make copy */
		duk_uint8_t *p_copy;
		duk_size_t copy_length;

		p_copy = (duk_uint8_t *) duk_push_fixed_buffer_zero(thr, (duk_size_t) slice_length);  /* must be zeroed, not all bytes always copied */
		DUK_ASSERT(p_copy != NULL);

		/* Copy slice, respecting underlying buffer limits; remainder
		 * is left as zero.
		 */
		copy_length = DUK_HBUFOBJ_CLAMP_BYTELENGTH(h_this, slice_length);
		duk_memcpy_unsafe((void *) p_copy,
		                  (const void *) (DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this) + start_offset),
		                  copy_length);

		h_val = duk_known_hbuffer(thr, -1);

		h_bufobj->buf = h_val;
		DUK_HBUFFER_INCREF(thr, h_val);
		h_bufobj->length = slice_length;
		DUK_ASSERT(h_bufobj->offset == 0);

		duk_pop(thr);  /* reachable so pop OK */
	} else {
		h_bufobj->buf = h_val;
		DUK_HBUFFER_INCREF(thr, h_val);
		h_bufobj->length = slice_length;
		h_bufobj->offset = h_this->offset + (duk_uint_t) start_offset;

		/* Copy the .buffer property, needed for TypedArray.prototype.subarray().
		 *
		 * XXX: limit copy only for TypedArray classes specifically?
		 */

		DUK_ASSERT(h_bufobj->buf_prop == NULL);
		h_bufobj->buf_prop = h_this->buf_prop;  /* may be NULL */
		DUK_HOBJECT_INCREF_ALLOWNULL(thr, (duk_hobject *) h_bufobj->buf_prop);
	}
	/* unbalanced stack on purpose */

	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.isEncoding()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_is_encoding(duk_hthread *thr) {
	const char *encoding;

	/* only accept lowercase 'utf8' now. */

	encoding = duk_to_string(thr, 0);
	DUK_ASSERT(duk_is_string(thr, 0));  /* guaranteed by duk_to_string() */
	duk_push_boolean(thr, DUK_STRCMP(encoding, "utf8") == 0);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.isBuffer()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_is_buffer(duk_hthread *thr) {
	duk_hobject *h;
	duk_hobject *h_proto;
	duk_bool_t ret = 0;

	DUK_ASSERT(duk_get_top(thr) >= 1);  /* nargs */
	h = duk_get_hobject(thr, 0);
	if (h != NULL) {
		h_proto = thr->builtins[DUK_BIDX_NODEJS_BUFFER_PROTOTYPE];
		DUK_ASSERT(h_proto != NULL);

		h = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h);
		if (h != NULL) {
			ret = duk_hobject_prototype_chain_contains(thr, h, h_proto, 0 /*ignore_loop*/);
		}
	}

	duk_push_boolean(thr, ret);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.byteLength()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_byte_length(duk_hthread *thr) {
	const char *str;
	duk_size_t len;

	/* At the moment Buffer(<str>) will just use the string bytes as
	 * is (ignoring encoding), so we return the string length here
	 * unconditionally.
	 */

	/* XXX: to be revised; Old Node.js behavior just coerces any buffer
	 * values to string:
	 * $ node
	 * > Buffer.byteLength(new Uint32Array(10))
	 * 20
	 * > Buffer.byteLength(new Uint32Array(100))
	 * 20
	 * (The 20 comes from '[object Uint32Array]'.length
	 */

	str = duk_to_lstring(thr, 0, &len);
	DUK_UNREF(str);
	duk_push_size_t(thr, len);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Node.js Buffer.concat()
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_nodejs_buffer_concat(duk_hthread *thr) {
	duk_hobject *h_arg;
	duk_uint_t total_length;
	duk_hbufobj *h_bufobj;
	duk_hbufobj *h_bufres;
	duk_hbuffer *h_val;
	duk_uint_t i, n;
	duk_uint8_t *p;
	duk_size_t space_left;
	duk_size_t copy_size;

	/* Node.js accepts only actual Arrays. */
	h_arg = duk_require_hobject(thr, 0);
	if (DUK_HOBJECT_GET_CLASS_NUMBER(h_arg) != DUK_HOBJECT_CLASS_ARRAY) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	/* Compute result length and validate argument buffers. */
	n = (duk_uint_t) duk_get_length(thr, 0);
	total_length = 0;
	for (i = 0; i < n; i++) {
		/* Neutered checks not necessary here: neutered buffers have
		 * zero 'length' so we'll effectively skip them.
		 */
		DUK_ASSERT_TOP(thr, 2);  /* [ array totalLength ] */
		duk_get_prop_index(thr, 0, (duk_uarridx_t) i);  /* -> [ array totalLength buf ] */
		h_bufobj = duk__require_bufobj_value(thr, 2);
		DUK_ASSERT(h_bufobj != NULL);
		total_length += h_bufobj->length;
		if (DUK_UNLIKELY(total_length < h_bufobj->length)) {
			DUK_DCERROR_RANGE_INVALID_ARGS(thr);  /* Wrapped. */
		}
		duk_pop(thr);
	}
	/* In Node.js v0.12.1 a 1-element array is special and won't create a
	 * copy, this was fixed later so an explicit check no longer needed.
	 */

	/* User totalLength overrides a computed length, but we'll check
	 * every copy in the copy loop.  Note that duk_to_int() can
	 * technically have arbitrary side effects so we need to recheck
	 * the buffers in the copy loop.
	 */
	if (!duk_is_undefined(thr, 1) && n > 0) {
		/* For n == 0, Node.js ignores totalLength argument and
		 * returns a zero length buffer.
		 */
		duk_int_t total_length_signed;
		total_length_signed = duk_to_int(thr, 1);
		if (total_length_signed < 0) {
			DUK_DCERROR_RANGE_INVALID_ARGS(thr);
		}
		total_length = (duk_uint_t) total_length_signed;
	}

	h_bufres = duk_push_bufobj_raw(thr,
	                               DUK_HOBJECT_FLAG_EXTENSIBLE |
	                               DUK_HOBJECT_FLAG_BUFOBJ |
	                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_UINT8ARRAY),
	                               DUK_BIDX_NODEJS_BUFFER_PROTOTYPE);
	DUK_ASSERT(h_bufres != NULL);

	p = (duk_uint8_t *) duk_push_fixed_buffer_zero(thr, total_length);  /* must be zeroed, all bytes not necessarily written over */
	DUK_ASSERT(p != NULL);
	space_left = (duk_size_t) total_length;

	for (i = 0; i < n; i++) {
		DUK_ASSERT_TOP(thr, 4);  /* [ array totalLength bufres buf ] */

		duk_get_prop_index(thr, 0, (duk_uarridx_t) i);
		h_bufobj = duk__require_bufobj_value(thr, 4);
		DUK_ASSERT(h_bufobj != NULL);

		copy_size = h_bufobj->length;
		if (copy_size > space_left) {
			copy_size = space_left;
		}

		if (h_bufobj->buf != NULL &&
		    DUK_HBUFOBJ_VALID_SLICE(h_bufobj)) {
			duk_memcpy_unsafe((void *) p,
			                  (const void *) DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_bufobj),
			                  copy_size);
		} else {
			/* Just skip, leaving zeroes in the result. */
			;
		}
		p += copy_size;
		space_left -= copy_size;

		duk_pop(thr);
	}

	h_val = duk_known_hbuffer(thr, -1);

	duk__set_bufobj_buffer(thr, h_bufres, h_val);
	h_bufres->is_typedarray = 1;
	DUK_HBUFOBJ_ASSERT_VALID(h_bufres);

	duk_pop(thr);  /* pop plain buffer, now reachable through h_bufres */

	return 1;  /* return h_bufres */
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Shared readfield and writefield methods
 *
 *  The readfield/writefield methods need support for endianness and field
 *  types.  All offsets are byte based so no offset shifting is needed.
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
/* Format of magic, bits:
 *   0...1: field type; 0=uint8, 1=uint16, 2=uint32, 3=float, 4=double, 5=unused, 6=unused, 7=unused
 *       3: endianness: 0=little, 1=big
 *       4: signed: 1=yes, 0=no
 *       5: typedarray: 1=yes, 0=no
 */
#define  DUK__FLD_8BIT         0
#define  DUK__FLD_16BIT        1
#define  DUK__FLD_32BIT        2
#define  DUK__FLD_FLOAT        3
#define  DUK__FLD_DOUBLE       4
#define  DUK__FLD_VARINT       5
#define  DUK__FLD_BIGENDIAN    (1 << 3)
#define  DUK__FLD_SIGNED       (1 << 4)
#define  DUK__FLD_TYPEDARRAY   (1 << 5)

/* XXX: split into separate functions for each field type? */
DUK_INTERNAL duk_ret_t duk_bi_buffer_readfield(duk_hthread *thr) {
	duk_small_uint_t magic = (duk_small_uint_t) duk_get_current_magic(thr);
	duk_small_uint_t magic_ftype;
	duk_small_uint_t magic_bigendian;
	duk_small_uint_t magic_signed;
	duk_small_uint_t magic_typedarray;
	duk_small_uint_t endswap;
	duk_hbufobj *h_this;
	duk_bool_t no_assert;
	duk_int_t offset_signed;
	duk_uint_t offset;
	duk_uint_t buffer_length;
	duk_uint_t check_length;
	duk_uint8_t *buf;
	duk_double_union du;

	magic_ftype = magic & 0x0007U;
	magic_bigendian = magic & 0x0008U;
	magic_signed = magic & 0x0010U;
	magic_typedarray = magic & 0x0020U;

	h_this = duk__require_bufobj_this(thr);  /* XXX: very inefficient for plain buffers */
	DUK_ASSERT(h_this != NULL);
	buffer_length = h_this->length;

	/* [ offset noAssert                 ], when ftype != DUK__FLD_VARINT */
	/* [ offset fieldByteLength noAssert ], when ftype == DUK__FLD_VARINT */
	/* [ offset littleEndian             ], when DUK__FLD_TYPEDARRAY (regardless of ftype) */

	/* Handle TypedArray vs. Node.js Buffer arg differences */
	if (magic_typedarray) {
		no_assert = 0;
#if defined(DUK_USE_INTEGER_LE)
		endswap = !duk_to_boolean(thr, 1);  /* 1=little endian */
#else
		endswap = duk_to_boolean(thr, 1);  /* 1=little endian */
#endif
	} else {
		no_assert = duk_to_boolean(thr, (magic_ftype == DUK__FLD_VARINT) ? 2 : 1);
#if defined(DUK_USE_INTEGER_LE)
		endswap = magic_bigendian;
#else
		endswap = !magic_bigendian;
#endif
	}

	/* Offset is coerced first to signed integer range and then to unsigned.
	 * This ensures we can add a small byte length (1-8) to the offset in
	 * bound checks and not wrap.
	 */
	offset_signed = duk_to_int(thr, 0);
	offset = (duk_uint_t) offset_signed;
	if (offset_signed < 0) {
		goto fail_bounds;
	}

	DUK_DDD(DUK_DDDPRINT("readfield, buffer_length=%ld, offset=%ld, no_assert=%d, "
	                     "magic=%04x, magic_fieldtype=%d, magic_bigendian=%d, magic_signed=%d, "
	                     "endswap=%u",
	                     (long) buffer_length, (long) offset, (int) no_assert,
	                     (unsigned int) magic, (int) magic_ftype, (int) (magic_bigendian >> 3),
	                     (int) (magic_signed >> 4), (int) endswap));

	/* Update 'buffer_length' to be the effective, safe limit which
	 * takes into account the underlying buffer.  This value will be
	 * potentially invalidated by any side effect.
	 */
	check_length = DUK_HBUFOBJ_CLAMP_BYTELENGTH(h_this, buffer_length);
	DUK_DDD(DUK_DDDPRINT("buffer_length=%ld, check_length=%ld",
	                     (long) buffer_length, (long) check_length));

	if (h_this->buf) {
		buf = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this);
	} else {
		/* Neutered.  We could go into the switch-case safely with
		 * buf == NULL because check_length == 0.  To avoid scanbuild
		 * warnings, fail directly instead.
		 */
		DUK_ASSERT(check_length == 0);
		goto fail_neutered;
	}
	DUK_ASSERT(buf != NULL);

	switch (magic_ftype) {
	case DUK__FLD_8BIT: {
		duk_uint8_t tmp;
		if (offset + 1U > check_length) {
			goto fail_bounds;
		}
		tmp = buf[offset];
		if (magic_signed) {
			duk_push_int(thr, (duk_int_t) ((duk_int8_t) tmp));
		} else {
			duk_push_uint(thr, (duk_uint_t) tmp);
		}
		break;
	}
	case DUK__FLD_16BIT: {
		duk_uint16_t tmp;
		if (offset + 2U > check_length) {
			goto fail_bounds;
		}
		duk_memcpy((void *) du.uc, (const void *) (buf + offset), 2);
		tmp = du.us[0];
		if (endswap) {
			tmp = DUK_BSWAP16(tmp);
		}
		if (magic_signed) {
			duk_push_int(thr, (duk_int_t) ((duk_int16_t) tmp));
		} else {
			duk_push_uint(thr, (duk_uint_t) tmp);
		}
		break;
	}
	case DUK__FLD_32BIT: {
		duk_uint32_t tmp;
		if (offset + 4U > check_length) {
			goto fail_bounds;
		}
		duk_memcpy((void *) du.uc, (const void *) (buf + offset), 4);
		tmp = du.ui[0];
		if (endswap) {
			tmp = DUK_BSWAP32(tmp);
		}
		if (magic_signed) {
			duk_push_int(thr, (duk_int_t) ((duk_int32_t) tmp));
		} else {
			duk_push_uint(thr, (duk_uint_t) tmp);
		}
		break;
	}
	case DUK__FLD_FLOAT: {
		duk_uint32_t tmp;
		if (offset + 4U > check_length) {
			goto fail_bounds;
		}
		duk_memcpy((void *) du.uc, (const void *) (buf + offset), 4);
		if (endswap) {
			tmp = du.ui[0];
			tmp = DUK_BSWAP32(tmp);
			du.ui[0] = tmp;
		}
		duk_push_number(thr, (duk_double_t) du.f[0]);
		break;
	}
	case DUK__FLD_DOUBLE: {
		if (offset + 8U > check_length) {
			goto fail_bounds;
		}
		duk_memcpy((void *) du.uc, (const void *) (buf + offset), 8);
		if (endswap) {
			DUK_DBLUNION_BSWAP64(&du);
		}
		duk_push_number(thr, (duk_double_t) du.d);
		break;
	}
	case DUK__FLD_VARINT: {
		/* Node.js Buffer variable width integer field.  We don't really
		 * care about speed here, so aim for shortest algorithm.
		 */
		duk_int_t field_bytelen;
		duk_int_t i, i_step, i_end;
#if defined(DUK_USE_64BIT_OPS)
		duk_int64_t tmp;
		duk_small_uint_t shift_tmp;
#else
		duk_double_t tmp;
		duk_small_int_t highbyte;
#endif
		const duk_uint8_t *p;

		field_bytelen = duk_get_int(thr, 1);  /* avoid side effects! */
		if (field_bytelen < 1 || field_bytelen > 6) {
			goto fail_field_length;
		}
		if (offset + (duk_uint_t) field_bytelen > check_length) {
			goto fail_bounds;
		}
		p = (const duk_uint8_t *) (buf + offset);

		/* Slow gathering of value using either 64-bit arithmetic
		 * or IEEE doubles if 64-bit types not available.  Handling
		 * of negative numbers is a bit non-obvious in both cases.
		 */

		if (magic_bigendian) {
			/* Gather in big endian */
			i = 0;
			i_step = 1;
			i_end = field_bytelen;  /* one i_step over */
		} else {
			/* Gather in little endian */
			i = field_bytelen - 1;
			i_step = -1;
			i_end = -1;  /* one i_step over */
		}

#if defined(DUK_USE_64BIT_OPS)
		tmp = 0;
		do {
			DUK_ASSERT(i >= 0 && i < field_bytelen);
			tmp = (tmp << 8) + (duk_int64_t) p[i];
			i += i_step;
		} while (i != i_end);

		if (magic_signed) {
			/* Shift to sign extend.  Left shift must be unsigned
			 * to avoid undefined behavior; right shift must be
			 * signed to sign extend properly.
			 */
			shift_tmp = (duk_small_uint_t) (64U - (duk_small_uint_t) field_bytelen * 8U);
			tmp = (duk_int64_t) ((duk_uint64_t) tmp << shift_tmp) >> shift_tmp;
		}

		duk_push_i64(thr, tmp);
#else
		highbyte = p[i];
		if (magic_signed && (highbyte & 0x80) != 0) {
			/* 0xff => 255 - 256 = -1; 0x80 => 128 - 256 = -128 */
			tmp = (duk_double_t) (highbyte - 256);
		} else {
			tmp = (duk_double_t) highbyte;
		}
		for (;;) {
			i += i_step;
			if (i == i_end) {
				break;
			}
			DUK_ASSERT(i >= 0 && i < field_bytelen);
			tmp = (tmp * 256.0) + (duk_double_t) p[i];
		}

		duk_push_number(thr, tmp);
#endif
		break;
	}
	default: {  /* should never happen but default here */
		goto fail_bounds;
	}
	}

	return 1;

 fail_neutered:
 fail_field_length:
 fail_bounds:
	if (no_assert) {
		/* Node.js return value for noAssert out-of-bounds reads is
		 * usually (but not always) NaN.  Return NaN consistently.
		 */
		duk_push_nan(thr);
		return 1;
	}
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
/* XXX: split into separate functions for each field type? */
DUK_INTERNAL duk_ret_t duk_bi_buffer_writefield(duk_hthread *thr) {
	duk_small_uint_t magic = (duk_small_uint_t) duk_get_current_magic(thr);
	duk_small_uint_t magic_ftype;
	duk_small_uint_t magic_bigendian;
	duk_small_uint_t magic_signed;
	duk_small_uint_t magic_typedarray;
	duk_small_uint_t endswap;
	duk_hbufobj *h_this;
	duk_bool_t no_assert;
	duk_int_t offset_signed;
	duk_uint_t offset;
	duk_uint_t buffer_length;
	duk_uint_t check_length;
	duk_uint8_t *buf;
	duk_double_union du;
	duk_int_t nbytes = 0;

	magic_ftype = magic & 0x0007U;
	magic_bigendian = magic & 0x0008U;
	magic_signed = magic & 0x0010U;
	magic_typedarray = magic & 0x0020U;
	DUK_UNREF(magic_signed);

	h_this = duk__require_bufobj_this(thr);  /* XXX: very inefficient for plain buffers */
	DUK_ASSERT(h_this != NULL);
	buffer_length = h_this->length;

	/* [ value  offset noAssert                 ], when ftype != DUK__FLD_VARINT */
	/* [ value  offset fieldByteLength noAssert ], when ftype == DUK__FLD_VARINT */
	/* [ offset value  littleEndian             ], when DUK__FLD_TYPEDARRAY (regardless of ftype) */

	/* Handle TypedArray vs. Node.js Buffer arg differences */
	if (magic_typedarray) {
		no_assert = 0;
#if defined(DUK_USE_INTEGER_LE)
		endswap = !duk_to_boolean(thr, 2);  /* 1=little endian */
#else
		endswap = duk_to_boolean(thr, 2);  /* 1=little endian */
#endif
		duk_swap(thr, 0, 1);  /* offset/value order different from Node.js */
	} else {
		no_assert = duk_to_boolean(thr, (magic_ftype == DUK__FLD_VARINT) ? 3 : 2);
#if defined(DUK_USE_INTEGER_LE)
		endswap = magic_bigendian;
#else
		endswap = !magic_bigendian;
#endif
	}

	/* Offset is coerced first to signed integer range and then to unsigned.
	 * This ensures we can add a small byte length (1-8) to the offset in
	 * bound checks and not wrap.
	 */
	offset_signed = duk_to_int(thr, 1);
	offset = (duk_uint_t) offset_signed;

	/* We need 'nbytes' even for a failed offset; return value must be
	 * (offset + nbytes) even when write fails due to invalid offset.
	 */
	if (magic_ftype != DUK__FLD_VARINT) {
		DUK_ASSERT(magic_ftype < (duk_small_uint_t) (sizeof(duk__buffer_nbytes_from_fldtype) / sizeof(duk_uint8_t)));
		nbytes = duk__buffer_nbytes_from_fldtype[magic_ftype];
	} else {
		nbytes = duk_get_int(thr, 2);
		if (nbytes < 1 || nbytes > 6) {
			goto fail_field_length;
		}
	}
	DUK_ASSERT(nbytes >= 1 && nbytes <= 8);

	/* Now we can check offset validity. */
	if (offset_signed < 0) {
		goto fail_bounds;
	}

	DUK_DDD(DUK_DDDPRINT("writefield, value=%!T, buffer_length=%ld, offset=%ld, no_assert=%d, "
	                     "magic=%04x, magic_fieldtype=%d, magic_bigendian=%d, magic_signed=%d, "
	                     "endswap=%u",
	                     duk_get_tval(thr, 0), (long) buffer_length, (long) offset, (int) no_assert,
	                     (unsigned int) magic, (int) magic_ftype, (int) (magic_bigendian >> 3),
	                     (int) (magic_signed >> 4), (int) endswap));

	/* Coerce value to a number before computing check_length, so that
	 * the field type specific coercion below can't have side effects
	 * that would invalidate check_length.
	 */
	duk_to_number(thr, 0);

	/* Update 'buffer_length' to be the effective, safe limit which
	 * takes into account the underlying buffer.  This value will be
	 * potentially invalidated by any side effect.
	 */
	check_length = DUK_HBUFOBJ_CLAMP_BYTELENGTH(h_this, buffer_length);
	DUK_DDD(DUK_DDDPRINT("buffer_length=%ld, check_length=%ld",
	                     (long) buffer_length, (long) check_length));

	if (h_this->buf) {
		buf = DUK_HBUFOBJ_GET_SLICE_BASE(thr->heap, h_this);
	} else {
		/* Neutered.  We could go into the switch-case safely with
		 * buf == NULL because check_length == 0.  To avoid scanbuild
		 * warnings, fail directly instead.
		 */
		DUK_ASSERT(check_length == 0);
		goto fail_neutered;
	}
	DUK_ASSERT(buf != NULL);

	switch (magic_ftype) {
	case DUK__FLD_8BIT: {
		if (offset + 1U > check_length) {
			goto fail_bounds;
		}
		/* sign doesn't matter when writing */
		buf[offset] = (duk_uint8_t) duk_to_uint32(thr, 0);
		break;
	}
	case DUK__FLD_16BIT: {
		duk_uint16_t tmp;
		if (offset + 2U > check_length) {
			goto fail_bounds;
		}
		tmp = (duk_uint16_t) duk_to_uint32(thr, 0);
		if (endswap) {
			tmp = DUK_BSWAP16(tmp);
		}
		du.us[0] = tmp;
		/* sign doesn't matter when writing */
		duk_memcpy((void *) (buf + offset), (const void *) du.uc, 2);
		break;
	}
	case DUK__FLD_32BIT: {
		duk_uint32_t tmp;
		if (offset + 4U > check_length) {
			goto fail_bounds;
		}
		tmp = (duk_uint32_t) duk_to_uint32(thr, 0);
		if (endswap) {
			tmp = DUK_BSWAP32(tmp);
		}
		du.ui[0] = tmp;
		/* sign doesn't matter when writing */
		duk_memcpy((void *) (buf + offset), (const void *) du.uc, 4);
		break;
	}
	case DUK__FLD_FLOAT: {
		duk_uint32_t tmp;
		if (offset + 4U > check_length) {
			goto fail_bounds;
		}
		du.f[0] = (duk_float_t) duk_to_number(thr, 0);
		if (endswap) {
			tmp = du.ui[0];
			tmp = DUK_BSWAP32(tmp);
			du.ui[0] = tmp;
		}
		/* sign doesn't matter when writing */
		duk_memcpy((void *) (buf + offset), (const void *) du.uc, 4);
		break;
	}
	case DUK__FLD_DOUBLE: {
		if (offset + 8U > check_length) {
			goto fail_bounds;
		}
		du.d = (duk_double_t) duk_to_number(thr, 0);
		if (endswap) {
			DUK_DBLUNION_BSWAP64(&du);
		}
		/* sign doesn't matter when writing */
		duk_memcpy((void *) (buf + offset), (const void *) du.uc, 8);
		break;
	}
	case DUK__FLD_VARINT: {
		/* Node.js Buffer variable width integer field.  We don't really
		 * care about speed here, so aim for shortest algorithm.
		 */
		duk_int_t field_bytelen;
		duk_int_t i, i_step, i_end;
#if defined(DUK_USE_64BIT_OPS)
		duk_int64_t tmp;
#else
		duk_double_t tmp;
#endif
		duk_uint8_t *p;

		field_bytelen = (duk_int_t) nbytes;
		if (offset + (duk_uint_t) field_bytelen > check_length) {
			goto fail_bounds;
		}

		/* Slow writing of value using either 64-bit arithmetic
		 * or IEEE doubles if 64-bit types not available.  There's
		 * no special sign handling when writing varints.
		 */

		if (magic_bigendian) {
			/* Write in big endian */
			i = field_bytelen;  /* one i_step added at top of loop */
			i_step = -1;
			i_end = 0;
		} else {
			/* Write in little endian */
			i = -1;  /* one i_step added at top of loop */
			i_step = 1;
			i_end = field_bytelen - 1;
		}

		/* XXX: The duk_to_number() cast followed by integer coercion
		 * is platform specific so NaN, +/- Infinity, and out-of-bounds
		 * values result in platform specific output now.
		 * See: test-bi-nodejs-buffer-proto-varint-special.js
		 */

#if defined(DUK_USE_64BIT_OPS)
		tmp = (duk_int64_t) duk_to_number(thr, 0);
		p = (duk_uint8_t *) (buf + offset);
		do {
			i += i_step;
			DUK_ASSERT(i >= 0 && i < field_bytelen);
			p[i] = (duk_uint8_t) (tmp & 0xff);
			tmp = tmp >> 8;  /* unnecessary shift for last byte */
		} while (i != i_end);
#else
		tmp = duk_to_number(thr, 0);
		p = (duk_uint8_t *) (buf + offset);
		do {
			i += i_step;
			tmp = DUK_FLOOR(tmp);
			DUK_ASSERT(i >= 0 && i < field_bytelen);
			p[i] = (duk_uint8_t) (DUK_FMOD(tmp, 256.0));
			tmp = tmp / 256.0;  /* unnecessary div for last byte */
		} while (i != i_end);
#endif
		break;
	}
	default: {  /* should never happen but default here */
		goto fail_bounds;
	}
	}

	/* Node.js Buffer: return offset + #bytes written (i.e. next
	 * write offset).
	 */
	if (magic_typedarray) {
		/* For TypedArrays 'undefined' return value is specified
		 * by ES2015 (matches V8).
		 */
		return 0;
	}
	duk_push_uint(thr, offset + (duk_uint_t) nbytes);
	return 1;

 fail_neutered:
 fail_field_length:
 fail_bounds:
	if (no_assert) {
		/* Node.js return value for failed writes is offset + #bytes
		 * that would have been written.
		 */
		/* XXX: for negative input offsets, 'offset' will be a large
		 * positive value so the result here is confusing.
		 */
		if (magic_typedarray) {
			return 0;
		}
		duk_push_uint(thr, offset + (duk_uint_t) nbytes);
		return 1;
	}
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  Accessors for .buffer, .byteLength, .byteOffset
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_LOCAL duk_hbufobj *duk__autospawn_arraybuffer(duk_hthread *thr, duk_hbuffer *h_buf) {
	duk_hbufobj *h_res;

	h_res = duk_push_bufobj_raw(thr,
	                            DUK_HOBJECT_FLAG_EXTENSIBLE |
	                            DUK_HOBJECT_FLAG_BUFOBJ |
	                            DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARRAYBUFFER),
	                            DUK_BIDX_ARRAYBUFFER_PROTOTYPE);
	DUK_ASSERT(h_res != NULL);
	DUK_UNREF(h_res);

	duk__set_bufobj_buffer(thr, h_res, h_buf);
	DUK_HBUFOBJ_ASSERT_VALID(h_res);
	DUK_ASSERT(h_res->buf_prop == NULL);
	return h_res;
}

DUK_INTERNAL duk_ret_t duk_bi_typedarray_buffer_getter(duk_hthread *thr) {
	duk_hbufobj *h_bufobj;

	h_bufobj = (duk_hbufobj *) duk__getrequire_bufobj_this(thr, DUK__BUFOBJ_FLAG_THROW /*flags*/);
	DUK_ASSERT(h_bufobj != NULL);
	if (DUK_HEAPHDR_IS_BUFFER((duk_heaphdr *) h_bufobj)) {
		DUK_DD(DUK_DDPRINT("autospawn ArrayBuffer for plain buffer"));
		(void) duk__autospawn_arraybuffer(thr, (duk_hbuffer *) h_bufobj);
		return 1;
	} else {
		if (h_bufobj->buf_prop == NULL &&
		    DUK_HOBJECT_GET_CLASS_NUMBER((duk_hobject *) h_bufobj) != DUK_HOBJECT_CLASS_ARRAYBUFFER &&
		    h_bufobj->buf != NULL) {
			duk_hbufobj *h_arrbuf;

			DUK_DD(DUK_DDPRINT("autospawn ArrayBuffer for typed array or DataView"));
			h_arrbuf = duk__autospawn_arraybuffer(thr, h_bufobj->buf);

			if (h_bufobj->buf_prop == NULL) {
				/* Must recheck buf_prop, in case ArrayBuffer
				 * alloc had a side effect which already filled
				 * it!
				 */

				/* Set ArrayBuffer's .byteOffset and .byteLength based
				 * on the view so that Arraybuffer[view.byteOffset]
				 * matches view[0].
				 */
				h_arrbuf->offset = 0;
				DUK_ASSERT(h_bufobj->offset + h_bufobj->length >= h_bufobj->offset);  /* Wrap check on creation. */
				h_arrbuf->length = h_bufobj->offset + h_bufobj->length;
				DUK_ASSERT(h_arrbuf->buf_prop == NULL);

				DUK_ASSERT(h_bufobj->buf_prop == NULL);
				h_bufobj->buf_prop = (duk_hobject *) h_arrbuf;
				DUK_HBUFOBJ_INCREF(thr, h_arrbuf);  /* Now reachable and accounted for. */
			}

			/* Left on stack; pushed for the second time below (OK). */
		}
		if (h_bufobj->buf_prop) {
			duk_push_hobject(thr, h_bufobj->buf_prop);
			return 1;
		}
	}
	return 0;
}

DUK_INTERNAL duk_ret_t duk_bi_typedarray_byteoffset_getter(duk_hthread *thr) {
	duk_hbufobj *h_bufobj;

	h_bufobj = (duk_hbufobj *) duk__getrequire_bufobj_this(thr, DUK__BUFOBJ_FLAG_THROW /*flags*/);
	DUK_ASSERT(h_bufobj != NULL);
	if (DUK_HEAPHDR_IS_BUFFER((duk_heaphdr *) h_bufobj)) {
		duk_push_uint(thr, 0);
	} else {
		/* If neutered must return 0; offset is zeroed during
		 * neutering.
		 */
		duk_push_uint(thr, h_bufobj->offset);
	}
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_typedarray_bytelength_getter(duk_hthread *thr) {
	duk_hbufobj *h_bufobj;

	h_bufobj = (duk_hbufobj *) duk__getrequire_bufobj_this(thr, DUK__BUFOBJ_FLAG_THROW /*flags*/);
	DUK_ASSERT(h_bufobj != NULL);
	if (DUK_HEAPHDR_IS_BUFFER((duk_heaphdr *) h_bufobj)) {
		duk_hbuffer *h_buf;

		h_buf = (duk_hbuffer *) h_bufobj;
		DUK_ASSERT(DUK_HBUFFER_GET_SIZE(h_buf) <= DUK_UINT_MAX);  /* Buffer limits. */
		duk_push_uint(thr, (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_buf));
	} else {
		/* If neutered must return 0; length is zeroed during
		 * neutering.
		 */
		duk_push_uint(thr, h_bufobj->length);
	}
	return 1;
}
#else  /* DUK_USE_BUFFEROBJECT_SUPPORT */
/* No .buffer getter without ArrayBuffer support. */
#if 0
DUK_INTERNAL duk_ret_t duk_bi_typedarray_buffer_getter(duk_hthread *thr) {
	return 0;
}
#endif

DUK_INTERNAL duk_ret_t duk_bi_typedarray_byteoffset_getter(duk_hthread *thr) {
	duk_push_uint(thr, 0);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_typedarray_bytelength_getter(duk_hthread *thr) {
	duk_hbuffer *h_buf;

	/* XXX: helper? */
	duk_push_this(thr);
	h_buf = duk_require_hbuffer(thr, -1);
	duk_push_uint(thr, DUK_HBUFFER_GET_SIZE(h_buf));
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/* automatic undefs */
#undef DUK__BUFOBJ_FLAG_PROMOTE
#undef DUK__BUFOBJ_FLAG_THROW
#undef DUK__FLD_16BIT
#undef DUK__FLD_32BIT
#undef DUK__FLD_8BIT
#undef DUK__FLD_BIGENDIAN
#undef DUK__FLD_DOUBLE
#undef DUK__FLD_FLOAT
#undef DUK__FLD_SIGNED
#undef DUK__FLD_TYPEDARRAY
#undef DUK__FLD_VARINT
/*
 *  CBOR bindings.
 *
 *  http://cbor.io/
 *  https://tools.ietf.org/html/rfc7049
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_CBOR_SUPPORT)

/* #define DUK_CBOR_STRESS */

/* Default behavior for encoding strings: use CBOR text string if string
 * is UTF-8 compatible, otherwise use CBOR byte string.  These defines
 * can be used to force either type for all strings.  Using text strings
 * for non-UTF-8 data is technically invalid CBOR.
 */
/* #define DUK_CBOR_TEXT_STRINGS */
/* #define DUK_CBOR_BYTE_STRINGS */

/* Misc. defines. */
/* #define DUK_CBOR_PREFER_SIZE */
/* #define DUK_CBOR_DOUBLE_AS_IS */
/* #define DUK_CBOR_DECODE_FASTPATH */

typedef struct {
	duk_hthread *thr;
	duk_uint8_t *ptr;
	duk_uint8_t *buf;
	duk_uint8_t *buf_end;
	duk_size_t len;
	duk_idx_t idx_buf;
} duk_cbor_encode_context;

typedef struct {
	duk_hthread *thr;
	const duk_uint8_t *buf;
	duk_size_t off;
	duk_size_t len;
} duk_cbor_decode_context;

DUK_LOCAL void duk__cbor_encode_value(duk_cbor_encode_context *enc_ctx);
DUK_LOCAL void duk__cbor_decode_value(duk_cbor_decode_context *dec_ctx);

/*
 *  Misc
 */

DUK_LOCAL duk_uint32_t duk__cbor_double_to_uint32(double d) {
	/* Out of range casts are undefined behavior, so caller must avoid. */
	DUK_ASSERT(d >= 0.0 && d <= 4294967295.0);
	return (duk_uint32_t) d;
}

/*
 *  Encoding
 */

DUK_LOCAL void duk__cbor_encode_error(duk_cbor_encode_context *enc_ctx) {
	(void) duk_type_error(enc_ctx->thr, "cbor encode error");
}

/* Check that a size_t is in uint32 range to avoid out-of-range casts. */
DUK_LOCAL void duk__cbor_encode_sizet_uint32_check(duk_cbor_encode_context *enc_ctx, duk_size_t len) {
	if (DUK_UNLIKELY(sizeof(duk_size_t) > sizeof(duk_uint32_t) && len > (duk_size_t) DUK_UINT32_MAX)) {
		duk__cbor_encode_error(enc_ctx);
	}
}

DUK_LOCAL DUK_NOINLINE void duk__cbor_encode_ensure_slowpath(duk_cbor_encode_context *enc_ctx, duk_size_t len) {
	duk_size_t oldlen;
	duk_size_t minlen;
	duk_size_t newlen;
	duk_uint8_t *p_new;
	duk_size_t old_data_len;

	DUK_ASSERT(enc_ctx->ptr >= enc_ctx->buf);
	DUK_ASSERT(enc_ctx->buf_end >= enc_ctx->ptr);
	DUK_ASSERT(enc_ctx->buf_end >= enc_ctx->buf);

	/* Overflow check.
	 *
	 * Limit example: 0xffffffffUL / 2U = 0x7fffffffUL, we reject >= 0x80000000UL.
	 */
	oldlen = enc_ctx->len;
	minlen = oldlen + len;
	if (DUK_UNLIKELY(oldlen > DUK_SIZE_MAX / 2U || minlen < oldlen)) {
		duk__cbor_encode_error(enc_ctx);
	}

#if defined(DUK_CBOR_STRESS)
	newlen = oldlen + 1U;
#else
	newlen = oldlen * 2U;
#endif
	DUK_ASSERT(newlen >= oldlen);

	if (minlen > newlen) {
		newlen = minlen;
	}
	DUK_ASSERT(newlen >= oldlen);
	DUK_ASSERT(newlen >= minlen);
	DUK_ASSERT(newlen > 0U);

	DUK_DD(DUK_DDPRINT("cbor encode buffer resized to %ld", (long) newlen));

	p_new = (duk_uint8_t *) duk_resize_buffer(enc_ctx->thr, enc_ctx->idx_buf, newlen);
	DUK_ASSERT(p_new != NULL);
	old_data_len = (duk_size_t) (enc_ctx->ptr - enc_ctx->buf);
	enc_ctx->buf = p_new;
	enc_ctx->buf_end = p_new + newlen;
	enc_ctx->ptr = p_new + old_data_len;
	enc_ctx->len = newlen;
}

DUK_LOCAL DUK_INLINE void duk__cbor_encode_ensure(duk_cbor_encode_context *enc_ctx, duk_size_t len) {
	if (DUK_LIKELY((duk_size_t) (enc_ctx->buf_end - enc_ctx->ptr) >= len)) {
		return;
	}
	duk__cbor_encode_ensure_slowpath(enc_ctx, len);
}

DUK_LOCAL duk_size_t duk__cbor_get_reserve(duk_cbor_encode_context *enc_ctx) {
	DUK_ASSERT(enc_ctx->ptr >= enc_ctx->buf);
	DUK_ASSERT(enc_ctx->ptr <= enc_ctx->buf_end);
	return (duk_size_t) (enc_ctx->buf_end - enc_ctx->ptr);
}

DUK_LOCAL void duk__cbor_encode_uint32(duk_cbor_encode_context *enc_ctx, duk_uint32_t u, duk_uint8_t base) {
	duk_uint8_t *p;

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 4);

	p = enc_ctx->ptr;
	if (DUK_LIKELY(u <= 23U)) {
		*p++ = (duk_uint8_t) (base + (duk_uint8_t) u);
	} else if (u <= 0xffUL) {
		*p++ = base + 0x18U;
		*p++ = (duk_uint8_t) u;
	} else if (u <= 0xffffUL) {
		*p++ = base + 0x19U;
		DUK_RAW_WRITEINC_U16_BE(p, (duk_uint16_t) u);
	} else {
		*p++ = base + 0x1aU;
		DUK_RAW_WRITEINC_U32_BE(p, u);
	}
	enc_ctx->ptr = p;
}

#if defined(DUK_CBOR_DOUBLE_AS_IS)
DUK_LOCAL void duk__cbor_encode_double(duk_cbor_encode_context *enc_ctx, double d) {
	duk_uint8_t *p;

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	p = enc_ctx->ptr;
	*p++ = 0xfbU;
	DUK_RAW_WRITEINC_DOUBLE_BE(p, d);
	p += 8;
	enc_ctx->ptr = p;
}
#else  /* DUK_CBOR_DOUBLE_AS_IS */
DUK_LOCAL void duk__cbor_encode_double_fp(duk_cbor_encode_context *enc_ctx, double d) {
	duk_double_union u;
	duk_uint16_t u16;
	duk_int16_t expt;
	duk_uint8_t *p;

	DUK_ASSERT(DUK_FPCLASSIFY(d) != DUK_FP_ZERO);

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	/* Organize into little endian (no-op if platform is little endian). */
	u.d = d;
	duk_dblunion_host_to_little(&u);

	/* Check if 'd' can represented as a normal half-float.
	 * Denormal half-floats could also be used, but that check
	 * isn't done now (denormal half-floats are decoded of course).
	 * So just check exponent range and that at most 10 significant
	 * bits (excluding implicit leading 1) are used in 'd'.
	 */
	u16 = (((duk_uint16_t) u.uc[7]) << 8) | ((duk_uint16_t) u.uc[6]);
	expt = (duk_int16_t) ((u16 & 0x7ff0U) >> 4) - 1023;

	if (expt >= -14 && expt <= 15) {
		/* Half-float normal exponents (excl. denormals).
		 *
		 *          7        6        5        4        3        2        1        0  (LE index)
		 * double: seeeeeee eeeemmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm
		 * half:         seeeee mmmm mmmmmm00 00000000 00000000 00000000 00000000 00000000
		 */
		duk_bool_t use_half_float;

		use_half_float =
		    (u.uc[0] == 0 && u.uc[1] == 0 && u.uc[2] == 0 && u.uc[3] == 0 &&
		     u.uc[4] == 0 && (u.uc[5] & 0x03U) == 0);

		if (use_half_float) {
			duk_uint32_t t;

			expt += 15;
			t = (duk_uint32_t) (u.uc[7] & 0x80U) << 8;
			t += (duk_uint32_t) expt << 10;
			t += ((duk_uint32_t) u.uc[6] & 0x0fU) << 6;
			t += ((duk_uint32_t) u.uc[5]) >> 2;

			/* seeeeemm mmmmmmmm */
			p = enc_ctx->ptr;
			*p++ = 0xf9U;
			DUK_RAW_WRITEINC_U16_BE(p, (duk_uint16_t) t);
			enc_ctx->ptr = p;
			return;
		}
	}

	/* Same check for plain float.  Also no denormal support here. */
	if (expt >= -126 && expt <= 127) {
		/* Float normal exponents (excl. denormals).
		 *
		 * double: seeeeeee eeeemmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm
		 * float:     seeee eeeemmmm mmmmmmmm mmmmmmmm mmm00000 00000000 00000000 00000000
		 */
		duk_bool_t use_float;
		duk_float_t d_float;

		/* We could do this explicit mantissa check, but doing
		 * a double-float-double cast is fine because we've
		 * already verified that the exponent is in range so
		 * that the narrower cast is not undefined behavior.
		 */
#if 0
		use_float =
		    (u.uc[0] == 0 && u.uc[1] == 0 && u.uc[2] == 0 && (u.uc[3] & 0xe0U) == 0);
#endif
		d_float = (duk_float_t) d;
		use_float = duk_double_equals((duk_double_t) d_float, d);
		if (use_float) {
			p = enc_ctx->ptr;
			*p++ = 0xfaU;
			DUK_RAW_WRITEINC_FLOAT_BE(p, d_float);
			enc_ctx->ptr = p;
			return;
		}
	}

	/* Special handling for NaN and Inf which we want to encode as
	 * half-floats.  They share the same (maximum) exponent.
	 */
	if (expt == 1024) {
		DUK_ASSERT(DUK_ISNAN(d) || DUK_ISINF(d));
		p = enc_ctx->ptr;
		*p++ = 0xf9U;
		if (DUK_ISNAN(d)) {
			/* Shortest NaN encoding is using a half-float.  Lose the
			 * exact NaN bits in the process.  IEEE double would be
			 * 7ff8 0000 0000 0000, i.e. a quiet NaN in most architectures
			 * (https://en.wikipedia.org/wiki/NaN#Encoding).  The
			 * equivalent half float is 7e00.
			 */
			*p++ = 0x7eU;
		} else {
			/* Shortest +/- Infinity encoding is using a half-float. */
			if (DUK_SIGNBIT(d)) {
				*p++ = 0xfcU;
			} else {
				*p++ = 0x7cU;
			}
		}
		*p++ = 0x00U;
		enc_ctx->ptr = p;
		return;
	}

	/* Cannot use half-float or float, encode as full IEEE double. */
	p = enc_ctx->ptr;
	*p++ = 0xfbU;
	DUK_RAW_WRITEINC_DOUBLE_BE(p, d);
	enc_ctx->ptr = p;
}

DUK_LOCAL void duk__cbor_encode_double(duk_cbor_encode_context *enc_ctx, double d) {
	duk_uint8_t *p;
	double d_floor;

	/* Integers and floating point values of all types are conceptually
	 * equivalent in CBOR.  Try to always choose the shortest encoding
	 * which is not always immediately obvious.  For example, NaN and Inf
	 * can be most compactly represented as a half-float (assuming NaN
	 * bits are not preserved), and 0x1'0000'0000 as a single precision
	 * float.  Shortest forms in preference order (prefer integer over
	 * float when equal length):
	 *
	 *   uint        1 byte    [0,23] (not -0)
	 *   sint        1 byte    [-24,-1]
	 *   uint+1      2 bytes   [24,255]
	 *   sint+1      2 bytes   [-256,-25]
	 *   uint+2      3 bytes   [256,65535]
	 *   sint+2      3 bytes   [-65536,-257]
	 *   half-float  3 bytes   -0, NaN, +/- Infinity, range [-65504,65504]
	 *   uint+4      5 bytes   [65536,4294967295]
	 *   sint+4      5 bytes   [-4294967296,-258]
	 *   float       5 bytes   range [-(1 - 2^(-24)) * 2^128, (1 - 2^(-24)) * 2^128]
	 *   uint+8      9 bytes   [4294967296,18446744073709551615]
	 *   sint+8      9 bytes   [-18446744073709551616,-4294967297]
	 *   double      9 bytes
	 *
	 * For whole numbers (compatible with integers):
	 *   - 1-byte or 2-byte uint/sint representation is preferred for
	 *     [-256,255].
	 *   - 3-byte uint/sint is preferred for [-65536,65535].  Half floats
	 *     are never preferred because they have the same length.
	 *   - 5-byte uint/sint is preferred for [-4294967296,4294967295].
	 *     Single precision floats are never preferred, and half-floats
	 *     don't reach above the 3-byte uint/sint range so they're never
	 *     preferred.
	 *   - So, for all integers up to signed/unsigned 32-bit range the
	 *     preferred encoding is always an integer uint/sint.
	 *   - For integers above 32 bits the situation is more complicated.
	 *     Half-floats are never useful for them because of their limited
	 *     range, but IEEE single precision floats (5 bytes encoded) can
	 *     represent some integers between the 32-bit and 64-bit ranges
	 *     which require 9 bytes as a uint/sint.
	 *
	 * For floating point values not compatible with integers, the
	 * preferred encoding is quite clear:
	 *   - For +Inf/-Inf use half-float.
	 *   - For NaN use a half-float, assuming NaN bits ("payload") is
	 *     not worth preserving.  Duktape doesn't in general guarantee
	 *     preservation of the NaN payload so using a half-float seems
	 *     consistent with that.
	 *   - For remaining values, prefer the shortest form which doesn't
	 *     lose any precision.  For normal half-floats and single precision
	 *     floats this is simple: just check exponent and mantissa bits
	 *     using a fixed mask.  For denormal half-floats and single
	 *     precision floats the check is a bit more complicated: a normal
	 *     IEEE double can sometimes be represented as a denormal
	 *     half-float or single precision float.
	 *
	 * https://en.wikipedia.org/wiki/Half-precision_floating-point_format#IEEE_754_half-precision_binary_floating-point_format:_binary16
	 */

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	/* Most important path is integers.  The floor() test will be true
	 * for Inf too (but not NaN).
	 */
	d_floor = DUK_FLOOR(d);  /* identity if d is +/- 0.0, NaN, or +/- Infinity */
	if (DUK_LIKELY(duk_double_equals(d_floor, d) != 0)) {
		DUK_ASSERT(!DUK_ISNAN(d));  /* NaN == NaN compares false. */
		if (DUK_SIGNBIT(d)) {
			if (d >= -4294967296.0) {
				d = -1.0 - d;
				if (d >= 0.0) {
					DUK_ASSERT(d >= 0.0);
					duk__cbor_encode_uint32(enc_ctx, duk__cbor_double_to_uint32(d), 0x20U);
					return;
				}

				/* Input was negative zero, d == -1.0 < 0.0.
				 * Shortest -0 is using half-float.
				 */
				p = enc_ctx->ptr;
				*p++ = 0xf9U;
				*p++ = 0x80U;
				*p++ = 0x00U;
				enc_ctx->ptr = p;
				return;
			}
		} else {
			if (d <= 4294967295.0) {
				/* Positive zero needs no special handling. */
				DUK_ASSERT(d >= 0.0);
				duk__cbor_encode_uint32(enc_ctx, duk__cbor_double_to_uint32(d), 0x00U);
				return;
			}
		}
	}

	/* 64-bit integers are not supported at present.  So
	 * we also don't need to deal with choosing between a
	 * 64-bit uint/sint representation vs. IEEE double or
	 * float.
	 */

	DUK_ASSERT(DUK_FPCLASSIFY(d) != DUK_FP_ZERO);
	duk__cbor_encode_double_fp(enc_ctx, d);
}
#endif  /* DUK_CBOR_DOUBLE_AS_IS */

DUK_LOCAL void duk__cbor_encode_string_top(duk_cbor_encode_context *enc_ctx) {
	const duk_uint8_t *str;
	duk_size_t len;
	duk_uint8_t *p;

	/* CBOR differentiates between UTF-8 text strings and byte strings.
	 * Text strings MUST be valid UTF-8, so not all Duktape strings can
	 * be encoded as valid CBOR text strings.  Possible behaviors:
	 *
	 *   1. Use text string when input is valid UTF-8, otherwise use
	 *      byte string (maybe tagged to indicate it was an extended
	 *      UTF-8 string).
	 *   2. Always use text strings, but sanitize input string so that
	 *      invalid UTF-8 is replaced with U+FFFD for example.  Combine
	 *      surrogates whenever possible.
	 *   3. Always use byte strings.  This is simple and produces valid
	 *      CBOR, but isn't ideal for interoperability.
	 *   4. Always use text strings, even for invalid UTF-8 such as
	 *      codepoints in the surrogate pair range.  This is simple but
	 *      produces technically invalid CBOR for non-UTF-8 strings which
	 *      may affect interoperability.
	 *
	 * Current default is 1; can be changed with defines.
	 */

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	str = (const duk_uint8_t *) duk_require_lstring(enc_ctx->thr, -1, &len);
	if (duk_is_symbol(enc_ctx->thr, -1)) {
		/* Symbols, encode as an empty table for now.  This matches
		 * the behavior of cbor-js.
		 *
		 * XXX: Maybe encode String() coercion with a tag?
		 * XXX: Option to keep enough information to recover
		 * Symbols when decoding (this is not always desirable).
		 */
		p = enc_ctx->ptr;
		*p++ = 0xa0U;
		enc_ctx->ptr = p;
		return;
	}

	duk__cbor_encode_sizet_uint32_check(enc_ctx, len);
#if defined(DUK_CBOR_TEXT_STRINGS)
	duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len, 0x60U);
#elif defined(DUK_CBOR_BYTE_STRINGS)
	duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len, 0x40U);
#else
	duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len,
	                        (DUK_LIKELY(duk_unicode_is_utf8_compatible(str, len) != 0) ? 0x60U : 0x40U));
#endif
	duk__cbor_encode_ensure(enc_ctx, len);
	p = enc_ctx->ptr;
	duk_memcpy((void *) p, (const void *) str, len);
	p += len;
	enc_ctx->ptr = p;
}

DUK_LOCAL void duk__cbor_encode_object(duk_cbor_encode_context *enc_ctx) {
	duk_uint8_t *buf;
	duk_size_t len;
	duk_uint8_t *p;
	duk_size_t i;
	duk_size_t off_ib;
	duk_uint32_t count;

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	/* XXX: Support for specific built-ins like Date and RegExp. */
	if (duk_is_array(enc_ctx->thr, -1)) {
		/* Shortest encoding for arrays >= 256 in length is actually
		 * the indefinite length one (3 or more bytes vs. 2 bytes).
		 * We still use the definite length version because it is
		 * more decoding friendly.
		 */
		len = duk_get_length(enc_ctx->thr, -1);
		duk__cbor_encode_sizet_uint32_check(enc_ctx, len);
		duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len, 0x80U);
		for (i = 0; i < len; i++) {
			duk_get_prop_index(enc_ctx->thr, -1, (duk_uarridx_t) i);
			duk__cbor_encode_value(enc_ctx);
		}
	} else if (duk_is_buffer_data(enc_ctx->thr, -1)) {
		/* XXX: Tag buffer data?
		 * XXX: Encode typed arrays as integer arrays rather
		 * than buffer data as is?
		 */
		buf = (duk_uint8_t *) duk_require_buffer_data(enc_ctx->thr, -1, &len);
		duk__cbor_encode_sizet_uint32_check(enc_ctx, len);
		duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len, 0x40U);
		duk__cbor_encode_ensure(enc_ctx, len);
		p = enc_ctx->ptr;
		duk_memcpy((void *) p, (const void *) buf, len);
		p += len;
		enc_ctx->ptr = p;
	} else {
		/* We don't know the number of properties in advance
		 * but would still like to encode at least small
		 * objects without indefinite length.  Emit an
		 * indefinite length byte initially, and if the final
		 * property count is small enough to also fit in one
		 * byte, backpatch it later.  Otherwise keep the
		 * indefinite length.  This works well up to 23
		 * properties which is practical and good enough.
		 */
		off_ib = (duk_size_t) (enc_ctx->ptr - enc_ctx->buf);  /* XXX: get_offset? */
		count = 0U;
		p = enc_ctx->ptr;
		*p++ = 0xa0U + 0x1fU;  /* indefinite length */
		enc_ctx->ptr = p;
		duk_enum(enc_ctx->thr, -1, DUK_ENUM_OWN_PROPERTIES_ONLY);
		while (duk_next(enc_ctx->thr, -1, 1 /*get_value*/)) {
			duk_insert(enc_ctx->thr, -2);  /* [ ... key value ] -> [ ... value key ] */
			duk__cbor_encode_value(enc_ctx);
			duk__cbor_encode_value(enc_ctx);
			count++;
			if (count == 0U) {
				duk__cbor_encode_error(enc_ctx);
			}
		}
		duk_pop(enc_ctx->thr);
		if (count <= 0x17U) {
			DUK_ASSERT(off_ib < enc_ctx->len);
			enc_ctx->buf[off_ib] = 0xa0U + (duk_uint8_t) count;
		} else {
			duk__cbor_encode_ensure(enc_ctx, 1);
			p = enc_ctx->ptr;
			*p++ = 0xffU;  /* break */
			enc_ctx->ptr = p;
		}
	}
}

DUK_LOCAL void duk__cbor_encode_buffer(duk_cbor_encode_context *enc_ctx) {
	duk_uint8_t *buf;
	duk_size_t len;
	duk_uint8_t *p;

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	/* Tag buffer data? */
	buf = (duk_uint8_t *) duk_require_buffer(enc_ctx->thr, -1, &len);
	duk__cbor_encode_sizet_uint32_check(enc_ctx, len);
	duk__cbor_encode_uint32(enc_ctx, (duk_uint32_t) len, 0x40U);
	duk__cbor_encode_ensure(enc_ctx, len);
	p = enc_ctx->ptr;
	duk_memcpy((void *) p, (const void *) buf, len);
	p += len;
	enc_ctx->ptr = p;
}

DUK_LOCAL void duk__cbor_encode_pointer(duk_cbor_encode_context *enc_ctx) {
	/* Pointers (void *) are challenging to encode.  They can't
	 * be relied to be even 64-bit integer compatible (there are
	 * pointer models larger than that), nor can floats encode
	 * them.  They could be encoded as strings (%p format) but
	 * that's not portable.  They could be encoded as direct memory
	 * representations.  Recovering pointers is non-portable in any
	 * case but it would be nice to be able to detect and recover
	 * compatible pointers.
	 *
	 * For now, encode as "(%p)" string, matching JX.  There doesn't
	 * seem to be an appropriate tag, so pointers don't currently
	 * survive a CBOR encode/decode roundtrip intact.
	 */
	const char *ptr;

	ptr = duk_to_string(enc_ctx->thr, -1);
	DUK_ASSERT(ptr != NULL);
	duk_push_sprintf(enc_ctx->thr, "(%s)", ptr);
	duk_remove(enc_ctx->thr, -2);
	duk__cbor_encode_string_top(enc_ctx);
}

DUK_LOCAL void duk__cbor_encode_lightfunc(duk_cbor_encode_context *enc_ctx) {
	duk_uint8_t *p;

	/* Caller must ensure space. */
	DUK_ASSERT(duk__cbor_get_reserve(enc_ctx) >= 1 + 8);

	/* For now encode as an empty object. */
	p = enc_ctx->ptr;
	*p++ = 0xa0U;
	enc_ctx->ptr = p;
}

DUK_LOCAL void duk__cbor_encode_value(duk_cbor_encode_context *enc_ctx) {
	duk_uint8_t *p;

	/* Encode/decode cycle currently loses some type information.
	 * This can be improved by registering custom tags with IANA.
	 */

	/* When working with deeply recursive structures, this is important
	 * to ensure there's no effective depth limit.
	 */
	duk_require_stack(enc_ctx->thr, 4);

	/* Reserve space for up to 64-bit types (1 initial byte + 8
	 * followup bytes).  This allows encoding of integers, floats,
	 * string/buffer length fields, etc without separate checks
	 * in each code path.
	 */
	duk__cbor_encode_ensure(enc_ctx, 1 + 8);

	switch (duk_get_type(enc_ctx->thr, -1)) {
	case DUK_TYPE_UNDEFINED: {
		p = enc_ctx->ptr;
		*p++ = 0xf7;
		enc_ctx->ptr = p;
		break;
	}
	case DUK_TYPE_NULL: {
		p = enc_ctx->ptr;
		*p++ = 0xf6;
		enc_ctx->ptr = p;
		break;
	}
	case DUK_TYPE_BOOLEAN: {
		duk_uint8_t u8 = duk_get_boolean(enc_ctx->thr, -1) ? 0xf5U : 0xf4U;
		p = enc_ctx->ptr;
		*p++ = u8;
		enc_ctx->ptr = p;
		break;
	}
	case DUK_TYPE_NUMBER: {
		duk__cbor_encode_double(enc_ctx, duk_get_number(enc_ctx->thr, -1));
		break;
	}
	case DUK_TYPE_STRING: {
		duk__cbor_encode_string_top(enc_ctx);
		break;
	}
	case DUK_TYPE_OBJECT: {
		duk__cbor_encode_object(enc_ctx);
		break;
	}
	case DUK_TYPE_BUFFER: {
		duk__cbor_encode_buffer(enc_ctx);
		break;
	}
	case DUK_TYPE_POINTER: {
		duk__cbor_encode_pointer(enc_ctx);
		break;
	}
	case DUK_TYPE_LIGHTFUNC: {
		duk__cbor_encode_lightfunc(enc_ctx);
		break;
	}
	case DUK_TYPE_NONE:
	default:
		goto fail;
	}

	duk_pop(enc_ctx->thr);
	return;

 fail:
	duk__cbor_encode_error(enc_ctx);
}

/*
 *  Decoding
 */

DUK_LOCAL void duk__cbor_req_stack(duk_cbor_decode_context *dec_ctx) {
	duk_require_stack(dec_ctx->thr, 4);
}

DUK_LOCAL void duk__cbor_decode_error(duk_cbor_decode_context *dec_ctx) {
	(void) duk_type_error(dec_ctx->thr, "cbor decode error");
}

DUK_LOCAL duk_uint8_t duk__cbor_decode_readbyte(duk_cbor_decode_context *dec_ctx) {
	DUK_ASSERT(dec_ctx->off <= dec_ctx->len);
	if (DUK_UNLIKELY(dec_ctx->len - dec_ctx->off < 1U)) {
		duk__cbor_decode_error(dec_ctx);
	}
	return dec_ctx->buf[dec_ctx->off++];
}

DUK_LOCAL duk_uint16_t duk__cbor_decode_read_u16(duk_cbor_decode_context *dec_ctx) {
	duk_uint16_t res;

	DUK_ASSERT(dec_ctx->off <= dec_ctx->len);
	if (DUK_UNLIKELY(dec_ctx->len - dec_ctx->off < 2U)) {
		duk__cbor_decode_error(dec_ctx);
	}
	res = DUK_RAW_READ_U16_BE(dec_ctx->buf + dec_ctx->off);
	dec_ctx->off += 2;
	return res;
}

DUK_LOCAL duk_uint32_t duk__cbor_decode_read_u32(duk_cbor_decode_context *dec_ctx) {
	duk_uint32_t res;

	DUK_ASSERT(dec_ctx->off <= dec_ctx->len);
	if (DUK_UNLIKELY(dec_ctx->len - dec_ctx->off < 4U)) {
		duk__cbor_decode_error(dec_ctx);
	}
	res = DUK_RAW_READ_U32_BE(dec_ctx->buf + dec_ctx->off);
	dec_ctx->off += 4;
	return res;
}

DUK_LOCAL duk_uint8_t duk__cbor_decode_peekbyte(duk_cbor_decode_context *dec_ctx) {
	if (DUK_UNLIKELY(dec_ctx->off >= dec_ctx->len)) {
		duk__cbor_decode_error(dec_ctx);
	}
	return dec_ctx->buf[dec_ctx->off];
}

DUK_LOCAL void duk__cbor_decode_rewind(duk_cbor_decode_context *dec_ctx, duk_size_t len) {
	DUK_ASSERT(len <= dec_ctx->off);  /* Caller must ensure. */
	dec_ctx->off -= len;
}

#if 0
DUK_LOCAL void duk__cbor_decode_ensure(duk_cbor_decode_context *dec_ctx, duk_size_t len) {
	if (dec_ctx->off + len > dec_ctx->len) {
		duk__cbor_decode_error(dec_ctx);
	}
}
#endif

DUK_LOCAL const duk_uint8_t *duk__cbor_decode_consume(duk_cbor_decode_context *dec_ctx, duk_size_t len) {
	DUK_ASSERT(dec_ctx->off <= dec_ctx->len);
	if (DUK_LIKELY(dec_ctx->len - dec_ctx->off >= len)) {
		const duk_uint8_t *res = dec_ctx->buf + dec_ctx->off;
		dec_ctx->off += len;
		return res;
	}

	duk__cbor_decode_error(dec_ctx);  /* Not enough input. */
	return NULL;
}

DUK_LOCAL int duk__cbor_decode_checkbreak(duk_cbor_decode_context *dec_ctx) {
	if (duk__cbor_decode_peekbyte(dec_ctx) == 0xffU) {
		DUK_ASSERT(dec_ctx->off < dec_ctx->len);
		dec_ctx->off++;
#if 0
		(void) duk__cbor_decode_readbyte(dec_ctx);
#endif
		return 1;
	}
	return 0;
}

DUK_LOCAL void duk__cbor_decode_push_aival_int(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib, duk_bool_t negative) {
	duk_uint8_t ai;
	duk_uint32_t t, t1, t2;
#if 0
	duk_uint64_t t3;
#endif
	duk_double_t d1, d2;
	duk_double_t d;

	ai = ib & 0x1fU;
	if (ai <= 0x17U) {
		t = ai;
		goto shared_exit;
	}

	switch (ai) {
	case 0x18U:  /* 1 byte */
		t = (duk_uint32_t) duk__cbor_decode_readbyte(dec_ctx);
		goto shared_exit;
	case 0x19U:  /* 2 byte */
		t = (duk_uint32_t) duk__cbor_decode_read_u16(dec_ctx);
		goto shared_exit;
	case 0x1aU:  /* 4 byte */
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		goto shared_exit;
	case 0x1bU:  /* 8 byte */
		/* For uint64 it's important to handle the -1.0 part before
		 * casting to double: otherwise the adjustment might be lost
		 * in the cast.  Uses: -1.0 - d <=> -(d + 1.0).
		 */
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		t2 = t;
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		t1 = t;
#if 0
		t3 = (duk_uint64_t) t2 * DUK_U64_CONSTANT(0x100000000) + (duk_uint64_t) t1;
		if (negative) {
			if (t3 == DUK_UINT64_MAX) {
				/* -(0xffff'ffff'ffff'ffffULL + 1) =
				 * -0x1'0000'0000'0000'0000
				 *
				 * >>> -0x10000000000000000
				 * -18446744073709551616L
				 */
				return -18446744073709551616.0;
			} else {
				return -((duk_double_t) (t3 + DUK_U64_CONSTANT(1)));
			}
		} else {
			return (duk_double_t) t3;  /* XXX: cast helper */
		}
#endif
#if 0
		t3 = (duk_uint64_t) t2 * DUK_U64_CONSTANT(0x100000000) + (duk_uint64_t) t1;
		if (negative) {
			/* Simpler version: take advantage of the fact that
			 * 0xffff'ffff'ffff'ffff and 0x1'0000'0000'0000'0000
			 * both round to 0x1'0000'0000'0000'0000:
			 * > (0xffffffffffffffff).toString(16)
			 * '10000000000000000'
			 * > (0x10000000000000000).toString(16)
			 * '10000000000000000'
			 *
			 * For the DUK_UINT64_MAX case we just skip the +1
			 * increment to avoid wrapping; the result still
			 * comes out right for an IEEE double cast.
			 */
			if (t3 != DUK_UINT64_MAX) {
				t3++;
			}
			return -((duk_double_t) t3);
		} else {
			return (duk_double_t) t3;  /* XXX: cast helper */
		}
#endif
#if 1
		/* Use two double parts, avoids dependency on 64-bit type.
		 * Avoid precision loss carefully, especially when dealing
		 * with the required +1 for negative values.
		 *
		 * No fastint check for this path at present.
		 */
		d1 = (duk_double_t) t1;  /* XXX: cast helpers */
		d2 = (duk_double_t) t2 * 4294967296.0;
		if (negative) {
			d1 += 1.0;
		}
		d = d2 + d1;
		if (negative) {
			d = -d;
		}
#endif
		/* XXX: a push and check for fastint API would be nice */
		duk_push_number(dec_ctx->thr, d);
		return;
	}

	duk__cbor_decode_error(dec_ctx);
	return;

 shared_exit:
	if (negative) {
		/* XXX: a push and check for fastint API would be nice */
		if ((duk_uint_t) t <= (duk_uint_t) -(DUK_INT_MIN + 1)) {
			duk_push_int(dec_ctx->thr, -1 - ((duk_int_t) t));
		} else {
			duk_push_number(dec_ctx->thr, -1.0 - (duk_double_t) t);
		}
	} else {
		duk_push_uint(dec_ctx->thr, (duk_uint_t) t);
	}
}

DUK_LOCAL void duk__cbor_decode_skip_aival_int(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib) {
	const duk_int8_t skips[32] = {
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 8, -1, -1, -1, -1
	};
	duk_uint8_t ai;
	duk_int8_t skip;

	ai = ib & 0x1fU;
	skip = skips[ai];
	if (DUK_UNLIKELY(skip < 0)) {
		duk__cbor_decode_error(dec_ctx);
	}
	duk__cbor_decode_consume(dec_ctx, (duk_size_t) skip);
	return;
}

DUK_LOCAL duk_uint32_t duk__cbor_decode_aival_uint32(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib) {
	duk_uint8_t ai;
	duk_uint32_t t;

	ai = ib & 0x1fU;
	if (ai <= 0x17U) {
		return (duk_uint32_t) ai;
	}

	switch (ai) {
	case 0x18U:  /* 1 byte */
		t = (duk_uint32_t) duk__cbor_decode_readbyte(dec_ctx);
		return t;
	case 0x19U:  /* 2 byte */
		t = (duk_uint32_t) duk__cbor_decode_read_u16(dec_ctx);
		return t;
	case 0x1aU:  /* 4 byte */
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		return t;
	case 0x1bU:  /* 8 byte */
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		if (t != 0U) {
			break;
		}
		t = (duk_uint32_t) duk__cbor_decode_read_u32(dec_ctx);
		return t;
	}

	duk__cbor_decode_error(dec_ctx);
	return 0U;
}

DUK_LOCAL void duk__cbor_decode_buffer(duk_cbor_decode_context *dec_ctx, duk_uint8_t expected_base) {
	duk_uint32_t len;
	duk_uint8_t *buf;
	const duk_uint8_t *inp;
	duk_uint8_t ib;

	ib = duk__cbor_decode_readbyte(dec_ctx);
	if ((ib & 0xe0U) != expected_base) {
		duk__cbor_decode_error(dec_ctx);
	}
	/* Indefinite format is rejected by the following on purpose. */
	len = duk__cbor_decode_aival_uint32(dec_ctx, ib);
	inp = duk__cbor_decode_consume(dec_ctx, len);
	/* XXX: duk_push_fixed_buffer_with_data() would be a nice API addition. */
	buf = (duk_uint8_t *) duk_push_fixed_buffer(dec_ctx->thr, (duk_size_t) len);
	duk_memcpy((void *) buf, (const void *) inp, (size_t) len);
}

DUK_LOCAL void duk__cbor_decode_join_buffers(duk_cbor_decode_context *dec_ctx, duk_idx_t count) {
	duk_size_t total_size = 0;
	duk_idx_t top = duk_get_top(dec_ctx->thr);
	duk_idx_t base = top - count;  /* count is >= 1 */
	duk_idx_t idx;
	duk_uint8_t *p = NULL;

	DUK_ASSERT(count >= 1);
	DUK_ASSERT(top >= count);

	for (;;) {
		/* First round: compute total size.
		 * Second round: copy into place.
		 */
		for (idx = base; idx < top; idx++) {
			duk_uint8_t *buf_data;
			duk_size_t buf_size;

			buf_data = (duk_uint8_t *) duk_require_buffer(dec_ctx->thr, idx, &buf_size);
			if (p != NULL) {
				if (buf_size > 0U) {
					duk_memcpy((void *) p, (const void *) buf_data, buf_size);
				}
				p += buf_size;
			} else {
				total_size += buf_size;
				if (DUK_UNLIKELY(total_size < buf_size)) {  /* Wrap check. */
					duk__cbor_decode_error(dec_ctx);
				}
			}
		}

		if (p != NULL) {
			break;
		} else {
			p = (duk_uint8_t *) duk_push_fixed_buffer(dec_ctx->thr, total_size);
			DUK_ASSERT(p != NULL);
		}
	}

	duk_replace(dec_ctx->thr, base);
	duk_pop_n(dec_ctx->thr, count - 1);
}

DUK_LOCAL void duk__cbor_decode_and_join_strbuf(duk_cbor_decode_context *dec_ctx, duk_uint8_t expected_base) {
	duk_idx_t count = 0;
	for (;;) {
		if (duk__cbor_decode_checkbreak(dec_ctx)) {
			break;
		}
		duk_require_stack(dec_ctx->thr, 1);
		duk__cbor_decode_buffer(dec_ctx, expected_base);
		count++;
		if (DUK_UNLIKELY(count <= 0)) {  /* Wrap check. */
			duk__cbor_decode_error(dec_ctx);
		}
	}
	if (count == 0) {
		(void) duk_push_fixed_buffer(dec_ctx->thr, 0);
	} else if (count > 1) {
		duk__cbor_decode_join_buffers(dec_ctx, count);
	}
}

DUK_LOCAL duk_double_t duk__cbor_decode_half_float(duk_cbor_decode_context *dec_ctx) {
	duk_double_union u;
	const duk_uint8_t *inp;
	duk_int_t expt;
	duk_uint_t u16;
	duk_uint_t tmp;
	duk_double_t res;

	inp = duk__cbor_decode_consume(dec_ctx, 2);
	u16 = ((duk_uint_t) inp[0] << 8) + (duk_uint_t) inp[1];
	expt = (duk_int_t) ((u16 >> 10) & 0x1fU) - 15;

	/* Reconstruct IEEE double into little endian order first, then convert
	 * to host order.
	 */

	duk_memzero((void *) &u, sizeof(u));

	if (expt == -15) {
		/* Zero or denormal; but note that half float
		 * denormals become double normals.
		 */
		if ((u16 & 0x03ffU) == 0) {
			u.uc[7] = inp[0] & 0x80U;
		} else {
			/* Create denormal by first creating a double that
			 * contains the denormal bits and a leading implicit
			 * 1-bit.  Then subtract away the implicit 1-bit.
			 *
			 *    0.mmmmmmmmmm * 2^-14
			 *    1.mmmmmmmmmm 0.... * 2^-14
			 *   -1.0000000000 0.... * 2^-14
			 *
			 * Double exponent: -14 + 1023 = 0x3f1
			 */
			u.uc[7] = 0x3fU;
			u.uc[6] = 0x10U + (duk_uint8_t) ((u16 >> 6) & 0x0fU);
			u.uc[5] = (duk_uint8_t) ((u16 << 2) & 0xffU);  /* Mask is really 0xfcU */

			duk_dblunion_little_to_host(&u);
			res = u.d - 0.00006103515625;  /* 2^(-14) */
			if (u16 & 0x8000U) {
				res = -res;
			}
			return res;
		}
	} else if (expt == 16) {
		/* +/- Inf or NaN. */
		if ((u16 & 0x03ffU) == 0) {
			u.uc[7] = (inp[0] & 0x80U) + 0x7fU;
			u.uc[6] = 0xf0U;
		} else {
			/* Create a 'quiet NaN' with highest
			 * bit set (there are some platforms
			 * where the NaN payload convention is
			 * the opposite).  Keep sign.
			 */
			u.uc[7] = (inp[0] & 0x80U) + 0x7fU;
			u.uc[6] = 0xf8U;
		}
	} else {
		/* Normal. */
		tmp = (inp[0] & 0x80U) ? 0x80000000UL : 0UL;
		tmp += (duk_uint_t) (expt + 1023) << 20;
		tmp += (duk_uint_t) (inp[0] & 0x03U) << 18;
		tmp += (duk_uint_t) (inp[1] & 0xffU) << 10;
		u.uc[7] = (tmp >> 24) & 0xffU;
		u.uc[6] = (tmp >> 16) & 0xffU;
		u.uc[5] = (tmp >> 8) & 0xffU;
		u.uc[4] = (tmp >> 0) & 0xffU;
	}

	duk_dblunion_little_to_host(&u);
	return u.d;
}

DUK_LOCAL void duk__cbor_decode_string(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib, duk_uint8_t ai) {
	/* If the CBOR string data is not valid UTF-8 it is technically
	 * invalid CBOR.  Possible behaviors at least:
	 *
	 *   1. Reject the input, i.e. throw TypeError.
	 *
	 *   2. Accept the input, but sanitize non-UTF-8 data into UTF-8
	 *      using U+FFFD replacements.  Also it might make sense to
	 *      decode non-BMP codepoints into surrogates for better
	 *      ECMAScript compatibility.
	 *
	 *   3. Accept the input as a Duktape string (which are not always
	 *      valid UTF-8), but reject any input that would create a
	 *      Symbol representation.
	 *
	 * Current behavior is 3.
	 */

	if (ai == 0x1fU) {
		duk_uint8_t *buf_data;
		duk_size_t buf_size;

		duk__cbor_decode_and_join_strbuf(dec_ctx, 0x60U);
		buf_data = (duk_uint8_t *) duk_require_buffer(dec_ctx->thr, -1, &buf_size);
		(void) duk_push_lstring(dec_ctx->thr, (const char *) buf_data, buf_size);
		duk_remove(dec_ctx->thr, -2);
	} else {
		duk_uint32_t len;
		const duk_uint8_t *inp;

		len = duk__cbor_decode_aival_uint32(dec_ctx, ib);
		inp = duk__cbor_decode_consume(dec_ctx, len);
		(void) duk_push_lstring(dec_ctx->thr, (const char *) inp, (duk_size_t) len);
	}
	if (duk_is_symbol(dec_ctx->thr, -1)) {
		/* Refuse to create Symbols when decoding. */
		duk__cbor_decode_error(dec_ctx);
	}

	/* XXX: Here a Duktape API call to convert input -> utf-8 with
	 * replacements would be nice.
	 */
}

DUK_LOCAL duk_bool_t duk__cbor_decode_array(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib, duk_uint8_t ai) {
	duk_uint32_t idx, len;

	duk__cbor_req_stack(dec_ctx);

	/* Support arrays up to 0xfffffffeU in length.  0xffffffff is
	 * used as an indefinite length marker.
	 */
	if (ai == 0x1fU) {
		len = 0xffffffffUL;
	} else {
		len = duk__cbor_decode_aival_uint32(dec_ctx, ib);
		if (len == 0xffffffffUL) {
			return 0;
		}
	}

	/* XXX: use bare array? */
	duk_push_array(dec_ctx->thr);
	for (idx = 0U; ;) {
		if (len == 0xffffffffUL && duk__cbor_decode_checkbreak(dec_ctx)) {
			break;
		}
		if (idx == len) {
			if (ai == 0x1fU) {
				return 0;
			}
			break;
		}
		duk__cbor_decode_value(dec_ctx);
		duk_put_prop_index(dec_ctx->thr, -2, (duk_uarridx_t) idx);
		idx++;
		if (idx == 0U) {
			return 0;  /* wrapped */
		}
	}

	return 1;
}

DUK_LOCAL duk_bool_t duk__cbor_decode_map(duk_cbor_decode_context *dec_ctx, duk_uint8_t ib, duk_uint8_t ai) {
	duk_uint32_t count;

	duk__cbor_req_stack(dec_ctx);

	if (ai == 0x1fU) {
		count = 0xffffffffUL;
	} else {
		count = duk__cbor_decode_aival_uint32(dec_ctx, ib);
		if (count == 0xffffffffUL) {
			return 0;
		}
	}

	/* XXX: use bare object? */
	duk_push_object(dec_ctx->thr);
	for (;;) {
		if (count == 0xffffffffUL) {
			if (duk__cbor_decode_checkbreak(dec_ctx)) {
				break;
			}
		} else {
			if (count == 0UL) {
				break;
			}
			count--;
		}

		/* Non-string keys are coerced to strings,
		 * possibly leading to overwriting previous
		 * keys.  Last key of a certain coerced name
		 * wins.  If key is an object, it will coerce
		 * to '[object Object]' which is consistent
		 * but potentially misleading.  One alternative
		 * would be to skip non-string keys.
		 */
		duk__cbor_decode_value(dec_ctx);
		duk__cbor_decode_value(dec_ctx);
		duk_put_prop(dec_ctx->thr, -3);
	}

	return 1;
}

DUK_LOCAL duk_double_t duk__cbor_decode_float(duk_cbor_decode_context *dec_ctx) {
	duk_float_union u;
	const duk_uint8_t *inp;
	inp = duk__cbor_decode_consume(dec_ctx, 4);
	duk_memcpy((void *) u.uc, (const void *) inp, 4);
	duk_fltunion_big_to_host(&u);
	return (duk_double_t) u.f;
}

DUK_LOCAL duk_double_t duk__cbor_decode_double(duk_cbor_decode_context *dec_ctx) {
	duk_double_union u;
	const duk_uint8_t *inp;
	inp = duk__cbor_decode_consume(dec_ctx, 8);
	duk_memcpy((void *) u.uc, (const void *) inp, 8);
	duk_dblunion_big_to_host(&u);
	return u.d;
}

#if defined(DUK_CBOR_DECODE_FASTPATH)
#define DUK__CBOR_AI  (ib & 0x1fU)

DUK_LOCAL void duk__cbor_decode_value(duk_cbor_decode_context *dec_ctx) {
	duk_uint8_t ib;

	/* Any paths potentially recursing back to duk__cbor_decode_value()
	 * must perform a Duktape value stack growth check.  Avoid the check
	 * here for simple paths like primitive values.
	 */

 reread_initial_byte:
	DUK_DDD(DUK_DDDPRINT("cbor decode off=%ld len=%ld", (long) dec_ctx->off, (long) dec_ctx->len));

	ib = duk__cbor_decode_readbyte(dec_ctx);

	/* Full initial byte switch, footprint cost over baseline is ~+1kB. */
	/* XXX: Force full switch with no range check. */

	switch (ib) {
	case 0x00U: case 0x01U: case 0x02U: case 0x03U: case 0x04U: case 0x05U: case 0x06U: case 0x07U:
	case 0x08U: case 0x09U: case 0x0aU: case 0x0bU: case 0x0cU: case 0x0dU: case 0x0eU: case 0x0fU:
	case 0x10U: case 0x11U: case 0x12U: case 0x13U: case 0x14U: case 0x15U: case 0x16U: case 0x17U:
		duk_push_uint(dec_ctx->thr, ib);
		break;
	case 0x18U: case 0x19U: case 0x1aU: case 0x1bU:
		duk__cbor_decode_push_aival_int(dec_ctx, ib, 0 /*negative*/);
		break;
	case 0x1cU: case 0x1dU: case 0x1eU: case 0x1fU:
		goto format_error;
	case 0x20U: case 0x21U: case 0x22U: case 0x23U: case 0x24U: case 0x25U: case 0x26U: case 0x27U:
	case 0x28U: case 0x29U: case 0x2aU: case 0x2bU: case 0x2cU: case 0x2dU: case 0x2eU: case 0x2fU:
	case 0x30U: case 0x31U: case 0x32U: case 0x33U: case 0x34U: case 0x35U: case 0x36U: case 0x37U:
		duk_push_int(dec_ctx->thr, -((duk_int_t) ((ib - 0x20U) + 1U)));
		break;
	case 0x38U: case 0x39U: case 0x3aU: case 0x3bU:
		duk__cbor_decode_push_aival_int(dec_ctx, ib, 1 /*negative*/);
		break;
	case 0x3cU: case 0x3dU: case 0x3eU: case 0x3fU:
		goto format_error;
	case 0x40U: case 0x41U: case 0x42U: case 0x43U: case 0x44U: case 0x45U: case 0x46U: case 0x47U:
	case 0x48U: case 0x49U: case 0x4aU: case 0x4bU: case 0x4cU: case 0x4dU: case 0x4eU: case 0x4fU:
	case 0x50U: case 0x51U: case 0x52U: case 0x53U: case 0x54U: case 0x55U: case 0x56U: case 0x57U:
		/* XXX: Avoid rewind, we know the length already. */
		DUK_ASSERT(dec_ctx->off > 0U);
		dec_ctx->off--;
		duk__cbor_decode_buffer(dec_ctx, 0x40U);
		break;
	case 0x58U: case 0x59U: case 0x5aU: case 0x5bU:
		/* XXX: Avoid rewind, decode length inline. */
		DUK_ASSERT(dec_ctx->off > 0U);
		dec_ctx->off--;
		duk__cbor_decode_buffer(dec_ctx, 0x40U);
		break;
	case 0x5cU: case 0x5dU: case 0x5eU:
		goto format_error;
	case 0x5fU:
		duk__cbor_decode_and_join_strbuf(dec_ctx, 0x40U);
		break;
	case 0x60U: case 0x61U: case 0x62U: case 0x63U: case 0x64U: case 0x65U: case 0x66U: case 0x67U:
	case 0x68U: case 0x69U: case 0x6aU: case 0x6bU: case 0x6cU: case 0x6dU: case 0x6eU: case 0x6fU:
	case 0x70U: case 0x71U: case 0x72U: case 0x73U: case 0x74U: case 0x75U: case 0x76U: case 0x77U:
		/* XXX: Avoid double decode of length. */
		duk__cbor_decode_string(dec_ctx, ib, DUK__CBOR_AI);
		break;
	case 0x78U: case 0x79U: case 0x7aU: case 0x7bU:
		/* XXX: Avoid double decode of length. */
		duk__cbor_decode_string(dec_ctx, ib, DUK__CBOR_AI);
		break;
	case 0x7cU: case 0x7dU: case 0x7eU:
		goto format_error;
	case 0x7fU:
		duk__cbor_decode_string(dec_ctx, ib, DUK__CBOR_AI);
		break;
	case 0x80U: case 0x81U: case 0x82U: case 0x83U: case 0x84U: case 0x85U: case 0x86U: case 0x87U:
	case 0x88U: case 0x89U: case 0x8aU: case 0x8bU: case 0x8cU: case 0x8dU: case 0x8eU: case 0x8fU:
	case 0x90U: case 0x91U: case 0x92U: case 0x93U: case 0x94U: case 0x95U: case 0x96U: case 0x97U:
		if (DUK_UNLIKELY(duk__cbor_decode_array(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0x98U: case 0x99U: case 0x9aU: case 0x9bU:
		if (DUK_UNLIKELY(duk__cbor_decode_array(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0x9cU: case 0x9dU: case 0x9eU:
		goto format_error;
	case 0x9fU:
		if (DUK_UNLIKELY(duk__cbor_decode_array(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0xa0U: case 0xa1U: case 0xa2U: case 0xa3U: case 0xa4U: case 0xa5U: case 0xa6U: case 0xa7U:
	case 0xa8U: case 0xa9U: case 0xaaU: case 0xabU: case 0xacU: case 0xadU: case 0xaeU: case 0xafU:
	case 0xb0U: case 0xb1U: case 0xb2U: case 0xb3U: case 0xb4U: case 0xb5U: case 0xb6U: case 0xb7U:
		if (DUK_UNLIKELY(duk__cbor_decode_map(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0xb8U: case 0xb9U: case 0xbaU: case 0xbbU:
		if (DUK_UNLIKELY(duk__cbor_decode_map(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0xbcU: case 0xbdU: case 0xbeU:
		goto format_error;
	case 0xbfU:
		if (DUK_UNLIKELY(duk__cbor_decode_map(dec_ctx, ib, DUK__CBOR_AI) == 0)) {
			goto format_error;
		}
		break;
	case 0xc0U: case 0xc1U: case 0xc2U: case 0xc3U: case 0xc4U: case 0xc5U: case 0xc6U: case 0xc7U:
	case 0xc8U: case 0xc9U: case 0xcaU: case 0xcbU: case 0xccU: case 0xcdU: case 0xceU: case 0xcfU:
	case 0xd0U: case 0xd1U: case 0xd2U: case 0xd3U: case 0xd4U: case 0xd5U: case 0xd6U: case 0xd7U:
		/* Tag 0-23: drop. */
		goto reread_initial_byte;
	case 0xd8U: case 0xd9U: case 0xdaU: case 0xdbU:
		duk__cbor_decode_skip_aival_int(dec_ctx, ib);
		goto reread_initial_byte;
	case 0xdcU: case 0xddU: case 0xdeU: case 0xdfU:
		goto format_error;
	case 0xe0U:
		goto format_error;
	case 0xe1U:
		goto format_error;
	case 0xe2U:
		goto format_error;
	case 0xe3U:
		goto format_error;
	case 0xe4U:
		goto format_error;
	case 0xe5U:
		goto format_error;
	case 0xe6U:
		goto format_error;
	case 0xe7U:
		goto format_error;
	case 0xe8U:
		goto format_error;
	case 0xe9U:
		goto format_error;
	case 0xeaU:
		goto format_error;
	case 0xebU:
		goto format_error;
	case 0xecU:
		goto format_error;
	case 0xedU:
		goto format_error;
	case 0xeeU:
		goto format_error;
	case 0xefU:
		goto format_error;
	case 0xf0U:
		goto format_error;
	case 0xf1U:
		goto format_error;
	case 0xf2U:
		goto format_error;
	case 0xf3U:
		goto format_error;
	case 0xf4U:
		duk_push_false(dec_ctx->thr);
		break;
	case 0xf5U:
		duk_push_true(dec_ctx->thr);
		break;
	case 0xf6U:
		duk_push_null(dec_ctx->thr);
		break;
	case 0xf7U:
		duk_push_undefined(dec_ctx->thr);
		break;
	case 0xf8U:
		/* Simple value 32-255, nothing defined yet, so reject. */
		goto format_error;
	case 0xf9U: {
		duk_double_t d;
		d = duk__cbor_decode_half_float(dec_ctx);
		duk_push_number(dec_ctx->thr, d);
		break;
	}
	case 0xfaU: {
		duk_double_t d;
		d = duk__cbor_decode_float(dec_ctx);
		duk_push_number(dec_ctx->thr, d);
		break;
	}
	case 0xfbU: {
		duk_double_t d;
		d = duk__cbor_decode_double(dec_ctx);
		duk_push_number(dec_ctx->thr, d);
		break;
	}
	case 0xfcU:
	case 0xfdU:
	case 0xfeU:
	case 0xffU:
		goto format_error;
	}  /* end switch */

	return;

 format_error:
	duk__cbor_decode_error(dec_ctx);
}
#else  /* DUK_CBOR_DECODE_FASTPATH */
DUK_LOCAL void duk__cbor_decode_value(duk_cbor_decode_context *dec_ctx) {
	duk_uint8_t ib, mt, ai;

	/* Any paths potentially recursing back to duk__cbor_decode_value()
	 * must perform a Duktape value stack growth check.  Avoid the check
	 * here for simple paths like primitive values.
	 */

 reread_initial_byte:
	DUK_DDD(DUK_DDDPRINT("cbor decode off=%ld len=%ld", (long) dec_ctx->off, (long) dec_ctx->len));

	ib = duk__cbor_decode_readbyte(dec_ctx);
	mt = ib >> 5U;
	ai = ib & 0x1fU;

	/* Additional information in [24,27] = [0x18,0x1b] has relatively
	 * uniform handling for all major types: read 1/2/4/8 additional
	 * bytes.  For major type 7 the 1-byte value is a 'simple type', and
	 * 2/4/8-byte values are floats.  For other major types the 1/2/4/8
	 * byte values are integers.  The lengths are uniform, but the typing
	 * is not.
	 */

	switch (mt) {
	case 0U: {  /* unsigned integer */
		duk__cbor_decode_push_aival_int(dec_ctx, ib, 0 /*negative*/);
		break;
	}
	case 1U: {  /* negative integer */
		duk__cbor_decode_push_aival_int(dec_ctx, ib, 1 /*negative*/);
		break;
	}
	case 2U: {  /* byte string */
		if (ai == 0x1fU) {
			duk__cbor_decode_and_join_strbuf(dec_ctx, 0x40U);
		} else {
			duk__cbor_decode_rewind(dec_ctx, 1U);
			duk__cbor_decode_buffer(dec_ctx, 0x40U);
		}
		break;
	}
	case 3U: {  /* text string */
		duk__cbor_decode_string(dec_ctx, ib, ai);
		break;
	}
	case 4U: {  /* array of data items */
		if (DUK_UNLIKELY(duk__cbor_decode_array(dec_ctx, ib, ai) == 0)) {
			goto format_error;
		}
		break;
	}
	case 5U: {  /* map of pairs of data items */
		if (DUK_UNLIKELY(duk__cbor_decode_map(dec_ctx, ib, ai) == 0)) {
			goto format_error;
		}
		break;
	}
	case 6U: {  /* semantic tagging */
		/* Tags are ignored now, re-read initial byte.  A tagged
		 * value may itself be tagged (an unlimited number of times)
		 * so keep on peeling away tags.
		 */
		duk__cbor_decode_skip_aival_int(dec_ctx, ib);
		goto reread_initial_byte;
	}
	case 7U: {  /* floating point numbers, simple data types, break; other */
		switch (ai) {
		case 0x14U: {
			duk_push_false(dec_ctx->thr);
			break;
		}
		case 0x15U: {
			duk_push_true(dec_ctx->thr);
			break;
		}
		case 0x16U: {
			duk_push_null(dec_ctx->thr);
			break;
		}
		case 0x17U: {
			duk_push_undefined(dec_ctx->thr);
			break;
		}
		case 0x18U: {  /* more simple values (1 byte) */
			/* Simple value encoded in additional byte (none
			 * are defined so far).  RFC 7049 states that the
			 * follow-up byte must be 32-255 to minimize
			 * confusion.  So, a non-shortest encoding like
			 * f815 (= true, shortest encoding f5) must be
			 * rejected.  cbor.me tester rejects f815, but
			 * e.g. Python CBOR binding decodes it as true.
			 */
			goto format_error;
		}
		case 0x19U: {  /* half-float (2 bytes) */
			duk_double_t d;
			d = duk__cbor_decode_half_float(dec_ctx);
			duk_push_number(dec_ctx->thr, d);
			break;
		}
		case 0x1aU: {  /* float (4 bytes) */
			duk_double_t d;
			d = duk__cbor_decode_float(dec_ctx);
			duk_push_number(dec_ctx->thr, d);
			break;
		}
		case 0x1bU: {  /* double (8 bytes) */
			duk_double_t d;
			d = duk__cbor_decode_double(dec_ctx);
			duk_push_number(dec_ctx->thr, d);
			break;
		}
		case 0xffU:  /* unexpected break */
		default: {
			goto format_error;
		}
		}  /* end switch */
		break;
	}
	default: {
		goto format_error;  /* will never actually occur */
	}
	}  /* end switch */

	return;

 format_error:
	duk__cbor_decode_error(dec_ctx);
}
#endif  /* DUK_CBOR_DECODE_FASTPATH */

DUK_LOCAL void duk__cbor_encode(duk_hthread *thr, duk_idx_t idx, duk_uint_t encode_flags) {
	duk_cbor_encode_context enc_ctx;
	duk_uint8_t *buf;

	DUK_UNREF(encode_flags);

	idx = duk_require_normalize_index(thr, idx);

	enc_ctx.thr = thr;
	enc_ctx.idx_buf = duk_get_top(thr);

	enc_ctx.len = 64;
	buf = (duk_uint8_t *) duk_push_dynamic_buffer(thr, enc_ctx.len);
	enc_ctx.ptr = buf;
	enc_ctx.buf = buf;
	enc_ctx.buf_end = buf + enc_ctx.len;

	duk_dup(thr, idx);
	duk__cbor_encode_value(&enc_ctx);
	duk_resize_buffer(enc_ctx.thr, enc_ctx.idx_buf, (duk_size_t) (enc_ctx.ptr - enc_ctx.buf));
	duk_replace(thr, idx);
}

DUK_LOCAL void duk__cbor_decode(duk_hthread *thr, duk_idx_t idx, duk_uint_t decode_flags) {
	duk_cbor_decode_context dec_ctx;

	DUK_UNREF(decode_flags);

	/* Suppress compile warnings for functions only needed with e.g.
	 * asserts enabled.
	 */
	DUK_UNREF(duk__cbor_get_reserve);

	idx = duk_require_normalize_index(thr, idx);

	dec_ctx.thr = thr;
	dec_ctx.buf = (const duk_uint8_t *) duk_require_buffer_data(thr, idx, &dec_ctx.len);
	dec_ctx.off = 0;
	/* dec_ctx.len: set above */

	duk__cbor_req_stack(&dec_ctx);
	duk__cbor_decode_value(&dec_ctx);
	if (dec_ctx.off != dec_ctx.len) {
		(void) duk_type_error(thr, "trailing garbage");
	}

	duk_replace(thr, idx);
}

#else  /* DUK_USE_CBOR_SUPPORT */

DUK_LOCAL void duk__cbor_encode(duk_hthread *thr, duk_idx_t idx, duk_uint_t encode_flags) {
	DUK_UNREF(idx);
	DUK_UNREF(encode_flags);
	DUK_ERROR_UNSUPPORTED(thr);
}

DUK_LOCAL void duk__cbor_decode(duk_hthread *thr, duk_idx_t idx, duk_uint_t decode_flags) {
	DUK_UNREF(idx);
	DUK_UNREF(decode_flags);
	DUK_ERROR_UNSUPPORTED(thr);
}

#endif  /* DUK_USE_CBOR_SUPPORT */

/*
 *  Public APIs
 */

DUK_EXTERNAL void duk_cbor_encode(duk_hthread *thr, duk_idx_t idx, duk_uint_t encode_flags) {
	DUK_ASSERT_API_ENTRY(thr);
	duk__cbor_encode(thr, idx, encode_flags);
}
DUK_EXTERNAL void duk_cbor_decode(duk_hthread *thr, duk_idx_t idx, duk_uint_t decode_flags) {
	DUK_ASSERT_API_ENTRY(thr);
	duk__cbor_decode(thr, idx, decode_flags);
}

#if defined(DUK_USE_CBOR_BUILTIN)
#if defined(DUK_USE_CBOR_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_cbor_encode(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 1);

	duk__cbor_encode(thr, -1, 0 /*flags*/);

	/* Produce an ArrayBuffer by first decoding into a plain buffer which
	 * mimics a Uint8Array and gettings its .buffer property.
	 */
	/* XXX: shortcut */
	(void) duk_get_prop_stridx(thr, -1, DUK_STRIDX_LC_BUFFER);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_cbor_decode(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 1);

	duk__cbor_decode(thr, -1, 0 /*flags*/);
	return 1;
}
#else  /* DUK_USE_CBOR_SUPPORT */
DUK_INTERNAL duk_ret_t duk_bi_cbor_encode(duk_hthread *thr) {
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return 0;);
}
DUK_INTERNAL duk_ret_t duk_bi_cbor_decode(duk_hthread *thr) {
	DUK_ERROR_UNSUPPORTED(thr);
	DUK_WO_NORETURN(return 0;);
}
#endif  /* DUK_USE_CBOR_SUPPORT */
#endif  /* DUK_USE_CBOR_BUILTIN */

/* automatic undefs */
#undef DUK__CBOR_AI
/*
 *  Date built-ins
 *
 *  Unlike most built-ins, Date has some platform dependencies for getting
 *  UTC time, converting between UTC and local time, and parsing and
 *  formatting time values.  These are all abstracted behind DUK_USE_xxx
 *  config options.  There are built-in platform specific providers for
 *  POSIX and Windows, but external providers can also be used.
 *
 *  See doc/datetime.rst.
 *
 */

/* #include duk_internal.h -> already included */

/* XXX: currently defines unnecessary symbols when DUK_USE_DATE_BUILTIN is disabled. */

/*
 *  Forward declarations
 */

DUK_LOCAL_DECL duk_double_t duk__push_this_get_timeval_tzoffset(duk_hthread *thr, duk_small_uint_t flags, duk_int_t *out_tzoffset);
DUK_LOCAL_DECL duk_double_t duk__push_this_get_timeval(duk_hthread *thr, duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__twodigit_year_fixup(duk_hthread *thr, duk_idx_t idx_val);
DUK_LOCAL_DECL duk_ret_t duk__set_this_timeval_from_dparts(duk_hthread *thr, duk_double_t *dparts, duk_small_uint_t flags);

/*
 *  Other file level defines
 */

/* Debug macro to print all parts and dparts (used manually because of debug level). */
#define  DUK__DPRINT_PARTS_AND_DPARTS(parts,dparts)  do { \
		DUK_D(DUK_DPRINT("parts: %ld %ld %ld %ld %ld %ld %ld %ld, dparts: %lf %lf %lf %lf %lf %lf %lf %lf", \
		                 (long) (parts)[0], (long) (parts)[1], \
		                 (long) (parts)[2], (long) (parts)[3], \
		                 (long) (parts)[4], (long) (parts)[5], \
		                 (long) (parts)[6], (long) (parts)[7], \
		                 (double) (dparts)[0], (double) (dparts)[1], \
		                 (double) (dparts)[2], (double) (dparts)[3], \
		                 (double) (dparts)[4], (double) (dparts)[5], \
		                 (double) (dparts)[6], (double) (dparts)[7])); \
	} while (0)
#define  DUK__DPRINT_PARTS(parts)  do { \
		DUK_D(DUK_DPRINT("parts: %ld %ld %ld %ld %ld %ld %ld %ld", \
		                 (long) (parts)[0], (long) (parts)[1], \
		                 (long) (parts)[2], (long) (parts)[3], \
		                 (long) (parts)[4], (long) (parts)[5], \
		                 (long) (parts)[6], (long) (parts)[7])); \
	} while (0)
#define  DUK__DPRINT_DPARTS(dparts)  do { \
		DUK_D(DUK_DPRINT("dparts: %lf %lf %lf %lf %lf %lf %lf %lf", \
		                 (double) (dparts)[0], (double) (dparts)[1], \
		                 (double) (dparts)[2], (double) (dparts)[3], \
		                 (double) (dparts)[4], (double) (dparts)[5], \
		                 (double) (dparts)[6], (double) (dparts)[7])); \
	} while (0)

/* Equivalent year for DST calculations outside [1970,2038[ range, see
 * E5 Section 15.9.1.8.  Equivalent year has the same leap-year-ness and
 * starts with the same weekday on Jan 1.
 * https://bugzilla.mozilla.org/show_bug.cgi?id=351066
 */
#define DUK__YEAR(x) ((duk_uint8_t) ((x) - 1970))
DUK_LOCAL duk_uint8_t duk__date_equivyear[14] = {
#if 1
	/* This is based on V8 EquivalentYear() algorithm (see util/genequivyear.py):
	 * http://code.google.com/p/v8/source/browse/trunk/src/date.h#146
	 */

	/* non-leap year: sunday, monday, ... */
	DUK__YEAR(2023), DUK__YEAR(2035), DUK__YEAR(2019), DUK__YEAR(2031),
	DUK__YEAR(2015), DUK__YEAR(2027), DUK__YEAR(2011),

	/* leap year: sunday, monday, ... */
	DUK__YEAR(2012), DUK__YEAR(2024), DUK__YEAR(2008), DUK__YEAR(2020),
	DUK__YEAR(2032), DUK__YEAR(2016), DUK__YEAR(2028)
#endif

#if 0
	/* This is based on Rhino EquivalentYear() algorithm:
	 * https://github.com/mozilla/rhino/blob/f99cc11d616f0cdda2c42bde72b3484df6182947/src/org/mozilla/javascript/NativeDate.java
	 */

	/* non-leap year: sunday, monday, ... */
	DUK__YEAR(1978), DUK__YEAR(1973), DUK__YEAR(1985), DUK__YEAR(1986),
	DUK__YEAR(1981), DUK__YEAR(1971), DUK__YEAR(1977),

	/* leap year: sunday, monday, ... */
	DUK__YEAR(1984), DUK__YEAR(1996), DUK__YEAR(1980), DUK__YEAR(1992),
	DUK__YEAR(1976), DUK__YEAR(1988), DUK__YEAR(1972)
#endif
};

/*
 *  ISO 8601 subset parser.
 */

/* Parser part count. */
#define DUK__NUM_ISO8601_PARSER_PARTS  9

/* Parser part indices. */
#define DUK__PI_YEAR         0
#define DUK__PI_MONTH        1
#define DUK__PI_DAY          2
#define DUK__PI_HOUR         3
#define DUK__PI_MINUTE       4
#define DUK__PI_SECOND       5
#define DUK__PI_MILLISECOND  6
#define DUK__PI_TZHOUR       7
#define DUK__PI_TZMINUTE     8

/* Parser part masks. */
#define DUK__PM_YEAR         (1 << DUK__PI_YEAR)
#define DUK__PM_MONTH        (1 << DUK__PI_MONTH)
#define DUK__PM_DAY          (1 << DUK__PI_DAY)
#define DUK__PM_HOUR         (1 << DUK__PI_HOUR)
#define DUK__PM_MINUTE       (1 << DUK__PI_MINUTE)
#define DUK__PM_SECOND       (1 << DUK__PI_SECOND)
#define DUK__PM_MILLISECOND  (1 << DUK__PI_MILLISECOND)
#define DUK__PM_TZHOUR       (1 << DUK__PI_TZHOUR)
#define DUK__PM_TZMINUTE     (1 << DUK__PI_TZMINUTE)

/* Parser separator indices. */
#define DUK__SI_PLUS         0
#define DUK__SI_MINUS        1
#define DUK__SI_T            2
#define DUK__SI_SPACE        3
#define DUK__SI_COLON        4
#define DUK__SI_PERIOD       5
#define DUK__SI_Z            6
#define DUK__SI_NUL          7

/* Parser separator masks. */
#define DUK__SM_PLUS         (1 << DUK__SI_PLUS)
#define DUK__SM_MINUS        (1 << DUK__SI_MINUS)
#define DUK__SM_T            (1 << DUK__SI_T)
#define DUK__SM_SPACE        (1 << DUK__SI_SPACE)
#define DUK__SM_COLON        (1 << DUK__SI_COLON)
#define DUK__SM_PERIOD       (1 << DUK__SI_PERIOD)
#define DUK__SM_Z            (1 << DUK__SI_Z)
#define DUK__SM_NUL          (1 << DUK__SI_NUL)

/* Rule control flags. */
#define DUK__CF_NEG          (1 << 0)  /* continue matching, set neg_tzoffset flag */
#define DUK__CF_ACCEPT       (1 << 1)  /* accept string */
#define DUK__CF_ACCEPT_NUL   (1 << 2)  /* accept string if next char is NUL (otherwise reject) */

#define DUK__PACK_RULE(partmask,sepmask,nextpart,flags)  \
	((duk_uint32_t) (partmask) + \
	 (((duk_uint32_t) (sepmask)) << 9) + \
	 (((duk_uint32_t) (nextpart)) << 17) + \
	 (((duk_uint32_t) (flags)) << 21))

#define DUK__UNPACK_RULE(rule,var_nextidx,var_flags)  do { \
		(var_nextidx) = (duk_small_uint_t) (((rule) >> 17) & 0x0f); \
		(var_flags) = (duk_small_uint_t) ((rule) >> 21); \
	} while (0)

#define DUK__RULE_MASK_PART_SEP  0x1ffffUL

/* Matching separator index is used in the control table */
DUK_LOCAL const duk_uint8_t duk__parse_iso8601_seps[] = {
	DUK_ASC_PLUS /*0*/, DUK_ASC_MINUS /*1*/, DUK_ASC_UC_T /*2*/, DUK_ASC_SPACE /*3*/,
	DUK_ASC_COLON /*4*/, DUK_ASC_PERIOD /*5*/, DUK_ASC_UC_Z /*6*/, DUK_ASC_NUL /*7*/
};

/* Rule table: first matching rule is used to determine what to do next. */
DUK_LOCAL const duk_uint32_t duk__parse_iso8601_control[] = {
	DUK__PACK_RULE(DUK__PM_YEAR, DUK__SM_MINUS, DUK__PI_MONTH, 0),
	DUK__PACK_RULE(DUK__PM_MONTH, DUK__SM_MINUS, DUK__PI_DAY, 0),
	DUK__PACK_RULE(DUK__PM_YEAR | DUK__PM_MONTH | DUK__PM_DAY, DUK__SM_T | DUK__SM_SPACE, DUK__PI_HOUR, 0),
	DUK__PACK_RULE(DUK__PM_HOUR, DUK__SM_COLON, DUK__PI_MINUTE, 0),
	DUK__PACK_RULE(DUK__PM_MINUTE, DUK__SM_COLON, DUK__PI_SECOND, 0),
	DUK__PACK_RULE(DUK__PM_SECOND, DUK__SM_PERIOD, DUK__PI_MILLISECOND, 0),
	DUK__PACK_RULE(DUK__PM_TZHOUR, DUK__SM_COLON, DUK__PI_TZMINUTE, 0),
	DUK__PACK_RULE(DUK__PM_YEAR | DUK__PM_MONTH | DUK__PM_DAY | DUK__PM_HOUR /*Note1*/ | DUK__PM_MINUTE | DUK__PM_SECOND | DUK__PM_MILLISECOND, DUK__SM_PLUS, DUK__PI_TZHOUR, 0),
	DUK__PACK_RULE(DUK__PM_YEAR | DUK__PM_MONTH | DUK__PM_DAY | DUK__PM_HOUR /*Note1*/ | DUK__PM_MINUTE | DUK__PM_SECOND | DUK__PM_MILLISECOND, DUK__SM_MINUS, DUK__PI_TZHOUR, DUK__CF_NEG),
	DUK__PACK_RULE(DUK__PM_YEAR | DUK__PM_MONTH | DUK__PM_DAY | DUK__PM_HOUR /*Note1*/ | DUK__PM_MINUTE | DUK__PM_SECOND | DUK__PM_MILLISECOND, DUK__SM_Z, 0, DUK__CF_ACCEPT_NUL),
	DUK__PACK_RULE(DUK__PM_YEAR | DUK__PM_MONTH | DUK__PM_DAY | DUK__PM_HOUR /*Note1*/ | DUK__PM_MINUTE | DUK__PM_SECOND | DUK__PM_MILLISECOND | DUK__PM_TZHOUR /*Note2*/ | DUK__PM_TZMINUTE, DUK__SM_NUL, 0, DUK__CF_ACCEPT)

	/* Note1: the specification doesn't require matching a time form with
	 *        just hours ("HH"), but we accept it here, e.g. "2012-01-02T12Z".
	 *
	 * Note2: the specification doesn't require matching a timezone offset
	 *        with just hours ("HH"), but accept it here, e.g. "2012-01-02T03:04:05+02"
	 */
};

DUK_LOCAL duk_bool_t duk__parse_string_iso8601_subset(duk_hthread *thr, const char *str) {
	duk_int_t parts[DUK__NUM_ISO8601_PARSER_PARTS];
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t d;
	const duk_uint8_t *p;
	duk_small_uint_t part_idx = 0;
	duk_int_t accum = 0;
	duk_small_uint_t ndigits = 0;
	duk_bool_t neg_year = 0;
	duk_bool_t neg_tzoffset = 0;
	duk_uint_fast8_t ch;
	duk_small_uint_t i;

	/* During parsing, month and day are one-based; set defaults here. */
	duk_memzero(parts, sizeof(parts));
	DUK_ASSERT(parts[DUK_DATE_IDX_YEAR] == 0);  /* don't care value, year is mandatory */
	parts[DUK_DATE_IDX_MONTH] = 1;
	parts[DUK_DATE_IDX_DAY] = 1;

	/* Special handling for year sign. */
	p = (const duk_uint8_t *) str;
	ch = p[0];
	if (ch == DUK_ASC_PLUS) {
		p++;
	} else if (ch == DUK_ASC_MINUS) {
		neg_year = 1;
		p++;
	}

	for (;;) {
		ch = *p++;
		DUK_DDD(DUK_DDDPRINT("parsing, part_idx=%ld, char=%ld ('%c')",
		                     (long) part_idx, (long) ch,
		                     (int) ((ch >= 0x20 && ch <= 0x7e) ? ch : DUK_ASC_QUESTION)));

		if (ch >= DUK_ASC_0 && ch <= DUK_ASC_9) {
			if (ndigits >= 9) {
				DUK_DDD(DUK_DDDPRINT("too many digits -> reject"));
				goto reject;
			}
			if (part_idx == DUK__PI_MILLISECOND && ndigits >= 3) {
				/* ignore millisecond fractions after 3 */
			} else {
				accum = accum * 10 + ((duk_int_t) ch) - ((duk_int_t) DUK_ASC_0) + 0x00;
				ndigits++;
			}
		} else {
			duk_uint_fast32_t match_val;
			duk_small_uint_t sep_idx;

			if (ndigits <= 0) {
				goto reject;
			}
			if (part_idx == DUK__PI_MILLISECOND) {
				/* complete the millisecond field */
				while (ndigits < 3) {
					accum *= 10;
					ndigits++;
				}
			}
			parts[part_idx] = accum;
			DUK_DDD(DUK_DDDPRINT("wrote part %ld -> value %ld", (long) part_idx, (long) accum));

			accum = 0;
			ndigits = 0;

			for (i = 0; i < (duk_small_uint_t) (sizeof(duk__parse_iso8601_seps) / sizeof(duk_uint8_t)); i++) {
				if (duk__parse_iso8601_seps[i] == ch) {
					break;
				}
			}
			if (i == (duk_small_uint_t) (sizeof(duk__parse_iso8601_seps) / sizeof(duk_uint8_t))) {
				DUK_DDD(DUK_DDDPRINT("separator character doesn't match -> reject"));
				goto reject;
			}

			sep_idx = i;
			match_val = (1UL << part_idx) + (1UL << (sep_idx + 9));  /* match against rule part/sep bits */

			for (i = 0; i < (duk_small_uint_t) (sizeof(duk__parse_iso8601_control) / sizeof(duk_uint32_t)); i++) {
				duk_uint_fast32_t rule = duk__parse_iso8601_control[i];
				duk_small_uint_t nextpart;
				duk_small_uint_t cflags;

				DUK_DDD(DUK_DDDPRINT("part_idx=%ld, sep_idx=%ld, match_val=0x%08lx, considering rule=0x%08lx",
				                     (long) part_idx, (long) sep_idx,
				                     (unsigned long) match_val, (unsigned long) rule));

				if ((rule & match_val) != match_val) {
					continue;
				}

				DUK__UNPACK_RULE(rule, nextpart, cflags);

				DUK_DDD(DUK_DDDPRINT("rule match -> part_idx=%ld, sep_idx=%ld, match_val=0x%08lx, "
				                     "rule=0x%08lx -> nextpart=%ld, cflags=0x%02lx",
				                     (long) part_idx, (long) sep_idx,
				                     (unsigned long) match_val, (unsigned long) rule,
				                     (long) nextpart, (unsigned long) cflags));

				if (cflags & DUK__CF_NEG) {
					neg_tzoffset = 1;
				}

				if (cflags & DUK__CF_ACCEPT) {
					goto accept;
				}

				if (cflags & DUK__CF_ACCEPT_NUL) {
					DUK_ASSERT(*(p - 1) != (char) 0);
					if (*p == DUK_ASC_NUL) {
						goto accept;
					}
					goto reject;
				}

				part_idx = nextpart;
				break;
			}  /* rule match */

			if (i == (duk_small_uint_t) (sizeof(duk__parse_iso8601_control) / sizeof(duk_uint32_t))) {
				DUK_DDD(DUK_DDDPRINT("no rule matches -> reject"));
				goto reject;
			}

			if (ch == 0) {
				/* This shouldn't be necessary, but check just in case
				 * to avoid any chance of overruns.
				 */
				DUK_DDD(DUK_DDDPRINT("NUL after rule matching (should not happen) -> reject"));
				goto reject;
			}
		}  /* if-digit-else-ctrl */
	}  /* char loop */

	/* We should never exit the loop above. */
	DUK_UNREACHABLE();

 reject:
	DUK_DDD(DUK_DDDPRINT("reject"));
	return 0;

 accept:
	DUK_DDD(DUK_DDDPRINT("accept"));

	/* Apply timezone offset to get the main parts in UTC */
	if (neg_year) {
		parts[DUK__PI_YEAR] = -parts[DUK__PI_YEAR];
	}
	if (neg_tzoffset) {
		parts[DUK__PI_HOUR] += parts[DUK__PI_TZHOUR];
		parts[DUK__PI_MINUTE] += parts[DUK__PI_TZMINUTE];
	} else {
		parts[DUK__PI_HOUR] -= parts[DUK__PI_TZHOUR];
		parts[DUK__PI_MINUTE] -= parts[DUK__PI_TZMINUTE];
	}
	parts[DUK__PI_MONTH] -= 1;  /* zero-based month */
	parts[DUK__PI_DAY] -= 1;  /* zero-based day */

	/* Use double parts, they tolerate unnormalized time.
	 *
	 * Note: DUK_DATE_IDX_WEEKDAY is initialized with a bogus value (DUK__PI_TZHOUR)
	 * on purpose.  It won't be actually used by duk_bi_date_get_timeval_from_dparts(),
	 * but will make the value initialized just in case, and avoid any
	 * potential for Valgrind issues.
	 */
	for (i = 0; i < DUK_DATE_IDX_NUM_PARTS; i++) {
		DUK_DDD(DUK_DDDPRINT("part[%ld] = %ld", (long) i, (long) parts[i]));
		dparts[i] = parts[i];
	}

	d = duk_bi_date_get_timeval_from_dparts(dparts, 0 /*flags*/);
	duk_push_number(thr, d);
	return 1;
}

/*
 *  Date/time parsing helper.
 *
 *  Parse a datetime string into a time value.  We must first try to parse
 *  the input according to the standard format in E5.1 Section 15.9.1.15.
 *  If that fails, we can try to parse using custom parsing, which can
 *  either be platform neutral (custom code) or platform specific (using
 *  existing platform API calls).
 *
 *  Note in particular that we must parse whatever toString(), toUTCString(),
 *  and toISOString() can produce; see E5.1 Section 15.9.4.2.
 *
 *  Returns 1 to allow tail calling.
 *
 *  There is much room for improvement here with respect to supporting
 *  alternative datetime formats.  For instance, V8 parses '2012-01-01' as
 *  UTC and '2012/01/01' as local time.
 */

DUK_LOCAL duk_ret_t duk__parse_string(duk_hthread *thr, const char *str) {
	/* XXX: there is a small risk here: because the ISO 8601 parser is
	 * very loose, it may end up parsing some datetime values which
	 * would be better parsed with a platform specific parser.
	 */

	DUK_ASSERT(str != NULL);
	DUK_DDD(DUK_DDDPRINT("parse datetime from string '%s'", (const char *) str));

	if (duk__parse_string_iso8601_subset(thr, str) != 0) {
		return 1;
	}

#if defined(DUK_USE_DATE_PARSE_STRING)
	/* Contract, either:
	 * - Push value on stack and return 1
	 * - Don't push anything on stack and return 0
	 */

	if (DUK_USE_DATE_PARSE_STRING(thr, str) != 0) {
		return 1;
	}
#else
	/* No platform-specific parsing, this is not an error. */
#endif

	duk_push_nan(thr);
	return 1;
}

/*
 *  Calendar helpers
 *
 *  Some helpers are used for getters and can operate on normalized values
 *  which can be represented with 32-bit signed integers.  Other helpers are
 *  needed by setters and operate on un-normalized double values, must watch
 *  out for non-finite numbers etc.
 */

DUK_LOCAL duk_uint8_t duk__days_in_month[12] = {
	(duk_uint8_t) 31, (duk_uint8_t) 28, (duk_uint8_t) 31, (duk_uint8_t) 30,
	(duk_uint8_t) 31, (duk_uint8_t) 30, (duk_uint8_t) 31, (duk_uint8_t) 31,
	(duk_uint8_t) 30, (duk_uint8_t) 31, (duk_uint8_t) 30, (duk_uint8_t) 31
};

/* Maximum iteration count for computing UTC-to-local time offset when
 * creating an ECMAScript time value from local parts.
 */
#define DUK__LOCAL_TZOFFSET_MAXITER   4

/* Because 'day since epoch' can be negative and is used to compute weekday
 * using a modulo operation, add this multiple of 7 to avoid negative values
 * when year is below 1970 epoch.  ECMAScript time values are restricted to
 * +/- 100 million days from epoch, so this adder fits nicely into 32 bits.
 * Round to a multiple of 7 (= floor(100000000 / 7) * 7) and add margin.
 */
#define DUK__WEEKDAY_MOD_ADDER  (20000000 * 7)  /* 0x08583b00 */

DUK_INTERNAL duk_bool_t duk_bi_date_is_leap_year(duk_int_t year) {
	if ((year % 4) != 0) {
		return 0;
	}
	if ((year % 100) != 0) {
		return 1;
	}
	if ((year % 400) != 0) {
		return 0;
	}
	return 1;
}

DUK_INTERNAL duk_bool_t duk_bi_date_timeval_in_valid_range(duk_double_t x) {
	return (x >= -DUK_DATE_MSEC_100M_DAYS && x <= DUK_DATE_MSEC_100M_DAYS);
}

DUK_INTERNAL duk_bool_t duk_bi_date_timeval_in_leeway_range(duk_double_t x) {
	return (x >= -DUK_DATE_MSEC_100M_DAYS_LEEWAY && x <= DUK_DATE_MSEC_100M_DAYS_LEEWAY);
}

DUK_INTERNAL duk_bool_t duk_bi_date_year_in_valid_range(duk_double_t x) {
	return (x >= DUK_DATE_MIN_ECMA_YEAR && x <= DUK_DATE_MAX_ECMA_YEAR);
}

DUK_LOCAL duk_double_t duk__timeclip(duk_double_t x) {
	if (!DUK_ISFINITE(x)) {
		return DUK_DOUBLE_NAN;
	}

	if (!duk_bi_date_timeval_in_valid_range(x)) {
		return DUK_DOUBLE_NAN;
	}

	x = duk_js_tointeger_number(x);

	/* Here we'd have the option to normalize -0 to +0. */
	return x;
}

/* Integer division which floors also negative values correctly. */
DUK_LOCAL duk_int_t duk__div_floor(duk_int_t a, duk_int_t b) {
	DUK_ASSERT(b > 0);
	if (a >= 0) {
		return a / b;
	} else {
		/* e.g. a = -4, b = 5  -->  -4 - 5 + 1 / 5  -->  -8 / 5  -->  -1
		 *      a = -5, b = 5  -->  -5 - 5 + 1 / 5  -->  -9 / 5  -->  -1
		 *      a = -6, b = 5  -->  -6 - 5 + 1 / 5  -->  -10 / 5  -->  -2
		 */
		return (a - b + 1) / b;
	}
}

/* Compute day number of the first day of a given year. */
DUK_LOCAL duk_int_t duk__day_from_year(duk_int_t year) {
	/* Note: in integer arithmetic, (x / 4) is same as floor(x / 4) for non-negative
	 * values, but is incorrect for negative ones.
	 */
	return 365 * (year - 1970)
	       + duk__div_floor(year - 1969, 4)
	       - duk__div_floor(year - 1901, 100)
	       + duk__div_floor(year - 1601, 400);
}

/* Given a day number, determine year and day-within-year. */
DUK_LOCAL duk_int_t duk__year_from_day(duk_int_t day, duk_small_int_t *out_day_within_year) {
	duk_int_t year;
	duk_int_t diff_days;

	/* estimate year upwards (towards positive infinity), then back down;
	 * two iterations should be enough
	 */

	if (day >= 0) {
		year = 1970 + day / 365;
	} else {
		year = 1970 + day / 366;
	}

	for (;;) {
		diff_days = duk__day_from_year(year) - day;
		DUK_DDD(DUK_DDDPRINT("year=%ld day=%ld, diff_days=%ld", (long) year, (long) day, (long) diff_days));
		if (diff_days <= 0) {
			DUK_ASSERT(-diff_days < 366);  /* fits into duk_small_int_t */
			*out_day_within_year = -diff_days;
			DUK_DDD(DUK_DDDPRINT("--> year=%ld, day-within-year=%ld",
			                     (long) year, (long) *out_day_within_year));
			DUK_ASSERT(*out_day_within_year >= 0);
			DUK_ASSERT(*out_day_within_year < (duk_bi_date_is_leap_year(year) ? 366 : 365));
			return year;
		}

		/* Note: this is very tricky; we must never 'overshoot' the
		 * correction downwards.
		 */
		year -= 1 + (diff_days - 1) / 366;  /* conservative */
	}
}

/* Given a (year, month, day-within-month) triple, compute day number.
 * The input triple is un-normalized and may contain non-finite values.
 */
DUK_LOCAL duk_double_t duk__make_day(duk_double_t year, duk_double_t month, duk_double_t day) {
	duk_int_t day_num;
	duk_bool_t is_leap;
	duk_small_int_t i, n;

	/* Assume that year, month, day are all coerced to whole numbers.
	 * They may also be NaN or infinity, in which case this function
	 * must return NaN or infinity to ensure time value becomes NaN.
	 * If 'day' is NaN, the final return will end up returning a NaN,
	 * so it doesn't need to be checked here.
	 */

	if (!DUK_ISFINITE(year) || !DUK_ISFINITE(month)) {
		return DUK_DOUBLE_NAN;
	}

	year += DUK_FLOOR(month / 12.0);

	month = DUK_FMOD(month, 12.0);
	if (month < 0.0) {
		/* handle negative values */
		month += 12.0;
	}

	/* The algorithm in E5.1 Section 15.9.1.12 normalizes month, but
	 * does not normalize the day-of-month (nor check whether or not
	 * it is finite) because it's not necessary for finding the day
	 * number which matches the (year,month) pair.
	 *
	 * We assume that duk__day_from_year() is exact here.
	 *
	 * Without an explicit infinity / NaN check in the beginning,
	 * day_num would be a bogus integer here.
	 *
	 * It's possible for 'year' to be out of integer range here.
	 * If so, we need to return NaN without integer overflow.
	 * This fixes test-bug-setyear-overflow.js.
	 */

	if (!duk_bi_date_year_in_valid_range(year)) {
		DUK_DD(DUK_DDPRINT("year not in ecmascript valid range, avoid integer overflow: %lf", (double) year));
		return DUK_DOUBLE_NAN;
	}
	day_num = duk__day_from_year((duk_int_t) year);
	is_leap = duk_bi_date_is_leap_year((duk_int_t) year);

	n = (duk_small_int_t) month;
	for (i = 0; i < n; i++) {
		day_num += duk__days_in_month[i];
		if (i == 1 && is_leap) {
			day_num++;
		}
	}

	/* If 'day' is NaN, returns NaN. */
	return (duk_double_t) day_num + day;
}

/* Split time value into parts.  The time value may contain fractions (it may
 * come from duk_time_to_components() API call) which are truncated.  Possible
 * local time adjustment has already been applied when reading the time value.
 */
DUK_INTERNAL void duk_bi_date_timeval_to_parts(duk_double_t d, duk_int_t *parts, duk_double_t *dparts, duk_small_uint_t flags) {
	duk_double_t d1, d2;
	duk_int_t t1, t2;
	duk_int_t day_since_epoch;
	duk_int_t year;  /* does not fit into 16 bits */
	duk_small_int_t day_in_year;
	duk_small_int_t month;
	duk_small_int_t day;
	duk_small_int_t dim;
	duk_int_t jan1_since_epoch;
	duk_small_int_t jan1_weekday;
	duk_int_t equiv_year;
	duk_small_uint_t i;
	duk_bool_t is_leap;
	duk_small_int_t arridx;

	DUK_ASSERT(DUK_ISFINITE(d));    /* caller checks */
	d = DUK_FLOOR(d);  /* remove fractions if present */
	DUK_ASSERT(duk_double_equals(DUK_FLOOR(d), d));

	/* The timevalue must be in valid ECMAScript range, but since a local
	 * time offset can be applied, we need to allow a +/- 24h leeway to
	 * the value.  In other words, although the UTC time is within the
	 * ECMAScript range, the local part values can be just outside of it.
	 */
	DUK_UNREF(duk_bi_date_timeval_in_leeway_range);
	DUK_ASSERT(duk_bi_date_timeval_in_leeway_range(d));

	/* These computations are guaranteed to be exact for the valid
	 * E5 time value range, assuming milliseconds without fractions.
	 */
	d1 = (duk_double_t) DUK_FMOD(d, (double) DUK_DATE_MSEC_DAY);
	if (d1 < 0.0) {
		/* deal with negative values */
		d1 += (duk_double_t) DUK_DATE_MSEC_DAY;
	}
	d2 = DUK_FLOOR((double) (d / (duk_double_t) DUK_DATE_MSEC_DAY));
	DUK_ASSERT(duk_double_equals(d2 * ((duk_double_t) DUK_DATE_MSEC_DAY) + d1, d));
	/* now expected to fit into a 32-bit integer */
	t1 = (duk_int_t) d1;
	t2 = (duk_int_t) d2;
	day_since_epoch = t2;
	DUK_ASSERT(duk_double_equals((duk_double_t) t1, d1));
	DUK_ASSERT(duk_double_equals((duk_double_t) t2, d2));

	/* t1 = milliseconds within day (fits 32 bit)
	 * t2 = day number from epoch (fits 32 bit, may be negative)
	 */

	parts[DUK_DATE_IDX_MILLISECOND] = t1 % 1000; t1 /= 1000;
	parts[DUK_DATE_IDX_SECOND] = t1 % 60; t1 /= 60;
	parts[DUK_DATE_IDX_MINUTE] = t1 % 60; t1 /= 60;
	parts[DUK_DATE_IDX_HOUR] = t1;
	DUK_ASSERT(parts[DUK_DATE_IDX_MILLISECOND] >= 0 && parts[DUK_DATE_IDX_MILLISECOND] <= 999);
	DUK_ASSERT(parts[DUK_DATE_IDX_SECOND] >= 0 && parts[DUK_DATE_IDX_SECOND] <= 59);
	DUK_ASSERT(parts[DUK_DATE_IDX_MINUTE] >= 0 && parts[DUK_DATE_IDX_MINUTE] <= 59);
	DUK_ASSERT(parts[DUK_DATE_IDX_HOUR] >= 0 && parts[DUK_DATE_IDX_HOUR] <= 23);

	DUK_DDD(DUK_DDDPRINT("d=%lf, d1=%lf, d2=%lf, t1=%ld, t2=%ld, parts: hour=%ld min=%ld sec=%ld msec=%ld",
	                     (double) d, (double) d1, (double) d2, (long) t1, (long) t2,
	                     (long) parts[DUK_DATE_IDX_HOUR],
	                     (long) parts[DUK_DATE_IDX_MINUTE],
	                     (long) parts[DUK_DATE_IDX_SECOND],
	                     (long) parts[DUK_DATE_IDX_MILLISECOND]));

	/* This assert depends on the input parts representing time inside
	 * the ECMAScript range.
	 */
	DUK_ASSERT(t2 + DUK__WEEKDAY_MOD_ADDER >= 0);
	parts[DUK_DATE_IDX_WEEKDAY] = (t2 + 4 + DUK__WEEKDAY_MOD_ADDER) % 7;  /* E5.1 Section 15.9.1.6 */
	DUK_ASSERT(parts[DUK_DATE_IDX_WEEKDAY] >= 0 && parts[DUK_DATE_IDX_WEEKDAY] <= 6);

	year = duk__year_from_day(t2, &day_in_year);
	day = day_in_year;
	is_leap = duk_bi_date_is_leap_year(year);
	for (month = 0; month < 12; month++) {
		dim = duk__days_in_month[month];
		if (month == 1 && is_leap) {
			dim++;
		}
		DUK_DDD(DUK_DDDPRINT("month=%ld, dim=%ld, day=%ld",
		                     (long) month, (long) dim, (long) day));
		if (day < dim) {
			break;
		}
		day -= dim;
	}
	DUK_DDD(DUK_DDDPRINT("final month=%ld", (long) month));
	DUK_ASSERT(month >= 0 && month <= 11);
	DUK_ASSERT(day >= 0 && day <= 31);

	/* Equivalent year mapping, used to avoid DST trouble when platform
	 * may fail to provide reasonable DST answers for dates outside the
	 * ordinary range (e.g. 1970-2038).  An equivalent year has the same
	 * leap-year-ness as the original year and begins on the same weekday
	 * (Jan 1).
	 *
	 * The year 2038 is avoided because there seem to be problems with it
	 * on some platforms.  The year 1970 is also avoided as there were
	 * practical problems with it; an equivalent year is used for it too,
	 * which breaks some DST computations for 1970 right now, see e.g.
	 * test-bi-date-tzoffset-brute-fi.js.
	 */
	if ((flags & DUK_DATE_FLAG_EQUIVYEAR) && (year < 1971 || year > 2037)) {
		DUK_ASSERT(is_leap == 0 || is_leap == 1);

		jan1_since_epoch = day_since_epoch - day_in_year;  /* day number for Jan 1 since epoch */
		DUK_ASSERT(jan1_since_epoch + DUK__WEEKDAY_MOD_ADDER >= 0);
		jan1_weekday = (jan1_since_epoch + 4 + DUK__WEEKDAY_MOD_ADDER) % 7;  /* E5.1 Section 15.9.1.6 */
		DUK_ASSERT(jan1_weekday >= 0 && jan1_weekday <= 6);
		arridx = jan1_weekday;
		if (is_leap) {
			arridx += 7;
		}
		DUK_ASSERT(arridx >= 0 && arridx < (duk_small_int_t) (sizeof(duk__date_equivyear) / sizeof(duk_uint8_t)));

		equiv_year = (duk_int_t) duk__date_equivyear[arridx] + 1970;
		year = equiv_year;
		DUK_DDD(DUK_DDDPRINT("equiv year mapping, year=%ld, day_in_year=%ld, day_since_epoch=%ld, "
		                     "jan1_since_epoch=%ld, jan1_weekday=%ld -> equiv year %ld",
		                     (long) year, (long) day_in_year, (long) day_since_epoch,
		                     (long) jan1_since_epoch, (long) jan1_weekday, (long) equiv_year));
	}

	parts[DUK_DATE_IDX_YEAR] = year;
	parts[DUK_DATE_IDX_MONTH] = month;
	parts[DUK_DATE_IDX_DAY] = day;

	if (flags & DUK_DATE_FLAG_ONEBASED) {
		parts[DUK_DATE_IDX_MONTH]++;  /* zero-based -> one-based */
		parts[DUK_DATE_IDX_DAY]++;    /* -""- */
	}

	if (dparts != NULL) {
		for (i = 0; i < DUK_DATE_IDX_NUM_PARTS; i++) {
			dparts[i] = (duk_double_t) parts[i];
		}
	}
}

/* Compute time value from (double) parts.  The parts can be either UTC
 * or local time; if local, they need to be (conceptually) converted into
 * UTC time.  The parts may represent valid or invalid time, and may be
 * wildly out of range (but may cancel each other and still come out in
 * the valid Date range).
 */
DUK_INTERNAL duk_double_t duk_bi_date_get_timeval_from_dparts(duk_double_t *dparts, duk_small_uint_t flags) {
#if defined(DUK_USE_PARANOID_DATE_COMPUTATION)
	/* See comments below on MakeTime why these are volatile. */
	volatile duk_double_t tmp_time;
	volatile duk_double_t tmp_day;
	volatile duk_double_t d;
#else
	duk_double_t tmp_time;
	duk_double_t tmp_day;
	duk_double_t d;
#endif
	duk_small_uint_t i;
	duk_int_t tzoff, tzoffprev1, tzoffprev2;

	/* Expects 'this' at top of stack on entry. */

	/* Coerce all finite parts with ToInteger().  ToInteger() must not
	 * be called for NaN/Infinity because it will convert e.g. NaN to
	 * zero.  If ToInteger() has already been called, this has no side
	 * effects and is idempotent.
	 *
	 * Don't read dparts[DUK_DATE_IDX_WEEKDAY]; it will cause Valgrind
	 * issues if the value is uninitialized.
	 */
	for (i = 0; i <= DUK_DATE_IDX_MILLISECOND; i++) {
		/* SCANBUILD: scan-build complains here about assigned value
		 * being garbage or undefined.  This is correct but operating
		 * on undefined values has no ill effect and is ignored by the
		 * caller in the case where this happens.
		 */
		d = dparts[i];
		if (DUK_ISFINITE(d)) {
			dparts[i] = duk_js_tointeger_number(d);
		}
	}

	/* Use explicit steps in computation to try to ensure that
	 * computation happens with intermediate results coerced to
	 * double values (instead of using something more accurate).
	 * E.g. E5.1 Section 15.9.1.11 requires use of IEEE 754
	 * rules (= ECMAScript '+' and '*' operators).
	 *
	 * Without 'volatile' even this approach fails on some platform
	 * and compiler combinations.  For instance, gcc 4.8.1 on Ubuntu
	 * 64-bit, with -m32 and without -std=c99, test-bi-date-canceling.js
	 * would fail because of some optimizations when computing tmp_time
	 * (MakeTime below).  Adding 'volatile' to tmp_time solved this
	 * particular problem (annoyingly, also adding debug prints or
	 * running the executable under valgrind hides it).
	 */

	/* MakeTime */
	tmp_time = 0.0;
	tmp_time += dparts[DUK_DATE_IDX_HOUR] * ((duk_double_t) DUK_DATE_MSEC_HOUR);
	tmp_time += dparts[DUK_DATE_IDX_MINUTE] * ((duk_double_t) DUK_DATE_MSEC_MINUTE);
	tmp_time += dparts[DUK_DATE_IDX_SECOND] * ((duk_double_t) DUK_DATE_MSEC_SECOND);
	tmp_time += dparts[DUK_DATE_IDX_MILLISECOND];

	/* MakeDay */
	tmp_day = duk__make_day(dparts[DUK_DATE_IDX_YEAR], dparts[DUK_DATE_IDX_MONTH], dparts[DUK_DATE_IDX_DAY]);

	/* MakeDate */
	d = tmp_day * ((duk_double_t) DUK_DATE_MSEC_DAY) + tmp_time;

	DUK_DDD(DUK_DDDPRINT("time=%lf day=%lf --> timeval=%lf",
	                     (double) tmp_time, (double) tmp_day, (double) d));

	/* Optional UTC conversion. */
	if (flags & DUK_DATE_FLAG_LOCALTIME) {
		/* DUK_USE_DATE_GET_LOCAL_TZOFFSET() needs to be called with a
		 * time value computed from UTC parts.  At this point we only
		 * have 'd' which is a time value computed from local parts, so
		 * it is off by the UTC-to-local time offset which we don't know
		 * yet.  The current solution for computing the UTC-to-local
		 * time offset is to iterate a few times and detect a fixed
		 * point or a two-cycle loop (or a sanity iteration limit),
		 * see test-bi-date-local-parts.js and test-bi-date-tzoffset-basic-fi.js.
		 *
		 * E5.1 Section 15.9.1.9:
		 * UTC(t) = t - LocalTZA - DaylightSavingTA(t - LocalTZA)
		 *
		 * For NaN/inf, DUK_USE_DATE_GET_LOCAL_TZOFFSET() returns 0.
		 */

#if 0
		/* Old solution: don't iterate, incorrect */
		tzoff = DUK_USE_DATE_GET_LOCAL_TZOFFSET(d);
		DUK_DDD(DUK_DDDPRINT("tzoffset w/o iteration, tzoff=%ld", (long) tzoff));
		d -= tzoff * 1000L;
		DUK_UNREF(tzoffprev1);
		DUK_UNREF(tzoffprev2);
#endif

		/* Iteration solution */
		tzoff = 0;
		tzoffprev1 = 999999999L;  /* invalid value which never matches */
		for (i = 0; i < DUK__LOCAL_TZOFFSET_MAXITER; i++) {
			tzoffprev2 = tzoffprev1;
			tzoffprev1 = tzoff;
			tzoff = DUK_USE_DATE_GET_LOCAL_TZOFFSET(d - tzoff * 1000L);
			DUK_DDD(DUK_DDDPRINT("tzoffset iteration, i=%d, tzoff=%ld, tzoffprev1=%ld tzoffprev2=%ld",
			                     (int) i, (long) tzoff, (long) tzoffprev1, (long) tzoffprev2));
			if (tzoff == tzoffprev1) {
				DUK_DDD(DUK_DDDPRINT("tzoffset iteration finished, i=%d, tzoff=%ld, tzoffprev1=%ld, tzoffprev2=%ld",
				                     (int) i, (long) tzoff, (long) tzoffprev1, (long) tzoffprev2));
				break;
			} else if (tzoff == tzoffprev2) {
				/* Two value cycle, see e.g. test-bi-date-tzoffset-basic-fi.js.
				 * In these cases, favor a higher tzoffset to get a consistent
				 * result which is independent of iteration count.  Not sure if
				 * this is a generically correct solution.
				 */
				DUK_DDD(DUK_DDDPRINT("tzoffset iteration two-value cycle, i=%d, tzoff=%ld, tzoffprev1=%ld, tzoffprev2=%ld",
				                     (int) i, (long) tzoff, (long) tzoffprev1, (long) tzoffprev2));
				if (tzoffprev1 > tzoff) {
					tzoff = tzoffprev1;
				}
				break;
			}
		}
		DUK_DDD(DUK_DDDPRINT("tzoffset iteration, tzoff=%ld", (long) tzoff));
		d -= tzoff * 1000L;
	}

	/* TimeClip(), which also handles Infinity -> NaN conversion */
	d = duk__timeclip(d);

	return d;
}

/*
 *  API oriented helpers
 */

/* Push 'this' binding, check that it is a Date object; then push the
 * internal time value.  At the end, stack is: [ ... this timeval ].
 * Returns the time value.  Local time adjustment is done if requested.
 */
DUK_LOCAL duk_double_t duk__push_this_get_timeval_tzoffset(duk_hthread *thr, duk_small_uint_t flags, duk_int_t *out_tzoffset) {
	duk_hobject *h;
	duk_double_t d;
	duk_int_t tzoffset = 0;

	duk_push_this(thr);
	h = duk_get_hobject(thr, -1);  /* XXX: getter with class check, useful in built-ins */
	if (h == NULL || DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_DATE) {
		DUK_ERROR_TYPE(thr, "expected Date");
		DUK_WO_NORETURN(return 0.0;);
	}

	duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
	d = duk_to_number_m1(thr);
	duk_pop(thr);

	if (DUK_ISNAN(d)) {
		if (flags & DUK_DATE_FLAG_NAN_TO_ZERO) {
			d = 0.0;
		}
		if (flags & DUK_DATE_FLAG_NAN_TO_RANGE_ERROR) {
			DUK_ERROR_RANGE(thr, "Invalid Date");
			DUK_WO_NORETURN(return 0.0;);
		}
	}
	/* if no NaN handling flag, may still be NaN here, but not Inf */
	DUK_ASSERT(!DUK_ISINF(d));

	if (flags & DUK_DATE_FLAG_LOCALTIME) {
		/* Note: DST adjustment is determined using UTC time.
		 * If 'd' is NaN, tzoffset will be 0.
		 */
		tzoffset = DUK_USE_DATE_GET_LOCAL_TZOFFSET(d);  /* seconds */
		d += tzoffset * 1000L;
	}
	if (out_tzoffset) {
		*out_tzoffset = tzoffset;
	}

	/* [ ... this ] */
	return d;
}

DUK_LOCAL duk_double_t duk__push_this_get_timeval(duk_hthread *thr, duk_small_uint_t flags) {
	return duk__push_this_get_timeval_tzoffset(thr, flags, NULL);
}

/* Set timeval to 'this' from dparts, push the new time value onto the
 * value stack and return 1 (caller can then tail call us).  Expects
 * the value stack to contain 'this' on the stack top.
 */
DUK_LOCAL duk_ret_t duk__set_this_timeval_from_dparts(duk_hthread *thr, duk_double_t *dparts, duk_small_uint_t flags) {
	duk_double_t d;

	/* [ ... this ] */

	d = duk_bi_date_get_timeval_from_dparts(dparts, flags);
	duk_push_number(thr, d);  /* -> [ ... this timeval_new ] */
	duk_dup_top(thr);         /* -> [ ... this timeval_new timeval_new ] */

	/* Must force write because e.g. .setYear() must work even when
	 * the Date instance is frozen.
	 */
	duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_W);

	/* Stack top: new time value, return 1 to allow tail calls. */
	return 1;
}

/* 'out_buf' must be at least DUK_BI_DATE_ISO8601_BUFSIZE long. */
DUK_LOCAL void duk__format_parts_iso8601(duk_int_t *parts, duk_int_t tzoffset, duk_small_uint_t flags, duk_uint8_t *out_buf) {
	char yearstr[8];   /* "-123456\0" */
	char tzstr[8];     /* "+11:22\0" */
	char sep = (flags & DUK_DATE_FLAG_SEP_T) ? DUK_ASC_UC_T : DUK_ASC_SPACE;

	DUK_ASSERT(parts[DUK_DATE_IDX_MONTH] >= 1 && parts[DUK_DATE_IDX_MONTH] <= 12);
	DUK_ASSERT(parts[DUK_DATE_IDX_DAY] >= 1 && parts[DUK_DATE_IDX_DAY] <= 31);
	DUK_ASSERT(parts[DUK_DATE_IDX_YEAR] >= -999999 && parts[DUK_DATE_IDX_YEAR] <= 999999);

	/* Note: %06d for positive value, %07d for negative value to include
	 * sign and 6 digits.
	 */
	DUK_SNPRINTF(yearstr,
	             sizeof(yearstr),
	             (parts[DUK_DATE_IDX_YEAR] >= 0 && parts[DUK_DATE_IDX_YEAR] <= 9999) ? "%04ld" :
	                    ((parts[DUK_DATE_IDX_YEAR] >= 0) ? "+%06ld" : "%07ld"),
	             (long) parts[DUK_DATE_IDX_YEAR]);
	yearstr[sizeof(yearstr) - 1] = (char) 0;

	if (flags & DUK_DATE_FLAG_LOCALTIME) {
		/* tzoffset seconds are dropped; 16 bits suffice for
		 * time offset in minutes
		 */
		const char *fmt;
		duk_small_int_t tmp, arg_hours, arg_minutes;

		if (tzoffset >= 0) {
			tmp = tzoffset;
			fmt = "+%02d:%02d";
		} else {
			tmp = -tzoffset;
			fmt = "-%02d:%02d";
		}
		tmp = tmp / 60;
		arg_hours = tmp / 60;
		arg_minutes = tmp % 60;
		DUK_ASSERT(arg_hours <= 24);  /* Even less is actually guaranteed for a valid tzoffset. */
		arg_hours = arg_hours & 0x3f;  /* For [0,24] this is a no-op, but fixes GCC 7 warning, see https://github.com/svaarala/duktape/issues/1602. */

		DUK_SNPRINTF(tzstr, sizeof(tzstr), fmt, (int) arg_hours, (int) arg_minutes);
		tzstr[sizeof(tzstr) - 1] = (char) 0;
	} else {
		tzstr[0] = DUK_ASC_UC_Z;
		tzstr[1] = (char) 0;
	}

	/* Unlike year, the other parts fit into 16 bits so %d format
	 * is portable.
	 */
	if ((flags & DUK_DATE_FLAG_TOSTRING_DATE) && (flags & DUK_DATE_FLAG_TOSTRING_TIME)) {
		DUK_SPRINTF((char *) out_buf, "%s-%02d-%02d%c%02d:%02d:%02d.%03d%s",
		            (const char *) yearstr, (int) parts[DUK_DATE_IDX_MONTH], (int) parts[DUK_DATE_IDX_DAY], (int) sep,
		            (int) parts[DUK_DATE_IDX_HOUR], (int) parts[DUK_DATE_IDX_MINUTE],
		            (int) parts[DUK_DATE_IDX_SECOND], (int) parts[DUK_DATE_IDX_MILLISECOND], (const char *) tzstr);
	} else if (flags & DUK_DATE_FLAG_TOSTRING_DATE) {
		DUK_SPRINTF((char *) out_buf, "%s-%02d-%02d",
		            (const char *) yearstr, (int) parts[DUK_DATE_IDX_MONTH], (int) parts[DUK_DATE_IDX_DAY]);
	} else {
		DUK_ASSERT(flags & DUK_DATE_FLAG_TOSTRING_TIME);
		DUK_SPRINTF((char *) out_buf, "%02d:%02d:%02d.%03d%s",
		            (int) parts[DUK_DATE_IDX_HOUR], (int) parts[DUK_DATE_IDX_MINUTE],
		            (int) parts[DUK_DATE_IDX_SECOND], (int) parts[DUK_DATE_IDX_MILLISECOND],
		            (const char *) tzstr);
	}
}

/* Helper for string conversion calls: check 'this' binding, get the
 * internal time value, and format date and/or time in a few formats.
 * Return value allows tail calls.
 */
DUK_LOCAL duk_ret_t duk__to_string_helper(duk_hthread *thr, duk_small_uint_t flags) {
	duk_double_t d;
	duk_int_t parts[DUK_DATE_IDX_NUM_PARTS];
	duk_int_t tzoffset;  /* seconds, doesn't fit into 16 bits */
	duk_bool_t rc;
	duk_uint8_t buf[DUK_BI_DATE_ISO8601_BUFSIZE];

	DUK_UNREF(rc);  /* unreferenced with some options */

	d = duk__push_this_get_timeval_tzoffset(thr, flags, &tzoffset);
	if (DUK_ISNAN(d)) {
		duk_push_hstring_stridx(thr, DUK_STRIDX_INVALID_DATE);
		return 1;
	}
	DUK_ASSERT(DUK_ISFINITE(d));

	/* formatters always get one-based month/day-of-month */
	duk_bi_date_timeval_to_parts(d, parts, NULL, DUK_DATE_FLAG_ONEBASED);
	DUK_ASSERT(parts[DUK_DATE_IDX_MONTH] >= 1 && parts[DUK_DATE_IDX_MONTH] <= 12);
	DUK_ASSERT(parts[DUK_DATE_IDX_DAY] >= 1 && parts[DUK_DATE_IDX_DAY] <= 31);

	if (flags & DUK_DATE_FLAG_TOSTRING_LOCALE) {
		/* try locale specific formatter; if it refuses to format the
		 * string, fall back to an ISO 8601 formatted value in local
		 * time.
		 */
#if defined(DUK_USE_DATE_FORMAT_STRING)
		/* Contract, either:
		 * - Push string to value stack and return 1
		 * - Don't push anything and return 0
		 */

		rc = DUK_USE_DATE_FORMAT_STRING(thr, parts, tzoffset, flags);
		if (rc != 0) {
			return 1;
		}
#else
		/* No locale specific formatter; this is OK, we fall back
		 * to ISO 8601.
		 */
#endif
	}

	/* Different calling convention than above used because the helper
	 * is shared.
	 */
	duk__format_parts_iso8601(parts, tzoffset, flags, buf);
	duk_push_string(thr, (const char *) buf);
	return 1;
}

/* Helper for component getter calls: check 'this' binding, get the
 * internal time value, split it into parts (either as UTC time or
 * local time), push a specified component as a return value to the
 * value stack and return 1 (caller can then tail call us).
 */
DUK_LOCAL duk_ret_t duk__get_part_helper(duk_hthread *thr, duk_small_uint_t flags_and_idx) {
	duk_double_t d;
	duk_int_t parts[DUK_DATE_IDX_NUM_PARTS];
	duk_small_uint_t idx_part = (duk_small_uint_t) (flags_and_idx >> DUK_DATE_FLAG_VALUE_SHIFT);  /* unpack args */

	DUK_ASSERT_DISABLE(idx_part >= 0);  /* unsigned */
	DUK_ASSERT(idx_part < DUK_DATE_IDX_NUM_PARTS);

	d = duk__push_this_get_timeval(thr, flags_and_idx);
	if (DUK_ISNAN(d)) {
		duk_push_nan(thr);
		return 1;
	}
	DUK_ASSERT(DUK_ISFINITE(d));

	duk_bi_date_timeval_to_parts(d, parts, NULL, flags_and_idx);  /* no need to mask idx portion */

	/* Setter APIs detect special year numbers (0...99) and apply a +1900
	 * only in certain cases.  The legacy getYear() getter applies -1900
	 * unconditionally.
	 */
	duk_push_int(thr, (flags_and_idx & DUK_DATE_FLAG_SUB1900) ? parts[idx_part] - 1900 : parts[idx_part]);
	return 1;
}

/* Helper for component setter calls: check 'this' binding, get the
 * internal time value, split it into parts (either as UTC time or
 * local time), modify one or more components as specified, recompute
 * the time value, set it as the internal value.  Finally, push the
 * new time value as a return value to the value stack and return 1
 * (caller can then tail call us).
 */
DUK_LOCAL duk_ret_t duk__set_part_helper(duk_hthread *thr, duk_small_uint_t flags_and_maxnargs) {
	duk_double_t d;
	duk_int_t parts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_idx_t nargs;
	duk_small_uint_t maxnargs = (duk_small_uint_t) (flags_and_maxnargs >> DUK_DATE_FLAG_VALUE_SHIFT);  /* unpack args */
	duk_small_uint_t idx_first, idx;
	duk_small_uint_t i;

	nargs = duk_get_top(thr);
	d = duk__push_this_get_timeval(thr, flags_and_maxnargs);
	DUK_ASSERT(DUK_ISFINITE(d) || DUK_ISNAN(d));

	if (DUK_ISFINITE(d)) {
		duk_bi_date_timeval_to_parts(d, parts, dparts, flags_and_maxnargs);
	} else {
		/* NaN timevalue: we need to coerce the arguments, but
		 * the resulting internal timestamp needs to remain NaN.
		 * This works but is not pretty: parts and dparts will
		 * be partially uninitialized, but we only write to them.
		 */
	}

	/*
	 *  Determining which datetime components to overwrite based on
	 *  stack arguments is a bit complicated, but important to factor
	 *  out from setters themselves for compactness.
	 *
	 *  If DUK_DATE_FLAG_TIMESETTER, maxnargs indicates setter type:
	 *
	 *   1 -> millisecond
	 *   2 -> second, [millisecond]
	 *   3 -> minute, [second], [millisecond]
	 *   4 -> hour, [minute], [second], [millisecond]
	 *
	 *  Else:
	 *
	 *   1 -> date
	 *   2 -> month, [date]
	 *   3 -> year, [month], [date]
	 *
	 *  By comparing nargs and maxnargs (and flags) we know which
	 *  components to override.  We rely on part index ordering.
	 */

	if (flags_and_maxnargs & DUK_DATE_FLAG_TIMESETTER) {
		DUK_ASSERT(maxnargs >= 1 && maxnargs <= 4);
		idx_first = DUK_DATE_IDX_MILLISECOND - (maxnargs - 1);
	} else {
		DUK_ASSERT(maxnargs >= 1 && maxnargs <= 3);
		idx_first = DUK_DATE_IDX_DAY - (maxnargs - 1);
	}
	DUK_ASSERT_DISABLE(idx_first >= 0);  /* unsigned */
	DUK_ASSERT(idx_first < DUK_DATE_IDX_NUM_PARTS);

	for (i = 0; i < maxnargs; i++) {
		if ((duk_idx_t) i >= nargs) {
			/* no argument given -> leave components untouched */
			break;
		}
		idx = idx_first + i;
		DUK_ASSERT_DISABLE(idx >= 0);  /* unsigned */
		DUK_ASSERT(idx < DUK_DATE_IDX_NUM_PARTS);

		if (idx == DUK_DATE_IDX_YEAR && (flags_and_maxnargs & DUK_DATE_FLAG_YEAR_FIXUP)) {
			duk__twodigit_year_fixup(thr, (duk_idx_t) i);
		}

		dparts[idx] = duk_to_number(thr, (duk_idx_t) i);

		if (idx == DUK_DATE_IDX_DAY) {
			/* Day-of-month is one-based in the API, but zero-based
			 * internally, so fix here.  Note that month is zero-based
			 * both in the API and internally.
			 */
			/* SCANBUILD: complains about use of uninitialized values.
			 * The complaint is correct, but operating in undefined
			 * values here is intentional in some cases and the caller
			 * ignores the results.
			 */
			dparts[idx] -= 1.0;
		}
	}

	/* Leaves new timevalue on stack top and returns 1, which is correct
	 * for part setters.
	 */
	if (DUK_ISFINITE(d)) {
		return duk__set_this_timeval_from_dparts(thr, dparts, flags_and_maxnargs);
	} else {
		/* Internal timevalue is already NaN, so don't touch it. */
		duk_push_nan(thr);
		return 1;
	}
}

/* Apply ToNumber() to specified index; if ToInteger(val) in [0,99], add
 * 1900 and replace value at idx_val.
 */
DUK_LOCAL void duk__twodigit_year_fixup(duk_hthread *thr, duk_idx_t idx_val) {
	duk_double_t d;

	/* XXX: idx_val would fit into 16 bits, but using duk_small_uint_t
	 * might not generate better code due to casting.
	 */

	/* E5 Sections 15.9.3.1, B.2.4, B.2.5 */
	duk_to_number(thr, idx_val);
	if (duk_is_nan(thr, idx_val)) {
		return;
	}
	duk_dup(thr, idx_val);
	duk_to_int(thr, -1);
	d = duk_get_number(thr, -1);  /* get as double to handle huge numbers correctly */
	if (d >= 0.0 && d <= 99.0) {
		d += 1900.0;
		duk_push_number(thr, d);
		duk_replace(thr, idx_val);
	}
	duk_pop(thr);
}

/* Set datetime parts from stack arguments, defaulting any missing values.
 * Day-of-week is not set; it is not required when setting the time value.
 */
DUK_LOCAL void duk__set_parts_from_args(duk_hthread *thr, duk_double_t *dparts, duk_idx_t nargs) {
	duk_double_t d;
	duk_small_uint_t i;
	duk_small_uint_t idx;

	/* Causes a ToNumber() coercion, but doesn't break coercion order since
	 * year is coerced first anyway.
	 */
	duk__twodigit_year_fixup(thr, 0);

	/* There are at most 7 args, but we use 8 here so that also
	 * DUK_DATE_IDX_WEEKDAY gets initialized (to zero) to avoid the potential
	 * for any Valgrind gripes later.
	 */
	for (i = 0; i < 8; i++) {
		/* Note: rely on index ordering */
		idx = DUK_DATE_IDX_YEAR + i;
		if ((duk_idx_t) i < nargs) {
			d = duk_to_number(thr, (duk_idx_t) i);
			if (idx == DUK_DATE_IDX_DAY) {
				/* Convert day from one-based to zero-based (internal).  This may
				 * cause the day part to be negative, which is OK.
				 */
				d -= 1.0;
			}
		} else {
			/* All components default to 0 except day-of-month which defaults
			 * to 1.  However, because our internal day-of-month is zero-based,
			 * it also defaults to zero here.
			 */
			d = 0.0;
		}
		dparts[idx] = d;
	}

	DUK_DDD(DUK_DDDPRINT("parts from args -> %lf %lf %lf %lf %lf %lf %lf %lf",
	                     (double) dparts[0], (double) dparts[1],
	                     (double) dparts[2], (double) dparts[3],
	                     (double) dparts[4], (double) dparts[5],
	                     (double) dparts[6], (double) dparts[7]));
}

/*
 *  Indirect magic value lookup for Date methods.
 *
 *  Date methods don't put their control flags into the function magic value
 *  because they wouldn't fit into a LIGHTFUNC's magic field.  Instead, the
 *  magic value is set to an index pointing to the array of control flags
 *  below.
 *
 *  This must be kept in strict sync with genbuiltins.py!
 */

static duk_uint16_t duk__date_magics[] = {
	/* 0: toString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_TOSTRING_TIME + DUK_DATE_FLAG_LOCALTIME,

	/* 1: toDateString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_LOCALTIME,

	/* 2: toTimeString */
	DUK_DATE_FLAG_TOSTRING_TIME + DUK_DATE_FLAG_LOCALTIME,

	/* 3: toLocaleString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_TOSTRING_TIME + DUK_DATE_FLAG_TOSTRING_LOCALE + DUK_DATE_FLAG_LOCALTIME,

	/* 4: toLocaleDateString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_TOSTRING_LOCALE + DUK_DATE_FLAG_LOCALTIME,

	/* 5: toLocaleTimeString */
	DUK_DATE_FLAG_TOSTRING_TIME + DUK_DATE_FLAG_TOSTRING_LOCALE + DUK_DATE_FLAG_LOCALTIME,

	/* 6: toUTCString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_TOSTRING_TIME,

	/* 7: toISOString */
	DUK_DATE_FLAG_TOSTRING_DATE + DUK_DATE_FLAG_TOSTRING_TIME + DUK_DATE_FLAG_NAN_TO_RANGE_ERROR + DUK_DATE_FLAG_SEP_T,

	/* 8: getFullYear */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_YEAR << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 9: getUTCFullYear */
	0 + (DUK_DATE_IDX_YEAR << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 10: getMonth */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_MONTH << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 11: getUTCMonth */
	0 + (DUK_DATE_IDX_MONTH << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 12: getDate */
	DUK_DATE_FLAG_ONEBASED + DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_DAY << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 13: getUTCDate */
	DUK_DATE_FLAG_ONEBASED + (DUK_DATE_IDX_DAY << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 14: getDay */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_WEEKDAY << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 15: getUTCDay */
	0 + (DUK_DATE_IDX_WEEKDAY << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 16: getHours */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_HOUR << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 17: getUTCHours */
	0 + (DUK_DATE_IDX_HOUR << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 18: getMinutes */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_MINUTE << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 19: getUTCMinutes */
	0 + (DUK_DATE_IDX_MINUTE << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 20: getSeconds */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_SECOND << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 21: getUTCSeconds */
	0 + (DUK_DATE_IDX_SECOND << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 22: getMilliseconds */
	DUK_DATE_FLAG_LOCALTIME + (DUK_DATE_IDX_MILLISECOND << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 23: getUTCMilliseconds */
	0 + (DUK_DATE_IDX_MILLISECOND << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 24: setMilliseconds */
	DUK_DATE_FLAG_TIMESETTER + DUK_DATE_FLAG_LOCALTIME + (1 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 25: setUTCMilliseconds */
	DUK_DATE_FLAG_TIMESETTER + (1 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 26: setSeconds */
	DUK_DATE_FLAG_TIMESETTER + DUK_DATE_FLAG_LOCALTIME + (2 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 27: setUTCSeconds */
	DUK_DATE_FLAG_TIMESETTER + (2 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 28: setMinutes */
	DUK_DATE_FLAG_TIMESETTER + DUK_DATE_FLAG_LOCALTIME + (3 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 29: setUTCMinutes */
	DUK_DATE_FLAG_TIMESETTER + (3 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 30: setHours */
	DUK_DATE_FLAG_TIMESETTER + DUK_DATE_FLAG_LOCALTIME + (4 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 31: setUTCHours */
	DUK_DATE_FLAG_TIMESETTER + (4 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 32: setDate */
	DUK_DATE_FLAG_LOCALTIME + (1 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 33: setUTCDate */
	0 + (1 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 34: setMonth */
	DUK_DATE_FLAG_LOCALTIME + (2 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 35: setUTCMonth */
	0 + (2 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 36: setFullYear */
	DUK_DATE_FLAG_NAN_TO_ZERO + DUK_DATE_FLAG_LOCALTIME + (3 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 37: setUTCFullYear */
	DUK_DATE_FLAG_NAN_TO_ZERO + (3 << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 38: getYear */
	DUK_DATE_FLAG_LOCALTIME + DUK_DATE_FLAG_SUB1900 + (DUK_DATE_IDX_YEAR << DUK_DATE_FLAG_VALUE_SHIFT),

	/* 39: setYear */
	DUK_DATE_FLAG_NAN_TO_ZERO + DUK_DATE_FLAG_YEAR_FIXUP + (3 << DUK_DATE_FLAG_VALUE_SHIFT),
};

DUK_LOCAL duk_small_uint_t duk__date_get_indirect_magic(duk_hthread *thr) {
	duk_small_uint_t magicidx = (duk_small_uint_t) duk_get_current_magic(thr);
	DUK_ASSERT(magicidx < (duk_small_int_t) (sizeof(duk__date_magics) / sizeof(duk_uint16_t)));
	return (duk_small_uint_t) duk__date_magics[magicidx];
}

#if defined(DUK_USE_DATE_BUILTIN)
/*
 *  Constructor calls
 */

DUK_INTERNAL duk_ret_t duk_bi_date_constructor(duk_hthread *thr) {
	duk_idx_t nargs = duk_get_top(thr);
	duk_bool_t is_cons = duk_is_constructor_call(thr);
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t d;

	DUK_DDD(DUK_DDDPRINT("Date constructor, nargs=%ld, is_cons=%ld", (long) nargs, (long) is_cons));

	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DATE),
	                              DUK_BIDX_DATE_PROTOTYPE);

	/* Unlike most built-ins, the internal [[PrimitiveValue]] of a Date
	 * is mutable.
	 */

	if (nargs == 0 || !is_cons) {
		d = duk__timeclip(duk_time_get_ecmascript_time_nofrac(thr));
		duk_push_number(thr, d);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_W);
		if (!is_cons) {
			/* called as a normal function: return new Date().toString() */
			duk_to_string(thr, -1);
		}
		return 1;
	} else if (nargs == 1) {
		const char *str;
		duk_to_primitive(thr, 0, DUK_HINT_NONE);
		str = duk_get_string_notsymbol(thr, 0);
		if (str) {
			duk__parse_string(thr, str);
			duk_replace(thr, 0);  /* may be NaN */
		}
		d = duk__timeclip(duk_to_number(thr, 0));  /* symbols fail here */
		duk_push_number(thr, d);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_W);
		return 1;
	}

	duk__set_parts_from_args(thr, dparts, nargs);

	/* Parts are in local time, convert when setting. */

	(void) duk__set_this_timeval_from_dparts(thr, dparts, DUK_DATE_FLAG_LOCALTIME /*flags*/);  /* -> [ ... this timeval ] */
	duk_pop(thr);  /* -> [ ... this ] */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_date_constructor_parse(duk_hthread *thr) {
	return duk__parse_string(thr, duk_to_string(thr, 0));
}

DUK_INTERNAL duk_ret_t duk_bi_date_constructor_utc(duk_hthread *thr) {
	duk_idx_t nargs = duk_get_top(thr);
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t d;

	/* Behavior for nargs < 2 is implementation dependent: currently we'll
	 * set a NaN time value (matching V8 behavior) in this case.
	 */

	if (nargs < 2) {
		duk_push_nan(thr);
	} else {
		duk__set_parts_from_args(thr, dparts, nargs);
		d = duk_bi_date_get_timeval_from_dparts(dparts, 0 /*flags*/);
		duk_push_number(thr, d);
	}
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_date_constructor_now(duk_hthread *thr) {
	duk_double_t d;

	d = duk_time_get_ecmascript_time_nofrac(thr);
	DUK_ASSERT(duk_double_equals(duk__timeclip(d), d));  /* TimeClip() should never be necessary */
	duk_push_number(thr, d);
	return 1;
}

/*
 *  String/JSON conversions
 *
 *  Human readable conversions are now basically ISO 8601 with a space
 *  (instead of 'T') as the date/time separator.  This is a good baseline
 *  and is platform independent.
 *
 *  A shared native helper to provide many conversions.  Magic value contains
 *  a set of flags.  The helper provides:
 *
 *    toString()
 *    toDateString()
 *    toTimeString()
 *    toLocaleString()
 *    toLocaleDateString()
 *    toLocaleTimeString()
 *    toUTCString()
 *    toISOString()
 *
 *  Notes:
 *
 *    - Date.prototype.toGMTString() and Date.prototype.toUTCString() are
 *      required to be the same ECMAScript function object (!), so it is
 *      omitted from here.
 *
 *    - Date.prototype.toUTCString(): E5.1 specification does not require a
 *      specific format, but result should be human readable.  The
 *      specification suggests using ISO 8601 format with a space (instead
 *      of 'T') separator if a more human readable format is not available.
 *
 *    - Date.prototype.toISOString(): unlike other conversion functions,
 *      toISOString() requires a RangeError for invalid date values.
 */

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_tostring_shared(duk_hthread *thr) {
	duk_small_uint_t flags = duk__date_get_indirect_magic(thr);
	return duk__to_string_helper(thr, flags);
}

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_value_of(duk_hthread *thr) {
	/* This native function is also used for Date.prototype.getTime()
	 * as their behavior is identical.
	 */

	duk_double_t d = duk__push_this_get_timeval(thr, 0 /*flags*/);  /* -> [ this ] */
	DUK_ASSERT(DUK_ISFINITE(d) || DUK_ISNAN(d));
	duk_push_number(thr, d);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_to_json(duk_hthread *thr) {
	/* Note: toJSON() is a generic function which works even if 'this'
	 * is not a Date.  The sole argument is ignored.
	 */

	duk_push_this(thr);
	duk_to_object(thr, -1);

	duk_dup_top(thr);
	duk_to_primitive(thr, -1, DUK_HINT_NUMBER);
	if (duk_is_number(thr, -1)) {
		duk_double_t d = duk_get_number(thr, -1);
		if (!DUK_ISFINITE(d)) {
			duk_push_null(thr);
			return 1;
		}
	}
	duk_pop(thr);

	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_TO_ISO_STRING);
	duk_dup_m2(thr);  /* -> [ O toIsoString O ] */
	duk_call_method(thr, 0);
	return 1;
}

/*
 *  Getters.
 *
 *  Implementing getters is quite easy.  The internal time value is either
 *  NaN, or represents milliseconds (without fractions) from Jan 1, 1970.
 *  The internal time value can be converted to integer parts, and each
 *  part will be normalized and will fit into a 32-bit signed integer.
 *
 *  A shared native helper to provide all getters.  Magic value contains
 *  a set of flags and also packs the date component index argument.  The
 *  helper provides:
 *
 *    getFullYear()
 *    getUTCFullYear()
 *    getMonth()
 *    getUTCMonth()
 *    getDate()
 *    getUTCDate()
 *    getDay()
 *    getUTCDay()
 *    getHours()
 *    getUTCHours()
 *    getMinutes()
 *    getUTCMinutes()
 *    getSeconds()
 *    getUTCSeconds()
 *    getMilliseconds()
 *    getUTCMilliseconds()
 *    getYear()
 *
 *  Notes:
 *
 *    - Date.prototype.getDate(): 'date' means day-of-month, and is
 *      zero-based in internal calculations but public API expects it to
 *      be one-based.
 *
 *    - Date.prototype.getTime() and Date.prototype.valueOf() have identical
 *      behavior.  They have separate function objects, but share the same C
 *      function (duk_bi_date_prototype_value_of).
 */

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_get_shared(duk_hthread *thr) {
	duk_small_uint_t flags_and_idx = duk__date_get_indirect_magic(thr);
	return duk__get_part_helper(thr, flags_and_idx);
}

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_get_timezone_offset(duk_hthread *thr) {
	/*
	 *  Return (t - LocalTime(t)) in minutes:
	 *
	 *    t - LocalTime(t) = t - (t + LocalTZA + DaylightSavingTA(t))
	 *                     = -(LocalTZA + DaylightSavingTA(t))
	 *
	 *  where DaylightSavingTA() is checked for time 't'.
	 *
	 *  Note that the sign of the result is opposite to common usage,
	 *  e.g. for EE(S)T which normally is +2h or +3h from UTC, this
	 *  function returns -120 or -180.
	 *
	 */

	duk_double_t d;
	duk_int_t tzoffset;

	/* Note: DST adjustment is determined using UTC time. */
	d = duk__push_this_get_timeval(thr, 0 /*flags*/);
	DUK_ASSERT(DUK_ISFINITE(d) || DUK_ISNAN(d));
	if (DUK_ISNAN(d)) {
		duk_push_nan(thr);
	} else {
		DUK_ASSERT(DUK_ISFINITE(d));
		tzoffset = DUK_USE_DATE_GET_LOCAL_TZOFFSET(d);
		duk_push_int(thr, -tzoffset / 60);
	}
	return 1;
}

/*
 *  Setters.
 *
 *  Setters are a bit more complicated than getters.  Component setters
 *  break down the current time value into its (normalized) component
 *  parts, replace one or more components with -unnormalized- new values,
 *  and the components are then converted back into a time value.  As an
 *  example of using unnormalized values:
 *
 *    var d = new Date(1234567890);
 *
 *  is equivalent to:
 *
 *    var d = new Date(0);
 *    d.setUTCMilliseconds(1234567890);
 *
 *  A shared native helper to provide almost all setters.  Magic value
 *  contains a set of flags and also packs the "maxnargs" argument.  The
 *  helper provides:
 *
 *    setMilliseconds()
 *    setUTCMilliseconds()
 *    setSeconds()
 *    setUTCSeconds()
 *    setMinutes()
 *    setUTCMinutes()
 *    setHours()
 *    setUTCHours()
 *    setDate()
 *    setUTCDate()
 *    setMonth()
 *    setUTCMonth()
 *    setFullYear()
 *    setUTCFullYear()
 *    setYear()
 *
 *  Notes:
 *
 *    - Date.prototype.setYear() (Section B addition): special year check
 *      is omitted.  NaN / Infinity will just flow through and ultimately
 *      result in a NaN internal time value.
 *
 *    - Date.prototype.setYear() does not have optional arguments for
 *      setting month and day-in-month (like setFullYear()), but we indicate
 *      'maxnargs' to be 3 to get the year written to the correct component
 *      index in duk__set_part_helper().  The function has nargs == 1, so only
 *      the year will be set regardless of actual argument count.
 */

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_set_shared(duk_hthread *thr) {
	duk_small_uint_t flags_and_maxnargs = duk__date_get_indirect_magic(thr);
	return duk__set_part_helper(thr, flags_and_maxnargs);
}

DUK_INTERNAL duk_ret_t duk_bi_date_prototype_set_time(duk_hthread *thr) {
	duk_double_t d;

	(void) duk__push_this_get_timeval(thr, 0 /*flags*/); /* -> [ timeval this ] */
	d = duk__timeclip(duk_to_number(thr, 0));
	duk_push_number(thr, d);
	duk_dup_top(thr);
	/* Must force write because .setTime() must work even when
	 * the Date instance is frozen.
	 */
	duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_W);
	/* -> [ timeval this timeval ] */

	return 1;
}

/*
 *  Misc.
 */

#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_date_prototype_toprimitive(duk_hthread *thr) {
	duk_size_t hintlen;
	const char *hintstr;
	duk_int_t hint;

	/* Invokes OrdinaryToPrimitive() with suitable hint.  Note that the
	 * method is generic, and works on non-Date arguments too.
	 *
	 * https://www.ecma-international.org/ecma-262/6.0/#sec-date.prototype-@@toprimitive
	 */

	duk_push_this(thr);
	duk_require_object(thr, -1);
	DUK_ASSERT_TOP(thr, 2);

	hintstr = duk_require_lstring(thr, 0, &hintlen);
	if ((hintlen == 6 && DUK_STRCMP(hintstr, "string") == 0) ||
	    (hintlen == 7 && DUK_STRCMP(hintstr, "default") == 0)) {
		hint = DUK_HINT_STRING;
	} else if (hintlen == 6 && DUK_STRCMP(hintstr, "number") == 0) {
		hint = DUK_HINT_NUMBER;
	} else {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	duk_to_primitive_ordinary(thr, -1, hint);
	return 1;
}
#endif  /* DUK_USE_SYMBOL_BUILTIN */

#endif  /* DUK_USE_DATE_BUILTIN */

/* automatic undefs */
#undef DUK__CF_ACCEPT
#undef DUK__CF_ACCEPT_NUL
#undef DUK__CF_NEG
#undef DUK__DPRINT_DPARTS
#undef DUK__DPRINT_PARTS
#undef DUK__DPRINT_PARTS_AND_DPARTS
#undef DUK__LOCAL_TZOFFSET_MAXITER
#undef DUK__NUM_ISO8601_PARSER_PARTS
#undef DUK__PACK_RULE
#undef DUK__PI_DAY
#undef DUK__PI_HOUR
#undef DUK__PI_MILLISECOND
#undef DUK__PI_MINUTE
#undef DUK__PI_MONTH
#undef DUK__PI_SECOND
#undef DUK__PI_TZHOUR
#undef DUK__PI_TZMINUTE
#undef DUK__PI_YEAR
#undef DUK__PM_DAY
#undef DUK__PM_HOUR
#undef DUK__PM_MILLISECOND
#undef DUK__PM_MINUTE
#undef DUK__PM_MONTH
#undef DUK__PM_SECOND
#undef DUK__PM_TZHOUR
#undef DUK__PM_TZMINUTE
#undef DUK__PM_YEAR
#undef DUK__RULE_MASK_PART_SEP
#undef DUK__SI_COLON
#undef DUK__SI_MINUS
#undef DUK__SI_NUL
#undef DUK__SI_PERIOD
#undef DUK__SI_PLUS
#undef DUK__SI_SPACE
#undef DUK__SI_T
#undef DUK__SI_Z
#undef DUK__SM_COLON
#undef DUK__SM_MINUS
#undef DUK__SM_NUL
#undef DUK__SM_PERIOD
#undef DUK__SM_PLUS
#undef DUK__SM_SPACE
#undef DUK__SM_T
#undef DUK__SM_Z
#undef DUK__UNPACK_RULE
#undef DUK__WEEKDAY_MOD_ADDER
#undef DUK__YEAR
/*
 *  Unix-like Date providers
 *
 *  Generally useful Unix / POSIX / ANSI Date providers.
 */

/* #include duk_internal.h -> already included */

/* The necessary #includes are in place in duk_config.h. */

/* Buffer sizes for some UNIX calls.  Larger than strictly necessary
 * to avoid Valgrind errors.
 */
#define DUK__STRPTIME_BUF_SIZE  64
#define DUK__STRFTIME_BUF_SIZE  64

#if defined(DUK_USE_DATE_NOW_GETTIMEOFDAY)
/* Get current ECMAScript time (= UNIX/Posix time, but in milliseconds). */
DUK_INTERNAL duk_double_t duk_bi_date_get_now_gettimeofday(void) {
	struct timeval tv;
	duk_double_t d;

	if (gettimeofday(&tv, NULL) != 0) {
		DUK_D(DUK_DPRINT("gettimeofday() failed"));
		return 0.0;
	}

	/* As of Duktape 2.2.0 allow fractions. */
	d = ((duk_double_t) tv.tv_sec) * 1000.0 +
	    ((duk_double_t) tv.tv_usec) / 1000.0;

	return d;
}
#endif  /* DUK_USE_DATE_NOW_GETTIMEOFDAY */

#if defined(DUK_USE_DATE_NOW_TIME)
/* Not a very good provider: only full seconds are available. */
DUK_INTERNAL duk_double_t duk_bi_date_get_now_time(void) {
	time_t t;

	t = time(NULL);
	if (t == (time_t) -1) {
		DUK_D(DUK_DPRINT("time() failed"));
		return 0.0;
	}
	return ((duk_double_t) t) * 1000.0;
}
#endif  /* DUK_USE_DATE_NOW_TIME */

#if defined(DUK_USE_DATE_TZO_GMTIME) || defined(DUK_USE_DATE_TZO_GMTIME_R) || defined(DUK_USE_DATE_TZO_GMTIME_S)
/* Get local time offset (in seconds) for a certain (UTC) instant 'd'. */
DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_gmtime(duk_double_t d) {
	time_t t, t1, t2;
	duk_int_t parts[DUK_DATE_IDX_NUM_PARTS];
	duk_double_t dparts[DUK_DATE_IDX_NUM_PARTS];
	struct tm tms[2];
#if defined(DUK_USE_DATE_TZO_GMTIME)
	struct tm *tm_ptr;
#endif

	/* For NaN/inf, the return value doesn't matter. */
	if (!DUK_ISFINITE(d)) {
		return 0;
	}

	/* If not within ECMAScript range, some integer time calculations
	 * won't work correctly (and some asserts will fail), so bail out
	 * if so.  This fixes test-bug-date-insane-setyear.js.  There is
	 * a +/- 24h leeway in this range check to avoid a test262 corner
	 * case documented in test-bug-date-timeval-edges.js.
	 */
	if (!duk_bi_date_timeval_in_leeway_range(d)) {
		DUK_DD(DUK_DDPRINT("timeval not within valid range, skip tzoffset computation to avoid integer overflows"));
		return 0;
	}

	/*
	 *  This is a bit tricky to implement portably.  The result depends
	 *  on the timestamp (specifically, DST depends on the timestamp).
	 *  If e.g. UNIX APIs are used, they'll have portability issues with
	 *  very small and very large years.
	 *
	 *  Current approach:
	 *
	 *  - Stay within portable UNIX limits by using equivalent year mapping.
	 *    Avoid year 1970 and 2038 as some conversions start to fail, at
	 *    least on some platforms.  Avoiding 1970 means that there are
	 *    currently DST discrepancies for 1970.
	 *
	 *  - Create a UTC and local time breakdowns from 't'.  Then create
	 *    a time_t using gmtime() and localtime() and compute the time
	 *    difference between the two.
	 *
	 *  Equivalent year mapping (E5 Section 15.9.1.8):
	 *
	 *    If the host environment provides functionality for determining
	 *    daylight saving time, the implementation of ECMAScript is free
	 *    to map the year in question to an equivalent year (same
	 *    leap-year-ness and same starting week day for the year) for which
	 *    the host environment provides daylight saving time information.
	 *    The only restriction is that all equivalent years should produce
	 *    the same result.
	 *
	 *  This approach is quite reasonable but not entirely correct, e.g.
	 *  the specification also states (E5 Section 15.9.1.8):
	 *
	 *    The implementation of ECMAScript should not try to determine
	 *    whether the exact time was subject to daylight saving time, but
	 *    just whether daylight saving time would have been in effect if
	 *    the _current daylight saving time algorithm_ had been used at the
	 *    time.  This avoids complications such as taking into account the
	 *    years that the locale observed daylight saving time year round.
	 *
	 *  Since we rely on the platform APIs for conversions between local
	 *  time and UTC, we can't guarantee the above.  Rather, if the platform
	 *  has historical DST rules they will be applied.  This seems to be the
	 *  general preferred direction in ECMAScript standardization (or at least
	 *  implementations) anyway, and even the equivalent year mapping should
	 *  be disabled if the platform is known to handle DST properly for the
	 *  full ECMAScript range.
	 *
	 *  The following has useful discussion and links:
	 *
	 *    https://bugzilla.mozilla.org/show_bug.cgi?id=351066
	 */

	duk_bi_date_timeval_to_parts(d, parts, dparts, DUK_DATE_FLAG_EQUIVYEAR /*flags*/);
	DUK_ASSERT(parts[DUK_DATE_IDX_YEAR] >= 1970 && parts[DUK_DATE_IDX_YEAR] <= 2038);

	d = duk_bi_date_get_timeval_from_dparts(dparts, 0 /*flags*/);
	DUK_ASSERT(d >= 0 && d < 2147483648.0 * 1000.0);  /* unsigned 31-bit range */
	t = (time_t) (d / 1000.0);
	DUK_DDD(DUK_DDDPRINT("timeval: %lf -> time_t %ld", (double) d, (long) t));

	duk_memzero((void *) tms, sizeof(struct tm) * 2);

#if defined(DUK_USE_DATE_TZO_GMTIME_R)
	(void) gmtime_r(&t, &tms[0]);
	(void) localtime_r(&t, &tms[1]);
#elif defined(DUK_USE_DATE_TZO_GMTIME_S)
	(void) gmtime_s(&t, &tms[0]);
	(void) localtime_s(&t, &tms[1]);
#elif defined(DUK_USE_DATE_TZO_GMTIME)
	tm_ptr = gmtime(&t);
	duk_memcpy((void *) &tms[0], tm_ptr, sizeof(struct tm));
	tm_ptr = localtime(&t);
	duk_memcpy((void *) &tms[1], tm_ptr, sizeof(struct tm));
#else
#error internal error
#endif
	DUK_DDD(DUK_DDDPRINT("gmtime result: tm={sec:%ld,min:%ld,hour:%ld,mday:%ld,mon:%ld,year:%ld,"
	                     "wday:%ld,yday:%ld,isdst:%ld}",
	                     (long) tms[0].tm_sec, (long) tms[0].tm_min, (long) tms[0].tm_hour,
	                     (long) tms[0].tm_mday, (long) tms[0].tm_mon, (long) tms[0].tm_year,
	                     (long) tms[0].tm_wday, (long) tms[0].tm_yday, (long) tms[0].tm_isdst));
	DUK_DDD(DUK_DDDPRINT("localtime result: tm={sec:%ld,min:%ld,hour:%ld,mday:%ld,mon:%ld,year:%ld,"
	                     "wday:%ld,yday:%ld,isdst:%ld}",
	                     (long) tms[1].tm_sec, (long) tms[1].tm_min, (long) tms[1].tm_hour,
	                     (long) tms[1].tm_mday, (long) tms[1].tm_mon, (long) tms[1].tm_year,
	                     (long) tms[1].tm_wday, (long) tms[1].tm_yday, (long) tms[1].tm_isdst));

	/* tm_isdst is both an input and an output to mktime(), use 0 to
	 * avoid DST handling in mktime():
	 * - https://github.com/svaarala/duktape/issues/406
	 * - http://stackoverflow.com/questions/8558919/mktime-and-tm-isdst
	 */
	tms[0].tm_isdst = 0;
	tms[1].tm_isdst = 0;
	t1 = mktime(&tms[0]);  /* UTC */
	t2 = mktime(&tms[1]);  /* local */
	if (t1 == (time_t) -1 || t2 == (time_t) -1) {
		/* This check used to be for (t < 0) but on some platforms
		 * time_t is unsigned and apparently the proper way to detect
		 * an mktime() error return is the cast above.  See e.g.:
		 * http://pubs.opengroup.org/onlinepubs/009695299/functions/mktime.html
		 */
		goto mktime_error;
	}
	DUK_DDD(DUK_DDDPRINT("t1=%ld (utc), t2=%ld (local)", (long) t1, (long) t2));

	/* Compute final offset in seconds, positive if local time ahead of
	 * UTC (returned value is UTC-to-local offset).
	 *
	 * difftime() returns a double, so coercion to int generates quite
	 * a lot of code.  Direct subtraction is not portable, however.
	 * XXX: allow direct subtraction on known platforms.
	 */
#if 0
	return (duk_int_t) (t2 - t1);
#endif
	return (duk_int_t) difftime(t2, t1);

 mktime_error:
	/* XXX: return something more useful, so that caller can throw? */
	DUK_D(DUK_DPRINT("mktime() failed, d=%lf", (double) d));
	return 0;
}
#endif  /* DUK_USE_DATE_TZO_GMTIME */

#if defined(DUK_USE_DATE_PRS_STRPTIME)
DUK_INTERNAL duk_bool_t duk_bi_date_parse_string_strptime(duk_hthread *thr, const char *str) {
	struct tm tm;
	time_t t;
	char buf[DUK__STRPTIME_BUF_SIZE];

	/* Copy to buffer with slack to avoid Valgrind gripes from strptime. */
	DUK_ASSERT(str != NULL);
	duk_memzero(buf, sizeof(buf));  /* valgrind whine without this */
	DUK_SNPRINTF(buf, sizeof(buf), "%s", (const char *) str);
	buf[sizeof(buf) - 1] = (char) 0;

	DUK_DDD(DUK_DDDPRINT("parsing: '%s'", (const char *) buf));

	duk_memzero(&tm, sizeof(tm));
	if (strptime((const char *) buf, "%c", &tm) != NULL) {
		DUK_DDD(DUK_DDDPRINT("before mktime: tm={sec:%ld,min:%ld,hour:%ld,mday:%ld,mon:%ld,year:%ld,"
		                     "wday:%ld,yday:%ld,isdst:%ld}",
		                     (long) tm.tm_sec, (long) tm.tm_min, (long) tm.tm_hour,
		                     (long) tm.tm_mday, (long) tm.tm_mon, (long) tm.tm_year,
		                     (long) tm.tm_wday, (long) tm.tm_yday, (long) tm.tm_isdst));
		tm.tm_isdst = -1;  /* negative: dst info not available */

		t = mktime(&tm);
		DUK_DDD(DUK_DDDPRINT("mktime() -> %ld", (long) t));
		if (t >= 0) {
			duk_push_number(thr, ((duk_double_t) t) * 1000.0);
			return 1;
		}
	}

	return 0;
}
#endif  /* DUK_USE_DATE_PRS_STRPTIME */

#if defined(DUK_USE_DATE_PRS_GETDATE)
DUK_INTERNAL duk_bool_t duk_bi_date_parse_string_getdate(duk_hthread *thr, const char *str) {
	struct tm tm;
	duk_small_int_t rc;
	time_t t;

	/* For this to work, DATEMSK must be set, so this is not very
	 * convenient for an embeddable interpreter.
	 */

	duk_memzero(&tm, sizeof(struct tm));
	rc = (duk_small_int_t) getdate_r(str, &tm);
	DUK_DDD(DUK_DDDPRINT("getdate_r() -> %ld", (long) rc));

	if (rc == 0) {
		t = mktime(&tm);
		DUK_DDD(DUK_DDDPRINT("mktime() -> %ld", (long) t));
		if (t >= 0) {
			duk_push_number(thr, (duk_double_t) t);
			return 1;
		}
	}

	return 0;
}
#endif  /* DUK_USE_DATE_PRS_GETDATE */

#if defined(DUK_USE_DATE_FMT_STRFTIME)
DUK_INTERNAL duk_bool_t duk_bi_date_format_parts_strftime(duk_hthread *thr, duk_int_t *parts, duk_int_t tzoffset, duk_small_uint_t flags) {
	char buf[DUK__STRFTIME_BUF_SIZE];
	struct tm tm;
	const char *fmt;

	DUK_UNREF(tzoffset);

	/* If the platform doesn't support the entire ECMAScript range, we need
	 * to return 0 so that the caller can fall back to the default formatter.
	 *
	 * For now, assume that if time_t is 8 bytes or more, the whole ECMAScript
	 * range is supported.  For smaller time_t values (4 bytes in practice),
	 * assumes that the signed 32-bit range is supported.
	 *
	 * XXX: detect this more correctly per platform.  The size of time_t is
	 * probably not an accurate guarantee of strftime() supporting or not
	 * supporting a large time range (the full ECMAScript range).
	 */
	if (sizeof(time_t) < 8 &&
	    (parts[DUK_DATE_IDX_YEAR] < 1970 || parts[DUK_DATE_IDX_YEAR] > 2037)) {
		/* be paranoid for 32-bit time values (even avoiding negative ones) */
		return 0;
	}

	duk_memzero(&tm, sizeof(tm));
	tm.tm_sec = parts[DUK_DATE_IDX_SECOND];
	tm.tm_min = parts[DUK_DATE_IDX_MINUTE];
	tm.tm_hour = parts[DUK_DATE_IDX_HOUR];
	tm.tm_mday = parts[DUK_DATE_IDX_DAY];       /* already one-based */
	tm.tm_mon = parts[DUK_DATE_IDX_MONTH] - 1;  /* one-based -> zero-based */
	tm.tm_year = parts[DUK_DATE_IDX_YEAR] - 1900;
	tm.tm_wday = parts[DUK_DATE_IDX_WEEKDAY];
	tm.tm_isdst = 0;

	duk_memzero(buf, sizeof(buf));
	if ((flags & DUK_DATE_FLAG_TOSTRING_DATE) && (flags & DUK_DATE_FLAG_TOSTRING_TIME)) {
		fmt = "%c";
	} else if (flags & DUK_DATE_FLAG_TOSTRING_DATE) {
		fmt = "%x";
	} else {
		DUK_ASSERT(flags & DUK_DATE_FLAG_TOSTRING_TIME);
		fmt = "%X";
	}
	(void) strftime(buf, sizeof(buf) - 1, fmt, &tm);
	DUK_ASSERT(buf[sizeof(buf) - 1] == 0);

	duk_push_string(thr, buf);
	return 1;
}
#endif  /* DUK_USE_DATE_FMT_STRFTIME */

#if defined(DUK_USE_GET_MONOTONIC_TIME_CLOCK_GETTIME)
DUK_INTERNAL duk_double_t duk_bi_date_get_monotonic_time_clock_gettime(void) {
	struct timespec ts;

	if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
		return (duk_double_t) ts.tv_sec * 1000.0 + (duk_double_t) ts.tv_nsec / 1000000.0;
	} else {
		DUK_D(DUK_DPRINT("clock_gettime(CLOCK_MONOTONIC) failed"));
		return 0.0;
	}
}
#endif

/* automatic undefs */
#undef DUK__STRFTIME_BUF_SIZE
#undef DUK__STRPTIME_BUF_SIZE
/*
 *  Windows Date providers
 *
 *  Platform specific links:
 *
 *    - http://msdn.microsoft.com/en-us/library/windows/desktop/ms725473(v=vs.85).aspx
 */

/* #include duk_internal.h -> already included */

/* The necessary #includes are in place in duk_config.h. */

#if defined(DUK_USE_DATE_NOW_WINDOWS) || defined(DUK_USE_DATE_TZO_WINDOWS)
/* Shared Windows helpers. */
DUK_LOCAL void duk__convert_systime_to_ularge(const SYSTEMTIME *st, ULARGE_INTEGER *res) {
	FILETIME ft;
	if (SystemTimeToFileTime(st, &ft) == 0) {
		DUK_D(DUK_DPRINT("SystemTimeToFileTime() failed, returning 0"));
		res->QuadPart = 0;
	} else {
		res->LowPart = ft.dwLowDateTime;
		res->HighPart = ft.dwHighDateTime;
	}
}

#if defined(DUK_USE_DATE_NOW_WINDOWS_SUBMS)
DUK_LOCAL void duk__convert_filetime_to_ularge(const FILETIME *ft, ULARGE_INTEGER *res) {
	res->LowPart = ft->dwLowDateTime;
	res->HighPart = ft->dwHighDateTime;
}
#endif  /* DUK_USE_DATE_NOW_WINDOWS_SUBMS */

DUK_LOCAL void duk__set_systime_jan1970(SYSTEMTIME *st) {
	duk_memzero((void *) st, sizeof(*st));
	st->wYear = 1970;
	st->wMonth = 1;
	st->wDayOfWeek = 4;  /* not sure whether or not needed; Thursday */
	st->wDay = 1;
	DUK_ASSERT(st->wHour == 0);
	DUK_ASSERT(st->wMinute == 0);
	DUK_ASSERT(st->wSecond == 0);
	DUK_ASSERT(st->wMilliseconds == 0);
}
#endif  /* defined(DUK_USE_DATE_NOW_WINDOWS) || defined(DUK_USE_DATE_TZO_WINDOWS) */

#if defined(DUK_USE_DATE_NOW_WINDOWS)
DUK_INTERNAL duk_double_t duk_bi_date_get_now_windows(void) {
	/* Suggested step-by-step method from documentation of RtlTimeToSecondsSince1970:
	 * http://msdn.microsoft.com/en-us/library/windows/desktop/ms724928(v=vs.85).aspx
	 */
	SYSTEMTIME st1, st2;
	ULARGE_INTEGER tmp1, tmp2;

	GetSystemTime(&st1);
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st1, &tmp1);

	duk__set_systime_jan1970(&st2);
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st2, &tmp2);

	/* Difference is in 100ns units, convert to milliseconds, keeping
	 * fractions since Duktape 2.2.0.  This is only theoretical because
	 * SYSTEMTIME is limited to milliseconds.
	 */
	return (duk_double_t) ((LONGLONG) tmp1.QuadPart - (LONGLONG) tmp2.QuadPart) / 10000.0;
}
#endif  /* DUK_USE_DATE_NOW_WINDOWS */

#if defined(DUK_USE_DATE_NOW_WINDOWS_SUBMS)
DUK_INTERNAL duk_double_t duk_bi_date_get_now_windows_subms(void) {
	/* Variant of the basic algorithm using GetSystemTimePreciseAsFileTime()
	 * for more accuracy.
	 */
	FILETIME ft1;
	SYSTEMTIME st2;
	ULARGE_INTEGER tmp1, tmp2;

	GetSystemTimePreciseAsFileTime(&ft1);
	duk__convert_filetime_to_ularge((const FILETIME *) &ft1, &tmp1);

	duk__set_systime_jan1970(&st2);
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st2, &tmp2);

	/* Difference is in 100ns units, convert to milliseconds, keeping
	 * fractions since Duktape 2.2.0.
	 */
	return (duk_double_t) ((LONGLONG) tmp1.QuadPart - (LONGLONG) tmp2.QuadPart) / 10000.0;
}
#endif  /* DUK_USE_DATE_NOW_WINDOWS */

#if defined(DUK_USE_DATE_TZO_WINDOWS)
DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows(duk_double_t d) {
	SYSTEMTIME st1;
	SYSTEMTIME st2;
	SYSTEMTIME st3;
	ULARGE_INTEGER tmp1;
	ULARGE_INTEGER tmp2;
	ULARGE_INTEGER tmp3;
	FILETIME ft1;

	/* XXX: handling of timestamps outside Windows supported range.
	 * How does Windows deal with dates before 1600?  Does windows
	 * support all ECMAScript years (like -200000 and +200000)?
	 * Should equivalent year mapping be used here too?  If so, use
	 * a shared helper (currently integrated into timeval-to-parts).
	 */

	/* Use the approach described in "Remarks" of FileTimeToLocalFileTime:
	 * http://msdn.microsoft.com/en-us/library/windows/desktop/ms724277(v=vs.85).aspx
	 */

	duk__set_systime_jan1970(&st1);
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st1, &tmp1);
	tmp2.QuadPart = (ULONGLONG) (d * 10000.0);  /* millisec -> 100ns units since jan 1, 1970 */
	tmp2.QuadPart += tmp1.QuadPart;             /* input 'd' in Windows UTC, 100ns units */

	ft1.dwLowDateTime = tmp2.LowPart;
	ft1.dwHighDateTime = tmp2.HighPart;
	if (FileTimeToSystemTime((const FILETIME *) &ft1, &st2) == 0) {
		DUK_D(DUK_DPRINT("FileTimeToSystemTime() failed, return tzoffset 0"));
		return 0;
	}
	if (SystemTimeToTzSpecificLocalTime((LPTIME_ZONE_INFORMATION) NULL, &st2, &st3) == 0) {
		DUK_D(DUK_DPRINT("SystemTimeToTzSpecificLocalTime() failed, return tzoffset 0"));
		return 0;
	}
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st3, &tmp3);

	/* Positive if local time ahead of UTC. */
	return (duk_int_t) (((LONGLONG) tmp3.QuadPart - (LONGLONG) tmp2.QuadPart) / DUK_I64_CONSTANT(10000000));  /* seconds */
}
#endif  /* DUK_USE_DATE_TZO_WINDOWS */

#if defined(DUK_USE_DATE_TZO_WINDOWS_NO_DST)
DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows_no_dst(duk_double_t d) {
	SYSTEMTIME st1;
	SYSTEMTIME st2;
	FILETIME ft1;
	FILETIME ft2;
	ULARGE_INTEGER tmp1;
	ULARGE_INTEGER tmp2;

	/* Do a similar computation to duk_bi_date_get_local_tzoffset_windows
	 * but without accounting for daylight savings time.  Use this on
	 * Windows platforms (like Durango) that don't support the
	 * SystemTimeToTzSpecificLocalTime() call.
	 */

	/* current time not needed for this computation */
	DUK_UNREF(d);

	duk__set_systime_jan1970(&st1);
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st1, &tmp1);

	ft1.dwLowDateTime = tmp1.LowPart;
	ft1.dwHighDateTime = tmp1.HighPart;
	if (FileTimeToLocalFileTime((const FILETIME *) &ft1, &ft2) == 0) {
		DUK_D(DUK_DPRINT("FileTimeToLocalFileTime() failed, return tzoffset 0"));
		return 0;
	}
	if (FileTimeToSystemTime((const FILETIME *) &ft2, &st2) == 0) {
		DUK_D(DUK_DPRINT("FileTimeToSystemTime() failed, return tzoffset 0"));
		return 0;
	}
	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st2, &tmp2);

	return (duk_int_t) (((LONGLONG) tmp2.QuadPart - (LONGLONG) tmp1.QuadPart) / DUK_I64_CONSTANT(10000000));  /* seconds */
}
#endif  /* DUK_USE_DATE_TZO_WINDOWS_NO_DST */

#if defined(DUK_USE_GET_MONOTONIC_TIME_WINDOWS_QPC)
DUK_INTERNAL duk_double_t duk_bi_date_get_monotonic_time_windows_qpc(void) {
	LARGE_INTEGER count, freq;

	/* There are legacy issues with QueryPerformanceCounter():
	 * - Potential jumps: https://support.microsoft.com/en-us/help/274323/performance-counter-value-may-unexpectedly-leap-forward
	 * - Differences between cores (XP): https://msdn.microsoft.com/en-us/library/windows/desktop/dn553408(v=vs.85).aspx#qpc_support_in_windows_versions
	 *
	 * We avoid these by enabling QPC by default only for Vista or later.
	 */

	if (QueryPerformanceCounter(&count) && QueryPerformanceFrequency(&freq)) {
		/* XXX: QueryPerformanceFrequency() can be cached */
		return (duk_double_t) count.QuadPart / (duk_double_t) freq.QuadPart * 1000.0;
	} else {
		/* MSDN: "On systems that run Windows XP or later, the function
		 * will always succeed and will thus never return zero."
		 * Provide minimal error path just in case user enables this
		 * feature in pre-XP Windows.
		 */
		return 0.0;
	}
}
#endif  /* DUK_USE_GET_MONOTONIC_TIME_WINDOWS_QPC */
/*
 *  Duktape built-ins
 *
 *  Size optimization note: it might seem that vararg multipurpose functions
 *  like fin(), enc(), and dec() are not very size optimal, but using a single
 *  user-visible ECMAScript function saves a lot of run-time footprint; each
 *  Function instance takes >100 bytes.  Using a shared native helper and a
 *  'magic' value won't save much if there are multiple Function instances
 *  anyway.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_DUKTAPE_BUILTIN)

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_info(duk_hthread *thr) {
	duk_inspect_value(thr, -1);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_act(duk_hthread *thr) {
	duk_int_t level;

	level = duk_to_int(thr, 0);
	duk_inspect_callstack_entry(thr, level);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_gc(duk_hthread *thr) {
	duk_small_uint_t flags;

	flags = (duk_small_uint_t) duk_get_uint(thr, 0);
	duk_heap_mark_and_sweep(thr->heap, flags);

	/* XXX: Not sure what the best return value would be in the API.
	 * Return true for now.
	 */
	duk_push_true(thr);
	return 1;
}

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_duktape_object_fin(duk_hthread *thr) {
	(void) duk_require_hobject(thr, 0);
	if (duk_get_top(thr) >= 2) {
		/* Set: currently a finalizer is disabled by setting it to
		 * undefined; this does not remove the property at the moment.
		 * The value could be type checked to be either a function
		 * or something else; if something else, the property could
		 * be deleted.  Must use duk_set_finalizer() to keep
		 * DUK_HOBJECT_FLAG_HAVE_FINALIZER in sync.
		 */
		duk_set_top(thr, 2);
		duk_set_finalizer(thr, 0);
		return 0;
	} else {
		/* Get. */
		DUK_ASSERT(duk_get_top(thr) == 1);
		duk_get_finalizer(thr, 0);
		return 1;
	}
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_enc(duk_hthread *thr) {
	duk_hstring *h_str;

	/* Vararg function: must be careful to check/require arguments.
	 * The JSON helpers accept invalid indices and treat them like
	 * non-existent optional parameters.
	 */

	h_str = duk_require_hstring(thr, 0);  /* Could reject symbols, but no point: won't match comparisons. */
	duk_require_valid_index(thr, 1);

	if (h_str == DUK_HTHREAD_STRING_HEX(thr)) {
		duk_set_top(thr, 2);
		duk_hex_encode(thr, 1);
		DUK_ASSERT_TOP(thr, 2);
	} else if (h_str == DUK_HTHREAD_STRING_BASE64(thr)) {
		duk_set_top(thr, 2);
		duk_base64_encode(thr, 1);
		DUK_ASSERT_TOP(thr, 2);
#if defined(DUK_USE_JSON_SUPPORT) && defined(DUK_USE_JX)
	} else if (h_str == DUK_HTHREAD_STRING_JX(thr)) {
		duk_bi_json_stringify_helper(thr,
		                             1 /*idx_value*/,
		                             2 /*idx_replacer*/,
		                             3 /*idx_space*/,
		                             DUK_JSON_FLAG_EXT_CUSTOM |
		                             DUK_JSON_FLAG_ASCII_ONLY |
		                             DUK_JSON_FLAG_AVOID_KEY_QUOTES /*flags*/);
#endif
#if defined(DUK_USE_JSON_SUPPORT) && defined(DUK_USE_JC)
	} else if (h_str == DUK_HTHREAD_STRING_JC(thr)) {
		duk_bi_json_stringify_helper(thr,
		                             1 /*idx_value*/,
		                             2 /*idx_replacer*/,
		                             3 /*idx_space*/,
		                             DUK_JSON_FLAG_EXT_COMPATIBLE |
		                             DUK_JSON_FLAG_ASCII_ONLY /*flags*/);
#endif
	} else {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_dec(duk_hthread *thr) {
	duk_hstring *h_str;

	/* Vararg function: must be careful to check/require arguments.
	 * The JSON helpers accept invalid indices and treat them like
	 * non-existent optional parameters.
	 */

	h_str = duk_require_hstring(thr, 0);  /* Could reject symbols, but no point: won't match comparisons */
	duk_require_valid_index(thr, 1);

	if (h_str == DUK_HTHREAD_STRING_HEX(thr)) {
		duk_set_top(thr, 2);
		duk_hex_decode(thr, 1);
		DUK_ASSERT_TOP(thr, 2);
	} else if (h_str == DUK_HTHREAD_STRING_BASE64(thr)) {
		duk_set_top(thr, 2);
		duk_base64_decode(thr, 1);
		DUK_ASSERT_TOP(thr, 2);
#if defined(DUK_USE_JSON_SUPPORT) && defined(DUK_USE_JX)
	} else if (h_str == DUK_HTHREAD_STRING_JX(thr)) {
		duk_bi_json_parse_helper(thr,
		                         1 /*idx_value*/,
		                         2 /*idx_replacer*/,
		                         DUK_JSON_FLAG_EXT_CUSTOM /*flags*/);
#endif
#if defined(DUK_USE_JSON_SUPPORT) && defined(DUK_USE_JC)
	} else if (h_str == DUK_HTHREAD_STRING_JC(thr)) {
		duk_bi_json_parse_helper(thr,
		                         1 /*idx_value*/,
		                         2 /*idx_replacer*/,
		                         DUK_JSON_FLAG_EXT_COMPATIBLE /*flags*/);
#endif
	} else {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}
	return 1;
}

/*
 *  Compact an object
 */

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_compact(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 1);
	duk_compact(thr, 0);
	return 1;  /* return the argument object */
}

#endif  /* DUK_USE_DUKTAPE_BUILTIN */
/*
 *  WHATWG Encoding API built-ins
 *
 *  API specification: https://encoding.spec.whatwg.org/#api
 *  Web IDL: https://www.w3.org/TR/WebIDL/
 */

/* #include duk_internal.h -> already included */

/*
 *  Data structures for encoding/decoding
 */

typedef struct {
	duk_uint8_t *out;      /* where to write next byte(s) */
	duk_codepoint_t lead;  /* lead surrogate */
} duk__encode_context;

typedef struct {
	/* UTF-8 decoding state */
	duk_codepoint_t codepoint;  /* built up incrementally */
	duk_uint8_t upper;          /* max value of next byte (decode error otherwise) */
	duk_uint8_t lower;          /* min value of next byte (ditto) */
	duk_uint8_t needed;         /* how many more bytes we need */
	duk_uint8_t bom_handled;    /* BOM seen or no longer expected */

	/* Decoder configuration */
	duk_uint8_t fatal;
	duk_uint8_t ignore_bom;
} duk__decode_context;

/* The signed duk_codepoint_t type is used to signal a decoded codepoint
 * (>= 0) or various other states using negative values.
 */
#define DUK__CP_CONTINUE   (-1)  /* continue to next byte, no completed codepoint */
#define DUK__CP_ERROR      (-2)  /* decoding error */
#define DUK__CP_RETRY      (-3)  /* decoding error; retry last byte */

/*
 *  Raw helpers for encoding/decoding
 */

/* Emit UTF-8 (= CESU-8) encoded U+FFFD (replacement char), i.e. ef bf bd. */
DUK_LOCAL duk_uint8_t *duk__utf8_emit_repl(duk_uint8_t *ptr) {
	*ptr++ = 0xef;
	*ptr++ = 0xbf;
	*ptr++ = 0xbd;
	return ptr;
}

DUK_LOCAL void duk__utf8_decode_init(duk__decode_context *dec_ctx) {
	/* (Re)init the decoding state of 'dec_ctx' but leave decoder
	 * configuration fields untouched.
	 */
	dec_ctx->codepoint = 0x0000L;
	dec_ctx->upper = 0xbf;
	dec_ctx->lower = 0x80;
	dec_ctx->needed = 0;
	dec_ctx->bom_handled = 0;
}

DUK_LOCAL duk_codepoint_t duk__utf8_decode_next(duk__decode_context *dec_ctx, duk_uint8_t x) {
	/*
	 *  UTF-8 algorithm based on the Encoding specification:
	 *  https://encoding.spec.whatwg.org/#utf-8-decoder
	 *
	 *  Two main states: decoding initial byte vs. decoding continuation
	 *  bytes.  Shortest length encoding is validated by restricting the
	 *  allowed range of first continuation byte using 'lower' and 'upper'.
	 */

	if (dec_ctx->needed == 0) {
		/* process initial byte */
		if (x <= 0x7f) {
			/* U+0000-U+007F, 1 byte (ASCII) */
			return (duk_codepoint_t) x;
		} else if (x >= 0xc2 && x <= 0xdf) {
			/* U+0080-U+07FF, 2 bytes */
			dec_ctx->needed = 1;
			dec_ctx->codepoint = x & 0x1f;
			DUK_ASSERT(dec_ctx->lower == 0x80);
			DUK_ASSERT(dec_ctx->upper == 0xbf);
			return DUK__CP_CONTINUE;
		} else if (x >= 0xe0 && x <= 0xef) {
			/* U+0800-U+FFFF, 3 bytes */
			if (x == 0xe0) {
				dec_ctx->lower = 0xa0;
				DUK_ASSERT(dec_ctx->upper == 0xbf);
			} else if (x == 0xed) {
				DUK_ASSERT(dec_ctx->lower == 0x80);
				dec_ctx->upper = 0x9f;
			}
			dec_ctx->needed = 2;
			dec_ctx->codepoint = x & 0x0f;
			return DUK__CP_CONTINUE;
		} else if (x >= 0xf0 && x <= 0xf4) {
			/* U+010000-U+10FFFF, 4 bytes */
			if (x == 0xf0) {
				dec_ctx->lower = 0x90;
				DUK_ASSERT(dec_ctx->upper == 0xbf);
			} else if (x == 0xf4) {
				DUK_ASSERT(dec_ctx->lower == 0x80);
				dec_ctx->upper = 0x8f;
			}
			dec_ctx->needed = 3;
			dec_ctx->codepoint = x & 0x07;
			return DUK__CP_CONTINUE;
		} else {
			/* not a legal initial byte */
			return DUK__CP_ERROR;
		}
	} else {
		/* process continuation byte */
		if (x >= dec_ctx->lower && x <= dec_ctx->upper) {
			dec_ctx->lower = 0x80;
			dec_ctx->upper = 0xbf;
			dec_ctx->codepoint = (dec_ctx->codepoint << 6) | (x & 0x3f);
			if (--dec_ctx->needed > 0) {
				/* need more bytes */
				return DUK__CP_CONTINUE;
			} else {
				/* got a codepoint */
				duk_codepoint_t ret;
				DUK_ASSERT(dec_ctx->codepoint <= 0x10ffffL);  /* Decoding rules guarantee. */
				ret = dec_ctx->codepoint;
				dec_ctx->codepoint = 0x0000L;
				dec_ctx->needed = 0;
				return ret;
			}
		} else {
			/* We just encountered an illegal UTF-8 continuation byte.  This might
			 * be the initial byte of the next character; if we return a plain
			 * error status and the decoder is in replacement mode, the character
			 * will be masked.  We still need to alert the caller to the error
			 * though.
			 */
			dec_ctx->codepoint = 0x0000L;
			dec_ctx->needed = 0;
			dec_ctx->lower = 0x80;
			dec_ctx->upper = 0xbf;
			return DUK__CP_RETRY;
		}
	}
}

#if defined(DUK_USE_ENCODING_BUILTINS)
DUK_LOCAL void duk__utf8_encode_char(void *udata, duk_codepoint_t codepoint) {
	duk__encode_context *enc_ctx;

	DUK_ASSERT(codepoint >= 0);
	enc_ctx = (duk__encode_context *) udata;
	DUK_ASSERT(enc_ctx != NULL);

#if !defined(DUK_USE_PREFER_SIZE)
	if (codepoint <= 0x7f && enc_ctx->lead == 0x0000L) {
		/* Fast path for ASCII. */
		*enc_ctx->out++ = (duk_uint8_t) codepoint;
		return;
	}
#endif

	if (DUK_UNLIKELY(codepoint > 0x10ffffL)) {
		/* cannot legally encode in UTF-8 */
		codepoint = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
	} else if (codepoint >= 0xd800L && codepoint <= 0xdfffL) {
		if (codepoint <= 0xdbffL) {
			/* high surrogate */
			duk_codepoint_t prev_lead = enc_ctx->lead;
			enc_ctx->lead = codepoint;
			if (prev_lead == 0x0000L) {
				/* high surrogate, no output */
				return;
			} else {
				/* consecutive high surrogates, consider first one unpaired */
				codepoint = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
			}
		} else {
			/* low surrogate */
			if (enc_ctx->lead != 0x0000L) {
				codepoint = (duk_codepoint_t) (0x010000L + ((enc_ctx->lead - 0xd800L) << 10) + (codepoint - 0xdc00L));
				enc_ctx->lead = 0x0000L;
			} else {
				/* unpaired low surrogate */
				DUK_ASSERT(enc_ctx->lead == 0x0000L);
				codepoint = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
			}
		}
	} else {
		if (enc_ctx->lead != 0x0000L) {
			/* unpaired high surrogate: emit replacement character and the input codepoint */
			enc_ctx->lead = 0x0000L;
			enc_ctx->out = duk__utf8_emit_repl(enc_ctx->out);
		}
	}

	/* Codepoint may be original input, a decoded surrogate pair, or may
	 * have been replaced with U+FFFD.
	 */
	enc_ctx->out += duk_unicode_encode_xutf8((duk_ucodepoint_t) codepoint, enc_ctx->out);
}
#endif  /* DUK_USE_ENCODING_BUILTINS */

/* Shared helper for buffer-to-string using a TextDecoder() compatible UTF-8
 * decoder.
 */
DUK_LOCAL duk_ret_t duk__decode_helper(duk_hthread *thr, duk__decode_context *dec_ctx) {
	const duk_uint8_t *input;
	duk_size_t len = 0;
	duk_size_t len_tmp;
	duk_bool_t stream = 0;
	duk_codepoint_t codepoint;
	duk_uint8_t *output;
	const duk_uint8_t *in;
	duk_uint8_t *out;

	DUK_ASSERT(dec_ctx != NULL);

	/* Careful with input buffer pointer: any side effects involving
	 * code execution (e.g. getters, coercion calls, and finalizers)
	 * may cause a resize and invalidate a pointer we've read.  This
	 * is why the pointer is actually looked up at the last minute.
	 * Argument validation must still happen first to match WHATWG
	 * required side effect order.
	 */

	if (duk_is_undefined(thr, 0)) {
		duk_push_fixed_buffer_nozero(thr, 0);
		duk_replace(thr, 0);
	}
	(void) duk_require_buffer_data(thr, 0, &len);  /* Need 'len', avoid pointer. */

	if (duk_check_type_mask(thr, 1, DUK_TYPE_MASK_UNDEFINED |
	                                DUK_TYPE_MASK_NULL |
	                                DUK_TYPE_MASK_NONE)) {
		/* Use defaults, treat missing value like undefined. */
	} else {
		duk_require_type_mask(thr, 1, DUK_TYPE_MASK_UNDEFINED |
	                                      DUK_TYPE_MASK_NULL |
	                                      DUK_TYPE_MASK_LIGHTFUNC |
	                                      DUK_TYPE_MASK_BUFFER |
		                              DUK_TYPE_MASK_OBJECT);
		if (duk_get_prop_literal(thr, 1, "stream")) {
			stream = duk_to_boolean(thr, -1);
		}
	}

	/* Allowance is 3*len in the general case because all bytes may potentially
	 * become U+FFFD.  If the first byte completes a non-BMP codepoint it will
	 * decode to a CESU-8 surrogate pair (6 bytes) so we allow 3 extra bytes to
	 * compensate: (1*3)+3 = 6.  Non-BMP codepoints are safe otherwise because
	 * the 4->6 expansion is well under the 3x allowance.
	 *
	 * XXX: As with TextEncoder, need a better buffer allocation strategy here.
	 */
	if (len >= (DUK_HBUFFER_MAX_BYTELEN / 3) - 3) {
		DUK_ERROR_TYPE(thr, DUK_STR_RESULT_TOO_LONG);
		DUK_WO_NORETURN(return 0;);
	}
	output = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, 3 + (3 * len));  /* used parts will be always manually written over */

	input = (const duk_uint8_t *) duk_get_buffer_data(thr, 0, &len_tmp);
	DUK_ASSERT(input != NULL || len == 0);
	if (DUK_UNLIKELY(len != len_tmp)) {
		/* Very unlikely but possible: source buffer was resized by
		 * a side effect when fixed buffer was pushed.  Output buffer
		 * may not be large enough to hold output, so just fail if
		 * length has changed.
		 */
		DUK_D(DUK_DPRINT("input buffer resized by side effect, fail"));
		goto fail_type;
	}

	/* From this point onwards it's critical that no side effect occur
	 * which may disturb 'input': finalizer execution, property accesses,
	 * active coercions, etc.  Even an allocation related mark-and-sweep
	 * may affect the pointer because it may trigger a pending finalizer.
	 */

	in = input;
	out = output;
	while (in < input + len) {
		codepoint = duk__utf8_decode_next(dec_ctx, *in++);
		if (codepoint < 0) {
			if (codepoint == DUK__CP_CONTINUE) {
				continue;
			}

			/* Decoding error with or without retry. */
			DUK_ASSERT(codepoint == DUK__CP_ERROR || codepoint == DUK__CP_RETRY);
			if (codepoint == DUK__CP_RETRY) {
				--in;  /* retry last byte */
			}
			/* replacement mode: replace with U+FFFD */
			codepoint = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
			if (dec_ctx->fatal) {
				/* fatal mode: throw a TypeError */
				goto fail_type;
			}
			/* Continue with 'codepoint', Unicode replacement. */
		}
		DUK_ASSERT(codepoint >= 0x0000L && codepoint <= 0x10ffffL);

		if (!dec_ctx->bom_handled) {
			dec_ctx->bom_handled = 1;
			if (codepoint == 0xfeffL && !dec_ctx->ignore_bom) {
				continue;
			}
		}

		out += duk_unicode_encode_cesu8((duk_ucodepoint_t) codepoint, out);
		DUK_ASSERT(out <= output + (3 + (3 * len)));
	}

	if (!stream) {
		if (dec_ctx->needed != 0) {
			/* truncated sequence at end of buffer */
			if (dec_ctx->fatal) {
				goto fail_type;
			} else {
				out += duk_unicode_encode_cesu8(DUK_UNICODE_CP_REPLACEMENT_CHARACTER, out);
				DUK_ASSERT(out <= output + (3 + (3 * len)));
			}
		}
		duk__utf8_decode_init(dec_ctx);  /* Initialize decoding state for potential reuse. */
	}

	/* Output buffer is fixed and thus stable even if there had been
	 * side effects (which there shouldn't be).
	 */
	duk_push_lstring(thr, (const char *) output, (duk_size_t) (out - output));
	return 1;

 fail_type:
	DUK_ERROR_TYPE(thr, DUK_STR_UTF8_DECODE_FAILED);
	DUK_WO_NORETURN(return 0;);
}

/*
 *  Built-in bindings
 */

#if defined(DUK_USE_ENCODING_BUILTINS)
DUK_INTERNAL duk_ret_t duk_bi_textencoder_constructor(duk_hthread *thr) {
	/* TextEncoder currently requires no persistent state, so the constructor
	 * does nothing on purpose.
	 */

	duk_require_constructor_call(thr);
	return 0;
}

DUK_INTERNAL duk_ret_t duk_bi_textencoder_prototype_encoding_getter(duk_hthread *thr) {
	duk_push_literal(thr, "utf-8");
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_textencoder_prototype_encode(duk_hthread *thr) {
	duk__encode_context enc_ctx;
	duk_size_t len;
	duk_size_t final_len;
	duk_uint8_t *output;

	DUK_ASSERT_TOP(thr, 1);
	if (duk_is_undefined(thr, 0)) {
		len = 0;
	} else {
		duk_hstring *h_input;

		h_input = duk_to_hstring(thr, 0);
		DUK_ASSERT(h_input != NULL);

		len = (duk_size_t) DUK_HSTRING_GET_CHARLEN(h_input);
		if (len >= DUK_HBUFFER_MAX_BYTELEN / 3) {
			DUK_ERROR_TYPE(thr, DUK_STR_RESULT_TOO_LONG);
			DUK_WO_NORETURN(return 0;);
		}
	}

	/* Allowance is 3*len because all bytes can potentially be replaced with
	 * U+FFFD -- which rather inconveniently encodes to 3 bytes in UTF-8.
	 * Rely on dynamic buffer data pointer stability: no other code has
	 * access to the data pointer.
	 *
	 * XXX: The buffer allocation strategy used here is rather inefficient.
	 * Maybe switch to a chunk-based strategy, or preprocess the string to
	 * figure out the space needed ahead of time?
	 */
	DUK_ASSERT(3 * len >= len);
	output = (duk_uint8_t *) duk_push_dynamic_buffer(thr, 3 * len);

	if (len > 0) {
		DUK_ASSERT(duk_is_string(thr, 0));  /* True if len > 0. */

		/* XXX: duk_decode_string() is used to process the input
		 * string.  For standard ECMAScript strings, represented
		 * internally as CESU-8, this is fine.  However, behavior
		 * beyond CESU-8 is not very strict: codepoints using an
		 * extended form of UTF-8 are also accepted, and invalid
		 * codepoint sequences (which are allowed in Duktape strings)
		 * are not handled as well as they could (e.g. invalid
		 * continuation bytes may mask following codepoints).
		 * This is how ECMAScript code would also see such strings.
		 * Maybe replace duk_decode_string() with an explicit strict
		 * CESU-8 decoder here?
		 */
		enc_ctx.lead = 0x0000L;
		enc_ctx.out = output;
		duk_decode_string(thr, 0, duk__utf8_encode_char, (void *) &enc_ctx);
		if (enc_ctx.lead != 0x0000L) {
			/* unpaired high surrogate at end of string */
			enc_ctx.out = duk__utf8_emit_repl(enc_ctx.out);
			DUK_ASSERT(enc_ctx.out <= output + (3 * len));
		}

		/* The output buffer is usually very much oversized, so shrink it to
		 * actually needed size.  Pointer stability assumed up to this point.
		 */
		DUK_ASSERT_TOP(thr, 2);
		DUK_ASSERT(output == (duk_uint8_t *) duk_get_buffer_data(thr, -1, NULL));

		final_len = (duk_size_t) (enc_ctx.out - output);
		duk_resize_buffer(thr, -1, final_len);
		/* 'output' and 'enc_ctx.out' are potentially invalidated by the resize. */
	} else {
		final_len = 0;
	}

	/* Standard WHATWG output is a Uint8Array.  Here the Uint8Array will
	 * be backed by a dynamic buffer which differs from e.g. Uint8Arrays
	 * created as 'new Uint8Array(N)'.  ECMAScript code won't see the
	 * difference but C code will.  When bufferobjects are not supported,
	 * returns a plain dynamic buffer.
	 */
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	duk_push_buffer_object(thr, -1, 0, final_len, DUK_BUFOBJ_UINT8ARRAY);
#endif
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_textdecoder_constructor(duk_hthread *thr) {
	duk__decode_context *dec_ctx;
	duk_bool_t fatal = 0;
	duk_bool_t ignore_bom = 0;

	DUK_ASSERT_TOP(thr, 2);
	duk_require_constructor_call(thr);
	if (!duk_is_undefined(thr, 0)) {
		/* XXX: For now ignore 'label' (encoding identifier). */
		duk_to_string(thr, 0);
	}
	if (!duk_is_null_or_undefined(thr, 1)) {
		if (duk_get_prop_literal(thr, 1, "fatal")) {
			fatal = duk_to_boolean(thr, -1);
		}
		if (duk_get_prop_literal(thr, 1, "ignoreBOM")) {
			ignore_bom = duk_to_boolean(thr, -1);
		}
	}

	duk_push_this(thr);

	/* The decode context is not assumed to be zeroed; all fields are
	 * initialized explicitly.
	 */
	dec_ctx = (duk__decode_context *) duk_push_fixed_buffer(thr, sizeof(duk__decode_context));
	dec_ctx->fatal = (duk_uint8_t) fatal;
	dec_ctx->ignore_bom = (duk_uint8_t) ignore_bom;
	duk__utf8_decode_init(dec_ctx);  /* Initializes remaining fields. */

	duk_put_prop_literal(thr, -2, DUK_INTERNAL_SYMBOL("Context"));
	return 0;
}

/* Get TextDecoder context from 'this'; leaves garbage on stack. */
DUK_LOCAL duk__decode_context *duk__get_textdecoder_context(duk_hthread *thr) {
	duk__decode_context *dec_ctx;
	duk_push_this(thr);
	duk_get_prop_literal(thr, -1, DUK_INTERNAL_SYMBOL("Context"));
	dec_ctx = (duk__decode_context *) duk_require_buffer(thr, -1, NULL);
	DUK_ASSERT(dec_ctx != NULL);
	return dec_ctx;
}

DUK_INTERNAL duk_ret_t duk_bi_textdecoder_prototype_shared_getter(duk_hthread *thr) {
	duk__decode_context *dec_ctx;
	duk_int_t magic;

	dec_ctx = duk__get_textdecoder_context(thr);
	magic = duk_get_current_magic(thr);
	switch (magic) {
	case 0:
		/* Encoding is now fixed, so _Context lookup is only needed to
		 * validate the 'this' binding (TypeError if not TextDecoder-like).
		 */
		duk_push_literal(thr, "utf-8");
		break;
	case 1:
		duk_push_boolean(thr, dec_ctx->fatal);
		break;
	default:
		duk_push_boolean(thr, dec_ctx->ignore_bom);
		break;
	}

	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_textdecoder_prototype_decode(duk_hthread *thr) {
	duk__decode_context *dec_ctx;

	dec_ctx = duk__get_textdecoder_context(thr);
	return duk__decode_helper(thr, dec_ctx);
}
#endif  /* DUK_USE_ENCODING_BUILTINS */

/*
 *  Internal helper for Node.js Buffer
 */

/* Internal helper used for Node.js Buffer .toString().  Value stack convention
 * is currently odd: it mimics TextDecoder .decode() so that argument must be at
 * index 0, and decode options (not present for Buffer) at index 1.  Return value
 * is a Duktape/C function return value.
 */
DUK_INTERNAL duk_ret_t duk_textdecoder_decode_utf8_nodejs(duk_hthread *thr) {
	duk__decode_context dec_ctx;

	dec_ctx.fatal = 0;  /* use replacement chars */
	dec_ctx.ignore_bom = 1;  /* ignore BOMs (matches Node.js Buffer .toString()) */
	duk__utf8_decode_init(&dec_ctx);

	return duk__decode_helper(thr, &dec_ctx);
}

/* automatic undefs */
#undef DUK__CP_CONTINUE
#undef DUK__CP_ERROR
#undef DUK__CP_RETRY
/*
 *  Error built-ins
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL duk_ret_t duk_bi_error_constructor_shared(duk_hthread *thr) {
	/* Behavior for constructor and non-constructor call is
	 * the same except for augmenting the created error.  When
	 * called as a constructor, the caller (duk_new()) will handle
	 * augmentation; when called as normal function, we need to do
	 * it here.
	 */

	duk_small_int_t bidx_prototype = duk_get_current_magic(thr);

	/* same for both error and each subclass like TypeError */
	duk_uint_t flags_and_class = DUK_HOBJECT_FLAG_EXTENSIBLE |
	                             DUK_HOBJECT_FLAG_FASTREFS |
	                             DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ERROR);

	(void) duk_push_object_helper(thr, flags_and_class, bidx_prototype);

	/* If message is undefined, the own property 'message' is not set at
	 * all to save property space.  An empty message is inherited anyway.
	 */
	if (!duk_is_undefined(thr, 0)) {
		duk_to_string(thr, 0);
		duk_dup_0(thr);  /* [ message error message ] */
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE, DUK_PROPDESC_FLAGS_WC);
	}

	/* Augment the error if called as a normal function.  __FILE__ and __LINE__
	 * are not desirable in this case.
	 */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
	if (!duk_is_constructor_call(thr)) {
		duk_err_augment_error_create(thr, thr, NULL, 0, DUK_AUGMENT_FLAG_NOBLAME_FILELINE);
	}
#endif

	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_to_string(duk_hthread *thr) {
	/* XXX: optimize with more direct internal access */

	duk_push_this(thr);
	(void) duk_require_hobject_promote_mask(thr, -1, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);

	/* [ ... this ] */

	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_NAME);
	if (duk_is_undefined(thr, -1)) {
		duk_pop(thr);
		duk_push_literal(thr, "Error");
	} else {
		duk_to_string(thr, -1);
	}

	/* [ ... this name ] */

	/* XXX: Are steps 6 and 7 in E5 Section 15.11.4.4 duplicated by
	 * accident or are they actually needed?  The first ToString()
	 * could conceivably return 'undefined'.
	 */
	duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE);
	if (duk_is_undefined(thr, -1)) {
		duk_pop(thr);
		duk_push_hstring_empty(thr);
	} else {
		duk_to_string(thr, -1);
	}

	/* [ ... this name message ] */

	if (duk_get_length(thr, -2) == 0) {
		/* name is empty -> return message */
		return 1;
	}
	if (duk_get_length(thr, -1) == 0) {
		/* message is empty -> return name */
		duk_pop(thr);
		return 1;
	}
	duk_push_literal(thr, ": ");
	duk_insert(thr, -2);  /* ... name ': ' message */
	duk_concat(thr, 3);

	return 1;
}

#if defined(DUK_USE_TRACEBACKS)

/*
 *  Traceback handling
 *
 *  The unified helper decodes the traceback and produces various requested
 *  outputs.  It should be optimized for size, and may leave garbage on stack,
 *  only the topmost return value matters.  For instance, traceback separator
 *  and decoded strings are pushed even when looking for filename only.
 *
 *  NOTE: although _Tracedata is an internal property, user code can currently
 *  write to the array (or replace it with something other than an array).
 *  The code below must tolerate arbitrary _Tracedata.  It can throw errors
 *  etc, but cannot cause a segfault or memory unsafe behavior.
 */

/* constants arbitrary, chosen for small loads */
#define DUK__OUTPUT_TYPE_TRACEBACK   (-1)
#define DUK__OUTPUT_TYPE_FILENAME    0
#define DUK__OUTPUT_TYPE_LINENUMBER  1

DUK_LOCAL duk_ret_t duk__error_getter_helper(duk_hthread *thr, duk_small_int_t output_type) {
	duk_idx_t idx_td;
	duk_small_int_t i;  /* traceback depth fits into 16 bits */
	duk_small_int_t t;  /* stack type fits into 16 bits */
	duk_small_int_t count_func = 0;  /* traceback depth ensures fits into 16 bits */
	const char *str_tailcall = " tailcall";
	const char *str_strict = " strict";
	const char *str_construct = " construct";
	const char *str_prevyield = " preventsyield";
	const char *str_directeval = " directeval";
	const char *str_empty = "";

	DUK_ASSERT_TOP(thr, 0);  /* fixed arg count */

	duk_push_this(thr);
	duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_TRACEDATA);
	idx_td = duk_get_top_index(thr);

	duk_push_hstring_stridx(thr, DUK_STRIDX_NEWLINE_4SPACE);
	duk_push_this(thr);

	/* [ ... this tracedata sep this ] */

	/* XXX: skip null filename? */

	if (duk_check_type(thr, idx_td, DUK_TYPE_OBJECT)) {
		/* Current tracedata contains 2 entries per callstack entry. */
		for (i = 0; ; i += 2) {
			duk_int_t pc;
			duk_uint_t line;
			duk_uint_t flags;
			duk_double_t d;
			const char *funcname;
			const char *filename;
			duk_hobject *h_func;
			duk_hstring *h_name;

			duk_require_stack(thr, 5);
			duk_get_prop_index(thr, idx_td, (duk_uarridx_t) i);
			duk_get_prop_index(thr, idx_td, (duk_uarridx_t) (i + 1));
			d = duk_to_number_m1(thr);
			pc = duk_double_to_int_t(DUK_FMOD(d, DUK_DOUBLE_2TO32));
			flags = duk_double_to_uint_t(DUK_FLOOR(d / DUK_DOUBLE_2TO32));
			t = (duk_small_int_t) duk_get_type(thr, -2);

			if (t == DUK_TYPE_OBJECT || t == DUK_TYPE_LIGHTFUNC) {
				/*
				 *  ECMAScript/native function call or lightfunc call
				 */

				count_func++;

				/* [ ... v1(func) v2(pc+flags) ] */

				/* These may be systematically omitted by Duktape
				 * with certain config options, but allow user to
				 * set them on a case-by-case basis.
				 */
				duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_NAME);
				duk_get_prop_stridx_short(thr, -3, DUK_STRIDX_FILE_NAME);

#if defined(DUK_USE_PC2LINE)
				line = (duk_uint_t) duk_hobject_pc2line_query(thr, -4, (duk_uint_fast32_t) pc);
#else
				line = 0;
#endif

				/* [ ... v1 v2 name filename ] */

				/* When looking for .fileName/.lineNumber, blame first
				 * function which has a .fileName.
				 */
				if (duk_is_string_notsymbol(thr, -1)) {
					if (output_type == DUK__OUTPUT_TYPE_FILENAME) {
						return 1;
					} else if (output_type == DUK__OUTPUT_TYPE_LINENUMBER) {
						duk_push_uint(thr, line);
						return 1;
					}
				}

				/* XXX: Change 'anon' handling here too, to use empty string for anonymous functions? */
				/* XXX: Could be improved by coercing to a readable duk_tval (especially string escaping) */
				h_name = duk_get_hstring_notsymbol(thr, -2);  /* may be NULL */
				funcname = (h_name == NULL || h_name == DUK_HTHREAD_STRING_EMPTY_STRING(thr)) ?
				           "[anon]" : (const char *) DUK_HSTRING_GET_DATA(h_name);
				filename = duk_get_string_notsymbol(thr, -1);
				filename = filename ? filename : "";
				DUK_ASSERT(funcname != NULL);
				DUK_ASSERT(filename != NULL);

				h_func = duk_get_hobject(thr, -4);  /* NULL for lightfunc */

				if (h_func == NULL) {
					duk_push_sprintf(thr, "at %s light%s%s%s%s%s",
					                 (const char *) funcname,
					                 (const char *) ((flags & DUK_ACT_FLAG_STRICT) ? str_strict : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_TAILCALLED) ? str_tailcall : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_CONSTRUCT) ? str_construct : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_DIRECT_EVAL) ? str_directeval : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_PREVENT_YIELD) ? str_prevyield : str_empty));
				} else if (DUK_HOBJECT_HAS_NATFUNC(h_func)) {
					duk_push_sprintf(thr, "at %s (%s) native%s%s%s%s%s",
					                 (const char *) funcname,
					                 (const char *) filename,
					                 (const char *) ((flags & DUK_ACT_FLAG_STRICT) ? str_strict : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_TAILCALLED) ? str_tailcall : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_CONSTRUCT) ? str_construct : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_DIRECT_EVAL) ? str_directeval : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_PREVENT_YIELD) ? str_prevyield : str_empty));
				} else {
					duk_push_sprintf(thr, "at %s (%s:%lu)%s%s%s%s%s",
					                 (const char *) funcname,
					                 (const char *) filename,
					                 (unsigned long) line,
					                 (const char *) ((flags & DUK_ACT_FLAG_STRICT) ? str_strict : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_TAILCALLED) ? str_tailcall : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_CONSTRUCT) ? str_construct : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_DIRECT_EVAL) ? str_directeval : str_empty),
					                 (const char *) ((flags & DUK_ACT_FLAG_PREVENT_YIELD) ? str_prevyield : str_empty));
				}
				duk_replace(thr, -5);   /* [ ... v1 v2 name filename str ] -> [ ... str v2 name filename ] */
				duk_pop_3(thr);         /* -> [ ... str ] */
			} else if (t == DUK_TYPE_STRING) {
				const char *str_file;

				/*
				 *  __FILE__ / __LINE__ entry, here 'pc' is line number directly.
				 *  Sometimes __FILE__ / __LINE__ is reported as the source for
				 *  the error (fileName, lineNumber), sometimes not.
				 */

				/* [ ... v1(filename) v2(line+flags) ] */

				/* When looking for .fileName/.lineNumber, blame compilation
				 * or C call site unless flagged not to do so.
				 */
				if (!(flags & DUK_TB_FLAG_NOBLAME_FILELINE)) {
					if (output_type == DUK__OUTPUT_TYPE_FILENAME) {
						duk_pop(thr);
						return 1;
					} else if (output_type == DUK__OUTPUT_TYPE_LINENUMBER) {
						duk_push_int(thr, pc);
						return 1;
					}
				}

				/* Tracedata is trusted but avoid any risk of using a NULL
				 * for %s format because it has undefined behavior.  Symbols
				 * don't need to be explicitly rejected as they pose no memory
				 * safety issues.
				 */
				str_file = (const char *) duk_get_string(thr, -2);
				duk_push_sprintf(thr, "at [anon] (%s:%ld) internal",
				                 (const char *) (str_file ? str_file : "null"), (long) pc);
				duk_replace(thr, -3);  /* [ ... v1 v2 str ] -> [ ... str v2 ] */
				duk_pop(thr);          /* -> [ ... str ] */
			} else {
				/* unknown, ignore */
				duk_pop_2(thr);
				break;
			}
		}

		if (count_func >= DUK_USE_TRACEBACK_DEPTH) {
			/* Possibly truncated; there is no explicit truncation
			 * marker so this is the best we can do.
			 */

			duk_push_hstring_stridx(thr, DUK_STRIDX_BRACKETED_ELLIPSIS);
		}
	}

	/* [ ... this tracedata sep this str1 ... strN ] */

	if (output_type != DUK__OUTPUT_TYPE_TRACEBACK) {
		return 0;
	} else {
		/* The 'this' after 'sep' will get ToString() coerced by
		 * duk_join() automatically.  We don't want to do that
		 * coercion when providing .fileName or .lineNumber (GH-254).
		 */
		duk_join(thr, duk_get_top(thr) - (idx_td + 2) /*count, not including sep*/);
		return 1;
	}
}

/* XXX: Output type could be encoded into native function 'magic' value to
 * save space.  For setters the stridx could be encoded into 'magic'.
 */

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_stack_getter(duk_hthread *thr) {
	return duk__error_getter_helper(thr, DUK__OUTPUT_TYPE_TRACEBACK);
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_filename_getter(duk_hthread *thr) {
	return duk__error_getter_helper(thr, DUK__OUTPUT_TYPE_FILENAME);
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_linenumber_getter(duk_hthread *thr) {
	return duk__error_getter_helper(thr, DUK__OUTPUT_TYPE_LINENUMBER);
}

#else  /* DUK_USE_TRACEBACKS */

/*
 *  Traceback handling when tracebacks disabled.
 *
 *  The fileName / lineNumber stubs are now necessary because built-in
 *  data will include the accessor properties in Error.prototype.  If those
 *  are removed for builds without tracebacks, these can also be removed.
 *  'stack' should still be present and produce a ToString() equivalent:
 *  this is useful for user code which prints a stacktrace and expects to
 *  see something useful.  A normal stacktrace also begins with a ToString()
 *  of the error so this makes sense.
 */

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_stack_getter(duk_hthread *thr) {
	/* XXX: remove this native function and map 'stack' accessor
	 * to the toString() implementation directly.
	 */
	return duk_bi_error_prototype_to_string(thr);
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_filename_getter(duk_hthread *thr) {
	DUK_UNREF(thr);
	return 0;
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_linenumber_getter(duk_hthread *thr) {
	DUK_UNREF(thr);
	return 0;
}

#endif  /* DUK_USE_TRACEBACKS */

DUK_LOCAL duk_ret_t duk__error_setter_helper(duk_hthread *thr, duk_small_uint_t stridx_key) {
	/* Attempt to write 'stack', 'fileName', 'lineNumber' works as if
	 * user code called Object.defineProperty() to create an overriding
	 * own property.  This allows user code to overwrite .fileName etc
	 * intuitively as e.g. "err.fileName = 'dummy'" as one might expect.
	 * See https://github.com/svaarala/duktape/issues/387.
	 */

	DUK_ASSERT_TOP(thr, 1);  /* fixed arg count: value */

	duk_push_this(thr);
	duk_push_hstring_stridx(thr, stridx_key);
	duk_dup_0(thr);

	/* [ ... obj key value ] */

	DUK_DD(DUK_DDPRINT("error setter: %!T %!T %!T",
	                   duk_get_tval(thr, -3), duk_get_tval(thr, -2), duk_get_tval(thr, -1)));

	duk_def_prop(thr, -3, DUK_DEFPROP_HAVE_VALUE |
	                      DUK_DEFPROP_HAVE_WRITABLE | DUK_DEFPROP_WRITABLE |
	                      DUK_DEFPROP_HAVE_ENUMERABLE | /*not enumerable*/
	                      DUK_DEFPROP_HAVE_CONFIGURABLE | DUK_DEFPROP_CONFIGURABLE);
	return 0;
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_stack_setter(duk_hthread *thr) {
	return duk__error_setter_helper(thr, DUK_STRIDX_STACK);
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_filename_setter(duk_hthread *thr) {
	return duk__error_setter_helper(thr, DUK_STRIDX_FILE_NAME);
}

DUK_INTERNAL duk_ret_t duk_bi_error_prototype_linenumber_setter(duk_hthread *thr) {
	return duk__error_setter_helper(thr, DUK_STRIDX_LINE_NUMBER);
}

/* automatic undefs */
#undef DUK__OUTPUT_TYPE_FILENAME
#undef DUK__OUTPUT_TYPE_LINENUMBER
#undef DUK__OUTPUT_TYPE_TRACEBACK
/*
 *  Function built-ins
 */

/* #include duk_internal.h -> already included */

/* Needed even when Function built-in is disabled. */
DUK_INTERNAL duk_ret_t duk_bi_function_prototype(duk_hthread *thr) {
	/* ignore arguments, return undefined (E5 Section 15.3.4) */
	DUK_UNREF(thr);
	return 0;
}

#if defined(DUK_USE_FUNCTION_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_function_constructor(duk_hthread *thr) {
	duk_hstring *h_sourcecode;
	duk_idx_t nargs;
	duk_idx_t i;
	duk_small_uint_t comp_flags;
	duk_hcompfunc *func;
	duk_hobject *outer_lex_env;
	duk_hobject *outer_var_env;

	/* normal and constructor calls have identical semantics */

	nargs = duk_get_top(thr);
	for (i = 0; i < nargs; i++) {
		duk_to_string(thr, i);  /* Rejects Symbols during coercion. */
	}

	if (nargs == 0) {
		duk_push_hstring_empty(thr);
		duk_push_hstring_empty(thr);
	} else if (nargs == 1) {
		/* XXX: cover this with the generic >1 case? */
		duk_push_hstring_empty(thr);
	} else {
		duk_insert(thr, 0);   /* [ arg1 ... argN-1 body] -> [body arg1 ... argN-1] */
		duk_push_literal(thr, ",");
		duk_insert(thr, 1);
		duk_join(thr, nargs - 1);
	}

	/* [ body formals ], formals is comma separated list that needs to be parsed */

	DUK_ASSERT_TOP(thr, 2);

	/* XXX: this placeholder is not always correct, but use for now.
	 * It will fail in corner cases; see test-dev-func-cons-args.js.
	 */
	duk_push_literal(thr, "function(");
	duk_dup_1(thr);
	duk_push_literal(thr, "){");
	duk_dup_0(thr);
	duk_push_literal(thr, "\n}");  /* Newline is important to handle trailing // comment. */
	duk_concat(thr, 5);

	/* [ body formals source ] */

	DUK_ASSERT_TOP(thr, 3);

	/* strictness is not inherited, intentional */
	comp_flags = DUK_COMPILE_FUNCEXPR;

	duk_push_hstring_stridx(thr, DUK_STRIDX_COMPILE);  /* XXX: copy from caller? */  /* XXX: ignored now */
	h_sourcecode = duk_require_hstring(thr, -2);  /* no symbol check needed; -2 is concat'd code */
	duk_js_compile(thr,
	               (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_sourcecode),
	               (duk_size_t) DUK_HSTRING_GET_BYTELEN(h_sourcecode),
	               comp_flags);

	/* Force .name to 'anonymous' (ES2015). */
	duk_push_literal(thr, "anonymous");
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);

	func = (duk_hcompfunc *) duk_known_hobject(thr, -1);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) func));
	DUK_ASSERT(DUK_HOBJECT_HAS_CONSTRUCTABLE((duk_hobject *) func));

	/* [ body formals source template ] */

	/* only outer_lex_env matters, as functions always get a new
	 * variable declaration environment.
	 */

	outer_lex_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
	outer_var_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];

	duk_js_push_closure(thr, func, outer_var_env, outer_lex_env, 1 /*add_auto_proto*/);

	/* [ body formals source template closure ] */

	return 1;
}
#endif  /* DUK_USE_FUNCTION_BUILTIN */

#if defined(DUK_USE_FUNCTION_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_to_string(duk_hthread *thr) {
	duk_tval *tv;

	/*
	 *  E5 Section 15.3.4.2 places few requirements on the output of
	 *  this function: the result is implementation dependent, must
	 *  follow FunctionDeclaration syntax (in particular, must have a
	 *  name even for anonymous functions or functions with empty name).
	 *  The output does NOT need to compile into anything useful.
	 *
	 *  E6 Section 19.2.3.5 changes the requirements completely: the
	 *  result must either eval() to a functionally equivalent object
	 *  OR eval() to a SyntaxError.
	 *
	 *  We opt for the SyntaxError approach for now, with a syntax that
	 *  mimics V8's native function syntax:
	 *
	 *      'function cos() { [native code] }'
	 *
	 *  but extended with [ecmascript code], [bound code], and
	 *  [lightfunc code].
	 */

	duk_push_this(thr);
	tv = DUK_GET_TVAL_NEGIDX(thr, -1);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv);
		const char *func_name;

		/* Function name: missing/undefined is mapped to empty string,
		 * otherwise coerce to string.  No handling for invalid identifier
		 * characters or e.g. '{' in the function name.  This doesn't
		 * really matter as long as a SyntaxError results.  Technically
		 * if the name contained a suitable prefix followed by '//' it
		 * might cause the result to parse without error.
		 */
		duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_NAME);
		if (duk_is_undefined(thr, -1)) {
			func_name = "";
		} else {
			func_name = duk_to_string(thr, -1);
			DUK_ASSERT(func_name != NULL);
		}

		if (DUK_HOBJECT_IS_COMPFUNC(obj)) {
			duk_push_sprintf(thr, "function %s() { [ecmascript code] }", (const char *) func_name);
		} else if (DUK_HOBJECT_IS_NATFUNC(obj)) {
			duk_push_sprintf(thr, "function %s() { [native code] }", (const char *) func_name);
		} else if (DUK_HOBJECT_IS_BOUNDFUNC(obj)) {
			duk_push_sprintf(thr, "function %s() { [bound code] }", (const char *) func_name);
		} else {
			goto type_error;
		}
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		duk_push_lightfunc_tostring(thr, tv);
	} else {
		goto type_error;
	}

	return 1;

 type_error:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}
#endif

/* Always present because the native function pointer is needed in call
 * handling.
 */
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_call(duk_hthread *thr) {
	/* .call() is dealt with in call handling by simulating its
	 * effects so this function is actually never called.
	 */
	DUK_UNREF(thr);
	return DUK_RET_TYPE_ERROR;
}

DUK_INTERNAL duk_ret_t duk_bi_function_prototype_apply(duk_hthread *thr) {
	/* Like .call(), never actually called. */
	DUK_UNREF(thr);
	return DUK_RET_TYPE_ERROR;
}

DUK_INTERNAL duk_ret_t duk_bi_reflect_apply(duk_hthread *thr) {
	/* Like .call(), never actually called. */
	DUK_UNREF(thr);
	return DUK_RET_TYPE_ERROR;
}

DUK_INTERNAL duk_ret_t duk_bi_reflect_construct(duk_hthread *thr) {
	/* Like .call(), never actually called. */
	DUK_UNREF(thr);
	return DUK_RET_TYPE_ERROR;
}

#if defined(DUK_USE_FUNCTION_BUILTIN)
/* Create a bound function which points to a target function which may
 * be bound or non-bound.  If the target is bound, the argument lists
 * and 'this' binding of the functions are merged and the resulting
 * function points directly to the non-bound target.
 */
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_bind(duk_hthread *thr) {
	duk_hboundfunc *h_bound;
	duk_idx_t nargs;  /* bound args, not counting 'this' binding */
	duk_idx_t bound_nargs;
	duk_int_t bound_len;
	duk_tval *tv_prevbound;
	duk_idx_t n_prevbound;
	duk_tval *tv_res;
	duk_tval *tv_tmp;

	/* XXX: C API call, e.g. duk_push_bound_function(thr, target_idx, nargs); */

	/* Vararg function, careful arg handling, e.g. thisArg may not
	 * be present.
	 */
	nargs = duk_get_top(thr) - 1;  /* actual args, not counting 'this' binding */
	if (nargs < 0) {
		nargs++;
		duk_push_undefined(thr);
	}
	DUK_ASSERT(nargs >= 0);

	/* Limit 'nargs' for bound functions to guarantee arithmetic
	 * below will never wrap.
	 */
	if (nargs > (duk_idx_t) DUK_HBOUNDFUNC_MAX_ARGS) {
		DUK_DCERROR_RANGE_INVALID_COUNT(thr);
	}

	duk_push_this(thr);
	duk_require_callable(thr, -1);

	/* [ thisArg arg1 ... argN func ]  (thisArg+args == nargs+1 total) */
	DUK_ASSERT_TOP(thr, nargs + 2);

	/* Create bound function object. */
	h_bound = duk_push_hboundfunc(thr);
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&h_bound->target));
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&h_bound->this_binding));
	DUK_ASSERT(h_bound->args == NULL);
	DUK_ASSERT(h_bound->nargs == 0);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_bound) == NULL);

	/* [ thisArg arg1 ... argN func boundFunc ] */

	/* If the target is a bound function, argument lists must be
	 * merged.  The 'this' binding closest to the target function
	 * wins because in call handling the 'this' gets replaced over
	 * and over again until we call the non-bound function.
	 */
	tv_prevbound = NULL;
	n_prevbound = 0;
	tv_tmp = DUK_GET_TVAL_POSIDX(thr, 0);
	DUK_TVAL_SET_TVAL(&h_bound->this_binding, tv_tmp);
	tv_tmp = DUK_GET_TVAL_NEGIDX(thr, -2);
	DUK_TVAL_SET_TVAL(&h_bound->target, tv_tmp);

	if (DUK_TVAL_IS_OBJECT(tv_tmp)) {
		duk_hobject *h_target;
		duk_hobject *bound_proto;

		h_target = DUK_TVAL_GET_OBJECT(tv_tmp);
		DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(h_target));

		/* Internal prototype must be copied from the target.
		 * For lightfuncs Function.prototype is used and is already
		 * in place.
		 */
		bound_proto = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_target);
		DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) h_bound, bound_proto);

		/* The 'strict' flag is copied to get the special [[Get]] of E5.1
		 * Section 15.3.5.4 to apply when a 'caller' value is a strict bound
		 * function.  Not sure if this is correct, because the specification
		 * is a bit ambiguous on this point but it would make sense.
		 */
		/* Strictness is inherited from target. */
		if (DUK_HOBJECT_HAS_STRICT(h_target)) {
			DUK_HOBJECT_SET_STRICT((duk_hobject *) h_bound);
		}

		if (DUK_HOBJECT_HAS_BOUNDFUNC(h_target)) {
			duk_hboundfunc *h_boundtarget;

			h_boundtarget = (duk_hboundfunc *) (void *) h_target;

			/* The final function should always be non-bound, unless
			 * there's a bug in the internals.  Assert for it.
			 */
			DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(&h_boundtarget->target) ||
			           (DUK_TVAL_IS_OBJECT(&h_boundtarget->target) &&
			            DUK_HOBJECT_IS_CALLABLE(DUK_TVAL_GET_OBJECT(&h_boundtarget->target)) &&
			            !DUK_HOBJECT_IS_BOUNDFUNC(DUK_TVAL_GET_OBJECT(&h_boundtarget->target))));

			DUK_TVAL_SET_TVAL(&h_bound->target, &h_boundtarget->target);
			DUK_TVAL_SET_TVAL(&h_bound->this_binding, &h_boundtarget->this_binding);

			tv_prevbound = h_boundtarget->args;
			n_prevbound = h_boundtarget->nargs;
		}
	} else {
		/* Lightfuncs are always strict. */
		duk_hobject *bound_proto;

		DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_tmp));
		DUK_HOBJECT_SET_STRICT((duk_hobject *) h_bound);
		bound_proto = thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE];
		DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) h_bound, bound_proto);
	}

	DUK_TVAL_INCREF(thr, &h_bound->target);  /* old values undefined, no decref needed */
	DUK_TVAL_INCREF(thr, &h_bound->this_binding);

	bound_nargs = n_prevbound + nargs;
	if (bound_nargs > (duk_idx_t) DUK_HBOUNDFUNC_MAX_ARGS) {
		DUK_DCERROR_RANGE_INVALID_COUNT(thr);
	}
	tv_res = (duk_tval *) DUK_ALLOC_CHECKED(thr, ((duk_size_t) bound_nargs) * sizeof(duk_tval));
	DUK_ASSERT(tv_res != NULL || bound_nargs == 0);
	DUK_ASSERT(h_bound->args == NULL);
	DUK_ASSERT(h_bound->nargs == 0);
	h_bound->args = tv_res;
	h_bound->nargs = bound_nargs;

	DUK_ASSERT(n_prevbound >= 0);
	duk_copy_tvals_incref(thr, tv_res, tv_prevbound, (duk_size_t) n_prevbound);
	DUK_ASSERT(nargs >= 0);
	duk_copy_tvals_incref(thr, tv_res + n_prevbound, DUK_GET_TVAL_POSIDX(thr, 1), (duk_size_t) nargs);

	/* [ thisArg arg1 ... argN func boundFunc ] */

	/* Bound function 'length' property is interesting.
	 * For lightfuncs, simply read the virtual property.
	 */
	duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH);
	bound_len = duk_get_int(thr, -1);  /* ES2015: no coercion */
	if (bound_len < nargs) {
		bound_len = 0;
	} else {
		bound_len -= nargs;
	}
	if (sizeof(duk_int_t) > 4 && bound_len > (duk_int_t) DUK_UINT32_MAX) {
		bound_len = (duk_int_t) DUK_UINT32_MAX;
	}
	duk_pop(thr);
	DUK_ASSERT(bound_len >= 0);
	tv_tmp = thr->valstack_top++;
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv_tmp));
	DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv_tmp));
	DUK_TVAL_SET_U32(tv_tmp, (duk_uint32_t) bound_len);  /* in-place update, fastint */
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_C);  /* attrs in E6 Section 9.2.4 */

	/* XXX: could these be virtual? */
	/* Caller and arguments must use the same thrower, [[ThrowTypeError]]. */
	duk_xdef_prop_stridx_thrower(thr, -1, DUK_STRIDX_CALLER);
	duk_xdef_prop_stridx_thrower(thr, -1, DUK_STRIDX_LC_ARGUMENTS);

	/* Function name and fileName (non-standard). */
	duk_push_literal(thr, "bound ");  /* ES2015 19.2.3.2. */
	duk_get_prop_stridx(thr, -3, DUK_STRIDX_NAME);
	if (!duk_is_string_notsymbol(thr, -1)) {
		/* ES2015 has requirement to check that .name of target is a string
		 * (also must check for Symbol); if not, targetName should be the
		 * empty string.  ES2015 19.2.3.2.
		 */
		duk_pop(thr);
		duk_push_hstring_empty(thr);
	}
	duk_concat(thr, 2);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);
#if defined(DUK_USE_FUNC_FILENAME_PROPERTY)
	duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_FILE_NAME);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_C);
#endif

	DUK_DDD(DUK_DDDPRINT("created bound function: %!iT", (duk_tval *) duk_get_tval(thr, -1)));

	return 1;
}
#endif  /* DUK_USE_FUNCTION_BUILTIN */

/* %NativeFunctionPrototype% .length getter. */
DUK_INTERNAL duk_ret_t duk_bi_native_function_length(duk_hthread *thr) {
	duk_tval *tv;
	duk_hnatfunc *h;
	duk_int16_t func_nargs;

	tv = duk_get_borrowed_this_tval(thr);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_OBJECT(tv)) {
		h = (duk_hnatfunc *) DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (!DUK_HOBJECT_IS_NATFUNC((duk_hobject *) h)) {
			goto fail_type;
		}
		func_nargs = h->nargs;
		duk_push_int(thr, func_nargs == DUK_HNATFUNC_NARGS_VARARGS ? 0 : func_nargs);
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		duk_small_uint_t lf_flags;
		duk_small_uint_t lf_len;

		lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv);
		lf_len = DUK_LFUNC_FLAGS_GET_LENGTH(lf_flags);
		duk_push_uint(thr, lf_len);
	} else {
		goto fail_type;
	}
	return 1;

 fail_type:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}

/* %NativeFunctionPrototype% .name getter. */
DUK_INTERNAL duk_ret_t duk_bi_native_function_name(duk_hthread *thr) {
	duk_tval *tv;
	duk_hnatfunc *h;

	tv = duk_get_borrowed_this_tval(thr);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_OBJECT(tv)) {
		h = (duk_hnatfunc *) DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		if (!DUK_HOBJECT_IS_NATFUNC((duk_hobject *) h)) {
			goto fail_type;
		}
#if 0
		duk_push_hnatfunc_name(thr, h);
#endif
		duk_push_hstring_empty(thr);
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
		duk_push_lightfunc_name(thr, tv);
	} else {
		goto fail_type;
	}
	return 1;

 fail_type:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}

#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_hasinstance(duk_hthread *thr) {
	/* This binding: RHS, stack index 0: LHS. */
	duk_bool_t ret;

	ret = duk_js_instanceof_ordinary(thr, DUK_GET_TVAL_POSIDX(thr, 0), DUK_GET_THIS_TVAL_PTR(thr));
	duk_push_boolean(thr, ret);
	return 1;
}
#endif  /* DUK_USE_SYMBOL_BUILTIN */
/*
 *  Global object built-ins
 */

/* #include duk_internal.h -> already included */

/*
 *  Encoding/decoding helpers
 */

/* XXX: Could add fast path (for each transform callback) with direct byte
 * lookups (no shifting) and no explicit check for x < 0x80 before table
 * lookup.
 */

/* Macros for creating and checking bitmasks for character encoding.
 * Bit number is a bit counterintuitive, but minimizes code size.
 */
#define DUK__MKBITS(a,b,c,d,e,f,g,h)  ((duk_uint8_t) ( \
	((a) << 0) | ((b) << 1) | ((c) << 2) | ((d) << 3) | \
	((e) << 4) | ((f) << 5) | ((g) << 6) | ((h) << 7) \
	))
#define DUK__CHECK_BITMASK(table,cp)  ((table)[(cp) >> 3] & (1 << ((cp) & 0x07)))

/* E5.1 Section 15.1.3.3: uriReserved + uriUnescaped + '#' */
DUK_LOCAL const duk_uint8_t duk__encode_uriunescaped_table[16] = {
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x00-0x0f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x10-0x1f */
	DUK__MKBITS(0, 1, 0, 1, 1, 0, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x20-0x2f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 0, 1, 0, 1),  /* 0x30-0x3f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x40-0x4f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 0, 1),  /* 0x50-0x5f */
	DUK__MKBITS(0, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x60-0x6f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 1, 0),  /* 0x70-0x7f */
};

/* E5.1 Section 15.1.3.4: uriUnescaped */
DUK_LOCAL const duk_uint8_t duk__encode_uricomponent_unescaped_table[16] = {
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x00-0x0f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x10-0x1f */
	DUK__MKBITS(0, 1, 0, 0, 0, 0, 0, 1), DUK__MKBITS(1, 1, 1, 0, 0, 1, 1, 0),  /* 0x20-0x2f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 0, 0, 0, 0, 0, 0),  /* 0x30-0x3f */
	DUK__MKBITS(0, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x40-0x4f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 0, 1),  /* 0x50-0x5f */
	DUK__MKBITS(0, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x60-0x6f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 1, 0),  /* 0x70-0x7f */
};

/* E5.1 Section 15.1.3.1: uriReserved + '#' */
DUK_LOCAL const duk_uint8_t duk__decode_uri_reserved_table[16] = {
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x00-0x0f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x10-0x1f */
	DUK__MKBITS(0, 0, 0, 1, 1, 0, 1, 0), DUK__MKBITS(0, 0, 0, 1, 1, 0, 0, 1),  /* 0x20-0x2f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 1, 1, 0, 1, 0, 1),  /* 0x30-0x3f */
	DUK__MKBITS(1, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x40-0x4f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x50-0x5f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x60-0x6f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x70-0x7f */
};

/* E5.1 Section 15.1.3.2: empty */
DUK_LOCAL const duk_uint8_t duk__decode_uri_component_reserved_table[16] = {
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x00-0x0f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x10-0x1f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x20-0x2f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x30-0x3f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x40-0x4f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x50-0x5f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x60-0x6f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x70-0x7f */
};

#if defined(DUK_USE_SECTION_B)
/* E5.1 Section B.2.2, step 7. */
DUK_LOCAL const duk_uint8_t duk__escape_unescaped_table[16] = {
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x00-0x0f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0),  /* 0x10-0x1f */
	DUK__MKBITS(0, 0, 0, 0, 0, 0, 0, 0), DUK__MKBITS(0, 0, 1, 1, 0, 1, 1, 1),  /* 0x20-0x2f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 0, 0, 0, 0, 0, 0),  /* 0x30-0x3f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x40-0x4f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 0, 1),  /* 0x50-0x5f */
	DUK__MKBITS(0, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1),  /* 0x60-0x6f */
	DUK__MKBITS(1, 1, 1, 1, 1, 1, 1, 1), DUK__MKBITS(1, 1, 1, 0, 0, 0, 0, 0)   /* 0x70-0x7f */
};
#endif  /* DUK_USE_SECTION_B */

typedef struct {
	duk_hthread *thr;
	duk_hstring *h_str;
	duk_bufwriter_ctx bw;
	const duk_uint8_t *p;
	const duk_uint8_t *p_start;
	const duk_uint8_t *p_end;
} duk__transform_context;

typedef void (*duk__transform_callback)(duk__transform_context *tfm_ctx, const void *udata, duk_codepoint_t cp);

/* XXX: refactor and share with other code */
DUK_LOCAL duk_small_int_t duk__decode_hex_escape(const duk_uint8_t *p, duk_small_int_t n) {
	duk_small_int_t ch;
	duk_small_int_t t = 0;

	while (n > 0) {
		t = t * 16;
		ch = (duk_small_int_t) duk_hex_dectab[*p++];
		if (DUK_LIKELY(ch >= 0)) {
			t += ch;
		} else {
			return -1;
		}
		n--;
	}
	return t;
}

DUK_LOCAL int duk__transform_helper(duk_hthread *thr, duk__transform_callback callback, const void *udata) {
	duk__transform_context tfm_ctx_alloc;
	duk__transform_context *tfm_ctx = &tfm_ctx_alloc;
	duk_codepoint_t cp;

	tfm_ctx->thr = thr;

	tfm_ctx->h_str = duk_to_hstring(thr, 0);
	DUK_ASSERT(tfm_ctx->h_str != NULL);

	DUK_BW_INIT_PUSHBUF(thr, &tfm_ctx->bw, DUK_HSTRING_GET_BYTELEN(tfm_ctx->h_str));  /* initial size guess */

	tfm_ctx->p_start = DUK_HSTRING_GET_DATA(tfm_ctx->h_str);
	tfm_ctx->p_end = tfm_ctx->p_start + DUK_HSTRING_GET_BYTELEN(tfm_ctx->h_str);
	tfm_ctx->p = tfm_ctx->p_start;

	while (tfm_ctx->p < tfm_ctx->p_end) {
		cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &tfm_ctx->p, tfm_ctx->p_start, tfm_ctx->p_end);
		callback(tfm_ctx, udata, cp);
	}

	DUK_BW_COMPACT(thr, &tfm_ctx->bw);

	(void) duk_buffer_to_string(thr, -1);  /* Safe if transform is safe. */
	return 1;
}

DUK_LOCAL void duk__transform_callback_encode_uri(duk__transform_context *tfm_ctx, const void *udata, duk_codepoint_t cp) {
	duk_uint8_t xutf8_buf[DUK_UNICODE_MAX_XUTF8_LENGTH];
	duk_small_int_t len;
	duk_codepoint_t cp1, cp2;
	duk_small_int_t i, t;
	const duk_uint8_t *unescaped_table = (const duk_uint8_t *) udata;

	/* UTF-8 encoded bytes escaped as %xx%xx%xx... -> 3 * nbytes.
	 * Codepoint range is restricted so this is a slightly too large
	 * but doesn't matter.
	 */
	DUK_BW_ENSURE(tfm_ctx->thr, &tfm_ctx->bw, 3 * DUK_UNICODE_MAX_XUTF8_LENGTH);

	if (cp < 0) {
		goto uri_error;
	} else if ((cp < 0x80L) && DUK__CHECK_BITMASK(unescaped_table, cp)) {
		DUK_BW_WRITE_RAW_U8(tfm_ctx->thr, &tfm_ctx->bw, (duk_uint8_t) cp);
		return;
	} else if (cp >= 0xdc00L && cp <= 0xdfffL) {
		goto uri_error;
	} else if (cp >= 0xd800L && cp <= 0xdbffL) {
		/* Needs lookahead */
		if (duk_unicode_decode_xutf8(tfm_ctx->thr, &tfm_ctx->p, tfm_ctx->p_start, tfm_ctx->p_end, (duk_ucodepoint_t *) &cp2) == 0) {
			goto uri_error;
		}
		if (!(cp2 >= 0xdc00L && cp2 <= 0xdfffL)) {
			goto uri_error;
		}
		cp1 = cp;
		cp = (duk_codepoint_t) (((cp1 - 0xd800L) << 10) + (cp2 - 0xdc00L) + 0x10000L);
	} else if (cp > 0x10ffffL) {
		/* Although we can allow non-BMP characters (they'll decode
		 * back into surrogate pairs), we don't allow extended UTF-8
		 * characters; they would encode to URIs which won't decode
		 * back because of strict UTF-8 checks in URI decoding.
		 * (However, we could just as well allow them here.)
		 */
		goto uri_error;
	} else {
		/* Non-BMP characters within valid UTF-8 range: encode as is.
		 * They'll decode back into surrogate pairs if the escaped
		 * output is decoded.
		 */
		;
	}

	len = duk_unicode_encode_xutf8((duk_ucodepoint_t) cp, xutf8_buf);
	for (i = 0; i < len; i++) {
		t = (duk_small_int_t) xutf8_buf[i];
		DUK_BW_WRITE_RAW_U8_3(tfm_ctx->thr,
		                      &tfm_ctx->bw,
		                      DUK_ASC_PERCENT,
		                      (duk_uint8_t) duk_uc_nybbles[t >> 4],
                                      (duk_uint8_t) duk_uc_nybbles[t & 0x0f]);
	}

	return;

 uri_error:
	DUK_ERROR_URI(tfm_ctx->thr, DUK_STR_INVALID_INPUT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__transform_callback_decode_uri(duk__transform_context *tfm_ctx, const void *udata, duk_codepoint_t cp) {
	const duk_uint8_t *reserved_table = (const duk_uint8_t *) udata;
	duk_small_uint_t utf8_blen;
	duk_codepoint_t min_cp;
	duk_small_int_t t;  /* must be signed */
	duk_small_uint_t i;

	/* Maximum write size: XUTF8 path writes max DUK_UNICODE_MAX_XUTF8_LENGTH,
	 * percent escape path writes max two times CESU-8 encoded BMP length.
	 */
	DUK_BW_ENSURE(tfm_ctx->thr,
	              &tfm_ctx->bw,
	              (DUK_UNICODE_MAX_XUTF8_LENGTH >= 2 * DUK_UNICODE_MAX_CESU8_BMP_LENGTH ?
	              DUK_UNICODE_MAX_XUTF8_LENGTH : DUK_UNICODE_MAX_CESU8_BMP_LENGTH));

	if (cp == (duk_codepoint_t) '%') {
		const duk_uint8_t *p = tfm_ctx->p;
		duk_size_t left = (duk_size_t) (tfm_ctx->p_end - p);  /* bytes left */

		DUK_DDD(DUK_DDDPRINT("percent encoding, left=%ld", (long) left));

		if (left < 2) {
			goto uri_error;
		}

		t = duk__decode_hex_escape(p, 2);
		DUK_DDD(DUK_DDDPRINT("first byte: %ld", (long) t));
		if (t < 0) {
			goto uri_error;
		}

		if (t < 0x80) {
			if (DUK__CHECK_BITMASK(reserved_table, t)) {
				/* decode '%xx' to '%xx' if decoded char in reserved set */
				DUK_ASSERT(tfm_ctx->p - 1 >= tfm_ctx->p_start);
				DUK_BW_WRITE_RAW_U8_3(tfm_ctx->thr,
				                      &tfm_ctx->bw,
				                      DUK_ASC_PERCENT,
				                      p[0],
				                      p[1]);
			} else {
				DUK_BW_WRITE_RAW_U8(tfm_ctx->thr, &tfm_ctx->bw, (duk_uint8_t) t);
			}
			tfm_ctx->p += 2;
			return;
		}

		/* Decode UTF-8 codepoint from a sequence of hex escapes.  The
		 * first byte of the sequence has been decoded to 't'.
		 *
		 * Note that UTF-8 validation must be strict according to the
		 * specification: E5.1 Section 15.1.3, decode algorithm step
		 * 4.d.vii.8.  URIError from non-shortest encodings is also
		 * specifically noted in the spec.
		 */

		DUK_ASSERT(t >= 0x80);
		if (t < 0xc0) {
			/* continuation byte */
			goto uri_error;
		} else if (t < 0xe0) {
			/* 110x xxxx; 2 bytes */
			utf8_blen = 2;
			min_cp = 0x80L;
			cp = t & 0x1f;
		} else if (t < 0xf0) {
			/* 1110 xxxx; 3 bytes */
			utf8_blen = 3;
			min_cp = 0x800L;
			cp = t & 0x0f;
		} else if (t < 0xf8) {
			/* 1111 0xxx; 4 bytes */
			utf8_blen = 4;
			min_cp = 0x10000L;
			cp = t & 0x07;
		} else {
			/* extended utf-8 not allowed for URIs */
			goto uri_error;
		}

		if (left < utf8_blen * 3 - 1) {
			/* '%xx%xx...%xx', p points to char after first '%' */
			goto uri_error;
		}

		p += 3;
		for (i = 1; i < utf8_blen; i++) {
			/* p points to digit part ('%xy', p points to 'x') */
			t = duk__decode_hex_escape(p, 2);
			DUK_DDD(DUK_DDDPRINT("i=%ld utf8_blen=%ld cp=%ld t=0x%02lx",
			                     (long) i, (long) utf8_blen, (long) cp, (unsigned long) t));
			if (t < 0) {
				goto uri_error;
			}
			if ((t & 0xc0) != 0x80) {
				goto uri_error;
			}
			cp = (cp << 6) + (t & 0x3f);
			p += 3;
		}
		p--;  /* p overshoots */
		tfm_ctx->p = p;

		DUK_DDD(DUK_DDDPRINT("final cp=%ld, min_cp=%ld", (long) cp, (long) min_cp));

		if (cp < min_cp || cp > 0x10ffffL || (cp >= 0xd800L && cp <= 0xdfffL)) {
			goto uri_error;
		}

		/* The E5.1 algorithm checks whether or not a decoded codepoint
		 * is below 0x80 and perhaps may be in the "reserved" set.
		 * This seems pointless because the single byte UTF-8 case is
		 * handled separately, and non-shortest encodings are rejected.
		 * So, 'cp' cannot be below 0x80 here, and thus cannot be in
		 * the reserved set.
		 */

		/* utf-8 validation ensures these */
		DUK_ASSERT(cp >= 0x80L && cp <= 0x10ffffL);

		if (cp >= 0x10000L) {
			cp -= 0x10000L;
			DUK_ASSERT(cp < 0x100000L);

			DUK_BW_WRITE_RAW_XUTF8(tfm_ctx->thr, &tfm_ctx->bw, ((cp >> 10) + 0xd800L));
			DUK_BW_WRITE_RAW_XUTF8(tfm_ctx->thr, &tfm_ctx->bw, ((cp & 0x03ffL) + 0xdc00L));
		} else {
			DUK_BW_WRITE_RAW_XUTF8(tfm_ctx->thr, &tfm_ctx->bw, cp);
		}
	} else {
		DUK_BW_WRITE_RAW_XUTF8(tfm_ctx->thr, &tfm_ctx->bw, cp);
	}
	return;

 uri_error:
	DUK_ERROR_URI(tfm_ctx->thr, DUK_STR_INVALID_INPUT);
	DUK_WO_NORETURN(return;);
}

#if defined(DUK_USE_SECTION_B)
DUK_LOCAL void duk__transform_callback_escape(duk__transform_context *tfm_ctx, const void *udata, duk_codepoint_t cp) {
	DUK_UNREF(udata);

	DUK_BW_ENSURE(tfm_ctx->thr, &tfm_ctx->bw, 6);

	if (cp < 0) {
		goto esc_error;
	} else if ((cp < 0x80L) && DUK__CHECK_BITMASK(duk__escape_unescaped_table, cp)) {
		DUK_BW_WRITE_RAW_U8(tfm_ctx->thr, &tfm_ctx->bw, (duk_uint8_t) cp);
	} else if (cp < 0x100L) {
		DUK_BW_WRITE_RAW_U8_3(tfm_ctx->thr,
		                      &tfm_ctx->bw,
		                      (duk_uint8_t) DUK_ASC_PERCENT,
		                      (duk_uint8_t) duk_uc_nybbles[cp >> 4],
		                      (duk_uint8_t) duk_uc_nybbles[cp & 0x0f]);
	} else if (cp < 0x10000L) {
		DUK_BW_WRITE_RAW_U8_6(tfm_ctx->thr,
		                      &tfm_ctx->bw,
		                      (duk_uint8_t) DUK_ASC_PERCENT,
		                      (duk_uint8_t) DUK_ASC_LC_U,
		                      (duk_uint8_t) duk_uc_nybbles[cp >> 12],
		                      (duk_uint8_t) duk_uc_nybbles[(cp >> 8) & 0x0f],
		                      (duk_uint8_t) duk_uc_nybbles[(cp >> 4) & 0x0f],
		                      (duk_uint8_t) duk_uc_nybbles[cp & 0x0f]);
	} else {
		/* Characters outside BMP cannot be escape()'d.  We could
		 * encode them as surrogate pairs (for codepoints inside
		 * valid UTF-8 range, but not extended UTF-8).  Because
		 * escape() and unescape() are legacy functions, we don't.
		 */
		goto esc_error;
	}

	return;

 esc_error:
	DUK_ERROR_TYPE(tfm_ctx->thr, DUK_STR_INVALID_INPUT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__transform_callback_unescape(duk__transform_context *tfm_ctx, const void *udata, duk_codepoint_t cp) {
	duk_small_int_t t;

	DUK_UNREF(udata);

	if (cp == (duk_codepoint_t) '%') {
		const duk_uint8_t *p = tfm_ctx->p;
		duk_size_t left = (duk_size_t) (tfm_ctx->p_end - p);  /* bytes left */

		if (left >= 5 && p[0] == 'u' &&
		    ((t = duk__decode_hex_escape(p + 1, 4)) >= 0)) {
			cp = (duk_codepoint_t) t;
			tfm_ctx->p += 5;
		} else if (left >= 2 &&
		           ((t = duk__decode_hex_escape(p, 2)) >= 0)) {
			cp = (duk_codepoint_t) t;
			tfm_ctx->p += 2;
		}
	}

	DUK_BW_WRITE_ENSURE_XUTF8(tfm_ctx->thr, &tfm_ctx->bw, cp);
}
#endif  /* DUK_USE_SECTION_B */

/*
 *  Eval
 *
 *  Eval needs to handle both a "direct eval" and an "indirect eval".
 *  Direct eval handling needs access to the caller's activation so that its
 *  lexical environment can be accessed.  A direct eval is only possible from
 *  ECMAScript code; an indirect eval call is possible also from C code.
 *  When an indirect eval call is made from C code, there may not be a
 *  calling activation at all which needs careful handling.
 */

DUK_INTERNAL duk_ret_t duk_bi_global_object_eval(duk_hthread *thr) {
	duk_hstring *h;
	duk_activation *act_caller;
	duk_activation *act_eval;
	duk_hcompfunc *func;
	duk_hobject *outer_lex_env;
	duk_hobject *outer_var_env;
	duk_bool_t this_to_global = 1;
	duk_small_uint_t comp_flags;
	duk_int_t level = -2;
	duk_small_uint_t call_flags;

	DUK_ASSERT(duk_get_top(thr) == 1 || duk_get_top(thr) == 2);  /* 2 when called by debugger */
	DUK_ASSERT(thr->callstack_top >= 1);  /* at least this function exists */
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT((thr->callstack_curr->flags & DUK_ACT_FLAG_DIRECT_EVAL) == 0 || /* indirect eval */
	           (thr->callstack_top >= 2));  /* if direct eval, calling activation must exist */

	/*
	 *  callstack_top - 1 --> this function
	 *  callstack_top - 2 --> caller (may not exist)
	 *
	 *  If called directly from C, callstack_top might be 1.  If calling
	 *  activation doesn't exist, call must be indirect.
	 */

	h = duk_get_hstring_notsymbol(thr, 0);
	if (!h) {
		/* Symbol must be returned as is, like any non-string values. */
		return 1;  /* return arg as-is */
	}

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	/* NOTE: level is used only by the debugger and should never be present
	 * for an ECMAScript eval().
	 */
	DUK_ASSERT(level == -2);  /* by default, use caller's environment */
	if (duk_get_top(thr) >= 2 && duk_is_number(thr, 1)) {
		level = duk_get_int(thr, 1);
	}
	DUK_ASSERT(level <= -2);  /* This is guaranteed by debugger code. */
#endif

	/* [ source ] */

	comp_flags = DUK_COMPILE_EVAL;
	act_eval = thr->callstack_curr;  /* this function */
	DUK_ASSERT(act_eval != NULL);
	act_caller = duk_hthread_get_activation_for_level(thr, level);
	if (act_caller != NULL) {
		/* Have a calling activation, check for direct eval (otherwise
		 * assume indirect eval.
		 */
		if ((act_caller->flags & DUK_ACT_FLAG_STRICT) &&
		    (act_eval->flags & DUK_ACT_FLAG_DIRECT_EVAL)) {
			/* Only direct eval inherits strictness from calling code
			 * (E5.1 Section 10.1.1).
			 */
			comp_flags |= DUK_COMPILE_STRICT;
		}
	} else {
		DUK_ASSERT((act_eval->flags & DUK_ACT_FLAG_DIRECT_EVAL) == 0);
	}

	duk_push_hstring_stridx(thr, DUK_STRIDX_INPUT);  /* XXX: copy from caller? */
	duk_js_compile(thr,
	               (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h),
	               (duk_size_t) DUK_HSTRING_GET_BYTELEN(h),
	               comp_flags);
	func = (duk_hcompfunc *) duk_known_hobject(thr, -1);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) func));

	/* [ source template ] */

	/* E5 Section 10.4.2 */

	if (act_eval->flags & DUK_ACT_FLAG_DIRECT_EVAL) {
		DUK_ASSERT(thr->callstack_top >= 2);
		DUK_ASSERT(act_caller != NULL);
		if (act_caller->lex_env == NULL) {
			DUK_ASSERT(act_caller->var_env == NULL);
			DUK_DDD(DUK_DDDPRINT("delayed environment initialization"));

			/* this may have side effects, so re-lookup act */
			duk_js_init_activation_environment_records_delayed(thr, act_caller);
		}
		DUK_ASSERT(act_caller->lex_env != NULL);
		DUK_ASSERT(act_caller->var_env != NULL);

		this_to_global = 0;

		if (DUK_HOBJECT_HAS_STRICT((duk_hobject *) func)) {
			duk_hdecenv *new_env;
			duk_hobject *act_lex_env;

			DUK_DDD(DUK_DDDPRINT("direct eval call to a strict function -> "
			                     "var_env and lex_env to a fresh env, "
			                     "this_binding to caller's this_binding"));

			act_lex_env = act_caller->lex_env;

			new_env = duk_hdecenv_alloc(thr,
			                            DUK_HOBJECT_FLAG_EXTENSIBLE |
			                            DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV));
			DUK_ASSERT(new_env != NULL);
			duk_push_hobject(thr, (duk_hobject *) new_env);

			DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) new_env) == NULL);
			DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) new_env, act_lex_env);
			DUK_HOBJECT_INCREF_ALLOWNULL(thr, act_lex_env);
			DUK_DDD(DUK_DDDPRINT("new_env allocated: %!iO", (duk_heaphdr *) new_env));

			outer_lex_env = (duk_hobject *) new_env;
			outer_var_env = (duk_hobject *) new_env;

			duk_insert(thr, 0);  /* stash to bottom of value stack to keep new_env reachable for duration of eval */

			/* compiler's responsibility */
			DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV((duk_hobject *) func));
		} else {
			DUK_DDD(DUK_DDDPRINT("direct eval call to a non-strict function -> "
			                     "var_env and lex_env to caller's envs, "
			                     "this_binding to caller's this_binding"));

			outer_lex_env = act_caller->lex_env;
			outer_var_env = act_caller->var_env;

			/* compiler's responsibility */
			DUK_ASSERT(!DUK_HOBJECT_HAS_NEWENV((duk_hobject *) func));
		}
	} else {
		DUK_DDD(DUK_DDDPRINT("indirect eval call -> var_env and lex_env to "
		                     "global object, this_binding to global object"));

		this_to_global = 1;
		outer_lex_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
		outer_var_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
	}

	/* Eval code doesn't need an automatic .prototype object. */
	duk_js_push_closure(thr, func, outer_var_env, outer_lex_env, 0 /*add_auto_proto*/);

	/* [ env? source template closure ] */

	if (this_to_global) {
		DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);
		duk_push_hobject_bidx(thr, DUK_BIDX_GLOBAL);
	} else {
		duk_tval *tv;
		DUK_ASSERT(thr->callstack_top >= 2);
		DUK_ASSERT(act_caller != NULL);
		tv = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act_caller->bottom_byteoff - sizeof(duk_tval));  /* this is just beneath bottom */
		DUK_ASSERT(tv >= thr->valstack);
		duk_push_tval(thr, tv);
	}

	DUK_DDD(DUK_DDDPRINT("eval -> lex_env=%!iO, var_env=%!iO, this_binding=%!T",
	                     (duk_heaphdr *) outer_lex_env,
	                     (duk_heaphdr *) outer_var_env,
	                     duk_get_tval(thr, -1)));

	/* [ env? source template closure this ] */

	call_flags = 0;
	if (act_eval->flags & DUK_ACT_FLAG_DIRECT_EVAL) {
		/* Set DIRECT_EVAL flag for the call; it's not strictly
		 * needed for the 'inner' eval call (the eval body) but
		 * current new.target implementation expects to find it
		 * so it can traverse direct eval chains up to the real
		 * calling function.
		 */
		call_flags |= DUK_CALL_FLAG_DIRECT_EVAL;
	}
	duk_handle_call_unprotected_nargs(thr, 0, call_flags);

	/* [ env? source template result ] */

	return 1;
}

/*
 *  Parsing of ints and floats
 */

#if defined(DUK_USE_GLOBAL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_global_object_parse_int(duk_hthread *thr) {
	duk_int32_t radix;
	duk_small_uint_t s2n_flags;

	DUK_ASSERT_TOP(thr, 2);
	duk_to_string(thr, 0);  /* Reject symbols. */

	radix = duk_to_int32(thr, 1);

	/* While parseInt() recognizes 0xdeadbeef, it doesn't recognize
	 * ES2015 0o123 or 0b10001.
	 */
	s2n_flags = DUK_S2N_FLAG_TRIM_WHITE |
	            DUK_S2N_FLAG_ALLOW_GARBAGE |
	            DUK_S2N_FLAG_ALLOW_PLUS |
	            DUK_S2N_FLAG_ALLOW_MINUS |
	            DUK_S2N_FLAG_ALLOW_LEADING_ZERO |
	            DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT;

	/* Specification stripPrefix maps to DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT.
	 *
	 * Don't autodetect octals (from leading zeroes), require user code to
	 * provide an explicit radix 8 for parsing octal.  See write-up from Mozilla:
	 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt#ECMAScript_5_Removes_Octal_Interpretation
	 */

	if (radix != 0) {
		if (radix < 2 || radix > 36) {
			goto ret_nan;
		}
		if (radix != 16) {
			s2n_flags &= ~DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT;
		}
	} else {
		radix = 10;
	}

	duk_dup_0(thr);
	duk_numconv_parse(thr, (duk_small_int_t) radix, s2n_flags);
	return 1;

 ret_nan:
	duk_push_nan(thr);
	return 1;
}
#endif  /* DUK_USE_GLOBAL_BUILTIN */

#if defined(DUK_USE_GLOBAL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_global_object_parse_float(duk_hthread *thr) {
	duk_small_uint_t s2n_flags;

	DUK_ASSERT_TOP(thr, 1);
	duk_to_string(thr, 0);  /* Reject symbols. */

	/* XXX: check flags */
	s2n_flags = DUK_S2N_FLAG_TRIM_WHITE |
	            DUK_S2N_FLAG_ALLOW_EXP |
	            DUK_S2N_FLAG_ALLOW_GARBAGE |
	            DUK_S2N_FLAG_ALLOW_PLUS |
	            DUK_S2N_FLAG_ALLOW_MINUS |
	            DUK_S2N_FLAG_ALLOW_INF |
	            DUK_S2N_FLAG_ALLOW_FRAC |
	            DUK_S2N_FLAG_ALLOW_NAKED_FRAC |
	            DUK_S2N_FLAG_ALLOW_EMPTY_FRAC |
	            DUK_S2N_FLAG_ALLOW_LEADING_ZERO;

	duk_numconv_parse(thr, 10 /*radix*/, s2n_flags);
	return 1;
}
#endif  /* DUK_USE_GLOBAL_BUILTIN */

/*
 *  Number checkers
 */

#if defined(DUK_USE_GLOBAL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_global_object_is_nan(duk_hthread *thr) {
	duk_double_t d = duk_to_number(thr, 0);
	duk_push_boolean(thr, (duk_bool_t) DUK_ISNAN(d));
	return 1;
}
#endif  /* DUK_USE_GLOBAL_BUILTIN */

#if defined(DUK_USE_GLOBAL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_global_object_is_finite(duk_hthread *thr) {
	duk_double_t d = duk_to_number(thr, 0);
	duk_push_boolean(thr, (duk_bool_t) DUK_ISFINITE(d));
	return 1;
}
#endif  /* DUK_USE_GLOBAL_BUILTIN */

/*
 *  URI handling
 */

#if defined(DUK_USE_GLOBAL_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_global_object_decode_uri(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_decode_uri, (const void *) duk__decode_uri_reserved_table);
}

DUK_INTERNAL duk_ret_t duk_bi_global_object_decode_uri_component(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_decode_uri, (const void *) duk__decode_uri_component_reserved_table);
}

DUK_INTERNAL duk_ret_t duk_bi_global_object_encode_uri(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_encode_uri, (const void *) duk__encode_uriunescaped_table);
}

DUK_INTERNAL duk_ret_t duk_bi_global_object_encode_uri_component(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_encode_uri, (const void *) duk__encode_uricomponent_unescaped_table);
}

#if defined(DUK_USE_SECTION_B)
DUK_INTERNAL duk_ret_t duk_bi_global_object_escape(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_escape, (const void *) NULL);
}

DUK_INTERNAL duk_ret_t duk_bi_global_object_unescape(duk_hthread *thr) {
	return duk__transform_helper(thr, duk__transform_callback_unescape, (const void *) NULL);
}
#endif  /* DUK_USE_SECTION_B */
#endif  /* DUK_USE_GLOBAL_BUILTIN */

/* automatic undefs */
#undef DUK__CHECK_BITMASK
#undef DUK__MKBITS
/*
 *  JSON built-ins.
 *
 *  See doc/json.rst.
 *
 *  Codepoints are handled as duk_uint_fast32_t to ensure that the full
 *  unsigned 32-bit range is supported.  This matters to e.g. JX.
 *
 *  Input parsing doesn't do an explicit end-of-input check at all.  This is
 *  safe: input string data is always NUL-terminated (0x00) and valid JSON
 *  inputs never contain plain NUL characters, so that as long as syntax checks
 *  are correct, we'll never read past the NUL.  This approach reduces code size
 *  and improves parsing performance, but it's critical that syntax checks are
 *  indeed correct!
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_JSON_SUPPORT)

/*
 *  Local defines and forward declarations.
 */

#define DUK__JSON_DECSTR_BUFSIZE 128
#define DUK__JSON_DECSTR_CHUNKSIZE 64
#define DUK__JSON_ENCSTR_CHUNKSIZE 64
#define DUK__JSON_STRINGIFY_BUFSIZE 128
#define DUK__JSON_MAX_ESC_LEN 10  /* '\Udeadbeef' */

DUK_LOCAL_DECL void duk__dec_syntax_error(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_eat_white(duk_json_dec_ctx *js_ctx);
#if defined(DUK_USE_JX)
DUK_LOCAL_DECL duk_uint8_t duk__dec_peek(duk_json_dec_ctx *js_ctx);
#endif
DUK_LOCAL_DECL duk_uint8_t duk__dec_get(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL duk_uint8_t duk__dec_get_nonwhite(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL duk_uint_fast32_t duk__dec_decode_hex_escape(duk_json_dec_ctx *js_ctx, duk_small_uint_t n);
DUK_LOCAL_DECL void duk__dec_req_stridx(duk_json_dec_ctx *js_ctx, duk_small_uint_t stridx);
DUK_LOCAL_DECL void duk__dec_string(duk_json_dec_ctx *js_ctx);
#if defined(DUK_USE_JX)
DUK_LOCAL_DECL void duk__dec_plain_string(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_pointer(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_buffer(duk_json_dec_ctx *js_ctx);
#endif
DUK_LOCAL_DECL void duk__dec_number(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_objarr_entry(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_objarr_exit(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_object(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_array(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_value(duk_json_dec_ctx *js_ctx);
DUK_LOCAL_DECL void duk__dec_reviver_walk(duk_json_dec_ctx *js_ctx);

DUK_LOCAL_DECL void duk__emit_1(duk_json_enc_ctx *js_ctx, duk_uint_fast8_t ch);
DUK_LOCAL_DECL void duk__emit_2(duk_json_enc_ctx *js_ctx, duk_uint_fast8_t ch1, duk_uint_fast8_t ch2);
DUK_LOCAL_DECL void duk__unemit_1(duk_json_enc_ctx *js_ctx);
DUK_LOCAL_DECL void duk__emit_hstring(duk_json_enc_ctx *js_ctx, duk_hstring *h);
#if defined(DUK_USE_FASTINT)
DUK_LOCAL_DECL void duk__emit_cstring(duk_json_enc_ctx *js_ctx, const char *p);
#endif
DUK_LOCAL_DECL void duk__emit_stridx(duk_json_enc_ctx *js_ctx, duk_small_uint_t stridx);
DUK_LOCAL_DECL duk_uint8_t *duk__emit_esc_auto_fast(duk_json_enc_ctx *js_ctx, duk_uint_fast32_t cp, duk_uint8_t *q);
DUK_LOCAL_DECL void duk__enc_key_autoquote(duk_json_enc_ctx *js_ctx, duk_hstring *k);
DUK_LOCAL_DECL void duk__enc_quote_string(duk_json_enc_ctx *js_ctx, duk_hstring *h_str);
DUK_LOCAL_DECL void duk__enc_objarr_entry(duk_json_enc_ctx *js_ctx, duk_idx_t *entry_top);
DUK_LOCAL_DECL void duk__enc_objarr_exit(duk_json_enc_ctx *js_ctx, duk_idx_t *entry_top);
DUK_LOCAL_DECL void duk__enc_object(duk_json_enc_ctx *js_ctx);
DUK_LOCAL_DECL void duk__enc_array(duk_json_enc_ctx *js_ctx);
DUK_LOCAL_DECL duk_bool_t duk__enc_value(duk_json_enc_ctx *js_ctx, duk_idx_t idx_holder);
DUK_LOCAL_DECL duk_bool_t duk__enc_allow_into_proplist(duk_tval *tv);
DUK_LOCAL_DECL void duk__enc_double(duk_json_enc_ctx *js_ctx);
#if defined(DUK_USE_FASTINT)
DUK_LOCAL_DECL void duk__enc_fastint_tval(duk_json_enc_ctx *js_ctx, duk_tval *tv);
#endif
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
DUK_LOCAL_DECL void duk__enc_buffer_jx_jc(duk_json_enc_ctx *js_ctx, duk_hbuffer *h);
DUK_LOCAL_DECL void duk__enc_pointer(duk_json_enc_ctx *js_ctx, void *ptr);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_LOCAL_DECL void duk__enc_bufobj(duk_json_enc_ctx *js_ctx, duk_hbufobj *h_bufobj);
#endif
#endif
#if defined(DUK_USE_JSON_STRINGIFY_FASTPATH)
DUK_LOCAL_DECL void duk__enc_buffer_json_fastpath(duk_json_enc_ctx *js_ctx, duk_hbuffer *h);
#endif
DUK_LOCAL_DECL void duk__enc_newline_indent(duk_json_enc_ctx *js_ctx, duk_uint_t depth);

/*
 *  Helper tables
 */

#if defined(DUK_USE_JSON_QUOTESTRING_FASTPATH)
DUK_LOCAL const duk_uint8_t duk__json_quotestr_lookup[256] = {
	/* 0x00 ... 0x7f: as is
	 * 0x80: escape generically
	 * 0x81: slow path
	 * 0xa0 ... 0xff: backslash + one char
	 */

	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0xe2, 0xf4, 0xee, 0x80, 0xe6, 0xf2, 0x80, 0x80,
	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
	0x20, 0x21, 0xa2, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0xdc, 0x5d, 0x5e, 0x5f,
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81
};
#else  /* DUK_USE_JSON_QUOTESTRING_FASTPATH */
DUK_LOCAL const duk_uint8_t duk__json_quotestr_esc[14] = {
	DUK_ASC_NUL, DUK_ASC_NUL, DUK_ASC_NUL, DUK_ASC_NUL,
	DUK_ASC_NUL, DUK_ASC_NUL, DUK_ASC_NUL, DUK_ASC_NUL,
	DUK_ASC_LC_B, DUK_ASC_LC_T, DUK_ASC_LC_N, DUK_ASC_NUL,
	DUK_ASC_LC_F, DUK_ASC_LC_R
};
#endif  /* DUK_USE_JSON_QUOTESTRING_FASTPATH */

#if defined(DUK_USE_JSON_DECSTRING_FASTPATH)
DUK_LOCAL const duk_uint8_t duk__json_decstr_lookup[256] = {
	/* 0x00: slow path
	 * other: as is
	 */
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x20, 0x21, 0x00, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x00, 0x5d, 0x5e, 0x5f,
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};
#endif  /* DUK_USE_JSON_DECSTRING_FASTPATH */

#if defined(DUK_USE_JSON_EATWHITE_FASTPATH)
DUK_LOCAL const duk_uint8_t duk__json_eatwhite_lookup[256] = {
	/* 0x00: finish (non-white)
	 * 0x01: continue
	 */
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif  /* DUK_USE_JSON_EATWHITE_FASTPATH */

#if defined(DUK_USE_JSON_DECNUMBER_FASTPATH)
DUK_LOCAL const duk_uint8_t duk__json_decnumber_lookup[256] = {
	/* 0x00: finish (not part of number)
	 * 0x01: continue
	 */
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x01, 0x00,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif  /* DUK_USE_JSON_DECNUMBER_FASTPATH */

/*
 *  Parsing implementation.
 *
 *  JSON lexer is now separate from duk_lexer.c because there are numerous
 *  small differences making it difficult to share the lexer.
 *
 *  The parser here works with raw bytes directly; this works because all
 *  JSON delimiters are ASCII characters.  Invalid xUTF-8 encoded values
 *  inside strings will be passed on without normalization; this is not a
 *  compliance concern because compliant inputs will always be valid
 *  CESU-8 encodings.
 */

DUK_LOCAL void duk__dec_syntax_error(duk_json_dec_ctx *js_ctx) {
	/* Shared handler to minimize parser size.  Cause will be
	 * hidden, unfortunately, but we'll have an offset which
	 * is often quite enough.
	 */
	DUK_ERROR_FMT1(js_ctx->thr, DUK_ERR_SYNTAX_ERROR, DUK_STR_FMT_INVALID_JSON,
	               (long) (js_ctx->p - js_ctx->p_start));
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__dec_eat_white(duk_json_dec_ctx *js_ctx) {
	const duk_uint8_t *p;
	duk_uint8_t t;

	p = js_ctx->p;
	for (;;) {
		DUK_ASSERT(p <= js_ctx->p_end);
		t = *p;

#if defined(DUK_USE_JSON_EATWHITE_FASTPATH)
		/* This fast path is pretty marginal in practice.
		 * XXX: candidate for removal.
		 */
		DUK_ASSERT(duk__json_eatwhite_lookup[0x00] == 0x00);  /* end-of-input breaks */
		if (duk__json_eatwhite_lookup[t] == 0) {
			break;
		}
#else  /* DUK_USE_JSON_EATWHITE_FASTPATH */
		if (!(t == 0x20 || t == 0x0a || t == 0x0d || t == 0x09)) {
			/* NUL also comes here.  Comparison order matters, 0x20
			 * is most common whitespace.
			 */
			break;
		}
#endif  /* DUK_USE_JSON_EATWHITE_FASTPATH */
		p++;
	}
	js_ctx->p = p;
}

#if defined(DUK_USE_JX)
DUK_LOCAL duk_uint8_t duk__dec_peek(duk_json_dec_ctx *js_ctx) {
	DUK_ASSERT(js_ctx->p <= js_ctx->p_end);
	return *js_ctx->p;
}
#endif

DUK_LOCAL duk_uint8_t duk__dec_get(duk_json_dec_ctx *js_ctx) {
	DUK_ASSERT(js_ctx->p <= js_ctx->p_end);
	return *js_ctx->p++;
}

DUK_LOCAL duk_uint8_t duk__dec_get_nonwhite(duk_json_dec_ctx *js_ctx) {
	duk__dec_eat_white(js_ctx);
	return duk__dec_get(js_ctx);
}

/* For JX, expressing the whole unsigned 32-bit range matters. */
DUK_LOCAL duk_uint_fast32_t duk__dec_decode_hex_escape(duk_json_dec_ctx *js_ctx, duk_small_uint_t n) {
	duk_small_uint_t i;
	duk_uint_fast32_t res = 0;
	duk_uint8_t x;
	duk_small_int_t t;

	for (i = 0; i < n; i++) {
		/* XXX: share helper from lexer; duk_lexer.c / hexval(). */

		x = duk__dec_get(js_ctx);
		DUK_DDD(DUK_DDDPRINT("decode_hex_escape: i=%ld, n=%ld, res=%ld, x=%ld",
		                     (long) i, (long) n, (long) res, (long) x));

		/* x == 0x00 (EOF) causes syntax_error */
		DUK_ASSERT(duk_hex_dectab[0] == -1);
		t = duk_hex_dectab[x & 0xff];
		if (DUK_LIKELY(t >= 0)) {
			res = (res * 16) + (duk_uint_fast32_t) t;
		} else {
			/* catches EOF and invalid digits */
			goto syntax_error;
		}
	}

	DUK_DDD(DUK_DDDPRINT("final hex decoded value: %ld", (long) res));
	return res;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
	return 0;
}

DUK_LOCAL void duk__dec_req_stridx(duk_json_dec_ctx *js_ctx, duk_small_uint_t stridx) {
	duk_hstring *h;
	const duk_uint8_t *p;
	duk_uint8_t x, y;

	/* First character has already been eaten and checked by the caller.
	 * We can scan until a NUL in stridx string because no built-in strings
	 * have internal NULs.
	 */

	DUK_ASSERT_STRIDX_VALID(stridx);
	h = DUK_HTHREAD_GET_STRING(js_ctx->thr, stridx);
	DUK_ASSERT(h != NULL);

	p = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h) + 1;
	DUK_ASSERT(*(js_ctx->p - 1) == *(p - 1));  /* first character has been matched */

	for (;;) {
		x = *p;
		if (x == 0) {
			break;
		}
		y = duk__dec_get(js_ctx);
		if (x != y) {
			/* Catches EOF of JSON input. */
			goto syntax_error;
		}
		p++;
	}

	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}

DUK_LOCAL duk_small_int_t duk__dec_string_escape(duk_json_dec_ctx *js_ctx, duk_uint8_t **ext_p) {
	duk_uint_fast32_t cp;

	/* EOF (-1) will be cast to an unsigned value first
	 * and then re-cast for the switch.  In any case, it
	 * will match the default case (syntax error).
	 */
	cp = (duk_uint_fast32_t) duk__dec_get(js_ctx);
	switch (cp) {
	case DUK_ASC_BACKSLASH: break;
	case DUK_ASC_DOUBLEQUOTE: break;
	case DUK_ASC_SLASH: break;
	case DUK_ASC_LC_T: cp = 0x09; break;
	case DUK_ASC_LC_N: cp = 0x0a; break;
	case DUK_ASC_LC_R: cp = 0x0d; break;
	case DUK_ASC_LC_F: cp = 0x0c; break;
	case DUK_ASC_LC_B: cp = 0x08; break;
	case DUK_ASC_LC_U: {
		cp = duk__dec_decode_hex_escape(js_ctx, 4);
		break;
	}
#if defined(DUK_USE_JX)
	case DUK_ASC_UC_U: {
		if (js_ctx->flag_ext_custom) {
			cp = duk__dec_decode_hex_escape(js_ctx, 8);
		} else {
			return 1;  /* syntax error */
		}
		break;
	}
	case DUK_ASC_LC_X: {
		if (js_ctx->flag_ext_custom) {
			cp = duk__dec_decode_hex_escape(js_ctx, 2);
		} else {
			return 1;  /* syntax error */
		}
		break;
	}
#endif  /* DUK_USE_JX */
	default:
		/* catches EOF (0x00) */
		return 1;  /* syntax error */
	}

	DUK_RAW_WRITEINC_XUTF8(*ext_p, cp);

	return 0;
}

DUK_LOCAL void duk__dec_string(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
	duk_uint8_t *q;

	/* '"' was eaten by caller */

	/* Note that we currently parse -bytes-, not codepoints.
	 * All non-ASCII extended UTF-8 will encode to bytes >= 0x80,
	 * so they'll simply pass through (valid UTF-8 or not).
	 */

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(js_ctx->thr, bw, DUK__JSON_DECSTR_BUFSIZE);
	q = DUK_BW_GET_PTR(js_ctx->thr, bw);

#if defined(DUK_USE_JSON_DECSTRING_FASTPATH)
	for (;;) {
		duk_small_uint_t safe;
		duk_uint8_t b, x;
		const duk_uint8_t *p;

		/* Select a safe loop count where no output checks are
		 * needed assuming we won't encounter escapes.  Input
		 * bound checks are not necessary as a NUL (guaranteed)
		 * will cause a SyntaxError before we read out of bounds.
		 */

		safe = DUK__JSON_DECSTR_CHUNKSIZE;

		/* Ensure space for 1:1 output plus one escape. */
		q = DUK_BW_ENSURE_RAW(js_ctx->thr, bw, safe + DUK_UNICODE_MAX_XUTF8_LENGTH, q);

		p = js_ctx->p;  /* temp copy, write back for next loop */
		for (;;) {
			if (safe == 0) {
				js_ctx->p = p;
				break;
			}
			safe--;

			/* End of input (NUL) goes through slow path and causes SyntaxError. */
			DUK_ASSERT(duk__json_decstr_lookup[0] == 0x00);

			b = *p++;
			x = (duk_small_int_t) duk__json_decstr_lookup[b];
			if (DUK_LIKELY(x != 0)) {
				/* Fast path, decode as is. */
				*q++ = b;
			} else if (b == DUK_ASC_DOUBLEQUOTE) {
				js_ctx->p = p;
				goto found_quote;
			} else if (b == DUK_ASC_BACKSLASH) {
				/* We've ensured space for one escaped input; then
				 * bail out and recheck (this makes escape handling
				 * quite slow but it's uncommon).
				 */
				js_ctx->p = p;
				if (duk__dec_string_escape(js_ctx, &q) != 0) {
					goto syntax_error;
				}
				break;
			} else {
				js_ctx->p = p;
				goto syntax_error;
			}
		}
	}
 found_quote:
#else  /* DUK_USE_JSON_DECSTRING_FASTPATH */
	for (;;) {
		duk_uint8_t x;

		q = DUK_BW_ENSURE_RAW(js_ctx->thr, bw, DUK_UNICODE_MAX_XUTF8_LENGTH, q);

		x = duk__dec_get(js_ctx);

		if (x == DUK_ASC_DOUBLEQUOTE) {
			break;
		} else if (x == DUK_ASC_BACKSLASH) {
			if (duk__dec_string_escape(js_ctx, &q) != 0) {
				goto syntax_error;
			}
		} else if (x < 0x20) {
			/* catches EOF (NUL) */
			goto syntax_error;
		} else {
			*q++ = (duk_uint8_t) x;
		}
	}
#endif  /* DUK_USE_JSON_DECSTRING_FASTPATH */

	DUK_BW_SETPTR_AND_COMPACT(js_ctx->thr, bw, q);
	(void) duk_buffer_to_string(thr, -1);  /* Safe if input string is safe. */

	/* [ ... str ] */

	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}

#if defined(DUK_USE_JX)
/* Decode a plain string consisting entirely of identifier characters.
 * Used to parse plain keys (e.g. "foo: 123").
 */
DUK_LOCAL void duk__dec_plain_string(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	const duk_uint8_t *p;
	duk_small_int_t x;

	/* Caller has already eaten the first char so backtrack one byte. */

	js_ctx->p--;  /* safe */
	p = js_ctx->p;

	/* Here again we parse bytes, and non-ASCII UTF-8 will cause end of
	 * parsing (which is correct except if there are non-shortest encodings).
	 * There is also no need to check explicitly for end of input buffer as
	 * the input is NUL padded and NUL will exit the parsing loop.
	 *
	 * Because no unescaping takes place, we can just scan to the end of the
	 * plain string and intern from the input buffer.
	 */

	for (;;) {
		x = *p;

		/* There is no need to check the first character specially here
		 * (i.e. reject digits): the caller only accepts valid initial
		 * characters and won't call us if the first character is a digit.
		 * This also ensures that the plain string won't be empty.
		 */

		if (!duk_unicode_is_identifier_part((duk_codepoint_t) x)) {
			break;
		}
		p++;
	}

	duk_push_lstring(thr, (const char *) js_ctx->p, (duk_size_t) (p - js_ctx->p));
	js_ctx->p = p;

	/* [ ... str ] */
}
#endif  /* DUK_USE_JX */

#if defined(DUK_USE_JX)
DUK_LOCAL void duk__dec_pointer(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	const duk_uint8_t *p;
	duk_small_int_t x;
	void *voidptr;

	/* Caller has already eaten the first character ('(') which we don't need. */

	p = js_ctx->p;

	for (;;) {
		x = *p;

		/* Assume that the native representation never contains a closing
		 * parenthesis.
		 */

		if (x == DUK_ASC_RPAREN) {
			break;
		} else if (x <= 0) {
			/* NUL term or -1 (EOF), NUL check would suffice */
			goto syntax_error;
		}
		p++;
	}

	/* There is no need to NUL delimit the sscanf() call: trailing garbage is
	 * ignored and there is always a NUL terminator which will force an error
	 * if no error is encountered before it.  It's possible that the scan
	 * would scan further than between [js_ctx->p,p[ though and we'd advance
	 * by less than the scanned value.
	 *
	 * Because pointers are platform specific, a failure to scan a pointer
	 * results in a null pointer which is a better placeholder than a missing
	 * value or an error.
	 */

	voidptr = NULL;
	(void) DUK_SSCANF((const char *) js_ctx->p, DUK_STR_FMT_PTR, &voidptr);
	duk_push_pointer(thr, voidptr);
	js_ctx->p = p + 1;  /* skip ')' */

	/* [ ... ptr ] */

	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}
#endif  /* DUK_USE_JX */

#if defined(DUK_USE_JX)
DUK_LOCAL void duk__dec_buffer(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	const duk_uint8_t *p;
	duk_uint8_t *buf;
	duk_size_t src_len;
	duk_small_int_t x;

	/* Caller has already eaten the first character ('|') which we don't need. */

	p = js_ctx->p;

	/* XXX: Would be nice to share the fast path loop from duk_hex_decode()
	 * and avoid creating a temporary buffer.  However, there are some
	 * differences which prevent trivial sharing:
	 *
	 *   - Pipe char detection
	 *   - EOF detection
	 *   - Unknown length of input and output
	 *
	 * The best approach here would be a bufwriter and a reasonaly sized
	 * safe inner loop (e.g. 64 output bytes at a time).
	 */

	for (;;) {
		x = *p;

		/* This loop intentionally does not ensure characters are valid
		 * ([0-9a-fA-F]) because the hex decode call below will do that.
		 */
		if (x == DUK_ASC_PIPE) {
			break;
		} else if (x <= 0) {
			/* NUL term or -1 (EOF), NUL check would suffice */
			goto syntax_error;
		}
		p++;
	}

	/* XXX: this is not very nice; unnecessary copy is made. */
	src_len = (duk_size_t) (p - js_ctx->p);
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, src_len);
	DUK_ASSERT(buf != NULL);
	duk_memcpy((void *) buf, (const void *) js_ctx->p, src_len);
	duk_hex_decode(thr, -1);

	js_ctx->p = p + 1;  /* skip '|' */

	/* [ ... buf ] */

	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}
#endif  /* DUK_USE_JX */

/* Parse a number, other than NaN or +/- Infinity */
DUK_LOCAL void duk__dec_number(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	const duk_uint8_t *p_start;
	const duk_uint8_t *p;
	duk_uint8_t x;
	duk_small_uint_t s2n_flags;

	DUK_DDD(DUK_DDDPRINT("parse_number"));

	p_start = js_ctx->p;

	/* First pass parse is very lenient (e.g. allows '1.2.3') and extracts a
	 * string for strict number parsing.
	 */

	p = js_ctx->p;
	for (;;) {
		x = *p;

		DUK_DDD(DUK_DDDPRINT("parse_number: p_start=%p, p=%p, p_end=%p, x=%ld",
		                     (const void *) p_start, (const void *) p,
		                     (const void *) js_ctx->p_end, (long) x));

#if defined(DUK_USE_JSON_DECNUMBER_FASTPATH)
		/* This fast path is pretty marginal in practice.
		 * XXX: candidate for removal.
		 */
		DUK_ASSERT(duk__json_decnumber_lookup[0x00] == 0x00);  /* end-of-input breaks */
		if (duk__json_decnumber_lookup[x] == 0) {
			break;
		}
#else  /* DUK_USE_JSON_DECNUMBER_FASTPATH */
		if (!((x >= DUK_ASC_0 && x <= DUK_ASC_9) ||
		      (x == DUK_ASC_PERIOD || x == DUK_ASC_LC_E ||
		       x == DUK_ASC_UC_E || x == DUK_ASC_MINUS || x == DUK_ASC_PLUS))) {
			/* Plus sign must be accepted for positive exponents
			 * (e.g. '1.5e+2').  This clause catches NULs.
			 */
			break;
		}
#endif  /* DUK_USE_JSON_DECNUMBER_FASTPATH */
		p++;  /* safe, because matched (NUL causes a break) */
	}
	js_ctx->p = p;

	DUK_ASSERT(js_ctx->p > p_start);
	duk_push_lstring(thr, (const char *) p_start, (duk_size_t) (p - p_start));

	s2n_flags = DUK_S2N_FLAG_ALLOW_EXP |
	            DUK_S2N_FLAG_ALLOW_MINUS |  /* but don't allow leading plus */
	            DUK_S2N_FLAG_ALLOW_FRAC;

	DUK_DDD(DUK_DDDPRINT("parse_number: string before parsing: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));
	duk_numconv_parse(thr, 10 /*radix*/, s2n_flags);
	if (duk_is_nan(thr, -1)) {
		duk__dec_syntax_error(js_ctx);
	}
	DUK_ASSERT(duk_is_number(thr, -1));
	DUK_DDD(DUK_DDDPRINT("parse_number: final number: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	/* [ ... num ] */
}

DUK_LOCAL void duk__dec_objarr_entry(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_require_stack(thr, DUK_JSON_DEC_REQSTACK);

	/* c recursion check */

	DUK_ASSERT_DISABLE(js_ctx->recursion_depth >= 0);  /* unsigned */
	DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
	if (js_ctx->recursion_depth >= js_ctx->recursion_limit) {
		DUK_ERROR_RANGE(thr, DUK_STR_JSONDEC_RECLIMIT);
		DUK_WO_NORETURN(return;);
	}
	js_ctx->recursion_depth++;
}

DUK_LOCAL void duk__dec_objarr_exit(duk_json_dec_ctx *js_ctx) {
	/* c recursion check */

	DUK_ASSERT(js_ctx->recursion_depth > 0);
	DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
	js_ctx->recursion_depth--;
}

DUK_LOCAL void duk__dec_object(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_int_t key_count;  /* XXX: a "first" flag would suffice */
	duk_uint8_t x;

	DUK_DDD(DUK_DDDPRINT("parse_object"));

	duk__dec_objarr_entry(js_ctx);

	duk_push_object(thr);

	/* Initial '{' has been checked and eaten by caller. */

	key_count = 0;
	for (;;) {
		x = duk__dec_get_nonwhite(js_ctx);

		DUK_DDD(DUK_DDDPRINT("parse_object: obj=%!T, x=%ld, key_count=%ld",
		                     (duk_tval *) duk_get_tval(thr, -1),
		                     (long) x, (long) key_count));

		/* handle comma and closing brace */

		if (x == DUK_ASC_COMMA && key_count > 0) {
			/* accept comma, expect new value */
			x = duk__dec_get_nonwhite(js_ctx);
		} else if (x == DUK_ASC_RCURLY) {
			/* eat closing brace */
			break;
		} else if (key_count == 0) {
			/* accept anything, expect first value (EOF will be
			 * caught by key parsing below.
			 */
			;
		} else {
			/* catches EOF (NUL) and initial comma */
			goto syntax_error;
		}

		/* parse key and value */

		if (x == DUK_ASC_DOUBLEQUOTE) {
			duk__dec_string(js_ctx);
#if defined(DUK_USE_JX)
		} else if (js_ctx->flag_ext_custom &&
		           duk_unicode_is_identifier_start((duk_codepoint_t) x)) {
			duk__dec_plain_string(js_ctx);
#endif
		} else {
			goto syntax_error;
		}

		/* [ ... obj key ] */

		x = duk__dec_get_nonwhite(js_ctx);
		if (x != DUK_ASC_COLON) {
			goto syntax_error;
		}

		duk__dec_value(js_ctx);

		/* [ ... obj key val ] */

		duk_xdef_prop_wec(thr, -3);

		/* [ ... obj ] */

		key_count++;
	}

	/* [ ... obj ] */

	DUK_DDD(DUK_DDDPRINT("parse_object: final object is %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	duk__dec_objarr_exit(js_ctx);
	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}

DUK_LOCAL void duk__dec_array(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_uarridx_t arr_idx;
	duk_uint8_t x;

	DUK_DDD(DUK_DDDPRINT("parse_array"));

	duk__dec_objarr_entry(js_ctx);

	duk_push_array(thr);

	/* Initial '[' has been checked and eaten by caller. */

	arr_idx = 0;
	for (;;) {
		x = duk__dec_get_nonwhite(js_ctx);

		DUK_DDD(DUK_DDDPRINT("parse_array: arr=%!T, x=%ld, arr_idx=%ld",
		                     (duk_tval *) duk_get_tval(thr, -1),
		                     (long) x, (long) arr_idx));

		/* handle comma and closing bracket */

		if ((x == DUK_ASC_COMMA) && (arr_idx != 0)) {
			/* accept comma, expect new value */
			;
		} else if (x == DUK_ASC_RBRACKET) {
			/* eat closing bracket */
			break;
		} else if (arr_idx == 0) {
			/* accept anything, expect first value (EOF will be
			 * caught by duk__dec_value() below.
			 */
			js_ctx->p--;  /* backtrack (safe) */
		} else {
			/* catches EOF (NUL) and initial comma */
			goto syntax_error;
		}

		/* parse value */

		duk__dec_value(js_ctx);

		/* [ ... arr val ] */

		duk_xdef_prop_index_wec(thr, -2, arr_idx);
		arr_idx++;
	}

	/* Must set 'length' explicitly when using duk_xdef_prop_xxx() to
	 * set the values.
	 */

	duk_set_length(thr, -1, arr_idx);

	/* [ ... arr ] */

	DUK_DDD(DUK_DDDPRINT("parse_array: final array is %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	duk__dec_objarr_exit(js_ctx);
	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}

DUK_LOCAL void duk__dec_value(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_uint8_t x;

	x = duk__dec_get_nonwhite(js_ctx);

	DUK_DDD(DUK_DDDPRINT("parse_value: initial x=%ld", (long) x));

	/* Note: duk__dec_req_stridx() backtracks one char */

	if (x == DUK_ASC_DOUBLEQUOTE) {
		duk__dec_string(js_ctx);
	} else if ((x >= DUK_ASC_0 && x <= DUK_ASC_9) || (x == DUK_ASC_MINUS)) {
#if defined(DUK_USE_JX)
		if (js_ctx->flag_ext_custom && x == DUK_ASC_MINUS && duk__dec_peek(js_ctx) == DUK_ASC_UC_I) {
			duk__dec_req_stridx(js_ctx, DUK_STRIDX_MINUS_INFINITY);  /* "-Infinity", '-' has been eaten */
			duk_push_number(thr, -DUK_DOUBLE_INFINITY);
		} else {
#else
		{  /* unconditional block */
#endif
			/* We already ate 'x', so backup one byte. */
			js_ctx->p--;  /* safe */
			duk__dec_number(js_ctx);
		}
	} else if (x == DUK_ASC_LC_T) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_TRUE);
		duk_push_true(thr);
	} else if (x == DUK_ASC_LC_F) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_FALSE);
		duk_push_false(thr);
	} else if (x == DUK_ASC_LC_N) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_LC_NULL);
		duk_push_null(thr);
#if defined(DUK_USE_JX)
	} else if (js_ctx->flag_ext_custom && x == DUK_ASC_LC_U) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_LC_UNDEFINED);
		duk_push_undefined(thr);
	} else if (js_ctx->flag_ext_custom && x == DUK_ASC_UC_N) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_NAN);
		duk_push_nan(thr);
	} else if (js_ctx->flag_ext_custom && x == DUK_ASC_UC_I) {
		duk__dec_req_stridx(js_ctx, DUK_STRIDX_INFINITY);
		duk_push_number(thr, DUK_DOUBLE_INFINITY);
	} else if (js_ctx->flag_ext_custom && x == DUK_ASC_LPAREN) {
		duk__dec_pointer(js_ctx);
	} else if (js_ctx->flag_ext_custom && x == DUK_ASC_PIPE) {
		duk__dec_buffer(js_ctx);
#endif
	} else if (x == DUK_ASC_LCURLY) {
		duk__dec_object(js_ctx);
	} else if (x == DUK_ASC_LBRACKET) {
		duk__dec_array(js_ctx);
	} else {
		/* catches EOF (NUL) */
		goto syntax_error;
	}

	duk__dec_eat_white(js_ctx);

	/* [ ... val ] */
	return;

 syntax_error:
	duk__dec_syntax_error(js_ctx);
	DUK_UNREACHABLE();
}

/* Recursive value reviver, implements the Walk() algorithm.  No C recursion
 * check is done here because the initial parsing step will already ensure
 * there is a reasonable limit on C recursion depth and hence object depth.
 */
DUK_LOCAL void duk__dec_reviver_walk(duk_json_dec_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_hobject *h;
	duk_uarridx_t i, arr_len;

	DUK_DDD(DUK_DDDPRINT("walk: top=%ld, holder=%!T, name=%!T",
	                     (long) duk_get_top(thr),
	                     (duk_tval *) duk_get_tval(thr, -2),
	                     (duk_tval *) duk_get_tval(thr, -1)));

	duk_dup_top(thr);
	duk_get_prop(thr, -3);  /* -> [ ... holder name val ] */

	h = duk_get_hobject(thr, -1);
	if (h != NULL) {
		if (duk_js_isarray_hobject(h)) {
			arr_len = (duk_uarridx_t) duk_get_length(thr, -1);
			for (i = 0; i < arr_len; i++) {
				/* [ ... holder name val ] */

				DUK_DDD(DUK_DDDPRINT("walk: array, top=%ld, i=%ld, arr_len=%ld, holder=%!T, name=%!T, val=%!T",
				                     (long) duk_get_top(thr), (long) i, (long) arr_len,
				                     (duk_tval *) duk_get_tval(thr, -3), (duk_tval *) duk_get_tval(thr, -2),
				                     (duk_tval *) duk_get_tval(thr, -1)));

				duk_dup_top(thr);
				(void) duk_push_uint_to_hstring(thr, (duk_uint_t) i);  /* -> [ ... holder name val val ToString(i) ] */
				duk__dec_reviver_walk(js_ctx);  /* -> [ ... holder name val new_elem ] */

				if (duk_is_undefined(thr, -1)) {
					duk_pop(thr);
					duk_del_prop_index(thr, -1, i);
				} else {
					/* XXX: duk_xdef_prop_index_wec() would be more appropriate
					 * here but it currently makes some assumptions that might
					 * not hold (e.g. that previous property is not an accessor).
					 */
					duk_put_prop_index(thr, -2, i);
				}
			}
		} else {
			/* [ ... holder name val ] */
			duk_enum(thr, -1, DUK_ENUM_OWN_PROPERTIES_ONLY /*flags*/);
			while (duk_next(thr, -1 /*enum_index*/, 0 /*get_value*/)) {
				DUK_DDD(DUK_DDDPRINT("walk: object, top=%ld, holder=%!T, name=%!T, val=%!T, enum=%!iT, obj_key=%!T",
				                     (long) duk_get_top(thr), (duk_tval *) duk_get_tval(thr, -5),
				                     (duk_tval *) duk_get_tval(thr, -4), (duk_tval *) duk_get_tval(thr, -3),
				                     (duk_tval *) duk_get_tval(thr, -2), (duk_tval *) duk_get_tval(thr, -1)));

				/* [ ... holder name val enum obj_key ] */
				duk_dup_m3(thr);
				duk_dup_m2(thr);

				/* [ ... holder name val enum obj_key val obj_key ] */
				duk__dec_reviver_walk(js_ctx);

				/* [ ... holder name val enum obj_key new_elem ] */
				if (duk_is_undefined(thr, -1)) {
					duk_pop(thr);
					duk_del_prop(thr, -3);
				} else {
					/* XXX: duk_xdef_prop_index_wec() would be more appropriate
					 * here but it currently makes some assumptions that might
					 * not hold (e.g. that previous property is not an accessor).
					 *
					 * Using duk_put_prop() works incorrectly with '__proto__'
					 * if the own property with that name has been deleted.  This
					 * does not happen normally, but a clever reviver can trigger
					 * that, see complex reviver case in: test-bug-json-parse-__proto__.js.
					 */
					duk_put_prop(thr, -4);
				}
			}
			duk_pop(thr);  /* pop enum */
		}
	}

	/* [ ... holder name val ] */

	duk_dup(thr, js_ctx->idx_reviver);
	duk_insert(thr, -4);  /* -> [ ... reviver holder name val ] */
	duk_call_method(thr, 2);  /* -> [ ... res ] */

	DUK_DDD(DUK_DDDPRINT("walk: top=%ld, result=%!T",
	                     (long) duk_get_top(thr), (duk_tval *) duk_get_tval(thr, -1)));
}

/*
 *  Stringify implementation.
 */

#define DUK__EMIT_1(js_ctx,ch)          duk__emit_1((js_ctx), (duk_uint_fast8_t) (ch))
#define DUK__EMIT_2(js_ctx,ch1,ch2)     duk__emit_2((js_ctx), (duk_uint_fast8_t) (ch1), (duk_uint_fast8_t) (ch2))
#define DUK__EMIT_HSTR(js_ctx,h)        duk__emit_hstring((js_ctx), (h))
#if defined(DUK_USE_FASTINT) || defined(DUK_USE_JX) || defined(DUK_USE_JC)
#define DUK__EMIT_CSTR(js_ctx,p)        duk__emit_cstring((js_ctx), (p))
#endif
#define DUK__EMIT_STRIDX(js_ctx,i)      duk__emit_stridx((js_ctx), (i))
#define DUK__UNEMIT_1(js_ctx)           duk__unemit_1((js_ctx))

DUK_LOCAL void duk__emit_1(duk_json_enc_ctx *js_ctx, duk_uint_fast8_t ch) {
	DUK_BW_WRITE_ENSURE_U8(js_ctx->thr, &js_ctx->bw, ch);
}

DUK_LOCAL void duk__emit_2(duk_json_enc_ctx *js_ctx, duk_uint_fast8_t ch1, duk_uint_fast8_t ch2) {
	DUK_BW_WRITE_ENSURE_U8_2(js_ctx->thr, &js_ctx->bw, ch1, ch2);
}

DUK_LOCAL void duk__emit_hstring(duk_json_enc_ctx *js_ctx, duk_hstring *h) {
	DUK_BW_WRITE_ENSURE_HSTRING(js_ctx->thr, &js_ctx->bw, h);
}

#if defined(DUK_USE_FASTINT) || defined(DUK_USE_JX) || defined(DUK_USE_JC)
DUK_LOCAL void duk__emit_cstring(duk_json_enc_ctx *js_ctx, const char *str) {
	DUK_BW_WRITE_ENSURE_CSTRING(js_ctx->thr, &js_ctx->bw, str);
}
#endif

DUK_LOCAL void duk__emit_stridx(duk_json_enc_ctx *js_ctx, duk_small_uint_t stridx) {
	duk_hstring *h;

	DUK_ASSERT_STRIDX_VALID(stridx);
	h = DUK_HTHREAD_GET_STRING(js_ctx->thr, stridx);
	DUK_ASSERT(h != NULL);

	DUK_BW_WRITE_ENSURE_HSTRING(js_ctx->thr, &js_ctx->bw, h);
}

DUK_LOCAL void duk__unemit_1(duk_json_enc_ctx *js_ctx) {
	DUK_ASSERT(DUK_BW_GET_SIZE(js_ctx->thr, &js_ctx->bw) >= 1);
	DUK_BW_ADD_PTR(js_ctx->thr, &js_ctx->bw, -1);
}

#define DUK__MKESC(nybbles,esc1,esc2)  \
	(((duk_uint_fast32_t) (nybbles)) << 16) | \
	(((duk_uint_fast32_t) (esc1)) << 8) | \
	((duk_uint_fast32_t) (esc2))

DUK_LOCAL duk_uint8_t *duk__emit_esc_auto_fast(duk_json_enc_ctx *js_ctx, duk_uint_fast32_t cp, duk_uint8_t *q) {
	duk_uint_fast32_t tmp;
	duk_small_uint_t dig;

	DUK_UNREF(js_ctx);

	/* Caller ensures space for at least DUK__JSON_MAX_ESC_LEN. */

	/* Select appropriate escape format automatically, and set 'tmp' to a
	 * value encoding both the escape format character and the nybble count:
	 *
	 *   (nybble_count << 16) | (escape_char1) | (escape_char2)
	 */

#if defined(DUK_USE_JX)
	if (DUK_LIKELY(cp < 0x100UL)) {
		if (DUK_UNLIKELY(js_ctx->flag_ext_custom != 0U)) {
			tmp = DUK__MKESC(2, DUK_ASC_BACKSLASH, DUK_ASC_LC_X);
		} else {
			tmp = DUK__MKESC(4, DUK_ASC_BACKSLASH, DUK_ASC_LC_U);
		}
	} else
#endif
	if (DUK_LIKELY(cp < 0x10000UL)) {
		tmp = DUK__MKESC(4, DUK_ASC_BACKSLASH, DUK_ASC_LC_U);
	} else {
#if defined(DUK_USE_JX)
		if (DUK_LIKELY(js_ctx->flag_ext_custom != 0U)) {
			tmp = DUK__MKESC(8, DUK_ASC_BACKSLASH, DUK_ASC_UC_U);
		} else
#endif
		{
			/* In compatible mode and standard JSON mode, output
			 * something useful for non-BMP characters.  This won't
			 * roundtrip but will still be more or less readable and
			 * more useful than an error.
			 */
			tmp = DUK__MKESC(8, DUK_ASC_UC_U, DUK_ASC_PLUS);
		}
	}

	*q++ = (duk_uint8_t) ((tmp >> 8) & 0xff);
	*q++ = (duk_uint8_t) (tmp & 0xff);

	tmp = tmp >> 16;
	while (tmp > 0) {
		tmp--;
		dig = (duk_small_uint_t) ((cp >> (4 * tmp)) & 0x0f);
		*q++ = duk_lc_digits[dig];
	}

	return q;
}

DUK_LOCAL void duk__enc_key_autoquote(duk_json_enc_ctx *js_ctx, duk_hstring *k) {
	const duk_int8_t *p, *p_start, *p_end;  /* Note: intentionally signed. */
	duk_size_t k_len;
	duk_codepoint_t cp;

	DUK_ASSERT(k != NULL);

	/* Accept ASCII strings which conform to identifier requirements
	 * as being emitted without key quotes.  Since we only accept ASCII
	 * there's no need for actual decoding: 'p' is intentionally signed
	 * so that bytes >= 0x80 extend to negative values and are rejected
	 * as invalid identifier codepoints.
	 */

	if (js_ctx->flag_avoid_key_quotes) {
		k_len = DUK_HSTRING_GET_BYTELEN(k);
		p_start = (const duk_int8_t *) DUK_HSTRING_GET_DATA(k);
		p_end = p_start + k_len;
		p = p_start;

		if (p == p_end) {
			/* Zero length string is not accepted without quotes */
			goto quote_normally;
		}
		cp = (duk_codepoint_t) (*p++);
		if (DUK_UNLIKELY(!duk_unicode_is_identifier_start(cp))) {
			goto quote_normally;
		}
		while (p < p_end) {
			cp = (duk_codepoint_t) (*p++);
			if (DUK_UNLIKELY(!duk_unicode_is_identifier_part(cp))) {
				goto quote_normally;
			}
		}

		/* This seems faster than emitting bytes one at a time and
		 * then potentially rewinding.
		 */
		DUK__EMIT_HSTR(js_ctx, k);
		return;
	}

 quote_normally:
	duk__enc_quote_string(js_ctx, k);
}

/* The Quote(value) operation: quote a string.
 *
 * Stack policy: [ ] -> [ ].
 */

DUK_LOCAL void duk__enc_quote_string(duk_json_enc_ctx *js_ctx, duk_hstring *h_str) {
	duk_hthread *thr = js_ctx->thr;
	const duk_uint8_t *p, *p_start, *p_end, *p_now, *p_tmp;
	duk_uint8_t *q;
	duk_ucodepoint_t cp;  /* typed for duk_unicode_decode_xutf8() */

	DUK_DDD(DUK_DDDPRINT("duk__enc_quote_string: h_str=%!O", (duk_heaphdr *) h_str));

	DUK_ASSERT(h_str != NULL);
	p_start = DUK_HSTRING_GET_DATA(h_str);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_str);
	p = p_start;

	DUK__EMIT_1(js_ctx, DUK_ASC_DOUBLEQUOTE);

	/* Encode string in small chunks, estimating the maximum expansion so that
	 * there's no need to ensure space while processing the chunk.
	 */

	while (p < p_end) {
		duk_size_t left, now, space;

		left = (duk_size_t) (p_end - p);
		now = (left > DUK__JSON_ENCSTR_CHUNKSIZE ?
		       DUK__JSON_ENCSTR_CHUNKSIZE : left);

		/* Maximum expansion per input byte is 6:
		 *   - invalid UTF-8 byte causes "\uXXXX" to be emitted (6/1 = 6).
		 *   - 2-byte UTF-8 encodes as "\uXXXX" (6/2 = 3).
		 *   - 4-byte UTF-8 encodes as "\Uxxxxxxxx" (10/4 = 2.5).
		 */
		space = now * 6;
		q = DUK_BW_ENSURE_GETPTR(thr, &js_ctx->bw, space);

		p_now = p + now;

		while (p < p_now) {
#if defined(DUK_USE_JSON_QUOTESTRING_FASTPATH)
			duk_uint8_t b;

			b = duk__json_quotestr_lookup[*p++];
			if (DUK_LIKELY(b < 0x80)) {
				/* Most input bytes go through here. */
				*q++ = b;
			} else if (b >= 0xa0) {
				*q++ = DUK_ASC_BACKSLASH;
				*q++ = (duk_uint8_t) (b - 0x80);
			} else if (b == 0x80) {
				cp = (duk_ucodepoint_t) (*(p - 1));
				q = duk__emit_esc_auto_fast(js_ctx, cp, q);
			} else if (b == 0x7f && js_ctx->flag_ascii_only) {
				/* 0x7F is special */
				DUK_ASSERT(b == 0x81);
				cp = (duk_ucodepoint_t) 0x7f;
				q = duk__emit_esc_auto_fast(js_ctx, cp, q);
			} else {
				DUK_ASSERT(b == 0x81);
				p--;

				/* slow path is shared */
#else  /* DUK_USE_JSON_QUOTESTRING_FASTPATH */
			cp = *p;

			if (DUK_LIKELY(cp <= 0x7f)) {
				/* ascii fast path: avoid decoding utf-8 */
				p++;
				if (cp == 0x22 || cp == 0x5c) {
					/* double quote or backslash */
					*q++ = DUK_ASC_BACKSLASH;
					*q++ = (duk_uint8_t) cp;
				} else if (cp < 0x20) {
					duk_uint_fast8_t esc_char;

					/* This approach is a bit shorter than a straight
					 * if-else-ladder and also a bit faster.
					 */
					if (cp < (sizeof(duk__json_quotestr_esc) / sizeof(duk_uint8_t)) &&
					    (esc_char = duk__json_quotestr_esc[cp]) != 0) {
						*q++ = DUK_ASC_BACKSLASH;
						*q++ = (duk_uint8_t) esc_char;
					} else {
						q = duk__emit_esc_auto_fast(js_ctx, cp, q);
					}
				} else if (cp == 0x7f && js_ctx->flag_ascii_only) {
					q = duk__emit_esc_auto_fast(js_ctx, cp, q);
				} else {
					/* any other printable -> as is */
					*q++ = (duk_uint8_t) cp;
				}
			} else {
				/* slow path is shared */
#endif  /* DUK_USE_JSON_QUOTESTRING_FASTPATH */

				/* slow path decode */

				/* If XUTF-8 decoding fails, treat the offending byte as a codepoint directly
				 * and go forward one byte.  This is of course very lossy, but allows some kind
				 * of output to be produced even for internal strings which don't conform to
				 * XUTF-8.  All standard ECMAScript strings are always CESU-8, so this behavior
				 * does not violate the ECMAScript specification.  The behavior is applied to
				 * all modes, including ECMAScript standard JSON.  Because the current XUTF-8
				 * decoding is not very strict, this behavior only really affects initial bytes
				 * and truncated codepoints.
				 *
				 * Another alternative would be to scan forwards to start of next codepoint
				 * (or end of input) and emit just one replacement codepoint.
				 */

				p_tmp = p;
				if (!duk_unicode_decode_xutf8(thr, &p, p_start, p_end, &cp)) {
					/* Decode failed. */
					cp = *p_tmp;
					p = p_tmp + 1;
				}

#if defined(DUK_USE_NONSTD_JSON_ESC_U2028_U2029)
				if (js_ctx->flag_ascii_only || cp == 0x2028 || cp == 0x2029) {
#else
				if (js_ctx->flag_ascii_only) {
#endif
					q = duk__emit_esc_auto_fast(js_ctx, cp, q);
				} else {
					/* as is */
					DUK_RAW_WRITEINC_XUTF8(q, cp);
				}
			}
		}

		DUK_BW_SET_PTR(thr, &js_ctx->bw, q);
	}

	DUK__EMIT_1(js_ctx, DUK_ASC_DOUBLEQUOTE);
}

/* Encode a double (checked by caller) from stack top.  Stack top may be
 * replaced by serialized string but is not popped (caller does that).
 */
DUK_LOCAL void duk__enc_double(duk_json_enc_ctx *js_ctx) {
	duk_hthread *thr;
	duk_tval *tv;
	duk_double_t d;
	duk_small_int_t c;
	duk_small_int_t s;
	duk_small_uint_t stridx;
	duk_small_uint_t n2s_flags;
	duk_hstring *h_str;

	DUK_ASSERT(js_ctx != NULL);
	thr = js_ctx->thr;
	DUK_ASSERT(thr != NULL);

	/* Caller must ensure 'tv' is indeed a double and not a fastint! */
	tv = DUK_GET_TVAL_NEGIDX(thr, -1);
	DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
	d = DUK_TVAL_GET_DOUBLE(tv);

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	s = (duk_small_int_t) DUK_SIGNBIT(d);
	DUK_UNREF(s);

	if (DUK_LIKELY(!(c == DUK_FP_INFINITE || c == DUK_FP_NAN))) {
		DUK_ASSERT(DUK_ISFINITE(d));

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		/* Negative zero needs special handling in JX/JC because
		 * it would otherwise serialize to '0', not '-0'.
		 */
		if (DUK_UNLIKELY(c == DUK_FP_ZERO && s != 0 &&
		                 (js_ctx->flag_ext_custom_or_compatible))) {
			duk_push_hstring_stridx(thr, DUK_STRIDX_MINUS_ZERO);  /* '-0' */
		} else
#endif  /* DUK_USE_JX || DUK_USE_JC */
		{
			n2s_flags = 0;
			/* [ ... number ] -> [ ... string ] */
			duk_numconv_stringify(thr, 10 /*radix*/, 0 /*digits*/, n2s_flags);
		}
		h_str = duk_known_hstring(thr, -1);
		DUK__EMIT_HSTR(js_ctx, h_str);
		return;
	}

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	if (!(js_ctx->flags & (DUK_JSON_FLAG_EXT_CUSTOM |
	                       DUK_JSON_FLAG_EXT_COMPATIBLE))) {
		stridx = DUK_STRIDX_LC_NULL;
	} else if (c == DUK_FP_NAN) {
		stridx = js_ctx->stridx_custom_nan;
	} else if (s == 0) {
		stridx = js_ctx->stridx_custom_posinf;
	} else {
		stridx = js_ctx->stridx_custom_neginf;
	}
#else
	stridx = DUK_STRIDX_LC_NULL;
#endif
	DUK__EMIT_STRIDX(js_ctx, stridx);
}

#if defined(DUK_USE_FASTINT)
/* Encode a fastint from duk_tval ptr, no value stack effects. */
DUK_LOCAL void duk__enc_fastint_tval(duk_json_enc_ctx *js_ctx, duk_tval *tv) {
	duk_int64_t v;

	/* Fastint range is signed 48-bit so longest value is -2^47 = -140737488355328
	 * (16 chars long), longest signed 64-bit value is -2^63 = -9223372036854775808
	 * (20 chars long).  Alloc space for 64-bit range to be safe.
	 */
	duk_uint8_t buf[20 + 1];

	/* Caller must ensure 'tv' is indeed a fastint! */
	DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv));
	v = DUK_TVAL_GET_FASTINT(tv);

	/* XXX: There are no format strings in duk_config.h yet, could add
	 * one for formatting duk_int64_t.  For now, assumes "%lld" and that
	 * "long long" type exists.  Could also rely on C99 directly but that
	 * won't work for older MSVC.
	 */
	DUK_SPRINTF((char *) buf, "%lld", (long long) v);
	DUK__EMIT_CSTR(js_ctx, (const char *) buf);
}
#endif

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
#if defined(DUK_USE_HEX_FASTPATH)
DUK_LOCAL duk_uint8_t *duk__enc_buffer_data_hex(const duk_uint8_t *src, duk_size_t src_len, duk_uint8_t *dst) {
	duk_uint8_t *q;
	duk_uint16_t *q16;
	duk_small_uint_t x;
	duk_size_t i, len_safe;
#if !defined(DUK_USE_UNALIGNED_ACCESSES_POSSIBLE)
	duk_bool_t shift_dst;
#endif

	/* Unlike in duk_hex_encode() 'dst' is not necessarily aligned by 2.
	 * For platforms where unaligned accesses are not allowed, shift 'dst'
	 * ahead by 1 byte to get alignment and then duk_memmove() the result
	 * in place.  The faster encoding loop makes up the difference.
	 * There's always space for one extra byte because a terminator always
	 * follows the hex data and that's been accounted for by the caller.
	 */

#if defined(DUK_USE_UNALIGNED_ACCESSES_POSSIBLE)
	q16 = (duk_uint16_t *) (void *) dst;
#else
	shift_dst = (duk_bool_t) (((duk_size_t) dst) & 0x01U);
	if (shift_dst) {
		DUK_DD(DUK_DDPRINT("unaligned accesses not possible, dst not aligned -> step to dst + 1"));
		q16 = (duk_uint16_t *) (void *) (dst + 1);
	} else {
		DUK_DD(DUK_DDPRINT("unaligned accesses not possible, dst is aligned"));
		q16 = (duk_uint16_t *) (void *) dst;
	}
	DUK_ASSERT((((duk_size_t) q16) & 0x01U) == 0);
#endif

	len_safe = src_len & ~0x03U;
	for (i = 0; i < len_safe; i += 4) {
		q16[0] = duk_hex_enctab[src[i]];
		q16[1] = duk_hex_enctab[src[i + 1]];
		q16[2] = duk_hex_enctab[src[i + 2]];
		q16[3] = duk_hex_enctab[src[i + 3]];
		q16 += 4;
	}
	q = (duk_uint8_t *) q16;

#if !defined(DUK_USE_UNALIGNED_ACCESSES_POSSIBLE)
	if (shift_dst) {
		q--;
		duk_memmove((void *) dst, (const void *) (dst + 1), 2 * len_safe);
		DUK_ASSERT(dst + 2 * len_safe == q);
	}
#endif

	for (; i < src_len; i++) {
		x = src[i];
		*q++ = duk_lc_digits[x >> 4];
		*q++ = duk_lc_digits[x & 0x0f];
	}

	return q;
}
#else  /* DUK_USE_HEX_FASTPATH */
DUK_LOCAL duk_uint8_t *duk__enc_buffer_data_hex(const duk_uint8_t *src, duk_size_t src_len, duk_uint8_t *dst) {
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	duk_uint8_t *q;
	duk_small_uint_t x;

	p = src;
	p_end = src + src_len;
	q = dst;
	while (p != p_end) {
		x = *p++;
		*q++ = duk_lc_digits[x >> 4];
		*q++ = duk_lc_digits[x & 0x0f];
	}

	return q;
}
#endif  /* DUK_USE_HEX_FASTPATH */

DUK_LOCAL void duk__enc_buffer_data(duk_json_enc_ctx *js_ctx, duk_uint8_t *buf_data, duk_size_t buf_len) {
	duk_hthread *thr;
	duk_uint8_t *q;
	duk_size_t space;

	thr = js_ctx->thr;

	DUK_ASSERT(js_ctx->flag_ext_custom || js_ctx->flag_ext_compatible);  /* caller checks */
	DUK_ASSERT(js_ctx->flag_ext_custom_or_compatible);

	/* Buffer values are encoded in (lowercase) hex to make the
	 * binary data readable.  Base64 or similar would be more
	 * compact but less readable, and the point of JX/JC
	 * variants is to be as useful to a programmer as possible.
	 */

	/* The #if defined() clutter here needs to handle the three
	 * cases: (1) JX+JC, (2) JX only, (3) JC only.
	 */

	/* Note: space must cater for both JX and JC. */
	space = 9 + buf_len * 2 + 2;
	DUK_ASSERT(DUK_HBUFFER_MAX_BYTELEN <= 0x7ffffffeUL);
	DUK_ASSERT((space - 2) / 2 >= buf_len);  /* overflow not possible, buffer limits */
	q = DUK_BW_ENSURE_GETPTR(thr, &js_ctx->bw, space);

#if defined(DUK_USE_JX) && defined(DUK_USE_JC)
	if (js_ctx->flag_ext_custom)
#endif
#if defined(DUK_USE_JX)
	{
		*q++ = DUK_ASC_PIPE;
		q = duk__enc_buffer_data_hex(buf_data, buf_len, q);
		*q++ = DUK_ASC_PIPE;

	}
#endif
#if defined(DUK_USE_JX) && defined(DUK_USE_JC)
	else
#endif
#if defined(DUK_USE_JC)
	{
		DUK_ASSERT(js_ctx->flag_ext_compatible);
		duk_memcpy((void *) q, (const void *) "{\"_buf\":\"", 9);  /* len: 9 */
		q += 9;
		q = duk__enc_buffer_data_hex(buf_data, buf_len, q);
		*q++ = DUK_ASC_DOUBLEQUOTE;
		*q++ = DUK_ASC_RCURLY;
	}
#endif

	DUK_BW_SET_PTR(thr, &js_ctx->bw, q);
}

DUK_LOCAL void duk__enc_buffer_jx_jc(duk_json_enc_ctx *js_ctx, duk_hbuffer *h) {
	duk__enc_buffer_data(js_ctx,
	                     (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(js_ctx->thr->heap, h),
	                     (duk_size_t) DUK_HBUFFER_GET_SIZE(h));
}
#endif  /* DUK_USE_JX || DUK_USE_JC */

#if defined(DUK_USE_JSON_STRINGIFY_FASTPATH)
DUK_LOCAL void duk__enc_buffer_json_fastpath(duk_json_enc_ctx *js_ctx, duk_hbuffer *h) {
	duk_size_t i, n;
	const duk_uint8_t *buf;
	duk_uint8_t *q;

	n = DUK_HBUFFER_GET_SIZE(h);
	if (n == 0) {
		DUK__EMIT_2(js_ctx, DUK_ASC_LCURLY, DUK_ASC_RCURLY);
		return;
	}

	DUK__EMIT_1(js_ctx, DUK_ASC_LCURLY);

	/* Maximum encoded length with 32-bit index: 1 + 10 + 2 + 3 + 1 + 1 = 18,
	 * with 64-bit index: 1 + 20 + 2 + 3 + 1 + 1 = 28.  32 has some slack.
	 *
	 * Note that because the output buffer is reallocated from time to time,
	 * side effects (such as finalizers) affecting the buffer 'h' must be
	 * disabled.  This is the case in the JSON.stringify() fast path.
	 */

	buf = (const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(js_ctx->thr->heap, h);
	if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
		for (i = 0; i < n; i++) {
			duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth + 1);
			q = DUK_BW_ENSURE_GETPTR(js_ctx->thr, &js_ctx->bw, 32);
			q += DUK_SPRINTF((char *) q, "\"%lu\": %u,", (unsigned long) i, (unsigned int) buf[i]);
			DUK_BW_SET_PTR(js_ctx->thr, &js_ctx->bw, q);
		}
	} else {
		q = DUK_BW_GET_PTR(js_ctx->thr, &js_ctx->bw);
		for (i = 0; i < n; i++) {
			q = DUK_BW_ENSURE_RAW(js_ctx->thr, &js_ctx->bw, 32, q);
			q += DUK_SPRINTF((char *) q, "\"%lu\":%u,", (unsigned long) i, (unsigned int) buf[i]);
		}
		DUK_BW_SET_PTR(js_ctx->thr, &js_ctx->bw, q);
	}
	DUK__UNEMIT_1(js_ctx);  /* eat trailing comma */

	if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
		duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth);
	}
	DUK__EMIT_1(js_ctx, DUK_ASC_RCURLY);
}
#endif  /* DUK_USE_JSON_STRINGIFY_FASTPATH */

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
DUK_LOCAL void duk__enc_pointer(duk_json_enc_ctx *js_ctx, void *ptr) {
	char buf[64];  /* XXX: how to figure correct size? */
	const char *fmt;

	DUK_ASSERT(js_ctx->flag_ext_custom || js_ctx->flag_ext_compatible);  /* caller checks */
	DUK_ASSERT(js_ctx->flag_ext_custom_or_compatible);

	duk_memzero(buf, sizeof(buf));

	/* The #if defined() clutter here needs to handle the three
	 * cases: (1) JX+JC, (2) JX only, (3) JC only.
	 */
#if defined(DUK_USE_JX) && defined(DUK_USE_JC)
	if (js_ctx->flag_ext_custom)
#endif
#if defined(DUK_USE_JX)
	{
		fmt = ptr ? "(%p)" : "(null)";
	}
#endif
#if defined(DUK_USE_JX) && defined(DUK_USE_JC)
	else
#endif
#if defined(DUK_USE_JC)
	{
		DUK_ASSERT(js_ctx->flag_ext_compatible);
		fmt = ptr ? "{\"_ptr\":\"%p\"}" : "{\"_ptr\":\"null\"}";
	}
#endif

	/* When ptr == NULL, the format argument is unused. */
	DUK_SNPRINTF(buf, sizeof(buf) - 1, fmt, ptr);  /* must not truncate */
	DUK__EMIT_CSTR(js_ctx, buf);
}
#endif  /* DUK_USE_JX || DUK_USE_JC */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
DUK_LOCAL void duk__enc_bufobj(duk_json_enc_ctx *js_ctx, duk_hbufobj *h_bufobj) {
	DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

	if (h_bufobj->buf == NULL || !DUK_HBUFOBJ_VALID_SLICE(h_bufobj)) {
		DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
	} else {
		/* Handle both full and partial slice (as long as covered). */
		duk__enc_buffer_data(js_ctx,
		                     (duk_uint8_t *) DUK_HBUFOBJ_GET_SLICE_BASE(js_ctx->thr->heap, h_bufobj),
		                     (duk_size_t) h_bufobj->length);
	}
}
#endif  /* DUK_USE_JX || DUK_USE_JC */
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/* Indent helper.  Calling code relies on js_ctx->recursion_depth also being
 * directly related to indent depth.
 */
#if defined(DUK_USE_PREFER_SIZE)
DUK_LOCAL void duk__enc_newline_indent(duk_json_enc_ctx *js_ctx, duk_uint_t depth) {
	DUK_ASSERT(js_ctx->h_gap != NULL);
	DUK_ASSERT(DUK_HSTRING_GET_BYTELEN(js_ctx->h_gap) > 0);  /* caller guarantees */

	DUK__EMIT_1(js_ctx, 0x0a);
	while (depth-- > 0) {
		DUK__EMIT_HSTR(js_ctx, js_ctx->h_gap);
	}
}
#else  /* DUK_USE_PREFER_SIZE */
DUK_LOCAL void duk__enc_newline_indent(duk_json_enc_ctx *js_ctx, duk_uint_t depth) {
	const duk_uint8_t *gap_data;
	duk_size_t gap_len;
	duk_size_t avail_bytes;   /* bytes of indent available for copying */
	duk_size_t need_bytes;    /* bytes of indent still needed */
	duk_uint8_t *p_start;
	duk_uint8_t *p;

	DUK_ASSERT(js_ctx->h_gap != NULL);
	DUK_ASSERT(DUK_HSTRING_GET_BYTELEN(js_ctx->h_gap) > 0);  /* caller guarantees */

	DUK__EMIT_1(js_ctx, 0x0a);
	if (DUK_UNLIKELY(depth == 0)) {
		return;
	}

	/* To handle deeper indents efficiently, make use of copies we've
	 * already emitted.  In effect we can emit a sequence of 1, 2, 4,
	 * 8, etc copies, and then finish the last run.  Byte counters
	 * avoid multiply with gap_len on every loop.
	 */

	gap_data = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(js_ctx->h_gap);
	gap_len = (duk_size_t) DUK_HSTRING_GET_BYTELEN(js_ctx->h_gap);
	DUK_ASSERT(gap_len > 0);

	need_bytes = gap_len * depth;
	p = DUK_BW_ENSURE_GETPTR(js_ctx->thr, &js_ctx->bw, need_bytes);
	p_start = p;

	duk_memcpy((void *) p, (const void *) gap_data, (size_t) gap_len);
	p += gap_len;
	avail_bytes = gap_len;
	DUK_ASSERT(need_bytes >= gap_len);
	need_bytes -= gap_len;

	while (need_bytes >= avail_bytes) {
		duk_memcpy((void *) p, (const void *) p_start, (size_t) avail_bytes);
		p += avail_bytes;
		need_bytes -= avail_bytes;
		avail_bytes <<= 1;
	}

	DUK_ASSERT(need_bytes < avail_bytes);  /* need_bytes may be zero */
	duk_memcpy((void *) p, (const void *) p_start, (size_t) need_bytes);
	p += need_bytes;
	/*avail_bytes += need_bytes*/

	DUK_BW_SET_PTR(js_ctx->thr, &js_ctx->bw, p);
}
#endif  /* DUK_USE_PREFER_SIZE */

/* Shared entry handling for object/array serialization. */
DUK_LOCAL void duk__enc_objarr_entry(duk_json_enc_ctx *js_ctx, duk_idx_t *entry_top) {
	duk_hthread *thr = js_ctx->thr;
	duk_hobject *h_target;
	duk_uint_fast32_t i, n;

	*entry_top = duk_get_top(thr);

	duk_require_stack(thr, DUK_JSON_ENC_REQSTACK);

	/* Loop check using a hybrid approach: a fixed-size visited[] array
	 * with overflow in a loop check object.
	 */

	h_target = duk_known_hobject(thr, -1);  /* object or array */

	n = js_ctx->recursion_depth;
	if (DUK_UNLIKELY(n > DUK_JSON_ENC_LOOPARRAY)) {
		n = DUK_JSON_ENC_LOOPARRAY;
	}
	for (i = 0; i < n; i++) {
		if (DUK_UNLIKELY(js_ctx->visiting[i] == h_target)) {
			DUK_DD(DUK_DDPRINT("slow path loop detect"));
			DUK_ERROR_TYPE(thr, DUK_STR_CYCLIC_INPUT);
			DUK_WO_NORETURN(return;);
		}
	}
	if (js_ctx->recursion_depth < DUK_JSON_ENC_LOOPARRAY) {
		js_ctx->visiting[js_ctx->recursion_depth] = h_target;
	} else {
		duk_push_sprintf(thr, DUK_STR_FMT_PTR, (void *) h_target);
		duk_dup_top(thr);  /* -> [ ... voidp voidp ] */
		if (duk_has_prop(thr, js_ctx->idx_loop)) {
			DUK_ERROR_TYPE(thr, DUK_STR_CYCLIC_INPUT);
			DUK_WO_NORETURN(return;);
		}
		duk_push_true(thr);  /* -> [ ... voidp true ] */
		duk_put_prop(thr, js_ctx->idx_loop);  /* -> [ ... ] */
	}

	/* C recursion check. */

	DUK_ASSERT_DISABLE(js_ctx->recursion_depth >= 0);  /* unsigned */
	DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
	if (js_ctx->recursion_depth >= js_ctx->recursion_limit) {
		DUK_ERROR_RANGE(thr, DUK_STR_JSONENC_RECLIMIT);
		DUK_WO_NORETURN(return;);
	}
	js_ctx->recursion_depth++;

	DUK_DDD(DUK_DDDPRINT("shared entry finished: top=%ld, loop=%!T",
	                     (long) duk_get_top(thr), (duk_tval *) duk_get_tval(thr, js_ctx->idx_loop)));
}

/* Shared exit handling for object/array serialization. */
DUK_LOCAL void duk__enc_objarr_exit(duk_json_enc_ctx *js_ctx, duk_idx_t *entry_top) {
	duk_hthread *thr = js_ctx->thr;
	duk_hobject *h_target;

	/* C recursion check. */

	DUK_ASSERT(js_ctx->recursion_depth > 0);
	DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
	js_ctx->recursion_depth--;

	/* Loop check. */

	h_target = duk_known_hobject(thr, *entry_top - 1);  /* original target at entry_top - 1 */

	if (js_ctx->recursion_depth < DUK_JSON_ENC_LOOPARRAY) {
		/* Previous entry was inside visited[], nothing to do. */
	} else {
		duk_push_sprintf(thr, DUK_STR_FMT_PTR, (void *) h_target);
		duk_del_prop(thr, js_ctx->idx_loop);  /* -> [ ... ] */
	}

	/* Restore stack top after unbalanced code paths. */
	duk_set_top(thr, *entry_top);

	DUK_DDD(DUK_DDDPRINT("shared entry finished: top=%ld, loop=%!T",
	                     (long) duk_get_top(thr), (duk_tval *) duk_get_tval(thr, js_ctx->idx_loop)));
}

/* The JO(value) operation: encode object.
 *
 * Stack policy: [ object ] -> [ object ].
 */
DUK_LOCAL void duk__enc_object(duk_json_enc_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_hstring *h_key;
	duk_idx_t entry_top;
	duk_idx_t idx_obj;
	duk_idx_t idx_keys;
	duk_bool_t emitted;
	duk_uarridx_t arr_len, i;
	duk_size_t prev_size;

	DUK_DDD(DUK_DDDPRINT("duk__enc_object: obj=%!T", (duk_tval *) duk_get_tval(thr, -1)));

	duk__enc_objarr_entry(js_ctx, &entry_top);

	idx_obj = entry_top - 1;

	if (js_ctx->idx_proplist >= 0) {
		idx_keys = js_ctx->idx_proplist;
	} else {
		/* XXX: would be nice to enumerate an object at specified index */
		duk_dup(thr, idx_obj);
		(void) duk_hobject_get_enumerated_keys(thr, DUK_ENUM_OWN_PROPERTIES_ONLY /*flags*/);  /* [ ... target ] -> [ ... target keys ] */
		idx_keys = duk_require_normalize_index(thr, -1);
		/* leave stack unbalanced on purpose */
	}

	DUK_DDD(DUK_DDDPRINT("idx_keys=%ld, h_keys=%!T",
	                     (long) idx_keys, (duk_tval *) duk_get_tval(thr, idx_keys)));

	/* Steps 8-10 have been merged to avoid a "partial" variable. */

	DUK__EMIT_1(js_ctx, DUK_ASC_LCURLY);

	/* XXX: keys is an internal object with all keys to be processed
	 * in its (gapless) array part.  Because nobody can touch the keys
	 * object, we could iterate its array part directly (keeping in mind
	 * that it can be reallocated).
	 */

	arr_len = (duk_uarridx_t) duk_get_length(thr, idx_keys);
	emitted = 0;
	for (i = 0; i < arr_len; i++) {
		duk_get_prop_index(thr, idx_keys, i);  /* -> [ ... key ] */

		DUK_DDD(DUK_DDDPRINT("object property loop: holder=%!T, key=%!T",
		                     (duk_tval *) duk_get_tval(thr, idx_obj),
		                     (duk_tval *) duk_get_tval(thr, -1)));

		h_key = duk_known_hstring(thr, -1);
		DUK_ASSERT(h_key != NULL);
		DUK_ASSERT(!DUK_HSTRING_HAS_SYMBOL(h_key));  /* proplist filtering; enum options */

		prev_size = DUK_BW_GET_SIZE(js_ctx->thr, &js_ctx->bw);
		if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
			duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth);
			duk__enc_key_autoquote(js_ctx, h_key);
			DUK__EMIT_2(js_ctx, DUK_ASC_COLON, DUK_ASC_SPACE);
		} else {
			duk__enc_key_autoquote(js_ctx, h_key);
			DUK__EMIT_1(js_ctx, DUK_ASC_COLON);
		}

		/* [ ... key ] */

		if (DUK_UNLIKELY(duk__enc_value(js_ctx, idx_obj) == 0)) {
			/* Value would yield 'undefined', so skip key altogether.
			 * Side effects have already happened.
			 */
			DUK_BW_SET_SIZE(js_ctx->thr, &js_ctx->bw, prev_size);
		} else {
			DUK__EMIT_1(js_ctx, DUK_ASC_COMMA);
			emitted = 1;
		}

		/* [ ... ] */
	}

	if (emitted) {
		DUK_ASSERT(*((duk_uint8_t *) DUK_BW_GET_PTR(js_ctx->thr, &js_ctx->bw) - 1) == DUK_ASC_COMMA);
		DUK__UNEMIT_1(js_ctx);  /* eat trailing comma */
		if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
			DUK_ASSERT(js_ctx->recursion_depth >= 1);
			duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth - 1U);
		}
	}
	DUK__EMIT_1(js_ctx, DUK_ASC_RCURLY);

	duk__enc_objarr_exit(js_ctx, &entry_top);

	DUK_ASSERT_TOP(thr, entry_top);
}

/* The JA(value) operation: encode array.
 *
 * Stack policy: [ array ] -> [ array ].
 */
DUK_LOCAL void duk__enc_array(duk_json_enc_ctx *js_ctx) {
	duk_hthread *thr = js_ctx->thr;
	duk_idx_t entry_top;
	duk_idx_t idx_arr;
	duk_bool_t emitted;
	duk_uarridx_t i, arr_len;

	DUK_DDD(DUK_DDDPRINT("duk__enc_array: array=%!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	duk__enc_objarr_entry(js_ctx, &entry_top);

	idx_arr = entry_top - 1;

	/* Steps 8-10 have been merged to avoid a "partial" variable. */

	DUK__EMIT_1(js_ctx, DUK_ASC_LBRACKET);

	arr_len = (duk_uarridx_t) duk_get_length(thr, idx_arr);
	emitted = 0;
	for (i = 0; i < arr_len; i++) {
		DUK_DDD(DUK_DDDPRINT("array entry loop: array=%!T, index=%ld, arr_len=%ld",
		                     (duk_tval *) duk_get_tval(thr, idx_arr),
		                     (long) i, (long) arr_len));

		if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
			DUK_ASSERT(js_ctx->recursion_depth >= 1);
			duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth);
		}

		(void) duk_push_uint_to_hstring(thr, (duk_uint_t) i);  /* -> [ ... key ] */

		/* [ ... key ] */

		if (DUK_UNLIKELY(duk__enc_value(js_ctx, idx_arr) == 0)) {
			/* Value would normally be omitted, replace with 'null'. */
			DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
		} else {
			;
		}

		/* [ ... ] */

		DUK__EMIT_1(js_ctx, DUK_ASC_COMMA);
		emitted = 1;
	}

	if (emitted) {
		DUK_ASSERT(*((duk_uint8_t *) DUK_BW_GET_PTR(js_ctx->thr, &js_ctx->bw) - 1) == DUK_ASC_COMMA);
		DUK__UNEMIT_1(js_ctx);  /* eat trailing comma */
		if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
			DUK_ASSERT(js_ctx->recursion_depth >= 1);
			duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth - 1U);
		}
	}
	DUK__EMIT_1(js_ctx, DUK_ASC_RBRACKET);

	duk__enc_objarr_exit(js_ctx, &entry_top);

	DUK_ASSERT_TOP(thr, entry_top);
}

/* The Str(key, holder) operation.
 *
 * Stack policy: [ ... key ] -> [ ... ]
 */
DUK_LOCAL duk_bool_t duk__enc_value(duk_json_enc_ctx *js_ctx, duk_idx_t idx_holder) {
	duk_hthread *thr = js_ctx->thr;
	duk_tval *tv;
	duk_tval *tv_holder;
	duk_tval *tv_key;
	duk_small_int_t c;

	DUK_DDD(DUK_DDDPRINT("duk__enc_value: idx_holder=%ld, holder=%!T, key=%!T",
	                     (long) idx_holder, (duk_tval *) duk_get_tval(thr, idx_holder),
	                     (duk_tval *) duk_get_tval(thr, -1)));

	tv_holder = DUK_GET_TVAL_POSIDX(thr, idx_holder);
	DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv_holder));
	tv_key = DUK_GET_TVAL_NEGIDX(thr, -1);
	DUK_ASSERT(DUK_TVAL_IS_STRING(tv_key));
	DUK_ASSERT(!DUK_HSTRING_HAS_SYMBOL(DUK_TVAL_GET_STRING(tv_key)));  /* Caller responsible. */
	(void) duk_hobject_getprop(thr, tv_holder, tv_key);

	/* -> [ ... key val ] */

	DUK_DDD(DUK_DDDPRINT("value=%!T", (duk_tval *) duk_get_tval(thr, -1)));

	/* Standard JSON checks for .toJSON() only for actual objects; for
	 * example, setting Number.prototype.toJSON and then serializing a
	 * number won't invoke the .toJSON() method.  However, lightfuncs and
	 * plain buffers mimic objects so we check for their .toJSON() method.
	 */
	if (duk_check_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT |
	                                 DUK_TYPE_MASK_LIGHTFUNC |
	                                 DUK_TYPE_MASK_BUFFER)) {
		duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_TO_JSON);
		if (duk_is_callable(thr, -1)) {  /* toJSON() can also be a lightfunc */
			DUK_DDD(DUK_DDDPRINT("value is object, has callable toJSON() -> call it"));
			/* XXX: duk_dup_unvalidated(thr, -2) etc. */
			duk_dup_m2(thr);          /* -> [ ... key val toJSON val ] */
			duk_dup_m4(thr);          /* -> [ ... key val toJSON val key ] */
			duk_call_method(thr, 1);  /* -> [ ... key val val' ] */
			duk_remove_m2(thr);       /* -> [ ... key val' ] */
		} else {
			duk_pop(thr);             /* -> [ ... key val ] */
		}
	}

	/* [ ... key val ] */

	DUK_DDD(DUK_DDDPRINT("value=%!T", (duk_tval *) duk_get_tval(thr, -1)));

	if (js_ctx->h_replacer) {
		/* XXX: Here a "slice copy" would be useful. */
		DUK_DDD(DUK_DDDPRINT("replacer is set, call replacer"));
		duk_push_hobject(thr, js_ctx->h_replacer);  /* -> [ ... key val replacer ] */
		duk_dup(thr, idx_holder);                   /* -> [ ... key val replacer holder ] */
		duk_dup_m4(thr);                            /* -> [ ... key val replacer holder key ] */
		duk_dup_m4(thr);                            /* -> [ ... key val replacer holder key val ] */
		duk_call_method(thr, 2);                    /* -> [ ... key val val' ] */
		duk_remove_m2(thr);                         /* -> [ ... key val' ] */
	}

	/* [ ... key val ] */

	DUK_DDD(DUK_DDDPRINT("value=%!T", (duk_tval *) duk_get_tval(thr, -1)));

	tv = DUK_GET_TVAL_NEGIDX(thr, -1);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;

		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (DUK_HOBJECT_IS_BUFOBJ(h) &&
		    js_ctx->flags & (DUK_JSON_FLAG_EXT_CUSTOM | DUK_JSON_FLAG_EXT_COMPATIBLE)) {
			/* With JX/JC a bufferobject gets serialized specially. */
			duk_hbufobj *h_bufobj;
			h_bufobj = (duk_hbufobj *) h;
			DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
			duk__enc_bufobj(js_ctx, h_bufobj);
			goto pop2_emitted;
		}
		/* Otherwise bufferobjects get serialized as normal objects. */
#endif  /* JX || JC */
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
		c = (duk_small_int_t) DUK_HOBJECT_GET_CLASS_NUMBER(h);
		switch (c) {
		case DUK_HOBJECT_CLASS_NUMBER: {
			DUK_DDD(DUK_DDDPRINT("value is a Number object -> coerce with ToNumber()"));
			duk_to_number_m1(thr);
			/* The coercion potentially invokes user .valueOf() and .toString()
			 * but can't result in a function value because ToPrimitive() would
			 * reject such a result: test-dev-json-stringify-coercion-1.js.
			 */
			DUK_ASSERT(!duk_is_callable(thr, -1));
			break;
		}
		case DUK_HOBJECT_CLASS_STRING: {
			DUK_DDD(DUK_DDDPRINT("value is a String object -> coerce with ToString()"));
			duk_to_string(thr, -1);
			/* Same coercion behavior as for Number. */
			DUK_ASSERT(!duk_is_callable(thr, -1));
			break;
		}
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		case DUK_HOBJECT_CLASS_POINTER:
#endif
		case DUK_HOBJECT_CLASS_BOOLEAN: {
			DUK_DDD(DUK_DDDPRINT("value is a Boolean/Buffer/Pointer object -> get internal value"));
			duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
			duk_remove_m2(thr);
			break;
		}
		default: {
			/* Normal object which doesn't get automatically coerced to a
			 * primitive value.  Functions are checked for specially.  The
			 * primitive value coercions for Number, String, Pointer, and
			 * Boolean can't result in functions so suffices to check here.
			 * Symbol objects are handled like plain objects (their primitive
			 * value is NOT looked up like for e.g. String objects).
			 */
			DUK_ASSERT(h != NULL);
			if (DUK_HOBJECT_IS_CALLABLE(h)) {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
				if (js_ctx->flags & (DUK_JSON_FLAG_EXT_CUSTOM |
				                     DUK_JSON_FLAG_EXT_COMPATIBLE)) {
					/* We only get here when doing non-standard JSON encoding */
					DUK_DDD(DUK_DDDPRINT("-> function allowed, serialize to custom format"));
					DUK_ASSERT(js_ctx->flag_ext_custom || js_ctx->flag_ext_compatible);
					DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_function);
					goto pop2_emitted;
				} else {
					DUK_DDD(DUK_DDDPRINT("-> will result in undefined (function)"));
					goto pop2_undef;
				}
#else  /* DUK_USE_JX || DUK_USE_JC */
				DUK_DDD(DUK_DDDPRINT("-> will result in undefined (function)"));
				goto pop2_undef;
#endif  /* DUK_USE_JX || DUK_USE_JC */
			}
		}
		}  /* end switch */
	}

	/* [ ... key val ] */

	DUK_DDD(DUK_DDDPRINT("value=%!T", (duk_tval *) duk_get_tval(thr, -1)));

	if (duk_check_type_mask(thr, -1, js_ctx->mask_for_undefined)) {
		/* will result in undefined */
		DUK_DDD(DUK_DDDPRINT("-> will result in undefined (type mask check)"));
		goto pop2_undef;
	}
	tv = DUK_GET_TVAL_NEGIDX(thr, -1);

	switch (DUK_TVAL_GET_TAG(tv)) {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	/* When JX/JC not in use, the type mask above will avoid this case if needed. */
	case DUK_TAG_UNDEFINED: {
		DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_undefined);
		break;
	}
#endif
	case DUK_TAG_NULL: {
		DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
		break;
	}
	case DUK_TAG_BOOLEAN: {
		DUK__EMIT_STRIDX(js_ctx, DUK_TVAL_GET_BOOLEAN(tv) ?
		                 DUK_STRIDX_TRUE : DUK_STRIDX_FALSE);
		break;
	}
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	/* When JX/JC not in use, the type mask above will avoid this case if needed. */
	case DUK_TAG_POINTER: {
		duk__enc_pointer(js_ctx, DUK_TVAL_GET_POINTER(tv));
		break;
	}
#endif  /* DUK_USE_JX || DUK_USE_JC */
	case DUK_TAG_STRING: {
		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			goto pop2_undef;
		}
		duk__enc_quote_string(js_ctx, h);
		break;
	}
	case DUK_TAG_OBJECT: {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		/* Function values are handled completely above (including
		 * coercion results):
		 */
		DUK_ASSERT(!DUK_HOBJECT_IS_CALLABLE(h));

		if (duk_js_isarray_hobject(h)) {
			duk__enc_array(js_ctx);
		} else {
			duk__enc_object(js_ctx);
		}
		break;
	}
	/* Because plain buffers mimics Uint8Array, they have enumerable
	 * index properties [0,byteLength[.  Because JSON only serializes
	 * enumerable own properties, no properties can be serialized for
	 * plain buffers (all virtual properties are non-enumerable).  However,
	 * there may be a .toJSON() method which was already handled above.
	 */
	case DUK_TAG_BUFFER: {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (js_ctx->flag_ext_custom_or_compatible) {
			duk__enc_buffer_jx_jc(js_ctx, DUK_TVAL_GET_BUFFER(tv));
			break;
		}
#endif

		/* Could implement a fastpath, but the fast path would need
		 * to handle realloc side effects correctly.
		 */
		duk_to_object(thr, -1);
		duk__enc_object(js_ctx);
		break;
	}
	case DUK_TAG_LIGHTFUNC: {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		/* We only get here when doing non-standard JSON encoding */
		DUK_ASSERT(js_ctx->flag_ext_custom || js_ctx->flag_ext_compatible);
		DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_function);
#else
		/* Standard JSON omits functions */
		DUK_UNREACHABLE();
#endif
		break;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
		/* Number serialization has a significant impact relative to
		 * other fast path code, so careful fast path for fastints.
		 */
		duk__enc_fastint_tval(js_ctx, tv);
		break;
#endif
	default: {
		/* number */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		/* XXX: A fast path for usual integers would be useful when
		 * fastint support is not enabled.
		 */
		duk__enc_double(js_ctx);
		break;
	}
	}

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
 pop2_emitted:
#endif
	duk_pop_2(thr); /* [ ... key val ] -> [ ... ] */
	return 1;  /* emitted */

 pop2_undef:
	duk_pop_2(thr);  /* [ ... key val ] -> [ ... ] */
	return 0;  /* not emitted */
}

/* E5 Section 15.12.3, main algorithm, step 4.b.ii steps 1-4. */
DUK_LOCAL duk_bool_t duk__enc_allow_into_proplist(duk_tval *tv) {
	duk_small_int_t c;

	/* XXX: some kind of external internal type checker?
	 * - type mask; symbol flag; class mask
	 */
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_STRING(tv)) {
		duk_hstring *h;
		h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			return 0;
		}
		return 1;
	} else if (DUK_TVAL_IS_NUMBER(tv)) {
		return 1;
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		c = (duk_small_int_t) DUK_HOBJECT_GET_CLASS_NUMBER(h);
		if (c == DUK_HOBJECT_CLASS_STRING || c == DUK_HOBJECT_CLASS_NUMBER) {
			return 1;
		}
	}

	return 0;
}

/*
 *  JSON.stringify() fast path
 *
 *  Otherwise supports full JSON, JX, and JC features, but bails out on any
 *  possible side effect which might change the value being serialized.  The
 *  fast path can take advantage of the fact that the value being serialized
 *  is unchanged so that we can walk directly through property tables etc.
 */

#if defined(DUK_USE_JSON_STRINGIFY_FASTPATH)
DUK_LOCAL duk_bool_t duk__json_stringify_fast_value(duk_json_enc_ctx *js_ctx, duk_tval *tv) {
	duk_uint_fast32_t i, n;

	DUK_DDD(DUK_DDDPRINT("stringify fast: %!T", tv));

	DUK_ASSERT(js_ctx != NULL);
	DUK_ASSERT(js_ctx->thr != NULL);

#if 0 /* disabled for now */
 restart_match:
#endif

	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED: {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (js_ctx->flag_ext_custom || js_ctx->flag_ext_compatible) {
			DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_undefined);
			break;
		} else {
			goto emit_undefined;
		}
#else
		goto emit_undefined;
#endif
	}
	case DUK_TAG_NULL: {
		DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
		break;
	}
	case DUK_TAG_BOOLEAN: {
		DUK__EMIT_STRIDX(js_ctx, DUK_TVAL_GET_BOOLEAN(tv) ?
		                 DUK_STRIDX_TRUE : DUK_STRIDX_FALSE);
		break;
	}
	case DUK_TAG_STRING: {
		duk_hstring *h;
		h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			goto emit_undefined;
		}
		duk__enc_quote_string(js_ctx, h);
		break;
	}
	case DUK_TAG_OBJECT: {
		duk_hobject *obj;
		duk_tval *tv_val;
		duk_bool_t emitted = 0;
		duk_uint32_t c_bit, c_all, c_array, c_unbox, c_undef,
		             c_func, c_bufobj, c_object, c_abort;

		/* For objects JSON.stringify() only looks for own, enumerable
		 * properties which is nice for the fast path here.
		 *
		 * For arrays JSON.stringify() uses [[Get]] so it will actually
		 * inherit properties during serialization!  This fast path
		 * supports gappy arrays as long as there's no actual inherited
		 * property (which might be a getter etc).
		 *
		 * Since recursion only happens for objects, we can have both
		 * recursion and loop checks here.  We use a simple, depth-limited
		 * loop check in the fast path because the object-based tracking
		 * is very slow (when tested, it accounted for 50% of fast path
		 * execution time for input data with a lot of small objects!).
		 */

		/* XXX: for real world code, could just ignore array inheritance
		 * and only look at array own properties.
		 */

		/* We rely on a few object flag / class number relationships here,
		 * assert for them.
		 */

		obj = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(obj != NULL);
		DUK_HOBJECT_ASSERT_VALID(obj);

		/* Once recursion depth is increased, exit path must decrease
		 * it (though it's OK to abort the fast path).
		 */

		DUK_ASSERT_DISABLE(js_ctx->recursion_depth >= 0);  /* unsigned */
		DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
		if (js_ctx->recursion_depth >= js_ctx->recursion_limit) {
			DUK_DD(DUK_DDPRINT("fast path recursion limit"));
			DUK_ERROR_RANGE(js_ctx->thr, DUK_STR_JSONDEC_RECLIMIT);
			DUK_WO_NORETURN(return 0;);
		}

		for (i = 0, n = (duk_uint_fast32_t) js_ctx->recursion_depth; i < n; i++) {
			if (DUK_UNLIKELY(js_ctx->visiting[i] == obj)) {
				DUK_DD(DUK_DDPRINT("fast path loop detect"));
				DUK_ERROR_TYPE(js_ctx->thr, DUK_STR_CYCLIC_INPUT);
				DUK_WO_NORETURN(return 0;);
			}
		}

		/* Guaranteed by recursion_limit setup so we don't have to
		 * check twice.
		 */
		DUK_ASSERT(js_ctx->recursion_depth < DUK_JSON_ENC_LOOPARRAY);
		js_ctx->visiting[js_ctx->recursion_depth] = obj;
		js_ctx->recursion_depth++;

		/* If object has a .toJSON() property, we can't be certain
		 * that it wouldn't mutate any value arbitrarily, so bail
		 * out of the fast path.
		 *
		 * If an object is a Proxy we also can't avoid side effects
		 * so abandon.
		 */
		/* XXX: non-callable .toJSON() doesn't need to cause an abort
		 * but does at the moment, probably not worth fixing.
		 */
		if (duk_hobject_hasprop_raw(js_ctx->thr, obj, DUK_HTHREAD_STRING_TO_JSON(js_ctx->thr)) ||
		    DUK_HOBJECT_IS_PROXY(obj)) {
			DUK_DD(DUK_DDPRINT("object has a .toJSON property or object is a Proxy, abort fast path"));
			goto abort_fastpath;
		}

		/* We could use a switch-case for the class number but it turns out
		 * a small if-else ladder on class masks is better.  The if-ladder
		 * should be in order of relevancy.
		 */

		/* XXX: move masks to js_ctx? they don't change during one
		 * fast path invocation.
		 */
		DUK_ASSERT(DUK_HOBJECT_CLASS_MAX <= 31);
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (js_ctx->flag_ext_custom_or_compatible) {
			c_all = DUK_HOBJECT_CMASK_ALL;
			c_array = DUK_HOBJECT_CMASK_ARRAY;
			c_unbox = DUK_HOBJECT_CMASK_NUMBER |
			          DUK_HOBJECT_CMASK_STRING |
			          DUK_HOBJECT_CMASK_BOOLEAN |
			          DUK_HOBJECT_CMASK_POINTER;  /* Symbols are not unboxed. */
			c_func = DUK_HOBJECT_CMASK_FUNCTION;
			c_bufobj = DUK_HOBJECT_CMASK_ALL_BUFOBJS;
			c_undef = 0;
			c_abort = 0;
			c_object = c_all & ~(c_array | c_unbox | c_func | c_bufobj | c_undef | c_abort);
		}
		else
#endif
		{
			c_all = DUK_HOBJECT_CMASK_ALL;
			c_array = DUK_HOBJECT_CMASK_ARRAY;
			c_unbox = DUK_HOBJECT_CMASK_NUMBER |
			          DUK_HOBJECT_CMASK_STRING |
			          DUK_HOBJECT_CMASK_BOOLEAN;  /* Symbols are not unboxed. */
			c_func = 0;
			c_bufobj = 0;
			c_undef = DUK_HOBJECT_CMASK_FUNCTION |
			          DUK_HOBJECT_CMASK_POINTER;
			/* As the fast path doesn't currently properly support
			 * duk_hbufobj virtual properties, abort fast path if
			 * we encounter them in plain JSON mode.
			 */
			c_abort = DUK_HOBJECT_CMASK_ALL_BUFOBJS;
			c_object = c_all & ~(c_array | c_unbox | c_func | c_bufobj | c_undef | c_abort);
		}

		c_bit = (duk_uint32_t) DUK_HOBJECT_GET_CLASS_MASK(obj);
		if (c_bit & c_object) {
			/* All other object types. */
			DUK__EMIT_1(js_ctx, DUK_ASC_LCURLY);

			/* A non-Array object should not have an array part in practice.
			 * But since it is supported internally (and perhaps used at some
			 * point), check and abandon if that's the case.
			 */
			if (DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
				DUK_DD(DUK_DDPRINT("non-Array object has array part, abort fast path"));
				goto abort_fastpath;
			}

			for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(obj); i++) {
				duk_hstring *k;
				duk_size_t prev_size;

				k = DUK_HOBJECT_E_GET_KEY(js_ctx->thr->heap, obj, i);
				if (!k) {
					continue;
				}
				if (DUK_HSTRING_HAS_ARRIDX(k)) {
					/* If an object has array index keys we would need
					 * to sort them into the ES2015 enumeration order to
					 * be consistent with the slow path.  Abort the fast
					 * path and handle in the slow path for now.
					 */
					DUK_DD(DUK_DDPRINT("property key is an array index, abort fast path"));
					goto abort_fastpath;
				}
				if (!DUK_HOBJECT_E_SLOT_IS_ENUMERABLE(js_ctx->thr->heap, obj, i)) {
					continue;
				}
				if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(js_ctx->thr->heap, obj, i)) {
					/* Getter might have arbitrary side effects,
					 * so bail out.
					 */
					DUK_DD(DUK_DDPRINT("property is an accessor, abort fast path"));
					goto abort_fastpath;
				}
				if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(k))) {
					continue;
				}

				tv_val = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(js_ctx->thr->heap, obj, i);

				prev_size = DUK_BW_GET_SIZE(js_ctx->thr, &js_ctx->bw);
				if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
					duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth);
					duk__enc_key_autoquote(js_ctx, k);
					DUK__EMIT_2(js_ctx, DUK_ASC_COLON, DUK_ASC_SPACE);
				} else {
					duk__enc_key_autoquote(js_ctx, k);
					DUK__EMIT_1(js_ctx, DUK_ASC_COLON);
				}

				if (duk__json_stringify_fast_value(js_ctx, tv_val) == 0) {
					DUK_DD(DUK_DDPRINT("prop value not supported, rewind key and colon"));
					DUK_BW_SET_SIZE(js_ctx->thr, &js_ctx->bw, prev_size);
				} else {
					DUK__EMIT_1(js_ctx, DUK_ASC_COMMA);
					emitted = 1;
				}
			}

			/* If any non-Array value had enumerable virtual own
			 * properties, they should be serialized here (actually,
			 * before the explicit properties).  Standard types don't.
			 */

			if (emitted) {
				DUK_ASSERT(*((duk_uint8_t *) DUK_BW_GET_PTR(js_ctx->thr, &js_ctx->bw) - 1) == DUK_ASC_COMMA);
				DUK__UNEMIT_1(js_ctx);  /* eat trailing comma */
				if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
					DUK_ASSERT(js_ctx->recursion_depth >= 1);
					duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth - 1U);
				}
			}
			DUK__EMIT_1(js_ctx, DUK_ASC_RCURLY);
		} else if (c_bit & c_array) {
			duk_uint_fast32_t arr_len;
			duk_uint_fast32_t asize;

			DUK__EMIT_1(js_ctx, DUK_ASC_LBRACKET);

			/* Assume arrays are dense in the fast path. */
			if (!DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
				DUK_DD(DUK_DDPRINT("Array object is sparse, abort fast path"));
				goto abort_fastpath;
			}

			arr_len = (duk_uint_fast32_t) ((duk_harray *) obj)->length;
			asize = (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(obj);
			/* Array part may be larger than 'length'; if so, iterate
			 * only up to array 'length'.  Array part may also be smaller
			 * than 'length' in some cases.
			 */
			for (i = 0; i < arr_len; i++) {
				duk_tval *tv_arrval;
				duk_hstring *h_tmp;
				duk_bool_t has_inherited;

				if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
					duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth);
				}

				if (DUK_LIKELY(i < asize)) {
					tv_arrval = DUK_HOBJECT_A_GET_VALUE_PTR(js_ctx->thr->heap, obj, i);
					if (DUK_LIKELY(!DUK_TVAL_IS_UNUSED(tv_arrval))) {
						/* Expected case: element is present. */
						if (duk__json_stringify_fast_value(js_ctx, tv_arrval) == 0) {
							DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
						}
						goto elem_done;
					}
				}

				/* Gap in array; check for inherited property,
				 * bail out if one exists.  This should be enough
				 * to support gappy arrays for all practical code.
				 */

				h_tmp = duk_push_uint_to_hstring(js_ctx->thr, (duk_uint_t) i);
				has_inherited = duk_hobject_hasprop_raw(js_ctx->thr, obj, h_tmp);
				duk_pop(js_ctx->thr);
				if (has_inherited) {
					DUK_D(DUK_DPRINT("gap in array, conflicting inherited property, abort fast path"));
					goto abort_fastpath;
				}

				/* Ordinary gap, undefined encodes to 'null' in
				 * standard JSON, but JX/JC use their form for
				 * undefined to better preserve the typing.
				 */
				DUK_D(DUK_DPRINT("gap in array, no conflicting inherited property, remain on fast path"));
#if defined(DUK_USE_JX)
				DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_undefined);
#else
				DUK__EMIT_STRIDX(js_ctx, DUK_STRIDX_LC_NULL);
#endif
				/* fall through */

			 elem_done:
				DUK__EMIT_1(js_ctx, DUK_ASC_COMMA);
				emitted = 1;
			}

			if (emitted) {
				DUK_ASSERT(*((duk_uint8_t *) DUK_BW_GET_PTR(js_ctx->thr, &js_ctx->bw) - 1) == DUK_ASC_COMMA);
				DUK__UNEMIT_1(js_ctx);  /* eat trailing comma */
				if (DUK_UNLIKELY(js_ctx->h_gap != NULL)) {
					DUK_ASSERT(js_ctx->recursion_depth >= 1);
					duk__enc_newline_indent(js_ctx, js_ctx->recursion_depth - 1U);
				}
			}
			DUK__EMIT_1(js_ctx, DUK_ASC_RBRACKET);
		} else if (c_bit & c_unbox) {
			/* Certain boxed types are required to go through
			 * automatic unboxing.  Rely on internal value being
			 * sane (to avoid infinite recursion).
			 */
			DUK_ASSERT((c_bit & DUK_HOBJECT_CMASK_SYMBOL) == 0);  /* Symbols are not unboxed. */

#if 1
			/* The code below is incorrect if .toString() or .valueOf() have
			 * have been overridden.  The correct approach would be to look up
			 * the method(s) and if they resolve to the built-in function we
			 * can safely bypass it and look up the internal value directly.
			 * Unimplemented for now, abort fast path for boxed values.
			 */
			goto abort_fastpath;
#else  /* disabled */
			/* Disabled until fixed, see above. */
			duk_tval *tv_internal;

			DUK_DD(DUK_DDPRINT("auto unboxing in fast path"));

			tv_internal = duk_hobject_get_internal_value_tval_ptr(js_ctx->thr->heap, obj);
			DUK_ASSERT(tv_internal != NULL);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv_internal) ||
			           DUK_TVAL_IS_NUMBER(tv_internal) ||
			           DUK_TVAL_IS_BOOLEAN(tv_internal) ||
			           DUK_TVAL_IS_POINTER(tv_internal));

			tv = tv_internal;
			DUK_ASSERT(js_ctx->recursion_depth > 0);
			js_ctx->recursion_depth--;  /* required to keep recursion depth correct */
			goto restart_match;
#endif  /* disabled */
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		} else if (c_bit & c_func) {
			DUK__EMIT_STRIDX(js_ctx, js_ctx->stridx_custom_function);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		} else if (c_bit & c_bufobj) {
			duk__enc_bufobj(js_ctx, (duk_hbufobj *) obj);
#endif
#endif
		} else if (c_bit & c_abort) {
			DUK_DD(DUK_DDPRINT("abort fast path for unsupported type"));
			goto abort_fastpath;
		} else {
			DUK_ASSERT((c_bit & c_undef) != 0);

			/* Must decrease recursion depth before returning. */
			DUK_ASSERT(js_ctx->recursion_depth > 0);
			DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
			js_ctx->recursion_depth--;
			goto emit_undefined;
		}

		DUK_ASSERT(js_ctx->recursion_depth > 0);
		DUK_ASSERT(js_ctx->recursion_depth <= js_ctx->recursion_limit);
		js_ctx->recursion_depth--;
		break;
	}
	case DUK_TAG_BUFFER: {
		/* Plain buffers are treated like Uint8Arrays: they have
		 * enumerable indices.  Other virtual properties are not
		 * enumerable, and inherited properties are not serialized.
		 * However, there can be a replacer (not relevant here) or
		 * a .toJSON() method (which we need to check for explicitly).
		 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		if (duk_hobject_hasprop_raw(js_ctx->thr,
		                            js_ctx->thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE],
		                            DUK_HTHREAD_STRING_TO_JSON(js_ctx->thr))) {
			DUK_DD(DUK_DDPRINT("value is a plain buffer and there's an inherited .toJSON, abort fast path"));
			goto abort_fastpath;
		}
#endif

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (js_ctx->flag_ext_custom_or_compatible) {
			duk__enc_buffer_jx_jc(js_ctx, DUK_TVAL_GET_BUFFER(tv));
			break;
		}
#endif

		/* Plain buffers mimic Uint8Arrays, and have enumerable index
		 * properties.
		 */
		duk__enc_buffer_json_fastpath(js_ctx, DUK_TVAL_GET_BUFFER(tv));
		break;
	}
	case DUK_TAG_POINTER: {
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
		if (js_ctx->flag_ext_custom_or_compatible) {
			duk__enc_pointer(js_ctx, DUK_TVAL_GET_POINTER(tv));
			break;
		} else {
			goto emit_undefined;
		}
#else
		goto emit_undefined;
#endif
	}
	case DUK_TAG_LIGHTFUNC: {
		/* A lightfunc might also inherit a .toJSON() so just bail out. */
		/* XXX: Could just lookup .toJSON() and continue in fast path,
		 * as it would almost never be defined.
		 */
		DUK_DD(DUK_DDPRINT("value is a lightfunc, abort fast path"));
		goto abort_fastpath;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT: {
		/* Number serialization has a significant impact relative to
		 * other fast path code, so careful fast path for fastints.
		 */
		duk__enc_fastint_tval(js_ctx, tv);
		break;
	}
#endif
	default: {
		/* XXX: A fast path for usual integers would be useful when
		 * fastint support is not enabled.
		 */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));

		/* XXX: Stack discipline is annoying, could be changed in numconv. */
		duk_push_tval(js_ctx->thr, tv);
		duk__enc_double(js_ctx);
		duk_pop(js_ctx->thr);

#if 0
		/* Could also rely on native sprintf(), but it will handle
		 * values like NaN, Infinity, -0, exponent notation etc in
		 * a JSON-incompatible way.
		 */
		duk_double_t d;
		char buf[64];

		DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
		d = DUK_TVAL_GET_DOUBLE(tv);
		DUK_SPRINTF(buf, "%lg", d);
		DUK__EMIT_CSTR(js_ctx, buf);
#endif
	}
	}
	return 1;  /* not undefined */

 emit_undefined:
	return 0;  /* value was undefined/unsupported */

 abort_fastpath:
	/* Error message doesn't matter: the error is ignored anyway. */
	DUK_DD(DUK_DDPRINT("aborting fast path"));
	DUK_ERROR_INTERNAL(js_ctx->thr);
	DUK_WO_NORETURN(return 0;);
}

DUK_LOCAL duk_ret_t duk__json_stringify_fast(duk_hthread *thr, void *udata) {
	duk_json_enc_ctx *js_ctx;
	duk_tval *tv;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(udata != NULL);

	js_ctx = (duk_json_enc_ctx *) udata;
	DUK_ASSERT(js_ctx != NULL);

	tv = DUK_GET_TVAL_NEGIDX(thr, -1);
	if (duk__json_stringify_fast_value(js_ctx, tv) == 0) {
		DUK_DD(DUK_DDPRINT("top level value not supported, fail fast path"));
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);  /* Error message is ignored, so doesn't matter. */
	}

	return 0;
}
#endif  /* DUK_USE_JSON_STRINGIFY_FASTPATH */

/*
 *  Top level wrappers
 */

DUK_INTERNAL
void duk_bi_json_parse_helper(duk_hthread *thr,
                              duk_idx_t idx_value,
                              duk_idx_t idx_reviver,
                              duk_small_uint_t flags) {
	duk_json_dec_ctx js_ctx_alloc;
	duk_json_dec_ctx *js_ctx = &js_ctx_alloc;
	duk_hstring *h_text;
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t entry_top = duk_get_top(thr);
#endif

	/* negative top-relative indices not allowed now */
	DUK_ASSERT(idx_value == DUK_INVALID_INDEX || idx_value >= 0);
	DUK_ASSERT(idx_reviver == DUK_INVALID_INDEX || idx_reviver >= 0);

	DUK_DDD(DUK_DDDPRINT("JSON parse start: text=%!T, reviver=%!T, flags=0x%08lx, stack_top=%ld",
	                     (duk_tval *) duk_get_tval(thr, idx_value),
	                     (duk_tval *) duk_get_tval(thr, idx_reviver),
	                     (unsigned long) flags,
	                     (long) duk_get_top(thr)));

	duk_memzero(&js_ctx_alloc, sizeof(js_ctx_alloc));
	js_ctx->thr = thr;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	/* nothing now */
#endif
	js_ctx->recursion_limit = DUK_USE_JSON_DEC_RECLIMIT;
	DUK_ASSERT(js_ctx->recursion_depth == 0);

	/* Flag handling currently assumes that flags are consistent.  This is OK
	 * because the call sites are now strictly controlled.
	 */

	js_ctx->flags = flags;
#if defined(DUK_USE_JX)
	js_ctx->flag_ext_custom = flags & DUK_JSON_FLAG_EXT_CUSTOM;
#endif
#if defined(DUK_USE_JC)
	js_ctx->flag_ext_compatible = flags & DUK_JSON_FLAG_EXT_COMPATIBLE;
#endif
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	js_ctx->flag_ext_custom_or_compatible = flags & (DUK_JSON_FLAG_EXT_CUSTOM | DUK_JSON_FLAG_EXT_COMPATIBLE);
#endif

	h_text = duk_to_hstring(thr, idx_value);  /* coerce in-place; rejects Symbols */
	DUK_ASSERT(h_text != NULL);

	/* JSON parsing code is allowed to read [p_start,p_end]: p_end is
	 * valid and points to the string NUL terminator (which is always
	 * guaranteed for duk_hstrings.
	 */
	js_ctx->p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_text);
	js_ctx->p = js_ctx->p_start;
	js_ctx->p_end = ((const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_text)) +
	                DUK_HSTRING_GET_BYTELEN(h_text);
	DUK_ASSERT(*(js_ctx->p_end) == 0x00);

	duk__dec_value(js_ctx);  /* -> [ ... value ] */

	/* Trailing whitespace has been eaten by duk__dec_value(), so if
	 * we're not at end of input here, it's a SyntaxError.
	 */

	if (js_ctx->p != js_ctx->p_end) {
		duk__dec_syntax_error(js_ctx);
	}

	if (duk_is_callable(thr, idx_reviver)) {
		DUK_DDD(DUK_DDDPRINT("applying reviver: %!T",
		                     (duk_tval *) duk_get_tval(thr, idx_reviver)));

		js_ctx->idx_reviver = idx_reviver;

		duk_push_object(thr);
		duk_dup_m2(thr);  /* -> [ ... val root val ] */
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_EMPTY_STRING);  /* default attrs ok */
		duk_push_hstring_stridx(thr, DUK_STRIDX_EMPTY_STRING);  /* -> [ ... val root "" ] */

		DUK_DDD(DUK_DDDPRINT("start reviver walk, root=%!T, name=%!T",
		                     (duk_tval *) duk_get_tval(thr, -2),
		                     (duk_tval *) duk_get_tval(thr, -1)));

		duk__dec_reviver_walk(js_ctx);  /* [ ... val root "" ] -> [ ... val val' ] */
		duk_remove_m2(thr);             /* -> [ ... val' ] */
	} else {
		DUK_DDD(DUK_DDDPRINT("reviver does not exist or is not callable: %!T",
		                     (duk_tval *) duk_get_tval(thr, idx_reviver)));
	}

	/* Final result is at stack top. */

	DUK_DDD(DUK_DDDPRINT("JSON parse end: text=%!T, reviver=%!T, flags=0x%08lx, result=%!T, stack_top=%ld",
	                     (duk_tval *) duk_get_tval(thr, idx_value),
	                     (duk_tval *) duk_get_tval(thr, idx_reviver),
	                     (unsigned long) flags,
	                     (duk_tval *) duk_get_tval(thr, -1),
	                     (long) duk_get_top(thr)));

	DUK_ASSERT(duk_get_top(thr) == entry_top + 1);
}

DUK_INTERNAL
void duk_bi_json_stringify_helper(duk_hthread *thr,
                                  duk_idx_t idx_value,
                                  duk_idx_t idx_replacer,
                                  duk_idx_t idx_space,
                                  duk_small_uint_t flags) {
	duk_json_enc_ctx js_ctx_alloc;
	duk_json_enc_ctx *js_ctx = &js_ctx_alloc;
	duk_hobject *h;
	duk_idx_t idx_holder;
	duk_idx_t entry_top;

	/* negative top-relative indices not allowed now */
	DUK_ASSERT(idx_value == DUK_INVALID_INDEX || idx_value >= 0);
	DUK_ASSERT(idx_replacer == DUK_INVALID_INDEX || idx_replacer >= 0);
	DUK_ASSERT(idx_space == DUK_INVALID_INDEX || idx_space >= 0);

	DUK_DDD(DUK_DDDPRINT("JSON stringify start: value=%!T, replacer=%!T, space=%!T, flags=0x%08lx, stack_top=%ld",
	                     (duk_tval *) duk_get_tval(thr, idx_value),
	                     (duk_tval *) duk_get_tval(thr, idx_replacer),
	                     (duk_tval *) duk_get_tval(thr, idx_space),
	                     (unsigned long) flags,
	                     (long) duk_get_top(thr)));

	entry_top = duk_get_top(thr);

	/*
	 *  Context init
	 */

	duk_memzero(&js_ctx_alloc, sizeof(js_ctx_alloc));
	js_ctx->thr = thr;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	js_ctx->h_replacer = NULL;
	js_ctx->h_gap = NULL;
#endif
	js_ctx->idx_proplist = -1;

	/* Flag handling currently assumes that flags are consistent.  This is OK
	 * because the call sites are now strictly controlled.
	 */

	js_ctx->flags = flags;
	js_ctx->flag_ascii_only = flags & DUK_JSON_FLAG_ASCII_ONLY;
	js_ctx->flag_avoid_key_quotes = flags & DUK_JSON_FLAG_AVOID_KEY_QUOTES;
#if defined(DUK_USE_JX)
	js_ctx->flag_ext_custom = flags & DUK_JSON_FLAG_EXT_CUSTOM;
#endif
#if defined(DUK_USE_JC)
	js_ctx->flag_ext_compatible = flags & DUK_JSON_FLAG_EXT_COMPATIBLE;
#endif
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	js_ctx->flag_ext_custom_or_compatible = flags & (DUK_JSON_FLAG_EXT_CUSTOM | DUK_JSON_FLAG_EXT_COMPATIBLE);
#endif

	/* The #if defined() clutter here handles the JX/JC enable/disable
	 * combinations properly.
	 */
#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	js_ctx->stridx_custom_undefined = DUK_STRIDX_LC_NULL;  /* standard JSON; array gaps */
#if defined(DUK_USE_JX)
	if (flags & DUK_JSON_FLAG_EXT_CUSTOM) {
		js_ctx->stridx_custom_undefined = DUK_STRIDX_LC_UNDEFINED;
		js_ctx->stridx_custom_nan = DUK_STRIDX_NAN;
		js_ctx->stridx_custom_neginf = DUK_STRIDX_MINUS_INFINITY;
		js_ctx->stridx_custom_posinf = DUK_STRIDX_INFINITY;
		js_ctx->stridx_custom_function =
		        (flags & DUK_JSON_FLAG_AVOID_KEY_QUOTES) ?
		                DUK_STRIDX_JSON_EXT_FUNCTION2 :
		                DUK_STRIDX_JSON_EXT_FUNCTION1;
	}
#endif  /* DUK_USE_JX */
#if defined(DUK_USE_JX) && defined(DUK_USE_JC)
	else
#endif  /* DUK_USE_JX && DUK_USE_JC */
#if defined(DUK_USE_JC)
	if (js_ctx->flags & DUK_JSON_FLAG_EXT_COMPATIBLE) {
		js_ctx->stridx_custom_undefined = DUK_STRIDX_JSON_EXT_UNDEFINED;
		js_ctx->stridx_custom_nan = DUK_STRIDX_JSON_EXT_NAN;
		js_ctx->stridx_custom_neginf = DUK_STRIDX_JSON_EXT_NEGINF;
		js_ctx->stridx_custom_posinf = DUK_STRIDX_JSON_EXT_POSINF;
		js_ctx->stridx_custom_function = DUK_STRIDX_JSON_EXT_FUNCTION1;
	}
#endif  /* DUK_USE_JC */
#endif  /* DUK_USE_JX || DUK_USE_JC */

#if defined(DUK_USE_JX) || defined(DUK_USE_JC)
	if (js_ctx->flags & (DUK_JSON_FLAG_EXT_CUSTOM |
	                     DUK_JSON_FLAG_EXT_COMPATIBLE)) {
		DUK_ASSERT(js_ctx->mask_for_undefined == 0);  /* already zero */
	}
	else
#endif  /* DUK_USE_JX || DUK_USE_JC */
	{
		/* Plain buffer is treated like ArrayBuffer and serialized.
		 * Lightfuncs are treated like objects, but JSON explicitly
		 * skips serializing Function objects so we can just reject
		 * lightfuncs here.
		 */
		js_ctx->mask_for_undefined = DUK_TYPE_MASK_UNDEFINED |
		                             DUK_TYPE_MASK_POINTER |
		                             DUK_TYPE_MASK_LIGHTFUNC;
	}

	DUK_BW_INIT_PUSHBUF(thr, &js_ctx->bw, DUK__JSON_STRINGIFY_BUFSIZE);

	js_ctx->idx_loop = duk_push_bare_object(thr);
	DUK_ASSERT(js_ctx->idx_loop >= 0);

	/* [ ... buf loop ] */

	/*
	 *  Process replacer/proplist (2nd argument to JSON.stringify)
	 */

	h = duk_get_hobject(thr, idx_replacer);
	if (h != NULL) {
		if (DUK_HOBJECT_IS_CALLABLE(h)) {
			js_ctx->h_replacer = h;
		} else if (duk_js_isarray_hobject(h)) {
			/* Here the specification requires correct array index enumeration
			 * which is a bit tricky for sparse arrays (it is handled by the
			 * enum setup code).  We now enumerate ancestors too, although the
			 * specification is not very clear on whether that is required.
			 */

			duk_uarridx_t plist_idx = 0;
			duk_small_uint_t enum_flags;

			js_ctx->idx_proplist = duk_push_array(thr);  /* XXX: array internal? */

			enum_flags = DUK_ENUM_ARRAY_INDICES_ONLY |
			             DUK_ENUM_SORT_ARRAY_INDICES;  /* expensive flag */
			duk_enum(thr, idx_replacer, enum_flags);
			while (duk_next(thr, -1 /*enum_index*/, 1 /*get_value*/)) {
				/* [ ... proplist enum_obj key val ] */
				if (duk__enc_allow_into_proplist(duk_get_tval(thr, -1))) {
					/* XXX: duplicates should be eliminated here */
					DUK_DDD(DUK_DDDPRINT("proplist enum: key=%!T, val=%!T --> accept",
					                     (duk_tval *) duk_get_tval(thr, -2),
					                     (duk_tval *) duk_get_tval(thr, -1)));
					duk_to_string(thr, -1);  /* extra coercion of strings is OK */
					duk_put_prop_index(thr, -4, plist_idx);  /* -> [ ... proplist enum_obj key ] */
					plist_idx++;
					duk_pop(thr);
				} else {
					DUK_DDD(DUK_DDDPRINT("proplist enum: key=%!T, val=%!T --> reject",
					                     (duk_tval *) duk_get_tval(thr, -2),
					                     (duk_tval *) duk_get_tval(thr, -1)));
					duk_pop_2(thr);
				}
                        }
                        duk_pop(thr);  /* pop enum */

			/* [ ... proplist ] */
		}
	}

	/* [ ... buf loop (proplist) ] */

	/*
	 *  Process space (3rd argument to JSON.stringify)
	 */

	h = duk_get_hobject(thr, idx_space);
	if (h != NULL) {
		duk_small_uint_t c = DUK_HOBJECT_GET_CLASS_NUMBER(h);
		if (c == DUK_HOBJECT_CLASS_NUMBER) {
			duk_to_number(thr, idx_space);
		} else if (c == DUK_HOBJECT_CLASS_STRING) {
			duk_to_string(thr, idx_space);
		}
	}

	if (duk_is_number(thr, idx_space)) {
		duk_small_int_t nspace;
		/* spaces[] must be static to allow initializer with old compilers like BCC */
		static const char spaces[10] = {
			DUK_ASC_SPACE, DUK_ASC_SPACE, DUK_ASC_SPACE, DUK_ASC_SPACE,
			DUK_ASC_SPACE, DUK_ASC_SPACE, DUK_ASC_SPACE, DUK_ASC_SPACE,
			DUK_ASC_SPACE, DUK_ASC_SPACE
		};  /* XXX: helper */

		/* ToInteger() coercion; NaN -> 0, infinities are clamped to 0 and 10 */
		nspace = (duk_small_int_t) duk_to_int_clamped(thr, idx_space, 0 /*minval*/, 10 /*maxval*/);
		DUK_ASSERT(nspace >= 0 && nspace <= 10);

		duk_push_lstring(thr, spaces, (duk_size_t) nspace);
		js_ctx->h_gap = duk_known_hstring(thr, -1);
		DUK_ASSERT(js_ctx->h_gap != NULL);
	} else if (duk_is_string_notsymbol(thr, idx_space)) {
		duk_dup(thr, idx_space);
		duk_substring(thr, -1, 0, 10);  /* clamp to 10 chars */
		js_ctx->h_gap = duk_known_hstring(thr, -1);
	} else {
		/* nop */
	}

	if (js_ctx->h_gap != NULL) {
		/* If gap is empty, behave as if not given at all.  Check
		 * against byte length because character length is more
		 * expensive.
		 */
		if (DUK_HSTRING_GET_BYTELEN(js_ctx->h_gap) == 0) {
			js_ctx->h_gap = NULL;
		}
	}

	/* [ ... buf loop (proplist) (gap) ] */

	/*
	 *  Fast path: assume no mutation, iterate object property tables
	 *  directly; bail out if that assumption doesn't hold.
	 */

#if defined(DUK_USE_JSON_STRINGIFY_FASTPATH)
	if (js_ctx->h_replacer == NULL &&  /* replacer is a mutation risk */
	    js_ctx->idx_proplist == -1) {  /* proplist is very rare */
		duk_int_t pcall_rc;
		duk_small_uint_t prev_ms_base_flags;

		DUK_DD(DUK_DDPRINT("try JSON.stringify() fast path"));

		/* Use recursion_limit to ensure we don't overwrite js_ctx->visiting[]
		 * array so we don't need two counter checks in the fast path.  The
		 * slow path has a much larger recursion limit which we'll use if
		 * necessary.
		 */
		DUK_ASSERT(DUK_USE_JSON_ENC_RECLIMIT >= DUK_JSON_ENC_LOOPARRAY);
		js_ctx->recursion_limit = DUK_JSON_ENC_LOOPARRAY;
		DUK_ASSERT(js_ctx->recursion_depth == 0);

		/* Execute the fast path in a protected call.  If any error is thrown,
		 * fall back to the slow path.  This includes e.g. recursion limit
		 * because the fast path has a smaller recursion limit (and simpler,
		 * limited loop detection).
		 */

		duk_dup(thr, idx_value);

		/* Must prevent finalizers which may have arbitrary side effects. */
		prev_ms_base_flags = thr->heap->ms_base_flags;
		thr->heap->ms_base_flags |=
		        DUK_MS_FLAG_NO_OBJECT_COMPACTION;      /* Avoid attempt to compact any objects. */
		thr->heap->pf_prevent_count++;                 /* Prevent finalizers. */
		DUK_ASSERT(thr->heap->pf_prevent_count != 0);  /* Wrap. */

		pcall_rc = duk_safe_call(thr, duk__json_stringify_fast, (void *) js_ctx /*udata*/, 1 /*nargs*/, 0 /*nret*/);

		DUK_ASSERT(thr->heap->pf_prevent_count > 0);
		thr->heap->pf_prevent_count--;
		thr->heap->ms_base_flags = prev_ms_base_flags;

		if (pcall_rc == DUK_EXEC_SUCCESS) {
			DUK_DD(DUK_DDPRINT("fast path successful"));
			DUK_BW_PUSH_AS_STRING(thr, &js_ctx->bw);
			goto replace_finished;
		}

		/* We come here for actual aborts (like encountering .toJSON())
		 * but also for recursion/loop errors.  Bufwriter size can be
		 * kept because we'll probably need at least as much as we've
		 * allocated so far.
		 */
		DUK_D(DUK_DPRINT("fast path failed, serialize using slow path instead"));
		DUK_BW_RESET_SIZE(thr, &js_ctx->bw);
		js_ctx->recursion_depth = 0;
	}
#endif

	/*
	 *  Create wrapper object and serialize
	 */

	idx_holder = duk_push_object(thr);
	duk_dup(thr, idx_value);
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_EMPTY_STRING);

	DUK_DDD(DUK_DDDPRINT("before: flags=0x%08lx, loop=%!T, replacer=%!O, "
	                     "proplist=%!T, gap=%!O, holder=%!T",
	                     (unsigned long) js_ctx->flags,
	                     (duk_tval *) duk_get_tval(thr, js_ctx->idx_loop),
	                     (duk_heaphdr *) js_ctx->h_replacer,
	                     (duk_tval *) (js_ctx->idx_proplist >= 0 ? duk_get_tval(thr, js_ctx->idx_proplist) : NULL),
	                     (duk_heaphdr *) js_ctx->h_gap,
	                     (duk_tval *) duk_get_tval(thr, -1)));

	/* serialize the wrapper with empty string key */

	duk_push_hstring_empty(thr);

	/* [ ... buf loop (proplist) (gap) holder "" ] */

	js_ctx->recursion_limit = DUK_USE_JSON_ENC_RECLIMIT;
	DUK_ASSERT(js_ctx->recursion_depth == 0);

	if (DUK_UNLIKELY(duk__enc_value(js_ctx, idx_holder) == 0)) {  /* [ ... holder key ] -> [ ... holder ] */
		/* Result is undefined. */
		duk_push_undefined(thr);
	} else {
		/* Convert buffer to result string. */
		DUK_BW_PUSH_AS_STRING(thr, &js_ctx->bw);
	}

	DUK_DDD(DUK_DDDPRINT("after: flags=0x%08lx, loop=%!T, replacer=%!O, "
	                     "proplist=%!T, gap=%!O, holder=%!T",
	                     (unsigned long) js_ctx->flags,
	                     (duk_tval *) duk_get_tval(thr, js_ctx->idx_loop),
	                     (duk_heaphdr *) js_ctx->h_replacer,
	                     (duk_tval *) (js_ctx->idx_proplist >= 0 ? duk_get_tval(thr, js_ctx->idx_proplist) : NULL),
	                     (duk_heaphdr *) js_ctx->h_gap,
	                     (duk_tval *) duk_get_tval(thr, idx_holder)));

	/* The stack has a variable shape here, so force it to the
	 * desired one explicitly.
	 */

#if defined(DUK_USE_JSON_STRINGIFY_FASTPATH)
 replace_finished:
#endif
	duk_replace(thr, entry_top);
	duk_set_top(thr, entry_top + 1);

	DUK_DDD(DUK_DDDPRINT("JSON stringify end: value=%!T, replacer=%!T, space=%!T, "
	                     "flags=0x%08lx, result=%!T, stack_top=%ld",
	                     (duk_tval *) duk_get_tval(thr, idx_value),
	                     (duk_tval *) duk_get_tval(thr, idx_replacer),
	                     (duk_tval *) duk_get_tval(thr, idx_space),
	                     (unsigned long) flags,
	                     (duk_tval *) duk_get_tval(thr, -1),
	                     (long) duk_get_top(thr)));

	DUK_ASSERT(duk_get_top(thr) == entry_top + 1);
}

#if defined(DUK_USE_JSON_BUILTIN)

/*
 *  Entry points
 */

DUK_INTERNAL duk_ret_t duk_bi_json_object_parse(duk_hthread *thr) {
	duk_bi_json_parse_helper(thr,
	                         0 /*idx_value*/,
	                         1 /*idx_replacer*/,
	                         0 /*flags*/);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_json_object_stringify(duk_hthread *thr) {
	duk_bi_json_stringify_helper(thr,
	                             0 /*idx_value*/,
	                             1 /*idx_replacer*/,
	                             2 /*idx_space*/,
	                             0 /*flags*/);
	return 1;
}

#endif  /* DUK_USE_JSON_BUILTIN */

#endif  /* DUK_USE_JSON_SUPPORT */

/* automatic undefs */
#undef DUK__EMIT_1
#undef DUK__EMIT_2
#undef DUK__EMIT_CSTR
#undef DUK__EMIT_HSTR
#undef DUK__EMIT_STRIDX
#undef DUK__JSON_DECSTR_BUFSIZE
#undef DUK__JSON_DECSTR_CHUNKSIZE
#undef DUK__JSON_ENCSTR_CHUNKSIZE
#undef DUK__JSON_MAX_ESC_LEN
#undef DUK__JSON_STRINGIFY_BUFSIZE
#undef DUK__MKESC
#undef DUK__UNEMIT_1
/*
 *  Math built-ins
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_MATH_BUILTIN)

/*
 *  Use static helpers which can work with math.h functions matching
 *  the following signatures. This is not portable if any of these math
 *  functions is actually a macro.
 *
 *  Typing here is intentionally 'double' wherever values interact with
 *  the standard library APIs.
 */

typedef double (*duk__one_arg_func)(double);
typedef double (*duk__two_arg_func)(double, double);

DUK_LOCAL duk_ret_t duk__math_minmax(duk_hthread *thr, duk_double_t initial, duk__two_arg_func min_max) {
	duk_idx_t n = duk_get_top(thr);
	duk_idx_t i;
	duk_double_t res = initial;
	duk_double_t t;

	/*
	 *  Note: fmax() does not match the E5 semantics.  E5 requires
	 *  that if -any- input to Math.max() is a NaN, the result is a
	 *  NaN.  fmax() will return a NaN only if -both- inputs are NaN.
	 *  Same applies to fmin().
	 *
	 *  Note: every input value must be coerced with ToNumber(), even
	 *  if we know the result will be a NaN anyway: ToNumber() may have
	 *  side effects for which even order of evaluation matters.
	 */

	for (i = 0; i < n; i++) {
		t = duk_to_number(thr, i);
		if (DUK_FPCLASSIFY(t) == DUK_FP_NAN || DUK_FPCLASSIFY(res) == DUK_FP_NAN) {
			/* Note: not normalized, but duk_push_number() will normalize */
			res = (duk_double_t) DUK_DOUBLE_NAN;
		} else {
			res = (duk_double_t) min_max(res, (double) t);
		}
	}

	duk_push_number(thr, res);
	return 1;
}

DUK_LOCAL double duk__fmin_fixed(double x, double y) {
	/* fmin() with args -0 and +0 is not guaranteed to return
	 * -0 as ECMAScript requires.
	 */
	if (duk_double_equals(x, 0.0) && duk_double_equals(y, 0.0)) {
		duk_double_union du1, du2;
		du1.d = x;
		du2.d = y;

		/* Already checked to be zero so these must hold, and allow us
		 * to check for "x is -0 or y is -0" by ORing the high parts
		 * for comparison.
		 */
		DUK_ASSERT(du1.ui[DUK_DBL_IDX_UI0] == 0 || du1.ui[DUK_DBL_IDX_UI0] == 0x80000000UL);
		DUK_ASSERT(du2.ui[DUK_DBL_IDX_UI0] == 0 || du2.ui[DUK_DBL_IDX_UI0] == 0x80000000UL);

		/* XXX: what's the safest way of creating a negative zero? */
		if ((du1.ui[DUK_DBL_IDX_UI0] | du2.ui[DUK_DBL_IDX_UI0]) != 0) {
			/* Enter here if either x or y (or both) is -0. */
			return -0.0;
		} else {
			return +0.0;
		}
	}
	return duk_double_fmin(x, y);
}

DUK_LOCAL double duk__fmax_fixed(double x, double y) {
	/* fmax() with args -0 and +0 is not guaranteed to return
	 * +0 as ECMAScript requires.
	 */
	if (duk_double_equals(x, 0.0) && duk_double_equals(y, 0.0)) {
		if (DUK_SIGNBIT(x) == 0 || DUK_SIGNBIT(y) == 0) {
			return +0.0;
		} else {
			return -0.0;
		}
	}
	return duk_double_fmax(x, y);
}

#if defined(DUK_USE_ES6)
DUK_LOCAL double duk__cbrt(double x) {
	/* cbrt() is C99.  To avoid hassling embedders with the need to provide a
	 * cube root function, we can get by with pow().  The result is not
	 * identical, but that's OK: ES2015 says it's implementation-dependent.
	 */

#if defined(DUK_CBRT)
	/* cbrt() matches ES2015 requirements. */
	return DUK_CBRT(x);
#else
	duk_small_int_t c = (duk_small_int_t) DUK_FPCLASSIFY(x);

	/* pow() does not, however. */
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE || c == DUK_FP_ZERO) {
		return x;
	}
	if (DUK_SIGNBIT(x)) {
		return -DUK_POW(-x, 1.0 / 3.0);
	} else {
		return DUK_POW(x, 1.0 / 3.0);
	}
#endif
}

DUK_LOCAL double duk__log2(double x) {
#if defined(DUK_LOG2)
	return DUK_LOG2(x);
#else
	return DUK_LOG(x) * DUK_DOUBLE_LOG2E;
#endif
}

DUK_LOCAL double duk__log10(double x) {
#if defined(DUK_LOG10)
	return DUK_LOG10(x);
#else
	return DUK_LOG(x) * DUK_DOUBLE_LOG10E;
#endif
}

DUK_LOCAL double duk__trunc(double x) {
#if defined(DUK_TRUNC)
	return DUK_TRUNC(x);
#else
	/* Handles -0 correctly: -0.0 matches 'x >= 0.0' but floor()
	 * is required to return -0 when the argument is -0.
	 */
	return x >= 0.0 ? DUK_FLOOR(x) : DUK_CEIL(x);
#endif
}
#endif  /* DUK_USE_ES6 */

DUK_LOCAL double duk__round_fixed(double x) {
	/* Numbers half-way between integers must be rounded towards +Infinity,
	 * e.g. -3.5 must be rounded to -3 (not -4).  When rounded to zero, zero
	 * sign must be set appropriately.  E5.1 Section 15.8.2.15.
	 *
	 * Note that ANSI C round() is "round to nearest integer, away from zero",
	 * which is incorrect for negative values.  Here we make do with floor().
	 */

	duk_small_int_t c = (duk_small_int_t) DUK_FPCLASSIFY(x);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE || c == DUK_FP_ZERO) {
		return x;
	}

	/*
	 *  x is finite and non-zero
	 *
	 *  -1.6 -> floor(-1.1) -> -2
	 *  -1.5 -> floor(-1.0) -> -1  (towards +Inf)
	 *  -1.4 -> floor(-0.9) -> -1
	 *  -0.5 -> -0.0               (special case)
	 *  -0.1 -> -0.0               (special case)
	 *  +0.1 -> +0.0               (special case)
	 *  +0.5 -> floor(+1.0) -> 1   (towards +Inf)
	 *  +1.4 -> floor(+1.9) -> 1
	 *  +1.5 -> floor(+2.0) -> 2   (towards +Inf)
	 *  +1.6 -> floor(+2.1) -> 2
	 */

	if (x >= -0.5 && x < 0.5) {
		/* +0.5 is handled by floor, this is on purpose */
		if (x < 0.0) {
			return -0.0;
		} else {
			return +0.0;
		}
	}

	return DUK_FLOOR(x + 0.5);
}

/* Wrappers for calling standard math library methods.  These may be required
 * on platforms where one or more of the math built-ins are defined as macros
 * or inline functions and are thus not suitable to be used as function pointers.
 */
#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
DUK_LOCAL double duk__fabs(double x) {
	return DUK_FABS(x);
}
DUK_LOCAL double duk__acos(double x) {
	return DUK_ACOS(x);
}
DUK_LOCAL double duk__asin(double x) {
	return DUK_ASIN(x);
}
DUK_LOCAL double duk__atan(double x) {
	return DUK_ATAN(x);
}
DUK_LOCAL double duk__ceil(double x) {
	return DUK_CEIL(x);
}
DUK_LOCAL double duk__cos(double x) {
	return DUK_COS(x);
}
DUK_LOCAL double duk__exp(double x) {
	return DUK_EXP(x);
}
DUK_LOCAL double duk__floor(double x) {
	return DUK_FLOOR(x);
}
DUK_LOCAL double duk__log(double x) {
	return DUK_LOG(x);
}
DUK_LOCAL double duk__sin(double x) {
	return DUK_SIN(x);
}
DUK_LOCAL double duk__sqrt(double x) {
	return DUK_SQRT(x);
}
DUK_LOCAL double duk__tan(double x) {
	return DUK_TAN(x);
}
DUK_LOCAL double duk__atan2_fixed(double x, double y) {
#if defined(DUK_USE_ATAN2_WORKAROUNDS)
	/* Specific fixes to common atan2() implementation issues:
	 * - test-bug-mingw-math-issues.js
	 */
	if (DUK_ISINF(x) && DUK_ISINF(y)) {
		if (DUK_SIGNBIT(x)) {
			if (DUK_SIGNBIT(y)) {
				return -2.356194490192345;
			} else {
				return -0.7853981633974483;
			}
		} else {
			if (DUK_SIGNBIT(y)) {
				return 2.356194490192345;
			} else {
				return 0.7853981633974483;
			}
		}
	}
#else
	/* Some ISO C assumptions. */

	DUK_ASSERT(duk_double_equals(DUK_ATAN2(DUK_DOUBLE_INFINITY, DUK_DOUBLE_INFINITY), 0.7853981633974483));
	DUK_ASSERT(duk_double_equals(DUK_ATAN2(-DUK_DOUBLE_INFINITY, DUK_DOUBLE_INFINITY), -0.7853981633974483));
	DUK_ASSERT(duk_double_equals(DUK_ATAN2(DUK_DOUBLE_INFINITY, -DUK_DOUBLE_INFINITY), 2.356194490192345));
	DUK_ASSERT(duk_double_equals(DUK_ATAN2(-DUK_DOUBLE_INFINITY, -DUK_DOUBLE_INFINITY), -2.356194490192345));
#endif

	return DUK_ATAN2(x, y);
}
#endif  /* DUK_USE_AVOID_PLATFORM_FUNCPTRS */

/* order must match constants in genbuiltins.py */
DUK_LOCAL const duk__one_arg_func duk__one_arg_funcs[] = {
#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
	duk__fabs,
	duk__acos,
	duk__asin,
	duk__atan,
	duk__ceil,
	duk__cos,
	duk__exp,
	duk__floor,
	duk__log,
	duk__round_fixed,
	duk__sin,
	duk__sqrt,
	duk__tan,
#if defined(DUK_USE_ES6)
	duk__cbrt,
	duk__log2,
	duk__log10,
	duk__trunc
#endif
#else  /* DUK_USE_AVOID_PLATFORM_FUNCPTRS */
	DUK_FABS,
	DUK_ACOS,
	DUK_ASIN,
	DUK_ATAN,
	DUK_CEIL,
	DUK_COS,
	DUK_EXP,
	DUK_FLOOR,
	DUK_LOG,
	duk__round_fixed,
	DUK_SIN,
	DUK_SQRT,
	DUK_TAN,
#if defined(DUK_USE_ES6)
	duk__cbrt,
	duk__log2,
	duk__log10,
	duk__trunc
#endif
#endif  /* DUK_USE_AVOID_PLATFORM_FUNCPTRS */
};

/* order must match constants in genbuiltins.py */
DUK_LOCAL const duk__two_arg_func duk__two_arg_funcs[] = {
#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
	duk__atan2_fixed,
	duk_js_arith_pow
#else
	duk__atan2_fixed,
	duk_js_arith_pow
#endif
};

DUK_INTERNAL duk_ret_t duk_bi_math_object_onearg_shared(duk_hthread *thr) {
	duk_small_int_t fun_idx = duk_get_current_magic(thr);
	duk__one_arg_func fun;
	duk_double_t arg1;

	DUK_ASSERT(fun_idx >= 0);
	DUK_ASSERT(fun_idx < (duk_small_int_t) (sizeof(duk__one_arg_funcs) / sizeof(duk__one_arg_func)));
	arg1 = duk_to_number(thr, 0);
	fun = duk__one_arg_funcs[fun_idx];
	duk_push_number(thr, (duk_double_t) fun((double) arg1));
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_math_object_twoarg_shared(duk_hthread *thr) {
	duk_small_int_t fun_idx = duk_get_current_magic(thr);
	duk__two_arg_func fun;
	duk_double_t arg1;
	duk_double_t arg2;

	DUK_ASSERT(fun_idx >= 0);
	DUK_ASSERT(fun_idx < (duk_small_int_t) (sizeof(duk__two_arg_funcs) / sizeof(duk__two_arg_func)));
	arg1 = duk_to_number(thr, 0);  /* explicit ordered evaluation to match coercion semantics */
	arg2 = duk_to_number(thr, 1);
	fun = duk__two_arg_funcs[fun_idx];
	duk_push_number(thr, (duk_double_t) fun((double) arg1, (double) arg2));
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_math_object_max(duk_hthread *thr) {
	return duk__math_minmax(thr, -DUK_DOUBLE_INFINITY, duk__fmax_fixed);
}

DUK_INTERNAL duk_ret_t duk_bi_math_object_min(duk_hthread *thr) {
	return duk__math_minmax(thr, DUK_DOUBLE_INFINITY, duk__fmin_fixed);
}

DUK_INTERNAL duk_ret_t duk_bi_math_object_random(duk_hthread *thr) {
	duk_push_number(thr, (duk_double_t) DUK_UTIL_GET_RANDOM_DOUBLE(thr));
	return 1;
}

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_math_object_hypot(duk_hthread *thr) {
	/*
	 *  E6 Section 20.2.2.18: Math.hypot
	 *
	 *  - If no arguments are passed, the result is +0.
	 *  - If any argument is +inf, the result is +inf.
	 *  - If any argument is -inf, the result is +inf.
	 *  - If no argument is +inf or -inf, and any argument is NaN, the result is
	 *    NaN.
	 *  - If all arguments are either +0 or -0, the result is +0.
	 */

	duk_idx_t nargs;
	duk_idx_t i;
	duk_bool_t found_nan;
	duk_double_t max;
	duk_double_t sum, summand;
	duk_double_t comp, prelim;
	duk_double_t t;

	nargs = duk_get_top(thr);

	/* Find the highest value.  Also ToNumber() coerces. */
	max = 0.0;
	found_nan = 0;
	for (i = 0; i < nargs; i++) {
		t = DUK_FABS(duk_to_number(thr, i));
		if (DUK_FPCLASSIFY(t) == DUK_FP_NAN) {
			found_nan = 1;
		} else {
			max = duk_double_fmax(max, t);
		}
	}

	/* Early return cases. */
	if (duk_double_equals(max, DUK_DOUBLE_INFINITY)) {
		duk_push_number(thr, DUK_DOUBLE_INFINITY);
		return 1;
	} else if (found_nan) {
		duk_push_number(thr, DUK_DOUBLE_NAN);
		return 1;
	} else if (duk_double_equals(max, 0.0)) {
		duk_push_number(thr, 0.0);
		/* Otherwise we'd divide by zero. */
		return 1;
	}

	/* Use Kahan summation and normalize to the highest value to minimize
	 * floating point rounding error and avoid overflow.
	 *
	 * https://en.wikipedia.org/wiki/Kahan_summation_algorithm
	 */
	sum = 0.0;
	comp = 0.0;
	for (i = 0; i < nargs; i++) {
		t = DUK_FABS(duk_get_number(thr, i)) / max;
		summand = (t * t) - comp;
		prelim = sum + summand;
		comp = (prelim - sum) - summand;
		sum = prelim;
	}

	duk_push_number(thr, (duk_double_t) DUK_SQRT(sum) * max);
	return 1;
}
#endif  /* DUK_USE_ES6 */

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_math_object_sign(duk_hthread *thr) {
	duk_double_t d;

	d = duk_to_number(thr, 0);
	if (duk_double_is_nan(d)) {
		DUK_ASSERT(duk_is_nan(thr, -1));
		return 1;  /* NaN input -> return NaN */
	}
	if (duk_double_equals(d, 0.0)) {
		/* Zero sign kept, i.e. -0 -> -0, +0 -> +0. */
		return 1;
	}
	duk_push_int(thr, (d > 0.0 ? 1 : -1));
	return 1;
}
#endif  /* DUK_USE_ES6 */

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_math_object_clz32(duk_hthread *thr) {
	duk_uint32_t x;
	duk_small_uint_t i;

#if defined(DUK_USE_PREFER_SIZE)
	duk_uint32_t mask;

	x = duk_to_uint32(thr, 0);
	for (i = 0, mask = 0x80000000UL; mask != 0; mask >>= 1) {
		if (x & mask) {
			break;
		}
		i++;
	}
	DUK_ASSERT(i <= 32);
	duk_push_uint(thr, i);
	return 1;
#else  /* DUK_USE_PREFER_SIZE */
	i = 0;
	x = duk_to_uint32(thr, 0);
	if (x & 0xffff0000UL) {
		x >>= 16;
	} else {
		i += 16;
	}
	if (x & 0x0000ff00UL) {
		x >>= 8;
	} else {
		i += 8;
	}
	if (x & 0x000000f0UL) {
		x >>= 4;
	} else {
		i += 4;
	}
	if (x & 0x0000000cUL) {
		x >>= 2;
	} else {
		i += 2;
	}
	if (x & 0x00000002UL) {
		x >>= 1;
	} else {
		i += 1;
	}
	if (x & 0x00000001UL) {
		;
	} else {
		i += 1;
	}
	DUK_ASSERT(i <= 32);
	duk_push_uint(thr, i);
	return 1;
#endif  /* DUK_USE_PREFER_SIZE */
}
#endif  /* DUK_USE_ES6 */

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_math_object_imul(duk_hthread *thr) {
	duk_uint32_t x, y, z;

	x = duk_to_uint32(thr, 0);
	y = duk_to_uint32(thr, 1);
	z = x * y;

	/* While arguments are ToUint32() coerced and the multiplication
	 * is unsigned as such, the final result is curiously interpreted
	 * as a signed 32-bit value.
	 */
	duk_push_i32(thr, (duk_int32_t) z);
	return 1;
}
#endif  /* DUK_USE_ES6 */

#endif  /* DUK_USE_MATH_BUILTIN */
/*
 *  Number built-ins
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_NUMBER_BUILTIN)

DUK_LOCAL duk_double_t duk__push_this_number_plain(duk_hthread *thr) {
	duk_hobject *h;

	/* Number built-in accepts a plain number or a Number object (whose
	 * internal value is operated on).  Other types cause TypeError.
	 */

	duk_push_this(thr);
	if (duk_is_number(thr, -1)) {
		DUK_DDD(DUK_DDDPRINT("plain number value: %!T", (duk_tval *) duk_get_tval(thr, -1)));
		goto done;
	}
	h = duk_get_hobject(thr, -1);
	if (!h ||
	    (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_NUMBER)) {
		DUK_DDD(DUK_DDDPRINT("unacceptable this value: %!T", (duk_tval *) duk_get_tval(thr, -1)));
		DUK_ERROR_TYPE(thr, "number expected");
		DUK_WO_NORETURN(return 0.0;);
	}
	duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
	DUK_ASSERT(duk_is_number(thr, -1));
	DUK_DDD(DUK_DDDPRINT("number object: %!T, internal value: %!T",
	                     (duk_tval *) duk_get_tval(thr, -2), (duk_tval *) duk_get_tval(thr, -1)));
	duk_remove_m2(thr);

 done:
	return duk_get_number(thr, -1);
}

DUK_INTERNAL duk_ret_t duk_bi_number_constructor(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_hobject *h_this;

	/*
	 *  The Number constructor uses ToNumber(arg) for number coercion
	 *  (coercing an undefined argument to NaN).  However, if the
	 *  argument is not given at all, +0 must be used instead.  To do
	 *  this, a vararg function is used.
	 */

	nargs = duk_get_top(thr);
	if (nargs == 0) {
		duk_push_int(thr, 0);
	}
	duk_to_number(thr, 0);
	duk_set_top(thr, 1);
	DUK_ASSERT_TOP(thr, 1);

	if (!duk_is_constructor_call(thr)) {
		return 1;
	}

	/*
	 *  E5 Section 15.7.2.1 requires that the constructed object
	 *  must have the original Number.prototype as its internal
	 *  prototype.  However, since Number.prototype is non-writable
	 *  and non-configurable, this doesn't have to be enforced here:
	 *  The default object (bound to 'this') is OK, though we have
	 *  to change its class.
	 *
	 *  Internal value set to ToNumber(arg) or +0; if no arg given,
	 *  ToNumber(undefined) = NaN, so special treatment is needed
	 *  (above).  String internal value is immutable.
	 */

	/* XXX: helper */
	duk_push_this(thr);
	h_this = duk_known_hobject(thr, -1);
	DUK_HOBJECT_SET_CLASS_NUMBER(h_this, DUK_HOBJECT_CLASS_NUMBER);

	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_this) == thr->builtins[DUK_BIDX_NUMBER_PROTOTYPE]);
	DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(h_this) == DUK_HOBJECT_CLASS_NUMBER);
	DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(h_this));

	duk_dup_0(thr);  /* -> [ val obj val ] */
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);
	return 0;  /* no return value -> don't replace created value */
}

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_value_of(duk_hthread *thr) {
	(void) duk__push_this_number_plain(thr);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_string(duk_hthread *thr) {
	duk_small_int_t radix;
	duk_small_uint_t n2s_flags;

	(void) duk__push_this_number_plain(thr);
	if (duk_is_undefined(thr, 0)) {
		radix = 10;
	} else {
		radix = (duk_small_int_t) duk_to_int_check_range(thr, 0, 2, 36);
	}
	DUK_DDD(DUK_DDDPRINT("radix=%ld", (long) radix));

	n2s_flags = 0;

	duk_numconv_stringify(thr,
	                      radix /*radix*/,
	                      0 /*digits*/,
	                      n2s_flags /*flags*/);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_locale_string(duk_hthread *thr) {
	/* XXX: just use toString() for now; permitted although not recommended.
	 * nargs==1, so radix is passed to toString().
	 */
	return duk_bi_number_prototype_to_string(thr);
}

/*
 *  toFixed(), toExponential(), toPrecision()
 */

/* XXX: shared helper for toFixed(), toExponential(), toPrecision()? */

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_fixed(duk_hthread *thr) {
	duk_small_int_t frac_digits;
	duk_double_t d;
	duk_small_int_t c;
	duk_small_uint_t n2s_flags;

	/* In ES5.1 frac_digits is coerced first; in ES2015 the 'this number
	 * value' check is done first.
	 */
	d = duk__push_this_number_plain(thr);
	frac_digits = (duk_small_int_t) duk_to_int_check_range(thr, 0, 0, 20);

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	if (d >= 1.0e21 || d <= -1.0e21) {
		goto use_to_string;
	}

	n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
	            DUK_N2S_FLAG_FRACTION_DIGITS;

	duk_numconv_stringify(thr,
	                      10 /*radix*/,
	                      frac_digits /*digits*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	DUK_ASSERT_TOP(thr, 2);
	duk_to_string(thr, -1);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_exponential(duk_hthread *thr) {
	duk_bool_t frac_undefined;
	duk_small_int_t frac_digits;
	duk_double_t d;
	duk_small_int_t c;
	duk_small_uint_t n2s_flags;

	d = duk__push_this_number_plain(thr);

	frac_undefined = duk_is_undefined(thr, 0);
	duk_to_int(thr, 0);  /* for side effects */

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	frac_digits = (duk_small_int_t) duk_to_int_check_range(thr, 0, 0, 20);

	n2s_flags = DUK_N2S_FLAG_FORCE_EXP |
	           (frac_undefined ? 0 : DUK_N2S_FLAG_FIXED_FORMAT);

	duk_numconv_stringify(thr,
	                      10 /*radix*/,
	                      frac_digits + 1 /*leading digit + fractions*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	DUK_ASSERT_TOP(thr, 2);
	duk_to_string(thr, -1);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_precision(duk_hthread *thr) {
	/* The specification has quite awkward order of coercion and
	 * checks for toPrecision().  The operations below are a bit
	 * reordered, within constraints of observable side effects.
	 */

	duk_double_t d;
	duk_small_int_t prec;
	duk_small_int_t c;
	duk_small_uint_t n2s_flags;

	DUK_ASSERT_TOP(thr, 1);

	d = duk__push_this_number_plain(thr);
	if (duk_is_undefined(thr, 0)) {
		goto use_to_string;
	}
	DUK_ASSERT_TOP(thr, 2);

	duk_to_int(thr, 0);  /* for side effects */

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	prec = (duk_small_int_t) duk_to_int_check_range(thr, 0, 1, 21);

	n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
	            DUK_N2S_FLAG_NO_ZERO_PAD;

	duk_numconv_stringify(thr,
	                      10 /*radix*/,
	                      prec /*digits*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	/* Used when precision is undefined; also used for NaN (-> "NaN"),
	 * and +/- infinity (-> "Infinity", "-Infinity").
	 */

	DUK_ASSERT_TOP(thr, 2);
	duk_to_string(thr, -1);
	return 1;
}

/*
 *  ES2015 isFinite() etc
 */

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_number_check_shared(duk_hthread *thr) {
	duk_int_t magic;
	duk_bool_t ret = 0;

	if (duk_is_number(thr, 0)) {
		duk_double_t d;

		magic = duk_get_current_magic(thr);
		d = duk_get_number(thr, 0);

		switch (magic) {
		case 0:  /* isFinite() */
			ret = duk_double_is_finite(d);
			break;
		case 1:  /* isInteger() */
			ret = duk_double_is_integer(d);
			break;
		case 2:  /* isNaN() */
			ret = duk_double_is_nan(d);
			break;
		default:  /* isSafeInteger() */
			DUK_ASSERT(magic == 3);
			ret = duk_double_is_safe_integer(d);
		}
	}

	duk_push_boolean(thr, ret);
	return 1;
}
#endif  /* DUK_USE_ES6 */

#endif  /* DUK_USE_NUMBER_BUILTIN */
/*
 *  Object built-ins
 */

/* #include duk_internal.h -> already included */

/* Needed even when Object built-in disabled. */
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_to_string(duk_hthread *thr) {
	duk_tval *tv;

	tv = DUK_HTHREAD_THIS_PTR(thr);
	duk_push_class_string_tval(thr, tv, 0 /*avoid_side_effects*/);
	return 1;
}

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor(duk_hthread *thr) {
	duk_uint_t arg_mask;

	arg_mask = duk_get_type_mask(thr, 0);

	if (!duk_is_constructor_call(thr) &&  /* not a constructor call */
	    ((arg_mask & (DUK_TYPE_MASK_NULL | DUK_TYPE_MASK_UNDEFINED)) == 0)) {  /* and argument not null or undefined */
		duk_to_object(thr, 0);
		return 1;
	}

	/* Pointer and buffer primitive values are treated like other
	 * primitives values which have a fully fledged object counterpart:
	 * promote to an object value.  Lightfuncs and plain buffers are
	 * coerced with ToObject() even they could also be returned as is.
	 */
	if (arg_mask & (DUK_TYPE_MASK_OBJECT |
	                DUK_TYPE_MASK_STRING |
	                DUK_TYPE_MASK_BOOLEAN |
	                DUK_TYPE_MASK_NUMBER |
	                DUK_TYPE_MASK_POINTER |
	                DUK_TYPE_MASK_BUFFER |
	                DUK_TYPE_MASK_LIGHTFUNC)) {
		/* For DUK_TYPE_OBJECT the coercion is a no-op and could
		 * be checked for explicitly, but Object(obj) calls are
		 * not very common so opt for minimal footprint.
		 */
		duk_to_object(thr, 0);
		return 1;
	}

	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                              DUK_BIDX_OBJECT_PROTOTYPE);
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) && defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_assign(duk_hthread *thr) {
	duk_idx_t nargs;
	duk_int_t idx;

	nargs = duk_get_top_require_min(thr, 1 /*min_top*/);

	duk_to_object(thr, 0);
	for (idx = 1; idx < nargs; idx++) {
		/* E7 19.1.2.1 (step 4a) */
		if (duk_is_null_or_undefined(thr, idx)) {
			continue;
		}

		/* duk_enum() respects ES2015+ [[OwnPropertyKeys]] ordering, which is
		 * convenient here.
		 */
		duk_to_object(thr, idx);
		duk_enum(thr, idx, DUK_ENUM_OWN_PROPERTIES_ONLY);
		while (duk_next(thr, -1, 1 /*get_value*/)) {
			/* [ target ... enum key value ] */
			duk_put_prop(thr, 0);
			/* [ target ... enum ] */
		}
		/* Could pop enumerator, but unnecessary because of duk_set_top()
		 * below.
		 */
	}

	duk_set_top(thr, 1);
	return 1;
}
#endif

#if defined(DUK_USE_OBJECT_BUILTIN) && defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_is(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 2);
	duk_push_boolean(thr, duk_samevalue(thr, 0, 1));
	return 1;
}
#endif

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_create(duk_hthread *thr) {
	duk_hobject *proto;

	DUK_ASSERT_TOP(thr, 2);

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	duk_hbufobj_promote_plain(thr, 0);
#endif
	proto = duk_require_hobject_accept_mask(thr, 0, DUK_TYPE_MASK_NULL);
	DUK_ASSERT(proto != NULL || duk_is_null(thr, 0));

	(void) duk_push_object_helper_proto(thr,
	                                    DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                    DUK_HOBJECT_FLAG_FASTREFS |
	                                    DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                                    proto);

	if (!duk_is_undefined(thr, 1)) {
		/* [ O Properties obj ] */

		duk_replace(thr, 0);

		/* [ obj Properties ] */

		/* Just call the "original" Object.defineProperties() to
		 * finish up.
		 */

		return duk_bi_object_constructor_define_properties(thr);
	}

	/* [ O Properties obj ] */

	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_define_properties(duk_hthread *thr) {
	duk_small_uint_t pass;
	duk_uint_t defprop_flags;
	duk_hobject *obj;
	duk_idx_t idx_value;
	duk_hobject *get;
	duk_hobject *set;

	/* Lightfunc and plain buffer handling by ToObject() coercion. */
	obj = duk_require_hobject_promote_mask(thr, 0, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	DUK_ASSERT(obj != NULL);

	duk_to_object(thr, 1);        /* properties object */

	DUK_DDD(DUK_DDDPRINT("target=%!iT, properties=%!iT",
	                     (duk_tval *) duk_get_tval(thr, 0),
	                     (duk_tval *) duk_get_tval(thr, 1)));

	/*
	 *  Two pass approach to processing the property descriptors.
	 *  On first pass validate and normalize all descriptors before
	 *  any changes are made to the target object.  On second pass
	 *  make the actual modifications to the target object.
	 *
	 *  Right now we'll just use the same normalize/validate helper
	 *  on both passes, ignoring its outputs on the first pass.
	 */

	for (pass = 0; pass < 2; pass++) {
		duk_set_top(thr, 2);  /* -> [ hobject props ] */
		duk_enum(thr, 1, DUK_ENUM_OWN_PROPERTIES_ONLY | DUK_ENUM_INCLUDE_SYMBOLS /*enum_flags*/);

		for (;;) {
			duk_hstring *key;

			/* [ hobject props enum(props) ] */

			duk_set_top(thr, 3);

			if (!duk_next(thr, 2, 1 /*get_value*/)) {
				break;
			}

			DUK_DDD(DUK_DDDPRINT("-> key=%!iT, desc=%!iT",
			                     (duk_tval *) duk_get_tval(thr, -2),
			                     (duk_tval *) duk_get_tval(thr, -1)));

			/* [ hobject props enum(props) key desc ] */

			duk_hobject_prepare_property_descriptor(thr,
			                                        4 /*idx_desc*/,
			                                        &defprop_flags,
			                                        &idx_value,
			                                        &get,
			                                        &set);

			/* [ hobject props enum(props) key desc [multiple values] ] */

			if (pass == 0) {
				continue;
			}

			/* This allows symbols on purpose. */
			key = duk_known_hstring(thr, 3);
			DUK_ASSERT(key != NULL);

			duk_hobject_define_property_helper(thr,
			                                   defprop_flags,
			                                   obj,
			                                   key,
			                                   idx_value,
			                                   get,
			                                   set,
			                                   1 /*throw_flag*/);
		}
	}

	/*
	 *  Return target object
	 */

	duk_dup_0(thr);
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_seal_freeze_shared(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 1);

	duk_seal_freeze_raw(thr, 0, (duk_bool_t) duk_get_current_magic(thr) /*is_freeze*/);
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_is_sealed_frozen_shared(duk_hthread *thr) {
	duk_hobject *h;
	duk_bool_t is_frozen;
	duk_uint_t mask;

	is_frozen = (duk_bool_t) duk_get_current_magic(thr);
	mask = duk_get_type_mask(thr, 0);
	if (mask & (DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER)) {
		DUK_ASSERT(is_frozen == 0 || is_frozen == 1);
		duk_push_boolean(thr, (mask & DUK_TYPE_MASK_LIGHTFUNC) ?
		                          1 :               /* lightfunc always frozen and sealed */
		                          (is_frozen ^ 1)); /* buffer sealed but not frozen (index props writable) */
	} else {
		/* ES2015 Sections 19.1.2.12, 19.1.2.13: anything other than an object
		 * is considered to be already sealed and frozen.
		 */
		h = duk_get_hobject(thr, 0);
		duk_push_boolean(thr, (h == NULL) ||
		                      duk_hobject_object_is_sealed_frozen_helper(thr, h, is_frozen /*is_frozen*/));
	}
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_to_locale_string(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 0);
	(void) duk_push_this_coercible_to_object(thr);
	duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_TO_STRING);
#if 0  /* This is mentioned explicitly in the E5.1 spec, but duk_call_method() checks for it in practice. */
	duk_require_callable(thr, 1);
#endif
	duk_dup_0(thr);  /* -> [ O toString O ] */
	duk_call_method(thr, 0);  /* XXX: call method tail call? */
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_value_of(duk_hthread *thr) {
	/* For lightfuncs and plain buffers, returns Object() coerced. */
	(void) duk_push_this_coercible_to_object(thr);
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_is_prototype_of(duk_hthread *thr) {
	duk_hobject *h_v;
	duk_hobject *h_obj;

	DUK_ASSERT_TOP(thr, 1);

	h_v = duk_get_hobject(thr, 0);
	if (!h_v) {
		duk_push_false(thr);  /* XXX: tail call: return duk_push_false(thr) */
		return 1;
	}

	h_obj = duk_push_this_coercible_to_object(thr);
	DUK_ASSERT(h_obj != NULL);

	/* E5.1 Section 15.2.4.6, step 3.a, lookup proto once before compare.
	 * Prototype loops should cause an error to be thrown.
	 */
	duk_push_boolean(thr, duk_hobject_prototype_chain_contains(thr, DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_v), h_obj, 0 /*ignore_loop*/));
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_has_own_property(duk_hthread *thr) {
	return (duk_ret_t) duk_hobject_object_ownprop_helper(thr, 0 /*required_desc_flags*/);
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_property_is_enumerable(duk_hthread *thr) {
	return (duk_ret_t) duk_hobject_object_ownprop_helper(thr, DUK_PROPDESC_FLAG_ENUMERABLE /*required_desc_flags*/);
}
#endif  /* DUK_USE_OBJECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
/* Shared helper to implement Object.getPrototypeOf,
 * Object.prototype.__proto__ getter, and Reflect.getPrototypeOf.
 *
 * http://www.ecma-international.org/ecma-262/6.0/index.html#sec-get-object.prototype.__proto__
 */
DUK_INTERNAL duk_ret_t duk_bi_object_getprototype_shared(duk_hthread *thr) {
	/*
	 *  magic = 0: __proto__ getter
	 *  magic = 1: Object.getPrototypeOf()
	 *  magic = 2: Reflect.getPrototypeOf()
	 */

	duk_hobject *h;
	duk_hobject *proto;
	duk_tval *tv;
	duk_int_t magic;

	magic = duk_get_current_magic(thr);

	if (magic == 0) {
		DUK_ASSERT_TOP(thr, 0);
		duk_push_this_coercible_to_object(thr);
	}
	DUK_ASSERT(duk_get_top(thr) >= 1);
	if (magic < 2) {
		/* ES2015 Section 19.1.2.9, step 1 */
		duk_to_object(thr, 0);
	}
	tv = DUK_GET_TVAL_POSIDX(thr, 0);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_BUFFER:
		proto = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
		break;
	case DUK_TAG_LIGHTFUNC:
		proto = thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE];
		break;
	case DUK_TAG_OBJECT:
		h = DUK_TVAL_GET_OBJECT(tv);
		proto = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h);
		break;
	default:
		/* This implicitly handles CheckObjectCoercible() caused
		 * TypeError.
		 */
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}
	if (proto != NULL) {
		duk_push_hobject(thr, proto);
	} else {
		duk_push_null(thr);
	}
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
/* Shared helper to implement ES2015 Object.setPrototypeOf,
 * Object.prototype.__proto__ setter, and Reflect.setPrototypeOf.
 *
 * http://www.ecma-international.org/ecma-262/6.0/index.html#sec-get-object.prototype.__proto__
 * http://www.ecma-international.org/ecma-262/6.0/index.html#sec-object.setprototypeof
 */
DUK_INTERNAL duk_ret_t duk_bi_object_setprototype_shared(duk_hthread *thr) {
	/*
	 *  magic = 0: __proto__ setter
	 *  magic = 1: Object.setPrototypeOf()
	 *  magic = 2: Reflect.setPrototypeOf()
	 */

	duk_hobject *h_obj;
	duk_hobject *h_new_proto;
	duk_hobject *h_curr;
	duk_ret_t ret_success = 1;  /* retval for success path */
	duk_uint_t mask;
	duk_int_t magic;

	/* Preliminaries for __proto__ and setPrototypeOf (E6 19.1.2.18 steps 1-4). */
	magic = duk_get_current_magic(thr);
	if (magic == 0) {
		duk_push_this_check_object_coercible(thr);
		duk_insert(thr, 0);
		if (!duk_check_type_mask(thr, 1, DUK_TYPE_MASK_NULL | DUK_TYPE_MASK_OBJECT)) {
			return 0;
		}

		/* __proto__ setter returns 'undefined' on success unlike the
		 * setPrototypeOf() call which returns the target object.
		 */
		ret_success = 0;
	} else {
		if (magic == 1) {
			duk_require_object_coercible(thr, 0);
		} else {
			duk_require_hobject_accept_mask(thr, 0,
			                                DUK_TYPE_MASK_LIGHTFUNC |
			                                DUK_TYPE_MASK_BUFFER);
		}
		duk_require_type_mask(thr, 1, DUK_TYPE_MASK_NULL | DUK_TYPE_MASK_OBJECT);
	}

	h_new_proto = duk_get_hobject(thr, 1);
	/* h_new_proto may be NULL */

	mask = duk_get_type_mask(thr, 0);
	if (mask & (DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER)) {
		duk_hobject *curr_proto;
		curr_proto = thr->builtins[(mask & DUK_TYPE_MASK_LIGHTFUNC) ?
		                               DUK_BIDX_FUNCTION_PROTOTYPE :
		                               DUK_BIDX_UINT8ARRAY_PROTOTYPE];
		if (h_new_proto == curr_proto) {
			goto skip;
		}
		goto fail_nonextensible;
	}
	h_obj = duk_get_hobject(thr, 0);
	if (h_obj == NULL) {
		goto skip;
	}
	DUK_ASSERT(h_obj != NULL);

	/* [[SetPrototypeOf]] standard behavior, E6 9.1.2. */
	/* TODO: implement Proxy object support here */

	if (h_new_proto == DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_obj)) {
		goto skip;
	}
	if (!DUK_HOBJECT_HAS_EXTENSIBLE(h_obj)) {
		goto fail_nonextensible;
	}
	for (h_curr = h_new_proto; h_curr != NULL; h_curr = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_curr)) {
		/* Loop prevention. */
		if (h_curr == h_obj) {
			goto fail_loop;
		}
	}
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, h_obj, h_new_proto);
	/* fall thru */

 skip:
	duk_set_top(thr, 1);
	if (magic == 2) {
		duk_push_true(thr);
	}
	return ret_success;

 fail_nonextensible:
 fail_loop:
	if (magic != 2) {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	} else {
		duk_push_false(thr);
		return 1;
	}
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_define_property(duk_hthread *thr) {
	/*
	 *  magic = 0: Object.defineProperty()
	 *  magic = 1: Reflect.defineProperty()
	 */

	duk_hobject *obj;
	duk_hstring *key;
	duk_hobject *get;
	duk_hobject *set;
	duk_idx_t idx_value;
	duk_uint_t defprop_flags;
	duk_small_uint_t magic;
	duk_bool_t throw_flag;
	duk_bool_t ret;

	DUK_ASSERT(thr != NULL);

	DUK_DDD(DUK_DDDPRINT("Object.defineProperty(): ctx=%p obj=%!T key=%!T desc=%!T",
	                     (void *) thr,
	                     (duk_tval *) duk_get_tval(thr, 0),
	                     (duk_tval *) duk_get_tval(thr, 1),
	                     (duk_tval *) duk_get_tval(thr, 2)));

	/* [ obj key desc ] */

	magic = (duk_small_uint_t) duk_get_current_magic(thr);

	/* Lightfuncs are currently supported by coercing to a temporary
	 * Function object; changes will be allowed (the coerced value is
	 * extensible) but will be lost.  Same for plain buffers.
	 */
	obj = duk_require_hobject_promote_mask(thr, 0, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	DUK_ASSERT(obj != NULL);
	key = duk_to_property_key_hstring(thr, 1);
	(void) duk_require_hobject(thr, 2);

	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(duk_get_hobject(thr, 2) != NULL);

	/*
	 *  Validate and convert argument property descriptor (an ECMAScript
	 *  object) into a set of defprop_flags and possibly property value,
	 *  getter, and/or setter values on the value stack.
	 *
	 *  Lightfunc set/get values are coerced to full Functions.
	 */

	duk_hobject_prepare_property_descriptor(thr,
	                                        2 /*idx_desc*/,
	                                        &defprop_flags,
	                                        &idx_value,
	                                        &get,
	                                        &set);

	/*
	 *  Use Object.defineProperty() helper for the actual operation.
	 */

	DUK_ASSERT(magic == 0U || magic == 1U);
	throw_flag = magic ^ 1U;
	ret = duk_hobject_define_property_helper(thr,
	                                         defprop_flags,
	                                         obj,
	                                         key,
	                                         idx_value,
	                                         get,
	                                         set,
	                                         throw_flag);

	/* Ignore the normalize/validate helper outputs on the value stack,
	 * they're popped automatically.
	 */

	if (magic == 0U) {
		/* Object.defineProperty(): return target object. */
		duk_push_hobject(thr, obj);
	} else {
		/* Reflect.defineProperty(): return success/fail. */
		duk_push_boolean(thr, ret);
	}
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_get_own_property_descriptor(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 2);

	/* ES2015 Section 19.1.2.6, step 1 */
	if (duk_get_current_magic(thr) == 0) {
		duk_to_object(thr, 0);
	}

	/* [ obj key ] */

	duk_hobject_object_get_own_property_descriptor(thr, -2);
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_is_extensible(duk_hthread *thr) {
	/*
	 *  magic = 0: Object.isExtensible()
	 *  magic = 1: Reflect.isExtensible()
	 */

	duk_hobject *h;

	if (duk_get_current_magic(thr) == 0) {
		h = duk_get_hobject(thr, 0);
	} else {
		/* Reflect.isExtensible(): throw if non-object, but we accept lightfuncs
		 * and plain buffers here because they pretend to be objects.
		 */
		h = duk_require_hobject_accept_mask(thr, 0, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	}

	duk_push_boolean(thr, (h != NULL) && DUK_HOBJECT_HAS_EXTENSIBLE(h));
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
/* Shared helper for various key/symbol listings, magic:
 * 0=Object.keys()
 * 1=Object.getOwnPropertyNames(),
 * 2=Object.getOwnPropertySymbols(),
 * 3=Reflect.ownKeys()
 */
DUK_LOCAL const duk_small_uint_t duk__object_keys_enum_flags[4] = {
	/* Object.keys() */
	DUK_ENUM_OWN_PROPERTIES_ONLY |
	    DUK_ENUM_NO_PROXY_BEHAVIOR,

	/* Object.getOwnPropertyNames() */
	DUK_ENUM_INCLUDE_NONENUMERABLE |
	    DUK_ENUM_OWN_PROPERTIES_ONLY |
	    DUK_ENUM_NO_PROXY_BEHAVIOR,

	/* Object.getOwnPropertySymbols() */
	DUK_ENUM_INCLUDE_SYMBOLS |
	    DUK_ENUM_OWN_PROPERTIES_ONLY |
	    DUK_ENUM_EXCLUDE_STRINGS |
	    DUK_ENUM_INCLUDE_NONENUMERABLE |
	    DUK_ENUM_NO_PROXY_BEHAVIOR,

	/* Reflect.ownKeys() */
	DUK_ENUM_INCLUDE_SYMBOLS |
	    DUK_ENUM_OWN_PROPERTIES_ONLY |
	    DUK_ENUM_INCLUDE_NONENUMERABLE |
	    DUK_ENUM_NO_PROXY_BEHAVIOR
};

DUK_INTERNAL duk_ret_t duk_bi_object_constructor_keys_shared(duk_hthread *thr) {
	duk_hobject *obj;
#if defined(DUK_USE_ES6_PROXY)
	duk_hobject *h_proxy_target;
	duk_hobject *h_proxy_handler;
	duk_hobject *h_trap_result;
#endif
	duk_small_uint_t enum_flags;
	duk_int_t magic;

	DUK_ASSERT_TOP(thr, 1);

	magic = duk_get_current_magic(thr);
	if (magic == 3) {
		/* ES2015 Section 26.1.11 requires a TypeError for non-objects.  Lightfuncs
		 * and plain buffers pretend to be objects, so accept those too.
		 */
		obj = duk_require_hobject_promote_mask(thr, 0, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	} else {
		/* ES2015: ToObject coerce. */
		obj = duk_to_hobject(thr, 0);
	}
	DUK_ASSERT(obj != NULL);
	DUK_UNREF(obj);

	/* XXX: proxy chains */

#if defined(DUK_USE_ES6_PROXY)
	/* XXX: better sharing of code between proxy target call sites */
	if (DUK_LIKELY(!duk_hobject_proxy_check(obj,
	                                        &h_proxy_target,
	                                        &h_proxy_handler))) {
		goto skip_proxy;
	}

	duk_push_hobject(thr, h_proxy_handler);
	if (!duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_OWN_KEYS)) {
		/* Careful with reachability here: don't pop 'obj' before pushing
		 * proxy target.
		 */
		DUK_DDD(DUK_DDDPRINT("no ownKeys trap, get keys of target instead"));
		duk_pop_2(thr);
		duk_push_hobject(thr, h_proxy_target);
		duk_replace(thr, 0);
		DUK_ASSERT_TOP(thr, 1);
		goto skip_proxy;
	}

	/* [ obj handler trap ] */
	duk_insert(thr, -2);
	duk_push_hobject(thr, h_proxy_target);  /* -> [ obj trap handler target ] */
	duk_call_method(thr, 1 /*nargs*/);      /* -> [ obj trap_result ] */
	h_trap_result = duk_require_hobject(thr, -1);
	DUK_UNREF(h_trap_result);

	magic = duk_get_current_magic(thr);
	DUK_ASSERT(magic >= 0 && magic < (duk_int_t) (sizeof(duk__object_keys_enum_flags) / sizeof(duk_small_uint_t)));
	enum_flags = duk__object_keys_enum_flags[magic];

	duk_proxy_ownkeys_postprocess(thr, h_proxy_target, enum_flags);
	return 1;

 skip_proxy:
#endif  /* DUK_USE_ES6_PROXY */

	DUK_ASSERT_TOP(thr, 1);
	magic = duk_get_current_magic(thr);
	DUK_ASSERT(magic >= 0 && magic < (duk_int_t) (sizeof(duk__object_keys_enum_flags) / sizeof(duk_small_uint_t)));
	enum_flags = duk__object_keys_enum_flags[magic];
	return duk_hobject_get_enumerated_keys(thr, enum_flags);
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

#if defined(DUK_USE_OBJECT_BUILTIN) || defined(DUK_USE_REFLECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_object_constructor_prevent_extensions(duk_hthread *thr) {
	/*
	 *  magic = 0: Object.preventExtensions()
	 *  magic = 1: Reflect.preventExtensions()
	 */

	duk_hobject *h;
	duk_uint_t mask;
	duk_int_t magic;

	magic = duk_get_current_magic(thr);

	/* Silent success for lightfuncs and plain buffers always. */
	mask = DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER;

	/* Object.preventExtensions() silent success for non-object. */
	if (magic == 0) {
		mask |= DUK_TYPE_MASK_UNDEFINED |
		        DUK_TYPE_MASK_NULL |
		        DUK_TYPE_MASK_BOOLEAN |
		        DUK_TYPE_MASK_NUMBER |
		        DUK_TYPE_MASK_STRING |
		        DUK_TYPE_MASK_POINTER;
	}

	if (duk_check_type_mask(thr, 0, mask)) {
		/* Not an object, already non-extensible so always success. */
		goto done;
	}
	h = duk_require_hobject(thr, 0);
	DUK_ASSERT(h != NULL);

	DUK_HOBJECT_CLEAR_EXTENSIBLE(h);

	/* A non-extensible object cannot gain any more properties,
	 * so this is a good time to compact.
	 */
	duk_hobject_compact_props(thr, h);

 done:
	if (magic == 1) {
		duk_push_true(thr);
	}
	return 1;
}
#endif  /* DUK_USE_OBJECT_BUILTIN || DUK_USE_REFLECT_BUILTIN */

/*
 *  __defineGetter__, __defineSetter__, __lookupGetter__, __lookupSetter__
 */

#if defined(DUK_USE_ES8)
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_defineaccessor(duk_hthread *thr) {
	duk_push_this(thr);
	duk_insert(thr, 0);
	duk_to_object(thr, 0);
	duk_require_callable(thr, 2);

	/* [ ToObject(this) key getter/setter ] */

	/* ToPropertyKey() coercion is not needed, duk_def_prop() does it. */
	duk_def_prop(thr, 0, DUK_DEFPROP_SET_ENUMERABLE |
	                     DUK_DEFPROP_SET_CONFIGURABLE |
	                     (duk_get_current_magic(thr) ? DUK_DEFPROP_HAVE_SETTER : DUK_DEFPROP_HAVE_GETTER));
	return 0;
}
DUK_INTERNAL duk_ret_t duk_bi_object_prototype_lookupaccessor(duk_hthread *thr) {
	duk_uint_t sanity;

	duk_push_this(thr);
	duk_to_object(thr, -1);

	/* XXX: Prototype walk (with sanity) should be a core property
	 * operation, could add a flag to e.g. duk_get_prop_desc().
	 */

	/* ToPropertyKey() coercion is not needed, duk_get_prop_desc() does it. */
	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	while (!duk_is_undefined(thr, -1)) {
		/* [ key obj ] */
		duk_dup(thr, 0);
		duk_get_prop_desc(thr, 1, 0 /*flags*/);
		if (!duk_is_undefined(thr, -1)) {
			duk_get_prop_stridx(thr, -1, (duk_get_current_magic(thr) != 0 ? DUK_STRIDX_SET : DUK_STRIDX_GET));
			return 1;
		}
		duk_pop(thr);

		if (DUK_UNLIKELY(sanity-- == 0)) {
			DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
			DUK_WO_NORETURN(return 0;);
		}

		duk_get_prototype(thr, -1);
		duk_remove(thr, -2);
	}
	return 1;
}
#endif  /* DUK_USE_ES8 */
/*
 *  High resolution time API (performance.now() et al)
 *
 *  API specification: https://encoding.spec.whatwg.org/#ap://www.w3.org/TR/hr-time/
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_PERFORMANCE_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_performance_now(duk_hthread *thr) {
	/* From API spec:
	 * The DOMHighResTimeStamp type is used to store a time value in
	 * milliseconds, measured relative from the time origin, global
	 * monotonic clock, or a time value that represents a duration
	 * between two DOMHighResTimeStamp's.
	 */
	duk_push_number(thr, duk_time_get_monotonic_time(thr));
	return 1;
}

#if 0  /* Missing until semantics decided. */
DUK_INTERNAL duk_ret_t duk_bi_performance_timeorigin_getter(duk_hthread *thr) {
	/* No decision yet how to handle timeOrigins, e.g. should one be
	 * initialized per heap, or per global object set.  See
	 * https://www.w3.org/TR/hr-time/#time-origin.
	 */
	duk_push_uint(thr, 0);
	return 1;
}
#endif  /* 0 */
#endif  /* DUK_USE_PERFORMANCE_BUILTIN */
/*
 *  Pointer built-ins
 */

/* #include duk_internal.h -> already included */

/*
 *  Constructor
 */

DUK_INTERNAL duk_ret_t duk_bi_pointer_constructor(duk_hthread *thr) {
	/* XXX: this behavior is quite useless now; it would be nice to be able
	 * to create pointer values from e.g. numbers or strings.  Numbers are
	 * problematic on 64-bit platforms though.  Hex encoded strings?
	 */
	if (duk_get_top(thr) == 0) {
		duk_push_pointer(thr, NULL);
	} else {
		duk_to_pointer(thr, 0);
	}
	DUK_ASSERT(duk_is_pointer(thr, 0));
	duk_set_top(thr, 1);

	if (duk_is_constructor_call(thr)) {
		(void) duk_push_object_helper(thr,
		                              DUK_HOBJECT_FLAG_EXTENSIBLE |
		                              DUK_HOBJECT_FLAG_FASTREFS |
		                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_POINTER),
		                              DUK_BIDX_POINTER_PROTOTYPE);

		/* Pointer object internal value is immutable. */
		duk_dup_0(thr);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);
	}
	/* Note: unbalanced stack on purpose */

	return 1;
}

/*
 *  toString(), valueOf()
 */

DUK_INTERNAL duk_ret_t duk_bi_pointer_prototype_tostring_shared(duk_hthread *thr) {
	duk_tval *tv;
	duk_small_int_t to_string = duk_get_current_magic(thr);

	duk_push_this(thr);
	tv = duk_require_tval(thr, -1);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_POINTER(tv)) {
		/* nop */
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		/* Must be a "pointer object", i.e. class "Pointer" */
		if (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_POINTER) {
			goto type_error;
		}

		duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
	} else {
		goto type_error;
	}

	if (to_string) {
		duk_to_string(thr, -1);
	}
	return 1;

 type_error:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}
/*
 *  Promise built-in
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_PROMISE_BUILTIN)

DUK_INTERNAL duk_ret_t duk_bi_promise_constructor(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_all(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_race(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_reject(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_resolve(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_catch(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL duk_ret_t duk_bi_promise_then(duk_hthread *thr) {
	DUK_ERROR_TYPE(thr, "unimplemented");
	DUK_WO_NORETURN(return 0;);
}

#endif  /* DUK_USE_PROMISE_BUILTIN */
/*
 *  Proxy built-in (ES2015)
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ES6_PROXY)
/* Post-process a Proxy ownKeys() result at stack top.  Push a cleaned up
 * array of valid result keys (strings or symbols).  TypeError for invalid
 * values.  Flags are shared with duk_enum().
 */
DUK_INTERNAL void duk_proxy_ownkeys_postprocess(duk_hthread *thr, duk_hobject *h_proxy_target, duk_uint_t flags) {
	duk_uarridx_t i, len, idx;
	duk_propdesc desc;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(h_proxy_target != NULL);

	len = (duk_uarridx_t) duk_get_length(thr, -1);
	idx = 0;
	duk_push_array(thr);
	/* XXX: preallocated dense array, fill in directly */
	for (i = 0; i < len; i++) {
		duk_hstring *h;

		/* [ obj trap_result res_arr ] */
		(void) duk_get_prop_index(thr, -2, i);
		h = duk_get_hstring(thr, -1);
		if (h == NULL) {
			DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr);
			DUK_WO_NORETURN(return;);
		}

		if (!(flags & DUK_ENUM_INCLUDE_NONENUMERABLE)) {
			/* No support for 'getOwnPropertyDescriptor' trap yet,
			 * so check enumerability always from target object
			 * descriptor.
			 */
			if (duk_hobject_get_own_propdesc(thr, h_proxy_target, duk_known_hstring(thr, -1), &desc, 0 /*flags*/)) {
				if ((desc.flags & DUK_PROPDESC_FLAG_ENUMERABLE) == 0) {
					DUK_DDD(DUK_DDDPRINT("ignore non-enumerable property: %!T", duk_get_tval(thr, -1)));
					goto skip_key;
				}
			} else {
				DUK_DDD(DUK_DDDPRINT("ignore non-existent property: %!T", duk_get_tval(thr, -1)));
				goto skip_key;
			}
		}
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			if (!(flags & DUK_ENUM_INCLUDE_SYMBOLS)) {
				DUK_DDD(DUK_DDDPRINT("ignore symbol property: %!T", duk_get_tval(thr, -1)));
				goto skip_key;
			}
			if (DUK_HSTRING_HAS_HIDDEN(h) && !(flags & DUK_ENUM_INCLUDE_HIDDEN)) {
				DUK_DDD(DUK_DDDPRINT("ignore hidden symbol property: %!T", duk_get_tval(thr, -1)));
				goto skip_key;
			}
		} else {
			if (flags & DUK_ENUM_EXCLUDE_STRINGS) {
				DUK_DDD(DUK_DDDPRINT("ignore string property: %!T", duk_get_tval(thr, -1)));
				goto skip_key;
			}
		}

		/* [ obj trap_result res_arr propname ] */
		duk_put_prop_index(thr, -2, idx++);
		continue;

	 skip_key:
		duk_pop(thr);
		continue;
	}

	/* XXX: Missing trap result validation for non-configurable target keys
	 * (must be present), for non-extensible target all target keys must be
	 * present and no extra keys can be present.
	 * http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys
	 */

	/* XXX: The key enumerability check should trigger the "getOwnPropertyDescriptor"
	 * trap which has not yet been implemented.  In the absence of such a trap,
	 * the enumerability should be checked from the target object; this is
	 * handled above.
	 */
}
#endif  /* DUK_USE_ES6_PROXY */

#if defined(DUK_USE_ES6_PROXY)
DUK_INTERNAL duk_ret_t duk_bi_proxy_constructor(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 2);  /* [ target handler ] */

	duk_require_constructor_call(thr);
	duk_push_proxy(thr, 0 /*flags*/);  /* [ target handler ] -> [ proxy ] */
	return 1;  /* replacement */
}
#endif  /* DUK_USE_ES6_PROXY */
/*
 *  'Reflect' built-in (ES2016 Section 26.1)
 *  http://www.ecma-international.org/ecma-262/7.0/#sec-reflect-object
 *
 *  Many Reflect built-in functions are provided by shared helpers in
 *  duk_bi_object.c or duk_bi_function.c.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_REFLECT_BUILTIN)
DUK_INTERNAL duk_ret_t duk_bi_reflect_object_delete_property(duk_hthread *thr) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_bool_t ret;

	DUK_ASSERT_TOP(thr, 2);
	(void) duk_require_hobject(thr, 0);
	(void) duk_to_string(thr, 1);

	/* [ target key ] */

	DUK_ASSERT(thr != NULL);
	tv_obj = DUK_GET_TVAL_POSIDX(thr, 0);
	tv_key = DUK_GET_TVAL_POSIDX(thr, 1);
	ret = duk_hobject_delprop(thr, tv_obj, tv_key, 0 /*throw_flag*/);
	duk_push_boolean(thr, ret);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_reflect_object_get(duk_hthread *thr) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_idx_t nargs;

	DUK_ASSERT(thr != NULL);
	nargs = duk_get_top_require_min(thr, 2 /*min_top*/);
	(void) duk_require_hobject(thr, 0);
	(void) duk_to_string(thr, 1);
	if (nargs >= 3 && !duk_strict_equals(thr, 0, 2)) {
		/* XXX: [[Get]] receiver currently unsupported */
		DUK_ERROR_UNSUPPORTED(thr);
		DUK_WO_NORETURN(return 0;);
	}

	/* [ target key receiver? ...? ] */

	tv_obj = DUK_GET_TVAL_POSIDX(thr, 0);
	tv_key = DUK_GET_TVAL_POSIDX(thr, 1);
	(void) duk_hobject_getprop(thr, tv_obj, tv_key);  /* This could also be a duk_get_prop(). */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_reflect_object_has(duk_hthread *thr) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_bool_t ret;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT_TOP(thr, 2);
	(void) duk_require_hobject(thr, 0);
	(void) duk_to_string(thr, 1);

	/* [ target key ] */

	tv_obj = DUK_GET_TVAL_POSIDX(thr, 0);
	tv_key = DUK_GET_TVAL_POSIDX(thr, 1);
	ret = duk_hobject_hasprop(thr, tv_obj, tv_key);
	duk_push_boolean(thr, ret);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_reflect_object_set(duk_hthread *thr) {
	duk_tval *tv_obj;
	duk_tval *tv_key;
	duk_tval *tv_val;
	duk_idx_t nargs;
	duk_bool_t ret;

	DUK_ASSERT(thr != NULL);
	nargs = duk_get_top_require_min(thr, 3 /*min_top*/);
	(void) duk_require_hobject(thr, 0);
	(void) duk_to_string(thr, 1);
	if (nargs >= 4 && !duk_strict_equals(thr, 0, 3)) {
		/* XXX: [[Set]] receiver currently unsupported */
		DUK_ERROR_UNSUPPORTED(thr);
		DUK_WO_NORETURN(return 0;);
	}

	/* [ target key value receiver? ...? ] */

	tv_obj = DUK_GET_TVAL_POSIDX(thr, 0);
	tv_key = DUK_GET_TVAL_POSIDX(thr, 1);
	tv_val = DUK_GET_TVAL_POSIDX(thr, 2);
	ret = duk_hobject_putprop(thr, tv_obj, tv_key, tv_val, 0 /*throw_flag*/);
	duk_push_boolean(thr, ret);
	return 1;
}
#endif  /* DUK_USE_REFLECT_BUILTIN */
/*
 *  RegExp built-ins
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_REGEXP_SUPPORT)

DUK_LOCAL void duk__get_this_regexp(duk_hthread *thr) {
	duk_hobject *h;

	duk_push_this(thr);
	h = duk_require_hobject_with_class(thr, -1, DUK_HOBJECT_CLASS_REGEXP);
	DUK_ASSERT(h != NULL);
	DUK_UNREF(h);
	duk_insert(thr, 0);  /* prepend regexp to valstack 0 index */
}

/* XXX: much to improve (code size) */
DUK_INTERNAL duk_ret_t duk_bi_regexp_constructor(duk_hthread *thr) {
	duk_hobject *h_pattern;

	DUK_ASSERT_TOP(thr, 2);
	h_pattern = duk_get_hobject(thr, 0);

	if (!duk_is_constructor_call(thr) &&
	    h_pattern != NULL &&
	    DUK_HOBJECT_GET_CLASS_NUMBER(h_pattern) == DUK_HOBJECT_CLASS_REGEXP &&
	    duk_is_undefined(thr, 1)) {
		/* Called as a function, pattern has [[Class]] "RegExp" and
		 * flags is undefined -> return object as is.
		 */
		/* XXX: ES2015 has a NewTarget SameValue() check which is not
		 * yet implemented.
		 */
		duk_dup_0(thr);
		return 1;
	}

	/* Else functionality is identical for function call and constructor
	 * call.
	 */

	if (h_pattern != NULL &&
	    DUK_HOBJECT_GET_CLASS_NUMBER(h_pattern) == DUK_HOBJECT_CLASS_REGEXP) {
		duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_SOURCE);
		if (duk_is_undefined(thr, 1)) {
			/* In ES5 one would need to read the flags individually;
			 * in ES2015 just read .flags.
			 */
			duk_get_prop_stridx(thr, 0, DUK_STRIDX_FLAGS);
		} else {
			/* In ES2015 allowed; overrides argument RegExp flags. */
			duk_dup_1(thr);
		}
	} else {
		if (duk_is_undefined(thr, 0)) {
			duk_push_hstring_empty(thr);
		} else {
			duk_dup_0(thr);
			duk_to_string(thr, -1);  /* Rejects Symbols. */
		}
		if (duk_is_undefined(thr, 1)) {
			duk_push_hstring_empty(thr);
		} else {
			duk_dup_1(thr);
			duk_to_string(thr, -1);  /* Rejects Symbols. */
		}

		/* [ ... pattern flags ] */
	}

	DUK_DDD(DUK_DDDPRINT("RegExp constructor/function call, pattern=%!T, flags=%!T",
	                     (duk_tval *) duk_get_tval(thr, -2), (duk_tval *) duk_get_tval(thr, -1)));

	/* [ ... pattern flags ] (both uncoerced) */

	duk_to_string(thr, -2);
	duk_to_string(thr, -1);
	duk_regexp_compile(thr);

	/* [ ... bytecode escaped_source ] */

	duk_regexp_create_instance(thr);

	/* [ ... RegExp ] */

	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_exec(duk_hthread *thr) {
	duk__get_this_regexp(thr);

	/* [ regexp input ] */

	duk_regexp_match(thr);

	/* [ result ] */

	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_test(duk_hthread *thr) {
	duk__get_this_regexp(thr);

	/* [ regexp input ] */

	/* result object is created and discarded; wasteful but saves code space */
	duk_regexp_match(thr);

	/* [ result ] */

	duk_push_boolean(thr, (duk_is_null(thr, -1) ? 0 : 1));

	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_tostring(duk_hthread *thr) {
	/* This must be generic in ES2015 and later. */
	DUK_ASSERT_TOP(thr, 0);
	duk_push_this(thr);
	duk_push_literal(thr, "/");
	duk_get_prop_stridx(thr, 0, DUK_STRIDX_SOURCE);
	duk_dup_m2(thr);  /* another "/" */
	duk_get_prop_stridx(thr, 0, DUK_STRIDX_FLAGS);
	duk_concat(thr, 4);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_flags(duk_hthread *thr) {
	/* .flags is ES2015 but present even when ES2015 bindings are
	 * disabled because the constructor relies on it.
	 */
	duk_uint8_t buf[8];  /* enough for all flags + NUL */
	duk_uint8_t *p = buf;

	/* .flags is generic and works on any object. */
	duk_push_this(thr);
	(void) duk_require_hobject(thr, -1);
	if (duk_get_prop_stridx_boolean(thr, 0, DUK_STRIDX_GLOBAL, NULL)) {
		*p++ = DUK_ASC_LC_G;
	}
	if (duk_get_prop_stridx_boolean(thr, 0, DUK_STRIDX_IGNORE_CASE, NULL)) {
		*p++ = DUK_ASC_LC_I;
	}
	if (duk_get_prop_stridx_boolean(thr, 0, DUK_STRIDX_MULTILINE, NULL)) {
		*p++ = DUK_ASC_LC_M;
	}
	/* .unicode: to be added */
	/* .sticky: to be added */
	*p++ = DUK_ASC_NUL;
	DUK_ASSERT((duk_size_t) (p - buf) <= sizeof(buf));

	duk_push_string(thr, (const char *) buf);
	return 1;
}

/* Shared helper for providing .source, .global, .multiline, etc getters. */
DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_shared_getter(duk_hthread *thr) {
	duk_hstring *h_bc;
	duk_small_uint_t re_flags;
	duk_hobject *h;
	duk_int_t magic;

	DUK_ASSERT_TOP(thr, 0);

	duk_push_this(thr);
	h = duk_require_hobject(thr, -1);
	magic = duk_get_current_magic(thr);

	if (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_REGEXP) {
		duk_xget_owndataprop_stridx_short(thr, 0, DUK_STRIDX_INT_SOURCE);
		duk_xget_owndataprop_stridx_short(thr, 0, DUK_STRIDX_INT_BYTECODE);
		h_bc = duk_require_hstring(thr, -1);
		re_flags = (duk_small_uint_t) DUK_HSTRING_GET_DATA(h_bc)[0];  /* Safe even if h_bc length is 0 (= NUL) */
		duk_pop(thr);
	} else if (h == thr->builtins[DUK_BIDX_REGEXP_PROTOTYPE]) {
		/* In ES2015 and ES2016 a TypeError would be thrown here.
		 * However, this had real world issues so ES2017 draft
		 * allows RegExp.prototype specifically, returning '(?:)'
		 * for .source and undefined for all flags.
		 */
		if (magic != 16 /* .source */) {
			return 0;
		}
		duk_push_literal(thr, "(?:)");  /* .source handled by switch-case */
		re_flags = 0;
	} else {
		DUK_DCERROR_TYPE_INVALID_ARGS(thr);
	}

	/* [ regexp source ] */

	switch (magic) {
	case 0: {  /* global */
		duk_push_boolean(thr, (re_flags & DUK_RE_FLAG_GLOBAL));
		break;
	}
	case 1: {  /* ignoreCase */
		duk_push_boolean(thr, (re_flags & DUK_RE_FLAG_IGNORE_CASE));
		break;
	}
	case 2: {  /* multiline */
		duk_push_boolean(thr, (re_flags & DUK_RE_FLAG_MULTILINE));
		break;
	}
#if 0
	/* Don't provide until implemented to avoid interfering with feature
	 * detection in user code.
	 */
	case 3:    /* sticky */
	case 4: {  /* unicode */
		duk_push_false(thr);
		break;
	}
#endif
	default: {  /* source */
		/* leave 'source' on top */
		break;
	}
	}

	return 1;
}

#endif  /* DUK_USE_REGEXP_SUPPORT */
/*
 *  String built-ins
 *
 *  Most String built-ins must only accept strings (or String objects).
 *  Symbols, represented internally as strings, must be generally rejected.
 *  The duk_push_this_coercible_to_string() helper does this automatically.
 */

/* XXX: There are several limitations in the current implementation for
 * strings with >= 0x80000000UL characters.  In some cases one would need
 * to be able to represent the range [-0xffffffff,0xffffffff] and so on.
 * Generally character and byte length are assumed to fit into signed 32
 * bits (< 0x80000000UL).  Places with issues are not marked explicitly
 * below in all cases, look for signed type usage (duk_int_t etc) for
 * offsets/lengths.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_STRING_BUILTIN)

/*
 *  Helpers
 */

DUK_LOCAL duk_hstring *duk__str_tostring_notregexp(duk_hthread *thr, duk_idx_t idx) {
	duk_hstring *h;

	if (duk_get_class_number(thr, idx) == DUK_HOBJECT_CLASS_REGEXP) {
		DUK_ERROR_TYPE_INVALID_ARGS(thr);
		DUK_WO_NORETURN(return NULL;);
	}
	h = duk_to_hstring(thr, idx);
	DUK_ASSERT(h != NULL);

	return h;
}

DUK_LOCAL duk_int_t duk__str_search_shared(duk_hthread *thr, duk_hstring *h_this, duk_hstring *h_search, duk_int_t start_cpos, duk_bool_t backwards) {
	duk_int_t cpos;
	duk_int_t bpos;
	const duk_uint8_t *p_start, *p_end, *p;
	const duk_uint8_t *q_start;
	duk_int_t q_blen;
	duk_uint8_t firstbyte;
	duk_uint8_t t;

	cpos = start_cpos;

	/* Empty searchstring always matches; cpos must be clamped here.
	 * (If q_blen were < 0 due to clamped coercion, it would also be
	 * caught here.)
	 */
	q_start = DUK_HSTRING_GET_DATA(h_search);
	q_blen = (duk_int_t) DUK_HSTRING_GET_BYTELEN(h_search);
	if (q_blen <= 0) {
		return cpos;
	}
	DUK_ASSERT(q_blen > 0);

	bpos = (duk_int_t) duk_heap_strcache_offset_char2byte(thr, h_this, (duk_uint32_t) cpos);

	p_start = DUK_HSTRING_GET_DATA(h_this);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_this);
	p = p_start + bpos;

	/* This loop is optimized for size.  For speed, there should be
	 * two separate loops, and we should ensure that memcmp() can be
	 * used without an extra "will searchstring fit" check.  Doing
	 * the preconditioning for 'p' and 'p_end' is easy but cpos
	 * must be updated if 'p' is wound back (backward scanning).
	 */

	firstbyte = q_start[0];  /* leading byte of match string */
	while (p <= p_end && p >= p_start) {
		t = *p;

		/* For ECMAScript strings, this check can only match for
		 * initial UTF-8 bytes (not continuation bytes).  For other
		 * strings all bets are off.
		 */

		if ((t == firstbyte) && ((duk_size_t) (p_end - p) >= (duk_size_t) q_blen)) {
			DUK_ASSERT(q_blen > 0);
			if (duk_memcmp((const void *) p, (const void *) q_start, (size_t) q_blen) == 0) {
				return cpos;
			}
		}

		/* track cpos while scanning */
		if (backwards) {
			/* when going backwards, we decrement cpos 'early';
			 * 'p' may point to a continuation byte of the char
			 * at offset 'cpos', but that's OK because we'll
			 * backtrack all the way to the initial byte.
			 */
			if ((t & 0xc0) != 0x80) {
				cpos--;
			}
			p--;
		} else {
			if ((t & 0xc0) != 0x80) {
				cpos++;
			}
			p++;
		}
	}

	/* Not found.  Empty string case is handled specially above. */
	return -1;
}

/*
 *  Constructor
 */

DUK_INTERNAL duk_ret_t duk_bi_string_constructor(duk_hthread *thr) {
	duk_hstring *h;
	duk_uint_t flags;

	/* String constructor needs to distinguish between an argument not given at all
	 * vs. given as 'undefined'.  We're a vararg function to handle this properly.
	 */

	/* XXX: copy current activation flags to thr, including current magic,
	 * is_constructor_call etc.  This takes a few bytes in duk_hthread but
	 * makes call sites smaller (there are >30 is_constructor_call and get
	 * current magic call sites.
	 */

	if (duk_get_top(thr) == 0) {
		duk_push_hstring_empty(thr);
	} else {
		h = duk_to_hstring_acceptsymbol(thr, 0);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h) && !duk_is_constructor_call(thr))) {
			duk_push_symbol_descriptive_string(thr, h);
			duk_replace(thr, 0);
		}
	}
	duk_to_string(thr, 0);  /* catches symbol argument for constructor call */
	DUK_ASSERT(duk_is_string(thr, 0));
	duk_set_top(thr, 1);  /* Top may be 1 or larger. */

	if (duk_is_constructor_call(thr)) {
		/* String object internal value is immutable */
		flags = DUK_HOBJECT_FLAG_EXTENSIBLE |
		        DUK_HOBJECT_FLAG_FASTREFS |
		        DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ |
		        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_STRING);
		duk_push_object_helper(thr, flags, DUK_BIDX_STRING_PROTOTYPE);
		duk_dup_0(thr);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);
	}
	/* Note: unbalanced stack on purpose */

	return 1;
}

DUK_LOCAL duk_ret_t duk__construct_from_codepoints(duk_hthread *thr, duk_bool_t nonbmp) {
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
	duk_idx_t i, n;
	duk_ucodepoint_t cp;

	/* XXX: It would be nice to build the string directly but ToUint16()
	 * coercion is needed so a generic helper would not be very
	 * helpful (perhaps coerce the value stack first here and then
	 * build a string from a duk_tval number sequence in one go?).
	 */

	n = duk_get_top(thr);

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(thr, bw, (duk_size_t) n);  /* initial estimate for ASCII only codepoints */

	for (i = 0; i < n; i++) {
		/* XXX: could improve bufwriter handling to write multiple codepoints
		 * with one ensure call but the relative benefit would be quite small.
		 */

		if (nonbmp) {
			/* ES2015 requires that (1) SameValue(cp, ToInteger(cp)) and
			 * (2) cp >= 0 and cp <= 0x10ffff.  This check does not
			 * implement the steps exactly but the outcome should be
			 * the same.
			 */
			duk_int32_t i32 = 0;
			if (!duk_is_whole_get_int32(duk_to_number(thr, i), &i32) ||
			    i32 < 0 || i32 > 0x10ffffL) {
				DUK_DCERROR_RANGE_INVALID_ARGS(thr);
			}
			DUK_ASSERT(i32 >= 0 && i32 <= 0x10ffffL);
			cp = (duk_ucodepoint_t) i32;
			DUK_BW_WRITE_ENSURE_CESU8(thr, bw, cp);
		} else {
#if defined(DUK_USE_NONSTD_STRING_FROMCHARCODE_32BIT)
			/* ToUint16() coercion is mandatory in the E5.1 specification, but
			 * this non-compliant behavior makes more sense because we support
			 * non-BMP codepoints.  Don't use CESU-8 because that'd create
			 * surrogate pairs.
			 */
			cp = (duk_ucodepoint_t) duk_to_uint32(thr, i);
			DUK_BW_WRITE_ENSURE_XUTF8(thr, bw, cp);
#else
			cp = (duk_ucodepoint_t) duk_to_uint16(thr, i);
			DUK_ASSERT(cp >= 0 && cp <= 0x10ffffL);
			DUK_BW_WRITE_ENSURE_CESU8(thr, bw, cp);
#endif
		}
	}

	DUK_BW_COMPACT(thr, bw);
	(void) duk_buffer_to_string(thr, -1);  /* Safe, extended UTF-8 or CESU-8 encoded. */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_string_constructor_from_char_code(duk_hthread *thr) {
	return duk__construct_from_codepoints(thr, 0 /*nonbmp*/);
}

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_string_constructor_from_code_point(duk_hthread *thr) {
	return duk__construct_from_codepoints(thr, 1 /*nonbmp*/);
}
#endif

/*
 *  toString(), valueOf()
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_to_string(duk_hthread *thr) {
	duk_tval *tv;

	duk_push_this(thr);
	tv = duk_require_tval(thr, -1);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_STRING(tv)) {
		/* return as is */
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		/* Must be a "string object", i.e. class "String" */
		if (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_STRING) {
			goto type_error;
		}

		duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_VALUE);
		DUK_ASSERT(duk_is_string(thr, -1));
	} else {
		goto type_error;
	}

	(void) duk_require_hstring_notsymbol(thr, -1);  /* Reject symbols (and wrapped symbols). */
	return 1;

 type_error:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}

/*
 *  Character and charcode access
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_char_at(duk_hthread *thr) {
	duk_hstring *h;
	duk_int_t pos;

	/* XXX: faster implementation */

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);

	pos = duk_to_int(thr, 0);

	if (sizeof(duk_size_t) >= sizeof(duk_uint_t)) {
		/* Cast to duk_size_t works in this case:
		 * - If pos < 0, (duk_size_t) pos will always be
		 *   >= max_charlen, and result will be the empty string
		 *   (see duk_substring()).
		 * - If pos >= 0, pos + 1 cannot wrap.
		 */
		DUK_ASSERT((duk_size_t) DUK_INT_MIN >= DUK_HSTRING_MAX_BYTELEN);
		DUK_ASSERT((duk_size_t) DUK_INT_MAX + 1U > (duk_size_t) DUK_INT_MAX);
		duk_substring(thr, -1, (duk_size_t) pos, (duk_size_t) pos + 1U);
	} else {
		/* If size_t is smaller than int, explicit bounds checks
		 * are needed because an int may wrap multiple times.
		 */
		if (DUK_UNLIKELY(pos < 0 || (duk_uint_t) pos >= (duk_uint_t) DUK_HSTRING_GET_CHARLEN(h))) {
			duk_push_hstring_empty(thr);
		} else {
			duk_substring(thr, -1, (duk_size_t) pos, (duk_size_t) pos + 1U);
		}
	}

	return 1;
}

/* Magic: 0=charCodeAt, 1=codePointAt */
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_char_code_at(duk_hthread *thr) {
	duk_int_t pos;
	duk_hstring *h;
	duk_bool_t clamped;
	duk_uint32_t cp;
	duk_int_t magic;

	/* XXX: faster implementation */

	DUK_DDD(DUK_DDDPRINT("arg=%!T", (duk_tval *) duk_get_tval(thr, 0)));

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);

	pos = duk_to_int_clamped_raw(thr,
	                             0 /*index*/,
	                             0 /*min(incl)*/,
	                             (duk_int_t) DUK_HSTRING_GET_CHARLEN(h) - 1 /*max(incl)*/,
	                             &clamped /*out_clamped*/);
#if defined(DUK_USE_ES6)
	magic = duk_get_current_magic(thr);
#else
	DUK_ASSERT(duk_get_current_magic(thr) == 0);
	magic = 0;
#endif
	if (clamped) {
		/* For out-of-bounds indices .charCodeAt() returns NaN and
		 * .codePointAt() returns undefined.
		 */
		if (magic != 0) {
			return 0;
		}
		duk_push_nan(thr);
	} else {
		DUK_ASSERT(pos >= 0);
		cp = (duk_uint32_t) duk_hstring_char_code_at_raw(thr, h, (duk_uint_t) pos, (duk_bool_t) magic /*surrogate_aware*/);
		duk_push_u32(thr, cp);
	}
	return 1;
}

/*
 *  substring(), substr(), slice()
 */

/* XXX: any chance of merging these three similar but still slightly
 * different algorithms so that footprint would be reduced?
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_substring(duk_hthread *thr) {
	duk_hstring *h;
	duk_int_t start_pos, end_pos;
	duk_int_t len;

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);
	len = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h);

	/* [ start end str ] */

	start_pos = duk_to_int_clamped(thr, 0, 0, len);
	if (duk_is_undefined(thr, 1)) {
		end_pos = len;
	} else {
		end_pos = duk_to_int_clamped(thr, 1, 0, len);
	}
	DUK_ASSERT(start_pos >= 0 && start_pos <= len);
	DUK_ASSERT(end_pos >= 0 && end_pos <= len);

	if (start_pos > end_pos) {
		duk_int_t tmp = start_pos;
		start_pos = end_pos;
		end_pos = tmp;
	}

	DUK_ASSERT(end_pos >= start_pos);

	duk_substring(thr, -1, (duk_size_t) start_pos, (duk_size_t) end_pos);
	return 1;
}

#if defined(DUK_USE_SECTION_B)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_substr(duk_hthread *thr) {
	duk_hstring *h;
	duk_int_t start_pos, end_pos;
	duk_int_t len;

	/* Unlike non-obsolete String calls, substr() algorithm in E5.1
	 * specification will happily coerce undefined and null to strings
	 * ("undefined" and "null").
	 */
	duk_push_this(thr);
	h = duk_to_hstring_m1(thr);  /* Reject Symbols. */
	DUK_ASSERT(h != NULL);
	len = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h);

	/* [ start length str ] */

	/* The implementation for computing of start_pos and end_pos differs
	 * from the standard algorithm, but is intended to result in the exactly
	 * same behavior.  This is not always obvious.
	 */

	/* combines steps 2 and 5; -len ensures max() not needed for step 5 */
	start_pos = duk_to_int_clamped(thr, 0, -len, len);
	if (start_pos < 0) {
		start_pos = len + start_pos;
	}
	DUK_ASSERT(start_pos >= 0 && start_pos <= len);

	/* combines steps 3, 6; step 7 is not needed */
	if (duk_is_undefined(thr, 1)) {
		end_pos = len;
	} else {
		DUK_ASSERT(start_pos <= len);
		end_pos = start_pos + duk_to_int_clamped(thr, 1, 0, len - start_pos);
	}
	DUK_ASSERT(start_pos >= 0 && start_pos <= len);
	DUK_ASSERT(end_pos >= 0 && end_pos <= len);
	DUK_ASSERT(end_pos >= start_pos);

	duk_substring(thr, -1, (duk_size_t) start_pos, (duk_size_t) end_pos);
	return 1;
}
#endif  /* DUK_USE_SECTION_B */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_slice(duk_hthread *thr) {
	duk_hstring *h;
	duk_int_t start_pos, end_pos;
	duk_int_t len;

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);
	len = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h);

	/* [ start end str ] */

	start_pos = duk_to_int_clamped(thr, 0, -len, len);
	if (start_pos < 0) {
		start_pos = len + start_pos;
	}
	if (duk_is_undefined(thr, 1)) {
		end_pos = len;
	} else {
		end_pos = duk_to_int_clamped(thr, 1, -len, len);
		if (end_pos < 0) {
			end_pos = len + end_pos;
		}
	}
	DUK_ASSERT(start_pos >= 0 && start_pos <= len);
	DUK_ASSERT(end_pos >= 0 && end_pos <= len);

	if (end_pos < start_pos) {
		end_pos = start_pos;
	}

	DUK_ASSERT(end_pos >= start_pos);

	duk_substring(thr, -1, (duk_size_t) start_pos, (duk_size_t) end_pos);
	return 1;
}

/*
 *  Case conversion
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_caseconv_shared(duk_hthread *thr) {
	duk_small_int_t uppercase = duk_get_current_magic(thr);

	(void) duk_push_this_coercible_to_string(thr);
	duk_unicode_case_convert_string(thr, (duk_bool_t) uppercase);
	return 1;
}

/*
 *  indexOf() and lastIndexOf()
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_indexof_shared(duk_hthread *thr) {
	duk_hstring *h_this;
	duk_hstring *h_search;
	duk_int_t clen_this;
	duk_int_t cpos;
	duk_small_uint_t is_lastindexof = (duk_small_uint_t) duk_get_current_magic(thr);  /* 0=indexOf, 1=lastIndexOf */

	h_this = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h_this != NULL);
	clen_this = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h_this);

	h_search = duk_to_hstring(thr, 0);
	DUK_ASSERT(h_search != NULL);

	duk_to_number(thr, 1);
	if (duk_is_nan(thr, 1) && is_lastindexof) {
		/* indexOf: NaN should cause pos to be zero.
		 * lastIndexOf: NaN should cause pos to be +Infinity
		 * (and later be clamped to len).
		 */
		cpos = clen_this;
	} else {
		cpos = duk_to_int_clamped(thr, 1, 0, clen_this);
	}

	cpos = duk__str_search_shared(thr, h_this, h_search, cpos, is_lastindexof /*backwards*/);
	duk_push_int(thr, cpos);
	return 1;
}

/*
 *  replace()
 */

/* XXX: the current implementation works but is quite clunky; it compiles
 * to almost 1,4kB of x86 code so it needs to be simplified (better approach,
 * shared helpers, etc).  Some ideas for refactoring:
 *
 * - a primitive to convert a string into a regexp matcher (reduces matching
 *   code at the cost of making matching much slower)
 * - use replace() as a basic helper for match() and split(), which are both
 *   much simpler
 * - API call to get_prop and to_boolean
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_replace(duk_hthread *thr) {
	duk_hstring *h_input;
	duk_hstring *h_match;
	duk_hstring *h_search;
	duk_hobject *h_re;
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
#if defined(DUK_USE_REGEXP_SUPPORT)
	duk_bool_t is_regexp;
	duk_bool_t is_global;
#endif
	duk_bool_t is_repl_func;
	duk_uint32_t match_start_coff, match_start_boff;
#if defined(DUK_USE_REGEXP_SUPPORT)
	duk_int_t match_caps;
#endif
	duk_uint32_t prev_match_end_boff;
	const duk_uint8_t *r_start, *r_end, *r;   /* repl string scan */
	duk_size_t tmp_sz;

	DUK_ASSERT_TOP(thr, 2);
	h_input = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h_input != NULL);

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(thr, bw, DUK_HSTRING_GET_BYTELEN(h_input));  /* input size is good output starting point */

	DUK_ASSERT_TOP(thr, 4);

	/* stack[0] = search value
	 * stack[1] = replace value
	 * stack[2] = input string
	 * stack[3] = result buffer
	 */

	h_re = duk_get_hobject_with_class(thr, 0, DUK_HOBJECT_CLASS_REGEXP);
	if (h_re) {
#if defined(DUK_USE_REGEXP_SUPPORT)
		is_regexp = 1;
		is_global = duk_get_prop_stridx_boolean(thr, 0, DUK_STRIDX_GLOBAL, NULL);

		if (is_global) {
			/* start match from beginning */
			duk_push_int(thr, 0);
			duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
		}
#else  /* DUK_USE_REGEXP_SUPPORT */
		DUK_DCERROR_UNSUPPORTED(thr);
#endif  /* DUK_USE_REGEXP_SUPPORT */
	} else {
		duk_to_string(thr, 0);  /* rejects symbols */
#if defined(DUK_USE_REGEXP_SUPPORT)
		is_regexp = 0;
		is_global = 0;
#endif
	}

	if (duk_is_function(thr, 1)) {
		is_repl_func = 1;
		r_start = NULL;
		r_end = NULL;
	} else {
		duk_hstring *h_repl;

		is_repl_func = 0;
		h_repl = duk_to_hstring(thr, 1);  /* reject symbols */
		DUK_ASSERT(h_repl != NULL);
		r_start = DUK_HSTRING_GET_DATA(h_repl);
		r_end = r_start + DUK_HSTRING_GET_BYTELEN(h_repl);
	}

	prev_match_end_boff = 0;

	for (;;) {
		/*
		 *  If matching with a regexp:
		 *    - non-global RegExp: lastIndex not touched on a match, zeroed
		 *      on a non-match
		 *    - global RegExp: on match, lastIndex will be updated by regexp
		 *      executor to point to next char after the matching part (so that
		 *      characters in the matching part are not matched again)
		 *
		 *  If matching with a string:
		 *    - always non-global match, find first occurrence
		 *
		 *  We need:
		 *    - The character offset of start-of-match for the replacer function
		 *    - The byte offsets for start-of-match and end-of-match to implement
		 *      the replacement values $&, $`, and $', and to copy non-matching
		 *      input string portions (including header and trailer) verbatim.
		 *
		 *  NOTE: the E5.1 specification is a bit vague how the RegExp should
		 *  behave in the replacement process; e.g. is matching done first for
		 *  all matches (in the global RegExp case) before any replacer calls
		 *  are made?  See: test-bi-string-proto-replace.js for discussion.
		 */

		DUK_ASSERT_TOP(thr, 4);

#if defined(DUK_USE_REGEXP_SUPPORT)
		if (is_regexp) {
			duk_dup_0(thr);
			duk_dup_2(thr);
			duk_regexp_match(thr);  /* [ ... regexp input ] -> [ res_obj ] */
			if (!duk_is_object(thr, -1)) {
				duk_pop(thr);
				break;
			}

			duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_INDEX);
			DUK_ASSERT(duk_is_number(thr, -1));
			match_start_coff = duk_get_uint(thr, -1);
			duk_pop(thr);

			duk_get_prop_index(thr, -1, 0);
			DUK_ASSERT(duk_is_string(thr, -1));
			h_match = duk_known_hstring(thr, -1);
			duk_pop(thr);  /* h_match is borrowed, remains reachable through match_obj */

			if (DUK_HSTRING_GET_BYTELEN(h_match) == 0) {
				/* This should be equivalent to match() algorithm step 8.f.iii.2:
				 * detect an empty match and allow it, but don't allow it twice.
				 */
				duk_uint32_t last_index;

				duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
				last_index = (duk_uint32_t) duk_get_uint(thr, -1);
				DUK_DDD(DUK_DDDPRINT("empty match, bump lastIndex: %ld -> %ld",
				                     (long) last_index, (long) (last_index + 1)));
				duk_pop(thr);
				duk_push_uint(thr, (duk_uint_t) (last_index + 1));
				duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
			}

			DUK_ASSERT(duk_get_length(thr, -1) <= DUK_INT_MAX);  /* string limits */
			match_caps = (duk_int_t) duk_get_length(thr, -1);
		} else {
#else  /* DUK_USE_REGEXP_SUPPORT */
		{  /* unconditionally */
#endif  /* DUK_USE_REGEXP_SUPPORT */
			const duk_uint8_t *p_start, *p_end, *p;   /* input string scan */
			const duk_uint8_t *q_start;               /* match string */
			duk_size_t q_blen;

#if defined(DUK_USE_REGEXP_SUPPORT)
			DUK_ASSERT(!is_global);  /* single match always */
#endif

			p_start = DUK_HSTRING_GET_DATA(h_input);
			p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
			p = p_start;

			h_search = duk_known_hstring(thr, 0);
			q_start = DUK_HSTRING_GET_DATA(h_search);
			q_blen = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h_search);

			p_end -= q_blen;  /* ensure full memcmp() fits in while */

			match_start_coff = 0;

			while (p <= p_end) {
				DUK_ASSERT(p + q_blen <= DUK_HSTRING_GET_DATA(h_input) + DUK_HSTRING_GET_BYTELEN(h_input));
				if (duk_memcmp((const void *) p, (const void *) q_start, (size_t) q_blen) == 0) {
					duk_dup_0(thr);
					h_match = duk_known_hstring(thr, -1);
#if defined(DUK_USE_REGEXP_SUPPORT)
					match_caps = 0;
#endif
					goto found;
				}

				/* track utf-8 non-continuation bytes */
				if ((p[0] & 0xc0) != 0x80) {
					match_start_coff++;
				}
				p++;
			}

			/* not found */
			break;
		}
	 found:

		/* stack[0] = search value
		 * stack[1] = replace value
		 * stack[2] = input string
		 * stack[3] = result buffer
		 * stack[4] = regexp match OR match string
		 */

		match_start_boff = (duk_uint32_t) duk_heap_strcache_offset_char2byte(thr, h_input, match_start_coff);

		tmp_sz = (duk_size_t) (match_start_boff - prev_match_end_boff);
		DUK_BW_WRITE_ENSURE_BYTES(thr, bw, DUK_HSTRING_GET_DATA(h_input) + prev_match_end_boff, tmp_sz);

		prev_match_end_boff = match_start_boff + DUK_HSTRING_GET_BYTELEN(h_match);

		if (is_repl_func) {
			duk_idx_t idx_args;
			duk_hstring *h_repl;

			/* regexp res_obj is at index 4 */

			duk_dup_1(thr);
			idx_args = duk_get_top(thr);

#if defined(DUK_USE_REGEXP_SUPPORT)
			if (is_regexp) {
				duk_int_t idx;
				duk_require_stack(thr, match_caps + 2);
				for (idx = 0; idx < match_caps; idx++) {
					/* match followed by capture(s) */
					duk_get_prop_index(thr, 4, (duk_uarridx_t) idx);
				}
			} else {
#else  /* DUK_USE_REGEXP_SUPPORT */
			{  /* unconditionally */
#endif  /* DUK_USE_REGEXP_SUPPORT */
				/* match == search string, by definition */
				duk_dup_0(thr);
			}
			duk_push_uint(thr, (duk_uint_t) match_start_coff);
			duk_dup_2(thr);

			/* [ ... replacer match [captures] match_char_offset input ] */

			duk_call(thr, duk_get_top(thr) - idx_args);
			h_repl = duk_to_hstring_m1(thr);  /* -> [ ... repl_value ] */
			DUK_ASSERT(h_repl != NULL);

			DUK_BW_WRITE_ENSURE_HSTRING(thr, bw, h_repl);

			duk_pop(thr);  /* repl_value */
		} else {
			r = r_start;

			while (r < r_end) {
				duk_int_t ch1;
				duk_int_t ch2;
#if defined(DUK_USE_REGEXP_SUPPORT)
				duk_int_t ch3;
#endif
				duk_size_t left;

				ch1 = *r++;
				if (ch1 != DUK_ASC_DOLLAR) {
					goto repl_write;
				}
				DUK_ASSERT(r <= r_end);
				left = (duk_size_t) (r_end - r);

				if (left <= 0) {
					goto repl_write;
				}

				ch2 = r[0];
				switch (ch2) {
				case DUK_ASC_DOLLAR: {
					ch1 = (1 << 8) + DUK_ASC_DOLLAR;
					goto repl_write;
				}
				case DUK_ASC_AMP: {
					DUK_BW_WRITE_ENSURE_HSTRING(thr, bw, h_match);
					r++;
					continue;
				}
				case DUK_ASC_GRAVE: {
					tmp_sz = (duk_size_t) match_start_boff;
					DUK_BW_WRITE_ENSURE_BYTES(thr, bw, DUK_HSTRING_GET_DATA(h_input), tmp_sz);
					r++;
					continue;
				}
				case DUK_ASC_SINGLEQUOTE: {
					duk_uint32_t match_end_boff;

					/* Use match charlen instead of bytelen, just in case the input and
					 * match codepoint encodings would have different lengths.
					 */
					/* XXX: charlen computed here, and also in char2byte helper. */
					match_end_boff = (duk_uint32_t) duk_heap_strcache_offset_char2byte(thr,
					                                                                   h_input,
					                                                                   match_start_coff + (duk_uint_fast32_t) DUK_HSTRING_GET_CHARLEN(h_match));

					tmp_sz = (duk_size_t) (DUK_HSTRING_GET_BYTELEN(h_input) - match_end_boff);
					DUK_BW_WRITE_ENSURE_BYTES(thr, bw, DUK_HSTRING_GET_DATA(h_input) + match_end_boff, tmp_sz);
					r++;
					continue;
				}
				default: {
#if defined(DUK_USE_REGEXP_SUPPORT)
					duk_int_t capnum, captmp, capadv;
					/* XXX: optional check, match_caps is zero if no regexp,
					 * so dollar will be interpreted literally anyway.
					 */

					if (!is_regexp) {
						goto repl_write;
					}

					if (!(ch2 >= DUK_ASC_0 && ch2 <= DUK_ASC_9)) {
						goto repl_write;
					}
					capnum = ch2 - DUK_ASC_0;
					capadv = 1;

					if (left >= 2) {
						ch3 = r[1];
						if (ch3 >= DUK_ASC_0 && ch3 <= DUK_ASC_9) {
							captmp = capnum * 10 + (ch3 - DUK_ASC_0);
							if (captmp < match_caps) {
								capnum = captmp;
								capadv = 2;
							}
						}
					}

					if (capnum > 0 && capnum < match_caps) {
						DUK_ASSERT(is_regexp != 0);  /* match_caps == 0 without regexps */

						/* regexp res_obj is at offset 4 */
						duk_get_prop_index(thr, 4, (duk_uarridx_t) capnum);
						if (duk_is_string(thr, -1)) {
							duk_hstring *h_tmp_str;

							h_tmp_str = duk_known_hstring(thr, -1);

							DUK_BW_WRITE_ENSURE_HSTRING(thr, bw, h_tmp_str);
						} else {
							/* undefined -> skip (replaced with empty) */
						}
						duk_pop(thr);
						r += capadv;
						continue;
					} else {
						goto repl_write;
					}
#else  /* DUK_USE_REGEXP_SUPPORT */
					goto repl_write;  /* unconditionally */
#endif  /* DUK_USE_REGEXP_SUPPORT */
				}  /* default case */
				}  /* switch (ch2) */

			 repl_write:
				/* ch1 = (r_increment << 8) + byte */

				DUK_BW_WRITE_ENSURE_U8(thr, bw, (duk_uint8_t) (ch1 & 0xff));
				r += ch1 >> 8;
			}  /* while repl */
		}  /* if (is_repl_func) */

		duk_pop(thr);  /* pop regexp res_obj or match string */

#if defined(DUK_USE_REGEXP_SUPPORT)
		if (!is_global) {
#else
		{  /* unconditionally; is_global==0 */
#endif
			break;
		}
	}

	/* trailer */
	tmp_sz = (duk_size_t) (DUK_HSTRING_GET_BYTELEN(h_input) - prev_match_end_boff);
	DUK_BW_WRITE_ENSURE_BYTES(thr, bw, DUK_HSTRING_GET_DATA(h_input) + prev_match_end_boff, tmp_sz);

	DUK_ASSERT_TOP(thr, 4);
	DUK_BW_COMPACT(thr, bw);
	(void) duk_buffer_to_string(thr, -1);  /* Safe if inputs are safe. */
	return 1;
}

/*
 *  split()
 */

/* XXX: very messy now, but works; clean up, remove unused variables (nomimally
 * used so compiler doesn't complain).
 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_split(duk_hthread *thr) {
	duk_hstring *h_input;
	duk_hstring *h_sep;
	duk_uint32_t limit;
	duk_uint32_t arr_idx;
#if defined(DUK_USE_REGEXP_SUPPORT)
	duk_bool_t is_regexp;
#endif
	duk_bool_t matched;  /* set to 1 if any match exists (needed for empty input special case) */
	duk_uint32_t prev_match_end_coff, prev_match_end_boff;
	duk_uint32_t match_start_boff, match_start_coff;
	duk_uint32_t match_end_boff, match_end_coff;

	h_input = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h_input != NULL);

	duk_push_array(thr);

	if (duk_is_undefined(thr, 1)) {
		limit = 0xffffffffUL;
	} else {
		limit = duk_to_uint32(thr, 1);
	}

	if (limit == 0) {
		return 1;
	}

	/* If the separator is a RegExp, make a "clone" of it.  The specification
	 * algorithm calls [[Match]] directly for specific indices; we emulate this
	 * by tweaking lastIndex and using a "force global" variant of duk_regexp_match()
	 * which will use global-style matching even when the RegExp itself is non-global.
	 */

	if (duk_is_undefined(thr, 0)) {
		/* The spec algorithm first does "R = ToString(separator)" before checking
		 * whether separator is undefined.  Since this is side effect free, we can
		 * skip the ToString() here.
		 */
		duk_dup_2(thr);
		duk_put_prop_index(thr, 3, 0);
		return 1;
	} else if (duk_get_hobject_with_class(thr, 0, DUK_HOBJECT_CLASS_REGEXP) != NULL) {
#if defined(DUK_USE_REGEXP_SUPPORT)
		duk_push_hobject_bidx(thr, DUK_BIDX_REGEXP_CONSTRUCTOR);
		duk_dup_0(thr);
		duk_new(thr, 1);  /* [ ... RegExp val ] -> [ ... res ] */
		duk_replace(thr, 0);
		/* lastIndex is initialized to zero by new RegExp() */
		is_regexp = 1;
#else
		DUK_DCERROR_UNSUPPORTED(thr);
#endif
	} else {
		duk_to_string(thr, 0);
#if defined(DUK_USE_REGEXP_SUPPORT)
		is_regexp = 0;
#endif
	}

	/* stack[0] = separator (string or regexp)
	 * stack[1] = limit
	 * stack[2] = input string
	 * stack[3] = result array
	 */

	prev_match_end_boff = 0;
	prev_match_end_coff = 0;
	arr_idx = 0;
	matched = 0;

	for (;;) {
		/*
		 *  The specification uses RegExp [[Match]] to attempt match at specific
		 *  offsets.  We don't have such a primitive, so we use an actual RegExp
		 *  and tweak lastIndex.  Since the RegExp may be non-global, we use a
		 *  special variant which forces global-like behavior for matching.
		 */

		DUK_ASSERT_TOP(thr, 4);

#if defined(DUK_USE_REGEXP_SUPPORT)
		if (is_regexp) {
			duk_dup_0(thr);
			duk_dup_2(thr);
			duk_regexp_match_force_global(thr);  /* [ ... regexp input ] -> [ res_obj ] */
			if (!duk_is_object(thr, -1)) {
				duk_pop(thr);
				break;
			}
			matched = 1;

			duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_INDEX);
			DUK_ASSERT(duk_is_number(thr, -1));
			match_start_coff = duk_get_uint(thr, -1);
			match_start_boff = (duk_uint32_t) duk_heap_strcache_offset_char2byte(thr, h_input, match_start_coff);
			duk_pop(thr);

			if (match_start_coff == DUK_HSTRING_GET_CHARLEN(h_input)) {
				/* don't allow an empty match at the end of the string */
				duk_pop(thr);
				break;
			}

			duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
			DUK_ASSERT(duk_is_number(thr, -1));
			match_end_coff = duk_get_uint(thr, -1);
			match_end_boff = (duk_uint32_t) duk_heap_strcache_offset_char2byte(thr, h_input, match_end_coff);
			duk_pop(thr);

			/* empty match -> bump and continue */
			if (prev_match_end_boff == match_end_boff) {
				duk_push_uint(thr, (duk_uint_t) (match_end_coff + 1));
				duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
				duk_pop(thr);
				continue;
			}
		} else {
#else  /* DUK_USE_REGEXP_SUPPORT */
		{  /* unconditionally */
#endif  /* DUK_USE_REGEXP_SUPPORT */
			const duk_uint8_t *p_start, *p_end, *p;   /* input string scan */
			const duk_uint8_t *q_start;               /* match string */
			duk_size_t q_blen, q_clen;

			p_start = DUK_HSTRING_GET_DATA(h_input);
			p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
			p = p_start + prev_match_end_boff;

			h_sep = duk_known_hstring(thr, 0);  /* symbol already rejected above */
			q_start = DUK_HSTRING_GET_DATA(h_sep);
			q_blen = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h_sep);
			q_clen = (duk_size_t) DUK_HSTRING_GET_CHARLEN(h_sep);

			p_end -= q_blen;  /* ensure full memcmp() fits in while */

			match_start_coff = prev_match_end_coff;

			if (q_blen == 0) {
				/* Handle empty separator case: it will always match, and always
				 * triggers the check in step 13.c.iii initially.  Note that we
				 * must skip to either end of string or start of first codepoint,
				 * skipping over any continuation bytes!
				 *
				 * Don't allow an empty string to match at the end of the input.
				 */

				matched = 1;  /* empty separator can always match */

				match_start_coff++;
				p++;
				while (p < p_end) {
					if ((p[0] & 0xc0) != 0x80) {
						goto found;
					}
					p++;
				}
				goto not_found;
			}

			DUK_ASSERT(q_blen > 0 && q_clen > 0);
			while (p <= p_end) {
				DUK_ASSERT(p + q_blen <= DUK_HSTRING_GET_DATA(h_input) + DUK_HSTRING_GET_BYTELEN(h_input));
				DUK_ASSERT(q_blen > 0);  /* no issues with empty memcmp() */
				if (duk_memcmp((const void *) p, (const void *) q_start, (size_t) q_blen) == 0) {
					/* never an empty match, so step 13.c.iii can't be triggered */
					goto found;
				}

				/* track utf-8 non-continuation bytes */
				if ((p[0] & 0xc0) != 0x80) {
					match_start_coff++;
				}
				p++;
			}

		 not_found:
			/* not found */
			break;

		 found:
			matched = 1;
			match_start_boff = (duk_uint32_t) (p - p_start);
			match_end_coff = (duk_uint32_t) (match_start_coff + q_clen);  /* constrained by string length */
			match_end_boff = (duk_uint32_t) (match_start_boff + q_blen);  /* ditto */

			/* empty match (may happen with empty separator) -> bump and continue */
			if (prev_match_end_boff == match_end_boff) {
				prev_match_end_boff++;
				prev_match_end_coff++;
				continue;
			}
		}  /* if (is_regexp) */

		/* stack[0] = separator (string or regexp)
		 * stack[1] = limit
		 * stack[2] = input string
		 * stack[3] = result array
		 * stack[4] = regexp res_obj (if is_regexp)
		 */

		DUK_DDD(DUK_DDDPRINT("split; match_start b=%ld,c=%ld, match_end b=%ld,c=%ld, prev_end b=%ld,c=%ld",
		                     (long) match_start_boff, (long) match_start_coff,
		                     (long) match_end_boff, (long) match_end_coff,
		                     (long) prev_match_end_boff, (long) prev_match_end_coff));

		duk_push_lstring(thr,
		                 (const char *) (DUK_HSTRING_GET_DATA(h_input) + prev_match_end_boff),
		                 (duk_size_t) (match_start_boff - prev_match_end_boff));
		duk_put_prop_index(thr, 3, arr_idx);
		arr_idx++;
		if (arr_idx >= limit) {
			goto hit_limit;
		}

#if defined(DUK_USE_REGEXP_SUPPORT)
		if (is_regexp) {
			duk_size_t i, len;

			len = duk_get_length(thr, 4);
			for (i = 1; i < len; i++) {
				DUK_ASSERT(i <= DUK_UARRIDX_MAX);  /* cannot have >4G captures */
				duk_get_prop_index(thr, 4, (duk_uarridx_t) i);
				duk_put_prop_index(thr, 3, arr_idx);
				arr_idx++;
				if (arr_idx >= limit) {
					goto hit_limit;
				}
			}

			duk_pop(thr);
			/* lastIndex already set up for next match */
		} else {
#else  /* DUK_USE_REGEXP_SUPPORT */
		{  /* unconditionally */
#endif  /* DUK_USE_REGEXP_SUPPORT */
			/* no action */
		}

		prev_match_end_boff = match_end_boff;
		prev_match_end_coff = match_end_coff;
		continue;
	}  /* for */

	/* Combined step 11 (empty string special case) and 14-15. */

	DUK_DDD(DUK_DDDPRINT("split trailer; prev_end b=%ld,c=%ld",
	                     (long) prev_match_end_boff, (long) prev_match_end_coff));

	if (DUK_HSTRING_GET_BYTELEN(h_input) > 0 || !matched) {
		/* Add trailer if:
		 *   a) non-empty input
		 *   b) empty input and no (zero size) match found (step 11)
		 */

		duk_push_lstring(thr,
		                 (const char *) DUK_HSTRING_GET_DATA(h_input) + prev_match_end_boff,
		                 (duk_size_t) (DUK_HSTRING_GET_BYTELEN(h_input) - prev_match_end_boff));
		duk_put_prop_index(thr, 3, arr_idx);
		/* No arr_idx update or limit check */
	}

	return 1;

 hit_limit:
#if defined(DUK_USE_REGEXP_SUPPORT)
	if (is_regexp) {
		duk_pop(thr);
	}
#endif

	return 1;
}

/*
 *  Various
 */

#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_LOCAL void duk__to_regexp_helper(duk_hthread *thr, duk_idx_t idx, duk_bool_t force_new) {
	duk_hobject *h;

	/* Shared helper for match() steps 3-4, search() steps 3-4. */

	DUK_ASSERT(idx >= 0);

	if (force_new) {
		goto do_new;
	}

	h = duk_get_hobject_with_class(thr, idx, DUK_HOBJECT_CLASS_REGEXP);
	if (!h) {
		goto do_new;
	}
	return;

 do_new:
	duk_push_hobject_bidx(thr, DUK_BIDX_REGEXP_CONSTRUCTOR);
	duk_dup(thr, idx);
	duk_new(thr, 1);  /* [ ... RegExp val ] -> [ ... res ] */
	duk_replace(thr, idx);
}
#endif  /* DUK_USE_REGEXP_SUPPORT */

#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_search(duk_hthread *thr) {
	/* Easiest way to implement the search required by the specification
	 * is to do a RegExp test() with lastIndex forced to zero.  To avoid
	 * side effects on the argument, "clone" the RegExp if a RegExp was
	 * given as input.
	 *
	 * The global flag of the RegExp should be ignored; setting lastIndex
	 * to zero (which happens when "cloning" the RegExp) should have an
	 * equivalent effect.
	 */

	DUK_ASSERT_TOP(thr, 1);
	(void) duk_push_this_coercible_to_string(thr);  /* at index 1 */
	duk__to_regexp_helper(thr, 0 /*index*/, 1 /*force_new*/);

	/* stack[0] = regexp
	 * stack[1] = string
	 */

	/* Avoid using RegExp.prototype methods, as they're writable and
	 * configurable and may have been changed.
	 */

	duk_dup_0(thr);
	duk_dup_1(thr);  /* [ ... re_obj input ] */
	duk_regexp_match(thr);  /* -> [ ... res_obj ] */

	if (!duk_is_object(thr, -1)) {
		duk_push_int(thr, -1);
		return 1;
	}

	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_INDEX);
	DUK_ASSERT(duk_is_number(thr, -1));
	return 1;
}
#endif  /* DUK_USE_REGEXP_SUPPORT */

#if defined(DUK_USE_REGEXP_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_match(duk_hthread *thr) {
	duk_bool_t global;
	duk_int_t prev_last_index;
	duk_int_t this_index;
	duk_int_t arr_idx;

	DUK_ASSERT_TOP(thr, 1);
	(void) duk_push_this_coercible_to_string(thr);
	duk__to_regexp_helper(thr, 0 /*index*/, 0 /*force_new*/);
	global = duk_get_prop_stridx_boolean(thr, 0, DUK_STRIDX_GLOBAL, NULL);
	DUK_ASSERT_TOP(thr, 2);

	/* stack[0] = regexp
	 * stack[1] = string
	 */

	if (!global) {
		duk_regexp_match(thr);  /* -> [ res_obj ] */
		return 1;  /* return 'res_obj' */
	}

	/* Global case is more complex. */

	/* [ regexp string ] */

	duk_push_int(thr, 0);
	duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
	duk_push_array(thr);

	/* [ regexp string res_arr ] */

	prev_last_index = 0;
	arr_idx = 0;

	for (;;) {
		DUK_ASSERT_TOP(thr, 3);

		duk_dup_0(thr);
		duk_dup_1(thr);
		duk_regexp_match(thr);  /* -> [ ... regexp string ] -> [ ... res_obj ] */

		if (!duk_is_object(thr, -1)) {
			duk_pop(thr);
			break;
		}

		duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
		DUK_ASSERT(duk_is_number(thr, -1));
		this_index = duk_get_int(thr, -1);
		duk_pop(thr);

		if (this_index == prev_last_index) {
			this_index++;
			duk_push_int(thr, this_index);
			duk_put_prop_stridx_short(thr, 0, DUK_STRIDX_LAST_INDEX);
		}
		prev_last_index = this_index;

		duk_get_prop_index(thr, -1, 0);  /* match string */
		duk_put_prop_index(thr, 2, (duk_uarridx_t) arr_idx);
		arr_idx++;
		duk_pop(thr);  /* res_obj */
	}

	if (arr_idx == 0) {
		duk_push_null(thr);
	}

	return 1;  /* return 'res_arr' or 'null' */
}
#endif  /* DUK_USE_REGEXP_SUPPORT */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_concat(duk_hthread *thr) {
	/* duk_concat() coerces arguments with ToString() in correct order */
	(void) duk_push_this_coercible_to_string(thr);
	duk_insert(thr, 0);  /* this is relatively expensive */
	duk_concat(thr, duk_get_top(thr));
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_trim(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 0);
	(void) duk_push_this_coercible_to_string(thr);
	duk_trim(thr, 0);
	DUK_ASSERT_TOP(thr, 1);
	return 1;
}

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_repeat(duk_hthread *thr) {
	duk_hstring *h_input;
	duk_size_t input_blen;
	duk_size_t result_len;
	duk_int_t count_signed;
	duk_uint_t count;
	const duk_uint8_t *src;
	duk_uint8_t *buf;
	duk_uint8_t *p;
	duk_double_t d;
#if !defined(DUK_USE_PREFER_SIZE)
	duk_size_t copy_size;
	duk_uint8_t *p_end;
#endif

	DUK_ASSERT_TOP(thr, 1);
	h_input = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h_input != NULL);
	input_blen = DUK_HSTRING_GET_BYTELEN(h_input);

	/* Count is ToNumber() coerced; +Infinity must be always rejected
	 * (even if input string is zero length), as well as negative values
	 * and -Infinity.  -Infinity doesn't require an explicit check
	 * because duk_get_int() clamps it to DUK_INT_MIN which gets rejected
	 * as a negative value (regardless of input string length).
	 */
	d = duk_to_number(thr, 0);
	if (duk_double_is_posinf(d)) {
		goto fail_range;
	}
	count_signed = duk_get_int(thr, 0);
	if (count_signed < 0) {
		goto fail_range;
	}
	count = (duk_uint_t) count_signed;

	/* Overflow check for result length. */
	result_len = count * input_blen;
	if (count != 0 && result_len / count != input_blen) {
		goto fail_range;
	}

	/* Temporary fixed buffer, later converted to string. */
	buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, result_len);
	DUK_ASSERT(buf != NULL);
	src = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	DUK_ASSERT(src != NULL);

#if defined(DUK_USE_PREFER_SIZE)
	p = buf;
	while (count-- > 0) {
		duk_memcpy((void *) p, (const void *) src, input_blen);  /* copy size may be zero, but pointers are valid */
		p += input_blen;
	}
#else  /* DUK_USE_PREFER_SIZE */
	/* Take advantage of already copied pieces to speed up the process
	 * especially for small repeated strings.
	 */
	p = buf;
	p_end = p + result_len;
	copy_size = input_blen;
	for (;;) {
		duk_size_t remain = (duk_size_t) (p_end - p);
		DUK_DDD(DUK_DDDPRINT("remain=%ld, copy_size=%ld, input_blen=%ld, result_len=%ld",
		                     (long) remain, (long) copy_size, (long) input_blen,
		                     (long) result_len));
		if (remain <= copy_size) {
			/* If result_len is zero, this case is taken and does
			 * a zero size copy (with valid pointers).
			 */
			duk_memcpy((void *) p, (const void *) src, remain);
			break;
		} else {
			duk_memcpy((void *) p, (const void *) src, copy_size);
			p += copy_size;
		}

		src = (const duk_uint8_t *) buf;  /* Use buf as source for larger copies. */
		copy_size = (duk_size_t) (p - buf);
	}
#endif  /* DUK_USE_PREFER_SIZE */

	/* XXX: It would be useful to be able to create a duk_hstring with
	 * a certain byte size whose data area wasn't initialized and which
	 * wasn't in the string table yet.  This would allow a string to be
	 * constructed directly without a buffer temporary and when it was
	 * finished, it could be injected into the string table.  Currently
	 * this isn't possible because duk_hstrings are only tracked by the
	 * intern table (they are not in heap_allocated).
	 */

	duk_buffer_to_string(thr, -1);  /* Safe if input is safe. */
	return 1;

 fail_range:
	DUK_DCERROR_RANGE_INVALID_ARGS(thr);
}
#endif  /* DUK_USE_ES6 */

DUK_INTERNAL duk_ret_t duk_bi_string_prototype_locale_compare(duk_hthread *thr) {
	duk_hstring *h1;
	duk_hstring *h2;
	duk_size_t h1_len, h2_len, prefix_len;
	duk_small_int_t ret = 0;
	duk_small_int_t rc;

	/* The current implementation of localeCompare() is simply a codepoint
	 * by codepoint comparison, implemented with a simple string compare
	 * because UTF-8 should preserve codepoint ordering (assuming valid
	 * shortest UTF-8 encoding).
	 *
	 * The specification requires that the return value must be related
	 * to the sort order: e.g. negative means that 'this' comes before
	 * 'that' in sort order.  We assume an ascending sort order.
	 */

	/* XXX: could share code with duk_js_ops.c, duk_js_compare_helper */

	h1 = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h1 != NULL);

	h2 = duk_to_hstring(thr, 0);
	DUK_ASSERT(h2 != NULL);

	h1_len = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h1);
	h2_len = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h2);
	prefix_len = (h1_len <= h2_len ? h1_len : h2_len);

	rc = (duk_small_int_t) duk_memcmp((const void *) DUK_HSTRING_GET_DATA(h1),
	                                  (const void *) DUK_HSTRING_GET_DATA(h2),
	                                  (size_t) prefix_len);

	if (rc < 0) {
		ret = -1;
		goto done;
	} else if (rc > 0) {
		ret = 1;
		goto done;
	}

	/* prefix matches, lengths matter now */
	if (h1_len > h2_len) {
		ret = 1;
		goto done;
	} else if (h1_len == h2_len) {
		DUK_ASSERT(ret == 0);
		goto done;
	}
	ret = -1;
	goto done;

 done:
	duk_push_int(thr, (duk_int_t) ret);
	return 1;
}

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_startswith_endswith(duk_hthread *thr) {
	duk_int_t magic;
	duk_hstring *h;
	duk_hstring *h_search;
	duk_size_t blen_search;
	const duk_uint8_t *p_cmp_start;
	duk_bool_t result;

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);

	h_search = duk__str_tostring_notregexp(thr, 0);
	DUK_ASSERT(h_search != NULL);

	magic = duk_get_current_magic(thr);

	p_cmp_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	blen_search = DUK_HSTRING_GET_BYTELEN(h_search);

	if (duk_is_undefined(thr, 1)) {
		if (magic) {
			p_cmp_start = p_cmp_start + DUK_HSTRING_GET_BYTELEN(h) - blen_search;
		} else {
			/* p_cmp_start already OK */
		}
	} else {
		duk_int_t len;
		duk_int_t pos;

		DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= DUK_INT_MAX);
		len = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h);
		pos = duk_to_int_clamped(thr, 1, 0, len);
		DUK_ASSERT(pos >= 0 && pos <= len);

		if (magic) {
			p_cmp_start -= blen_search;  /* Conceptually subtracted last, but do already here. */
		}
		DUK_ASSERT(pos >= 0 && pos <= len);

		p_cmp_start += duk_heap_strcache_offset_char2byte(thr, h, (duk_uint_fast32_t) pos);
	}

	/* The main comparison can be done using a memcmp() rather than
	 * doing codepoint comparisons: for CESU-8 strings there is a
	 * canonical representation for every codepoint.  But we do need
	 * to deal with the char/byte offset translation to find the
	 * comparison range.
	 */

	result = 0;
	if (p_cmp_start >= DUK_HSTRING_GET_DATA(h) &&
	    (duk_size_t) (p_cmp_start - (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h)) + blen_search <= DUK_HSTRING_GET_BYTELEN(h)) {
		if (duk_memcmp((const void *) p_cmp_start,
		               (const void *) DUK_HSTRING_GET_DATA(h_search),
		               (size_t) blen_search) == 0) {
			result = 1;
		}
	}

	duk_push_boolean(thr, result);
	return 1;
}
#endif  /* DUK_USE_ES6 */

#if defined(DUK_USE_ES6)
DUK_INTERNAL duk_ret_t duk_bi_string_prototype_includes(duk_hthread *thr) {
	duk_hstring *h;
	duk_hstring *h_search;
	duk_int_t len;
	duk_int_t pos;

	h = duk_push_this_coercible_to_string(thr);
	DUK_ASSERT(h != NULL);

	h_search = duk__str_tostring_notregexp(thr, 0);
	DUK_ASSERT(h_search != NULL);

	len = (duk_int_t) DUK_HSTRING_GET_CHARLEN(h);
	pos = duk_to_int_clamped(thr, 1, 0, len);
	DUK_ASSERT(pos >= 0 && pos <= len);

	pos = duk__str_search_shared(thr, h, h_search, pos, 0 /*backwards*/);
	duk_push_boolean(thr, pos >= 0);
	return 1;
}
#endif  /* DUK_USE_ES6 */
#endif  /* DUK_USE_STRING_BUILTIN */
/*
 *  Symbol built-in
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_SYMBOL_BUILTIN)

/*
 *  Constructor
 */

DUK_INTERNAL duk_ret_t duk_bi_symbol_constructor_shared(duk_hthread *thr) {
	const duk_uint8_t *desc;
	duk_size_t len;
	duk_uint8_t *buf;
	duk_uint8_t *p;
	duk_int_t magic;

	magic = duk_get_current_magic(thr);
	if (duk_is_undefined(thr, 0) && (magic == 0)) {
		/* Symbol() accepts undefined and empty string, but they are
		 * treated differently.
		 */
		desc = NULL;
		len = 0;
	} else {
		/* Symbol.for() coerces undefined to 'undefined' */
		desc = (const duk_uint8_t *) duk_to_lstring(thr, 0, &len);
	}

	/* Maximum symbol data length:
	 *   +1    initial byte (0x80 or 0x81)
	 *   +len  description
	 *   +1    0xff after description, before unique suffix
	 *   +17   autogenerated unique suffix: 'ffffffff-ffffffff' is longest
	 *   +1    0xff after unique suffix for symbols with undefined description
	 */
	buf = (duk_uint8_t *) duk_push_fixed_buffer(thr, 1 + len + 1 + 17 + 1);
	DUK_ASSERT(buf != NULL);
	p = buf + 1;
	DUK_ASSERT(desc != NULL || len == 0);  /* may be NULL if len is 0 */
	duk_memcpy_unsafe((void *) p, (const void *) desc, len);
	p += len;
	if (magic == 0) {
		/* Symbol(): create unique symbol.  Use two 32-bit values
		 * to avoid dependency on 64-bit types and 64-bit integer
		 * formatting (at least for now).
		 */
		if (++thr->heap->sym_counter[0] == 0) {
			thr->heap->sym_counter[1]++;
		}
		p += DUK_SPRINTF((char *) p, "\xFF" "%lx-%lx",
		                 (unsigned long) thr->heap->sym_counter[1],
		                 (unsigned long) thr->heap->sym_counter[0]);
		if (desc == NULL) {
			/* Special case for 'undefined' description, trailing
			 * 0xff distinguishes from empty string description,
			 * but needs minimal special case handling elsewhere.
			 */
			*p++ = 0xff;
		}
		buf[0] = 0x81;
	} else {
		/* Symbol.for(): create a global symbol */
		buf[0] = 0x80;
	}

	duk_push_lstring(thr, (const char *) buf, (duk_size_t) (p - buf));
	DUK_DDD(DUK_DDDPRINT("created symbol: %!T", duk_get_tval(thr, -1)));
	return 1;
}

DUK_LOCAL duk_hstring *duk__auto_unbox_symbol(duk_hthread *thr, duk_tval *tv_arg) {
	duk_tval *tv;
	duk_hobject *h_obj;
	duk_hstring *h_str;

	DUK_ASSERT(tv_arg != NULL);

	/* XXX: add internal helper: duk_auto_unbox_tval(thr, tv, mask); */
	/* XXX: add internal helper: duk_auto_unbox(thr, tv, idx); */

	tv = tv_arg;
	if (DUK_TVAL_IS_OBJECT(tv)) {
		h_obj = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h_obj != NULL);
		if (DUK_HOBJECT_GET_CLASS_NUMBER(h_obj) == DUK_HOBJECT_CLASS_SYMBOL) {
			tv = duk_hobject_get_internal_value_tval_ptr(thr->heap, h_obj);
			if (tv == NULL) {
				return NULL;
			}
		} else {
			return NULL;
		}
	}

	if (!DUK_TVAL_IS_STRING(tv)) {
		return NULL;
	}
	h_str = DUK_TVAL_GET_STRING(tv);
	DUK_ASSERT(h_str != NULL);

	/* Here symbol is more expected than not. */
	if (DUK_UNLIKELY(!DUK_HSTRING_HAS_SYMBOL(h_str))) {
		return NULL;
	}

	return h_str;
}

DUK_INTERNAL duk_ret_t duk_bi_symbol_tostring_shared(duk_hthread *thr) {
	duk_hstring *h_str;

	h_str = duk__auto_unbox_symbol(thr, DUK_HTHREAD_THIS_PTR(thr));
	if (h_str == NULL) {
		return DUK_RET_TYPE_ERROR;
	}

	if (duk_get_current_magic(thr) == 0) {
		/* .toString() */
		duk_push_symbol_descriptive_string(thr, h_str);
	} else {
		/* .valueOf() */
		duk_push_hstring(thr, h_str);
	}
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_symbol_key_for(duk_hthread *thr) {
	duk_hstring *h;
	const duk_uint8_t *p;

	/* Argument must be a symbol but not checked here.  The initial byte
	 * check will catch non-symbol strings.
	 */
	h = duk_require_hstring(thr, 0);
	DUK_ASSERT(h != NULL);

	p = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	DUK_ASSERT(p != NULL);

	/* Even for zero length strings there's at least one NUL byte so
	 * we can safely check the initial byte.
	 */
	if (p[0] == 0x80) {
		/* Global symbol, return its key (bytes just after the initial byte). */
		duk_push_lstring(thr, (const char *) (p + 1), (duk_size_t) (DUK_HSTRING_GET_BYTELEN(h) - 1));
		return 1;
	} else if (p[0] == 0x81 || p[0] == 0x82 || p[0] == 0xff) {
		/* Local symbol or hidden symbol, return undefined. */
		return 0;
	}

	/* Covers normal strings and unknown initial bytes. */
	return DUK_RET_TYPE_ERROR;
}

DUK_INTERNAL duk_ret_t duk_bi_symbol_toprimitive(duk_hthread *thr) {
	duk_hstring *h_str;

	h_str = duk__auto_unbox_symbol(thr, DUK_HTHREAD_THIS_PTR(thr));
	if (h_str == NULL) {
		return DUK_RET_TYPE_ERROR;
	}
	duk_push_hstring(thr, h_str);
	return 1;
}

#endif  /* DUK_USE_SYMBOL_BUILTIN */
/*
 *  Thread builtins
 */

/* #include duk_internal.h -> already included */

/*
 *  Constructor
 */

#if defined(DUK_USE_COROUTINE_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_thread_constructor(duk_hthread *thr) {
	duk_hthread *new_thr;
	duk_hobject *func;

	/* Check that the argument is callable; this is not 100% because we
	 * don't allow native functions to be a thread's initial function.
	 * Resume will reject such functions in any case.
	 */
	/* XXX: need a duk_require_func_promote_lfunc() */
	func = duk_require_hobject_promote_lfunc(thr, 0);
	DUK_ASSERT(func != NULL);
	duk_require_callable(thr, 0);

	duk_push_thread(thr);
	new_thr = (duk_hthread *) duk_known_hobject(thr, -1);
	new_thr->state = DUK_HTHREAD_STATE_INACTIVE;

	/* push initial function call to new thread stack; this is
	 * picked up by resume().
	 */
	duk_push_hobject(new_thr, func);

	return 1;  /* return thread */
}
#endif

/*
 *  Resume a thread.
 *
 *  The thread must be in resumable state, either (a) new thread which hasn't
 *  yet started, or (b) a thread which has previously yielded.  This method
 *  must be called from an ECMAScript function.
 *
 *  Args:
 *    - thread
 *    - value
 *    - isError (defaults to false)
 *
 *  Note: yield and resume handling is currently asymmetric.
 */

#if defined(DUK_USE_COROUTINE_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_thread_resume(duk_hthread *ctx) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_hthread *thr_resume;
	duk_hobject *caller_func;
	duk_small_uint_t is_error;

	DUK_DDD(DUK_DDDPRINT("Duktape.Thread.resume(): thread=%!T, value=%!T, is_error=%!T",
	                     (duk_tval *) duk_get_tval(thr, 0),
	                     (duk_tval *) duk_get_tval(thr, 1),
	                     (duk_tval *) duk_get_tval(thr, 2)));

	DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
	DUK_ASSERT(thr->heap->curr_thread == thr);

	thr_resume = duk_require_hthread(thr, 0);
	DUK_ASSERT(duk_get_top(thr) == 3);
	is_error = (duk_small_uint_t) duk_to_boolean_top_pop(thr);
	DUK_ASSERT(duk_get_top(thr) == 2);

	/* [ thread value ] */

	/*
	 *  Thread state and calling context checks
	 */

	if (thr->callstack_top < 2) {
		DUK_DD(DUK_DDPRINT("resume state invalid: callstack should contain at least 2 entries (caller and Duktape.Thread.resume)"));
		goto state_error;
	}
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(thr->callstack_curr->parent != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);  /* us */
	DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr->parent) != NULL);  /* caller */

	caller_func = DUK_ACT_GET_FUNC(thr->callstack_curr->parent);
	if (!DUK_HOBJECT_IS_COMPFUNC(caller_func)) {
		DUK_DD(DUK_DDPRINT("resume state invalid: caller must be ECMAScript code"));
		goto state_error;
	}

	/* Note: there is no requirement that: 'thr->callstack_preventcount == 1'
	 * like for yield.
	 */

	if (thr_resume->state != DUK_HTHREAD_STATE_INACTIVE &&
	    thr_resume->state != DUK_HTHREAD_STATE_YIELDED) {
		DUK_DD(DUK_DDPRINT("resume state invalid: target thread must be INACTIVE or YIELDED"));
		goto state_error;
	}

	DUK_ASSERT(thr_resume->state == DUK_HTHREAD_STATE_INACTIVE ||
	           thr_resume->state == DUK_HTHREAD_STATE_YIELDED);

	/* Further state-dependent pre-checks */

	if (thr_resume->state == DUK_HTHREAD_STATE_YIELDED) {
		/* no pre-checks now, assume a previous yield() has left things in
		 * tip-top shape (longjmp handler will assert for these).
		 */
	} else {
		duk_hobject *h_fun;

		DUK_ASSERT(thr_resume->state == DUK_HTHREAD_STATE_INACTIVE);

		/* The initial function must be an ECMAScript function (but
		 * can be bound).  We must make sure of that before we longjmp
		 * because an error in the RESUME handler call processing will
		 * not be handled very cleanly.
		 */
		if ((thr_resume->callstack_top != 0) ||
		    (thr_resume->valstack_top - thr_resume->valstack != 1)) {
			goto state_error;
		}

		duk_push_tval(thr, DUK_GET_TVAL_NEGIDX(thr_resume, -1));
		duk_resolve_nonbound_function(thr);
		h_fun = duk_require_hobject(thr, -1);  /* reject lightfuncs on purpose */
		if (!DUK_HOBJECT_IS_CALLABLE(h_fun) || !DUK_HOBJECT_IS_COMPFUNC(h_fun)) {
			goto state_error;
		}
		duk_pop(thr);
	}

#if 0
	/* This check would prevent a heap destruction time finalizer from
	 * launching a coroutine, which would ensure that during finalization
	 * 'thr' would always equal heap_thread.  Normal runtime finalizers
	 * run with ms_running == 0, i.e. outside mark-and-sweep.  See GH-2030.
	 */
	if (thr->heap->ms_running) {
		DUK_D(DUK_DPRINT("refuse Duktape.Thread.resume() when ms_running != 0"));
		goto state_error;
	}
#endif

	/*
	 *  The error object has been augmented with a traceback and other
	 *  info from its creation point -- usually another thread.  The
	 *  error handler is called here right before throwing, but it also
	 *  runs in the resumer's thread.  It might be nice to get a traceback
	 *  from the resumee but this is not the case now.
	 */

#if defined(DUK_USE_AUGMENT_ERROR_THROW)
	if (is_error) {
		DUK_ASSERT_TOP(thr, 2);  /* value (error) is at stack top */
		duk_err_augment_error_throw(thr);  /* in resumer's context */
	}
#endif

#if defined(DUK_USE_DEBUG)
	if (is_error) {
		DUK_DDD(DUK_DDDPRINT("RESUME ERROR: thread=%!T, value=%!T",
		                     (duk_tval *) duk_get_tval(thr, 0),
		                     (duk_tval *) duk_get_tval(thr, 1)));
	} else if (thr_resume->state == DUK_HTHREAD_STATE_YIELDED) {
		DUK_DDD(DUK_DDDPRINT("RESUME NORMAL: thread=%!T, value=%!T",
		                     (duk_tval *) duk_get_tval(thr, 0),
		                     (duk_tval *) duk_get_tval(thr, 1)));
	} else {
		DUK_DDD(DUK_DDDPRINT("RESUME INITIAL: thread=%!T, value=%!T",
		                     (duk_tval *) duk_get_tval(thr, 0),
		                     (duk_tval *) duk_get_tval(thr, 1)));
	}
#endif

	thr->heap->lj.type = DUK_LJ_TYPE_RESUME;

	/* lj value2: thread */
	DUK_ASSERT(thr->valstack_bottom < thr->valstack_top);
	DUK_TVAL_SET_TVAL_UPDREF(thr, &thr->heap->lj.value2, &thr->valstack_bottom[0]);  /* side effects */

	/* lj value1: value */
	DUK_ASSERT(thr->valstack_bottom + 1 < thr->valstack_top);
	DUK_TVAL_SET_TVAL_UPDREF(thr, &thr->heap->lj.value1, &thr->valstack_bottom[1]);  /* side effects */
	DUK_TVAL_CHKFAST_INPLACE_SLOW(&thr->heap->lj.value1);

	thr->heap->lj.iserror = is_error;

	DUK_ASSERT(thr->heap->lj.jmpbuf_ptr != NULL);  /* call is from executor, so we know we have a jmpbuf */
	duk_err_longjmp(thr);  /* execution resumes in bytecode executor */
	DUK_UNREACHABLE();
	/* Never here, fall through to error (from compiler point of view). */

 state_error:
	DUK_DCERROR_TYPE_INVALID_STATE(thr);
}
#endif

/*
 *  Yield the current thread.
 *
 *  The thread must be in yieldable state: it must have a resumer, and there
 *  must not be any yield-preventing calls (native calls and constructor calls,
 *  currently) in the thread's call stack (otherwise a resume would not be
 *  possible later).  This method must be called from an ECMAScript function.
 *
 *  Args:
 *    - value
 *    - isError (defaults to false)
 *
 *  Note: yield and resume handling is currently asymmetric.
 */

#if defined(DUK_USE_COROUTINE_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_thread_yield(duk_hthread *thr) {
	duk_hobject *caller_func;
	duk_small_uint_t is_error;

	DUK_DDD(DUK_DDDPRINT("Duktape.Thread.yield(): value=%!T, is_error=%!T",
	                     (duk_tval *) duk_get_tval(thr, 0),
	                     (duk_tval *) duk_get_tval(thr, 1)));

	DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
	DUK_ASSERT(thr->heap->curr_thread == thr);

	DUK_ASSERT(duk_get_top(thr) == 2);
	is_error = (duk_small_uint_t) duk_to_boolean_top_pop(thr);
	DUK_ASSERT(duk_get_top(thr) == 1);

	/* [ value ] */

	/*
	 *  Thread state and calling context checks
	 */

	if (!thr->resumer) {
		DUK_DD(DUK_DDPRINT("yield state invalid: current thread must have a resumer"));
		goto state_error;
	}
	DUK_ASSERT(thr->resumer->state == DUK_HTHREAD_STATE_RESUMED);

	if (thr->callstack_top < 2) {
		DUK_DD(DUK_DDPRINT("yield state invalid: callstack should contain at least 2 entries (caller and Duktape.Thread.yield)"));
		goto state_error;
	}
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(thr->callstack_curr->parent != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);  /* us */
	DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr->parent) != NULL);  /* caller */

	caller_func = DUK_ACT_GET_FUNC(thr->callstack_curr->parent);
	if (!DUK_HOBJECT_IS_COMPFUNC(caller_func)) {
		DUK_DD(DUK_DDPRINT("yield state invalid: caller must be ECMAScript code"));
		goto state_error;
	}

	DUK_ASSERT(thr->callstack_preventcount >= 1);  /* should never be zero, because we (Duktape.Thread.yield) are on the stack */
	if (thr->callstack_preventcount != 1) {
		/* Note: the only yield-preventing call is Duktape.Thread.yield(), hence check for 1, not 0 */
		DUK_DD(DUK_DDPRINT("yield state invalid: there must be no yield-preventing calls in current thread callstack (preventcount is %ld)",
		                   (long) thr->callstack_preventcount));
		goto state_error;
	}

	/*
	 *  The error object has been augmented with a traceback and other
	 *  info from its creation point -- usually the current thread.
	 *  The error handler, however, is called right before throwing
	 *  and runs in the yielder's thread.
	 */

#if defined(DUK_USE_AUGMENT_ERROR_THROW)
	if (is_error) {
		DUK_ASSERT_TOP(thr, 1);  /* value (error) is at stack top */
		duk_err_augment_error_throw(thr);  /* in yielder's context */
	}
#endif

#if defined(DUK_USE_DEBUG)
	if (is_error) {
		DUK_DDD(DUK_DDDPRINT("YIELD ERROR: value=%!T",
		                     (duk_tval *) duk_get_tval(thr, 0)));
	} else {
		DUK_DDD(DUK_DDDPRINT("YIELD NORMAL: value=%!T",
		                     (duk_tval *) duk_get_tval(thr, 0)));
	}
#endif

	/*
	 *  Process yield
	 *
	 *  After longjmp(), processing continues in bytecode executor longjmp
	 *  handler, which will e.g. update thr->resumer to NULL.
	 */

	thr->heap->lj.type = DUK_LJ_TYPE_YIELD;

	/* lj value1: value */
	DUK_ASSERT(thr->valstack_bottom < thr->valstack_top);
	DUK_TVAL_SET_TVAL_UPDREF(thr, &thr->heap->lj.value1, &thr->valstack_bottom[0]);  /* side effects */
	DUK_TVAL_CHKFAST_INPLACE_SLOW(&thr->heap->lj.value1);

	thr->heap->lj.iserror = is_error;

	DUK_ASSERT(thr->heap->lj.jmpbuf_ptr != NULL);  /* call is from executor, so we know we have a jmpbuf */
	duk_err_longjmp(thr);  /* execution resumes in bytecode executor */
	DUK_UNREACHABLE();
	/* Never here, fall through to error (from compiler point of view). */

 state_error:
	DUK_DCERROR_TYPE_INVALID_STATE(thr);
}
#endif

#if defined(DUK_USE_COROUTINE_SUPPORT)
DUK_INTERNAL duk_ret_t duk_bi_thread_current(duk_hthread *thr) {
	duk_push_current_thread(thr);
	return 1;
}
#endif
/*
 *  Type error thrower, E5 Section 13.2.3.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL duk_ret_t duk_bi_type_error_thrower(duk_hthread *thr) {
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);
}
/*
 *  Fixed buffer helper useful for debugging, requires no allocation
 *  which is critical for debugging.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_DEBUG)

DUK_INTERNAL void duk_fb_put_bytes(duk_fixedbuffer *fb, const duk_uint8_t *buffer, duk_size_t length) {
	duk_size_t avail;
	duk_size_t copylen;

	avail = (fb->offset >= fb->length ? (duk_size_t) 0 : (duk_size_t) (fb->length - fb->offset));
	if (length > avail) {
		copylen = avail;
		fb->truncated = 1;
	} else {
		copylen = length;
	}
	duk_memcpy_unsafe(fb->buffer + fb->offset, buffer, copylen);
	fb->offset += copylen;
}

DUK_INTERNAL void duk_fb_put_byte(duk_fixedbuffer *fb, duk_uint8_t x) {
	duk_fb_put_bytes(fb, (const duk_uint8_t *) &x, 1);
}

DUK_INTERNAL void duk_fb_put_cstring(duk_fixedbuffer *fb, const char *x) {
	duk_fb_put_bytes(fb, (const duk_uint8_t *) x, (duk_size_t) DUK_STRLEN(x));
}

DUK_INTERNAL void duk_fb_sprintf(duk_fixedbuffer *fb, const char *fmt, ...) {
	duk_size_t avail;
	va_list ap;

	va_start(ap, fmt);
	avail = (fb->offset >= fb->length ? (duk_size_t) 0 : (duk_size_t) (fb->length - fb->offset));
	if (avail > 0) {
		duk_int_t res = (duk_int_t) DUK_VSNPRINTF((char *) (fb->buffer + fb->offset), avail, fmt, ap);
		if (res < 0) {
			/* error */
		} else if ((duk_size_t) res >= avail) {
			/* (maybe) truncated */
			fb->offset += avail;
			if ((duk_size_t) res > avail) {
				/* actual chars dropped (not just NUL term) */
				fb->truncated = 1;
			}
		} else {
			/* normal */
			fb->offset += (duk_size_t) res;
		}
	}
	va_end(ap);
}

DUK_INTERNAL void duk_fb_put_funcptr(duk_fixedbuffer *fb, duk_uint8_t *fptr, duk_size_t fptr_size) {
	char buf[64+1];
	duk_debug_format_funcptr(buf, sizeof(buf), fptr, fptr_size);
	buf[sizeof(buf) - 1] = (char) 0;
	duk_fb_put_cstring(fb, buf);
}

DUK_INTERNAL duk_bool_t duk_fb_is_full(duk_fixedbuffer *fb) {
	return (fb->offset >= fb->length);
}

#endif  /* DUK_USE_DEBUG */
/*
 *  Custom formatter for debug printing, allowing Duktape specific data
 *  structures (such as tagged values and heap objects) to be printed with
 *  a nice format string.  Because debug printing should not affect execution
 *  state, formatting here must be independent of execution (see implications
 *  below) and must not allocate memory.
 *
 *  Custom format tags begin with a '%!' to safely distinguish them from
 *  standard format tags.  The following conversions are supported:
 *
 *     %!T    tagged value (duk_tval *)
 *     %!O    heap object (duk_heaphdr *)
 *     %!I    decoded bytecode instruction
 *     %!X    bytecode instruction opcode name (arg is long)
 *     %!C    catcher (duk_catcher *)
 *     %!A    activation (duk_activation *)
 *
 *  Everything is serialized in a JSON-like manner.  The default depth is one
 *  level, internal prototype is not followed, and internal properties are not
 *  serialized.  The following modifiers change this behavior:
 *
 *     @      print pointers
 *     #      print binary representations (where applicable)
 *     d      deep traversal of own properties (not prototype)
 *     p      follow prototype chain (useless without 'd')
 *     i      include internal properties (other than prototype)
 *     x      hexdump buffers
 *     h      heavy formatting
 *
 *  For instance, the following serializes objects recursively, but does not
 *  follow the prototype chain nor print internal properties: "%!dO".
 *
 *  Notes:
 *
 *    * Standard snprintf return value semantics seem to vary.  This
 *      implementation returns the number of bytes it actually wrote
 *      (excluding the null terminator).  If retval == buffer size,
 *      output was truncated (except for corner cases).
 *
 *    * Output format is intentionally different from ECMAScript
 *      formatting requirements, as formatting here serves debugging
 *      of internals.
 *
 *    * Depth checking (and updating) is done in each type printer
 *      separately, to allow them to call each other freely.
 *
 *    * Some pathological structures might take ages to print (e.g.
 *      self recursion with 100 properties pointing to the object
 *      itself).  To guard against these, each printer also checks
 *      whether the output buffer is full; if so, early exit.
 *
 *    * Reference loops are detected using a loop stack.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_DEBUG)

/* #include stdio.h -> already included */
/* #include stdarg.h -> already included */
#include <string.h>

/* list of conversion specifiers that terminate a format tag;
 * this is unfortunately guesswork.
 */
#define DUK__ALLOWED_STANDARD_SPECIFIERS  "diouxXeEfFgGaAcsCSpnm"

/* maximum length of standard format tag that we support */
#define DUK__MAX_FORMAT_TAG_LENGTH  32

/* heapobj recursion depth when deep printing is selected */
#define DUK__DEEP_DEPTH_LIMIT  8

/* maximum recursion depth for loop detection stacks */
#define DUK__LOOP_STACK_DEPTH  256

/* must match bytecode defines now; build autogenerate? */
DUK_LOCAL const char * const duk__bc_optab[256] = {
	"LDREG", "STREG", "JUMP", "LDCONST", "LDINT", "LDINTX", "LDTHIS", "LDUNDEF",
	"LDNULL", "LDTRUE", "LDFALSE", "GETVAR", "BNOT", "LNOT", "UNM", "UNP",
	"EQ_RR", "EQ_CR", "EQ_RC", "EQ_CC", "NEQ_RR", "NEQ_CR", "NEQ_RC", "NEQ_CC",
	"SEQ_RR", "SEQ_CR", "SEQ_RC", "SEQ_CC", "SNEQ_RR", "SNEQ_CR", "SNEQ_RC", "SNEQ_CC",

	"GT_RR", "GT_CR", "GT_RC", "GT_CC", "GE_RR", "GE_CR", "GE_RC", "GE_CC",
	"LT_RR", "LT_CR", "LT_RC", "LT_CC", "LE_RR", "LE_CR", "LE_RC", "LE_CC",
	"IFTRUE_R", "IFTRUE_C", "IFFALSE_R", "IFFALSE_C", "ADD_RR", "ADD_CR", "ADD_RC", "ADD_CC",
	"SUB_RR", "SUB_CR", "SUB_RC", "SUB_CC", "MUL_RR", "MUL_CR", "MUL_RC", "MUL_CC",

	"DIV_RR", "DIV_CR", "DIV_RC", "DIV_CC", "MOD_RR", "MOD_CR", "MOD_RC", "MOD_CC",
	"EXP_RR", "EXP_CR", "EXP_RC", "EXP_CC", "BAND_RR", "BAND_CR", "BAND_RC", "BAND_CC",
	"BOR_RR", "BOR_CR", "BOR_RC", "BOR_CC", "BXOR_RR", "BXOR_CR", "BXOR_RC", "BXOR_CC",
	"BASL_RR", "BASL_CR", "BASL_RC", "BASL_CC", "BLSR_RR", "BLSR_CR", "BLSR_RC", "BLSR_CC",

	"BASR_RR", "BASR_CR", "BASR_RC", "BASR_CC", "INSTOF_RR", "INSTOF_CR", "INSTOF_RC", "INSTOF_CC",
	"IN_RR", "IN_CR", "IN_RC", "IN_CC", "GETPROP_RR", "GETPROP_CR", "GETPROP_RC", "GETPROP_CC",
	"PUTPROP_RR", "PUTPROP_CR", "PUTPROP_RC", "PUTPROP_CC", "DELPROP_RR", "DELPROP_CR", "DELPROP_RC", "DELPROP_CC",
	"PREINCR", "PREDECR", "POSTINCR", "POSTDECR", "PREINCV", "PREDECV", "POSTINCV", "POSTDECV",

	"PREINCP_RR", "PREINCP_CR", "PREINCP_RC", "PREINCP_CC", "PREDECP_RR", "PREDECP_CR", "PREDECP_RC", "PREDECP_CC",
	"POSTINCP_RR", "POSTINCP_CR", "POSTINCP_RC", "POSTINCP_CC", "POSTDECP_RR", "POSTDECP_CR", "POSTDECP_RC", "POSTDECP_CC",
	"DECLVAR_RR", "DECLVAR_CR", "DECLVAR_RC", "DECLVAR_CC", "REGEXP_RR", "REGEXP_RC", "REGEXP_CR", "REGEXP_CC",
	"CLOSURE", "TYPEOF", "TYPEOFID", "PUTVAR", "DELVAR", "RETREG", "RETUNDEF", "RETCONST",

	"RETCONSTN", "LABEL", "ENDLABEL", "BREAK", "CONTINUE", "TRYCATCH", "ENDTRY", "ENDCATCH",
	"ENDFIN", "THROW", "INVLHS", "CSREG", "CSVAR_RR", "CSVAR_CR", "CSVAR_RC", "CSVAR_CC",
	"CALL0", "CALL1", "CALL2", "CALL3", "CALL4", "CALL5", "CALL6", "CALL7",
	"CALL8", "CALL9", "CALL10", "CALL11", "CALL12", "CALL13", "CALL14", "CALL15",

	"NEWOBJ", "NEWARR", "MPUTOBJ", "MPUTOBJI", "INITSET", "INITGET", "MPUTARR", "MPUTARRI",
	"SETALEN", "INITENUM", "NEXTENUM", "NEWTARGET", "DEBUGGER", "NOP", "INVALID", "UNUSED207",
	"GETPROPC_RR", "GETPROPC_CR", "GETPROPC_RC", "GETPROPC_CC", "UNUSED212", "UNUSED213", "UNUSED214", "UNUSED215",
	"UNUSED216", "UNUSED217", "UNUSED218", "UNUSED219", "UNUSED220", "UNUSED221", "UNUSED222", "UNUSED223",

	"UNUSED224", "UNUSED225", "UNUSED226", "UNUSED227", "UNUSED228", "UNUSED229", "UNUSED230", "UNUSED231",
	"UNUSED232", "UNUSED233", "UNUSED234", "UNUSED235", "UNUSED236", "UNUSED237", "UNUSED238", "UNUSED239",
	"UNUSED240", "UNUSED241", "UNUSED242", "UNUSED243", "UNUSED244", "UNUSED245", "UNUSED246", "UNUSED247",
	"UNUSED248", "UNUSED249", "UNUSED250", "UNUSED251", "UNUSED252", "UNUSED253", "UNUSED254", "UNUSED255"
};

typedef struct duk__dprint_state duk__dprint_state;
struct duk__dprint_state {
	duk_fixedbuffer *fb;

	/* loop_stack_index could be perhaps be replaced by 'depth', but it's nice
	 * to not couple these two mechanisms unnecessarily.
	 */
	duk_hobject *loop_stack[DUK__LOOP_STACK_DEPTH];
	duk_int_t loop_stack_index;
	duk_int_t loop_stack_limit;

	duk_int_t depth;
	duk_int_t depth_limit;

	duk_bool_t pointer;
	duk_bool_t heavy;
	duk_bool_t binary;
	duk_bool_t follow_proto;
	duk_bool_t internal;
	duk_bool_t hexdump;
};

/* helpers */
DUK_LOCAL_DECL void duk__print_hstring(duk__dprint_state *st, duk_hstring *k, duk_bool_t quotes);
DUK_LOCAL_DECL void duk__print_hobject(duk__dprint_state *st, duk_hobject *h);
DUK_LOCAL_DECL void duk__print_hbuffer(duk__dprint_state *st, duk_hbuffer *h);
DUK_LOCAL_DECL void duk__print_tval(duk__dprint_state *st, duk_tval *tv);
DUK_LOCAL_DECL void duk__print_instr(duk__dprint_state *st, duk_instr_t ins);
DUK_LOCAL_DECL void duk__print_heaphdr(duk__dprint_state *st, duk_heaphdr *h);
DUK_LOCAL_DECL void duk__print_shared_heaphdr(duk__dprint_state *st, duk_heaphdr *h);
DUK_LOCAL_DECL void duk__print_shared_heaphdr_string(duk__dprint_state *st, duk_heaphdr_string *h);

DUK_LOCAL void duk__print_shared_heaphdr(duk__dprint_state *st, duk_heaphdr *h) {
	duk_fixedbuffer *fb = st->fb;

	if (st->heavy) {
		duk_fb_sprintf(fb, "(%p)", (void *) h);
	}

	if (!h) {
		return;
	}

	if (st->binary) {
		duk_size_t i;
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LBRACKET);
		for (i = 0; i < (duk_size_t) sizeof(*h); i++) {
			duk_fb_sprintf(fb, "%02lx", (unsigned long) ((duk_uint8_t *)h)[i]);
		}
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RBRACKET);
	}

#if defined(DUK_USE_REFERENCE_COUNTING)  /* currently implicitly also DUK_USE_DOUBLE_LINKED_HEAP */
	if (st->heavy) {
		duk_fb_sprintf(fb, "[h_next=%p,h_prev=%p,h_refcount=%lu,h_flags=%08lx,type=%ld,"
		               "reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
		               (void *) DUK_HEAPHDR_GET_NEXT(NULL, h),
		               (void *) DUK_HEAPHDR_GET_PREV(NULL, h),
		               (unsigned long) DUK_HEAPHDR_GET_REFCOUNT(h),
		               (unsigned long) DUK_HEAPHDR_GET_FLAGS(h),
		               (long) DUK_HEAPHDR_GET_TYPE(h),
		               (long) (DUK_HEAPHDR_HAS_REACHABLE(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_TEMPROOT(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZABLE(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZED(h) ? 1 : 0));
	}
#else
	if (st->heavy) {
		duk_fb_sprintf(fb, "[h_next=%p,h_flags=%08lx,type=%ld,reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
		               (void *) DUK_HEAPHDR_GET_NEXT(NULL, h),
		               (unsigned long) DUK_HEAPHDR_GET_FLAGS(h),
		               (long) DUK_HEAPHDR_GET_TYPE(h),
		               (long) (DUK_HEAPHDR_HAS_REACHABLE(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_TEMPROOT(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZABLE(h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZED(h) ? 1 : 0));
	}
#endif
}

DUK_LOCAL void duk__print_shared_heaphdr_string(duk__dprint_state *st, duk_heaphdr_string *h) {
	duk_fixedbuffer *fb = st->fb;

	if (st->heavy) {
		duk_fb_sprintf(fb, "(%p)", (void *) h);
	}

	if (!h) {
		return;
	}

	if (st->binary) {
		duk_size_t i;
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LBRACKET);
		for (i = 0; i < (duk_size_t) sizeof(*h); i++) {
			duk_fb_sprintf(fb, "%02lx", (unsigned long) ((duk_uint8_t *)h)[i]);
		}
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RBRACKET);
	}

#if defined(DUK_USE_REFERENCE_COUNTING)
	if (st->heavy) {
		duk_fb_sprintf(fb, "[h_refcount=%lu,h_flags=%08lx,type=%ld,reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
		               (unsigned long) DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h),
		               (unsigned long) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) h),
		               (long) DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h),
		               (long) (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_TEMPROOT((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZABLE((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) h) ? 1 : 0));
	}
#else
	if (st->heavy) {
		duk_fb_sprintf(fb, "[h_flags=%08lx,type=%ld,reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
		               (unsigned long) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) h),
		               (long) DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h),
		               (long) (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_TEMPROOT((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZABLE((duk_heaphdr *) h) ? 1 : 0),
		               (long) (DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) h) ? 1 : 0));
	}
#endif
}

DUK_LOCAL void duk__print_hstring(duk__dprint_state *st, duk_hstring *h, duk_bool_t quotes) {
	duk_fixedbuffer *fb = st->fb;
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;

	/* terminal type: no depth check */

	if (duk_fb_is_full(fb)) {
		return;
	}

	duk__print_shared_heaphdr_string(st, &h->hdr);

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	p = DUK_HSTRING_GET_DATA(h);
	p_end = p + DUK_HSTRING_GET_BYTELEN(h);

	if (p_end > p && p[0] == DUK_ASC_UNDERSCORE) {
		/* If property key begins with underscore, encode it with
		 * forced quotes (e.g. "_Foo") to distinguish it from encoded
		 * internal properties (e.g. \x82Bar -> _Bar).
		 */
		quotes = 1;
	}

	if (quotes) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_DOUBLEQUOTE);
	}
	while (p < p_end) {
		duk_uint8_t ch = *p++;

		/* two special escapes: '\' and '"', other printables as is */
		if (ch == '\\') {
			duk_fb_sprintf(fb, "\\\\");
		} else if (ch == '"') {
			duk_fb_sprintf(fb, "\\\"");
		} else if (ch >= 0x20 && ch <= 0x7e) {
			duk_fb_put_byte(fb, ch);
		} else if (ch == 0x82 && !quotes) {
			/* encode \x82Bar as _Bar if no quotes are
			 * applied, this is for readable internal keys.
			 */
			duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_UNDERSCORE);
		} else {
			duk_fb_sprintf(fb, "\\x%02lx", (unsigned long) ch);
		}
	}
	if (quotes) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_DOUBLEQUOTE);
	}
#if defined(DUK_USE_REFERENCE_COUNTING)
	/* XXX: limit to quoted strings only, to save keys from being cluttered? */
	duk_fb_sprintf(fb, "/%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT(&h->hdr));
#endif
}

#define DUK__COMMA()  do { \
		if (first) { \
			first = 0; \
		} else { \
			duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_COMMA); \
		} \
	} while (0)

DUK_LOCAL void duk__print_hobject(duk__dprint_state *st, duk_hobject *h) {
	duk_fixedbuffer *fb = st->fb;
	duk_uint_fast32_t i;
	duk_tval *tv;
	duk_hstring *key;
	duk_bool_t first = 1;
	const char *brace1 = "{";
	const char *brace2 = "}";
	duk_bool_t pushed_loopstack = 0;

	if (duk_fb_is_full(fb)) {
		return;
	}

	duk__print_shared_heaphdr(st, &h->hdr);

	if (h && DUK_HOBJECT_HAS_ARRAY_PART(h)) {
		brace1 = "[";
		brace2 = "]";
	}

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		goto finished;
	}

	if (st->depth >= st->depth_limit) {
		const char *subtype = "generic";

		if (DUK_HOBJECT_IS_COMPFUNC(h)) {
			subtype = "compfunc";
		} else if (DUK_HOBJECT_IS_NATFUNC(h)) {
			subtype = "natfunc";
		} else if (DUK_HOBJECT_IS_THREAD(h)) {
			subtype = "thread";
		} else if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			subtype = "bufobj";
		} else if (DUK_HOBJECT_IS_ARRAY(h)) {
			subtype = "array";
		}
		duk_fb_sprintf(fb, "%sobject/%s %p%s", (const char *) brace1, subtype, (void *) h, (const char *) brace2);
		return;
	}

	for (i = 0; i < (duk_uint_fast32_t) st->loop_stack_index; i++) {
		if (st->loop_stack[i] == h) {
			duk_fb_sprintf(fb, "%sLOOP:%p%s", (const char *) brace1, (void *) h, (const char *) brace2);
			return;
		}
	}

	/* after this, return paths should 'goto finished' for decrement */
	st->depth++;

	if (st->loop_stack_index >= st->loop_stack_limit) {
		duk_fb_sprintf(fb, "%sOUT-OF-LOOP-STACK%s", (const char *) brace1, (const char *) brace2);
		goto finished;
	}
	st->loop_stack[st->loop_stack_index++] = h;
	pushed_loopstack = 1;

	/*
	 *  Notation: double underscore used for internal properties which are not
	 *  stored in the property allocation (e.g. '__valstack').
	 */

	duk_fb_put_cstring(fb, brace1);

	if (DUK_HOBJECT_GET_PROPS(NULL, h)) {
		duk_uint32_t a_limit;

		a_limit = DUK_HOBJECT_GET_ASIZE(h);
		if (st->internal) {
			/* dump all allocated entries, unused entries print as 'unused',
			 * note that these may extend beyond current 'length' and look
			 * a bit funny.
			 */
		} else {
			/* leave out trailing 'unused' elements */
			while (a_limit > 0) {
				tv = DUK_HOBJECT_A_GET_VALUE_PTR(NULL, h, a_limit - 1);
				if (!DUK_TVAL_IS_UNUSED(tv)) {
					break;
				}
				a_limit--;
			}
		}

		for (i = 0; i < a_limit; i++) {
			tv = DUK_HOBJECT_A_GET_VALUE_PTR(NULL, h, i);
			DUK__COMMA();
			duk__print_tval(st, tv);
		}
		for (i = 0; i < DUK_HOBJECT_GET_ENEXT(h); i++) {
			key = DUK_HOBJECT_E_GET_KEY(NULL, h, i);
			if (!key) {
				continue;
			}
			if (!st->internal && DUK_HSTRING_HAS_HIDDEN(key)) {
				continue;
			}
			DUK__COMMA();
			duk__print_hstring(st, key, 0);
			duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_COLON);
			if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(NULL, h, i)) {
				duk_fb_sprintf(fb, "[get:%p,set:%p]",
				               (void *) DUK_HOBJECT_E_GET_VALUE(NULL, h, i).a.get,
				               (void *) DUK_HOBJECT_E_GET_VALUE(NULL, h, i).a.set);
			} else {
				tv = &DUK_HOBJECT_E_GET_VALUE(NULL, h, i).v;
				duk__print_tval(st, tv);
			}
			if (st->heavy) {
				duk_fb_sprintf(fb, "<%02lx>", (unsigned long) DUK_HOBJECT_E_GET_FLAGS(NULL, h, i));
			}
		}
	}
	if (st->internal) {
		if (DUK_HOBJECT_IS_ARRAY(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__array:true");
		}
		if (DUK_HOBJECT_HAS_EXTENSIBLE(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__extensible:true");
		}
		if (DUK_HOBJECT_HAS_CONSTRUCTABLE(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__constructable:true");
		}
		if (DUK_HOBJECT_HAS_BOUNDFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__boundfunc:true");
		}
		if (DUK_HOBJECT_HAS_COMPFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__compfunc:true");
		}
		if (DUK_HOBJECT_HAS_NATFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__natfunc:true");
		}
		if (DUK_HOBJECT_HAS_BUFOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__bufobj:true");
		}
		if (DUK_HOBJECT_IS_THREAD(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__thread:true");
		}
		if (DUK_HOBJECT_HAS_ARRAY_PART(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__array_part:true");
		}
		if (DUK_HOBJECT_HAS_STRICT(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__strict:true");
		}
		if (DUK_HOBJECT_HAS_NOTAIL(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__notail:true");
		}
		if (DUK_HOBJECT_HAS_NEWENV(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__newenv:true");
		}
		if (DUK_HOBJECT_HAS_NAMEBINDING(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__namebinding:true");
		}
		if (DUK_HOBJECT_HAS_CREATEARGS(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__createargs:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_array:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_stringobj:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_arguments:true");
		}
		if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_bufobj:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_proxyobj:true");
		}
	}

	if (st->internal && DUK_HOBJECT_IS_ARRAY(h)) {
		duk_harray *a = (duk_harray *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__length:%ld", (long) a->length);
		DUK__COMMA(); duk_fb_sprintf(fb, "__length_nonwritable:%ld", (long) a->length_nonwritable);
	} else if (st->internal && DUK_HOBJECT_IS_COMPFUNC(h)) {
		duk_hcompfunc *f = (duk_hcompfunc *) h;
		DUK__COMMA(); duk_fb_put_cstring(fb, "__data:");
		duk__print_hbuffer(st, (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(NULL, f));
		DUK__COMMA(); duk_fb_put_cstring(fb, "__lexenv:"); duk__print_hobject(st, DUK_HCOMPFUNC_GET_LEXENV(NULL, f));
		DUK__COMMA(); duk_fb_put_cstring(fb, "__varenv:"); duk__print_hobject(st, DUK_HCOMPFUNC_GET_VARENV(NULL, f));
		DUK__COMMA(); duk_fb_sprintf(fb, "__nregs:%ld", (long) f->nregs);
		DUK__COMMA(); duk_fb_sprintf(fb, "__nargs:%ld", (long) f->nargs);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
		DUK__COMMA(); duk_fb_sprintf(fb, "__start_line:%ld", (long) f->start_line);
		DUK__COMMA(); duk_fb_sprintf(fb, "__end_line:%ld", (long) f->end_line);
#endif
		DUK__COMMA(); duk_fb_put_cstring(fb, "__data:");
		duk__print_hbuffer(st, (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(NULL, f));
	} else if (st->internal && DUK_HOBJECT_IS_NATFUNC(h)) {
		duk_hnatfunc *f = (duk_hnatfunc *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__func:");
		duk_fb_put_funcptr(fb, (duk_uint8_t *) &f->func, sizeof(f->func));
		DUK__COMMA(); duk_fb_sprintf(fb, "__nargs:%ld", (long) f->nargs);
		DUK__COMMA(); duk_fb_sprintf(fb, "__magic:%ld", (long) f->magic);
	} else if (st->internal && DUK_HOBJECT_IS_DECENV(h)) {
		duk_hdecenv *e = (duk_hdecenv *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__thread:"); duk__print_hobject(st, (duk_hobject *) e->thread);
		DUK__COMMA(); duk_fb_sprintf(fb, "__varmap:"); duk__print_hobject(st, (duk_hobject *) e->varmap);
		DUK__COMMA(); duk_fb_sprintf(fb, "__regbase_byteoff:%ld", (long) e->regbase_byteoff);
	} else if (st->internal && DUK_HOBJECT_IS_OBJENV(h)) {
		duk_hobjenv *e = (duk_hobjenv *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__target:"); duk__print_hobject(st, (duk_hobject *) e->target);
		DUK__COMMA(); duk_fb_sprintf(fb, "__has_this:%ld", (long) e->has_this);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	} else if (st->internal && DUK_HOBJECT_IS_BUFOBJ(h)) {
		duk_hbufobj *b = (duk_hbufobj *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__buf:");
		duk__print_hbuffer(st, (duk_hbuffer *) b->buf);
		DUK__COMMA(); duk_fb_sprintf(fb, "__buf_prop:");
		duk__print_hobject(st, (duk_hobject *) b->buf_prop);
		DUK__COMMA(); duk_fb_sprintf(fb, "__offset:%ld", (long) b->offset);
		DUK__COMMA(); duk_fb_sprintf(fb, "__length:%ld", (long) b->length);
		DUK__COMMA(); duk_fb_sprintf(fb, "__shift:%ld", (long) b->shift);
		DUK__COMMA(); duk_fb_sprintf(fb, "__elemtype:%ld", (long) b->elem_type);
#endif
	} else if (st->internal && DUK_HOBJECT_IS_PROXY(h)) {
		duk_hproxy *p = (duk_hproxy *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__target:");
		duk__print_hobject(st, p->target);
		DUK__COMMA(); duk_fb_sprintf(fb, "__handler:");
		duk__print_hobject(st, p->handler);
	} else if (st->internal && DUK_HOBJECT_IS_THREAD(h)) {
		duk_hthread *t = (duk_hthread *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__ptr_curr_pc:%p", (void *) t->ptr_curr_pc);
		DUK__COMMA(); duk_fb_sprintf(fb, "__heap:%p", (void *) t->heap);
		DUK__COMMA(); duk_fb_sprintf(fb, "__strict:%ld", (long) t->strict);
		DUK__COMMA(); duk_fb_sprintf(fb, "__state:%ld", (long) t->state);
		DUK__COMMA(); duk_fb_sprintf(fb, "__unused1:%ld", (long) t->unused1);
		DUK__COMMA(); duk_fb_sprintf(fb, "__unused2:%ld", (long) t->unused2);
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack:%p", (void *) t->valstack);
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_end:%p/%ld", (void *) t->valstack_end, (long) (t->valstack_end - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_alloc_end:%p/%ld", (void *) t->valstack_alloc_end, (long) (t->valstack_alloc_end - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_bottom:%p/%ld", (void *) t->valstack_bottom, (long) (t->valstack_bottom - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_top:%p/%ld", (void *) t->valstack_top, (long) (t->valstack_top - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__callstack_curr:%p", (void *) t->callstack_curr);
		DUK__COMMA(); duk_fb_sprintf(fb, "__callstack_top:%ld", (long) t->callstack_top);
		DUK__COMMA(); duk_fb_sprintf(fb, "__callstack_preventcount:%ld", (long) t->callstack_preventcount);
		DUK__COMMA(); duk_fb_sprintf(fb, "__resumer:"); duk__print_hobject(st, (duk_hobject *) t->resumer);
		DUK__COMMA(); duk_fb_sprintf(fb, "__compile_ctx:%p", (void *) t->compile_ctx);
#if defined(DUK_USE_INTERRUPT_COUNTER)
		DUK__COMMA(); duk_fb_sprintf(fb, "__interrupt_counter:%ld", (long) t->interrupt_counter);
		DUK__COMMA(); duk_fb_sprintf(fb, "__interrupt_init:%ld", (long) t->interrupt_init);
#endif

		/* XXX: print built-ins array? */

	}
#if defined(DUK_USE_REFERENCE_COUNTING)
	if (st->internal) {
		DUK__COMMA(); duk_fb_sprintf(fb, "__refcount:%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h));
	}
#endif
	if (st->internal) {
		DUK__COMMA(); duk_fb_sprintf(fb, "__class:%ld", (long) DUK_HOBJECT_GET_CLASS_NUMBER(h));
	}

	DUK__COMMA(); duk_fb_sprintf(fb, "__heapptr:%p", (void *) h);  /* own pointer */

	/* prototype should be last, for readability */
	if (DUK_HOBJECT_GET_PROTOTYPE(NULL, h)) {
		if (st->follow_proto) {
			DUK__COMMA(); duk_fb_put_cstring(fb, "__prototype:"); duk__print_hobject(st, DUK_HOBJECT_GET_PROTOTYPE(NULL, h));
		} else {
			DUK__COMMA(); duk_fb_sprintf(fb, "__prototype:%p", (void *) DUK_HOBJECT_GET_PROTOTYPE(NULL, h));
		}
	}

	duk_fb_put_cstring(fb, brace2);

#if defined(DUK_USE_HOBJECT_HASH_PART)
	if (st->heavy && DUK_HOBJECT_GET_HSIZE(h) > 0) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LANGLE);
		for (i = 0; i < DUK_HOBJECT_GET_HSIZE(h); i++) {
			duk_uint_t h_idx = DUK_HOBJECT_H_GET_INDEX(NULL, h, i);
			if (i > 0) {
				duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_COMMA);
			}
			if (h_idx == DUK_HOBJECT_HASHIDX_UNUSED) {
				duk_fb_sprintf(fb, "u");
			} else if (h_idx == DUK_HOBJECT_HASHIDX_DELETED) {
				duk_fb_sprintf(fb, "d");
			} else {
				duk_fb_sprintf(fb, "%ld", (long) h_idx);
			}
		}
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RANGLE);
	}
#endif

 finished:
	st->depth--;
	if (pushed_loopstack) {
		st->loop_stack_index--;
		st->loop_stack[st->loop_stack_index] = NULL;
	}
}

DUK_LOCAL void duk__print_hbuffer(duk__dprint_state *st, duk_hbuffer *h) {
	duk_fixedbuffer *fb = st->fb;
	duk_size_t i, n;
	duk_uint8_t *p;

	if (duk_fb_is_full(fb)) {
		return;
	}

	/* terminal type: no depth check */

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	if (DUK_HBUFFER_HAS_DYNAMIC(h)) {
		if (DUK_HBUFFER_HAS_EXTERNAL(h)) {
			duk_hbuffer_external *g = (duk_hbuffer_external *) h;
			duk_fb_sprintf(fb, "buffer:external:%p:%ld",
			               (void *) DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(NULL, g),
			               (long) DUK_HBUFFER_EXTERNAL_GET_SIZE(g));
		} else {
			duk_hbuffer_dynamic *g = (duk_hbuffer_dynamic *) h;
			duk_fb_sprintf(fb, "buffer:dynamic:%p:%ld",
			               (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(NULL, g),
			               (long) DUK_HBUFFER_DYNAMIC_GET_SIZE(g));
		}
	} else {
		duk_fb_sprintf(fb, "buffer:fixed:%ld", (long) DUK_HBUFFER_GET_SIZE(h));
	}

#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_fb_sprintf(fb, "/%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT(&h->hdr));
#endif

	if (st->hexdump) {
		duk_fb_sprintf(fb, "=[");
		n = DUK_HBUFFER_GET_SIZE(h);
		p = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(NULL, h);
		for (i = 0; i < n; i++) {
			duk_fb_sprintf(fb, "%02lx", (unsigned long) p[i]);
		}
		duk_fb_sprintf(fb, "]");
	}
}

DUK_LOCAL void duk__print_heaphdr(duk__dprint_state *st, duk_heaphdr *h) {
	duk_fixedbuffer *fb = st->fb;

	if (duk_fb_is_full(fb)) {
		return;
	}

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	switch (DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING:
		duk__print_hstring(st, (duk_hstring *) h, 1);
		break;
	case DUK_HTYPE_OBJECT:
		duk__print_hobject(st, (duk_hobject *) h);
		break;
	case DUK_HTYPE_BUFFER:
		duk__print_hbuffer(st, (duk_hbuffer *) h);
		break;
	default:
		duk_fb_sprintf(fb, "[unknown htype %ld]", (long) DUK_HEAPHDR_GET_TYPE(h));
		break;
	}
}

DUK_LOCAL void duk__print_tval(duk__dprint_state *st, duk_tval *tv) {
	duk_fixedbuffer *fb = st->fb;

	if (duk_fb_is_full(fb)) {
		return;
	}

	/* depth check is done when printing an actual type */

	if (st->heavy) {
		duk_fb_sprintf(fb, "(%p)", (void *) tv);
	}

	if (!tv) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	if (st->binary) {
		duk_size_t i;
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LBRACKET);
		for (i = 0; i < (duk_size_t) sizeof(*tv); i++) {
			duk_fb_sprintf(fb, "%02lx", (unsigned long) ((duk_uint8_t *)tv)[i]);
		}
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RBRACKET);
	}

	if (st->heavy) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LANGLE);
	}
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED: {
		duk_fb_put_cstring(fb, "undefined");
		break;
	}
	case DUK_TAG_UNUSED: {
		duk_fb_put_cstring(fb, "unused");
		break;
	}
	case DUK_TAG_NULL: {
		duk_fb_put_cstring(fb, "null");
		break;
	}
	case DUK_TAG_BOOLEAN: {
		duk_fb_put_cstring(fb, DUK_TVAL_GET_BOOLEAN(tv) ? "true" : "false");
		break;
	}
	case DUK_TAG_STRING: {
		/* Note: string is a terminal heap object, so no depth check here */
		duk__print_hstring(st, DUK_TVAL_GET_STRING(tv), 1);
		break;
	}
	case DUK_TAG_OBJECT: {
		duk__print_hobject(st, DUK_TVAL_GET_OBJECT(tv));
		break;
	}
	case DUK_TAG_BUFFER: {
		duk__print_hbuffer(st, DUK_TVAL_GET_BUFFER(tv));
		break;
	}
	case DUK_TAG_POINTER: {
		duk_fb_sprintf(fb, "pointer:%p", (void *) DUK_TVAL_GET_POINTER(tv));
		break;
	}
	case DUK_TAG_LIGHTFUNC: {
		duk_c_function func;
		duk_small_uint_t lf_flags;

		DUK_TVAL_GET_LIGHTFUNC(tv, func, lf_flags);
		duk_fb_sprintf(fb, "lightfunc:");
		duk_fb_put_funcptr(fb, (duk_uint8_t *) &func, sizeof(func));
		duk_fb_sprintf(fb, ":%04lx", (long) lf_flags);
		break;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		duk_fb_sprintf(fb, "%.18g_F", (double) DUK_TVAL_GET_NUMBER(tv));
		break;
#endif
	default: {
		/* IEEE double is approximately 16 decimal digits; print a couple extra */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		duk_fb_sprintf(fb, "%.18g", (double) DUK_TVAL_GET_NUMBER(tv));
		break;
	}
	}
	if (st->heavy) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RANGLE);
	}
}

DUK_LOCAL void duk__print_instr(duk__dprint_state *st, duk_instr_t ins) {
	duk_fixedbuffer *fb = st->fb;
	duk_small_int_t op;
	const char *op_name;

	op = (duk_small_int_t) DUK_DEC_OP(ins);
	op_name = duk__bc_optab[op];

	/* XXX: option to fix opcode length so it lines up nicely */

	if (op == DUK_OP_JUMP) {
		duk_int_t diff1 = (duk_int_t) (DUK_DEC_ABC(ins) - DUK_BC_JUMP_BIAS);  /* from next pc */
		duk_int_t diff2 = diff1 + 1;                                          /* from curr pc */

		duk_fb_sprintf(fb, "%s %ld (to pc%c%ld)",
		               (const char *) op_name, (long) diff1,
		               (int) (diff2 >= 0 ? '+' : '-'),  /* char format: use int */
		               (long) (diff2 >= 0 ? diff2 : -diff2));
	} else {
		duk_fb_sprintf(fb, "%s %ld, %ld, %ld",
		               (const char *) op_name, (long) DUK_DEC_A(ins),
		               (long) DUK_DEC_B(ins), (long) DUK_DEC_C(ins));
	}
}

DUK_LOCAL void duk__print_opcode(duk__dprint_state *st, duk_small_int_t opcode) {
	duk_fixedbuffer *fb = st->fb;

	if (opcode < DUK_BC_OP_MIN || opcode > DUK_BC_OP_MAX) {
		duk_fb_sprintf(fb, "?(%ld)", (long) opcode);
	} else {
		duk_fb_sprintf(fb, "%s", (const char *) duk__bc_optab[opcode]);
	}
}

DUK_LOCAL void duk__print_catcher(duk__dprint_state *st, duk_catcher *cat) {
	duk_fixedbuffer *fb = st->fb;

	if (duk_fb_is_full(fb)) {
		return;
	}

	if (!cat) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	duk_fb_sprintf(fb, "[catcher ptr=%p parent=%p varname=%p pc_base=%p, idx_base=%ld, flags=0x%08lx]",
	               (void *) cat,
	               (void *) cat->parent, (void *) cat->h_varname, (void *) cat->pc_base,
		       (long) cat->idx_base, (unsigned long) cat->flags);
}


DUK_LOCAL void duk__print_activation(duk__dprint_state *st, duk_activation *act) {
	duk_fixedbuffer *fb = st->fb;

	if (duk_fb_is_full(fb)) {
		return;
	}

	if (!act) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	/* prev_caller: conditional, omitted on purpose, it's rarely used. */
	/* prev_line: conditional, omitted on purpose (but would be nice). */
	duk_fb_sprintf(fb, "[activation ptr=%p tv_func=<omit> func=%p parent=%p var_env=%p lex_env=%p cat=%p curr_pc=%p bottom_byteoff=%ld retval_byteoff=%ld reserve_byteoff=%ld flags=%ld]",
	               (void *) act,
	               (void *) act->func, (void *) act->parent, (void *) act->var_env,
		       (void *) act->lex_env, (void *) act->cat, (void *) act->curr_pc,
		       (long) act->bottom_byteoff, (long) act->retval_byteoff, (long) act->reserve_byteoff,
		       (long) act->flags);
}

DUK_INTERNAL duk_int_t duk_debug_vsnprintf(char *str, duk_size_t size, const char *format, va_list ap) {
	duk_fixedbuffer fb;
	const char *p = format;
	const char *p_end = p + DUK_STRLEN(format);
	duk_int_t retval;

	duk_memzero(&fb, sizeof(fb));
	fb.buffer = (duk_uint8_t *) str;
	fb.length = size;
	fb.offset = 0;
	fb.truncated = 0;

	while (p < p_end) {
		char ch = *p++;
		const char *p_begfmt = NULL;
		duk_bool_t got_exclamation = 0;
		duk_bool_t got_long = 0;  /* %lf, %ld etc */
		duk__dprint_state st;

		if (ch != DUK_ASC_PERCENT) {
			duk_fb_put_byte(&fb, (duk_uint8_t) ch);
			continue;
		}

		/*
		 *  Format tag parsing.  Since we don't understand all the
		 *  possible format tags allowed, we just scan for a terminating
		 *  specifier and keep track of relevant modifiers that we do
		 *  understand.  See man 3 printf.
		 */

		duk_memzero(&st, sizeof(st));
		st.fb = &fb;
		st.depth = 0;
		st.depth_limit = 1;
		st.loop_stack_index = 0;
		st.loop_stack_limit = DUK__LOOP_STACK_DEPTH;

		p_begfmt = p - 1;
		while (p < p_end) {
			ch = *p++;

			if (ch == DUK_ASC_STAR) {
				/* unsupported: would consume multiple args */
				goto format_error;
			} else if (ch == DUK_ASC_PERCENT) {
				duk_fb_put_byte(&fb, (duk_uint8_t) DUK_ASC_PERCENT);
				break;
			} else if (ch == DUK_ASC_EXCLAMATION) {
				got_exclamation = 1;
			} else if (!got_exclamation && ch == DUK_ASC_LC_L) {
				got_long = 1;
			} else if (got_exclamation && ch == DUK_ASC_LC_D) {
				st.depth_limit = DUK__DEEP_DEPTH_LIMIT;
			} else if (got_exclamation && ch == DUK_ASC_LC_P) {
				st.follow_proto = 1;
			} else if (got_exclamation && ch == DUK_ASC_LC_I) {
				st.internal = 1;
			} else if (got_exclamation && ch == DUK_ASC_LC_X) {
				st.hexdump = 1;
			} else if (got_exclamation && ch == DUK_ASC_LC_H) {
				st.heavy = 1;
			} else if (got_exclamation && ch == DUK_ASC_ATSIGN) {
				st.pointer = 1;
			} else if (got_exclamation && ch == DUK_ASC_HASH) {
				st.binary = 1;
			} else if (got_exclamation && ch == DUK_ASC_UC_T) {
				duk_tval *t = va_arg(ap, duk_tval *);
				if (st.pointer && !st.heavy) {
					duk_fb_sprintf(&fb, "(%p)", (void *) t);
				}
				duk__print_tval(&st, t);
				break;
			} else if (got_exclamation && ch == DUK_ASC_UC_O) {
				duk_heaphdr *t = va_arg(ap, duk_heaphdr *);
				if (st.pointer && !st.heavy) {
					duk_fb_sprintf(&fb, "(%p)", (void *) t);
				}
				duk__print_heaphdr(&st, t);
				break;
			} else if (got_exclamation && ch == DUK_ASC_UC_I) {
				duk_instr_t t = va_arg(ap, duk_instr_t);
				duk__print_instr(&st, t);
				break;
			} else if (got_exclamation && ch == DUK_ASC_UC_X) {
				long t = va_arg(ap, long);
				duk__print_opcode(&st, (duk_small_int_t) t);
				break;
			} else if (got_exclamation && ch == DUK_ASC_UC_C) {
				duk_catcher *t = va_arg(ap, duk_catcher *);
				duk__print_catcher(&st, t);
				break;
			} else if (got_exclamation && ch == DUK_ASC_UC_A) {
				duk_activation *t = va_arg(ap, duk_activation *);
				duk__print_activation(&st, t);
				break;
			} else if (!got_exclamation && strchr(DUK__ALLOWED_STANDARD_SPECIFIERS, (int) ch)) {
				char fmtbuf[DUK__MAX_FORMAT_TAG_LENGTH];
				duk_size_t fmtlen;

				DUK_ASSERT(p >= p_begfmt);
				fmtlen = (duk_size_t) (p - p_begfmt);
				if (fmtlen >= sizeof(fmtbuf)) {
					/* format is too large, abort */
					goto format_error;
				}
				duk_memzero(fmtbuf, sizeof(fmtbuf));
				duk_memcpy(fmtbuf, p_begfmt, fmtlen);

				/* assume exactly 1 arg, which is why '*' is forbidden; arg size still
				 * depends on type though.
				 */

				if (ch == DUK_ASC_LC_F || ch == DUK_ASC_LC_G || ch == DUK_ASC_LC_E) {
					/* %f and %lf both consume a 'long' */
					double arg = va_arg(ap, double);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_D && got_long) {
					/* %ld */
					long arg = va_arg(ap, long);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_D) {
					/* %d; only 16 bits are guaranteed */
					int arg = va_arg(ap, int);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_U && got_long) {
					/* %lu */
					unsigned long arg = va_arg(ap, unsigned long);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_U) {
					/* %u; only 16 bits are guaranteed */
					unsigned int arg = va_arg(ap, unsigned int);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_X && got_long) {
					/* %lx */
					unsigned long arg = va_arg(ap, unsigned long);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_X) {
					/* %x; only 16 bits are guaranteed */
					unsigned int arg = va_arg(ap, unsigned int);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else if (ch == DUK_ASC_LC_S) {
					/* %s */
					const char *arg = va_arg(ap, const char *);
					if (arg == NULL) {
						/* '%s' and NULL is not portable, so special case
						 * it for debug printing.
						 */
						duk_fb_sprintf(&fb, "NULL");
					} else {
						duk_fb_sprintf(&fb, fmtbuf, arg);
					}
				} else if (ch == DUK_ASC_LC_P) {
					/* %p */
					void *arg = va_arg(ap, void *);
					if (arg == NULL) {
						/* '%p' and NULL is portable, but special case it
						 * anyway to get a standard NULL marker in logs.
						 */
						duk_fb_sprintf(&fb, "NULL");
					} else {
						duk_fb_sprintf(&fb, fmtbuf, arg);
					}
				} else if (ch == DUK_ASC_LC_C) {
					/* '%c', passed concretely as int */
					int arg = va_arg(ap, int);
					duk_fb_sprintf(&fb, fmtbuf, arg);
				} else {
					/* Should not happen. */
					duk_fb_sprintf(&fb, "INVALID-FORMAT(%s)", (const char *) fmtbuf);
				}
				break;
			} else {
				/* ignore */
			}
		}
	}
	goto done;

 format_error:
	duk_fb_put_cstring(&fb, "FMTERR");
	/* fall through */

 done:
	retval = (duk_int_t) fb.offset;
	duk_fb_put_byte(&fb, (duk_uint8_t) 0);

	/* return total chars written excluding terminator */
	return retval;
}

#if 0  /*unused*/
DUK_INTERNAL duk_int_t duk_debug_snprintf(char *str, duk_size_t size, const char *format, ...) {
	duk_int_t retval;
	va_list ap;
	va_start(ap, format);
	retval = duk_debug_vsnprintf(str, size, format, ap);
	va_end(ap);
	return retval;
}
#endif

/* Formatting function pointers is tricky: there is no standard pointer for
 * function pointers and the size of a function pointer may depend on the
 * specific pointer type.  This helper formats a function pointer based on
 * its memory layout to get something useful on most platforms.
 */
DUK_INTERNAL void duk_debug_format_funcptr(char *buf, duk_size_t buf_size, duk_uint8_t *fptr, duk_size_t fptr_size) {
	duk_size_t i;
	duk_uint8_t *p = (duk_uint8_t *) buf;
	duk_uint8_t *p_end = (duk_uint8_t *) (buf + buf_size - 1);

	DUK_ASSERT(buf != NULL);
	duk_memzero(buf, buf_size);

	for (i = 0; i < fptr_size; i++) {
		duk_int_t left = (duk_int_t) (p_end - p);
		duk_uint8_t ch;
		if (left <= 0) {
			break;
		}

		/* Quite approximate but should be useful for little and big endian. */
#if defined(DUK_USE_INTEGER_BE)
		ch = fptr[i];
#else
		ch = fptr[fptr_size - 1 - i];
#endif
		p += DUK_SNPRINTF((char *) p, (duk_size_t) left, "%02lx", (unsigned long) ch);
	}
}

#endif  /* DUK_USE_DEBUG */

/* automatic undefs */
#undef DUK__ALLOWED_STANDARD_SPECIFIERS
#undef DUK__COMMA
#undef DUK__DEEP_DEPTH_LIMIT
#undef DUK__LOOP_STACK_DEPTH
#undef DUK__MAX_FORMAT_TAG_LENGTH
/*
 *  Duktape debugger
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_DEBUGGER_SUPPORT)

/*
 *  Assert helpers
 */

#if defined(DUK_USE_ASSERTIONS)
#define DUK__DBG_TPORT_ENTER() do { \
		DUK_ASSERT(heap->dbg_calling_transport == 0); \
		heap->dbg_calling_transport = 1; \
	} while (0)
#define DUK__DBG_TPORT_EXIT() do { \
		DUK_ASSERT(heap->dbg_calling_transport == 1); \
		heap->dbg_calling_transport = 0; \
	} while (0)
#else
#define DUK__DBG_TPORT_ENTER() do {} while (0)
#define DUK__DBG_TPORT_EXIT() do {} while (0)
#endif

/*
 *  Helper structs
 */

typedef union {
	void *p;
	duk_uint_t b[1];
	/* Use b[] to access the size of the union, which is strictly not
	 * correct.  Can't use fixed size unless there's feature detection
	 * for pointer byte size.
	 */
} duk__ptr_union;

/*
 *  Detach handling
 */

#define DUK__SET_CONN_BROKEN(thr,reason) do { \
		/* For now shared handler is fine. */ \
		duk__debug_do_detach1((thr)->heap, (reason)); \
	} while (0)

DUK_LOCAL void duk__debug_do_detach1(duk_heap *heap, duk_int_t reason) {
	/* Can be called multiple times with no harm.  Mark the transport
	 * bad (dbg_read_cb == NULL) and clear state except for the detached
	 * callback and the udata field.  The detached callback is delayed
	 * to the message loop so that it can be called between messages;
	 * this avoids corner cases related to immediate debugger reattach
	 * inside the detached callback.
	 */

	if (heap->dbg_detaching) {
		DUK_D(DUK_DPRINT("debugger already detaching, ignore detach1"));
		return;
	}

	DUK_D(DUK_DPRINT("debugger transport detaching, marking transport broken"));

	heap->dbg_detaching = 1;  /* prevent multiple in-progress detaches */

	if (heap->dbg_write_cb != NULL) {
		duk_hthread *thr;

		thr = heap->heap_thread;
		DUK_ASSERT(thr != NULL);

		duk_debug_write_notify(thr, DUK_DBG_CMD_DETACHING);
		duk_debug_write_int(thr, reason);
		duk_debug_write_eom(thr);
	}

	heap->dbg_read_cb = NULL;
	heap->dbg_write_cb = NULL;
	heap->dbg_peek_cb = NULL;
	heap->dbg_read_flush_cb = NULL;
	heap->dbg_write_flush_cb = NULL;
	heap->dbg_request_cb = NULL;
	/* heap->dbg_detached_cb: keep */
	/* heap->dbg_udata: keep */
	/* heap->dbg_processing: keep on purpose to avoid debugger re-entry in detaching state */
	heap->dbg_state_dirty = 0;
	heap->dbg_force_restart = 0;
	heap->dbg_pause_flags = 0;
	heap->dbg_pause_act = NULL;
	heap->dbg_pause_startline = 0;
	heap->dbg_have_next_byte = 0;
	duk_debug_clear_paused(heap);  /* XXX: some overlap with field inits above */
	heap->dbg_state_dirty = 0;     /* XXX: clear_paused sets dirty; rework? */

	/* Ensure there are no stale active breakpoint pointers.
	 * Breakpoint list is currently kept - we could empty it
	 * here but we'd need to handle refcounts correctly, and
	 * we'd need a 'thr' reference for that.
	 *
	 * XXX: clear breakpoint on either attach or detach?
	 */
	heap->dbg_breakpoints_active[0] = (duk_breakpoint *) NULL;
}

DUK_LOCAL void duk__debug_do_detach2(duk_heap *heap) {
	duk_debug_detached_function detached_cb;
	void *detached_udata;
	duk_hthread *thr;

	thr = heap->heap_thread;
	if (thr == NULL) {
		DUK_ASSERT(heap->dbg_detached_cb == NULL);
		return;
	}

	/* Safe to call multiple times. */

	detached_cb = heap->dbg_detached_cb;
	detached_udata = heap->dbg_udata;
	heap->dbg_detached_cb = NULL;
	heap->dbg_udata = NULL;

	if (detached_cb) {
		/* Careful here: state must be wiped before the call
		 * so that we can cleanly handle a re-attach from
		 * inside the callback.
		 */
		DUK_D(DUK_DPRINT("detached during message loop, delayed call to detached_cb"));
		detached_cb(thr, detached_udata);
	}

	heap->dbg_detaching = 0;
}

DUK_INTERNAL void duk_debug_do_detach(duk_heap *heap) {
	duk__debug_do_detach1(heap, 0);
	duk__debug_do_detach2(heap);
}

/* Called on a read/write error: NULL all callbacks except the detached
 * callback so that we never accidentally call them after a read/write
 * error has been indicated.  This is especially important for the transport
 * I/O callbacks to fulfill guaranteed callback semantics.
 */
DUK_LOCAL void duk__debug_null_most_callbacks(duk_hthread *thr) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);

	heap = thr->heap;
	DUK_D(DUK_DPRINT("transport read/write error, NULL all callbacks expected detached"));
	heap->dbg_read_cb = NULL;
	heap->dbg_write_cb = NULL;  /* this is especially critical to avoid another write call in detach1() */
	heap->dbg_peek_cb = NULL;
	heap->dbg_read_flush_cb = NULL;
	heap->dbg_write_flush_cb = NULL;
	heap->dbg_request_cb = NULL;
	/* keep heap->dbg_detached_cb */
}

/*
 *  Pause handling
 */

DUK_LOCAL void duk__debug_set_pause_state(duk_hthread *thr, duk_heap *heap, duk_small_uint_t pause_flags) {
	duk_uint_fast32_t line;

	line = duk_debug_curr_line(thr);
	if (line == 0) {
		/* No line info for current function. */
		duk_small_uint_t updated_flags;

		updated_flags = pause_flags & ~(DUK_PAUSE_FLAG_LINE_CHANGE);
		DUK_D(DUK_DPRINT("no line info for current activation, disable line-based pause flags: 0x%08lx -> 0x%08lx",
		                 (long) pause_flags, (long) updated_flags));
		pause_flags = updated_flags;
	}

	heap->dbg_pause_flags = pause_flags;
	heap->dbg_pause_act = thr->callstack_curr;
	heap->dbg_pause_startline = (duk_uint32_t) line;
	heap->dbg_state_dirty = 1;

	DUK_D(DUK_DPRINT("set state for automatic pause triggers, flags=0x%08lx, act=%p, startline=%ld",
	                 (long) heap->dbg_pause_flags, (void *) heap->dbg_pause_act,
	                 (long) heap->dbg_pause_startline));
}

/*
 *  Debug connection peek and flush primitives
 */

DUK_INTERNAL duk_bool_t duk_debug_read_peek(duk_hthread *thr) {
	duk_heap *heap;
	duk_bool_t ret;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	if (heap->dbg_read_cb == NULL) {
		DUK_D(DUK_DPRINT("attempt to peek in detached state, return zero (= no data)"));
		return 0;
	}
	if (heap->dbg_peek_cb == NULL) {
		DUK_DD(DUK_DDPRINT("no peek callback, return zero (= no data)"));
		return 0;
	}

	DUK__DBG_TPORT_ENTER();
	ret = (duk_bool_t) (heap->dbg_peek_cb(heap->dbg_udata) > 0);
	DUK__DBG_TPORT_EXIT();
	return ret;
}

DUK_INTERNAL void duk_debug_read_flush(duk_hthread *thr) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	if (heap->dbg_read_cb == NULL) {
		DUK_D(DUK_DPRINT("attempt to read flush in detached state, ignore"));
		return;
	}
	if (heap->dbg_read_flush_cb == NULL) {
		DUK_DD(DUK_DDPRINT("no read flush callback, ignore"));
		return;
	}

	DUK__DBG_TPORT_ENTER();
	heap->dbg_read_flush_cb(heap->dbg_udata);
	DUK__DBG_TPORT_EXIT();
}

DUK_INTERNAL void duk_debug_write_flush(duk_hthread *thr) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	if (heap->dbg_read_cb == NULL) {
		DUK_D(DUK_DPRINT("attempt to write flush in detached state, ignore"));
		return;
	}
	if (heap->dbg_write_flush_cb == NULL) {
		DUK_DD(DUK_DDPRINT("no write flush callback, ignore"));
		return;
	}

	DUK__DBG_TPORT_ENTER();
	heap->dbg_write_flush_cb(heap->dbg_udata);
	DUK__DBG_TPORT_EXIT();
}

/*
 *  Debug connection skip primitives
 */

/* Skip fully. */
DUK_INTERNAL void duk_debug_skip_bytes(duk_hthread *thr, duk_size_t length) {
	duk_uint8_t dummy[64];
	duk_size_t now;

	DUK_ASSERT(thr != NULL);

	while (length > 0) {
		now = (length > sizeof(dummy) ? sizeof(dummy) : length);
		duk_debug_read_bytes(thr, dummy, now);
		length -= now;
	}
}

DUK_INTERNAL void duk_debug_skip_byte(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);

	(void) duk_debug_read_byte(thr);
}

/*
 *  Debug connection read primitives
 */

/* Peek ahead in the stream one byte. */
DUK_INTERNAL uint8_t duk_debug_peek_byte(duk_hthread *thr) {
	/* It is important not to call this if the last byte read was an EOM.
	 * Reading ahead in this scenario would cause unnecessary blocking if
	 * another message is not available.
	 */

	duk_uint8_t x;

	x = duk_debug_read_byte(thr);
	thr->heap->dbg_have_next_byte = 1;
	thr->heap->dbg_next_byte = x;
	return x;
}

/* Read fully. */
DUK_INTERNAL void duk_debug_read_bytes(duk_hthread *thr, duk_uint8_t *data, duk_size_t length) {
	duk_heap *heap;
	duk_uint8_t *p;
	duk_size_t left;
	duk_size_t got;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(data != NULL);

	if (heap->dbg_read_cb == NULL) {
		DUK_D(DUK_DPRINT("attempt to read %ld bytes in detached state, return zero data", (long) length));
		goto fail;
	}

	/* NOTE: length may be zero */
	p = data;
	if (length >= 1 && heap->dbg_have_next_byte) {
		heap->dbg_have_next_byte = 0;
		*p++ = heap->dbg_next_byte;
	}
	for (;;) {
		left = (duk_size_t) ((data + length) - p);
		if (left == 0) {
			break;
		}
		DUK_ASSERT(heap->dbg_read_cb != NULL);
		DUK_ASSERT(left >= 1);
#if defined(DUK_USE_DEBUGGER_TRANSPORT_TORTURE)
		left = 1;
#endif
		DUK__DBG_TPORT_ENTER();
		got = heap->dbg_read_cb(heap->dbg_udata, (char *) p, left);
		DUK__DBG_TPORT_EXIT();

		if (got == 0 || got > left) {
			DUK_D(DUK_DPRINT("connection error during read, return zero data"));
			duk__debug_null_most_callbacks(thr);  /* avoid calling write callback in detach1() */
			DUK__SET_CONN_BROKEN(thr, 1);
			goto fail;
		}
		p += got;
	}
	return;

 fail:
	duk_memzero((void *) data, (size_t) length);
}

DUK_INTERNAL duk_uint8_t duk_debug_read_byte(duk_hthread *thr) {
	duk_uint8_t x;

	x = 0;  /* just in case callback is broken and won't write 'x' */
	duk_debug_read_bytes(thr, &x, 1);
	return x;
}

DUK_LOCAL duk_uint32_t duk__debug_read_uint32_raw(duk_hthread *thr) {
	duk_uint8_t buf[4];

	DUK_ASSERT(thr != NULL);

	duk_debug_read_bytes(thr, buf, 4);
	return ((duk_uint32_t) buf[0] << 24) |
	       ((duk_uint32_t) buf[1] << 16) |
	       ((duk_uint32_t) buf[2] << 8) |
	       (duk_uint32_t) buf[3];
}

DUK_LOCAL duk_int32_t duk__debug_read_int32_raw(duk_hthread *thr) {
	return (duk_int32_t) duk__debug_read_uint32_raw(thr);
}

DUK_LOCAL duk_uint16_t duk__debug_read_uint16_raw(duk_hthread *thr) {
	duk_uint8_t buf[2];

	DUK_ASSERT(thr != NULL);

	duk_debug_read_bytes(thr, buf, 2);
	return ((duk_uint16_t) buf[0] << 8) |
	       (duk_uint16_t) buf[1];
}

DUK_INTERNAL duk_int32_t duk_debug_read_int(duk_hthread *thr) {
	duk_small_uint_t x;
	duk_small_uint_t t;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);
	if (x >= 0xc0) {
		t = duk_debug_read_byte(thr);
		return (duk_int32_t) (((x - 0xc0) << 8) + t);
	} else if (x >= 0x80) {
		return (duk_int32_t) (x - 0x80);
	} else if (x == DUK_DBG_IB_INT4) {
		return (duk_int32_t) duk__debug_read_uint32_raw(thr);
	}

	DUK_D(DUK_DPRINT("debug connection error: failed to decode int"));
	DUK__SET_CONN_BROKEN(thr, 1);
	return 0;
}

DUK_LOCAL duk_hstring *duk__debug_read_hstring_raw(duk_hthread *thr, duk_uint32_t len) {
	duk_uint8_t buf[31];
	duk_uint8_t *p;

	if (len <= sizeof(buf)) {
		duk_debug_read_bytes(thr, buf, (duk_size_t) len);
		duk_push_lstring(thr, (const char *) buf, (duk_size_t) len);
	} else {
		p = (duk_uint8_t *) duk_push_fixed_buffer(thr, (duk_size_t) len);  /* zero for paranoia */
		DUK_ASSERT(p != NULL);
		duk_debug_read_bytes(thr, p, (duk_size_t) len);
		(void) duk_buffer_to_string(thr, -1);  /* Safety relies on debug client, which is OK. */
	}

	return duk_require_hstring(thr, -1);
}

DUK_INTERNAL duk_hstring *duk_debug_read_hstring(duk_hthread *thr) {
	duk_small_uint_t x;
	duk_uint32_t len;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);
	if (x >= 0x60 && x <= 0x7f) {
		/* For short strings, use a fixed temp buffer. */
		len = (duk_uint32_t) (x - 0x60);
	} else if (x == DUK_DBG_IB_STR2) {
		len = (duk_uint32_t) duk__debug_read_uint16_raw(thr);
	} else if (x == DUK_DBG_IB_STR4) {
		len = (duk_uint32_t) duk__debug_read_uint32_raw(thr);
	} else {
		goto fail;
	}

	return duk__debug_read_hstring_raw(thr, len);

 fail:
	DUK_D(DUK_DPRINT("debug connection error: failed to decode int"));
	DUK__SET_CONN_BROKEN(thr, 1);
	duk_push_hstring_empty(thr);  /* always push some string */
	return duk_require_hstring(thr, -1);
}

DUK_LOCAL duk_hbuffer *duk__debug_read_hbuffer_raw(duk_hthread *thr, duk_uint32_t len) {
	duk_uint8_t *p;

	p = (duk_uint8_t *) duk_push_fixed_buffer(thr, (duk_size_t) len);  /* zero for paranoia */
	DUK_ASSERT(p != NULL);
	duk_debug_read_bytes(thr, p, (duk_size_t) len);

	return duk_require_hbuffer(thr, -1);
}

DUK_LOCAL void *duk__debug_read_pointer_raw(duk_hthread *thr) {
	duk_small_uint_t x;
	duk__ptr_union pu;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);
	if (x != sizeof(pu)) {
		goto fail;
	}
	duk_debug_read_bytes(thr, (duk_uint8_t *) &pu.p, sizeof(pu));
#if defined(DUK_USE_INTEGER_LE)
	duk_byteswap_bytes((duk_uint8_t *) pu.b, sizeof(pu));
#endif
	return (void *) pu.p;

 fail:
	DUK_D(DUK_DPRINT("debug connection error: failed to decode pointer"));
	DUK__SET_CONN_BROKEN(thr, 1);
	return (void *) NULL;
}

DUK_LOCAL duk_double_t duk__debug_read_double_raw(duk_hthread *thr) {
	duk_double_union du;

	DUK_ASSERT(sizeof(du.uc) == 8);
	duk_debug_read_bytes(thr, (duk_uint8_t *) du.uc, sizeof(du.uc));
	DUK_DBLUNION_DOUBLE_NTOH(&du);
	return du.d;
}

#if 0
DUK_INTERNAL duk_heaphdr *duk_debug_read_heapptr(duk_hthread *thr) {
	duk_small_uint_t x;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);
	if (x != DUK_DBG_IB_HEAPPTR) {
		goto fail;
	}

	return (duk_heaphdr *) duk__debug_read_pointer_raw(thr);

 fail:
	DUK_D(DUK_DPRINT("debug connection error: failed to decode heapptr"));
	DUK__SET_CONN_BROKEN(thr, 1);
	return NULL;
}
#endif

DUK_INTERNAL duk_heaphdr *duk_debug_read_any_ptr(duk_hthread *thr) {
	duk_small_uint_t x;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);
	switch (x) {
	case DUK_DBG_IB_OBJECT:
	case DUK_DBG_IB_POINTER:
	case DUK_DBG_IB_HEAPPTR:
		/* Accept any pointer-like value; for 'object' dvalue, read
		 * and ignore the class number.
		 */
		if (x == DUK_DBG_IB_OBJECT) {
			duk_debug_skip_byte(thr);
		}
		break;
	default:
		goto fail;
	}

	return (duk_heaphdr *) duk__debug_read_pointer_raw(thr);

 fail:
	DUK_D(DUK_DPRINT("debug connection error: failed to decode any pointer (object, pointer, heapptr)"));
	DUK__SET_CONN_BROKEN(thr, 1);
	return NULL;
}

DUK_INTERNAL duk_tval *duk_debug_read_tval(duk_hthread *thr) {
	duk_uint8_t x;
	duk_uint_t t;
	duk_uint32_t len;

	DUK_ASSERT(thr != NULL);

	x = duk_debug_read_byte(thr);

	if (x >= 0xc0) {
		t = (duk_uint_t) (x - 0xc0);
		t = (t << 8) + duk_debug_read_byte(thr);
		duk_push_uint(thr, (duk_uint_t) t);
		goto return_ptr;
	}
	if (x >= 0x80) {
		duk_push_uint(thr, (duk_uint_t) (x - 0x80));
		goto return_ptr;
	}
	if (x >= 0x60) {
		len = (duk_uint32_t) (x - 0x60);
		duk__debug_read_hstring_raw(thr, len);
		goto return_ptr;
	}

	switch (x) {
	case DUK_DBG_IB_INT4: {
		duk_int32_t i = duk__debug_read_int32_raw(thr);
		duk_push_i32(thr, i);
		break;
	}
	case DUK_DBG_IB_STR4: {
		len = duk__debug_read_uint32_raw(thr);
		duk__debug_read_hstring_raw(thr, len);
		break;
	}
	case DUK_DBG_IB_STR2: {
		len = duk__debug_read_uint16_raw(thr);
		duk__debug_read_hstring_raw(thr, len);
		break;
	}
	case DUK_DBG_IB_BUF4: {
		len = duk__debug_read_uint32_raw(thr);
		duk__debug_read_hbuffer_raw(thr, len);
		break;
	}
	case DUK_DBG_IB_BUF2: {
		len = duk__debug_read_uint16_raw(thr);
		duk__debug_read_hbuffer_raw(thr, len);
		break;
	}
	case DUK_DBG_IB_UNDEFINED: {
		duk_push_undefined(thr);
		break;
	}
	case DUK_DBG_IB_NULL: {
		duk_push_null(thr);
		break;
	}
	case DUK_DBG_IB_TRUE: {
		duk_push_true(thr);
		break;
	}
	case DUK_DBG_IB_FALSE: {
		duk_push_false(thr);
		break;
	}
	case DUK_DBG_IB_NUMBER: {
		duk_double_t d;
		d = duk__debug_read_double_raw(thr);
		duk_push_number(thr, d);
		break;
	}
	case DUK_DBG_IB_OBJECT: {
		duk_heaphdr *h;
		duk_debug_skip_byte(thr);
		h = (duk_heaphdr *) duk__debug_read_pointer_raw(thr);
		duk_push_heapptr(thr, (void *) h);
		break;
	}
	case DUK_DBG_IB_POINTER: {
		void *ptr;
		ptr = duk__debug_read_pointer_raw(thr);
		duk_push_pointer(thr, ptr);
		break;
	}
	case DUK_DBG_IB_LIGHTFUNC: {
		/* XXX: Not needed for now, so not implemented.  Note that
		 * function pointers may have different size/layout than
		 * a void pointer.
		 */
		DUK_D(DUK_DPRINT("reading lightfunc values unimplemented"));
		goto fail;
	}
	case DUK_DBG_IB_HEAPPTR: {
		duk_heaphdr *h;
		h = (duk_heaphdr *) duk__debug_read_pointer_raw(thr);
		duk_push_heapptr(thr, (void *) h);
		break;
	}
	case DUK_DBG_IB_UNUSED:  /* unused: not accepted in inbound messages */
	default:
		goto fail;
	}

 return_ptr:
	return DUK_GET_TVAL_NEGIDX(thr, -1);

 fail:
	DUK_D(DUK_DPRINT("debug connection error: failed to decode tval"));
	DUK__SET_CONN_BROKEN(thr, 1);
	return NULL;
}

/*
 *  Debug connection write primitives
 */

/* Write fully. */
DUK_INTERNAL void duk_debug_write_bytes(duk_hthread *thr, const duk_uint8_t *data, duk_size_t length) {
	duk_heap *heap;
	const duk_uint8_t *p;
	duk_size_t left;
	duk_size_t got;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(length == 0 || data != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	if (heap->dbg_write_cb == NULL) {
		DUK_D(DUK_DPRINT("attempt to write %ld bytes in detached state, ignore", (long) length));
		return;
	}
	if (length == 0) {
		/* Avoid doing an actual write callback with length == 0,
		 * because that's reserved for a write flush.
		 */
		return;
	}
	DUK_ASSERT(data != NULL);

	p = data;
	for (;;) {
		left = (duk_size_t) ((data + length) - p);
		if (left == 0) {
			break;
		}
		DUK_ASSERT(heap->dbg_write_cb != NULL);
		DUK_ASSERT(left >= 1);
#if defined(DUK_USE_DEBUGGER_TRANSPORT_TORTURE)
		left = 1;
#endif
		DUK__DBG_TPORT_ENTER();
		got = heap->dbg_write_cb(heap->dbg_udata, (const char *) p, left);
		DUK__DBG_TPORT_EXIT();

		if (got == 0 || got > left) {
			duk__debug_null_most_callbacks(thr);  /* avoid calling write callback in detach1() */
			DUK_D(DUK_DPRINT("connection error during write"));
			DUK__SET_CONN_BROKEN(thr, 1);
			return;
		}
		p += got;
	}
}

DUK_INTERNAL void duk_debug_write_byte(duk_hthread *thr, duk_uint8_t x) {
	duk_debug_write_bytes(thr, (const duk_uint8_t *) &x, 1);
}

DUK_INTERNAL void duk_debug_write_unused(duk_hthread *thr) {
	duk_debug_write_byte(thr, DUK_DBG_IB_UNUSED);
}

DUK_INTERNAL void duk_debug_write_undefined(duk_hthread *thr) {
	duk_debug_write_byte(thr, DUK_DBG_IB_UNDEFINED);
}

#if defined(DUK_USE_DEBUGGER_INSPECT)
DUK_INTERNAL void duk_debug_write_null(duk_hthread *thr) {
	duk_debug_write_byte(thr, DUK_DBG_IB_NULL);
}
#endif

DUK_INTERNAL void duk_debug_write_boolean(duk_hthread *thr, duk_uint_t val) {
	duk_debug_write_byte(thr, val ? DUK_DBG_IB_TRUE : DUK_DBG_IB_FALSE);
}

/* Write signed 32-bit integer. */
DUK_INTERNAL void duk_debug_write_int(duk_hthread *thr, duk_int32_t x) {
	duk_uint8_t buf[5];
	duk_size_t len;

	DUK_ASSERT(thr != NULL);

	if (x >= 0 && x <= 0x3fL) {
		buf[0] = (duk_uint8_t) (0x80 + x);
		len = 1;
	} else if (x >= 0 && x <= 0x3fffL) {
		buf[0] = (duk_uint8_t) (0xc0 + (x >> 8));
		buf[1] = (duk_uint8_t) (x & 0xff);
		len = 2;
	} else {
		/* Signed integers always map to 4 bytes now. */
		buf[0] = (duk_uint8_t) DUK_DBG_IB_INT4;
		buf[1] = (duk_uint8_t) ((x >> 24) & 0xff);
		buf[2] = (duk_uint8_t) ((x >> 16) & 0xff);
		buf[3] = (duk_uint8_t) ((x >> 8) & 0xff);
		buf[4] = (duk_uint8_t) (x & 0xff);
		len = 5;
	}
	duk_debug_write_bytes(thr, buf, len);
}

/* Write unsigned 32-bit integer. */
DUK_INTERNAL void duk_debug_write_uint(duk_hthread *thr, duk_uint32_t x) {
	/* The debugger protocol doesn't support a plain integer encoding for
	 * the full 32-bit unsigned range (only 32-bit signed).  For now,
	 * unsigned 32-bit values simply written as signed ones.  This is not
	 * a concrete issue except for 32-bit heaphdr fields.  Proper solutions
	 * would be to (a) write such integers as IEEE doubles or (b) add an
	 * unsigned 32-bit dvalue.
	 */
	if (x >= 0x80000000UL) {
		DUK_D(DUK_DPRINT("writing unsigned integer 0x%08lx as signed integer",
		                 (long) x));
	}
	duk_debug_write_int(thr, (duk_int32_t) x);
}

DUK_INTERNAL void duk_debug_write_strbuf(duk_hthread *thr, const char *data, duk_size_t length, duk_uint8_t marker_base) {
	duk_uint8_t buf[5];
	duk_size_t buflen;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(length == 0 || data != NULL);

	if (length <= 0x1fUL && marker_base == DUK_DBG_IB_STR4) {
		/* For strings, special form for short lengths. */
		buf[0] = (duk_uint8_t) (0x60 + length);
		buflen = 1;
	} else if (length <= 0xffffUL) {
		buf[0] = (duk_uint8_t) (marker_base + 1);
		buf[1] = (duk_uint8_t) (length >> 8);
		buf[2] = (duk_uint8_t) (length & 0xff);
		buflen = 3;
	} else {
		buf[0] = (duk_uint8_t) marker_base;
		buf[1] = (duk_uint8_t) (length >> 24);
		buf[2] = (duk_uint8_t) ((length >> 16) & 0xff);
		buf[3] = (duk_uint8_t) ((length >> 8) & 0xff);
		buf[4] = (duk_uint8_t) (length & 0xff);
		buflen = 5;
	}

	duk_debug_write_bytes(thr, (const duk_uint8_t *) buf, buflen);
	duk_debug_write_bytes(thr, (const duk_uint8_t *) data, length);
}

DUK_INTERNAL void duk_debug_write_string(duk_hthread *thr, const char *data, duk_size_t length) {
	duk_debug_write_strbuf(thr, data, length, DUK_DBG_IB_STR4);
}

DUK_INTERNAL void duk_debug_write_cstring(duk_hthread *thr, const char *data) {
	DUK_ASSERT(thr != NULL);

	duk_debug_write_string(thr,
	                       data,
	                       data ? DUK_STRLEN(data) : 0);
}

DUK_INTERNAL void duk_debug_write_hstring(duk_hthread *thr, duk_hstring *h) {
	DUK_ASSERT(thr != NULL);

	/* XXX: differentiate null pointer from empty string? */
	duk_debug_write_string(thr,
	                       (h != NULL ? (const char *) DUK_HSTRING_GET_DATA(h) : NULL),
	                       (h != NULL ? (duk_size_t) DUK_HSTRING_GET_BYTELEN(h) : 0));
}

DUK_LOCAL void duk__debug_write_hstring_safe_top(duk_hthread *thr) {
	duk_debug_write_hstring(thr, duk_safe_to_hstring(thr, -1));
}

DUK_INTERNAL void duk_debug_write_buffer(duk_hthread *thr, const char *data, duk_size_t length) {
	duk_debug_write_strbuf(thr, data, length, DUK_DBG_IB_BUF4);
}

DUK_INTERNAL void duk_debug_write_hbuffer(duk_hthread *thr, duk_hbuffer *h) {
	DUK_ASSERT(thr != NULL);

	duk_debug_write_buffer(thr,
	                       (h != NULL ? (const char *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h) : NULL),
	                       (h != NULL ? (duk_size_t) DUK_HBUFFER_GET_SIZE(h) : 0));
}

DUK_LOCAL void duk__debug_write_pointer_raw(duk_hthread *thr, void *ptr, duk_uint8_t ibyte) {
	duk_uint8_t buf[2];
	duk__ptr_union pu;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(sizeof(ptr) >= 1 && sizeof(ptr) <= 16);
	/* ptr may be NULL */

	buf[0] = ibyte;
	buf[1] = sizeof(pu);
	duk_debug_write_bytes(thr, buf, 2);
	pu.p = (void *) ptr;
#if defined(DUK_USE_INTEGER_LE)
	duk_byteswap_bytes((duk_uint8_t *) pu.b, sizeof(pu));
#endif
	duk_debug_write_bytes(thr, (const duk_uint8_t *) &pu.p, (duk_size_t) sizeof(pu));
}

DUK_INTERNAL void duk_debug_write_pointer(duk_hthread *thr, void *ptr) {
	duk__debug_write_pointer_raw(thr, ptr, DUK_DBG_IB_POINTER);
}

#if defined(DUK_USE_DEBUGGER_DUMPHEAP) || defined(DUK_USE_DEBUGGER_INSPECT)
DUK_INTERNAL void duk_debug_write_heapptr(duk_hthread *thr, duk_heaphdr *h) {
	duk__debug_write_pointer_raw(thr, (void *) h, DUK_DBG_IB_HEAPPTR);
}
#endif  /* DUK_USE_DEBUGGER_DUMPHEAP || DUK_USE_DEBUGGER_INSPECT */

DUK_INTERNAL void duk_debug_write_hobject(duk_hthread *thr, duk_hobject *obj) {
	duk_uint8_t buf[3];
	duk__ptr_union pu;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(sizeof(obj) >= 1 && sizeof(obj) <= 16);
	DUK_ASSERT(obj != NULL);

	buf[0] = DUK_DBG_IB_OBJECT;
	buf[1] = (duk_uint8_t) DUK_HOBJECT_GET_CLASS_NUMBER(obj);
	buf[2] = sizeof(pu);
	duk_debug_write_bytes(thr, buf, 3);
	pu.p = (void *) obj;
#if defined(DUK_USE_INTEGER_LE)
	duk_byteswap_bytes((duk_uint8_t *) pu.b, sizeof(pu));
#endif
	duk_debug_write_bytes(thr, (const duk_uint8_t *) &pu.p, (duk_size_t) sizeof(pu));
}

DUK_INTERNAL void duk_debug_write_tval(duk_hthread *thr, duk_tval *tv) {
	duk_c_function lf_func;
	duk_small_uint_t lf_flags;
	duk_uint8_t buf[4];
	duk_double_union du1;
	duk_double_union du2;
	duk_int32_t i32;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED:
		duk_debug_write_byte(thr, DUK_DBG_IB_UNDEFINED);
		break;
	case DUK_TAG_UNUSED:
		duk_debug_write_byte(thr, DUK_DBG_IB_UNUSED);
		break;
	case DUK_TAG_NULL:
		duk_debug_write_byte(thr, DUK_DBG_IB_NULL);
		break;
	case DUK_TAG_BOOLEAN:
		DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv) == 0 ||
		           DUK_TVAL_GET_BOOLEAN(tv) == 1);
		duk_debug_write_boolean(thr, DUK_TVAL_GET_BOOLEAN(tv));
		break;
	case DUK_TAG_POINTER:
		duk_debug_write_pointer(thr, (void *) DUK_TVAL_GET_POINTER(tv));
		break;
	case DUK_TAG_LIGHTFUNC:
		DUK_TVAL_GET_LIGHTFUNC(tv, lf_func, lf_flags);
		buf[0] = DUK_DBG_IB_LIGHTFUNC;
		buf[1] = (duk_uint8_t) (lf_flags >> 8);
		buf[2] = (duk_uint8_t) (lf_flags & 0xff);
		buf[3] = sizeof(lf_func);
		duk_debug_write_bytes(thr, buf, 4);
		duk_debug_write_bytes(thr, (const duk_uint8_t *) &lf_func, sizeof(lf_func));
		break;
	case DUK_TAG_STRING:
		duk_debug_write_hstring(thr, DUK_TVAL_GET_STRING(tv));
		break;
	case DUK_TAG_OBJECT:
		duk_debug_write_hobject(thr, DUK_TVAL_GET_OBJECT(tv));
		break;
	case DUK_TAG_BUFFER:
		duk_debug_write_hbuffer(thr, DUK_TVAL_GET_BUFFER(tv));
		break;
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default:
		/* Numbers are normalized to big (network) endian.  We can
		 * (but are not required) to use integer dvalues when there's
		 * no loss of precision.
		 *
		 * XXX: share check with other code; this check is slow but
		 * reliable and doesn't require careful exponent/mantissa
		 * mask tricks as in the fastint downgrade code.
		 */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		du1.d = DUK_TVAL_GET_NUMBER(tv);
		i32 = (duk_int32_t) du1.d;
		du2.d = (duk_double_t) i32;

		DUK_DD(DUK_DDPRINT("i32=%ld du1=%02x%02x%02x%02x%02x%02x%02x%02x "
		                   "du2=%02x%02x%02x%02x%02x%02x%02x%02x",
		                   (long) i32,
		                   (unsigned int) du1.uc[0], (unsigned int) du1.uc[1],
		                   (unsigned int) du1.uc[2], (unsigned int) du1.uc[3],
		                   (unsigned int) du1.uc[4], (unsigned int) du1.uc[5],
		                   (unsigned int) du1.uc[6], (unsigned int) du1.uc[7],
		                   (unsigned int) du2.uc[0], (unsigned int) du2.uc[1],
		                   (unsigned int) du2.uc[2], (unsigned int) du2.uc[3],
		                   (unsigned int) du2.uc[4], (unsigned int) du2.uc[5],
		                   (unsigned int) du2.uc[6], (unsigned int) du2.uc[7]));

		if (duk_memcmp((const void *) du1.uc, (const void *) du2.uc, sizeof(du1.uc)) == 0) {
			duk_debug_write_int(thr, i32);
		} else {
			DUK_DBLUNION_DOUBLE_HTON(&du1);
			duk_debug_write_byte(thr, DUK_DBG_IB_NUMBER);
			duk_debug_write_bytes(thr, (const duk_uint8_t *) du1.uc, sizeof(du1.uc));
		}
	}
}

#if defined(DUK_USE_DEBUGGER_DUMPHEAP)
/* Variant for writing duk_tvals so that any heap allocated values are
 * written out as tagged heap pointers.
 */
DUK_LOCAL void duk__debug_write_tval_heapptr(duk_hthread *thr, duk_tval *tv) {
	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		duk_debug_write_heapptr(thr, h);
	} else {
		duk_debug_write_tval(thr, tv);
	}
}
#endif  /* DUK_USE_DEBUGGER_DUMPHEAP */

/*
 *  Debug connection message write helpers
 */

#if 0  /* unused */
DUK_INTERNAL void duk_debug_write_request(duk_hthread *thr, duk_small_uint_t command) {
	duk_debug_write_byte(thr, DUK_DBG_IB_REQUEST);
	duk_debug_write_int(thr, command);
}
#endif

DUK_INTERNAL void duk_debug_write_reply(duk_hthread *thr) {
	duk_debug_write_byte(thr, DUK_DBG_IB_REPLY);
}

DUK_INTERNAL void duk_debug_write_error_eom(duk_hthread *thr, duk_small_uint_t err_code, const char *msg) {
	/* Allow NULL 'msg' */
	duk_debug_write_byte(thr, DUK_DBG_IB_ERROR);
	duk_debug_write_int(thr, (duk_int32_t) err_code);
	duk_debug_write_cstring(thr, msg);
	duk_debug_write_eom(thr);
}

DUK_INTERNAL void duk_debug_write_notify(duk_hthread *thr, duk_small_uint_t command) {
	duk_debug_write_byte(thr, DUK_DBG_IB_NOTIFY);
	duk_debug_write_int(thr, (duk_int32_t) command);
}

DUK_INTERNAL void duk_debug_write_eom(duk_hthread *thr) {
	duk_debug_write_byte(thr, DUK_DBG_IB_EOM);

	/* As an initial implementation, write flush after every EOM (and the
	 * version identifier).  A better implementation would flush only when
	 * Duktape is finished processing messages so that a flush only happens
	 * after all outbound messages are finished on that occasion.
	 */
	duk_debug_write_flush(thr);
}

/*
 *  Status message and helpers
 */

DUK_INTERNAL duk_uint_fast32_t duk_debug_curr_line(duk_hthread *thr) {
	duk_activation *act;
	duk_uint_fast32_t line;
	duk_uint_fast32_t pc;

	act = thr->callstack_curr;
	if (act == NULL) {
		return 0;
	}

	/* We're conceptually between two opcodes; act->pc indicates the next
	 * instruction to be executed.  This is usually the correct pc/line to
	 * indicate in Status.  (For the 'debugger' statement this now reports
	 * the pc/line after the debugger statement because the debugger opcode
	 * has already been executed.)
	 */

	pc = duk_hthread_get_act_curr_pc(thr, act);

	/* XXX: this should be optimized to be a raw query and avoid valstack
	 * operations if possible.
	 */
	duk_push_tval(thr, &act->tv_func);
	line = duk_hobject_pc2line_query(thr, -1, pc);
	duk_pop(thr);
	return line;
}

DUK_INTERNAL void duk_debug_send_status(duk_hthread *thr) {
	duk_activation *act;

	duk_debug_write_notify(thr, DUK_DBG_CMD_STATUS);
	duk_debug_write_int(thr, (DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap) ? 1 : 0));

	act = thr->callstack_curr;
	if (act == NULL) {
		duk_debug_write_undefined(thr);
		duk_debug_write_undefined(thr);
		duk_debug_write_int(thr, 0);
		duk_debug_write_int(thr, 0);
	} else {
		duk_push_tval(thr, &act->tv_func);
		duk_get_prop_literal(thr, -1, "fileName");
		duk__debug_write_hstring_safe_top(thr);
		duk_get_prop_literal(thr, -2, "name");
		duk__debug_write_hstring_safe_top(thr);
		duk_pop_3(thr);
		/* Report next pc/line to be executed. */
		duk_debug_write_uint(thr, (duk_uint32_t) duk_debug_curr_line(thr));
		duk_debug_write_uint(thr, (duk_uint32_t) duk_hthread_get_act_curr_pc(thr, act));
	}

	duk_debug_write_eom(thr);
}

#if defined(DUK_USE_DEBUGGER_THROW_NOTIFY)
DUK_INTERNAL void duk_debug_send_throw(duk_hthread *thr, duk_bool_t fatal) {
	/*
	 *  NFY <int: 5> <int: fatal> <str: msg> <str: filename> <int: linenumber> EOM
	 */

	duk_activation *act;
	duk_uint32_t pc;

	DUK_ASSERT(thr->valstack_top > thr->valstack);  /* At least: ... [err] */

	duk_debug_write_notify(thr, DUK_DBG_CMD_THROW);
	duk_debug_write_int(thr, (duk_int32_t) fatal);

	/* Report thrown value to client coerced to string */
	duk_dup_top(thr);
	duk__debug_write_hstring_safe_top(thr);
	duk_pop(thr);

	if (duk_is_error(thr, -1)) {
		/* Error instance, use augmented error data directly */
		duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_FILE_NAME);
		duk__debug_write_hstring_safe_top(thr);
		duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_LINE_NUMBER);
		duk_debug_write_uint(thr, duk_get_uint(thr, -1));
		duk_pop_2(thr);
	} else {
		/* For anything other than an Error instance, we calculate the
		 * error location directly from the current activation if one
		 * exists.
		 */
		act = thr->callstack_curr;
		if (act != NULL) {
			duk_push_tval(thr, &act->tv_func);
			duk_get_prop_literal(thr, -1, "fileName");
			duk__debug_write_hstring_safe_top(thr);
			pc = (duk_uint32_t) duk_hthread_get_act_prev_pc(thr, act);
			duk_debug_write_uint(thr, (duk_uint32_t) duk_hobject_pc2line_query(thr, -2, pc));
			duk_pop_2(thr);
		} else {
			/* Can happen if duk_throw() is called on an empty
			 * callstack.
			 */
			duk_debug_write_cstring(thr, "");
			duk_debug_write_uint(thr, 0);
		}
	}

	duk_debug_write_eom(thr);
}
#endif  /* DUK_USE_DEBUGGER_THROW_NOTIFY */

/*
 *  Debug message processing
 */

/* Skip dvalue. */
DUK_LOCAL duk_bool_t duk__debug_skip_dvalue(duk_hthread *thr) {
	duk_uint8_t x;
	duk_uint32_t len;

	x = duk_debug_read_byte(thr);

	if (x >= 0xc0) {
		duk_debug_skip_byte(thr);
		return 0;
	}
	if (x >= 0x80) {
		return 0;
	}
	if (x >= 0x60) {
		duk_debug_skip_bytes(thr, (duk_size_t) (x - 0x60));
		return 0;
	}
	switch(x) {
	case DUK_DBG_IB_EOM:
		return 1;  /* Return 1: got EOM */
	case DUK_DBG_IB_REQUEST:
	case DUK_DBG_IB_REPLY:
	case DUK_DBG_IB_ERROR:
	case DUK_DBG_IB_NOTIFY:
		break;
	case DUK_DBG_IB_INT4:
		(void) duk__debug_read_uint32_raw(thr);
		break;
	case DUK_DBG_IB_STR4:
	case DUK_DBG_IB_BUF4:
		len = duk__debug_read_uint32_raw(thr);
		duk_debug_skip_bytes(thr, len);
		break;
	case DUK_DBG_IB_STR2:
	case DUK_DBG_IB_BUF2:
		len = duk__debug_read_uint16_raw(thr);
		duk_debug_skip_bytes(thr, len);
		break;
	case DUK_DBG_IB_UNUSED:
	case DUK_DBG_IB_UNDEFINED:
	case DUK_DBG_IB_NULL:
	case DUK_DBG_IB_TRUE:
	case DUK_DBG_IB_FALSE:
		break;
	case DUK_DBG_IB_NUMBER:
		duk_debug_skip_bytes(thr, 8);
		break;
	case DUK_DBG_IB_OBJECT:
		duk_debug_skip_byte(thr);
		len = duk_debug_read_byte(thr);
		duk_debug_skip_bytes(thr, len);
		break;
	case DUK_DBG_IB_POINTER:
	case DUK_DBG_IB_HEAPPTR:
		len = duk_debug_read_byte(thr);
		duk_debug_skip_bytes(thr, len);
		break;
	case DUK_DBG_IB_LIGHTFUNC:
		duk_debug_skip_bytes(thr, 2);
		len = duk_debug_read_byte(thr);
		duk_debug_skip_bytes(thr, len);
		break;
	default:
		goto fail;
	}

	return 0;

 fail:
	DUK__SET_CONN_BROKEN(thr, 1);
	return 1;  /* Pretend like we got EOM */
}

/* Skip dvalues to EOM. */
DUK_LOCAL void duk__debug_skip_to_eom(duk_hthread *thr) {
	for (;;) {
		if (duk__debug_skip_dvalue(thr)) {
			break;
		}
	}
}

/* Read and validate a call stack index.  If index is invalid, write out an
 * error message and return zero.
 */
DUK_LOCAL duk_int32_t duk__debug_read_validate_csindex(duk_hthread *thr) {
	duk_int32_t level;
	level = duk_debug_read_int(thr);
	if (level >= 0 || -level > (duk_int32_t) thr->callstack_top) {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_NOTFOUND, "invalid callstack index");
		return 0;  /* zero indicates failure */
	}
	return level;
}

/* Read a call stack index and lookup the corresponding duk_activation.
 * If index is invalid, write out an error message and return NULL.
 */
DUK_LOCAL duk_activation *duk__debug_read_level_get_activation(duk_hthread *thr) {
	duk_activation *act;
	duk_int32_t level;

	level = duk_debug_read_int(thr);
	act = duk_hthread_get_activation_for_level(thr, level);
	if (act == NULL) {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_NOTFOUND, "invalid callstack index");
	}
	return act;
}

/*
 *  Simple commands
 */

DUK_LOCAL void duk__debug_handle_basic_info(duk_hthread *thr, duk_heap *heap) {
	DUK_UNREF(heap);
	DUK_D(DUK_DPRINT("debug command Version"));

	duk_debug_write_reply(thr);
	duk_debug_write_int(thr, DUK_VERSION);
	duk_debug_write_cstring(thr, DUK_GIT_DESCRIBE);
	duk_debug_write_cstring(thr, DUK_USE_TARGET_INFO);
#if defined(DUK_USE_DOUBLE_LE)
	duk_debug_write_int(thr, 1);
#elif defined(DUK_USE_DOUBLE_ME)
	duk_debug_write_int(thr, 2);
#elif defined(DUK_USE_DOUBLE_BE)
	duk_debug_write_int(thr, 3);
#else
	duk_debug_write_int(thr, 0);
#endif
	duk_debug_write_int(thr, (duk_int_t) sizeof(void *));
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_trigger_status(duk_hthread *thr, duk_heap *heap) {
	DUK_UNREF(heap);
	DUK_D(DUK_DPRINT("debug command TriggerStatus"));

	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);
	heap->dbg_state_dirty = 1;
}

DUK_LOCAL void duk__debug_handle_pause(duk_hthread *thr, duk_heap *heap) {
	DUK_D(DUK_DPRINT("debug command Pause"));
	duk_debug_set_paused(heap);
	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_resume(duk_hthread *thr, duk_heap *heap) {
	duk_small_uint_t pause_flags;

	DUK_D(DUK_DPRINT("debug command Resume"));

	duk_debug_clear_paused(heap);

	pause_flags = 0;
#if 0  /* manual testing */
	pause_flags |= DUK_PAUSE_FLAG_ONE_OPCODE;
	pause_flags |= DUK_PAUSE_FLAG_CAUGHT_ERROR;
	pause_flags |= DUK_PAUSE_FLAG_UNCAUGHT_ERROR;
#endif
#if defined(DUK_USE_DEBUGGER_PAUSE_UNCAUGHT)
	pause_flags |= DUK_PAUSE_FLAG_UNCAUGHT_ERROR;
#endif

	duk__debug_set_pause_state(thr, heap, pause_flags);

	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_step(duk_hthread *thr, duk_heap *heap, duk_int32_t cmd) {
	duk_small_uint_t pause_flags;

	DUK_D(DUK_DPRINT("debug command StepInto/StepOver/StepOut: %d", (int) cmd));

	if (cmd == DUK_DBG_CMD_STEPINTO) {
		pause_flags = DUK_PAUSE_FLAG_LINE_CHANGE |
		              DUK_PAUSE_FLAG_FUNC_ENTRY |
		              DUK_PAUSE_FLAG_FUNC_EXIT;
	} else if (cmd == DUK_DBG_CMD_STEPOVER) {
		pause_flags = DUK_PAUSE_FLAG_LINE_CHANGE |
		              DUK_PAUSE_FLAG_FUNC_EXIT;
	} else {
		DUK_ASSERT(cmd == DUK_DBG_CMD_STEPOUT);
		pause_flags = DUK_PAUSE_FLAG_FUNC_EXIT;
	}
#if defined(DUK_USE_DEBUGGER_PAUSE_UNCAUGHT)
	pause_flags |= DUK_PAUSE_FLAG_UNCAUGHT_ERROR;
#endif

	/* If current activation doesn't have line information, line-based
	 * pause flags are automatically disabled.  As a result, e.g.
	 * StepInto will then pause on (native) function entry or exit.
	 */
	duk_debug_clear_paused(heap);
	duk__debug_set_pause_state(thr, heap, pause_flags);

	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_list_break(duk_hthread *thr, duk_heap *heap) {
	duk_small_int_t i;

	DUK_D(DUK_DPRINT("debug command ListBreak"));
	duk_debug_write_reply(thr);
	for (i = 0; i < (duk_small_int_t) heap->dbg_breakpoint_count; i++) {
		duk_debug_write_hstring(thr, heap->dbg_breakpoints[i].filename);
		duk_debug_write_uint(thr, (duk_uint32_t) heap->dbg_breakpoints[i].line);
	}
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_add_break(duk_hthread *thr, duk_heap *heap) {
	duk_hstring *filename;
	duk_uint32_t linenumber;
	duk_small_int_t idx;

	DUK_UNREF(heap);

	filename = duk_debug_read_hstring(thr);
	linenumber = (duk_uint32_t) duk_debug_read_int(thr);
	DUK_D(DUK_DPRINT("debug command AddBreak: %!O:%ld", (duk_hobject *) filename, (long) linenumber));
	idx = duk_debug_add_breakpoint(thr, filename, linenumber);
	if (idx >= 0) {
		duk_debug_write_reply(thr);
		duk_debug_write_int(thr, (duk_int32_t) idx);
		duk_debug_write_eom(thr);
	} else {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_TOOMANY, "no space for breakpoint");
	}
}

DUK_LOCAL void duk__debug_handle_del_break(duk_hthread *thr, duk_heap *heap) {
	duk_small_uint_t idx;

	DUK_UNREF(heap);

	DUK_D(DUK_DPRINT("debug command DelBreak"));
	idx = (duk_small_uint_t) duk_debug_read_int(thr);
	if (duk_debug_remove_breakpoint(thr, idx)) {
		duk_debug_write_reply(thr);
		duk_debug_write_eom(thr);
	} else {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_NOTFOUND, "invalid breakpoint index");
	}
}

DUK_LOCAL void duk__debug_handle_get_var(duk_hthread *thr, duk_heap *heap) {
	duk_activation *act;
	duk_hstring *str;
	duk_bool_t rc;

	DUK_UNREF(heap);
	DUK_D(DUK_DPRINT("debug command GetVar"));

	act = duk__debug_read_level_get_activation(thr);
	if (act == NULL) {
		return;
	}
	str = duk_debug_read_hstring(thr);  /* push to stack */
	DUK_ASSERT(str != NULL);

	rc = duk_js_getvar_activation(thr, act, str, 0);

	duk_debug_write_reply(thr);
	if (rc) {
		duk_debug_write_int(thr, 1);
		DUK_ASSERT(duk_get_tval(thr, -2) != NULL);
		duk_debug_write_tval(thr, duk_get_tval(thr, -2));
	} else {
		duk_debug_write_int(thr, 0);
		duk_debug_write_unused(thr);
	}
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_put_var(duk_hthread *thr, duk_heap *heap) {
	duk_activation *act;
	duk_hstring *str;
	duk_tval *tv;

	DUK_UNREF(heap);
	DUK_D(DUK_DPRINT("debug command PutVar"));

	act = duk__debug_read_level_get_activation(thr);
	if (act == NULL) {
		return;
	}
	str = duk_debug_read_hstring(thr);  /* push to stack */
	DUK_ASSERT(str != NULL);
	tv = duk_debug_read_tval(thr);
	if (tv == NULL) {
		/* detached */
		return;
	}

	duk_js_putvar_activation(thr, act, str, tv, 0);

	/* XXX: Current putvar implementation doesn't have a success flag,
	 * add one and send to debug client?
	 */
	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_get_call_stack(duk_hthread *thr, duk_heap *heap) {
	duk_hthread *curr_thr = thr;
	duk_activation *curr_act;
	duk_uint_fast32_t pc;
	duk_uint_fast32_t line;

	DUK_ASSERT(thr != NULL);
	DUK_UNREF(heap);

	duk_debug_write_reply(thr);
	while (curr_thr != NULL) {
		for (curr_act = curr_thr->callstack_curr; curr_act != NULL; curr_act = curr_act->parent) {
			/* PC/line semantics here are:
			 *   - For callstack top we're conceptually between two
			 *     opcodes and current PC indicates next line to
			 *     execute, so report that (matches Status).
			 *   - For other activations we're conceptually still
			 *     executing the instruction at PC-1, so report that
			 *     (matches error stacktrace behavior).
			 *   - See: https://github.com/svaarala/duktape/issues/281
			 */

			/* XXX: optimize to use direct reads, i.e. avoid
			 * value stack operations.
			 */
			duk_push_tval(thr, &curr_act->tv_func);
			duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_FILE_NAME);
			duk__debug_write_hstring_safe_top(thr);
			duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_NAME);
			duk__debug_write_hstring_safe_top(thr);
			pc = duk_hthread_get_act_curr_pc(thr, curr_act);
			if (curr_act != curr_thr->callstack_curr && pc > 0) {
				pc--;
			}
			line = duk_hobject_pc2line_query(thr, -3, pc);
			duk_debug_write_uint(thr, (duk_uint32_t) line);
			duk_debug_write_uint(thr, (duk_uint32_t) pc);
			duk_pop_3(thr);
		}
		curr_thr = curr_thr->resumer;
	}
	/* SCANBUILD: warning about 'thr' potentially being NULL here,
	 * warning is incorrect because thr != NULL always here.
	 */
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_get_locals(duk_hthread *thr, duk_heap *heap) {
	duk_activation *act;
	duk_hstring *varname;

	DUK_UNREF(heap);

	act = duk__debug_read_level_get_activation(thr);
	if (act == NULL) {
		return;
	}

	duk_debug_write_reply(thr);

	/* XXX: several nice-to-have improvements here:
	 *   - Use direct reads avoiding value stack operations
	 *   - Avoid triggering getters, indicate getter values to debug client
	 *   - If side effects are possible, add error catching
	 */

	if (DUK_TVAL_IS_OBJECT(&act->tv_func)) {
		duk_hobject *h_func = DUK_TVAL_GET_OBJECT(&act->tv_func);
		duk_hobject *h_varmap;

		h_varmap = duk_hobject_get_varmap(thr, h_func);
		if (h_varmap != NULL) {
			duk_push_hobject(thr, h_varmap);
			duk_enum(thr, -1, 0 /*enum_flags*/);
			while (duk_next(thr, -1 /*enum_index*/, 0 /*get_value*/)) {
				varname = duk_known_hstring(thr, -1);

				duk_js_getvar_activation(thr, act, varname, 0 /*throw_flag*/);
				/* [ ... func varmap enum key value this ] */
				duk_debug_write_hstring(thr, duk_get_hstring(thr, -3));
				duk_debug_write_tval(thr, duk_get_tval(thr, -2));
				duk_pop_3(thr);  /* -> [ ... func varmap enum ] */
			}
		} else {
			DUK_D(DUK_DPRINT("varmap missing in GetLocals, ignore"));
		}
	} else {
		DUK_D(DUK_DPRINT("varmap is not an object in GetLocals, ignore"));
	}

	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_eval(duk_hthread *thr, duk_heap *heap) {
	duk_small_uint_t call_flags;
	duk_int_t call_ret;
	duk_small_int_t eval_err;
	duk_bool_t direct_eval;
	duk_int32_t level;
	duk_idx_t idx_func;

	DUK_UNREF(heap);

	DUK_D(DUK_DPRINT("debug command Eval"));

	/* The eval code is executed within the lexical environment of a specified
	 * activation.  For now, use global object eval() function, with the eval
	 * considered a 'direct call to eval'.
	 *
	 * Callstack index for debug commands only affects scope -- the callstack
	 * as seen by, e.g. Duktape.act() will be the same regardless.
	 */

	/* nargs == 2 so we can pass a callstack index to eval(). */
	idx_func = duk_get_top(thr);
	duk_push_c_function(thr, duk_bi_global_object_eval, 2 /*nargs*/);
	duk_push_undefined(thr);  /* 'this' binding shouldn't matter here */

	/* Read callstack index, if non-null. */
	if (duk_debug_peek_byte(thr) == DUK_DBG_IB_NULL) {
		direct_eval = 0;
		level = -1;  /* Not needed, but silences warning. */
		(void) duk_debug_read_byte(thr);
	} else {
		direct_eval = 1;
		level = duk__debug_read_validate_csindex(thr);
		if (level == 0) {
			return;
		}
	}

	DUK_ASSERT(!direct_eval ||
	           (level < 0 && -level <= (duk_int32_t) thr->callstack_top));

	(void) duk_debug_read_hstring(thr);
	if (direct_eval) {
		duk_push_int(thr, level - 1);  /* compensate for eval() call */
	}

	/* [ ... eval "eval" eval_input level? ] */

	call_flags = 0;
	if (direct_eval) {
		duk_activation *act;
		duk_hobject *fun;

		act = duk_hthread_get_activation_for_level(thr, level);
		if (act != NULL) {
			fun = DUK_ACT_GET_FUNC(act);
			if (fun != NULL && DUK_HOBJECT_IS_COMPFUNC(fun)) {
				/* Direct eval requires that there's a current
				 * activation and it is an ECMAScript function.
				 * When Eval is executed from e.g. cooperate API
				 * call we'll need to do an indirect eval instead.
				 */
				call_flags |= DUK_CALL_FLAG_DIRECT_EVAL;
			}
		}
	}

	call_ret = duk_pcall_method_flags(thr, duk_get_top(thr) - (idx_func + 2), call_flags);

	if (call_ret == DUK_EXEC_SUCCESS) {
		eval_err = 0;
		/* Use result value as is. */
	} else {
		/* For errors a string coerced result is most informative
		 * right now, as the debug client doesn't have the capability
		 * to traverse the error object.
		 */
		eval_err = 1;
		duk_safe_to_string(thr, -1);
	}

	/* [ ... result ] */

	duk_debug_write_reply(thr);
	duk_debug_write_int(thr, (duk_int32_t) eval_err);
	DUK_ASSERT(duk_get_tval(thr, -1) != NULL);
	duk_debug_write_tval(thr, duk_get_tval(thr, -1));
	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_detach(duk_hthread *thr, duk_heap *heap) {
	DUK_UNREF(heap);
	DUK_D(DUK_DPRINT("debug command Detach"));

	duk_debug_write_reply(thr);
	duk_debug_write_eom(thr);

	DUK_D(DUK_DPRINT("debug connection detached, mark broken"));
	DUK__SET_CONN_BROKEN(thr, 0);  /* not an error */
}

DUK_LOCAL void duk__debug_handle_apprequest(duk_hthread *thr, duk_heap *heap) {
	duk_idx_t old_top;

	DUK_D(DUK_DPRINT("debug command AppRequest"));

	old_top = duk_get_top(thr);  /* save stack top */

	if (heap->dbg_request_cb != NULL) {
		duk_idx_t nrets;
		duk_idx_t nvalues = 0;
		duk_idx_t top, idx;

		/* Read tvals from the message and push them onto the valstack,
		 * then call the request callback to process the request.
		 */
		while (duk_debug_peek_byte(thr) != DUK_DBG_IB_EOM) {
			duk_tval *tv;
			if (!duk_check_stack(thr, 1)) {
				DUK_D(DUK_DPRINT("failed to allocate space for request dvalue(s)"));
				goto fail;
			}
			tv = duk_debug_read_tval(thr);  /* push to stack */
			if (tv == NULL) {
				/* detached */
				return;
			}
			nvalues++;
		}
		DUK_ASSERT(duk_get_top(thr) == old_top + nvalues);

		/* Request callback should push values for reply to client onto valstack */
		DUK_D(DUK_DPRINT("calling into AppRequest request_cb with nvalues=%ld, old_top=%ld, top=%ld",
		                 (long) nvalues, (long) old_top, (long) duk_get_top(thr)));
		nrets = heap->dbg_request_cb(thr, heap->dbg_udata, nvalues);
		DUK_D(DUK_DPRINT("returned from AppRequest request_cb; nvalues=%ld -> nrets=%ld, old_top=%ld, top=%ld",
		                 (long) nvalues, (long) nrets, (long) old_top, (long) duk_get_top(thr)));
		if (nrets >= 0) {
			DUK_ASSERT(duk_get_top(thr) >= old_top + nrets);
			if (duk_get_top(thr) < old_top + nrets) {
				DUK_D(DUK_DPRINT("AppRequest callback doesn't match value stack configuration, "
				                 "top=%ld < old_top=%ld + nrets=%ld; "
				                 "this might mean it's unsafe to continue!",
				                 (long) duk_get_top(thr), (long) old_top, (long) nrets));
				goto fail;
			}

			/* Reply with tvals pushed by request callback */
			duk_debug_write_byte(thr, DUK_DBG_IB_REPLY);
			top = duk_get_top(thr);
			for (idx = top - nrets; idx < top; idx++) {
				duk_debug_write_tval(thr, DUK_GET_TVAL_POSIDX(thr, idx));
			}
			duk_debug_write_eom(thr);
		} else {
			DUK_ASSERT(duk_get_top(thr) >= old_top + 1);
			if (duk_get_top(thr) < old_top + 1) {
				DUK_D(DUK_DPRINT("request callback return value doesn't match value stack configuration"));
				goto fail;
			}
			duk_debug_write_error_eom(thr, DUK_DBG_ERR_APPLICATION, duk_get_string(thr, -1));
		}

		duk_set_top(thr, old_top);  /* restore stack top */
	} else {
		DUK_D(DUK_DPRINT("no request callback, treat AppRequest as unsupported"));
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNSUPPORTED, "AppRequest unsupported by target");
	}

	return;

 fail:
	duk_set_top(thr, old_top);  /* restore stack top */
	DUK__SET_CONN_BROKEN(thr, 1);
}

/*
 *  DumpHeap command
 */

#if defined(DUK_USE_DEBUGGER_DUMPHEAP)
/* XXX: this has some overlap with object inspection; remove this and make
 * DumpHeap return lists of heapptrs instead?
 */
DUK_LOCAL void duk__debug_dump_heaphdr(duk_hthread *thr, duk_heap *heap, duk_heaphdr *hdr) {
	DUK_UNREF(heap);

	duk_debug_write_heapptr(thr, hdr);
	duk_debug_write_uint(thr, (duk_uint32_t) DUK_HEAPHDR_GET_TYPE(hdr));
	duk_debug_write_uint(thr, (duk_uint32_t) DUK_HEAPHDR_GET_FLAGS_RAW(hdr));
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_debug_write_uint(thr, (duk_uint32_t) DUK_HEAPHDR_GET_REFCOUNT(hdr));
#else
	duk_debug_write_int(thr, (duk_int32_t) -1);
#endif

	switch (DUK_HEAPHDR_GET_TYPE(hdr)) {
	case DUK_HTYPE_STRING: {
		duk_hstring *h = (duk_hstring *) hdr;

		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HSTRING_GET_BYTELEN(h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HSTRING_GET_CHARLEN(h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HSTRING_GET_HASH(h));
		duk_debug_write_hstring(thr, h);
		break;
	}
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h = (duk_hobject *) hdr;
		duk_hstring *k;
		duk_uint_fast32_t i;

		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_GET_CLASS_NUMBER(h));
		duk_debug_write_heapptr(thr, (duk_heaphdr *) DUK_HOBJECT_GET_PROTOTYPE(heap, h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_GET_ESIZE(h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_GET_ENEXT(h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_GET_ASIZE(h));
		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_GET_HSIZE(h));

		for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
			duk_debug_write_uint(thr, (duk_uint32_t) DUK_HOBJECT_E_GET_FLAGS(heap, h, i));
			k = DUK_HOBJECT_E_GET_KEY(heap, h, i);
			duk_debug_write_heapptr(thr, (duk_heaphdr *) k);
			if (k == NULL) {
				duk_debug_write_int(thr, 0);  /* isAccessor */
				duk_debug_write_unused(thr);
				continue;
			}
			if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(heap, h, i)) {
				duk_debug_write_int(thr, 1);  /* isAccessor */
				duk_debug_write_heapptr(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->a.get);
				duk_debug_write_heapptr(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->a.set);
			} else {
				duk_debug_write_int(thr, 0);  /* isAccessor */

				duk__debug_write_tval_heapptr(thr, &DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->v);
			}
		}

		for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(h); i++) {
			/* Note: array dump will include elements beyond
			 * 'length'.
			 */
			duk__debug_write_tval_heapptr(thr, DUK_HOBJECT_A_GET_VALUE_PTR(heap, h, i));
		}
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h = (duk_hbuffer *) hdr;

		duk_debug_write_uint(thr, (duk_uint32_t) DUK_HBUFFER_GET_SIZE(h));
		duk_debug_write_buffer(thr, (const char *) DUK_HBUFFER_GET_DATA_PTR(heap, h), (duk_size_t) DUK_HBUFFER_GET_SIZE(h));
		break;
	}
	default: {
		DUK_D(DUK_DPRINT("invalid htype: %d", (int) DUK_HEAPHDR_GET_TYPE(hdr)));
	}
	}
}

DUK_LOCAL void duk__debug_dump_heap_allocated(duk_hthread *thr, duk_heap *heap) {
	duk_heaphdr *hdr;

	hdr = heap->heap_allocated;
	while (hdr != NULL) {
		duk__debug_dump_heaphdr(thr, heap, hdr);
		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}
}

DUK_LOCAL void duk__debug_dump_strtab(duk_hthread *thr, duk_heap *heap) {
	duk_uint32_t i;
	duk_hstring *h;

	for (i = 0; i < heap->st_size; i++) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
		h = DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, heap->strtable16[i]);
#else
		h = heap->strtable[i];
#endif
		while (h != NULL) {
			duk__debug_dump_heaphdr(thr, heap, (duk_heaphdr *) h);
			h = h->hdr.h_next;
		}
	}
}

DUK_LOCAL void duk__debug_handle_dump_heap(duk_hthread *thr, duk_heap *heap) {
	DUK_D(DUK_DPRINT("debug command DumpHeap"));

	duk_debug_write_reply(thr);
	duk__debug_dump_heap_allocated(thr, heap);
	duk__debug_dump_strtab(thr, heap);
	duk_debug_write_eom(thr);
}
#endif  /* DUK_USE_DEBUGGER_DUMPHEAP */

DUK_LOCAL void duk__debug_handle_get_bytecode(duk_hthread *thr, duk_heap *heap) {
	duk_activation *act;
	duk_hcompfunc *fun = NULL;
	duk_size_t i, n;
	duk_tval *tv;
	duk_hobject **fn;
	duk_int32_t level = -1;
	duk_uint8_t ibyte;

	DUK_UNREF(heap);

	DUK_D(DUK_DPRINT("debug command GetBytecode"));

	ibyte = duk_debug_peek_byte(thr);
	if (ibyte != DUK_DBG_IB_EOM) {
		tv = duk_debug_read_tval(thr);
		if (tv == NULL) {
			/* detached */
			return;
		}
		if (DUK_TVAL_IS_OBJECT(tv)) {
			/* tentative, checked later */
			fun = (duk_hcompfunc *) DUK_TVAL_GET_OBJECT(tv);
			DUK_ASSERT(fun != NULL);
		} else if (DUK_TVAL_IS_NUMBER(tv)) {
			level = (duk_int32_t) DUK_TVAL_GET_NUMBER(tv);
		} else {
			DUK_D(DUK_DPRINT("invalid argument to GetBytecode: %!T", tv));
			goto fail_args;
		}
	}

	if (fun == NULL) {
		act = duk_hthread_get_activation_for_level(thr, level);
		if (act == NULL) {
			goto fail_index;
		}
		fun = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);
	}

	if (fun == NULL || !DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) fun)) {
		DUK_D(DUK_DPRINT("invalid argument to GetBytecode: %!O", fun));
		goto fail_args;
	}
	DUK_ASSERT(fun != NULL && DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) fun));

	duk_debug_write_reply(thr);
	n = DUK_HCOMPFUNC_GET_CONSTS_COUNT(heap, fun);
	duk_debug_write_int(thr, (duk_int32_t) n);
	tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(heap, fun);
	for (i = 0; i < n; i++) {
		duk_debug_write_tval(thr, tv);
		tv++;
	}
	n = DUK_HCOMPFUNC_GET_FUNCS_COUNT(heap, fun);
	duk_debug_write_int(thr, (duk_int32_t) n);
	fn = DUK_HCOMPFUNC_GET_FUNCS_BASE(heap, fun);
	for (i = 0; i < n; i++) {
		duk_debug_write_hobject(thr, *fn);
		fn++;
	}
	duk_debug_write_string(thr,
	                       (const char *) DUK_HCOMPFUNC_GET_CODE_BASE(heap, fun),
	                       (duk_size_t) DUK_HCOMPFUNC_GET_CODE_SIZE(heap, fun));
	duk_debug_write_eom(thr);
	return;

 fail_args:
	duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNKNOWN, "invalid argument");
	return;

 fail_index:
	duk_debug_write_error_eom(thr, DUK_DBG_ERR_NOTFOUND, "invalid callstack index");
	return;
}

/*
 *  Object inspection commands: GetHeapObjInfo, GetObjPropDesc,
 *  GetObjPropDescRange
 */

#if defined(DUK_USE_DEBUGGER_INSPECT)

#if 0 /* pruned */
DUK_LOCAL const char * const duk__debug_getinfo_heaphdr_keys[] = {
	"reachable",
	"temproot",
	"finalizable",
	"finalized",
	"readonly"
	/* NULL not needed here */
};
DUK_LOCAL duk_uint_t duk__debug_getinfo_heaphdr_masks[] = {
	DUK_HEAPHDR_FLAG_REACHABLE,
	DUK_HEAPHDR_FLAG_TEMPROOT,
	DUK_HEAPHDR_FLAG_FINALIZABLE,
	DUK_HEAPHDR_FLAG_FINALIZED,
	DUK_HEAPHDR_FLAG_READONLY,
	0  /* terminator */
};
#endif
DUK_LOCAL const char * const duk__debug_getinfo_hstring_keys[] = {
#if 0
	"arridx",
	"symbol",
	"hidden",
	"reserved_word",
	"strict_reserved_word",
	"eval_or_arguments",
#endif
	"extdata"
	/* NULL not needed here */
};
DUK_LOCAL duk_uint_t duk__debug_getinfo_hstring_masks[] = {
#if 0
	DUK_HSTRING_FLAG_ARRIDX,
	DUK_HSTRING_FLAG_SYMBOL,
	DUK_HSTRING_FLAG_HIDDEN,
	DUK_HSTRING_FLAG_RESERVED_WORD,
	DUK_HSTRING_FLAG_STRICT_RESERVED_WORD,
	DUK_HSTRING_FLAG_EVAL_OR_ARGUMENTS,
#endif
	DUK_HSTRING_FLAG_EXTDATA,
	0  /* terminator */
};
DUK_LOCAL const char * const duk__debug_getinfo_hobject_keys[] = {
	"extensible",
	"constructable",
	"callable",
	"boundfunc",
	"compfunc",
	"natfunc",
	"bufobj",
	"fastrefs",
	"array_part",
	"strict",
	"notail",
	"newenv",
	"namebinding",
	"createargs",
	"have_finalizer",
	"exotic_array",
	"exotic_stringobj",
	"exotic_arguments",
	"exotic_proxyobj",
	"special_call"
	/* NULL not needed here */
};
DUK_LOCAL duk_uint_t duk__debug_getinfo_hobject_masks[] = {
	DUK_HOBJECT_FLAG_EXTENSIBLE,
	DUK_HOBJECT_FLAG_CONSTRUCTABLE,
	DUK_HOBJECT_FLAG_CALLABLE,
	DUK_HOBJECT_FLAG_BOUNDFUNC,
	DUK_HOBJECT_FLAG_COMPFUNC,
	DUK_HOBJECT_FLAG_NATFUNC,
	DUK_HOBJECT_FLAG_BUFOBJ,
	DUK_HOBJECT_FLAG_FASTREFS,
	DUK_HOBJECT_FLAG_ARRAY_PART,
	DUK_HOBJECT_FLAG_STRICT,
	DUK_HOBJECT_FLAG_NOTAIL,
	DUK_HOBJECT_FLAG_NEWENV,
	DUK_HOBJECT_FLAG_NAMEBINDING,
	DUK_HOBJECT_FLAG_CREATEARGS,
	DUK_HOBJECT_FLAG_HAVE_FINALIZER,
	DUK_HOBJECT_FLAG_EXOTIC_ARRAY,
	DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ,
	DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS,
	DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ,
	DUK_HOBJECT_FLAG_SPECIAL_CALL,
	0  /* terminator */
};
DUK_LOCAL const char * const duk__debug_getinfo_hbuffer_keys[] = {
	"dynamic",
	"external"
	/* NULL not needed here */
};
DUK_LOCAL duk_uint_t duk__debug_getinfo_hbuffer_masks[] = {
	DUK_HBUFFER_FLAG_DYNAMIC,
	DUK_HBUFFER_FLAG_EXTERNAL,
	0  /* terminator */
};

DUK_LOCAL void duk__debug_getinfo_flags_key(duk_hthread *thr, const char *key) {
	duk_debug_write_uint(thr, 0);
	duk_debug_write_cstring(thr, key);
}

DUK_LOCAL void duk__debug_getinfo_prop_uint(duk_hthread *thr, const char *key, duk_uint_t val) {
	duk_debug_write_uint(thr, 0);
	duk_debug_write_cstring(thr, key);
	duk_debug_write_uint(thr, val);
}

DUK_LOCAL void duk__debug_getinfo_prop_int(duk_hthread *thr, const char *key, duk_int_t val) {
	duk_debug_write_uint(thr, 0);
	duk_debug_write_cstring(thr, key);
	duk_debug_write_int(thr, val);
}

DUK_LOCAL void duk__debug_getinfo_prop_bool(duk_hthread *thr, const char *key, duk_bool_t val) {
	duk_debug_write_uint(thr, 0);
	duk_debug_write_cstring(thr, key);
	duk_debug_write_boolean(thr, val);
}

DUK_LOCAL void duk__debug_getinfo_bitmask(duk_hthread *thr, const char * const * keys, duk_uint_t *masks, duk_uint_t flags) {
	const char *key;
	duk_uint_t mask;

	for (;;) {
		mask = *masks++;
		if (mask == 0) {
			break;
		}
		key = *keys++;
		DUK_ASSERT(key != NULL);

		DUK_DD(DUK_DDPRINT("inspect bitmask: key=%s, mask=0x%08lx, flags=0x%08lx", key, (unsigned long) mask, (unsigned long) flags));
		duk__debug_getinfo_prop_bool(thr, key, flags & mask);
	}
}

/* Inspect a property using a virtual index into a conceptual property list
 * consisting of (1) all array part items from [0,a_size[ (even when above
 * .length) and (2) all entry part items from [0,e_next[.  Unused slots are
 * indicated using dvalue 'unused'.
 */
DUK_LOCAL duk_bool_t duk__debug_getprop_index(duk_hthread *thr, duk_heap *heap, duk_hobject *h_obj, duk_uint_t idx) {
	duk_uint_t a_size;
	duk_tval *tv;
	duk_hstring *h_key;
	duk_hobject *h_getset;
	duk_uint_t flags;

	DUK_UNREF(heap);

	a_size = DUK_HOBJECT_GET_ASIZE(h_obj);
	if (idx < a_size) {
		duk_debug_write_uint(thr, DUK_PROPDESC_FLAGS_WEC);
		duk_debug_write_uint(thr, idx);
		tv = DUK_HOBJECT_A_GET_VALUE_PTR(heap, h_obj, idx);
		duk_debug_write_tval(thr, tv);
		return 1;
	}

	idx -= a_size;
	if (idx >= DUK_HOBJECT_GET_ENEXT(h_obj)) {
		return 0;
	}

	h_key = DUK_HOBJECT_E_GET_KEY(heap, h_obj, idx);
	if (h_key == NULL) {
		duk_debug_write_uint(thr, 0);
		duk_debug_write_null(thr);
		duk_debug_write_unused(thr);
		return 1;
	}

	flags = DUK_HOBJECT_E_GET_FLAGS(heap, h_obj, idx);
	if (DUK_HSTRING_HAS_SYMBOL(h_key)) {
		flags |= DUK_DBG_PROPFLAG_SYMBOL;
	}
	if (DUK_HSTRING_HAS_HIDDEN(h_key)) {
		flags |= DUK_DBG_PROPFLAG_HIDDEN;
	}
	duk_debug_write_uint(thr, flags);
	duk_debug_write_hstring(thr, h_key);
	if (flags & DUK_PROPDESC_FLAG_ACCESSOR) {
		h_getset = DUK_HOBJECT_E_GET_VALUE_GETTER(heap, h_obj, idx);
		if (h_getset) {
			duk_debug_write_hobject(thr, h_getset);
		} else {
			duk_debug_write_null(thr);
		}
		h_getset = DUK_HOBJECT_E_GET_VALUE_SETTER(heap, h_obj, idx);
		if (h_getset) {
			duk_debug_write_hobject(thr, h_getset);
		} else {
			duk_debug_write_null(thr);
		}
	} else {
		tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(heap, h_obj, idx);
		duk_debug_write_tval(thr, tv);
	}
	return 1;
}

DUK_LOCAL void duk__debug_handle_get_heap_obj_info(duk_hthread *thr, duk_heap *heap) {
	duk_heaphdr *h;

	DUK_D(DUK_DPRINT("debug command GetHeapObjInfo"));
	DUK_UNREF(heap);

	DUK_ASSERT(sizeof(duk__debug_getinfo_hstring_keys) / sizeof(const char *) == sizeof(duk__debug_getinfo_hstring_masks) / sizeof(duk_uint_t) - 1);
	DUK_ASSERT(sizeof(duk__debug_getinfo_hobject_keys) / sizeof(const char *) == sizeof(duk__debug_getinfo_hobject_masks) / sizeof(duk_uint_t) - 1);
	DUK_ASSERT(sizeof(duk__debug_getinfo_hbuffer_keys) / sizeof(const char *) == sizeof(duk__debug_getinfo_hbuffer_masks) / sizeof(duk_uint_t) - 1);

	h = duk_debug_read_any_ptr(thr);
	if (!h) {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNKNOWN, "invalid target");
		return;
	}

	duk_debug_write_reply(thr);

	/* As with all inspection code, we rely on the debug client providing
	 * a valid, non-stale pointer: there's no portable way to safely
	 * validate the pointer here.
	 */

	duk__debug_getinfo_flags_key(thr, "heapptr");
	duk_debug_write_heapptr(thr, h);

	/* XXX: comes out as signed now */
	duk__debug_getinfo_prop_uint(thr, "heaphdr_flags", (duk_uint_t) DUK_HEAPHDR_GET_FLAGS(h));
	duk__debug_getinfo_prop_uint(thr, "heaphdr_type", (duk_uint_t) DUK_HEAPHDR_GET_TYPE(h));
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__debug_getinfo_prop_uint(thr, "refcount", (duk_uint_t) DUK_HEAPHDR_GET_REFCOUNT(h));
#endif
#if 0 /* pruned */
	duk__debug_getinfo_bitmask(thr,
	                           duk__debug_getinfo_heaphdr_keys,
	                           duk__debug_getinfo_heaphdr_masks,
	                           DUK_HEAPHDR_GET_FLAGS_RAW(h));
#endif

	switch (DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING: {
		duk_hstring *h_str;

		h_str = (duk_hstring *) h;
		duk__debug_getinfo_bitmask(thr,
		                           duk__debug_getinfo_hstring_keys,
		                           duk__debug_getinfo_hstring_masks,
		                           DUK_HEAPHDR_GET_FLAGS_RAW(h));
		duk__debug_getinfo_prop_uint(thr, "bytelen", (duk_uint_t) DUK_HSTRING_GET_BYTELEN(h_str));
		duk__debug_getinfo_prop_uint(thr, "charlen", (duk_uint_t) DUK_HSTRING_GET_CHARLEN(h_str));
		duk__debug_getinfo_prop_uint(thr, "hash", (duk_uint_t) DUK_HSTRING_GET_HASH(h_str));
		duk__debug_getinfo_flags_key(thr, "data");
		duk_debug_write_hstring(thr, h_str);
		break;
	}
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h_obj;
		duk_hobject *h_proto;

		h_obj = (duk_hobject *) h;
		h_proto = DUK_HOBJECT_GET_PROTOTYPE(heap, h_obj);

		/* duk_hobject specific fields. */
		duk__debug_getinfo_bitmask(thr,
		                           duk__debug_getinfo_hobject_keys,
		                           duk__debug_getinfo_hobject_masks,
		                           DUK_HEAPHDR_GET_FLAGS_RAW(h));
		duk__debug_getinfo_prop_uint(thr, "class_number", DUK_HOBJECT_GET_CLASS_NUMBER(h_obj));
		duk__debug_getinfo_flags_key(thr, "class_name");
		duk_debug_write_hstring(thr, DUK_HOBJECT_GET_CLASS_STRING(heap, h_obj));
		duk__debug_getinfo_flags_key(thr, "prototype");
		if (h_proto != NULL) {
			duk_debug_write_hobject(thr, h_proto);
		} else {
			duk_debug_write_null(thr);
		}
		duk__debug_getinfo_flags_key(thr, "props");
		duk_debug_write_pointer(thr, (void *) DUK_HOBJECT_GET_PROPS(heap, h_obj));
		duk__debug_getinfo_prop_uint(thr, "e_size", (duk_uint_t) DUK_HOBJECT_GET_ESIZE(h_obj));
		duk__debug_getinfo_prop_uint(thr, "e_next", (duk_uint_t) DUK_HOBJECT_GET_ENEXT(h_obj));
		duk__debug_getinfo_prop_uint(thr, "a_size", (duk_uint_t) DUK_HOBJECT_GET_ASIZE(h_obj));
		duk__debug_getinfo_prop_uint(thr, "h_size", (duk_uint_t) DUK_HOBJECT_GET_HSIZE(h_obj));

		if (DUK_HOBJECT_IS_ARRAY(h_obj)) {
			duk_harray *h_arr;
			h_arr = (duk_harray *) h_obj;

			duk__debug_getinfo_prop_uint(thr, "length", (duk_uint_t) h_arr->length);
			duk__debug_getinfo_prop_bool(thr, "length_nonwritable", h_arr->length_nonwritable);
		}

		if (DUK_HOBJECT_IS_NATFUNC(h_obj)) {
			duk_hnatfunc *h_fun;
			h_fun = (duk_hnatfunc *) h_obj;

			duk__debug_getinfo_prop_int(thr, "nargs", h_fun->nargs);
			duk__debug_getinfo_prop_int(thr, "magic", h_fun->magic);
			duk__debug_getinfo_prop_bool(thr, "varargs", h_fun->magic == DUK_HNATFUNC_NARGS_VARARGS);
			/* Native function pointer may be different from a void pointer,
			 * and we serialize it from memory directly now (no byte swapping etc).
			 */
			duk__debug_getinfo_flags_key(thr, "funcptr");
			duk_debug_write_buffer(thr, (const char *) &h_fun->func, sizeof(h_fun->func));
		}

		if (DUK_HOBJECT_IS_COMPFUNC(h_obj)) {
			duk_hcompfunc *h_fun;
			duk_hbuffer *h_buf;
			duk_hobject *h_lexenv;
			duk_hobject *h_varenv;
			h_fun = (duk_hcompfunc *) h_obj;

			duk__debug_getinfo_prop_int(thr, "nregs", h_fun->nregs);
			duk__debug_getinfo_prop_int(thr, "nargs", h_fun->nargs);

			duk__debug_getinfo_flags_key(thr, "lex_env");
			h_lexenv = DUK_HCOMPFUNC_GET_LEXENV(thr->heap, h_fun);
			if (h_lexenv != NULL) {
				duk_debug_write_hobject(thr, h_lexenv);
			} else {
				duk_debug_write_null(thr);
			}
			duk__debug_getinfo_flags_key(thr, "var_env");
			h_varenv = DUK_HCOMPFUNC_GET_VARENV(thr->heap, h_fun);
			if (h_varenv != NULL) {
				duk_debug_write_hobject(thr, h_varenv);
			} else {
				duk_debug_write_null(thr);
			}

			duk__debug_getinfo_prop_uint(thr, "start_line", h_fun->start_line);
			duk__debug_getinfo_prop_uint(thr, "end_line", h_fun->end_line);
			h_buf = (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(thr->heap, h_fun);
			if (h_buf != NULL) {
				duk__debug_getinfo_flags_key(thr, "data");
				duk_debug_write_heapptr(thr, (duk_heaphdr *) h_buf);
			}
		}

		if (DUK_HOBJECT_IS_BOUNDFUNC(h_obj)) {
			duk_hboundfunc *h_bfun;
			h_bfun = (duk_hboundfunc *) (void *) h_obj;

			duk__debug_getinfo_flags_key(thr, "target");
			duk_debug_write_tval(thr, &h_bfun->target);
			duk__debug_getinfo_flags_key(thr, "this_binding");
			duk_debug_write_tval(thr, &h_bfun->this_binding);
			duk__debug_getinfo_flags_key(thr, "nargs");
			duk_debug_write_int(thr, h_bfun->nargs);
			/* h_bfun->args not exposed now */
		}

		if (DUK_HOBJECT_IS_THREAD(h_obj)) {
			/* XXX: Currently no inspection of threads, e.g. value stack, call
			 * stack, catch stack, etc.
			 */
			duk_hthread *h_thr;
			h_thr = (duk_hthread *) h_obj;
			DUK_UNREF(h_thr);
		}

		if (DUK_HOBJECT_IS_DECENV(h_obj)) {
			duk_hdecenv *h_env;
			h_env = (duk_hdecenv *) h_obj;

			duk__debug_getinfo_flags_key(thr, "thread");
			duk_debug_write_heapptr(thr, (duk_heaphdr *) (h_env->thread));
			duk__debug_getinfo_flags_key(thr, "varmap");
			duk_debug_write_heapptr(thr, (duk_heaphdr *) (h_env->varmap));
			duk__debug_getinfo_prop_uint(thr, "regbase", (duk_uint_t) h_env->regbase_byteoff);
		}

		if (DUK_HOBJECT_IS_OBJENV(h_obj)) {
			duk_hobjenv *h_env;
			h_env = (duk_hobjenv *) h_obj;

			duk__debug_getinfo_flags_key(thr, "target");
			duk_debug_write_heapptr(thr, (duk_heaphdr *) (h_env->target));
			duk__debug_getinfo_prop_bool(thr, "has_this", h_env->has_this);
		}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		if (DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
			duk_hbufobj *h_bufobj;
			h_bufobj = (duk_hbufobj *) h_obj;

			duk__debug_getinfo_prop_uint(thr, "slice_offset", h_bufobj->offset);
			duk__debug_getinfo_prop_uint(thr, "slice_length", h_bufobj->length);
			duk__debug_getinfo_prop_uint(thr, "elem_shift", (duk_uint_t) h_bufobj->shift);
			duk__debug_getinfo_prop_uint(thr, "elem_type", (duk_uint_t) h_bufobj->elem_type);
			duk__debug_getinfo_prop_bool(thr, "is_typedarray", (duk_uint_t) h_bufobj->is_typedarray);
			if (h_bufobj->buf != NULL) {
				duk__debug_getinfo_flags_key(thr, "buffer");
				duk_debug_write_heapptr(thr, (duk_heaphdr *) h_bufobj->buf);
			}
		}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h_buf;

		h_buf = (duk_hbuffer *) h;
		duk__debug_getinfo_bitmask(thr,
		                           duk__debug_getinfo_hbuffer_keys,
		                           duk__debug_getinfo_hbuffer_masks,
		                           DUK_HEAPHDR_GET_FLAGS_RAW(h));
		duk__debug_getinfo_prop_uint(thr, "size", (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_buf));
		duk__debug_getinfo_flags_key(thr, "dataptr");
		duk_debug_write_pointer(thr, (void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_buf));
		duk__debug_getinfo_flags_key(thr, "data");
		duk_debug_write_hbuffer(thr, h_buf);  /* tolerates NULL h_buf */
		break;
	}
	default: {
		/* Since we already started writing the reply, just emit nothing. */
		DUK_D(DUK_DPRINT("inspect target pointer has invalid heaphdr type"));
	}
	}

	duk_debug_write_eom(thr);
}

DUK_LOCAL void duk__debug_handle_get_obj_prop_desc(duk_hthread *thr, duk_heap *heap) {
	duk_heaphdr *h;
	duk_hobject *h_obj;
	duk_hstring *h_key;
	duk_propdesc desc;

	DUK_D(DUK_DPRINT("debug command GetObjPropDesc"));
	DUK_UNREF(heap);

	h = duk_debug_read_any_ptr(thr);
	if (!h) {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNKNOWN, "invalid target");
		return;
	}
	h_key = duk_debug_read_hstring(thr);
	if (h == NULL || DUK_HEAPHDR_GET_TYPE(h) != DUK_HTYPE_OBJECT || h_key == NULL) {
		goto fail_args;
	}
	h_obj = (duk_hobject *) h;

	if (duk_hobject_get_own_propdesc(thr, h_obj, h_key, &desc, 0 /*flags*/)) {
		duk_int_t virtual_idx;
		duk_bool_t rc;

		/* To use the shared helper need the virtual index. */
		DUK_ASSERT(desc.e_idx >= 0 || desc.a_idx >= 0);
		virtual_idx = (desc.a_idx >= 0 ? desc.a_idx :
		               (duk_int_t) DUK_HOBJECT_GET_ASIZE(h_obj) + desc.e_idx);

		duk_debug_write_reply(thr);
		rc = duk__debug_getprop_index(thr, heap, h_obj, (duk_uint_t) virtual_idx);
		DUK_ASSERT(rc == 1);
		DUK_UNREF(rc);
		duk_debug_write_eom(thr);
	} else {
		duk_debug_write_error_eom(thr, DUK_DBG_ERR_NOTFOUND, "not found");
	}
	return;

 fail_args:
	duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNKNOWN, "invalid args");
}

DUK_LOCAL void duk__debug_handle_get_obj_prop_desc_range(duk_hthread *thr, duk_heap *heap) {
	duk_heaphdr *h;
	duk_hobject *h_obj;
	duk_uint_t idx, idx_start, idx_end;

	DUK_D(DUK_DPRINT("debug command GetObjPropDescRange"));
	DUK_UNREF(heap);

	h = duk_debug_read_any_ptr(thr);
	idx_start = (duk_uint_t) duk_debug_read_int(thr);
	idx_end = (duk_uint_t) duk_debug_read_int(thr);
	if (h == NULL || DUK_HEAPHDR_GET_TYPE(h) != DUK_HTYPE_OBJECT) {
		goto fail_args;
	}
	h_obj = (duk_hobject *) h;

	/* The index range space is conceptually the array part followed by the
	 * entry part.  Unlike normal enumeration all slots are exposed here as
	 * is and return 'unused' if the slots are not in active use.  In particular
	 * the array part is included for the full a_size regardless of what the
	 * array .length is.
	 */

	duk_debug_write_reply(thr);
	for (idx = idx_start; idx < idx_end; idx++) {
		if (!duk__debug_getprop_index(thr, heap, h_obj, idx)) {
			break;
		}
	}
	duk_debug_write_eom(thr);
	return;

 fail_args:
	duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNKNOWN, "invalid args");
}

#endif  /* DUK_USE_DEBUGGER_INSPECT */

/*
 *  Process incoming debug requests
 *
 *  Individual request handlers can push temporaries on the value stack and
 *  rely on duk__debug_process_message() to restore the value stack top
 *  automatically.
 */

/* Process one debug message.  Automatically restore value stack top to its
 * entry value, so that individual message handlers don't need exact value
 * stack handling which is convenient.
 */
DUK_LOCAL void duk__debug_process_message(duk_hthread *thr) {
	duk_heap *heap;
	duk_uint8_t x;
	duk_int32_t cmd;
	duk_idx_t entry_top;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	entry_top = duk_get_top(thr);

	x = duk_debug_read_byte(thr);
	switch (x) {
	case DUK_DBG_IB_REQUEST: {
		cmd = duk_debug_read_int(thr);
		switch (cmd) {
		case DUK_DBG_CMD_BASICINFO: {
			duk__debug_handle_basic_info(thr, heap);
			break;
		}
		case DUK_DBG_CMD_TRIGGERSTATUS: {
			duk__debug_handle_trigger_status(thr, heap);
			break;
		}
		case DUK_DBG_CMD_PAUSE: {
			duk__debug_handle_pause(thr, heap);
			break;
		}
		case DUK_DBG_CMD_RESUME: {
			duk__debug_handle_resume(thr, heap);
			break;
		}
		case DUK_DBG_CMD_STEPINTO:
		case DUK_DBG_CMD_STEPOVER:
		case DUK_DBG_CMD_STEPOUT: {
			duk__debug_handle_step(thr, heap, cmd);
			break;
		}
		case DUK_DBG_CMD_LISTBREAK: {
			duk__debug_handle_list_break(thr, heap);
			break;
		}
		case DUK_DBG_CMD_ADDBREAK: {
			duk__debug_handle_add_break(thr, heap);
			break;
		}
		case DUK_DBG_CMD_DELBREAK: {
			duk__debug_handle_del_break(thr, heap);
			break;
		}
		case DUK_DBG_CMD_GETVAR: {
			duk__debug_handle_get_var(thr, heap);
			break;
		}
		case DUK_DBG_CMD_PUTVAR: {
			duk__debug_handle_put_var(thr, heap);
			break;
		}
		case DUK_DBG_CMD_GETCALLSTACK: {
			duk__debug_handle_get_call_stack(thr, heap);
			break;
		}
		case DUK_DBG_CMD_GETLOCALS: {
			duk__debug_handle_get_locals(thr, heap);
			break;
		}
		case DUK_DBG_CMD_EVAL: {
			duk__debug_handle_eval(thr, heap);
			break;
		}
		case DUK_DBG_CMD_DETACH: {
			/* The actual detached_cb call is postponed to message loop so
			 * we don't need any special precautions here (just skip to EOM
			 * on the already closed connection).
			 */
			duk__debug_handle_detach(thr, heap);
			break;
		}
#if defined(DUK_USE_DEBUGGER_DUMPHEAP)
		case DUK_DBG_CMD_DUMPHEAP: {
			duk__debug_handle_dump_heap(thr, heap);
			break;
		}
#endif  /* DUK_USE_DEBUGGER_DUMPHEAP */
		case DUK_DBG_CMD_GETBYTECODE: {
			duk__debug_handle_get_bytecode(thr, heap);
			break;
		}
		case DUK_DBG_CMD_APPREQUEST: {
			duk__debug_handle_apprequest(thr, heap);
			break;
		}
#if defined(DUK_USE_DEBUGGER_INSPECT)
		case DUK_DBG_CMD_GETHEAPOBJINFO: {
			duk__debug_handle_get_heap_obj_info(thr, heap);
			break;
		}
		case DUK_DBG_CMD_GETOBJPROPDESC: {
			duk__debug_handle_get_obj_prop_desc(thr, heap);
			break;
		}
		case DUK_DBG_CMD_GETOBJPROPDESCRANGE: {
			duk__debug_handle_get_obj_prop_desc_range(thr, heap);
			break;
		}
#endif  /* DUK_USE_DEBUGGER_INSPECT */
		default: {
			DUK_D(DUK_DPRINT("debug command unsupported: %d", (int) cmd));
			duk_debug_write_error_eom(thr, DUK_DBG_ERR_UNSUPPORTED, "unsupported command");
		}
		}  /* switch cmd */
		break;
	}
	case DUK_DBG_IB_REPLY: {
		DUK_D(DUK_DPRINT("debug reply, skipping"));
		break;
	}
	case DUK_DBG_IB_ERROR: {
		DUK_D(DUK_DPRINT("debug error, skipping"));
		break;
	}
	case DUK_DBG_IB_NOTIFY: {
		DUK_D(DUK_DPRINT("debug notify, skipping"));
		break;
	}
	default: {
		DUK_D(DUK_DPRINT("invalid initial byte, drop connection: %d", (int) x));
		goto fail;
	}
	}  /* switch initial byte */

	DUK_ASSERT(duk_get_top(thr) >= entry_top);
	duk_set_top(thr, entry_top);
	duk__debug_skip_to_eom(thr);
	return;

 fail:
	DUK_ASSERT(duk_get_top(thr) >= entry_top);
	duk_set_top(thr, entry_top);
	DUK__SET_CONN_BROKEN(thr, 1);
	return;
}

DUK_LOCAL void duk__check_resend_status(duk_hthread *thr) {
	if (thr->heap->dbg_read_cb != NULL && thr->heap->dbg_state_dirty) {
		duk_debug_send_status(thr);
		thr->heap->dbg_state_dirty = 0;
	}
}

DUK_INTERNAL duk_bool_t duk_debug_process_messages(duk_hthread *thr, duk_bool_t no_block) {
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t entry_top;
#endif
	duk_bool_t retval = 0;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(thr);
#endif

	DUK_D(DUK_DPRINT("process debug messages: read_cb=%s, no_block=%ld, detaching=%ld, processing=%ld",
	                 thr->heap->dbg_read_cb ? "not NULL" : "NULL", (long) no_block,
	                 (long) thr->heap->dbg_detaching, (long) thr->heap->dbg_processing));
	DUK_DD(DUK_DDPRINT("top at entry: %ld", (long) duk_get_top(thr)));

	/* thr->heap->dbg_detaching may be != 0 if a debugger write outside
	 * the message loop caused a transport error and detach1() to run.
	 */
	DUK_ASSERT(thr->heap->dbg_detaching == 0 || thr->heap->dbg_detaching == 1);
	DUK_ASSERT(thr->heap->dbg_processing == 0);
	thr->heap->dbg_processing = 1;

	/* Ensure dirty state causes a Status even if never process any
	 * messages.  This is expected by the bytecode executor when in
	 * the running state.
	 */
	duk__check_resend_status(thr);

	for (;;) {
		/* Process messages until we're no longer paused or we peek
		 * and see there's nothing to read right now.
		 */
		DUK_DD(DUK_DDPRINT("top at loop top: %ld", (long) duk_get_top(thr)));
		DUK_ASSERT(thr->heap->dbg_processing == 1);

		while (thr->heap->dbg_read_cb == NULL && thr->heap->dbg_detaching) {
			/* Detach is pending; can be triggered from outside the
			 * debugger loop (e.g. Status notify write error) or by
			 * previous message handling.  Call detached callback
			 * here, in a controlled state, to ensure a possible
			 * reattach inside the detached_cb is handled correctly.
			 *
			 * Recheck for detach in a while loop: an immediate
			 * reattach involves a call to duk_debugger_attach()
			 * which writes a debugger handshake line immediately
			 * inside the API call.  If the transport write fails
			 * for that handshake, we can immediately end up in a
			 * "transport broken, detaching" case several times here.
			 * Loop back until we're either cleanly attached or
			 * fully detached.
			 *
			 * NOTE: Reset dbg_processing = 1 forcibly, in case we
			 * re-attached; duk_debugger_attach() sets dbg_processing
			 * to 0 at the moment.
			 */

			DUK_D(DUK_DPRINT("detach pending (dbg_read_cb == NULL, dbg_detaching != 0), call detach2"));

			duk__debug_do_detach2(thr->heap);
			thr->heap->dbg_processing = 1;  /* may be set to 0 by duk_debugger_attach() inside callback */

			DUK_D(DUK_DPRINT("after detach2 (and possible reattach): dbg_read_cb=%s, dbg_detaching=%ld",
			                 thr->heap->dbg_read_cb ? "not NULL" : "NULL", (long) thr->heap->dbg_detaching));
		}
		DUK_ASSERT(thr->heap->dbg_detaching == 0);  /* true even with reattach */
		DUK_ASSERT(thr->heap->dbg_processing == 1);  /* even after a detach and possible reattach */

		if (thr->heap->dbg_read_cb == NULL) {
			DUK_D(DUK_DPRINT("debug connection broken (and not detaching), stop processing messages"));
			break;
		}

		if (!DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap) || no_block) {
			if (!duk_debug_read_peek(thr)) {
				/* Note: peek cannot currently trigger a detach
				 * so the dbg_detaching == 0 assert outside the
				 * loop is correct.
				 */
				DUK_D(DUK_DPRINT("processing debug message, peek indicated no data, stop processing messages"));
				break;
			}
			DUK_D(DUK_DPRINT("processing debug message, peek indicated there is data, handle it"));
		} else {
			DUK_D(DUK_DPRINT("paused, process debug message, blocking if necessary"));
		}

		duk__check_resend_status(thr);
		duk__debug_process_message(thr);
		duk__check_resend_status(thr);

		retval = 1;  /* processed one or more messages */
	}

	DUK_ASSERT(thr->heap->dbg_detaching == 0);
	DUK_ASSERT(thr->heap->dbg_processing == 1);
	thr->heap->dbg_processing = 0;

	/* As an initial implementation, read flush after exiting the message
	 * loop.  If transport is broken, this is a no-op (with debug logs).
	 */
	duk_debug_read_flush(thr);  /* this cannot initiate a detach */
	DUK_ASSERT(thr->heap->dbg_detaching == 0);

	DUK_DD(DUK_DDPRINT("top at exit: %ld", (long) duk_get_top(thr)));

#if defined(DUK_USE_ASSERTIONS)
	/* Easy to get wrong, so assert for it. */
	DUK_ASSERT(entry_top == duk_get_top(thr));
#endif

	return retval;
}

/*
 *  Halt execution helper
 */

/* Halt execution and enter a debugger message loop until execution is resumed
 * by the client.  PC for the current activation may be temporarily decremented
 * so that the "current" instruction will be shown by the client.  This helper
 * is callable from anywhere, also outside bytecode executor.
 */

DUK_INTERNAL void duk_debug_halt_execution(duk_hthread *thr, duk_bool_t use_prev_pc) {
	duk_activation *act;
	duk_hcompfunc *fun;
	duk_instr_t *old_pc = NULL;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(duk_debug_is_attached(thr->heap));
	DUK_ASSERT(thr->heap->dbg_processing == 0);
	DUK_ASSERT(!duk_debug_is_paused(thr->heap));

	duk_debug_set_paused(thr->heap);

	act = thr->callstack_curr;

	/* NOTE: act may be NULL if an error is thrown outside of any activation,
	 * which may happen in the case of, e.g. syntax errors.
	 */

	/* Decrement PC if that was requested, this requires a PC sync. */
	if (act != NULL) {
		duk_hthread_sync_currpc(thr);
		old_pc = act->curr_pc;
		fun = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);

		/* Short circuit if is safe: if act->curr_pc != NULL, 'fun' is
		 * guaranteed to be a non-NULL ECMAScript function.
		 */
		DUK_ASSERT(act->curr_pc == NULL ||
		           (fun != NULL && DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) fun)));
		if (use_prev_pc &&
		    act->curr_pc != NULL &&
		    act->curr_pc > DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, fun)) {
			act->curr_pc--;
		}
	}

	/* Process debug messages until we are no longer paused. */

	/* NOTE: This is a bit fragile.  It's important to ensure that
	 * duk_debug_process_messages() never throws an error or
	 * act->curr_pc will never be reset.
	 */

	thr->heap->dbg_state_dirty = 1;
	while (DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap)) {
		DUK_ASSERT(duk_debug_is_attached(thr->heap));
		DUK_ASSERT(thr->heap->dbg_processing == 0);
		duk_debug_process_messages(thr, 0 /*no_block*/);
	}

	/* XXX: Decrementing and restoring act->curr_pc works now, but if the
	 * debugger message loop gains the ability to adjust the current PC
	 * (e.g. a forced jump) restoring the PC here will break.  Another
	 * approach would be to use a state flag for the "decrement 1 from
	 * topmost activation's PC" and take it into account whenever dealing
	 * with PC values.
	 */
	if (act != NULL) {
		act->curr_pc = old_pc;  /* restore PC */
	}
}

/*
 *  Breakpoint management
 */

DUK_INTERNAL duk_small_int_t duk_debug_add_breakpoint(duk_hthread *thr, duk_hstring *filename, duk_uint32_t line) {
	duk_heap *heap;
	duk_breakpoint *b;

	/* Caller must trigger recomputation of active breakpoint list.  To
	 * ensure stale values are not used if that doesn't happen, clear the
	 * active breakpoint list here.
	 */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(filename != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);

	if (heap->dbg_breakpoint_count >= DUK_HEAP_MAX_BREAKPOINTS) {
		DUK_D(DUK_DPRINT("failed to add breakpoint for %O:%ld, all breakpoint slots used",
		                 (duk_heaphdr *) filename, (long) line));
		return -1;
	}
	heap->dbg_breakpoints_active[0] = (duk_breakpoint *) NULL;
	b = heap->dbg_breakpoints + (heap->dbg_breakpoint_count++);
	b->filename = filename;
	b->line = line;
	DUK_HSTRING_INCREF(thr, filename);

	return (duk_small_int_t) (heap->dbg_breakpoint_count - 1);  /* index */
}

DUK_INTERNAL duk_bool_t duk_debug_remove_breakpoint(duk_hthread *thr, duk_small_uint_t breakpoint_index) {
	duk_heap *heap;
	duk_hstring *h;
	duk_breakpoint *b;
	duk_size_t move_size;

	/* Caller must trigger recomputation of active breakpoint list.  To
	 * ensure stale values are not used if that doesn't happen, clear the
	 * active breakpoint list here.
	 */

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(duk_debug_is_attached(thr->heap));
	DUK_ASSERT_DISABLE(breakpoint_index >= 0);  /* unsigned */

	if (breakpoint_index >= heap->dbg_breakpoint_count) {
		DUK_D(DUK_DPRINT("invalid breakpoint index: %ld", (long) breakpoint_index));
		return 0;
	}
	b = heap->dbg_breakpoints + breakpoint_index;

	h = b->filename;
	DUK_ASSERT(h != NULL);

	move_size = sizeof(duk_breakpoint) * (heap->dbg_breakpoint_count - breakpoint_index - 1);
	duk_memmove((void *) b,
	            (const void *) (b + 1),
	            (size_t) move_size);

	heap->dbg_breakpoint_count--;
	heap->dbg_breakpoints_active[0] = (duk_breakpoint *) NULL;

	DUK_HSTRING_DECREF(thr, h);  /* side effects */
	DUK_UNREF(h);  /* w/o refcounting */

	/* Breakpoint entries above the used area are left as garbage. */

	return 1;
}

/*
 *  Misc state management
 */

DUK_INTERNAL duk_bool_t duk_debug_is_attached(duk_heap *heap) {
	return (heap->dbg_read_cb != NULL);
}

DUK_INTERNAL duk_bool_t duk_debug_is_paused(duk_heap *heap) {
	return (DUK_HEAP_HAS_DEBUGGER_PAUSED(heap) != 0);
}

DUK_INTERNAL void duk_debug_set_paused(duk_heap *heap) {
	if (duk_debug_is_paused(heap)) {
		DUK_D(DUK_DPRINT("trying to set paused state when already paused, ignoring"));
	} else {
		DUK_HEAP_SET_DEBUGGER_PAUSED(heap);
		heap->dbg_state_dirty = 1;
		duk_debug_clear_pause_state(heap);
		DUK_ASSERT(heap->ms_running == 0);  /* debugger can't be triggered within mark-and-sweep */
		heap->ms_running = 2;  /* prevent mark-and-sweep, prevent refzero queueing */
		heap->ms_prevent_count++;
		DUK_ASSERT(heap->ms_prevent_count != 0);  /* Wrap. */
		DUK_ASSERT(heap->heap_thread != NULL);
	}
}

DUK_INTERNAL void duk_debug_clear_paused(duk_heap *heap) {
	if (duk_debug_is_paused(heap)) {
		DUK_HEAP_CLEAR_DEBUGGER_PAUSED(heap);
		heap->dbg_state_dirty = 1;
		duk_debug_clear_pause_state(heap);
		DUK_ASSERT(heap->ms_running == 2);
		DUK_ASSERT(heap->ms_prevent_count > 0);
		heap->ms_prevent_count--;
		heap->ms_running = 0;
		DUK_ASSERT(heap->heap_thread != NULL);
	} else {
		DUK_D(DUK_DPRINT("trying to clear paused state when not paused, ignoring"));
	}
}

DUK_INTERNAL void duk_debug_clear_pause_state(duk_heap *heap) {
	heap->dbg_pause_flags = 0;
	heap->dbg_pause_act = NULL;
	heap->dbg_pause_startline = 0;
}

#else  /* DUK_USE_DEBUGGER_SUPPORT */

/* No debugger support. */

#endif  /* DUK_USE_DEBUGGER_SUPPORT */

/* automatic undefs */
#undef DUK__DBG_TPORT_ENTER
#undef DUK__DBG_TPORT_EXIT
#undef DUK__SET_CONN_BROKEN
/*
 *  Augmenting errors at their creation site and their throw site.
 *
 *  When errors are created, traceback data is added by built-in code
 *  and a user error handler (if defined) can process or replace the
 *  error.  Similarly, when errors are thrown, a user error handler
 *  (if defined) can process or replace the error.
 *
 *  Augmentation and other processing at error creation time is nice
 *  because an error is only created once, but it may be thrown and
 *  rethrown multiple times.  User error handler registered for processing
 *  an error at its throw site must be careful to handle rethrowing in
 *  a useful manner.
 *
 *  Error augmentation may throw an internal error (e.g. alloc error).
 *
 *  ECMAScript allows throwing any values, so all values cannot be
 *  augmented.  Currently, the built-in augmentation at error creation
 *  only augments error values which are Error instances (= have the
 *  built-in Error.prototype in their prototype chain) and are also
 *  extensible.  User error handlers have no limitations in this respect.
 */

/* #include duk_internal.h -> already included */

/*
 *  Helper for calling a user error handler.
 *
 *  'thr' must be the currently active thread; the error handler is called
 *  in its context.  The valstack of 'thr' must have the error value on
 *  top, and will be replaced by another error value based on the return
 *  value of the error handler.
 *
 *  The helper calls duk_handle_call() recursively in protected mode.
 *  Before that call happens, no longjmps should happen; as a consequence,
 *  we must assume that the valstack contains enough temporary space for
 *  arguments and such.
 *
 *  While the error handler runs, any errors thrown will not trigger a
 *  recursive error handler call (this is implemented using a heap level
 *  flag which will "follow" through any coroutines resumed inside the
 *  error handler).  If the error handler is not callable or throws an
 *  error, the resulting error replaces the original error (for Duktape
 *  internal errors, duk_error_throw.c further substitutes this error with
 *  a DoubleError which is not ideal).  This would be easy to change and
 *  even signal to the caller.
 *
 *  The user error handler is stored in 'Duktape.errCreate' or
 *  'Duktape.errThrow' depending on whether we're augmenting the error at
 *  creation or throw time.  There are several alternatives to this approach,
 *  see doc/error-objects.rst for discussion.
 *
 *  Note: since further longjmp()s may occur while calling the error handler
 *  (for many reasons, e.g. a labeled 'break' inside the handler), the
 *  caller can make no assumptions on the thr->heap->lj state after the
 *  call (this affects especially duk_error_throw.c).  This is not an issue
 *  as long as the caller writes to the lj state only after the error handler
 *  finishes.
 */

#if defined(DUK_USE_ERRTHROW) || defined(DUK_USE_ERRCREATE)
DUK_LOCAL void duk__err_augment_user(duk_hthread *thr, duk_small_uint_t stridx_cb) {
	duk_tval *tv_hnd;
	duk_int_t rc;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT_STRIDX_VALID(stridx_cb);

	if (thr->heap->augmenting_error) {
		DUK_D(DUK_DPRINT("recursive call to error augmentation, ignore"));
		return;
	}

	/*
	 *  Check whether or not we have an error handler.
	 *
	 *  We must be careful of not triggering an error when looking up the
	 *  property.  For instance, if the property is a getter, we don't want
	 *  to call it, only plain values are allowed.  The value, if it exists,
	 *  is not checked.  If the value is not a function, a TypeError happens
	 *  when it is called and that error replaces the original one.
	 */

	DUK_ASSERT_VALSTACK_SPACE(thr, 4);  /* 3 entries actually needed below */

	/* [ ... errval ] */

	if (thr->builtins[DUK_BIDX_DUKTAPE] == NULL) {
		/* When creating built-ins, some of the built-ins may not be set
		 * and we want to tolerate that when throwing errors.
		 */
		DUK_DD(DUK_DDPRINT("error occurred when DUK_BIDX_DUKTAPE is NULL, ignoring"));
		return;
	}
	tv_hnd = duk_hobject_find_entry_tval_ptr_stridx(thr->heap,
	                                                thr->builtins[DUK_BIDX_DUKTAPE],
	                                                stridx_cb);
	if (tv_hnd == NULL) {
		DUK_DD(DUK_DDPRINT("error handler does not exist or is not a plain value: %!T",
		                   (duk_tval *) tv_hnd));
		return;
	}
	DUK_DDD(DUK_DDDPRINT("error handler dump (callability not checked): %!T",
	                     (duk_tval *) tv_hnd));
	duk_push_tval(thr, tv_hnd);

	/* [ ... errval errhandler ] */

	duk_insert(thr, -2);  /* -> [ ... errhandler errval ] */
	duk_push_undefined(thr);
	duk_insert(thr, -2);  /* -> [ ... errhandler undefined(= this) errval ] */

	/* [ ... errhandler undefined errval ] */

	/*
	 *  heap->augmenting_error prevents recursive re-entry and also causes
	 *  call handling to use a larger (but not unbounded) call stack limit
	 *  for the duration of error augmentation.
	 *
	 *  We ignore errors now: a success return and an error value both
	 *  replace the original error value.  (This would be easy to change.)
	 */

	DUK_ASSERT(thr->heap->augmenting_error == 0);
	thr->heap->augmenting_error = 1;

	rc = duk_pcall_method(thr, 1);
	DUK_UNREF(rc);  /* no need to check now: both success and error are OK */

	DUK_ASSERT(thr->heap->augmenting_error == 1);
	thr->heap->augmenting_error = 0;

	/* [ ... errval ] */
}
#endif  /* DUK_USE_ERRTHROW || DUK_USE_ERRCREATE */

/*
 *  Add ._Tracedata to an error on the stack top.
 */

#if defined(DUK_USE_TRACEBACKS)
DUK_LOCAL void duk__add_traceback(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
	duk_activation *act;
	duk_int_t depth;
	duk_int_t arr_size;
	duk_tval *tv;
	duk_hstring *s;
	duk_uint32_t u32;
	duk_double_t d;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr_callstack != NULL);

	/* [ ... error ] */

	/*
	 *  The traceback format is pretty arcane in an attempt to keep it compact
	 *  and cheap to create.  It may change arbitrarily from version to version.
	 *  It should be decoded/accessed through version specific accessors only.
	 *
	 *  See doc/error-objects.rst.
	 */

	DUK_DDD(DUK_DDDPRINT("adding traceback to object: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	/* Preallocate array to correct size, so that we can just write out
	 * the _Tracedata values into the array part.
	 */
	act = thr->callstack_curr;
	depth = DUK_USE_TRACEBACK_DEPTH;
	DUK_ASSERT(thr_callstack->callstack_top <= DUK_INT_MAX);  /* callstack limits */
	if (depth > (duk_int_t) thr_callstack->callstack_top) {
		depth = (duk_int_t) thr_callstack->callstack_top;
	}
	if (depth > 0) {
		if (flags & DUK_AUGMENT_FLAG_SKIP_ONE) {
			DUK_ASSERT(act != NULL);
			act = act->parent;
			depth--;
		}
	}
	arr_size = depth * 2;
	if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
		arr_size += 2;
	}
	if (c_filename) {
		/* We need the C filename to be interned before getting the
		 * array part pointer to avoid any GC interference while the
		 * array part is populated.
		 */
		duk_push_string(thr, c_filename);
		arr_size += 2;
	}

	/* XXX: Uninitialized would be OK.  Maybe add internal primitive to
	 * push bare duk_harray with size?
	 */
	DUK_D(DUK_DPRINT("preallocated _Tracedata to %ld items", (long) arr_size));
	tv = duk_push_harray_with_size_outptr(thr, (duk_uint32_t) arr_size);
	duk_clear_prototype(thr, -1);
	DUK_ASSERT(duk_is_bare_object(thr, -1));
	DUK_ASSERT(arr_size == 0 || tv != NULL);

	/* Compiler SyntaxErrors (and other errors) come first, and are
	 * blamed by default (not flagged "noblame").
	 */
	if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
		s = thr->compile_ctx->h_filename;
		DUK_TVAL_SET_STRING(tv, s);
		DUK_HSTRING_INCREF(thr, s);
		tv++;

		u32 = (duk_uint32_t) thr->compile_ctx->curr_token.start_line;  /* (flags<<32) + (line), flags = 0 */
		DUK_TVAL_SET_U32(tv, u32);
		tv++;
	}

	/* Filename/line from C macros (__FILE__, __LINE__) are added as an
	 * entry with a special format: (string, number).  The number contains
	 * the line and flags.
	 */

	/* [ ... error c_filename? arr ] */

	if (c_filename) {
		DUK_ASSERT(DUK_TVAL_IS_STRING(thr->valstack_top - 2));
		s = DUK_TVAL_GET_STRING(thr->valstack_top - 2);  /* interned c_filename */
		DUK_ASSERT(s != NULL);
		DUK_TVAL_SET_STRING(tv, s);
		DUK_HSTRING_INCREF(thr, s);
		tv++;

		d = ((flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE) ? ((duk_double_t) DUK_TB_FLAG_NOBLAME_FILELINE) * DUK_DOUBLE_2TO32 : 0.0) +
		    (duk_double_t) c_line;
		DUK_TVAL_SET_DOUBLE(tv, d);
		tv++;
	}

	/* Traceback depth doesn't take into account the filename/line
	 * special handling above (intentional).
	 */
	for (; depth-- > 0; act = act->parent) {
		duk_uint32_t pc;
		duk_tval *tv_src;

		/* [... arr] */

		DUK_ASSERT(act != NULL);  /* depth check above, assumes book-keeping is correct */
		DUK_ASSERT_DISABLE(act->pc >= 0);  /* unsigned */

		/* Add function object. */
		tv_src = &act->tv_func;  /* object (function) or lightfunc */
		DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv_src) || DUK_TVAL_IS_LIGHTFUNC(tv_src));
		DUK_TVAL_SET_TVAL(tv, tv_src);
		DUK_TVAL_INCREF(thr, tv);
		tv++;

		/* Add a number containing: pc, activation flags.
		 *
		 * PC points to next instruction, find offending PC.  Note that
		 * PC == 0 for native code.
		 */
		pc = (duk_uint32_t) duk_hthread_get_act_prev_pc(thr_callstack, act);
		DUK_ASSERT_DISABLE(pc >= 0);  /* unsigned */
		DUK_ASSERT((duk_double_t) pc < DUK_DOUBLE_2TO32);  /* assume PC is at most 32 bits and non-negative */
		d = ((duk_double_t) act->flags) * DUK_DOUBLE_2TO32 + (duk_double_t) pc;
		DUK_TVAL_SET_DOUBLE(tv, d);
		tv++;
	}

#if defined(DUK_USE_ASSERTIONS)
	{
		duk_harray *a;
		a = (duk_harray *) duk_known_hobject(thr, -1);
		DUK_ASSERT(a != NULL);
		DUK_ASSERT((duk_uint32_t) (tv - DUK_HOBJECT_A_GET_BASE(thr->heap, (duk_hobject *) a)) == a->length);
		DUK_ASSERT(a->length == (duk_uint32_t) arr_size);
		DUK_ASSERT(duk_is_bare_object(thr, -1));
	}
#endif

	/* [ ... error c_filename? arr ] */

	if (c_filename) {
		duk_remove_m2(thr);
	}

	/* [ ... error arr ] */

	duk_xdef_prop_stridx_short_wec(thr, -2, DUK_STRIDX_INT_TRACEDATA);  /* -> [ ... error ] */
}
#endif  /* DUK_USE_TRACEBACKS */

/*
 *  Add .fileName and .lineNumber to an error on the stack top.
 */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE) && !defined(DUK_USE_TRACEBACKS)
DUK_LOCAL void duk__add_fileline(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
#if defined(DUK_USE_ASSERTIONS)
	duk_int_t entry_top;
#endif

#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(thr);
#endif

	/*
	 *  If tracebacks are disabled, 'fileName' and 'lineNumber' are added
	 *  as plain own properties.  Since Error.prototype has accessors of
	 *  the same name, we need to define own properties directly (cannot
	 *  just use e.g. duk_put_prop_stridx).  Existing properties are not
	 *  overwritten in case they already exist.
	 */

	if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
		/* Compiler SyntaxError (or other error) gets the primary blame.
		 * Currently no flag to prevent blaming.
		 */
		duk_push_uint(thr, (duk_uint_t) thr->compile_ctx->curr_token.start_line);
		duk_push_hstring(thr, thr->compile_ctx->h_filename);
	} else if (c_filename && (flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE) == 0) {
		/* C call site gets blamed next, unless flagged not to do so.
		 * XXX: file/line is disabled in minimal builds, so disable this
		 * too when appropriate.
		 */
		duk_push_int(thr, c_line);
		duk_push_string(thr, c_filename);
	} else {
		/* Finally, blame the innermost callstack entry which has a
		 * .fileName property.
		 */
		duk_small_uint_t depth;
		duk_uint32_t ecma_line;
		duk_activation *act;

		DUK_ASSERT(thr_callstack->callstack_top <= DUK_INT_MAX);  /* callstack limits */
		depth = DUK_USE_TRACEBACK_DEPTH;
		if (depth > thr_callstack->callstack_top) {
			depth = thr_callstack->callstack_top;
		}
		for (act = thr_callstack->callstack_curr; depth-- > 0; act = act->parent) {
			duk_hobject *func;
			duk_uint32_t pc;

			DUK_ASSERT(act != NULL);
			func = DUK_ACT_GET_FUNC(act);
			if (func == NULL) {
				/* Lightfunc, not blamed now. */
				continue;
			}

			/* PC points to next instruction, find offending PC,
			 * PC == 0 for native code.
			 */
			pc = duk_hthread_get_act_prev_pc(thr, act);  /* thr argument only used for thr->heap, so specific thread doesn't matter */
			DUK_UNREF(pc);
			DUK_ASSERT_DISABLE(pc >= 0);  /* unsigned */
			DUK_ASSERT((duk_double_t) pc < DUK_DOUBLE_2TO32);  /* assume PC is at most 32 bits and non-negative */

			duk_push_hobject(thr, func);

			/* [ ... error func ] */

			duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_FILE_NAME);
			if (!duk_is_string_notsymbol(thr, -1)) {
				duk_pop_2(thr);
				continue;
			}

			/* [ ... error func fileName ] */

			ecma_line = 0;
#if defined(DUK_USE_PC2LINE)
			if (DUK_HOBJECT_IS_COMPFUNC(func)) {
				ecma_line = duk_hobject_pc2line_query(thr, -2, (duk_uint_fast32_t) pc);
			} else {
				/* Native function, no relevant lineNumber. */
			}
#endif  /* DUK_USE_PC2LINE */
			duk_push_u32(thr, ecma_line);

			/* [ ... error func fileName lineNumber ] */

			duk_replace(thr, -3);

			/* [ ... error lineNumber fileName ] */
			goto define_props;
		}

		/* No activation matches, use undefined for both .fileName and
		 * .lineNumber (matches what we do with a _Tracedata based
		 * no-match lookup.
		 */
		duk_push_undefined(thr);
		duk_push_undefined(thr);
	}

 define_props:
	/* [ ... error lineNumber fileName ] */
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(duk_get_top(thr) == entry_top + 2);
#endif
	duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_C | DUK_PROPDESC_FLAG_NO_OVERWRITE);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LINE_NUMBER, DUK_PROPDESC_FLAGS_C | DUK_PROPDESC_FLAG_NO_OVERWRITE);
}
#endif  /* DUK_USE_AUGMENT_ERROR_CREATE && !DUK_USE_TRACEBACKS */

/*
 *  Add line number to a compiler error.
 */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_LOCAL void duk__add_compiler_error_line(duk_hthread *thr) {

	/* Append a "(line NNN)" to the "message" property of any error
	 * thrown during compilation.  Usually compilation errors are
	 * SyntaxErrors but they can also be out-of-memory errors and
	 * the like.
	 */

	/* [ ... error ] */

	DUK_ASSERT(duk_is_object(thr, -1));

	if (!(thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL)) {
		return;
	}

	DUK_DDD(DUK_DDDPRINT("compile error, before adding line info: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	if (duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_MESSAGE)) {
		duk_bool_t at_end;

		/* Best guesstimate that error occurred at end of input, token
		 * truncated by end of input, etc.
		 */
#if 0
		at_end = (thr->compile_ctx->curr_token.start_offset + 1 >= thr->compile_ctx->lex.input_length);
		at_end = (thr->compile_ctx->lex.window[0].codepoint < 0 || thr->compile_ctx->lex.window[1].codepoint < 0);
#endif
		at_end = (thr->compile_ctx->lex.window[0].codepoint < 0);

		DUK_D(DUK_DPRINT("syntax error, determined at_end=%ld; curr_token.start_offset=%ld, "
		                 "lex.input_length=%ld, window[0].codepoint=%ld, window[1].codepoint=%ld",
		                 (long) at_end,
		                 (long) thr->compile_ctx->curr_token.start_offset,
		                 (long) thr->compile_ctx->lex.input_length,
		                 (long) thr->compile_ctx->lex.window[0].codepoint,
		                 (long) thr->compile_ctx->lex.window[1].codepoint));

		duk_push_sprintf(thr, " (line %ld%s)",
		                 (long) thr->compile_ctx->curr_token.start_line,
		                 at_end ? ", end of input" : "");
		duk_concat(thr, 2);
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE);
	} else {
		duk_pop(thr);
	}

	DUK_DDD(DUK_DDDPRINT("compile error, after adding line info: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));
}
#endif  /* DUK_USE_AUGMENT_ERROR_CREATE */

/*
 *  Augment an error being created using Duktape specific properties
 *  like _Tracedata or .fileName/.lineNumber.
 */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_LOCAL void duk__err_augment_builtin_create(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_hobject *obj, duk_small_uint_t flags) {
#if defined(DUK_USE_ASSERTIONS)
	duk_int_t entry_top;
#endif

#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(thr);
#endif
	DUK_ASSERT(obj != NULL);

	DUK_UNREF(obj);  /* unreferenced w/o tracebacks */

	duk__add_compiler_error_line(thr);

#if defined(DUK_USE_TRACEBACKS)
	/* If tracebacks are enabled, the '_Tracedata' property is the only
	 * thing we need: 'fileName' and 'lineNumber' are virtual properties
	 * which use '_Tracedata'.  (Check _Tracedata only as own property.)
	 */
	if (duk_hobject_find_entry_tval_ptr_stridx(thr->heap, obj, DUK_STRIDX_INT_TRACEDATA) != NULL) {
		DUK_DDD(DUK_DDDPRINT("error value already has a '_Tracedata' property, not modifying it"));
	} else {
		duk__add_traceback(thr, thr_callstack, c_filename, c_line, flags);
	}
#else
	/* Without tracebacks the concrete .fileName and .lineNumber need
	 * to be added directly.
	 */
	duk__add_fileline(thr, thr_callstack, c_filename, c_line, flags);
#endif

#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(duk_get_top(thr) == entry_top);
#endif
}
#endif  /* DUK_USE_AUGMENT_ERROR_CREATE */

/*
 *  Augment an error at creation time with _Tracedata/fileName/lineNumber
 *  and allow a user error handler (if defined) to process/replace the error.
 *  The error to be augmented is at the stack top.
 *
 *  thr: thread containing the error value
 *  thr_callstack: thread which should be used for generating callstack etc.
 *  c_filename: C __FILE__ related to the error
 *  c_line: C __LINE__ related to the error
 *  flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE:
 *      if true, don't fileName/line as error source, otherwise use traceback
 *      (needed because user code filename/line are reported but internal ones
 *      are not)
 */

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_INTERNAL void duk_err_augment_error_create(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
	duk_hobject *obj;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr_callstack != NULL);

	/* [ ... error ] */

	/*
	 *  Criteria for augmenting:
	 *
	 *   - augmentation enabled in build (naturally)
	 *   - error value internal prototype chain contains the built-in
	 *     Error prototype object (i.e. 'val instanceof Error')
	 *
	 *  Additional criteria for built-in augmenting:
	 *
	 *   - error value is an extensible object
	 */

	obj = duk_get_hobject(thr, -1);
	if (!obj) {
		DUK_DDD(DUK_DDDPRINT("value is not an object, skip both built-in and user augment"));
		return;
	}
	if (!duk_hobject_prototype_chain_contains(thr, obj, thr->builtins[DUK_BIDX_ERROR_PROTOTYPE], 1 /*ignore_loop*/)) {
		/* If the value has a prototype loop, it's critical not to
		 * throw here.  Instead, assume the value is not to be
		 * augmented.
		 */
		DUK_DDD(DUK_DDDPRINT("value is not an error instance, skip both built-in and user augment"));
		return;
	}
	if (DUK_HOBJECT_HAS_EXTENSIBLE(obj)) {
		DUK_DDD(DUK_DDDPRINT("error meets criteria, built-in augment"));
		duk__err_augment_builtin_create(thr, thr_callstack, c_filename, c_line, obj, flags);
	} else {
		DUK_DDD(DUK_DDDPRINT("error does not meet criteria, no built-in augment"));
	}

	/* [ ... error ] */

#if defined(DUK_USE_ERRCREATE)
	duk__err_augment_user(thr, DUK_STRIDX_ERR_CREATE);
#endif
}
#endif  /* DUK_USE_AUGMENT_ERROR_CREATE */

/*
 *  Augment an error at throw time; allow a user error handler (if defined)
 *  to process/replace the error.  The error to be augmented is at the
 *  stack top.
 */

#if defined(DUK_USE_AUGMENT_ERROR_THROW)
DUK_INTERNAL void duk_err_augment_error_throw(duk_hthread *thr) {
#if defined(DUK_USE_ERRTHROW)
	duk__err_augment_user(thr, DUK_STRIDX_ERR_THROW);
#endif  /* DUK_USE_ERRTHROW */
}
#endif  /* DUK_USE_AUGMENT_ERROR_THROW */
/*
 *  Do a longjmp call, calling the fatal error handler if no
 *  catchpoint exists.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_PREFER_SIZE)
DUK_NORETURN(DUK_LOCAL_DECL void duk__uncaught_minimal(duk_hthread *thr));
DUK_LOCAL void duk__uncaught_minimal(duk_hthread *thr) {
	(void) duk_fatal(thr, "uncaught error");
	DUK_WO_NORETURN(return;);
}
#endif

#if 0
DUK_NORETURN(DUK_LOCAL_DECL void duk__uncaught_readable(duk_hthread *thr));
DUK_LOCAL void duk__uncaught_readable(duk_hthread *thr) {
	const char *summary;
	char buf[DUK_USE_FATAL_MAXLEN];

	summary = duk_push_string_tval_readable(thr, &thr->heap->lj.value1);
	DUK_SNPRINTF(buf, sizeof(buf), "uncaught: %s", summary);
	buf[sizeof(buf) - 1] = (char) 0;
	(void) duk_fatal(thr, (const char *) buf);
	DUK_WO_NORETURN(return;);
}
#endif

#if !defined(DUK_USE_PREFER_SIZE)
DUK_NORETURN(DUK_LOCAL_DECL void duk__uncaught_error_aware(duk_hthread *thr));
DUK_LOCAL void duk__uncaught_error_aware(duk_hthread *thr) {
	const char *summary;
	char buf[DUK_USE_FATAL_MAXLEN];

	summary = duk_push_string_tval_readable_error(thr, &thr->heap->lj.value1);
	DUK_ASSERT(summary != NULL);
	DUK_SNPRINTF(buf, sizeof(buf), "uncaught: %s", summary);
	buf[sizeof(buf) - 1] = (char) 0;
	(void) duk_fatal(thr, (const char *) buf);
	DUK_WO_NORETURN(return;);
}
#endif

DUK_INTERNAL void duk_err_longjmp(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

	DUK_DD(DUK_DDPRINT("longjmp error: type=%d iserror=%d value1=%!T value2=%!T",
	                   (int) thr->heap->lj.type, (int) thr->heap->lj.iserror,
	                   &thr->heap->lj.value1, &thr->heap->lj.value2));

	/* Prevent finalizer execution during error handling.  All error
	 * handling sites will process pending finalizers once error handling
	 * is complete and we're ready for the side effects.  Does not prevent
	 * refzero freeing or mark-and-sweep during error handling.
	 *
	 * NOTE: when we come here some calling code may have used DECREF
	 * NORZ macros without an explicit DUK_REFZERO_CHECK_xxx() call.
	 * We don't want to do it here because it would just check for
	 * pending finalizers and we prevent that explicitly.  Instead,
	 * the error catcher will run the finalizers once error handling
	 * is complete.
	 */

	DUK_ASSERT_LJSTATE_SET(thr->heap);

	thr->heap->pf_prevent_count++;
	DUK_ASSERT(thr->heap->pf_prevent_count != 0);  /* Wrap. */

#if defined(DUK_USE_ASSERTIONS)
	/* XXX: set this immediately when longjmp state is set */
	DUK_ASSERT(thr->heap->error_not_allowed == 0);  /* Detect error within critical section. */
	thr->heap->error_not_allowed = 1;
#endif

	DUK_DD(DUK_DDPRINT("about to longjmp, pf_prevent_count=%ld", (long) thr->heap->pf_prevent_count));

	/* If we don't have a jmpbuf_ptr, there is little we can do except
	 * cause a fatal error.  The caller's expectation is that we never
	 * return.
	 */
	if (!thr->heap->lj.jmpbuf_ptr) {
		DUK_D(DUK_DPRINT("uncaught error: type=%d iserror=%d value1=%!T value2=%!T",
		                 (int) thr->heap->lj.type, (int) thr->heap->lj.iserror,
		                 &thr->heap->lj.value1, &thr->heap->lj.value2));

#if defined(DUK_USE_PREFER_SIZE)
		duk__uncaught_minimal(thr);
#else
		duk__uncaught_error_aware(thr);
#endif
		DUK_UNREACHABLE();
	}

#if defined(DUK_USE_CPP_EXCEPTIONS)
	throw duk_internal_exception();  /* dummy */
#else
	DUK_LONGJMP(thr->heap->lj.jmpbuf_ptr->jb);
#endif

	DUK_UNREACHABLE();
}
/*
 *  Error helpers
 */

/* #include duk_internal.h -> already included */

/*
 *  Helper to walk the thread chain and see if there is an active error
 *  catcher.  Protected calls or finally blocks aren't considered catching.
 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_LOCAL duk_bool_t duk__have_active_catcher(duk_hthread *thr) {
	/* As noted above, a protected API call won't be counted as a
	 * catcher.  This is usually convenient, e.g. in the case of a top-
	 * level duk_pcall(), but may not always be desirable.  Perhaps add
	 * an argument to treat them as catchers?
	 */

	duk_activation *act;
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);

	for (; thr != NULL; thr = thr->resumer) {
		for (act = thr->callstack_curr; act != NULL; act = act->parent) {
			for (cat = act->cat; cat != NULL; cat = cat->parent) {
				if (DUK_CAT_HAS_CATCH_ENABLED(cat)) {
					return 1;  /* all we need to know */
				}
			}
		}
	}
	return 0;
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

/*
 *  Get prototype object for an integer error code.
 */

DUK_INTERNAL duk_hobject *duk_error_prototype_from_code(duk_hthread *thr, duk_errcode_t code) {
	switch (code) {
	case DUK_ERR_EVAL_ERROR:
		return thr->builtins[DUK_BIDX_EVAL_ERROR_PROTOTYPE];
	case DUK_ERR_RANGE_ERROR:
		return thr->builtins[DUK_BIDX_RANGE_ERROR_PROTOTYPE];
	case DUK_ERR_REFERENCE_ERROR:
		return thr->builtins[DUK_BIDX_REFERENCE_ERROR_PROTOTYPE];
	case DUK_ERR_SYNTAX_ERROR:
		return thr->builtins[DUK_BIDX_SYNTAX_ERROR_PROTOTYPE];
	case DUK_ERR_TYPE_ERROR:
		return thr->builtins[DUK_BIDX_TYPE_ERROR_PROTOTYPE];
	case DUK_ERR_URI_ERROR:
		return thr->builtins[DUK_BIDX_URI_ERROR_PROTOTYPE];
	case DUK_ERR_ERROR:
	default:
		return thr->builtins[DUK_BIDX_ERROR_PROTOTYPE];
	}
}

/*
 *  Helper for debugger throw notify and pause-on-uncaught integration.
 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL void duk_err_check_debugger_integration(duk_hthread *thr) {
	duk_bool_t uncaught;
	duk_tval *tv_obj;

	/* If something is thrown with the debugger attached and nobody will
	 * catch it, execution is paused before the longjmp, turning over
	 * control to the debug client.  This allows local state to be examined
	 * before the stack is unwound.  Errors are not intercepted when debug
	 * message loop is active (e.g. for Eval).
	 */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

	/* XXX: Allow customizing the pause and notify behavior at runtime
	 * using debugger runtime flags.  For now the behavior is fixed using
	 * config options.
	 */

	if (!duk_debug_is_attached(thr->heap) ||
	    thr->heap->dbg_processing ||
	    thr->heap->lj.type != DUK_LJ_TYPE_THROW ||
	    thr->heap->creating_error) {
		DUK_D(DUK_DPRINT("skip debugger error integration; not attached, debugger processing, not THROW, or error thrown while creating error"));
		return;
	}

	/* Don't intercept a DoubleError, we may have caused the initial double
	 * fault and attempting to intercept it will cause us to be called
	 * recursively and exhaust the C stack.  (This should no longer happen
	 * for the initial throw because DoubleError path doesn't do a debugger
	 * integration check, but it might happen for rethrows.)
	 */
	tv_obj = &thr->heap->lj.value1;
	if (DUK_TVAL_IS_OBJECT(tv_obj) && DUK_TVAL_GET_OBJECT(tv_obj) == thr->builtins[DUK_BIDX_DOUBLE_ERROR]) {
		DUK_D(DUK_DPRINT("built-in DoubleError instance (re)thrown, not intercepting"));
		return;
	}

	uncaught = !duk__have_active_catcher(thr);

	/* Debugger code expects the value at stack top.  This also serves
	 * as a backup: we need to store/restore the longjmp state because
	 * when the debugger is paused Eval commands may be executed and
	 * they can arbitrarily clobber the longjmp state.
	 */
	duk_push_tval(thr, tv_obj);

	/* Store and reset longjmp state. */
	DUK_ASSERT_LJSTATE_SET(thr->heap);
	DUK_TVAL_DECREF_NORZ(thr, tv_obj);
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));  /* Always for THROW type. */
	DUK_TVAL_SET_UNDEFINED(tv_obj);
	thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
	DUK_ASSERT_LJSTATE_UNSET(thr->heap);

#if defined(DUK_USE_DEBUGGER_THROW_NOTIFY)
	/* Report it to the debug client */
	DUK_D(DUK_DPRINT("throw with debugger attached, report to client"));
	duk_debug_send_throw(thr, uncaught);
#endif

	if (uncaught) {
		if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_UNCAUGHT_ERROR) {
			DUK_D(DUK_DPRINT("PAUSE TRIGGERED by uncaught error"));
			duk_debug_halt_execution(thr, 1 /*use_prev_pc*/);
		}
	} else {
		if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_CAUGHT_ERROR) {
			DUK_D(DUK_DPRINT("PAUSE TRIGGERED by caught error"));
			duk_debug_halt_execution(thr, 1 /*use_prev_pc*/);
		}
	}

	/* Restore longjmp state. */
	DUK_ASSERT_LJSTATE_UNSET(thr->heap);
	thr->heap->lj.type = DUK_LJ_TYPE_THROW;
	tv_obj = DUK_GET_TVAL_NEGIDX(thr, -1);
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value1));
	DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));
	DUK_TVAL_SET_TVAL(&thr->heap->lj.value1, tv_obj);
	DUK_TVAL_INCREF(thr, tv_obj);
	DUK_ASSERT_LJSTATE_SET(thr->heap);

	duk_pop(thr);
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

/*
 *  Helpers for setting up heap longjmp state.
 */

DUK_INTERNAL void duk_err_setup_ljstate1(duk_hthread *thr, duk_small_uint_t lj_type, duk_tval *tv_val) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	heap = thr->heap;
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(tv_val != NULL);

	DUK_ASSERT_LJSTATE_UNSET(heap);

	heap->lj.type = lj_type;
	DUK_TVAL_SET_TVAL(&heap->lj.value1, tv_val);
	DUK_TVAL_INCREF(thr, tv_val);

	DUK_ASSERT_LJSTATE_SET(heap);
}
/*
 *  Create and throw an ECMAScript error object based on a code and a message.
 *
 *  Used when we throw errors internally.  ECMAScript generated error objects
 *  are created by ECMAScript code, and the throwing is handled by the bytecode
 *  executor.
 */

/* #include duk_internal.h -> already included */

/*
 *  Create and throw an error (originating from Duktape internally)
 *
 *  Push an error object on top of the stack, possibly throw augmenting
 *  the error, and finally longjmp.
 *
 *  If an error occurs while we're dealing with the current error, we might
 *  enter an infinite recursion loop.  This is prevented by detecting a
 *  "double fault" through the heap->creating_error flag; the recursion
 *  then stops at the second level.
 */

#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_INTERNAL void duk_err_create_and_throw(duk_hthread *thr, duk_errcode_t code, const char *msg, const char *filename, duk_int_t line) {
#else
DUK_INTERNAL void duk_err_create_and_throw(duk_hthread *thr, duk_errcode_t code) {
#endif
#if defined(DUK_USE_VERBOSE_ERRORS)
	DUK_DD(DUK_DDPRINT("duk_err_create_and_throw(): code=%ld, msg=%s, filename=%s, line=%ld",
	                   (long) code, (const char *) msg,
	                   (const char *) filename, (long) line));
#else
	DUK_DD(DUK_DDPRINT("duk_err_create_and_throw(): code=%ld", (long) code));
#endif

	DUK_ASSERT(thr != NULL);

	/* Even though nested call is possible because we throw an error when
	 * trying to create an error, the potential errors must happen before
	 * the longjmp state is configured.
	 */
	DUK_ASSERT_LJSTATE_UNSET(thr->heap);

	/* Sync so that augmentation sees up-to-date activations, NULL
	 * thr->ptr_curr_pc so that it's not used if side effects occur
	 * in augmentation or longjmp handling.
	 */
	duk_hthread_sync_and_null_currpc(thr);

	/*
	 *  Create and push an error object onto the top of stack.
	 *  The error is potentially augmented before throwing.
	 *
	 *  If a "double error" occurs, use a fixed error instance
	 *  to avoid further trouble.
	 */

	if (thr->heap->creating_error) {
		duk_tval tv_val;
		duk_hobject *h_err;

		thr->heap->creating_error = 0;

		h_err = thr->builtins[DUK_BIDX_DOUBLE_ERROR];
		if (h_err != NULL) {
			DUK_D(DUK_DPRINT("double fault detected -> use built-in fixed 'double error' instance"));
			DUK_TVAL_SET_OBJECT(&tv_val, h_err);
		} else {
			DUK_D(DUK_DPRINT("double fault detected; there is no built-in fixed 'double error' instance "
			                 "-> use the error code as a number"));
			DUK_TVAL_SET_I32(&tv_val, (duk_int32_t) code);
		}

		duk_err_setup_ljstate1(thr, DUK_LJ_TYPE_THROW, &tv_val);

		/* No augmentation to avoid any allocations or side effects. */
	} else {
		/* Prevent infinite recursion.  Extra call stack and C
		 * recursion headroom (see GH-191) is added for augmentation.
		 * That is now signalled by heap->augmenting error and taken
		 * into account in call handling without an explicit limit bump.
		 */
		thr->heap->creating_error = 1;

		duk_require_stack(thr, 1);

		/* XXX: usually unnecessary '%s' formatting here, but cannot
		 * use 'msg' as a format string directly.
		 */
#if defined(DUK_USE_VERBOSE_ERRORS)
		duk_push_error_object_raw(thr,
		                          code | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
		                          filename,
		                          line,
		                          "%s",
		                          (const char *) msg);
#else
		duk_push_error_object_raw(thr,
		                          code | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
		                          NULL,
		                          0,
		                          NULL);
#endif

		/* Note that an alloc error may happen during error augmentation.
		 * This may happen both when the original error is an alloc error
		 * and when it's something else.  Because any error in augmentation
		 * must be handled correctly anyway, there's no special check for
		 * avoiding it for alloc errors (this differs from Duktape 1.x).
		 */
#if defined(DUK_USE_AUGMENT_ERROR_THROW)
		DUK_DDD(DUK_DDDPRINT("THROW ERROR (INTERNAL): %!iT (before throw augment)",
		                     (duk_tval *) duk_get_tval(thr, -1)));
		duk_err_augment_error_throw(thr);
#endif

		duk_err_setup_ljstate1(thr, DUK_LJ_TYPE_THROW, DUK_GET_TVAL_NEGIDX(thr, -1));
		thr->heap->creating_error = 0;

		/* Error is now created and we assume no errors can occur any
		 * more.  Check for debugger Throw integration only when the
		 * error is complete.  If we enter debugger message loop,
		 * creating_error must be 0 so that errors can be thrown in
		 * the paused state, e.g. in Eval commands.
		 */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
		duk_err_check_debugger_integration(thr);
#endif
	}

	/*
	 *  Finally, longjmp
	 */

	DUK_DDD(DUK_DDDPRINT("THROW ERROR (INTERNAL): %!iT, %!iT (after throw augment)",
	                     (duk_tval *) &thr->heap->lj.value1, (duk_tval *) &thr->heap->lj.value2));

	duk_err_longjmp(thr);
	DUK_UNREACHABLE();
}

/*
 *  Helper for C function call negative return values.
 */

DUK_INTERNAL void duk_error_throw_from_negative_rc(duk_hthread *thr, duk_ret_t rc) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(rc < 0);

	/*
	 *  The __FILE__ and __LINE__ information is intentionally not used in the
	 *  creation of the error object, as it isn't useful in the tracedata.  The
	 *  tracedata still contains the function which returned the negative return
	 *  code, and having the file/line of this function isn't very useful.
	 *
	 *  The error messages for DUK_RET_xxx shorthand are intentionally very
	 *  minimal: they're only really useful for low memory targets.
	 */

	duk_error_raw(thr, -rc, NULL, 0, "error (rc %ld)", (long) rc);
	DUK_WO_NORETURN(return;);
}
/*
 *  duk_hbuffer allocation and freeing.
 */

/* #include duk_internal.h -> already included */

/* Allocate a new duk_hbuffer of a certain type and return a pointer to it
 * (NULL on error).  Write buffer data pointer to 'out_bufdata' (only if
 * allocation successful).
 */
DUK_INTERNAL duk_hbuffer *duk_hbuffer_alloc(duk_heap *heap, duk_size_t size, duk_small_uint_t flags, void **out_bufdata) {
	duk_hbuffer *res = NULL;
	duk_size_t header_size;
	duk_size_t alloc_size;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(out_bufdata != NULL);

	DUK_DDD(DUK_DDDPRINT("allocate hbuffer"));

	/* Size sanity check.  Should not be necessary because caller is
	 * required to check this, but we don't want to cause a segfault
	 * if the size wraps either in duk_size_t computation or when
	 * storing the size in a 16-bit field.
	 */
	if (size > DUK_HBUFFER_MAX_BYTELEN) {
		DUK_D(DUK_DPRINT("hbuffer alloc failed: size too large: %ld", (long) size));
		return NULL;  /* no need to write 'out_bufdata' */
	}

	if (flags & DUK_BUF_FLAG_EXTERNAL) {
		header_size = sizeof(duk_hbuffer_external);
		alloc_size = sizeof(duk_hbuffer_external);
	} else if (flags & DUK_BUF_FLAG_DYNAMIC) {
		header_size = sizeof(duk_hbuffer_dynamic);
		alloc_size = sizeof(duk_hbuffer_dynamic);
	} else {
		header_size = sizeof(duk_hbuffer_fixed);
		alloc_size = sizeof(duk_hbuffer_fixed) + size;
		DUK_ASSERT(alloc_size >= sizeof(duk_hbuffer_fixed));  /* no wrapping */
	}

	res = (duk_hbuffer *) DUK_ALLOC(heap, alloc_size);
	if (DUK_UNLIKELY(res == NULL)) {
		goto alloc_error;
	}

	/* zero everything unless requested not to do so */
#if defined(DUK_USE_ZERO_BUFFER_DATA)
	duk_memzero((void *) res,
	            (flags & DUK_BUF_FLAG_NOZERO) ? header_size : alloc_size);
#else
	duk_memzero((void *) res, header_size);
#endif

	if (flags & DUK_BUF_FLAG_EXTERNAL) {
		duk_hbuffer_external *h;
		h = (duk_hbuffer_external *) res;
		DUK_UNREF(h);
		*out_bufdata = NULL;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
#if defined(DUK_USE_HEAPPTR16)
/* the compressed pointer is zeroed which maps to NULL, so nothing to do. */
#else
		DUK_HBUFFER_EXTERNAL_SET_DATA_PTR(heap, h, NULL);
#endif
#endif
		DUK_ASSERT(DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(heap, h) == NULL);
	} else if (flags & DUK_BUF_FLAG_DYNAMIC) {
		duk_hbuffer_dynamic *h = (duk_hbuffer_dynamic *) res;
		void *ptr;

		if (size > 0) {
			DUK_ASSERT(!(flags & DUK_BUF_FLAG_EXTERNAL));  /* alloc external with size zero */
			DUK_DDD(DUK_DDDPRINT("dynamic buffer with nonzero size, alloc actual buffer"));
#if defined(DUK_USE_ZERO_BUFFER_DATA)
			ptr = DUK_ALLOC_ZEROED(heap, size);
#else
			ptr = DUK_ALLOC(heap, size);
#endif
			if (DUK_UNLIKELY(ptr == NULL)) {
				/* Because size > 0, NULL check is correct */
				goto alloc_error;
			}
			*out_bufdata = ptr;

			DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap, h, ptr);
		} else {
			*out_bufdata = NULL;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
#if defined(DUK_USE_HEAPPTR16)
/* the compressed pointer is zeroed which maps to NULL, so nothing to do. */
#else
			DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap, h, NULL);
#endif
#endif
			DUK_ASSERT(DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, h) == NULL);
		}
	} else {
		*out_bufdata = (void *) ((duk_hbuffer_fixed *) (void *) res + 1);
	}

	DUK_HBUFFER_SET_SIZE(res, size);

	DUK_HEAPHDR_SET_TYPE(&res->hdr, DUK_HTYPE_BUFFER);
	if (flags & DUK_BUF_FLAG_DYNAMIC) {
		DUK_HBUFFER_SET_DYNAMIC(res);
		if (flags & DUK_BUF_FLAG_EXTERNAL) {
			DUK_HBUFFER_SET_EXTERNAL(res);
		}
	} else {
		DUK_ASSERT(!(flags & DUK_BUF_FLAG_EXTERNAL));
	}
        DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, &res->hdr);

	DUK_DDD(DUK_DDDPRINT("allocated hbuffer: %p", (void *) res));
	return res;

 alloc_error:
	DUK_DD(DUK_DDPRINT("hbuffer allocation failed"));

	DUK_FREE(heap, res);
	return NULL;  /* no need to write 'out_bufdata' */
}

/* For indirect allocs. */

DUK_INTERNAL void *duk_hbuffer_get_dynalloc_ptr(duk_heap *heap, void *ud) {
	duk_hbuffer_dynamic *buf = (duk_hbuffer_dynamic *) ud;
	DUK_UNREF(heap);
	return (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, buf);
}
/*
 *  duk_hbuffer assertion helpers
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ASSERTIONS)

DUK_INTERNAL void duk_hbuffer_assert_valid(duk_hbuffer *h) {
	DUK_ASSERT(h != NULL);
}

#endif  /* DUK_USE_ASSERTIONS */
/*
 *  duk_hbuffer operations such as resizing and inserting/appending data to
 *  a dynamic buffer.
 */

/* #include duk_internal.h -> already included */

/*
 *  Resizing
 */

DUK_INTERNAL void duk_hbuffer_resize(duk_hthread *thr, duk_hbuffer_dynamic *buf, duk_size_t new_size) {
	void *res;
	duk_size_t prev_size;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(buf));
	DUK_ASSERT(!DUK_HBUFFER_HAS_EXTERNAL(buf));

	/*
	 *  Maximum size check
	 */

	if (new_size > DUK_HBUFFER_MAX_BYTELEN) {
		DUK_ERROR_RANGE(thr, "buffer too long");
		DUK_WO_NORETURN(return;);
	}

	/*
	 *  Note: use indirect realloc variant just in case mark-and-sweep
	 *  (finalizers) might resize this same buffer during garbage
	 *  collection.
	 */

	res = DUK_REALLOC_INDIRECT(thr->heap, duk_hbuffer_get_dynalloc_ptr, (void *) buf, new_size);
	if (DUK_LIKELY(res != NULL || new_size == 0)) {
		/* 'res' may be NULL if new allocation size is 0. */

		DUK_DDD(DUK_DDDPRINT("resized dynamic buffer %p:%ld -> %p:%ld",
		                     (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, buf),
		                     (long) DUK_HBUFFER_DYNAMIC_GET_SIZE(buf),
		                     (void *) res,
		                     (long) new_size));

		/*
		 *  The entire allocated buffer area, regardless of actual used
		 *  size, is kept zeroed in resizes for simplicity.  If the buffer
		 *  is grown, zero the new part.
		 */

		prev_size = DUK_HBUFFER_DYNAMIC_GET_SIZE(buf);
		if (new_size > prev_size) {
			DUK_ASSERT(new_size - prev_size > 0);
#if defined(DUK_USE_ZERO_BUFFER_DATA)
			duk_memzero((void *) ((char *) res + prev_size),
			            (duk_size_t) (new_size - prev_size));
#endif
		}

		DUK_HBUFFER_DYNAMIC_SET_SIZE(buf, new_size);
		DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(thr->heap, buf, res);
	} else {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return;);
	}

	DUK_ASSERT(res != NULL || new_size == 0);
}

DUK_INTERNAL void duk_hbuffer_reset(duk_hthread *thr, duk_hbuffer_dynamic *buf) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(buf));
	DUK_ASSERT(!DUK_HBUFFER_HAS_EXTERNAL(buf));

	duk_hbuffer_resize(thr, buf, 0);
}
/* #include duk_internal.h -> already included */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_uint_t duk_hbufobj_clamp_bytelength(duk_hbufobj *h_bufobj, duk_uint_t len) {
	duk_uint_t buf_size;
	duk_uint_t buf_avail;

	DUK_ASSERT(h_bufobj != NULL);
	DUK_ASSERT(h_bufobj->buf != NULL);

	buf_size = (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_bufobj->buf);
	if (h_bufobj->offset > buf_size) {
		/* Slice starting point is beyond current length. */
		return 0;
	}
	buf_avail = buf_size - h_bufobj->offset;

	return buf_avail >= len ? len : buf_avail;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
/*
 *  duk_heap allocation and freeing.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ROM_STRINGS)
/* Fixed seed value used with ROM strings. */
#define DUK__FIXED_HASH_SEED       0xabcd1234
#endif

/*
 *  Free a heap object.
 *
 *  Free heap object and its internal (non-heap) pointers.  Assumes that
 *  caller has removed the object from heap allocated list or the string
 *  intern table, and any weak references (which strings may have) have
 *  been already dealt with.
 */

DUK_INTERNAL void duk_free_hobject(duk_heap *heap, duk_hobject *h) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

	DUK_FREE(heap, DUK_HOBJECT_GET_PROPS(heap, h));

	if (DUK_HOBJECT_IS_COMPFUNC(h)) {
		duk_hcompfunc *f = (duk_hcompfunc *) h;
		DUK_UNREF(f);
		/* Currently nothing to free; 'data' is a heap object */
	} else if (DUK_HOBJECT_IS_NATFUNC(h)) {
		duk_hnatfunc *f = (duk_hnatfunc *) h;
		DUK_UNREF(f);
		/* Currently nothing to free */
	} else if (DUK_HOBJECT_IS_THREAD(h)) {
		duk_hthread *t = (duk_hthread *) h;
		duk_activation *act;

		DUK_FREE(heap, t->valstack);

		/* Don't free h->resumer because it exists in the heap.
		 * Callstack entries also contain function pointers which
		 * are not freed for the same reason.  They are decref
		 * finalized and the targets are freed if necessary based
		 * on their refcount (or reachability).
		 */
		for (act = t->callstack_curr; act != NULL;) {
			duk_activation *act_next;
			duk_catcher *cat;

			for (cat = act->cat; cat != NULL;) {
				duk_catcher *cat_next;

				cat_next = cat->parent;
				DUK_FREE(heap, (void *) cat);
				cat = cat_next;
			}

			act_next = act->parent;
			DUK_FREE(heap, (void *) act);
			act = act_next;
		}

		/* XXX: with 'caller' property the callstack would need
		 * to be unwound to update the 'caller' properties of
		 * functions in the callstack.
		 */
	} else if (DUK_HOBJECT_IS_BOUNDFUNC(h)) {
		duk_hboundfunc *f = (duk_hboundfunc *) (void *) h;

		DUK_FREE(heap, f->args);
	}

	DUK_FREE(heap, (void *) h);
}

DUK_INTERNAL void duk_free_hbuffer(duk_heap *heap, duk_hbuffer *h) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

	if (DUK_HBUFFER_HAS_DYNAMIC(h) && !DUK_HBUFFER_HAS_EXTERNAL(h)) {
		duk_hbuffer_dynamic *g = (duk_hbuffer_dynamic *) h;
		DUK_DDD(DUK_DDDPRINT("free dynamic buffer %p", (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, g)));
		DUK_FREE(heap, DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, g));
	}
	DUK_FREE(heap, (void *) h);
}

DUK_INTERNAL void duk_free_hstring(duk_heap *heap, duk_hstring *h) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

	DUK_UNREF(heap);
	DUK_UNREF(h);

#if defined(DUK_USE_HSTRING_EXTDATA) && defined(DUK_USE_EXTSTR_FREE)
	if (DUK_HSTRING_HAS_EXTDATA(h)) {
		DUK_DDD(DUK_DDDPRINT("free extstr: hstring %!O, extdata: %p",
		                     h, DUK_HSTRING_GET_EXTDATA((duk_hstring_external *) h)));
		DUK_USE_EXTSTR_FREE(heap->heap_udata, (const void *) DUK_HSTRING_GET_EXTDATA((duk_hstring_external *) h));
	}
#endif
	DUK_FREE(heap, (void *) h);
}

DUK_INTERNAL void duk_heap_free_heaphdr_raw(duk_heap *heap, duk_heaphdr *hdr) {
	DUK_ASSERT(heap);
	DUK_ASSERT(hdr);

	DUK_DDD(DUK_DDDPRINT("free heaphdr %p, htype %ld", (void *) hdr, (long) DUK_HEAPHDR_GET_TYPE(hdr)));

	switch (DUK_HEAPHDR_GET_TYPE(hdr)) {
	case DUK_HTYPE_STRING:
		duk_free_hstring(heap, (duk_hstring *) hdr);
		break;
	case DUK_HTYPE_OBJECT:
		duk_free_hobject(heap, (duk_hobject *) hdr);
		break;
	default:
		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(hdr) == DUK_HTYPE_BUFFER);
		duk_free_hbuffer(heap, (duk_hbuffer *) hdr);
	}

}

/*
 *  Free the heap.
 *
 *  Frees heap-related non-heap-tracked allocations such as the
 *  string intern table; then frees the heap allocated objects;
 *  and finally frees the heap structure itself.  Reference counts
 *  and GC markers are ignored (and not updated) in this process,
 *  and finalizers won't be called.
 *
 *  The heap pointer and heap object pointers must not be used
 *  after this call.
 */

#if defined(DUK_USE_CACHE_ACTIVATION)
DUK_LOCAL duk_size_t duk__heap_free_activation_freelist(duk_heap *heap) {
	duk_activation *act;
	duk_activation *act_next;
	duk_size_t count_act = 0;

	for (act = heap->activation_free; act != NULL;) {
		act_next = act->parent;
		DUK_FREE(heap, (void *) act);
		act = act_next;
#if defined(DUK_USE_DEBUG)
		count_act++;
#endif
	}
	heap->activation_free = NULL;  /* needed when called from mark-and-sweep */
	return count_act;
}
#endif  /* DUK_USE_CACHE_ACTIVATION */

#if defined(DUK_USE_CACHE_CATCHER)
DUK_LOCAL duk_size_t duk__heap_free_catcher_freelist(duk_heap *heap) {
	duk_catcher *cat;
	duk_catcher *cat_next;
	duk_size_t count_cat = 0;

	for (cat = heap->catcher_free; cat != NULL;) {
		cat_next = cat->parent;
		DUK_FREE(heap, (void *) cat);
		cat = cat_next;
#if defined(DUK_USE_DEBUG)
		count_cat++;
#endif
	}
	heap->catcher_free = NULL;  /* needed when called from mark-and-sweep */

	return count_cat;
}
#endif  /* DUK_USE_CACHE_CATCHER */

DUK_INTERNAL void duk_heap_free_freelists(duk_heap *heap) {
	duk_size_t count_act = 0;
	duk_size_t count_cat = 0;

#if defined(DUK_USE_CACHE_ACTIVATION)
	count_act = duk__heap_free_activation_freelist(heap);
#endif
#if defined(DUK_USE_CACHE_CATCHER)
	count_cat = duk__heap_free_catcher_freelist(heap);
#endif
	DUK_UNREF(heap);
	DUK_UNREF(count_act);
	DUK_UNREF(count_cat);

	DUK_D(DUK_DPRINT("freed %ld activation freelist entries, %ld catcher freelist entries",
	                 (long) count_act, (long) count_cat));
}

DUK_LOCAL void duk__free_allocated(duk_heap *heap) {
	duk_heaphdr *curr;
	duk_heaphdr *next;

	curr = heap->heap_allocated;
	while (curr) {
		/* We don't log or warn about freeing zero refcount objects
		 * because they may happen with finalizer processing.
		 */

		DUK_DDD(DUK_DDDPRINT("FINALFREE (allocated): %!iO",
		                     (duk_heaphdr *) curr));
		next = DUK_HEAPHDR_GET_NEXT(heap, curr);
		duk_heap_free_heaphdr_raw(heap, curr);
		curr = next;
	}
}

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_LOCAL void duk__free_finalize_list(duk_heap *heap) {
	duk_heaphdr *curr;
	duk_heaphdr *next;

	curr = heap->finalize_list;
	while (curr) {
		DUK_DDD(DUK_DDDPRINT("FINALFREE (finalize_list): %!iO",
		                     (duk_heaphdr *) curr));
		next = DUK_HEAPHDR_GET_NEXT(heap, curr);
		duk_heap_free_heaphdr_raw(heap, curr);
		curr = next;
	}
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

DUK_LOCAL void duk__free_stringtable(duk_heap *heap) {
	/* strings are only tracked by stringtable */
	duk_heap_strtable_free(heap);
}

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_LOCAL void duk__free_run_finalizers(duk_heap *heap) {
	duk_heaphdr *curr;
	duk_uint_t round_no;
	duk_size_t count_all;
	duk_size_t count_finalized;
	duk_size_t curr_limit;

	DUK_ASSERT(heap != NULL);

#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);  /* refzero not running -> must be empty */
#endif
	DUK_ASSERT(heap->finalize_list == NULL);  /* mark-and-sweep last pass */

	if (heap->heap_thread == NULL) {
		/* May happen when heap allocation fails right off.  There
		 * cannot be any finalizable objects in this case.
		 */
		DUK_D(DUK_DPRINT("no heap_thread in heap destruct, assume no finalizable objects"));
		return;
	}

	/* Prevent finalize_list processing and mark-and-sweep entirely.
	 * Setting ms_running != 0 also prevents refzero handling from moving
	 * objects away from the heap_allocated list.  The flag name is a bit
	 * misleading here.
	 *
	 * Use a distinct value for ms_running here (== 2) so that assertions
	 * can detect this situation separate from the normal runtime
	 * mark-and-sweep case.  This allows better assertions (GH-2030).
	 */
	DUK_ASSERT(heap->pf_prevent_count == 0);
	DUK_ASSERT(heap->ms_running == 0);
	DUK_ASSERT(heap->ms_prevent_count == 0);
	heap->pf_prevent_count = 1;
	heap->ms_running = 2;  /* Use distinguishable value. */
	heap->ms_prevent_count = 1;  /* Bump, because mark-and-sweep assumes it's bumped when ms_running is set. */

	curr_limit = 0;  /* suppress warning, not used */
	for (round_no = 0; ; round_no++) {
		curr = heap->heap_allocated;
		count_all = 0;
		count_finalized = 0;
		while (curr) {
			count_all++;
			if (DUK_HEAPHDR_IS_OBJECT(curr)) {
				/* Only objects in heap_allocated may have finalizers.  Check that
				 * the object itself has a _Finalizer property (own or inherited)
				 * so that we don't execute finalizers for e.g. Proxy objects.
				 */
				DUK_ASSERT(curr != NULL);

				if (DUK_HOBJECT_HAS_FINALIZER_FAST(heap, (duk_hobject *) curr)) {
					if (!DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) curr)) {
						DUK_ASSERT(DUK_HEAP_HAS_FINALIZER_NORESCUE(heap));  /* maps to finalizer 2nd argument */
						duk_heap_run_finalizer(heap, (duk_hobject *) curr);
						count_finalized++;
					}
				}
			}
			curr = DUK_HEAPHDR_GET_NEXT(heap, curr);
		}

		/* Each round of finalizer execution may spawn new finalizable objects
		 * which is normal behavior for some applications.  Allow multiple
		 * rounds of finalization, but use a shrinking limit based on the
		 * first round to detect the case where a runaway finalizer creates
		 * an unbounded amount of new finalizable objects.  Finalizer rescue
		 * is not supported: the semantics are unclear because most of the
		 * objects being finalized here are already reachable.  The finalizer
		 * is given a boolean to indicate that rescue is not possible.
		 *
		 * See discussion in: https://github.com/svaarala/duktape/pull/473
		 */

		if (round_no == 0) {
			/* Cannot wrap: each object is at least 8 bytes so count is
			 * at most 1/8 of that.
			 */
			curr_limit = count_all * 2;
		} else {
			curr_limit = (curr_limit * 3) / 4;   /* Decrease by 25% every round */
		}
		DUK_D(DUK_DPRINT("finalizer round %ld complete, %ld objects, tried to execute %ld finalizers, current limit is %ld",
		                 (long) round_no, (long) count_all, (long) count_finalized, (long) curr_limit));

		if (count_finalized == 0) {
			DUK_D(DUK_DPRINT("no more finalizable objects, forced finalization finished"));
			break;
		}
		if (count_finalized >= curr_limit) {
			DUK_D(DUK_DPRINT("finalizer count above limit, potentially runaway finalizer; skip remaining finalizers"));
			break;
		}
	}

	DUK_ASSERT(heap->ms_running == 2);
	DUK_ASSERT(heap->pf_prevent_count == 1);
	heap->ms_running = 0;
	heap->pf_prevent_count = 0;
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

DUK_INTERNAL void duk_heap_free(duk_heap *heap) {
	DUK_D(DUK_DPRINT("free heap: %p", (void *) heap));

#if defined(DUK_USE_DEBUG)
	duk_heap_strtable_dump(heap);
#endif

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	/* Detach a debugger if attached (can be called multiple times)
	 * safely.
	 */
	/* XXX: Add a flag to reject an attempt to re-attach?  Otherwise
	 * the detached callback may immediately reattach.
	 */
	duk_debug_do_detach(heap);
#endif

	/* Execute finalizers before freeing the heap, even for reachable
	 * objects.  This gives finalizers the chance to free any native
	 * resources like file handles, allocations made outside Duktape,
	 * etc.  This is quite tricky to get right, so that all finalizer
	 * guarantees are honored.
	 *
	 * Run mark-and-sweep a few times just in case (unreachable object
	 * finalizers run already here).  The last round must rescue objects
	 * from the previous round without running any more finalizers.  This
	 * ensures rescued objects get their FINALIZED flag cleared so that
	 * their finalizer is called once more in forced finalization to
	 * satisfy finalizer guarantees.  However, we don't want to run any
	 * more finalizers because that'd required one more loop, and so on.
	 *
	 * XXX: this perhaps requires an execution time limit.
	 */
	DUK_D(DUK_DPRINT("execute finalizers before freeing heap"));
	DUK_ASSERT(heap->pf_skip_finalizers == 0);
	DUK_D(DUK_DPRINT("forced gc #1 in heap destruction"));
	duk_heap_mark_and_sweep(heap, 0);
	DUK_D(DUK_DPRINT("forced gc #2 in heap destruction"));
	duk_heap_mark_and_sweep(heap, 0);
	DUK_D(DUK_DPRINT("forced gc #3 in heap destruction (don't run finalizers)"));
	heap->pf_skip_finalizers = 1;
	duk_heap_mark_and_sweep(heap, 0);  /* Skip finalizers; queue finalizable objects to heap_allocated. */

	/* There are never objects in refzero_list at this point, or at any
	 * point beyond a DECREF (even a DECREF_NORZ).  Since Duktape 2.1
	 * refzero_list processing is side effect free, so it is always
	 * processed to completion by a DECREF initially triggering a zero
	 * refcount.
	 */
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);  /* Always processed to completion inline. */
#endif
#if defined(DUK_USE_FINALIZER_SUPPORT)
	DUK_ASSERT(heap->finalize_list == NULL);  /* Last mark-and-sweep with skip_finalizers. */
#endif

#if defined(DUK_USE_FINALIZER_SUPPORT)
	DUK_D(DUK_DPRINT("run finalizers for remaining finalizable objects"));
	DUK_HEAP_SET_FINALIZER_NORESCUE(heap);  /* Rescue no longer supported. */
	duk__free_run_finalizers(heap);
#endif  /* DUK_USE_FINALIZER_SUPPORT */

	/* Note: heap->heap_thread, heap->curr_thread, and heap->heap_object
	 * are on the heap allocated list.
	 */

	DUK_D(DUK_DPRINT("freeing temporary freelists"));
	duk_heap_free_freelists(heap);

	DUK_D(DUK_DPRINT("freeing heap_allocated of heap: %p", (void *) heap));
	duk__free_allocated(heap);

#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);  /* Always processed to completion inline. */
#endif

#if defined(DUK_USE_FINALIZER_SUPPORT)
	DUK_D(DUK_DPRINT("freeing finalize_list of heap: %p", (void *) heap));
	duk__free_finalize_list(heap);
#endif

	DUK_D(DUK_DPRINT("freeing string table of heap: %p", (void *) heap));
	duk__free_stringtable(heap);

	DUK_D(DUK_DPRINT("freeing heap structure: %p", (void *) heap));
	heap->free_func(heap->heap_udata, heap);
}

/*
 *  Allocate a heap.
 *
 *  String table is initialized with built-in strings from genbuiltins.py,
 *  either by dynamically creating the strings or by referring to ROM strings.
 */

#if defined(DUK_USE_ROM_STRINGS)
DUK_LOCAL duk_bool_t duk__init_heap_strings(duk_heap *heap) {
#if defined(DUK_USE_ASSERTIONS)
	duk_small_uint_t i;
#endif

	DUK_UNREF(heap);

	/* With ROM-based strings, heap->strs[] and thr->strs[] are omitted
	 * so nothing to initialize for strs[].
	 */

#if defined(DUK_USE_ASSERTIONS)
	for (i = 0; i < sizeof(duk_rom_strings_lookup) / sizeof(const duk_hstring *); i++) {
		const duk_hstring *h;
		duk_uint32_t hash;

		h = duk_rom_strings_lookup[i];
		while (h != NULL) {
			hash = duk_heap_hashstring(heap, (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
			DUK_DD(DUK_DDPRINT("duk_rom_strings_lookup[%d] -> hash 0x%08lx, computed 0x%08lx",
			                   (int) i, (unsigned long) DUK_HSTRING_GET_HASH(h), (unsigned long) hash));
			DUK_ASSERT(hash == (duk_uint32_t) DUK_HSTRING_GET_HASH(h));

			h = (const duk_hstring *) h->hdr.h_next;
		}
	}
#endif
	return 1;
}
#else  /* DUK_USE_ROM_STRINGS */

DUK_LOCAL duk_bool_t duk__init_heap_strings(duk_heap *heap) {
	duk_bitdecoder_ctx bd_ctx;
	duk_bitdecoder_ctx *bd = &bd_ctx;  /* convenience */
	duk_small_uint_t i;

	duk_memzero(&bd_ctx, sizeof(bd_ctx));
	bd->data = (const duk_uint8_t *) duk_strings_data;
	bd->length = (duk_size_t) DUK_STRDATA_DATA_LENGTH;

	for (i = 0; i < DUK_HEAP_NUM_STRINGS; i++) {
		duk_uint8_t tmp[DUK_STRDATA_MAX_STRLEN];
		duk_small_uint_t len;
		duk_hstring *h;

		len = duk_bd_decode_bitpacked_string(bd, tmp);

		/* No need to length check string: it will never exceed even
		 * the 16-bit length maximum.
		 */
		DUK_ASSERT(len <= 0xffffUL);
		DUK_DDD(DUK_DDDPRINT("intern built-in string %ld", (long) i));
		h = duk_heap_strtable_intern(heap, tmp, len);
		if (!h) {
			goto failed;
		}
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h));

		/* Special flags checks.  Since these strings are always
		 * reachable and a string cannot appear twice in the string
		 * table, there's no need to check/set these flags elsewhere.
		 * The 'internal' flag is set by string intern code.
		 */
		if (i == DUK_STRIDX_EVAL || i == DUK_STRIDX_LC_ARGUMENTS) {
			DUK_HSTRING_SET_EVAL_OR_ARGUMENTS(h);
		}
		if (i >= DUK_STRIDX_START_RESERVED && i < DUK_STRIDX_END_RESERVED) {
			DUK_HSTRING_SET_RESERVED_WORD(h);
			if (i >= DUK_STRIDX_START_STRICT_RESERVED) {
				DUK_HSTRING_SET_STRICT_RESERVED_WORD(h);
			}
		}

		DUK_DDD(DUK_DDDPRINT("interned: %!O", (duk_heaphdr *) h));

		/* XXX: The incref macro takes a thread pointer but doesn't
		 * use it right now.
		 */
		DUK_HSTRING_INCREF(_never_referenced_, h);

#if defined(DUK_USE_HEAPPTR16)
		heap->strs16[i] = DUK_USE_HEAPPTR_ENC16(heap->heap_udata, (void *) h);
#else
		heap->strs[i] = h;
#endif
	}

	return 1;

 failed:
	return 0;
}
#endif  /* DUK_USE_ROM_STRINGS */

DUK_LOCAL duk_bool_t duk__init_heap_thread(duk_heap *heap) {
	duk_hthread *thr;

	DUK_D(DUK_DPRINT("heap init: alloc heap thread"));
	thr = duk_hthread_alloc_unchecked(heap,
	                                  DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                  DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_THREAD));
	if (thr == NULL) {
		DUK_D(DUK_DPRINT("failed to alloc heap_thread"));
		return 0;
	}
	thr->state = DUK_HTHREAD_STATE_INACTIVE;
#if defined(DUK_USE_ROM_STRINGS)
	/* No strs[] pointer. */
#else  /* DUK_USE_ROM_STRINGS */
#if defined(DUK_USE_HEAPPTR16)
	thr->strs16 = heap->strs16;
#else
	thr->strs = heap->strs;
#endif
#endif  /* DUK_USE_ROM_STRINGS */

	heap->heap_thread = thr;
	DUK_HTHREAD_INCREF(thr, thr);  /* Note: first argument not really used */

	/* 'thr' is now reachable */

	DUK_D(DUK_DPRINT("heap init: init heap thread stacks"));
	if (!duk_hthread_init_stacks(heap, thr)) {
		return 0;
	}

	/* XXX: this may now fail, and is not handled correctly */
	duk_hthread_create_builtin_objects(thr);

	/* default prototype */
	DUK_HOBJECT_SET_PROTOTYPE_INIT_INCREF(thr, (duk_hobject *) thr, thr->builtins[DUK_BIDX_THREAD_PROTOTYPE]);

	return 1;
}

#if defined(DUK_USE_DEBUG)
#define DUK__DUMPSZ(t)  do { \
		DUK_D(DUK_DPRINT("" #t "=%ld", (long) sizeof(t))); \
	} while (0)

/* These is not 100% because format would need to be non-portable "long long".
 * Also print out as doubles to catch cases where the "long" type is not wide
 * enough; the limits will then not be printed accurately but the magnitude
 * will be correct.
 */
#define DUK__DUMPLM_SIGNED_RAW(t,a,b)  do { \
		DUK_D(DUK_DPRINT(t "=[%ld,%ld]=[%lf,%lf]", \
		                 (long) (a), (long) (b), \
		                 (double) (a), (double) (b))); \
	} while (0)
#define DUK__DUMPLM_UNSIGNED_RAW(t,a,b)  do { \
		DUK_D(DUK_DPRINT(t "=[%lu,%lu]=[%lf,%lf]", \
		                 (unsigned long) (a), (unsigned long) (b), \
		                 (double) (a), (double) (b))); \
	} while (0)
#define DUK__DUMPLM_SIGNED(t)  do { \
		DUK__DUMPLM_SIGNED_RAW("DUK_" #t "_{MIN,MAX}", DUK_##t##_MIN, DUK_##t##_MAX); \
	} while (0)
#define DUK__DUMPLM_UNSIGNED(t)  do { \
		DUK__DUMPLM_UNSIGNED_RAW("DUK_" #t "_{MIN,MAX}", DUK_##t##_MIN, DUK_##t##_MAX); \
	} while (0)

DUK_LOCAL void duk__dump_type_sizes(void) {
	DUK_D(DUK_DPRINT("sizeof()"));

	/* basic platform types */
	DUK__DUMPSZ(char);
	DUK__DUMPSZ(short);
	DUK__DUMPSZ(int);
	DUK__DUMPSZ(long);
	DUK__DUMPSZ(double);
	DUK__DUMPSZ(void *);
	DUK__DUMPSZ(size_t);

	/* basic types from duk_features.h */
	DUK__DUMPSZ(duk_uint8_t);
	DUK__DUMPSZ(duk_int8_t);
	DUK__DUMPSZ(duk_uint16_t);
	DUK__DUMPSZ(duk_int16_t);
	DUK__DUMPSZ(duk_uint32_t);
	DUK__DUMPSZ(duk_int32_t);
	DUK__DUMPSZ(duk_uint64_t);
	DUK__DUMPSZ(duk_int64_t);
	DUK__DUMPSZ(duk_uint_least8_t);
	DUK__DUMPSZ(duk_int_least8_t);
	DUK__DUMPSZ(duk_uint_least16_t);
	DUK__DUMPSZ(duk_int_least16_t);
	DUK__DUMPSZ(duk_uint_least32_t);
	DUK__DUMPSZ(duk_int_least32_t);
#if defined(DUK_USE_64BIT_OPS)
	DUK__DUMPSZ(duk_uint_least64_t);
	DUK__DUMPSZ(duk_int_least64_t);
#endif
	DUK__DUMPSZ(duk_uint_fast8_t);
	DUK__DUMPSZ(duk_int_fast8_t);
	DUK__DUMPSZ(duk_uint_fast16_t);
	DUK__DUMPSZ(duk_int_fast16_t);
	DUK__DUMPSZ(duk_uint_fast32_t);
	DUK__DUMPSZ(duk_int_fast32_t);
#if defined(DUK_USE_64BIT_OPS)
	DUK__DUMPSZ(duk_uint_fast64_t);
	DUK__DUMPSZ(duk_int_fast64_t);
#endif
	DUK__DUMPSZ(duk_uintptr_t);
	DUK__DUMPSZ(duk_intptr_t);
	DUK__DUMPSZ(duk_uintmax_t);
	DUK__DUMPSZ(duk_intmax_t);
	DUK__DUMPSZ(duk_double_t);

	/* important chosen base types */
	DUK__DUMPSZ(duk_int_t);
	DUK__DUMPSZ(duk_uint_t);
	DUK__DUMPSZ(duk_int_fast_t);
	DUK__DUMPSZ(duk_uint_fast_t);
	DUK__DUMPSZ(duk_small_int_t);
	DUK__DUMPSZ(duk_small_uint_t);
	DUK__DUMPSZ(duk_small_int_fast_t);
	DUK__DUMPSZ(duk_small_uint_fast_t);

	/* some derived types */
	DUK__DUMPSZ(duk_codepoint_t);
	DUK__DUMPSZ(duk_ucodepoint_t);
	DUK__DUMPSZ(duk_idx_t);
	DUK__DUMPSZ(duk_errcode_t);
	DUK__DUMPSZ(duk_uarridx_t);

	/* tval */
	DUK__DUMPSZ(duk_double_union);
	DUK__DUMPSZ(duk_tval);

	/* structs from duk_forwdecl.h */
	DUK__DUMPSZ(duk_jmpbuf);  /* just one 'int' for C++ exceptions */
	DUK__DUMPSZ(duk_heaphdr);
	DUK__DUMPSZ(duk_heaphdr_string);
	DUK__DUMPSZ(duk_hstring);
	DUK__DUMPSZ(duk_hstring_external);
	DUK__DUMPSZ(duk_hobject);
	DUK__DUMPSZ(duk_harray);
	DUK__DUMPSZ(duk_hcompfunc);
	DUK__DUMPSZ(duk_hnatfunc);
	DUK__DUMPSZ(duk_hdecenv);
	DUK__DUMPSZ(duk_hobjenv);
	DUK__DUMPSZ(duk_hthread);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	DUK__DUMPSZ(duk_hbufobj);
#endif
	DUK__DUMPSZ(duk_hproxy);
	DUK__DUMPSZ(duk_hbuffer);
	DUK__DUMPSZ(duk_hbuffer_fixed);
	DUK__DUMPSZ(duk_hbuffer_dynamic);
	DUK__DUMPSZ(duk_hbuffer_external);
	DUK__DUMPSZ(duk_propaccessor);
	DUK__DUMPSZ(duk_propvalue);
	DUK__DUMPSZ(duk_propdesc);
	DUK__DUMPSZ(duk_heap);
	DUK__DUMPSZ(duk_activation);
	DUK__DUMPSZ(duk_catcher);
	DUK__DUMPSZ(duk_strcache_entry);
	DUK__DUMPSZ(duk_litcache_entry);
	DUK__DUMPSZ(duk_ljstate);
	DUK__DUMPSZ(duk_fixedbuffer);
	DUK__DUMPSZ(duk_bitdecoder_ctx);
	DUK__DUMPSZ(duk_bitencoder_ctx);
	DUK__DUMPSZ(duk_token);
	DUK__DUMPSZ(duk_re_token);
	DUK__DUMPSZ(duk_lexer_point);
	DUK__DUMPSZ(duk_lexer_ctx);
	DUK__DUMPSZ(duk_compiler_instr);
	DUK__DUMPSZ(duk_compiler_func);
	DUK__DUMPSZ(duk_compiler_ctx);
	DUK__DUMPSZ(duk_re_matcher_ctx);
	DUK__DUMPSZ(duk_re_compiler_ctx);
}
DUK_LOCAL void duk__dump_type_limits(void) {
	DUK_D(DUK_DPRINT("limits"));

	/* basic types */
	DUK__DUMPLM_SIGNED(INT8);
	DUK__DUMPLM_UNSIGNED(UINT8);
	DUK__DUMPLM_SIGNED(INT_FAST8);
	DUK__DUMPLM_UNSIGNED(UINT_FAST8);
	DUK__DUMPLM_SIGNED(INT_LEAST8);
	DUK__DUMPLM_UNSIGNED(UINT_LEAST8);
	DUK__DUMPLM_SIGNED(INT16);
	DUK__DUMPLM_UNSIGNED(UINT16);
	DUK__DUMPLM_SIGNED(INT_FAST16);
	DUK__DUMPLM_UNSIGNED(UINT_FAST16);
	DUK__DUMPLM_SIGNED(INT_LEAST16);
	DUK__DUMPLM_UNSIGNED(UINT_LEAST16);
	DUK__DUMPLM_SIGNED(INT32);
	DUK__DUMPLM_UNSIGNED(UINT32);
	DUK__DUMPLM_SIGNED(INT_FAST32);
	DUK__DUMPLM_UNSIGNED(UINT_FAST32);
	DUK__DUMPLM_SIGNED(INT_LEAST32);
	DUK__DUMPLM_UNSIGNED(UINT_LEAST32);
#if defined(DUK_USE_64BIT_OPS)
	DUK__DUMPLM_SIGNED(INT64);
	DUK__DUMPLM_UNSIGNED(UINT64);
	DUK__DUMPLM_SIGNED(INT_FAST64);
	DUK__DUMPLM_UNSIGNED(UINT_FAST64);
	DUK__DUMPLM_SIGNED(INT_LEAST64);
	DUK__DUMPLM_UNSIGNED(UINT_LEAST64);
#endif
	DUK__DUMPLM_SIGNED(INTPTR);
	DUK__DUMPLM_UNSIGNED(UINTPTR);
	DUK__DUMPLM_SIGNED(INTMAX);
	DUK__DUMPLM_UNSIGNED(UINTMAX);

	/* derived types */
	DUK__DUMPLM_SIGNED(INT);
	DUK__DUMPLM_UNSIGNED(UINT);
	DUK__DUMPLM_SIGNED(INT_FAST);
	DUK__DUMPLM_UNSIGNED(UINT_FAST);
	DUK__DUMPLM_SIGNED(SMALL_INT);
	DUK__DUMPLM_UNSIGNED(SMALL_UINT);
	DUK__DUMPLM_SIGNED(SMALL_INT_FAST);
	DUK__DUMPLM_UNSIGNED(SMALL_UINT_FAST);
}

DUK_LOCAL void duk__dump_misc_options(void) {
	DUK_D(DUK_DPRINT("DUK_VERSION: %ld", (long) DUK_VERSION));
	DUK_D(DUK_DPRINT("DUK_GIT_DESCRIBE: %s", DUK_GIT_DESCRIBE));
	DUK_D(DUK_DPRINT("OS string: %s", DUK_USE_OS_STRING));
	DUK_D(DUK_DPRINT("architecture string: %s", DUK_USE_ARCH_STRING));
	DUK_D(DUK_DPRINT("compiler string: %s", DUK_USE_COMPILER_STRING));
	DUK_D(DUK_DPRINT("debug level: %ld", (long) DUK_USE_DEBUG_LEVEL));
#if defined(DUK_USE_PACKED_TVAL)
	DUK_D(DUK_DPRINT("DUK_USE_PACKED_TVAL: yes"));
#else
	DUK_D(DUK_DPRINT("DUK_USE_PACKED_TVAL: no"));
#endif
#if defined(DUK_USE_VARIADIC_MACROS)
	DUK_D(DUK_DPRINT("DUK_USE_VARIADIC_MACROS: yes"));
#else
	DUK_D(DUK_DPRINT("DUK_USE_VARIADIC_MACROS: no"));
#endif
#if defined(DUK_USE_INTEGER_LE)
	DUK_D(DUK_DPRINT("integer endianness: little"));
#elif defined(DUK_USE_INTEGER_ME)
	DUK_D(DUK_DPRINT("integer endianness: mixed"));
#elif defined(DUK_USE_INTEGER_BE)
	DUK_D(DUK_DPRINT("integer endianness: big"));
#else
	DUK_D(DUK_DPRINT("integer endianness: ???"));
#endif
#if defined(DUK_USE_DOUBLE_LE)
	DUK_D(DUK_DPRINT("IEEE double endianness: little"));
#elif defined(DUK_USE_DOUBLE_ME)
	DUK_D(DUK_DPRINT("IEEE double endianness: mixed"));
#elif defined(DUK_USE_DOUBLE_BE)
	DUK_D(DUK_DPRINT("IEEE double endianness: big"));
#else
	DUK_D(DUK_DPRINT("IEEE double endianness: ???"));
#endif
}
#endif  /* DUK_USE_DEBUG */

DUK_INTERNAL
duk_heap *duk_heap_alloc(duk_alloc_function alloc_func,
                         duk_realloc_function realloc_func,
                         duk_free_function free_func,
                         void *heap_udata,
                         duk_fatal_function fatal_func) {
	duk_heap *res = NULL;
	duk_uint32_t st_initsize;

	DUK_D(DUK_DPRINT("allocate heap"));

	/*
	 *  Random config sanity asserts
	 */

	DUK_ASSERT(DUK_USE_STRTAB_MINSIZE >= 64);

	DUK_ASSERT((DUK_HTYPE_STRING & 0x01U) == 0);
	DUK_ASSERT((DUK_HTYPE_BUFFER & 0x01U) == 0);
	DUK_ASSERT((DUK_HTYPE_OBJECT & 0x01U) == 1);  /* DUK_HEAPHDR_IS_OBJECT() relies ont his. */

	/*
	 *  Debug dump type sizes
	 */

#if defined(DUK_USE_DEBUG)
	duk__dump_misc_options();
	duk__dump_type_sizes();
	duk__dump_type_limits();
#endif

	/*
	 *  If selftests enabled, run them as early as possible.
	 */

#if defined(DUK_USE_SELF_TESTS)
	DUK_D(DUK_DPRINT("run self tests"));
	if (duk_selftest_run_tests(alloc_func, realloc_func, free_func, heap_udata) > 0) {
		fatal_func(heap_udata, "self test(s) failed");
	}
	DUK_D(DUK_DPRINT("self tests passed"));
#endif

	/*
	 *  Important assert-like checks that should be enabled even
	 *  when assertions are otherwise not enabled.
	 */

#if defined(DUK_USE_EXEC_REGCONST_OPTIMIZE)
	/* Can't check sizeof() using preprocessor so explicit check.
	 * This will be optimized away in practice; unfortunately a
	 * warning is generated on some compilers as a result.
	 */
#if defined(DUK_USE_PACKED_TVAL)
	if (sizeof(duk_tval) != 8) {
#else
	if (sizeof(duk_tval) != 16) {
#endif
		fatal_func(heap_udata, "sizeof(duk_tval) not 8 or 16, cannot use DUK_USE_EXEC_REGCONST_OPTIMIZE option");
	}
#endif  /* DUK_USE_EXEC_REGCONST_OPTIMIZE */

	/*
	 *  Computed values (e.g. INFINITY)
	 */

#if defined(DUK_USE_COMPUTED_NAN)
	do {
		/* Workaround for some exotic platforms where NAN is missing
		 * and the expression (0.0 / 0.0) does NOT result in a NaN.
		 * Such platforms use the global 'duk_computed_nan' which must
		 * be initialized at runtime.  Use 'volatile' to ensure that
		 * the compiler will actually do the computation and not try
		 * to do constant folding which might result in the original
		 * problem.
		 */
		volatile double dbl1 = 0.0;
		volatile double dbl2 = 0.0;
		duk_computed_nan = dbl1 / dbl2;
	} while (0);
#endif

#if defined(DUK_USE_COMPUTED_INFINITY)
	do {
		/* Similar workaround for INFINITY. */
		volatile double dbl1 = 1.0;
		volatile double dbl2 = 0.0;
		duk_computed_infinity = dbl1 / dbl2;
	} while (0);
#endif

	/*
	 *  Allocate heap struct
	 *
	 *  Use a raw call, all macros expect the heap to be initialized
	 */

#if defined(DUK_USE_INJECT_HEAP_ALLOC_ERROR) && (DUK_USE_INJECT_HEAP_ALLOC_ERROR == 1)
	goto failed;
#endif
	DUK_D(DUK_DPRINT("alloc duk_heap object"));
	res = (duk_heap *) alloc_func(heap_udata, sizeof(duk_heap));
	if (!res) {
		goto failed;
	}

	/*
	 *  Zero the struct, and start initializing roughly in order
	 */

	duk_memzero(res, sizeof(*res));
#if defined(DUK_USE_ASSERTIONS)
	res->heap_initializing = 1;
#endif

	/* explicit NULL inits */
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->heap_udata = NULL;
	res->heap_allocated = NULL;
#if defined(DUK_USE_REFERENCE_COUNTING)
	res->refzero_list = NULL;
#endif
#if defined(DUK_USE_FINALIZER_SUPPORT)
	res->finalize_list = NULL;
#if defined(DUK_USE_ASSERTIONS)
	res->currently_finalizing = NULL;
#endif
#endif
#if defined(DUK_USE_CACHE_ACTIVATION)
	res->activation_free = NULL;
#endif
#if defined(DUK_USE_CACHE_CATCHER)
	res->catcher_free = NULL;
#endif
	res->heap_thread = NULL;
	res->curr_thread = NULL;
	res->heap_object = NULL;
#if defined(DUK_USE_STRTAB_PTRCOMP)
	res->strtable16 = NULL;
#else
	res->strtable = NULL;
#endif
#if defined(DUK_USE_ROM_STRINGS)
	/* no res->strs[] */
#else  /* DUK_USE_ROM_STRINGS */
#if defined(DUK_USE_HEAPPTR16)
	/* res->strs16[] is zeroed and zero decodes to NULL, so no NULL inits. */
#else
	{
		duk_small_uint_t i;
	        for (i = 0; i < DUK_HEAP_NUM_STRINGS; i++) {
			res->strs[i] = NULL;
	        }
	}
#endif
#endif  /* DUK_USE_ROM_STRINGS */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	res->dbg_read_cb = NULL;
	res->dbg_write_cb = NULL;
	res->dbg_peek_cb = NULL;
	res->dbg_read_flush_cb = NULL;
	res->dbg_write_flush_cb = NULL;
	res->dbg_request_cb = NULL;
	res->dbg_udata = NULL;
	res->dbg_pause_act = NULL;
#endif
#endif  /* DUK_USE_EXPLICIT_NULL_INIT */

	res->alloc_func = alloc_func;
	res->realloc_func = realloc_func;
	res->free_func = free_func;
	res->heap_udata = heap_udata;
	res->fatal_func = fatal_func;

	/* XXX: for now there's a pointer packing zero assumption, i.e.
	 * NULL <=> compressed pointer 0.  If this is removed, may need
	 * to precompute e.g. null16 here.
	 */

	/* res->ms_trigger_counter == 0 -> now causes immediate GC; which is OK */

	/* Prevent mark-and-sweep and finalizer execution until heap is completely
	 * initialized.
	 */
	DUK_ASSERT(res->ms_prevent_count == 0);
	DUK_ASSERT(res->pf_prevent_count == 0);
	res->ms_prevent_count = 1;
	res->pf_prevent_count = 1;
	DUK_ASSERT(res->ms_running == 0);

	res->call_recursion_depth = 0;
	res->call_recursion_limit = DUK_USE_NATIVE_CALL_RECLIMIT;

	/* XXX: use the pointer as a seed for now: mix in time at least */

	/* The casts through duk_uintptr_t is to avoid the following GCC warning:
	 *
	 *   warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
	 *
	 * This still generates a /Wp64 warning on VS2010 when compiling for x86.
	 */
#if defined(DUK_USE_ROM_STRINGS)
	/* XXX: make a common DUK_USE_ option, and allow custom fixed seed? */
	DUK_D(DUK_DPRINT("using rom strings, force heap hash_seed to fixed value 0x%08lx", (long) DUK__FIXED_HASH_SEED));
	res->hash_seed = (duk_uint32_t) DUK__FIXED_HASH_SEED;
#else  /* DUK_USE_ROM_STRINGS */
	res->hash_seed = (duk_uint32_t) (duk_uintptr_t) res;
#if !defined(DUK_USE_STRHASH_DENSE)
	res->hash_seed ^= 5381;  /* Bernstein hash init value is normally 5381; XOR it in in case pointer low bits are 0 */
#endif
#endif  /* DUK_USE_ROM_STRINGS */

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->lj.jmpbuf_ptr = NULL;
#endif
	DUK_ASSERT(res->lj.type == DUK_LJ_TYPE_UNKNOWN);  /* zero */
	DUK_ASSERT(res->lj.iserror == 0);
	DUK_TVAL_SET_UNDEFINED(&res->lj.value1);
	DUK_TVAL_SET_UNDEFINED(&res->lj.value2);

	DUK_ASSERT_LJSTATE_UNSET(res);

	/*
	 *  Init stringtable: fixed variant
	 */

	st_initsize = DUK_USE_STRTAB_MINSIZE;
#if defined(DUK_USE_STRTAB_PTRCOMP)
	res->strtable16 = (duk_uint16_t *) alloc_func(heap_udata, sizeof(duk_uint16_t) * st_initsize);
	if (res->strtable16 == NULL) {
		goto failed;
	}
#else
	res->strtable = (duk_hstring **) alloc_func(heap_udata, sizeof(duk_hstring *) * st_initsize);
	if (res->strtable == NULL) {
		goto failed;
	}
#endif
	res->st_size = st_initsize;
	res->st_mask = st_initsize - 1;
#if (DUK_USE_STRTAB_MINSIZE != DUK_USE_STRTAB_MAXSIZE)
	DUK_ASSERT(res->st_count == 0);
#endif

#if defined(DUK_USE_STRTAB_PTRCOMP)
	/* zero assumption */
	duk_memzero(res->strtable16, sizeof(duk_uint16_t) * st_initsize);
#else
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	{
		duk_uint32_t i;
	        for (i = 0; i < st_initsize; i++) {
			res->strtable[i] = NULL;
	        }
	}
#else
	duk_memzero(res->strtable, sizeof(duk_hstring *) * st_initsize);
#endif  /* DUK_USE_EXPLICIT_NULL_INIT */
#endif  /* DUK_USE_STRTAB_PTRCOMP */

	/*
	 *  Init stringcache
	 */

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	{
		duk_uint_t i;
		for (i = 0; i < DUK_HEAP_STRCACHE_SIZE; i++) {
			res->strcache[i].h = NULL;
		}
	}
#endif

	/*
	 *  Init litcache
	 */
#if defined(DUK_USE_LITCACHE_SIZE)
	DUK_ASSERT(DUK_USE_LITCACHE_SIZE > 0);
	DUK_ASSERT(DUK_IS_POWER_OF_TWO((duk_uint_t) DUK_USE_LITCACHE_SIZE));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	{
		duk_uint_t i;
		for (i = 0; i < DUK_USE_LITCACHE_SIZE; i++) {
			res->litcache[i].addr = NULL;
			res->litcache[i].h = NULL;
		}
	}
#endif
#endif  /* DUK_USE_LITCACHE_SIZE */

	/* XXX: error handling is incomplete.  It would be cleanest if
	 * there was a setjmp catchpoint, so that all init code could
	 * freely throw errors.  If that were the case, the return code
	 * passing here could be removed.
	 */

	/*
	 *  Init built-in strings
	 */

#if defined(DUK_USE_INJECT_HEAP_ALLOC_ERROR) && (DUK_USE_INJECT_HEAP_ALLOC_ERROR == 2)
	goto failed;
#endif
	DUK_D(DUK_DPRINT("heap init: initialize heap strings"));
	if (!duk__init_heap_strings(res)) {
		goto failed;
	}

	/*
	 *  Init the heap thread
	 */

#if defined(DUK_USE_INJECT_HEAP_ALLOC_ERROR) && (DUK_USE_INJECT_HEAP_ALLOC_ERROR == 3)
	goto failed;
#endif
	DUK_D(DUK_DPRINT("heap init: initialize heap thread"));
	if (!duk__init_heap_thread(res)) {
		goto failed;
	}

	/*
	 *  Init the heap object
	 */

#if defined(DUK_USE_INJECT_HEAP_ALLOC_ERROR) && (DUK_USE_INJECT_HEAP_ALLOC_ERROR == 4)
	goto failed;
#endif
	DUK_D(DUK_DPRINT("heap init: initialize heap object"));
	DUK_ASSERT(res->heap_thread != NULL);
	res->heap_object = duk_hobject_alloc_unchecked(res, DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                                    DUK_HOBJECT_FLAG_FASTREFS |
	                                                    DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT));
	if (res->heap_object == NULL) {
		goto failed;
	}
	DUK_HOBJECT_INCREF(res->heap_thread, res->heap_object);

	/*
	 *  Odds and ends depending on the heap thread
	 */

#if !defined(DUK_USE_GET_RANDOM_DOUBLE)
#if defined(DUK_USE_PREFER_SIZE) || !defined(DUK_USE_64BIT_OPS)
	res->rnd_state = (duk_uint32_t) duk_time_get_ecmascript_time(res->heap_thread);
	duk_util_tinyrandom_prepare_seed(res->heap_thread);
#else
	res->rnd_state[0] = (duk_uint64_t) duk_time_get_ecmascript_time(res->heap_thread);
	DUK_ASSERT(res->rnd_state[1] == 0);  /* Not filled here, filled in by seed preparation. */
#if 0  /* Manual test values matching misc/xoroshiro128plus_test.c. */
	res->rnd_state[0] = DUK_U64_CONSTANT(0xdeadbeef12345678);
	res->rnd_state[1] = DUK_U64_CONSTANT(0xcafed00d12345678);
#endif
	duk_util_tinyrandom_prepare_seed(res->heap_thread);
	/* Mix in heap pointer: this ensures that if two Duktape heaps are
	 * created on the same millisecond, they get a different PRNG
	 * sequence (unless e.g. virtual memory addresses cause also the
	 * heap object pointer to be the same).
	 */
	{
		duk_uint64_t tmp_u64;
		tmp_u64 = 0;
		duk_memcpy((void *) &tmp_u64,
		           (const void *) &res,
		           (size_t) (sizeof(void *) >= sizeof(duk_uint64_t) ? sizeof(duk_uint64_t) : sizeof(void *)));
		res->rnd_state[1] ^= tmp_u64;
	}
	do {
		duk_small_uint_t i;
		for (i = 0; i < 10; i++) {
			/* Throw away a few initial random numbers just in
			 * case.  Probably unnecessary due to SplitMix64
			 * preparation.
			 */
			(void) duk_util_tinyrandom_get_double(res->heap_thread);
		}
	} while (0);
#endif
#endif

	/*
	 *  Allow finalizer and mark-and-sweep processing.
	 */

	DUK_D(DUK_DPRINT("heap init: allow finalizer/mark-and-sweep processing"));
	DUK_ASSERT(res->ms_prevent_count == 1);
	DUK_ASSERT(res->pf_prevent_count == 1);
	res->ms_prevent_count = 0;
	res->pf_prevent_count = 0;
	DUK_ASSERT(res->ms_running == 0);
#if defined(DUK_USE_ASSERTIONS)
	res->heap_initializing = 0;
#endif

	/*
	 *  All done.
	 */

	DUK_D(DUK_DPRINT("allocated heap: %p", (void *) res));
	return res;

 failed:
	DUK_D(DUK_DPRINT("heap allocation failed"));

	if (res != NULL) {
		/* Assumes that allocated pointers and alloc funcs are valid
		 * if res exists.
		 */
		DUK_ASSERT(res->ms_prevent_count == 1);
		DUK_ASSERT(res->pf_prevent_count == 1);
		DUK_ASSERT(res->ms_running == 0);
		if (res->heap_thread != NULL) {
			res->ms_prevent_count = 0;
			res->pf_prevent_count = 0;
		}
#if defined(DUK_USE_ASSERTIONS)
		res->heap_initializing = 0;
#endif

		DUK_ASSERT(res->alloc_func != NULL);
		DUK_ASSERT(res->realloc_func != NULL);
		DUK_ASSERT(res->free_func != NULL);
		duk_heap_free(res);
	}

	return NULL;
}

/* automatic undefs */
#undef DUK__DUMPLM_SIGNED
#undef DUK__DUMPLM_SIGNED_RAW
#undef DUK__DUMPLM_UNSIGNED
#undef DUK__DUMPLM_UNSIGNED_RAW
#undef DUK__DUMPSZ
#undef DUK__FIXED_HASH_SEED
/*
 *  Finalizer handling.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_FINALIZER_SUPPORT)

/*
 *  Fake torture finalizer.
 */

#if defined(DUK_USE_FINALIZER_TORTURE)
DUK_LOCAL duk_ret_t duk__fake_global_finalizer(duk_hthread *thr) {
	DUK_DD(DUK_DDPRINT("fake global torture finalizer executed"));

	/* Require a lot of stack to force a value stack grow/shrink. */
	duk_require_stack(thr, 100000);

	/* Force a reallocation with pointer change for value stack
	 * to maximize side effects.
	 */
	duk_hthread_valstack_torture_realloc(thr);

	/* Inner function call, error throw. */
	duk_eval_string_noresult(thr,
		"(function dummy() {\n"
		"    dummy.prototype = null;  /* break reference loop */\n"
		"    try {\n"
		"        throw 'fake-finalizer-dummy-error';\n"
		"    } catch (e) {\n"
		"        void e;\n"
		"    }\n"
		"})()");

	/* The above creates garbage (e.g. a function instance).  Because
	 * the function/prototype reference loop is broken, it gets collected
	 * immediately by DECREF.  If Function.prototype has a _Finalizer
	 * property (happens in some test cases), the garbage gets queued to
	 * finalize_list.  This still won't cause an infinite loop because
	 * the torture finalizer is called once per finalize_list run and
	 * the garbage gets handled in the same run.  (If the garbage needs
	 * mark-and-sweep collection, an infinite loop might ensue.)
	 */
	return 0;
}

DUK_LOCAL void duk__run_global_torture_finalizer(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);

	/* Avoid fake finalization when callstack limit is near.  Otherwise
	 * a callstack limit error will be created, then refzero'ed.  The
	 * +5 headroom is conservative.
	 */
	if (thr->heap->call_recursion_depth + 5 >= thr->heap->call_recursion_limit ||
	    thr->callstack_top + 5 >= DUK_USE_CALLSTACK_LIMIT) {
		DUK_D(DUK_DPRINT("skip global torture finalizer, too little headroom for call recursion or call stack size"));
		return;
	}

	/* Run fake finalizer.  Avoid creating unnecessary garbage. */
	duk_push_c_function(thr, duk__fake_global_finalizer, 0 /*nargs*/);
	(void) duk_pcall(thr, 0 /*nargs*/);
	duk_pop(thr);
}
#endif  /* DUK_USE_FINALIZER_TORTURE */

/*
 *  Process the finalize_list to completion.
 *
 *  An object may be placed on finalize_list by either refcounting or
 *  mark-and-sweep.  The refcount of objects placed by refcounting will be
 *  zero; the refcount of objects placed by mark-and-sweep is > 0.  In both
 *  cases the refcount is bumped by 1 artificially so that a REFZERO event
 *  can never happen while an object is waiting for finalization.  Without
 *  this bump a REFZERO could now happen because user code may call
 *  duk_push_heapptr() and then pop a value even when it's on finalize_list.
 *
 *  List processing assumes refcounts are kept up-to-date at all times, so
 *  that once the finalizer returns, a zero refcount is a reliable reason to
 *  free the object immediately rather than place it back to the heap.  This
 *  is the case because we run outside of refzero_list processing so that
 *  DECREF cascades are handled fully inline.
 *
 *  For mark-and-sweep queued objects (had_zero_refcount false) the object
 *  may be freed immediately if its refcount is zero after the finalizer call
 *  (i.e. finalizer removed the reference loop for the object).  If not, the
 *  next mark-and-sweep will collect the object unless it has become reachable
 *  (i.e. rescued) by that time and its refcount hasn't fallen to zero before
 *  that.  Mark-and-sweep detects these objects because their FINALIZED flag
 *  is set.
 *
 *  There's an inherent limitation for mark-and-sweep finalizer rescuing: an
 *  object won't get refinalized if (1) it's rescued, but (2) becomes
 *  unreachable before mark-and-sweep has had time to notice it.  The next
 *  mark-and-sweep round simply doesn't have any information of whether the
 *  object has been unreachable the whole time or not (the only way to get
 *  that information would be a mark-and-sweep pass for *every finalized
 *  object*).  This is awkward for the application because the mark-and-sweep
 *  round is not generally visible or under full application control.
 *
 *  For refcount queued objects (had_zero_refcount true) the object is either
 *  immediately freed or rescued, and waiting for a mark-and-sweep round is not
 *  necessary (or desirable); FINALIZED is cleared when a rescued object is
 *  queued back to heap_allocated.  The object is eligible for finalization
 *  again (either via refcounting or mark-and-sweep) immediately after being
 *  rescued.  If a refcount finalized object is placed into an unreachable
 *  reference loop by its finalizer, it will get collected by mark-and-sweep
 *  and currently the finalizer will execute again.
 *
 *  There's a special case where:
 *
 *    - Mark-and-sweep queues an object to finalize_list for finalization.
 *    - The finalizer is executed, FINALIZED is set, and object is queued
 *      back to heap_allocated, waiting for a new mark-and-sweep round.
 *    - The object's refcount drops to zero before mark-and-sweep has a
 *      chance to run another round and make a rescue/free decision.
 *
 *  This is now handled by refzero code: if an object has a finalizer but
 *  FINALIZED is already set, the object is freed without finalizer processing.
 *  The outcome is the same as if mark-and-sweep was executed at that point;
 *  mark-and-sweep would also free the object without another finalizer run.
 *  This could also be changed so that the refzero-triggered finalizer *IS*
 *  executed: being refzero collected implies someone has operated on the
 *  object so it hasn't been totally unreachable the whole time.  This would
 *  risk a finalizer loop however.
 */

DUK_INTERNAL void duk_heap_process_finalize_list(duk_heap *heap) {
	duk_heaphdr *curr;
#if defined(DUK_USE_DEBUG)
	duk_size_t count = 0;
#endif

	DUK_DDD(DUK_DDDPRINT("duk_heap_process_finalize_list: %p", (void *) heap));

	if (heap->pf_prevent_count != 0) {
		DUK_DDD(DUK_DDDPRINT("skip finalize_list processing: pf_prevent_count != 0"));
		return;
	}

	/* Heap alloc prevents mark-and-sweep before heap_thread is ready. */
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(heap->heap_thread->valstack != NULL);
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);
#endif

	DUK_ASSERT(heap->pf_prevent_count == 0);
	heap->pf_prevent_count = 1;

	/* Mark-and-sweep no longer needs to be prevented when running
	 * finalizers: mark-and-sweep skips any rescue decisions if there
	 * are any objects in finalize_list when mark-and-sweep is entered.
	 * This protects finalized objects from incorrect rescue decisions
	 * caused by finalize_list being a reachability root and only
	 * partially processed.  Freeing decisions are not postponed.
	 */

	/* When finalizer torture is enabled, make a fake finalizer call with
	 * maximum side effects regardless of whether finalize_list is empty.
	 */
#if defined(DUK_USE_FINALIZER_TORTURE)
	duk__run_global_torture_finalizer(heap->heap_thread);
#endif

	/* Process finalize_list until it becomes empty.  There's currently no
	 * protection against a finalizer always creating more garbage.
	 */
	while ((curr = heap->finalize_list) != NULL) {
#if defined(DUK_USE_REFERENCE_COUNTING)
		duk_bool_t queue_back;
#endif

		DUK_DD(DUK_DDPRINT("processing finalize_list entry: %p -> %!iO", (void *) curr, curr));

		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);  /* Only objects have finalizers. */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr));
		DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(curr));
		DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZABLE(curr));  /* All objects on finalize_list will have this flag (except object being finalized right now). */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));   /* Queueing code ensures. */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(curr));  /* ROM objects never get freed (or finalized). */

#if defined(DUK_USE_ASSERTIONS)
		DUK_ASSERT(heap->currently_finalizing == NULL);
		heap->currently_finalizing = curr;
#endif

		/* Clear FINALIZABLE for object being finalized, so that
		 * duk_push_heapptr() can properly ignore the object.
		 */
		DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);

		if (DUK_LIKELY(!heap->pf_skip_finalizers)) {
			/* Run the finalizer, duk_heap_run_finalizer() sets
			 * and checks for FINALIZED to prevent the finalizer
			 * from executing multiple times per finalization cycle.
			 * (This safeguard shouldn't be actually needed anymore).
			 */

#if defined(DUK_USE_REFERENCE_COUNTING)
			duk_bool_t had_zero_refcount;
#endif

			/* The object's refcount is >0 throughout so it won't be
			 * refzero processed prematurely.
			 */
#if defined(DUK_USE_REFERENCE_COUNTING)
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) >= 1);
			had_zero_refcount = (DUK_HEAPHDR_GET_REFCOUNT(curr) == 1);  /* Preincremented on finalize_list insert. */
#endif

			DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
			duk_heap_run_finalizer(heap, (duk_hobject *) curr);  /* must never longjmp */
			DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZED(curr));
			/* XXX: assert that object is still in finalize_list
			 * when duk_push_heapptr() allows automatic rescue.
			 */

#if defined(DUK_USE_REFERENCE_COUNTING)
			DUK_DD(DUK_DDPRINT("refcount after finalizer (includes bump): %ld", (long) DUK_HEAPHDR_GET_REFCOUNT(curr)));
			if (DUK_HEAPHDR_GET_REFCOUNT(curr) == 1) {  /* Only artificial bump in refcount? */
#if defined(DUK_USE_DEBUG)
				if (had_zero_refcount) {
					DUK_DD(DUK_DDPRINT("finalized object's refcount is zero -> free immediately (refcount queued)"));
				} else {
					DUK_DD(DUK_DDPRINT("finalized object's refcount is zero -> free immediately (mark-and-sweep queued)"));
				}
#endif
				queue_back = 0;
			} else
#endif
			{
#if defined(DUK_USE_REFERENCE_COUNTING)
				queue_back = 1;
				if (had_zero_refcount) {
					/* When finalization is triggered
					 * by refzero and we queue the object
					 * back, clear FINALIZED right away
					 * so that the object can be refinalized
					 * immediately if necessary.
					 */
					DUK_HEAPHDR_CLEAR_FINALIZED(curr);
				}
#endif
			}
		} else {
			/* Used during heap destruction: don't actually run finalizers
			 * because we're heading into forced finalization.  Instead,
			 * queue finalizable objects back to the heap_allocated list.
			 */
			DUK_D(DUK_DPRINT("skip finalizers flag set, queue object to heap_allocated without finalizing"));
			DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
#if defined(DUK_USE_REFERENCE_COUNTING)
			queue_back = 1;
#endif
		}

		/* Dequeue object from finalize_list.  Note that 'curr' may no
		 * longer be finalize_list head because new objects may have
		 * been queued to the list.  As a result we can't optimize for
		 * the single-linked heap case and must scan the list for
		 * removal, typically the scan is very short however.
		 */
		DUK_HEAP_REMOVE_FROM_FINALIZE_LIST(heap, curr);

		/* Queue back to heap_allocated or free immediately. */
#if defined(DUK_USE_REFERENCE_COUNTING)
		if (queue_back) {
			/* FINALIZED is only cleared if object originally
			 * queued for finalization by refcounting.  For
			 * mark-and-sweep FINALIZED is left set, so that
			 * next mark-and-sweep round can make a rescue/free
			 * decision.
			 */
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) >= 1);
			DUK_HEAPHDR_PREDEC_REFCOUNT(curr);  /* Remove artificial refcount bump. */
			DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);
			DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, curr);
		} else {
			/* No need to remove the refcount bump here. */
			DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);  /* currently, always the case */
			DUK_DD(DUK_DDPRINT("refcount finalize after finalizer call: %!O", curr));
			duk_hobject_refcount_finalize_norz(heap, (duk_hobject *) curr);
			duk_free_hobject(heap, (duk_hobject *) curr);
			DUK_DD(DUK_DDPRINT("freed hobject after finalization: %p", (void *) curr));
		}
#else  /* DUK_USE_REFERENCE_COUNTING */
		DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);
		DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, curr);
#endif  /* DUK_USE_REFERENCE_COUNTING */

#if defined(DUK_USE_DEBUG)
		count++;
#endif

#if defined(DUK_USE_ASSERTIONS)
		DUK_ASSERT(heap->currently_finalizing != NULL);
		heap->currently_finalizing = NULL;
#endif
	}

	/* finalize_list will always be processed completely. */
	DUK_ASSERT(heap->finalize_list == NULL);

#if 0
	/* While NORZ macros are used above, this is unnecessary because the
	 * only pending side effects are now finalizers, and finalize_list is
	 * empty.
	 */
	DUK_REFZERO_CHECK_SLOW(heap->heap_thread);
#endif

	/* Prevent count may be bumped while finalizers run, but should always
	 * be reliably unbumped by the time we get here.
	 */
	DUK_ASSERT(heap->pf_prevent_count == 1);
	heap->pf_prevent_count = 0;

#if defined(DUK_USE_DEBUG)
	DUK_DD(DUK_DDPRINT("duk_heap_process_finalize_list: %ld finalizers called", (long) count));
#endif
}

/*
 *  Run an duk_hobject finalizer.  Must never throw an uncaught error
 *  (but may throw caught errors).
 *
 *  There is no return value.  Any return value or error thrown by
 *  the finalizer is ignored (although errors are debug logged).
 *
 *  Notes:
 *
 *    - The finalizer thread 'top' assertions are there because it is
 *      critical that strict stack policy is observed (i.e. no cruft
 *      left on the finalizer stack).
 */

DUK_LOCAL duk_ret_t duk__finalize_helper(duk_hthread *thr, void *udata) {
	DUK_ASSERT(thr != NULL);
	DUK_UNREF(udata);

	DUK_DDD(DUK_DDDPRINT("protected finalization helper running"));

	/* [... obj] */

	/* _Finalizer property is read without checking if the value is
	 * callable or even exists.  This is intentional, and handled
	 * by throwing an error which is caught by the safe call wrapper.
	 *
	 * XXX: Finalizer lookup should traverse the prototype chain (to allow
	 * inherited finalizers) but should not invoke accessors or proxy object
	 * behavior.  At the moment this lookup will invoke proxy behavior, so
	 * caller must ensure that this function is not called if the target is
	 * a Proxy.
	 */
	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_INT_FINALIZER);  /* -> [... obj finalizer] */
	duk_dup_m2(thr);
	duk_push_boolean(thr, DUK_HEAP_HAS_FINALIZER_NORESCUE(thr->heap));
	DUK_DDD(DUK_DDDPRINT("calling finalizer"));
	duk_call(thr, 2);  /* [ ... obj finalizer obj heapDestruct ]  -> [ ... obj retval ] */
	DUK_DDD(DUK_DDDPRINT("finalizer returned successfully"));
	return 0;

	/* Note: we rely on duk_safe_call() to fix up the stack for the caller,
	 * so we don't need to pop stuff here.  There is no return value;
	 * caller determines rescued status based on object refcount.
	 */
}

DUK_INTERNAL void duk_heap_run_finalizer(duk_heap *heap, duk_hobject *obj) {
	duk_hthread *thr;
	duk_ret_t rc;
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t entry_top;
#endif

	DUK_DD(DUK_DDPRINT("running duk_hobject finalizer for object: %p", (void *) obj));

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	thr = heap->heap_thread;
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT_VALSTACK_SPACE(heap->heap_thread, 1);

#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(thr);
#endif
	/*
	 *  Get and call the finalizer.  All of this must be wrapped
	 *  in a protected call, because even getting the finalizer
	 *  may trigger an error (getter may throw one, for instance).
	 */

	/* ROM objects could inherit a finalizer, but they are never deemed
	 * unreachable by mark-and-sweep, and their refcount never falls to 0.
	 */
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));

	/* Duktape 2.1: finalize_list never contains objects with FINALIZED
	 * set, so no need to check here.
	 */
	DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) obj));
#if 0
	if (DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) obj)) {
		DUK_D(DUK_DPRINT("object already finalized, avoid running finalizer twice: %!O", obj));
		return;
	}
#endif
	DUK_HEAPHDR_SET_FINALIZED((duk_heaphdr *) obj);  /* ensure never re-entered until rescue cycle complete */

#if defined(DUK_USE_ES6_PROXY)
	if (DUK_HOBJECT_IS_PROXY(obj)) {
		/* This may happen if duk_set_finalizer() or Duktape.fin() is
		 * called for a Proxy object.  In such cases the fast finalizer
		 * flag will be set on the Proxy, not the target, and neither
		 * will be finalized.
		 */
		DUK_D(DUK_DPRINT("object is a Proxy, skip finalizer call"));
		return;
	}
#endif  /* DUK_USE_ES6_PROXY */

	duk_push_hobject(thr, obj);  /* this also increases refcount by one */
	rc = duk_safe_call(thr, duk__finalize_helper, NULL /*udata*/, 0 /*nargs*/, 1 /*nrets*/);  /* -> [... obj retval/error] */
	DUK_ASSERT_TOP(thr, entry_top + 2);  /* duk_safe_call discipline */

	if (rc != DUK_EXEC_SUCCESS) {
		/* Note: we ask for one return value from duk_safe_call to get this
		 * error debugging here.
		 */
		DUK_D(DUK_DPRINT("wrapped finalizer call failed for object %p (ignored); error: %!T",
		                 (void *) obj, (duk_tval *) duk_get_tval(thr, -1)));
	}
	duk_pop_2(thr);  /* -> [...] */

	DUK_ASSERT_TOP(thr, entry_top);
}

#else  /* DUK_USE_FINALIZER_SUPPORT */

/* nothing */

#endif  /* DUK_USE_FINALIZER_SUPPORT */
/*
 *  String hash computation (interning).
 *
 *  String hashing is performance critical because a string hash is computed
 *  for all new strings which are candidates to be added to the string table.
 *  However, strings actually added to the string table go through a codepoint
 *  length calculation which dominates performance because it goes through
 *  every byte of the input string (but only for strings added).
 *
 *  The string hash algorithm should be fast, but on the other hand provide
 *  good enough hashes to ensure both string table and object property table
 *  hash tables work reasonably well (i.e., there aren't too many collisions
 *  with real world inputs).  Unless the hash is cryptographic, it's always
 *  possible to craft inputs with maximal hash collisions.
 *
 *  NOTE: The hash algorithms must match tools/dukutil.py:duk_heap_hashstring()
 *  for ROM string support!
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_STRHASH_DENSE)
/* Constants for duk_hashstring(). */
#define DUK__STRHASH_SHORTSTRING   4096L
#define DUK__STRHASH_MEDIUMSTRING  (256L * 1024L)
#define DUK__STRHASH_BLOCKSIZE     256L

DUK_INTERNAL duk_uint32_t duk_heap_hashstring(duk_heap *heap, const duk_uint8_t *str, duk_size_t len) {
	duk_uint32_t hash;

	/* Use Murmurhash2 directly for short strings, and use "block skipping"
	 * for long strings: hash an initial part and then sample the rest of
	 * the string with reasonably sized chunks.  An initial offset for the
	 * sampling is computed based on a hash of the initial part of the string;
	 * this is done to (usually) avoid the case where all long strings have
	 * certain offset ranges which are never sampled.
	 *
	 * Skip should depend on length and bound the total time to roughly
	 * logarithmic.  With current values:
	 *
	 *   1M string => 256 * 241 = 61696 bytes (0.06M) of hashing
	 *   1G string => 256 * 16321 = 4178176 bytes (3.98M) of hashing
	 *
	 * XXX: It would be better to compute the skip offset more "smoothly"
	 * instead of having a few boundary values.
	 */

	/* note: mixing len into seed improves hashing when skipping */
	duk_uint32_t str_seed = heap->hash_seed ^ ((duk_uint32_t) len);

	if (len <= DUK__STRHASH_SHORTSTRING) {
		hash = duk_util_hashbytes(str, len, str_seed);
	} else {
		duk_size_t off;
		duk_size_t skip;

		if (len <= DUK__STRHASH_MEDIUMSTRING) {
			skip = (duk_size_t) (16 * DUK__STRHASH_BLOCKSIZE + DUK__STRHASH_BLOCKSIZE);
		} else {
			skip = (duk_size_t) (256 * DUK__STRHASH_BLOCKSIZE + DUK__STRHASH_BLOCKSIZE);
		}

		hash = duk_util_hashbytes(str, (duk_size_t) DUK__STRHASH_SHORTSTRING, str_seed);
		off = DUK__STRHASH_SHORTSTRING + (skip * (hash % 256)) / 256;

		/* XXX: inefficient loop */
		while (off < len) {
			duk_size_t left = len - off;
			duk_size_t now = (duk_size_t) (left > DUK__STRHASH_BLOCKSIZE ? DUK__STRHASH_BLOCKSIZE : left);
			hash ^= duk_util_hashbytes(str + off, now, str_seed);
			off += skip;
		}
	}

#if defined(DUK_USE_STRHASH16)
	/* Truncate to 16 bits here, so that a computed hash can be compared
	 * against a hash stored in a 16-bit field.
	 */
	hash &= 0x0000ffffUL;
#endif
	return hash;
}
#else  /* DUK_USE_STRHASH_DENSE */
DUK_INTERNAL duk_uint32_t duk_heap_hashstring(duk_heap *heap, const duk_uint8_t *str, duk_size_t len) {
	duk_uint32_t hash;
	duk_size_t step;
	duk_size_t off;

	/* Slightly modified "Bernstein hash" from:
	 *
	 *     http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
	 *
	 * Modifications: string skipping and reverse direction similar to
	 * Lua 5.1.5, and different hash initializer.
	 *
	 * The reverse direction ensures last byte it always included in the
	 * hash which is a good default as changing parts of the string are
	 * more often in the suffix than in the prefix.
	 */

	hash = heap->hash_seed ^ ((duk_uint32_t) len);  /* Bernstein hash init value is normally 5381 */
	step = (len >> DUK_USE_STRHASH_SKIP_SHIFT) + 1;
	for (off = len; off >= step; off -= step) {
		DUK_ASSERT(off >= 1);  /* off >= step, and step >= 1 */
		hash = (hash * 33) + str[off - 1];
	}

#if defined(DUK_USE_STRHASH16)
	/* Truncate to 16 bits here, so that a computed hash can be compared
	 * against a hash stored in a 16-bit field.
	 */
	hash &= 0x0000ffffUL;
#endif
	return hash;
}
#endif  /* DUK_USE_STRHASH_DENSE */

/* automatic undefs */
#undef DUK__STRHASH_BLOCKSIZE
#undef DUK__STRHASH_MEDIUMSTRING
#undef DUK__STRHASH_SHORTSTRING
/*
 *  Mark-and-sweep garbage collection.
 */

/* #include duk_internal.h -> already included */

DUK_LOCAL_DECL void duk__mark_heaphdr(duk_heap *heap, duk_heaphdr *h);
DUK_LOCAL_DECL void duk__mark_heaphdr_nonnull(duk_heap *heap, duk_heaphdr *h);
DUK_LOCAL_DECL void duk__mark_tval(duk_heap *heap, duk_tval *tv);
DUK_LOCAL_DECL void duk__mark_tvals(duk_heap *heap, duk_tval *tv, duk_idx_t count);

/*
 *  Marking functions for heap types: mark children recursively.
 */

DUK_LOCAL void duk__mark_hstring(duk_heap *heap, duk_hstring *h) {
	DUK_UNREF(heap);
	DUK_UNREF(h);

	DUK_DDD(DUK_DDDPRINT("duk__mark_hstring: %p", (void *) h));
	DUK_ASSERT(h);
	DUK_HSTRING_ASSERT_VALID(h);

	/* nothing to process */
}

DUK_LOCAL void duk__mark_hobject(duk_heap *heap, duk_hobject *h) {
	duk_uint_fast32_t i;

	DUK_DDD(DUK_DDDPRINT("duk__mark_hobject: %p", (void *) h));

	DUK_ASSERT(h);
	DUK_HOBJECT_ASSERT_VALID(h);

	/* XXX: use advancing pointers instead of index macros -> faster and smaller? */

	for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
		duk_hstring *key = DUK_HOBJECT_E_GET_KEY(heap, h, i);
		if (key == NULL) {
			continue;
		}
		duk__mark_heaphdr_nonnull(heap, (duk_heaphdr *) key);
		if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(heap, h, i)) {
			duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->a.get);
			duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->a.set);
		} else {
			duk__mark_tval(heap, &DUK_HOBJECT_E_GET_VALUE_PTR(heap, h, i)->v);
		}
	}

	for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(h); i++) {
		duk__mark_tval(heap, DUK_HOBJECT_A_GET_VALUE_PTR(heap, h, i));
	}

	/* Hash part is a 'weak reference' and does not contribute. */

	duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HOBJECT_GET_PROTOTYPE(heap, h));

	/* Fast path for objects which don't have a subclass struct, or have a
	 * subclass struct but nothing that needs marking in the subclass struct.
	 */
	if (DUK_HOBJECT_HAS_FASTREFS(h)) {
		DUK_ASSERT(DUK_HOBJECT_ALLOWS_FASTREFS(h));
		return;
	}
	DUK_ASSERT(DUK_HOBJECT_PROHIBITS_FASTREFS(h));

	/* XXX: reorg, more common first */
	if (DUK_HOBJECT_IS_COMPFUNC(h)) {
		duk_hcompfunc *f = (duk_hcompfunc *) h;
		duk_tval *tv, *tv_end;
		duk_hobject **fn, **fn_end;

		DUK_HCOMPFUNC_ASSERT_VALID(f);

		/* 'data' is reachable through every compiled function which
		 * contains a reference.
		 */

		duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HCOMPFUNC_GET_DATA(heap, f));
		duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HCOMPFUNC_GET_LEXENV(heap, f));
		duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_HCOMPFUNC_GET_VARENV(heap, f));

		if (DUK_HCOMPFUNC_GET_DATA(heap, f) != NULL) {
			tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(heap, f);
			tv_end = DUK_HCOMPFUNC_GET_CONSTS_END(heap, f);
			while (tv < tv_end) {
				duk__mark_tval(heap, tv);
				tv++;
			}

			fn = DUK_HCOMPFUNC_GET_FUNCS_BASE(heap, f);
			fn_end = DUK_HCOMPFUNC_GET_FUNCS_END(heap, f);
			while (fn < fn_end) {
				duk__mark_heaphdr_nonnull(heap, (duk_heaphdr *) *fn);
				fn++;
			}
		} else {
			/* May happen in some out-of-memory corner cases. */
			DUK_D(DUK_DPRINT("duk_hcompfunc 'data' is NULL, skipping marking"));
		}
	} else if (DUK_HOBJECT_IS_DECENV(h)) {
		duk_hdecenv *e = (duk_hdecenv *) h;
		DUK_HDECENV_ASSERT_VALID(e);
		duk__mark_heaphdr(heap, (duk_heaphdr *) e->thread);
		duk__mark_heaphdr(heap, (duk_heaphdr *) e->varmap);
	} else if (DUK_HOBJECT_IS_OBJENV(h)) {
		duk_hobjenv *e = (duk_hobjenv *) h;
		DUK_HOBJENV_ASSERT_VALID(e);
		duk__mark_heaphdr_nonnull(heap, (duk_heaphdr *) e->target);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	} else if (DUK_HOBJECT_IS_BUFOBJ(h)) {
		duk_hbufobj *b = (duk_hbufobj *) h;
		DUK_HBUFOBJ_ASSERT_VALID(b);
		duk__mark_heaphdr(heap, (duk_heaphdr *) b->buf);
		duk__mark_heaphdr(heap, (duk_heaphdr *) b->buf_prop);
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
	} else if (DUK_HOBJECT_IS_BOUNDFUNC(h)) {
		duk_hboundfunc *f = (duk_hboundfunc *) (void *) h;
		DUK_HBOUNDFUNC_ASSERT_VALID(f);
		duk__mark_tval(heap, &f->target);
		duk__mark_tval(heap, &f->this_binding);
		duk__mark_tvals(heap, f->args, f->nargs);
#if defined(DUK_USE_ES6_PROXY)
	} else if (DUK_HOBJECT_IS_PROXY(h)) {
		duk_hproxy *p = (duk_hproxy *) h;
		DUK_HPROXY_ASSERT_VALID(p);
		duk__mark_heaphdr_nonnull(heap, (duk_heaphdr *) p->target);
		duk__mark_heaphdr_nonnull(heap, (duk_heaphdr *) p->handler);
#endif  /* DUK_USE_ES6_PROXY */
	} else if (DUK_HOBJECT_IS_THREAD(h)) {
		duk_hthread *t = (duk_hthread *) h;
		duk_activation *act;
		duk_tval *tv;

		DUK_HTHREAD_ASSERT_VALID(t);

		tv = t->valstack;
		while (tv < t->valstack_top) {
			duk__mark_tval(heap, tv);
			tv++;
		}

		for (act = t->callstack_curr; act != NULL; act = act->parent) {
			duk__mark_heaphdr(heap, (duk_heaphdr *) DUK_ACT_GET_FUNC(act));
			duk__mark_heaphdr(heap, (duk_heaphdr *) act->var_env);
			duk__mark_heaphdr(heap, (duk_heaphdr *) act->lex_env);
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
			duk__mark_heaphdr(heap, (duk_heaphdr *) act->prev_caller);
#endif
#if 0  /* nothing now */
			for (cat = act->cat; cat != NULL; cat = cat->parent) {
			}
#endif
		}

		duk__mark_heaphdr(heap, (duk_heaphdr *) t->resumer);

		for (i = 0; i < DUK_NUM_BUILTINS; i++) {
			duk__mark_heaphdr(heap, (duk_heaphdr *) t->builtins[i]);
		}
	} else {
		/* We may come here if the object should have a FASTREFS flag
		 * but it's missing for some reason.  Assert for never getting
		 * here; however, other than performance, this is harmless.
		 */
		DUK_D(DUK_DPRINT("missing FASTREFS flag for: %!iO", h));
		DUK_ASSERT(0);
	}
}

/* Mark any duk_heaphdr type.  Recursion tracking happens only here. */
DUK_LOCAL void duk__mark_heaphdr(duk_heap *heap, duk_heaphdr *h) {
	DUK_DDD(DUK_DDDPRINT("duk__mark_heaphdr %p, type %ld",
	                     (void *) h,
	                     (h != NULL ? (long) DUK_HEAPHDR_GET_TYPE(h) : (long) -1)));

	/* XXX: add non-null variant? */
	if (h == NULL) {
		return;
	}

	DUK_HEAPHDR_ASSERT_VALID(h);
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(h) || DUK_HEAPHDR_HAS_REACHABLE(h));

#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_REFERENCE_COUNTING)
	if (!DUK_HEAPHDR_HAS_READONLY(h)) {
		h->h_assert_refcount++;  /* Comparison refcount: bump even if already reachable. */
	}
#endif
	if (DUK_HEAPHDR_HAS_REACHABLE(h)) {
		DUK_DDD(DUK_DDDPRINT("already marked reachable, skip"));
		return;
	}
#if defined(DUK_USE_ROM_OBJECTS)
	/* READONLY objects always have REACHABLE set, so the check above
	 * will prevent READONLY objects from being marked here.
	 */
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(h));
#endif

	DUK_HEAPHDR_SET_REACHABLE(h);

	if (heap->ms_recursion_depth >= DUK_USE_MARK_AND_SWEEP_RECLIMIT) {
		DUK_D(DUK_DPRINT("mark-and-sweep recursion limit reached, marking as temproot: %p", (void *) h));
		DUK_HEAP_SET_MARKANDSWEEP_RECLIMIT_REACHED(heap);
		DUK_HEAPHDR_SET_TEMPROOT(h);
		return;
	}

	heap->ms_recursion_depth++;
	DUK_ASSERT(heap->ms_recursion_depth != 0);  /* Wrap. */

	switch (DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING:
		duk__mark_hstring(heap, (duk_hstring *) h);
		break;
	case DUK_HTYPE_OBJECT:
		duk__mark_hobject(heap, (duk_hobject *) h);
		break;
	case DUK_HTYPE_BUFFER:
		/* nothing to mark */
		break;
	default:
		DUK_D(DUK_DPRINT("attempt to mark heaphdr %p with invalid htype %ld", (void *) h, (long) DUK_HEAPHDR_GET_TYPE(h)));
		DUK_UNREACHABLE();
	}

	DUK_ASSERT(heap->ms_recursion_depth > 0);
	heap->ms_recursion_depth--;
}

DUK_LOCAL void duk__mark_tval(duk_heap *heap, duk_tval *tv) {
	DUK_DDD(DUK_DDDPRINT("duk__mark_tval %p", (void *) tv));
	if (tv == NULL) {
		return;
	}
	DUK_TVAL_ASSERT_VALID(tv);
	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		duk_heaphdr *h;
		h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		duk__mark_heaphdr_nonnull(heap, h);
	}
}

DUK_LOCAL void duk__mark_tvals(duk_heap *heap, duk_tval *tv, duk_idx_t count) {
	DUK_ASSERT(count == 0 || tv != NULL);

	while (count-- > 0) {
		DUK_TVAL_ASSERT_VALID(tv);
		if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
			duk_heaphdr *h;
			h = DUK_TVAL_GET_HEAPHDR(tv);
			DUK_ASSERT(h != NULL);
			duk__mark_heaphdr_nonnull(heap, h);
		}
		tv++;
	}
}

/* Mark any duk_heaphdr type, caller guarantees a non-NULL pointer. */
DUK_LOCAL void duk__mark_heaphdr_nonnull(duk_heap *heap, duk_heaphdr *h) {
	/* For now, just call the generic handler.  Change when call sites
	 * are changed too.
	 */
	duk__mark_heaphdr(heap, h);
}

/*
 *  Mark the heap.
 */

DUK_LOCAL void duk__mark_roots_heap(duk_heap *heap) {
	duk_small_uint_t i;

	DUK_DD(DUK_DDPRINT("duk__mark_roots_heap: %p", (void *) heap));

	duk__mark_heaphdr(heap, (duk_heaphdr *) heap->heap_thread);
	duk__mark_heaphdr(heap, (duk_heaphdr *) heap->heap_object);

	for (i = 0; i < DUK_HEAP_NUM_STRINGS; i++) {
		duk_hstring *h = DUK_HEAP_GET_STRING(heap, i);
		duk__mark_heaphdr(heap, (duk_heaphdr *) h);
	}

	duk__mark_tval(heap, &heap->lj.value1);
	duk__mark_tval(heap, &heap->lj.value2);

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	for (i = 0; i < heap->dbg_breakpoint_count; i++) {
		duk__mark_heaphdr(heap, (duk_heaphdr *) heap->dbg_breakpoints[i].filename);
	}
#endif
}

/*
 *  Mark unreachable, finalizable objects.
 *
 *  Such objects will be moved aside and their finalizers run later.  They
 *  have to be treated as reachability roots for their properties etc to
 *  remain allocated.  This marking is only done for unreachable values which
 *  would be swept later.
 *
 *  Objects are first marked FINALIZABLE and only then marked as reachability
 *  roots; otherwise circular references might be handled inconsistently.
 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_LOCAL void duk__mark_finalizable(duk_heap *heap) {
	duk_heaphdr *hdr;
	duk_size_t count_finalizable = 0;

	DUK_DD(DUK_DDPRINT("duk__mark_finalizable: %p", (void *) heap));

	DUK_ASSERT(heap->heap_thread != NULL);

	hdr = heap->heap_allocated;
	while (hdr != NULL) {
		/* A finalizer is looked up from the object and up its
		 * prototype chain (which allows inherited finalizers).
		 * The finalizer is checked for using a duk_hobject flag
		 * which is kept in sync with the presence and callability
		 * of a _Finalizer hidden symbol.
		 */

		if (!DUK_HEAPHDR_HAS_REACHABLE(hdr) &&
		    DUK_HEAPHDR_IS_OBJECT(hdr) &&
		    !DUK_HEAPHDR_HAS_FINALIZED(hdr) &&
		    DUK_HOBJECT_HAS_FINALIZER_FAST(heap, (duk_hobject *) hdr)) {
			/* heaphdr:
			 *  - is not reachable
			 *  - is an object
			 *  - is not a finalized object waiting for rescue/keep decision
			 *  - has a finalizer
			 */

			DUK_DD(DUK_DDPRINT("unreachable heap object will be "
			                   "finalized -> mark as finalizable "
			                   "and treat as a reachability root: %p",
			                   (void *) hdr));
			DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(hdr));
			DUK_HEAPHDR_SET_FINALIZABLE(hdr);
			count_finalizable++;
		}

		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}

	if (count_finalizable == 0) {
		return;
	}

	DUK_DD(DUK_DDPRINT("marked %ld heap objects as finalizable, now mark them reachable",
	                   (long) count_finalizable));

	hdr = heap->heap_allocated;
	while (hdr != NULL) {
		if (DUK_HEAPHDR_HAS_FINALIZABLE(hdr)) {
			duk__mark_heaphdr_nonnull(heap, hdr);
		}

		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}

	/* Caller will finish the marking process if we hit a recursion limit. */
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

/*
 *  Mark objects on finalize_list.
 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_LOCAL void duk__mark_finalize_list(duk_heap *heap) {
	duk_heaphdr *hdr;
#if defined(DUK_USE_DEBUG)
	duk_size_t count_finalize_list = 0;
#endif

	DUK_DD(DUK_DDPRINT("duk__mark_finalize_list: %p", (void *) heap));

	hdr = heap->finalize_list;
	while (hdr != NULL) {
		duk__mark_heaphdr_nonnull(heap, hdr);
		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
#if defined(DUK_USE_DEBUG)
		count_finalize_list++;
#endif
	}

#if defined(DUK_USE_DEBUG)
	if (count_finalize_list > 0) {
		DUK_D(DUK_DPRINT("marked %ld objects on the finalize_list as reachable (previous finalizer run skipped)",
		                 (long) count_finalize_list));
	}
#endif
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

/*
 *  Fallback marking handler if recursion limit is reached.
 *
 *  Iterates 'temproots' until recursion limit is no longer hit.  Temproots
 *  can be in heap_allocated or finalize_list; refzero_list is now always
 *  empty for mark-and-sweep.  A temproot may occur in finalize_list now if
 *  there are objects on the finalize_list and user code creates a reference
 *  from an object in heap_allocated to the object in finalize_list (which is
 *  now allowed), and it happened to coincide with the recursion depth limit.
 *
 *  This is a slow scan, but guarantees that we finish with a bounded C stack.
 *
 *  Note that nodes may have been marked as temproots before this scan begun,
 *  OR they may have been marked during the scan (as we process nodes
 *  recursively also during the scan).  This is intended behavior.
 */

#if defined(DUK_USE_DEBUG)
DUK_LOCAL void duk__handle_temproot(duk_heap *heap, duk_heaphdr *hdr, duk_size_t *count) {
#else
DUK_LOCAL void duk__handle_temproot(duk_heap *heap, duk_heaphdr *hdr) {
#endif
	DUK_ASSERT(hdr != NULL);

	if (!DUK_HEAPHDR_HAS_TEMPROOT(hdr)) {
		DUK_DDD(DUK_DDDPRINT("not a temp root: %p", (void *) hdr));
		return;
	}

	DUK_DDD(DUK_DDDPRINT("found a temp root: %p", (void *) hdr));
	DUK_HEAPHDR_CLEAR_TEMPROOT(hdr);
	DUK_HEAPHDR_CLEAR_REACHABLE(hdr);  /* Done so that duk__mark_heaphdr() works correctly. */
#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_REFERENCE_COUNTING)
	hdr->h_assert_refcount--;  /* Same node visited twice. */
#endif
	duk__mark_heaphdr_nonnull(heap, hdr);

#if defined(DUK_USE_DEBUG)
	(*count)++;
#endif
}

DUK_LOCAL void duk__mark_temproots_by_heap_scan(duk_heap *heap) {
	duk_heaphdr *hdr;
#if defined(DUK_USE_DEBUG)
	duk_size_t count;
#endif

	DUK_DD(DUK_DDPRINT("duk__mark_temproots_by_heap_scan: %p", (void *) heap));

	while (DUK_HEAP_HAS_MARKANDSWEEP_RECLIMIT_REACHED(heap)) {
		DUK_DD(DUK_DDPRINT("recursion limit reached, doing heap scan to continue from temproots"));

#if defined(DUK_USE_DEBUG)
		count = 0;
#endif
		DUK_HEAP_CLEAR_MARKANDSWEEP_RECLIMIT_REACHED(heap);

		hdr = heap->heap_allocated;
		while (hdr) {
#if defined(DUK_USE_DEBUG)
			duk__handle_temproot(heap, hdr, &count);
#else
			duk__handle_temproot(heap, hdr);
#endif
			hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
		}

#if defined(DUK_USE_FINALIZER_SUPPORT)
		hdr = heap->finalize_list;
		while (hdr) {
#if defined(DUK_USE_DEBUG)
			duk__handle_temproot(heap, hdr, &count);
#else
			duk__handle_temproot(heap, hdr);
#endif
			hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
		}
#endif

#if defined(DUK_USE_DEBUG)
		DUK_DD(DUK_DDPRINT("temproot mark heap scan processed %ld temp roots", (long) count));
#endif
	}
}

/*
 *  Finalize refcounts for heap elements just about to be freed.
 *  This must be done for all objects before freeing to avoid any
 *  stale pointer dereferences.
 *
 *  Note that this must deduce the set of objects to be freed
 *  identically to duk__sweep_heap().
 */

#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_LOCAL void duk__finalize_refcounts(duk_heap *heap) {
	duk_heaphdr *hdr;

	DUK_ASSERT(heap->heap_thread != NULL);

	DUK_DD(DUK_DDPRINT("duk__finalize_refcounts: heap=%p", (void *) heap));

	hdr = heap->heap_allocated;
	while (hdr) {
		if (!DUK_HEAPHDR_HAS_REACHABLE(hdr)) {
			/*
			 *  Unreachable object about to be swept.  Finalize target refcounts
			 *  (objects which the unreachable object points to) without doing
			 *  refzero processing.  Recursive decrefs are also prevented when
			 *  refzero processing is disabled.
			 *
			 *  Value cannot be a finalizable object, as they have been made
			 *  temporarily reachable for this round.
			 */

			DUK_DDD(DUK_DDDPRINT("unreachable object, refcount finalize before sweeping: %p", (void *) hdr));

			/* Finalize using heap->heap_thread; DECREF has a
			 * suppress check for mark-and-sweep which is based
			 * on heap->ms_running.
			 */
			duk_heaphdr_refcount_finalize_norz(heap, hdr);
		}

		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}
}
#endif  /* DUK_USE_REFERENCE_COUNTING */

/*
 *  Clear (reachable) flags of finalize_list.
 *
 *  We could mostly do in the sweep phase when we move objects from the
 *  heap into the finalize_list.  However, if a finalizer run is skipped
 *  during a mark-and-sweep, the objects on the finalize_list will be marked
 *  reachable during the next mark-and-sweep.  Since they're already on the
 *  finalize_list, no-one will be clearing their REACHABLE flag so we do it
 *  here.  (This now overlaps with the sweep handling in a harmless way.)
 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_LOCAL void duk__clear_finalize_list_flags(duk_heap *heap) {
	duk_heaphdr *hdr;

	DUK_DD(DUK_DDPRINT("duk__clear_finalize_list_flags: %p", (void *) heap));

	hdr = heap->finalize_list;
	while (hdr) {
		DUK_HEAPHDR_CLEAR_REACHABLE(hdr);
#if defined(DUK_USE_ASSERTIONS)
		DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZABLE(hdr) || \
		           (heap->currently_finalizing == hdr));
#endif
		/* DUK_HEAPHDR_FLAG_FINALIZED may be set. */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(hdr));
		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

/*
 *  Sweep stringtable.
 */

DUK_LOCAL void duk__sweep_stringtable(duk_heap *heap, duk_size_t *out_count_keep) {
	duk_hstring *h;
	duk_hstring *prev;
	duk_uint32_t i;
#if defined(DUK_USE_DEBUG)
	duk_size_t count_free = 0;
#endif
	duk_size_t count_keep = 0;

	DUK_DD(DUK_DDPRINT("duk__sweep_stringtable: %p", (void *) heap));

#if defined(DUK_USE_STRTAB_PTRCOMP)
	if (heap->strtable16 == NULL) {
#else
	if (heap->strtable == NULL) {
#endif
		goto done;
	}

	for (i = 0; i < heap->st_size; i++) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
		h = DUK_USE_HEAPPTR_DEC16(heap->heap_udata, heap->strtable16[i]);
#else
		h = heap->strtable[i];
#endif
		prev = NULL;
		while (h != NULL) {
			duk_hstring *next;
			next = h->hdr.h_next;

			if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h))
			{
				DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
				count_keep++;
				prev = h;
			} else {
#if defined(DUK_USE_DEBUG)
				count_free++;
#endif

				/* For pinned strings the refcount has been
				 * bumped.  We could unbump it here before
				 * freeing, but that's actually not necessary
				 * except for assertions.
				 */
#if 0
				if (DUK_HSTRING_HAS_PINNED_LITERAL(h)) {
					DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) > 0U);
					DUK_HSTRING_DECREF_NORZ(heap->heap_thread, h);
					DUK_HSTRING_CLEAR_PINNED_LITERAL(h);
				}
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
				/* Non-zero refcounts should not happen for unreachable strings,
				 * because we refcount finalize all unreachable objects which
				 * should have decreased unreachable string refcounts to zero
				 * (even for cycles).  However, pinned strings have a +1 bump.
				 */
				DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) ==
				           DUK_HSTRING_HAS_PINNED_LITERAL(h) ? 1U : 0U);
#endif

				/* Deal with weak references first. */
				duk_heap_strcache_string_remove(heap, (duk_hstring *) h);

				/* Remove the string from the string table. */
				duk_heap_strtable_unlink_prev(heap, (duk_hstring *) h, (duk_hstring *) prev);

				/* Free inner references (these exist e.g. when external
				 * strings are enabled) and the struct itself.
				 */
				duk_free_hstring(heap, (duk_hstring *) h);

				/* Don't update 'prev'; it should be last string kept. */
			}

			h = next;
		}
	}

 done:
#if defined(DUK_USE_DEBUG)
	DUK_D(DUK_DPRINT("mark-and-sweep sweep stringtable: %ld freed, %ld kept",
	                 (long) count_free, (long) count_keep));
#endif
	*out_count_keep = count_keep;
}

/*
 *  Sweep heap.
 */

DUK_LOCAL void duk__sweep_heap(duk_heap *heap, duk_small_uint_t flags, duk_size_t *out_count_keep) {
	duk_heaphdr *prev;  /* last element that was left in the heap */
	duk_heaphdr *curr;
	duk_heaphdr *next;
#if defined(DUK_USE_DEBUG)
	duk_size_t count_free = 0;
	duk_size_t count_finalize = 0;
	duk_size_t count_rescue = 0;
#endif
	duk_size_t count_keep = 0;

	DUK_DD(DUK_DDPRINT("duk__sweep_heap: %p", (void *) heap));

	prev = NULL;
	curr = heap->heap_allocated;
	heap->heap_allocated = NULL;
	while (curr) {
		/* Strings and ROM objects are never placed on the heap allocated list. */
		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) != DUK_HTYPE_STRING);
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(curr));

		next = DUK_HEAPHDR_GET_NEXT(heap, curr);

		if (DUK_HEAPHDR_HAS_REACHABLE(curr)) {
			/*
			 *  Reachable object:
			 *    - If FINALIZABLE -> actually unreachable (but marked
			 *      artificially reachable), queue to finalize_list.
			 *    - If !FINALIZABLE but FINALIZED -> rescued after
			 *      finalizer execution.
			 *    - Otherwise just a normal, reachable object.
			 *
			 *  Objects which are kept are queued to heap_allocated
			 *  tail (we're essentially filtering heap_allocated in
			 *  practice).
			 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
			if (DUK_UNLIKELY(DUK_HEAPHDR_HAS_FINALIZABLE(curr))) {
				DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
				DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);
				DUK_DD(DUK_DDPRINT("sweep; reachable, finalizable --> move to finalize_list: %p", (void *) curr));

#if defined(DUK_USE_REFERENCE_COUNTING)
				DUK_HEAPHDR_PREINC_REFCOUNT(curr);  /* Bump refcount so that refzero never occurs when pending a finalizer call. */
#endif
				DUK_HEAP_INSERT_INTO_FINALIZE_LIST(heap, curr);
#if defined(DUK_USE_DEBUG)
				count_finalize++;
#endif
			}
			else
#endif  /* DUK_USE_FINALIZER_SUPPORT */
			{
				if (DUK_UNLIKELY(DUK_HEAPHDR_HAS_FINALIZED(curr))) {
					DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
					DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);

					if (flags & DUK_MS_FLAG_POSTPONE_RESCUE) {
						DUK_DD(DUK_DDPRINT("sweep; reachable, finalized, but postponing rescue decisions --> keep object (with FINALIZED set): %!iO", curr));
						count_keep++;
					} else {
						DUK_DD(DUK_DDPRINT("sweep; reachable, finalized --> rescued after finalization: %p", (void *) curr));
#if defined(DUK_USE_FINALIZER_SUPPORT)
						DUK_HEAPHDR_CLEAR_FINALIZED(curr);
#endif
#if defined(DUK_USE_DEBUG)
						count_rescue++;
#endif
					}
				} else {
					DUK_DD(DUK_DDPRINT("sweep; reachable --> keep: %!iO", curr));
					count_keep++;
				}

				if (prev != NULL) {
					DUK_ASSERT(heap->heap_allocated != NULL);
					DUK_HEAPHDR_SET_NEXT(heap, prev, curr);
				} else {
					DUK_ASSERT(heap->heap_allocated == NULL);
					heap->heap_allocated = curr;
				}
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
				DUK_HEAPHDR_SET_PREV(heap, curr, prev);
#endif
				DUK_HEAPHDR_ASSERT_LINKS(heap, prev);
				DUK_HEAPHDR_ASSERT_LINKS(heap, curr);
				prev = curr;
			}

			/*
			 *  Shrink check for value stacks here.  We're inside
			 *  ms_prevent_count protection which prevents recursive
			 *  mark-and-sweep and refzero finalizers, so there are
			 *  no side effects that would affect the heap lists.
			 */
			if (DUK_HEAPHDR_IS_OBJECT(curr) && DUK_HOBJECT_IS_THREAD((duk_hobject *) curr)) {
				duk_hthread *thr_curr = (duk_hthread *) curr;
				DUK_DD(DUK_DDPRINT("value stack shrink check for thread: %!O", curr));
				duk_valstack_shrink_check_nothrow(thr_curr, flags & DUK_MS_FLAG_EMERGENCY /*snug*/);
			}

			DUK_HEAPHDR_CLEAR_REACHABLE(curr);
			/* Keep FINALIZED if set, used if rescue decisions are postponed. */
			/* Keep FINALIZABLE for objects on finalize_list. */
			DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr));
		} else {
			/*
			 *  Unreachable object:
			 *    - If FINALIZED, object was finalized but not
			 *      rescued.  This doesn't affect freeing.
			 *    - Otherwise normal unreachable object.
			 *
			 *  There's no guard preventing a FINALIZED object
			 *  from being freed while finalizers execute: the
			 *  artificial finalize_list reachability roots can't
			 *  cause an incorrect free decision (but can cause
			 *  an incorrect rescue decision).
			 */

#if defined(DUK_USE_REFERENCE_COUNTING)
			/* Non-zero refcounts should not happen because we refcount
			 * finalize all unreachable objects which should cancel out
			 * refcounts (even for cycles).
			 */
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) == 0);
#endif
			DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));

#if defined(DUK_USE_DEBUG)
			if (DUK_HEAPHDR_HAS_FINALIZED(curr)) {
				DUK_DD(DUK_DDPRINT("sweep; unreachable, finalized --> finalized object not rescued: %p", (void *) curr));
			} else {
				DUK_DD(DUK_DDPRINT("sweep; not reachable --> free: %p", (void *) curr));
			}

#endif

			/* Note: object cannot be a finalizable unreachable object, as
			 * they have been marked temporarily reachable for this round,
			 * and are handled above.
			 */

#if defined(DUK_USE_DEBUG)
			count_free++;
#endif

			/* Weak refs should be handled here, but no weak refs for
			 * any non-string objects exist right now.
			 */

			/* Free object and all auxiliary (non-heap) allocs. */
			duk_heap_free_heaphdr_raw(heap, curr);
		}

		curr = next;
	}

	if (prev != NULL) {
		DUK_HEAPHDR_SET_NEXT(heap, prev, NULL);
	}
	DUK_HEAPHDR_ASSERT_LINKS(heap, prev);

#if defined(DUK_USE_DEBUG)
	DUK_D(DUK_DPRINT("mark-and-sweep sweep objects (non-string): %ld freed, %ld kept, %ld rescued, %ld queued for finalization",
	                 (long) count_free, (long) count_keep, (long) count_rescue, (long) count_finalize));
#endif
	*out_count_keep = count_keep;
}

/*
 *  Litcache helpers.
 */

#if defined(DUK_USE_LITCACHE_SIZE)
DUK_LOCAL void duk__wipe_litcache(duk_heap *heap) {
	duk_uint_t i;
	duk_litcache_entry *e;

	e = heap->litcache;
	for (i = 0; i < DUK_USE_LITCACHE_SIZE; i++) {
		e->addr = NULL;
		/* e->h does not need to be invalidated: when e->addr is
		 * NULL, e->h is considered garbage.
		 */
		e++;
	}
}
#endif  /* DUK_USE_LITCACHE_SIZE */

/*
 *  Object compaction.
 *
 *  Compaction is assumed to never throw an error.
 */

DUK_LOCAL int duk__protected_compact_object(duk_hthread *thr, void *udata) {
	duk_hobject *obj;
	/* XXX: for threads, compact stacks? */

	DUK_UNREF(udata);
	obj = duk_known_hobject(thr, -1);
	duk_hobject_compact_props(thr, obj);
	return 0;
}

#if defined(DUK_USE_DEBUG)
DUK_LOCAL void duk__compact_object_list(duk_heap *heap, duk_hthread *thr, duk_heaphdr *start, duk_size_t *p_count_check, duk_size_t *p_count_compact, duk_size_t *p_count_bytes_saved) {
#else
DUK_LOCAL void duk__compact_object_list(duk_heap *heap, duk_hthread *thr, duk_heaphdr *start) {
#endif
	duk_heaphdr *curr;
#if defined(DUK_USE_DEBUG)
	duk_size_t old_size, new_size;
#endif
	duk_hobject *obj;

	DUK_UNREF(heap);

	curr = start;
	while (curr) {
		DUK_DDD(DUK_DDDPRINT("mark-and-sweep compact: %p", (void *) curr));

		if (DUK_HEAPHDR_GET_TYPE(curr) != DUK_HTYPE_OBJECT) {
			goto next;
		}
		obj = (duk_hobject *) curr;

#if defined(DUK_USE_DEBUG)
		old_size = DUK_HOBJECT_P_COMPUTE_SIZE(DUK_HOBJECT_GET_ESIZE(obj),
		                                      DUK_HOBJECT_GET_ASIZE(obj),
		                                      DUK_HOBJECT_GET_HSIZE(obj));
#endif

		DUK_DD(DUK_DDPRINT("compact object: %p", (void *) obj));
		duk_push_hobject(thr, obj);
		/* XXX: disable error handlers for duration of compaction? */
		duk_safe_call(thr, duk__protected_compact_object, NULL, 1, 0);

#if defined(DUK_USE_DEBUG)
		new_size = DUK_HOBJECT_P_COMPUTE_SIZE(DUK_HOBJECT_GET_ESIZE(obj),
		                                      DUK_HOBJECT_GET_ASIZE(obj),
		                                      DUK_HOBJECT_GET_HSIZE(obj));
#endif

#if defined(DUK_USE_DEBUG)
		(*p_count_compact)++;
		(*p_count_bytes_saved) += (duk_size_t) (old_size - new_size);
#endif

	 next:
		curr = DUK_HEAPHDR_GET_NEXT(heap, curr);
#if defined(DUK_USE_DEBUG)
		(*p_count_check)++;
#endif
	}
}

DUK_LOCAL void duk__compact_objects(duk_heap *heap) {
	/* XXX: which lists should participate?  to be finalized? */
#if defined(DUK_USE_DEBUG)
	duk_size_t count_check = 0;
	duk_size_t count_compact = 0;
	duk_size_t count_bytes_saved = 0;
#endif

	DUK_DD(DUK_DDPRINT("duk__compact_objects: %p", (void *) heap));

	DUK_ASSERT(heap->heap_thread != NULL);

#if defined(DUK_USE_DEBUG)
	duk__compact_object_list(heap, heap->heap_thread, heap->heap_allocated, &count_check, &count_compact, &count_bytes_saved);
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__compact_object_list(heap, heap->heap_thread, heap->finalize_list, &count_check, &count_compact, &count_bytes_saved);
#endif
#else
	duk__compact_object_list(heap, heap->heap_thread, heap->heap_allocated);
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__compact_object_list(heap, heap->heap_thread, heap->finalize_list);
#endif
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);  /* Always handled to completion inline in DECREF. */
#endif

#if defined(DUK_USE_DEBUG)
	DUK_D(DUK_DPRINT("mark-and-sweep compact objects: %ld checked, %ld compaction attempts, %ld bytes saved by compaction",
	                 (long) count_check, (long) count_compact, (long) count_bytes_saved));
#endif
}

/*
 *  Assertion helpers.
 */

#if defined(DUK_USE_ASSERTIONS)
typedef void (*duk__gc_heaphdr_assert)(duk_heap *heap, duk_heaphdr *h);
typedef void (*duk__gc_hstring_assert)(duk_heap *heap, duk_hstring *h);

DUK_LOCAL void duk__assert_walk_list(duk_heap *heap, duk_heaphdr *start, duk__gc_heaphdr_assert func) {
	duk_heaphdr *curr;
	for (curr = start; curr != NULL; curr = DUK_HEAPHDR_GET_NEXT(heap, curr)) {
		func(heap, curr);
	}
}

DUK_LOCAL void duk__assert_walk_strtable(duk_heap *heap, duk__gc_hstring_assert func) {
	duk_uint32_t i;

	for (i = 0; i < heap->st_size; i++) {
		duk_hstring *h;

#if defined(DUK_USE_STRTAB_PTRCOMP)
		h = DUK_USE_HEAPPTR_DEC16(heap->heap_udata, heap->strtable16[i]);
#else
		h = heap->strtable[i];
#endif
		while (h != NULL) {
			func(heap, h);
			h = h->hdr.h_next;
		}
	}
}

DUK_LOCAL void duk__assert_heaphdr_flags_cb(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(h));
	DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(h));
	DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(h));
	/* may have FINALIZED */
}
DUK_LOCAL void duk__assert_heaphdr_flags(duk_heap *heap) {
	duk__assert_walk_list(heap, heap->heap_allocated, duk__assert_heaphdr_flags_cb);
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);  /* Always handled to completion inline in DECREF. */
#endif
	/* XXX: Assertions for finalize_list? */
}

DUK_LOCAL void duk__assert_validity_cb1(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	DUK_ASSERT(DUK_HEAPHDR_IS_OBJECT(h) || DUK_HEAPHDR_IS_BUFFER(h));
	duk_heaphdr_assert_valid_subclassed(h);
}
DUK_LOCAL void duk__assert_validity_cb2(duk_heap *heap, duk_hstring *h) {
	DUK_UNREF(heap);
	DUK_ASSERT(DUK_HEAPHDR_IS_STRING((duk_heaphdr *) h));
	duk_heaphdr_assert_valid_subclassed((duk_heaphdr *) h);
}
DUK_LOCAL void duk__assert_validity(duk_heap *heap) {
	duk__assert_walk_list(heap, heap->heap_allocated, duk__assert_validity_cb1);
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__assert_walk_list(heap, heap->finalize_list, duk__assert_validity_cb1);
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__assert_walk_list(heap, heap->refzero_list, duk__assert_validity_cb1);
#endif
	duk__assert_walk_strtable(heap, duk__assert_validity_cb2);
}

#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_LOCAL void duk__assert_valid_refcounts_cb(duk_heap *heap, duk_heaphdr *h) {
	/* Cannot really assert much w.r.t. refcounts now. */

	DUK_UNREF(heap);
	if (DUK_HEAPHDR_GET_REFCOUNT(h) == 0 &&
	    DUK_HEAPHDR_HAS_FINALIZED(h)) {
		/* An object may be in heap_allocated list with a zero
		 * refcount if it has just been finalized and is waiting
		 * to be collected by the next cycle.
		 * (This doesn't currently happen however.)
		 */
	} else if (DUK_HEAPHDR_GET_REFCOUNT(h) == 0) {
		/* An object may be in heap_allocated list with a zero
		 * refcount also if it is a temporary object created
		 * during debugger paused state.  It will get collected
		 * by mark-and-sweep based on its reachability status
		 * (presumably not reachable because refcount is 0).
		 */
	}
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);  /* Unsigned. */
}
DUK_LOCAL void duk__assert_valid_refcounts(duk_heap *heap) {
	duk__assert_walk_list(heap, heap->heap_allocated, duk__assert_valid_refcounts_cb);
}

DUK_LOCAL void duk__clear_assert_refcounts_cb1(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	h->h_assert_refcount = 0;
}
DUK_LOCAL void duk__clear_assert_refcounts_cb2(duk_heap *heap, duk_hstring *h) {
	DUK_UNREF(heap);
	((duk_heaphdr *) h)->h_assert_refcount = 0;
}
DUK_LOCAL void duk__clear_assert_refcounts(duk_heap *heap) {
	duk__assert_walk_list(heap, heap->heap_allocated, duk__clear_assert_refcounts_cb1);
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__assert_walk_list(heap, heap->finalize_list, duk__clear_assert_refcounts_cb1);
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__assert_walk_list(heap, heap->refzero_list, duk__clear_assert_refcounts_cb1);
#endif
	duk__assert_walk_strtable(heap, duk__clear_assert_refcounts_cb2);
}

DUK_LOCAL void duk__check_refcount_heaphdr(duk_heaphdr *hdr) {
	duk_bool_t count_ok;
	duk_size_t expect_refc;

	/* The refcount check only makes sense for reachable objects on
	 * heap_allocated or string table, after the sweep phase.  Prior to
	 * sweep phase refcounts will include references that are not visible
	 * via reachability roots.
	 *
	 * Because we're called after the sweep phase, all heap objects on
	 * heap_allocated are reachable.  REACHABLE flags have already been
	 * cleared so we can't check them.
	 */

	/* ROM objects have intentionally incorrect refcount (1), but we won't
	 * check them.
	 */
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(hdr));

	expect_refc = hdr->h_assert_refcount;
	if (DUK_HEAPHDR_IS_STRING(hdr) && DUK_HSTRING_HAS_PINNED_LITERAL((duk_hstring *) hdr)) {
		expect_refc++;
	}
	count_ok = ((duk_size_t) DUK_HEAPHDR_GET_REFCOUNT(hdr) == expect_refc);
	if (!count_ok) {
		DUK_D(DUK_DPRINT("refcount mismatch for: %p: header=%ld counted=%ld --> %!iO",
		                 (void *) hdr, (long) DUK_HEAPHDR_GET_REFCOUNT(hdr),
		                 (long) hdr->h_assert_refcount, hdr));
		DUK_ASSERT(0);
	}
}

DUK_LOCAL void duk__check_assert_refcounts_cb1(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	duk__check_refcount_heaphdr(h);
}
DUK_LOCAL void duk__check_assert_refcounts_cb2(duk_heap *heap, duk_hstring *h) {
	DUK_UNREF(heap);
	duk__check_refcount_heaphdr((duk_heaphdr *) h);
}
DUK_LOCAL void duk__check_assert_refcounts(duk_heap *heap) {
	duk__assert_walk_list(heap, heap->heap_allocated, duk__check_assert_refcounts_cb1);
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__assert_walk_list(heap, heap->finalize_list, duk__check_assert_refcounts_cb1);
#endif
	/* XXX: Assert anything for refzero_list? */
	duk__assert_walk_strtable(heap, duk__check_assert_refcounts_cb2);
}
#endif  /* DUK_USE_REFERENCE_COUNTING */

#if defined(DUK_USE_LITCACHE_SIZE)
DUK_LOCAL void duk__assert_litcache_nulls(duk_heap *heap) {
	duk_uint_t i;
	duk_litcache_entry *e;

	e = heap->litcache;
	for (i = 0; i < DUK_USE_LITCACHE_SIZE; i++) {
		/* Entry addresses were NULLed before mark-and-sweep, check
		 * that they're still NULL afterwards to ensure no pointers
		 * were recorded through any side effects.
		 */
		DUK_ASSERT(e->addr == NULL);
	}
}
#endif  /* DUK_USE_LITCACHE_SIZE */
#endif  /* DUK_USE_ASSERTIONS */

/*
 *  Stats dump.
 */

#if defined(DUK_USE_DEBUG)
DUK_LOCAL void duk__dump_stats(duk_heap *heap) {
	DUK_D(DUK_DPRINT("stats executor: opcodes=%ld, interrupt=%ld, throw=%ld",
	                 (long) heap->stats_exec_opcodes, (long) heap->stats_exec_interrupt,
	                 (long) heap->stats_exec_throw));
	DUK_D(DUK_DPRINT("stats call: all=%ld, tailcall=%ld, ecmatoecma=%ld",
	                 (long) heap->stats_call_all, (long) heap->stats_call_tailcall,
	                 (long) heap->stats_call_ecmatoecma));
	DUK_D(DUK_DPRINT("stats safecall: all=%ld, nothrow=%ld, throw=%ld",
	                 (long) heap->stats_safecall_all, (long) heap->stats_safecall_nothrow,
	                 (long) heap->stats_safecall_throw));
	DUK_D(DUK_DPRINT("stats mark-and-sweep: try_count=%ld, skip_count=%ld, emergency_count=%ld",
	                 (long) heap->stats_ms_try_count, (long) heap->stats_ms_skip_count,
	                 (long) heap->stats_ms_emergency_count));
	DUK_D(DUK_DPRINT("stats stringtable: intern_hit=%ld, intern_miss=%ld, "
	                 "resize_check=%ld, resize_grow=%ld, resize_shrink=%ld, "
	                 "litcache_hit=%ld, litcache_miss=%ld, litcache_pin=%ld",
	                 (long) heap->stats_strtab_intern_hit, (long) heap->stats_strtab_intern_miss,
	                 (long) heap->stats_strtab_resize_check, (long) heap->stats_strtab_resize_grow,
	                 (long) heap->stats_strtab_resize_shrink, (long) heap->stats_strtab_litcache_hit,
	                 (long) heap->stats_strtab_litcache_miss, (long) heap->stats_strtab_litcache_pin));
	DUK_D(DUK_DPRINT("stats object: realloc_props=%ld, abandon_array=%ld",
	                 (long) heap->stats_object_realloc_props, (long) heap->stats_object_abandon_array));
	DUK_D(DUK_DPRINT("stats getownpropdesc: count=%ld, hit=%ld, miss=%ld",
	                 (long) heap->stats_getownpropdesc_count, (long) heap->stats_getownpropdesc_hit,
	                 (long) heap->stats_getownpropdesc_miss));
	DUK_D(DUK_DPRINT("stats getpropdesc: count=%ld, hit=%ld, miss=%ld",
	                 (long) heap->stats_getpropdesc_count, (long) heap->stats_getpropdesc_hit,
	                 (long) heap->stats_getpropdesc_miss));
	DUK_D(DUK_DPRINT("stats getprop: all=%ld, arrayidx=%ld, bufobjidx=%ld, "
	                 "bufferidx=%ld, bufferlen=%ld, stringidx=%ld, stringlen=%ld, "
	                 "proxy=%ld, arguments=%ld",
	                 (long) heap->stats_getprop_all, (long) heap->stats_getprop_arrayidx,
	                 (long) heap->stats_getprop_bufobjidx, (long) heap->stats_getprop_bufferidx,
	                 (long) heap->stats_getprop_bufferlen, (long) heap->stats_getprop_stringidx,
	                 (long) heap->stats_getprop_stringlen, (long) heap->stats_getprop_proxy,
	                 (long) heap->stats_getprop_arguments));
	DUK_D(DUK_DPRINT("stats putprop: all=%ld, arrayidx=%ld, bufobjidx=%ld, "
	                 "bufferidx=%ld, proxy=%ld",
	                 (long) heap->stats_putprop_all, (long) heap->stats_putprop_arrayidx,
	                 (long) heap->stats_putprop_bufobjidx, (long) heap->stats_putprop_bufferidx,
	                 (long) heap->stats_putprop_proxy));
	DUK_D(DUK_DPRINT("stats getvar: all=%ld",
	                 (long) heap->stats_getvar_all));
	DUK_D(DUK_DPRINT("stats putvar: all=%ld",
	                 (long) heap->stats_putvar_all));
	DUK_D(DUK_DPRINT("stats envrec: delayedcreate=%ld, create=%ld, newenv=%ld, oldenv=%ld, pushclosure=%ld",
	                 (long) heap->stats_envrec_delayedcreate,
	                 (long) heap->stats_envrec_create,
	                 (long) heap->stats_envrec_newenv,
	                 (long) heap->stats_envrec_oldenv,
	                 (long) heap->stats_envrec_pushclosure));
}
#endif  /* DUK_USE_DEBUG */

/*
 *  Main mark-and-sweep function.
 *
 *  'flags' represents the features requested by the caller.  The current
 *  heap->ms_base_flags is ORed automatically into the flags; the base flags
 *  mask typically prevents certain mark-and-sweep operation to avoid trouble.
 */

DUK_INTERNAL void duk_heap_mark_and_sweep(duk_heap *heap, duk_small_uint_t flags) {
	duk_size_t count_keep_obj;
	duk_size_t count_keep_str;
#if defined(DUK_USE_VOLUNTARY_GC)
	duk_size_t tmp;
#endif

	DUK_STATS_INC(heap, stats_ms_try_count);
#if defined(DUK_USE_DEBUG)
	if (flags & DUK_MS_FLAG_EMERGENCY) {
		DUK_STATS_INC(heap, stats_ms_emergency_count);
	}
#endif

	/* If debugger is paused, garbage collection is disabled by default.
	 * This is achieved by bumping ms_prevent_count when becoming paused.
	 */
	DUK_ASSERT(!DUK_HEAP_HAS_DEBUGGER_PAUSED(heap) || heap->ms_prevent_count > 0);

	/* Prevention/recursion check as soon as possible because we may
	 * be called a number of times when voluntary mark-and-sweep is
	 * pending.
	 */
	if (heap->ms_prevent_count != 0) {
		DUK_DD(DUK_DDPRINT("reject recursive mark-and-sweep"));
		DUK_STATS_INC(heap, stats_ms_skip_count);
		return;
	}
	DUK_ASSERT(heap->ms_running == 0);  /* ms_prevent_count is bumped when ms_running is set */

	/* Heap_thread is used during mark-and-sweep for refcount finalization
	 * (it's also used for finalizer execution once mark-and-sweep is
	 * complete).  Heap allocation code ensures heap_thread is set and
	 * properly initialized before setting ms_prevent_count to 0.
	 */
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(heap->heap_thread->valstack != NULL);

	DUK_D(DUK_DPRINT("garbage collect (mark-and-sweep) starting, requested flags: 0x%08lx, effective flags: 0x%08lx",
	                 (unsigned long) flags, (unsigned long) (flags | heap->ms_base_flags)));

	flags |= heap->ms_base_flags;
#if defined(DUK_USE_FINALIZER_SUPPORT)
	if (heap->finalize_list != NULL) {
		flags |= DUK_MS_FLAG_POSTPONE_RESCUE;
	}
#endif

	/*
	 *  Assertions before
	 */

#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(heap->ms_prevent_count == 0);
	DUK_ASSERT(heap->ms_running == 0);
	DUK_ASSERT(!DUK_HEAP_HAS_DEBUGGER_PAUSED(heap));
	DUK_ASSERT(!DUK_HEAP_HAS_MARKANDSWEEP_RECLIMIT_REACHED(heap));
	DUK_ASSERT(heap->ms_recursion_depth == 0);
	duk__assert_heaphdr_flags(heap);
	duk__assert_validity(heap);
#if defined(DUK_USE_REFERENCE_COUNTING)
	/* Note: heap->refzero_free_running may be true; a refcount
	 * finalizer may trigger a mark-and-sweep.
	 */
	duk__assert_valid_refcounts(heap);
#endif  /* DUK_USE_REFERENCE_COUNTING */
#endif  /* DUK_USE_ASSERTIONS */

	/*
	 *  Begin
	 */

	DUK_ASSERT(heap->ms_prevent_count == 0);
	DUK_ASSERT(heap->ms_running == 0);
	heap->ms_prevent_count = 1;
	heap->ms_running = 1;

	/*
	 *  Free activation/catcher freelists on every mark-and-sweep for now.
	 *  This is an initial rough draft; ideally we'd keep count of the
	 *  freelist size and free only excess entries.
	 */

	DUK_D(DUK_DPRINT("freeing temporary freelists"));
	duk_heap_free_freelists(heap);

	/*
	 *  Mark roots, hoping that recursion limit is not normally hit.
	 *  If recursion limit is hit, run additional reachability rounds
	 *  starting from "temproots" until marking is complete.
	 *
	 *  Marking happens in two phases: first we mark actual reachability
	 *  roots (and run "temproots" to complete the process).  Then we
	 *  check which objects are unreachable and are finalizable; such
	 *  objects are marked as FINALIZABLE and marked as reachability
	 *  (and "temproots" is run again to complete the process).
	 *
	 *  The heap finalize_list must also be marked as a reachability root.
	 *  There may be objects on the list from a previous round if the
	 *  previous run had finalizer skip flag.
	 */

#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_REFERENCE_COUNTING)
	duk__clear_assert_refcounts(heap);
#endif
#if defined(DUK_USE_LITCACHE_SIZE)
	duk__wipe_litcache(heap);
#endif
	duk__mark_roots_heap(heap);               /* Mark main reachability roots. */
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);   /* Always handled to completion inline in DECREF. */
#endif
	duk__mark_temproots_by_heap_scan(heap);   /* Temproots. */

#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__mark_finalizable(heap);              /* Mark finalizable as reachability roots. */
	duk__mark_finalize_list(heap);            /* Mark finalizer work list as reachability roots. */
#endif
	duk__mark_temproots_by_heap_scan(heap);   /* Temproots. */

	/*
	 *  Sweep garbage and remove marking flags, and move objects with
	 *  finalizers to the finalizer work list.
	 *
	 *  Objects to be swept need to get their refcounts finalized before
	 *  they are swept.  In other words, their target object refcounts
	 *  need to be decreased.  This has to be done before freeing any
	 *  objects to avoid decref'ing dangling pointers (which may happen
	 *  even without bugs, e.g. with reference loops)
	 *
	 *  Because strings don't point to other heap objects, similar
	 *  finalization is not necessary for strings.
	 */

	/* XXX: more emergency behavior, e.g. find smaller hash sizes etc */

#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__finalize_refcounts(heap);
#endif
	duk__sweep_heap(heap, flags, &count_keep_obj);
	duk__sweep_stringtable(heap, &count_keep_str);
#if defined(DUK_USE_ASSERTIONS) && defined(DUK_USE_REFERENCE_COUNTING)
	duk__check_assert_refcounts(heap);
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
	DUK_ASSERT(heap->refzero_list == NULL);   /* Always handled to completion inline in DECREF. */
#endif
#if defined(DUK_USE_FINALIZER_SUPPORT)
	duk__clear_finalize_list_flags(heap);
#endif

	/*
	 *  Object compaction (emergency only).
	 *
	 *  Object compaction is a separate step after sweeping, as there is
	 *  more free memory for it to work with.  Also, currently compaction
	 *  may insert new objects into the heap allocated list and the string
	 *  table which we don't want to do during a sweep (the reachability
	 *  flags of such objects would be incorrect).  The objects inserted
	 *  are currently:
	 *
	 *    - a temporary duk_hbuffer for a new properties allocation
	 *    - if array part is abandoned, string keys are interned
	 *
	 *  The object insertions go to the front of the list, so they do not
	 *  cause an infinite loop (they are not compacted).
	 *
	 *  At present compaction is not allowed when mark-and-sweep runs
	 *  during error handling because it involves a duk_safe_call()
	 *  interfering with error state.
	 */

	if ((flags & DUK_MS_FLAG_EMERGENCY) &&
	    !(flags & DUK_MS_FLAG_NO_OBJECT_COMPACTION)) {
		if (heap->lj.type != DUK_LJ_TYPE_UNKNOWN) {
			DUK_D(DUK_DPRINT("lj.type (%ld) not DUK_LJ_TYPE_UNKNOWN, skip object compaction", (long) heap->lj.type));
		} else {
			DUK_D(DUK_DPRINT("object compaction"));
			duk__compact_objects(heap);
		}
	}

	/*
	 *  String table resize check.
	 *
	 *  This is mainly useful in emergency GC: if the string table load
	 *  factor is really low for some reason, we can shrink the string
	 *  table to a smaller size and free some memory in the process.
	 *  Only execute in emergency GC.  String table has internal flags
	 *  to protect against recursive resizing if this mark-and-sweep pass
	 *  was triggered by a string table resize.
	 */

	if (flags & DUK_MS_FLAG_EMERGENCY) {
		DUK_D(DUK_DPRINT("stringtable resize check in emergency gc"));
		duk_heap_strtable_force_resize(heap);
	}

	/*
	 *  Finish
	 */

	DUK_ASSERT(heap->ms_prevent_count == 1);
	DUK_ASSERT(heap->ms_running == 1);
	heap->ms_prevent_count = 0;
	heap->ms_running = 0;

	/*
	 *  Assertions after
	 */

#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(heap->ms_prevent_count == 0);
	DUK_ASSERT(!DUK_HEAP_HAS_MARKANDSWEEP_RECLIMIT_REACHED(heap));
	DUK_ASSERT(heap->ms_recursion_depth == 0);
	duk__assert_heaphdr_flags(heap);
	duk__assert_validity(heap);
#if defined(DUK_USE_REFERENCE_COUNTING)
	/* Note: heap->refzero_free_running may be true; a refcount
	 * finalizer may trigger a mark-and-sweep.
	 */
	duk__assert_valid_refcounts(heap);
#endif  /* DUK_USE_REFERENCE_COUNTING */
#if defined(DUK_USE_LITCACHE_SIZE)
	duk__assert_litcache_nulls(heap);
#endif  /* DUK_USE_LITCACHE_SIZE */
#endif  /* DUK_USE_ASSERTIONS */

	/*
	 *  Reset trigger counter
	 */

#if defined(DUK_USE_VOLUNTARY_GC)
	tmp = (count_keep_obj + count_keep_str) / 256;
	heap->ms_trigger_counter = (duk_int_t) (
	    (tmp * DUK_HEAP_MARK_AND_SWEEP_TRIGGER_MULT) +
	    DUK_HEAP_MARK_AND_SWEEP_TRIGGER_ADD);
	DUK_D(DUK_DPRINT("garbage collect (mark-and-sweep) finished: %ld objects kept, %ld strings kept, trigger reset to %ld",
	                 (long) count_keep_obj, (long) count_keep_str, (long) heap->ms_trigger_counter));
#else
	DUK_D(DUK_DPRINT("garbage collect (mark-and-sweep) finished: %ld objects kept, %ld strings kept, no voluntary trigger",
	                 (long) count_keep_obj, (long) count_keep_str));
#endif

	/*
	 *  Stats dump
	 */

#if defined(DUK_USE_DEBUG)
	duk__dump_stats(heap);
#endif

	/*
	 *  Finalize objects in the finalization work list.  Finalized
	 *  objects are queued back to heap_allocated with FINALIZED set.
	 *
	 *  Since finalizers may cause arbitrary side effects, they are
	 *  prevented e.g. during string table and object property allocation
	 *  resizing using heap->pf_prevent_count.  In this case the objects
	 *  remain in the finalization work list after mark-and-sweep exits
	 *  and they may be finalized on the next pass or any DECREF checking
	 *  for finalize_list.
	 *
	 *  As of Duktape 2.1 finalization happens outside mark-and-sweep
	 *  protection.  Mark-and-sweep is allowed while the finalize_list
	 *  is being processed, but no rescue decisions are done while the
	 *  process is on-going.  This avoids incorrect rescue decisions
	 *  if an object is considered reachable (and thus rescued) because
	 *  of a reference via finalize_list (which is considered a reachability
	 *  root).  When finalize_list is being processed, reachable objects
	 *  with FINALIZED set will just keep their FINALIZED flag for later
	 *  mark-and-sweep processing.
	 *
	 *  This could also be handled (a bit better) by having a more refined
	 *  notion of reachability for rescue/free decisions.
	 *
	 *  XXX: avoid finalizer execution when doing emergency GC?
	 */

#if defined(DUK_USE_FINALIZER_SUPPORT)
	/* Attempt to process finalize_list, pf_prevent_count check
	 * is inside the target.
	 */
	duk_heap_process_finalize_list(heap);
#endif  /* DUK_USE_FINALIZER_SUPPORT */
}
/*
 *  Memory allocation handling.
 */

/* #include duk_internal.h -> already included */

/*
 *  Allocate memory with garbage collection.
 */

/* Slow path: voluntary GC triggered, first alloc attempt failed, or zero size. */
DUK_LOCAL DUK_NOINLINE_PERF DUK_COLD void *duk__heap_mem_alloc_slowpath(duk_heap *heap, duk_size_t size) {
	void *res;
	duk_small_int_t i;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->alloc_func != NULL);
	DUK_ASSERT_DISABLE(size >= 0);

	if (size == 0) {
		DUK_D(DUK_DPRINT("zero size alloc in slow path, return NULL"));
		return NULL;
	}

	DUK_D(DUK_DPRINT("first alloc attempt failed or voluntary GC limit reached, attempt to gc and retry"));

#if 0
	/*
	 *  If GC is already running there is no point in attempting a GC
	 *  because it will be skipped.  This could be checked for explicitly,
	 *  but it isn't actually needed: the loop below will eventually
	 *  fail resulting in a NULL.
	 */

	if (heap->ms_prevent_count != 0) {
		DUK_D(DUK_DPRINT("duk_heap_mem_alloc() failed, gc in progress (gc skipped), alloc size %ld", (long) size));
		return NULL;
	}
#endif

	/*
	 *  Retry with several GC attempts.  Initial attempts are made without
	 *  emergency mode; later attempts use emergency mode which minimizes
	 *  memory allocations forcibly.
	 */

	for (i = 0; i < DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_LIMIT; i++) {
		duk_small_uint_t flags;

		flags = 0;
		if (i >= DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_EMERGENCY_LIMIT - 1) {
			flags |= DUK_MS_FLAG_EMERGENCY;
		}

		duk_heap_mark_and_sweep(heap, flags);

		DUK_ASSERT(size > 0);
		res = heap->alloc_func(heap->heap_udata, size);
		if (res != NULL) {
			DUK_D(DUK_DPRINT("duk_heap_mem_alloc() succeeded after gc (pass %ld), alloc size %ld",
			                 (long) (i + 1), (long) size));
			return res;
		}
	}

	DUK_D(DUK_DPRINT("duk_heap_mem_alloc() failed even after gc, alloc size %ld", (long) size));
	return NULL;
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_alloc(duk_heap *heap, duk_size_t size) {
	void *res;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->alloc_func != NULL);
	DUK_ASSERT_DISABLE(size >= 0);

#if defined(DUK_USE_VOLUNTARY_GC)
	/* Voluntary periodic GC (if enabled). */
	if (DUK_UNLIKELY(--(heap)->ms_trigger_counter < 0)) {
		goto slowpath;
	}
#endif

#if defined(DUK_USE_GC_TORTURE)
	/* Simulate alloc failure on every alloc, except when mark-and-sweep
	 * is running.
	 */
	if (heap->ms_prevent_count == 0) {
		DUK_DDD(DUK_DDDPRINT("gc torture enabled, pretend that first alloc attempt fails"));
		res = NULL;
		DUK_UNREF(res);
		goto slowpath;
	}
#endif

	/* Zero-size allocation should happen very rarely (if at all), so
	 * don't check zero size on NULL; handle it in the slow path
	 * instead.  This reduces size of inlined code.
	 */
	res = heap->alloc_func(heap->heap_udata, size);
	if (DUK_LIKELY(res != NULL)) {
		return res;
	}

 slowpath:

	if (size == 0) {
		DUK_D(DUK_DPRINT("first alloc attempt returned NULL for zero size alloc, use slow path to deal with it"));
	} else {
		DUK_D(DUK_DPRINT("first alloc attempt failed, attempt to gc and retry"));
	}
	return duk__heap_mem_alloc_slowpath(heap, size);
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_alloc_zeroed(duk_heap *heap, duk_size_t size) {
	void *res;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->alloc_func != NULL);
	DUK_ASSERT_DISABLE(size >= 0);

	res = DUK_ALLOC(heap, size);
	if (DUK_LIKELY(res != NULL)) {
		duk_memzero(res, size);
	}
	return res;
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_alloc_checked(duk_hthread *thr, duk_size_t size) {
	void *res;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->heap->alloc_func != NULL);

	res = duk_heap_mem_alloc(thr->heap, size);
	if (DUK_LIKELY(res != NULL)) {
		return res;
	} else if (size == 0) {
		DUK_ASSERT(res == NULL);
		return res;
	}
	DUK_ERROR_ALLOC_FAILED(thr);
	DUK_WO_NORETURN(return NULL;);
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_alloc_checked_zeroed(duk_hthread *thr, duk_size_t size) {
	void *res;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->heap->alloc_func != NULL);

	res = duk_heap_mem_alloc(thr->heap, size);
	if (DUK_LIKELY(res != NULL)) {
		duk_memzero(res, size);
		return res;
	} else if (size == 0) {
		DUK_ASSERT(res == NULL);
		return res;
	}
	DUK_ERROR_ALLOC_FAILED(thr);
	DUK_WO_NORETURN(return NULL;);
}

/*
 *  Reallocate memory with garbage collection.
 */

/* Slow path: voluntary GC triggered, first realloc attempt failed, or zero size. */
DUK_LOCAL DUK_NOINLINE_PERF DUK_COLD void *duk__heap_mem_realloc_slowpath(duk_heap *heap, void *ptr, duk_size_t newsize) {
	void *res;
	duk_small_int_t i;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->realloc_func != NULL);
	/* ptr may be NULL */
	DUK_ASSERT_DISABLE(newsize >= 0);

	/* Newsize was 0 and realloc() returned NULL, this has the semantics
	 * of free(oldptr), i.e. memory was successfully freed.
	 */
	if (newsize == 0) {
		DUK_D(DUK_DPRINT("zero size realloc in slow path, return NULL"));
		return NULL;
	}

	DUK_D(DUK_DPRINT("first realloc attempt failed, attempt to gc and retry"));

#if 0
	/*
	 *  Avoid a GC if GC is already running.  See duk_heap_mem_alloc().
	 */

	if (heap->ms_prevent_count != 0) {
		DUK_D(DUK_DPRINT("duk_heap_mem_realloc() failed, gc in progress (gc skipped), alloc size %ld", (long) newsize));
		return NULL;
	}
#endif

	/*
	 *  Retry with several GC attempts.  Initial attempts are made without
	 *  emergency mode; later attempts use emergency mode which minimizes
	 *  memory allocations forcibly.
	 */

	for (i = 0; i < DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_LIMIT; i++) {
		duk_small_uint_t flags;

		flags = 0;
		if (i >= DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_EMERGENCY_LIMIT - 1) {
			flags |= DUK_MS_FLAG_EMERGENCY;
		}

		duk_heap_mark_and_sweep(heap, flags);

		DUK_ASSERT(newsize > 0);
		res = heap->realloc_func(heap->heap_udata, ptr, newsize);
		if (res || newsize == 0) {
			DUK_D(DUK_DPRINT("duk_heap_mem_realloc() succeeded after gc (pass %ld), alloc size %ld",
			                 (long) (i + 1), (long) newsize));
			return res;
		}
	}

	DUK_D(DUK_DPRINT("duk_heap_mem_realloc() failed even after gc, alloc size %ld", (long) newsize));
	return NULL;
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_realloc(duk_heap *heap, void *ptr, duk_size_t newsize) {
	void *res;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->realloc_func != NULL);
	/* ptr may be NULL */
	DUK_ASSERT_DISABLE(newsize >= 0);

#if defined(DUK_USE_VOLUNTARY_GC)
	/* Voluntary periodic GC (if enabled). */
	if (DUK_UNLIKELY(--(heap)->ms_trigger_counter < 0)) {
		goto slowpath;
	}
#endif

#if defined(DUK_USE_GC_TORTURE)
	/* Simulate alloc failure on every realloc, except when mark-and-sweep
	 * is running.
	 */
	if (heap->ms_prevent_count == 0) {
		DUK_DDD(DUK_DDDPRINT("gc torture enabled, pretend that first realloc attempt fails"));
		res = NULL;
		DUK_UNREF(res);
		goto slowpath;
	}
#endif

	res = heap->realloc_func(heap->heap_udata, ptr, newsize);
	if (DUK_LIKELY(res != NULL)) {
		return res;
	}

 slowpath:

	if (newsize == 0) {
		DUK_D(DUK_DPRINT("first realloc attempt returned NULL for zero size realloc, use slow path to deal with it"));
	} else {
		DUK_D(DUK_DPRINT("first realloc attempt failed, attempt to gc and retry"));
	}
	return duk__heap_mem_realloc_slowpath(heap, ptr, newsize);
}

/*
 *  Reallocate memory with garbage collection, using a callback to provide
 *  the current allocated pointer.  This variant is used when a mark-and-sweep
 *  (e.g. finalizers) might change the original pointer.
 */

/* Slow path: voluntary GC triggered, first realloc attempt failed, or zero size. */
DUK_LOCAL DUK_NOINLINE_PERF DUK_COLD void *duk__heap_mem_realloc_indirect_slowpath(duk_heap *heap, duk_mem_getptr cb, void *ud, duk_size_t newsize) {
	void *res;
	duk_small_int_t i;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->realloc_func != NULL);
	DUK_ASSERT_DISABLE(newsize >= 0);

	if (newsize == 0) {
		DUK_D(DUK_DPRINT("zero size indirect realloc in slow path, return NULL"));
		return NULL;
	}

	DUK_D(DUK_DPRINT("first indirect realloc attempt failed, attempt to gc and retry"));

#if 0
	/*
	 *  Avoid a GC if GC is already running.  See duk_heap_mem_alloc().
	 */

	if (heap->ms_prevent_count != 0) {
		DUK_D(DUK_DPRINT("duk_heap_mem_realloc_indirect() failed, gc in progress (gc skipped), alloc size %ld", (long) newsize));
		return NULL;
	}
#endif

	/*
	 *  Retry with several GC attempts.  Initial attempts are made without
	 *  emergency mode; later attempts use emergency mode which minimizes
	 *  memory allocations forcibly.
	 */

	for (i = 0; i < DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_LIMIT; i++) {
		duk_small_uint_t flags;

#if defined(DUK_USE_DEBUG)
		void *ptr_pre;
		void *ptr_post;
#endif

#if defined(DUK_USE_DEBUG)
		ptr_pre = cb(heap, ud);
#endif
		flags = 0;
		if (i >= DUK_HEAP_ALLOC_FAIL_MARKANDSWEEP_EMERGENCY_LIMIT - 1) {
			flags |= DUK_MS_FLAG_EMERGENCY;
		}

		duk_heap_mark_and_sweep(heap, flags);
#if defined(DUK_USE_DEBUG)
		ptr_post = cb(heap, ud);
		if (ptr_pre != ptr_post) {
			DUK_DD(DUK_DDPRINT("realloc base pointer changed by mark-and-sweep: %p -> %p",
			                   (void *) ptr_pre, (void *) ptr_post));
		}
#endif

		/* Note: key issue here is to re-lookup the base pointer on every attempt.
		 * The pointer being reallocated may change after every mark-and-sweep.
		 */

		DUK_ASSERT(newsize > 0);
		res = heap->realloc_func(heap->heap_udata, cb(heap, ud), newsize);
		if (res || newsize == 0) {
			DUK_D(DUK_DPRINT("duk_heap_mem_realloc_indirect() succeeded after gc (pass %ld), alloc size %ld",
			                 (long) (i + 1), (long) newsize));
			return res;
		}
	}

	DUK_D(DUK_DPRINT("duk_heap_mem_realloc_indirect() failed even after gc, alloc size %ld", (long) newsize));
	return NULL;
}

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void *duk_heap_mem_realloc_indirect(duk_heap *heap, duk_mem_getptr cb, void *ud, duk_size_t newsize) {
	void *res;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->realloc_func != NULL);
	DUK_ASSERT_DISABLE(newsize >= 0);

#if defined(DUK_USE_VOLUNTARY_GC)
	/* Voluntary periodic GC (if enabled). */
	if (DUK_UNLIKELY(--(heap)->ms_trigger_counter < 0)) {
		goto slowpath;
	}
#endif

#if defined(DUK_USE_GC_TORTURE)
	/* Simulate alloc failure on every realloc, except when mark-and-sweep
	 * is running.
	 */
	if (heap->ms_prevent_count == 0) {
		DUK_DDD(DUK_DDDPRINT("gc torture enabled, pretend that first indirect realloc attempt fails"));
		res = NULL;
		DUK_UNREF(res);
		goto slowpath;
	}
#endif

	res = heap->realloc_func(heap->heap_udata, cb(heap, ud), newsize);
	if (DUK_LIKELY(res != NULL)) {
		return res;
	}

 slowpath:

	if (newsize == 0) {
		DUK_D(DUK_DPRINT("first indirect realloc attempt returned NULL for zero size realloc, use slow path to deal with it"));
	} else {
		DUK_D(DUK_DPRINT("first indirect realloc attempt failed, attempt to gc and retry"));
	}
	return duk__heap_mem_realloc_indirect_slowpath(heap, cb, ud, newsize);
}

/*
 *  Free memory
 */

DUK_INTERNAL DUK_INLINE_PERF DUK_HOT void duk_heap_mem_free(duk_heap *heap, void *ptr) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->free_func != NULL);
	/* ptr may be NULL */

	/* Must behave like a no-op with NULL and any pointer returned from
	 * malloc/realloc with zero size.
	 */
	heap->free_func(heap->heap_udata, ptr);

	/* Never perform a GC (even voluntary) in a memory free, otherwise
	 * all call sites doing frees would need to deal with the side effects.
	 * No need to update voluntary GC counter either.
	 */
}
/*
 *  Support functions for duk_heap.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL void duk_heap_insert_into_heap_allocated(duk_heap *heap, duk_heaphdr *hdr) {
	duk_heaphdr *root;

	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(hdr) != DUK_HTYPE_STRING);

	root = heap->heap_allocated;
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
	if (root != NULL) {
		DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, root) == NULL);
		DUK_HEAPHDR_SET_PREV(heap, root, hdr);
	}
	DUK_HEAPHDR_SET_PREV(heap, hdr, NULL);
#endif
	DUK_HEAPHDR_SET_NEXT(heap, hdr, root);
	DUK_HEAPHDR_ASSERT_LINKS(heap, hdr);
	DUK_HEAPHDR_ASSERT_LINKS(heap, root);
	heap->heap_allocated = hdr;
}

#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_INTERNAL void duk_heap_remove_from_heap_allocated(duk_heap *heap, duk_heaphdr *hdr) {
	duk_heaphdr *prev;
	duk_heaphdr *next;

	/* Strings are in string table. */
	DUK_ASSERT(hdr != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(hdr) != DUK_HTYPE_STRING);

	/* Target 'hdr' must be in heap_allocated (not e.g. finalize_list).
	 * If not, heap lists will become corrupted so assert early for it.
	 */
#if defined(DUK_USE_ASSERTIONS)
	{
		duk_heaphdr *tmp;
		for (tmp = heap->heap_allocated; tmp != NULL; tmp = DUK_HEAPHDR_GET_NEXT(heap, tmp)) {
			if (tmp == hdr) {
				break;
			}
		}
		DUK_ASSERT(tmp == hdr);
	}
#endif

	/* Read/write only once to minimize pointer compression calls. */
	prev = DUK_HEAPHDR_GET_PREV(heap, hdr);
	next = DUK_HEAPHDR_GET_NEXT(heap, hdr);

	if (prev != NULL) {
		DUK_ASSERT(heap->heap_allocated != hdr);
		DUK_HEAPHDR_SET_NEXT(heap, prev, next);
	} else {
		DUK_ASSERT(heap->heap_allocated == hdr);
		heap->heap_allocated = next;
	}
	if (next != NULL) {
		DUK_HEAPHDR_SET_PREV(heap, next, prev);
	} else {
		;
	}
}
#endif  /* DUK_USE_REFERENCE_COUNTING */

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL void duk_heap_insert_into_finalize_list(duk_heap *heap, duk_heaphdr *hdr) {
	duk_heaphdr *root;

	root = heap->finalize_list;
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
	DUK_HEAPHDR_SET_PREV(heap, hdr, NULL);
	if (root != NULL) {
		DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, root) == NULL);
		DUK_HEAPHDR_SET_PREV(heap, root, hdr);
	}
#endif
	DUK_HEAPHDR_SET_NEXT(heap, hdr, root);
	DUK_HEAPHDR_ASSERT_LINKS(heap, hdr);
	DUK_HEAPHDR_ASSERT_LINKS(heap, root);
	heap->finalize_list = hdr;
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL void duk_heap_remove_from_finalize_list(duk_heap *heap, duk_heaphdr *hdr) {
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
	duk_heaphdr *next;
	duk_heaphdr *prev;

	next = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	prev = DUK_HEAPHDR_GET_PREV(heap, hdr);
	if (next != NULL) {
		DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, next) == hdr);
		DUK_HEAPHDR_SET_PREV(heap, next, prev);
	}
	if (prev == NULL) {
		DUK_ASSERT(hdr == heap->finalize_list);
		heap->finalize_list = next;
	} else {
		DUK_ASSERT(hdr != heap->finalize_list);
		DUK_HEAPHDR_SET_NEXT(heap, prev, next);
	}
#else
	duk_heaphdr *next;
	duk_heaphdr *curr;

	/* Random removal is expensive: we need to locate the previous element
	 * because we don't have a 'prev' pointer.
	 */
	curr = heap->finalize_list;
	if (curr == hdr) {
		heap->finalize_list = DUK_HEAPHDR_GET_NEXT(heap, curr);
	} else {
		DUK_ASSERT(hdr != heap->finalize_list);
		for (;;) {
			DUK_ASSERT(curr != NULL);  /* Caller responsibility. */

			next = DUK_HEAPHDR_GET_NEXT(heap, curr);
			if (next == hdr) {
				next = DUK_HEAPHDR_GET_NEXT(heap, hdr);
				DUK_HEAPHDR_SET_NEXT(heap, curr, next);
				break;
			}
		}
	}
#endif
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL duk_bool_t duk_heap_in_heap_allocated(duk_heap *heap, duk_heaphdr *ptr) {
	duk_heaphdr *curr;
	DUK_ASSERT(heap != NULL);

	for (curr = heap->heap_allocated; curr != NULL; curr = DUK_HEAPHDR_GET_NEXT(heap, curr)) {
		if (curr == ptr) {
			return 1;
		}
	}
	return 0;
}
#endif  /* DUK_USE_ASSERTIONS */

#if defined(DUK_USE_INTERRUPT_COUNTER)
DUK_INTERNAL void duk_heap_switch_thread(duk_heap *heap, duk_hthread *new_thr) {
	duk_hthread *curr_thr;

	DUK_ASSERT(heap != NULL);

	if (new_thr != NULL) {
		curr_thr = heap->curr_thread;
		if (curr_thr == NULL) {
			/* For initial entry use default value; zero forces an
			 * interrupt before executing the first insturction.
			 */
			DUK_DD(DUK_DDPRINT("switch thread, initial entry, init default interrupt counter"));
			new_thr->interrupt_counter = 0;
			new_thr->interrupt_init = 0;
		} else {
			/* Copy interrupt counter/init value state to new thread (if any).
			 * It's OK for new_thr to be the same as curr_thr.
			 */
#if defined(DUK_USE_DEBUG)
			if (new_thr != curr_thr) {
				DUK_DD(DUK_DDPRINT("switch thread, not initial entry, copy interrupt counter"));
			}
#endif
			new_thr->interrupt_counter = curr_thr->interrupt_counter;
			new_thr->interrupt_init = curr_thr->interrupt_init;
		}
	} else {
		DUK_DD(DUK_DDPRINT("switch thread, new thread is NULL, no interrupt counter changes"));
	}

	heap->curr_thread = new_thr;  /* may be NULL */
}
#endif  /* DUK_USE_INTERRUPT_COUNTER */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL void duk_heap_assert_valid(duk_heap *heap) {
	DUK_ASSERT(heap != NULL);
}
#endif
/*
 *  Reference counting implementation.
 *
 *  INCREF/DECREF, finalization and freeing of objects whose refcount reaches
 *  zero (refzero).  These operations are very performance sensitive, so
 *  various small tricks are used in an attempt to maximize speed.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_REFERENCE_COUNTING)

#if !defined(DUK_USE_DOUBLE_LINKED_HEAP)
#error internal error, reference counting requires a double linked heap
#endif

/*
 *  Heap object refcount finalization.
 *
 *  When an object is about to be freed, all other objects it refers to must
 *  be decref'd.  Refcount finalization does NOT free the object or its inner
 *  allocations (mark-and-sweep shares these helpers), it just manipulates
 *  the refcounts.
 *
 *  Note that any of the DECREFs may cause a refcount to drop to zero.  If so,
 *  the object won't be refzero processed inline, but will just be queued to
 *  refzero_list and processed by an earlier caller working on refzero_list,
 *  eliminating C recursion from even long refzero cascades.  If refzero
 *  finalization is triggered by mark-and-sweep, refzero conditions are ignored
 *  (objects are not even queued to refzero_list) because mark-and-sweep deals
 *  with them; refcounts are still updated so that they remain in sync with
 *  actual references.
 */

DUK_LOCAL void duk__decref_tvals_norz(duk_hthread *thr, duk_tval *tv, duk_idx_t count) {
	DUK_ASSERT(count == 0 || tv != NULL);

	while (count-- > 0) {
		DUK_TVAL_DECREF_NORZ(thr, tv);
		tv++;
	}
}

DUK_INTERNAL void duk_hobject_refcount_finalize_norz(duk_heap *heap, duk_hobject *h) {
	duk_hthread *thr;
	duk_uint_fast32_t i;
	duk_uint_fast32_t n;
	duk_propvalue *p_val;
	duk_tval *p_tv;
	duk_hstring **p_key;
	duk_uint8_t *p_flag;
	duk_hobject *h_proto;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(h);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h) == DUK_HTYPE_OBJECT);

	thr = heap->heap_thread;
	DUK_ASSERT(thr != NULL);

	p_key = DUK_HOBJECT_E_GET_KEY_BASE(heap, h);
	p_val = DUK_HOBJECT_E_GET_VALUE_BASE(heap, h);
	p_flag = DUK_HOBJECT_E_GET_FLAGS_BASE(heap, h);
	n = DUK_HOBJECT_GET_ENEXT(h);
	while (n-- > 0) {
		duk_hstring *key;

		key = p_key[n];
		if (DUK_UNLIKELY(key == NULL)) {
			continue;
		}
		DUK_HSTRING_DECREF_NORZ(thr, key);
		if (DUK_UNLIKELY(p_flag[n] & DUK_PROPDESC_FLAG_ACCESSOR)) {
			duk_hobject *h_getset;
			h_getset = p_val[n].a.get;
			DUK_ASSERT(h_getset == NULL || DUK_HEAPHDR_IS_OBJECT((duk_heaphdr *) h_getset));
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, h_getset);
			h_getset = p_val[n].a.set;
			DUK_ASSERT(h_getset == NULL || DUK_HEAPHDR_IS_OBJECT((duk_heaphdr *) h_getset));
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, h_getset);
		} else {
			duk_tval *tv_val;
			tv_val = &p_val[n].v;
			DUK_TVAL_DECREF_NORZ(thr, tv_val);
		}
	}

	p_tv = DUK_HOBJECT_A_GET_BASE(heap, h);
	n = DUK_HOBJECT_GET_ASIZE(h);
	while (n-- > 0) {
		duk_tval *tv_val;
		tv_val = p_tv + n;
		DUK_TVAL_DECREF_NORZ(thr, tv_val);
	}

	/* Hash part is a 'weak reference' and doesn't contribute to refcounts. */

	h_proto = (duk_hobject *) DUK_HOBJECT_GET_PROTOTYPE(heap, h);
	DUK_ASSERT(h_proto == NULL || DUK_HEAPHDR_IS_OBJECT((duk_heaphdr *) h_proto));
	DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, h_proto);

	/* XXX: Object subclass tests are quite awkward at present, ideally
	 * we should be able to switch-case here with a dense index (subtype
	 * number or something).  For now, fast path plain objects and arrays
	 * and bit test the rest individually.
	 */

	if (DUK_HOBJECT_HAS_FASTREFS(h)) {
		/* Plain object or array, nothing more to do.  While a
		 * duk_harray has additional fields, none of them need
		 * DECREF updates.
		 */
		DUK_ASSERT(DUK_HOBJECT_ALLOWS_FASTREFS(h));
		return;
	}
	DUK_ASSERT(DUK_HOBJECT_PROHIBITS_FASTREFS(h));

	/* Slow path: special object, start bit checks from most likely. */

	/* XXX: reorg, more common first */
	if (DUK_HOBJECT_IS_COMPFUNC(h)) {
		duk_hcompfunc *f = (duk_hcompfunc *) h;
		duk_tval *tv, *tv_end;
		duk_hobject **funcs, **funcs_end;

		DUK_HCOMPFUNC_ASSERT_VALID(f);

		if (DUK_LIKELY(DUK_HCOMPFUNC_GET_DATA(heap, f) != NULL)) {
			tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(heap, f);
			tv_end = DUK_HCOMPFUNC_GET_CONSTS_END(heap, f);
			while (tv < tv_end) {
				DUK_TVAL_DECREF_NORZ(thr, tv);
				tv++;
			}

			funcs = DUK_HCOMPFUNC_GET_FUNCS_BASE(heap, f);
			funcs_end = DUK_HCOMPFUNC_GET_FUNCS_END(heap, f);
			while (funcs < funcs_end) {
				duk_hobject *h_func;
				h_func = *funcs;
				DUK_ASSERT(h_func != NULL);
				DUK_ASSERT(DUK_HEAPHDR_IS_OBJECT((duk_heaphdr *) h_func));
				DUK_HCOMPFUNC_DECREF_NORZ(thr, (duk_hcompfunc *) h_func);
				funcs++;
			}
		} else {
			/* May happen in some out-of-memory corner cases. */
			DUK_D(DUK_DPRINT("duk_hcompfunc 'data' is NULL, skipping decref"));
		}

		DUK_HEAPHDR_DECREF_ALLOWNULL(thr, (duk_heaphdr *) DUK_HCOMPFUNC_GET_LEXENV(heap, f));
		DUK_HEAPHDR_DECREF_ALLOWNULL(thr, (duk_heaphdr *) DUK_HCOMPFUNC_GET_VARENV(heap, f));
		DUK_HEAPHDR_DECREF_ALLOWNULL(thr, (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(heap, f));
	} else if (DUK_HOBJECT_IS_DECENV(h)) {
		duk_hdecenv *e = (duk_hdecenv *) h;
		DUK_HDECENV_ASSERT_VALID(e);
		DUK_HTHREAD_DECREF_NORZ_ALLOWNULL(thr, e->thread);
		DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, e->varmap);
	} else if (DUK_HOBJECT_IS_OBJENV(h)) {
		duk_hobjenv *e = (duk_hobjenv *) h;
		DUK_HOBJENV_ASSERT_VALID(e);
		DUK_ASSERT(e->target != NULL);  /* Required for object environments. */
		DUK_HOBJECT_DECREF_NORZ(thr, e->target);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	} else if (DUK_HOBJECT_IS_BUFOBJ(h)) {
		duk_hbufobj *b = (duk_hbufobj *) h;
		DUK_HBUFOBJ_ASSERT_VALID(b);
		DUK_HBUFFER_DECREF_NORZ_ALLOWNULL(thr, (duk_hbuffer *) b->buf);
		DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) b->buf_prop);
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */
	} else if (DUK_HOBJECT_IS_BOUNDFUNC(h)) {
		duk_hboundfunc *f = (duk_hboundfunc *) (void *) h;
		DUK_HBOUNDFUNC_ASSERT_VALID(f);
		DUK_TVAL_DECREF_NORZ(thr, &f->target);
		DUK_TVAL_DECREF_NORZ(thr, &f->this_binding);
		duk__decref_tvals_norz(thr, f->args, f->nargs);
#if defined(DUK_USE_ES6_PROXY)
	} else if (DUK_HOBJECT_IS_PROXY(h)) {
		duk_hproxy *p = (duk_hproxy *) h;
		DUK_HPROXY_ASSERT_VALID(p);
		DUK_HOBJECT_DECREF_NORZ(thr, p->target);
		DUK_HOBJECT_DECREF_NORZ(thr, p->handler);
#endif  /* DUK_USE_ES6_PROXY */
	} else if (DUK_HOBJECT_IS_THREAD(h)) {
		duk_hthread *t = (duk_hthread *) h;
		duk_activation *act;
		duk_tval *tv;

		DUK_HTHREAD_ASSERT_VALID(t);

		tv = t->valstack;
		while (tv < t->valstack_top) {
			DUK_TVAL_DECREF_NORZ(thr, tv);
			tv++;
		}

		for (act = t->callstack_curr; act != NULL; act = act->parent) {
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) DUK_ACT_GET_FUNC(act));
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) act->var_env);
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) act->lex_env);
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) act->prev_caller);
#endif
#if 0  /* nothing now */
			for (cat = act->cat; cat != NULL; cat = cat->parent) {
			}
#endif
		}


		for (i = 0; i < DUK_NUM_BUILTINS; i++) {
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, (duk_hobject *) t->builtins[i]);
		}

		DUK_HTHREAD_DECREF_NORZ_ALLOWNULL(thr, (duk_hthread *) t->resumer);
	} else {
		/* We may come here if the object should have a FASTREFS flag
		 * but it's missing for some reason.  Assert for never getting
		 * here; however, other than performance, this is harmless.
		 */
		DUK_D(DUK_DPRINT("missing FASTREFS flag for: %!iO", h));
		DUK_ASSERT(0);
	}
}

DUK_INTERNAL void duk_heaphdr_refcount_finalize_norz(duk_heap *heap, duk_heaphdr *hdr) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(hdr != NULL);

	if (DUK_HEAPHDR_IS_OBJECT(hdr)) {
		duk_hobject_refcount_finalize_norz(heap, (duk_hobject *) hdr);
	}
	/* DUK_HTYPE_BUFFER: nothing to finalize */
	/* DUK_HTYPE_STRING: nothing to finalize */
}

/*
 *  Refzero processing for duk_hobject: queue a refzero'ed object to either
 *  finalize_list or refzero_list and process the relevent list(s) if
 *  necessary.
 *
 *  Refzero_list is single linked, with only 'prev' pointers set and valid.
 *  All 'next' pointers are intentionally left as garbage.  This doesn't
 *  matter because refzero_list is processed to completion before any other
 *  code (like mark-and-sweep) might walk the list.
 *
 *  In more detail:
 *
 *  - On first insert refzero_list is NULL and the new object becomes the
 *    first and only element on the list; duk__refcount_free_pending() is
 *    called and it starts processing the list from the initial element,
 *    i.e. the list tail.
 *
 *  - As each object is refcount finalized, new objects may be queued to
 *    refzero_list head.  Their 'next' pointers are left as garbage, but
 *    'prev' points are set correctly, with the element at refzero_list
 *    having a NULL 'prev' pointer.  The fact that refzero_list is non-NULL
 *    is used to reject (1) recursive duk__refcount_free_pending() and
 *    (2) finalize_list processing calls.
 *
 *  - When we're done with the current object, read its 'prev' pointer and
 *    free the object.  If 'prev' is NULL, we've reached head of list and are
 *    done: set refzero_list to NULL and process pending finalizers.  Otherwise
 *    continue processing the list.
 *
 *  A refzero cascade is free of side effects because it only involves
 *  queueing more objects and freeing memory; finalizer execution is blocked
 *  in the code path queueing objects to finalize_list.  As a result the
 *  initial refzero call (which triggers duk__refcount_free_pending()) must
 *  check finalize_list so that finalizers are executed snappily.
 *
 *  If finalize_list processing starts first, refzero may occur while we're
 *  processing finalizers.  That's fine: that particular refzero cascade is
 *  handled to completion without side effects.  Once the cascade is complete,
 *  we'll run pending finalizers but notice that we're already doing that and
 *  return.
 *
 *  This could be expanded to allow incremental freeing: just bail out
 *  early and resume at a future alloc/decref/refzero.  However, if that
 *  were done, the list structure would need to be kept consistent at all
 *  times, mark-and-sweep would need to handle refzero_list, etc.
 */

DUK_LOCAL void duk__refcount_free_pending(duk_heap *heap) {
	duk_heaphdr *curr;
#if defined(DUK_USE_DEBUG)
	duk_int_t count = 0;
#endif

	DUK_ASSERT(heap != NULL);

	curr = heap->refzero_list;
	DUK_ASSERT(curr != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, curr) == NULL);  /* We're called on initial insert only. */
	/* curr->next is GARBAGE. */

	do {
		duk_heaphdr *prev;

		DUK_DDD(DUK_DDDPRINT("refzero processing %p: %!O", (void *) curr, (duk_heaphdr *) curr));

#if defined(DUK_USE_DEBUG)
		count++;
#endif

		DUK_ASSERT(curr != NULL);
		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);  /* currently, always the case */
		/* FINALIZED may be set; don't care about flags here. */

		/* Refcount finalize 'curr'.  Refzero_list must be non-NULL
		 * here to prevent recursive entry to duk__refcount_free_pending().
		 */
		DUK_ASSERT(heap->refzero_list != NULL);
		duk_hobject_refcount_finalize_norz(heap, (duk_hobject *) curr);

		prev = DUK_HEAPHDR_GET_PREV(heap, curr);
		DUK_ASSERT((prev == NULL && heap->refzero_list == curr) || \
		           (prev != NULL && heap->refzero_list != curr));
		/* prev->next is intentionally not updated and is garbage. */

		duk_free_hobject(heap, (duk_hobject *) curr);  /* Invalidates 'curr'. */

		curr = prev;
	} while (curr != NULL);

	heap->refzero_list = NULL;

	DUK_DD(DUK_DDPRINT("refzero processed %ld objects", (long) count));
}

DUK_LOCAL DUK_INLINE void duk__refcount_refzero_hobject(duk_heap *heap, duk_hobject *obj, duk_bool_t skip_free_pending) {
	duk_heaphdr *hdr;
	duk_heaphdr *root;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) obj) == DUK_HTYPE_OBJECT);

	hdr = (duk_heaphdr *) obj;

	/* Refzero'd objects must be in heap_allocated.  They can't be in
	 * finalize_list because all objects on finalize_list have an
	 * artificial +1 refcount bump.
	 */
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(duk_heap_in_heap_allocated(heap, (duk_heaphdr *) obj));
#endif

	DUK_HEAP_REMOVE_FROM_HEAP_ALLOCATED(heap, hdr);

#if defined(DUK_USE_FINALIZER_SUPPORT)
	/* This finalizer check MUST BE side effect free.  It should also be
	 * as fast as possible because it's applied to every object freed.
	 */
	if (DUK_UNLIKELY(DUK_HOBJECT_HAS_FINALIZER_FAST(heap, (duk_hobject *) hdr) != 0U)) {
		/* Special case: FINALIZED may be set if mark-and-sweep queued
		 * object for finalization, the finalizer was executed (and
		 * FINALIZED set), mark-and-sweep hasn't yet processed the
		 * object again, but its refcount drops to zero.  Free without
		 * running the finalizer again.
		 */
		if (DUK_HEAPHDR_HAS_FINALIZED(hdr)) {
			DUK_D(DUK_DPRINT("refzero'd object has finalizer and FINALIZED is set -> free"));
		} else {
			/* Set FINALIZABLE flag so that all objects on finalize_list
			 * will have it set and are thus detectable based on the
			 * flag alone.
			 */
			DUK_HEAPHDR_SET_FINALIZABLE(hdr);
			DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(hdr));

#if defined(DUK_USE_REFERENCE_COUNTING)
			/* Bump refcount on finalize_list insert so that a
			 * refzero can never occur when an object is waiting
			 * for its finalizer call.  Refzero might otherwise
			 * now happen because we allow duk_push_heapptr() for
			 * objects pending finalization.
			 */
			DUK_HEAPHDR_PREINC_REFCOUNT(hdr);
#endif
			DUK_HEAP_INSERT_INTO_FINALIZE_LIST(heap, hdr);

			/* Process finalizers unless skipping is explicitly
			 * requested (NORZ) or refzero_list is being processed
			 * (avoids side effects during a refzero cascade).
			 * If refzero_list is processed, the initial refzero
			 * call will run pending finalizers when refzero_list
			 * is done.
			 */
			if (!skip_free_pending && heap->refzero_list == NULL) {
				duk_heap_process_finalize_list(heap);
			}
			return;
		}
	}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

	/* No need to finalize, free object via refzero_list. */

	root = heap->refzero_list;

	DUK_HEAPHDR_SET_PREV(heap, hdr, NULL);
	/* 'next' is left as GARBAGE. */
	heap->refzero_list = hdr;

	if (root == NULL) {
		/* Object is now queued.  Refzero_list was NULL so
		 * no-one is currently processing it; do it here.
		 * With refzero processing just doing a cascade of
		 * free calls, we can process it directly even when
		 * NORZ macros are used: there are no side effects.
		 */
		duk__refcount_free_pending(heap);
		DUK_ASSERT(heap->refzero_list == NULL);

		/* Process finalizers only after the entire cascade
		 * is finished.  In most cases there's nothing to
		 * finalize, so fast path check to avoid a call.
		 */
#if defined(DUK_USE_FINALIZER_SUPPORT)
		if (!skip_free_pending && DUK_UNLIKELY(heap->finalize_list != NULL)) {
			duk_heap_process_finalize_list(heap);
		}
#endif
	} else {
		DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, root) == NULL);
		DUK_HEAPHDR_SET_PREV(heap, root, hdr);

		/* Object is now queued.  Because refzero_list was
		 * non-NULL, it's already being processed by someone
		 * in the C call stack, so we're done.
		 */
	}
}

#if defined(DUK_USE_FINALIZER_SUPPORT)
DUK_INTERNAL DUK_ALWAYS_INLINE void duk_refzero_check_fast(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->heap->refzero_list == NULL);  /* Processed to completion inline. */

	if (DUK_UNLIKELY(thr->heap->finalize_list != NULL)) {
		duk_heap_process_finalize_list(thr->heap);
	}
}

DUK_INTERNAL void duk_refzero_check_slow(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->heap->refzero_list == NULL);  /* Processed to completion inline. */

	if (DUK_UNLIKELY(thr->heap->finalize_list != NULL)) {
		duk_heap_process_finalize_list(thr->heap);
	}
}
#endif  /* DUK_USE_FINALIZER_SUPPORT */

/*
 *  Refzero processing for duk_hstring.
 */

DUK_LOCAL DUK_INLINE void duk__refcount_refzero_hstring(duk_heap *heap, duk_hstring *str) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(str != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) str) == DUK_HTYPE_STRING);

	duk_heap_strcache_string_remove(heap, str);
	duk_heap_strtable_unlink(heap, str);
	duk_free_hstring(heap, str);
}

/*
 *  Refzero processing for duk_hbuffer.
 */

DUK_LOCAL DUK_INLINE void duk__refcount_refzero_hbuffer(duk_heap *heap, duk_hbuffer *buf) {
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->heap_thread != NULL);
	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) buf) == DUK_HTYPE_BUFFER);

	DUK_HEAP_REMOVE_FROM_HEAP_ALLOCATED(heap, (duk_heaphdr *) buf);
	duk_free_hbuffer(heap, buf);
}

/*
 *  Incref and decref functions.
 *
 *  Decref may trigger immediate refzero handling, which may free and finalize
 *  an arbitrary number of objects (a "DECREF cascade").
 *
 *  Refzero handling is skipped entirely if (1) mark-and-sweep is running or
 *  (2) execution is paused in the debugger.  The objects are left in the heap,
 *  and will be freed by mark-and-sweep or eventual heap destruction.
 *
 *  This is necessary during mark-and-sweep because refcounts are also updated
 *  during the sweep phase (otherwise objects referenced by a swept object
 *  would have incorrect refcounts) which then calls here.  This could be
 *  avoided by using separate decref macros in mark-and-sweep; however,
 *  mark-and-sweep also calls finalizers which would use the ordinary decref
 *  macros anyway.
 *
 *  We can't process refzeros (= free objects) when the debugger is running
 *  as the debugger might make an object unreachable but still continue
 *  inspecting it (or even cause it to be pushed back).  So we must rely on
 *  mark-and-sweep to collect them.
 *
 *  The DUK__RZ_SUPPRESS_CHECK() condition is also used in heap destruction
 *  when running finalizers for remaining objects: the flag prevents objects
 *  from being moved around in heap linked lists while that's being done.
 *
 *  The suppress condition is important to performance.
 */

#define DUK__RZ_SUPPRESS_ASSERT1() do { \
		DUK_ASSERT(thr != NULL); \
		DUK_ASSERT(thr->heap != NULL); \
		/* When mark-and-sweep runs, heap_thread must exist. */ \
		DUK_ASSERT(thr->heap->ms_running == 0 || thr->heap->heap_thread != NULL); \
		/* In normal operation finalizers are executed with ms_running == 0 \
		 * so we should never see ms_running == 1 and thr != heap_thread. \
		 * In heap destruction finalizers are executed with ms_running != 0 \
		 * to e.g. prevent refzero; a special value ms_running == 2 is used \
		 * in that case so it can be distinguished from the normal runtime \
		 * case, and allows a stronger assertion here (GH-2030). \
		 */ \
		DUK_ASSERT(!(thr->heap->ms_running == 1 && thr != thr->heap->heap_thread)); \
		/* We may be called when the heap is initializing and we process \
		 * refzeros normally, but mark-and-sweep and finalizers are prevented \
		 * if that's the case. \
		 */ \
		DUK_ASSERT(thr->heap->heap_initializing == 0 || thr->heap->ms_prevent_count > 0); \
		DUK_ASSERT(thr->heap->heap_initializing == 0 || thr->heap->pf_prevent_count > 0); \
	} while (0)

#if defined(DUK_USE_DEBUGGER_SUPPORT)
#define DUK__RZ_SUPPRESS_ASSERT2() do { \
		/* When debugger is paused, ms_running is set. */ \
		DUK_ASSERT(!DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap) || thr->heap->ms_running != 0); \
	} while (0)
#define DUK__RZ_SUPPRESS_COND()  (heap->ms_running != 0)
#else
#define DUK__RZ_SUPPRESS_ASSERT2() do { } while (0)
#define DUK__RZ_SUPPRESS_COND()  (heap->ms_running != 0)
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

#define DUK__RZ_SUPPRESS_CHECK() do { \
		DUK__RZ_SUPPRESS_ASSERT1(); \
		DUK__RZ_SUPPRESS_ASSERT2(); \
		if (DUK_UNLIKELY(DUK__RZ_SUPPRESS_COND())) { \
			DUK_DDD(DUK_DDDPRINT("refzero handling suppressed (not even queued) when mark-and-sweep running, object: %p", (void *) h)); \
			return; \
		} \
	} while (0)

#define DUK__RZ_STRING() do { \
		duk__refcount_refzero_hstring(heap, (duk_hstring *) h); \
	} while (0)
#define DUK__RZ_BUFFER() do { \
		duk__refcount_refzero_hbuffer(heap, (duk_hbuffer *) h); \
	} while (0)
#define DUK__RZ_OBJECT() do { \
		duk__refcount_refzero_hobject(heap, (duk_hobject *) h, skip_free_pending); \
	} while (0)

/* XXX: test the effect of inlining here vs. NOINLINE in refzero helpers */
#if defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
#define DUK__RZ_INLINE DUK_ALWAYS_INLINE
#else
#define DUK__RZ_INLINE /*nop*/
#endif

DUK_LOCAL DUK__RZ_INLINE void duk__hstring_refzero_helper(duk_hthread *thr, duk_hstring *h) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	heap = thr->heap;

	DUK__RZ_SUPPRESS_CHECK();
	DUK__RZ_STRING();
}

DUK_LOCAL DUK__RZ_INLINE void duk__hbuffer_refzero_helper(duk_hthread *thr, duk_hbuffer *h) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	heap = thr->heap;

	DUK__RZ_SUPPRESS_CHECK();
	DUK__RZ_BUFFER();
}

DUK_LOCAL DUK__RZ_INLINE void duk__hobject_refzero_helper(duk_hthread *thr, duk_hobject *h, duk_bool_t skip_free_pending) {
	duk_heap *heap;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	heap = thr->heap;

	DUK__RZ_SUPPRESS_CHECK();
	DUK__RZ_OBJECT();
}

DUK_LOCAL DUK__RZ_INLINE void duk__heaphdr_refzero_helper(duk_hthread *thr, duk_heaphdr *h, duk_bool_t skip_free_pending) {
	duk_heap *heap;
	duk_small_uint_t htype;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	heap = thr->heap;

	htype = (duk_small_uint_t) DUK_HEAPHDR_GET_TYPE(h);
	DUK_DDD(DUK_DDDPRINT("ms_running=%ld, heap_thread=%p", (long) thr->heap->ms_running, thr->heap->heap_thread));
	DUK__RZ_SUPPRESS_CHECK();

	switch (htype) {
	case DUK_HTYPE_STRING:
		/* Strings have no internal references but do have "weak"
		 * references in the string cache.  Also note that strings
		 * are not on the heap_allocated list like other heap
		 * elements.
		 */

		DUK__RZ_STRING();
		break;

	case DUK_HTYPE_OBJECT:
		/* Objects have internal references.  Must finalize through
		 * the "refzero" work list.
		 */

		DUK__RZ_OBJECT();
		break;

	default:
		/* Buffers have no internal references.  However, a dynamic
		 * buffer has a separate allocation for the buffer.  This is
		 * freed by duk_heap_free_heaphdr_raw().
		 */

		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(h) == DUK_HTYPE_BUFFER);
		DUK__RZ_BUFFER();
		break;
	}
}

DUK_INTERNAL DUK_NOINLINE void duk_heaphdr_refzero(duk_hthread *thr, duk_heaphdr *h) {
	duk__heaphdr_refzero_helper(thr, h, 0 /*skip_free_pending*/);
}

DUK_INTERNAL DUK_NOINLINE void duk_heaphdr_refzero_norz(duk_hthread *thr, duk_heaphdr *h) {
	duk__heaphdr_refzero_helper(thr, h, 1 /*skip_free_pending*/);
}

DUK_INTERNAL DUK_NOINLINE void duk_hstring_refzero(duk_hthread *thr, duk_hstring *h) {
	duk__hstring_refzero_helper(thr, h);
}

DUK_INTERNAL DUK_NOINLINE void duk_hbuffer_refzero(duk_hthread *thr, duk_hbuffer *h) {
	duk__hbuffer_refzero_helper(thr, h);
}

DUK_INTERNAL DUK_NOINLINE void duk_hobject_refzero(duk_hthread *thr, duk_hobject *h) {
	duk__hobject_refzero_helper(thr, h, 0 /*skip_free_pending*/);
}

DUK_INTERNAL DUK_NOINLINE void duk_hobject_refzero_norz(duk_hthread *thr, duk_hobject *h) {
	duk__hobject_refzero_helper(thr, h, 1 /*skip_free_pending*/);
}

#if !defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
DUK_INTERNAL void duk_tval_incref(duk_tval *tv) {
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
		DUK_ASSERT_DISABLE(h->h_refcount >= 0);
		DUK_HEAPHDR_PREINC_REFCOUNT(h);
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(h) != 0);  /* No wrapping. */
	}
}

DUK_INTERNAL void duk_tval_decref(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(h) >= 1);
#if 0
		if (DUK_HEAPHDR_PREDEC_REFCOUNT(h) != 0) {
			return;
		}
		duk_heaphdr_refzero(thr, h);
#else
		duk_heaphdr_decref(thr, h);
#endif
	}
}

DUK_INTERNAL void duk_tval_decref_norz(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(h) >= 1);
#if 0
		if (DUK_HEAPHDR_PREDEC_REFCOUNT(h) != 0) {
			return;
		}
		duk_heaphdr_refzero_norz(thr, h);
#else
		duk_heaphdr_decref_norz(thr, h);
#endif
	}
}
#endif  /* !DUK_USE_FAST_REFCOUNT_DEFAULT */

#define DUK__DECREF_ASSERTS() do { \
		DUK_ASSERT(thr != NULL); \
		DUK_ASSERT(thr->heap != NULL); \
		DUK_ASSERT(h != NULL); \
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID((duk_heaphdr *) h)); \
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) >= 1); \
	} while (0)
#if defined(DUK_USE_ROM_OBJECTS)
#define DUK__INCREF_SHARED() do { \
		if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h)) { \
			return; \
		} \
		DUK_HEAPHDR_PREINC_REFCOUNT((duk_heaphdr *) h); \
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) != 0);  /* No wrapping. */ \
	} while (0)
#define DUK__DECREF_SHARED() do { \
		if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h)) { \
			return; \
		} \
		if (DUK_HEAPHDR_PREDEC_REFCOUNT((duk_heaphdr *) h) != 0) { \
			return; \
		} \
	} while (0)
#else
#define DUK__INCREF_SHARED() do { \
		DUK_HEAPHDR_PREINC_REFCOUNT((duk_heaphdr *) h); \
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) != 0);  /* No wrapping. */ \
	} while (0)
#define DUK__DECREF_SHARED() do { \
		if (DUK_HEAPHDR_PREDEC_REFCOUNT((duk_heaphdr *) h) != 0) { \
			return; \
		} \
	} while (0)
#endif

#if !defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
/* This will in practice be inlined because it's just an INC instructions
 * and a bit test + INC when ROM objects are enabled.
 */
DUK_INTERNAL void duk_heaphdr_incref(duk_heaphdr *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);

	DUK__INCREF_SHARED();
}

DUK_INTERNAL void duk_heaphdr_decref(duk_hthread *thr, duk_heaphdr *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_heaphdr_refzero(thr, h);

	/* Forced mark-and-sweep when GC torture enabled; this could happen
	 * on any DECREF (but not DECREF_NORZ).
	 */
	DUK_GC_TORTURE(thr->heap);
}
DUK_INTERNAL void duk_heaphdr_decref_norz(duk_hthread *thr, duk_heaphdr *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_heaphdr_refzero_norz(thr, h);
}
#endif  /* !DUK_USE_FAST_REFCOUNT_DEFAULT */

#if 0  /* Not needed. */
DUK_INTERNAL void duk_hstring_decref(duk_hthread *thr, duk_hstring *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hstring_refzero(thr, h);
}
DUK_INTERNAL void duk_hstring_decref_norz(duk_hthread *thr, duk_hstring *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hstring_refzero_norz(thr, h);
}
DUK_INTERNAL void duk_hbuffer_decref(duk_hthread *thr, duk_hbuffer *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hbuffer_refzero(thr, h);
}
DUK_INTERNAL void duk_hbuffer_decref_norz(duk_hthread *thr, duk_hbuffer *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hbuffer_refzero_norz(thr, h);
}
DUK_INTERNAL void duk_hobject_decref(duk_hthread *thr, duk_hobject *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hobject_refzero(thr, h);
}
DUK_INTERNAL void duk_hobject_decref_norz(duk_hthread *thr, duk_hobject *h) {
	DUK__DECREF_ASSERTS();
	DUK__DECREF_SHARED();
	duk_hobject_refzero_norz(thr, h);
}
#endif

#else  /* DUK_USE_REFERENCE_COUNTING */

/* no refcounting */

#endif  /* DUK_USE_REFERENCE_COUNTING */

/* automatic undefs */
#undef DUK__DECREF_ASSERTS
#undef DUK__DECREF_SHARED
#undef DUK__INCREF_SHARED
#undef DUK__RZ_BUFFER
#undef DUK__RZ_INLINE
#undef DUK__RZ_OBJECT
#undef DUK__RZ_STRING
#undef DUK__RZ_SUPPRESS_ASSERT1
#undef DUK__RZ_SUPPRESS_ASSERT2
#undef DUK__RZ_SUPPRESS_CHECK
#undef DUK__RZ_SUPPRESS_COND
/*
 *  String cache.
 *
 *  Provides a cache to optimize indexed string lookups.  The cache keeps
 *  track of (byte offset, char offset) states for a fixed number of strings.
 *  Otherwise we'd need to scan from either end of the string, as we store
 *  strings in (extended) UTF-8.
 */

/* #include duk_internal.h -> already included */

/*
 *  Delete references to given hstring from the heap string cache.
 *
 *  String cache references are 'weak': they are not counted towards
 *  reference counts, nor serve as roots for mark-and-sweep.  When an
 *  object is about to be freed, such references need to be removed.
 */

DUK_INTERNAL void duk_heap_strcache_string_remove(duk_heap *heap, duk_hstring *h) {
	duk_uint_t i;
	for (i = 0; i < DUK_HEAP_STRCACHE_SIZE; i++) {
		duk_strcache_entry *c = heap->strcache + i;
		if (c->h == h) {
			DUK_DD(DUK_DDPRINT("deleting weak strcache reference to hstring %p from heap %p",
			                   (void *) h, (void *) heap));
			c->h = NULL;

			/* XXX: the string shouldn't appear twice, but we now loop to the
			 * end anyway; if fixed, add a looping assertion to ensure there
			 * is no duplicate.
			 */
		}
	}
}

/*
 *  String scanning helpers
 *
 *  All bytes other than UTF-8 continuation bytes ([0x80,0xbf]) are
 *  considered to contribute a character.  This must match how string
 *  character length is computed.
 */

DUK_LOCAL const duk_uint8_t *duk__scan_forwards(const duk_uint8_t *p, const duk_uint8_t *q, duk_uint_fast32_t n) {
	while (n > 0) {
		for (;;) {
			p++;
			if (p >= q) {
				return NULL;
			}
			if ((*p & 0xc0) != 0x80) {
				break;
			}
		}
		n--;
	}
	return p;
}

DUK_LOCAL const duk_uint8_t *duk__scan_backwards(const duk_uint8_t *p, const duk_uint8_t *q, duk_uint_fast32_t n) {
	while (n > 0) {
		for (;;) {
			p--;
			if (p < q) {
				return NULL;
			}
			if ((*p & 0xc0) != 0x80) {
				break;
			}
		}
		n--;
	}
	return p;
}

/*
 *  Convert char offset to byte offset
 *
 *  Avoid using the string cache if possible: for ASCII strings byte and
 *  char offsets are equal and for short strings direct scanning may be
 *  better than using the string cache (which may evict a more important
 *  entry).
 *
 *  Typing now assumes 32-bit string byte/char offsets (duk_uint_fast32_t).
 *  Better typing might be to use duk_size_t.
 *
 *  Caller should ensure 'char_offset' is within the string bounds [0,charlen]
 *  (endpoint is inclusive).  If this is not the case, no memory unsafe
 *  behavior will happen but an error will be thrown.
 */

DUK_INTERNAL duk_uint_fast32_t duk_heap_strcache_offset_char2byte(duk_hthread *thr, duk_hstring *h, duk_uint_fast32_t char_offset) {
	duk_heap *heap;
	duk_strcache_entry *sce;
	duk_uint_fast32_t byte_offset;
	duk_uint_t i;
	duk_bool_t use_cache;
	duk_uint_fast32_t dist_start, dist_end, dist_sce;
	duk_uint_fast32_t char_length;
	const duk_uint8_t *p_start;
	const duk_uint8_t *p_end;
	const duk_uint8_t *p_found;

	/*
	 *  For ASCII strings, the answer is simple.
	 */

	if (DUK_LIKELY(DUK_HSTRING_IS_ASCII(h))) {
		return char_offset;
	}

	char_length = (duk_uint_fast32_t) DUK_HSTRING_GET_CHARLEN(h);
	DUK_ASSERT(char_offset <= char_length);

	if (DUK_LIKELY(DUK_HSTRING_IS_ASCII(h))) {
		/* Must recheck because the 'is ascii' flag may be set
		 * lazily.  Alternatively, we could just compare charlen
		 * to bytelen.
		 */
		return char_offset;
	}

	/*
	 *  For non-ASCII strings, we need to scan forwards or backwards
	 *  from some starting point.  The starting point may be the start
	 *  or end of the string, or some cached midpoint in the string
	 *  cache.
	 *
	 *  For "short" strings we simply scan without checking or updating
	 *  the cache.  For longer strings we check and update the cache as
	 *  necessary, inserting a new cache entry if none exists.
	 */

	DUK_DDD(DUK_DDDPRINT("non-ascii string %p, char_offset=%ld, clen=%ld, blen=%ld",
	                     (void *) h, (long) char_offset,
	                     (long) DUK_HSTRING_GET_CHARLEN(h),
	                     (long) DUK_HSTRING_GET_BYTELEN(h)));

	heap = thr->heap;
	sce = NULL;
	use_cache = (char_length > DUK_HEAP_STRINGCACHE_NOCACHE_LIMIT);

	if (use_cache) {
#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
		DUK_DDD(DUK_DDDPRINT("stringcache before char2byte (using cache):"));
		for (i = 0; i < DUK_HEAP_STRCACHE_SIZE; i++) {
			duk_strcache_entry *c = heap->strcache + i;
			DUK_DDD(DUK_DDDPRINT("  [%ld] -> h=%p, cidx=%ld, bidx=%ld",
			                     (long) i, (void *) c->h, (long) c->cidx, (long) c->bidx));
		}
#endif

		for (i = 0; i < DUK_HEAP_STRCACHE_SIZE; i++) {
			duk_strcache_entry *c = heap->strcache + i;

			if (c->h == h) {
				sce = c;
				break;
			}
		}
	}

	/*
	 *  Scan from shortest distance:
	 *    - start of string
	 *    - end of string
	 *    - cache entry (if exists)
	 */

	DUK_ASSERT(DUK_HSTRING_GET_CHARLEN(h) >= char_offset);
	dist_start = char_offset;
	dist_end = char_length - char_offset;
	dist_sce = 0; DUK_UNREF(dist_sce);  /* initialize for debug prints, needed if sce==NULL */

	p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	p_end = (const duk_uint8_t *) (p_start + DUK_HSTRING_GET_BYTELEN(h));
	p_found = NULL;

	if (sce) {
		if (char_offset >= sce->cidx) {
			dist_sce = char_offset - sce->cidx;
			if ((dist_sce <= dist_start) && (dist_sce <= dist_end)) {
				DUK_DDD(DUK_DDDPRINT("non-ascii string, use_cache=%ld, sce=%p:%ld:%ld, "
				                     "dist_start=%ld, dist_end=%ld, dist_sce=%ld => "
				                     "scan forwards from sce",
				                     (long) use_cache, (void *) (sce ? sce->h : NULL),
				                     (sce ? (long) sce->cidx : (long) -1),
				                     (sce ? (long) sce->bidx : (long) -1),
				                     (long) dist_start, (long) dist_end, (long) dist_sce));

				p_found = duk__scan_forwards(p_start + sce->bidx,
				                             p_end,
				                             dist_sce);
				goto scan_done;
			}
		} else {
			dist_sce = sce->cidx - char_offset;
			if ((dist_sce <= dist_start) && (dist_sce <= dist_end)) {
				DUK_DDD(DUK_DDDPRINT("non-ascii string, use_cache=%ld, sce=%p:%ld:%ld, "
				                     "dist_start=%ld, dist_end=%ld, dist_sce=%ld => "
				                     "scan backwards from sce",
				                     (long) use_cache, (void *) (sce ? sce->h : NULL),
				                     (sce ? (long) sce->cidx : (long) -1),
				                     (sce ? (long) sce->bidx : (long) -1),
				                     (long) dist_start, (long) dist_end, (long) dist_sce));

				p_found = duk__scan_backwards(p_start + sce->bidx,
				                              p_start,
				                              dist_sce);
				goto scan_done;
			}
		}
	}

	/* no sce, or sce scan not best */

	if (dist_start <= dist_end) {
		DUK_DDD(DUK_DDDPRINT("non-ascii string, use_cache=%ld, sce=%p:%ld:%ld, "
		                     "dist_start=%ld, dist_end=%ld, dist_sce=%ld => "
		                     "scan forwards from string start",
		                     (long) use_cache, (void *) (sce ? sce->h : NULL),
		                     (sce ? (long) sce->cidx : (long) -1),
		                     (sce ? (long) sce->bidx : (long) -1),
		                     (long) dist_start, (long) dist_end, (long) dist_sce));

		p_found = duk__scan_forwards(p_start,
		                             p_end,
		                             dist_start);
	} else {
		DUK_DDD(DUK_DDDPRINT("non-ascii string, use_cache=%ld, sce=%p:%ld:%ld, "
		                     "dist_start=%ld, dist_end=%ld, dist_sce=%ld => "
		                     "scan backwards from string end",
		                     (long) use_cache, (void *) (sce ? sce->h : NULL),
		                     (sce ? (long) sce->cidx : (long) -1),
		                     (sce ? (long) sce->bidx : (long) -1),
		                     (long) dist_start, (long) dist_end, (long) dist_sce));

		p_found = duk__scan_backwards(p_end,
		                              p_start,
		                              dist_end);
	}

 scan_done:

	if (DUK_UNLIKELY(p_found == NULL)) {
		/* Scan error: this shouldn't normally happen; it could happen if
		 * string is not valid UTF-8 data, and clen/blen are not consistent
		 * with the scanning algorithm.
		 */
		goto scan_error;
	}

	DUK_ASSERT(p_found >= p_start);
	DUK_ASSERT(p_found <= p_end);  /* may be equal */
	byte_offset = (duk_uint32_t) (p_found - p_start);

	DUK_DDD(DUK_DDDPRINT("-> string %p, cidx %ld -> bidx %ld",
	                     (void *) h, (long) char_offset, (long) byte_offset));

	/*
	 *  Update cache entry (allocating if necessary), and move the
	 *  cache entry to the first place (in an "LRU" policy).
	 */

	if (use_cache) {
		/* update entry, allocating if necessary */
		if (!sce) {
			sce = heap->strcache + DUK_HEAP_STRCACHE_SIZE - 1;  /* take last entry */
			sce->h = h;
		}
		DUK_ASSERT(sce != NULL);
		sce->bidx = (duk_uint32_t) (p_found - p_start);
		sce->cidx = (duk_uint32_t) char_offset;

		/* LRU: move our entry to first */
		if (sce > &heap->strcache[0]) {
			/*
			 *   A                  C
			 *   B                  A
			 *   C <- sce    ==>    B
			 *   D                  D
			 */
			duk_strcache_entry tmp;

			tmp = *sce;
			duk_memmove((void *) (&heap->strcache[1]),
			            (const void *) (&heap->strcache[0]),
			            (size_t) (((char *) sce) - ((char *) &heap->strcache[0])));
			heap->strcache[0] = tmp;

			/* 'sce' points to the wrong entry here, but is no longer used */
		}
#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
		DUK_DDD(DUK_DDDPRINT("stringcache after char2byte (using cache):"));
		for (i = 0; i < DUK_HEAP_STRCACHE_SIZE; i++) {
			duk_strcache_entry *c = heap->strcache + i;
			DUK_DDD(DUK_DDDPRINT("  [%ld] -> h=%p, cidx=%ld, bidx=%ld",
			                     (long) i, (void *) c->h, (long) c->cidx, (long) c->bidx));
		}
#endif
	}

	return byte_offset;

 scan_error:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return 0;);
}
/*
 *  Heap string table handling, string interning.
 */

/* #include duk_internal.h -> already included */

/* Resize checks not needed if minsize == maxsize, typical for low memory
 * targets.
 */
#define DUK__STRTAB_RESIZE_CHECK
#if (DUK_USE_STRTAB_MINSIZE == DUK_USE_STRTAB_MAXSIZE)
#undef DUK__STRTAB_RESIZE_CHECK
#endif

#if defined(DUK_USE_STRTAB_PTRCOMP)
#define DUK__HEAPPTR_ENC16(heap,ptr)    DUK_USE_HEAPPTR_ENC16((heap)->heap_udata, (ptr))
#define DUK__HEAPPTR_DEC16(heap,val)    DUK_USE_HEAPPTR_DEC16((heap)->heap_udata, (val))
#define DUK__GET_STRTABLE(heap)         ((heap)->strtable16)
#else
#define DUK__HEAPPTR_ENC16(heap,ptr)    (ptr)
#define DUK__HEAPPTR_DEC16(heap,val)    (val)
#define DUK__GET_STRTABLE(heap)         ((heap)->strtable)
#endif

#define DUK__STRTAB_U32_MAX_STRLEN      10               /* 4'294'967'295 */

/*
 *  Debug dump stringtable.
 */

#if defined(DUK_USE_DEBUG)
DUK_INTERNAL void duk_heap_strtable_dump(duk_heap *heap) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *strtable;
#else
	duk_hstring **strtable;
#endif
	duk_uint32_t i;
	duk_hstring *h;
	duk_size_t count_total = 0;
	duk_size_t count_chain;
	duk_size_t count_chain_min = DUK_SIZE_MAX;
	duk_size_t count_chain_max = 0;
	duk_size_t count_len[8];  /* chain lengths from 0 to 7 */

	if (heap == NULL) {
		DUK_D(DUK_DPRINT("string table, heap=NULL"));
		return;
	}

	strtable = DUK__GET_STRTABLE(heap);
	if (strtable == NULL) {
		DUK_D(DUK_DPRINT("string table, strtab=NULL"));
		return;
	}

	duk_memzero((void *) count_len, sizeof(count_len));
	for (i = 0; i < heap->st_size; i++) {
		h = DUK__HEAPPTR_DEC16(heap, strtable[i]);
		count_chain = 0;
		while (h != NULL) {
			count_chain++;
			h = h->hdr.h_next;
		}
		if (count_chain < sizeof(count_len) / sizeof(duk_size_t)) {
			count_len[count_chain]++;
		}
		count_chain_max = (count_chain > count_chain_max ? count_chain : count_chain_max);
		count_chain_min = (count_chain < count_chain_min ? count_chain : count_chain_min);
		count_total += count_chain;
	}

	DUK_D(DUK_DPRINT("string table, strtab=%p, count=%lu, chain min=%lu max=%lu avg=%lf: "
	                 "counts: %lu %lu %lu %lu %lu %lu %lu %lu ...",
	                 (void *) heap->strtable, (unsigned long) count_total,
	                 (unsigned long) count_chain_min, (unsigned long) count_chain_max,
	                 (double) count_total / (double) heap->st_size,
	                 (unsigned long) count_len[0], (unsigned long) count_len[1],
	                 (unsigned long) count_len[2], (unsigned long) count_len[3],
	                 (unsigned long) count_len[4], (unsigned long) count_len[5],
	                 (unsigned long) count_len[6], (unsigned long) count_len[7]));
}
#endif  /* DUK_USE_DEBUG */

/*
 *  Assertion helper to ensure strtable is populated correctly.
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_LOCAL void duk__strtable_assert_checks(duk_heap *heap) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *strtable;
#else
	duk_hstring **strtable;
#endif
	duk_uint32_t i;
	duk_hstring *h;
	duk_size_t count = 0;

	DUK_ASSERT(heap != NULL);

	strtable = DUK__GET_STRTABLE(heap);
	if (strtable != NULL) {
		DUK_ASSERT(heap->st_size != 0);
		DUK_ASSERT(heap->st_mask == heap->st_size - 1);

		for (i = 0; i < heap->st_size; i++) {
			h = DUK__HEAPPTR_DEC16(heap, strtable[i]);
			while (h != NULL) {
				DUK_ASSERT((DUK_HSTRING_GET_HASH(h) & heap->st_mask) == i);
				count++;
				h = h->hdr.h_next;
			}
		}
	} else {
		DUK_ASSERT(heap->st_size == 0);
		DUK_ASSERT(heap->st_mask == 0);
	}

#if defined(DUK__STRTAB_RESIZE_CHECK)
	DUK_ASSERT(count == (duk_size_t) heap->st_count);
#endif
}
#endif  /* DUK_USE_ASSERTIONS */

/*
 *  Allocate and initialize a duk_hstring.
 *
 *  Returns a NULL if allocation or initialization fails for some reason.
 *
 *  The string won't be inserted into the string table and isn't tracked in
 *  any way (link pointers will be NULL).  The caller must place the string
 *  into the string table without any risk of a longjmp, otherwise the string
 *  is leaked.
 */

DUK_LOCAL duk_hstring *duk__strtable_alloc_hstring(duk_heap *heap,
                                                   const duk_uint8_t *str,
                                                   duk_uint32_t blen,
                                                   duk_uint32_t strhash,
                                                   const duk_uint8_t *extdata) {
	duk_hstring *res;
	const duk_uint8_t *data;
#if !defined(DUK_USE_HSTRING_ARRIDX)
	duk_uarridx_t dummy;
#endif

	DUK_ASSERT(heap != NULL);
	DUK_UNREF(extdata);

#if defined(DUK_USE_STRLEN16)
	/* If blen <= 0xffffUL, clen is also guaranteed to be <= 0xffffUL. */
	if (blen > 0xffffUL) {
		DUK_D(DUK_DPRINT("16-bit string blen/clen active and blen over 16 bits, reject intern"));
		goto alloc_error;
	}
#endif

	/* XXX: Memzeroing the allocated structure is not really necessary
	 * because we could just initialize all fields explicitly (almost
	 * all fields are initialized explicitly anyway).
	 */
#if defined(DUK_USE_HSTRING_EXTDATA) && defined(DUK_USE_EXTSTR_INTERN_CHECK)
	if (extdata) {
		res = (duk_hstring *) DUK_ALLOC(heap, sizeof(duk_hstring_external));
		if (DUK_UNLIKELY(res == NULL)) {
			goto alloc_error;
		}
		duk_memzero(res, sizeof(duk_hstring_external));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
		DUK_HEAPHDR_STRING_INIT_NULLS(&res->hdr);
#endif
		DUK_HEAPHDR_SET_TYPE_AND_FLAGS(&res->hdr, DUK_HTYPE_STRING, DUK_HSTRING_FLAG_EXTDATA);

		DUK_ASSERT(extdata[blen] == 0);  /* Application responsibility. */
		data = extdata;
		((duk_hstring_external *) res)->extdata = extdata;
	} else
#endif  /* DUK_USE_HSTRING_EXTDATA && DUK_USE_EXTSTR_INTERN_CHECK */
	{
		duk_uint8_t *data_tmp;

		/* NUL terminate for convenient C access */
		DUK_ASSERT(sizeof(duk_hstring) + blen + 1 > blen);  /* No wrap, limits ensure. */
		res = (duk_hstring *) DUK_ALLOC(heap, sizeof(duk_hstring) + blen + 1);
		if (DUK_UNLIKELY(res == NULL)) {
			goto alloc_error;
		}
		duk_memzero(res, sizeof(duk_hstring));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
		DUK_HEAPHDR_STRING_INIT_NULLS(&res->hdr);
#endif
		DUK_HEAPHDR_SET_TYPE_AND_FLAGS(&res->hdr, DUK_HTYPE_STRING, 0);

		data_tmp = (duk_uint8_t *) (res + 1);
		duk_memcpy(data_tmp, str, blen);
		data_tmp[blen] = (duk_uint8_t) 0;
		data = (const duk_uint8_t *) data_tmp;
	}

	DUK_HSTRING_SET_BYTELEN(res, blen);
	DUK_HSTRING_SET_HASH(res, strhash);

	DUK_ASSERT(!DUK_HSTRING_HAS_ARRIDX(res));
#if defined(DUK_USE_HSTRING_ARRIDX)
	res->arridx = duk_js_to_arrayindex_string(data, blen);
	if (res->arridx != DUK_HSTRING_NO_ARRAY_INDEX) {
#else
	dummy = duk_js_to_arrayindex_string(data, blen);
	if (dummy != DUK_HSTRING_NO_ARRAY_INDEX) {
#endif
		/* Array index strings cannot be symbol strings,
		 * and they're always pure ASCII so blen == clen.
		 */
		DUK_HSTRING_SET_ARRIDX(res);
		DUK_HSTRING_SET_ASCII(res);
		DUK_ASSERT(duk_unicode_unvalidated_utf8_length(data, (duk_size_t) blen) == blen);
	} else {
		/* Because 'data' is NUL-terminated, we don't need a
		 * blen > 0 check here.  For NUL (0x00) the symbol
		 * checks will be false.
		 */
		if (DUK_UNLIKELY(data[0] >= 0x80U)) {
			if (data[0] <= 0x81) {
				DUK_HSTRING_SET_SYMBOL(res);
			} else if (data[0] == 0x82U || data[0] == 0xffU) {
				DUK_HSTRING_SET_HIDDEN(res);
				DUK_HSTRING_SET_SYMBOL(res);
			}
		}

		/* Using an explicit 'ASCII' flag has larger footprint (one call site
		 * only) but is quite useful for the case when there's no explicit
		 * 'clen' in duk_hstring.
		 *
		 * The flag is set lazily for RAM strings.
		 */
		DUK_ASSERT(!DUK_HSTRING_HAS_ASCII(res));

#if defined(DUK_USE_HSTRING_LAZY_CLEN)
		/* Charlen initialized to 0, updated on-the-fly. */
#else
		duk_hstring_init_charlen(res);  /* Also sets ASCII flag. */
#endif
	}

	DUK_DDD(DUK_DDDPRINT("interned string, hash=0x%08lx, blen=%ld, has_arridx=%ld, has_extdata=%ld",
	                     (unsigned long) DUK_HSTRING_GET_HASH(res),
	                     (long) DUK_HSTRING_GET_BYTELEN(res),
	                     (long) (DUK_HSTRING_HAS_ARRIDX(res) ? 1 : 0),
	                     (long) (DUK_HSTRING_HAS_EXTDATA(res) ? 1 : 0)));

	DUK_ASSERT(res != NULL);
	return res;

 alloc_error:
	return NULL;
}

/*
 *  Grow strtable allocation in-place.
 */

#if defined(DUK__STRTAB_RESIZE_CHECK)
DUK_LOCAL void duk__strtable_grow_inplace(duk_heap *heap) {
	duk_uint32_t new_st_size;
	duk_uint32_t old_st_size;
	duk_uint32_t i;
	duk_hstring *h;
	duk_hstring *next;
	duk_hstring *prev;
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *new_ptr;
	duk_uint16_t *new_ptr_high;
#else
	duk_hstring **new_ptr;
	duk_hstring **new_ptr_high;
#endif

	DUK_DD(DUK_DDPRINT("grow in-place: %lu -> %lu", (unsigned long) heap->st_size, (unsigned long) heap->st_size * 2));

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->st_resizing == 1);
	DUK_ASSERT(heap->st_size >= 2);
	DUK_ASSERT((heap->st_size & (heap->st_size - 1)) == 0);  /* 2^N */
	DUK_ASSERT(DUK__GET_STRTABLE(heap) != NULL);

	DUK_STATS_INC(heap, stats_strtab_resize_grow);

	new_st_size = heap->st_size << 1U;
	DUK_ASSERT(new_st_size > heap->st_size);  /* No overflow. */

	/* Reallocate the strtable first and then work in-place to rehash
	 * strings.  We don't need an indirect allocation here: even if GC
	 * is triggered to satisfy the allocation, recursive strtable resize
	 * is prevented by flags.  This is also why we don't need to use
	 * DUK_REALLOC_INDIRECT().
	 */

#if defined(DUK_USE_STRTAB_PTRCOMP)
	new_ptr = (duk_uint16_t *) DUK_REALLOC(heap, heap->strtable16, sizeof(duk_uint16_t) * new_st_size);
#else
	new_ptr = (duk_hstring **) DUK_REALLOC(heap, heap->strtable, sizeof(duk_hstring *) * new_st_size);
#endif
	if (DUK_UNLIKELY(new_ptr == NULL)) {
		/* If realloc fails we can continue normally: the string table
		 * won't "fill up" although chains will gradually get longer.
		 * When string insertions continue, we'll quite soon try again
		 * with no special handling.
		 */
		DUK_D(DUK_DPRINT("string table grow failed, ignoring"));
		return;
	}
#if defined(DUK_USE_STRTAB_PTRCOMP)
	heap->strtable16 = new_ptr;
#else
	heap->strtable = new_ptr;
#endif

	/* Rehash a single bucket into two separate ones.  When we grow
	 * by x2 the highest 'new' bit determines whether a string remains
	 * in its old position (bit is 0) or goes to a new one (bit is 1).
	 */

	old_st_size = heap->st_size;
	new_ptr_high = new_ptr + old_st_size;
	for (i = 0; i < old_st_size; i++) {
		duk_hstring *new_root;
		duk_hstring *new_root_high;

		h = DUK__HEAPPTR_DEC16(heap, new_ptr[i]);
		new_root = h;
		new_root_high = NULL;

		prev = NULL;
		while (h != NULL) {
			duk_uint32_t mask;

			DUK_ASSERT((DUK_HSTRING_GET_HASH(h) & heap->st_mask) == i);
			next = h->hdr.h_next;

			/* Example: if previous size was 256, previous mask is 0xFF
			 * and size is 0x100 which corresponds to the new bit that
			 * comes into play.
			 */
			DUK_ASSERT(heap->st_mask == old_st_size - 1);
			mask = old_st_size;
			if (DUK_HSTRING_GET_HASH(h) & mask) {
				if (prev != NULL) {
					prev->hdr.h_next = h->hdr.h_next;
				} else {
					DUK_ASSERT(h == new_root);
					new_root = h->hdr.h_next;
				}

				h->hdr.h_next = new_root_high;
				new_root_high = h;
			} else {
				prev = h;
			}
			h = next;
		}

		new_ptr[i] = DUK__HEAPPTR_ENC16(heap, new_root);
		new_ptr_high[i] = DUK__HEAPPTR_ENC16(heap, new_root_high);
	}

	heap->st_size = new_st_size;
	heap->st_mask = new_st_size - 1;

#if defined(DUK_USE_ASSERTIONS)
	duk__strtable_assert_checks(heap);
#endif
}
#endif  /* DUK__STRTAB_RESIZE_CHECK */

/*
 *  Shrink strtable allocation in-place.
 */

#if defined(DUK__STRTAB_RESIZE_CHECK)
DUK_LOCAL void duk__strtable_shrink_inplace(duk_heap *heap) {
	duk_uint32_t new_st_size;
	duk_uint32_t i;
	duk_hstring *h;
	duk_hstring *other;
	duk_hstring *root;
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *old_ptr;
	duk_uint16_t *old_ptr_high;
	duk_uint16_t *new_ptr;
#else
	duk_hstring **old_ptr;
	duk_hstring **old_ptr_high;
	duk_hstring **new_ptr;
#endif

	DUK_DD(DUK_DDPRINT("shrink in-place: %lu -> %lu", (unsigned long) heap->st_size, (unsigned long) heap->st_size / 2));

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(heap->st_resizing == 1);
	DUK_ASSERT(heap->st_size >= 2);
	DUK_ASSERT((heap->st_size & (heap->st_size - 1)) == 0);  /* 2^N */
	DUK_ASSERT(DUK__GET_STRTABLE(heap) != NULL);

	DUK_STATS_INC(heap, stats_strtab_resize_shrink);

	new_st_size = heap->st_size >> 1U;

	/* Combine two buckets into a single one.  When we shrink, one hash
	 * bit (highest) disappears.
	 */
	old_ptr = DUK__GET_STRTABLE(heap);
	old_ptr_high = old_ptr + new_st_size;
	for (i = 0; i < new_st_size; i++) {
		h = DUK__HEAPPTR_DEC16(heap, old_ptr[i]);
		other = DUK__HEAPPTR_DEC16(heap, old_ptr_high[i]);

		if (h == NULL) {
			/* First chain is empty, so use second one as is. */
			root = other;
		} else {
			/* Find end of first chain, and link in the second. */
			root = h;
			while (h->hdr.h_next != NULL) {
				h = h->hdr.h_next;
			}
			h->hdr.h_next = other;
		}

		old_ptr[i] = DUK__HEAPPTR_ENC16(heap, root);
	}

	heap->st_size = new_st_size;
	heap->st_mask = new_st_size - 1;

	/* The strtable is now consistent and we can realloc safely.  Even
	 * if side effects cause string interning or removal the strtable
	 * updates are safe.  Recursive resize has been prevented by caller.
	 * This is also why we don't need to use DUK_REALLOC_INDIRECT().
	 *
	 * We assume a realloc() to a smaller size is guaranteed to succeed.
	 * It would be relatively straightforward to handle the error by
	 * essentially performing a "grow" step to recover.
	 */

#if defined(DUK_USE_STRTAB_PTRCOMP)
	new_ptr = (duk_uint16_t *) DUK_REALLOC(heap, heap->strtable16, sizeof(duk_uint16_t) * new_st_size);
	DUK_ASSERT(new_ptr != NULL);
	heap->strtable16 = new_ptr;
#else
	new_ptr = (duk_hstring **) DUK_REALLOC(heap, heap->strtable, sizeof(duk_hstring *) * new_st_size);
	DUK_ASSERT(new_ptr != NULL);
	heap->strtable = new_ptr;
#endif

#if defined(DUK_USE_ASSERTIONS)
	duk__strtable_assert_checks(heap);
#endif
}
#endif  /* DUK__STRTAB_RESIZE_CHECK */

/*
 *  Grow/shrink check.
 */

#if defined(DUK__STRTAB_RESIZE_CHECK)
DUK_LOCAL DUK_COLD DUK_NOINLINE void duk__strtable_resize_check(duk_heap *heap) {
	duk_uint32_t load_factor;  /* fixed point */

	DUK_ASSERT(heap != NULL);
#if defined(DUK_USE_STRTAB_PTRCOMP)
	DUK_ASSERT(heap->strtable16 != NULL);
#else
	DUK_ASSERT(heap->strtable != NULL);
#endif

	DUK_STATS_INC(heap, stats_strtab_resize_check);

	/* Prevent recursive resizing. */
	if (DUK_UNLIKELY(heap->st_resizing != 0U)) {
		DUK_D(DUK_DPRINT("prevent recursive strtable resize"));
		return;
	}

	heap->st_resizing = 1;

	DUK_ASSERT(heap->st_size >= 16U);
	DUK_ASSERT((heap->st_size >> 4U) >= 1);
	load_factor = heap->st_count / (heap->st_size >> 4U);

	DUK_DD(DUK_DDPRINT("resize check string table: size=%lu, count=%lu, load_factor=%lu (fixed point .4; float %lf)",
	                   (unsigned long) heap->st_size, (unsigned long) heap->st_count,
	                   (unsigned long) load_factor,
	                   (double) heap->st_count / (double) heap->st_size));

	if (load_factor >= DUK_USE_STRTAB_GROW_LIMIT) {
		if (heap->st_size >= DUK_USE_STRTAB_MAXSIZE) {
			DUK_DD(DUK_DDPRINT("want to grow strtable (based on load factor) but already maximum size"));
		} else {
			DUK_D(DUK_DPRINT("grow string table: %lu -> %lu", (unsigned long) heap->st_size, (unsigned long) heap->st_size * 2));
#if defined(DUK_USE_DEBUG)
			duk_heap_strtable_dump(heap);
#endif
			duk__strtable_grow_inplace(heap);
		}
	} else if (load_factor <= DUK_USE_STRTAB_SHRINK_LIMIT) {
		if (heap->st_size <= DUK_USE_STRTAB_MINSIZE) {
			DUK_DD(DUK_DDPRINT("want to shrink strtable (based on load factor) but already minimum size"));
		} else {
			DUK_D(DUK_DPRINT("shrink string table: %lu -> %lu", (unsigned long) heap->st_size, (unsigned long) heap->st_size / 2));
#if defined(DUK_USE_DEBUG)
			duk_heap_strtable_dump(heap);
#endif
			duk__strtable_shrink_inplace(heap);
		}
	} else {
		DUK_DD(DUK_DDPRINT("no need for strtable resize"));
	}

	heap->st_resizing = 0;
}
#endif  /* DUK__STRTAB_RESIZE_CHECK */

/*
 *  Torture grow/shrink: unconditionally grow and shrink back.
 */

#if defined(DUK_USE_STRTAB_TORTURE) && defined(DUK__STRTAB_RESIZE_CHECK)
DUK_LOCAL void duk__strtable_resize_torture(duk_heap *heap) {
	duk_uint32_t old_st_size;

	DUK_ASSERT(heap != NULL);

	old_st_size = heap->st_size;
	if (old_st_size >= DUK_USE_STRTAB_MAXSIZE) {
		return;
	}

	heap->st_resizing = 1;
	duk__strtable_grow_inplace(heap);
	if (heap->st_size > old_st_size) {
		duk__strtable_shrink_inplace(heap);
	}
	heap->st_resizing = 0;
}
#endif  /* DUK_USE_STRTAB_TORTURE && DUK__STRTAB_RESIZE_CHECK */

/*
 *  Raw intern; string already checked not to be present.
 */

DUK_LOCAL duk_hstring *duk__strtable_do_intern(duk_heap *heap, const duk_uint8_t *str, duk_uint32_t blen, duk_uint32_t strhash) {
	duk_hstring *res;
	const duk_uint8_t *extdata;
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *slot;
#else
	duk_hstring **slot;
#endif

	DUK_DDD(DUK_DDDPRINT("do_intern: heap=%p, str=%p, blen=%lu, strhash=%lx, st_size=%lu, st_count=%lu, load=%lf",
	                     (void *) heap, (const void *) str, (unsigned long) blen, (unsigned long) strhash,
	                     (unsigned long) heap->st_size, (unsigned long) heap->st_count,
	                     (double) heap->st_count / (double) heap->st_size));

	DUK_ASSERT(heap != NULL);

	/* Prevent any side effects on the string table and the caller provided
	 * str/blen arguments while interning is in progress.  For example, if
	 * the caller provided str/blen from a dynamic buffer, a finalizer
	 * might resize or modify that dynamic buffer, invalidating the call
	 * arguments.
	 *
	 * While finalizers must be prevented, mark-and-sweep itself is fine.
	 * Recursive string table resize is prevented explicitly here.
	 */

	heap->pf_prevent_count++;
	DUK_ASSERT(heap->pf_prevent_count != 0);  /* Wrap. */

#if defined(DUK_USE_STRTAB_TORTURE) && defined(DUK__STRTAB_RESIZE_CHECK)
	duk__strtable_resize_torture(heap);
#endif

	/* String table grow/shrink check.  Because of chaining (and no
	 * accumulation issues as with hash probe chains and DELETED
	 * markers) there's never a mandatory need to resize right now.
	 * Check for the resize only periodically, based on st_count
	 * bit pattern.  Because string table removal doesn't do a shrink
	 * check, we do that also here.
	 *
	 * Do the resize and possible grow/shrink before the new duk_hstring
	 * has been allocated.  Otherwise we may trigger a GC when the result
	 * duk_hstring is not yet strongly referenced.
	 */

#if defined(DUK__STRTAB_RESIZE_CHECK)
	if (DUK_UNLIKELY((heap->st_count & DUK_USE_STRTAB_RESIZE_CHECK_MASK) == 0)) {
		duk__strtable_resize_check(heap);
	}
#endif

	/* External string check (low memory optimization). */

#if defined(DUK_USE_HSTRING_EXTDATA) && defined(DUK_USE_EXTSTR_INTERN_CHECK)
	extdata = (const duk_uint8_t *) DUK_USE_EXTSTR_INTERN_CHECK(heap->heap_udata, (void *) DUK_LOSE_CONST(str), (duk_size_t) blen);
#else
	extdata = (const duk_uint8_t *) NULL;
#endif

	/* Allocate and initialize string, not yet linked.  This may cause a
	 * GC which may cause other strings to be interned and inserted into
	 * the string table before we insert our string.  Finalizer execution
	 * is disabled intentionally to avoid a finalizer from e.g. resizing
	 * a buffer used as a data area for 'str'.
	 */

	res = duk__strtable_alloc_hstring(heap, str, blen, strhash, extdata);

	/* Allow side effects again: GC must be avoided until duk_hstring
	 * result (if successful) has been INCREF'd.
	 */
	DUK_ASSERT(heap->pf_prevent_count > 0);
	heap->pf_prevent_count--;

	/* Alloc error handling. */

	if (DUK_UNLIKELY(res == NULL)) {
#if defined(DUK_USE_HSTRING_EXTDATA) && defined(DUK_USE_EXTSTR_INTERN_CHECK)
		if (extdata != NULL) {
			DUK_USE_EXTSTR_FREE(heap->heap_udata, (const void *) extdata);
		}
#endif
		return NULL;
	}

	/* Insert into string table. */

#if defined(DUK_USE_STRTAB_PTRCOMP)
	slot = heap->strtable16 + (strhash & heap->st_mask);
#else
	slot = heap->strtable + (strhash & heap->st_mask);
#endif
	DUK_ASSERT(res->hdr.h_next == NULL);  /* This is the case now, but unnecessary zeroing/NULLing. */
	res->hdr.h_next = DUK__HEAPPTR_DEC16(heap, *slot);
	*slot = DUK__HEAPPTR_ENC16(heap, res);

	/* Update string count only for successful inserts. */

#if defined(DUK__STRTAB_RESIZE_CHECK)
	heap->st_count++;
#endif

	/* The duk_hstring is in the string table but is not yet strongly
	 * reachable.  Calling code MUST NOT make any allocations or other
	 * side effects before the duk_hstring has been INCREF'd and made
	 * reachable.
	 */

	return res;
}

/*
 *  Intern a string from str/blen, returning either an existing duk_hstring
 *  or adding a new one into the string table.  The input string does -not-
 *  need to be NUL terminated.
 *
 *  The input 'str' argument may point to a Duktape managed data area such as
 *  the data area of a dynamic buffer.  It's crucial to avoid any side effects
 *  that might affect the data area (e.g. resize the dynamic buffer, or write
 *  to the buffer) before the string is fully interned.
 */

#if defined(DUK_USE_ROM_STRINGS)
DUK_LOCAL duk_hstring *duk__strtab_romstring_lookup(duk_heap *heap, const duk_uint8_t *str, duk_size_t blen, duk_uint32_t strhash) {
	duk_size_t lookup_hash;
	duk_hstring *curr;

	DUK_ASSERT(heap != NULL);
	DUK_UNREF(heap);

	lookup_hash = (blen << 4);
	if (blen > 0) {
		lookup_hash += str[0];
	}
	lookup_hash &= 0xff;

	curr = (duk_hstring *) DUK_LOSE_CONST(duk_rom_strings_lookup[lookup_hash]);
	while (curr != NULL) {
		/* Unsafe memcmp() because for zero blen, str may be NULL. */
		if (strhash == DUK_HSTRING_GET_HASH(curr) &&
		    blen == DUK_HSTRING_GET_BYTELEN(curr) &&
		    duk_memcmp_unsafe((const void *) str, (const void *) DUK_HSTRING_GET_DATA(curr), blen) == 0) {
			DUK_DDD(DUK_DDDPRINT("intern check: rom string: %!O, computed hash 0x%08lx, rom hash 0x%08lx",
			                     curr, (unsigned long) strhash, (unsigned long) DUK_HSTRING_GET_HASH(curr)));
			return curr;
		}
		curr = curr->hdr.h_next;
	}

	return NULL;
}
#endif  /* DUK_USE_ROM_STRINGS */

DUK_INTERNAL duk_hstring *duk_heap_strtable_intern(duk_heap *heap, const duk_uint8_t *str, duk_uint32_t blen) {
	duk_uint32_t strhash;
	duk_hstring *h;

	DUK_DDD(DUK_DDDPRINT("intern check: heap=%p, str=%p, blen=%lu", (void *) heap, (const void *) str, (unsigned long) blen));

	/* Preliminaries. */

	/* XXX: maybe just require 'str != NULL' even for zero size? */
	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(blen == 0 || str != NULL);
	DUK_ASSERT(blen <= DUK_HSTRING_MAX_BYTELEN);  /* Caller is responsible for ensuring this. */
	strhash = duk_heap_hashstring(heap, str, (duk_size_t) blen);

	/* String table lookup. */

	DUK_ASSERT(DUK__GET_STRTABLE(heap) != NULL);
	DUK_ASSERT(heap->st_size > 0);
	DUK_ASSERT(heap->st_size == heap->st_mask + 1);
#if defined(DUK_USE_STRTAB_PTRCOMP)
	h = DUK__HEAPPTR_DEC16(heap, heap->strtable16[strhash & heap->st_mask]);
#else
	h = heap->strtable[strhash & heap->st_mask];
#endif
	while (h != NULL) {
		if (DUK_HSTRING_GET_HASH(h) == strhash &&
		    DUK_HSTRING_GET_BYTELEN(h) == blen &&
		    duk_memcmp_unsafe((const void *) str, (const void *) DUK_HSTRING_GET_DATA(h), (size_t) blen) == 0) {
			/* Found existing entry. */
			DUK_STATS_INC(heap, stats_strtab_intern_hit);
			return h;
		}
		h = h->hdr.h_next;
	}

	/* ROM table lookup.  Because this lookup is slower, do it only after
	 * RAM lookup.  This works because no ROM string is ever interned into
	 * the RAM string table.
	 */

#if defined(DUK_USE_ROM_STRINGS)
	h = duk__strtab_romstring_lookup(heap, str, blen, strhash);
	if (h != NULL) {
		DUK_STATS_INC(heap, stats_strtab_intern_hit);
		return h;
	}
#endif

	/* Not found in string table; insert. */

	DUK_STATS_INC(heap, stats_strtab_intern_miss);
	h = duk__strtable_do_intern(heap, str, blen, strhash);
	return h;  /* may be NULL */
}

/*
 *  Intern a string from u32.
 */

/* XXX: Could arrange some special handling because we know that the result
 * will have an arridx flag and an ASCII flag, won't need a clen check, etc.
 */

DUK_INTERNAL duk_hstring *duk_heap_strtable_intern_u32(duk_heap *heap, duk_uint32_t val) {
	duk_uint8_t buf[DUK__STRTAB_U32_MAX_STRLEN];
	duk_uint8_t *p;

	DUK_ASSERT(heap != NULL);

	/* This is smaller and faster than a %lu sprintf. */
	p = buf + sizeof(buf);
	do {
		p--;
		*p = duk_lc_digits[val % 10];
		val = val / 10;
	} while (val != 0);  /* For val == 0, emit exactly one '0'. */
	DUK_ASSERT(p >= buf);

	return duk_heap_strtable_intern(heap, (const duk_uint8_t *) p, (duk_uint32_t) ((buf + sizeof(buf)) - p));
}

/*
 *  Checked convenience variants.
 *
 *  XXX: Because the main use case is for the checked variants, make them the
 *  main functionality and provide a safe variant separately (it is only needed
 *  during heap init).  The problem with that is that longjmp state and error
 *  creation must already be possible to throw.
 */

DUK_INTERNAL duk_hstring *duk_heap_strtable_intern_checked(duk_hthread *thr, const duk_uint8_t *str, duk_uint32_t blen) {
	duk_hstring *res;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(blen == 0 || str != NULL);

	res = duk_heap_strtable_intern(thr->heap, str, blen);
	if (DUK_UNLIKELY(res == NULL)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}
	return res;
}

#if defined(DUK_USE_LITCACHE_SIZE)
DUK_LOCAL duk_uint_t duk__strtable_litcache_key(const duk_uint8_t *str, duk_uint32_t blen) {
	duk_uintptr_t key;

	DUK_ASSERT(DUK_USE_LITCACHE_SIZE > 0);
	DUK_ASSERT(DUK_IS_POWER_OF_TWO((duk_uint_t) DUK_USE_LITCACHE_SIZE));

	key = (duk_uintptr_t) blen ^ (duk_uintptr_t) str;
	key &= (duk_uintptr_t) (DUK_USE_LITCACHE_SIZE - 1);  /* Assumes size is power of 2. */
	/* Due to masking, cast is in 32-bit range. */
	DUK_ASSERT(key <= DUK_UINT_MAX);
	return (duk_uint_t) key;
}

DUK_INTERNAL duk_hstring *duk_heap_strtable_intern_literal_checked(duk_hthread *thr, const duk_uint8_t *str, duk_uint32_t blen) {
	duk_uint_t key;
	duk_litcache_entry *ent;
	duk_hstring *h;

	/* Fast path check: literal exists in literal cache. */
	key = duk__strtable_litcache_key(str, blen);
	ent = thr->heap->litcache + key;
	if (ent->addr == str) {
		DUK_DD(DUK_DDPRINT("intern check for cached, pinned literal: str=%p, blen=%ld -> duk_hstring %!O",
		                   (const void *) str, (long) blen, (duk_heaphdr *) ent->h));
		DUK_ASSERT(ent->h != NULL);
		DUK_ASSERT(DUK_HSTRING_HAS_PINNED_LITERAL(ent->h));
		DUK_STATS_INC(thr->heap, stats_strtab_litcache_hit);
		return ent->h;
	}

	/* Intern and update (overwrite) cache entry. */
	h = duk_heap_strtable_intern_checked(thr, str, blen);
	ent->addr = str;
	ent->h = h;
	DUK_STATS_INC(thr->heap, stats_strtab_litcache_miss);

	/* Pin the duk_hstring until the next mark-and-sweep.  This means
	 * litcache entries don't need to be invalidated until the next
	 * mark-and-sweep as their target duk_hstring is not freed before
	 * the mark-and-sweep happens.  The pin remains even if the literal
	 * cache entry is overwritten, and is still useful to avoid string
	 * table traffic.
	 */
	if (!DUK_HSTRING_HAS_PINNED_LITERAL(h)) {
		DUK_DD(DUK_DDPRINT("pin duk_hstring because it is a literal: %!O", (duk_heaphdr *) h));
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h));
		DUK_HSTRING_INCREF(thr, h);
		DUK_HSTRING_SET_PINNED_LITERAL(h);
		DUK_STATS_INC(thr->heap, stats_strtab_litcache_pin);
	}

	return h;
}
#endif  /* DUK_USE_LITCACHE_SIZE */

DUK_INTERNAL duk_hstring *duk_heap_strtable_intern_u32_checked(duk_hthread *thr, duk_uint32_t val) {
	duk_hstring *res;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

	res = duk_heap_strtable_intern_u32(thr->heap, val);
	if (DUK_UNLIKELY(res == NULL)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}
	return res;
}

/*
 *  Remove (unlink) a string from the string table.
 *
 *  Just unlinks the duk_hstring, leaving link pointers as garbage.
 *  Caller must free the string itself.
 */

#if defined(DUK_USE_REFERENCE_COUNTING)
/* Unlink without a 'prev' pointer. */
DUK_INTERNAL void duk_heap_strtable_unlink(duk_heap *heap, duk_hstring *h) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *slot;
#else
	duk_hstring **slot;
#endif
	duk_hstring *other;
	duk_hstring *prev;

	DUK_DDD(DUK_DDDPRINT("remove: heap=%p, h=%p, blen=%lu, strhash=%lx",
	                     (void *) heap, (void *) h,
	                     (unsigned long) (h != NULL ? DUK_HSTRING_GET_BYTELEN(h) : 0),
	                     (unsigned long) (h != NULL ? DUK_HSTRING_GET_HASH(h) : 0)));

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

#if defined(DUK__STRTAB_RESIZE_CHECK)
	DUK_ASSERT(heap->st_count > 0);
	heap->st_count--;
#endif

#if defined(DUK_USE_STRTAB_PTRCOMP)
	slot = heap->strtable16 + (DUK_HSTRING_GET_HASH(h) & heap->st_mask);
#else
	slot = heap->strtable + (DUK_HSTRING_GET_HASH(h) & heap->st_mask);
#endif
	other = DUK__HEAPPTR_DEC16(heap, *slot);
	DUK_ASSERT(other != NULL);  /* At least argument string is in the chain. */

	prev = NULL;
	while (other != h) {
		prev = other;
		other = other->hdr.h_next;
		DUK_ASSERT(other != NULL);  /* We'll eventually find 'h'. */
	}
	if (prev != NULL) {
		/* Middle of list. */
		prev->hdr.h_next = h->hdr.h_next;
	} else {
		/* Head of list. */
		*slot = DUK__HEAPPTR_ENC16(heap, h->hdr.h_next);
	}

	/* There's no resize check on a string free.  The next string
	 * intern will do one.
	 */
}
#endif  /* DUK_USE_REFERENCE_COUNTING */

/* Unlink with a 'prev' pointer. */
DUK_INTERNAL void duk_heap_strtable_unlink_prev(duk_heap *heap, duk_hstring *h, duk_hstring *prev) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *slot;
#else
	duk_hstring **slot;
#endif

	DUK_DDD(DUK_DDDPRINT("remove: heap=%p, prev=%p, h=%p, blen=%lu, strhash=%lx",
	                     (void *) heap, (void *) prev, (void *) h,
	                     (unsigned long) (h != NULL ? DUK_HSTRING_GET_BYTELEN(h) : 0),
	                     (unsigned long) (h != NULL ? DUK_HSTRING_GET_HASH(h) : 0)));

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(prev == NULL || prev->hdr.h_next == h);

#if defined(DUK__STRTAB_RESIZE_CHECK)
	DUK_ASSERT(heap->st_count > 0);
	heap->st_count--;
#endif

	if (prev != NULL) {
		/* Middle of list. */
		prev->hdr.h_next = h->hdr.h_next;
	} else {
		/* Head of list. */
#if defined(DUK_USE_STRTAB_PTRCOMP)
		slot = heap->strtable16 + (DUK_HSTRING_GET_HASH(h) & heap->st_mask);
#else
		slot = heap->strtable + (DUK_HSTRING_GET_HASH(h) & heap->st_mask);
#endif
		DUK_ASSERT(DUK__HEAPPTR_DEC16(heap, *slot) == h);
		*slot = DUK__HEAPPTR_ENC16(heap, h->hdr.h_next);
	}
}

/*
 *  Force string table resize check in mark-and-sweep.
 */

DUK_INTERNAL void duk_heap_strtable_force_resize(duk_heap *heap) {
	/* Does only one grow/shrink step if needed.  The heap->st_resizing
	 * flag protects against recursive resizing.
	 */

	DUK_ASSERT(heap != NULL);
	DUK_UNREF(heap);

#if defined(DUK__STRTAB_RESIZE_CHECK)
#if defined(DUK_USE_STRTAB_PTRCOMP)
	if (heap->strtable16 != NULL) {
#else
	if (heap->strtable != NULL) {
#endif
		duk__strtable_resize_check(heap);
	}
#endif
}

/*
 *  Free strings in the string table and the string table itself.
 */

DUK_INTERNAL void duk_heap_strtable_free(duk_heap *heap) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
	duk_uint16_t *strtable;
	duk_uint16_t *st;
#else
	duk_hstring **strtable;
	duk_hstring **st;
#endif
	duk_hstring *h;

	DUK_ASSERT(heap != NULL);

#if defined(DUK_USE_ASSERTIONS)
	duk__strtable_assert_checks(heap);
#endif

	/* Strtable can be NULL if heap init fails.  However, in that case
	 * heap->st_size is 0, so strtable == strtable_end and we skip the
	 * loop without a special check.
	 */
	strtable = DUK__GET_STRTABLE(heap);
	st = strtable + heap->st_size;
	DUK_ASSERT(strtable != NULL || heap->st_size == 0);

	while (strtable != st) {
		--st;
		h = DUK__HEAPPTR_DEC16(heap, *st);
		while (h) {
			duk_hstring *h_next;
			h_next = h->hdr.h_next;

			/* Strings may have inner refs (extdata) in some cases. */
			duk_free_hstring(heap, h);

			h = h_next;
		}
	}

	DUK_FREE(heap, strtable);
}

/* automatic undefs */
#undef DUK__GET_STRTABLE
#undef DUK__HEAPPTR_DEC16
#undef DUK__HEAPPTR_ENC16
#undef DUK__STRTAB_U32_MAX_STRLEN
/*
 *  duk_heaphdr assertion helpers
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ASSERTIONS)

#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
DUK_INTERNAL void duk_heaphdr_assert_links(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	if (h != NULL) {
		duk_heaphdr *h_prev, *h_next;
		h_prev = DUK_HEAPHDR_GET_PREV(heap, h);
		h_next = DUK_HEAPHDR_GET_NEXT(heap, h);
		DUK_ASSERT(h_prev == NULL || (DUK_HEAPHDR_GET_NEXT(heap, h_prev) == h));
		DUK_ASSERT(h_next == NULL || (DUK_HEAPHDR_GET_PREV(heap, h_next) == h));
	}
}
#else
DUK_INTERNAL void duk_heaphdr_assert_links(duk_heap *heap, duk_heaphdr *h) {
	DUK_UNREF(heap);
	DUK_UNREF(h);
}
#endif

DUK_INTERNAL void duk_heaphdr_assert_valid(duk_heaphdr *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
}

/* Assert validity of a heaphdr, including all subclasses. */
DUK_INTERNAL void duk_heaphdr_assert_valid_subclassed(duk_heaphdr *h) {
	switch (DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h_obj = (duk_hobject *) h;
		DUK_HOBJECT_ASSERT_VALID(h_obj);
		if (DUK_HOBJECT_IS_COMPFUNC(h_obj)) {
			DUK_HCOMPFUNC_ASSERT_VALID((duk_hcompfunc *) h_obj);
		} else if (DUK_HOBJECT_IS_NATFUNC(h_obj)) {
			DUK_HNATFUNC_ASSERT_VALID((duk_hnatfunc *) h_obj);
		} else if (DUK_HOBJECT_IS_DECENV(h_obj)) {
			DUK_HDECENV_ASSERT_VALID((duk_hdecenv *) h_obj);
		} else if (DUK_HOBJECT_IS_OBJENV(h_obj)) {
			DUK_HOBJENV_ASSERT_VALID((duk_hobjenv *) h_obj);
		} else if (DUK_HOBJECT_IS_BUFOBJ(h_obj)) {
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
			DUK_HBUFOBJ_ASSERT_VALID((duk_hbufobj *) h_obj);
#endif
		} else if (DUK_HOBJECT_IS_BOUNDFUNC(h_obj)) {
			DUK_HBOUNDFUNC_ASSERT_VALID((duk_hboundfunc *) h_obj);
		} else if (DUK_HOBJECT_IS_PROXY(h_obj)) {
			DUK_HPROXY_ASSERT_VALID((duk_hproxy *) h_obj);
		} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
			DUK_HTHREAD_ASSERT_VALID((duk_hthread *) h_obj);
		} else {
			/* Just a plain object. */
			;
		}
		break;
	}
	case DUK_HTYPE_STRING: {
		duk_hstring *h_str = (duk_hstring *) h;
		DUK_HSTRING_ASSERT_VALID(h_str);
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h_buf = (duk_hbuffer *) h;
		DUK_HBUFFER_ASSERT_VALID(h_buf);
		break;
	}
	default: {
		DUK_ASSERT(0);
	}
	}
}

#endif  /* DUK_USE_ASSERTIONS */
/*
 *  Hobject allocation.
 *
 *  Provides primitive allocation functions for all object types (plain object,
 *  compiled function, native function, thread).  The object return is not yet
 *  in "heap allocated" list and has a refcount of zero, so caller must careful.
 */

/* XXX: In most cases there's no need for plain allocation without pushing
 * to the value stack.  Maybe rework contract?
 */

/* #include duk_internal.h -> already included */

/*
 *  Helpers.
 */

DUK_LOCAL void duk__init_object_parts(duk_heap *heap, duk_uint_t hobject_flags, duk_hobject *obj) {
	DUK_ASSERT(obj != NULL);
	/* Zeroed by caller. */

	obj->hdr.h_flags = hobject_flags | DUK_HTYPE_OBJECT;
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(&obj->hdr) == DUK_HTYPE_OBJECT);  /* Assume zero shift. */

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	DUK_HOBJECT_SET_PROTOTYPE(heap, obj, NULL);
	DUK_HOBJECT_SET_PROPS(heap, obj, NULL);
#endif
#if defined(DUK_USE_HEAPPTR16)
	/* Zero encoded pointer is required to match NULL. */
	DUK_HEAPHDR_SET_NEXT(heap, &obj->hdr, NULL);
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
	DUK_HEAPHDR_SET_PREV(heap, &obj->hdr, NULL);
#endif
#endif
	DUK_HEAPHDR_ASSERT_LINKS(heap, &obj->hdr);
	DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, &obj->hdr);

	/* obj->props is intentionally left as NULL, and duk_hobject_props.c must deal
	 * with this properly.  This is intentional: empty objects consume a minimum
	 * amount of memory.  Further, an initial allocation might fail and cause
	 * 'obj' to "leak" (require a mark-and-sweep) since it is not reachable yet.
	 */
}

DUK_LOCAL void *duk__hobject_alloc_init(duk_hthread *thr, duk_uint_t hobject_flags, duk_size_t size) {
	void *res;

	res = (void *) DUK_ALLOC_CHECKED_ZEROED(thr, size);
	DUK_ASSERT(res != NULL);
	duk__init_object_parts(thr->heap, hobject_flags, (duk_hobject *) res);
	return res;
}

/*
 *  Allocate an duk_hobject.
 *
 *  The allocated object has no allocation for properties; the caller may
 *  want to force a resize if a desired size is known.
 *
 *  The allocated object has zero reference count and is not reachable.
 *  The caller MUST make the object reachable and increase its reference
 *  count before invoking any operation that might require memory allocation.
 */

DUK_INTERNAL duk_hobject *duk_hobject_alloc_unchecked(duk_heap *heap, duk_uint_t hobject_flags) {
	duk_hobject *res;

	DUK_ASSERT(heap != NULL);

	/* different memory layout, alloc size, and init */
	DUK_ASSERT((hobject_flags & DUK_HOBJECT_FLAG_COMPFUNC) == 0);
	DUK_ASSERT((hobject_flags & DUK_HOBJECT_FLAG_NATFUNC) == 0);
	DUK_ASSERT((hobject_flags & DUK_HOBJECT_FLAG_BOUNDFUNC) == 0);

	res = (duk_hobject *) DUK_ALLOC_ZEROED(heap, sizeof(duk_hobject));
	if (DUK_UNLIKELY(res == NULL)) {
		return NULL;
	}
	DUK_ASSERT(!DUK_HOBJECT_IS_THREAD(res));

	duk__init_object_parts(heap, hobject_flags, res);

	DUK_ASSERT(!DUK_HOBJECT_IS_THREAD(res));
	return res;
}

DUK_INTERNAL duk_hobject *duk_hobject_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hobject *res;

	res = (duk_hobject *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hobject));
	return res;
}

DUK_INTERNAL duk_hcompfunc *duk_hcompfunc_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hcompfunc *res;

	res = (duk_hcompfunc *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hcompfunc));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
#if defined(DUK_USE_HEAPPTR16)
	/* NULL pointer is required to encode to zero, so memset is enough. */
#else
	res->data = NULL;
	res->funcs = NULL;
	res->bytecode = NULL;
#endif
	res->lex_env = NULL;
	res->var_env = NULL;
#endif

	return res;
}

DUK_INTERNAL duk_hnatfunc *duk_hnatfunc_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hnatfunc *res;

	res = (duk_hnatfunc *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hnatfunc));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->func = NULL;
#endif

	return res;
}

DUK_INTERNAL duk_hboundfunc *duk_hboundfunc_alloc(duk_heap *heap, duk_uint_t hobject_flags) {
	duk_hboundfunc *res;

	res = (duk_hboundfunc *) DUK_ALLOC(heap, sizeof(duk_hboundfunc));
	if (!res) {
		return NULL;
	}
	duk_memzero(res, sizeof(duk_hboundfunc));

	duk__init_object_parts(heap, hobject_flags, &res->obj);

	DUK_TVAL_SET_UNDEFINED(&res->target);
	DUK_TVAL_SET_UNDEFINED(&res->this_binding);

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->args = NULL;
#endif

	return res;
}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL duk_hbufobj *duk_hbufobj_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hbufobj *res;

	res = (duk_hbufobj *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hbufobj));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->buf = NULL;
	res->buf_prop = NULL;
#endif

	DUK_HBUFOBJ_ASSERT_VALID(res);
	return res;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/* Allocate a new thread.
 *
 * Leaves the built-ins array uninitialized.  The caller must either
 * initialize a new global context or share existing built-ins from
 * another thread.
 */
DUK_INTERNAL duk_hthread *duk_hthread_alloc_unchecked(duk_heap *heap, duk_uint_t hobject_flags) {
	duk_hthread *res;

	res = (duk_hthread *) DUK_ALLOC(heap, sizeof(duk_hthread));
	if (DUK_UNLIKELY(res == NULL)) {
		return NULL;
	}
	duk_memzero(res, sizeof(duk_hthread));

	duk__init_object_parts(heap, hobject_flags, &res->obj);

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->ptr_curr_pc = NULL;
	res->heap = NULL;
	res->valstack = NULL;
	res->valstack_end = NULL;
	res->valstack_alloc_end = NULL;
	res->valstack_bottom = NULL;
	res->valstack_top = NULL;
	res->callstack_curr = NULL;
	res->resumer = NULL;
	res->compile_ctx = NULL,
#if defined(DUK_USE_HEAPPTR16)
	res->strs16 = NULL;
#else
	res->strs = NULL;
#endif
	{
		duk_small_uint_t i;
		for (i = 0; i < DUK_NUM_BUILTINS; i++) {
			res->builtins[i] = NULL;
		}
	}
#endif
	/* When nothing is running, API calls are in non-strict mode. */
	DUK_ASSERT(res->strict == 0);

	res->heap = heap;

	/* XXX: Any reason not to merge duk_hthread_alloc.c here? */
	return res;
}

DUK_INTERNAL duk_hthread *duk_hthread_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hthread *res;

	res = duk_hthread_alloc_unchecked(thr->heap, hobject_flags);
	if (res == NULL) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return NULL;);
	}
	return res;
}

DUK_INTERNAL duk_harray *duk_harray_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_harray *res;

	res = (duk_harray *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_harray));

	DUK_ASSERT(res->length == 0);

	return res;
}

DUK_INTERNAL duk_hdecenv *duk_hdecenv_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hdecenv *res;

	res = (duk_hdecenv *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hdecenv));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->thread = NULL;
	res->varmap = NULL;
#endif

	DUK_ASSERT(res->thread == NULL);
	DUK_ASSERT(res->varmap == NULL);
	DUK_ASSERT(res->regbase_byteoff == 0);

	return res;
}

DUK_INTERNAL duk_hobjenv *duk_hobjenv_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hobjenv *res;

	res = (duk_hobjenv *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hobjenv));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	res->target = NULL;
#endif

	DUK_ASSERT(res->target == NULL);

	return res;
}

DUK_INTERNAL duk_hproxy *duk_hproxy_alloc(duk_hthread *thr, duk_uint_t hobject_flags) {
	duk_hproxy *res;

	res = (duk_hproxy *) duk__hobject_alloc_init(thr, hobject_flags, sizeof(duk_hproxy));

	/* Leave ->target and ->handler uninitialized, as caller will always
	 * explicitly initialize them before any side effects are possible.
	 */

	return res;
}
/*
 *  duk_hobject and subclass assertion helpers
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ASSERTIONS)

DUK_INTERNAL void duk_hobject_assert_valid(duk_hobject *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(!DUK_HOBJECT_IS_CALLABLE(h) ||
	           DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_FUNCTION);
	DUK_ASSERT(!DUK_HOBJECT_IS_BUFOBJ(h) ||
	           (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_ARRAYBUFFER ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_DATAVIEW ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_INT8ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_UINT8ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_UINT8CLAMPEDARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_INT16ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_UINT16ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_INT32ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_UINT32ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_FLOAT32ARRAY ||
	            DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_FLOAT64ARRAY));
	/* Object is an Array <=> object has exotic array behavior */
	DUK_ASSERT((DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_ARRAY && DUK_HOBJECT_HAS_EXOTIC_ARRAY(h)) ||
	           (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_ARRAY && !DUK_HOBJECT_HAS_EXOTIC_ARRAY(h)));
}

DUK_INTERNAL void duk_harray_assert_valid(duk_harray *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_ARRAY((duk_hobject *) h));
	DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY((duk_hobject *) h));
}

DUK_INTERNAL void duk_hboundfunc_assert_valid(duk_hboundfunc *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_BOUNDFUNC((duk_hobject *) h));
	DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(&h->target) ||
	           (DUK_TVAL_IS_OBJECT(&h->target) &&
	            DUK_HOBJECT_IS_CALLABLE(DUK_TVAL_GET_OBJECT(&h->target))));
	DUK_ASSERT(!DUK_TVAL_IS_UNUSED(&h->this_binding));
	DUK_ASSERT(h->nargs == 0 || h->args != NULL);
}

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_INTERNAL void duk_hbufobj_assert_valid(duk_hbufobj *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(h->shift <= 3);
	DUK_ASSERT(h->elem_type <= DUK_HBUFOBJ_ELEM_MAX);
	DUK_ASSERT((h->shift == 0 && h->elem_type == DUK_HBUFOBJ_ELEM_UINT8) ||
	           (h->shift == 0 && h->elem_type == DUK_HBUFOBJ_ELEM_UINT8CLAMPED) ||
	           (h->shift == 0 && h->elem_type == DUK_HBUFOBJ_ELEM_INT8) ||
	           (h->shift == 1 && h->elem_type == DUK_HBUFOBJ_ELEM_UINT16) ||
	           (h->shift == 1 && h->elem_type == DUK_HBUFOBJ_ELEM_INT16) ||
	           (h->shift == 2 && h->elem_type == DUK_HBUFOBJ_ELEM_UINT32) ||
	           (h->shift == 2 && h->elem_type == DUK_HBUFOBJ_ELEM_INT32) ||
	           (h->shift == 2 && h->elem_type == DUK_HBUFOBJ_ELEM_FLOAT32) ||
	           (h->shift == 3 && h->elem_type == DUK_HBUFOBJ_ELEM_FLOAT64));
	DUK_ASSERT(h->is_typedarray == 0 || h->is_typedarray == 1);
	DUK_ASSERT(DUK_HOBJECT_IS_BUFOBJ((duk_hobject *) h));
	if (h->buf == NULL) {
		DUK_ASSERT(h->offset == 0);
		DUK_ASSERT(h->length == 0);
	} else {
		/* No assertions for offset or length; in particular,
		 * it's OK for length to be longer than underlying
		 * buffer.  Just ensure they don't wrap when added.
		 */
		DUK_ASSERT(h->offset + h->length >= h->offset);
	}
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

DUK_INTERNAL void duk_hcompfunc_assert_valid(duk_hcompfunc *h) {
	DUK_ASSERT(h != NULL);
}

DUK_INTERNAL void duk_hnatfunc_assert_valid(duk_hnatfunc *h) {
	DUK_ASSERT(h != NULL);
}

DUK_INTERNAL void duk_hdecenv_assert_valid(duk_hdecenv *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_DECENV((duk_hobject *) h));
	DUK_ASSERT(h->thread == NULL || h->varmap != NULL);
}

DUK_INTERNAL void duk_hobjenv_assert_valid(duk_hobjenv *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_OBJENV((duk_hobject *) h));
	DUK_ASSERT(h->target != NULL);
	DUK_ASSERT(h->has_this == 0 || h->has_this == 1);
}

DUK_INTERNAL void duk_hproxy_assert_valid(duk_hproxy *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(h->target != NULL);
	DUK_ASSERT(h->handler != NULL);
	DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ((duk_hobject *) h));
}

DUK_INTERNAL void duk_hthread_assert_valid(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) thr) == DUK_HTYPE_OBJECT);
	DUK_ASSERT(DUK_HOBJECT_IS_THREAD((duk_hobject *) thr));
	DUK_ASSERT(thr->unused1 == 0);
	DUK_ASSERT(thr->unused2 == 0);
}

DUK_INTERNAL void duk_ctx_assert_valid(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);
	DUK_HTHREAD_ASSERT_VALID(thr);
	DUK_ASSERT(thr->valstack != NULL);
	DUK_ASSERT(thr->valstack_bottom != NULL);
	DUK_ASSERT(thr->valstack_top != NULL);
	DUK_ASSERT(thr->valstack_end != NULL);
	DUK_ASSERT(thr->valstack_alloc_end != NULL);
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack);
	DUK_ASSERT(thr->valstack_end >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
	DUK_ASSERT(thr->valstack_alloc_end >= thr->valstack_end);
}

#endif  /* DUK_USE_ASSERTIONS */
/*
 *  Object enumeration support.
 *
 *  Creates an internal enumeration state object to be used e.g. with for-in
 *  enumeration.  The state object contains a snapshot of target object keys
 *  and internal control state for enumeration.  Enumerator flags allow caller
 *  to e.g. request internal/non-enumerable properties, and to enumerate only
 *  "own" properties.
 *
 *  Also creates the result value for e.g. Object.keys() based on the same
 *  internal structure.
 *
 *  This snapshot-based enumeration approach is used to simplify enumeration:
 *  non-snapshot-based approaches are difficult to reconcile with mutating
 *  the enumeration target, running multiple long-lived enumerators at the
 *  same time, garbage collection details, etc.  The downside is that the
 *  enumerator object is memory inefficient especially for iterating arrays.
 */

/* #include duk_internal.h -> already included */

/* XXX: identify enumeration target with an object index (not top of stack) */

/* First enumerated key index in enumerator object, must match exactly the
 * number of control properties inserted to the enumerator.
 */
#define DUK__ENUM_START_INDEX  2

/* Current implementation suffices for ES2015 for now because there's no symbol
 * sorting, so commented out for now.
 */

/*
 *  Helper to sort enumeration keys using a callback for pairwise duk_hstring
 *  comparisons.  The keys are in the enumeration object entry part, starting
 *  from DUK__ENUM_START_INDEX, and the entry part is dense.  Entry part values
 *  are all "true", e.g. "1" -> true, "3" -> true, "foo" -> true, "2" -> true,
 *  so it suffices to just switch keys without switching values.
 *
 *  ES2015 [[OwnPropertyKeys]] enumeration order for ordinary objects:
 *  (1) array indices in ascending order,
 *  (2) non-array-index keys in insertion order, and
 *  (3) symbols in insertion order.
 *  http://www.ecma-international.org/ecma-262/6.0/#sec-ordinary-object-internal-methods-and-internal-slots-ownpropertykeys.
 *
 *  This rule is applied to "own properties" at each inheritance level;
 *  non-duplicate parent keys always follow child keys.  For example,
 *  an inherited array index will enumerate -after- a symbol in the
 *  child.
 *
 *  Insertion sort is used because (1) it's simple and compact, (2) works
 *  in-place, (3) minimizes operations if data is already nearly sorted,
 *  (4) doesn't reorder elements considered equal.
 *  http://en.wikipedia.org/wiki/Insertion_sort
 */

/* Sort key, must hold array indices, "not array index" marker, and one more
 * higher value for symbols.
 */
#if !defined(DUK_USE_SYMBOL_BUILTIN)
typedef duk_uint32_t duk__sort_key_t;
#elif defined(DUK_USE_64BIT_OPS)
typedef duk_uint64_t duk__sort_key_t;
#else
typedef duk_double_t duk__sort_key_t;
#endif

/* Get sort key for a duk_hstring. */
DUK_LOCAL duk__sort_key_t duk__hstring_sort_key(duk_hstring *x) {
	duk__sort_key_t val;

	/* For array indices [0,0xfffffffe] use the array index as is.
	 * For strings, use 0xffffffff, the marker 'arridx' already in
	 * duk_hstring.  For symbols, any value above 0xffffffff works,
	 * as long as it is the same for all symbols; currently just add
	 * the masked flag field into the arridx temporary.
	 */
	DUK_ASSERT(x != NULL);
	DUK_ASSERT(!DUK_HSTRING_HAS_SYMBOL(x) || DUK_HSTRING_GET_ARRIDX_FAST(x) == DUK_HSTRING_NO_ARRAY_INDEX);

	val = (duk__sort_key_t) DUK_HSTRING_GET_ARRIDX_FAST(x);

#if defined(DUK_USE_SYMBOL_BUILTIN)
	val = val + (duk__sort_key_t) (DUK_HEAPHDR_GET_FLAGS_RAW((duk_heaphdr *) x) & DUK_HSTRING_FLAG_SYMBOL);
#endif

	return (duk__sort_key_t) val;
}

/* Insert element 'b' after element 'a'? */
DUK_LOCAL duk_bool_t duk__sort_compare_es6(duk_hstring *a, duk_hstring *b, duk__sort_key_t val_b) {
	duk__sort_key_t val_a;

	DUK_ASSERT(a != NULL);
	DUK_ASSERT(b != NULL);
	DUK_UNREF(b);  /* Not actually needed now, val_b suffices. */

	val_a = duk__hstring_sort_key(a);

	if (val_a > val_b) {
		return 0;
	} else {
		return 1;
	}
}

DUK_LOCAL void duk__sort_enum_keys_es6(duk_hthread *thr, duk_hobject *h_obj, duk_int_fast32_t idx_start, duk_int_fast32_t idx_end) {
	duk_hstring **keys;
	duk_int_fast32_t idx;

	DUK_ASSERT(h_obj != NULL);
	DUK_ASSERT(idx_start >= DUK__ENUM_START_INDEX);
	DUK_ASSERT(idx_end >= idx_start);
	DUK_UNREF(thr);

	if (idx_end <= idx_start + 1) {
		return;  /* Zero or one element(s). */
	}

	keys = DUK_HOBJECT_E_GET_KEY_BASE(thr->heap, h_obj);

	for (idx = idx_start + 1; idx < idx_end; idx++) {
		duk_hstring *h_curr;
		duk_int_fast32_t idx_insert;
		duk__sort_key_t val_curr;

		h_curr = keys[idx];
		DUK_ASSERT(h_curr != NULL);

		/* Scan backwards for insertion place.  This works very well
		 * when the elements are nearly in order which is the common
		 * (and optimized for) case.
		 */

		val_curr = duk__hstring_sort_key(h_curr);  /* Remains same during scanning. */
		for (idx_insert = idx - 1; idx_insert >= idx_start; idx_insert--) {
			duk_hstring *h_insert;
			h_insert = keys[idx_insert];
			DUK_ASSERT(h_insert != NULL);

			if (duk__sort_compare_es6(h_insert, h_curr, val_curr)) {
				break;
			}
		}
		/* If we're out of indices, idx_insert == idx_start - 1 and idx_insert++
		 * brings us back to idx_start.
		 */
		idx_insert++;
		DUK_ASSERT(idx_insert >= 0 && idx_insert <= idx);

		/*        .-- p_insert   .-- p_curr
		 *        v              v
		 *  | ... | insert | ... | curr
		 */

		/* This could also done when the keys are in order, i.e.
		 * idx_insert == idx.  The result would be an unnecessary
		 * memmove() but we use an explicit check because the keys
		 * are very often in order already.
		 */
		if (idx != idx_insert) {
			duk_memmove((void *) (keys + idx_insert + 1),
			            (const void *) (keys + idx_insert),
			            ((size_t) (idx - idx_insert) * sizeof(duk_hstring *)));
			keys[idx_insert] = h_curr;
		}
	}
}

/*
 *  Create an internal enumerator object E, which has its keys ordered
 *  to match desired enumeration ordering.  Also initialize internal control
 *  properties for enumeration.
 *
 *  Note: if an array was used to hold enumeration keys instead, an array
 *  scan would be needed to eliminate duplicates found in the prototype chain.
 */

DUK_LOCAL void duk__add_enum_key(duk_hthread *thr, duk_hstring *k) {
	/* 'k' may be unreachable on entry so must push without any
	 * potential for GC.
	 */
	duk_push_hstring(thr, k);
	duk_push_true(thr);
	duk_put_prop(thr, -3);
}

DUK_LOCAL void duk__add_enum_key_stridx(duk_hthread *thr, duk_small_uint_t stridx) {
	duk__add_enum_key(thr, DUK_HTHREAD_GET_STRING(thr, stridx));
}

DUK_INTERNAL void duk_hobject_enumerator_create(duk_hthread *thr, duk_small_uint_t enum_flags) {
	duk_hobject *enum_target;
	duk_hobject *curr;
	duk_hobject *res;
#if defined(DUK_USE_ES6_PROXY)
	duk_hobject *h_proxy_target;
	duk_hobject *h_proxy_handler;
	duk_hobject *h_trap_result;
#endif
	duk_uint_fast32_t i, len;  /* used for array, stack, and entry indices */
	duk_uint_fast32_t sort_start_index;

	DUK_ASSERT(thr != NULL);

	enum_target = duk_require_hobject(thr, -1);
	DUK_ASSERT(enum_target != NULL);

	duk_push_bare_object(thr);
	res = duk_known_hobject(thr, -1);

	/* [enum_target res] */

	/* Target must be stored so that we can recheck whether or not
	 * keys still exist when we enumerate.  This is not done if the
	 * enumeration result comes from a proxy trap as there is no
	 * real object to check against.
	 */
	duk_push_hobject(thr, enum_target);
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_INT_TARGET);  /* Target is bare, plain put OK. */

	/* Initialize index so that we skip internal control keys. */
	duk_push_int(thr, DUK__ENUM_START_INDEX);
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_INT_NEXT);  /* Target is bare, plain put OK. */

	/*
	 *  Proxy object handling
	 */

#if defined(DUK_USE_ES6_PROXY)
	if (DUK_LIKELY((enum_flags & DUK_ENUM_NO_PROXY_BEHAVIOR) != 0)) {
		goto skip_proxy;
	}
	if (DUK_LIKELY(!duk_hobject_proxy_check(enum_target,
	                                        &h_proxy_target,
	                                        &h_proxy_handler))) {
		goto skip_proxy;
	}

	/* XXX: share code with Object.keys() Proxy handling */

	/* In ES2015 for-in invoked the "enumerate" trap; in ES2016 "enumerate"
	 * has been obsoleted and "ownKeys" is used instead.
	 */
	DUK_DDD(DUK_DDDPRINT("proxy enumeration"));
	duk_push_hobject(thr, h_proxy_handler);
	if (!duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_OWN_KEYS)) {
		/* No need to replace the 'enum_target' value in stack, only the
		 * enum_target reference.  This also ensures that the original
		 * enum target is reachable, which keeps the proxy and the proxy
		 * target reachable.  We do need to replace the internal _Target.
		 */
		DUK_DDD(DUK_DDDPRINT("no ownKeys trap, enumerate proxy target instead"));
		DUK_DDD(DUK_DDDPRINT("h_proxy_target=%!O", (duk_heaphdr *) h_proxy_target));
		enum_target = h_proxy_target;

		duk_push_hobject(thr, enum_target);  /* -> [ ... enum_target res handler undefined target ] */
		duk_put_prop_stridx_short(thr, -4, DUK_STRIDX_INT_TARGET);  /* Target is bare, plain put OK. */

		duk_pop_2(thr);  /* -> [ ... enum_target res ] */
		goto skip_proxy;
	}

	/* [ ... enum_target res handler trap ] */
	duk_insert(thr, -2);
	duk_push_hobject(thr, h_proxy_target);    /* -> [ ... enum_target res trap handler target ] */
	duk_call_method(thr, 1 /*nargs*/);        /* -> [ ... enum_target res trap_result ] */
	h_trap_result = duk_require_hobject(thr, -1);
	DUK_UNREF(h_trap_result);

	duk_proxy_ownkeys_postprocess(thr, h_proxy_target, enum_flags);
	/* -> [ ... enum_target res trap_result keys_array ] */

	/* Copy cleaned up trap result keys into the enumerator object. */
	/* XXX: result is a dense array; could make use of that. */
	DUK_ASSERT(duk_is_array(thr, -1));
	len = (duk_uint_fast32_t) duk_get_length(thr, -1);
	for (i = 0; i < len; i++) {
		(void) duk_get_prop_index(thr, -1, (duk_uarridx_t) i);
		DUK_ASSERT(duk_is_string(thr, -1));  /* postprocess cleaned up */
		/* [ ... enum_target res trap_result keys_array val ] */
		duk_push_true(thr);
		/* [ ... enum_target res trap_result keys_array val true ] */
		duk_put_prop(thr, -5);
	}
	/* [ ... enum_target res trap_result keys_array ] */
	duk_pop_2(thr);
	duk_remove_m2(thr);

	/* [ ... res ] */

	/* The internal _Target property is kept pointing to the original
	 * enumeration target (the proxy object), so that the enumerator
	 * 'next' operation can read property values if so requested.  The
	 * fact that the _Target is a proxy disables key existence check
	 * during enumeration.
	 */
	DUK_DDD(DUK_DDDPRINT("proxy enumeration, final res: %!O", (duk_heaphdr *) res));
	goto compact_and_return;

 skip_proxy:
#endif  /* DUK_USE_ES6_PROXY */

	curr = enum_target;
	sort_start_index = DUK__ENUM_START_INDEX;
	DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(res) == DUK__ENUM_START_INDEX);
	while (curr) {
		duk_uint_fast32_t sort_end_index;
#if !defined(DUK_USE_PREFER_SIZE)
		duk_bool_t need_sort = 0;
#endif
		duk_bool_t cond;

		/* Enumeration proceeds by inheritance level.  Virtual
		 * properties need to be handled specially, followed by
		 * array part, and finally entry part.
		 *
		 * If there are array index keys in the entry part or any
		 * other risk of the ES2015 [[OwnPropertyKeys]] order being
		 * violated, need_sort is set and an explicit ES2015 sort is
		 * done for the inheritance level.
		 */

		/* XXX: inheriting from proxy */

		/*
		 *  Virtual properties.
		 *
		 *  String and buffer indices are virtual and always enumerable,
		 *  'length' is virtual and non-enumerable.  Array and arguments
		 *  object props have special behavior but are concrete.
		 *
		 *  String and buffer objects don't have an array part so as long
		 *  as virtual array index keys are enumerated first, we don't
		 *  need to set need_sort.
		 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		cond = DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(curr) || DUK_HOBJECT_IS_BUFOBJ(curr);
#else
		cond = DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(curr);
#endif
		cond = cond && !(enum_flags & DUK_ENUM_EXCLUDE_STRINGS);
		if (cond) {
			duk_bool_t have_length = 1;

			/* String and buffer enumeration behavior is identical now,
			 * so use shared handler.
			 */
			if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(curr)) {
				duk_hstring *h_val;
				h_val = duk_hobject_get_internal_value_string(thr->heap, curr);
				DUK_ASSERT(h_val != NULL);  /* string objects must not created without internal value */
				len = (duk_uint_fast32_t) DUK_HSTRING_GET_CHARLEN(h_val);
			}
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
			else {
				duk_hbufobj *h_bufobj;
				DUK_ASSERT(DUK_HOBJECT_IS_BUFOBJ(curr));
				h_bufobj = (duk_hbufobj *) curr;

				if (h_bufobj == NULL || !h_bufobj->is_typedarray) {
					/* Zero length seems like a good behavior for neutered buffers.
					 * ArrayBuffer (non-view) and DataView don't have index properties
					 * or .length property.
					 */
					len = 0;
					have_length = 0;
				} else {
					/* There's intentionally no check for
					 * current underlying buffer length.
					 */
					len = (duk_uint_fast32_t) (h_bufobj->length >> h_bufobj->shift);
				}
			}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

			for (i = 0; i < len; i++) {
				duk_hstring *k;

				/* This is a bit fragile: the string is not
				 * reachable until it is pushed by the helper.
				 */
				k = duk_heap_strtable_intern_u32_checked(thr, (duk_uint32_t) i);
				DUK_ASSERT(k);

				duk__add_enum_key(thr, k);

				/* [enum_target res] */
			}

			/* 'length' and other virtual properties are not
			 * enumerable, but are included if non-enumerable
			 * properties are requested.
			 */

			if (have_length && (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE)) {
				duk__add_enum_key_stridx(thr, DUK_STRIDX_LENGTH);
			}
		}

		/*
		 *  Array part
		 */

		cond = !(enum_flags & DUK_ENUM_EXCLUDE_STRINGS);
		if (cond) {
			for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(curr); i++) {
				duk_hstring *k;
				duk_tval *tv;

				tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, curr, i);
				if (DUK_TVAL_IS_UNUSED(tv)) {
					continue;
				}
				k = duk_heap_strtable_intern_u32_checked(thr, (duk_uint32_t) i);  /* Fragile reachability. */
				DUK_ASSERT(k);

				duk__add_enum_key(thr, k);

				/* [enum_target res] */
			}

			if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(curr)) {
				/* Array .length comes after numeric indices. */
				if (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) {
					duk__add_enum_key_stridx(thr, DUK_STRIDX_LENGTH);
				}
			}
		}

		/*
		 *  Entries part
		 */

		for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(curr); i++) {
			duk_hstring *k;

			k = DUK_HOBJECT_E_GET_KEY(thr->heap, curr, i);
			if (!k) {
				continue;
			}
			if (!(enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) &&
			    !DUK_HOBJECT_E_SLOT_IS_ENUMERABLE(thr->heap, curr, i)) {
				continue;
			}
			if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(k))) {
				if (!(enum_flags & DUK_ENUM_INCLUDE_HIDDEN) &&
				    DUK_HSTRING_HAS_HIDDEN(k)) {
					continue;
				}
				if (!(enum_flags & DUK_ENUM_INCLUDE_SYMBOLS)) {
					continue;
				}
#if !defined(DUK_USE_PREFER_SIZE)
				need_sort = 1;
#endif
			} else {
				DUK_ASSERT(!DUK_HSTRING_HAS_HIDDEN(k));  /* would also have symbol flag */
				if (enum_flags & DUK_ENUM_EXCLUDE_STRINGS) {
					continue;
				}
			}
			if (DUK_HSTRING_HAS_ARRIDX(k)) {
				/* This in currently only possible if the
				 * object has no array part: the array part
				 * is exhaustive when it is present.
				 */
#if !defined(DUK_USE_PREFER_SIZE)
				need_sort = 1;
#endif
			} else {
				if (enum_flags & DUK_ENUM_ARRAY_INDICES_ONLY) {
					continue;
				}
			}

			DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, curr, i) ||
			           !DUK_TVAL_IS_UNUSED(&DUK_HOBJECT_E_GET_VALUE_PTR(thr->heap, curr, i)->v));

			duk__add_enum_key(thr, k);

			/* [enum_target res] */
		}

		/* Sort enumerated keys according to ES2015 requirements for
		 * the "inheritance level" just processed.  This is far from
		 * optimal, ES2015 semantics could be achieved more efficiently
		 * by handling array index string keys (and symbol keys)
		 * specially above in effect doing the sort inline.
		 *
		 * Skip the sort if array index sorting is requested because
		 * we must consider all keys, also inherited, so an explicit
		 * sort is done for the whole result after we're done with the
		 * prototype chain.
		 *
		 * Also skip the sort if need_sort == 0, i.e. we know for
		 * certain that the enumerated order is already correct.
		 */
		sort_end_index = DUK_HOBJECT_GET_ENEXT(res);

		if (!(enum_flags & DUK_ENUM_SORT_ARRAY_INDICES)) {
#if defined(DUK_USE_PREFER_SIZE)
			duk__sort_enum_keys_es6(thr, res, (duk_int_fast32_t) sort_start_index, (duk_int_fast32_t) sort_end_index);
#else
			if (need_sort) {
				DUK_DDD(DUK_DDDPRINT("need to sort"));
				duk__sort_enum_keys_es6(thr, res, (duk_int_fast32_t) sort_start_index, (duk_int_fast32_t) sort_end_index);
			} else {
				DUK_DDD(DUK_DDDPRINT("no need to sort"));
			}
#endif
		}

		sort_start_index = sort_end_index;

		if (enum_flags & DUK_ENUM_OWN_PROPERTIES_ONLY) {
			break;
		}

		curr = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, curr);
	}

	/* [enum_target res] */

	duk_remove_m2(thr);

	/* [res] */

	if (enum_flags & DUK_ENUM_SORT_ARRAY_INDICES) {
		/* Some E5/E5.1 algorithms require that array indices are iterated
		 * in a strictly ascending order.  This is the case for e.g.
		 * Array.prototype.forEach() and JSON.stringify() PropertyList
		 * handling.  The caller can request an explicit sort in these
		 * cases.
		 */

		/* Sort to ES2015 order which works for pure array incides but
		 * also for mixed keys.
		 */
		duk__sort_enum_keys_es6(thr, res, (duk_int_fast32_t) DUK__ENUM_START_INDEX, (duk_int_fast32_t) DUK_HOBJECT_GET_ENEXT(res));
	}

#if defined(DUK_USE_ES6_PROXY)
 compact_and_return:
#endif
	/* compact; no need to seal because object is internal */
	duk_hobject_compact_props(thr, res);

	DUK_DDD(DUK_DDDPRINT("created enumerator object: %!iT", (duk_tval *) duk_get_tval(thr, -1)));
}

/*
 *  Returns non-zero if a key and/or value was enumerated, and:
 *
 *   [enum] -> [key]        (get_value == 0)
 *   [enum] -> [key value]  (get_value == 1)
 *
 *  Returns zero without pushing anything on the stack otherwise.
 */
DUK_INTERNAL duk_bool_t duk_hobject_enumerator_next(duk_hthread *thr, duk_bool_t get_value) {
	duk_hobject *e;
	duk_hobject *enum_target;
	duk_hstring *res = NULL;
	duk_uint_fast32_t idx;
	duk_bool_t check_existence;

	DUK_ASSERT(thr != NULL);

	/* [... enum] */

	e = duk_require_hobject(thr, -1);

	/* XXX use get tval ptr, more efficient */
	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_INT_NEXT);
	idx = (duk_uint_fast32_t) duk_require_uint(thr, -1);
	duk_pop(thr);
	DUK_DDD(DUK_DDDPRINT("enumeration: index is: %ld", (long) idx));

	/* Enumeration keys are checked against the enumeration target (to see
	 * that they still exist).  In the proxy enumeration case _Target will
	 * be the proxy, and checking key existence against the proxy is not
	 * required (or sensible, as the keys may be fully virtual).
	 */
	duk_xget_owndataprop_stridx_short(thr, -1, DUK_STRIDX_INT_TARGET);
	enum_target = duk_require_hobject(thr, -1);
	DUK_ASSERT(enum_target != NULL);
#if defined(DUK_USE_ES6_PROXY)
	check_existence = (!DUK_HOBJECT_IS_PROXY(enum_target));
#else
	check_existence = 1;
#endif
	duk_pop(thr);  /* still reachable */

	DUK_DDD(DUK_DDDPRINT("getting next enum value, enum_target=%!iO, enumerator=%!iT",
	                     (duk_heaphdr *) enum_target, (duk_tval *) duk_get_tval(thr, -1)));

	/* no array part */
	for (;;) {
		duk_hstring *k;

		if (idx >= DUK_HOBJECT_GET_ENEXT(e)) {
			DUK_DDD(DUK_DDDPRINT("enumeration: ran out of elements"));
			break;
		}

		/* we know these because enum objects are internally created */
		k = DUK_HOBJECT_E_GET_KEY(thr->heap, e, idx);
		DUK_ASSERT(k != NULL);
		DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, e, idx));
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(&DUK_HOBJECT_E_GET_VALUE(thr->heap, e, idx).v));

		idx++;

		/* recheck that the property still exists */
		if (check_existence && !duk_hobject_hasprop_raw(thr, enum_target, k)) {
			DUK_DDD(DUK_DDDPRINT("property deleted during enumeration, skip"));
			continue;
		}

		DUK_DDD(DUK_DDDPRINT("enumeration: found element, key: %!O", (duk_heaphdr *) k));
		res = k;
		break;
	}

	DUK_DDD(DUK_DDDPRINT("enumeration: updating next index to %ld", (long) idx));

	duk_push_u32(thr, (duk_uint32_t) idx);
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_INT_NEXT);

	/* [... enum] */

	if (res) {
		duk_push_hstring(thr, res);
		if (get_value) {
			duk_push_hobject(thr, enum_target);
			duk_dup_m2(thr);       /* -> [... enum key enum_target key] */
			duk_get_prop(thr, -2); /* -> [... enum key enum_target val] */
			duk_remove_m2(thr);    /* -> [... enum key val] */
			duk_remove(thr, -3);   /* -> [... key val] */
		} else {
			duk_remove_m2(thr);    /* -> [... key] */
		}
		return 1;
	} else {
		duk_pop(thr);  /* -> [...] */
		return 0;
	}
}

/*
 *  Get enumerated keys in an ECMAScript array.  Matches Object.keys() behavior
 *  described in E5 Section 15.2.3.14.
 */

DUK_INTERNAL duk_ret_t duk_hobject_get_enumerated_keys(duk_hthread *thr, duk_small_uint_t enum_flags) {
	duk_hobject *e;
	duk_hstring **keys;
	duk_tval *tv;
	duk_uint_fast32_t count;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(duk_get_hobject(thr, -1) != NULL);

	/* Create a temporary enumerator to get the (non-duplicated) key list;
	 * the enumerator state is initialized without being needed, but that
	 * has little impact.
	 */

	duk_hobject_enumerator_create(thr, enum_flags);
	e = duk_known_hobject(thr, -1);

	/* [enum_target enum res] */

	/* Create dense result array to exact size. */
	DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(e) >= DUK__ENUM_START_INDEX);
	count = (duk_uint32_t) (DUK_HOBJECT_GET_ENEXT(e) - DUK__ENUM_START_INDEX);

	/* XXX: uninit would be OK */
	tv = duk_push_harray_with_size_outptr(thr, (duk_uint32_t) count);
	DUK_ASSERT(count == 0 || tv != NULL);
	DUK_ASSERT(!duk_is_bare_object(thr, -1));

	/* Fill result array, no side effects. */

	keys = DUK_HOBJECT_E_GET_KEY_BASE(thr->heap, e);
	keys += DUK__ENUM_START_INDEX;

	while (count-- > 0) {
		duk_hstring *k;

		k = *keys++;
		DUK_ASSERT(k != NULL);  /* enumerator must have no keys deleted */

		DUK_TVAL_SET_STRING(tv, k);
		tv++;
		DUK_HSTRING_INCREF(thr, k);
	}

	/* [enum_target enum res] */
	duk_remove_m2(thr);

	/* [enum_target res] */

	return 1;  /* return 1 to allow callers to tail call */
}

/* automatic undefs */
#undef DUK__ENUM_START_INDEX
/*
 *  Misc support functions
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL duk_bool_t duk_hobject_prototype_chain_contains(duk_hthread *thr, duk_hobject *h, duk_hobject *p, duk_bool_t ignore_loop) {
	duk_uint_t sanity;

	DUK_ASSERT(thr != NULL);

	/* False if the object is NULL or the prototype 'p' is NULL.
	 * In particular, false if both are NULL (don't compare equal).
	 */
	if (h == NULL || p == NULL) {
		return 0;
	}

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (h == p) {
			return 1;
		}

		if (sanity-- == 0) {
			if (ignore_loop) {
				break;
			} else {
				DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
				DUK_WO_NORETURN(return 0;);
			}
		}
		h = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h);
	} while (h);

	return 0;
}

DUK_INTERNAL void duk_hobject_set_prototype_updref(duk_hthread *thr, duk_hobject *h, duk_hobject *p) {
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_hobject *tmp;

	DUK_ASSERT(h);
	tmp = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h);
	DUK_HOBJECT_SET_PROTOTYPE(thr->heap, h, p);
	DUK_HOBJECT_INCREF_ALLOWNULL(thr, p);  /* avoid problems if p == h->prototype */
	DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
#else
	DUK_ASSERT(h);
	DUK_UNREF(thr);
	DUK_HOBJECT_SET_PROTOTYPE(thr->heap, h, p);
#endif
}
/*
 *  Helpers for creating and querying pc2line debug data, which
 *  converts a bytecode program counter to a source line number.
 *
 *  The run-time pc2line data is bit-packed, and documented in:
 *
 *    doc/function-objects.rst
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_PC2LINE)

/* Generate pc2line data for an instruction sequence, leaving a buffer on stack top. */
DUK_INTERNAL void duk_hobject_pc2line_pack(duk_hthread *thr, duk_compiler_instr *instrs, duk_uint_fast32_t length) {
	duk_hbuffer_dynamic *h_buf;
	duk_bitencoder_ctx be_ctx_alloc;
	duk_bitencoder_ctx *be_ctx = &be_ctx_alloc;
	duk_uint32_t *hdr;
	duk_size_t new_size;
	duk_uint_fast32_t num_header_entries;
	duk_uint_fast32_t curr_offset;
	duk_int_fast32_t curr_line, next_line, diff_line;
	duk_uint_fast32_t curr_pc;
	duk_uint_fast32_t hdr_index;

	DUK_ASSERT(length <= DUK_COMPILER_MAX_BYTECODE_LENGTH);

	num_header_entries = (length + DUK_PC2LINE_SKIP - 1) / DUK_PC2LINE_SKIP;
	curr_offset = (duk_uint_fast32_t) (sizeof(duk_uint32_t) + num_header_entries * sizeof(duk_uint32_t) * 2);

	duk_push_dynamic_buffer(thr, (duk_size_t) curr_offset);
	h_buf = (duk_hbuffer_dynamic *) duk_known_hbuffer(thr, -1);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(h_buf) && !DUK_HBUFFER_HAS_EXTERNAL(h_buf));

	hdr = (duk_uint32_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, h_buf);
	DUK_ASSERT(hdr != NULL);
	hdr[0] = (duk_uint32_t) length;  /* valid pc range is [0, length[ */

	curr_pc = 0U;
	while (curr_pc < length) {
		new_size = (duk_size_t) (curr_offset + DUK_PC2LINE_MAX_DIFF_LENGTH);
		duk_hbuffer_resize(thr, h_buf, new_size);

		hdr = (duk_uint32_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, h_buf);
		DUK_ASSERT(hdr != NULL);
		DUK_ASSERT(curr_pc < length);
		hdr_index = 1 + (curr_pc / DUK_PC2LINE_SKIP) * 2;
		curr_line = (duk_int_fast32_t) instrs[curr_pc].line;
		hdr[hdr_index + 0] = (duk_uint32_t) curr_line;
		hdr[hdr_index + 1] = (duk_uint32_t) curr_offset;

#if 0
		DUK_DDD(DUK_DDDPRINT("hdr[%ld]: pc=%ld line=%ld offset=%ld",
		                     (long) (curr_pc / DUK_PC2LINE_SKIP),
		                     (long) curr_pc,
		                     (long) hdr[hdr_index + 0],
		                     (long) hdr[hdr_index + 1]));
#endif

		duk_memzero(be_ctx, sizeof(*be_ctx));
		be_ctx->data = ((duk_uint8_t *) hdr) + curr_offset;
		be_ctx->length = (duk_size_t) DUK_PC2LINE_MAX_DIFF_LENGTH;

		for (;;) {
			curr_pc++;
			if ( ((curr_pc % DUK_PC2LINE_SKIP) == 0) ||  /* end of diff run */
			     (curr_pc >= length) ) {                 /* end of bytecode */
				break;
			}
			DUK_ASSERT(curr_pc < length);
			next_line = (duk_int32_t) instrs[curr_pc].line;
			diff_line = next_line - curr_line;

#if 0
			DUK_DDD(DUK_DDDPRINT("curr_line=%ld, next_line=%ld -> diff_line=%ld",
			                     (long) curr_line, (long) next_line, (long) diff_line));
#endif

			if (diff_line == 0) {
				/* 0 */
				duk_be_encode(be_ctx, 0, 1);
			} else if (diff_line >= 1 && diff_line <= 4) {
				/* 1 0 <2 bits> */
				duk_be_encode(be_ctx, (duk_uint32_t) ((0x02 << 2) + (diff_line - 1)), 4);
			} else if (diff_line >= -0x80 && diff_line <= 0x7f) {
				/* 1 1 0 <8 bits> */
				DUK_ASSERT(diff_line + 0x80 >= 0 && diff_line + 0x80 <= 0xff);
				duk_be_encode(be_ctx, (duk_uint32_t) ((0x06 << 8) + (diff_line + 0x80)), 11);
			} else {
				/* 1 1 1 <32 bits>
				 * Encode in two parts to avoid bitencode 24-bit limitation
				 */
				duk_be_encode(be_ctx, (duk_uint32_t) ((0x07 << 16) + ((next_line >> 16) & 0xffff)), 19);
				duk_be_encode(be_ctx, (duk_uint32_t) (next_line & 0xffff), 16);
			}

			curr_line = next_line;
		}

		duk_be_finish(be_ctx);
		DUK_ASSERT(!be_ctx->truncated);

		/* be_ctx->offset == length of encoded bitstream */
		curr_offset += (duk_uint_fast32_t) be_ctx->offset;
	}

	/* compact */
	new_size = (duk_size_t) curr_offset;
	duk_hbuffer_resize(thr, h_buf, new_size);

	(void) duk_to_fixed_buffer(thr, -1, NULL);

	DUK_DDD(DUK_DDDPRINT("final pc2line data: pc_limit=%ld, length=%ld, %lf bits/opcode --> %!ixT",
	                     (long) length, (long) new_size, (double) new_size * 8.0 / (double) length,
	                     (duk_tval *) duk_get_tval(thr, -1)));
}

/* PC is unsigned.  If caller does PC arithmetic and gets a negative result,
 * it will map to a large PC which is out of bounds and causes a zero to be
 * returned.
 */
DUK_LOCAL duk_uint_fast32_t duk__hobject_pc2line_query_raw(duk_hthread *thr, duk_hbuffer_fixed *buf, duk_uint_fast32_t pc) {
	duk_bitdecoder_ctx bd_ctx_alloc;
	duk_bitdecoder_ctx *bd_ctx = &bd_ctx_alloc;
	duk_uint32_t *hdr;
	duk_uint_fast32_t start_offset;
	duk_uint_fast32_t pc_limit;
	duk_uint_fast32_t hdr_index;
	duk_uint_fast32_t pc_base;
	duk_uint_fast32_t n;
	duk_uint_fast32_t curr_line;

	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(!DUK_HBUFFER_HAS_DYNAMIC((duk_hbuffer *) buf) && !DUK_HBUFFER_HAS_EXTERNAL((duk_hbuffer *) buf));
	DUK_UNREF(thr);

	/*
	 *  Use the index in the header to find the right starting point
	 */

	hdr_index = pc / DUK_PC2LINE_SKIP;
	pc_base = hdr_index * DUK_PC2LINE_SKIP;
	n = pc - pc_base;

	if (DUK_HBUFFER_FIXED_GET_SIZE(buf) <= sizeof(duk_uint32_t)) {
		DUK_DD(DUK_DDPRINT("pc2line lookup failed: buffer is smaller than minimal header"));
		goto pc2line_error;
	}

	hdr = (duk_uint32_t *) (void *) DUK_HBUFFER_FIXED_GET_DATA_PTR(thr->heap, buf);
	pc_limit = hdr[0];
	if (pc >= pc_limit) {
		/* Note: pc is unsigned and cannot be negative */
		DUK_DD(DUK_DDPRINT("pc2line lookup failed: pc out of bounds (pc=%ld, limit=%ld)",
		                   (long) pc, (long) pc_limit));
		goto pc2line_error;
	}

	curr_line = hdr[1 + hdr_index * 2];
	start_offset = hdr[1 + hdr_index * 2 + 1];
	if ((duk_size_t) start_offset > DUK_HBUFFER_FIXED_GET_SIZE(buf)) {
		DUK_DD(DUK_DDPRINT("pc2line lookup failed: start_offset out of bounds (start_offset=%ld, buffer_size=%ld)",
		                   (long) start_offset, (long) DUK_HBUFFER_GET_SIZE((duk_hbuffer *) buf)));
		goto pc2line_error;
	}

	/*
	 *  Iterate the bitstream (line diffs) until PC is reached
	 */

	duk_memzero(bd_ctx, sizeof(*bd_ctx));
	bd_ctx->data = ((duk_uint8_t *) hdr) + start_offset;
	bd_ctx->length = (duk_size_t) (DUK_HBUFFER_FIXED_GET_SIZE(buf) - start_offset);

#if 0
	DUK_DDD(DUK_DDDPRINT("pc2line lookup: pc=%ld -> hdr_index=%ld, pc_base=%ld, n=%ld, start_offset=%ld",
	                     (long) pc, (long) hdr_index, (long) pc_base, (long) n, (long) start_offset));
#endif

	while (n > 0) {
#if 0
		DUK_DDD(DUK_DDDPRINT("lookup: n=%ld, curr_line=%ld", (long) n, (long) curr_line));
#endif

		if (duk_bd_decode_flag(bd_ctx)) {
			if (duk_bd_decode_flag(bd_ctx)) {
				if (duk_bd_decode_flag(bd_ctx)) {
					/* 1 1 1 <32 bits> */
					duk_uint_fast32_t t;
					t = duk_bd_decode(bd_ctx, 16);  /* workaround: max nbits = 24 now */
					t = (t << 16) + duk_bd_decode(bd_ctx, 16);
					curr_line = t;
				} else {
					/* 1 1 0 <8 bits> */
					duk_uint_fast32_t t;
					t = duk_bd_decode(bd_ctx, 8);
					curr_line = curr_line + t - 0x80;
				}
			} else {
				/* 1 0 <2 bits> */
				duk_uint_fast32_t t;
				t = duk_bd_decode(bd_ctx, 2);
				curr_line = curr_line + t + 1;
			}
		} else {
			/* 0: no change */
		}

		n--;
	}

	DUK_DDD(DUK_DDDPRINT("pc2line lookup result: pc %ld -> line %ld", (long) pc, (long) curr_line));
	return curr_line;

 pc2line_error:
	DUK_D(DUK_DPRINT("pc2line conversion failed for pc=%ld", (long) pc));
	return 0;
}

DUK_INTERNAL duk_uint_fast32_t duk_hobject_pc2line_query(duk_hthread *thr, duk_idx_t idx_func, duk_uint_fast32_t pc) {
	duk_hbuffer_fixed *pc2line;
	duk_uint_fast32_t line;

	/* XXX: now that pc2line is used by the debugger quite heavily in
	 * checked execution, this should be optimized to avoid value stack
	 * and perhaps also implement some form of pc2line caching (see
	 * future work in debugger.rst).
	 */

	duk_xget_owndataprop_stridx_short(thr, idx_func, DUK_STRIDX_INT_PC2LINE);
	pc2line = (duk_hbuffer_fixed *) (void *) duk_get_hbuffer(thr, -1);
	if (pc2line != NULL) {
		DUK_ASSERT(!DUK_HBUFFER_HAS_DYNAMIC((duk_hbuffer *) pc2line) && !DUK_HBUFFER_HAS_EXTERNAL((duk_hbuffer *) pc2line));
		line = duk__hobject_pc2line_query_raw(thr, pc2line, (duk_uint_fast32_t) pc);
	} else {
		line = 0;
	}
	duk_pop(thr);

	return line;
}

#endif  /* DUK_USE_PC2LINE */
/*
 *  duk_hobject property access functionality.
 *
 *  This is very central functionality for size, performance, and compliance.
 *  It is also rather intricate; see hobject-algorithms.rst for discussion on
 *  the algorithms and memory-management.rst for discussion on refcounts and
 *  side effect issues.
 *
 *  Notes:
 *
 *    - It might be tempting to assert "refcount nonzero" for objects
 *      being operated on, but that's not always correct: objects with
 *      a zero refcount may be operated on by the refcount implementation
 *      (finalization) for instance.  Hence, no refcount assertions are made.
 *
 *    - Many operations (memory allocation, identifier operations, etc)
 *      may cause arbitrary side effects (e.g. through GC and finalization).
 *      These side effects may invalidate duk_tval pointers which point to
 *      areas subject to reallocation (like value stack).  Heap objects
 *      themselves have stable pointers.  Holding heap object pointers or
 *      duk_tval copies is not problematic with respect to side effects;
 *      care must be taken when holding and using argument duk_tval pointers.
 *
 *    - If a finalizer is executed, it may operate on the the same object
 *      we're currently dealing with.  For instance, the finalizer might
 *      delete a certain property which has already been looked up and
 *      confirmed to exist.  Ideally finalizers would be disabled if GC
 *      happens during property access.  At the moment property table realloc
 *      disables finalizers, and all DECREFs may cause arbitrary changes so
 *      handle DECREF carefully.
 *
 *    - The order of operations for a DECREF matters.  When DECREF is executed,
 *      the entire object graph must be consistent; note that a refzero may
 *      lead to a mark-and-sweep through a refcount finalizer.  Use NORZ macros
 *      and an explicit DUK_REFZERO_CHECK_xxx() if achieving correct order is hard.
 */

/*
 *  XXX: array indices are mostly typed as duk_uint32_t here; duk_uarridx_t
 *  might be more appropriate.
 */

/* #include duk_internal.h -> already included */

/*
 *  Local defines
 */

#define DUK__NO_ARRAY_INDEX             DUK_HSTRING_NO_ARRAY_INDEX

/* Marker values for hash part. */
#define DUK__HASH_UNUSED                DUK_HOBJECT_HASHIDX_UNUSED
#define DUK__HASH_DELETED               DUK_HOBJECT_HASHIDX_DELETED

/* Valstack space that suffices for all local calls, excluding any recursion
 * into ECMAScript or Duktape/C calls (Proxy, getters, etc).
 */
#define DUK__VALSTACK_SPACE             10

/* Valstack space allocated especially for proxy lookup which does a
 * recursive property lookup.
 */
#define DUK__VALSTACK_PROXY_LOOKUP      20

/*
 *  Local prototypes
 */

DUK_LOCAL_DECL duk_bool_t duk__check_arguments_map_for_get(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc);
DUK_LOCAL_DECL void duk__check_arguments_map_for_put(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc, duk_bool_t throw_flag);
DUK_LOCAL_DECL void duk__check_arguments_map_for_delete(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc);

DUK_LOCAL_DECL duk_bool_t duk__handle_put_array_length_smaller(duk_hthread *thr, duk_hobject *obj, duk_uint32_t old_len, duk_uint32_t new_len, duk_bool_t force_flag, duk_uint32_t *out_result_len);
DUK_LOCAL_DECL duk_bool_t duk__handle_put_array_length(duk_hthread *thr, duk_hobject *obj);

DUK_LOCAL_DECL duk_bool_t duk__get_propdesc(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *out_desc, duk_small_uint_t flags);
DUK_LOCAL_DECL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_uint32_t arr_idx, duk_propdesc *out_desc, duk_small_uint_t flags);

DUK_LOCAL_DECL void duk__abandon_array_part(duk_hthread *thr, duk_hobject *obj);
DUK_LOCAL_DECL void duk__grow_props_for_array_item(duk_hthread *thr, duk_hobject *obj, duk_uint32_t highest_arr_idx);

/*
 *  Misc helpers
 */

/* Convert a duk_tval number (caller checks) to a 32-bit index.  Returns
 * DUK__NO_ARRAY_INDEX if the number is not whole or not a valid array
 * index.
 */
/* XXX: for fastints, could use a variant which assumes a double duk_tval
 * (and doesn't need to check for fastint again).
 */
DUK_LOCAL duk_uint32_t duk__tval_number_to_arr_idx(duk_tval *tv) {
	duk_double_t dbl;
	duk_uint32_t idx;

	DUK_ASSERT(tv != NULL);
	DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));

	/* -0 is accepted here as index 0 because ToString(-0) == "0" which is
	 * in canonical form and thus an array index.
	 */
	dbl = DUK_TVAL_GET_NUMBER(tv);
	idx = (duk_uint32_t) dbl;
	if (duk_double_equals((duk_double_t) idx, dbl)) {
	        /* Is whole and within 32 bit range.  If the value happens to be 0xFFFFFFFF,
		 * it's not a valid array index but will then match DUK__NO_ARRAY_INDEX.
		 */
		return idx;
	}
	return DUK__NO_ARRAY_INDEX;
}

#if defined(DUK_USE_FASTINT)
/* Convert a duk_tval fastint (caller checks) to a 32-bit index. */
DUK_LOCAL duk_uint32_t duk__tval_fastint_to_arr_idx(duk_tval *tv) {
	duk_int64_t t;

	DUK_ASSERT(tv != NULL);
	DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv));

	t = DUK_TVAL_GET_FASTINT(tv);
	if (((duk_uint64_t) t & ~DUK_U64_CONSTANT(0xffffffff)) != 0) {
		/* Catches >0x100000000 and negative values. */
		return DUK__NO_ARRAY_INDEX;
	}

	/* If the value happens to be 0xFFFFFFFF, it's not a valid array index
	 * but will then match DUK__NO_ARRAY_INDEX.
	 */
	return (duk_uint32_t) t;
}
#endif  /* DUK_USE_FASTINT */

/* Convert a duk_tval on the value stack (in a trusted index we don't validate)
 * to a string or symbol using ES2015 ToPropertyKey():
 * http://www.ecma-international.org/ecma-262/6.0/#sec-topropertykey.
 *
 * Also check if it's a valid array index and return that (or DUK__NO_ARRAY_INDEX
 * if not).
 */
DUK_LOCAL duk_uint32_t duk__to_property_key(duk_hthread *thr, duk_idx_t idx, duk_hstring **out_h) {
	duk_uint32_t arr_idx;
	duk_hstring *h;
	duk_tval *tv_dst;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(out_h != NULL);
	DUK_ASSERT(duk_is_valid_index(thr, idx));
	DUK_ASSERT(idx < 0);

	/* XXX: The revised ES2015 ToPropertyKey() handling (ES5.1 was just
	 * ToString()) involves a ToPrimitive(), a symbol check, and finally
	 * a ToString().  Figure out the best way to have a good fast path
	 * but still be compliant and share code.
	 */

	tv_dst = DUK_GET_TVAL_NEGIDX(thr, idx);  /* intentionally unvalidated */
	if (DUK_TVAL_IS_STRING(tv_dst)) {
		/* Most important path: strings and plain symbols are used as
		 * is.  For symbols the array index check below is unnecessary
		 * (they're never valid array indices) but checking that the
		 * string is a symbol would make the plain string path slower
		 * unnecessarily.
		 */
		h = DUK_TVAL_GET_STRING(tv_dst);
	} else {
		h = duk_to_property_key_hstring(thr, idx);
	}
	DUK_ASSERT(h != NULL);
	*out_h = h;

	arr_idx = DUK_HSTRING_GET_ARRIDX_FAST(h);
	return arr_idx;
}

DUK_LOCAL duk_uint32_t duk__push_tval_to_property_key(duk_hthread *thr, duk_tval *tv_key, duk_hstring **out_h) {
	duk_push_tval(thr, tv_key);  /* XXX: could use an unsafe push here */
	return duk__to_property_key(thr, -1, out_h);
}

/* String is an own (virtual) property of a plain buffer. */
DUK_LOCAL duk_bool_t duk__key_is_plain_buf_ownprop(duk_hthread *thr, duk_hbuffer *buf, duk_hstring *key, duk_uint32_t arr_idx) {
	DUK_UNREF(thr);

	/* Virtual index properties.  Checking explicitly for
	 * 'arr_idx != DUK__NO_ARRAY_INDEX' is not necessary
	 * because DUK__NO_ARRAY_INDEXi is always larger than
	 * maximum allowed buffer size.
	 */
	DUK_ASSERT(DUK__NO_ARRAY_INDEX >= DUK_HBUFFER_GET_SIZE(buf));
	if (arr_idx < DUK_HBUFFER_GET_SIZE(buf)) {
		return 1;
	}

	/* Other virtual properties. */
	return (key == DUK_HTHREAD_STRING_LENGTH(thr));
}

/*
 *  Helpers for managing property storage size
 */

/* Get default hash part size for a certain entry part size. */
#if defined(DUK_USE_HOBJECT_HASH_PART)
DUK_LOCAL duk_uint32_t duk__get_default_h_size(duk_uint32_t e_size) {
	DUK_ASSERT(e_size <= DUK_HOBJECT_MAX_PROPERTIES);

	if (e_size >= DUK_USE_HOBJECT_HASH_PROP_LIMIT) {
		duk_uint32_t res;
		duk_uint32_t tmp;

		/* Hash size should be 2^N where N is chosen so that 2^N is
		 * larger than e_size.  Extra shifting is used to ensure hash
		 * is relatively sparse.
		 */
		tmp = e_size;
		res = 2;  /* Result will be 2 ** (N + 1). */
		while (tmp >= 0x40) {
			tmp >>= 6;
			res <<= 6;
		}
		while (tmp != 0) {
			tmp >>= 1;
			res <<= 1;
		}
		DUK_ASSERT((DUK_HOBJECT_MAX_PROPERTIES << 2U) > DUK_HOBJECT_MAX_PROPERTIES);  /* Won't wrap, even shifted by 2. */
		DUK_ASSERT(res > e_size);
		return res;
	} else {
		return 0;
	}
}
#endif  /* USE_PROP_HASH_PART */

/* Get minimum entry part growth for a certain size. */
DUK_LOCAL duk_uint32_t duk__get_min_grow_e(duk_uint32_t e_size) {
	duk_uint32_t res;

	res = (e_size + DUK_USE_HOBJECT_ENTRY_MINGROW_ADD) / DUK_USE_HOBJECT_ENTRY_MINGROW_DIVISOR;
	DUK_ASSERT(res >= 1);  /* important for callers */
	return res;
}

/* Get minimum array part growth for a certain size. */
DUK_LOCAL duk_uint32_t duk__get_min_grow_a(duk_uint32_t a_size) {
	duk_uint32_t res;

	res = (a_size + DUK_USE_HOBJECT_ARRAY_MINGROW_ADD) / DUK_USE_HOBJECT_ARRAY_MINGROW_DIVISOR;
	DUK_ASSERT(res >= 1);  /* important for callers */
	return res;
}

/* Count actually used entry part entries (non-NULL keys). */
DUK_LOCAL duk_uint32_t duk__count_used_e_keys(duk_hthread *thr, duk_hobject *obj) {
	duk_uint_fast32_t i;
	duk_uint_fast32_t n = 0;
	duk_hstring **e;

	DUK_ASSERT(obj != NULL);
	DUK_UNREF(thr);

	e = DUK_HOBJECT_E_GET_KEY_BASE(thr->heap, obj);
	for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
		if (*e++) {
			n++;
		}
	}
	return (duk_uint32_t) n;
}

/* Count actually used array part entries and array minimum size.
 * NOTE: 'out_min_size' can be computed much faster by starting from the
 * end and breaking out early when finding first used entry, but this is
 * not needed now.
 */
DUK_LOCAL void duk__compute_a_stats(duk_hthread *thr, duk_hobject *obj, duk_uint32_t *out_used, duk_uint32_t *out_min_size) {
	duk_uint_fast32_t i;
	duk_uint_fast32_t used = 0;
	duk_uint_fast32_t highest_idx = (duk_uint_fast32_t) -1;  /* see below */
	duk_tval *a;

	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(out_used != NULL);
	DUK_ASSERT(out_min_size != NULL);
	DUK_UNREF(thr);

	a = DUK_HOBJECT_A_GET_BASE(thr->heap, obj);
	for (i = 0; i < DUK_HOBJECT_GET_ASIZE(obj); i++) {
		duk_tval *tv = a++;
		if (!DUK_TVAL_IS_UNUSED(tv)) {
			used++;
			highest_idx = i;
		}
	}

	/* Initial value for highest_idx is -1 coerced to unsigned.  This
	 * is a bit odd, but (highest_idx + 1) will then wrap to 0 below
	 * for out_min_size as intended.
	 */

	*out_used = (duk_uint32_t) used;
	*out_min_size = (duk_uint32_t) (highest_idx + 1);  /* 0 if no used entries */
}

/* Check array density and indicate whether or not the array part should be abandoned. */
DUK_LOCAL duk_bool_t duk__abandon_array_density_check(duk_uint32_t a_used, duk_uint32_t a_size) {
	/*
	 *  Array abandon check; abandon if:
	 *
	 *    new_used / new_size < limit
	 *    new_used < limit * new_size        || limit is 3 bits fixed point
	 *    new_used < limit' / 8 * new_size   || *8
	 *    8*new_used < limit' * new_size     || :8
	 *    new_used < limit' * (new_size / 8)
	 *
	 *  Here, new_used = a_used, new_size = a_size.
	 *
	 *  Note: some callers use approximate values for a_used and/or a_size
	 *  (e.g. dropping a '+1' term).  This doesn't affect the usefulness
	 *  of the check, but may confuse debugging.
	 */

	return (a_used < DUK_USE_HOBJECT_ARRAY_ABANDON_LIMIT * (a_size >> 3));
}

/* Fast check for extending array: check whether or not a slow density check is required. */
DUK_LOCAL duk_bool_t duk__abandon_array_slow_check_required(duk_uint32_t arr_idx, duk_uint32_t old_size) {
	duk_uint32_t new_size_min;

	/*
	 *  In a fast check we assume old_size equals old_used (i.e., existing
	 *  array is fully dense).
	 *
	 *  Slow check if:
	 *
	 *    (new_size - old_size) / old_size > limit
	 *    new_size - old_size > limit * old_size
	 *    new_size > (1 + limit) * old_size        || limit' is 3 bits fixed point
	 *    new_size > (1 + (limit' / 8)) * old_size || * 8
	 *    8 * new_size > (8 + limit') * old_size   || : 8
	 *    new_size > (8 + limit') * (old_size / 8)
	 *    new_size > limit'' * (old_size / 8)      || limit'' = 9 -> max 25% increase
	 *    arr_idx + 1 > limit'' * (old_size / 8)
	 *
	 *  This check doesn't work well for small values, so old_size is rounded
	 *  up for the check (and the '+ 1' of arr_idx can be ignored in practice):
	 *
	 *    arr_idx > limit'' * ((old_size + 7) / 8)
	 */

	new_size_min = arr_idx + 1;
	return (new_size_min >= DUK_USE_HOBJECT_ARRAY_ABANDON_MINSIZE) &&
	       (arr_idx > DUK_USE_HOBJECT_ARRAY_FAST_RESIZE_LIMIT * ((old_size + 7) >> 3));
}

DUK_LOCAL duk_bool_t duk__abandon_array_check(duk_hthread *thr, duk_uint32_t arr_idx, duk_hobject *obj) {
	duk_uint32_t min_size;
	duk_uint32_t old_used;
	duk_uint32_t old_size;

	if (!duk__abandon_array_slow_check_required(arr_idx, DUK_HOBJECT_GET_ASIZE(obj))) {
		DUK_DDD(DUK_DDDPRINT("=> fast resize is OK"));
		return 0;
	}

	duk__compute_a_stats(thr, obj, &old_used, &old_size);

	DUK_DDD(DUK_DDDPRINT("abandon check, array stats: old_used=%ld, old_size=%ld, arr_idx=%ld",
	                     (long) old_used, (long) old_size, (long) arr_idx));

	min_size = arr_idx + 1;
#if defined(DUK_USE_OBJSIZES16)
	if (min_size > DUK_UINT16_MAX) {
		goto do_abandon;
	}
#endif
	DUK_UNREF(min_size);

	/* Note: intentionally use approximations to shave a few instructions:
	 *   a_used = old_used  (accurate: old_used + 1)
	 *   a_size = arr_idx   (accurate: arr_idx + 1)
	 */
	if (duk__abandon_array_density_check(old_used, arr_idx)) {
		DUK_DD(DUK_DDPRINT("write to new array entry beyond current length, "
		                   "decided to abandon array part (would become too sparse)"));

		/* Abandoning requires a props allocation resize and
		 * 'rechecks' the valstack, invalidating any existing
		 * valstack value pointers.
		 */
		goto do_abandon;
	}

	DUK_DDD(DUK_DDDPRINT("=> decided to keep array part"));
	return 0;

 do_abandon:
	duk__abandon_array_part(thr, obj);
	DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(obj));
	return 1;
}

DUK_LOCAL duk_tval *duk__obtain_arridx_slot_slowpath(duk_hthread *thr, duk_uint32_t arr_idx, duk_hobject *obj) {
	/*
	 *  Array needs to grow, but we don't want it becoming too sparse.
	 *  If it were to become sparse, abandon array part, moving all
	 *  array entries into the entries part (for good).
	 *
	 *  Since we don't keep track of actual density (used vs. size) of
	 *  the array part, we need to estimate somehow.  The check is made
	 *  in two parts:
	 *
	 *    - Check whether the resize need is small compared to the
	 *      current size (relatively); if so, resize without further
	 *      checking (essentially we assume that the original part is
	 *      "dense" so that the result would be dense enough).
	 *
	 *    - Otherwise, compute the resize using an actual density
	 *      measurement based on counting the used array entries.
	 */

	DUK_DDD(DUK_DDDPRINT("write to new array requires array resize, decide whether to do a "
	                     "fast resize without abandon check (arr_idx=%ld, old_size=%ld)",
	                     (long) arr_idx, (long) DUK_HOBJECT_GET_ASIZE(obj)));

	if (DUK_UNLIKELY(duk__abandon_array_check(thr, arr_idx, obj) != 0)) {
		DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(obj));
		return NULL;
	}

	DUK_DD(DUK_DDPRINT("write to new array entry beyond current length, "
	                   "decided to extend current allocation"));

	/* In principle it's possible to run out of memory extending the
	 * array but with the allocation going through if we were to abandon
	 * the array part and try again.  In practice this should be rare
	 * because abandoned arrays have a higher per-entry footprint.
	 */

	duk__grow_props_for_array_item(thr, obj, arr_idx);

	DUK_ASSERT(DUK_HOBJECT_HAS_ARRAY_PART(obj));
	DUK_ASSERT(arr_idx < DUK_HOBJECT_GET_ASIZE(obj));
	return DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
}

DUK_LOCAL DUK_INLINE duk_tval *duk__obtain_arridx_slot(duk_hthread *thr, duk_uint32_t arr_idx, duk_hobject *obj) {
	if (DUK_LIKELY(arr_idx < DUK_HOBJECT_GET_ASIZE(obj))) {
		return DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
	} else {
		return duk__obtain_arridx_slot_slowpath(thr, arr_idx, obj);
	}
}

/*
 *  Proxy helpers
 */

#if defined(DUK_USE_ES6_PROXY)
DUK_INTERNAL duk_bool_t duk_hobject_proxy_check(duk_hobject *obj, duk_hobject **out_target, duk_hobject **out_handler) {
	duk_hproxy *h_proxy;

	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(out_target != NULL);
	DUK_ASSERT(out_handler != NULL);

	/* Caller doesn't need to check exotic proxy behavior (but does so for
	 * some fast paths).
	 */
	if (DUK_LIKELY(!DUK_HOBJECT_IS_PROXY(obj))) {
		return 0;
	}
	h_proxy = (duk_hproxy *) obj;
	DUK_HPROXY_ASSERT_VALID(h_proxy);

	DUK_ASSERT(h_proxy->handler != NULL);
	DUK_ASSERT(h_proxy->target != NULL);
	*out_handler = h_proxy->handler;
	*out_target = h_proxy->target;

	return 1;
}
#endif  /* DUK_USE_ES6_PROXY */

/* Get Proxy target object.  If the argument is not a Proxy, return it as is.
 * If a Proxy is revoked, an error is thrown.
 */
#if defined(DUK_USE_ES6_PROXY)
DUK_INTERNAL duk_hobject *duk_hobject_resolve_proxy_target(duk_hobject *obj) {
	DUK_ASSERT(obj != NULL);

	/* Resolve Proxy targets until Proxy chain ends.  No explicit check for
	 * a Proxy loop: user code cannot create such a loop (it would only be
	 * possible by editing duk_hproxy references directly).
	 */

	while (DUK_HOBJECT_IS_PROXY(obj)) {
		duk_hproxy *h_proxy;

		h_proxy = (duk_hproxy *) obj;
		DUK_HPROXY_ASSERT_VALID(h_proxy);
		obj = h_proxy->target;
		DUK_ASSERT(obj != NULL);
	}

	DUK_ASSERT(obj != NULL);
	return obj;
}
#endif  /* DUK_USE_ES6_PROXY */

#if defined(DUK_USE_ES6_PROXY)
DUK_LOCAL duk_bool_t duk__proxy_check_prop(duk_hthread *thr, duk_hobject *obj, duk_small_uint_t stridx_trap, duk_tval *tv_key, duk_hobject **out_target) {
	duk_hobject *h_handler;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(tv_key != NULL);
	DUK_ASSERT(out_target != NULL);

	if (!duk_hobject_proxy_check(obj, out_target, &h_handler)) {
		return 0;
	}
	DUK_ASSERT(*out_target != NULL);
	DUK_ASSERT(h_handler != NULL);

	/* XXX: At the moment Duktape accesses internal keys like _Finalizer using a
	 * normal property set/get which would allow a proxy handler to interfere with
	 * such behavior and to get access to internal key strings.  This is not a problem
	 * as such because internal key strings can be created in other ways too (e.g.
	 * through buffers).  The best fix is to change Duktape internal lookups to
	 * skip proxy behavior.  Until that, internal property accesses bypass the
	 * proxy and are applied to the target (as if the handler did not exist).
	 * This has some side effects, see test-bi-proxy-internal-keys.js.
	 */

	if (DUK_TVAL_IS_STRING(tv_key)) {
		duk_hstring *h_key = (duk_hstring *) DUK_TVAL_GET_STRING(tv_key);
		DUK_ASSERT(h_key != NULL);
		if (DUK_HSTRING_HAS_HIDDEN(h_key)) {
			/* Symbol accesses must go through proxy lookup in ES2015.
			 * Hidden symbols behave like Duktape 1.x internal keys
			 * and currently won't.
			 */
			DUK_DDD(DUK_DDDPRINT("hidden key, skip proxy handler and apply to target"));
			return 0;
		}
	}

	/* The handler is looked up with a normal property lookup; it may be an
	 * accessor or the handler object itself may be a proxy object.  If the
	 * handler is a proxy, we need to extend the valstack as we make a
	 * recursive proxy check without a function call in between (in fact
	 * there is no limit to the potential recursion here).
	 *
	 * (For sanity, proxy creation rejects another proxy object as either
	 * the handler or the target at the moment so recursive proxy cases
	 * are not realized now.)
	 */

	/* XXX: C recursion limit if proxies are allowed as handler/target values */

	duk_require_stack(thr, DUK__VALSTACK_PROXY_LOOKUP);
	duk_push_hobject(thr, h_handler);
	if (duk_get_prop_stridx_short(thr, -1, stridx_trap)) {
		/* -> [ ... handler trap ] */
		duk_insert(thr, -2);  /* -> [ ... trap handler ] */

		/* stack prepped for func call: [ ... trap handler ] */
		return 1;
	} else {
		duk_pop_2_unsafe(thr);
		return 0;
	}
}
#endif  /* DUK_USE_ES6_PROXY */

/*
 *  Reallocate property allocation, moving properties to the new allocation.
 *
 *  Includes key compaction, rehashing, and can also optionally abandon
 *  the array part, 'migrating' array entries into the beginning of the
 *  new entry part.
 *
 *  There is no support for in-place reallocation or just compacting keys
 *  without resizing the property allocation.  This is intentional to keep
 *  code size minimal, but would be useful future work.
 *
 *  The implementation is relatively straightforward, except for the array
 *  abandonment process.  Array abandonment requires that new string keys
 *  are interned, which may trigger GC.  All keys interned so far must be
 *  reachable for GC at all times and correctly refcounted for; valstack is
 *  used for that now.
 *
 *  Also, a GC triggered during this reallocation process must not interfere
 *  with the object being resized.  This is currently controlled by preventing
 *  finalizers (as they may affect ANY object) and object compaction in
 *  mark-and-sweep.  It would suffice to protect only this particular object
 *  from compaction, however.  DECREF refzero cascades are side effect free
 *  and OK.
 *
 *  Note: because we need to potentially resize the valstack (as part
 *  of abandoning the array part), any tval pointers to the valstack
 *  will become invalid after this call.
 */

DUK_INTERNAL void duk_hobject_realloc_props(duk_hthread *thr,
                                            duk_hobject *obj,
                                            duk_uint32_t new_e_size,
                                            duk_uint32_t new_a_size,
                                            duk_uint32_t new_h_size,
                                            duk_bool_t abandon_array) {
	duk_small_uint_t prev_ms_base_flags;
	duk_uint32_t new_alloc_size;
	duk_uint32_t new_e_size_adjusted;
	duk_uint8_t *new_p;
	duk_hstring **new_e_k;
	duk_propvalue *new_e_pv;
	duk_uint8_t *new_e_f;
	duk_tval *new_a;
	duk_uint32_t *new_h;
	duk_uint32_t new_e_next;
	duk_uint_fast32_t i;
	duk_size_t array_copy_size;
#if defined(DUK_USE_ASSERTIONS)
	duk_bool_t prev_error_not_allowed;
#endif

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(!abandon_array || new_a_size == 0);  /* if abandon_array, new_a_size must be 0 */
	DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, obj) != NULL || (DUK_HOBJECT_GET_ESIZE(obj) == 0 && DUK_HOBJECT_GET_ASIZE(obj) == 0));
	DUK_ASSERT(new_h_size == 0 || new_h_size >= new_e_size);  /* required to guarantee success of rehashing,
	                                                           * intentionally use unadjusted new_e_size
	                                                           */
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_STATS_INC(thr->heap, stats_object_realloc_props);

	/*
	 *  Pre resize assertions.
	 */

#if defined(DUK_USE_ASSERTIONS)
	/* XXX: pre-checks (such as no duplicate keys) */
#endif

	/*
	 *  For property layout 1, tweak e_size to ensure that the whole entry
	 *  part (key + val + flags) is a suitable multiple for alignment
	 *  (platform specific).
	 *
	 *  Property layout 2 does not require this tweaking and is preferred
	 *  on low RAM platforms requiring alignment.
	 */

#if defined(DUK_USE_HOBJECT_LAYOUT_2) || defined(DUK_USE_HOBJECT_LAYOUT_3)
	DUK_DDD(DUK_DDDPRINT("using layout 2 or 3, no need to pad e_size: %ld", (long) new_e_size));
	new_e_size_adjusted = new_e_size;
#elif defined(DUK_USE_HOBJECT_LAYOUT_1) && (DUK_HOBJECT_ALIGN_TARGET == 1)
	DUK_DDD(DUK_DDDPRINT("using layout 1, but no need to pad e_size: %ld", (long) new_e_size));
	new_e_size_adjusted = new_e_size;
#elif defined(DUK_USE_HOBJECT_LAYOUT_1) && ((DUK_HOBJECT_ALIGN_TARGET == 4) || (DUK_HOBJECT_ALIGN_TARGET == 8))
	new_e_size_adjusted = (new_e_size + (duk_uint32_t) DUK_HOBJECT_ALIGN_TARGET - 1U) &
	                      (~((duk_uint32_t) DUK_HOBJECT_ALIGN_TARGET - 1U));
	DUK_DDD(DUK_DDDPRINT("using layout 1, and alignment target is %ld, adjusted e_size: %ld -> %ld",
	                     (long) DUK_HOBJECT_ALIGN_TARGET, (long) new_e_size, (long) new_e_size_adjusted));
	DUK_ASSERT(new_e_size_adjusted >= new_e_size);
#else
#error invalid hobject layout defines
#endif

	/*
	 *  Debug logging after adjustment.
	 */

	DUK_DDD(DUK_DDDPRINT("attempt to resize hobject %p props (%ld -> %ld bytes), from {p=%p,e_size=%ld,e_next=%ld,a_size=%ld,h_size=%ld} to "
	                     "{e_size=%ld,a_size=%ld,h_size=%ld}, abandon_array=%ld, unadjusted new_e_size=%ld",
	                     (void *) obj,
	                     (long) DUK_HOBJECT_P_COMPUTE_SIZE(DUK_HOBJECT_GET_ESIZE(obj),
	                                                       DUK_HOBJECT_GET_ASIZE(obj),
	                                                       DUK_HOBJECT_GET_HSIZE(obj)),
	                     (long) DUK_HOBJECT_P_COMPUTE_SIZE(new_e_size_adjusted, new_a_size, new_h_size),
	                     (void *) DUK_HOBJECT_GET_PROPS(thr->heap, obj),
	                     (long) DUK_HOBJECT_GET_ESIZE(obj),
	                     (long) DUK_HOBJECT_GET_ENEXT(obj),
	                     (long) DUK_HOBJECT_GET_ASIZE(obj),
	                     (long) DUK_HOBJECT_GET_HSIZE(obj),
	                     (long) new_e_size_adjusted,
	                     (long) new_a_size,
	                     (long) new_h_size,
	                     (long) abandon_array,
	                     (long) new_e_size));

	/*
	 *  Property count check.  This is the only point where we ensure that
	 *  we don't get more (allocated) property space that we can handle.
	 *  There aren't hard limits as such, but some algorithms may fail
	 *  if we get too close to the 4G property limit.
	 *
	 *  Since this works based on allocation size (not actually used size),
	 *  the limit is a bit approximate but good enough in practice.
	 */

	if (new_e_size_adjusted + new_a_size > DUK_HOBJECT_MAX_PROPERTIES) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return;);
	}
#if defined(DUK_USE_OBJSIZES16)
	if (new_e_size_adjusted > DUK_UINT16_MAX || new_a_size > DUK_UINT16_MAX) {
		/* If caller gave us sizes larger than what we can store,
		 * fail memory safely with an internal error rather than
		 * truncating the sizes.
		 */
		DUK_ERROR_INTERNAL(thr);
		DUK_WO_NORETURN(return;);
	}
#endif

	/*
	 *  Compute new alloc size and alloc new area.
	 *
	 *  The new area is not tracked in the heap at all, so it's critical
	 *  we get to free/keep it in a controlled manner.
	 */

#if defined(DUK_USE_ASSERTIONS)
	/* Whole path must be error throw free, but we may be called from
	 * within error handling so can't assert for error_not_allowed == 0.
	 */
	prev_error_not_allowed = thr->heap->error_not_allowed;
	thr->heap->error_not_allowed = 1;
#endif
	prev_ms_base_flags = thr->heap->ms_base_flags;
	thr->heap->ms_base_flags |=
	        DUK_MS_FLAG_NO_OBJECT_COMPACTION;      /* Avoid attempt to compact the current object (all objects really). */
	thr->heap->pf_prevent_count++;                 /* Avoid finalizers. */
	DUK_ASSERT(thr->heap->pf_prevent_count != 0);  /* Wrap. */

	new_alloc_size = DUK_HOBJECT_P_COMPUTE_SIZE(new_e_size_adjusted, new_a_size, new_h_size);
	DUK_DDD(DUK_DDDPRINT("new hobject allocation size is %ld", (long) new_alloc_size));
	if (new_alloc_size == 0) {
		DUK_ASSERT(new_e_size_adjusted == 0);
		DUK_ASSERT(new_a_size == 0);
		DUK_ASSERT(new_h_size == 0);
		new_p = NULL;
	} else {
		/* Alloc may trigger mark-and-sweep but no compaction, and
		 * cannot throw.
		 */
#if 0  /* XXX: inject test */
		if (1) {
			new_p = NULL;
			goto alloc_failed;
		}
#endif
		new_p = (duk_uint8_t *) DUK_ALLOC(thr->heap, new_alloc_size);
		if (new_p == NULL) {
			/* NULL always indicates alloc failure because
			 * new_alloc_size > 0.
			 */
			goto alloc_failed;
		}
	}

	/* Set up pointers to the new property area: this is hidden behind a macro
	 * because it is memory layout specific.
	 */
	DUK_HOBJECT_P_SET_REALLOC_PTRS(new_p, new_e_k, new_e_pv, new_e_f, new_a, new_h,
	                               new_e_size_adjusted, new_a_size, new_h_size);
	DUK_UNREF(new_h);  /* happens when hash part dropped */
	new_e_next = 0;

	/* if new_p == NULL, all of these pointers are NULL */
	DUK_ASSERT((new_p != NULL) ||
	           (new_e_k == NULL && new_e_pv == NULL && new_e_f == NULL &&
	            new_a == NULL && new_h == NULL));

	DUK_DDD(DUK_DDDPRINT("new alloc size %ld, new_e_k=%p, new_e_pv=%p, new_e_f=%p, new_a=%p, new_h=%p",
	                     (long) new_alloc_size, (void *) new_e_k, (void *) new_e_pv, (void *) new_e_f,
	                     (void *) new_a, (void *) new_h));

	/*
	 *  Migrate array part to start of entries if requested.
	 *
	 *  Note: from an enumeration perspective the order of entry keys matters.
	 *  Array keys should appear wherever they appeared before the array abandon
	 *  operation.  (This no longer matters much because keys are ES2015 sorted.)
	 */

	if (abandon_array) {
		/* Assuming new_a_size == 0, and that entry part contains
		 * no conflicting keys, refcounts do not need to be adjusted for
		 * the values, as they remain exactly the same.
		 *
		 * The keys, however, need to be interned, incref'd, and be
		 * reachable for GC.  Any intern attempt may trigger a GC and
		 * claim any non-reachable strings, so every key must be reachable
		 * at all times.  Refcounts must be correct to satisfy refcount
		 * assertions.
		 *
		 * A longjmp must not occur here, as the new_p allocation would
		 * leak.  Refcounts would come out correctly as the interned
		 * strings are valstack tracked.
		 */
		DUK_ASSERT(new_a_size == 0);

		DUK_STATS_INC(thr->heap, stats_object_abandon_array);

		for (i = 0; i < DUK_HOBJECT_GET_ASIZE(obj); i++) {
			duk_tval *tv1;
			duk_tval *tv2;
			duk_hstring *key;

			DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, obj) != NULL);

			tv1 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, i);
			if (DUK_TVAL_IS_UNUSED(tv1)) {
				continue;
			}

			DUK_ASSERT(new_p != NULL && new_e_k != NULL &&
			           new_e_pv != NULL && new_e_f != NULL);

			/*
			 *  Intern key via the valstack to ensure reachability behaves
			 *  properly.  We must avoid longjmp's here so use non-checked
			 *  primitives.
			 *
			 *  Note: duk_check_stack() potentially reallocs the valstack,
			 *  invalidating any duk_tval pointers to valstack.  Callers
			 *  must be careful.
			 */

#if 0  /* XXX: inject test */
			if (1) {
				goto abandon_error;
			}
#endif
			/* Never shrinks; auto-adds DUK_VALSTACK_INTERNAL_EXTRA, which
			 * is generous.
			 */
			if (!duk_check_stack(thr, 1)) {
				goto abandon_error;
			}
			DUK_ASSERT_VALSTACK_SPACE(thr, 1);
			key = duk_heap_strtable_intern_u32(thr->heap, (duk_uint32_t) i);
			if (key == NULL) {
				goto abandon_error;
			}
			duk_push_hstring(thr, key);  /* keep key reachable for GC etc; guaranteed not to fail */

			/* Key is now reachable in the valstack, don't INCREF
			 * the new allocation yet (we'll steal the refcounts
			 * from the value stack once all keys are done).
			 */

			new_e_k[new_e_next] = key;
			tv2 = &new_e_pv[new_e_next].v;  /* array entries are all plain values */
			DUK_TVAL_SET_TVAL(tv2, tv1);
			new_e_f[new_e_next] = DUK_PROPDESC_FLAG_WRITABLE |
			                      DUK_PROPDESC_FLAG_ENUMERABLE |
			                      DUK_PROPDESC_FLAG_CONFIGURABLE;
			new_e_next++;

			/* Note: new_e_next matches pushed temp key count, and nothing can
			 * fail above between the push and this point.
			 */
		}

		/* Steal refcounts from value stack. */
		DUK_DDD(DUK_DDDPRINT("abandon array: pop %ld key temps from valstack", (long) new_e_next));
		duk_pop_n_nodecref_unsafe(thr, (duk_idx_t) new_e_next);
	}

	/*
	 *  Copy keys and values in the entry part (compacting them at the same time).
	 */

	for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
		duk_hstring *key;

		DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, obj) != NULL);

		key = DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i);
		if (key == NULL) {
			continue;
		}

		DUK_ASSERT(new_p != NULL && new_e_k != NULL &&
		           new_e_pv != NULL && new_e_f != NULL);

		new_e_k[new_e_next] = key;
		new_e_pv[new_e_next] = DUK_HOBJECT_E_GET_VALUE(thr->heap, obj, i);
		new_e_f[new_e_next] = DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, i);
		new_e_next++;
	}
	/* the entries [new_e_next, new_e_size_adjusted[ are left uninitialized on purpose (ok, not gc reachable) */

	/*
	 *  Copy array elements to new array part.  If the new array part is
	 *  larger, initialize the unused entries as UNUSED because they are
	 *  GC reachable.
	 */

#if defined(DUK_USE_ASSERTIONS)
	/* Caller must have decref'd values above new_a_size (if that is necessary). */
	if (!abandon_array) {
		for (i = new_a_size; i < DUK_HOBJECT_GET_ASIZE(obj); i++) {
			duk_tval *tv;
			tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, i);
			DUK_ASSERT(DUK_TVAL_IS_UNUSED(tv));
		}
	}
#endif
	if (new_a_size > DUK_HOBJECT_GET_ASIZE(obj)) {
		array_copy_size = sizeof(duk_tval) * DUK_HOBJECT_GET_ASIZE(obj);
	} else {
		array_copy_size = sizeof(duk_tval) * new_a_size;
	}

	DUK_ASSERT(new_a != NULL || array_copy_size == 0U);
	DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, obj) != NULL || array_copy_size == 0U);
	DUK_ASSERT(DUK_HOBJECT_GET_ASIZE(obj) > 0 || array_copy_size == 0U);
	duk_memcpy_unsafe((void *) new_a,
	                  (const void *) DUK_HOBJECT_A_GET_BASE(thr->heap, obj),
	                  array_copy_size);

	for (i = DUK_HOBJECT_GET_ASIZE(obj); i < new_a_size; i++) {
		duk_tval *tv = &new_a[i];
		DUK_TVAL_SET_UNUSED(tv);
	}

	/*
	 *  Rebuild the hash part always from scratch (guaranteed to finish
	 *  as long as caller gave consistent parameters).
	 *
	 *  Any resize of hash part requires rehashing.  In addition, by rehashing
	 *  get rid of any elements marked deleted (DUK__HASH_DELETED) which is critical
	 *  to ensuring the hash part never fills up.
	 */

#if defined(DUK_USE_HOBJECT_HASH_PART)
	if (new_h_size == 0) {
		DUK_DDD(DUK_DDDPRINT("no hash part, no rehash"));
	} else {
		duk_uint32_t mask;

		DUK_ASSERT(new_h != NULL);

		/* fill new_h with u32 0xff = UNUSED */
		DUK_ASSERT(new_h_size > 0);
		duk_memset(new_h, 0xff, sizeof(duk_uint32_t) * new_h_size);

		DUK_ASSERT(new_e_next <= new_h_size);  /* equality not actually possible */

		mask = new_h_size - 1;
		for (i = 0; i < new_e_next; i++) {
			duk_hstring *key = new_e_k[i];
			duk_uint32_t j, step;

			DUK_ASSERT(key != NULL);
			j = DUK_HSTRING_GET_HASH(key) & mask;
			step = 1;  /* Cache friendly but clustering prone. */

			for (;;) {
				DUK_ASSERT(new_h[j] != DUK__HASH_DELETED);  /* should never happen */
				if (new_h[j] == DUK__HASH_UNUSED) {
					DUK_DDD(DUK_DDDPRINT("rebuild hit %ld -> %ld", (long) j, (long) i));
					new_h[j] = (duk_uint32_t) i;
					break;
				}
				DUK_DDD(DUK_DDDPRINT("rebuild miss %ld, step %ld", (long) j, (long) step));
				j = (j + step) & mask;

				/* Guaranteed to finish (hash is larger than #props). */
			}
		}
	}
#endif  /* DUK_USE_HOBJECT_HASH_PART */

	/*
	 *  Nice debug log.
	 */

	DUK_DD(DUK_DDPRINT("resized hobject %p props (%ld -> %ld bytes), from {p=%p,e_size=%ld,e_next=%ld,a_size=%ld,h_size=%ld} to "
	                   "{p=%p,e_size=%ld,e_next=%ld,a_size=%ld,h_size=%ld}, abandon_array=%ld, unadjusted new_e_size=%ld",
	                   (void *) obj,
	                   (long) DUK_HOBJECT_P_COMPUTE_SIZE(DUK_HOBJECT_GET_ESIZE(obj),
	                                                     DUK_HOBJECT_GET_ASIZE(obj),
	                                                     DUK_HOBJECT_GET_HSIZE(obj)),
	                   (long) new_alloc_size,
	                   (void *) DUK_HOBJECT_GET_PROPS(thr->heap, obj),
	                   (long) DUK_HOBJECT_GET_ESIZE(obj),
	                   (long) DUK_HOBJECT_GET_ENEXT(obj),
	                   (long) DUK_HOBJECT_GET_ASIZE(obj),
	                   (long) DUK_HOBJECT_GET_HSIZE(obj),
	                   (void *) new_p,
	                   (long) new_e_size_adjusted,
	                   (long) new_e_next,
	                   (long) new_a_size,
	                   (long) new_h_size,
	                   (long) abandon_array,
	                   (long) new_e_size));

	/*
	 *  All done, switch properties ('p') allocation to new one.
	 */

	DUK_FREE_CHECKED(thr, DUK_HOBJECT_GET_PROPS(thr->heap, obj));  /* NULL obj->p is OK */
	DUK_HOBJECT_SET_PROPS(thr->heap, obj, new_p);
	DUK_HOBJECT_SET_ESIZE(obj, new_e_size_adjusted);
	DUK_HOBJECT_SET_ENEXT(obj, new_e_next);
	DUK_HOBJECT_SET_ASIZE(obj, new_a_size);
	DUK_HOBJECT_SET_HSIZE(obj, new_h_size);

	/* Clear array part flag only after switching. */
	if (abandon_array) {
		DUK_HOBJECT_CLEAR_ARRAY_PART(obj);
	}

	DUK_DDD(DUK_DDDPRINT("resize result: %!O", (duk_heaphdr *) obj));

	DUK_ASSERT(thr->heap->pf_prevent_count > 0);
	thr->heap->pf_prevent_count--;
	thr->heap->ms_base_flags = prev_ms_base_flags;
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(thr->heap->error_not_allowed == 1);
	thr->heap->error_not_allowed = prev_error_not_allowed;
#endif

	/*
	 *  Post resize assertions.
	 */

#if defined(DUK_USE_ASSERTIONS)
	/* XXX: post-checks (such as no duplicate keys) */
#endif
	return;

	/*
	 *  Abandon array failed.  We don't need to DECREF anything
	 *  because the references in the new allocation are not
	 *  INCREF'd until abandon is complete.  The string interned
	 *  keys are on the value stack and are handled normally by
	 *  unwind.
	 */

 abandon_error:
 alloc_failed:
	DUK_D(DUK_DPRINT("object property table resize failed"));

	DUK_FREE_CHECKED(thr, new_p);  /* OK for NULL. */

	thr->heap->pf_prevent_count--;
	thr->heap->ms_base_flags = prev_ms_base_flags;
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(thr->heap->error_not_allowed == 1);
	thr->heap->error_not_allowed = prev_error_not_allowed;
#endif

	DUK_ERROR_ALLOC_FAILED(thr);
	DUK_WO_NORETURN(return;);
}

/*
 *  Helpers to resize properties allocation on specific needs.
 */

DUK_INTERNAL void duk_hobject_resize_entrypart(duk_hthread *thr,
                                               duk_hobject *obj,
                                               duk_uint32_t new_e_size) {
	duk_uint32_t old_e_size;
	duk_uint32_t new_a_size;
	duk_uint32_t new_h_size;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);

	old_e_size = DUK_HOBJECT_GET_ESIZE(obj);
	if (old_e_size > new_e_size) {
		new_e_size = old_e_size;
	}
#if defined(DUK_USE_HOBJECT_HASH_PART)
	new_h_size = duk__get_default_h_size(new_e_size);
#else
	new_h_size = 0;
#endif
	new_a_size = DUK_HOBJECT_GET_ASIZE(obj);

	duk_hobject_realloc_props(thr, obj, new_e_size, new_a_size, new_h_size, 0);
}

/* Grow entry part allocation for one additional entry. */
DUK_LOCAL void duk__grow_props_for_new_entry_item(duk_hthread *thr, duk_hobject *obj) {
	duk_uint32_t old_e_used;  /* actually used, non-NULL entries */
	duk_uint32_t new_e_size_minimum;
	duk_uint32_t new_e_size;
	duk_uint32_t new_a_size;
	duk_uint32_t new_h_size;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);

	/* Duktape 0.11.0 and prior tried to optimize the resize by not
	 * counting the number of actually used keys prior to the resize.
	 * This worked mostly well but also caused weird leak-like behavior
	 * as in: test-bug-object-prop-alloc-unbounded.js.  So, now we count
	 * the keys explicitly to compute the new entry part size.
	 */

	old_e_used = duk__count_used_e_keys(thr, obj);
	new_e_size_minimum = old_e_used + 1;
	new_e_size = old_e_used + duk__get_min_grow_e(old_e_used);
#if defined(DUK_USE_HOBJECT_HASH_PART)
	new_h_size = duk__get_default_h_size(new_e_size);
#else
	new_h_size = 0;
#endif
	new_a_size = DUK_HOBJECT_GET_ASIZE(obj);

#if defined(DUK_USE_OBJSIZES16)
	if (new_e_size > DUK_UINT16_MAX) {
		new_e_size = DUK_UINT16_MAX;
	}
	if (new_h_size > DUK_UINT16_MAX) {
		new_h_size = DUK_UINT16_MAX;
	}
	if (new_a_size > DUK_UINT16_MAX) {
		new_a_size = DUK_UINT16_MAX;
	}
#endif
	DUK_ASSERT(new_h_size == 0 || new_h_size >= new_e_size);

	if (!(new_e_size >= new_e_size_minimum)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return;);
	}

	duk_hobject_realloc_props(thr, obj, new_e_size, new_a_size, new_h_size, 0);
}

/* Grow array part for a new highest array index. */
DUK_LOCAL void duk__grow_props_for_array_item(duk_hthread *thr, duk_hobject *obj, duk_uint32_t highest_arr_idx) {
	duk_uint32_t new_e_size;
	duk_uint32_t new_a_size;
	duk_uint32_t new_a_size_minimum;
	duk_uint32_t new_h_size;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(highest_arr_idx >= DUK_HOBJECT_GET_ASIZE(obj));

	new_e_size = DUK_HOBJECT_GET_ESIZE(obj);
	new_h_size = DUK_HOBJECT_GET_HSIZE(obj);
	new_a_size_minimum = highest_arr_idx + 1;
	new_a_size = highest_arr_idx + duk__get_min_grow_a(highest_arr_idx);
	DUK_ASSERT(new_a_size >= highest_arr_idx + 1);  /* duk__get_min_grow_a() is always >= 1 */

#if defined(DUK_USE_OBJSIZES16)
	if (new_e_size > DUK_UINT16_MAX) {
		new_e_size = DUK_UINT16_MAX;
	}
	if (new_h_size > DUK_UINT16_MAX) {
		new_h_size = DUK_UINT16_MAX;
	}
	if (new_a_size > DUK_UINT16_MAX) {
		new_a_size = DUK_UINT16_MAX;
	}
#endif

	if (!(new_a_size >= new_a_size_minimum)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return;);
	}

	duk_hobject_realloc_props(thr, obj, new_e_size, new_a_size, new_h_size, 0);
}

/* Abandon array part, moving array entries into entries part.
 * This requires a props resize, which is a heavy operation.
 * We also compact the entries part while we're at it, although
 * this is not strictly required.
 */
DUK_LOCAL void duk__abandon_array_part(duk_hthread *thr, duk_hobject *obj) {
	duk_uint32_t new_e_size_minimum;
	duk_uint32_t new_e_size;
	duk_uint32_t new_a_size;
	duk_uint32_t new_h_size;
	duk_uint32_t e_used;  /* actually used, non-NULL keys */
	duk_uint32_t a_used;
	duk_uint32_t a_size;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);

	e_used = duk__count_used_e_keys(thr, obj);
	duk__compute_a_stats(thr, obj, &a_used, &a_size);

	/*
	 *  Must guarantee all actually used array entries will fit into
	 *  new entry part.  Add one growth step to ensure we don't run out
	 *  of space right away.
	 */

	new_e_size_minimum = e_used + a_used;
	new_e_size = new_e_size_minimum + duk__get_min_grow_e(new_e_size_minimum);
	new_a_size = 0;
#if defined(DUK_USE_HOBJECT_HASH_PART)
	new_h_size = duk__get_default_h_size(new_e_size);
#else
	new_h_size = 0;
#endif

#if defined(DUK_USE_OBJSIZES16)
	if (new_e_size > DUK_UINT16_MAX) {
		new_e_size = DUK_UINT16_MAX;
	}
	if (new_h_size > DUK_UINT16_MAX) {
		new_h_size = DUK_UINT16_MAX;
	}
	if (new_a_size > DUK_UINT16_MAX) {
		new_a_size = DUK_UINT16_MAX;
	}
#endif

	if (!(new_e_size >= new_e_size_minimum)) {
		DUK_ERROR_ALLOC_FAILED(thr);
		DUK_WO_NORETURN(return;);
	}

	DUK_DD(DUK_DDPRINT("abandon array part for hobject %p, "
	                   "array stats before: e_used=%ld, a_used=%ld, a_size=%ld; "
	                   "resize to e_size=%ld, a_size=%ld, h_size=%ld",
	                   (void *) obj, (long) e_used, (long) a_used, (long) a_size,
	                   (long) new_e_size, (long) new_a_size, (long) new_h_size));

	duk_hobject_realloc_props(thr, obj, new_e_size, new_a_size, new_h_size, 1);
}

/*
 *  Compact an object.  Minimizes allocation size for objects which are
 *  not likely to be extended.  This is useful for internal and non-
 *  extensible objects, but can also be called for non-extensible objects.
 *  May abandon the array part if it is computed to be too sparse.
 *
 *  This call is relatively expensive, as it needs to scan both the
 *  entries and the array part.
 *
 *  The call may fail due to allocation error.
 */

DUK_INTERNAL void duk_hobject_compact_props(duk_hthread *thr, duk_hobject *obj) {
	duk_uint32_t e_size;       /* currently used -> new size */
	duk_uint32_t a_size;       /* currently required */
	duk_uint32_t a_used;       /* actually used */
	duk_uint32_t h_size;
	duk_bool_t abandon_array;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_DD(DUK_DDPRINT("ignore attempt to compact a rom object"));
		return;
	}
#endif

	e_size = duk__count_used_e_keys(thr, obj);
	duk__compute_a_stats(thr, obj, &a_used, &a_size);

	DUK_DD(DUK_DDPRINT("compacting hobject, used e keys %ld, used a keys %ld, min a size %ld, "
	                   "resized array density would be: %ld/%ld = %lf",
	                   (long) e_size, (long) a_used, (long) a_size,
	                   (long) a_used, (long) a_size,
	                   (double) a_used / (double) a_size));

	if (duk__abandon_array_density_check(a_used, a_size)) {
		DUK_DD(DUK_DDPRINT("decided to abandon array during compaction, a_used=%ld, a_size=%ld",
		                   (long) a_used, (long) a_size));
		abandon_array = 1;
		e_size += a_used;
		a_size = 0;
	} else {
		DUK_DD(DUK_DDPRINT("decided to keep array during compaction"));
		abandon_array = 0;
	}

#if defined(DUK_USE_HOBJECT_HASH_PART)
	if (e_size >= DUK_USE_HOBJECT_HASH_PROP_LIMIT) {
		h_size = duk__get_default_h_size(e_size);
	} else {
		h_size = 0;
	}
#else
	h_size = 0;
#endif

	DUK_DD(DUK_DDPRINT("compacting hobject -> new e_size %ld, new a_size=%ld, new h_size=%ld, abandon_array=%ld",
	                   (long) e_size, (long) a_size, (long) h_size, (long) abandon_array));

	duk_hobject_realloc_props(thr, obj, e_size, a_size, h_size, abandon_array);
}

/*
 *  Find an existing key from entry part either by linear scan or by
 *  using the hash index (if it exists).
 *
 *  Sets entry index (and possibly the hash index) to output variables,
 *  which allows the caller to update the entry and hash entries in-place.
 *  If entry is not found, both values are set to -1.  If entry is found
 *  but there is no hash part, h_idx is set to -1.
 */

DUK_INTERNAL duk_bool_t duk_hobject_find_entry(duk_heap *heap, duk_hobject *obj, duk_hstring *key, duk_int_t *e_idx, duk_int_t *h_idx) {
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(e_idx != NULL);
	DUK_ASSERT(h_idx != NULL);
	DUK_UNREF(heap);

	if (DUK_LIKELY(DUK_HOBJECT_GET_HSIZE(obj) == 0))
	{
		/* Linear scan: more likely because most objects are small.
		 * This is an important fast path.
		 *
		 * XXX: this might be worth inlining for property lookups.
		 */
		duk_uint_fast32_t i;
		duk_uint_fast32_t n;
		duk_hstring **h_keys_base;
		DUK_DDD(DUK_DDDPRINT("duk_hobject_find_entry() using linear scan for lookup"));

		h_keys_base = DUK_HOBJECT_E_GET_KEY_BASE(heap, obj);
		n = DUK_HOBJECT_GET_ENEXT(obj);
		for (i = 0; i < n; i++) {
			if (h_keys_base[i] == key) {
				*e_idx = (duk_int_t) i;
				*h_idx = -1;
				return 1;
			}
		}
	}
#if defined(DUK_USE_HOBJECT_HASH_PART)
	else
	{
		/* hash lookup */
		duk_uint32_t n;
		duk_uint32_t i, step;
		duk_uint32_t *h_base;
		duk_uint32_t mask;

		DUK_DDD(DUK_DDDPRINT("duk_hobject_find_entry() using hash part for lookup"));

		h_base = DUK_HOBJECT_H_GET_BASE(heap, obj);
		n = DUK_HOBJECT_GET_HSIZE(obj);
		mask = n - 1;
		i = DUK_HSTRING_GET_HASH(key) & mask;
		step = 1;  /* Cache friendly but clustering prone. */

		for (;;) {
			duk_uint32_t t;

			DUK_ASSERT_DISABLE(i >= 0);  /* unsigned */
			DUK_ASSERT(i < DUK_HOBJECT_GET_HSIZE(obj));
			t = h_base[i];
			DUK_ASSERT(t == DUK__HASH_UNUSED || t == DUK__HASH_DELETED ||
			           (t < DUK_HOBJECT_GET_ESIZE(obj)));  /* t >= 0 always true, unsigned */

			if (t == DUK__HASH_UNUSED) {
				break;
			} else if (t == DUK__HASH_DELETED) {
				DUK_DDD(DUK_DDDPRINT("lookup miss (deleted) i=%ld, t=%ld",
				                     (long) i, (long) t));
			} else {
				DUK_ASSERT(t < DUK_HOBJECT_GET_ESIZE(obj));
				if (DUK_HOBJECT_E_GET_KEY(heap, obj, t) == key) {
					DUK_DDD(DUK_DDDPRINT("lookup hit i=%ld, t=%ld -> key %p",
					                     (long) i, (long) t, (void *) key));
					*e_idx = (duk_int_t) t;
					*h_idx = (duk_int_t) i;
					return 1;
				}
				DUK_DDD(DUK_DDDPRINT("lookup miss i=%ld, t=%ld",
				                     (long) i, (long) t));
			}
			i = (i + step) & mask;

			/* Guaranteed to finish (hash is larger than #props). */
		}
	}
#endif  /* DUK_USE_HOBJECT_HASH_PART */

	/* Not found, leave e_idx and h_idx unset. */
	return 0;
}

/* For internal use: get non-accessor entry value */
DUK_INTERNAL duk_tval *duk_hobject_find_entry_tval_ptr(duk_heap *heap, duk_hobject *obj, duk_hstring *key) {
	duk_int_t e_idx;
	duk_int_t h_idx;

	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_UNREF(heap);

	if (duk_hobject_find_entry(heap, obj, key, &e_idx, &h_idx)) {
		DUK_ASSERT(e_idx >= 0);
		if (!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(heap, obj, e_idx)) {
			return DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(heap, obj, e_idx);
		}
	}
	return NULL;
}

DUK_INTERNAL duk_tval *duk_hobject_find_entry_tval_ptr_stridx(duk_heap *heap, duk_hobject *obj, duk_small_uint_t stridx) {
	return duk_hobject_find_entry_tval_ptr(heap, obj, DUK_HEAP_GET_STRING(heap, stridx));
}

/* For internal use: get non-accessor entry value and attributes */
DUK_INTERNAL duk_tval *duk_hobject_find_entry_tval_ptr_and_attrs(duk_heap *heap, duk_hobject *obj, duk_hstring *key, duk_uint_t *out_attrs) {
	duk_int_t e_idx;
	duk_int_t h_idx;

	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(out_attrs != NULL);
	DUK_UNREF(heap);

	if (duk_hobject_find_entry(heap, obj, key, &e_idx, &h_idx)) {
		DUK_ASSERT(e_idx >= 0);
		if (!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(heap, obj, e_idx)) {
			*out_attrs = DUK_HOBJECT_E_GET_FLAGS(heap, obj, e_idx);
			return DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(heap, obj, e_idx);
		}
	}
	/* If not found, out_attrs is left unset. */
	return NULL;
}

/* For internal use: get array part value */
DUK_INTERNAL duk_tval *duk_hobject_find_array_entry_tval_ptr(duk_heap *heap, duk_hobject *obj, duk_uarridx_t i) {
	duk_tval *tv;

	DUK_ASSERT(obj != NULL);
	DUK_UNREF(heap);

	if (!DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
		return NULL;
	}
	if (i >= DUK_HOBJECT_GET_ASIZE(obj)) {
		return NULL;
	}
	tv = DUK_HOBJECT_A_GET_VALUE_PTR(heap, obj, i);
	return tv;
}

/*
 *  Allocate and initialize a new entry, resizing the properties allocation
 *  if necessary.  Returns entry index (e_idx) or throws an error if alloc fails.
 *
 *  Sets the key of the entry (increasing the key's refcount), and updates
 *  the hash part if it exists.  Caller must set value and flags, and update
 *  the entry value refcount.  A decref for the previous value is not necessary.
 */

DUK_LOCAL duk_int_t duk__hobject_alloc_entry_checked(duk_hthread *thr, duk_hobject *obj, duk_hstring *key) {
	duk_uint32_t idx;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(obj) <= DUK_HOBJECT_GET_ESIZE(obj));

#if defined(DUK_USE_ASSERTIONS)
	/* key must not already exist in entry part */
	{
		duk_uint_fast32_t i;
		for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
			DUK_ASSERT(DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i) != key);
		}
	}
#endif

	if (DUK_HOBJECT_GET_ENEXT(obj) >= DUK_HOBJECT_GET_ESIZE(obj)) {
		/* only need to guarantee 1 more slot, but allocation growth is in chunks */
		DUK_DDD(DUK_DDDPRINT("entry part full, allocate space for one more entry"));
		duk__grow_props_for_new_entry_item(thr, obj);
	}
	DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(obj) < DUK_HOBJECT_GET_ESIZE(obj));
	idx = DUK_HOBJECT_POSTINC_ENEXT(obj);

	/* previous value is assumed to be garbage, so don't touch it */
	DUK_HOBJECT_E_SET_KEY(thr->heap, obj, idx, key);
	DUK_HSTRING_INCREF(thr, key);

#if defined(DUK_USE_HOBJECT_HASH_PART)
	if (DUK_UNLIKELY(DUK_HOBJECT_GET_HSIZE(obj) > 0)) {
		duk_uint32_t n, mask;
		duk_uint32_t i, step;
		duk_uint32_t *h_base = DUK_HOBJECT_H_GET_BASE(thr->heap, obj);

		n = DUK_HOBJECT_GET_HSIZE(obj);
		mask = n - 1;
		i = DUK_HSTRING_GET_HASH(key) & mask;
		step = 1;  /* Cache friendly but clustering prone. */

		for (;;) {
			duk_uint32_t t = h_base[i];
			if (t == DUK__HASH_UNUSED || t == DUK__HASH_DELETED) {
				DUK_DDD(DUK_DDDPRINT("duk__hobject_alloc_entry_checked() inserted key into hash part, %ld -> %ld",
				                     (long) i, (long) idx));
				DUK_ASSERT_DISABLE(i >= 0);  /* unsigned */
				DUK_ASSERT(i < DUK_HOBJECT_GET_HSIZE(obj));
				DUK_ASSERT_DISABLE(idx >= 0);
				DUK_ASSERT(idx < DUK_HOBJECT_GET_ESIZE(obj));
				h_base[i] = idx;
				break;
			}
			DUK_DDD(DUK_DDDPRINT("duk__hobject_alloc_entry_checked() miss %ld", (long) i));
			i = (i + step) & mask;

			/* Guaranteed to finish (hash is larger than #props). */
		}
	}
#endif  /* DUK_USE_HOBJECT_HASH_PART */

	/* Note: we could return the hash index here too, but it's not
	 * needed right now.
	 */

	DUK_ASSERT_DISABLE(idx >= 0);
	DUK_ASSERT(idx < DUK_HOBJECT_GET_ESIZE(obj));
	DUK_ASSERT(idx < DUK_HOBJECT_GET_ENEXT(obj));
	return (duk_int_t) idx;
}

/*
 *  Object internal value
 *
 *  Returned value is guaranteed to be reachable / incref'd, caller does not need
 *  to incref OR decref.  No proxies or accessors are invoked, no prototype walk.
 */

DUK_INTERNAL duk_tval *duk_hobject_get_internal_value_tval_ptr(duk_heap *heap, duk_hobject *obj) {
	return duk_hobject_find_entry_tval_ptr_stridx(heap, obj, DUK_STRIDX_INT_VALUE);
}

DUK_LOCAL duk_heaphdr *duk_hobject_get_internal_value_heaphdr(duk_heap *heap, duk_hobject *obj) {
	duk_tval *tv;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(obj != NULL);

	tv = duk_hobject_get_internal_value_tval_ptr(heap, obj);
	if (tv != NULL) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		return h;
	}

	return NULL;
}

DUK_INTERNAL duk_hstring *duk_hobject_get_internal_value_string(duk_heap *heap, duk_hobject *obj) {
	duk_hstring *h;

	h = (duk_hstring *) duk_hobject_get_internal_value_heaphdr(heap, obj);
	if (h != NULL) {
		DUK_ASSERT(DUK_HEAPHDR_IS_STRING((duk_heaphdr *) h));
	}
	return h;
}

DUK_LOCAL duk_hobject *duk__hobject_get_entry_object_stridx(duk_heap *heap, duk_hobject *obj, duk_small_uint_t stridx) {
	duk_tval *tv;
	duk_hobject *h;

	tv = duk_hobject_find_entry_tval_ptr_stridx(heap, obj, stridx);
	if (tv != NULL && DUK_TVAL_IS_OBJECT(tv)) {
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		return h;
	}
	return NULL;
}

DUK_INTERNAL duk_harray *duk_hobject_get_formals(duk_hthread *thr, duk_hobject *obj) {
	duk_harray *h;

	h = (duk_harray *) duk__hobject_get_entry_object_stridx(thr->heap, obj, DUK_STRIDX_INT_FORMALS);
	if (h != NULL) {
		DUK_ASSERT(DUK_HOBJECT_IS_ARRAY((duk_hobject *) h));
		DUK_ASSERT(h->length <= DUK_HOBJECT_GET_ASIZE((duk_hobject *) h));
	}
	return h;
}

DUK_INTERNAL duk_hobject *duk_hobject_get_varmap(duk_hthread *thr, duk_hobject *obj) {
	duk_hobject *h;

	h = duk__hobject_get_entry_object_stridx(thr->heap, obj, DUK_STRIDX_INT_VARMAP);
	return h;
}

/*
 *  Arguments handling helpers (argument map mainly).
 *
 *  An arguments object has exotic behavior for some numeric indices.
 *  Accesses may translate to identifier operations which may have
 *  arbitrary side effects (potentially invalidating any duk_tval
 *  pointers).
 */

/* Lookup 'key' from arguments internal 'map', perform a variable lookup
 * if mapped, and leave the result on top of stack (and return non-zero).
 * Used in E5 Section 10.6 algorithms [[Get]] and [[GetOwnProperty]].
 */
DUK_LOCAL
duk_bool_t duk__lookup_arguments_map(duk_hthread *thr,
                                     duk_hobject *obj,
                                     duk_hstring *key,
                                     duk_propdesc *temp_desc,
                                     duk_hobject **out_map,
                                     duk_hobject **out_varenv) {
	duk_hobject *map;
	duk_hobject *varenv;
	duk_bool_t rc;

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_DDD(DUK_DDDPRINT("arguments map lookup: thr=%p, obj=%p, key=%p, temp_desc=%p "
	                     "(obj -> %!O, key -> %!O)",
	                     (void *) thr, (void *) obj, (void *) key, (void *) temp_desc,
	                     (duk_heaphdr *) obj, (duk_heaphdr *) key));

	if (!duk_hobject_get_own_propdesc(thr, obj, DUK_HTHREAD_STRING_INT_MAP(thr), temp_desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
		DUK_DDD(DUK_DDDPRINT("-> no 'map'"));
		return 0;
	}

	map = duk_require_hobject(thr, -1);
	DUK_ASSERT(map != NULL);
	duk_pop_unsafe(thr);  /* map is reachable through obj */

	if (!duk_hobject_get_own_propdesc(thr, map, key, temp_desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
		DUK_DDD(DUK_DDDPRINT("-> 'map' exists, but key not in map"));
		return 0;
	}

	/* [... varname] */
	DUK_DDD(DUK_DDDPRINT("-> 'map' exists, and contains key, key is mapped to argument/variable binding %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));
	DUK_ASSERT(duk_is_string(thr, -1));  /* guaranteed when building arguments */

	/* get varenv for varname (callee's declarative lexical environment) */
	rc = duk_hobject_get_own_propdesc(thr, obj, DUK_HTHREAD_STRING_INT_VARENV(thr), temp_desc, DUK_GETDESC_FLAG_PUSH_VALUE);
	DUK_UNREF(rc);
	DUK_ASSERT(rc != 0);  /* arguments MUST have an initialized lexical environment reference */
	varenv = duk_require_hobject(thr, -1);
	DUK_ASSERT(varenv != NULL);
	duk_pop_unsafe(thr);  /* varenv remains reachable through 'obj' */

	DUK_DDD(DUK_DDDPRINT("arguments varenv is: %!dO", (duk_heaphdr *) varenv));

	/* success: leave varname in stack */
	*out_map = map;
	*out_varenv = varenv;
	return 1;  /* [... varname] */
}

/* Lookup 'key' from arguments internal 'map', and leave replacement value
 * on stack top if mapped (and return non-zero).
 * Used in E5 Section 10.6 algorithm for [[GetOwnProperty]] (used by [[Get]]).
 */
DUK_LOCAL duk_bool_t duk__check_arguments_map_for_get(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc) {
	duk_hobject *map;
	duk_hobject *varenv;
	duk_hstring *varname;

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	if (!duk__lookup_arguments_map(thr, obj, key, temp_desc, &map, &varenv)) {
		DUK_DDD(DUK_DDDPRINT("arguments: key not mapped, no exotic get behavior"));
		return 0;
	}

	/* [... varname] */

	varname = duk_require_hstring(thr, -1);
	DUK_ASSERT(varname != NULL);
	duk_pop_unsafe(thr);  /* varname is still reachable */

	DUK_DDD(DUK_DDDPRINT("arguments object automatic getvar for a bound variable; "
	                     "key=%!O, varname=%!O",
	                     (duk_heaphdr *) key,
	                     (duk_heaphdr *) varname));

	(void) duk_js_getvar_envrec(thr, varenv, varname, 1 /*throw*/);

	/* [... value this_binding] */

	duk_pop_unsafe(thr);

	/* leave result on stack top */
	return 1;
}

/* Lookup 'key' from arguments internal 'map', perform a variable write if mapped.
 * Used in E5 Section 10.6 algorithm for [[DefineOwnProperty]] (used by [[Put]]).
 * Assumes stack top contains 'put' value (which is NOT popped).
 */
DUK_LOCAL void duk__check_arguments_map_for_put(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc, duk_bool_t throw_flag) {
	duk_hobject *map;
	duk_hobject *varenv;
	duk_hstring *varname;

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	if (!duk__lookup_arguments_map(thr, obj, key, temp_desc, &map, &varenv)) {
		DUK_DDD(DUK_DDDPRINT("arguments: key not mapped, no exotic put behavior"));
		return;
	}

	/* [... put_value varname] */

	varname = duk_require_hstring(thr, -1);
	DUK_ASSERT(varname != NULL);
	duk_pop_unsafe(thr);  /* varname is still reachable */

	DUK_DDD(DUK_DDDPRINT("arguments object automatic putvar for a bound variable; "
	                     "key=%!O, varname=%!O, value=%!T",
	                     (duk_heaphdr *) key,
	                     (duk_heaphdr *) varname,
	                     (duk_tval *) duk_require_tval(thr, -1)));

	/* [... put_value] */

	/*
	 *  Note: although arguments object variable mappings are only established
	 *  for non-strict functions (and a call to a non-strict function created
	 *  the arguments object in question), an inner strict function may be doing
	 *  the actual property write.  Hence the throw_flag applied here comes from
	 *  the property write call.
	 */

	duk_js_putvar_envrec(thr, varenv, varname, duk_require_tval(thr, -1), throw_flag);

	/* [... put_value] */
}

/* Lookup 'key' from arguments internal 'map', delete mapping if found.
 * Used in E5 Section 10.6 algorithm for [[Delete]].  Note that the
 * variable/argument itself (where the map points) is not deleted.
 */
DUK_LOCAL void duk__check_arguments_map_for_delete(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *temp_desc) {
	duk_hobject *map;

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	if (!duk_hobject_get_own_propdesc(thr, obj, DUK_HTHREAD_STRING_INT_MAP(thr), temp_desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
		DUK_DDD(DUK_DDDPRINT("arguments: key not mapped, no exotic delete behavior"));
		return;
	}

	map = duk_require_hobject(thr, -1);
	DUK_ASSERT(map != NULL);
	duk_pop_unsafe(thr);  /* map is reachable through obj */

	DUK_DDD(DUK_DDDPRINT("-> have 'map', delete key %!O from map (if exists)); ignore result",
	                     (duk_heaphdr *) key));

	/* Note: no recursion issue, we can trust 'map' to behave */
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_BEHAVIOR(map));
	DUK_DDD(DUK_DDDPRINT("map before deletion: %!O", (duk_heaphdr *) map));
	(void) duk_hobject_delprop_raw(thr, map, key, 0);  /* ignore result */
	DUK_DDD(DUK_DDDPRINT("map after deletion: %!O", (duk_heaphdr *) map));
}

/*
 *  ECMAScript compliant [[GetOwnProperty]](P), for internal use only.
 *
 *  If property is found:
 *    - Fills descriptor fields to 'out_desc'
 *    - If DUK_GETDESC_FLAG_PUSH_VALUE is set, pushes a value related to the
 *      property onto the stack ('undefined' for accessor properties).
 *    - Returns non-zero
 *
 *  If property is not found:
 *    - 'out_desc' is left in untouched state (possibly garbage)
 *    - Nothing is pushed onto the stack (not even with DUK_GETDESC_FLAG_PUSH_VALUE
 *      set)
 *    - Returns zero
 *
 *  Notes:
 *
 *    - Getting a property descriptor may cause an allocation (and hence
 *      GC) to take place, hence reachability and refcount of all related
 *      values matter.  Reallocation of value stack, properties, etc may
 *      invalidate many duk_tval pointers (concretely, those which reside
 *      in memory areas subject to reallocation).  However, heap object
 *      pointers are never affected (heap objects have stable pointers).
 *
 *    - The value of a plain property is always reachable and has a non-zero
 *      reference count.
 *
 *    - The value of a virtual property is not necessarily reachable from
 *      elsewhere and may have a refcount of zero.  Hence we push it onto
 *      the valstack for the caller, which ensures it remains reachable
 *      while it is needed.
 *
 *    - There are no virtual accessor properties.  Hence, all getters and
 *      setters are always related to concretely stored properties, which
 *      ensures that the get/set functions in the resulting descriptor are
 *      reachable and have non-zero refcounts.  Should there be virtual
 *      accessor properties later, this would need to change.
 */

DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_uint32_t arr_idx, duk_propdesc *out_desc, duk_small_uint_t flags) {
	duk_tval *tv;

	DUK_DDD(DUK_DDDPRINT("duk_hobject_get_own_propdesc: thr=%p, obj=%p, key=%p, out_desc=%p, flags=%lx, "
	                     "arr_idx=%ld (obj -> %!O, key -> %!O)",
	                     (void *) thr, (void *) obj, (void *) key, (void *) out_desc,
	                     (long) flags, (long) arr_idx,
	                     (duk_heaphdr *) obj, (duk_heaphdr *) key));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(out_desc != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_STATS_INC(thr->heap, stats_getownpropdesc_count);

	/* Each code path returning 1 (= found) must fill in all the output
	 * descriptor fields.  We don't do it beforehand because it'd be
	 * unnecessary work if the property isn't found and would happen
	 * multiple times for an inheritance chain.
	 */
	DUK_ASSERT_SET_GARBAGE(out_desc, sizeof(*out_desc));
#if 0
	out_desc->flags = 0;
	out_desc->get = NULL;
	out_desc->set = NULL;
	out_desc->e_idx = -1;
	out_desc->h_idx = -1;
	out_desc->a_idx = -1;
#endif

	/*
	 *  Try entries part first because it's the common case.
	 *
	 *  Array part lookups are usually handled by the array fast path, and
	 *  are not usually inherited.  Array and entry parts never contain the
	 *  same keys so the entry part vs. array part order doesn't matter.
	 */

	if (duk_hobject_find_entry(thr->heap, obj, key, &out_desc->e_idx, &out_desc->h_idx)) {
		duk_int_t e_idx = out_desc->e_idx;
		DUK_ASSERT(out_desc->e_idx >= 0);
		out_desc->a_idx = -1;
		out_desc->flags = DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, e_idx);
		out_desc->get = NULL;
		out_desc->set = NULL;
		if (DUK_UNLIKELY(out_desc->flags & DUK_PROPDESC_FLAG_ACCESSOR)) {
			DUK_DDD(DUK_DDDPRINT("-> found accessor property in entry part"));
			out_desc->get = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, obj, e_idx);
			out_desc->set = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, obj, e_idx);
			if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
				/* a dummy undefined value is pushed to make valstack
				 * behavior uniform for caller
				 */
				duk_push_undefined(thr);
			}
		} else {
			DUK_DDD(DUK_DDDPRINT("-> found plain property in entry part"));
			tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, e_idx);
			if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
				duk_push_tval(thr, tv);
			}
		}
		goto prop_found;
	}

	/*
	 *  Try array part.
	 */

	if (DUK_HOBJECT_HAS_ARRAY_PART(obj) && arr_idx != DUK__NO_ARRAY_INDEX) {
		if (arr_idx < DUK_HOBJECT_GET_ASIZE(obj)) {
			tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
			if (!DUK_TVAL_IS_UNUSED(tv)) {
				DUK_DDD(DUK_DDDPRINT("-> found in array part"));
				if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
					duk_push_tval(thr, tv);
				}
				/* implicit attributes */
				out_desc->flags = DUK_PROPDESC_FLAG_WRITABLE |
				                  DUK_PROPDESC_FLAG_CONFIGURABLE |
				                  DUK_PROPDESC_FLAG_ENUMERABLE;
				out_desc->get = NULL;
				out_desc->set = NULL;
				out_desc->e_idx = -1;
				out_desc->h_idx = -1;
				out_desc->a_idx = (duk_int_t) arr_idx;  /* XXX: limit 2G due to being signed */
				goto prop_found;
			}
		}
	}

	DUK_DDD(DUK_DDDPRINT("-> not found as a concrete property"));

	/*
	 *  Not found as a concrete property, check for virtual properties.
	 */

	if (!DUK_HOBJECT_HAS_VIRTUAL_PROPERTIES(obj)) {
		/* Quick skip. */
		goto prop_not_found;
	}

	if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
		duk_harray *a;

		DUK_DDD(DUK_DDDPRINT("array object exotic property get for key: %!O, arr_idx: %ld",
		                     (duk_heaphdr *) key, (long) arr_idx));

		a = (duk_harray *) obj;
		DUK_HARRAY_ASSERT_VALID(a);

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			DUK_DDD(DUK_DDDPRINT("-> found, key is 'length', length exotic behavior"));

			if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
				duk_push_uint(thr, (duk_uint_t) a->length);
			}
			out_desc->flags = DUK_PROPDESC_FLAG_VIRTUAL;
			if (DUK_HARRAY_LENGTH_WRITABLE(a)) {
				out_desc->flags |= DUK_PROPDESC_FLAG_WRITABLE;
			}
			out_desc->get = NULL;
			out_desc->set = NULL;
			out_desc->e_idx = -1;
			out_desc->h_idx = -1;
			out_desc->a_idx = -1;

			DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj));
			goto prop_found_noexotic;  /* cannot be arguments exotic */
		}
	} else if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(obj)) {
		DUK_DDD(DUK_DDDPRINT("string object exotic property get for key: %!O, arr_idx: %ld",
		                     (duk_heaphdr *) key, (long) arr_idx));

		/* XXX: charlen; avoid multiple lookups? */

		if (arr_idx != DUK__NO_ARRAY_INDEX) {
			duk_hstring *h_val;

			DUK_DDD(DUK_DDDPRINT("array index exists"));

			h_val = duk_hobject_get_internal_value_string(thr->heap, obj);
			DUK_ASSERT(h_val);
			if (arr_idx < DUK_HSTRING_GET_CHARLEN(h_val)) {
				DUK_DDD(DUK_DDDPRINT("-> found, array index inside string"));
				if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
					duk_push_hstring(thr, h_val);
					duk_substring(thr, -1, arr_idx, arr_idx + 1);  /* [str] -> [substr] */
				}
				out_desc->flags = DUK_PROPDESC_FLAG_ENUMERABLE |  /* E5 Section 15.5.5.2 */
				                  DUK_PROPDESC_FLAG_VIRTUAL;
				out_desc->get = NULL;
				out_desc->set = NULL;
				out_desc->e_idx = -1;
				out_desc->h_idx = -1;
				out_desc->a_idx = -1;

				DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj));
				goto prop_found_noexotic;  /* cannot be arguments exotic */
			} else {
				/* index is above internal string length -> property is fully normal */
				DUK_DDD(DUK_DDDPRINT("array index outside string -> normal property"));
			}
		} else if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			duk_hstring *h_val;

			DUK_DDD(DUK_DDDPRINT("-> found, key is 'length', length exotic behavior"));

			h_val = duk_hobject_get_internal_value_string(thr->heap, obj);
			DUK_ASSERT(h_val != NULL);
			if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
				duk_push_uint(thr, (duk_uint_t) DUK_HSTRING_GET_CHARLEN(h_val));
			}
			out_desc->flags = DUK_PROPDESC_FLAG_VIRTUAL;  /* E5 Section 15.5.5.1 */
			out_desc->get = NULL;
			out_desc->set = NULL;
			out_desc->e_idx = -1;
			out_desc->h_idx = -1;
			out_desc->a_idx = -1;

			DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj));
			goto prop_found_noexotic;  /* cannot be arguments exotic */
		}
	}
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	else if (DUK_HOBJECT_IS_BUFOBJ(obj)) {
		duk_hbufobj *h_bufobj;
		duk_uint_t byte_off;
		duk_small_uint_t elem_size;

		h_bufobj = (duk_hbufobj *) obj;
		DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);
		DUK_DDD(DUK_DDDPRINT("bufobj property get for key: %!O, arr_idx: %ld",
		                     (duk_heaphdr *) key, (long) arr_idx));

		if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h_bufobj)) {
			DUK_DDD(DUK_DDDPRINT("array index exists"));

			/* Careful with wrapping: arr_idx upshift may easily wrap, whereas
			 * length downshift won't.
			 */
			if (arr_idx < (h_bufobj->length >> h_bufobj->shift)) {
				byte_off = arr_idx << h_bufobj->shift;  /* no wrap assuming h_bufobj->length is valid */
				elem_size = (duk_small_uint_t) (1U << h_bufobj->shift);
				if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
					duk_uint8_t *data;

					if (h_bufobj->buf != NULL && DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_bufobj, byte_off + elem_size)) {
						data = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufobj->buf) + h_bufobj->offset + byte_off;
						duk_hbufobj_push_validated_read(thr, h_bufobj, data, elem_size);
					} else {
						DUK_D(DUK_DPRINT("bufobj access out of underlying buffer, ignoring (read zero)"));
						duk_push_uint(thr, 0);
					}
				}
				out_desc->flags = DUK_PROPDESC_FLAG_WRITABLE |
				                  DUK_PROPDESC_FLAG_VIRTUAL;
				if (DUK_HOBJECT_GET_CLASS_NUMBER(obj) != DUK_HOBJECT_CLASS_ARRAYBUFFER) {
					/* ArrayBuffer indices are non-standard and are
					 * non-enumerable to avoid their serialization.
					 */
					out_desc->flags |= DUK_PROPDESC_FLAG_ENUMERABLE;
				}
				out_desc->get = NULL;
				out_desc->set = NULL;
				out_desc->e_idx = -1;
				out_desc->h_idx = -1;
				out_desc->a_idx = -1;

				DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj));
				goto prop_found_noexotic;  /* cannot be e.g. arguments exotic, since exotic 'traits' are mutually exclusive */
			} else {
				/* index is above internal buffer length -> property is fully normal */
				DUK_DDD(DUK_DDDPRINT("array index outside buffer -> normal property"));
			}
		} else if (key == DUK_HTHREAD_STRING_LENGTH(thr) && DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h_bufobj)) {
			DUK_DDD(DUK_DDDPRINT("-> found, key is 'length', length exotic behavior"));

			if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
				/* Length in elements: take into account shift, but
				 * intentionally don't check the underlying buffer here.
				 */
				duk_push_uint(thr, h_bufobj->length >> h_bufobj->shift);
			}
			out_desc->flags = DUK_PROPDESC_FLAG_VIRTUAL;
			out_desc->get = NULL;
			out_desc->set = NULL;
			out_desc->e_idx = -1;
			out_desc->h_idx = -1;
			out_desc->a_idx = -1;

			DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj));
			goto prop_found_noexotic;  /* cannot be arguments exotic */
		}
	}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

	/* Array properties have exotic behavior but they are concrete,
	 * so no special handling here.
	 *
	 * Arguments exotic behavior (E5 Section 10.6, [[GetOwnProperty]]
	 * is only relevant as a post-check implemented below; hence no
	 * check here.
	 */

	/*
	 *  Not found as concrete or virtual.
	 */

 prop_not_found:
	DUK_DDD(DUK_DDDPRINT("-> not found (virtual, entry part, or array part)"));
	DUK_STATS_INC(thr->heap, stats_getownpropdesc_miss);
	return 0;

	/*
	 *  Found.
	 *
	 *  Arguments object has exotic post-processing, see E5 Section 10.6,
	 *  description of [[GetOwnProperty]] variant for arguments.
	 */

 prop_found:
	DUK_DDD(DUK_DDDPRINT("-> property found, checking for arguments exotic post-behavior"));

	/* Notes:
	 *  - Only numbered indices are relevant, so arr_idx fast reject is good
	 *    (this is valid unless there are more than 4**32-1 arguments).
	 *  - Since variable lookup has no side effects, this can be skipped if
	 *    DUK_GETDESC_FLAG_PUSH_VALUE is not set.
	 */

	if (DUK_UNLIKELY(DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj) &&
	                 arr_idx != DUK__NO_ARRAY_INDEX &&
	                 (flags & DUK_GETDESC_FLAG_PUSH_VALUE))) {
		duk_propdesc temp_desc;

		/* Magically bound variable cannot be an accessor.  However,
		 * there may be an accessor property (or a plain property) in
		 * place with magic behavior removed.  This happens e.g. when
		 * a magic property is redefined with defineProperty().
		 * Cannot assert for "not accessor" here.
		 */

		/* replaces top of stack with new value if necessary */
		DUK_ASSERT((flags & DUK_GETDESC_FLAG_PUSH_VALUE) != 0);

		/* This can perform a variable lookup but only into a declarative
		 * environment which has no side effects.
		 */
		if (duk__check_arguments_map_for_get(thr, obj, key, &temp_desc)) {
			DUK_DDD(DUK_DDDPRINT("-> arguments exotic behavior overrides result: %!T -> %!T",
			                     (duk_tval *) duk_get_tval(thr, -2),
			                     (duk_tval *) duk_get_tval(thr, -1)));
			/* [... old_result result] -> [... result] */
			duk_remove_m2(thr);
		}
	}

 prop_found_noexotic:
	DUK_STATS_INC(thr->heap, stats_getownpropdesc_hit);
	return 1;
}

DUK_INTERNAL duk_bool_t duk_hobject_get_own_propdesc(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *out_desc, duk_small_uint_t flags) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(out_desc != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	return duk__get_own_propdesc_raw(thr, obj, key, DUK_HSTRING_GET_ARRIDX_SLOW(key), out_desc, flags);
}

/*
 *  ECMAScript compliant [[GetProperty]](P), for internal use only.
 *
 *  If property is found:
 *    - Fills descriptor fields to 'out_desc'
 *    - If DUK_GETDESC_FLAG_PUSH_VALUE is set, pushes a value related to the
 *      property onto the stack ('undefined' for accessor properties).
 *    - Returns non-zero
 *
 *  If property is not found:
 *    - 'out_desc' is left in untouched state (possibly garbage)
 *    - Nothing is pushed onto the stack (not even with DUK_GETDESC_FLAG_PUSH_VALUE
 *      set)
 *    - Returns zero
 *
 *  May cause arbitrary side effects and invalidate (most) duk_tval
 *  pointers.
 */

DUK_LOCAL duk_bool_t duk__get_propdesc(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_propdesc *out_desc, duk_small_uint_t flags) {
	duk_hobject *curr;
	duk_uint32_t arr_idx;
	duk_uint_t sanity;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(out_desc != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_STATS_INC(thr->heap, stats_getpropdesc_count);

	arr_idx = DUK_HSTRING_GET_ARRIDX_FAST(key);

	DUK_DDD(DUK_DDDPRINT("duk__get_propdesc: thr=%p, obj=%p, key=%p, out_desc=%p, flags=%lx, "
	                     "arr_idx=%ld (obj -> %!O, key -> %!O)",
	                     (void *) thr, (void *) obj, (void *) key, (void *) out_desc,
	                     (long) flags, (long) arr_idx,
	                     (duk_heaphdr *) obj, (duk_heaphdr *) key));

	curr = obj;
	DUK_ASSERT(curr != NULL);
	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (duk__get_own_propdesc_raw(thr, curr, key, arr_idx, out_desc, flags)) {
			/* stack contains value (if requested), 'out_desc' is set */
			DUK_STATS_INC(thr->heap, stats_getpropdesc_hit);
			return 1;
		}

		/* not found in 'curr', next in prototype chain; impose max depth */
		if (DUK_UNLIKELY(sanity-- == 0)) {
			if (flags & DUK_GETDESC_FLAG_IGNORE_PROTOLOOP) {
				/* treat like property not found */
				break;
			} else {
				DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
				DUK_WO_NORETURN(return 0;);
			}
		}
		curr = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, curr);
	} while (curr != NULL);

	/* out_desc is left untouched (possibly garbage), caller must use return
	 * value to determine whether out_desc can be looked up
	 */

	DUK_STATS_INC(thr->heap, stats_getpropdesc_miss);
	return 0;
}

/*
 *  Shallow fast path checks for accessing array elements with numeric
 *  indices.  The goal is to try to avoid coercing an array index to an
 *  (interned) string for the most common lookups, in particular, for
 *  standard Array objects.
 *
 *  Interning is avoided but only for a very narrow set of cases:
 *    - Object has array part, index is within array allocation, and
 *      value is not unused (= key exists)
 *    - Object has no interfering exotic behavior (e.g. arguments or
 *      string object exotic behaviors interfere, array exotic
 *      behavior does not).
 *
 *  Current shortcoming: if key does not exist (even if it is within
 *  the array allocation range) a slow path lookup with interning is
 *  always required.  This can probably be fixed so that there is a
 *  quick fast path for non-existent elements as well, at least for
 *  standard Array objects.
 */

#if defined(DUK_USE_ARRAY_PROP_FASTPATH)
DUK_LOCAL duk_tval *duk__getprop_shallow_fastpath_array_tval(duk_hthread *thr, duk_hobject *obj, duk_tval *tv_key) {
	duk_tval *tv;
	duk_uint32_t idx;

	DUK_UNREF(thr);

	if (!(DUK_HOBJECT_HAS_ARRAY_PART(obj) &&
	     !DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj) &&
	     !DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(obj) &&
	     !DUK_HOBJECT_IS_BUFOBJ(obj) &&
	     !DUK_HOBJECT_IS_PROXY(obj))) {
		/* Must have array part and no conflicting exotic behaviors.
		 * Doesn't need to have array special behavior, e.g. Arguments
		 * object has array part.
		 */
		return NULL;
	}

	/* Arrays never have other exotic behaviors. */

	DUK_DDD(DUK_DDDPRINT("fast path attempt (no exotic string/arguments/buffer "
	                     "behavior, object has array part)"));

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_key)) {
		idx = duk__tval_fastint_to_arr_idx(tv_key);
	} else
#endif
	if (DUK_TVAL_IS_DOUBLE(tv_key)) {
		idx = duk__tval_number_to_arr_idx(tv_key);
	} else {
		DUK_DDD(DUK_DDDPRINT("key is not a number"));
		return NULL;
	}

	/* If index is not valid, idx will be DUK__NO_ARRAY_INDEX which
	 * is 0xffffffffUL.  We don't need to check for that explicitly
	 * because 0xffffffffUL will never be inside object 'a_size'.
	 */

	if (idx >= DUK_HOBJECT_GET_ASIZE(obj)) {
		DUK_DDD(DUK_DDDPRINT("key is not an array index or outside array part"));
		return NULL;
	}
	DUK_ASSERT(idx != 0xffffffffUL);
	DUK_ASSERT(idx != DUK__NO_ARRAY_INDEX);

	/* XXX: for array instances we could take a shortcut here and assume
	 * Array.prototype doesn't contain an array index property.
	 */

	DUK_DDD(DUK_DDDPRINT("key is a valid array index and inside array part"));
	tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, idx);
	if (!DUK_TVAL_IS_UNUSED(tv)) {
		DUK_DDD(DUK_DDDPRINT("-> fast path successful"));
		return tv;
	}

	DUK_DDD(DUK_DDDPRINT("fast path attempt failed, fall back to slow path"));
	return NULL;
}

DUK_LOCAL duk_bool_t duk__putprop_shallow_fastpath_array_tval(duk_hthread *thr, duk_hobject *obj, duk_tval *tv_key, duk_tval *tv_val) {
	duk_tval *tv;
	duk_harray *a;
	duk_uint32_t idx;
	duk_uint32_t old_len, new_len;

	if (!(DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj) &&
	      DUK_HOBJECT_HAS_ARRAY_PART(obj) &&
	      DUK_HOBJECT_HAS_EXTENSIBLE(obj))) {
		return 0;
	}
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));  /* caller ensures */

	a = (duk_harray *) obj;
	DUK_HARRAY_ASSERT_VALID(a);

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_key)) {
		idx = duk__tval_fastint_to_arr_idx(tv_key);
	} else
#endif
	if (DUK_TVAL_IS_DOUBLE(tv_key)) {
		idx = duk__tval_number_to_arr_idx(tv_key);
	} else {
		DUK_DDD(DUK_DDDPRINT("key is not a number"));
		return 0;
	}

	/* If index is not valid, idx will be DUK__NO_ARRAY_INDEX which
	 * is 0xffffffffUL.  We don't need to check for that explicitly
	 * because 0xffffffffUL will never be inside object 'a_size'.
	 */

	if (idx >= DUK_HOBJECT_GET_ASIZE(obj)) {  /* for resizing of array part, use slow path */
		return 0;
	}
	DUK_ASSERT(idx != 0xffffffffUL);
	DUK_ASSERT(idx != DUK__NO_ARRAY_INDEX);

	old_len = a->length;

	if (idx >= old_len) {
		DUK_DDD(DUK_DDDPRINT("write new array entry requires length update "
		                     "(arr_idx=%ld, old_len=%ld)",
		                     (long) idx, (long) old_len));
		if (DUK_HARRAY_LENGTH_NONWRITABLE(a)) {
			/* The correct behavior here is either a silent error
			 * or a TypeError, depending on strictness.  Fall back
			 * to the slow path to handle the situation.
			 */
			return 0;
		}
		new_len = idx + 1;

		((duk_harray *) obj)->length = new_len;
	}

	tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, idx);
	DUK_TVAL_SET_TVAL_UPDREF(thr, tv, tv_val);  /* side effects */

	DUK_DDD(DUK_DDDPRINT("array fast path success for index %ld", (long) idx));
	return 1;
}
#endif  /* DUK_USE_ARRAY_PROP_FASTPATH */

/*
 *  Fast path for bufobj getprop/putprop
 */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_LOCAL duk_bool_t duk__getprop_fastpath_bufobj_tval(duk_hthread *thr, duk_hobject *obj, duk_tval *tv_key) {
	duk_uint32_t idx;
	duk_hbufobj *h_bufobj;
	duk_uint_t byte_off;
	duk_small_uint_t elem_size;
	duk_uint8_t *data;

	if (!DUK_HOBJECT_IS_BUFOBJ(obj)) {
		return 0;
	}
	h_bufobj = (duk_hbufobj *) obj;
	if (!DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h_bufobj)) {
		return 0;
	}

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_key)) {
		idx = duk__tval_fastint_to_arr_idx(tv_key);
	} else
#endif
	if (DUK_TVAL_IS_DOUBLE(tv_key)) {
		idx = duk__tval_number_to_arr_idx(tv_key);
	} else {
		return 0;
	}

	/* If index is not valid, idx will be DUK__NO_ARRAY_INDEX which
	 * is 0xffffffffUL.  We don't need to check for that explicitly
	 * because 0xffffffffUL will never be inside bufobj length.
	 */

	/* Careful with wrapping (left shifting idx would be unsafe). */
	if (idx >= (h_bufobj->length >> h_bufobj->shift)) {
		return 0;
	}
	DUK_ASSERT(idx != DUK__NO_ARRAY_INDEX);

	byte_off = idx << h_bufobj->shift;  /* no wrap assuming h_bufobj->length is valid */
	elem_size = (duk_small_uint_t) (1U << h_bufobj->shift);

	if (h_bufobj->buf != NULL && DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_bufobj, byte_off + elem_size)) {
		data = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufobj->buf) + h_bufobj->offset + byte_off;
		duk_hbufobj_push_validated_read(thr, h_bufobj, data, elem_size);
	} else {
		DUK_D(DUK_DPRINT("bufobj access out of underlying buffer, ignoring (read zero)"));
		duk_push_uint(thr, 0);
	}

	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
DUK_LOCAL duk_bool_t duk__putprop_fastpath_bufobj_tval(duk_hthread *thr, duk_hobject *obj, duk_tval *tv_key, duk_tval *tv_val) {
	duk_uint32_t idx;
	duk_hbufobj *h_bufobj;
	duk_uint_t byte_off;
	duk_small_uint_t elem_size;
	duk_uint8_t *data;

	if (!(DUK_HOBJECT_IS_BUFOBJ(obj) &&
	      DUK_TVAL_IS_NUMBER(tv_val))) {
		return 0;
	}
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));  /* caller ensures; rom objects are never bufobjs now */

	h_bufobj = (duk_hbufobj *) obj;
	if (!DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h_bufobj)) {
		return 0;
	}

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_key)) {
		idx = duk__tval_fastint_to_arr_idx(tv_key);
	} else
#endif
	if (DUK_TVAL_IS_DOUBLE(tv_key)) {
		idx = duk__tval_number_to_arr_idx(tv_key);
	} else {
		return 0;
	}

	/* If index is not valid, idx will be DUK__NO_ARRAY_INDEX which
	 * is 0xffffffffUL.  We don't need to check for that explicitly
	 * because 0xffffffffUL will never be inside bufobj length.
	 */

	/* Careful with wrapping (left shifting idx would be unsafe). */
	if (idx >= (h_bufobj->length >> h_bufobj->shift)) {
		return 0;
	}
	DUK_ASSERT(idx != DUK__NO_ARRAY_INDEX);

	byte_off = idx << h_bufobj->shift;  /* no wrap assuming h_bufobj->length is valid */
	elem_size = (duk_small_uint_t) (1U << h_bufobj->shift);

	/* Value is required to be a number in the fast path so there
	 * are no side effects in write coercion.
	 */
	duk_push_tval(thr, tv_val);
	DUK_ASSERT(duk_is_number(thr, -1));

	if (h_bufobj->buf != NULL && DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_bufobj, byte_off + elem_size)) {
		data = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufobj->buf) + h_bufobj->offset + byte_off;
		duk_hbufobj_validated_write(thr, h_bufobj, data, elem_size);
	} else {
		DUK_D(DUK_DPRINT("bufobj access out of underlying buffer, ignoring (write skipped)"));
	}

	duk_pop_unsafe(thr);
	return 1;
}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

/*
 *  GETPROP: ECMAScript property read.
 */

DUK_INTERNAL duk_bool_t duk_hobject_getprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key) {
	duk_tval tv_obj_copy;
	duk_tval tv_key_copy;
	duk_hobject *curr = NULL;
	duk_hstring *key = NULL;
	duk_uint32_t arr_idx = DUK__NO_ARRAY_INDEX;
	duk_propdesc desc;
	duk_uint_t sanity;

	DUK_DDD(DUK_DDDPRINT("getprop: thr=%p, obj=%p, key=%p (obj -> %!T, key -> %!T)",
	                     (void *) thr, (void *) tv_obj, (void *) tv_key,
	                     (duk_tval *) tv_obj, (duk_tval *) tv_key));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(tv_obj != NULL);
	DUK_ASSERT(tv_key != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_STATS_INC(thr->heap, stats_getprop_all);

	/*
	 *  Make a copy of tv_obj, tv_key, and tv_val to avoid any issues of
	 *  them being invalidated by a valstack resize.
	 *
	 *  XXX: this is now an overkill for many fast paths.  Rework this
	 *  to be faster (although switching to a valstack discipline might
	 *  be a better solution overall).
	 */

	DUK_TVAL_SET_TVAL(&tv_obj_copy, tv_obj);
	DUK_TVAL_SET_TVAL(&tv_key_copy, tv_key);
	tv_obj = &tv_obj_copy;
	tv_key = &tv_key_copy;

	/*
	 *  Coercion and fast path processing
	 */

	switch (DUK_TVAL_GET_TAG(tv_obj)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL: {
		/* Note: unconditional throw */
		DUK_DDD(DUK_DDDPRINT("base object is undefined or null -> reject"));
#if defined(DUK_USE_PARANOID_ERRORS)
		DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BASE);
#else
		DUK_ERROR_FMT2(thr, DUK_ERR_TYPE_ERROR, "cannot read property %s of %s",
		               duk_push_string_tval_readable(thr, tv_key), duk_push_string_tval_readable(thr, tv_obj));
#endif
		DUK_WO_NORETURN(return 0;);
		break;
	}

	case DUK_TAG_BOOLEAN: {
		DUK_DDD(DUK_DDDPRINT("base object is a boolean, start lookup from boolean prototype"));
		curr = thr->builtins[DUK_BIDX_BOOLEAN_PROTOTYPE];
		break;
	}

	case DUK_TAG_STRING: {
		duk_hstring *h = DUK_TVAL_GET_STRING(tv_obj);
		duk_int_t pop_count;

		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			/* Symbols (ES2015 or hidden) don't have virtual properties. */
			DUK_DDD(DUK_DDDPRINT("base object is a symbol, start lookup from symbol prototype"));
			curr = thr->builtins[DUK_BIDX_SYMBOL_PROTOTYPE];
			break;
		}

#if defined(DUK_USE_FASTINT)
		if (DUK_TVAL_IS_FASTINT(tv_key)) {
			arr_idx = duk__tval_fastint_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object string, key is a fast-path fastint; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		} else
#endif
		if (DUK_TVAL_IS_NUMBER(tv_key)) {
			arr_idx = duk__tval_number_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object string, key is a fast-path number; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		} else {
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object string, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
			pop_count = 1;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HSTRING_GET_CHARLEN(h)) {
			duk_pop_n_unsafe(thr, pop_count);
			duk_push_hstring(thr, h);
			duk_substring(thr, -1, arr_idx, arr_idx + 1);  /* [str] -> [substr] */

			DUK_STATS_INC(thr->heap, stats_getprop_stringidx);
			DUK_DDD(DUK_DDDPRINT("-> %!T (base is string, key is an index inside string length "
			                     "after coercion -> return char)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			return 1;
		}

		if (pop_count == 0) {
			/* This is a pretty awkward control flow, but we need to recheck the
			 * key coercion here.
			 */
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object string, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
		}

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			duk_pop_unsafe(thr);  /* [key] -> [] */
			duk_push_uint(thr, (duk_uint_t) DUK_HSTRING_GET_CHARLEN(h));  /* [] -> [res] */

			DUK_STATS_INC(thr->heap, stats_getprop_stringlen);
			DUK_DDD(DUK_DDDPRINT("-> %!T (base is string, key is 'length' after coercion -> "
			                     "return string length)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			return 1;
		}

		DUK_DDD(DUK_DDDPRINT("base object is a string, start lookup from string prototype"));
		curr = thr->builtins[DUK_BIDX_STRING_PROTOTYPE];
		goto lookup;  /* avoid double coercion */
	}

	case DUK_TAG_OBJECT: {
#if defined(DUK_USE_ARRAY_PROP_FASTPATH)
		duk_tval *tmp;
#endif

		curr = DUK_TVAL_GET_OBJECT(tv_obj);
		DUK_ASSERT(curr != NULL);

		/* XXX: array .length fast path (important in e.g. loops)? */

#if defined(DUK_USE_ARRAY_PROP_FASTPATH)
		tmp = duk__getprop_shallow_fastpath_array_tval(thr, curr, tv_key);
		if (tmp) {
			duk_push_tval(thr, tmp);

			DUK_DDD(DUK_DDDPRINT("-> %!T (base is object, key is a number, array part "
			                     "fast path)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			DUK_STATS_INC(thr->heap, stats_getprop_arrayidx);
			return 1;
		}
#endif

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		if (duk__getprop_fastpath_bufobj_tval(thr, curr, tv_key) != 0) {
			/* Read value pushed on stack. */
			DUK_DDD(DUK_DDDPRINT("-> %!T (base is bufobj, key is a number, bufobj "
			                     "fast path)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			DUK_STATS_INC(thr->heap, stats_getprop_bufobjidx);
			return 1;
		}
#endif

#if defined(DUK_USE_ES6_PROXY)
		if (DUK_UNLIKELY(DUK_HOBJECT_IS_PROXY(curr))) {
			duk_hobject *h_target;

			if (duk__proxy_check_prop(thr, curr, DUK_STRIDX_GET, tv_key, &h_target)) {
				/* -> [ ... trap handler ] */
				DUK_DDD(DUK_DDDPRINT("-> proxy object 'get' for key %!T", (duk_tval *) tv_key));
				DUK_STATS_INC(thr->heap, stats_getprop_proxy);
				duk_push_hobject(thr, h_target);  /* target */
				duk_push_tval(thr, tv_key);       /* P */
				duk_push_tval(thr, tv_obj);       /* Receiver: Proxy object */
				duk_call_method(thr, 3 /*nargs*/);

				/* Target object must be checked for a conflicting
				 * non-configurable property.
				 */
				arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
				DUK_ASSERT(key != NULL);

				if (duk__get_own_propdesc_raw(thr, h_target, key, arr_idx, &desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
					duk_tval *tv_hook = duk_require_tval(thr, -3);  /* value from hook */
					duk_tval *tv_targ = duk_require_tval(thr, -1);  /* value from target */
					duk_bool_t datadesc_reject;
					duk_bool_t accdesc_reject;

					DUK_DDD(DUK_DDDPRINT("proxy 'get': target has matching property %!O, check for "
					                     "conflicting property; tv_hook=%!T, tv_targ=%!T, desc.flags=0x%08lx, "
					                     "desc.get=%p, desc.set=%p",
					                     (duk_heaphdr *) key, (duk_tval *) tv_hook, (duk_tval *) tv_targ,
					                     (unsigned long) desc.flags,
					                     (void *) desc.get, (void *) desc.set));

					datadesc_reject = !(desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) &&
					                  !(desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) &&
					                  !(desc.flags & DUK_PROPDESC_FLAG_WRITABLE) &&
					                  !duk_js_samevalue(tv_hook, tv_targ);
					accdesc_reject = (desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) &&
					                 !(desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) &&
					                 (desc.get == NULL) &&
					                 !DUK_TVAL_IS_UNDEFINED(tv_hook);
					if (datadesc_reject || accdesc_reject) {
						DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
						DUK_WO_NORETURN(return 0;);
					}

					duk_pop_2_unsafe(thr);
				} else {
					duk_pop_unsafe(thr);
				}
				return 1;  /* return value */
			}

			curr = h_target;  /* resume lookup from target */
			DUK_TVAL_SET_OBJECT(tv_obj, curr);
		}
#endif  /* DUK_USE_ES6_PROXY */

		if (DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(curr)) {
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);

			DUK_STATS_INC(thr->heap, stats_getprop_arguments);
			if (duk__check_arguments_map_for_get(thr, curr, key, &desc)) {
				DUK_DDD(DUK_DDDPRINT("-> %!T (base is object with arguments exotic behavior, "
				                     "key matches magically bound property -> skip standard "
				                     "Get with replacement value)",
				                     (duk_tval *) duk_get_tval(thr, -1)));

				/* no need for 'caller' post-check, because 'key' must be an array index */

				duk_remove_m2(thr);  /* [key result] -> [result] */
				return 1;
			}

			goto lookup;  /* avoid double coercion */
		}
		break;
	}

	/* Buffer has virtual properties similar to string, but indexed values
	 * are numbers, not 1-byte buffers/strings which would perform badly.
	 */
	case DUK_TAG_BUFFER: {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv_obj);
		duk_int_t pop_count;

		/*
		 *  Because buffer values are often looped over, a number fast path
		 *  is important.
		 */

#if defined(DUK_USE_FASTINT)
		if (DUK_TVAL_IS_FASTINT(tv_key)) {
			arr_idx = duk__tval_fastint_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a fast-path fastint; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		}
		else
#endif
		if (DUK_TVAL_IS_NUMBER(tv_key)) {
			arr_idx = duk__tval_number_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a fast-path number; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		} else {
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
			pop_count = 1;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HBUFFER_GET_SIZE(h)) {
			duk_pop_n_unsafe(thr, pop_count);
			duk_push_uint(thr, ((duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h))[arr_idx]);
			DUK_STATS_INC(thr->heap, stats_getprop_bufferidx);
			DUK_DDD(DUK_DDDPRINT("-> %!T (base is buffer, key is an index inside buffer length "
			                     "after coercion -> return byte as number)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			return 1;
		}

		if (pop_count == 0) {
			/* This is a pretty awkward control flow, but we need to recheck the
			 * key coercion here.
			 */
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
		}

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			duk_pop_unsafe(thr);  /* [key] -> [] */
			duk_push_uint(thr, (duk_uint_t) DUK_HBUFFER_GET_SIZE(h));  /* [] -> [res] */
			DUK_STATS_INC(thr->heap, stats_getprop_bufferlen);

			DUK_DDD(DUK_DDDPRINT("-> %!T (base is buffer, key is 'length' "
			                     "after coercion -> return buffer length)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			return 1;
		}

		DUK_DDD(DUK_DDDPRINT("base object is a buffer, start lookup from Uint8Array prototype"));
		curr = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
		goto lookup;  /* avoid double coercion */
	}

	case DUK_TAG_POINTER: {
		DUK_DDD(DUK_DDDPRINT("base object is a pointer, start lookup from pointer prototype"));
		curr = thr->builtins[DUK_BIDX_POINTER_PROTOTYPE];
		break;
	}

	case DUK_TAG_LIGHTFUNC: {
		/* Lightfuncs inherit getter .name and .length from %NativeFunctionPrototype%. */
		DUK_DDD(DUK_DDDPRINT("base object is a lightfunc, start lookup from function prototype"));
		curr = thr->builtins[DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE];
		break;
	}

#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default: {
		/* number */
		DUK_DDD(DUK_DDDPRINT("base object is a number, start lookup from number prototype"));
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_obj));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_obj));
		curr = thr->builtins[DUK_BIDX_NUMBER_PROTOTYPE];
		break;
	}
	}

	/* key coercion (unless already coerced above) */
	DUK_ASSERT(key == NULL);
	arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
	DUK_ASSERT(key != NULL);
	/*
	 *  Property lookup
	 */

 lookup:
	/* [key] (coerced) */
	DUK_ASSERT(curr != NULL);
	DUK_ASSERT(key != NULL);

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (!duk__get_own_propdesc_raw(thr, curr, key, arr_idx, &desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
			goto next_in_chain;
		}

		if (desc.get != NULL) {
			/* accessor with defined getter */
			DUK_ASSERT((desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) != 0);

			duk_pop_unsafe(thr);              /* [key undefined] -> [key] */
			duk_push_hobject(thr, desc.get);
			duk_push_tval(thr, tv_obj);       /* note: original, uncoerced base */
#if defined(DUK_USE_NONSTD_GETTER_KEY_ARGUMENT)
			duk_dup_m3(thr);
			duk_call_method(thr, 1);          /* [key getter this key] -> [key retval] */
#else
			duk_call_method(thr, 0);          /* [key getter this] -> [key retval] */
#endif
		} else {
			/* [key value] or [key undefined] */

			/* data property or accessor without getter */
			DUK_ASSERT(((desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) == 0) ||
			           (desc.get == NULL));

			/* if accessor without getter, return value is undefined */
			DUK_ASSERT(((desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) == 0) ||
			           duk_is_undefined(thr, -1));

			/* Note: for an accessor without getter, falling through to
			 * check for "caller" exotic behavior is unnecessary as
			 * "undefined" will never activate the behavior.  But it does
			 * no harm, so we'll do it anyway.
			 */
		}

		goto found;  /* [key result] */

	 next_in_chain:
		/* XXX: option to pretend property doesn't exist if sanity limit is
		 * hit might be useful.
		 */
		if (DUK_UNLIKELY(sanity-- == 0)) {
			DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
			DUK_WO_NORETURN(return 0;);
		}
		curr = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, curr);
	} while (curr != NULL);

	/*
	 *  Not found
	 */

	duk_to_undefined(thr, -1);  /* [key] -> [undefined] (default value) */

	DUK_DDD(DUK_DDDPRINT("-> %!T (not found)", (duk_tval *) duk_get_tval(thr, -1)));
	return 0;

	/*
	 *  Found; post-processing (Function and arguments objects)
	 */

 found:
	/* [key result] */

#if !defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	/* Special behavior for 'caller' property of (non-bound) function objects
	 * and non-strict Arguments objects: if 'caller' -value- (!) is a strict
	 * mode function, throw a TypeError (E5 Sections 15.3.5.4, 10.6).
	 * Quite interestingly, a non-strict function with no formal arguments
	 * will get an arguments object -without- special 'caller' behavior!
	 *
	 * The E5.1 spec is a bit ambiguous if this special behavior applies when
	 * a bound function is the base value (not the 'caller' value): Section
	 * 15.3.4.5 (describing bind()) states that [[Get]] for bound functions
	 * matches that of Section 15.3.5.4 ([[Get]] for Function instances).
	 * However, Section 13.3.5.4 has "NOTE: Function objects created using
	 * Function.prototype.bind use the default [[Get]] internal method."
	 * The current implementation assumes this means that bound functions
	 * should not have the special [[Get]] behavior.
	 *
	 * The E5.1 spec is also a bit unclear if the TypeError throwing is
	 * applied if the 'caller' value is a strict bound function.  The
	 * current implementation will throw even for both strict non-bound
	 * and strict bound functions.
	 *
	 * See test-dev-strict-func-as-caller-prop-value.js for quite extensive
	 * tests.
	 *
	 * This exotic behavior is disabled when the non-standard 'caller' property
	 * is enabled, as it conflicts with the free use of 'caller'.
	 */
	if (key == DUK_HTHREAD_STRING_CALLER(thr) &&
	    DUK_TVAL_IS_OBJECT(tv_obj)) {
		duk_hobject *orig = DUK_TVAL_GET_OBJECT(tv_obj);
		DUK_ASSERT(orig != NULL);

		if (DUK_HOBJECT_IS_NONBOUND_FUNCTION(orig) ||
		    DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(orig)) {
			duk_hobject *h;

			/* XXX: The TypeError is currently not applied to bound
			 * functions because the 'strict' flag is not copied by
			 * bind().  This may or may not be correct, the specification
			 * only refers to the value being a "strict mode Function
			 * object" which is ambiguous.
			 */
			DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(orig));

			h = duk_get_hobject(thr, -1);  /* NULL if not an object */
			if (h &&
			    DUK_HOBJECT_IS_FUNCTION(h) &&
			    DUK_HOBJECT_HAS_STRICT(h)) {
				/* XXX: sufficient to check 'strict', assert for 'is function' */
				DUK_ERROR_TYPE(thr, DUK_STR_STRICT_CALLER_READ);
				DUK_WO_NORETURN(return 0;);
			}
		}
	}
#endif   /* !DUK_USE_NONSTD_FUNC_CALLER_PROPERTY */

	duk_remove_m2(thr);  /* [key result] -> [result] */

	DUK_DDD(DUK_DDDPRINT("-> %!T (found)", (duk_tval *) duk_get_tval(thr, -1)));
	return 1;
}

/*
 *  HASPROP: ECMAScript property existence check ("in" operator).
 *
 *  Interestingly, the 'in' operator does not do any coercion of
 *  the target object.
 */

DUK_INTERNAL duk_bool_t duk_hobject_hasprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key) {
	duk_tval tv_key_copy;
	duk_hobject *obj;
	duk_hstring *key;
	duk_uint32_t arr_idx;
	duk_bool_t rc;
	duk_propdesc desc;

	DUK_DDD(DUK_DDDPRINT("hasprop: thr=%p, obj=%p, key=%p (obj -> %!T, key -> %!T)",
	                     (void *) thr, (void *) tv_obj, (void *) tv_key,
	                     (duk_tval *) tv_obj, (duk_tval *) tv_key));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(tv_obj != NULL);
	DUK_ASSERT(tv_key != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_TVAL_SET_TVAL(&tv_key_copy, tv_key);
	tv_key = &tv_key_copy;

	/*
	 *  The 'in' operator requires an object as its right hand side,
	 *  throwing a TypeError unconditionally if this is not the case.
	 *
	 *  However, lightfuncs need to behave like fully fledged objects
	 *  here to be maximally transparent, so we need to handle them
	 *  here.  Same goes for plain buffers which behave like ArrayBuffers.
	 */

	/* XXX: Refactor key coercion so that it's only called once.  It can't
	 * be trivially lifted here because the object must be type checked
	 * first.
	 */

	if (DUK_TVAL_IS_OBJECT(tv_obj)) {
		obj = DUK_TVAL_GET_OBJECT(tv_obj);
		DUK_ASSERT(obj != NULL);

		arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
	} else if (DUK_TVAL_IS_BUFFER(tv_obj)) {
		arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
		if (duk__key_is_plain_buf_ownprop(thr, DUK_TVAL_GET_BUFFER(tv_obj), key, arr_idx)) {
			rc = 1;
			goto pop_and_return;
		}
		obj = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv_obj)) {
		arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);

		/* If not found, resume existence check from %NativeFunctionPrototype%.
		 * We can just substitute the value in this case; nothing will
		 * need the original base value (as would be the case with e.g.
		 * setters/getters.
		 */
		obj = thr->builtins[DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE];
	} else {
		/* Note: unconditional throw */
		DUK_DDD(DUK_DDDPRINT("base object is not an object -> reject"));
		DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BASE);
		DUK_WO_NORETURN(return 0;);
	}

	/* XXX: fast path for arrays? */

	DUK_ASSERT(key != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_UNREF(arr_idx);

#if defined(DUK_USE_ES6_PROXY)
	if (DUK_UNLIKELY(DUK_HOBJECT_IS_PROXY(obj))) {
		duk_hobject *h_target;
		duk_bool_t tmp_bool;

		/* XXX: the key in 'key in obj' is string coerced before we're called
		 * (which is the required behavior in E5/E5.1/E6) so the key is a string
		 * here already.
		 */

		if (duk__proxy_check_prop(thr, obj, DUK_STRIDX_HAS, tv_key, &h_target)) {
			/* [ ... key trap handler ] */
			DUK_DDD(DUK_DDDPRINT("-> proxy object 'has' for key %!T", (duk_tval *) tv_key));
			duk_push_hobject(thr, h_target);  /* target */
			duk_push_tval(thr, tv_key);       /* P */
			duk_call_method(thr, 2 /*nargs*/);
			tmp_bool = duk_to_boolean_top_pop(thr);
			if (!tmp_bool) {
				/* Target object must be checked for a conflicting
				 * non-configurable property.
				 */

				if (duk__get_own_propdesc_raw(thr, h_target, key, arr_idx, &desc, 0 /*flags*/)) {  /* don't push value */
					DUK_DDD(DUK_DDDPRINT("proxy 'has': target has matching property %!O, check for "
					                     "conflicting property; desc.flags=0x%08lx, "
					                     "desc.get=%p, desc.set=%p",
					                     (duk_heaphdr *) key, (unsigned long) desc.flags,
					                     (void *) desc.get, (void *) desc.set));
					/* XXX: Extensibility check for target uses IsExtensible().  If we
					 * implemented the isExtensible trap and didn't reject proxies as
					 * proxy targets, it should be respected here.
					 */
					if (!((desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) &&  /* property is configurable and */
					      DUK_HOBJECT_HAS_EXTENSIBLE(h_target))) {          /* ... target is extensible */
						DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
						DUK_WO_NORETURN(return 0;);
					}
				}
			}

			duk_pop_unsafe(thr);  /* [ key ] -> [] */
			return tmp_bool;
		}

		obj = h_target;  /* resume check from proxy target */
	}
#endif  /* DUK_USE_ES6_PROXY */

	/* XXX: inline into a prototype walking loop? */

	rc = duk__get_propdesc(thr, obj, key, &desc, 0 /*flags*/);  /* don't push value */
	/* fall through */

 pop_and_return:
	duk_pop_unsafe(thr);  /* [ key ] -> [] */
	return rc;
}

/*
 *  HASPROP variant used internally.
 *
 *  This primitive must never throw an error, callers rely on this.
 *  In particular, don't throw an error for prototype loops; instead,
 *  pretend like the property doesn't exist if a prototype sanity limit
 *  is reached.
 *
 *  Does not implement proxy behavior: if applied to a proxy object,
 *  returns key existence on the proxy object itself.
 */

DUK_INTERNAL duk_bool_t duk_hobject_hasprop_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key) {
	duk_propdesc dummy;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	return duk__get_propdesc(thr, obj, key, &dummy, DUK_GETDESC_FLAG_IGNORE_PROTOLOOP);  /* don't push value */
}

/*
 *  Helper: handle Array object 'length' write which automatically
 *  deletes properties, see E5 Section 15.4.5.1, step 3.  This is
 *  quite tricky to get right.
 *
 *  Used by duk_hobject_putprop().
 */

/* Coerce a new .length candidate to a number and check that it's a valid
 * .length.
 */
DUK_LOCAL duk_uint32_t duk__to_new_array_length_checked(duk_hthread *thr, duk_tval *tv) {
	duk_uint32_t res;
	duk_double_t d;

#if !defined(DUK_USE_PREFER_SIZE)
#if defined(DUK_USE_FASTINT)
	/* When fastints are enabled, the most interesting case is assigning
	 * a fastint to .length (e.g. arr.length = 0).
	 */
	if (DUK_TVAL_IS_FASTINT(tv)) {
		/* Very common case. */
		duk_int64_t fi;
		fi = DUK_TVAL_GET_FASTINT(tv);
		if (fi < 0 || fi > DUK_I64_CONSTANT(0xffffffff)) {
			goto fail_range;
		}
		return (duk_uint32_t) fi;
	}
#else  /* DUK_USE_FASTINT */
	/* When fastints are not enabled, the most interesting case is any
	 * number.
	 */
	if (DUK_TVAL_IS_DOUBLE(tv)) {
		d = DUK_TVAL_GET_NUMBER(tv);
	}
#endif  /* DUK_USE_FASTINT */
	else
#endif  /* !DUK_USE_PREFER_SIZE */
	{
		/* In all other cases, and when doing a size optimized build,
		 * fall back to the comprehensive handler.
		 */
		d = duk_js_tonumber(thr, tv);
	}

	/* Refuse to update an Array's 'length' to a value outside the
	 * 32-bit range.  Negative zero is accepted as zero.
	 */
	res = duk_double_to_uint32_t(d);
	if (!duk_double_equals((duk_double_t) res, d)) {
		goto fail_range;
	}

	return res;

 fail_range:
	DUK_ERROR_RANGE(thr, DUK_STR_INVALID_ARRAY_LENGTH);
	DUK_WO_NORETURN(return 0;);
}

/* Delete elements required by a smaller length, taking into account
 * potentially non-configurable elements.  Returns non-zero if all
 * elements could be deleted, and zero if all or some elements could
 * not be deleted.  Also writes final "target length" to 'out_result_len'.
 * This is the length value that should go into the 'length' property
 * (must be set by the caller).  Never throws an error.
 */
DUK_LOCAL
duk_bool_t duk__handle_put_array_length_smaller(duk_hthread *thr,
                                                duk_hobject *obj,
                                                duk_uint32_t old_len,
                                                duk_uint32_t new_len,
                                                duk_bool_t force_flag,
                                                duk_uint32_t *out_result_len) {
	duk_uint32_t target_len;
	duk_uint_fast32_t i;
	duk_uint32_t arr_idx;
	duk_hstring *key;
	duk_tval *tv;
	duk_bool_t rc;

	DUK_DDD(DUK_DDDPRINT("new array length smaller than old (%ld -> %ld), "
	                     "probably need to remove elements",
	                     (long) old_len, (long) new_len));

	/*
	 *  New length is smaller than old length, need to delete properties above
	 *  the new length.
	 *
	 *  If array part exists, this is straightforward: array entries cannot
	 *  be non-configurable so this is guaranteed to work.
	 *
	 *  If array part does not exist, array-indexed values are scattered
	 *  in the entry part, and some may not be configurable (preventing length
	 *  from becoming lower than their index + 1).  To handle the algorithm
	 *  in E5 Section 15.4.5.1, step l correctly, we scan the entire property
	 *  set twice.
	 */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(new_len < old_len);
	DUK_ASSERT(out_result_len != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj));
	DUK_ASSERT(DUK_HOBJECT_IS_ARRAY(obj));

	if (DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
		/*
		 *  All defined array-indexed properties are in the array part
		 *  (we assume the array part is comprehensive), and all array
		 *  entries are writable, configurable, and enumerable.  Thus,
		 *  nothing can prevent array entries from being deleted.
		 */

		DUK_DDD(DUK_DDDPRINT("have array part, easy case"));

		if (old_len < DUK_HOBJECT_GET_ASIZE(obj)) {
			/* XXX: assertion that entries >= old_len are already unused */
			i = old_len;
		} else {
			i = DUK_HOBJECT_GET_ASIZE(obj);
		}
		DUK_ASSERT(i <= DUK_HOBJECT_GET_ASIZE(obj));

		while (i > new_len) {
			i--;
			tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, i);
			DUK_TVAL_SET_UNUSED_UPDREF(thr, tv);  /* side effects */
		}

		*out_result_len = new_len;
		return 1;
	} else {
		/*
		 *  Entries part is a bit more complex.
		 */

		/* Stage 1: find highest preventing non-configurable entry (if any).
		 * When forcing, ignore non-configurability.
		 */

		DUK_DDD(DUK_DDDPRINT("no array part, slow case"));

		DUK_DDD(DUK_DDDPRINT("array length write, no array part, stage 1: find target_len "
		                     "(highest preventing non-configurable entry (if any))"));

		target_len = new_len;
		if (force_flag) {
			DUK_DDD(DUK_DDDPRINT("array length write, no array part; force flag -> skip stage 1"));
			goto skip_stage1;
		}
		for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
			key = DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i);
			if (!key) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: null key", (long) i));
				continue;
			}
			if (!DUK_HSTRING_HAS_ARRIDX(key)) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: key not an array index", (long) i));
				continue;
			}

			DUK_ASSERT(DUK_HSTRING_HAS_ARRIDX(key));  /* XXX: macro checks for array index flag, which is unnecessary here */
			arr_idx = DUK_HSTRING_GET_ARRIDX_SLOW(key);
			DUK_ASSERT(arr_idx != DUK__NO_ARRAY_INDEX);
			DUK_ASSERT(arr_idx < old_len);  /* consistency requires this */

			if (arr_idx < new_len) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: key is array index %ld, below new_len",
				                     (long) i, (long) arr_idx));
				continue;
			}
			if (DUK_HOBJECT_E_SLOT_IS_CONFIGURABLE(thr->heap, obj, i)) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: key is a relevant array index %ld, but configurable",
				                     (long) i, (long) arr_idx));
				continue;
			}

			/* relevant array index is non-configurable, blocks write */
			if (arr_idx >= target_len) {
				DUK_DDD(DUK_DDDPRINT("entry at index %ld has arr_idx %ld, is not configurable, "
				                     "update target_len %ld -> %ld",
				                     (long) i, (long) arr_idx, (long) target_len,
				                     (long) (arr_idx + 1)));
				target_len = arr_idx + 1;
			}
		}
	 skip_stage1:

		/* stage 2: delete configurable entries above target length */

		DUK_DDD(DUK_DDDPRINT("old_len=%ld, new_len=%ld, target_len=%ld",
		                     (long) old_len, (long) new_len, (long) target_len));

		DUK_DDD(DUK_DDDPRINT("array length write, no array part, stage 2: remove "
		                     "entries >= target_len"));

		for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
			key = DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i);
			if (!key) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: null key", (long) i));
				continue;
			}
			if (!DUK_HSTRING_HAS_ARRIDX(key)) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: key not an array index", (long) i));
				continue;
			}

			DUK_ASSERT(DUK_HSTRING_HAS_ARRIDX(key));  /* XXX: macro checks for array index flag, which is unnecessary here */
			arr_idx = DUK_HSTRING_GET_ARRIDX_SLOW(key);
			DUK_ASSERT(arr_idx != DUK__NO_ARRAY_INDEX);
			DUK_ASSERT(arr_idx < old_len);  /* consistency requires this */

			if (arr_idx < target_len) {
				DUK_DDD(DUK_DDDPRINT("skip entry index %ld: key is array index %ld, below target_len",
				                     (long) i, (long) arr_idx));
				continue;
			}
			DUK_ASSERT(force_flag || DUK_HOBJECT_E_SLOT_IS_CONFIGURABLE(thr->heap, obj, i));  /* stage 1 guarantees */

			DUK_DDD(DUK_DDDPRINT("delete entry index %ld: key is array index %ld",
			                     (long) i, (long) arr_idx));

			/*
			 *  Slow delete, but we don't care as we're already in a very slow path.
			 *  The delete always succeeds: key has no exotic behavior, property
			 *  is configurable, and no resize occurs.
			 */
			rc = duk_hobject_delprop_raw(thr, obj, key, force_flag ? DUK_DELPROP_FLAG_FORCE : 0);
			DUK_UNREF(rc);
			DUK_ASSERT(rc != 0);
		}

		/* stage 3: update length (done by caller), decide return code */

		DUK_DDD(DUK_DDDPRINT("array length write, no array part, stage 3: update length (done by caller)"));

		*out_result_len = target_len;

		if (target_len == new_len) {
			DUK_DDD(DUK_DDDPRINT("target_len matches new_len, return success"));
			return 1;
		}
		DUK_DDD(DUK_DDDPRINT("target_len does not match new_len (some entry prevented "
		                     "full length adjustment), return error"));
		return 0;
	}

	DUK_UNREACHABLE();
}

/* XXX: is valstack top best place for argument? */
DUK_LOCAL duk_bool_t duk__handle_put_array_length(duk_hthread *thr, duk_hobject *obj) {
	duk_harray *a;
	duk_uint32_t old_len;
	duk_uint32_t new_len;
	duk_uint32_t result_len;
	duk_bool_t rc;

	DUK_DDD(DUK_DDDPRINT("handling a put operation to array 'length' exotic property, "
	                     "new val: %!T",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(obj != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj));
	DUK_ASSERT(DUK_HOBJECT_IS_ARRAY(obj));
	a = (duk_harray *) obj;
	DUK_HARRAY_ASSERT_VALID(a);

	DUK_ASSERT(duk_is_valid_index(thr, -1));

	/*
	 *  Get old and new length
	 */

	old_len = a->length;
	new_len = duk__to_new_array_length_checked(thr, DUK_GET_TVAL_NEGIDX(thr, -1));
	DUK_DDD(DUK_DDDPRINT("old_len=%ld, new_len=%ld", (long) old_len, (long) new_len));

	/*
	 *  Writability check
	 */

	if (DUK_HARRAY_LENGTH_NONWRITABLE(a)) {
		DUK_DDD(DUK_DDDPRINT("length is not writable, fail"));
		return 0;
	}

	/*
	 *  New length not lower than old length => no changes needed
	 *  (not even array allocation).
	 */

	if (new_len >= old_len) {
		DUK_DDD(DUK_DDDPRINT("new length is same or higher than old length, just update length, no deletions"));
		a->length = new_len;
		return 1;
	}

	DUK_DDD(DUK_DDDPRINT("new length is lower than old length, probably must delete entries"));

	/*
	 *  New length lower than old length => delete elements, then
	 *  update length.
	 *
	 *  Note: even though a bunch of elements have been deleted, the 'desc' is
	 *  still valid as properties haven't been resized (and entries compacted).
	 */

	rc = duk__handle_put_array_length_smaller(thr, obj, old_len, new_len, 0 /*force_flag*/, &result_len);
	DUK_ASSERT(result_len >= new_len && result_len <= old_len);

	a->length = result_len;

	/* XXX: shrink array allocation or entries compaction here? */

	return rc;
}

/*
 *  PUTPROP: ECMAScript property write.
 *
 *  Unlike ECMAScript primitive which returns nothing, returns 1 to indicate
 *  success and 0 to indicate failure (assuming throw is not set).
 *
 *  This is an extremely tricky function.  Some examples:
 *
 *    * Currently a decref may trigger a GC, which may compact an object's
 *      property allocation.  Consequently, any entry indices (e_idx) will
 *      be potentially invalidated by a decref.
 *
 *    * Exotic behaviors (strings, arrays, arguments object) require,
 *      among other things:
 *
 *      - Preprocessing before and postprocessing after an actual property
 *        write.  For example, array index write requires pre-checking the
 *        array 'length' property for access control, and may require an
 *        array 'length' update after the actual write has succeeded (but
 *        not if it fails).
 *
 *      - Deletion of multiple entries, as a result of array 'length' write.
 *
 *    * Input values are taken as pointers which may point to the valstack.
 *      If valstack is resized because of the put (this may happen at least
 *      when the array part is abandoned), the pointers can be invalidated.
 *      (We currently make a copy of all of the input values to avoid issues.)
 */

DUK_INTERNAL duk_bool_t duk_hobject_putprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key, duk_tval *tv_val, duk_bool_t throw_flag) {
	duk_tval tv_obj_copy;
	duk_tval tv_key_copy;
	duk_tval tv_val_copy;
	duk_hobject *orig = NULL;  /* NULL if tv_obj is primitive */
	duk_hobject *curr;
	duk_hstring *key = NULL;
	duk_propdesc desc;
	duk_tval *tv;
	duk_uint32_t arr_idx;
	duk_bool_t rc;
	duk_int_t e_idx;
	duk_uint_t sanity;
	duk_uint32_t new_array_length = 0;  /* 0 = no update */

	DUK_DDD(DUK_DDDPRINT("putprop: thr=%p, obj=%p, key=%p, val=%p, throw=%ld "
	                     "(obj -> %!T, key -> %!T, val -> %!T)",
	                     (void *) thr, (void *) tv_obj, (void *) tv_key, (void *) tv_val,
	                     (long) throw_flag, (duk_tval *) tv_obj, (duk_tval *) tv_key, (duk_tval *) tv_val));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(tv_obj != NULL);
	DUK_ASSERT(tv_key != NULL);
	DUK_ASSERT(tv_val != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	DUK_STATS_INC(thr->heap, stats_putprop_all);

	/*
	 *  Make a copy of tv_obj, tv_key, and tv_val to avoid any issues of
	 *  them being invalidated by a valstack resize.
	 *
	 *  XXX: this is an overkill for some paths, so optimize this later
	 *  (or maybe switch to a stack arguments model entirely).
	 */

	DUK_TVAL_SET_TVAL(&tv_obj_copy, tv_obj);
	DUK_TVAL_SET_TVAL(&tv_key_copy, tv_key);
	DUK_TVAL_SET_TVAL(&tv_val_copy, tv_val);
	tv_obj = &tv_obj_copy;
	tv_key = &tv_key_copy;
	tv_val = &tv_val_copy;

	/*
	 *  Coercion and fast path processing.
	 */

	switch (DUK_TVAL_GET_TAG(tv_obj)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL: {
		/* Note: unconditional throw */
		DUK_DDD(DUK_DDDPRINT("base object is undefined or null -> reject (object=%!iT)",
		                     (duk_tval *) tv_obj));
#if defined(DUK_USE_PARANOID_ERRORS)
		DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BASE);
#else
		DUK_ERROR_FMT2(thr, DUK_ERR_TYPE_ERROR, "cannot write property %s of %s",
		               duk_push_string_tval_readable(thr, tv_key), duk_push_string_tval_readable(thr, tv_obj));
#endif
		DUK_WO_NORETURN(return 0;);
		break;
	}

	case DUK_TAG_BOOLEAN: {
		DUK_DDD(DUK_DDDPRINT("base object is a boolean, start lookup from boolean prototype"));
		curr = thr->builtins[DUK_BIDX_BOOLEAN_PROTOTYPE];
		break;
	}

	case DUK_TAG_STRING: {
		duk_hstring *h = DUK_TVAL_GET_STRING(tv_obj);

		/*
		 *  Note: currently no fast path for array index writes.
		 *  They won't be possible anyway as strings are immutable.
		 */

		DUK_ASSERT(key == NULL);
		arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
		DUK_ASSERT(key != NULL);

		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			/* Symbols (ES2015 or hidden) don't have virtual properties. */
			curr = thr->builtins[DUK_BIDX_SYMBOL_PROTOTYPE];
			goto lookup;
		}

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			goto fail_not_writable;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HSTRING_GET_CHARLEN(h)) {
			goto fail_not_writable;
		}

		DUK_DDD(DUK_DDDPRINT("base object is a string, start lookup from string prototype"));
		curr = thr->builtins[DUK_BIDX_STRING_PROTOTYPE];
		goto lookup;  /* avoid double coercion */
	}

	case DUK_TAG_OBJECT: {
		orig = DUK_TVAL_GET_OBJECT(tv_obj);
		DUK_ASSERT(orig != NULL);

#if defined(DUK_USE_ROM_OBJECTS)
		/* With this check in place fast paths won't need read-only
		 * object checks.  This is technically incorrect if there are
		 * setters that cause no writes to ROM objects, but current
		 * built-ins don't have such setters.
		 */
		if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) orig)) {
			DUK_DD(DUK_DDPRINT("attempt to putprop on read-only target object"));
			goto fail_not_writable_no_pop;  /* Must avoid duk_pop() in exit path */
		}
#endif

		/* The fast path for array property put is not fully compliant:
		 * If one places conflicting number-indexed properties into
		 * Array.prototype (for example, a non-writable Array.prototype[7])
		 * the fast path will incorrectly ignore them.
		 *
		 * This fast path could be made compliant by falling through
		 * to the slow path if the previous value was UNUSED.  This would
		 * also remove the need to check for extensibility.  Right now a
		 * non-extensible array is slower than an extensible one as far
		 * as writes are concerned.
		 *
		 * The fast path behavior is documented in more detail here:
		 * tests/ecmascript/test-misc-array-fast-write.js
		 */

		/* XXX: array .length? */

#if defined(DUK_USE_ARRAY_PROP_FASTPATH)
		if (duk__putprop_shallow_fastpath_array_tval(thr, orig, tv_key, tv_val) != 0) {
			DUK_DDD(DUK_DDDPRINT("array fast path success"));
			DUK_STATS_INC(thr->heap, stats_putprop_arrayidx);
			return 1;
		}
#endif

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		if (duk__putprop_fastpath_bufobj_tval(thr, orig, tv_key, tv_val) != 0) {
			DUK_DDD(DUK_DDDPRINT("base is bufobj, key is a number, bufobj fast path"));
			DUK_STATS_INC(thr->heap, stats_putprop_bufobjidx);
			return 1;
		}
#endif

#if defined(DUK_USE_ES6_PROXY)
		if (DUK_UNLIKELY(DUK_HOBJECT_IS_PROXY(orig))) {
			duk_hobject *h_target;
			duk_bool_t tmp_bool;

			if (duk__proxy_check_prop(thr, orig, DUK_STRIDX_SET, tv_key, &h_target)) {
				/* -> [ ... trap handler ] */
				DUK_DDD(DUK_DDDPRINT("-> proxy object 'set' for key %!T", (duk_tval *) tv_key));
				DUK_STATS_INC(thr->heap, stats_putprop_proxy);
				duk_push_hobject(thr, h_target);  /* target */
				duk_push_tval(thr, tv_key);       /* P */
				duk_push_tval(thr, tv_val);       /* V */
				duk_push_tval(thr, tv_obj);       /* Receiver: Proxy object */
				duk_call_method(thr, 4 /*nargs*/);
				tmp_bool = duk_to_boolean_top_pop(thr);
				if (!tmp_bool) {
					goto fail_proxy_rejected;
				}

				/* Target object must be checked for a conflicting
				 * non-configurable property.
				 */
				arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
				DUK_ASSERT(key != NULL);

				if (duk__get_own_propdesc_raw(thr, h_target, key, arr_idx, &desc, DUK_GETDESC_FLAG_PUSH_VALUE)) {
					duk_tval *tv_targ = duk_require_tval(thr, -1);
					duk_bool_t datadesc_reject;
					duk_bool_t accdesc_reject;

					DUK_DDD(DUK_DDDPRINT("proxy 'set': target has matching property %!O, check for "
					                     "conflicting property; tv_val=%!T, tv_targ=%!T, desc.flags=0x%08lx, "
					                     "desc.get=%p, desc.set=%p",
					                     (duk_heaphdr *) key, (duk_tval *) tv_val, (duk_tval *) tv_targ,
					                     (unsigned long) desc.flags,
					                     (void *) desc.get, (void *) desc.set));

					datadesc_reject = !(desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) &&
					                  !(desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) &&
					                  !(desc.flags & DUK_PROPDESC_FLAG_WRITABLE) &&
					                  !duk_js_samevalue(tv_val, tv_targ);
					accdesc_reject = (desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) &&
					                 !(desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) &&
					                 (desc.set == NULL);
					if (datadesc_reject || accdesc_reject) {
						DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
						DUK_WO_NORETURN(return 0;);
					}

					duk_pop_2_unsafe(thr);
				} else {
					duk_pop_unsafe(thr);
				}
				return 1;  /* success */
			}

			orig = h_target;  /* resume write to target */
			DUK_TVAL_SET_OBJECT(tv_obj, orig);
		}
#endif  /* DUK_USE_ES6_PROXY */

		curr = orig;
		break;
	}

	case DUK_TAG_BUFFER: {
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv_obj);
		duk_int_t pop_count = 0;

		/*
		 *  Because buffer values may be looped over and read/written
		 *  from, an array index fast path is important.
		 */

#if defined(DUK_USE_FASTINT)
		if (DUK_TVAL_IS_FASTINT(tv_key)) {
			arr_idx = duk__tval_fastint_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a fast-path fastint; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		} else
#endif
		if (DUK_TVAL_IS_NUMBER(tv_key)) {
			arr_idx = duk__tval_number_to_arr_idx(tv_key);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a fast-path number; arr_idx %ld", (long) arr_idx));
			pop_count = 0;
		} else {
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
			pop_count = 1;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HBUFFER_GET_SIZE(h)) {
			duk_uint8_t *data;
			DUK_DDD(DUK_DDDPRINT("writing to buffer data at index %ld", (long) arr_idx));
			data = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h);

			/* XXX: duk_to_int() ensures we'll get 8 lowest bits as
			 * as input is within duk_int_t range (capped outside it).
			 */
#if defined(DUK_USE_FASTINT)
			/* Buffer writes are often integers. */
			if (DUK_TVAL_IS_FASTINT(tv_val)) {
				data[arr_idx] = (duk_uint8_t) DUK_TVAL_GET_FASTINT_U32(tv_val);
			}
			else
#endif
			{
				duk_push_tval(thr, tv_val);
				data[arr_idx] = (duk_uint8_t) duk_to_uint32(thr, -1);
				pop_count++;
			}

			duk_pop_n_unsafe(thr, pop_count);
			DUK_DDD(DUK_DDDPRINT("result: success (buffer data write)"));
			DUK_STATS_INC(thr->heap, stats_putprop_bufferidx);
			return 1;
		}

		if (pop_count == 0) {
			/* This is a pretty awkward control flow, but we need to recheck the
			 * key coercion here.
			 */
			arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
			DUK_ASSERT(key != NULL);
			DUK_DDD(DUK_DDDPRINT("base object buffer, key is a non-fast-path number; after "
			                     "coercion key is %!T, arr_idx %ld",
			                     (duk_tval *) duk_get_tval(thr, -1), (long) arr_idx));
		}

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			goto fail_not_writable;
		}

		DUK_DDD(DUK_DDDPRINT("base object is a buffer, start lookup from Uint8Array prototype"));
		curr = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
		goto lookup;  /* avoid double coercion */
	}

	case DUK_TAG_POINTER: {
		DUK_DDD(DUK_DDDPRINT("base object is a pointer, start lookup from pointer prototype"));
		curr = thr->builtins[DUK_BIDX_POINTER_PROTOTYPE];
		break;
	}

	case DUK_TAG_LIGHTFUNC: {
		/* Lightfuncs have no own properties and are considered non-extensible.
		 * However, the write may be captured by an inherited setter which
		 * means we can't stop the lookup here.
		 */
		DUK_DDD(DUK_DDDPRINT("base object is a lightfunc, start lookup from function prototype"));
		curr = thr->builtins[DUK_BIDX_NATIVE_FUNCTION_PROTOTYPE];
		break;
	}

#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default: {
		/* number */
		DUK_DDD(DUK_DDDPRINT("base object is a number, start lookup from number prototype"));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_obj));
		curr = thr->builtins[DUK_BIDX_NUMBER_PROTOTYPE];
		break;
	}
	}

	DUK_ASSERT(key == NULL);
	arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
	DUK_ASSERT(key != NULL);

 lookup:

	/*
	 *  Check whether the property already exists in the prototype chain.
	 *  Note that the actual write goes into the original base object
	 *  (except if an accessor property captures the write).
	 */

	/* [key] */

	DUK_ASSERT(curr != NULL);
	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (!duk__get_own_propdesc_raw(thr, curr, key, arr_idx, &desc, 0 /*flags*/)) {  /* don't push value */
			goto next_in_chain;
		}

		if (desc.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			/*
			 *  Found existing accessor property (own or inherited).
			 *  Call setter with 'this' set to orig, and value as the only argument.
			 *  Setter calls are OK even for ROM objects.
			 *
			 *  Note: no exotic arguments object behavior, because [[Put]] never
			 *  calls [[DefineOwnProperty]] (E5 Section 8.12.5, step 5.b).
			 */

			duk_hobject *setter;

			DUK_DD(DUK_DDPRINT("put to an own or inherited accessor, calling setter"));

			setter = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, curr, desc.e_idx);
			if (!setter) {
				goto fail_no_setter;
			}
			duk_push_hobject(thr, setter);
			duk_push_tval(thr, tv_obj);  /* note: original, uncoerced base */
			duk_push_tval(thr, tv_val);  /* [key setter this val] */
#if defined(DUK_USE_NONSTD_SETTER_KEY_ARGUMENT)
			duk_dup_m4(thr);
			duk_call_method(thr, 2);     /* [key setter this val key] -> [key retval] */
#else
			duk_call_method(thr, 1);     /* [key setter this val] -> [key retval] */
#endif
			duk_pop_unsafe(thr);         /* ignore retval -> [key] */
			goto success_no_arguments_exotic;
		}

		if (orig == NULL) {
			/*
			 *  Found existing own or inherited plain property, but original
			 *  base is a primitive value.
			 */
			DUK_DD(DUK_DDPRINT("attempt to create a new property in a primitive base object"));
			goto fail_base_primitive;
		}

		if (curr != orig) {
			/*
			 *  Found existing inherited plain property.
			 *  Do an access control check, and if OK, write
			 *  new property to 'orig'.
			 */
			if (!DUK_HOBJECT_HAS_EXTENSIBLE(orig)) {
				DUK_DD(DUK_DDPRINT("found existing inherited plain property, but original object is not extensible"));
				goto fail_not_extensible;
			}
			if (!(desc.flags & DUK_PROPDESC_FLAG_WRITABLE)) {
				DUK_DD(DUK_DDPRINT("found existing inherited plain property, original object is extensible, but inherited property is not writable"));
				goto fail_not_writable;
			}
			DUK_DD(DUK_DDPRINT("put to new property, object extensible, inherited property found and is writable"));
			goto create_new;
		} else {
			/*
			 *  Found existing own (non-inherited) plain property.
			 *  Do an access control check and update in place.
			 */

			if (!(desc.flags & DUK_PROPDESC_FLAG_WRITABLE)) {
				DUK_DD(DUK_DDPRINT("found existing own (non-inherited) plain property, but property is not writable"));
				goto fail_not_writable;
			}
			if (desc.flags & DUK_PROPDESC_FLAG_VIRTUAL) {
				DUK_DD(DUK_DDPRINT("found existing own (non-inherited) virtual property, property is writable"));

				if (DUK_HOBJECT_IS_ARRAY(curr)) {
					/*
					 *  Write to 'length' of an array is a very complex case
					 *  handled in a helper which updates both the array elements
					 *  and writes the new 'length'.  The write may result in an
					 *  unconditional RangeError or a partial write (indicated
					 *  by a return code).
					 *
					 *  Note: the helper has an unnecessary writability check
					 *  for 'length', we already know it is writable.
					 */
					DUK_ASSERT(key == DUK_HTHREAD_STRING_LENGTH(thr));  /* only virtual array property */

					DUK_DDD(DUK_DDDPRINT("writing existing 'length' property to array exotic, invoke complex helper"));

					/* XXX: the helper currently assumes stack top contains new
					 * 'length' value and the whole calling convention is not very
					 * compatible with what we need.
					 */

					duk_push_tval(thr, tv_val);  /* [key val] */
					rc = duk__handle_put_array_length(thr, orig);
					duk_pop_unsafe(thr);  /* [key val] -> [key] */
					if (!rc) {
						goto fail_array_length_partial;
					}

					/* key is 'length', cannot match argument exotic behavior */
					goto success_no_arguments_exotic;
				}
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
				else if (DUK_HOBJECT_IS_BUFOBJ(curr)) {
					duk_hbufobj *h_bufobj;
					duk_uint_t byte_off;
					duk_small_uint_t elem_size;

					h_bufobj = (duk_hbufobj *) curr;
					DUK_HBUFOBJ_ASSERT_VALID(h_bufobj);

					DUK_DD(DUK_DDPRINT("writable virtual property is in buffer object"));

					/* Careful with wrapping: arr_idx upshift may easily wrap, whereas
					 * length downshift won't.
					 */
					if (arr_idx < (h_bufobj->length >> h_bufobj->shift) && DUK_HBUFOBJ_HAS_VIRTUAL_INDICES(h_bufobj)) {
						duk_uint8_t *data;
						DUK_DDD(DUK_DDDPRINT("writing to buffer data at index %ld", (long) arr_idx));

						DUK_ASSERT(arr_idx != DUK__NO_ARRAY_INDEX);  /* index/length check guarantees */
						byte_off = arr_idx << h_bufobj->shift;       /* no wrap assuming h_bufobj->length is valid */
						elem_size = (duk_small_uint_t) (1U << h_bufobj->shift);

						/* Coerce to number before validating pointers etc so that the
						 * number coercions in duk_hbufobj_validated_write() are
						 * guaranteed to be side effect free and not invalidate the
						 * pointer checks we do here.
						 */
						duk_push_tval(thr, tv_val);
						(void) duk_to_number_m1(thr);

						if (h_bufobj->buf != NULL && DUK_HBUFOBJ_VALID_BYTEOFFSET_EXCL(h_bufobj, byte_off + elem_size)) {
							data = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_bufobj->buf) + h_bufobj->offset + byte_off;
							duk_hbufobj_validated_write(thr, h_bufobj, data, elem_size);
						} else {
							DUK_D(DUK_DPRINT("bufobj access out of underlying buffer, ignoring (write skipped)"));
						}
						duk_pop_unsafe(thr);
						goto success_no_arguments_exotic;
					}
				}
#endif  /* DUK_USE_BUFFEROBJECT_SUPPORT */

				DUK_D(DUK_DPRINT("should not happen, key %!O", key));
				goto fail_internal;  /* should not happen */
			}
			DUK_DD(DUK_DDPRINT("put to existing own plain property, property is writable"));
			goto update_old;
		}
		DUK_UNREACHABLE();

	 next_in_chain:
		/* XXX: option to pretend property doesn't exist if sanity limit is
		 * hit might be useful.
		 */
		if (DUK_UNLIKELY(sanity-- == 0)) {
			DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
			DUK_WO_NORETURN(return 0;);
		}
		curr = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, curr);
	} while (curr != NULL);

	/*
	 *  Property not found in prototype chain.
	 */

	DUK_DDD(DUK_DDDPRINT("property not found in prototype chain"));

	if (orig == NULL) {
		DUK_DD(DUK_DDPRINT("attempt to create a new property in a primitive base object"));
		goto fail_base_primitive;
	}

	if (!DUK_HOBJECT_HAS_EXTENSIBLE(orig)) {
		DUK_DD(DUK_DDPRINT("put to a new property (not found in prototype chain), but original object not extensible"));
		goto fail_not_extensible;
	}

	goto create_new;

 update_old:

	/*
	 *  Update an existing property of the base object.
	 */

	/* [key] */

	DUK_DDD(DUK_DDDPRINT("update an existing property of the original object"));

	DUK_ASSERT(orig != NULL);
#if defined(DUK_USE_ROM_OBJECTS)
	/* This should not happen because DUK_TAG_OBJECT case checks
	 * for this already, but check just in case.
	 */
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) orig)) {
		goto fail_not_writable;
	}
#endif

	/* Although there are writable virtual properties (e.g. plain buffer
	 * and buffer object number indices), they are handled before we come
	 * here.
	 */
	DUK_ASSERT((desc.flags & DUK_PROPDESC_FLAG_VIRTUAL) == 0);
	DUK_ASSERT(desc.a_idx >= 0 || desc.e_idx >= 0);

	/* Array own property .length is handled above. */
	DUK_ASSERT(!(DUK_HOBJECT_IS_ARRAY(orig) && key == DUK_HTHREAD_STRING_LENGTH(thr)));

	if (desc.e_idx >= 0) {
		tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, orig, desc.e_idx);
		DUK_DDD(DUK_DDDPRINT("previous entry value: %!iT", (duk_tval *) tv));
		DUK_TVAL_SET_TVAL_UPDREF(thr, tv, tv_val);  /* side effects; e_idx may be invalidated */
		/* don't touch property attributes or hash part */
		DUK_DD(DUK_DDPRINT("put to an existing entry at index %ld -> new value %!iT",
		                   (long) desc.e_idx, (duk_tval *) tv));
	} else {
		/* Note: array entries are always writable, so the writability check
		 * above is pointless for them.  The check could be avoided with some
		 * refactoring but is probably not worth it.
		 */

		DUK_ASSERT(desc.a_idx >= 0);
		tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, orig, desc.a_idx);
		DUK_DDD(DUK_DDDPRINT("previous array value: %!iT", (duk_tval *) tv));
		DUK_TVAL_SET_TVAL_UPDREF(thr, tv, tv_val);  /* side effects; a_idx may be invalidated */
		DUK_DD(DUK_DDPRINT("put to an existing array entry at index %ld -> new value %!iT",
		                   (long) desc.a_idx, (duk_tval *) tv));
	}

	/* Regardless of whether property is found in entry or array part,
	 * it may have arguments exotic behavior (array indices may reside
	 * in entry part for abandoned / non-existent array parts).
	 */
	goto success_with_arguments_exotic;

 create_new:

	/*
	 *  Create a new property in the original object.
	 *
	 *  Exotic properties need to be reconsidered here from a write
	 *  perspective (not just property attributes perspective).
	 *  However, the property does not exist in the object already,
	 *  so this limits the kind of exotic properties that apply.
	 */

	/* [key] */

	DUK_DDD(DUK_DDDPRINT("create new property to original object"));

	DUK_ASSERT(orig != NULL);

	/* Array own property .length is handled above. */
	DUK_ASSERT(!(DUK_HOBJECT_IS_ARRAY(orig) && key == DUK_HTHREAD_STRING_LENGTH(thr)));

#if defined(DUK_USE_ROM_OBJECTS)
	/* This should not happen because DUK_TAG_OBJECT case checks
	 * for this already, but check just in case.
	 */
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) orig)) {
		goto fail_not_writable;
	}
#endif

	/* Not possible because array object 'length' is present
	 * from its creation and cannot be deleted, and is thus
	 * caught as an existing property above.
	 */
	DUK_ASSERT(!(DUK_HOBJECT_HAS_EXOTIC_ARRAY(orig) &&
	             key == DUK_HTHREAD_STRING_LENGTH(thr)));

	if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(orig) &&
	    arr_idx != DUK__NO_ARRAY_INDEX) {
		/* automatic length update */
		duk_uint32_t old_len;
		duk_harray *a;

		a = (duk_harray *) orig;
		DUK_HARRAY_ASSERT_VALID(a);

		old_len = a->length;

		if (arr_idx >= old_len) {
			DUK_DDD(DUK_DDDPRINT("write new array entry requires length update "
			                     "(arr_idx=%ld, old_len=%ld)",
			                     (long) arr_idx, (long) old_len));

			if (DUK_HARRAY_LENGTH_NONWRITABLE(a)) {
				DUK_DD(DUK_DDPRINT("attempt to extend array, but array 'length' is not writable"));
				goto fail_not_writable;
			}

			/* Note: actual update happens once write has been completed
			 * without error below.  The write should always succeed
			 * from a specification viewpoint, but we may e.g. run out
			 * of memory.  It's safer in this order.
			 */

			DUK_ASSERT(arr_idx != 0xffffffffUL);
			new_array_length = arr_idx + 1;  /* flag for later write */
		} else {
			DUK_DDD(DUK_DDDPRINT("write new array entry does not require length update "
			                     "(arr_idx=%ld, old_len=%ld)",
			                     (long) arr_idx, (long) old_len));
		}
	}

 /* write_to_array_part: */

	/*
	 *  Write to array part?
	 *
	 *  Note: array abandonding requires a property resize which uses
	 *  'rechecks' valstack for temporaries and may cause any existing
	 *  valstack pointers to be invalidated.  To protect against this,
	 *  tv_obj, tv_key, and tv_val are copies of the original inputs.
	 */

	if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HOBJECT_HAS_ARRAY_PART(orig)) {
		tv = duk__obtain_arridx_slot(thr, arr_idx, orig);
		if (tv == NULL) {
			DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(orig));
			goto write_to_entry_part;
		}

		/* prev value must be unused, no decref */
		DUK_ASSERT(DUK_TVAL_IS_UNUSED(tv));
		DUK_TVAL_SET_TVAL(tv, tv_val);
		DUK_TVAL_INCREF(thr, tv);
		DUK_DD(DUK_DDPRINT("put to new array entry: %ld -> %!T",
		                   (long) arr_idx, (duk_tval *) tv));

		/* Note: array part values are [[Writable]], [[Enumerable]],
		 * and [[Configurable]] which matches the required attributes
		 * here.
		 */
		goto entry_updated;
	}

 write_to_entry_part:

	/*
	 *  Write to entry part
	 */

	/* entry allocation updates hash part and increases the key
	 * refcount; may need a props allocation resize but doesn't
	 * 'recheck' the valstack.
	 */
	e_idx = duk__hobject_alloc_entry_checked(thr, orig, key);
	DUK_ASSERT(e_idx >= 0);

	tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, orig, e_idx);
	/* prev value can be garbage, no decref */
	DUK_TVAL_SET_TVAL(tv, tv_val);
	DUK_TVAL_INCREF(thr, tv);
	DUK_HOBJECT_E_SET_FLAGS(thr->heap, orig, e_idx, DUK_PROPDESC_FLAGS_WEC);
	goto entry_updated;

 entry_updated:

	/*
	 *  Possible pending array length update, which must only be done
	 *  if the actual entry write succeeded.
	 */

	if (new_array_length > 0) {
		/* Note: zero works as a "no update" marker because the new length
		 * can never be zero after a new property is written.
		 */

		DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY(orig));

		DUK_DDD(DUK_DDDPRINT("write successful, pending array length update to: %ld",
		                     (long) new_array_length));

		((duk_harray *) orig)->length = new_array_length;
	}

	/*
	 *  Arguments exotic behavior not possible for new properties: all
	 *  magically bound properties are initially present in the arguments
	 *  object, and if they are deleted, the binding is also removed from
	 *  parameter map.
	 */

	goto success_no_arguments_exotic;

 success_with_arguments_exotic:

	/*
	 *  Arguments objects have exotic [[DefineOwnProperty]] which updates
	 *  the internal 'map' of arguments for writes to currently mapped
	 *  arguments.  More conretely, writes to mapped arguments generate
	 *  a write to a bound variable.
	 *
	 *  The [[Put]] algorithm invokes [[DefineOwnProperty]] for existing
	 *  data properties and new properties, but not for existing accessors.
	 *  Hence, in E5 Section 10.6 ([[DefinedOwnProperty]] algorithm), we
	 *  have a Desc with 'Value' (and possibly other properties too), and
	 *  we end up in step 5.b.i.
	 */

	if (arr_idx != DUK__NO_ARRAY_INDEX &&
	    DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(orig)) {
		/* Note: only numbered indices are relevant, so arr_idx fast reject
		 * is good (this is valid unless there are more than 4**32-1 arguments).
		 */

		DUK_DDD(DUK_DDDPRINT("putprop successful, arguments exotic behavior needed"));

		/* Note: we can reuse 'desc' here */

		/* XXX: top of stack must contain value, which helper doesn't touch,
		 * rework to use tv_val directly?
		 */

		duk_push_tval(thr, tv_val);
		(void) duk__check_arguments_map_for_put(thr, orig, key, &desc, throw_flag);
		duk_pop_unsafe(thr);
	}
	/* fall thru */

 success_no_arguments_exotic:
	/* shared exit path now */
	DUK_DDD(DUK_DDDPRINT("result: success"));
	duk_pop_unsafe(thr);  /* remove key */
	return 1;

#if defined(DUK_USE_ES6_PROXY)
 fail_proxy_rejected:
	DUK_DDD(DUK_DDDPRINT("result: error, proxy rejects"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
		DUK_WO_NORETURN(return 0;);
	}
	/* Note: no key on stack */
	return 0;
#endif

 fail_base_primitive:
	DUK_DDD(DUK_DDDPRINT("result: error, base primitive"));
	if (throw_flag) {
#if defined(DUK_USE_PARANOID_ERRORS)
		DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BASE);
#else
		DUK_ERROR_FMT2(thr, DUK_ERR_TYPE_ERROR, "cannot write property %s of %s",
		               duk_push_string_tval_readable(thr, tv_key), duk_push_string_tval_readable(thr, tv_obj));
#endif
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;

 fail_not_extensible:
	DUK_DDD(DUK_DDDPRINT("result: error, not extensible"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_EXTENSIBLE);
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;

 fail_not_writable:
	DUK_DDD(DUK_DDDPRINT("result: error, not writable"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_WRITABLE);
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;

#if defined(DUK_USE_ROM_OBJECTS)
 fail_not_writable_no_pop:
	DUK_DDD(DUK_DDDPRINT("result: error, not writable"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_WRITABLE);
		DUK_WO_NORETURN(return 0;);
	}
	return 0;
#endif

 fail_array_length_partial:
	DUK_DD(DUK_DDPRINT("result: error, array length write only partially successful"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;

 fail_no_setter:
	DUK_DDD(DUK_DDDPRINT("result: error, accessor property without setter"));
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_SETTER_UNDEFINED);
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;

 fail_internal:
	DUK_DDD(DUK_DDDPRINT("result: error, internal"));
	if (throw_flag) {
		DUK_ERROR_INTERNAL(thr);
		DUK_WO_NORETURN(return 0;);
	}
	duk_pop_unsafe(thr);  /* remove key */
	return 0;
}

/*
 *  ECMAScript compliant [[Delete]](P, Throw).
 */

DUK_INTERNAL duk_bool_t duk_hobject_delprop_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_small_uint_t flags) {
	duk_propdesc desc;
	duk_tval *tv;
	duk_uint32_t arr_idx;
	duk_bool_t throw_flag;
	duk_bool_t force_flag;

	throw_flag = (flags & DUK_DELPROP_FLAG_THROW);
	force_flag = (flags & DUK_DELPROP_FLAG_FORCE);

	DUK_DDD(DUK_DDDPRINT("delprop_raw: thr=%p, obj=%p, key=%p, throw=%ld, force=%ld (obj -> %!O, key -> %!O)",
	                     (void *) thr, (void *) obj, (void *) key, (long) throw_flag, (long) force_flag,
	                     (duk_heaphdr *) obj, (duk_heaphdr *) key));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	arr_idx = DUK_HSTRING_GET_ARRIDX_FAST(key);

	/* 0 = don't push current value */
	if (!duk__get_own_propdesc_raw(thr, obj, key, arr_idx, &desc, 0 /*flags*/)) {  /* don't push value */
		DUK_DDD(DUK_DDDPRINT("property not found, succeed always"));
		goto success;
	}

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_DD(DUK_DDPRINT("attempt to delprop on read-only target object"));
		goto fail_not_configurable;
	}
#endif

	if ((desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) == 0 && !force_flag) {
		goto fail_not_configurable;
	}
	if (desc.a_idx < 0 && desc.e_idx < 0) {
		/* Currently there are no deletable virtual properties, but
		 * with force_flag we might attempt to delete one.
		 */
		DUK_DD(DUK_DDPRINT("delete failed: property found, force flag, but virtual (and implicitly non-configurable)"));
		goto fail_virtual;
	}

	if (desc.a_idx >= 0) {
		DUK_ASSERT(desc.e_idx < 0);

		tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, desc.a_idx);
		DUK_TVAL_SET_UNUSED_UPDREF(thr, tv);  /* side effects */
		goto success;
	} else {
		DUK_ASSERT(desc.a_idx < 0);

		/* remove hash entry (no decref) */
#if defined(DUK_USE_HOBJECT_HASH_PART)
		if (desc.h_idx >= 0) {
			duk_uint32_t *h_base = DUK_HOBJECT_H_GET_BASE(thr->heap, obj);

			DUK_DDD(DUK_DDDPRINT("removing hash entry at h_idx %ld", (long) desc.h_idx));
			DUK_ASSERT(DUK_HOBJECT_GET_HSIZE(obj) > 0);
			DUK_ASSERT((duk_uint32_t) desc.h_idx < DUK_HOBJECT_GET_HSIZE(obj));
			h_base[desc.h_idx] = DUK__HASH_DELETED;
		} else {
			DUK_ASSERT(DUK_HOBJECT_GET_HSIZE(obj) == 0);
		}
#else
		DUK_ASSERT(DUK_HOBJECT_GET_HSIZE(obj) == 0);
#endif

		/* Remove value.  This requires multiple writes so avoid side
		 * effects via no-refzero macros so that e_idx is not
		 * invalidated.
		 */
		DUK_DDD(DUK_DDDPRINT("before removing value, e_idx %ld, key %p, key at slot %p",
		                     (long) desc.e_idx, (void *) key, (void *) DUK_HOBJECT_E_GET_KEY(thr->heap, obj, desc.e_idx)));
		DUK_DDD(DUK_DDDPRINT("removing value at e_idx %ld", (long) desc.e_idx));
		if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, desc.e_idx)) {
			duk_hobject *tmp;

			tmp = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, obj, desc.e_idx);
			DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, obj, desc.e_idx, NULL);
			DUK_UNREF(tmp);
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, tmp);

			tmp = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, obj, desc.e_idx);
			DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, obj, desc.e_idx, NULL);
			DUK_UNREF(tmp);
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, tmp);
		} else {
			tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, desc.e_idx);
			DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, tv);
		}
#if 0
		/* Not strictly necessary because if key == NULL, flag MUST be ignored. */
		DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, desc.e_idx, 0);
#endif

		/* Remove key. */
		DUK_DDD(DUK_DDDPRINT("before removing key, e_idx %ld, key %p, key at slot %p",
		                     (long) desc.e_idx, (void *) key, (void *) DUK_HOBJECT_E_GET_KEY(thr->heap, obj, desc.e_idx)));
		DUK_DDD(DUK_DDDPRINT("removing key at e_idx %ld", (long) desc.e_idx));
		DUK_ASSERT(key == DUK_HOBJECT_E_GET_KEY(thr->heap, obj, desc.e_idx));
		DUK_HOBJECT_E_SET_KEY(thr->heap, obj, desc.e_idx, NULL);
		DUK_HSTRING_DECREF_NORZ(thr, key);

		/* Trigger refzero side effects only when we're done as a
		 * finalizer might operate on the object and affect the
		 * e_idx we're supposed to use.
		 */
		DUK_REFZERO_CHECK_SLOW(thr);
		goto success;
	}

	DUK_UNREACHABLE();

 success:
	/*
	 *  Argument exotic [[Delete]] behavior (E5 Section 10.6) is
	 *  a post-check, keeping arguments internal 'map' in sync with
	 *  any successful deletes (note that property does not need to
	 *  exist for delete to 'succeed').
	 *
	 *  Delete key from 'map'.  Since 'map' only contains array index
	 *  keys, we can use arr_idx for a fast skip.
	 */

	DUK_DDD(DUK_DDDPRINT("delete successful, check for arguments exotic behavior"));

	if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj)) {
		/* Note: only numbered indices are relevant, so arr_idx fast reject
		 * is good (this is valid unless there are more than 4**32-1 arguments).
		 */

		DUK_DDD(DUK_DDDPRINT("delete successful, arguments exotic behavior needed"));

		/* Note: we can reuse 'desc' here */
		(void) duk__check_arguments_map_for_delete(thr, obj, key, &desc);
	}

	DUK_DDD(DUK_DDDPRINT("delete successful"));
	return 1;

 fail_virtual:  /* just use the same "not configurable" error message */
 fail_not_configurable:
	DUK_DDD(DUK_DDDPRINT("delete failed: property found, not configurable"));

	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);
		DUK_WO_NORETURN(return 0;);
	}
	return 0;
}

/*
 *  DELPROP: ECMAScript property deletion.
 */

DUK_INTERNAL duk_bool_t duk_hobject_delprop(duk_hthread *thr, duk_tval *tv_obj, duk_tval *tv_key, duk_bool_t throw_flag) {
	duk_hstring *key = NULL;
#if defined(DUK_USE_ES6_PROXY)
	duk_propdesc desc;
#endif
	duk_int_t entry_top;
	duk_uint32_t arr_idx = DUK__NO_ARRAY_INDEX;
	duk_bool_t rc;

	DUK_DDD(DUK_DDDPRINT("delprop: thr=%p, obj=%p, key=%p (obj -> %!T, key -> %!T)",
	                     (void *) thr, (void *) tv_obj, (void *) tv_key,
	                     (duk_tval *) tv_obj, (duk_tval *) tv_key));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(tv_obj != NULL);
	DUK_ASSERT(tv_key != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	/* Storing the entry top is cheaper here to ensure stack is correct at exit,
	 * as there are several paths out.
	 */
	entry_top = duk_get_top(thr);

	if (DUK_TVAL_IS_UNDEFINED(tv_obj) ||
	    DUK_TVAL_IS_NULL(tv_obj)) {
		DUK_DDD(DUK_DDDPRINT("base object is undefined or null -> reject"));
		goto fail_invalid_base_uncond;
	}

	duk_push_tval(thr, tv_obj);
	duk_push_tval(thr, tv_key);

	tv_obj = DUK_GET_TVAL_NEGIDX(thr, -2);
	if (DUK_TVAL_IS_OBJECT(tv_obj)) {
		duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv_obj);
		DUK_ASSERT(obj != NULL);

#if defined(DUK_USE_ES6_PROXY)
		if (DUK_UNLIKELY(DUK_HOBJECT_IS_PROXY(obj))) {
			duk_hobject *h_target;
			duk_bool_t tmp_bool;

			/* Note: proxy handling must happen before key is string coerced. */

			if (duk__proxy_check_prop(thr, obj, DUK_STRIDX_DELETE_PROPERTY, tv_key, &h_target)) {
				/* -> [ ... obj key trap handler ] */
				DUK_DDD(DUK_DDDPRINT("-> proxy object 'deleteProperty' for key %!T", (duk_tval *) tv_key));
				duk_push_hobject(thr, h_target);  /* target */
				duk_dup_m4(thr);  /* P */
				duk_call_method(thr, 2 /*nargs*/);
				tmp_bool = duk_to_boolean_top_pop(thr);
				if (!tmp_bool) {
					goto fail_proxy_rejected;  /* retval indicates delete failed */
				}

				/* Target object must be checked for a conflicting
				 * non-configurable property.
				 */
				tv_key = DUK_GET_TVAL_NEGIDX(thr, -1);
				arr_idx = duk__push_tval_to_property_key(thr, tv_key, &key);
				DUK_ASSERT(key != NULL);

				if (duk__get_own_propdesc_raw(thr, h_target, key, arr_idx, &desc, 0 /*flags*/)) {  /* don't push value */
					duk_small_int_t desc_reject;

					DUK_DDD(DUK_DDDPRINT("proxy 'deleteProperty': target has matching property %!O, check for "
					                     "conflicting property; desc.flags=0x%08lx, "
					                     "desc.get=%p, desc.set=%p",
					                     (duk_heaphdr *) key, (unsigned long) desc.flags,
					                     (void *) desc.get, (void *) desc.set));

					desc_reject = !(desc.flags & DUK_PROPDESC_FLAG_CONFIGURABLE);
					if (desc_reject) {
						/* unconditional */
						DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
						DUK_WO_NORETURN(return 0;);
					}
				}
				rc = 1;  /* success */
				goto done_rc;
			}

			obj = h_target;  /* resume delete to target */
		}
#endif  /* DUK_USE_ES6_PROXY */

		arr_idx = duk__to_property_key(thr, -1, &key);
		DUK_ASSERT(key != NULL);

		rc = duk_hobject_delprop_raw(thr, obj, key, throw_flag ? DUK_DELPROP_FLAG_THROW : 0);
		goto done_rc;
	} else if (DUK_TVAL_IS_STRING(tv_obj)) {
		/* String has .length and array index virtual properties
		 * which can't be deleted.  No need for a symbol check;
		 * no offending virtual symbols exist.
		 */
		/* XXX: unnecessary string coercion for array indices,
		 * intentional to keep small.
		 */
		duk_hstring *h = DUK_TVAL_GET_STRING(tv_obj);
		DUK_ASSERT(h != NULL);

		arr_idx = duk__to_property_key(thr, -1, &key);
		DUK_ASSERT(key != NULL);

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			goto fail_not_configurable;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HSTRING_GET_CHARLEN(h)) {
			goto fail_not_configurable;
		}
	} else if (DUK_TVAL_IS_BUFFER(tv_obj)) {
		/* XXX: unnecessary string coercion for array indices,
		 * intentional to keep small; some overlap with string
		 * handling.
		 */
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv_obj);
		DUK_ASSERT(h != NULL);

		arr_idx = duk__to_property_key(thr, -1, &key);
		DUK_ASSERT(key != NULL);

		if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
			goto fail_not_configurable;
		}

		if (arr_idx != DUK__NO_ARRAY_INDEX &&
		    arr_idx < DUK_HBUFFER_GET_SIZE(h)) {
			goto fail_not_configurable;
		}
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv_obj)) {
		/* Lightfunc has no virtual properties since Duktape 2.2
		 * so success.  Still must coerce key for side effects.
		 */

		arr_idx = duk__to_property_key(thr, -1, &key);
		DUK_ASSERT(key != NULL);
		DUK_UNREF(key);
	}

	/* non-object base, no offending virtual property */
	rc = 1;
	goto done_rc;

 done_rc:
	duk_set_top_unsafe(thr, entry_top);
	return rc;

 fail_invalid_base_uncond:
	/* Note: unconditional throw */
	DUK_ASSERT(duk_get_top(thr) == entry_top);
#if defined(DUK_USE_PARANOID_ERRORS)
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_BASE);
#else
	DUK_ERROR_FMT2(thr, DUK_ERR_TYPE_ERROR, "cannot delete property %s of %s",
	               duk_push_string_tval_readable(thr, tv_key), duk_push_string_tval_readable(thr, tv_obj));
#endif
	DUK_WO_NORETURN(return 0;);

#if defined(DUK_USE_ES6_PROXY)
 fail_proxy_rejected:
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_PROXY_REJECTED);
		DUK_WO_NORETURN(return 0;);
	}
	duk_set_top_unsafe(thr, entry_top);
	return 0;
#endif

 fail_not_configurable:
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);
		DUK_WO_NORETURN(return 0;);
	}
	duk_set_top_unsafe(thr, entry_top);
	return 0;
}

/*
 *  Internal helper to define a property with specific flags, ignoring
 *  normal semantics such as extensibility, write protection etc.
 *  Overwrites any existing value and attributes unless caller requests
 *  that value only be updated if it doesn't already exists.
 *
 *  Does not support:
 *    - virtual properties (error if write attempted)
 *    - getter/setter properties (error if write attempted)
 *    - non-default (!= WEC) attributes for array entries (error if attempted)
 *    - array abandoning: if array part exists, it is always extended
 *    - array 'length' updating
 *
 *  Stack: [... in_val] -> []
 *
 *  Used for e.g. built-in initialization and environment record
 *  operations.
 */

DUK_INTERNAL void duk_hobject_define_property_internal(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_small_uint_t flags) {
	duk_propdesc desc;
	duk_uint32_t arr_idx;
	duk_int_t e_idx;
	duk_tval *tv1 = NULL;
	duk_tval *tv2 = NULL;
	duk_small_uint_t propflags = flags & DUK_PROPDESC_FLAGS_MASK;  /* mask out flags not actually stored */

	DUK_DDD(DUK_DDDPRINT("define new property (internal): thr=%p, obj=%!O, key=%!O, flags=0x%02lx, val=%!T",
	                     (void *) thr, (duk_heaphdr *) obj, (duk_heaphdr *) key,
	                     (unsigned long) flags, (duk_tval *) duk_get_tval(thr, -1)));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));
	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);
	DUK_ASSERT(duk_is_valid_index(thr, -1));  /* contains value */

	arr_idx = DUK_HSTRING_GET_ARRIDX_SLOW(key);

	if (duk__get_own_propdesc_raw(thr, obj, key, arr_idx, &desc, 0 /*flags*/)) {  /* don't push value */
		if (desc.e_idx >= 0) {
			if (flags & DUK_PROPDESC_FLAG_NO_OVERWRITE) {
				DUK_DDD(DUK_DDDPRINT("property already exists in the entry part -> skip as requested"));
				goto pop_exit;
			}
			DUK_DDD(DUK_DDDPRINT("property already exists in the entry part -> update value and attributes"));
			if (DUK_UNLIKELY(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, desc.e_idx))) {
				DUK_D(DUK_DPRINT("existing property is an accessor, not supported"));
				goto error_internal;
			}

			DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, desc.e_idx, propflags);
			tv1 = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, desc.e_idx);
		} else if (desc.a_idx >= 0) {
			if (flags & DUK_PROPDESC_FLAG_NO_OVERWRITE) {
				DUK_DDD(DUK_DDDPRINT("property already exists in the array part -> skip as requested"));
				goto pop_exit;
			}
			DUK_DDD(DUK_DDDPRINT("property already exists in the array part -> update value (assert attributes)"));
			if (propflags != DUK_PROPDESC_FLAGS_WEC) {
				DUK_D(DUK_DPRINT("existing property in array part, but propflags not WEC (0x%02lx)",
				                 (unsigned long) propflags));
				goto error_internal;
			}

			tv1 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, desc.a_idx);
		} else {
			if (flags & DUK_PROPDESC_FLAG_NO_OVERWRITE) {
				DUK_DDD(DUK_DDDPRINT("property already exists but is virtual -> skip as requested"));
				goto pop_exit;
			}
			if (key == DUK_HTHREAD_STRING_LENGTH(thr) && DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
				duk_uint32_t new_len;
#if defined(DUK_USE_DEBUG)
				duk_uint32_t prev_len;
				prev_len = ((duk_harray *) obj)->length;
#endif
				new_len = duk__to_new_array_length_checked(thr, DUK_GET_TVAL_NEGIDX(thr, -1));
				((duk_harray *) obj)->length = new_len;
				DUK_DD(DUK_DDPRINT("internal define property for array .length: %ld -> %ld",
				                   (long) prev_len, (long) ((duk_harray *) obj)->length));
				goto pop_exit;
			}
			DUK_DD(DUK_DDPRINT("property already exists but is virtual -> failure"));
			goto error_virtual;
		}

		goto write_value;
	}

	if (DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
		if (arr_idx != DUK__NO_ARRAY_INDEX) {
			DUK_DDD(DUK_DDDPRINT("property does not exist, object has array part -> possibly extend array part and write value (assert attributes)"));
			DUK_ASSERT(propflags == DUK_PROPDESC_FLAGS_WEC);

			tv1 = duk__obtain_arridx_slot(thr, arr_idx, obj);
			if (tv1 == NULL) {
				DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(obj));
				goto write_to_entry_part;
			}

			tv1 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
			goto write_value;
		}
	}

 write_to_entry_part:
	DUK_DDD(DUK_DDDPRINT("property does not exist, object belongs in entry part -> allocate new entry and write value and attributes"));
	e_idx = duk__hobject_alloc_entry_checked(thr, obj, key);  /* increases key refcount */
	DUK_ASSERT(e_idx >= 0);
	DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, e_idx, propflags);
	tv1 = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, e_idx);
	/* new entry: previous value is garbage; set to undefined to share write_value */
	DUK_TVAL_SET_UNDEFINED(tv1);
	goto write_value;

 write_value:
	/* tv1 points to value storage */

	tv2 = duk_require_tval(thr, -1);  /* late lookup, avoid side effects */
	DUK_DDD(DUK_DDDPRINT("writing/updating value: %!T -> %!T",
	                     (duk_tval *) tv1, (duk_tval *) tv2));

	DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects */
	goto pop_exit;

 pop_exit:
	duk_pop_unsafe(thr);  /* remove in_val */
	return;

 error_virtual:  /* share error message */
 error_internal:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return;);
}

/*
 *  Fast path for defining array indexed values without interning the key.
 *  This is used by e.g. code for Array prototype and traceback creation so
 *  must avoid interning.
 */

DUK_INTERNAL void duk_hobject_define_property_internal_arridx(duk_hthread *thr, duk_hobject *obj, duk_uarridx_t arr_idx, duk_small_uint_t flags) {
	duk_hstring *key;
	duk_tval *tv1, *tv2;

	DUK_DDD(DUK_DDDPRINT("define new property (internal) arr_idx fast path: thr=%p, obj=%!O, "
	                     "arr_idx=%ld, flags=0x%02lx, val=%!T",
	                     (void *) thr, obj, (long) arr_idx, (unsigned long) flags,
	                     (duk_tval *) duk_get_tval(thr, -1)));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));

	if (DUK_HOBJECT_HAS_ARRAY_PART(obj) &&
	    arr_idx != DUK__NO_ARRAY_INDEX &&
	    flags == DUK_PROPDESC_FLAGS_WEC) {
		DUK_ASSERT((flags & DUK_PROPDESC_FLAG_NO_OVERWRITE) == 0);  /* covered by comparison */

		DUK_DDD(DUK_DDDPRINT("define property to array part (property may or may not exist yet)"));

		tv1 = duk__obtain_arridx_slot(thr, arr_idx, obj);
		if (tv1 == NULL) {
			DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(obj));
			goto write_slow;
		}
		tv2 = duk_require_tval(thr, -1);

		DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects */

		duk_pop_unsafe(thr);  /* [ ...val ] -> [ ... ] */
		return;
	}

 write_slow:
	DUK_DDD(DUK_DDDPRINT("define property fast path didn't work, use slow path"));

	key = duk_push_uint_to_hstring(thr, (duk_uint_t) arr_idx);
	DUK_ASSERT(key != NULL);
	duk_insert(thr, -2);  /* [ ... val key ] -> [ ... key val ] */

	duk_hobject_define_property_internal(thr, obj, key, flags);

	duk_pop_unsafe(thr);  /* [ ... key ] -> [ ... ] */
}

/*
 *  Internal helpers for managing object 'length'
 */

DUK_INTERNAL duk_size_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj) {
	duk_double_t val;

	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(obj != NULL);

	/* Fast path for Arrays. */
	if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
		return ((duk_harray *) obj)->length;
	}

	/* Slow path, .length can be e.g. accessor, obj can be a Proxy, etc. */
	duk_push_hobject(thr, obj);
	duk_push_hstring_stridx(thr, DUK_STRIDX_LENGTH);
	(void) duk_hobject_getprop(thr,
	                           DUK_GET_TVAL_NEGIDX(thr, -2),
	                           DUK_GET_TVAL_NEGIDX(thr, -1));
	val = duk_to_number_m1(thr);
	duk_pop_3_unsafe(thr);

	/* This isn't part of ECMAScript semantics; return a value within
	 * duk_size_t range, or 0 otherwise.
	 */
	if (val >= 0.0 && val <= (duk_double_t) DUK_SIZE_MAX) {
		return (duk_size_t) val;
	}
	return 0;
}

/*
 *  Fast finalizer check for an object.  Walks the prototype chain, checking
 *  for finalizer presence using DUK_HOBJECT_FLAG_HAVE_FINALIZER which is kept
 *  in sync with the actual property when setting/removing the finalizer.
 */

#if defined(DUK_USE_HEAPPTR16)
DUK_INTERNAL duk_bool_t duk_hobject_has_finalizer_fast_raw(duk_heap *heap, duk_hobject *obj) {
#else
DUK_INTERNAL duk_bool_t duk_hobject_has_finalizer_fast_raw(duk_hobject *obj) {
#endif
	duk_uint_t sanity;

	DUK_ASSERT(obj != NULL);

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		if (DUK_UNLIKELY(DUK_HOBJECT_HAS_HAVE_FINALIZER(obj))) {
			return 1;
		}
		if (DUK_UNLIKELY(sanity-- == 0)) {
			DUK_D(DUK_DPRINT("prototype loop when checking for finalizer existence; returning false"));
			return 0;
		}
#if defined(DUK_USE_HEAPPTR16)
		DUK_ASSERT(heap != NULL);
		obj = DUK_HOBJECT_GET_PROTOTYPE(heap, obj);
#else
		obj = DUK_HOBJECT_GET_PROTOTYPE(NULL, obj);  /* 'heap' arg ignored */
#endif
	} while (obj != NULL);

	return 0;
}

/*
 *  Object.getOwnPropertyDescriptor()  (E5 Sections 15.2.3.3, 8.10.4)
 *
 *  [ ... key ] -> [ ... desc/undefined ]
 */

DUK_INTERNAL void duk_hobject_object_get_own_property_descriptor(duk_hthread *thr, duk_idx_t obj_idx) {
	duk_hobject *obj;
	duk_hstring *key;
	duk_propdesc pd;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

	obj = duk_require_hobject_promote_mask(thr, obj_idx, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
	key = duk_to_property_key_hstring(thr, -1);
	DUK_ASSERT(key != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	if (!duk_hobject_get_own_propdesc(thr, obj, key, &pd, DUK_GETDESC_FLAG_PUSH_VALUE)) {
		duk_push_undefined(thr);
		duk_remove_m2(thr);
		return;
	}

	duk_push_object(thr);

	/* [ ... key value desc ] */

	if (DUK_PROPDESC_IS_ACCESSOR(&pd)) {
		/* If a setter/getter is missing (undefined), the descriptor must
		 * still have the property present with the value 'undefined'.
		 */
		if (pd.get) {
			duk_push_hobject(thr, pd.get);
		} else {
			duk_push_undefined(thr);
		}
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_GET);
		if (pd.set) {
			duk_push_hobject(thr, pd.set);
		} else {
			duk_push_undefined(thr);
		}
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_SET);
	} else {
		duk_dup_m2(thr);
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_VALUE);
		duk_push_boolean(thr, DUK_PROPDESC_IS_WRITABLE(&pd));
		duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_WRITABLE);
	}
	duk_push_boolean(thr, DUK_PROPDESC_IS_ENUMERABLE(&pd));
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_ENUMERABLE);
	duk_push_boolean(thr, DUK_PROPDESC_IS_CONFIGURABLE(&pd));
	duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_CONFIGURABLE);

	/* [ ... key value desc ] */

	duk_replace(thr, -3);
	duk_pop_unsafe(thr);  /* -> [ ... desc ] */
}

/*
 *  NormalizePropertyDescriptor() related helper.
 *
 *  Internal helper which validates and normalizes a property descriptor
 *  represented as an ECMAScript object (e.g. argument to defineProperty()).
 *  The output of this conversion is a set of defprop_flags and possibly
 *  some values pushed on the value stack to (1) ensure borrowed pointers
 *  remain valid, and (2) avoid unnecessary pops for footprint reasons.
 *  Caller must manage stack top carefully because the number of values
 *  pushed depends on the input property descriptor.
 *
 *  The original descriptor object must not be altered in the process.
 */

/* XXX: very basic optimization -> duk_get_prop_stridx_top */

DUK_INTERNAL
void duk_hobject_prepare_property_descriptor(duk_hthread *thr,
                                             duk_idx_t idx_in,
                                             duk_uint_t *out_defprop_flags,
                                             duk_idx_t *out_idx_value,
                                             duk_hobject **out_getter,
                                             duk_hobject **out_setter) {
	duk_idx_t idx_value = -1;
	duk_hobject *getter = NULL;
	duk_hobject *setter = NULL;
	duk_bool_t is_data_desc = 0;
	duk_bool_t is_acc_desc = 0;
	duk_uint_t defprop_flags = 0;

	DUK_ASSERT(out_defprop_flags != NULL);
	DUK_ASSERT(out_idx_value != NULL);
	DUK_ASSERT(out_getter != NULL);
	DUK_ASSERT(out_setter != NULL);
	DUK_ASSERT(idx_in <= 0x7fffL);  /* short variants would be OK, but not used to avoid shifts */

	/* Must be an object, otherwise TypeError (E5.1 Section 8.10.5, step 1). */
	idx_in = duk_require_normalize_index(thr, idx_in);
	(void) duk_require_hobject(thr, idx_in);

	/* The coercion order must match the ToPropertyDescriptor() algorithm
	 * so that side effects in coercion happen in the correct order.
	 * (This order also happens to be compatible with duk_def_prop(),
	 * although it doesn't matter in practice.)
	 */

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_VALUE)) {
		is_data_desc = 1;
		defprop_flags |= DUK_DEFPROP_HAVE_VALUE;
		idx_value = duk_get_top_index(thr);
	}

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_WRITABLE)) {
		is_data_desc = 1;
		if (duk_to_boolean_top_pop(thr)) {
			defprop_flags |= DUK_DEFPROP_HAVE_WRITABLE | DUK_DEFPROP_WRITABLE;
		} else {
			defprop_flags |= DUK_DEFPROP_HAVE_WRITABLE;
		}
	}

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_GET)) {
		duk_tval *tv = duk_require_tval(thr, -1);
		duk_hobject *h_get;

		if (DUK_TVAL_IS_UNDEFINED(tv)) {
			/* undefined is accepted */
			DUK_ASSERT(getter == NULL);
		} else {
			/* NOTE: lightfuncs are coerced to full functions because
			 * lightfuncs don't fit into a property value slot.  This
			 * has some side effects, see test-dev-lightfunc-accessor.js.
			 */
			h_get = duk_get_hobject_promote_lfunc(thr, -1);
			if (h_get == NULL || !DUK_HOBJECT_IS_CALLABLE(h_get)) {
				goto type_error;
			}
			getter = h_get;
		}
		is_acc_desc = 1;
		defprop_flags |= DUK_DEFPROP_HAVE_GETTER;
	}

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_SET)) {
		duk_tval *tv = duk_require_tval(thr, -1);
		duk_hobject *h_set;

		if (DUK_TVAL_IS_UNDEFINED(tv)) {
			/* undefined is accepted */
			DUK_ASSERT(setter == NULL);
		}  else {
			/* NOTE: lightfuncs are coerced to full functions because
			 * lightfuncs don't fit into a property value slot.  This
			 * has some side effects, see test-dev-lightfunc-accessor.js.
			 */
			h_set = duk_get_hobject_promote_lfunc(thr, -1);
			if (h_set == NULL || !DUK_HOBJECT_IS_CALLABLE(h_set)) {
				goto type_error;
			}
			setter = h_set;
		}
		is_acc_desc = 1;
		defprop_flags |= DUK_DEFPROP_HAVE_SETTER;
	}

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_ENUMERABLE)) {
		if (duk_to_boolean_top_pop(thr)) {
			defprop_flags |= DUK_DEFPROP_HAVE_ENUMERABLE | DUK_DEFPROP_ENUMERABLE;
		} else {
			defprop_flags |= DUK_DEFPROP_HAVE_ENUMERABLE;
		}
	}

	if (duk_get_prop_stridx(thr, idx_in, DUK_STRIDX_CONFIGURABLE)) {
		if (duk_to_boolean_top_pop(thr)) {
			defprop_flags |= DUK_DEFPROP_HAVE_CONFIGURABLE | DUK_DEFPROP_CONFIGURABLE;
		} else {
			defprop_flags |= DUK_DEFPROP_HAVE_CONFIGURABLE;
		}
	}

	if (is_data_desc && is_acc_desc) {
		goto type_error;
	}

	*out_defprop_flags = defprop_flags;
	*out_idx_value = idx_value;
	*out_getter = getter;
	*out_setter = setter;

	/* [ ... [multiple values] ] */
	return;

 type_error:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_DESCRIPTOR);
	DUK_WO_NORETURN(return;);
}

/*
 *  Object.defineProperty() related helper (E5 Section 15.2.3.6).
 *  Also handles ES2015 Reflect.defineProperty().
 *
 *  Inlines all [[DefineOwnProperty]] exotic behaviors.
 *
 *  Note: ECMAScript compliant [[DefineOwnProperty]](P, Desc, Throw) is not
 *  implemented directly, but Object.defineProperty() serves its purpose.
 *  We don't need the [[DefineOwnProperty]] internally and we don't have a
 *  property descriptor with 'missing values' so it's easier to avoid it
 *  entirely.
 *
 *  Note: this is only called for actual objects, not primitive values.
 *  This must support virtual properties for full objects (e.g. Strings)
 *  but not for plain values (e.g. strings).  Lightfuncs, even though
 *  primitive in a sense, are treated like objects and accepted as target
 *  values.
 */

/* XXX: this is a major target for size optimization */
DUK_INTERNAL
duk_bool_t duk_hobject_define_property_helper(duk_hthread *thr,
                                              duk_uint_t defprop_flags,
                                              duk_hobject *obj,
                                              duk_hstring *key,
                                              duk_idx_t idx_value,
                                              duk_hobject *get,
                                              duk_hobject *set,
                                              duk_bool_t throw_flag) {
	duk_uint32_t arr_idx;
	duk_tval tv;
	duk_bool_t has_enumerable;
	duk_bool_t has_configurable;
	duk_bool_t has_writable;
	duk_bool_t has_value;
	duk_bool_t has_get;
	duk_bool_t has_set;
	duk_bool_t is_enumerable;
	duk_bool_t is_configurable;
	duk_bool_t is_writable;
	duk_bool_t force_flag;
	duk_small_uint_t new_flags;
	duk_propdesc curr;
	duk_uint32_t arridx_new_array_length;  /* != 0 => post-update for array 'length' (used when key is an array index) */
	duk_uint32_t arrlen_old_len;
	duk_uint32_t arrlen_new_len;
	duk_bool_t pending_write_protect;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT(key != NULL);
	/* idx_value may be < 0 (no value), set and get may be NULL */

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

	/* All the flags fit in 16 bits, so will fit into duk_bool_t. */

	has_writable = (defprop_flags & DUK_DEFPROP_HAVE_WRITABLE);
	has_enumerable = (defprop_flags & DUK_DEFPROP_HAVE_ENUMERABLE);
	has_configurable = (defprop_flags & DUK_DEFPROP_HAVE_CONFIGURABLE);
	has_value = (defprop_flags & DUK_DEFPROP_HAVE_VALUE);
	has_get = (defprop_flags & DUK_DEFPROP_HAVE_GETTER);
	has_set = (defprop_flags & DUK_DEFPROP_HAVE_SETTER);
	is_writable = (defprop_flags & DUK_DEFPROP_WRITABLE);
	is_enumerable = (defprop_flags & DUK_DEFPROP_ENUMERABLE);
	is_configurable = (defprop_flags & DUK_DEFPROP_CONFIGURABLE);
	force_flag = (defprop_flags & DUK_DEFPROP_FORCE);

	arr_idx = DUK_HSTRING_GET_ARRIDX_SLOW(key);

	arridx_new_array_length = 0;
	pending_write_protect = 0;
	arrlen_old_len = 0;
	arrlen_new_len = 0;

	DUK_DDD(DUK_DDDPRINT("has_enumerable=%ld is_enumerable=%ld "
	                     "has_configurable=%ld is_configurable=%ld "
	                     "has_writable=%ld is_writable=%ld "
	                     "has_value=%ld value=%!T "
	                     "has_get=%ld get=%p=%!O "
	                     "has_set=%ld set=%p=%!O "
	                     "arr_idx=%ld throw_flag=!%ld",
	                     (long) has_enumerable, (long) is_enumerable,
	                     (long) has_configurable, (long) is_configurable,
	                     (long) has_writable, (long) is_writable,
	                     (long) has_value, (duk_tval *) (idx_value >= 0 ? duk_get_tval(thr, idx_value) : NULL),
	                     (long) has_get, (void *) get, (duk_heaphdr *) get,
	                     (long) has_set, (void *) set, (duk_heaphdr *) set,
	                     (long) arr_idx, (long) throw_flag));

	/*
	 *  Array exotic behaviors can be implemented at this point.  The local variables
	 *  are essentially a 'value copy' of the input descriptor (Desc), which is modified
	 *  by the Array [[DefineOwnProperty]] (E5 Section 15.4.5.1).
	 */

	if (!DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
		goto skip_array_exotic;
	}

	if (key == DUK_HTHREAD_STRING_LENGTH(thr)) {
		duk_harray *a;

		/* E5 Section 15.4.5.1, step 3, steps a - i are implemented here, j - n at the end */
		if (!has_value) {
			DUK_DDD(DUK_DDDPRINT("exotic array behavior for 'length', but no value in descriptor -> normal behavior"));
			goto skip_array_exotic;
		}

		DUK_DDD(DUK_DDDPRINT("exotic array behavior for 'length', value present in descriptor -> exotic behavior"));

		/*
		 *  Get old and new length
		 */

		a = (duk_harray *) obj;
		DUK_HARRAY_ASSERT_VALID(a);
		arrlen_old_len = a->length;

		DUK_ASSERT(idx_value >= 0);
		arrlen_new_len = duk__to_new_array_length_checked(thr, DUK_GET_TVAL_POSIDX(thr, idx_value));
		duk_push_u32(thr, arrlen_new_len);
		duk_replace(thr, idx_value);  /* step 3.e: replace 'Desc.[[Value]]' */

		DUK_DDD(DUK_DDDPRINT("old_len=%ld, new_len=%ld", (long) arrlen_old_len, (long) arrlen_new_len));

		if (arrlen_new_len >= arrlen_old_len) {
			/* standard behavior, step 3.f.i */
			DUK_DDD(DUK_DDDPRINT("new length is same or higher as previous => standard behavior"));
			goto skip_array_exotic;
		}
		DUK_DDD(DUK_DDDPRINT("new length is smaller than previous => exotic post behavior"));

		/* XXX: consolidated algorithm step 15.f -> redundant? */
		if (DUK_HARRAY_LENGTH_NONWRITABLE(a) && !force_flag) {
			/* Array .length is always non-configurable; if it's also
			 * non-writable, don't allow it to be written.
			 */
			goto fail_not_configurable;
		}

		/* steps 3.h and 3.i */
		if (has_writable && !is_writable) {
			DUK_DDD(DUK_DDDPRINT("desc writable is false, force it back to true, and flag pending write protect"));
			is_writable = 1;
			pending_write_protect = 1;
		}

		/* remaining actual steps are carried out if standard DefineOwnProperty succeeds */
	} else if (arr_idx != DUK__NO_ARRAY_INDEX) {
		/* XXX: any chance of unifying this with the 'length' key handling? */

		/* E5 Section 15.4.5.1, step 4 */
		duk_uint32_t old_len;
		duk_harray *a;

		a = (duk_harray *) obj;
		DUK_HARRAY_ASSERT_VALID(a);

		old_len = a->length;

		if (arr_idx >= old_len) {
			DUK_DDD(DUK_DDDPRINT("defineProperty requires array length update "
			                     "(arr_idx=%ld, old_len=%ld)",
			                     (long) arr_idx, (long) old_len));

			if (DUK_HARRAY_LENGTH_NONWRITABLE(a) && !force_flag) {
				/* Array .length is always non-configurable, so
				 * if it's also non-writable, don't allow a value
				 * write.  With force flag allow writing.
				 */
				goto fail_not_configurable;
			}

			/* actual update happens once write has been completed without
			 * error below.
			 */
			DUK_ASSERT(arr_idx != 0xffffffffUL);
			arridx_new_array_length = arr_idx + 1;
		} else {
			DUK_DDD(DUK_DDDPRINT("defineProperty does not require length update "
			                     "(arr_idx=%ld, old_len=%ld) -> standard behavior",
			                     (long) arr_idx, (long) old_len));
		}
	}
 skip_array_exotic:

	/* XXX: There is currently no support for writing buffer object
	 * indexed elements here.  Attempt to do so will succeed and
	 * write a concrete property into the buffer object.  This should
	 * be fixed at some point but because buffers are a custom feature
	 * anyway, this is relatively unimportant.
	 */

	/*
	 *  Actual Object.defineProperty() default algorithm.
	 */

	/*
	 *  First check whether property exists; if not, simple case.  This covers
	 *  steps 1-4.
	 */

	if (!duk__get_own_propdesc_raw(thr, obj, key, arr_idx, &curr, DUK_GETDESC_FLAG_PUSH_VALUE)) {
		DUK_DDD(DUK_DDDPRINT("property does not exist"));

		if (!DUK_HOBJECT_HAS_EXTENSIBLE(obj) && !force_flag) {
			goto fail_not_extensible;
		}

#if defined(DUK_USE_ROM_OBJECTS)
		/* ROM objects are never extensible but force flag may
		 * allow us to come here anyway.
		 */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj) || !DUK_HOBJECT_HAS_EXTENSIBLE(obj));
		if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
			DUK_D(DUK_DPRINT("attempt to define property on a read-only target object"));
			goto fail_not_configurable;
		}
#endif

		/* XXX: share final setting code for value and flags?  difficult because
		 * refcount code is different.  Share entry allocation?  But can't allocate
		 * until array index checked.
		 */

		/* steps 4.a and 4.b are tricky */
		if (has_set || has_get) {
			duk_int_t e_idx;

			DUK_DDD(DUK_DDDPRINT("create new accessor property"));

			DUK_ASSERT(has_set || set == NULL);
			DUK_ASSERT(has_get || get == NULL);
			DUK_ASSERT(!has_value);
			DUK_ASSERT(!has_writable);

			new_flags = DUK_PROPDESC_FLAG_ACCESSOR;  /* defaults, E5 Section 8.6.1, Table 7 */
			if (has_enumerable && is_enumerable) {
				new_flags |= DUK_PROPDESC_FLAG_ENUMERABLE;
			}
			if (has_configurable && is_configurable) {
				new_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
			}

			if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
				DUK_DDD(DUK_DDDPRINT("accessor cannot go to array part, abandon array"));
				duk__abandon_array_part(thr, obj);
			}

			/* write to entry part */
			e_idx = duk__hobject_alloc_entry_checked(thr, obj, key);
			DUK_ASSERT(e_idx >= 0);

			DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, obj, e_idx, get);
			DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, obj, e_idx, set);
			DUK_HOBJECT_INCREF_ALLOWNULL(thr, get);
			DUK_HOBJECT_INCREF_ALLOWNULL(thr, set);

			DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, e_idx, new_flags);
			goto success_exotics;
		} else {
			duk_int_t e_idx;
			duk_tval *tv2;

			DUK_DDD(DUK_DDDPRINT("create new data property"));

			DUK_ASSERT(!has_set);
			DUK_ASSERT(!has_get);

			new_flags = 0;  /* defaults, E5 Section 8.6.1, Table 7 */
			if (has_writable && is_writable) {
				new_flags |= DUK_PROPDESC_FLAG_WRITABLE;
			}
			if (has_enumerable && is_enumerable) {
				new_flags |= DUK_PROPDESC_FLAG_ENUMERABLE;
			}
			if (has_configurable && is_configurable) {
				new_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
			}
			if (has_value) {
				duk_tval *tv_tmp = duk_require_tval(thr, idx_value);
				DUK_TVAL_SET_TVAL(&tv, tv_tmp);
			} else {
				DUK_TVAL_SET_UNDEFINED(&tv);  /* default value */
			}

			if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HOBJECT_HAS_ARRAY_PART(obj)) {
				if (new_flags == DUK_PROPDESC_FLAGS_WEC) {
					DUK_DDD(DUK_DDDPRINT("new data property attributes match array defaults, attempt to write to array part"));
					tv2 = duk__obtain_arridx_slot(thr, arr_idx, obj);
					if (tv2 == NULL) {
						DUK_DDD(DUK_DDDPRINT("failed writing to array part, abandoned array"));
					} else {
						DUK_DDD(DUK_DDDPRINT("success in writing to array part"));
						DUK_ASSERT(DUK_HOBJECT_HAS_ARRAY_PART(obj));
						DUK_ASSERT(DUK_TVAL_IS_UNUSED(tv2));
						DUK_TVAL_SET_TVAL(tv2, &tv);
						DUK_TVAL_INCREF(thr, tv2);
						goto success_exotics;
					}
				} else {
					DUK_DDD(DUK_DDDPRINT("new data property cannot go to array part, abandon array"));
					duk__abandon_array_part(thr, obj);
				}
				/* fall through */
			}

			/* write to entry part */
			e_idx = duk__hobject_alloc_entry_checked(thr, obj, key);
			DUK_ASSERT(e_idx >= 0);
			tv2 = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, e_idx);
			DUK_TVAL_SET_TVAL(tv2, &tv);
			DUK_TVAL_INCREF(thr, tv2);

			DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, e_idx, new_flags);
			goto success_exotics;
		}
		DUK_UNREACHABLE();
	}

	/* we currently assume virtual properties are not configurable (as none of them are) */
	DUK_ASSERT((curr.e_idx >= 0 || curr.a_idx >= 0) || !(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE));

	/* [obj key desc value get set curr_value] */

	/*
	 *  Property already exists.  Steps 5-6 detect whether any changes need
	 *  to be made.
	 */

	if (has_enumerable) {
		if (is_enumerable) {
			if (!(curr.flags & DUK_PROPDESC_FLAG_ENUMERABLE)) {
				goto need_check;
			}
		} else {
			if (curr.flags & DUK_PROPDESC_FLAG_ENUMERABLE) {
				goto need_check;
			}
		}
	}
	if (has_configurable) {
		if (is_configurable) {
			if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE)) {
				goto need_check;
			}
		} else {
			if (curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) {
				goto need_check;
			}
		}
	}
	if (has_value) {
		duk_tval *tmp1;
		duk_tval *tmp2;

		/* attempt to change from accessor to data property */
		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			goto need_check;
		}

		tmp1 = duk_require_tval(thr, -1);         /* curr value */
		tmp2 = duk_require_tval(thr, idx_value);  /* new value */
		if (!duk_js_samevalue(tmp1, tmp2)) {
			goto need_check;
		}
	}
	if (has_writable) {
		/* attempt to change from accessor to data property */
		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			goto need_check;
		}

		if (is_writable) {
			if (!(curr.flags & DUK_PROPDESC_FLAG_WRITABLE)) {
				goto need_check;
			}
		} else {
			if (curr.flags & DUK_PROPDESC_FLAG_WRITABLE) {
				goto need_check;
			}
		}
	}
	if (has_set) {
		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			if (set != curr.set) {
				goto need_check;
			}
		} else {
			goto need_check;
		}
	}
	if (has_get) {
		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			if (get != curr.get) {
				goto need_check;
			}
		} else {
			goto need_check;
		}
	}

	/* property exists, either 'desc' is empty, or all values
	 * match (SameValue)
	 */
	goto success_no_exotics;

 need_check:

	/*
	 *  Some change(s) need to be made.  Steps 7-11.
	 */

	/* shared checks for all descriptor types */
	if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) && !force_flag) {
		if (has_configurable && is_configurable) {
			goto fail_not_configurable;
		}
		if (has_enumerable) {
			if (curr.flags & DUK_PROPDESC_FLAG_ENUMERABLE) {
				if (!is_enumerable) {
					goto fail_not_configurable;
				}
			} else {
				if (is_enumerable) {
					goto fail_not_configurable;
				}
			}
		}
	}

	/* Virtual properties don't have backing so they can't mostly be
	 * edited.  Some virtual properties are, however, writable: for
	 * example, virtual index properties of buffer objects and Array
	 * instance .length.  These are not configurable so the checks
	 * above mostly cover attempts to change them, except when the
	 * duk_def_prop() call is used with DUK_DEFPROP_FORCE; even in
	 * that case we can't forcibly change the property attributes
	 * because they don't have concrete backing.
	 */

	/* XXX: for ROM objects too it'd be best if value modify was
	 * allowed if the value matches SameValue.
	 */
	/* Reject attempt to change a read-only object. */
#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_DD(DUK_DDPRINT("attempt to define property on read-only target object"));
		goto fail_not_configurable;
	}
#endif

	/* descriptor type specific checks */
	if (has_set || has_get) {
		/* IsAccessorDescriptor(desc) == true */
		DUK_ASSERT(!has_writable);
		DUK_ASSERT(!has_value);

		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			/* curr and desc are accessors */
			if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) && !force_flag) {
				if (has_set && set != curr.set) {
					goto fail_not_configurable;
				}
				if (has_get && get != curr.get) {
					goto fail_not_configurable;
				}
			}
		} else {
			duk_bool_t rc;
			duk_tval *tv1;

			/* curr is data, desc is accessor */
			if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) && !force_flag) {
				goto fail_not_configurable;
			}

			DUK_DDD(DUK_DDDPRINT("convert property to accessor property"));
			if (curr.a_idx >= 0) {
				DUK_DDD(DUK_DDDPRINT("property to convert is stored in an array entry, abandon array and re-lookup"));
				duk__abandon_array_part(thr, obj);
				duk_pop_unsafe(thr);  /* remove old value */
				rc = duk__get_own_propdesc_raw(thr, obj, key, arr_idx, &curr, DUK_GETDESC_FLAG_PUSH_VALUE);
				DUK_UNREF(rc);
				DUK_ASSERT(rc != 0);
				DUK_ASSERT(curr.e_idx >= 0 && curr.a_idx < 0);
			}
			if (curr.e_idx < 0) {
				DUK_ASSERT(curr.a_idx < 0 && curr.e_idx < 0);
				goto fail_virtual;  /* safeguard for virtual property */
			}

			DUK_ASSERT(curr.e_idx >= 0);
			DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, curr.e_idx));

			tv1 = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, curr.e_idx);
			DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, tv1);  /* XXX: just decref */

			DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, obj, curr.e_idx, NULL);
			DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, obj, curr.e_idx, NULL);
			DUK_HOBJECT_E_SLOT_CLEAR_WRITABLE(thr->heap, obj, curr.e_idx);
			DUK_HOBJECT_E_SLOT_SET_ACCESSOR(thr->heap, obj, curr.e_idx);

			DUK_DDD(DUK_DDDPRINT("flags after data->accessor conversion: 0x%02lx",
			                     (unsigned long) DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, curr.e_idx)));
			/* Update curr.flags; faster than a re-lookup. */
			curr.flags &= ~DUK_PROPDESC_FLAG_WRITABLE;
			curr.flags |= DUK_PROPDESC_FLAG_ACCESSOR;
		}
	} else if (has_value || has_writable) {
		/* IsDataDescriptor(desc) == true */
		DUK_ASSERT(!has_set);
		DUK_ASSERT(!has_get);

		if (curr.flags & DUK_PROPDESC_FLAG_ACCESSOR) {
			duk_hobject *tmp;

			/* curr is accessor, desc is data */
			if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) && !force_flag) {
				goto fail_not_configurable;
			}

			/* curr is accessor -> cannot be in array part. */
			DUK_ASSERT(curr.a_idx < 0);
			if (curr.e_idx < 0) {
				goto fail_virtual;  /* safeguard; no virtual accessors now */
			}

			DUK_DDD(DUK_DDDPRINT("convert property to data property"));

			DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, curr.e_idx));
			tmp = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, obj, curr.e_idx);
			DUK_UNREF(tmp);
			DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, obj, curr.e_idx, NULL);
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, tmp);
			tmp = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, obj, curr.e_idx);
			DUK_UNREF(tmp);
			DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, obj, curr.e_idx, NULL);
			DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, tmp);

			DUK_TVAL_SET_UNDEFINED(DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, curr.e_idx));
			DUK_HOBJECT_E_SLOT_CLEAR_WRITABLE(thr->heap, obj, curr.e_idx);
			DUK_HOBJECT_E_SLOT_CLEAR_ACCESSOR(thr->heap, obj, curr.e_idx);

			DUK_DDD(DUK_DDDPRINT("flags after accessor->data conversion: 0x%02lx",
			                     (unsigned long) DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, curr.e_idx)));

			/* Update curr.flags; faster than a re-lookup. */
			curr.flags &= ~(DUK_PROPDESC_FLAG_WRITABLE | DUK_PROPDESC_FLAG_ACCESSOR);
		} else {
			/* curr and desc are data */
			if (!(curr.flags & DUK_PROPDESC_FLAG_CONFIGURABLE) && !force_flag) {
				if (!(curr.flags & DUK_PROPDESC_FLAG_WRITABLE) && has_writable && is_writable) {
					goto fail_not_configurable;
				}
				/* Note: changing from writable to non-writable is OK */
				if (!(curr.flags & DUK_PROPDESC_FLAG_WRITABLE) && has_value) {
					duk_tval *tmp1 = duk_require_tval(thr, -1);         /* curr value */
					duk_tval *tmp2 = duk_require_tval(thr, idx_value);  /* new value */
					if (!duk_js_samevalue(tmp1, tmp2)) {
						goto fail_not_configurable;
					}
				}
			}
		}
	} else {
		/* IsGenericDescriptor(desc) == true; this means in practice that 'desc'
		 * only has [[Enumerable]] or [[Configurable]] flag updates, which are
		 * allowed at this point.
		 */

		DUK_ASSERT(!has_value && !has_writable && !has_get && !has_set);
	}

	/*
	 *  Start doing property attributes updates.  Steps 12-13.
	 *
	 *  Start by computing new attribute flags without writing yet.
	 *  Property type conversion is done above if necessary.
	 */

	new_flags = curr.flags;

	if (has_enumerable) {
		if (is_enumerable) {
			new_flags |= DUK_PROPDESC_FLAG_ENUMERABLE;
		} else {
			new_flags &= ~DUK_PROPDESC_FLAG_ENUMERABLE;
		}
	}
	if (has_configurable) {
		if (is_configurable) {
			new_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
		} else {
			new_flags &= ~DUK_PROPDESC_FLAG_CONFIGURABLE;
		}
	}
	if (has_writable) {
		if (is_writable) {
			new_flags |= DUK_PROPDESC_FLAG_WRITABLE;
		} else {
			new_flags &= ~DUK_PROPDESC_FLAG_WRITABLE;
		}
	}

	/* XXX: write protect after flag? -> any chance of handling it here? */

	DUK_DDD(DUK_DDDPRINT("new flags that we want to write: 0x%02lx",
	                     (unsigned long) new_flags));

	/*
	 *  Check whether we need to abandon an array part (if it exists)
	 */

	if (curr.a_idx >= 0) {
		duk_bool_t rc;

		DUK_ASSERT(curr.e_idx < 0);

		if (new_flags == DUK_PROPDESC_FLAGS_WEC) {
			duk_tval *tv1, *tv2;

			DUK_DDD(DUK_DDDPRINT("array index, new property attributes match array defaults, update in-place"));

			DUK_ASSERT(curr.flags == DUK_PROPDESC_FLAGS_WEC);  /* must have been, since in array part */
			DUK_ASSERT(!has_set);
			DUK_ASSERT(!has_get);
			DUK_ASSERT(idx_value >= 0);  /* must be: if attributes match and we get here the value must differ (otherwise no change) */

			tv2 = duk_require_tval(thr, idx_value);
			tv1 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, curr.a_idx);
			DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects; may invalidate a_idx */
			goto success_exotics;
		}

		DUK_DDD(DUK_DDDPRINT("array index, new property attributes do not match array defaults, abandon array and re-lookup"));
		duk__abandon_array_part(thr, obj);
		duk_pop_unsafe(thr);  /* remove old value */
		rc = duk__get_own_propdesc_raw(thr, obj, key, arr_idx, &curr, DUK_GETDESC_FLAG_PUSH_VALUE);
		DUK_UNREF(rc);
		DUK_ASSERT(rc != 0);
		DUK_ASSERT(curr.e_idx >= 0 && curr.a_idx < 0);
	}

	DUK_DDD(DUK_DDDPRINT("updating existing property in entry part"));

	/* Array case is handled comprehensively above: either in entry
	 * part or a virtual property.
	 */
	DUK_ASSERT(curr.a_idx < 0);

	DUK_DDD(DUK_DDDPRINT("update existing property attributes"));
	if (curr.e_idx >= 0) {
		DUK_HOBJECT_E_SET_FLAGS(thr->heap, obj, curr.e_idx, new_flags);
	} else {
		/* For Array .length the only allowed transition is for .length
		 * to become non-writable.
		 */
		if (key == DUK_HTHREAD_STRING_LENGTH(thr) && DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
			duk_harray *a;
			a = (duk_harray *) obj;
			DUK_DD(DUK_DDPRINT("Object.defineProperty() attribute update for duk_harray .length -> %02lx", (unsigned long) new_flags));
			DUK_HARRAY_ASSERT_VALID(a);
			if ((new_flags & DUK_PROPDESC_FLAGS_EC) != (curr.flags & DUK_PROPDESC_FLAGS_EC)) {
				DUK_D(DUK_DPRINT("Object.defineProperty() attempt to change virtual array .length enumerable or configurable attribute, fail"));
				goto fail_virtual;
			}
			if (new_flags & DUK_PROPDESC_FLAG_WRITABLE) {
				DUK_HARRAY_SET_LENGTH_WRITABLE(a);
			} else {
				DUK_HARRAY_SET_LENGTH_NONWRITABLE(a);
			}
		}
	}

	if (has_set) {
		duk_hobject *tmp;

		/* Virtual properties are non-configurable but with a 'force'
		 * flag we might come here so check explicitly for virtual.
		 */
		if (curr.e_idx < 0) {
			goto fail_virtual;
		}

		DUK_DDD(DUK_DDDPRINT("update existing property setter"));
		DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, curr.e_idx));

		tmp = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, obj, curr.e_idx);
		DUK_UNREF(tmp);
		DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, obj, curr.e_idx, set);
		DUK_HOBJECT_INCREF_ALLOWNULL(thr, set);
		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);  /* side effects; may invalidate e_idx */
	}
	if (has_get) {
		duk_hobject *tmp;

		if (curr.e_idx < 0) {
			goto fail_virtual;
		}

		DUK_DDD(DUK_DDDPRINT("update existing property getter"));
		DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, curr.e_idx));

		tmp = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, obj, curr.e_idx);
		DUK_UNREF(tmp);
		DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, obj, curr.e_idx, get);
		DUK_HOBJECT_INCREF_ALLOWNULL(thr, get);
		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);  /* side effects; may invalidate e_idx */
	}
	if (has_value) {
		duk_tval *tv1, *tv2;

		DUK_DDD(DUK_DDDPRINT("update existing property value"));

		if (curr.e_idx >= 0) {
			DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, obj, curr.e_idx));
			tv2 = duk_require_tval(thr, idx_value);
			tv1 = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, obj, curr.e_idx);
			DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects; may invalidate e_idx */
		} else {
			DUK_ASSERT(curr.a_idx < 0);  /* array part case handled comprehensively previously */

			DUK_DD(DUK_DDPRINT("Object.defineProperty(), value update for virtual property"));
			/* XXX: Uint8Array and other typed array virtual writes not currently
			 * handled.
			 */
			if (key == DUK_HTHREAD_STRING_LENGTH(thr) && DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
				duk_harray *a;
				a = (duk_harray *) obj;
				DUK_DD(DUK_DDPRINT("Object.defineProperty() value update for duk_harray .length -> %ld", (long) arrlen_new_len));
				DUK_HARRAY_ASSERT_VALID(a);
				a->length = arrlen_new_len;
			} else {
				goto fail_virtual;  /* should not happen */
			}
		}
	}

	/*
	 *  Standard algorithm succeeded without errors, check for exotic post-behaviors.
	 *
	 *  Arguments exotic behavior in E5 Section 10.6 occurs after the standard
	 *  [[DefineOwnProperty]] has completed successfully.
	 *
	 *  Array exotic behavior in E5 Section 15.4.5.1 is implemented partly
	 *  prior to the default [[DefineOwnProperty]], but:
	 *    - for an array index key (e.g. "10") the final 'length' update occurs here
	 *    - for 'length' key the element deletion and 'length' update occurs here
	 */

 success_exotics:

	/* curr.a_idx or curr.e_idx may have been invalidated by side effects
	 * above.
	 */

	/* [obj key desc value get set curr_value] */

	if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj)) {
		duk_harray *a;

		a = (duk_harray *) obj;
		DUK_HARRAY_ASSERT_VALID(a);

		if (arridx_new_array_length > 0) {
			/*
			 *  Note: zero works as a "no update" marker because the new length
			 *  can never be zero after a new property is written.
			 */

			/* E5 Section 15.4.5.1, steps 4.e.i - 4.e.ii */

			DUK_DDD(DUK_DDDPRINT("defineProperty successful, pending array length update to: %ld",
			                     (long) arridx_new_array_length));

			a->length = arridx_new_array_length;
		}

		if (key == DUK_HTHREAD_STRING_LENGTH(thr) && arrlen_new_len < arrlen_old_len) {
			/*
			 *  E5 Section 15.4.5.1, steps 3.k - 3.n.  The order at the end combines
			 *  the error case 3.l.iii and the success case 3.m-3.n.
			 */

			/* XXX: investigate whether write protect can be handled above, if we
			 * just update length here while ignoring its protected status
			 */

			duk_uint32_t result_len;
			duk_bool_t rc;

			DUK_DDD(DUK_DDDPRINT("defineProperty successful, key is 'length', exotic array behavior, "
			                     "doing array element deletion and length update"));

			rc = duk__handle_put_array_length_smaller(thr, obj, arrlen_old_len, arrlen_new_len, force_flag, &result_len);

			/* update length (curr points to length, and we assume it's still valid) */
			DUK_ASSERT(result_len >= arrlen_new_len && result_len <= arrlen_old_len);

			a->length = result_len;

			if (pending_write_protect) {
				DUK_DDD(DUK_DDDPRINT("setting array length non-writable (pending writability update)"));
				DUK_HARRAY_SET_LENGTH_NONWRITABLE(a);
			}

			/* XXX: shrink array allocation or entries compaction here? */
			if (!rc) {
				DUK_DD(DUK_DDPRINT("array length write only partially successful"));
				goto fail_not_configurable;
			}
		}
	} else if (arr_idx != DUK__NO_ARRAY_INDEX && DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj)) {
		duk_hobject *map;
		duk_hobject *varenv;

		DUK_ASSERT(arridx_new_array_length == 0);
		DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(obj));  /* traits are separate; in particular, arguments not an array */

		map = NULL;
		varenv = NULL;
		if (!duk__lookup_arguments_map(thr, obj, key, &curr, &map, &varenv)) {
			goto success_no_exotics;
		}
		DUK_ASSERT(map != NULL);
		DUK_ASSERT(varenv != NULL);

		/* [obj key desc value get set curr_value varname] */

		if (has_set || has_get) {
			/* = IsAccessorDescriptor(Desc) */
			DUK_DDD(DUK_DDDPRINT("defineProperty successful, key mapped to arguments 'map' "
			                     "changed to an accessor, delete arguments binding"));

			(void) duk_hobject_delprop_raw(thr, map, key, 0);  /* ignore result */
		} else {
			/* Note: this order matters (final value before deleting map entry must be done) */
			DUK_DDD(DUK_DDDPRINT("defineProperty successful, key mapped to arguments 'map', "
			                     "check for value update / binding deletion"));

			if (has_value) {
				duk_hstring *varname;

				DUK_DDD(DUK_DDDPRINT("defineProperty successful, key mapped to arguments 'map', "
				                     "update bound value (variable/argument)"));

				varname = duk_require_hstring(thr, -1);
				DUK_ASSERT(varname != NULL);

				DUK_DDD(DUK_DDDPRINT("arguments object automatic putvar for a bound variable; "
				                     "key=%!O, varname=%!O, value=%!T",
				                     (duk_heaphdr *) key,
				                     (duk_heaphdr *) varname,
				                     (duk_tval *) duk_require_tval(thr, idx_value)));

				/* strict flag for putvar comes from our caller (currently: fixed) */
				duk_js_putvar_envrec(thr, varenv, varname, duk_require_tval(thr, idx_value), 1 /*throw_flag*/);
			}
			if (has_writable && !is_writable) {
				DUK_DDD(DUK_DDDPRINT("defineProperty successful, key mapped to arguments 'map', "
				                     "changed to non-writable, delete arguments binding"));

				(void) duk_hobject_delprop_raw(thr, map, key, 0);  /* ignore result */
			}
		}

		/* 'varname' is in stack in this else branch, leaving an unbalanced stack below,
		 * but this doesn't matter now.
		 */
	}

 success_no_exotics:
	/* Some code paths use NORZ macros for simplicity, ensure refzero
	 * handling is completed.
	 */
	DUK_REFZERO_CHECK_SLOW(thr);
	return 1;

 fail_not_extensible:
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_EXTENSIBLE);
		DUK_WO_NORETURN(return 0;);
	}
	return 0;

 fail_virtual:  /* just use the same "not configurable" error message" */
 fail_not_configurable:
	if (throw_flag) {
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);
		DUK_WO_NORETURN(return 0;);
	}
	return 0;
}

/*
 *  Object.prototype.hasOwnProperty() and Object.prototype.propertyIsEnumerable().
 */

DUK_INTERNAL duk_bool_t duk_hobject_object_ownprop_helper(duk_hthread *thr, duk_small_uint_t required_desc_flags) {
	duk_hstring *h_v;
	duk_hobject *h_obj;
	duk_propdesc desc;
	duk_bool_t ret;

	/* coercion order matters */
	h_v = duk_to_hstring_acceptsymbol(thr, 0);
	DUK_ASSERT(h_v != NULL);

	h_obj = duk_push_this_coercible_to_object(thr);
	DUK_ASSERT(h_obj != NULL);

	ret = duk_hobject_get_own_propdesc(thr, h_obj, h_v, &desc, 0 /*flags*/);  /* don't push value */

	duk_push_boolean(thr, ret && ((desc.flags & required_desc_flags) == required_desc_flags));
	return 1;
}

/*
 *  Object.seal() and Object.freeze()  (E5 Sections 15.2.3.8 and 15.2.3.9)
 *
 *  Since the algorithms are similar, a helper provides both functions.
 *  Freezing is essentially sealing + making plain properties non-writable.
 *
 *  Note: virtual (non-concrete) properties which are non-configurable but
 *  writable would pose some problems, but such properties do not currently
 *  exist (all virtual properties are non-configurable and non-writable).
 *  If they did exist, the non-configurability does NOT prevent them from
 *  becoming non-writable.  However, this change should be recorded somehow
 *  so that it would turn up (e.g. when getting the property descriptor),
 *  requiring some additional flags in the object.
 */

DUK_INTERNAL void duk_hobject_object_seal_freeze_helper(duk_hthread *thr, duk_hobject *obj, duk_bool_t is_freeze) {
	duk_uint_fast32_t i;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(obj != NULL);

	DUK_ASSERT_VALSTACK_SPACE(thr, DUK__VALSTACK_SPACE);

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj)) {
		DUK_DD(DUK_DDPRINT("attempt to seal/freeze a readonly object, reject"));
		DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONFIGURABLE);
		DUK_WO_NORETURN(return;);
	}
#endif

	/*
	 *  Abandon array part because all properties must become non-configurable.
	 *  Note that this is now done regardless of whether this is always the case
	 *  (skips check, but performance problem if caller would do this many times
	 *  for the same object; not likely).
	 */

	duk__abandon_array_part(thr, obj);
	DUK_ASSERT(DUK_HOBJECT_GET_ASIZE(obj) == 0);

	for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
		duk_uint8_t *fp;

		/* since duk__abandon_array_part() causes a resize, there should be no gaps in keys */
		DUK_ASSERT(DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i) != NULL);

		/* avoid multiple computations of flags address; bypasses macros */
		fp = DUK_HOBJECT_E_GET_FLAGS_PTR(thr->heap, obj, i);
		if (is_freeze && !((*fp) & DUK_PROPDESC_FLAG_ACCESSOR)) {
			*fp &= ~(DUK_PROPDESC_FLAG_WRITABLE | DUK_PROPDESC_FLAG_CONFIGURABLE);
		} else {
			*fp &= ~DUK_PROPDESC_FLAG_CONFIGURABLE;
		}
	}

	DUK_HOBJECT_CLEAR_EXTENSIBLE(obj);

	/* no need to compact since we already did that in duk__abandon_array_part()
	 * (regardless of whether an array part existed or not.
	 */

	return;
}

/*
 *  Object.isSealed() and Object.isFrozen()  (E5 Sections 15.2.3.11, 15.2.3.13)
 *
 *  Since the algorithms are similar, a helper provides both functions.
 *  Freezing is essentially sealing + making plain properties non-writable.
 *
 *  Note: all virtual (non-concrete) properties are currently non-configurable
 *  and non-writable (and there are no accessor virtual properties), so they don't
 *  need to be considered here now.
 */

DUK_INTERNAL duk_bool_t duk_hobject_object_is_sealed_frozen_helper(duk_hthread *thr, duk_hobject *obj, duk_bool_t is_frozen) {
	duk_uint_fast32_t i;

	DUK_ASSERT(obj != NULL);
	DUK_UNREF(thr);

	/* Note: no allocation pressure, no need to check refcounts etc */

	/* must not be extensible */
	if (DUK_HOBJECT_HAS_EXTENSIBLE(obj)) {
		return 0;
	}

	/* all virtual properties are non-configurable and non-writable */

	/* entry part must not contain any configurable properties, or
	 * writable properties (if is_frozen).
	 */
	for (i = 0; i < DUK_HOBJECT_GET_ENEXT(obj); i++) {
		duk_small_uint_t flags;

		if (!DUK_HOBJECT_E_GET_KEY(thr->heap, obj, i)) {
			continue;
		}

		/* avoid multiple computations of flags address; bypasses macros */
		flags = (duk_small_uint_t) DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, i);

		if (flags & DUK_PROPDESC_FLAG_CONFIGURABLE) {
			return 0;
		}
		if (is_frozen &&
		    !(flags & DUK_PROPDESC_FLAG_ACCESSOR) &&
		    (flags & DUK_PROPDESC_FLAG_WRITABLE)) {
			return 0;
		}
	}

	/* array part must not contain any non-unused properties, as they would
	 * be configurable and writable.
	 */
	for (i = 0; i < DUK_HOBJECT_GET_ASIZE(obj); i++) {
		duk_tval *tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, i);
		if (!DUK_TVAL_IS_UNUSED(tv)) {
			return 0;
		}
	}

	return 1;
}

/*
 *  Object.preventExtensions() and Object.isExtensible()  (E5 Sections 15.2.3.10, 15.2.3.13)
 *
 *  Not needed, implemented by macros DUK_HOBJECT_{HAS,CLEAR,SET}_EXTENSIBLE
 *  and the Object built-in bindings.
 */

/* automatic undefs */
#undef DUK__HASH_DELETED
#undef DUK__HASH_UNUSED
#undef DUK__NO_ARRAY_INDEX
#undef DUK__VALSTACK_PROXY_LOOKUP
#undef DUK__VALSTACK_SPACE
/*
 *  duk_hstring assertion helpers.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ASSERTIONS)

DUK_INTERNAL void duk_hstring_assert_valid(duk_hstring *h) {
	DUK_ASSERT(h != NULL);
}

#endif  /* DUK_USE_ASSERTIONS */
/*
 *  Misc support functions
 */

/* #include duk_internal.h -> already included */

/*
 *  duk_hstring charCodeAt, with and without surrogate awareness
 */

DUK_INTERNAL duk_ucodepoint_t duk_hstring_char_code_at_raw(duk_hthread *thr, duk_hstring *h, duk_uint_t pos, duk_bool_t surrogate_aware) {
	duk_uint32_t boff;
	const duk_uint8_t *p, *p_start, *p_end;
	duk_ucodepoint_t cp1;
	duk_ucodepoint_t cp2;

	/* Caller must check character offset to be inside the string. */
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	DUK_ASSERT_DISABLE(pos >= 0);  /* unsigned */
	DUK_ASSERT(pos < (duk_uint_t) DUK_HSTRING_GET_CHARLEN(h));

	boff = (duk_uint32_t) duk_heap_strcache_offset_char2byte(thr, h, (duk_uint32_t) pos);
	DUK_DDD(DUK_DDDPRINT("charCodeAt: pos=%ld -> boff=%ld, str=%!O",
	                     (long) pos, (long) boff, (duk_heaphdr *) h));
	DUK_ASSERT_DISABLE(boff >= 0);
	DUK_ASSERT(boff < DUK_HSTRING_GET_BYTELEN(h));

	p_start = DUK_HSTRING_GET_DATA(h);
	p_end = p_start + DUK_HSTRING_GET_BYTELEN(h);
	p = p_start + boff;
	DUK_DDD(DUK_DDDPRINT("p_start=%p, p_end=%p, p=%p",
	                     (const void *) p_start, (const void *) p_end,
	                     (const void *) p));

	/* For invalid UTF-8 (never happens for standard ECMAScript strings)
	 * return U+FFFD replacement character.
	 */
	if (duk_unicode_decode_xutf8(thr, &p, p_start, p_end, &cp1)) {
		if (surrogate_aware && cp1 >= 0xd800UL && cp1 <= 0xdbffUL) {
			/* The decode helper is memory safe even if 'cp1' was
			 * decoded at the end of the string and 'p' is no longer
			 * within string memory range.
			 */
			cp2 = 0;  /* If call fails, this is left untouched and won't match cp2 check. */
			(void) duk_unicode_decode_xutf8(thr, &p, p_start, p_end, &cp2);
			if (cp2 >= 0xdc00UL && cp2 <= 0xdfffUL) {
				cp1 = (duk_ucodepoint_t) (((cp1 - 0xd800UL) << 10) + (cp2 - 0xdc00UL) + 0x10000UL);
			}
		}
	} else {
		cp1 = DUK_UNICODE_CP_REPLACEMENT_CHARACTER;
	}

	return cp1;
}

/*
 *  duk_hstring charlen, when lazy charlen disabled
 */

#if !defined(DUK_USE_HSTRING_LAZY_CLEN)
#if !defined(DUK_USE_HSTRING_CLEN)
#error non-lazy duk_hstring charlen but DUK_USE_HSTRING_CLEN not set
#endif
DUK_INTERNAL void duk_hstring_init_charlen(duk_hstring *h) {
	duk_uint32_t clen;

	DUK_ASSERT(h != NULL);
	DUK_ASSERT(!DUK_HSTRING_HAS_ASCII(h));
	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h));

	clen = duk_unicode_unvalidated_utf8_length(DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
#if defined(DUK_USE_STRLEN16)
	DUK_ASSERT(clen <= 0xffffUL);  /* Bytelength checked during interning. */
	h->clen16 = (duk_uint16_t) clen;
#else
	h->clen = (duk_uint32_t) clen;
#endif
	if (DUK_LIKELY(clen == DUK_HSTRING_GET_BYTELEN(h))) {
		DUK_HSTRING_SET_ASCII(h);
	}
}

DUK_INTERNAL DUK_HOT duk_size_t duk_hstring_get_charlen(duk_hstring *h) {
#if defined(DUK_USE_STRLEN16)
	return h->clen16;
#else
	return h->clen;
#endif
}
#endif  /* !DUK_USE_HSTRING_LAZY_CLEN */

/*
 *  duk_hstring charlen, when lazy charlen enabled
 */

#if defined(DUK_USE_HSTRING_LAZY_CLEN)
#if defined(DUK_USE_HSTRING_CLEN)
DUK_LOCAL DUK_COLD duk_size_t duk__hstring_get_charlen_slowpath(duk_hstring *h) {
	duk_size_t res;

	DUK_ASSERT(h->clen == 0);  /* Checked by caller. */

#if defined(DUK_USE_ROM_STRINGS)
	/* ROM strings have precomputed clen, but if the computed clen is zero
	 * we can still come here and can't write anything.
	 */
	if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h)) {
		return 0;
	}
#endif

	res = duk_unicode_unvalidated_utf8_length(DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
#if defined(DUK_USE_STRLEN16)
	DUK_ASSERT(res <= 0xffffUL);  /* Bytelength checked during interning. */
	h->clen16 = (duk_uint16_t) res;
#else
	h->clen = (duk_uint32_t) res;
#endif
	if (DUK_LIKELY(res == DUK_HSTRING_GET_BYTELEN(h))) {
		DUK_HSTRING_SET_ASCII(h);
	}
	return res;
}
#else  /* DUK_USE_HSTRING_CLEN */
DUK_LOCAL duk_size_t duk__hstring_get_charlen_slowpath(duk_hstring *h) {
	if (DUK_LIKELY(DUK_HSTRING_HAS_ASCII(h))) {
		/* Most practical strings will go here. */
		return DUK_HSTRING_GET_BYTELEN(h);
	} else {
		/* ASCII flag is lazy, so set it here. */
		duk_size_t res;

		/* XXX: here we could use the strcache to speed up the
		 * computation (matters for 'i < str.length' loops).
		 */

		res = duk_unicode_unvalidated_utf8_length(DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));

#if defined(DUK_USE_ROM_STRINGS)
		if (DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) h)) {
			/* For ROM strings, can't write anything; ASCII flag
			 * is preset so we don't need to update it.
			 */
			return res;
		}
#endif
		if (DUK_LIKELY(res == DUK_HSTRING_GET_BYTELEN(h))) {
			DUK_HSTRING_SET_ASCII(h);
		}
		return res;
	}
}
#endif  /* DUK_USE_HSTRING_CLEN */

#if defined(DUK_USE_HSTRING_CLEN)
DUK_INTERNAL DUK_HOT duk_size_t duk_hstring_get_charlen(duk_hstring *h) {
#if defined(DUK_USE_STRLEN16)
	if (DUK_LIKELY(h->clen16 != 0)) {
		return h->clen16;
	}
#else
	if (DUK_LIKELY(h->clen != 0)) {
		return h->clen;
	}
#endif
	return duk__hstring_get_charlen_slowpath(h);
}
#else  /* DUK_USE_HSTRING_CLEN */
DUK_INTERNAL DUK_HOT duk_size_t duk_hstring_get_charlen(duk_hstring *h) {
	/* Always use slow path. */
	return duk__hstring_get_charlen_slowpath(h);
}
#endif  /* DUK_USE_HSTRING_CLEN */
#endif  /* DUK_USE_HSTRING_LAZY_CLEN */

/*
 *  Compare duk_hstring to an ASCII cstring.
 */

DUK_INTERNAL duk_bool_t duk_hstring_equals_ascii_cstring(duk_hstring *h, const char *cstr) {
	duk_size_t len;

	DUK_ASSERT(h != NULL);
	DUK_ASSERT(cstr != NULL);

	len = DUK_STRLEN(cstr);
	if (len != DUK_HSTRING_GET_BYTELEN(h)) {
		return 0;
	}
	if (duk_memcmp((const void *) cstr, (const void *) DUK_HSTRING_GET_DATA(h), len) == 0) {
		return 1;
	}
	return 0;
}
/*
 *  duk_hthread allocation and freeing.
 */

/* #include duk_internal.h -> already included */

/*
 *  Allocate initial stacks for a thread.  Note that 'thr' must be reachable
 *  as a garbage collection may be triggered by the allocation attempts.
 *  Returns zero (without leaking memory) if init fails.
 */

DUK_INTERNAL duk_bool_t duk_hthread_init_stacks(duk_heap *heap, duk_hthread *thr) {
	duk_size_t alloc_size;
	duk_size_t i;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->valstack == NULL);
	DUK_ASSERT(thr->valstack_end == NULL);
	DUK_ASSERT(thr->valstack_alloc_end == NULL);
	DUK_ASSERT(thr->valstack_bottom == NULL);
	DUK_ASSERT(thr->valstack_top == NULL);
	DUK_ASSERT(thr->callstack_curr == NULL);

	/* valstack */
	DUK_ASSERT(DUK_VALSTACK_API_ENTRY_MINIMUM <= DUK_VALSTACK_INITIAL_SIZE);
	alloc_size = sizeof(duk_tval) * DUK_VALSTACK_INITIAL_SIZE;
	thr->valstack = (duk_tval *) DUK_ALLOC(heap, alloc_size);
	if (!thr->valstack) {
		goto fail;
	}
	duk_memzero(thr->valstack, alloc_size);
	thr->valstack_end = thr->valstack + DUK_VALSTACK_API_ENTRY_MINIMUM;
	thr->valstack_alloc_end = thr->valstack + DUK_VALSTACK_INITIAL_SIZE;
	thr->valstack_bottom = thr->valstack;
	thr->valstack_top = thr->valstack;

	for (i = 0; i < DUK_VALSTACK_INITIAL_SIZE; i++) {
		DUK_TVAL_SET_UNDEFINED(&thr->valstack[i]);
	}

	return 1;

 fail:
	DUK_FREE(heap, thr->valstack);
	DUK_ASSERT(thr->callstack_curr == NULL);

	thr->valstack = NULL;
	return 0;
}

/* For indirect allocs. */

DUK_INTERNAL void *duk_hthread_get_valstack_ptr(duk_heap *heap, void *ud) {
	duk_hthread *thr = (duk_hthread *) ud;
	DUK_UNREF(heap);
	return (void *) thr->valstack;
}
/*
 *  Initialize built-in objects.  Current thread must have a valstack
 *  and initialization errors may longjmp, so a setjmp() catch point
 *  must exist.
 */

/* #include duk_internal.h -> already included */

/*
 *  Encoding constants, must match genbuiltins.py
 */

#define DUK__PROP_FLAGS_BITS             3
#define DUK__LENGTH_PROP_BITS            3
#define DUK__NARGS_BITS                  3
#define DUK__PROP_TYPE_BITS              3

#define DUK__NARGS_VARARGS_MARKER        0x07

#define DUK__PROP_TYPE_DOUBLE            0
#define DUK__PROP_TYPE_STRING            1
#define DUK__PROP_TYPE_STRIDX            2
#define DUK__PROP_TYPE_BUILTIN           3
#define DUK__PROP_TYPE_UNDEFINED         4
#define DUK__PROP_TYPE_BOOLEAN_TRUE      5
#define DUK__PROP_TYPE_BOOLEAN_FALSE     6
#define DUK__PROP_TYPE_ACCESSOR          7

/*
 *  Create built-in objects by parsing an init bitstream generated
 *  by genbuiltins.py.
 */

#if defined(DUK_USE_ROM_OBJECTS)
#if defined(DUK_USE_ROM_GLOBAL_CLONE) || defined(DUK_USE_ROM_GLOBAL_INHERIT)
DUK_LOCAL void duk__duplicate_ram_global_object(duk_hthread *thr) {
	duk_hobject *h_global;
#if defined(DUK_USE_ROM_GLOBAL_CLONE)
	duk_hobject *h_oldglobal;
	duk_uint8_t *props;
	duk_size_t alloc_size;
#endif
	duk_hobject *h_objenv;

	/* XXX: refactor into internal helper, duk_clone_hobject() */

#if defined(DUK_USE_ROM_GLOBAL_INHERIT)
	/* Inherit from ROM-based global object: less RAM usage, less transparent. */
	h_global = duk_push_object_helper(thr,
	                                  DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                  DUK_HOBJECT_FLAG_FASTREFS |
	                                  DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_GLOBAL),
	                                  DUK_BIDX_GLOBAL);
	DUK_ASSERT(h_global != NULL);
#elif defined(DUK_USE_ROM_GLOBAL_CLONE)
	/* Clone the properties of the ROM-based global object to create a
	 * fully RAM-based global object.  Uses more memory than the inherit
	 * model but more compliant.
	 */
	h_global = duk_push_object_helper(thr,
	                                  DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                  DUK_HOBJECT_FLAG_FASTREFS |
	                                  DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_GLOBAL),
	                                  DUK_BIDX_OBJECT_PROTOTYPE);
	DUK_ASSERT(h_global != NULL);
	h_oldglobal = thr->builtins[DUK_BIDX_GLOBAL];
	DUK_ASSERT(h_oldglobal != NULL);

	/* Copy the property table verbatim; this handles attributes etc.
	 * For ROM objects it's not necessary (or possible) to update
	 * refcounts so leave them as is.
	 */
	alloc_size = DUK_HOBJECT_P_ALLOC_SIZE(h_oldglobal);
	DUK_ASSERT(alloc_size > 0);
	props = DUK_ALLOC_CHECKED(thr, alloc_size);
	DUK_ASSERT(props != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, h_oldglobal) != NULL);
	duk_memcpy((void *) props, (const void *) DUK_HOBJECT_GET_PROPS(thr->heap, h_oldglobal), alloc_size);

	/* XXX: keep property attributes or tweak them here?
	 * Properties will now be non-configurable even when they're
	 * normally configurable for the global object.
	 */

	DUK_ASSERT(DUK_HOBJECT_GET_PROPS(thr->heap, h_global) == NULL);
	DUK_HOBJECT_SET_PROPS(thr->heap, h_global, props);
	DUK_HOBJECT_SET_ESIZE(h_global, DUK_HOBJECT_GET_ESIZE(h_oldglobal));
	DUK_HOBJECT_SET_ENEXT(h_global, DUK_HOBJECT_GET_ENEXT(h_oldglobal));
	DUK_HOBJECT_SET_ASIZE(h_global, DUK_HOBJECT_GET_ASIZE(h_oldglobal));
	DUK_HOBJECT_SET_HSIZE(h_global, DUK_HOBJECT_GET_HSIZE(h_oldglobal));
#else
#error internal error in config defines
#endif

	duk_hobject_compact_props(thr, h_global);
	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL] != NULL);
	DUK_ASSERT(!DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE((duk_heaphdr *) thr->builtins[DUK_BIDX_GLOBAL]));  /* no need to decref: ROM object */
	thr->builtins[DUK_BIDX_GLOBAL] = h_global;
	DUK_HOBJECT_INCREF(thr, h_global);
	DUK_D(DUK_DPRINT("duplicated global object: %!O", h_global));

	/* Create a fresh object environment for the global scope.  This is
	 * needed so that the global scope points to the newly created RAM-based
	 * global object.
	 */
	h_objenv = (duk_hobject *) duk_hobjenv_alloc(thr,
	                                             DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                             DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJENV));
	DUK_ASSERT(h_objenv != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_objenv) == NULL);
	duk_push_hobject(thr, h_objenv);

	DUK_ASSERT(h_global != NULL);
	((duk_hobjenv *) h_objenv)->target = h_global;
	DUK_HOBJECT_INCREF(thr, h_global);
	DUK_ASSERT(((duk_hobjenv *) h_objenv)->has_this == 0);

	DUK_ASSERT(thr->builtins[DUK_BIDX_GLOBAL_ENV] != NULL);
	DUK_ASSERT(!DUK_HEAPHDR_NEEDS_REFCOUNT_UPDATE((duk_heaphdr *) thr->builtins[DUK_BIDX_GLOBAL_ENV]));  /* no need to decref: ROM object */
	thr->builtins[DUK_BIDX_GLOBAL_ENV] = h_objenv;
	DUK_HOBJECT_INCREF(thr, h_objenv);
	DUK_D(DUK_DPRINT("duplicated global env: %!O", h_objenv));

	DUK_HOBJENV_ASSERT_VALID((duk_hobjenv *) h_objenv);

	duk_pop_2(thr);  /* Pop global object and global env. */
}
#endif  /* DUK_USE_ROM_GLOBAL_CLONE || DUK_USE_ROM_GLOBAL_INHERIT */

DUK_INTERNAL void duk_hthread_create_builtin_objects(duk_hthread *thr) {
	/* Setup builtins from ROM objects.  All heaps/threads will share
	 * the same readonly objects.
	 */
	duk_small_uint_t i;

	for (i = 0; i < DUK_NUM_BUILTINS; i++) {
		duk_hobject *h;
		h = (duk_hobject *) DUK_LOSE_CONST(duk_rom_builtins_bidx[i]);
		DUK_ASSERT(h != NULL);
		thr->builtins[i] = h;
	}

#if defined(DUK_USE_ROM_GLOBAL_CLONE) || defined(DUK_USE_ROM_GLOBAL_INHERIT)
	/* By default the global object is read-only which is often much
	 * more of an issue than having read-only built-in objects (like
	 * RegExp, Date, etc).  Use a RAM-based copy of the global object
	 * and the global environment object for convenience.
	 */
	duk__duplicate_ram_global_object(thr);
#endif
}
#else  /* DUK_USE_ROM_OBJECTS */
DUK_LOCAL void duk__push_stridx(duk_hthread *thr, duk_bitdecoder_ctx *bd) {
	duk_small_uint_t n;

	n = (duk_small_uint_t) duk_bd_decode_varuint(bd);
	DUK_ASSERT_DISABLE(n >= 0);  /* unsigned */
	DUK_ASSERT(n < DUK_HEAP_NUM_STRINGS);
	duk_push_hstring_stridx(thr, n);
}
DUK_LOCAL void duk__push_string(duk_hthread *thr, duk_bitdecoder_ctx *bd) {
	/* XXX: built-ins data could provide a maximum length that is
	 * actually needed; bitpacked max length is now 256 bytes.
	 */
	duk_uint8_t tmp[DUK_BD_BITPACKED_STRING_MAXLEN];
	duk_small_uint_t len;

	len = duk_bd_decode_bitpacked_string(bd, tmp);
	duk_push_lstring(thr, (const char *) tmp, (duk_size_t) len);
}
DUK_LOCAL void duk__push_stridx_or_string(duk_hthread *thr, duk_bitdecoder_ctx *bd) {
	duk_small_uint_t n;

	n = (duk_small_uint_t) duk_bd_decode_varuint(bd);
	if (n == 0) {
		duk__push_string(thr, bd);
	} else {
		n--;
		DUK_ASSERT(n < DUK_HEAP_NUM_STRINGS);
		duk_push_hstring_stridx(thr, n);
	}
}
DUK_LOCAL void duk__push_double(duk_hthread *thr, duk_bitdecoder_ctx *bd) {
	duk_double_union du;
	duk_small_uint_t i;

	for (i = 0; i < 8; i++) {
		/* Encoding endianness must match target memory layout,
		 * build scripts and genbuiltins.py must ensure this.
		 */
		du.uc[i] = (duk_uint8_t) duk_bd_decode(bd, 8);
	}

	duk_push_number(thr, du.d);  /* push operation normalizes NaNs */
}

DUK_INTERNAL void duk_hthread_create_builtin_objects(duk_hthread *thr) {
	duk_bitdecoder_ctx bd_ctx;
	duk_bitdecoder_ctx *bd = &bd_ctx;  /* convenience */
	duk_hobject *h;
	duk_small_uint_t i, j;

	DUK_D(DUK_DPRINT("INITBUILTINS BEGIN: DUK_NUM_BUILTINS=%d, DUK_NUM_BUILTINS_ALL=%d", (int) DUK_NUM_BUILTINS, (int) DUK_NUM_ALL_BUILTINS));

	duk_memzero(&bd_ctx, sizeof(bd_ctx));
	bd->data = (const duk_uint8_t *) duk_builtins_data;
	bd->length = (duk_size_t) DUK_BUILTINS_DATA_LENGTH;

	/*
	 *  First create all built-in bare objects on the empty valstack.
	 *
	 *  Built-ins in the index range [0,DUK_NUM_BUILTINS-1] have value
	 *  stack indices matching their eventual thr->builtins[] index.
	 *
	 *  Built-ins in the index range [DUK_NUM_BUILTINS,DUK_NUM_ALL_BUILTINS]
	 *  will exist on the value stack during init but won't be placed
	 *  into thr->builtins[].  These are objects referenced in some way
	 *  from thr->builtins[] roots but which don't need to be indexed by
	 *  Duktape through thr->builtins[] (e.g. user custom objects).
	 *
	 *  Internal prototypes will be incorrect (NULL) at this stage.
	 */

	duk_require_stack(thr, DUK_NUM_ALL_BUILTINS);

	DUK_DD(DUK_DDPRINT("create empty built-ins"));
	DUK_ASSERT_TOP(thr, 0);
	for (i = 0; i < DUK_NUM_ALL_BUILTINS; i++) {
		duk_small_uint_t class_num;
		duk_small_int_t len = -1;  /* must be signed */

		class_num = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		len = (duk_small_int_t) duk_bd_decode_flagged_signed(bd, DUK__LENGTH_PROP_BITS, (duk_int32_t) -1 /*def_value*/);

		if (class_num == DUK_HOBJECT_CLASS_FUNCTION) {
			duk_small_uint_t natidx;
			duk_small_int_t c_nargs;  /* must hold DUK_VARARGS */
			duk_c_function c_func;
			duk_int16_t magic;

			DUK_DDD(DUK_DDDPRINT("len=%ld", (long) len));
			DUK_ASSERT(len >= 0);

			natidx = (duk_small_uint_t) duk_bd_decode_varuint(bd);
			DUK_ASSERT(natidx != 0);
			c_func = duk_bi_native_functions[natidx];
			DUK_ASSERT(c_func != NULL);

			c_nargs = (duk_small_int_t) duk_bd_decode_flagged_signed(bd, DUK__NARGS_BITS, len /*def_value*/);
			if (c_nargs == DUK__NARGS_VARARGS_MARKER) {
				c_nargs = DUK_VARARGS;
			}

			/* XXX: set magic directly here? (it could share the c_nargs arg) */
			(void) duk_push_c_function_builtin(thr, c_func, c_nargs);
			h = duk_known_hobject(thr, -1);

			/* Currently all built-in native functions are strict.
			 * duk_push_c_function() now sets strict flag, so
			 * assert for it.
			 */
			DUK_ASSERT(DUK_HOBJECT_HAS_STRICT(h));

			/* XXX: function properties */

			duk__push_stridx_or_string(thr, bd);
#if defined(DUK_USE_FUNC_NAME_PROPERTY)
			duk_xdef_prop_stridx_short(thr,
			                           -2,
			                           DUK_STRIDX_NAME,
			                           DUK_PROPDESC_FLAGS_C);
#else
			duk_pop(thr);  /* Not very ideal but good enough for now. */
#endif

			/* Almost all global level Function objects are constructable
			 * but not all: Function.prototype is a non-constructable,
			 * callable Function.
			 */
			if (duk_bd_decode_flag(bd)) {
				DUK_ASSERT(DUK_HOBJECT_HAS_CONSTRUCTABLE(h));
			} else {
				DUK_HOBJECT_CLEAR_CONSTRUCTABLE(h);
			}

			/* Cast converts magic to 16-bit signed value */
			magic = (duk_int16_t) duk_bd_decode_varuint(bd);
			((duk_hnatfunc *) h)->magic = magic;
		} else if (class_num == DUK_HOBJECT_CLASS_ARRAY) {
			duk_push_array(thr);
		} else if (class_num == DUK_HOBJECT_CLASS_OBJENV) {
			duk_hobjenv *env;
			duk_hobject *global;

			DUK_ASSERT(i == DUK_BIDX_GLOBAL_ENV);
			DUK_ASSERT(DUK_BIDX_GLOBAL_ENV > DUK_BIDX_GLOBAL);

			env = duk_hobjenv_alloc(thr,
	                                        DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJENV));
			DUK_ASSERT(env->target == NULL);
			duk_push_hobject(thr, (duk_hobject *) env);

			global = duk_known_hobject(thr, DUK_BIDX_GLOBAL);
			DUK_ASSERT(global != NULL);
			env->target = global;
			DUK_HOBJECT_INCREF(thr, global);
			DUK_ASSERT(env->has_this == 0);

			DUK_HOBJENV_ASSERT_VALID(env);
		} else {
			DUK_ASSERT(class_num != DUK_HOBJECT_CLASS_DECENV);

			(void) duk_push_object_helper(thr,
			                              DUK_HOBJECT_FLAG_FASTREFS |
			                              DUK_HOBJECT_FLAG_EXTENSIBLE,
			                              -1);  /* no prototype or class yet */

		}

		h = duk_known_hobject(thr, -1);
		DUK_HOBJECT_SET_CLASS_NUMBER(h, class_num);

		if (i < DUK_NUM_BUILTINS) {
			thr->builtins[i] = h;
			DUK_HOBJECT_INCREF(thr, &h->hdr);
		}

		if (len >= 0) {
			/* In ES2015+ built-in function object .length property
			 * has property attributes C (configurable only):
			 * http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-standard-built-in-objects
			 *
			 * Array.prototype remains an Array instance in ES2015+
			 * and its length has attributes W (writable only).
			 * Because .length is now virtual for duk_harray, it is
			 * not encoded explicitly in init data.
			 */

			DUK_ASSERT(class_num != DUK_HOBJECT_CLASS_ARRAY);  /* .length is virtual */
			duk_push_int(thr, len);
			duk_xdef_prop_stridx_short(thr,
			                           -2,
			                           DUK_STRIDX_LENGTH,
			                           DUK_PROPDESC_FLAGS_C);
		}

		/* enable exotic behaviors last */

		if (class_num == DUK_HOBJECT_CLASS_ARRAY) {
			DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY(h));  /* set by duk_push_array() */
		}
		if (class_num == DUK_HOBJECT_CLASS_STRING) {
			DUK_HOBJECT_SET_EXOTIC_STRINGOBJ(h);
		}

		/* some assertions */

		DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(h));
		/* DUK_HOBJECT_FLAG_CONSTRUCTABLE varies */
		DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(h));
		DUK_ASSERT(!DUK_HOBJECT_HAS_COMPFUNC(h));
		/* DUK_HOBJECT_FLAG_NATFUNC varies */
		DUK_ASSERT(!DUK_HOBJECT_IS_THREAD(h));
		DUK_ASSERT(!DUK_HOBJECT_IS_PROXY(h));
		DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(h) || class_num == DUK_HOBJECT_CLASS_ARRAY);
		/* DUK_HOBJECT_FLAG_STRICT varies */
		DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(h) ||  /* all native functions have NEWENV */
		           DUK_HOBJECT_HAS_NEWENV(h));
		DUK_ASSERT(!DUK_HOBJECT_HAS_NAMEBINDING(h));
		DUK_ASSERT(!DUK_HOBJECT_HAS_CREATEARGS(h));
		/* DUK_HOBJECT_FLAG_EXOTIC_ARRAY varies */
		/* DUK_HOBJECT_FLAG_EXOTIC_STRINGOBJ varies */
		DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(h));

		DUK_DDD(DUK_DDDPRINT("created built-in %ld, class=%ld, length=%ld", (long) i, (long) class_num, (long) len));
	}

	/*
	 *  Then decode the builtins init data (see genbuiltins.py) to
	 *  init objects.  Internal prototypes are set at this stage,
	 *  with thr->builtins[] populated.
	 */

	DUK_DD(DUK_DDPRINT("initialize built-in object properties"));
	for (i = 0; i < DUK_NUM_ALL_BUILTINS; i++) {
		duk_small_uint_t t;
		duk_small_uint_t num;

		DUK_DDD(DUK_DDDPRINT("initializing built-in object at index %ld", (long) i));
		h = duk_known_hobject(thr, (duk_idx_t) i);

		t = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		if (t > 0) {
			t--;
			DUK_DDD(DUK_DDDPRINT("set internal prototype: built-in %ld", (long) t));
			DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, h, duk_known_hobject(thr, (duk_idx_t) t));
		} else if (DUK_HOBJECT_IS_NATFUNC(h)) {
			/* Standard native built-ins cannot inherit from
			 * %NativeFunctionPrototype%, they are required to
			 * inherit from Function.prototype directly.
			 */
			DUK_ASSERT(thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE] != NULL);
			DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, h, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
		}

		t = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		if (t > 0) {
			/* 'prototype' property for all built-in objects (which have it) has attributes:
			 *  [[Writable]] = false,
			 *  [[Enumerable]] = false,
			 *  [[Configurable]] = false
			 */
			t--;
			DUK_DDD(DUK_DDDPRINT("set external prototype: built-in %ld", (long) t));
			duk_dup(thr, (duk_idx_t) t);
			duk_xdef_prop_stridx(thr, (duk_idx_t) i, DUK_STRIDX_PROTOTYPE, DUK_PROPDESC_FLAGS_NONE);
		}

		t = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		if (t > 0) {
			/* 'constructor' property for all built-in objects (which have it) has attributes:
			 *  [[Writable]] = true,
			 *  [[Enumerable]] = false,
			 *  [[Configurable]] = true
			 */
			t--;
			DUK_DDD(DUK_DDDPRINT("set external constructor: built-in %ld", (long) t));
			duk_dup(thr, (duk_idx_t) t);
			duk_xdef_prop_stridx(thr, (duk_idx_t) i, DUK_STRIDX_CONSTRUCTOR, DUK_PROPDESC_FLAGS_WC);
		}

		/* normal valued properties */
		num = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		DUK_DDD(DUK_DDDPRINT("built-in object %ld, %ld normal valued properties", (long) i, (long) num));
		for (j = 0; j < num; j++) {
			duk_small_uint_t defprop_flags;

			duk__push_stridx_or_string(thr, bd);

			/*
			 *  Property attribute defaults are defined in E5 Section 15 (first
			 *  few pages); there is a default for all properties and a special
			 *  default for 'length' properties.  Variation from the defaults is
			 *  signaled using a single flag bit in the bitstream.
			 */

			defprop_flags = (duk_small_uint_t) duk_bd_decode_flagged(bd,
			                                                         DUK__PROP_FLAGS_BITS,
			                                                         (duk_uint32_t) DUK_PROPDESC_FLAGS_WC);
			defprop_flags |= DUK_DEFPROP_FORCE |
			                 DUK_DEFPROP_HAVE_VALUE |
			                 DUK_DEFPROP_HAVE_WRITABLE |
			                 DUK_DEFPROP_HAVE_ENUMERABLE |
			                 DUK_DEFPROP_HAVE_CONFIGURABLE;  /* Defaults for data properties. */

			/* The writable, enumerable, configurable flags in prop_flags
			 * match both duk_def_prop() and internal property flags.
			 */
			DUK_ASSERT(DUK_PROPDESC_FLAG_WRITABLE == DUK_DEFPROP_WRITABLE);
			DUK_ASSERT(DUK_PROPDESC_FLAG_ENUMERABLE == DUK_DEFPROP_ENUMERABLE);
			DUK_ASSERT(DUK_PROPDESC_FLAG_CONFIGURABLE == DUK_DEFPROP_CONFIGURABLE);

			t = (duk_small_uint_t) duk_bd_decode(bd, DUK__PROP_TYPE_BITS);

			DUK_DDD(DUK_DDDPRINT("built-in %ld, normal-valued property %ld, key %!T, flags 0x%02lx, type %ld",
			                     (long) i, (long) j, duk_get_tval(thr, -1), (unsigned long) defprop_flags, (long) t));

			switch (t) {
			case DUK__PROP_TYPE_DOUBLE: {
				duk__push_double(thr, bd);
				break;
			}
			case DUK__PROP_TYPE_STRING: {
				duk__push_string(thr, bd);
				break;
			}
			case DUK__PROP_TYPE_STRIDX: {
				duk__push_stridx(thr, bd);
				break;
			}
			case DUK__PROP_TYPE_BUILTIN: {
				duk_small_uint_t bidx;

				bidx = (duk_small_uint_t) duk_bd_decode_varuint(bd);
				duk_dup(thr, (duk_idx_t) bidx);
				break;
			}
			case DUK__PROP_TYPE_UNDEFINED: {
				duk_push_undefined(thr);
				break;
			}
			case DUK__PROP_TYPE_BOOLEAN_TRUE: {
				duk_push_true(thr);
				break;
			}
			case DUK__PROP_TYPE_BOOLEAN_FALSE: {
				duk_push_false(thr);
				break;
			}
			case DUK__PROP_TYPE_ACCESSOR: {
				duk_small_uint_t natidx_getter = (duk_small_uint_t) duk_bd_decode_varuint(bd);
				duk_small_uint_t natidx_setter = (duk_small_uint_t) duk_bd_decode_varuint(bd);
				duk_small_uint_t accessor_magic = (duk_small_uint_t) duk_bd_decode_varuint(bd);
				duk_c_function c_func_getter;
				duk_c_function c_func_setter;

				DUK_DDD(DUK_DDDPRINT("built-in accessor property: objidx=%ld, key=%!T, getteridx=%ld, setteridx=%ld, flags=0x%04lx",
				                     (long) i, duk_get_tval(thr, -1), (long) natidx_getter, (long) natidx_setter, (unsigned long) defprop_flags));

				c_func_getter = duk_bi_native_functions[natidx_getter];
				if (c_func_getter != NULL) {
					duk_push_c_function_builtin_noconstruct(thr, c_func_getter, 0);  /* always 0 args */
					duk_set_magic(thr, -1, (duk_int_t) accessor_magic);
					defprop_flags |= DUK_DEFPROP_HAVE_GETTER;
				}
				c_func_setter = duk_bi_native_functions[natidx_setter];
				if (c_func_setter != NULL) {
					duk_push_c_function_builtin_noconstruct(thr, c_func_setter, 1);  /* always 1 arg */
					duk_set_magic(thr, -1, (duk_int_t) accessor_magic);
					defprop_flags |= DUK_DEFPROP_HAVE_SETTER;
				}

				/* Writable flag doesn't make sense for an accessor. */
				DUK_ASSERT((defprop_flags & DUK_PROPDESC_FLAG_WRITABLE) == 0);  /* genbuiltins.py ensures */

				defprop_flags &= ~(DUK_DEFPROP_HAVE_VALUE | DUK_DEFPROP_HAVE_WRITABLE);
				defprop_flags |= DUK_DEFPROP_HAVE_ENUMERABLE | DUK_DEFPROP_HAVE_CONFIGURABLE;
				break;
			}
			default: {
				/* exhaustive */
				DUK_UNREACHABLE();
			}
			}

			duk_def_prop(thr, (duk_idx_t) i, defprop_flags);
			DUK_ASSERT_TOP(thr, DUK_NUM_ALL_BUILTINS);
		}

		/* native function properties */
		num = (duk_small_uint_t) duk_bd_decode_varuint(bd);
		DUK_DDD(DUK_DDDPRINT("built-in object %ld, %ld function valued properties", (long) i, (long) num));
		for (j = 0; j < num; j++) {
			duk_hstring *h_key;
			duk_small_uint_t natidx;
			duk_int_t c_nargs;  /* must hold DUK_VARARGS */
			duk_small_uint_t c_length;
			duk_int16_t magic;
			duk_c_function c_func;
			duk_hnatfunc *h_func;
#if defined(DUK_USE_LIGHTFUNC_BUILTINS)
			duk_small_int_t lightfunc_eligible;
#endif
			duk_small_uint_t defprop_flags;

			duk__push_stridx_or_string(thr, bd);
			h_key = duk_known_hstring(thr, -1);
			DUK_UNREF(h_key);
			natidx = (duk_small_uint_t) duk_bd_decode_varuint(bd);

			c_length = (duk_small_uint_t) duk_bd_decode(bd, DUK__LENGTH_PROP_BITS);
			c_nargs = (duk_int_t) duk_bd_decode_flagged(bd, DUK__NARGS_BITS, (duk_uint32_t) c_length /*def_value*/);
			if (c_nargs == DUK__NARGS_VARARGS_MARKER) {
				c_nargs = DUK_VARARGS;
			}

			c_func = duk_bi_native_functions[natidx];

			DUK_DDD(DUK_DDDPRINT("built-in %ld, function-valued property %ld, key %!O, natidx %ld, length %ld, nargs %ld",
			                     (long) i, (long) j, (duk_heaphdr *) h_key, (long) natidx, (long) c_length,
			                     (c_nargs == DUK_VARARGS ? (long) -1 : (long) c_nargs)));

			/* Cast converts magic to 16-bit signed value */
			magic = (duk_int16_t) duk_bd_decode_varuint(bd);

#if defined(DUK_USE_LIGHTFUNC_BUILTINS)
			lightfunc_eligible =
				((c_nargs >= DUK_LFUNC_NARGS_MIN && c_nargs <= DUK_LFUNC_NARGS_MAX) || (c_nargs == DUK_VARARGS)) &&
				(c_length <= DUK_LFUNC_LENGTH_MAX) &&
				(magic >= DUK_LFUNC_MAGIC_MIN && magic <= DUK_LFUNC_MAGIC_MAX);

			/* These functions have trouble working as lightfuncs.
			 * Some of them have specific asserts and some may have
		         * additional properties (e.g. 'require.id' may be written).
			 */
			if (c_func == duk_bi_global_object_eval) {
				lightfunc_eligible = 0;
			}
#if defined(DUK_USE_COROUTINE_SUPPORT)
			if (c_func == duk_bi_thread_yield ||
			    c_func == duk_bi_thread_resume) {
				lightfunc_eligible = 0;
			}
#endif
			if (c_func == duk_bi_function_prototype_call ||
			    c_func == duk_bi_function_prototype_apply ||
			    c_func == duk_bi_reflect_apply ||
			    c_func == duk_bi_reflect_construct) {
				lightfunc_eligible = 0;
			}

			if (lightfunc_eligible) {
				duk_tval tv_lfunc;
				duk_small_uint_t lf_nargs = (duk_small_uint_t) (c_nargs == DUK_VARARGS ? DUK_LFUNC_NARGS_VARARGS : c_nargs);
				duk_small_uint_t lf_flags = DUK_LFUNC_FLAGS_PACK(magic, c_length, lf_nargs);
				DUK_TVAL_SET_LIGHTFUNC(&tv_lfunc, c_func, lf_flags);
				duk_push_tval(thr, &tv_lfunc);
				DUK_D(DUK_DPRINT("built-in function eligible as light function: i=%d, j=%d c_length=%ld, c_nargs=%ld, magic=%ld -> %!iT", (int) i, (int) j, (long) c_length, (long) c_nargs, (long) magic, duk_get_tval(thr, -1)));
				goto lightfunc_skip;
			}

			DUK_D(DUK_DPRINT("built-in function NOT ELIGIBLE as light function: i=%d, j=%d c_length=%ld, c_nargs=%ld, magic=%ld", (int) i, (int) j, (long) c_length, (long) c_nargs, (long) magic));
#endif  /* DUK_USE_LIGHTFUNC_BUILTINS */

			/* [ (builtin objects) name ] */

			duk_push_c_function_builtin_noconstruct(thr, c_func, c_nargs);
			h_func = duk_known_hnatfunc(thr, -1);
			DUK_UNREF(h_func);

			/* XXX: add into init data? */

			/* Special call handling, not described in init data. */
			if (c_func == duk_bi_global_object_eval ||
			    c_func == duk_bi_function_prototype_call ||
			    c_func == duk_bi_function_prototype_apply ||
			    c_func == duk_bi_reflect_apply ||
			    c_func == duk_bi_reflect_construct) {
				DUK_HOBJECT_SET_SPECIAL_CALL((duk_hobject *) h_func);
			}

			/* Currently all built-in native functions are strict.
			 * This doesn't matter for many functions, but e.g.
			 * String.prototype.charAt (and other string functions)
			 * rely on being strict so that their 'this' binding is
			 * not automatically coerced.
			 */
			DUK_HOBJECT_SET_STRICT((duk_hobject *) h_func);

			/* No built-in functions are constructable except the top
			 * level ones (Number, etc).
			 */
			DUK_ASSERT(!DUK_HOBJECT_HAS_CONSTRUCTABLE((duk_hobject *) h_func));

			/* XXX: any way to avoid decoding magic bit; there are quite
			 * many function properties and relatively few with magic values.
			 */
			h_func->magic = magic;

			/* [ (builtin objects) name func ] */

			duk_push_uint(thr, c_length);
			duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_C);

			duk_dup_m2(thr);
			duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);

			/* XXX: other properties of function instances; 'arguments', 'caller'. */

			DUK_DD(DUK_DDPRINT("built-in object %ld, function property %ld -> %!T",
			                   (long) i, (long) j, (duk_tval *) duk_get_tval(thr, -1)));

			/* [ (builtin objects) name func ] */

			/*
			 *  The default property attributes are correct for all
			 *  function valued properties of built-in objects now.
			 */

#if defined(DUK_USE_LIGHTFUNC_BUILTINS)
		 lightfunc_skip:
#endif

			defprop_flags = (duk_small_uint_t) duk_bd_decode_flagged(bd,
			                                                         DUK__PROP_FLAGS_BITS,
			                                                         (duk_uint32_t) DUK_PROPDESC_FLAGS_WC);
			defprop_flags |= DUK_DEFPROP_FORCE |
			                 DUK_DEFPROP_HAVE_VALUE |
			                 DUK_DEFPROP_HAVE_WRITABLE |
			                 DUK_DEFPROP_HAVE_ENUMERABLE |
			                 DUK_DEFPROP_HAVE_CONFIGURABLE;
			DUK_ASSERT(DUK_PROPDESC_FLAG_WRITABLE == DUK_DEFPROP_WRITABLE);
			DUK_ASSERT(DUK_PROPDESC_FLAG_ENUMERABLE == DUK_DEFPROP_ENUMERABLE);
			DUK_ASSERT(DUK_PROPDESC_FLAG_CONFIGURABLE == DUK_DEFPROP_CONFIGURABLE);

			duk_def_prop(thr, (duk_idx_t) i, defprop_flags);

			/* [ (builtin objects) ] */
		}
	}

	/*
	 *  Special post-tweaks, for cases not covered by the init data format.
	 *
	 *  - Set Date.prototype.toGMTString to Date.prototype.toUTCString.
	 *    toGMTString is required to have the same Function object as
	 *    toUTCString in E5 Section B.2.6.  Note that while Smjs respects
	 *    this, V8 does not (the Function objects are distinct).
	 *
	 *  - Make DoubleError non-extensible.
	 *
	 *  - Add info about most important effective compile options to Duktape.
	 *
	 *  - Possibly remove some properties (values or methods) which are not
	 *    desirable with current feature options but are not currently
	 *    conditional in init data.
	 */

#if defined(DUK_USE_DATE_BUILTIN)
	duk_get_prop_stridx_short(thr, DUK_BIDX_DATE_PROTOTYPE, DUK_STRIDX_TO_UTC_STRING);
	duk_xdef_prop_stridx_short(thr, DUK_BIDX_DATE_PROTOTYPE, DUK_STRIDX_TO_GMT_STRING, DUK_PROPDESC_FLAGS_WC);
#endif

	h = duk_known_hobject(thr, DUK_BIDX_DOUBLE_ERROR);
	DUK_HOBJECT_CLEAR_EXTENSIBLE(h);

#if !defined(DUK_USE_ES6_OBJECT_PROTO_PROPERTY)
	DUK_DD(DUK_DDPRINT("delete Object.prototype.__proto__ built-in which is not enabled in features"));
	(void) duk_hobject_delprop_raw(thr, thr->builtins[DUK_BIDX_OBJECT_PROTOTYPE], DUK_HTHREAD_STRING___PROTO__(thr), DUK_DELPROP_FLAG_THROW);
#endif

#if !defined(DUK_USE_ES6_OBJECT_SETPROTOTYPEOF)
	DUK_DD(DUK_DDPRINT("delete Object.setPrototypeOf built-in which is not enabled in features"));
	(void) duk_hobject_delprop_raw(thr, thr->builtins[DUK_BIDX_OBJECT_CONSTRUCTOR], DUK_HTHREAD_STRING_SET_PROTOTYPE_OF(thr), DUK_DELPROP_FLAG_THROW);
#endif

	/* XXX: relocate */
	duk_push_string(thr,
			/* Endianness indicator */
#if defined(DUK_USE_INTEGER_LE)
	                "l"
#elif defined(DUK_USE_INTEGER_BE)
	                "b"
#elif defined(DUK_USE_INTEGER_ME)  /* integer mixed endian not really used now */
	                "m"
#else
	                "?"
#endif
#if defined(DUK_USE_DOUBLE_LE)
	                "l"
#elif defined(DUK_USE_DOUBLE_BE)
	                "b"
#elif defined(DUK_USE_DOUBLE_ME)
	                "m"
#else
	                "?"
#endif
	                " "
			/* Packed or unpacked tval */
#if defined(DUK_USE_PACKED_TVAL)
	                "p"
#else
	                "u"
#endif
#if defined(DUK_USE_FASTINT)
			"f"
#endif
			" "
			/* Low memory/performance options */
#if defined(DUK_USE_STRTAB_PTRCOMP)
			"s"
#endif
#if !defined(DUK_USE_HEAPPTR16) && !defined(DUK_DATAPTR16) && !defined(DUK_FUNCPTR16)
			"n"
#endif
#if defined(DUK_USE_HEAPPTR16)
			"h"
#endif
#if defined(DUK_USE_DATAPTR16)
			"d"
#endif
#if defined(DUK_USE_FUNCPTR16)
			"f"
#endif
#if defined(DUK_USE_REFCOUNT16)
			"R"
#endif
#if defined(DUK_USE_STRHASH16)
			"H"
#endif
#if defined(DUK_USE_STRLEN16)
			"S"
#endif
#if defined(DUK_USE_BUFLEN16)
			"B"
#endif
#if defined(DUK_USE_OBJSIZES16)
			"O"
#endif
#if defined(DUK_USE_LIGHTFUNC_BUILTINS)
			"L"
#endif
#if defined(DUK_USE_ROM_STRINGS) || defined(DUK_USE_ROM_OBJECTS)
			/* XXX: This won't be shown in practice now
			 * because this code is not run when builtins
			 * are in ROM.
			 */
			"Z"
#endif
#if defined(DUK_USE_LITCACHE_SIZE)
			"l"
#endif
	                " "
			/* Object property allocation layout */
#if defined(DUK_USE_HOBJECT_LAYOUT_1)
			"p1"
#elif defined(DUK_USE_HOBJECT_LAYOUT_2)
			"p2"
#elif defined(DUK_USE_HOBJECT_LAYOUT_3)
			"p3"
#else
			"p?"
#endif
			" "
			/* Alignment guarantee */
#if (DUK_USE_ALIGN_BY == 4)
			"a4"
#elif (DUK_USE_ALIGN_BY == 8)
			"a8"
#elif (DUK_USE_ALIGN_BY == 1)
			"a1"
#else
#error invalid DUK_USE_ALIGN_BY
#endif
			" "
			/* Architecture, OS, and compiler strings */
	                DUK_USE_ARCH_STRING
			" "
	                DUK_USE_OS_STRING
			" "
	                DUK_USE_COMPILER_STRING);
	duk_xdef_prop_stridx_short(thr, DUK_BIDX_DUKTAPE, DUK_STRIDX_ENV, DUK_PROPDESC_FLAGS_WC);

	/*
	 *  Since built-ins are not often extended, compact them.
	 */

	DUK_DD(DUK_DDPRINT("compact built-ins"));
	for (i = 0; i < DUK_NUM_ALL_BUILTINS; i++) {
		duk_hobject_compact_props(thr, duk_known_hobject(thr, (duk_idx_t) i));
	}

	DUK_D(DUK_DPRINT("INITBUILTINS END"));

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 1)
	for (i = 0; i < DUK_NUM_ALL_BUILTINS; i++) {
		DUK_DD(DUK_DDPRINT("built-in object %ld after initialization and compacting: %!@iO",
		                   (long) i, (duk_heaphdr *) duk_require_hobject(thr, (duk_idx_t) i)));
	}
#endif

	/*
	 *  Pop built-ins from stack: they are now INCREF'd and
	 *  reachable from the builtins[] array or indirectly
	 *  through builtins[].
	 */

	duk_set_top(thr, 0);
	DUK_ASSERT_TOP(thr, 0);
}
#endif  /* DUK_USE_ROM_OBJECTS */

DUK_INTERNAL void duk_hthread_copy_builtin_objects(duk_hthread *thr_from, duk_hthread *thr_to) {
	duk_small_uint_t i;

	for (i = 0; i < DUK_NUM_BUILTINS; i++) {
		thr_to->builtins[i] = thr_from->builtins[i];
		DUK_HOBJECT_INCREF_ALLOWNULL(thr_to, thr_to->builtins[i]);  /* side effect free */
	}
}

/* automatic undefs */
#undef DUK__LENGTH_PROP_BITS
#undef DUK__NARGS_BITS
#undef DUK__NARGS_VARARGS_MARKER
#undef DUK__PROP_FLAGS_BITS
#undef DUK__PROP_TYPE_ACCESSOR
#undef DUK__PROP_TYPE_BITS
#undef DUK__PROP_TYPE_BOOLEAN_FALSE
#undef DUK__PROP_TYPE_BOOLEAN_TRUE
#undef DUK__PROP_TYPE_BUILTIN
#undef DUK__PROP_TYPE_DOUBLE
#undef DUK__PROP_TYPE_STRIDX
#undef DUK__PROP_TYPE_STRING
#undef DUK__PROP_TYPE_UNDEFINED
/*
 *  Thread support.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL void duk_hthread_terminate(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);

	while (thr->callstack_curr != NULL) {
		duk_hthread_activation_unwind_norz(thr);
	}

	thr->valstack_bottom = thr->valstack;
	duk_set_top(thr, 0);  /* unwinds valstack, updating refcounts */

	thr->state = DUK_HTHREAD_STATE_TERMINATED;

	/* Here we could remove references to built-ins, but it may not be
	 * worth the effort because built-ins are quite likely to be shared
	 * with another (unterminated) thread, and terminated threads are also
	 * usually garbage collected quite quickly.
	 *
	 * We could also shrink the value stack here, but that also may not
	 * be worth the effort for the same reason.
	 */

	DUK_REFZERO_CHECK_SLOW(thr);
}

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL duk_uint_fast32_t duk_hthread_get_act_curr_pc(duk_hthread *thr, duk_activation *act) {
	duk_instr_t *bcode;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_UNREF(thr);

	/* XXX: store 'bcode' pointer to activation for faster lookup? */
	if (act->func && DUK_HOBJECT_IS_COMPFUNC(act->func)) {
		bcode = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) (act->func));
		return (duk_uint_fast32_t) (act->curr_pc - bcode);
	}
	return 0;
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

DUK_INTERNAL duk_uint_fast32_t duk_hthread_get_act_prev_pc(duk_hthread *thr, duk_activation *act) {
	duk_instr_t *bcode;
	duk_uint_fast32_t ret;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_UNREF(thr);

	if (act->func && DUK_HOBJECT_IS_COMPFUNC(act->func)) {
		bcode = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) (act->func));
		ret = (duk_uint_fast32_t) (act->curr_pc - bcode);
		if (ret > 0) {
			ret--;
		}
		return ret;
	}
	return 0;
}

/* Write bytecode executor's curr_pc back to topmost activation (if any). */
DUK_INTERNAL void duk_hthread_sync_currpc(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT(thr != NULL);

	if (thr->ptr_curr_pc != NULL) {
		/* ptr_curr_pc != NULL only when bytecode executor is active. */
		DUK_ASSERT(thr->callstack_top > 0);
		DUK_ASSERT(thr->callstack_curr != NULL);
		act = thr->callstack_curr;
		DUK_ASSERT(act != NULL);
		act->curr_pc = *thr->ptr_curr_pc;
	}
}

DUK_INTERNAL void duk_hthread_sync_and_null_currpc(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT(thr != NULL);

	if (thr->ptr_curr_pc != NULL) {
		/* ptr_curr_pc != NULL only when bytecode executor is active. */
		DUK_ASSERT(thr->callstack_top > 0);
		DUK_ASSERT(thr->callstack_curr != NULL);
		act = thr->callstack_curr;
		DUK_ASSERT(act != NULL);
		act->curr_pc = *thr->ptr_curr_pc;
		thr->ptr_curr_pc = NULL;
	}
}
/*
 *  Thread stack (mainly call stack) primitives: allocation of activations,
 *  unwinding catchers and activations, etc.
 *
 *  Value stack handling is a part of the API implementation.
 */

/* #include duk_internal.h -> already included */

/* Unwind the topmost catcher of the current activation (caller must check that
 * both exist) without side effects.
 */
DUK_INTERNAL void duk_hthread_catcher_unwind_norz(duk_hthread *thr, duk_activation *act) {
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(act->cat != NULL);  /* caller must check */
	cat = act->cat;
	DUK_ASSERT(cat != NULL);

	DUK_DDD(DUK_DDDPRINT("unwinding catch stack entry %p (lexenv check is done)", (void *) cat));

	if (DUK_CAT_HAS_LEXENV_ACTIVE(cat)) {
		duk_hobject *env;

		env = act->lex_env;             /* current lex_env of the activation (created for catcher) */
		DUK_ASSERT(env != NULL);        /* must be, since env was created when catcher was created */
		act->lex_env = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, env);  /* prototype is lex_env before catcher created */
		DUK_HOBJECT_INCREF(thr, act->lex_env);
		DUK_HOBJECT_DECREF_NORZ(thr, env);

		/* There is no need to decref anything else than 'env': if 'env'
		 * becomes unreachable, refzero will handle decref'ing its prototype.
		 */
	}

	act->cat = cat->parent;
	duk_hthread_catcher_free(thr, cat);
}

/* Same as above, but caller is certain no catcher-related lexenv may exist. */
DUK_INTERNAL void duk_hthread_catcher_unwind_nolexenv_norz(duk_hthread *thr, duk_activation *act) {
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(act->cat != NULL);  /* caller must check */
	cat = act->cat;
	DUK_ASSERT(cat != NULL);

	DUK_DDD(DUK_DDDPRINT("unwinding catch stack entry %p (lexenv check is not done)", (void *) cat));

	DUK_ASSERT(!DUK_CAT_HAS_LEXENV_ACTIVE(cat));

	act->cat = cat->parent;
	duk_hthread_catcher_free(thr, cat);
}

DUK_LOCAL
#if defined(DUK_USE_CACHE_CATCHER)
DUK_NOINLINE
#endif
duk_catcher *duk__hthread_catcher_alloc_slow(duk_hthread *thr) {
	duk_catcher *cat;

	cat = (duk_catcher *) DUK_ALLOC_CHECKED(thr, sizeof(duk_catcher));
	DUK_ASSERT(cat != NULL);
	return cat;
}

#if defined(DUK_USE_CACHE_CATCHER)
DUK_INTERNAL DUK_INLINE duk_catcher *duk_hthread_catcher_alloc(duk_hthread *thr) {
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);

	cat = thr->heap->catcher_free;
	if (DUK_LIKELY(cat != NULL)) {
		thr->heap->catcher_free = cat->parent;
		return cat;
	}

	return duk__hthread_catcher_alloc_slow(thr);
}
#else  /* DUK_USE_CACHE_CATCHER */
DUK_INTERNAL duk_catcher *duk_hthread_catcher_alloc(duk_hthread *thr) {
	return duk__hthread_catcher_alloc_slow(thr);
}
#endif  /* DUK_USE_CACHE_CATCHER */

DUK_INTERNAL void duk_hthread_catcher_free(duk_hthread *thr, duk_catcher *cat) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(cat != NULL);

#if defined(DUK_USE_CACHE_CATCHER)
	/* Unconditional caching for now; freed in mark-and-sweep. */
	cat->parent = thr->heap->catcher_free;
	thr->heap->catcher_free = cat;
#else
	DUK_FREE_CHECKED(thr, (void *) cat);
#endif
}

DUK_LOCAL
#if defined(DUK_USE_CACHE_ACTIVATION)
DUK_NOINLINE
#endif
duk_activation *duk__hthread_activation_alloc_slow(duk_hthread *thr) {
	duk_activation *act;

	act = (duk_activation *) DUK_ALLOC_CHECKED(thr, sizeof(duk_activation));
	DUK_ASSERT(act != NULL);
	return act;
}

#if defined(DUK_USE_CACHE_ACTIVATION)
DUK_INTERNAL DUK_INLINE duk_activation *duk_hthread_activation_alloc(duk_hthread *thr) {
	duk_activation *act;

	DUK_ASSERT(thr != NULL);

	act = thr->heap->activation_free;
	if (DUK_LIKELY(act != NULL)) {
		thr->heap->activation_free = act->parent;
		return act;
	}

	return duk__hthread_activation_alloc_slow(thr);
}
#else  /* DUK_USE_CACHE_ACTIVATION */
DUK_INTERNAL duk_activation *duk_hthread_activation_alloc(duk_hthread *thr) {
	return duk__hthread_activation_alloc_slow(thr);
}
#endif  /* DUK_USE_CACHE_ACTIVATION */


DUK_INTERNAL void duk_hthread_activation_free(duk_hthread *thr, duk_activation *act) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);

#if defined(DUK_USE_CACHE_ACTIVATION)
	/* Unconditional caching for now; freed in mark-and-sweep. */
	act->parent = thr->heap->activation_free;
	thr->heap->activation_free = act;
#else
	DUK_FREE_CHECKED(thr, (void *) act);
#endif
}

/* Internal helper: process the unwind for the topmost activation of a thread,
 * but leave the duk_activation in place for possible tailcall reuse.
 */
DUK_LOCAL void duk__activation_unwind_nofree_norz(duk_hthread *thr) {
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_heap *heap;
#endif
	duk_activation *act;
	duk_hobject *func;
	duk_hobject *tmp;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->callstack_curr != NULL);  /* caller must check */
	DUK_ASSERT(thr->callstack_top > 0);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	/* With lightfuncs, act 'func' may be NULL. */

	/* With duk_activation records allocated separately, 'act' is a stable
	 * pointer and not affected by side effects.
	 */

#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	/*
	 *  Restore 'caller' property for non-strict callee functions.
	 */

	func = DUK_ACT_GET_FUNC(act);
	if (func != NULL && !DUK_HOBJECT_HAS_STRICT(func)) {
		duk_tval *tv_caller;
		duk_tval tv_tmp;
		duk_hobject *h_tmp;

		tv_caller = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, func, DUK_STRIDX_CALLER);

		/* The act->prev_caller should only be set if the entry for 'caller'
		 * exists (as it is only set in that case, and the property is not
		 * configurable), but handle all the cases anyway.
		 */

		if (tv_caller) {
			DUK_TVAL_SET_TVAL(&tv_tmp, tv_caller);
			if (act->prev_caller) {
				/* Just transfer the refcount from act->prev_caller to tv_caller,
				 * so no need for a refcount update.  This is the expected case.
				 */
				DUK_TVAL_SET_OBJECT(tv_caller, act->prev_caller);
				act->prev_caller = NULL;
			} else {
				DUK_TVAL_SET_NULL(tv_caller);   /* no incref needed */
				DUK_ASSERT(act->prev_caller == NULL);
			}
			DUK_TVAL_DECREF_NORZ(thr, &tv_tmp);
		} else {
			h_tmp = act->prev_caller;
			if (h_tmp) {
				act->prev_caller = NULL;
				DUK_HOBJECT_DECREF_NORZ(thr, h_tmp);
			}
		}
		DUK_ASSERT(act->prev_caller == NULL);
	}
#endif

	/*
	 *  Unwind debugger state.  If we unwind while stepping
	 *  (for any step type), pause execution.  This is the
	 *  only place explicitly handling a step out.
	 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	heap = thr->heap;
	if (heap->dbg_pause_act == thr->callstack_curr) {
		if (heap->dbg_pause_flags & DUK_PAUSE_FLAG_FUNC_EXIT) {
			DUK_D(DUK_DPRINT("PAUSE TRIGGERED by function exit"));
			duk_debug_set_paused(heap);
		} else {
			DUK_D(DUK_DPRINT("unwound past dbg_pause_act, set to NULL"));
			heap->dbg_pause_act = NULL;  /* avoid stale pointers */
		}
		DUK_ASSERT(heap->dbg_pause_act == NULL);
	}
#endif

	/*
	 *  Unwind catchers.
	 *
	 *  Since there are no references in the catcher structure,
	 *  unwinding is quite simple.  The only thing we need to
	 *  look out for is popping a possible lexical environment
	 *  established for an active catch clause.
	 */

	while (act->cat != NULL) {
		duk_hthread_catcher_unwind_norz(thr, act);
	}

	/*
	 *  Close environment record(s) if they exist.
	 *
	 *  Only variable environments are closed.  If lex_env != var_env, it
	 *  cannot currently contain any register bound declarations.
	 *
	 *  Only environments created for a NEWENV function are closed.  If an
	 *  environment is created for e.g. an eval call, it must not be closed.
	 */

	func = DUK_ACT_GET_FUNC(act);
	if (func != NULL && !DUK_HOBJECT_HAS_NEWENV(func)) {
		DUK_DDD(DUK_DDDPRINT("skip closing environments, envs not owned by this activation"));
		goto skip_env_close;
	}
	/* func is NULL for lightfunc */

	/* Catch sites are required to clean up their environments
	 * in FINALLY part before propagating, so this should
	 * always hold here.
	 */
	DUK_ASSERT(act->lex_env == act->var_env);

	/* XXX: Closing the environment record copies values from registers
	 * into the scope object.  It's side effect free as such, but may
	 * currently run out of memory which causes an error throw.  This is
	 * an actual sandboxing problem for error unwinds, and needs to be
	 * fixed e.g. by preallocating the scope property slots.
	 */
	if (act->var_env != NULL) {
		DUK_DDD(DUK_DDDPRINT("closing var_env record %p -> %!O",
		                     (void *) act->var_env, (duk_heaphdr *) act->var_env));
		duk_js_close_environment_record(thr, act->var_env);
	}

 skip_env_close:

	/*
	 *  Update preventcount
	 */

	if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
		DUK_ASSERT(thr->callstack_preventcount >= 1);
		thr->callstack_preventcount--;
	}

	/*
	 *  Reference count updates, using NORZ macros so we don't
	 *  need to handle side effects.
	 *
	 *  duk_activation pointers like act->var_env are intentionally
	 *  left as garbage and not NULLed.  Without side effects they
	 *  can't be used when the values are dangling/garbage.
	 */

	DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, act->var_env);
	DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, act->lex_env);
	tmp = DUK_ACT_GET_FUNC(act);
	DUK_HOBJECT_DECREF_NORZ_ALLOWNULL(thr, tmp);
	DUK_UNREF(tmp);
}

/* Unwind topmost duk_activation of a thread, caller must ensure that an
 * activation exists.  The call is side effect free, except that scope
 * closure may currently throw an out-of-memory error.
 */
DUK_INTERNAL void duk_hthread_activation_unwind_norz(duk_hthread *thr) {
	duk_activation *act;

	duk__activation_unwind_nofree_norz(thr);

	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(thr->callstack_top > 0);
	act = thr->callstack_curr;
	thr->callstack_curr = act->parent;
	thr->callstack_top--;

	/* Ideally we'd restore value stack reserve here to caller's value.
	 * This doesn't work for current unwind call sites however, because
	 * the current (unwound) value stack top may be above the reserve.
	 * Thus value stack reserve is restored by the call sites.
	 */

	/* XXX: inline for performance builds? */
	duk_hthread_activation_free(thr, act);

	/* We could clear the book-keeping variables like retval_byteoff for
	 * the topmost activation, but don't do so now as it's not necessary.
	 */
}

DUK_INTERNAL void duk_hthread_activation_unwind_reuse_norz(duk_hthread *thr) {
	duk__activation_unwind_nofree_norz(thr);
}

/* Get duk_activation for given callstack level or NULL if level is invalid
 * or deeper than the call stack.  Level -1 refers to current activation, -2
 * to its caller, etc.  Starting from Duktape 2.2 finding the activation is
 * a linked list scan which gets more expensive the deeper the lookup is.
 */
DUK_INTERNAL duk_activation *duk_hthread_get_activation_for_level(duk_hthread *thr, duk_int_t level) {
	duk_activation *act;

	if (level >= 0) {
		return NULL;
	}
	act = thr->callstack_curr;
	for (;;) {
		if (act == NULL) {
			return act;
		}
		if (level == -1) {
			return act;
		}
		level++;
		act = act->parent;
	}
	/* never here */
}

#if defined(DUK_USE_FINALIZER_TORTURE)
DUK_INTERNAL void duk_hthread_valstack_torture_realloc(duk_hthread *thr) {
	duk_size_t alloc_size;
	duk_tval *new_ptr;
	duk_ptrdiff_t alloc_end_off;
	duk_ptrdiff_t end_off;
	duk_ptrdiff_t bottom_off;
	duk_ptrdiff_t top_off;

	if (thr->valstack == NULL) {
		DUK_D(DUK_DPRINT("skip valstack torture realloc, valstack is NULL"));
		return;
	}

	alloc_end_off = (duk_ptrdiff_t) ((duk_uint8_t *) thr->valstack_alloc_end - (duk_uint8_t *) thr->valstack);
	end_off = (duk_ptrdiff_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
	bottom_off = (duk_ptrdiff_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack);
	top_off = (duk_ptrdiff_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) thr->valstack);
	alloc_size = (duk_size_t) alloc_end_off;
	if (alloc_size == 0) {
		DUK_D(DUK_DPRINT("skip valstack torture realloc, alloc_size is zero"));
		return;
	}

	/* Use DUK_ALLOC_RAW() to avoid side effects. */
	new_ptr = (duk_tval *) DUK_ALLOC_RAW(thr->heap, alloc_size);
	if (new_ptr != NULL) {
		duk_memcpy((void *) new_ptr, (const void *) thr->valstack, alloc_size);
		duk_memset((void *) thr->valstack, 0x55, alloc_size);
		DUK_FREE_CHECKED(thr, (void *) thr->valstack);
		thr->valstack = new_ptr;
		thr->valstack_alloc_end = (duk_tval *) ((duk_uint8_t *) new_ptr + alloc_end_off);
		thr->valstack_end = (duk_tval *) ((duk_uint8_t *) new_ptr + end_off);
		thr->valstack_bottom = (duk_tval *) ((duk_uint8_t *) new_ptr + bottom_off);
		thr->valstack_top = (duk_tval *) ((duk_uint8_t *) new_ptr + top_off);
	} else {
		DUK_D(DUK_DPRINT("failed to realloc valstack for torture, ignore"));
	}
}
#endif  /* DUK_USE_FINALIZER_TORTURE */
/*
 *  Shared helpers for arithmetic operations
 */

/* #include duk_internal.h -> already included */

/* ECMAScript modulus ('%') does not match IEEE 754 "remainder" operation
 * (implemented by remainder() in C99) but does seem to match ANSI C fmod().
 * Compare E5 Section 11.5.3 and "man fmod".
 */
DUK_INTERNAL double duk_js_arith_mod(double d1, double d2) {
#if defined(DUK_USE_POW_WORKAROUNDS)
	/* Specific fixes to common fmod() implementation issues:
	 * - test-bug-mingw-math-issues.js
	 */
	if (DUK_ISINF(d2)) {
		if (DUK_ISINF(d1)) {
			return DUK_DOUBLE_NAN;
		} else {
			return d1;
		}
	} else if (duk_double_equals(d1, 0.0)) {
		/* d1 +/-0 is returned as is (preserving sign) except when
		 * d2 is zero or NaN.
		 */
		if (duk_double_equals(d2, 0.0) || DUK_ISNAN(d2)) {
			return DUK_DOUBLE_NAN;
		} else {
			return d1;
		}
	}
#else
	/* Some ISO C assumptions. */
	DUK_ASSERT(duk_double_equals(DUK_FMOD(1.0, DUK_DOUBLE_INFINITY), 1.0));
	DUK_ASSERT(duk_double_equals(DUK_FMOD(-1.0, DUK_DOUBLE_INFINITY), -1.0));
	DUK_ASSERT(duk_double_equals(DUK_FMOD(1.0, -DUK_DOUBLE_INFINITY), 1.0));
	DUK_ASSERT(duk_double_equals(DUK_FMOD(-1.0, -DUK_DOUBLE_INFINITY), -1.0));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(DUK_DOUBLE_INFINITY, DUK_DOUBLE_INFINITY)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(DUK_DOUBLE_INFINITY, -DUK_DOUBLE_INFINITY)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(-DUK_DOUBLE_INFINITY, DUK_DOUBLE_INFINITY)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(-DUK_DOUBLE_INFINITY, -DUK_DOUBLE_INFINITY)));
	DUK_ASSERT(duk_double_equals(DUK_FMOD(0.0, 1.0), 0.0) && DUK_SIGNBIT(DUK_FMOD(0.0, 1.0)) == 0);
	DUK_ASSERT(duk_double_equals(DUK_FMOD(-0.0, 1.0), 0.0) && DUK_SIGNBIT(DUK_FMOD(-0.0, 1.0)) != 0);
	DUK_ASSERT(duk_double_equals(DUK_FMOD(0.0, DUK_DOUBLE_INFINITY), 0.0) && DUK_SIGNBIT(DUK_FMOD(0.0, DUK_DOUBLE_INFINITY)) == 0);
	DUK_ASSERT(duk_double_equals(DUK_FMOD(-0.0, DUK_DOUBLE_INFINITY), 0.0) && DUK_SIGNBIT(DUK_FMOD(-0.0, DUK_DOUBLE_INFINITY)) != 0);
	DUK_ASSERT(duk_double_equals(DUK_FMOD(0.0, -DUK_DOUBLE_INFINITY), 0.0) && DUK_SIGNBIT(DUK_FMOD(0.0, DUK_DOUBLE_INFINITY)) == 0);
	DUK_ASSERT(duk_double_equals(DUK_FMOD(-0.0, -DUK_DOUBLE_INFINITY), 0.0) && DUK_SIGNBIT(DUK_FMOD(-0.0, -DUK_DOUBLE_INFINITY)) != 0);
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(0.0, 0.0)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(-0.0, 0.0)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(0.0, -0.0)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(-0.0, -0.0)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(0.0, DUK_DOUBLE_NAN)));
	DUK_ASSERT(DUK_ISNAN(DUK_FMOD(-0.0, DUK_DOUBLE_NAN)));
#endif

	return (duk_double_t) DUK_FMOD((double) d1, (double) d2);
}

/* Shared helper for Math.pow() and exponentiation operator. */
DUK_INTERNAL double duk_js_arith_pow(double x, double y) {
	/* The ANSI C pow() semantics differ from ECMAScript.
	 *
	 * E.g. when x==1 and y is +/- infinite, the ECMAScript required
	 * result is NaN, while at least Linux pow() returns 1.
	 */

	duk_small_int_t cx, cy, sx;

	DUK_UNREF(cx);
	DUK_UNREF(sx);
	cy = (duk_small_int_t) DUK_FPCLASSIFY(y);

	if (cy == DUK_FP_NAN) {
		goto ret_nan;
	}
	if (duk_double_equals(DUK_FABS(x), 1.0) && cy == DUK_FP_INFINITE) {
		goto ret_nan;
	}

#if defined(DUK_USE_POW_WORKAROUNDS)
	/* Specific fixes to common pow() implementation issues:
	 *   - test-bug-netbsd-math-pow.js: NetBSD 6.0 on x86 (at least)
	 *   - test-bug-mingw-math-issues.js
	 */
	cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
	if (cx == DUK_FP_ZERO && y < 0.0) {
		sx = (duk_small_int_t) DUK_SIGNBIT(x);
		if (sx == 0) {
			/* Math.pow(+0,y) should be Infinity when y<0.  NetBSD pow()
			 * returns -Infinity instead when y is <0 and finite.  The
			 * if-clause also catches y == -Infinity (which works even
			 * without the fix).
			 */
			return DUK_DOUBLE_INFINITY;
		} else {
			/* Math.pow(-0,y) where y<0 should be:
			 *   - -Infinity if y<0 and an odd integer
			 *   - Infinity if y<0 but not an odd integer
			 * NetBSD pow() returns -Infinity for all finite y<0.  The
			 * if-clause also catches y == -Infinity (which works even
			 * without the fix).
			 */

			/* fmod() return value has same sign as input (negative) so
			 * the result here will be in the range ]-2,0], -1 indicates
			 * odd.  If x is -Infinity, NaN is returned and the odd check
			 * always concludes "not odd" which results in desired outcome.
			 */
			double tmp = DUK_FMOD(y, 2);
			if (tmp == -1.0) {
				return -DUK_DOUBLE_INFINITY;
			} else {
				/* Not odd, or y == -Infinity */
				return DUK_DOUBLE_INFINITY;
			}
		}
	} else if (cx == DUK_FP_NAN) {
		if (duk_double_equals(y, 0.0)) {
			/* NaN ** +/- 0 should always be 1, but is NaN on
			 * at least some Cygwin/MinGW versions.
			 */
			return 1.0;
		}
	}
#else
	/* Some ISO C assumptions. */
	DUK_ASSERT(duk_double_equals(DUK_POW(DUK_DOUBLE_NAN, 0.0), 1.0));
	DUK_ASSERT(DUK_ISINF(DUK_POW(0.0, -1.0)) && DUK_SIGNBIT(DUK_POW(0.0, -1.0)) == 0);
	DUK_ASSERT(DUK_ISINF(DUK_POW(-0.0, -2.0)) && DUK_SIGNBIT(DUK_POW(-0.0, -2.0)) == 0);
	DUK_ASSERT(DUK_ISINF(DUK_POW(-0.0, -3.0)) && DUK_SIGNBIT(DUK_POW(-0.0, -3.0)) != 0);
#endif

	return DUK_POW(x, y);

 ret_nan:
	return DUK_DOUBLE_NAN;
}
/*
 *  Call handling.
 *
 *  duk_handle_call_unprotected():
 *
 *    - Unprotected call to ECMAScript or Duktape/C function, from native
 *      code or bytecode executor.
 *
 *    - Also handles Ecma-to-Ecma calls which reuses a currently running
 *      executor instance to avoid native recursion.  Call setup is done
 *      normally, but just before calling the bytecode executor a special
 *      return code is used to indicate that a calling executor is reused.
 *
 *    - Also handles tailcalls, i.e. reuse of current duk_activation.
 *
 *    - Also handles setup for initial Duktape.Thread.resume().
 *
 *  duk_handle_safe_call():
 *
 *    - Protected C call within current activation.
 *
 *  setjmp() and local variables have a nasty interaction, see execution.rst;
 *  non-volatile locals modified after setjmp() call are not guaranteed to
 *  keep their value and can cause compiler or compiler version specific
 *  difficult to replicate issues.
 *
 *  See 'execution.rst'.
 */

/* #include duk_internal.h -> already included */

/* XXX: heap->error_not_allowed for success path too? */

/*
 *  Limit check helpers.
 */

/* Check native stack space if DUK_USE_NATIVE_STACK_CHECK() defined. */
DUK_INTERNAL void duk_native_stack_check(duk_hthread *thr) {
#if defined(DUK_USE_NATIVE_STACK_CHECK)
	if (DUK_USE_NATIVE_STACK_CHECK() != 0) {
		DUK_ERROR_RANGE(thr, DUK_STR_NATIVE_STACK_LIMIT);
	}
#else
	DUK_UNREF(thr);
#endif
}

/* Allow headroom for calls during error augmentation (see GH-191).
 * We allow space for 10 additional recursions, with one extra
 * for, e.g. a print() call at the deepest level, and an extra
 * +1 for protected call wrapping.
 */
#define DUK__AUGMENT_CALL_RELAX_COUNT  (10 + 2)

/* Stack space required by call handling entry. */
#define DUK__CALL_HANDLING_REQUIRE_STACK  8

DUK_LOCAL DUK_NOINLINE void duk__call_c_recursion_limit_check_slowpath(duk_hthread *thr) {
	/* When augmenting an error, the effective limit is a bit higher.
	 * Check for it only if the fast path check fails.
	 */
#if defined(DUK_USE_AUGMENT_ERROR_THROW) || defined(DUK_USE_AUGMENT_ERROR_CREATE)
	if (thr->heap->augmenting_error) {
		if (thr->heap->call_recursion_depth < thr->heap->call_recursion_limit + DUK__AUGMENT_CALL_RELAX_COUNT) {
			DUK_D(DUK_DPRINT("C recursion limit reached but augmenting error and within relaxed limit"));
			return;
		}
	}
#endif

	DUK_D(DUK_DPRINT("call prevented because C recursion limit reached"));
	DUK_ERROR_RANGE(thr, DUK_STR_NATIVE_STACK_LIMIT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL DUK_ALWAYS_INLINE void duk__call_c_recursion_limit_check(duk_hthread *thr) {
	DUK_ASSERT(thr->heap->call_recursion_depth >= 0);
	DUK_ASSERT(thr->heap->call_recursion_depth <= thr->heap->call_recursion_limit);

	duk_native_stack_check(thr);

	/* This check is forcibly inlined because it's very cheap and almost
	 * always passes.  The slow path is forcibly noinline.
	 */
	if (DUK_LIKELY(thr->heap->call_recursion_depth < thr->heap->call_recursion_limit)) {
		return;
	}

	duk__call_c_recursion_limit_check_slowpath(thr);
}

DUK_LOCAL DUK_NOINLINE void duk__call_callstack_limit_check_slowpath(duk_hthread *thr) {
	/* When augmenting an error, the effective limit is a bit higher.
	 * Check for it only if the fast path check fails.
	 */
#if defined(DUK_USE_AUGMENT_ERROR_THROW) || defined(DUK_USE_AUGMENT_ERROR_CREATE)
	if (thr->heap->augmenting_error) {
		if (thr->callstack_top < DUK_USE_CALLSTACK_LIMIT + DUK__AUGMENT_CALL_RELAX_COUNT) {
			DUK_D(DUK_DPRINT("call stack limit reached but augmenting error and within relaxed limit"));
			return;
		}
	}
#endif

	/* XXX: error message is a bit misleading: we reached a recursion
	 * limit which is also essentially the same as a C callstack limit
	 * (except perhaps with some relaxed threading assumptions).
	 */
	DUK_D(DUK_DPRINT("call prevented because call stack limit reached"));
	DUK_ERROR_RANGE(thr, DUK_STR_CALLSTACK_LIMIT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL DUK_ALWAYS_INLINE void duk__call_callstack_limit_check(duk_hthread *thr) {
	/* This check is forcibly inlined because it's very cheap and almost
	 * always passes.  The slow path is forcibly noinline.
	 */
	if (DUK_LIKELY(thr->callstack_top < DUK_USE_CALLSTACK_LIMIT)) {
		return;
	}

	duk__call_callstack_limit_check_slowpath(thr);
}

/*
 *  Interrupt counter fixup (for development only).
 */

#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
DUK_LOCAL void duk__interrupt_fixup(duk_hthread *thr, duk_hthread *entry_curr_thread) {
	/* Currently the bytecode executor and executor interrupt
	 * instruction counts are off because we don't execute the
	 * interrupt handler when we're about to exit from the initial
	 * user call into Duktape.
	 *
	 * If we were to execute the interrupt handler here, the counts
	 * would match.  You can enable this block manually to check
	 * that this is the case.
	 */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);

#if defined(DUK_USE_INTERRUPT_DEBUG_FIXUP)
	if (entry_curr_thread == NULL) {
		thr->interrupt_init = thr->interrupt_init - thr->interrupt_counter;
		thr->heap->inst_count_interrupt += thr->interrupt_init;
		DUK_DD(DUK_DDPRINT("debug test: updated interrupt count on exit to "
		                   "user code, instruction counts: executor=%ld, interrupt=%ld",
		                   (long) thr->heap->inst_count_exec, (long) thr->heap->inst_count_interrupt));
		DUK_ASSERT(thr->heap->inst_count_exec == thr->heap->inst_count_interrupt);
	}
#else
	DUK_UNREF(thr);
	DUK_UNREF(entry_curr_thread);
#endif
}
#endif

/*
 *  Arguments object creation.
 *
 *  Creating arguments objects involves many small details, see E5 Section
 *  10.6 for the specific requirements.  Much of the arguments object exotic
 *  behavior is implemented in duk_hobject_props.c, and is enabled by the
 *  object flag DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS.
 */

DUK_LOCAL void duk__create_arguments_object(duk_hthread *thr,
                                            duk_hobject *func,
                                            duk_hobject *varenv,
                                            duk_idx_t idx_args) {
	duk_hobject *arg;          /* 'arguments' */
	duk_hobject *formals;      /* formals for 'func' (may be NULL if func is a C function) */
	duk_idx_t i_arg;
	duk_idx_t i_map;
	duk_idx_t i_mappednames;
	duk_idx_t i_formals;
	duk_idx_t i_argbase;
	duk_idx_t n_formals;
	duk_idx_t idx;
	duk_idx_t num_stack_args;
	duk_bool_t need_map;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_NONBOUND_FUNCTION(func));
	DUK_ASSERT(varenv != NULL);

	/* [ ... func this arg1(@idx_args) ... argN envobj ]
	 * [ arg1(@idx_args) ... argN envobj ] (for tailcalls)
	 */

	need_map = 0;

	i_argbase = idx_args;
	num_stack_args = duk_get_top(thr) - i_argbase - 1;
	DUK_ASSERT(i_argbase >= 0);
	DUK_ASSERT(num_stack_args >= 0);

	formals = (duk_hobject *) duk_hobject_get_formals(thr, (duk_hobject *) func);
	if (formals) {
		n_formals = (duk_idx_t) ((duk_harray *) formals)->length;
		duk_push_hobject(thr, formals);
	} else {
		/* This shouldn't happen without tampering of internal
		 * properties: if a function accesses 'arguments', _Formals
		 * is kept.  Check for the case anyway in case internal
		 * properties have been modified manually.
		 */
		DUK_D(DUK_DPRINT("_Formals is undefined when creating arguments, use n_formals == 0"));
		n_formals = 0;
		duk_push_undefined(thr);
	}
	i_formals = duk_require_top_index(thr);

	DUK_ASSERT(n_formals >= 0);
	DUK_ASSERT(formals != NULL || n_formals == 0);

	DUK_DDD(DUK_DDDPRINT("func=%!O, formals=%!O, n_formals=%ld",
	                     (duk_heaphdr *) func, (duk_heaphdr *) formals,
	                     (long) n_formals));

	/* [ ... formals ] */

	/*
	 *  Create required objects:
	 *    - 'arguments' object: array-like, but not an array
	 *    - 'map' object: internal object, tied to 'arguments' (bare)
	 *    - 'mappedNames' object: temporary value used during construction (bare)
	 */

	arg = duk_push_object_helper(thr,
	                             DUK_HOBJECT_FLAG_EXTENSIBLE |
	                             DUK_HOBJECT_FLAG_FASTREFS |
	                             DUK_HOBJECT_FLAG_ARRAY_PART |
	                             DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARGUMENTS),
	                             DUK_BIDX_OBJECT_PROTOTYPE);
	DUK_ASSERT(arg != NULL);
	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                              -1);  /* no prototype */
	(void) duk_push_object_helper(thr,
	                              DUK_HOBJECT_FLAG_EXTENSIBLE |
	                              DUK_HOBJECT_FLAG_FASTREFS |
	                              DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                              -1);  /* no prototype */
	i_arg = duk_get_top(thr) - 3;
	i_map = i_arg + 1;
	i_mappednames = i_arg + 2;
	DUK_ASSERT(!duk_is_bare_object(thr, -3));  /* arguments */
	DUK_ASSERT(duk_is_bare_object(thr, -2));  /* map */
	DUK_ASSERT(duk_is_bare_object(thr, -1));  /* mappedNames */

	/* [ ... formals arguments map mappedNames ] */

	DUK_DDD(DUK_DDDPRINT("created arguments related objects: "
	                     "arguments at index %ld -> %!O "
	                     "map at index %ld -> %!O "
	                     "mappednames at index %ld -> %!O",
	                     (long) i_arg, (duk_heaphdr *) duk_get_hobject(thr, i_arg),
	                     (long) i_map, (duk_heaphdr *) duk_get_hobject(thr, i_map),
	                     (long) i_mappednames, (duk_heaphdr *) duk_get_hobject(thr, i_mappednames)));

	/*
	 *  Init arguments properties, map, etc.
	 */

	duk_push_int(thr, num_stack_args);
	duk_xdef_prop_stridx(thr, i_arg, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_WC);

	/*
	 *  Init argument related properties.
	 */

	/* step 11 */
	idx = num_stack_args - 1;
	while (idx >= 0) {
		DUK_DDD(DUK_DDDPRINT("arg idx %ld, argbase=%ld, argidx=%ld",
		                     (long) idx, (long) i_argbase, (long) (i_argbase + idx)));

		DUK_DDD(DUK_DDDPRINT("define arguments[%ld]=arg", (long) idx));
		duk_dup(thr, i_argbase + idx);
		duk_xdef_prop_index_wec(thr, i_arg, (duk_uarridx_t) idx);
		DUK_DDD(DUK_DDDPRINT("defined arguments[%ld]=arg", (long) idx));

		/* step 11.c is relevant only if non-strict (checked in 11.c.ii) */
		if (!DUK_HOBJECT_HAS_STRICT(func) && idx < n_formals) {
			DUK_ASSERT(formals != NULL);

			DUK_DDD(DUK_DDDPRINT("strict function, index within formals (%ld < %ld)",
			                     (long) idx, (long) n_formals));

			duk_get_prop_index(thr, i_formals, (duk_uarridx_t) idx);
			DUK_ASSERT(duk_is_string(thr, -1));

			duk_dup_top(thr);  /* [ ... name name ] */

			if (!duk_has_prop(thr, i_mappednames)) {
				/* steps 11.c.ii.1 - 11.c.ii.4, but our internal book-keeping
				 * differs from the reference model
				 */

				/* [ ... name ] */

				need_map = 1;

				DUK_DDD(DUK_DDDPRINT("set mappednames[%s]=%ld",
				                     (const char *) duk_get_string(thr, -1),
				                     (long) idx));
				duk_dup_top(thr);                      /* name */
				(void) duk_push_uint_to_hstring(thr, (duk_uint_t) idx);  /* index */
				duk_xdef_prop_wec(thr, i_mappednames);  /* out of spec, must be configurable */

				DUK_DDD(DUK_DDDPRINT("set map[%ld]=%s",
				                     (long) idx,
				                     duk_get_string(thr, -1)));
				duk_dup_top(thr);         /* name */
				duk_xdef_prop_index_wec(thr, i_map, (duk_uarridx_t) idx);  /* out of spec, must be configurable */
			} else {
				/* duk_has_prop() popped the second 'name' */
			}

			/* [ ... name ] */
			duk_pop(thr);  /* pop 'name' */
		}

		idx--;
	}

	DUK_DDD(DUK_DDDPRINT("actual arguments processed"));

	/* step 12 */
	if (need_map) {
		DUK_DDD(DUK_DDDPRINT("adding 'map' and 'varenv' to arguments object"));

		/* should never happen for a strict callee */
		DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(func));

		duk_dup(thr, i_map);
		duk_xdef_prop_stridx(thr, i_arg, DUK_STRIDX_INT_MAP, DUK_PROPDESC_FLAGS_NONE);  /* out of spec, don't care */

		/* The variable environment for magic variable bindings needs to be
		 * given by the caller and recorded in the arguments object.
		 *
		 * See E5 Section 10.6, the creation of setters/getters.
		 *
		 * The variable environment also provides access to the callee, so
		 * an explicit (internal) callee property is not needed.
		 */

		duk_push_hobject(thr, varenv);
		duk_xdef_prop_stridx(thr, i_arg, DUK_STRIDX_INT_VARENV, DUK_PROPDESC_FLAGS_NONE);  /* out of spec, don't care */
	}

	/* steps 13-14 */
	if (DUK_HOBJECT_HAS_STRICT(func)) {
		/* Callee/caller are throwers and are not deletable etc.  They
		 * could be implemented as virtual properties, but currently
		 * there is no support for virtual properties which are accessors
		 * (only plain virtual properties).  This would not be difficult
		 * to change in duk_hobject_props, but we can make the throwers
		 * normal, concrete properties just as easily.
		 *
		 * Note that the specification requires that the *same* thrower
		 * built-in object is used here!  See E5 Section 10.6 main
		 * algoritm, step 14, and Section 13.2.3 which describes the
		 * thrower.  See test case test-arguments-throwers.js.
		 */

		DUK_DDD(DUK_DDDPRINT("strict function, setting caller/callee to throwers"));

		/* In ES2017 .caller is no longer set at all. */
		duk_xdef_prop_stridx_thrower(thr, i_arg, DUK_STRIDX_CALLEE);
	} else {
		DUK_DDD(DUK_DDDPRINT("non-strict function, setting callee to actual value"));
		duk_push_hobject(thr, func);
		duk_xdef_prop_stridx(thr, i_arg, DUK_STRIDX_CALLEE, DUK_PROPDESC_FLAGS_WC);
	}

	/* set exotic behavior only after we're done */
	if (need_map) {
		/* Exotic behaviors are only enabled for arguments objects
		 * which have a parameter map (see E5 Section 10.6 main
		 * algorithm, step 12).
		 *
		 * In particular, a non-strict arguments object with no
		 * mapped formals does *NOT* get exotic behavior, even
		 * for e.g. "caller" property.  This seems counterintuitive
		 * but seems to be the case.
		 */

		/* cannot be strict (never mapped variables) */
		DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(func));

		DUK_DDD(DUK_DDDPRINT("enabling exotic behavior for arguments object"));
		DUK_HOBJECT_SET_EXOTIC_ARGUMENTS(arg);
	} else {
		DUK_DDD(DUK_DDDPRINT("not enabling exotic behavior for arguments object"));
	}

	DUK_DDD(DUK_DDDPRINT("final arguments related objects: "
	                     "arguments at index %ld -> %!O "
	                     "map at index %ld -> %!O "
	                     "mappednames at index %ld -> %!O",
	                     (long) i_arg, (duk_heaphdr *) duk_get_hobject(thr, i_arg),
	                     (long) i_map, (duk_heaphdr *) duk_get_hobject(thr, i_map),
	                     (long) i_mappednames, (duk_heaphdr *) duk_get_hobject(thr, i_mappednames)));

	/* [ args(n) envobj formals arguments map mappednames ] */

	duk_pop_2(thr);
	duk_remove_m2(thr);

	/* [ args(n) envobj arguments ] */
}

/* Helper for creating the arguments object and adding it to the env record
 * on top of the value stack.
 */
DUK_LOCAL void duk__handle_createargs_for_call(duk_hthread *thr,
                                               duk_hobject *func,
                                               duk_hobject *env,
                                               duk_idx_t idx_args) {
	DUK_DDD(DUK_DDDPRINT("creating arguments object for function call"));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(env != NULL);
	DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));

	/* [ ... arg1 ... argN envobj ] */

	duk__create_arguments_object(thr,
	                             func,
	                             env,
	                             idx_args);

	/* [ ... arg1 ... argN envobj argobj ] */

	duk_xdef_prop_stridx_short(thr,
	                           -2,
	                           DUK_STRIDX_LC_ARGUMENTS,
	                           DUK_HOBJECT_HAS_STRICT(func) ? DUK_PROPDESC_FLAGS_E :   /* strict: non-deletable, non-writable */
	                                                          DUK_PROPDESC_FLAGS_WE);  /* non-strict: non-deletable, writable */
	/* [ ... arg1 ... argN envobj ] */
}

/*
 *  Helpers for constructor call handling.
 *
 *  There are two [[Construct]] operations in the specification:
 *
 *    - E5 Section 13.2.2: for Function objects
 *    - E5 Section 15.3.4.5.2: for "bound" Function objects
 *
 *  The chain of bound functions is resolved in Section 15.3.4.5.2,
 *  with arguments "piling up" until the [[Construct]] internal
 *  method is called on the final, actual Function object.  Note
 *  that the "prototype" property is looked up *only* from the
 *  final object, *before* calling the constructor.
 *
 *  Since Duktape 2.2 bound functions are represented with the
 *  duk_hboundfunc internal type, and bound function chains are
 *  collapsed when a bound function is created.  As a result, the
 *  direct target of a duk_hboundfunc is always non-bound and the
 *  this/argument lists have been resolved.
 *
 *  When constructing new Array instances, an unnecessary object is
 *  created and discarded now: the standard [[Construct]] creates an
 *  object, and calls the Array constructor.  The Array constructor
 *  returns an Array instance, which is used as the result value for
 *  the "new" operation; the object created before the Array constructor
 *  call is discarded.
 *
 *  This would be easy to fix, e.g. by knowing that the Array constructor
 *  will always create a replacement object and skip creating the fallback
 *  object in that case.
 */

/* Update default instance prototype for constructor call. */
DUK_LOCAL void duk__update_default_instance_proto(duk_hthread *thr, duk_idx_t idx_func) {
	duk_hobject *proto;
	duk_hobject *fallback;

	DUK_ASSERT(duk_is_constructable(thr, idx_func));

	duk_get_prop_stridx_short(thr, idx_func, DUK_STRIDX_PROTOTYPE);
	proto = duk_get_hobject(thr, -1);
	if (proto == NULL) {
		DUK_DDD(DUK_DDDPRINT("constructor has no 'prototype' property, or value not an object "
		                     "-> leave standard Object prototype as fallback prototype"));
	} else {
		DUK_DDD(DUK_DDDPRINT("constructor has 'prototype' property with object value "
		                     "-> set fallback prototype to that value: %!iO", (duk_heaphdr *) proto));
		/* Original fallback (default instance) is untouched when
		 * resolving bound functions etc.
		 */
		fallback = duk_known_hobject(thr, idx_func + 1);
		DUK_ASSERT(fallback != NULL);
		DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, fallback, proto);
	}
	duk_pop(thr);
}

/* Postprocess: return value special handling, error augmentation. */
DUK_INTERNAL void duk_call_construct_postprocess(duk_hthread *thr, duk_small_uint_t proxy_invariant) {
	/* Use either fallback (default instance) or retval depending
	 * on retval type.  Needs to be called before unwind because
	 * the default instance is read from the current (immutable)
	 * 'this' binding.
	 *
	 * For Proxy 'construct' calls the return value must be an
	 * Object (we accept object-like values like buffers and
	 * lightfuncs too).  If not, TypeError.
	 */
	if (duk_check_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT |
	                                 DUK_TYPE_MASK_BUFFER |
	                                 DUK_TYPE_MASK_LIGHTFUNC)) {
		DUK_DDD(DUK_DDDPRINT("replacement value"));
	} else {
		if (DUK_UNLIKELY(proxy_invariant != 0U)) {
			/* Proxy 'construct' return value invariant violated. */
			DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr);
			DUK_WO_NORETURN(return;);
		}
		/* XXX: direct value stack access */
		duk_pop(thr);
		duk_push_this(thr);
	}

#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
	/* Augment created errors upon creation, not when they are thrown or
	 * rethrown.  __FILE__ and __LINE__ are not desirable here; the call
	 * stack reflects the caller which is correct.  Skip topmost, unwound
	 * activation when creating a traceback.  If thr->ptr_curr_pc was !=
	 * NULL we'd need to sync the current PC so that the traceback comes
	 * out right; however it is always synced here so just assert for it.
	 */
	DUK_ASSERT(thr->ptr_curr_pc == NULL);
	duk_err_augment_error_create(thr, thr, NULL, 0, DUK_AUGMENT_FLAG_NOBLAME_FILELINE |
	                                                DUK_AUGMENT_FLAG_SKIP_ONE);
#endif
}

/*
 *  Helper for handling a bound function when a call is being made.
 *
 *  Assumes that bound function chains have been "collapsed" so that either
 *  the target is non-bound or there is one bound function that points to a
 *  nonbound target.
 *
 *  Prepends the bound arguments to the value stack (at idx_func + 2).
 *  The 'this' binding is also updated if necessary (at idx_func + 1).
 *  Note that for constructor calls the 'this' binding is never updated by
 *  [[BoundThis]].
 */

DUK_LOCAL void duk__handle_bound_chain_for_call(duk_hthread *thr,
                                                duk_idx_t idx_func,
                                                duk_bool_t is_constructor_call) {
	duk_tval *tv_func;
	duk_hobject *func;
	duk_idx_t len;

	DUK_ASSERT(thr != NULL);

	/* On entry, item at idx_func is a bound, non-lightweight function,
	 * but we don't rely on that below.
	 */

	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);

	tv_func = duk_require_tval(thr, idx_func);
	DUK_ASSERT(tv_func != NULL);

	if (DUK_TVAL_IS_OBJECT(tv_func)) {
		func = DUK_TVAL_GET_OBJECT(tv_func);

		/* XXX: separate helper function, out of fast path? */
		if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
			duk_hboundfunc *h_bound;
			duk_tval *tv_args;
			duk_tval *tv_gap;

			h_bound = (duk_hboundfunc *) (void *) func;
			tv_args = h_bound->args;
			len = h_bound->nargs;
			DUK_ASSERT(len == 0 || tv_args != NULL);

			DUK_DDD(DUK_DDDPRINT("bound function encountered, ptr=%p: %!T",
			                     (void *) DUK_TVAL_GET_OBJECT(tv_func), tv_func));

			/* [ ... func this arg1 ... argN ] */

			if (is_constructor_call) {
				/* See: tests/ecmascript/test-spec-bound-constructor.js */
				DUK_DDD(DUK_DDDPRINT("constructor call: don't update this binding"));
			} else {
				/* XXX: duk_replace_tval */
				duk_push_tval(thr, &h_bound->this_binding);
				duk_replace(thr, idx_func + 1);  /* idx_this = idx_func + 1 */
			}

			/* [ ... func this arg1 ... argN ] */

			duk_require_stack(thr, len);

			tv_gap = duk_reserve_gap(thr, idx_func + 2, len);
			duk_copy_tvals_incref(thr, tv_gap, tv_args, (duk_size_t) len);

			/* [ ... func this <bound args> arg1 ... argN ] */

			duk_push_tval(thr, &h_bound->target);
			duk_replace(thr, idx_func);  /* replace in stack */

			DUK_DDD(DUK_DDDPRINT("bound function handled, idx_func=%ld, curr func=%!T",
			                     (long) idx_func, duk_get_tval(thr, idx_func)));
		}
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
		/* Lightweight function: never bound, so terminate. */
		;
	} else {
		/* Shouldn't happen, so ugly error is enough. */
		DUK_ERROR_INTERNAL(thr);
		DUK_WO_NORETURN(return;);
	}

	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);

	DUK_DDD(DUK_DDDPRINT("final non-bound function is: %!T", duk_get_tval(thr, idx_func)));

#if defined(DUK_USE_ASSERTIONS)
	tv_func = duk_require_tval(thr, idx_func);
	DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func) || DUK_TVAL_IS_OBJECT(tv_func));
	if (DUK_TVAL_IS_OBJECT(tv_func)) {
		func = DUK_TVAL_GET_OBJECT(tv_func);
		DUK_ASSERT(func != NULL);
		DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
		DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func) ||
		           DUK_HOBJECT_HAS_NATFUNC(func) ||
		           DUK_HOBJECT_IS_PROXY(func));
	}
#endif
}

/*
 *  Helper for inline handling of .call(), .apply(), and .construct().
 */

DUK_LOCAL duk_bool_t duk__handle_specialfuncs_for_call(duk_hthread *thr, duk_idx_t idx_func, duk_hobject *func, duk_small_uint_t *call_flags, duk_bool_t first) {
#if defined(DUK_USE_ASSERTIONS)
	duk_c_function natfunc;
#endif
	duk_tval *tv_args;

	DUK_ASSERT(func != NULL);
	DUK_ASSERT((*call_flags & DUK_CALL_FLAG_CONSTRUCT) == 0);  /* Caller. */

#if defined(DUK_USE_ASSERTIONS)
	natfunc = ((duk_hnatfunc *) func)->func;
	DUK_ASSERT(natfunc != NULL);
#endif

	/* On every round of function resolution at least target function and
	 * 'this' binding are set.  We can assume that here, and must guarantee
	 * it on exit.  Value stack reserve is extended for bound function and
	 * .apply() unpacking so we don't need to extend it here when we need a
	 * few slots.
	 */
	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);

	/* Handle native 'eval' specially.  A direct eval check is only made
	 * for the first resolution attempt; e.g. a bound eval call is -not-
	 * a direct eval call.
	 */
	if (DUK_UNLIKELY(((duk_hnatfunc *) func)->magic == 15)) {
		/* For now no special handling except for direct eval
		 * detection.
		 */
		DUK_ASSERT(((duk_hnatfunc *) func)->func == duk_bi_global_object_eval);
		if (first && (*call_flags & DUK_CALL_FLAG_CALLED_AS_EVAL)) {
			*call_flags = (*call_flags & ~DUK_CALL_FLAG_CALLED_AS_EVAL) | DUK_CALL_FLAG_DIRECT_EVAL;
		}
		DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
		return 1;  /* stop resolving */
	}

	/* Handle special functions based on the DUK_HOBJECT_FLAG_SPECIAL_CALL
	 * flag; their magic value is used for switch-case.
	 *
	 * NOTE: duk_unpack_array_like() reserves value stack space
	 * for the result values (unlike most other value stack calls).
	 */
	switch (((duk_hnatfunc *) func)->magic) {
	case 0: {  /* 0=Function.prototype.call() */
		/* Value stack:
		 * idx_func + 0: Function.prototype.call()  [removed]
		 * idx_func + 1: this binding for .call (target function)
		 * idx_func + 2: 1st argument to .call, desired 'this' binding
		 * idx_func + 3: 2nd argument to .call, desired 1st argument for ultimate target
		 * ...
		 *
		 * Remove idx_func + 0 to get:
		 * idx_func + 0: target function
		 * idx_func + 1: this binding
		 * idx_func + 2: call arguments
		 * ...
		 */
		DUK_ASSERT(natfunc == duk_bi_function_prototype_call);
		duk_remove_unsafe(thr, idx_func);
		tv_args = thr->valstack_bottom + idx_func + 2;
		if (thr->valstack_top < tv_args) {
			DUK_ASSERT(tv_args <= thr->valstack_end);
			thr->valstack_top = tv_args;  /* at least target function and 'this' binding present */
		}
		break;
	}
	case 1: {  /* 1=Function.prototype.apply() */
		/* Value stack:
		 * idx_func + 0: Function.prototype.apply()  [removed]
		 * idx_func + 1: this binding for .apply (target function)
		 * idx_func + 2: 1st argument to .apply, desired 'this' binding
		 * idx_func + 3: 2nd argument to .apply, argArray
		 * [anything after this MUST be ignored]
		 *
		 * Remove idx_func + 0 and unpack the argArray to get:
		 * idx_func + 0: target function
		 * idx_func + 1: this binding
		 * idx_func + 2: call arguments
		 * ...
		 */
		DUK_ASSERT(natfunc == duk_bi_function_prototype_apply);
		duk_remove_unsafe(thr, idx_func);
		goto apply_shared;
	}
#if defined(DUK_USE_REFLECT_BUILTIN)
	case 2: {  /* 2=Reflect.apply() */
		/* Value stack:
		 * idx_func + 0: Reflect.apply()  [removed]
		 * idx_func + 1: this binding for .apply (ignored, usually Reflect)  [removed]
		 * idx_func + 2: 1st argument to .apply, target function
		 * idx_func + 3: 2nd argument to .apply, desired 'this' binding
		 * idx_func + 4: 3rd argument to .apply, argArray
		 * [anything after this MUST be ignored]
		 *
		 * Remove idx_func + 0 and idx_func + 1, and unpack the argArray to get:
		 * idx_func + 0: target function
		 * idx_func + 1: this binding
		 * idx_func + 2: call arguments
		 * ...
		 */
		DUK_ASSERT(natfunc == duk_bi_reflect_apply);
		duk_remove_n_unsafe(thr, idx_func, 2);
		goto apply_shared;
	}
	case 3: {  /* 3=Reflect.construct() */
		/* Value stack:
		 * idx_func + 0: Reflect.construct()  [removed]
		 * idx_func + 1: this binding for .construct (ignored, usually Reflect)  [removed]
		 * idx_func + 2: 1st argument to .construct, target function
		 * idx_func + 3: 2nd argument to .construct, argArray
		 * idx_func + 4: 3rd argument to .construct, newTarget
		 * [anything after this MUST be ignored]
		 *
		 * Remove idx_func + 0 and idx_func + 1, unpack the argArray,
		 * and insert default instance (prototype not yet updated), to get:
		 * idx_func + 0: target function
		 * idx_func + 1: this binding (default instance)
		 * idx_func + 2: constructor call arguments
		 * ...
		 *
		 * Call flags must be updated to reflect the fact that we're
		 * now dealing with a constructor call, and e.g. the 'this'
		 * binding cannot be overwritten if the target is bound.
		 *
		 * newTarget is checked but not yet passed onwards.
		 */

		duk_idx_t top;

		DUK_ASSERT(natfunc == duk_bi_reflect_construct);
		*call_flags |= DUK_CALL_FLAG_CONSTRUCT;
		duk_remove_n_unsafe(thr, idx_func, 2);
		top = duk_get_top(thr);
		if (!duk_is_constructable(thr, idx_func)) {
			/* Target constructability must be checked before
			 * unpacking argArray (which may cause side effects).
			 * Just return; caller will throw the error.
			 */
			duk_set_top_unsafe(thr, idx_func + 2);  /* satisfy asserts */
			break;
		}
		duk_push_object(thr);
		duk_insert(thr, idx_func + 1);  /* default instance */

		/* [ ... func default_instance argArray newTarget? ] */

		top = duk_get_top(thr);
		if (top < idx_func + 3) {
			/* argArray is a mandatory argument for Reflect.construct(). */
			DUK_ERROR_TYPE_INVALID_ARGS(thr);
			DUK_WO_NORETURN(return 0;);
		}
		if (top > idx_func + 3) {
			if (!duk_strict_equals(thr, idx_func, idx_func + 3)) {
				/* XXX: [[Construct]] newTarget currently unsupported */
				DUK_ERROR_UNSUPPORTED(thr);
				DUK_WO_NORETURN(return 0;);
			}
			duk_set_top_unsafe(thr, idx_func + 3);  /* remove any args beyond argArray */
		}
		DUK_ASSERT(duk_get_top(thr) == idx_func + 3);
		DUK_ASSERT(duk_is_valid_index(thr, idx_func + 2));
		(void) duk_unpack_array_like(thr, idx_func + 2);  /* XXX: should also remove target to be symmetric with duk_pack()? */
		duk_remove(thr, idx_func + 2);
		DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
		break;
	}
#endif  /* DUK_USE_REFLECT_BUILTIN */
	default: {
		DUK_ASSERT(0);
		DUK_UNREACHABLE();
	}
	}

	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
	return 0;  /* keep resolving */

 apply_shared:
	tv_args = thr->valstack_bottom + idx_func + 2;
	if (thr->valstack_top <= tv_args) {
		DUK_ASSERT(tv_args <= thr->valstack_end);
		thr->valstack_top = tv_args;  /* at least target func and 'this' binding present */
		/* No need to check for argArray. */
	} else {
		DUK_ASSERT(duk_get_top(thr) >= idx_func + 3);  /* idx_func + 2 covered above */
		if (thr->valstack_top > tv_args + 1) {
			duk_set_top_unsafe(thr, idx_func + 3);  /* remove any args beyond argArray */
		}
		DUK_ASSERT(duk_is_valid_index(thr, idx_func + 2));
		if (!duk_is_callable(thr, idx_func)) {
			/* Avoid unpack side effects if the target isn't callable.
			 * Calling code will throw the actual error.
			 */
		} else {
			(void) duk_unpack_array_like(thr, idx_func + 2);
			duk_remove(thr, idx_func + 2);
		}
	}
	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
	return 0;  /* keep resolving */
}

/*
 *  Helper for Proxy handling.
 */

#if defined(DUK_USE_ES6_PROXY)
DUK_LOCAL void duk__handle_proxy_for_call(duk_hthread *thr, duk_idx_t idx_func, duk_hproxy *h_proxy, duk_small_uint_t *call_flags) {
	duk_bool_t rc;

	/* Value stack:
	 * idx_func + 0: Proxy object
	 * idx_func + 1: this binding for call
	 * idx_func + 2: 1st argument for call
	 * idx_func + 3: 2nd argument for call
	 * ...
	 *
	 * If Proxy doesn't have a trap for the call ('apply' or 'construct'),
	 * replace Proxy object with target object.
	 *
	 * If we're dealing with a normal call and the Proxy has an 'apply'
	 * trap, manipulate value stack to:
	 *
	 * idx_func + 0: trap
	 * idx_func + 1: Proxy's handler
	 * idx_func + 2: Proxy's target
	 * idx_func + 3: this binding for call (from idx_func + 1)
	 * idx_func + 4: call arguments packed to an array
	 *
	 * If we're dealing with a constructor call and the Proxy has a
	 * 'construct' trap, manipulate value stack to:
	 *
	 * idx_func + 0: trap
	 * idx_func + 1: Proxy's handler
	 * idx_func + 2: Proxy's target
	 * idx_func + 3: call arguments packed to an array
	 * idx_func + 4: newTarget == Proxy object here
	 *
	 * As we don't yet have proper newTarget support, the newTarget at
	 * idx_func + 3 is just the original constructor being called, i.e.
	 * the Proxy object (not the target).  Note that the default instance
	 * (original 'this' binding) is dropped and ignored.
	 */

	duk_push_hobject(thr, h_proxy->handler);
	rc = duk_get_prop_stridx_short(thr, -1, (*call_flags & DUK_CALL_FLAG_CONSTRUCT) ? DUK_STRIDX_CONSTRUCT : DUK_STRIDX_APPLY);
	if (rc == 0) {
		/* Not found, continue to target.  If this is a construct
		 * call, update default instance prototype using the Proxy,
		 * not the target.
		 */
		if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
			if (!(*call_flags & DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED)) {
				*call_flags |= DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED;
				duk__update_default_instance_proto(thr, idx_func);
			}
		}
		duk_pop_2(thr);
		duk_push_hobject(thr, h_proxy->target);
		duk_replace(thr, idx_func);
		return;
	}

	/* Here we must be careful not to replace idx_func while
	 * h_proxy is still needed, otherwise h_proxy may become
	 * dangling.  This could be improved e.g. using a
	 * duk_pack_slice() with a freeform slice.
	 */

	/* Here:
	 * idx_func + 0: Proxy object
	 * idx_func + 1: this binding for call
	 * idx_func + 2: 1st argument for call
	 * idx_func + 3: 2nd argument for call
	 * ...
	 * idx_func + N: handler
	 * idx_func + N + 1: trap
	 */

	duk_insert(thr, idx_func + 1);
	duk_insert(thr, idx_func + 2);
	duk_push_hobject(thr, h_proxy->target);
	duk_insert(thr, idx_func + 3);
	duk_pack(thr, duk_get_top(thr) - (idx_func + 5));
	DUK_ASSERT(!duk_is_bare_object(thr, -1));

	/* Here:
	 * idx_func + 0: Proxy object
	 * idx_func + 1: trap
	 * idx_func + 2: Proxy's handler
	 * idx_func + 3: Proxy's target
	 * idx_func + 4: this binding for call
	 * idx_func + 5: arguments array
	 */
	DUK_ASSERT(duk_get_top(thr) == idx_func + 6);

	if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
		*call_flags |= DUK_CALL_FLAG_CONSTRUCT_PROXY;  /* Enable 'construct' trap return invariant check. */
		*call_flags &= ~(DUK_CALL_FLAG_CONSTRUCT);     /* Resume as non-constructor call to the trap. */

		/* 'apply' args: target, thisArg, argArray
		 * 'construct' args: target, argArray, newTarget
		 */
		duk_remove(thr, idx_func + 4);
		duk_push_hobject(thr, (duk_hobject *) h_proxy);
	}

	/* Finalize value stack layout by removing Proxy reference. */
	duk_remove(thr, idx_func);
	h_proxy = NULL;  /* invalidated */
	DUK_ASSERT(duk_get_top(thr) == idx_func + 5);
}
#endif  /* DUK_USE_ES6_PROXY */

/*
 *  Helper for setting up var_env and lex_env of an activation,
 *  assuming it does NOT have the DUK_HOBJECT_FLAG_NEWENV flag.
 */

DUK_LOCAL void duk__handle_oldenv_for_call(duk_hthread *thr,
                                           duk_hobject *func,
                                           duk_activation *act) {
	duk_hcompfunc *f;
	duk_hobject *h_lex;
	duk_hobject *h_var;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(!DUK_HOBJECT_HAS_NEWENV(func));
	DUK_ASSERT(!DUK_HOBJECT_HAS_CREATEARGS(func));
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(func));
	DUK_UNREF(thr);

	f = (duk_hcompfunc *) func;
	h_lex = DUK_HCOMPFUNC_GET_LEXENV(thr->heap, f);
	h_var = DUK_HCOMPFUNC_GET_VARENV(thr->heap, f);
	DUK_ASSERT(h_lex != NULL);  /* Always true for closures (not for templates) */
	DUK_ASSERT(h_var != NULL);
	act->lex_env = h_lex;
	act->var_env = h_var;
	DUK_HOBJECT_INCREF(thr, h_lex);
	DUK_HOBJECT_INCREF(thr, h_var);
}

/*
 *  Helper for updating callee 'caller' property.
 */

#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
DUK_LOCAL void duk__update_func_caller_prop(duk_hthread *thr, duk_hobject *func) {
	duk_tval *tv_caller;
	duk_hobject *h_tmp;
	duk_activation *act_callee;
	duk_activation *act_caller;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));  /* bound chain resolved */
	DUK_ASSERT(thr->callstack_top >= 1);

	if (DUK_HOBJECT_HAS_STRICT(func)) {
		/* Strict functions don't get their 'caller' updated. */
		return;
	}

	DUK_ASSERT(thr->callstack_top > 0);
	act_callee = thr->callstack_curr;
	DUK_ASSERT(act_callee != NULL);
	act_caller = (thr->callstack_top >= 2 ? act_callee->parent : NULL);

	/* XXX: check .caller writability? */

	/* Backup 'caller' property and update its value. */
	tv_caller = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, func, DUK_STRIDX_CALLER);
	if (tv_caller) {
		/* If caller is global/eval code, 'caller' should be set to
		 * 'null'.
		 *
		 * XXX: there is no exotic flag to infer this correctly now.
		 * The NEWENV flag is used now which works as intended for
		 * everything (global code, non-strict eval code, and functions)
		 * except strict eval code.  Bound functions are never an issue
		 * because 'func' has been resolved to a non-bound function.
		 */

		if (act_caller != NULL) {
			/* act_caller->func may be NULL in some finalization cases,
			 * just treat like we don't know the caller.
			 */
			if (act_caller->func && !DUK_HOBJECT_HAS_NEWENV(act_caller->func)) {
				/* Setting to NULL causes 'caller' to be set to
				 * 'null' as desired.
				 */
				act_caller = NULL;
			}
		}

		if (DUK_TVAL_IS_OBJECT(tv_caller)) {
			h_tmp = DUK_TVAL_GET_OBJECT(tv_caller);
			DUK_ASSERT(h_tmp != NULL);
			act_callee->prev_caller = h_tmp;

			/* Previous value doesn't need refcount changes because its ownership
			 * is transferred to prev_caller.
			 */

			if (act_caller != NULL) {
				DUK_ASSERT(act_caller->func != NULL);
				DUK_TVAL_SET_OBJECT(tv_caller, act_caller->func);
				DUK_TVAL_INCREF(thr, tv_caller);
			} else {
				DUK_TVAL_SET_NULL(tv_caller);  /* no incref */
			}
		} else {
			/* 'caller' must only take on 'null' or function value */
			DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_caller));
			DUK_ASSERT(act_callee->prev_caller == NULL);
			if (act_caller != NULL && act_caller->func) {
				/* Tolerate act_caller->func == NULL which happens in
				 * some finalization cases; treat like unknown caller.
				 */
				DUK_TVAL_SET_OBJECT(tv_caller, act_caller->func);
				DUK_TVAL_INCREF(thr, tv_caller);
			} else {
				DUK_TVAL_SET_NULL(tv_caller);  /* no incref */
			}
		}
	}
}
#endif  /* DUK_USE_NONSTD_FUNC_CALLER_PROPERTY */

/*
 *  Shared helpers for resolving the final, non-bound target function of the
 *  call and the effective 'this' binding.  Resolves bound functions and
 *  applies .call(), .apply(), and .construct() inline.
 *
 *  Proxy traps are also handled inline so that if the target is a Proxy with
 *  a 'call' or 'construct' trap, the trap handler is called with a modified
 *  argument list.
 *
 *  Once the bound function / .call() / .apply() / .construct() sequence has
 *  been resolved, the value at idx_func + 1 may need coercion described in
 *  E5 Section 10.4.3.
 *
 *  A call that begins as a non-constructor call may be converted into a
 *  constructor call during the resolution process if Reflect.construct()
 *  is invoked.  This is handled by updating the caller's call_flags.
 *
 *  For global and eval code (E5 Sections 10.4.1 and 10.4.2), we assume
 *  that the caller has provided the correct 'this' binding explicitly
 *  when calling, i.e.:
 *
 *    - global code: this=global object
 *    - direct eval: this=copy from eval() caller's this binding
 *    - other eval:  this=global object
 *
 *  The 'this' coercion may cause a recursive function call with arbitrary
 *  side effects, because ToObject() may be called.
 */

DUK_LOCAL DUK_INLINE void duk__coerce_nonstrict_this_binding(duk_hthread *thr, duk_idx_t idx_this) {
	duk_tval *tv_this;
	duk_hobject *obj_global;

	tv_this = thr->valstack_bottom + idx_this;
	switch (DUK_TVAL_GET_TAG(tv_this)) {
	case DUK_TAG_OBJECT:
		DUK_DDD(DUK_DDDPRINT("this binding: non-strict, object -> use directly"));
		break;
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL:
		DUK_DDD(DUK_DDDPRINT("this binding: non-strict, undefined/null -> use global object"));
		obj_global = thr->builtins[DUK_BIDX_GLOBAL];
		/* XXX: avoid this check somehow */
		if (DUK_LIKELY(obj_global != NULL)) {
			DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_this));  /* no need to decref previous value */
			DUK_TVAL_SET_OBJECT(tv_this, obj_global);
			DUK_HOBJECT_INCREF(thr, obj_global);
		} else {
			/* This may only happen if built-ins are being "torn down".
			 * This behavior is out of specification scope.
			 */
			DUK_D(DUK_DPRINT("this binding: wanted to use global object, but it is NULL -> using undefined instead"));
			DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_this));  /* no need to decref previous value */
			DUK_TVAL_SET_UNDEFINED(tv_this);  /* nothing to incref */
		}
		break;
	default:
		/* Plain buffers and lightfuncs are object coerced.  Lightfuncs
		 * very rarely come here however, because the call target would
		 * need to be a non-strict non-lightfunc (lightfuncs are considered
		 * strict) with an explicit lightfunc 'this' binding.
		 */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_this));
		DUK_DDD(DUK_DDDPRINT("this binding: non-strict, not object/undefined/null -> use ToObject(value)"));
		duk_to_object(thr, idx_this);  /* may have side effects */
		break;
	}
}

DUK_LOCAL DUK_ALWAYS_INLINE duk_bool_t duk__resolve_target_fastpath_check(duk_hthread *thr, duk_idx_t idx_func, duk_hobject **out_func, duk_small_uint_t call_flags) {
#if defined(DUK_USE_PREFER_SIZE)
	DUK_UNREF(thr);
	DUK_UNREF(idx_func);
	DUK_UNREF(out_func);
	DUK_UNREF(call_flags);
#else  /* DUK_USE_PREFER_SIZE */
	duk_tval *tv_func;
	duk_hobject *func;

	if (DUK_UNLIKELY(call_flags & DUK_CALL_FLAG_CONSTRUCT)) {
		return 0;
	}

	tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
	DUK_ASSERT(tv_func != NULL);

	if (DUK_LIKELY(DUK_TVAL_IS_OBJECT(tv_func))) {
		func = DUK_TVAL_GET_OBJECT(tv_func);
		if (DUK_HOBJECT_IS_CALLABLE(func) &&
		    !DUK_HOBJECT_HAS_BOUNDFUNC(func) &&
		    !DUK_HOBJECT_HAS_SPECIAL_CALL(func)) {
			*out_func = func;

			if (DUK_HOBJECT_HAS_STRICT(func)) {
				/* Strict function: no 'this' coercion. */
				return 1;
			}

			duk__coerce_nonstrict_this_binding(thr, idx_func + 1);
			return 1;
		}
	} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
		*out_func = NULL;

		/* Lightfuncs are considered strict, so 'this' binding is
		 * used as is.  They're never bound, always constructable,
		 * and never special functions.
		 */
		return 1;
	}
#endif  /* DUK_USE_PREFER_SIZE */
	return 0;  /* let slow path deal with it */
}

DUK_LOCAL duk_hobject *duk__resolve_target_func_and_this_binding(duk_hthread *thr,
                                                                 duk_idx_t idx_func,
                                                                 duk_small_uint_t *call_flags) {
	duk_tval *tv_func;
	duk_hobject *func;
	duk_bool_t first;

	DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);

	for (first = 1;; first = 0) {
		DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);

		tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
		DUK_ASSERT(tv_func != NULL);

		DUK_DD(DUK_DDPRINT("target func: %!iT", tv_func));

		if (DUK_TVAL_IS_OBJECT(tv_func)) {
			func = DUK_TVAL_GET_OBJECT(tv_func);

			if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
				if (DUK_UNLIKELY(!DUK_HOBJECT_HAS_CONSTRUCTABLE(func))) {
					goto not_constructable;
				}
			} else {
				if (DUK_UNLIKELY(!DUK_HOBJECT_IS_CALLABLE(func))) {
					goto not_callable;
				}
			}

			if (DUK_LIKELY(!DUK_HOBJECT_HAS_BOUNDFUNC(func) &&
			               !DUK_HOBJECT_HAS_SPECIAL_CALL(func) &&
			               !DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(func))) {
				/* Common case, so test for using a single bitfield test.
				 * Break out to handle this coercion etc.
				 */
				break;
			}

			/* XXX: could set specialcall for boundfuncs too, simplify check above */

			if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
				DUK_ASSERT(!DUK_HOBJECT_HAS_SPECIAL_CALL(func));
				DUK_ASSERT(!DUK_HOBJECT_IS_NATFUNC(func));

				/* Callable/constructable flags are the same
				 * for the bound function and its target, so
				 * we don't need to check them here, we can
				 * check them from the target only.
				 */
				duk__handle_bound_chain_for_call(thr, idx_func, *call_flags & DUK_CALL_FLAG_CONSTRUCT);

				DUK_ASSERT(DUK_TVAL_IS_OBJECT(duk_require_tval(thr, idx_func)) ||
				           DUK_TVAL_IS_LIGHTFUNC(duk_require_tval(thr, idx_func)));
			} else {
				DUK_ASSERT(DUK_HOBJECT_HAS_SPECIAL_CALL(func));

#if defined(DUK_USE_ES6_PROXY)
				if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(func)) {
					/* If no trap, resume processing from Proxy trap.
					 * If trap exists, helper converts call into a trap
					 * call; this may change a constructor call into a
					 * normal (non-constructor) trap call.  We must
					 * continue processing even when a trap is found as
					 * the trap may be bound.
					 */
					duk__handle_proxy_for_call(thr, idx_func, (duk_hproxy *) func, call_flags);
				}
				else
#endif
				{
					DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(func));
					DUK_ASSERT(DUK_HOBJECT_HAS_CALLABLE(func));
					DUK_ASSERT(!DUK_HOBJECT_HAS_CONSTRUCTABLE(func));
					/* Constructable check already done above. */

					if (duk__handle_specialfuncs_for_call(thr, idx_func, func, call_flags, first) != 0) {
						/* Encountered native eval call, normal call
						 * context.  Break out, handle this coercion etc.
						 */
						break;
					}
				}
			}
			/* Retry loop. */
		} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
			/* Lightfuncs are:
			 *   - Always strict, so no 'this' coercion.
			 *   - Always callable.
			 *   - Always constructable.
			 *   - Never specialfuncs.
			 */
			func = NULL;
			goto finished;
		} else {
			goto not_callable;
		}
	}

	DUK_ASSERT(func != NULL);

	if (!DUK_HOBJECT_HAS_STRICT(func)) {
		/* Non-strict target needs 'this' coercion.
		 * This has potential side effects invalidating
		 * 'tv_func'.
		 */
		duk__coerce_nonstrict_this_binding(thr, idx_func + 1);
	}
	if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
		if (!(*call_flags & DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED)) {
			*call_flags |= DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED;
			duk__update_default_instance_proto(thr, idx_func);
		}
	}

 finished:

#if defined(DUK_USE_ASSERTIONS)
	{
		duk_tval *tv_tmp;

		tv_tmp = duk_get_tval(thr, idx_func);
		DUK_ASSERT(tv_tmp != NULL);

		DUK_ASSERT((DUK_TVAL_IS_OBJECT(tv_tmp) && DUK_HOBJECT_IS_CALLABLE(DUK_TVAL_GET_OBJECT(tv_tmp))) ||
		           DUK_TVAL_IS_LIGHTFUNC(tv_tmp));
		DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
		DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
		                            DUK_HOBJECT_IS_NATFUNC(func)));
		DUK_ASSERT(func == NULL || (DUK_HOBJECT_HAS_CONSTRUCTABLE(func) ||
		                            (*call_flags & DUK_CALL_FLAG_CONSTRUCT) == 0));
	}
#endif

	return func;

 not_callable:
	DUK_ASSERT(tv_func != NULL);

#if defined(DUK_USE_VERBOSE_ERRORS)
	/* GETPROPC delayed error handling: when target is not callable,
	 * GETPROPC replaces idx_func+0 with a non-callable wrapper object
	 * with a hidden Symbol to signify it's to be handled here.  If
	 * found, unwrap the original Error and throw it as is here.  The
	 * hidden Symbol is only checked as an own property, not inherited
	 * (which would be dangerous).
	 */
	if (DUK_TVAL_IS_OBJECT(tv_func)) {
		duk_tval *tv_wrap = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, DUK_TVAL_GET_OBJECT(tv_func), DUK_STRIDX_INT_TARGET);
		if (tv_wrap != NULL) {
			DUK_DD(DUK_DDPRINT("delayed error from GETPROPC: %!T", tv_wrap));
			duk_push_tval(thr, tv_wrap);
			(void) duk_throw(thr);
			DUK_WO_NORETURN(return NULL;);
		}
	}
#endif

#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
	DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not callable", duk_get_type_name(thr, idx_func));
#else
	DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not callable", duk_push_string_tval_readable(thr, tv_func));
#endif
#else
	DUK_ERROR_TYPE(thr, DUK_STR_NOT_CALLABLE);
#endif
	DUK_WO_NORETURN(return NULL;);

 not_constructable:
	/* For now GETPROPC delayed error not needed for constructor calls. */
#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
	DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_get_type_name(thr, idx_func));
#else
	DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_push_string_tval_readable(thr, tv_func));
#endif
#else
	DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONSTRUCTABLE);
#endif
	DUK_WO_NORETURN(return NULL;);
}

/*
 *  Manipulate value stack so that exactly 'num_stack_rets' return
 *  values are at 'idx_retbase' in every case, assuming there are
 *  'rc' return values on top of stack.
 *
 *  This is a bit tricky, because the called C function operates in
 *  the same activation record and may have e.g. popped the stack
 *  empty (below idx_retbase).
 */

DUK_LOCAL void duk__safe_call_adjust_valstack(duk_hthread *thr, duk_idx_t idx_retbase, duk_idx_t num_stack_rets, duk_idx_t num_actual_rets) {
	duk_idx_t idx_rcbase;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(idx_retbase >= 0);
	DUK_ASSERT(num_stack_rets >= 0);
	DUK_ASSERT(num_actual_rets >= 0);

	idx_rcbase = duk_get_top(thr) - num_actual_rets;  /* base of known return values */
	if (DUK_UNLIKELY(idx_rcbase < 0)) {
		DUK_ERROR_TYPE(thr, DUK_STR_INVALID_CFUNC_RC);
		DUK_WO_NORETURN(return;);
	}

	DUK_DDD(DUK_DDDPRINT("adjust valstack after func call: "
	                     "num_stack_rets=%ld, num_actual_rets=%ld, stack_top=%ld, idx_retbase=%ld, idx_rcbase=%ld",
	                     (long) num_stack_rets, (long) num_actual_rets, (long) duk_get_top(thr),
	                     (long) idx_retbase, (long) idx_rcbase));

	DUK_ASSERT(idx_rcbase >= 0);  /* caller must check */

	/* Space for num_stack_rets was reserved before the safe call.
	 * Because value stack reserve cannot shrink except in call returns,
	 * the reserve is still in place.  Adjust valstack, carefully
	 * ensuring we don't overstep the reserve.
	 */

	/* Match idx_rcbase with idx_retbase so that the return values
	 * start at the correct index.
	 */
	if (idx_rcbase > idx_retbase) {
		duk_idx_t count = idx_rcbase - idx_retbase;

		DUK_DDD(DUK_DDDPRINT("elements at/after idx_retbase have enough to cover func retvals "
		                     "(idx_retbase=%ld, idx_rcbase=%ld)", (long) idx_retbase, (long) idx_rcbase));

		/* Remove values between irc_rcbase (start of intended return
		 * values) and idx_retbase to lower return values to idx_retbase.
		 */
		DUK_ASSERT(count > 0);
		duk_remove_n(thr, idx_retbase, count);  /* may be NORZ */
	} else {
		duk_idx_t count = idx_retbase - idx_rcbase;

		DUK_DDD(DUK_DDDPRINT("not enough elements at/after idx_retbase to cover func retvals "
		                     "(idx_retbase=%ld, idx_rcbase=%ld)", (long) idx_retbase, (long) idx_rcbase));

		/* Insert 'undefined' at idx_rcbase (start of intended return
		 * values) to lift return values to idx_retbase.
		 */
		DUK_ASSERT(count >= 0);
		DUK_ASSERT(thr->valstack_end - thr->valstack_top >= count);  /* reserve cannot shrink */
		duk_insert_undefined_n(thr, idx_rcbase, count);
	}

	/* Chop extra retvals away / extend with undefined. */
	duk_set_top_unsafe(thr, idx_retbase + num_stack_rets);
}

/*
 *  Activation setup for tailcalls and non-tailcalls.
 */

#if defined(DUK_USE_TAILCALL)
DUK_LOCAL duk_small_uint_t duk__call_setup_act_attempt_tailcall(duk_hthread *thr,
                                                                duk_small_uint_t call_flags,
                                                                duk_idx_t idx_func,
                                                                duk_hobject *func,
                                                                duk_size_t entry_valstack_bottom_byteoff,
                                                                duk_size_t entry_valstack_end_byteoff,
                                                                duk_idx_t *out_nargs,
                                                                duk_idx_t *out_nregs,
                                                                duk_size_t *out_vs_min_bytes,
                                                                duk_activation **out_act) {
	duk_activation *act;
	duk_tval *tv1, *tv2;
	duk_idx_t idx_args;
	duk_small_uint_t flags1, flags2;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_activation *prev_pause_act;
#endif

	DUK_UNREF(entry_valstack_end_byteoff);

	/* Tailcall cannot be flagged to resume calls, and a
	 * previous frame must exist.
	 */
	DUK_ASSERT(thr->callstack_top >= 1);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	*out_act = act;

	if (func == NULL || !DUK_HOBJECT_IS_COMPFUNC(func)) {
		DUK_DDD(DUK_DDDPRINT("tail call prevented by target not being ecma function"));
		return 0;
	}
	if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
		DUK_DDD(DUK_DDDPRINT("tail call prevented by current activation having DUK_ACT_FLAG_PREVENT_YIELD"));
		return 0;
	}
	/* Tailcall is only allowed if current and candidate
	 * function have identical return value handling.  There
	 * are three possible return value handling cases:
	 *   1. Normal function call, no special return value handling.
	 *   2. Constructor call, return value replacement object check.
	 *   3. Proxy 'construct' trap call, return value invariant check.
	 */
	flags1 = (duk_small_uint_t) ((act->flags & DUK_ACT_FLAG_CONSTRUCT) ? 1 : 0)
#if defined(DUK_USE_ES6_PROXY)
	         | (duk_small_uint_t) ((act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) ? 2 : 0)
#endif
	         ;
	flags2 = (duk_small_uint_t) ((call_flags & DUK_CALL_FLAG_CONSTRUCT) ? 1 : 0)
#if defined(DUK_USE_ES6_PROXY)
	         | (duk_small_uint_t) ((call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) ? 2 : 0);
#endif
	         ;
	if (flags1 != flags2) {
		DUK_DDD(DUK_DDDPRINT("tail call prevented by incompatible return value handling"));
		return 0;
	}
	DUK_ASSERT(((act->flags & DUK_ACT_FLAG_CONSTRUCT) && (call_flags & DUK_CALL_FLAG_CONSTRUCT)) ||
	           (!(act->flags & DUK_ACT_FLAG_CONSTRUCT) && !(call_flags & DUK_CALL_FLAG_CONSTRUCT)));
	DUK_ASSERT(((act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) && (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY)) ||
	           (!(act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) && !(call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY)));
	if (DUK_HOBJECT_HAS_NOTAIL(func)) {
		/* See: test-bug-tailcall-preventyield-assert.c. */
		DUK_DDD(DUK_DDDPRINT("tail call prevented by function having a notail flag"));
		return 0;
	}

	/*
	 *  Tailcall handling
	 *
	 *  Although the callstack entry is reused, we need to explicitly unwind
	 *  the current activation (or simulate an unwind).  In particular, the
	 *  current activation must be closed, otherwise something like
	 *  test-bug-reduce-judofyr.js results.  Also catchers need to be unwound
	 *  because there may be non-error-catching label entries in valid tail calls.
	 *
	 *  Special attention is needed for debugger and pause behavior when
	 *  reusing an activation.
	 *    - Disable StepOut processing for the activation unwind because
	 *      we reuse the activation, see:
	 *      https://github.com/svaarala/duktape/issues/1684.
	 *    - Disable line change pause flag permanently if act == dbg_pause_act
	 *      (if set) because it would no longer be relevant, see:
	 *      https://github.com/svaarala/duktape/issues/1726,
	 *      https://github.com/svaarala/duktape/issues/1786.
	 *    - Check for function entry (e.g. StepInto) pause flag here, because
	 *      the executor pause check won't trigger due to shared activation, see:
	 *      https://github.com/svaarala/duktape/issues/1726.
	 */

	DUK_DDD(DUK_DDDPRINT("is tail call, reusing activation at callstack top, at index %ld",
                             (long) (thr->callstack_top - 1)));

	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
	DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(func));
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
	DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
	DUK_ASSERT(call_flags & DUK_CALL_FLAG_ALLOW_ECMATOECMA);

	/* Unwind the topmost callstack entry before reusing it.  This
	 * also unwinds the catchers related to the topmost entry.
	 */
	DUK_ASSERT(thr->callstack_top > 0);
	DUK_ASSERT(thr->callstack_curr != NULL);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	if (act == thr->heap->dbg_pause_act) {
		thr->heap->dbg_pause_flags &= ~DUK_PAUSE_FLAG_LINE_CHANGE;
	}

	prev_pause_act = thr->heap->dbg_pause_act;
	thr->heap->dbg_pause_act = NULL;
	if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_FUNC_ENTRY) {
		DUK_D(DUK_DPRINT("PAUSE TRIGGERED by function entry (tailcall)"));
		duk_debug_set_paused(thr->heap);
	}
#endif
	duk_hthread_activation_unwind_reuse_norz(thr);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	thr->heap->dbg_pause_act = prev_pause_act;
#endif
	DUK_ASSERT(act == thr->callstack_curr);

	/* XXX: We could restore the caller's value stack reserve
	 * here, as if we did an actual unwind-and-call.  Without
	 * the restoration, value stack reserve may remain higher
	 * than would otherwise be possible until we return to a
	 * non-tailcall.
	 */

	/* Then reuse the unwound activation. */
	act->cat = NULL;
	act->var_env = NULL;
	act->lex_env = NULL;
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
	act->func = func;  /* don't want an intermediate exposed state with func == NULL */
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	act->prev_caller = NULL;
#endif
	/* don't want an intermediate exposed state with invalid pc */
	act->curr_pc = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) func);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	act->prev_line = 0;
#endif
	DUK_TVAL_SET_OBJECT(&act->tv_func, func);  /* borrowed, no refcount */
	DUK_HOBJECT_INCREF(thr, func);

	act->flags = DUK_ACT_FLAG_TAILCALLED;
	if (DUK_HOBJECT_HAS_STRICT(func)) {
		act->flags |= DUK_ACT_FLAG_STRICT;
	}
	if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
		act->flags |= DUK_ACT_FLAG_CONSTRUCT;
	}
#if defined(DUK_USE_ES6_PROXY)
	if (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) {
		act->flags |= DUK_ACT_FLAG_CONSTRUCT_PROXY;
	}
#endif

	DUK_ASSERT(DUK_ACT_GET_FUNC(act) == func);      /* already updated */
	DUK_ASSERT(act->var_env == NULL);
	DUK_ASSERT(act->lex_env == NULL);
	act->bottom_byteoff = entry_valstack_bottom_byteoff;  /* tail call -> reuse current "frame" */
#if 0
	/* Topmost activation retval_byteoff is considered garbage, no need to init. */
	act->retval_byteoff = 0;
#endif
	/* Filled in when final reserve is known, dummy value doesn't matter
	 * even in error unwind because reserve_byteoff is only used when
	 * returning to -this- activation.
	 */
	act->reserve_byteoff = 0;

	/*
	 *  Manipulate valstack so that args are on the current bottom and the
	 *  previous caller's 'this' binding (which is the value preceding the
	 *  current bottom) is replaced with the new 'this' binding:
	 *
	 *       [ ... this_old | (crud) func this_new arg1 ... argN ]
	 *  -->  [ ... this_new | arg1 ... argN ]
	 *
	 *  For tail calling to work properly, the valstack bottom must not grow
	 *  here; otherwise crud would accumulate on the valstack.
	 */

	tv1 = thr->valstack_bottom - 1;
	tv2 = thr->valstack_bottom + idx_func + 1;
	DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top);  /* tv1 is -below- valstack_bottom */
	DUK_ASSERT(tv2 >= thr->valstack_bottom && tv2 < thr->valstack_top);
	DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects */

	idx_args = idx_func + 2;
	duk_remove_n(thr, 0, idx_args);  /* may be NORZ */

	idx_func = 0; DUK_UNREF(idx_func);  /* really 'not applicable' anymore, should not be referenced after this */
	idx_args = 0;

	*out_nargs = ((duk_hcompfunc *) func)->nargs;
	*out_nregs = ((duk_hcompfunc *) func)->nregs;
	DUK_ASSERT(*out_nregs >= 0);
	DUK_ASSERT(*out_nregs >= *out_nargs);
	*out_vs_min_bytes = entry_valstack_bottom_byteoff + sizeof(duk_tval) * ((duk_size_t) *out_nregs + DUK_VALSTACK_INTERNAL_EXTRA);


#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
#if defined(DUK_USE_TAILCALL)
#error incorrect options: tail calls enabled with function caller property
#endif
	/* XXX: This doesn't actually work properly for tail calls, so
	 * tail calls are disabled when DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
	 * is in use.
	 */
	duk__update_func_caller_prop(thr, func);
#endif

	/* [ ... this_new | arg1 ... argN ] */

	return 1;
}
#endif  /* DUK_USE_TAILCALL */

DUK_LOCAL void duk__call_setup_act_not_tailcall(duk_hthread *thr,
                                                duk_small_uint_t call_flags,
                                                duk_idx_t idx_func,
                                                duk_hobject *func,
                                                duk_size_t entry_valstack_bottom_byteoff,
                                                duk_size_t entry_valstack_end_byteoff,
                                                duk_idx_t *out_nargs,
                                                duk_idx_t *out_nregs,
                                                duk_size_t *out_vs_min_bytes,
                                                duk_activation **out_act) {
	duk_activation *act;
	duk_activation *new_act;

	DUK_UNREF(entry_valstack_end_byteoff);

	DUK_DDD(DUK_DDDPRINT("not a tail call, pushing a new activation to callstack, to index %ld",
	                     (long) (thr->callstack_top)));

	duk__call_callstack_limit_check(thr);
	new_act = duk_hthread_activation_alloc(thr);
	DUK_ASSERT(new_act != NULL);

	act = thr->callstack_curr;
	if (act != NULL) {
		/*
		 *  Update return value stack index of current activation (if any).
		 *
		 *  Although it might seem this is not necessary (bytecode executor
		 *  does this for ECMAScript-to-ECMAScript calls; other calls are
		 *  handled here), this turns out to be necessary for handling yield
		 *  and resume.  For them, an ECMAScript-to-native call happens, and
		 *  the ECMAScript call's retval_byteoff must be set for things to work.
		 */

		act->retval_byteoff = entry_valstack_bottom_byteoff + (duk_size_t) idx_func * sizeof(duk_tval);
	}

	new_act->parent = act;
	thr->callstack_curr = new_act;
	thr->callstack_top++;
	act = new_act;
	*out_act = act;

	DUK_ASSERT(thr->valstack_top > thr->valstack_bottom);  /* at least effective 'this' */
	DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));

	act->cat = NULL;

	act->flags = 0;
	if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
		act->flags |= DUK_ACT_FLAG_CONSTRUCT;
	}
#if defined(DUK_USE_ES6_PROXY)
	if (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) {
		act->flags |= DUK_ACT_FLAG_CONSTRUCT_PROXY;
	}
#endif
	if (call_flags & DUK_CALL_FLAG_DIRECT_EVAL) {
		act->flags |= DUK_ACT_FLAG_DIRECT_EVAL;
	}

	/* start of arguments: idx_func + 2. */
	act->func = func;  /* NULL for lightfunc */
	if (DUK_LIKELY(func != NULL)) {
		DUK_TVAL_SET_OBJECT(&act->tv_func, func);  /* borrowed, no refcount */
		if (DUK_HOBJECT_HAS_STRICT(func)) {
			act->flags |= DUK_ACT_FLAG_STRICT;
		}
		if (DUK_HOBJECT_IS_COMPFUNC(func)) {
			*out_nargs = ((duk_hcompfunc *) func)->nargs;
			*out_nregs = ((duk_hcompfunc *) func)->nregs;
			DUK_ASSERT(*out_nregs >= 0);
			DUK_ASSERT(*out_nregs >= *out_nargs);
			*out_vs_min_bytes = entry_valstack_bottom_byteoff +
				sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nregs + DUK_VALSTACK_INTERNAL_EXTRA);
		} else {
			/* True because of call target lookup checks. */
			DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(func));

			*out_nargs = ((duk_hnatfunc *) func)->nargs;
			*out_nregs = *out_nargs;
			if (*out_nargs >= 0) {
				*out_vs_min_bytes = entry_valstack_bottom_byteoff +
					sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nregs + DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
			} else {
				/* Vararg function. */
				duk_size_t valstack_top_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - ((duk_uint8_t *) thr->valstack));
				*out_vs_min_bytes = valstack_top_byteoff +
					sizeof(duk_tval) * (DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
			}
		}
	} else {
		duk_small_uint_t lf_flags;
		duk_tval *tv_func;

		act->flags |= DUK_ACT_FLAG_STRICT;

		tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
		DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func));
		DUK_TVAL_SET_TVAL(&act->tv_func, tv_func);  /* borrowed, no refcount */

		lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv_func);
		*out_nargs = DUK_LFUNC_FLAGS_GET_NARGS(lf_flags);
		if (*out_nargs != DUK_LFUNC_NARGS_VARARGS) {
			*out_vs_min_bytes = entry_valstack_bottom_byteoff +
				sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nargs + DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
		} else {
			duk_size_t valstack_top_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - ((duk_uint8_t *) thr->valstack));
			*out_vs_min_bytes = valstack_top_byteoff +
				sizeof(duk_tval) * (DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
			*out_nargs = -1;  /* vararg */
		}
		*out_nregs = *out_nargs;
	}

	act->var_env = NULL;
	act->lex_env = NULL;
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	act->prev_caller = NULL;
#endif
	act->curr_pc = NULL;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	act->prev_line = 0;
#endif
	act->bottom_byteoff = entry_valstack_bottom_byteoff + sizeof(duk_tval) * ((duk_size_t) idx_func + 2U);
#if 0
	act->retval_byteoff = 0;   /* topmost activation retval_byteoff is considered garbage, no need to init */
#endif
	/* Filled in when final reserve is known, dummy value doesn't matter
	 * even in error unwind because reserve_byteoff is only used when
	 * returning to -this- activation.
	 */
	act->reserve_byteoff = 0;  /* filled in by caller */

	/* XXX: Is this INCREF necessary? 'func' is always a borrowed
	 * reference reachable through the value stack?  If changed, stack
	 * unwind code also needs to be fixed to match.
	 */
	DUK_HOBJECT_INCREF_ALLOWNULL(thr, func);  /* act->func */

#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
	if (func) {
		duk__update_func_caller_prop(thr, func);
	}
#endif
}

/*
 *  Environment setup.
 */

DUK_LOCAL void duk__call_env_setup(duk_hthread *thr, duk_hobject *func, duk_activation *act, duk_idx_t idx_args) {
	duk_hobject *env;

	DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));  /* bound function has already been resolved */

	if (DUK_LIKELY(func != NULL)) {
		if (DUK_LIKELY(DUK_HOBJECT_HAS_NEWENV(func))) {
			DUK_STATS_INC(thr->heap, stats_envrec_newenv);
			if (DUK_LIKELY(!DUK_HOBJECT_HAS_CREATEARGS(func))) {
				/* Use a new environment but there's no 'arguments' object;
				 * delayed environment initialization.  This is the most
				 * common case.
				 */
				DUK_ASSERT(act->lex_env == NULL);
				DUK_ASSERT(act->var_env == NULL);
			} else {
				/* Use a new environment and there's an 'arguments' object.
				 * We need to initialize it right now.
				 */

				/* third arg: absolute index (to entire valstack) of bottom_byteoff of new activation */
				env = duk_create_activation_environment_record(thr, func, act->bottom_byteoff);
				DUK_ASSERT(env != NULL);

				/* [ ... func this arg1 ... argN envobj ] */

				DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));
				duk__handle_createargs_for_call(thr, func, env, idx_args);

				/* [ ... func this arg1 ... argN envobj ] */

				act->lex_env = env;
				act->var_env = env;
				DUK_HOBJECT_INCREF(thr, env);
				DUK_HOBJECT_INCREF(thr, env);  /* XXX: incref by count (2) directly */
				duk_pop(thr);
			}
		} else {
			/* Use existing env (e.g. for non-strict eval); cannot have
			 * an own 'arguments' object (but can refer to an existing one).
			 */

			DUK_ASSERT(!DUK_HOBJECT_HAS_CREATEARGS(func));

			DUK_STATS_INC(thr->heap, stats_envrec_oldenv);
			duk__handle_oldenv_for_call(thr, func, act);

			DUK_ASSERT(act->lex_env != NULL);
			DUK_ASSERT(act->var_env != NULL);
		}
	} else {
		/* Lightfuncs are always native functions and have "newenv". */
		DUK_ASSERT(act->lex_env == NULL);
		DUK_ASSERT(act->var_env == NULL);
		DUK_STATS_INC(thr->heap, stats_envrec_newenv);
	}
}

/*
 *  Misc shared helpers.
 */

/* Check thread state, update current thread. */
DUK_LOCAL void duk__call_thread_state_update(duk_hthread *thr) {
	DUK_ASSERT(thr != NULL);

	if (DUK_LIKELY(thr == thr->heap->curr_thread)) {
		if (DUK_UNLIKELY(thr->state != DUK_HTHREAD_STATE_RUNNING)) {
			/* Should actually never happen, but check anyway. */
			goto thread_state_error;
		}
	} else {
		DUK_ASSERT(thr->heap->curr_thread == NULL ||
		           thr->heap->curr_thread->state == DUK_HTHREAD_STATE_RUNNING);
		if (DUK_UNLIKELY(thr->state != DUK_HTHREAD_STATE_INACTIVE)) {
			goto thread_state_error;
		}
		DUK_HEAP_SWITCH_THREAD(thr->heap, thr);
		thr->state = DUK_HTHREAD_STATE_RUNNING;

		/* Multiple threads may be simultaneously in the RUNNING
		 * state, but not in the same "resume chain".
		 */
	}
	DUK_ASSERT(thr->heap->curr_thread == thr);
	DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
	return;

 thread_state_error:
	DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "invalid thread state (%ld)", (long) thr->state);
	DUK_WO_NORETURN(return;);
}

/*
 *  Main unprotected call handler, handles:
 *
 *    - All combinations of native/ECMAScript caller and native/ECMAScript
 *      target.
 *
 *    - Optimized ECMAScript-to-ECMAScript call where call handling only
 *      sets up a new duk_activation but reuses an existing bytecode executor
 *      (the caller) without native recursion.
 *
 *    - Tailcalls, where an activation is reused without increasing call
 *      stack (duk_activation) depth.
 *
 *    - Setup for an initial Duktape.Thread.resume().
 *
 *  The call handler doesn't provide any protection guarantees, protected calls
 *  must be implemented e.g. by wrapping the call in a duk_safe_call().
 *  Call setup may fail at any stage, even when the new activation is in
 *  place; the only guarantee is that the state is consistent for unwinding.
 */

DUK_LOCAL duk_int_t duk__handle_call_raw(duk_hthread *thr,
                                         duk_idx_t idx_func,
                                         duk_small_uint_t call_flags) {
#if defined(DUK_USE_ASSERTIONS)
	duk_activation *entry_act;
	duk_size_t entry_callstack_top;
#endif
	duk_size_t entry_valstack_bottom_byteoff;
	duk_size_t entry_valstack_end_byteoff;
	duk_int_t entry_call_recursion_depth;
	duk_hthread *entry_curr_thread;
	duk_uint_fast8_t entry_thread_state;
	duk_instr_t **entry_ptr_curr_pc;
	duk_idx_t idx_args;
	duk_idx_t nargs;            /* # argument registers target function wants (< 0 => "as is") */
	duk_idx_t nregs;            /* # total registers target function wants on entry (< 0 => "as is") */
	duk_size_t vs_min_bytes;    /* minimum value stack size (bytes) for handling call */
	duk_hobject *func;          /* 'func' on stack (borrowed reference) */
	duk_activation *act;
	duk_ret_t rc;
	duk_small_uint_t use_tailcall;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	/* Asserts for heap->curr_thread omitted: it may be NULL, 'thr', or
	 * any other thread (e.g. when heap thread is used to run finalizers).
	 */
	DUK_CTX_ASSERT_VALID(thr);
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));
	DUK_ASSERT(idx_func >= 0);

	DUK_STATS_INC(thr->heap, stats_call_all);

	/* If a tail call:
	 *   - an ECMAScript activation must be on top of the callstack
	 *   - there cannot be any catch stack entries that would catch
	 *     a return
	 */
#if defined(DUK_USE_ASSERTIONS)
	if (call_flags & DUK_CALL_FLAG_TAILCALL) {
		duk_activation *tmp_act;
		duk_catcher *tmp_cat;

		DUK_ASSERT(thr->callstack_top >= 1);
		DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));

		/* No entry in the catch stack which would actually catch a
		 * throw can refer to the callstack entry being reused.
		 * There *can* be catch stack entries referring to the current
		 * callstack entry as long as they don't catch (e.g. label sites).
		 */

		tmp_act = thr->callstack_curr;
		for (tmp_cat = tmp_act->cat; tmp_cat != NULL; tmp_cat = tmp_cat->parent) {
			DUK_ASSERT(DUK_CAT_GET_TYPE(tmp_cat) == DUK_CAT_TYPE_LABEL); /* a non-catching entry */
		}
	}
#endif  /* DUK_USE_ASSERTIONS */

	/*
	 *  Store entry state.
	 */

#if defined(DUK_USE_ASSERTIONS)
	entry_act = thr->callstack_curr;
	entry_callstack_top = thr->callstack_top;
#endif
	entry_valstack_bottom_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack);
	entry_valstack_end_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
	entry_call_recursion_depth = thr->heap->call_recursion_depth;
	entry_curr_thread = thr->heap->curr_thread;  /* may be NULL if first call */
	entry_thread_state = thr->state;
	entry_ptr_curr_pc = thr->ptr_curr_pc;  /* may be NULL */

	/* If thr->ptr_curr_pc is set, sync curr_pc to act->pc.  Then NULL
	 * thr->ptr_curr_pc so that it's not accidentally used with an incorrect
	 * activation when side effects occur.
	 */
	duk_hthread_sync_and_null_currpc(thr);
	DUK_ASSERT(thr->ptr_curr_pc == NULL);

	DUK_DD(DUK_DDPRINT("duk__handle_call_raw: thr=%p, idx_func=%ld, "
	                   "call_flags=0x%08lx (constructor=%ld), "
	                   "valstack_top=%ld, idx_func=%ld, idx_args=%ld, rec_depth=%ld/%ld, "
	                   "entry_valstack_bottom_byteoff=%ld, entry_valstack_end_byteoff=%ld, "
	                   "entry_call_recursion_depth=%ld, "
	                   "entry_curr_thread=%p, entry_thread_state=%ld",
	                   (void *) thr,
	                   (long) idx_func,
	                   (unsigned long) call_flags,
	                   (long) ((call_flags & DUK_CALL_FLAG_CONSTRUCT) != 0 ? 1 : 0),
	                   (long) duk_get_top(thr),
	                   (long) idx_func,
	                   (long) (idx_func + 2),
	                   (long) thr->heap->call_recursion_depth,
	                   (long) thr->heap->call_recursion_limit,
	                   (long) entry_valstack_bottom_byteoff,
	                   (long) entry_valstack_end_byteoff,
	                   (long) entry_call_recursion_depth,
	                   (void *) entry_curr_thread,
	                   (long) entry_thread_state));

	/*
	 *  Thread state check and book-keeping.
	 */

	duk__call_thread_state_update(thr);

	/*
	 *  Increase call recursion depth as early as possible so that if we
	 *  enter a recursive call for any reason there's a backstop to native
	 *  recursion.  This can happen e.g. for almost any property read
	 *  because it may cause a getter call or a Proxy trap (GC and finalizers
	 *  are not an issue because they are not recursive).  If we end up
	 *  doing an Ecma-to-Ecma call, revert the increase.  (See GH-2032.)
	 *
	 *  For similar reasons, ensure there is a known value stack spare
	 *  even before we actually prepare the value stack for the target
	 *  function.  If this isn't done, early recursion may consume the
	 *  value stack space.
	 *
	 *  XXX: Should bump yield preventcount early, for the same reason.
	 */

	duk__call_c_recursion_limit_check(thr);
	thr->heap->call_recursion_depth++;
	duk_require_stack(thr, DUK__CALL_HANDLING_REQUIRE_STACK);

	/*
	 *  Resolve final target function; handle bound functions and special
	 *  functions like .call() and .apply().  Also figure out the effective
	 *  'this' binding, which replaces the current value at idx_func + 1.
	 */

	if (DUK_LIKELY(duk__resolve_target_fastpath_check(thr, idx_func, &func, call_flags) != 0U)) {
		DUK_DDD(DUK_DDDPRINT("fast path target resolve"));
	} else {
		DUK_DDD(DUK_DDDPRINT("slow path target resolve"));
		func = duk__resolve_target_func_and_this_binding(thr, idx_func, &call_flags);
	}
	DUK_ASSERT(duk_get_top(thr) - idx_func >= 2);  /* at least func and this present */

	DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
	DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
	                            DUK_HOBJECT_IS_NATFUNC(func)));

	/* [ ... func this arg1 ... argN ] */

	/*
	 *  Setup a preliminary activation and figure out nargs/nregs and
	 *  value stack minimum size.
	 *
	 *  Don't touch valstack_bottom or valstack_top yet so that Duktape API
	 *  calls work normally.
	 *
	 *  Because 'act' is not zeroed, all fields must be filled in.
	 */

	/* Should not be necessary, but initialize to silence warnings. */
	act = NULL;
	nargs = 0;
	nregs = 0;
	vs_min_bytes = 0;

#if defined(DUK_USE_TAILCALL)
	use_tailcall = (call_flags & DUK_CALL_FLAG_TAILCALL);
	if (use_tailcall) {
		use_tailcall = duk__call_setup_act_attempt_tailcall(thr,
		                                                    call_flags,
		                                                    idx_func,
		                                                    func,
		                                                    entry_valstack_bottom_byteoff,
		                                                    entry_valstack_end_byteoff,
		                                                    &nargs,
		                                                    &nregs,
		                                                    &vs_min_bytes,
		                                                    &act);
	}
#else
	DUK_ASSERT((call_flags & DUK_CALL_FLAG_TAILCALL) == 0);  /* compiler ensures this */
	use_tailcall = 0;
#endif

	if (use_tailcall) {
		idx_args = 0;
		DUK_STATS_INC(thr->heap, stats_call_tailcall);
	} else {
		duk__call_setup_act_not_tailcall(thr,
		                                 call_flags,
		                                 idx_func,
		                                 func,
		                                 entry_valstack_bottom_byteoff,
		                                 entry_valstack_end_byteoff,
		                                 &nargs,
		                                 &nregs,
		                                 &vs_min_bytes,
		                                 &act);
		idx_args = idx_func + 2;
	}
	/* After this point idx_func is no longer valid for tailcalls. */

	DUK_ASSERT(act != NULL);

	/* [ ... func this arg1 ... argN ] */

	/*
	 *  Environment record creation and 'arguments' object creation.
	 *  Named function expression name binding is handled by the
	 *  compiler; the compiled function's parent env will contain
	 *  the (immutable) binding already.
	 *
	 *  This handling is now identical for C and ECMAScript functions.
	 *  C functions always have the 'NEWENV' flag set, so their
	 *  environment record initialization is delayed (which is good).
	 *
	 *  Delayed creation (on demand) is handled in duk_js_var.c.
	 */

	duk__call_env_setup(thr, func, act, idx_args);

	/* [ ... func this arg1 ... argN ] */

	/*
	 *  Setup value stack: clamp to 'nargs', fill up to 'nregs',
	 *  ensure value stack size matches target requirements, and
	 *  switch value stack bottom.  Valstack top is kept.
	 *
	 *  Value stack can only grow here.
	 */

	duk_valstack_grow_check_throw(thr, vs_min_bytes);
	act->reserve_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);

	if (use_tailcall) {
		DUK_ASSERT(nregs >= 0);
		DUK_ASSERT(nregs >= nargs);
		duk_set_top_and_wipe(thr, nregs, nargs);
	} else {
		if (nregs >= 0) {
			DUK_ASSERT(nregs >= nargs);
			duk_set_top_and_wipe(thr, idx_func + 2 + nregs, idx_func + 2 + nargs);
		} else {
			;
		}
		thr->valstack_bottom = thr->valstack_bottom + idx_func + 2;
	}
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);

	/*
	 *  Make the actual call.  For Ecma-to-Ecma calls detect that
	 *  setup is complete, then return with a status code that allows
	 *  the caller to reuse the running executor.
	 */

	if (func != NULL && DUK_HOBJECT_IS_COMPFUNC(func)) {
		/*
		 *  ECMAScript call.
		 */

		DUK_ASSERT(func != NULL);
		DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
		act->curr_pc = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) func);

		if (call_flags & DUK_CALL_FLAG_ALLOW_ECMATOECMA) {
			DUK_DD(DUK_DDPRINT("avoid native call, use existing executor"));
			DUK_STATS_INC(thr->heap, stats_call_ecmatoecma);
			DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
			DUK_REFZERO_CHECK_FAST(thr);
			DUK_ASSERT(thr->ptr_curr_pc == NULL);
			thr->heap->call_recursion_depth--;  /* No recursion increase for this case. */
			return 1;  /* 1=reuse executor */
		}
		DUK_ASSERT(use_tailcall == 0);

		/* duk_hthread_activation_unwind_norz() will decrease this on unwind */
		DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
		act->flags |= DUK_ACT_FLAG_PREVENT_YIELD;
		thr->callstack_preventcount++;

		/* [ ... func this | arg1 ... argN ] ('this' must precede new bottom) */

		/*
		 *  Bytecode executor call.
		 *
		 *  Execute bytecode, handling any recursive function calls and
		 *  thread resumptions.  Returns when execution would return from
		 *  the entry level activation.  When the executor returns, a
		 *  single return value is left on the stack top.
		 *
		 *  The only possible longjmp() is an error (DUK_LJ_TYPE_THROW),
		 *  other types are handled internally by the executor.
		 */

		/* thr->ptr_curr_pc is set by bytecode executor early on entry */
		DUK_ASSERT(thr->ptr_curr_pc == NULL);
		DUK_DDD(DUK_DDDPRINT("entering bytecode execution"));
		duk_js_execute_bytecode(thr);
		DUK_DDD(DUK_DDDPRINT("returned from bytecode execution"));
	} else {
		/*
		 *  Native call.
		 */

		DUK_ASSERT(func == NULL || ((duk_hnatfunc *) func)->func != NULL);
		DUK_ASSERT(use_tailcall == 0);

		/* [ ... func this | arg1 ... argN ] ('this' must precede new bottom) */

		/* duk_hthread_activation_unwind_norz() will decrease this on unwind */
		DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
		act->flags |= DUK_ACT_FLAG_PREVENT_YIELD;
		thr->callstack_preventcount++;

		/* For native calls must be NULL so we don't sync back */
		DUK_ASSERT(thr->ptr_curr_pc == NULL);

		/* XXX: native funcptr could come out of call setup. */
		if (func) {
			rc = ((duk_hnatfunc *) func)->func(thr);
		} else {
			duk_tval *tv_func;
			duk_c_function funcptr;

			tv_func = &act->tv_func;
			DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func));
			funcptr = DUK_TVAL_GET_LIGHTFUNC_FUNCPTR(tv_func);
			rc = funcptr(thr);
		}

		/* Automatic error throwing, retval check. */

		if (rc == 0) {
			DUK_ASSERT(thr->valstack < thr->valstack_end);
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));
			thr->valstack_top++;
		} else if (rc == 1) {
			;
		} else if (rc < 0) {
			duk_error_throw_from_negative_rc(thr, rc);
			DUK_WO_NORETURN(return 0;);
		} else {
			DUK_ERROR_TYPE(thr, DUK_STR_INVALID_CFUNC_RC);
			DUK_WO_NORETURN(return 0;);
		}
	}
	DUK_ASSERT(thr->ptr_curr_pc == NULL);
	DUK_ASSERT(use_tailcall == 0);

	/*
	 *  Constructor call post processing.
	 */

#if defined(DUK_USE_ES6_PROXY)
	if (call_flags & (DUK_CALL_FLAG_CONSTRUCT | DUK_CALL_FLAG_CONSTRUCT_PROXY)) {
		duk_call_construct_postprocess(thr, call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY);
	}
#else
	if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
		duk_call_construct_postprocess(thr, 0);
	}
#endif

	/*
	 *  Unwind, restore valstack bottom and other book-keeping.
	 */

	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(thr->callstack_curr->parent == entry_act);
	DUK_ASSERT(thr->callstack_top == entry_callstack_top + 1);
	duk_hthread_activation_unwind_norz(thr);
	DUK_ASSERT(thr->callstack_curr == entry_act);
	DUK_ASSERT(thr->callstack_top == entry_callstack_top);

	thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_bottom_byteoff);
	/* keep current valstack_top */
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
	DUK_ASSERT(thr->valstack_top - thr->valstack_bottom >= idx_func + 1);

	/* Return value handling. */

	/* [ ... func this (crud) retval ] */

	{
		duk_tval *tv_ret;
		duk_tval *tv_funret;

		tv_ret = thr->valstack_bottom + idx_func;
		tv_funret = thr->valstack_top - 1;
#if defined(DUK_USE_FASTINT)
		/* Explicit check for fastint downgrade. */
		DUK_TVAL_CHKFAST_INPLACE_FAST(tv_funret);
#endif
		DUK_TVAL_SET_TVAL_UPDREF(thr, tv_ret, tv_funret);  /* side effects */
	}

	duk_set_top_unsafe(thr, idx_func + 1);

	/* [ ... retval ] */

	/* Restore caller's value stack reserve (cannot fail). */
	DUK_ASSERT((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff >= (duk_uint8_t *) thr->valstack_top);
	DUK_ASSERT((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff <= (duk_uint8_t *) thr->valstack_alloc_end);
	thr->valstack_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff);

	/* XXX: Trial value stack shrink would be OK here, but we'd need
	 * to prevent side effects of the potential realloc.
	 */

	/* Restore entry thread executor curr_pc stack frame pointer. */
	thr->ptr_curr_pc = entry_ptr_curr_pc;

	DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread);  /* may be NULL */
	thr->state = (duk_uint8_t) entry_thread_state;

	/* Disabled assert: triggered with some torture tests. */
#if 0
	DUK_ASSERT((thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread == NULL) ||  /* first call */
	           (thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread != NULL) ||  /* other call */
	           (thr->state == DUK_HTHREAD_STATE_RUNNING && thr->heap->curr_thread == thr));     /* current thread */
#endif

	thr->heap->call_recursion_depth = entry_call_recursion_depth;

	/* If the debugger is active we need to force an interrupt so that
	 * debugger breakpoints are rechecked.  This is important for function
	 * calls caused by side effects (e.g. when doing a DUK_OP_GETPROP), see
	 * GH-303.  Only needed for success path, error path always causes a
	 * breakpoint recheck in the executor.  It would be enough to set this
	 * only when returning to an ECMAScript activation, but setting the flag
	 * on every return should have no ill effect.
	 */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	if (duk_debug_is_attached(thr->heap)) {
		DUK_DD(DUK_DDPRINT("returning with debugger enabled, force interrupt"));
		DUK_ASSERT(thr->interrupt_counter <= thr->interrupt_init);
		thr->interrupt_init -= thr->interrupt_counter;
		thr->interrupt_counter = 0;
		thr->heap->dbg_force_restart = 1;
	}
#endif

#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
	duk__interrupt_fixup(thr, entry_curr_thread);
#endif

	/* Restored by success path. */
	DUK_ASSERT(thr->heap->call_recursion_depth == entry_call_recursion_depth);
	DUK_ASSERT(thr->ptr_curr_pc == entry_ptr_curr_pc);
	DUK_ASSERT_LJSTATE_UNSET(thr->heap);

	DUK_REFZERO_CHECK_FAST(thr);

	return 0;  /* 0=call handled inline */
}

DUK_INTERNAL duk_int_t duk_handle_call_unprotected_nargs(duk_hthread *thr,
                                                         duk_idx_t nargs,
                                                         duk_small_uint_t call_flags) {
	duk_idx_t idx_func;
	DUK_ASSERT(duk_get_top(thr) >= nargs + 2);
	idx_func = duk_get_top(thr) - (nargs + 2);
	DUK_ASSERT(idx_func >= 0);
	return duk_handle_call_unprotected(thr, idx_func, call_flags);
}

DUK_INTERNAL duk_int_t duk_handle_call_unprotected(duk_hthread *thr,
                                                   duk_idx_t idx_func,
                                                   duk_small_uint_t call_flags) {
	DUK_ASSERT(duk_is_valid_index(thr, idx_func));
	DUK_ASSERT(idx_func >= 0);
	return duk__handle_call_raw(thr, idx_func, call_flags);
}

/*
 *  duk_handle_safe_call(): make a "C protected call" within the
 *  current activation.
 *
 *  The allowed thread states for making a call are the same as for
 *  duk_handle_call_protected().
 *
 *  Even though this call is protected, errors are thrown for insane arguments
 *  and may result in a fatal error unless there's another protected call which
 *  catches such errors.
 *
 *  The error handling path should be error free, even for out-of-memory
 *  errors, to ensure safe sandboxing.  (As of Duktape 2.2.0 this is not
 *  yet the case for environment closing which may run out of memory, see
 *  XXX notes below.)
 */

DUK_LOCAL void duk__handle_safe_call_inner(duk_hthread *thr,
                                           duk_safe_call_function func,
                                           void *udata,
#if defined(DUK_USE_ASSERTIONS)
                                           duk_size_t entry_valstack_bottom_byteoff,
                                           duk_size_t entry_callstack_top,
#endif
                                           duk_hthread *entry_curr_thread,
                                           duk_uint_fast8_t entry_thread_state,
                                           duk_idx_t idx_retbase,
                                           duk_idx_t num_stack_rets) {
	duk_ret_t rc;

	DUK_ASSERT(thr != NULL);
	DUK_CTX_ASSERT_VALID(thr);

	/*
	 *  Thread state check and book-keeping.
	 */

	duk__call_thread_state_update(thr);

	/*
	 *  Recursion limit check.
	 */

	duk__call_c_recursion_limit_check(thr);
	thr->heap->call_recursion_depth++;

	/*
	 *  Make the C call.
	 */

	rc = func(thr, udata);

	DUK_DDD(DUK_DDDPRINT("safe_call, func rc=%ld", (long) rc));

	/*
	 *  Valstack manipulation for results.
	 */

	/* we're running inside the caller's activation, so no change in call/catch stack or valstack bottom */
	DUK_ASSERT(thr->callstack_top == entry_callstack_top);
	DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
	DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) == entry_valstack_bottom_byteoff);
	DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
	DUK_ASSERT(thr->valstack_end >= thr->valstack_top);

	if (DUK_UNLIKELY(rc < 0)) {
		duk_error_throw_from_negative_rc(thr, rc);
		DUK_WO_NORETURN(return;);
	}
	DUK_ASSERT(rc >= 0);

	duk__safe_call_adjust_valstack(thr, idx_retbase, num_stack_rets, rc);  /* throws for insane rc */

	DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread);  /* may be NULL */
	thr->state = (duk_uint8_t) entry_thread_state;
}

DUK_LOCAL void duk__handle_safe_call_error(duk_hthread *thr,
                                           duk_activation *entry_act,
#if defined(DUK_USE_ASSERTIONS)
                                           duk_size_t entry_callstack_top,
#endif
                                           duk_hthread *entry_curr_thread,
                                           duk_uint_fast8_t entry_thread_state,
                                           duk_idx_t idx_retbase,
                                           duk_idx_t num_stack_rets,
                                           duk_size_t entry_valstack_bottom_byteoff,
                                           duk_jmpbuf *old_jmpbuf_ptr) {
	DUK_ASSERT(thr != NULL);
	DUK_CTX_ASSERT_VALID(thr);

	/*
	 *  Error during call.  The error value is at heap->lj.value1.
	 *
	 *  The very first thing we do is restore the previous setjmp catcher.
	 *  This means that any error in error handling will propagate outwards
	 *  instead of causing a setjmp() re-entry above.
	 */

	DUK_DDD(DUK_DDDPRINT("error caught during protected duk_handle_safe_call()"));

	/* Other longjmp types are handled by executor before propagating
	 * the error here.
	 */
	DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_THROW);
	DUK_ASSERT_LJSTATE_SET(thr->heap);

	/* Either pointer may be NULL (at entry), so don't assert. */
	thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;

	/* XXX: callstack unwind may now throw an error when closing
	 * scopes; this is a sandboxing issue, described in:
	 * https://github.com/svaarala/duktape/issues/476
	 */
	/* XXX: "unwind to" primitive? */

	DUK_ASSERT(thr->callstack_top >= entry_callstack_top);
	while (thr->callstack_curr != entry_act) {
		DUK_ASSERT(thr->callstack_curr != NULL);
		duk_hthread_activation_unwind_norz(thr);
	}
	DUK_ASSERT(thr->callstack_top == entry_callstack_top);

	/* Switch active thread before any side effects to avoid a
	 * dangling curr_thread pointer.
	 */
	DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread);  /* may be NULL */
	thr->state = (duk_uint8_t) entry_thread_state;

	DUK_ASSERT(thr->heap->curr_thread == entry_curr_thread);
	DUK_ASSERT(thr->state == entry_thread_state);

	/* Restore valstack bottom. */
	thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_bottom_byteoff);

	/* [ ... | (crud) ] */

	/* XXX: ensure space in valstack (now relies on internal reserve)? */
	duk_push_tval(thr, &thr->heap->lj.value1);

	/* [ ... | (crud) errobj ] */

	DUK_ASSERT(duk_get_top(thr) >= 1);  /* at least errobj must be on stack */

	duk__safe_call_adjust_valstack(thr, idx_retbase, num_stack_rets, 1);  /* 1 = num actual 'return values' */

	/* [ ... | ] or [ ... | errobj (M * undefined)] where M = num_stack_rets - 1 */

	/* Reset longjmp state. */
	thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
	thr->heap->lj.iserror = 0;
	DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, &thr->heap->lj.value1);
	DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, &thr->heap->lj.value2);

	/* Error handling complete, remove side effect protections.  Caller
	 * will process pending finalizers.
	 */
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(thr->heap->error_not_allowed == 1);
	thr->heap->error_not_allowed = 0;
#endif
	DUK_ASSERT(thr->heap->pf_prevent_count > 0);
	thr->heap->pf_prevent_count--;
	DUK_DD(DUK_DDPRINT("safe call error handled, pf_prevent_count updated to %ld", (long) thr->heap->pf_prevent_count));

	/* thr->ptr_curr_pc is restored by
	 * duk__handle_safe_call_shared_unwind() which is also used for
	 * success path.
	 */
}

DUK_LOCAL void duk__handle_safe_call_shared_unwind(duk_hthread *thr,
                                                   duk_idx_t idx_retbase,
                                                   duk_idx_t num_stack_rets,
#if defined(DUK_USE_ASSERTIONS)
                                                   duk_size_t entry_callstack_top,
#endif
                                                   duk_int_t entry_call_recursion_depth,
                                                   duk_hthread *entry_curr_thread,
                                                   duk_instr_t **entry_ptr_curr_pc) {
	DUK_ASSERT(thr != NULL);
	DUK_CTX_ASSERT_VALID(thr);
	DUK_UNREF(idx_retbase);
	DUK_UNREF(num_stack_rets);
	DUK_UNREF(entry_curr_thread);

	DUK_ASSERT(thr->callstack_top == entry_callstack_top);

	/* Restore entry thread executor curr_pc stack frame pointer.
	 * XXX: would be enough to do in error path only, should nest
	 * cleanly in success path.
	 */
	thr->ptr_curr_pc = entry_ptr_curr_pc;

	thr->heap->call_recursion_depth = entry_call_recursion_depth;

	/* stack discipline consistency check */
	DUK_ASSERT(duk_get_top(thr) == idx_retbase + num_stack_rets);

	/* A debugger forced interrupt check is not needed here, as
	 * problematic safe calls are not caused by side effects.
	 */

#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
	duk__interrupt_fixup(thr, entry_curr_thread);
#endif
}

DUK_INTERNAL duk_int_t duk_handle_safe_call(duk_hthread *thr,
                                            duk_safe_call_function func,
                                            void *udata,
                                            duk_idx_t num_stack_args,
                                            duk_idx_t num_stack_rets) {
	duk_activation *entry_act;
	duk_size_t entry_valstack_bottom_byteoff;
#if defined(DUK_USE_ASSERTIONS)
	duk_size_t entry_valstack_end_byteoff;
	duk_size_t entry_callstack_top;
	duk_size_t entry_callstack_preventcount;
#endif
	duk_int_t entry_call_recursion_depth;
	duk_hthread *entry_curr_thread;
	duk_uint_fast8_t entry_thread_state;
	duk_instr_t **entry_ptr_curr_pc;
	duk_jmpbuf *old_jmpbuf_ptr = NULL;
	duk_jmpbuf our_jmpbuf;
	duk_idx_t idx_retbase;
	duk_int_t retval;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(duk_get_top(thr) >= num_stack_args);  /* Caller ensures. */

	DUK_STATS_INC(thr->heap, stats_safecall_all);

	/* Value stack reserve handling: safe call assumes caller has reserved
	 * space for nrets (assuming optimal unwind processing).  Value stack
	 * reserve is not stored/restored as for normal calls because a safe
	 * call conceptually happens in the same activation.
	 */

	/* Careful with indices like '-x'; if 'x' is zero, it refers to bottom */
	entry_act = thr->callstack_curr;
	entry_valstack_bottom_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack);
#if defined(DUK_USE_ASSERTIONS)
	entry_valstack_end_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
	entry_callstack_top = thr->callstack_top;
	entry_callstack_preventcount = thr->callstack_preventcount;
#endif
	entry_call_recursion_depth = thr->heap->call_recursion_depth;
	entry_curr_thread = thr->heap->curr_thread;  /* may be NULL if first call */
	entry_thread_state = thr->state;
	entry_ptr_curr_pc = thr->ptr_curr_pc;  /* may be NULL */
	idx_retbase = duk_get_top(thr) - num_stack_args;  /* not a valid stack index if num_stack_args == 0 */
	DUK_ASSERT(idx_retbase >= 0);

	DUK_ASSERT((duk_idx_t) (thr->valstack_top - thr->valstack_bottom) >= num_stack_args);  /* Caller ensures. */
	DUK_ASSERT((duk_idx_t) (thr->valstack_end - (thr->valstack_bottom + idx_retbase)) >= num_stack_rets);  /* Caller ensures. */

	/* Cannot portably debug print a function pointer, hence 'func' not printed! */
	DUK_DD(DUK_DDPRINT("duk_handle_safe_call: thr=%p, num_stack_args=%ld, num_stack_rets=%ld, "
	                   "valstack_top=%ld, idx_retbase=%ld, rec_depth=%ld/%ld, "
	                   "entry_act=%p, entry_valstack_bottom_byteoff=%ld, entry_call_recursion_depth=%ld, "
	                   "entry_curr_thread=%p, entry_thread_state=%ld",
	                   (void *) thr,
	                   (long) num_stack_args,
	                   (long) num_stack_rets,
	                   (long) duk_get_top(thr),
	                   (long) idx_retbase,
	                   (long) thr->heap->call_recursion_depth,
	                   (long) thr->heap->call_recursion_limit,
	                   (void *) entry_act,
	                   (long) entry_valstack_bottom_byteoff,
	                   (long) entry_call_recursion_depth,
	                   (void *) entry_curr_thread,
	                   (long) entry_thread_state));

	/* Setjmp catchpoint setup. */
	old_jmpbuf_ptr = thr->heap->lj.jmpbuf_ptr;
	thr->heap->lj.jmpbuf_ptr = &our_jmpbuf;

	/* Prevent yields for the duration of the safe call.  This only
	 * matters if the executor makes safe calls to functions that
	 * yield, this doesn't currently happen.
	 */
	thr->callstack_preventcount++;

#if defined(DUK_USE_CPP_EXCEPTIONS)
	try {
#else
	DUK_ASSERT(thr->heap->lj.jmpbuf_ptr == &our_jmpbuf);
	if (DUK_SETJMP(our_jmpbuf.jb) == 0) {
		/* Success path. */
#endif
		DUK_DDD(DUK_DDDPRINT("safe_call setjmp catchpoint setup complete"));

		duk__handle_safe_call_inner(thr,
		                            func,
		                            udata,
#if defined(DUK_USE_ASSERTIONS)
		                            entry_valstack_bottom_byteoff,
		                            entry_callstack_top,
#endif
		                            entry_curr_thread,
		                            entry_thread_state,
		                            idx_retbase,
		                            num_stack_rets);

		DUK_STATS_INC(thr->heap, stats_safecall_nothrow);

		/* Either pointer may be NULL (at entry), so don't assert */
		thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;

		/* If calls happen inside the safe call, these are restored by
		 * whatever calls are made.  Reserve cannot decrease.
		 */
		DUK_ASSERT(thr->callstack_curr == entry_act);
		DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);

		retval = DUK_EXEC_SUCCESS;
#if defined(DUK_USE_CPP_EXCEPTIONS)
	} catch (duk_internal_exception &exc) {
		DUK_UNREF(exc);
#else
	} else {
		/* Error path. */
#endif
		DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);

		DUK_STATS_INC(thr->heap, stats_safecall_throw);

		duk__handle_safe_call_error(thr,
		                            entry_act,
#if defined(DUK_USE_ASSERTIONS)
		                            entry_callstack_top,
#endif
		                            entry_curr_thread,
		                            entry_thread_state,
		                            idx_retbase,
		                            num_stack_rets,
		                            entry_valstack_bottom_byteoff,
		                            old_jmpbuf_ptr);

		retval = DUK_EXEC_ERROR;
	}
#if defined(DUK_USE_CPP_EXCEPTIONS)
	catch (duk_fatal_exception &exc) {
		DUK_D(DUK_DPRINT("rethrow duk_fatal_exception"));
		DUK_UNREF(exc);
		throw;
	} catch (std::exception &exc) {
		const char *what = exc.what();
		DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
		DUK_STATS_INC(thr->heap, stats_safecall_throw);
		if (!what) {
			what = "unknown";
		}
		DUK_D(DUK_DPRINT("unexpected c++ std::exception (perhaps thrown by user code)"));
		try {
			DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "caught invalid c++ std::exception '%s' (perhaps thrown by user code)", what);
			DUK_WO_NORETURN(return 0;);
		} catch (duk_internal_exception exc) {
			DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ std::exception"));
			DUK_UNREF(exc);
			duk__handle_safe_call_error(thr,
			                            entry_act,
#if defined(DUK_USE_ASSERTIONS)
			                            entry_callstack_top,
#endif
			                            entry_curr_thread,
			                            entry_thread_state,
			                            idx_retbase,
			                            num_stack_rets,
			                            entry_valstack_bottom_byteoff,
			                            old_jmpbuf_ptr);
			retval = DUK_EXEC_ERROR;
		}
	} catch (...) {
		DUK_D(DUK_DPRINT("unexpected c++ exception (perhaps thrown by user code)"));
		DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
		DUK_STATS_INC(thr->heap, stats_safecall_throw);
		try {
			DUK_ERROR_TYPE(thr, "caught invalid c++ exception (perhaps thrown by user code)");
			DUK_WO_NORETURN(return 0;);
		} catch (duk_internal_exception exc) {
			DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ exception"));
			DUK_UNREF(exc);
			duk__handle_safe_call_error(thr,
			                            entry_act,
#if defined(DUK_USE_ASSERTIONS)
			                            entry_callstack_top,
#endif
			                            entry_curr_thread,
			                            entry_thread_state,
			                            idx_retbase,
			                            num_stack_rets,
			                            entry_valstack_bottom_byteoff,
			                            old_jmpbuf_ptr);
			retval = DUK_EXEC_ERROR;
		}
	}
#endif

	DUK_ASSERT(thr->heap->lj.jmpbuf_ptr == old_jmpbuf_ptr);  /* success/error path both do this */

	DUK_ASSERT_LJSTATE_UNSET(thr->heap);

	DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
	duk__handle_safe_call_shared_unwind(thr,
	                                    idx_retbase,
	                                    num_stack_rets,
#if defined(DUK_USE_ASSERTIONS)
	                                    entry_callstack_top,
#endif
	                                    entry_call_recursion_depth,
	                                    entry_curr_thread,
	                                    entry_ptr_curr_pc);

	/* Restore preventcount. */
	thr->callstack_preventcount--;
	DUK_ASSERT(thr->callstack_preventcount == entry_callstack_preventcount);

	/* Final asserts. */
	DUK_ASSERT(thr->callstack_curr == entry_act);
	DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) == entry_valstack_bottom_byteoff);
	DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
	DUK_ASSERT(thr->callstack_top == entry_callstack_top);
	DUK_ASSERT(thr->heap->call_recursion_depth == entry_call_recursion_depth);
	DUK_ASSERT(thr->heap->curr_thread == entry_curr_thread);
	DUK_ASSERT(thr->state == entry_thread_state);
	DUK_ASSERT(thr->ptr_curr_pc == entry_ptr_curr_pc);
	DUK_ASSERT(duk_get_top(thr) == idx_retbase + num_stack_rets);
	DUK_ASSERT_LJSTATE_UNSET(thr->heap);

	/* Pending side effects. */
	DUK_REFZERO_CHECK_FAST(thr);

	return retval;
}

/*
 *  Property-based call (foo.noSuch()) error setup: replace target function
 *  on stack top with a hidden Symbol tagged non-callable wrapper object
 *  holding the error.  The error gets thrown in call handling at the
 *  proper spot to follow ECMAScript semantics.
 */

#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_INTERNAL DUK_NOINLINE DUK_COLD void duk_call_setup_propcall_error(duk_hthread *thr, duk_tval *tv_base, duk_tval *tv_key) {
	const char *str_targ, *str_key, *str_base;
	duk_idx_t entry_top;

	entry_top = duk_get_top(thr);

	/* [ <nargs> target ] */

	/* Must stabilize pointers first.  tv_targ is already on stack top. */
	duk_push_tval(thr, tv_base);
	duk_push_tval(thr, tv_key);

	DUK_GC_TORTURE(thr->heap);

	duk_push_bare_object(thr);

	/* [ <nargs> target base key {} ] */

	/* We only push a wrapped error, replacing the call target (at
	 * idx_func) with the error to ensure side effects come out
	 * correctly:
	 * - Property read
	 * - Call argument evaluation
	 * - Callability check and error thrown
	 *
	 * A hidden Symbol on the wrapper object pushed above is used by
	 * call handling to figure out the error is to be thrown as is.
	 * It is CRITICAL that the hidden Symbol can never occur on a
	 * user visible object that may get thrown.
	 */

#if defined(DUK_USE_PARANOID_ERRORS)
	str_targ = duk_get_type_name(thr, -4);
	str_key = duk_get_type_name(thr, -2);
	str_base = duk_get_type_name(thr, -3);
	duk_push_error_object(thr,
	                      DUK_ERR_TYPE_ERROR | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
	                      "%s not callable (property %s of %s)", str_targ, str_key, str_base);
	duk_xdef_prop_stridx(thr, -2, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE);  /* Marker property, reuse _Target. */
	/* [ <nargs> target base key { _Target: error } ] */
	duk_replace(thr, entry_top - 1);
#else
	str_targ = duk_push_string_readable(thr, -4);
	str_key = duk_push_string_readable(thr, -3);
	str_base = duk_push_string_readable(thr, -5);
	duk_push_error_object(thr,
	                      DUK_ERR_TYPE_ERROR | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
	                      "%s not callable (property %s of %s)", str_targ, str_key, str_base);
	/* [ <nargs> target base key {} str_targ str_key str_base error ] */
	duk_xdef_prop_stridx(thr, -5, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE);  /* Marker property, reuse _Target. */
	/* [ <nargs> target base key { _Target: error } str_targ str_key str_base ] */
	duk_swap(thr, -4, entry_top - 1);
	/* [ <nargs> { _Target: error } base key target str_targ str_key str_base ] */
#endif

	/* [ <nregs> { _Target: error } <variable> */
	duk_set_top(thr, entry_top);

	/* [ <nregs> { _Target: error } */
	DUK_ASSERT(!duk_is_callable(thr, -1));  /* Critical so that call handling will throw the error. */
}
#endif  /* DUK_USE_VERBOSE_ERRORS */

/* automatic undefs */
#undef DUK__AUGMENT_CALL_RELAX_COUNT
#undef DUK__CALL_HANDLING_REQUIRE_STACK
/*
 *  ECMAScript compiler.
 *
 *  Parses an input string and generates a function template result.
 *  Compilation may happen in multiple contexts (global code, eval
 *  code, function code).
 *
 *  The parser uses a traditional top-down recursive parsing for the
 *  statement level, and an operator precedence based top-down approach
 *  for the expression level.  The attempt is to minimize the C stack
 *  depth.  Bytecode is generated directly without an intermediate
 *  representation (tree), at the cost of needing two (and sometimes
 *  three) passes over each function.
 *
 *  The top-down recursive parser functions are named "duk__parse_XXX".
 *
 *  Recursion limits are in key functions to prevent arbitrary C recursion:
 *  function body parsing, statement parsing, and expression parsing.
 *
 *  See doc/compiler.rst for discussion on the design.
 *
 *  A few typing notes:
 *
 *    - duk_regconst_t: signed, highest bit set (< 0) means constant,
 *      some call sites use -1 for "none" (equivalent to constant 0x7fffffff)
 *    - PC values: duk_int_t, negative values used as markers
 */

/* #include duk_internal.h -> already included */

/* If highest bit of a register number is set, it refers to a constant instead.
 * When interpreted as a signed value, this means const values are always
 * negative (when interpreted as two's complement).  For example DUK__ISREG_TEMP()
 * uses this approach to avoid an explicit DUK__ISREG() check (the condition is
 * logically "'x' is a register AND 'x' >= temp_first").
 */
#define DUK__CONST_MARKER                   DUK_REGCONST_CONST_MARKER
#define DUK__REMOVECONST(x)                 ((x) & ~DUK__CONST_MARKER)
#define DUK__ISREG(x)                       ((x) >= 0)
#define DUK__ISCONST(x)                     ((x) < 0)
#define DUK__ISREG_TEMP(comp_ctx,x)         ((duk_int32_t) (x) >= (duk_int32_t) ((comp_ctx)->curr_func.temp_first))   /* Check for x >= temp_first && x >= 0 by comparing as signed. */
#define DUK__ISREG_NOTTEMP(comp_ctx,x)      ((duk_uint32_t) (x) < (duk_uint32_t) ((comp_ctx)->curr_func.temp_first))  /* Check for x >= 0 && x < temp_first by interpreting as unsigned. */
#define DUK__GETTEMP(comp_ctx)              ((comp_ctx)->curr_func.temp_next)
#define DUK__SETTEMP(comp_ctx,x)            ((comp_ctx)->curr_func.temp_next = (x))  /* dangerous: must only lower (temp_max not updated) */
#define DUK__SETTEMP_CHECKMAX(comp_ctx,x)   duk__settemp_checkmax((comp_ctx),(x))
#define DUK__ALLOCTEMP(comp_ctx)            duk__alloctemp((comp_ctx))
#define DUK__ALLOCTEMPS(comp_ctx,count)     duk__alloctemps((comp_ctx),(count))

/* Init value set size for array and object literals. */
#define DUK__MAX_ARRAY_INIT_VALUES        20
#define DUK__MAX_OBJECT_INIT_PAIRS        10

/* XXX: hack, remove when const lookup is not O(n) */
#define DUK__GETCONST_MAX_CONSTS_CHECK    256

/* These limits are based on bytecode limits.  Max temps is limited
 * by duk_hcompfunc nargs/nregs fields being 16 bits.
 */
#define DUK__MAX_CONSTS                   DUK_BC_BC_MAX
#define DUK__MAX_FUNCS                    DUK_BC_BC_MAX
#define DUK__MAX_TEMPS                    0xffffL

/* Initial bytecode size allocation. */
#if defined(DUK_USE_PREFER_SIZE)
#define DUK__BC_INITIAL_INSTS             16
#else
#define DUK__BC_INITIAL_INSTS             256
#endif

#define DUK__RECURSION_INCREASE(comp_ctx,thr)  do { \
		DUK_DDD(DUK_DDDPRINT("RECURSION INCREASE: %s:%ld", (const char *) DUK_FILE_MACRO, (long) DUK_LINE_MACRO)); \
		duk__comp_recursion_increase((comp_ctx)); \
	} while (0)

#define DUK__RECURSION_DECREASE(comp_ctx,thr)  do { \
		DUK_DDD(DUK_DDDPRINT("RECURSION DECREASE: %s:%ld", (const char *) DUK_FILE_MACRO, (long) DUK_LINE_MACRO)); \
		duk__comp_recursion_decrease((comp_ctx)); \
	} while (0)

/* Value stack slot limits: these are quite approximate right now, and
 * because they overlap in control flow, some could be eliminated.
 */
#define DUK__COMPILE_ENTRY_SLOTS          8
#define DUK__FUNCTION_INIT_REQUIRE_SLOTS  16
#define DUK__FUNCTION_BODY_REQUIRE_SLOTS  16
#define DUK__PARSE_STATEMENTS_SLOTS       16
#define DUK__PARSE_EXPR_SLOTS             16

/* Temporary structure used to pass a stack allocated region through
 * duk_safe_call().
 */
typedef struct {
	duk_small_uint_t flags;
	duk_compiler_ctx comp_ctx_alloc;
	duk_lexer_point lex_pt_alloc;
} duk__compiler_stkstate;

/*
 *  Prototypes
 */

/* lexing */
DUK_LOCAL_DECL void duk__advance_helper(duk_compiler_ctx *comp_ctx, duk_small_int_t expect);
DUK_LOCAL_DECL void duk__advance_expect(duk_compiler_ctx *comp_ctx, duk_small_int_t expect);
DUK_LOCAL_DECL void duk__advance(duk_compiler_ctx *ctx);

/* function helpers */
DUK_LOCAL_DECL void duk__init_func_valstack_slots(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__reset_func_for_pass2(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__init_varmap_and_prologue_for_pass2(duk_compiler_ctx *comp_ctx, duk_regconst_t *out_stmt_value_reg);
DUK_LOCAL_DECL void duk__convert_to_func_template(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_int_t duk__cleanup_varmap(duk_compiler_ctx *comp_ctx);

/* code emission */
DUK_LOCAL_DECL duk_int_t duk__get_current_pc(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_compiler_instr *duk__get_instr_ptr(duk_compiler_ctx *comp_ctx, duk_int_t pc);
DUK_LOCAL_DECL void duk__emit(duk_compiler_ctx *comp_ctx, duk_instr_t ins);
DUK_LOCAL_DECL void duk__emit_op_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t op);
DUK_LOCAL_DECL void duk__emit_a_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b, duk_regconst_t c);
DUK_LOCAL_DECL void duk__emit_a_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b);
DUK_LOCAL_DECL void duk__emit_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t b, duk_regconst_t c);
#if 0  /* unused */
DUK_LOCAL_DECL void duk__emit_a(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a);
DUK_LOCAL_DECL void duk__emit_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t b);
#endif
DUK_LOCAL_DECL void duk__emit_a_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t bc);
DUK_LOCAL_DECL void duk__emit_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t bc);
DUK_LOCAL_DECL void duk__emit_abc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t abc);
DUK_LOCAL_DECL void duk__emit_load_int32(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val);
DUK_LOCAL_DECL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val);
DUK_LOCAL_DECL void duk__emit_jump(duk_compiler_ctx *comp_ctx, duk_int_t target_pc);
DUK_LOCAL_DECL duk_int_t duk__emit_jump_empty(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__insert_jump_entry(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc);
DUK_LOCAL_DECL void duk__patch_jump(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc, duk_int_t target_pc);
DUK_LOCAL_DECL void duk__patch_jump_here(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc);
DUK_LOCAL_DECL void duk__patch_trycatch(duk_compiler_ctx *comp_ctx, duk_int_t ldconst_pc, duk_int_t trycatch_pc, duk_regconst_t reg_catch, duk_regconst_t const_varname, duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__emit_if_false_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst);
DUK_LOCAL_DECL void duk__emit_if_true_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst);
DUK_LOCAL_DECL void duk__emit_invalid(duk_compiler_ctx *comp_ctx);

/* ivalue/ispec helpers */
DUK_LOCAL_DECL void duk__ivalue_regconst(duk_ivalue *x, duk_regconst_t regconst);
DUK_LOCAL_DECL void duk__ivalue_plain_fromstack(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL void duk__ivalue_var_fromstack(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL void duk__ivalue_var_hstring(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_hstring *h);
DUK_LOCAL_DECL void duk__copy_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *src, duk_ispec *dst);
DUK_LOCAL_DECL void duk__copy_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *src, duk_ivalue *dst);
DUK_LOCAL_DECL duk_regconst_t duk__alloctemps(duk_compiler_ctx *comp_ctx, duk_small_int_t num);
DUK_LOCAL_DECL duk_regconst_t duk__alloctemp(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__settemp_checkmax(duk_compiler_ctx *comp_ctx, duk_regconst_t temp_next);
DUK_LOCAL_DECL duk_regconst_t duk__getconst(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL
duk_regconst_t duk__ispec_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                         duk_ispec *x,
                                         duk_regconst_t forced_reg,
                                         duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__ispec_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ispec *x, duk_regconst_t forced_reg);
DUK_LOCAL_DECL void duk__ivalue_toplain_raw(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_regconst_t forced_reg);
DUK_LOCAL_DECL void duk__ivalue_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL void duk__ivalue_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL
duk_regconst_t duk__ivalue_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                          duk_ivalue *x,
                                          duk_regconst_t forced_reg,
                                          duk_small_uint_t flags);
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
#endif
DUK_LOCAL_DECL void duk__ivalue_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_int_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x);

/* identifier handling */
DUK_LOCAL_DECL duk_regconst_t duk__lookup_active_register_binding(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_bool_t duk__lookup_lhs(duk_compiler_ctx *ctx, duk_regconst_t *out_reg_varbind, duk_regconst_t *out_rc_varname);

/* label handling */
DUK_LOCAL_DECL void duk__add_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_int_t pc_label, duk_int_t label_id);
DUK_LOCAL_DECL void duk__update_label_flags(duk_compiler_ctx *comp_ctx, duk_int_t label_id, duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__lookup_active_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_bool_t is_break, duk_int_t *out_label_id, duk_int_t *out_label_catch_depth, duk_int_t *out_label_pc, duk_bool_t *out_is_closest);
DUK_LOCAL_DECL void duk__reset_labels_to_length(duk_compiler_ctx *comp_ctx, duk_size_t len);

/* top-down expression parser */
DUK_LOCAL_DECL void duk__expr_nud(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__expr_led(duk_compiler_ctx *comp_ctx, duk_ivalue *left, duk_ivalue *res);
DUK_LOCAL_DECL duk_small_uint_t duk__expr_lbp(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_bool_t duk__expr_is_empty(duk_compiler_ctx *comp_ctx);

/* exprtop is the top level variant which resets nud/led counts */
DUK_LOCAL_DECL void duk__expr(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL void duk__exprtop(duk_compiler_ctx *ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);

/* convenience helpers */
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__expr_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__expr_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__expr_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_regconst_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__expr_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__expr_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__expr_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL void duk__expr_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL duk_regconst_t duk__exprtop_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__exprtop_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__exprtop_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_regconst_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__exprtop_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL void duk__exprtop_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif

/* expression parsing helpers */
DUK_LOCAL_DECL duk_int_t duk__parse_arguments(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__nud_array_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__nud_object_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res);

/* statement parsing */
DUK_LOCAL_DECL void duk__parse_var_decl(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags, duk_regconst_t *out_reg_varbind, duk_regconst_t *out_rc_varname);
DUK_LOCAL_DECL void duk__parse_var_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags);
DUK_LOCAL_DECL void duk__parse_for_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_switch_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_if_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_do_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_while_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_break_or_continue_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_return_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_throw_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_try_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_with_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_bool_t allow_source_elem);
DUK_LOCAL_DECL duk_int_t duk__stmt_label_site(duk_compiler_ctx *comp_ctx, duk_int_t label_id);
DUK_LOCAL_DECL void duk__parse_stmts(duk_compiler_ctx *comp_ctx, duk_bool_t allow_source_elem, duk_bool_t expect_eof, duk_bool_t regexp_after);

DUK_LOCAL_DECL void duk__parse_func_body(duk_compiler_ctx *comp_ctx, duk_bool_t expect_eof, duk_bool_t implicit_return_value, duk_bool_t regexp_after, duk_small_int_t expect_token);
DUK_LOCAL_DECL void duk__parse_func_formals(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__parse_func_like_raw(duk_compiler_ctx *comp_ctx, duk_small_uint_t flags);
DUK_LOCAL_DECL duk_int_t duk__parse_func_like_fnum(duk_compiler_ctx *comp_ctx, duk_small_uint_t flags);

#define DUK__FUNC_FLAG_DECL            (1 << 0)   /* Parsing a function declaration. */
#define DUK__FUNC_FLAG_GETSET          (1 << 1)   /* Parsing an object literal getter/setter. */
#define DUK__FUNC_FLAG_METDEF          (1 << 2)   /* Parsing an object literal method definition shorthand. */
#define DUK__FUNC_FLAG_PUSHNAME_PASS1  (1 << 3)   /* Push function name when creating template (first pass only). */
#define DUK__FUNC_FLAG_USE_PREVTOKEN   (1 << 4)   /* Use prev_token to start function parsing (workaround for object literal). */

/*
 *  Parser control values for tokens.  The token table is ordered by the
 *  DUK_TOK_XXX defines.
 *
 *  The binding powers are for lbp() use (i.e. for use in led() context).
 *  Binding powers are positive for typing convenience, and bits at the
 *  top should be reserved for flags.  Binding power step must be higher
 *  than 1 so that binding power "lbp - 1" can be used for right associative
 *  operators.  Currently a step of 2 is used (which frees one more bit for
 *  flags).
 */

/* XXX: actually single step levels would work just fine, clean up */

/* binding power "levels" (see doc/compiler.rst) */
#define DUK__BP_INVALID                0             /* always terminates led() */
#define DUK__BP_EOF                    2
#define DUK__BP_CLOSING                4             /* token closes expression, e.g. ')', ']' */
#define DUK__BP_FOR_EXPR               DUK__BP_CLOSING    /* bp to use when parsing a top level Expression */
#define DUK__BP_COMMA                  6
#define DUK__BP_ASSIGNMENT             8
#define DUK__BP_CONDITIONAL            10
#define DUK__BP_LOR                    12
#define DUK__BP_LAND                   14
#define DUK__BP_BOR                    16
#define DUK__BP_BXOR                   18
#define DUK__BP_BAND                   20
#define DUK__BP_EQUALITY               22
#define DUK__BP_RELATIONAL             24
#define DUK__BP_SHIFT                  26
#define DUK__BP_ADDITIVE               28
#define DUK__BP_MULTIPLICATIVE         30
#define DUK__BP_EXPONENTIATION         32
#define DUK__BP_POSTFIX                34
#define DUK__BP_CALL                   36
#define DUK__BP_MEMBER                 38

#define DUK__TOKEN_LBP_BP_MASK         0x1f
#define DUK__TOKEN_LBP_FLAG_NO_REGEXP  (1 << 5)   /* regexp literal must not follow this token */
#define DUK__TOKEN_LBP_FLAG_TERMINATES (1 << 6)   /* terminates expression; e.g. post-increment/-decrement */
#define DUK__TOKEN_LBP_FLAG_UNUSED     (1 << 7)   /* unused */

#define DUK__TOKEN_LBP_GET_BP(x)       ((duk_small_uint_t) (((x) & DUK__TOKEN_LBP_BP_MASK) * 2))

#define DUK__MK_LBP(bp)                ((bp) >> 1)    /* bp is assumed to be even */
#define DUK__MK_LBP_FLAGS(bp,flags)    (((bp) >> 1) | (flags))

DUK_LOCAL const duk_uint8_t duk__token_lbp[] = {
	DUK__MK_LBP(DUK__BP_EOF),                                 /* DUK_TOK_EOF */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_IDENTIFIER */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_BREAK */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CASE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CATCH */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CONTINUE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DEBUGGER */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DEFAULT */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DELETE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DO */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_ELSE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FINALLY */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FOR */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FUNCTION */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IF */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_IN */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_INSTANCEOF */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_NEW */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_RETURN */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SWITCH */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_THIS */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_THROW */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_TRY */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_TYPEOF */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_VAR */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CONST */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_VOID */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_WHILE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_WITH */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CLASS */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_ENUM */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_EXPORT */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_EXTENDS */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IMPORT */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SUPER */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_NULL */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_TRUE */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_FALSE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_GET */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SET */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IMPLEMENTS */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_INTERFACE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LET */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PACKAGE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PRIVATE */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PROTECTED */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PUBLIC */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_STATIC */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_YIELD */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LCURLY */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RCURLY */
	DUK__MK_LBP(DUK__BP_MEMBER),                              /* DUK_TOK_LBRACKET */
	DUK__MK_LBP_FLAGS(DUK__BP_CLOSING, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RBRACKET */
	DUK__MK_LBP(DUK__BP_CALL),                                /* DUK_TOK_LPAREN */
	DUK__MK_LBP_FLAGS(DUK__BP_CLOSING, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RPAREN */
	DUK__MK_LBP(DUK__BP_MEMBER),                              /* DUK_TOK_PERIOD */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SEMICOLON */
	DUK__MK_LBP(DUK__BP_COMMA),                               /* DUK_TOK_COMMA */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_LT */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_GT */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_LE */
	DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_GE */
	DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_EQ */
	DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_NEQ */
	DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_SEQ */
	DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_SNEQ */
	DUK__MK_LBP(DUK__BP_ADDITIVE),                            /* DUK_TOK_ADD */
	DUK__MK_LBP(DUK__BP_ADDITIVE),                            /* DUK_TOK_SUB */
	DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_MUL */
	DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_DIV */
	DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_MOD */
	DUK__MK_LBP(DUK__BP_EXPONENTIATION),                      /* DUK_TOK_EXP */
	DUK__MK_LBP_FLAGS(DUK__BP_POSTFIX, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_INCREMENT */
	DUK__MK_LBP_FLAGS(DUK__BP_POSTFIX, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_DECREMENT */
	DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_ALSHIFT */
	DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_ARSHIFT */
	DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_RSHIFT */
	DUK__MK_LBP(DUK__BP_BAND),                                /* DUK_TOK_BAND */
	DUK__MK_LBP(DUK__BP_BOR),                                 /* DUK_TOK_BOR */
	DUK__MK_LBP(DUK__BP_BXOR),                                /* DUK_TOK_BXOR */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LNOT */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_BNOT */
	DUK__MK_LBP(DUK__BP_LAND),                                /* DUK_TOK_LAND */
	DUK__MK_LBP(DUK__BP_LOR),                                 /* DUK_TOK_LOR */
	DUK__MK_LBP(DUK__BP_CONDITIONAL),                         /* DUK_TOK_QUESTION */
	DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_COLON */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_EQUALSIGN */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ADD_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_SUB_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_MUL_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_DIV_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_MOD_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_EXP_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ALSHIFT_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ARSHIFT_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_RSHIFT_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BAND_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BOR_EQ */
	DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BXOR_EQ */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_NUMBER */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_STRING */
	DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_REGEXP */
};

/*
 *  Misc helpers
 */

DUK_LOCAL void duk__comp_recursion_increase(duk_compiler_ctx *comp_ctx) {
	DUK_ASSERT(comp_ctx != NULL);
	DUK_ASSERT(comp_ctx->recursion_depth >= 0);
	if (comp_ctx->recursion_depth >= comp_ctx->recursion_limit) {
		DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_COMPILER_RECURSION_LIMIT);
		DUK_WO_NORETURN(return;);
	}
	comp_ctx->recursion_depth++;
}

DUK_LOCAL void duk__comp_recursion_decrease(duk_compiler_ctx *comp_ctx) {
	DUK_ASSERT(comp_ctx != NULL);
	DUK_ASSERT(comp_ctx->recursion_depth > 0);
	comp_ctx->recursion_depth--;
}

DUK_LOCAL duk_bool_t duk__hstring_is_eval_or_arguments(duk_compiler_ctx *comp_ctx, duk_hstring *h) {
	DUK_UNREF(comp_ctx);
	DUK_ASSERT(h != NULL);
	return DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(h);
}

DUK_LOCAL duk_bool_t duk__hstring_is_eval_or_arguments_in_strict_mode(duk_compiler_ctx *comp_ctx, duk_hstring *h) {
	DUK_ASSERT(h != NULL);
	return (comp_ctx->curr_func.is_strict &&
	        DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(h));
}

/*
 *  Parser duk__advance() token eating functions
 */

/* XXX: valstack handling is awkward.  Add a valstack helper which
 * avoids dup():ing; valstack_copy(src, dst)?
 */

DUK_LOCAL void duk__advance_helper(duk_compiler_ctx *comp_ctx, duk_small_int_t expect) {
	duk_hthread *thr = comp_ctx->thr;
	duk_bool_t regexp;

	DUK_ASSERT_DISABLE(comp_ctx->curr_token.t >= 0);  /* unsigned */
	DUK_ASSERT(comp_ctx->curr_token.t <= DUK_TOK_MAXVAL);  /* MAXVAL is inclusive */

	/*
	 *  Use current token to decide whether a RegExp can follow.
	 *
	 *  We can use either 't' or 't_nores'; the latter would not
	 *  recognize keywords.  Some keywords can be followed by a
	 *  RegExp (e.g. "return"), so using 't' is better.  This is
	 *  not trivial, see doc/compiler.rst.
	 */

	regexp = 1;
	if (duk__token_lbp[comp_ctx->curr_token.t] & DUK__TOKEN_LBP_FLAG_NO_REGEXP) {
		regexp = 0;
	}
	if (comp_ctx->curr_func.reject_regexp_in_adv) {
		comp_ctx->curr_func.reject_regexp_in_adv = 0;
		regexp = 0;
	}
	if (comp_ctx->curr_func.allow_regexp_in_adv) {
		comp_ctx->curr_func.allow_regexp_in_adv = 0;
		regexp = 1;
	}

	if (expect >= 0 && comp_ctx->curr_token.t != (duk_small_uint_t) expect) {
		DUK_D(DUK_DPRINT("parse error: expect=%ld, got=%ld",
		                 (long) expect, (long) comp_ctx->curr_token.t));
		DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
		DUK_WO_NORETURN(return;);
	}

	/* make current token the previous; need to fiddle with valstack "backing store" */
	duk_memcpy(&comp_ctx->prev_token, &comp_ctx->curr_token, sizeof(duk_token));
	duk_copy(thr, comp_ctx->tok11_idx, comp_ctx->tok21_idx);
	duk_copy(thr, comp_ctx->tok12_idx, comp_ctx->tok22_idx);

	/* parse new token */
	duk_lexer_parse_js_input_element(&comp_ctx->lex,
	                                 &comp_ctx->curr_token,
	                                 comp_ctx->curr_func.is_strict,
	                                 regexp);

	DUK_DDD(DUK_DDDPRINT("advance: curr: tok=%ld/%ld,%ld,term=%ld,%!T,%!T "
	                     "prev: tok=%ld/%ld,%ld,term=%ld,%!T,%!T",
	                     (long) comp_ctx->curr_token.t,
	                     (long) comp_ctx->curr_token.t_nores,
	                     (long) comp_ctx->curr_token.start_line,
	                     (long) comp_ctx->curr_token.lineterm,
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->tok11_idx),
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->tok12_idx),
	                     (long) comp_ctx->prev_token.t,
	                     (long) comp_ctx->prev_token.t_nores,
	                     (long) comp_ctx->prev_token.start_line,
	                     (long) comp_ctx->prev_token.lineterm,
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->tok21_idx),
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->tok22_idx)));
}

/* advance, expecting current token to be a specific token; parse next token in regexp context */
DUK_LOCAL void duk__advance_expect(duk_compiler_ctx *comp_ctx, duk_small_int_t expect) {
	duk__advance_helper(comp_ctx, expect);
}

/* advance, whatever the current token is; parse next token in regexp context */
DUK_LOCAL void duk__advance(duk_compiler_ctx *comp_ctx) {
	duk__advance_helper(comp_ctx, -1);
}

/*
 *  Helpers for duk_compiler_func.
 */

/* init function state: inits valstack allocations */
DUK_LOCAL void duk__init_func_valstack_slots(duk_compiler_ctx *comp_ctx) {
	duk_compiler_func *func = &comp_ctx->curr_func;
	duk_hthread *thr = comp_ctx->thr;
	duk_idx_t entry_top;

	entry_top = duk_get_top(thr);

	duk_memzero(func, sizeof(*func));  /* intentional overlap with earlier memzero */
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	func->h_name = NULL;
	func->h_consts = NULL;
	func->h_funcs = NULL;
	func->h_decls = NULL;
	func->h_labelnames = NULL;
	func->h_labelinfos = NULL;
	func->h_argnames = NULL;
	func->h_varmap = NULL;
#endif

	duk_require_stack(thr, DUK__FUNCTION_INIT_REQUIRE_SLOTS);

	DUK_BW_INIT_PUSHBUF(thr, &func->bw_code, DUK__BC_INITIAL_INSTS * sizeof(duk_compiler_instr));
	/* code_idx = entry_top + 0 */

	duk_push_bare_array(thr);
	func->consts_idx = entry_top + 1;
	func->h_consts = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 1);
	DUK_ASSERT(func->h_consts != NULL);

	duk_push_bare_array(thr);
	func->funcs_idx = entry_top + 2;
	func->h_funcs = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 2);
	DUK_ASSERT(func->h_funcs != NULL);
	DUK_ASSERT(func->fnum_next == 0);

	duk_push_bare_array(thr);
	func->decls_idx = entry_top + 3;
	func->h_decls = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 3);
	DUK_ASSERT(func->h_decls != NULL);

	duk_push_bare_array(thr);
	func->labelnames_idx = entry_top + 4;
	func->h_labelnames = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 4);
	DUK_ASSERT(func->h_labelnames != NULL);

	duk_push_dynamic_buffer(thr, 0);
	func->labelinfos_idx = entry_top + 5;
	func->h_labelinfos = (duk_hbuffer_dynamic *) duk_known_hbuffer(thr, entry_top + 5);
	DUK_ASSERT(func->h_labelinfos != NULL);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(func->h_labelinfos) && !DUK_HBUFFER_HAS_EXTERNAL(func->h_labelinfos));

	duk_push_bare_array(thr);
	func->argnames_idx = entry_top + 6;
	func->h_argnames = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 6);
	DUK_ASSERT(func->h_argnames != NULL);

	duk_push_bare_object(thr);
	func->varmap_idx = entry_top + 7;
	func->h_varmap = DUK_GET_HOBJECT_POSIDX(thr, entry_top + 7);
	DUK_ASSERT(func->h_varmap != NULL);
}

/* reset function state (prepare for pass 2) */
DUK_LOCAL void duk__reset_func_for_pass2(duk_compiler_ctx *comp_ctx) {
	duk_compiler_func *func = &comp_ctx->curr_func;
	duk_hthread *thr = comp_ctx->thr;

	/* reset bytecode buffer but keep current size; pass 2 will
	 * require same amount or more.
	 */
	DUK_BW_RESET_SIZE(thr, &func->bw_code);

	duk_set_length(thr, func->consts_idx, 0);
	/* keep func->h_funcs; inner functions are not reparsed to avoid O(depth^2) parsing */
	func->fnum_next = 0;
	/* duk_set_length(thr, func->funcs_idx, 0); */
	duk_set_length(thr, func->labelnames_idx, 0);
	duk_hbuffer_reset(thr, func->h_labelinfos);
	/* keep func->h_argnames; it is fixed for all passes */

	/* truncated in case pass 3 needed */
	duk_push_bare_object(thr);
	duk_replace(thr, func->varmap_idx);
	func->h_varmap = DUK_GET_HOBJECT_POSIDX(thr, func->varmap_idx);
	DUK_ASSERT(func->h_varmap != NULL);
}

/* cleanup varmap from any null entries, compact it, etc; returns number
 * of final entries after cleanup.
 */
DUK_LOCAL duk_int_t duk__cleanup_varmap(duk_compiler_ctx *comp_ctx) {
	duk_hthread *thr = comp_ctx->thr;
	duk_hobject *h_varmap;
	duk_hstring *h_key;
	duk_tval *tv;
	duk_uint32_t i, e_next;
	duk_int_t ret;

	/* [ ... varmap ] */

	h_varmap = DUK_GET_HOBJECT_NEGIDX(thr, -1);
	DUK_ASSERT(h_varmap != NULL);

	ret = 0;
	e_next = DUK_HOBJECT_GET_ENEXT(h_varmap);
	for (i = 0; i < e_next; i++) {
		h_key = DUK_HOBJECT_E_GET_KEY(thr->heap, h_varmap, i);
		if (!h_key) {
			continue;
		}

		DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h_varmap, i));

		/* The entries can either be register numbers or 'null' values.
		 * Thus, no need to DECREF them and get side effects.  DECREF'ing
		 * the keys (strings) can cause memory to be freed but no side
		 * effects as strings don't have finalizers.  This is why we can
		 * rely on the object properties not changing from underneath us.
		 */

		tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h_varmap, i);
		if (!DUK_TVAL_IS_NUMBER(tv)) {
			DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv));
			DUK_HOBJECT_E_SET_KEY(thr->heap, h_varmap, i, NULL);
			DUK_HSTRING_DECREF(thr, h_key);
			/* when key is NULL, value is garbage so no need to set */
		} else {
			ret++;
		}
	}

	duk_compact_m1(thr);

	return ret;
}

/* Convert duk_compiler_func into a function template, leaving the result
 * on top of stack.
 */
/* XXX: awkward and bloated asm -- use faster internal accesses */
DUK_LOCAL void duk__convert_to_func_template(duk_compiler_ctx *comp_ctx) {
	duk_compiler_func *func = &comp_ctx->curr_func;
	duk_hthread *thr = comp_ctx->thr;
	duk_hcompfunc *h_res;
	duk_hbuffer_fixed *h_data;
	duk_size_t consts_count;
	duk_size_t funcs_count;
	duk_size_t code_count;
	duk_size_t code_size;
	duk_size_t data_size;
	duk_size_t i;
	duk_tval *p_const;
	duk_hobject **p_func;
	duk_instr_t *p_instr;
	duk_compiler_instr *q_instr;
	duk_tval *tv;
	duk_bool_t keep_varmap;
	duk_bool_t keep_formals;
#if !defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_size_t formals_length;
#endif

	DUK_DDD(DUK_DDDPRINT("converting duk_compiler_func to function/template"));

	/*
	 *  Push result object and init its flags
	 */

	/* Valstack should suffice here, required on function valstack init */

	h_res = duk_push_hcompfunc(thr);
	DUK_ASSERT(h_res != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) h_res) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, (duk_hobject *) h_res, NULL);  /* Function templates are "bare objects". */

	if (func->is_function) {
		DUK_DDD(DUK_DDDPRINT("function -> set NEWENV"));
		DUK_HOBJECT_SET_NEWENV((duk_hobject *) h_res);

		if (!func->is_arguments_shadowed) {
			/* arguments object would be accessible; note that shadowing
			 * bindings are arguments or function declarations, neither
			 * of which are deletable, so this is safe.
			 */

			if (func->id_access_arguments || func->may_direct_eval) {
				DUK_DDD(DUK_DDDPRINT("function may access 'arguments' object directly or "
				                     "indirectly -> set CREATEARGS"));
				DUK_HOBJECT_SET_CREATEARGS((duk_hobject *) h_res);
			}
		}
	} else if (func->is_eval && func->is_strict) {
		DUK_DDD(DUK_DDDPRINT("strict eval code -> set NEWENV"));
		DUK_HOBJECT_SET_NEWENV((duk_hobject *) h_res);
	} else {
		/* non-strict eval: env is caller's env or global env (direct vs. indirect call)
		 * global code: env is is global env
		 */
		DUK_DDD(DUK_DDDPRINT("non-strict eval code or global code -> no NEWENV"));
		DUK_ASSERT(!DUK_HOBJECT_HAS_NEWENV((duk_hobject *) h_res));
	}

#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	if (func->is_function && func->is_namebinding && func->h_name != NULL) {
		/* Object literal set/get functions have a name (property
		 * name) but must not have a lexical name binding, see
		 * test-bug-getset-func-name.js.
		 */
		DUK_DDD(DUK_DDDPRINT("function expression with a name -> set NAMEBINDING"));
		DUK_HOBJECT_SET_NAMEBINDING((duk_hobject *) h_res);
	}
#endif

	if (func->is_strict) {
		DUK_DDD(DUK_DDDPRINT("function is strict -> set STRICT"));
		DUK_HOBJECT_SET_STRICT((duk_hobject *) h_res);
	}

	if (func->is_notail) {
		DUK_DDD(DUK_DDDPRINT("function is notail -> set NOTAIL"));
		DUK_HOBJECT_SET_NOTAIL((duk_hobject *) h_res);
	}

	if (func->is_constructable) {
		DUK_DDD(DUK_DDDPRINT("function is constructable -> set CONSTRUCTABLE"));
		DUK_HOBJECT_SET_CONSTRUCTABLE((duk_hobject *) h_res);
	}

	/*
	 *  Build function fixed size 'data' buffer, which contains bytecode,
	 *  constants, and inner function references.
	 *
	 *  During the building phase 'data' is reachable but incomplete.
	 *  Only incref's occur during building (no refzero or GC happens),
	 *  so the building process is atomic.
	 */

	consts_count = duk_hobject_get_length(thr, func->h_consts);
	funcs_count = duk_hobject_get_length(thr, func->h_funcs) / 3;
	code_count = DUK_BW_GET_SIZE(thr, &func->bw_code) / sizeof(duk_compiler_instr);
	code_size = code_count * sizeof(duk_instr_t);

	data_size = consts_count * sizeof(duk_tval) +
	            funcs_count * sizeof(duk_hobject *) +
	            code_size;

	DUK_DDD(DUK_DDDPRINT("consts_count=%ld, funcs_count=%ld, code_size=%ld -> "
	                     "data_size=%ld*%ld + %ld*%ld + %ld = %ld",
	                     (long) consts_count, (long) funcs_count, (long) code_size,
	                     (long) consts_count, (long) sizeof(duk_tval),
	                     (long) funcs_count, (long) sizeof(duk_hobject *),
	                     (long) code_size, (long) data_size));

	duk_push_fixed_buffer_nozero(thr, data_size);
	h_data = (duk_hbuffer_fixed *) (void *) duk_known_hbuffer(thr, -1);

	DUK_HCOMPFUNC_SET_DATA(thr->heap, h_res, (duk_hbuffer *) h_data);
	DUK_HEAPHDR_INCREF(thr, h_data);

	p_const = (duk_tval *) (void *) DUK_HBUFFER_FIXED_GET_DATA_PTR(thr->heap, h_data);
	for (i = 0; i < consts_count; i++) {
		DUK_ASSERT(i <= DUK_UARRIDX_MAX);  /* const limits */
		tv = duk_hobject_find_array_entry_tval_ptr(thr->heap, func->h_consts, (duk_uarridx_t) i);
		DUK_ASSERT(tv != NULL);
		DUK_TVAL_SET_TVAL(p_const, tv);
		p_const++;
		DUK_TVAL_INCREF(thr, tv);  /* may be a string constant */

		DUK_DDD(DUK_DDDPRINT("constant: %!T", (duk_tval *) tv));
	}

	p_func = (duk_hobject **) p_const;
	DUK_HCOMPFUNC_SET_FUNCS(thr->heap, h_res, p_func);
	for (i = 0; i < funcs_count; i++) {
		duk_hobject *h;
		DUK_ASSERT(i * 3 <= DUK_UARRIDX_MAX);  /* func limits */
		tv = duk_hobject_find_array_entry_tval_ptr(thr->heap, func->h_funcs, (duk_uarridx_t) (i * 3));
		DUK_ASSERT(tv != NULL);
		DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(h));
		*p_func++ = h;
		DUK_HOBJECT_INCREF(thr, h);

		DUK_DDD(DUK_DDDPRINT("inner function: %p -> %!iO",
		                     (void *) h, (duk_heaphdr *) h));
	}

	p_instr = (duk_instr_t *) p_func;
	DUK_HCOMPFUNC_SET_BYTECODE(thr->heap, h_res, p_instr);

	/* copy bytecode instructions one at a time */
	q_instr = (duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(thr, &func->bw_code);
	for (i = 0; i < code_count; i++) {
		p_instr[i] = q_instr[i].ins;
	}
	/* Note: 'q_instr' is still used below */

	DUK_ASSERT((duk_uint8_t *) (p_instr + code_count) == DUK_HBUFFER_FIXED_GET_DATA_PTR(thr->heap, h_data) + data_size);

	duk_pop(thr);  /* 'data' (and everything in it) is reachable through h_res now */

	/*
	 *  Init non-property result fields
	 *
	 *  'nregs' controls how large a register frame is allocated.
	 *
	 *  'nargs' controls how many formal arguments are written to registers:
	 *  r0, ... r(nargs-1).  The remaining registers are initialized to
	 *  undefined.
	 */

	DUK_ASSERT(func->temp_max >= 0);
	h_res->nregs = (duk_uint16_t) func->temp_max;
	h_res->nargs = (duk_uint16_t) duk_hobject_get_length(thr, func->h_argnames);
	DUK_ASSERT(h_res->nregs >= h_res->nargs);  /* pass2 allocation handles this */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	h_res->start_line = (duk_uint32_t) func->min_line;
	h_res->end_line = (duk_uint32_t) func->max_line;
#endif

	/*
	 *  Init object properties
	 *
	 *  Properties should be added in decreasing order of access frequency.
	 *  (Not very critical for function templates.)
	 */

	DUK_DDD(DUK_DDDPRINT("init function properties"));

	/* [ ... res ] */

	/* _Varmap: omitted if function is guaranteed not to do a slow path
	 * identifier access that might be caught by locally declared variables.
	 * The varmap can also be omitted if it turns out empty of actual
	 * register mappings after a cleanup.  When debugging is enabled, we
	 * always need the varmap to be able to lookup variables at any point.
	 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	DUK_DD(DUK_DDPRINT("keeping _Varmap because debugger support is enabled"));
	keep_varmap = 1;
#else
	if (func->id_access_slow_own ||   /* directly uses slow accesses that may match own variables */
	    func->id_access_arguments ||  /* accesses 'arguments' directly */
	    func->may_direct_eval ||      /* may indirectly slow access through a direct eval */
	    funcs_count > 0) {            /* has inner functions which may slow access (XXX: this can be optimized by looking at the inner functions) */
		DUK_DD(DUK_DDPRINT("keeping _Varmap because of direct eval, slow path access that may match local variables, or presence of inner functions"));
		keep_varmap = 1;
	} else {
		DUK_DD(DUK_DDPRINT("dropping _Varmap"));
		keep_varmap = 0;
	}
#endif

	if (keep_varmap) {
		duk_int_t num_used;
		duk_dup(thr, func->varmap_idx);
		num_used = duk__cleanup_varmap(comp_ctx);
		DUK_DDD(DUK_DDDPRINT("cleaned up varmap: %!T (num_used=%ld)",
		                     (duk_tval *) duk_get_tval(thr, -1), (long) num_used));

		if (num_used > 0) {
			duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_VARMAP, DUK_PROPDESC_FLAGS_NONE);
		} else {
			DUK_DD(DUK_DDPRINT("varmap is empty after cleanup -> no need to add"));
			duk_pop(thr);
		}
	}

	/* _Formals: omitted if function is guaranteed not to need a (non-strict)
	 * arguments object, and _Formals.length matches nargs exactly.
	 *
	 * Non-arrow functions can't see an outer function's 'argument' binding
	 * (because they have their own), but arrow functions can.  When arrow
	 * functions are added, this condition would need to be added:
	 *     inner_arrow_funcs_count > 0   inner arrow functions may access 'arguments'
	 */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	DUK_DD(DUK_DDPRINT("keeping _Formals because debugger support is enabled"));
	keep_formals = 1;
#else
	formals_length = duk_get_length(thr, func->argnames_idx);
	if (formals_length != (duk_size_t) h_res->nargs) {
		/* Nargs not enough for closure .length: keep _Formals regardless
		 * of its length.  Shouldn't happen in practice at the moment.
		 */
		DUK_DD(DUK_DDPRINT("keeping _Formals because _Formals.length != nargs"));
		keep_formals = 1;
	} else if ((func->id_access_arguments || func->may_direct_eval) &&
	           (formals_length > 0)) {
		/* Direct eval (may access 'arguments') or accesses 'arguments'
		 * explicitly: keep _Formals unless it is zero length.
		 */
		DUK_DD(DUK_DDPRINT("keeping _Formals because of direct eval or explicit access to 'arguments', and _Formals.length != 0"));
		keep_formals = 1;
	} else {
		DUK_DD(DUK_DDPRINT("omitting _Formals, nargs matches _Formals.length, so no properties added"));
		keep_formals = 0;
	}
#endif

	if (keep_formals) {
		duk_dup(thr, func->argnames_idx);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_FORMALS, DUK_PROPDESC_FLAGS_NONE);
	}

	/* name */
#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	if (func->h_name) {
		duk_push_hstring(thr, func->h_name);
		DUK_DD(DUK_DDPRINT("setting function template .name to %!T", duk_get_tval(thr, -1)));
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_NONE);
	}
#endif  /* DUK_USE_FUNC_NAME_PROPERTY */

	/* _Source */
#if defined(DUK_USE_NONSTD_FUNC_SOURCE_PROPERTY)
	if (0) {
		/* XXX: Currently function source code is not stored, as it is not
		 * required by the standard.  Source code should not be stored by
		 * default (user should enable it explicitly), and the source should
		 * probably be compressed with a trivial text compressor; average
		 * compression of 20-30% is quite easy to achieve even with a trivial
		 * compressor (RLE + backwards lookup).
		 *
		 * Debugging needs source code to be useful: sometimes input code is
		 * not found in files as it may be generated and then eval()'d, given
		 * by dynamic C code, etc.
		 *
		 * Other issues:
		 *
		 *   - Need tokenizer indices for start and end to substring
		 *   - Always normalize function declaration part?
		 *   - If we keep _Formals, only need to store body
		 */

		/*
		 *  For global or eval code this is straightforward.  For functions
		 *  created with the Function constructor we only get the source for
		 *  the body and must manufacture the "function ..." part.
		 *
		 *  For instance, for constructed functions (v8):
		 *
		 *    > a = new Function("foo", "bar", "print(foo)");
		 *    [Function]
		 *    > a.toString()
		 *    'function anonymous(foo,bar) {\nprint(foo)\n}'
		 *
		 *  Similarly for e.g. getters (v8):
		 *
		 *    > x = { get a(foo,bar) { print(foo); } }
		 *    { a: [Getter] }
		 *    > Object.getOwnPropertyDescriptor(x, 'a').get.toString()
		 *    'function a(foo,bar) { print(foo); }'
		 */

#if 0
		duk_push_literal(thr, "XXX");
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_SOURCE, DUK_PROPDESC_FLAGS_NONE);
#endif
	}
#endif  /* DUK_USE_NONSTD_FUNC_SOURCE_PROPERTY */

	/* _Pc2line */
#if defined(DUK_USE_PC2LINE)
	if (1) {
		/*
		 *  Size-optimized pc->line mapping.
		 */

		DUK_ASSERT(code_count <= DUK_COMPILER_MAX_BYTECODE_LENGTH);
		duk_hobject_pc2line_pack(thr, q_instr, (duk_uint_fast32_t) code_count);  /* -> pushes fixed buffer */
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_PC2LINE, DUK_PROPDESC_FLAGS_NONE);

		/* XXX: if assertions enabled, walk through all valid PCs
		 * and check line mapping.
		 */
	}
#endif  /* DUK_USE_PC2LINE */

	/* fileName */
#if defined(DUK_USE_FUNC_FILENAME_PROPERTY)
	if (comp_ctx->h_filename) {
		/*
		 *  Source filename (or equivalent), for identifying thrown errors.
		 */

		duk_push_hstring(thr, comp_ctx->h_filename);
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_NONE);
	}
#endif

	DUK_DD(DUK_DDPRINT("converted function: %!ixT",
	                   (duk_tval *) duk_get_tval(thr, -1)));

	/*
	 *  Compact the function template.
	 */

	duk_compact_m1(thr);

	/*
	 *  Debug dumping
	 */

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
	{
		duk_hcompfunc *h;
		duk_instr_t *p, *p_start, *p_end;

		h = (duk_hcompfunc *) duk_get_hobject(thr, -1);
		p_start = (duk_instr_t *) DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, h);
		p_end = (duk_instr_t *) DUK_HCOMPFUNC_GET_CODE_END(thr->heap, h);

		p = p_start;
		while (p < p_end) {
			DUK_DDD(DUK_DDDPRINT("BC %04ld: %!I        ; 0x%08lx op=%ld (%!X) a=%ld b=%ld c=%ld",
			                     (long) (p - p_start),
			                     (duk_instr_t) (*p),
			                     (unsigned long) (*p),
			                     (long) DUK_DEC_OP(*p),
			                     (long) DUK_DEC_OP(*p),
			                     (long) DUK_DEC_A(*p),
			                     (long) DUK_DEC_B(*p),
			                     (long) DUK_DEC_C(*p)));
			p++;
		}
	}
#endif
}

/*
 *  Code emission helpers
 *
 *  Some emission helpers understand the range of target and source reg/const
 *  values and automatically emit shuffling code if necessary.  This is the
 *  case when the slot in question (A, B, C) is used in the standard way and
 *  for opcodes the emission helpers explicitly understand (like DUK_OP_MPUTOBJ).
 *
 *  The standard way is that:
 *    - slot A is a target register
 *    - slot B is a source register/constant
 *    - slot C is a source register/constant
 *
 *  If a slot is used in a non-standard way the caller must indicate this
 *  somehow.  If a slot is used as a target instead of a source (or vice
 *  versa), this can be indicated with a flag to trigger proper shuffling
 *  (e.g. DUK__EMIT_FLAG_B_IS_TARGET).  If the value in the slot is not
 *  register/const related at all, the caller must ensure that the raw value
 *  fits into the corresponding slot so as to not trigger shuffling.  The
 *  caller must set a "no shuffle" flag to ensure compilation fails if
 *  shuffling were to be triggered because of an internal error.
 *
 *  For slots B and C the raw slot size is 9 bits but one bit is reserved for
 *  the reg/const indicator.  To use the full 9-bit range for a raw value,
 *  shuffling must be disabled with the DUK__EMIT_FLAG_NO_SHUFFLE_{B,C} flag.
 *  Shuffling is only done for A, B, and C slots, not the larger BC or ABC slots.
 *
 *  There is call handling specific understanding in the A-B-C emitter to
 *  convert call setup and call instructions into indirect ones if necessary.
 */

/* Code emission flags, passed in the 'opcode' field.  Opcode + flags
 * fit into 16 bits for now, so use duk_small_uint_t.
 */
#define DUK__EMIT_FLAG_NO_SHUFFLE_A      (1 << 8)
#define DUK__EMIT_FLAG_NO_SHUFFLE_B      (1 << 9)
#define DUK__EMIT_FLAG_NO_SHUFFLE_C      (1 << 10)
#define DUK__EMIT_FLAG_A_IS_SOURCE       (1 << 11)  /* slot A is a source (default: target) */
#define DUK__EMIT_FLAG_B_IS_TARGET       (1 << 12)  /* slot B is a target (default: source) */
#define DUK__EMIT_FLAG_C_IS_TARGET       (1 << 13)  /* slot C is a target (default: source) */
#define DUK__EMIT_FLAG_BC_REGCONST       (1 << 14)  /* slots B and C are reg/const */
#define DUK__EMIT_FLAG_RESERVE_JUMPSLOT  (1 << 15)  /* reserve a jumpslot after instr before target spilling, used for NEXTENUM */

/* XXX: macro smaller than call? */
DUK_LOCAL duk_int_t duk__get_current_pc(duk_compiler_ctx *comp_ctx) {
	duk_compiler_func *func;
	func = &comp_ctx->curr_func;
	return (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &func->bw_code) / sizeof(duk_compiler_instr));
}

DUK_LOCAL duk_compiler_instr *duk__get_instr_ptr(duk_compiler_ctx *comp_ctx, duk_int_t pc) {
	DUK_ASSERT(pc >= 0);
	DUK_ASSERT((duk_size_t) pc < (duk_size_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr)));
	return ((duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code)) + pc;
}

/* emit instruction; could return PC but that's not needed in the majority
 * of cases.
 */
DUK_LOCAL void duk__emit(duk_compiler_ctx *comp_ctx, duk_instr_t ins) {
#if defined(DUK_USE_PC2LINE)
	duk_int_t line;
#endif
	duk_compiler_instr *instr;

	DUK_DDD(DUK_DDDPRINT("duk__emit: 0x%08lx curr_token.start_line=%ld prev_token.start_line=%ld pc=%ld --> %!I",
	                     (unsigned long) ins,
	                     (long) comp_ctx->curr_token.start_line,
	                     (long) comp_ctx->prev_token.start_line,
	                     (long) duk__get_current_pc(comp_ctx),
	                     (duk_instr_t) ins));

	instr = (duk_compiler_instr *) (void *) DUK_BW_ENSURE_GETPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));
	DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));

#if defined(DUK_USE_PC2LINE)
	/* The line number tracking is a bit inconsistent right now, which
	 * affects debugger accuracy.  Mostly call sites emit opcodes when
	 * they have parsed a token (say a terminating semicolon) and called
	 * duk__advance().  In this case the line number of the previous
	 * token is the most accurate one (except in prologue where
	 * prev_token.start_line is 0).  This is probably not 100% correct
	 * right now.
	 */
	/* approximation, close enough */
	line = comp_ctx->prev_token.start_line;
	if (line == 0) {
		line = comp_ctx->curr_token.start_line;
	}
#endif

	instr->ins = ins;
#if defined(DUK_USE_PC2LINE)
	instr->line = (duk_uint32_t) line;
#endif
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	if (line < comp_ctx->curr_func.min_line) {
		comp_ctx->curr_func.min_line = line;
	}
	if (line > comp_ctx->curr_func.max_line) {
		comp_ctx->curr_func.max_line = line;
	}
#endif

	/* Limit checks for bytecode byte size and line number. */
	if (DUK_UNLIKELY(DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) > DUK_USE_ESBC_MAX_BYTES)) {
		goto fail_bc_limit;
	}
#if defined(DUK_USE_PC2LINE) && defined(DUK_USE_ESBC_LIMITS)
#if defined(DUK_USE_BUFLEN16)
	/* Buffer length is bounded to 0xffff automatically, avoid compile warning. */
	if (DUK_UNLIKELY(line > DUK_USE_ESBC_MAX_LINENUMBER)) {
		goto fail_bc_limit;
	}
#else
	if (DUK_UNLIKELY(line > DUK_USE_ESBC_MAX_LINENUMBER)) {
		goto fail_bc_limit;
	}
#endif
#endif

	return;

  fail_bc_limit:
	DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_BYTECODE_LIMIT);
	DUK_WO_NORETURN(return;);
}

/* Update function min/max line from current token.  Needed to improve
 * function line range information for debugging, so that e.g. opening
 * curly brace is covered by line range even when no opcodes are emitted
 * for the line containing the brace.
 */
DUK_LOCAL void duk__update_lineinfo_currtoken(duk_compiler_ctx *comp_ctx) {
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	duk_int_t line;

	line = comp_ctx->curr_token.start_line;
	if (line == 0) {
		return;
	}
	if (line < comp_ctx->curr_func.min_line) {
		comp_ctx->curr_func.min_line = line;
	}
	if (line > comp_ctx->curr_func.max_line) {
		comp_ctx->curr_func.max_line = line;
	}
#else
	DUK_UNREF(comp_ctx);
#endif
}

DUK_LOCAL void duk__emit_op_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t op) {
	duk__emit(comp_ctx, DUK_ENC_OP_ABC(op, 0));
}

/* Important main primitive. */
DUK_LOCAL void duk__emit_a_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b, duk_regconst_t c) {
	duk_instr_t ins = 0;
	duk_int_t a_out = -1;
	duk_int_t b_out = -1;
	duk_int_t c_out = -1;
	duk_int_t tmp;
	duk_small_uint_t op = op_flags & 0xffU;

	DUK_DDD(DUK_DDDPRINT("emit: op_flags=%04lx, a=%ld, b=%ld, c=%ld",
	                     (unsigned long) op_flags, (long) a, (long) b, (long) c));

	/* We could rely on max temp/const checks: if they don't exceed BC
	 * limit, nothing here can either (just asserts would be enough).
	 * Currently we check for the limits, which provides additional
	 * protection against creating invalid bytecode due to compiler
	 * bugs.
	 */

	DUK_ASSERT_DISABLE((op_flags & 0xff) >= DUK_BC_OP_MIN);  /* unsigned */
	DUK_ASSERT((op_flags & 0xff) <= DUK_BC_OP_MAX);
	DUK_ASSERT(DUK__ISREG(a));
	DUK_ASSERT(b != -1);  /* Not 'none'. */
	DUK_ASSERT(c != -1);  /* Not 'none'. */

	/* Input shuffling happens before the actual operation, while output
	 * shuffling happens afterwards.  Output shuffling decisions are still
	 * made at the same time to reduce branch clutter; output shuffle decisions
	 * are recorded into X_out variables.
	 */

	/* Slot A: currently no support for reg/const. */

#if defined(DUK_USE_SHUFFLE_TORTURE)
	if (a <= DUK_BC_A_MAX && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A)) {
#else
	if (a <= DUK_BC_A_MAX) {
#endif
		;
	} else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A) {
		DUK_D(DUK_DPRINT("out of regs: 'a' (reg) needs shuffling but shuffle prohibited, a: %ld", (long) a));
		goto error_outofregs;
	} else if (a <= DUK_BC_BC_MAX) {
		comp_ctx->curr_func.needs_shuffle = 1;
		tmp = comp_ctx->curr_func.shuffle1;
		if (op_flags & DUK__EMIT_FLAG_A_IS_SOURCE) {
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, a));
		} else {
			/* Output shuffle needed after main operation */
			a_out = a;

			/* The DUK_OP_CSVAR output shuffle assumes shuffle registers are
			 * consecutive.
			 */
			DUK_ASSERT((comp_ctx->curr_func.shuffle1 == 0 && comp_ctx->curr_func.shuffle2 == 0) ||
			           (comp_ctx->curr_func.shuffle2 == comp_ctx->curr_func.shuffle1 + 1));
			if (op == DUK_OP_CSVAR) {
				/* For CSVAR the limit is one smaller because output shuffle
				 * must be able to express 'a + 1' in BC.
				 */
				if (a + 1 > DUK_BC_BC_MAX) {
					goto error_outofregs;
				}
			}
		}
		a = tmp;
	} else {
		DUK_D(DUK_DPRINT("out of regs: 'a' (reg) needs shuffling but does not fit into BC, a: %ld", (long) a));
		goto error_outofregs;
	}

	/* Slot B: reg/const support, mapped to bit 0 of opcode. */

	if ((b & DUK__CONST_MARKER) != 0) {
		DUK_ASSERT((op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B) == 0);
		DUK_ASSERT((op_flags & DUK__EMIT_FLAG_B_IS_TARGET) == 0);
		b = b & ~DUK__CONST_MARKER;
#if defined(DUK_USE_SHUFFLE_TORTURE)
		if (0) {
#else
		if (b <= 0xff) {
#endif
			if (op_flags & DUK__EMIT_FLAG_BC_REGCONST) {
				/* Opcode follows B/C reg/const convention. */
				DUK_ASSERT((op & 0x01) == 0);
				ins |= DUK_ENC_OP_A_B_C(0x01, 0, 0, 0);  /* const flag for B */
			} else {
				DUK_D(DUK_DPRINT("B is const, opcode is not B/C reg/const: %x", op_flags));
			}
		} else if (b <= DUK_BC_BC_MAX) {
			comp_ctx->curr_func.needs_shuffle = 1;
			tmp = comp_ctx->curr_func.shuffle2;
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDCONST, tmp, b));
			b = tmp;
		} else {
			DUK_D(DUK_DPRINT("out of regs: 'b' (const) needs shuffling but does not fit into BC, b: %ld", (long) b));
			goto error_outofregs;
		}
	} else {
#if defined(DUK_USE_SHUFFLE_TORTURE)
		if (b <= 0xff && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B)) {
#else
		if (b <= 0xff) {
#endif
			;
		} else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B) {
			if (b > DUK_BC_B_MAX) {
				/* Note: 0xff != DUK_BC_B_MAX */
				DUK_D(DUK_DPRINT("out of regs: 'b' (reg) needs shuffling but shuffle prohibited, b: %ld", (long) b));
				goto error_outofregs;
			}
		} else if (b <= DUK_BC_BC_MAX) {
			comp_ctx->curr_func.needs_shuffle = 1;
			tmp = comp_ctx->curr_func.shuffle2;
			if (op_flags & DUK__EMIT_FLAG_B_IS_TARGET) {
				/* Output shuffle needed after main operation */
				b_out = b;
			}
			if (!(op_flags & DUK__EMIT_FLAG_B_IS_TARGET)) {
				if (op == DUK_OP_MPUTOBJ || op == DUK_OP_MPUTARR) {
					/* Special handling for MPUTOBJ/MPUTARR shuffling.
					 * For each, slot B identifies the first register of a range
					 * of registers, so normal shuffling won't work.  Instead,
					 * an indirect version of the opcode is used.
					 */
					DUK_ASSERT((op_flags & DUK__EMIT_FLAG_B_IS_TARGET) == 0);
					duk__emit_load_int32_noshuffle(comp_ctx, tmp, b);
					DUK_ASSERT(DUK_OP_MPUTOBJI == DUK_OP_MPUTOBJ + 1);
					DUK_ASSERT(DUK_OP_MPUTARRI == DUK_OP_MPUTARR + 1);
					op_flags++;  /* indirect opcode follows direct */
				} else {
					duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, b));
				}
			}
			b = tmp;
		} else {
			DUK_D(DUK_DPRINT("out of regs: 'b' (reg) needs shuffling but does not fit into BC, b: %ld", (long) b));
			goto error_outofregs;
		}
	}

	/* Slot C: reg/const support, mapped to bit 1 of opcode. */

	if ((c & DUK__CONST_MARKER) != 0) {
		DUK_ASSERT((op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C) == 0);
		DUK_ASSERT((op_flags & DUK__EMIT_FLAG_C_IS_TARGET) == 0);
		c = c & ~DUK__CONST_MARKER;
#if defined(DUK_USE_SHUFFLE_TORTURE)
		if (0) {
#else
		if (c <= 0xff) {
#endif
			if (op_flags & DUK__EMIT_FLAG_BC_REGCONST) {
				/* Opcode follows B/C reg/const convention. */
				DUK_ASSERT((op & 0x02) == 0);
				ins |= DUK_ENC_OP_A_B_C(0x02, 0, 0, 0);  /* const flag for C */
			} else {
				DUK_D(DUK_DPRINT("C is const, opcode is not B/C reg/const: %x", op_flags));
			}
		} else if (c <= DUK_BC_BC_MAX) {
			comp_ctx->curr_func.needs_shuffle = 1;
			tmp = comp_ctx->curr_func.shuffle3;
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDCONST, tmp, c));
			c = tmp;
		} else {
			DUK_D(DUK_DPRINT("out of regs: 'c' (const) needs shuffling but does not fit into BC, c: %ld", (long) c));
			goto error_outofregs;
		}
	} else {
#if defined(DUK_USE_SHUFFLE_TORTURE)
		if (c <= 0xff && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C)) {
#else
		if (c <= 0xff) {
#endif
			;
		} else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C) {
			if (c > DUK_BC_C_MAX) {
				/* Note: 0xff != DUK_BC_C_MAX */
				DUK_D(DUK_DPRINT("out of regs: 'c' (reg) needs shuffling but shuffle prohibited, c: %ld", (long) c));
				goto error_outofregs;
			}
		} else if (c <= DUK_BC_BC_MAX) {
			comp_ctx->curr_func.needs_shuffle = 1;
			tmp = comp_ctx->curr_func.shuffle3;
			if (op_flags & DUK__EMIT_FLAG_C_IS_TARGET) {
				/* Output shuffle needed after main operation */
				c_out = c;
			} else {
				duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, c));
			}
			c = tmp;
		} else {
			DUK_D(DUK_DPRINT("out of regs: 'c' (reg) needs shuffling but does not fit into BC, c: %ld", (long) c));
			goto error_outofregs;
		}
	}

	/* Main operation */

	DUK_ASSERT(a >= DUK_BC_A_MIN);
	DUK_ASSERT(a <= DUK_BC_A_MAX);
	DUK_ASSERT(b >= DUK_BC_B_MIN);
	DUK_ASSERT(b <= DUK_BC_B_MAX);
	DUK_ASSERT(c >= DUK_BC_C_MIN);
	DUK_ASSERT(c <= DUK_BC_C_MAX);

	ins |= DUK_ENC_OP_A_B_C(op_flags & 0xff, a, b, c);
	duk__emit(comp_ctx, ins);

	/* NEXTENUM needs a jump slot right after the main instruction.
	 * When the JUMP is taken, output spilling is not needed so this
	 * workaround is possible.  The jump slot PC is exceptionally
	 * plumbed through comp_ctx to minimize call sites.
	 */
	if (op_flags & DUK__EMIT_FLAG_RESERVE_JUMPSLOT) {
		comp_ctx->emit_jumpslot_pc = duk__get_current_pc(comp_ctx);
		duk__emit_abc(comp_ctx, DUK_OP_JUMP, 0);
	}

	/* Output shuffling: only one output register is realistically possible.
	 *
	 * (Zero would normally be an OK marker value: if the target register
	 * was zero, it would never be shuffled.  But with DUK_USE_SHUFFLE_TORTURE
	 * this is no longer true, so use -1 as a marker instead.)
	 */

	if (a_out >= 0) {
		DUK_ASSERT(b_out < 0);
		DUK_ASSERT(c_out < 0);
		duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, a, a_out));

		if (op == DUK_OP_CSVAR) {
			/* Special handling for CSVAR shuffling.  The variable lookup
			 * results in a <value, this binding> pair in successive
			 * registers so use two shuffle registers and two output
			 * loads.  (In practice this is dead code because temp/const
			 * limit is reached first.)
			 */
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, a + 1, a_out + 1));
		}
	} else if (b_out >= 0) {
		DUK_ASSERT(a_out < 0);
		DUK_ASSERT(c_out < 0);
		duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, b, b_out));
	} else if (c_out >= 0) {
		DUK_ASSERT(b_out < 0);
		DUK_ASSERT(c_out < 0);
		duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, c, c_out));
	}

	return;

 error_outofregs:
	DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
	DUK_WO_NORETURN(return;);
}

/* For many of the helpers below it'd be technically correct to add
 * "no shuffle" flags for parameters passed in as zero.  For example,
 * duk__emit_a_b() should call duk__emit_a_b_c() with C set to 0, and
 * DUK__EMIT_FLAG_NO_SHUFFLE_C added to op_flags.  However, since the
 * C value is 0, it'll never get shuffled so adding the flag is just
 * unnecessary additional code.  This is unfortunately not true for
 * "shuffle torture" mode which needs special handling.
 */

DUK_LOCAL void duk__emit_a_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b) {
#if defined(DUK_USE_SHUFFLE_TORTURE)
	op_flags |= DUK__EMIT_FLAG_NO_SHUFFLE_C;
#endif
	duk__emit_a_b_c(comp_ctx, op_flags, a, b, 0);
}

DUK_LOCAL void duk__emit_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t b, duk_regconst_t c) {
#if defined(DUK_USE_SHUFFLE_TORTURE)
	op_flags |= DUK__EMIT_FLAG_NO_SHUFFLE_A;
#endif
	duk__emit_a_b_c(comp_ctx, op_flags, 0, b, c);
}

#if 0  /* unused */
DUK_LOCAL void duk__emit_a(duk_compiler_ctx *comp_ctx, int op_flags, int a) {
#if defined(DUK_USE_SHUFFLE_TORTURE)
	op_flags |= DUK__EMIT_FLAG_NO_SHUFFLE_B | DUK__EMIT_FLAG_NO_SHUFFLE_C;
#endif
	duk__emit_a_b_c(comp_ctx, op_flags, a, 0, 0);
}
#endif

#if 0  /* unused */
DUK_LOCAL void duk__emit_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t b) {
#if defined(DUK_USE_SHUFFLE_TORTURE)
	op_flags |= DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_C;
#endif
	duk__emit_a_b_c(comp_ctx, op_flags, 0, b, 0);
}
#endif

DUK_LOCAL void duk__emit_a_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t bc) {
	duk_instr_t ins;
	duk_int_t tmp;

	/* allow caller to give a const number with the DUK__CONST_MARKER */
	DUK_ASSERT(bc != -1);  /* Not 'none'. */
	bc = bc & (~DUK__CONST_MARKER);

	DUK_ASSERT_DISABLE((op_flags & 0xff) >= DUK_BC_OP_MIN);  /* unsigned */
	DUK_ASSERT((op_flags & 0xff) <= DUK_BC_OP_MAX);
	DUK_ASSERT(bc >= DUK_BC_BC_MIN);
	DUK_ASSERT(bc <= DUK_BC_BC_MAX);
	DUK_ASSERT((bc & DUK__CONST_MARKER) == 0);

	if (bc <= DUK_BC_BC_MAX) {
		;
	} else {
		/* No BC shuffling now. */
		goto error_outofregs;
	}

#if defined(DUK_USE_SHUFFLE_TORTURE)
	if (a <= DUK_BC_A_MAX && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A)) {
#else
	if (a <= DUK_BC_A_MAX) {
#endif
		ins = DUK_ENC_OP_A_BC(op_flags & 0xff, a, bc);
		duk__emit(comp_ctx, ins);
	} else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A) {
		goto error_outofregs;
	} else if ((op_flags & 0xf0U) == DUK_OP_CALL0) {
		comp_ctx->curr_func.needs_shuffle = 1;
		tmp = comp_ctx->curr_func.shuffle1;
		duk__emit_load_int32_noshuffle(comp_ctx, tmp, a);
		op_flags |= DUK_BC_CALL_FLAG_INDIRECT;
		ins = DUK_ENC_OP_A_BC(op_flags & 0xff, tmp, bc);
		duk__emit(comp_ctx, ins);
	} else if (a <= DUK_BC_BC_MAX) {
		comp_ctx->curr_func.needs_shuffle = 1;
		tmp = comp_ctx->curr_func.shuffle1;
		ins = DUK_ENC_OP_A_BC(op_flags & 0xff, tmp, bc);
		if (op_flags & DUK__EMIT_FLAG_A_IS_SOURCE) {
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, a));
			duk__emit(comp_ctx, ins);
		} else {
			duk__emit(comp_ctx, ins);
			duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, tmp, a));
		}
	} else {
		goto error_outofregs;
	}
	return;

 error_outofregs:
	DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__emit_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t bc) {
#if defined(DUK_USE_SHUFFLE_TORTURE)
	op |= DUK__EMIT_FLAG_NO_SHUFFLE_A;
#endif
	duk__emit_a_bc(comp_ctx, op, 0, bc);
}

DUK_LOCAL void duk__emit_abc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t abc) {
	duk_instr_t ins;

	DUK_ASSERT_DISABLE(op >= DUK_BC_OP_MIN);  /* unsigned */
	DUK_ASSERT(op <= DUK_BC_OP_MAX);
	DUK_ASSERT_DISABLE(abc >= DUK_BC_ABC_MIN);  /* unsigned */
	DUK_ASSERT(abc <= DUK_BC_ABC_MAX);
	DUK_ASSERT((abc & DUK__CONST_MARKER) == 0);
	DUK_ASSERT(abc != -1);  /* Not 'none'. */

	if (abc <= DUK_BC_ABC_MAX) {
		;
	} else {
		goto error_outofregs;
	}
	ins = DUK_ENC_OP_ABC(op, abc);
	DUK_DDD(DUK_DDDPRINT("duk__emit_abc: 0x%08lx line=%ld pc=%ld op=%ld (%!X) abc=%ld (%!I)",
	                     (unsigned long) ins, (long) comp_ctx->curr_token.start_line,
	                     (long) duk__get_current_pc(comp_ctx), (long) op, (long) op,
	                     (long) abc, (duk_instr_t) ins));
	duk__emit(comp_ctx, ins);
	return;

 error_outofregs:
	DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__emit_load_int32_raw(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val, duk_small_uint_t op_flags) {
	/* XXX: Shuffling support could be implemented here so that LDINT+LDINTX
	 * would only shuffle once (instead of twice).  The current code works
	 * though, and has a smaller compiler footprint.
	 */

	if ((val >= (duk_int32_t) DUK_BC_BC_MIN - (duk_int32_t) DUK_BC_LDINT_BIAS) &&
	    (val <= (duk_int32_t) DUK_BC_BC_MAX - (duk_int32_t) DUK_BC_LDINT_BIAS)) {
		DUK_DDD(DUK_DDDPRINT("emit LDINT to reg %ld for %ld", (long) reg, (long) val));
		duk__emit_a_bc(comp_ctx, DUK_OP_LDINT | op_flags, reg, (duk_regconst_t) (val + (duk_int32_t) DUK_BC_LDINT_BIAS));
	} else {
		duk_int32_t hi = val >> DUK_BC_LDINTX_SHIFT;
		duk_int32_t lo = val & ((((duk_int32_t) 1) << DUK_BC_LDINTX_SHIFT) - 1);
		DUK_ASSERT(lo >= 0);
		DUK_DDD(DUK_DDDPRINT("emit LDINT+LDINTX to reg %ld for %ld -> hi %ld, lo %ld",
		                     (long) reg, (long) val, (long) hi, (long) lo));
		duk__emit_a_bc(comp_ctx, DUK_OP_LDINT | op_flags, reg, (duk_regconst_t) (hi + (duk_int32_t) DUK_BC_LDINT_BIAS));
		duk__emit_a_bc(comp_ctx, DUK_OP_LDINTX | op_flags, reg, (duk_regconst_t) lo);
	}
}

DUK_LOCAL void duk__emit_load_int32(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val) {
	duk__emit_load_int32_raw(comp_ctx, reg, val, 0 /*op_flags*/);
}

#if defined(DUK_USE_SHUFFLE_TORTURE)
/* Used by duk__emit*() calls so that we don't shuffle the loadints that
 * are needed to handle indirect opcodes.
 */
DUK_LOCAL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val) {
	duk__emit_load_int32_raw(comp_ctx, reg, val, DUK__EMIT_FLAG_NO_SHUFFLE_A /*op_flags*/);
}
#else
DUK_LOCAL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_regconst_t reg, duk_int32_t val) {
	/* When torture not enabled, can just use the same helper because
	 * 'reg' won't get spilled.
	 */
	DUK_ASSERT(reg <= DUK_BC_A_MAX);
	duk__emit_load_int32(comp_ctx, reg, val);
}
#endif

DUK_LOCAL void duk__emit_jump(duk_compiler_ctx *comp_ctx, duk_int_t target_pc) {
	duk_int_t curr_pc;
	duk_int_t offset;

	curr_pc = (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr));
	offset = (duk_int_t) target_pc - (duk_int_t) curr_pc - 1;
	DUK_ASSERT(offset + DUK_BC_JUMP_BIAS >= DUK_BC_ABC_MIN);
	DUK_ASSERT(offset + DUK_BC_JUMP_BIAS <= DUK_BC_ABC_MAX);
	duk__emit_abc(comp_ctx, DUK_OP_JUMP, (duk_regconst_t) (offset + DUK_BC_JUMP_BIAS));
}

DUK_LOCAL duk_int_t duk__emit_jump_empty(duk_compiler_ctx *comp_ctx) {
	duk_int_t ret;

	ret = duk__get_current_pc(comp_ctx);  /* useful for patching jumps later */
	duk__emit_op_only(comp_ctx, DUK_OP_JUMP);
	return ret;
}

/* Insert an empty jump in the middle of code emitted earlier.  This is
 * currently needed for compiling for-in.
 */
DUK_LOCAL void duk__insert_jump_entry(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc) {
#if defined(DUK_USE_PC2LINE)
	duk_int_t line;
#endif
	duk_compiler_instr *instr;
	duk_size_t offset;

	DUK_ASSERT(jump_pc >= 0);
	offset = (duk_size_t) jump_pc * sizeof(duk_compiler_instr);
	instr = (duk_compiler_instr *) (void *)
	        DUK_BW_INSERT_ENSURE_AREA(comp_ctx->thr,
	                                  &comp_ctx->curr_func.bw_code,
	                                  offset,
	                                  sizeof(duk_compiler_instr));

#if defined(DUK_USE_PC2LINE)
	line = comp_ctx->curr_token.start_line;  /* approximation, close enough */
#endif
	instr->ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, 0);
#if defined(DUK_USE_PC2LINE)
	instr->line = (duk_uint32_t) line;
#endif

	DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));
	if (DUK_UNLIKELY(DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) > DUK_USE_ESBC_MAX_BYTES)) {
		goto fail_bc_limit;
	}
	return;

  fail_bc_limit:
	DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_BYTECODE_LIMIT);
	DUK_WO_NORETURN(return;);
}

/* Does not assume that jump_pc contains a DUK_OP_JUMP previously; this is intentional
 * to allow e.g. an INVALID opcode be overwritten with a JUMP (label management uses this).
 */
DUK_LOCAL void duk__patch_jump(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc, duk_int_t target_pc) {
	duk_compiler_instr *instr;
	duk_int_t offset;

	/* allow negative PCs, behave as a no-op */
	if (jump_pc < 0) {
		DUK_DDD(DUK_DDDPRINT("duk__patch_jump(): nop call, jump_pc=%ld (<0), target_pc=%ld",
		                     (long) jump_pc, (long) target_pc));
		return;
	}
	DUK_ASSERT(jump_pc >= 0);

	/* XXX: range assert */
	instr = duk__get_instr_ptr(comp_ctx, jump_pc);
	DUK_ASSERT(instr != NULL);

	/* XXX: range assert */
	offset = target_pc - jump_pc - 1;

	instr->ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, offset + DUK_BC_JUMP_BIAS);
	DUK_DDD(DUK_DDDPRINT("duk__patch_jump(): jump_pc=%ld, target_pc=%ld, offset=%ld",
	                     (long) jump_pc, (long) target_pc, (long) offset));
}

DUK_LOCAL void duk__patch_jump_here(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc) {
	duk__patch_jump(comp_ctx, jump_pc, duk__get_current_pc(comp_ctx));
}

DUK_LOCAL void duk__patch_trycatch(duk_compiler_ctx *comp_ctx, duk_int_t ldconst_pc, duk_int_t trycatch_pc, duk_regconst_t reg_catch, duk_regconst_t const_varname, duk_small_uint_t flags) {
	duk_compiler_instr *instr;

	DUK_ASSERT(DUK__ISREG(reg_catch));

	instr = duk__get_instr_ptr(comp_ctx, ldconst_pc);
	DUK_ASSERT(DUK_DEC_OP(instr->ins) == DUK_OP_LDCONST);
	DUK_ASSERT(instr != NULL);
	if (const_varname & DUK__CONST_MARKER) {
		/* Have a catch variable. */
		const_varname = const_varname & (~DUK__CONST_MARKER);
		if (reg_catch > DUK_BC_BC_MAX || const_varname > DUK_BC_BC_MAX) {
			/* Catch attempts to use out-of-range reg/const.  Without this
			 * check Duktape 0.12.0 could generate invalid code which caused
			 * an assert failure on execution.  This error is triggered e.g.
			 * for functions with a lot of constants and a try-catch statement.
			 * Shuffling or opcode semantics change is needed to fix the issue.
			 * See: test-bug-trycatch-many-constants.js.
			 */
			DUK_D(DUK_DPRINT("failed to patch trycatch: flags=%ld, reg_catch=%ld, const_varname=%ld (0x%08lx)",
			                 (long) flags, (long) reg_catch, (long) const_varname, (long) const_varname));
			DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
			DUK_WO_NORETURN(return;);
		}
		instr->ins |= DUK_ENC_OP_A_BC(0, 0, const_varname);
	} else {
		/* No catch variable, e.g. a try-finally; replace LDCONST with
		 * NOP to avoid a bogus LDCONST.
		 */
		instr->ins = DUK_ENC_OP(DUK_OP_NOP);
	}

	instr = duk__get_instr_ptr(comp_ctx, trycatch_pc);
	DUK_ASSERT(instr != NULL);
	DUK_ASSERT_DISABLE(flags >= DUK_BC_A_MIN);
	DUK_ASSERT(flags <= DUK_BC_A_MAX);
	instr->ins = DUK_ENC_OP_A_BC(DUK_OP_TRYCATCH, flags, reg_catch);
}

DUK_LOCAL void duk__emit_if_false_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst) {
	duk_small_uint_t op;

	op = DUK__ISREG(regconst) ? DUK_OP_IFFALSE_R : DUK_OP_IFFALSE_C;
	duk__emit_bc(comp_ctx, op, regconst);  /* helper will remove const flag */
}

DUK_LOCAL void duk__emit_if_true_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst) {
	duk_small_uint_t op;

	op = DUK__ISREG(regconst) ? DUK_OP_IFTRUE_R : DUK_OP_IFTRUE_C;
	duk__emit_bc(comp_ctx, op, regconst);  /* helper will remove const flag */
}

DUK_LOCAL void duk__emit_invalid(duk_compiler_ctx *comp_ctx) {
	duk__emit_op_only(comp_ctx, DUK_OP_INVALID);
}

/*
 *  Peephole optimizer for finished bytecode.
 *
 *  Does not remove opcodes; currently only straightens out unconditional
 *  jump chains which are generated by several control structures.
 */

DUK_LOCAL void duk__peephole_optimize_bytecode(duk_compiler_ctx *comp_ctx) {
	duk_compiler_instr *bc;
	duk_small_uint_t iter;
	duk_int_t i, n;
	duk_int_t count_opt;

	bc = (duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code);
#if defined(DUK_USE_BUFLEN16)
	/* No need to assert, buffer size maximum is 0xffff. */
#else
	DUK_ASSERT((duk_size_t) DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr) <= (duk_size_t) DUK_INT_MAX);  /* bytecode limits */
#endif
	n = (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr));

	for (iter = 0; iter < DUK_COMPILER_PEEPHOLE_MAXITER; iter++) {
		count_opt = 0;

		for (i = 0; i < n; i++) {
			duk_instr_t ins;
			duk_int_t target_pc1;
			duk_int_t target_pc2;

			ins = bc[i].ins;
			if (DUK_DEC_OP(ins) != DUK_OP_JUMP) {
				continue;
			}

			target_pc1 = i + 1 + (duk_int_t) DUK_DEC_ABC(ins) - (duk_int_t) DUK_BC_JUMP_BIAS;
			DUK_DDD(DUK_DDDPRINT("consider jump at pc %ld; target_pc=%ld", (long) i, (long) target_pc1));
			DUK_ASSERT(target_pc1 >= 0);
			DUK_ASSERT(target_pc1 < n);

			/* Note: if target_pc1 == i, we'll optimize a jump to itself.
			 * This does not need to be checked for explicitly; the case
			 * is rare and max iter breaks us out.
			 */

			ins = bc[target_pc1].ins;
			if (DUK_DEC_OP(ins) != DUK_OP_JUMP) {
				continue;
			}

			target_pc2 = target_pc1 + 1 + (duk_int_t) DUK_DEC_ABC(ins) - (duk_int_t) DUK_BC_JUMP_BIAS;

			DUK_DDD(DUK_DDDPRINT("optimizing jump at pc %ld; old target is %ld -> new target is %ld",
			                     (long) i, (long) target_pc1, (long) target_pc2));

			bc[i].ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, target_pc2 - (i + 1) + DUK_BC_JUMP_BIAS);

			count_opt++;
		}

		DUK_DD(DUK_DDPRINT("optimized %ld jumps on peephole round %ld", (long) count_opt, (long) (iter + 1)));

		if (count_opt == 0) {
			break;
		}
	}
}

/*
 *  Intermediate value helpers
 */

/* Flags for intermediate value coercions.  A flag for using a forced reg
 * is not needed, the forced_reg argument suffices and generates better
 * code (it is checked as it is used).
 */
/* XXX: DUK__IVAL_FLAG_REQUIRE_SHORT is passed but not currently implemented
 * by ispec/ivalue operations.
 */
#define DUK__IVAL_FLAG_ALLOW_CONST          (1 << 0)  /* allow a constant to be returned */
#define DUK__IVAL_FLAG_REQUIRE_TEMP         (1 << 1)  /* require a (mutable) temporary as a result (or a const if allowed) */
#define DUK__IVAL_FLAG_REQUIRE_SHORT        (1 << 2)  /* require a short (8-bit) reg/const which fits into bytecode B/C slot */

/* XXX: some code might benefit from DUK__SETTEMP_IFTEMP(thr,x) */

#if 0  /* enable manually for dumping */
#define DUK__DUMP_ISPEC(compctx,ispec) do { duk__dump_ispec((compctx), (ispec)); } while (0)
#define DUK__DUMP_IVALUE(compctx,ivalue) do { duk__dump_ivalue((compctx), (ivalue)); } while (0)

DUK_LOCAL void duk__dump_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *x) {
	DUK_D(DUK_DPRINT("ispec dump: t=%ld regconst=0x%08lx, valstack_idx=%ld, value=%!T",
	                 (long) x->t, (unsigned long) x->regconst, (long) x->valstack_idx,
	                 duk_get_tval(comp_ctx->thr, x->valstack_idx)));
}
DUK_LOCAL void duk__dump_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	DUK_D(DUK_DPRINT("ivalue dump: t=%ld op=%ld "
	                 "x1={t=%ld regconst=0x%08lx valstack_idx=%ld value=%!T} "
	                 "x2={t=%ld regconst=0x%08lx valstack_idx=%ld value=%!T}",
		         (long) x->t, (long) x->op,
	                 (long) x->x1.t, (unsigned long) x->x1.regconst, (long) x->x1.valstack_idx,
	                 duk_get_tval(comp_ctx->thr, x->x1.valstack_idx),
	                 (long) x->x2.t, (unsigned long) x->x2.regconst, (long) x->x2.valstack_idx,
	                 duk_get_tval(comp_ctx->thr, x->x2.valstack_idx)));
}
#else
#define DUK__DUMP_ISPEC(comp_ctx,x) do {} while (0)
#define DUK__DUMP_IVALUE(comp_ctx,x) do {} while (0)
#endif

DUK_LOCAL void duk__ivalue_regconst(duk_ivalue *x, duk_regconst_t regconst) {
	x->t = DUK_IVAL_PLAIN;
	x->x1.t = DUK_ISPEC_REGCONST;
	x->x1.regconst = regconst;
}

DUK_LOCAL void duk__ivalue_plain_fromstack(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	x->t = DUK_IVAL_PLAIN;
	x->x1.t = DUK_ISPEC_VALUE;
	duk_replace(comp_ctx->thr, x->x1.valstack_idx);
}

DUK_LOCAL void duk__ivalue_var_fromstack(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	x->t = DUK_IVAL_VAR;
	x->x1.t = DUK_ISPEC_VALUE;
	duk_replace(comp_ctx->thr, x->x1.valstack_idx);
}

DUK_LOCAL_DECL void duk__ivalue_var_hstring(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_hstring *h) {
	DUK_ASSERT(h != NULL);
	duk_push_hstring(comp_ctx->thr, h);
	duk__ivalue_var_fromstack(comp_ctx, x);
}

DUK_LOCAL void duk__copy_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *src, duk_ispec *dst) {
	dst->t = src->t;
	dst->regconst = src->regconst;
	duk_copy(comp_ctx->thr, src->valstack_idx, dst->valstack_idx);
}

DUK_LOCAL void duk__copy_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *src, duk_ivalue *dst) {
	dst->t = src->t;
	dst->op = src->op;
	dst->x1.t = src->x1.t;
	dst->x1.regconst = src->x1.regconst;
	dst->x2.t = src->x2.t;
	dst->x2.regconst = src->x2.regconst;
	duk_copy(comp_ctx->thr, src->x1.valstack_idx, dst->x1.valstack_idx);
	duk_copy(comp_ctx->thr, src->x2.valstack_idx, dst->x2.valstack_idx);
}

DUK_LOCAL duk_regconst_t duk__alloctemps(duk_compiler_ctx *comp_ctx, duk_small_int_t num) {
	duk_regconst_t res;

	res = comp_ctx->curr_func.temp_next;
	comp_ctx->curr_func.temp_next += num;

	if (comp_ctx->curr_func.temp_next > DUK__MAX_TEMPS) {  /* == DUK__MAX_TEMPS is OK */
		DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_TEMP_LIMIT);
		DUK_WO_NORETURN(return 0;);
	}

	/* maintain highest 'used' temporary, needed to figure out nregs of function */
	if (comp_ctx->curr_func.temp_next > comp_ctx->curr_func.temp_max) {
		comp_ctx->curr_func.temp_max = comp_ctx->curr_func.temp_next;
	}

	return res;
}

DUK_LOCAL duk_regconst_t duk__alloctemp(duk_compiler_ctx *comp_ctx) {
	return duk__alloctemps(comp_ctx, 1);
}

DUK_LOCAL void duk__settemp_checkmax(duk_compiler_ctx *comp_ctx, duk_regconst_t temp_next) {
	comp_ctx->curr_func.temp_next = temp_next;
	if (temp_next > comp_ctx->curr_func.temp_max) {
		comp_ctx->curr_func.temp_max = temp_next;
	}
}

/* get const for value at valstack top */
DUK_LOCAL duk_regconst_t duk__getconst(duk_compiler_ctx *comp_ctx) {
	duk_hthread *thr = comp_ctx->thr;
	duk_compiler_func *f = &comp_ctx->curr_func;
	duk_tval *tv1;
	duk_int_t i, n, n_check;

	n = (duk_int_t) duk_get_length(thr, f->consts_idx);

	tv1 = DUK_GET_TVAL_NEGIDX(thr, -1);
	DUK_ASSERT(tv1 != NULL);

#if defined(DUK_USE_FASTINT)
	/* Explicit check for fastint downgrade. */
	DUK_TVAL_CHKFAST_INPLACE_SLOW(tv1);
#endif

	/* Sanity workaround for handling functions with a large number of
	 * constants at least somewhat reasonably.  Otherwise checking whether
	 * we already have the constant would grow very slow (as it is O(N^2)).
	 */
	n_check = (n > DUK__GETCONST_MAX_CONSTS_CHECK ? DUK__GETCONST_MAX_CONSTS_CHECK : n);
	for (i = 0; i < n_check; i++) {
		duk_tval *tv2 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, f->h_consts, i);

		/* Strict equality is NOT enough, because we cannot use the same
		 * constant for e.g. +0 and -0.
		 */
		if (duk_js_samevalue(tv1, tv2)) {
			DUK_DDD(DUK_DDDPRINT("reused existing constant for %!T -> const index %ld",
			                     (duk_tval *) tv1, (long) i));
			duk_pop(thr);
			return (duk_regconst_t) i | (duk_regconst_t) DUK__CONST_MARKER;
		}
	}

	if (n > DUK__MAX_CONSTS) {
		DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_CONST_LIMIT);
		DUK_WO_NORETURN(return 0;);
	}

	DUK_DDD(DUK_DDDPRINT("allocating new constant for %!T -> const index %ld",
	                     (duk_tval *) tv1, (long) n));
	(void) duk_put_prop_index(thr, f->consts_idx, (duk_uarridx_t) n);  /* invalidates tv1, tv2 */
	return (duk_regconst_t) n | (duk_regconst_t) DUK__CONST_MARKER;
}

DUK_LOCAL duk_bool_t duk__const_needs_refcount(duk_compiler_ctx *comp_ctx, duk_regconst_t rc) {
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_compiler_func *f = &comp_ctx->curr_func;
	duk_bool_t ret;

	DUK_ASSERT((rc & DUK__CONST_MARKER) == 0);  /* caller removes const marker */
	(void) duk_get_prop_index(comp_ctx->thr, f->consts_idx, (duk_uarridx_t) rc);
	ret = !duk_is_number(comp_ctx->thr, -1);  /* now only number/string, so conservative check */
	duk_pop(comp_ctx->thr);
	return ret;
#else
	DUK_UNREF(comp_ctx);
	DUK_UNREF(rc);
	DUK_ASSERT((rc & DUK__CONST_MARKER) == 0);  /* caller removes const marker */
	return 0;
#endif
}

/* Get the value represented by an duk_ispec to a register or constant.
 * The caller can control the result by indicating whether or not:
 *
 *   (1) a constant is allowed (sometimes the caller needs the result to
 *       be in a register)
 *
 *   (2) a temporary register is required (usually when caller requires
 *       the register to be safely mutable; normally either a bound
 *       register or a temporary register are both OK)
 *
 *   (3) a forced register target needs to be used
 *
 * Bytecode may be emitted to generate the necessary value.  The return
 * value is either a register or a constant.
 */

DUK_LOCAL
duk_regconst_t duk__ispec_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                         duk_ispec *x,
                                         duk_regconst_t forced_reg,
                                         duk_small_uint_t flags) {
	duk_hthread *thr = comp_ctx->thr;

	DUK_DDD(DUK_DDDPRINT("duk__ispec_toregconst_raw(): x={%ld:%ld:%!T}, "
	                     "forced_reg=%ld, flags 0x%08lx: allow_const=%ld require_temp=%ld require_short=%ld",
	                     (long) x->t,
	                     (long) x->regconst,
	                     (duk_tval *) duk_get_tval(thr, x->valstack_idx),
	                     (long) forced_reg,
	                     (unsigned long) flags,
	                     (long) ((flags & DUK__IVAL_FLAG_ALLOW_CONST) ? 1 : 0),
	                     (long) ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) ? 1 : 0),
	                     (long) ((flags & DUK__IVAL_FLAG_REQUIRE_SHORT) ? 1 : 0)));

	switch (x->t) {
	case DUK_ISPEC_VALUE: {
		duk_tval *tv;

		tv = DUK_GET_TVAL_POSIDX(thr, x->valstack_idx);
		DUK_ASSERT(tv != NULL);

		switch (DUK_TVAL_GET_TAG(tv)) {
		case DUK_TAG_UNDEFINED: {
			/* Note: although there is no 'undefined' literal, undefined
			 * values can occur during compilation as a result of e.g.
			 * the 'void' operator.
			 */
			duk_regconst_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
			duk__emit_bc(comp_ctx, DUK_OP_LDUNDEF, dest);
			return dest;
		}
		case DUK_TAG_NULL: {
			duk_regconst_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
			duk__emit_bc(comp_ctx, DUK_OP_LDNULL, dest);
			return dest;
		}
		case DUK_TAG_BOOLEAN: {
			duk_regconst_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
			duk__emit_bc(comp_ctx,
			             (DUK_TVAL_GET_BOOLEAN(tv) ? DUK_OP_LDTRUE : DUK_OP_LDFALSE),
			             dest);
			return dest;
		}
		case DUK_TAG_POINTER: {
			DUK_UNREACHABLE();
			break;
		}
		case DUK_TAG_STRING: {
			duk_hstring *h;
			duk_regconst_t dest;
			duk_regconst_t constidx;

			h = DUK_TVAL_GET_STRING(tv);
			DUK_UNREF(h);
			DUK_ASSERT(h != NULL);

#if 0  /* XXX: to be implemented? */
			/* Use special opcodes to load short strings */
			if (DUK_HSTRING_GET_BYTELEN(h) <= 2) {
				/* Encode into a single opcode (18 bits can encode 1-2 bytes + length indicator) */
			} else if (DUK_HSTRING_GET_BYTELEN(h) <= 6) {
				/* Encode into a double constant (53 bits can encode 6*8 = 48 bits + 3-bit length */
			}
#endif
			duk_dup(thr, x->valstack_idx);
			constidx = duk__getconst(comp_ctx);

			if (flags & DUK__IVAL_FLAG_ALLOW_CONST) {
				return constidx;
			}

			dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
			duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, dest, constidx);
			return dest;
		}
		case DUK_TAG_OBJECT: {
			DUK_UNREACHABLE();
			break;
		}
		case DUK_TAG_BUFFER: {
			DUK_UNREACHABLE();
			break;
		}
		case DUK_TAG_LIGHTFUNC: {
			DUK_UNREACHABLE();
			break;
		}
#if defined(DUK_USE_FASTINT)
		case DUK_TAG_FASTINT:
#endif
		default: {
			/* number */
			duk_regconst_t dest;
			duk_regconst_t constidx;
			duk_double_t dval;
			duk_int32_t ival;

			DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
			dval = DUK_TVAL_GET_NUMBER(tv);

			if (!(flags & DUK__IVAL_FLAG_ALLOW_CONST)) {
				/* A number can be loaded either through a constant, using
				 * LDINT, or using LDINT+LDINTX.  LDINT is always a size win,
				 * LDINT+LDINTX is not if the constant is used multiple times.
				 * Currently always prefer LDINT+LDINTX over a double constant.
				 */

				if (duk_is_whole_get_int32_nonegzero(dval, &ival)) {
					dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
					duk__emit_load_int32(comp_ctx, dest, ival);
					return dest;
				}
			}

			duk_dup(thr, x->valstack_idx);
			constidx = duk__getconst(comp_ctx);

			if (flags & DUK__IVAL_FLAG_ALLOW_CONST) {
				return constidx;
			} else {
				dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
				duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, dest, constidx);
				return dest;
			}
		}
		}  /* end switch */
		goto fail_internal;  /* never here */
	}
	case DUK_ISPEC_REGCONST: {
		if (forced_reg >= 0) {
			if (DUK__ISCONST(x->regconst)) {
				duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, forced_reg, x->regconst);
			} else if (x->regconst != forced_reg) {
				duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, forced_reg, x->regconst);
			} else {
				; /* already in correct reg */
			}
			return forced_reg;
		}

		DUK_ASSERT(forced_reg < 0);
		if (DUK__ISCONST(x->regconst)) {
			if (!(flags & DUK__IVAL_FLAG_ALLOW_CONST)) {
				duk_regconst_t dest = DUK__ALLOCTEMP(comp_ctx);
				duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, dest, x->regconst);
				return dest;
			}
			return x->regconst;
		}

		DUK_ASSERT(forced_reg < 0 && !DUK__ISCONST(x->regconst));
		if ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) && !DUK__ISREG_TEMP(comp_ctx, x->regconst)) {
			duk_regconst_t dest = DUK__ALLOCTEMP(comp_ctx);
			duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, dest, x->regconst);
			return dest;
		}
		return x->regconst;
	}
	default: {
		break;  /* never here */
	}
	}

 fail_internal:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return 0;);
}

DUK_LOCAL void duk__ispec_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ispec *x, duk_regconst_t forced_reg) {
	DUK_ASSERT(forced_reg >= 0);
	(void) duk__ispec_toregconst_raw(comp_ctx, x, forced_reg, 0 /*flags*/);
}

/* Coerce an duk_ivalue to a 'plain' value by generating the necessary
 * arithmetic operations, property access, or variable access bytecode.
 * The duk_ivalue argument ('x') is converted into a plain value as a
 * side effect.
 */
DUK_LOCAL void duk__ivalue_toplain_raw(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_regconst_t forced_reg) {
	duk_hthread *thr = comp_ctx->thr;

	DUK_DDD(DUK_DDDPRINT("duk__ivalue_toplain_raw(): x={t=%ld,op=%ld,x1={%ld:%ld:%!T},x2={%ld:%ld:%!T}}, "
	                     "forced_reg=%ld",
	                     (long) x->t, (long) x->op,
	                     (long) x->x1.t, (long) x->x1.regconst,
	                     (duk_tval *) duk_get_tval(thr, x->x1.valstack_idx),
	                     (long) x->x2.t, (long) x->x2.regconst,
	                     (duk_tval *) duk_get_tval(thr, x->x2.valstack_idx),
	                     (long) forced_reg));

	switch (x->t) {
	case DUK_IVAL_PLAIN: {
		return;
	}
	/* XXX: support unary arithmetic ivalues (useful?) */
	case DUK_IVAL_ARITH: {
		duk_regconst_t arg1;
		duk_regconst_t arg2;
		duk_regconst_t dest;
		duk_tval *tv1;
		duk_tval *tv2;

		DUK_DDD(DUK_DDDPRINT("arith to plain conversion"));

		/* inline arithmetic check for constant values */
		/* XXX: use the exactly same arithmetic function here as in executor */
		if (x->x1.t == DUK_ISPEC_VALUE && x->x2.t == DUK_ISPEC_VALUE && x->t == DUK_IVAL_ARITH) {
			tv1 = DUK_GET_TVAL_POSIDX(thr, x->x1.valstack_idx);
			tv2 = DUK_GET_TVAL_POSIDX(thr, x->x2.valstack_idx);
			DUK_ASSERT(tv1 != NULL);
			DUK_ASSERT(tv2 != NULL);

			DUK_DDD(DUK_DDDPRINT("arith: tv1=%!T, tv2=%!T",
			                     (duk_tval *) tv1,
			                     (duk_tval *) tv2));

			if (DUK_TVAL_IS_NUMBER(tv1) && DUK_TVAL_IS_NUMBER(tv2)) {
				duk_double_t d1 = DUK_TVAL_GET_NUMBER(tv1);
				duk_double_t d2 = DUK_TVAL_GET_NUMBER(tv2);
				duk_double_t d3;
				duk_bool_t accept_fold = 1;

				DUK_DDD(DUK_DDDPRINT("arith inline check: d1=%lf, d2=%lf, op=%ld",
				                     (double) d1, (double) d2, (long) x->op));
				switch (x->op) {
				case DUK_OP_ADD: {
					d3 = d1 + d2;
					break;
				}
				case DUK_OP_SUB: {
					d3 = d1 - d2;
					break;
				}
				case DUK_OP_MUL: {
					d3 = d1 * d2;
					break;
				}
				case DUK_OP_DIV: {
					/* Division-by-zero is undefined
					 * behavior, so rely on a helper.
					 */
					d3 = duk_double_div(d1, d2);
					break;
				}
				case DUK_OP_EXP: {
					d3 = (duk_double_t) duk_js_arith_pow((double) d1, (double) d2);
					break;
				}
				default: {
					d3 = 0.0;  /* Won't be used, but silence MSVC /W4 warning. */
					accept_fold = 0;
					break;
				}
				}

				if (accept_fold) {
					duk_double_union du;
					du.d = d3;
					DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
					d3 = du.d;

					x->t = DUK_IVAL_PLAIN;
					DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);
					DUK_TVAL_SET_NUMBER(tv1, d3);  /* old value is number: no refcount */
					return;
				}
			} else if (x->op == DUK_OP_ADD && DUK_TVAL_IS_STRING(tv1) && DUK_TVAL_IS_STRING(tv2)) {
				/* Inline string concatenation.  No need to check for
				 * symbols, as all inputs are valid ECMAScript strings.
				 */
				duk_dup(thr, x->x1.valstack_idx);
				duk_dup(thr, x->x2.valstack_idx);
				duk_concat(thr, 2);
				duk_replace(thr, x->x1.valstack_idx);
				x->t = DUK_IVAL_PLAIN;
				DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);
				return;
			}
		}

		arg1 = duk__ispec_toregconst_raw(comp_ctx, &x->x1, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);
		arg2 = duk__ispec_toregconst_raw(comp_ctx, &x->x2, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);

		/* If forced reg, use it as destination.  Otherwise try to
		 * use either coerced ispec if it is a temporary.
		 */
		if (forced_reg >= 0) {
			dest = forced_reg;
		} else if (DUK__ISREG_TEMP(comp_ctx, arg1)) {
			dest = arg1;
		} else if (DUK__ISREG_TEMP(comp_ctx, arg2)) {
			dest = arg2;
		} else {
			dest = DUK__ALLOCTEMP(comp_ctx);
		}

		DUK_ASSERT(DUK__ISREG(dest));
		duk__emit_a_b_c(comp_ctx, x->op | DUK__EMIT_FLAG_BC_REGCONST, dest, arg1, arg2);

		duk__ivalue_regconst(x, dest);
		return;
	}
	case DUK_IVAL_PROP: {
		/* XXX: very similar to DUK_IVAL_ARITH - merge? */
		duk_regconst_t arg1;
		duk_regconst_t arg2;
		duk_regconst_t dest;

		/* Need a short reg/const, does not have to be a mutable temp. */
		arg1 = duk__ispec_toregconst_raw(comp_ctx, &x->x1, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);
		arg2 = duk__ispec_toregconst_raw(comp_ctx, &x->x2, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);

		/* Pick a destination register.  If either base value or key
		 * happens to be a temp value, reuse it as the destination.
		 *
		 * XXX: The temp must be a "mutable" one, i.e. such that no
		 * other expression is using it anymore.  Here this should be
		 * the case because the value of a property access expression
		 * is neither the base nor the key, but the lookup result.
		 */

		if (forced_reg >= 0) {
			dest = forced_reg;
		} else if (DUK__ISREG_TEMP(comp_ctx, arg1)) {
			dest = arg1;
		} else if (DUK__ISREG_TEMP(comp_ctx, arg2)) {
			dest = arg2;
		} else {
			dest = DUK__ALLOCTEMP(comp_ctx);
		}

		duk__emit_a_b_c(comp_ctx,
		                DUK_OP_GETPROP | DUK__EMIT_FLAG_BC_REGCONST,
		                dest,
		                arg1,
		                arg2);

		duk__ivalue_regconst(x, dest);
		return;
	}
	case DUK_IVAL_VAR: {
		/* x1 must be a string */
		duk_regconst_t dest;
		duk_regconst_t reg_varbind;
		duk_regconst_t rc_varname;

		DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);

		duk_dup(thr, x->x1.valstack_idx);
		if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
			duk__ivalue_regconst(x, reg_varbind);
		} else {
			dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
			duk__emit_a_bc(comp_ctx, DUK_OP_GETVAR, dest, rc_varname);
			duk__ivalue_regconst(x, dest);
		}
		return;
	}
	case DUK_IVAL_NONE:
	default: {
		DUK_D(DUK_DPRINT("invalid ivalue type: %ld", (long) x->t));
		break;
	}
	}

	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return;);
}

/* evaluate to plain value, no forced register (temp/bound reg both ok) */
DUK_LOCAL void duk__ivalue_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	duk__ivalue_toplain_raw(comp_ctx, x, -1 /*forced_reg*/);
}

/* evaluate to final form (e.g. coerce GETPROP to code), throw away temp */
DUK_LOCAL void duk__ivalue_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	duk_regconst_t temp;

	/* If duk__ivalue_toplain_raw() allocates a temp, forget it and
	 * restore next temp state.
	 */
	temp = DUK__GETTEMP(comp_ctx);
	duk__ivalue_toplain_raw(comp_ctx, x, -1 /*forced_reg*/);
	DUK__SETTEMP(comp_ctx, temp);
}

/* Coerce an duk_ivalue to a register or constant; result register may
 * be a temp or a bound register.
 *
 * The duk_ivalue argument ('x') is converted into a regconst as a
 * side effect.
 */
DUK_LOCAL
duk_regconst_t duk__ivalue_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                          duk_ivalue *x,
                                          duk_regconst_t forced_reg,
                                          duk_small_uint_t flags) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t reg;
	DUK_UNREF(thr);

	DUK_DDD(DUK_DDDPRINT("duk__ivalue_toregconst_raw(): x={t=%ld,op=%ld,x1={%ld:%ld:%!T},x2={%ld:%ld:%!T}}, "
	                     "forced_reg=%ld, flags 0x%08lx: allow_const=%ld require_temp=%ld require_short=%ld",
	                     (long) x->t, (long) x->op,
	                     (long) x->x1.t, (long) x->x1.regconst,
	                     (duk_tval *) duk_get_tval(thr, x->x1.valstack_idx),
	                     (long) x->x2.t, (long) x->x2.regconst,
	                     (duk_tval *) duk_get_tval(thr, x->x2.valstack_idx),
	                     (long) forced_reg,
	                     (unsigned long) flags,
	                     (long) ((flags & DUK__IVAL_FLAG_ALLOW_CONST) ? 1 : 0),
	                     (long) ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) ? 1 : 0),
	                     (long) ((flags & DUK__IVAL_FLAG_REQUIRE_SHORT) ? 1 : 0)));

	/* first coerce to a plain value */
	duk__ivalue_toplain_raw(comp_ctx, x, forced_reg);
	DUK_ASSERT(x->t == DUK_IVAL_PLAIN);

	/* then to a register */
	reg = duk__ispec_toregconst_raw(comp_ctx, &x->x1, forced_reg, flags);
	duk__ivalue_regconst(x, reg);

	return reg;
}

DUK_LOCAL duk_regconst_t duk__ivalue_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	return duk__ivalue_toregconst_raw(comp_ctx, x, -1, 0 /*flags*/);
}

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__ivalue_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);
}
#endif

DUK_LOCAL void duk__ivalue_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_int_t forced_reg) {
	DUK_ASSERT(forced_reg >= 0);
	(void) duk__ivalue_toregconst_raw(comp_ctx, x, forced_reg, 0 /*flags*/);
}

DUK_LOCAL duk_regconst_t duk__ivalue_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
}

DUK_LOCAL duk_regconst_t duk__ivalue_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
	return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);
}

/* The issues below can be solved with better flags */

/* XXX: many operations actually want toforcedtemp() -- brand new temp? */
/* XXX: need a toplain_ignore() which will only coerce a value to a temp
 * register if it might have a side effect.  Side-effect free values do not
 * need to be coerced.
 */

/*
 *  Identifier handling
 */

DUK_LOCAL duk_regconst_t duk__lookup_active_register_binding(duk_compiler_ctx *comp_ctx) {
	duk_hthread *thr = comp_ctx->thr;
	duk_hstring *h_varname;
	duk_regconst_t ret;

	DUK_DDD(DUK_DDDPRINT("resolving identifier reference to '%!T'",
	                     (duk_tval *) duk_get_tval(thr, -1)));

	/*
	 *  Special name handling
	 */

	h_varname = duk_known_hstring(thr, -1);

	if (h_varname == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)) {
		DUK_DDD(DUK_DDDPRINT("flagging function as accessing 'arguments'"));
		comp_ctx->curr_func.id_access_arguments = 1;
	}

	/*
	 *  Inside one or more 'with' statements fall back to slow path always.
	 *  (See e.g. test-stmt-with.js.)
	 */

	if (comp_ctx->curr_func.with_depth > 0) {
		DUK_DDD(DUK_DDDPRINT("identifier lookup inside a 'with' -> fall back to slow path"));
		goto slow_path_own;
	}

	/*
	 *  Any catch bindings ("catch (e)") also affect identifier binding.
	 *
	 *  Currently, the varmap is modified for the duration of the catch
	 *  clause to ensure any identifier accesses with the catch variable
	 *  name will use slow path.
	 */

	duk_get_prop(thr, comp_ctx->curr_func.varmap_idx);
	if (duk_is_number(thr, -1)) {
		ret = duk_to_int(thr, -1);
		duk_pop(thr);
	} else {
		duk_pop(thr);
		if (comp_ctx->curr_func.catch_depth > 0 || comp_ctx->curr_func.with_depth > 0) {
			DUK_DDD(DUK_DDDPRINT("slow path access from inside a try-catch or with needs _Varmap"));
			goto slow_path_own;
		} else {
			/* In this case we're doing a variable lookup that doesn't
			 * match our own variables, so _Varmap won't be needed at
			 * run time.
			 */
			DUK_DDD(DUK_DDDPRINT("slow path access outside of try-catch and with, no need for _Varmap"));
			goto slow_path_notown;
		}
	}

	DUK_DDD(DUK_DDDPRINT("identifier lookup -> reg %ld", (long) ret));
	return ret;

 slow_path_notown:
	DUK_DDD(DUK_DDDPRINT("identifier lookup -> slow path, not own variable"));

	comp_ctx->curr_func.id_access_slow = 1;
	return (duk_regconst_t) -1;

 slow_path_own:
	DUK_DDD(DUK_DDDPRINT("identifier lookup -> slow path, may be own variable"));

	comp_ctx->curr_func.id_access_slow = 1;
	comp_ctx->curr_func.id_access_slow_own = 1;
	return (duk_regconst_t) -1;
}

/* Lookup an identifier name in the current varmap, indicating whether the
 * identifier is register-bound and if not, allocating a constant for the
 * identifier name.  Returns 1 if register-bound, 0 otherwise.  Caller can
 * also check (out_reg_varbind >= 0) to check whether or not identifier is
 * register bound.  The caller must NOT use out_rc_varname at all unless
 * return code is 0 or out_reg_varbind is < 0; this is becuase out_rc_varname
 * is unsigned and doesn't have a "unused" / none value.
 */
DUK_LOCAL duk_bool_t duk__lookup_lhs(duk_compiler_ctx *comp_ctx, duk_regconst_t *out_reg_varbind, duk_regconst_t *out_rc_varname) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t reg_varbind;
	duk_regconst_t rc_varname;

	/* [ ... varname ] */

	duk_dup_top(thr);
	reg_varbind = duk__lookup_active_register_binding(comp_ctx);

	if (reg_varbind >= 0) {
		*out_reg_varbind = reg_varbind;
		*out_rc_varname = 0;  /* duk_regconst_t is unsigned, so use 0 as dummy value (ignored by caller) */
		duk_pop(thr);
		return 1;
	} else {
		rc_varname = duk__getconst(comp_ctx);
		*out_reg_varbind = -1;
		*out_rc_varname = rc_varname;
		return 0;
	}
}

/*
 *  Label handling
 *
 *  Labels are initially added with flags prohibiting both break and continue.
 *  When the statement type is finally uncovered (after potentially multiple
 *  labels), all the labels are updated to allow/prohibit break and continue.
 */

DUK_LOCAL void duk__add_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_int_t pc_label, duk_int_t label_id) {
	duk_hthread *thr = comp_ctx->thr;
	duk_size_t n;
	duk_size_t new_size;
	duk_uint8_t *p;
	duk_labelinfo *li_start, *li;

	/* Duplicate (shadowing) labels are not allowed, except for the empty
	 * labels (which are used as default labels for switch and iteration
	 * statements).
	 *
	 * We could also allow shadowing of non-empty pending labels without any
	 * other issues than breaking the required label shadowing requirements
	 * of the E5 specification, see Section 12.12.
	 */

	p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
	li_start = (duk_labelinfo *) (void *) p;
	li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
	n = (duk_size_t) (li - li_start);

	while (li > li_start) {
		li--;

		if (li->h_label == h_label && h_label != DUK_HTHREAD_STRING_EMPTY_STRING(thr)) {
			DUK_ERROR_SYNTAX(thr, DUK_STR_DUPLICATE_LABEL);
			DUK_WO_NORETURN(return;);
		}
	}

	duk_push_hstring(thr, h_label);
	DUK_ASSERT(n <= DUK_UARRIDX_MAX);  /* label limits */
	(void) duk_put_prop_index(thr, comp_ctx->curr_func.labelnames_idx, (duk_uarridx_t) n);

	new_size = (n + 1) * sizeof(duk_labelinfo);
	duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, new_size);
	/* XXX: slack handling, slow now */

	/* relookup after possible realloc */
	p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
	li_start = (duk_labelinfo *) (void *) p;
	DUK_UNREF(li_start);  /* silence scan-build warning */
	li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
	li--;

	/* Labels can be used for iteration statements but also for other statements,
	 * in particular a label can be used for a block statement.  All cases of a
	 * named label accept a 'break' so that flag is set here.  Iteration statements
	 * also allow 'continue', so that flag is updated when we figure out the
	 * statement type.
	 */

	li->flags = DUK_LABEL_FLAG_ALLOW_BREAK;
	li->label_id = label_id;
	li->h_label = h_label;
	li->catch_depth = comp_ctx->curr_func.catch_depth;   /* catch depth from current func */
	li->pc_label = pc_label;

	DUK_DDD(DUK_DDDPRINT("registered label: flags=0x%08lx, id=%ld, name=%!O, catch_depth=%ld, pc_label=%ld",
	                     (unsigned long) li->flags, (long) li->label_id, (duk_heaphdr *) li->h_label,
	                     (long) li->catch_depth, (long) li->pc_label));
}

/* Update all labels with matching label_id. */
DUK_LOCAL void duk__update_label_flags(duk_compiler_ctx *comp_ctx, duk_int_t label_id, duk_small_uint_t flags) {
	duk_uint8_t *p;
	duk_labelinfo *li_start, *li;

	p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(comp_ctx->thr->heap, comp_ctx->curr_func.h_labelinfos);
	li_start = (duk_labelinfo *) (void *) p;
	li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));

	/* Match labels starting from latest; once label_id no longer matches, we can
	 * safely exit without checking the rest of the labels (only the topmost labels
	 * are ever updated).
	 */
	while (li > li_start) {
		li--;

		if (li->label_id != label_id) {
			break;
		}

		DUK_DDD(DUK_DDDPRINT("updating (overwriting) label flags for li=%p, label_id=%ld, flags=%ld",
		                     (void *) li, (long) label_id, (long) flags));

		li->flags = flags;
	}
}

/* Lookup active label information.  Break/continue distinction is necessary to handle switch
 * statement related labels correctly: a switch will only catch a 'break', not a 'continue'.
 *
 * An explicit label cannot appear multiple times in the active set, but empty labels (unlabelled
 * iteration and switch statements) can.  A break will match the closest unlabelled or labelled
 * statement.  A continue will match the closest unlabelled or labelled iteration statement.  It is
 * a syntax error if a continue matches a labelled switch statement; because an explicit label cannot
 * be duplicated, the continue cannot match any valid label outside the switch.
 *
 * A side effect of these rules is that a LABEL statement related to a switch should never actually
 * catch a continue abrupt completion at run-time.  Hence an INVALID opcode can be placed in the
 * continue slot of the switch's LABEL statement.
 */

/* XXX: awkward, especially the bunch of separate output values -> output struct? */
DUK_LOCAL void duk__lookup_active_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_bool_t is_break, duk_int_t *out_label_id, duk_int_t *out_label_catch_depth, duk_int_t *out_label_pc, duk_bool_t *out_is_closest) {
	duk_hthread *thr = comp_ctx->thr;
	duk_uint8_t *p;
	duk_labelinfo *li_start, *li_end, *li;
	duk_bool_t match = 0;

	DUK_DDD(DUK_DDDPRINT("looking up active label: label='%!O', is_break=%ld",
	                     (duk_heaphdr *) h_label, (long) is_break));

	DUK_UNREF(thr);

	p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
	li_start = (duk_labelinfo *) (void *) p;
	li_end = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
	li = li_end;

	/* Match labels starting from latest label because there can be duplicate empty
	 * labels in the label set.
	 */
	while (li > li_start) {
		li--;

		if (li->h_label != h_label) {
			DUK_DDD(DUK_DDDPRINT("labelinfo[%ld] ->'%!O' != %!O",
			                     (long) (li - li_start),
			                     (duk_heaphdr *) li->h_label,
			                     (duk_heaphdr *) h_label));
			continue;
		}

		DUK_DDD(DUK_DDDPRINT("labelinfo[%ld] -> '%!O' label name matches (still need to check type)",
		                     (long) (li - li_start), (duk_heaphdr *) h_label));

		/* currently all labels accept a break, so no explicit check for it now */
		DUK_ASSERT(li->flags & DUK_LABEL_FLAG_ALLOW_BREAK);

		if (is_break) {
			/* break matches always */
			match = 1;
			break;
		} else if (li->flags & DUK_LABEL_FLAG_ALLOW_CONTINUE) {
			/* iteration statements allow continue */
			match = 1;
			break;
		} else {
			/* continue matched this label -- we can only continue if this is the empty
			 * label, for which duplication is allowed, and thus there is hope of
			 * finding a match deeper in the label stack.
			 */
			if (h_label != DUK_HTHREAD_STRING_EMPTY_STRING(thr)) {
				DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LABEL);
				DUK_WO_NORETURN(return;);
			} else {
				DUK_DDD(DUK_DDDPRINT("continue matched an empty label which does not "
				                     "allow a continue -> continue lookup deeper in label stack"));
			}
		}
	}
	/* XXX: match flag is awkward, rework */
	if (!match) {
		DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LABEL);
		DUK_WO_NORETURN(return;);
	}

	DUK_DDD(DUK_DDDPRINT("label match: %!O -> label_id %ld, catch_depth=%ld, pc_label=%ld",
	                     (duk_heaphdr *) h_label, (long) li->label_id,
	                     (long) li->catch_depth, (long) li->pc_label));

	*out_label_id = li->label_id;
	*out_label_catch_depth = li->catch_depth;
	*out_label_pc = li->pc_label;
	*out_is_closest = (li == li_end - 1);
}

DUK_LOCAL void duk__reset_labels_to_length(duk_compiler_ctx *comp_ctx, duk_size_t len) {
	duk_hthread *thr = comp_ctx->thr;

	duk_set_length(thr, comp_ctx->curr_func.labelnames_idx, len);
	duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, sizeof(duk_labelinfo) * len);
}

/*
 *  Expression parsing: duk__expr_nud(), duk__expr_led(), duk__expr_lbp(), and helpers.
 *
 *  - duk__expr_nud(): ("null denotation"): process prev_token as a "start" of an expression (e.g. literal)
 *  - duk__expr_led(): ("left denotation"): process prev_token in the "middle" of an expression (e.g. operator)
 *  - duk__expr_lbp(): ("left-binding power"): return left-binding power of curr_token
 */

/* object literal key tracking flags */
#define DUK__OBJ_LIT_KEY_PLAIN  (1 << 0)  /* key encountered as a plain property */
#define DUK__OBJ_LIT_KEY_GET    (1 << 1)  /* key encountered as a getter */
#define DUK__OBJ_LIT_KEY_SET    (1 << 2)  /* key encountered as a setter */

DUK_LOCAL void duk__nud_array_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t reg_obj;                 /* result reg */
	duk_regconst_t reg_temp;                /* temp reg */
	duk_regconst_t temp_start;              /* temp reg value for start of loop */
	duk_small_uint_t max_init_values;  /* max # of values initialized in one MPUTARR set */
	duk_small_uint_t num_values;       /* number of values in current MPUTARR set */
	duk_uarridx_t curr_idx;            /* current (next) array index */
	duk_uarridx_t start_idx;           /* start array index of current MPUTARR set */
	duk_uarridx_t init_idx;            /* last array index explicitly initialized, +1 */
	duk_bool_t require_comma;          /* next loop requires a comma */
#if !defined(DUK_USE_PREFER_SIZE)
	duk_int_t pc_newarr;
	duk_compiler_instr *instr;
#endif

	/* DUK_TOK_LBRACKET already eaten, current token is right after that */
	DUK_ASSERT(comp_ctx->prev_token.t == DUK_TOK_LBRACKET);

	max_init_values = DUK__MAX_ARRAY_INIT_VALUES;  /* XXX: depend on available temps? */

	reg_obj = DUK__ALLOCTEMP(comp_ctx);
#if !defined(DUK_USE_PREFER_SIZE)
	pc_newarr = duk__get_current_pc(comp_ctx);
#endif
	duk__emit_bc(comp_ctx, DUK_OP_NEWARR, reg_obj);  /* XXX: patch initial size hint afterwards? */
	temp_start = DUK__GETTEMP(comp_ctx);

	/*
	 *  Emit initializers in sets of maximum max_init_values.
	 *  Corner cases such as single value initializers do not have
	 *  special handling now.
	 *
	 *  Elided elements must not be emitted as 'undefined' values,
	 *  because such values would be enumerable (which is incorrect).
	 *  Also note that trailing elisions must be reflected in the
	 *  length of the final array but cause no elements to be actually
	 *  inserted.
	 */

	curr_idx = 0;
	init_idx = 0;         /* tracks maximum initialized index + 1 */
	start_idx = 0;
	require_comma = 0;

	for (;;) {
		num_values = 0;
		DUK__SETTEMP(comp_ctx, temp_start);

		if (comp_ctx->curr_token.t == DUK_TOK_RBRACKET) {
			break;
		}

		for (;;) {
			if (comp_ctx->curr_token.t == DUK_TOK_RBRACKET) {
				/* the outer loop will recheck and exit */
				break;
			}

			/* comma check */
			if (require_comma) {
				if (comp_ctx->curr_token.t == DUK_TOK_COMMA) {
					/* comma after a value, expected */
					duk__advance(comp_ctx);
					require_comma = 0;
					continue;
				} else {
					goto syntax_error;
				}
			} else {
				if (comp_ctx->curr_token.t == DUK_TOK_COMMA) {
					/* elision - flush */
					curr_idx++;
					duk__advance(comp_ctx);
					/* if num_values > 0, MPUTARR emitted by outer loop after break */
					break;
				}
			}
			/* else an array initializer element */

			/* initial index */
			if (num_values == 0) {
				start_idx = curr_idx;
				reg_temp = DUK__ALLOCTEMP(comp_ctx);
				duk__emit_load_int32(comp_ctx, reg_temp, (duk_int32_t) start_idx);
			}

			reg_temp = DUK__ALLOCTEMP(comp_ctx);   /* alloc temp just in case, to update max temp */
			DUK__SETTEMP(comp_ctx, reg_temp);
			duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);
			DUK__SETTEMP(comp_ctx, reg_temp + 1);

			num_values++;
			curr_idx++;
			require_comma = 1;

			if (num_values >= max_init_values) {
				/* MPUTARR emitted by outer loop */
				break;
			}
		}

		if (num_values > 0) {
			/* - A is a source register (it's not a write target, but used
			 *   to identify the target object) but can be shuffled.
			 * - B cannot be shuffled normally because it identifies a range
			 *   of registers, the emitter has special handling for this
			 *   (the "no shuffle" flag must not be set).
			 * - C is a non-register number and cannot be shuffled, but
			 *   never needs to be.
			 */
			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_MPUTARR |
			                    DUK__EMIT_FLAG_NO_SHUFFLE_C |
			                    DUK__EMIT_FLAG_A_IS_SOURCE,
			                reg_obj,
			                temp_start,
			                (duk_regconst_t) (num_values + 1));
			init_idx = start_idx + num_values;

			/* num_values and temp_start reset at top of outer loop */
		}
	}

	/* Update initil size for NEWARR, doesn't need to be exact and is
	 * capped at A field limit.
	 */
#if !defined(DUK_USE_PREFER_SIZE)
	instr = duk__get_instr_ptr(comp_ctx, pc_newarr);
	instr->ins |= DUK_ENC_OP_A(0, curr_idx > DUK_BC_A_MAX ? DUK_BC_A_MAX : curr_idx);
#endif

	DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RBRACKET);
	duk__advance(comp_ctx);

	DUK_DDD(DUK_DDDPRINT("array literal done, curridx=%ld, initidx=%ld",
	                     (long) curr_idx, (long) init_idx));

	/* trailing elisions? */
	if (curr_idx > init_idx) {
		/* yes, must set array length explicitly */
		DUK_DDD(DUK_DDDPRINT("array literal has trailing elisions which affect its length"));
		reg_temp = DUK__ALLOCTEMP(comp_ctx);
		duk__emit_load_int32(comp_ctx, reg_temp, (duk_int_t) curr_idx);
		duk__emit_a_bc(comp_ctx,
		               DUK_OP_SETALEN | DUK__EMIT_FLAG_A_IS_SOURCE,
		               reg_obj,
		               reg_temp);
	}

	DUK__SETTEMP(comp_ctx, temp_start);

	duk__ivalue_regconst(res, reg_obj);
	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_ARRAY_LITERAL);
	DUK_WO_NORETURN(return;);
}

typedef struct {
	duk_regconst_t reg_obj;
	duk_regconst_t temp_start;
	duk_small_uint_t num_pairs;
	duk_small_uint_t num_total_pairs;
} duk__objlit_state;

DUK_LOCAL void duk__objlit_flush_keys(duk_compiler_ctx *comp_ctx, duk__objlit_state *st) {
	if (st->num_pairs > 0) {
		/* - A is a source register (it's not a write target, but used
		 *   to identify the target object) but can be shuffled.
		 * - B cannot be shuffled normally because it identifies a range
		 *   of registers, the emitter has special handling for this
		 *   (the "no shuffle" flag must not be set).
		 * - C is a non-register number and cannot be shuffled, but
		 *   never needs to be.
		 */
		DUK_ASSERT(st->num_pairs > 0);
		duk__emit_a_b_c(comp_ctx,
		                DUK_OP_MPUTOBJ |
		                    DUK__EMIT_FLAG_NO_SHUFFLE_C |
		                    DUK__EMIT_FLAG_A_IS_SOURCE,
		                st->reg_obj,
		                st->temp_start,
		                (duk_regconst_t) (st->num_pairs * 2));
		st->num_total_pairs += st->num_pairs;
		st->num_pairs = 0;
	}
	DUK__SETTEMP(comp_ctx, st->temp_start);
}

DUK_LOCAL duk_bool_t duk__objlit_load_key(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_token *tok, duk_regconst_t reg_temp) {
	if (tok->t_nores == DUK_TOK_IDENTIFIER || tok->t_nores == DUK_TOK_STRING) {
		/* same handling for identifiers and strings */
		DUK_ASSERT(tok->str1 != NULL);
		duk_push_hstring(comp_ctx->thr, tok->str1);
	} else if (tok->t == DUK_TOK_NUMBER) {
		/* numbers can be loaded as numbers and coerced on the fly */
		duk_push_number(comp_ctx->thr, tok->num);
	} else {
		return 1;  /* error */
	}

	duk__ivalue_plain_fromstack(comp_ctx, res);
	DUK__SETTEMP(comp_ctx, reg_temp + 1);
	duk__ivalue_toforcedreg(comp_ctx, res, reg_temp);
	DUK__SETTEMP(comp_ctx, reg_temp + 1);
	return 0;
}

DUK_LOCAL void duk__nud_object_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk__objlit_state st;
	duk_regconst_t reg_temp;          /* temp reg */
	duk_small_uint_t max_init_pairs;  /* max # of key-value pairs initialized in one MPUTOBJ set */
	duk_bool_t first;                 /* first value: comma must not precede the value */
	duk_bool_t is_set, is_get;        /* temps */
#if !defined(DUK_USE_PREFER_SIZE)
	duk_int_t pc_newobj;
	duk_compiler_instr *instr;
#endif

	DUK_ASSERT(comp_ctx->prev_token.t == DUK_TOK_LCURLY);

	max_init_pairs = DUK__MAX_OBJECT_INIT_PAIRS;  /* XXX: depend on available temps? */

	st.reg_obj = DUK__ALLOCTEMP(comp_ctx);    /* target object */
	st.temp_start = DUK__GETTEMP(comp_ctx);   /* start of MPUTOBJ argument list */
	st.num_pairs = 0;                         /* number of key/value pairs emitted for current MPUTOBJ set */
	st.num_total_pairs = 0;                   /* number of key/value pairs emitted overall */

#if !defined(DUK_USE_PREFER_SIZE)
	pc_newobj = duk__get_current_pc(comp_ctx);
#endif
	duk__emit_bc(comp_ctx, DUK_OP_NEWOBJ, st.reg_obj);

	/*
	 *  Emit initializers in sets of maximum max_init_pairs keys.
	 *  Setter/getter is handled separately and terminates the
	 *  current set of initializer values.  Corner cases such as
	 *  single value initializers do not have special handling now.
	 */

	first = 1;
	for (;;) {
		/*
		 *  ES5 and ES2015+ provide a lot of different PropertyDefinition
		 *  formats, see http://www.ecma-international.org/ecma-262/6.0/#sec-object-initializer.
		 *
		 *  PropertyName can be IdentifierName (includes reserved words), a string
		 *  literal, or a number literal.  Note that IdentifierName allows 'get' and
		 *  'set' too, so we need to look ahead to the next token to distinguish:
		 *
		 *     { get : 1 }
		 *
		 *  and
		 *
		 *     { get foo() { return 1 } }
		 *     { get get() { return 1 } }    // 'get' as getter propertyname
		 *
		 *  Finally, a trailing comma is allowed.
		 *
		 *  Key name is coerced to string at compile time (and ends up as a
		 *  a string constant) even for numeric keys (e.g. "{1:'foo'}").
		 *  These could be emitted using e.g. LDINT, but that seems hardly
		 *  worth the effort and would increase code size.
		 */

		DUK_DDD(DUK_DDDPRINT("object literal loop, curr_token->t = %ld",
		                     (long) comp_ctx->curr_token.t));

		if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
			break;
		}

		if (first) {
			first = 0;
		} else {
			if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
				goto syntax_error;
			}
			duk__advance(comp_ctx);
			if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
				/* trailing comma followed by rcurly */
				break;
			}
		}

		/* Advance to get one step of lookup. */
		duk__advance(comp_ctx);

		/* Flush current MPUTOBJ if enough many pairs gathered. */
		if (st.num_pairs >= max_init_pairs) {
			duk__objlit_flush_keys(comp_ctx, &st);
			DUK_ASSERT(st.num_pairs == 0);
		}

		/* Reset temp register state and reserve reg_temp and
		 * reg_temp + 1 for handling the current property.
		 */
		DUK__SETTEMP(comp_ctx, st.temp_start + 2 * (duk_regconst_t) st.num_pairs);
		reg_temp = DUK__ALLOCTEMPS(comp_ctx, 2);

		/* NOTE: "get" and "set" are not officially ReservedWords and the lexer
		 * currently treats them always like ordinary identifiers (DUK_TOK_GET
		 * and DUK_TOK_SET are unused).  They need to be detected based on the
		 * identifier string content.
		 */

		is_get = (comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
		          comp_ctx->prev_token.str1 == DUK_HTHREAD_STRING_GET(thr));
		is_set = (comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
		          comp_ctx->prev_token.str1 == DUK_HTHREAD_STRING_SET(thr));
		if ((is_get || is_set) && comp_ctx->curr_token.t != DUK_TOK_COLON) {
			/* getter/setter */
			duk_int_t fnum;

			duk__objlit_flush_keys(comp_ctx, &st);
			DUK_ASSERT(DUK__GETTEMP(comp_ctx) == st.temp_start);  /* 2 regs are guaranteed to be allocated w.r.t. temp_max */
			reg_temp = DUK__ALLOCTEMPS(comp_ctx, 2);

			if (duk__objlit_load_key(comp_ctx, res, &comp_ctx->curr_token, reg_temp) != 0) {
				goto syntax_error;
			}

			/* curr_token = get/set name */
			fnum = duk__parse_func_like_fnum(comp_ctx, DUK__FUNC_FLAG_GETSET);

			duk__emit_a_bc(comp_ctx,
			               DUK_OP_CLOSURE,
			               st.temp_start + 1,
			               (duk_regconst_t) fnum);

			/* Slot C is used in a non-standard fashion (range of regs),
			 * emitter code has special handling for it (must not set the
			 * "no shuffle" flag).
			 */
			duk__emit_a_bc(comp_ctx,
			              (is_get ? DUK_OP_INITGET : DUK_OP_INITSET) | DUK__EMIT_FLAG_A_IS_SOURCE,
			              st.reg_obj,
			              st.temp_start);   /* temp_start+0 = key, temp_start+1 = closure */

			DUK_ASSERT(st.num_pairs == 0);  /* temp state is reset on next loop */
#if defined(DUK_USE_ES6)
		} else if (comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
		           (comp_ctx->curr_token.t == DUK_TOK_COMMA || comp_ctx->curr_token.t == DUK_TOK_RCURLY)) {
			duk_bool_t load_rc;

			load_rc = duk__objlit_load_key(comp_ctx, res, &comp_ctx->prev_token, reg_temp);
			DUK_UNREF(load_rc);
			DUK_ASSERT(load_rc == 0);  /* always succeeds because token is identifier */

			duk__ivalue_var_hstring(comp_ctx, res, comp_ctx->prev_token.str1);
			DUK_ASSERT(DUK__GETTEMP(comp_ctx) == reg_temp + 1);
			duk__ivalue_toforcedreg(comp_ctx, res, reg_temp + 1);

			st.num_pairs++;
		} else if ((comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER ||
		            comp_ctx->prev_token.t == DUK_TOK_STRING ||
		            comp_ctx->prev_token.t == DUK_TOK_NUMBER) &&
		           comp_ctx->curr_token.t == DUK_TOK_LPAREN) {
			duk_int_t fnum;

			/* Parsing-wise there's a small hickup here: the token parsing
			 * state is one step too advanced for the function parse helper
			 * compared to other cases.  The current solution is an extra
			 * flag to indicate whether function parsing should use the
			 * current or the previous token to starting parsing from.
			 */

			if (duk__objlit_load_key(comp_ctx, res, &comp_ctx->prev_token, reg_temp) != 0) {
				goto syntax_error;
			}

			fnum = duk__parse_func_like_fnum(comp_ctx, DUK__FUNC_FLAG_USE_PREVTOKEN | DUK__FUNC_FLAG_METDEF);

			duk__emit_a_bc(comp_ctx,
			               DUK_OP_CLOSURE,
			               reg_temp + 1,
			               (duk_regconst_t) fnum);

			st.num_pairs++;
#endif  /* DUK_USE_ES6 */
		} else {
#if defined(DUK_USE_ES6)
			if (comp_ctx->prev_token.t == DUK_TOK_LBRACKET) {
				/* ES2015 computed property name.  Executor ToPropertyKey()
				 * coerces the key at runtime.
				 */
				DUK__SETTEMP(comp_ctx, reg_temp);
				duk__expr_toforcedreg(comp_ctx, res, DUK__BP_FOR_EXPR, reg_temp);
				duk__advance_expect(comp_ctx, DUK_TOK_RBRACKET);

				/* XXX: If next token is '(' we're dealing with
				 * the method shorthand with a computed name,
				 * e.g. { [Symbol.for('foo')](a,b) {} }.  This
				 * form is not yet supported and causes a
				 * SyntaxError on the DUK_TOK_COLON check below.
				 */
			}
			else
#endif  /* DUK_USE_ES6 */
			{
				if (duk__objlit_load_key(comp_ctx, res, &comp_ctx->prev_token, reg_temp) != 0) {
					goto syntax_error;
				}
			}

			duk__advance_expect(comp_ctx, DUK_TOK_COLON);

			DUK__SETTEMP(comp_ctx, reg_temp + 1);
			duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp + 1 /*forced_reg*/);

			st.num_pairs++;
		}
	}  /* property loop */

	/* Flush remaining properties. */
	duk__objlit_flush_keys(comp_ctx, &st);
	DUK_ASSERT(st.num_pairs == 0);
	DUK_ASSERT(DUK__GETTEMP(comp_ctx) == st.temp_start);

	/* Update initial size for NEWOBJ.  The init size doesn't need to be
	 * exact as the purpose is just to avoid object resizes in common
	 * cases.  The size is capped to field A limit, and will be too high
	 * if the object literal contains duplicate keys (this is harmless but
	 * increases memory traffic if the object is compacted later on).
	 */
#if !defined(DUK_USE_PREFER_SIZE)
	instr = duk__get_instr_ptr(comp_ctx, pc_newobj);
	instr->ins |= DUK_ENC_OP_A(0, st.num_total_pairs > DUK_BC_A_MAX ? DUK_BC_A_MAX : st.num_total_pairs);
#endif

	DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RCURLY);
	duk__advance(comp_ctx);  /* No RegExp after object literal. */

	duk__ivalue_regconst(res, st.reg_obj);
	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_OBJECT_LITERAL);
	DUK_WO_NORETURN(return;);
}

/* Parse argument list.  Arguments are written to temps starting from
 * "next temp".  Returns number of arguments parsed.  Expects left paren
 * to be already eaten, and eats the right paren before returning.
 */
DUK_LOCAL duk_int_t duk__parse_arguments(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_int_t nargs = 0;
	duk_regconst_t reg_temp;

	/* Note: expect that caller has already eaten the left paren */

	DUK_DDD(DUK_DDDPRINT("start parsing arguments, prev_token.t=%ld, curr_token.t=%ld",
	                     (long) comp_ctx->prev_token.t, (long) comp_ctx->curr_token.t));

	for (;;) {
		if (comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
			break;
		}
		if (nargs > 0) {
			duk__advance_expect(comp_ctx, DUK_TOK_COMMA);
		}

		/* We want the argument expression value to go to "next temp"
		 * without additional moves.  That should almost always be the
		 * case, but we double check after expression parsing.
		 *
		 * This is not the cleanest possible approach.
		 */

		reg_temp = DUK__ALLOCTEMP(comp_ctx);  /* bump up "allocated" reg count, just in case */
		DUK__SETTEMP(comp_ctx, reg_temp);

		/* binding power must be high enough to NOT allow comma expressions directly */
		duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp);  /* always allow 'in', coerce to 'tr' just in case */

		DUK__SETTEMP(comp_ctx, reg_temp + 1);
		nargs++;

		DUK_DDD(DUK_DDDPRINT("argument #%ld written into reg %ld", (long) nargs, (long) reg_temp));
	}

	/* eat the right paren */
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* RegExp mode does not matter. */

	DUK_DDD(DUK_DDDPRINT("end parsing arguments"));

	return nargs;
}

DUK_LOCAL duk_bool_t duk__expr_is_empty(duk_compiler_ctx *comp_ctx) {
	/* empty expressions can be detected conveniently with nud/led counts */
	return (comp_ctx->curr_func.nud_count == 0) &&
	       (comp_ctx->curr_func.led_count == 0);
}

DUK_LOCAL void duk__expr_nud(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_token *tk;
	duk_regconst_t temp_at_entry;
	duk_small_uint_t tok;
	duk_uint32_t args;  /* temp variable to pass constants and flags to shared code */

	/*
	 *  ctx->prev_token     token to process with duk__expr_nud()
	 *  ctx->curr_token     updated by caller
	 *
	 *  Note: the token in the switch below has already been eaten.
	 */

	temp_at_entry = DUK__GETTEMP(comp_ctx);

	comp_ctx->curr_func.nud_count++;

	tk = &comp_ctx->prev_token;
	tok = tk->t;
	res->t = DUK_IVAL_NONE;

	DUK_DDD(DUK_DDDPRINT("duk__expr_nud(), prev_token.t=%ld, allow_in=%ld, paren_level=%ld",
	                     (long) tk->t, (long) comp_ctx->curr_func.allow_in, (long) comp_ctx->curr_func.paren_level));

	switch (tok) {

	/* PRIMARY EXPRESSIONS */

	case DUK_TOK_THIS: {
		duk_regconst_t reg_temp;
		reg_temp = DUK__ALLOCTEMP(comp_ctx);
		duk__emit_bc(comp_ctx,
		             DUK_OP_LDTHIS,
		             reg_temp);
		duk__ivalue_regconst(res, reg_temp);
		return;
	}
	case DUK_TOK_IDENTIFIER: {
		duk__ivalue_var_hstring(comp_ctx, res, tk->str1);
		return;
	}
	case DUK_TOK_NULL: {
		duk_push_null(thr);
		goto plain_value;
	}
	case DUK_TOK_TRUE: {
		duk_push_true(thr);
		goto plain_value;
	}
	case DUK_TOK_FALSE: {
		duk_push_false(thr);
		goto plain_value;
	}
	case DUK_TOK_NUMBER: {
		duk_push_number(thr, tk->num);
		goto plain_value;
	}
	case DUK_TOK_STRING: {
		DUK_ASSERT(tk->str1 != NULL);
		duk_push_hstring(thr, tk->str1);
		goto plain_value;
	}
	case DUK_TOK_REGEXP: {
#if defined(DUK_USE_REGEXP_SUPPORT)
		duk_regconst_t reg_temp;
		duk_regconst_t rc_re_bytecode;  /* const */
		duk_regconst_t rc_re_source;    /* const */

		DUK_ASSERT(tk->str1 != NULL);
		DUK_ASSERT(tk->str2 != NULL);

		DUK_DDD(DUK_DDDPRINT("emitting regexp op, str1=%!O, str2=%!O",
		                     (duk_heaphdr *) tk->str1,
		                     (duk_heaphdr *) tk->str2));

		reg_temp = DUK__ALLOCTEMP(comp_ctx);
		duk_push_hstring(thr, tk->str1);
		duk_push_hstring(thr, tk->str2);

		/* [ ... pattern flags ] */

		duk_regexp_compile(thr);

		/* [ ... escaped_source bytecode ] */

		rc_re_bytecode = duk__getconst(comp_ctx);
		rc_re_source = duk__getconst(comp_ctx);

		duk__emit_a_b_c(comp_ctx,
		                DUK_OP_REGEXP | DUK__EMIT_FLAG_BC_REGCONST,
		                reg_temp /*a*/,
		                rc_re_bytecode /*b*/,
		                rc_re_source /*c*/);

		duk__ivalue_regconst(res, reg_temp);
		return;
#else  /* DUK_USE_REGEXP_SUPPORT */
		goto syntax_error;
#endif  /* DUK_USE_REGEXP_SUPPORT */
	}
	case DUK_TOK_LBRACKET: {
		DUK_DDD(DUK_DDDPRINT("parsing array literal"));
		duk__nud_array_literal(comp_ctx, res);
		return;
	}
	case DUK_TOK_LCURLY: {
		DUK_DDD(DUK_DDDPRINT("parsing object literal"));
		duk__nud_object_literal(comp_ctx, res);
		return;
	}
	case DUK_TOK_LPAREN: {
		duk_bool_t prev_allow_in;

		comp_ctx->curr_func.paren_level++;
		prev_allow_in = comp_ctx->curr_func.allow_in;
		comp_ctx->curr_func.allow_in = 1; /* reset 'allow_in' for parenthesized expression */

		duk__expr(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression, terminates at a ')' */

		duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* No RegExp after parenthesized expression. */
		comp_ctx->curr_func.allow_in = prev_allow_in;
		comp_ctx->curr_func.paren_level--;
		return;
	}

	/* MEMBER/NEW/CALL EXPRESSIONS */

	case DUK_TOK_NEW: {
		/*
		 *  Parsing an expression starting with 'new' is tricky because
		 *  there are multiple possible productions deriving from
		 *  LeftHandSideExpression which begin with 'new'.
		 *
		 *  We currently resort to one-token lookahead to distinguish the
		 *  cases.  Hopefully this is correct.  The binding power must be
		 *  such that parsing ends at an LPAREN (CallExpression) but not at
		 *  a PERIOD or LBRACKET (MemberExpression).
		 *
		 *  See doc/compiler.rst for discussion on the parsing approach,
		 *  and testcases/test-dev-new.js for a bunch of documented tests.
		 */

		duk_regconst_t reg_target;
		duk_int_t nargs;

		DUK_DDD(DUK_DDDPRINT("begin parsing new expression"));

		reg_target = DUK__ALLOCTEMPS(comp_ctx, 2);

#if defined(DUK_USE_ES6)
		if (comp_ctx->curr_token.t == DUK_TOK_PERIOD) {
			/* new.target */
			DUK_DDD(DUK_DDDPRINT("new.target"));
			duk__advance(comp_ctx);
			if (comp_ctx->curr_token.t_nores != DUK_TOK_IDENTIFIER ||
			    !duk_hstring_equals_ascii_cstring(comp_ctx->curr_token.str1, "target")) {
				goto syntax_error_newtarget;
			}
			if (comp_ctx->curr_func.is_global) {
				goto syntax_error_newtarget;
			}
			duk__advance(comp_ctx);
			duk__emit_bc(comp_ctx,
			             DUK_OP_NEWTARGET,
			             reg_target);
			duk__ivalue_regconst(res, reg_target);
			return;
		}
#endif  /* DUK_USE_ES6 */

		duk__expr_toforcedreg(comp_ctx, res, DUK__BP_CALL /*rbp_flags*/, reg_target /*forced_reg*/);
		duk__emit_bc(comp_ctx, DUK_OP_NEWOBJ, reg_target + 1);  /* default instance */
		DUK__SETTEMP(comp_ctx, reg_target + 2);

		/* XXX: 'new obj.noSuch()' doesn't use GETPROPC now which
		 * makes the error message worse than for obj.noSuch().
		 */

		if (comp_ctx->curr_token.t == DUK_TOK_LPAREN) {
			/* 'new' MemberExpression Arguments */
			DUK_DDD(DUK_DDDPRINT("new expression has argument list"));
			duk__advance(comp_ctx);
			nargs = duk__parse_arguments(comp_ctx, res);  /* parse args starting from "next temp", reg_target + 1 */
			/* right paren eaten */
		} else {
			/* 'new' MemberExpression */
			DUK_DDD(DUK_DDDPRINT("new expression has no argument list"));
			nargs = 0;
		}

		duk__emit_a_bc(comp_ctx,
		              DUK_OP_CALL0 | DUK_BC_CALL_FLAG_CONSTRUCT,
		              nargs /*num_args*/,
		              reg_target /*target*/);

		DUK_DDD(DUK_DDDPRINT("end parsing new expression"));

		duk__ivalue_regconst(res, reg_target);
		return;
	}

	/* FUNCTION EXPRESSIONS */

	case DUK_TOK_FUNCTION: {
		/* Function expression.  Note that any statement beginning with 'function'
		 * is handled by the statement parser as a function declaration, or a
		 * non-standard function expression/statement (or a SyntaxError).  We only
		 * handle actual function expressions (occurring inside an expression) here.
		 *
		 * O(depth^2) parse count for inner functions is handled by recording a
		 * lexer offset on the first compilation pass, so that the function can
		 * be efficiently skipped on the second pass.  This is encapsulated into
		 * duk__parse_func_like_fnum().
		 */

		duk_regconst_t reg_temp;
		duk_int_t fnum;

		reg_temp = DUK__ALLOCTEMP(comp_ctx);

		/* curr_token follows 'function' */
		fnum = duk__parse_func_like_fnum(comp_ctx, 0 /*flags*/);
		DUK_DDD(DUK_DDDPRINT("parsed inner function -> fnum %ld", (long) fnum));

		duk__emit_a_bc(comp_ctx,
		               DUK_OP_CLOSURE,
		               reg_temp /*a*/,
		               (duk_regconst_t) fnum /*bc*/);

		duk__ivalue_regconst(res, reg_temp);
		return;
	}

	/* UNARY EXPRESSIONS */

	case DUK_TOK_DELETE: {
		/* Delete semantics are a bit tricky.  The description in E5 specification
		 * is kind of confusing, because it distinguishes between resolvability of
		 * a reference (which is only known at runtime) seemingly at compile time
		 * (= SyntaxError throwing).
		 */
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		if (res->t == DUK_IVAL_VAR) {
			/* not allowed in strict mode, regardless of whether resolves;
			 * in non-strict mode DELVAR handles both non-resolving and
			 * resolving cases (the specification description is a bit confusing).
			 */

			duk_regconst_t reg_temp;
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;

			if (comp_ctx->curr_func.is_strict) {
				DUK_ERROR_SYNTAX(thr, DUK_STR_CANNOT_DELETE_IDENTIFIER);
				DUK_WO_NORETURN(return;);
			}

			DUK__SETTEMP(comp_ctx, temp_at_entry);
			reg_temp = DUK__ALLOCTEMP(comp_ctx);

			duk_dup(thr, res->x1.valstack_idx);
			if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
				/* register bound variables are non-configurable -> always false */
				duk__emit_bc(comp_ctx,
				             DUK_OP_LDFALSE,
				             reg_temp);
			} else {
				duk_dup(thr, res->x1.valstack_idx);
				rc_varname = duk__getconst(comp_ctx);
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_DELVAR,
				               reg_temp,
				               rc_varname);
			}
			duk__ivalue_regconst(res, reg_temp);
		} else if (res->t == DUK_IVAL_PROP) {
			duk_regconst_t reg_temp;
			duk_regconst_t reg_obj;
			duk_regconst_t rc_key;

			DUK__SETTEMP(comp_ctx, temp_at_entry);
			reg_temp = DUK__ALLOCTEMP(comp_ctx);
			reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
			rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_DELPROP | DUK__EMIT_FLAG_BC_REGCONST,
			                reg_temp,
			                reg_obj,
			                rc_key);

			duk__ivalue_regconst(res, reg_temp);
		} else {
			/* non-Reference deletion is always 'true', even in strict mode */
			duk_push_true(thr);
			goto plain_value;
		}
		return;
	}
	case DUK_TOK_VOID: {
		duk__expr_toplain_ignore(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		duk_push_undefined(thr);
		goto plain_value;
	}
	case DUK_TOK_TYPEOF: {
		/* 'typeof' must handle unresolvable references without throwing
		 * a ReferenceError (E5 Section 11.4.3).  Register mapped values
		 * will never be unresolvable so special handling is only required
		 * when an identifier is a "slow path" one.
		 */
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */

		if (res->t == DUK_IVAL_VAR) {
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;
			duk_regconst_t reg_temp;

			duk_dup(thr, res->x1.valstack_idx);
			if (!duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
				DUK_DDD(DUK_DDDPRINT("typeof for an identifier name which could not be resolved "
				                     "at compile time, need to use special run-time handling"));
				reg_temp = DUK__ALLOCTEMP(comp_ctx);
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_TYPEOFID,
				               reg_temp,
				               rc_varname);
				duk__ivalue_regconst(res, reg_temp);
				return;
			}
		}

		args = DUK_OP_TYPEOF;
		goto unary;
	}
	case DUK_TOK_INCREMENT: {
		args = (DUK_OP_PREINCP << 8) + DUK_OP_PREINCR;
		goto preincdec;
	}
	case DUK_TOK_DECREMENT: {
		args = (DUK_OP_PREDECP << 8) + DUK_OP_PREDECR;
		goto preincdec;
	}
	case DUK_TOK_ADD: {
		/* unary plus */
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE &&
		    duk_is_number(thr, res->x1.valstack_idx)) {
			/* unary plus of a number is identity */
			return;
		}
		args = DUK_OP_UNP;
		goto unary;
	}
	case DUK_TOK_SUB: {
		/* unary minus */
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE &&
		    duk_is_number(thr, res->x1.valstack_idx)) {
			/* this optimization is important to handle negative literals
			 * (which are not directly provided by the lexical grammar)
			 */
			duk_tval *tv_num;
			duk_double_union du;

			tv_num = DUK_GET_TVAL_POSIDX(thr, res->x1.valstack_idx);
			DUK_ASSERT(tv_num != NULL);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_num));
			du.d = DUK_TVAL_GET_NUMBER(tv_num);
			du.d = -du.d;
			DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
			DUK_TVAL_SET_NUMBER(tv_num, du.d);
			return;
		}
		args = DUK_OP_UNM;
		goto unary;
	}
	case DUK_TOK_BNOT: {
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		args = DUK_OP_BNOT;
		goto unary;
	}
	case DUK_TOK_LNOT: {
		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE) {
			/* Very minimal inlining to handle common idioms '!0' and '!1',
			 * and also boolean arguments like '!false' and '!true'.
			 */
			duk_tval *tv_val;

			tv_val = DUK_GET_TVAL_POSIDX(thr, res->x1.valstack_idx);
			DUK_ASSERT(tv_val != NULL);
			if (DUK_TVAL_IS_NUMBER(tv_val)) {
				duk_double_t d;
				d = DUK_TVAL_GET_NUMBER(tv_val);
				if (duk_double_equals(d, 0.0)) {
					/* Matches both +0 and -0 on purpose. */
					DUK_DDD(DUK_DDDPRINT("inlined lnot: !0 -> true"));
					DUK_TVAL_SET_BOOLEAN_TRUE(tv_val);
					return;
				} else if (duk_double_equals(d, 1.0)) {
					DUK_DDD(DUK_DDDPRINT("inlined lnot: !1 -> false"));
					DUK_TVAL_SET_BOOLEAN_FALSE(tv_val);
					return;
				}
			} else if (DUK_TVAL_IS_BOOLEAN(tv_val)) {
				duk_small_uint_t v;
				v = DUK_TVAL_GET_BOOLEAN(tv_val);
				DUK_DDD(DUK_DDDPRINT("inlined lnot boolean: %ld", (long) v));
				DUK_ASSERT(v == 0 || v == 1);
				DUK_TVAL_SET_BOOLEAN(tv_val, v ^ 0x01);
				return;
			}
		}
		args = DUK_OP_LNOT;
		goto unary;
	}

	}  /* end switch */

	DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
	DUK_WO_NORETURN(return;);

 unary:
	{
		/* Unary opcodes use just the 'BC' register source because it
		 * matches current shuffle limits, and maps cleanly to 16 high
		 * bits of the opcode.
		 */

		duk_regconst_t reg_src, reg_res;

		reg_src = duk__ivalue_toregconst_raw(comp_ctx, res, -1 /*forced_reg*/, 0 /*flags*/);
		if (DUK__ISREG_TEMP(comp_ctx, reg_src)) {
			reg_res = reg_src;
		} else {
			reg_res = DUK__ALLOCTEMP(comp_ctx);
		}
		duk__emit_a_bc(comp_ctx,
		             args,
		             reg_res,
		             reg_src);
		duk__ivalue_regconst(res, reg_res);
		return;
	}

 preincdec:
	{
		/* preincrement and predecrement */
		duk_regconst_t reg_res;
		duk_small_uint_t args_op1 = args & 0xff;  /* DUK_OP_PREINCR/DUK_OP_PREDECR */
		duk_small_uint_t args_op2 = args >> 8;    /* DUK_OP_PREINCP_RR/DUK_OP_PREDECP_RR */

		/* Specific assumptions for opcode numbering. */
		DUK_ASSERT(DUK_OP_PREINCR + 4 == DUK_OP_PREINCV);
		DUK_ASSERT(DUK_OP_PREDECR + 4 == DUK_OP_PREDECV);

		reg_res = DUK__ALLOCTEMP(comp_ctx);

		duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
		if (res->t == DUK_IVAL_VAR) {
			duk_hstring *h_varname;
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;

			h_varname = duk_known_hstring(thr, res->x1.valstack_idx);

			if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
				goto syntax_error;
			}

			duk_dup(thr, res->x1.valstack_idx);
			if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
				duk__emit_a_bc(comp_ctx,
				               args_op1,  /* e.g. DUK_OP_PREINCR */
				               reg_res,
				               reg_varbind);
			} else {
				duk__emit_a_bc(comp_ctx,
				                args_op1 + 4,  /* e.g. DUK_OP_PREINCV */
				                reg_res,
				                rc_varname);
			}

			DUK_DDD(DUK_DDDPRINT("preincdec to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
			                     (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));
		} else if (res->t == DUK_IVAL_PROP) {
			duk_regconst_t reg_obj;  /* allocate to reg only (not const) */
			duk_regconst_t rc_key;
			reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
			rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
			duk__emit_a_b_c(comp_ctx,
			                args_op2 | DUK__EMIT_FLAG_BC_REGCONST,  /* e.g. DUK_OP_PREINCP */
			                reg_res,
			                reg_obj,
			                rc_key);
		} else {
			/* Technically return value is not needed because INVLHS will
			 * unconditially throw a ReferenceError.  Coercion is necessary
			 * for proper semantics (consider ToNumber() called for an object).
			 * Use DUK_OP_UNP with a dummy register to get ToNumber().
			 */

			duk__ivalue_toforcedreg(comp_ctx, res, reg_res);
			duk__emit_bc(comp_ctx,
			             DUK_OP_UNP,
			             reg_res);  /* for side effects, result ignored */
			duk__emit_op_only(comp_ctx,
			                  DUK_OP_INVLHS);
		}
		DUK__SETTEMP(comp_ctx, reg_res + 1);
		duk__ivalue_regconst(res, reg_res);
		return;
	}

 plain_value:
	{
		/* Stack top contains plain value */
		duk__ivalue_plain_fromstack(comp_ctx, res);
		return;
	}

#if defined(DUK_USE_ES6)
 syntax_error_newtarget:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_NEWTARGET);
	DUK_WO_NORETURN(return;);
#endif

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_EXPRESSION);
	DUK_WO_NORETURN(return;);
}

/* XXX: add flag to indicate whether caller cares about return value; this
 * affects e.g. handling of assignment expressions.  This change needs API
 * changes elsewhere too.
 */
DUK_LOCAL void duk__expr_led(duk_compiler_ctx *comp_ctx, duk_ivalue *left, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_token *tk;
	duk_small_uint_t tok;
	duk_uint32_t args;  /* temp variable to pass constants and flags to shared code */

	/*
	 *  ctx->prev_token     token to process with duk__expr_led()
	 *  ctx->curr_token     updated by caller
	 */

	comp_ctx->curr_func.led_count++;

	/* The token in the switch has already been eaten here */
	tk = &comp_ctx->prev_token;
	tok = tk->t;

	DUK_DDD(DUK_DDDPRINT("duk__expr_led(), prev_token.t=%ld, allow_in=%ld, paren_level=%ld",
	                     (long) tk->t, (long) comp_ctx->curr_func.allow_in, (long) comp_ctx->curr_func.paren_level));

	/* XXX: default priority for infix operators is duk__expr_lbp(tok) -> get it here? */

	switch (tok) {

	/* PRIMARY EXPRESSIONS */

	case DUK_TOK_PERIOD: {
		/* Property access expressions are critical for correct LHS ordering,
		 * see comments in duk__expr()!
		 *
		 * A conservative approach would be to use duk__ivalue_totempconst()
		 * for 'left'.  However, allowing a reg-bound variable seems safe here
		 * and is nice because "foo.bar" is a common expression.  If the ivalue
		 * is used in an expression a GETPROP will occur before any changes to
		 * the base value can occur.  If the ivalue is used as an assignment
		 * LHS, the assignment code will ensure the base value is safe from
		 * RHS mutation.
		 */

		/* XXX: This now coerces an identifier into a GETVAR to a temp, which
		 * causes an extra LDREG in call setup.  It's sufficient to coerce to a
		 * unary ivalue?
		 */
		duk__ivalue_toplain(comp_ctx, left);

		/* NB: must accept reserved words as property name */
		if (comp_ctx->curr_token.t_nores != DUK_TOK_IDENTIFIER) {
			DUK_ERROR_SYNTAX(thr, DUK_STR_EXPECTED_IDENTIFIER);
			DUK_WO_NORETURN(return;);
		}

		res->t = DUK_IVAL_PROP;
		duk__copy_ispec(comp_ctx, &left->x1, &res->x1);  /* left.x1 -> res.x1 */
		DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
		duk_push_hstring(thr, comp_ctx->curr_token.str1);
		duk_replace(thr, res->x2.valstack_idx);
		res->x2.t = DUK_ISPEC_VALUE;

		/* special RegExp literal handling after IdentifierName */
		comp_ctx->curr_func.reject_regexp_in_adv = 1;

		duk__advance(comp_ctx);
		return;
	}
	case DUK_TOK_LBRACKET: {
		/* Property access expressions are critical for correct LHS ordering,
		 * see comments in duk__expr()!
		 */

		/* XXX: optimize temp reg use */
		/* XXX: similar coercion issue as in DUK_TOK_PERIOD */
		/* XXX: coerce to regs? it might be better for enumeration use, where the
		 * same PROP ivalue is used multiple times.  Or perhaps coerce PROP further
		 * there?
		 */
		/* XXX: for simple cases like x['y'] an unnecessary LDREG is
		 * emitted for the base value; could avoid it if we knew that
		 * the key expression is safe (e.g. just a single literal).
		 */

		/* The 'left' value must not be a register bound variable
		 * because it may be mutated during the rest of the expression
		 * and E5.1 Section 11.2.1 specifies the order of evaluation
		 * so that the base value is evaluated first.
		 * See: test-bug-nested-prop-mutate.js.
		 */
		duk__ivalue_totempconst(comp_ctx, left);
		duk__expr_toplain(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression, ']' terminates */
		duk__advance_expect(comp_ctx, DUK_TOK_RBRACKET);

		res->t = DUK_IVAL_PROP;
		duk__copy_ispec(comp_ctx, &res->x1, &res->x2);   /* res.x1 -> res.x2 */
		duk__copy_ispec(comp_ctx, &left->x1, &res->x1);  /* left.x1 -> res.x1 */
		return;
	}
	case DUK_TOK_LPAREN: {
		/* function call */
		duk_regconst_t reg_cs = DUK__ALLOCTEMPS(comp_ctx, 2);
		duk_int_t nargs;
		duk_small_uint_t call_op = DUK_OP_CALL0;

		/* XXX: attempt to get the call result to "next temp" whenever
		 * possible to avoid unnecessary register shuffles.
		 */

		/*
		 *  Setup call: target and 'this' binding.  Three cases:
		 *
		 *    1. Identifier base (e.g. "foo()")
		 *    2. Property base (e.g. "foo.bar()")
		 *    3. Register base (e.g. "foo()()"; i.e. when a return value is a function)
		 */

		if (left->t == DUK_IVAL_VAR) {
			duk_hstring *h_varname;
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;

			DUK_DDD(DUK_DDDPRINT("function call with identifier base"));

			h_varname = duk_known_hstring(thr, left->x1.valstack_idx);
			if (h_varname == DUK_HTHREAD_STRING_EVAL(thr)) {
				/* Potential direct eval call detected, flag the CALL
				 * so that a run-time "direct eval" check is made and
				 * special behavior may be triggered.  Note that this
				 * does not prevent 'eval' from being register bound.
				 */
				DUK_DDD(DUK_DDDPRINT("function call with identifier 'eval' "
				                     "-> using EVALCALL, marking function "
				                     "as may_direct_eval"));
				call_op |= DUK_BC_CALL_FLAG_CALLED_AS_EVAL;
				comp_ctx->curr_func.may_direct_eval = 1;
			}

			duk_dup(thr, left->x1.valstack_idx);
			if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
				duk__emit_a_bc(comp_ctx,
				              DUK_OP_CSREG | DUK__EMIT_FLAG_A_IS_SOURCE,
				              reg_varbind,
				              reg_cs + 0);
			} else {
				/* XXX: expand target register or constant field to
				 * reduce shuffling.
				 */
				DUK_ASSERT(DUK__ISCONST(rc_varname));
				duk__emit_a_b(comp_ctx,
				              DUK_OP_CSVAR | DUK__EMIT_FLAG_BC_REGCONST,
				              reg_cs + 0,
				              rc_varname);
			}
		} else if (left->t == DUK_IVAL_PROP) {
			/* Call through a property lookup, E5 Section 11.2.3, step 6.a.i,
			 * E5 Section 10.4.3.  There used to be a separate CSPROP opcode
			 * but a typical call setup took 3 opcodes (e.g. LDREG, LDCONST,
			 * CSPROP) and the same can be achieved with ordinary loads.
			 */
#if defined(DUK_USE_VERBOSE_ERRORS)
			duk_regconst_t reg_key;
#endif

			DUK_DDD(DUK_DDDPRINT("function call with property base"));

			/* XXX: For Math.sin() this generates: LDCONST + LDREG +
			 * GETPROPC + call.  The LDREG is unnecessary because LDCONST
			 * could be loaded directly into reg_cs + 1.  This doesn't
			 * happen now because a variable cannot be in left->x1 of a
			 * DUK_IVAL_PROP.  We could notice that left->x1 is a temp
			 * and reuse, but it would still be in the wrong position
			 * (reg_cs + 0 rather than reg_cs + 1).
			 */
			duk__ispec_toforcedreg(comp_ctx, &left->x1, reg_cs + 1);  /* base */
#if defined(DUK_USE_VERBOSE_ERRORS)
			reg_key = duk__ispec_toregconst_raw(comp_ctx, &left->x2, -1, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_GETPROPC | DUK__EMIT_FLAG_BC_REGCONST,
			                reg_cs + 0,
			                reg_cs + 1,
			                reg_key);
#else
			duk__ivalue_toforcedreg(comp_ctx, left, reg_cs + 0);  /* base[key] */
#endif
		} else {
			DUK_DDD(DUK_DDDPRINT("function call with register base"));

			duk__ivalue_toforcedreg(comp_ctx, left, reg_cs + 0);
#if 0
			duk__emit_a_bc(comp_ctx,
			               DUK_OP_CSREG | DUK__EMIT_FLAG_A_IS_SOURCE,
			               reg_cs + 0,
			               reg_cs + 0);  /* in-place setup */
#endif
			/* Because of in-place setup, REGCS is equivalent to
			 * just this LDUNDEF.
			 */
			duk__emit_bc(comp_ctx, DUK_OP_LDUNDEF, reg_cs + 1);
		}

		DUK__SETTEMP(comp_ctx, reg_cs + 2);
		nargs = duk__parse_arguments(comp_ctx, res);  /* parse args starting from "next temp" */

		/* Tailcalls are handled by back-patching the already emitted opcode
		 * later in return statement parser.
		 */

		duk__emit_a_bc(comp_ctx,
		               call_op,
		               (duk_regconst_t) nargs /*numargs*/,
		               reg_cs /*basereg*/);
		DUK__SETTEMP(comp_ctx, reg_cs + 1);    /* result in csreg */

		duk__ivalue_regconst(res, reg_cs);
		return;
	}

	/* POSTFIX EXPRESSION */

	case DUK_TOK_INCREMENT: {
		args = (DUK_OP_POSTINCP_RR << 16) + (DUK_OP_POSTINCR << 8) + 0;
		goto postincdec;
	}
	case DUK_TOK_DECREMENT: {
		args = (DUK_OP_POSTDECP_RR << 16) + (DUK_OP_POSTDECR << 8) + 0;
		goto postincdec;
	}

	/* EXPONENTIATION EXPRESSION */

#if defined(DUK_USE_ES7_EXP_OPERATOR)
	case DUK_TOK_EXP: {
		args = (DUK_OP_EXP << 8) + DUK__BP_EXPONENTIATION - 1;  /* UnaryExpression */
		goto binary;
	}
#endif

	/* MULTIPLICATIVE EXPRESSION */

	case DUK_TOK_MUL: {
		args = (DUK_OP_MUL << 8) + DUK__BP_MULTIPLICATIVE;  /* ExponentiationExpression */
		goto binary;
	}
	case DUK_TOK_DIV: {
		args = (DUK_OP_DIV << 8) + DUK__BP_MULTIPLICATIVE;  /* ExponentiationExpression */
		goto binary;
	}
	case DUK_TOK_MOD: {
		args = (DUK_OP_MOD << 8) + DUK__BP_MULTIPLICATIVE;  /* ExponentiationExpression */
		goto binary;
	}

	/* ADDITIVE EXPRESSION */

	case DUK_TOK_ADD: {
		args = (DUK_OP_ADD << 8) + DUK__BP_ADDITIVE;  /* MultiplicativeExpression */
		goto binary;
	}
	case DUK_TOK_SUB: {
		args = (DUK_OP_SUB << 8) + DUK__BP_ADDITIVE;  /* MultiplicativeExpression */
		goto binary;
	}

	/* SHIFT EXPRESSION */

	case DUK_TOK_ALSHIFT: {
		/* << */
		args = (DUK_OP_BASL << 8) + DUK__BP_SHIFT;
		goto binary;
	}
	case DUK_TOK_ARSHIFT: {
		/* >> */
		args = (DUK_OP_BASR << 8) + DUK__BP_SHIFT;
		goto binary;
	}
	case DUK_TOK_RSHIFT: {
		/* >>> */
		args = (DUK_OP_BLSR << 8) + DUK__BP_SHIFT;
		goto binary;
	}

	/* RELATIONAL EXPRESSION */

	case DUK_TOK_LT: {
		/* < */
		args = (DUK_OP_LT << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}
	case DUK_TOK_GT: {
		args = (DUK_OP_GT << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}
	case DUK_TOK_LE: {
		args = (DUK_OP_LE << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}
	case DUK_TOK_GE: {
		args = (DUK_OP_GE << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}
	case DUK_TOK_INSTANCEOF: {
		args = (DUK_OP_INSTOF << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}
	case DUK_TOK_IN: {
		args = (DUK_OP_IN << 8) + DUK__BP_RELATIONAL;
		goto binary;
	}

	/* EQUALITY EXPRESSION */

	case DUK_TOK_EQ: {
		args = (DUK_OP_EQ << 8) + DUK__BP_EQUALITY;
		goto binary;
	}
	case DUK_TOK_NEQ: {
		args = (DUK_OP_NEQ << 8) + DUK__BP_EQUALITY;
		goto binary;
	}
	case DUK_TOK_SEQ: {
		args = (DUK_OP_SEQ << 8) + DUK__BP_EQUALITY;
		goto binary;
	}
	case DUK_TOK_SNEQ: {
		args = (DUK_OP_SNEQ << 8) + DUK__BP_EQUALITY;
		goto binary;
	}

	/* BITWISE EXPRESSIONS */

	case DUK_TOK_BAND: {
		args = (DUK_OP_BAND << 8) + DUK__BP_BAND;
		goto binary;
	}
	case DUK_TOK_BXOR: {
		args = (DUK_OP_BXOR << 8) + DUK__BP_BXOR;
		goto binary;
	}
	case DUK_TOK_BOR: {
		args = (DUK_OP_BOR << 8) + DUK__BP_BOR;
		goto binary;
	}

	/* LOGICAL EXPRESSIONS */

	case DUK_TOK_LAND: {
		/* syntactically left-associative but parsed as right-associative */
		args = (1 << 8) + DUK__BP_LAND - 1;
		goto binary_logical;
	}
	case DUK_TOK_LOR: {
		/* syntactically left-associative but parsed as right-associative */
		args = (0 << 8) + DUK__BP_LOR - 1;
		goto binary_logical;
	}

	/* CONDITIONAL EXPRESSION */

	case DUK_TOK_QUESTION: {
		/* XXX: common reg allocation need is to reuse a sub-expression's temp reg,
		 * but only if it really is a temp.  Nothing fancy here now.
		 */
		duk_regconst_t reg_temp;
		duk_int_t pc_jump1;
		duk_int_t pc_jump2;

		reg_temp = DUK__ALLOCTEMP(comp_ctx);
		duk__ivalue_toforcedreg(comp_ctx, left, reg_temp);
		duk__emit_if_true_skip(comp_ctx, reg_temp);
		pc_jump1 = duk__emit_jump_empty(comp_ctx);  /* jump to false */
		duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);  /* AssignmentExpression */
		duk__advance_expect(comp_ctx, DUK_TOK_COLON);
		pc_jump2 = duk__emit_jump_empty(comp_ctx);  /* jump to end */
		duk__patch_jump_here(comp_ctx, pc_jump1);
		duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);  /* AssignmentExpression */
		duk__patch_jump_here(comp_ctx, pc_jump2);

		DUK__SETTEMP(comp_ctx, reg_temp + 1);
		duk__ivalue_regconst(res, reg_temp);
		return;
	}

	/* ASSIGNMENT EXPRESSION */

	case DUK_TOK_EQUALSIGN: {
		/*
		 *  Assignments are right associative, allows e.g.
		 *    a = 5;
		 *    a += b = 9;   // same as a += (b = 9)
		 *  -> expression value 14, a = 14, b = 9
		 *
		 *  Right associativiness is reflected in the BP for recursion,
		 *  "-1" ensures assignment operations are allowed.
		 *
		 *  XXX: just use DUK__BP_COMMA (i.e. no need for 2-step bp levels)?
		 */
		args = (DUK_OP_NONE << 8) + DUK__BP_ASSIGNMENT - 1;   /* DUK_OP_NONE marks a 'plain' assignment */
		goto assign;
	}
	case DUK_TOK_ADD_EQ: {
		/* right associative */
		args = (DUK_OP_ADD << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_SUB_EQ: {
		/* right associative */
		args = (DUK_OP_SUB << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_MUL_EQ: {
		/* right associative */
		args = (DUK_OP_MUL << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_DIV_EQ: {
		/* right associative */
		args = (DUK_OP_DIV << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_MOD_EQ: {
		/* right associative */
		args = (DUK_OP_MOD << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
#if defined(DUK_USE_ES7_EXP_OPERATOR)
	case DUK_TOK_EXP_EQ: {
		/* right associative */
		args = (DUK_OP_EXP << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
#endif
	case DUK_TOK_ALSHIFT_EQ: {
		/* right associative */
		args = (DUK_OP_BASL << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_ARSHIFT_EQ: {
		/* right associative */
		args = (DUK_OP_BASR << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_RSHIFT_EQ: {
		/* right associative */
		args = (DUK_OP_BLSR << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_BAND_EQ: {
		/* right associative */
		args = (DUK_OP_BAND << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_BOR_EQ: {
		/* right associative */
		args = (DUK_OP_BOR << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}
	case DUK_TOK_BXOR_EQ: {
		/* right associative */
		args = (DUK_OP_BXOR << 8) + DUK__BP_ASSIGNMENT - 1;
		goto assign;
	}

	/* COMMA */

	case DUK_TOK_COMMA: {
		/* right associative */

		duk__ivalue_toplain_ignore(comp_ctx, left);  /* need side effects, not value */
		duk__expr_toplain(comp_ctx, res, DUK__BP_COMMA - 1 /*rbp_flags*/);

		/* return 'res' (of right part) as our result */
		return;
	}

	default: {
		break;
	}
	}

	DUK_D(DUK_DPRINT("parse error: unexpected token: %ld", (long) tok));
	DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
	DUK_WO_NORETURN(return;);

#if 0
	/* XXX: shared handling for 'duk__expr_lhs'? */
	if (comp_ctx->curr_func.paren_level == 0 && XXX) {
		comp_ctx->curr_func.duk__expr_lhs = 0;
	}
#endif

 binary:
	/*
	 *  Shared handling of binary operations
	 *
	 *  args = (opcode << 8) + rbp
	 */
	{
		duk__ivalue_toplain(comp_ctx, left);
		duk__expr_toplain(comp_ctx, res, args & 0xff /*rbp_flags*/);

		/* combine left->x1 and res->x1 (right->x1, really) -> (left->x1 OP res->x1) */
		DUK_ASSERT(left->t == DUK_IVAL_PLAIN);
		DUK_ASSERT(res->t == DUK_IVAL_PLAIN);

		res->t = DUK_IVAL_ARITH;
		res->op = (args >> 8) & 0xff;

		res->x2.t = res->x1.t;
		res->x2.regconst = res->x1.regconst;
		duk_copy(thr, res->x1.valstack_idx, res->x2.valstack_idx);

		res->x1.t = left->x1.t;
		res->x1.regconst = left->x1.regconst;
		duk_copy(thr, left->x1.valstack_idx, res->x1.valstack_idx);

		DUK_DDD(DUK_DDDPRINT("binary op, res: t=%ld, x1.t=%ld, x1.regconst=0x%08lx, x2.t=%ld, x2.regconst=0x%08lx",
		                     (long) res->t, (long) res->x1.t, (unsigned long) res->x1.regconst, (long) res->x2.t, (unsigned long) res->x2.regconst));
		return;
	}

 binary_logical:
	/*
	 *  Shared handling for logical AND and logical OR.
	 *
	 *  args = (truthval << 8) + rbp
	 *
	 *  Truthval determines when to skip right-hand-side.
	 *  For logical AND truthval=1, for logical OR truthval=0.
	 *
	 *  See doc/compiler.rst for discussion on compiling logical
	 *  AND and OR expressions.  The approach here is very simplistic,
	 *  generating extra jumps and multiple evaluations of truth values,
	 *  but generates code on-the-fly with only local back-patching.
	 *
	 *  Both logical AND and OR are syntactically left-associated.
	 *  However, logical ANDs are compiled as right associative
	 *  expressions, i.e. "A && B && C" as "A && (B && C)", to allow
	 *  skip jumps to skip over the entire tail.  Similarly for logical OR.
	 */

	{
		duk_regconst_t reg_temp;
		duk_int_t pc_jump;
		duk_small_uint_t args_truthval = args >> 8;
		duk_small_uint_t args_rbp = args & 0xff;

		/* XXX: unoptimal use of temps, resetting */

		reg_temp = DUK__ALLOCTEMP(comp_ctx);

		duk__ivalue_toforcedreg(comp_ctx, left, reg_temp);
		DUK_ASSERT(DUK__ISREG(reg_temp));
		duk__emit_bc(comp_ctx,
		            (args_truthval ? DUK_OP_IFTRUE_R : DUK_OP_IFFALSE_R),
		            reg_temp);  /* skip jump conditionally */
		pc_jump = duk__emit_jump_empty(comp_ctx);
		duk__expr_toforcedreg(comp_ctx, res, args_rbp /*rbp_flags*/, reg_temp /*forced_reg*/);
		duk__patch_jump_here(comp_ctx, pc_jump);

		duk__ivalue_regconst(res, reg_temp);
		return;
	}

 assign:
	/*
	 *  Shared assignment expression handling
	 *
	 *  args = (opcode << 8) + rbp
	 *
	 *  If 'opcode' is DUK_OP_NONE, plain assignment without arithmetic.
	 *  Syntactically valid left-hand-side forms which are not accepted as
	 *  left-hand-side values (e.g. as in "f() = 1") must NOT cause a
	 *  SyntaxError, but rather a run-time ReferenceError.
	 *
	 *  When evaluating X <op>= Y, the LHS (X) is conceptually evaluated
	 *  to a temporary first.  The RHS is then evaluated.  Finally, the
	 *  <op> is applied to the initial value of RHS (not the value after
	 *  RHS evaluation), and written to X.  Doing so concretely generates
	 *  inefficient code so we'd like to avoid the temporary when possible.
	 *  See: https://github.com/svaarala/duktape/pull/992.
	 *
	 *  The expression value (final LHS value, written to RHS) is
	 *  conceptually copied into a fresh temporary so that it won't
	 *  change even if the LHS/RHS values change in outer expressions.
	 *  For example, it'd be generally incorrect for the expression value
	 *  to be the RHS register binding, unless there's a guarantee that it
	 *  won't change during further expression evaluation.  Using the
	 *  temporary concretely produces inefficient bytecode, so we try to
	 *  avoid the extra temporary for some known-to-be-safe cases.
	 *  Currently the only safe case we detect is a "top level assignment",
	 *  for example "x = y + z;", where the assignment expression value is
	 *  ignored.
	 *  See: test-dev-assign-expr.js and test-bug-assign-mutate-gh381.js.
	 */

	{
		duk_small_uint_t args_op = args >> 8;
		duk_small_uint_t args_rbp = args & 0xff;
		duk_bool_t toplevel_assign;

		/* XXX: here we need to know if 'left' is left-hand-side compatible.
		 * That information is no longer available from current expr parsing
		 * state; it would need to be carried into the 'left' ivalue or by
		 * some other means.
		 */

		/* A top-level assignment is e.g. "x = y;".  For these it's safe
		 * to use the RHS as-is as the expression value, even if the RHS
		 * is a reg-bound identifier.  The RHS ('res') is right associative
		 * so it has consumed all other assignment level operations; the
		 * only relevant lower binding power construct is comma operator
		 * which will ignore the expression value provided here.  Usually
		 * the top level assignment expression value is ignored, but it
		 * is relevant for e.g. eval code.
		 */
		toplevel_assign = (comp_ctx->curr_func.nud_count == 1 && /* one token before */
		                   comp_ctx->curr_func.led_count == 1);  /* one operator (= assign) */
		DUK_DDD(DUK_DDDPRINT("assignment: nud_count=%ld, led_count=%ld, toplevel_assign=%ld",
		                     (long) comp_ctx->curr_func.nud_count,
		                     (long) comp_ctx->curr_func.led_count,
		                     (long) toplevel_assign));

		if (left->t == DUK_IVAL_VAR) {
			duk_hstring *h_varname;
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;

			DUK_ASSERT(left->x1.t == DUK_ISPEC_VALUE);  /* LHS is already side effect free */

			h_varname = duk_known_hstring(thr, left->x1.valstack_idx);
			if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
				/* E5 Section 11.13.1 (and others for other assignments), step 4. */
				goto syntax_error_lvalue;
			}
			duk_dup(thr, left->x1.valstack_idx);
			(void) duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname);

			if (args_op == DUK_OP_NONE) {
				duk__expr(comp_ctx, res, args_rbp /*rbp_flags*/);
				if (toplevel_assign) {
					/* Any 'res' will do. */
					DUK_DDD(DUK_DDDPRINT("plain assignment, toplevel assign, use as is"));
				} else {
					/* 'res' must be a plain ivalue, and not register-bound variable. */
					DUK_DDD(DUK_DDDPRINT("plain assignment, not toplevel assign, ensure not a reg-bound identifier"));
					if (res->t != DUK_IVAL_PLAIN || (res->x1.t == DUK_ISPEC_REGCONST &&
					                                 DUK__ISREG_NOTTEMP(comp_ctx, res->x1.regconst))) {
						duk__ivalue_totempconst(comp_ctx, res);
					}
				}
			} else {
				/* For X <op>= Y we need to evaluate the pre-op
				 * value of X before evaluating the RHS: the RHS
				 * can change X, but when we do <op> we must use
				 * the pre-op value.
				 */
				duk_regconst_t reg_temp;

				reg_temp = DUK__ALLOCTEMP(comp_ctx);

				if (reg_varbind >= 0) {
					duk_regconst_t reg_res;
					duk_regconst_t reg_src;
					duk_int_t pc_temp_load;
					duk_int_t pc_before_rhs;
					duk_int_t pc_after_rhs;

					if (toplevel_assign) {
						/* 'reg_varbind' is the operation result and can also
						 * become the expression value for top level assignments
						 * such as: "var x; x += y;".
						 */
						DUK_DD(DUK_DDPRINT("<op>= expression is top level, write directly to reg_varbind"));
						reg_res = reg_varbind;
					} else {
						/* Not safe to use 'reg_varbind' as assignment expression
						 * value, so go through a temp.
						 */
						DUK_DD(DUK_DDPRINT("<op>= expression is not top level, write to reg_temp"));
						reg_res = reg_temp;  /* reg_res should be smallest possible */
						reg_temp = DUK__ALLOCTEMP(comp_ctx);
					}

					/* Try to optimize X <op>= Y for reg-bound
					 * variables.  Detect side-effect free RHS
					 * narrowly by seeing whether it emits code.
					 * If not, rewind the code emitter and overwrite
					 * the unnecessary temp reg load.
					 */

					pc_temp_load = duk__get_current_pc(comp_ctx);
					duk__emit_a_bc(comp_ctx,
					               DUK_OP_LDREG,
					               reg_temp,
					               reg_varbind);

					pc_before_rhs = duk__get_current_pc(comp_ctx);
					duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
					DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
					pc_after_rhs = duk__get_current_pc(comp_ctx);

					DUK_DD(DUK_DDPRINT("pc_temp_load=%ld, pc_before_rhs=%ld, pc_after_rhs=%ld",
					                   (long) pc_temp_load, (long) pc_before_rhs,
					                   (long) pc_after_rhs));

					if (pc_after_rhs == pc_before_rhs) {
						/* Note: if the reg_temp load generated shuffling
						 * instructions, we may need to rewind more than
						 * one instruction, so use explicit PC computation.
						 */
						DUK_DD(DUK_DDPRINT("rhs is side effect free, rewind and avoid unnecessary temp for reg-based <op>="));
						DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, (pc_temp_load - pc_before_rhs) * (duk_int_t) sizeof(duk_compiler_instr));
						reg_src = reg_varbind;
					} else {
						DUK_DD(DUK_DDPRINT("rhs evaluation emitted code, not sure if rhs is side effect free; use temp reg for LHS"));
						reg_src = reg_temp;
					}

					duk__emit_a_b_c(comp_ctx,
					                args_op | DUK__EMIT_FLAG_BC_REGCONST,
					                reg_res,
					                reg_src,
					                res->x1.regconst);

					res->x1.regconst = reg_res;

					/* Ensure compact use of temps. */
					if (DUK__ISREG_TEMP(comp_ctx, reg_res)) {
						DUK__SETTEMP(comp_ctx, reg_res + 1);
					}
				} else {
					/* When LHS is not register bound, always go through a
					 * temporary.  No optimization for top level assignment.
					 */

					duk__emit_a_bc(comp_ctx,
					               DUK_OP_GETVAR,
					               reg_temp,
					               rc_varname);

					duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
					DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);

					duk__emit_a_b_c(comp_ctx,
					                args_op | DUK__EMIT_FLAG_BC_REGCONST,
					                reg_temp,
					                reg_temp,
					                res->x1.regconst);
					res->x1.regconst = reg_temp;
				}

				DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
			}

			/* At this point 'res' holds the potential expression value.
			 * It can be basically any ivalue here, including a reg-bound
			 * identifier (if code above deems it safe) or a unary/binary
			 * operation.  Operations must be resolved to a side effect free
			 * plain value, and the side effects must happen exactly once.
			 */

			if (reg_varbind >= 0) {
				if (res->t != DUK_IVAL_PLAIN) {
					/* Resolve 'res' directly into the LHS binding, and use
					 * that as the expression value if safe.  If not safe,
					 * resolve to a temp/const and copy to LHS.
					 */
					if (toplevel_assign) {
						duk__ivalue_toforcedreg(comp_ctx, res, (duk_int_t) reg_varbind);
					} else {
						duk__ivalue_totempconst(comp_ctx, res);
						duk__copy_ivalue(comp_ctx, res, left);  /* use 'left' as a temp */
						duk__ivalue_toforcedreg(comp_ctx, left, (duk_int_t) reg_varbind);
					}
				} else {
					/* Use 'res' as the expression value (it's side effect
					 * free and may be a plain value, a register, or a
					 * constant) and write it to the LHS binding too.
					 */
					duk__copy_ivalue(comp_ctx, res, left);  /* use 'left' as a temp */
					duk__ivalue_toforcedreg(comp_ctx, left, (duk_int_t) reg_varbind);
				}
			} else {
				/* Only a reg fits into 'A' so coerce 'res' into a register
				 * for PUTVAR.
				 *
				 * XXX: here the current A/B/C split is suboptimal: we could
				 * just use 9 bits for reg_res (and support constants) and 17
				 * instead of 18 bits for the varname const index.
				 */

				duk__ivalue_toreg(comp_ctx, res);
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
				               res->x1.regconst,
				               rc_varname);
			}

			/* 'res' contains expression value */
		} else if (left->t == DUK_IVAL_PROP) {
			/* E5 Section 11.13.1 (and others) step 4 never matches for prop writes -> no check */
			duk_regconst_t reg_obj;
			duk_regconst_t rc_key;
			duk_regconst_t rc_res;
			duk_regconst_t reg_temp;

			/* Property access expressions ('a[b]') are critical to correct
			 * LHS evaluation ordering, see test-dev-assign-eval-order*.js.
			 * We must make sure that the LHS target slot (base object and
			 * key) don't change during RHS evaluation.  The only concrete
			 * problem is a register reference to a variable-bound register
			 * (i.e., non-temp).  Require temp regs for both key and base.
			 *
			 * Don't allow a constant for the object (even for a number
			 * etc), as it goes into the 'A' field of the opcode.
			 */

			reg_obj = duk__ispec_toregconst_raw(comp_ctx,
			                                    &left->x1,
			                                    -1 /*forced_reg*/,
			                                    DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);

			rc_key = duk__ispec_toregconst_raw(comp_ctx,
			                                   &left->x2,
			                                   -1 /*forced_reg*/,
			                                   DUK__IVAL_FLAG_REQUIRE_TEMP | DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);

			/* Evaluate RHS only when LHS is safe. */

			if (args_op == DUK_OP_NONE) {
				duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
				DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
				rc_res = res->x1.regconst;
			} else {
				reg_temp = DUK__ALLOCTEMP(comp_ctx);
				duk__emit_a_b_c(comp_ctx,
				                DUK_OP_GETPROP | DUK__EMIT_FLAG_BC_REGCONST,
				                reg_temp,
				                reg_obj,
				                rc_key);

				duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
				DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);

				duk__emit_a_b_c(comp_ctx,
				                args_op | DUK__EMIT_FLAG_BC_REGCONST,
				                reg_temp,
				                reg_temp,
				                res->x1.regconst);
				rc_res = reg_temp;
			}

			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_PUTPROP | DUK__EMIT_FLAG_A_IS_SOURCE | DUK__EMIT_FLAG_BC_REGCONST,
			                reg_obj,
			                rc_key,
			                rc_res);

			duk__ivalue_regconst(res, rc_res);
		} else {
			/* No support for lvalues returned from new or function call expressions.
			 * However, these must NOT cause compile-time SyntaxErrors, but run-time
			 * ReferenceErrors.  Both left and right sides of the assignment must be
			 * evaluated before throwing a ReferenceError.  For instance:
			 *
			 *     f() = g();
			 *
			 * must result in f() being evaluated, then g() being evaluated, and
			 * finally, a ReferenceError being thrown.  See E5 Section 11.13.1.
			 */

			duk_regconst_t rc_res;

			/* First evaluate LHS fully to ensure all side effects are out. */
			duk__ivalue_toplain_ignore(comp_ctx, left);

			/* Then evaluate RHS fully (its value becomes the expression value too).
			 * Technically we'd need the side effect safety check here too, but because
			 * we always throw using INVLHS the result doesn't matter.
			 */
			rc_res = duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);

			duk__emit_op_only(comp_ctx, DUK_OP_INVLHS);

			duk__ivalue_regconst(res, rc_res);
		}

		return;
	}

 postincdec:
	{
		/*
		 *  Post-increment/decrement will return the original value as its
		 *  result value.  However, even that value will be coerced using
		 *  ToNumber() which is quite awkward.  Specific bytecode opcodes
		 *  are used to handle these semantics.
		 *
		 *  Note that post increment/decrement has a "no LineTerminator here"
		 *  restriction.  This is handled by duk__expr_lbp(), which forcibly terminates
		 *  the previous expression if a LineTerminator occurs before '++'/'--'.
		 */

		duk_regconst_t reg_res;
		duk_small_uint_t args_op1 = (args >> 8) & 0xff;  /* DUK_OP_POSTINCR/DUK_OP_POSTDECR */
		duk_small_uint_t args_op2 = args >> 16;          /* DUK_OP_POSTINCP_RR/DUK_OP_POSTDECP_RR */

		/* Specific assumptions for opcode numbering. */
		DUK_ASSERT(DUK_OP_POSTINCR + 4 == DUK_OP_POSTINCV);
		DUK_ASSERT(DUK_OP_POSTDECR + 4 == DUK_OP_POSTDECV);

		reg_res = DUK__ALLOCTEMP(comp_ctx);

		if (left->t == DUK_IVAL_VAR) {
			duk_hstring *h_varname;
			duk_regconst_t reg_varbind;
			duk_regconst_t rc_varname;

			h_varname = duk_known_hstring(thr, left->x1.valstack_idx);

			if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
				goto syntax_error;
			}

			duk_dup(thr, left->x1.valstack_idx);
			if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
				duk__emit_a_bc(comp_ctx,
				               args_op1,  /* e.g. DUK_OP_POSTINCR */
				               reg_res,
				               reg_varbind);
			} else {
				duk__emit_a_bc(comp_ctx,
				               args_op1 + 4,  /* e.g. DUK_OP_POSTINCV */
				               reg_res,
				               rc_varname);
			}

			DUK_DDD(DUK_DDDPRINT("postincdec to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
			                     (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));
		} else if (left->t == DUK_IVAL_PROP) {
			duk_regconst_t reg_obj;  /* allocate to reg only (not const) */
			duk_regconst_t rc_key;

			reg_obj = duk__ispec_toregconst_raw(comp_ctx, &left->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
			rc_key = duk__ispec_toregconst_raw(comp_ctx, &left->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
			duk__emit_a_b_c(comp_ctx,
			                args_op2 | DUK__EMIT_FLAG_BC_REGCONST,  /* e.g. DUK_OP_POSTINCP */
			                reg_res,
			                reg_obj,
			                rc_key);
		} else {
			/* Technically return value is not needed because INVLHS will
			 * unconditially throw a ReferenceError.  Coercion is necessary
			 * for proper semantics (consider ToNumber() called for an object).
			 * Use DUK_OP_UNP with a dummy register to get ToNumber().
			 */
			duk__ivalue_toforcedreg(comp_ctx, left, reg_res);
			duk__emit_bc(comp_ctx,
			             DUK_OP_UNP,
			             reg_res);  /* for side effects, result ignored */
			duk__emit_op_only(comp_ctx,
			                  DUK_OP_INVLHS);
		}

		DUK__SETTEMP(comp_ctx, reg_res + 1);
		duk__ivalue_regconst(res, reg_res);
		return;
	}

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_EXPRESSION);
	DUK_WO_NORETURN(return;);

 syntax_error_lvalue:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LVALUE);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL duk_small_uint_t duk__expr_lbp(duk_compiler_ctx *comp_ctx) {
	duk_small_uint_t tok = comp_ctx->curr_token.t;

	DUK_ASSERT_DISABLE(tok >= DUK_TOK_MINVAL);  /* unsigned */
	DUK_ASSERT(tok <= DUK_TOK_MAXVAL);
	DUK_ASSERT(sizeof(duk__token_lbp) == DUK_TOK_MAXVAL + 1);

	/* XXX: integrate support for this into led() instead?
	 * Similar issue as post-increment/post-decrement.
	 */

	/* prevent duk__expr_led() by using a binding power less than anything valid */
	if (tok == DUK_TOK_IN && !comp_ctx->curr_func.allow_in) {
		return 0;
	}

	if ((tok == DUK_TOK_DECREMENT || tok == DUK_TOK_INCREMENT) &&
	    (comp_ctx->curr_token.lineterm)) {
		/* '++' or '--' in a post-increment/decrement position,
		 * and a LineTerminator occurs between the operator and
		 * the preceding expression.  Force the previous expr
		 * to terminate, in effect treating e.g. "a,b\n++" as
		 * "a,b;++" (= SyntaxError).
		 */
		return 0;
	}

	return DUK__TOKEN_LBP_GET_BP(duk__token_lbp[tok]);  /* format is bit packed */
}

/*
 *  Expression parsing.
 *
 *  Upon entry to 'expr' and its variants, 'curr_tok' is assumed to be the
 *  first token of the expression.  Upon exit, 'curr_tok' will be the first
 *  token not part of the expression (e.g. semicolon terminating an expression
 *  statement).
 */

#define DUK__EXPR_RBP_MASK           0xff
#define DUK__EXPR_FLAG_REJECT_IN     (1 << 8)   /* reject 'in' token (used for for-in) */
#define DUK__EXPR_FLAG_ALLOW_EMPTY   (1 << 9)   /* allow empty expression */
#define DUK__EXPR_FLAG_REQUIRE_INIT  (1 << 10)  /* require initializer for var/const */

/* main expression parser function */
DUK_LOCAL void duk__expr(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk_hthread *thr = comp_ctx->thr;
	duk_ivalue tmp_alloc;   /* 'res' is used for "left", and 'tmp' for "right" */
	duk_ivalue *tmp = &tmp_alloc;
	duk_small_uint_t rbp;

	DUK__RECURSION_INCREASE(comp_ctx, thr);

	duk_require_stack(thr, DUK__PARSE_EXPR_SLOTS);

	/* filter out flags from exprtop rbp_flags here to save space */
	rbp = rbp_flags & DUK__EXPR_RBP_MASK;

	DUK_DDD(DUK_DDDPRINT("duk__expr(), rbp_flags=%ld, rbp=%ld, allow_in=%ld, paren_level=%ld",
	                     (long) rbp_flags, (long) rbp, (long) comp_ctx->curr_func.allow_in,
	                     (long) comp_ctx->curr_func.paren_level));

	duk_memzero(&tmp_alloc, sizeof(tmp_alloc));
	tmp->x1.valstack_idx = duk_get_top(thr);
	tmp->x2.valstack_idx = tmp->x1.valstack_idx + 1;
	duk_push_undefined(thr);
	duk_push_undefined(thr);

	/* XXX: where to release temp regs in intermediate expressions?
	 * e.g. 1+2+3 -> don't inflate temp register count when parsing this.
	 * that particular expression temp regs can be forced here.
	 */

	/* XXX: increase ctx->expr_tokens here for every consumed token
	 * (this would be a nice statistic)?
	 */

	if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON || comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
		/* XXX: possibly incorrect handling of empty expression */
		DUK_DDD(DUK_DDDPRINT("empty expression"));
		if (!(rbp_flags & DUK__EXPR_FLAG_ALLOW_EMPTY)) {
			DUK_ERROR_SYNTAX(thr, DUK_STR_EMPTY_EXPR_NOT_ALLOWED);
			DUK_WO_NORETURN(return;);
		}
		duk_push_undefined(thr);
		duk__ivalue_plain_fromstack(comp_ctx, res);
		goto cleanup;
	}

	duk__advance(comp_ctx);
	duk__expr_nud(comp_ctx, res);  /* reuse 'res' as 'left' */
	while (rbp < duk__expr_lbp(comp_ctx)) {
		duk__advance(comp_ctx);
		duk__expr_led(comp_ctx, res, tmp);
		duk__copy_ivalue(comp_ctx, tmp, res);  /* tmp -> res */
	}

 cleanup:
	/* final result is already in 'res' */

	duk_pop_2(thr);

	DUK__RECURSION_DECREASE(comp_ctx, thr);
}

DUK_LOCAL void duk__exprtop(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk_hthread *thr = comp_ctx->thr;

	/* Note: these variables must reside in 'curr_func' instead of the global
	 * context: when parsing function expressions, expression parsing is nested.
	 */
	comp_ctx->curr_func.nud_count = 0;
	comp_ctx->curr_func.led_count = 0;
	comp_ctx->curr_func.paren_level = 0;
	comp_ctx->curr_func.expr_lhs = 1;
	comp_ctx->curr_func.allow_in = (rbp_flags & DUK__EXPR_FLAG_REJECT_IN ? 0 : 1);

	duk__expr(comp_ctx, res, rbp_flags);

	if (!(rbp_flags & DUK__EXPR_FLAG_ALLOW_EMPTY) && duk__expr_is_empty(comp_ctx)) {
		DUK_ERROR_SYNTAX(thr, DUK_STR_EMPTY_EXPR_NOT_ALLOWED);
		DUK_WO_NORETURN(return;);
	}
}

/* A bunch of helpers (for size optimization) that combine duk__expr()/duk__exprtop()
 * and result conversions.
 *
 * Each helper needs at least 2-3 calls to make it worth while to wrap.
 */

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__expr_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	return duk__ivalue_toreg(comp_ctx, res);
}
#endif

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__expr_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	return duk__ivalue_totemp(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__expr_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_regconst_t forced_reg) {
	DUK_ASSERT(forced_reg >= 0);
	duk__expr(comp_ctx, res, rbp_flags);
	duk__ivalue_toforcedreg(comp_ctx, res, forced_reg);
}

DUK_LOCAL duk_regconst_t duk__expr_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	return duk__ivalue_toregconst(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__expr_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	return duk__ivalue_totempconst(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__expr_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	duk__ivalue_toplain(comp_ctx, res);
}

DUK_LOCAL void duk__expr_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__expr(comp_ctx, res, rbp_flags);
	duk__ivalue_toplain_ignore(comp_ctx, res);
}

DUK_LOCAL duk_regconst_t duk__exprtop_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__exprtop(comp_ctx, res, rbp_flags);
	return duk__ivalue_toreg(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__exprtop_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__exprtop(comp_ctx, res, rbp_flags);
	return duk__ivalue_totemp(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__exprtop_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_regconst_t forced_reg) {
	DUK_ASSERT(forced_reg >= 0);
	duk__exprtop(comp_ctx, res, rbp_flags);
	duk__ivalue_toforcedreg(comp_ctx, res, forced_reg);
}

DUK_LOCAL duk_regconst_t duk__exprtop_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
	duk__exprtop(comp_ctx, res, rbp_flags);
	return duk__ivalue_toregconst(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL void duk__exprtop_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, int rbp_flags) {
	duk__exprtop(comp_ctx, res, rbp_flags);
	duk__ivalue_toplain_ignore(comp_ctx, res);
}
#endif

/*
 *  Parse an individual source element (top level statement) or a statement.
 *
 *  Handles labeled statements automatically (peeling away labels before
 *  parsing an expression that follows the label(s)).
 *
 *  Upon entry, 'curr_tok' contains the first token of the statement (parsed
 *  in "allow regexp literal" mode).  Upon exit, 'curr_tok' contains the first
 *  token following the statement (if the statement has a terminator, this is
 *  the token after the terminator).
 */

#define DUK__HAS_VAL                  (1 << 0)  /* stmt has non-empty value */
#define DUK__HAS_TERM                 (1 << 1)  /* stmt has explicit/implicit semicolon terminator */
#define DUK__ALLOW_AUTO_SEMI_ALWAYS   (1 << 2)  /* allow automatic semicolon even without lineterm (compatibility) */
#define DUK__STILL_PROLOGUE           (1 << 3)  /* statement does not terminate directive prologue */
#define DUK__IS_TERMINAL              (1 << 4)  /* statement is guaranteed to be terminal (control doesn't flow to next statement) */

/* Parse a single variable declaration (e.g. "i" or "i=10").  A leading 'var'
 * has already been eaten.  These is no return value in 'res', it is used only
 * as a temporary.
 *
 * When called from 'for-in' statement parser, the initializer expression must
 * not allow the 'in' token.  The caller supply additional expression parsing
 * flags (like DUK__EXPR_FLAG_REJECT_IN) in 'expr_flags'.
 *
 * Finally, out_rc_varname and out_reg_varbind are updated to reflect where
 * the identifier is bound:
 *
 *    If register bound:      out_reg_varbind >= 0, out_rc_varname == 0 (ignore)
 *    If not register bound:  out_reg_varbind < 0, out_rc_varname >= 0
 *
 * These allow the caller to use the variable for further assignment, e.g.
 * as is done in 'for-in' parsing.
 */

DUK_LOCAL void duk__parse_var_decl(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags, duk_regconst_t *out_reg_varbind, duk_regconst_t *out_rc_varname) {
	duk_hthread *thr = comp_ctx->thr;
	duk_hstring *h_varname;
	duk_regconst_t reg_varbind;
	duk_regconst_t rc_varname;

	/* assume 'var' has been eaten */

	/* Note: Identifier rejects reserved words */
	if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
		goto syntax_error;
	}
	h_varname = comp_ctx->curr_token.str1;

	DUK_ASSERT(h_varname != NULL);

	/* strict mode restrictions (E5 Section 12.2.1) */
	if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
		goto syntax_error;
	}

	/* register declarations in first pass */
	if (comp_ctx->curr_func.in_scanning) {
		duk_uarridx_t n;
		DUK_DDD(DUK_DDDPRINT("register variable declaration %!O in pass 1",
		                     (duk_heaphdr *) h_varname));
		n = (duk_uarridx_t) duk_get_length(thr, comp_ctx->curr_func.decls_idx);
		duk_push_hstring(thr, h_varname);
		duk_put_prop_index(thr, comp_ctx->curr_func.decls_idx, n);
		duk_push_int(thr, DUK_DECL_TYPE_VAR + (0 << 8));
		duk_put_prop_index(thr, comp_ctx->curr_func.decls_idx, n + 1);
	}

	duk_push_hstring(thr, h_varname);  /* push before advancing to keep reachable */

	/* register binding lookup is based on varmap (even in first pass) */
	duk_dup_top(thr);
	(void) duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname);

	duk__advance(comp_ctx);  /* eat identifier */

	if (comp_ctx->curr_token.t == DUK_TOK_EQUALSIGN) {
		duk__advance(comp_ctx);

		DUK_DDD(DUK_DDDPRINT("vardecl, assign to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
		                     (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));

		duk__exprtop(comp_ctx, res, DUK__BP_COMMA | expr_flags /*rbp_flags*/);  /* AssignmentExpression */

		if (reg_varbind >= 0) {
			duk__ivalue_toforcedreg(comp_ctx, res, reg_varbind);
		} else {
			duk_regconst_t reg_val;
			reg_val = duk__ivalue_toreg(comp_ctx, res);
			duk__emit_a_bc(comp_ctx,
			               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
			               reg_val,
			               rc_varname);
		}
	} else {
		if (expr_flags & DUK__EXPR_FLAG_REQUIRE_INIT) {
			/* Used for minimal 'const': initializer required. */
			goto syntax_error;
		}
	}

	duk_pop(thr);  /* pop varname */

	*out_rc_varname = rc_varname;
	*out_reg_varbind = reg_varbind;

	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_VAR_DECLARATION);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__parse_var_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags) {
	duk_regconst_t reg_varbind;
	duk_regconst_t rc_varname;

	duk__advance(comp_ctx);  /* eat 'var' */

	for (;;) {
		/* rc_varname and reg_varbind are ignored here */
		duk__parse_var_decl(comp_ctx, res, 0 | expr_flags, &reg_varbind, &rc_varname);

		if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
			break;
		}
		duk__advance(comp_ctx);
	}
}

DUK_LOCAL void duk__parse_for_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
	duk_hthread *thr = comp_ctx->thr;
	duk_int_t pc_v34_lhs;         /* start variant 3/4 left-hand-side code (L1 in doc/compiler.rst example) */
	duk_regconst_t temp_reset;    /* knock back "next temp" to this whenever possible */
	duk_regconst_t reg_temps;     /* preallocated temporaries (2) for variants 3 and 4 */

	DUK_DDD(DUK_DDDPRINT("start parsing a for/for-in statement"));

	/* Two temporaries are preallocated here for variants 3 and 4 which need
	 * registers which are never clobbered by expressions in the loop
	 * (concretely: for the enumerator object and the next enumerated value).
	 * Variants 1 and 2 "release" these temps.
	 */

	reg_temps = DUK__ALLOCTEMPS(comp_ctx, 2);

	temp_reset = DUK__GETTEMP(comp_ctx);

	/*
	 *  For/for-in main variants are:
	 *
	 *    1. for (ExpressionNoIn_opt; Expression_opt; Expression_opt) Statement
	 *    2. for (var VariableDeclarationNoIn; Expression_opt; Expression_opt) Statement
	 *    3. for (LeftHandSideExpression in Expression) Statement
	 *    4. for (var VariableDeclarationNoIn in Expression) Statement
	 *
	 *  Parsing these without arbitrary lookahead or backtracking is relatively
	 *  tricky but we manage to do so for now.
	 *
	 *  See doc/compiler.rst for a detailed discussion of control flow
	 *  issues, evaluation order issues, etc.
	 */

	duk__advance(comp_ctx);  /* eat 'for' */
	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

	DUK_DDD(DUK_DDDPRINT("detecting for/for-in loop variant, pc=%ld", (long) duk__get_current_pc(comp_ctx)));

	/* a label site has been emitted by duk__parse_stmt() automatically
	 * (it will also emit the ENDLABEL).
	 */

	if (comp_ctx->curr_token.t == DUK_TOK_VAR) {
		/*
		 *  Variant 2 or 4
		 */

		duk_regconst_t reg_varbind;  /* variable binding register if register-bound (otherwise < 0) */
		duk_regconst_t rc_varname;   /* variable name reg/const, if variable not register-bound */

		duk__advance(comp_ctx);  /* eat 'var' */
		duk__parse_var_decl(comp_ctx, res, DUK__EXPR_FLAG_REJECT_IN, &reg_varbind, &rc_varname);
		DUK__SETTEMP(comp_ctx, temp_reset);

		if (comp_ctx->curr_token.t == DUK_TOK_IN) {
			/*
			 *  Variant 4
			 */

			DUK_DDD(DUK_DDDPRINT("detected for variant 4: for (var VariableDeclarationNoIn in Expression) Statement"));
			pc_v34_lhs = duk__get_current_pc(comp_ctx);  /* jump is inserted here */
			if (reg_varbind >= 0) {
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_LDREG,
				               reg_varbind,
				               reg_temps + 0);
			} else {
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
				               reg_temps + 0,
				               rc_varname);
			}
			goto parse_3_or_4;
		} else {
			/*
			 *  Variant 2
			 */

			DUK_DDD(DUK_DDDPRINT("detected for variant 2: for (var VariableDeclarationNoIn; Expression_opt; Expression_opt) Statement"));
			for (;;) {
				/* more initializers */
				if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
					break;
				}
				DUK_DDD(DUK_DDDPRINT("variant 2 has another variable initializer"));

				duk__advance(comp_ctx);  /* eat comma */
				duk__parse_var_decl(comp_ctx, res, DUK__EXPR_FLAG_REJECT_IN, &reg_varbind, &rc_varname);
			}
			goto parse_1_or_2;
		}
	} else {
		/*
		 *  Variant 1 or 3
		 */

		pc_v34_lhs = duk__get_current_pc(comp_ctx);  /* jump is inserted here (variant 3) */

		/* Note that duk__exprtop() here can clobber any reg above current temp_next,
		 * so any loop variables (e.g. enumerator) must be "preallocated".
		 */

		/* don't coerce yet to a plain value (variant 3 needs special handling) */
		duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_REJECT_IN | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression */
		if (comp_ctx->curr_token.t == DUK_TOK_IN) {
			/*
			 *  Variant 3
			 */

			/* XXX: need to determine LHS type, and check that it is LHS compatible */
			DUK_DDD(DUK_DDDPRINT("detected for variant 3: for (LeftHandSideExpression in Expression) Statement"));
			if (duk__expr_is_empty(comp_ctx)) {
				goto syntax_error;  /* LeftHandSideExpression does not allow empty expression */
			}

			if (res->t == DUK_IVAL_VAR) {
				duk_regconst_t reg_varbind;
				duk_regconst_t rc_varname;

				duk_dup(thr, res->x1.valstack_idx);
				if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
					duk__emit_a_bc(comp_ctx,
					               DUK_OP_LDREG,
					               reg_varbind,
					               reg_temps + 0);
				} else {
					duk__emit_a_bc(comp_ctx,
					               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
					               reg_temps + 0,
					               rc_varname);
				}
			} else if (res->t == DUK_IVAL_PROP) {
				/* Don't allow a constant for the object (even for a number etc), as
				 * it goes into the 'A' field of the opcode.
				 */
				duk_regconst_t reg_obj;
				duk_regconst_t rc_key;
				reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
				rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
				duk__emit_a_b_c(comp_ctx,
				                DUK_OP_PUTPROP | DUK__EMIT_FLAG_A_IS_SOURCE | DUK__EMIT_FLAG_BC_REGCONST,
				                reg_obj,
				                rc_key,
				                reg_temps + 0);
			} else {
				duk__ivalue_toplain_ignore(comp_ctx, res);  /* just in case */
				duk__emit_op_only(comp_ctx,
				                  DUK_OP_INVLHS);
			}
			goto parse_3_or_4;
		} else {
			/*
			 *  Variant 1
			 */

			DUK_DDD(DUK_DDDPRINT("detected for variant 1: for (ExpressionNoIn_opt; Expression_opt; Expression_opt) Statement"));
			duk__ivalue_toplain_ignore(comp_ctx, res);
			goto parse_1_or_2;
		}
	}

 parse_1_or_2:
	/*
	 *  Parse variant 1 or 2.  The first part expression (which differs
	 *  in the variants) has already been parsed and its code emitted.
	 *
	 *  reg_temps + 0: unused
	 *  reg_temps + 1: unused
	 */
	{
		duk_regconst_t rc_cond;
		duk_int_t pc_l1, pc_l2, pc_l3, pc_l4;
		duk_int_t pc_jumpto_l3, pc_jumpto_l4;
		duk_bool_t expr_c_empty;

		DUK_DDD(DUK_DDDPRINT("shared code for parsing variants 1 and 2"));

		/* "release" preallocated temps since we won't need them */
		temp_reset = reg_temps + 0;
		DUK__SETTEMP(comp_ctx, temp_reset);

		duk__advance_expect(comp_ctx, DUK_TOK_SEMICOLON);

		pc_l1 = duk__get_current_pc(comp_ctx);
		duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression_opt */
		if (duk__expr_is_empty(comp_ctx)) {
			/* no need to coerce */
			pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* to body */
			pc_jumpto_l4 = -1;  /* omitted */
		} else {
			rc_cond = duk__ivalue_toregconst(comp_ctx, res);
			duk__emit_if_false_skip(comp_ctx, rc_cond);
			pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* to body */
			pc_jumpto_l4 = duk__emit_jump_empty(comp_ctx);  /* to exit */
		}
		DUK__SETTEMP(comp_ctx, temp_reset);

		duk__advance_expect(comp_ctx, DUK_TOK_SEMICOLON);

		pc_l2 = duk__get_current_pc(comp_ctx);
		duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression_opt */
		if (duk__expr_is_empty(comp_ctx)) {
			/* no need to coerce */
			expr_c_empty = 1;
			/* JUMP L1 omitted */
		} else {
			duk__ivalue_toplain_ignore(comp_ctx, res);
			expr_c_empty = 0;
			duk__emit_jump(comp_ctx, pc_l1);
		}
		DUK__SETTEMP(comp_ctx, temp_reset);

		comp_ctx->curr_func.allow_regexp_in_adv = 1;
		duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* Allow RegExp as part of next stmt. */

		pc_l3 = duk__get_current_pc(comp_ctx);
		duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
		if (expr_c_empty) {
			duk__emit_jump(comp_ctx, pc_l1);
		} else {
			duk__emit_jump(comp_ctx, pc_l2);
		}
		/* temp reset is not necessary after duk__parse_stmt(), which already does it */

		pc_l4 = duk__get_current_pc(comp_ctx);

		DUK_DDD(DUK_DDDPRINT("patching jumps: jumpto_l3: %ld->%ld, jumpto_l4: %ld->%ld, "
		                     "break: %ld->%ld, continue: %ld->%ld",
			             (long) pc_jumpto_l3, (long) pc_l3, (long) pc_jumpto_l4, (long) pc_l4,
		                     (long) (pc_label_site + 1), (long) pc_l4, (long) (pc_label_site + 2), (long) pc_l2));

		duk__patch_jump(comp_ctx, pc_jumpto_l3, pc_l3);
		duk__patch_jump(comp_ctx, pc_jumpto_l4, pc_l4);
		duk__patch_jump(comp_ctx,
		                pc_label_site + 1,
		                pc_l4);                         /* break jump */
		duk__patch_jump(comp_ctx,
		                pc_label_site + 2,
		                expr_c_empty ? pc_l1 : pc_l2);  /* continue jump */
	}
	goto finished;

 parse_3_or_4:
	/*
	 *  Parse variant 3 or 4.
	 *
	 *  For variant 3 (e.g. "for (A in C) D;") the code for A (except the
	 *  final property/variable write) has already been emitted.  The first
	 *  instruction of that code is at pc_v34_lhs; a JUMP needs to be inserted
	 *  there to satisfy control flow needs.
	 *
	 *  For variant 4, if the variable declaration had an initializer
	 *  (e.g. "for (var A = B in C) D;") the code for the assignment
	 *  (B) has already been emitted.
	 *
	 *  Variables set before entering here:
	 *
	 *    pc_v34_lhs:    insert a "JUMP L2" here (see doc/compiler.rst example).
	 *    reg_temps + 0: iteration target value (written to LHS)
	 *    reg_temps + 1: enumerator object
	 */
	{
		duk_int_t pc_l1, pc_l2, pc_l3, pc_l4, pc_l5;
		duk_int_t pc_jumpto_l2, pc_jumpto_l3, pc_jumpto_l4, pc_jumpto_l5;
		duk_regconst_t reg_target;

		DUK_DDD(DUK_DDDPRINT("shared code for parsing variants 3 and 4, pc_v34_lhs=%ld", (long) pc_v34_lhs));

		DUK__SETTEMP(comp_ctx, temp_reset);

		/* First we need to insert a jump in the middle of previously
		 * emitted code to get the control flow right.  No jumps can
		 * cross the position where the jump is inserted.  See doc/compiler.rst
		 * for discussion on the intricacies of control flow and side effects
		 * for variants 3 and 4.
		 */

		duk__insert_jump_entry(comp_ctx, pc_v34_lhs);
		pc_jumpto_l2 = pc_v34_lhs;  /* inserted jump */
		pc_l1 = pc_v34_lhs + 1;     /* +1, right after inserted jump */

		/* The code for writing reg_temps + 0 to the left hand side has already
		 * been emitted.
		 */

		pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* -> loop body */

		duk__advance(comp_ctx);  /* eat 'in' */

		/* Parse enumeration target and initialize enumerator.  For 'null' and 'undefined',
		 * INITENUM will creates a 'null' enumerator which works like an empty enumerator
		 * (E5 Section 12.6.4, step 3).  Note that INITENUM requires the value to be in a
		 * register (constant not allowed).
		 */

		pc_l2 = duk__get_current_pc(comp_ctx);
		reg_target = duk__exprtop_toreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression */
		duk__emit_b_c(comp_ctx,
		              DUK_OP_INITENUM | DUK__EMIT_FLAG_B_IS_TARGET,
		              reg_temps + 1,
		              reg_target);
		pc_jumpto_l4 = duk__emit_jump_empty(comp_ctx);
		DUK__SETTEMP(comp_ctx, temp_reset);

		comp_ctx->curr_func.allow_regexp_in_adv = 1;
		duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* Allow RegExp as part of next stmt. */

		pc_l3 = duk__get_current_pc(comp_ctx);
		duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
		/* temp reset is not necessary after duk__parse_stmt(), which already does it */

		/* NEXTENUM needs a jump slot right after the main opcode.
		 * We need the code emitter to reserve the slot: if there's
		 * target shuffling, the target shuffle opcodes must happen
		 * after the jump slot (for NEXTENUM the shuffle opcodes are
		 * not needed if the enum is finished).
		 */
		pc_l4 = duk__get_current_pc(comp_ctx);
		duk__emit_b_c(comp_ctx,
		              DUK_OP_NEXTENUM | DUK__EMIT_FLAG_B_IS_TARGET | DUK__EMIT_FLAG_RESERVE_JUMPSLOT,
		              reg_temps + 0,
		              reg_temps + 1);
		pc_jumpto_l5 = comp_ctx->emit_jumpslot_pc;  /* NEXTENUM jump slot: executed when enum finished */
		duk__emit_jump(comp_ctx, pc_l1);  /* jump to next loop, using reg_v34_iter as iterated value */

		pc_l5 = duk__get_current_pc(comp_ctx);

		/* XXX: since the enumerator may be a memory expensive object,
		 * perhaps clear it explicitly here?  If so, break jump must
		 * go through this clearing operation.
		 */

		DUK_DDD(DUK_DDDPRINT("patching jumps: jumpto_l2: %ld->%ld, jumpto_l3: %ld->%ld, "
		                     "jumpto_l4: %ld->%ld, jumpto_l5: %ld->%ld, "
		                     "break: %ld->%ld, continue: %ld->%ld",
			             (long) pc_jumpto_l2, (long) pc_l2, (long) pc_jumpto_l3, (long) pc_l3,
			             (long) pc_jumpto_l4, (long) pc_l4, (long) pc_jumpto_l5, (long) pc_l5,
		                     (long) (pc_label_site + 1), (long) pc_l5, (long) (pc_label_site + 2), (long) pc_l4));

		duk__patch_jump(comp_ctx, pc_jumpto_l2, pc_l2);
		duk__patch_jump(comp_ctx, pc_jumpto_l3, pc_l3);
		duk__patch_jump(comp_ctx, pc_jumpto_l4, pc_l4);
		duk__patch_jump(comp_ctx, pc_jumpto_l5, pc_l5);
		duk__patch_jump(comp_ctx, pc_label_site + 1, pc_l5);  /* break jump */
		duk__patch_jump(comp_ctx, pc_label_site + 2, pc_l4);  /* continue jump */
	}
	goto finished;

 finished:
	DUK_DDD(DUK_DDDPRINT("end parsing a for/for-in statement"));
	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_FOR);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__parse_switch_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t temp_at_loop;
	duk_regconst_t rc_switch;    /* reg/const for switch value */
	duk_regconst_t rc_case;      /* reg/const for case value */
	duk_regconst_t reg_temp;     /* general temp register */
	duk_int_t pc_prevcase = -1;
	duk_int_t pc_prevstmt = -1;
	duk_int_t pc_default = -1;   /* -1 == not set, -2 == pending (next statement list) */

	/* Note: negative pc values are ignored when patching jumps, so no explicit checks needed */

	/*
	 *  Switch is pretty complicated because of several conflicting concerns:
	 *
	 *    - Want to generate code without an intermediate representation,
	 *      i.e., in one go
	 *
	 *    - Case selectors are expressions, not values, and may thus e.g. throw
	 *      exceptions (which causes evaluation order concerns)
	 *
	 *    - Evaluation semantics of case selectors and default clause need to be
	 *      carefully implemented to provide correct behavior even with case value
	 *      side effects
	 *
	 *    - Fall through case and default clauses; avoiding dead JUMPs if case
	 *      ends with an unconditional jump (a break or a continue)
	 *
	 *    - The same case value may occur multiple times, but evaluation rules
	 *      only process the first match before switching to a "propagation" mode
	 *      where case values are no longer evaluated
	 *
	 *  See E5 Section 12.11.  Also see doc/compiler.rst for compilation
	 *  discussion.
	 */

	duk__advance(comp_ctx);
	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);
	rc_switch = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* RegExp mode does not matter. */
	duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);

	DUK_DDD(DUK_DDDPRINT("switch value in register %ld", (long) rc_switch));

	temp_at_loop = DUK__GETTEMP(comp_ctx);

	for (;;) {
		duk_int_t num_stmts;
		duk_small_uint_t tok;

		/* sufficient for keeping temp reg numbers in check */
		DUK__SETTEMP(comp_ctx, temp_at_loop);

		if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
			break;
		}

		/*
		 *  Parse a case or default clause.
		 */

		if (comp_ctx->curr_token.t == DUK_TOK_CASE) {
			/*
			 *  Case clause.
			 *
			 *  Note: cannot use reg_case as a temp register (for SEQ target)
			 *  because it may be a constant.
			 */

			duk__patch_jump_here(comp_ctx, pc_prevcase);  /* chain jumps for case
			                                               * evaluation and checking
			                                               */

			duk__advance(comp_ctx);
			rc_case = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
			duk__advance_expect(comp_ctx, DUK_TOK_COLON);

			reg_temp = DUK__ALLOCTEMP(comp_ctx);
			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_SEQ | DUK__EMIT_FLAG_BC_REGCONST,
			                reg_temp,
			                rc_switch,
			                rc_case);
			duk__emit_if_true_skip(comp_ctx, reg_temp);

			/* jump to next case clause */
			pc_prevcase = duk__emit_jump_empty(comp_ctx);  /* no match, next case */

			/* statements go here (if any) on next loop */
		} else if (comp_ctx->curr_token.t == DUK_TOK_DEFAULT) {
			/*
			 *  Default clause.
			 */

			if (pc_default >= 0) {
				goto syntax_error;
			}
			duk__advance(comp_ctx);
			duk__advance_expect(comp_ctx, DUK_TOK_COLON);

			/* Fix for https://github.com/svaarala/duktape/issues/155:
			 * If 'default' is first clause (detected by pc_prevcase < 0)
			 * we need to ensure we stay in the matching chain.
			 */
			if (pc_prevcase < 0) {
				DUK_DD(DUK_DDPRINT("default clause is first, emit prevcase jump"));
				pc_prevcase = duk__emit_jump_empty(comp_ctx);
			}

			/* default clause matches next statement list (if any) */
			pc_default = -2;
		} else {
			/* Code is not accepted before the first case/default clause */
			goto syntax_error;
		}

		/*
		 *  Parse code after the clause.  Possible terminators are
		 *  'case', 'default', and '}'.
		 *
		 *  Note that there may be no code at all, not even an empty statement,
		 *  between case clauses.  This must be handled just like an empty statement
		 *  (omitting seemingly pointless JUMPs), to avoid situations like
		 *  test-bug-case-fallthrough.js.
		 */

		num_stmts = 0;
		if (pc_default == -2) {
			pc_default = duk__get_current_pc(comp_ctx);
		}

		/* Note: this is correct even for default clause statements:
		 * they participate in 'fall-through' behavior even if the
		 * default clause is in the middle.
		 */
		duk__patch_jump_here(comp_ctx, pc_prevstmt);  /* chain jumps for 'fall-through'
		                                               * after a case matches.
		                                               */

		for (;;) {
			tok = comp_ctx->curr_token.t;
			if (tok == DUK_TOK_CASE || tok == DUK_TOK_DEFAULT ||
			    tok == DUK_TOK_RCURLY) {
				break;
			}
			num_stmts++;
			duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
		}

		/* fall-through jump to next code of next case (backpatched) */
		pc_prevstmt = duk__emit_jump_empty(comp_ctx);

		/* XXX: would be nice to omit this jump when the jump is not
		 * reachable, at least in the obvious cases (such as the case
		 * ending with a 'break'.
		 *
		 * Perhaps duk__parse_stmt() could provide some info on whether
		 * the statement is a "dead end"?
		 *
		 * If implemented, just set pc_prevstmt to -1 when not needed.
		 */
	}

	DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RCURLY);
	comp_ctx->curr_func.allow_regexp_in_adv = 1;
	duk__advance(comp_ctx);  /* Allow RegExp as part of next stmt. */

	/* default case control flow patchup; note that if pc_prevcase < 0
	 * (i.e. no case clauses), control enters default case automatically.
	 */
	if (pc_default >= 0) {
		/* default case exists: go there if no case matches */
		duk__patch_jump(comp_ctx, pc_prevcase, pc_default);
	} else {
		/* default case does not exist, or no statements present
		 * after default case: finish case evaluation
		 */
		duk__patch_jump_here(comp_ctx, pc_prevcase);
	}

	/* fall-through control flow patchup; note that pc_prevstmt may be
	 * < 0 (i.e. no case clauses), in which case this is a no-op.
	 */
	duk__patch_jump_here(comp_ctx, pc_prevstmt);

	/* continue jump not patched, an INVALID opcode remains there */
	duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

	/* Note: 'fast' breaks will jump to pc_label_site + 1, which will
	 * then jump here.  The double jump will be eliminated by a
	 * peephole pass, resulting in an optimal jump here.  The label
	 * site jumps will remain in bytecode and will waste code size.
	 */

	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_SWITCH);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__parse_if_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_regconst_t temp_reset;
	duk_regconst_t rc_cond;
	duk_int_t pc_jump_false;

	DUK_DDD(DUK_DDDPRINT("begin parsing if statement"));

	temp_reset = DUK__GETTEMP(comp_ctx);

	duk__advance(comp_ctx);  /* eat 'if' */
	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

	rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
	duk__emit_if_true_skip(comp_ctx, rc_cond);
	pc_jump_false = duk__emit_jump_empty(comp_ctx);  /* jump to end or else part */
	DUK__SETTEMP(comp_ctx, temp_reset);

	comp_ctx->curr_func.allow_regexp_in_adv = 1;
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* Allow RegExp as part of next stmt. */

	duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);

	/* The 'else' ambiguity is resolved by 'else' binding to the innermost
	 * construct, so greedy matching is correct here.
	 */

	if (comp_ctx->curr_token.t == DUK_TOK_ELSE) {
		duk_int_t pc_jump_end;

		DUK_DDD(DUK_DDDPRINT("if has else part"));

		duk__advance(comp_ctx);

		pc_jump_end = duk__emit_jump_empty(comp_ctx);  /* jump from true part to end */
		duk__patch_jump_here(comp_ctx, pc_jump_false);

		duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);

		duk__patch_jump_here(comp_ctx, pc_jump_end);
	} else {
		DUK_DDD(DUK_DDDPRINT("if does not have else part"));

		duk__patch_jump_here(comp_ctx, pc_jump_false);
	}

	DUK_DDD(DUK_DDDPRINT("end parsing if statement"));
}

DUK_LOCAL void duk__parse_do_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
	duk_regconst_t rc_cond;
	duk_int_t pc_start;

	DUK_DDD(DUK_DDDPRINT("begin parsing do statement"));

	duk__advance(comp_ctx);  /* Eat 'do'; allow RegExp as part of next stmt. */

	pc_start = duk__get_current_pc(comp_ctx);
	duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
	duk__patch_jump_here(comp_ctx, pc_label_site + 2);  /* continue jump */

	duk__advance_expect(comp_ctx, DUK_TOK_WHILE);
	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

	rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
	duk__emit_if_false_skip(comp_ctx, rc_cond);
	duk__emit_jump(comp_ctx, pc_start);
	/* no need to reset temps, as we're finished emitting code */

	comp_ctx->curr_func.allow_regexp_in_adv = 1;  /* Allow RegExp as part of next stmt. */
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

	duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

	DUK_DDD(DUK_DDDPRINT("end parsing do statement"));
}

DUK_LOCAL void duk__parse_while_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
	duk_regconst_t temp_reset;
	duk_regconst_t rc_cond;
	duk_int_t pc_start;
	duk_int_t pc_jump_false;

	DUK_DDD(DUK_DDDPRINT("begin parsing while statement"));

	temp_reset = DUK__GETTEMP(comp_ctx);

	duk__advance(comp_ctx);  /* eat 'while' */

	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

	pc_start = duk__get_current_pc(comp_ctx);
	duk__patch_jump_here(comp_ctx, pc_label_site + 2);  /* continue jump */

	rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
	duk__emit_if_true_skip(comp_ctx, rc_cond);
	pc_jump_false = duk__emit_jump_empty(comp_ctx);
	DUK__SETTEMP(comp_ctx, temp_reset);

	comp_ctx->curr_func.allow_regexp_in_adv = 1;
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* Allow RegExp as part of next stmt. */

	duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
	duk__emit_jump(comp_ctx, pc_start);

	duk__patch_jump_here(comp_ctx, pc_jump_false);
	duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

	DUK_DDD(DUK_DDDPRINT("end parsing while statement"));
}

DUK_LOCAL void duk__parse_break_or_continue_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_bool_t is_break = (comp_ctx->curr_token.t == DUK_TOK_BREAK);
	duk_int_t label_id;
	duk_int_t label_catch_depth;
	duk_int_t label_pc;  /* points to LABEL; pc+1 = jump site for break; pc+2 = jump site for continue */
	duk_bool_t label_is_closest;

	DUK_UNREF(res);

	duk__advance(comp_ctx);  /* eat 'break' or 'continue' */

	if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON ||  /* explicit semi follows */
	    comp_ctx->curr_token.lineterm ||                /* automatic semi will be inserted */
	    comp_ctx->curr_token.allow_auto_semi) {         /* automatic semi will be inserted */
		/* break/continue without label */

		duk__lookup_active_label(comp_ctx, DUK_HTHREAD_STRING_EMPTY_STRING(thr), is_break, &label_id, &label_catch_depth, &label_pc, &label_is_closest);
	} else if (comp_ctx->curr_token.t == DUK_TOK_IDENTIFIER) {
		/* break/continue with label (label cannot be a reserved word, production is 'Identifier' */
		DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
		duk__lookup_active_label(comp_ctx, comp_ctx->curr_token.str1, is_break, &label_id, &label_catch_depth, &label_pc, &label_is_closest);
		duk__advance(comp_ctx);
	} else {
		DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_BREAK_CONT_LABEL);
		DUK_WO_NORETURN(return;);
	}

	/* Use a fast break/continue when possible.  A fast break/continue is
	 * just a jump to the LABEL break/continue jump slot, which then jumps
	 * to an appropriate place (for break, going through ENDLABEL correctly).
	 * The peephole optimizer will optimize the jump to a direct one.
	 */

	if (label_catch_depth == comp_ctx->curr_func.catch_depth &&
	    label_is_closest) {
		DUK_DDD(DUK_DDDPRINT("break/continue: is_break=%ld, label_id=%ld, label_is_closest=%ld, "
		                     "label_catch_depth=%ld, catch_depth=%ld "
		                     "-> use fast variant (direct jump)",
		                     (long) is_break, (long) label_id, (long) label_is_closest,
		                     (long) label_catch_depth, (long) comp_ctx->curr_func.catch_depth));

		duk__emit_jump(comp_ctx, label_pc + (is_break ? 1 : 2));
	} else {
		DUK_DDD(DUK_DDDPRINT("break/continue: is_break=%ld, label_id=%ld, label_is_closest=%ld, "
		                     "label_catch_depth=%ld, catch_depth=%ld "
		                     "-> use slow variant (longjmp)",
		                     (long) is_break, (long) label_id, (long) label_is_closest,
		                     (long) label_catch_depth, (long) comp_ctx->curr_func.catch_depth));

		duk__emit_bc(comp_ctx,
		             is_break ? DUK_OP_BREAK : DUK_OP_CONTINUE,
		             (duk_regconst_t) label_id);
	}
}

DUK_LOCAL void duk__parse_return_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t rc_val;

	duk__advance(comp_ctx);  /* eat 'return' */

	/* A 'return' statement is only allowed inside an actual function body,
	 * not as part of eval or global code.
	 */
	if (!comp_ctx->curr_func.is_function) {
		DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_RETURN);
		DUK_WO_NORETURN(return;);
	}

	if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON ||  /* explicit semi follows */
	    comp_ctx->curr_token.lineterm ||                /* automatic semi will be inserted */
	    comp_ctx->curr_token.allow_auto_semi) {         /* automatic semi will be inserted */
		DUK_DDD(DUK_DDDPRINT("empty return value -> undefined"));
		duk__emit_op_only(comp_ctx, DUK_OP_RETUNDEF);
	} else {
		duk_int_t pc_before_expr;
		duk_int_t pc_after_expr;

		DUK_DDD(DUK_DDDPRINT("return with a value"));

		DUK_UNREF(pc_before_expr);
		DUK_UNREF(pc_after_expr);

		pc_before_expr = duk__get_current_pc(comp_ctx);
		rc_val = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
		pc_after_expr = duk__get_current_pc(comp_ctx);

		/* Tail call check: if last opcode emitted was CALL, and
		 * the context allows it, add a tailcall flag to the CALL.
		 * This doesn't guarantee that a tail call will be allowed at
		 * runtime, so the RETURN must still be emitted.  (Duktape
		 * 0.10.0 avoided this and simulated a RETURN if a tail call
		 * couldn't be used at runtime; but this didn't work
		 * correctly with a thread yield/resume, see
		 * test-bug-tailcall-thread-yield-resume.js for discussion.)
		 *
		 * In addition to the last opcode being CALL, we also need to
		 * be sure that 'rc_val' is the result register of the CALL.
		 * For instance, for the expression 'return 0, (function ()
		 * { return 1; }), 2' the last opcode emitted is CALL (no
		 * bytecode is emitted for '2') but 'rc_val' indicates
		 * constant '2'.  Similarly if '2' is replaced by a register
		 * bound variable, no opcodes are emitted but tail call would
		 * be incorrect.
		 *
		 * This is tricky and easy to get wrong.  It would be best to
		 * track enough expression metadata to check that 'rc_val' came
		 * from that last CALL instruction.  We don't have that metadata
		 * now, so we check that 'rc_val' is a temporary register result
		 * (not a constant or a register bound variable).  There should
		 * be no way currently for 'rc_val' to be a temporary for an
		 * expression following the CALL instruction without emitting
		 * some opcodes following the CALL.  This proxy check is used
		 * below.
		 *
		 * See: test-bug-comma-expr-gh131.js.
		 *
		 * The non-standard 'caller' property disables tail calls
		 * because they pose some special cases which haven't been
		 * fixed yet.
		 */

#if defined(DUK_USE_TAILCALL)
		if (comp_ctx->curr_func.catch_depth == 0 &&   /* no catchers */
		    pc_after_expr > pc_before_expr) {         /* at least one opcode emitted */
			duk_compiler_instr *instr;
			duk_instr_t ins;
			duk_small_uint_t op;

			instr = duk__get_instr_ptr(comp_ctx, pc_after_expr - 1);
			DUK_ASSERT(instr != NULL);

			ins = instr->ins;
			op = (duk_small_uint_t) DUK_DEC_OP(ins);
			if ((op & ~0x0fU) == DUK_OP_CALL0 &&
			    DUK__ISREG_TEMP(comp_ctx, rc_val) /* see above */) {
				DUK_DDD(DUK_DDDPRINT("return statement detected a tail call opportunity: "
				                     "catch depth is 0, duk__exprtop() emitted >= 1 instructions, "
				                     "and last instruction is a CALL "
				                     "-> change to TAILCALL"));
				ins |= DUK_ENC_OP(DUK_BC_CALL_FLAG_TAILCALL);
				instr->ins = ins;
			}
		}
#endif  /* DUK_USE_TAILCALL */

		if (DUK__ISREG(rc_val)) {
			duk__emit_bc(comp_ctx, DUK_OP_RETREG, rc_val);
		} else {
			rc_val = DUK__REMOVECONST(rc_val);
			if (duk__const_needs_refcount(comp_ctx, rc_val)) {
				duk__emit_bc(comp_ctx, DUK_OP_RETCONST, rc_val);
			} else {
				duk__emit_bc(comp_ctx, DUK_OP_RETCONSTN, rc_val);
			}
		}
	}
}

DUK_LOCAL void duk__parse_throw_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_regconst_t reg_val;

	duk__advance(comp_ctx);  /* eat 'throw' */

	/* Unlike break/continue, throw statement does not allow an empty value. */

	if (comp_ctx->curr_token.lineterm) {
		DUK_ERROR_SYNTAX(comp_ctx->thr, DUK_STR_INVALID_THROW);
		DUK_WO_NORETURN(return;);
	}

	reg_val = duk__exprtop_toreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
	duk__emit_bc(comp_ctx,
	             DUK_OP_THROW,
	             reg_val);
}

DUK_LOCAL void duk__parse_try_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_hthread *thr = comp_ctx->thr;
	duk_regconst_t reg_catch;      /* reg_catch+0 and reg_catch+1 are reserved for TRYCATCH */
	duk_regconst_t rc_varname = 0;
	duk_small_uint_t trycatch_flags = 0;
	duk_int_t pc_ldconst = -1;
	duk_int_t pc_trycatch = -1;
	duk_int_t pc_catch = -1;
	duk_int_t pc_finally = -1;

	DUK_UNREF(res);

	/*
	 *  See the following documentation for discussion:
	 *
	 *    doc/execution.rst: control flow details
	 *
	 *  Try, catch, and finally "parts" are Blocks, not Statements, so
	 *  they must always be delimited by curly braces.  This is unlike e.g.
	 *  the if statement, which accepts any Statement.  This eliminates any
	 *  questions of matching parts of nested try statements.  The Block
	 *  parsing is implemented inline here (instead of calling out).
	 *
	 *  Finally part has a 'let scoped' variable, which requires a few kinks
	 *  here.
	 */

	comp_ctx->curr_func.catch_depth++;

	duk__advance(comp_ctx);  /* eat 'try' */

	reg_catch = DUK__ALLOCTEMPS(comp_ctx, 2);

	/* The target for this LDCONST may need output shuffling, but we assume
	 * that 'pc_ldconst' will be the LDCONST that we can patch later.  This
	 * should be the case because there's no input shuffling.  (If there's
	 * no catch clause, this LDCONST will be replaced with a NOP.)
	 */
	pc_ldconst = duk__get_current_pc(comp_ctx);
	duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, reg_catch, 0 /*patched later*/);

	pc_trycatch = duk__get_current_pc(comp_ctx);
	duk__emit_invalid(comp_ctx);  /* TRYCATCH, cannot emit now (not enough info) */
	duk__emit_invalid(comp_ctx);  /* jump for 'catch' case */
	duk__emit_invalid(comp_ctx);  /* jump for 'finally' case or end (if no finally) */

	/* try part */
	duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);
	duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/, 1 /*regexp_after*/);
	/* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
	duk__emit_op_only(comp_ctx, DUK_OP_ENDTRY);

	if (comp_ctx->curr_token.t == DUK_TOK_CATCH) {
		/*
		 *  The catch variable must be updated to reflect the new allocated
		 *  register for the duration of the catch clause.  We need to store
		 *  and restore the original value for the varmap entry (if any).
		 */

		/*
		 *  Note: currently register bindings must be fixed for the entire
		 *  function.  So, even though the catch variable is in a register
		 *  we know, we must use an explicit environment record and slow path
		 *  accesses to read/write the catch binding to make closures created
		 *  within the catch clause work correctly.  This restriction should
		 *  be fixable (at least in common cases) later.
		 *
		 *  See: test-bug-catch-binding-2.js.
		 *
		 *  XXX: improve to get fast path access to most catch clauses.
		 */

		duk_hstring *h_var;
		duk_int_t varmap_value;  /* for storing/restoring the varmap binding for catch variable */

		DUK_DDD(DUK_DDDPRINT("stack top at start of catch clause: %ld", (long) duk_get_top(thr)));

		trycatch_flags |= DUK_BC_TRYCATCH_FLAG_HAVE_CATCH;

		pc_catch = duk__get_current_pc(comp_ctx);

		duk__advance(comp_ctx);
		duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

		if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
			/* Identifier, i.e. don't allow reserved words */
			goto syntax_error;
		}
		h_var = comp_ctx->curr_token.str1;
		DUK_ASSERT(h_var != NULL);

		duk_push_hstring(thr, h_var);  /* keep in on valstack, use borrowed ref below */

		if (comp_ctx->curr_func.is_strict &&
		    ((h_var == DUK_HTHREAD_STRING_EVAL(thr)) ||
		     (h_var == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)))) {
			DUK_DDD(DUK_DDDPRINT("catch identifier 'eval' or 'arguments' in strict mode -> SyntaxError"));
			goto syntax_error;
		}

		duk_dup_top(thr);
		rc_varname = duk__getconst(comp_ctx);
		DUK_DDD(DUK_DDDPRINT("catch clause, rc_varname=0x%08lx (%ld)",
		                     (unsigned long) rc_varname, (long) rc_varname));

		duk__advance(comp_ctx);
		duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

		duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);

		DUK_DDD(DUK_DDDPRINT("varmap before modifying for catch clause: %!iT",
		                     (duk_tval *) duk_get_tval(thr, comp_ctx->curr_func.varmap_idx)));

		duk_dup_top(thr);
		duk_get_prop(thr, comp_ctx->curr_func.varmap_idx);
		if (duk_is_undefined(thr, -1)) {
			varmap_value = -2;
		} else if (duk_is_null(thr, -1)) {
			varmap_value = -1;
		} else {
			DUK_ASSERT(duk_is_number(thr, -1));
			varmap_value = duk_get_int(thr, -1);
			DUK_ASSERT(varmap_value >= 0);
		}
		duk_pop(thr);

#if 0
		/* It'd be nice to do something like this - but it doesn't
		 * work for closures created inside the catch clause.
		 */
		duk_dup_top(thr);
		duk_push_int(thr, (duk_int_t) (reg_catch + 0));
		duk_put_prop(thr, comp_ctx->curr_func.varmap_idx);
#endif
		duk_dup_top(thr);
		duk_push_null(thr);
		duk_put_prop(thr, comp_ctx->curr_func.varmap_idx);

		duk__emit_a_bc(comp_ctx,
		               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
		               reg_catch + 0 /*value*/,
		               rc_varname /*varname*/);

		DUK_DDD(DUK_DDDPRINT("varmap before parsing catch clause: %!iT",
		                     (duk_tval *) duk_get_tval(thr, comp_ctx->curr_func.varmap_idx)));

		duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/, 1 /*regexp_after*/);
		/* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */

		if (varmap_value == -2) {
			/* not present */
			duk_del_prop(thr, comp_ctx->curr_func.varmap_idx);
		} else {
			if (varmap_value == -1) {
				duk_push_null(thr);
			} else {
				DUK_ASSERT(varmap_value >= 0);
				duk_push_int(thr, varmap_value);
			}
			duk_put_prop(thr, comp_ctx->curr_func.varmap_idx);
		}
		/* varname is popped by above code */

		DUK_DDD(DUK_DDDPRINT("varmap after restore catch clause: %!iT",
		                     (duk_tval *) duk_get_tval(thr, comp_ctx->curr_func.varmap_idx)));

		duk__emit_op_only(comp_ctx,
		                  DUK_OP_ENDCATCH);

		/*
		 *  XXX: for now, indicate that an expensive catch binding
		 *  declarative environment is always needed.  If we don't
		 *  need it, we don't need the const_varname either.
		 */

		trycatch_flags |= DUK_BC_TRYCATCH_FLAG_CATCH_BINDING;

		DUK_DDD(DUK_DDDPRINT("stack top at end of catch clause: %ld", (long) duk_get_top(thr)));
	}

	if (comp_ctx->curr_token.t == DUK_TOK_FINALLY) {
		trycatch_flags |= DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY;

		pc_finally = duk__get_current_pc(comp_ctx);

		duk__advance(comp_ctx);

		duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);
		duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/, 1 /*regexp_after*/);
		/* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
		duk__emit_abc(comp_ctx,
		              DUK_OP_ENDFIN,
		              reg_catch);  /* rethrow */
	}

	if (!(trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH) &&
	    !(trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY)) {
		/* must have catch and/or finally */
		goto syntax_error;
	}

	/* If there's no catch block, rc_varname will be 0 and duk__patch_trycatch()
	 * will replace the LDCONST with a NOP.  For any actual constant (including
	 * constant 0) the DUK__CONST_MARKER flag will be set in rc_varname.
	 */

	duk__patch_trycatch(comp_ctx,
	                    pc_ldconst,
	                    pc_trycatch,
	                    reg_catch,
	                    rc_varname,
	                    trycatch_flags);

	if (trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH) {
		DUK_ASSERT(pc_catch >= 0);
		duk__patch_jump(comp_ctx, pc_trycatch + 1, pc_catch);
	}

	if (trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY) {
		DUK_ASSERT(pc_finally >= 0);
		duk__patch_jump(comp_ctx, pc_trycatch + 2, pc_finally);
	} else {
		/* without finally, the second jump slot is used to jump to end of stmt */
		duk__patch_jump_here(comp_ctx, pc_trycatch + 2);
	}

	comp_ctx->curr_func.catch_depth--;
	return;

 syntax_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_TRY);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__parse_with_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
	duk_int_t pc_trycatch;
	duk_int_t pc_finished;
	duk_regconst_t reg_catch;
	duk_small_uint_t trycatch_flags;

	if (comp_ctx->curr_func.is_strict) {
		DUK_ERROR_SYNTAX(comp_ctx->thr, DUK_STR_WITH_IN_STRICT_MODE);
		DUK_WO_NORETURN(return;);
	}

	comp_ctx->curr_func.catch_depth++;

	duk__advance(comp_ctx);  /* eat 'with' */

	reg_catch = DUK__ALLOCTEMPS(comp_ctx, 2);

	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);
	duk__exprtop_toforcedreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/, reg_catch);
	comp_ctx->curr_func.allow_regexp_in_adv = 1;
	duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);  /* Allow RegExp as part of next stmt. */

	pc_trycatch = duk__get_current_pc(comp_ctx);
	trycatch_flags = DUK_BC_TRYCATCH_FLAG_WITH_BINDING;
	duk__emit_a_bc(comp_ctx,
	                DUK_OP_TRYCATCH | DUK__EMIT_FLAG_NO_SHUFFLE_A,
	                (duk_regconst_t) trycatch_flags /*a*/,
	                reg_catch /*bc*/);
	duk__emit_invalid(comp_ctx);  /* catch jump */
	duk__emit_invalid(comp_ctx);  /* finished jump */

	duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
	duk__emit_op_only(comp_ctx, DUK_OP_ENDTRY);

	pc_finished = duk__get_current_pc(comp_ctx);

	duk__patch_jump(comp_ctx, pc_trycatch + 2, pc_finished);

	comp_ctx->curr_func.catch_depth--;
}

DUK_LOCAL duk_int_t duk__stmt_label_site(duk_compiler_ctx *comp_ctx, duk_int_t label_id) {
	/* if a site already exists, nop: max one label site per statement */
	if (label_id >= 0) {
		return label_id;
	}

	label_id = comp_ctx->curr_func.label_next++;
	DUK_DDD(DUK_DDDPRINT("allocated new label id for label site: %ld", (long) label_id));

	duk__emit_bc(comp_ctx,
	             DUK_OP_LABEL,
	             (duk_regconst_t) label_id);
	duk__emit_invalid(comp_ctx);
	duk__emit_invalid(comp_ctx);

	return label_id;
}

/* Parse a single statement.
 *
 * Creates a label site (with an empty label) automatically for iteration
 * statements.  Also "peels off" any label statements for explicit labels.
 */
DUK_LOCAL void duk__parse_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_bool_t allow_source_elem) {
	duk_hthread *thr = comp_ctx->thr;
	duk_bool_t dir_prol_at_entry;    /* directive prologue status at entry */
	duk_regconst_t temp_at_entry;
	duk_size_t labels_len_at_entry;
	duk_int_t pc_at_entry;           /* assumed to also be PC of "LABEL" */
	duk_int_t stmt_id;
	duk_small_uint_t stmt_flags = 0;
	duk_int_t label_id = -1;
	duk_small_uint_t tok;
	duk_bool_t test_func_decl;

	DUK__RECURSION_INCREASE(comp_ctx, thr);

	temp_at_entry = DUK__GETTEMP(comp_ctx);
	pc_at_entry = duk__get_current_pc(comp_ctx);
	labels_len_at_entry = duk_get_length(thr, comp_ctx->curr_func.labelnames_idx);
	stmt_id = comp_ctx->curr_func.stmt_next++;
	dir_prol_at_entry = comp_ctx->curr_func.in_directive_prologue;

	DUK_UNREF(stmt_id);

	DUK_DDD(DUK_DDDPRINT("parsing a statement, stmt_id=%ld, temp_at_entry=%ld, labels_len_at_entry=%ld, "
	                     "is_strict=%ld, in_directive_prologue=%ld, catch_depth=%ld",
	                     (long) stmt_id, (long) temp_at_entry, (long) labels_len_at_entry,
	                     (long) comp_ctx->curr_func.is_strict, (long) comp_ctx->curr_func.in_directive_prologue,
	                     (long) comp_ctx->curr_func.catch_depth));

	/* The directive prologue flag is cleared by default so that it is
	 * unset for any recursive statement parsing.  It is only "revived"
	 * if a directive is detected.  (We could also make directives only
	 * allowed if 'allow_source_elem' was true.)
	 */
	comp_ctx->curr_func.in_directive_prologue = 0;

 retry_parse:

	DUK_DDD(DUK_DDDPRINT("try stmt parse, stmt_id=%ld, label_id=%ld, allow_source_elem=%ld, catch_depth=%ld",
	                     (long) stmt_id, (long) label_id, (long) allow_source_elem,
	                     (long) comp_ctx->curr_func.catch_depth));

	/*
	 *  Detect iteration statements; if encountered, establish an
	 *  empty label.
	 */

	tok = comp_ctx->curr_token.t;
	if (tok == DUK_TOK_FOR || tok == DUK_TOK_DO || tok == DUK_TOK_WHILE ||
	    tok == DUK_TOK_SWITCH) {
		DUK_DDD(DUK_DDDPRINT("iteration/switch statement -> add empty label"));

		label_id = duk__stmt_label_site(comp_ctx, label_id);
		duk__add_label(comp_ctx,
		               DUK_HTHREAD_STRING_EMPTY_STRING(thr),
		               pc_at_entry /*pc_label*/,
		               label_id);
	}

	/*
	 *  Main switch for statement / source element type.
	 */

	switch (comp_ctx->curr_token.t) {
	case DUK_TOK_FUNCTION: {
		/*
		 *  Function declaration, function expression, or (non-standard)
		 *  function statement.
		 *
		 *  The E5 specification only allows function declarations at
		 *  the top level (in "source elements").  An ExpressionStatement
		 *  is explicitly not allowed to begin with a "function" keyword
		 *  (E5 Section 12.4).  Hence any non-error semantics for such
		 *  non-top-level statements are non-standard.  Duktape semantics
		 *  for function statements are modelled after V8, see
		 *  test-dev-func-decl-outside-top.js.
		 */
		test_func_decl = allow_source_elem;
#if defined(DUK_USE_NONSTD_FUNC_STMT)
		/* Lenient: allow function declarations outside top level in
		 * non-strict mode but reject them in strict mode.
		 */
		test_func_decl = test_func_decl || !comp_ctx->curr_func.is_strict;
#endif  /* DUK_USE_NONSTD_FUNC_STMT */
		/* Strict: never allow function declarations outside top level. */
		if (test_func_decl) {
			/* FunctionDeclaration: not strictly a statement but handled as such.
			 *
			 * O(depth^2) parse count for inner functions is handled by recording a
			 * lexer offset on the first compilation pass, so that the function can
			 * be efficiently skipped on the second pass.  This is encapsulated into
			 * duk__parse_func_like_fnum().
			 */

			duk_int_t fnum;
#if defined(DUK_USE_ASSERTIONS)
			duk_idx_t top_before;
#endif

			DUK_DDD(DUK_DDDPRINT("function declaration statement"));

#if defined(DUK_USE_ASSERTIONS)
			top_before = duk_get_top(thr);
#endif

			duk__advance(comp_ctx);  /* eat 'function' */
			fnum = duk__parse_func_like_fnum(comp_ctx, DUK__FUNC_FLAG_DECL | DUK__FUNC_FLAG_PUSHNAME_PASS1);

			/* The value stack convention here is a bit odd: the function
			 * name is only pushed on pass 1 (in_scanning), and is needed
			 * to process function declarations.
			 */
			if (comp_ctx->curr_func.in_scanning) {
				duk_uarridx_t n;

#if defined(DUK_USE_ASSERTIONS)
				DUK_ASSERT(duk_get_top(thr) == top_before + 1);
#endif
				DUK_DDD(DUK_DDDPRINT("register function declaration %!T in pass 1, fnum %ld",
				                     duk_get_tval(thr, -1), (long) fnum));
				n = (duk_uarridx_t) duk_get_length(thr, comp_ctx->curr_func.decls_idx);
				/* funcname is at index -1 */
				duk_put_prop_index(thr, comp_ctx->curr_func.decls_idx, n);
				duk_push_int(thr, (duk_int_t) (DUK_DECL_TYPE_FUNC + (fnum << 8)));
				duk_put_prop_index(thr, comp_ctx->curr_func.decls_idx, n + 1);
			} else {
#if defined(DUK_USE_ASSERTIONS)
				DUK_ASSERT(duk_get_top(thr) == top_before);
#endif
			}

			/* no statement value (unlike function expression) */
			stmt_flags = 0;
			break;
		} else {
			DUK_ERROR_SYNTAX(thr, DUK_STR_FUNC_STMT_NOT_ALLOWED);
			DUK_WO_NORETURN(return;);
		}
		break;
	}
	case DUK_TOK_LCURLY: {
		DUK_DDD(DUK_DDDPRINT("block statement"));
		duk__advance(comp_ctx);
		duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/, 1 /*regexp_after*/);
		/* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
		if (label_id >= 0) {
			duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
		}
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_CONST: {
		DUK_DDD(DUK_DDDPRINT("constant declaration statement"));
		duk__parse_var_stmt(comp_ctx, res, DUK__EXPR_FLAG_REQUIRE_INIT /*expr_flags*/);
		stmt_flags = DUK__HAS_TERM;
		break;
	}
	case DUK_TOK_VAR: {
		DUK_DDD(DUK_DDDPRINT("variable declaration statement"));
		duk__parse_var_stmt(comp_ctx, res, 0 /*expr_flags*/);
		stmt_flags = DUK__HAS_TERM;
		break;
	}
	case DUK_TOK_SEMICOLON: {
		/* empty statement with an explicit semicolon */
		DUK_DDD(DUK_DDDPRINT("empty statement"));
		stmt_flags = DUK__HAS_TERM;
		break;
	}
	case DUK_TOK_IF: {
		DUK_DDD(DUK_DDDPRINT("if statement"));
		duk__parse_if_stmt(comp_ctx, res);
		if (label_id >= 0) {
			duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
		}
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_DO: {
		/*
		 *  Do-while statement is mostly trivial, but there is special
		 *  handling for automatic semicolon handling (triggered by the
		 *  DUK__ALLOW_AUTO_SEMI_ALWAYS) flag related to a bug filed at:
		 *
		 *    https://bugs.ecmascript.org/show_bug.cgi?id=8
		 *
		 *  See doc/compiler.rst for details.
		 */
		DUK_DDD(DUK_DDDPRINT("do statement"));
		DUK_ASSERT(label_id >= 0);
		duk__update_label_flags(comp_ctx,
		                        label_id,
		                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
		duk__parse_do_stmt(comp_ctx, res, pc_at_entry);
		stmt_flags = DUK__HAS_TERM | DUK__ALLOW_AUTO_SEMI_ALWAYS;  /* DUK__ALLOW_AUTO_SEMI_ALWAYS workaround */
		break;
	}
	case DUK_TOK_WHILE: {
		DUK_DDD(DUK_DDDPRINT("while statement"));
		DUK_ASSERT(label_id >= 0);
		duk__update_label_flags(comp_ctx,
		                        label_id,
		                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
		duk__parse_while_stmt(comp_ctx, res, pc_at_entry);
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_FOR: {
		/*
		 *  For/for-in statement is complicated to parse because
		 *  determining the statement type (three-part for vs. a
		 *  for-in) requires potential backtracking.
		 *
		 *  See the helper for the messy stuff.
		 */
		DUK_DDD(DUK_DDDPRINT("for/for-in statement"));
		DUK_ASSERT(label_id >= 0);
		duk__update_label_flags(comp_ctx,
		                        label_id,
		                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
		duk__parse_for_stmt(comp_ctx, res, pc_at_entry);
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_CONTINUE:
	case DUK_TOK_BREAK: {
		DUK_DDD(DUK_DDDPRINT("break/continue statement"));
		duk__parse_break_or_continue_stmt(comp_ctx, res);
		stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
		break;
	}
	case DUK_TOK_RETURN: {
		DUK_DDD(DUK_DDDPRINT("return statement"));
		duk__parse_return_stmt(comp_ctx, res);
		stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
		break;
	}
	case DUK_TOK_WITH: {
		DUK_DDD(DUK_DDDPRINT("with statement"));
		comp_ctx->curr_func.with_depth++;
		duk__parse_with_stmt(comp_ctx, res);
		if (label_id >= 0) {
			duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
		}
		comp_ctx->curr_func.with_depth--;
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_SWITCH: {
		/*
		 *  The switch statement is pretty messy to compile.
		 *  See the helper for details.
		 */
		DUK_DDD(DUK_DDDPRINT("switch statement"));
		DUK_ASSERT(label_id >= 0);
		duk__update_label_flags(comp_ctx,
		                        label_id,
		                        DUK_LABEL_FLAG_ALLOW_BREAK);  /* don't allow continue */
		duk__parse_switch_stmt(comp_ctx, res, pc_at_entry);
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_THROW: {
		DUK_DDD(DUK_DDDPRINT("throw statement"));
		duk__parse_throw_stmt(comp_ctx, res);
		stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
		break;
	}
	case DUK_TOK_TRY: {
		DUK_DDD(DUK_DDDPRINT("try statement"));
		duk__parse_try_stmt(comp_ctx, res);
		stmt_flags = 0;
		break;
	}
	case DUK_TOK_DEBUGGER: {
		duk__advance(comp_ctx);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
		DUK_DDD(DUK_DDDPRINT("debugger statement: debugging enabled, emit debugger opcode"));
		duk__emit_op_only(comp_ctx, DUK_OP_DEBUGGER);
#else
		DUK_DDD(DUK_DDDPRINT("debugger statement: ignored"));
#endif
		stmt_flags = DUK__HAS_TERM;
		break;
	}
	default: {
		/*
		 *  Else, must be one of:
		 *    - ExpressionStatement, possibly a directive (String)
		 *    - LabelledStatement (Identifier followed by ':')
		 *
		 *  Expressions beginning with 'function' keyword are covered by a case
		 *  above (such expressions are not allowed in standard E5 anyway).
		 *  Also expressions starting with '{' are interpreted as block
		 *  statements.  See E5 Section 12.4.
		 *
		 *  Directive detection is tricky; see E5 Section 14.1 on directive
		 *  prologue.  A directive is an expression statement with a single
		 *  string literal and an explicit or automatic semicolon.  Escape
		 *  characters are significant and no parens etc are allowed:
		 *
		 *    'use strict';          // valid 'use strict' directive
		 *    'use\u0020strict';     // valid directive, not a 'use strict' directive
		 *    ('use strict');        // not a valid directive
		 *
		 *  The expression is determined to consist of a single string literal
		 *  based on duk__expr_nud() and duk__expr_led() call counts.  The string literal
		 *  of a 'use strict' directive is determined to lack any escapes based
		 *  num_escapes count from the lexer.  Note that other directives may be
		 *  allowed to contain escapes, so a directive with escapes does not
		 *  terminate a directive prologue.
		 *
		 *  We rely on the fact that the expression parser will not emit any
		 *  code for a single token expression.  However, it will generate an
		 *  intermediate value which we will then successfully ignore.
		 *
		 *  A similar approach is used for labels.
		 */

		duk_bool_t single_token;

		DUK_DDD(DUK_DDDPRINT("expression statement"));
		duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);

		single_token = (comp_ctx->curr_func.nud_count == 1 &&  /* one token */
		                comp_ctx->curr_func.led_count == 0);   /* no operators */

		if (single_token &&
		    comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
		    comp_ctx->curr_token.t == DUK_TOK_COLON) {
			/*
			 *  Detected label
			 */

			duk_hstring *h_lab;

			/* expected ival */
			DUK_ASSERT(res->t == DUK_IVAL_VAR);
			DUK_ASSERT(res->x1.t == DUK_ISPEC_VALUE);
			DUK_ASSERT(DUK_TVAL_IS_STRING(duk_get_tval(thr, res->x1.valstack_idx)));
			h_lab = comp_ctx->prev_token.str1;
			DUK_ASSERT(h_lab != NULL);

			DUK_DDD(DUK_DDDPRINT("explicit label site for label '%!O'",
			                     (duk_heaphdr *) h_lab));

			duk__advance(comp_ctx);  /* eat colon */

			label_id = duk__stmt_label_site(comp_ctx, label_id);

			duk__add_label(comp_ctx,
			               h_lab,
			               pc_at_entry /*pc_label*/,
			               label_id);

			/* a statement following a label cannot be a source element
			 * (a function declaration).
			 */
			allow_source_elem = 0;

			DUK_DDD(DUK_DDDPRINT("label handled, retry statement parsing"));
			goto retry_parse;
		}

		stmt_flags = 0;

		if (dir_prol_at_entry &&                           /* still in prologue */
		    single_token &&                                /* single string token */
		    comp_ctx->prev_token.t == DUK_TOK_STRING) {
			/*
			 *  Detected a directive
			 */
			duk_hstring *h_dir;

			/* expected ival */
			DUK_ASSERT(res->t == DUK_IVAL_PLAIN);
			DUK_ASSERT(res->x1.t == DUK_ISPEC_VALUE);
			DUK_ASSERT(DUK_TVAL_IS_STRING(duk_get_tval(thr, res->x1.valstack_idx)));
			h_dir = comp_ctx->prev_token.str1;
			DUK_ASSERT(h_dir != NULL);

			DUK_DDD(DUK_DDDPRINT("potential directive: %!O", h_dir));

			stmt_flags |= DUK__STILL_PROLOGUE;

			/* Note: escaped characters differentiate directives */

			if (comp_ctx->prev_token.num_escapes > 0) {
				DUK_DDD(DUK_DDDPRINT("directive contains escapes: valid directive "
				                     "but we ignore such directives"));
			} else {
				/*
				 * The length comparisons are present to handle
				 * strings like "use strict\u0000foo" as required.
				 */

				if (DUK_HSTRING_GET_BYTELEN(h_dir) == 10 &&
				    DUK_STRCMP((const char *) DUK_HSTRING_GET_DATA(h_dir), "use strict") == 0) {
#if defined(DUK_USE_STRICT_DECL)
					DUK_DDD(DUK_DDDPRINT("use strict directive detected: strict flag %ld -> %ld",
					                     (long) comp_ctx->curr_func.is_strict, (long) 1));
					comp_ctx->curr_func.is_strict = 1;
#else
					DUK_DDD(DUK_DDDPRINT("use strict detected but strict declarations disabled, ignoring"));
#endif
				} else if (DUK_HSTRING_GET_BYTELEN(h_dir) == 14 &&
				           DUK_STRCMP((const char *) DUK_HSTRING_GET_DATA(h_dir), "use duk notail") == 0) {
					DUK_DDD(DUK_DDDPRINT("use duk notail directive detected: notail flag %ld -> %ld",
					                     (long) comp_ctx->curr_func.is_notail, (long) 1));
					comp_ctx->curr_func.is_notail = 1;
				} else {
					DUK_DD(DUK_DDPRINT("unknown directive: '%!O', ignoring but not terminating "
					                   "directive prologue", (duk_hobject *) h_dir));
				}
			}
		} else {
			DUK_DDD(DUK_DDDPRINT("non-directive expression statement or no longer in prologue; "
			                     "prologue terminated if still active"));
                }

		stmt_flags |= DUK__HAS_VAL | DUK__HAS_TERM;
	}
	}  /* end switch (tok) */

	/*
	 *  Statement value handling.
	 *
	 *  Global code and eval code has an implicit return value
	 *  which comes from the last statement with a value
	 *  (technically a non-"empty" continuation, which is
	 *  different from an empty statement).
	 *
	 *  Since we don't know whether a later statement will
	 *  override the value of the current statement, we need
	 *  to coerce the statement value to a register allocated
	 *  for implicit return values.  In other cases we need
	 *  to coerce the statement value to a plain value to get
	 *  any side effects out (consider e.g. "foo.bar;").
	 */

	/* XXX: what about statements which leave a half-cooked value in 'res'
	 * but have no stmt value?  Any such statements?
	 */

	if (stmt_flags & DUK__HAS_VAL) {
		duk_regconst_t reg_stmt_value = comp_ctx->curr_func.reg_stmt_value;
		if (reg_stmt_value >= 0) {
			duk__ivalue_toforcedreg(comp_ctx, res, reg_stmt_value);
		} else {
			duk__ivalue_toplain_ignore(comp_ctx, res);
		}
	} else {
		;
	}

	/*
	 *  Statement terminator check, including automatic semicolon
	 *  handling.  After this step, 'curr_tok' should be the first
	 *  token after a possible statement terminator.
	 */

	if (stmt_flags & DUK__HAS_TERM) {
		if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON) {
			DUK_DDD(DUK_DDDPRINT("explicit semicolon terminates statement"));
			duk__advance(comp_ctx);
		} else {
			if (comp_ctx->curr_token.allow_auto_semi) {
				DUK_DDD(DUK_DDDPRINT("automatic semicolon terminates statement"));
			} else if (stmt_flags & DUK__ALLOW_AUTO_SEMI_ALWAYS) {
				/* XXX: make this lenience dependent on flags or strictness? */
				DUK_DDD(DUK_DDDPRINT("automatic semicolon terminates statement (allowed for compatibility "
				                     "even though no lineterm present before next token)"));
			} else {
				DUK_ERROR_SYNTAX(thr, DUK_STR_UNTERMINATED_STMT);
				DUK_WO_NORETURN(return;);
			}
		}
	} else {
		DUK_DDD(DUK_DDDPRINT("statement has no terminator"));
	}

	/*
	 *  Directive prologue tracking.
	 */

	if (stmt_flags & DUK__STILL_PROLOGUE) {
		DUK_DDD(DUK_DDDPRINT("setting in_directive_prologue"));
		comp_ctx->curr_func.in_directive_prologue = 1;
	}

	/*
	 *  Cleanups (all statement parsing flows through here).
	 *
	 *  Pop label site and reset labels.  Reset 'next temp' to value at
	 *  entry to reuse temps.
	 */

	if (label_id >= 0) {
		duk__emit_bc(comp_ctx,
		             DUK_OP_ENDLABEL,
		             (duk_regconst_t) label_id);
	}

	DUK__SETTEMP(comp_ctx, temp_at_entry);

	duk__reset_labels_to_length(comp_ctx, labels_len_at_entry);

	/* XXX: return indication of "terminalness" (e.g. a 'throw' is terminal) */

	DUK__RECURSION_DECREASE(comp_ctx, thr);
}

/*
 *  Parse a statement list.
 *
 *  Handles automatic semicolon insertion and implicit return value.
 *
 *  Upon entry, 'curr_tok' should contain the first token of the first
 *  statement (parsed in the "allow regexp literal" mode).  Upon exit,
 *  'curr_tok' contains the token following the statement list terminator
 *  (EOF or closing brace).
 */

DUK_LOCAL void duk__parse_stmts(duk_compiler_ctx *comp_ctx, duk_bool_t allow_source_elem, duk_bool_t expect_eof, duk_bool_t regexp_after) {
	duk_hthread *thr = comp_ctx->thr;
	duk_ivalue res_alloc;
	duk_ivalue *res = &res_alloc;

	/* Setup state.  Initial ivalue is 'undefined'. */

	duk_require_stack(thr, DUK__PARSE_STATEMENTS_SLOTS);

	/* XXX: 'res' setup can be moved to function body level; in fact, two 'res'
	 * intermediate values suffice for parsing of each function.  Nesting is needed
	 * for nested functions (which may occur inside expressions).
	 */

	duk_memzero(&res_alloc, sizeof(res_alloc));
	res->t = DUK_IVAL_PLAIN;
	res->x1.t = DUK_ISPEC_VALUE;
	res->x1.valstack_idx = duk_get_top(thr);
	res->x2.valstack_idx = res->x1.valstack_idx + 1;
	duk_push_undefined(thr);
	duk_push_undefined(thr);

	/* Parse statements until a closing token (EOF or '}') is found. */

	for (;;) {
		/* Check whether statement list ends. */

		if (expect_eof) {
			if (comp_ctx->curr_token.t == DUK_TOK_EOF) {
				break;
			}
		} else {
			if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
				break;
			}
		}

		/* Check statement type based on the first token type.
		 *
		 * Note: expression parsing helpers expect 'curr_tok' to
		 * contain the first token of the expression upon entry.
		 */

		DUK_DDD(DUK_DDDPRINT("TOKEN %ld (non-whitespace, non-comment)", (long) comp_ctx->curr_token.t));

		duk__parse_stmt(comp_ctx, res, allow_source_elem);
	}

	/* RegExp is allowed / not allowed depending on context.  For function
	 * declarations RegExp is allowed because it follows a function
	 * declaration statement and may appear as part of the next statement.
	 * For function expressions RegExp is not allowed, and it's possible
	 * to do something like '(function () {} / 123)'.
	 */
	if (regexp_after) {
		comp_ctx->curr_func.allow_regexp_in_adv = 1;
	}
	duk__advance(comp_ctx);

	/* Tear down state. */

	duk_pop_2(thr);
}

/*
 *  Declaration binding instantiation conceptually happens when calling a
 *  function; for us it essentially means that function prologue.  The
 *  conceptual process is described in E5 Section 10.5.
 *
 *  We need to keep track of all encountered identifiers to (1) create an
 *  identifier-to-register map ("varmap"); and (2) detect duplicate
 *  declarations.  Identifiers which are not bound to registers still need
 *  to be tracked for detecting duplicates.  Currently such identifiers
 *  are put into the varmap with a 'null' value, which is later cleaned up.
 *
 *  To support functions with a large number of variable and function
 *  declarations, registers are not allocated beyond a certain limit;
 *  after that limit, variables and functions need slow path access.
 *  Arguments are currently always register bound, which imposes a hard
 *  (and relatively small) argument count limit.
 *
 *  Some bindings in E5 are not configurable (= deletable) and almost all
 *  are mutable (writable).  Exceptions are:
 *
 *    - The 'arguments' binding, established only if no shadowing argument
 *      or function declaration exists.  We handle 'arguments' creation
 *      and binding through an explicit slow path environment record.
 *
 *    - The "name" binding for a named function expression.  This is also
 *      handled through an explicit slow path environment record.
 */

/* XXX: add support for variables to not be register bound always, to
 * handle cases with a very large number of variables?
 */

DUK_LOCAL void duk__init_varmap_and_prologue_for_pass2(duk_compiler_ctx *comp_ctx, duk_regconst_t *out_stmt_value_reg) {
	duk_hthread *thr = comp_ctx->thr;
	duk_hstring *h_name;
	duk_bool_t configurable_bindings;
	duk_uarridx_t num_args;
	duk_uarridx_t num_decls;
	duk_regconst_t rc_name;
	duk_small_uint_t declvar_flags;
	duk_uarridx_t i;
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t entry_top;
#endif

#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(thr);
#endif

	/*
	 *  Preliminaries
	 */

	configurable_bindings = comp_ctx->curr_func.is_eval;
	DUK_DDD(DUK_DDDPRINT("configurable_bindings=%ld", (long) configurable_bindings));

	/* varmap is already in comp_ctx->curr_func.varmap_idx */

	/*
	 *  Function formal arguments, always bound to registers
	 *  (there's no support for shuffling them now).
	 */

	num_args = (duk_uarridx_t) duk_get_length(thr, comp_ctx->curr_func.argnames_idx);
	DUK_DDD(DUK_DDDPRINT("num_args=%ld", (long) num_args));
	/* XXX: check num_args */

	for (i = 0; i < num_args; i++) {
		duk_get_prop_index(thr, comp_ctx->curr_func.argnames_idx, i);
		h_name = duk_known_hstring(thr, -1);

		if (comp_ctx->curr_func.is_strict) {
			if (duk__hstring_is_eval_or_arguments(comp_ctx, h_name)) {
				DUK_DDD(DUK_DDDPRINT("arg named 'eval' or 'arguments' in strict mode -> SyntaxError"));
				goto error_argname;
			}
			duk_dup_top(thr);
			if (duk_has_prop(thr, comp_ctx->curr_func.varmap_idx)) {
				DUK_DDD(DUK_DDDPRINT("duplicate arg name in strict mode -> SyntaxError"));
				goto error_argname;
			}

			/* Ensure argument name is not a reserved word in current
			 * (final) strictness.  Formal argument parsing may not
			 * catch reserved names if strictness changes during
			 * parsing.
			 *
			 * We only need to do this in strict mode because non-strict
			 * keyword are always detected in formal argument parsing.
			 */

			if (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(h_name)) {
				goto error_argname;
			}
		}

		/* overwrite any previous binding of the same name; the effect is
		 * that last argument of a certain name wins.
		 */

		/* only functions can have arguments */
		DUK_ASSERT(comp_ctx->curr_func.is_function);
		duk_push_uarridx(thr, i);  /* -> [ ... name index ] */
		duk_put_prop(thr, comp_ctx->curr_func.varmap_idx); /* -> [ ... ] */

		/* no code needs to be emitted, the regs already have values */
	}

	/* use temp_next for tracking register allocations */
	DUK__SETTEMP_CHECKMAX(comp_ctx, (duk_regconst_t) num_args);

	/*
	 *  After arguments, allocate special registers (like shuffling temps)
	 */

	if (out_stmt_value_reg) {
		*out_stmt_value_reg = DUK__ALLOCTEMP(comp_ctx);
	}
	if (comp_ctx->curr_func.needs_shuffle) {
		duk_regconst_t shuffle_base = DUK__ALLOCTEMPS(comp_ctx, 3);
		comp_ctx->curr_func.shuffle1 = shuffle_base;
		comp_ctx->curr_func.shuffle2 = shuffle_base + 1;
		comp_ctx->curr_func.shuffle3 = shuffle_base + 2;
		DUK_D(DUK_DPRINT("shuffle registers needed by function, allocated: %ld %ld %ld",
		                 (long) comp_ctx->curr_func.shuffle1,
		                 (long) comp_ctx->curr_func.shuffle2,
		                 (long) comp_ctx->curr_func.shuffle3));
	}
	if (comp_ctx->curr_func.temp_next > 0x100) {
		DUK_D(DUK_DPRINT("not enough 8-bit regs: temp_next=%ld", (long) comp_ctx->curr_func.temp_next));
		goto error_outofregs;
	}

	/*
	 *  Function declarations
	 */

	num_decls = (duk_uarridx_t) duk_get_length(thr, comp_ctx->curr_func.decls_idx);
	DUK_DDD(DUK_DDDPRINT("num_decls=%ld -> %!T",
	                     (long) num_decls,
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->curr_func.decls_idx)));
	for (i = 0; i < num_decls; i += 2) {
		duk_int_t decl_type;
		duk_int_t fnum;

		duk_get_prop_index(thr, comp_ctx->curr_func.decls_idx, i + 1);  /* decl type */
		decl_type = duk_to_int(thr, -1);
		fnum = decl_type >> 8;  /* XXX: macros */
		decl_type = decl_type & 0xff;
		duk_pop(thr);

		if (decl_type != DUK_DECL_TYPE_FUNC) {
			continue;
		}

		duk_get_prop_index(thr, comp_ctx->curr_func.decls_idx, i);  /* decl name */

		/* XXX: spilling */
		if (comp_ctx->curr_func.is_function) {
			duk_regconst_t reg_bind;
			duk_dup_top(thr);
			if (duk_has_prop(thr, comp_ctx->curr_func.varmap_idx)) {
				/* shadowed; update value */
				duk_dup_top(thr);
				duk_get_prop(thr, comp_ctx->curr_func.varmap_idx);
				reg_bind = duk_to_int(thr, -1);  /* [ ... name reg_bind ] */
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_CLOSURE,
				               reg_bind,
				               (duk_regconst_t) fnum);
			} else {
				/* function: always register bound */
				reg_bind = DUK__ALLOCTEMP(comp_ctx);
				duk__emit_a_bc(comp_ctx,
				               DUK_OP_CLOSURE,
				               reg_bind,
				               (duk_regconst_t) fnum);
				duk_push_int(thr, (duk_int_t) reg_bind);
			}
		} else {
			/* Function declaration for global/eval code is emitted even
			 * for duplicates, because of E5 Section 10.5, step 5.e of
			 * E5.1 (special behavior for variable bound to global object).
			 *
			 * DECLVAR will not re-declare a variable as such, but will
			 * update the binding value.
			 */

			duk_regconst_t reg_temp = DUK__ALLOCTEMP(comp_ctx);
			duk_dup_top(thr);
			rc_name = duk__getconst(comp_ctx);
			duk_push_null(thr);

			duk__emit_a_bc(comp_ctx,
			               DUK_OP_CLOSURE,
			               reg_temp,
			               (duk_regconst_t) fnum);

			declvar_flags = DUK_PROPDESC_FLAG_WRITABLE |
			                DUK_PROPDESC_FLAG_ENUMERABLE |
			                DUK_BC_DECLVAR_FLAG_FUNC_DECL;

			if (configurable_bindings) {
				declvar_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
			}

			duk__emit_a_b_c(comp_ctx,
			                DUK_OP_DECLVAR | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_BC_REGCONST,
			                (duk_regconst_t) declvar_flags /*flags*/,
			                rc_name /*name*/,
			                reg_temp /*value*/);

			DUK__SETTEMP(comp_ctx, reg_temp);  /* forget temp */
		}

		DUK_DDD(DUK_DDDPRINT("function declaration to varmap: %!T -> %!T",
		                     (duk_tval *) duk_get_tval(thr, -2),
		                     (duk_tval *) duk_get_tval(thr, -1)));

#if defined(DUK_USE_FASTINT)
		DUK_ASSERT(DUK_TVAL_IS_NULL(duk_get_tval(thr, -1)) || DUK_TVAL_IS_FASTINT(duk_get_tval(thr, -1)));
#endif
		duk_put_prop(thr, comp_ctx->curr_func.varmap_idx);  /* [ ... name reg/null ] -> [ ... ] */
	}

	/*
	 *  'arguments' binding is special; if a shadowing argument or
	 *  function declaration exists, an arguments object will
	 *  definitely not be needed, regardless of whether the identifier
	 *  'arguments' is referenced inside the function body.
	 */

	if (duk_has_prop_stridx(thr, comp_ctx->curr_func.varmap_idx, DUK_STRIDX_LC_ARGUMENTS)) {
		DUK_DDD(DUK_DDDPRINT("'arguments' is shadowed by argument or function declaration "
		                     "-> arguments object creation can be skipped"));
		comp_ctx->curr_func.is_arguments_shadowed = 1;
	}

	/*
	 *  Variable declarations.
	 *
	 *  Unlike function declarations, variable declaration values don't get
	 *  assigned on entry.  If a binding of the same name already exists, just
	 *  ignore it silently.
	 */

	for (i = 0; i < num_decls; i += 2) {
		duk_int_t decl_type;

		duk_get_prop_index(thr, comp_ctx->curr_func.decls_idx, i + 1);  /* decl type */
		decl_type = duk_to_int(thr, -1);
		decl_type = decl_type & 0xff;
		duk_pop(thr);

		if (decl_type != DUK_DECL_TYPE_VAR) {
			continue;
		}

		duk_get_prop_index(thr, comp_ctx->curr_func.decls_idx, i);  /* decl name */

		if (duk_has_prop(thr, comp_ctx->curr_func.varmap_idx)) {
			/* shadowed, ignore */
		} else {
			duk_get_prop_index(thr, comp_ctx->curr_func.decls_idx, i);  /* decl name */
			h_name = duk_known_hstring(thr, -1);

			if (h_name == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr) &&
			    !comp_ctx->curr_func.is_arguments_shadowed) {
				/* E5 Section steps 7-8 */
				DUK_DDD(DUK_DDDPRINT("'arguments' not shadowed by a function declaration, "
				                     "but appears as a variable declaration -> treat as "
				                     "a no-op for variable declaration purposes"));
				duk_pop(thr);
				continue;
			}

			/* XXX: spilling */
			if (comp_ctx->curr_func.is_function) {
				duk_regconst_t reg_bind = DUK__ALLOCTEMP(comp_ctx);
				/* no need to init reg, it will be undefined on entry */
				duk_push_int(thr, (duk_int_t) reg_bind);
			} else {
				duk_dup_top(thr);
				rc_name = duk__getconst(comp_ctx);
				duk_push_null(thr);

				declvar_flags = DUK_PROPDESC_FLAG_WRITABLE |
			                        DUK_PROPDESC_FLAG_ENUMERABLE;
				if (configurable_bindings) {
					declvar_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
				}

				duk__emit_a_b_c(comp_ctx,
				                DUK_OP_DECLVAR | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_BC_REGCONST,
				                (duk_regconst_t) declvar_flags /*flags*/,
				                rc_name /*name*/,
				                0 /*value*/);
			}

			duk_put_prop(thr, comp_ctx->curr_func.varmap_idx);  /* [ ... name reg/null ] -> [ ... ] */
		}
	}

	/*
	 *  Wrap up
	 */

	DUK_DDD(DUK_DDDPRINT("varmap: %!T, is_arguments_shadowed=%ld",
	                     (duk_tval *) duk_get_tval(thr, comp_ctx->curr_func.varmap_idx),
	                     (long) comp_ctx->curr_func.is_arguments_shadowed));

	DUK_ASSERT_TOP(thr, entry_top);
	return;

 error_outofregs:
	DUK_ERROR_RANGE(thr, DUK_STR_REG_LIMIT);
	DUK_WO_NORETURN(return;);

 error_argname:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_ARG_NAME);
	DUK_WO_NORETURN(return;);
}

/*
 *  Parse a function-body-like expression (FunctionBody or Program
 *  in E5 grammar) using a two-pass parse.  The productions appear
 *  in the following contexts:
 *
 *    - function expression
 *    - function statement
 *    - function declaration
 *    - getter in object literal
 *    - setter in object literal
 *    - global code
 *    - eval code
 *    - Function constructor body
 *
 *  This function only parses the statement list of the body; the argument
 *  list and possible function name must be initialized by the caller.
 *  For instance, for Function constructor, the argument names are originally
 *  on the value stack.  The parsing of statements ends either at an EOF or
 *  a closing brace; this is controlled by an input flag.
 *
 *  Note that there are many differences affecting parsing and even code
 *  generation:
 *
 *    - Global and eval code have an implicit return value generated
 *      by the last statement; function code does not
 *
 *    - Global code, eval code, and Function constructor body end in
 *      an EOF, other bodies in a closing brace ('}')
 *
 *  Upon entry, 'curr_tok' is ignored and the function will pull in the
 *  first token on its own.  Upon exit, 'curr_tok' is the terminating
 *  token (EOF or closing brace).
 */

DUK_LOCAL void duk__parse_func_body(duk_compiler_ctx *comp_ctx, duk_bool_t expect_eof, duk_bool_t implicit_return_value, duk_bool_t regexp_after, duk_small_int_t expect_token) {
	duk_compiler_func *func;
	duk_hthread *thr;
	duk_regconst_t reg_stmt_value = -1;
	duk_lexer_point lex_pt;
	duk_regconst_t temp_first;
	duk_small_int_t compile_round = 1;

	DUK_ASSERT(comp_ctx != NULL);

	thr = comp_ctx->thr;
	DUK_ASSERT(thr != NULL);

	func = &comp_ctx->curr_func;
	DUK_ASSERT(func != NULL);

	DUK__RECURSION_INCREASE(comp_ctx, thr);

	duk_require_stack(thr, DUK__FUNCTION_BODY_REQUIRE_SLOTS);

	/*
	 *  Store lexer position for a later rewind
	 */

	DUK_LEXER_GETPOINT(&comp_ctx->lex, &lex_pt);

	/*
	 *  Program code (global and eval code) has an implicit return value
	 *  from the last statement value (e.g. eval("1; 2+3;") returns 3).
	 *  This is not the case with functions.  If implicit statement return
	 *  value is requested, all statements are coerced to a register
	 *  allocated here, and used in the implicit return statement below.
	 */

	/* XXX: this is pointless here because pass 1 is throw-away */
	if (implicit_return_value) {
		reg_stmt_value = DUK__ALLOCTEMP(comp_ctx);

		/* If an implicit return value is needed by caller, it must be
		 * initialized to 'undefined' because we don't know whether any
		 * non-empty (where "empty" is a continuation type, and different
		 * from an empty statement) statements will be executed.
		 *
		 * However, since 1st pass is a throwaway one, no need to emit
		 * it here.
		 */
#if 0
		duk__emit_bc(comp_ctx,
		             DUK_OP_LDUNDEF,
		             0);
#endif
	}

	/*
	 *  First pass.
	 *
	 *  Gather variable/function declarations needed for second pass.
	 *  Code generated is dummy and discarded.
	 */

	func->in_directive_prologue = 1;
	func->in_scanning = 1;
	func->may_direct_eval = 0;
	func->id_access_arguments = 0;
	func->id_access_slow = 0;
	func->id_access_slow_own = 0;
	func->reg_stmt_value = reg_stmt_value;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	func->min_line = DUK_INT_MAX;
	func->max_line = 0;
#endif

	/* duk__parse_stmts() expects curr_tok to be set; parse in "allow
	 * regexp literal" mode with current strictness.
	 */
	if (expect_token >= 0) {
		/* Eating a left curly; regexp mode is allowed by left curly
		 * based on duk__token_lbp[] automatically.
		 */
		DUK_ASSERT(expect_token == DUK_TOK_LCURLY);
		duk__update_lineinfo_currtoken(comp_ctx);
		duk__advance_expect(comp_ctx, expect_token);
	} else {
		/* Need to set curr_token.t because lexing regexp mode depends on current
		 * token type.  Zero value causes "allow regexp" mode.
		 */
		comp_ctx->curr_token.t = 0;
		duk__advance(comp_ctx);
	}

	DUK_DDD(DUK_DDDPRINT("begin 1st pass"));
	duk__parse_stmts(comp_ctx,
	                 1,             /* allow source elements */
	                 expect_eof,    /* expect EOF instead of } */
	                 regexp_after); /* regexp after */
	DUK_DDD(DUK_DDDPRINT("end 1st pass"));

	/*
	 *  Second (and possibly third) pass.
	 *
	 *  Generate actual code.  In most cases the need for shuffle
	 *  registers is detected during pass 1, but in some corner cases
	 *  we'll only detect it during pass 2 and a third pass is then
	 *  needed (see GH-115).
	 */

	for (;;) {
		duk_bool_t needs_shuffle_before = comp_ctx->curr_func.needs_shuffle;
		compile_round++;

		/*
		 *  Rewind lexer.
		 *
		 *  duk__parse_stmts() expects curr_tok to be set; parse in "allow regexp
		 *  literal" mode with current strictness.
		 *
		 *  curr_token line number info should be initialized for pass 2 before
		 *  generating prologue, to ensure prologue bytecode gets nice line numbers.
		 */

		DUK_DDD(DUK_DDDPRINT("rewind lexer"));
		DUK_LEXER_SETPOINT(&comp_ctx->lex, &lex_pt);
		comp_ctx->curr_token.t = 0;  /* this is needed for regexp mode */
		comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */
		duk__advance(comp_ctx);

		/*
		 *  Reset function state and perform register allocation, which creates
		 *  'varmap' for second pass.  Function prologue for variable declarations,
		 *  binding value initializations etc is emitted as a by-product.
		 *
		 *  Strict mode restrictions for duplicate and invalid argument
		 *  names are checked here now that we know whether the function
		 *  is actually strict.  See: test-dev-strict-mode-boundary.js.
		 *
		 *  Inner functions are compiled during pass 1 and are not reset.
		 */

		duk__reset_func_for_pass2(comp_ctx);
		func->in_directive_prologue = 1;
		func->in_scanning = 0;

		/* must be able to emit code, alloc consts, etc. */

		duk__init_varmap_and_prologue_for_pass2(comp_ctx,
		                                        (implicit_return_value ? &reg_stmt_value : NULL));
		func->reg_stmt_value = reg_stmt_value;

		temp_first = DUK__GETTEMP(comp_ctx);

		func->temp_first = temp_first;
		func->temp_next = temp_first;
		func->stmt_next = 0;
		func->label_next = 0;

		/* XXX: init or assert catch depth etc -- all values */
		func->id_access_arguments = 0;
		func->id_access_slow = 0;
		func->id_access_slow_own = 0;

		/*
		 *  Check function name validity now that we know strictness.
		 *  This only applies to function declarations and expressions,
		 *  not setter/getter name.
		 *
		 *  See: test-dev-strict-mode-boundary.js
		 */

		if (func->is_function && !func->is_setget && func->h_name != NULL) {
			if (func->is_strict) {
				if (duk__hstring_is_eval_or_arguments(comp_ctx, func->h_name)) {
					DUK_DDD(DUK_DDDPRINT("func name is 'eval' or 'arguments' in strict mode"));
					goto error_funcname;
				}
				if (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(func->h_name)) {
					DUK_DDD(DUK_DDDPRINT("func name is a reserved word in strict mode"));
					goto error_funcname;
				}
			} else {
				if (DUK_HSTRING_HAS_RESERVED_WORD(func->h_name) &&
				    !DUK_HSTRING_HAS_STRICT_RESERVED_WORD(func->h_name)) {
					DUK_DDD(DUK_DDDPRINT("func name is a reserved word in non-strict mode"));
					goto error_funcname;
				}
			}
		}

		/*
		 *  Second pass parsing.
		 */

		if (implicit_return_value) {
			/* Default implicit return value. */
			duk__emit_bc(comp_ctx,
			             DUK_OP_LDUNDEF,
			             0);
		}

		DUK_DDD(DUK_DDDPRINT("begin 2nd pass"));
		duk__parse_stmts(comp_ctx,
		                 1,             /* allow source elements */
		                 expect_eof,    /* expect EOF instead of } */
		                 regexp_after); /* regexp after */
		DUK_DDD(DUK_DDDPRINT("end 2nd pass"));

		duk__update_lineinfo_currtoken(comp_ctx);

		if (needs_shuffle_before == comp_ctx->curr_func.needs_shuffle) {
			/* Shuffle decision not changed. */
			break;
		}
		if (compile_round >= 3) {
			/* Should never happen but avoid infinite loop just in case. */
			DUK_D(DUK_DPRINT("more than 3 compile passes needed, should never happen"));
			DUK_ERROR_INTERNAL(thr);
			DUK_WO_NORETURN(return;);
		}
		DUK_D(DUK_DPRINT("need additional round to compile function, round now %d", (int) compile_round));
	}

	/*
	 *  Emit a final RETURN.
	 *
	 *  It would be nice to avoid emitting an unnecessary "return" opcode
	 *  if the current PC is not reachable.  However, this cannot be reliably
	 *  detected; even if the previous instruction is an unconditional jump,
	 *  there may be a previous jump which jumps to current PC (which is the
	 *  case for iteration and conditional statements, for instance).
	 */

	/* XXX: request a "last statement is terminal" from duk__parse_stmt() and duk__parse_stmts();
	 * we could avoid the last RETURN if we could ensure there is no way to get here
	 * (directly or via a jump)
	 */

	DUK_ASSERT(comp_ctx->curr_func.catch_depth == 0);
	if (reg_stmt_value >= 0) {
		DUK_ASSERT(DUK__ISREG(reg_stmt_value));
		duk__emit_bc(comp_ctx, DUK_OP_RETREG, reg_stmt_value /*reg*/);
	} else {
		duk__emit_op_only(comp_ctx, DUK_OP_RETUNDEF);
	}

	/*
	 *  Peephole optimize JUMP chains.
	 */

	duk__peephole_optimize_bytecode(comp_ctx);

	/*
	 *  comp_ctx->curr_func is now ready to be converted into an actual
	 *  function template.
	 */

	DUK__RECURSION_DECREASE(comp_ctx, thr);
	return;

 error_funcname:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_FUNC_NAME);
	DUK_WO_NORETURN(return;);
}

/*
 *  Parse a function-like expression:
 *
 *    - function expression
 *    - function declaration
 *    - function statement (non-standard)
 *    - setter/getter
 *
 *  Adds the function to comp_ctx->curr_func function table and returns the
 *  function number.
 *
 *  On entry, curr_token points to:
 *
 *    - the token after 'function' for function expression/declaration/statement
 *    - the token after 'set' or 'get' for setter/getter
 */

/* Parse formals. */
DUK_LOCAL void duk__parse_func_formals(duk_compiler_ctx *comp_ctx) {
	duk_hthread *thr = comp_ctx->thr;
	duk_bool_t first = 1;
	duk_uarridx_t n;

	for (;;) {
		if (comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
			break;
		}

		if (first) {
			/* no comma */
			first = 0;
		} else {
			duk__advance_expect(comp_ctx, DUK_TOK_COMMA);
		}

		/* Note: when parsing a formal list in non-strict context, e.g.
		 * "implements" is parsed as an identifier.  When the function is
		 * later detected to be strict, the argument list must be rechecked
		 * against a larger set of reserved words (that of strict mode).
		 * This is handled by duk__parse_func_body().  Here we recognize
		 * whatever tokens are considered reserved in current strictness
		 * (which is not always enough).
		 */

		if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
			DUK_ERROR_SYNTAX(thr, DUK_STR_EXPECTED_IDENTIFIER);
			DUK_WO_NORETURN(return;);
		}
		DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_IDENTIFIER);
		DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
		DUK_DDD(DUK_DDDPRINT("formal argument: %!O",
		                     (duk_heaphdr *) comp_ctx->curr_token.str1));

		/* XXX: append primitive */
		duk_push_hstring(thr, comp_ctx->curr_token.str1);
		n = (duk_uarridx_t) duk_get_length(thr, comp_ctx->curr_func.argnames_idx);
		duk_put_prop_index(thr, comp_ctx->curr_func.argnames_idx, n);

		duk__advance(comp_ctx);  /* eat identifier */
	}
}

/* Parse a function-like expression, assuming that 'comp_ctx->curr_func' is
 * correctly set up.  Assumes that curr_token is just after 'function' (or
 * 'set'/'get' etc).
 */
DUK_LOCAL void duk__parse_func_like_raw(duk_compiler_ctx *comp_ctx, duk_small_uint_t flags) {
	duk_hthread *thr = comp_ctx->thr;
	duk_token *tok;
	duk_bool_t no_advance;

	DUK_ASSERT(comp_ctx->curr_func.num_formals == 0);
	DUK_ASSERT(comp_ctx->curr_func.is_function == 1);
	DUK_ASSERT(comp_ctx->curr_func.is_eval == 0);
	DUK_ASSERT(comp_ctx->curr_func.is_global == 0);
	DUK_ASSERT(comp_ctx->curr_func.is_setget == ((flags & DUK__FUNC_FLAG_GETSET) != 0));

	duk__update_lineinfo_currtoken(comp_ctx);

	/*
	 *  Function name (if any)
	 *
	 *  We don't check for prohibited names here, because we don't
	 *  yet know whether the function will be strict.  Function body
	 *  parsing handles this retroactively.
	 *
	 *  For function expressions and declarations function name must
	 *  be an Identifer (excludes reserved words).  For setter/getter
	 *  it is a PropertyName which allows reserved words and also
	 *  strings and numbers (e.g. "{ get 1() { ... } }").
	 *
	 *  Function parsing may start either from prev_token or curr_token
	 *  (object literal method definition uses prev_token for example).
	 *  This is dealt with for the initial token.
	 */

	no_advance = (flags & DUK__FUNC_FLAG_USE_PREVTOKEN);
	if (no_advance) {
		tok = &comp_ctx->prev_token;
	} else {
		tok = &comp_ctx->curr_token;
	}

	if (flags & DUK__FUNC_FLAG_GETSET) {
		/* PropertyName -> IdentifierName | StringLiteral | NumericLiteral */
		if (tok->t_nores == DUK_TOK_IDENTIFIER || tok->t == DUK_TOK_STRING) {
			duk_push_hstring(thr, tok->str1);       /* keep in valstack */
		} else if (tok->t == DUK_TOK_NUMBER) {
			duk_push_number(thr, tok->num);
			duk_to_string(thr, -1);
		} else {
			DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_GETSET_NAME);
			DUK_WO_NORETURN(return;);
		}
		comp_ctx->curr_func.h_name = duk_known_hstring(thr, -1);  /* borrowed reference */
	} else {
		/* Function name is an Identifier (not IdentifierName), but we get
		 * the raw name (not recognizing keywords) here and perform the name
		 * checks only after pass 1.
		 */
		if (tok->t_nores == DUK_TOK_IDENTIFIER) {
			duk_push_hstring(thr, tok->str1);       /* keep in valstack */
			comp_ctx->curr_func.h_name = duk_known_hstring(thr, -1);  /* borrowed reference */
		} else {
			/* valstack will be unbalanced, which is OK */
			DUK_ASSERT((flags & DUK__FUNC_FLAG_GETSET) == 0);
			DUK_ASSERT(comp_ctx->curr_func.h_name == NULL);
			no_advance = 1;
			if (flags & DUK__FUNC_FLAG_DECL) {
				DUK_ERROR_SYNTAX(thr, DUK_STR_FUNC_NAME_REQUIRED);
				DUK_WO_NORETURN(return;);
			}
		}
	}

	DUK_DD(DUK_DDPRINT("function name: %!O",
	                   (duk_heaphdr *) comp_ctx->curr_func.h_name));

	if (!no_advance) {
		duk__advance(comp_ctx);
	}

	/*
	 *  Formal argument list
	 *
	 *  We don't check for prohibited names or for duplicate argument
	 *  names here, becase we don't yet know whether the function will
	 *  be strict.  Function body parsing handles this retroactively.
	 */

	duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

	duk__parse_func_formals(comp_ctx);

	DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RPAREN);
	duk__advance(comp_ctx);

	/*
	 *  Parse function body
	 */

	duk__parse_func_body(comp_ctx,
	                     0,   /* expect_eof */
	                     0,   /* implicit_return_value */
	                     flags & DUK__FUNC_FLAG_DECL, /* regexp_after */
	                     DUK_TOK_LCURLY);  /* expect_token */

	/*
	 *  Convert duk_compiler_func to a function template and add it
	 *  to the parent function table.
	 */

	duk__convert_to_func_template(comp_ctx);  /* -> [ ... func ] */
}

/* Parse an inner function, adding the function template to the current function's
 * function table.  Return a function number to be used by the outer function.
 *
 * Avoiding O(depth^2) inner function parsing is handled here.  On the first pass,
 * compile and register the function normally into the 'funcs' array, also recording
 * a lexer point (offset/line) to the closing brace of the function.  On the second
 * pass, skip the function and return the same 'fnum' as on the first pass by using
 * a running counter.
 *
 * An unfortunate side effect of this is that when parsing the inner function, almost
 * nothing is known of the outer function, i.e. the inner function's scope.  We don't
 * need that information at the moment, but it would allow some optimizations if it
 * were used.
 */
DUK_LOCAL duk_int_t duk__parse_func_like_fnum(duk_compiler_ctx *comp_ctx, duk_small_uint_t flags) {
	duk_hthread *thr = comp_ctx->thr;
	duk_compiler_func old_func;
	duk_idx_t entry_top;
	duk_int_t fnum;

	/*
	 *  On second pass, skip the function.
	 */

	if (!comp_ctx->curr_func.in_scanning) {
		duk_lexer_point lex_pt;

		fnum = comp_ctx->curr_func.fnum_next++;
		duk_get_prop_index(thr, comp_ctx->curr_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 1));
		lex_pt.offset = (duk_size_t) duk_to_uint(thr, -1);
		duk_pop(thr);
		duk_get_prop_index(thr, comp_ctx->curr_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 2));
		lex_pt.line = duk_to_int(thr, -1);
		duk_pop(thr);

		DUK_DDD(DUK_DDDPRINT("second pass of an inner func, skip the function, reparse closing brace; lex offset=%ld, line=%ld",
		                     (long) lex_pt.offset, (long) lex_pt.line));

		DUK_LEXER_SETPOINT(&comp_ctx->lex, &lex_pt);
		comp_ctx->curr_token.t = 0;  /* this is needed for regexp mode */
		comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */
		duk__advance(comp_ctx);

		/* RegExp is not allowed after a function expression, e.g. in
		 * (function () {} / 123).  A RegExp *is* allowed after a
		 * function declaration!
		 */
		if (flags & DUK__FUNC_FLAG_DECL) {
			comp_ctx->curr_func.allow_regexp_in_adv = 1;
		}
		duk__advance_expect(comp_ctx, DUK_TOK_RCURLY);

		return fnum;
	}

	/*
	 *  On first pass, perform actual parsing.  Remember valstack top on entry
	 *  to restore it later, and switch to using a new function in comp_ctx.
	 */

	entry_top = duk_get_top(thr);
	DUK_DDD(DUK_DDDPRINT("before func: entry_top=%ld, curr_tok.start_offset=%ld",
	                     (long) entry_top, (long) comp_ctx->curr_token.start_offset));

	duk_memcpy(&old_func, &comp_ctx->curr_func, sizeof(duk_compiler_func));

	duk_memzero(&comp_ctx->curr_func, sizeof(duk_compiler_func));
	duk__init_func_valstack_slots(comp_ctx);
	DUK_ASSERT(comp_ctx->curr_func.num_formals == 0);

	/* inherit initial strictness from parent */
	comp_ctx->curr_func.is_strict = old_func.is_strict;

	/* XXX: It might be better to just store the flags into the curr_func
	 * struct and use them as is without this flag interpretation step
	 * here.
	 */
	DUK_ASSERT(comp_ctx->curr_func.is_notail == 0);
	comp_ctx->curr_func.is_function = 1;
	DUK_ASSERT(comp_ctx->curr_func.is_eval == 0);
	DUK_ASSERT(comp_ctx->curr_func.is_global == 0);
	comp_ctx->curr_func.is_setget = ((flags & DUK__FUNC_FLAG_GETSET) != 0);
	comp_ctx->curr_func.is_namebinding = !(flags & (DUK__FUNC_FLAG_GETSET |
	                                                DUK__FUNC_FLAG_METDEF |
	                                                DUK__FUNC_FLAG_DECL));  /* no name binding for: declarations, objlit getset, objlit method def */
	comp_ctx->curr_func.is_constructable = !(flags & (DUK__FUNC_FLAG_GETSET |
	                                                  DUK__FUNC_FLAG_METDEF));  /* not constructable: objlit getset, objlit method def */

	/*
	 *  Parse inner function
	 */

	duk__parse_func_like_raw(comp_ctx, flags);  /* pushes function template */

	/* prev_token.start_offset points to the closing brace here; when skipping
	 * we're going to reparse the closing brace to ensure semicolon insertion
	 * etc work as expected.
	 */
	DUK_DDD(DUK_DDDPRINT("after func: prev_tok.start_offset=%ld, curr_tok.start_offset=%ld",
	                     (long) comp_ctx->prev_token.start_offset, (long) comp_ctx->curr_token.start_offset));
	DUK_ASSERT(comp_ctx->lex.input[comp_ctx->prev_token.start_offset] == (duk_uint8_t) DUK_ASC_RCURLY);

	/* XXX: append primitive */
	DUK_ASSERT(duk_get_length(thr, old_func.funcs_idx) == (duk_size_t) (old_func.fnum_next * 3));
	fnum = old_func.fnum_next++;

	if (fnum > DUK__MAX_FUNCS) {
		DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_FUNC_LIMIT);
		DUK_WO_NORETURN(return 0;);
	}

	/* array writes autoincrement length */
	(void) duk_put_prop_index(thr, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3));
	duk_push_size_t(thr, comp_ctx->prev_token.start_offset);
	(void) duk_put_prop_index(thr, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 1));
	duk_push_int(thr, comp_ctx->prev_token.start_line);
	(void) duk_put_prop_index(thr, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 2));

	/*
	 *  Cleanup: restore original function, restore valstack state.
	 *
	 *  Function declaration handling needs the function name to be pushed
	 *  on the value stack.
	 */

	if (flags & DUK__FUNC_FLAG_PUSHNAME_PASS1) {
		DUK_ASSERT(comp_ctx->curr_func.h_name != NULL);
		duk_push_hstring(thr, comp_ctx->curr_func.h_name);
		duk_replace(thr, entry_top);
		duk_set_top(thr, entry_top + 1);
	} else {
		duk_set_top(thr, entry_top);
	}
	duk_memcpy((void *) &comp_ctx->curr_func, (void *) &old_func, sizeof(duk_compiler_func));

	return fnum;
}

/*
 *  Compile input string into an executable function template without
 *  arguments.
 *
 *  The string is parsed as the "Program" production of ECMAScript E5.
 *  Compilation context can be either global code or eval code (see E5
 *  Sections 14 and 15.1.2.1).
 *
 *  Input stack:  [ ... filename ]
 *  Output stack: [ ... func_template ]
 */

/* XXX: source code property */

DUK_LOCAL duk_ret_t duk__js_compile_raw(duk_hthread *thr, void *udata) {
	duk_hstring *h_filename;
	duk__compiler_stkstate *comp_stk;
	duk_compiler_ctx *comp_ctx;
	duk_lexer_point *lex_pt;
	duk_compiler_func *func;
	duk_idx_t entry_top;
	duk_bool_t is_strict;
	duk_bool_t is_eval;
	duk_bool_t is_funcexpr;
	duk_small_uint_t flags;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(udata != NULL);

	/*
	 *  Arguments check
	 */

	entry_top = duk_get_top(thr);
	DUK_ASSERT(entry_top >= 1);

	comp_stk = (duk__compiler_stkstate *) udata;
	comp_ctx = &comp_stk->comp_ctx_alloc;
	lex_pt = &comp_stk->lex_pt_alloc;
	DUK_ASSERT(comp_ctx != NULL);
	DUK_ASSERT(lex_pt != NULL);

	flags = comp_stk->flags;
	is_eval = (flags & DUK_COMPILE_EVAL ? 1 : 0);
	is_strict = (flags & DUK_COMPILE_STRICT ? 1 : 0);
	is_funcexpr = (flags & DUK_COMPILE_FUNCEXPR ? 1 : 0);

	h_filename = duk_get_hstring(thr, -1);  /* may be undefined */

	/*
	 *  Init compiler and lexer contexts
	 */

	func = &comp_ctx->curr_func;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	comp_ctx->thr = NULL;
	comp_ctx->h_filename = NULL;
	comp_ctx->prev_token.str1 = NULL;
	comp_ctx->prev_token.str2 = NULL;
	comp_ctx->curr_token.str1 = NULL;
	comp_ctx->curr_token.str2 = NULL;
#endif

	duk_require_stack(thr, DUK__COMPILE_ENTRY_SLOTS);

	duk_push_dynamic_buffer(thr, 0);       /* entry_top + 0 */
	duk_push_undefined(thr);               /* entry_top + 1 */
	duk_push_undefined(thr);               /* entry_top + 2 */
	duk_push_undefined(thr);               /* entry_top + 3 */
	duk_push_undefined(thr);               /* entry_top + 4 */

	comp_ctx->thr = thr;
	comp_ctx->h_filename = h_filename;
	comp_ctx->tok11_idx = entry_top + 1;
	comp_ctx->tok12_idx = entry_top + 2;
	comp_ctx->tok21_idx = entry_top + 3;
	comp_ctx->tok22_idx = entry_top + 4;
	comp_ctx->recursion_limit = DUK_USE_COMPILER_RECLIMIT;

	/* comp_ctx->lex has been pre-initialized by caller: it has been
	 * zeroed and input/input_length has been set.
	 */
	comp_ctx->lex.thr = thr;
	/* comp_ctx->lex.input and comp_ctx->lex.input_length filled by caller */
	comp_ctx->lex.slot1_idx = comp_ctx->tok11_idx;
	comp_ctx->lex.slot2_idx = comp_ctx->tok12_idx;
	comp_ctx->lex.buf_idx = entry_top + 0;
	comp_ctx->lex.buf = (duk_hbuffer_dynamic *) duk_known_hbuffer(thr, entry_top + 0);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(comp_ctx->lex.buf) && !DUK_HBUFFER_HAS_EXTERNAL(comp_ctx->lex.buf));
	comp_ctx->lex.token_limit = DUK_COMPILER_TOKEN_LIMIT;

	lex_pt->offset = 0;
	lex_pt->line = 1;
	DUK_LEXER_SETPOINT(&comp_ctx->lex, lex_pt);    /* fills window */
	comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */

	/*
	 *  Initialize function state for a zero-argument function
	 */

	duk__init_func_valstack_slots(comp_ctx);
	DUK_ASSERT(func->num_formals == 0);

	if (is_funcexpr) {
		/* Name will be filled from function expression, not by caller.
		 * This case is used by Function constructor and duk_compile()
		 * API with the DUK_COMPILE_FUNCTION option.
		 */
		DUK_ASSERT(func->h_name == NULL);
	} else {
		duk_push_hstring_stridx(thr, (is_eval ? DUK_STRIDX_EVAL :
		                                        DUK_STRIDX_GLOBAL));
		func->h_name = duk_get_hstring(thr, -1);
	}

	/*
	 *  Parse a function body or a function-like expression, depending
	 *  on flags.
	 */

	DUK_ASSERT(func->is_setget == 0);
	func->is_strict = (duk_uint8_t) is_strict;
	DUK_ASSERT(func->is_notail == 0);

	if (is_funcexpr) {
		func->is_function = 1;
		DUK_ASSERT(func->is_eval == 0);
		DUK_ASSERT(func->is_global == 0);
		func->is_namebinding = 1;
		func->is_constructable = 1;

		duk__advance(comp_ctx);  /* init 'curr_token' */
		duk__advance_expect(comp_ctx, DUK_TOK_FUNCTION);
		(void) duk__parse_func_like_raw(comp_ctx, 0 /*flags*/);
	} else {
		DUK_ASSERT(func->is_function == 0);
		DUK_ASSERT(is_eval == 0 || is_eval == 1);
		func->is_eval = (duk_uint8_t) is_eval;
		func->is_global = (duk_uint8_t) !is_eval;
		DUK_ASSERT(func->is_namebinding == 0);
		DUK_ASSERT(func->is_constructable == 0);

		duk__parse_func_body(comp_ctx,
		                     1,             /* expect_eof */
		                     1,             /* implicit_return_value */
		                     1,             /* regexp_after (does not matter) */
		                     -1);           /* expect_token */
	}

	/*
	 *  Convert duk_compiler_func to a function template
	 */

	duk__convert_to_func_template(comp_ctx);

	/*
	 *  Wrapping duk_safe_call() will mangle the stack, just return stack top
	 */

	/* [ ... filename (temps) func ] */

	return 1;
}

DUK_INTERNAL void duk_js_compile(duk_hthread *thr, const duk_uint8_t *src_buffer, duk_size_t src_length, duk_small_uint_t flags) {
	duk__compiler_stkstate comp_stk;
	duk_compiler_ctx *prev_ctx;
	duk_ret_t safe_rc;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(src_buffer != NULL);

	/* preinitialize lexer state partially */
	duk_memzero(&comp_stk, sizeof(comp_stk));
	comp_stk.flags = flags;
	DUK_LEXER_INITCTX(&comp_stk.comp_ctx_alloc.lex);
	comp_stk.comp_ctx_alloc.lex.input = src_buffer;
	comp_stk.comp_ctx_alloc.lex.input_length = src_length;
	comp_stk.comp_ctx_alloc.lex.flags = flags;  /* Forward flags directly for now. */

	/* [ ... filename ] */

	prev_ctx = thr->compile_ctx;
	thr->compile_ctx = &comp_stk.comp_ctx_alloc;  /* for duk_error_augment.c */
	safe_rc = duk_safe_call(thr, duk__js_compile_raw, (void *) &comp_stk /*udata*/, 1 /*nargs*/, 1 /*nrets*/);
	thr->compile_ctx = prev_ctx;  /* must restore reliably before returning */

	if (safe_rc != DUK_EXEC_SUCCESS) {
		DUK_D(DUK_DPRINT("compilation failed: %!T", duk_get_tval(thr, -1)));
		(void) duk_throw(thr);
		DUK_WO_NORETURN(return;);
	}

	/* [ ... template ] */
}

/* automatic undefs */
#undef DUK__ALLOCTEMP
#undef DUK__ALLOCTEMPS
#undef DUK__ALLOW_AUTO_SEMI_ALWAYS
#undef DUK__BC_INITIAL_INSTS
#undef DUK__BP_ADDITIVE
#undef DUK__BP_ASSIGNMENT
#undef DUK__BP_BAND
#undef DUK__BP_BOR
#undef DUK__BP_BXOR
#undef DUK__BP_CALL
#undef DUK__BP_CLOSING
#undef DUK__BP_COMMA
#undef DUK__BP_CONDITIONAL
#undef DUK__BP_EOF
#undef DUK__BP_EQUALITY
#undef DUK__BP_EXPONENTIATION
#undef DUK__BP_FOR_EXPR
#undef DUK__BP_INVALID
#undef DUK__BP_LAND
#undef DUK__BP_LOR
#undef DUK__BP_MEMBER
#undef DUK__BP_MULTIPLICATIVE
#undef DUK__BP_POSTFIX
#undef DUK__BP_RELATIONAL
#undef DUK__BP_SHIFT
#undef DUK__COMPILE_ENTRY_SLOTS
#undef DUK__CONST_MARKER
#undef DUK__DUMP_ISPEC
#undef DUK__DUMP_IVALUE
#undef DUK__EMIT_FLAG_A_IS_SOURCE
#undef DUK__EMIT_FLAG_BC_REGCONST
#undef DUK__EMIT_FLAG_B_IS_TARGET
#undef DUK__EMIT_FLAG_C_IS_TARGET
#undef DUK__EMIT_FLAG_NO_SHUFFLE_A
#undef DUK__EMIT_FLAG_NO_SHUFFLE_B
#undef DUK__EMIT_FLAG_NO_SHUFFLE_C
#undef DUK__EMIT_FLAG_RESERVE_JUMPSLOT
#undef DUK__EXPR_FLAG_ALLOW_EMPTY
#undef DUK__EXPR_FLAG_REJECT_IN
#undef DUK__EXPR_FLAG_REQUIRE_INIT
#undef DUK__EXPR_RBP_MASK
#undef DUK__FUNCTION_BODY_REQUIRE_SLOTS
#undef DUK__FUNCTION_INIT_REQUIRE_SLOTS
#undef DUK__FUNC_FLAG_DECL
#undef DUK__FUNC_FLAG_GETSET
#undef DUK__FUNC_FLAG_METDEF
#undef DUK__FUNC_FLAG_PUSHNAME_PASS1
#undef DUK__FUNC_FLAG_USE_PREVTOKEN
#undef DUK__GETCONST_MAX_CONSTS_CHECK
#undef DUK__GETTEMP
#undef DUK__HAS_TERM
#undef DUK__HAS_VAL
#undef DUK__ISCONST
#undef DUK__ISREG
#undef DUK__ISREG_NOTTEMP
#undef DUK__ISREG_TEMP
#undef DUK__IS_TERMINAL
#undef DUK__IVAL_FLAG_ALLOW_CONST
#undef DUK__IVAL_FLAG_REQUIRE_SHORT
#undef DUK__IVAL_FLAG_REQUIRE_TEMP
#undef DUK__MAX_ARRAY_INIT_VALUES
#undef DUK__MAX_CONSTS
#undef DUK__MAX_FUNCS
#undef DUK__MAX_OBJECT_INIT_PAIRS
#undef DUK__MAX_TEMPS
#undef DUK__MK_LBP
#undef DUK__MK_LBP_FLAGS
#undef DUK__OBJ_LIT_KEY_GET
#undef DUK__OBJ_LIT_KEY_PLAIN
#undef DUK__OBJ_LIT_KEY_SET
#undef DUK__PARSE_EXPR_SLOTS
#undef DUK__PARSE_STATEMENTS_SLOTS
#undef DUK__RECURSION_DECREASE
#undef DUK__RECURSION_INCREASE
#undef DUK__REMOVECONST
#undef DUK__SETTEMP
#undef DUK__SETTEMP_CHECKMAX
#undef DUK__STILL_PROLOGUE
#undef DUK__TOKEN_LBP_BP_MASK
#undef DUK__TOKEN_LBP_FLAG_NO_REGEXP
#undef DUK__TOKEN_LBP_FLAG_TERMINATES
#undef DUK__TOKEN_LBP_FLAG_UNUSED
#undef DUK__TOKEN_LBP_GET_BP
/*
 *  ECMAScript bytecode executor.
 */

/* #include duk_internal.h -> already included */

/*
 *  Local declarations.
 */

DUK_LOCAL_DECL void duk__js_execute_bytecode_inner(duk_hthread *entry_thread, duk_activation *entry_act);

/*
 *  Misc helpers.
 */

/* Replace value stack top to value at 'tv_ptr'.  Optimize for
 * performance by only applying the net refcount change.
 */
#define DUK__REPLACE_TO_TVPTR(thr,tv_ptr) do { \
		duk_hthread *duk__thr; \
		duk_tval *duk__tvsrc; \
		duk_tval *duk__tvdst; \
		duk_tval duk__tvtmp; \
		duk__thr = (thr); \
		duk__tvsrc = DUK_GET_TVAL_NEGIDX(duk__thr, -1); \
		duk__tvdst = (tv_ptr); \
		DUK_TVAL_SET_TVAL(&duk__tvtmp, duk__tvdst); \
		DUK_TVAL_SET_TVAL(duk__tvdst, duk__tvsrc); \
		DUK_TVAL_SET_UNDEFINED(duk__tvsrc);  /* value stack init policy */ \
		duk__thr->valstack_top = duk__tvsrc; \
		DUK_TVAL_DECREF(duk__thr, &duk__tvtmp); \
	} while (0)

/* XXX: candidate of being an internal shared API call */
#if 0  /* unused */
DUK_LOCAL void duk__push_tvals_incref_only(duk_hthread *thr, duk_tval *tv_src, duk_small_uint_fast_t count) {
	duk_tval *tv_dst;
	duk_size_t copy_size;
	duk_size_t i;

	tv_dst = thr->valstack_top;
	copy_size = sizeof(duk_tval) * count;
	duk_memcpy((void *) tv_dst, (const void *) tv_src, copy_size);
	for (i = 0; i < count; i++) {
		DUK_TVAL_INCREF(thr, tv_dst);
		tv_dst++;
	}
	thr->valstack_top = tv_dst;
}
#endif

/*
 *  Arithmetic, binary, and logical helpers.
 *
 *  Note: there is no opcode for logical AND or logical OR; this is on
 *  purpose, because the evalution order semantics for them make such
 *  opcodes pretty pointless: short circuiting means they are most
 *  comfortably implemented as jumps.  However, a logical NOT opcode
 *  is useful.
 *
 *  Note: careful with duk_tval pointers here: they are potentially
 *  invalidated by any DECREF and almost any API call.  It's still
 *  preferable to work without making a copy but that's not always
 *  possible.
 */

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF duk_double_t duk__compute_mod(duk_double_t d1, duk_double_t d2) {
	return (duk_double_t) duk_js_arith_mod((double) d1, (double) d2);
}

#if defined(DUK_USE_ES7_EXP_OPERATOR)
DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF duk_double_t duk__compute_exp(duk_double_t d1, duk_double_t d2) {
	return (duk_double_t) duk_js_arith_pow((double) d1, (double) d2);
}
#endif

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_arith_add(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_fast_t idx_z) {
	/*
	 *  Addition operator is different from other arithmetic
	 *  operations in that it also provides string concatenation.
	 *  Hence it is implemented separately.
	 *
	 *  There is a fast path for number addition.  Other cases go
	 *  through potentially multiple coercions as described in the
	 *  E5 specification.  It may be possible to reduce the number
	 *  of coercions, but this must be done carefully to preserve
	 *  the exact semantics.
	 *
	 *  E5 Section 11.6.1.
	 *
	 *  Custom types also have special behavior implemented here.
	 */

	duk_double_union du;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_x != NULL);  /* may be reg or const */
	DUK_ASSERT(tv_y != NULL);  /* may be reg or const */
	DUK_ASSERT_DISABLE(idx_z >= 0);  /* unsigned */
	DUK_ASSERT((duk_uint_t) idx_z < (duk_uint_t) duk_get_top(thr));

	/*
	 *  Fast paths
	 */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
		duk_int64_t v1, v2, v3;
		duk_int32_t v3_hi;
		duk_tval *tv_z;

		/* Input values are signed 48-bit so we can detect overflow
		 * reliably from high bits or just a comparison.
		 */

		v1 = DUK_TVAL_GET_FASTINT(tv_x);
		v2 = DUK_TVAL_GET_FASTINT(tv_y);
		v3 = v1 + v2;
		v3_hi = (duk_int32_t) (v3 >> 32);
		if (DUK_LIKELY(v3_hi >= DUK_I64_CONSTANT(-0x8000) && v3_hi <= DUK_I64_CONSTANT(0x7fff))) {
			tv_z = thr->valstack_bottom + idx_z;
			DUK_TVAL_SET_FASTINT_UPDREF(thr, tv_z, v3);  /* side effects */
			return;
		} else {
			/* overflow, fall through */
			;
		}
	}
#endif  /* DUK_USE_FASTINT */

	if (DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y)) {
#if !defined(DUK_USE_EXEC_PREFER_SIZE)
		duk_tval *tv_z;
#endif

		du.d = DUK_TVAL_GET_NUMBER(tv_x) + DUK_TVAL_GET_NUMBER(tv_y);
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		duk_push_number(thr, du.d);  /* will NaN normalize result */
		duk_replace(thr, (duk_idx_t) idx_z);
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
		tv_z = thr->valstack_bottom + idx_z;
		DUK_TVAL_SET_NUMBER_UPDREF(thr, tv_z, du.d);  /* side effects */
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
		return;
	}

	/*
	 *  Slow path: potentially requires function calls for coercion
	 */

	duk_push_tval(thr, tv_x);
	duk_push_tval(thr, tv_y);
	duk_to_primitive(thr, -2, DUK_HINT_NONE);  /* side effects -> don't use tv_x, tv_y after */
	duk_to_primitive(thr, -1, DUK_HINT_NONE);

	/* Since Duktape 2.x plain buffers are treated like ArrayBuffer. */
	if (duk_is_string(thr, -2) || duk_is_string(thr, -1)) {
		/* Symbols shouldn't technically be handled here, but should
		 * go into the default ToNumber() coercion path instead and
		 * fail there with a TypeError.  However, there's a ToString()
		 * in duk_concat_2() which also fails with TypeError so no
		 * explicit check is needed.
		 */
		duk_concat_2(thr);  /* [... s1 s2] -> [... s1+s2] */
	} else {
		duk_double_t d1, d2;

		d1 = duk_to_number_m2(thr);
		d2 = duk_to_number_m1(thr);
		DUK_ASSERT(duk_is_number(thr, -2));
		DUK_ASSERT(duk_is_number(thr, -1));
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(d1);
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(d2);

		du.d = d1 + d2;
		duk_pop_2_unsafe(thr);
		duk_push_number(thr, du.d);  /* will NaN normalize result */
	}
	duk_replace(thr, (duk_idx_t) idx_z);  /* side effects */
}

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_arith_binary_op(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_uint_fast_t idx_z, duk_small_uint_fast_t opcode) {
	/*
	 *  Arithmetic operations other than '+' have number-only semantics
	 *  and are implemented here.  The separate switch-case here means a
	 *  "double dispatch" of the arithmetic opcode, but saves code space.
	 *
	 *  E5 Sections 11.5, 11.5.1, 11.5.2, 11.5.3, 11.6, 11.6.1, 11.6.2, 11.6.3.
	 */

	duk_double_t d1, d2;
	duk_double_union du;
	duk_small_uint_fast_t opcode_shifted;
#if defined(DUK_USE_FASTINT) || !defined(DUK_USE_EXEC_PREFER_SIZE)
	duk_tval *tv_z;
#endif

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_x != NULL);  /* may be reg or const */
	DUK_ASSERT(tv_y != NULL);  /* may be reg or const */
	DUK_ASSERT_DISABLE(idx_z >= 0);  /* unsigned */
	DUK_ASSERT((duk_uint_t) idx_z < (duk_uint_t) duk_get_top(thr));

	opcode_shifted = opcode >> 2;  /* Get base opcode without reg/const modifiers. */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
		duk_int64_t v1, v2, v3;
		duk_int32_t v3_hi;

		v1 = DUK_TVAL_GET_FASTINT(tv_x);
		v2 = DUK_TVAL_GET_FASTINT(tv_y);

		switch (opcode_shifted) {
		case DUK_OP_SUB >> 2: {
			v3 = v1 - v2;
			break;
		}
		case DUK_OP_MUL >> 2: {
			/* Must ensure result is 64-bit (no overflow); a
			 * simple and sufficient fast path is to allow only
			 * 32-bit inputs.  Avoid zero inputs to avoid
			 * negative zero issues (-1 * 0 = -0, for instance).
			 */
			if (v1 >= DUK_I64_CONSTANT(-0x80000000) && v1 <= DUK_I64_CONSTANT(0x7fffffff) && v1 != 0 &&
			    v2 >= DUK_I64_CONSTANT(-0x80000000) && v2 <= DUK_I64_CONSTANT(0x7fffffff) && v2 != 0) {
				v3 = v1 * v2;
			} else {
				goto skip_fastint;
			}
			break;
		}
		case DUK_OP_DIV >> 2: {
			/* Don't allow a zero divisor.  Fast path check by
			 * "verifying" with multiplication.  Also avoid zero
			 * dividend to avoid negative zero issues (0 / -1 = -0
			 * for instance).
			 */
			if (v1 == 0 || v2 == 0) {
				goto skip_fastint;
			}
			v3 = v1 / v2;
			if (v3 * v2 != v1) {
				goto skip_fastint;
			}
			break;
		}
		case DUK_OP_MOD >> 2: {
			/* Don't allow a zero divisor.  Restrict both v1 and
			 * v2 to positive values to avoid compiler specific
			 * behavior.
			 */
			if (v1 < 1 || v2 < 1) {
				goto skip_fastint;
			}
			v3 = v1 % v2;
			DUK_ASSERT(v3 >= 0);
			DUK_ASSERT(v3 < v2);
			DUK_ASSERT(v1 - (v1 / v2) * v2 == v3);
			break;
		}
		default: {
			/* Possible with DUK_OP_EXP. */
			goto skip_fastint;
		}
		}

		v3_hi = (duk_int32_t) (v3 >> 32);
		if (DUK_LIKELY(v3_hi >= DUK_I64_CONSTANT(-0x8000) && v3_hi <= DUK_I64_CONSTANT(0x7fff))) {
			tv_z = thr->valstack_bottom + idx_z;
			DUK_TVAL_SET_FASTINT_UPDREF(thr, tv_z, v3);  /* side effects */
			return;
		}
		/* fall through if overflow etc */
	}
 skip_fastint:
#endif  /* DUK_USE_FASTINT */

	if (DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y)) {
		/* fast path */
		d1 = DUK_TVAL_GET_NUMBER(tv_x);
		d2 = DUK_TVAL_GET_NUMBER(tv_y);
	} else {
		duk_push_tval(thr, tv_x);
		duk_push_tval(thr, tv_y);
		d1 = duk_to_number_m2(thr);  /* side effects */
		d2 = duk_to_number_m1(thr);
		DUK_ASSERT(duk_is_number(thr, -2));
		DUK_ASSERT(duk_is_number(thr, -1));
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(d1);
		DUK_ASSERT_DOUBLE_IS_NORMALIZED(d2);
		duk_pop_2_unsafe(thr);
	}

	switch (opcode_shifted) {
	case DUK_OP_SUB >> 2: {
		du.d = d1 - d2;
		break;
	}
	case DUK_OP_MUL >> 2: {
		du.d = d1 * d2;
		break;
	}
	case DUK_OP_DIV >> 2: {
		/* Division-by-zero is undefined behavior, so
		 * rely on a helper.
		 */
		du.d = duk_double_div(d1, d2);
		break;
	}
	case DUK_OP_MOD >> 2: {
		du.d = duk__compute_mod(d1, d2);
		break;
	}
#if defined(DUK_USE_ES7_EXP_OPERATOR)
	case DUK_OP_EXP >> 2: {
		du.d = duk__compute_exp(d1, d2);
		break;
	}
#endif
	default: {
		DUK_UNREACHABLE();
		du.d = DUK_DOUBLE_NAN;  /* should not happen */
		break;
	}
	}

#if defined(DUK_USE_EXEC_PREFER_SIZE)
	duk_push_number(thr, du.d);  /* will NaN normalize result */
	duk_replace(thr, (duk_idx_t) idx_z);
#else  /* DUK_USE_EXEC_PREFER_SIZE */
	/* important to use normalized NaN with 8-byte tagged types */
	DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
	DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
	tv_z = thr->valstack_bottom + idx_z;
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv_z, du.d);  /* side effects */
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
}

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_bitwise_binary_op(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_fast_t idx_z, duk_small_uint_fast_t opcode) {
	/*
	 *  Binary bitwise operations use different coercions (ToInt32, ToUint32)
	 *  depending on the operation.  We coerce the arguments first using
	 *  ToInt32(), and then cast to an 32-bit value if necessary.  Note that
	 *  such casts must be correct even if there is no native 32-bit type
	 *  (e.g., duk_int32_t and duk_uint32_t are 64-bit).
	 *
	 *  E5 Sections 11.10, 11.7.1, 11.7.2, 11.7.3
	 */

	duk_int32_t i1, i2, i3;
	duk_uint32_t u1, u2, u3;
#if defined(DUK_USE_FASTINT)
	duk_int64_t fi3;
#else
	duk_double_t d3;
#endif
	duk_small_uint_fast_t opcode_shifted;
#if defined(DUK_USE_FASTINT) || !defined(DUK_USE_EXEC_PREFER_SIZE)
	duk_tval *tv_z;
#endif

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_x != NULL);  /* may be reg or const */
	DUK_ASSERT(tv_y != NULL);  /* may be reg or const */
	DUK_ASSERT_DISABLE(idx_z >= 0);  /* unsigned */
	DUK_ASSERT((duk_uint_t) idx_z < (duk_uint_t) duk_get_top(thr));

	opcode_shifted = opcode >> 2;  /* Get base opcode without reg/const modifiers. */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
		i1 = (duk_int32_t) DUK_TVAL_GET_FASTINT_I32(tv_x);
		i2 = (duk_int32_t) DUK_TVAL_GET_FASTINT_I32(tv_y);
	}
	else
#endif  /* DUK_USE_FASTINT */
	{
		duk_push_tval(thr, tv_x);
		duk_push_tval(thr, tv_y);
		i1 = duk_to_int32(thr, -2);
		i2 = duk_to_int32(thr, -1);
		duk_pop_2_unsafe(thr);
	}

	switch (opcode_shifted) {
	case DUK_OP_BAND >> 2: {
		i3 = i1 & i2;
		break;
	}
	case DUK_OP_BOR >> 2: {
		i3 = i1 | i2;
		break;
	}
	case DUK_OP_BXOR >> 2: {
		i3 = i1 ^ i2;
		break;
	}
	case DUK_OP_BASL >> 2: {
		/* Signed shift, named "arithmetic" (asl) because the result
		 * is signed, e.g. 4294967295 << 1 -> -2.  Note that result
		 * must be masked.
		 */

		u2 = ((duk_uint32_t) i2) & 0xffffffffUL;
		i3 = (duk_int32_t) (((duk_uint32_t) i1) << (u2 & 0x1fUL));  /* E5 Section 11.7.1, steps 7 and 8 */
		i3 = i3 & ((duk_int32_t) 0xffffffffUL);                     /* Note: left shift, should mask */
		break;
	}
	case DUK_OP_BASR >> 2: {
		/* signed shift */

		u2 = ((duk_uint32_t) i2) & 0xffffffffUL;
		i3 = i1 >> (u2 & 0x1fUL);                      /* E5 Section 11.7.2, steps 7 and 8 */
		break;
	}
	case DUK_OP_BLSR >> 2: {
		/* unsigned shift */

		u1 = ((duk_uint32_t) i1) & 0xffffffffUL;
		u2 = ((duk_uint32_t) i2) & 0xffffffffUL;

		/* special result value handling */
		u3 = u1 >> (u2 & 0x1fUL);     /* E5 Section 11.7.2, steps 7 and 8 */
#if defined(DUK_USE_FASTINT)
		fi3 = (duk_int64_t) u3;
		goto fastint_result_set;
#else
		d3 = (duk_double_t) u3;
		goto result_set;
#endif
	}
	default: {
		DUK_UNREACHABLE();
		i3 = 0;  /* should not happen */
		break;
	}
	}

#if defined(DUK_USE_FASTINT)
	/* Result is always fastint compatible. */
	/* XXX: Set 32-bit result (but must then handle signed and
	 * unsigned results separately).
	 */
	fi3 = (duk_int64_t) i3;

 fastint_result_set:
	tv_z = thr->valstack_bottom + idx_z;
	DUK_TVAL_SET_FASTINT_UPDREF(thr, tv_z, fi3);  /* side effects */
#else  /* DUK_USE_FASTINT */
	d3 = (duk_double_t) i3;

 result_set:
	DUK_ASSERT(!DUK_ISNAN(d3));            /* 'd3' is never NaN, so no need to normalize */
	DUK_ASSERT_DOUBLE_IS_NORMALIZED(d3);   /* always normalized */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
	duk_push_number(thr, d3);  /* would NaN normalize result, but unnecessary */
	duk_replace(thr, (duk_idx_t) idx_z);
#else  /* DUK_USE_EXEC_PREFER_SIZE */
	tv_z = thr->valstack_bottom + idx_z;
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv_z, d3);  /* side effects */
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
#endif  /* DUK_USE_FASTINT */
}

/* In-place unary operation. */
DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_arith_unary_op(duk_hthread *thr, duk_uint_fast_t idx_src, duk_uint_fast_t idx_dst, duk_small_uint_fast_t opcode) {
	/*
	 *  Arithmetic operations other than '+' have number-only semantics
	 *  and are implemented here.  The separate switch-case here means a
	 *  "double dispatch" of the arithmetic opcode, but saves code space.
	 *
	 *  E5 Sections 11.5, 11.5.1, 11.5.2, 11.5.3, 11.6, 11.6.1, 11.6.2, 11.6.3.
	 */

	duk_tval *tv;
	duk_double_t d1;
	duk_double_union du;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(opcode == DUK_OP_UNM || opcode == DUK_OP_UNP);
	DUK_ASSERT_DISABLE(idx_src >= 0);
	DUK_ASSERT_DISABLE(idx_dst >= 0);

	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_src);

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		duk_int64_t v1, v2;

		v1 = DUK_TVAL_GET_FASTINT(tv);
		if (opcode == DUK_OP_UNM) {
			/* The smallest fastint is no longer 48-bit when
			 * negated.  Positive zero becames negative zero
			 * (cannot be represented) when negated.
			 */
			if (DUK_LIKELY(v1 != DUK_FASTINT_MIN && v1 != 0)) {
				v2 = -v1;
				tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
				DUK_TVAL_SET_FASTINT_UPDREF(thr, tv, v2);
				return;
			}
		} else {
			/* ToNumber() for a fastint is a no-op. */
			DUK_ASSERT(opcode == DUK_OP_UNP);
			v2 = v1;
			tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
			DUK_TVAL_SET_FASTINT_UPDREF(thr, tv, v2);
			return;
		}
		/* fall through if overflow etc */
	}
#endif  /* DUK_USE_FASTINT */

	if (DUK_TVAL_IS_NUMBER(tv)) {
		d1 = DUK_TVAL_GET_NUMBER(tv);
	} else {
		d1 = duk_to_number_tval(thr, tv);  /* side effects */
	}

	if (opcode == DUK_OP_UNP) {
		/* ToNumber() for a double is a no-op, but unary plus is
		 * used to force a fastint check so do that here.
		 */
		du.d = d1;
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
#if defined(DUK_USE_FASTINT)
		tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
		DUK_TVAL_SET_NUMBER_CHKFAST_UPDREF(thr, tv, du.d);  /* always 'fast', i.e. inlined */
		return;
#endif
	} else {
		DUK_ASSERT(opcode == DUK_OP_UNM);
		du.d = -d1;
		DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);  /* mandatory if du.d is a NaN */
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
	}

	/* XXX: size optimize: push+replace? */
	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv, du.d);
}

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_bitwise_not(duk_hthread *thr, duk_uint_fast_t idx_src, duk_uint_fast_t idx_dst) {
	/*
	 *  E5 Section 11.4.8
	 */

	duk_tval *tv;
	duk_int32_t i1, i2;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT_DISABLE(idx_src >= 0);
	DUK_ASSERT_DISABLE(idx_dst >= 0);
	DUK_ASSERT((duk_uint_t) idx_src < (duk_uint_t) duk_get_top(thr));
	DUK_ASSERT((duk_uint_t) idx_dst < (duk_uint_t) duk_get_top(thr));

	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_src);

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		i1 = (duk_int32_t) DUK_TVAL_GET_FASTINT_I32(tv);
	}
	else
#endif  /* DUK_USE_FASTINT */
	{
		duk_push_tval(thr, tv);
		i1 = duk_to_int32(thr, -1);  /* side effects */
		duk_pop_unsafe(thr);
	}

	/* Result is always fastint compatible. */
	i2 = ~i1;
	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
	DUK_TVAL_SET_I32_UPDREF(thr, tv, i2);  /* side effects */
}

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__vm_logical_not(duk_hthread *thr, duk_uint_fast_t idx_src, duk_uint_fast_t idx_dst) {
	/*
	 *  E5 Section 11.4.9
	 */

	duk_tval *tv;
	duk_bool_t res;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT_DISABLE(idx_src >= 0);
	DUK_ASSERT_DISABLE(idx_dst >= 0);
	DUK_ASSERT((duk_uint_t) idx_src < (duk_uint_t) duk_get_top(thr));
	DUK_ASSERT((duk_uint_t) idx_dst < (duk_uint_t) duk_get_top(thr));

	/* ToBoolean() does not require any operations with side effects so
	 * we can do it efficiently.  For footprint it would be better to use
	 * duk_js_toboolean() and then push+replace to the result slot.
	 */
	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_src);
	res = duk_js_toboolean(tv);  /* does not modify 'tv' */
	DUK_ASSERT(res == 0 || res == 1);
	res ^= 1;
	tv = DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst);
	/* XXX: size optimize: push+replace? */
	DUK_TVAL_SET_BOOLEAN_UPDREF(thr, tv, res);  /* side effects */
}

/* XXX: size optimized variant */
DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__prepost_incdec_reg_helper(duk_hthread *thr, duk_tval *tv_dst, duk_tval *tv_src, duk_small_uint_t op) {
	duk_double_t x, y, z;

	/* Two lowest bits of opcode are used to distinguish
	 * variants.  Bit 0 = inc(0)/dec(1), bit 1 = pre(0)/post(1).
	 */
	DUK_ASSERT((DUK_OP_PREINCR & 0x03) == 0x00);
	DUK_ASSERT((DUK_OP_PREDECR & 0x03) == 0x01);
	DUK_ASSERT((DUK_OP_POSTINCR & 0x03) == 0x02);
	DUK_ASSERT((DUK_OP_POSTDECR & 0x03) == 0x03);

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_src)) {
		duk_int64_t x_fi, y_fi, z_fi;
		x_fi = DUK_TVAL_GET_FASTINT(tv_src);
		if (op & 0x01) {
			if (DUK_UNLIKELY(x_fi == DUK_FASTINT_MIN)) {
				goto skip_fastint;
			}
			y_fi = x_fi - 1;
		} else {
			if (DUK_UNLIKELY(x_fi == DUK_FASTINT_MAX)) {
				goto skip_fastint;
			}
			y_fi = x_fi + 1;
		}

		DUK_TVAL_SET_FASTINT(tv_src, y_fi);  /* no need for refcount update */

		z_fi = (op & 0x02) ? x_fi : y_fi;
		DUK_TVAL_SET_FASTINT_UPDREF(thr, tv_dst, z_fi);  /* side effects */
		return;
	}
 skip_fastint:
#endif
	if (DUK_TVAL_IS_NUMBER(tv_src)) {
		/* Fast path for the case where the register
		 * is a number (e.g. loop counter).
		 */

		x = DUK_TVAL_GET_NUMBER(tv_src);
		if (op & 0x01) {
			y = x - 1.0;
		} else {
			y = x + 1.0;
		}

		DUK_TVAL_SET_NUMBER(tv_src, y);  /* no need for refcount update */
	} else {
		/* Preserve duk_tval pointer(s) across a potential valstack
		 * resize by converting them into offsets temporarily.
		 */
		duk_idx_t bc;
		duk_size_t off_dst;

		off_dst = (duk_size_t) ((duk_uint8_t *) tv_dst - (duk_uint8_t *) thr->valstack_bottom);
		bc = (duk_idx_t) (tv_src - thr->valstack_bottom);  /* XXX: pass index explicitly? */
		tv_src = NULL;  /* no longer referenced */

		x = duk_to_number(thr, bc);
		if (op & 0x01) {
			y = x - 1.0;
		} else {
			y = x + 1.0;
		}

		duk_push_number(thr, y);
		duk_replace(thr, bc);

		tv_dst = (duk_tval *) (void *) (((duk_uint8_t *) thr->valstack_bottom) + off_dst);
	}

	z = (op & 0x02) ? x : y;
	DUK_TVAL_SET_NUMBER_UPDREF(thr, tv_dst, z);  /* side effects */
}

DUK_LOCAL DUK_EXEC_ALWAYS_INLINE_PERF void duk__prepost_incdec_var_helper(duk_hthread *thr, duk_small_uint_t idx_dst, duk_tval *tv_id, duk_small_uint_t op, duk_small_uint_t is_strict) {
	duk_activation *act;
	duk_double_t x, y;
	duk_hstring *name;

	/* XXX: The pre/post inc/dec for an identifier lookup is
	 * missing the important fast path where the identifier
	 * has a storage location e.g. in a scope object so that
	 * it can be updated in-place.  In particular, the case
	 * where the identifier has a storage location AND the
	 * previous value is a number should be optimized because
	 * it's side effect free.
	 */

	/* Two lowest bits of opcode are used to distinguish
	 * variants.  Bit 0 = inc(0)/dec(1), bit 1 = pre(0)/post(1).
	 */
	DUK_ASSERT((DUK_OP_PREINCV & 0x03) == 0x00);
	DUK_ASSERT((DUK_OP_PREDECV & 0x03) == 0x01);
	DUK_ASSERT((DUK_OP_POSTINCV & 0x03) == 0x02);
	DUK_ASSERT((DUK_OP_POSTDECV & 0x03) == 0x03);

	DUK_ASSERT(DUK_TVAL_IS_STRING(tv_id));
	name = DUK_TVAL_GET_STRING(tv_id);
	DUK_ASSERT(name != NULL);
	act = thr->callstack_curr;
	(void) duk_js_getvar_activation(thr, act, name, 1 /*throw*/);  /* -> [ ... val this ] */

	/* XXX: Fastint fast path would be useful here.  Also fastints
	 * now lose their fastint status in current handling which is
	 * not intuitive.
	 */

	x = duk_to_number_m2(thr);
	if (op & 0x01) {
		y = x - 1.0;
	} else {
		y = x + 1.0;
	}

	/* [... x this] */

	if (op & 0x02) {
		duk_push_number(thr, y);  /* -> [ ... x this y ] */
		DUK_ASSERT(act == thr->callstack_curr);
		duk_js_putvar_activation(thr, act, name, DUK_GET_TVAL_NEGIDX(thr, -1), is_strict);
		duk_pop_2_unsafe(thr);  /* -> [ ... x ] */
	} else {
		duk_pop_2_unsafe(thr);  /* -> [ ... ] */
		duk_push_number(thr, y);  /* -> [ ... y ] */
		DUK_ASSERT(act == thr->callstack_curr);
		duk_js_putvar_activation(thr, act, name, DUK_GET_TVAL_NEGIDX(thr, -1), is_strict);
	}

#if defined(DUK_USE_EXEC_PREFER_SIZE)
	duk_replace(thr, (duk_idx_t) idx_dst);
#else  /* DUK_USE_EXEC_PREFER_SIZE */
	DUK__REPLACE_TO_TVPTR(thr, DUK_GET_TVAL_POSIDX(thr, (duk_idx_t) idx_dst));
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
}

/*
 *  Longjmp and other control flow transfer for the bytecode executor.
 *
 *  The longjmp handler can handle all longjmp types: error, yield, and
 *  resume (pseudotypes are never actually thrown).
 *
 *  Error policy for longjmp: should not ordinarily throw errors; if errors
 *  occur (e.g. due to out-of-memory) they bubble outwards rather than being
 *  handled recursively.
 */

#define DUK__LONGJMP_RESTART   0  /* state updated, restart bytecode execution */
#define DUK__LONGJMP_RETHROW   1  /* exit bytecode executor by rethrowing an error to caller */

#define DUK__RETHAND_RESTART   0  /* state updated, restart bytecode execution */
#define DUK__RETHAND_FINISHED  1  /* exit bytecode execution with return value */

/* XXX: optimize reconfig valstack operations so that resize, clamp, and setting
 * top are combined into one pass.
 */

/* Reconfigure value stack for return to an ECMAScript function at
 * callstack top (caller unwinds).
 */
DUK_LOCAL void duk__reconfig_valstack_ecma_return(duk_hthread *thr) {
	duk_activation *act;
	duk_hcompfunc *h_func;
	duk_idx_t clamp_top;

	DUK_ASSERT(thr != NULL);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(act) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(act)));

	/* Clamp so that values at 'clamp_top' and above are wiped and won't
	 * retain reachable garbage.  Then extend to 'nregs' because we're
	 * returning to an ECMAScript function.
	 */

	h_func = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);

	thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act->bottom_byteoff);
	DUK_ASSERT(act->retval_byteoff >= act->bottom_byteoff);
	clamp_top = (duk_idx_t) ((act->retval_byteoff - act->bottom_byteoff + sizeof(duk_tval)) / sizeof(duk_tval));  /* +1 = one retval */
	duk_set_top_and_wipe(thr, h_func->nregs, clamp_top);

	DUK_ASSERT((duk_uint8_t *) thr->valstack_end >= (duk_uint8_t *) thr->valstack + act->reserve_byteoff);
	thr->valstack_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act->reserve_byteoff);

	/* XXX: a best effort shrink check would be OK here */
}

/* Reconfigure value stack for an ECMAScript catcher.  Use topmost catcher
 * in 'act'.
 */
DUK_LOCAL void duk__reconfig_valstack_ecma_catcher(duk_hthread *thr, duk_activation *act) {
	duk_catcher *cat;
	duk_hcompfunc *h_func;
	duk_size_t idx_bottom;
	duk_idx_t clamp_top;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(act) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(act)));
	cat = act->cat;
	DUK_ASSERT(cat != NULL);

	h_func = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);

	thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act->bottom_byteoff);
	idx_bottom = (duk_size_t) (thr->valstack_bottom - thr->valstack);
	DUK_ASSERT(cat->idx_base >= idx_bottom);
	clamp_top = (duk_idx_t) (cat->idx_base - idx_bottom + 2);  /* +2 = catcher value, catcher lj_type */
	duk_set_top_and_wipe(thr, h_func->nregs, clamp_top);

	DUK_ASSERT((duk_uint8_t *) thr->valstack_end >= (duk_uint8_t *) thr->valstack + act->reserve_byteoff);
	thr->valstack_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act->reserve_byteoff);

	/* XXX: a best effort shrink check would be OK here */
}

/* Set catcher regs: idx_base+0 = value, idx_base+1 = lj_type.
 * No side effects.
 */
DUK_LOCAL void duk__set_catcher_regs_norz(duk_hthread *thr, duk_catcher *cat, duk_tval *tv_val_unstable, duk_small_uint_t lj_type) {
	duk_tval *tv1;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_val_unstable != NULL);

	tv1 = thr->valstack + cat->idx_base;
	DUK_ASSERT(tv1 < thr->valstack_top);
	DUK_TVAL_SET_TVAL_UPDREF_NORZ(thr, tv1, tv_val_unstable);

	tv1++;
	DUK_ASSERT(tv1 == thr->valstack + cat->idx_base + 1);
	DUK_ASSERT(tv1 < thr->valstack_top);
	DUK_TVAL_SET_U32_UPDREF_NORZ(thr, tv1, (duk_uint32_t) lj_type);
}

DUK_LOCAL void duk__handle_catch_part1(duk_hthread *thr, duk_tval *tv_val_unstable, duk_small_uint_t lj_type, volatile duk_bool_t *out_delayed_catch_setup) {
	duk_activation *act;
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_val_unstable != NULL);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	DUK_DD(DUK_DDPRINT("handle catch, part 1; act=%!A, cat=%!C", act, act->cat));

	DUK_ASSERT(act->cat != NULL);
	DUK_ASSERT(DUK_CAT_GET_TYPE(act->cat) == DUK_CAT_TYPE_TCF);

	/* The part1/part2 split could also be made here at the very top
	 * of catch handling.  Value stack would be reconfigured inside
	 * part2's protection.  Value stack reconfiguration should be free
	 * of allocs, however.
	 */

	duk__set_catcher_regs_norz(thr, act->cat, tv_val_unstable, lj_type);

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	duk__reconfig_valstack_ecma_catcher(thr, act);

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	cat = act->cat;
	DUK_ASSERT(cat != NULL);

	act->curr_pc = cat->pc_base + 0;  /* +0 = catch */

	/*
	 *  If the catch block has an automatic catch variable binding,
	 *  we need to create a lexical environment for it which requires
	 *  allocations.  Move out of "error handling state" before the
	 *  allocations to avoid e.g. out-of-memory errors (leading to
	 *  GH-2022 or similar).
	 */

	if (DUK_CAT_HAS_CATCH_BINDING_ENABLED(cat)) {
		DUK_DDD(DUK_DDDPRINT("catcher has an automatic catch binding, handle in part 2"));
		*out_delayed_catch_setup = 1;
	} else {
		DUK_DDD(DUK_DDDPRINT("catcher has no catch binding"));
	}

	DUK_CAT_CLEAR_CATCH_ENABLED(cat);
}

DUK_LOCAL void duk__handle_catch_part2(duk_hthread *thr) {
	duk_activation *act;
	duk_catcher *cat;
	duk_hdecenv *new_env;

	DUK_ASSERT(thr != NULL);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	DUK_DD(DUK_DDPRINT("handle catch, part 2; act=%!A, cat=%!C", act, act->cat));

	DUK_ASSERT(act->cat != NULL);
	cat = act->cat;
	DUK_ASSERT(cat != NULL);
	DUK_ASSERT(DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_TCF);
	DUK_ASSERT(DUK_CAT_HAS_CATCH_BINDING_ENABLED(cat));
	DUK_ASSERT(thr->valstack + cat->idx_base < thr->valstack_top);

	/*
	 *  Create lexical environment for the catch clause, containing
	 *  a binding for the caught value.
	 *
	 *  The binding is mutable (= writable) but not deletable.
	 *  Step 4 for the catch production in E5 Section 12.14;
	 *  no value is given for CreateMutableBinding 'D' argument,
	 *  which implies the binding is not deletable.
	 */

	if (act->lex_env == NULL) {
		DUK_ASSERT(act->var_env == NULL);
		DUK_DDD(DUK_DDDPRINT("delayed environment initialization"));

		duk_js_init_activation_environment_records_delayed(thr, act);
		DUK_ASSERT(act == thr->callstack_curr);
		DUK_ASSERT(act != NULL);
	}
	DUK_ASSERT(act->lex_env != NULL);
	DUK_ASSERT(act->var_env != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(act) != NULL);

	new_env = duk_hdecenv_alloc(thr,
	                            DUK_HOBJECT_FLAG_EXTENSIBLE |
	                            DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV));
	DUK_ASSERT(new_env != NULL);
	duk_push_hobject(thr, (duk_hobject *) new_env);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) new_env) == NULL);
	DUK_DDD(DUK_DDDPRINT("new_env allocated: %!iO", (duk_heaphdr *) new_env));

	/* Note: currently the catch binding is handled without a register
	 * binding because we don't support dynamic register bindings (they
	 * must be fixed for an entire function).  So, there is no need to
	 * record regbases etc.
	 */

	/* [ ...env ] */

	DUK_ASSERT(cat->h_varname != NULL);
	duk_push_hstring(thr, cat->h_varname);
	DUK_ASSERT(thr->valstack + cat->idx_base < thr->valstack_top);
	duk_push_tval(thr, thr->valstack + cat->idx_base);
	duk_xdef_prop(thr, -3, DUK_PROPDESC_FLAGS_W);  /* writable, not configurable */

	/* [ ... env ] */

	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) new_env, act->lex_env);
	act->lex_env = (duk_hobject *) new_env;
	DUK_HOBJECT_INCREF(thr, (duk_hobject *) new_env);  /* reachable through activation */
	/* Net refcount change to act->lex_env is 0: incref for new_env's
	 * prototype, decref for act->lex_env overwrite.
	 */

	DUK_CAT_SET_LEXENV_ACTIVE(cat);

	duk_pop_unsafe(thr);

	DUK_DDD(DUK_DDDPRINT("new_env finished: %!iO", (duk_heaphdr *) new_env));
}

DUK_LOCAL void duk__handle_finally(duk_hthread *thr, duk_tval *tv_val_unstable, duk_small_uint_t lj_type) {
	duk_activation *act;
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv_val_unstable != NULL);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(act->cat != NULL);
	DUK_ASSERT(DUK_CAT_GET_TYPE(act->cat) == DUK_CAT_TYPE_TCF);

	duk__set_catcher_regs_norz(thr, act->cat, tv_val_unstable, lj_type);

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	duk__reconfig_valstack_ecma_catcher(thr, act);

	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	cat = act->cat;
	DUK_ASSERT(cat != NULL);

	act->curr_pc = cat->pc_base + 1;  /* +1 = finally */

	DUK_CAT_CLEAR_FINALLY_ENABLED(cat);
}

DUK_LOCAL void duk__handle_label(duk_hthread *thr, duk_small_uint_t lj_type) {
	duk_activation *act;
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);

	DUK_ASSERT(thr->callstack_top >= 1);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(act) != NULL);
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(DUK_ACT_GET_FUNC(act)));

	/* +0 = break, +1 = continue */
	cat = act->cat;
	DUK_ASSERT(cat != NULL);
	DUK_ASSERT(DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_LABEL);

	act->curr_pc = cat->pc_base + (lj_type == DUK_LJ_TYPE_CONTINUE ? 1 : 0);

	/* valstack should not need changes */
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(act == thr->callstack_curr);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack_bottom) ==
	           (duk_size_t) ((duk_hcompfunc *) DUK_ACT_GET_FUNC(act))->nregs);
#endif
}

/* Called for handling both a longjmp() with type DUK_LJ_TYPE_YIELD and
 * when a RETURN opcode terminates a thread and yields to the resumer.
 * Caller unwinds so that top of callstack is the activation we return to.
 */
#if defined(DUK_USE_COROUTINE_SUPPORT)
DUK_LOCAL void duk__handle_yield(duk_hthread *thr, duk_hthread *resumer, duk_tval *tv_val_unstable) {
	duk_activation *act_resumer;
	duk_tval *tv1;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(resumer != NULL);
	DUK_ASSERT(tv_val_unstable != NULL);
	act_resumer = resumer->callstack_curr;
	DUK_ASSERT(act_resumer != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(act_resumer) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(act_resumer)));  /* resume caller must be an ECMAScript func */

	tv1 = (duk_tval *) (void *) ((duk_uint8_t *) resumer->valstack + act_resumer->retval_byteoff);  /* return value from Duktape.Thread.resume() */
	DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv_val_unstable);  /* side effects */  /* XXX: avoid side effects */

	duk__reconfig_valstack_ecma_return(resumer);

	/* caller must change active thread, and set thr->resumer to NULL */
}
#endif  /* DUK_USE_COROUTINE_SUPPORT */

DUK_LOCAL duk_small_uint_t duk__handle_longjmp(duk_hthread *thr, duk_activation *entry_act, volatile duk_bool_t *out_delayed_catch_setup) {
	duk_small_uint_t retval = DUK__LONGJMP_RESTART;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(entry_act != NULL);

	/* 'thr' is the current thread, as no-one resumes except us and we
	 * switch 'thr' in that case.
	 */
	DUK_ASSERT(thr == thr->heap->curr_thread);

	/*
	 *  (Re)try handling the longjmp.
	 *
	 *  A longjmp handler may convert the longjmp to a different type and
	 *  "virtually" rethrow by goto'ing to 'check_longjmp'.  Before the goto,
	 *  the following must be updated:
	 *    - the heap 'lj' state
	 *    - 'thr' must reflect the "throwing" thread
	 */

 check_longjmp:

	DUK_DD(DUK_DDPRINT("handling longjmp: type=%ld, value1=%!T, value2=%!T, iserror=%ld, top=%ld",
	                   (long) thr->heap->lj.type,
	                   (duk_tval *) &thr->heap->lj.value1,
	                   (duk_tval *) &thr->heap->lj.value2,
	                   (long) thr->heap->lj.iserror,
			   (long) duk_get_top(thr)));

	switch (thr->heap->lj.type) {

#if defined(DUK_USE_COROUTINE_SUPPORT)
	case DUK_LJ_TYPE_RESUME: {
		/*
		 *  Note: lj.value1 is 'value', lj.value2 is 'resumee'.
		 *  This differs from YIELD.
		 */

		duk_tval *tv;
		duk_tval *tv2;
		duk_hthread *resumee;

		/* duk_bi_duk_object_yield() and duk_bi_duk_object_resume() ensure all of these are met */

		DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);                                                         /* unchanged by Duktape.Thread.resume() */
		DUK_ASSERT(thr->callstack_top >= 2);                                                                         /* ECMAScript activation + Duktape.Thread.resume() activation */
		DUK_ASSERT(thr->callstack_curr != NULL);
		DUK_ASSERT(thr->callstack_curr->parent != NULL);
		DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL &&
		           DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)) &&
		           ((duk_hnatfunc *) DUK_ACT_GET_FUNC(thr->callstack_curr))->func == duk_bi_thread_resume);

		tv = &thr->heap->lj.value2;  /* resumee */
		DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
		DUK_ASSERT(DUK_TVAL_GET_OBJECT(tv) != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_THREAD(DUK_TVAL_GET_OBJECT(tv)));
		resumee = (duk_hthread *) DUK_TVAL_GET_OBJECT(tv);

		DUK_ASSERT(resumee != NULL);
		DUK_ASSERT(resumee->resumer == NULL);
		DUK_ASSERT(resumee->state == DUK_HTHREAD_STATE_INACTIVE ||
		           resumee->state == DUK_HTHREAD_STATE_YIELDED);                                                     /* checked by Duktape.Thread.resume() */
		DUK_ASSERT(resumee->state != DUK_HTHREAD_STATE_YIELDED ||
		           resumee->callstack_top >= 2);                                                                     /* YIELDED: ECMAScript activation + Duktape.Thread.yield() activation */
		DUK_ASSERT(resumee->state != DUK_HTHREAD_STATE_YIELDED ||
		           (DUK_ACT_GET_FUNC(resumee->callstack_curr) != NULL &&
		            DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(resumee->callstack_curr)) &&
		            ((duk_hnatfunc *) DUK_ACT_GET_FUNC(resumee->callstack_curr))->func == duk_bi_thread_yield));
		DUK_ASSERT(resumee->state != DUK_HTHREAD_STATE_INACTIVE ||
		           resumee->callstack_top == 0);                                                                     /* INACTIVE: no activation, single function value on valstack */

		if (thr->heap->lj.iserror) {
			/*
			 *  Throw the error in the resumed thread's context; the
			 *  error value is pushed onto the resumee valstack.
			 *
			 *  Note: the callstack of the target may empty in this case
			 *  too (i.e. the target thread has never been resumed).  The
			 *  value stack will contain the initial function in that case,
			 *  which we simply ignore.
			 */

			DUK_ASSERT(resumee->resumer == NULL);
			resumee->resumer = thr;
			DUK_HTHREAD_INCREF(thr, thr);
			resumee->state = DUK_HTHREAD_STATE_RUNNING;
			thr->state = DUK_HTHREAD_STATE_RESUMED;
			DUK_HEAP_SWITCH_THREAD(thr->heap, resumee);
			thr = resumee;

			thr->heap->lj.type = DUK_LJ_TYPE_THROW;

			/* thr->heap->lj.value1 is already the value to throw */
			/* thr->heap->lj.value2 is 'thread', will be wiped out at the end */

			DUK_ASSERT(thr->heap->lj.iserror);  /* already set */

			DUK_DD(DUK_DDPRINT("-> resume with an error, converted to a throw in the resumee, propagate"));
			goto check_longjmp;
		} else if (resumee->state == DUK_HTHREAD_STATE_YIELDED) {
			/* Unwind previous Duktape.Thread.yield() call.  The
			 * activation remaining must always be an ECMAScript
			 * call now (yield() accepts calls from ECMAScript
			 * only).
			 */
			duk_activation *act_resumee;

			DUK_ASSERT(resumee->callstack_top >= 2);
			act_resumee = resumee->callstack_curr;  /* Duktape.Thread.yield() */
			DUK_ASSERT(act_resumee != NULL);
			act_resumee = act_resumee->parent;      /* ECMAScript call site for yield() */
			DUK_ASSERT(act_resumee != NULL);

			tv = (duk_tval *) (void *) ((duk_uint8_t *) resumee->valstack + act_resumee->retval_byteoff);  /* return value from Duktape.Thread.yield() */
			DUK_ASSERT(tv >= resumee->valstack && tv < resumee->valstack_top);
			tv2 = &thr->heap->lj.value1;
			DUK_TVAL_SET_TVAL_UPDREF(thr, tv, tv2);  /* side effects */  /* XXX: avoid side effects */

			duk_hthread_activation_unwind_norz(resumee);  /* unwind to 'yield' caller */
			/* no need to unwind catch stack */

			duk__reconfig_valstack_ecma_return(resumee);

			DUK_ASSERT(resumee->resumer == NULL);
			resumee->resumer = thr;
			DUK_HTHREAD_INCREF(thr, thr);
			resumee->state = DUK_HTHREAD_STATE_RUNNING;
			thr->state = DUK_HTHREAD_STATE_RESUMED;
			DUK_HEAP_SWITCH_THREAD(thr->heap, resumee);
#if 0
			thr = resumee;  /* not needed, as we exit right away */
#endif
			DUK_DD(DUK_DDPRINT("-> resume with a value, restart execution in resumee"));
			retval = DUK__LONGJMP_RESTART;
			goto wipe_and_return;
		} else {
			/* Initial resume call. */
			duk_small_uint_t call_flags;
			duk_int_t setup_rc;

			/* resumee: [... initial_func]  (currently actually: [initial_func]) */

			duk_push_undefined(resumee);
			tv = &thr->heap->lj.value1;
			duk_push_tval(resumee, tv);

			/* resumee: [... initial_func undefined(= this) resume_value ] */

			call_flags = DUK_CALL_FLAG_ALLOW_ECMATOECMA;  /* not tailcall, ecma-to-ecma (assumed to succeed) */

			setup_rc = duk_handle_call_unprotected_nargs(resumee, 1 /*nargs*/, call_flags);
			if (setup_rc == 0) {
				/* This shouldn't happen; Duktape.Thread.resume()
				 * should make sure of that.  If it does happen
				 * this internal error will propagate out of the
				 * executor which can be quite misleading.
				 */
				DUK_ERROR_INTERNAL(thr);
				DUK_WO_NORETURN(return 0;);
			}

			DUK_ASSERT(resumee->resumer == NULL);
			resumee->resumer = thr;
			DUK_HTHREAD_INCREF(thr, thr);
			resumee->state = DUK_HTHREAD_STATE_RUNNING;
			thr->state = DUK_HTHREAD_STATE_RESUMED;
			DUK_HEAP_SWITCH_THREAD(thr->heap, resumee);
#if 0
			thr = resumee;  /* not needed, as we exit right away */
#endif
			DUK_DD(DUK_DDPRINT("-> resume with a value, restart execution in resumee"));
			retval = DUK__LONGJMP_RESTART;
			goto wipe_and_return;
		}
		DUK_UNREACHABLE();
		break;  /* never here */
	}

	case DUK_LJ_TYPE_YIELD: {
		/*
		 *  Currently only allowed only if yielding thread has only
		 *  ECMAScript activations (except for the Duktape.Thread.yield()
		 *  call at the callstack top) and none of them constructor
		 *  calls.
		 *
		 *  This excludes the 'entry' thread which will always have
		 *  a preventcount > 0.
		 */

		duk_hthread *resumer;

		/* duk_bi_duk_object_yield() and duk_bi_duk_object_resume() ensure all of these are met */

#if 0  /* entry_thread not available for assert */
		DUK_ASSERT(thr != entry_thread);                                                                             /* Duktape.Thread.yield() should prevent */
#endif
		DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);                                                         /* unchanged from Duktape.Thread.yield() */
		DUK_ASSERT(thr->callstack_top >= 2);                                                                         /* ECMAScript activation + Duktape.Thread.yield() activation */
		DUK_ASSERT(thr->callstack_curr != NULL);
		DUK_ASSERT(thr->callstack_curr->parent != NULL);
		DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL &&
		           DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)) &&
		           ((duk_hnatfunc *) DUK_ACT_GET_FUNC(thr->callstack_curr))->func == duk_bi_thread_yield);
		DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr->parent) != NULL &&
		           DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr->parent)));                              /* an ECMAScript function */

		resumer = thr->resumer;

		DUK_ASSERT(resumer != NULL);
		DUK_ASSERT(resumer->state == DUK_HTHREAD_STATE_RESUMED);                                                     /* written by a previous RESUME handling */
		DUK_ASSERT(resumer->callstack_top >= 2);                                                                     /* ECMAScript activation + Duktape.Thread.resume() activation */
		DUK_ASSERT(resumer->callstack_curr != NULL);
		DUK_ASSERT(resumer->callstack_curr->parent != NULL);
		DUK_ASSERT(DUK_ACT_GET_FUNC(resumer->callstack_curr) != NULL &&
		           DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(resumer->callstack_curr)) &&
		           ((duk_hnatfunc *) DUK_ACT_GET_FUNC(resumer->callstack_curr))->func == duk_bi_thread_resume);
		DUK_ASSERT(DUK_ACT_GET_FUNC(resumer->callstack_curr->parent) != NULL &&
		           DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(resumer->callstack_curr->parent)));                            /* an ECMAScript function */

		if (thr->heap->lj.iserror) {
			thr->state = DUK_HTHREAD_STATE_YIELDED;
			thr->resumer = NULL;
			DUK_HTHREAD_DECREF_NORZ(thr, resumer);
			resumer->state = DUK_HTHREAD_STATE_RUNNING;
			DUK_HEAP_SWITCH_THREAD(thr->heap, resumer);
			thr = resumer;

			thr->heap->lj.type = DUK_LJ_TYPE_THROW;
			/* lj.value1 is already set */
			DUK_ASSERT(thr->heap->lj.iserror);  /* already set */

			DUK_DD(DUK_DDPRINT("-> yield an error, converted to a throw in the resumer, propagate"));
			goto check_longjmp;
		} else {
			duk_hthread_activation_unwind_norz(resumer);
			duk__handle_yield(thr, resumer, &thr->heap->lj.value1);

			thr->state = DUK_HTHREAD_STATE_YIELDED;
			thr->resumer = NULL;
			DUK_HTHREAD_DECREF_NORZ(thr, resumer);
			resumer->state = DUK_HTHREAD_STATE_RUNNING;
			DUK_HEAP_SWITCH_THREAD(thr->heap, resumer);
#if 0
			thr = resumer;  /* not needed, as we exit right away */
#endif

			DUK_DD(DUK_DDPRINT("-> yield a value, restart execution in resumer"));
			retval = DUK__LONGJMP_RESTART;
			goto wipe_and_return;
		}
		DUK_UNREACHABLE();
		break;  /* never here */
	}
#endif  /* DUK_USE_COROUTINE_SUPPORT */

	case DUK_LJ_TYPE_THROW: {
		/*
		 *  Three possible outcomes:
		 *    * A try or finally catcher is found => resume there.
		 *      (or)
		 *    * The error propagates to the bytecode executor entry
		 *      level (and we're in the entry thread) => rethrow
		 *      with a new longjmp(), after restoring the previous
		 *      catchpoint.
		 *    * The error is not caught in the current thread, so
		 *      the thread finishes with an error.  This works like
		 *      a yielded error, except that the thread is finished
		 *      and can no longer be resumed.  (There is always a
		 *      resumer in this case.)
		 *
		 *  Note: until we hit the entry level, there can only be
		 *  ECMAScript activations.
		 */

		duk_activation *act;
		duk_catcher *cat;
		duk_hthread *resumer;

		for (;;) {
			act = thr->callstack_curr;
			if (act == NULL) {
				break;
			}

			for (;;) {
				cat = act->cat;
				if (cat == NULL) {
					break;
				}

				if (DUK_CAT_HAS_CATCH_ENABLED(cat)) {
					DUK_ASSERT(DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_TCF);

					DUK_DDD(DUK_DDDPRINT("before catch part 1: thr=%p, act=%p, cat=%p",
					                     (void *) thr, (void *) act, (void *) act->cat));
					duk__handle_catch_part1(thr,
					                        &thr->heap->lj.value1,
					                        DUK_LJ_TYPE_THROW,
							        out_delayed_catch_setup);

					DUK_DD(DUK_DDPRINT("-> throw caught by a 'catch' clause, restart execution"));
					retval = DUK__LONGJMP_RESTART;
					goto wipe_and_return;
				}

				if (DUK_CAT_HAS_FINALLY_ENABLED(cat)) {
					DUK_ASSERT(DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_TCF);
					DUK_ASSERT(!DUK_CAT_HAS_CATCH_ENABLED(cat));

					duk__handle_finally(thr,
					                    &thr->heap->lj.value1,
					                    DUK_LJ_TYPE_THROW);

					DUK_DD(DUK_DDPRINT("-> throw caught by a 'finally' clause, restart execution"));
					retval = DUK__LONGJMP_RESTART;
					goto wipe_and_return;
				}

				duk_hthread_catcher_unwind_norz(thr, act);
			}

			if (act == entry_act) {
				/* Not caught by anything before entry level; rethrow and let the
				 * final catcher finish unwinding (esp. value stack).
				 */
				DUK_D(DUK_DPRINT("-> throw propagated up to entry level, rethrow and exit bytecode executor"));
				retval = DUK__LONGJMP_RETHROW;
				goto just_return;
			}

			duk_hthread_activation_unwind_norz(thr);
		}

		DUK_DD(DUK_DDPRINT("-> throw not caught by current thread, yield error to resumer and recheck longjmp"));

		/* Not caught by current thread, thread terminates (yield error to resumer);
		 * note that this may cause a cascade if the resumer terminates with an uncaught
		 * exception etc (this is OK, but needs careful testing).
		 */

		DUK_ASSERT(thr->resumer != NULL);
		DUK_ASSERT(thr->resumer->callstack_top >= 2);  /* ECMAScript activation + Duktape.Thread.resume() activation */
		DUK_ASSERT(thr->resumer->callstack_curr != NULL);
		DUK_ASSERT(thr->resumer->callstack_curr->parent != NULL);
		DUK_ASSERT(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr->parent) != NULL &&
		           DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr->parent)));  /* an ECMAScript function */

		resumer = thr->resumer;

		/* reset longjmp */

		DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_THROW);  /* already set */
		/* lj.value1 already set */

		duk_hthread_terminate(thr);  /* updates thread state, minimizes its allocations */
		DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_TERMINATED);

		thr->resumer = NULL;
		DUK_HTHREAD_DECREF_NORZ(thr, resumer);
		resumer->state = DUK_HTHREAD_STATE_RUNNING;
		DUK_HEAP_SWITCH_THREAD(thr->heap, resumer);
		thr = resumer;
		goto check_longjmp;
	}

	case DUK_LJ_TYPE_BREAK:  /* pseudotypes, not used in actual longjmps */
	case DUK_LJ_TYPE_CONTINUE:
	case DUK_LJ_TYPE_RETURN:
	case DUK_LJ_TYPE_NORMAL:
	default: {
		/* should never happen, but be robust */
		DUK_D(DUK_DPRINT("caught unknown longjmp type %ld, treat as internal error", (long) thr->heap->lj.type));
		goto convert_to_internal_error;
	}

	}  /* end switch */

	DUK_UNREACHABLE();

 wipe_and_return:
	DUK_DD(DUK_DDPRINT("handling longjmp done, wipe-and-return, top=%ld",
	                   (long) duk_get_top(thr)));
	thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
	thr->heap->lj.iserror = 0;

	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value1);  /* side effects */
	DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value2);  /* side effects */

	DUK_GC_TORTURE(thr->heap);

 just_return:
	return retval;

 convert_to_internal_error:
	/* This could also be thrown internally (set the error, goto check_longjmp),
	 * but it's better for internal errors to bubble outwards so that we won't
	 * infinite loop in this catchpoint.
	 */
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return 0;);
}

/* Handle a BREAK/CONTINUE opcode.  Avoid using longjmp() for BREAK/CONTINUE
 * handling because it has a measurable performance impact in ordinary
 * environments and an extreme impact in Emscripten (GH-342).
 */
DUK_LOCAL DUK_EXEC_NOINLINE_PERF void duk__handle_break_or_continue(duk_hthread *thr,
                                                                    duk_uint_t label_id,
                                                                    duk_small_uint_t lj_type) {
	duk_activation *act;
	duk_catcher *cat;

	DUK_ASSERT(thr != NULL);

	/* Find a matching label catcher or 'finally' catcher in
	 * the same function, unwinding catchers as we go.
	 *
	 * A label catcher must always exist and will match unless
	 * a 'finally' captures the break/continue first.  It is the
	 * compiler's responsibility to ensure that labels are used
	 * correctly.
	 */

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);

	for (;;) {
		cat = act->cat;
		if (cat == NULL) {
			break;
		}

		DUK_DDD(DUK_DDDPRINT("considering catcher %p: type=%ld label=%ld",
		                     (void *) cat,
		                     (long) DUK_CAT_GET_TYPE(cat),
		                     (long) DUK_CAT_GET_LABEL(cat)));

		/* XXX: bit mask test; FINALLY <-> TCF, single bit mask would suffice? */

		if (DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_TCF &&
		    DUK_CAT_HAS_FINALLY_ENABLED(cat)) {
			duk_tval tv_tmp;

			DUK_TVAL_SET_U32(&tv_tmp, (duk_uint32_t) label_id);
			duk__handle_finally(thr, &tv_tmp, lj_type);

			DUK_DD(DUK_DDPRINT("-> break/continue caught by 'finally', restart execution"));
			return;
		}
		if (DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_LABEL &&
		    (duk_uint_t) DUK_CAT_GET_LABEL(cat) == label_id) {
			duk__handle_label(thr, lj_type);

			DUK_DD(DUK_DDPRINT("-> break/continue caught by a label catcher (in the same function), restart execution"));
			return;
		}

		duk_hthread_catcher_unwind_norz(thr, act);
	}

	/* Should never happen, but be robust. */
	DUK_D(DUK_DPRINT("-> break/continue not caught by anything in the current function (should never happen), throw internal error"));
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return;);
}

/* Handle a RETURN opcode.  Avoid using longjmp() for return handling because
 * it has a measurable performance impact in ordinary environments and an extreme
 * impact in Emscripten (GH-342).  Return value is on value stack top.
 */
DUK_LOCAL duk_small_uint_t duk__handle_return(duk_hthread *thr, duk_activation *entry_act) {
	duk_tval *tv1;
	duk_tval *tv2;
#if defined(DUK_USE_COROUTINE_SUPPORT)
	duk_hthread *resumer;
#endif
	duk_activation *act;
	duk_catcher *cat;

	/* We can directly access value stack here. */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(entry_act != NULL);
	DUK_ASSERT(thr->valstack_top - 1 >= thr->valstack_bottom);
	tv1 = thr->valstack_top - 1;
	DUK_TVAL_CHKFAST_INPLACE_FAST(tv1);  /* fastint downgrade check for return values */

	/*
	 *  Four possible outcomes:
	 *
	 *    1. A 'finally' in the same function catches the 'return'.
	 *       It may continue to propagate when 'finally' is finished,
	 *       or it may be neutralized by 'finally' (both handled by
	 *       ENDFIN).
	 *
	 *    2. The return happens at the entry level of the bytecode
	 *       executor, so return from the executor (in C stack).
	 *
	 *    3. There is a calling (ECMAScript) activation in the call
	 *       stack => return to it, in the same executor instance.
	 *
	 *    4. There is no calling activation, and the thread is
	 *       terminated.  There is always a resumer in this case,
	 *       which gets the return value similarly to a 'yield'
	 *       (except that the current thread can no longer be
	 *       resumed).
	 */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->callstack_top >= 1);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);

	for (;;) {
		cat = act->cat;
		if (cat == NULL) {
			break;
		}

		if (DUK_CAT_GET_TYPE(cat) == DUK_CAT_TYPE_TCF &&
		    DUK_CAT_HAS_FINALLY_ENABLED(cat)) {
			DUK_ASSERT(thr->valstack_top - 1 >= thr->valstack_bottom);
			duk__handle_finally(thr, thr->valstack_top - 1, DUK_LJ_TYPE_RETURN);

			DUK_DD(DUK_DDPRINT("-> return caught by 'finally', restart execution"));
			return DUK__RETHAND_RESTART;
		}

		duk_hthread_catcher_unwind_norz(thr, act);
	}

	if (act == entry_act) {
		/* Return to the bytecode executor caller who will unwind stacks
		 * and handle constructor post-processing.
		 * Return value is already on the stack top: [ ... retval ].
		 */

		DUK_DDD(DUK_DDDPRINT("-> return propagated up to entry level, exit bytecode executor"));
		return DUK__RETHAND_FINISHED;
	}

	if (thr->callstack_top >= 2) {
		/* There is a caller; it MUST be an ECMAScript caller (otherwise it would
		 * match entry_act check).
		 */
		DUK_DDD(DUK_DDDPRINT("return to ECMAScript caller, retval_byteoff=%ld, lj_value1=%!T",
		                     (long) (thr->callstack_curr->parent->retval_byteoff),
		                     (duk_tval *) &thr->heap->lj.value1));

		DUK_ASSERT(thr->callstack_curr != NULL);
		DUK_ASSERT(thr->callstack_curr->parent != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr->parent)));   /* must be ECMAScript */

#if defined(DUK_USE_ES6_PROXY)
		if (thr->callstack_curr->flags & (DUK_ACT_FLAG_CONSTRUCT | DUK_ACT_FLAG_CONSTRUCT_PROXY)) {
			duk_call_construct_postprocess(thr, thr->callstack_curr->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY);  /* side effects */
		}
#else
		if (thr->callstack_curr->flags & DUK_ACT_FLAG_CONSTRUCT) {
			duk_call_construct_postprocess(thr, 0);  /* side effects */
		}
#endif

		tv1 = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + thr->callstack_curr->parent->retval_byteoff);
		DUK_ASSERT(thr->valstack_top - 1 >= thr->valstack_bottom);
		tv2 = thr->valstack_top - 1;
		DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2);  /* side effects */

		/* Catch stack unwind happens inline in callstack unwind. */
		duk_hthread_activation_unwind_norz(thr);

		duk__reconfig_valstack_ecma_return(thr);

		DUK_DD(DUK_DDPRINT("-> return not intercepted, restart execution in caller"));
		return DUK__RETHAND_RESTART;
	}

#if defined(DUK_USE_COROUTINE_SUPPORT)
	DUK_DD(DUK_DDPRINT("no calling activation, thread finishes (similar to yield)"));

	DUK_ASSERT(thr->resumer != NULL);
	DUK_ASSERT(thr->resumer->callstack_top >= 2);  /* ECMAScript activation + Duktape.Thread.resume() activation */
	DUK_ASSERT(thr->resumer->callstack_curr != NULL);
	DUK_ASSERT(thr->resumer->callstack_curr->parent != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr) != NULL &&
			DUK_HOBJECT_IS_NATFUNC(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr)) &&
			((duk_hnatfunc *) DUK_ACT_GET_FUNC(thr->resumer->callstack_curr))->func == duk_bi_thread_resume);  /* Duktape.Thread.resume() */
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr->parent) != NULL &&
			DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->resumer->callstack_curr->parent)));  /* an ECMAScript function */
	DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
	DUK_ASSERT(thr->resumer->state == DUK_HTHREAD_STATE_RESUMED);

	resumer = thr->resumer;

	/* Share yield longjmp handler.
	 *
	 * This sequence of steps is a bit fragile (see GH-1845):
	 * - We need the return value from 'thr' (resumed thread) value stack.
	 *   The termination unwinds its value stack, losing the value.
	 * - We need a refcounted reference for 'thr', which may only exist
	 *   in the caller value stack.  We can't unwind or reconfigure the
	 *   caller's value stack without potentially freeing 'thr'.
	 *
	 * Current approach is to capture the 'thr' return value and store
	 * a reference to 'thr' in the caller value stack temporarily.  This
	 * keeps 'thr' reachable until final yield/return handling which
	 * removes the references atomatically.
	 */

	DUK_ASSERT(thr->valstack_top - 1 >= thr->valstack_bottom);
	duk_hthread_activation_unwind_norz(resumer);  /* May remove last reference to 'thr', but is NORZ. */
	duk_push_tval(resumer, thr->valstack_top - 1);  /* Capture return value, side effect free. */
	duk_push_hthread(resumer, thr);  /* Make 'thr' reachable again, before side effects. */

	duk_hthread_terminate(thr);  /* Updates thread state, minimizes its allocations. */
	thr->resumer = NULL;
	DUK_HTHREAD_DECREF(thr, resumer);
	DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_TERMINATED);

	resumer->state = DUK_HTHREAD_STATE_RUNNING;
	DUK_HEAP_SWITCH_THREAD(thr->heap, resumer);

	DUK_ASSERT(resumer->valstack_top - 2 >= resumer->valstack_bottom);
	duk__handle_yield(thr, resumer, resumer->valstack_top - 2);
	thr = NULL;  /* 'thr' invalidated by call */

#if 0
	thr = resumer;  /* not needed */
#endif

	DUK_DD(DUK_DDPRINT("-> return not caught, thread terminated; handle like yield, restart execution in resumer"));
	return DUK__RETHAND_RESTART;
#else
	/* Without coroutine support this case should never happen. */
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return 0;);
#endif
}

/*
 *  Executor interrupt handling
 *
 *  The handler is called whenever the interrupt countdown reaches zero
 *  (or below).  The handler must perform whatever checks are activated,
 *  e.g. check for cumulative step count to impose an execution step
 *  limit or check for breakpoints or other debugger interaction.
 *
 *  When the actions are done, the handler must reinit the interrupt
 *  init and counter values.  The 'init' value must indicate how many
 *  bytecode instructions are executed before the next interrupt.  The
 *  counter must interface with the bytecode executor loop.  Concretely,
 *  the new init value is normally one higher than the new counter value.
 *  For instance, to execute exactly one bytecode instruction the init
 *  value is set to 1 and the counter to 0.  If an error is thrown by the
 *  interrupt handler, the counters are set to the same value (e.g. both
 *  to 0 to cause an interrupt when the next bytecode instruction is about
 *  to be executed after error handling).
 *
 *  Maintaining the init/counter value properly is important for accurate
 *  behavior.  For instance, executor step limit needs a cumulative step
 *  count which is simply computed as a sum of 'init' values.  This must
 *  work accurately even when single stepping.
 */

#if defined(DUK_USE_INTERRUPT_COUNTER)

#define DUK__INT_NOACTION    0    /* no specific action, resume normal execution */
#define DUK__INT_RESTART     1    /* must "goto restart_execution", e.g. breakpoints changed */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_LOCAL void duk__interrupt_handle_debugger(duk_hthread *thr, duk_bool_t *out_immediate, duk_small_uint_t *out_interrupt_retval) {
	duk_activation *act;
	duk_breakpoint *bp;
	duk_breakpoint **bp_active;
	duk_uint_fast32_t line = 0;
	duk_bool_t process_messages;
	duk_bool_t processed_messages = 0;

	DUK_ASSERT(thr->heap->dbg_processing == 0);  /* don't re-enter e.g. during Eval */

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);

	/* It might seem that replacing 'thr->heap' with just 'heap' below
	 * might be a good idea, but it increases code size slightly
	 * (probably due to unnecessary spilling) at least on x64.
	 */

	/*
	 *  Single opcode step check
	 */

	if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_ONE_OPCODE_ACTIVE) {
		DUK_D(DUK_DPRINT("PAUSE TRIGGERED by one opcode step"));
		duk_debug_set_paused(thr->heap);
	}

	/*
	 *  Breakpoint and step state checks
	 */

	if (act->flags & DUK_ACT_FLAG_BREAKPOINT_ACTIVE ||
	    (thr->heap->dbg_pause_act == thr->callstack_curr)) {
		line = duk_debug_curr_line(thr);

		if (act->prev_line != line) {
			/* Stepped?  Step out is handled by callstack unwind. */
			if ((thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_LINE_CHANGE) &&
			    (thr->heap->dbg_pause_act == thr->callstack_curr) &&
			    (line != thr->heap->dbg_pause_startline)) {
				DUK_D(DUK_DPRINT("PAUSE TRIGGERED by line change, at line %ld",
				                 (long) line));
				duk_debug_set_paused(thr->heap);
			}

			/* Check for breakpoints only on line transition.
			 * Breakpoint is triggered when we enter the target
			 * line from a different line, and the previous line
			 * was within the same function.
			 *
			 * This condition is tricky: the condition used to be
			 * that transition to -or across- the breakpoint line
			 * triggered the breakpoint.  This seems intuitively
			 * better because it handles breakpoints on lines with
			 * no emitted opcodes; but this leads to the issue
			 * described in: https://github.com/svaarala/duktape/issues/263.
			 */
			bp_active = thr->heap->dbg_breakpoints_active;
			for (;;) {
				bp = *bp_active++;
				if (bp == NULL) {
					break;
				}

				DUK_ASSERT(bp->filename != NULL);
				if (act->prev_line != bp->line && line == bp->line) {
					DUK_D(DUK_DPRINT("PAUSE TRIGGERED by breakpoint at %!O:%ld",
					                 (duk_heaphdr *) bp->filename, (long) bp->line));
					duk_debug_set_paused(thr->heap);
				}
			}
		} else {
			;
		}

		act->prev_line = (duk_uint32_t) line;
	}

	/*
	 *  Rate limit check for sending status update or peeking into
	 *  the debug transport.  Both can be expensive operations that
	 *  we don't want to do on every opcode.
	 *
	 *  Making sure the interval remains reasonable on a wide variety
	 *  of targets and bytecode is difficult without a timestamp, so
	 *  we use a Date-provided timestamp for the rate limit check.
	 *  But since it's also expensive to get a timestamp, a bytecode
	 *  counter is used to rate limit getting timestamps.
	 */

	process_messages = 0;
	if (thr->heap->dbg_state_dirty || DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap) || thr->heap->dbg_detaching) {
		/* Enter message processing loop for sending Status notifys and
		 * to finish a pending detach.
		 */
		process_messages = 1;
	}

	/* XXX: remove heap->dbg_exec_counter, use heap->inst_count_interrupt instead? */
	DUK_ASSERT(thr->interrupt_init >= 0);
	thr->heap->dbg_exec_counter += (duk_uint_t) thr->interrupt_init;
	if (thr->heap->dbg_exec_counter - thr->heap->dbg_last_counter >= DUK_HEAP_DBG_RATELIMIT_OPCODES) {
		/* Overflow of the execution counter is fine and doesn't break
		 * anything here.
		 */

		duk_double_t now, diff_last;

		thr->heap->dbg_last_counter = thr->heap->dbg_exec_counter;
		now = duk_time_get_monotonic_time(thr);

		diff_last = now - thr->heap->dbg_last_time;
		if (diff_last < 0.0 || diff_last >= (duk_double_t) DUK_HEAP_DBG_RATELIMIT_MILLISECS) {
			/* Monotonic time should not experience time jumps,
			 * but the provider may be missing and we're actually
			 * using ECMAScript time.  So, tolerate negative values
			 * so that a time jump works reasonably.
			 *
			 * Same interval is now used for status sending and
			 * peeking.
			 */

			thr->heap->dbg_last_time = now;
			thr->heap->dbg_state_dirty = 1;
			process_messages = 1;
		}
	}

	/*
	 *  Process messages and send status if necessary.
	 *
	 *  If we're paused, we'll block for new messages.  If we're not
	 *  paused, we'll process anything we can peek but won't block
	 *  for more.  Detach (and re-attach) handling is all localized
	 *  to duk_debug_process_messages() too.
	 *
	 *  Debugger writes outside the message loop may cause debugger
	 *  detach1 phase to run, after which dbg_read_cb == NULL and
	 *  dbg_detaching != 0.  The message loop will finish the detach
	 *  by running detach2 phase, so enter the message loop also when
	 *  detaching.
	 */

	if (process_messages) {
		DUK_ASSERT(thr->heap->dbg_processing == 0);
		processed_messages = duk_debug_process_messages(thr, 0 /*no_block*/);
		DUK_ASSERT(thr->heap->dbg_processing == 0);
	}

	/* Continue checked execution if there are breakpoints or we're stepping.
	 * Also use checked execution if paused flag is active - it shouldn't be
	 * because the debug message loop shouldn't terminate if it was.  Step out
	 * is handled by callstack unwind and doesn't need checked execution.
	 * Note that debugger may have detached due to error or explicit request
	 * above, so we must recheck attach status.
	 */

	if (duk_debug_is_attached(thr->heap)) {
		DUK_ASSERT(act == thr->callstack_curr);
		DUK_ASSERT(act != NULL);
		if (act->flags & DUK_ACT_FLAG_BREAKPOINT_ACTIVE ||
		    (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_ONE_OPCODE) ||
		    ((thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_LINE_CHANGE) &&
		     thr->heap->dbg_pause_act == thr->callstack_curr) ||
		     DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap)) {
			*out_immediate = 1;
		}

		/* If we processed any debug messages breakpoints may have
		 * changed; restart execution to re-check active breakpoints.
		 */
		if (processed_messages) {
			DUK_D(DUK_DPRINT("processed debug messages, restart execution to recheck possibly changed breakpoints"));
			*out_interrupt_retval = DUK__INT_RESTART;
		} else {
			if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_ONE_OPCODE) {
				/* Set 'pause after one opcode' active only when we're
				 * actually just about to execute code.
				 */
				thr->heap->dbg_pause_flags |= DUK_PAUSE_FLAG_ONE_OPCODE_ACTIVE;
			}
		}
	} else {
		DUK_D(DUK_DPRINT("debugger became detached, resume normal execution"));
	}
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

DUK_LOCAL DUK_EXEC_NOINLINE_PERF DUK_COLD duk_small_uint_t duk__executor_interrupt(duk_hthread *thr) {
	duk_int_t ctr;
	duk_activation *act;
	duk_hcompfunc *fun;
	duk_bool_t immediate = 0;
	duk_small_uint_t retval;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(thr->callstack_top > 0);

#if defined(DUK_USE_DEBUG)
	thr->heap->inst_count_interrupt += thr->interrupt_init;
	DUK_DD(DUK_DDPRINT("execution interrupt, counter=%ld, init=%ld, "
	                   "instruction counts: executor=%ld, interrupt=%ld",
	                   (long) thr->interrupt_counter, (long) thr->interrupt_init,
	                   (long) thr->heap->inst_count_exec, (long) thr->heap->inst_count_interrupt));
#endif

	retval = DUK__INT_NOACTION;
	ctr = DUK_HTHREAD_INTCTR_DEFAULT;

	/*
	 *  Avoid nested calls.  Concretely this happens during debugging, e.g.
	 *  when we eval() an expression.
	 *
	 *  Also don't interrupt if we're currently doing debug processing
	 *  (which can be initiated outside the bytecode executor) as this
	 *  may cause the debugger to be called recursively.  Check required
	 *  for correct operation of throw intercept and other "exotic" halting
	 * scenarios.
	 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	if (DUK_HEAP_HAS_INTERRUPT_RUNNING(thr->heap) || thr->heap->dbg_processing) {
#else
	if (DUK_HEAP_HAS_INTERRUPT_RUNNING(thr->heap)) {
#endif
		DUK_DD(DUK_DDPRINT("nested executor interrupt, ignoring"));

		/* Set a high interrupt counter; the original executor
		 * interrupt invocation will rewrite before exiting.
		 */
		thr->interrupt_init = ctr;
		thr->interrupt_counter = ctr - 1;
		return DUK__INT_NOACTION;
	}
	DUK_HEAP_SET_INTERRUPT_RUNNING(thr->heap);

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);

	fun = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC((duk_hobject *) fun));

	DUK_UNREF(fun);

#if defined(DUK_USE_EXEC_TIMEOUT_CHECK)
	/*
	 *  Execution timeout check
	 */

	if (DUK_USE_EXEC_TIMEOUT_CHECK(thr->heap->heap_udata)) {
		/* Keep throwing an error whenever we get here.  The unusual values
		 * are set this way because no instruction is ever executed, we just
		 * throw an error until all try/catch/finally and other catchpoints
		 * have been exhausted.  Duktape/C code gets control at each protected
		 * call but whenever it enters back into Duktape the RangeError gets
		 * raised.  User exec timeout check must consistently indicate a timeout
		 * until we've fully bubbled out of Duktape.
		 */
		DUK_D(DUK_DPRINT("execution timeout, throwing a RangeError"));
		thr->interrupt_init = 0;
		thr->interrupt_counter = 0;
		DUK_HEAP_CLEAR_INTERRUPT_RUNNING(thr->heap);
		DUK_ERROR_RANGE(thr, "execution timeout");
		DUK_WO_NORETURN(return 0;);
	}
#endif  /* DUK_USE_EXEC_TIMEOUT_CHECK */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
	if (!thr->heap->dbg_processing &&
	    (thr->heap->dbg_read_cb != NULL || thr->heap->dbg_detaching)) {
		/* Avoid recursive re-entry; enter when we're attached or
		 * detaching (to finish off the pending detach).
		 */
		duk__interrupt_handle_debugger(thr, &immediate, &retval);
		DUK_ASSERT(act == thr->callstack_curr);
	}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

	/*
	 *  Update the interrupt counter
	 */

	if (immediate) {
		/* Cause an interrupt after executing one instruction. */
		ctr = 1;
	}

	/* The counter value is one less than the init value: init value should
	 * indicate how many instructions are executed before interrupt.  To
	 * execute 1 instruction (after interrupt handler return), counter must
	 * be 0.
	 */
	DUK_ASSERT(ctr >= 1);
	thr->interrupt_init = ctr;
	thr->interrupt_counter = ctr - 1;
	DUK_HEAP_CLEAR_INTERRUPT_RUNNING(thr->heap);

	return retval;
}
#endif  /* DUK_USE_INTERRUPT_COUNTER */

/*
 *  Debugger handling for executor restart
 *
 *  Check for breakpoints, stepping, etc, and figure out if we should execute
 *  in checked or normal mode.  Note that we can't do this when an activation
 *  is created, because breakpoint status (and stepping status) may change
 *  later, so we must recheck every time we're executing an activation.
 *  This primitive should be side effect free to avoid changes during check.
 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_LOCAL void duk__executor_recheck_debugger(duk_hthread *thr, duk_activation *act, duk_hcompfunc *fun) {
	duk_heap *heap;
	duk_tval *tv_tmp;
	duk_hstring *filename;
	duk_small_uint_t bp_idx;
	duk_breakpoint **bp_active;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(fun != NULL);

	heap = thr->heap;
	bp_active = heap->dbg_breakpoints_active;
	act->flags &= ~DUK_ACT_FLAG_BREAKPOINT_ACTIVE;

	tv_tmp = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, (duk_hobject *) fun, DUK_STRIDX_FILE_NAME);
	if (tv_tmp && DUK_TVAL_IS_STRING(tv_tmp)) {
		filename = DUK_TVAL_GET_STRING(tv_tmp);

		/* Figure out all active breakpoints.  A breakpoint is
		 * considered active if the current function's fileName
		 * matches the breakpoint's fileName, AND there is no
		 * inner function that has matching line numbers
		 * (otherwise a breakpoint would be triggered both
		 * inside and outside of the inner function which would
		 * be confusing).  Example:
		 *
		 *     function foo() {
		 *         print('foo');
		 *         function bar() {    <-.  breakpoints in these
		 *             print('bar');     |  lines should not affect
		 *         }                   <-'  foo() execution
		 *         bar();
		 *     }
		 *
		 * We need a few things that are only available when
		 * debugger support is enabled: (1) a line range for
		 * each function, and (2) access to the function
		 * template to access the inner functions (and their
		 * line ranges).
		 *
		 * It's important to have a narrow match for active
		 * breakpoints so that we don't enter checked execution
		 * when that's not necessary.  For instance, if we're
		 * running inside a certain function and there's
		 * breakpoint outside in (after the call site), we
		 * don't want to slow down execution of the function.
		 */

		for (bp_idx = 0; bp_idx < heap->dbg_breakpoint_count; bp_idx++) {
			duk_breakpoint *bp = heap->dbg_breakpoints + bp_idx;
			duk_hobject **funcs, **funcs_end;
			duk_hcompfunc *inner_fun;
			duk_bool_t bp_match;

			if (bp->filename == filename &&
			    bp->line >= fun->start_line && bp->line <= fun->end_line) {
				bp_match = 1;
				DUK_DD(DUK_DDPRINT("breakpoint filename and line match: "
				                   "%s:%ld vs. %s (line %ld vs. %ld-%ld)",
				                   DUK_HSTRING_GET_DATA(bp->filename),
				                   (long) bp->line,
				                   DUK_HSTRING_GET_DATA(filename),
				                   (long) bp->line,
				                   (long) fun->start_line,
				                   (long) fun->end_line));

				funcs = DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, fun);
				funcs_end = DUK_HCOMPFUNC_GET_FUNCS_END(thr->heap, fun);
				while (funcs != funcs_end) {
					inner_fun = (duk_hcompfunc *) *funcs;
					DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) inner_fun));
					if (bp->line >= inner_fun->start_line && bp->line <= inner_fun->end_line) {
						DUK_DD(DUK_DDPRINT("inner function masks ('captures') breakpoint"));
						bp_match = 0;
						break;
					}
					funcs++;
				}

				if (bp_match) {
					/* No need to check for size of bp_active list,
					 * it's always larger than maximum number of
					 * breakpoints.
					 */
					act->flags |= DUK_ACT_FLAG_BREAKPOINT_ACTIVE;
					*bp_active = heap->dbg_breakpoints + bp_idx;
					bp_active++;
				}
			}
		}
	}

	*bp_active = NULL;  /* terminate */

	DUK_DD(DUK_DDPRINT("ACTIVE BREAKPOINTS: %ld", (long) (bp_active - thr->heap->dbg_breakpoints_active)));

	/* Force pause if we were doing "step into" in another activation. */
	if ((thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_FUNC_ENTRY) &&
	    thr->heap->dbg_pause_act != thr->callstack_curr) {
		DUK_D(DUK_DPRINT("PAUSE TRIGGERED by function entry"));
		duk_debug_set_paused(thr->heap);
	}

	/* Force interrupt right away if we're paused or in "checked mode".
	 * Step out is handled by callstack unwind.
	 */
	if ((act->flags & DUK_ACT_FLAG_BREAKPOINT_ACTIVE) ||
	    DUK_HEAP_HAS_DEBUGGER_PAUSED(thr->heap) ||
	    ((thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_LINE_CHANGE) &&
	     thr->heap->dbg_pause_act == thr->callstack_curr)) {
		/* We'll need to interrupt early so recompute the init
		 * counter to reflect the number of bytecode instructions
		 * executed so that step counts for e.g. debugger rate
		 * limiting are accurate.
		 */
		DUK_ASSERT(thr->interrupt_counter <= thr->interrupt_init);
		thr->interrupt_init = thr->interrupt_init - thr->interrupt_counter;
		thr->interrupt_counter = 0;
	}
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

/*
 *  Opcode handlers for opcodes with a lot of code and which are relatively
 *  rare; NOINLINE to reduce amount of code in main bytecode dispatcher.
 */

DUK_LOCAL DUK_EXEC_NOINLINE_PERF void duk__handle_op_initset_initget(duk_hthread *thr, duk_uint_fast32_t ins) {
	duk_bool_t is_set = (DUK_DEC_OP(ins) == DUK_OP_INITSET);
	duk_uint_fast_t idx;
	duk_uint_t defprop_flags;

	/* A -> object register (acts as a source)
	 * BC -> BC+0 contains key, BC+1 closure (value)
	 */

	/* INITSET/INITGET are only used to initialize object literal keys.
	 * There may be a previous propery in ES2015 because duplicate property
	 * names are allowed.
	 */

	/* This could be made more optimal by accessing internals directly. */

	idx = (duk_uint_fast_t) DUK_DEC_BC(ins);
	duk_dup(thr, (duk_idx_t) (idx + 0));  /* key */
	duk_dup(thr, (duk_idx_t) (idx + 1));  /* getter/setter */
	if (is_set) {
	        defprop_flags = DUK_DEFPROP_HAVE_SETTER |
	                        DUK_DEFPROP_FORCE |
	                        DUK_DEFPROP_SET_ENUMERABLE |
	                        DUK_DEFPROP_SET_CONFIGURABLE;
	} else {
	        defprop_flags = DUK_DEFPROP_HAVE_GETTER |
	                        DUK_DEFPROP_FORCE |
	                        DUK_DEFPROP_SET_ENUMERABLE |
	                        DUK_DEFPROP_SET_CONFIGURABLE;
	}
	duk_def_prop(thr, (duk_idx_t) DUK_DEC_A(ins), defprop_flags);
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF void duk__handle_op_trycatch(duk_hthread *thr, duk_uint_fast32_t ins, duk_instr_t *curr_pc) {
	duk_activation *act;
	duk_catcher *cat;
	duk_tval *tv1;
	duk_small_uint_fast_t a;
	duk_small_uint_fast_t bc;

	/* A -> flags
	 * BC -> reg_catch; base register for two registers used both during
	 *       trycatch setup and when catch is triggered
	 *
	 *      If DUK_BC_TRYCATCH_FLAG_CATCH_BINDING set:
	 *          reg_catch + 0: catch binding variable name (string).
	 *          Automatic declarative environment is established for
	 *          the duration of the 'catch' clause.
	 *
	 *      If DUK_BC_TRYCATCH_FLAG_WITH_BINDING set:
	 *          reg_catch + 0: with 'target value', which is coerced to
	 *          an object and then used as a bindind object for an
	 *          environment record.  The binding is initialized here, for
	 *          the 'try' clause.
	 *
	 * Note that a TRYCATCH generated for a 'with' statement has no
	 * catch or finally parts.
	 */

	/* XXX: TRYCATCH handling should be reworked to avoid creating
	 * an explicit scope unless it is actually needed (e.g. function
	 * instances or eval is executed inside the catch block).  This
	 * rework is not trivial because the compiler doesn't have an
	 * intermediate representation.  When the rework is done, the
	 * opcode format can also be made more straightforward.
	 */

	/* XXX: side effect handling is quite awkward here */

	DUK_DDD(DUK_DDDPRINT("TRYCATCH: reg_catch=%ld, have_catch=%ld, "
	                     "have_finally=%ld, catch_binding=%ld, with_binding=%ld (flags=0x%02lx)",
	                     (long) DUK_DEC_BC(ins),
	                     (long) (DUK_DEC_A(ins) & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH ? 1 : 0),
	                     (long) (DUK_DEC_A(ins) & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY ? 1 : 0),
	                     (long) (DUK_DEC_A(ins) & DUK_BC_TRYCATCH_FLAG_CATCH_BINDING ? 1 : 0),
	                     (long) (DUK_DEC_A(ins) & DUK_BC_TRYCATCH_FLAG_WITH_BINDING ? 1 : 0),
	                     (unsigned long) DUK_DEC_A(ins)));

	a = DUK_DEC_A(ins);
	bc = DUK_DEC_BC(ins);

	/* Registers 'bc' and 'bc + 1' are written in longjmp handling
	 * and if their previous values (which are temporaries) become
	 * unreachable -and- have a finalizer, there'll be a function
	 * call during error handling which is not supported now (GH-287).
	 * Ensure that both 'bc' and 'bc + 1' have primitive values to
	 * guarantee no finalizer calls in error handling.  Scrubbing also
	 * ensures finalizers for the previous values run here rather than
	 * later.  Error handling related values are also written to 'bc'
	 * and 'bc + 1' but those values never become unreachable during
	 * error handling, so there's no side effect problem even if the
	 * error value has a finalizer.
	 */
	duk_dup(thr, (duk_idx_t) bc);  /* Stabilize value. */
	duk_to_undefined(thr, (duk_idx_t) bc);
	duk_to_undefined(thr, (duk_idx_t) (bc + 1));

	/* Allocate catcher and populate it.  Doesn't have to
	 * be fully atomic, but the catcher must be in a
	 * consistent state if side effects (such as finalizer
	 * calls) occur.
	 */

	cat = duk_hthread_catcher_alloc(thr);
	DUK_ASSERT(cat != NULL);

	cat->flags = DUK_CAT_TYPE_TCF;
	cat->h_varname = NULL;
	cat->pc_base = (duk_instr_t *) curr_pc;  /* pre-incremented, points to first jump slot */
	cat->idx_base = (duk_size_t) (thr->valstack_bottom - thr->valstack) + bc;

	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	cat->parent = act->cat;
	act->cat = cat;

	if (a & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH) {
		cat->flags |= DUK_CAT_FLAG_CATCH_ENABLED;
	}
	if (a & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY) {
		cat->flags |= DUK_CAT_FLAG_FINALLY_ENABLED;
	}
	if (a & DUK_BC_TRYCATCH_FLAG_CATCH_BINDING) {
		DUK_DDD(DUK_DDDPRINT("catch binding flag set to catcher"));
		cat->flags |= DUK_CAT_FLAG_CATCH_BINDING_ENABLED;
		tv1 = DUK_GET_TVAL_NEGIDX(thr, -1);
		DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));

		/* borrowed reference; although 'tv1' comes from a register,
		 * its value was loaded using LDCONST so the constant will
		 * also exist and be reachable.
		 */
		cat->h_varname = DUK_TVAL_GET_STRING(tv1);
	} else if (a & DUK_BC_TRYCATCH_FLAG_WITH_BINDING) {
		duk_hobjenv *env;
		duk_hobject *target;

		/* Delayed env initialization for activation (if needed). */
		DUK_ASSERT(thr->callstack_top >= 1);
		DUK_ASSERT(act == thr->callstack_curr);
		DUK_ASSERT(act != NULL);
		if (act->lex_env == NULL) {
			DUK_DDD(DUK_DDDPRINT("delayed environment initialization"));
			DUK_ASSERT(act->var_env == NULL);

			duk_js_init_activation_environment_records_delayed(thr, act);
			DUK_ASSERT(act == thr->callstack_curr);
			DUK_UNREF(act);  /* 'act' is no longer accessed, scanbuild fix */
		}
		DUK_ASSERT(act->lex_env != NULL);
		DUK_ASSERT(act->var_env != NULL);

		/* Coerce 'with' target. */
		target = duk_to_hobject(thr, -1);
		DUK_ASSERT(target != NULL);

		/* Create an object environment; it is not pushed
		 * so avoid side effects very carefully until it is
		 * referenced.
		 */
		env = duk_hobjenv_alloc(thr,
		                        DUK_HOBJECT_FLAG_EXTENSIBLE |
		                        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJENV));
		DUK_ASSERT(env != NULL);
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) env) == NULL);
		env->target = target;  /* always provideThis=true */
		DUK_HOBJECT_INCREF(thr, target);
		env->has_this = 1;
		DUK_HOBJENV_ASSERT_VALID(env);
		DUK_DDD(DUK_DDDPRINT("environment for with binding: %!iO", env));

		DUK_ASSERT(act == thr->callstack_curr);
		DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) env) == NULL);
		DUK_ASSERT(act->lex_env != NULL);
		DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) env, act->lex_env);
		act->lex_env = (duk_hobject *) env;  /* Now reachable. */
		DUK_HOBJECT_INCREF(thr, (duk_hobject *) env);
		/* Net refcount change to act->lex_env is 0: incref for env's
		 * prototype, decref for act->lex_env overwrite.
		 */

		/* Set catcher lex_env active (affects unwind)
		 * only when the whole setup is complete.
		 */
		cat = act->cat;  /* XXX: better to relookup? not mandatory because 'cat' is stable */
		cat->flags |= DUK_CAT_FLAG_LEXENV_ACTIVE;
	} else {
		;
	}

	DUK_DDD(DUK_DDDPRINT("TRYCATCH catcher: flags=0x%08lx, pc_base=%ld, "
	                     "idx_base=%ld, h_varname=%!O",
	                     (unsigned long) cat->flags,
	                     (long) cat->pc_base, (long) cat->idx_base, (duk_heaphdr *) cat->h_varname));

	duk_pop_unsafe(thr);
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF duk_instr_t *duk__handle_op_endtry(duk_hthread *thr, duk_uint_fast32_t ins) {
	duk_activation *act;
	duk_catcher *cat;
	duk_tval *tv1;
	duk_instr_t *pc_base;

	DUK_UNREF(ins);

	DUK_ASSERT(thr->callstack_top >= 1);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	cat = act->cat;
	DUK_ASSERT(cat != NULL);
	DUK_ASSERT(DUK_CAT_GET_TYPE(act->cat) == DUK_CAT_TYPE_TCF);

	DUK_DDD(DUK_DDDPRINT("ENDTRY: clearing catch active flag (regardless of whether it was set or not)"));
	DUK_CAT_CLEAR_CATCH_ENABLED(cat);

	pc_base = cat->pc_base;

	if (DUK_CAT_HAS_FINALLY_ENABLED(cat)) {
		DUK_DDD(DUK_DDDPRINT("ENDTRY: finally part is active, jump through 2nd jump slot with 'normal continuation'"));

		tv1 = thr->valstack + cat->idx_base;
		DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top);
		DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv1);  /* side effects */
		tv1 = NULL;

		tv1 = thr->valstack + cat->idx_base + 1;
		DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top);
		DUK_TVAL_SET_U32_UPDREF(thr, tv1, (duk_uint32_t) DUK_LJ_TYPE_NORMAL);  /* side effects */
		tv1 = NULL;

		DUK_CAT_CLEAR_FINALLY_ENABLED(cat);
	} else {
		DUK_DDD(DUK_DDDPRINT("ENDTRY: no finally part, dismantle catcher, jump through 2nd jump slot (to end of statement)"));

		duk_hthread_catcher_unwind_norz(thr, act);  /* lexenv may be set for 'with' binding */
		/* no need to unwind callstack */
	}

	return pc_base + 1;  /* new curr_pc value */
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF duk_instr_t *duk__handle_op_endcatch(duk_hthread *thr, duk_uint_fast32_t ins) {
	duk_activation *act;
	duk_catcher *cat;
	duk_tval *tv1;
	duk_instr_t *pc_base;

	DUK_UNREF(ins);

	DUK_ASSERT(thr->callstack_top >= 1);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	cat = act->cat;
	DUK_ASSERT(cat != NULL);
	DUK_ASSERT(!DUK_CAT_HAS_CATCH_ENABLED(cat));  /* cleared before entering catch part */

	if (DUK_CAT_HAS_LEXENV_ACTIVE(cat)) {
		duk_hobject *prev_env;

		/* 'with' binding has no catch clause, so can't be here unless a normal try-catch */
		DUK_ASSERT(DUK_CAT_HAS_CATCH_BINDING_ENABLED(cat));
		DUK_ASSERT(act->lex_env != NULL);

		DUK_DDD(DUK_DDDPRINT("ENDCATCH: popping catcher part lexical environment"));

		prev_env = act->lex_env;
		DUK_ASSERT(prev_env != NULL);
		act->lex_env = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, prev_env);
		DUK_CAT_CLEAR_LEXENV_ACTIVE(cat);
		DUK_HOBJECT_INCREF(thr, act->lex_env);
		DUK_HOBJECT_DECREF(thr, prev_env);  /* side effects */

		DUK_ASSERT(act == thr->callstack_curr);
		DUK_ASSERT(act != NULL);
	}

	pc_base = cat->pc_base;

	if (DUK_CAT_HAS_FINALLY_ENABLED(cat)) {
		DUK_DDD(DUK_DDDPRINT("ENDCATCH: finally part is active, jump through 2nd jump slot with 'normal continuation'"));

		tv1 = thr->valstack + cat->idx_base;
		DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top);
		DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv1);  /* side effects */
		tv1 = NULL;

		tv1 = thr->valstack + cat->idx_base + 1;
		DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top);
		DUK_TVAL_SET_U32_UPDREF(thr, tv1, (duk_uint32_t) DUK_LJ_TYPE_NORMAL);  /* side effects */
		tv1 = NULL;

		DUK_CAT_CLEAR_FINALLY_ENABLED(cat);
	} else {
		DUK_DDD(DUK_DDDPRINT("ENDCATCH: no finally part, dismantle catcher, jump through 2nd jump slot (to end of statement)"));

		duk_hthread_catcher_unwind_norz(thr, act);
		/* no need to unwind callstack */
	}

	return pc_base + 1;  /* new curr_pc value */
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF duk_small_uint_t duk__handle_op_endfin(duk_hthread *thr, duk_uint_fast32_t ins, duk_activation *entry_act) {
	duk_activation *act;
	duk_tval *tv1;
	duk_uint_t reg_catch;
	duk_small_uint_t cont_type;
	duk_small_uint_t ret_result;

	DUK_ASSERT(thr->ptr_curr_pc == NULL);
	DUK_ASSERT(thr->callstack_top >= 1);
	act = thr->callstack_curr;
	DUK_ASSERT(act != NULL);
	reg_catch = DUK_DEC_ABC(ins);

	/* CATCH flag may be enabled or disabled here; it may be enabled if
	 * the statement has a catch block but the try block does not throw
	 * an error.
	 */

	DUK_DDD(DUK_DDDPRINT("ENDFIN: completion value=%!T, type=%!T",
	                     (duk_tval *) (thr->valstack_bottom + reg_catch + 0),
	                     (duk_tval *) (thr->valstack_bottom + reg_catch + 1)));

	tv1 = thr->valstack_bottom + reg_catch + 1;  /* type */
	DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv1));
#if defined(DUK_USE_FASTINT)
	DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv1));
	cont_type = (duk_small_uint_t) DUK_TVAL_GET_FASTINT_U32(tv1);
#else
	cont_type = (duk_small_uint_t) DUK_TVAL_GET_NUMBER(tv1);
#endif

	tv1--;  /* value */

	switch (cont_type) {
	case DUK_LJ_TYPE_NORMAL: {
		DUK_DDD(DUK_DDDPRINT("ENDFIN: finally part finishing with 'normal' (non-abrupt) completion -> "
		                     "dismantle catcher, resume execution after ENDFIN"));

		duk_hthread_catcher_unwind_norz(thr, act);
		/* no need to unwind callstack */
		return 0;  /* restart execution */
	}
	case DUK_LJ_TYPE_RETURN: {
		DUK_DDD(DUK_DDDPRINT("ENDFIN: finally part finishing with 'return' complation -> dismantle "
		                     "catcher, handle return, lj.value1=%!T", tv1));

		/* Not necessary to unwind catch stack: return handling will
		 * do it.  The finally flag of 'cat' is no longer set.  The
		 * catch flag may be set, but it's not checked by return handling.
		 */

		duk_push_tval(thr, tv1);
		ret_result = duk__handle_return(thr, entry_act);
		if (ret_result == DUK__RETHAND_RESTART) {
			return 0;  /* restart execution */
		}
		DUK_ASSERT(ret_result == DUK__RETHAND_FINISHED);

		DUK_DDD(DUK_DDDPRINT("exiting executor after ENDFIN and RETURN (pseudo) longjmp type"));
		return 1;  /* exit executor */
	}
	case DUK_LJ_TYPE_BREAK:
	case DUK_LJ_TYPE_CONTINUE: {
		duk_uint_t label_id;
		duk_small_uint_t lj_type;

		/* Not necessary to unwind catch stack: break/continue
		 * handling will do it.  The finally flag of 'cat' is
		 * no longer set.  The catch flag may be set, but it's
		 * not checked by break/continue handling.
		 */

		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv1));
#if defined(DUK_USE_FASTINT)
		DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv1));
		label_id = (duk_small_uint_t) DUK_TVAL_GET_FASTINT_U32(tv1);
#else
		label_id = (duk_small_uint_t) DUK_TVAL_GET_NUMBER(tv1);
#endif
		lj_type = cont_type;
		duk__handle_break_or_continue(thr, label_id, lj_type);
		return 0;  /* restart execution */
	}
	default: {
		DUK_DDD(DUK_DDDPRINT("ENDFIN: finally part finishing with abrupt completion, lj_type=%ld -> "
		                     "dismantle catcher, re-throw error",
		                     (long) cont_type));

		duk_err_setup_ljstate1(thr, (duk_small_uint_t) cont_type, tv1);
		/* No debugger Throw notify check on purpose (rethrow). */

		DUK_ASSERT(thr->heap->lj.jmpbuf_ptr != NULL);  /* always in executor */
		duk_err_longjmp(thr);
		DUK_UNREACHABLE();
	}
	}

	DUK_UNREACHABLE();
	return 0;
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF void duk__handle_op_initenum(duk_hthread *thr, duk_uint_fast32_t ins) {
	duk_small_uint_t b;
	duk_small_uint_t c;

	/*
	 *  Enumeration semantics come from for-in statement, E5 Section 12.6.4.
	 *  If called with 'null' or 'undefined', this opcode returns 'null' as
	 *  the enumerator, which is special cased in NEXTENUM.  This simplifies
	 *  the compiler part
	 */

	/* B -> register for writing enumerator object
	 * C -> value to be enumerated (register)
	 */
	b = DUK_DEC_B(ins);
	c = DUK_DEC_C(ins);

	if (duk_is_null_or_undefined(thr, (duk_idx_t) c)) {
		duk_push_null(thr);
		duk_replace(thr, (duk_idx_t) b);
	} else {
		duk_dup(thr, (duk_idx_t) c);
		duk_to_object(thr, -1);
		duk_hobject_enumerator_create(thr, 0 /*enum_flags*/);  /* [ ... val ] --> [ ... enum ] */
		duk_replace(thr, (duk_idx_t) b);
	}
}

DUK_LOCAL DUK_EXEC_NOINLINE_PERF duk_small_uint_t duk__handle_op_nextenum(duk_hthread *thr, duk_uint_fast32_t ins) {
	duk_small_uint_t b;
	duk_small_uint_t c;
	duk_small_uint_t pc_skip = 0;

	/*
	 *  NEXTENUM checks whether the enumerator still has unenumerated
	 *  keys.  If so, the next key is loaded to the target register
	 *  and the next instruction is skipped.  Otherwise the next instruction
	 *  will be executed, jumping out of the enumeration loop.
	 */

	/* B -> target register for next key
	 * C -> enum register
	 */
	b = DUK_DEC_B(ins);
	c = DUK_DEC_C(ins);

	DUK_DDD(DUK_DDDPRINT("NEXTENUM: b->%!T, c->%!T",
	                     (duk_tval *) duk_get_tval(thr, (duk_idx_t) b),
	                     (duk_tval *) duk_get_tval(thr, (duk_idx_t) c)));

	if (duk_is_object(thr, (duk_idx_t) c)) {
		/* XXX: assert 'c' is an enumerator */
		duk_dup(thr, (duk_idx_t) c);
		if (duk_hobject_enumerator_next(thr, 0 /*get_value*/)) {
			/* [ ... enum ] -> [ ... next_key ] */
			DUK_DDD(DUK_DDDPRINT("enum active, next key is %!T, skip jump slot ",
			                     (duk_tval *) duk_get_tval(thr, -1)));
			pc_skip = 1;
		} else {
			/* [ ... enum ] -> [ ... ] */
			DUK_DDD(DUK_DDDPRINT("enum finished, execute jump slot"));
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));  /* valstack policy */
			thr->valstack_top++;
		}
		duk_replace(thr, (duk_idx_t) b);
	} else {
		/* 'null' enumerator case -> behave as with an empty enumerator */
		DUK_ASSERT(duk_is_null(thr, (duk_idx_t) c));
		DUK_DDD(DUK_DDDPRINT("enum is null, execute jump slot"));
	}

	return pc_skip;
}

/*
 *  Call handling helpers.
 */

DUK_LOCAL duk_bool_t duk__executor_handle_call(duk_hthread *thr, duk_idx_t idx, duk_idx_t nargs, duk_small_uint_t call_flags) {
	duk_bool_t rc;

	duk_set_top_unsafe(thr, (duk_idx_t) (idx + nargs + 2));   /* [ ... func this arg1 ... argN ] */

	/* Attempt an Ecma-to-Ecma call setup.  If the call
	 * target is (directly or indirectly) Reflect.construct(),
	 * the call may change into a constructor call on the fly.
	 */
	rc = (duk_bool_t) duk_handle_call_unprotected(thr, idx, call_flags);
	if (rc != 0) {
		/* Ecma-to-ecma call possible, may or may not
		 * be a tail call.  Avoid C recursion by
		 * reusing current executor instance.
		 */
		DUK_DDD(DUK_DDDPRINT("ecma-to-ecma call setup possible, restart execution"));
		/* curr_pc synced by duk_handle_call_unprotected() */
		DUK_ASSERT(thr->ptr_curr_pc == NULL);
		return rc;
	} else {
		/* Call was handled inline. */
	}
	DUK_ASSERT(thr->ptr_curr_pc != NULL);
	return rc;
}

/*
 *  ECMAScript bytecode executor.
 *
 *  Resume execution for the current thread from its current activation.
 *  Returns when execution would return from the entry level activation,
 *  leaving a single return value on top of the stack.  Function calls
 *  and thread resumptions are handled internally.  If an error occurs,
 *  a longjmp() with type DUK_LJ_TYPE_THROW is called on the entry level
 *  setjmp() jmpbuf.
 *
 *  ECMAScript function calls and coroutine resumptions are handled
 *  internally (by the outer executor function) without recursive C calls.
 *  Other function calls are handled using duk_handle_call(), increasing
 *  C recursion depth.
 *
 *  Abrupt completions (= long control tranfers) are handled either
 *  directly by reconfiguring relevant stacks and restarting execution,
 *  or via a longjmp.  Longjmp-free handling is preferable for performance
 *  (especially Emscripten performance), and is used for: break, continue,
 *  and return.
 *
 *  For more detailed notes, see doc/execution.rst.
 *
 *  Also see doc/code-issues.rst for discussion of setjmp(), longjmp(),
 *  and volatile.
 */

/* Presence of 'fun' is config based, there's a marginal performance
 * difference and the best option is architecture dependent.
 */
#if defined(DUK_USE_EXEC_FUN_LOCAL)
#define DUK__FUN()          fun
#else
#define DUK__FUN()          ((duk_hcompfunc *) DUK_ACT_GET_FUNC((thr)->callstack_curr))
#endif

/* Strict flag. */
#define DUK__STRICT()       ((duk_small_uint_t) DUK_HOBJECT_HAS_STRICT((duk_hobject *) DUK__FUN()))

/* Reg/const access macros: these are very footprint and performance sensitive
 * so modify with care.  Arguments are sometimes evaluated multiple times which
 * is not ideal.
 */
#define DUK__REG(x)         (*(thr->valstack_bottom + (x)))
#define DUK__REGP(x)        (thr->valstack_bottom + (x))
#define DUK__CONST(x)       (*(consts + (x)))
#define DUK__CONSTP(x)      (consts + (x))

/* Reg/const access macros which take the 32-bit instruction and avoid an
 * explicit field decoding step by using shifts and masks.  These must be
 * kept in sync with duk_js_bytecode.h.  The shift/mask values are chosen
 * so that 'ins' can be shifted and masked and used as a -byte- offset
 * instead of a duk_tval offset which needs further shifting (which is an
 * issue on some, but not all, CPUs).
 */
#define DUK__RCBIT_B           DUK_BC_REGCONST_B
#define DUK__RCBIT_C           DUK_BC_REGCONST_C
#if defined(DUK_USE_EXEC_REGCONST_OPTIMIZE)
#if defined(DUK_USE_PACKED_TVAL)
#define DUK__TVAL_SHIFT        3  /* sizeof(duk_tval) == 8 */
#else
#define DUK__TVAL_SHIFT        4  /* sizeof(duk_tval) == 16; not always the case so also asserted for */
#endif
#define DUK__SHIFT_A           (DUK_BC_SHIFT_A - DUK__TVAL_SHIFT)
#define DUK__SHIFT_B           (DUK_BC_SHIFT_B - DUK__TVAL_SHIFT)
#define DUK__SHIFT_C           (DUK_BC_SHIFT_C - DUK__TVAL_SHIFT)
#define DUK__SHIFT_BC          (DUK_BC_SHIFT_BC - DUK__TVAL_SHIFT)
#define DUK__MASK_A            (DUK_BC_UNSHIFTED_MASK_A << DUK__TVAL_SHIFT)
#define DUK__MASK_B            (DUK_BC_UNSHIFTED_MASK_B << DUK__TVAL_SHIFT)
#define DUK__MASK_C            (DUK_BC_UNSHIFTED_MASK_C << DUK__TVAL_SHIFT)
#define DUK__MASK_BC           (DUK_BC_UNSHIFTED_MASK_BC << DUK__TVAL_SHIFT)
#define DUK__BYTEOFF_A(ins)    (((ins) >> DUK__SHIFT_A) & DUK__MASK_A)
#define DUK__BYTEOFF_B(ins)    (((ins) >> DUK__SHIFT_B) & DUK__MASK_B)
#define DUK__BYTEOFF_C(ins)    (((ins) >> DUK__SHIFT_C) & DUK__MASK_C)
#define DUK__BYTEOFF_BC(ins)   (((ins) >> DUK__SHIFT_BC) & DUK__MASK_BC)

#define DUK__REGP_A(ins)       ((duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_bottom + DUK__BYTEOFF_A((ins))))
#define DUK__REGP_B(ins)       ((duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_bottom + DUK__BYTEOFF_B((ins))))
#define DUK__REGP_C(ins)       ((duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_bottom + DUK__BYTEOFF_C((ins))))
#define DUK__REGP_BC(ins)      ((duk_tval *) (void *) ((duk_uint8_t *) thr->valstack_bottom + DUK__BYTEOFF_BC((ins))))
#define DUK__CONSTP_A(ins)     ((duk_tval *) (void *) ((duk_uint8_t *) consts + DUK__BYTEOFF_A((ins))))
#define DUK__CONSTP_B(ins)     ((duk_tval *) (void *) ((duk_uint8_t *) consts + DUK__BYTEOFF_B((ins))))
#define DUK__CONSTP_C(ins)     ((duk_tval *) (void *) ((duk_uint8_t *) consts + DUK__BYTEOFF_C((ins))))
#define DUK__CONSTP_BC(ins)    ((duk_tval *) (void *) ((duk_uint8_t *) consts + DUK__BYTEOFF_BC((ins))))
#define DUK__REGCONSTP_B(ins)  ((duk_tval *) (void *) ((duk_uint8_t *) (((ins) & DUK__RCBIT_B) ? consts : thr->valstack_bottom) + DUK__BYTEOFF_B((ins))))
#define DUK__REGCONSTP_C(ins)  ((duk_tval *) (void *) ((duk_uint8_t *) (((ins) & DUK__RCBIT_C) ? consts : thr->valstack_bottom) + DUK__BYTEOFF_C((ins))))
#else  /* DUK_USE_EXEC_REGCONST_OPTIMIZE */
/* Safe alternatives, no assumption about duk_tval size. */
#define DUK__REGP_A(ins)       DUK__REGP(DUK_DEC_A((ins)))
#define DUK__REGP_B(ins)       DUK__REGP(DUK_DEC_B((ins)))
#define DUK__REGP_C(ins)       DUK__REGP(DUK_DEC_C((ins)))
#define DUK__REGP_BC(ins)      DUK__REGP(DUK_DEC_BC((ins)))
#define DUK__CONSTP_A(ins)     DUK__CONSTP(DUK_DEC_A((ins)))
#define DUK__CONSTP_B(ins)     DUK__CONSTP(DUK_DEC_B((ins)))
#define DUK__CONSTP_C(ins)     DUK__CONSTP(DUK_DEC_C((ins)))
#define DUK__CONSTP_BC(ins)    DUK__CONSTP(DUK_DEC_BC((ins)))
#define DUK__REGCONSTP_B(ins)  ((((ins) & DUK__RCBIT_B) ? consts : thr->valstack_bottom) + DUK_DEC_B((ins)))
#define DUK__REGCONSTP_C(ins)  ((((ins) & DUK__RCBIT_C) ? consts : thr->valstack_bottom) + DUK_DEC_C((ins)))
#endif  /* DUK_USE_EXEC_REGCONST_OPTIMIZE */

#if defined(DUK_USE_VERBOSE_EXECUTOR_ERRORS)
#define DUK__INTERNAL_ERROR(msg)  do { \
		DUK_ERROR_ERROR(thr, (msg)); \
		DUK_WO_NORETURN(return;); \
	} while (0)
#else
#define DUK__INTERNAL_ERROR(msg)  do { \
		goto internal_error; \
	} while (0)
#endif

#define DUK__SYNC_CURR_PC()  do { \
		duk_activation *duk__act; \
		duk__act = thr->callstack_curr; \
		duk__act->curr_pc = curr_pc; \
	} while (0)
#define DUK__SYNC_AND_NULL_CURR_PC()  do { \
		duk_activation *duk__act; \
		duk__act = thr->callstack_curr; \
		duk__act->curr_pc = curr_pc; \
		thr->ptr_curr_pc = NULL; \
	} while (0)

#if defined(DUK_USE_EXEC_PREFER_SIZE)
#define DUK__LOOKUP_INDIRECT(idx) do { \
		(idx) = (duk_uint_fast_t) duk_get_uint(thr, (duk_idx_t) (idx)); \
	} while (0)
#elif defined(DUK_USE_FASTINT)
#define DUK__LOOKUP_INDIRECT(idx) do { \
		duk_tval *tv_ind; \
		tv_ind = DUK__REGP((idx)); \
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_ind)); \
		DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv_ind));  /* compiler guarantees */ \
		(idx) = (duk_uint_fast_t) DUK_TVAL_GET_FASTINT_U32(tv_ind); \
	} while (0)
#else
#define DUK__LOOKUP_INDIRECT(idx) do { \
		duk_tval *tv_ind; \
		tv_ind = DUK__REGP(idx); \
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_ind)); \
		idx = (duk_uint_fast_t) DUK_TVAL_GET_NUMBER(tv_ind); \
	} while (0)
#endif

DUK_LOCAL void duk__handle_executor_error(duk_heap *heap,
                                          duk_activation *entry_act,
                                          duk_int_t entry_call_recursion_depth,
                                          duk_jmpbuf *entry_jmpbuf_ptr,
                                          volatile duk_bool_t *out_delayed_catch_setup) {
	duk_small_uint_t lj_ret;

	/* Longjmp callers are required to sync-and-null thr->ptr_curr_pc
	 * before longjmp.
	 */
	DUK_ASSERT(heap->curr_thread != NULL);
	DUK_ASSERT(heap->curr_thread->ptr_curr_pc == NULL);

	/* XXX: signalling the need to shrink check (only if unwound) */

	/* Must be restored here to handle e.g. yields properly. */
	heap->call_recursion_depth = entry_call_recursion_depth;

	/* Switch to caller's setjmp() catcher so that if an error occurs
	 * during error handling, it is always propagated outwards instead
	 * of causing an infinite loop in our own handler.
	 */
	heap->lj.jmpbuf_ptr = (duk_jmpbuf *) entry_jmpbuf_ptr;

	lj_ret = duk__handle_longjmp(heap->curr_thread, entry_act, out_delayed_catch_setup);

	/* Error handling complete, remove side effect protections.
	 */
#if defined(DUK_USE_ASSERTIONS)
	DUK_ASSERT(heap->error_not_allowed == 1);
	heap->error_not_allowed = 0;
#endif
	DUK_ASSERT(heap->pf_prevent_count > 0);
	heap->pf_prevent_count--;
	DUK_DD(DUK_DDPRINT("executor error handled, pf_prevent_count updated to %ld", (long) heap->pf_prevent_count));

	if (lj_ret == DUK__LONGJMP_RESTART) {
		/* Restart bytecode execution, possibly with a changed thread. */
		DUK_REFZERO_CHECK_SLOW(heap->curr_thread);
	} else {
		/* If an error is propagated, don't run refzero checks here.
		 * The next catcher will deal with that.  Pf_prevent_count
		 * will be re-bumped by the longjmp.
		 */

		DUK_ASSERT(lj_ret == DUK__LONGJMP_RETHROW);  /* Rethrow error to calling state. */
		DUK_ASSERT(heap->lj.jmpbuf_ptr == entry_jmpbuf_ptr);  /* Longjmp handling has restored jmpbuf_ptr. */

		/* Thread may have changed, e.g. YIELD converted to THROW. */
		duk_err_longjmp(heap->curr_thread);
		DUK_UNREACHABLE();
	}
}

/* Outer executor with setjmp/longjmp handling. */
DUK_INTERNAL void duk_js_execute_bytecode(duk_hthread *exec_thr) {
	/* Entry level info. */
	duk_hthread *entry_thread;
	duk_activation *entry_act;
	duk_int_t entry_call_recursion_depth;
	duk_jmpbuf *entry_jmpbuf_ptr;
	duk_jmpbuf our_jmpbuf;
	duk_heap *heap;
	volatile duk_bool_t delayed_catch_setup = 0;

	DUK_ASSERT(exec_thr != NULL);
	DUK_ASSERT(exec_thr->heap != NULL);
	DUK_ASSERT(exec_thr->heap->curr_thread != NULL);
	DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR((duk_heaphdr *) exec_thr);
	DUK_ASSERT(exec_thr->callstack_top >= 1);  /* at least one activation, ours */
	DUK_ASSERT(exec_thr->callstack_curr != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(exec_thr->callstack_curr) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(exec_thr->callstack_curr)));

	DUK_GC_TORTURE(exec_thr->heap);

	entry_thread = exec_thr;
	heap = entry_thread->heap;
	entry_act = entry_thread->callstack_curr;
	DUK_ASSERT(entry_act != NULL);
	entry_call_recursion_depth = entry_thread->heap->call_recursion_depth;
	entry_jmpbuf_ptr = entry_thread->heap->lj.jmpbuf_ptr;

	/*
	 *  Note: we currently assume that the setjmp() catchpoint is
	 *  not re-entrant (longjmp() cannot be called more than once
	 *  for a single setjmp()).
	 *
	 *  See doc/code-issues.rst for notes on variable assignment
	 *  before and after setjmp().
	 */

	for (;;) {
		heap->lj.jmpbuf_ptr = &our_jmpbuf;
		DUK_ASSERT(heap->lj.jmpbuf_ptr != NULL);

#if defined(DUK_USE_CPP_EXCEPTIONS)
		try {
#else
		DUK_ASSERT(heap->lj.jmpbuf_ptr == &our_jmpbuf);
		if (DUK_SETJMP(our_jmpbuf.jb) == 0) {
#endif
			DUK_DDD(DUK_DDDPRINT("after setjmp, delayed catch setup: %ld\n", (long) delayed_catch_setup));

			if (DUK_UNLIKELY(delayed_catch_setup != 0)) {
				duk_hthread *thr = entry_thread->heap->curr_thread;

				delayed_catch_setup = 0;
				duk__handle_catch_part2(thr);
				DUK_ASSERT(delayed_catch_setup == 0);
				DUK_DDD(DUK_DDDPRINT("top after delayed catch setup: %ld", (long) duk_get_top(entry_thread)));
			}

			/* Execute bytecode until returned or longjmp(). */
			duk__js_execute_bytecode_inner(entry_thread, entry_act);

			/* Successful return: restore jmpbuf and return to caller. */
			heap->lj.jmpbuf_ptr = entry_jmpbuf_ptr;

			return;
#if defined(DUK_USE_CPP_EXCEPTIONS)
		} catch (duk_internal_exception &exc) {
#else
		} else {
#endif
#if defined(DUK_USE_CPP_EXCEPTIONS)
			DUK_UNREF(exc);
#endif
			DUK_DDD(DUK_DDDPRINT("longjmp caught by bytecode executor"));
			DUK_STATS_INC(exec_thr->heap, stats_exec_throw);

			duk__handle_executor_error(heap,
			                           entry_act,
			                           entry_call_recursion_depth,
			                           entry_jmpbuf_ptr,
						   &delayed_catch_setup);
		}
#if defined(DUK_USE_CPP_EXCEPTIONS)
		catch (duk_fatal_exception &exc) {
			DUK_D(DUK_DPRINT("rethrow duk_fatal_exception"));
			DUK_UNREF(exc);
			throw;
		} catch (std::exception &exc) {
			const char *what = exc.what();
			if (!what) {
				what = "unknown";
			}
			DUK_D(DUK_DPRINT("unexpected c++ std::exception (perhaps thrown by user code)"));
			DUK_STATS_INC(exec_thr->heap, stats_exec_throw);
			try {
				DUK_ASSERT(heap->curr_thread != NULL);
				DUK_ERROR_FMT1(heap->curr_thread, DUK_ERR_TYPE_ERROR, "caught invalid c++ std::exception '%s' (perhaps thrown by user code)", what);
				DUK_WO_NORETURN(return;);
			} catch (duk_internal_exception exc) {
				DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ std::exception"));
				DUK_UNREF(exc);
				duk__handle_executor_error(heap,
				                           entry_act,
				                           entry_call_recursion_depth,
				                           entry_jmpbuf_ptr,
							   &delayed_catch_setup);
			}
		} catch (...) {
			DUK_D(DUK_DPRINT("unexpected c++ exception (perhaps thrown by user code)"));
			DUK_STATS_INC(exec_thr->heap, stats_exec_throw);
			try {
				DUK_ASSERT(heap->curr_thread != NULL);
				DUK_ERROR_TYPE(heap->curr_thread, "caught invalid c++ exception (perhaps thrown by user code)");
				DUK_WO_NORETURN(return;);
			} catch (duk_internal_exception exc) {
				DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ exception"));
				DUK_UNREF(exc);
				duk__handle_executor_error(heap,
				                           entry_act,
				                           entry_call_recursion_depth,
				                           entry_jmpbuf_ptr,
							   &delayed_catch_setup);
			}
		}
#endif
	}

	DUK_WO_NORETURN(return;);
}

/* Inner executor, performance critical. */
DUK_LOCAL DUK_NOINLINE DUK_HOT void duk__js_execute_bytecode_inner(duk_hthread *entry_thread, duk_activation *entry_act) {
	/* Current PC, accessed by other functions through thr->ptr_to_curr_pc.
	 * Critical for performance.  It would be safest to make this volatile,
	 * but that eliminates performance benefits; aliasing guarantees
	 * should be enough though.
	 */
	duk_instr_t *curr_pc;         /* bytecode has a stable pointer */

	/* Hot variables for interpretation.  Critical for performance,
	 * but must add sparingly to minimize register shuffling.
	 */
	duk_hthread *thr;             /* stable */
	duk_tval *consts;             /* stable */
	duk_uint_fast32_t ins;
	/* 'funcs' is quite rarely used, so no local for it */
#if defined(DUK_USE_EXEC_FUN_LOCAL)
	duk_hcompfunc *fun;
#else
	/* 'fun' is quite rarely used, so no local for it */
#endif

#if defined(DUK_USE_INTERRUPT_COUNTER)
	duk_int_t int_ctr;
#endif

#if defined(DUK_USE_ASSERTIONS)
	duk_size_t valstack_top_base;    /* valstack top, should match before interpreting each op (no leftovers) */
#endif

	/* Optimized reg/const access macros assume sizeof(duk_tval) to be
	 * either 8 or 16.  Heap allocation checks this even without asserts
	 * enabled now because it can't be autodetected in duk_config.h.
	 */
#if 1
#if defined(DUK_USE_PACKED_TVAL)
	DUK_ASSERT(sizeof(duk_tval) == 8);
#else
	DUK_ASSERT(sizeof(duk_tval) == 16);
#endif
#endif

	DUK_GC_TORTURE(entry_thread->heap);

	/*
	 *  Restart execution by reloading thread state.
	 *
	 *  Note that 'thr' and any thread configuration may have changed,
	 *  so all local variables are suspect and we need to reinitialize.
	 *
	 *  The number of local variables should be kept to a minimum: if
	 *  the variables are spilled, they will need to be loaded from
	 *  memory anyway.
	 *
	 *  Any 'goto restart_execution;' code path in opcode dispatch must
	 *  ensure 'curr_pc' is synced back to act->curr_pc before the goto
	 *  takes place.
	 *
	 *  The interpreter must be very careful with memory pointers, as
	 *  many pointers are not guaranteed to be 'stable' and may be
	 *  reallocated and relocated on-the-fly quite easily (e.g. by a
	 *  memory allocation or a property access).
	 *
	 *  The following are assumed to have stable pointers:
	 *    - the current thread
	 *    - the current function
	 *    - the bytecode, constant table, inner function table of the
	 *      current function (as they are a part of the function allocation)
	 *
	 *  The following are assumed to have semi-stable pointers:
	 *    - the current activation entry: stable as long as callstack
	 *      is not changed (reallocated by growing or shrinking), or
	 *      by any garbage collection invocation (through finalizers)
	 *    - Note in particular that ANY DECREF can invalidate the
	 *      activation pointer, so for the most part a fresh lookup
	 *      is required
	 *
	 *  The following are not assumed to have stable pointers at all:
	 *    - the value stack (registers) of the current thread
	 *
	 *  See execution.rst for discussion.
	 */

 restart_execution:

	/* Lookup current thread; use the stable 'entry_thread' for this to
	 * avoid clobber warnings.  Any valid, reachable 'thr' value would be
	 * fine for this, so using 'entry_thread' is just to silence warnings.
	 */
	thr = entry_thread->heap->curr_thread;
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->callstack_top >= 1);
	DUK_ASSERT(thr->callstack_curr != NULL);
	DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));

	DUK_GC_TORTURE(thr->heap);

	thr->ptr_curr_pc = &curr_pc;

	/* Relookup and initialize dispatch loop variables.  Debugger check. */
	{
		duk_activation *act;
#if !defined(DUK_USE_EXEC_FUN_LOCAL)
		duk_hcompfunc *fun;
#endif

		/* Assume interrupt init/counter are properly initialized here. */
		/* Assume that thr->valstack_bottom has been set-up before getting here. */

		act = thr->callstack_curr;
		DUK_ASSERT(act != NULL);
		fun = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);
		DUK_ASSERT(fun != NULL);
		DUK_ASSERT(thr->valstack_top - thr->valstack_bottom == fun->nregs);
		consts = DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, fun);
		DUK_ASSERT(consts != NULL);

#if defined(DUK_USE_DEBUGGER_SUPPORT)
		if (DUK_UNLIKELY(duk_debug_is_attached(thr->heap) && !thr->heap->dbg_processing)) {
			duk__executor_recheck_debugger(thr, act, fun);
			DUK_ASSERT(act == thr->callstack_curr);
			DUK_ASSERT(act != NULL);
		}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */

#if defined(DUK_USE_ASSERTIONS)
		valstack_top_base = (duk_size_t) (thr->valstack_top - thr->valstack);
#endif

		/* Set up curr_pc for opcode dispatch. */
		curr_pc = act->curr_pc;
	}

	DUK_DD(DUK_DDPRINT("restarting execution, thr %p, act idx %ld, fun %p,"
	                   "consts %p, funcs %p, lev %ld, regbot %ld, regtop %ld, "
	                   "preventcount=%ld",
	                   (void *) thr,
	                   (long) (thr->callstack_top - 1),
	                   (void *) DUK__FUN(),
	                   (void *) DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, DUK__FUN()),
	                   (void *) DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, DUK__FUN()),
	                   (long) (thr->callstack_top - 1),
	                   (long) (thr->valstack_bottom - thr->valstack),
	                   (long) (thr->valstack_top - thr->valstack),
	                   (long) thr->callstack_preventcount));

	/* Dispatch loop. */

	for (;;) {
		duk_uint8_t op;

		DUK_ASSERT(thr->callstack_top >= 1);
		DUK_ASSERT(thr->valstack_top - thr->valstack_bottom == DUK__FUN()->nregs);
		DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack) == valstack_top_base);

		/* Executor interrupt counter check, used to implement breakpoints,
		 * debugging interface, execution timeouts, etc.  The counter is heap
		 * specific but is maintained in the current thread to make the check
		 * as fast as possible.  The counter is copied back to the heap struct
		 * whenever a thread switch occurs by the DUK_HEAP_SWITCH_THREAD() macro.
		 */
#if defined(DUK_USE_INTERRUPT_COUNTER)
		int_ctr = thr->interrupt_counter;
		if (DUK_LIKELY(int_ctr > 0)) {
			thr->interrupt_counter = int_ctr - 1;
		} else {
			/* Trigger at zero or below */
			duk_small_uint_t exec_int_ret;

			DUK_STATS_INC(thr->heap, stats_exec_interrupt);

			/* Write curr_pc back for the debugger. */
			{
				duk_activation *act;
				DUK_ASSERT(thr->callstack_top > 0);
				act = thr->callstack_curr;
				DUK_ASSERT(act != NULL);
				act->curr_pc = (duk_instr_t *) curr_pc;
			}

			/* Forced restart caused by a function return; must recheck
			 * debugger breakpoints before checking line transitions,
			 * see GH-303.  Restart and then handle interrupt_counter
			 * zero again.
			 */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
			if (thr->heap->dbg_force_restart) {
				DUK_DD(DUK_DDPRINT("dbg_force_restart flag forced restart execution"));  /* GH-303 */
				thr->heap->dbg_force_restart = 0;
				goto restart_execution;
			}
#endif

			exec_int_ret = duk__executor_interrupt(thr);
			if (exec_int_ret == DUK__INT_RESTART) {
				/* curr_pc synced back above */
				goto restart_execution;
			}
		}
#endif  /* DUK_USE_INTERRUPT_COUNTER */
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
		/* For cross-checking during development: ensure dispatch count
		 * matches cumulative interrupt counter init value sums.
		 */
		thr->heap->inst_count_exec++;
#endif

#if defined(DUK_USE_ASSERTIONS) || defined(DUK_USE_DEBUG)
		{
			duk_activation *act;
			act = thr->callstack_curr;
			DUK_ASSERT(curr_pc >= DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, DUK__FUN()));
			DUK_ASSERT(curr_pc < DUK_HCOMPFUNC_GET_CODE_END(thr->heap, DUK__FUN()));
			DUK_UNREF(act);  /* if debugging disabled */

			DUK_DDD(DUK_DDDPRINT("executing bytecode: pc=%ld, ins=0x%08lx, op=%ld, valstack_top=%ld/%ld, nregs=%ld  -->  %!I",
			                     (long) (curr_pc - DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, DUK__FUN())),
			                     (unsigned long) *curr_pc,
			                     (long) DUK_DEC_OP(*curr_pc),
			                     (long) (thr->valstack_top - thr->valstack),
			                     (long) (thr->valstack_end - thr->valstack),
			                     (long) (DUK__FUN() ? DUK__FUN()->nregs : -1),
			                     (duk_instr_t) *curr_pc));
		}
#endif

#if defined(DUK_USE_ASSERTIONS)
		/* Quite heavy assert: check valstack policy.  Improper
		 * shuffle instructions can write beyond valstack_top/end
		 * so this check catches them in the act.
		 */
		{
			duk_tval *tv;
			tv = thr->valstack_top;
			while (tv != thr->valstack_end) {
				DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(tv));
				tv++;
			}
		}
#endif

		ins = *curr_pc++;
		DUK_STATS_INC(thr->heap, stats_exec_opcodes);

		/* Typing: use duk_small_(u)int_fast_t when decoding small
		 * opcode fields (op, A, B, C, BC) which fit into 16 bits
		 * and duk_(u)int_fast_t when decoding larger fields (e.g.
		 * ABC).  Use unsigned variant by default, signed when the
		 * value is used in signed arithmetic.  Using variable names
		 * such as 'a', 'b', 'c', 'bc', etc makes it easier to spot
		 * typing mismatches.
		 */

		/* Switch based on opcode.  Cast to 8-bit unsigned value and
		 * use a fully populated case clauses so that the compiler
		 * will (at least usually) omit a bounds check.
		 */
		op = (duk_uint8_t) DUK_DEC_OP(ins);
		switch (op) {

		/* Some useful macros.  These access inner executor variables
		 * directly so they only apply within the executor.
		 */
#if defined(DUK_USE_EXEC_PREFER_SIZE)
#define DUK__REPLACE_TOP_A_BREAK() { goto replace_top_a; }
#define DUK__REPLACE_TOP_BC_BREAK() { goto replace_top_bc; }
#define DUK__REPLACE_BOOL_A_BREAK(bval) { \
		duk_bool_t duk__bval; \
		duk__bval = (bval); \
		DUK_ASSERT(duk__bval == 0 || duk__bval == 1); \
		duk_push_boolean(thr, duk__bval); \
		DUK__REPLACE_TOP_A_BREAK(); \
	}
#else
#define DUK__REPLACE_TOP_A_BREAK() { DUK__REPLACE_TO_TVPTR(thr, DUK__REGP_A(ins)); break; }
#define DUK__REPLACE_TOP_BC_BREAK() { DUK__REPLACE_TO_TVPTR(thr, DUK__REGP_BC(ins)); break; }
#define DUK__REPLACE_BOOL_A_BREAK(bval) { \
		duk_bool_t duk__bval; \
		duk_tval *duk__tvdst; \
		duk__bval = (bval); \
		DUK_ASSERT(duk__bval == 0 || duk__bval == 1); \
		duk__tvdst = DUK__REGP_A(ins); \
		DUK_TVAL_SET_BOOLEAN_UPDREF(thr, duk__tvdst, duk__bval); \
		break; \
	}
#endif

		/* XXX: 12 + 12 bit variant might make sense too, for both reg and
		 * const loads.
		 */

		/* For LDREG, STREG, LDCONST footprint optimized variants would just
		 * duk_dup() + duk_replace(), but because they're used quite a lot
		 * they're currently intentionally not size optimized.
		 */
		case DUK_OP_LDREG: {
			duk_tval *tv1, *tv2;

			tv1 = DUK__REGP_A(ins);
			tv2 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_TVAL_UPDREF_FAST(thr, tv1, tv2);  /* side effects */
			break;
		}

		case DUK_OP_STREG: {
			duk_tval *tv1, *tv2;

			tv1 = DUK__REGP_A(ins);
			tv2 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_TVAL_UPDREF_FAST(thr, tv2, tv1);  /* side effects */
			break;
		}

		case DUK_OP_LDCONST: {
			duk_tval *tv1, *tv2;

			tv1 = DUK__REGP_A(ins);
			tv2 = DUK__CONSTP_BC(ins);
			DUK_TVAL_SET_TVAL_UPDREF_FAST(thr, tv1, tv2);  /* side effects */
			break;
		}

		/* LDINT and LDINTX are intended to load an arbitrary signed
		 * 32-bit value.  Only an LDINT+LDINTX sequence is supported.
		 * This also guarantees all values remain fastints.
		 */
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_LDINT: {
			duk_int32_t val;

			val = (duk_int32_t) DUK_DEC_BC(ins) - (duk_int32_t) DUK_BC_LDINT_BIAS;
			duk_push_int(thr, val);
			DUK__REPLACE_TOP_A_BREAK();
		}
		case DUK_OP_LDINTX: {
			duk_int32_t val;

			val = (duk_int32_t) duk_get_int(thr, DUK_DEC_A(ins));
			val = (val << DUK_BC_LDINTX_SHIFT) + (duk_int32_t) DUK_DEC_BC(ins);  /* no bias */
			duk_push_int(thr, val);
			DUK__REPLACE_TOP_A_BREAK();
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_LDINT: {
			duk_tval *tv1;
			duk_int32_t val;

			val = (duk_int32_t) DUK_DEC_BC(ins) - (duk_int32_t) DUK_BC_LDINT_BIAS;
			tv1 = DUK__REGP_A(ins);
			DUK_TVAL_SET_I32_UPDREF(thr, tv1, val);  /* side effects */
			break;
		}
		case DUK_OP_LDINTX: {
			duk_tval *tv1;
			duk_int32_t val;

			tv1 = DUK__REGP_A(ins);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv1));
#if defined(DUK_USE_FASTINT)
			DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv1));
			val = DUK_TVAL_GET_FASTINT_I32(tv1);
#else
			/* XXX: fast double-to-int conversion, we know number is integer in [-0x80000000,0xffffffff]. */
			val = (duk_int32_t) DUK_TVAL_GET_NUMBER(tv1);
#endif
			val = (duk_int32_t) ((duk_uint32_t) val << DUK_BC_LDINTX_SHIFT) + (duk_int32_t) DUK_DEC_BC(ins);  /* no bias */
			DUK_TVAL_SET_I32_UPDREF(thr, tv1, val);  /* side effects */
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_LDTHIS: {
			duk_push_this(thr);
			DUK__REPLACE_TOP_BC_BREAK();
		}
		case DUK_OP_LDUNDEF: {
			duk_to_undefined(thr, (duk_idx_t) DUK_DEC_BC(ins));
			break;
		}
		case DUK_OP_LDNULL: {
			duk_to_null(thr, (duk_idx_t) DUK_DEC_BC(ins));
			break;
		}
		case DUK_OP_LDTRUE: {
			duk_push_true(thr);
			DUK__REPLACE_TOP_BC_BREAK();
		}
		case DUK_OP_LDFALSE: {
			duk_push_false(thr);
			DUK__REPLACE_TOP_BC_BREAK();
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_LDTHIS: {
			/* Note: 'this' may be bound to any value, not just an object */
			duk_tval *tv1, *tv2;

			tv1 = DUK__REGP_BC(ins);
			tv2 = thr->valstack_bottom - 1;  /* 'this binding' is just under bottom */
			DUK_ASSERT(tv2 >= thr->valstack);
			DUK_TVAL_SET_TVAL_UPDREF_FAST(thr, tv1, tv2);  /* side effects */
			break;
		}
		case DUK_OP_LDUNDEF: {
			duk_tval *tv1;

			tv1 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv1);  /* side effects */
			break;
		}
		case DUK_OP_LDNULL: {
			duk_tval *tv1;

			tv1 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_NULL_UPDREF(thr, tv1);  /* side effects */
			break;
		}
		case DUK_OP_LDTRUE: {
			duk_tval *tv1;

			tv1 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_BOOLEAN_UPDREF(thr, tv1, 1);  /* side effects */
			break;
		}
		case DUK_OP_LDFALSE: {
			duk_tval *tv1;

			tv1 = DUK__REGP_BC(ins);
			DUK_TVAL_SET_BOOLEAN_UPDREF(thr, tv1, 0);  /* side effects */
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		case DUK_OP_BNOT: {
			duk__vm_bitwise_not(thr, DUK_DEC_BC(ins), DUK_DEC_A(ins));
			break;
		}

		case DUK_OP_LNOT: {
			duk__vm_logical_not(thr, DUK_DEC_BC(ins), DUK_DEC_A(ins));
			break;
		}

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_UNM:
		case DUK_OP_UNP: {
			duk__vm_arith_unary_op(thr, DUK_DEC_BC(ins), DUK_DEC_A(ins), op);
			break;
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_UNM: {
			duk__vm_arith_unary_op(thr, DUK_DEC_BC(ins), DUK_DEC_A(ins), DUK_OP_UNM);
			break;
		}
		case DUK_OP_UNP: {
			duk__vm_arith_unary_op(thr, DUK_DEC_BC(ins), DUK_DEC_A(ins), DUK_OP_UNP);
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_TYPEOF: {
			duk_small_uint_t stridx;

			stridx = duk_js_typeof_stridx(DUK__REGP_BC(ins));
			DUK_ASSERT_STRIDX_VALID(stridx);
			duk_push_hstring_stridx(thr, stridx);
			DUK__REPLACE_TOP_A_BREAK();
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_TYPEOF: {
			duk_tval *tv;
			duk_small_uint_t stridx;
			duk_hstring *h_str;

			tv = DUK__REGP_BC(ins);
			stridx = duk_js_typeof_stridx(tv);
			DUK_ASSERT_STRIDX_VALID(stridx);
			h_str = DUK_HTHREAD_GET_STRING(thr, stridx);
			tv = DUK__REGP_A(ins);
			DUK_TVAL_SET_STRING_UPDREF(thr, tv, h_str);
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		case DUK_OP_TYPEOFID: {
			duk_small_uint_t stridx;
#if !defined(DUK_USE_EXEC_PREFER_SIZE)
			duk_hstring *h_str;
#endif
			duk_activation *act;
			duk_hstring *name;
			duk_tval *tv;

			/* A -> target register
			 * BC -> constant index of identifier name
			 */

			tv = DUK__CONSTP_BC(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv));
			name = DUK_TVAL_GET_STRING(tv);
			tv = NULL;  /* lookup has side effects */
			act = thr->callstack_curr;
			if (duk_js_getvar_activation(thr, act, name, 0 /*throw*/)) {
				/* -> [... val this] */
				tv = DUK_GET_TVAL_NEGIDX(thr, -2);
				stridx = duk_js_typeof_stridx(tv);
				tv = NULL;  /* no longer needed */
				duk_pop_2_unsafe(thr);
			} else {
				/* unresolvable, no stack changes */
				stridx = DUK_STRIDX_LC_UNDEFINED;
			}
			DUK_ASSERT_STRIDX_VALID(stridx);
#if defined(DUK_USE_EXEC_PREFER_SIZE)
			duk_push_hstring_stridx(thr, stridx);
			DUK__REPLACE_TOP_A_BREAK();
#else  /* DUK_USE_EXEC_PREFER_SIZE */
			h_str = DUK_HTHREAD_GET_STRING(thr, stridx);
			tv = DUK__REGP_A(ins);
			DUK_TVAL_SET_STRING_UPDREF(thr, tv, h_str);
			break;
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
		}

		/* Equality: E5 Sections 11.9.1, 11.9.3 */

#define DUK__EQ_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_equals(thr, (barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#define DUK__NEQ_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_equals(thr, (barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		tmp ^= 1; \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#define DUK__SEQ_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_strict_equals((barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#define DUK__SNEQ_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_strict_equals((barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		tmp ^= 1; \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_EQ_RR:
		case DUK_OP_EQ_CR:
		case DUK_OP_EQ_RC:
		case DUK_OP_EQ_CC:
			DUK__EQ_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_NEQ_RR:
		case DUK_OP_NEQ_CR:
		case DUK_OP_NEQ_RC:
		case DUK_OP_NEQ_CC:
			DUK__NEQ_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_SEQ_RR:
		case DUK_OP_SEQ_CR:
		case DUK_OP_SEQ_RC:
		case DUK_OP_SEQ_CC:
			DUK__SEQ_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_SNEQ_RR:
		case DUK_OP_SNEQ_CR:
		case DUK_OP_SNEQ_RC:
		case DUK_OP_SNEQ_CC:
			DUK__SNEQ_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_EQ_RR:
			DUK__EQ_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_EQ_CR:
			DUK__EQ_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_EQ_RC:
			DUK__EQ_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_EQ_CC:
			DUK__EQ_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_NEQ_RR:
			DUK__NEQ_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_NEQ_CR:
			DUK__NEQ_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_NEQ_RC:
			DUK__NEQ_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_NEQ_CC:
			DUK__NEQ_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_SEQ_RR:
			DUK__SEQ_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_SEQ_CR:
			DUK__SEQ_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_SEQ_RC:
			DUK__SEQ_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_SEQ_CC:
			DUK__SEQ_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_SNEQ_RR:
			DUK__SNEQ_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_SNEQ_CR:
			DUK__SNEQ_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_SNEQ_RC:
			DUK__SNEQ_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_SNEQ_CC:
			DUK__SNEQ_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

#define DUK__COMPARE_BODY(arg1,arg2,flags) { \
		duk_bool_t tmp; \
		tmp = duk_js_compare_helper(thr, (arg1), (arg2), (flags)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#define DUK__GT_BODY(barg,carg) DUK__COMPARE_BODY((carg), (barg), 0)
#define DUK__GE_BODY(barg,carg) DUK__COMPARE_BODY((barg), (carg), DUK_COMPARE_FLAG_EVAL_LEFT_FIRST | DUK_COMPARE_FLAG_NEGATE)
#define DUK__LT_BODY(barg,carg) DUK__COMPARE_BODY((barg), (carg), DUK_COMPARE_FLAG_EVAL_LEFT_FIRST)
#define DUK__LE_BODY(barg,carg) DUK__COMPARE_BODY((carg), (barg), DUK_COMPARE_FLAG_NEGATE)
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_GT_RR:
		case DUK_OP_GT_CR:
		case DUK_OP_GT_RC:
		case DUK_OP_GT_CC:
			DUK__GT_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_GE_RR:
		case DUK_OP_GE_CR:
		case DUK_OP_GE_RC:
		case DUK_OP_GE_CC:
			DUK__GE_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_LT_RR:
		case DUK_OP_LT_CR:
		case DUK_OP_LT_RC:
		case DUK_OP_LT_CC:
			DUK__LT_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_LE_RR:
		case DUK_OP_LE_CR:
		case DUK_OP_LE_RC:
		case DUK_OP_LE_CC:
			DUK__LE_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_GT_RR:
			DUK__GT_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GT_CR:
			DUK__GT_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GT_RC:
			DUK__GT_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_GT_CC:
			DUK__GT_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_GE_RR:
			DUK__GE_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GE_CR:
			DUK__GE_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GE_RC:
			DUK__GE_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_GE_CC:
			DUK__GE_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_LT_RR:
			DUK__LT_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_LT_CR:
			DUK__LT_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_LT_RC:
			DUK__LT_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_LT_CC:
			DUK__LT_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_LE_RR:
			DUK__LE_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_LE_CR:
			DUK__LE_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_LE_RC:
			DUK__LE_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_LE_CC:
			DUK__LE_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		/* No size optimized variant at present for IF. */
		case DUK_OP_IFTRUE_R: {
			if (duk_js_toboolean(DUK__REGP_BC(ins)) != 0) {
				curr_pc++;
			}
			break;
		}
		case DUK_OP_IFTRUE_C: {
			if (duk_js_toboolean(DUK__CONSTP_BC(ins)) != 0) {
				curr_pc++;
			}
			break;
		}
		case DUK_OP_IFFALSE_R: {
			if (duk_js_toboolean(DUK__REGP_BC(ins)) == 0) {
				curr_pc++;
			}
			break;
		}
		case DUK_OP_IFFALSE_C: {
			if (duk_js_toboolean(DUK__CONSTP_BC(ins)) == 0) {
				curr_pc++;
			}
			break;
		}

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_ADD_RR:
		case DUK_OP_ADD_CR:
		case DUK_OP_ADD_RC:
		case DUK_OP_ADD_CC: {
			/* XXX: could leave value on stack top and goto replace_top_a; */
			duk__vm_arith_add(thr, DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins), DUK_DEC_A(ins));
			break;
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_ADD_RR: {
			duk__vm_arith_add(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins));
			break;
		}
		case DUK_OP_ADD_CR: {
			duk__vm_arith_add(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins));
			break;
		}
		case DUK_OP_ADD_RC: {
			duk__vm_arith_add(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins));
			break;
		}
		case DUK_OP_ADD_CC: {
			duk__vm_arith_add(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins));
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_SUB_RR:
		case DUK_OP_SUB_CR:
		case DUK_OP_SUB_RC:
		case DUK_OP_SUB_CC:
		case DUK_OP_MUL_RR:
		case DUK_OP_MUL_CR:
		case DUK_OP_MUL_RC:
		case DUK_OP_MUL_CC:
		case DUK_OP_DIV_RR:
		case DUK_OP_DIV_CR:
		case DUK_OP_DIV_RC:
		case DUK_OP_DIV_CC:
		case DUK_OP_MOD_RR:
		case DUK_OP_MOD_CR:
		case DUK_OP_MOD_RC:
		case DUK_OP_MOD_CC:
#if defined(DUK_USE_ES7_EXP_OPERATOR)
		case DUK_OP_EXP_RR:
		case DUK_OP_EXP_CR:
		case DUK_OP_EXP_RC:
		case DUK_OP_EXP_CC:
#endif  /* DUK_USE_ES7_EXP_OPERATOR */
		{
			/* XXX: could leave value on stack top and goto replace_top_a; */
			duk__vm_arith_binary_op(thr, DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins), DUK_DEC_A(ins), op);
			break;
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_SUB_RR: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_SUB);
			break;
		}
		case DUK_OP_SUB_CR: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_SUB);
			break;
		}
		case DUK_OP_SUB_RC: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_SUB);
			break;
		}
		case DUK_OP_SUB_CC: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_SUB);
			break;
		}
		case DUK_OP_MUL_RR: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_MUL);
			break;
		}
		case DUK_OP_MUL_CR: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_MUL);
			break;
		}
		case DUK_OP_MUL_RC: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_MUL);
			break;
		}
		case DUK_OP_MUL_CC: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_MUL);
			break;
		}
		case DUK_OP_DIV_RR: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_DIV);
			break;
		}
		case DUK_OP_DIV_CR: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_DIV);
			break;
		}
		case DUK_OP_DIV_RC: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_DIV);
			break;
		}
		case DUK_OP_DIV_CC: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_DIV);
			break;
		}
		case DUK_OP_MOD_RR: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_MOD);
			break;
		}
		case DUK_OP_MOD_CR: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_MOD);
			break;
		}
		case DUK_OP_MOD_RC: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_MOD);
			break;
		}
		case DUK_OP_MOD_CC: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_MOD);
			break;
		}
#if defined(DUK_USE_ES7_EXP_OPERATOR)
		case DUK_OP_EXP_RR: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_EXP);
			break;
		}
		case DUK_OP_EXP_CR: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_EXP);
			break;
		}
		case DUK_OP_EXP_RC: {
			duk__vm_arith_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_EXP);
			break;
		}
		case DUK_OP_EXP_CC: {
			duk__vm_arith_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_EXP);
			break;
		}
#endif  /* DUK_USE_ES7_EXP_OPERATOR */
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_BAND_RR:
		case DUK_OP_BAND_CR:
		case DUK_OP_BAND_RC:
		case DUK_OP_BAND_CC:
		case DUK_OP_BOR_RR:
		case DUK_OP_BOR_CR:
		case DUK_OP_BOR_RC:
		case DUK_OP_BOR_CC:
		case DUK_OP_BXOR_RR:
		case DUK_OP_BXOR_CR:
		case DUK_OP_BXOR_RC:
		case DUK_OP_BXOR_CC:
		case DUK_OP_BASL_RR:
		case DUK_OP_BASL_CR:
		case DUK_OP_BASL_RC:
		case DUK_OP_BASL_CC:
		case DUK_OP_BLSR_RR:
		case DUK_OP_BLSR_CR:
		case DUK_OP_BLSR_RC:
		case DUK_OP_BLSR_CC:
		case DUK_OP_BASR_RR:
		case DUK_OP_BASR_CR:
		case DUK_OP_BASR_RC:
		case DUK_OP_BASR_CC: {
			/* XXX: could leave value on stack top and goto replace_top_a; */
			duk__vm_bitwise_binary_op(thr, DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins), DUK_DEC_A(ins), op);
			break;
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_BAND_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BAND);
			break;
		}
		case DUK_OP_BAND_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BAND);
			break;
		}
		case DUK_OP_BAND_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BAND);
			break;
		}
		case DUK_OP_BAND_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BAND);
			break;
		}
		case DUK_OP_BOR_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BOR);
			break;
		}
		case DUK_OP_BOR_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BOR);
			break;
		}
		case DUK_OP_BOR_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BOR);
			break;
		}
		case DUK_OP_BOR_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BOR);
			break;
		}
		case DUK_OP_BXOR_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BXOR);
			break;
		}
		case DUK_OP_BXOR_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BXOR);
			break;
		}
		case DUK_OP_BXOR_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BXOR);
			break;
		}
		case DUK_OP_BXOR_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BXOR);
			break;
		}
		case DUK_OP_BASL_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BASL);
			break;
		}
		case DUK_OP_BASL_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BASL);
			break;
		}
		case DUK_OP_BASL_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BASL);
			break;
		}
		case DUK_OP_BASL_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BASL);
			break;
		}
		case DUK_OP_BLSR_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BLSR);
			break;
		}
		case DUK_OP_BLSR_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BLSR);
			break;
		}
		case DUK_OP_BLSR_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BLSR);
			break;
		}
		case DUK_OP_BLSR_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BLSR);
			break;
		}
		case DUK_OP_BASR_RR: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BASR);
			break;
		}
		case DUK_OP_BASR_CR: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__REGP_C(ins), DUK_DEC_A(ins), DUK_OP_BASR);
			break;
		}
		case DUK_OP_BASR_RC: {
			duk__vm_bitwise_binary_op(thr, DUK__REGP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BASR);
			break;
		}
		case DUK_OP_BASR_CC: {
			duk__vm_bitwise_binary_op(thr, DUK__CONSTP_B(ins), DUK__CONSTP_C(ins), DUK_DEC_A(ins), DUK_OP_BASR);
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		/* For INSTOF and IN, B is always a register. */
#define DUK__INSTOF_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_instanceof(thr, (barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#define DUK__IN_BODY(barg,carg) { \
		duk_bool_t tmp; \
		tmp = duk_js_in(thr, (barg), (carg)); \
		DUK_ASSERT(tmp == 0 || tmp == 1); \
		DUK__REPLACE_BOOL_A_BREAK(tmp); \
	}
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_INSTOF_RR:
		case DUK_OP_INSTOF_CR:
		case DUK_OP_INSTOF_RC:
		case DUK_OP_INSTOF_CC:
			DUK__INSTOF_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_IN_RR:
		case DUK_OP_IN_CR:
		case DUK_OP_IN_RC:
		case DUK_OP_IN_CC:
			DUK__IN_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_INSTOF_RR:
			DUK__INSTOF_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_INSTOF_CR:
			DUK__INSTOF_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_INSTOF_RC:
			DUK__INSTOF_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_INSTOF_CC:
			DUK__INSTOF_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_IN_RR:
			DUK__IN_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_IN_CR:
			DUK__IN_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_IN_RC:
			DUK__IN_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_IN_CC:
			DUK__IN_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		/* Pre/post inc/dec for register variables, important for loops. */
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_PREINCR:
		case DUK_OP_PREDECR:
		case DUK_OP_POSTINCR:
		case DUK_OP_POSTDECR: {
			duk__prepost_incdec_reg_helper(thr, DUK__REGP_A(ins), DUK__REGP_BC(ins), op);
			break;
		}
		case DUK_OP_PREINCV:
		case DUK_OP_PREDECV:
		case DUK_OP_POSTINCV:
		case DUK_OP_POSTDECV: {
			duk__prepost_incdec_var_helper(thr, DUK_DEC_A(ins), DUK__CONSTP_BC(ins), op, DUK__STRICT());
			break;
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_PREINCR: {
			duk__prepost_incdec_reg_helper(thr, DUK__REGP_A(ins), DUK__REGP_BC(ins), DUK_OP_PREINCR);
			break;
		}
		case DUK_OP_PREDECR: {
			duk__prepost_incdec_reg_helper(thr, DUK__REGP_A(ins), DUK__REGP_BC(ins), DUK_OP_PREDECR);
			break;
		}
		case DUK_OP_POSTINCR: {
			duk__prepost_incdec_reg_helper(thr, DUK__REGP_A(ins), DUK__REGP_BC(ins), DUK_OP_POSTINCR);
			break;
		}
		case DUK_OP_POSTDECR: {
			duk__prepost_incdec_reg_helper(thr, DUK__REGP_A(ins), DUK__REGP_BC(ins), DUK_OP_POSTDECR);
			break;
		}
		case DUK_OP_PREINCV: {
			duk__prepost_incdec_var_helper(thr, DUK_DEC_A(ins), DUK__CONSTP_BC(ins), DUK_OP_PREINCV, DUK__STRICT());
			break;
		}
		case DUK_OP_PREDECV: {
			duk__prepost_incdec_var_helper(thr, DUK_DEC_A(ins), DUK__CONSTP_BC(ins), DUK_OP_PREDECV, DUK__STRICT());
			break;
		}
		case DUK_OP_POSTINCV: {
			duk__prepost_incdec_var_helper(thr, DUK_DEC_A(ins), DUK__CONSTP_BC(ins), DUK_OP_POSTINCV, DUK__STRICT());
			break;
		}
		case DUK_OP_POSTDECV: {
			duk__prepost_incdec_var_helper(thr, DUK_DEC_A(ins), DUK__CONSTP_BC(ins), DUK_OP_POSTDECV, DUK__STRICT());
			break;
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		/* XXX: Move to separate helper, optimize for perf/size separately. */
		/* Preinc/predec for object properties. */
		case DUK_OP_PREINCP_RR:
		case DUK_OP_PREINCP_CR:
		case DUK_OP_PREINCP_RC:
		case DUK_OP_PREINCP_CC:
		case DUK_OP_PREDECP_RR:
		case DUK_OP_PREDECP_CR:
		case DUK_OP_PREDECP_RC:
		case DUK_OP_PREDECP_CC:
		case DUK_OP_POSTINCP_RR:
		case DUK_OP_POSTINCP_CR:
		case DUK_OP_POSTINCP_RC:
		case DUK_OP_POSTINCP_CC:
		case DUK_OP_POSTDECP_RR:
		case DUK_OP_POSTDECP_CR:
		case DUK_OP_POSTDECP_RC:
		case DUK_OP_POSTDECP_CC: {
			duk_tval *tv_obj;
			duk_tval *tv_key;
			duk_tval *tv_val;
			duk_bool_t rc;
			duk_double_t x, y, z;
#if !defined(DUK_USE_EXEC_PREFER_SIZE)
			duk_tval *tv_dst;
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

			/* A -> target reg
			 * B -> object reg/const (may be const e.g. in "'foo'[1]")
			 * C -> key reg/const
			 */

			/* Opcode bits 0-1 are used to distinguish reg/const variants.
			 * Opcode bits 2-3 are used to distinguish inc/dec variants:
			 * Bit 2 = inc(0)/dec(1), bit 3 = pre(0)/post(1).
			 */
			DUK_ASSERT((DUK_OP_PREINCP_RR & 0x0c) == 0x00);
			DUK_ASSERT((DUK_OP_PREDECP_RR & 0x0c) == 0x04);
			DUK_ASSERT((DUK_OP_POSTINCP_RR & 0x0c) == 0x08);
			DUK_ASSERT((DUK_OP_POSTDECP_RR & 0x0c) == 0x0c);

			tv_obj = DUK__REGCONSTP_B(ins);
			tv_key = DUK__REGCONSTP_C(ins);
			rc = duk_hobject_getprop(thr, tv_obj, tv_key);  /* -> [val] */
			DUK_UNREF(rc);  /* ignore */
			tv_obj = NULL;  /* invalidated */
			tv_key = NULL;  /* invalidated */

			/* XXX: Fastint fast path would be useful here.  Also fastints
			 * now lose their fastint status in current handling which is
			 * not intuitive.
			 */

			x = duk_to_number_m1(thr);
			duk_pop_unsafe(thr);
			if (ins & DUK_BC_INCDECP_FLAG_DEC) {
				y = x - 1.0;
			} else {
				y = x + 1.0;
			}

			duk_push_number(thr, y);
			tv_val = DUK_GET_TVAL_NEGIDX(thr, -1);
			DUK_ASSERT(tv_val != NULL);
			tv_obj = DUK__REGCONSTP_B(ins);
			tv_key = DUK__REGCONSTP_C(ins);
			rc = duk_hobject_putprop(thr, tv_obj, tv_key, tv_val, DUK__STRICT());
			DUK_UNREF(rc);  /* ignore */
			tv_obj = NULL;  /* invalidated */
			tv_key = NULL;  /* invalidated */
			duk_pop_unsafe(thr);

			z = (ins & DUK_BC_INCDECP_FLAG_POST) ? x : y;
#if defined(DUK_USE_EXEC_PREFER_SIZE)
			duk_push_number(thr, z);
			DUK__REPLACE_TOP_A_BREAK();
#else
			tv_dst = DUK__REGP_A(ins);
			DUK_TVAL_SET_NUMBER_UPDREF(thr, tv_dst, z);
			break;
#endif
		}

		/* XXX: GETPROP where object is 'this', GETPROPT?
		 * Occurs relatively often in object oriented code.
		 */

#define DUK__GETPROP_BODY(barg,carg) { \
		/* A -> target reg \
		 * B -> object reg/const (may be const e.g. in "'foo'[1]") \
		 * C -> key reg/const \
		 */ \
		(void) duk_hobject_getprop(thr, (barg), (carg)); \
		DUK__REPLACE_TOP_A_BREAK(); \
	}
#define DUK__GETPROPC_BODY(barg,carg) { \
		/* Same as GETPROP but callability check for property-based calls. */ \
		duk_tval *tv__targ; \
		(void) duk_hobject_getprop(thr, (barg), (carg)); \
		DUK_GC_TORTURE(thr->heap); \
		tv__targ = DUK_GET_TVAL_NEGIDX(thr, -1); \
		if (DUK_UNLIKELY(!duk_is_callable_tval(thr, tv__targ))) { \
			/* Here we intentionally re-evaluate the macro \
			 * arguments to deal with potentially changed \
			 * valstack base pointer! \
			 */ \
			duk_call_setup_propcall_error(thr, (barg), (carg)); \
		} \
		DUK__REPLACE_TOP_A_BREAK(); \
	}
#define DUK__PUTPROP_BODY(aarg,barg,carg) { \
		/* A -> object reg \
		 * B -> key reg/const \
		 * C -> value reg/const \
		 * \
		 * Note: intentional difference to register arrangement \
		 * of e.g. GETPROP; 'A' must contain a register-only value. \
		 */ \
		(void) duk_hobject_putprop(thr, (aarg), (barg), (carg), DUK__STRICT()); \
		break; \
	}
#define DUK__DELPROP_BODY(barg,carg) { \
		/* A -> result reg \
		 * B -> object reg \
		 * C -> key reg/const \
		 */ \
		duk_bool_t rc; \
		rc = duk_hobject_delprop(thr, (barg), (carg), DUK__STRICT()); \
		DUK_ASSERT(rc == 0 || rc == 1); \
		DUK__REPLACE_BOOL_A_BREAK(rc); \
	}
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_GETPROP_RR:
		case DUK_OP_GETPROP_CR:
		case DUK_OP_GETPROP_RC:
		case DUK_OP_GETPROP_CC:
			DUK__GETPROP_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
#if defined(DUK_USE_VERBOSE_ERRORS)
		case DUK_OP_GETPROPC_RR:
		case DUK_OP_GETPROPC_CR:
		case DUK_OP_GETPROPC_RC:
		case DUK_OP_GETPROPC_CC:
			DUK__GETPROPC_BODY(DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
#endif
		case DUK_OP_PUTPROP_RR:
		case DUK_OP_PUTPROP_CR:
		case DUK_OP_PUTPROP_RC:
		case DUK_OP_PUTPROP_CC:
			DUK__PUTPROP_BODY(DUK__REGP_A(ins), DUK__REGCONSTP_B(ins), DUK__REGCONSTP_C(ins));
		case DUK_OP_DELPROP_RR:
		case DUK_OP_DELPROP_RC:  /* B is always reg */
			DUK__DELPROP_BODY(DUK__REGP_B(ins), DUK__REGCONSTP_C(ins));
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_GETPROP_RR:
			DUK__GETPROP_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GETPROP_CR:
			DUK__GETPROP_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GETPROP_RC:
			DUK__GETPROP_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_GETPROP_CC:
			DUK__GETPROP_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
#if defined(DUK_USE_VERBOSE_ERRORS)
		case DUK_OP_GETPROPC_RR:
			DUK__GETPROPC_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GETPROPC_CR:
			DUK__GETPROPC_BODY(DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_GETPROPC_RC:
			DUK__GETPROPC_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_GETPROPC_CC:
			DUK__GETPROPC_BODY(DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
#endif
		case DUK_OP_PUTPROP_RR:
			DUK__PUTPROP_BODY(DUK__REGP_A(ins), DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_PUTPROP_CR:
			DUK__PUTPROP_BODY(DUK__REGP_A(ins), DUK__CONSTP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_PUTPROP_RC:
			DUK__PUTPROP_BODY(DUK__REGP_A(ins), DUK__REGP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_PUTPROP_CC:
			DUK__PUTPROP_BODY(DUK__REGP_A(ins), DUK__CONSTP_B(ins), DUK__CONSTP_C(ins));
		case DUK_OP_DELPROP_RR:  /* B is always reg */
			DUK__DELPROP_BODY(DUK__REGP_B(ins), DUK__REGP_C(ins));
		case DUK_OP_DELPROP_RC:
			DUK__DELPROP_BODY(DUK__REGP_B(ins), DUK__CONSTP_C(ins));
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		/* No fast path for DECLVAR now, it's quite a rare instruction. */
		case DUK_OP_DECLVAR_RR:
		case DUK_OP_DECLVAR_CR:
		case DUK_OP_DECLVAR_RC:
		case DUK_OP_DECLVAR_CC: {
			duk_activation *act;
			duk_small_uint_fast_t a = DUK_DEC_A(ins);
			duk_tval *tv1;
			duk_hstring *name;
			duk_small_uint_t prop_flags;
			duk_bool_t is_func_decl;

			tv1 = DUK__REGCONSTP_B(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));
			name = DUK_TVAL_GET_STRING(tv1);
			DUK_ASSERT(name != NULL);

			is_func_decl = ((a & DUK_BC_DECLVAR_FLAG_FUNC_DECL) != 0);

			/* XXX: declvar takes an duk_tval pointer, which is awkward and
			 * should be reworked.
			 */

			/* Compiler is responsible for selecting property flags (configurability,
			 * writability, etc).
			 */
			prop_flags = a & DUK_PROPDESC_FLAGS_MASK;

			if (is_func_decl) {
				duk_push_tval(thr, DUK__REGCONSTP_C(ins));
			} else {
				DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));  /* valstack policy */
				thr->valstack_top++;
			}
			tv1 = DUK_GET_TVAL_NEGIDX(thr, -1);

			act = thr->callstack_curr;
			if (duk_js_declvar_activation(thr, act, name, tv1, prop_flags, is_func_decl)) {
				if (is_func_decl) {
					/* Already declared, update value. */
					tv1 = DUK_GET_TVAL_NEGIDX(thr, -1);
					duk_js_putvar_activation(thr, act, name, tv1, DUK__STRICT());
				} else {
					/* Already declared but no initializer value
					 * (e.g. 'var xyz;'), no-op.
					 */
				}
			}

			duk_pop_unsafe(thr);
			break;
		}

#if defined(DUK_USE_REGEXP_SUPPORT)
		/* The compiler should never emit DUK_OP_REGEXP if there is no
		 * regexp support.
		 */
		case DUK_OP_REGEXP_RR:
		case DUK_OP_REGEXP_CR:
		case DUK_OP_REGEXP_RC:
		case DUK_OP_REGEXP_CC: {
			/* A -> target register
			 * B -> bytecode (also contains flags)
			 * C -> escaped source
			 */

			duk_push_tval(thr, DUK__REGCONSTP_C(ins));
			duk_push_tval(thr, DUK__REGCONSTP_B(ins));  /* -> [ ... escaped_source bytecode ] */
			duk_regexp_create_instance(thr);   /* -> [ ... regexp_instance ] */
			DUK__REPLACE_TOP_A_BREAK();
		}
#endif  /* DUK_USE_REGEXP_SUPPORT */

		/* XXX: 'c' is unused, use whole BC, etc. */
		case DUK_OP_CSVAR_RR:
		case DUK_OP_CSVAR_CR:
		case DUK_OP_CSVAR_RC:
		case DUK_OP_CSVAR_CC: {
			/* The speciality of calling through a variable binding is that the
			 * 'this' value may be provided by the variable lookup: E5 Section 6.b.i.
			 *
			 * The only (standard) case where the 'this' binding is non-null is when
			 *   (1) the variable is found in an object environment record, and
			 *   (2) that object environment record is a 'with' block.
			 */

			duk_activation *act;
			duk_uint_fast_t idx;
			duk_tval *tv1;
			duk_hstring *name;

			/* A -> target registers (A, A + 1) for call setup
			 * B -> identifier name, usually constant but can be a register due to shuffling
			 */

			tv1 = DUK__REGCONSTP_B(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));
			name = DUK_TVAL_GET_STRING(tv1);
			DUK_ASSERT(name != NULL);
			act = thr->callstack_curr;
			(void) duk_js_getvar_activation(thr, act, name, 1 /*throw*/);  /* -> [... val this] */

			idx = (duk_uint_fast_t) DUK_DEC_A(ins);

			/* Could add direct value stack handling. */
			duk_replace(thr, (duk_idx_t) (idx + 1));  /* 'this' binding */
			duk_replace(thr, (duk_idx_t) idx);        /* variable value (function, we hope, not checked here) */
			break;
		}

		case DUK_OP_CLOSURE: {
			duk_activation *act;
			duk_hcompfunc *fun_act;
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);
			duk_hobject *fun_temp;

			/* A -> target reg
			 * BC -> inner function index
			 */

			DUK_DDD(DUK_DDDPRINT("CLOSURE to target register %ld, fnum %ld (count %ld)",
			                     (long) DUK_DEC_A(ins), (long) DUK_DEC_BC(ins), (long) DUK_HCOMPFUNC_GET_FUNCS_COUNT(thr->heap, DUK__FUN())));

			DUK_ASSERT_DISABLE(bc >= 0); /* unsigned */
			DUK_ASSERT((duk_uint_t) bc < (duk_uint_t) DUK_HCOMPFUNC_GET_FUNCS_COUNT(thr->heap, DUK__FUN()));

			act = thr->callstack_curr;
			fun_act = (duk_hcompfunc *) DUK_ACT_GET_FUNC(act);
			fun_temp = DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, fun_act)[bc];
			DUK_ASSERT(fun_temp != NULL);
			DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(fun_temp));

			DUK_DDD(DUK_DDDPRINT("CLOSURE: function template is: %p -> %!O",
			                     (void *) fun_temp, (duk_heaphdr *) fun_temp));

			if (act->lex_env == NULL) {
				DUK_ASSERT(act->var_env == NULL);
				duk_js_init_activation_environment_records_delayed(thr, act);
				act = thr->callstack_curr;
			}
			DUK_ASSERT(act->lex_env != NULL);
			DUK_ASSERT(act->var_env != NULL);

			/* functions always have a NEWENV flag, i.e. they get a
			 * new variable declaration environment, so only lex_env
			 * matters here.
			 */
			duk_js_push_closure(thr,
			                    (duk_hcompfunc *) fun_temp,
			                    act->var_env,
			                    act->lex_env,
			                    1 /*add_auto_proto*/);
			DUK__REPLACE_TOP_A_BREAK();
		}

		case DUK_OP_GETVAR: {
			duk_activation *act;
			duk_tval *tv1;
			duk_hstring *name;

			tv1 = DUK__CONSTP_BC(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));
			name = DUK_TVAL_GET_STRING(tv1);
			DUK_ASSERT(name != NULL);
			act = thr->callstack_curr;
			DUK_ASSERT(act != NULL);
			(void) duk_js_getvar_activation(thr, act, name, 1 /*throw*/);  /* -> [... val this] */
			duk_pop_unsafe(thr);  /* 'this' binding is not needed here */
			DUK__REPLACE_TOP_A_BREAK();
		}

		case DUK_OP_PUTVAR: {
			duk_activation *act;
			duk_tval *tv1;
			duk_hstring *name;

			tv1 = DUK__CONSTP_BC(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));
			name = DUK_TVAL_GET_STRING(tv1);
			DUK_ASSERT(name != NULL);

			/* XXX: putvar takes a duk_tval pointer, which is awkward and
			 * should be reworked.
			 */

			tv1 = DUK__REGP_A(ins);  /* val */
			act = thr->callstack_curr;
			duk_js_putvar_activation(thr, act, name, tv1, DUK__STRICT());
			break;
		}

		case DUK_OP_DELVAR: {
			duk_activation *act;
			duk_tval *tv1;
			duk_hstring *name;
			duk_bool_t rc;

			tv1 = DUK__CONSTP_BC(ins);
			DUK_ASSERT(DUK_TVAL_IS_STRING(tv1));
			name = DUK_TVAL_GET_STRING(tv1);
			DUK_ASSERT(name != NULL);
			act = thr->callstack_curr;
			rc = duk_js_delvar_activation(thr, act, name);
			DUK__REPLACE_BOOL_A_BREAK(rc);
		}

		case DUK_OP_JUMP: {
			/* Note: without explicit cast to signed, MSVC will
			 * apparently generate a large positive jump when the
			 * bias-corrected value would normally be negative.
			 */
			curr_pc += (duk_int_fast_t) DUK_DEC_ABC(ins) - (duk_int_fast_t) DUK_BC_JUMP_BIAS;
			break;
		}

#define DUK__RETURN_SHARED() do { \
		duk_small_uint_t ret_result; \
		/* duk__handle_return() is guaranteed never to throw, except \
		 * for potential out-of-memory situations which will then \
		 * propagate out of the executor longjmp handler. \
		 */ \
		DUK_ASSERT(thr->ptr_curr_pc == NULL); \
		ret_result = duk__handle_return(thr, entry_act); \
		if (ret_result == DUK__RETHAND_RESTART) { \
			goto restart_execution; \
		} \
		DUK_ASSERT(ret_result == DUK__RETHAND_FINISHED); \
		return; \
	} while (0)
#if defined(DUK_USE_EXEC_PREFER_SIZE)
		case DUK_OP_RETREG:
		case DUK_OP_RETCONST:
		case DUK_OP_RETCONSTN:
		case DUK_OP_RETUNDEF: {
			 /* BC -> return value reg/const */

			DUK__SYNC_AND_NULL_CURR_PC();

			if (op == DUK_OP_RETREG) {
				duk_push_tval(thr, DUK__REGP_BC(ins));
			} else if (op == DUK_OP_RETUNDEF) {
				DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));  /* valstack policy */
				thr->valstack_top++;
			} else {
				DUK_ASSERT(op == DUK_OP_RETCONST || op == DUK_OP_RETCONSTN);
				duk_push_tval(thr, DUK__CONSTP_BC(ins));
			}

			DUK__RETURN_SHARED();
		}
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		case DUK_OP_RETREG: {
			duk_tval *tv;

			DUK__SYNC_AND_NULL_CURR_PC();
			tv = DUK__REGP_BC(ins);
			DUK_TVAL_SET_TVAL(thr->valstack_top, tv);
			DUK_TVAL_INCREF(thr, tv);
			thr->valstack_top++;
			DUK__RETURN_SHARED();
		}
		/* This will be unused without refcounting. */
		case DUK_OP_RETCONST: {
			duk_tval *tv;

			DUK__SYNC_AND_NULL_CURR_PC();
			tv = DUK__CONSTP_BC(ins);
			DUK_TVAL_SET_TVAL(thr->valstack_top, tv);
			DUK_TVAL_INCREF(thr, tv);
			thr->valstack_top++;
			DUK__RETURN_SHARED();
		}
		case DUK_OP_RETCONSTN: {
			duk_tval *tv;

			DUK__SYNC_AND_NULL_CURR_PC();
			tv = DUK__CONSTP_BC(ins);
			DUK_TVAL_SET_TVAL(thr->valstack_top, tv);
#if defined(DUK_USE_REFERENCE_COUNTING)
			/* Without refcounting only RETCONSTN is used. */
			DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv));  /* no INCREF for this constant */
#endif
			thr->valstack_top++;
			DUK__RETURN_SHARED();
		}
		case DUK_OP_RETUNDEF: {
			DUK__SYNC_AND_NULL_CURR_PC();
			thr->valstack_top++;  /* value at valstack top is already undefined by valstack policy */
			DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));
			DUK__RETURN_SHARED();
		}
#endif  /* DUK_USE_EXEC_PREFER_SIZE */

		case DUK_OP_LABEL: {
			duk_activation *act;
			duk_catcher *cat;
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);

			/* Allocate catcher and populate it (must be atomic). */

			cat = duk_hthread_catcher_alloc(thr);
			DUK_ASSERT(cat != NULL);

			cat->flags = (duk_uint32_t) (DUK_CAT_TYPE_LABEL | (bc << DUK_CAT_LABEL_SHIFT));
			cat->pc_base = (duk_instr_t *) curr_pc;  /* pre-incremented, points to first jump slot */
			cat->idx_base = 0;  /* unused for label */
			cat->h_varname = NULL;

			act = thr->callstack_curr;
			DUK_ASSERT(act != NULL);
			cat->parent = act->cat;
			act->cat = cat;

			DUK_DDD(DUK_DDDPRINT("LABEL catcher: flags=0x%08lx, pc_base=%ld, "
			                     "idx_base=%ld, h_varname=%!O, label_id=%ld",
			                     (long) cat->flags, (long) cat->pc_base,
			                     (long) cat->idx_base, (duk_heaphdr *) cat->h_varname, (long) DUK_CAT_GET_LABEL(cat)));

			curr_pc += 2;  /* skip jump slots */
			break;
		}

		case DUK_OP_ENDLABEL: {
			duk_activation *act;
#if (defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)) || defined(DUK_USE_ASSERTIONS)
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);
#endif
#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
			DUK_DDD(DUK_DDDPRINT("ENDLABEL %ld", (long) bc));
#endif

			act = thr->callstack_curr;
			DUK_ASSERT(act->cat != NULL);
			DUK_ASSERT(DUK_CAT_GET_TYPE(act->cat) == DUK_CAT_TYPE_LABEL);
			DUK_ASSERT((duk_uint_fast_t) DUK_CAT_GET_LABEL(act->cat) == bc);
			duk_hthread_catcher_unwind_nolexenv_norz(thr, act);

			/* no need to unwind callstack */
			break;
		}

		case DUK_OP_BREAK: {
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);

			DUK__SYNC_AND_NULL_CURR_PC();
			duk__handle_break_or_continue(thr, (duk_uint_t) bc, DUK_LJ_TYPE_BREAK);
			goto restart_execution;
		}

		case DUK_OP_CONTINUE: {
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);

			DUK__SYNC_AND_NULL_CURR_PC();
			duk__handle_break_or_continue(thr, (duk_uint_t) bc, DUK_LJ_TYPE_CONTINUE);
			goto restart_execution;
		}

		/* XXX: move to helper, too large to be inline here */
		case DUK_OP_TRYCATCH: {
			duk__handle_op_trycatch(thr, ins, curr_pc);
			curr_pc += 2;  /* skip jump slots */
			break;
		}

		case DUK_OP_ENDTRY: {
			curr_pc = duk__handle_op_endtry(thr, ins);
			break;
		}

		case DUK_OP_ENDCATCH: {
			duk__handle_op_endcatch(thr, ins);
			break;
		}

		case DUK_OP_ENDFIN: {
			/* Sync and NULL early. */
			DUK__SYNC_AND_NULL_CURR_PC();

			if (duk__handle_op_endfin(thr, ins, entry_act) != 0) {
				return;
			}

			/* Must restart because we NULLed out curr_pc. */
			goto restart_execution;
		}

		case DUK_OP_THROW: {
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);

			/* Note: errors are augmented when they are created, not
			 * when they are thrown.  So, don't augment here, it would
			 * break re-throwing for instance.
			 */

			/* Sync so that augmentation sees up-to-date activations, NULL
			 * thr->ptr_curr_pc so that it's not used if side effects occur
			 * in augmentation or longjmp handling.
			 */
			DUK__SYNC_AND_NULL_CURR_PC();

			duk_dup(thr, (duk_idx_t) bc);
			DUK_DDD(DUK_DDDPRINT("THROW ERROR (BYTECODE): %!dT (before throw augment)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
#if defined(DUK_USE_AUGMENT_ERROR_THROW)
			duk_err_augment_error_throw(thr);
			DUK_DDD(DUK_DDDPRINT("THROW ERROR (BYTECODE): %!dT (after throw augment)",
			                     (duk_tval *) duk_get_tval(thr, -1)));
#endif

			duk_err_setup_ljstate1(thr, DUK_LJ_TYPE_THROW, DUK_GET_TVAL_NEGIDX(thr, -1));
#if defined(DUK_USE_DEBUGGER_SUPPORT)
			duk_err_check_debugger_integration(thr);
#endif

			DUK_ASSERT(thr->heap->lj.jmpbuf_ptr != NULL);  /* always in executor */
			duk_err_longjmp(thr);
			DUK_UNREACHABLE();
			break;
		}

		case DUK_OP_CSREG: {
			/*
			 *  Assuming a register binds to a variable declared within this
			 *  function (a declarative binding), the 'this' for the call
			 *  setup is always 'undefined'.  E5 Section 10.2.1.1.6.
			 */

			duk_small_uint_fast_t a = DUK_DEC_A(ins);
			duk_small_uint_fast_t bc = DUK_DEC_BC(ins);

			/* A -> register containing target function (not type checked here)
			 * BC -> target registers (BC, BC + 1) for call setup
			 */

#if defined(DUK_USE_PREFER_SIZE)
			duk_dup(thr, (duk_idx_t) a);
			duk_replace(thr, (duk_idx_t) bc);
			duk_to_undefined(thr, (duk_idx_t) (bc + 1));
#else
			duk_tval *tv1;
			duk_tval *tv2;
			duk_tval *tv3;
			duk_tval tv_tmp1;
			duk_tval tv_tmp2;

			tv1 = DUK__REGP(bc);
			tv2 = tv1 + 1;
			DUK_TVAL_SET_TVAL(&tv_tmp1, tv1);
			DUK_TVAL_SET_TVAL(&tv_tmp2, tv2);
			tv3 = DUK__REGP(a);
			DUK_TVAL_SET_TVAL(tv1, tv3);
			DUK_TVAL_INCREF(thr, tv1);  /* no side effects */
			DUK_TVAL_SET_UNDEFINED(tv2);  /* no need for incref */
			DUK_TVAL_DECREF(thr, &tv_tmp1);
			DUK_TVAL_DECREF(thr, &tv_tmp2);
#endif
			break;
		}


		/* XXX: in some cases it's faster NOT to reuse the value
		 * stack but rather copy the arguments on top of the stack
		 * (mainly when the calling value stack is large and the value
		 * stack resize would be large).
		 */

		case DUK_OP_CALL0:
		case DUK_OP_CALL1:
		case DUK_OP_CALL2:
		case DUK_OP_CALL3:
		case DUK_OP_CALL4:
		case DUK_OP_CALL5:
		case DUK_OP_CALL6:
		case DUK_OP_CALL7: {
			/* Opcode packs 4 flag bits: 1 for indirect, 3 map
			 * 1:1 to three lowest call handling flags.
			 *
			 * A -> nargs or register with nargs (indirect)
			 * BC -> base register for call (base -> func, base+1 -> this, base+2 -> arg1 ... base+2+N-1 -> argN)
			 */

			duk_idx_t nargs;
			duk_idx_t idx;
			duk_small_uint_t call_flags;
#if !defined(DUK_USE_EXEC_FUN_LOCAL)
			duk_hcompfunc *fun;
#endif

			DUK_ASSERT((DUK_OP_CALL0 & 0x0fU) == 0);
			DUK_ASSERT((ins & DUK_BC_CALL_FLAG_INDIRECT) == 0);

			nargs = (duk_idx_t) DUK_DEC_A(ins);
			call_flags = (ins & 0x07U) | DUK_CALL_FLAG_ALLOW_ECMATOECMA;
			idx = (duk_idx_t) DUK_DEC_BC(ins);

			if (duk__executor_handle_call(thr, idx, nargs, call_flags)) {
				/* curr_pc synced by duk_handle_call_unprotected() */
				DUK_ASSERT(thr->ptr_curr_pc == NULL);
				goto restart_execution;
			}
			DUK_ASSERT(thr->ptr_curr_pc != NULL);

			/* duk_js_call.c is required to restore the stack reserve
			 * so we only need to reset the top.
			 */
#if !defined(DUK_USE_EXEC_FUN_LOCAL)
			fun = DUK__FUN();
#endif
			duk_set_top_unsafe(thr, (duk_idx_t) fun->nregs);

			/* No need to reinit setjmp() catchpoint, as call handling
			 * will store and restore our state.
			 *
			 * When debugger is enabled, we need to recheck the activation
			 * status after returning.  This is now handled by call handling
			 * and heap->dbg_force_restart.
			 */
			break;
		}

		case DUK_OP_CALL8:
		case DUK_OP_CALL9:
		case DUK_OP_CALL10:
		case DUK_OP_CALL11:
		case DUK_OP_CALL12:
		case DUK_OP_CALL13:
		case DUK_OP_CALL14:
		case DUK_OP_CALL15: {
			/* Indirect variant. */
			duk_uint_fast_t nargs;
			duk_idx_t idx;
			duk_small_uint_t call_flags;
#if !defined(DUK_USE_EXEC_FUN_LOCAL)
			duk_hcompfunc *fun;
#endif

			DUK_ASSERT((DUK_OP_CALL0 & 0x0fU) == 0);
			DUK_ASSERT((ins & DUK_BC_CALL_FLAG_INDIRECT) != 0);

			nargs = (duk_uint_fast_t) DUK_DEC_A(ins);
			DUK__LOOKUP_INDIRECT(nargs);
			call_flags = (ins & 0x07U) | DUK_CALL_FLAG_ALLOW_ECMATOECMA;
			idx = (duk_idx_t) DUK_DEC_BC(ins);

			if (duk__executor_handle_call(thr, idx, (duk_idx_t) nargs, call_flags)) {
				DUK_ASSERT(thr->ptr_curr_pc == NULL);
				goto restart_execution;
			}
			DUK_ASSERT(thr->ptr_curr_pc != NULL);

#if !defined(DUK_USE_EXEC_FUN_LOCAL)
			fun = DUK__FUN();
#endif
			duk_set_top_unsafe(thr, (duk_idx_t) fun->nregs);
			break;
		}

		case DUK_OP_NEWOBJ: {
			duk_push_object(thr);
#if defined(DUK_USE_ASSERTIONS)
			{
				duk_hobject *h;
				h = duk_require_hobject(thr, -1);
				DUK_ASSERT(DUK_HOBJECT_GET_ESIZE(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_ASIZE(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_HSIZE(h) == 0);
			}
#endif
#if !defined(DUK_USE_PREFER_SIZE)
			/* XXX: could do a direct props realloc, but need hash size */
			duk_hobject_resize_entrypart(thr, duk_known_hobject(thr, -1), DUK_DEC_A(ins));
#endif
			DUK__REPLACE_TOP_BC_BREAK();
		}

		case DUK_OP_NEWARR: {
			duk_push_array(thr);
#if defined(DUK_USE_ASSERTIONS)
			{
				duk_hobject *h;
				h = duk_require_hobject(thr, -1);
				DUK_ASSERT(DUK_HOBJECT_GET_ESIZE(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_ENEXT(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_ASIZE(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_GET_HSIZE(h) == 0);
				DUK_ASSERT(DUK_HOBJECT_HAS_ARRAY_PART(h));
			}
#endif
#if !defined(DUK_USE_PREFER_SIZE)
			duk_hobject_realloc_props(thr,
			                          duk_known_hobject(thr, -1),
			                          0 /*new_e_size*/,
			                          DUK_DEC_A(ins) /*new_a_size*/,
			                          0 /*new_h_size*/,
			                          0 /*abandon_array*/);
#if 0
			duk_hobject_resize_arraypart(thr, duk_known_hobject(thr, -1), DUK_DEC_A(ins));
#endif
#endif
			DUK__REPLACE_TOP_BC_BREAK();
		}

		case DUK_OP_MPUTOBJ:
		case DUK_OP_MPUTOBJI: {
			duk_idx_t obj_idx;
			duk_uint_fast_t idx, idx_end;
			duk_small_uint_fast_t count;

			/* A -> register of target object
			 * B -> first register of key/value pair list
			 *      or register containing first register number if indirect
			 * C -> number of key/value pairs * 2
			 *      (= number of value stack indices used starting from 'B')
			 */

			obj_idx = DUK_DEC_A(ins);
			DUK_ASSERT(duk_is_object(thr, obj_idx));

			idx = (duk_uint_fast_t) DUK_DEC_B(ins);
			if (DUK_DEC_OP(ins) == DUK_OP_MPUTOBJI) {
				DUK__LOOKUP_INDIRECT(idx);
			}

			count = (duk_small_uint_fast_t) DUK_DEC_C(ins);
			DUK_ASSERT(count > 0);  /* compiler guarantees */
			idx_end = idx + count;

#if defined(DUK_USE_EXEC_INDIRECT_BOUND_CHECK)
			if (DUK_UNLIKELY(idx_end > (duk_uint_fast_t) duk_get_top(thr))) {
				/* XXX: use duk_is_valid_index() instead? */
				/* XXX: improve check; check against nregs, not against top */
				DUK__INTERNAL_ERROR("MPUTOBJ out of bounds");
			}
#endif

			/* Use 'force' flag to duk_def_prop() to ensure that any
			 * inherited properties don't prevent the operation.
			 * With ES2015 duplicate properties are allowed, so that we
			 * must overwrite any previous data or accessor property.
			 *
			 * With ES2015 computed property names the literal keys
			 * may be arbitrary values and need to be ToPropertyKey()
			 * coerced at runtime.
			 */
			do {
				/* XXX: faster initialization (direct access or better primitives) */
				duk_dup(thr, (duk_idx_t) idx);
				duk_dup(thr, (duk_idx_t) (idx + 1));
				duk_def_prop(thr, obj_idx, DUK_DEFPROP_HAVE_VALUE |
				                           DUK_DEFPROP_FORCE |
				                           DUK_DEFPROP_SET_WRITABLE |
				                           DUK_DEFPROP_SET_ENUMERABLE |
				                           DUK_DEFPROP_SET_CONFIGURABLE);
				idx += 2;
			} while (idx < idx_end);
			break;
		}

		case DUK_OP_INITSET:
		case DUK_OP_INITGET: {
			duk__handle_op_initset_initget(thr, ins);
			break;
		}

		case DUK_OP_MPUTARR:
		case DUK_OP_MPUTARRI: {
			duk_idx_t obj_idx;
			duk_uint_fast_t idx, idx_end;
			duk_small_uint_fast_t count;
			duk_tval *tv1;
			duk_uint32_t arr_idx;

			/* A -> register of target object
			 * B -> first register of value data (start_index, value1, value2, ..., valueN)
			 *      or register containing first register number if indirect
			 * C -> number of key/value pairs (N)
			 */

			obj_idx = DUK_DEC_A(ins);
			DUK_ASSERT(duk_is_object(thr, obj_idx));

			idx = (duk_uint_fast_t) DUK_DEC_B(ins);
			if (DUK_DEC_OP(ins) == DUK_OP_MPUTARRI) {
				DUK__LOOKUP_INDIRECT(idx);
			}

			count = (duk_small_uint_fast_t) DUK_DEC_C(ins);
			DUK_ASSERT(count > 0 + 1);  /* compiler guarantees */
			idx_end = idx + count;

#if defined(DUK_USE_EXEC_INDIRECT_BOUND_CHECK)
			if (idx_end > (duk_uint_fast_t) duk_get_top(thr)) {
				/* XXX: use duk_is_valid_index() instead? */
				/* XXX: improve check; check against nregs, not against top */
				DUK__INTERNAL_ERROR("MPUTARR out of bounds");
			}
#endif

			tv1 = DUK__REGP(idx);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv1));
#if defined(DUK_USE_FASTINT)
			DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv1));
			arr_idx = (duk_uint32_t) DUK_TVAL_GET_FASTINT_U32(tv1);
#else
			arr_idx = (duk_uint32_t) DUK_TVAL_GET_NUMBER(tv1);
#endif
			idx++;

			do {
				/* duk_xdef_prop() will define an own property without any array
				 * special behaviors.  We'll need to set the array length explicitly
				 * in the end.  For arrays with elisions, the compiler will emit an
				 * explicit SETALEN which will update the length.
				 */

				/* XXX: because we're dealing with 'own' properties of a fresh array,
				 * the array initializer should just ensure that the array has a large
				 * enough array part and write the values directly into array part,
				 * and finally set 'length' manually in the end (as already happens now).
				 */

				duk_dup(thr, (duk_idx_t) idx);
				duk_xdef_prop_index_wec(thr, obj_idx, arr_idx);

				idx++;
				arr_idx++;
			} while (idx < idx_end);

			/* XXX: E5.1 Section 11.1.4 coerces the final length through
			 * ToUint32() which is odd but happens now as a side effect of
			 * 'arr_idx' type.
			 */
			duk_set_length(thr, obj_idx, (duk_size_t) (duk_uarridx_t) arr_idx);
			break;
		}

		case DUK_OP_SETALEN: {
			duk_tval *tv1;
			duk_hobject *h;
			duk_uint32_t len;

			tv1 = DUK__REGP_A(ins);
			DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv1));
			h = DUK_TVAL_GET_OBJECT(tv1);
			DUK_ASSERT(DUK_HOBJECT_IS_ARRAY(h));

			tv1 = DUK__REGP_BC(ins);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv1));
#if defined(DUK_USE_FASTINT)
			DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv1));
			len = (duk_uint32_t) DUK_TVAL_GET_FASTINT_U32(tv1);
#else
			len = (duk_uint32_t) DUK_TVAL_GET_NUMBER(tv1);
#endif
			((duk_harray *) h)->length = len;
			break;
		}

		case DUK_OP_INITENUM: {
			duk__handle_op_initenum(thr, ins);
			break;
		}

		case DUK_OP_NEXTENUM: {
			curr_pc += duk__handle_op_nextenum(thr, ins);
			break;
		}

		case DUK_OP_INVLHS: {
			DUK_ERROR_REFERENCE(thr, DUK_STR_INVALID_LVALUE);
			DUK_WO_NORETURN(return;);
			break;
		}

		case DUK_OP_DEBUGGER: {
			/* Opcode only emitted by compiler when debugger
			 * support is enabled.  Ignore it silently without
			 * debugger support, in case it has been loaded
			 * from precompiled bytecode.
			 */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
			if (duk_debug_is_attached(thr->heap)) {
				DUK_D(DUK_DPRINT("DEBUGGER statement encountered, halt execution"));
				DUK__SYNC_AND_NULL_CURR_PC();
				duk_debug_halt_execution(thr, 1 /*use_prev_pc*/);
				DUK_D(DUK_DPRINT("DEBUGGER statement finished, resume execution"));
				goto restart_execution;
			} else {
				DUK_D(DUK_DPRINT("DEBUGGER statement ignored, debugger not attached"));
			}
#else
			DUK_D(DUK_DPRINT("DEBUGGER statement ignored, no debugger support"));
#endif
			break;
		}

		case DUK_OP_NOP: {
			/* Nop, ignored, but ABC fields may carry a value e.g.
			 * for indirect opcode handling.
			 */
			break;
		}

		case DUK_OP_INVALID: {
			DUK_ERROR_FMT1(thr, DUK_ERR_ERROR, "INVALID opcode (%ld)", (long) DUK_DEC_ABC(ins));
			DUK_WO_NORETURN(return;);
			break;
		}

#if defined(DUK_USE_ES6)
		case DUK_OP_NEWTARGET: {
			duk_push_new_target(thr);
			DUK__REPLACE_TOP_BC_BREAK();
		}
#endif  /* DUK_USE_ES6 */

#if !defined(DUK_USE_EXEC_PREFER_SIZE)
#if !defined(DUK_USE_ES7_EXP_OPERATOR)
		case DUK_OP_EXP_RR:
		case DUK_OP_EXP_CR:
		case DUK_OP_EXP_RC:
		case DUK_OP_EXP_CC:
#endif
#if !defined(DUK_USE_ES6)
		case DUK_OP_NEWTARGET:
#endif
#if !defined(DUK_USE_VERBOSE_ERRORS)
		case DUK_OP_GETPROPC_RR:
		case DUK_OP_GETPROPC_CR:
		case DUK_OP_GETPROPC_RC:
		case DUK_OP_GETPROPC_CC:
#endif
		case DUK_OP_UNUSED207:
		case DUK_OP_UNUSED212:
		case DUK_OP_UNUSED213:
		case DUK_OP_UNUSED214:
		case DUK_OP_UNUSED215:
		case DUK_OP_UNUSED216:
		case DUK_OP_UNUSED217:
		case DUK_OP_UNUSED218:
		case DUK_OP_UNUSED219:
		case DUK_OP_UNUSED220:
		case DUK_OP_UNUSED221:
		case DUK_OP_UNUSED222:
		case DUK_OP_UNUSED223:
		case DUK_OP_UNUSED224:
		case DUK_OP_UNUSED225:
		case DUK_OP_UNUSED226:
		case DUK_OP_UNUSED227:
		case DUK_OP_UNUSED228:
		case DUK_OP_UNUSED229:
		case DUK_OP_UNUSED230:
		case DUK_OP_UNUSED231:
		case DUK_OP_UNUSED232:
		case DUK_OP_UNUSED233:
		case DUK_OP_UNUSED234:
		case DUK_OP_UNUSED235:
		case DUK_OP_UNUSED236:
		case DUK_OP_UNUSED237:
		case DUK_OP_UNUSED238:
		case DUK_OP_UNUSED239:
		case DUK_OP_UNUSED240:
		case DUK_OP_UNUSED241:
		case DUK_OP_UNUSED242:
		case DUK_OP_UNUSED243:
		case DUK_OP_UNUSED244:
		case DUK_OP_UNUSED245:
		case DUK_OP_UNUSED246:
		case DUK_OP_UNUSED247:
		case DUK_OP_UNUSED248:
		case DUK_OP_UNUSED249:
		case DUK_OP_UNUSED250:
		case DUK_OP_UNUSED251:
		case DUK_OP_UNUSED252:
		case DUK_OP_UNUSED253:
		case DUK_OP_UNUSED254:
		case DUK_OP_UNUSED255:
		/* Force all case clauses to map to an actual handler
		 * so that the compiler can emit a jump without a bounds
		 * check: the switch argument is a duk_uint8_t so that
		 * the compiler may be able to figure it out.  This is
		 * a small detail and obviously compiler dependent.
		 */
		/* default: clause omitted on purpose */
#else  /* DUK_USE_EXEC_PREFER_SIZE */
		default:
#endif  /* DUK_USE_EXEC_PREFER_SIZE */
		{
			/* Default case catches invalid/unsupported opcodes. */
			DUK_D(DUK_DPRINT("invalid opcode: %ld - %!I", (long) op, ins));
			DUK__INTERNAL_ERROR("invalid opcode");
			break;
		}

		}  /* end switch */

		continue;

		/* Some shared exit paths for opcode handling below.  These
		 * are mostly useful to reduce code footprint when multiple
		 * opcodes have a similar epilogue (like replacing stack top
		 * with index 'a').
		 */

#if defined(DUK_USE_EXEC_PREFER_SIZE)
	 replace_top_a:
		DUK__REPLACE_TO_TVPTR(thr, DUK__REGP_A(ins));
		continue;
	 replace_top_bc:
		DUK__REPLACE_TO_TVPTR(thr, DUK__REGP_BC(ins));
		continue;
#endif
	}
	DUK_WO_NORETURN(return;);

#if !defined(DUK_USE_VERBOSE_EXECUTOR_ERRORS)
 internal_error:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return;);
#endif
}

/* automatic undefs */
#undef DUK__BYTEOFF_A
#undef DUK__BYTEOFF_B
#undef DUK__BYTEOFF_BC
#undef DUK__BYTEOFF_C
#undef DUK__COMPARE_BODY
#undef DUK__CONST
#undef DUK__CONSTP
#undef DUK__CONSTP_A
#undef DUK__CONSTP_B
#undef DUK__CONSTP_BC
#undef DUK__CONSTP_C
#undef DUK__DELPROP_BODY
#undef DUK__EQ_BODY
#undef DUK__FUN
#undef DUK__GETPROPC_BODY
#undef DUK__GETPROP_BODY
#undef DUK__GE_BODY
#undef DUK__GT_BODY
#undef DUK__INSTOF_BODY
#undef DUK__INTERNAL_ERROR
#undef DUK__INT_NOACTION
#undef DUK__INT_RESTART
#undef DUK__IN_BODY
#undef DUK__LE_BODY
#undef DUK__LONGJMP_RESTART
#undef DUK__LONGJMP_RETHROW
#undef DUK__LOOKUP_INDIRECT
#undef DUK__LT_BODY
#undef DUK__MASK_A
#undef DUK__MASK_B
#undef DUK__MASK_BC
#undef DUK__MASK_C
#undef DUK__NEQ_BODY
#undef DUK__PUTPROP_BODY
#undef DUK__RCBIT_B
#undef DUK__RCBIT_C
#undef DUK__REG
#undef DUK__REGCONSTP_B
#undef DUK__REGCONSTP_C
#undef DUK__REGP
#undef DUK__REGP_A
#undef DUK__REGP_B
#undef DUK__REGP_BC
#undef DUK__REGP_C
#undef DUK__REPLACE_BOOL_A_BREAK
#undef DUK__REPLACE_TOP_A_BREAK
#undef DUK__REPLACE_TOP_BC_BREAK
#undef DUK__REPLACE_TO_TVPTR
#undef DUK__RETHAND_FINISHED
#undef DUK__RETHAND_RESTART
#undef DUK__RETURN_SHARED
#undef DUK__SEQ_BODY
#undef DUK__SHIFT_A
#undef DUK__SHIFT_B
#undef DUK__SHIFT_BC
#undef DUK__SHIFT_C
#undef DUK__SNEQ_BODY
#undef DUK__STRICT
#undef DUK__SYNC_AND_NULL_CURR_PC
#undef DUK__SYNC_CURR_PC
#undef DUK__TVAL_SHIFT
/*
 *  ECMAScript specification algorithm and conversion helpers.
 *
 *  These helpers encapsulate the primitive ECMAScript operation semantics,
 *  and are used by the bytecode executor and the API (among other places).
 *  Some primitives are only implemented as part of the API and have no
 *  "internal" helper.  This is the case when an internal helper would not
 *  really be useful; e.g. the operation is rare, uses value stack heavily,
 *  etc.
 *
 *  The operation arguments depend on what is required to implement
 *  the operation:
 *
 *    - If an operation is simple and stateless, and has no side
 *      effects, it won't take an duk_hthread argument and its
 *      arguments may be duk_tval pointers (which are safe as long
 *      as no side effects take place).
 *
 *    - If complex coercions are required (e.g. a "ToNumber" coercion)
 *      or errors may be thrown, the operation takes an duk_hthread
 *      argument.  This also implies that the operation may have
 *      arbitrary side effects, invalidating any duk_tval pointers.
 *
 *    - For operations with potential side effects, arguments can be
 *      taken in several ways:
 *
 *      a) as duk_tval pointers, which makes sense if the "common case"
 *         can be resolved without side effects (e.g. coercion); the
 *         arguments are pushed to the valstack for coercion if
 *         necessary
 *
 *      b) as duk_tval values
 *
 *      c) implicitly on value stack top
 *
 *      d) as indices to the value stack
 *
 *  Future work:
 *
 *     - Argument styles may not be the most sensible in every case now.
 *
 *     - In-place coercions might be useful for several operations, if
 *       in-place coercion is OK for the bytecode executor and the API.
 */

/* #include duk_internal.h -> already included */

/*
 *  ToPrimitive()  (E5 Section 9.1)
 *
 *  ==> implemented in the API.
 */

/*
 *  ToBoolean()  (E5 Section 9.2)
 */

DUK_INTERNAL duk_bool_t duk_js_toboolean(duk_tval *tv) {
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL:
		return 0;
	case DUK_TAG_BOOLEAN:
		DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv) == 0 || DUK_TVAL_GET_BOOLEAN(tv) == 1);
		return DUK_TVAL_GET_BOOLEAN(tv);
	case DUK_TAG_STRING: {
		/* Symbols ToBoolean() coerce to true, regardless of their
		 * description.  This happens with no explicit check because
		 * of the symbol representation byte prefix.
		 */
		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		return (DUK_HSTRING_GET_BYTELEN(h) > 0 ? 1 : 0);
	}
	case DUK_TAG_OBJECT: {
		return 1;
	}
	case DUK_TAG_BUFFER: {
		/* Mimic Uint8Array semantics: objects coerce true, regardless
		 * of buffer length (zero or not) or context.
		 */
		return 1;
	}
	case DUK_TAG_POINTER: {
		void *p = DUK_TVAL_GET_POINTER(tv);
		return (p != NULL ? 1 : 0);
	}
	case DUK_TAG_LIGHTFUNC: {
		return 1;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
		if (DUK_TVAL_GET_FASTINT(tv) != 0) {
			return 1;
		} else {
			return 0;
		}
#endif
	default: {
		/* number */
		duk_double_t d;
#if defined(DUK_USE_PREFER_SIZE)
		int c;
#endif
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
		d = DUK_TVAL_GET_DOUBLE(tv);
#if defined(DUK_USE_PREFER_SIZE)
		c = DUK_FPCLASSIFY((double) d);
		if (c == DUK_FP_ZERO || c == DUK_FP_NAN) {
			return 0;
		} else {
			return 1;
		}
#else
		DUK_ASSERT(duk_double_is_nan_or_zero(d) == 0 || duk_double_is_nan_or_zero(d) == 1);
		return duk_double_is_nan_or_zero(d) ^ 1;
#endif
	}
	}
	DUK_UNREACHABLE();
	DUK_WO_UNREACHABLE(return 0;);
}

/*
 *  ToNumber()  (E5 Section 9.3)
 *
 *  Value to convert must be on stack top, and is popped before exit.
 *
 *  See: http://www.cs.indiana.edu/~burger/FP-Printing-PLDI96.pdf
 *       http://www.cs.indiana.edu/~burger/fp/index.html
 *
 *  Notes on the conversion:
 *
 *    - There are specific requirements on the accuracy of the conversion
 *      through a "Mathematical Value" (MV), so this conversion is not
 *      trivial.
 *
 *    - Quick rejects (e.g. based on first char) are difficult because
 *      the grammar allows leading and trailing white space.
 *
 *    - Quick reject based on string length is difficult even after
 *      accounting for white space; there may be arbitrarily many
 *      decimal digits.
 *
 *    - Standard grammar allows decimal values ("123"), hex values
 *      ("0x123") and infinities
 *
 *    - Unlike source code literals, ToNumber() coerces empty strings
 *      and strings with only whitespace to zero (not NaN).  However,
 *      while '' coerces to 0, '+' and '-' coerce to NaN.
 */

/* E5 Section 9.3.1 */
DUK_LOCAL duk_double_t duk__tonumber_string_raw(duk_hthread *thr) {
	duk_small_uint_t s2n_flags;
	duk_double_t d;

	DUK_ASSERT(duk_is_string(thr, -1));

	/* Quite lenient, e.g. allow empty as zero, but don't allow trailing
	 * garbage.
	 */
	s2n_flags = DUK_S2N_FLAG_TRIM_WHITE |
	            DUK_S2N_FLAG_ALLOW_EXP |
	            DUK_S2N_FLAG_ALLOW_PLUS |
	            DUK_S2N_FLAG_ALLOW_MINUS |
	            DUK_S2N_FLAG_ALLOW_INF |
	            DUK_S2N_FLAG_ALLOW_FRAC |
	            DUK_S2N_FLAG_ALLOW_NAKED_FRAC |
	            DUK_S2N_FLAG_ALLOW_EMPTY_FRAC |
	            DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO |
	            DUK_S2N_FLAG_ALLOW_LEADING_ZERO |
	            DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT |
	            DUK_S2N_FLAG_ALLOW_AUTO_OCT_INT |
	            DUK_S2N_FLAG_ALLOW_AUTO_BIN_INT;

	duk_numconv_parse(thr, 10 /*radix*/, s2n_flags);

#if defined(DUK_USE_PREFER_SIZE)
	d = duk_get_number(thr, -1);
	duk_pop_unsafe(thr);
#else
	thr->valstack_top--;
	DUK_ASSERT(DUK_TVAL_IS_NUMBER(thr->valstack_top));
	DUK_ASSERT(DUK_TVAL_IS_DOUBLE(thr->valstack_top));  /* no fastint conversion in numconv now */
	DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(thr->valstack_top));
	d = DUK_TVAL_GET_DOUBLE(thr->valstack_top);  /* assumes not a fastint */
	DUK_TVAL_SET_UNDEFINED(thr->valstack_top);
#endif

	return d;
}

DUK_INTERNAL duk_double_t duk_js_tonumber(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv != NULL);

	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED: {
		/* return a specific NaN (although not strictly necessary) */
		duk_double_union du;
		DUK_DBLUNION_SET_NAN(&du);
		DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
		return du.d;
	}
	case DUK_TAG_NULL: {
		/* +0.0 */
		return 0.0;
	}
	case DUK_TAG_BOOLEAN: {
		if (DUK_TVAL_IS_BOOLEAN_TRUE(tv)) {
			return 1.0;
		}
		return 0.0;
	}
	case DUK_TAG_STRING: {
		/* For Symbols ToNumber() is always a TypeError. */
		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
			DUK_ERROR_TYPE(thr, DUK_STR_CANNOT_NUMBER_COERCE_SYMBOL);
			DUK_WO_NORETURN(return 0.0;);
		}
		duk_push_hstring(thr, h);
		return duk__tonumber_string_raw(thr);
	}
	case DUK_TAG_BUFFER:  /* plain buffer treated like object */
	case DUK_TAG_OBJECT: {
		duk_double_t d;
		duk_push_tval(thr, tv);
		duk_to_primitive(thr, -1, DUK_HINT_NUMBER);  /* 'tv' becomes invalid */

		/* recursive call for a primitive value (guaranteed not to cause second
		 * recursion).
		 */
		DUK_ASSERT(duk_get_tval(thr, -1) != NULL);
		d = duk_js_tonumber(thr, duk_get_tval(thr, -1));

		duk_pop_unsafe(thr);
		return d;
	}
	case DUK_TAG_POINTER: {
		/* Coerce like boolean */
		void *p = DUK_TVAL_GET_POINTER(tv);
		return (p != NULL ? 1.0 : 0.0);
	}
	case DUK_TAG_LIGHTFUNC: {
		/* +(function(){}) -> NaN */
		return DUK_DOUBLE_NAN;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
		return (duk_double_t) DUK_TVAL_GET_FASTINT(tv);
#endif
	default: {
		/* number */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
		DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
		return DUK_TVAL_GET_DOUBLE(tv);
	}
	}

	DUK_UNREACHABLE();
	DUK_WO_UNREACHABLE(return 0.0;);
}

/*
 *  ToInteger()  (E5 Section 9.4)
 */

/* exposed, used by e.g. duk_bi_date.c */
DUK_INTERNAL duk_double_t duk_js_tointeger_number(duk_double_t x) {
#if defined(DUK_USE_PREFER_SIZE)
	duk_small_int_t c = (duk_small_int_t) DUK_FPCLASSIFY(x);

	if (DUK_UNLIKELY(c == DUK_FP_NAN)) {
		return 0.0;
	} else if (DUK_UNLIKELY(c == DUK_FP_INFINITE)) {
		return x;
	} else {
		/* Finite, including neg/pos zero.  Neg zero sign must be
		 * preserved.
		 */
		return duk_double_trunc_towards_zero(x);
	}
#else  /* DUK_USE_PREFER_SIZE */
	/* NaN and Infinity have the same exponent so it's a cheap
	 * initial check for the rare path.
	 */
	if (DUK_UNLIKELY(duk_double_is_nan_or_inf(x) != 0U)) {
		if (duk_double_is_nan(x)) {
			return 0.0;
		} else {
			return x;
		}
	} else {
		return duk_double_trunc_towards_zero(x);
	}
#endif  /* DUK_USE_PREFER_SIZE */
}

DUK_INTERNAL duk_double_t duk_js_tointeger(duk_hthread *thr, duk_tval *tv) {
	/* XXX: fastint */
	duk_double_t d = duk_js_tonumber(thr, tv);  /* invalidates tv */
	return duk_js_tointeger_number(d);
}

/*
 *  ToInt32(), ToUint32(), ToUint16()  (E5 Sections 9.5, 9.6, 9.7)
 */

/* combined algorithm matching E5 Sections 9.5 and 9.6 */
DUK_LOCAL duk_double_t duk__toint32_touint32_helper(duk_double_t x, duk_bool_t is_toint32) {
#if defined (DUK_USE_PREFER_SIZE)
	duk_small_int_t c;
#endif

#if defined (DUK_USE_PREFER_SIZE)
	c = (duk_small_int_t) DUK_FPCLASSIFY(x);
	if (c == DUK_FP_NAN || c == DUK_FP_ZERO || c == DUK_FP_INFINITE) {
		return 0.0;
	}
#else
	if (duk_double_is_nan_zero_inf(x)) {
		return 0.0;
	}
#endif

	/* x = sign(x) * floor(abs(x)), i.e. truncate towards zero, keep sign */
	x = duk_double_trunc_towards_zero(x);

	/* NOTE: fmod(x) result sign is same as sign of x, which
	 * differs from what Javascript wants (see Section 9.6).
	 */

	x = DUK_FMOD(x, DUK_DOUBLE_2TO32);    /* -> x in ]-2**32, 2**32[ */

	if (x < 0.0) {
		x += DUK_DOUBLE_2TO32;
	}
	DUK_ASSERT(x >= 0 && x < DUK_DOUBLE_2TO32);  /* -> x in [0, 2**32[ */

	if (is_toint32) {
		if (x >= DUK_DOUBLE_2TO31) {
			/* x in [2**31, 2**32[ */

			x -= DUK_DOUBLE_2TO32;  /* -> x in [-2**31,2**31[ */
		}
	}

	return x;
}

DUK_INTERNAL duk_int32_t duk_js_toint32(duk_hthread *thr, duk_tval *tv) {
	duk_double_t d;

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		return DUK_TVAL_GET_FASTINT_I32(tv);
	}
#endif

	d = duk_js_tonumber(thr, tv);  /* invalidates tv */
	d = duk__toint32_touint32_helper(d, 1);
	DUK_ASSERT(DUK_FPCLASSIFY(d) == DUK_FP_ZERO || DUK_FPCLASSIFY(d) == DUK_FP_NORMAL);
	DUK_ASSERT(d >= -2147483648.0 && d <= 2147483647.0);  /* [-0x80000000,0x7fffffff] */
	DUK_ASSERT(duk_double_equals(d, (duk_double_t) ((duk_int32_t) d)));  /* whole, won't clip */
	return (duk_int32_t) d;
}


DUK_INTERNAL duk_uint32_t duk_js_touint32(duk_hthread *thr, duk_tval *tv) {
	duk_double_t d;

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv)) {
		return DUK_TVAL_GET_FASTINT_U32(tv);
	}
#endif

	d = duk_js_tonumber(thr, tv);  /* invalidates tv */
	d = duk__toint32_touint32_helper(d, 0);
	DUK_ASSERT(DUK_FPCLASSIFY(d) == DUK_FP_ZERO || DUK_FPCLASSIFY(d) == DUK_FP_NORMAL);
	DUK_ASSERT(d >= 0.0 && d <= 4294967295.0);  /* [0x00000000, 0xffffffff] */
	DUK_ASSERT(duk_double_equals(d, (duk_double_t) ((duk_uint32_t) d)));  /* whole, won't clip */
	return (duk_uint32_t) d;

}

DUK_INTERNAL duk_uint16_t duk_js_touint16(duk_hthread *thr, duk_tval *tv) {
	/* should be a safe way to compute this */
	return (duk_uint16_t) (duk_js_touint32(thr, tv) & 0x0000ffffU);
}

/*
 *  ToString()  (E5 Section 9.8)
 *  ToObject()  (E5 Section 9.9)
 *  CheckObjectCoercible()  (E5 Section 9.10)
 *  IsCallable()  (E5 Section 9.11)
 *
 *  ==> implemented in the API.
 */

/*
 *  Loose equality, strict equality, and SameValue (E5 Sections 11.9.1, 11.9.4,
 *  9.12).  These have much in common so they can share some helpers.
 *
 *  Future work notes:
 *
 *    - Current implementation (and spec definition) has recursion; this should
 *      be fixed if possible.
 *
 *    - String-to-number coercion should be possible without going through the
 *      value stack (and be more compact) if a shared helper is invoked.
 */

/* Note that this is the same operation for strict and loose equality:
 *  - E5 Section 11.9.3, step 1.c (loose)
 *  - E5 Section 11.9.6, step 4 (strict)
 */

DUK_LOCAL duk_bool_t duk__js_equals_number(duk_double_t x, duk_double_t y) {
#if defined(DUK_USE_PARANOID_MATH)
	/* Straightforward algorithm, makes fewer compiler assumptions. */
	duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
	duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);
	if (cx == DUK_FP_NAN || cy == DUK_FP_NAN) {
		return 0;
	}
	if (cx == DUK_FP_ZERO && cy == DUK_FP_ZERO) {
		return 1;
	}
	if (x == y) {
		return 1;
	}
	return 0;
#else  /* DUK_USE_PARANOID_MATH */
	/* Better equivalent algorithm.  If the compiler is compliant, C and
	 * ECMAScript semantics are identical for this particular comparison.
	 * In particular, NaNs must never compare equal and zeroes must compare
	 * equal regardless of sign.  Could also use a macro, but this inlines
	 * already nicely (no difference on gcc, for instance).
	 */
	if (duk_double_equals(x, y)) {
		/* IEEE requires that NaNs compare false */
		DUK_ASSERT(DUK_FPCLASSIFY(x) != DUK_FP_NAN);
		DUK_ASSERT(DUK_FPCLASSIFY(y) != DUK_FP_NAN);
		return 1;
	} else {
		/* IEEE requires that zeros compare the same regardless
		 * of their signed, so if both x and y are zeroes, they
		 * are caught above.
		 */
		DUK_ASSERT(!(DUK_FPCLASSIFY(x) == DUK_FP_ZERO && DUK_FPCLASSIFY(y) == DUK_FP_ZERO));
		return 0;
	}
#endif  /* DUK_USE_PARANOID_MATH */
}

DUK_LOCAL duk_bool_t duk__js_samevalue_number(duk_double_t x, duk_double_t y) {
#if defined(DUK_USE_PARANOID_MATH)
	duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
	duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);

	if (cx == DUK_FP_NAN && cy == DUK_FP_NAN) {
		/* SameValue(NaN, NaN) = true, regardless of NaN sign or extra bits */
		return 1;
	}
	if (cx == DUK_FP_ZERO && cy == DUK_FP_ZERO) {
		/* Note: cannot assume that a non-zero return value of signbit() would
		 * always be the same -- hence cannot (portably) use something like:
		 *
		 *     signbit(x) == signbit(y)
		 */
		duk_small_int_t sx = DUK_SIGNBIT(x) ? 1 : 0;
		duk_small_int_t sy = DUK_SIGNBIT(y) ? 1 : 0;
		return (sx == sy);
	}

	/* normal comparison; known:
	 *   - both x and y are not NaNs (but one of them can be)
	 *   - both x and y are not zero (but one of them can be)
	 *   - x and y may be denormal or infinite
	 */

	return (x == y);
#else  /* DUK_USE_PARANOID_MATH */
	duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
	duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);

	if (duk_double_equals(x, y)) {
		/* IEEE requires that NaNs compare false */
		DUK_ASSERT(DUK_FPCLASSIFY(x) != DUK_FP_NAN);
		DUK_ASSERT(DUK_FPCLASSIFY(y) != DUK_FP_NAN);

		/* Using classification has smaller footprint than direct comparison. */
		if (DUK_UNLIKELY(cx == DUK_FP_ZERO && cy == DUK_FP_ZERO)) {
			/* Note: cannot assume that a non-zero return value of signbit() would
			 * always be the same -- hence cannot (portably) use something like:
			 *
			 *     signbit(x) == signbit(y)
			 */
			return duk_double_same_sign(x, y);
		}
		return 1;
	} else {
		/* IEEE requires that zeros compare the same regardless
		 * of their sign, so if both x and y are zeroes, they
		 * are caught above.
		 */
		DUK_ASSERT(!(DUK_FPCLASSIFY(x) == DUK_FP_ZERO && DUK_FPCLASSIFY(y) == DUK_FP_ZERO));

		/* Difference to non-strict/strict comparison is that NaNs compare
		 * equal and signed zero signs matter.
		 */
		if (DUK_UNLIKELY(cx == DUK_FP_NAN && cy == DUK_FP_NAN)) {
			/* SameValue(NaN, NaN) = true, regardless of NaN sign or extra bits */
			return 1;
		}
		return 0;
	}
#endif  /* DUK_USE_PARANOID_MATH */
}

DUK_INTERNAL duk_bool_t duk_js_equals_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags) {
	duk_uint_t type_mask_x;
	duk_uint_t type_mask_y;

	/* If flags != 0 (strict or SameValue), thr can be NULL.  For loose
	 * equals comparison it must be != NULL.
	 */
	DUK_ASSERT(flags != 0 || thr != NULL);

	/*
	 *  Same type?
	 *
	 *  Note: since number values have no explicit tag in the 8-byte
	 *  representation, need the awkward if + switch.
	 */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
		if (DUK_TVAL_GET_FASTINT(tv_x) == DUK_TVAL_GET_FASTINT(tv_y)) {
			return 1;
		} else {
			return 0;
		}
	}
	else
#endif
	if (DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y)) {
		duk_double_t d1, d2;

		/* Catches both doubles and cases where only one argument is
		 * a fastint so can't assume a double.
		 */
		d1 = DUK_TVAL_GET_NUMBER(tv_x);
		d2 = DUK_TVAL_GET_NUMBER(tv_y);
		if (DUK_UNLIKELY((flags & DUK_EQUALS_FLAG_SAMEVALUE) != 0)) {
			/* SameValue */
			return duk__js_samevalue_number(d1, d2);
		} else {
			/* equals and strict equals */
			return duk__js_equals_number(d1, d2);
		}
	} else if (DUK_TVAL_GET_TAG(tv_x) == DUK_TVAL_GET_TAG(tv_y)) {
		switch (DUK_TVAL_GET_TAG(tv_x)) {
		case DUK_TAG_UNDEFINED:
		case DUK_TAG_NULL: {
			return 1;
		}
		case DUK_TAG_BOOLEAN: {
			return DUK_TVAL_GET_BOOLEAN(tv_x) == DUK_TVAL_GET_BOOLEAN(tv_y);
		}
		case DUK_TAG_POINTER: {
			return DUK_TVAL_GET_POINTER(tv_x) == DUK_TVAL_GET_POINTER(tv_y);
		}
		case DUK_TAG_STRING:
		case DUK_TAG_OBJECT: {
			/* Heap pointer comparison suffices for strings and objects.
			 * Symbols compare equal if they have the same internal
			 * representation; again heap pointer comparison suffices.
			 */
			return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
		}
		case DUK_TAG_BUFFER: {
			/* In Duktape 2.x plain buffers mimic Uint8Array objects
			 * so always compare by heap pointer.  In Duktape 1.x
			 * strict comparison would compare heap pointers and
			 * non-strict would compare contents.
			 */
			return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
		}
		case DUK_TAG_LIGHTFUNC: {
			/* At least 'magic' has a significant impact on function
			 * identity.
			 */
			duk_small_uint_t lf_flags_x;
			duk_small_uint_t lf_flags_y;
			duk_c_function func_x;
			duk_c_function func_y;

			DUK_TVAL_GET_LIGHTFUNC(tv_x, func_x, lf_flags_x);
			DUK_TVAL_GET_LIGHTFUNC(tv_y, func_y, lf_flags_y);
			return ((func_x == func_y) && (lf_flags_x == lf_flags_y)) ? 1 : 0;
		}
#if defined(DUK_USE_FASTINT)
		case DUK_TAG_FASTINT:
#endif
		default: {
			DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_x));
			DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_y));
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_y));
			DUK_UNREACHABLE();
			DUK_WO_UNREACHABLE(return 0;);
		}
		}
	}

	if ((flags & (DUK_EQUALS_FLAG_STRICT | DUK_EQUALS_FLAG_SAMEVALUE)) != 0) {
		return 0;
	}

	DUK_ASSERT(flags == 0);  /* non-strict equality from here on */

	/*
	 *  Types are different; various cases for non-strict comparison
	 *
	 *  Since comparison is symmetric, we use a "swap trick" to reduce
	 *  code size.
	 */

	type_mask_x = duk_get_type_mask_tval(tv_x);
	type_mask_y = duk_get_type_mask_tval(tv_y);

	/* Undefined/null are considered equal (e.g. "null == undefined" -> true). */
	if ((type_mask_x & (DUK_TYPE_MASK_UNDEFINED | DUK_TYPE_MASK_NULL)) &&
	    (type_mask_y & (DUK_TYPE_MASK_NULL | DUK_TYPE_MASK_UNDEFINED))) {
		return 1;
	}

	/* Number/string -> coerce string to number (e.g. "'1.5' == 1.5" -> true). */
	if ((type_mask_x & DUK_TYPE_MASK_NUMBER) && (type_mask_y & DUK_TYPE_MASK_STRING)) {
		if (!DUK_TVAL_STRING_IS_SYMBOL(tv_y)) {
			duk_double_t d1, d2;
			d1 = DUK_TVAL_GET_NUMBER(tv_x);
			d2 = duk_to_number_tval(thr, tv_y);
			return duk__js_equals_number(d1, d2);
		}
	}
	if ((type_mask_x & DUK_TYPE_MASK_STRING) && (type_mask_y & DUK_TYPE_MASK_NUMBER)) {
		if (!DUK_TVAL_STRING_IS_SYMBOL(tv_x)) {
			duk_double_t d1, d2;
			d1 = DUK_TVAL_GET_NUMBER(tv_y);
			d2 = duk_to_number_tval(thr, tv_x);
			return duk__js_equals_number(d1, d2);
		}
	}

	/* Boolean/any -> coerce boolean to number and try again.  If boolean is
	 * compared to a pointer, the final comparison after coercion now always
	 * yields false (as pointer vs. number compares to false), but this is
	 * not special cased.
	 *
	 * ToNumber(bool) is +1.0 or 0.0.  Tagged boolean value is always 0 or 1.
	 */
	if (type_mask_x & DUK_TYPE_MASK_BOOLEAN) {
		DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv_x) == 0 || DUK_TVAL_GET_BOOLEAN(tv_x) == 1);
		duk_push_uint(thr, DUK_TVAL_GET_BOOLEAN(tv_x));
		duk_push_tval(thr, tv_y);
		goto recursive_call;
	}
	if (type_mask_y & DUK_TYPE_MASK_BOOLEAN) {
		DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv_y) == 0 || DUK_TVAL_GET_BOOLEAN(tv_y) == 1);
		duk_push_tval(thr, tv_x);
		duk_push_uint(thr, DUK_TVAL_GET_BOOLEAN(tv_y));
		goto recursive_call;
	}

	/* String-number-symbol/object -> coerce object to primitive (apparently without hint), then try again. */
	if ((type_mask_x & (DUK_TYPE_MASK_STRING | DUK_TYPE_MASK_NUMBER)) &&
	    (type_mask_y & DUK_TYPE_MASK_OBJECT)) {
		/* No symbol check needed because symbols and strings are accepted. */
		duk_push_tval(thr, tv_x);
		duk_push_tval(thr, tv_y);
		duk_to_primitive(thr, -1, DUK_HINT_NONE);  /* apparently no hint? */
		goto recursive_call;
	}
	if ((type_mask_x & DUK_TYPE_MASK_OBJECT) &&
	    (type_mask_y & (DUK_TYPE_MASK_STRING | DUK_TYPE_MASK_NUMBER))) {
		/* No symbol check needed because symbols and strings are accepted. */
		duk_push_tval(thr, tv_x);
		duk_push_tval(thr, tv_y);
		duk_to_primitive(thr, -2, DUK_HINT_NONE);  /* apparently no hint? */
		goto recursive_call;
	}

	/* Nothing worked -> not equal. */
	return 0;

 recursive_call:
	/* Shared code path to call the helper again with arguments on stack top. */
	{
		duk_bool_t rc;
		rc = duk_js_equals_helper(thr,
		                          DUK_GET_TVAL_NEGIDX(thr, -2),
		                          DUK_GET_TVAL_NEGIDX(thr, -1),
		                          0 /*flags:nonstrict*/);
		duk_pop_2_unsafe(thr);
		return rc;
	}
}

/*
 *  Comparisons (x >= y, x > y, x <= y, x < y)
 *
 *  E5 Section 11.8.5: implement 'x < y' and then use negate and eval_left_first
 *  flags to get the rest.
 */

/* XXX: this should probably just operate on the stack top, because it
 * needs to push stuff on the stack anyway...
 */

DUK_INTERNAL duk_small_int_t duk_js_data_compare(const duk_uint8_t *buf1, const duk_uint8_t *buf2, duk_size_t len1, duk_size_t len2) {
	duk_size_t prefix_len;
	duk_small_int_t rc;

	prefix_len = (len1 <= len2 ? len1 : len2);

	/* duk_memcmp() is guaranteed to return zero (equal) for zero length
	 * inputs.
	 */
	rc = duk_memcmp_unsafe((const void *) buf1,
	                       (const void *) buf2,
	                       (size_t) prefix_len);

	if (rc < 0) {
		return -1;
	} else if (rc > 0) {
		return 1;
	}

	/* prefix matches, lengths matter now */
	if (len1 < len2) {
		/* e.g. "x" < "xx" */
		return -1;
	} else if (len1 > len2) {
		return 1;
	}

	return 0;
}

DUK_INTERNAL duk_small_int_t duk_js_string_compare(duk_hstring *h1, duk_hstring *h2) {
	/*
	 *  String comparison (E5 Section 11.8.5, step 4), which
	 *  needs to compare codepoint by codepoint.
	 *
	 *  However, UTF-8 allows us to use strcmp directly: the shared
	 *  prefix will be encoded identically (UTF-8 has unique encoding)
	 *  and the first differing character can be compared with a simple
	 *  unsigned byte comparison (which strcmp does).
	 *
	 *  This will not work properly for non-xutf-8 strings, but this
	 *  is not an issue for compliance.
	 */

	DUK_ASSERT(h1 != NULL);
	DUK_ASSERT(h2 != NULL);

	return duk_js_data_compare((const duk_uint8_t *) DUK_HSTRING_GET_DATA(h1),
	                           (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h2),
	                           (duk_size_t) DUK_HSTRING_GET_BYTELEN(h1),
	                           (duk_size_t) DUK_HSTRING_GET_BYTELEN(h2));
}

#if 0  /* unused */
DUK_INTERNAL duk_small_int_t duk_js_buffer_compare(duk_heap *heap, duk_hbuffer *h1, duk_hbuffer *h2) {
	/* Similar to String comparison. */

	DUK_ASSERT(h1 != NULL);
	DUK_ASSERT(h2 != NULL);
	DUK_UNREF(heap);

	return duk_js_data_compare((const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(heap, h1),
	                           (const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(heap, h2),
	                           (duk_size_t) DUK_HBUFFER_GET_SIZE(h1),
	                           (duk_size_t) DUK_HBUFFER_GET_SIZE(h2));
}
#endif

#if defined(DUK_USE_FASTINT)
DUK_LOCAL duk_bool_t duk__compare_fastint(duk_bool_t retval, duk_int64_t v1, duk_int64_t v2) {
	DUK_ASSERT(retval == 0 || retval == 1);
	if (v1 < v2) {
		return retval ^ 1;
	} else {
		return retval;
	}
}
#endif

#if defined(DUK_USE_PARANOID_MATH)
DUK_LOCAL duk_bool_t duk__compare_number(duk_bool_t retval, duk_double_t d1, duk_double_t d2) {
	duk_small_int_t c1, s1, c2, s2;

	DUK_ASSERT(retval == 0 || retval == 1);
	c1 = (duk_small_int_t) DUK_FPCLASSIFY(d1);
	s1 = (duk_small_int_t) DUK_SIGNBIT(d1);
	c2 = (duk_small_int_t) DUK_FPCLASSIFY(d2);
	s2 = (duk_small_int_t) DUK_SIGNBIT(d2);

	if (c1 == DUK_FP_NAN || c2 == DUK_FP_NAN) {
		return 0;  /* Always false, regardless of negation. */
	}

	if (c1 == DUK_FP_ZERO && c2 == DUK_FP_ZERO) {
		/* For all combinations: +0 < +0, +0 < -0, -0 < +0, -0 < -0,
		 * steps e, f, and g.
		 */
		return retval;  /* false */
	}

	if (d1 == d2) {
		return retval;  /* false */
	}

	if (c1 == DUK_FP_INFINITE && s1 == 0) {
		/* x == +Infinity */
		return retval;  /* false */
	}

	if (c2 == DUK_FP_INFINITE && s2 == 0) {
		/* y == +Infinity */
		return retval ^ 1;  /* true */
	}

	if (c2 == DUK_FP_INFINITE && s2 != 0) {
		/* y == -Infinity */
		return retval;  /* false */
	}

	if (c1 == DUK_FP_INFINITE && s1 != 0) {
		/* x == -Infinity */
		return retval ^ 1;  /* true */
	}

	if (d1 < d2) {
		return retval ^ 1;  /* true */
	}

	return retval;  /* false */
}
#else  /* DUK_USE_PARANOID_MATH */
DUK_LOCAL duk_bool_t duk__compare_number(duk_bool_t retval, duk_double_t d1, duk_double_t d2) {
	/* This comparison tree relies doesn't match the exact steps in
	 * E5 Section 11.8.5 but should produce the same results.  The
	 * steps rely on exact IEEE semantics for NaNs, etc.
	 */

	DUK_ASSERT(retval == 0 || retval == 1);
	if (d1 < d2) {
		/* In no case should both (d1 < d2) and (d2 < d1) be true.
		 * It's possible that neither is true though, and that's
		 * handled below.
		 */
		DUK_ASSERT(!(d2 < d1));

		/* - d1 < d2, both d1/d2 are normals (not Infinity, not NaN)
		 * - d2 is +Infinity, d1 != +Infinity and NaN
		 * - d1 is -Infinity, d2 != -Infinity and NaN
		 */
		return retval ^ 1;
	} else {
		if (d2 < d1) {
			/* - !(d1 < d2), both d1/d2 are normals (not Infinity, not NaN)
			 * - d1 is +Infinity, d2 != +Infinity and NaN
			 * - d2 is -Infinity, d1 != -Infinity and NaN
			 */
			return retval;
		} else {
			/* - d1 and/or d2 is NaN
			 * - d1 and d2 are both +/- 0
			 * - d1 == d2 (including infinities)
			 */
			if (duk_double_is_nan(d1) || duk_double_is_nan(d2)) {
				/* Note: undefined from Section 11.8.5 always
				 * results in false return (see e.g. Section
				 * 11.8.3) - hence special treatment here.
				 */
				return 0;  /* zero regardless of negation */
			} else {
				return retval;
			}
		}
	}
}
#endif  /* DUK_USE_PARANOID_MATH */

DUK_INTERNAL duk_bool_t duk_js_compare_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags) {
	duk_double_t d1, d2;
	duk_small_int_t rc;
	duk_bool_t retval;

	DUK_ASSERT(DUK_COMPARE_FLAG_NEGATE == 1);  /* Rely on this flag being lowest. */
	retval = flags & DUK_COMPARE_FLAG_NEGATE;
	DUK_ASSERT(retval == 0 || retval == 1);

	/* Fast path for fastints */
#if defined(DUK_USE_FASTINT)
	if (DUK_LIKELY(DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y))) {
		return duk__compare_fastint(retval,
		                            DUK_TVAL_GET_FASTINT(tv_x),
		                            DUK_TVAL_GET_FASTINT(tv_y));
	}
#endif  /* DUK_USE_FASTINT */

	/* Fast path for numbers (one of which may be a fastint) */
#if !defined(DUK_USE_PREFER_SIZE)
	if (DUK_LIKELY(DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y))) {
		return duk__compare_number(retval,
		                           DUK_TVAL_GET_NUMBER(tv_x),
		                           DUK_TVAL_GET_NUMBER(tv_y));
	}
#endif

	/* Slow path */

	duk_push_tval(thr, tv_x);
	duk_push_tval(thr, tv_y);

	if (flags & DUK_COMPARE_FLAG_EVAL_LEFT_FIRST) {
		duk_to_primitive(thr, -2, DUK_HINT_NUMBER);
		duk_to_primitive(thr, -1, DUK_HINT_NUMBER);
	} else {
		duk_to_primitive(thr, -1, DUK_HINT_NUMBER);
		duk_to_primitive(thr, -2, DUK_HINT_NUMBER);
	}

	/* Note: reuse variables */
	tv_x = DUK_GET_TVAL_NEGIDX(thr, -2);
	tv_y = DUK_GET_TVAL_NEGIDX(thr, -1);

	if (DUK_TVAL_IS_STRING(tv_x) && DUK_TVAL_IS_STRING(tv_y)) {
		duk_hstring *h1 = DUK_TVAL_GET_STRING(tv_x);
		duk_hstring *h2 = DUK_TVAL_GET_STRING(tv_y);
		DUK_ASSERT(h1 != NULL);
		DUK_ASSERT(h2 != NULL);

		if (DUK_LIKELY(!DUK_HSTRING_HAS_SYMBOL(h1) && !DUK_HSTRING_HAS_SYMBOL(h2))) {
			rc = duk_js_string_compare(h1, h2);
			duk_pop_2_unsafe(thr);
			if (rc < 0) {
				return retval ^ 1;
			} else {
				return retval;
			}
		}

		/* One or both are Symbols: fall through to handle in the
		 * generic path.  Concretely, ToNumber() will fail.
		 */
	}

	/* Ordering should not matter (E5 Section 11.8.5, step 3.a). */
#if 0
	if (flags & DUK_COMPARE_FLAG_EVAL_LEFT_FIRST) {
		d1 = duk_to_number_m2(thr);
		d2 = duk_to_number_m1(thr);
	} else {
		d2 = duk_to_number_m1(thr);
		d1 = duk_to_number_m2(thr);
	}
#endif
	d1 = duk_to_number_m2(thr);
	d2 = duk_to_number_m1(thr);

	/* We want to duk_pop_2_unsafe(thr); because the values are numbers
	 * no decref check is needed.
	 */
#if defined(DUK_USE_PREFER_SIZE)
	duk_pop_2_nodecref_unsafe(thr);
#else
	DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk_get_tval(thr, -2)));
	DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk_get_tval(thr, -1)));
	DUK_ASSERT(duk_get_top(thr) >= 2);
	thr->valstack_top -= 2;
	tv_x = thr->valstack_top;
	tv_y = tv_x + 1;
	DUK_TVAL_SET_UNDEFINED(tv_x);  /* Value stack policy */
	DUK_TVAL_SET_UNDEFINED(tv_y);
#endif

	return duk__compare_number(retval, d1, d2);
}

/*
 *  instanceof
 */

/*
 *  ES2015 Section 7.3.19 describes the OrdinaryHasInstance() algorithm
 *  which covers both bound and non-bound functions; in effect the algorithm
 *  includes E5 Sections 11.8.6, 15.3.5.3, and 15.3.4.5.3.
 *
 *  ES2015 Section 12.9.4 describes the instanceof operator which first
 *  checks @@hasInstance well-known symbol and falls back to
 *  OrdinaryHasInstance().
 *
 *  Limited Proxy support: don't support 'getPrototypeOf' trap but
 *  continue lookup in Proxy target if the value is a Proxy.
 */

DUK_LOCAL duk_bool_t duk__js_instanceof_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_bool_t skip_sym_check) {
	duk_hobject *func;
	duk_hobject *val;
	duk_hobject *proto;
	duk_tval *tv;
	duk_bool_t skip_first;
	duk_uint_t sanity;

	/*
	 *  Get the values onto the stack first.  It would be possible to cover
	 *  some normal cases without resorting to the value stack.
	 *
	 *  The right hand side could be a light function (as they generally
	 *  behave like objects).  Light functions never have a 'prototype'
	 *  property so E5.1 Section 15.3.5.3 step 3 always throws a TypeError.
	 *  Using duk_require_hobject() is thus correct (except for error msg).
	 */

	duk_push_tval(thr, tv_x);
	duk_push_tval(thr, tv_y);
	func = duk_require_hobject(thr, -1);
	DUK_ASSERT(func != NULL);

#if defined(DUK_USE_SYMBOL_BUILTIN)
	/*
	 *  @@hasInstance check, ES2015 Section 12.9.4, Steps 2-4.
	 */
	if (!skip_sym_check) {
		if (duk_get_method_stridx(thr, -1, DUK_STRIDX_WELLKNOWN_SYMBOL_HAS_INSTANCE)) {
			/* [ ... lhs rhs func ] */
			duk_insert(thr, -3);    /* -> [ ... func lhs rhs ] */
			duk_swap_top(thr, -2);  /* -> [ ... func rhs(this) lhs ] */
			duk_call_method(thr, 1);
			return duk_to_boolean_top_pop(thr);
		}
	}
#else
	DUK_UNREF(skip_sym_check);
#endif

	/*
	 *  For bound objects, [[HasInstance]] just calls the target function
	 *  [[HasInstance]].  If that is again a bound object, repeat until
	 *  we find a non-bound Function object.
	 *
	 *  The bound function chain is now "collapsed" so there can be only
	 *  one bound function in the chain.
	 */

	if (!DUK_HOBJECT_IS_CALLABLE(func)) {
		/*
		 *  Note: of native ECMAScript objects, only Function instances
		 *  have a [[HasInstance]] internal property.  Custom objects might
		 *  also have it, but not in current implementation.
		 *
		 *  XXX: add a separate flag, DUK_HOBJECT_FLAG_ALLOW_INSTANCEOF?
		 */
		goto error_invalid_rval;
	}

	if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
		duk_push_tval(thr, &((duk_hboundfunc *) (void *) func)->target);
		duk_replace(thr, -2);
		func = duk_require_hobject(thr, -1);  /* lightfunc throws */

		/* Rely on Function.prototype.bind() never creating bound
		 * functions whose target is not proper.
		 */
		DUK_ASSERT(func != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(func));
	}

	/*
	 *  'func' is now a non-bound object which supports [[HasInstance]]
	 *  (which here just means DUK_HOBJECT_FLAG_CALLABLE).  Move on
	 *  to execute E5 Section 15.3.5.3.
	 */

	DUK_ASSERT(func != NULL);
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
	DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(func));

	/* [ ... lval rval(func) ] */

	/* For lightfuncs, buffers, and pointers start the comparison directly
	 * from the virtual prototype object.
	 */
	skip_first = 0;
	tv = DUK_GET_TVAL_NEGIDX(thr, -2);
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_LIGHTFUNC:
		val = thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE];
		DUK_ASSERT(val != NULL);
		break;
	case DUK_TAG_BUFFER:
		val = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
		DUK_ASSERT(val != NULL);
		break;
	case DUK_TAG_POINTER:
		val = thr->builtins[DUK_BIDX_POINTER_PROTOTYPE];
		DUK_ASSERT(val != NULL);
		break;
	case DUK_TAG_OBJECT:
		skip_first = 1;  /* Ignore object itself on first round. */
		val = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(val != NULL);
		break;
	default:
		goto pop2_and_false;
	}
	DUK_ASSERT(val != NULL);  /* Loop doesn't actually rely on this. */

	/* Look up .prototype of rval.  Leave it on the value stack in case it
	 * has been virtualized (e.g. getter, Proxy trap).
	 */
	duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_PROTOTYPE);  /* -> [ ... lval rval rval.prototype ] */
#if defined(DUK_USE_VERBOSE_ERRORS)
	proto = duk_get_hobject(thr, -1);
	if (proto == NULL) {
		goto error_invalid_rval_noproto;
	}
#else
	proto = duk_require_hobject(thr, -1);
#endif

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	do {
		/*
		 *  Note: prototype chain is followed BEFORE first comparison.  This
		 *  means that the instanceof lval is never itself compared to the
		 *  rval.prototype property.  This is apparently intentional, see E5
		 *  Section 15.3.5.3, step 4.a.
		 *
		 *  Also note:
		 *
		 *      js> (function() {}) instanceof Function
		 *      true
		 *      js> Function instanceof Function
		 *      true
		 *
		 *  For the latter, h_proto will be Function.prototype, which is the
		 *  built-in Function prototype.  Because Function.[[Prototype]] is
		 *  also the built-in Function prototype, the result is true.
		 */

		if (!val) {
			goto pop3_and_false;
		}

		DUK_ASSERT(val != NULL);
#if defined(DUK_USE_ES6_PROXY)
		val = duk_hobject_resolve_proxy_target(val);
#endif

		if (skip_first) {
			skip_first = 0;
		} else if (val == proto) {
			goto pop3_and_true;
		}

		DUK_ASSERT(val != NULL);
		val = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, val);
	} while (--sanity > 0);

	DUK_ASSERT(sanity == 0);
	DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
	DUK_WO_NORETURN(return 0;);

 pop2_and_false:
	duk_pop_2_unsafe(thr);
	return 0;

 pop3_and_false:
	duk_pop_3_unsafe(thr);
	return 0;

 pop3_and_true:
	duk_pop_3_unsafe(thr);
	return 1;

 error_invalid_rval:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_INSTANCEOF_RVAL);
	DUK_WO_NORETURN(return 0;);

#if defined(DUK_USE_VERBOSE_ERRORS)
 error_invalid_rval_noproto:
	DUK_ERROR_TYPE(thr, DUK_STR_INVALID_INSTANCEOF_RVAL_NOPROTO);
	DUK_WO_NORETURN(return 0;);
#endif
}

#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL duk_bool_t duk_js_instanceof_ordinary(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
	return duk__js_instanceof_helper(thr, tv_x, tv_y, 1 /*skip_sym_check*/);
}
#endif

DUK_INTERNAL duk_bool_t duk_js_instanceof(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
	return duk__js_instanceof_helper(thr, tv_x, tv_y, 0 /*skip_sym_check*/);
}

/*
 *  in
 */

/*
 *  E5 Sections 11.8.7, 8.12.6.
 *
 *  Basically just a property existence check using [[HasProperty]].
 */

DUK_INTERNAL duk_bool_t duk_js_in(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
	duk_bool_t retval;

	/*
	 *  Get the values onto the stack first.  It would be possible to cover
	 *  some normal cases without resorting to the value stack (e.g. if
	 *  lval is already a string).
	 */

	/* XXX: The ES5/5.1/6 specifications require that the key in 'key in obj'
	 * must be string coerced before the internal HasProperty() algorithm is
	 * invoked.  A fast path skipping coercion could be safely implemented for
	 * numbers (as number-to-string coercion has no side effects).  For ES2015
	 * proxy behavior, the trap 'key' argument must be in a string coerced
	 * form (which is a shame).
	 */

	/* TypeError if rval is not an object or object like (e.g. lightfunc
	 * or plain buffer).
	 */
	duk_push_tval(thr, tv_x);
	duk_push_tval(thr, tv_y);
	duk_require_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT | DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);

	(void) duk_to_property_key_hstring(thr, -2);

	retval = duk_hobject_hasprop(thr,
	                             DUK_GET_TVAL_NEGIDX(thr, -1),
	                             DUK_GET_TVAL_NEGIDX(thr, -2));

	duk_pop_2_unsafe(thr);
	return retval;
}

/*
 *  typeof
 *
 *  E5 Section 11.4.3.
 *
 *  Very straightforward.  The only question is what to return for our
 *  non-standard tag / object types.
 *
 *  There is an unfortunate string constant define naming problem with
 *  typeof return values for e.g. "Object" and "object"; careful with
 *  the built-in string defines.  The LC_XXX defines are used for the
 *  lowercase variants now.
 */

DUK_INTERNAL duk_small_uint_t duk_js_typeof_stridx(duk_tval *tv_x) {
	duk_small_uint_t stridx = 0;

	switch (DUK_TVAL_GET_TAG(tv_x)) {
	case DUK_TAG_UNDEFINED: {
		stridx = DUK_STRIDX_LC_UNDEFINED;
		break;
	}
	case DUK_TAG_NULL: {
		/* Note: not a typo, "object" is returned for a null value. */
		stridx = DUK_STRIDX_LC_OBJECT;
		break;
	}
	case DUK_TAG_BOOLEAN: {
		stridx = DUK_STRIDX_LC_BOOLEAN;
		break;
	}
	case DUK_TAG_POINTER: {
		/* Implementation specific. */
		stridx = DUK_STRIDX_LC_POINTER;
		break;
	}
	case DUK_TAG_STRING: {
		duk_hstring *str;

		/* All internal keys are identified as Symbols. */
		str = DUK_TVAL_GET_STRING(tv_x);
		DUK_ASSERT(str != NULL);
		if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(str))) {
			stridx = DUK_STRIDX_LC_SYMBOL;
		} else {
			stridx = DUK_STRIDX_LC_STRING;
		}
		break;
	}
	case DUK_TAG_OBJECT: {
		duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv_x);
		DUK_ASSERT(obj != NULL);
		if (DUK_HOBJECT_IS_CALLABLE(obj)) {
			stridx = DUK_STRIDX_LC_FUNCTION;
		} else {
			stridx = DUK_STRIDX_LC_OBJECT;
		}
		break;
	}
	case DUK_TAG_BUFFER: {
		/* Implementation specific.  In Duktape 1.x this would be
		 * 'buffer', in Duktape 2.x changed to 'object' because plain
		 * buffers now mimic Uint8Array objects.
		 */
		stridx = DUK_STRIDX_LC_OBJECT;
		break;
	}
	case DUK_TAG_LIGHTFUNC: {
		stridx = DUK_STRIDX_LC_FUNCTION;
		break;
	}
#if defined(DUK_USE_FASTINT)
	case DUK_TAG_FASTINT:
#endif
	default: {
		/* number */
		DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_x));
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
		stridx = DUK_STRIDX_LC_NUMBER;
		break;
	}
	}

	DUK_ASSERT_STRIDX_VALID(stridx);
	return stridx;
}

/*
 *  IsArray()
 */

DUK_INTERNAL duk_bool_t duk_js_isarray_hobject(duk_hobject *h) {
	DUK_ASSERT(h != NULL);
#if defined(DUK_USE_ES6_PROXY)
	h = duk_hobject_resolve_proxy_target(h);
#endif
	return (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_ARRAY ? 1 : 0);
}

DUK_INTERNAL duk_bool_t duk_js_isarray(duk_tval *tv) {
	DUK_ASSERT(tv != NULL);
	if (DUK_TVAL_IS_OBJECT(tv)) {
		return duk_js_isarray_hobject(DUK_TVAL_GET_OBJECT(tv));
	}
	return 0;
}

/*
 *  Array index and length
 *
 *  Array index: E5 Section 15.4
 *  Array length: E5 Section 15.4.5.1 steps 3.c - 3.d (array length write)
 */

/* Compure array index from string context, or return a "not array index"
 * indicator.
 */
DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_string(const duk_uint8_t *str, duk_uint32_t blen) {
	duk_uarridx_t res;

	/* Only strings with byte length 1-10 can be 32-bit array indices.
	 * Leading zeroes (except '0' alone), plus/minus signs are not allowed.
	 * We could do a lot of prechecks here, but since most strings won't
	 * start with any digits, it's simpler to just parse the number and
	 * fail quickly.
	 */

	res = 0;
	if (blen == 0) {
		goto parse_fail;
	}
	do {
		duk_uarridx_t dig;
		dig = (duk_uarridx_t) (*str++) - DUK_ASC_0;

		if (dig <= 9U) {
			/* Careful overflow handling.  When multiplying by 10:
			 * - 0x19999998 x 10 = 0xfffffff0: no overflow, and adding
			 *   0...9 is safe.
			 * - 0x19999999 x 10 = 0xfffffffa: no overflow, adding
			 *   0...5 is safe, 6...9 overflows.
			 * - 0x1999999a x 10 = 0x100000004: always overflow.
			 */
			if (DUK_UNLIKELY(res >= 0x19999999UL)) {
				if (res >= 0x1999999aUL) {
					/* Always overflow. */
					goto parse_fail;
				}
				DUK_ASSERT(res == 0x19999999UL);
				if (dig >= 6U) {
					goto parse_fail;
				}
				res = 0xfffffffaUL + dig;
				DUK_ASSERT(res >= 0xfffffffaUL);
				DUK_ASSERT_DISABLE(res <= 0xffffffffUL);  /* range */
			} else {
				res = res * 10U + dig;
				if (DUK_UNLIKELY(res == 0)) {
					/* If 'res' is 0, previous 'res' must
					 * have been 0 and we scanned in a zero.
					 * This is only allowed if blen == 1,
					 * i.e. the exact string '0'.
					 */
					if (blen == (duk_uint32_t) 1) {
						return 0;
					}
					goto parse_fail;
				}
			}
		} else {
			/* Because 'dig' is unsigned, catches both values
			 * above '9' and below '0'.
			 */
			goto parse_fail;
		}
	} while (--blen > 0);

	return res;

 parse_fail:
	return DUK_HSTRING_NO_ARRAY_INDEX;
}

#if !defined(DUK_USE_HSTRING_ARRIDX)
/* Get array index for a string which is known to be an array index.  This helper
 * is needed when duk_hstring doesn't concretely store the array index, but strings
 * are flagged as array indices at intern time.
 */
DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_hstring_fast_known(duk_hstring *h) {
	const duk_uint8_t *p;
	duk_uarridx_t res;
	duk_uint8_t t;

	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HSTRING_HAS_ARRIDX(h));

	p = DUK_HSTRING_GET_DATA(h);
	res = 0;
	for (;;) {
		t = *p++;
		if (DUK_UNLIKELY(t == 0)) {
			/* Scanning to NUL is always safe for interned strings. */
			break;
		}
		DUK_ASSERT(t >= (duk_uint8_t) DUK_ASC_0 && t <= (duk_uint8_t) DUK_ASC_9);
		res = res * 10U + (duk_uarridx_t) t - (duk_uarridx_t) DUK_ASC_0;
	}
	return res;
}

DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_hstring_fast(duk_hstring *h) {
	DUK_ASSERT(h != NULL);
	if (!DUK_HSTRING_HAS_ARRIDX(h)) {
		return DUK_HSTRING_NO_ARRAY_INDEX;
	}
	return duk_js_to_arrayindex_hstring_fast_known(h);
}
#endif  /* DUK_USE_HSTRING_ARRIDX */
/*
 *  Identifier access and function closure handling.
 *
 *  Provides the primitives for slow path identifier accesses: GETVAR,
 *  PUTVAR, DELVAR, etc.  The fast path, direct register accesses, should
 *  be used for most identifier accesses.  Consequently, these slow path
 *  primitives should be optimized for maximum compactness.
 *
 *  ECMAScript environment records (declarative and object) are represented
 *  as internal objects with control keys.  Environment records have a
 *  parent record ("outer environment reference") which is represented by
 *  the implicit prototype for technical reasons (in other words, it is a
 *  convenient field).  The prototype chain is not followed in the ordinary
 *  sense for variable lookups.
 *
 *  See identifier-handling.rst for more details on the identifier algorithms
 *  and the internal representation.  See function-objects.rst for details on
 *  what function templates and instances are expected to look like.
 *
 *  Care must be taken to avoid duk_tval pointer invalidation caused by
 *  e.g. value stack or object resizing.
 *
 *  TODO: properties for function instances could be initialized much more
 *  efficiently by creating a property allocation for a certain size and
 *  filling in keys and values directly (and INCREFing both with "bulk incref"
 *  primitives.
 *
 *  XXX: duk_hobject_getprop() and duk_hobject_putprop() calls are a bit
 *  awkward (especially because they follow the prototype chain); rework
 *  if "raw" own property helpers are added.
 */

/* #include duk_internal.h -> already included */

/*
 *  Local result type for duk__get_identifier_reference() lookup.
 */

typedef struct {
	duk_hobject *env;
	duk_hobject *holder;      /* for object-bound identifiers */
	duk_tval *value;          /* for register-bound and declarative env identifiers */
	duk_uint_t attrs;         /* property attributes for identifier (relevant if value != NULL) */
	duk_bool_t has_this;      /* for object-bound identifiers: provide 'this' binding */
} duk__id_lookup_result;

/*
 *  Create a new function object based on a "template function" which contains
 *  compiled bytecode, constants, etc, but lacks a lexical environment.
 *
 *  ECMAScript requires that each created closure is a separate object, with
 *  its own set of editable properties.  However, structured property values
 *  (such as the formal arguments list and the variable map) are shared.
 *  Also the bytecode, constants, and inner functions are shared.
 *
 *  See E5 Section 13.2 for detailed requirements on the function objects;
 *  there are no similar requirements for function "templates" which are an
 *  implementation dependent internal feature.  Also see function-objects.rst
 *  for a discussion on the function instance properties provided by this
 *  implementation.
 *
 *  Notes:
 *
 *   * Order of internal properties should match frequency of use, since the
 *     properties will be linearly scanned on lookup (functions usually don't
 *     have enough properties to warrant a hash part).
 *
 *   * The created closure is independent of its template; they do share the
 *     same 'data' buffer object, but the template object itself can be freed
 *     even if the closure object remains reachable.
 */

DUK_LOCAL void duk__inc_data_inner_refcounts(duk_hthread *thr, duk_hcompfunc *f) {
	duk_tval *tv, *tv_end;
	duk_hobject **funcs, **funcs_end;

	DUK_UNREF(thr);

	/* If function creation fails due to out-of-memory, the data buffer
	 * pointer may be NULL in some cases.  That's actually possible for
	 * GC code, but shouldn't be possible here because the incomplete
	 * function will be unwound from the value stack and never instantiated.
	 */
	DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, f) != NULL);

	tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, f);
	tv_end = DUK_HCOMPFUNC_GET_CONSTS_END(thr->heap, f);
	while (tv < tv_end) {
		DUK_TVAL_INCREF(thr, tv);
		tv++;
	}

	funcs = DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, f);
	funcs_end = DUK_HCOMPFUNC_GET_FUNCS_END(thr->heap, f);
	while (funcs < funcs_end) {
		DUK_HEAPHDR_INCREF(thr, (duk_heaphdr *) *funcs);
		funcs++;
	}
}

/* Push a new closure on the stack.
 *
 * Note: if fun_temp has NEWENV, i.e. a new lexical and variable declaration
 * is created when the function is called, only outer_lex_env matters
 * (outer_var_env is ignored and may or may not be same as outer_lex_env).
 */

DUK_LOCAL const duk_uint16_t duk__closure_copy_proplist[] = {
	/* order: most frequent to least frequent */
	DUK_STRIDX_INT_VARMAP,
	DUK_STRIDX_INT_FORMALS,
#if defined(DUK_USE_PC2LINE)
	DUK_STRIDX_INT_PC2LINE,
#endif
#if defined(DUK_USE_FUNC_FILENAME_PROPERTY)
	DUK_STRIDX_FILE_NAME,
#endif
#if defined(DUK_USE_NONSTD_FUNC_SOURCE_PROPERTY)
	DUK_STRIDX_INT_SOURCE
#endif
};

DUK_INTERNAL
void duk_js_push_closure(duk_hthread *thr,
                         duk_hcompfunc *fun_temp,
                         duk_hobject *outer_var_env,
                         duk_hobject *outer_lex_env,
                         duk_bool_t add_auto_proto) {
	duk_hcompfunc *fun_clos;
	duk_harray *formals;
	duk_small_uint_t i;
	duk_uint_t len_value;

	DUK_ASSERT(fun_temp != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, fun_temp) != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_FUNCS(thr->heap, fun_temp) != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_BYTECODE(thr->heap, fun_temp) != NULL);
	DUK_ASSERT(outer_var_env != NULL);
	DUK_ASSERT(outer_lex_env != NULL);
	DUK_UNREF(len_value);

	DUK_STATS_INC(thr->heap, stats_envrec_pushclosure);

	fun_clos = duk_push_hcompfunc(thr);
	DUK_ASSERT(fun_clos != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) fun_clos) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);

	duk_push_hobject(thr, &fun_temp->obj);  /* -> [ ... closure template ] */

	DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC((duk_hobject *) fun_clos));
	DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, fun_clos) == NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_FUNCS(thr->heap, fun_clos) == NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_BYTECODE(thr->heap, fun_clos) == NULL);

	DUK_HCOMPFUNC_SET_DATA(thr->heap, fun_clos, DUK_HCOMPFUNC_GET_DATA(thr->heap, fun_temp));
	DUK_HCOMPFUNC_SET_FUNCS(thr->heap, fun_clos, DUK_HCOMPFUNC_GET_FUNCS(thr->heap, fun_temp));
	DUK_HCOMPFUNC_SET_BYTECODE(thr->heap, fun_clos, DUK_HCOMPFUNC_GET_BYTECODE(thr->heap, fun_temp));

	/* Note: all references inside 'data' need to get their refcounts
	 * upped too.  This is the case because refcounts are decreased
	 * through every function referencing 'data' independently.
	 */

	DUK_HBUFFER_INCREF(thr, DUK_HCOMPFUNC_GET_DATA(thr->heap, fun_clos));
	duk__inc_data_inner_refcounts(thr, fun_temp);

	fun_clos->nregs = fun_temp->nregs;
	fun_clos->nargs = fun_temp->nargs;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
	fun_clos->start_line = fun_temp->start_line;
	fun_clos->end_line = fun_temp->end_line;
#endif

	DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, fun_clos) != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_FUNCS(thr->heap, fun_clos) != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_BYTECODE(thr->heap, fun_clos) != NULL);

	/* XXX: Could also copy from template, but there's no way to have any
	 * other value here now (used code has no access to the template).
	 * Prototype is set by duk_push_hcompfunc().
	 */
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, &fun_clos->obj) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
#if 0
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, &fun_clos->obj, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
#endif

	/* Copy duk_hobject flags as is from the template using a mask.
	 * Leave out duk_heaphdr owned flags just in case (e.g. if there's
	 * some GC flag or similar).  Some flags can then be adjusted
	 * separately if necessary.
	 */

	/* DUK_HEAPHDR_SET_FLAGS() masks changes to non-duk_heaphdr flags only. */
	DUK_HEAPHDR_SET_FLAGS((duk_heaphdr *) fun_clos, DUK_HEAPHDR_GET_FLAGS_RAW((duk_heaphdr *) fun_temp));
	DUK_DD(DUK_DDPRINT("fun_temp heaphdr flags: 0x%08lx, fun_clos heaphdr flags: 0x%08lx",
	                   (unsigned long) DUK_HEAPHDR_GET_FLAGS_RAW((duk_heaphdr *) fun_temp),
	                   (unsigned long) DUK_HEAPHDR_GET_FLAGS_RAW((duk_heaphdr *) fun_clos)));

	DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(&fun_clos->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(&fun_clos->obj));
	DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(&fun_clos->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(&fun_clos->obj));
	DUK_ASSERT(!DUK_HOBJECT_IS_THREAD(&fun_clos->obj));
	/* DUK_HOBJECT_FLAG_ARRAY_PART: don't care */
	/* DUK_HOBJECT_FLAG_NEWENV: handled below */
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(&fun_clos->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(&fun_clos->obj));
	DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(&fun_clos->obj));

	if (!DUK_HOBJECT_HAS_CONSTRUCTABLE(&fun_clos->obj)) {
		/* If the template is not constructable don't add an automatic
		 * .prototype property.  This is the case for e.g. ES2015 object
		 * literal getters/setters and method definitions.
		 */
		add_auto_proto = 0;
	}

	/*
	 *  Setup environment record properties based on the template and
	 *  its flags.
	 *
	 *  If DUK_HOBJECT_HAS_NEWENV(fun_temp) is true, the environment
	 *  records represent identifiers "outside" the function; the
	 *  "inner" environment records are created on demand.  Otherwise,
	 *  the environment records are those that will be directly used
	 *  (e.g. for declarations).
	 *
	 *  _Lexenv is always set; _Varenv defaults to _Lexenv if missing,
	 *  so _Varenv is only set if _Lexenv != _Varenv.
	 *
	 *  This is relatively complex, see doc/identifier-handling.rst.
	 */

	if (DUK_HOBJECT_HAS_NEWENV(&fun_clos->obj)) {
#if defined(DUK_USE_FUNC_NAME_PROPERTY)
		if (DUK_HOBJECT_HAS_NAMEBINDING(&fun_clos->obj)) {
			duk_hobject *proto;
			duk_hdecenv *new_env;

			/*
			 *  Named function expression, name needs to be bound
			 *  in an intermediate environment record.  The "outer"
			 *  lexical/variable environment will thus be:
			 *
			 *  a) { funcname: <func>, __prototype: outer_lex_env }
			 *  b) { funcname: <func>, __prototype:  <globalenv> }  (if outer_lex_env missing)
			 */

			if (outer_lex_env) {
				proto = outer_lex_env;
			} else {
				proto = thr->builtins[DUK_BIDX_GLOBAL_ENV];
			}

			/* -> [ ... closure template env ] */
			new_env = duk_hdecenv_alloc(thr,
			                            DUK_HOBJECT_FLAG_EXTENSIBLE |
			                            DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV));
			DUK_ASSERT(new_env != NULL);
			duk_push_hobject(thr, (duk_hobject *) new_env);

			DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) new_env) == NULL);
			DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) new_env, proto);
			DUK_HOBJECT_INCREF_ALLOWNULL(thr, proto);

			DUK_ASSERT(new_env->thread == NULL);  /* Closed. */
			DUK_ASSERT(new_env->varmap == NULL);

			/* It's important that duk_xdef_prop() is a 'raw define' so that any
			 * properties in an ancestor are never an issue (they should never be
			 * e.g. non-writable, but just in case).
			 *
			 * Because template objects are not visible to user code, the case
			 * where .name is missing shouldn't happen in practice.  It it does,
			 * the name 'undefined' gets bound and maps to the closure (which is
			 * a bit odd, but safe).
			 */
			(void) duk_get_prop_stridx_short(thr, -2, DUK_STRIDX_NAME);
			/* -> [ ... closure template env funcname ] */
			duk_dup_m4(thr);                                           /* -> [ ... closure template env funcname closure ] */
			duk_xdef_prop(thr, -3, DUK_PROPDESC_FLAGS_NONE);           /* -> [ ... closure template env ] */
			/* env[funcname] = closure */

			/* [ ... closure template env ] */

			DUK_HCOMPFUNC_SET_LEXENV(thr->heap, fun_clos, (duk_hobject *) new_env);
			DUK_HCOMPFUNC_SET_VARENV(thr->heap, fun_clos, (duk_hobject *) new_env);
			DUK_HOBJECT_INCREF(thr, (duk_hobject *) new_env);
			DUK_HOBJECT_INCREF(thr, (duk_hobject *) new_env);
			duk_pop_unsafe(thr);

			/* [ ... closure template ] */
		}
		else
#endif  /* DUK_USE_FUNC_NAME_PROPERTY */
		{
			/*
			 *  Other cases (function declaration, anonymous function expression,
			 *  strict direct eval code).  The "outer" environment will be whatever
			 *  the caller gave us.
			 */

			DUK_HCOMPFUNC_SET_LEXENV(thr->heap, fun_clos, outer_lex_env);
			DUK_HCOMPFUNC_SET_VARENV(thr->heap, fun_clos, outer_lex_env);
			DUK_HOBJECT_INCREF(thr, outer_lex_env);
			DUK_HOBJECT_INCREF(thr, outer_lex_env);

			/* [ ... closure template ] */
		}
	} else {
		/*
		 *  Function gets no new environment when called.  This is the
		 *  case for global code, indirect eval code, and non-strict
		 *  direct eval code.  There is no direct correspondence to the
		 *  E5 specification, as global/eval code is not exposed as a
		 *  function.
		 */

		DUK_ASSERT(!DUK_HOBJECT_HAS_NAMEBINDING(&fun_temp->obj));

		DUK_HCOMPFUNC_SET_LEXENV(thr->heap, fun_clos, outer_lex_env);
		DUK_HCOMPFUNC_SET_VARENV(thr->heap, fun_clos, outer_var_env);
		DUK_HOBJECT_INCREF(thr, outer_lex_env);  /* NULLs not allowed; asserted on entry */
		DUK_HOBJECT_INCREF(thr, outer_var_env);
	}
	DUK_DDD(DUK_DDDPRINT("closure varenv -> %!ipO, lexenv -> %!ipO",
	                     (duk_heaphdr *) fun_clos->var_env,
	                     (duk_heaphdr *) fun_clos->lex_env));

	/* Call handling assumes this for all callable closures. */
	DUK_ASSERT(DUK_HCOMPFUNC_GET_LEXENV(thr->heap, fun_clos) != NULL);
	DUK_ASSERT(DUK_HCOMPFUNC_GET_VARENV(thr->heap, fun_clos) != NULL);

	/*
	 *  Copy some internal properties directly
	 *
	 *  The properties will be non-writable and non-enumerable, but
	 *  configurable.
	 *
	 *  Function templates are bare objects, so inheritance of internal
	 *  Symbols is not an issue here even when using ordinary property
	 *  reads.  The function instance created is not bare, so internal
	 *  Symbols must be defined without inheritance checks.
	 */

	/* [ ... closure template ] */

	DUK_DDD(DUK_DDDPRINT("copying properties: closure=%!iT, template=%!iT",
	                     (duk_tval *) duk_get_tval(thr, -2),
	                     (duk_tval *) duk_get_tval(thr, -1)));

	for (i = 0; i < (duk_small_uint_t) (sizeof(duk__closure_copy_proplist) / sizeof(duk_uint16_t)); i++) {
		duk_small_int_t stridx = (duk_small_int_t) duk__closure_copy_proplist[i];
		if (duk_xget_owndataprop_stridx_short(thr, -1, stridx)) {
			/* [ ... closure template val ] */
			DUK_DDD(DUK_DDDPRINT("copying property, stridx=%ld -> found", (long) stridx));
			duk_xdef_prop_stridx_short(thr, -3, stridx, DUK_PROPDESC_FLAGS_C);
		} else {
			DUK_DDD(DUK_DDDPRINT("copying property, stridx=%ld -> not found", (long) stridx));
			duk_pop_unsafe(thr);
		}
	}

	/*
	 *  "length" maps to number of formals (E5 Section 13.2) for function
	 *  declarations/expressions (non-bound functions).  Note that 'nargs'
	 *  is NOT necessarily equal to the number of arguments.  Use length
	 *  of _Formals; if missing, assume nargs matches .length.
	 */

	/* [ ... closure template ] */

	formals = duk_hobject_get_formals(thr, (duk_hobject *) fun_temp);
	if (formals) {
		len_value = (duk_uint_t) formals->length;
		DUK_DD(DUK_DDPRINT("closure length from _Formals -> %ld", (long) len_value));
	} else {
		len_value = fun_temp->nargs;
		DUK_DD(DUK_DDPRINT("closure length defaulted from nargs -> %ld", (long) len_value));
	}

	duk_push_uint(thr, len_value);  /* [ ... closure template len_value ] */
	duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_C);

	/*
	 *  "prototype" is, by default, a fresh object with the "constructor"
	 *  property.
	 *
	 *  Note that this creates a circular reference for every function
	 *  instance (closure) which prevents refcount-based collection of
	 *  function instances.
	 *
	 *  XXX: Try to avoid creating the default prototype object, because
	 *  many functions are not used as constructors and the default
	 *  prototype is unnecessary.  Perhaps it could be created on-demand
	 *  when it is first accessed?
	 */

	/* [ ... closure template ] */

	if (add_auto_proto) {
		duk_push_object(thr);  /* -> [ ... closure template newobj ] */
		duk_dup_m3(thr);       /* -> [ ... closure template newobj closure ] */
		duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_CONSTRUCTOR, DUK_PROPDESC_FLAGS_WC);  /* -> [ ... closure template newobj ] */
		duk_compact(thr, -1);  /* compact the prototype */
		duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_PROTOTYPE, DUK_PROPDESC_FLAGS_W);     /* -> [ ... closure template ] */
	}

	/*
	 *  "arguments" and "caller" must be mapped to throwers for strict
	 *  mode and bound functions (E5 Section 15.3.5).
	 *
	 *  XXX: This is expensive to have for every strict function instance.
	 *  Try to implement as virtual properties or on-demand created properties.
	 */

	/* [ ... closure template ] */

	if (DUK_HOBJECT_HAS_STRICT(&fun_clos->obj)) {
		duk_xdef_prop_stridx_thrower(thr, -2, DUK_STRIDX_CALLER);
		duk_xdef_prop_stridx_thrower(thr, -2, DUK_STRIDX_LC_ARGUMENTS);
	} else {
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
		DUK_DDD(DUK_DDDPRINT("function is non-strict and non-standard 'caller' property in use, add initial 'null' value"));
		duk_push_null(thr);
		duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_CALLER, DUK_PROPDESC_FLAGS_NONE);
#else
		DUK_DDD(DUK_DDDPRINT("function is non-strict and non-standard 'caller' property not used"));
#endif
	}

	/*
	 *  "name" used to be non-standard but is now defined by ES2015.
	 *  In ES2015/ES2016 the .name property is configurable.
	 */

	/* [ ... closure template ] */

#if defined(DUK_USE_FUNC_NAME_PROPERTY)
	/* XXX: Look for own property only; doesn't matter much because
	 * templates are bare objects.
	 */
	if (duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_NAME)) {
		/* [ ... closure template name ] */
		DUK_ASSERT(duk_is_string(thr, -1));
		DUK_DD(DUK_DDPRINT("setting function instance name to %!T", duk_get_tval(thr, -1)));
		duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_C);  /* -> [ ... closure template ] */
	} else {
		/* Anonymous functions don't have a .name in ES2015, so don't set
		 * it on the instance either.  The instance will then inherit
		 * it from Function.prototype.name.
		 */
		DUK_DD(DUK_DDPRINT("not setting function instance .name"));
		duk_pop_unsafe(thr);
	}
#endif

	/*
	 *  Compact the closure, in most cases no properties will be added later.
	 *  Also, without this the closures end up having unused property slots
	 *  (e.g. in Duktape 0.9.0, 8 slots would be allocated and only 7 used).
	 *  A better future solution would be to allocate the closure directly
	 *  to correct size (and setup the properties directly without going
	 *  through the API).
	 */

	duk_compact(thr, -2);

	/*
	 *  Some assertions (E5 Section 13.2).
	 */

	DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(&fun_clos->obj) == DUK_HOBJECT_CLASS_FUNCTION);
	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, &fun_clos->obj) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
	DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(&fun_clos->obj));
	DUK_ASSERT(duk_has_prop_stridx(thr, -2, DUK_STRIDX_LENGTH) != 0);
	DUK_ASSERT(add_auto_proto == 0 || duk_has_prop_stridx(thr, -2, DUK_STRIDX_PROTOTYPE) != 0);
	/* May be missing .name */
	DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(&fun_clos->obj) ||
	           duk_has_prop_stridx(thr, -2, DUK_STRIDX_CALLER) != 0);
	DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(&fun_clos->obj) ||
	           duk_has_prop_stridx(thr, -2, DUK_STRIDX_LC_ARGUMENTS) != 0);

	/*
	 *  Finish
	 */

	/* [ ... closure template ] */

	DUK_DDD(DUK_DDDPRINT("created function instance: template=%!iT -> closure=%!iT",
	                     (duk_tval *) duk_get_tval(thr, -1),
	                     (duk_tval *) duk_get_tval(thr, -2)));

	duk_pop_unsafe(thr);

	/* [ ... closure ] */
}

/*
 *  Delayed activation environment record initialization (for functions
 *  with NEWENV).
 *
 *  The non-delayed initialization is handled by duk_handle_call().
 */

DUK_LOCAL void duk__preallocate_env_entries(duk_hthread *thr, duk_hobject *varmap, duk_hobject *env) {
	duk_uint_fast32_t i;

	for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(varmap); i++) {
		duk_hstring *key;

		key = DUK_HOBJECT_E_GET_KEY(thr->heap, varmap, i);
		DUK_ASSERT(key != NULL);   /* assume keys are compact in _Varmap */
		DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, varmap, i));  /* assume plain values */

		/* Predefine as 'undefined' to reserve a property slot.
		 * This makes the unwind process (where register values
		 * are copied to the env object) safe against throwing.
		 *
		 * XXX: This could be made much faster by creating the
		 * property table directly.
		 */
		duk_push_undefined(thr);
		DUK_DDD(DUK_DDDPRINT("preallocate env entry for key %!O", key));
		duk_hobject_define_property_internal(thr, env, key, DUK_PROPDESC_FLAGS_WE);
	}
}

/* shared helper */
DUK_INTERNAL
duk_hobject *duk_create_activation_environment_record(duk_hthread *thr,
                                                      duk_hobject *func,
                                                      duk_size_t bottom_byteoff) {
	duk_hdecenv *env;
	duk_hobject *parent;
	duk_hcompfunc *f;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(func != NULL);

	DUK_STATS_INC(thr->heap, stats_envrec_create);

	f = (duk_hcompfunc *) func;
	parent = DUK_HCOMPFUNC_GET_LEXENV(thr->heap, f);
	if (!parent) {
		parent = thr->builtins[DUK_BIDX_GLOBAL_ENV];
	}

	env = duk_hdecenv_alloc(thr,
	                        DUK_HOBJECT_FLAG_EXTENSIBLE |
	                        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV));
	DUK_ASSERT(env != NULL);
	duk_push_hobject(thr, (duk_hobject *) env);

	DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, (duk_hobject *) env) == NULL);
	DUK_HOBJECT_SET_PROTOTYPE(thr->heap, (duk_hobject *) env, parent);
	DUK_HOBJECT_INCREF_ALLOWNULL(thr, parent);  /* parent env is the prototype */

	/* open scope information, for compiled functions only */

	DUK_ASSERT(env->thread == NULL);
	DUK_ASSERT(env->varmap == NULL);
	DUK_ASSERT(env->regbase_byteoff == 0);
	if (DUK_HOBJECT_IS_COMPFUNC(func)) {
		duk_hobject *varmap;

		varmap = duk_hobject_get_varmap(thr, func);
		if (varmap != NULL) {
			env->varmap = varmap;
			DUK_HOBJECT_INCREF(thr, varmap);
			env->thread = thr;
			DUK_HTHREAD_INCREF(thr, thr);
			env->regbase_byteoff = bottom_byteoff;

			/* Preallocate env property table to avoid potential
			 * for out-of-memory on unwind when the env is closed.
			 */
			duk__preallocate_env_entries(thr, varmap, (duk_hobject *) env);
		} else {
			/* If function has no _Varmap, leave the environment closed. */
			DUK_ASSERT(env->thread == NULL);
			DUK_ASSERT(env->varmap == NULL);
			DUK_ASSERT(env->regbase_byteoff == 0);
		}
	}

	return (duk_hobject *) env;
}

DUK_INTERNAL
void duk_js_init_activation_environment_records_delayed(duk_hthread *thr,
                                                        duk_activation *act) {
	duk_hobject *func;
	duk_hobject *env;

	DUK_ASSERT(thr != NULL);
	func = DUK_ACT_GET_FUNC(act);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));  /* bound functions are never in act 'func' */

	/*
	 *  Delayed initialization only occurs for 'NEWENV' functions.
	 */

	DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func));
	DUK_ASSERT(act->lex_env == NULL);
	DUK_ASSERT(act->var_env == NULL);

	DUK_STATS_INC(thr->heap, stats_envrec_delayedcreate);

	env = duk_create_activation_environment_record(thr, func, act->bottom_byteoff);
	DUK_ASSERT(env != NULL);
	/* 'act' is a stable pointer, so still OK. */

	DUK_DDD(DUK_DDDPRINT("created delayed fresh env: %!ipO", (duk_heaphdr *) env));
#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
	{
		duk_hobject *p = env;
		while (p) {
			DUK_DDD(DUK_DDDPRINT("  -> %!ipO", (duk_heaphdr *) p));
			p = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, p);
		}
	}
#endif

	act->lex_env = env;
	act->var_env = env;
	DUK_HOBJECT_INCREF(thr, env);  /* XXX: incref by count (here 2 times) */
	DUK_HOBJECT_INCREF(thr, env);

	duk_pop_unsafe(thr);
}

/*
 *  Closing environment records.
 *
 *  The environment record MUST be closed with the thread where its activation
 *  is; i.e. if 'env' is open, 'thr' must match env->thread, and the regbase
 *  and varmap must still be valid.  On entry, 'env' must be reachable.
 */

DUK_INTERNAL void duk_js_close_environment_record(duk_hthread *thr, duk_hobject *env) {
	duk_uint_fast32_t i;
	duk_hobject *varmap;
	duk_hstring *key;
	duk_tval *tv;
	duk_uint_t regnum;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(env != NULL);

	if (DUK_UNLIKELY(!DUK_HOBJECT_IS_DECENV(env))) {
		DUK_DDD(DUK_DDDPRINT("env not a declarative record: %!iO", (duk_heaphdr *) env));
		return;
	}

	varmap = ((duk_hdecenv *) env)->varmap;
	if (varmap == NULL) {
		DUK_DDD(DUK_DDDPRINT("env already closed: %!iO", (duk_heaphdr *) env));

		return;
	}
	DUK_ASSERT(((duk_hdecenv *) env)->thread != NULL);
	DUK_HDECENV_ASSERT_VALID((duk_hdecenv *) env);

	DUK_DDD(DUK_DDDPRINT("closing env: %!iO", (duk_heaphdr *) env));
	DUK_DDD(DUK_DDDPRINT("varmap: %!O", (duk_heaphdr *) varmap));

	/* Env must be closed in the same thread as where it runs. */
	DUK_ASSERT(((duk_hdecenv *) env)->thread == thr);

	/* XXX: additional conditions when to close variables? we don't want to do it
	 * unless the environment may have "escaped" (referenced in a function closure).
	 * With delayed environments, the existence is probably good enough of a check.
	 */

	/* Note: we rely on the _Varmap having a bunch of nice properties, like:
	 *  - being compacted and unmodified during this process
	 *  - not containing an array part
	 *  - having correct value types
	 */

	DUK_DDD(DUK_DDDPRINT("copying bound register values, %ld bound regs", (long) DUK_HOBJECT_GET_ENEXT(varmap)));

	/* Copy over current variable values from value stack to the
	 * environment record.  The scope object is empty but may
	 * inherit from another scope which has conflicting names.
	 */

	/* XXX: Do this using a once allocated entry area, no side effects.
	 * Hash part would need special treatment however (maybe copy, and
	 * then realloc with hash part if large enough).
	 */
	for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(varmap); i++) {
		duk_size_t regbase_byteoff;

		key = DUK_HOBJECT_E_GET_KEY(thr->heap, varmap, i);
		DUK_ASSERT(key != NULL);   /* assume keys are compact in _Varmap */
		DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, varmap, i));  /* assume plain values */

		tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, varmap, i);
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		DUK_ASSERT(DUK_TVAL_GET_NUMBER(tv) <= (duk_double_t) DUK_UINT32_MAX);  /* limits */
#if defined(DUK_USE_FASTINT)
		DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv));
		regnum = (duk_uint_t) DUK_TVAL_GET_FASTINT_U32(tv);
#else
		regnum = (duk_uint_t) DUK_TVAL_GET_NUMBER(tv);
#endif

		regbase_byteoff = ((duk_hdecenv *) env)->regbase_byteoff;
		DUK_ASSERT((duk_uint8_t *) thr->valstack + regbase_byteoff + sizeof(duk_tval) * regnum >= (duk_uint8_t *) thr->valstack);
		DUK_ASSERT((duk_uint8_t *) thr->valstack + regbase_byteoff + sizeof(duk_tval) * regnum < (duk_uint8_t *) thr->valstack_top);

		/* Write register value into env as named properties.
		 * If property already exists, overwrites silently.
		 * Property is writable, but not deletable (not configurable
		 * in terms of property attributes).
		 *
		 * This property write must not throw because we're unwinding
		 * and unwind code is not allowed to throw at present.  The
		 * call itself has no such guarantees, but we've preallocated
		 * entries for each property when the env was created, so no
		 * out-of-memory error should be possible.  If this guarantee
		 * is not provided, problems like GH-476 may happen.
		 */
		duk_push_tval(thr, (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + regbase_byteoff + sizeof(duk_tval) * regnum));
		DUK_DDD(DUK_DDDPRINT("closing identifier %!O -> reg %ld, value %!T",
		                     (duk_heaphdr *) key,
		                     (long) regnum,
		                     (duk_tval *) duk_get_tval(thr, -1)));
		duk_hobject_define_property_internal(thr, env, key, DUK_PROPDESC_FLAGS_WE);
	}

	/* NULL atomically to avoid inconsistent state + side effects. */
	DUK_HOBJECT_DECREF_NORZ(thr, ((duk_hdecenv *) env)->thread);
	DUK_HOBJECT_DECREF_NORZ(thr, ((duk_hdecenv *) env)->varmap);
	((duk_hdecenv *) env)->thread = NULL;
	((duk_hdecenv *) env)->varmap = NULL;

	DUK_DDD(DUK_DDDPRINT("env after closing: %!O", (duk_heaphdr *) env));
}

/*
 *  GETIDREF: a GetIdentifierReference-like helper.
 *
 *  Provides a parent traversing lookup and a single level lookup
 *  (for HasBinding).
 *
 *  Instead of returning the value, returns a bunch of values allowing
 *  the caller to read, write, or delete the binding.  Value pointers
 *  are duk_tval pointers which can be mutated directly as long as
 *  refcounts are properly updated.  Note that any operation which may
 *  reallocate valstacks or compact objects may invalidate the returned
 *  duk_tval (but not object) pointers, so caller must be very careful.
 *
 *  If starting environment record 'env' is given, 'act' is ignored.
 *  However, if 'env' is NULL, the caller may identify, in 'act', an
 *  activation which hasn't had its declarative environment initialized
 *  yet.  The activation registers are then looked up, and its parent
 *  traversed normally.
 *
 *  The 'out' structure values are only valid if the function returns
 *  success (non-zero).
 */

/* lookup name from an open declarative record's registers */
DUK_LOCAL
duk_bool_t duk__getid_open_decl_env_regs(duk_hthread *thr,
                                         duk_hstring *name,
                                         duk_hdecenv *env,
                                         duk__id_lookup_result *out) {
	duk_tval *tv;
	duk_size_t reg_rel;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(name != NULL);
	DUK_ASSERT(env != NULL);
	DUK_ASSERT(out != NULL);

	DUK_ASSERT(DUK_HOBJECT_IS_DECENV((duk_hobject *) env));
	DUK_HDECENV_ASSERT_VALID(env);

	if (env->thread == NULL) {
		/* already closed */
		return 0;
	}
	DUK_ASSERT(env->varmap != NULL);

	tv = duk_hobject_find_entry_tval_ptr(thr->heap, env->varmap, name);
	if (DUK_UNLIKELY(tv == NULL)) {
		return 0;
	}

	DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
	DUK_ASSERT(DUK_TVAL_GET_NUMBER(tv) <= (duk_double_t) DUK_UINT32_MAX);  /* limits */
#if defined(DUK_USE_FASTINT)
	DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv));
	reg_rel = (duk_size_t) DUK_TVAL_GET_FASTINT_U32(tv);
#else
	reg_rel = (duk_size_t) DUK_TVAL_GET_NUMBER(tv);
#endif
	DUK_ASSERT_DISABLE(reg_rel >= 0);  /* unsigned */

	tv = (duk_tval *) (void *) ((duk_uint8_t *) env->thread->valstack + env->regbase_byteoff + sizeof(duk_tval) * reg_rel);
	DUK_ASSERT(tv >= env->thread->valstack && tv < env->thread->valstack_end);  /* XXX: more accurate? */

	out->value = tv;
	out->attrs = DUK_PROPDESC_FLAGS_W;  /* registers are mutable, non-deletable */
	out->env = (duk_hobject *) env;
	out->holder = NULL;
	out->has_this = 0;
	return 1;
}

/* lookup name from current activation record's functions' registers */
DUK_LOCAL
duk_bool_t duk__getid_activation_regs(duk_hthread *thr,
                                      duk_hstring *name,
                                      duk_activation *act,
                                      duk__id_lookup_result *out) {
	duk_tval *tv;
	duk_hobject *func;
	duk_hobject *varmap;
	duk_size_t reg_rel;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(name != NULL);
	DUK_ASSERT(act != NULL);
	DUK_ASSERT(out != NULL);

	func = DUK_ACT_GET_FUNC(act);
	DUK_ASSERT(func != NULL);
	DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func));

	if (!DUK_HOBJECT_IS_COMPFUNC(func)) {
		return 0;
	}

	/* XXX: move varmap to duk_hcompfunc struct field? */
	varmap = duk_hobject_get_varmap(thr, func);
	if (!varmap) {
		return 0;
	}

	tv = duk_hobject_find_entry_tval_ptr(thr->heap, varmap, name);
	if (!tv) {
		return 0;
	}
	DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
	reg_rel = (duk_size_t) DUK_TVAL_GET_NUMBER(tv);
	DUK_ASSERT_DISABLE(reg_rel >= 0);
	DUK_ASSERT(reg_rel < ((duk_hcompfunc *) func)->nregs);

	tv = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + act->bottom_byteoff);
	tv += reg_rel;

	out->value = tv;
	out->attrs = DUK_PROPDESC_FLAGS_W;  /* registers are mutable, non-deletable */
	out->env = NULL;
	out->holder = NULL;
	out->has_this = 0;
	return 1;
}

DUK_LOCAL
duk_bool_t duk__get_identifier_reference(duk_hthread *thr,
                                         duk_hobject *env,
                                         duk_hstring *name,
                                         duk_activation *act,
                                         duk_bool_t parents,
                                         duk__id_lookup_result *out) {
	duk_tval *tv;
	duk_uint_t sanity;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(env != NULL || act != NULL);
	DUK_ASSERT(name != NULL);
	DUK_ASSERT(out != NULL);

	DUK_ASSERT(!env || DUK_HOBJECT_IS_ENV(env));
	DUK_ASSERT(!env || !DUK_HOBJECT_HAS_ARRAY_PART(env));

	/*
	 *  Conceptually, we look for the identifier binding by starting from
	 *  'env' and following to chain of environment records (represented
	 *  by the prototype chain).
	 *
	 *  If 'env' is NULL, the current activation does not yet have an
	 *  allocated declarative environment record; this should be treated
	 *  exactly as if the environment record existed but had no bindings
	 *  other than register bindings.
	 *
	 *  Note: we assume that with the DUK_HOBJECT_FLAG_NEWENV cleared
	 *  the environment will always be initialized immediately; hence
	 *  a NULL 'env' should only happen with the flag set.  This is the
	 *  case for: (1) function calls, and (2) strict, direct eval calls.
	 */

	if (env == NULL && act != NULL) {
		duk_hobject *func;
		duk_hcompfunc *f;

		DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference: env is NULL, activation is non-NULL -> "
		                     "delayed env case, look up activation regs first"));

		/*
		 *  Try registers
		 */

		if (duk__getid_activation_regs(thr, name, act, out)) {
			DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: "
			                     "name=%!O -> value=%!T, attrs=%ld, has_this=%ld, env=%!O, holder=%!O "
			                     "(found from register bindings when env=NULL)",
			                     (duk_heaphdr *) name, (duk_tval *) out->value,
			                     (long) out->attrs, (long) out->has_this,
			                     (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder));
			return 1;
		}

		DUK_DDD(DUK_DDDPRINT("not found in current activation regs"));

		/*
		 *  Not found in registers, proceed to the parent record.
		 *  Here we need to determine what the parent would be,
		 *  if 'env' was not NULL (i.e. same logic as when initializing
		 *  the record).
		 *
		 *  Note that environment initialization is only deferred when
		 *  DUK_HOBJECT_HAS_NEWENV is set, and this only happens for:
		 *    - Function code
		 *    - Strict eval code
		 *
		 *  We only need to check _Lexenv here; _Varenv exists only if it
		 *  differs from _Lexenv (and thus _Lexenv will also be present).
		 */

		if (!parents) {
			DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference failed, no parent traversal "
			                     "(not found from register bindings when env=NULL)"));
			goto fail_not_found;
		}

		func = DUK_ACT_GET_FUNC(act);
		DUK_ASSERT(func != NULL);
		DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func));
		f = (duk_hcompfunc *) func;

		env = DUK_HCOMPFUNC_GET_LEXENV(thr->heap, f);
		if (!env) {
			env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
		}

		DUK_DDD(DUK_DDDPRINT("continue lookup from env: %!iO",
		                     (duk_heaphdr *) env));
	}

	/*
	 *  Prototype walking starting from 'env'.
	 *
	 *  ('act' is not needed anywhere here.)
	 */

	sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
	while (env != NULL) {
		duk_small_uint_t cl;
		duk_uint_t attrs;

		DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference, name=%!O, considering env=%p -> %!iO",
		                     (duk_heaphdr *) name,
		                     (void *) env,
		                     (duk_heaphdr *) env));

		DUK_ASSERT(env != NULL);
		DUK_ASSERT(DUK_HOBJECT_IS_ENV(env));
		DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(env));

		cl = DUK_HOBJECT_GET_CLASS_NUMBER(env);
		DUK_ASSERT(cl == DUK_HOBJECT_CLASS_OBJENV || cl == DUK_HOBJECT_CLASS_DECENV);
		if (cl == DUK_HOBJECT_CLASS_DECENV) {
			/*
			 *  Declarative environment record.
			 *
			 *  Identifiers can never be stored in ancestors and are
			 *  always plain values, so we can use an internal helper
			 *  and access the value directly with an duk_tval ptr.
			 *
			 *  A closed environment is only indicated by it missing
			 *  the "book-keeping" properties required for accessing
			 *  register-bound variables.
			 */

			DUK_HDECENV_ASSERT_VALID((duk_hdecenv *) env);
			if (duk__getid_open_decl_env_regs(thr, name, (duk_hdecenv *) env, out)) {
				DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: "
				                     "name=%!O -> value=%!T, attrs=%ld, has_this=%ld, env=%!O, holder=%!O "
				                     "(declarative environment record, scope open, found in regs)",
				                     (duk_heaphdr *) name, (duk_tval *) out->value,
				                     (long) out->attrs, (long) out->has_this,
				                     (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder));
				return 1;
			}

			tv = duk_hobject_find_entry_tval_ptr_and_attrs(thr->heap, env, name, &attrs);
			if (tv) {
				out->value = tv;
				out->attrs = attrs;
				out->env = env;
				out->holder = env;
				out->has_this = 0;

				DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: "
				                     "name=%!O -> value=%!T, attrs=%ld, has_this=%ld, env=%!O, holder=%!O "
				                     "(declarative environment record, found in properties)",
				                     (duk_heaphdr *) name, (duk_tval *) out->value,
				                     (long) out->attrs, (long) out->has_this,
				                     (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder));
				return 1;
			}
		} else {
			/*
			 *  Object environment record.
			 *
			 *  Binding (target) object is an external, uncontrolled object.
			 *  Identifier may be bound in an ancestor property, and may be
			 *  an accessor.  Target can also be a Proxy which we must support
			 *  here.
			 */

			/* XXX: we could save space by using _Target OR _This.  If _Target, assume
			 * this binding is undefined.  If _This, assumes this binding is _This, and
			 * target is also _This.  One property would then be enough.
			 */

			duk_hobject *target;
			duk_bool_t found;

			DUK_ASSERT(cl == DUK_HOBJECT_CLASS_OBJENV);
			DUK_HOBJENV_ASSERT_VALID((duk_hobjenv *) env);

			target = ((duk_hobjenv *) env)->target;
			DUK_ASSERT(target != NULL);

			/* Target may be a Proxy or property may be an accessor, so we must
			 * use an actual, Proxy-aware hasprop check here.
			 *
			 * out->holder is NOT set to the actual duk_hobject where the
			 * property is found, but rather the object binding target object.
			 */

#if defined(DUK_USE_ES6_PROXY)
			if (DUK_UNLIKELY(DUK_HOBJECT_IS_PROXY(target))) {
				duk_tval tv_name;
				duk_tval tv_target_tmp;

				DUK_ASSERT(name != NULL);
				DUK_TVAL_SET_STRING(&tv_name, name);
				DUK_TVAL_SET_OBJECT(&tv_target_tmp, target);

				found = duk_hobject_hasprop(thr, &tv_target_tmp, &tv_name);
			} else
#endif  /* DUK_USE_ES6_PROXY */
			{
				/* XXX: duk_hobject_hasprop() would be correct for
				 * non-Proxy objects too, but it is about ~20-25%
				 * slower at present so separate code paths for
				 * Proxy and non-Proxy now.
				 */
				found = duk_hobject_hasprop_raw(thr, target, name);
			}

			if (found) {
				out->value = NULL;  /* can't get value, may be accessor */
				out->attrs = 0;     /* irrelevant when out->value == NULL */
				out->env = env;
				out->holder = target;
				out->has_this = ((duk_hobjenv *) env)->has_this;

				DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: "
				                     "name=%!O -> value=%!T, attrs=%ld, has_this=%ld, env=%!O, holder=%!O "
				                     "(object environment record)",
				                     (duk_heaphdr *) name, (duk_tval *) out->value,
				                     (long) out->attrs, (long) out->has_this,
				                     (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder));
				return 1;
			}
		}

		if (!parents) {
			DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference failed, no parent traversal "
			                     "(not found from first traversed env)"));
			goto fail_not_found;
		}

                if (DUK_UNLIKELY(sanity-- == 0)) {
                        DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
			DUK_WO_NORETURN(return 0;);
                }
		env = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, env);
	}

	/*
	 *  Not found (even in global object)
	 */

 fail_not_found:
	return 0;
}

/*
 *  HASVAR: check identifier binding from a given environment record
 *  without traversing its parents.
 *
 *  This primitive is not exposed to user code as such, but is used
 *  internally for e.g. declaration binding instantiation.
 *
 *  See E5 Sections:
 *    10.2.1.1.1 HasBinding(N)
 *    10.2.1.2.1 HasBinding(N)
 *
 *  Note: strictness has no bearing on this check.  Hence we don't take
 *  a 'strict' parameter.
 */

#if 0  /*unused*/
DUK_INTERNAL
duk_bool_t duk_js_hasvar_envrec(duk_hthread *thr,
                                duk_hobject *env,
                                duk_hstring *name) {
	duk__id_lookup_result ref;
	duk_bool_t parents;

	DUK_DDD(DUK_DDDPRINT("hasvar: thr=%p, env=%p, name=%!O "
	                     "(env -> %!dO)",
	                     (void *) thr, (void *) env, (duk_heaphdr *) name,
	                     (duk_heaphdr *) env));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(env != NULL);
	DUK_ASSERT(name != NULL);

        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env);
        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name);

	DUK_ASSERT(DUK_HOBJECT_IS_ENV(env));
	DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(env));

	/* lookup results is ignored */
	parents = 0;
	return duk__get_identifier_reference(thr, env, name, NULL, parents, &ref);
}
#endif

/*
 *  GETVAR
 *
 *  See E5 Sections:
 *    11.1.2 Identifier Reference
 *    10.3.1 Identifier Resolution
 *    11.13.1 Simple Assignment  [example of where the Reference is GetValue'd]
 *    8.7.1 GetValue (V)
 *    8.12.1 [[GetOwnProperty]] (P)
 *    8.12.2 [[GetProperty]] (P)
 *    8.12.3 [[Get]] (P)
 *
 *  If 'throw' is true, always leaves two values on top of stack: [val this].
 *
 *  If 'throw' is false, returns 0 if identifier cannot be resolved, and the
 *  stack will be unaffected in this case.  If identifier is resolved, returns
 *  1 and leaves [val this] on top of stack.
 *
 *  Note: the 'strict' flag of a reference returned by GetIdentifierReference
 *  is ignored by GetValue.  Hence we don't take a 'strict' parameter.
 *
 *  The 'throw' flag is needed for implementing 'typeof' for an unreferenced
 *  identifier.  An unreference identifier in other contexts generates a
 *  ReferenceError.
 */

DUK_LOCAL
duk_bool_t duk__getvar_helper(duk_hthread *thr,
                              duk_hobject *env,
                              duk_activation *act,
                              duk_hstring *name,
                              duk_bool_t throw_flag) {
	duk__id_lookup_result ref;
	duk_tval tv_tmp_obj;
	duk_tval tv_tmp_key;
	duk_bool_t parents;

	DUK_DDD(DUK_DDDPRINT("getvar: thr=%p, env=%p, act=%p, name=%!O "
	                     "(env -> %!dO)",
	                     (void *) thr, (void *) env, (void *) act,
	                     (duk_heaphdr *) name, (duk_heaphdr *) env));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(name != NULL);
	/* env and act may be NULL */

	DUK_STATS_INC(thr->heap, stats_getvar_all);

        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env);
        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name);

	parents = 1;     /* follow parent chain */
	if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) {
		if (ref.value) {
			duk_push_tval(thr, ref.value);
			duk_push_undefined(thr);
		} else {
			DUK_ASSERT(ref.holder != NULL);

			/* ref.holder is safe across the getprop call (even
			 * with side effects) because 'env' is reachable and
			 * ref.holder is a direct heap pointer.
			 */

			DUK_TVAL_SET_OBJECT(&tv_tmp_obj, ref.holder);
			DUK_TVAL_SET_STRING(&tv_tmp_key, name);
			(void) duk_hobject_getprop(thr, &tv_tmp_obj, &tv_tmp_key);  /* [value] */

			if (ref.has_this) {
				duk_push_hobject(thr, ref.holder);
			} else {
				duk_push_undefined(thr);
			}

			/* [value this] */
		}

		return 1;
	} else {
		if (throw_flag) {
			DUK_ERROR_FMT1(thr, DUK_ERR_REFERENCE_ERROR,
			               "identifier '%s' undefined",
			               (const char *) DUK_HSTRING_GET_DATA(name));
			DUK_WO_NORETURN(return 0;);
		}

		return 0;
	}
}

DUK_INTERNAL
duk_bool_t duk_js_getvar_envrec(duk_hthread *thr,
                                duk_hobject *env,
                                duk_hstring *name,
                                duk_bool_t throw_flag) {
	return duk__getvar_helper(thr, env, NULL, name, throw_flag);
}

DUK_INTERNAL
duk_bool_t duk_js_getvar_activation(duk_hthread *thr,
                                    duk_activation *act,
                                    duk_hstring *name,
                                    duk_bool_t throw_flag) {
	DUK_ASSERT(act != NULL);
	return duk__getvar_helper(thr, act->lex_env, act, name, throw_flag);
}

/*
 *  PUTVAR
 *
 *  See E5 Sections:
 *    11.1.2 Identifier Reference
 *    10.3.1 Identifier Resolution
 *    11.13.1 Simple Assignment  [example of where the Reference is PutValue'd]
 *    8.7.2 PutValue (V,W)  [see especially step 3.b, undefined -> automatic global in non-strict mode]
 *    8.12.4 [[CanPut]] (P)
 *    8.12.5 [[Put]] (P)
 *
 *  Note: may invalidate any valstack (or object) duk_tval pointers because
 *  putting a value may reallocate any object or any valstack.  Caller beware.
 */

DUK_LOCAL
void duk__putvar_helper(duk_hthread *thr,
                        duk_hobject *env,
                        duk_activation *act,
                        duk_hstring *name,
                        duk_tval *val,
                        duk_bool_t strict) {
	duk__id_lookup_result ref;
	duk_tval tv_tmp_obj;
	duk_tval tv_tmp_key;
	duk_bool_t parents;

	DUK_STATS_INC(thr->heap, stats_putvar_all);

	DUK_DDD(DUK_DDDPRINT("putvar: thr=%p, env=%p, act=%p, name=%!O, val=%p, strict=%ld "
	                     "(env -> %!dO, val -> %!T)",
	                     (void *) thr, (void *) env, (void *) act,
	                     (duk_heaphdr *) name, (void *) val, (long) strict,
	                     (duk_heaphdr *) env, (duk_tval *) val));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(name != NULL);
	DUK_ASSERT(val != NULL);
	/* env and act may be NULL */

        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env);
        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name);
	DUK_ASSERT_REFCOUNT_NONZERO_TVAL(val);

	/*
	 *  In strict mode E5 protects 'eval' and 'arguments' from being
	 *  assigned to (or even declared anywhere).  Attempt to do so
	 *  should result in a compile time SyntaxError.  See the internal
	 *  design documentation for details.
	 *
	 *  Thus, we should never come here, run-time, for strict code,
	 *  and name 'eval' or 'arguments'.
	 */

	DUK_ASSERT(!strict ||
	           (name != DUK_HTHREAD_STRING_EVAL(thr) &&
	            name != DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)));

	/*
	 *  Lookup variable and update in-place if found.
	 */

	parents = 1;     /* follow parent chain */

	if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) {
		if (ref.value && (ref.attrs & DUK_PROPDESC_FLAG_WRITABLE)) {
			/* Update duk_tval in-place if pointer provided and the
			 * property is writable.  If the property is not writable
			 * (immutable binding), use duk_hobject_putprop() which
			 * will respect mutability.
			 */
			duk_tval *tv_val;

			tv_val = ref.value;
			DUK_ASSERT(tv_val != NULL);
			DUK_TVAL_SET_TVAL_UPDREF(thr, tv_val, val);  /* side effects */

			/* ref.value invalidated here */
		} else {
			DUK_ASSERT(ref.holder != NULL);

			DUK_TVAL_SET_OBJECT(&tv_tmp_obj, ref.holder);
			DUK_TVAL_SET_STRING(&tv_tmp_key, name);
			(void) duk_hobject_putprop(thr, &tv_tmp_obj, &tv_tmp_key, val, strict);

			/* ref.value invalidated here */
		}

		return;
	}

	/*
	 *  Not found: write to global object (non-strict) or ReferenceError
	 *  (strict); see E5 Section 8.7.2, step 3.
	 */

	if (strict) {
		DUK_DDD(DUK_DDDPRINT("identifier binding not found, strict => reference error"));
		DUK_ERROR_FMT1(thr, DUK_ERR_REFERENCE_ERROR,
		               "identifier '%s' undefined",
		               (const char *) DUK_HSTRING_GET_DATA(name));
		DUK_WO_NORETURN(return;);
	}

	DUK_DDD(DUK_DDDPRINT("identifier binding not found, not strict => set to global"));

	DUK_TVAL_SET_OBJECT(&tv_tmp_obj, thr->builtins[DUK_BIDX_GLOBAL]);
	DUK_TVAL_SET_STRING(&tv_tmp_key, name);
	(void) duk_hobject_putprop(thr, &tv_tmp_obj, &tv_tmp_key, val, 0);  /* 0 = no throw */

	/* NB: 'val' may be invalidated here because put_value may realloc valstack,
	 * caller beware.
	 */
}

DUK_INTERNAL
void duk_js_putvar_envrec(duk_hthread *thr,
                          duk_hobject *env,
                          duk_hstring *name,
                          duk_tval *val,
                          duk_bool_t strict) {
	duk__putvar_helper(thr, env, NULL, name, val, strict);
}

DUK_INTERNAL
void duk_js_putvar_activation(duk_hthread *thr,
                              duk_activation *act,
                              duk_hstring *name,
                              duk_tval *val,
                              duk_bool_t strict) {
	DUK_ASSERT(act != NULL);
	duk__putvar_helper(thr, act->lex_env, act, name, val, strict);
}

/*
 *  DELVAR
 *
 *  See E5 Sections:
 *    11.4.1 The delete operator
 *    10.2.1.1.5 DeleteBinding (N)  [declarative environment record]
 *    10.2.1.2.5 DeleteBinding (N)  [object environment record]
 *
 *  Variable bindings established inside eval() are deletable (configurable),
 *  other bindings are not, including variables declared in global level.
 *  Registers are always non-deletable, and the deletion of other bindings
 *  is controlled by the configurable flag.
 *
 *  For strict mode code, the 'delete' operator should fail with a compile
 *  time SyntaxError if applied to identifiers.  Hence, no strict mode
 *  run-time deletion of identifiers should ever happen.  This function
 *  should never be called from strict mode code!
 */

DUK_LOCAL
duk_bool_t duk__delvar_helper(duk_hthread *thr,
                              duk_hobject *env,
                              duk_activation *act,
                              duk_hstring *name) {
	duk__id_lookup_result ref;
	duk_bool_t parents;

	DUK_DDD(DUK_DDDPRINT("delvar: thr=%p, env=%p, act=%p, name=%!O "
	                     "(env -> %!dO)",
	                     (void *) thr, (void *) env, (void *) act,
	                     (duk_heaphdr *) name, (duk_heaphdr *) env));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(name != NULL);
	/* env and act may be NULL */

        DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name);

	parents = 1;     /* follow parent chain */

	if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) {
		if (ref.value && !(ref.attrs & DUK_PROPDESC_FLAG_CONFIGURABLE)) {
			/* Identifier found in registers (always non-deletable)
			 * or declarative environment record and non-configurable.
			 */
			return 0;
		}
		DUK_ASSERT(ref.holder != NULL);

		return duk_hobject_delprop_raw(thr, ref.holder, name, 0);
	}

	/*
	 *  Not found (even in global object).
	 *
	 *  In non-strict mode this is a silent SUCCESS (!), see E5 Section 11.4.1,
	 *  step 3.b.  In strict mode this case is a compile time SyntaxError so
	 *  we should not come here.
	 */

	DUK_DDD(DUK_DDDPRINT("identifier to be deleted not found: name=%!O "
	                     "(treated as silent success)",
	                     (duk_heaphdr *) name));
	return 1;
}

#if 0  /*unused*/
DUK_INTERNAL
duk_bool_t duk_js_delvar_envrec(duk_hthread *thr,
                                duk_hobject *env,
                                duk_hstring *name) {
	return duk__delvar_helper(thr, env, NULL, name);
}
#endif

DUK_INTERNAL
duk_bool_t duk_js_delvar_activation(duk_hthread *thr,
                                    duk_activation *act,
                                    duk_hstring *name) {
	DUK_ASSERT(act != NULL);
	return duk__delvar_helper(thr, act->lex_env, act, name);
}

/*
 *  DECLVAR
 *
 *  See E5 Sections:
 *    10.4.3 Entering Function Code
 *    10.5 Declaration Binding Instantion
 *    12.2 Variable Statement
 *    11.1.2 Identifier Reference
 *    10.3.1 Identifier Resolution
 *
 *  Variable declaration behavior is mainly discussed in Section 10.5,
 *  and is not discussed in the execution semantics (Sections 11-13).
 *
 *  Conceptually declarations happen when code (global, eval, function)
 *  is entered, before any user code is executed.  In practice, register-
 *  bound identifiers are 'declared' automatically (by virtue of being
 *  allocated to registers with the initial value 'undefined').  Other
 *  identifiers are declared in the function prologue with this primitive.
 *
 *  Since non-register bindings eventually back to an internal object's
 *  properties, the 'prop_flags' argument is used to specify binding
 *  type:
 *
 *    - Immutable binding: set DUK_PROPDESC_FLAG_WRITABLE to false
 *    - Non-deletable binding: set DUK_PROPDESC_FLAG_CONFIGURABLE to false
 *    - The flag DUK_PROPDESC_FLAG_ENUMERABLE should be set, although it
 *      doesn't really matter for internal objects
 *
 *  All bindings are non-deletable mutable bindings except:
 *
 *    - Declarations in eval code (mutable, deletable)
 *    - 'arguments' binding in strict function code (immutable)
 *    - Function name binding of a function expression (immutable)
 *
 *  Declarations may go to declarative environment records (always
 *  so for functions), but may also go to object environment records
 *  (e.g. global code).  The global object environment has special
 *  behavior when re-declaring a function (but not a variable); see
 *  E5.1 specification, Section 10.5, step 5.e.
 *
 *  Declarations always go to the 'top-most' environment record, i.e.
 *  we never check the record chain.  It's not an error even if a
 *  property (even an immutable or non-deletable one) of the same name
 *  already exists.
 *
 *  If a declared variable already exists, its value needs to be updated
 *  (if possible).  Returns 1 if a PUTVAR needs to be done by the caller;
 *  otherwise returns 0.
 */

DUK_LOCAL
duk_bool_t duk__declvar_helper(duk_hthread *thr,
                               duk_hobject *env,
                               duk_hstring *name,
                               duk_tval *val,
                               duk_small_uint_t prop_flags,
                               duk_bool_t is_func_decl) {
	duk_hobject *holder;
	duk_bool_t parents;
	duk__id_lookup_result ref;
	duk_tval *tv;

	DUK_DDD(DUK_DDDPRINT("declvar: thr=%p, env=%p, name=%!O, val=%!T, prop_flags=0x%08lx, is_func_decl=%ld "
	                     "(env -> %!iO)",
	                     (void *) thr, (void *) env, (duk_heaphdr *) name,
	                     (duk_tval *) val, (unsigned long) prop_flags,
	                     (unsigned int) is_func_decl, (duk_heaphdr *) env));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(env != NULL);
	DUK_ASSERT(name != NULL);
	DUK_ASSERT(val != NULL);

	/* Note: in strict mode the compiler should reject explicit
	 * declaration of 'eval' or 'arguments'.  However, internal
	 * bytecode may declare 'arguments' in the function prologue.
	 * We don't bother checking (or asserting) for these now.
	 */

	/* Note: val is a stable duk_tval pointer.  The caller makes
	 * a value copy into its stack frame, so 'tv_val' is not subject
	 * to side effects here.
	 */

	/*
	 *  Check whether already declared.
	 *
	 *  We need to check whether the binding exists in the environment
	 *  without walking its parents.  However, we still need to check
	 *  register-bound identifiers and the prototype chain of an object
	 *  environment target object.
	 */

	parents = 0;  /* just check 'env' */
	if (duk__get_identifier_reference(thr, env, name, NULL, parents, &ref)) {
		duk_int_t e_idx;
		duk_int_t h_idx;
		duk_small_uint_t flags;

		/*
		 *  Variable already declared, ignore re-declaration.
		 *  The only exception is the updated behavior of E5.1 for
		 *  global function declarations, E5.1 Section 10.5, step 5.e.
		 *  This behavior does not apply to global variable declarations.
		 */

		if (!(is_func_decl && env == thr->builtins[DUK_BIDX_GLOBAL_ENV])) {
			DUK_DDD(DUK_DDDPRINT("re-declare a binding, ignoring"));
			return 1;  /* 1 -> needs a PUTVAR */
		}

		/*
		 *  Special behavior in E5.1.
		 *
		 *  Note that even though parents == 0, the conflicting property
		 *  may be an inherited property (currently our global object's
		 *  prototype is Object.prototype).  Step 5.e first operates on
		 *  the existing property (which is potentially in an ancestor)
		 *  and then defines a new property in the global object (and
		 *  never modifies the ancestor).
		 *
		 *  Also note that this logic would become even more complicated
		 *  if the conflicting property might be a virtual one.  Object
		 *  prototype has no virtual properties, though.
		 *
		 *  XXX: this is now very awkward, rework.
		 */

		DUK_DDD(DUK_DDDPRINT("re-declare a function binding in global object, "
		                     "updated E5.1 processing"));

		DUK_ASSERT(ref.holder != NULL);
		holder = ref.holder;

		/* holder will be set to the target object, not the actual object
		 * where the property was found (see duk__get_identifier_reference()).
		 */
		DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(holder) == DUK_HOBJECT_CLASS_GLOBAL);
		DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(holder));  /* global object doesn't have array part */

		/* XXX: use a helper for prototype traversal; no loop check here */
		/* must be found: was found earlier, and cannot be inherited */
		for (;;) {
			DUK_ASSERT(holder != NULL);
			if (duk_hobject_find_entry(thr->heap, holder, name, &e_idx, &h_idx)) {
				DUK_ASSERT(e_idx >= 0);
				break;
			}
			/* SCANBUILD: NULL pointer dereference, doesn't actually trigger,
			 * asserted above.
			 */
			holder = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, holder);
		}
		DUK_ASSERT(holder != NULL);
		DUK_ASSERT(e_idx >= 0);
		/* SCANBUILD: scan-build produces a NULL pointer dereference warning
		 * below; it never actually triggers because holder is actually never
		 * NULL.
		 */

		/* ref.holder is global object, holder is the object with the
		 * conflicting property.
		 */

		flags = DUK_HOBJECT_E_GET_FLAGS(thr->heap, holder, e_idx);
		if (!(flags & DUK_PROPDESC_FLAG_CONFIGURABLE)) {
			if (flags & DUK_PROPDESC_FLAG_ACCESSOR) {
				DUK_DDD(DUK_DDDPRINT("existing property is a non-configurable "
				                     "accessor -> reject"));
				goto fail_existing_attributes;
			}
			if (!((flags & DUK_PROPDESC_FLAG_WRITABLE) &&
			      (flags & DUK_PROPDESC_FLAG_ENUMERABLE))) {
				DUK_DDD(DUK_DDDPRINT("existing property is a non-configurable "
				                     "plain property which is not writable and "
				                     "enumerable -> reject"));
				goto fail_existing_attributes;
			}

			DUK_DDD(DUK_DDDPRINT("existing property is not configurable but "
			                     "is plain, enumerable, and writable -> "
			                     "allow redeclaration"));
		}

		if (holder == ref.holder) {
			/* XXX: if duk_hobject_define_property_internal() was updated
			 * to handle a pre-existing accessor property, this would be
			 * a simple call (like for the ancestor case).
			 */
			DUK_DDD(DUK_DDDPRINT("redefine, offending property in global object itself"));

			if (flags & DUK_PROPDESC_FLAG_ACCESSOR) {
				duk_hobject *tmp;

				tmp = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, holder, e_idx);
				DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, holder, e_idx, NULL);
				DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
				DUK_UNREF(tmp);
				tmp = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, holder, e_idx);
				DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, holder, e_idx, NULL);
				DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
				DUK_UNREF(tmp);
			} else {
				tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx);
				DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv);
			}

			/* Here val would be potentially invalid if we didn't make
			 * a value copy at the caller.
			 */

			tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx);
			DUK_TVAL_SET_TVAL(tv, val);
			DUK_TVAL_INCREF(thr, tv);
			DUK_HOBJECT_E_SET_FLAGS(thr->heap, holder, e_idx, prop_flags);

			DUK_DDD(DUK_DDDPRINT("updated global binding, final result: "
			                     "value -> %!T, prop_flags=0x%08lx",
			                     (duk_tval *) DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx),
			                     (unsigned long) prop_flags));
		} else {
			DUK_DDD(DUK_DDDPRINT("redefine, offending property in ancestor"));

			DUK_ASSERT(ref.holder == thr->builtins[DUK_BIDX_GLOBAL]);
			duk_push_tval(thr, val);
			duk_hobject_define_property_internal(thr, ref.holder, name, prop_flags);
		}

		return 0;
	}

	/*
	 *  Not found (in registers or record objects).  Declare
	 *  to current variable environment.
	 */

	/*
	 *  Get holder object
	 */

	if (DUK_HOBJECT_IS_DECENV(env)) {
		DUK_HDECENV_ASSERT_VALID((duk_hdecenv *) env);
		holder = env;
	} else {
		DUK_HOBJENV_ASSERT_VALID((duk_hobjenv *) env);
		holder = ((duk_hobjenv *) env)->target;
		DUK_ASSERT(holder != NULL);
	}

	/*
	 *  Define new property
	 *
	 *  Note: this may fail if the holder is not extensible.
	 */

	/* XXX: this is awkward as we use an internal method which doesn't handle
	 * extensibility etc correctly.  Basically we'd want to do a [[DefineOwnProperty]]
	 * or Object.defineProperty() here.
	 */

	if (!DUK_HOBJECT_HAS_EXTENSIBLE(holder)) {
		goto fail_not_extensible;
	}

	duk_push_hobject(thr, holder);
	duk_push_hstring(thr, name);
	duk_push_tval(thr, val);
	duk_xdef_prop(thr, -3, prop_flags);  /* [holder name val] -> [holder] */
	duk_pop_unsafe(thr);

	return 0;

 fail_existing_attributes:
 fail_not_extensible:
	DUK_ERROR_TYPE(thr, "declaration failed");
	DUK_WO_NORETURN(return 0;);
}

DUK_INTERNAL
duk_bool_t duk_js_declvar_activation(duk_hthread *thr,
                                     duk_activation *act,
                                     duk_hstring *name,
                                     duk_tval *val,
                                     duk_small_uint_t prop_flags,
                                     duk_bool_t is_func_decl) {
	duk_hobject *env;
	duk_tval tv_val_copy;

	DUK_ASSERT(act != NULL);

	/*
	 *  Make a value copy of the input val.  This ensures that
	 *  side effects cannot invalidate the pointer.
	 */

	DUK_TVAL_SET_TVAL(&tv_val_copy, val);
	val = &tv_val_copy;

	/*
	 *  Delayed env creation check
	 */

	if (!act->var_env) {
		DUK_ASSERT(act->lex_env == NULL);
		duk_js_init_activation_environment_records_delayed(thr, act);
		/* 'act' is a stable pointer, so still OK. */
	}
	DUK_ASSERT(act->lex_env != NULL);
	DUK_ASSERT(act->var_env != NULL);

	env = act->var_env;
	DUK_ASSERT(env != NULL);
	DUK_ASSERT(DUK_HOBJECT_IS_ENV(env));

	return duk__declvar_helper(thr, env, name, val, prop_flags, is_func_decl);
}
/*
 *  Lexer for source files, ToNumber() string conversions, RegExp expressions,
 *  and JSON.
 *
 *  Provides a stream of ECMAScript tokens from an UTF-8/CESU-8 buffer.  The
 *  caller can also rewind the token stream into a certain position which is
 *  needed by the compiler part for multi-pass scanning.  Tokens are
 *  represented as duk_token structures, and contain line number information.
 *  Token types are identified with DUK_TOK_* defines.
 *
 *  Characters are decoded into a fixed size lookup window consisting of
 *  decoded Unicode code points, with window positions past the end of the
 *  input filled with an invalid codepoint (-1).  The tokenizer can thus
 *  perform multiple character lookups efficiently and with few sanity
 *  checks (such as access outside the end of the input), which keeps the
 *  tokenization code small at the cost of performance.
 *
 *  Character data in tokens, such as identifier names and string literals,
 *  is encoded into CESU-8 format on-the-fly while parsing the token in
 *  question.  The string data is made reachable to garbage collection by
 *  placing the token-related values in value stack entries allocated for
 *  this purpose by the caller.  The characters exist in Unicode code point
 *  form only in the fixed size lookup window, which keeps character data
 *  expansion (of especially ASCII data) low.
 *
 *  Token parsing supports the full range of Unicode characters as described
 *  in the E5 specification.  Parsing has been optimized for ASCII characters
 *  because ordinary ECMAScript code consists almost entirely of ASCII
 *  characters.  Matching of complex Unicode codepoint sets (such as in the
 *  IdentifierStart and IdentifierPart productions) is optimized for size,
 *  and is done using a linear scan of a bit-packed list of ranges.  This is
 *  very slow, but should never be entered unless the source code actually
 *  contains Unicode characters.
 *
 *  ECMAScript tokenization is partially context sensitive.  First,
 *  additional future reserved words are recognized in strict mode (see E5
 *  Section 7.6.1.2).  Second, a forward slash character ('/') can be
 *  recognized either as starting a RegExp literal or as a division operator,
 *  depending on context.  The caller must provide necessary context flags
 *  when requesting a new token.
 *
 *  Future work:
 *
 *    * Make line number tracking optional, as it consumes space.
 *
 *    * Add a feature flag for disabling UTF-8 decoding of input, as most
 *      source code is ASCII.  Because of Unicode escapes written in ASCII,
 *      this does not allow Unicode support to be removed from e.g.
 *      duk_unicode_is_identifier_start() nor does it allow removal of CESU-8
 *      encoding of e.g. string literals.
 *
 *    * Add a feature flag for disabling Unicode compliance of e.g. identifier
 *      names.  This allows for a build more than a kilobyte smaller, because
 *      Unicode ranges needed by duk_unicode_is_identifier_start() and
 *      duk_unicode_is_identifier_part() can be dropped.  String literals
 *      should still be allowed to contain escaped Unicode, so this still does
 *      not allow removal of CESU-8 encoding of e.g. string literals.
 *
 *    * Character lookup tables for codepoints above BMP could be stripped.
 *
 *    * Strictly speaking, E5 specification requires that source code consists
 *      of 16-bit code units, and if not, must be conceptually converted to
 *      that format first.  The current lexer processes Unicode code points
 *      and allows characters outside the BMP.  These should be converted to
 *      surrogate pairs while reading the source characters into the window,
 *      not after tokens have been formed (as is done now).  However, the fix
 *      is not trivial because two characters are decoded from one codepoint.
 *
 *    * Optimize for speed as well as size.  Large if-else ladders are (at
 *      least potentially) slow.
 */

/* #include duk_internal.h -> already included */

/*
 *  Various defines and file specific helper macros
 */

#define DUK__MAX_RE_DECESC_DIGITS     9
#define DUK__MAX_RE_QUANT_DIGITS      9   /* Does not allow e.g. 2**31-1, but one more would allow overflows of u32. */

/* whether to use macros or helper function depends on call count */
#define DUK__ISDIGIT(x)          ((x) >= DUK_ASC_0 && (x) <= DUK_ASC_9)
#define DUK__ISHEXDIGIT(x)       duk__is_hex_digit((x))
#define DUK__ISOCTDIGIT(x)       ((x) >= DUK_ASC_0 && (x) <= DUK_ASC_7)
#define DUK__ISDIGIT03(x)        ((x) >= DUK_ASC_0 && (x) <= DUK_ASC_3)
#define DUK__ISDIGIT47(x)        ((x) >= DUK_ASC_4 && (x) <= DUK_ASC_7)

/* lexer character window helpers */
#define DUK__LOOKUP(lex_ctx,idx)            ((lex_ctx)->window[(idx)].codepoint)
#define DUK__ADVANCECHARS(lex_ctx,count)    duk__advance_chars((lex_ctx), (count))
#define DUK__ADVANCEBYTES(lex_ctx,count)    duk__advance_bytes((lex_ctx), (count))
#define DUK__INITBUFFER(lex_ctx)            duk__initbuffer((lex_ctx))
#define DUK__APPENDBUFFER(lex_ctx,x)        duk__appendbuffer((lex_ctx), (duk_codepoint_t) (x))
#define DUK__APPENDBUFFER_ASCII(lex_ctx,x)  duk__appendbuffer_ascii((lex_ctx), (duk_codepoint_t) (x))

/* lookup shorthands (note: assume context variable is named 'lex_ctx') */
#define DUK__L0()  DUK__LOOKUP(lex_ctx, 0)
#define DUK__L1()  DUK__LOOKUP(lex_ctx, 1)
#define DUK__L2()  DUK__LOOKUP(lex_ctx, 2)
#define DUK__L3()  DUK__LOOKUP(lex_ctx, 3)
#define DUK__L4()  DUK__LOOKUP(lex_ctx, 4)
#define DUK__L5()  DUK__LOOKUP(lex_ctx, 5)

/* packed advance/token number macro used by multiple functions */
#define DUK__ADVTOK(advbytes,tok)  ((((advbytes) * sizeof(duk_lexer_codepoint)) << 8) + (tok))

/*
 *  Advance lookup window by N characters, filling in new characters as
 *  necessary.  After returning caller is guaranteed a character window of
 *  at least DUK_LEXER_WINDOW_SIZE characters.
 *
 *  The main function duk__advance_bytes() is called at least once per every
 *  token so it has a major lexer/compiler performance impact.  There are two
 *  variants for the main duk__advance_bytes() algorithm: a sliding window
 *  approach which is slightly faster at the cost of larger code footprint,
 *  and a simple copying one.
 *
 *  Decoding directly from the source string would be another lexing option.
 *  But the lookup window based approach has the advantage of hiding the
 *  source string and its encoding effectively which gives more flexibility
 *  going forward to e.g. support chunked streaming of source from flash.
 *
 *  Decodes UTF-8/CESU-8 leniently with support for code points from U+0000 to
 *  U+10FFFF, causing an error if the input is unparseable.  Leniency means:
 *
 *    * Unicode code point validation is intentionally not performed,
 *      except to check that the codepoint does not exceed 0x10ffff.
 *
 *    * In particular, surrogate pairs are allowed and not combined, which
 *      allows source files to represent all SourceCharacters with CESU-8.
 *      Broken surrogate pairs are allowed, as ECMAScript does not mandate
 *      their validation.
 *
 *    * Allow non-shortest UTF-8 encodings.
 *
 *  Leniency here causes few security concerns because all character data is
 *  decoded into Unicode codepoints before lexer processing, and is then
 *  re-encoded into CESU-8.  The source can be parsed as strict UTF-8 with
 *  a compiler option.  However, ECMAScript source characters include -all-
 *  16-bit unsigned integer codepoints, so leniency seems to be appropriate.
 *
 *  Note that codepoints above the BMP are not strictly SourceCharacters,
 *  but the lexer still accepts them as such.  Before ending up in a string
 *  or an identifier name, codepoints above BMP are converted into surrogate
 *  pairs and then CESU-8 encoded, resulting in 16-bit Unicode data as
 *  expected by ECMAScript.
 *
 *  An alternative approach to dealing with invalid or partial sequences
 *  would be to skip them and replace them with e.g. the Unicode replacement
 *  character U+FFFD.  This has limited utility because a replacement character
 *  will most likely cause a parse error, unless it occurs inside a string.
 *  Further, ECMAScript source is typically pure ASCII.
 *
 *  See:
 *
 *     http://en.wikipedia.org/wiki/UTF-8
 *     http://en.wikipedia.org/wiki/CESU-8
 *     http://tools.ietf.org/html/rfc3629
 *     http://en.wikipedia.org/wiki/UTF-8#Invalid_byte_sequences
 *
 *  Future work:
 *
 *    * Reject other invalid Unicode sequences (see Wikipedia entry for examples)
 *      in strict UTF-8 mode.
 *
 *    * Size optimize.  An attempt to use a 16-byte lookup table for the first
 *      byte resulted in a code increase though.
 *
 *    * Is checking against maximum 0x10ffff really useful?  4-byte encoding
 *      imposes a certain limit anyway.
 *
 *    * Support chunked streaming of source code.  Can be implemented either
 *      by streaming chunks of bytes or chunks of codepoints.
 */

#if defined(DUK_USE_LEXER_SLIDING_WINDOW)
DUK_LOCAL void duk__fill_lexer_buffer(duk_lexer_ctx *lex_ctx, duk_small_uint_t start_offset_bytes) {
	duk_lexer_codepoint *cp, *cp_end;
	duk_ucodepoint_t x;
	duk_small_uint_t contlen;
	const duk_uint8_t *p, *p_end;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
	duk_ucodepoint_t mincp;
#endif
	duk_int_t input_line;

	/* Use temporaries and update lex_ctx only when finished. */
	input_line = lex_ctx->input_line;
	p = lex_ctx->input + lex_ctx->input_offset;
	p_end = lex_ctx->input + lex_ctx->input_length;

	cp = (duk_lexer_codepoint *) (void *) ((duk_uint8_t *) lex_ctx->buffer + start_offset_bytes);
	cp_end = lex_ctx->buffer + DUK_LEXER_BUFFER_SIZE;

	for (; cp != cp_end; cp++) {
		cp->offset = (duk_size_t) (p - lex_ctx->input);
		cp->line = input_line;

		/* XXX: potential issue with signed pointers, p_end < p. */
		if (DUK_UNLIKELY(p >= p_end)) {
			/* If input_offset were assigned a negative value, it would
			 * result in a large positive value.  Most likely it would be
			 * larger than input_length and be caught here.  In any case
			 * no memory unsafe behavior would happen.
			 */
			cp->codepoint = -1;
			continue;
		}

		x = (duk_ucodepoint_t) (*p++);

		/* Fast path. */

		if (DUK_LIKELY(x < 0x80UL)) {
			DUK_ASSERT(x != 0x2028UL && x != 0x2029UL);  /* not LS/PS */
			if (DUK_UNLIKELY(x <= 0x000dUL)) {
				if ((x == 0x000aUL) ||
				    ((x == 0x000dUL) && (p >= p_end || *p != 0x000aUL))) {
					/* lookup for 0x000a above assumes shortest encoding now */

					/* E5 Section 7.3, treat the following as newlines:
					 *   LF
					 *   CR [not followed by LF]
					 *   LS
					 *   PS
					 *
					 * For CR LF, CR is ignored if it is followed by LF, and the LF will bump
					 * the line number.
					 */
					input_line++;
				}
			}

			cp->codepoint = (duk_codepoint_t) x;
			continue;
		}

		/* Slow path. */

		if (x < 0xc0UL) {
			/* 10xx xxxx -> invalid */
			goto error_encoding;
		} else if (x < 0xe0UL) {
			/* 110x xxxx   10xx xxxx  */
			contlen = 1;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
			mincp = 0x80UL;
#endif
			x = x & 0x1fUL;
		} else if (x < 0xf0UL) {
			/* 1110 xxxx   10xx xxxx   10xx xxxx */
			contlen = 2;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
			mincp = 0x800UL;
#endif
			x = x & 0x0fUL;
		} else if (x < 0xf8UL) {
			/* 1111 0xxx   10xx xxxx   10xx xxxx   10xx xxxx */
			contlen = 3;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
			mincp = 0x10000UL;
#endif
			x = x & 0x07UL;
		} else {
			/* no point in supporting encodings of 5 or more bytes */
			goto error_encoding;
		}

		DUK_ASSERT(p_end >= p);
		if ((duk_size_t) contlen > (duk_size_t) (p_end - p)) {
			goto error_clipped;
		}

		while (contlen > 0) {
			duk_small_uint_t y;
			y = *p++;
			if ((y & 0xc0U) != 0x80U) {
				/* check that byte has the form 10xx xxxx */
				goto error_encoding;
			}
			x = x << 6;
			x += y & 0x3fUL;
			contlen--;
		}

		/* check final character validity */

		if (x > 0x10ffffUL) {
			goto error_encoding;
		}
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
		if (x < mincp || (x >= 0xd800UL && x <= 0xdfffUL) || x == 0xfffeUL) {
			goto error_encoding;
		}
#endif

		DUK_ASSERT(x != 0x000aUL && x != 0x000dUL);
		if ((x == 0x2028UL) || (x == 0x2029UL)) {
			input_line++;
		}

		cp->codepoint = (duk_codepoint_t) x;
	}

	lex_ctx->input_offset = (duk_size_t) (p - lex_ctx->input);
	lex_ctx->input_line = input_line;
	return;

 error_clipped:   /* clipped codepoint */
 error_encoding:  /* invalid codepoint encoding or codepoint */
	lex_ctx->input_offset = (duk_size_t) (p - lex_ctx->input);
	lex_ctx->input_line = input_line;

	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_SOURCE_DECODE_FAILED);
	DUK_WO_NORETURN(return;);
}

DUK_LOCAL void duk__advance_bytes(duk_lexer_ctx *lex_ctx, duk_small_uint_t count_bytes) {
	duk_small_uint_t used_bytes, avail_bytes;

	DUK_ASSERT_DISABLE(count_bytes >= 0);  /* unsigned */
	DUK_ASSERT(count_bytes <= (duk_small_uint_t) (DUK_LEXER_WINDOW_SIZE * sizeof(duk_lexer_codepoint)));
	DUK_ASSERT(lex_ctx->window >= lex_ctx->buffer);
	DUK_ASSERT(lex_ctx->window < lex_ctx->buffer + DUK_LEXER_BUFFER_SIZE);
	DUK_ASSERT((duk_uint8_t *) lex_ctx->window + count_bytes <= (duk_uint8_t *) lex_ctx->buffer + DUK_LEXER_BUFFER_SIZE * sizeof(duk_lexer_codepoint));

	/* Zero 'count' is also allowed to make call sites easier.
	 * Arithmetic in bytes generates better code in GCC.
	 */

	lex_ctx->window = (duk_lexer_codepoint *) (void *) ((duk_uint8_t *) lex_ctx->window + count_bytes);  /* avoid multiply */
	used_bytes = (duk_small_uint_t) ((duk_uint8_t *) lex_ctx->window - (duk_uint8_t *) lex_ctx->buffer);
	avail_bytes = DUK_LEXER_BUFFER_SIZE * sizeof(duk_lexer_codepoint) - used_bytes;
	if (avail_bytes < (duk_small_uint_t) (DUK_LEXER_WINDOW_SIZE * sizeof(duk_lexer_codepoint))) {
		/* Not enough data to provide a full window, so "scroll" window to
		 * start of buffer and fill up the rest.
		 */
		duk_memmove((void *) lex_ctx->buffer,
		            (const void *) lex_ctx->window,
		            (size_t) avail_bytes);
		lex_ctx->window = lex_ctx->buffer;
		duk__fill_lexer_buffer(lex_ctx, avail_bytes);
	}
}

DUK_LOCAL void duk__init_lexer_window(duk_lexer_ctx *lex_ctx) {
	lex_ctx->window = lex_ctx->buffer;
	duk__fill_lexer_buffer(lex_ctx, 0);
}
#else  /* DUK_USE_LEXER_SLIDING_WINDOW */
DUK_LOCAL duk_codepoint_t duk__read_char(duk_lexer_ctx *lex_ctx) {
	duk_ucodepoint_t x;
	duk_small_uint_t len;
	duk_small_uint_t i;
	const duk_uint8_t *p;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
	duk_ucodepoint_t mincp;
#endif
	duk_size_t input_offset;

	input_offset = lex_ctx->input_offset;
	if (DUK_UNLIKELY(input_offset >= lex_ctx->input_length)) {
		/* If input_offset were assigned a negative value, it would
		 * result in a large positive value.  Most likely it would be
		 * larger than input_length and be caught here.  In any case
		 * no memory unsafe behavior would happen.
		 */
		return -1;
	}

	p = lex_ctx->input + input_offset;
	x = (duk_ucodepoint_t) (*p);

	if (DUK_LIKELY(x < 0x80UL)) {
		/* 0xxx xxxx -> fast path */

		/* input offset tracking */
		lex_ctx->input_offset++;

		DUK_ASSERT(x != 0x2028UL && x != 0x2029UL);  /* not LS/PS */
		if (DUK_UNLIKELY(x <= 0x000dUL)) {
			if ((x == 0x000aUL) ||
			    ((x == 0x000dUL) && (lex_ctx->input_offset >= lex_ctx->input_length ||
			                         lex_ctx->input[lex_ctx->input_offset] != 0x000aUL))) {
				/* lookup for 0x000a above assumes shortest encoding now */

				/* E5 Section 7.3, treat the following as newlines:
				 *   LF
				 *   CR [not followed by LF]
				 *   LS
				 *   PS
				 *
				 * For CR LF, CR is ignored if it is followed by LF, and the LF will bump
				 * the line number.
				 */
				lex_ctx->input_line++;
			}
		}

		return (duk_codepoint_t) x;
	}

	/* Slow path. */

	if (x < 0xc0UL) {
		/* 10xx xxxx -> invalid */
		goto error_encoding;
	} else if (x < 0xe0UL) {
		/* 110x xxxx   10xx xxxx  */
		len = 2;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
		mincp = 0x80UL;
#endif
		x = x & 0x1fUL;
	} else if (x < 0xf0UL) {
		/* 1110 xxxx   10xx xxxx   10xx xxxx */
		len = 3;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
		mincp = 0x800UL;
#endif
		x = x & 0x0fUL;
	} else if (x < 0xf8UL) {
		/* 1111 0xxx   10xx xxxx   10xx xxxx   10xx xxxx */
		len = 4;
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
		mincp = 0x10000UL;
#endif
		x = x & 0x07UL;
	} else {
		/* no point in supporting encodings of 5 or more bytes */
		goto error_encoding;
	}

	DUK_ASSERT(lex_ctx->input_length >= lex_ctx->input_offset);
	if ((duk_size_t) len > (duk_size_t) (lex_ctx->input_length - lex_ctx->input_offset)) {
		goto error_clipped;
	}

	p++;
	for (i = 1; i < len; i++) {
		duk_small_uint_t y;
		y = *p++;
		if ((y & 0xc0U) != 0x80U) {
			/* check that byte has the form 10xx xxxx */
			goto error_encoding;
		}
		x = x << 6;
		x += y & 0x3fUL;
	}

	/* check final character validity */

	if (x > 0x10ffffUL) {
		goto error_encoding;
	}
#if defined(DUK_USE_STRICT_UTF8_SOURCE)
	if (x < mincp || (x >= 0xd800UL && x <= 0xdfffUL) || x == 0xfffeUL) {
		goto error_encoding;
	}
#endif

	/* input offset tracking */
	lex_ctx->input_offset += len;

	/* line tracking */
	DUK_ASSERT(x != 0x000aUL && x != 0x000dUL);
	if ((x == 0x2028UL) || (x == 0x2029UL)) {
		lex_ctx->input_line++;
	}

	return (duk_codepoint_t) x;

 error_clipped:   /* clipped codepoint */
 error_encoding:  /* invalid codepoint encoding or codepoint */
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_SOURCE_DECODE_FAILED);
	DUK_WO_NORETURN(return 0;);
}

DUK_LOCAL void duk__advance_bytes(duk_lexer_ctx *lex_ctx, duk_small_uint_t count_bytes) {
	duk_small_uint_t keep_bytes;
	duk_lexer_codepoint *cp, *cp_end;

	DUK_ASSERT_DISABLE(count_bytes >= 0);  /* unsigned */
	DUK_ASSERT(count_bytes <= (duk_small_uint_t) (DUK_LEXER_WINDOW_SIZE * sizeof(duk_lexer_codepoint)));

	/* Zero 'count' is also allowed to make call sites easier. */

	keep_bytes = DUK_LEXER_WINDOW_SIZE * sizeof(duk_lexer_codepoint) - count_bytes;
	duk_memmove((void *) lex_ctx->window,
	            (const void *) ((duk_uint8_t *) lex_ctx->window + count_bytes),
	            (size_t) keep_bytes);

	cp = (duk_lexer_codepoint *) ((duk_uint8_t *) lex_ctx->window + keep_bytes);
	cp_end = lex_ctx->window + DUK_LEXER_WINDOW_SIZE;
	for (; cp != cp_end; cp++) {
		cp->offset = lex_ctx->input_offset;
		cp->line = lex_ctx->input_line;
		cp->codepoint = duk__read_char(lex_ctx);
	}
}

DUK_LOCAL void duk__init_lexer_window(duk_lexer_ctx *lex_ctx) {
	/* Call with count == DUK_LEXER_WINDOW_SIZE to fill buffer initially. */
	duk__advance_bytes(lex_ctx, DUK_LEXER_WINDOW_SIZE * sizeof(duk_lexer_codepoint));  /* fill window */
}
#endif  /* DUK_USE_LEXER_SLIDING_WINDOW */

DUK_LOCAL void duk__advance_chars(duk_lexer_ctx *lex_ctx, duk_small_uint_t count_chars) {
	duk__advance_bytes(lex_ctx, count_chars * sizeof(duk_lexer_codepoint));
}

/*
 *  (Re)initialize the temporary byte buffer.  May be called extra times
 *  with little impact.
 */

DUK_LOCAL void duk__initbuffer(duk_lexer_ctx *lex_ctx) {
	/* Reuse buffer as is unless buffer has grown large. */
	if (DUK_HBUFFER_DYNAMIC_GET_SIZE(lex_ctx->buf) < DUK_LEXER_TEMP_BUF_LIMIT) {
		/* Keep current size */
	} else {
		duk_hbuffer_resize(lex_ctx->thr, lex_ctx->buf, DUK_LEXER_TEMP_BUF_LIMIT);
	}

	DUK_BW_INIT_WITHBUF(lex_ctx->thr, &lex_ctx->bw, lex_ctx->buf);
}

/*
 *  Append a Unicode codepoint to the temporary byte buffer.  Performs
 *  CESU-8 surrogate pair encoding for codepoints above the BMP.
 *  Existing surrogate pairs are allowed and also encoded into CESU-8.
 */

DUK_LOCAL void duk__appendbuffer(duk_lexer_ctx *lex_ctx, duk_codepoint_t x) {
	/*
	 *  Since character data is only generated by decoding the source or by
	 *  the compiler itself, we rely on the input codepoints being correct
	 *  and avoid a check here.
	 *
	 *  Character data can also come here through decoding of Unicode
	 *  escapes ("\udead\ubeef") so all 16-but unsigned values can be
	 *  present, even when the source file itself is strict UTF-8.
	 */
	DUK_ASSERT(x >= 0 && x <= 0x10ffffL);

	DUK_BW_WRITE_ENSURE_CESU8(lex_ctx->thr, &lex_ctx->bw, (duk_ucodepoint_t) x);
}

DUK_LOCAL void duk__appendbuffer_ascii(duk_lexer_ctx *lex_ctx, duk_codepoint_t x) {
	/* ASCII characters can be emitted as a single byte without encoding
	 * which matters for some fast paths.
	 */
	DUK_ASSERT(x >= 0 && x <= 0x7f);

	DUK_BW_WRITE_ENSURE_U8(lex_ctx->thr, &lex_ctx->bw, (duk_uint8_t) x);
}

/*
 *  Intern the temporary byte buffer into a valstack slot
 *  (in practice, slot1 or slot2).
 */

DUK_LOCAL duk_hstring *duk__internbuffer(duk_lexer_ctx *lex_ctx, duk_idx_t valstack_idx) {
	DUK_ASSERT(valstack_idx == lex_ctx->slot1_idx || valstack_idx == lex_ctx->slot2_idx);

	DUK_BW_PUSH_AS_STRING(lex_ctx->thr, &lex_ctx->bw);
	duk_replace(lex_ctx->thr, valstack_idx);
	return duk_known_hstring(lex_ctx->thr, valstack_idx);
}

/*
 *  Init lexer context
 */

DUK_INTERNAL void duk_lexer_initctx(duk_lexer_ctx *lex_ctx) {
	DUK_ASSERT(lex_ctx != NULL);

	duk_memzero(lex_ctx, sizeof(*lex_ctx));
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
#if defined(DUK_USE_LEXER_SLIDING_WINDOW)
	lex_ctx->window = NULL;
#endif
	lex_ctx->thr = NULL;
	lex_ctx->input = NULL;
	lex_ctx->buf = NULL;
#endif
}

/*
 *  Set lexer input position and reinitialize lookup window.
 */

DUK_INTERNAL void duk_lexer_getpoint(duk_lexer_ctx *lex_ctx, duk_lexer_point *pt) {
	pt->offset = lex_ctx->window[0].offset;
	pt->line = lex_ctx->window[0].line;
}

DUK_INTERNAL void duk_lexer_setpoint(duk_lexer_ctx *lex_ctx, duk_lexer_point *pt) {
	DUK_ASSERT_DISABLE(pt->offset >= 0);  /* unsigned */
	DUK_ASSERT(pt->line >= 1);
	lex_ctx->input_offset = pt->offset;
	lex_ctx->input_line = pt->line;
	duk__init_lexer_window(lex_ctx);
}

/*
 *  Lexing helpers
 */

/* Numeric value of a hex digit (also covers octal and decimal digits) or
 * -1 if not a valid hex digit.
 */
DUK_LOCAL duk_codepoint_t duk__hexval_validate(duk_codepoint_t x) {
	duk_small_int_t t;

	/* Here 'x' is a Unicode codepoint */
	if (DUK_LIKELY(x >= 0 && x <= 0xff)) {
		t = duk_hex_dectab[x];
		if (DUK_LIKELY(t >= 0)) {
			return t;
		}
	}

	return -1;
}

/* Just a wrapper for call sites where 'x' is known to be valid so
 * we assert for it before decoding.
 */
DUK_LOCAL duk_codepoint_t duk__hexval(duk_codepoint_t x) {
	duk_codepoint_t ret;

	DUK_ASSERT((x >= DUK_ASC_0 && x <= DUK_ASC_9) ||
	           (x >= DUK_ASC_LC_A && x <= DUK_ASC_LC_F) ||
	           (x >= DUK_ASC_UC_A && x <= DUK_ASC_UC_F));
	ret = duk__hexval_validate(x);
	DUK_ASSERT(ret >= 0 && ret <= 15);
	return ret;
}

/* having this as a separate function provided a size benefit */
DUK_LOCAL duk_bool_t duk__is_hex_digit(duk_codepoint_t x) {
	if (DUK_LIKELY(x >= 0 && x <= 0xff)) {
		return (duk_hex_dectab[x] >= 0);
	}
	return 0;
}

/* Parse a Unicode escape of the form \xHH, \uHHHH, or \u{H+}.  Shared by
 * source and RegExp parsing.
 */
DUK_LOCAL duk_codepoint_t duk__lexer_parse_escape(duk_lexer_ctx *lex_ctx, duk_bool_t allow_es6) {
	duk_small_int_t digits;  /* Initial value 2 or 4 for fixed length escapes, 0 for ES2015 \u{H+}. */
	duk_codepoint_t escval;
	duk_codepoint_t x;
	duk_small_uint_t adv;

	DUK_ASSERT(DUK__L0() == DUK_ASC_BACKSLASH);  /* caller responsibilities */
	DUK_ASSERT(DUK__L1() == DUK_ASC_LC_X || DUK__L1() == DUK_ASC_LC_U);
	DUK_UNREF(allow_es6);

	adv = 2;
	digits = 2;
	if (DUK__L1() == DUK_ASC_LC_U) {
		digits = 4;
#if defined(DUK_USE_ES6_UNICODE_ESCAPE)
		if (DUK__L2() == DUK_ASC_LCURLY && allow_es6) {
			digits = 0;
			adv = 3;
		}
#endif
	}
	DUK__ADVANCECHARS(lex_ctx, adv);

	escval = 0;
	for (;;) {
		/* One of the escape forms: \xHH, \uHHHH, \u{H+}.
		 * The 'digits' variable tracks parsing state and is
		 * initialized to:
		 *
		 *   \xHH     2
		 *   \uHH     4
		 *   \u{H+}   0 first time, updated to -1 to indicate
		 *            at least one digit has been parsed
		 *
		 * Octal parsing is handled separately because it can be
		 * done with fixed lookahead and also has validation
		 * rules which depend on the escape length (which is
		 * variable).
		 *
		 * We don't need a specific check for x < 0 (end of
		 * input) or duk_unicode_is_line_terminator(x)
		 * because the 'dig' decode will fail and lead to a
		 * SyntaxError.
		 */
		duk_codepoint_t dig;

		x = DUK__L0();
		DUK__ADVANCECHARS(lex_ctx, 1);

		dig = duk__hexval_validate(x);
		if (digits > 0) {
			digits--;
			if (dig < 0) {
				goto fail_escape;
			}
			DUK_ASSERT(dig >= 0x00 && dig <= 0x0f);
			escval = (escval << 4) + dig;
			if (digits == 0) {
				DUK_ASSERT(escval >= 0 && escval <= 0xffffL);
				break;
			}
		} else {
#if defined(DUK_USE_ES6_UNICODE_ESCAPE)
			DUK_ASSERT(digits == 0 /* first time */ || digits == -1 /* others */);
			if (dig >= 0) {
				DUK_ASSERT(dig >= 0x00 && dig <= 0x0f);
				escval = (escval << 4) + dig;
				if (escval > 0x10ffffL) {
					goto fail_escape;
				}
			} else if (x == DUK_ASC_RCURLY) {
				if (digits == 0) {
					/* Empty escape, \u{}. */
					goto fail_escape;
				}
				DUK_ASSERT(escval >= 0 && escval <= 0x10ffffL);
				break;
			} else {
				goto fail_escape;
			}
			digits = -1;  /* Indicate we have at least one digit. */
#else  /* DUK_USE_ES6_UNICODE_ESCAPE */
			DUK_ASSERT(0);  /* Never happens if \u{H+} support disabled. */
#endif  /* DUK_USE_ES6_UNICODE_ESCAPE */
		}
	}

	return escval;

 fail_escape:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_ESCAPE);
	DUK_WO_NORETURN(return 0;);
}

/* Parse legacy octal escape of the form \N{1,3}, e.g. \0, \5, \0377.  Maximum
 * allowed value is \0377 (U+00FF), longest match is used.  Used for both string
 * RegExp octal escape parsing.  Window[0] must be the slash '\' and the first
 * digit must already be validated to be in [0-9] by the caller.
 */
DUK_LOCAL duk_codepoint_t duk__lexer_parse_legacy_octal(duk_lexer_ctx *lex_ctx, duk_small_uint_t *out_adv, duk_bool_t reject_annex_b) {
	duk_codepoint_t cp;
	duk_small_uint_t lookup_idx;
	duk_small_uint_t adv;
	duk_codepoint_t tmp;

	DUK_ASSERT(out_adv != NULL);
	DUK_ASSERT(DUK__LOOKUP(lex_ctx, 0) == DUK_ASC_BACKSLASH);
	DUK_ASSERT(DUK__LOOKUP(lex_ctx, 1) >= DUK_ASC_0 && DUK__LOOKUP(lex_ctx, 1) <= DUK_ASC_9);

	cp = 0;
	tmp = 0;
	for (lookup_idx = 1; lookup_idx <= 3; lookup_idx++) {
		DUK_DDD(DUK_DDDPRINT("lookup_idx=%ld, cp=%ld", (long) lookup_idx, (long) cp));
		tmp = DUK__LOOKUP(lex_ctx, lookup_idx);
		if (tmp < DUK_ASC_0 || tmp > DUK_ASC_7) {
			/* No more valid digits. */
			break;
		}
		tmp = (cp << 3) + (tmp - DUK_ASC_0);
		if (tmp > 0xff) {
			/* Three digit octal escapes above \377 (= 0xff)
			 * are not allowed.
			 */
			break;
		}
		cp = tmp;
	}
	DUK_DDD(DUK_DDDPRINT("final lookup_idx=%ld, cp=%ld", (long) lookup_idx, (long) cp));

	adv = lookup_idx;
	if (lookup_idx == 1) {
		DUK_DDD(DUK_DDDPRINT("\\8 or \\9 -> treat as literal, accept in strict mode too"));
		DUK_ASSERT(tmp == DUK_ASC_8 || tmp == DUK_ASC_9);
		cp = tmp;
		adv++;  /* correction to above, eat offending character */
	} else if (lookup_idx == 2 && cp == 0) {
		/* Note: 'foo\0bar' is OK in strict mode, but 'foo\00bar' is not.
		 * It won't be interpreted as 'foo\u{0}0bar' but as a SyntaxError.
		 */
		DUK_DDD(DUK_DDDPRINT("\\0 -> accept in strict mode too"));
	} else {
		/* This clause also handles non-shortest zero, e.g. \00. */
		if (reject_annex_b) {
			DUK_DDD(DUK_DDDPRINT("non-zero octal literal %ld -> reject in strict-mode", (long) cp));
			cp = -1;
		} else {
			DUK_DDD(DUK_DDDPRINT("non-zero octal literal %ld -> accepted", (long) cp));
			DUK_ASSERT(cp >= 0 && cp <= 0xff);
		}
	}

	*out_adv = adv;

	DUK_ASSERT((cp >= 0 && cp <= 0xff) || (cp == -1 && reject_annex_b));
	return cp;
}

/* XXX: move strict mode to lex_ctx? */
DUK_LOCAL void duk__lexer_parse_string_literal(duk_lexer_ctx *lex_ctx, duk_token *out_token, duk_small_int_t quote, duk_bool_t strict_mode) {
	duk_small_uint_t adv;

	for (adv = 1 /* initial quote */ ;;) {
		duk_codepoint_t x;

		DUK__ADVANCECHARS(lex_ctx, adv);  /* eat opening quote on first loop */
		x = DUK__L0();

		adv = 1;
		if (x == quote) {
			DUK__ADVANCECHARS(lex_ctx, 1);  /* eat closing quote */
			break;
		} else if (x == '\\') {
			/* DUK__L0        -> '\' char
			 * DUK__L1 ... DUK__L5 -> more lookup
			 */
			duk_small_int_t emitcp = -1;

			x = DUK__L1();

			/* How much to advance before next loop. */
			adv = 2;  /* note: long live range */

			switch (x) {
			case '\'':
				emitcp = 0x0027;
				break;
			case '"':
				emitcp = 0x0022;
				break;
			case '\\':
				emitcp = 0x005c;
				break;
			case 'b':
				emitcp = 0x0008;
				break;
			case 'f':
				emitcp = 0x000c;
				break;
			case 'n':
				emitcp = 0x000a;
				break;
			case 'r':
				emitcp = 0x000d;
				break;
			case 't':
				emitcp = 0x0009;
				break;
			case 'v':
				emitcp = 0x000b;
				break;
			case 'x':
			case 'u': {
				duk_codepoint_t esc_cp;
				esc_cp = duk__lexer_parse_escape(lex_ctx, 1 /*allow_es6*/);
				DUK__APPENDBUFFER(lex_ctx, esc_cp);
				adv = 0;
				break;
			}
			default: {
				if (duk_unicode_is_line_terminator(x)) {
					/* line continuation */
					if (x == 0x000d && DUK__L2() == 0x000a) {
						/* CR LF again a special case */
						adv = 3;  /* line terminator, CR, LF */
					}
				} else if (DUK__ISDIGIT(x)) {
					/*
					 *  Octal escape or zero escape:
					 *    \0                                     (lookahead not OctalDigit)
					 *    \1 ... \7                              (lookahead not OctalDigit)
					 *    \ZeroToThree OctalDigit                (lookahead not OctalDigit)
					 *    \FourToSeven OctalDigit                (no lookahead restrictions)
					 *    \ZeroToThree OctalDigit OctalDigit     (no lookahead restrictions)
					 *
					 *  Zero escape is part of the standard syntax.  Octal escapes are
					 *  defined in E5 Section B.1.2, and are only allowed in non-strict mode.
					 *  Any other productions starting with a decimal digit are invalid
					 *  but are in practice treated like identity escapes.
					 *
					 *  Parse octal (up to 3 digits) from the lookup window.
					 */

					emitcp = duk__lexer_parse_legacy_octal(lex_ctx, &adv, strict_mode /*reject_annex_b*/);
					if (emitcp < 0) {
						goto fail_escape;
					}
				} else if (x < 0) {
					goto fail_unterminated;
				} else {
					/* escaped NonEscapeCharacter */
					DUK__APPENDBUFFER(lex_ctx, x);
				}
			}  /* end default clause */
			}  /* end switch */

			/* Shared handling for single codepoint escapes. */
			if (emitcp >= 0) {
				DUK__APPENDBUFFER(lex_ctx, emitcp);
			}

			/* Track number of escapes; count not really needed but directive
			 * prologues need to detect whether there were any escapes or line
			 * continuations or not.
			 */
			out_token->num_escapes++;
		} else if (x >= 0x20 && x <= 0x7f) {
			/* Fast path for ASCII case, avoids line terminator
			 * check and CESU-8 encoding.
			 */
			DUK_ASSERT(x >= 0);
			DUK_ASSERT(!duk_unicode_is_line_terminator(x));
			DUK_ASSERT(x != quote);
			DUK_ASSERT(x != DUK_ASC_BACKSLASH);
			DUK__APPENDBUFFER_ASCII(lex_ctx, x);
		} else if (x < 0 || duk_unicode_is_line_terminator(x)) {
			goto fail_unterminated;
		} else {
			/* Character which is part of the string but wasn't handled
			 * by the fast path.
			 */
			DUK__APPENDBUFFER(lex_ctx, x);
		}
	} /* string parse loop */

	return;

 fail_escape:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_ESCAPE);
	DUK_WO_NORETURN(return;);

 fail_unterminated:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_UNTERMINATED_STRING);
	DUK_WO_NORETURN(return;);
}

/* Skip to end-of-line (or end-of-file), used for single line comments. */
DUK_LOCAL void duk__lexer_skip_to_endofline(duk_lexer_ctx *lex_ctx) {
	for (;;) {
		duk_codepoint_t x;

		x = DUK__L0();
		if (x < 0 || duk_unicode_is_line_terminator(x)) {
			break;
		}
		DUK__ADVANCECHARS(lex_ctx, 1);
	}
}

/*
 *  Parse ECMAScript source InputElementDiv or InputElementRegExp
 *  (E5 Section 7), skipping whitespace, comments, and line terminators.
 *
 *  Possible results are:
 *    (1) a token
 *    (2) a line terminator (skipped)
 *    (3) a comment (skipped)
 *    (4) EOF
 *
 *  White space is automatically skipped from the current position (but
 *  not after the input element).  If input has already ended, returns
 *  DUK_TOK_EOF indefinitely.  If a parse error occurs, uses an DUK_ERROR()
 *  macro call (and hence a longjmp through current heap longjmp context).
 *  Comments and line terminator tokens are automatically skipped.
 *
 *  The input element being matched is determined by regexp_mode; if set,
 *  parses a InputElementRegExp, otherwise a InputElementDiv.  The
 *  difference between these are handling of productions starting with a
 *  forward slash.
 *
 *  If strict_mode is set, recognizes additional future reserved words
 *  specific to strict mode, and refuses to parse octal literals.
 *
 *  The matching strategy below is to (currently) use a six character
 *  lookup window to quickly determine which production is the -longest-
 *  matching one, and then parse that.  The top-level if-else clauses
 *  match the first character, and the code blocks for each clause
 *  handle -all- alternatives for that first character.  ECMAScript
 *  specification uses the "longest match wins" semantics, so the order
 *  of the if-clauses matters.
 *
 *  Misc notes:
 *
 *    * ECMAScript numeric literals do not accept a sign character.
 *      Consequently e.g. "-1.0" is parsed as two tokens: a negative
 *      sign and a positive numeric literal.  The compiler performs
 *      the negation during compilation, so this has no adverse impact.
 *
 *    * There is no token for "undefined": it is just a value available
 *      from the global object (or simply established by doing a reference
 *      to an undefined value).
 *
 *    * Some contexts want Identifier tokens, which are IdentifierNames
 *      excluding reserved words, while some contexts want IdentifierNames
 *      directly.  In the latter case e.g. "while" is interpreted as an
 *      identifier name, not a DUK_TOK_WHILE token.  The solution here is
 *      to provide both token types: DUK_TOK_WHILE goes to 't' while
 *      DUK_TOK_IDENTIFIER goes to 't_nores', and 'slot1' always contains
 *      the identifier / keyword name.
 *
 *    * Directive prologue needs to identify string literals such as
 *      "use strict" and 'use strict', which are sensitive to line
 *      continuations and escape sequences.  For instance, "use\u0020strict"
 *      is a valid directive but is distinct from "use strict".  The solution
 *      here is to decode escapes while tokenizing, but to keep track of the
 *      number of escapes.  Directive detection can then check that the
 *      number of escapes is zero.
 *
 *    * Multi-line comments with one or more internal LineTerminator are
 *      treated like a line terminator to comply with automatic semicolon
 *      insertion.
 */

DUK_INTERNAL
void duk_lexer_parse_js_input_element(duk_lexer_ctx *lex_ctx,
                                      duk_token *out_token,
                                      duk_bool_t strict_mode,
                                      duk_bool_t regexp_mode) {
	duk_codepoint_t x;           /* temporary, must be signed and 32-bit to hold Unicode code points */
	duk_small_uint_t advtok = 0; /* (advance << 8) + token_type, updated at function end,
	                              * init is unnecessary but suppresses "may be used uninitialized" warnings.
	                              */
	duk_bool_t got_lineterm = 0;  /* got lineterm preceding non-whitespace, non-lineterm token */

	if (++lex_ctx->token_count >= lex_ctx->token_limit) {
		goto fail_token_limit;
	}

	out_token->t = DUK_TOK_EOF;
	out_token->t_nores = DUK_TOK_INVALID;  /* marker: copy t if not changed */
#if 0  /* not necessary to init, disabled for faster parsing */
	out_token->num = DUK_DOUBLE_NAN;
	out_token->str1 = NULL;
	out_token->str2 = NULL;
#endif
	out_token->num_escapes = 0;
	/* out_token->lineterm set by caller */

	/* This would be nice, but parsing is faster without resetting the
	 * value slots.  The only side effect is that references to temporary
	 * string values may linger until lexing is finished; they're then
	 * freed normally.
	 */
#if 0
	duk_to_undefined(lex_ctx->thr, lex_ctx->slot1_idx);
	duk_to_undefined(lex_ctx->thr, lex_ctx->slot2_idx);
#endif

	/* 'advtok' indicates how much to advance and which token id to assign
	 * at the end.  This shared functionality minimizes code size.  All
	 * code paths are required to set 'advtok' to some value, so no default
	 * init value is used.  Code paths calling DUK_ERROR() never return so
	 * they don't need to set advtok.
	 */

	/*
	 *  Matching order:
	 *
	 *    Punctuator first chars, also covers comments, regexps
	 *    LineTerminator
	 *    Identifier or reserved word, also covers null/true/false literals
	 *    NumericLiteral
	 *    StringLiteral
	 *    EOF
	 *
	 *  The order does not matter as long as the longest match is
	 *  always correctly identified.  There are order dependencies
	 *  in the clauses, so it's not trivial to convert to a switch.
	 */

 restart_lineupdate:
	out_token->start_line = lex_ctx->window[0].line;

 restart:
	out_token->start_offset = lex_ctx->window[0].offset;

	x = DUK__L0();

	switch (x) {
	case DUK_ASC_SPACE:
	case DUK_ASC_HT:  /* fast paths for space and tab */
		DUK__ADVANCECHARS(lex_ctx, 1);
		goto restart;
	case DUK_ASC_LF:  /* LF line terminator; CR LF and Unicode lineterms are handled in slow path */
		DUK__ADVANCECHARS(lex_ctx, 1);
		got_lineterm = 1;
		goto restart_lineupdate;
#if defined(DUK_USE_SHEBANG_COMMENTS)
	case DUK_ASC_HASH:  /* '#' */
		if (DUK__L1() == DUK_ASC_EXCLAMATION && lex_ctx->window[0].offset == 0 &&
		    (lex_ctx->flags & DUK_COMPILE_SHEBANG)) {
			/* "Shebang" comment ('#! ...') on first line. */
			/* DUK__ADVANCECHARS(lex_ctx, 2) would be correct here, but not necessary */
			duk__lexer_skip_to_endofline(lex_ctx);
			goto restart;  /* line terminator will be handled on next round */
		}
		goto fail_token;
#endif  /* DUK_USE_SHEBANG_COMMENTS */
	case DUK_ASC_SLASH:  /* '/' */
		if (DUK__L1() == DUK_ASC_SLASH) {
			/*
			 *  E5 Section 7.4, allow SourceCharacter (which is any 16-bit
			 *  code point).
			 */

			/* DUK__ADVANCECHARS(lex_ctx, 2) would be correct here, but not necessary */
			duk__lexer_skip_to_endofline(lex_ctx);
			goto restart;  /* line terminator will be handled on next round */
		} else if (DUK__L1() == DUK_ASC_STAR) {
			/*
			 *  E5 Section 7.4.  If the multi-line comment contains a newline,
			 *  it is treated like a single line terminator for automatic
			 *  semicolon insertion.
			 */

			duk_bool_t last_asterisk = 0;
			DUK__ADVANCECHARS(lex_ctx, 2);
			for (;;) {
				x = DUK__L0();
				if (x < 0) {
					goto fail_unterm_comment;
				}
				DUK__ADVANCECHARS(lex_ctx, 1);
				if (last_asterisk && x == DUK_ASC_SLASH) {
					break;
				}
				if (duk_unicode_is_line_terminator(x)) {
					got_lineterm = 1;
				}
				last_asterisk = (x == DUK_ASC_STAR);
			}
			goto restart_lineupdate;
		} else if (regexp_mode) {
#if defined(DUK_USE_REGEXP_SUPPORT)
			/*
			 *  "/" followed by something in regexp mode.  See E5 Section 7.8.5.
			 *
			 *  RegExp parsing is a bit complex.  First, the regexp body is delimited
			 *  by forward slashes, but the body may also contain forward slashes as
			 *  part of an escape sequence or inside a character class (delimited by
			 *  square brackets).  A mini state machine is used to implement these.
			 *
			 *  Further, an early (parse time) error must be thrown if the regexp
			 *  would cause a run-time error when used in the expression new RegExp(...).
			 *  Parsing here simply extracts the (candidate) regexp, and also accepts
			 *  invalid regular expressions (which are delimited properly).  The caller
			 *  (compiler) must perform final validation and regexp compilation.
			 *
			 *  RegExp first char may not be '/' (single line comment) or '*' (multi-
			 *  line comment).  These have already been checked above, so there is no
			 *  need below for special handling of the first regexp character as in
			 *  the E5 productions.
			 *
			 *  About unicode escapes within regexp literals:
			 *
			 *      E5 Section 7.8.5 grammar does NOT accept \uHHHH escapes.
			 *      However, Section 6 states that regexps accept the escapes,
			 *      see paragraph starting with "In string literals...".
			 *      The regexp grammar, which sees the decoded regexp literal
			 *      (after lexical parsing) DOES have a \uHHHH unicode escape.
			 *      So, for instance:
			 *
			 *          /\u1234/
			 *
			 *      should first be parsed by the lexical grammar as:
			 *
			 *          '\' 'u'      RegularExpressionBackslashSequence
			 *          '1'          RegularExpressionNonTerminator
			 *          '2'          RegularExpressionNonTerminator
			 *          '3'          RegularExpressionNonTerminator
			 *          '4'          RegularExpressionNonTerminator
			 *
			 *      and the escape itself is then parsed by the regexp engine.
			 *      This is the current implementation.
			 *
			 *  Minor spec inconsistency:
			 *
			 *      E5 Section 7.8.5 RegularExpressionBackslashSequence is:
			 *
			 *         \ RegularExpressionNonTerminator
			 *
			 *      while Section A.1 RegularExpressionBackslashSequence is:
			 *
			 *         \ NonTerminator
			 *
			 *      The latter is not normative and a typo.
			 *
			 */

			/* first, parse regexp body roughly */

			duk_small_int_t state = 0;  /* 0=base, 1=esc, 2=class, 3=class+esc */

			DUK__INITBUFFER(lex_ctx);
			for (;;) {
				DUK__ADVANCECHARS(lex_ctx, 1);  /* skip opening slash on first loop */
				x = DUK__L0();
				if (x < 0 || duk_unicode_is_line_terminator(x)) {
					goto fail_unterm_regexp;
				}
				x = DUK__L0();  /* re-read to avoid spill / fetch */
				if (state == 0) {
					if (x == DUK_ASC_SLASH) {
						DUK__ADVANCECHARS(lex_ctx, 1);  /* eat closing slash */
						break;
					} else if (x == DUK_ASC_BACKSLASH) {
						state = 1;
					} else if (x == DUK_ASC_LBRACKET) {
						state = 2;
					}
				} else if (state == 1) {
					state = 0;
				} else if (state == 2) {
					if (x == DUK_ASC_RBRACKET) {
						state = 0;
					} else if (x == DUK_ASC_BACKSLASH) {
						state = 3;
					}
				} else { /* state == 3 */
					state = 2;
				}
				DUK__APPENDBUFFER(lex_ctx, x);
			}
			out_token->str1 = duk__internbuffer(lex_ctx, lex_ctx->slot1_idx);

			/* second, parse flags */

			DUK__INITBUFFER(lex_ctx);
			for (;;) {
				x = DUK__L0();
				if (!duk_unicode_is_identifier_part(x)) {
					break;
				}
				x = DUK__L0();  /* re-read to avoid spill / fetch */
				DUK__APPENDBUFFER(lex_ctx, x);
				DUK__ADVANCECHARS(lex_ctx, 1);
			}
			out_token->str2 = duk__internbuffer(lex_ctx, lex_ctx->slot2_idx);

			DUK__INITBUFFER(lex_ctx);  /* free some memory */

			/* validation of the regexp is caller's responsibility */

			advtok = DUK__ADVTOK(0, DUK_TOK_REGEXP);
#else  /* DUK_USE_REGEXP_SUPPORT */
			goto fail_regexp_support;
#endif  /* DUK_USE_REGEXP_SUPPORT */
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			/* "/=" and not in regexp mode */
			advtok = DUK__ADVTOK(2, DUK_TOK_DIV_EQ);
		} else {
			/* "/" and not in regexp mode */
			advtok = DUK__ADVTOK(1, DUK_TOK_DIV);
		}
		break;
	case DUK_ASC_LCURLY:  /* '{' */
		advtok = DUK__ADVTOK(1, DUK_TOK_LCURLY);
		break;
	case DUK_ASC_RCURLY:  /* '}' */
		advtok = DUK__ADVTOK(1, DUK_TOK_RCURLY);
		break;
	case DUK_ASC_LPAREN:  /* '(' */
		advtok = DUK__ADVTOK(1, DUK_TOK_LPAREN);
		break;
	case DUK_ASC_RPAREN:  /* ')' */
		advtok = DUK__ADVTOK(1, DUK_TOK_RPAREN);
		break;
	case DUK_ASC_LBRACKET:  /* '[' */
		advtok = DUK__ADVTOK(1, DUK_TOK_LBRACKET);
		break;
	case DUK_ASC_RBRACKET:  /* ']' */
		advtok = DUK__ADVTOK(1, DUK_TOK_RBRACKET);
		break;
	case DUK_ASC_PERIOD:  /* '.' */
		if (DUK__ISDIGIT(DUK__L1())) {
			/* Period followed by a digit can only start DecimalLiteral
			 * (handled in slow path).  We could jump straight into the
			 * DecimalLiteral handling but should avoid goto to inside
			 * a block.
			 */
			goto slow_path;
		}
		advtok = DUK__ADVTOK(1, DUK_TOK_PERIOD);
		break;
	case DUK_ASC_SEMICOLON:  /* ';' */
		advtok = DUK__ADVTOK(1, DUK_TOK_SEMICOLON);
		break;
	case DUK_ASC_COMMA:  /* ',' */
		advtok = DUK__ADVTOK(1, DUK_TOK_COMMA);
		break;
	case DUK_ASC_LANGLE:  /* '<' */
#if defined(DUK_USE_HTML_COMMENTS)
		if (DUK__L1() == DUK_ASC_EXCLAMATION && DUK__L2() == DUK_ASC_MINUS && DUK__L3() == DUK_ASC_MINUS) {
			/*
			 *  ES2015: B.1.3, handle "<!--" SingleLineHTMLOpenComment
			 */

			/* DUK__ADVANCECHARS(lex_ctx, 4) would be correct here, but not necessary */
			duk__lexer_skip_to_endofline(lex_ctx);
			goto restart;  /* line terminator will be handled on next round */
		}
		else
#endif  /* DUK_USE_HTML_COMMENTS */
		if (DUK__L1() == DUK_ASC_LANGLE && DUK__L2() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(3, DUK_TOK_ALSHIFT_EQ);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_LE);
		} else if (DUK__L1() == DUK_ASC_LANGLE) {
			advtok = DUK__ADVTOK(2, DUK_TOK_ALSHIFT);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_LT);
		}
		break;
	case DUK_ASC_RANGLE:  /* '>' */
		if (DUK__L1() == DUK_ASC_RANGLE && DUK__L2() == DUK_ASC_RANGLE && DUK__L3() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(4, DUK_TOK_RSHIFT_EQ);
		} else if (DUK__L1() == DUK_ASC_RANGLE && DUK__L2() == DUK_ASC_RANGLE) {
			advtok = DUK__ADVTOK(3, DUK_TOK_RSHIFT);
		} else if (DUK__L1() == DUK_ASC_RANGLE && DUK__L2() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(3, DUK_TOK_ARSHIFT_EQ);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_GE);
		} else if (DUK__L1() == DUK_ASC_RANGLE) {
			advtok = DUK__ADVTOK(2, DUK_TOK_ARSHIFT);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_GT);
		}
		break;
	case DUK_ASC_EQUALS:  /* '=' */
		if (DUK__L1() == DUK_ASC_EQUALS && DUK__L2() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(3, DUK_TOK_SEQ);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_EQUALSIGN);
		}
		break;
	case DUK_ASC_EXCLAMATION:  /* '!' */
		if (DUK__L1() == DUK_ASC_EQUALS && DUK__L2() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(3, DUK_TOK_SNEQ);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_NEQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_LNOT);
		}
		break;
	case DUK_ASC_PLUS:  /* '+' */
		if (DUK__L1() == DUK_ASC_PLUS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_INCREMENT);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_ADD_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_ADD);
		}
		break;
	case DUK_ASC_MINUS:  /* '-' */
#if defined(DUK_USE_HTML_COMMENTS)
		if (got_lineterm && DUK__L1() == DUK_ASC_MINUS && DUK__L2() == DUK_ASC_RANGLE) {
			/*
			 *  ES2015: B.1.3, handle "-->" SingleLineHTMLCloseComment
			 *  Only allowed:
			 *  - on new line
			 *  - preceded only by whitespace
			 *  - preceded by end of multiline comment and optional whitespace
			 *
			 * Since whitespace generates no tokens, and multiline comments
			 * are treated as a line ending, consulting `got_lineterm` is
			 * sufficient to test for these three options.
			 */

			/* DUK__ADVANCECHARS(lex_ctx, 3) would be correct here, but not necessary */
			duk__lexer_skip_to_endofline(lex_ctx);
			goto restart;  /* line terminator will be handled on next round */
		} else
#endif  /* DUK_USE_HTML_COMMENTS */
		if (DUK__L1() == DUK_ASC_MINUS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_DECREMENT);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_SUB_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_SUB);
		}
		break;
	case DUK_ASC_STAR:  /* '*' */
#if defined(DUK_USE_ES7_EXP_OPERATOR)
		if (DUK__L1() == DUK_ASC_STAR && DUK__L2() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(3, DUK_TOK_EXP_EQ);
		} else if (DUK__L1() == DUK_ASC_STAR) {
			advtok = DUK__ADVTOK(2, DUK_TOK_EXP);
		} else
#endif
		if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_MUL_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_MUL);
		}
		break;
	case DUK_ASC_PERCENT:  /* '%' */
		if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_MOD_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_MOD);
		}
		break;
	case DUK_ASC_AMP:  /* '&' */
		if (DUK__L1() == DUK_ASC_AMP) {
			advtok = DUK__ADVTOK(2, DUK_TOK_LAND);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_BAND_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_BAND);
		}
		break;
	case DUK_ASC_PIPE:  /* '|' */
		if (DUK__L1() == DUK_ASC_PIPE) {
			advtok = DUK__ADVTOK(2, DUK_TOK_LOR);
		} else if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_BOR_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_BOR);
		}
		break;
	case DUK_ASC_CARET:  /* '^' */
		if (DUK__L1() == DUK_ASC_EQUALS) {
			advtok = DUK__ADVTOK(2, DUK_TOK_BXOR_EQ);
		} else {
			advtok = DUK__ADVTOK(1, DUK_TOK_BXOR);
		}
		break;
	case DUK_ASC_TILDE:  /* '~' */
		advtok = DUK__ADVTOK(1, DUK_TOK_BNOT);
		break;
	case DUK_ASC_QUESTION:  /* '?' */
		advtok = DUK__ADVTOK(1, DUK_TOK_QUESTION);
		break;
	case DUK_ASC_COLON:  /* ':' */
		advtok = DUK__ADVTOK(1, DUK_TOK_COLON);
		break;
	case DUK_ASC_DOUBLEQUOTE:    /* '"' */
	case DUK_ASC_SINGLEQUOTE: {  /* '\'' */
		DUK__INITBUFFER(lex_ctx);
		duk__lexer_parse_string_literal(lex_ctx, out_token, x /*quote*/, strict_mode);
		duk__internbuffer(lex_ctx, lex_ctx->slot1_idx);
		out_token->str1 = duk_known_hstring(lex_ctx->thr, lex_ctx->slot1_idx);

		DUK__INITBUFFER(lex_ctx);  /* free some memory */

		advtok = DUK__ADVTOK(0, DUK_TOK_STRING);
		break;
	}
	default:
		goto slow_path;
	}  /* switch */

	goto skip_slow_path;

 slow_path:
	if (duk_unicode_is_line_terminator(x)) {
		if (x == 0x000d && DUK__L1() == 0x000a) {
			/*
			 *  E5 Section 7.3: CR LF is detected as a single line terminator for
			 *  line numbers.  Here we also detect it as a single line terminator
			 *  token.
			 */
			DUK__ADVANCECHARS(lex_ctx, 2);
		} else {
			DUK__ADVANCECHARS(lex_ctx, 1);
		}
		got_lineterm = 1;
		goto restart_lineupdate;
	} else if (duk_unicode_is_identifier_start(x) || x == DUK_ASC_BACKSLASH) {
		/*
		 *  Parse an identifier and then check whether it is:
		 *    - reserved word (keyword or other reserved word)
		 *    - "null"  (NullLiteral)
		 *    - "true"  (BooleanLiteral)
		 *    - "false" (BooleanLiteral)
		 *    - anything else => identifier
		 *
		 *  This does not follow the E5 productions cleanly, but is
		 *  useful and compact.
		 *
		 *  Note that identifiers may contain Unicode escapes,
		 *  see E5 Sections 6 and 7.6.  They must be decoded first,
		 *  and the result checked against allowed characters.
		 *  The above if-clause accepts an identifier start and an
		 *  '\' character -- no other token can begin with a '\'.
		 *
		 *  Note that "get" and "set" are not reserved words in E5
		 *  specification so they are recognized as plain identifiers
		 *  (the tokens DUK_TOK_GET and DUK_TOK_SET are actually not
		 *  used now).  The compiler needs to work around this.
		 *
		 *  Strictly speaking, following ECMAScript longest match
		 *  specification, an invalid escape for the first character
		 *  should cause a syntax error.  However, an invalid escape
		 *  for IdentifierParts should just terminate the identifier
		 *  early (longest match), and let the next tokenization
		 *  fail.  For instance Rhino croaks with 'foo\z' when
		 *  parsing the identifier.  This has little practical impact.
		 */

		duk_small_uint_t i, i_end;
		duk_bool_t first = 1;
		duk_hstring *str;

		DUK__INITBUFFER(lex_ctx);
		for (;;) {
			/* re-lookup first char on first loop */
			if (DUK__L0() == DUK_ASC_BACKSLASH) {
				duk_codepoint_t esc_cp;
				if (DUK__L1() != DUK_ASC_LC_U) {
					goto fail_escape;
				}
				esc_cp = duk__lexer_parse_escape(lex_ctx, 1 /*allow_es6*/);
				DUK__APPENDBUFFER(lex_ctx, esc_cp);

				/* IdentifierStart is stricter than IdentifierPart, so if the first
				 * character is escaped, must have a stricter check here.
				 */
				if (!(first ? duk_unicode_is_identifier_start(esc_cp) : duk_unicode_is_identifier_part(esc_cp))) {
					goto fail_escape;
				}

				/* Track number of escapes: necessary for proper keyword
				 * detection.
				 */
				out_token->num_escapes++;
			} else {
				/* Note: first character is checked against this.  But because
				 * IdentifierPart includes all IdentifierStart characters, and
				 * the first character (if unescaped) has already been checked
				 * in the if condition, this is OK.
				 */
				if (!duk_unicode_is_identifier_part(DUK__L0())) {
					break;
				}
				DUK__APPENDBUFFER(lex_ctx, DUK__L0());
				DUK__ADVANCECHARS(lex_ctx, 1);
			}
			first = 0;
		}

		out_token->str1 = duk__internbuffer(lex_ctx, lex_ctx->slot1_idx);
		str = out_token->str1;
		out_token->t_nores = DUK_TOK_IDENTIFIER;

		DUK__INITBUFFER(lex_ctx);  /* free some memory */

		/*
		 *  Interned identifier is compared against reserved words, which are
		 *  currently interned into the heap context.  See genbuiltins.py.
		 *
		 *  Note that an escape in the identifier disables recognition of
		 *  keywords; e.g. "\u0069f = 1;" is a valid statement (assigns to
		 *  identifier named "if").  This is not necessarily compliant,
		 *  see test-dec-escaped-char-in-keyword.js.
		 *
		 *  Note: "get" and "set" are awkward.  They are not officially
		 *  ReservedWords (and indeed e.g. "var set = 1;" is valid), and
		 *  must come out as DUK_TOK_IDENTIFIER.  The compiler needs to
		 *  work around this a bit.
		 */

		/* XXX: optimize by adding the token numbers directly into the
		 * always interned duk_hstring objects (there should be enough
		 * flag bits free for that)?
		 */

		i_end = (strict_mode ? DUK_STRIDX_END_RESERVED : DUK_STRIDX_START_STRICT_RESERVED);

		advtok = DUK__ADVTOK(0, DUK_TOK_IDENTIFIER);
		if (out_token->num_escapes == 0) {
			for (i = DUK_STRIDX_START_RESERVED; i < i_end; i++) {
				DUK_ASSERT_DISABLE(i >= 0);  /* unsigned */
				DUK_ASSERT(i < DUK_HEAP_NUM_STRINGS);
				if (DUK_HTHREAD_GET_STRING(lex_ctx->thr, i) == str) {
					advtok = DUK__ADVTOK(0, DUK_STRIDX_TO_TOK(i));
					break;
				}
			}
		}
	} else if (DUK__ISDIGIT(x) || (x == DUK_ASC_PERIOD)) {
		/* Note: decimal number may start with a period, but must be followed by a digit */

		/*
		 *  Pre-parsing for decimal, hex, octal (both legacy and ES2015),
		 *  and binary literals, followed by an actual parser step
		 *  provided by numconv.
		 *
		 *  Note: the leading sign character ('+' or '-') is -not- part of
		 *  the production in E5 grammar, and that the a DecimalLiteral
		 *  starting with a '0' must be followed by a non-digit.
		 *
		 *  XXX: the two step parsing process is quite awkward, it would
		 *  be more straightforward to allow numconv to parse the longest
		 *  valid prefix (it already does that, it only needs to indicate
		 *  where the input ended).  However, the lexer decodes characters
		 *  using a limited lookup window, so this is not a trivial change.
		 */

		/* XXX: because of the final check below (that the literal is not
		 * followed by a digit), this could maybe be simplified, if we bail
		 * out early from a leading zero (and if there are no periods etc).
		 * Maybe too complex.
		 */

		duk_double_t val;
		duk_bool_t legacy_oct = 0;
		duk_small_int_t state;  /* 0=before period/exp,
		                         * 1=after period, before exp
		                         * 2=after exp, allow '+' or '-'
		                         * 3=after exp and exp sign
		                         */
		duk_small_uint_t s2n_flags;
		duk_codepoint_t y, z;
		duk_small_int_t s2n_radix = 10;
		duk_small_uint_t pre_adv = 0;

		DUK__INITBUFFER(lex_ctx);
		y = DUK__L1();

		if (x == DUK_ASC_0) {
			z = DUK_LOWERCASE_CHAR_ASCII(y);

			pre_adv = 2;  /* default for 0xNNN, 0oNNN, 0bNNN. */
			if (z == DUK_ASC_LC_X) {
				s2n_radix = 16;
			} else if (z == DUK_ASC_LC_O) {
				s2n_radix = 8;
			} else if (z == DUK_ASC_LC_B) {
				s2n_radix = 2;
			} else {
				pre_adv = 0;
				if (DUK__ISDIGIT(y)) {
					if (strict_mode) {
						/* Reject octal like \07 but also octal-lookalike
						 * decimal like \08 in strict mode.
						 */
						goto fail_number_literal;
					} else {
						/* Legacy OctalIntegerLiteral or octal-lookalice
						 * decimal.  Deciding between the two happens below
						 * in digit scanning.
						 */
						DUK__APPENDBUFFER(lex_ctx, x);
						pre_adv = 1;
						legacy_oct = 1;
						s2n_radix = 8;  /* tentative unless conflicting digits found */
					}
				}
			}
		}

		DUK__ADVANCECHARS(lex_ctx, pre_adv);

		/* XXX: we could parse integers here directly, and fall back
		 * to numconv only when encountering a fractional expression
		 * or when an octal literal turned out to be decimal (0778 etc).
		 */
		state = 0;
		for (;;) {
			x = DUK__L0();  /* re-lookup curr char on first round */
			if (DUK__ISDIGIT(x)) {
				/* Note: intentionally allow leading zeroes here, as the
				 * actual parser will check for them.
				 */
				if (state == 0 && legacy_oct && (x == DUK_ASC_8 || x == DUK_ASC_9)) {
					/* Started out as an octal-lookalike
					 * but interpreted as decimal, e.g.
					 * '0779' -> 779.  This also means
					 * that fractions are allowed, e.g.
					 * '0779.123' is allowed but '0777.123'
					 * is not!
					 */
					s2n_radix = 10;
				}
				if (state == 2) {
					state = 3;
				}
			} else if (s2n_radix == 16 && DUK__ISHEXDIGIT(x)) {
				/* Note: 'e' and 'E' are also accepted here. */
				;
			} else if (x == DUK_ASC_PERIOD) {
				if (state >= 1 || s2n_radix != 10) {
					break;
				} else {
					state = 1;
				}
			} else if (x == DUK_ASC_LC_E || x == DUK_ASC_UC_E) {
				if (state >= 2 || s2n_radix != 10) {
					break;
				} else {
					state = 2;
				}
			} else if (x == DUK_ASC_MINUS || x == DUK_ASC_PLUS) {
				if (state != 2) {
					break;
				} else {
					state = 3;
				}
			} else {
				break;
			}
			DUK__APPENDBUFFER(lex_ctx, x);
			DUK__ADVANCECHARS(lex_ctx, 1);
		}

		/* XXX: better coercion */
		(void) duk__internbuffer(lex_ctx, lex_ctx->slot1_idx);

		if (s2n_radix != 10) {
			/* For bases other than 10, integer only. */
			s2n_flags = DUK_S2N_FLAG_ALLOW_LEADING_ZERO;
		} else {
			s2n_flags = DUK_S2N_FLAG_ALLOW_EXP |
			            DUK_S2N_FLAG_ALLOW_FRAC |
			            DUK_S2N_FLAG_ALLOW_NAKED_FRAC |
			            DUK_S2N_FLAG_ALLOW_EMPTY_FRAC |
			            DUK_S2N_FLAG_ALLOW_LEADING_ZERO;
		}

		duk_dup(lex_ctx->thr, lex_ctx->slot1_idx);
		duk_numconv_parse(lex_ctx->thr, s2n_radix, s2n_flags);
		val = duk_to_number_m1(lex_ctx->thr);
		if (DUK_ISNAN(val)) {
			goto fail_number_literal;
		}
		duk_replace(lex_ctx->thr, lex_ctx->slot1_idx);  /* could also just pop? */

		DUK__INITBUFFER(lex_ctx);  /* free some memory */

		/* Section 7.8.3 (note): NumericLiteral must be followed by something other than
		 * IdentifierStart or DecimalDigit.
		 */

		if (DUK__ISDIGIT(DUK__L0()) || duk_unicode_is_identifier_start(DUK__L0())) {
			goto fail_number_literal;
		}

		out_token->num = val;
		advtok = DUK__ADVTOK(0, DUK_TOK_NUMBER);
	} else if (duk_unicode_is_whitespace(DUK__LOOKUP(lex_ctx, 0))) {
		DUK__ADVANCECHARS(lex_ctx, 1);
		goto restart;
	} else if (x < 0) {
		advtok = DUK__ADVTOK(0, DUK_TOK_EOF);
	} else {
		goto fail_token;
	}
 skip_slow_path:

	/*
	 *  Shared exit path
	 */

	DUK__ADVANCEBYTES(lex_ctx, advtok >> 8);
	out_token->t = advtok & 0xff;
	if (out_token->t_nores == DUK_TOK_INVALID) {
		out_token->t_nores = out_token->t;
	}
	out_token->lineterm = got_lineterm;

	/* Automatic semicolon insertion is allowed if a token is preceded
	 * by line terminator(s), or terminates a statement list (right curly
	 * or EOF).
	 */
	if (got_lineterm || out_token->t == DUK_TOK_RCURLY || out_token->t == DUK_TOK_EOF) {
		out_token->allow_auto_semi = 1;
	} else {
		out_token->allow_auto_semi = 0;
	}

	return;

 fail_token_limit:
	DUK_ERROR_RANGE(lex_ctx->thr, DUK_STR_TOKEN_LIMIT);
	DUK_WO_NORETURN(return;);

 fail_token:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_TOKEN);
	DUK_WO_NORETURN(return;);

 fail_number_literal:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_NUMBER_LITERAL);
	DUK_WO_NORETURN(return;);

 fail_escape:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_ESCAPE);
	DUK_WO_NORETURN(return;);

 fail_unterm_regexp:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_UNTERMINATED_REGEXP);
	DUK_WO_NORETURN(return;);

 fail_unterm_comment:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_UNTERMINATED_COMMENT);
	DUK_WO_NORETURN(return;);

#if !defined(DUK_USE_REGEXP_SUPPORT)
 fail_regexp_support:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_REGEXP_SUPPORT_DISABLED);
	DUK_WO_NORETURN(return;);
#endif
}

#if defined(DUK_USE_REGEXP_SUPPORT)

/*
 *  Parse a RegExp token.  The grammar is described in E5 Section 15.10.
 *  Terminal constructions (such as quantifiers) are parsed directly here.
 *
 *  0xffffffffU is used as a marker for "infinity" in quantifiers.  Further,
 *  DUK__MAX_RE_QUANT_DIGITS limits the maximum number of digits that
 *  will be accepted for a quantifier.
 */

DUK_INTERNAL void duk_lexer_parse_re_token(duk_lexer_ctx *lex_ctx, duk_re_token *out_token) {
	duk_small_uint_t advtok = 0;  /* init is unnecessary but suppresses "may be used uninitialized" warnings */
	duk_codepoint_t x, y;

	if (++lex_ctx->token_count >= lex_ctx->token_limit) {
		goto fail_token_limit;
	}

	duk_memzero(out_token, sizeof(*out_token));

	x = DUK__L0();
	y = DUK__L1();

	DUK_DDD(DUK_DDDPRINT("parsing regexp token, L0=%ld, L1=%ld", (long) x, (long) y));

	switch (x) {
	case DUK_ASC_PIPE: {
		advtok = DUK__ADVTOK(1, DUK_RETOK_DISJUNCTION);
		break;
	}
	case DUK_ASC_CARET: {
		advtok = DUK__ADVTOK(1, DUK_RETOK_ASSERT_START);
		break;
	}
	case DUK_ASC_DOLLAR: {
		advtok = DUK__ADVTOK(1, DUK_RETOK_ASSERT_END);
		break;
	}
	case DUK_ASC_QUESTION: {
		out_token->qmin = 0;
		out_token->qmax = 1;
		if (y == DUK_ASC_QUESTION) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 0;
		} else {
			advtok = DUK__ADVTOK(1, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 1;
		}
		break;
	}
	case DUK_ASC_STAR: {
		out_token->qmin = 0;
		out_token->qmax = DUK_RE_QUANTIFIER_INFINITE;
		if (y == DUK_ASC_QUESTION) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 0;
		} else {
			advtok = DUK__ADVTOK(1, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 1;
		}
		break;
	}
	case DUK_ASC_PLUS: {
		out_token->qmin = 1;
		out_token->qmax = DUK_RE_QUANTIFIER_INFINITE;
		if (y == DUK_ASC_QUESTION) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 0;
		} else {
			advtok = DUK__ADVTOK(1, DUK_RETOK_QUANTIFIER);
			out_token->greedy = 1;
		}
		break;
	}
	case DUK_ASC_LCURLY: {
		/* Production allows 'DecimalDigits', including leading zeroes */
		duk_uint32_t val1 = 0;
		duk_uint32_t val2 = DUK_RE_QUANTIFIER_INFINITE;
		duk_small_int_t digits = 0;
#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
		duk_lexer_point lex_pt;
#endif

#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
		/* Store lexer position, restoring if quantifier is invalid. */
		DUK_LEXER_GETPOINT(lex_ctx, &lex_pt);
#endif

		for (;;) {
			DUK__ADVANCECHARS(lex_ctx, 1);  /* eat '{' on entry */
			x = DUK__L0();
			if (DUK__ISDIGIT(x)) {
				digits++;
				val1 = val1 * 10 + (duk_uint32_t) duk__hexval(x);
			} else if (x == DUK_ASC_COMMA) {
				if (digits > DUK__MAX_RE_QUANT_DIGITS) {
					goto invalid_quantifier;
				}
				if (val2 != DUK_RE_QUANTIFIER_INFINITE) {
					goto invalid_quantifier;
				}
				if (DUK__L1() == DUK_ASC_RCURLY) {
					/* form: { DecimalDigits , }, val1 = min count */
					if (digits == 0) {
						goto invalid_quantifier;
					}
					out_token->qmin = val1;
					out_token->qmax = DUK_RE_QUANTIFIER_INFINITE;
					DUK__ADVANCECHARS(lex_ctx, 2);
					break;
				}
				val2 = val1;
				val1 = 0;
				digits = 0;  /* not strictly necessary because of lookahead '}' above */
			} else if (x == DUK_ASC_RCURLY) {
				if (digits > DUK__MAX_RE_QUANT_DIGITS) {
					goto invalid_quantifier;
				}
				if (digits == 0) {
					goto invalid_quantifier;
				}
				if (val2 != DUK_RE_QUANTIFIER_INFINITE) {
					/* val2 = min count, val1 = max count */
					out_token->qmin = val2;
					out_token->qmax = val1;
				} else {
					/* val1 = count */
					out_token->qmin = val1;
					out_token->qmax = val1;
				}
				DUK__ADVANCECHARS(lex_ctx, 1);
				break;
			} else {
				goto invalid_quantifier;
			}
		}
		if (DUK__L0() == DUK_ASC_QUESTION) {
			out_token->greedy = 0;
			DUK__ADVANCECHARS(lex_ctx, 1);
		} else {
			out_token->greedy = 1;
		}
		advtok = DUK__ADVTOK(0, DUK_RETOK_QUANTIFIER);
		break;
 invalid_quantifier:
#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
		/* Failed to match the quantifier, restore lexer and parse
		 * opening brace as a literal.
		 */
		DUK_LEXER_SETPOINT(lex_ctx, &lex_pt);
		advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_CHAR);
		out_token->num = DUK_ASC_LCURLY;
#else
		goto fail_quantifier;
#endif
		break;
	}
	case DUK_ASC_PERIOD: {
		advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_PERIOD);
		break;
	}
	case DUK_ASC_BACKSLASH: {
		/* The E5.1 specification does not seem to allow IdentifierPart characters
		 * to be used as identity escapes.  Unfortunately this includes '$', which
		 * cannot be escaped as '\$'; it needs to be escaped e.g. as '\u0024'.
		 * Many other implementations (including V8 and Rhino, for instance) do
		 * accept '\$' as a valid identity escape, which is quite pragmatic, and
		 * ES2015 Annex B relaxes the rules to allow these (and other) real world forms.
		 */

		advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_CHAR);  /* default: char escape (two chars) */
		if (y == DUK_ASC_LC_B) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ASSERT_WORD_BOUNDARY);
		} else if (y == DUK_ASC_UC_B) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ASSERT_NOT_WORD_BOUNDARY);
		} else if (y == DUK_ASC_LC_F) {
			out_token->num = 0x000c;
		} else if (y == DUK_ASC_LC_N) {
			out_token->num = 0x000a;
		} else if (y == DUK_ASC_LC_T) {
			out_token->num = 0x0009;
		} else if (y == DUK_ASC_LC_R) {
			out_token->num = 0x000d;
		} else if (y == DUK_ASC_LC_V) {
			out_token->num = 0x000b;
		} else if (y == DUK_ASC_LC_C) {
			x = DUK__L2();
			if ((x >= DUK_ASC_LC_A && x <= DUK_ASC_LC_Z) ||
			    (x >= DUK_ASC_UC_A && x <= DUK_ASC_UC_Z)) {
				out_token->num = (duk_uint32_t) (x % 32);
				advtok = DUK__ADVTOK(3, DUK_RETOK_ATOM_CHAR);
			} else {
				goto fail_escape;
			}
		} else if (y == DUK_ASC_LC_X || y == DUK_ASC_LC_U) {
			/* The token value is the Unicode codepoint without
			 * it being decode into surrogate pair characters
			 * here.  The \u{H+} is only allowed in Unicode mode
			 * which we don't support yet.
			 */
			out_token->num = (duk_uint32_t) duk__lexer_parse_escape(lex_ctx, 0 /*allow_es6*/);
			advtok = DUK__ADVTOK(0, DUK_RETOK_ATOM_CHAR);
		} else if (y == DUK_ASC_LC_D) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_DIGIT);
		} else if (y == DUK_ASC_UC_D) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_NOT_DIGIT);
		} else if (y == DUK_ASC_LC_S) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_WHITE);
		} else if (y == DUK_ASC_UC_S) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_NOT_WHITE);
		} else if (y == DUK_ASC_LC_W) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_WORD_CHAR);
		} else if (y == DUK_ASC_UC_W) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_NOT_WORD_CHAR);
		} else if (DUK__ISDIGIT(y)) {
			/* E5 Section 15.10.2.11 */
			if (y == DUK_ASC_0) {
				if (DUK__ISDIGIT(DUK__L2())) {
					goto fail_escape;
				}
				out_token->num = 0x0000;
				advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_CHAR);
			} else {
				/* XXX: shared parsing? */
				duk_uint32_t val = 0;
				duk_small_int_t i;
				for (i = 0; ; i++) {
					if (i >= DUK__MAX_RE_DECESC_DIGITS) {
						goto fail_escape;
					}
					DUK__ADVANCECHARS(lex_ctx, 1);  /* eat backslash on entry */
					x = DUK__L0();
					if (!DUK__ISDIGIT(x)) {
						break;
					}
					val = val * 10 + (duk_uint32_t) duk__hexval(x);
				}
				/* DUK__L0() cannot be a digit, because the loop doesn't terminate if it is */
				advtok = DUK__ADVTOK(0, DUK_RETOK_ATOM_BACKREFERENCE);
				out_token->num = val;
			}
#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
		} else if (y >= 0) {
			/* For ES2015 Annex B, accept any source character as identity
			 * escape except 'c' which is used for control characters.
			 * http://www.ecma-international.org/ecma-262/6.0/#sec-regular-expressions-patterns
			 * Careful not to match end-of-buffer (<0) here.
			 * This is not yet full ES2015 Annex B because cases above
			 * (like hex escape) won't backtrack.
			 */
			DUK_ASSERT(y != DUK_ASC_LC_C);  /* covered above */
#else  /* DUK_USE_ES6_REGEXP_SYNTAX */
		} else if ((y >= 0 && !duk_unicode_is_identifier_part(y)) ||
		           y == DUK_UNICODE_CP_ZWNJ ||
		           y == DUK_UNICODE_CP_ZWJ) {
			/* For ES5.1 identity escapes are not allowed for identifier
			 * parts.  This conflicts with a lot of real world code as this
			 * doesn't e.g. allow escaping a dollar sign as /\$/, see
			 * test-regexp-identity-escape-dollar.js.
			 */
#endif  /* DUK_USE_ES6_REGEXP_SYNTAX */
			out_token->num = (duk_uint32_t) y;
		} else {
			goto fail_escape;
		}
		break;
	}
	case DUK_ASC_LPAREN: {
		/* XXX: naming is inconsistent: ATOM_END_GROUP ends an ASSERT_START_LOOKAHEAD */

		if (y == DUK_ASC_QUESTION) {
			if (DUK__L2() == DUK_ASC_EQUALS) {
				/* (?= */
				advtok = DUK__ADVTOK(3, DUK_RETOK_ASSERT_START_POS_LOOKAHEAD);
			} else if (DUK__L2() == DUK_ASC_EXCLAMATION) {
				/* (?! */
				advtok = DUK__ADVTOK(3, DUK_RETOK_ASSERT_START_NEG_LOOKAHEAD);
			} else if (DUK__L2() == DUK_ASC_COLON) {
				/* (?: */
				advtok = DUK__ADVTOK(3, DUK_RETOK_ATOM_START_NONCAPTURE_GROUP);
			} else {
				goto fail_group;
			}
		} else {
			/* ( */
			advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_START_CAPTURE_GROUP);
		}
		break;
	}
	case DUK_ASC_RPAREN: {
		advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_END_GROUP);
		break;
	}
	case DUK_ASC_LBRACKET: {
		/*
		 *  To avoid creating a heavy intermediate value for the list of ranges,
		 *  only the start token ('[' or '[^') is parsed here.  The regexp
		 *  compiler parses the ranges itself.
		 */

		/* XXX: with DUK_USE_ES6_REGEXP_SYNTAX we should allow left bracket
		 * literal too, but it's not easy to parse without backtracking.
		 */

		advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_START_CHARCLASS);
		if (y == DUK_ASC_CARET) {
			advtok = DUK__ADVTOK(2, DUK_RETOK_ATOM_START_CHARCLASS_INVERTED);
		}
		break;
	}
#if !defined(DUK_USE_ES6_REGEXP_SYNTAX)
	case DUK_ASC_RCURLY:
	case DUK_ASC_RBRACKET: {
		/* Although these could be parsed as PatternCharacters unambiguously (here),
		 * E5 Section 15.10.1 grammar explicitly forbids these as PatternCharacters.
		 */
		goto fail_invalid_char;
		break;
	}
#endif
	case -1: {
		/* EOF */
		advtok = DUK__ADVTOK(0, DUK_TOK_EOF);
		break;
	}
	default: {
		/* PatternCharacter, all excluded characters are matched by cases above */
		advtok = DUK__ADVTOK(1, DUK_RETOK_ATOM_CHAR);
		out_token->num = (duk_uint32_t) x;
		break;
	}
	}

	/*
	 *  Shared exit path
	 */

	DUK__ADVANCEBYTES(lex_ctx, advtok >> 8);
	out_token->t = advtok & 0xff;
	return;

 fail_token_limit:
	DUK_ERROR_RANGE(lex_ctx->thr, DUK_STR_TOKEN_LIMIT);
	DUK_WO_NORETURN(return;);

 fail_escape:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_REGEXP_ESCAPE);
	DUK_WO_NORETURN(return;);

 fail_group:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_REGEXP_GROUP);
	DUK_WO_NORETURN(return;);

#if !defined(DUK_USE_ES6_REGEXP_SYNTAX)
 fail_invalid_char:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_REGEXP_CHARACTER);
	DUK_WO_NORETURN(return;);

 fail_quantifier:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_QUANTIFIER);
	DUK_WO_NORETURN(return;);
#endif
}

/*
 *  Special parser for character classes; calls callback for every
 *  range parsed and returns the number of ranges present.
 */

/* XXX: this duplicates functionality in duk_regexp.c where a similar loop is
 * required anyway.  We could use that BUT we need to update the regexp compiler
 * 'nranges' too.  Work this out a bit more cleanly to save space.
 */

/* XXX: the handling of character range detection is a bit convoluted.
 * Try to simplify and make smaller.
 */

/* XXX: logic for handling character ranges is now incorrect, it will accept
 * e.g. [\d-z] whereas it should croak from it?  SMJS accepts this too, though.
 *
 * Needs a read through and a lot of additional tests.
 */

DUK_LOCAL
void duk__emit_u16_direct_ranges(duk_lexer_ctx *lex_ctx,
                                 duk_re_range_callback gen_range,
                                 void *userdata,
                                 const duk_uint16_t *ranges,
                                 duk_small_int_t num) {
	const duk_uint16_t *ranges_end;

	DUK_UNREF(lex_ctx);

	ranges_end = ranges + num;
	while (ranges < ranges_end) {
		/* mark range 'direct', bypass canonicalization (see Wiki) */
		gen_range(userdata, (duk_codepoint_t) ranges[0], (duk_codepoint_t) ranges[1], 1);
		ranges += 2;
	}
}

DUK_INTERNAL void duk_lexer_parse_re_ranges(duk_lexer_ctx *lex_ctx, duk_re_range_callback gen_range, void *userdata) {
	duk_codepoint_t start = -1;
	duk_codepoint_t ch;
	duk_codepoint_t x;
	duk_bool_t dash = 0;
	duk_small_uint_t adv = 0;

	DUK_DD(DUK_DDPRINT("parsing regexp ranges"));

	for (;;) {
		DUK__ADVANCECHARS(lex_ctx, adv);
		adv = 1;

		x = DUK__L0();

		ch = -1;  /* not strictly necessary, but avoids "uninitialized variable" warnings */
		DUK_UNREF(ch);

		if (x < 0) {
			goto fail_unterm_charclass;
		} else if (x == DUK_ASC_RBRACKET) {
			if (start >= 0) {
				gen_range(userdata, start, start, 0);
			}
			DUK__ADVANCECHARS(lex_ctx, 1);  /* eat ']' before finishing */
			break;
		} else if (x == DUK_ASC_MINUS) {
			if (start >= 0 && !dash && DUK__L1() != DUK_ASC_RBRACKET) {
				/* '-' as a range indicator */
				dash = 1;
				continue;
			} else {
				/* '-' verbatim */
				ch = x;
			}
		} else if (x == DUK_ASC_BACKSLASH) {
			/*
			 *  The escapes are same as outside a character class, except that \b has a
			 *  different meaning, and \B and backreferences are prohibited (see E5
			 *  Section 15.10.2.19).  However, it's difficult to share code because we
			 *  handle e.g. "\n" very differently: here we generate a single character
			 *  range for it.
			 */

			/* XXX: ES2015 surrogate pair handling. */

			x = DUK__L1();

			adv = 2;

			if (x == DUK_ASC_LC_B) {
				/* Note: '\b' in char class is different than outside (assertion),
				 * '\B' is not allowed and is caught by the duk_unicode_is_identifier_part()
				 * check below.
				 */
				ch = 0x0008;
			} else if (x == DUK_ASC_LC_F) {
				ch = 0x000c;
			} else if (x == DUK_ASC_LC_N) {
				ch = 0x000a;
			} else if (x == DUK_ASC_LC_T) {
				ch = 0x0009;
			} else if (x == DUK_ASC_LC_R) {
				ch = 0x000d;
			} else if (x == DUK_ASC_LC_V) {
				ch = 0x000b;
			} else if (x == DUK_ASC_LC_C) {
				x = DUK__L2();
				adv = 3;
				if ((x >= DUK_ASC_LC_A && x <= DUK_ASC_LC_Z) ||
				    (x >= DUK_ASC_UC_A && x <= DUK_ASC_UC_Z)) {
					ch = (x % 32);
				} else {
					goto fail_escape;
				}
			} else if (x == DUK_ASC_LC_X || x == DUK_ASC_LC_U) {
				/* The \u{H+} form is only allowed in Unicode mode which
				 * we don't support yet.
				 */
				ch = duk__lexer_parse_escape(lex_ctx, 0 /*allow_es6*/);
				adv = 0;
			} else if (x == DUK_ASC_LC_D) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_digit,
				                            sizeof(duk_unicode_re_ranges_digit) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (x == DUK_ASC_UC_D) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_not_digit,
				                            sizeof(duk_unicode_re_ranges_not_digit) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (x == DUK_ASC_LC_S) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_white,
				                            sizeof(duk_unicode_re_ranges_white) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (x == DUK_ASC_UC_S) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_not_white,
				                            sizeof(duk_unicode_re_ranges_not_white) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (x == DUK_ASC_LC_W) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_wordchar,
				                            sizeof(duk_unicode_re_ranges_wordchar) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (x == DUK_ASC_UC_W) {
				duk__emit_u16_direct_ranges(lex_ctx,
				                            gen_range,
				                            userdata,
				                            duk_unicode_re_ranges_not_wordchar,
				                            sizeof(duk_unicode_re_ranges_not_wordchar) / sizeof(duk_uint16_t));
				ch = -1;
			} else if (DUK__ISDIGIT(x)) {
				/* DecimalEscape, only \0 is allowed, no leading
				 * zeroes are allowed.
				 *
				 * ES2015 Annex B also allows (maximal match) legacy
				 * octal escapes up to \377 and \8 and \9 are
				 * accepted as literal '8' and '9', also in strict mode.
				 */

#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
				ch = duk__lexer_parse_legacy_octal(lex_ctx, &adv, 0 /*reject_annex_b*/);
				DUK_ASSERT(ch >= 0);  /* no rejections */
#else
				if (x == DUK_ASC_0 && !DUK__ISDIGIT(DUK__L2())) {
					ch = 0x0000;
				} else {
					goto fail_escape;
				}
#endif
#if defined(DUK_USE_ES6_REGEXP_SYNTAX)
			} else if (x >= 0) {
				/* IdentityEscape: ES2015 Annex B allows almost all
				 * source characters here.  Match anything except
				 * EOF here.
				 */
				ch = x;
#else  /* DUK_USE_ES6_REGEXP_SYNTAX */
			} else if (!duk_unicode_is_identifier_part(x)) {
				/* IdentityEscape: ES5.1 doesn't allow identity escape
				 * for identifier part characters, which conflicts with
				 * some real world code.  For example, it doesn't allow
				 * /[\$]/ which is awkward.
				 */
				ch = x;
#endif  /* DUK_USE_ES6_REGEXP_SYNTAX */
			} else {
				goto fail_escape;
			}
		} else {
			/* character represents itself */
			ch = x;
		}

		/* ch is a literal character here or -1 if parsed entity was
		 * an escape such as "\s".
		 */

		if (ch < 0) {
			/* multi-character sets not allowed as part of ranges, see
			 * E5 Section 15.10.2.15, abstract operation CharacterRange.
			 */
			if (start >= 0) {
				if (dash) {
					goto fail_range;
				} else {
					gen_range(userdata, start, start, 0);
					start = -1;
					/* dash is already 0 */
				}
			}
		} else {
			if (start >= 0) {
				if (dash) {
					if (start > ch) {
						goto fail_range;
					}
					gen_range(userdata, start, ch, 0);
					start = -1;
					dash = 0;
				} else {
					gen_range(userdata, start, start, 0);
					start = ch;
					/* dash is already 0 */
				}
			} else {
				start = ch;
			}
		}
	}

	return;

 fail_escape:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_REGEXP_ESCAPE);
	DUK_WO_NORETURN(return;);

 fail_range:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_INVALID_RANGE);
	DUK_WO_NORETURN(return;);

 fail_unterm_charclass:
	DUK_ERROR_SYNTAX(lex_ctx->thr, DUK_STR_UNTERMINATED_CHARCLASS);
	DUK_WO_NORETURN(return;);
}

#endif  /* DUK_USE_REGEXP_SUPPORT */

/* automatic undefs */
#undef DUK__ADVANCEBYTES
#undef DUK__ADVANCECHARS
#undef DUK__ADVTOK
#undef DUK__APPENDBUFFER
#undef DUK__APPENDBUFFER_ASCII
#undef DUK__INITBUFFER
#undef DUK__ISDIGIT
#undef DUK__ISDIGIT03
#undef DUK__ISDIGIT47
#undef DUK__ISHEXDIGIT
#undef DUK__ISOCTDIGIT
#undef DUK__L0
#undef DUK__L1
#undef DUK__L2
#undef DUK__L3
#undef DUK__L4
#undef DUK__L5
#undef DUK__LOOKUP
#undef DUK__MAX_RE_DECESC_DIGITS
#undef DUK__MAX_RE_QUANT_DIGITS
/*
 *  Number-to-string and string-to-number conversions.
 *
 *  Slow path number-to-string and string-to-number conversion is based on
 *  a Dragon4 variant, with fast paths for small integers.  Big integer
 *  arithmetic is needed for guaranteeing that the conversion is correct
 *  and uses a minimum number of digits.  The big number arithmetic has a
 *  fixed maximum size and does not require dynamic allocations.
 *
 *  See: doc/number-conversion.rst.
 */

/* #include duk_internal.h -> already included */

#define DUK__IEEE_DOUBLE_EXP_BIAS  1023
#define DUK__IEEE_DOUBLE_EXP_MIN   (-1022)   /* biased exp == 0 -> denormal, exp -1022 */

#define DUK__DIGITCHAR(x)  duk_lc_digits[(x)]

/*
 *  Tables generated with util/gennumdigits.py.
 *
 *  duk__str2num_digits_for_radix indicates, for each radix, how many input
 *  digits should be considered significant for string-to-number conversion.
 *  The input is also padded to this many digits to give the Dragon4
 *  conversion enough (apparent) precision to work with.
 *
 *  duk__str2num_exp_limits indicates, for each radix, the radix-specific
 *  minimum/maximum exponent values (for a Dragon4 integer mantissa)
 *  below and above which the number is guaranteed to underflow to zero
 *  or overflow to Infinity.  This allows parsing to keep bigint values
 *  bounded.
 */

DUK_LOCAL const duk_uint8_t duk__str2num_digits_for_radix[] = {
	69, 44, 35, 30, 27, 25, 23, 22, 20, 20,    /* 2 to 11 */
	20, 19, 19, 18, 18, 17, 17, 17, 16, 16,    /* 12 to 21 */
	16, 16, 16, 15, 15, 15, 15, 15, 15, 14,    /* 22 to 31 */
	14, 14, 14, 14, 14                         /* 31 to 36 */
};

typedef struct {
	duk_int16_t upper;
	duk_int16_t lower;
} duk__exp_limits;

DUK_LOCAL const duk__exp_limits duk__str2num_exp_limits[] = {
	{ 957, -1147 }, { 605, -725 },  { 479, -575 },  { 414, -496 },
	{ 372, -446 },  { 342, -411 },  { 321, -384 },  { 304, -364 },
	{ 291, -346 },  { 279, -334 },  { 268, -323 },  { 260, -312 },
	{ 252, -304 },  { 247, -296 },  { 240, -289 },  { 236, -283 },
	{ 231, -278 },  { 227, -273 },  { 223, -267 },  { 220, -263 },
	{ 216, -260 },  { 213, -256 },  { 210, -253 },  { 208, -249 },
	{ 205, -246 },  { 203, -244 },  { 201, -241 },  { 198, -239 },
	{ 196, -237 },  { 195, -234 },  { 193, -232 },  { 191, -230 },
	{ 190, -228 },  { 188, -226 },  { 187, -225 },
};

/*
 *  Limited functionality bigint implementation.
 *
 *  Restricted to non-negative numbers with less than 32 * DUK__BI_MAX_PARTS bits,
 *  with the caller responsible for ensuring this is never exceeded.  No memory
 *  allocation (except stack) is needed for bigint computation.  Operations
 *  have been tailored for number conversion needs.
 *
 *  Argument order is "assignment order", i.e. target first, then arguments:
 *  x <- y * z  -->  duk__bi_mul(x, y, z);
 */

/* This upper value has been experimentally determined; debug build will check
 * bigint size with assertions.
 */
#define DUK__BI_MAX_PARTS  37  /* 37x32 = 1184 bits */

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
#define DUK__BI_PRINT(name,x)  duk__bi_print((name),(x))
#else
#define DUK__BI_PRINT(name,x)
#endif

/* Current size is about 152 bytes. */
typedef struct {
	duk_small_int_t n;
	duk_uint32_t v[DUK__BI_MAX_PARTS];  /* low to high */
} duk__bigint;

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
DUK_LOCAL void duk__bi_print(const char *name, duk__bigint *x) {
	/* Overestimate required size; debug code so not critical to be tight. */
	char buf[DUK__BI_MAX_PARTS * 9 + 64];
	char *p = buf;
	duk_small_int_t i;

	/* No NUL term checks in this debug code. */
	p += DUK_SPRINTF(p, "%p n=%ld", (void *) x, (long) x->n);
	if (x->n == 0) {
		p += DUK_SPRINTF(p, " 0");
	}
	for (i = x->n - 1; i >= 0; i--) {
		p += DUK_SPRINTF(p, " %08lx", (unsigned long) x->v[i]);
	}

	DUK_DDD(DUK_DDDPRINT("%s: %s", (const char *) name, (const char *) buf));
}
#endif

#if defined(DUK_USE_ASSERTIONS)
DUK_LOCAL duk_small_int_t duk__bi_is_valid(duk__bigint *x) {
	return (duk_small_int_t)
	       ( ((x->n >= 0) && (x->n <= DUK__BI_MAX_PARTS)) /* is valid size */ &&
	         ((x->n == 0) || (x->v[x->n - 1] != 0)) /* is normalized */ );
}
#endif

DUK_LOCAL void duk__bi_normalize(duk__bigint *x) {
	duk_small_int_t i;

	for (i = x->n - 1; i >= 0; i--) {
		if (x->v[i] != 0) {
			break;
		}
	}

	/* Note: if 'x' is zero, x->n becomes 0 here */
	x->n = i + 1;
	DUK_ASSERT(duk__bi_is_valid(x));
}

/* x <- y */
DUK_LOCAL void duk__bi_copy(duk__bigint *x, duk__bigint *y) {
	duk_small_int_t n;

	n = y->n;
	x->n = n;
	/* No need to special case n == 0. */
	duk_memcpy((void *) x->v, (const void *) y->v, (size_t) (sizeof(duk_uint32_t) * (size_t) n));
}

DUK_LOCAL void duk__bi_set_small(duk__bigint *x, duk_uint32_t v) {
	if (v == 0U) {
		x->n = 0;
	} else {
		x->n = 1;
		x->v[0] = v;
	}
	DUK_ASSERT(duk__bi_is_valid(x));
}

/* Return value: <0  <=>  x < y
 *                0  <=>  x == y
 *               >0  <=>  x > y
 */
DUK_LOCAL int duk__bi_compare(duk__bigint *x, duk__bigint *y) {
	duk_small_int_t i, nx, ny;
	duk_uint32_t tx, ty;

	DUK_ASSERT(duk__bi_is_valid(x));
	DUK_ASSERT(duk__bi_is_valid(y));

	nx = x->n;
	ny = y->n;
	if (nx > ny) {
		goto ret_gt;
	}
	if (nx < ny) {
		goto ret_lt;
	}
	for (i = nx - 1; i >= 0; i--) {
		tx = x->v[i];
		ty = y->v[i];

		if (tx > ty) {
			goto ret_gt;
		}
		if (tx < ty) {
			goto ret_lt;
		}
	}

	return 0;

 ret_gt:
	return 1;

 ret_lt:
	return -1;
}

/* x <- y + z */
#if defined(DUK_USE_64BIT_OPS)
DUK_LOCAL void duk__bi_add(duk__bigint *x, duk__bigint *y, duk__bigint *z) {
	duk_uint64_t tmp;
	duk_small_int_t i, ny, nz;

	DUK_ASSERT(duk__bi_is_valid(y));
	DUK_ASSERT(duk__bi_is_valid(z));

	if (z->n > y->n) {
		duk__bigint *t;
		t = y; y = z; z = t;
	}
	DUK_ASSERT(y->n >= z->n);

	ny = y->n; nz = z->n;
	tmp = 0U;
	for (i = 0; i < ny; i++) {
		DUK_ASSERT(i < DUK__BI_MAX_PARTS);
		tmp += y->v[i];
		if (i < nz) {
			tmp += z->v[i];
		}
		x->v[i] = (duk_uint32_t) (tmp & 0xffffffffUL);
		tmp = tmp >> 32;
	}
	if (tmp != 0U) {
		DUK_ASSERT(i < DUK__BI_MAX_PARTS);
		x->v[i++] = (duk_uint32_t) tmp;
	}
	x->n = i;
	DUK_ASSERT(x->n <= DUK__BI_MAX_PARTS);

	/* no need to normalize */
	DUK_ASSERT(duk__bi_is_valid(x));
}
#else  /* DUK_USE_64BIT_OPS */
DUK_LOCAL void duk__bi_add(duk__bigint *x, duk__bigint *y, duk__bigint *z) {
	duk_uint32_t carry, tmp1, tmp2;
	duk_small_int_t i, ny, nz;

	DUK_ASSERT(duk__bi_is_valid(y));
	DUK_ASSERT(duk__bi_is_valid(z));

	if (z->n > y->n) {
		duk__bigint *t;
		t = y; y = z; z = t;
	}
	DUK_ASSERT(y->n >= z->n);

	ny = y->n; nz = z->n;
	carry = 0U;
	for (i = 0; i < ny; i++) {
		/* Carry is detected based on wrapping which relies on exact 32-bit
		 * types.
		 */
		DUK_ASSERT(i < DUK__BI_MAX_PARTS);
		tmp1 = y->v[i];
		tmp2 = tmp1;
		if (i < nz) {
			tmp2 += z->v[i];
		}

		/* Careful with carry condition:
		 *  - If carry not added: 0x12345678 + 0 + 0xffffffff = 0x12345677 (< 0x12345678)
		 *  - If carry added:     0x12345678 + 1 + 0xffffffff = 0x12345678 (== 0x12345678)
		 */
		if (carry) {
			tmp2++;
			carry = (tmp2 <= tmp1 ? 1U : 0U);
		} else {
			carry = (tmp2 < tmp1 ? 1U : 0U);
		}

		x->v[i] = tmp2;
	}
	if (carry) {
		DUK_ASSERT(i < DUK__BI_MAX_PARTS);
		DUK_ASSERT(carry == 1U);
		x->v[i++] = carry;
	}
	x->n = i;
	DUK_ASSERT(x->n <= DUK__BI_MAX_PARTS);

	/* no need to normalize */
	DUK_ASSERT(duk__bi_is_valid(x));
}
#endif  /* DUK_USE_64BIT_OPS */

/* x <- y + z */
DUK_LOCAL void duk__bi_add_small(duk__bigint *x, duk__bigint *y, duk_uint32_t z) {
	duk__bigint tmp;

	DUK_ASSERT(duk__bi_is_valid(y));

	/* XXX: this could be optimized; there is only one call site now though */
	duk__bi_set_small(&tmp, z);
	duk__bi_add(x, y, &tmp);

	DUK_ASSERT(duk__bi_is_valid(x));
}

#if 0  /* unused */
/* x <- x + y, use t as temp */
DUK_LOCAL void duk__bi_add_copy(duk__bigint *x, duk__bigint *y, duk__bigint *t) {
	duk__bi_add(t, x, y);
	duk__bi_copy(x, t);
}
#endif

/* x <- y - z, require x >= y => z >= 0, i.e. y >= z */
#if defined(DUK_USE_64BIT_OPS)
DUK_LOCAL void duk__bi_sub(duk__bigint *x, duk__bigint *y, duk__bigint *z) {
	duk_small_int_t i, ny, nz;
	duk_uint32_t ty, tz;
	duk_int64_t tmp;

	DUK_ASSERT(duk__bi_is_valid(y));
	DUK_ASSERT(duk__bi_is_valid(z));
	DUK_ASSERT(duk__bi_compare(y, z) >= 0);
	DUK_ASSERT(y->n >= z->n);

	ny = y->n; nz = z->n;
	tmp = 0;
	for (i = 0; i < ny; i++) {
		ty = y->v[i];
		if (i < nz) {
			tz = z->v[i];
		} else {
			tz = 0;
		}
		tmp = (duk_int64_t) ty - (duk_int64_t) tz + tmp;
		x->v[i] = (duk_uint32_t) ((duk_uint64_t) tmp & 0xffffffffUL);
		tmp = tmp >> 32;  /* 0 or -1 */
	}
	DUK_ASSERT(tmp == 0);

	x->n = i;
	duk__bi_normalize(x);  /* need to normalize, may even cancel to 0 */
	DUK_ASSERT(duk__bi_is_valid(x));
}
#else
DUK_LOCAL void duk__bi_sub(duk__bigint *x, duk__bigint *y, duk__bigint *z) {
	duk_small_int_t i, ny, nz;
	duk_uint32_t tmp1, tmp2, borrow;

	DUK_ASSERT(duk__bi_is_valid(y));
	DUK_ASSERT(duk__bi_is_valid(z));
	DUK_ASSERT(duk__bi_compare(y, z) >= 0);
	DUK_ASSERT(y->n >= z->n);

	ny = y->n; nz = z->n;
	borrow = 0U;
	for (i = 0; i < ny; i++) {
		/* Borrow is detected based on wrapping which relies on exact 32-bit
		 * types.
		 */
		tmp1 = y->v[i];
		tmp2 = tmp1;
		if (i < nz) {
			tmp2 -= z->v[i];
		}

		/* Careful with borrow condition:
		 *  - If borrow not subtracted: 0x12345678 - 0 - 0xffffffff = 0x12345679 (> 0x12345678)
		 *  - If borrow subtracted:     0x12345678 - 1 - 0xffffffff = 0x12345678 (== 0x12345678)
		 */
		if (borrow) {
			tmp2--;
			borrow = (tmp2 >= tmp1 ? 1U : 0U);
		} else {
			borrow = (tmp2 > tmp1 ? 1U : 0U);
		}

		x->v[i] = tmp2;
	}
	DUK_ASSERT(borrow == 0U);

	x->n = i;
	duk__bi_normalize(x);  /* need to normalize, may even cancel to 0 */
	DUK_ASSERT(duk__bi_is_valid(x));
}
#endif

#if 0  /* unused */
/* x <- y - z */
DUK_LOCAL void duk__bi_sub_small(duk__bigint *x, duk__bigint *y, duk_uint32_t z) {
	duk__bigint tmp;

	DUK_ASSERT(duk__bi_is_valid(y));

	/* XXX: this could be optimized */
	duk__bi_set_small(&tmp, z);
	duk__bi_sub(x, y, &tmp);

	DUK_ASSERT(duk__bi_is_valid(x));
}
#endif

/* x <- x - y, use t as temp */
DUK_LOCAL void duk__bi_sub_copy(duk__bigint *x, duk__bigint *y, duk__bigint *t) {
	duk__bi_sub(t, x, y);
	duk__bi_copy(x, t);
}

/* x <- y * z */
DUK_LOCAL void duk__bi_mul(duk__bigint *x, duk__bigint *y, duk__bigint *z) {
	duk_small_int_t i, j, nx, nz;

	DUK_ASSERT(duk__bi_is_valid(y));
	DUK_ASSERT(duk__bi_is_valid(z));

	nx = y->n + z->n;  /* max possible */
	DUK_ASSERT(nx <= DUK__BI_MAX_PARTS);

	if (nx == 0) {
		/* Both inputs are zero; cases where only one is zero can go
		 * through main algorithm.
		 */
		x->n = 0;
		return;
	}

	duk_memzero((void *) x->v, (size_t) (sizeof(duk_uint32_t) * (size_t) nx));
	x->n = nx;

	nz = z->n;
	for (i = 0; i < y->n; i++) {
#if defined(DUK_USE_64BIT_OPS)
		duk_uint64_t tmp = 0U;
		for (j = 0; j < nz; j++) {
			tmp += (duk_uint64_t) y->v[i] * (duk_uint64_t) z->v[j] + x->v[i+j];
			x->v[i+j] = (duk_uint32_t) (tmp & 0xffffffffUL);
			tmp = tmp >> 32;
		}
		if (tmp > 0) {
			DUK_ASSERT(i + j < nx);
			DUK_ASSERT(i + j < DUK__BI_MAX_PARTS);
			DUK_ASSERT(x->v[i+j] == 0U);
			x->v[i+j] = (duk_uint32_t) tmp;
		}
#else
		/*
		 *  Multiply + add + carry for 32-bit components using only 16x16->32
		 *  multiplies and carry detection based on unsigned overflow.
		 *
		 *    1st mult, 32-bit: (A*2^16 + B)
		 *    2nd mult, 32-bit: (C*2^16 + D)
		 *    3rd add, 32-bit: E
		 *    4th add, 32-bit: F
		 *
		 *      (AC*2^16 + B) * (C*2^16 + D) + E + F
		 *    = AC*2^32 + AD*2^16 + BC*2^16 + BD + E + F
		 *    = AC*2^32 + (AD + BC)*2^16 + (BD + E + F)
		 *    = AC*2^32 + AD*2^16 + BC*2^16 + (BD + E + F)
		 */
		duk_uint32_t a, b, c, d, e, f;
		duk_uint32_t r, s, t;

		a = y->v[i]; b = a & 0xffffUL; a = a >> 16;

		f = 0;
		for (j = 0; j < nz; j++) {
			c = z->v[j]; d = c & 0xffffUL; c = c >> 16;
			e = x->v[i+j];

			/* build result as: (r << 32) + s: start with (BD + E + F) */
			r = 0;
			s = b * d;

			/* add E */
			t = s + e;
			if (t < s) { r++; }  /* carry */
			s = t;

			/* add F */
			t = s + f;
			if (t < s) { r++; }  /* carry */
			s = t;

			/* add BC*2^16 */
			t = b * c;
			r += (t >> 16);
			t = s + ((t & 0xffffUL) << 16);
			if (t < s) { r++; }  /* carry */
			s = t;

			/* add AD*2^16 */
			t = a * d;
			r += (t >> 16);
			t = s + ((t & 0xffffUL) << 16);
			if (t < s) { r++; }  /* carry */
			s = t;

			/* add AC*2^32 */
			t = a * c;
			r += t;

			DUK_DDD(DUK_DDDPRINT("ab=%08lx cd=%08lx ef=%08lx -> rs=%08lx %08lx",
			                     (unsigned long) y->v[i], (unsigned long) z->v[j],
			                     (unsigned long) x->v[i+j], (unsigned long) r,
			                     (unsigned long) s));

			x->v[i+j] = s;
			f = r;
		}
		if (f > 0U) {
			DUK_ASSERT(i + j < nx);
			DUK_ASSERT(i + j < DUK__BI_MAX_PARTS);
			DUK_ASSERT(x->v[i+j] == 0U);
			x->v[i+j] = (duk_uint32_t) f;
		}
#endif  /* DUK_USE_64BIT_OPS */
	}

	duk__bi_normalize(x);
	DUK_ASSERT(duk__bi_is_valid(x));
}

/* x <- y * z */
DUK_LOCAL void duk__bi_mul_small(duk__bigint *x, duk__bigint *y, duk_uint32_t z) {
	duk__bigint tmp;

	DUK_ASSERT(duk__bi_is_valid(y));

	/* XXX: this could be optimized */
	duk__bi_set_small(&tmp, z);
	duk__bi_mul(x, y, &tmp);

	DUK_ASSERT(duk__bi_is_valid(x));
}

/* x <- x * y, use t as temp */
DUK_LOCAL void duk__bi_mul_copy(duk__bigint *x, duk__bigint *y, duk__bigint *t) {
	duk__bi_mul(t, x, y);
	duk__bi_copy(x, t);
}

/* x <- x * y, use t as temp */
DUK_LOCAL void duk__bi_mul_small_copy(duk__bigint *x, duk_uint32_t y, duk__bigint *t) {
	duk__bi_mul_small(t, x, y);
	duk__bi_copy(x, t);
}

DUK_LOCAL int duk__bi_is_even(duk__bigint *x) {
	DUK_ASSERT(duk__bi_is_valid(x));
	return (x->n == 0) || ((x->v[0] & 0x01) == 0);
}

DUK_LOCAL int duk__bi_is_zero(duk__bigint *x) {
	DUK_ASSERT(duk__bi_is_valid(x));
	return (x->n == 0);  /* this is the case for normalized numbers */
}

/* Bigint is 2^52.  Used to detect normalized IEEE double mantissa values
 * which are at the lowest edge (next floating point value downwards has
 * a different exponent).  The lowest mantissa has the form:
 *
 *     1000........000    (52 zeroes; only "hidden bit" is set)
 */
DUK_LOCAL duk_small_int_t duk__bi_is_2to52(duk__bigint *x) {
	DUK_ASSERT(duk__bi_is_valid(x));
	return (duk_small_int_t)
	        (x->n == 2) && (x->v[0] == 0U) && (x->v[1] == (1U << (52-32)));
}

/* x <- (1<<y) */
DUK_LOCAL void duk__bi_twoexp(duk__bigint *x, duk_small_int_t y) {
	duk_small_int_t n, r;

	n = (y / 32) + 1;
	DUK_ASSERT(n > 0);
	r = y % 32;
	duk_memzero((void *) x->v, sizeof(duk_uint32_t) * (size_t) n);
	x->n = n;
	x->v[n - 1] = (((duk_uint32_t) 1) << r);
}

/* x <- b^y; use t1 and t2 as temps */
DUK_LOCAL void duk__bi_exp_small(duk__bigint *x, duk_small_int_t b, duk_small_int_t y, duk__bigint *t1, duk__bigint *t2) {
	/* Fast path the binary case */

	DUK_ASSERT(x != t1 && x != t2 && t1 != t2);  /* distinct bignums, easy mistake to make */
	DUK_ASSERT(b >= 0);
	DUK_ASSERT(y >= 0);

	if (b == 2) {
		duk__bi_twoexp(x, y);
		return;
	}

	/* http://en.wikipedia.org/wiki/Exponentiation_by_squaring */

	DUK_DDD(DUK_DDDPRINT("exp_small: b=%ld, y=%ld", (long) b, (long) y));

	duk__bi_set_small(x, 1);
	duk__bi_set_small(t1, (duk_uint32_t) b);
	for (;;) {
		/* Loop structure ensures that we don't compute t1^2 unnecessarily
		 * on the final round, as that might create a bignum exceeding the
		 * current DUK__BI_MAX_PARTS limit.
		 */
		if (y & 0x01) {
			duk__bi_mul_copy(x, t1, t2);
		}
		y = y >> 1;
		if (y == 0) {
			break;
		}
		duk__bi_mul_copy(t1, t1, t2);
	}

	DUK__BI_PRINT("exp_small result", x);
}

/*
 *  A Dragon4 number-to-string variant, based on:
 *
 *    Guy L. Steele Jr., Jon L. White: "How to Print Floating-Point Numbers
 *    Accurately"
 *
 *    Robert G. Burger, R. Kent Dybvig: "Printing Floating-Point Numbers
 *    Quickly and Accurately"
 *
 *  The current algorithm is based on Figure 1 of the Burger-Dybvig paper,
 *  i.e. the base implementation without logarithm estimation speedups
 *  (these would increase code footprint considerably).  Fixed-format output
 *  does not follow the suggestions in the paper; instead, we generate an
 *  extra digit and round-with-carry.
 *
 *  The same algorithm is used for number parsing (with b=10 and B=2)
 *  by generating one extra digit and doing rounding manually.
 *
 *  See doc/number-conversion.rst for limitations.
 */

/* Maximum number of digits generated. */
#define DUK__MAX_OUTPUT_DIGITS          1040  /* (Number.MAX_VALUE).toString(2).length == 1024, + slack */

/* Maximum number of characters in formatted value. */
#define DUK__MAX_FORMATTED_LENGTH       1040  /* (-Number.MAX_VALUE).toString(2).length == 1025, + slack */

/* Number and (minimum) size of bigints in the nc_ctx structure. */
#define DUK__NUMCONV_CTX_NUM_BIGINTS    7
#define DUK__NUMCONV_CTX_BIGINTS_SIZE   (sizeof(duk__bigint) * DUK__NUMCONV_CTX_NUM_BIGINTS)

typedef struct {
	/* Currently about 7*152 = 1064 bytes.  The space for these
	 * duk__bigints is used also as a temporary buffer for generating
	 * the final string.  This is a bit awkard; a union would be
	 * more correct.
	 */
	duk__bigint f, r, s, mp, mm, t1, t2;

	duk_small_int_t is_s2n;        /* if 1, doing a string-to-number; else doing a number-to-string */
	duk_small_int_t is_fixed;      /* if 1, doing a fixed format output (not free format) */
	duk_small_int_t req_digits;    /* requested number of output digits; 0 = free-format */
	duk_small_int_t abs_pos;       /* digit position is absolute, not relative */
	duk_small_int_t e;             /* exponent for 'f' */
	duk_small_int_t b;             /* input radix */
	duk_small_int_t B;             /* output radix */
	duk_small_int_t k;             /* see algorithm */
	duk_small_int_t low_ok;        /* see algorithm */
	duk_small_int_t high_ok;       /* see algorithm */
	duk_small_int_t unequal_gaps;  /* m+ != m- (very rarely) */

	/* Buffer used for generated digits, values are in the range [0,B-1]. */
	duk_uint8_t digits[DUK__MAX_OUTPUT_DIGITS];
	duk_small_int_t count;  /* digit count */
} duk__numconv_stringify_ctx;

/* Note: computes with 'idx' in assertions, so caller beware.
 * 'idx' is preincremented, i.e. '1' on first call, because it
 * is more convenient for the caller.
 */
#define DUK__DRAGON4_OUTPUT_PREINC(nc_ctx,preinc_idx,x)  do { \
		DUK_ASSERT((preinc_idx) - 1 >= 0); \
		DUK_ASSERT((preinc_idx) - 1 < DUK__MAX_OUTPUT_DIGITS); \
		((nc_ctx)->digits[(preinc_idx) - 1]) = (duk_uint8_t) (x); \
	} while (0)

DUK_LOCAL duk_size_t duk__dragon4_format_uint32(duk_uint8_t *buf, duk_uint32_t x, duk_small_int_t radix) {
	duk_uint8_t *p;
	duk_size_t len;
	duk_small_int_t dig;
	duk_uint32_t t;

	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(radix >= 2 && radix <= 36);

	/* A 32-bit unsigned integer formats to at most 32 digits (the
	 * worst case happens with radix == 2).  Output the digits backwards,
	 * and use a memmove() to get them in the right place.
	 */

	p = buf + 32;
	for (;;) {
		t = x / (duk_uint32_t) radix;
		dig = (duk_small_int_t) (x - t * (duk_uint32_t) radix);
		x = t;

		DUK_ASSERT(dig >= 0 && dig < 36);
		*(--p) = DUK__DIGITCHAR(dig);

		if (x == 0) {
			break;
		}
	}
	len = (duk_size_t) ((buf + 32) - p);

	duk_memmove((void *) buf, (const void *) p, (size_t) len);

	return len;
}

DUK_LOCAL void duk__dragon4_prepare(duk__numconv_stringify_ctx *nc_ctx) {
	duk_small_int_t lowest_mantissa;

#if 1
	/* Assume IEEE round-to-even, so that shorter encoding can be used
	 * when round-to-even would produce correct result.  By removing
	 * this check (and having low_ok == high_ok == 0) the results would
	 * still be accurate but in some cases longer than necessary.
	 */
	if (duk__bi_is_even(&nc_ctx->f)) {
		DUK_DDD(DUK_DDDPRINT("f is even"));
		nc_ctx->low_ok = 1;
		nc_ctx->high_ok = 1;
	} else {
		DUK_DDD(DUK_DDDPRINT("f is odd"));
		nc_ctx->low_ok = 0;
		nc_ctx->high_ok = 0;
	}
#else
	/* Note: not honoring round-to-even should work but now generates incorrect
	 * results.  For instance, 1e23 serializes to "a000...", i.e. the first digit
	 * equals the radix (10).  Scaling stops one step too early in this case.
	 * Don't know why this is the case, but since this code path is unused, it
	 * doesn't matter.
	 */
	nc_ctx->low_ok = 0;
	nc_ctx->high_ok = 0;
#endif

	/* For string-to-number, pretend we never have the lowest mantissa as there
	 * is no natural "precision" for inputs.  Having lowest_mantissa == 0, we'll
	 * fall into the base cases for both e >= 0 and e < 0.
	 */
	if (nc_ctx->is_s2n) {
		lowest_mantissa = 0;
	} else {
		lowest_mantissa = duk__bi_is_2to52(&nc_ctx->f);
	}

	nc_ctx->unequal_gaps = 0;
	if (nc_ctx->e >= 0) {
		/* exponent non-negative (and thus not minimum exponent) */

		if (lowest_mantissa) {
			/* (>= e 0) AND (= f (expt b (- p 1)))
			 *
			 * be <- (expt b e) == b^e
			 * be1 <- (* be b) == (expt b (+ e 1)) == b^(e+1)
			 * r <- (* f be1 2) == 2 * f * b^(e+1)    [if b==2 -> f * b^(e+2)]
			 * s <- (* b 2)                           [if b==2 -> 4]
			 * m+ <- be1 == b^(e+1)
			 * m- <- be == b^e
			 * k <- 0
			 * B <- B
			 * low_ok <- round
			 * high_ok <- round
			 */

			DUK_DDD(DUK_DDDPRINT("non-negative exponent (not smallest exponent); "
			                     "lowest mantissa value for this exponent -> "
			                     "unequal gaps"));

			duk__bi_exp_small(&nc_ctx->mm, nc_ctx->b, nc_ctx->e, &nc_ctx->t1, &nc_ctx->t2);  /* mm <- b^e */
			duk__bi_mul_small(&nc_ctx->mp, &nc_ctx->mm, (duk_uint32_t) nc_ctx->b);           /* mp <- b^(e+1) */
			duk__bi_mul_small(&nc_ctx->t1, &nc_ctx->f, 2);
			duk__bi_mul(&nc_ctx->r, &nc_ctx->t1, &nc_ctx->mp);              /* r <- (2 * f) * b^(e+1) */
			duk__bi_set_small(&nc_ctx->s, (duk_uint32_t) (nc_ctx->b * 2));  /* s <- 2 * b */
			nc_ctx->unequal_gaps = 1;
		} else {
			/* (>= e 0) AND (not (= f (expt b (- p 1))))
			 *
			 * be <- (expt b e) == b^e
			 * r <- (* f be 2) == 2 * f * b^e    [if b==2 -> f * b^(e+1)]
			 * s <- 2
			 * m+ <- be == b^e
			 * m- <- be == b^e
			 * k <- 0
			 * B <- B
			 * low_ok <- round
			 * high_ok <- round
			 */

			DUK_DDD(DUK_DDDPRINT("non-negative exponent (not smallest exponent); "
			                     "not lowest mantissa for this exponent -> "
			                     "equal gaps"));

			duk__bi_exp_small(&nc_ctx->mm, nc_ctx->b, nc_ctx->e, &nc_ctx->t1, &nc_ctx->t2);  /* mm <- b^e */
			duk__bi_copy(&nc_ctx->mp, &nc_ctx->mm);                /* mp <- b^e */
			duk__bi_mul_small(&nc_ctx->t1, &nc_ctx->f, 2);
			duk__bi_mul(&nc_ctx->r, &nc_ctx->t1, &nc_ctx->mp);     /* r <- (2 * f) * b^e */
			duk__bi_set_small(&nc_ctx->s, 2);                      /* s <- 2 */
		}
	} else {
		/* When doing string-to-number, lowest_mantissa is always 0 so
		 * the exponent check, while incorrect, won't matter.
		 */
		if (nc_ctx->e > DUK__IEEE_DOUBLE_EXP_MIN /*not minimum exponent*/ &&
		    lowest_mantissa /* lowest mantissa for this exponent*/) {
			/* r <- (* f b 2)                                [if b==2 -> (* f 4)]
			 * s <- (* (expt b (- 1 e)) 2) == b^(1-e) * 2    [if b==2 -> b^(2-e)]
			 * m+ <- b == 2
			 * m- <- 1
			 * k <- 0
			 * B <- B
			 * low_ok <- round
			 * high_ok <- round
			 */

			DUK_DDD(DUK_DDDPRINT("negative exponent; not minimum exponent and "
			                     "lowest mantissa for this exponent -> "
			                     "unequal gaps"));

			duk__bi_mul_small(&nc_ctx->r, &nc_ctx->f, (duk_uint32_t) (nc_ctx->b * 2));  /* r <- (2 * b) * f */
			duk__bi_exp_small(&nc_ctx->t1, nc_ctx->b, 1 - nc_ctx->e, &nc_ctx->s, &nc_ctx->t2);  /* NB: use 's' as temp on purpose */
			duk__bi_mul_small(&nc_ctx->s, &nc_ctx->t1, 2);             /* s <- b^(1-e) * 2 */
			duk__bi_set_small(&nc_ctx->mp, 2);
			duk__bi_set_small(&nc_ctx->mm, 1);
			nc_ctx->unequal_gaps = 1;
		} else {
			/* r <- (* f 2)
			 * s <- (* (expt b (- e)) 2) == b^(-e) * 2    [if b==2 -> b^(1-e)]
			 * m+ <- 1
			 * m- <- 1
			 * k <- 0
			 * B <- B
			 * low_ok <- round
			 * high_ok <- round
			 */

			DUK_DDD(DUK_DDDPRINT("negative exponent; minimum exponent or not "
			                     "lowest mantissa for this exponent -> "
			                     "equal gaps"));

			duk__bi_mul_small(&nc_ctx->r, &nc_ctx->f, 2);            /* r <- 2 * f */
			duk__bi_exp_small(&nc_ctx->t1, nc_ctx->b, -nc_ctx->e, &nc_ctx->s, &nc_ctx->t2);  /* NB: use 's' as temp on purpose */
			duk__bi_mul_small(&nc_ctx->s, &nc_ctx->t1, 2);           /* s <- b^(-e) * 2 */
			duk__bi_set_small(&nc_ctx->mp, 1);
			duk__bi_set_small(&nc_ctx->mm, 1);
		}
	}
}

DUK_LOCAL void duk__dragon4_scale(duk__numconv_stringify_ctx *nc_ctx) {
	duk_small_int_t k = 0;

	/* This is essentially the 'scale' algorithm, with recursion removed.
	 * Note that 'k' is either correct immediately, or will move in one
	 * direction in the loop.  There's no need to do the low/high checks
	 * on every round (like the Scheme algorithm does).
	 *
	 * The scheme algorithm finds 'k' and updates 's' simultaneously,
	 * while the logical algorithm finds 'k' with 's' having its initial
	 * value, after which 's' is updated separately (see the Burger-Dybvig
	 * paper, Section 3.1, steps 2 and 3).
	 *
	 * The case where m+ == m- (almost always) is optimized for, because
	 * it reduces the bigint operations considerably and almost always
	 * applies.  The scale loop only needs to work with m+, so this works.
	 */

	/* XXX: this algorithm could be optimized quite a lot by using e.g.
	 * a logarithm based estimator for 'k' and performing B^n multiplication
	 * using a lookup table or using some bit-representation based exp
	 * algorithm.  Currently we just loop, with significant performance
	 * impact for very large and very small numbers.
	 */

	DUK_DDD(DUK_DDDPRINT("scale: B=%ld, low_ok=%ld, high_ok=%ld",
	                     (long) nc_ctx->B, (long) nc_ctx->low_ok, (long) nc_ctx->high_ok));
	DUK__BI_PRINT("r(init)", &nc_ctx->r);
	DUK__BI_PRINT("s(init)", &nc_ctx->s);
	DUK__BI_PRINT("mp(init)", &nc_ctx->mp);
	DUK__BI_PRINT("mm(init)", &nc_ctx->mm);

	for (;;) {
		DUK_DDD(DUK_DDDPRINT("scale loop (inc k), k=%ld", (long) k));
		DUK__BI_PRINT("r", &nc_ctx->r);
		DUK__BI_PRINT("s", &nc_ctx->s);
		DUK__BI_PRINT("m+", &nc_ctx->mp);
		DUK__BI_PRINT("m-", &nc_ctx->mm);

		duk__bi_add(&nc_ctx->t1, &nc_ctx->r, &nc_ctx->mp);  /* t1 = (+ r m+) */
		if (duk__bi_compare(&nc_ctx->t1, &nc_ctx->s) >= (nc_ctx->high_ok ? 0 : 1)) {
			DUK_DDD(DUK_DDDPRINT("k is too low"));
			/* r <- r
			 * s <- (* s B)
			 * m+ <- m+
			 * m- <- m-
			 * k <- (+ k 1)
			 */

			duk__bi_mul_small_copy(&nc_ctx->s, (duk_uint32_t) nc_ctx->B, &nc_ctx->t1);
			k++;
		} else {
			break;
		}
	}

	/* k > 0 -> k was too low, and cannot be too high */
	if (k > 0) {
		goto skip_dec_k;
	}

	for (;;) {
		DUK_DDD(DUK_DDDPRINT("scale loop (dec k), k=%ld", (long) k));
		DUK__BI_PRINT("r", &nc_ctx->r);
		DUK__BI_PRINT("s", &nc_ctx->s);
		DUK__BI_PRINT("m+", &nc_ctx->mp);
		DUK__BI_PRINT("m-", &nc_ctx->mm);

		duk__bi_add(&nc_ctx->t1, &nc_ctx->r, &nc_ctx->mp);  /* t1 = (+ r m+) */
		duk__bi_mul_small(&nc_ctx->t2, &nc_ctx->t1, (duk_uint32_t) nc_ctx->B);   /* t2 = (* (+ r m+) B) */
		if (duk__bi_compare(&nc_ctx->t2, &nc_ctx->s) <= (nc_ctx->high_ok ? -1 : 0)) {
			DUK_DDD(DUK_DDDPRINT("k is too high"));
			/* r <- (* r B)
			 * s <- s
			 * m+ <- (* m+ B)
			 * m- <- (* m- B)
			 * k <- (- k 1)
			 */
			duk__bi_mul_small_copy(&nc_ctx->r, (duk_uint32_t) nc_ctx->B, &nc_ctx->t1);
			duk__bi_mul_small_copy(&nc_ctx->mp, (duk_uint32_t) nc_ctx->B, &nc_ctx->t1);
			if (nc_ctx->unequal_gaps) {
				DUK_DDD(DUK_DDDPRINT("m+ != m- -> need to update m- too"));
				duk__bi_mul_small_copy(&nc_ctx->mm, (duk_uint32_t) nc_ctx->B, &nc_ctx->t1);
			}
			k--;
		} else {
			break;
		}
	}

 skip_dec_k:

	if (!nc_ctx->unequal_gaps) {
		DUK_DDD(DUK_DDDPRINT("equal gaps, copy m- from m+"));
		duk__bi_copy(&nc_ctx->mm, &nc_ctx->mp);  /* mm <- mp */
	}
	nc_ctx->k = k;

	DUK_DDD(DUK_DDDPRINT("final k: %ld", (long) k));
	DUK__BI_PRINT("r(final)", &nc_ctx->r);
	DUK__BI_PRINT("s(final)", &nc_ctx->s);
	DUK__BI_PRINT("mp(final)", &nc_ctx->mp);
	DUK__BI_PRINT("mm(final)", &nc_ctx->mm);
}

DUK_LOCAL void duk__dragon4_generate(duk__numconv_stringify_ctx *nc_ctx) {
	duk_small_int_t tc1, tc2;    /* terminating conditions */
	duk_small_int_t d;           /* current digit */
	duk_small_int_t count = 0;   /* digit count */

	/*
	 *  Digit generation loop.
	 *
	 *  Different termination conditions:
	 *
	 *    1. Free format output.  Terminate when shortest accurate
	 *       representation found.
	 *
	 *    2. Fixed format output, with specific number of digits.
	 *       Ignore termination conditions, terminate when digits
	 *       generated.  Caller requests an extra digit and rounds.
	 *
	 *    3. Fixed format output, with a specific absolute cut-off
	 *       position (e.g. 10 digits after decimal point).  Note
	 *       that we always generate at least one digit, even if
	 *       the digit is below the cut-off point already.
	 */

	for (;;) {
		DUK_DDD(DUK_DDDPRINT("generate loop, count=%ld, k=%ld, B=%ld, low_ok=%ld, high_ok=%ld",
		                     (long) count, (long) nc_ctx->k, (long) nc_ctx->B,
		                     (long) nc_ctx->low_ok, (long) nc_ctx->high_ok));
		DUK__BI_PRINT("r", &nc_ctx->r);
		DUK__BI_PRINT("s", &nc_ctx->s);
		DUK__BI_PRINT("m+", &nc_ctx->mp);
		DUK__BI_PRINT("m-", &nc_ctx->mm);

		/* (quotient-remainder (* r B) s) using a dummy subtraction loop */
		duk__bi_mul_small(&nc_ctx->t1, &nc_ctx->r, (duk_uint32_t) nc_ctx->B);       /* t1 <- (* r B) */
		d = 0;
		for (;;) {
			if (duk__bi_compare(&nc_ctx->t1, &nc_ctx->s) < 0) {
				break;
			}
			duk__bi_sub_copy(&nc_ctx->t1, &nc_ctx->s, &nc_ctx->t2);  /* t1 <- t1 - s */
			d++;
		}
		duk__bi_copy(&nc_ctx->r, &nc_ctx->t1);  /* r <- (remainder (* r B) s) */
		                                        /* d <- (quotient (* r B) s)   (in range 0...B-1) */
		DUK_DDD(DUK_DDDPRINT("-> d(quot)=%ld", (long) d));
		DUK__BI_PRINT("r(rem)", &nc_ctx->r);

		duk__bi_mul_small_copy(&nc_ctx->mp, (duk_uint32_t) nc_ctx->B, &nc_ctx->t2); /* m+ <- (* m+ B) */
		duk__bi_mul_small_copy(&nc_ctx->mm, (duk_uint32_t) nc_ctx->B, &nc_ctx->t2); /* m- <- (* m- B) */
		DUK__BI_PRINT("mp(upd)", &nc_ctx->mp);
		DUK__BI_PRINT("mm(upd)", &nc_ctx->mm);

		/* Terminating conditions.  For fixed width output, we just ignore the
		 * terminating conditions (and pretend that tc1 == tc2 == false).  The
		 * the current shortcut for fixed-format output is to generate a few
		 * extra digits and use rounding (with carry) to finish the output.
		 */

		if (nc_ctx->is_fixed == 0) {
			/* free-form */
			tc1 = (duk__bi_compare(&nc_ctx->r, &nc_ctx->mm) <= (nc_ctx->low_ok ? 0 : -1));

			duk__bi_add(&nc_ctx->t1, &nc_ctx->r, &nc_ctx->mp);  /* t1 <- (+ r m+) */
			tc2 = (duk__bi_compare(&nc_ctx->t1, &nc_ctx->s) >= (nc_ctx->high_ok ? 0 : 1));

			DUK_DDD(DUK_DDDPRINT("tc1=%ld, tc2=%ld", (long) tc1, (long) tc2));
		} else {
			/* fixed-format */
			tc1 = 0;
			tc2 = 0;
		}

		/* Count is incremented before DUK__DRAGON4_OUTPUT_PREINC() call
		 * on purpose, which is taken into account by the macro.
		 */
		count++;

		if (tc1) {
			if (tc2) {
				/* tc1 = true, tc2 = true */
				duk__bi_mul_small(&nc_ctx->t1, &nc_ctx->r, 2);
				if (duk__bi_compare(&nc_ctx->t1, &nc_ctx->s) < 0) {  /* (< (* r 2) s) */
					DUK_DDD(DUK_DDDPRINT("tc1=true, tc2=true, 2r > s: output d --> %ld (k=%ld)",
					                     (long) d, (long) nc_ctx->k));
					DUK__DRAGON4_OUTPUT_PREINC(nc_ctx, count, d);
				} else {
					DUK_DDD(DUK_DDDPRINT("tc1=true, tc2=true, 2r <= s: output d+1 --> %ld (k=%ld)",
					                     (long) (d + 1), (long) nc_ctx->k));
					DUK__DRAGON4_OUTPUT_PREINC(nc_ctx, count, d + 1);
				}
				break;
			} else {
				/* tc1 = true, tc2 = false */
				DUK_DDD(DUK_DDDPRINT("tc1=true, tc2=false: output d --> %ld (k=%ld)",
				                     (long) d, (long) nc_ctx->k));
				DUK__DRAGON4_OUTPUT_PREINC(nc_ctx, count, d);
				break;
			}
		} else {
			if (tc2) {
				/* tc1 = false, tc2 = true */
				DUK_DDD(DUK_DDDPRINT("tc1=false, tc2=true: output d+1 --> %ld (k=%ld)",
				                     (long) (d + 1), (long) nc_ctx->k));
				DUK__DRAGON4_OUTPUT_PREINC(nc_ctx, count, d + 1);
				break;
			} else {
				/* tc1 = false, tc2 = false */
				DUK_DDD(DUK_DDDPRINT("tc1=false, tc2=false: output d --> %ld (k=%ld)",
				                     (long) d, (long) nc_ctx->k));
				DUK__DRAGON4_OUTPUT_PREINC(nc_ctx, count, d);

				/* r <- r    (updated above: r <- (remainder (* r B) s)
				 * s <- s
				 * m+ <- m+  (updated above: m+ <- (* m+ B)
				 * m- <- m-  (updated above: m- <- (* m- B)
				 * B, low_ok, high_ok are fixed
				 */

				/* fall through and continue for-loop */
			}
		}

		/* fixed-format termination conditions */
		if (nc_ctx->is_fixed) {
			if (nc_ctx->abs_pos) {
				int pos = nc_ctx->k - count + 1;  /* count is already incremented, take into account */
				DUK_DDD(DUK_DDDPRINT("fixed format, absolute: abs pos=%ld, k=%ld, count=%ld, req=%ld",
				                     (long) pos, (long) nc_ctx->k, (long) count, (long) nc_ctx->req_digits));
				if (pos <= nc_ctx->req_digits) {
					DUK_DDD(DUK_DDDPRINT("digit position reached req_digits, end generate loop"));
					break;
				}
			} else {
				DUK_DDD(DUK_DDDPRINT("fixed format, relative: k=%ld, count=%ld, req=%ld",
				                     (long) nc_ctx->k, (long) count, (long) nc_ctx->req_digits));
				if (count >= nc_ctx->req_digits) {
					DUK_DDD(DUK_DDDPRINT("digit count reached req_digits, end generate loop"));
					break;
				}
			}
		}
	}  /* for */

	nc_ctx->count = count;

	DUK_DDD(DUK_DDDPRINT("generate finished"));

#if defined(DUK_USE_DEBUG_LEVEL) && (DUK_USE_DEBUG_LEVEL >= 2)
	{
		duk_uint8_t buf[2048];
		duk_small_int_t i, t;
		duk_memzero(buf, sizeof(buf));
		for (i = 0; i < nc_ctx->count; i++) {
			t = nc_ctx->digits[i];
			if (t < 0 || t > 36) {
				buf[i] = (duk_uint8_t) '?';
			} else {
				buf[i] = (duk_uint8_t) DUK__DIGITCHAR(t);
			}
		}
		DUK_DDD(DUK_DDDPRINT("-> generated digits; k=%ld, digits='%s'",
		                     (long) nc_ctx->k, (const char *) buf));
	}
#endif
}

/* Round up digits to a given position.  If position is out-of-bounds,
 * does nothing.  If carry propagates over the first digit, a '1' is
 * prepended to digits and 'k' will be updated.  Return value indicates
 * whether carry propagated over the first digit.
 *
 * Note that nc_ctx->count is NOT updated based on the rounding position
 * (it is updated only if carry overflows over the first digit and an
 * extra digit is prepended).
 */
DUK_LOCAL duk_small_int_t duk__dragon4_fixed_format_round(duk__numconv_stringify_ctx *nc_ctx, duk_small_int_t round_idx) {
	duk_small_int_t t;
	duk_uint8_t *p;
	duk_uint8_t roundup_limit;
	duk_small_int_t ret = 0;

	/*
	 *  round_idx points to the digit which is considered for rounding; the
	 *  digit to its left is the final digit of the rounded value.  If round_idx
	 *  is zero, rounding will be performed; the result will either be an empty
	 *  rounded value or if carry happens a '1' digit is generated.
	 */

	if (round_idx >= nc_ctx->count) {
		DUK_DDD(DUK_DDDPRINT("round_idx out of bounds (%ld >= %ld (count)) -> no rounding",
		                     (long) round_idx, (long) nc_ctx->count));
		return 0;
	} else if (round_idx < 0) {
		DUK_DDD(DUK_DDDPRINT("round_idx out of bounds (%ld < 0) -> no rounding",
		                     (long) round_idx));
		return 0;
	}

	/*
	 *  Round-up limit.
	 *
	 *  For even values, divides evenly, e.g. 10 -> roundup_limit=5.
	 *
	 *  For odd values, rounds up, e.g. 3 -> roundup_limit=2.
	 *  If radix is 3, 0/3 -> down, 1/3 -> down, 2/3 -> up.
	 */
	roundup_limit = (duk_uint8_t) ((nc_ctx->B + 1) / 2);

	p = &nc_ctx->digits[round_idx];
	if (*p >= roundup_limit) {
		DUK_DDD(DUK_DDDPRINT("fixed-format rounding carry required"));
		/* carry */
		for (;;) {
			*p = 0;
			if (p == &nc_ctx->digits[0]) {
				DUK_DDD(DUK_DDDPRINT("carry propagated to first digit -> special case handling"));
				duk_memmove((void *) (&nc_ctx->digits[1]),
				            (const void *) (&nc_ctx->digits[0]),
				            (size_t) (sizeof(char) * (size_t) nc_ctx->count));
				nc_ctx->digits[0] = 1;  /* don't increase 'count' */
				nc_ctx->k++;  /* position of highest digit changed */
				nc_ctx->count++;  /* number of digits changed */
				ret = 1;
				break;
			}

			DUK_DDD(DUK_DDDPRINT("fixed-format rounding carry: B=%ld, roundup_limit=%ld, p=%p, digits=%p",
			                     (long) nc_ctx->B, (long) roundup_limit, (void *) p, (void *) nc_ctx->digits));
			p--;
			t = *p;
			DUK_DDD(DUK_DDDPRINT("digit before carry: %ld", (long) t));
			if (++t < nc_ctx->B) {
				DUK_DDD(DUK_DDDPRINT("rounding carry terminated"));
				*p = (duk_uint8_t) t;
				break;
			}

			DUK_DDD(DUK_DDDPRINT("wraps, carry to next digit"));
		}
	}

	return ret;
}

#define DUK__NO_EXP  (65536)  /* arbitrary marker, outside valid exp range */

DUK_LOCAL void duk__dragon4_convert_and_push(duk__numconv_stringify_ctx *nc_ctx,
                                             duk_hthread *thr,
                                             duk_small_int_t radix,
                                             duk_small_int_t digits,
                                             duk_small_uint_t flags,
                                             duk_small_int_t neg) {
	duk_small_int_t k;
	duk_small_int_t pos, pos_end;
	duk_small_int_t expt;
	duk_small_int_t dig;
	duk_uint8_t *q;
	duk_uint8_t *buf;

	/*
	 *  The string conversion here incorporates all the necessary ECMAScript
	 *  semantics without attempting to be generic.  nc_ctx->digits contains
	 *  nc_ctx->count digits (>= 1), with the topmost digit's 'position'
	 *  indicated by nc_ctx->k as follows:
	 *
	 *    digits="123" count=3 k=0   -->   0.123
	 *    digits="123" count=3 k=1   -->   1.23
	 *    digits="123" count=3 k=5   -->   12300
	 *    digits="123" count=3 k=-1  -->   0.0123
	 *
	 *  Note that the identifier names used for format selection are different
	 *  in Burger-Dybvig paper and ECMAScript specification (quite confusingly
	 *  so, because e.g. 'k' has a totally different meaning in each).  See
	 *  documentation for discussion.
	 *
	 *  ECMAScript doesn't specify any specific behavior for format selection
	 *  (e.g. when to use exponent notation) for non-base-10 numbers.
	 *
	 *  The bigint space in the context is reused for string output, as there
	 *  is more than enough space for that (>1kB at the moment), and we avoid
	 *  allocating even more stack.
	 */

	DUK_ASSERT(DUK__NUMCONV_CTX_BIGINTS_SIZE >= DUK__MAX_FORMATTED_LENGTH);
	DUK_ASSERT(nc_ctx->count >= 1);

	k = nc_ctx->k;
	buf = (duk_uint8_t *) &nc_ctx->f;  /* XXX: union would be more correct */
	q = buf;

	/* Exponent handling: if exponent format is used, record exponent value and
	 * fake k such that one leading digit is generated (e.g. digits=123 -> "1.23").
	 *
	 * toFixed() prevents exponent use; otherwise apply a set of criteria to
	 * match the other API calls (toString(), toPrecision, etc).
	 */

	expt = DUK__NO_EXP;
	if (!nc_ctx->abs_pos /* toFixed() */) {
		if ((flags & DUK_N2S_FLAG_FORCE_EXP) ||             /* exponential notation forced */
		    ((flags & DUK_N2S_FLAG_NO_ZERO_PAD) &&          /* fixed precision and zero padding would be required */
	             (k - digits >= 1)) ||                          /* (e.g. k=3, digits=2 -> "12X") */
		    ((k > 21 || k <= -6) && (radix == 10))) {       /* toString() conditions */
			DUK_DDD(DUK_DDDPRINT("use exponential notation: k=%ld -> expt=%ld",
			                     (long) k, (long) (k - 1)));
			expt = k - 1;  /* e.g. 12.3 -> digits="123" k=2 -> 1.23e1 */
			k = 1;  /* generate mantissa with a single leading whole number digit */
		}
	}

	if (neg) {
		*q++ = '-';
	}

	/* Start position (inclusive) and end position (exclusive) */
	pos = (k >= 1 ? k : 1);
	if (nc_ctx->is_fixed) {
		if (nc_ctx->abs_pos) {
			/* toFixed() */
			pos_end = -digits;
		} else {
			pos_end = k - digits;
		}
	} else {
		pos_end = k - nc_ctx->count;
	}
	if (pos_end > 0) {
		pos_end = 0;
	}

	DUK_DDD(DUK_DDDPRINT("expt=%ld, k=%ld, count=%ld, pos=%ld, pos_end=%ld, is_fixed=%ld, "
	                     "digits=%ld, abs_pos=%ld",
	                     (long) expt, (long) k, (long) nc_ctx->count, (long) pos, (long) pos_end,
	                     (long) nc_ctx->is_fixed, (long) digits, (long) nc_ctx->abs_pos));

	/* Digit generation */
	while (pos > pos_end) {
		DUK_DDD(DUK_DDDPRINT("digit generation: pos=%ld, pos_end=%ld",
		                     (long) pos, (long) pos_end));
		if (pos == 0) {
			*q++ = (duk_uint8_t) '.';
		}
		if (pos > k) {
			*q++ = (duk_uint8_t) '0';
		} else if (pos <= k - nc_ctx->count) {
			*q++ = (duk_uint8_t) '0';
		} else {
			dig = nc_ctx->digits[k - pos];
			DUK_ASSERT(dig >= 0 && dig < nc_ctx->B);
			*q++ = (duk_uint8_t) DUK__DIGITCHAR(dig);
		}

		pos--;
	}
	DUK_ASSERT(pos <= 1);

	/* Exponent */
	if (expt != DUK__NO_EXP) {
		/*
		 *  Exponent notation for non-base-10 numbers isn't specified in ECMAScript
		 *  specification, as it never explicitly turns up: non-decimal numbers can
		 *  only be formatted with Number.prototype.toString([radix]) and for that,
		 *  behavior is not explicitly specified.
		 *
		 *  Logical choices include formatting the exponent as decimal (e.g. binary
		 *  100000 as 1e+5) or in current radix (e.g. binary 100000 as 1e+101).
		 *  The Dragon4 algorithm (in the original paper) prints the exponent value
		 *  in the target radix B.  However, for radix values 15 and above, the
		 *  exponent separator 'e' is no longer easily parseable.  Consider, for
		 *  instance, the number "1.faecee+1c".
		 */

		duk_size_t len;
		char expt_sign;

		*q++ = 'e';
		if (expt >= 0) {
			expt_sign = '+';
		} else {
			expt_sign = '-';
			expt = -expt;
		}
		*q++ = (duk_uint8_t) expt_sign;
		len = duk__dragon4_format_uint32(q, (duk_uint32_t) expt, radix);
		q += len;
	}

	duk_push_lstring(thr, (const char *) buf, (size_t) (q - buf));
}

/*
 *  Conversion helpers
 */

DUK_LOCAL void duk__dragon4_double_to_ctx(duk__numconv_stringify_ctx *nc_ctx, duk_double_t x) {
	duk_double_union u;
	duk_uint32_t tmp;
	duk_small_int_t expt;

	/*
	 *    seeeeeee eeeeffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
	 *       A        B        C        D        E        F        G        H
	 *
	 *    s       sign bit
	 *    eee...  exponent field
	 *    fff...  fraction
	 *
	 *    ieee value = 1.ffff... * 2^(e - 1023)  (normal)
	 *               = 0.ffff... * 2^(-1022)     (denormal)
	 *
	 *    algorithm v = f * b^e
	 */

	DUK_DBLUNION_SET_DOUBLE(&u, x);

	nc_ctx->f.n = 2;

	tmp = DUK_DBLUNION_GET_LOW32(&u);
	nc_ctx->f.v[0] = tmp;
	tmp = DUK_DBLUNION_GET_HIGH32(&u);
	nc_ctx->f.v[1] = tmp & 0x000fffffUL;
	expt = (duk_small_int_t) ((tmp >> 20) & 0x07ffUL);

	if (expt == 0) {
		/* denormal */
		expt = DUK__IEEE_DOUBLE_EXP_MIN - 52;
		duk__bi_normalize(&nc_ctx->f);
	} else {
		/* normal: implicit leading 1-bit */
		nc_ctx->f.v[1] |= 0x00100000UL;
		expt = expt - DUK__IEEE_DOUBLE_EXP_BIAS - 52;
		DUK_ASSERT(duk__bi_is_valid(&nc_ctx->f));  /* true, because v[1] has at least one bit set */
	}

	DUK_ASSERT(duk__bi_is_valid(&nc_ctx->f));

	nc_ctx->e = expt;
}

DUK_LOCAL void duk__dragon4_ctx_to_double(duk__numconv_stringify_ctx *nc_ctx, duk_double_t *x) {
	duk_double_union u;
	duk_small_int_t expt;
	duk_small_int_t i;
	duk_small_int_t bitstart;
	duk_small_int_t bitround;
	duk_small_int_t bitidx;
	duk_small_int_t skip_round;
	duk_uint32_t t, v;

	DUK_ASSERT(nc_ctx->count == 53 + 1);

	/* Sometimes this assert is not true right now; it will be true after
	 * rounding.  See: test-bug-numconv-mantissa-assert.js.
	 */
	DUK_ASSERT_DISABLE(nc_ctx->digits[0] == 1);  /* zero handled by caller */

	/* Should not be required because the code below always sets both high
	 * and low parts, but at least gcc-4.4.5 fails to deduce this correctly
	 * (perhaps because the low part is set (seemingly) conditionally in a
	 * loop), so this is here to avoid the bogus warning.
	 */
	duk_memzero((void *) &u, sizeof(u));

	/*
	 *  Figure out how generated digits match up with the mantissa,
	 *  and then perform rounding.  If mantissa overflows, need to
	 *  recompute the exponent (it is bumped and may overflow to
	 *  infinity).
	 *
	 *  For normal numbers the leading '1' is hidden and ignored,
	 *  and the last bit is used for rounding:
	 *
	 *                          rounding pt
	 *       <--------52------->|
	 *     1 x x x x ... x x x x|y  ==>  x x x x ... x x x x
	 *
	 *  For denormals, the leading '1' is included in the number,
	 *  and the rounding point is different:
	 *
	 *                      rounding pt
	 *     <--52 or less--->|
	 *     1 x x x x ... x x|x x y  ==>  0 0 ... 1 x x ... x x
	 *
	 *  The largest denormals will have a mantissa beginning with
	 *  a '1' (the explicit leading bit); smaller denormals will
	 *  have leading zero bits.
	 *
	 *  If the exponent would become too high, the result becomes
	 *  Infinity.  If the exponent is so small that the entire
	 *  mantissa becomes zero, the result becomes zero.
	 *
	 *  Note: the Dragon4 'k' is off-by-one with respect to the IEEE
	 *  exponent.  For instance, k==0 indicates that the leading '1'
	 *  digit is at the first binary fraction position (0.1xxx...);
	 *  the corresponding IEEE exponent would be -1.
	 */

	skip_round = 0;

 recheck_exp:

	expt = nc_ctx->k - 1;   /* IEEE exp without bias */
	if (expt > 1023) {
		/* Infinity */
		bitstart = -255;  /* needed for inf: causes mantissa to become zero,
		                   * and rounding to be skipped.
		                   */
		expt = 2047;
	} else if (expt >= -1022) {
		/* normal */
		bitstart = 1;  /* skip leading digit */
		expt += DUK__IEEE_DOUBLE_EXP_BIAS;
		DUK_ASSERT(expt >= 1 && expt <= 2046);
	} else {
		/* denormal or zero */
		bitstart = 1023 + expt;  /* expt==-1023 -> bitstart=0 (leading 1);
		                          * expt==-1024 -> bitstart=-1 (one left of leading 1), etc
		                          */
		expt = 0;
	}
	bitround = bitstart + 52;

	DUK_DDD(DUK_DDDPRINT("ieee expt=%ld, bitstart=%ld, bitround=%ld",
	                     (long) expt, (long) bitstart, (long) bitround));

	if (!skip_round) {
		if (duk__dragon4_fixed_format_round(nc_ctx, bitround)) {
			/* Corner case: see test-numconv-parse-mant-carry.js.  We could
			 * just bump the exponent and update bitstart, but it's more robust
			 * to recompute (but avoid rounding twice).
			 */
			DUK_DDD(DUK_DDDPRINT("rounding caused exponent to be bumped, recheck exponent"));
			skip_round = 1;
			goto recheck_exp;
		}
	}

	/*
	 *  Create mantissa
	 */

	t = 0;
	for (i = 0; i < 52; i++) {
		bitidx = bitstart + 52 - 1 - i;
		if (bitidx >= nc_ctx->count) {
			v = 0;
		} else if (bitidx < 0) {
			v = 0;
		} else {
			v = nc_ctx->digits[bitidx];
		}
		DUK_ASSERT(v == 0 || v == 1);
		t += v << (i % 32);
		if (i == 31) {
			/* low 32 bits is complete */
			DUK_DBLUNION_SET_LOW32(&u, t);
			t = 0;
		}
	}
	/* t has high mantissa */

	DUK_DDD(DUK_DDDPRINT("mantissa is complete: %08lx %08lx",
	                     (unsigned long) t,
	                     (unsigned long) DUK_DBLUNION_GET_LOW32(&u)));

	DUK_ASSERT(expt >= 0 && expt <= 0x7ffL);
	t += ((duk_uint32_t) expt) << 20;
#if 0  /* caller handles sign change */
	if (negative) {
		t |= 0x80000000U;
	}
#endif
	DUK_DBLUNION_SET_HIGH32(&u, t);

	DUK_DDD(DUK_DDDPRINT("number is complete: %08lx %08lx",
	                     (unsigned long) DUK_DBLUNION_GET_HIGH32(&u),
	                     (unsigned long) DUK_DBLUNION_GET_LOW32(&u)));

	*x = DUK_DBLUNION_GET_DOUBLE(&u);
}

/*
 *  Exposed number-to-string API
 *
 *  Input: [ number ]
 *  Output: [ string ]
 */

DUK_LOCAL DUK_NOINLINE void duk__numconv_stringify_raw(duk_hthread *thr, duk_small_int_t radix, duk_small_int_t digits, duk_small_uint_t flags) {
	duk_double_t x;
	duk_small_int_t c;
	duk_small_int_t neg;
	duk_uint32_t uval;
	duk__numconv_stringify_ctx nc_ctx_alloc;  /* large context; around 2kB now */
	duk__numconv_stringify_ctx *nc_ctx = &nc_ctx_alloc;

	x = (duk_double_t) duk_require_number(thr, -1);
	duk_pop(thr);

	/*
	 *  Handle special cases (NaN, infinity, zero).
	 */

	c = (duk_small_int_t) DUK_FPCLASSIFY(x);
	if (DUK_SIGNBIT((double) x)) {
		x = -x;
		neg = 1;
	} else {
		neg = 0;
	}

	/* NaN sign bit is platform specific with unpacked, un-normalized NaNs */
	DUK_ASSERT(c == DUK_FP_NAN || DUK_SIGNBIT((double) x) == 0);

	if (c == DUK_FP_NAN) {
		duk_push_hstring_stridx(thr, DUK_STRIDX_NAN);
		return;
	} else if (c == DUK_FP_INFINITE) {
		if (neg) {
			/* -Infinity */
			duk_push_hstring_stridx(thr, DUK_STRIDX_MINUS_INFINITY);
		} else {
			/* Infinity */
			duk_push_hstring_stridx(thr, DUK_STRIDX_INFINITY);
		}
		return;
	} else if (c == DUK_FP_ZERO) {
		/* We can't shortcut zero here if it goes through special formatting
		 * (such as forced exponential notation).
		 */
		;
	}

	/*
	 *  Handle integers in 32-bit range (that is, [-(2**32-1),2**32-1])
	 *  specially, as they're very likely for embedded programs.  This
	 *  is now done for all radix values.  We must be careful not to use
	 *  the fast path when special formatting (e.g. forced exponential)
	 *  is in force.
	 *
	 *  XXX: could save space by supporting radix 10 only and using
	 *  sprintf "%lu" for the fast path and for exponent formatting.
	 */

	uval = duk_double_to_uint32_t(x);
	if (duk_double_equals((double) uval, x) &&  /* integer number in range */
	    flags == 0) {                           /* no special formatting */
		/* use bigint area as a temp */
		duk_uint8_t *buf = (duk_uint8_t *) (&nc_ctx->f);
		duk_uint8_t *p = buf;

		DUK_ASSERT(DUK__NUMCONV_CTX_BIGINTS_SIZE >= 32 + 1);  /* max size: radix=2 + sign */
		if (neg && uval != 0) {
			/* no negative sign for zero */
			*p++ = (duk_uint8_t) '-';
		}
		p += duk__dragon4_format_uint32(p, uval, radix);
		duk_push_lstring(thr, (const char *) buf, (duk_size_t) (p - buf));
		return;
	}

	/*
	 *  Dragon4 setup.
	 *
	 *  Convert double from IEEE representation for conversion;
	 *  normal finite values have an implicit leading 1-bit.  The
	 *  slow path algorithm doesn't handle zero, so zero is special
	 *  cased here but still creates a valid nc_ctx, and goes
	 *  through normal formatting in case special formatting has
	 *  been requested (e.g. forced exponential format: 0 -> "0e+0").
	 */

	/* Would be nice to bulk clear the allocation, but the context
	 * is 1-2 kilobytes and nothing should rely on it being zeroed.
	 */
#if 0
	duk_memzero((void *) nc_ctx, sizeof(*nc_ctx));  /* slow init, do only for slow path cases */
#endif

	nc_ctx->is_s2n = 0;
	nc_ctx->b = 2;
	nc_ctx->B = radix;
	nc_ctx->abs_pos = 0;
	if (flags & DUK_N2S_FLAG_FIXED_FORMAT) {
		nc_ctx->is_fixed = 1;
		if (flags & DUK_N2S_FLAG_FRACTION_DIGITS) {
			/* absolute req_digits; e.g. digits = 1 -> last digit is 0,
			 * but add an extra digit for rounding.
			 */
			nc_ctx->abs_pos = 1;
			nc_ctx->req_digits = (-digits + 1) - 1;
		} else {
			nc_ctx->req_digits = digits + 1;
		}
	} else {
		nc_ctx->is_fixed = 0;
		nc_ctx->req_digits = 0;
	}

	if (c == DUK_FP_ZERO) {
		/* Zero special case: fake requested number of zero digits; ensure
		 * no sign bit is printed.  Relative and absolute fixed format
		 * require separate handling.
		 */
		duk_small_int_t count;
		if (nc_ctx->is_fixed) {
			if (nc_ctx->abs_pos) {
				count = digits + 2;  /* lead zero + 'digits' fractions + 1 for rounding */
			} else {
				count = digits + 1;  /* + 1 for rounding */
			}
		} else {
			count = 1;
		}
		DUK_DDD(DUK_DDDPRINT("count=%ld", (long) count));
		DUK_ASSERT(count >= 1);
		duk_memzero((void *) nc_ctx->digits, (size_t) count);
		nc_ctx->count = count;
		nc_ctx->k = 1;  /* 0.000... */
		neg = 0;
		goto zero_skip;
	}

	duk__dragon4_double_to_ctx(nc_ctx, x);   /* -> sets 'f' and 'e' */
	DUK__BI_PRINT("f", &nc_ctx->f);
	DUK_DDD(DUK_DDDPRINT("e=%ld", (long) nc_ctx->e));

	/*
	 *  Dragon4 slow path digit generation.
	 */

	duk__dragon4_prepare(nc_ctx);  /* setup many variables in nc_ctx */

	DUK_DDD(DUK_DDDPRINT("after prepare:"));
	DUK__BI_PRINT("r", &nc_ctx->r);
	DUK__BI_PRINT("s", &nc_ctx->s);
	DUK__BI_PRINT("mp", &nc_ctx->mp);
	DUK__BI_PRINT("mm", &nc_ctx->mm);

	duk__dragon4_scale(nc_ctx);

	DUK_DDD(DUK_DDDPRINT("after scale; k=%ld", (long) nc_ctx->k));
	DUK__BI_PRINT("r", &nc_ctx->r);
	DUK__BI_PRINT("s", &nc_ctx->s);
	DUK__BI_PRINT("mp", &nc_ctx->mp);
	DUK__BI_PRINT("mm", &nc_ctx->mm);

	duk__dragon4_generate(nc_ctx);

	/*
	 *  Convert and push final string.
	 */

 zero_skip:

	if (flags & DUK_N2S_FLAG_FIXED_FORMAT) {
		/* Perform fixed-format rounding. */
		duk_small_int_t roundpos;
		if (flags & DUK_N2S_FLAG_FRACTION_DIGITS) {
			/* 'roundpos' is relative to nc_ctx->k and increases to the right
			 * (opposite of how 'k' changes).
			 */
			roundpos = -digits;  /* absolute position for digit considered for rounding */
			roundpos = nc_ctx->k - roundpos;
		} else {
			roundpos = digits;
		}
		DUK_DDD(DUK_DDDPRINT("rounding: k=%ld, count=%ld, digits=%ld, roundpos=%ld",
		                     (long) nc_ctx->k, (long) nc_ctx->count, (long) digits, (long) roundpos));
		(void) duk__dragon4_fixed_format_round(nc_ctx, roundpos);

		/* Note: 'count' is currently not adjusted by rounding (i.e. the
		 * digits are not "chopped off".  That shouldn't matter because
		 * the digit position (absolute or relative) is passed on to the
		 * convert-and-push function.
		 */
	}

	duk__dragon4_convert_and_push(nc_ctx, thr, radix, digits, flags, neg);
}

DUK_INTERNAL void duk_numconv_stringify(duk_hthread *thr, duk_small_int_t radix, duk_small_int_t digits, duk_small_uint_t flags) {
	duk_native_stack_check(thr);
	duk__numconv_stringify_raw(thr, radix, digits, flags);
}

/*
 *  Exposed string-to-number API
 *
 *  Input: [ string ]
 *  Output: [ number ]
 *
 *  If number parsing fails, a NaN is pushed as the result.  If number parsing
 *  fails due to an internal error, an InternalError is thrown.
 */

DUK_LOCAL DUK_NOINLINE void duk__numconv_parse_raw(duk_hthread *thr, duk_small_int_t radix, duk_small_uint_t flags) {
	duk__numconv_stringify_ctx nc_ctx_alloc;  /* large context; around 2kB now */
	duk__numconv_stringify_ctx *nc_ctx = &nc_ctx_alloc;
	duk_double_t res;
	duk_hstring *h_str;
	duk_int_t expt;
	duk_bool_t expt_neg;
	duk_small_int_t expt_adj;
	duk_small_int_t neg;
	duk_small_int_t dig;
	duk_small_int_t dig_whole;
	duk_small_int_t dig_lzero;
	duk_small_int_t dig_frac;
	duk_small_int_t dig_expt;
	duk_small_int_t dig_prec;
	const duk__exp_limits *explim;
	const duk_uint8_t *p;
	duk_small_int_t ch;

	DUK_DDD(DUK_DDDPRINT("parse number: %!T, radix=%ld, flags=0x%08lx",
	                     (duk_tval *) duk_get_tval(thr, -1),
	                     (long) radix, (unsigned long) flags));

	DUK_ASSERT(radix >= 2 && radix <= 36);
	DUK_ASSERT(radix - 2 < (duk_small_int_t) sizeof(duk__str2num_digits_for_radix));

	/*
	 *  Preliminaries: trim, sign, Infinity check
	 *
	 *  We rely on the interned string having a NUL terminator, which will
	 *  cause a parse failure wherever it is encountered.  As a result, we
	 *  don't need separate pointer checks.
	 *
	 *  There is no special parsing for 'NaN' in the specification although
	 *  'Infinity' (with an optional sign) is allowed in some contexts.
	 *  Some contexts allow plus/minus sign, while others only allow the
	 *  minus sign (like JSON.parse()).
	 *
	 *  Automatic hex number detection (leading '0x' or '0X') and octal
	 *  number detection (leading '0' followed by at least one octal digit)
	 *  is done here too.
	 *
	 *  Symbols are not explicitly rejected here (that's up to the caller).
	 *  If a symbol were passed here, it should ultimately safely fail
	 *  parsing due to a syntax error.
	 */

	if (flags & DUK_S2N_FLAG_TRIM_WHITE) {
		/* Leading / trailing whitespace is sometimes accepted and
		 * sometimes not.  After white space trimming, all valid input
		 * characters are pure ASCII.
		 */
		duk_trim(thr, -1);
	}
	h_str = duk_require_hstring(thr, -1);
	DUK_ASSERT(h_str != NULL);
	p = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_str);

	neg = 0;
	ch = *p;
	if (ch == (duk_small_int_t) '+') {
		if ((flags & DUK_S2N_FLAG_ALLOW_PLUS) == 0) {
			DUK_DDD(DUK_DDDPRINT("parse failed: leading plus sign not allowed"));
			goto parse_fail;
		}
		p++;
	} else if (ch == (duk_small_int_t) '-') {
		if ((flags & DUK_S2N_FLAG_ALLOW_MINUS) == 0) {
			DUK_DDD(DUK_DDDPRINT("parse failed: leading minus sign not allowed"));
			goto parse_fail;
		}
		p++;
		neg = 1;
	}

	if ((flags & DUK_S2N_FLAG_ALLOW_INF) && DUK_STRNCMP((const char *) p, "Infinity", 8) == 0) {
		/* Don't check for Infinity unless the context allows it.
		 * 'Infinity' is a valid integer literal in e.g. base-36:
		 *
		 *   parseInt('Infinity', 36)
		 *   1461559270678
		 */

		if ((flags & DUK_S2N_FLAG_ALLOW_GARBAGE) == 0 && p[8] != DUK_ASC_NUL) {
			DUK_DDD(DUK_DDDPRINT("parse failed: trailing garbage after matching 'Infinity' not allowed"));
			goto parse_fail;
		} else {
			res = DUK_DOUBLE_INFINITY;
			goto negcheck_and_ret;
		}
	}
	ch = *p;
	if (ch == (duk_small_int_t) '0') {
		duk_small_int_t detect_radix = 0;
		ch = DUK_LOWERCASE_CHAR_ASCII(p[1]);  /* 'x' or 'X' -> 'x' */
		if ((flags & DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT) && ch == DUK_ASC_LC_X) {
			DUK_DDD(DUK_DDDPRINT("detected 0x/0X hex prefix, changing radix and preventing fractions and exponent"));
			detect_radix = 16;
#if 0
		} else if ((flags & DUK_S2N_FLAG_ALLOW_AUTO_LEGACY_OCT_INT) &&
		           (ch >= (duk_small_int_t) '0' && ch <= (duk_small_int_t) '9')) {
			DUK_DDD(DUK_DDDPRINT("detected 0n oct prefix, changing radix and preventing fractions and exponent"));
			detect_radix = 8;

			/* NOTE: if this legacy octal case is added back, it has
			 * different flags and 'p' advance so this needs to be
			 * reworked.
			 */
			flags |= DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO;  /* interpret e.g. '09' as '0', not NaN */
			p += 1;
#endif
		} else if ((flags & DUK_S2N_FLAG_ALLOW_AUTO_OCT_INT) && ch == DUK_ASC_LC_O) {
			DUK_DDD(DUK_DDDPRINT("detected 0o oct prefix, changing radix and preventing fractions and exponent"));
			detect_radix = 8;
		} else if ((flags & DUK_S2N_FLAG_ALLOW_AUTO_BIN_INT) && ch == DUK_ASC_LC_B) {
			DUK_DDD(DUK_DDDPRINT("detected 0b bin prefix, changing radix and preventing fractions and exponent"));
			detect_radix = 2;
		}
		if (detect_radix > 0) {
			radix = detect_radix;
			/* Clear empty as zero flag: interpret e.g. '0x' and '0xg' as a NaN (= parse error) */
			flags &= ~(DUK_S2N_FLAG_ALLOW_EXP | DUK_S2N_FLAG_ALLOW_EMPTY_FRAC |
			           DUK_S2N_FLAG_ALLOW_FRAC | DUK_S2N_FLAG_ALLOW_NAKED_FRAC |
			           DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO);
			flags |= DUK_S2N_FLAG_ALLOW_LEADING_ZERO;  /* allow e.g. '0x0009' and '0b00010001' */
			p += 2;
		}
	}

	/*
	 *  Scan number and setup for Dragon4.
	 *
	 *  The fast path case is detected during setup: an integer which
	 *  can be converted without rounding, no net exponent.  The fast
	 *  path could be implemented as a separate scan, but may not really
	 *  be worth it: the multiplications for building 'f' are not
	 *  expensive when 'f' is small.
	 *
	 *  The significand ('f') must contain enough bits of (apparent)
	 *  accuracy, so that Dragon4 will generate enough binary output digits.
	 *  For decimal numbers, this means generating a 20-digit significand,
	 *  which should yield enough practical accuracy to parse IEEE doubles.
	 *  In fact, the ECMAScript specification explicitly allows an
	 *  implementation to treat digits beyond 20 as zeroes (and even
	 *  to round the 20th digit upwards).  For non-decimal numbers, the
	 *  appropriate number of digits has been precomputed for comparable
	 *  accuracy.
	 *
	 *  Digit counts:
	 *
	 *    [ dig_lzero ]
	 *      |
	 *     .+-..---[ dig_prec ]----.
	 *     |  ||                   |
	 *     0000123.456789012345678901234567890e+123456
	 *     |     | |                         |  |    |
	 *     `--+--' `------[ dig_frac ]-------'  `-+--'
	 *        |                                   |
	 *    [ dig_whole ]                       [ dig_expt ]
	 *
	 *    dig_frac and dig_expt are -1 if not present
	 *    dig_lzero is only computed for whole number part
	 *
	 *  Parsing state
	 *
	 *     Parsing whole part      dig_frac < 0 AND dig_expt < 0
	 *     Parsing fraction part   dig_frac >= 0 AND dig_expt < 0
	 *     Parsing exponent part   dig_expt >= 0   (dig_frac may be < 0 or >= 0)
	 *
	 *  Note: in case we hit an implementation limit (like exponent range),
	 *  we should throw an error, NOT return NaN or Infinity.  Even with
	 *  very large exponent (or significand) values the final result may be
	 *  finite, so NaN/Infinity would be incorrect.
	 */

	duk__bi_set_small(&nc_ctx->f, 0);
	dig_prec = 0;
	dig_lzero = 0;
	dig_whole = 0;
	dig_frac = -1;
	dig_expt = -1;
	expt = 0;
	expt_adj = 0;  /* essentially tracks digit position of lowest 'f' digit */
	expt_neg = 0;
	for (;;) {
		ch = *p++;

		DUK_DDD(DUK_DDDPRINT("parse digits: p=%p, ch='%c' (%ld), expt=%ld, expt_adj=%ld, "
		                     "dig_whole=%ld, dig_frac=%ld, dig_expt=%ld, dig_lzero=%ld, dig_prec=%ld",
		                     (const void *) p, (int) ((ch >= 0x20 && ch <= 0x7e) ? ch : '?'), (long) ch,
		                     (long) expt, (long) expt_adj, (long) dig_whole, (long) dig_frac,
		                     (long) dig_expt, (long) dig_lzero, (long) dig_prec));
		DUK__BI_PRINT("f", &nc_ctx->f);

		/* Most common cases first. */
		if (ch >= (duk_small_int_t) '0' && ch <= (duk_small_int_t) '9') {
			dig = (duk_small_int_t) ch - '0' + 0;
		} else if (ch == (duk_small_int_t) '.') {
			/* A leading digit is not required in some cases, e.g. accept ".123".
			 * In other cases (JSON.parse()) a leading digit is required.  This
			 * is checked for after the loop.
			 */
			if (dig_frac >= 0 || dig_expt >= 0) {
				if (flags & DUK_S2N_FLAG_ALLOW_GARBAGE) {
					DUK_DDD(DUK_DDDPRINT("garbage termination (invalid period)"));
					break;
				} else {
					DUK_DDD(DUK_DDDPRINT("parse failed: period not allowed"));
					goto parse_fail;
				}
			}

			if ((flags & DUK_S2N_FLAG_ALLOW_FRAC) == 0) {
				/* Some contexts don't allow fractions at all; this can't be a
				 * post-check because the state ('f' and expt) would be incorrect.
				 */
				if (flags & DUK_S2N_FLAG_ALLOW_GARBAGE) {
					DUK_DDD(DUK_DDDPRINT("garbage termination (invalid first period)"));
					break;
				} else {
					DUK_DDD(DUK_DDDPRINT("parse failed: fraction part not allowed"));
				}
			}

			DUK_DDD(DUK_DDDPRINT("start fraction part"));
			dig_frac = 0;
			continue;
		} else if (ch == (duk_small_int_t) 0) {
			DUK_DDD(DUK_DDDPRINT("NUL termination"));
			break;
		} else if ((flags & DUK_S2N_FLAG_ALLOW_EXP) &&
		           dig_expt < 0 && (ch == (duk_small_int_t) 'e' || ch == (duk_small_int_t) 'E')) {
			/* Note: we don't parse back exponent notation for anything else
			 * than radix 10, so this is not an ambiguous check (e.g. hex
			 * exponent values may have 'e' either as a significand digit
			 * or as an exponent separator).
			 *
			 * If the exponent separator occurs twice, 'e' will be interpreted
			 * as a digit (= 14) and will be rejected as an invalid decimal
			 * digit.
			 */

			DUK_DDD(DUK_DDDPRINT("start exponent part"));

			/* Exponent without a sign or with a +/- sign is accepted
			 * by all call sites (even JSON.parse()).
			 */
			ch = *p;
			if (ch == (duk_small_int_t) '-') {
				expt_neg = 1;
				p++;
			} else if (ch == (duk_small_int_t) '+') {
				p++;
			}
			dig_expt = 0;
			continue;
		} else if (ch >= (duk_small_int_t) 'a' && ch <= (duk_small_int_t) 'z') {
			dig = (duk_small_int_t) (ch - (duk_small_int_t) 'a' + 0x0a);
		} else if (ch >= (duk_small_int_t) 'A' && ch <= (duk_small_int_t) 'Z') {
			dig = (duk_small_int_t) (ch - (duk_small_int_t) 'A' + 0x0a);
		} else {
			dig = 255;  /* triggers garbage digit check below */
		}
		DUK_ASSERT((dig >= 0 && dig <= 35) || dig == 255);

		if (dig >= radix) {
			if (flags & DUK_S2N_FLAG_ALLOW_GARBAGE) {
				DUK_DDD(DUK_DDDPRINT("garbage termination"));
				break;
			} else {
				DUK_DDD(DUK_DDDPRINT("parse failed: trailing garbage or invalid digit"));
				goto parse_fail;
			}
		}

		if (dig_expt < 0) {
			/* whole or fraction digit */

			if (dig_prec < duk__str2num_digits_for_radix[radix - 2]) {
				/* significant from precision perspective */

				duk_small_int_t f_zero = duk__bi_is_zero(&nc_ctx->f);
				if (f_zero && dig == 0) {
					/* Leading zero is not counted towards precision digits; not
					 * in the integer part, nor in the fraction part.
					 */
					if (dig_frac < 0) {
						dig_lzero++;
					}
				} else {
					/* XXX: join these ops (multiply-accumulate), but only if
					 * code footprint decreases.
					 */
					duk__bi_mul_small(&nc_ctx->t1, &nc_ctx->f, (duk_uint32_t) radix);
					duk__bi_add_small(&nc_ctx->f, &nc_ctx->t1, (duk_uint32_t) dig);
					dig_prec++;
				}
			} else {
				/* Ignore digits beyond a radix-specific limit, but note them
				 * in expt_adj.
				 */
				expt_adj++;
			}

			if (dig_frac >= 0) {
				dig_frac++;
				expt_adj--;
			} else {
				dig_whole++;
			}
		} else {
			/* exponent digit */

			DUK_ASSERT(radix == 10);
			expt = expt * radix + dig;
			if (expt > DUK_S2N_MAX_EXPONENT) {
				/* Impose a reasonable exponent limit, so that exp
				 * doesn't need to get tracked using a bigint.
				 */
				DUK_DDD(DUK_DDDPRINT("parse failed: exponent too large"));
				goto parse_explimit_error;
			}
			dig_expt++;
		}
	}

	/* Leading zero. */

	if (dig_lzero > 0 && dig_whole > 1) {
		if ((flags & DUK_S2N_FLAG_ALLOW_LEADING_ZERO) == 0) {
			DUK_DDD(DUK_DDDPRINT("parse failed: leading zeroes not allowed in integer part"));
			goto parse_fail;
		}
	}

	/* Validity checks for various fraction formats ("0.1", ".1", "1.", "."). */

	if (dig_whole == 0) {
		if (dig_frac == 0) {
			/* "." is not accepted in any format */
			DUK_DDD(DUK_DDDPRINT("parse failed: plain period without leading or trailing digits"));
			goto parse_fail;
		} else if (dig_frac > 0) {
			/* ".123" */
			if ((flags & DUK_S2N_FLAG_ALLOW_NAKED_FRAC) == 0) {
				DUK_DDD(DUK_DDDPRINT("parse failed: fraction part not allowed without "
				                     "leading integer digit(s)"));
				goto parse_fail;
			}
		} else {
			/* Empty ("") is allowed in some formats (e.g. Number(''), as zero,
			 * but it must not have a leading +/- sign (GH-2019).  Note that
			 * for Number(), h_str is already trimmed so we can check for zero
			 * length and still get Number('  +  ') == NaN.
			 */
			if ((flags & DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO) == 0) {
				DUK_DDD(DUK_DDDPRINT("parse failed: empty string not allowed (as zero)"));
				goto parse_fail;
			} else if (DUK_HSTRING_GET_BYTELEN(h_str) != 0) {
				DUK_DDD(DUK_DDDPRINT("parse failed: no digits, but not empty (had a +/- sign)"));
				goto parse_fail;
			}
		}
	} else {
		if (dig_frac == 0) {
			/* "123." is allowed in some formats */
			if ((flags & DUK_S2N_FLAG_ALLOW_EMPTY_FRAC) == 0) {
				DUK_DDD(DUK_DDDPRINT("parse failed: empty fractions"));
				goto parse_fail;
			}
		} else if (dig_frac > 0) {
			/* "123.456" */
			;
		} else {
			/* "123" */
			;
		}
	}

	/* Exponent without digits (e.g. "1e" or "1e+").  If trailing garbage is
	 * allowed, ignore exponent part as garbage (= parse as "1", i.e. exp 0).
	 */

	if (dig_expt == 0) {
		if ((flags & DUK_S2N_FLAG_ALLOW_GARBAGE) == 0) {
			DUK_DDD(DUK_DDDPRINT("parse failed: empty exponent"));
			goto parse_fail;
		}
		DUK_ASSERT(expt == 0);
	}

	if (expt_neg) {
		expt = -expt;
	}
	DUK_DDD(DUK_DDDPRINT("expt=%ld, expt_adj=%ld, net exponent -> %ld",
	                     (long) expt, (long) expt_adj, (long) (expt + expt_adj)));
	expt += expt_adj;

	/* Fast path check. */

	if (nc_ctx->f.n <= 1 &&   /* 32-bit value */
	    expt == 0    /* no net exponent */) {
		/* Fast path is triggered for no exponent and also for balanced exponent
		 * and fraction parts, e.g. for "1.23e2" == "123".  Remember to respect
		 * zero sign.
		 */

		/* XXX: could accept numbers larger than 32 bits, e.g. up to 53 bits? */
		DUK_DDD(DUK_DDDPRINT("fast path number parse"));
		if (nc_ctx->f.n == 1) {
			res = (double) nc_ctx->f.v[0];
		} else {
			res = 0.0;
		}
		goto negcheck_and_ret;
	}

	/* Significand ('f') padding. */

	while (dig_prec < duk__str2num_digits_for_radix[radix - 2]) {
		/* Pad significand with "virtual" zero digits so that Dragon4 will
		 * have enough (apparent) precision to work with.
		 */
		DUK_DDD(DUK_DDDPRINT("dig_prec=%ld, pad significand with zero", (long) dig_prec));
		duk__bi_mul_small_copy(&nc_ctx->f, (duk_uint32_t) radix, &nc_ctx->t1);
		DUK__BI_PRINT("f", &nc_ctx->f);
		expt--;
		dig_prec++;
	}

	DUK_DDD(DUK_DDDPRINT("final exponent: %ld", (long) expt));

	/* Detect zero special case. */

	if (nc_ctx->f.n == 0) {
		/* This may happen even after the fast path check, if exponent is
		 * not balanced (e.g. "0e1").  Remember to respect zero sign.
		 */
		DUK_DDD(DUK_DDDPRINT("significand is zero"));
		res = 0.0;
		goto negcheck_and_ret;
	}


	/* Quick reject of too large or too small exponents.  This check
	 * would be incorrect for zero (e.g. "0e1000" is zero, not Infinity)
	 * so zero check must be above.
	 */

	explim = &duk__str2num_exp_limits[radix - 2];
	if (expt > explim->upper) {
		DUK_DDD(DUK_DDDPRINT("exponent too large -> infinite"));
		res = (duk_double_t) DUK_DOUBLE_INFINITY;
		goto negcheck_and_ret;
	} else if (expt < explim->lower) {
		DUK_DDD(DUK_DDDPRINT("exponent too small -> zero"));
		res = (duk_double_t) 0.0;
		goto negcheck_and_ret;
	}

	nc_ctx->is_s2n = 1;
	nc_ctx->e = expt;
	nc_ctx->b = radix;
	nc_ctx->B = 2;
	nc_ctx->is_fixed = 1;
	nc_ctx->abs_pos = 0;
	nc_ctx->req_digits = 53 + 1;

	DUK__BI_PRINT("f", &nc_ctx->f);
	DUK_DDD(DUK_DDDPRINT("e=%ld", (long) nc_ctx->e));

	/*
	 *  Dragon4 slow path (binary) digit generation.
	 *  An extra digit is generated for rounding.
	 */

	duk__dragon4_prepare(nc_ctx);  /* setup many variables in nc_ctx */

	DUK_DDD(DUK_DDDPRINT("after prepare:"));
	DUK__BI_PRINT("r", &nc_ctx->r);
	DUK__BI_PRINT("s", &nc_ctx->s);
	DUK__BI_PRINT("mp", &nc_ctx->mp);
	DUK__BI_PRINT("mm", &nc_ctx->mm);

	duk__dragon4_scale(nc_ctx);

	DUK_DDD(DUK_DDDPRINT("after scale; k=%ld", (long) nc_ctx->k));
	DUK__BI_PRINT("r", &nc_ctx->r);
	DUK__BI_PRINT("s", &nc_ctx->s);
	DUK__BI_PRINT("mp", &nc_ctx->mp);
	DUK__BI_PRINT("mm", &nc_ctx->mm);

	duk__dragon4_generate(nc_ctx);

	DUK_ASSERT(nc_ctx->count == 53 + 1);

	/*
	 *  Convert binary digits into an IEEE double.  Need to handle
	 *  denormals and rounding correctly.
	 *
	 *  Some call sites currently assume the result is always a
	 *  non-fastint double.  If this is changed, check all call
	 *  sites.
	 */

	duk__dragon4_ctx_to_double(nc_ctx, &res);
	goto negcheck_and_ret;

 negcheck_and_ret:
	if (neg) {
		res = -res;
	}
	duk_pop(thr);
	duk_push_number(thr, (double) res);
	DUK_DDD(DUK_DDDPRINT("result: %!T", (duk_tval *) duk_get_tval(thr, -1)));
	return;

 parse_fail:
	DUK_DDD(DUK_DDDPRINT("parse failed"));
	duk_pop(thr);
	duk_push_nan(thr);
	return;

 parse_explimit_error:
	DUK_DDD(DUK_DDDPRINT("parse failed, internal error, can't return a value"));
	DUK_ERROR_RANGE(thr, "exponent too large");
	DUK_WO_NORETURN(return;);
}

DUK_INTERNAL void duk_numconv_parse(duk_hthread *thr, duk_small_int_t radix, duk_small_uint_t flags) {
	duk_native_stack_check(thr);
	duk__numconv_parse_raw(thr, radix, flags);
}

/* automatic undefs */
#undef DUK__BI_MAX_PARTS
#undef DUK__BI_PRINT
#undef DUK__DIGITCHAR
#undef DUK__DRAGON4_OUTPUT_PREINC
#undef DUK__IEEE_DOUBLE_EXP_BIAS
#undef DUK__IEEE_DOUBLE_EXP_MIN
#undef DUK__MAX_FORMATTED_LENGTH
#undef DUK__MAX_OUTPUT_DIGITS
#undef DUK__NO_EXP
#undef DUK__NUMCONV_CTX_BIGINTS_SIZE
#undef DUK__NUMCONV_CTX_NUM_BIGINTS
/*
 *  Regexp compilation.
 *
 *  See doc/regexp.rst for a discussion of the compilation approach and
 *  current limitations.
 *
 *  Regexp bytecode assumes jumps can be expressed with signed 32-bit
 *  integers.  Consequently the bytecode size must not exceed 0x7fffffffL.
 *  The implementation casts duk_size_t (buffer size) to duk_(u)int32_t
 *  in many places.  Although this could be changed, the bytecode format
 *  limit would still prevent regexps exceeding the signed 32-bit limit
 *  from working.
 *
 *  XXX: The implementation does not prevent bytecode from exceeding the
 *  maximum supported size.  This could be done by limiting the maximum
 *  input string size (assuming an upper bound can be computed for number
 *  of bytecode bytes emitted per input byte) or checking buffer maximum
 *  size when emitting bytecode (slower).
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_REGEXP_SUPPORT)

/*
 *  Helper macros
 */

#define DUK__RE_INITIAL_BUFSIZE 64

#define DUK__RE_BUFLEN(re_ctx) \
	DUK_BW_GET_SIZE(re_ctx->thr, &re_ctx->bw)

/*
 *  Disjunction struct: result of parsing a disjunction
 */

typedef struct {
	/* Number of characters that the atom matches (e.g. 3 for 'abc'),
	 * -1 if atom is complex and number of matched characters either
	 * varies or is not known.
	 */
	duk_int32_t charlen;

#if 0
	/* These are not needed to implement quantifier capture handling,
	 * but might be needed at some point.
	 */

	/* re_ctx->captures at start and end of atom parsing.
	 * Since 'captures' indicates highest capture number emitted
	 * so far in a DUK_REOP_SAVE, the captures numbers saved by
	 * the atom are: ]start_captures,end_captures].
	 */
	duk_uint32_t start_captures;
	duk_uint32_t end_captures;
#endif
} duk__re_disjunction_info;

/*
 *  Encoding helpers
 *
 *  Some of the typing is bytecode based, e.g. slice sizes are unsigned 32-bit
 *  even though the buffer operations will use duk_size_t.
 */

/* XXX: the insert helpers should ensure that the bytecode result is not
 * larger than expected (or at least assert for it).  Many things in the
 * bytecode, like skip offsets, won't work correctly if the bytecode is
 * larger than say 2G.
 */

DUK_LOCAL duk_uint32_t duk__encode_i32(duk_int32_t x) {
	if (x < 0) {
		return ((duk_uint32_t) (-x)) * 2 + 1;
	} else {
		return ((duk_uint32_t) x) * 2;
	}
}

/* XXX: return type should probably be duk_size_t, or explicit checks are needed for
 * maximum size.
 */
DUK_LOCAL duk_uint32_t duk__insert_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_uint32_t x) {
	duk_uint8_t buf[DUK_UNICODE_MAX_XUTF8_LENGTH];
	duk_small_int_t len;

	len = duk_unicode_encode_xutf8((duk_ucodepoint_t) x, buf);
	DUK_ASSERT(len >= 0);
	DUK_BW_INSERT_ENSURE_BYTES(re_ctx->thr, &re_ctx->bw, offset, buf, (duk_size_t) len);
	return (duk_uint32_t) len;
}

DUK_LOCAL void duk__append_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t x) {
	DUK_BW_WRITE_ENSURE_XUTF8(re_ctx->thr, &re_ctx->bw, x);
}

DUK_LOCAL void duk__append_7bit(duk_re_compiler_ctx *re_ctx, duk_uint32_t x) {
#if defined(DUK_USE_PREFER_SIZE)
	duk__append_u32(re_ctx, x);
#else
	DUK_ASSERT(x <= 0x7fU);
	DUK_BW_WRITE_ENSURE_U8(re_ctx->thr, &re_ctx->bw, (duk_uint8_t) x);
#endif
}

#if 0
DUK_LOCAL void duk__append_2bytes(duk_re_compiler_ctx *re_ctx, duk_uint8_t x, duk_uint8_t y) {
	DUK_BW_WRITE_ENSURE_U8_2(re_ctx->thr, &re_ctx->bw, x, y);
}
#endif

DUK_LOCAL duk_uint32_t duk__insert_i32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t x) {
	return duk__insert_u32(re_ctx, offset, duk__encode_i32(x));
}

DUK_LOCAL void duk__append_reop(duk_re_compiler_ctx *re_ctx, duk_uint32_t reop) {
	DUK_ASSERT(reop <= 0x7fU);
	(void) duk__append_7bit(re_ctx, reop);
}

#if 0  /* unused */
DUK_LOCAL void duk__append_i32(duk_re_compiler_ctx *re_ctx, duk_int32_t x) {
	duk__append_u32(re_ctx, duk__encode_i32(x));
}
#endif

/* special helper for emitting u16 lists (used for character ranges for built-in char classes) */
DUK_LOCAL void duk__append_u16_list(duk_re_compiler_ctx *re_ctx, const duk_uint16_t *values, duk_uint32_t count) {
	/* Call sites don't need the result length so it's not accumulated. */
	while (count-- > 0) {
		duk__append_u32(re_ctx, (duk_uint32_t) (*values++));
	}
}

DUK_LOCAL void duk__insert_slice(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_uint32_t data_offset, duk_uint32_t data_length) {
	DUK_BW_INSERT_ENSURE_SLICE(re_ctx->thr, &re_ctx->bw, offset, data_offset, data_length);
}

DUK_LOCAL void duk__append_slice(duk_re_compiler_ctx *re_ctx, duk_uint32_t data_offset, duk_uint32_t data_length) {
	DUK_BW_WRITE_ENSURE_SLICE(re_ctx->thr, &re_ctx->bw, data_offset, data_length);
}

DUK_LOCAL void duk__remove_slice(duk_re_compiler_ctx *re_ctx, duk_uint32_t data_offset, duk_uint32_t data_length) {
	DUK_BW_REMOVE_ENSURE_SLICE(re_ctx->thr, &re_ctx->bw, data_offset, data_length);
}

/*
 *  Insert a jump offset at 'offset' to complete an instruction
 *  (the jump offset is always the last component of an instruction).
 *  The 'skip' argument must be computed relative to 'offset',
 *  -without- taking into account the skip field being inserted.
 *
 *       ... A B C ins X Y Z ...   (ins may be a JUMP, SPLIT1/SPLIT2, etc)
 *   =>  ... A B C ins SKIP X Y Z
 *
 *  Computing the final (adjusted) skip value, which is relative to the
 *  first byte of the next instruction, is a bit tricky because of the
 *  variable length UTF-8 encoding.  See doc/regexp.rst for discussion.
 */
DUK_LOCAL duk_uint32_t duk__insert_jump_offset(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t skip) {
#if 0
	/* Iterative solution. */
	if (skip < 0) {
		duk_small_int_t len;
		/* two encoding attempts suffices */
		len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip));
		len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip - (duk_int32_t) len));
		DUK_ASSERT(duk_unicode_get_xutf8_length(duk__encode_i32(skip - (duk_int32_t) len)) == len);  /* no change */
		skip -= (duk_int32_t) len;
	}
#endif

#if defined(DUK_USE_PREFER_SIZE)
	/* Closed form solution, this produces smallest code.
	 * See re_neg_jump_offset (closed2).
	 */
	if (skip < 0) {
		skip--;
		if (skip < -0x3fL) {
			skip--;
		}
		if (skip < -0x3ffL) {
			skip--;
		}
		if (skip < -0x7fffL) {
			skip--;
		}
		if (skip < -0xfffffL) {
			skip--;
		}
		if (skip < -0x1ffffffL) {
			skip--;
		}
		if (skip < -0x3fffffffL) {
			skip--;
		}
	}
#else  /* DUK_USE_PREFER_SIZE */
	/* Closed form solution, this produces fastest code.
	 * See re_neg_jump_offset (closed1).
	 */
	if (skip < 0) {
		if (skip >= -0x3eL) {
			skip -= 1;
		} else if (skip >= -0x3fdL) {
			skip -= 2;
		} else if (skip >= -0x7ffcL) {
			skip -= 3;
		} else if (skip >= -0xffffbL) {
			skip -= 4;
		} else if (skip >= -0x1fffffaL) {
			skip -= 5;
		} else if (skip >= -0x3ffffff9L) {
			skip -= 6;
		} else {
			skip -= 7;
		}
	}
#endif  /* DUK_USE_PREFER_SIZE */

	return duk__insert_i32(re_ctx, offset, skip);
}

DUK_LOCAL duk_uint32_t duk__append_jump_offset(duk_re_compiler_ctx *re_ctx, duk_int32_t skip) {
	return (duk_uint32_t) duk__insert_jump_offset(re_ctx, (duk_uint32_t) DUK__RE_BUFLEN(re_ctx), skip);
}

/*
 *  duk_re_range_callback for generating character class ranges.
 *
 *  When ignoreCase is false, the range is simply emitted as is.  We don't,
 *  for instance, eliminate duplicates or overlapping ranges in a character
 *  class.
 *
 *  When ignoreCase is true but the 'direct' flag is set, the caller knows
 *  that the range canonicalizes to itself for case insensitive matching,
 *  so the range is emitted as is.  This is mainly useful for built-in ranges
 *  like \W.
 *
 *  Otherwise, when ignoreCase is true, the range needs to be normalized
 *  through canonicalization.  Unfortunately a canonicalized version of a
 *  continuous range is not necessarily continuous (e.g. [x-{] is continuous
 *  but [X-{] is not).  As a result, a single input range may expand to a lot
 *  of output ranges.  The current algorithm creates the canonicalized ranges
 *  footprint efficiently at the cost of compile time execution time; see
 *  doc/regexp.rst for discussion, and some more details below.
 *
 *  Note that the ctx->nranges is a context-wide temporary value.  This is OK
 *  because there cannot be multiple character classes being parsed
 *  simultaneously.
 *
 *  More detail on canonicalization:
 *
 *  Conceptually, a range is canonicalized by scanning the entire range,
 *  normalizing each codepoint by converting it to uppercase, and generating
 *  a set of result ranges.
 *
 *  Ideally a minimal set of output ranges would be emitted by merging all
 *  possible ranges even if they're emitted out of sequence.  Because the
 *  input string is also case normalized during matching, some codepoints
 *  never occur at runtime; these "don't care" codepoints can be included or
 *  excluded from ranges when merging/optimizing ranges.
 *
 *  The current algorithm does not do optimal range merging.  Rather, output
 *  codepoints are generated in sequence, and when the output codepoints are
 *  continuous (CP, CP+1, CP+2, ...), they are merged locally into as large a
 *  range as possible.  A small canonicalization bitmap is used to reduce
 *  actual codepoint canonicalizations which are quite slow at present.  The
 *  bitmap provides a "codepoint block is continuous with respect to
 *  canonicalization" for N-codepoint blocks.  This allows blocks to be
 *  skipped quickly.
 *
 *  There are a number of shortcomings and future work here:
 *
 *    - Individual codepoint normalizations are slow because they involve
 *      walking bit-packed rules without a lookup index.
 *
 *    - The conceptual algorithm needs to canonicalize every codepoint in the
 *      input range to figure out the output range(s).  Even with the small
 *      canonicalization bitmap the algorithm runs quite slowly for worst case
 *      inputs.  There are many data structure alternatives to improve this.
 *
 *    - While the current algorithm generates maximal output ranges when the
 *      output codepoints are emitted linearly, output ranges are not sorted or
 *      merged otherwise.  In the worst case a lot of ranges are emitted when
 *      most of the ranges could be merged.  In this process one could take
 *      advantage of "don't care" codepoints, which are never matched against at
 *      runtime due to canonicalization of input codepoints before comparison,
 *      to merge otherwise discontinuous output ranges.
 *
 *    - The runtime data structure is just a linear list of ranges to match
 *      against.  This can be quite slow if there are a lot of output ranges.
 *      There are various ways to make matching against the ranges faster,
 *      e.g. sorting the ranges and using a binary search; skip lists; tree
 *      based representations; full or approximate codepoint bitmaps, etc.
 *
 *    - Only BMP is supported, codepoints above BMP are assumed to canonicalize
 *      to themselves.  For now this is one place where we don't want to
 *      support chars outside the BMP, because the exhaustive search would be
 *      massively larger.  It would be possible to support non-BMP with a
 *      different algorithm, or perhaps doing case normalization only at match
 *      time.
 */

DUK_LOCAL void duk__regexp_emit_range(duk_re_compiler_ctx *re_ctx, duk_codepoint_t r1, duk_codepoint_t r2) {
	DUK_ASSERT(r2 >= r1);
	duk__append_u32(re_ctx, (duk_uint32_t) r1);
	duk__append_u32(re_ctx, (duk_uint32_t) r2);
	re_ctx->nranges++;
}

#if defined(DUK_USE_REGEXP_CANON_BITMAP)
/* Find next canonicalization discontinuity (conservative estimate) starting
 * from 'start', not exceeding 'end'.  If continuity is fine up to 'end'
 * inclusive, returns end.  Minimum possible return value is start.
 */
DUK_LOCAL duk_codepoint_t duk__re_canon_next_discontinuity(duk_codepoint_t start, duk_codepoint_t end) {
	duk_uint_t start_blk;
	duk_uint_t end_blk;
	duk_uint_t blk;
	duk_uint_t offset;
	duk_uint8_t mask;

	/* Inclusive block range. */
	DUK_ASSERT(start >= 0);
	DUK_ASSERT(end >= 0);
	DUK_ASSERT(end >= start);
	start_blk = (duk_uint_t) (start >> DUK_CANON_BITMAP_BLKSHIFT);
	end_blk = (duk_uint_t) (end >> DUK_CANON_BITMAP_BLKSHIFT);

	for (blk = start_blk; blk <= end_blk; blk++) {
		offset = blk >> 3;
		mask = 1U << (blk & 0x07);
		if (offset >= sizeof(duk_unicode_re_canon_bitmap)) {
			/* Reached non-BMP range which is assumed continuous. */
			return end;
		}
		DUK_ASSERT(offset < sizeof(duk_unicode_re_canon_bitmap));
		if ((duk_unicode_re_canon_bitmap[offset] & mask) == 0) {
			/* Block is discontinuous, continuity is guaranteed
			 * only up to end of previous block (+1 for exclusive
			 * return value => start of current block).  Start
			 * block requires special handling.
			 */
			if (blk > start_blk) {
				return (duk_codepoint_t) (blk << DUK_CANON_BITMAP_BLKSHIFT);
			} else {
				return start;
			}
		}
	}
	DUK_ASSERT(blk == end_blk + 1);  /* Reached end block which is continuous. */
	return end;
}
#else  /* DUK_USE_REGEXP_CANON_BITMAP */
DUK_LOCAL duk_codepoint_t duk__re_canon_next_discontinuity(duk_codepoint_t start, duk_codepoint_t end) {
	DUK_ASSERT(start >= 0);
	DUK_ASSERT(end >= 0);
	DUK_ASSERT(end >= start);
	if (start >= 0x10000) {
		/* Even without the bitmap, treat non-BMP as continuous. */
		return end;
	}
	return start;
}
#endif  /* DUK_USE_REGEXP_CANON_BITMAP */

DUK_LOCAL void duk__regexp_generate_ranges(void *userdata, duk_codepoint_t r1, duk_codepoint_t r2, duk_bool_t direct) {
	duk_re_compiler_ctx *re_ctx = (duk_re_compiler_ctx *) userdata;
	duk_codepoint_t r_start;
	duk_codepoint_t r_end;
	duk_codepoint_t i;
	duk_codepoint_t t;
	duk_codepoint_t r_disc;

	DUK_DD(DUK_DDPRINT("duk__regexp_generate_ranges(): re_ctx=%p, range=[%ld,%ld] direct=%ld",
	                   (void *) re_ctx, (long) r1, (long) r2, (long) direct));

	DUK_ASSERT(r2 >= r1);  /* SyntaxError for out of order range. */

	if (direct || (re_ctx->re_flags & DUK_RE_FLAG_IGNORE_CASE) == 0) {
		DUK_DD(DUK_DDPRINT("direct or not case sensitive, emit range: [%ld,%ld]", (long) r1, (long) r2));
		duk__regexp_emit_range(re_ctx, r1, r2);
		return;
	}

	DUK_DD(DUK_DDPRINT("case sensitive, process range: [%ld,%ld]", (long) r1, (long) r2));

	r_start = duk_unicode_re_canonicalize_char(re_ctx->thr, r1);
	r_end = r_start;

	for (i = r1 + 1; i <= r2;) {
		/* Input codepoint space processed up to i-1, and
		 * current range in r_{start,end} is up-to-date
		 * (inclusive) and may either break or continue.
		 */
		r_disc = duk__re_canon_next_discontinuity(i, r2);
		DUK_ASSERT(r_disc >= i);
		DUK_ASSERT(r_disc <= r2);

		r_end += r_disc - i;  /* May be zero. */
		t = duk_unicode_re_canonicalize_char(re_ctx->thr, r_disc);
		if (t == r_end + 1) {
			/* Not actually a discontinuity, continue range
			 * to r_disc and recheck.
			 */
			r_end = t;
		} else {
			duk__regexp_emit_range(re_ctx, r_start, r_end);
			r_start = t;
			r_end = t;
		}
		i = r_disc + 1;  /* Guarantees progress. */
	}
	duk__regexp_emit_range(re_ctx, r_start, r_end);

#if 0  /* Exhaustive search, very slow. */
	r_start = duk_unicode_re_canonicalize_char(re_ctx->thr, r1);
	r_end = r_start;
	for (i = r1 + 1; i <= r2; i++) {
		t = duk_unicode_re_canonicalize_char(re_ctx->thr, i);
		if (t == r_end + 1) {
			r_end = t;
		} else {
			DUK_DD(DUK_DDPRINT("canonicalized, emit range: [%ld,%ld]", (long) r_start, (long) r_end));
			duk__append_u32(re_ctx, (duk_uint32_t) r_start);
			duk__append_u32(re_ctx, (duk_uint32_t) r_end);
			re_ctx->nranges++;
			r_start = t;
			r_end = t;
		}
	}
	DUK_DD(DUK_DDPRINT("canonicalized, emit range: [%ld,%ld]", (long) r_start, (long) r_end));
	duk__append_u32(re_ctx, (duk_uint32_t) r_start);
	duk__append_u32(re_ctx, (duk_uint32_t) r_end);
	re_ctx->nranges++;
#endif
}

/*
 *  Parse regexp Disjunction.  Most of regexp compilation happens here.
 *
 *  Handles Disjunction, Alternative, and Term productions directly without
 *  recursion.  The only constructs requiring recursion are positive/negative
 *  lookaheads, capturing parentheses, and non-capturing parentheses.
 *
 *  The function determines whether the entire disjunction is a 'simple atom'
 *  (see doc/regexp.rst discussion on 'simple quantifiers') and if so,
 *  returns the atom character length which is needed by the caller to keep
 *  track of its own atom character length.  A disjunction with more than one
 *  alternative is never considered a simple atom (although in some cases
 *  that might be the case).
 *
 *  Return value: simple atom character length or < 0 if not a simple atom.
 *  Appends the bytecode for the disjunction matcher to the end of the temp
 *  buffer.
 *
 *  Regexp top level structure is:
 *
 *    Disjunction = Term*
 *                | Term* | Disjunction
 *
 *    Term = Assertion
 *         | Atom
 *         | Atom Quantifier
 *
 *  An empty Term sequence is a valid disjunction alternative (e.g. /|||c||/).
 *
 *  Notes:
 *
 *    * Tracking of the 'simple-ness' of the current atom vs. the entire
 *      disjunction are separate matters.  For instance, the disjunction
 *      may be complex, but individual atoms may be simple.  Furthermore,
 *      simple quantifiers are used whenever possible, even if the
 *      disjunction as a whole is complex.
 *
 *    * The estimate of whether an atom is simple is conservative now,
 *      and it would be possible to expand it.  For instance, captures
 *      cause the disjunction to be marked complex, even though captures
 *      -can- be handled by simple quantifiers with some minor modifications.
 *
 *    * Disjunction 'tainting' as 'complex' is handled at the end of the
 *      main for loop collectively for atoms.  Assertions, quantifiers,
 *      and '|' tokens need to taint the result manually if necessary.
 *      Assertions cannot add to result char length, only atoms (and
 *      quantifiers) can; currently quantifiers will taint the result
 *      as complex though.
 */

DUK_LOCAL const duk_uint16_t * const duk__re_range_lookup1[3] = {
	duk_unicode_re_ranges_digit,
	duk_unicode_re_ranges_white,
	duk_unicode_re_ranges_wordchar
};
DUK_LOCAL const duk_uint8_t duk__re_range_lookup2[3] = {
	sizeof(duk_unicode_re_ranges_digit) / (2 * sizeof(duk_uint16_t)),
	sizeof(duk_unicode_re_ranges_white) / (2 * sizeof(duk_uint16_t)),
	sizeof(duk_unicode_re_ranges_wordchar) / (2 * sizeof(duk_uint16_t))
};

DUK_LOCAL void duk__append_range_atom_matcher(duk_re_compiler_ctx *re_ctx, duk_small_uint_t re_op, const duk_uint16_t *ranges, duk_small_uint_t count) {
#if 0
	DUK_ASSERT(re_op <= 0x7fUL);
	DUK_ASSERT(count <= 0x7fUL);
	duk__append_2bytes(re_ctx, (duk_uint8_t) re_op, (duk_uint8_t) count);
#endif
	duk__append_reop(re_ctx, re_op);
	duk__append_7bit(re_ctx, count);
	duk__append_u16_list(re_ctx, ranges, count * 2);
}

DUK_LOCAL void duk__parse_disjunction(duk_re_compiler_ctx *re_ctx, duk_bool_t expect_eof, duk__re_disjunction_info *out_atom_info) {
	duk_int32_t atom_start_offset = -1;                   /* negative -> no atom matched on previous round */
	duk_int32_t atom_char_length = 0;                     /* negative -> complex atom */
	duk_uint32_t atom_start_captures = re_ctx->captures;  /* value of re_ctx->captures at start of atom */
	duk_int32_t unpatched_disjunction_split = -1;
	duk_int32_t unpatched_disjunction_jump = -1;
	duk_uint32_t entry_offset = (duk_uint32_t) DUK__RE_BUFLEN(re_ctx);
	duk_int32_t res_charlen = 0;  /* -1 if disjunction is complex, char length if simple */
	duk__re_disjunction_info tmp_disj;

	DUK_ASSERT(out_atom_info != NULL);

	duk_native_stack_check(re_ctx->thr);
	if (re_ctx->recursion_depth >= re_ctx->recursion_limit) {
		DUK_ERROR_RANGE(re_ctx->thr, DUK_STR_REGEXP_COMPILER_RECURSION_LIMIT);
		DUK_WO_NORETURN(return;);
	}
	re_ctx->recursion_depth++;

#if 0
	out_atom_info->start_captures = re_ctx->captures;
#endif

	for (;;) {
		/* atom_char_length, atom_start_offset, atom_start_offset reflect the
		 * atom matched on the previous loop.  If a quantifier is encountered
		 * on this loop, these are needed to handle the quantifier correctly.
		 * new_atom_char_length etc are for the atom parsed on this round;
		 * they're written to atom_char_length etc at the end of the round.
		 */
		duk_int32_t new_atom_char_length;   /* char length of the atom parsed in this loop */
		duk_int32_t new_atom_start_offset;  /* bytecode start offset of the atom parsed in this loop
		                                     * (allows quantifiers to copy the atom bytecode)
		                                     */
		duk_uint32_t new_atom_start_captures;  /* re_ctx->captures at the start of the atom parsed in this loop */

		duk_lexer_parse_re_token(&re_ctx->lex, &re_ctx->curr_token);

		DUK_DD(DUK_DDPRINT("re token: %ld (num=%ld, char=%c)",
		                   (long) re_ctx->curr_token.t,
		                   (long) re_ctx->curr_token.num,
		                   (re_ctx->curr_token.num >= 0x20 && re_ctx->curr_token.num <= 0x7e) ?
		                   (int) re_ctx->curr_token.num : (int) '?'));

		/* set by atom case clauses */
		new_atom_start_offset = -1;
		new_atom_char_length = -1;
		new_atom_start_captures = re_ctx->captures;

		switch (re_ctx->curr_token.t) {
		case DUK_RETOK_DISJUNCTION: {
			/*
			 *  The handling here is a bit tricky.  If a previous '|' has been processed,
			 *  we have a pending split1 and a pending jump (for a previous match).  These
			 *  need to be back-patched carefully.  See docs for a detailed example.
			 */

			/* patch pending jump and split */
			if (unpatched_disjunction_jump >= 0) {
				duk_uint32_t offset;

				DUK_ASSERT(unpatched_disjunction_split >= 0);
				offset = (duk_uint32_t) unpatched_disjunction_jump;
				offset += duk__insert_jump_offset(re_ctx,
				                                  offset,
				                                  (duk_int32_t) (DUK__RE_BUFLEN(re_ctx) - offset));
				/* offset is now target of the pending split (right after jump) */
				duk__insert_jump_offset(re_ctx,
				                        (duk_uint32_t) unpatched_disjunction_split,
				                        (duk_int32_t) offset - unpatched_disjunction_split);
			}

			/* add a new pending split to the beginning of the entire disjunction */
			(void) duk__insert_u32(re_ctx,
			                       entry_offset,
			                       DUK_REOP_SPLIT1);   /* prefer direct execution */
			unpatched_disjunction_split = (duk_int32_t) (entry_offset + 1);   /* +1 for opcode */

			/* add a new pending match jump for latest finished alternative */
			duk__append_reop(re_ctx, DUK_REOP_JUMP);
			unpatched_disjunction_jump = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);

			/* 'taint' result as complex */
			res_charlen = -1;
			break;
		}
		case DUK_RETOK_QUANTIFIER: {
			if (atom_start_offset < 0) {
				DUK_ERROR_SYNTAX(re_ctx->thr, DUK_STR_INVALID_QUANTIFIER_NO_ATOM);
				DUK_WO_NORETURN(return;);
			}
			if (re_ctx->curr_token.qmin > re_ctx->curr_token.qmax) {
				DUK_ERROR_SYNTAX(re_ctx->thr, DUK_STR_INVALID_QUANTIFIER_VALUES);
				DUK_WO_NORETURN(return;);
			}
			if (atom_char_length >= 0) {
				/*
				 *  Simple atom
				 *
				 *  If atom_char_length is zero, we'll have unbounded execution time for e.g.
				 *  /()*x/.exec('x').  We can't just skip the match because it might have some
				 *  side effects (for instance, if we allowed captures in simple atoms, the
				 *  capture needs to happen).  The simple solution below is to force the
				 *  quantifier to match at most once, since the additional matches have no effect.
				 *
				 *  With a simple atom there can be no capture groups, so no captures need
				 *  to be reset.
				 */
				duk_int32_t atom_code_length;
				duk_uint32_t offset;
				duk_uint32_t qmin, qmax;

				qmin = re_ctx->curr_token.qmin;
				qmax = re_ctx->curr_token.qmax;
				if (atom_char_length == 0) {
					/* qmin and qmax will be 0 or 1 */
					if (qmin > 1) {
						qmin = 1;
					}
					if (qmax > 1) {
						qmax = 1;
					}
				}

				duk__append_reop(re_ctx, DUK_REOP_MATCH);   /* complete 'sub atom' */
				atom_code_length = (duk_int32_t) (DUK__RE_BUFLEN(re_ctx) - (duk_size_t) atom_start_offset);

				offset = (duk_uint32_t) atom_start_offset;
				if (re_ctx->curr_token.greedy) {
					offset += duk__insert_u32(re_ctx, offset, DUK_REOP_SQGREEDY);
					offset += duk__insert_u32(re_ctx, offset, qmin);
					offset += duk__insert_u32(re_ctx, offset, qmax);
					offset += duk__insert_u32(re_ctx, offset, (duk_uint32_t) atom_char_length);
					offset += duk__insert_jump_offset(re_ctx, offset, atom_code_length);
				} else {
					offset += duk__insert_u32(re_ctx, offset, DUK_REOP_SQMINIMAL);
					offset += duk__insert_u32(re_ctx, offset, qmin);
					offset += duk__insert_u32(re_ctx, offset, qmax);
					offset += duk__insert_jump_offset(re_ctx, offset, atom_code_length);
				}
				DUK_UNREF(offset);  /* silence scan-build warning */
			} else {
				/*
				 *  Complex atom
				 *
				 *  The original code is used as a template, and removed at the end
				 *  (this differs from the handling of simple quantifiers).
				 *
				 *  NOTE: there is no current solution for empty atoms in complex
				 *  quantifiers.  This would need some sort of a 'progress' instruction.
				 *
				 *  XXX: impose limit on maximum result size, i.e. atom_code_len * atom_copies?
				 */
				duk_int32_t atom_code_length;
				duk_uint32_t atom_copies;
				duk_uint32_t tmp_qmin, tmp_qmax;

				/* pre-check how many atom copies we're willing to make (atom_copies not needed below) */
				atom_copies = (re_ctx->curr_token.qmax == DUK_RE_QUANTIFIER_INFINITE) ?
				              re_ctx->curr_token.qmin : re_ctx->curr_token.qmax;
				if (atom_copies > DUK_RE_MAX_ATOM_COPIES) {
					DUK_ERROR_RANGE(re_ctx->thr, DUK_STR_QUANTIFIER_TOO_MANY_COPIES);
					DUK_WO_NORETURN(return;);
				}

				/* wipe the capture range made by the atom (if any) */
				DUK_ASSERT(atom_start_captures <= re_ctx->captures);
				if (atom_start_captures != re_ctx->captures) {
					DUK_ASSERT(atom_start_captures < re_ctx->captures);
					DUK_DDD(DUK_DDDPRINT("must wipe ]atom_start_captures,re_ctx->captures]: ]%ld,%ld]",
					                     (long) atom_start_captures, (long) re_ctx->captures));

					/* insert (DUK_REOP_WIPERANGE, start, count) in reverse order so the order ends up right */
					duk__insert_u32(re_ctx, (duk_uint32_t) atom_start_offset, (re_ctx->captures - atom_start_captures) * 2U);
					duk__insert_u32(re_ctx, (duk_uint32_t) atom_start_offset, (atom_start_captures + 1) * 2);
					duk__insert_u32(re_ctx, (duk_uint32_t) atom_start_offset, DUK_REOP_WIPERANGE);
				} else {
					DUK_DDD(DUK_DDDPRINT("no need to wipe captures: atom_start_captures == re_ctx->captures == %ld",
					                     (long) atom_start_captures));
				}

				atom_code_length = (duk_int32_t) DUK__RE_BUFLEN(re_ctx) - atom_start_offset;

				/* insert the required matches (qmin) by copying the atom */
				tmp_qmin = re_ctx->curr_token.qmin;
				tmp_qmax = re_ctx->curr_token.qmax;
				while (tmp_qmin > 0) {
					duk__append_slice(re_ctx, (duk_uint32_t) atom_start_offset, (duk_uint32_t) atom_code_length);
					tmp_qmin--;
					if (tmp_qmax != DUK_RE_QUANTIFIER_INFINITE) {
						tmp_qmax--;
					}
				}
				DUK_ASSERT(tmp_qmin == 0);

				/* insert code for matching the remainder - infinite or finite */
				if (tmp_qmax == DUK_RE_QUANTIFIER_INFINITE) {
					/* reuse last emitted atom for remaining 'infinite' quantifier */

					if (re_ctx->curr_token.qmin == 0) {
						/* Special case: original qmin was zero so there is nothing
						 * to repeat.  Emit an atom copy but jump over it here.
						 */
						duk__append_reop(re_ctx, DUK_REOP_JUMP);
						duk__append_jump_offset(re_ctx, atom_code_length);
						duk__append_slice(re_ctx, (duk_uint32_t) atom_start_offset, (duk_uint32_t) atom_code_length);
					}
					if (re_ctx->curr_token.greedy) {
						duk__append_reop(re_ctx, DUK_REOP_SPLIT2);   /* prefer jump */
					} else {
						duk__append_reop(re_ctx, DUK_REOP_SPLIT1);   /* prefer direct */
					}
					duk__append_jump_offset(re_ctx, -atom_code_length - 1);  /* -1 for opcode */
				} else {
					/*
					 *  The remaining matches are emitted as sequence of SPLITs and atom
					 *  copies; the SPLITs skip the remaining copies and match the sequel.
					 *  This sequence needs to be emitted starting from the last copy
					 *  because the SPLITs are variable length due to the variable length
					 *  skip offset.  This causes a lot of memory copying now.
					 *
					 *  Example structure (greedy, match maximum # atoms):
					 *
					 *      SPLIT1 LSEQ
					 *      (atom)
					 *      SPLIT1 LSEQ    ; <- the byte length of this instruction is needed
					 *      (atom)         ; to encode the above SPLIT1 correctly
					 *      ...
					 *   LSEQ:
					 */
					duk_uint32_t offset = (duk_uint32_t) DUK__RE_BUFLEN(re_ctx);
					while (tmp_qmax > 0) {
						duk__insert_slice(re_ctx, offset, (duk_uint32_t) atom_start_offset, (duk_uint32_t) atom_code_length);
						if (re_ctx->curr_token.greedy) {
							duk__insert_u32(re_ctx, offset, DUK_REOP_SPLIT1);   /* prefer direct */
						} else {
							duk__insert_u32(re_ctx, offset, DUK_REOP_SPLIT2);   /* prefer jump */
						}
						duk__insert_jump_offset(re_ctx,
						                        offset + 1,   /* +1 for opcode */
						                        (duk_int32_t) (DUK__RE_BUFLEN(re_ctx) - (offset + 1)));
						tmp_qmax--;
					}
				}

				/* remove the original 'template' atom */
				duk__remove_slice(re_ctx, (duk_uint32_t) atom_start_offset, (duk_uint32_t) atom_code_length);
			}

			/* 'taint' result as complex */
			res_charlen = -1;
			break;
		}
		case DUK_RETOK_ASSERT_START: {
			duk__append_reop(re_ctx, DUK_REOP_ASSERT_START);
			break;
		}
		case DUK_RETOK_ASSERT_END: {
			duk__append_reop(re_ctx, DUK_REOP_ASSERT_END);
			break;
		}
		case DUK_RETOK_ASSERT_WORD_BOUNDARY: {
			duk__append_reop(re_ctx, DUK_REOP_ASSERT_WORD_BOUNDARY);
			break;
		}
		case DUK_RETOK_ASSERT_NOT_WORD_BOUNDARY: {
			duk__append_reop(re_ctx, DUK_REOP_ASSERT_NOT_WORD_BOUNDARY);
			break;
		}
		case DUK_RETOK_ASSERT_START_POS_LOOKAHEAD:
		case DUK_RETOK_ASSERT_START_NEG_LOOKAHEAD: {
			duk_uint32_t offset;
			duk_uint32_t opcode = (re_ctx->curr_token.t == DUK_RETOK_ASSERT_START_POS_LOOKAHEAD) ?
			                      DUK_REOP_LOOKPOS : DUK_REOP_LOOKNEG;

			offset = (duk_uint32_t) DUK__RE_BUFLEN(re_ctx);
			duk__parse_disjunction(re_ctx, 0, &tmp_disj);
			duk__append_reop(re_ctx, DUK_REOP_MATCH);

			(void) duk__insert_u32(re_ctx, offset, opcode);
			(void) duk__insert_jump_offset(re_ctx,
			                               offset + 1,   /* +1 for opcode */
			                               (duk_int32_t) (DUK__RE_BUFLEN(re_ctx) - (offset + 1)));

			/* 'taint' result as complex -- this is conservative,
			 * as lookaheads do not backtrack.
			 */
			res_charlen = -1;
			break;
		}
		case DUK_RETOK_ATOM_PERIOD: {
			new_atom_char_length = 1;
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			duk__append_reop(re_ctx, DUK_REOP_PERIOD);
			break;
		}
		case DUK_RETOK_ATOM_CHAR: {
			/* Note: successive characters could be joined into string matches
			 * but this is not trivial (consider e.g. '/xyz+/); see docs for
			 * more discussion.
			 *
			 * No support for \u{H+} yet.  While only BMP Unicode escapes are
			 * supported for RegExps at present, 'ch' may still be a non-BMP
			 * codepoint if it is decoded straight from source text UTF-8.
			 * There's no non-BMP support yet so this is handled simply by
			 * matching the non-BMP character (which is custom behavior).
			 */
			duk_uint32_t ch;

			new_atom_char_length = 1;
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			duk__append_reop(re_ctx, DUK_REOP_CHAR);
			ch = re_ctx->curr_token.num;
			if (re_ctx->re_flags & DUK_RE_FLAG_IGNORE_CASE) {
				ch = (duk_uint32_t) duk_unicode_re_canonicalize_char(re_ctx->thr, (duk_codepoint_t) ch);
			}
			duk__append_u32(re_ctx, ch);
			break;
		}
		case DUK_RETOK_ATOM_DIGIT:
		case DUK_RETOK_ATOM_NOT_DIGIT:
		case DUK_RETOK_ATOM_WHITE:
		case DUK_RETOK_ATOM_NOT_WHITE:
		case DUK_RETOK_ATOM_WORD_CHAR:
		case DUK_RETOK_ATOM_NOT_WORD_CHAR: {
			duk_small_uint_t re_op;
			duk_small_uint_t idx;

			new_atom_char_length = 1;
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);

			DUK_ASSERT((DUK_RETOK_ATOM_DIGIT & 0x01) != 0);
			DUK_ASSERT((DUK_RETOK_ATOM_WHITE & 0x01) != 0);
			DUK_ASSERT((DUK_RETOK_ATOM_WORD_CHAR & 0x01) != 0);
			DUK_ASSERT((DUK_RETOK_ATOM_NOT_DIGIT & 0x01) == 0);
			DUK_ASSERT((DUK_RETOK_ATOM_NOT_WHITE & 0x01) == 0);
			DUK_ASSERT((DUK_RETOK_ATOM_NOT_WORD_CHAR & 0x01) == 0);
			re_op = (re_ctx->curr_token.t & 0x01) ? DUK_REOP_RANGES : DUK_REOP_INVRANGES;

			DUK_ASSERT(DUK_RETOK_ATOM_WHITE == DUK_RETOK_ATOM_DIGIT + 2);
			DUK_ASSERT(DUK_RETOK_ATOM_WORD_CHAR == DUK_RETOK_ATOM_DIGIT + 4);
			idx = (duk_small_uint_t) ((re_ctx->curr_token.t - DUK_RETOK_ATOM_DIGIT) >> 1U);
			DUK_ASSERT(idx <= 2U);  /* Assume continuous token numbers; also checks negative underflow. */

			duk__append_range_atom_matcher(re_ctx, re_op, duk__re_range_lookup1[idx], duk__re_range_lookup2[idx]);
			break;
		}
		case DUK_RETOK_ATOM_BACKREFERENCE: {
			duk_uint32_t backref = (duk_uint32_t) re_ctx->curr_token.num;
			if (backref > re_ctx->highest_backref) {
				re_ctx->highest_backref = backref;
			}
			new_atom_char_length = -1;   /* mark as complex */
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			duk__append_reop(re_ctx, DUK_REOP_BACKREFERENCE);
			duk__append_u32(re_ctx, backref);
			break;
		}
		case DUK_RETOK_ATOM_START_CAPTURE_GROUP: {
			duk_uint32_t cap;

			new_atom_char_length = -1;   /* mark as complex (capture handling) */
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			cap = ++re_ctx->captures;
			duk__append_reop(re_ctx, DUK_REOP_SAVE);
			duk__append_u32(re_ctx, cap * 2);
			duk__parse_disjunction(re_ctx, 0, &tmp_disj);  /* retval (sub-atom char length) unused, tainted as complex above */
			duk__append_reop(re_ctx, DUK_REOP_SAVE);
			duk__append_u32(re_ctx, cap * 2 + 1);
			break;
		}
		case DUK_RETOK_ATOM_START_NONCAPTURE_GROUP: {
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			duk__parse_disjunction(re_ctx, 0, &tmp_disj);
			new_atom_char_length = tmp_disj.charlen;
			break;
		}
		case DUK_RETOK_ATOM_START_CHARCLASS:
		case DUK_RETOK_ATOM_START_CHARCLASS_INVERTED: {
			/*
			 *  Range parsing is done with a special lexer function which calls
			 *  us for every range parsed.  This is different from how rest of
			 *  the parsing works, but avoids a heavy, arbitrary size intermediate
			 *  value type to hold the ranges.
			 *
			 *  Another complication is the handling of character ranges when
			 *  case insensitive matching is used (see docs for discussion).
			 *  The range handler callback given to the lexer takes care of this
			 *  as well.
			 *
			 *  Note that duplicate ranges are not eliminated when parsing character
			 *  classes, so that canonicalization of
			 *
			 *    [0-9a-fA-Fx-{]
			 *
			 *  creates the result (note the duplicate ranges):
			 *
			 *    [0-9A-FA-FX-Z{-{]
			 *
			 *  where [x-{] is split as a result of canonicalization.  The duplicate
			 *  ranges are not a semantics issue: they work correctly.
			 */

			duk_uint32_t offset;

			DUK_DD(DUK_DDPRINT("character class"));

			/* insert ranges instruction, range count patched in later */
			new_atom_char_length = 1;
			new_atom_start_offset = (duk_int32_t) DUK__RE_BUFLEN(re_ctx);
			duk__append_reop(re_ctx,
			                 (re_ctx->curr_token.t == DUK_RETOK_ATOM_START_CHARCLASS) ?
			                 DUK_REOP_RANGES : DUK_REOP_INVRANGES);
			offset = (duk_uint32_t) DUK__RE_BUFLEN(re_ctx);    /* patch in range count later */

			/* parse ranges until character class ends */
			re_ctx->nranges = 0;    /* note: ctx-wide temporary */
			duk_lexer_parse_re_ranges(&re_ctx->lex, duk__regexp_generate_ranges, (void *) re_ctx);

			/* insert range count */
			duk__insert_u32(re_ctx, offset, re_ctx->nranges);
			break;
		}
		case DUK_RETOK_ATOM_END_GROUP: {
			if (expect_eof) {
				DUK_ERROR_SYNTAX(re_ctx->thr, DUK_STR_UNEXPECTED_CLOSING_PAREN);
				DUK_WO_NORETURN(return;);
			}
			goto done;
		}
		case DUK_RETOK_EOF: {
			if (!expect_eof) {
				DUK_ERROR_SYNTAX(re_ctx->thr, DUK_STR_UNEXPECTED_END_OF_PATTERN);
				DUK_WO_NORETURN(return;);
			}
			goto done;
		}
		default: {
			DUK_ERROR_SYNTAX(re_ctx->thr, DUK_STR_UNEXPECTED_REGEXP_TOKEN);
			DUK_WO_NORETURN(return;);
		}
		}

		/* a complex (new) atom taints the result */
		if (new_atom_start_offset >= 0) {
			if (new_atom_char_length < 0) {
				res_charlen = -1;
			} else if (res_charlen >= 0) {
				/* only advance if not tainted */
				res_charlen += new_atom_char_length;
			}
		}

		/* record previous atom info in case next token is a quantifier */
		atom_start_offset = new_atom_start_offset;
		atom_char_length = new_atom_char_length;
		atom_start_captures = new_atom_start_captures;
	}

 done:

	/* finish up pending jump and split for last alternative */
	if (unpatched_disjunction_jump >= 0) {
		duk_uint32_t offset;

		DUK_ASSERT(unpatched_disjunction_split >= 0);
		offset = (duk_uint32_t) unpatched_disjunction_jump;
		offset += duk__insert_jump_offset(re_ctx,
		                                  offset,
		                                  (duk_int32_t) (DUK__RE_BUFLEN(re_ctx) - offset));
		/* offset is now target of the pending split (right after jump) */
		duk__insert_jump_offset(re_ctx,
		                        (duk_uint32_t) unpatched_disjunction_split,
		                        (duk_int32_t) offset - unpatched_disjunction_split);
	}

#if 0
	out_atom_info->end_captures = re_ctx->captures;
#endif
	out_atom_info->charlen = res_charlen;
	DUK_DDD(DUK_DDDPRINT("parse disjunction finished: charlen=%ld",
	                     (long) out_atom_info->charlen));

	re_ctx->recursion_depth--;
}

/*
 *  Flags parsing (see E5 Section 15.10.4.1).
 */

DUK_LOCAL duk_uint32_t duk__parse_regexp_flags(duk_hthread *thr, duk_hstring *h) {
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;
	duk_uint32_t flags = 0;

	p = DUK_HSTRING_GET_DATA(h);
	p_end = p + DUK_HSTRING_GET_BYTELEN(h);

	/* Note: can be safely scanned as bytes (undecoded) */

	while (p < p_end) {
		duk_uint8_t c = *p++;
		switch (c) {
		case (duk_uint8_t) 'g': {
			if (flags & DUK_RE_FLAG_GLOBAL) {
				goto flags_error;
			}
			flags |= DUK_RE_FLAG_GLOBAL;
			break;
		}
		case (duk_uint8_t) 'i': {
			if (flags & DUK_RE_FLAG_IGNORE_CASE) {
				goto flags_error;
			}
			flags |= DUK_RE_FLAG_IGNORE_CASE;
			break;
		}
		case (duk_uint8_t) 'm': {
			if (flags & DUK_RE_FLAG_MULTILINE) {
				goto flags_error;
			}
			flags |= DUK_RE_FLAG_MULTILINE;
			break;
		}
		default: {
			goto flags_error;
		}
		}
	}

	return flags;

 flags_error:
	DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_REGEXP_FLAGS);
	DUK_WO_NORETURN(return 0U;);
}

/*
 *  Create escaped RegExp source (E5 Section 15.10.3).
 *
 *  The current approach is to special case the empty RegExp
 *  ('' -> '(?:)') and otherwise replace unescaped '/' characters
 *  with '\/' regardless of where they occur in the regexp.
 *
 *  Note that normalization does not seem to be necessary for
 *  RegExp literals (e.g. '/foo/') because to be acceptable as
 *  a RegExp literal, the text between forward slashes must
 *  already match the escaping requirements (e.g. must not contain
 *  unescaped forward slashes or be empty).  Escaping IS needed
 *  for expressions like 'new Regexp("...", "")' however.
 *  Currently, we re-escape in either case.
 *
 *  Also note that we process the source here in UTF-8 encoded
 *  form.  This is correct, because any non-ASCII characters are
 *  passed through without change.
 */

DUK_LOCAL void duk__create_escaped_source(duk_hthread *thr, int idx_pattern) {
	duk_hstring *h;
	const duk_uint8_t *p;
	duk_bufwriter_ctx bw_alloc;
	duk_bufwriter_ctx *bw;
	duk_uint8_t *q;
	duk_size_t i, n;
	duk_uint_fast8_t c_prev, c;

	h = duk_known_hstring(thr, idx_pattern);
	p = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h);
	n = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h);

	if (n == 0) {
		duk_push_literal(thr, "(?:)");
		return;
	}

	bw = &bw_alloc;
	DUK_BW_INIT_PUSHBUF(thr, bw, n);
	q = DUK_BW_GET_PTR(thr, bw);

	c_prev = (duk_uint_fast8_t) 0;

	for (i = 0; i < n; i++) {
		c = p[i];

		q = DUK_BW_ENSURE_RAW(thr, bw, 2, q);

		if (c == (duk_uint_fast8_t) '/' && c_prev != (duk_uint_fast8_t) '\\') {
			/* Unescaped '/' ANYWHERE in the regexp (in disjunction,
			 * inside a character class, ...) => same escape works.
			 */
			*q++ = DUK_ASC_BACKSLASH;
		}
		*q++ = (duk_uint8_t) c;

		c_prev = c;
	}

	DUK_BW_SETPTR_AND_COMPACT(thr, bw, q);
	(void) duk_buffer_to_string(thr, -1);  /* Safe if input is safe. */

	/* [ ... escaped_source ] */
}

/*
 *  Exposed regexp compilation primitive.
 *
 *  Sets up a regexp compilation context, and calls duk__parse_disjunction() to do the
 *  actual parsing.  Handles generation of the compiled regexp header and the
 *  "boilerplate" capture of the matching substring (save 0 and 1).  Also does some
 *  global level regexp checks after recursive compilation has finished.
 *
 *  An escaped version of the regexp source, suitable for use as a RegExp instance
 *  'source' property (see E5 Section 15.10.3), is also left on the stack.
 *
 *  Input stack:  [ pattern flags ]
 *  Output stack: [ bytecode escaped_source ]  (both as strings)
 */

DUK_INTERNAL void duk_regexp_compile(duk_hthread *thr) {
	duk_re_compiler_ctx re_ctx;
	duk_lexer_point lex_point;
	duk_hstring *h_pattern;
	duk_hstring *h_flags;
	duk__re_disjunction_info ign_disj;

	DUK_ASSERT(thr != NULL);

	/*
	 *  Args validation
	 */

	/* TypeError if fails */
	h_pattern = duk_require_hstring_notsymbol(thr, -2);
	h_flags = duk_require_hstring_notsymbol(thr, -1);

	/*
	 *  Create normalized 'source' property (E5 Section 15.10.3).
	 */

	/* [ ... pattern flags ] */

	duk__create_escaped_source(thr, -2);

	/* [ ... pattern flags escaped_source ] */

	/*
	 *  Init compilation context
	 */

	/* [ ... pattern flags escaped_source buffer ] */

	duk_memzero(&re_ctx, sizeof(re_ctx));
	DUK_LEXER_INITCTX(&re_ctx.lex);  /* duplicate zeroing, expect for (possible) NULL inits */
	re_ctx.thr = thr;
	re_ctx.lex.thr = thr;
	re_ctx.lex.input = DUK_HSTRING_GET_DATA(h_pattern);
	re_ctx.lex.input_length = DUK_HSTRING_GET_BYTELEN(h_pattern);
	re_ctx.lex.token_limit = DUK_RE_COMPILE_TOKEN_LIMIT;
	re_ctx.recursion_limit = DUK_USE_REGEXP_COMPILER_RECLIMIT;
	re_ctx.re_flags = duk__parse_regexp_flags(thr, h_flags);

	DUK_BW_INIT_PUSHBUF(thr, &re_ctx.bw, DUK__RE_INITIAL_BUFSIZE);

	DUK_DD(DUK_DDPRINT("regexp compiler ctx initialized, flags=0x%08lx, recursion_limit=%ld",
	                   (unsigned long) re_ctx.re_flags, (long) re_ctx.recursion_limit));

	/*
	 *  Init lexer
	 */

	lex_point.offset = 0;  /* expensive init, just want to fill window */
	lex_point.line = 1;
	DUK_LEXER_SETPOINT(&re_ctx.lex, &lex_point);

	/*
	 *  Compilation
	 */

	DUK_DD(DUK_DDPRINT("starting regexp compilation"));

	duk__append_reop(&re_ctx, DUK_REOP_SAVE);
	duk__append_7bit(&re_ctx, 0);
	duk__parse_disjunction(&re_ctx, 1 /*expect_eof*/, &ign_disj);
	duk__append_reop(&re_ctx, DUK_REOP_SAVE);
	duk__append_7bit(&re_ctx, 1);
	duk__append_reop(&re_ctx, DUK_REOP_MATCH);

	/*
	 *  Check for invalid backreferences; note that it is NOT an error
	 *  to back-reference a capture group which has not yet been introduced
	 *  in the pattern (as in /\1(foo)/); in fact, the backreference will
	 *  always match!  It IS an error to back-reference a capture group
	 *  which will never be introduced in the pattern.  Thus, we can check
	 *  for such references only after parsing is complete.
	 */

	if (re_ctx.highest_backref > re_ctx.captures) {
		DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_BACKREFS);
		DUK_WO_NORETURN(return;);
	}

	/*
	 *  Emit compiled regexp header: flags, ncaptures
	 *  (insertion order inverted on purpose)
	 */

	duk__insert_u32(&re_ctx, 0, (re_ctx.captures + 1) * 2);
	duk__insert_u32(&re_ctx, 0, re_ctx.re_flags);

	/* [ ... pattern flags escaped_source buffer ] */

	DUK_BW_COMPACT(thr, &re_ctx.bw);
	(void) duk_buffer_to_string(thr, -1);  /* Safe because flags is at most 7 bit. */

	/* [ ... pattern flags escaped_source bytecode ] */

	/*
	 *  Finalize stack
	 */

	duk_remove(thr, -4);     /* -> [ ... flags escaped_source bytecode ] */
	duk_remove(thr, -3);     /* -> [ ... escaped_source bytecode ] */

	DUK_DD(DUK_DDPRINT("regexp compilation successful, bytecode: %!T, escaped source: %!T",
	                   (duk_tval *) duk_get_tval(thr, -1), (duk_tval *) duk_get_tval(thr, -2)));
}

/*
 *  Create a RegExp instance (E5 Section 15.10.7).
 *
 *  Note: the output stack left by duk_regexp_compile() is directly compatible
 *  with the input here.
 *
 *  Input stack:  [ escaped_source bytecode ]  (both as strings)
 *  Output stack: [ RegExp ]
 */

DUK_INTERNAL void duk_regexp_create_instance(duk_hthread *thr) {
	duk_hobject *h;

	/* [ ... escaped_source bytecode ] */

	duk_push_object(thr);
	h = duk_known_hobject(thr, -1);
	duk_insert(thr, -3);

	/* [ ... regexp_object escaped_source bytecode ] */

	DUK_HOBJECT_SET_CLASS_NUMBER(h, DUK_HOBJECT_CLASS_REGEXP);
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, h, thr->builtins[DUK_BIDX_REGEXP_PROTOTYPE]);

	duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_INT_BYTECODE, DUK_PROPDESC_FLAGS_NONE);

	/* [ ... regexp_object escaped_source ] */

	/* In ES2015 .source, and the .global, .multiline, etc flags are
	 * inherited getters.  Store the escaped source as an internal
	 * property for the getter.
	 */

	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_INT_SOURCE, DUK_PROPDESC_FLAGS_NONE);

	/* [ ... regexp_object ] */

	duk_push_int(thr, 0);
	duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LAST_INDEX, DUK_PROPDESC_FLAGS_W);

	/* [ ... regexp_object ] */
}

#else  /* DUK_USE_REGEXP_SUPPORT */

/* regexp support disabled */

#endif  /* DUK_USE_REGEXP_SUPPORT */

/* automatic undefs */
#undef DUK__RE_BUFLEN
#undef DUK__RE_INITIAL_BUFSIZE
/*
 *  Regexp executor.
 *
 *  Safety: the ECMAScript executor should prevent user from reading and
 *  replacing regexp bytecode.  Even so, the executor must validate all
 *  memory accesses etc.  When an invalid access is detected (e.g. a 'save'
 *  opcode to invalid, unallocated index) it should fail with an internal
 *  error but not cause a segmentation fault.
 *
 *  Notes:
 *
 *    - Backtrack counts are limited to unsigned 32 bits but should
 *      technically be duk_size_t for strings longer than 4G chars.
 *      This also requires a regexp bytecode change.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_REGEXP_SUPPORT)

/*
 *  Helpers for UTF-8 handling
 *
 *  For bytecode readers the duk_uint32_t and duk_int32_t types are correct
 *  because they're used for more than just codepoints.
 */

DUK_LOCAL duk_uint32_t duk__bc_get_u32(duk_re_matcher_ctx *re_ctx, const duk_uint8_t **pc) {
	return (duk_uint32_t) duk_unicode_decode_xutf8_checked(re_ctx->thr, pc, re_ctx->bytecode, re_ctx->bytecode_end);
}

DUK_LOCAL duk_int32_t duk__bc_get_i32(duk_re_matcher_ctx *re_ctx, const duk_uint8_t **pc) {
	duk_uint32_t t;

	/* signed integer encoding needed to work with UTF-8 */
	t = (duk_uint32_t) duk_unicode_decode_xutf8_checked(re_ctx->thr, pc, re_ctx->bytecode, re_ctx->bytecode_end);
	if (t & 1) {
		return -((duk_int32_t) (t >> 1));
	} else {
		return (duk_int32_t) (t >> 1);
	}
}

DUK_LOCAL const duk_uint8_t *duk__utf8_backtrack(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end, duk_uint_fast32_t count) {
	const duk_uint8_t *p;

	/* Note: allow backtracking from p == ptr_end */
	p = *ptr;
	if (p < ptr_start || p > ptr_end) {
		goto fail;
	}

	while (count > 0) {
		for (;;) {
			p--;
			if (p < ptr_start) {
				goto fail;
			}
			if ((*p & 0xc0) != 0x80) {
				/* utf-8 continuation bytes have the form 10xx xxxx */
				break;
			}
		}
		count--;
	}
	*ptr = p;
	return p;

 fail:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return NULL;);
}

DUK_LOCAL const duk_uint8_t *duk__utf8_advance(duk_hthread *thr, const duk_uint8_t **ptr, const duk_uint8_t *ptr_start, const duk_uint8_t *ptr_end, duk_uint_fast32_t count) {
	const duk_uint8_t *p;

	p = *ptr;
	if (p < ptr_start || p >= ptr_end) {
		goto fail;
	}

	while (count > 0) {
		for (;;) {
			p++;

			/* Note: if encoding ends by hitting end of input, we don't check that
			 * the encoding is valid, we just assume it is.
			 */
			if (p >= ptr_end || ((*p & 0xc0) != 0x80)) {
				/* utf-8 continuation bytes have the form 10xx xxxx */
				break;
			}
		}
		count--;
	}

	*ptr = p;
	return p;

 fail:
	DUK_ERROR_INTERNAL(thr);
	DUK_WO_NORETURN(return NULL;);
}

/*
 *  Helpers for dealing with the input string
 */

/* Get a (possibly canonicalized) input character from current sp.  The input
 * itself is never modified, and captures always record non-canonicalized
 * characters even in case-insensitive matching.  Return <0 if out of input.
 */
DUK_LOCAL duk_codepoint_t duk__inp_get_cp(duk_re_matcher_ctx *re_ctx, const duk_uint8_t **sp) {
	duk_codepoint_t res;

	if (*sp >= re_ctx->input_end) {
		return -1;
	}
	res = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(re_ctx->thr, sp, re_ctx->input, re_ctx->input_end);
	if (re_ctx->re_flags & DUK_RE_FLAG_IGNORE_CASE) {
		res = duk_unicode_re_canonicalize_char(re_ctx->thr, res);
	}
	return res;
}

DUK_LOCAL const duk_uint8_t *duk__inp_backtrack(duk_re_matcher_ctx *re_ctx, const duk_uint8_t **sp, duk_uint_fast32_t count) {
	return duk__utf8_backtrack(re_ctx->thr, sp, re_ctx->input, re_ctx->input_end, count);
}

/* Backtrack utf-8 input and return a (possibly canonicalized) input character. */
DUK_LOCAL duk_codepoint_t duk__inp_get_prev_cp(duk_re_matcher_ctx *re_ctx, const duk_uint8_t *sp) {
	/* note: caller 'sp' is intentionally not updated here */
	(void) duk__inp_backtrack(re_ctx, &sp, (duk_uint_fast32_t) 1);
	return duk__inp_get_cp(re_ctx, &sp);
}

/*
 *  Regexp recursive matching function.
 *
 *  Returns 'sp' on successful match (points to character after last matched one),
 *  NULL otherwise.
 *
 *  The C recursion depth limit check is only performed in this function, this
 *  suffices because the function is present in all true recursion required by
 *  regexp execution.
 */

DUK_LOCAL const duk_uint8_t *duk__match_regexp(duk_re_matcher_ctx *re_ctx, const duk_uint8_t *pc, const duk_uint8_t *sp) {
	duk_native_stack_check(re_ctx->thr);
	if (re_ctx->recursion_depth >= re_ctx->recursion_limit) {
		DUK_ERROR_RANGE(re_ctx->thr, DUK_STR_REGEXP_EXECUTOR_RECURSION_LIMIT);
		DUK_WO_NORETURN(return NULL;);
	}
	re_ctx->recursion_depth++;

	for (;;) {
		duk_small_int_t op;

		if (re_ctx->steps_count >= re_ctx->steps_limit) {
			DUK_ERROR_RANGE(re_ctx->thr, DUK_STR_REGEXP_EXECUTOR_STEP_LIMIT);
			DUK_WO_NORETURN(return NULL;);
		}
		re_ctx->steps_count++;

		/* Opcodes are at most 7 bits now so they encode to one byte.  If this
		 * were not the case or 'pc' is invalid here (due to a bug etc) we'll
		 * still fail safely through the switch default case.
		 */
		DUK_ASSERT(pc[0] <= 0x7fU);
#if 0
		op = (duk_small_int_t) duk__bc_get_u32(re_ctx, &pc);
#endif
		op = *pc++;

		DUK_DDD(DUK_DDDPRINT("match: rec=%ld, steps=%ld, pc (after op)=%ld, sp=%ld, op=%ld",
		                     (long) re_ctx->recursion_depth,
		                     (long) re_ctx->steps_count,
		                     (long) (pc - re_ctx->bytecode),
		                     (long) (sp - re_ctx->input),
		                     (long) op));

		switch (op) {
		case DUK_REOP_MATCH: {
			goto match;
		}
		case DUK_REOP_CHAR: {
			/*
			 *  Byte-based matching would be possible for case-sensitive
			 *  matching but not for case-insensitive matching.  So, we
			 *  match by decoding the input and bytecode character normally.
			 *
			 *  Bytecode characters are assumed to be already canonicalized.
			 *  Input characters are canonicalized automatically by
			 *  duk__inp_get_cp() if necessary.
			 *
			 *  There is no opcode for matching multiple characters.  The
			 *  regexp compiler has trouble joining strings efficiently
			 *  during compilation.  See doc/regexp.rst for more discussion.
			 */
			duk_codepoint_t c1, c2;

			c1 = (duk_codepoint_t) duk__bc_get_u32(re_ctx, &pc);
			DUK_ASSERT(!(re_ctx->re_flags & DUK_RE_FLAG_IGNORE_CASE) ||
			           c1 == duk_unicode_re_canonicalize_char(re_ctx->thr, c1));  /* canonicalized by compiler */
			c2 = duk__inp_get_cp(re_ctx, &sp);
			/* No need to check for c2 < 0 (end of input): because c1 >= 0, it
			 * will fail the match below automatically and cause goto fail.
			 */
#if 0
			if (c2 < 0) {
				goto fail;
			}
#endif
			DUK_ASSERT(c1 >= 0);

			DUK_DDD(DUK_DDDPRINT("char match, c1=%ld, c2=%ld", (long) c1, (long) c2));
			if (c1 != c2) {
				goto fail;
			}
			break;
		}
		case DUK_REOP_PERIOD: {
			duk_codepoint_t c;

			c = duk__inp_get_cp(re_ctx, &sp);
			if (c < 0 || duk_unicode_is_line_terminator(c)) {
				/* E5 Sections 15.10.2.8, 7.3 */
				goto fail;
			}
			break;
		}
		case DUK_REOP_RANGES:
		case DUK_REOP_INVRANGES: {
			duk_uint32_t n;
			duk_codepoint_t c;
			duk_small_int_t match;

			n = duk__bc_get_u32(re_ctx, &pc);
			c = duk__inp_get_cp(re_ctx, &sp);
			if (c < 0) {
				goto fail;
			}

			match = 0;
			while (n) {
				duk_codepoint_t r1, r2;
				r1 = (duk_codepoint_t) duk__bc_get_u32(re_ctx, &pc);
				r2 = (duk_codepoint_t) duk__bc_get_u32(re_ctx, &pc);
				DUK_DDD(DUK_DDDPRINT("matching ranges/invranges, n=%ld, r1=%ld, r2=%ld, c=%ld",
				                     (long) n, (long) r1, (long) r2, (long) c));
				if (c >= r1 && c <= r2) {
					/* Note: don't bail out early, we must read all the ranges from
					 * bytecode.  Another option is to skip them efficiently after
					 * breaking out of here.  Prefer smallest code.
					 */
					match = 1;
				}
				n--;
			}

			if (op == DUK_REOP_RANGES) {
				if (!match) {
					goto fail;
				}
			} else {
				DUK_ASSERT(op == DUK_REOP_INVRANGES);
				if (match) {
					goto fail;
				}
			}
			break;
		}
		case DUK_REOP_ASSERT_START: {
			duk_codepoint_t c;

			if (sp <= re_ctx->input) {
				break;
			}
			if (!(re_ctx->re_flags & DUK_RE_FLAG_MULTILINE)) {
				goto fail;
			}
			c = duk__inp_get_prev_cp(re_ctx, sp);
			if (duk_unicode_is_line_terminator(c)) {
				/* E5 Sections 15.10.2.8, 7.3 */
				break;
			}
			goto fail;
		}
		case DUK_REOP_ASSERT_END: {
			duk_codepoint_t c;
			const duk_uint8_t *tmp_sp;

			tmp_sp = sp;
			c = duk__inp_get_cp(re_ctx, &tmp_sp);
			if (c < 0) {
				break;
			}
			if (!(re_ctx->re_flags & DUK_RE_FLAG_MULTILINE)) {
				goto fail;
			}
			if (duk_unicode_is_line_terminator(c)) {
				/* E5 Sections 15.10.2.8, 7.3 */
				break;
			}
			goto fail;
		}
		case DUK_REOP_ASSERT_WORD_BOUNDARY:
		case DUK_REOP_ASSERT_NOT_WORD_BOUNDARY: {
			/*
			 *  E5 Section 15.10.2.6.  The previous and current character
			 *  should -not- be canonicalized as they are now.  However,
			 *  canonicalization does not affect the result of IsWordChar()
			 *  (which depends on Unicode characters never canonicalizing
			 *  into ASCII characters) so this does not matter.
			 */
			duk_small_int_t w1, w2;

			if (sp <= re_ctx->input) {
				w1 = 0;  /* not a wordchar */
			} else {
				duk_codepoint_t c;
				c = duk__inp_get_prev_cp(re_ctx, sp);
				w1 = duk_unicode_re_is_wordchar(c);
			}
			if (sp >= re_ctx->input_end) {
				w2 = 0;  /* not a wordchar */
			} else {
				const duk_uint8_t *tmp_sp = sp;  /* dummy so sp won't get updated */
				duk_codepoint_t c;
				c = duk__inp_get_cp(re_ctx, &tmp_sp);
				w2 = duk_unicode_re_is_wordchar(c);
			}

			if (op == DUK_REOP_ASSERT_WORD_BOUNDARY) {
				if (w1 == w2) {
					goto fail;
				}
			} else {
				DUK_ASSERT(op == DUK_REOP_ASSERT_NOT_WORD_BOUNDARY);
				if (w1 != w2) {
					goto fail;
				}
			}
			break;
		}
		case DUK_REOP_JUMP: {
			duk_int32_t skip;

			skip = duk__bc_get_i32(re_ctx, &pc);
			pc += skip;
			break;
		}
		case DUK_REOP_SPLIT1: {
			/* split1: prefer direct execution (no jump) */
			const duk_uint8_t *sub_sp;
			duk_int32_t skip;

			skip = duk__bc_get_i32(re_ctx, &pc);
			sub_sp = duk__match_regexp(re_ctx, pc, sp);
			if (sub_sp) {
				sp = sub_sp;
				goto match;
			}
			pc += skip;
			break;
		}
		case DUK_REOP_SPLIT2: {
			/* split2: prefer jump execution (not direct) */
			const duk_uint8_t *sub_sp;
			duk_int32_t skip;

			skip = duk__bc_get_i32(re_ctx, &pc);
			sub_sp = duk__match_regexp(re_ctx, pc + skip, sp);
			if (sub_sp) {
				sp = sub_sp;
				goto match;
			}
			break;
		}
		case DUK_REOP_SQMINIMAL: {
			duk_uint32_t q, qmin, qmax;
			duk_int32_t skip;
			const duk_uint8_t *sub_sp;

			qmin = duk__bc_get_u32(re_ctx, &pc);
			qmax = duk__bc_get_u32(re_ctx, &pc);
			skip = duk__bc_get_i32(re_ctx, &pc);
			DUK_DDD(DUK_DDDPRINT("minimal quantifier, qmin=%lu, qmax=%lu, skip=%ld",
			                     (unsigned long) qmin, (unsigned long) qmax, (long) skip));

			q = 0;
			while (q <= qmax) {
				if (q >= qmin) {
					sub_sp = duk__match_regexp(re_ctx, pc + skip, sp);
					if (sub_sp) {
						sp = sub_sp;
						goto match;
					}
				}
				sub_sp = duk__match_regexp(re_ctx, pc, sp);
				if (!sub_sp) {
					break;
				}
				sp = sub_sp;
				q++;
			}
			goto fail;
		}
		case DUK_REOP_SQGREEDY: {
			duk_uint32_t q, qmin, qmax, atomlen;
			duk_int32_t skip;
			const duk_uint8_t *sub_sp;

			qmin = duk__bc_get_u32(re_ctx, &pc);
			qmax = duk__bc_get_u32(re_ctx, &pc);
			atomlen = duk__bc_get_u32(re_ctx, &pc);
			skip = duk__bc_get_i32(re_ctx, &pc);
			DUK_DDD(DUK_DDDPRINT("greedy quantifier, qmin=%lu, qmax=%lu, atomlen=%lu, skip=%ld",
			                     (unsigned long) qmin, (unsigned long) qmax, (unsigned long) atomlen, (long) skip));

			q = 0;
			while (q < qmax) {
				sub_sp = duk__match_regexp(re_ctx, pc, sp);
				if (!sub_sp) {
					break;
				}
				sp = sub_sp;
				q++;
			}
			while (q >= qmin) {
				sub_sp = duk__match_regexp(re_ctx, pc + skip, sp);
				if (sub_sp) {
					sp = sub_sp;
					goto match;
				}
				if (q == qmin) {
					break;
				}

				/* Note: if atom were to contain e.g. captures, we would need to
				 * re-match the atom to get correct captures.  Simply quantifiers
				 * do not allow captures in their atom now, so this is not an issue.
				 */

				DUK_DDD(DUK_DDDPRINT("greedy quantifier, backtrack %ld characters (atomlen)",
				                     (long) atomlen));
				sp = duk__inp_backtrack(re_ctx, &sp, (duk_uint_fast32_t) atomlen);
				q--;
			}
			goto fail;
		}
		case DUK_REOP_SAVE: {
			duk_uint32_t idx;
			const duk_uint8_t *old;
			const duk_uint8_t *sub_sp;

			idx = duk__bc_get_u32(re_ctx, &pc);
			if (idx >= re_ctx->nsaved) {
				/* idx is unsigned, < 0 check is not necessary */
				DUK_D(DUK_DPRINT("internal error, regexp save index insane: idx=%ld", (long) idx));
				goto internal_error;
			}
			old = re_ctx->saved[idx];
			re_ctx->saved[idx] = sp;
			sub_sp = duk__match_regexp(re_ctx, pc, sp);
			if (sub_sp) {
				sp = sub_sp;
				goto match;
			}
			re_ctx->saved[idx] = old;
			goto fail;
		}
		case DUK_REOP_WIPERANGE: {
			/* Wipe capture range and save old values for backtracking.
			 *
			 * XXX: this typically happens with a relatively small idx_count.
			 * It might be useful to handle cases where the count is small
			 * (say <= 8) by saving the values in stack instead.  This would
			 * reduce memory churn and improve performance, at the cost of a
			 * slightly higher code footprint.
			 */
			duk_uint32_t idx_start, idx_count;
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
			duk_uint32_t idx_end, idx;
#endif
			duk_uint8_t **range_save;
			const duk_uint8_t *sub_sp;

			idx_start = duk__bc_get_u32(re_ctx, &pc);
			idx_count = duk__bc_get_u32(re_ctx, &pc);
			DUK_DDD(DUK_DDDPRINT("wipe saved range: start=%ld, count=%ld -> [%ld,%ld] (captures [%ld,%ld])",
			                     (long) idx_start, (long) idx_count,
			                     (long) idx_start, (long) (idx_start + idx_count - 1),
			                     (long) (idx_start / 2), (long) ((idx_start + idx_count - 1) / 2)));
			if (idx_start + idx_count > re_ctx->nsaved || idx_count == 0) {
				/* idx is unsigned, < 0 check is not necessary */
				DUK_D(DUK_DPRINT("internal error, regexp wipe indices insane: idx_start=%ld, idx_count=%ld",
				                 (long) idx_start, (long) idx_count));
				goto internal_error;
			}
			DUK_ASSERT(idx_count > 0);

			duk_require_stack(re_ctx->thr, 1);
			range_save = (duk_uint8_t **) duk_push_fixed_buffer_nozero(re_ctx->thr,
			                                                           sizeof(duk_uint8_t *) * idx_count);
			DUK_ASSERT(range_save != NULL);
			duk_memcpy(range_save, re_ctx->saved + idx_start, sizeof(duk_uint8_t *) * idx_count);
#if defined(DUK_USE_EXPLICIT_NULL_INIT)
			idx_end = idx_start + idx_count;
			for (idx = idx_start; idx < idx_end; idx++) {
				re_ctx->saved[idx] = NULL;
			}
#else
			duk_memzero((void *) (re_ctx->saved + idx_start), sizeof(duk_uint8_t *) * idx_count);
#endif

			sub_sp = duk__match_regexp(re_ctx, pc, sp);
			if (sub_sp) {
				/* match: keep wiped/resaved values */
				DUK_DDD(DUK_DDDPRINT("match: keep wiped/resaved values [%ld,%ld] (captures [%ld,%ld])",
				                     (long) idx_start, (long) (idx_start + idx_count - 1),
			                             (long) (idx_start / 2), (long) ((idx_start + idx_count - 1) / 2)));
				duk_pop_unsafe(re_ctx->thr);
				sp = sub_sp;
				goto match;
			}

			/* fail: restore saves */
			DUK_DDD(DUK_DDDPRINT("fail: restore wiped/resaved values [%ld,%ld] (captures [%ld,%ld])",
			                     (long) idx_start, (long) (idx_start + idx_count - 1),
			                     (long) (idx_start / 2), (long) ((idx_start + idx_count - 1) / 2)));
			duk_memcpy((void *) (re_ctx->saved + idx_start),
			           (const void *) range_save,
			           sizeof(duk_uint8_t *) * idx_count);
			duk_pop_unsafe(re_ctx->thr);
			goto fail;
		}
		case DUK_REOP_LOOKPOS:
		case DUK_REOP_LOOKNEG: {
			/*
			 *  Needs a save of multiple saved[] entries depending on what range
			 *  may be overwritten.  Because the regexp parser does no such analysis,
			 *  we currently save the entire saved array here.  Lookaheads are thus
			 *  a bit expensive.  Note that the saved array is not needed for just
			 *  the lookahead sub-match, but for the matching of the entire sequel.
			 *
			 *  The temporary save buffer is pushed on to the valstack to handle
			 *  errors correctly.  Each lookahead causes a C recursion and pushes
			 *  more stuff on the value stack.  If the C recursion limit is less
			 *  than the value stack slack, there is no need to check the stack.
			 *  We do so regardless, just in case.
			 */

			duk_int32_t skip;
			duk_uint8_t **full_save;
			const duk_uint8_t *sub_sp;

			DUK_ASSERT(re_ctx->nsaved > 0);

			duk_require_stack(re_ctx->thr, 1);
			full_save = (duk_uint8_t **) duk_push_fixed_buffer_nozero(re_ctx->thr,
			                                                          sizeof(duk_uint8_t *) * re_ctx->nsaved);
			DUK_ASSERT(full_save != NULL);
			duk_memcpy(full_save, re_ctx->saved, sizeof(duk_uint8_t *) * re_ctx->nsaved);

			skip = duk__bc_get_i32(re_ctx, &pc);
			sub_sp = duk__match_regexp(re_ctx, pc, sp);
			if (op == DUK_REOP_LOOKPOS) {
				if (!sub_sp) {
					goto lookahead_fail;
				}
			} else {
				if (sub_sp) {
					goto lookahead_fail;
				}
			}
			sub_sp = duk__match_regexp(re_ctx, pc + skip, sp);
			if (sub_sp) {
				/* match: keep saves */
				duk_pop_unsafe(re_ctx->thr);
				sp = sub_sp;
				goto match;
			}

			/* fall through */

		 lookahead_fail:
			/* fail: restore saves */
			duk_memcpy((void *) re_ctx->saved,
			           (const void *) full_save,
			           sizeof(duk_uint8_t *) * re_ctx->nsaved);
			duk_pop_unsafe(re_ctx->thr);
			goto fail;
		}
		case DUK_REOP_BACKREFERENCE: {
			/*
			 *  Byte matching for back-references would be OK in case-
			 *  sensitive matching.  In case-insensitive matching we need
			 *  to canonicalize characters, so back-reference matching needs
			 *  to be done with codepoints instead.  So, we just decode
			 *  everything normally here, too.
			 *
			 *  Note: back-reference index which is 0 or higher than
			 *  NCapturingParens (= number of capturing parens in the
			 *  -entire- regexp) is a compile time error.  However, a
			 *  backreference referring to a valid capture which has
			 *  not matched anything always succeeds!  See E5 Section
			 *  15.10.2.9, step 5, sub-step 3.
			 */
			duk_uint32_t idx;
			const duk_uint8_t *p;

			idx = duk__bc_get_u32(re_ctx, &pc);
			idx = idx << 1;  /* backref n -> saved indices [n*2, n*2+1] */
			if (idx < 2 || idx + 1 >= re_ctx->nsaved) {
				/* regexp compiler should catch these */
				DUK_D(DUK_DPRINT("internal error, backreference index insane"));
				goto internal_error;
			}
			if (!re_ctx->saved[idx] || !re_ctx->saved[idx+1]) {
				/* capture is 'undefined', always matches! */
				DUK_DDD(DUK_DDDPRINT("backreference: saved[%ld,%ld] not complete, always match",
				                     (long) idx, (long) (idx + 1)));
				break;
			}
			DUK_DDD(DUK_DDDPRINT("backreference: match saved[%ld,%ld]", (long) idx, (long) (idx + 1)));

			p = re_ctx->saved[idx];
			while (p < re_ctx->saved[idx+1]) {
				duk_codepoint_t c1, c2;

				/* Note: not necessary to check p against re_ctx->input_end:
				 * the memory access is checked by duk__inp_get_cp(), while
				 * valid compiled regexps cannot write a saved[] entry
				 * which points to outside the string.
				 */
				c1 = duk__inp_get_cp(re_ctx, &p);
				DUK_ASSERT(c1 >= 0);
				c2 = duk__inp_get_cp(re_ctx, &sp);
				/* No need for an explicit c2 < 0 check: because c1 >= 0,
				 * the comparison will always fail if c2 < 0.
				 */
#if 0
				if (c2 < 0) {
					goto fail;
				}
#endif
				if (c1 != c2) {
					goto fail;
				}
			}
			break;
		}
		default: {
			DUK_D(DUK_DPRINT("internal error, regexp opcode error: %ld", (long) op));
			goto internal_error;
		}
		}
	}

 match:
	re_ctx->recursion_depth--;
	return sp;

 fail:
	re_ctx->recursion_depth--;
	return NULL;

 internal_error:
	DUK_ERROR_INTERNAL(re_ctx->thr);
	DUK_WO_NORETURN(return NULL;);
}

/*
 *  Exposed matcher function which provides the semantics of RegExp.prototype.exec().
 *
 *  RegExp.prototype.test() has the same semantics as exec() but does not return the
 *  result object (which contains the matching string and capture groups).  Currently
 *  there is no separate test() helper, so a temporary result object is created and
 *  discarded if test() is needed.  This is intentional, to save code space.
 *
 *  Input stack:  [ ... re_obj input ]
 *  Output stack: [ ... result ]
 */

DUK_LOCAL void duk__regexp_match_helper(duk_hthread *thr, duk_small_int_t force_global) {
	duk_re_matcher_ctx re_ctx;
	duk_hobject *h_regexp;
	duk_hstring *h_bytecode;
	duk_hstring *h_input;
	duk_uint8_t *p_buf;
	const duk_uint8_t *pc;
	const duk_uint8_t *sp;
	duk_small_int_t match = 0;
	duk_small_int_t global;
	duk_uint_fast32_t i;
	double d;
	duk_uint32_t char_offset;

	DUK_ASSERT(thr != NULL);

	DUK_DD(DUK_DDPRINT("regexp match: regexp=%!T, input=%!T",
	                   (duk_tval *) duk_get_tval(thr, -2),
	                   (duk_tval *) duk_get_tval(thr, -1)));

	/*
	 *  Regexp instance check, bytecode check, input coercion.
	 *
	 *  See E5 Section 15.10.6.
	 */

	/* TypeError if wrong; class check, see E5 Section 15.10.6 */
	h_regexp = duk_require_hobject_with_class(thr, -2, DUK_HOBJECT_CLASS_REGEXP);
	DUK_ASSERT(h_regexp != NULL);
	DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(h_regexp) == DUK_HOBJECT_CLASS_REGEXP);
	DUK_UNREF(h_regexp);

	h_input = duk_to_hstring(thr, -1);
	DUK_ASSERT(h_input != NULL);

	duk_xget_owndataprop_stridx_short(thr, -2, DUK_STRIDX_INT_BYTECODE);  /* [ ... re_obj input ] -> [ ... re_obj input bc ] */
	h_bytecode = duk_require_hstring(thr, -1);  /* no regexp instance should exist without a non-configurable bytecode property */
	DUK_ASSERT(h_bytecode != NULL);

	/*
	 *  Basic context initialization.
	 *
	 *  Some init values are read from the bytecode header
	 *  whose format is (UTF-8 codepoints):
	 *
	 *    uint   flags
	 *    uint   nsaved (even, 2n+2 where n = num captures)
	 */

	/* [ ... re_obj input bc ] */

	duk_memzero(&re_ctx, sizeof(re_ctx));

	re_ctx.thr = thr;
	re_ctx.input = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
	re_ctx.input_end = re_ctx.input + DUK_HSTRING_GET_BYTELEN(h_input);
	re_ctx.bytecode = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_bytecode);
	re_ctx.bytecode_end = re_ctx.bytecode + DUK_HSTRING_GET_BYTELEN(h_bytecode);
	re_ctx.saved = NULL;
	re_ctx.recursion_limit = DUK_USE_REGEXP_EXECUTOR_RECLIMIT;
	re_ctx.steps_limit = DUK_RE_EXECUTE_STEPS_LIMIT;

	/* read header */
	pc = re_ctx.bytecode;
	re_ctx.re_flags = duk__bc_get_u32(&re_ctx, &pc);
	re_ctx.nsaved = duk__bc_get_u32(&re_ctx, &pc);
	re_ctx.bytecode = pc;

	DUK_ASSERT(DUK_RE_FLAG_GLOBAL < 0x10000UL);  /* must fit into duk_small_int_t */
	global = (duk_small_int_t) (force_global | (duk_small_int_t) (re_ctx.re_flags & DUK_RE_FLAG_GLOBAL));

	DUK_ASSERT(re_ctx.nsaved >= 2);
	DUK_ASSERT((re_ctx.nsaved % 2) == 0);

	p_buf = (duk_uint8_t *) duk_push_fixed_buffer(thr, sizeof(duk_uint8_t *) * re_ctx.nsaved);  /* rely on zeroing */
	DUK_UNREF(p_buf);
	re_ctx.saved = (const duk_uint8_t **) duk_get_buffer(thr, -1, NULL);
	DUK_ASSERT(re_ctx.saved != NULL);

	/* [ ... re_obj input bc saved_buf ] */

#if defined(DUK_USE_EXPLICIT_NULL_INIT)
	for (i = 0; i < re_ctx.nsaved; i++) {
		re_ctx.saved[i] = (duk_uint8_t *) NULL;
	}
#elif defined(DUK_USE_ZERO_BUFFER_DATA)
	/* buffer is automatically zeroed */
#else
	duk_memzero((void *) p_buf, sizeof(duk_uint8_t *) * re_ctx.nsaved);
#endif

	DUK_DDD(DUK_DDDPRINT("regexp ctx initialized, flags=0x%08lx, nsaved=%ld, recursion_limit=%ld, steps_limit=%ld",
	                     (unsigned long) re_ctx.re_flags, (long) re_ctx.nsaved, (long) re_ctx.recursion_limit,
	                     (long) re_ctx.steps_limit));

	/*
	 *  Get starting character offset for match, and initialize 'sp' based on it.
	 *
	 *  Note: lastIndex is non-configurable so it must be present (we check the
	 *  internal class of the object above, so we know it is).  User code can set
	 *  its value to an arbitrary (garbage) value though; E5 requires that lastIndex
	 *  be coerced to a number before using.  The code below works even if the
	 *  property is missing: the value will then be coerced to zero.
	 *
	 *  Note: lastIndex may be outside Uint32 range even after ToInteger() coercion.
	 *  For instance, ToInteger(+Infinity) = +Infinity.  We track the match offset
	 *  as an integer, but pre-check it to be inside the 32-bit range before the loop.
	 *  If not, the check in E5 Section 15.10.6.2, step 9.a applies.
	 */

	/* XXX: lastIndex handling produces a lot of asm */

	/* [ ... re_obj input bc saved_buf ] */

	duk_get_prop_stridx_short(thr, -4, DUK_STRIDX_LAST_INDEX);  /* -> [ ... re_obj input bc saved_buf lastIndex ] */
	(void) duk_to_int(thr, -1);  /* ToInteger(lastIndex) */
	d = duk_get_number(thr, -1);  /* integer, but may be +/- Infinite, +/- zero (not NaN, though) */
	duk_pop_nodecref_unsafe(thr);

	if (global) {
		if (d < 0.0 || d > (double) DUK_HSTRING_GET_CHARLEN(h_input)) {
			/* match fail */
			char_offset = 0;   /* not really necessary */
			DUK_ASSERT(match == 0);
			goto match_over;
		}
		char_offset = (duk_uint32_t) d;
	} else {
		/* lastIndex must be ignored for non-global regexps, but get the
		 * value for (theoretical) side effects.  No side effects can
		 * really occur, because lastIndex is a normal property and is
		 * always non-configurable for RegExp instances.
		 */
		char_offset = (duk_uint32_t) 0;
	}

	DUK_ASSERT(char_offset <= DUK_HSTRING_GET_CHARLEN(h_input));
	sp = re_ctx.input + duk_heap_strcache_offset_char2byte(thr, h_input, char_offset);

	/*
	 *  Match loop.
	 *
	 *  Try matching at different offsets until match found or input exhausted.
	 */

	/* [ ... re_obj input bc saved_buf ] */

	DUK_ASSERT(match == 0);

	for (;;) {
		/* char offset in [0, h_input->clen] (both ends inclusive), checked before entry */
		DUK_ASSERT_DISABLE(char_offset >= 0);
		DUK_ASSERT(char_offset <= DUK_HSTRING_GET_CHARLEN(h_input));

		/* Note: re_ctx.steps is intentionally not reset, it applies to the entire unanchored match */
		DUK_ASSERT(re_ctx.recursion_depth == 0);

		DUK_DDD(DUK_DDDPRINT("attempt match at char offset %ld; %p [%p,%p]",
		                     (long) char_offset, (const void *) sp,
		                     (const void *) re_ctx.input, (const void *) re_ctx.input_end));

		/*
		 *  Note:
		 *
		 *    - duk__match_regexp() is required not to longjmp() in ordinary "non-match"
		 *      conditions; a longjmp() will terminate the entire matching process.
		 *
		 *    - Clearing saved[] is not necessary because backtracking does it
		 *
		 *    - Backtracking also rewinds re_ctx.recursion back to zero, unless an
		 *      internal/limit error occurs (which causes a longjmp())
		 *
		 *    - If we supported anchored matches, we would break out here
		 *      unconditionally; however, ECMAScript regexps don't have anchored
		 *      matches.  It might make sense to implement a fast bail-out if
		 *      the regexp begins with '^' and sp is not 0: currently we'll just
		 *      run through the entire input string, trivially failing the match
		 *      at every non-zero offset.
		 */

		if (duk__match_regexp(&re_ctx, re_ctx.bytecode, sp) != NULL) {
			DUK_DDD(DUK_DDDPRINT("match at offset %ld", (long) char_offset));
			match = 1;
			break;
		}

		/* advance by one character (code point) and one char_offset */
		char_offset++;
		if (char_offset > DUK_HSTRING_GET_CHARLEN(h_input)) {
			/*
			 *  Note:
			 *
			 *    - Intentionally attempt (empty) match at char_offset == k_input->clen
			 *
			 *    - Negative char_offsets have been eliminated and char_offset is duk_uint32_t
			 *      -> no need or use for a negative check
			 */

			DUK_DDD(DUK_DDDPRINT("no match after trying all sp offsets"));
			break;
		}

		/* avoid calling at end of input, will DUK_ERROR (above check suffices to avoid this) */
		(void) duk__utf8_advance(thr, &sp, re_ctx.input, re_ctx.input_end, (duk_uint_fast32_t) 1);
	}

 match_over:

	/*
	 *  Matching complete, create result array or return a 'null'.  Update lastIndex
	 *  if necessary.  See E5 Section 15.10.6.2.
	 *
	 *  Because lastIndex is a character (not byte) offset, we need the character
	 *  length of the match which we conveniently get as a side effect of interning
	 *  the matching substring (0th index of result array).
	 *
	 *  saved[0]         start pointer (~ byte offset) of current match
	 *  saved[1]         end pointer (~ byte offset) of current match (exclusive)
	 *  char_offset      start character offset of current match (-> .index of result)
	 *  char_end_offset  end character offset (computed below)
	 */

	/* [ ... re_obj input bc saved_buf ] */

	if (match) {
#if defined(DUK_USE_ASSERTIONS)
		duk_hobject *h_res;
#endif
		duk_uint32_t char_end_offset = 0;

		DUK_DDD(DUK_DDDPRINT("regexp matches at char_offset %ld", (long) char_offset));

		DUK_ASSERT(re_ctx.nsaved >= 2);        /* must have start and end */
		DUK_ASSERT((re_ctx.nsaved % 2) == 0);  /* and even number */

		/* XXX: Array size is known before and (2 * re_ctx.nsaved) but not taken
		 * advantage of now.  The array is not compacted either, as regexp match
		 * objects are usually short lived.
		 */

		duk_push_array(thr);

#if defined(DUK_USE_ASSERTIONS)
		h_res = duk_require_hobject(thr, -1);
		DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(h_res));
		DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_ARRAY(h_res));
		DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(h_res) == DUK_HOBJECT_CLASS_ARRAY);
#endif

		/* [ ... re_obj input bc saved_buf res_obj ] */

		duk_push_u32(thr, char_offset);
		duk_xdef_prop_stridx_short_wec(thr, -2, DUK_STRIDX_INDEX);

		duk_dup_m4(thr);
		duk_xdef_prop_stridx_short_wec(thr, -2, DUK_STRIDX_INPUT);

		for (i = 0; i < re_ctx.nsaved; i += 2) {
			/* Captures which are undefined have NULL pointers and are returned
			 * as 'undefined'.  The same is done when saved[] pointers are insane
			 * (this should, of course, never happen in practice).
			 */
			if (re_ctx.saved[i] && re_ctx.saved[i + 1] && re_ctx.saved[i + 1] >= re_ctx.saved[i]) {
				duk_push_lstring(thr,
				                 (const char *) re_ctx.saved[i],
				                 (duk_size_t) (re_ctx.saved[i+1] - re_ctx.saved[i]));
				if (i == 0) {
					/* Assumes that saved[0] and saved[1] are always
					 * set by regexp bytecode (if not, char_end_offset
					 * will be zero).  Also assumes clen reflects the
					 * correct char length.
					 */
					char_end_offset = char_offset + (duk_uint32_t) duk_get_length(thr, -1);  /* add charlen */
				}
			} else {
				duk_push_undefined(thr);
			}

			/* [ ... re_obj input bc saved_buf res_obj val ] */
			duk_put_prop_index(thr, -2, (duk_uarridx_t) (i / 2));
		}

		/* [ ... re_obj input bc saved_buf res_obj ] */

		/* NB: 'length' property is automatically updated by the array setup loop */

		if (global) {
			/* global regexp: lastIndex updated on match */
			duk_push_u32(thr, char_end_offset);
			duk_put_prop_stridx_short(thr, -6, DUK_STRIDX_LAST_INDEX);
		} else {
			/* non-global regexp: lastIndex never updated on match */
			;
		}
	} else {
		/*
		 *  No match, E5 Section 15.10.6.2, step 9.a.i - 9.a.ii apply, regardless
		 *  of 'global' flag of the RegExp.  In particular, if lastIndex is invalid
		 *  initially, it is reset to zero.
		 */

		DUK_DDD(DUK_DDDPRINT("regexp does not match"));

		duk_push_null(thr);

		/* [ ... re_obj input bc saved_buf res_obj ] */

		duk_push_int(thr, 0);
		duk_put_prop_stridx_short(thr, -6, DUK_STRIDX_LAST_INDEX);
	}

	/* [ ... re_obj input bc saved_buf res_obj ] */

	duk_insert(thr, -5);

	/* [ ... res_obj re_obj input bc saved_buf ] */

	duk_pop_n_unsafe(thr, 4);

	/* [ ... res_obj ] */

	/* XXX: these last tricks are unnecessary if the function is made
	 * a genuine native function.
	 */
}

DUK_INTERNAL void duk_regexp_match(duk_hthread *thr) {
	duk__regexp_match_helper(thr, 0 /*force_global*/);
}

/* This variant is needed by String.prototype.split(); it needs to perform
 * global-style matching on a cloned RegExp which is potentially non-global.
 */
DUK_INTERNAL void duk_regexp_match_force_global(duk_hthread *thr) {
	duk__regexp_match_helper(thr, 1 /*force_global*/);
}

#else  /* DUK_USE_REGEXP_SUPPORT */

/* regexp support disabled */

#endif  /* DUK_USE_REGEXP_SUPPORT */
/*
 *  Self tests to ensure execution environment is sane.  Intended to catch
 *  compiler/platform problems which cannot be detected at compile time.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_SELF_TESTS)

/*
 *  Unions and structs for self tests
 */

typedef union {
	double d;
	duk_uint8_t x[8];
} duk__test_double_union;

/* Self test failed.  Expects a local variable 'error_count' to exist. */
#define DUK__FAILED(msg)  do { \
		DUK_D(DUK_DPRINT("self test failed: " #msg " at " DUK_FILE_MACRO ":" DUK_MACRO_STRINGIFY(DUK_LINE_MACRO))); \
		error_count++; \
	} while (0)

#define DUK__DBLUNION_CMP_TRUE(a,b)  do { \
		if (duk_memcmp((const void *) (a), (const void *) (b), sizeof(duk__test_double_union)) != 0) { \
			DUK__FAILED("double union compares false (expected true)"); \
		} \
	} while (0)

#define DUK__DBLUNION_CMP_FALSE(a,b)  do { \
		if (duk_memcmp((const void *) (a), (const void *) (b), sizeof(duk__test_double_union)) == 0) { \
			DUK__FAILED("double union compares true (expected false)"); \
		} \
	} while (0)

typedef union {
	duk_uint32_t i;
	duk_uint8_t x[8];
} duk__test_u32_union;

#if defined(DUK_USE_INTEGER_LE)
#define DUK__U32_INIT(u, a, b, c, d) do { \
		(u)->x[0] = (d); (u)->x[1] = (c); (u)->x[2] = (b); (u)->x[3] = (a); \
	} while (0)
#elif defined(DUK_USE_INTEGER_ME)
#error integer mixed endian not supported now
#elif defined(DUK_USE_INTEGER_BE)
#define DUK__U32_INIT(u, a, b, c, d) do { \
		(u)->x[0] = (a); (u)->x[1] = (b); (u)->x[2] = (c); (u)->x[3] = (d); \
	} while (0)
#else
#error unknown integer endianness
#endif

#if defined(DUK_USE_DOUBLE_LE)
#define DUK__DOUBLE_INIT(u, a, b, c, d, e, f, g, h) do { \
		(u)->x[0] = (h); (u)->x[1] = (g); (u)->x[2] = (f); (u)->x[3] = (e); \
		(u)->x[4] = (d); (u)->x[5] = (c); (u)->x[6] = (b); (u)->x[7] = (a); \
	} while (0)
#define DUK__DOUBLE_COMPARE(u, a, b, c, d, e, f, g, h) \
	((u)->x[0] == (h) && (u)->x[1] == (g) && (u)->x[2] == (f) && (u)->x[3] == (e) && \
	 (u)->x[4] == (d) && (u)->x[5] == (c) && (u)->x[6] == (b) && (u)->x[7] == (a))
#elif defined(DUK_USE_DOUBLE_ME)
#define DUK__DOUBLE_INIT(u, a, b, c, d, e, f, g, h) do { \
		(u)->x[0] = (d); (u)->x[1] = (c); (u)->x[2] = (b); (u)->x[3] = (a); \
		(u)->x[4] = (h); (u)->x[5] = (g); (u)->x[6] = (f); (u)->x[7] = (e); \
	} while (0)
#define DUK__DOUBLE_COMPARE(u, a, b, c, d, e, f, g, h) \
	((u)->x[0] == (d) && (u)->x[1] == (c) && (u)->x[2] == (b) && (u)->x[3] == (a) && \
	 (u)->x[4] == (h) && (u)->x[5] == (g) && (u)->x[6] == (f) && (u)->x[7] == (e))
#elif defined(DUK_USE_DOUBLE_BE)
#define DUK__DOUBLE_INIT(u, a, b, c, d, e, f, g, h) do { \
		(u)->x[0] = (a); (u)->x[1] = (b); (u)->x[2] = (c); (u)->x[3] = (d); \
		(u)->x[4] = (e); (u)->x[5] = (f); (u)->x[6] = (g); (u)->x[7] = (h); \
	} while (0)
#define DUK__DOUBLE_COMPARE(u, a, b, c, d, e, f, g, h) \
	((u)->x[0] == (a) && (u)->x[1] == (b) && (u)->x[2] == (c) && (u)->x[3] == (d) && \
	 (u)->x[4] == (e) && (u)->x[5] == (f) && (u)->x[6] == (g) && (u)->x[7] == (h))
#else
#error unknown double endianness
#endif

/*
 *  Various sanity checks for typing
 */

DUK_LOCAL duk_uint_t duk__selftest_types(void) {
	duk_uint_t error_count = 0;

	if (!(sizeof(duk_int8_t) == 1 &&
	      sizeof(duk_uint8_t) == 1 &&
	      sizeof(duk_int16_t) == 2 &&
	      sizeof(duk_uint16_t) == 2 &&
	      sizeof(duk_int32_t) == 4 &&
	      sizeof(duk_uint32_t) == 4)) {
		DUK__FAILED("duk_(u)int{8,16,32}_t size");
	}
#if defined(DUK_USE_64BIT_OPS)
	if (!(sizeof(duk_int64_t) == 8 &&
	      sizeof(duk_uint64_t) == 8)) {
		DUK__FAILED("duk_(u)int64_t size");
	}
#endif

	if (!(sizeof(duk_size_t) >= sizeof(duk_uint_t))) {
		/* Some internal code now assumes that all duk_uint_t values
		 * can be expressed with a duk_size_t.
		 */
		DUK__FAILED("duk_size_t is smaller than duk_uint_t");
	}
	if (!(sizeof(duk_int_t) >= 4)) {
		DUK__FAILED("duk_int_t is not 32 bits");
	}

	return error_count;
}

/*
 *  Packed tval sanity
 */

DUK_LOCAL duk_uint_t duk__selftest_packed_tval(void) {
	duk_uint_t error_count = 0;

#if defined(DUK_USE_PACKED_TVAL)
	if (sizeof(void *) > 4) {
		DUK__FAILED("packed duk_tval in use but sizeof(void *) > 4");
	}
#endif

	return error_count;
}

/*
 *  Two's complement arithmetic.
 */

DUK_LOCAL duk_uint_t duk__selftest_twos_complement(void) {
	duk_uint_t error_count = 0;
	volatile int test;
	test = -1;

	/* Note that byte order doesn't affect this test: all bytes in
	 * 'test' will be 0xFF for two's complement.
	 */
	if (((volatile duk_uint8_t *) &test)[0] != (duk_uint8_t) 0xff) {
		DUK__FAILED("two's complement arithmetic");
	}

	return error_count;
}

/*
 *  Byte order.  Important to self check, because on some exotic platforms
 *  there is no actual detection but rather assumption based on platform
 *  defines.
 */

DUK_LOCAL duk_uint_t duk__selftest_byte_order(void) {
	duk_uint_t error_count = 0;
	duk__test_u32_union u1;
	duk__test_double_union u2;

	/*
	 *  >>> struct.pack('>d', 102030405060).encode('hex')
	 *  '4237c17c6dc40000'
	 */

	DUK__U32_INIT(&u1, 0xde, 0xad, 0xbe, 0xef);
	DUK__DOUBLE_INIT(&u2, 0x42, 0x37, 0xc1, 0x7c, 0x6d, 0xc4, 0x00, 0x00);

	if (u1.i != (duk_uint32_t) 0xdeadbeefUL) {
		DUK__FAILED("duk_uint32_t byte order");
	}

	if (!duk_double_equals(u2.d, 102030405060.0)) {
		DUK__FAILED("double byte order");
	}

	return error_count;
}

/*
 *  DUK_BSWAP macros
 */

DUK_LOCAL duk_uint_t duk__selftest_bswap_macros(void) {
	duk_uint_t error_count = 0;
	volatile duk_uint32_t x32_input, x32_output;
	duk_uint32_t x32;
	volatile duk_uint16_t x16_input, x16_output;
	duk_uint16_t x16;
	duk_double_union du;
	duk_double_t du_diff;
#if defined(DUK_BSWAP64)
	volatile duk_uint64_t x64_input, x64_output;
	duk_uint64_t x64;
#endif

	/* Cover both compile time and runtime bswap operations, as these
	 * may have different bugs.
	 */

	x16_input = 0xbeefUL;
	x16 = x16_input;
	x16 = DUK_BSWAP16(x16);
	x16_output = x16;
	if (x16_output != (duk_uint16_t) 0xefbeUL) {
		DUK__FAILED("DUK_BSWAP16");
	}

	x16 = 0xbeefUL;
	x16 = DUK_BSWAP16(x16);
	if (x16 != (duk_uint16_t) 0xefbeUL) {
		DUK__FAILED("DUK_BSWAP16");
	}

	x32_input = 0xdeadbeefUL;
	x32 = x32_input;
	x32 = DUK_BSWAP32(x32);
	x32_output = x32;
	if (x32_output != (duk_uint32_t) 0xefbeaddeUL) {
		DUK__FAILED("DUK_BSWAP32");
	}

	x32 = 0xdeadbeefUL;
	x32 = DUK_BSWAP32(x32);
	if (x32 != (duk_uint32_t) 0xefbeaddeUL) {
		DUK__FAILED("DUK_BSWAP32");
	}

#if defined(DUK_BSWAP64)
	x64_input = DUK_U64_CONSTANT(0x8899aabbccddeeff);
	x64 = x64_input;
	x64 = DUK_BSWAP64(x64);
	x64_output = x64;
	if (x64_output != (duk_uint64_t) DUK_U64_CONSTANT(0xffeeddccbbaa9988)) {
		DUK__FAILED("DUK_BSWAP64");
	}

	x64 = DUK_U64_CONSTANT(0x8899aabbccddeeff);
	x64 = DUK_BSWAP64(x64);
	if (x64 != (duk_uint64_t) DUK_U64_CONSTANT(0xffeeddccbbaa9988)) {
		DUK__FAILED("DUK_BSWAP64");
	}
#endif

	/* >>> struct.unpack('>d', '4000112233445566'.decode('hex'))
	 * (2.008366013071895,)
	 */

	du.uc[0] = 0x40; du.uc[1] = 0x00; du.uc[2] = 0x11; du.uc[3] = 0x22;
	du.uc[4] = 0x33; du.uc[5] = 0x44; du.uc[6] = 0x55; du.uc[7] = 0x66;
	DUK_DBLUNION_DOUBLE_NTOH(&du);
	du_diff = du.d - 2.008366013071895;
#if 0
	DUK_D(DUK_DPRINT("du_diff: %lg\n", (double) du_diff));
#endif
	if (du_diff > 1e-15) {
		/* Allow very small lenience because some compilers won't parse
		 * exact IEEE double constants (happened in matrix testing with
		 * Linux gcc-4.8 -m32 at least).
		 */
#if 0
		DUK_D(DUK_DPRINT("Result of DUK_DBLUNION_DOUBLE_NTOH: %02x %02x %02x %02x %02x %02x %02x %02x\n",
		            (unsigned int) du.uc[0], (unsigned int) du.uc[1],
		            (unsigned int) du.uc[2], (unsigned int) du.uc[3],
		            (unsigned int) du.uc[4], (unsigned int) du.uc[5],
		            (unsigned int) du.uc[6], (unsigned int) du.uc[7]));
#endif
		DUK__FAILED("DUK_DBLUNION_DOUBLE_NTOH");
	}

	return error_count;
}

/*
 *  Basic double / byte union memory layout.
 */

DUK_LOCAL duk_uint_t duk__selftest_double_union_size(void) {
	duk_uint_t error_count = 0;

	if (sizeof(duk__test_double_union) != 8) {
		DUK__FAILED("invalid union size");
	}

	return error_count;
}

/*
 *  Union aliasing, see misc/clang_aliasing.c.
 */

DUK_LOCAL duk_uint_t duk__selftest_double_aliasing(void) {
	/* This testcase fails when Emscripten-generated code runs on Firefox.
	 * It's not an issue because the failure should only affect packed
	 * duk_tval representation, which is not used with Emscripten.
	 */
#if defined(DUK_USE_PACKED_TVAL)
	duk_uint_t error_count = 0;
	duk__test_double_union a, b;

	/* Test signaling NaN and alias assignment in all endianness combinations.
	 */

	/* little endian */
	a.x[0] = 0x11; a.x[1] = 0x22; a.x[2] = 0x33; a.x[3] = 0x44;
	a.x[4] = 0x00; a.x[5] = 0x00; a.x[6] = 0xf1; a.x[7] = 0xff;
	b = a;
	DUK__DBLUNION_CMP_TRUE(&a, &b);

	/* big endian */
	a.x[0] = 0xff; a.x[1] = 0xf1; a.x[2] = 0x00; a.x[3] = 0x00;
	a.x[4] = 0x44; a.x[5] = 0x33; a.x[6] = 0x22; a.x[7] = 0x11;
	b = a;
	DUK__DBLUNION_CMP_TRUE(&a, &b);

	/* mixed endian */
	a.x[0] = 0x00; a.x[1] = 0x00; a.x[2] = 0xf1; a.x[3] = 0xff;
	a.x[4] = 0x11; a.x[5] = 0x22; a.x[6] = 0x33; a.x[7] = 0x44;
	b = a;
	DUK__DBLUNION_CMP_TRUE(&a, &b);

	return error_count;
#else
	DUK_D(DUK_DPRINT("skip double aliasing self test when duk_tval is not packed"));
	return 0;
#endif
}

/*
 *  Zero sign, see misc/tcc_zerosign2.c.
 */

DUK_LOCAL duk_uint_t duk__selftest_double_zero_sign(void) {
	duk_uint_t error_count = 0;
	duk__test_double_union a, b;

	a.d = 0.0;
	b.d = -a.d;
	DUK__DBLUNION_CMP_FALSE(&a, &b);

	return error_count;
}

/*
 *  Rounding mode: Duktape assumes round-to-nearest, check that this is true.
 *  If we had C99 fenv.h we could check that fegetround() == FE_TONEAREST,
 *  but we don't want to rely on that header; and even if we did, it's good
 *  to ensure the rounding actually works.
 */

DUK_LOCAL duk_uint_t duk__selftest_double_rounding(void) {
	duk_uint_t error_count = 0;
	duk__test_double_union a, b, c;

#if 0
	/* Include <fenv.h> and test manually; these trigger failures: */
	fesetround(FE_UPWARD);
	fesetround(FE_DOWNWARD);
	fesetround(FE_TOWARDZERO);

	/* This is the default and passes. */
	fesetround(FE_TONEAREST);
#endif

	/* Rounding tests check that none of the other modes (round to
	 * +Inf, round to -Inf, round to zero) can be active:
	 * http://www.gnu.org/software/libc/manual/html_node/Rounding.html
	 */

	/* 1.0 + 2^(-53): result is midway between 1.0 and 1.0 + ulp.
	 * Round to nearest: 1.0
	 * Round to +Inf:    1.0 + ulp
	 * Round to -Inf:    1.0
	 * Round to zero:    1.0
	 * => Correct result eliminates round to +Inf.
	 */
	DUK__DOUBLE_INIT(&a, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
	DUK__DOUBLE_INIT(&b, 0x3c, 0xa0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
	duk_memset((void *) &c, 0, sizeof(c));
	c.d = a.d + b.d;
	if (!DUK__DOUBLE_COMPARE(&c, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)) {
		DUK_D(DUK_DPRINT("broken result (native endiannesss): %02x %02x %02x %02x %02x %02x %02x %02x",
		                 (unsigned int) c.x[0], (unsigned int) c.x[1],
		                 (unsigned int) c.x[2], (unsigned int) c.x[3],
		                 (unsigned int) c.x[4], (unsigned int) c.x[5],
		                 (unsigned int) c.x[6], (unsigned int) c.x[7]));
		DUK__FAILED("invalid result from 1.0 + 0.5ulp");
	}

	/* (1.0 + ulp) + 2^(-53): result is midway between 1.0 + ulp and 1.0 + 2*ulp.
	 * Round to nearest: 1.0 + 2*ulp (round to even mantissa)
	 * Round to +Inf:    1.0 + 2*ulp
	 * Round to -Inf:    1.0 + ulp
	 * Round to zero:    1.0 + ulp
	 * => Correct result eliminates round to -Inf and round to zero.
	 */
	DUK__DOUBLE_INIT(&a, 0x3f, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01);
	DUK__DOUBLE_INIT(&b, 0x3c, 0xa0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
	duk_memset((void *) &c, 0, sizeof(c));
	c.d = a.d + b.d;
	if (!DUK__DOUBLE_COMPARE(&c, 0x3f, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02)) {
		DUK_D(DUK_DPRINT("broken result (native endiannesss): %02x %02x %02x %02x %02x %02x %02x %02x",
		                 (unsigned int) c.x[0], (unsigned int) c.x[1],
		                 (unsigned int) c.x[2], (unsigned int) c.x[3],
		                 (unsigned int) c.x[4], (unsigned int) c.x[5],
		                 (unsigned int) c.x[6], (unsigned int) c.x[7]));
		DUK__FAILED("invalid result from (1.0 + ulp) + 0.5ulp");
	}

	/* Could do negative number testing too, but the tests above should
	 * differentiate between IEEE 754 rounding modes.
	 */
	return error_count;
}

/*
 *  fmod(): often a portability issue in embedded or bare platform targets.
 *  Check for at least minimally correct behavior.  Unlike some other math
 *  functions (like cos()) Duktape relies on fmod() internally too.
 */

DUK_LOCAL duk_uint_t duk__selftest_fmod(void) {
	duk_uint_t error_count = 0;
	duk__test_double_union u1, u2;
	volatile duk_double_t t1, t2, t3;

	/* fmod() with integer argument and exponent 2^32 is used by e.g.
	 * ToUint32() and some Duktape internals.
	 */
	u1.d = DUK_FMOD(10.0, 4294967296.0);
	u2.d = 10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	u1.d = DUK_FMOD(4294967306.0, 4294967296.0);
	u2.d = 10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	u1.d = DUK_FMOD(73014444042.0, 4294967296.0);
	u2.d = 10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	/* 52-bit integer split into two parts:
	 * >>> 0x1fedcba9876543
	 * 8987183256397123
	 * >>> float(0x1fedcba9876543) / float(2**53)
	 * 0.9977777777777778
	 */
	u1.d = DUK_FMOD(8987183256397123.0, 4294967296.0);
	u2.d = (duk_double_t) 0xa9876543UL;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);
	t1 = 8987183256397123.0;
	t2 = 4294967296.0;
	t3 = t1 / t2;
	u1.d = DUK_FLOOR(t3);
	u2.d = (duk_double_t) 0x1fedcbUL;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	/* C99 behavior is for fmod() result sign to mathc argument sign. */
	u1.d = DUK_FMOD(-10.0, 4294967296.0);
	u2.d = -10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	u1.d = DUK_FMOD(-4294967306.0, 4294967296.0);
	u2.d = -10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	u1.d = DUK_FMOD(-73014444042.0, 4294967296.0);
	u2.d = -10.0;
	DUK__DBLUNION_CMP_TRUE(&u1, &u2);

	return error_count;
}

/*
 *  Struct size/alignment if platform requires it
 *
 *  There are some compiler specific struct padding pragmas etc in use, this
 *  selftest ensures they're correctly detected and used.
 */

DUK_LOCAL duk_uint_t duk__selftest_struct_align(void) {
	duk_uint_t error_count = 0;

#if (DUK_USE_ALIGN_BY == 4)
	if ((sizeof(duk_hbuffer_fixed) % 4) != 0) {
		DUK__FAILED("sizeof(duk_hbuffer_fixed) not aligned to 4");
	}
#elif (DUK_USE_ALIGN_BY == 8)
	if ((sizeof(duk_hbuffer_fixed) % 8) != 0) {
		DUK__FAILED("sizeof(duk_hbuffer_fixed) not aligned to 8");
	}
#elif (DUK_USE_ALIGN_BY == 1)
	/* no check */
#else
#error invalid DUK_USE_ALIGN_BY
#endif
	return error_count;
}

/*
 *  64-bit arithmetic
 *
 *  There are some platforms/compilers where 64-bit types are available
 *  but don't work correctly.  Test for known cases.
 */

DUK_LOCAL duk_uint_t duk__selftest_64bit_arithmetic(void) {
	duk_uint_t error_count = 0;
#if defined(DUK_USE_64BIT_OPS)
	volatile duk_int64_t i;
	volatile duk_double_t d;

	/* Catch a double-to-int64 cast issue encountered in practice. */
	d = 2147483648.0;
	i = (duk_int64_t) d;
	if (i != DUK_I64_CONSTANT(0x80000000)) {
		DUK__FAILED("casting 2147483648.0 to duk_int64_t failed");
	}
#else
	/* nop */
#endif
	return error_count;
}

/*
 *  Casting
 */

DUK_LOCAL duk_uint_t duk__selftest_cast_double_to_small_uint(void) {
	/*
	 *  https://github.com/svaarala/duktape/issues/127#issuecomment-77863473
	 */

	duk_uint_t error_count = 0;

	duk_double_t d1, d2;
	duk_small_uint_t u;

	duk_double_t d1v, d2v;
	duk_small_uint_t uv;

	/* Test without volatiles */

	d1 = 1.0;
	u = (duk_small_uint_t) d1;
	d2 = (duk_double_t) u;

	if (!(duk_double_equals(d1, 1.0) && u == 1 && duk_double_equals(d2, 1.0) && duk_double_equals(d1, d2))) {
		DUK__FAILED("double to duk_small_uint_t cast failed");
	}

	/* Same test with volatiles */

	d1v = 1.0;
	uv = (duk_small_uint_t) d1v;
	d2v = (duk_double_t) uv;

	if (!(duk_double_equals(d1v, 1.0) && uv == 1 && duk_double_equals(d2v, 1.0) && duk_double_equals(d1v, d2v))) {
		DUK__FAILED("double to duk_small_uint_t cast failed");
	}

	return error_count;
}

DUK_LOCAL duk_uint_t duk__selftest_cast_double_to_uint32(void) {
	/*
	 *  This test fails on an exotic ARM target; double-to-uint
	 *  cast is incorrectly clamped to -signed- int highest value.
	 *
	 *  https://github.com/svaarala/duktape/issues/336
	 */

	duk_uint_t error_count = 0;
	duk_double_t dv;
	duk_uint32_t uv;

	dv = 3735928559.0;  /* 0xdeadbeef in decimal */
	uv = (duk_uint32_t) dv;

	if (uv != 0xdeadbeefUL) {
		DUK__FAILED("double to duk_uint32_t cast failed");
	}

	return error_count;
}

/*
 *  Minimal test of user supplied allocation functions
 *
 *    - Basic alloc + realloc + free cycle
 *
 *    - Realloc to significantly larger size to (hopefully) trigger a
 *      relocation and check that relocation copying works
 */

DUK_LOCAL duk_uint_t duk__selftest_alloc_funcs(duk_alloc_function alloc_func,
                                               duk_realloc_function realloc_func,
                                               duk_free_function free_func,
                                               void *udata) {
	duk_uint_t error_count = 0;
	void *ptr;
	void *new_ptr;
	duk_small_int_t i, j;
	unsigned char x;

	if (alloc_func == NULL || realloc_func == NULL || free_func == NULL) {
		return 0;
	}

	for (i = 1; i <= 256; i++) {
		ptr = alloc_func(udata, (duk_size_t) i);
		if (ptr == NULL) {
			DUK_D(DUK_DPRINT("alloc failed, ignore"));
			continue;  /* alloc failed, ignore */
		}
		for (j = 0; j < i; j++) {
			((unsigned char *) ptr)[j] = (unsigned char) (0x80 + j);
		}
		new_ptr = realloc_func(udata, ptr, 1024);
		if (new_ptr == NULL) {
			DUK_D(DUK_DPRINT("realloc failed, ignore"));
			free_func(udata, ptr);
			continue;  /* realloc failed, ignore */
		}
		ptr = new_ptr;
		for (j = 0; j < i; j++) {
			x = ((unsigned char *) ptr)[j];
			if (x != (unsigned char) (0x80 + j)) {
				DUK_D(DUK_DPRINT("byte at index %ld doesn't match after realloc: %02lx",
				                 (long) j, (unsigned long) x));
				DUK__FAILED("byte compare after realloc");
				break;
			}
		}
		free_func(udata, ptr);
	}

	return error_count;
}

/*
 *  Self test main
 */

DUK_INTERNAL duk_uint_t duk_selftest_run_tests(duk_alloc_function alloc_func,
                                               duk_realloc_function realloc_func,
                                               duk_free_function free_func,
                                               void *udata) {
	duk_uint_t error_count = 0;

	DUK_D(DUK_DPRINT("self test starting"));

	error_count += duk__selftest_types();
	error_count += duk__selftest_packed_tval();
	error_count += duk__selftest_twos_complement();
	error_count += duk__selftest_byte_order();
	error_count += duk__selftest_bswap_macros();
	error_count += duk__selftest_double_union_size();
	error_count += duk__selftest_double_aliasing();
	error_count += duk__selftest_double_zero_sign();
	error_count += duk__selftest_double_rounding();
	error_count += duk__selftest_fmod();
	error_count += duk__selftest_struct_align();
	error_count += duk__selftest_64bit_arithmetic();
	error_count += duk__selftest_cast_double_to_small_uint();
	error_count += duk__selftest_cast_double_to_uint32();
	error_count += duk__selftest_alloc_funcs(alloc_func, realloc_func, free_func, udata);

	DUK_D(DUK_DPRINT("self test complete, total error count: %ld", (long) error_count));

	return error_count;
}

#endif  /* DUK_USE_SELF_TESTS */

/* automatic undefs */
#undef DUK__DBLUNION_CMP_FALSE
#undef DUK__DBLUNION_CMP_TRUE
#undef DUK__DOUBLE_COMPARE
#undef DUK__DOUBLE_INIT
#undef DUK__FAILED
#undef DUK__U32_INIT
/* #include duk_internal.h -> already included */

#if defined(DUK_USE_FASTINT)

/*
 *  Manually optimized double-to-fastint downgrade check.
 *
 *  This check has a large impact on performance, especially for fastint
 *  slow paths, so must be changed carefully.  The code should probably be
 *  optimized for the case where the result does not fit into a fastint,
 *  to minimize the penalty for "slow path code" dealing with fractions etc.
 *
 *  At least on one tested soft float ARM platform double-to-int64 coercion
 *  is very slow (and sometimes produces incorrect results, see self tests).
 *  This algorithm combines a fastint compatibility check and extracting the
 *  integer value from an IEEE double for setting the tagged fastint.  For
 *  other platforms a more naive approach might be better.
 *
 *  See doc/fastint.rst for details.
 */

DUK_INTERNAL DUK_ALWAYS_INLINE void duk_tval_set_number_chkfast_fast(duk_tval *tv, duk_double_t x) {
	duk_double_union du;
	duk_int64_t i;
	duk_small_int_t expt;
	duk_small_int_t shift;

	/* XXX: optimize for packed duk_tval directly? */

	du.d = x;
	i = (duk_int64_t) DUK_DBLUNION_GET_INT64(&du);
	expt = (duk_small_int_t) ((i >> 52) & 0x07ff);
	shift = expt - 1023;

	if (shift >= 0 && shift <= 46) {  /* exponents 1023 to 1069 */
		duk_int64_t t;

		if (((DUK_I64_CONSTANT(0x000fffffffffffff) >> shift) & i) == 0) {
			t = i | DUK_I64_CONSTANT(0x0010000000000000);  /* implicit leading one */
			t = t & DUK_I64_CONSTANT(0x001fffffffffffff);
			t = t >> (52 - shift);
			if (i < 0) {
				t = -t;
			}
			DUK_TVAL_SET_FASTINT(tv, t);
			return;
		}
	} else if (shift == -1023) {  /* exponent 0 */
		if (i >= 0 && (i & DUK_I64_CONSTANT(0x000fffffffffffff)) == 0) {
			/* Note: reject negative zero. */
			DUK_TVAL_SET_FASTINT(tv, (duk_int64_t) 0);
			return;
		}
	} else if (shift == 47) {  /* exponent 1070 */
		if (i < 0 && (i & DUK_I64_CONSTANT(0x000fffffffffffff)) == 0) {
			DUK_TVAL_SET_FASTINT(tv, (duk_int64_t) DUK_FASTINT_MIN);
			return;
		}
	}

	DUK_TVAL_SET_DOUBLE(tv, x);
	return;
}

DUK_INTERNAL DUK_NOINLINE void duk_tval_set_number_chkfast_slow(duk_tval *tv, duk_double_t x) {
	duk_tval_set_number_chkfast_fast(tv, x);
}

/*
 *  Manually optimized number-to-double conversion
 */

#if defined(DUK_USE_FASTINT) && defined(DUK_USE_PACKED_TVAL)
DUK_INTERNAL DUK_ALWAYS_INLINE duk_double_t duk_tval_get_number_packed(duk_tval *tv) {
	duk_double_union du;
	duk_uint64_t t;

	t = (duk_uint64_t) DUK_DBLUNION_GET_UINT64(tv);
	if ((t >> 48) != DUK_TAG_FASTINT) {
		return tv->d;
	} else if (t & DUK_U64_CONSTANT(0x0000800000000000)) {
		t = (duk_uint64_t) (-((duk_int64_t) t));  /* avoid unary minus on unsigned */
		t = t & DUK_U64_CONSTANT(0x0000ffffffffffff);  /* negative */
		t |= DUK_U64_CONSTANT(0xc330000000000000);
		DUK_DBLUNION_SET_UINT64(&du, t);
		return du.d + 4503599627370496.0;  /* 1 << 52 */
	} else if (t != 0) {
		t &= DUK_U64_CONSTANT(0x0000ffffffffffff);  /* positive */
		t |= DUK_U64_CONSTANT(0x4330000000000000);
		DUK_DBLUNION_SET_UINT64(&du, t);
		return du.d - 4503599627370496.0;  /* 1 << 52 */
	} else {
		return 0.0;  /* zero */
	}
}
#endif  /* DUK_USE_FASTINT && DUK_USE_PACKED_TVAL */

#if 0  /* unused */
#if defined(DUK_USE_FASTINT) && !defined(DUK_USE_PACKED_TVAL)
DUK_INTERNAL DUK_ALWAYS_INLINE duk_double_t duk_tval_get_number_unpacked(duk_tval *tv) {
	duk_double_union du;
	duk_uint64_t t;

	DUK_ASSERT(tv->t == DUK_TAG_NUMBER || tv->t == DUK_TAG_FASTINT);

	if (tv->t == DUK_TAG_FASTINT) {
		if (tv->v.fi >= 0) {
			t = DUK_U64_CONSTANT(0x4330000000000000) | (duk_uint64_t) tv->v.fi;
			DUK_DBLUNION_SET_UINT64(&du, t);
			return du.d - 4503599627370496.0;  /* 1 << 52 */
		} else {
			t = DUK_U64_CONSTANT(0xc330000000000000) | (duk_uint64_t) (-tv->v.fi);
			DUK_DBLUNION_SET_UINT64(&du, t);
			return du.d + 4503599627370496.0;  /* 1 << 52 */
		}
	} else {
		return tv->v.d;
	}
}
#endif  /* DUK_USE_FASTINT && DUK_USE_PACKED_TVAL */
#endif  /* 0 */

#if defined(DUK_USE_FASTINT) && !defined(DUK_USE_PACKED_TVAL)
DUK_INTERNAL DUK_ALWAYS_INLINE duk_double_t duk_tval_get_number_unpacked_fastint(duk_tval *tv) {
	duk_double_union du;
	duk_uint64_t t;

	DUK_ASSERT(tv->t == DUK_TAG_FASTINT);

	if (tv->v.fi >= 0) {
		t = DUK_U64_CONSTANT(0x4330000000000000) | (duk_uint64_t) tv->v.fi;
		DUK_DBLUNION_SET_UINT64(&du, t);
		return du.d - 4503599627370496.0;  /* 1 << 52 */
	} else {
		t = DUK_U64_CONSTANT(0xc330000000000000) | (duk_uint64_t) (-tv->v.fi);
		DUK_DBLUNION_SET_UINT64(&du, t);
		return du.d + 4503599627370496.0;  /* 1 << 52 */
	}
}
#endif  /* DUK_USE_FASTINT && DUK_USE_PACKED_TVAL */

#endif  /* DUK_USE_FASTINT */

/*
 *  Assertion helpers.
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL void duk_tval_assert_valid(duk_tval *tv) {
	DUK_ASSERT(tv != NULL);
}
#endif
/*
 *  Unicode support tables automatically generated during build.
 */

/* #include duk_internal.h -> already included */

/*
 *  Unicode tables containing ranges of Unicode characters in a
 *  packed format.  These tables are used to match non-ASCII
 *  characters of complex productions by resorting to a linear
 *  range-by-range comparison.  This is very slow, but is expected
 *  to be very rare in practical ECMAScript source code, and thus
 *  compactness is most important.
 *
 *  The tables are matched using uni_range_match() and the format
 *  is described in tools/extract_chars.py.
 */

#if defined(DUK_USE_SOURCE_NONBMP)
/* IdentifierStart production with ASCII excluded */
/* duk_unicode_ids_noa[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_ids_noa[1116] = {
249,176,176,80,111,7,47,15,47,254,11,197,191,0,72,2,15,115,66,19,50,7,2,34,
2,240,66,244,50,247,185,249,98,241,99,7,241,159,57,240,181,63,31,241,191,
21,18,245,50,15,1,24,27,35,15,2,2,240,239,15,244,156,15,10,241,26,21,6,240,
101,10,4,15,9,240,152,175,39,240,82,127,56,242,100,15,4,8,159,1,240,5,115,
19,240,98,98,4,52,15,2,14,18,47,0,27,9,85,19,240,98,98,18,18,31,17,50,15,5,
47,2,130,34,240,98,98,18,68,15,4,15,1,31,9,12,115,19,240,98,98,18,68,15,16,
18,47,1,15,3,2,84,34,52,18,2,20,20,36,191,8,15,38,114,34,240,114,240,4,15,
12,38,31,16,5,114,34,240,114,146,68,15,18,2,31,1,31,4,114,34,241,147,15,2,
6,41,47,10,86,240,36,240,130,130,3,111,44,242,2,29,111,44,18,2,66,240,130,
2,146,26,3,66,15,7,63,18,15,49,114,241,79,13,79,101,241,191,6,15,2,85,52,4,
24,37,205,15,3,241,98,6,3,241,178,255,224,63,35,54,32,35,63,25,35,63,17,35,
54,32,35,62,47,41,35,63,51,241,127,0,240,47,70,53,79,254,21,227,240,18,240,
166,243,180,168,194,63,0,240,47,0,240,47,0,194,47,1,242,79,21,5,15,53,244,
152,67,241,34,6,243,107,240,255,35,240,227,76,241,197,240,175,40,240,122,
242,95,68,15,79,241,255,3,111,41,240,238,27,241,207,12,241,79,27,43,241,67,
136,241,179,47,27,50,82,20,6,251,15,50,255,224,8,53,63,22,53,55,32,32,32,
47,15,63,37,38,32,66,38,67,53,92,98,38,246,96,224,240,44,245,112,80,57,32,
68,112,32,32,35,42,51,100,80,240,63,25,255,233,107,241,242,241,242,247,87,
52,29,241,98,6,3,242,136,15,2,240,122,98,98,98,98,98,98,98,111,66,15,254,
12,146,240,184,132,52,95,70,114,47,74,35,111,27,47,78,240,63,11,242,127,0,
255,224,244,255,240,0,138,143,60,255,240,4,14,47,2,255,227,127,243,95,30,
63,253,79,0,177,240,111,31,240,47,15,63,64,241,152,63,87,63,37,52,242,42,
34,35,47,7,240,255,36,240,15,34,243,5,64,33,207,12,191,7,240,191,13,143,31,
240,224,240,36,41,180,47,25,240,146,39,240,111,7,64,79,34,32,65,52,48,32,
240,162,58,130,213,53,53,166,38,47,27,43,159,99,240,255,255,0,26,150,223,7,
95,33,255,240,0,255,143,254,6,3,245,175,24,109,70,2,146,194,66,2,18,18,245,
207,19,255,224,93,240,79,48,63,38,241,171,246,100,47,119,241,111,10,127,10,
207,73,69,53,53,50,241,91,47,10,47,3,33,46,61,241,79,107,243,127,37,255,
223,13,79,33,242,31,16,239,14,111,22,191,14,63,20,87,36,241,207,142,240,79,
20,95,20,95,24,159,36,248,239,254,2,154,240,107,127,138,83,2,241,194,20,3,
240,123,240,122,240,255,51,240,50,27,240,107,240,175,56,242,135,31,50,15,1,
50,34,240,223,28,240,212,240,223,21,114,240,207,13,242,107,240,107,240,62,
240,47,96,243,159,41,242,62,242,62,241,79,254,13,15,13,176,159,6,248,207,7,
223,37,243,223,29,241,47,9,240,207,20,240,240,207,19,64,223,32,240,3,240,
112,32,241,95,2,47,9,244,102,32,35,46,41,143,31,241,135,49,63,6,38,33,36,
64,240,64,212,249,15,37,240,67,240,96,241,47,32,240,97,32,250,175,31,241,
179,241,111,32,240,96,242,223,27,224,243,159,11,253,127,28,246,111,48,241,
16,249,39,63,23,240,32,32,240,224,191,24,128,240,112,207,30,240,80,241,79,
41,255,152,47,21,240,48,242,63,14,246,38,33,47,22,240,112,240,181,33,47,16,
240,0,255,224,59,240,63,254,0,31,254,40,207,88,245,255,3,251,79,254,155,15,
254,50,31,254,236,95,254,19,159,255,0,16,173,255,225,43,143,15,246,63,14,
240,79,32,240,35,241,31,5,111,3,255,225,164,243,15,114,243,182,15,52,207,
50,18,15,14,255,240,0,110,169,255,225,229,255,240,1,64,31,254,1,31,35,47,3,
57,255,224,126,255,231,248,245,182,196,136,159,255,0,6,90,244,82,243,114,
19,3,19,50,178,2,98,243,18,51,114,98,240,194,50,66,4,98,255,224,70,63,9,47,
9,47,15,47,9,47,15,47,9,47,15,47,9,47,15,47,9,39,255,232,40,241,219,111,2,
15,254,6,95,28,255,228,8,251,95,45,243,72,15,254,58,131,47,11,33,32,48,41,
35,32,32,112,80,32,32,34,33,32,48,32,32,32,32,33,32,51,38,35,35,32,41,47,1,
98,36,47,1,255,240,0,3,143,255,0,149,201,241,191,254,242,124,252,227,255,
240,0,87,79,0,255,240,0,194,63,254,177,63,254,17,0,
};
#else
/* IdentifierStart production with ASCII and non-BMP excluded */
/* duk_unicode_ids_noabmp[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_ids_noabmp[625] = {
249,176,176,80,111,7,47,15,47,254,11,197,191,0,72,2,15,115,66,19,50,7,2,34,
2,240,66,244,50,247,185,249,98,241,99,7,241,159,57,240,181,63,31,241,191,
21,18,245,50,15,1,24,27,35,15,2,2,240,239,15,244,156,15,10,241,26,21,6,240,
101,10,4,15,9,240,152,175,39,240,82,127,56,242,100,15,4,8,159,1,240,5,115,
19,240,98,98,4,52,15,2,14,18,47,0,27,9,85,19,240,98,98,18,18,31,17,50,15,5,
47,2,130,34,240,98,98,18,68,15,4,15,1,31,9,12,115,19,240,98,98,18,68,15,16,
18,47,1,15,3,2,84,34,52,18,2,20,20,36,191,8,15,38,114,34,240,114,240,4,15,
12,38,31,16,5,114,34,240,114,146,68,15,18,2,31,1,31,4,114,34,241,147,15,2,
6,41,47,10,86,240,36,240,130,130,3,111,44,242,2,29,111,44,18,2,66,240,130,
2,146,26,3,66,15,7,63,18,15,49,114,241,79,13,79,101,241,191,6,15,2,85,52,4,
24,37,205,15,3,241,98,6,3,241,178,255,224,63,35,54,32,35,63,25,35,63,17,35,
54,32,35,62,47,41,35,63,51,241,127,0,240,47,70,53,79,254,21,227,240,18,240,
166,243,180,168,194,63,0,240,47,0,240,47,0,194,47,1,242,79,21,5,15,53,244,
152,67,241,34,6,243,107,240,255,35,240,227,76,241,197,240,175,40,240,122,
242,95,68,15,79,241,255,3,111,41,240,238,27,241,207,12,241,79,27,43,241,67,
136,241,179,47,27,50,82,20,6,251,15,50,255,224,8,53,63,22,53,55,32,32,32,
47,15,63,37,38,32,66,38,67,53,92,98,38,246,96,224,240,44,245,112,80,57,32,
68,112,32,32,35,42,51,100,80,240,63,25,255,233,107,241,242,241,242,247,87,
52,29,241,98,6,3,242,136,15,2,240,122,98,98,98,98,98,98,98,111,66,15,254,
12,146,240,184,132,52,95,70,114,47,74,35,111,27,47,78,240,63,11,242,127,0,
255,224,244,255,240,0,138,143,60,255,240,4,14,47,2,255,227,127,243,95,30,
63,253,79,0,177,240,111,31,240,47,15,63,64,241,152,63,87,63,37,52,242,42,
34,35,47,7,240,255,36,240,15,34,243,5,64,33,207,12,191,7,240,191,13,143,31,
240,224,240,36,41,180,47,25,240,146,39,240,111,7,64,79,34,32,65,52,48,32,
240,162,58,130,213,53,53,166,38,47,27,43,159,99,240,255,255,0,26,150,223,7,
95,33,255,240,0,255,143,254,6,3,245,175,24,109,70,2,146,194,66,2,18,18,245,
207,19,255,224,93,240,79,48,63,38,241,171,246,100,47,119,241,111,10,127,10,
207,73,69,53,53,50,0,
};
#endif

#if defined(DUK_USE_SOURCE_NONBMP)
/* IdentifierStart production with Letter and ASCII excluded */
/* duk_unicode_ids_m_let_noa[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_ids_m_let_noa[42] = {
255,240,0,94,18,255,233,99,241,51,63,254,215,32,240,184,240,2,255,240,6,89,
249,255,240,4,148,79,37,255,224,192,9,15,120,79,255,0,15,30,245,240,
};
#else
/* IdentifierStart production with Letter, ASCII, and non-BMP excluded */
/* duk_unicode_ids_m_let_noabmp[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_ids_m_let_noabmp[24] = {
255,240,0,94,18,255,233,99,241,51,63,254,215,32,240,184,240,2,255,240,6,89,
249,0,
};
#endif

#if defined(DUK_USE_SOURCE_NONBMP)
/* IdentifierPart production with IdentifierStart and ASCII excluded */
/* duk_unicode_idp_m_ids_noa[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_idp_m_ids_noa[576] = {
255,225,243,246,15,254,0,116,255,191,29,32,33,33,32,243,170,242,47,15,112,
245,118,53,49,35,57,240,144,241,15,11,244,218,240,25,241,56,160,240,163,40,
34,36,241,210,246,158,47,17,242,130,47,2,38,177,57,240,50,242,160,38,49,50,
160,177,57,240,0,50,242,160,36,81,50,64,240,107,64,194,242,160,39,34,34,
240,97,57,181,34,242,160,38,49,50,145,177,57,240,64,242,212,66,35,160,240,
9,240,36,242,182,34,35,129,193,57,240,50,242,160,38,34,35,129,193,57,240,
35,242,145,38,34,35,160,177,57,240,65,243,128,85,32,39,121,49,242,240,54,
215,41,244,144,56,197,57,243,1,121,192,32,32,81,242,63,4,33,106,47,20,160,
245,111,4,41,211,82,34,54,67,235,46,255,225,179,47,254,42,98,240,242,240,
241,241,1,243,47,16,160,57,241,50,57,245,209,241,64,246,139,91,185,247,41,
242,244,242,185,47,13,58,121,240,141,243,68,242,31,1,201,240,56,210,241,12,
57,241,237,242,47,4,153,121,246,130,47,5,80,112,50,251,143,42,36,255,225,0,
31,35,31,5,15,109,197,4,191,254,175,34,247,240,245,47,16,255,225,30,95,91,
31,255,0,100,121,159,55,5,159,18,31,66,31,254,0,64,64,80,240,148,244,161,
242,79,2,185,127,2,234,240,231,240,188,241,227,242,29,240,25,192,185,242,
29,208,145,57,241,50,242,64,34,49,97,32,241,180,97,253,231,33,57,255,240,3,
225,128,255,225,213,240,15,2,240,4,31,10,47,178,159,23,15,254,27,16,253,64,
248,116,255,224,25,159,254,68,178,33,99,241,162,80,249,113,255,225,49,57,
159,254,16,10,250,18,242,126,241,25,240,19,241,250,242,121,114,241,109,41,
97,241,224,210,242,45,147,73,244,75,112,249,43,105,115,242,145,38,49,50,
160,177,54,68,251,47,2,169,80,244,63,4,217,252,118,56,240,209,244,79,1,240,
25,244,60,153,244,94,89,254,78,249,121,253,150,54,64,240,233,241,166,35,
144,170,242,15,0,255,224,137,114,127,2,159,42,240,98,223,108,84,2,18,98,9,
159,34,66,18,73,159,254,3,211,255,240,3,165,217,247,132,242,214,240,185,
255,226,233,2,242,120,63,255,0,59,254,31,255,0,3,186,68,89,115,111,16,63,
134,47,254,71,223,34,255,224,244,242,117,242,41,15,0,15,8,66,239,254,68,70,
47,1,54,33,36,255,118,169,255,224,150,223,254,76,166,245,246,105,255,240,
192,105,175,224,0,
};
#else
/* IdentifierPart production with IdentifierStart, ASCII, and non-BMP excluded */
/* duk_unicode_idp_m_ids_noabmp[] */
/*
 *  Automatically generated by extract_chars.py, do not edit!
 */

const duk_uint8_t duk_unicode_idp_m_ids_noabmp[358] = {
255,225,243,246,15,254,0,116,255,191,29,32,33,33,32,243,170,242,47,15,112,
245,118,53,49,35,57,240,144,241,15,11,244,218,240,25,241,56,160,240,163,40,
34,36,241,210,246,158,47,17,242,130,47,2,38,177,57,240,50,242,160,38,49,50,
160,177,57,240,0,50,242,160,36,81,50,64,240,107,64,194,242,160,39,34,34,
240,97,57,181,34,242,160,38,49,50,145,177,57,240,64,242,212,66,35,160,240,
9,240,36,242,182,34,35,129,193,57,240,50,242,160,38,34,35,129,193,57,240,
35,242,145,38,34,35,160,177,57,240,65,243,128,85,32,39,121,49,242,240,54,
215,41,244,144,56,197,57,243,1,121,192,32,32,81,242,63,4,33,106,47,20,160,
245,111,4,41,211,82,34,54,67,235,46,255,225,179,47,254,42,98,240,242,240,
241,241,1,243,47,16,160,57,241,50,57,245,209,241,64,246,139,91,185,247,41,
242,244,242,185,47,13,58,121,240,141,243,68,242,31,1,201,240,56,210,241,12,
57,241,237,242,47,4,153,121,246,130,47,5,80,112,50,251,143,42,36,255,225,0,
31,35,31,5,15,109,197,4,191,254,175,34,247,240,245,47,16,255,225,30,95,91,
31,255,0,100,121,159,55,5,159,18,31,66,31,254,0,64,64,80,240,148,244,161,
242,79,2,185,127,2,234,240,231,240,188,241,227,242,29,240,25,192,185,242,
29,208,145,57,241,50,242,64,34,49,97,32,241,180,97,253,231,33,57,255,240,3,
225,128,255,225,213,240,15,2,240,4,31,10,47,178,159,23,0,
};
#endif

/*
 *  Case conversion tables generated using tools/extract_caseconv.py.
 */

/* duk_unicode_caseconv_uc[] */
/* duk_unicode_caseconv_lc[] */

/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

const duk_uint8_t duk_unicode_caseconv_uc[1411] = {
152,3,128,3,0,184,7,192,6,192,112,35,242,199,224,64,74,192,49,32,128,162,
128,108,65,1,189,129,254,131,3,173,3,136,6,7,98,7,34,68,15,12,14,140,72,30,
104,28,112,32,67,0,65,4,0,138,0,128,4,1,88,65,76,83,8,104,14,72,43,16,253,
28,189,6,39,240,39,224,24,114,12,16,132,16,248,0,248,64,129,241,1,241,128,
195,228,3,229,2,7,204,7,206,4,15,160,15,164,6,31,96,31,104,16,62,224,63,
116,8,125,200,127,32,32,251,176,254,208,33,247,129,255,128,67,239,67,253,
64,135,223,7,254,129,15,216,15,220,2,31,208,31,216,4,63,192,63,208,8,133,
192,133,128,129,38,129,37,177,162,195,2,192,5,229,160,2,20,9,170,220,4,232,
40,127,160,255,144,154,136,4,4,4,0,192,9,152,9,144,48,19,160,19,145,0,41,
96,41,69,192,94,128,94,65,128,193,128,193,2,1,161,1,160,6,3,104,3,102,8,7,
56,7,52,64,14,248,14,240,144,31,144,31,130,128,68,96,68,66,64,145,192,145,
130,129,184,129,184,2,3,217,3,216,24,8,194,8,192,68,18,44,18,40,216,38,16,
38,8,112,77,16,77,6,3,192,35,192,18,199,168,71,168,24,15,168,143,172,132,
44,104,44,103,6,89,2,89,0,200,179,176,179,172,21,50,13,50,1,122,104,26,104,
1,212,228,116,228,65,233,204,233,204,143,211,189,83,188,130,167,127,167,
126,11,79,35,79,32,10,158,94,158,88,85,61,173,61,160,97,192,107,64,107,1,0,
226,128,226,3,1,198,1,196,6,3,228,3,226,8,10,0,6,152,16,31,192,31,184,34,
199,50,199,32,65,128,196,0,195,130,1,185,1,184,4,4,205,79,84,8,0,192,143,0,
142,193,1,52,128,203,2,45,39,16,199,5,253,0,11,80,57,192,15,240,23,128,19,
16,4,144,23,240,5,48,24,0,36,48,25,32,25,16,25,80,31,96,25,144,25,128,25,
160,35,208,25,224,34,0,26,128,26,112,27,240,31,112,29,208,24,224,31,48,31,
16,37,2,198,240,37,18,198,208,37,34,199,0,37,48,24,16,37,64,24,96,37,144,
24,240,37,176,25,0,37,202,122,176,38,0,25,48,38,26,122,192,38,48,25,64,38,
90,120,208,38,128,25,112,38,178,198,32,38,202,122,208,39,18,198,224,39,32,
25,208,39,80,25,240,39,210,198,64,40,42,124,80,40,122,123,16,40,128,26,224,
40,144,36,64,40,192,36,80,41,32,27,112,41,218,123,32,41,234,123,0,52,80,57,
144,55,112,55,96,58,192,56,96,60,32,58,48,60,192,56,192,61,0,57,32,61,16,
57,128,61,80,58,96,61,96,58,0,61,112,60,240,63,0,57,160,63,16,58,16,63,32,
63,144,63,48,55,240,63,80,57,80,76,240,76,1,200,0,65,33,200,16,65,65,200,
32,65,225,200,80,66,33,200,96,66,161,200,112,70,33,200,138,100,161,215,154,
119,209,215,210,198,49,216,234,124,97,233,177,230,1,251,224,57,145,254,81,
254,194,20,226,19,34,24,66,24,50,198,18,198,2,198,80,35,162,198,96,35,226,
207,50,207,42,120,202,120,186,121,74,124,74,124,58,124,42,181,58,123,60,
192,27,240,2,152,2,152,10,76,5,120,0,156,3,225,0,37,1,134,1,200,96,115,32,
97,0,96,32,118,24,29,40,24,64,24,8,44,60,10,106,10,164,61,45,0,36,1,152,
143,75,192,10,128,97,3,211,16,2,184,24,80,244,204,0,178,6,20,61,53,0,32,
129,95,15,168,64,116,160,98,99,234,88,29,40,24,152,24,0,250,166,7,74,6,38,
6,2,62,173,129,210,129,137,129,161,15,192,67,225,0,115,35,240,48,248,72,28,
200,252,20,62,20,7,50,63,7,15,133,129,204,143,194,67,225,128,115,35,240,
176,248,104,28,200,252,52,62,28,7,50,63,15,15,135,129,204,143,196,67,225,0,
115,35,241,48,248,72,28,200,252,84,62,20,7,50,63,23,15,133,129,204,143,198,
67,225,128,115,35,241,176,248,104,28,200,252,116,62,28,7,50,63,31,15,135,
129,204,143,200,67,229,0,115,35,242,48,249,72,28,200,252,148,62,84,7,50,63,
39,15,149,129,204,143,202,67,229,128,115,35,242,176,249,104,28,200,252,180,
62,92,7,50,63,47,15,151,129,204,143,204,67,229,0,115,35,243,48,249,72,28,
200,252,212,62,84,7,50,63,55,15,149,129,204,143,206,67,229,128,115,35,243,
176,249,104,28,200,252,244,62,92,7,50,63,63,15,151,129,204,143,208,67,237,
0,115,35,244,48,251,72,28,200,253,20,62,212,7,50,63,71,15,181,129,204,143,
210,67,237,128,115,35,244,176,251,104,28,200,253,52,62,220,7,50,63,79,15,
183,129,204,143,212,67,237,0,115,35,245,48,251,72,28,200,253,84,62,212,7,
50,63,87,15,181,129,204,143,214,67,237,128,115,35,245,176,251,104,28,200,
253,116,62,220,7,50,63,95,15,183,129,204,143,217,67,247,64,115,35,246,112,
28,136,28,200,253,164,7,12,7,50,63,109,1,200,129,161,15,219,224,114,32,104,
64,115,35,247,144,28,136,28,200,254,20,63,148,7,50,63,135,1,203,129,204,
143,226,64,113,32,115,35,248,208,28,184,26,16,254,62,7,46,6,132,7,50,63,
153,1,203,129,204,143,233,96,115,32,97,0,96,3,250,120,28,200,24,64,24,8,
254,180,7,50,6,132,63,175,129,204,129,132,1,161,15,241,96,116,160,97,0,96,
3,252,120,29,40,24,64,24,8,255,36,7,66,6,38,63,205,1,210,129,161,15,243,
224,116,160,97,0,104,67,254,80,255,208,28,200,255,156,7,82,7,50,63,233,1,
199,129,204,143,251,64,117,32,104,67,254,248,29,72,26,16,28,200,255,228,7,
82,7,51,246,1,0,35,0,35,125,128,192,8,192,9,63,96,80,2,48,2,103,216,30,0,
140,0,140,0,147,246,9,128,35,0,35,0,38,125,130,192,10,96,10,159,96,208,2,
152,2,167,216,156,10,136,10,141,246,41,2,162,2,154,253,138,192,168,128,167,
127,98,208,42,112,42,55,216,188,10,136,10,122,
};
const duk_uint8_t duk_unicode_caseconv_lc[706] = {
160,3,0,3,128,184,6,192,7,192,112,24,144,37,96,64,54,32,81,64,128,226,0,
235,65,129,199,1,230,130,3,145,3,177,34,7,70,7,134,36,15,244,13,236,24,32,
0,34,129,0,65,0,67,4,0,166,32,172,41,132,40,11,64,19,9,208,85,184,80,19,
240,19,248,12,57,32,33,160,172,114,244,67,244,24,248,64,248,0,129,241,129,
241,0,195,229,3,228,2,7,206,7,204,4,15,164,15,160,6,31,104,31,96,16,63,16,
63,0,32,126,96,126,64,64,253,64,253,0,129,251,129,251,0,67,247,67,238,0,
135,242,7,220,130,15,236,15,232,2,31,218,31,118,4,63,208,63,192,8,127,168,
125,232,16,255,192,251,192,33,255,161,247,192,68,44,4,46,4,9,45,137,52,13,
22,0,22,24,47,44,126,2,63,5,254,67,254,130,106,48,16,0,16,19,0,38,64,38,96,
192,78,64,78,132,0,165,0,165,151,1,121,1,122,6,3,4,3,6,8,6,128,6,132,24,13,
152,13,160,32,28,176,28,193,32,59,192,59,226,64,124,128,124,193,0,252,0,
252,148,2,34,2,35,18,4,140,4,142,20,13,192,13,196,16,30,192,30,200,192,70,
0,70,18,32,145,64,145,102,193,48,65,48,131,130,104,2,104,176,30,0,30,1,150,
61,64,61,66,192,125,100,125,68,33,99,57,99,64,50,200,2,200,22,69,157,101,
157,128,169,144,41,144,75,211,64,83,64,142,167,34,167,35,15,78,101,78,102,
126,157,230,157,232,21,59,245,59,248,90,121,10,121,16,84,242,212,242,226,
169,237,41,237,67,12,3,76,5,0,8,6,176,6,180,16,14,32,14,48,48,28,80,28,96,
64,126,224,127,0,139,28,139,28,193,6,3,14,3,16,8,6,224,6,228,21,61,80,19,
48,32,3,1,150,2,105,4,4,118,4,120,8,67,28,180,156,23,240,192,94,0,63,192,
96,64,148,192,97,128,149,0,99,128,119,64,99,192,150,64,100,0,150,192,100,
64,100,128,100,192,152,0,101,0,152,192,101,192,154,0,102,0,102,64,103,64,
156,128,103,192,157,64,105,192,106,0,107,128,162,0,109,192,164,128,124,64,
124,192,125,128,101,64,125,192,111,192,136,0,103,128,142,139,25,64,143,64,
102,128,143,139,25,128,144,192,96,0,145,0,162,64,145,64,163,0,221,128,221,
192,223,192,252,192,225,128,235,0,227,0,243,0,243,192,245,192,253,0,238,0,
254,64,252,129,48,1,51,199,167,128,55,199,239,7,236,199,243,7,240,199,251,
7,249,71,255,7,252,200,73,128,242,72,74,128,26,200,74,192,57,72,76,136,83,
136,96,200,97,11,24,11,24,75,24,128,154,203,24,199,95,75,25,0,159,75,27,64,
148,75,27,128,156,75,27,192,148,11,28,0,148,139,60,139,60,233,223,71,94,
105,226,233,227,41,227,64,153,105,234,192,151,41,235,0,152,105,235,64,155,
41,236,0,167,169,236,64,161,233,236,128,167,105,236,234,212,233,240,169,
240,233,241,41,229,41,241,64,160,169,241,135,99,128,128,152,64,13,32,96,
224,
};

#if defined(DUK_USE_REGEXP_CANON_WORKAROUND)
/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

const duk_uint16_t duk_unicode_re_canon_lookup[65536] = {
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,
28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,
53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,
78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,65,66,67,68,69,70,
71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,123,124,125,
126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,
162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,
180,924,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,
198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,
216,217,218,219,220,221,222,223,192,193,194,195,196,197,198,199,200,201,
202,203,204,205,206,207,208,209,210,211,212,213,214,247,216,217,218,219,
220,221,222,376,256,256,258,258,260,260,262,262,264,264,266,266,268,268,
270,270,272,272,274,274,276,276,278,278,280,280,282,282,284,284,286,286,
288,288,290,290,292,292,294,294,296,296,298,298,300,300,302,302,304,305,
306,306,308,308,310,310,312,313,313,315,315,317,317,319,319,321,321,323,
323,325,325,327,327,329,330,330,332,332,334,334,336,336,338,338,340,340,
342,342,344,344,346,346,348,348,350,350,352,352,354,354,356,356,358,358,
360,360,362,362,364,364,366,366,368,368,370,370,372,372,374,374,376,377,
377,379,379,381,381,383,579,385,386,386,388,388,390,391,391,393,394,395,
395,397,398,399,400,401,401,403,404,502,406,407,408,408,573,411,412,413,
544,415,416,416,418,418,420,420,422,423,423,425,426,427,428,428,430,431,
431,433,434,435,435,437,437,439,440,440,442,443,444,444,446,503,448,449,
450,451,452,452,452,455,455,455,458,458,458,461,461,463,463,465,465,467,
467,469,469,471,471,473,473,475,475,398,478,478,480,480,482,482,484,484,
486,486,488,488,490,490,492,492,494,494,496,497,497,497,500,500,502,503,
504,504,506,506,508,508,510,510,512,512,514,514,516,516,518,518,520,520,
522,522,524,524,526,526,528,528,530,530,532,532,534,534,536,536,538,538,
540,540,542,542,544,545,546,546,548,548,550,550,552,552,554,554,556,556,
558,558,560,560,562,562,564,565,566,567,568,569,570,571,571,573,574,11390,
11391,577,577,579,580,581,582,582,584,584,586,586,588,588,590,590,11375,
11373,11376,385,390,597,393,394,600,399,602,400,42923L,605,606,607,403,
42924L,610,404,612,42893L,42922L,615,407,406,42926L,11362,42925L,621,622,
412,624,11374,413,627,628,415,630,631,632,633,634,635,636,11364,638,639,
422,641,42949L,425,644,645,646,42929L,430,580,433,434,581,653,654,655,656,
657,439,659,660,661,662,663,664,665,666,667,668,42930L,42928L,671,672,673,
674,675,676,677,678,679,680,681,682,683,684,685,686,687,688,689,690,691,
692,693,694,695,696,697,698,699,700,701,702,703,704,705,706,707,708,709,
710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725,726,727,
728,729,730,731,732,733,734,735,736,737,738,739,740,741,742,743,744,745,
746,747,748,749,750,751,752,753,754,755,756,757,758,759,760,761,762,763,
764,765,766,767,768,769,770,771,772,773,774,775,776,777,778,779,780,781,
782,783,784,785,786,787,788,789,790,791,792,793,794,795,796,797,798,799,
800,801,802,803,804,805,806,807,808,809,810,811,812,813,814,815,816,817,
818,819,820,821,822,823,824,825,826,827,828,829,830,831,832,833,834,835,
836,921,838,839,840,841,842,843,844,845,846,847,848,849,850,851,852,853,
854,855,856,857,858,859,860,861,862,863,864,865,866,867,868,869,870,871,
872,873,874,875,876,877,878,879,880,880,882,882,884,885,886,886,888,889,
890,1021,1022,1023,894,895,896,897,898,899,900,901,902,903,904,905,906,907,
908,909,910,911,912,913,914,915,916,917,918,919,920,921,922,923,924,925,
926,927,928,929,930,931,932,933,934,935,936,937,938,939,902,904,905,906,
944,913,914,915,916,917,918,919,920,921,922,923,924,925,926,927,928,929,
931,931,932,933,934,935,936,937,938,939,908,910,911,975,914,920,978,979,
980,934,928,975,984,984,986,986,988,988,990,990,992,992,994,994,996,996,
998,998,1000,1000,1002,1002,1004,1004,1006,1006,922,929,1017,895,1012,917,
1014,1015,1015,1017,1018,1018,1020,1021,1022,1023,1024,1025,1026,1027,1028,
1029,1030,1031,1032,1033,1034,1035,1036,1037,1038,1039,1040,1041,1042,1043,
1044,1045,1046,1047,1048,1049,1050,1051,1052,1053,1054,1055,1056,1057,1058,
1059,1060,1061,1062,1063,1064,1065,1066,1067,1068,1069,1070,1071,1040,1041,
1042,1043,1044,1045,1046,1047,1048,1049,1050,1051,1052,1053,1054,1055,1056,
1057,1058,1059,1060,1061,1062,1063,1064,1065,1066,1067,1068,1069,1070,1071,
1024,1025,1026,1027,1028,1029,1030,1031,1032,1033,1034,1035,1036,1037,1038,
1039,1120,1120,1122,1122,1124,1124,1126,1126,1128,1128,1130,1130,1132,1132,
1134,1134,1136,1136,1138,1138,1140,1140,1142,1142,1144,1144,1146,1146,1148,
1148,1150,1150,1152,1152,1154,1155,1156,1157,1158,1159,1160,1161,1162,1162,
1164,1164,1166,1166,1168,1168,1170,1170,1172,1172,1174,1174,1176,1176,1178,
1178,1180,1180,1182,1182,1184,1184,1186,1186,1188,1188,1190,1190,1192,1192,
1194,1194,1196,1196,1198,1198,1200,1200,1202,1202,1204,1204,1206,1206,1208,
1208,1210,1210,1212,1212,1214,1214,1216,1217,1217,1219,1219,1221,1221,1223,
1223,1225,1225,1227,1227,1229,1229,1216,1232,1232,1234,1234,1236,1236,1238,
1238,1240,1240,1242,1242,1244,1244,1246,1246,1248,1248,1250,1250,1252,1252,
1254,1254,1256,1256,1258,1258,1260,1260,1262,1262,1264,1264,1266,1266,1268,
1268,1270,1270,1272,1272,1274,1274,1276,1276,1278,1278,1280,1280,1282,1282,
1284,1284,1286,1286,1288,1288,1290,1290,1292,1292,1294,1294,1296,1296,1298,
1298,1300,1300,1302,1302,1304,1304,1306,1306,1308,1308,1310,1310,1312,1312,
1314,1314,1316,1316,1318,1318,1320,1320,1322,1322,1324,1324,1326,1326,1328,
1329,1330,1331,1332,1333,1334,1335,1336,1337,1338,1339,1340,1341,1342,1343,
1344,1345,1346,1347,1348,1349,1350,1351,1352,1353,1354,1355,1356,1357,1358,
1359,1360,1361,1362,1363,1364,1365,1366,1367,1368,1369,1370,1371,1372,1373,
1374,1375,1376,1329,1330,1331,1332,1333,1334,1335,1336,1337,1338,1339,1340,
1341,1342,1343,1344,1345,1346,1347,1348,1349,1350,1351,1352,1353,1354,1355,
1356,1357,1358,1359,1360,1361,1362,1363,1364,1365,1366,1415,1416,1417,1418,
1419,1420,1421,1422,1423,1424,1425,1426,1427,1428,1429,1430,1431,1432,1433,
1434,1435,1436,1437,1438,1439,1440,1441,1442,1443,1444,1445,1446,1447,1448,
1449,1450,1451,1452,1453,1454,1455,1456,1457,1458,1459,1460,1461,1462,1463,
1464,1465,1466,1467,1468,1469,1470,1471,1472,1473,1474,1475,1476,1477,1478,
1479,1480,1481,1482,1483,1484,1485,1486,1487,1488,1489,1490,1491,1492,1493,
1494,1495,1496,1497,1498,1499,1500,1501,1502,1503,1504,1505,1506,1507,1508,
1509,1510,1511,1512,1513,1514,1515,1516,1517,1518,1519,1520,1521,1522,1523,
1524,1525,1526,1527,1528,1529,1530,1531,1532,1533,1534,1535,1536,1537,1538,
1539,1540,1541,1542,1543,1544,1545,1546,1547,1548,1549,1550,1551,1552,1553,
1554,1555,1556,1557,1558,1559,1560,1561,1562,1563,1564,1565,1566,1567,1568,
1569,1570,1571,1572,1573,1574,1575,1576,1577,1578,1579,1580,1581,1582,1583,
1584,1585,1586,1587,1588,1589,1590,1591,1592,1593,1594,1595,1596,1597,1598,
1599,1600,1601,1602,1603,1604,1605,1606,1607,1608,1609,1610,1611,1612,1613,
1614,1615,1616,1617,1618,1619,1620,1621,1622,1623,1624,1625,1626,1627,1628,
1629,1630,1631,1632,1633,1634,1635,1636,1637,1638,1639,1640,1641,1642,1643,
1644,1645,1646,1647,1648,1649,1650,1651,1652,1653,1654,1655,1656,1657,1658,
1659,1660,1661,1662,1663,1664,1665,1666,1667,1668,1669,1670,1671,1672,1673,
1674,1675,1676,1677,1678,1679,1680,1681,1682,1683,1684,1685,1686,1687,1688,
1689,1690,1691,1692,1693,1694,1695,1696,1697,1698,1699,1700,1701,1702,1703,
1704,1705,1706,1707,1708,1709,1710,1711,1712,1713,1714,1715,1716,1717,1718,
1719,1720,1721,1722,1723,1724,1725,1726,1727,1728,1729,1730,1731,1732,1733,
1734,1735,1736,1737,1738,1739,1740,1741,1742,1743,1744,1745,1746,1747,1748,
1749,1750,1751,1752,1753,1754,1755,1756,1757,1758,1759,1760,1761,1762,1763,
1764,1765,1766,1767,1768,1769,1770,1771,1772,1773,1774,1775,1776,1777,1778,
1779,1780,1781,1782,1783,1784,1785,1786,1787,1788,1789,1790,1791,1792,1793,
1794,1795,1796,1797,1798,1799,1800,1801,1802,1803,1804,1805,1806,1807,1808,
1809,1810,1811,1812,1813,1814,1815,1816,1817,1818,1819,1820,1821,1822,1823,
1824,1825,1826,1827,1828,1829,1830,1831,1832,1833,1834,1835,1836,1837,1838,
1839,1840,1841,1842,1843,1844,1845,1846,1847,1848,1849,1850,1851,1852,1853,
1854,1855,1856,1857,1858,1859,1860,1861,1862,1863,1864,1865,1866,1867,1868,
1869,1870,1871,1872,1873,1874,1875,1876,1877,1878,1879,1880,1881,1882,1883,
1884,1885,1886,1887,1888,1889,1890,1891,1892,1893,1894,1895,1896,1897,1898,
1899,1900,1901,1902,1903,1904,1905,1906,1907,1908,1909,1910,1911,1912,1913,
1914,1915,1916,1917,1918,1919,1920,1921,1922,1923,1924,1925,1926,1927,1928,
1929,1930,1931,1932,1933,1934,1935,1936,1937,1938,1939,1940,1941,1942,1943,
1944,1945,1946,1947,1948,1949,1950,1951,1952,1953,1954,1955,1956,1957,1958,
1959,1960,1961,1962,1963,1964,1965,1966,1967,1968,1969,1970,1971,1972,1973,
1974,1975,1976,1977,1978,1979,1980,1981,1982,1983,1984,1985,1986,1987,1988,
1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,
2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,
2019,2020,2021,2022,2023,2024,2025,2026,2027,2028,2029,2030,2031,2032,2033,
2034,2035,2036,2037,2038,2039,2040,2041,2042,2043,2044,2045,2046,2047,2048,
2049,2050,2051,2052,2053,2054,2055,2056,2057,2058,2059,2060,2061,2062,2063,
2064,2065,2066,2067,2068,2069,2070,2071,2072,2073,2074,2075,2076,2077,2078,
2079,2080,2081,2082,2083,2084,2085,2086,2087,2088,2089,2090,2091,2092,2093,
2094,2095,2096,2097,2098,2099,2100,2101,2102,2103,2104,2105,2106,2107,2108,
2109,2110,2111,2112,2113,2114,2115,2116,2117,2118,2119,2120,2121,2122,2123,
2124,2125,2126,2127,2128,2129,2130,2131,2132,2133,2134,2135,2136,2137,2138,
2139,2140,2141,2142,2143,2144,2145,2146,2147,2148,2149,2150,2151,2152,2153,
2154,2155,2156,2157,2158,2159,2160,2161,2162,2163,2164,2165,2166,2167,2168,
2169,2170,2171,2172,2173,2174,2175,2176,2177,2178,2179,2180,2181,2182,2183,
2184,2185,2186,2187,2188,2189,2190,2191,2192,2193,2194,2195,2196,2197,2198,
2199,2200,2201,2202,2203,2204,2205,2206,2207,2208,2209,2210,2211,2212,2213,
2214,2215,2216,2217,2218,2219,2220,2221,2222,2223,2224,2225,2226,2227,2228,
2229,2230,2231,2232,2233,2234,2235,2236,2237,2238,2239,2240,2241,2242,2243,
2244,2245,2246,2247,2248,2249,2250,2251,2252,2253,2254,2255,2256,2257,2258,
2259,2260,2261,2262,2263,2264,2265,2266,2267,2268,2269,2270,2271,2272,2273,
2274,2275,2276,2277,2278,2279,2280,2281,2282,2283,2284,2285,2286,2287,2288,
2289,2290,2291,2292,2293,2294,2295,2296,2297,2298,2299,2300,2301,2302,2303,
2304,2305,2306,2307,2308,2309,2310,2311,2312,2313,2314,2315,2316,2317,2318,
2319,2320,2321,2322,2323,2324,2325,2326,2327,2328,2329,2330,2331,2332,2333,
2334,2335,2336,2337,2338,2339,2340,2341,2342,2343,2344,2345,2346,2347,2348,
2349,2350,2351,2352,2353,2354,2355,2356,2357,2358,2359,2360,2361,2362,2363,
2364,2365,2366,2367,2368,2369,2370,2371,2372,2373,2374,2375,2376,2377,2378,
2379,2380,2381,2382,2383,2384,2385,2386,2387,2388,2389,2390,2391,2392,2393,
2394,2395,2396,2397,2398,2399,2400,2401,2402,2403,2404,2405,2406,2407,2408,
2409,2410,2411,2412,2413,2414,2415,2416,2417,2418,2419,2420,2421,2422,2423,
2424,2425,2426,2427,2428,2429,2430,2431,2432,2433,2434,2435,2436,2437,2438,
2439,2440,2441,2442,2443,2444,2445,2446,2447,2448,2449,2450,2451,2452,2453,
2454,2455,2456,2457,2458,2459,2460,2461,2462,2463,2464,2465,2466,2467,2468,
2469,2470,2471,2472,2473,2474,2475,2476,2477,2478,2479,2480,2481,2482,2483,
2484,2485,2486,2487,2488,2489,2490,2491,2492,2493,2494,2495,2496,2497,2498,
2499,2500,2501,2502,2503,2504,2505,2506,2507,2508,2509,2510,2511,2512,2513,
2514,2515,2516,2517,2518,2519,2520,2521,2522,2523,2524,2525,2526,2527,2528,
2529,2530,2531,2532,2533,2534,2535,2536,2537,2538,2539,2540,2541,2542,2543,
2544,2545,2546,2547,2548,2549,2550,2551,2552,2553,2554,2555,2556,2557,2558,
2559,2560,2561,2562,2563,2564,2565,2566,2567,2568,2569,2570,2571,2572,2573,
2574,2575,2576,2577,2578,2579,2580,2581,2582,2583,2584,2585,2586,2587,2588,
2589,2590,2591,2592,2593,2594,2595,2596,2597,2598,2599,2600,2601,2602,2603,
2604,2605,2606,2607,2608,2609,2610,2611,2612,2613,2614,2615,2616,2617,2618,
2619,2620,2621,2622,2623,2624,2625,2626,2627,2628,2629,2630,2631,2632,2633,
2634,2635,2636,2637,2638,2639,2640,2641,2642,2643,2644,2645,2646,2647,2648,
2649,2650,2651,2652,2653,2654,2655,2656,2657,2658,2659,2660,2661,2662,2663,
2664,2665,2666,2667,2668,2669,2670,2671,2672,2673,2674,2675,2676,2677,2678,
2679,2680,2681,2682,2683,2684,2685,2686,2687,2688,2689,2690,2691,2692,2693,
2694,2695,2696,2697,2698,2699,2700,2701,2702,2703,2704,2705,2706,2707,2708,
2709,2710,2711,2712,2713,2714,2715,2716,2717,2718,2719,2720,2721,2722,2723,
2724,2725,2726,2727,2728,2729,2730,2731,2732,2733,2734,2735,2736,2737,2738,
2739,2740,2741,2742,2743,2744,2745,2746,2747,2748,2749,2750,2751,2752,2753,
2754,2755,2756,2757,2758,2759,2760,2761,2762,2763,2764,2765,2766,2767,2768,
2769,2770,2771,2772,2773,2774,2775,2776,2777,2778,2779,2780,2781,2782,2783,
2784,2785,2786,2787,2788,2789,2790,2791,2792,2793,2794,2795,2796,2797,2798,
2799,2800,2801,2802,2803,2804,2805,2806,2807,2808,2809,2810,2811,2812,2813,
2814,2815,2816,2817,2818,2819,2820,2821,2822,2823,2824,2825,2826,2827,2828,
2829,2830,2831,2832,2833,2834,2835,2836,2837,2838,2839,2840,2841,2842,2843,
2844,2845,2846,2847,2848,2849,2850,2851,2852,2853,2854,2855,2856,2857,2858,
2859,2860,2861,2862,2863,2864,2865,2866,2867,2868,2869,2870,2871,2872,2873,
2874,2875,2876,2877,2878,2879,2880,2881,2882,2883,2884,2885,2886,2887,2888,
2889,2890,2891,2892,2893,2894,2895,2896,2897,2898,2899,2900,2901,2902,2903,
2904,2905,2906,2907,2908,2909,2910,2911,2912,2913,2914,2915,2916,2917,2918,
2919,2920,2921,2922,2923,2924,2925,2926,2927,2928,2929,2930,2931,2932,2933,
2934,2935,2936,2937,2938,2939,2940,2941,2942,2943,2944,2945,2946,2947,2948,
2949,2950,2951,2952,2953,2954,2955,2956,2957,2958,2959,2960,2961,2962,2963,
2964,2965,2966,2967,2968,2969,2970,2971,2972,2973,2974,2975,2976,2977,2978,
2979,2980,2981,2982,2983,2984,2985,2986,2987,2988,2989,2990,2991,2992,2993,
2994,2995,2996,2997,2998,2999,3000,3001,3002,3003,3004,3005,3006,3007,3008,
3009,3010,3011,3012,3013,3014,3015,3016,3017,3018,3019,3020,3021,3022,3023,
3024,3025,3026,3027,3028,3029,3030,3031,3032,3033,3034,3035,3036,3037,3038,
3039,3040,3041,3042,3043,3044,3045,3046,3047,3048,3049,3050,3051,3052,3053,
3054,3055,3056,3057,3058,3059,3060,3061,3062,3063,3064,3065,3066,3067,3068,
3069,3070,3071,3072,3073,3074,3075,3076,3077,3078,3079,3080,3081,3082,3083,
3084,3085,3086,3087,3088,3089,3090,3091,3092,3093,3094,3095,3096,3097,3098,
3099,3100,3101,3102,3103,3104,3105,3106,3107,3108,3109,3110,3111,3112,3113,
3114,3115,3116,3117,3118,3119,3120,3121,3122,3123,3124,3125,3126,3127,3128,
3129,3130,3131,3132,3133,3134,3135,3136,3137,3138,3139,3140,3141,3142,3143,
3144,3145,3146,3147,3148,3149,3150,3151,3152,3153,3154,3155,3156,3157,3158,
3159,3160,3161,3162,3163,3164,3165,3166,3167,3168,3169,3170,3171,3172,3173,
3174,3175,3176,3177,3178,3179,3180,3181,3182,3183,3184,3185,3186,3187,3188,
3189,3190,3191,3192,3193,3194,3195,3196,3197,3198,3199,3200,3201,3202,3203,
3204,3205,3206,3207,3208,3209,3210,3211,3212,3213,3214,3215,3216,3217,3218,
3219,3220,3221,3222,3223,3224,3225,3226,3227,3228,3229,3230,3231,3232,3233,
3234,3235,3236,3237,3238,3239,3240,3241,3242,3243,3244,3245,3246,3247,3248,
3249,3250,3251,3252,3253,3254,3255,3256,3257,3258,3259,3260,3261,3262,3263,
3264,3265,3266,3267,3268,3269,3270,3271,3272,3273,3274,3275,3276,3277,3278,
3279,3280,3281,3282,3283,3284,3285,3286,3287,3288,3289,3290,3291,3292,3293,
3294,3295,3296,3297,3298,3299,3300,3301,3302,3303,3304,3305,3306,3307,3308,
3309,3310,3311,3312,3313,3314,3315,3316,3317,3318,3319,3320,3321,3322,3323,
3324,3325,3326,3327,3328,3329,3330,3331,3332,3333,3334,3335,3336,3337,3338,
3339,3340,3341,3342,3343,3344,3345,3346,3347,3348,3349,3350,3351,3352,3353,
3354,3355,3356,3357,3358,3359,3360,3361,3362,3363,3364,3365,3366,3367,3368,
3369,3370,3371,3372,3373,3374,3375,3376,3377,3378,3379,3380,3381,3382,3383,
3384,3385,3386,3387,3388,3389,3390,3391,3392,3393,3394,3395,3396,3397,3398,
3399,3400,3401,3402,3403,3404,3405,3406,3407,3408,3409,3410,3411,3412,3413,
3414,3415,3416,3417,3418,3419,3420,3421,3422,3423,3424,3425,3426,3427,3428,
3429,3430,3431,3432,3433,3434,3435,3436,3437,3438,3439,3440,3441,3442,3443,
3444,3445,3446,3447,3448,3449,3450,3451,3452,3453,3454,3455,3456,3457,3458,
3459,3460,3461,3462,3463,3464,3465,3466,3467,3468,3469,3470,3471,3472,3473,
3474,3475,3476,3477,3478,3479,3480,3481,3482,3483,3484,3485,3486,3487,3488,
3489,3490,3491,3492,3493,3494,3495,3496,3497,3498,3499,3500,3501,3502,3503,
3504,3505,3506,3507,3508,3509,3510,3511,3512,3513,3514,3515,3516,3517,3518,
3519,3520,3521,3522,3523,3524,3525,3526,3527,3528,3529,3530,3531,3532,3533,
3534,3535,3536,3537,3538,3539,3540,3541,3542,3543,3544,3545,3546,3547,3548,
3549,3550,3551,3552,3553,3554,3555,3556,3557,3558,3559,3560,3561,3562,3563,
3564,3565,3566,3567,3568,3569,3570,3571,3572,3573,3574,3575,3576,3577,3578,
3579,3580,3581,3582,3583,3584,3585,3586,3587,3588,3589,3590,3591,3592,3593,
3594,3595,3596,3597,3598,3599,3600,3601,3602,3603,3604,3605,3606,3607,3608,
3609,3610,3611,3612,3613,3614,3615,3616,3617,3618,3619,3620,3621,3622,3623,
3624,3625,3626,3627,3628,3629,3630,3631,3632,3633,3634,3635,3636,3637,3638,
3639,3640,3641,3642,3643,3644,3645,3646,3647,3648,3649,3650,3651,3652,3653,
3654,3655,3656,3657,3658,3659,3660,3661,3662,3663,3664,3665,3666,3667,3668,
3669,3670,3671,3672,3673,3674,3675,3676,3677,3678,3679,3680,3681,3682,3683,
3684,3685,3686,3687,3688,3689,3690,3691,3692,3693,3694,3695,3696,3697,3698,
3699,3700,3701,3702,3703,3704,3705,3706,3707,3708,3709,3710,3711,3712,3713,
3714,3715,3716,3717,3718,3719,3720,3721,3722,3723,3724,3725,3726,3727,3728,
3729,3730,3731,3732,3733,3734,3735,3736,3737,3738,3739,3740,3741,3742,3743,
3744,3745,3746,3747,3748,3749,3750,3751,3752,3753,3754,3755,3756,3757,3758,
3759,3760,3761,3762,3763,3764,3765,3766,3767,3768,3769,3770,3771,3772,3773,
3774,3775,3776,3777,3778,3779,3780,3781,3782,3783,3784,3785,3786,3787,3788,
3789,3790,3791,3792,3793,3794,3795,3796,3797,3798,3799,3800,3801,3802,3803,
3804,3805,3806,3807,3808,3809,3810,3811,3812,3813,3814,3815,3816,3817,3818,
3819,3820,3821,3822,3823,3824,3825,3826,3827,3828,3829,3830,3831,3832,3833,
3834,3835,3836,3837,3838,3839,3840,3841,3842,3843,3844,3845,3846,3847,3848,
3849,3850,3851,3852,3853,3854,3855,3856,3857,3858,3859,3860,3861,3862,3863,
3864,3865,3866,3867,3868,3869,3870,3871,3872,3873,3874,3875,3876,3877,3878,
3879,3880,3881,3882,3883,3884,3885,3886,3887,3888,3889,3890,3891,3892,3893,
3894,3895,3896,3897,3898,3899,3900,3901,3902,3903,3904,3905,3906,3907,3908,
3909,3910,3911,3912,3913,3914,3915,3916,3917,3918,3919,3920,3921,3922,3923,
3924,3925,3926,3927,3928,3929,3930,3931,3932,3933,3934,3935,3936,3937,3938,
3939,3940,3941,3942,3943,3944,3945,3946,3947,3948,3949,3950,3951,3952,3953,
3954,3955,3956,3957,3958,3959,3960,3961,3962,3963,3964,3965,3966,3967,3968,
3969,3970,3971,3972,3973,3974,3975,3976,3977,3978,3979,3980,3981,3982,3983,
3984,3985,3986,3987,3988,3989,3990,3991,3992,3993,3994,3995,3996,3997,3998,
3999,4000,4001,4002,4003,4004,4005,4006,4007,4008,4009,4010,4011,4012,4013,
4014,4015,4016,4017,4018,4019,4020,4021,4022,4023,4024,4025,4026,4027,4028,
4029,4030,4031,4032,4033,4034,4035,4036,4037,4038,4039,4040,4041,4042,4043,
4044,4045,4046,4047,4048,4049,4050,4051,4052,4053,4054,4055,4056,4057,4058,
4059,4060,4061,4062,4063,4064,4065,4066,4067,4068,4069,4070,4071,4072,4073,
4074,4075,4076,4077,4078,4079,4080,4081,4082,4083,4084,4085,4086,4087,4088,
4089,4090,4091,4092,4093,4094,4095,4096,4097,4098,4099,4100,4101,4102,4103,
4104,4105,4106,4107,4108,4109,4110,4111,4112,4113,4114,4115,4116,4117,4118,
4119,4120,4121,4122,4123,4124,4125,4126,4127,4128,4129,4130,4131,4132,4133,
4134,4135,4136,4137,4138,4139,4140,4141,4142,4143,4144,4145,4146,4147,4148,
4149,4150,4151,4152,4153,4154,4155,4156,4157,4158,4159,4160,4161,4162,4163,
4164,4165,4166,4167,4168,4169,4170,4171,4172,4173,4174,4175,4176,4177,4178,
4179,4180,4181,4182,4183,4184,4185,4186,4187,4188,4189,4190,4191,4192,4193,
4194,4195,4196,4197,4198,4199,4200,4201,4202,4203,4204,4205,4206,4207,4208,
4209,4210,4211,4212,4213,4214,4215,4216,4217,4218,4219,4220,4221,4222,4223,
4224,4225,4226,4227,4228,4229,4230,4231,4232,4233,4234,4235,4236,4237,4238,
4239,4240,4241,4242,4243,4244,4245,4246,4247,4248,4249,4250,4251,4252,4253,
4254,4255,4256,4257,4258,4259,4260,4261,4262,4263,4264,4265,4266,4267,4268,
4269,4270,4271,4272,4273,4274,4275,4276,4277,4278,4279,4280,4281,4282,4283,
4284,4285,4286,4287,4288,4289,4290,4291,4292,4293,4294,4295,4296,4297,4298,
4299,4300,4301,4302,4303,7312,7313,7314,7315,7316,7317,7318,7319,7320,7321,
7322,7323,7324,7325,7326,7327,7328,7329,7330,7331,7332,7333,7334,7335,7336,
7337,7338,7339,7340,7341,7342,7343,7344,7345,7346,7347,7348,7349,7350,7351,
7352,7353,7354,4347,4348,7357,7358,7359,4352,4353,4354,4355,4356,4357,4358,
4359,4360,4361,4362,4363,4364,4365,4366,4367,4368,4369,4370,4371,4372,4373,
4374,4375,4376,4377,4378,4379,4380,4381,4382,4383,4384,4385,4386,4387,4388,
4389,4390,4391,4392,4393,4394,4395,4396,4397,4398,4399,4400,4401,4402,4403,
4404,4405,4406,4407,4408,4409,4410,4411,4412,4413,4414,4415,4416,4417,4418,
4419,4420,4421,4422,4423,4424,4425,4426,4427,4428,4429,4430,4431,4432,4433,
4434,4435,4436,4437,4438,4439,4440,4441,4442,4443,4444,4445,4446,4447,4448,
4449,4450,4451,4452,4453,4454,4455,4456,4457,4458,4459,4460,4461,4462,4463,
4464,4465,4466,4467,4468,4469,4470,4471,4472,4473,4474,4475,4476,4477,4478,
4479,4480,4481,4482,4483,4484,4485,4486,4487,4488,4489,4490,4491,4492,4493,
4494,4495,4496,4497,4498,4499,4500,4501,4502,4503,4504,4505,4506,4507,4508,
4509,4510,4511,4512,4513,4514,4515,4516,4517,4518,4519,4520,4521,4522,4523,
4524,4525,4526,4527,4528,4529,4530,4531,4532,4533,4534,4535,4536,4537,4538,
4539,4540,4541,4542,4543,4544,4545,4546,4547,4548,4549,4550,4551,4552,4553,
4554,4555,4556,4557,4558,4559,4560,4561,4562,4563,4564,4565,4566,4567,4568,
4569,4570,4571,4572,4573,4574,4575,4576,4577,4578,4579,4580,4581,4582,4583,
4584,4585,4586,4587,4588,4589,4590,4591,4592,4593,4594,4595,4596,4597,4598,
4599,4600,4601,4602,4603,4604,4605,4606,4607,4608,4609,4610,4611,4612,4613,
4614,4615,4616,4617,4618,4619,4620,4621,4622,4623,4624,4625,4626,4627,4628,
4629,4630,4631,4632,4633,4634,4635,4636,4637,4638,4639,4640,4641,4642,4643,
4644,4645,4646,4647,4648,4649,4650,4651,4652,4653,4654,4655,4656,4657,4658,
4659,4660,4661,4662,4663,4664,4665,4666,4667,4668,4669,4670,4671,4672,4673,
4674,4675,4676,4677,4678,4679,4680,4681,4682,4683,4684,4685,4686,4687,4688,
4689,4690,4691,4692,4693,4694,4695,4696,4697,4698,4699,4700,4701,4702,4703,
4704,4705,4706,4707,4708,4709,4710,4711,4712,4713,4714,4715,4716,4717,4718,
4719,4720,4721,4722,4723,4724,4725,4726,4727,4728,4729,4730,4731,4732,4733,
4734,4735,4736,4737,4738,4739,4740,4741,4742,4743,4744,4745,4746,4747,4748,
4749,4750,4751,4752,4753,4754,4755,4756,4757,4758,4759,4760,4761,4762,4763,
4764,4765,4766,4767,4768,4769,4770,4771,4772,4773,4774,4775,4776,4777,4778,
4779,4780,4781,4782,4783,4784,4785,4786,4787,4788,4789,4790,4791,4792,4793,
4794,4795,4796,4797,4798,4799,4800,4801,4802,4803,4804,4805,4806,4807,4808,
4809,4810,4811,4812,4813,4814,4815,4816,4817,4818,4819,4820,4821,4822,4823,
4824,4825,4826,4827,4828,4829,4830,4831,4832,4833,4834,4835,4836,4837,4838,
4839,4840,4841,4842,4843,4844,4845,4846,4847,4848,4849,4850,4851,4852,4853,
4854,4855,4856,4857,4858,4859,4860,4861,4862,4863,4864,4865,4866,4867,4868,
4869,4870,4871,4872,4873,4874,4875,4876,4877,4878,4879,4880,4881,4882,4883,
4884,4885,4886,4887,4888,4889,4890,4891,4892,4893,4894,4895,4896,4897,4898,
4899,4900,4901,4902,4903,4904,4905,4906,4907,4908,4909,4910,4911,4912,4913,
4914,4915,4916,4917,4918,4919,4920,4921,4922,4923,4924,4925,4926,4927,4928,
4929,4930,4931,4932,4933,4934,4935,4936,4937,4938,4939,4940,4941,4942,4943,
4944,4945,4946,4947,4948,4949,4950,4951,4952,4953,4954,4955,4956,4957,4958,
4959,4960,4961,4962,4963,4964,4965,4966,4967,4968,4969,4970,4971,4972,4973,
4974,4975,4976,4977,4978,4979,4980,4981,4982,4983,4984,4985,4986,4987,4988,
4989,4990,4991,4992,4993,4994,4995,4996,4997,4998,4999,5000,5001,5002,5003,
5004,5005,5006,5007,5008,5009,5010,5011,5012,5013,5014,5015,5016,5017,5018,
5019,5020,5021,5022,5023,5024,5025,5026,5027,5028,5029,5030,5031,5032,5033,
5034,5035,5036,5037,5038,5039,5040,5041,5042,5043,5044,5045,5046,5047,5048,
5049,5050,5051,5052,5053,5054,5055,5056,5057,5058,5059,5060,5061,5062,5063,
5064,5065,5066,5067,5068,5069,5070,5071,5072,5073,5074,5075,5076,5077,5078,
5079,5080,5081,5082,5083,5084,5085,5086,5087,5088,5089,5090,5091,5092,5093,
5094,5095,5096,5097,5098,5099,5100,5101,5102,5103,5104,5105,5106,5107,5108,
5109,5110,5111,5104,5105,5106,5107,5108,5109,5118,5119,5120,5121,5122,5123,
5124,5125,5126,5127,5128,5129,5130,5131,5132,5133,5134,5135,5136,5137,5138,
5139,5140,5141,5142,5143,5144,5145,5146,5147,5148,5149,5150,5151,5152,5153,
5154,5155,5156,5157,5158,5159,5160,5161,5162,5163,5164,5165,5166,5167,5168,
5169,5170,5171,5172,5173,5174,5175,5176,5177,5178,5179,5180,5181,5182,5183,
5184,5185,5186,5187,5188,5189,5190,5191,5192,5193,5194,5195,5196,5197,5198,
5199,5200,5201,5202,5203,5204,5205,5206,5207,5208,5209,5210,5211,5212,5213,
5214,5215,5216,5217,5218,5219,5220,5221,5222,5223,5224,5225,5226,5227,5228,
5229,5230,5231,5232,5233,5234,5235,5236,5237,5238,5239,5240,5241,5242,5243,
5244,5245,5246,5247,5248,5249,5250,5251,5252,5253,5254,5255,5256,5257,5258,
5259,5260,5261,5262,5263,5264,5265,5266,5267,5268,5269,5270,5271,5272,5273,
5274,5275,5276,5277,5278,5279,5280,5281,5282,5283,5284,5285,5286,5287,5288,
5289,5290,5291,5292,5293,5294,5295,5296,5297,5298,5299,5300,5301,5302,5303,
5304,5305,5306,5307,5308,5309,5310,5311,5312,5313,5314,5315,5316,5317,5318,
5319,5320,5321,5322,5323,5324,5325,5326,5327,5328,5329,5330,5331,5332,5333,
5334,5335,5336,5337,5338,5339,5340,5341,5342,5343,5344,5345,5346,5347,5348,
5349,5350,5351,5352,5353,5354,5355,5356,5357,5358,5359,5360,5361,5362,5363,
5364,5365,5366,5367,5368,5369,5370,5371,5372,5373,5374,5375,5376,5377,5378,
5379,5380,5381,5382,5383,5384,5385,5386,5387,5388,5389,5390,5391,5392,5393,
5394,5395,5396,5397,5398,5399,5400,5401,5402,5403,5404,5405,5406,5407,5408,
5409,5410,5411,5412,5413,5414,5415,5416,5417,5418,5419,5420,5421,5422,5423,
5424,5425,5426,5427,5428,5429,5430,5431,5432,5433,5434,5435,5436,5437,5438,
5439,5440,5441,5442,5443,5444,5445,5446,5447,5448,5449,5450,5451,5452,5453,
5454,5455,5456,5457,5458,5459,5460,5461,5462,5463,5464,5465,5466,5467,5468,
5469,5470,5471,5472,5473,5474,5475,5476,5477,5478,5479,5480,5481,5482,5483,
5484,5485,5486,5487,5488,5489,5490,5491,5492,5493,5494,5495,5496,5497,5498,
5499,5500,5501,5502,5503,5504,5505,5506,5507,5508,5509,5510,5511,5512,5513,
5514,5515,5516,5517,5518,5519,5520,5521,5522,5523,5524,5525,5526,5527,5528,
5529,5530,5531,5532,5533,5534,5535,5536,5537,5538,5539,5540,5541,5542,5543,
5544,5545,5546,5547,5548,5549,5550,5551,5552,5553,5554,5555,5556,5557,5558,
5559,5560,5561,5562,5563,5564,5565,5566,5567,5568,5569,5570,5571,5572,5573,
5574,5575,5576,5577,5578,5579,5580,5581,5582,5583,5584,5585,5586,5587,5588,
5589,5590,5591,5592,5593,5594,5595,5596,5597,5598,5599,5600,5601,5602,5603,
5604,5605,5606,5607,5608,5609,5610,5611,5612,5613,5614,5615,5616,5617,5618,
5619,5620,5621,5622,5623,5624,5625,5626,5627,5628,5629,5630,5631,5632,5633,
5634,5635,5636,5637,5638,5639,5640,5641,5642,5643,5644,5645,5646,5647,5648,
5649,5650,5651,5652,5653,5654,5655,5656,5657,5658,5659,5660,5661,5662,5663,
5664,5665,5666,5667,5668,5669,5670,5671,5672,5673,5674,5675,5676,5677,5678,
5679,5680,5681,5682,5683,5684,5685,5686,5687,5688,5689,5690,5691,5692,5693,
5694,5695,5696,5697,5698,5699,5700,5701,5702,5703,5704,5705,5706,5707,5708,
5709,5710,5711,5712,5713,5714,5715,5716,5717,5718,5719,5720,5721,5722,5723,
5724,5725,5726,5727,5728,5729,5730,5731,5732,5733,5734,5735,5736,5737,5738,
5739,5740,5741,5742,5743,5744,5745,5746,5747,5748,5749,5750,5751,5752,5753,
5754,5755,5756,5757,5758,5759,5760,5761,5762,5763,5764,5765,5766,5767,5768,
5769,5770,5771,5772,5773,5774,5775,5776,5777,5778,5779,5780,5781,5782,5783,
5784,5785,5786,5787,5788,5789,5790,5791,5792,5793,5794,5795,5796,5797,5798,
5799,5800,5801,5802,5803,5804,5805,5806,5807,5808,5809,5810,5811,5812,5813,
5814,5815,5816,5817,5818,5819,5820,5821,5822,5823,5824,5825,5826,5827,5828,
5829,5830,5831,5832,5833,5834,5835,5836,5837,5838,5839,5840,5841,5842,5843,
5844,5845,5846,5847,5848,5849,5850,5851,5852,5853,5854,5855,5856,5857,5858,
5859,5860,5861,5862,5863,5864,5865,5866,5867,5868,5869,5870,5871,5872,5873,
5874,5875,5876,5877,5878,5879,5880,5881,5882,5883,5884,5885,5886,5887,5888,
5889,5890,5891,5892,5893,5894,5895,5896,5897,5898,5899,5900,5901,5902,5903,
5904,5905,5906,5907,5908,5909,5910,5911,5912,5913,5914,5915,5916,5917,5918,
5919,5920,5921,5922,5923,5924,5925,5926,5927,5928,5929,5930,5931,5932,5933,
5934,5935,5936,5937,5938,5939,5940,5941,5942,5943,5944,5945,5946,5947,5948,
5949,5950,5951,5952,5953,5954,5955,5956,5957,5958,5959,5960,5961,5962,5963,
5964,5965,5966,5967,5968,5969,5970,5971,5972,5973,5974,5975,5976,5977,5978,
5979,5980,5981,5982,5983,5984,5985,5986,5987,5988,5989,5990,5991,5992,5993,
5994,5995,5996,5997,5998,5999,6000,6001,6002,6003,6004,6005,6006,6007,6008,
6009,6010,6011,6012,6013,6014,6015,6016,6017,6018,6019,6020,6021,6022,6023,
6024,6025,6026,6027,6028,6029,6030,6031,6032,6033,6034,6035,6036,6037,6038,
6039,6040,6041,6042,6043,6044,6045,6046,6047,6048,6049,6050,6051,6052,6053,
6054,6055,6056,6057,6058,6059,6060,6061,6062,6063,6064,6065,6066,6067,6068,
6069,6070,6071,6072,6073,6074,6075,6076,6077,6078,6079,6080,6081,6082,6083,
6084,6085,6086,6087,6088,6089,6090,6091,6092,6093,6094,6095,6096,6097,6098,
6099,6100,6101,6102,6103,6104,6105,6106,6107,6108,6109,6110,6111,6112,6113,
6114,6115,6116,6117,6118,6119,6120,6121,6122,6123,6124,6125,6126,6127,6128,
6129,6130,6131,6132,6133,6134,6135,6136,6137,6138,6139,6140,6141,6142,6143,
6144,6145,6146,6147,6148,6149,6150,6151,6152,6153,6154,6155,6156,6157,6158,
6159,6160,6161,6162,6163,6164,6165,6166,6167,6168,6169,6170,6171,6172,6173,
6174,6175,6176,6177,6178,6179,6180,6181,6182,6183,6184,6185,6186,6187,6188,
6189,6190,6191,6192,6193,6194,6195,6196,6197,6198,6199,6200,6201,6202,6203,
6204,6205,6206,6207,6208,6209,6210,6211,6212,6213,6214,6215,6216,6217,6218,
6219,6220,6221,6222,6223,6224,6225,6226,6227,6228,6229,6230,6231,6232,6233,
6234,6235,6236,6237,6238,6239,6240,6241,6242,6243,6244,6245,6246,6247,6248,
6249,6250,6251,6252,6253,6254,6255,6256,6257,6258,6259,6260,6261,6262,6263,
6264,6265,6266,6267,6268,6269,6270,6271,6272,6273,6274,6275,6276,6277,6278,
6279,6280,6281,6282,6283,6284,6285,6286,6287,6288,6289,6290,6291,6292,6293,
6294,6295,6296,6297,6298,6299,6300,6301,6302,6303,6304,6305,6306,6307,6308,
6309,6310,6311,6312,6313,6314,6315,6316,6317,6318,6319,6320,6321,6322,6323,
6324,6325,6326,6327,6328,6329,6330,6331,6332,6333,6334,6335,6336,6337,6338,
6339,6340,6341,6342,6343,6344,6345,6346,6347,6348,6349,6350,6351,6352,6353,
6354,6355,6356,6357,6358,6359,6360,6361,6362,6363,6364,6365,6366,6367,6368,
6369,6370,6371,6372,6373,6374,6375,6376,6377,6378,6379,6380,6381,6382,6383,
6384,6385,6386,6387,6388,6389,6390,6391,6392,6393,6394,6395,6396,6397,6398,
6399,6400,6401,6402,6403,6404,6405,6406,6407,6408,6409,6410,6411,6412,6413,
6414,6415,6416,6417,6418,6419,6420,6421,6422,6423,6424,6425,6426,6427,6428,
6429,6430,6431,6432,6433,6434,6435,6436,6437,6438,6439,6440,6441,6442,6443,
6444,6445,6446,6447,6448,6449,6450,6451,6452,6453,6454,6455,6456,6457,6458,
6459,6460,6461,6462,6463,6464,6465,6466,6467,6468,6469,6470,6471,6472,6473,
6474,6475,6476,6477,6478,6479,6480,6481,6482,6483,6484,6485,6486,6487,6488,
6489,6490,6491,6492,6493,6494,6495,6496,6497,6498,6499,6500,6501,6502,6503,
6504,6505,6506,6507,6508,6509,6510,6511,6512,6513,6514,6515,6516,6517,6518,
6519,6520,6521,6522,6523,6524,6525,6526,6527,6528,6529,6530,6531,6532,6533,
6534,6535,6536,6537,6538,6539,6540,6541,6542,6543,6544,6545,6546,6547,6548,
6549,6550,6551,6552,6553,6554,6555,6556,6557,6558,6559,6560,6561,6562,6563,
6564,6565,6566,6567,6568,6569,6570,6571,6572,6573,6574,6575,6576,6577,6578,
6579,6580,6581,6582,6583,6584,6585,6586,6587,6588,6589,6590,6591,6592,6593,
6594,6595,6596,6597,6598,6599,6600,6601,6602,6603,6604,6605,6606,6607,6608,
6609,6610,6611,6612,6613,6614,6615,6616,6617,6618,6619,6620,6621,6622,6623,
6624,6625,6626,6627,6628,6629,6630,6631,6632,6633,6634,6635,6636,6637,6638,
6639,6640,6641,6642,6643,6644,6645,6646,6647,6648,6649,6650,6651,6652,6653,
6654,6655,6656,6657,6658,6659,6660,6661,6662,6663,6664,6665,6666,6667,6668,
6669,6670,6671,6672,6673,6674,6675,6676,6677,6678,6679,6680,6681,6682,6683,
6684,6685,6686,6687,6688,6689,6690,6691,6692,6693,6694,6695,6696,6697,6698,
6699,6700,6701,6702,6703,6704,6705,6706,6707,6708,6709,6710,6711,6712,6713,
6714,6715,6716,6717,6718,6719,6720,6721,6722,6723,6724,6725,6726,6727,6728,
6729,6730,6731,6732,6733,6734,6735,6736,6737,6738,6739,6740,6741,6742,6743,
6744,6745,6746,6747,6748,6749,6750,6751,6752,6753,6754,6755,6756,6757,6758,
6759,6760,6761,6762,6763,6764,6765,6766,6767,6768,6769,6770,6771,6772,6773,
6774,6775,6776,6777,6778,6779,6780,6781,6782,6783,6784,6785,6786,6787,6788,
6789,6790,6791,6792,6793,6794,6795,6796,6797,6798,6799,6800,6801,6802,6803,
6804,6805,6806,6807,6808,6809,6810,6811,6812,6813,6814,6815,6816,6817,6818,
6819,6820,6821,6822,6823,6824,6825,6826,6827,6828,6829,6830,6831,6832,6833,
6834,6835,6836,6837,6838,6839,6840,6841,6842,6843,6844,6845,6846,6847,6848,
6849,6850,6851,6852,6853,6854,6855,6856,6857,6858,6859,6860,6861,6862,6863,
6864,6865,6866,6867,6868,6869,6870,6871,6872,6873,6874,6875,6876,6877,6878,
6879,6880,6881,6882,6883,6884,6885,6886,6887,6888,6889,6890,6891,6892,6893,
6894,6895,6896,6897,6898,6899,6900,6901,6902,6903,6904,6905,6906,6907,6908,
6909,6910,6911,6912,6913,6914,6915,6916,6917,6918,6919,6920,6921,6922,6923,
6924,6925,6926,6927,6928,6929,6930,6931,6932,6933,6934,6935,6936,6937,6938,
6939,6940,6941,6942,6943,6944,6945,6946,6947,6948,6949,6950,6951,6952,6953,
6954,6955,6956,6957,6958,6959,6960,6961,6962,6963,6964,6965,6966,6967,6968,
6969,6970,6971,6972,6973,6974,6975,6976,6977,6978,6979,6980,6981,6982,6983,
6984,6985,6986,6987,6988,6989,6990,6991,6992,6993,6994,6995,6996,6997,6998,
6999,7000,7001,7002,7003,7004,7005,7006,7007,7008,7009,7010,7011,7012,7013,
7014,7015,7016,7017,7018,7019,7020,7021,7022,7023,7024,7025,7026,7027,7028,
7029,7030,7031,7032,7033,7034,7035,7036,7037,7038,7039,7040,7041,7042,7043,
7044,7045,7046,7047,7048,7049,7050,7051,7052,7053,7054,7055,7056,7057,7058,
7059,7060,7061,7062,7063,7064,7065,7066,7067,7068,7069,7070,7071,7072,7073,
7074,7075,7076,7077,7078,7079,7080,7081,7082,7083,7084,7085,7086,7087,7088,
7089,7090,7091,7092,7093,7094,7095,7096,7097,7098,7099,7100,7101,7102,7103,
7104,7105,7106,7107,7108,7109,7110,7111,7112,7113,7114,7115,7116,7117,7118,
7119,7120,7121,7122,7123,7124,7125,7126,7127,7128,7129,7130,7131,7132,7133,
7134,7135,7136,7137,7138,7139,7140,7141,7142,7143,7144,7145,7146,7147,7148,
7149,7150,7151,7152,7153,7154,7155,7156,7157,7158,7159,7160,7161,7162,7163,
7164,7165,7166,7167,7168,7169,7170,7171,7172,7173,7174,7175,7176,7177,7178,
7179,7180,7181,7182,7183,7184,7185,7186,7187,7188,7189,7190,7191,7192,7193,
7194,7195,7196,7197,7198,7199,7200,7201,7202,7203,7204,7205,7206,7207,7208,
7209,7210,7211,7212,7213,7214,7215,7216,7217,7218,7219,7220,7221,7222,7223,
7224,7225,7226,7227,7228,7229,7230,7231,7232,7233,7234,7235,7236,7237,7238,
7239,7240,7241,7242,7243,7244,7245,7246,7247,7248,7249,7250,7251,7252,7253,
7254,7255,7256,7257,7258,7259,7260,7261,7262,7263,7264,7265,7266,7267,7268,
7269,7270,7271,7272,7273,7274,7275,7276,7277,7278,7279,7280,7281,7282,7283,
7284,7285,7286,7287,7288,7289,7290,7291,7292,7293,7294,7295,1042,1044,1054,
1057,1058,1058,1066,1122,42570L,7305,7306,7307,7308,7309,7310,7311,7312,
7313,7314,7315,7316,7317,7318,7319,7320,7321,7322,7323,7324,7325,7326,7327,
7328,7329,7330,7331,7332,7333,7334,7335,7336,7337,7338,7339,7340,7341,7342,
7343,7344,7345,7346,7347,7348,7349,7350,7351,7352,7353,7354,7355,7356,7357,
7358,7359,7360,7361,7362,7363,7364,7365,7366,7367,7368,7369,7370,7371,7372,
7373,7374,7375,7376,7377,7378,7379,7380,7381,7382,7383,7384,7385,7386,7387,
7388,7389,7390,7391,7392,7393,7394,7395,7396,7397,7398,7399,7400,7401,7402,
7403,7404,7405,7406,7407,7408,7409,7410,7411,7412,7413,7414,7415,7416,7417,
7418,7419,7420,7421,7422,7423,7424,7425,7426,7427,7428,7429,7430,7431,7432,
7433,7434,7435,7436,7437,7438,7439,7440,7441,7442,7443,7444,7445,7446,7447,
7448,7449,7450,7451,7452,7453,7454,7455,7456,7457,7458,7459,7460,7461,7462,
7463,7464,7465,7466,7467,7468,7469,7470,7471,7472,7473,7474,7475,7476,7477,
7478,7479,7480,7481,7482,7483,7484,7485,7486,7487,7488,7489,7490,7491,7492,
7493,7494,7495,7496,7497,7498,7499,7500,7501,7502,7503,7504,7505,7506,7507,
7508,7509,7510,7511,7512,7513,7514,7515,7516,7517,7518,7519,7520,7521,7522,
7523,7524,7525,7526,7527,7528,7529,7530,7531,7532,7533,7534,7535,7536,7537,
7538,7539,7540,7541,7542,7543,7544,42877L,7546,7547,7548,11363,7550,7551,
7552,7553,7554,7555,7556,7557,7558,7559,7560,7561,7562,7563,7564,7565,
42950L,7567,7568,7569,7570,7571,7572,7573,7574,7575,7576,7577,7578,7579,
7580,7581,7582,7583,7584,7585,7586,7587,7588,7589,7590,7591,7592,7593,7594,
7595,7596,7597,7598,7599,7600,7601,7602,7603,7604,7605,7606,7607,7608,7609,
7610,7611,7612,7613,7614,7615,7616,7617,7618,7619,7620,7621,7622,7623,7624,
7625,7626,7627,7628,7629,7630,7631,7632,7633,7634,7635,7636,7637,7638,7639,
7640,7641,7642,7643,7644,7645,7646,7647,7648,7649,7650,7651,7652,7653,7654,
7655,7656,7657,7658,7659,7660,7661,7662,7663,7664,7665,7666,7667,7668,7669,
7670,7671,7672,7673,7674,7675,7676,7677,7678,7679,7680,7680,7682,7682,7684,
7684,7686,7686,7688,7688,7690,7690,7692,7692,7694,7694,7696,7696,7698,7698,
7700,7700,7702,7702,7704,7704,7706,7706,7708,7708,7710,7710,7712,7712,7714,
7714,7716,7716,7718,7718,7720,7720,7722,7722,7724,7724,7726,7726,7728,7728,
7730,7730,7732,7732,7734,7734,7736,7736,7738,7738,7740,7740,7742,7742,7744,
7744,7746,7746,7748,7748,7750,7750,7752,7752,7754,7754,7756,7756,7758,7758,
7760,7760,7762,7762,7764,7764,7766,7766,7768,7768,7770,7770,7772,7772,7774,
7774,7776,7776,7778,7778,7780,7780,7782,7782,7784,7784,7786,7786,7788,7788,
7790,7790,7792,7792,7794,7794,7796,7796,7798,7798,7800,7800,7802,7802,7804,
7804,7806,7806,7808,7808,7810,7810,7812,7812,7814,7814,7816,7816,7818,7818,
7820,7820,7822,7822,7824,7824,7826,7826,7828,7828,7830,7831,7832,7833,7834,
7776,7836,7837,7838,7839,7840,7840,7842,7842,7844,7844,7846,7846,7848,7848,
7850,7850,7852,7852,7854,7854,7856,7856,7858,7858,7860,7860,7862,7862,7864,
7864,7866,7866,7868,7868,7870,7870,7872,7872,7874,7874,7876,7876,7878,7878,
7880,7880,7882,7882,7884,7884,7886,7886,7888,7888,7890,7890,7892,7892,7894,
7894,7896,7896,7898,7898,7900,7900,7902,7902,7904,7904,7906,7906,7908,7908,
7910,7910,7912,7912,7914,7914,7916,7916,7918,7918,7920,7920,7922,7922,7924,
7924,7926,7926,7928,7928,7930,7930,7932,7932,7934,7934,7944,7945,7946,7947,
7948,7949,7950,7951,7944,7945,7946,7947,7948,7949,7950,7951,7960,7961,7962,
7963,7964,7965,7958,7959,7960,7961,7962,7963,7964,7965,7966,7967,7976,7977,
7978,7979,7980,7981,7982,7983,7976,7977,7978,7979,7980,7981,7982,7983,7992,
7993,7994,7995,7996,7997,7998,7999,7992,7993,7994,7995,7996,7997,7998,7999,
8008,8009,8010,8011,8012,8013,8006,8007,8008,8009,8010,8011,8012,8013,8014,
8015,8016,8025,8018,8027,8020,8029,8022,8031,8024,8025,8026,8027,8028,8029,
8030,8031,8040,8041,8042,8043,8044,8045,8046,8047,8040,8041,8042,8043,8044,
8045,8046,8047,8122,8123,8136,8137,8138,8139,8154,8155,8184,8185,8170,8171,
8186,8187,8062,8063,8064,8065,8066,8067,8068,8069,8070,8071,8072,8073,8074,
8075,8076,8077,8078,8079,8080,8081,8082,8083,8084,8085,8086,8087,8088,8089,
8090,8091,8092,8093,8094,8095,8096,8097,8098,8099,8100,8101,8102,8103,8104,
8105,8106,8107,8108,8109,8110,8111,8120,8121,8114,8115,8116,8117,8118,8119,
8120,8121,8122,8123,8124,8125,921,8127,8128,8129,8130,8131,8132,8133,8134,
8135,8136,8137,8138,8139,8140,8141,8142,8143,8152,8153,8146,8147,8148,8149,
8150,8151,8152,8153,8154,8155,8156,8157,8158,8159,8168,8169,8162,8163,8164,
8172,8166,8167,8168,8169,8170,8171,8172,8173,8174,8175,8176,8177,8178,8179,
8180,8181,8182,8183,8184,8185,8186,8187,8188,8189,8190,8191,8192,8193,8194,
8195,8196,8197,8198,8199,8200,8201,8202,8203,8204,8205,8206,8207,8208,8209,
8210,8211,8212,8213,8214,8215,8216,8217,8218,8219,8220,8221,8222,8223,8224,
8225,8226,8227,8228,8229,8230,8231,8232,8233,8234,8235,8236,8237,8238,8239,
8240,8241,8242,8243,8244,8245,8246,8247,8248,8249,8250,8251,8252,8253,8254,
8255,8256,8257,8258,8259,8260,8261,8262,8263,8264,8265,8266,8267,8268,8269,
8270,8271,8272,8273,8274,8275,8276,8277,8278,8279,8280,8281,8282,8283,8284,
8285,8286,8287,8288,8289,8290,8291,8292,8293,8294,8295,8296,8297,8298,8299,
8300,8301,8302,8303,8304,8305,8306,8307,8308,8309,8310,8311,8312,8313,8314,
8315,8316,8317,8318,8319,8320,8321,8322,8323,8324,8325,8326,8327,8328,8329,
8330,8331,8332,8333,8334,8335,8336,8337,8338,8339,8340,8341,8342,8343,8344,
8345,8346,8347,8348,8349,8350,8351,8352,8353,8354,8355,8356,8357,8358,8359,
8360,8361,8362,8363,8364,8365,8366,8367,8368,8369,8370,8371,8372,8373,8374,
8375,8376,8377,8378,8379,8380,8381,8382,8383,8384,8385,8386,8387,8388,8389,
8390,8391,8392,8393,8394,8395,8396,8397,8398,8399,8400,8401,8402,8403,8404,
8405,8406,8407,8408,8409,8410,8411,8412,8413,8414,8415,8416,8417,8418,8419,
8420,8421,8422,8423,8424,8425,8426,8427,8428,8429,8430,8431,8432,8433,8434,
8435,8436,8437,8438,8439,8440,8441,8442,8443,8444,8445,8446,8447,8448,8449,
8450,8451,8452,8453,8454,8455,8456,8457,8458,8459,8460,8461,8462,8463,8464,
8465,8466,8467,8468,8469,8470,8471,8472,8473,8474,8475,8476,8477,8478,8479,
8480,8481,8482,8483,8484,8485,8486,8487,8488,8489,8490,8491,8492,8493,8494,
8495,8496,8497,8498,8499,8500,8501,8502,8503,8504,8505,8506,8507,8508,8509,
8510,8511,8512,8513,8514,8515,8516,8517,8518,8519,8520,8521,8522,8523,8524,
8525,8498,8527,8528,8529,8530,8531,8532,8533,8534,8535,8536,8537,8538,8539,
8540,8541,8542,8543,8544,8545,8546,8547,8548,8549,8550,8551,8552,8553,8554,
8555,8556,8557,8558,8559,8544,8545,8546,8547,8548,8549,8550,8551,8552,8553,
8554,8555,8556,8557,8558,8559,8576,8577,8578,8579,8579,8581,8582,8583,8584,
8585,8586,8587,8588,8589,8590,8591,8592,8593,8594,8595,8596,8597,8598,8599,
8600,8601,8602,8603,8604,8605,8606,8607,8608,8609,8610,8611,8612,8613,8614,
8615,8616,8617,8618,8619,8620,8621,8622,8623,8624,8625,8626,8627,8628,8629,
8630,8631,8632,8633,8634,8635,8636,8637,8638,8639,8640,8641,8642,8643,8644,
8645,8646,8647,8648,8649,8650,8651,8652,8653,8654,8655,8656,8657,8658,8659,
8660,8661,8662,8663,8664,8665,8666,8667,8668,8669,8670,8671,8672,8673,8674,
8675,8676,8677,8678,8679,8680,8681,8682,8683,8684,8685,8686,8687,8688,8689,
8690,8691,8692,8693,8694,8695,8696,8697,8698,8699,8700,8701,8702,8703,8704,
8705,8706,8707,8708,8709,8710,8711,8712,8713,8714,8715,8716,8717,8718,8719,
8720,8721,8722,8723,8724,8725,8726,8727,8728,8729,8730,8731,8732,8733,8734,
8735,8736,8737,8738,8739,8740,8741,8742,8743,8744,8745,8746,8747,8748,8749,
8750,8751,8752,8753,8754,8755,8756,8757,8758,8759,8760,8761,8762,8763,8764,
8765,8766,8767,8768,8769,8770,8771,8772,8773,8774,8775,8776,8777,8778,8779,
8780,8781,8782,8783,8784,8785,8786,8787,8788,8789,8790,8791,8792,8793,8794,
8795,8796,8797,8798,8799,8800,8801,8802,8803,8804,8805,8806,8807,8808,8809,
8810,8811,8812,8813,8814,8815,8816,8817,8818,8819,8820,8821,8822,8823,8824,
8825,8826,8827,8828,8829,8830,8831,8832,8833,8834,8835,8836,8837,8838,8839,
8840,8841,8842,8843,8844,8845,8846,8847,8848,8849,8850,8851,8852,8853,8854,
8855,8856,8857,8858,8859,8860,8861,8862,8863,8864,8865,8866,8867,8868,8869,
8870,8871,8872,8873,8874,8875,8876,8877,8878,8879,8880,8881,8882,8883,8884,
8885,8886,8887,8888,8889,8890,8891,8892,8893,8894,8895,8896,8897,8898,8899,
8900,8901,8902,8903,8904,8905,8906,8907,8908,8909,8910,8911,8912,8913,8914,
8915,8916,8917,8918,8919,8920,8921,8922,8923,8924,8925,8926,8927,8928,8929,
8930,8931,8932,8933,8934,8935,8936,8937,8938,8939,8940,8941,8942,8943,8944,
8945,8946,8947,8948,8949,8950,8951,8952,8953,8954,8955,8956,8957,8958,8959,
8960,8961,8962,8963,8964,8965,8966,8967,8968,8969,8970,8971,8972,8973,8974,
8975,8976,8977,8978,8979,8980,8981,8982,8983,8984,8985,8986,8987,8988,8989,
8990,8991,8992,8993,8994,8995,8996,8997,8998,8999,9000,9001,9002,9003,9004,
9005,9006,9007,9008,9009,9010,9011,9012,9013,9014,9015,9016,9017,9018,9019,
9020,9021,9022,9023,9024,9025,9026,9027,9028,9029,9030,9031,9032,9033,9034,
9035,9036,9037,9038,9039,9040,9041,9042,9043,9044,9045,9046,9047,9048,9049,
9050,9051,9052,9053,9054,9055,9056,9057,9058,9059,9060,9061,9062,9063,9064,
9065,9066,9067,9068,9069,9070,9071,9072,9073,9074,9075,9076,9077,9078,9079,
9080,9081,9082,9083,9084,9085,9086,9087,9088,9089,9090,9091,9092,9093,9094,
9095,9096,9097,9098,9099,9100,9101,9102,9103,9104,9105,9106,9107,9108,9109,
9110,9111,9112,9113,9114,9115,9116,9117,9118,9119,9120,9121,9122,9123,9124,
9125,9126,9127,9128,9129,9130,9131,9132,9133,9134,9135,9136,9137,9138,9139,
9140,9141,9142,9143,9144,9145,9146,9147,9148,9149,9150,9151,9152,9153,9154,
9155,9156,9157,9158,9159,9160,9161,9162,9163,9164,9165,9166,9167,9168,9169,
9170,9171,9172,9173,9174,9175,9176,9177,9178,9179,9180,9181,9182,9183,9184,
9185,9186,9187,9188,9189,9190,9191,9192,9193,9194,9195,9196,9197,9198,9199,
9200,9201,9202,9203,9204,9205,9206,9207,9208,9209,9210,9211,9212,9213,9214,
9215,9216,9217,9218,9219,9220,9221,9222,9223,9224,9225,9226,9227,9228,9229,
9230,9231,9232,9233,9234,9235,9236,9237,9238,9239,9240,9241,9242,9243,9244,
9245,9246,9247,9248,9249,9250,9251,9252,9253,9254,9255,9256,9257,9258,9259,
9260,9261,9262,9263,9264,9265,9266,9267,9268,9269,9270,9271,9272,9273,9274,
9275,9276,9277,9278,9279,9280,9281,9282,9283,9284,9285,9286,9287,9288,9289,
9290,9291,9292,9293,9294,9295,9296,9297,9298,9299,9300,9301,9302,9303,9304,
9305,9306,9307,9308,9309,9310,9311,9312,9313,9314,9315,9316,9317,9318,9319,
9320,9321,9322,9323,9324,9325,9326,9327,9328,9329,9330,9331,9332,9333,9334,
9335,9336,9337,9338,9339,9340,9341,9342,9343,9344,9345,9346,9347,9348,9349,
9350,9351,9352,9353,9354,9355,9356,9357,9358,9359,9360,9361,9362,9363,9364,
9365,9366,9367,9368,9369,9370,9371,9372,9373,9374,9375,9376,9377,9378,9379,
9380,9381,9382,9383,9384,9385,9386,9387,9388,9389,9390,9391,9392,9393,9394,
9395,9396,9397,9398,9399,9400,9401,9402,9403,9404,9405,9406,9407,9408,9409,
9410,9411,9412,9413,9414,9415,9416,9417,9418,9419,9420,9421,9422,9423,9398,
9399,9400,9401,9402,9403,9404,9405,9406,9407,9408,9409,9410,9411,9412,9413,
9414,9415,9416,9417,9418,9419,9420,9421,9422,9423,9450,9451,9452,9453,9454,
9455,9456,9457,9458,9459,9460,9461,9462,9463,9464,9465,9466,9467,9468,9469,
9470,9471,9472,9473,9474,9475,9476,9477,9478,9479,9480,9481,9482,9483,9484,
9485,9486,9487,9488,9489,9490,9491,9492,9493,9494,9495,9496,9497,9498,9499,
9500,9501,9502,9503,9504,9505,9506,9507,9508,9509,9510,9511,9512,9513,9514,
9515,9516,9517,9518,9519,9520,9521,9522,9523,9524,9525,9526,9527,9528,9529,
9530,9531,9532,9533,9534,9535,9536,9537,9538,9539,9540,9541,9542,9543,9544,
9545,9546,9547,9548,9549,9550,9551,9552,9553,9554,9555,9556,9557,9558,9559,
9560,9561,9562,9563,9564,9565,9566,9567,9568,9569,9570,9571,9572,9573,9574,
9575,9576,9577,9578,9579,9580,9581,9582,9583,9584,9585,9586,9587,9588,9589,
9590,9591,9592,9593,9594,9595,9596,9597,9598,9599,9600,9601,9602,9603,9604,
9605,9606,9607,9608,9609,9610,9611,9612,9613,9614,9615,9616,9617,9618,9619,
9620,9621,9622,9623,9624,9625,9626,9627,9628,9629,9630,9631,9632,9633,9634,
9635,9636,9637,9638,9639,9640,9641,9642,9643,9644,9645,9646,9647,9648,9649,
9650,9651,9652,9653,9654,9655,9656,9657,9658,9659,9660,9661,9662,9663,9664,
9665,9666,9667,9668,9669,9670,9671,9672,9673,9674,9675,9676,9677,9678,9679,
9680,9681,9682,9683,9684,9685,9686,9687,9688,9689,9690,9691,9692,9693,9694,
9695,9696,9697,9698,9699,9700,9701,9702,9703,9704,9705,9706,9707,9708,9709,
9710,9711,9712,9713,9714,9715,9716,9717,9718,9719,9720,9721,9722,9723,9724,
9725,9726,9727,9728,9729,9730,9731,9732,9733,9734,9735,9736,9737,9738,9739,
9740,9741,9742,9743,9744,9745,9746,9747,9748,9749,9750,9751,9752,9753,9754,
9755,9756,9757,9758,9759,9760,9761,9762,9763,9764,9765,9766,9767,9768,9769,
9770,9771,9772,9773,9774,9775,9776,9777,9778,9779,9780,9781,9782,9783,9784,
9785,9786,9787,9788,9789,9790,9791,9792,9793,9794,9795,9796,9797,9798,9799,
9800,9801,9802,9803,9804,9805,9806,9807,9808,9809,9810,9811,9812,9813,9814,
9815,9816,9817,9818,9819,9820,9821,9822,9823,9824,9825,9826,9827,9828,9829,
9830,9831,9832,9833,9834,9835,9836,9837,9838,9839,9840,9841,9842,9843,9844,
9845,9846,9847,9848,9849,9850,9851,9852,9853,9854,9855,9856,9857,9858,9859,
9860,9861,9862,9863,9864,9865,9866,9867,9868,9869,9870,9871,9872,9873,9874,
9875,9876,9877,9878,9879,9880,9881,9882,9883,9884,9885,9886,9887,9888,9889,
9890,9891,9892,9893,9894,9895,9896,9897,9898,9899,9900,9901,9902,9903,9904,
9905,9906,9907,9908,9909,9910,9911,9912,9913,9914,9915,9916,9917,9918,9919,
9920,9921,9922,9923,9924,9925,9926,9927,9928,9929,9930,9931,9932,9933,9934,
9935,9936,9937,9938,9939,9940,9941,9942,9943,9944,9945,9946,9947,9948,9949,
9950,9951,9952,9953,9954,9955,9956,9957,9958,9959,9960,9961,9962,9963,9964,
9965,9966,9967,9968,9969,9970,9971,9972,9973,9974,9975,9976,9977,9978,9979,
9980,9981,9982,9983,9984,9985,9986,9987,9988,9989,9990,9991,9992,9993,9994,
9995,9996,9997,9998,9999,10000,10001,10002,10003,10004,10005,10006,10007,
10008,10009,10010,10011,10012,10013,10014,10015,10016,10017,10018,10019,
10020,10021,10022,10023,10024,10025,10026,10027,10028,10029,10030,10031,
10032,10033,10034,10035,10036,10037,10038,10039,10040,10041,10042,10043,
10044,10045,10046,10047,10048,10049,10050,10051,10052,10053,10054,10055,
10056,10057,10058,10059,10060,10061,10062,10063,10064,10065,10066,10067,
10068,10069,10070,10071,10072,10073,10074,10075,10076,10077,10078,10079,
10080,10081,10082,10083,10084,10085,10086,10087,10088,10089,10090,10091,
10092,10093,10094,10095,10096,10097,10098,10099,10100,10101,10102,10103,
10104,10105,10106,10107,10108,10109,10110,10111,10112,10113,10114,10115,
10116,10117,10118,10119,10120,10121,10122,10123,10124,10125,10126,10127,
10128,10129,10130,10131,10132,10133,10134,10135,10136,10137,10138,10139,
10140,10141,10142,10143,10144,10145,10146,10147,10148,10149,10150,10151,
10152,10153,10154,10155,10156,10157,10158,10159,10160,10161,10162,10163,
10164,10165,10166,10167,10168,10169,10170,10171,10172,10173,10174,10175,
10176,10177,10178,10179,10180,10181,10182,10183,10184,10185,10186,10187,
10188,10189,10190,10191,10192,10193,10194,10195,10196,10197,10198,10199,
10200,10201,10202,10203,10204,10205,10206,10207,10208,10209,10210,10211,
10212,10213,10214,10215,10216,10217,10218,10219,10220,10221,10222,10223,
10224,10225,10226,10227,10228,10229,10230,10231,10232,10233,10234,10235,
10236,10237,10238,10239,10240,10241,10242,10243,10244,10245,10246,10247,
10248,10249,10250,10251,10252,10253,10254,10255,10256,10257,10258,10259,
10260,10261,10262,10263,10264,10265,10266,10267,10268,10269,10270,10271,
10272,10273,10274,10275,10276,10277,10278,10279,10280,10281,10282,10283,
10284,10285,10286,10287,10288,10289,10290,10291,10292,10293,10294,10295,
10296,10297,10298,10299,10300,10301,10302,10303,10304,10305,10306,10307,
10308,10309,10310,10311,10312,10313,10314,10315,10316,10317,10318,10319,
10320,10321,10322,10323,10324,10325,10326,10327,10328,10329,10330,10331,
10332,10333,10334,10335,10336,10337,10338,10339,10340,10341,10342,10343,
10344,10345,10346,10347,10348,10349,10350,10351,10352,10353,10354,10355,
10356,10357,10358,10359,10360,10361,10362,10363,10364,10365,10366,10367,
10368,10369,10370,10371,10372,10373,10374,10375,10376,10377,10378,10379,
10380,10381,10382,10383,10384,10385,10386,10387,10388,10389,10390,10391,
10392,10393,10394,10395,10396,10397,10398,10399,10400,10401,10402,10403,
10404,10405,10406,10407,10408,10409,10410,10411,10412,10413,10414,10415,
10416,10417,10418,10419,10420,10421,10422,10423,10424,10425,10426,10427,
10428,10429,10430,10431,10432,10433,10434,10435,10436,10437,10438,10439,
10440,10441,10442,10443,10444,10445,10446,10447,10448,10449,10450,10451,
10452,10453,10454,10455,10456,10457,10458,10459,10460,10461,10462,10463,
10464,10465,10466,10467,10468,10469,10470,10471,10472,10473,10474,10475,
10476,10477,10478,10479,10480,10481,10482,10483,10484,10485,10486,10487,
10488,10489,10490,10491,10492,10493,10494,10495,10496,10497,10498,10499,
10500,10501,10502,10503,10504,10505,10506,10507,10508,10509,10510,10511,
10512,10513,10514,10515,10516,10517,10518,10519,10520,10521,10522,10523,
10524,10525,10526,10527,10528,10529,10530,10531,10532,10533,10534,10535,
10536,10537,10538,10539,10540,10541,10542,10543,10544,10545,10546,10547,
10548,10549,10550,10551,10552,10553,10554,10555,10556,10557,10558,10559,
10560,10561,10562,10563,10564,10565,10566,10567,10568,10569,10570,10571,
10572,10573,10574,10575,10576,10577,10578,10579,10580,10581,10582,10583,
10584,10585,10586,10587,10588,10589,10590,10591,10592,10593,10594,10595,
10596,10597,10598,10599,10600,10601,10602,10603,10604,10605,10606,10607,
10608,10609,10610,10611,10612,10613,10614,10615,10616,10617,10618,10619,
10620,10621,10622,10623,10624,10625,10626,10627,10628,10629,10630,10631,
10632,10633,10634,10635,10636,10637,10638,10639,10640,10641,10642,10643,
10644,10645,10646,10647,10648,10649,10650,10651,10652,10653,10654,10655,
10656,10657,10658,10659,10660,10661,10662,10663,10664,10665,10666,10667,
10668,10669,10670,10671,10672,10673,10674,10675,10676,10677,10678,10679,
10680,10681,10682,10683,10684,10685,10686,10687,10688,10689,10690,10691,
10692,10693,10694,10695,10696,10697,10698,10699,10700,10701,10702,10703,
10704,10705,10706,10707,10708,10709,10710,10711,10712,10713,10714,10715,
10716,10717,10718,10719,10720,10721,10722,10723,10724,10725,10726,10727,
10728,10729,10730,10731,10732,10733,10734,10735,10736,10737,10738,10739,
10740,10741,10742,10743,10744,10745,10746,10747,10748,10749,10750,10751,
10752,10753,10754,10755,10756,10757,10758,10759,10760,10761,10762,10763,
10764,10765,10766,10767,10768,10769,10770,10771,10772,10773,10774,10775,
10776,10777,10778,10779,10780,10781,10782,10783,10784,10785,10786,10787,
10788,10789,10790,10791,10792,10793,10794,10795,10796,10797,10798,10799,
10800,10801,10802,10803,10804,10805,10806,10807,10808,10809,10810,10811,
10812,10813,10814,10815,10816,10817,10818,10819,10820,10821,10822,10823,
10824,10825,10826,10827,10828,10829,10830,10831,10832,10833,10834,10835,
10836,10837,10838,10839,10840,10841,10842,10843,10844,10845,10846,10847,
10848,10849,10850,10851,10852,10853,10854,10855,10856,10857,10858,10859,
10860,10861,10862,10863,10864,10865,10866,10867,10868,10869,10870,10871,
10872,10873,10874,10875,10876,10877,10878,10879,10880,10881,10882,10883,
10884,10885,10886,10887,10888,10889,10890,10891,10892,10893,10894,10895,
10896,10897,10898,10899,10900,10901,10902,10903,10904,10905,10906,10907,
10908,10909,10910,10911,10912,10913,10914,10915,10916,10917,10918,10919,
10920,10921,10922,10923,10924,10925,10926,10927,10928,10929,10930,10931,
10932,10933,10934,10935,10936,10937,10938,10939,10940,10941,10942,10943,
10944,10945,10946,10947,10948,10949,10950,10951,10952,10953,10954,10955,
10956,10957,10958,10959,10960,10961,10962,10963,10964,10965,10966,10967,
10968,10969,10970,10971,10972,10973,10974,10975,10976,10977,10978,10979,
10980,10981,10982,10983,10984,10985,10986,10987,10988,10989,10990,10991,
10992,10993,10994,10995,10996,10997,10998,10999,11000,11001,11002,11003,
11004,11005,11006,11007,11008,11009,11010,11011,11012,11013,11014,11015,
11016,11017,11018,11019,11020,11021,11022,11023,11024,11025,11026,11027,
11028,11029,11030,11031,11032,11033,11034,11035,11036,11037,11038,11039,
11040,11041,11042,11043,11044,11045,11046,11047,11048,11049,11050,11051,
11052,11053,11054,11055,11056,11057,11058,11059,11060,11061,11062,11063,
11064,11065,11066,11067,11068,11069,11070,11071,11072,11073,11074,11075,
11076,11077,11078,11079,11080,11081,11082,11083,11084,11085,11086,11087,
11088,11089,11090,11091,11092,11093,11094,11095,11096,11097,11098,11099,
11100,11101,11102,11103,11104,11105,11106,11107,11108,11109,11110,11111,
11112,11113,11114,11115,11116,11117,11118,11119,11120,11121,11122,11123,
11124,11125,11126,11127,11128,11129,11130,11131,11132,11133,11134,11135,
11136,11137,11138,11139,11140,11141,11142,11143,11144,11145,11146,11147,
11148,11149,11150,11151,11152,11153,11154,11155,11156,11157,11158,11159,
11160,11161,11162,11163,11164,11165,11166,11167,11168,11169,11170,11171,
11172,11173,11174,11175,11176,11177,11178,11179,11180,11181,11182,11183,
11184,11185,11186,11187,11188,11189,11190,11191,11192,11193,11194,11195,
11196,11197,11198,11199,11200,11201,11202,11203,11204,11205,11206,11207,
11208,11209,11210,11211,11212,11213,11214,11215,11216,11217,11218,11219,
11220,11221,11222,11223,11224,11225,11226,11227,11228,11229,11230,11231,
11232,11233,11234,11235,11236,11237,11238,11239,11240,11241,11242,11243,
11244,11245,11246,11247,11248,11249,11250,11251,11252,11253,11254,11255,
11256,11257,11258,11259,11260,11261,11262,11263,11264,11265,11266,11267,
11268,11269,11270,11271,11272,11273,11274,11275,11276,11277,11278,11279,
11280,11281,11282,11283,11284,11285,11286,11287,11288,11289,11290,11291,
11292,11293,11294,11295,11296,11297,11298,11299,11300,11301,11302,11303,
11304,11305,11306,11307,11308,11309,11310,11311,11264,11265,11266,11267,
11268,11269,11270,11271,11272,11273,11274,11275,11276,11277,11278,11279,
11280,11281,11282,11283,11284,11285,11286,11287,11288,11289,11290,11291,
11292,11293,11294,11295,11296,11297,11298,11299,11300,11301,11302,11303,
11304,11305,11306,11307,11308,11309,11310,11359,11360,11360,11362,11363,
11364,570,574,11367,11367,11369,11369,11371,11371,11373,11374,11375,11376,
11377,11378,11378,11380,11381,11381,11383,11384,11385,11386,11387,11388,
11389,11390,11391,11392,11392,11394,11394,11396,11396,11398,11398,11400,
11400,11402,11402,11404,11404,11406,11406,11408,11408,11410,11410,11412,
11412,11414,11414,11416,11416,11418,11418,11420,11420,11422,11422,11424,
11424,11426,11426,11428,11428,11430,11430,11432,11432,11434,11434,11436,
11436,11438,11438,11440,11440,11442,11442,11444,11444,11446,11446,11448,
11448,11450,11450,11452,11452,11454,11454,11456,11456,11458,11458,11460,
11460,11462,11462,11464,11464,11466,11466,11468,11468,11470,11470,11472,
11472,11474,11474,11476,11476,11478,11478,11480,11480,11482,11482,11484,
11484,11486,11486,11488,11488,11490,11490,11492,11493,11494,11495,11496,
11497,11498,11499,11499,11501,11501,11503,11504,11505,11506,11506,11508,
11509,11510,11511,11512,11513,11514,11515,11516,11517,11518,11519,4256,
4257,4258,4259,4260,4261,4262,4263,4264,4265,4266,4267,4268,4269,4270,4271,
4272,4273,4274,4275,4276,4277,4278,4279,4280,4281,4282,4283,4284,4285,4286,
4287,4288,4289,4290,4291,4292,4293,11558,4295,11560,11561,11562,11563,
11564,4301,11566,11567,11568,11569,11570,11571,11572,11573,11574,11575,
11576,11577,11578,11579,11580,11581,11582,11583,11584,11585,11586,11587,
11588,11589,11590,11591,11592,11593,11594,11595,11596,11597,11598,11599,
11600,11601,11602,11603,11604,11605,11606,11607,11608,11609,11610,11611,
11612,11613,11614,11615,11616,11617,11618,11619,11620,11621,11622,11623,
11624,11625,11626,11627,11628,11629,11630,11631,11632,11633,11634,11635,
11636,11637,11638,11639,11640,11641,11642,11643,11644,11645,11646,11647,
11648,11649,11650,11651,11652,11653,11654,11655,11656,11657,11658,11659,
11660,11661,11662,11663,11664,11665,11666,11667,11668,11669,11670,11671,
11672,11673,11674,11675,11676,11677,11678,11679,11680,11681,11682,11683,
11684,11685,11686,11687,11688,11689,11690,11691,11692,11693,11694,11695,
11696,11697,11698,11699,11700,11701,11702,11703,11704,11705,11706,11707,
11708,11709,11710,11711,11712,11713,11714,11715,11716,11717,11718,11719,
11720,11721,11722,11723,11724,11725,11726,11727,11728,11729,11730,11731,
11732,11733,11734,11735,11736,11737,11738,11739,11740,11741,11742,11743,
11744,11745,11746,11747,11748,11749,11750,11751,11752,11753,11754,11755,
11756,11757,11758,11759,11760,11761,11762,11763,11764,11765,11766,11767,
11768,11769,11770,11771,11772,11773,11774,11775,11776,11777,11778,11779,
11780,11781,11782,11783,11784,11785,11786,11787,11788,11789,11790,11791,
11792,11793,11794,11795,11796,11797,11798,11799,11800,11801,11802,11803,
11804,11805,11806,11807,11808,11809,11810,11811,11812,11813,11814,11815,
11816,11817,11818,11819,11820,11821,11822,11823,11824,11825,11826,11827,
11828,11829,11830,11831,11832,11833,11834,11835,11836,11837,11838,11839,
11840,11841,11842,11843,11844,11845,11846,11847,11848,11849,11850,11851,
11852,11853,11854,11855,11856,11857,11858,11859,11860,11861,11862,11863,
11864,11865,11866,11867,11868,11869,11870,11871,11872,11873,11874,11875,
11876,11877,11878,11879,11880,11881,11882,11883,11884,11885,11886,11887,
11888,11889,11890,11891,11892,11893,11894,11895,11896,11897,11898,11899,
11900,11901,11902,11903,11904,11905,11906,11907,11908,11909,11910,11911,
11912,11913,11914,11915,11916,11917,11918,11919,11920,11921,11922,11923,
11924,11925,11926,11927,11928,11929,11930,11931,11932,11933,11934,11935,
11936,11937,11938,11939,11940,11941,11942,11943,11944,11945,11946,11947,
11948,11949,11950,11951,11952,11953,11954,11955,11956,11957,11958,11959,
11960,11961,11962,11963,11964,11965,11966,11967,11968,11969,11970,11971,
11972,11973,11974,11975,11976,11977,11978,11979,11980,11981,11982,11983,
11984,11985,11986,11987,11988,11989,11990,11991,11992,11993,11994,11995,
11996,11997,11998,11999,12000,12001,12002,12003,12004,12005,12006,12007,
12008,12009,12010,12011,12012,12013,12014,12015,12016,12017,12018,12019,
12020,12021,12022,12023,12024,12025,12026,12027,12028,12029,12030,12031,
12032,12033,12034,12035,12036,12037,12038,12039,12040,12041,12042,12043,
12044,12045,12046,12047,12048,12049,12050,12051,12052,12053,12054,12055,
12056,12057,12058,12059,12060,12061,12062,12063,12064,12065,12066,12067,
12068,12069,12070,12071,12072,12073,12074,12075,12076,12077,12078,12079,
12080,12081,12082,12083,12084,12085,12086,12087,12088,12089,12090,12091,
12092,12093,12094,12095,12096,12097,12098,12099,12100,12101,12102,12103,
12104,12105,12106,12107,12108,12109,12110,12111,12112,12113,12114,12115,
12116,12117,12118,12119,12120,12121,12122,12123,12124,12125,12126,12127,
12128,12129,12130,12131,12132,12133,12134,12135,12136,12137,12138,12139,
12140,12141,12142,12143,12144,12145,12146,12147,12148,12149,12150,12151,
12152,12153,12154,12155,12156,12157,12158,12159,12160,12161,12162,12163,
12164,12165,12166,12167,12168,12169,12170,12171,12172,12173,12174,12175,
12176,12177,12178,12179,12180,12181,12182,12183,12184,12185,12186,12187,
12188,12189,12190,12191,12192,12193,12194,12195,12196,12197,12198,12199,
12200,12201,12202,12203,12204,12205,12206,12207,12208,12209,12210,12211,
12212,12213,12214,12215,12216,12217,12218,12219,12220,12221,12222,12223,
12224,12225,12226,12227,12228,12229,12230,12231,12232,12233,12234,12235,
12236,12237,12238,12239,12240,12241,12242,12243,12244,12245,12246,12247,
12248,12249,12250,12251,12252,12253,12254,12255,12256,12257,12258,12259,
12260,12261,12262,12263,12264,12265,12266,12267,12268,12269,12270,12271,
12272,12273,12274,12275,12276,12277,12278,12279,12280,12281,12282,12283,
12284,12285,12286,12287,12288,12289,12290,12291,12292,12293,12294,12295,
12296,12297,12298,12299,12300,12301,12302,12303,12304,12305,12306,12307,
12308,12309,12310,12311,12312,12313,12314,12315,12316,12317,12318,12319,
12320,12321,12322,12323,12324,12325,12326,12327,12328,12329,12330,12331,
12332,12333,12334,12335,12336,12337,12338,12339,12340,12341,12342,12343,
12344,12345,12346,12347,12348,12349,12350,12351,12352,12353,12354,12355,
12356,12357,12358,12359,12360,12361,12362,12363,12364,12365,12366,12367,
12368,12369,12370,12371,12372,12373,12374,12375,12376,12377,12378,12379,
12380,12381,12382,12383,12384,12385,12386,12387,12388,12389,12390,12391,
12392,12393,12394,12395,12396,12397,12398,12399,12400,12401,12402,12403,
12404,12405,12406,12407,12408,12409,12410,12411,12412,12413,12414,12415,
12416,12417,12418,12419,12420,12421,12422,12423,12424,12425,12426,12427,
12428,12429,12430,12431,12432,12433,12434,12435,12436,12437,12438,12439,
12440,12441,12442,12443,12444,12445,12446,12447,12448,12449,12450,12451,
12452,12453,12454,12455,12456,12457,12458,12459,12460,12461,12462,12463,
12464,12465,12466,12467,12468,12469,12470,12471,12472,12473,12474,12475,
12476,12477,12478,12479,12480,12481,12482,12483,12484,12485,12486,12487,
12488,12489,12490,12491,12492,12493,12494,12495,12496,12497,12498,12499,
12500,12501,12502,12503,12504,12505,12506,12507,12508,12509,12510,12511,
12512,12513,12514,12515,12516,12517,12518,12519,12520,12521,12522,12523,
12524,12525,12526,12527,12528,12529,12530,12531,12532,12533,12534,12535,
12536,12537,12538,12539,12540,12541,12542,12543,12544,12545,12546,12547,
12548,12549,12550,12551,12552,12553,12554,12555,12556,12557,12558,12559,
12560,12561,12562,12563,12564,12565,12566,12567,12568,12569,12570,12571,
12572,12573,12574,12575,12576,12577,12578,12579,12580,12581,12582,12583,
12584,12585,12586,12587,12588,12589,12590,12591,12592,12593,12594,12595,
12596,12597,12598,12599,12600,12601,12602,12603,12604,12605,12606,12607,
12608,12609,12610,12611,12612,12613,12614,12615,12616,12617,12618,12619,
12620,12621,12622,12623,12624,12625,12626,12627,12628,12629,12630,12631,
12632,12633,12634,12635,12636,12637,12638,12639,12640,12641,12642,12643,
12644,12645,12646,12647,12648,12649,12650,12651,12652,12653,12654,12655,
12656,12657,12658,12659,12660,12661,12662,12663,12664,12665,12666,12667,
12668,12669,12670,12671,12672,12673,12674,12675,12676,12677,12678,12679,
12680,12681,12682,12683,12684,12685,12686,12687,12688,12689,12690,12691,
12692,12693,12694,12695,12696,12697,12698,12699,12700,12701,12702,12703,
12704,12705,12706,12707,12708,12709,12710,12711,12712,12713,12714,12715,
12716,12717,12718,12719,12720,12721,12722,12723,12724,12725,12726,12727,
12728,12729,12730,12731,12732,12733,12734,12735,12736,12737,12738,12739,
12740,12741,12742,12743,12744,12745,12746,12747,12748,12749,12750,12751,
12752,12753,12754,12755,12756,12757,12758,12759,12760,12761,12762,12763,
12764,12765,12766,12767,12768,12769,12770,12771,12772,12773,12774,12775,
12776,12777,12778,12779,12780,12781,12782,12783,12784,12785,12786,12787,
12788,12789,12790,12791,12792,12793,12794,12795,12796,12797,12798,12799,
12800,12801,12802,12803,12804,12805,12806,12807,12808,12809,12810,12811,
12812,12813,12814,12815,12816,12817,12818,12819,12820,12821,12822,12823,
12824,12825,12826,12827,12828,12829,12830,12831,12832,12833,12834,12835,
12836,12837,12838,12839,12840,12841,12842,12843,12844,12845,12846,12847,
12848,12849,12850,12851,12852,12853,12854,12855,12856,12857,12858,12859,
12860,12861,12862,12863,12864,12865,12866,12867,12868,12869,12870,12871,
12872,12873,12874,12875,12876,12877,12878,12879,12880,12881,12882,12883,
12884,12885,12886,12887,12888,12889,12890,12891,12892,12893,12894,12895,
12896,12897,12898,12899,12900,12901,12902,12903,12904,12905,12906,12907,
12908,12909,12910,12911,12912,12913,12914,12915,12916,12917,12918,12919,
12920,12921,12922,12923,12924,12925,12926,12927,12928,12929,12930,12931,
12932,12933,12934,12935,12936,12937,12938,12939,12940,12941,12942,12943,
12944,12945,12946,12947,12948,12949,12950,12951,12952,12953,12954,12955,
12956,12957,12958,12959,12960,12961,12962,12963,12964,12965,12966,12967,
12968,12969,12970,12971,12972,12973,12974,12975,12976,12977,12978,12979,
12980,12981,12982,12983,12984,12985,12986,12987,12988,12989,12990,12991,
12992,12993,12994,12995,12996,12997,12998,12999,13000,13001,13002,13003,
13004,13005,13006,13007,13008,13009,13010,13011,13012,13013,13014,13015,
13016,13017,13018,13019,13020,13021,13022,13023,13024,13025,13026,13027,
13028,13029,13030,13031,13032,13033,13034,13035,13036,13037,13038,13039,
13040,13041,13042,13043,13044,13045,13046,13047,13048,13049,13050,13051,
13052,13053,13054,13055,13056,13057,13058,13059,13060,13061,13062,13063,
13064,13065,13066,13067,13068,13069,13070,13071,13072,13073,13074,13075,
13076,13077,13078,13079,13080,13081,13082,13083,13084,13085,13086,13087,
13088,13089,13090,13091,13092,13093,13094,13095,13096,13097,13098,13099,
13100,13101,13102,13103,13104,13105,13106,13107,13108,13109,13110,13111,
13112,13113,13114,13115,13116,13117,13118,13119,13120,13121,13122,13123,
13124,13125,13126,13127,13128,13129,13130,13131,13132,13133,13134,13135,
13136,13137,13138,13139,13140,13141,13142,13143,13144,13145,13146,13147,
13148,13149,13150,13151,13152,13153,13154,13155,13156,13157,13158,13159,
13160,13161,13162,13163,13164,13165,13166,13167,13168,13169,13170,13171,
13172,13173,13174,13175,13176,13177,13178,13179,13180,13181,13182,13183,
13184,13185,13186,13187,13188,13189,13190,13191,13192,13193,13194,13195,
13196,13197,13198,13199,13200,13201,13202,13203,13204,13205,13206,13207,
13208,13209,13210,13211,13212,13213,13214,13215,13216,13217,13218,13219,
13220,13221,13222,13223,13224,13225,13226,13227,13228,13229,13230,13231,
13232,13233,13234,13235,13236,13237,13238,13239,13240,13241,13242,13243,
13244,13245,13246,13247,13248,13249,13250,13251,13252,13253,13254,13255,
13256,13257,13258,13259,13260,13261,13262,13263,13264,13265,13266,13267,
13268,13269,13270,13271,13272,13273,13274,13275,13276,13277,13278,13279,
13280,13281,13282,13283,13284,13285,13286,13287,13288,13289,13290,13291,
13292,13293,13294,13295,13296,13297,13298,13299,13300,13301,13302,13303,
13304,13305,13306,13307,13308,13309,13310,13311,13312,13313,13314,13315,
13316,13317,13318,13319,13320,13321,13322,13323,13324,13325,13326,13327,
13328,13329,13330,13331,13332,13333,13334,13335,13336,13337,13338,13339,
13340,13341,13342,13343,13344,13345,13346,13347,13348,13349,13350,13351,
13352,13353,13354,13355,13356,13357,13358,13359,13360,13361,13362,13363,
13364,13365,13366,13367,13368,13369,13370,13371,13372,13373,13374,13375,
13376,13377,13378,13379,13380,13381,13382,13383,13384,13385,13386,13387,
13388,13389,13390,13391,13392,13393,13394,13395,13396,13397,13398,13399,
13400,13401,13402,13403,13404,13405,13406,13407,13408,13409,13410,13411,
13412,13413,13414,13415,13416,13417,13418,13419,13420,13421,13422,13423,
13424,13425,13426,13427,13428,13429,13430,13431,13432,13433,13434,13435,
13436,13437,13438,13439,13440,13441,13442,13443,13444,13445,13446,13447,
13448,13449,13450,13451,13452,13453,13454,13455,13456,13457,13458,13459,
13460,13461,13462,13463,13464,13465,13466,13467,13468,13469,13470,13471,
13472,13473,13474,13475,13476,13477,13478,13479,13480,13481,13482,13483,
13484,13485,13486,13487,13488,13489,13490,13491,13492,13493,13494,13495,
13496,13497,13498,13499,13500,13501,13502,13503,13504,13505,13506,13507,
13508,13509,13510,13511,13512,13513,13514,13515,13516,13517,13518,13519,
13520,13521,13522,13523,13524,13525,13526,13527,13528,13529,13530,13531,
13532,13533,13534,13535,13536,13537,13538,13539,13540,13541,13542,13543,
13544,13545,13546,13547,13548,13549,13550,13551,13552,13553,13554,13555,
13556,13557,13558,13559,13560,13561,13562,13563,13564,13565,13566,13567,
13568,13569,13570,13571,13572,13573,13574,13575,13576,13577,13578,13579,
13580,13581,13582,13583,13584,13585,13586,13587,13588,13589,13590,13591,
13592,13593,13594,13595,13596,13597,13598,13599,13600,13601,13602,13603,
13604,13605,13606,13607,13608,13609,13610,13611,13612,13613,13614,13615,
13616,13617,13618,13619,13620,13621,13622,13623,13624,13625,13626,13627,
13628,13629,13630,13631,13632,13633,13634,13635,13636,13637,13638,13639,
13640,13641,13642,13643,13644,13645,13646,13647,13648,13649,13650,13651,
13652,13653,13654,13655,13656,13657,13658,13659,13660,13661,13662,13663,
13664,13665,13666,13667,13668,13669,13670,13671,13672,13673,13674,13675,
13676,13677,13678,13679,13680,13681,13682,13683,13684,13685,13686,13687,
13688,13689,13690,13691,13692,13693,13694,13695,13696,13697,13698,13699,
13700,13701,13702,13703,13704,13705,13706,13707,13708,13709,13710,13711,
13712,13713,13714,13715,13716,13717,13718,13719,13720,13721,13722,13723,
13724,13725,13726,13727,13728,13729,13730,13731,13732,13733,13734,13735,
13736,13737,13738,13739,13740,13741,13742,13743,13744,13745,13746,13747,
13748,13749,13750,13751,13752,13753,13754,13755,13756,13757,13758,13759,
13760,13761,13762,13763,13764,13765,13766,13767,13768,13769,13770,13771,
13772,13773,13774,13775,13776,13777,13778,13779,13780,13781,13782,13783,
13784,13785,13786,13787,13788,13789,13790,13791,13792,13793,13794,13795,
13796,13797,13798,13799,13800,13801,13802,13803,13804,13805,13806,13807,
13808,13809,13810,13811,13812,13813,13814,13815,13816,13817,13818,13819,
13820,13821,13822,13823,13824,13825,13826,13827,13828,13829,13830,13831,
13832,13833,13834,13835,13836,13837,13838,13839,13840,13841,13842,13843,
13844,13845,13846,13847,13848,13849,13850,13851,13852,13853,13854,13855,
13856,13857,13858,13859,13860,13861,13862,13863,13864,13865,13866,13867,
13868,13869,13870,13871,13872,13873,13874,13875,13876,13877,13878,13879,
13880,13881,13882,13883,13884,13885,13886,13887,13888,13889,13890,13891,
13892,13893,13894,13895,13896,13897,13898,13899,13900,13901,13902,13903,
13904,13905,13906,13907,13908,13909,13910,13911,13912,13913,13914,13915,
13916,13917,13918,13919,13920,13921,13922,13923,13924,13925,13926,13927,
13928,13929,13930,13931,13932,13933,13934,13935,13936,13937,13938,13939,
13940,13941,13942,13943,13944,13945,13946,13947,13948,13949,13950,13951,
13952,13953,13954,13955,13956,13957,13958,13959,13960,13961,13962,13963,
13964,13965,13966,13967,13968,13969,13970,13971,13972,13973,13974,13975,
13976,13977,13978,13979,13980,13981,13982,13983,13984,13985,13986,13987,
13988,13989,13990,13991,13992,13993,13994,13995,13996,13997,13998,13999,
14000,14001,14002,14003,14004,14005,14006,14007,14008,14009,14010,14011,
14012,14013,14014,14015,14016,14017,14018,14019,14020,14021,14022,14023,
14024,14025,14026,14027,14028,14029,14030,14031,14032,14033,14034,14035,
14036,14037,14038,14039,14040,14041,14042,14043,14044,14045,14046,14047,
14048,14049,14050,14051,14052,14053,14054,14055,14056,14057,14058,14059,
14060,14061,14062,14063,14064,14065,14066,14067,14068,14069,14070,14071,
14072,14073,14074,14075,14076,14077,14078,14079,14080,14081,14082,14083,
14084,14085,14086,14087,14088,14089,14090,14091,14092,14093,14094,14095,
14096,14097,14098,14099,14100,14101,14102,14103,14104,14105,14106,14107,
14108,14109,14110,14111,14112,14113,14114,14115,14116,14117,14118,14119,
14120,14121,14122,14123,14124,14125,14126,14127,14128,14129,14130,14131,
14132,14133,14134,14135,14136,14137,14138,14139,14140,14141,14142,14143,
14144,14145,14146,14147,14148,14149,14150,14151,14152,14153,14154,14155,
14156,14157,14158,14159,14160,14161,14162,14163,14164,14165,14166,14167,
14168,14169,14170,14171,14172,14173,14174,14175,14176,14177,14178,14179,
14180,14181,14182,14183,14184,14185,14186,14187,14188,14189,14190,14191,
14192,14193,14194,14195,14196,14197,14198,14199,14200,14201,14202,14203,
14204,14205,14206,14207,14208,14209,14210,14211,14212,14213,14214,14215,
14216,14217,14218,14219,14220,14221,14222,14223,14224,14225,14226,14227,
14228,14229,14230,14231,14232,14233,14234,14235,14236,14237,14238,14239,
14240,14241,14242,14243,14244,14245,14246,14247,14248,14249,14250,14251,
14252,14253,14254,14255,14256,14257,14258,14259,14260,14261,14262,14263,
14264,14265,14266,14267,14268,14269,14270,14271,14272,14273,14274,14275,
14276,14277,14278,14279,14280,14281,14282,14283,14284,14285,14286,14287,
14288,14289,14290,14291,14292,14293,14294,14295,14296,14297,14298,14299,
14300,14301,14302,14303,14304,14305,14306,14307,14308,14309,14310,14311,
14312,14313,14314,14315,14316,14317,14318,14319,14320,14321,14322,14323,
14324,14325,14326,14327,14328,14329,14330,14331,14332,14333,14334,14335,
14336,14337,14338,14339,14340,14341,14342,14343,14344,14345,14346,14347,
14348,14349,14350,14351,14352,14353,14354,14355,14356,14357,14358,14359,
14360,14361,14362,14363,14364,14365,14366,14367,14368,14369,14370,14371,
14372,14373,14374,14375,14376,14377,14378,14379,14380,14381,14382,14383,
14384,14385,14386,14387,14388,14389,14390,14391,14392,14393,14394,14395,
14396,14397,14398,14399,14400,14401,14402,14403,14404,14405,14406,14407,
14408,14409,14410,14411,14412,14413,14414,14415,14416,14417,14418,14419,
14420,14421,14422,14423,14424,14425,14426,14427,14428,14429,14430,14431,
14432,14433,14434,14435,14436,14437,14438,14439,14440,14441,14442,14443,
14444,14445,14446,14447,14448,14449,14450,14451,14452,14453,14454,14455,
14456,14457,14458,14459,14460,14461,14462,14463,14464,14465,14466,14467,
14468,14469,14470,14471,14472,14473,14474,14475,14476,14477,14478,14479,
14480,14481,14482,14483,14484,14485,14486,14487,14488,14489,14490,14491,
14492,14493,14494,14495,14496,14497,14498,14499,14500,14501,14502,14503,
14504,14505,14506,14507,14508,14509,14510,14511,14512,14513,14514,14515,
14516,14517,14518,14519,14520,14521,14522,14523,14524,14525,14526,14527,
14528,14529,14530,14531,14532,14533,14534,14535,14536,14537,14538,14539,
14540,14541,14542,14543,14544,14545,14546,14547,14548,14549,14550,14551,
14552,14553,14554,14555,14556,14557,14558,14559,14560,14561,14562,14563,
14564,14565,14566,14567,14568,14569,14570,14571,14572,14573,14574,14575,
14576,14577,14578,14579,14580,14581,14582,14583,14584,14585,14586,14587,
14588,14589,14590,14591,14592,14593,14594,14595,14596,14597,14598,14599,
14600,14601,14602,14603,14604,14605,14606,14607,14608,14609,14610,14611,
14612,14613,14614,14615,14616,14617,14618,14619,14620,14621,14622,14623,
14624,14625,14626,14627,14628,14629,14630,14631,14632,14633,14634,14635,
14636,14637,14638,14639,14640,14641,14642,14643,14644,14645,14646,14647,
14648,14649,14650,14651,14652,14653,14654,14655,14656,14657,14658,14659,
14660,14661,14662,14663,14664,14665,14666,14667,14668,14669,14670,14671,
14672,14673,14674,14675,14676,14677,14678,14679,14680,14681,14682,14683,
14684,14685,14686,14687,14688,14689,14690,14691,14692,14693,14694,14695,
14696,14697,14698,14699,14700,14701,14702,14703,14704,14705,14706,14707,
14708,14709,14710,14711,14712,14713,14714,14715,14716,14717,14718,14719,
14720,14721,14722,14723,14724,14725,14726,14727,14728,14729,14730,14731,
14732,14733,14734,14735,14736,14737,14738,14739,14740,14741,14742,14743,
14744,14745,14746,14747,14748,14749,14750,14751,14752,14753,14754,14755,
14756,14757,14758,14759,14760,14761,14762,14763,14764,14765,14766,14767,
14768,14769,14770,14771,14772,14773,14774,14775,14776,14777,14778,14779,
14780,14781,14782,14783,14784,14785,14786,14787,14788,14789,14790,14791,
14792,14793,14794,14795,14796,14797,14798,14799,14800,14801,14802,14803,
14804,14805,14806,14807,14808,14809,14810,14811,14812,14813,14814,14815,
14816,14817,14818,14819,14820,14821,14822,14823,14824,14825,14826,14827,
14828,14829,14830,14831,14832,14833,14834,14835,14836,14837,14838,14839,
14840,14841,14842,14843,14844,14845,14846,14847,14848,14849,14850,14851,
14852,14853,14854,14855,14856,14857,14858,14859,14860,14861,14862,14863,
14864,14865,14866,14867,14868,14869,14870,14871,14872,14873,14874,14875,
14876,14877,14878,14879,14880,14881,14882,14883,14884,14885,14886,14887,
14888,14889,14890,14891,14892,14893,14894,14895,14896,14897,14898,14899,
14900,14901,14902,14903,14904,14905,14906,14907,14908,14909,14910,14911,
14912,14913,14914,14915,14916,14917,14918,14919,14920,14921,14922,14923,
14924,14925,14926,14927,14928,14929,14930,14931,14932,14933,14934,14935,
14936,14937,14938,14939,14940,14941,14942,14943,14944,14945,14946,14947,
14948,14949,14950,14951,14952,14953,14954,14955,14956,14957,14958,14959,
14960,14961,14962,14963,14964,14965,14966,14967,14968,14969,14970,14971,
14972,14973,14974,14975,14976,14977,14978,14979,14980,14981,14982,14983,
14984,14985,14986,14987,14988,14989,14990,14991,14992,14993,14994,14995,
14996,14997,14998,14999,15000,15001,15002,15003,15004,15005,15006,15007,
15008,15009,15010,15011,15012,15013,15014,15015,15016,15017,15018,15019,
15020,15021,15022,15023,15024,15025,15026,15027,15028,15029,15030,15031,
15032,15033,15034,15035,15036,15037,15038,15039,15040,15041,15042,15043,
15044,15045,15046,15047,15048,15049,15050,15051,15052,15053,15054,15055,
15056,15057,15058,15059,15060,15061,15062,15063,15064,15065,15066,15067,
15068,15069,15070,15071,15072,15073,15074,15075,15076,15077,15078,15079,
15080,15081,15082,15083,15084,15085,15086,15087,15088,15089,15090,15091,
15092,15093,15094,15095,15096,15097,15098,15099,15100,15101,15102,15103,
15104,15105,15106,15107,15108,15109,15110,15111,15112,15113,15114,15115,
15116,15117,15118,15119,15120,15121,15122,15123,15124,15125,15126,15127,
15128,15129,15130,15131,15132,15133,15134,15135,15136,15137,15138,15139,
15140,15141,15142,15143,15144,15145,15146,15147,15148,15149,15150,15151,
15152,15153,15154,15155,15156,15157,15158,15159,15160,15161,15162,15163,
15164,15165,15166,15167,15168,15169,15170,15171,15172,15173,15174,15175,
15176,15177,15178,15179,15180,15181,15182,15183,15184,15185,15186,15187,
15188,15189,15190,15191,15192,15193,15194,15195,15196,15197,15198,15199,
15200,15201,15202,15203,15204,15205,15206,15207,15208,15209,15210,15211,
15212,15213,15214,15215,15216,15217,15218,15219,15220,15221,15222,15223,
15224,15225,15226,15227,15228,15229,15230,15231,15232,15233,15234,15235,
15236,15237,15238,15239,15240,15241,15242,15243,15244,15245,15246,15247,
15248,15249,15250,15251,15252,15253,15254,15255,15256,15257,15258,15259,
15260,15261,15262,15263,15264,15265,15266,15267,15268,15269,15270,15271,
15272,15273,15274,15275,15276,15277,15278,15279,15280,15281,15282,15283,
15284,15285,15286,15287,15288,15289,15290,15291,15292,15293,15294,15295,
15296,15297,15298,15299,15300,15301,15302,15303,15304,15305,15306,15307,
15308,15309,15310,15311,15312,15313,15314,15315,15316,15317,15318,15319,
15320,15321,15322,15323,15324,15325,15326,15327,15328,15329,15330,15331,
15332,15333,15334,15335,15336,15337,15338,15339,15340,15341,15342,15343,
15344,15345,15346,15347,15348,15349,15350,15351,15352,15353,15354,15355,
15356,15357,15358,15359,15360,15361,15362,15363,15364,15365,15366,15367,
15368,15369,15370,15371,15372,15373,15374,15375,15376,15377,15378,15379,
15380,15381,15382,15383,15384,15385,15386,15387,15388,15389,15390,15391,
15392,15393,15394,15395,15396,15397,15398,15399,15400,15401,15402,15403,
15404,15405,15406,15407,15408,15409,15410,15411,15412,15413,15414,15415,
15416,15417,15418,15419,15420,15421,15422,15423,15424,15425,15426,15427,
15428,15429,15430,15431,15432,15433,15434,15435,15436,15437,15438,15439,
15440,15441,15442,15443,15444,15445,15446,15447,15448,15449,15450,15451,
15452,15453,15454,15455,15456,15457,15458,15459,15460,15461,15462,15463,
15464,15465,15466,15467,15468,15469,15470,15471,15472,15473,15474,15475,
15476,15477,15478,15479,15480,15481,15482,15483,15484,15485,15486,15487,
15488,15489,15490,15491,15492,15493,15494,15495,15496,15497,15498,15499,
15500,15501,15502,15503,15504,15505,15506,15507,15508,15509,15510,15511,
15512,15513,15514,15515,15516,15517,15518,15519,15520,15521,15522,15523,
15524,15525,15526,15527,15528,15529,15530,15531,15532,15533,15534,15535,
15536,15537,15538,15539,15540,15541,15542,15543,15544,15545,15546,15547,
15548,15549,15550,15551,15552,15553,15554,15555,15556,15557,15558,15559,
15560,15561,15562,15563,15564,15565,15566,15567,15568,15569,15570,15571,
15572,15573,15574,15575,15576,15577,15578,15579,15580,15581,15582,15583,
15584,15585,15586,15587,15588,15589,15590,15591,15592,15593,15594,15595,
15596,15597,15598,15599,15600,15601,15602,15603,15604,15605,15606,15607,
15608,15609,15610,15611,15612,15613,15614,15615,15616,15617,15618,15619,
15620,15621,15622,15623,15624,15625,15626,15627,15628,15629,15630,15631,
15632,15633,15634,15635,15636,15637,15638,15639,15640,15641,15642,15643,
15644,15645,15646,15647,15648,15649,15650,15651,15652,15653,15654,15655,
15656,15657,15658,15659,15660,15661,15662,15663,15664,15665,15666,15667,
15668,15669,15670,15671,15672,15673,15674,15675,15676,15677,15678,15679,
15680,15681,15682,15683,15684,15685,15686,15687,15688,15689,15690,15691,
15692,15693,15694,15695,15696,15697,15698,15699,15700,15701,15702,15703,
15704,15705,15706,15707,15708,15709,15710,15711,15712,15713,15714,15715,
15716,15717,15718,15719,15720,15721,15722,15723,15724,15725,15726,15727,
15728,15729,15730,15731,15732,15733,15734,15735,15736,15737,15738,15739,
15740,15741,15742,15743,15744,15745,15746,15747,15748,15749,15750,15751,
15752,15753,15754,15755,15756,15757,15758,15759,15760,15761,15762,15763,
15764,15765,15766,15767,15768,15769,15770,15771,15772,15773,15774,15775,
15776,15777,15778,15779,15780,15781,15782,15783,15784,15785,15786,15787,
15788,15789,15790,15791,15792,15793,15794,15795,15796,15797,15798,15799,
15800,15801,15802,15803,15804,15805,15806,15807,15808,15809,15810,15811,
15812,15813,15814,15815,15816,15817,15818,15819,15820,15821,15822,15823,
15824,15825,15826,15827,15828,15829,15830,15831,15832,15833,15834,15835,
15836,15837,15838,15839,15840,15841,15842,15843,15844,15845,15846,15847,
15848,15849,15850,15851,15852,15853,15854,15855,15856,15857,15858,15859,
15860,15861,15862,15863,15864,15865,15866,15867,15868,15869,15870,15871,
15872,15873,15874,15875,15876,15877,15878,15879,15880,15881,15882,15883,
15884,15885,15886,15887,15888,15889,15890,15891,15892,15893,15894,15895,
15896,15897,15898,15899,15900,15901,15902,15903,15904,15905,15906,15907,
15908,15909,15910,15911,15912,15913,15914,15915,15916,15917,15918,15919,
15920,15921,15922,15923,15924,15925,15926,15927,15928,15929,15930,15931,
15932,15933,15934,15935,15936,15937,15938,15939,15940,15941,15942,15943,
15944,15945,15946,15947,15948,15949,15950,15951,15952,15953,15954,15955,
15956,15957,15958,15959,15960,15961,15962,15963,15964,15965,15966,15967,
15968,15969,15970,15971,15972,15973,15974,15975,15976,15977,15978,15979,
15980,15981,15982,15983,15984,15985,15986,15987,15988,15989,15990,15991,
15992,15993,15994,15995,15996,15997,15998,15999,16000,16001,16002,16003,
16004,16005,16006,16007,16008,16009,16010,16011,16012,16013,16014,16015,
16016,16017,16018,16019,16020,16021,16022,16023,16024,16025,16026,16027,
16028,16029,16030,16031,16032,16033,16034,16035,16036,16037,16038,16039,
16040,16041,16042,16043,16044,16045,16046,16047,16048,16049,16050,16051,
16052,16053,16054,16055,16056,16057,16058,16059,16060,16061,16062,16063,
16064,16065,16066,16067,16068,16069,16070,16071,16072,16073,16074,16075,
16076,16077,16078,16079,16080,16081,16082,16083,16084,16085,16086,16087,
16088,16089,16090,16091,16092,16093,16094,16095,16096,16097,16098,16099,
16100,16101,16102,16103,16104,16105,16106,16107,16108,16109,16110,16111,
16112,16113,16114,16115,16116,16117,16118,16119,16120,16121,16122,16123,
16124,16125,16126,16127,16128,16129,16130,16131,16132,16133,16134,16135,
16136,16137,16138,16139,16140,16141,16142,16143,16144,16145,16146,16147,
16148,16149,16150,16151,16152,16153,16154,16155,16156,16157,16158,16159,
16160,16161,16162,16163,16164,16165,16166,16167,16168,16169,16170,16171,
16172,16173,16174,16175,16176,16177,16178,16179,16180,16181,16182,16183,
16184,16185,16186,16187,16188,16189,16190,16191,16192,16193,16194,16195,
16196,16197,16198,16199,16200,16201,16202,16203,16204,16205,16206,16207,
16208,16209,16210,16211,16212,16213,16214,16215,16216,16217,16218,16219,
16220,16221,16222,16223,16224,16225,16226,16227,16228,16229,16230,16231,
16232,16233,16234,16235,16236,16237,16238,16239,16240,16241,16242,16243,
16244,16245,16246,16247,16248,16249,16250,16251,16252,16253,16254,16255,
16256,16257,16258,16259,16260,16261,16262,16263,16264,16265,16266,16267,
16268,16269,16270,16271,16272,16273,16274,16275,16276,16277,16278,16279,
16280,16281,16282,16283,16284,16285,16286,16287,16288,16289,16290,16291,
16292,16293,16294,16295,16296,16297,16298,16299,16300,16301,16302,16303,
16304,16305,16306,16307,16308,16309,16310,16311,16312,16313,16314,16315,
16316,16317,16318,16319,16320,16321,16322,16323,16324,16325,16326,16327,
16328,16329,16330,16331,16332,16333,16334,16335,16336,16337,16338,16339,
16340,16341,16342,16343,16344,16345,16346,16347,16348,16349,16350,16351,
16352,16353,16354,16355,16356,16357,16358,16359,16360,16361,16362,16363,
16364,16365,16366,16367,16368,16369,16370,16371,16372,16373,16374,16375,
16376,16377,16378,16379,16380,16381,16382,16383,16384,16385,16386,16387,
16388,16389,16390,16391,16392,16393,16394,16395,16396,16397,16398,16399,
16400,16401,16402,16403,16404,16405,16406,16407,16408,16409,16410,16411,
16412,16413,16414,16415,16416,16417,16418,16419,16420,16421,16422,16423,
16424,16425,16426,16427,16428,16429,16430,16431,16432,16433,16434,16435,
16436,16437,16438,16439,16440,16441,16442,16443,16444,16445,16446,16447,
16448,16449,16450,16451,16452,16453,16454,16455,16456,16457,16458,16459,
16460,16461,16462,16463,16464,16465,16466,16467,16468,16469,16470,16471,
16472,16473,16474,16475,16476,16477,16478,16479,16480,16481,16482,16483,
16484,16485,16486,16487,16488,16489,16490,16491,16492,16493,16494,16495,
16496,16497,16498,16499,16500,16501,16502,16503,16504,16505,16506,16507,
16508,16509,16510,16511,16512,16513,16514,16515,16516,16517,16518,16519,
16520,16521,16522,16523,16524,16525,16526,16527,16528,16529,16530,16531,
16532,16533,16534,16535,16536,16537,16538,16539,16540,16541,16542,16543,
16544,16545,16546,16547,16548,16549,16550,16551,16552,16553,16554,16555,
16556,16557,16558,16559,16560,16561,16562,16563,16564,16565,16566,16567,
16568,16569,16570,16571,16572,16573,16574,16575,16576,16577,16578,16579,
16580,16581,16582,16583,16584,16585,16586,16587,16588,16589,16590,16591,
16592,16593,16594,16595,16596,16597,16598,16599,16600,16601,16602,16603,
16604,16605,16606,16607,16608,16609,16610,16611,16612,16613,16614,16615,
16616,16617,16618,16619,16620,16621,16622,16623,16624,16625,16626,16627,
16628,16629,16630,16631,16632,16633,16634,16635,16636,16637,16638,16639,
16640,16641,16642,16643,16644,16645,16646,16647,16648,16649,16650,16651,
16652,16653,16654,16655,16656,16657,16658,16659,16660,16661,16662,16663,
16664,16665,16666,16667,16668,16669,16670,16671,16672,16673,16674,16675,
16676,16677,16678,16679,16680,16681,16682,16683,16684,16685,16686,16687,
16688,16689,16690,16691,16692,16693,16694,16695,16696,16697,16698,16699,
16700,16701,16702,16703,16704,16705,16706,16707,16708,16709,16710,16711,
16712,16713,16714,16715,16716,16717,16718,16719,16720,16721,16722,16723,
16724,16725,16726,16727,16728,16729,16730,16731,16732,16733,16734,16735,
16736,16737,16738,16739,16740,16741,16742,16743,16744,16745,16746,16747,
16748,16749,16750,16751,16752,16753,16754,16755,16756,16757,16758,16759,
16760,16761,16762,16763,16764,16765,16766,16767,16768,16769,16770,16771,
16772,16773,16774,16775,16776,16777,16778,16779,16780,16781,16782,16783,
16784,16785,16786,16787,16788,16789,16790,16791,16792,16793,16794,16795,
16796,16797,16798,16799,16800,16801,16802,16803,16804,16805,16806,16807,
16808,16809,16810,16811,16812,16813,16814,16815,16816,16817,16818,16819,
16820,16821,16822,16823,16824,16825,16826,16827,16828,16829,16830,16831,
16832,16833,16834,16835,16836,16837,16838,16839,16840,16841,16842,16843,
16844,16845,16846,16847,16848,16849,16850,16851,16852,16853,16854,16855,
16856,16857,16858,16859,16860,16861,16862,16863,16864,16865,16866,16867,
16868,16869,16870,16871,16872,16873,16874,16875,16876,16877,16878,16879,
16880,16881,16882,16883,16884,16885,16886,16887,16888,16889,16890,16891,
16892,16893,16894,16895,16896,16897,16898,16899,16900,16901,16902,16903,
16904,16905,16906,16907,16908,16909,16910,16911,16912,16913,16914,16915,
16916,16917,16918,16919,16920,16921,16922,16923,16924,16925,16926,16927,
16928,16929,16930,16931,16932,16933,16934,16935,16936,16937,16938,16939,
16940,16941,16942,16943,16944,16945,16946,16947,16948,16949,16950,16951,
16952,16953,16954,16955,16956,16957,16958,16959,16960,16961,16962,16963,
16964,16965,16966,16967,16968,16969,16970,16971,16972,16973,16974,16975,
16976,16977,16978,16979,16980,16981,16982,16983,16984,16985,16986,16987,
16988,16989,16990,16991,16992,16993,16994,16995,16996,16997,16998,16999,
17000,17001,17002,17003,17004,17005,17006,17007,17008,17009,17010,17011,
17012,17013,17014,17015,17016,17017,17018,17019,17020,17021,17022,17023,
17024,17025,17026,17027,17028,17029,17030,17031,17032,17033,17034,17035,
17036,17037,17038,17039,17040,17041,17042,17043,17044,17045,17046,17047,
17048,17049,17050,17051,17052,17053,17054,17055,17056,17057,17058,17059,
17060,17061,17062,17063,17064,17065,17066,17067,17068,17069,17070,17071,
17072,17073,17074,17075,17076,17077,17078,17079,17080,17081,17082,17083,
17084,17085,17086,17087,17088,17089,17090,17091,17092,17093,17094,17095,
17096,17097,17098,17099,17100,17101,17102,17103,17104,17105,17106,17107,
17108,17109,17110,17111,17112,17113,17114,17115,17116,17117,17118,17119,
17120,17121,17122,17123,17124,17125,17126,17127,17128,17129,17130,17131,
17132,17133,17134,17135,17136,17137,17138,17139,17140,17141,17142,17143,
17144,17145,17146,17147,17148,17149,17150,17151,17152,17153,17154,17155,
17156,17157,17158,17159,17160,17161,17162,17163,17164,17165,17166,17167,
17168,17169,17170,17171,17172,17173,17174,17175,17176,17177,17178,17179,
17180,17181,17182,17183,17184,17185,17186,17187,17188,17189,17190,17191,
17192,17193,17194,17195,17196,17197,17198,17199,17200,17201,17202,17203,
17204,17205,17206,17207,17208,17209,17210,17211,17212,17213,17214,17215,
17216,17217,17218,17219,17220,17221,17222,17223,17224,17225,17226,17227,
17228,17229,17230,17231,17232,17233,17234,17235,17236,17237,17238,17239,
17240,17241,17242,17243,17244,17245,17246,17247,17248,17249,17250,17251,
17252,17253,17254,17255,17256,17257,17258,17259,17260,17261,17262,17263,
17264,17265,17266,17267,17268,17269,17270,17271,17272,17273,17274,17275,
17276,17277,17278,17279,17280,17281,17282,17283,17284,17285,17286,17287,
17288,17289,17290,17291,17292,17293,17294,17295,17296,17297,17298,17299,
17300,17301,17302,17303,17304,17305,17306,17307,17308,17309,17310,17311,
17312,17313,17314,17315,17316,17317,17318,17319,17320,17321,17322,17323,
17324,17325,17326,17327,17328,17329,17330,17331,17332,17333,17334,17335,
17336,17337,17338,17339,17340,17341,17342,17343,17344,17345,17346,17347,
17348,17349,17350,17351,17352,17353,17354,17355,17356,17357,17358,17359,
17360,17361,17362,17363,17364,17365,17366,17367,17368,17369,17370,17371,
17372,17373,17374,17375,17376,17377,17378,17379,17380,17381,17382,17383,
17384,17385,17386,17387,17388,17389,17390,17391,17392,17393,17394,17395,
17396,17397,17398,17399,17400,17401,17402,17403,17404,17405,17406,17407,
17408,17409,17410,17411,17412,17413,17414,17415,17416,17417,17418,17419,
17420,17421,17422,17423,17424,17425,17426,17427,17428,17429,17430,17431,
17432,17433,17434,17435,17436,17437,17438,17439,17440,17441,17442,17443,
17444,17445,17446,17447,17448,17449,17450,17451,17452,17453,17454,17455,
17456,17457,17458,17459,17460,17461,17462,17463,17464,17465,17466,17467,
17468,17469,17470,17471,17472,17473,17474,17475,17476,17477,17478,17479,
17480,17481,17482,17483,17484,17485,17486,17487,17488,17489,17490,17491,
17492,17493,17494,17495,17496,17497,17498,17499,17500,17501,17502,17503,
17504,17505,17506,17507,17508,17509,17510,17511,17512,17513,17514,17515,
17516,17517,17518,17519,17520,17521,17522,17523,17524,17525,17526,17527,
17528,17529,17530,17531,17532,17533,17534,17535,17536,17537,17538,17539,
17540,17541,17542,17543,17544,17545,17546,17547,17548,17549,17550,17551,
17552,17553,17554,17555,17556,17557,17558,17559,17560,17561,17562,17563,
17564,17565,17566,17567,17568,17569,17570,17571,17572,17573,17574,17575,
17576,17577,17578,17579,17580,17581,17582,17583,17584,17585,17586,17587,
17588,17589,17590,17591,17592,17593,17594,17595,17596,17597,17598,17599,
17600,17601,17602,17603,17604,17605,17606,17607,17608,17609,17610,17611,
17612,17613,17614,17615,17616,17617,17618,17619,17620,17621,17622,17623,
17624,17625,17626,17627,17628,17629,17630,17631,17632,17633,17634,17635,
17636,17637,17638,17639,17640,17641,17642,17643,17644,17645,17646,17647,
17648,17649,17650,17651,17652,17653,17654,17655,17656,17657,17658,17659,
17660,17661,17662,17663,17664,17665,17666,17667,17668,17669,17670,17671,
17672,17673,17674,17675,17676,17677,17678,17679,17680,17681,17682,17683,
17684,17685,17686,17687,17688,17689,17690,17691,17692,17693,17694,17695,
17696,17697,17698,17699,17700,17701,17702,17703,17704,17705,17706,17707,
17708,17709,17710,17711,17712,17713,17714,17715,17716,17717,17718,17719,
17720,17721,17722,17723,17724,17725,17726,17727,17728,17729,17730,17731,
17732,17733,17734,17735,17736,17737,17738,17739,17740,17741,17742,17743,
17744,17745,17746,17747,17748,17749,17750,17751,17752,17753,17754,17755,
17756,17757,17758,17759,17760,17761,17762,17763,17764,17765,17766,17767,
17768,17769,17770,17771,17772,17773,17774,17775,17776,17777,17778,17779,
17780,17781,17782,17783,17784,17785,17786,17787,17788,17789,17790,17791,
17792,17793,17794,17795,17796,17797,17798,17799,17800,17801,17802,17803,
17804,17805,17806,17807,17808,17809,17810,17811,17812,17813,17814,17815,
17816,17817,17818,17819,17820,17821,17822,17823,17824,17825,17826,17827,
17828,17829,17830,17831,17832,17833,17834,17835,17836,17837,17838,17839,
17840,17841,17842,17843,17844,17845,17846,17847,17848,17849,17850,17851,
17852,17853,17854,17855,17856,17857,17858,17859,17860,17861,17862,17863,
17864,17865,17866,17867,17868,17869,17870,17871,17872,17873,17874,17875,
17876,17877,17878,17879,17880,17881,17882,17883,17884,17885,17886,17887,
17888,17889,17890,17891,17892,17893,17894,17895,17896,17897,17898,17899,
17900,17901,17902,17903,17904,17905,17906,17907,17908,17909,17910,17911,
17912,17913,17914,17915,17916,17917,17918,17919,17920,17921,17922,17923,
17924,17925,17926,17927,17928,17929,17930,17931,17932,17933,17934,17935,
17936,17937,17938,17939,17940,17941,17942,17943,17944,17945,17946,17947,
17948,17949,17950,17951,17952,17953,17954,17955,17956,17957,17958,17959,
17960,17961,17962,17963,17964,17965,17966,17967,17968,17969,17970,17971,
17972,17973,17974,17975,17976,17977,17978,17979,17980,17981,17982,17983,
17984,17985,17986,17987,17988,17989,17990,17991,17992,17993,17994,17995,
17996,17997,17998,17999,18000,18001,18002,18003,18004,18005,18006,18007,
18008,18009,18010,18011,18012,18013,18014,18015,18016,18017,18018,18019,
18020,18021,18022,18023,18024,18025,18026,18027,18028,18029,18030,18031,
18032,18033,18034,18035,18036,18037,18038,18039,18040,18041,18042,18043,
18044,18045,18046,18047,18048,18049,18050,18051,18052,18053,18054,18055,
18056,18057,18058,18059,18060,18061,18062,18063,18064,18065,18066,18067,
18068,18069,18070,18071,18072,18073,18074,18075,18076,18077,18078,18079,
18080,18081,18082,18083,18084,18085,18086,18087,18088,18089,18090,18091,
18092,18093,18094,18095,18096,18097,18098,18099,18100,18101,18102,18103,
18104,18105,18106,18107,18108,18109,18110,18111,18112,18113,18114,18115,
18116,18117,18118,18119,18120,18121,18122,18123,18124,18125,18126,18127,
18128,18129,18130,18131,18132,18133,18134,18135,18136,18137,18138,18139,
18140,18141,18142,18143,18144,18145,18146,18147,18148,18149,18150,18151,
18152,18153,18154,18155,18156,18157,18158,18159,18160,18161,18162,18163,
18164,18165,18166,18167,18168,18169,18170,18171,18172,18173,18174,18175,
18176,18177,18178,18179,18180,18181,18182,18183,18184,18185,18186,18187,
18188,18189,18190,18191,18192,18193,18194,18195,18196,18197,18198,18199,
18200,18201,18202,18203,18204,18205,18206,18207,18208,18209,18210,18211,
18212,18213,18214,18215,18216,18217,18218,18219,18220,18221,18222,18223,
18224,18225,18226,18227,18228,18229,18230,18231,18232,18233,18234,18235,
18236,18237,18238,18239,18240,18241,18242,18243,18244,18245,18246,18247,
18248,18249,18250,18251,18252,18253,18254,18255,18256,18257,18258,18259,
18260,18261,18262,18263,18264,18265,18266,18267,18268,18269,18270,18271,
18272,18273,18274,18275,18276,18277,18278,18279,18280,18281,18282,18283,
18284,18285,18286,18287,18288,18289,18290,18291,18292,18293,18294,18295,
18296,18297,18298,18299,18300,18301,18302,18303,18304,18305,18306,18307,
18308,18309,18310,18311,18312,18313,18314,18315,18316,18317,18318,18319,
18320,18321,18322,18323,18324,18325,18326,18327,18328,18329,18330,18331,
18332,18333,18334,18335,18336,18337,18338,18339,18340,18341,18342,18343,
18344,18345,18346,18347,18348,18349,18350,18351,18352,18353,18354,18355,
18356,18357,18358,18359,18360,18361,18362,18363,18364,18365,18366,18367,
18368,18369,18370,18371,18372,18373,18374,18375,18376,18377,18378,18379,
18380,18381,18382,18383,18384,18385,18386,18387,18388,18389,18390,18391,
18392,18393,18394,18395,18396,18397,18398,18399,18400,18401,18402,18403,
18404,18405,18406,18407,18408,18409,18410,18411,18412,18413,18414,18415,
18416,18417,18418,18419,18420,18421,18422,18423,18424,18425,18426,18427,
18428,18429,18430,18431,18432,18433,18434,18435,18436,18437,18438,18439,
18440,18441,18442,18443,18444,18445,18446,18447,18448,18449,18450,18451,
18452,18453,18454,18455,18456,18457,18458,18459,18460,18461,18462,18463,
18464,18465,18466,18467,18468,18469,18470,18471,18472,18473,18474,18475,
18476,18477,18478,18479,18480,18481,18482,18483,18484,18485,18486,18487,
18488,18489,18490,18491,18492,18493,18494,18495,18496,18497,18498,18499,
18500,18501,18502,18503,18504,18505,18506,18507,18508,18509,18510,18511,
18512,18513,18514,18515,18516,18517,18518,18519,18520,18521,18522,18523,
18524,18525,18526,18527,18528,18529,18530,18531,18532,18533,18534,18535,
18536,18537,18538,18539,18540,18541,18542,18543,18544,18545,18546,18547,
18548,18549,18550,18551,18552,18553,18554,18555,18556,18557,18558,18559,
18560,18561,18562,18563,18564,18565,18566,18567,18568,18569,18570,18571,
18572,18573,18574,18575,18576,18577,18578,18579,18580,18581,18582,18583,
18584,18585,18586,18587,18588,18589,18590,18591,18592,18593,18594,18595,
18596,18597,18598,18599,18600,18601,18602,18603,18604,18605,18606,18607,
18608,18609,18610,18611,18612,18613,18614,18615,18616,18617,18618,18619,
18620,18621,18622,18623,18624,18625,18626,18627,18628,18629,18630,18631,
18632,18633,18634,18635,18636,18637,18638,18639,18640,18641,18642,18643,
18644,18645,18646,18647,18648,18649,18650,18651,18652,18653,18654,18655,
18656,18657,18658,18659,18660,18661,18662,18663,18664,18665,18666,18667,
18668,18669,18670,18671,18672,18673,18674,18675,18676,18677,18678,18679,
18680,18681,18682,18683,18684,18685,18686,18687,18688,18689,18690,18691,
18692,18693,18694,18695,18696,18697,18698,18699,18700,18701,18702,18703,
18704,18705,18706,18707,18708,18709,18710,18711,18712,18713,18714,18715,
18716,18717,18718,18719,18720,18721,18722,18723,18724,18725,18726,18727,
18728,18729,18730,18731,18732,18733,18734,18735,18736,18737,18738,18739,
18740,18741,18742,18743,18744,18745,18746,18747,18748,18749,18750,18751,
18752,18753,18754,18755,18756,18757,18758,18759,18760,18761,18762,18763,
18764,18765,18766,18767,18768,18769,18770,18771,18772,18773,18774,18775,
18776,18777,18778,18779,18780,18781,18782,18783,18784,18785,18786,18787,
18788,18789,18790,18791,18792,18793,18794,18795,18796,18797,18798,18799,
18800,18801,18802,18803,18804,18805,18806,18807,18808,18809,18810,18811,
18812,18813,18814,18815,18816,18817,18818,18819,18820,18821,18822,18823,
18824,18825,18826,18827,18828,18829,18830,18831,18832,18833,18834,18835,
18836,18837,18838,18839,18840,18841,18842,18843,18844,18845,18846,18847,
18848,18849,18850,18851,18852,18853,18854,18855,18856,18857,18858,18859,
18860,18861,18862,18863,18864,18865,18866,18867,18868,18869,18870,18871,
18872,18873,18874,18875,18876,18877,18878,18879,18880,18881,18882,18883,
18884,18885,18886,18887,18888,18889,18890,18891,18892,18893,18894,18895,
18896,18897,18898,18899,18900,18901,18902,18903,18904,18905,18906,18907,
18908,18909,18910,18911,18912,18913,18914,18915,18916,18917,18918,18919,
18920,18921,18922,18923,18924,18925,18926,18927,18928,18929,18930,18931,
18932,18933,18934,18935,18936,18937,18938,18939,18940,18941,18942,18943,
18944,18945,18946,18947,18948,18949,18950,18951,18952,18953,18954,18955,
18956,18957,18958,18959,18960,18961,18962,18963,18964,18965,18966,18967,
18968,18969,18970,18971,18972,18973,18974,18975,18976,18977,18978,18979,
18980,18981,18982,18983,18984,18985,18986,18987,18988,18989,18990,18991,
18992,18993,18994,18995,18996,18997,18998,18999,19000,19001,19002,19003,
19004,19005,19006,19007,19008,19009,19010,19011,19012,19013,19014,19015,
19016,19017,19018,19019,19020,19021,19022,19023,19024,19025,19026,19027,
19028,19029,19030,19031,19032,19033,19034,19035,19036,19037,19038,19039,
19040,19041,19042,19043,19044,19045,19046,19047,19048,19049,19050,19051,
19052,19053,19054,19055,19056,19057,19058,19059,19060,19061,19062,19063,
19064,19065,19066,19067,19068,19069,19070,19071,19072,19073,19074,19075,
19076,19077,19078,19079,19080,19081,19082,19083,19084,19085,19086,19087,
19088,19089,19090,19091,19092,19093,19094,19095,19096,19097,19098,19099,
19100,19101,19102,19103,19104,19105,19106,19107,19108,19109,19110,19111,
19112,19113,19114,19115,19116,19117,19118,19119,19120,19121,19122,19123,
19124,19125,19126,19127,19128,19129,19130,19131,19132,19133,19134,19135,
19136,19137,19138,19139,19140,19141,19142,19143,19144,19145,19146,19147,
19148,19149,19150,19151,19152,19153,19154,19155,19156,19157,19158,19159,
19160,19161,19162,19163,19164,19165,19166,19167,19168,19169,19170,19171,
19172,19173,19174,19175,19176,19177,19178,19179,19180,19181,19182,19183,
19184,19185,19186,19187,19188,19189,19190,19191,19192,19193,19194,19195,
19196,19197,19198,19199,19200,19201,19202,19203,19204,19205,19206,19207,
19208,19209,19210,19211,19212,19213,19214,19215,19216,19217,19218,19219,
19220,19221,19222,19223,19224,19225,19226,19227,19228,19229,19230,19231,
19232,19233,19234,19235,19236,19237,19238,19239,19240,19241,19242,19243,
19244,19245,19246,19247,19248,19249,19250,19251,19252,19253,19254,19255,
19256,19257,19258,19259,19260,19261,19262,19263,19264,19265,19266,19267,
19268,19269,19270,19271,19272,19273,19274,19275,19276,19277,19278,19279,
19280,19281,19282,19283,19284,19285,19286,19287,19288,19289,19290,19291,
19292,19293,19294,19295,19296,19297,19298,19299,19300,19301,19302,19303,
19304,19305,19306,19307,19308,19309,19310,19311,19312,19313,19314,19315,
19316,19317,19318,19319,19320,19321,19322,19323,19324,19325,19326,19327,
19328,19329,19330,19331,19332,19333,19334,19335,19336,19337,19338,19339,
19340,19341,19342,19343,19344,19345,19346,19347,19348,19349,19350,19351,
19352,19353,19354,19355,19356,19357,19358,19359,19360,19361,19362,19363,
19364,19365,19366,19367,19368,19369,19370,19371,19372,19373,19374,19375,
19376,19377,19378,19379,19380,19381,19382,19383,19384,19385,19386,19387,
19388,19389,19390,19391,19392,19393,19394,19395,19396,19397,19398,19399,
19400,19401,19402,19403,19404,19405,19406,19407,19408,19409,19410,19411,
19412,19413,19414,19415,19416,19417,19418,19419,19420,19421,19422,19423,
19424,19425,19426,19427,19428,19429,19430,19431,19432,19433,19434,19435,
19436,19437,19438,19439,19440,19441,19442,19443,19444,19445,19446,19447,
19448,19449,19450,19451,19452,19453,19454,19455,19456,19457,19458,19459,
19460,19461,19462,19463,19464,19465,19466,19467,19468,19469,19470,19471,
19472,19473,19474,19475,19476,19477,19478,19479,19480,19481,19482,19483,
19484,19485,19486,19487,19488,19489,19490,19491,19492,19493,19494,19495,
19496,19497,19498,19499,19500,19501,19502,19503,19504,19505,19506,19507,
19508,19509,19510,19511,19512,19513,19514,19515,19516,19517,19518,19519,
19520,19521,19522,19523,19524,19525,19526,19527,19528,19529,19530,19531,
19532,19533,19534,19535,19536,19537,19538,19539,19540,19541,19542,19543,
19544,19545,19546,19547,19548,19549,19550,19551,19552,19553,19554,19555,
19556,19557,19558,19559,19560,19561,19562,19563,19564,19565,19566,19567,
19568,19569,19570,19571,19572,19573,19574,19575,19576,19577,19578,19579,
19580,19581,19582,19583,19584,19585,19586,19587,19588,19589,19590,19591,
19592,19593,19594,19595,19596,19597,19598,19599,19600,19601,19602,19603,
19604,19605,19606,19607,19608,19609,19610,19611,19612,19613,19614,19615,
19616,19617,19618,19619,19620,19621,19622,19623,19624,19625,19626,19627,
19628,19629,19630,19631,19632,19633,19634,19635,19636,19637,19638,19639,
19640,19641,19642,19643,19644,19645,19646,19647,19648,19649,19650,19651,
19652,19653,19654,19655,19656,19657,19658,19659,19660,19661,19662,19663,
19664,19665,19666,19667,19668,19669,19670,19671,19672,19673,19674,19675,
19676,19677,19678,19679,19680,19681,19682,19683,19684,19685,19686,19687,
19688,19689,19690,19691,19692,19693,19694,19695,19696,19697,19698,19699,
19700,19701,19702,19703,19704,19705,19706,19707,19708,19709,19710,19711,
19712,19713,19714,19715,19716,19717,19718,19719,19720,19721,19722,19723,
19724,19725,19726,19727,19728,19729,19730,19731,19732,19733,19734,19735,
19736,19737,19738,19739,19740,19741,19742,19743,19744,19745,19746,19747,
19748,19749,19750,19751,19752,19753,19754,19755,19756,19757,19758,19759,
19760,19761,19762,19763,19764,19765,19766,19767,19768,19769,19770,19771,
19772,19773,19774,19775,19776,19777,19778,19779,19780,19781,19782,19783,
19784,19785,19786,19787,19788,19789,19790,19791,19792,19793,19794,19795,
19796,19797,19798,19799,19800,19801,19802,19803,19804,19805,19806,19807,
19808,19809,19810,19811,19812,19813,19814,19815,19816,19817,19818,19819,
19820,19821,19822,19823,19824,19825,19826,19827,19828,19829,19830,19831,
19832,19833,19834,19835,19836,19837,19838,19839,19840,19841,19842,19843,
19844,19845,19846,19847,19848,19849,19850,19851,19852,19853,19854,19855,
19856,19857,19858,19859,19860,19861,19862,19863,19864,19865,19866,19867,
19868,19869,19870,19871,19872,19873,19874,19875,19876,19877,19878,19879,
19880,19881,19882,19883,19884,19885,19886,19887,19888,19889,19890,19891,
19892,19893,19894,19895,19896,19897,19898,19899,19900,19901,19902,19903,
19904,19905,19906,19907,19908,19909,19910,19911,19912,19913,19914,19915,
19916,19917,19918,19919,19920,19921,19922,19923,19924,19925,19926,19927,
19928,19929,19930,19931,19932,19933,19934,19935,19936,19937,19938,19939,
19940,19941,19942,19943,19944,19945,19946,19947,19948,19949,19950,19951,
19952,19953,19954,19955,19956,19957,19958,19959,19960,19961,19962,19963,
19964,19965,19966,19967,19968,19969,19970,19971,19972,19973,19974,19975,
19976,19977,19978,19979,19980,19981,19982,19983,19984,19985,19986,19987,
19988,19989,19990,19991,19992,19993,19994,19995,19996,19997,19998,19999,
20000,20001,20002,20003,20004,20005,20006,20007,20008,20009,20010,20011,
20012,20013,20014,20015,20016,20017,20018,20019,20020,20021,20022,20023,
20024,20025,20026,20027,20028,20029,20030,20031,20032,20033,20034,20035,
20036,20037,20038,20039,20040,20041,20042,20043,20044,20045,20046,20047,
20048,20049,20050,20051,20052,20053,20054,20055,20056,20057,20058,20059,
20060,20061,20062,20063,20064,20065,20066,20067,20068,20069,20070,20071,
20072,20073,20074,20075,20076,20077,20078,20079,20080,20081,20082,20083,
20084,20085,20086,20087,20088,20089,20090,20091,20092,20093,20094,20095,
20096,20097,20098,20099,20100,20101,20102,20103,20104,20105,20106,20107,
20108,20109,20110,20111,20112,20113,20114,20115,20116,20117,20118,20119,
20120,20121,20122,20123,20124,20125,20126,20127,20128,20129,20130,20131,
20132,20133,20134,20135,20136,20137,20138,20139,20140,20141,20142,20143,
20144,20145,20146,20147,20148,20149,20150,20151,20152,20153,20154,20155,
20156,20157,20158,20159,20160,20161,20162,20163,20164,20165,20166,20167,
20168,20169,20170,20171,20172,20173,20174,20175,20176,20177,20178,20179,
20180,20181,20182,20183,20184,20185,20186,20187,20188,20189,20190,20191,
20192,20193,20194,20195,20196,20197,20198,20199,20200,20201,20202,20203,
20204,20205,20206,20207,20208,20209,20210,20211,20212,20213,20214,20215,
20216,20217,20218,20219,20220,20221,20222,20223,20224,20225,20226,20227,
20228,20229,20230,20231,20232,20233,20234,20235,20236,20237,20238,20239,
20240,20241,20242,20243,20244,20245,20246,20247,20248,20249,20250,20251,
20252,20253,20254,20255,20256,20257,20258,20259,20260,20261,20262,20263,
20264,20265,20266,20267,20268,20269,20270,20271,20272,20273,20274,20275,
20276,20277,20278,20279,20280,20281,20282,20283,20284,20285,20286,20287,
20288,20289,20290,20291,20292,20293,20294,20295,20296,20297,20298,20299,
20300,20301,20302,20303,20304,20305,20306,20307,20308,20309,20310,20311,
20312,20313,20314,20315,20316,20317,20318,20319,20320,20321,20322,20323,
20324,20325,20326,20327,20328,20329,20330,20331,20332,20333,20334,20335,
20336,20337,20338,20339,20340,20341,20342,20343,20344,20345,20346,20347,
20348,20349,20350,20351,20352,20353,20354,20355,20356,20357,20358,20359,
20360,20361,20362,20363,20364,20365,20366,20367,20368,20369,20370,20371,
20372,20373,20374,20375,20376,20377,20378,20379,20380,20381,20382,20383,
20384,20385,20386,20387,20388,20389,20390,20391,20392,20393,20394,20395,
20396,20397,20398,20399,20400,20401,20402,20403,20404,20405,20406,20407,
20408,20409,20410,20411,20412,20413,20414,20415,20416,20417,20418,20419,
20420,20421,20422,20423,20424,20425,20426,20427,20428,20429,20430,20431,
20432,20433,20434,20435,20436,20437,20438,20439,20440,20441,20442,20443,
20444,20445,20446,20447,20448,20449,20450,20451,20452,20453,20454,20455,
20456,20457,20458,20459,20460,20461,20462,20463,20464,20465,20466,20467,
20468,20469,20470,20471,20472,20473,20474,20475,20476,20477,20478,20479,
20480,20481,20482,20483,20484,20485,20486,20487,20488,20489,20490,20491,
20492,20493,20494,20495,20496,20497,20498,20499,20500,20501,20502,20503,
20504,20505,20506,20507,20508,20509,20510,20511,20512,20513,20514,20515,
20516,20517,20518,20519,20520,20521,20522,20523,20524,20525,20526,20527,
20528,20529,20530,20531,20532,20533,20534,20535,20536,20537,20538,20539,
20540,20541,20542,20543,20544,20545,20546,20547,20548,20549,20550,20551,
20552,20553,20554,20555,20556,20557,20558,20559,20560,20561,20562,20563,
20564,20565,20566,20567,20568,20569,20570,20571,20572,20573,20574,20575,
20576,20577,20578,20579,20580,20581,20582,20583,20584,20585,20586,20587,
20588,20589,20590,20591,20592,20593,20594,20595,20596,20597,20598,20599,
20600,20601,20602,20603,20604,20605,20606,20607,20608,20609,20610,20611,
20612,20613,20614,20615,20616,20617,20618,20619,20620,20621,20622,20623,
20624,20625,20626,20627,20628,20629,20630,20631,20632,20633,20634,20635,
20636,20637,20638,20639,20640,20641,20642,20643,20644,20645,20646,20647,
20648,20649,20650,20651,20652,20653,20654,20655,20656,20657,20658,20659,
20660,20661,20662,20663,20664,20665,20666,20667,20668,20669,20670,20671,
20672,20673,20674,20675,20676,20677,20678,20679,20680,20681,20682,20683,
20684,20685,20686,20687,20688,20689,20690,20691,20692,20693,20694,20695,
20696,20697,20698,20699,20700,20701,20702,20703,20704,20705,20706,20707,
20708,20709,20710,20711,20712,20713,20714,20715,20716,20717,20718,20719,
20720,20721,20722,20723,20724,20725,20726,20727,20728,20729,20730,20731,
20732,20733,20734,20735,20736,20737,20738,20739,20740,20741,20742,20743,
20744,20745,20746,20747,20748,20749,20750,20751,20752,20753,20754,20755,
20756,20757,20758,20759,20760,20761,20762,20763,20764,20765,20766,20767,
20768,20769,20770,20771,20772,20773,20774,20775,20776,20777,20778,20779,
20780,20781,20782,20783,20784,20785,20786,20787,20788,20789,20790,20791,
20792,20793,20794,20795,20796,20797,20798,20799,20800,20801,20802,20803,
20804,20805,20806,20807,20808,20809,20810,20811,20812,20813,20814,20815,
20816,20817,20818,20819,20820,20821,20822,20823,20824,20825,20826,20827,
20828,20829,20830,20831,20832,20833,20834,20835,20836,20837,20838,20839,
20840,20841,20842,20843,20844,20845,20846,20847,20848,20849,20850,20851,
20852,20853,20854,20855,20856,20857,20858,20859,20860,20861,20862,20863,
20864,20865,20866,20867,20868,20869,20870,20871,20872,20873,20874,20875,
20876,20877,20878,20879,20880,20881,20882,20883,20884,20885,20886,20887,
20888,20889,20890,20891,20892,20893,20894,20895,20896,20897,20898,20899,
20900,20901,20902,20903,20904,20905,20906,20907,20908,20909,20910,20911,
20912,20913,20914,20915,20916,20917,20918,20919,20920,20921,20922,20923,
20924,20925,20926,20927,20928,20929,20930,20931,20932,20933,20934,20935,
20936,20937,20938,20939,20940,20941,20942,20943,20944,20945,20946,20947,
20948,20949,20950,20951,20952,20953,20954,20955,20956,20957,20958,20959,
20960,20961,20962,20963,20964,20965,20966,20967,20968,20969,20970,20971,
20972,20973,20974,20975,20976,20977,20978,20979,20980,20981,20982,20983,
20984,20985,20986,20987,20988,20989,20990,20991,20992,20993,20994,20995,
20996,20997,20998,20999,21000,21001,21002,21003,21004,21005,21006,21007,
21008,21009,21010,21011,21012,21013,21014,21015,21016,21017,21018,21019,
21020,21021,21022,21023,21024,21025,21026,21027,21028,21029,21030,21031,
21032,21033,21034,21035,21036,21037,21038,21039,21040,21041,21042,21043,
21044,21045,21046,21047,21048,21049,21050,21051,21052,21053,21054,21055,
21056,21057,21058,21059,21060,21061,21062,21063,21064,21065,21066,21067,
21068,21069,21070,21071,21072,21073,21074,21075,21076,21077,21078,21079,
21080,21081,21082,21083,21084,21085,21086,21087,21088,21089,21090,21091,
21092,21093,21094,21095,21096,21097,21098,21099,21100,21101,21102,21103,
21104,21105,21106,21107,21108,21109,21110,21111,21112,21113,21114,21115,
21116,21117,21118,21119,21120,21121,21122,21123,21124,21125,21126,21127,
21128,21129,21130,21131,21132,21133,21134,21135,21136,21137,21138,21139,
21140,21141,21142,21143,21144,21145,21146,21147,21148,21149,21150,21151,
21152,21153,21154,21155,21156,21157,21158,21159,21160,21161,21162,21163,
21164,21165,21166,21167,21168,21169,21170,21171,21172,21173,21174,21175,
21176,21177,21178,21179,21180,21181,21182,21183,21184,21185,21186,21187,
21188,21189,21190,21191,21192,21193,21194,21195,21196,21197,21198,21199,
21200,21201,21202,21203,21204,21205,21206,21207,21208,21209,21210,21211,
21212,21213,21214,21215,21216,21217,21218,21219,21220,21221,21222,21223,
21224,21225,21226,21227,21228,21229,21230,21231,21232,21233,21234,21235,
21236,21237,21238,21239,21240,21241,21242,21243,21244,21245,21246,21247,
21248,21249,21250,21251,21252,21253,21254,21255,21256,21257,21258,21259,
21260,21261,21262,21263,21264,21265,21266,21267,21268,21269,21270,21271,
21272,21273,21274,21275,21276,21277,21278,21279,21280,21281,21282,21283,
21284,21285,21286,21287,21288,21289,21290,21291,21292,21293,21294,21295,
21296,21297,21298,21299,21300,21301,21302,21303,21304,21305,21306,21307,
21308,21309,21310,21311,21312,21313,21314,21315,21316,21317,21318,21319,
21320,21321,21322,21323,21324,21325,21326,21327,21328,21329,21330,21331,
21332,21333,21334,21335,21336,21337,21338,21339,21340,21341,21342,21343,
21344,21345,21346,21347,21348,21349,21350,21351,21352,21353,21354,21355,
21356,21357,21358,21359,21360,21361,21362,21363,21364,21365,21366,21367,
21368,21369,21370,21371,21372,21373,21374,21375,21376,21377,21378,21379,
21380,21381,21382,21383,21384,21385,21386,21387,21388,21389,21390,21391,
21392,21393,21394,21395,21396,21397,21398,21399,21400,21401,21402,21403,
21404,21405,21406,21407,21408,21409,21410,21411,21412,21413,21414,21415,
21416,21417,21418,21419,21420,21421,21422,21423,21424,21425,21426,21427,
21428,21429,21430,21431,21432,21433,21434,21435,21436,21437,21438,21439,
21440,21441,21442,21443,21444,21445,21446,21447,21448,21449,21450,21451,
21452,21453,21454,21455,21456,21457,21458,21459,21460,21461,21462,21463,
21464,21465,21466,21467,21468,21469,21470,21471,21472,21473,21474,21475,
21476,21477,21478,21479,21480,21481,21482,21483,21484,21485,21486,21487,
21488,21489,21490,21491,21492,21493,21494,21495,21496,21497,21498,21499,
21500,21501,21502,21503,21504,21505,21506,21507,21508,21509,21510,21511,
21512,21513,21514,21515,21516,21517,21518,21519,21520,21521,21522,21523,
21524,21525,21526,21527,21528,21529,21530,21531,21532,21533,21534,21535,
21536,21537,21538,21539,21540,21541,21542,21543,21544,21545,21546,21547,
21548,21549,21550,21551,21552,21553,21554,21555,21556,21557,21558,21559,
21560,21561,21562,21563,21564,21565,21566,21567,21568,21569,21570,21571,
21572,21573,21574,21575,21576,21577,21578,21579,21580,21581,21582,21583,
21584,21585,21586,21587,21588,21589,21590,21591,21592,21593,21594,21595,
21596,21597,21598,21599,21600,21601,21602,21603,21604,21605,21606,21607,
21608,21609,21610,21611,21612,21613,21614,21615,21616,21617,21618,21619,
21620,21621,21622,21623,21624,21625,21626,21627,21628,21629,21630,21631,
21632,21633,21634,21635,21636,21637,21638,21639,21640,21641,21642,21643,
21644,21645,21646,21647,21648,21649,21650,21651,21652,21653,21654,21655,
21656,21657,21658,21659,21660,21661,21662,21663,21664,21665,21666,21667,
21668,21669,21670,21671,21672,21673,21674,21675,21676,21677,21678,21679,
21680,21681,21682,21683,21684,21685,21686,21687,21688,21689,21690,21691,
21692,21693,21694,21695,21696,21697,21698,21699,21700,21701,21702,21703,
21704,21705,21706,21707,21708,21709,21710,21711,21712,21713,21714,21715,
21716,21717,21718,21719,21720,21721,21722,21723,21724,21725,21726,21727,
21728,21729,21730,21731,21732,21733,21734,21735,21736,21737,21738,21739,
21740,21741,21742,21743,21744,21745,21746,21747,21748,21749,21750,21751,
21752,21753,21754,21755,21756,21757,21758,21759,21760,21761,21762,21763,
21764,21765,21766,21767,21768,21769,21770,21771,21772,21773,21774,21775,
21776,21777,21778,21779,21780,21781,21782,21783,21784,21785,21786,21787,
21788,21789,21790,21791,21792,21793,21794,21795,21796,21797,21798,21799,
21800,21801,21802,21803,21804,21805,21806,21807,21808,21809,21810,21811,
21812,21813,21814,21815,21816,21817,21818,21819,21820,21821,21822,21823,
21824,21825,21826,21827,21828,21829,21830,21831,21832,21833,21834,21835,
21836,21837,21838,21839,21840,21841,21842,21843,21844,21845,21846,21847,
21848,21849,21850,21851,21852,21853,21854,21855,21856,21857,21858,21859,
21860,21861,21862,21863,21864,21865,21866,21867,21868,21869,21870,21871,
21872,21873,21874,21875,21876,21877,21878,21879,21880,21881,21882,21883,
21884,21885,21886,21887,21888,21889,21890,21891,21892,21893,21894,21895,
21896,21897,21898,21899,21900,21901,21902,21903,21904,21905,21906,21907,
21908,21909,21910,21911,21912,21913,21914,21915,21916,21917,21918,21919,
21920,21921,21922,21923,21924,21925,21926,21927,21928,21929,21930,21931,
21932,21933,21934,21935,21936,21937,21938,21939,21940,21941,21942,21943,
21944,21945,21946,21947,21948,21949,21950,21951,21952,21953,21954,21955,
21956,21957,21958,21959,21960,21961,21962,21963,21964,21965,21966,21967,
21968,21969,21970,21971,21972,21973,21974,21975,21976,21977,21978,21979,
21980,21981,21982,21983,21984,21985,21986,21987,21988,21989,21990,21991,
21992,21993,21994,21995,21996,21997,21998,21999,22000,22001,22002,22003,
22004,22005,22006,22007,22008,22009,22010,22011,22012,22013,22014,22015,
22016,22017,22018,22019,22020,22021,22022,22023,22024,22025,22026,22027,
22028,22029,22030,22031,22032,22033,22034,22035,22036,22037,22038,22039,
22040,22041,22042,22043,22044,22045,22046,22047,22048,22049,22050,22051,
22052,22053,22054,22055,22056,22057,22058,22059,22060,22061,22062,22063,
22064,22065,22066,22067,22068,22069,22070,22071,22072,22073,22074,22075,
22076,22077,22078,22079,22080,22081,22082,22083,22084,22085,22086,22087,
22088,22089,22090,22091,22092,22093,22094,22095,22096,22097,22098,22099,
22100,22101,22102,22103,22104,22105,22106,22107,22108,22109,22110,22111,
22112,22113,22114,22115,22116,22117,22118,22119,22120,22121,22122,22123,
22124,22125,22126,22127,22128,22129,22130,22131,22132,22133,22134,22135,
22136,22137,22138,22139,22140,22141,22142,22143,22144,22145,22146,22147,
22148,22149,22150,22151,22152,22153,22154,22155,22156,22157,22158,22159,
22160,22161,22162,22163,22164,22165,22166,22167,22168,22169,22170,22171,
22172,22173,22174,22175,22176,22177,22178,22179,22180,22181,22182,22183,
22184,22185,22186,22187,22188,22189,22190,22191,22192,22193,22194,22195,
22196,22197,22198,22199,22200,22201,22202,22203,22204,22205,22206,22207,
22208,22209,22210,22211,22212,22213,22214,22215,22216,22217,22218,22219,
22220,22221,22222,22223,22224,22225,22226,22227,22228,22229,22230,22231,
22232,22233,22234,22235,22236,22237,22238,22239,22240,22241,22242,22243,
22244,22245,22246,22247,22248,22249,22250,22251,22252,22253,22254,22255,
22256,22257,22258,22259,22260,22261,22262,22263,22264,22265,22266,22267,
22268,22269,22270,22271,22272,22273,22274,22275,22276,22277,22278,22279,
22280,22281,22282,22283,22284,22285,22286,22287,22288,22289,22290,22291,
22292,22293,22294,22295,22296,22297,22298,22299,22300,22301,22302,22303,
22304,22305,22306,22307,22308,22309,22310,22311,22312,22313,22314,22315,
22316,22317,22318,22319,22320,22321,22322,22323,22324,22325,22326,22327,
22328,22329,22330,22331,22332,22333,22334,22335,22336,22337,22338,22339,
22340,22341,22342,22343,22344,22345,22346,22347,22348,22349,22350,22351,
22352,22353,22354,22355,22356,22357,22358,22359,22360,22361,22362,22363,
22364,22365,22366,22367,22368,22369,22370,22371,22372,22373,22374,22375,
22376,22377,22378,22379,22380,22381,22382,22383,22384,22385,22386,22387,
22388,22389,22390,22391,22392,22393,22394,22395,22396,22397,22398,22399,
22400,22401,22402,22403,22404,22405,22406,22407,22408,22409,22410,22411,
22412,22413,22414,22415,22416,22417,22418,22419,22420,22421,22422,22423,
22424,22425,22426,22427,22428,22429,22430,22431,22432,22433,22434,22435,
22436,22437,22438,22439,22440,22441,22442,22443,22444,22445,22446,22447,
22448,22449,22450,22451,22452,22453,22454,22455,22456,22457,22458,22459,
22460,22461,22462,22463,22464,22465,22466,22467,22468,22469,22470,22471,
22472,22473,22474,22475,22476,22477,22478,22479,22480,22481,22482,22483,
22484,22485,22486,22487,22488,22489,22490,22491,22492,22493,22494,22495,
22496,22497,22498,22499,22500,22501,22502,22503,22504,22505,22506,22507,
22508,22509,22510,22511,22512,22513,22514,22515,22516,22517,22518,22519,
22520,22521,22522,22523,22524,22525,22526,22527,22528,22529,22530,22531,
22532,22533,22534,22535,22536,22537,22538,22539,22540,22541,22542,22543,
22544,22545,22546,22547,22548,22549,22550,22551,22552,22553,22554,22555,
22556,22557,22558,22559,22560,22561,22562,22563,22564,22565,22566,22567,
22568,22569,22570,22571,22572,22573,22574,22575,22576,22577,22578,22579,
22580,22581,22582,22583,22584,22585,22586,22587,22588,22589,22590,22591,
22592,22593,22594,22595,22596,22597,22598,22599,22600,22601,22602,22603,
22604,22605,22606,22607,22608,22609,22610,22611,22612,22613,22614,22615,
22616,22617,22618,22619,22620,22621,22622,22623,22624,22625,22626,22627,
22628,22629,22630,22631,22632,22633,22634,22635,22636,22637,22638,22639,
22640,22641,22642,22643,22644,22645,22646,22647,22648,22649,22650,22651,
22652,22653,22654,22655,22656,22657,22658,22659,22660,22661,22662,22663,
22664,22665,22666,22667,22668,22669,22670,22671,22672,22673,22674,22675,
22676,22677,22678,22679,22680,22681,22682,22683,22684,22685,22686,22687,
22688,22689,22690,22691,22692,22693,22694,22695,22696,22697,22698,22699,
22700,22701,22702,22703,22704,22705,22706,22707,22708,22709,22710,22711,
22712,22713,22714,22715,22716,22717,22718,22719,22720,22721,22722,22723,
22724,22725,22726,22727,22728,22729,22730,22731,22732,22733,22734,22735,
22736,22737,22738,22739,22740,22741,22742,22743,22744,22745,22746,22747,
22748,22749,22750,22751,22752,22753,22754,22755,22756,22757,22758,22759,
22760,22761,22762,22763,22764,22765,22766,22767,22768,22769,22770,22771,
22772,22773,22774,22775,22776,22777,22778,22779,22780,22781,22782,22783,
22784,22785,22786,22787,22788,22789,22790,22791,22792,22793,22794,22795,
22796,22797,22798,22799,22800,22801,22802,22803,22804,22805,22806,22807,
22808,22809,22810,22811,22812,22813,22814,22815,22816,22817,22818,22819,
22820,22821,22822,22823,22824,22825,22826,22827,22828,22829,22830,22831,
22832,22833,22834,22835,22836,22837,22838,22839,22840,22841,22842,22843,
22844,22845,22846,22847,22848,22849,22850,22851,22852,22853,22854,22855,
22856,22857,22858,22859,22860,22861,22862,22863,22864,22865,22866,22867,
22868,22869,22870,22871,22872,22873,22874,22875,22876,22877,22878,22879,
22880,22881,22882,22883,22884,22885,22886,22887,22888,22889,22890,22891,
22892,22893,22894,22895,22896,22897,22898,22899,22900,22901,22902,22903,
22904,22905,22906,22907,22908,22909,22910,22911,22912,22913,22914,22915,
22916,22917,22918,22919,22920,22921,22922,22923,22924,22925,22926,22927,
22928,22929,22930,22931,22932,22933,22934,22935,22936,22937,22938,22939,
22940,22941,22942,22943,22944,22945,22946,22947,22948,22949,22950,22951,
22952,22953,22954,22955,22956,22957,22958,22959,22960,22961,22962,22963,
22964,22965,22966,22967,22968,22969,22970,22971,22972,22973,22974,22975,
22976,22977,22978,22979,22980,22981,22982,22983,22984,22985,22986,22987,
22988,22989,22990,22991,22992,22993,22994,22995,22996,22997,22998,22999,
23000,23001,23002,23003,23004,23005,23006,23007,23008,23009,23010,23011,
23012,23013,23014,23015,23016,23017,23018,23019,23020,23021,23022,23023,
23024,23025,23026,23027,23028,23029,23030,23031,23032,23033,23034,23035,
23036,23037,23038,23039,23040,23041,23042,23043,23044,23045,23046,23047,
23048,23049,23050,23051,23052,23053,23054,23055,23056,23057,23058,23059,
23060,23061,23062,23063,23064,23065,23066,23067,23068,23069,23070,23071,
23072,23073,23074,23075,23076,23077,23078,23079,23080,23081,23082,23083,
23084,23085,23086,23087,23088,23089,23090,23091,23092,23093,23094,23095,
23096,23097,23098,23099,23100,23101,23102,23103,23104,23105,23106,23107,
23108,23109,23110,23111,23112,23113,23114,23115,23116,23117,23118,23119,
23120,23121,23122,23123,23124,23125,23126,23127,23128,23129,23130,23131,
23132,23133,23134,23135,23136,23137,23138,23139,23140,23141,23142,23143,
23144,23145,23146,23147,23148,23149,23150,23151,23152,23153,23154,23155,
23156,23157,23158,23159,23160,23161,23162,23163,23164,23165,23166,23167,
23168,23169,23170,23171,23172,23173,23174,23175,23176,23177,23178,23179,
23180,23181,23182,23183,23184,23185,23186,23187,23188,23189,23190,23191,
23192,23193,23194,23195,23196,23197,23198,23199,23200,23201,23202,23203,
23204,23205,23206,23207,23208,23209,23210,23211,23212,23213,23214,23215,
23216,23217,23218,23219,23220,23221,23222,23223,23224,23225,23226,23227,
23228,23229,23230,23231,23232,23233,23234,23235,23236,23237,23238,23239,
23240,23241,23242,23243,23244,23245,23246,23247,23248,23249,23250,23251,
23252,23253,23254,23255,23256,23257,23258,23259,23260,23261,23262,23263,
23264,23265,23266,23267,23268,23269,23270,23271,23272,23273,23274,23275,
23276,23277,23278,23279,23280,23281,23282,23283,23284,23285,23286,23287,
23288,23289,23290,23291,23292,23293,23294,23295,23296,23297,23298,23299,
23300,23301,23302,23303,23304,23305,23306,23307,23308,23309,23310,23311,
23312,23313,23314,23315,23316,23317,23318,23319,23320,23321,23322,23323,
23324,23325,23326,23327,23328,23329,23330,23331,23332,23333,23334,23335,
23336,23337,23338,23339,23340,23341,23342,23343,23344,23345,23346,23347,
23348,23349,23350,23351,23352,23353,23354,23355,23356,23357,23358,23359,
23360,23361,23362,23363,23364,23365,23366,23367,23368,23369,23370,23371,
23372,23373,23374,23375,23376,23377,23378,23379,23380,23381,23382,23383,
23384,23385,23386,23387,23388,23389,23390,23391,23392,23393,23394,23395,
23396,23397,23398,23399,23400,23401,23402,23403,23404,23405,23406,23407,
23408,23409,23410,23411,23412,23413,23414,23415,23416,23417,23418,23419,
23420,23421,23422,23423,23424,23425,23426,23427,23428,23429,23430,23431,
23432,23433,23434,23435,23436,23437,23438,23439,23440,23441,23442,23443,
23444,23445,23446,23447,23448,23449,23450,23451,23452,23453,23454,23455,
23456,23457,23458,23459,23460,23461,23462,23463,23464,23465,23466,23467,
23468,23469,23470,23471,23472,23473,23474,23475,23476,23477,23478,23479,
23480,23481,23482,23483,23484,23485,23486,23487,23488,23489,23490,23491,
23492,23493,23494,23495,23496,23497,23498,23499,23500,23501,23502,23503,
23504,23505,23506,23507,23508,23509,23510,23511,23512,23513,23514,23515,
23516,23517,23518,23519,23520,23521,23522,23523,23524,23525,23526,23527,
23528,23529,23530,23531,23532,23533,23534,23535,23536,23537,23538,23539,
23540,23541,23542,23543,23544,23545,23546,23547,23548,23549,23550,23551,
23552,23553,23554,23555,23556,23557,23558,23559,23560,23561,23562,23563,
23564,23565,23566,23567,23568,23569,23570,23571,23572,23573,23574,23575,
23576,23577,23578,23579,23580,23581,23582,23583,23584,23585,23586,23587,
23588,23589,23590,23591,23592,23593,23594,23595,23596,23597,23598,23599,
23600,23601,23602,23603,23604,23605,23606,23607,23608,23609,23610,23611,
23612,23613,23614,23615,23616,23617,23618,23619,23620,23621,23622,23623,
23624,23625,23626,23627,23628,23629,23630,23631,23632,23633,23634,23635,
23636,23637,23638,23639,23640,23641,23642,23643,23644,23645,23646,23647,
23648,23649,23650,23651,23652,23653,23654,23655,23656,23657,23658,23659,
23660,23661,23662,23663,23664,23665,23666,23667,23668,23669,23670,23671,
23672,23673,23674,23675,23676,23677,23678,23679,23680,23681,23682,23683,
23684,23685,23686,23687,23688,23689,23690,23691,23692,23693,23694,23695,
23696,23697,23698,23699,23700,23701,23702,23703,23704,23705,23706,23707,
23708,23709,23710,23711,23712,23713,23714,23715,23716,23717,23718,23719,
23720,23721,23722,23723,23724,23725,23726,23727,23728,23729,23730,23731,
23732,23733,23734,23735,23736,23737,23738,23739,23740,23741,23742,23743,
23744,23745,23746,23747,23748,23749,23750,23751,23752,23753,23754,23755,
23756,23757,23758,23759,23760,23761,23762,23763,23764,23765,23766,23767,
23768,23769,23770,23771,23772,23773,23774,23775,23776,23777,23778,23779,
23780,23781,23782,23783,23784,23785,23786,23787,23788,23789,23790,23791,
23792,23793,23794,23795,23796,23797,23798,23799,23800,23801,23802,23803,
23804,23805,23806,23807,23808,23809,23810,23811,23812,23813,23814,23815,
23816,23817,23818,23819,23820,23821,23822,23823,23824,23825,23826,23827,
23828,23829,23830,23831,23832,23833,23834,23835,23836,23837,23838,23839,
23840,23841,23842,23843,23844,23845,23846,23847,23848,23849,23850,23851,
23852,23853,23854,23855,23856,23857,23858,23859,23860,23861,23862,23863,
23864,23865,23866,23867,23868,23869,23870,23871,23872,23873,23874,23875,
23876,23877,23878,23879,23880,23881,23882,23883,23884,23885,23886,23887,
23888,23889,23890,23891,23892,23893,23894,23895,23896,23897,23898,23899,
23900,23901,23902,23903,23904,23905,23906,23907,23908,23909,23910,23911,
23912,23913,23914,23915,23916,23917,23918,23919,23920,23921,23922,23923,
23924,23925,23926,23927,23928,23929,23930,23931,23932,23933,23934,23935,
23936,23937,23938,23939,23940,23941,23942,23943,23944,23945,23946,23947,
23948,23949,23950,23951,23952,23953,23954,23955,23956,23957,23958,23959,
23960,23961,23962,23963,23964,23965,23966,23967,23968,23969,23970,23971,
23972,23973,23974,23975,23976,23977,23978,23979,23980,23981,23982,23983,
23984,23985,23986,23987,23988,23989,23990,23991,23992,23993,23994,23995,
23996,23997,23998,23999,24000,24001,24002,24003,24004,24005,24006,24007,
24008,24009,24010,24011,24012,24013,24014,24015,24016,24017,24018,24019,
24020,24021,24022,24023,24024,24025,24026,24027,24028,24029,24030,24031,
24032,24033,24034,24035,24036,24037,24038,24039,24040,24041,24042,24043,
24044,24045,24046,24047,24048,24049,24050,24051,24052,24053,24054,24055,
24056,24057,24058,24059,24060,24061,24062,24063,24064,24065,24066,24067,
24068,24069,24070,24071,24072,24073,24074,24075,24076,24077,24078,24079,
24080,24081,24082,24083,24084,24085,24086,24087,24088,24089,24090,24091,
24092,24093,24094,24095,24096,24097,24098,24099,24100,24101,24102,24103,
24104,24105,24106,24107,24108,24109,24110,24111,24112,24113,24114,24115,
24116,24117,24118,24119,24120,24121,24122,24123,24124,24125,24126,24127,
24128,24129,24130,24131,24132,24133,24134,24135,24136,24137,24138,24139,
24140,24141,24142,24143,24144,24145,24146,24147,24148,24149,24150,24151,
24152,24153,24154,24155,24156,24157,24158,24159,24160,24161,24162,24163,
24164,24165,24166,24167,24168,24169,24170,24171,24172,24173,24174,24175,
24176,24177,24178,24179,24180,24181,24182,24183,24184,24185,24186,24187,
24188,24189,24190,24191,24192,24193,24194,24195,24196,24197,24198,24199,
24200,24201,24202,24203,24204,24205,24206,24207,24208,24209,24210,24211,
24212,24213,24214,24215,24216,24217,24218,24219,24220,24221,24222,24223,
24224,24225,24226,24227,24228,24229,24230,24231,24232,24233,24234,24235,
24236,24237,24238,24239,24240,24241,24242,24243,24244,24245,24246,24247,
24248,24249,24250,24251,24252,24253,24254,24255,24256,24257,24258,24259,
24260,24261,24262,24263,24264,24265,24266,24267,24268,24269,24270,24271,
24272,24273,24274,24275,24276,24277,24278,24279,24280,24281,24282,24283,
24284,24285,24286,24287,24288,24289,24290,24291,24292,24293,24294,24295,
24296,24297,24298,24299,24300,24301,24302,24303,24304,24305,24306,24307,
24308,24309,24310,24311,24312,24313,24314,24315,24316,24317,24318,24319,
24320,24321,24322,24323,24324,24325,24326,24327,24328,24329,24330,24331,
24332,24333,24334,24335,24336,24337,24338,24339,24340,24341,24342,24343,
24344,24345,24346,24347,24348,24349,24350,24351,24352,24353,24354,24355,
24356,24357,24358,24359,24360,24361,24362,24363,24364,24365,24366,24367,
24368,24369,24370,24371,24372,24373,24374,24375,24376,24377,24378,24379,
24380,24381,24382,24383,24384,24385,24386,24387,24388,24389,24390,24391,
24392,24393,24394,24395,24396,24397,24398,24399,24400,24401,24402,24403,
24404,24405,24406,24407,24408,24409,24410,24411,24412,24413,24414,24415,
24416,24417,24418,24419,24420,24421,24422,24423,24424,24425,24426,24427,
24428,24429,24430,24431,24432,24433,24434,24435,24436,24437,24438,24439,
24440,24441,24442,24443,24444,24445,24446,24447,24448,24449,24450,24451,
24452,24453,24454,24455,24456,24457,24458,24459,24460,24461,24462,24463,
24464,24465,24466,24467,24468,24469,24470,24471,24472,24473,24474,24475,
24476,24477,24478,24479,24480,24481,24482,24483,24484,24485,24486,24487,
24488,24489,24490,24491,24492,24493,24494,24495,24496,24497,24498,24499,
24500,24501,24502,24503,24504,24505,24506,24507,24508,24509,24510,24511,
24512,24513,24514,24515,24516,24517,24518,24519,24520,24521,24522,24523,
24524,24525,24526,24527,24528,24529,24530,24531,24532,24533,24534,24535,
24536,24537,24538,24539,24540,24541,24542,24543,24544,24545,24546,24547,
24548,24549,24550,24551,24552,24553,24554,24555,24556,24557,24558,24559,
24560,24561,24562,24563,24564,24565,24566,24567,24568,24569,24570,24571,
24572,24573,24574,24575,24576,24577,24578,24579,24580,24581,24582,24583,
24584,24585,24586,24587,24588,24589,24590,24591,24592,24593,24594,24595,
24596,24597,24598,24599,24600,24601,24602,24603,24604,24605,24606,24607,
24608,24609,24610,24611,24612,24613,24614,24615,24616,24617,24618,24619,
24620,24621,24622,24623,24624,24625,24626,24627,24628,24629,24630,24631,
24632,24633,24634,24635,24636,24637,24638,24639,24640,24641,24642,24643,
24644,24645,24646,24647,24648,24649,24650,24651,24652,24653,24654,24655,
24656,24657,24658,24659,24660,24661,24662,24663,24664,24665,24666,24667,
24668,24669,24670,24671,24672,24673,24674,24675,24676,24677,24678,24679,
24680,24681,24682,24683,24684,24685,24686,24687,24688,24689,24690,24691,
24692,24693,24694,24695,24696,24697,24698,24699,24700,24701,24702,24703,
24704,24705,24706,24707,24708,24709,24710,24711,24712,24713,24714,24715,
24716,24717,24718,24719,24720,24721,24722,24723,24724,24725,24726,24727,
24728,24729,24730,24731,24732,24733,24734,24735,24736,24737,24738,24739,
24740,24741,24742,24743,24744,24745,24746,24747,24748,24749,24750,24751,
24752,24753,24754,24755,24756,24757,24758,24759,24760,24761,24762,24763,
24764,24765,24766,24767,24768,24769,24770,24771,24772,24773,24774,24775,
24776,24777,24778,24779,24780,24781,24782,24783,24784,24785,24786,24787,
24788,24789,24790,24791,24792,24793,24794,24795,24796,24797,24798,24799,
24800,24801,24802,24803,24804,24805,24806,24807,24808,24809,24810,24811,
24812,24813,24814,24815,24816,24817,24818,24819,24820,24821,24822,24823,
24824,24825,24826,24827,24828,24829,24830,24831,24832,24833,24834,24835,
24836,24837,24838,24839,24840,24841,24842,24843,24844,24845,24846,24847,
24848,24849,24850,24851,24852,24853,24854,24855,24856,24857,24858,24859,
24860,24861,24862,24863,24864,24865,24866,24867,24868,24869,24870,24871,
24872,24873,24874,24875,24876,24877,24878,24879,24880,24881,24882,24883,
24884,24885,24886,24887,24888,24889,24890,24891,24892,24893,24894,24895,
24896,24897,24898,24899,24900,24901,24902,24903,24904,24905,24906,24907,
24908,24909,24910,24911,24912,24913,24914,24915,24916,24917,24918,24919,
24920,24921,24922,24923,24924,24925,24926,24927,24928,24929,24930,24931,
24932,24933,24934,24935,24936,24937,24938,24939,24940,24941,24942,24943,
24944,24945,24946,24947,24948,24949,24950,24951,24952,24953,24954,24955,
24956,24957,24958,24959,24960,24961,24962,24963,24964,24965,24966,24967,
24968,24969,24970,24971,24972,24973,24974,24975,24976,24977,24978,24979,
24980,24981,24982,24983,24984,24985,24986,24987,24988,24989,24990,24991,
24992,24993,24994,24995,24996,24997,24998,24999,25000,25001,25002,25003,
25004,25005,25006,25007,25008,25009,25010,25011,25012,25013,25014,25015,
25016,25017,25018,25019,25020,25021,25022,25023,25024,25025,25026,25027,
25028,25029,25030,25031,25032,25033,25034,25035,25036,25037,25038,25039,
25040,25041,25042,25043,25044,25045,25046,25047,25048,25049,25050,25051,
25052,25053,25054,25055,25056,25057,25058,25059,25060,25061,25062,25063,
25064,25065,25066,25067,25068,25069,25070,25071,25072,25073,25074,25075,
25076,25077,25078,25079,25080,25081,25082,25083,25084,25085,25086,25087,
25088,25089,25090,25091,25092,25093,25094,25095,25096,25097,25098,25099,
25100,25101,25102,25103,25104,25105,25106,25107,25108,25109,25110,25111,
25112,25113,25114,25115,25116,25117,25118,25119,25120,25121,25122,25123,
25124,25125,25126,25127,25128,25129,25130,25131,25132,25133,25134,25135,
25136,25137,25138,25139,25140,25141,25142,25143,25144,25145,25146,25147,
25148,25149,25150,25151,25152,25153,25154,25155,25156,25157,25158,25159,
25160,25161,25162,25163,25164,25165,25166,25167,25168,25169,25170,25171,
25172,25173,25174,25175,25176,25177,25178,25179,25180,25181,25182,25183,
25184,25185,25186,25187,25188,25189,25190,25191,25192,25193,25194,25195,
25196,25197,25198,25199,25200,25201,25202,25203,25204,25205,25206,25207,
25208,25209,25210,25211,25212,25213,25214,25215,25216,25217,25218,25219,
25220,25221,25222,25223,25224,25225,25226,25227,25228,25229,25230,25231,
25232,25233,25234,25235,25236,25237,25238,25239,25240,25241,25242,25243,
25244,25245,25246,25247,25248,25249,25250,25251,25252,25253,25254,25255,
25256,25257,25258,25259,25260,25261,25262,25263,25264,25265,25266,25267,
25268,25269,25270,25271,25272,25273,25274,25275,25276,25277,25278,25279,
25280,25281,25282,25283,25284,25285,25286,25287,25288,25289,25290,25291,
25292,25293,25294,25295,25296,25297,25298,25299,25300,25301,25302,25303,
25304,25305,25306,25307,25308,25309,25310,25311,25312,25313,25314,25315,
25316,25317,25318,25319,25320,25321,25322,25323,25324,25325,25326,25327,
25328,25329,25330,25331,25332,25333,25334,25335,25336,25337,25338,25339,
25340,25341,25342,25343,25344,25345,25346,25347,25348,25349,25350,25351,
25352,25353,25354,25355,25356,25357,25358,25359,25360,25361,25362,25363,
25364,25365,25366,25367,25368,25369,25370,25371,25372,25373,25374,25375,
25376,25377,25378,25379,25380,25381,25382,25383,25384,25385,25386,25387,
25388,25389,25390,25391,25392,25393,25394,25395,25396,25397,25398,25399,
25400,25401,25402,25403,25404,25405,25406,25407,25408,25409,25410,25411,
25412,25413,25414,25415,25416,25417,25418,25419,25420,25421,25422,25423,
25424,25425,25426,25427,25428,25429,25430,25431,25432,25433,25434,25435,
25436,25437,25438,25439,25440,25441,25442,25443,25444,25445,25446,25447,
25448,25449,25450,25451,25452,25453,25454,25455,25456,25457,25458,25459,
25460,25461,25462,25463,25464,25465,25466,25467,25468,25469,25470,25471,
25472,25473,25474,25475,25476,25477,25478,25479,25480,25481,25482,25483,
25484,25485,25486,25487,25488,25489,25490,25491,25492,25493,25494,25495,
25496,25497,25498,25499,25500,25501,25502,25503,25504,25505,25506,25507,
25508,25509,25510,25511,25512,25513,25514,25515,25516,25517,25518,25519,
25520,25521,25522,25523,25524,25525,25526,25527,25528,25529,25530,25531,
25532,25533,25534,25535,25536,25537,25538,25539,25540,25541,25542,25543,
25544,25545,25546,25547,25548,25549,25550,25551,25552,25553,25554,25555,
25556,25557,25558,25559,25560,25561,25562,25563,25564,25565,25566,25567,
25568,25569,25570,25571,25572,25573,25574,25575,25576,25577,25578,25579,
25580,25581,25582,25583,25584,25585,25586,25587,25588,25589,25590,25591,
25592,25593,25594,25595,25596,25597,25598,25599,25600,25601,25602,25603,
25604,25605,25606,25607,25608,25609,25610,25611,25612,25613,25614,25615,
25616,25617,25618,25619,25620,25621,25622,25623,25624,25625,25626,25627,
25628,25629,25630,25631,25632,25633,25634,25635,25636,25637,25638,25639,
25640,25641,25642,25643,25644,25645,25646,25647,25648,25649,25650,25651,
25652,25653,25654,25655,25656,25657,25658,25659,25660,25661,25662,25663,
25664,25665,25666,25667,25668,25669,25670,25671,25672,25673,25674,25675,
25676,25677,25678,25679,25680,25681,25682,25683,25684,25685,25686,25687,
25688,25689,25690,25691,25692,25693,25694,25695,25696,25697,25698,25699,
25700,25701,25702,25703,25704,25705,25706,25707,25708,25709,25710,25711,
25712,25713,25714,25715,25716,25717,25718,25719,25720,25721,25722,25723,
25724,25725,25726,25727,25728,25729,25730,25731,25732,25733,25734,25735,
25736,25737,25738,25739,25740,25741,25742,25743,25744,25745,25746,25747,
25748,25749,25750,25751,25752,25753,25754,25755,25756,25757,25758,25759,
25760,25761,25762,25763,25764,25765,25766,25767,25768,25769,25770,25771,
25772,25773,25774,25775,25776,25777,25778,25779,25780,25781,25782,25783,
25784,25785,25786,25787,25788,25789,25790,25791,25792,25793,25794,25795,
25796,25797,25798,25799,25800,25801,25802,25803,25804,25805,25806,25807,
25808,25809,25810,25811,25812,25813,25814,25815,25816,25817,25818,25819,
25820,25821,25822,25823,25824,25825,25826,25827,25828,25829,25830,25831,
25832,25833,25834,25835,25836,25837,25838,25839,25840,25841,25842,25843,
25844,25845,25846,25847,25848,25849,25850,25851,25852,25853,25854,25855,
25856,25857,25858,25859,25860,25861,25862,25863,25864,25865,25866,25867,
25868,25869,25870,25871,25872,25873,25874,25875,25876,25877,25878,25879,
25880,25881,25882,25883,25884,25885,25886,25887,25888,25889,25890,25891,
25892,25893,25894,25895,25896,25897,25898,25899,25900,25901,25902,25903,
25904,25905,25906,25907,25908,25909,25910,25911,25912,25913,25914,25915,
25916,25917,25918,25919,25920,25921,25922,25923,25924,25925,25926,25927,
25928,25929,25930,25931,25932,25933,25934,25935,25936,25937,25938,25939,
25940,25941,25942,25943,25944,25945,25946,25947,25948,25949,25950,25951,
25952,25953,25954,25955,25956,25957,25958,25959,25960,25961,25962,25963,
25964,25965,25966,25967,25968,25969,25970,25971,25972,25973,25974,25975,
25976,25977,25978,25979,25980,25981,25982,25983,25984,25985,25986,25987,
25988,25989,25990,25991,25992,25993,25994,25995,25996,25997,25998,25999,
26000,26001,26002,26003,26004,26005,26006,26007,26008,26009,26010,26011,
26012,26013,26014,26015,26016,26017,26018,26019,26020,26021,26022,26023,
26024,26025,26026,26027,26028,26029,26030,26031,26032,26033,26034,26035,
26036,26037,26038,26039,26040,26041,26042,26043,26044,26045,26046,26047,
26048,26049,26050,26051,26052,26053,26054,26055,26056,26057,26058,26059,
26060,26061,26062,26063,26064,26065,26066,26067,26068,26069,26070,26071,
26072,26073,26074,26075,26076,26077,26078,26079,26080,26081,26082,26083,
26084,26085,26086,26087,26088,26089,26090,26091,26092,26093,26094,26095,
26096,26097,26098,26099,26100,26101,26102,26103,26104,26105,26106,26107,
26108,26109,26110,26111,26112,26113,26114,26115,26116,26117,26118,26119,
26120,26121,26122,26123,26124,26125,26126,26127,26128,26129,26130,26131,
26132,26133,26134,26135,26136,26137,26138,26139,26140,26141,26142,26143,
26144,26145,26146,26147,26148,26149,26150,26151,26152,26153,26154,26155,
26156,26157,26158,26159,26160,26161,26162,26163,26164,26165,26166,26167,
26168,26169,26170,26171,26172,26173,26174,26175,26176,26177,26178,26179,
26180,26181,26182,26183,26184,26185,26186,26187,26188,26189,26190,26191,
26192,26193,26194,26195,26196,26197,26198,26199,26200,26201,26202,26203,
26204,26205,26206,26207,26208,26209,26210,26211,26212,26213,26214,26215,
26216,26217,26218,26219,26220,26221,26222,26223,26224,26225,26226,26227,
26228,26229,26230,26231,26232,26233,26234,26235,26236,26237,26238,26239,
26240,26241,26242,26243,26244,26245,26246,26247,26248,26249,26250,26251,
26252,26253,26254,26255,26256,26257,26258,26259,26260,26261,26262,26263,
26264,26265,26266,26267,26268,26269,26270,26271,26272,26273,26274,26275,
26276,26277,26278,26279,26280,26281,26282,26283,26284,26285,26286,26287,
26288,26289,26290,26291,26292,26293,26294,26295,26296,26297,26298,26299,
26300,26301,26302,26303,26304,26305,26306,26307,26308,26309,26310,26311,
26312,26313,26314,26315,26316,26317,26318,26319,26320,26321,26322,26323,
26324,26325,26326,26327,26328,26329,26330,26331,26332,26333,26334,26335,
26336,26337,26338,26339,26340,26341,26342,26343,26344,26345,26346,26347,
26348,26349,26350,26351,26352,26353,26354,26355,26356,26357,26358,26359,
26360,26361,26362,26363,26364,26365,26366,26367,26368,26369,26370,26371,
26372,26373,26374,26375,26376,26377,26378,26379,26380,26381,26382,26383,
26384,26385,26386,26387,26388,26389,26390,26391,26392,26393,26394,26395,
26396,26397,26398,26399,26400,26401,26402,26403,26404,26405,26406,26407,
26408,26409,26410,26411,26412,26413,26414,26415,26416,26417,26418,26419,
26420,26421,26422,26423,26424,26425,26426,26427,26428,26429,26430,26431,
26432,26433,26434,26435,26436,26437,26438,26439,26440,26441,26442,26443,
26444,26445,26446,26447,26448,26449,26450,26451,26452,26453,26454,26455,
26456,26457,26458,26459,26460,26461,26462,26463,26464,26465,26466,26467,
26468,26469,26470,26471,26472,26473,26474,26475,26476,26477,26478,26479,
26480,26481,26482,26483,26484,26485,26486,26487,26488,26489,26490,26491,
26492,26493,26494,26495,26496,26497,26498,26499,26500,26501,26502,26503,
26504,26505,26506,26507,26508,26509,26510,26511,26512,26513,26514,26515,
26516,26517,26518,26519,26520,26521,26522,26523,26524,26525,26526,26527,
26528,26529,26530,26531,26532,26533,26534,26535,26536,26537,26538,26539,
26540,26541,26542,26543,26544,26545,26546,26547,26548,26549,26550,26551,
26552,26553,26554,26555,26556,26557,26558,26559,26560,26561,26562,26563,
26564,26565,26566,26567,26568,26569,26570,26571,26572,26573,26574,26575,
26576,26577,26578,26579,26580,26581,26582,26583,26584,26585,26586,26587,
26588,26589,26590,26591,26592,26593,26594,26595,26596,26597,26598,26599,
26600,26601,26602,26603,26604,26605,26606,26607,26608,26609,26610,26611,
26612,26613,26614,26615,26616,26617,26618,26619,26620,26621,26622,26623,
26624,26625,26626,26627,26628,26629,26630,26631,26632,26633,26634,26635,
26636,26637,26638,26639,26640,26641,26642,26643,26644,26645,26646,26647,
26648,26649,26650,26651,26652,26653,26654,26655,26656,26657,26658,26659,
26660,26661,26662,26663,26664,26665,26666,26667,26668,26669,26670,26671,
26672,26673,26674,26675,26676,26677,26678,26679,26680,26681,26682,26683,
26684,26685,26686,26687,26688,26689,26690,26691,26692,26693,26694,26695,
26696,26697,26698,26699,26700,26701,26702,26703,26704,26705,26706,26707,
26708,26709,26710,26711,26712,26713,26714,26715,26716,26717,26718,26719,
26720,26721,26722,26723,26724,26725,26726,26727,26728,26729,26730,26731,
26732,26733,26734,26735,26736,26737,26738,26739,26740,26741,26742,26743,
26744,26745,26746,26747,26748,26749,26750,26751,26752,26753,26754,26755,
26756,26757,26758,26759,26760,26761,26762,26763,26764,26765,26766,26767,
26768,26769,26770,26771,26772,26773,26774,26775,26776,26777,26778,26779,
26780,26781,26782,26783,26784,26785,26786,26787,26788,26789,26790,26791,
26792,26793,26794,26795,26796,26797,26798,26799,26800,26801,26802,26803,
26804,26805,26806,26807,26808,26809,26810,26811,26812,26813,26814,26815,
26816,26817,26818,26819,26820,26821,26822,26823,26824,26825,26826,26827,
26828,26829,26830,26831,26832,26833,26834,26835,26836,26837,26838,26839,
26840,26841,26842,26843,26844,26845,26846,26847,26848,26849,26850,26851,
26852,26853,26854,26855,26856,26857,26858,26859,26860,26861,26862,26863,
26864,26865,26866,26867,26868,26869,26870,26871,26872,26873,26874,26875,
26876,26877,26878,26879,26880,26881,26882,26883,26884,26885,26886,26887,
26888,26889,26890,26891,26892,26893,26894,26895,26896,26897,26898,26899,
26900,26901,26902,26903,26904,26905,26906,26907,26908,26909,26910,26911,
26912,26913,26914,26915,26916,26917,26918,26919,26920,26921,26922,26923,
26924,26925,26926,26927,26928,26929,26930,26931,26932,26933,26934,26935,
26936,26937,26938,26939,26940,26941,26942,26943,26944,26945,26946,26947,
26948,26949,26950,26951,26952,26953,26954,26955,26956,26957,26958,26959,
26960,26961,26962,26963,26964,26965,26966,26967,26968,26969,26970,26971,
26972,26973,26974,26975,26976,26977,26978,26979,26980,26981,26982,26983,
26984,26985,26986,26987,26988,26989,26990,26991,26992,26993,26994,26995,
26996,26997,26998,26999,27000,27001,27002,27003,27004,27005,27006,27007,
27008,27009,27010,27011,27012,27013,27014,27015,27016,27017,27018,27019,
27020,27021,27022,27023,27024,27025,27026,27027,27028,27029,27030,27031,
27032,27033,27034,27035,27036,27037,27038,27039,27040,27041,27042,27043,
27044,27045,27046,27047,27048,27049,27050,27051,27052,27053,27054,27055,
27056,27057,27058,27059,27060,27061,27062,27063,27064,27065,27066,27067,
27068,27069,27070,27071,27072,27073,27074,27075,27076,27077,27078,27079,
27080,27081,27082,27083,27084,27085,27086,27087,27088,27089,27090,27091,
27092,27093,27094,27095,27096,27097,27098,27099,27100,27101,27102,27103,
27104,27105,27106,27107,27108,27109,27110,27111,27112,27113,27114,27115,
27116,27117,27118,27119,27120,27121,27122,27123,27124,27125,27126,27127,
27128,27129,27130,27131,27132,27133,27134,27135,27136,27137,27138,27139,
27140,27141,27142,27143,27144,27145,27146,27147,27148,27149,27150,27151,
27152,27153,27154,27155,27156,27157,27158,27159,27160,27161,27162,27163,
27164,27165,27166,27167,27168,27169,27170,27171,27172,27173,27174,27175,
27176,27177,27178,27179,27180,27181,27182,27183,27184,27185,27186,27187,
27188,27189,27190,27191,27192,27193,27194,27195,27196,27197,27198,27199,
27200,27201,27202,27203,27204,27205,27206,27207,27208,27209,27210,27211,
27212,27213,27214,27215,27216,27217,27218,27219,27220,27221,27222,27223,
27224,27225,27226,27227,27228,27229,27230,27231,27232,27233,27234,27235,
27236,27237,27238,27239,27240,27241,27242,27243,27244,27245,27246,27247,
27248,27249,27250,27251,27252,27253,27254,27255,27256,27257,27258,27259,
27260,27261,27262,27263,27264,27265,27266,27267,27268,27269,27270,27271,
27272,27273,27274,27275,27276,27277,27278,27279,27280,27281,27282,27283,
27284,27285,27286,27287,27288,27289,27290,27291,27292,27293,27294,27295,
27296,27297,27298,27299,27300,27301,27302,27303,27304,27305,27306,27307,
27308,27309,27310,27311,27312,27313,27314,27315,27316,27317,27318,27319,
27320,27321,27322,27323,27324,27325,27326,27327,27328,27329,27330,27331,
27332,27333,27334,27335,27336,27337,27338,27339,27340,27341,27342,27343,
27344,27345,27346,27347,27348,27349,27350,27351,27352,27353,27354,27355,
27356,27357,27358,27359,27360,27361,27362,27363,27364,27365,27366,27367,
27368,27369,27370,27371,27372,27373,27374,27375,27376,27377,27378,27379,
27380,27381,27382,27383,27384,27385,27386,27387,27388,27389,27390,27391,
27392,27393,27394,27395,27396,27397,27398,27399,27400,27401,27402,27403,
27404,27405,27406,27407,27408,27409,27410,27411,27412,27413,27414,27415,
27416,27417,27418,27419,27420,27421,27422,27423,27424,27425,27426,27427,
27428,27429,27430,27431,27432,27433,27434,27435,27436,27437,27438,27439,
27440,27441,27442,27443,27444,27445,27446,27447,27448,27449,27450,27451,
27452,27453,27454,27455,27456,27457,27458,27459,27460,27461,27462,27463,
27464,27465,27466,27467,27468,27469,27470,27471,27472,27473,27474,27475,
27476,27477,27478,27479,27480,27481,27482,27483,27484,27485,27486,27487,
27488,27489,27490,27491,27492,27493,27494,27495,27496,27497,27498,27499,
27500,27501,27502,27503,27504,27505,27506,27507,27508,27509,27510,27511,
27512,27513,27514,27515,27516,27517,27518,27519,27520,27521,27522,27523,
27524,27525,27526,27527,27528,27529,27530,27531,27532,27533,27534,27535,
27536,27537,27538,27539,27540,27541,27542,27543,27544,27545,27546,27547,
27548,27549,27550,27551,27552,27553,27554,27555,27556,27557,27558,27559,
27560,27561,27562,27563,27564,27565,27566,27567,27568,27569,27570,27571,
27572,27573,27574,27575,27576,27577,27578,27579,27580,27581,27582,27583,
27584,27585,27586,27587,27588,27589,27590,27591,27592,27593,27594,27595,
27596,27597,27598,27599,27600,27601,27602,27603,27604,27605,27606,27607,
27608,27609,27610,27611,27612,27613,27614,27615,27616,27617,27618,27619,
27620,27621,27622,27623,27624,27625,27626,27627,27628,27629,27630,27631,
27632,27633,27634,27635,27636,27637,27638,27639,27640,27641,27642,27643,
27644,27645,27646,27647,27648,27649,27650,27651,27652,27653,27654,27655,
27656,27657,27658,27659,27660,27661,27662,27663,27664,27665,27666,27667,
27668,27669,27670,27671,27672,27673,27674,27675,27676,27677,27678,27679,
27680,27681,27682,27683,27684,27685,27686,27687,27688,27689,27690,27691,
27692,27693,27694,27695,27696,27697,27698,27699,27700,27701,27702,27703,
27704,27705,27706,27707,27708,27709,27710,27711,27712,27713,27714,27715,
27716,27717,27718,27719,27720,27721,27722,27723,27724,27725,27726,27727,
27728,27729,27730,27731,27732,27733,27734,27735,27736,27737,27738,27739,
27740,27741,27742,27743,27744,27745,27746,27747,27748,27749,27750,27751,
27752,27753,27754,27755,27756,27757,27758,27759,27760,27761,27762,27763,
27764,27765,27766,27767,27768,27769,27770,27771,27772,27773,27774,27775,
27776,27777,27778,27779,27780,27781,27782,27783,27784,27785,27786,27787,
27788,27789,27790,27791,27792,27793,27794,27795,27796,27797,27798,27799,
27800,27801,27802,27803,27804,27805,27806,27807,27808,27809,27810,27811,
27812,27813,27814,27815,27816,27817,27818,27819,27820,27821,27822,27823,
27824,27825,27826,27827,27828,27829,27830,27831,27832,27833,27834,27835,
27836,27837,27838,27839,27840,27841,27842,27843,27844,27845,27846,27847,
27848,27849,27850,27851,27852,27853,27854,27855,27856,27857,27858,27859,
27860,27861,27862,27863,27864,27865,27866,27867,27868,27869,27870,27871,
27872,27873,27874,27875,27876,27877,27878,27879,27880,27881,27882,27883,
27884,27885,27886,27887,27888,27889,27890,27891,27892,27893,27894,27895,
27896,27897,27898,27899,27900,27901,27902,27903,27904,27905,27906,27907,
27908,27909,27910,27911,27912,27913,27914,27915,27916,27917,27918,27919,
27920,27921,27922,27923,27924,27925,27926,27927,27928,27929,27930,27931,
27932,27933,27934,27935,27936,27937,27938,27939,27940,27941,27942,27943,
27944,27945,27946,27947,27948,27949,27950,27951,27952,27953,27954,27955,
27956,27957,27958,27959,27960,27961,27962,27963,27964,27965,27966,27967,
27968,27969,27970,27971,27972,27973,27974,27975,27976,27977,27978,27979,
27980,27981,27982,27983,27984,27985,27986,27987,27988,27989,27990,27991,
27992,27993,27994,27995,27996,27997,27998,27999,28000,28001,28002,28003,
28004,28005,28006,28007,28008,28009,28010,28011,28012,28013,28014,28015,
28016,28017,28018,28019,28020,28021,28022,28023,28024,28025,28026,28027,
28028,28029,28030,28031,28032,28033,28034,28035,28036,28037,28038,28039,
28040,28041,28042,28043,28044,28045,28046,28047,28048,28049,28050,28051,
28052,28053,28054,28055,28056,28057,28058,28059,28060,28061,28062,28063,
28064,28065,28066,28067,28068,28069,28070,28071,28072,28073,28074,28075,
28076,28077,28078,28079,28080,28081,28082,28083,28084,28085,28086,28087,
28088,28089,28090,28091,28092,28093,28094,28095,28096,28097,28098,28099,
28100,28101,28102,28103,28104,28105,28106,28107,28108,28109,28110,28111,
28112,28113,28114,28115,28116,28117,28118,28119,28120,28121,28122,28123,
28124,28125,28126,28127,28128,28129,28130,28131,28132,28133,28134,28135,
28136,28137,28138,28139,28140,28141,28142,28143,28144,28145,28146,28147,
28148,28149,28150,28151,28152,28153,28154,28155,28156,28157,28158,28159,
28160,28161,28162,28163,28164,28165,28166,28167,28168,28169,28170,28171,
28172,28173,28174,28175,28176,28177,28178,28179,28180,28181,28182,28183,
28184,28185,28186,28187,28188,28189,28190,28191,28192,28193,28194,28195,
28196,28197,28198,28199,28200,28201,28202,28203,28204,28205,28206,28207,
28208,28209,28210,28211,28212,28213,28214,28215,28216,28217,28218,28219,
28220,28221,28222,28223,28224,28225,28226,28227,28228,28229,28230,28231,
28232,28233,28234,28235,28236,28237,28238,28239,28240,28241,28242,28243,
28244,28245,28246,28247,28248,28249,28250,28251,28252,28253,28254,28255,
28256,28257,28258,28259,28260,28261,28262,28263,28264,28265,28266,28267,
28268,28269,28270,28271,28272,28273,28274,28275,28276,28277,28278,28279,
28280,28281,28282,28283,28284,28285,28286,28287,28288,28289,28290,28291,
28292,28293,28294,28295,28296,28297,28298,28299,28300,28301,28302,28303,
28304,28305,28306,28307,28308,28309,28310,28311,28312,28313,28314,28315,
28316,28317,28318,28319,28320,28321,28322,28323,28324,28325,28326,28327,
28328,28329,28330,28331,28332,28333,28334,28335,28336,28337,28338,28339,
28340,28341,28342,28343,28344,28345,28346,28347,28348,28349,28350,28351,
28352,28353,28354,28355,28356,28357,28358,28359,28360,28361,28362,28363,
28364,28365,28366,28367,28368,28369,28370,28371,28372,28373,28374,28375,
28376,28377,28378,28379,28380,28381,28382,28383,28384,28385,28386,28387,
28388,28389,28390,28391,28392,28393,28394,28395,28396,28397,28398,28399,
28400,28401,28402,28403,28404,28405,28406,28407,28408,28409,28410,28411,
28412,28413,28414,28415,28416,28417,28418,28419,28420,28421,28422,28423,
28424,28425,28426,28427,28428,28429,28430,28431,28432,28433,28434,28435,
28436,28437,28438,28439,28440,28441,28442,28443,28444,28445,28446,28447,
28448,28449,28450,28451,28452,28453,28454,28455,28456,28457,28458,28459,
28460,28461,28462,28463,28464,28465,28466,28467,28468,28469,28470,28471,
28472,28473,28474,28475,28476,28477,28478,28479,28480,28481,28482,28483,
28484,28485,28486,28487,28488,28489,28490,28491,28492,28493,28494,28495,
28496,28497,28498,28499,28500,28501,28502,28503,28504,28505,28506,28507,
28508,28509,28510,28511,28512,28513,28514,28515,28516,28517,28518,28519,
28520,28521,28522,28523,28524,28525,28526,28527,28528,28529,28530,28531,
28532,28533,28534,28535,28536,28537,28538,28539,28540,28541,28542,28543,
28544,28545,28546,28547,28548,28549,28550,28551,28552,28553,28554,28555,
28556,28557,28558,28559,28560,28561,28562,28563,28564,28565,28566,28567,
28568,28569,28570,28571,28572,28573,28574,28575,28576,28577,28578,28579,
28580,28581,28582,28583,28584,28585,28586,28587,28588,28589,28590,28591,
28592,28593,28594,28595,28596,28597,28598,28599,28600,28601,28602,28603,
28604,28605,28606,28607,28608,28609,28610,28611,28612,28613,28614,28615,
28616,28617,28618,28619,28620,28621,28622,28623,28624,28625,28626,28627,
28628,28629,28630,28631,28632,28633,28634,28635,28636,28637,28638,28639,
28640,28641,28642,28643,28644,28645,28646,28647,28648,28649,28650,28651,
28652,28653,28654,28655,28656,28657,28658,28659,28660,28661,28662,28663,
28664,28665,28666,28667,28668,28669,28670,28671,28672,28673,28674,28675,
28676,28677,28678,28679,28680,28681,28682,28683,28684,28685,28686,28687,
28688,28689,28690,28691,28692,28693,28694,28695,28696,28697,28698,28699,
28700,28701,28702,28703,28704,28705,28706,28707,28708,28709,28710,28711,
28712,28713,28714,28715,28716,28717,28718,28719,28720,28721,28722,28723,
28724,28725,28726,28727,28728,28729,28730,28731,28732,28733,28734,28735,
28736,28737,28738,28739,28740,28741,28742,28743,28744,28745,28746,28747,
28748,28749,28750,28751,28752,28753,28754,28755,28756,28757,28758,28759,
28760,28761,28762,28763,28764,28765,28766,28767,28768,28769,28770,28771,
28772,28773,28774,28775,28776,28777,28778,28779,28780,28781,28782,28783,
28784,28785,28786,28787,28788,28789,28790,28791,28792,28793,28794,28795,
28796,28797,28798,28799,28800,28801,28802,28803,28804,28805,28806,28807,
28808,28809,28810,28811,28812,28813,28814,28815,28816,28817,28818,28819,
28820,28821,28822,28823,28824,28825,28826,28827,28828,28829,28830,28831,
28832,28833,28834,28835,28836,28837,28838,28839,28840,28841,28842,28843,
28844,28845,28846,28847,28848,28849,28850,28851,28852,28853,28854,28855,
28856,28857,28858,28859,28860,28861,28862,28863,28864,28865,28866,28867,
28868,28869,28870,28871,28872,28873,28874,28875,28876,28877,28878,28879,
28880,28881,28882,28883,28884,28885,28886,28887,28888,28889,28890,28891,
28892,28893,28894,28895,28896,28897,28898,28899,28900,28901,28902,28903,
28904,28905,28906,28907,28908,28909,28910,28911,28912,28913,28914,28915,
28916,28917,28918,28919,28920,28921,28922,28923,28924,28925,28926,28927,
28928,28929,28930,28931,28932,28933,28934,28935,28936,28937,28938,28939,
28940,28941,28942,28943,28944,28945,28946,28947,28948,28949,28950,28951,
28952,28953,28954,28955,28956,28957,28958,28959,28960,28961,28962,28963,
28964,28965,28966,28967,28968,28969,28970,28971,28972,28973,28974,28975,
28976,28977,28978,28979,28980,28981,28982,28983,28984,28985,28986,28987,
28988,28989,28990,28991,28992,28993,28994,28995,28996,28997,28998,28999,
29000,29001,29002,29003,29004,29005,29006,29007,29008,29009,29010,29011,
29012,29013,29014,29015,29016,29017,29018,29019,29020,29021,29022,29023,
29024,29025,29026,29027,29028,29029,29030,29031,29032,29033,29034,29035,
29036,29037,29038,29039,29040,29041,29042,29043,29044,29045,29046,29047,
29048,29049,29050,29051,29052,29053,29054,29055,29056,29057,29058,29059,
29060,29061,29062,29063,29064,29065,29066,29067,29068,29069,29070,29071,
29072,29073,29074,29075,29076,29077,29078,29079,29080,29081,29082,29083,
29084,29085,29086,29087,29088,29089,29090,29091,29092,29093,29094,29095,
29096,29097,29098,29099,29100,29101,29102,29103,29104,29105,29106,29107,
29108,29109,29110,29111,29112,29113,29114,29115,29116,29117,29118,29119,
29120,29121,29122,29123,29124,29125,29126,29127,29128,29129,29130,29131,
29132,29133,29134,29135,29136,29137,29138,29139,29140,29141,29142,29143,
29144,29145,29146,29147,29148,29149,29150,29151,29152,29153,29154,29155,
29156,29157,29158,29159,29160,29161,29162,29163,29164,29165,29166,29167,
29168,29169,29170,29171,29172,29173,29174,29175,29176,29177,29178,29179,
29180,29181,29182,29183,29184,29185,29186,29187,29188,29189,29190,29191,
29192,29193,29194,29195,29196,29197,29198,29199,29200,29201,29202,29203,
29204,29205,29206,29207,29208,29209,29210,29211,29212,29213,29214,29215,
29216,29217,29218,29219,29220,29221,29222,29223,29224,29225,29226,29227,
29228,29229,29230,29231,29232,29233,29234,29235,29236,29237,29238,29239,
29240,29241,29242,29243,29244,29245,29246,29247,29248,29249,29250,29251,
29252,29253,29254,29255,29256,29257,29258,29259,29260,29261,29262,29263,
29264,29265,29266,29267,29268,29269,29270,29271,29272,29273,29274,29275,
29276,29277,29278,29279,29280,29281,29282,29283,29284,29285,29286,29287,
29288,29289,29290,29291,29292,29293,29294,29295,29296,29297,29298,29299,
29300,29301,29302,29303,29304,29305,29306,29307,29308,29309,29310,29311,
29312,29313,29314,29315,29316,29317,29318,29319,29320,29321,29322,29323,
29324,29325,29326,29327,29328,29329,29330,29331,29332,29333,29334,29335,
29336,29337,29338,29339,29340,29341,29342,29343,29344,29345,29346,29347,
29348,29349,29350,29351,29352,29353,29354,29355,29356,29357,29358,29359,
29360,29361,29362,29363,29364,29365,29366,29367,29368,29369,29370,29371,
29372,29373,29374,29375,29376,29377,29378,29379,29380,29381,29382,29383,
29384,29385,29386,29387,29388,29389,29390,29391,29392,29393,29394,29395,
29396,29397,29398,29399,29400,29401,29402,29403,29404,29405,29406,29407,
29408,29409,29410,29411,29412,29413,29414,29415,29416,29417,29418,29419,
29420,29421,29422,29423,29424,29425,29426,29427,29428,29429,29430,29431,
29432,29433,29434,29435,29436,29437,29438,29439,29440,29441,29442,29443,
29444,29445,29446,29447,29448,29449,29450,29451,29452,29453,29454,29455,
29456,29457,29458,29459,29460,29461,29462,29463,29464,29465,29466,29467,
29468,29469,29470,29471,29472,29473,29474,29475,29476,29477,29478,29479,
29480,29481,29482,29483,29484,29485,29486,29487,29488,29489,29490,29491,
29492,29493,29494,29495,29496,29497,29498,29499,29500,29501,29502,29503,
29504,29505,29506,29507,29508,29509,29510,29511,29512,29513,29514,29515,
29516,29517,29518,29519,29520,29521,29522,29523,29524,29525,29526,29527,
29528,29529,29530,29531,29532,29533,29534,29535,29536,29537,29538,29539,
29540,29541,29542,29543,29544,29545,29546,29547,29548,29549,29550,29551,
29552,29553,29554,29555,29556,29557,29558,29559,29560,29561,29562,29563,
29564,29565,29566,29567,29568,29569,29570,29571,29572,29573,29574,29575,
29576,29577,29578,29579,29580,29581,29582,29583,29584,29585,29586,29587,
29588,29589,29590,29591,29592,29593,29594,29595,29596,29597,29598,29599,
29600,29601,29602,29603,29604,29605,29606,29607,29608,29609,29610,29611,
29612,29613,29614,29615,29616,29617,29618,29619,29620,29621,29622,29623,
29624,29625,29626,29627,29628,29629,29630,29631,29632,29633,29634,29635,
29636,29637,29638,29639,29640,29641,29642,29643,29644,29645,29646,29647,
29648,29649,29650,29651,29652,29653,29654,29655,29656,29657,29658,29659,
29660,29661,29662,29663,29664,29665,29666,29667,29668,29669,29670,29671,
29672,29673,29674,29675,29676,29677,29678,29679,29680,29681,29682,29683,
29684,29685,29686,29687,29688,29689,29690,29691,29692,29693,29694,29695,
29696,29697,29698,29699,29700,29701,29702,29703,29704,29705,29706,29707,
29708,29709,29710,29711,29712,29713,29714,29715,29716,29717,29718,29719,
29720,29721,29722,29723,29724,29725,29726,29727,29728,29729,29730,29731,
29732,29733,29734,29735,29736,29737,29738,29739,29740,29741,29742,29743,
29744,29745,29746,29747,29748,29749,29750,29751,29752,29753,29754,29755,
29756,29757,29758,29759,29760,29761,29762,29763,29764,29765,29766,29767,
29768,29769,29770,29771,29772,29773,29774,29775,29776,29777,29778,29779,
29780,29781,29782,29783,29784,29785,29786,29787,29788,29789,29790,29791,
29792,29793,29794,29795,29796,29797,29798,29799,29800,29801,29802,29803,
29804,29805,29806,29807,29808,29809,29810,29811,29812,29813,29814,29815,
29816,29817,29818,29819,29820,29821,29822,29823,29824,29825,29826,29827,
29828,29829,29830,29831,29832,29833,29834,29835,29836,29837,29838,29839,
29840,29841,29842,29843,29844,29845,29846,29847,29848,29849,29850,29851,
29852,29853,29854,29855,29856,29857,29858,29859,29860,29861,29862,29863,
29864,29865,29866,29867,29868,29869,29870,29871,29872,29873,29874,29875,
29876,29877,29878,29879,29880,29881,29882,29883,29884,29885,29886,29887,
29888,29889,29890,29891,29892,29893,29894,29895,29896,29897,29898,29899,
29900,29901,29902,29903,29904,29905,29906,29907,29908,29909,29910,29911,
29912,29913,29914,29915,29916,29917,29918,29919,29920,29921,29922,29923,
29924,29925,29926,29927,29928,29929,29930,29931,29932,29933,29934,29935,
29936,29937,29938,29939,29940,29941,29942,29943,29944,29945,29946,29947,
29948,29949,29950,29951,29952,29953,29954,29955,29956,29957,29958,29959,
29960,29961,29962,29963,29964,29965,29966,29967,29968,29969,29970,29971,
29972,29973,29974,29975,29976,29977,29978,29979,29980,29981,29982,29983,
29984,29985,29986,29987,29988,29989,29990,29991,29992,29993,29994,29995,
29996,29997,29998,29999,30000,30001,30002,30003,30004,30005,30006,30007,
30008,30009,30010,30011,30012,30013,30014,30015,30016,30017,30018,30019,
30020,30021,30022,30023,30024,30025,30026,30027,30028,30029,30030,30031,
30032,30033,30034,30035,30036,30037,30038,30039,30040,30041,30042,30043,
30044,30045,30046,30047,30048,30049,30050,30051,30052,30053,30054,30055,
30056,30057,30058,30059,30060,30061,30062,30063,30064,30065,30066,30067,
30068,30069,30070,30071,30072,30073,30074,30075,30076,30077,30078,30079,
30080,30081,30082,30083,30084,30085,30086,30087,30088,30089,30090,30091,
30092,30093,30094,30095,30096,30097,30098,30099,30100,30101,30102,30103,
30104,30105,30106,30107,30108,30109,30110,30111,30112,30113,30114,30115,
30116,30117,30118,30119,30120,30121,30122,30123,30124,30125,30126,30127,
30128,30129,30130,30131,30132,30133,30134,30135,30136,30137,30138,30139,
30140,30141,30142,30143,30144,30145,30146,30147,30148,30149,30150,30151,
30152,30153,30154,30155,30156,30157,30158,30159,30160,30161,30162,30163,
30164,30165,30166,30167,30168,30169,30170,30171,30172,30173,30174,30175,
30176,30177,30178,30179,30180,30181,30182,30183,30184,30185,30186,30187,
30188,30189,30190,30191,30192,30193,30194,30195,30196,30197,30198,30199,
30200,30201,30202,30203,30204,30205,30206,30207,30208,30209,30210,30211,
30212,30213,30214,30215,30216,30217,30218,30219,30220,30221,30222,30223,
30224,30225,30226,30227,30228,30229,30230,30231,30232,30233,30234,30235,
30236,30237,30238,30239,30240,30241,30242,30243,30244,30245,30246,30247,
30248,30249,30250,30251,30252,30253,30254,30255,30256,30257,30258,30259,
30260,30261,30262,30263,30264,30265,30266,30267,30268,30269,30270,30271,
30272,30273,30274,30275,30276,30277,30278,30279,30280,30281,30282,30283,
30284,30285,30286,30287,30288,30289,30290,30291,30292,30293,30294,30295,
30296,30297,30298,30299,30300,30301,30302,30303,30304,30305,30306,30307,
30308,30309,30310,30311,30312,30313,30314,30315,30316,30317,30318,30319,
30320,30321,30322,30323,30324,30325,30326,30327,30328,30329,30330,30331,
30332,30333,30334,30335,30336,30337,30338,30339,30340,30341,30342,30343,
30344,30345,30346,30347,30348,30349,30350,30351,30352,30353,30354,30355,
30356,30357,30358,30359,30360,30361,30362,30363,30364,30365,30366,30367,
30368,30369,30370,30371,30372,30373,30374,30375,30376,30377,30378,30379,
30380,30381,30382,30383,30384,30385,30386,30387,30388,30389,30390,30391,
30392,30393,30394,30395,30396,30397,30398,30399,30400,30401,30402,30403,
30404,30405,30406,30407,30408,30409,30410,30411,30412,30413,30414,30415,
30416,30417,30418,30419,30420,30421,30422,30423,30424,30425,30426,30427,
30428,30429,30430,30431,30432,30433,30434,30435,30436,30437,30438,30439,
30440,30441,30442,30443,30444,30445,30446,30447,30448,30449,30450,30451,
30452,30453,30454,30455,30456,30457,30458,30459,30460,30461,30462,30463,
30464,30465,30466,30467,30468,30469,30470,30471,30472,30473,30474,30475,
30476,30477,30478,30479,30480,30481,30482,30483,30484,30485,30486,30487,
30488,30489,30490,30491,30492,30493,30494,30495,30496,30497,30498,30499,
30500,30501,30502,30503,30504,30505,30506,30507,30508,30509,30510,30511,
30512,30513,30514,30515,30516,30517,30518,30519,30520,30521,30522,30523,
30524,30525,30526,30527,30528,30529,30530,30531,30532,30533,30534,30535,
30536,30537,30538,30539,30540,30541,30542,30543,30544,30545,30546,30547,
30548,30549,30550,30551,30552,30553,30554,30555,30556,30557,30558,30559,
30560,30561,30562,30563,30564,30565,30566,30567,30568,30569,30570,30571,
30572,30573,30574,30575,30576,30577,30578,30579,30580,30581,30582,30583,
30584,30585,30586,30587,30588,30589,30590,30591,30592,30593,30594,30595,
30596,30597,30598,30599,30600,30601,30602,30603,30604,30605,30606,30607,
30608,30609,30610,30611,30612,30613,30614,30615,30616,30617,30618,30619,
30620,30621,30622,30623,30624,30625,30626,30627,30628,30629,30630,30631,
30632,30633,30634,30635,30636,30637,30638,30639,30640,30641,30642,30643,
30644,30645,30646,30647,30648,30649,30650,30651,30652,30653,30654,30655,
30656,30657,30658,30659,30660,30661,30662,30663,30664,30665,30666,30667,
30668,30669,30670,30671,30672,30673,30674,30675,30676,30677,30678,30679,
30680,30681,30682,30683,30684,30685,30686,30687,30688,30689,30690,30691,
30692,30693,30694,30695,30696,30697,30698,30699,30700,30701,30702,30703,
30704,30705,30706,30707,30708,30709,30710,30711,30712,30713,30714,30715,
30716,30717,30718,30719,30720,30721,30722,30723,30724,30725,30726,30727,
30728,30729,30730,30731,30732,30733,30734,30735,30736,30737,30738,30739,
30740,30741,30742,30743,30744,30745,30746,30747,30748,30749,30750,30751,
30752,30753,30754,30755,30756,30757,30758,30759,30760,30761,30762,30763,
30764,30765,30766,30767,30768,30769,30770,30771,30772,30773,30774,30775,
30776,30777,30778,30779,30780,30781,30782,30783,30784,30785,30786,30787,
30788,30789,30790,30791,30792,30793,30794,30795,30796,30797,30798,30799,
30800,30801,30802,30803,30804,30805,30806,30807,30808,30809,30810,30811,
30812,30813,30814,30815,30816,30817,30818,30819,30820,30821,30822,30823,
30824,30825,30826,30827,30828,30829,30830,30831,30832,30833,30834,30835,
30836,30837,30838,30839,30840,30841,30842,30843,30844,30845,30846,30847,
30848,30849,30850,30851,30852,30853,30854,30855,30856,30857,30858,30859,
30860,30861,30862,30863,30864,30865,30866,30867,30868,30869,30870,30871,
30872,30873,30874,30875,30876,30877,30878,30879,30880,30881,30882,30883,
30884,30885,30886,30887,30888,30889,30890,30891,30892,30893,30894,30895,
30896,30897,30898,30899,30900,30901,30902,30903,30904,30905,30906,30907,
30908,30909,30910,30911,30912,30913,30914,30915,30916,30917,30918,30919,
30920,30921,30922,30923,30924,30925,30926,30927,30928,30929,30930,30931,
30932,30933,30934,30935,30936,30937,30938,30939,30940,30941,30942,30943,
30944,30945,30946,30947,30948,30949,30950,30951,30952,30953,30954,30955,
30956,30957,30958,30959,30960,30961,30962,30963,30964,30965,30966,30967,
30968,30969,30970,30971,30972,30973,30974,30975,30976,30977,30978,30979,
30980,30981,30982,30983,30984,30985,30986,30987,30988,30989,30990,30991,
30992,30993,30994,30995,30996,30997,30998,30999,31000,31001,31002,31003,
31004,31005,31006,31007,31008,31009,31010,31011,31012,31013,31014,31015,
31016,31017,31018,31019,31020,31021,31022,31023,31024,31025,31026,31027,
31028,31029,31030,31031,31032,31033,31034,31035,31036,31037,31038,31039,
31040,31041,31042,31043,31044,31045,31046,31047,31048,31049,31050,31051,
31052,31053,31054,31055,31056,31057,31058,31059,31060,31061,31062,31063,
31064,31065,31066,31067,31068,31069,31070,31071,31072,31073,31074,31075,
31076,31077,31078,31079,31080,31081,31082,31083,31084,31085,31086,31087,
31088,31089,31090,31091,31092,31093,31094,31095,31096,31097,31098,31099,
31100,31101,31102,31103,31104,31105,31106,31107,31108,31109,31110,31111,
31112,31113,31114,31115,31116,31117,31118,31119,31120,31121,31122,31123,
31124,31125,31126,31127,31128,31129,31130,31131,31132,31133,31134,31135,
31136,31137,31138,31139,31140,31141,31142,31143,31144,31145,31146,31147,
31148,31149,31150,31151,31152,31153,31154,31155,31156,31157,31158,31159,
31160,31161,31162,31163,31164,31165,31166,31167,31168,31169,31170,31171,
31172,31173,31174,31175,31176,31177,31178,31179,31180,31181,31182,31183,
31184,31185,31186,31187,31188,31189,31190,31191,31192,31193,31194,31195,
31196,31197,31198,31199,31200,31201,31202,31203,31204,31205,31206,31207,
31208,31209,31210,31211,31212,31213,31214,31215,31216,31217,31218,31219,
31220,31221,31222,31223,31224,31225,31226,31227,31228,31229,31230,31231,
31232,31233,31234,31235,31236,31237,31238,31239,31240,31241,31242,31243,
31244,31245,31246,31247,31248,31249,31250,31251,31252,31253,31254,31255,
31256,31257,31258,31259,31260,31261,31262,31263,31264,31265,31266,31267,
31268,31269,31270,31271,31272,31273,31274,31275,31276,31277,31278,31279,
31280,31281,31282,31283,31284,31285,31286,31287,31288,31289,31290,31291,
31292,31293,31294,31295,31296,31297,31298,31299,31300,31301,31302,31303,
31304,31305,31306,31307,31308,31309,31310,31311,31312,31313,31314,31315,
31316,31317,31318,31319,31320,31321,31322,31323,31324,31325,31326,31327,
31328,31329,31330,31331,31332,31333,31334,31335,31336,31337,31338,31339,
31340,31341,31342,31343,31344,31345,31346,31347,31348,31349,31350,31351,
31352,31353,31354,31355,31356,31357,31358,31359,31360,31361,31362,31363,
31364,31365,31366,31367,31368,31369,31370,31371,31372,31373,31374,31375,
31376,31377,31378,31379,31380,31381,31382,31383,31384,31385,31386,31387,
31388,31389,31390,31391,31392,31393,31394,31395,31396,31397,31398,31399,
31400,31401,31402,31403,31404,31405,31406,31407,31408,31409,31410,31411,
31412,31413,31414,31415,31416,31417,31418,31419,31420,31421,31422,31423,
31424,31425,31426,31427,31428,31429,31430,31431,31432,31433,31434,31435,
31436,31437,31438,31439,31440,31441,31442,31443,31444,31445,31446,31447,
31448,31449,31450,31451,31452,31453,31454,31455,31456,31457,31458,31459,
31460,31461,31462,31463,31464,31465,31466,31467,31468,31469,31470,31471,
31472,31473,31474,31475,31476,31477,31478,31479,31480,31481,31482,31483,
31484,31485,31486,31487,31488,31489,31490,31491,31492,31493,31494,31495,
31496,31497,31498,31499,31500,31501,31502,31503,31504,31505,31506,31507,
31508,31509,31510,31511,31512,31513,31514,31515,31516,31517,31518,31519,
31520,31521,31522,31523,31524,31525,31526,31527,31528,31529,31530,31531,
31532,31533,31534,31535,31536,31537,31538,31539,31540,31541,31542,31543,
31544,31545,31546,31547,31548,31549,31550,31551,31552,31553,31554,31555,
31556,31557,31558,31559,31560,31561,31562,31563,31564,31565,31566,31567,
31568,31569,31570,31571,31572,31573,31574,31575,31576,31577,31578,31579,
31580,31581,31582,31583,31584,31585,31586,31587,31588,31589,31590,31591,
31592,31593,31594,31595,31596,31597,31598,31599,31600,31601,31602,31603,
31604,31605,31606,31607,31608,31609,31610,31611,31612,31613,31614,31615,
31616,31617,31618,31619,31620,31621,31622,31623,31624,31625,31626,31627,
31628,31629,31630,31631,31632,31633,31634,31635,31636,31637,31638,31639,
31640,31641,31642,31643,31644,31645,31646,31647,31648,31649,31650,31651,
31652,31653,31654,31655,31656,31657,31658,31659,31660,31661,31662,31663,
31664,31665,31666,31667,31668,31669,31670,31671,31672,31673,31674,31675,
31676,31677,31678,31679,31680,31681,31682,31683,31684,31685,31686,31687,
31688,31689,31690,31691,31692,31693,31694,31695,31696,31697,31698,31699,
31700,31701,31702,31703,31704,31705,31706,31707,31708,31709,31710,31711,
31712,31713,31714,31715,31716,31717,31718,31719,31720,31721,31722,31723,
31724,31725,31726,31727,31728,31729,31730,31731,31732,31733,31734,31735,
31736,31737,31738,31739,31740,31741,31742,31743,31744,31745,31746,31747,
31748,31749,31750,31751,31752,31753,31754,31755,31756,31757,31758,31759,
31760,31761,31762,31763,31764,31765,31766,31767,31768,31769,31770,31771,
31772,31773,31774,31775,31776,31777,31778,31779,31780,31781,31782,31783,
31784,31785,31786,31787,31788,31789,31790,31791,31792,31793,31794,31795,
31796,31797,31798,31799,31800,31801,31802,31803,31804,31805,31806,31807,
31808,31809,31810,31811,31812,31813,31814,31815,31816,31817,31818,31819,
31820,31821,31822,31823,31824,31825,31826,31827,31828,31829,31830,31831,
31832,31833,31834,31835,31836,31837,31838,31839,31840,31841,31842,31843,
31844,31845,31846,31847,31848,31849,31850,31851,31852,31853,31854,31855,
31856,31857,31858,31859,31860,31861,31862,31863,31864,31865,31866,31867,
31868,31869,31870,31871,31872,31873,31874,31875,31876,31877,31878,31879,
31880,31881,31882,31883,31884,31885,31886,31887,31888,31889,31890,31891,
31892,31893,31894,31895,31896,31897,31898,31899,31900,31901,31902,31903,
31904,31905,31906,31907,31908,31909,31910,31911,31912,31913,31914,31915,
31916,31917,31918,31919,31920,31921,31922,31923,31924,31925,31926,31927,
31928,31929,31930,31931,31932,31933,31934,31935,31936,31937,31938,31939,
31940,31941,31942,31943,31944,31945,31946,31947,31948,31949,31950,31951,
31952,31953,31954,31955,31956,31957,31958,31959,31960,31961,31962,31963,
31964,31965,31966,31967,31968,31969,31970,31971,31972,31973,31974,31975,
31976,31977,31978,31979,31980,31981,31982,31983,31984,31985,31986,31987,
31988,31989,31990,31991,31992,31993,31994,31995,31996,31997,31998,31999,
32000,32001,32002,32003,32004,32005,32006,32007,32008,32009,32010,32011,
32012,32013,32014,32015,32016,32017,32018,32019,32020,32021,32022,32023,
32024,32025,32026,32027,32028,32029,32030,32031,32032,32033,32034,32035,
32036,32037,32038,32039,32040,32041,32042,32043,32044,32045,32046,32047,
32048,32049,32050,32051,32052,32053,32054,32055,32056,32057,32058,32059,
32060,32061,32062,32063,32064,32065,32066,32067,32068,32069,32070,32071,
32072,32073,32074,32075,32076,32077,32078,32079,32080,32081,32082,32083,
32084,32085,32086,32087,32088,32089,32090,32091,32092,32093,32094,32095,
32096,32097,32098,32099,32100,32101,32102,32103,32104,32105,32106,32107,
32108,32109,32110,32111,32112,32113,32114,32115,32116,32117,32118,32119,
32120,32121,32122,32123,32124,32125,32126,32127,32128,32129,32130,32131,
32132,32133,32134,32135,32136,32137,32138,32139,32140,32141,32142,32143,
32144,32145,32146,32147,32148,32149,32150,32151,32152,32153,32154,32155,
32156,32157,32158,32159,32160,32161,32162,32163,32164,32165,32166,32167,
32168,32169,32170,32171,32172,32173,32174,32175,32176,32177,32178,32179,
32180,32181,32182,32183,32184,32185,32186,32187,32188,32189,32190,32191,
32192,32193,32194,32195,32196,32197,32198,32199,32200,32201,32202,32203,
32204,32205,32206,32207,32208,32209,32210,32211,32212,32213,32214,32215,
32216,32217,32218,32219,32220,32221,32222,32223,32224,32225,32226,32227,
32228,32229,32230,32231,32232,32233,32234,32235,32236,32237,32238,32239,
32240,32241,32242,32243,32244,32245,32246,32247,32248,32249,32250,32251,
32252,32253,32254,32255,32256,32257,32258,32259,32260,32261,32262,32263,
32264,32265,32266,32267,32268,32269,32270,32271,32272,32273,32274,32275,
32276,32277,32278,32279,32280,32281,32282,32283,32284,32285,32286,32287,
32288,32289,32290,32291,32292,32293,32294,32295,32296,32297,32298,32299,
32300,32301,32302,32303,32304,32305,32306,32307,32308,32309,32310,32311,
32312,32313,32314,32315,32316,32317,32318,32319,32320,32321,32322,32323,
32324,32325,32326,32327,32328,32329,32330,32331,32332,32333,32334,32335,
32336,32337,32338,32339,32340,32341,32342,32343,32344,32345,32346,32347,
32348,32349,32350,32351,32352,32353,32354,32355,32356,32357,32358,32359,
32360,32361,32362,32363,32364,32365,32366,32367,32368,32369,32370,32371,
32372,32373,32374,32375,32376,32377,32378,32379,32380,32381,32382,32383,
32384,32385,32386,32387,32388,32389,32390,32391,32392,32393,32394,32395,
32396,32397,32398,32399,32400,32401,32402,32403,32404,32405,32406,32407,
32408,32409,32410,32411,32412,32413,32414,32415,32416,32417,32418,32419,
32420,32421,32422,32423,32424,32425,32426,32427,32428,32429,32430,32431,
32432,32433,32434,32435,32436,32437,32438,32439,32440,32441,32442,32443,
32444,32445,32446,32447,32448,32449,32450,32451,32452,32453,32454,32455,
32456,32457,32458,32459,32460,32461,32462,32463,32464,32465,32466,32467,
32468,32469,32470,32471,32472,32473,32474,32475,32476,32477,32478,32479,
32480,32481,32482,32483,32484,32485,32486,32487,32488,32489,32490,32491,
32492,32493,32494,32495,32496,32497,32498,32499,32500,32501,32502,32503,
32504,32505,32506,32507,32508,32509,32510,32511,32512,32513,32514,32515,
32516,32517,32518,32519,32520,32521,32522,32523,32524,32525,32526,32527,
32528,32529,32530,32531,32532,32533,32534,32535,32536,32537,32538,32539,
32540,32541,32542,32543,32544,32545,32546,32547,32548,32549,32550,32551,
32552,32553,32554,32555,32556,32557,32558,32559,32560,32561,32562,32563,
32564,32565,32566,32567,32568,32569,32570,32571,32572,32573,32574,32575,
32576,32577,32578,32579,32580,32581,32582,32583,32584,32585,32586,32587,
32588,32589,32590,32591,32592,32593,32594,32595,32596,32597,32598,32599,
32600,32601,32602,32603,32604,32605,32606,32607,32608,32609,32610,32611,
32612,32613,32614,32615,32616,32617,32618,32619,32620,32621,32622,32623,
32624,32625,32626,32627,32628,32629,32630,32631,32632,32633,32634,32635,
32636,32637,32638,32639,32640,32641,32642,32643,32644,32645,32646,32647,
32648,32649,32650,32651,32652,32653,32654,32655,32656,32657,32658,32659,
32660,32661,32662,32663,32664,32665,32666,32667,32668,32669,32670,32671,
32672,32673,32674,32675,32676,32677,32678,32679,32680,32681,32682,32683,
32684,32685,32686,32687,32688,32689,32690,32691,32692,32693,32694,32695,
32696,32697,32698,32699,32700,32701,32702,32703,32704,32705,32706,32707,
32708,32709,32710,32711,32712,32713,32714,32715,32716,32717,32718,32719,
32720,32721,32722,32723,32724,32725,32726,32727,32728,32729,32730,32731,
32732,32733,32734,32735,32736,32737,32738,32739,32740,32741,32742,32743,
32744,32745,32746,32747,32748,32749,32750,32751,32752,32753,32754,32755,
32756,32757,32758,32759,32760,32761,32762,32763,32764,32765,32766,32767,
32768L,32769L,32770L,32771L,32772L,32773L,32774L,32775L,32776L,32777L,
32778L,32779L,32780L,32781L,32782L,32783L,32784L,32785L,32786L,32787L,
32788L,32789L,32790L,32791L,32792L,32793L,32794L,32795L,32796L,32797L,
32798L,32799L,32800L,32801L,32802L,32803L,32804L,32805L,32806L,32807L,
32808L,32809L,32810L,32811L,32812L,32813L,32814L,32815L,32816L,32817L,
32818L,32819L,32820L,32821L,32822L,32823L,32824L,32825L,32826L,32827L,
32828L,32829L,32830L,32831L,32832L,32833L,32834L,32835L,32836L,32837L,
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33298L,33299L,33300L,33301L,33302L,33303L,33304L,33305L,33306L,33307L,
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33318L,33319L,33320L,33321L,33322L,33323L,33324L,33325L,33326L,33327L,
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33388L,33389L,33390L,33391L,33392L,33393L,33394L,33395L,33396L,33397L,
33398L,33399L,33400L,33401L,33402L,33403L,33404L,33405L,33406L,33407L,
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33448L,33449L,33450L,33451L,33452L,33453L,33454L,33455L,33456L,33457L,
33458L,33459L,33460L,33461L,33462L,33463L,33464L,33465L,33466L,33467L,
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33518L,33519L,33520L,33521L,33522L,33523L,33524L,33525L,33526L,33527L,
33528L,33529L,33530L,33531L,33532L,33533L,33534L,33535L,33536L,33537L,
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33548L,33549L,33550L,33551L,33552L,33553L,33554L,33555L,33556L,33557L,
33558L,33559L,33560L,33561L,33562L,33563L,33564L,33565L,33566L,33567L,
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33588L,33589L,33590L,33591L,33592L,33593L,33594L,33595L,33596L,33597L,
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33618L,33619L,33620L,33621L,33622L,33623L,33624L,33625L,33626L,33627L,
33628L,33629L,33630L,33631L,33632L,33633L,33634L,33635L,33636L,33637L,
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33718L,33719L,33720L,33721L,33722L,33723L,33724L,33725L,33726L,33727L,
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33768L,33769L,33770L,33771L,33772L,33773L,33774L,33775L,33776L,33777L,
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34068L,34069L,34070L,34071L,34072L,34073L,34074L,34075L,34076L,34077L,
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34088L,34089L,34090L,34091L,34092L,34093L,34094L,34095L,34096L,34097L,
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34228L,34229L,34230L,34231L,34232L,34233L,34234L,34235L,34236L,34237L,
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34318L,34319L,34320L,34321L,34322L,34323L,34324L,34325L,34326L,34327L,
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34388L,34389L,34390L,34391L,34392L,34393L,34394L,34395L,34396L,34397L,
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34418L,34419L,34420L,34421L,34422L,34423L,34424L,34425L,34426L,34427L,
34428L,34429L,34430L,34431L,34432L,34433L,34434L,34435L,34436L,34437L,
34438L,34439L,34440L,34441L,34442L,34443L,34444L,34445L,34446L,34447L,
34448L,34449L,34450L,34451L,34452L,34453L,34454L,34455L,34456L,34457L,
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34468L,34469L,34470L,34471L,34472L,34473L,34474L,34475L,34476L,34477L,
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34498L,34499L,34500L,34501L,34502L,34503L,34504L,34505L,34506L,34507L,
34508L,34509L,34510L,34511L,34512L,34513L,34514L,34515L,34516L,34517L,
34518L,34519L,34520L,34521L,34522L,34523L,34524L,34525L,34526L,34527L,
34528L,34529L,34530L,34531L,34532L,34533L,34534L,34535L,34536L,34537L,
34538L,34539L,34540L,34541L,34542L,34543L,34544L,34545L,34546L,34547L,
34548L,34549L,34550L,34551L,34552L,34553L,34554L,34555L,34556L,34557L,
34558L,34559L,34560L,34561L,34562L,34563L,34564L,34565L,34566L,34567L,
34568L,34569L,34570L,34571L,34572L,34573L,34574L,34575L,34576L,34577L,
34578L,34579L,34580L,34581L,34582L,34583L,34584L,34585L,34586L,34587L,
34588L,34589L,34590L,34591L,34592L,34593L,34594L,34595L,34596L,34597L,
34598L,34599L,34600L,34601L,34602L,34603L,34604L,34605L,34606L,34607L,
34608L,34609L,34610L,34611L,34612L,34613L,34614L,34615L,34616L,34617L,
34618L,34619L,34620L,34621L,34622L,34623L,34624L,34625L,34626L,34627L,
34628L,34629L,34630L,34631L,34632L,34633L,34634L,34635L,34636L,34637L,
34638L,34639L,34640L,34641L,34642L,34643L,34644L,34645L,34646L,34647L,
34648L,34649L,34650L,34651L,34652L,34653L,34654L,34655L,34656L,34657L,
34658L,34659L,34660L,34661L,34662L,34663L,34664L,34665L,34666L,34667L,
34668L,34669L,34670L,34671L,34672L,34673L,34674L,34675L,34676L,34677L,
34678L,34679L,34680L,34681L,34682L,34683L,34684L,34685L,34686L,34687L,
34688L,34689L,34690L,34691L,34692L,34693L,34694L,34695L,34696L,34697L,
34698L,34699L,34700L,34701L,34702L,34703L,34704L,34705L,34706L,34707L,
34708L,34709L,34710L,34711L,34712L,34713L,34714L,34715L,34716L,34717L,
34718L,34719L,34720L,34721L,34722L,34723L,34724L,34725L,34726L,34727L,
34728L,34729L,34730L,34731L,34732L,34733L,34734L,34735L,34736L,34737L,
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34748L,34749L,34750L,34751L,34752L,34753L,34754L,34755L,34756L,34757L,
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36468L,36469L,36470L,36471L,36472L,36473L,36474L,36475L,36476L,36477L,
36478L,36479L,36480L,36481L,36482L,36483L,36484L,36485L,36486L,36487L,
36488L,36489L,36490L,36491L,36492L,36493L,36494L,36495L,36496L,36497L,
36498L,36499L,36500L,36501L,36502L,36503L,36504L,36505L,36506L,36507L,
36508L,36509L,36510L,36511L,36512L,36513L,36514L,36515L,36516L,36517L,
36518L,36519L,36520L,36521L,36522L,36523L,36524L,36525L,36526L,36527L,
36528L,36529L,36530L,36531L,36532L,36533L,36534L,36535L,36536L,36537L,
36538L,36539L,36540L,36541L,36542L,36543L,36544L,36545L,36546L,36547L,
36548L,36549L,36550L,36551L,36552L,36553L,36554L,36555L,36556L,36557L,
36558L,36559L,36560L,36561L,36562L,36563L,36564L,36565L,36566L,36567L,
36568L,36569L,36570L,36571L,36572L,36573L,36574L,36575L,36576L,36577L,
36578L,36579L,36580L,36581L,36582L,36583L,36584L,36585L,36586L,36587L,
36588L,36589L,36590L,36591L,36592L,36593L,36594L,36595L,36596L,36597L,
36598L,36599L,36600L,36601L,36602L,36603L,36604L,36605L,36606L,36607L,
36608L,36609L,36610L,36611L,36612L,36613L,36614L,36615L,36616L,36617L,
36618L,36619L,36620L,36621L,36622L,36623L,36624L,36625L,36626L,36627L,
36628L,36629L,36630L,36631L,36632L,36633L,36634L,36635L,36636L,36637L,
36638L,36639L,36640L,36641L,36642L,36643L,36644L,36645L,36646L,36647L,
36648L,36649L,36650L,36651L,36652L,36653L,36654L,36655L,36656L,36657L,
36658L,36659L,36660L,36661L,36662L,36663L,36664L,36665L,36666L,36667L,
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36678L,36679L,36680L,36681L,36682L,36683L,36684L,36685L,36686L,36687L,
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38298L,38299L,38300L,38301L,38302L,38303L,38304L,38305L,38306L,38307L,
38308L,38309L,38310L,38311L,38312L,38313L,38314L,38315L,38316L,38317L,
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38388L,38389L,38390L,38391L,38392L,38393L,38394L,38395L,38396L,38397L,
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38408L,38409L,38410L,38411L,38412L,38413L,38414L,38415L,38416L,38417L,
38418L,38419L,38420L,38421L,38422L,38423L,38424L,38425L,38426L,38427L,
38428L,38429L,38430L,38431L,38432L,38433L,38434L,38435L,38436L,38437L,
38438L,38439L,38440L,38441L,38442L,38443L,38444L,38445L,38446L,38447L,
38448L,38449L,38450L,38451L,38452L,38453L,38454L,38455L,38456L,38457L,
38458L,38459L,38460L,38461L,38462L,38463L,38464L,38465L,38466L,38467L,
38468L,38469L,38470L,38471L,38472L,38473L,38474L,38475L,38476L,38477L,
38478L,38479L,38480L,38481L,38482L,38483L,38484L,38485L,38486L,38487L,
38488L,38489L,38490L,38491L,38492L,38493L,38494L,38495L,38496L,38497L,
38498L,38499L,38500L,38501L,38502L,38503L,38504L,38505L,38506L,38507L,
38508L,38509L,38510L,38511L,38512L,38513L,38514L,38515L,38516L,38517L,
38518L,38519L,38520L,38521L,38522L,38523L,38524L,38525L,38526L,38527L,
38528L,38529L,38530L,38531L,38532L,38533L,38534L,38535L,38536L,38537L,
38538L,38539L,38540L,38541L,38542L,38543L,38544L,38545L,38546L,38547L,
38548L,38549L,38550L,38551L,38552L,38553L,38554L,38555L,38556L,38557L,
38558L,38559L,38560L,38561L,38562L,38563L,38564L,38565L,38566L,38567L,
38568L,38569L,38570L,38571L,38572L,38573L,38574L,38575L,38576L,38577L,
38578L,38579L,38580L,38581L,38582L,38583L,38584L,38585L,38586L,38587L,
38588L,38589L,38590L,38591L,38592L,38593L,38594L,38595L,38596L,38597L,
38598L,38599L,38600L,38601L,38602L,38603L,38604L,38605L,38606L,38607L,
38608L,38609L,38610L,38611L,38612L,38613L,38614L,38615L,38616L,38617L,
38618L,38619L,38620L,38621L,38622L,38623L,38624L,38625L,38626L,38627L,
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40518L,40519L,40520L,40521L,40522L,40523L,40524L,40525L,40526L,40527L,
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40538L,40539L,40540L,40541L,40542L,40543L,40544L,40545L,40546L,40547L,
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41578L,41579L,41580L,41581L,41582L,41583L,41584L,41585L,41586L,41587L,
41588L,41589L,41590L,41591L,41592L,41593L,41594L,41595L,41596L,41597L,
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41738L,41739L,41740L,41741L,41742L,41743L,41744L,41745L,41746L,41747L,
41748L,41749L,41750L,41751L,41752L,41753L,41754L,41755L,41756L,41757L,
41758L,41759L,41760L,41761L,41762L,41763L,41764L,41765L,41766L,41767L,
41768L,41769L,41770L,41771L,41772L,41773L,41774L,41775L,41776L,41777L,
41778L,41779L,41780L,41781L,41782L,41783L,41784L,41785L,41786L,41787L,
41788L,41789L,41790L,41791L,41792L,41793L,41794L,41795L,41796L,41797L,
41798L,41799L,41800L,41801L,41802L,41803L,41804L,41805L,41806L,41807L,
41808L,41809L,41810L,41811L,41812L,41813L,41814L,41815L,41816L,41817L,
41818L,41819L,41820L,41821L,41822L,41823L,41824L,41825L,41826L,41827L,
41828L,41829L,41830L,41831L,41832L,41833L,41834L,41835L,41836L,41837L,
41838L,41839L,41840L,41841L,41842L,41843L,41844L,41845L,41846L,41847L,
41848L,41849L,41850L,41851L,41852L,41853L,41854L,41855L,41856L,41857L,
41858L,41859L,41860L,41861L,41862L,41863L,41864L,41865L,41866L,41867L,
41868L,41869L,41870L,41871L,41872L,41873L,41874L,41875L,41876L,41877L,
41878L,41879L,41880L,41881L,41882L,41883L,41884L,41885L,41886L,41887L,
41888L,41889L,41890L,41891L,41892L,41893L,41894L,41895L,41896L,41897L,
41898L,41899L,41900L,41901L,41902L,41903L,41904L,41905L,41906L,41907L,
41908L,41909L,41910L,41911L,41912L,41913L,41914L,41915L,41916L,41917L,
41918L,41919L,41920L,41921L,41922L,41923L,41924L,41925L,41926L,41927L,
41928L,41929L,41930L,41931L,41932L,41933L,41934L,41935L,41936L,41937L,
41938L,41939L,41940L,41941L,41942L,41943L,41944L,41945L,41946L,41947L,
41948L,41949L,41950L,41951L,41952L,41953L,41954L,41955L,41956L,41957L,
41958L,41959L,41960L,41961L,41962L,41963L,41964L,41965L,41966L,41967L,
41968L,41969L,41970L,41971L,41972L,41973L,41974L,41975L,41976L,41977L,
41978L,41979L,41980L,41981L,41982L,41983L,41984L,41985L,41986L,41987L,
41988L,41989L,41990L,41991L,41992L,41993L,41994L,41995L,41996L,41997L,
41998L,41999L,42000L,42001L,42002L,42003L,42004L,42005L,42006L,42007L,
42008L,42009L,42010L,42011L,42012L,42013L,42014L,42015L,42016L,42017L,
42018L,42019L,42020L,42021L,42022L,42023L,42024L,42025L,42026L,42027L,
42028L,42029L,42030L,42031L,42032L,42033L,42034L,42035L,42036L,42037L,
42038L,42039L,42040L,42041L,42042L,42043L,42044L,42045L,42046L,42047L,
42048L,42049L,42050L,42051L,42052L,42053L,42054L,42055L,42056L,42057L,
42058L,42059L,42060L,42061L,42062L,42063L,42064L,42065L,42066L,42067L,
42068L,42069L,42070L,42071L,42072L,42073L,42074L,42075L,42076L,42077L,
42078L,42079L,42080L,42081L,42082L,42083L,42084L,42085L,42086L,42087L,
42088L,42089L,42090L,42091L,42092L,42093L,42094L,42095L,42096L,42097L,
42098L,42099L,42100L,42101L,42102L,42103L,42104L,42105L,42106L,42107L,
42108L,42109L,42110L,42111L,42112L,42113L,42114L,42115L,42116L,42117L,
42118L,42119L,42120L,42121L,42122L,42123L,42124L,42125L,42126L,42127L,
42128L,42129L,42130L,42131L,42132L,42133L,42134L,42135L,42136L,42137L,
42138L,42139L,42140L,42141L,42142L,42143L,42144L,42145L,42146L,42147L,
42148L,42149L,42150L,42151L,42152L,42153L,42154L,42155L,42156L,42157L,
42158L,42159L,42160L,42161L,42162L,42163L,42164L,42165L,42166L,42167L,
42168L,42169L,42170L,42171L,42172L,42173L,42174L,42175L,42176L,42177L,
42178L,42179L,42180L,42181L,42182L,42183L,42184L,42185L,42186L,42187L,
42188L,42189L,42190L,42191L,42192L,42193L,42194L,42195L,42196L,42197L,
42198L,42199L,42200L,42201L,42202L,42203L,42204L,42205L,42206L,42207L,
42208L,42209L,42210L,42211L,42212L,42213L,42214L,42215L,42216L,42217L,
42218L,42219L,42220L,42221L,42222L,42223L,42224L,42225L,42226L,42227L,
42228L,42229L,42230L,42231L,42232L,42233L,42234L,42235L,42236L,42237L,
42238L,42239L,42240L,42241L,42242L,42243L,42244L,42245L,42246L,42247L,
42248L,42249L,42250L,42251L,42252L,42253L,42254L,42255L,42256L,42257L,
42258L,42259L,42260L,42261L,42262L,42263L,42264L,42265L,42266L,42267L,
42268L,42269L,42270L,42271L,42272L,42273L,42274L,42275L,42276L,42277L,
42278L,42279L,42280L,42281L,42282L,42283L,42284L,42285L,42286L,42287L,
42288L,42289L,42290L,42291L,42292L,42293L,42294L,42295L,42296L,42297L,
42298L,42299L,42300L,42301L,42302L,42303L,42304L,42305L,42306L,42307L,
42308L,42309L,42310L,42311L,42312L,42313L,42314L,42315L,42316L,42317L,
42318L,42319L,42320L,42321L,42322L,42323L,42324L,42325L,42326L,42327L,
42328L,42329L,42330L,42331L,42332L,42333L,42334L,42335L,42336L,42337L,
42338L,42339L,42340L,42341L,42342L,42343L,42344L,42345L,42346L,42347L,
42348L,42349L,42350L,42351L,42352L,42353L,42354L,42355L,42356L,42357L,
42358L,42359L,42360L,42361L,42362L,42363L,42364L,42365L,42366L,42367L,
42368L,42369L,42370L,42371L,42372L,42373L,42374L,42375L,42376L,42377L,
42378L,42379L,42380L,42381L,42382L,42383L,42384L,42385L,42386L,42387L,
42388L,42389L,42390L,42391L,42392L,42393L,42394L,42395L,42396L,42397L,
42398L,42399L,42400L,42401L,42402L,42403L,42404L,42405L,42406L,42407L,
42408L,42409L,42410L,42411L,42412L,42413L,42414L,42415L,42416L,42417L,
42418L,42419L,42420L,42421L,42422L,42423L,42424L,42425L,42426L,42427L,
42428L,42429L,42430L,42431L,42432L,42433L,42434L,42435L,42436L,42437L,
42438L,42439L,42440L,42441L,42442L,42443L,42444L,42445L,42446L,42447L,
42448L,42449L,42450L,42451L,42452L,42453L,42454L,42455L,42456L,42457L,
42458L,42459L,42460L,42461L,42462L,42463L,42464L,42465L,42466L,42467L,
42468L,42469L,42470L,42471L,42472L,42473L,42474L,42475L,42476L,42477L,
42478L,42479L,42480L,42481L,42482L,42483L,42484L,42485L,42486L,42487L,
42488L,42489L,42490L,42491L,42492L,42493L,42494L,42495L,42496L,42497L,
42498L,42499L,42500L,42501L,42502L,42503L,42504L,42505L,42506L,42507L,
42508L,42509L,42510L,42511L,42512L,42513L,42514L,42515L,42516L,42517L,
42518L,42519L,42520L,42521L,42522L,42523L,42524L,42525L,42526L,42527L,
42528L,42529L,42530L,42531L,42532L,42533L,42534L,42535L,42536L,42537L,
42538L,42539L,42540L,42541L,42542L,42543L,42544L,42545L,42546L,42547L,
42548L,42549L,42550L,42551L,42552L,42553L,42554L,42555L,42556L,42557L,
42558L,42559L,42560L,42560L,42562L,42562L,42564L,42564L,42566L,42566L,
42568L,42568L,42570L,42570L,42572L,42572L,42574L,42574L,42576L,42576L,
42578L,42578L,42580L,42580L,42582L,42582L,42584L,42584L,42586L,42586L,
42588L,42588L,42590L,42590L,42592L,42592L,42594L,42594L,42596L,42596L,
42598L,42598L,42600L,42600L,42602L,42602L,42604L,42604L,42606L,42607L,
42608L,42609L,42610L,42611L,42612L,42613L,42614L,42615L,42616L,42617L,
42618L,42619L,42620L,42621L,42622L,42623L,42624L,42624L,42626L,42626L,
42628L,42628L,42630L,42630L,42632L,42632L,42634L,42634L,42636L,42636L,
42638L,42638L,42640L,42640L,42642L,42642L,42644L,42644L,42646L,42646L,
42648L,42648L,42650L,42650L,42652L,42653L,42654L,42655L,42656L,42657L,
42658L,42659L,42660L,42661L,42662L,42663L,42664L,42665L,42666L,42667L,
42668L,42669L,42670L,42671L,42672L,42673L,42674L,42675L,42676L,42677L,
42678L,42679L,42680L,42681L,42682L,42683L,42684L,42685L,42686L,42687L,
42688L,42689L,42690L,42691L,42692L,42693L,42694L,42695L,42696L,42697L,
42698L,42699L,42700L,42701L,42702L,42703L,42704L,42705L,42706L,42707L,
42708L,42709L,42710L,42711L,42712L,42713L,42714L,42715L,42716L,42717L,
42718L,42719L,42720L,42721L,42722L,42723L,42724L,42725L,42726L,42727L,
42728L,42729L,42730L,42731L,42732L,42733L,42734L,42735L,42736L,42737L,
42738L,42739L,42740L,42741L,42742L,42743L,42744L,42745L,42746L,42747L,
42748L,42749L,42750L,42751L,42752L,42753L,42754L,42755L,42756L,42757L,
42758L,42759L,42760L,42761L,42762L,42763L,42764L,42765L,42766L,42767L,
42768L,42769L,42770L,42771L,42772L,42773L,42774L,42775L,42776L,42777L,
42778L,42779L,42780L,42781L,42782L,42783L,42784L,42785L,42786L,42786L,
42788L,42788L,42790L,42790L,42792L,42792L,42794L,42794L,42796L,42796L,
42798L,42798L,42800L,42801L,42802L,42802L,42804L,42804L,42806L,42806L,
42808L,42808L,42810L,42810L,42812L,42812L,42814L,42814L,42816L,42816L,
42818L,42818L,42820L,42820L,42822L,42822L,42824L,42824L,42826L,42826L,
42828L,42828L,42830L,42830L,42832L,42832L,42834L,42834L,42836L,42836L,
42838L,42838L,42840L,42840L,42842L,42842L,42844L,42844L,42846L,42846L,
42848L,42848L,42850L,42850L,42852L,42852L,42854L,42854L,42856L,42856L,
42858L,42858L,42860L,42860L,42862L,42862L,42864L,42865L,42866L,42867L,
42868L,42869L,42870L,42871L,42872L,42873L,42873L,42875L,42875L,42877L,
42878L,42878L,42880L,42880L,42882L,42882L,42884L,42884L,42886L,42886L,
42888L,42889L,42890L,42891L,42891L,42893L,42894L,42895L,42896L,42896L,
42898L,42898L,42948L,42901L,42902L,42902L,42904L,42904L,42906L,42906L,
42908L,42908L,42910L,42910L,42912L,42912L,42914L,42914L,42916L,42916L,
42918L,42918L,42920L,42920L,42922L,42923L,42924L,42925L,42926L,42927L,
42928L,42929L,42930L,42931L,42932L,42932L,42934L,42934L,42936L,42936L,
42938L,42938L,42940L,42940L,42942L,42942L,42944L,42945L,42946L,42946L,
42948L,42949L,42950L,42951L,42952L,42953L,42954L,42955L,42956L,42957L,
42958L,42959L,42960L,42961L,42962L,42963L,42964L,42965L,42966L,42967L,
42968L,42969L,42970L,42971L,42972L,42973L,42974L,42975L,42976L,42977L,
42978L,42979L,42980L,42981L,42982L,42983L,42984L,42985L,42986L,42987L,
42988L,42989L,42990L,42991L,42992L,42993L,42994L,42995L,42996L,42997L,
42998L,42999L,43000L,43001L,43002L,43003L,43004L,43005L,43006L,43007L,
43008L,43009L,43010L,43011L,43012L,43013L,43014L,43015L,43016L,43017L,
43018L,43019L,43020L,43021L,43022L,43023L,43024L,43025L,43026L,43027L,
43028L,43029L,43030L,43031L,43032L,43033L,43034L,43035L,43036L,43037L,
43038L,43039L,43040L,43041L,43042L,43043L,43044L,43045L,43046L,43047L,
43048L,43049L,43050L,43051L,43052L,43053L,43054L,43055L,43056L,43057L,
43058L,43059L,43060L,43061L,43062L,43063L,43064L,43065L,43066L,43067L,
43068L,43069L,43070L,43071L,43072L,43073L,43074L,43075L,43076L,43077L,
43078L,43079L,43080L,43081L,43082L,43083L,43084L,43085L,43086L,43087L,
43088L,43089L,43090L,43091L,43092L,43093L,43094L,43095L,43096L,43097L,
43098L,43099L,43100L,43101L,43102L,43103L,43104L,43105L,43106L,43107L,
43108L,43109L,43110L,43111L,43112L,43113L,43114L,43115L,43116L,43117L,
43118L,43119L,43120L,43121L,43122L,43123L,43124L,43125L,43126L,43127L,
43128L,43129L,43130L,43131L,43132L,43133L,43134L,43135L,43136L,43137L,
43138L,43139L,43140L,43141L,43142L,43143L,43144L,43145L,43146L,43147L,
43148L,43149L,43150L,43151L,43152L,43153L,43154L,43155L,43156L,43157L,
43158L,43159L,43160L,43161L,43162L,43163L,43164L,43165L,43166L,43167L,
43168L,43169L,43170L,43171L,43172L,43173L,43174L,43175L,43176L,43177L,
43178L,43179L,43180L,43181L,43182L,43183L,43184L,43185L,43186L,43187L,
43188L,43189L,43190L,43191L,43192L,43193L,43194L,43195L,43196L,43197L,
43198L,43199L,43200L,43201L,43202L,43203L,43204L,43205L,43206L,43207L,
43208L,43209L,43210L,43211L,43212L,43213L,43214L,43215L,43216L,43217L,
43218L,43219L,43220L,43221L,43222L,43223L,43224L,43225L,43226L,43227L,
43228L,43229L,43230L,43231L,43232L,43233L,43234L,43235L,43236L,43237L,
43238L,43239L,43240L,43241L,43242L,43243L,43244L,43245L,43246L,43247L,
43248L,43249L,43250L,43251L,43252L,43253L,43254L,43255L,43256L,43257L,
43258L,43259L,43260L,43261L,43262L,43263L,43264L,43265L,43266L,43267L,
43268L,43269L,43270L,43271L,43272L,43273L,43274L,43275L,43276L,43277L,
43278L,43279L,43280L,43281L,43282L,43283L,43284L,43285L,43286L,43287L,
43288L,43289L,43290L,43291L,43292L,43293L,43294L,43295L,43296L,43297L,
43298L,43299L,43300L,43301L,43302L,43303L,43304L,43305L,43306L,43307L,
43308L,43309L,43310L,43311L,43312L,43313L,43314L,43315L,43316L,43317L,
43318L,43319L,43320L,43321L,43322L,43323L,43324L,43325L,43326L,43327L,
43328L,43329L,43330L,43331L,43332L,43333L,43334L,43335L,43336L,43337L,
43338L,43339L,43340L,43341L,43342L,43343L,43344L,43345L,43346L,43347L,
43348L,43349L,43350L,43351L,43352L,43353L,43354L,43355L,43356L,43357L,
43358L,43359L,43360L,43361L,43362L,43363L,43364L,43365L,43366L,43367L,
43368L,43369L,43370L,43371L,43372L,43373L,43374L,43375L,43376L,43377L,
43378L,43379L,43380L,43381L,43382L,43383L,43384L,43385L,43386L,43387L,
43388L,43389L,43390L,43391L,43392L,43393L,43394L,43395L,43396L,43397L,
43398L,43399L,43400L,43401L,43402L,43403L,43404L,43405L,43406L,43407L,
43408L,43409L,43410L,43411L,43412L,43413L,43414L,43415L,43416L,43417L,
43418L,43419L,43420L,43421L,43422L,43423L,43424L,43425L,43426L,43427L,
43428L,43429L,43430L,43431L,43432L,43433L,43434L,43435L,43436L,43437L,
43438L,43439L,43440L,43441L,43442L,43443L,43444L,43445L,43446L,43447L,
43448L,43449L,43450L,43451L,43452L,43453L,43454L,43455L,43456L,43457L,
43458L,43459L,43460L,43461L,43462L,43463L,43464L,43465L,43466L,43467L,
43468L,43469L,43470L,43471L,43472L,43473L,43474L,43475L,43476L,43477L,
43478L,43479L,43480L,43481L,43482L,43483L,43484L,43485L,43486L,43487L,
43488L,43489L,43490L,43491L,43492L,43493L,43494L,43495L,43496L,43497L,
43498L,43499L,43500L,43501L,43502L,43503L,43504L,43505L,43506L,43507L,
43508L,43509L,43510L,43511L,43512L,43513L,43514L,43515L,43516L,43517L,
43518L,43519L,43520L,43521L,43522L,43523L,43524L,43525L,43526L,43527L,
43528L,43529L,43530L,43531L,43532L,43533L,43534L,43535L,43536L,43537L,
43538L,43539L,43540L,43541L,43542L,43543L,43544L,43545L,43546L,43547L,
43548L,43549L,43550L,43551L,43552L,43553L,43554L,43555L,43556L,43557L,
43558L,43559L,43560L,43561L,43562L,43563L,43564L,43565L,43566L,43567L,
43568L,43569L,43570L,43571L,43572L,43573L,43574L,43575L,43576L,43577L,
43578L,43579L,43580L,43581L,43582L,43583L,43584L,43585L,43586L,43587L,
43588L,43589L,43590L,43591L,43592L,43593L,43594L,43595L,43596L,43597L,
43598L,43599L,43600L,43601L,43602L,43603L,43604L,43605L,43606L,43607L,
43608L,43609L,43610L,43611L,43612L,43613L,43614L,43615L,43616L,43617L,
43618L,43619L,43620L,43621L,43622L,43623L,43624L,43625L,43626L,43627L,
43628L,43629L,43630L,43631L,43632L,43633L,43634L,43635L,43636L,43637L,
43638L,43639L,43640L,43641L,43642L,43643L,43644L,43645L,43646L,43647L,
43648L,43649L,43650L,43651L,43652L,43653L,43654L,43655L,43656L,43657L,
43658L,43659L,43660L,43661L,43662L,43663L,43664L,43665L,43666L,43667L,
43668L,43669L,43670L,43671L,43672L,43673L,43674L,43675L,43676L,43677L,
43678L,43679L,43680L,43681L,43682L,43683L,43684L,43685L,43686L,43687L,
43688L,43689L,43690L,43691L,43692L,43693L,43694L,43695L,43696L,43697L,
43698L,43699L,43700L,43701L,43702L,43703L,43704L,43705L,43706L,43707L,
43708L,43709L,43710L,43711L,43712L,43713L,43714L,43715L,43716L,43717L,
43718L,43719L,43720L,43721L,43722L,43723L,43724L,43725L,43726L,43727L,
43728L,43729L,43730L,43731L,43732L,43733L,43734L,43735L,43736L,43737L,
43738L,43739L,43740L,43741L,43742L,43743L,43744L,43745L,43746L,43747L,
43748L,43749L,43750L,43751L,43752L,43753L,43754L,43755L,43756L,43757L,
43758L,43759L,43760L,43761L,43762L,43763L,43764L,43765L,43766L,43767L,
43768L,43769L,43770L,43771L,43772L,43773L,43774L,43775L,43776L,43777L,
43778L,43779L,43780L,43781L,43782L,43783L,43784L,43785L,43786L,43787L,
43788L,43789L,43790L,43791L,43792L,43793L,43794L,43795L,43796L,43797L,
43798L,43799L,43800L,43801L,43802L,43803L,43804L,43805L,43806L,43807L,
43808L,43809L,43810L,43811L,43812L,43813L,43814L,43815L,43816L,43817L,
43818L,43819L,43820L,43821L,43822L,43823L,43824L,43825L,43826L,43827L,
43828L,43829L,43830L,43831L,43832L,43833L,43834L,43835L,43836L,43837L,
43838L,43839L,43840L,43841L,43842L,43843L,43844L,43845L,43846L,43847L,
43848L,43849L,43850L,43851L,43852L,43853L,43854L,43855L,43856L,43857L,
43858L,42931L,43860L,43861L,43862L,43863L,43864L,43865L,43866L,43867L,
43868L,43869L,43870L,43871L,43872L,43873L,43874L,43875L,43876L,43877L,
43878L,43879L,43880L,43881L,43882L,43883L,43884L,43885L,43886L,43887L,5024,
5025,5026,5027,5028,5029,5030,5031,5032,5033,5034,5035,5036,5037,5038,5039,
5040,5041,5042,5043,5044,5045,5046,5047,5048,5049,5050,5051,5052,5053,5054,
5055,5056,5057,5058,5059,5060,5061,5062,5063,5064,5065,5066,5067,5068,5069,
5070,5071,5072,5073,5074,5075,5076,5077,5078,5079,5080,5081,5082,5083,5084,
5085,5086,5087,5088,5089,5090,5091,5092,5093,5094,5095,5096,5097,5098,5099,
5100,5101,5102,5103,43968L,43969L,43970L,43971L,43972L,43973L,43974L,
43975L,43976L,43977L,43978L,43979L,43980L,43981L,43982L,43983L,43984L,
43985L,43986L,43987L,43988L,43989L,43990L,43991L,43992L,43993L,43994L,
43995L,43996L,43997L,43998L,43999L,44000L,44001L,44002L,44003L,44004L,
44005L,44006L,44007L,44008L,44009L,44010L,44011L,44012L,44013L,44014L,
44015L,44016L,44017L,44018L,44019L,44020L,44021L,44022L,44023L,44024L,
44025L,44026L,44027L,44028L,44029L,44030L,44031L,44032L,44033L,44034L,
44035L,44036L,44037L,44038L,44039L,44040L,44041L,44042L,44043L,44044L,
44045L,44046L,44047L,44048L,44049L,44050L,44051L,44052L,44053L,44054L,
44055L,44056L,44057L,44058L,44059L,44060L,44061L,44062L,44063L,44064L,
44065L,44066L,44067L,44068L,44069L,44070L,44071L,44072L,44073L,44074L,
44075L,44076L,44077L,44078L,44079L,44080L,44081L,44082L,44083L,44084L,
44085L,44086L,44087L,44088L,44089L,44090L,44091L,44092L,44093L,44094L,
44095L,44096L,44097L,44098L,44099L,44100L,44101L,44102L,44103L,44104L,
44105L,44106L,44107L,44108L,44109L,44110L,44111L,44112L,44113L,44114L,
44115L,44116L,44117L,44118L,44119L,44120L,44121L,44122L,44123L,44124L,
44125L,44126L,44127L,44128L,44129L,44130L,44131L,44132L,44133L,44134L,
44135L,44136L,44137L,44138L,44139L,44140L,44141L,44142L,44143L,44144L,
44145L,44146L,44147L,44148L,44149L,44150L,44151L,44152L,44153L,44154L,
44155L,44156L,44157L,44158L,44159L,44160L,44161L,44162L,44163L,44164L,
44165L,44166L,44167L,44168L,44169L,44170L,44171L,44172L,44173L,44174L,
44175L,44176L,44177L,44178L,44179L,44180L,44181L,44182L,44183L,44184L,
44185L,44186L,44187L,44188L,44189L,44190L,44191L,44192L,44193L,44194L,
44195L,44196L,44197L,44198L,44199L,44200L,44201L,44202L,44203L,44204L,
44205L,44206L,44207L,44208L,44209L,44210L,44211L,44212L,44213L,44214L,
44215L,44216L,44217L,44218L,44219L,44220L,44221L,44222L,44223L,44224L,
44225L,44226L,44227L,44228L,44229L,44230L,44231L,44232L,44233L,44234L,
44235L,44236L,44237L,44238L,44239L,44240L,44241L,44242L,44243L,44244L,
44245L,44246L,44247L,44248L,44249L,44250L,44251L,44252L,44253L,44254L,
44255L,44256L,44257L,44258L,44259L,44260L,44261L,44262L,44263L,44264L,
44265L,44266L,44267L,44268L,44269L,44270L,44271L,44272L,44273L,44274L,
44275L,44276L,44277L,44278L,44279L,44280L,44281L,44282L,44283L,44284L,
44285L,44286L,44287L,44288L,44289L,44290L,44291L,44292L,44293L,44294L,
44295L,44296L,44297L,44298L,44299L,44300L,44301L,44302L,44303L,44304L,
44305L,44306L,44307L,44308L,44309L,44310L,44311L,44312L,44313L,44314L,
44315L,44316L,44317L,44318L,44319L,44320L,44321L,44322L,44323L,44324L,
44325L,44326L,44327L,44328L,44329L,44330L,44331L,44332L,44333L,44334L,
44335L,44336L,44337L,44338L,44339L,44340L,44341L,44342L,44343L,44344L,
44345L,44346L,44347L,44348L,44349L,44350L,44351L,44352L,44353L,44354L,
44355L,44356L,44357L,44358L,44359L,44360L,44361L,44362L,44363L,44364L,
44365L,44366L,44367L,44368L,44369L,44370L,44371L,44372L,44373L,44374L,
44375L,44376L,44377L,44378L,44379L,44380L,44381L,44382L,44383L,44384L,
44385L,44386L,44387L,44388L,44389L,44390L,44391L,44392L,44393L,44394L,
44395L,44396L,44397L,44398L,44399L,44400L,44401L,44402L,44403L,44404L,
44405L,44406L,44407L,44408L,44409L,44410L,44411L,44412L,44413L,44414L,
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46025L,46026L,46027L,46028L,46029L,46030L,46031L,46032L,46033L,46034L,
46035L,46036L,46037L,46038L,46039L,46040L,46041L,46042L,46043L,46044L,
46045L,46046L,46047L,46048L,46049L,46050L,46051L,46052L,46053L,46054L,
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46065L,46066L,46067L,46068L,46069L,46070L,46071L,46072L,46073L,46074L,
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46085L,46086L,46087L,46088L,46089L,46090L,46091L,46092L,46093L,46094L,
46095L,46096L,46097L,46098L,46099L,46100L,46101L,46102L,46103L,46104L,
46105L,46106L,46107L,46108L,46109L,46110L,46111L,46112L,46113L,46114L,
46115L,46116L,46117L,46118L,46119L,46120L,46121L,46122L,46123L,46124L,
46125L,46126L,46127L,46128L,46129L,46130L,46131L,46132L,46133L,46134L,
46135L,46136L,46137L,46138L,46139L,46140L,46141L,46142L,46143L,46144L,
46145L,46146L,46147L,46148L,46149L,46150L,46151L,46152L,46153L,46154L,
46155L,46156L,46157L,46158L,46159L,46160L,46161L,46162L,46163L,46164L,
46165L,46166L,46167L,46168L,46169L,46170L,46171L,46172L,46173L,46174L,
46175L,46176L,46177L,46178L,46179L,46180L,46181L,46182L,46183L,46184L,
46185L,46186L,46187L,46188L,46189L,46190L,46191L,46192L,46193L,46194L,
46195L,46196L,46197L,46198L,46199L,46200L,46201L,46202L,46203L,46204L,
46205L,46206L,46207L,46208L,46209L,46210L,46211L,46212L,46213L,46214L,
46215L,46216L,46217L,46218L,46219L,46220L,46221L,46222L,46223L,46224L,
46225L,46226L,46227L,46228L,46229L,46230L,46231L,46232L,46233L,46234L,
46235L,46236L,46237L,46238L,46239L,46240L,46241L,46242L,46243L,46244L,
46245L,46246L,46247L,46248L,46249L,46250L,46251L,46252L,46253L,46254L,
46255L,46256L,46257L,46258L,46259L,46260L,46261L,46262L,46263L,46264L,
46265L,46266L,46267L,46268L,46269L,46270L,46271L,46272L,46273L,46274L,
46275L,46276L,46277L,46278L,46279L,46280L,46281L,46282L,46283L,46284L,
46285L,46286L,46287L,46288L,46289L,46290L,46291L,46292L,46293L,46294L,
46295L,46296L,46297L,46298L,46299L,46300L,46301L,46302L,46303L,46304L,
46305L,46306L,46307L,46308L,46309L,46310L,46311L,46312L,46313L,46314L,
46315L,46316L,46317L,46318L,46319L,46320L,46321L,46322L,46323L,46324L,
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48245L,48246L,48247L,48248L,48249L,48250L,48251L,48252L,48253L,48254L,
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51805L,51806L,51807L,51808L,51809L,51810L,51811L,51812L,51813L,51814L,
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51885L,51886L,51887L,51888L,51889L,51890L,51891L,51892L,51893L,51894L,
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51915L,51916L,51917L,51918L,51919L,51920L,51921L,51922L,51923L,51924L,
51925L,51926L,51927L,51928L,51929L,51930L,51931L,51932L,51933L,51934L,
51935L,51936L,51937L,51938L,51939L,51940L,51941L,51942L,51943L,51944L,
51945L,51946L,51947L,51948L,51949L,51950L,51951L,51952L,51953L,51954L,
51955L,51956L,51957L,51958L,51959L,51960L,51961L,51962L,51963L,51964L,
51965L,51966L,51967L,51968L,51969L,51970L,51971L,51972L,51973L,51974L,
51975L,51976L,51977L,51978L,51979L,51980L,51981L,51982L,51983L,51984L,
51985L,51986L,51987L,51988L,51989L,51990L,51991L,51992L,51993L,51994L,
51995L,51996L,51997L,51998L,51999L,52000L,52001L,52002L,52003L,52004L,
52005L,52006L,52007L,52008L,52009L,52010L,52011L,52012L,52013L,52014L,
52015L,52016L,52017L,52018L,52019L,52020L,52021L,52022L,52023L,52024L,
52025L,52026L,52027L,52028L,52029L,52030L,52031L,52032L,52033L,52034L,
52035L,52036L,52037L,52038L,52039L,52040L,52041L,52042L,52043L,52044L,
52045L,52046L,52047L,52048L,52049L,52050L,52051L,52052L,52053L,52054L,
52055L,52056L,52057L,52058L,52059L,52060L,52061L,52062L,52063L,52064L,
52065L,52066L,52067L,52068L,52069L,52070L,52071L,52072L,52073L,52074L,
52075L,52076L,52077L,52078L,52079L,52080L,52081L,52082L,52083L,52084L,
52085L,52086L,52087L,52088L,52089L,52090L,52091L,52092L,52093L,52094L,
52095L,52096L,52097L,52098L,52099L,52100L,52101L,52102L,52103L,52104L,
52105L,52106L,52107L,52108L,52109L,52110L,52111L,52112L,52113L,52114L,
52115L,52116L,52117L,52118L,52119L,52120L,52121L,52122L,52123L,52124L,
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52875L,52876L,52877L,52878L,52879L,52880L,52881L,52882L,52883L,52884L,
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52905L,52906L,52907L,52908L,52909L,52910L,52911L,52912L,52913L,52914L,
52915L,52916L,52917L,52918L,52919L,52920L,52921L,52922L,52923L,52924L,
52925L,52926L,52927L,52928L,52929L,52930L,52931L,52932L,52933L,52934L,
52935L,52936L,52937L,52938L,52939L,52940L,52941L,52942L,52943L,52944L,
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52955L,52956L,52957L,52958L,52959L,52960L,52961L,52962L,52963L,52964L,
52965L,52966L,52967L,52968L,52969L,52970L,52971L,52972L,52973L,52974L,
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53025L,53026L,53027L,53028L,53029L,53030L,53031L,53032L,53033L,53034L,
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53145L,53146L,53147L,53148L,53149L,53150L,53151L,53152L,53153L,53154L,
53155L,53156L,53157L,53158L,53159L,53160L,53161L,53162L,53163L,53164L,
53165L,53166L,53167L,53168L,53169L,53170L,53171L,53172L,53173L,53174L,
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53285L,53286L,53287L,53288L,53289L,53290L,53291L,53292L,53293L,53294L,
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53315L,53316L,53317L,53318L,53319L,53320L,53321L,53322L,53323L,53324L,
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53415L,53416L,53417L,53418L,53419L,53420L,53421L,53422L,53423L,53424L,
53425L,53426L,53427L,53428L,53429L,53430L,53431L,53432L,53433L,53434L,
53435L,53436L,53437L,53438L,53439L,53440L,53441L,53442L,53443L,53444L,
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53455L,53456L,53457L,53458L,53459L,53460L,53461L,53462L,53463L,53464L,
53465L,53466L,53467L,53468L,53469L,53470L,53471L,53472L,53473L,53474L,
53475L,53476L,53477L,53478L,53479L,53480L,53481L,53482L,53483L,53484L,
53485L,53486L,53487L,53488L,53489L,53490L,53491L,53492L,53493L,53494L,
53495L,53496L,53497L,53498L,53499L,53500L,53501L,53502L,53503L,53504L,
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53515L,53516L,53517L,53518L,53519L,53520L,53521L,53522L,53523L,53524L,
53525L,53526L,53527L,53528L,53529L,53530L,53531L,53532L,53533L,53534L,
53535L,53536L,53537L,53538L,53539L,53540L,53541L,53542L,53543L,53544L,
53545L,53546L,53547L,53548L,53549L,53550L,53551L,53552L,53553L,53554L,
53555L,53556L,53557L,53558L,53559L,53560L,53561L,53562L,53563L,53564L,
53565L,53566L,53567L,53568L,53569L,53570L,53571L,53572L,53573L,53574L,
53575L,53576L,53577L,53578L,53579L,53580L,53581L,53582L,53583L,53584L,
53585L,53586L,53587L,53588L,53589L,53590L,53591L,53592L,53593L,53594L,
53595L,53596L,53597L,53598L,53599L,53600L,53601L,53602L,53603L,53604L,
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53615L,53616L,53617L,53618L,53619L,53620L,53621L,53622L,53623L,53624L,
53625L,53626L,53627L,53628L,53629L,53630L,53631L,53632L,53633L,53634L,
53635L,53636L,53637L,53638L,53639L,53640L,53641L,53642L,53643L,53644L,
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53655L,53656L,53657L,53658L,53659L,53660L,53661L,53662L,53663L,53664L,
53665L,53666L,53667L,53668L,53669L,53670L,53671L,53672L,53673L,53674L,
53675L,53676L,53677L,53678L,53679L,53680L,53681L,53682L,53683L,53684L,
53685L,53686L,53687L,53688L,53689L,53690L,53691L,53692L,53693L,53694L,
53695L,53696L,53697L,53698L,53699L,53700L,53701L,53702L,53703L,53704L,
53705L,53706L,53707L,53708L,53709L,53710L,53711L,53712L,53713L,53714L,
53715L,53716L,53717L,53718L,53719L,53720L,53721L,53722L,53723L,53724L,
53725L,53726L,53727L,53728L,53729L,53730L,53731L,53732L,53733L,53734L,
53735L,53736L,53737L,53738L,53739L,53740L,53741L,53742L,53743L,53744L,
53745L,53746L,53747L,53748L,53749L,53750L,53751L,53752L,53753L,53754L,
53755L,53756L,53757L,53758L,53759L,53760L,53761L,53762L,53763L,53764L,
53765L,53766L,53767L,53768L,53769L,53770L,53771L,53772L,53773L,53774L,
53775L,53776L,53777L,53778L,53779L,53780L,53781L,53782L,53783L,53784L,
53785L,53786L,53787L,53788L,53789L,53790L,53791L,53792L,53793L,53794L,
53795L,53796L,53797L,53798L,53799L,53800L,53801L,53802L,53803L,53804L,
53805L,53806L,53807L,53808L,53809L,53810L,53811L,53812L,53813L,53814L,
53815L,53816L,53817L,53818L,53819L,53820L,53821L,53822L,53823L,53824L,
53825L,53826L,53827L,53828L,53829L,53830L,53831L,53832L,53833L,53834L,
53835L,53836L,53837L,53838L,53839L,53840L,53841L,53842L,53843L,53844L,
53845L,53846L,53847L,53848L,53849L,53850L,53851L,53852L,53853L,53854L,
53855L,53856L,53857L,53858L,53859L,53860L,53861L,53862L,53863L,53864L,
53865L,53866L,53867L,53868L,53869L,53870L,53871L,53872L,53873L,53874L,
53875L,53876L,53877L,53878L,53879L,53880L,53881L,53882L,53883L,53884L,
53885L,53886L,53887L,53888L,53889L,53890L,53891L,53892L,53893L,53894L,
53895L,53896L,53897L,53898L,53899L,53900L,53901L,53902L,53903L,53904L,
53905L,53906L,53907L,53908L,53909L,53910L,53911L,53912L,53913L,53914L,
53915L,53916L,53917L,53918L,53919L,53920L,53921L,53922L,53923L,53924L,
53925L,53926L,53927L,53928L,53929L,53930L,53931L,53932L,53933L,53934L,
53935L,53936L,53937L,53938L,53939L,53940L,53941L,53942L,53943L,53944L,
53945L,53946L,53947L,53948L,53949L,53950L,53951L,53952L,53953L,53954L,
53955L,53956L,53957L,53958L,53959L,53960L,53961L,53962L,53963L,53964L,
53965L,53966L,53967L,53968L,53969L,53970L,53971L,53972L,53973L,53974L,
53975L,53976L,53977L,53978L,53979L,53980L,53981L,53982L,53983L,53984L,
53985L,53986L,53987L,53988L,53989L,53990L,53991L,53992L,53993L,53994L,
53995L,53996L,53997L,53998L,53999L,54000L,54001L,54002L,54003L,54004L,
54005L,54006L,54007L,54008L,54009L,54010L,54011L,54012L,54013L,54014L,
54015L,54016L,54017L,54018L,54019L,54020L,54021L,54022L,54023L,54024L,
54025L,54026L,54027L,54028L,54029L,54030L,54031L,54032L,54033L,54034L,
54035L,54036L,54037L,54038L,54039L,54040L,54041L,54042L,54043L,54044L,
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55765L,55766L,55767L,55768L,55769L,55770L,55771L,55772L,55773L,55774L,
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55815L,55816L,55817L,55818L,55819L,55820L,55821L,55822L,55823L,55824L,
55825L,55826L,55827L,55828L,55829L,55830L,55831L,55832L,55833L,55834L,
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55845L,55846L,55847L,55848L,55849L,55850L,55851L,55852L,55853L,55854L,
55855L,55856L,55857L,55858L,55859L,55860L,55861L,55862L,55863L,55864L,
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55885L,55886L,55887L,55888L,55889L,55890L,55891L,55892L,55893L,55894L,
55895L,55896L,55897L,55898L,55899L,55900L,55901L,55902L,55903L,55904L,
55905L,55906L,55907L,55908L,55909L,55910L,55911L,55912L,55913L,55914L,
55915L,55916L,55917L,55918L,55919L,55920L,55921L,55922L,55923L,55924L,
55925L,55926L,55927L,55928L,55929L,55930L,55931L,55932L,55933L,55934L,
55935L,55936L,55937L,55938L,55939L,55940L,55941L,55942L,55943L,55944L,
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59595L,59596L,59597L,59598L,59599L,59600L,59601L,59602L,59603L,59604L,
59605L,59606L,59607L,59608L,59609L,59610L,59611L,59612L,59613L,59614L,
59615L,59616L,59617L,59618L,59619L,59620L,59621L,59622L,59623L,59624L,
59625L,59626L,59627L,59628L,59629L,59630L,59631L,59632L,59633L,59634L,
59635L,59636L,59637L,59638L,59639L,59640L,59641L,59642L,59643L,59644L,
59645L,59646L,59647L,59648L,59649L,59650L,59651L,59652L,59653L,59654L,
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59665L,59666L,59667L,59668L,59669L,59670L,59671L,59672L,59673L,59674L,
59675L,59676L,59677L,59678L,59679L,59680L,59681L,59682L,59683L,59684L,
59685L,59686L,59687L,59688L,59689L,59690L,59691L,59692L,59693L,59694L,
59695L,59696L,59697L,59698L,59699L,59700L,59701L,59702L,59703L,59704L,
59705L,59706L,59707L,59708L,59709L,59710L,59711L,59712L,59713L,59714L,
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63345L,63346L,63347L,63348L,63349L,63350L,63351L,63352L,63353L,63354L,
63355L,63356L,63357L,63358L,63359L,63360L,63361L,63362L,63363L,63364L,
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63395L,63396L,63397L,63398L,63399L,63400L,63401L,63402L,63403L,63404L,
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63415L,63416L,63417L,63418L,63419L,63420L,63421L,63422L,63423L,63424L,
63425L,63426L,63427L,63428L,63429L,63430L,63431L,63432L,63433L,63434L,
63435L,63436L,63437L,63438L,63439L,63440L,63441L,63442L,63443L,63444L,
63445L,63446L,63447L,63448L,63449L,63450L,63451L,63452L,63453L,63454L,
63455L,63456L,63457L,63458L,63459L,63460L,63461L,63462L,63463L,63464L,
63465L,63466L,63467L,63468L,63469L,63470L,63471L,63472L,63473L,63474L,
63475L,63476L,63477L,63478L,63479L,63480L,63481L,63482L,63483L,63484L,
63485L,63486L,63487L,63488L,63489L,63490L,63491L,63492L,63493L,63494L,
63495L,63496L,63497L,63498L,63499L,63500L,63501L,63502L,63503L,63504L,
63505L,63506L,63507L,63508L,63509L,63510L,63511L,63512L,63513L,63514L,
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65445L,65446L,65447L,65448L,65449L,65450L,65451L,65452L,65453L,65454L,
65455L,65456L,65457L,65458L,65459L,65460L,65461L,65462L,65463L,65464L,
65465L,65466L,65467L,65468L,65469L,65470L,65471L,65472L,65473L,65474L,
65475L,65476L,65477L,65478L,65479L,65480L,65481L,65482L,65483L,65484L,
65485L,65486L,65487L,65488L,65489L,65490L,65491L,65492L,65493L,65494L,
65495L,65496L,65497L,65498L,65499L,65500L,65501L,65502L,65503L,65504L,
65505L,65506L,65507L,65508L,65509L,65510L,65511L,65512L,65513L,65514L,
65515L,65516L,65517L,65518L,65519L,65520L,65521L,65522L,65523L,65524L,
65525L,65526L,65527L,65528L,65529L,65530L,65531L,65532L,65533L,65534L,
65535L,
};
#endif

#if defined(DUK_USE_REGEXP_CANON_BITMAP)
/*
 *  Automatically generated by extract_caseconv.py, do not edit!
 */

const duk_uint8_t duk_unicode_re_canon_bitmap[256] = {
23,0,224,19,1,228,255,255,255,255,255,255,255,255,255,255,63,254,255,127,
255,255,255,255,255,255,255,255,231,231,0,16,255,227,255,255,63,255,255,
255,255,255,255,255,1,252,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
227,129,255,255,255,147,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,251,
};
#endif
/*
 *  Bitstream decoder.
 */

/* #include duk_internal.h -> already included */

/* Decode 'bits' bits from the input stream (bits must be 1...24).
 * When reading past bitstream end, zeroes are shifted in.  The result
 * is signed to match duk_bd_decode_flagged.
 */
DUK_INTERNAL duk_uint32_t duk_bd_decode(duk_bitdecoder_ctx *ctx, duk_small_int_t bits) {
	duk_small_int_t shift;
	duk_uint32_t mask;
	duk_uint32_t tmp;

	/* Note: cannot read more than 24 bits without possibly shifting top bits out.
	 * Fixable, but adds complexity.
	 */
	DUK_ASSERT(bits >= 1 && bits <= 24);

	while (ctx->currbits < bits) {
#if 0
		DUK_DDD(DUK_DDDPRINT("decode_bits: shift more data (bits=%ld, currbits=%ld)",
		                     (long) bits, (long) ctx->currbits));
#endif
		ctx->currval <<= 8;
		if (ctx->offset < ctx->length) {
			/* If ctx->offset >= ctx->length, we "shift zeroes in"
			 * instead of croaking.
			 */
			ctx->currval |= ctx->data[ctx->offset++];
		}
		ctx->currbits += 8;
	}
#if 0
	DUK_DDD(DUK_DDDPRINT("decode_bits: bits=%ld, currbits=%ld, currval=0x%08lx",
	                     (long) bits, (long) ctx->currbits, (unsigned long) ctx->currval));
#endif

	/* Extract 'top' bits of currval; note that the extracted bits do not need
	 * to be cleared, we just ignore them on next round.
	 */
	shift = ctx->currbits - bits;
	mask = (((duk_uint32_t) 1U) << bits) - 1U;
	tmp = (ctx->currval >> shift) & mask;
	ctx->currbits = shift;  /* remaining */

#if 0
	DUK_DDD(DUK_DDDPRINT("decode_bits: %ld bits -> 0x%08lx (%ld), currbits=%ld, currval=0x%08lx",
	                     (long) bits, (unsigned long) tmp, (long) tmp, (long) ctx->currbits, (unsigned long) ctx->currval));
#endif

	return tmp;
}

DUK_INTERNAL duk_small_uint_t duk_bd_decode_flag(duk_bitdecoder_ctx *ctx) {
	return (duk_small_uint_t) duk_bd_decode(ctx, 1);
}

/* Decode a one-bit flag, and if set, decode a value of 'bits', otherwise return
 * default value.
 */
DUK_INTERNAL duk_uint32_t duk_bd_decode_flagged(duk_bitdecoder_ctx *ctx, duk_small_int_t bits, duk_uint32_t def_value) {
	if (duk_bd_decode_flag(ctx)) {
		return duk_bd_decode(ctx, bits);
	} else {
		return def_value;
	}
}

/* Signed variant, allows negative marker value. */
DUK_INTERNAL duk_int32_t duk_bd_decode_flagged_signed(duk_bitdecoder_ctx *ctx, duk_small_int_t bits, duk_int32_t def_value) {
	return (duk_int32_t) duk_bd_decode_flagged(ctx, bits, (duk_uint32_t) def_value);
}

/* Shared varint encoding.  Match dukutil.py BitEncode.varuint(). */
DUK_INTERNAL duk_uint32_t duk_bd_decode_varuint(duk_bitdecoder_ctx *ctx) {
	duk_small_uint_t t;

	/* The bit encoding choices here are based on manual testing against
	 * the actual varuints generated by genbuiltins.py.
	 */
	switch (duk_bd_decode(ctx, 2)) {
	case 0:
		return 0;  /* [0,0] */
	case 1:
		return duk_bd_decode(ctx, 2) + 1;  /* [1,4] */
	case 2:
		return duk_bd_decode(ctx, 5) + 5;  /* [5,36] */
	default:
		t = duk_bd_decode(ctx, 7);
		if (t == 0) {
			return duk_bd_decode(ctx, 20);
		}
		return (t - 1) + 37;  /* [37,163] */
	}
}

/* Decode a bit packed string from a custom format used by genbuiltins.py.
 * This function is here because it's used for both heap and thread inits.
 * Caller must supply the output buffer whose size is NOT checked!
 */

#define DUK__BITPACK_LETTER_LIMIT  26
#define DUK__BITPACK_LOOKUP1       26
#define DUK__BITPACK_LOOKUP2       27
#define DUK__BITPACK_SWITCH1       28
#define DUK__BITPACK_SWITCH        29
#define DUK__BITPACK_UNUSED1       30
#define DUK__BITPACK_EIGHTBIT      31

DUK_LOCAL const duk_uint8_t duk__bitpacked_lookup[16] = {
	DUK_ASC_0, DUK_ASC_1, DUK_ASC_2, DUK_ASC_3,
	DUK_ASC_4, DUK_ASC_5, DUK_ASC_6, DUK_ASC_7,
	DUK_ASC_8, DUK_ASC_9, DUK_ASC_UNDERSCORE, DUK_ASC_SPACE,
	0x82, 0x80, DUK_ASC_DOUBLEQUOTE, DUK_ASC_LCURLY
};

DUK_INTERNAL duk_small_uint_t duk_bd_decode_bitpacked_string(duk_bitdecoder_ctx *bd, duk_uint8_t *out) {
	duk_small_uint_t len;
	duk_small_uint_t mode;
	duk_small_uint_t t;
	duk_small_uint_t i;

	len = duk_bd_decode(bd, 5);
	if (len == 31) {
		len = duk_bd_decode(bd, 8);  /* Support up to 256 bytes; rare. */
	}

	mode = 32;  /* 0 = uppercase, 32 = lowercase (= 'a' - 'A') */
	for (i = 0; i < len; i++) {
		t = duk_bd_decode(bd, 5);
		if (t < DUK__BITPACK_LETTER_LIMIT) {
			t = t + DUK_ASC_UC_A + mode;
		} else if (t == DUK__BITPACK_LOOKUP1) {
			t = duk__bitpacked_lookup[duk_bd_decode(bd, 3)];
		} else if (t == DUK__BITPACK_LOOKUP2) {
			t = duk__bitpacked_lookup[8 + duk_bd_decode(bd, 3)];
		} else if (t == DUK__BITPACK_SWITCH1) {
			t = duk_bd_decode(bd, 5);
			DUK_ASSERT_DISABLE(t >= 0);  /* unsigned */
			DUK_ASSERT(t <= 25);
			t = t + DUK_ASC_UC_A + (mode ^ 32);
		} else if (t == DUK__BITPACK_SWITCH) {
			mode = mode ^ 32;
			t = duk_bd_decode(bd, 5);
			DUK_ASSERT_DISABLE(t >= 0);
			DUK_ASSERT(t <= 25);
			t = t + DUK_ASC_UC_A + mode;
		} else if (t == DUK__BITPACK_EIGHTBIT) {
			t = duk_bd_decode(bd, 8);
		}
		out[i] = (duk_uint8_t) t;
	}

	return len;
}

/* automatic undefs */
#undef DUK__BITPACK_EIGHTBIT
#undef DUK__BITPACK_LETTER_LIMIT
#undef DUK__BITPACK_LOOKUP1
#undef DUK__BITPACK_LOOKUP2
#undef DUK__BITPACK_SWITCH
#undef DUK__BITPACK_SWITCH1
#undef DUK__BITPACK_UNUSED1
/*
 *  Bitstream encoder.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL void duk_be_encode(duk_bitencoder_ctx *ctx, duk_uint32_t data, duk_small_int_t bits) {
	duk_uint8_t tmp;

	DUK_ASSERT(ctx != NULL);
	DUK_ASSERT(ctx->currbits < 8);

	/* This limitation would be fixable but adds unnecessary complexity. */
	DUK_ASSERT(bits >= 1 && bits <= 24);

	ctx->currval = (ctx->currval << bits) | data;
	ctx->currbits += bits;

	while (ctx->currbits >= 8) {
		if (ctx->offset < ctx->length) {
			tmp = (duk_uint8_t) ((ctx->currval >> (ctx->currbits - 8)) & 0xff);
			ctx->data[ctx->offset++] = tmp;
		} else {
			/* If buffer has been exhausted, truncate bitstream */
			ctx->truncated = 1;
		}

		ctx->currbits -= 8;
	}
}

DUK_INTERNAL void duk_be_finish(duk_bitencoder_ctx *ctx) {
	duk_small_int_t npad;

	DUK_ASSERT(ctx != NULL);
	DUK_ASSERT(ctx->currbits < 8);

	npad = (duk_small_int_t) (8 - ctx->currbits);
	if (npad > 0) {
		duk_be_encode(ctx, 0, npad);
	}
	DUK_ASSERT(ctx->currbits == 0);
}
/*
 *  Fast buffer writer with slack management.
 */

/* #include duk_internal.h -> already included */

/* XXX: Avoid duk_{memcmp,memmove}_unsafe() by imposing a minimum length of
 * >0 for the underlying dynamic buffer.
 */

/*
 *  Macro support functions (use only macros in calling code)
 */

DUK_LOCAL void duk__bw_update_ptrs(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_size_t curr_offset, duk_size_t new_length) {
	duk_uint8_t *p;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw_ctx != NULL);
	DUK_UNREF(thr);

	/* 'p' might be NULL when the underlying buffer is zero size.  If so,
	 * the resulting pointers are not used unsafely.
	 */
	p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, bw_ctx->buf);
	DUK_ASSERT(p != NULL || (DUK_HBUFFER_DYNAMIC_GET_SIZE(bw_ctx->buf) == 0 && curr_offset == 0 && new_length == 0));
	bw_ctx->p = p + curr_offset;
	bw_ctx->p_base = p;
	bw_ctx->p_limit = p + new_length;
}

DUK_INTERNAL void duk_bw_init(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_hbuffer_dynamic *h_buf) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw_ctx != NULL);
	DUK_ASSERT(h_buf != NULL);

	bw_ctx->buf = h_buf;
	duk__bw_update_ptrs(thr, bw_ctx, 0, DUK_HBUFFER_DYNAMIC_GET_SIZE(h_buf));
}

DUK_INTERNAL void duk_bw_init_pushbuf(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_size_t buf_size) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw_ctx != NULL);

	(void) duk_push_dynamic_buffer(thr, buf_size);
	bw_ctx->buf = (duk_hbuffer_dynamic *) duk_known_hbuffer(thr, -1);
	DUK_ASSERT(bw_ctx->buf != NULL);
	duk__bw_update_ptrs(thr, bw_ctx, 0, buf_size);
}

/* Resize target buffer for requested size.  Called by the macro only when the
 * fast path test (= there is space) fails.
 */
DUK_INTERNAL duk_uint8_t *duk_bw_resize(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx, duk_size_t sz) {
	duk_size_t curr_off;
	duk_size_t add_sz;
	duk_size_t new_sz;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw_ctx != NULL);

	/* We could do this operation without caller updating bw_ctx->ptr,
	 * but by writing it back here we can share code better.
	 */

	curr_off = (duk_size_t) (bw_ctx->p - bw_ctx->p_base);
	add_sz = (curr_off >> DUK_BW_SLACK_SHIFT) + DUK_BW_SLACK_ADD;
	new_sz = curr_off + sz + add_sz;
	if (DUK_UNLIKELY(new_sz < curr_off)) {
		/* overflow */
		DUK_ERROR_RANGE(thr, DUK_STR_BUFFER_TOO_LONG);
		DUK_WO_NORETURN(return NULL;);
	}
#if 0  /* for manual torture testing: tight allocation, useful with valgrind */
	new_sz = curr_off + sz;
#endif

	/* This is important to ensure dynamic buffer data pointer is not
	 * NULL (which is possible if buffer size is zero), which in turn
	 * causes portability issues with e.g. memmove() and memcpy().
	 */
	DUK_ASSERT(new_sz >= 1);

	DUK_DD(DUK_DDPRINT("resize bufferwriter from %ld to %ld (add_sz=%ld)", (long) curr_off, (long) new_sz, (long) add_sz));

	duk_hbuffer_resize(thr, bw_ctx->buf, new_sz);
	duk__bw_update_ptrs(thr, bw_ctx, curr_off, new_sz);
	return bw_ctx->p;
}

/* Make buffer compact, matching current written size. */
DUK_INTERNAL void duk_bw_compact(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx) {
	duk_size_t len;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw_ctx != NULL);
	DUK_UNREF(thr);

	len = (duk_size_t) (bw_ctx->p - bw_ctx->p_base);
	duk_hbuffer_resize(thr, bw_ctx->buf, len);
	duk__bw_update_ptrs(thr, bw_ctx, len, len);
}

DUK_INTERNAL void duk_bw_write_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t src_off, duk_size_t len) {
	duk_uint8_t *p_base;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(src_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off + len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_UNREF(thr);

	p_base = bw->p_base;
	duk_memcpy_unsafe((void *) bw->p,
	                  (const void *) (p_base + src_off),
	                  (size_t) len);
	bw->p += len;
}

DUK_INTERNAL void duk_bw_write_ensure_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t src_off, duk_size_t len) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(src_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off + len <= DUK_BW_GET_SIZE(thr, bw));

	DUK_BW_ENSURE(thr, bw, len);
	duk_bw_write_raw_slice(thr, bw, src_off, len);
}

DUK_INTERNAL void duk_bw_insert_raw_bytes(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, const duk_uint8_t *buf, duk_size_t len) {
	duk_uint8_t *p_base;
	duk_size_t buf_sz, move_sz;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(dst_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(buf != NULL);
	DUK_UNREF(thr);

	p_base = bw->p_base;
	buf_sz = (duk_size_t) (bw->p - p_base);  /* constrained by maximum buffer size */
	move_sz = buf_sz - dst_off;

	DUK_ASSERT(p_base != NULL);  /* buffer size is >= 1 */
	duk_memmove_unsafe((void *) (p_base + dst_off + len),
	                   (const void *) (p_base + dst_off),
	                   (size_t) move_sz);
	duk_memcpy_unsafe((void *) (p_base + dst_off),
	                  (const void *) buf,
	                  (size_t) len);
	bw->p += len;
}

DUK_INTERNAL void duk_bw_insert_ensure_bytes(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, const duk_uint8_t *buf, duk_size_t len) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(dst_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(buf != NULL);

	DUK_BW_ENSURE(thr, bw, len);
	duk_bw_insert_raw_bytes(thr, bw, dst_off, buf, len);
}

DUK_INTERNAL void duk_bw_insert_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, duk_size_t src_off, duk_size_t len) {
	duk_uint8_t *p_base;
	duk_size_t buf_sz, move_sz;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(dst_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off + len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_UNREF(thr);

	p_base = bw->p_base;

	/* Don't support "straddled" source now. */
	DUK_ASSERT(dst_off <= src_off || dst_off >= src_off + len);

	if (dst_off <= src_off) {
		/* Target is before source.  Source offset is expressed as
		 * a "before change" offset.  Account for the memmove.
		 */
		src_off += len;
	}

	buf_sz = (duk_size_t) (bw->p - p_base);
	move_sz = buf_sz - dst_off;

	DUK_ASSERT(p_base != NULL);  /* buffer size is >= 1 */
	duk_memmove_unsafe((void *) (p_base + dst_off + len),
	                   (const void *) (p_base + dst_off),
	                   (size_t) move_sz);
	duk_memcpy_unsafe((void *) (p_base + dst_off),
	                  (const void *) (p_base + src_off),
	                  (size_t) len);
	bw->p += len;
}

DUK_INTERNAL void duk_bw_insert_ensure_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t dst_off, duk_size_t src_off, duk_size_t len) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(dst_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(src_off + len <= DUK_BW_GET_SIZE(thr, bw));

	/* Don't support "straddled" source now. */
	DUK_ASSERT(dst_off <= src_off || dst_off >= src_off + len);

	DUK_BW_ENSURE(thr, bw, len);
	duk_bw_insert_raw_slice(thr, bw, dst_off, src_off, len);
}

DUK_INTERNAL duk_uint8_t *duk_bw_insert_raw_area(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len) {
	duk_uint8_t *p_base, *p_dst, *p_src;
	duk_size_t buf_sz, move_sz;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_UNREF(thr);

	p_base = bw->p_base;
	buf_sz = (duk_size_t) (bw->p - p_base);
	move_sz = buf_sz - off;
	p_dst = p_base + off + len;
	p_src = p_base + off;
	duk_memmove_unsafe((void *) p_dst, (const void *) p_src, (size_t) move_sz);
	return p_src;  /* point to start of 'reserved area' */
}

DUK_INTERNAL duk_uint8_t *duk_bw_insert_ensure_area(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(off <= DUK_BW_GET_SIZE(thr, bw));

	DUK_BW_ENSURE(thr, bw, len);
	return duk_bw_insert_raw_area(thr, bw, off, len);
}

DUK_INTERNAL void duk_bw_remove_raw_slice(duk_hthread *thr, duk_bufwriter_ctx *bw, duk_size_t off, duk_size_t len) {
	duk_size_t move_sz;

	duk_uint8_t *p_base;
	duk_uint8_t *p_src;
	duk_uint8_t *p_dst;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(bw != NULL);
	DUK_ASSERT(off <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_ASSERT(off + len <= DUK_BW_GET_SIZE(thr, bw));
	DUK_UNREF(thr);

	p_base = bw->p_base;
	p_dst = p_base + off;
	p_src = p_dst + len;
	move_sz = (duk_size_t) (bw->p - p_src);
	duk_memmove_unsafe((void *) p_dst,
	                   (const void *) p_src,
	                   (size_t) move_sz);
	bw->p -= len;
}

/*
 *  Assertion helpers
 */

#if defined(DUK_USE_ASSERTIONS)
DUK_INTERNAL void duk_bw_assert_valid(duk_hthread *thr, duk_bufwriter_ctx *bw_ctx) {
	DUK_UNREF(thr);
	DUK_ASSERT(bw_ctx != NULL);
	DUK_ASSERT(bw_ctx->buf != NULL);
	DUK_ASSERT((DUK_HBUFFER_DYNAMIC_GET_SIZE(bw_ctx->buf) == 0) ||
	           (bw_ctx->p != NULL &&
	            bw_ctx->p_base != NULL &&
	            bw_ctx->p_limit != NULL &&
	            bw_ctx->p_limit >= bw_ctx->p_base &&
	            bw_ctx->p >= bw_ctx->p_base &&
	            bw_ctx->p <= bw_ctx->p_limit));
}
#endif
/*
 *  Cast helpers.
 *
 *  C99+ coercion is challenging portability-wise because out-of-range casts
 *  may invoke implementation defined or even undefined behavior.  See e.g.
 *  http://blog.frama-c.com/index.php?post/2013/10/09/Overflow-float-integer.
 *
 *  Provide explicit cast helpers which try to avoid implementation defined
 *  or undefined behavior.  These helpers can then be simplified in the vast
 *  majority of cases where the implementation defined or undefined behavior
 *  is not problematic.
 */

/* #include duk_internal.h -> already included */

/* Portable double-to-integer cast which avoids undefined behavior and avoids
 * relying on fmin(), fmax(), or other intrinsics.  Out-of-range results are
 * not assumed by caller, but here value is clamped, NaN converts to minval.
 */
#define DUK__DOUBLE_INT_CAST1(tname,minval,maxval)  do { \
		if (DUK_LIKELY(x >= (duk_double_t) (minval))) { \
			DUK_ASSERT(!DUK_ISNAN(x)); \
			if (DUK_LIKELY(x <= (duk_double_t) (maxval))) { \
				return (tname) x; \
			} else { \
				return (tname) (maxval); \
			} \
		} else { \
			/* NaN or below minval.  Since we don't care about the result \
			 * for out-of-range values, just return the minimum value for \
			 * both. \
			 */ \
			return (tname) (minval); \
		} \
	} while (0)

/* Rely on specific NaN behavior for duk_double_{fmin,fmax}(): if either
 * argument is a NaN, return the second argument.  This avoids a
 * NaN-to-integer cast which is undefined behavior.
 */
#define DUK__DOUBLE_INT_CAST2(tname,minval,maxval)  do { \
		return (tname) duk_double_fmin(duk_double_fmax(x, (duk_double_t) (minval)), (duk_double_t) (maxval)); \
	} while (0)

/* Another solution which doesn't need C99+ behavior for fmin() and fmax(). */
#define DUK__DOUBLE_INT_CAST3(tname,minval,maxval)  do { \
		if (DUK_ISNAN(x)) { \
			/* 0 or any other value is fine. */ \
			return (tname) 0; \
		} else \
			return (tname) DUK_FMIN(DUK_FMAX(x, (duk_double_t) (minval)), (duk_double_t) (maxval)); \
		} \
	} while (0)

/* C99+ solution: relies on specific fmin() and fmax() behavior in C99: if
 * one argument is NaN but the other isn't, the non-NaN argument is returned.
 * Because the limits are non-NaN values, explicit NaN check is not needed.
 * This may not work on all legacy platforms, and also doesn't seem to inline
 * the fmin() and fmax() calls (unless one uses -ffast-math which we don't
 * support).
 */
#define DUK__DOUBLE_INT_CAST4(tname,minval,maxval)  do { \
		return (tname) DUK_FMIN(DUK_FMAX(x, (duk_double_t) (minval)), (duk_double_t) (maxval)); \
	} while (0)

DUK_INTERNAL duk_int_t duk_double_to_int_t(duk_double_t x) {
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	/* Real world solution: almost any practical platform will provide
	 * an integer value without any guarantees what it is (which is fine).
	 */
	return (duk_int_t) x;
#else
	DUK__DOUBLE_INT_CAST1(duk_int_t, DUK_INT_MIN, DUK_INT_MAX);
#endif
}

DUK_INTERNAL duk_uint_t duk_double_to_uint_t(duk_double_t x) {
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	return (duk_uint_t) x;
#else
	DUK__DOUBLE_INT_CAST1(duk_uint_t, DUK_UINT_MIN, DUK_UINT_MAX);
#endif
}

DUK_INTERNAL duk_int32_t duk_double_to_int32_t(duk_double_t x) {
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	return (duk_int32_t) x;
#else
	DUK__DOUBLE_INT_CAST1(duk_int32_t, DUK_INT32_MIN, DUK_INT32_MAX);
#endif
}

DUK_INTERNAL duk_uint32_t duk_double_to_uint32_t(duk_double_t x) {
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	return (duk_uint32_t) x;
#else
	DUK__DOUBLE_INT_CAST1(duk_uint32_t, DUK_UINT32_MIN, DUK_UINT32_MAX);
#endif
}

/* Largest IEEE double that doesn't round to infinity in the default rounding
 * mode.  The exact midpoint between (1 - 2^(-24)) * 2^128 and 2^128 rounds to
 * infinity, at least on x64.  This number is one double unit below that
 * midpoint.  See misc/float_cast.c.
 */
#define DUK__FLOAT_ROUND_LIMIT      340282356779733623858607532500980858880.0

/* Maximum IEEE float.  Double-to-float conversion above this would be out of
 * range and thus technically undefined behavior.
 */
#define DUK__FLOAT_MAX              340282346638528859811704183484516925440.0

DUK_INTERNAL duk_float_t duk_double_to_float_t(duk_double_t x) {
	/* Even a double-to-float cast is technically undefined behavior if
	 * the double is out-of-range.  C99 Section 6.3.1.5:
	 *
	 *   If the value being converted is in the range of values that can
	 *   be represented but cannot be represented exactly, the result is
	 *   either the nearest higher or nearest lower representable value,
	 *   chosen in an implementation-defined manner.  If the value being
	 *   converted is outside the range of values that can be represented,
	 *   the behavior is undefined.
	 */
#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	return (duk_float_t) x;
#else
	duk_double_t t;

	t = DUK_FABS(x);
	DUK_ASSERT((DUK_ISNAN(x) && DUK_ISNAN(t)) ||
	           (!DUK_ISNAN(x) && !DUK_ISNAN(t)));

	if (DUK_LIKELY(t <= DUK__FLOAT_MAX)) {
		/* Standard in-range case, try to get here with a minimum
		 * number of checks and branches.
		 */
		DUK_ASSERT(!DUK_ISNAN(x));
		return (duk_float_t) x;
	} else if (t <= DUK__FLOAT_ROUND_LIMIT) {
		/* Out-of-range, but rounds to min/max float. */
		DUK_ASSERT(!DUK_ISNAN(x));
		if (x < 0.0) {
			return (duk_float_t) -DUK__FLOAT_MAX;
		} else {
			return (duk_float_t) DUK__FLOAT_MAX;
		}
	} else if (DUK_ISNAN(x)) {
		/* Assumes double NaN -> float NaN considered "in range". */
		DUK_ASSERT(DUK_ISNAN(x));
		return (duk_float_t) x;
	} else {
		/* Out-of-range, rounds to +/- Infinity. */
		if (x < 0.0) {
			return (duk_float_t) -DUK_DOUBLE_INFINITY;
		} else {
			return (duk_float_t) DUK_DOUBLE_INFINITY;
		}
	}
#endif
}

/* automatic undefs */
#undef DUK__DOUBLE_INT_CAST1
#undef DUK__DOUBLE_INT_CAST2
#undef DUK__DOUBLE_INT_CAST3
#undef DUK__DOUBLE_INT_CAST4
#undef DUK__FLOAT_MAX
#undef DUK__FLOAT_ROUND_LIMIT
/*
 *  IEEE double helpers.
 */

/* #include duk_internal.h -> already included */

DUK_INTERNAL duk_bool_t duk_double_is_anyinf(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	return DUK_DBLUNION_IS_ANYINF(&du);
}

DUK_INTERNAL duk_bool_t duk_double_is_posinf(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	return DUK_DBLUNION_IS_POSINF(&du);
}

DUK_INTERNAL duk_bool_t duk_double_is_neginf(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	return DUK_DBLUNION_IS_NEGINF(&du);
}

DUK_INTERNAL duk_bool_t duk_double_is_nan(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	/* Assumes we're dealing with a Duktape internal NaN which is
	 * NaN normalized if duk_tval requires it.
	 */
	DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
	return DUK_DBLUNION_IS_NAN(&du);
}

DUK_INTERNAL duk_bool_t duk_double_is_nan_or_zero(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	/* Assumes we're dealing with a Duktape internal NaN which is
	 * NaN normalized if duk_tval requires it.
	 */
	DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
	return DUK_DBLUNION_IS_NAN(&du) || DUK_DBLUNION_IS_ANYZERO(&du);
}

DUK_INTERNAL duk_bool_t duk_double_is_nan_or_inf(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	/* If exponent is 0x7FF the argument is either a NaN or an
	 * infinity.  We don't need to check any other fields.
	 */
#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
	return (du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x000000007ff00000)) == DUK_U64_CONSTANT(0x000000007ff00000);
#else
	return (du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7ff0000000000000)) == DUK_U64_CONSTANT(0x7ff0000000000000);
#endif
#else
	return (du.ui[DUK_DBL_IDX_UI0] & 0x7ff00000UL) == 0x7ff00000UL;
#endif
}

DUK_INTERNAL duk_bool_t duk_double_is_nan_zero_inf(duk_double_t x) {
	duk_double_union du;
#if defined(DUK_USE_64BIT_OPS)
	duk_uint64_t t;
#else
	duk_uint32_t t;
#endif
	du.d = x;
#if defined(DUK_USE_64BIT_OPS)
#if defined(DUK_USE_DOUBLE_ME)
	t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x000000007ff00000);
	if (t == DUK_U64_CONSTANT(0x0000000000000000)) {
		t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x0000000080000000);
		return t == 0;
	}
	if (t == DUK_U64_CONSTANT(0x000000007ff00000)) {
		return 1;
	}
#else
	t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7ff0000000000000);
	if (t == DUK_U64_CONSTANT(0x0000000000000000)) {
		t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x8000000000000000);
		return t == 0;
	}
	if (t == DUK_U64_CONSTANT(0x7ff0000000000000)) {
		return 1;
	}
#endif
#else
	t = du.ui[DUK_DBL_IDX_UI0] & 0x7ff00000UL;
	if (t == 0x00000000UL) {
		return DUK_DBLUNION_IS_ANYZERO(&du);
	}
	if (t == 0x7ff00000UL) {
		return 1;
	}
#endif
	return 0;
}

DUK_INTERNAL duk_small_uint_t duk_double_signbit(duk_double_t x) {
	duk_double_union du;
	du.d = x;
	return (duk_small_uint_t) DUK_DBLUNION_GET_SIGNBIT(&du);
}

DUK_INTERNAL duk_double_t duk_double_trunc_towards_zero(duk_double_t x) {
	/* XXX: optimize */
	duk_small_uint_t s = duk_double_signbit(x);
	x = DUK_FLOOR(DUK_FABS(x));  /* truncate towards zero */
	if (s) {
		x = -x;
	}
	return x;
}

DUK_INTERNAL duk_bool_t duk_double_same_sign(duk_double_t x, duk_double_t y) {
	duk_double_union du1;
	duk_double_union du2;
	du1.d = x;
	du2.d = y;

	return (((du1.ui[DUK_DBL_IDX_UI0] ^ du2.ui[DUK_DBL_IDX_UI0]) & 0x80000000UL) == 0);
}

DUK_INTERNAL duk_double_t duk_double_fmin(duk_double_t x, duk_double_t y) {
	/* Doesn't replicate fmin() behavior exactly: for fmin() if one
	 * argument is a NaN, the other argument should be returned.
	 * Duktape doesn't rely on this behavior so the replacement can
	 * be simplified.
	 */
	return (x < y ? x : y);
}

DUK_INTERNAL duk_double_t duk_double_fmax(duk_double_t x, duk_double_t y) {
	/* Doesn't replicate fmax() behavior exactly: for fmax() if one
	 * argument is a NaN, the other argument should be returned.
	 * Duktape doesn't rely on this behavior so the replacement can
	 * be simplified.
	 */
	return (x > y ? x : y);
}

DUK_INTERNAL duk_bool_t duk_double_is_finite(duk_double_t x) {
	return !duk_double_is_nan_or_inf(x);
}

DUK_INTERNAL duk_bool_t duk_double_is_integer(duk_double_t x) {
	if (duk_double_is_nan_or_inf(x)) {
		return 0;
	} else {
		return duk_double_equals(duk_js_tointeger_number(x), x);
	}
}

DUK_INTERNAL duk_bool_t duk_double_is_safe_integer(duk_double_t x) {
	/* >>> 2**53-1
	 * 9007199254740991
	 */
	return duk_double_is_integer(x) && DUK_FABS(x) <= 9007199254740991.0;
}

/* Check whether a duk_double_t is a whole number in the 32-bit range (reject
 * negative zero), and if so, return a duk_int32_t.
 * For compiler use: don't allow negative zero as it will cause trouble with
 * LDINT+LDINTX, positive zero is OK.
 */
DUK_INTERNAL duk_bool_t duk_is_whole_get_int32_nonegzero(duk_double_t x, duk_int32_t *ival) {
	duk_int32_t t;

	t = duk_double_to_int32_t(x);
	if (!duk_double_equals((duk_double_t) t, x)) {
		return 0;
	}
	if (t == 0) {
		duk_double_union du;
		du.d = x;
		if (DUK_DBLUNION_HAS_SIGNBIT(&du)) {
			return 0;
		}
	}
	*ival = t;
	return 1;
}

/* Check whether a duk_double_t is a whole number in the 32-bit range, and if
 * so, return a duk_int32_t.
 */
DUK_INTERNAL duk_bool_t duk_is_whole_get_int32(duk_double_t x, duk_int32_t *ival) {
	duk_int32_t t;

	t = duk_double_to_int32_t(x);
	if (!duk_double_equals((duk_double_t) t, x)) {
		return 0;
	}
	*ival = t;
	return 1;
}

/* Division: division by zero is undefined behavior (and may in fact trap)
 * so it needs special handling for portability.
 */

DUK_INTERNAL DUK_INLINE duk_double_t duk_double_div(duk_double_t x, duk_double_t y) {
#if !defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
	if (DUK_UNLIKELY(duk_double_equals(y, 0.0) != 0)) {
		/* In C99+ division by zero is undefined behavior so
		 * avoid it entirely.  Hopefully the compiler is
		 * smart enough to avoid emitting any actual code
		 * because almost all practical platforms behave as
		 * expected.
		 */
		if (x > 0.0) {
			if (DUK_SIGNBIT(y)) {
				return -DUK_DOUBLE_INFINITY;
			} else {
				return DUK_DOUBLE_INFINITY;
			}
		} else if (x < 0.0) {
			if (DUK_SIGNBIT(y)) {
				return DUK_DOUBLE_INFINITY;
			} else {
				return -DUK_DOUBLE_INFINITY;
			}
		} else {
			/* +/- 0, NaN */
			return DUK_DOUBLE_NAN;
		}
	}
#endif

	return x / y;
}

/* Double and float byteorder changes. */

DUK_INTERNAL DUK_INLINE void duk_dblunion_host_to_little(duk_double_union *u) {
#if defined(DUK_USE_DOUBLE_LE)
	/* HGFEDCBA -> HGFEDCBA */
	DUK_UNREF(u);
#elif defined(DUK_USE_DOUBLE_ME)
	duk_uint32_t a, b;

	/* DCBAHGFE -> HGFEDCBA */
	a = u->ui[0];
	b = u->ui[1];
	u->ui[0] = b;
	u->ui[1] = a;
#elif defined(DUK_USE_DOUBLE_BE)
	/* ABCDEFGH -> HGFEDCBA */
#if defined(DUK_USE_64BIT_OPS)
	u->ull[0] = DUK_BSWAP64(u->ull[0]);
#else
	duk_uint32_t a, b;

	a = u->ui[0];
	b = u->ui[1];
	u->ui[0] = DUK_BSWAP32(b);
	u->ui[1] = DUK_BSWAP32(a);
#endif
#else
#error internal error
#endif
}

DUK_INTERNAL DUK_INLINE void duk_dblunion_little_to_host(duk_double_union *u) {
	duk_dblunion_host_to_little(u);
}

DUK_INTERNAL DUK_INLINE void duk_dblunion_host_to_big(duk_double_union *u) {
#if defined(DUK_USE_DOUBLE_LE)
	/* HGFEDCBA -> ABCDEFGH */
#if defined(DUK_USE_64BIT_OPS)
	u->ull[0] = DUK_BSWAP64(u->ull[0]);
#else
	duk_uint32_t a, b;

	a = u->ui[0];
	b = u->ui[1];
	u->ui[0] = DUK_BSWAP32(b);
	u->ui[1] = DUK_BSWAP32(a);
#endif
#elif defined(DUK_USE_DOUBLE_ME)
	duk_uint32_t a, b;

	/* DCBAHGFE -> ABCDEFGH */
	a = u->ui[0];
	b = u->ui[1];
	u->ui[0] = DUK_BSWAP32(a);
	u->ui[1] = DUK_BSWAP32(b);
#elif defined(DUK_USE_DOUBLE_BE)
	/* ABCDEFGH -> ABCDEFGH */
	DUK_UNREF(u);
#else
#error internal error
#endif
}

DUK_INTERNAL DUK_INLINE void duk_dblunion_big_to_host(duk_double_union *u) {
	duk_dblunion_host_to_big(u);
}

DUK_INTERNAL DUK_INLINE void duk_fltunion_host_to_big(duk_float_union *u) {
#if defined(DUK_USE_DOUBLE_LE) || defined(DUK_USE_DOUBLE_ME)
	/* DCBA -> ABCD */
	u->ui[0] = DUK_BSWAP32(u->ui[0]);
#elif defined(DUK_USE_DOUBLE_BE)
	/* ABCD -> ABCD */
	DUK_UNREF(u);
#else
#error internal error
#endif
}

DUK_INTERNAL DUK_INLINE void duk_fltunion_big_to_host(duk_float_union *u) {
	duk_fltunion_host_to_big(u);
}

/* Comparison: ensures comparison operates on exactly correct types, avoiding
 * some floating point comparison pitfalls (e.g. atan2() assertions failed on
 * -m32 with direct comparison, even with explicit casts).
 */
#if defined(DUK_USE_GCC_PRAGMAS)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wfloat-equal"
#elif defined(DUK_USE_CLANG_PRAGMAS)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wfloat-equal"
#endif

DUK_INTERNAL DUK_ALWAYS_INLINE duk_bool_t duk_double_equals(duk_double_t x, duk_double_t y) {
	return x == y;
}

DUK_INTERNAL DUK_ALWAYS_INLINE duk_bool_t duk_float_equals(duk_float_t x, duk_float_t y) {
	return x == y;
}
#if defined(DUK_USE_GCC_PRAGMAS)
#pragma GCC diagnostic pop
#elif defined(DUK_USE_CLANG_PRAGMAS)
#pragma clang diagnostic pop
#endif
/*
 *  Hash function duk_util_hashbytes().
 *
 *  Currently, 32-bit MurmurHash2.
 *
 *  Don't rely on specific hash values; hash function may be endianness
 *  dependent, for instance.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_STRHASH_DENSE)
/* 'magic' constants for Murmurhash2 */
#define DUK__MAGIC_M  ((duk_uint32_t) 0x5bd1e995UL)
#define DUK__MAGIC_R  24

DUK_INTERNAL duk_uint32_t duk_util_hashbytes(const duk_uint8_t *data, duk_size_t len, duk_uint32_t seed) {
	duk_uint32_t h = seed ^ ((duk_uint32_t) len);

	while (len >= 4) {
		/* Portability workaround is required for platforms without
		 * unaligned access.  The replacement code emulates little
		 * endian access even on big endian architectures, which is
		 * OK as long as it is consistent for a build.
		 */
#if defined(DUK_USE_HASHBYTES_UNALIGNED_U32_ACCESS)
		duk_uint32_t k = *((const duk_uint32_t *) (const void *) data);
#else
		duk_uint32_t k = ((duk_uint32_t) data[0]) |
		                 (((duk_uint32_t) data[1]) << 8) |
		                 (((duk_uint32_t) data[2]) << 16) |
		                 (((duk_uint32_t) data[3]) << 24);
#endif

		k *= DUK__MAGIC_M;
		k ^= k >> DUK__MAGIC_R;
		k *= DUK__MAGIC_M;
		h *= DUK__MAGIC_M;
		h ^= k;
		data += 4;
		len -= 4;
	}

	switch (len) {
	case 3: h ^= data[2] << 16;
	case 2: h ^= data[1] << 8;
	case 1: h ^= data[0];
	        h *= DUK__MAGIC_M;
        }

	h ^= h >> 13;
	h *= DUK__MAGIC_M;
	h ^= h >> 15;

	return h;
}
#endif  /* DUK_USE_STRHASH_DENSE */

/* automatic undefs */
#undef DUK__MAGIC_M
#undef DUK__MAGIC_R
/*
 *  Memory utils.
 */

/* #include duk_internal.h -> already included */

#if defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
DUK_INTERNAL DUK_INLINE duk_small_int_t duk_memcmp_unsafe(const void *s1, const void *s2, duk_size_t len) {
	DUK_ASSERT(s1 != NULL || len == 0U);
	DUK_ASSERT(s2 != NULL || len == 0U);
	return DUK_MEMCMP(s1, s2, (size_t) len);
}

DUK_INTERNAL DUK_INLINE duk_small_int_t duk_memcmp(const void *s1, const void *s2, duk_size_t len) {
	DUK_ASSERT(s1 != NULL);
	DUK_ASSERT(s2 != NULL);
	return DUK_MEMCMP(s1, s2, (size_t) len);
}
#else  /* DUK_USE_ALLOW_UNDEFINED_BEHAVIOR */
DUK_INTERNAL DUK_INLINE duk_small_int_t duk_memcmp_unsafe(const void *s1, const void *s2, duk_size_t len) {
	DUK_ASSERT(s1 != NULL || len == 0U);
	DUK_ASSERT(s2 != NULL || len == 0U);
	if (DUK_UNLIKELY(len == 0U)) {
		return 0;
	}
	DUK_ASSERT(s1 != NULL);
	DUK_ASSERT(s2 != NULL);
	return duk_memcmp(s1, s2, len);
}

DUK_INTERNAL DUK_INLINE duk_small_int_t duk_memcmp(const void *s1, const void *s2, duk_size_t len) {
	DUK_ASSERT(s1 != NULL);
	DUK_ASSERT(s2 != NULL);
	return DUK_MEMCMP(s1, s2, (size_t) len);
}
#endif  /* DUK_USE_ALLOW_UNDEFINED_BEHAVIOR */
/*
 *  A tiny random number generator used for Math.random() and other internals.
 *
 *  Default algorithm is xoroshiro128+: http://xoroshiro.di.unimi.it/xoroshiro128plus.c
 *  with SplitMix64 seed preparation: http://xorshift.di.unimi.it/splitmix64.c.
 *
 *  Low memory targets and targets without 64-bit types use a slightly smaller
 *  (but slower) algorithm by Adi Shamir:
 *  http://www.woodmann.com/forum/archive/index.php/t-3100.html.
 *
 */

/* #include duk_internal.h -> already included */

#if !defined(DUK_USE_GET_RANDOM_DOUBLE)

#if defined(DUK_USE_PREFER_SIZE) || !defined(DUK_USE_64BIT_OPS)
#define DUK__RANDOM_SHAMIR3OP
#else
#define DUK__RANDOM_XOROSHIRO128PLUS
#endif

#if defined(DUK__RANDOM_SHAMIR3OP)
#define DUK__UPDATE_RND(rnd) do { \
		(rnd) += ((rnd) * (rnd)) | 0x05UL; \
		(rnd) = ((rnd) & 0xffffffffUL);       /* if duk_uint32_t is exactly 32 bits, this is a NOP */ \
	} while (0)

#define DUK__RND_BIT(rnd)  ((rnd) >> 31)  /* only use the highest bit */

DUK_INTERNAL void duk_util_tinyrandom_prepare_seed(duk_hthread *thr) {
	DUK_UNREF(thr);  /* Nothing now. */
}

DUK_INTERNAL duk_double_t duk_util_tinyrandom_get_double(duk_hthread *thr) {
	duk_double_t t;
	duk_small_int_t n;
	duk_uint32_t rnd;

	rnd = thr->heap->rnd_state;

	n = 53;  /* enough to cover the whole mantissa */
	t = 0.0;

	do {
		DUK__UPDATE_RND(rnd);
		t += DUK__RND_BIT(rnd);
		t /= 2.0;
	} while (--n);

	thr->heap->rnd_state = rnd;

	DUK_ASSERT(t >= (duk_double_t) 0.0);
	DUK_ASSERT(t < (duk_double_t) 1.0);

	return t;
}
#endif  /* DUK__RANDOM_SHAMIR3OP */

#if defined(DUK__RANDOM_XOROSHIRO128PLUS)
DUK_LOCAL DUK_ALWAYS_INLINE duk_uint64_t duk__rnd_splitmix64(duk_uint64_t *x) {
	duk_uint64_t z;
	z = (*x += DUK_U64_CONSTANT(0x9E3779B97F4A7C15));
	z = (z ^ (z >> 30U)) * DUK_U64_CONSTANT(0xBF58476D1CE4E5B9);
	z = (z ^ (z >> 27U)) * DUK_U64_CONSTANT(0x94D049BB133111EB);
	return z ^ (z >> 31U);
}

DUK_LOCAL DUK_ALWAYS_INLINE duk_uint64_t duk__rnd_rotl(const duk_uint64_t x, duk_small_uint_t k) {
	return (x << k) | (x >> (64U - k));
}

DUK_LOCAL DUK_ALWAYS_INLINE duk_uint64_t duk__xoroshiro128plus(duk_uint64_t *s) {
	duk_uint64_t s0;
	duk_uint64_t s1;
	duk_uint64_t res;

	s0 = s[0];
	s1 = s[1];
	res = s0 + s1;
	s1 ^= s0;
	s[0] = duk__rnd_rotl(s0, 55) ^ s1 ^ (s1 << 14U);
	s[1] = duk__rnd_rotl(s1, 36);

	return res;
}

DUK_INTERNAL void duk_util_tinyrandom_prepare_seed(duk_hthread *thr) {
	duk_small_uint_t i;
	duk_uint64_t x;

	/* Mix both halves of the initial seed with SplitMix64.  The intent
	 * is to ensure that very similar raw seeds (which is usually the case
	 * because current seed is Date.now()) result in different xoroshiro128+
	 * seeds.
	 */
	x = thr->heap->rnd_state[0];  /* Only [0] is used as input here. */
	for (i = 0; i < 64; i++) {
		thr->heap->rnd_state[i & 0x01] = duk__rnd_splitmix64(&x);  /* Keep last 2 values. */
	}
}

DUK_INTERNAL duk_double_t duk_util_tinyrandom_get_double(duk_hthread *thr) {
	duk_uint64_t v;
	duk_double_union du;

	/* For big and little endian the integer and IEEE double byte order
	 * is the same so a direct assignment works.  For mixed endian the
	 * 32-bit parts must be swapped.
	 */
	v = (DUK_U64_CONSTANT(0x3ff) << 52U) | (duk__xoroshiro128plus((duk_uint64_t *) thr->heap->rnd_state) >> 12U);
	du.ull[0] = v;
#if defined(DUK_USE_DOUBLE_ME)
	do {
		duk_uint32_t tmp;
		tmp = du.ui[0];
		du.ui[0] = du.ui[1];
		du.ui[1] = tmp;
	} while (0);
#endif
	return du.d - 1.0;
}
#endif  /* DUK__RANDOM_XOROSHIRO128PLUS */

#endif  /* !DUK_USE_GET_RANDOM_DOUBLE */

/* automatic undefs */
#undef DUK__RANDOM_SHAMIR3OP
#undef DUK__RANDOM_XOROSHIRO128PLUS
#undef DUK__RND_BIT
#undef DUK__UPDATE_RND
