/* inflate.h -- internal inflate state definition
 * Copyright (C) 1995-2004 Mark Adler
* SPDX-License-Identifier:	GPL-2.0+
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* WARNING: this file should *not* be used by applications. It is
   part of the implementation of the compression library and is
   subject to change. Applications should only use zlib.h.
 */

/* define NO_GZIP when compiling if you want to disable gzip header and
   trailer decoding by inflate().  NO_GZIP would be used to avoid linking in
   the crc code when it is not needed.  For shared libraries, gzip decoding
   should be left enabled. */
#ifndef NO_GZIP
#define GUNZIP
#endif

/* Possible inflate modes between inflate() calls */
typedef enum {
	HEAD, /* i: waiting for magic header */
	FLAGS, /* i: waiting for method and flags (gzip) */
	TIME, /* i: waiting for modification time (gzip) */
	OS, /* i: waiting for extra flags and operating system (gzip) */
	EXLEN, /* i: waiting for extra length (gzip) */
	EXTRA, /* i: waiting for extra bytes (gzip) */
	NAME, /* i: waiting for end of file name (gzip) */
	COMMENT, /* i: waiting for end of comment (gzip) */
	HCRC, /* i: waiting for header crc (gzip) */
	DICTID, /* i: waiting for dictionary check value */
	DICT, /* waiting for inflateSetDictionary() call */
	TYPE, /* i: waiting for type bits, including last-flag bit */
	TYPEDO, /* i: same, but skip check to exit inflate on new block */
	STORED, /* i: waiting for stored size (length and complement) */
	COPY, /* i/o: waiting for input or output to copy stored block */
	TABLE, /* i: waiting for dynamic block table lengths */
	LENLENS, /* i: waiting for code length code lengths */
	CODELENS, /* i: waiting for length/lit and distance code lengths */
	LEN, /* i: waiting for length/lit code */
	LENEXT, /* i: waiting for length extra bits */
	DIST, /* i: waiting for distance code */
	DISTEXT, /* i: waiting for distance extra bits */
	MATCH, /* o: waiting for output space to copy string */
	LIT, /* o: waiting for output space to write literal */
	CHECK, /* i: waiting for 32-bit check value */
	LENGTH, /* i: waiting for 32-bit length (gzip) */
	DONE, /* finished check, done -- remain here until reset */
	BAD, /* got a data error -- remain here until reset */
	MEM, /* got an inflate() memory error -- remain here until reset */
	SYNC /* looking for synchronization bytes to restart inflate() */
} inflate_mode;

/*
    State transitions between above modes -

    (most modes can go to the BAD or MEM mode -- not shown for clarity)

		Process header:
				HEAD -> (gzip) or (zlib)
				(gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
				NAME -> COMMENT -> HCRC -> TYPE
				(zlib) -> DICTID or TYPE
				DICTID -> DICT -> TYPE
			Read deflate blocks:
				TYPE -> STORED or TABLE or LEN or CHECK
				STORED -> COPY -> TYPE
				TABLE -> LENLENS -> CODELENS -> LEN
			Read deflate codes:
				LEN -> LENEXT or LIT or TYPE
				LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
				LIT -> LEN
			Process trailer:
				CHECK -> LENGTH -> DONE
 */

/* state maintained between inflate() calls.  Approximately 7K bytes. */
struct inflate_state {
	inflate_mode mode; /* current inflate mode */
	int last; /* true if processing last block */
	int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
	int havedict; /* true if dictionary provided */
	int flags; /* gzip header method and flags (0 if zlib) */
	unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
	unsigned long check; /* protected copy of check value */
	unsigned long total; /* protected copy of output count */
	gz_headerp head; /* where to save gzip header information */
	/* sliding window */
	unsigned wbits; /* log base 2 of requested window size */
	unsigned wsize; /* window size or zero if not using window */
	unsigned whave; /* valid bytes in the window */
	unsigned write; /* window write index */
	unsigned char FAR *window; /* allocated sliding window, if needed */
	/* bit accumulator */
	unsigned long hold; /* input bit accumulator */
	unsigned bits; /* number of bits in "in" */
	/* for string and stored block copying */
	unsigned length; /* literal or length of data to copy */
	unsigned offset; /* distance back to copy string from */
	/* for table and code decoding */
	unsigned extra; /* extra bits needed */
	/* fixed and dynamic code tables */
	code const FAR *lencode; /* starting table for length/literal codes */
	code const FAR *distcode; /* starting table for distance codes */
	unsigned lenbits; /* index bits for lencode */
	unsigned distbits; /* index bits for distcode */
	/* dynamic table building */
	unsigned ncode; /* number of code length code lengths */
	unsigned nlen; /* number of length code lengths */
	unsigned ndist; /* number of distance code lengths */
	unsigned have; /* number of code lengths in lens[] */
	code FAR *next; /* next available space in codes[] */
	unsigned short lens[320]; /* temporary storage for code lengths */
	unsigned short work[288]; /* work area for code table building */
	code codes[ENOUGH]; /* space for code tables */
};
