/*
Copyright (C) 1994-2016 Lawrence Livermore National Security, LLC.
LLNL-CODE-425250.
All rights reserved.

This file is part of Silo. For details, see silo.llnl.gov.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the disclaimer below.
   * Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the disclaimer (as noted
     below) in the documentation and/or other materials provided with
     the distribution.
   * Neither the name of the LLNS/LLNL nor the names of its
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

THIS SOFTWARE  IS PROVIDED BY  THE COPYRIGHT HOLDERS  AND CONTRIBUTORS
"AS  IS" AND  ANY EXPRESS  OR IMPLIED  WARRANTIES, INCLUDING,  BUT NOT
LIMITED TO, THE IMPLIED  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A  PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN  NO  EVENT SHALL  LAWRENCE
LIVERMORE  NATIONAL SECURITY, LLC,  THE U.S.  DEPARTMENT OF  ENERGY OR
CONTRIBUTORS BE LIABLE FOR  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR  CONSEQUENTIAL DAMAGES  (INCLUDING, BUT NOT  LIMITED TO,
PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS  OF USE,  DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER  IN CONTRACT, STRICT LIABILITY,  OR TORT (INCLUDING
NEGLIGENCE OR  OTHERWISE) ARISING IN  ANY WAY OUT  OF THE USE  OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

This work was produced at Lawrence Livermore National Laboratory under
Contract  No.   DE-AC52-07NA27344 with  the  DOE.  Neither the  United
States Government  nor Lawrence  Livermore National Security,  LLC nor
any of  their employees,  makes any warranty,  express or  implied, or
assumes   any   liability   or   responsibility  for   the   accuracy,
completeness, or usefulness of any information, apparatus, product, or
process  disclosed, or  represents  that its  use  would not  infringe
privately-owned   rights.  Any  reference   herein  to   any  specific
commercial products,  process, or  services by trade  name, trademark,
manufacturer or otherwise does not necessarily constitute or imply its
endorsement,  recommendation,   or  favoring  by   the  United  States
Government or Lawrence Livermore National Security, LLC. The views and
opinions  of authors  expressed  herein do  not  necessarily state  or
reflect those  of the United  States Government or  Lawrence Livermore
National  Security, LLC,  and shall  not  be used  for advertising  or
product endorsement purposes.
*/
/* Define this symbol BEFORE including hdf5.h to indicate the HDF5 code
   in this file uses version 1.6 of the HDF5 API. This is harmless for
   versions of HDF5 before 1.8 and ensures correct compilation with
   version 1.8 and thereafter. When, and if, the HDF5 code in this file
   is explicitly upgraded to the 1.8 API, this symbol should be removed. */
#define H5_USE_16_API

#include <config.h>
#if defined(HAVE_HDF5_H) && defined(HAVE_LIBHDF5)

#include "hdf5.h"

/* useful macro for comparing HDF5 versions */
#include "hdf5_version_ge.h"

#if HDF5_VERSION_GE(1,8,4)

/* The _GNU_SOURCE wrapper logic is to enable the O_DIRECT flag */
#ifdef __linux__
#define _GNU_SOURCE
#endif

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h> /* for snprintf */
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifndef _WIN32
#include <unistd.h>
#endif

#ifdef __linux__
#undef _GNU_SOURCE
#endif

/*
   TO DO:

     *1. Examine file block alignment with HDF5 lib metadata allocations
      2. On systems that support O_DIRECT, try posix_madvise/posix_memalign
      3. Support partial last block
      4. Aggregate multiple blocks
     *5. allow an 'auto' block count or 'max-N'
      6. If 5, add DBFreeSomeSiloVFDBlocks
      7. Compare with sec2 VFD, PDB
     *8. Pre-empt raw data blocks over meta data blocks
      9. Move mdc_config from silo_hdf5.c to this file
    *10. Does mdc_config really matter now?
     11. Fix skipping truncate (maybe by 3)
    *12. Sanity check block size on read relative to write.
     13. Get performance studies on other systems
     14. Study read performance too.
     15. Move to DICHOTOMY and write all meta blocks at end of file.
     16. Write blocks from different MPI tasks to same file. On read
         back, need to specify which 'task' but should otherwise work.
     17. Use direct I/O where possible (and appropriate).
     18. Capture I/O statistics here.
     19. Set mdc_config to never preempt (chews up memory in lib),
         all writes for md will come on close.
     20. Use COMPACT storage mode in driver for small datasets.

*/

/* Define this symbol BEFORE including hdf5.h to indicate the HDF5 code
   in this file uses version 1.6 of the HDF5 API. This is harmless for
   versions of HDF5 before 1.8 and ensures correct compilation with
   version 1.8 and thereafter. When, and if, the HDF5 code in this file
   is explicitly upgraded to the 1.8 API, this symbol should be removed. */
#define H5_USE_16_API

#include "hdf5.h"
#include "H5FDsilo.h"

#ifdef _WIN32
#include <windows.h>
#include <io.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <share.h>
#endif

#ifdef MAX
#undef MAX
#endif
#define MAX(X,Y)	((X)>(Y)?(X):(Y))

/* File operations */
#define OP_UNKNOWN      0
#define OP_READ         1
#define OP_WRITE        2

#define EXACT		0
#define CLOSEST		1

#define SILO_BLKSZ_PROPNAME "silo_block_size"
#define SILO_BLKCNT_PROPNAME "silo_block_count"
#define SILO_LOGSTS_PROPNAME "silo_log_stats"
#define SILO_USEDIR_PROPNAME "silo_use_direct"

/* definitions related to the file stat utilities.
 * For Unix, if off_t is not 64bit big, try use the pseudo-standard
 * xxx64 versions if available.
 */
#if !defined(HDfstat) || !defined(HDstat)
    #if H5_SIZEOF_OFF_T!=8 && H5_SIZEOF_OFF64_T==8 && defined(H5_HAVE_STAT64)
        #ifndef HDfstat
            #define HDfstat(F,B)        fstat64(F,B)
        #endif /* HDfstat */
        #ifndef HDstat
            #define HDstat(S,B)         stat64(S,B)
        #endif /* HDstat */
        typedef struct stat64       h5_stat_t;
        typedef off64_t             h5_stat_size_t;
        #define H5_SIZEOF_H5_STAT_SIZE_T H5_SIZEOF_OFF64_T
    #else /* H5_SIZEOF_OFF_T!=8 && ... */
        #ifndef HDfstat
            #define HDfstat(F,B)        fstat(F,B)
        #endif /* HDfstat */
        #ifndef HDstat
            #define HDstat(S,B)         stat(S,B)
        #endif /* HDstat */
        typedef struct stat         h5_stat_t;
        typedef off_t               h5_stat_size_t;
        #define H5_SIZEOF_H5_STAT_SIZE_T H5_SIZEOF_OFF_T
    #endif /* H5_SIZEOF_OFF_T!=8 && ... */
#endif /* !defined(HDfstat) || !defined(HDstat) */
#ifndef HDlseek
    #ifdef H5_HAVE_LSEEK64
       #define HDlseek(F,O,W)   lseek64(F,O,W)
    #else
       #define HDlseek(F,O,W)   lseek(F,O,W)
    #endif
#endif /* HDlseek */
#ifndef HDassert
    #define HDassert(X)         assert(X)
#endif /* HDassert */
#ifndef HDopen
    #ifdef _WIN32
        typedef int mode_t;
        #define HDopen(S,F,M)           my_sopen_s(S,F,M)
    #else
        #ifdef _O_BINARY
            #define HDopen(S,F,M)       open(S,F|_O_BINARY,M)
        #else
            #define HDopen(S,F,M)       open(S,F,M)
        #endif
    #endif
#endif /* HDopen */
#ifndef HDread
    #define HDread(F,M,Z)               read(F,M,Z)
#endif /* HDread */
#ifndef HDwrite
    #define HDwrite(F,M,Z)              write(F,M,Z)
#endif /* HDwrite */
#ifndef HDftruncate
  #ifdef H5_HAVE_FTRUNCATE64
    #define HDftruncate(F,L)        ftruncate64(F,L)
  #else
    #define HDftruncate(F,L)        ftruncate(F,L)
  #endif
#endif /* HDftruncate */
#ifndef HDmemset
    #define HDmemset(X,C,Z)             memset(X,C,Z)
#endif /* HDmemset */
#define H5F_addr_eq(X,Y)        ((X)!=HADDR_UNDEF &&                          \
                                 (X)==(Y))

static const char *flavors(H5F_mem_t m)
{
    static char tmp[32];

    if (m == H5FD_MEM_DEFAULT)
        return "H5FD_MEM_DEFAULT";
    if (m == H5FD_MEM_SUPER)
        return "H5FD_MEM_SUPER";
    if (m == H5FD_MEM_BTREE)
        return "H5FD_MEM_BTREE";
    if (m == H5FD_MEM_DRAW)
        return "H5FD_MEM_DRAW";
    if (m == H5FD_MEM_GHEAP)
        return "H5FD_MEM_GHEAP";
    if (m == H5FD_MEM_LHEAP)
        return "H5FD_MEM_LHEAP";
    if (m == H5FD_MEM_OHDR)
        return "H5FD_MEM_OHDR";

    sprintf(tmp, "Unknown (%d)", (int) m);
    return tmp;
}


#ifdef H5_HAVE_SNPRINTF
#define H5E_PUSH_HELPER(Func,Cls,Maj,Min,Msg,Ret,Errno)			\
{									\
    char msg[256];							\
    if (Errno != 0)							\
        snprintf(msg, sizeof(msg), Msg "(errno=%d, \"%s\")",	\
            Errno, strerror(Errno));					\
    ret_value = Ret;							\
    H5Epush_ret(Func, Cls, Maj, Min, msg, Ret)				\
}
#else
#define H5E_PUSH_HELPER(Func,Cls,Maj,Min,Msg,Ret,Errno)			\
{									\
    ret_value = Ret;							\
    H5Epush_ret(Func, Cls, Maj, Min, Msg, Ret)				\
}
#endif

typedef struct silo_vfd_hot_block_stats_t_
{
    hsize_t id;
    hsize_t num_block_writes;
    hsize_t num_block_reads;
    float raw_frac;
} silo_vfd_hot_block_stats_t;

typedef struct silo_vfd_stats_t_
{
    /* statistics for this VFD's interaction with the filesystem */
    hsize_t max_block_id;
    hsize_t max_blocks_in_mem;

    hsize_t total_seeks;

    hsize_t num_multiblock_writes;
    hsize_t num_multiblock_reads;

    hsize_t num_blocks_majority_md;
    hsize_t num_blocks_majority_raw;

    hsize_t total_write_count;
    hsize_t total_write_bytes;

    hsize_t total_block_raw_writes;
    hsize_t total_block_raw_re_writes;
    double total_time_in_raw_writes;

    hsize_t total_block_md_writes;
    hsize_t total_block_md_re_writes;
    double total_time_in_md_writes;

    hsize_t total_read_count;
    hsize_t total_read_bytes;

    hsize_t total_block_reads;
    hsize_t total_block_re_reads;
    double total_time_in_reads;

    int num_hot_blocks;
    int max_hot_blocks;
    silo_vfd_hot_block_stats_t *hot_block_list;

    double timestamp_open_started;
    double timestamp_close_finished;

    /* Statistics for HDF5 lib's interaction with this VFD */
    hsize_t total_vfd_raw_write_count;
    hsize_t total_vfd_raw_write_bytes;
    hsize_t vfd_raw_write_count_hist[32];
    hsize_t vfd_raw_write_bytes_hist[32];

    hsize_t total_vfd_md_write_count;
    hsize_t total_vfd_md_write_bytes;
    hsize_t vfd_md_write_count_hist[32];
    hsize_t vfd_md_write_bytes_hist[32];

    hsize_t total_vfd_raw_read_count;
    hsize_t total_vfd_raw_read_bytes;
    hsize_t vfd_raw_read_count_hist[32];
    hsize_t vfd_raw_read_bytes_hist[32];

    hsize_t total_vfd_md_read_count;
    hsize_t total_vfd_md_read_bytes;
    hsize_t vfd_md_read_count_hist[32];
    hsize_t vfd_md_read_bytes_hist[32];

    hsize_t max_hdf5_cache_size;

} silo_vfd_stats_t;

typedef struct silo_vfd_block_bitmap_t_
{
    unsigned char *bitmap;
    hsize_t nbytes;
} silo_vfd_block_bitmap_t;

typedef struct silo_vfd_relevant_blocks_t_
{
    hsize_t  id0,  id1;
    int     off0, off1;
} silo_vfd_relevant_blocks_t;

typedef struct silo_vfd_block_t_
{
    hsize_t id;
    hsize_t age;
    void *buf;
    unsigned dirty;
    hsize_t minmoff, maxmoff;
    hsize_t minroff, maxroff;
} silo_vfd_block_t;

typedef struct silo_vfd_pair_t_ 
{
    int i;
    hsize_t id;
} silo_vfd_pair_t;

static int compare_silo_vfd_pairs(const void *a, const void *b)
{
    silo_vfd_pair_t *paira = (silo_vfd_pair_t*)a;
    silo_vfd_pair_t *pairb = (silo_vfd_pair_t*)b;
    if (paira->id < pairb->id) return -1;
    if (paira->id > pairb->id) return 1;
    return 0;
}

/* The driver identification number, initialized at runtime */
static hid_t H5FD_SILO_g = 0;

/*
 * The description of a file belonging to this driver. The `eoa' and `eof'
 * determine the amount of hdf5 address space in use and the high-water mark
 * of the file (the current size of the underlying Unix file). The `pos'
 * value is used to eliminate file position updates when they would be a
 * no-op. Unfortunately we've found systems that use separate file position
 * indicators for reading and writing so the lseek can only be eliminated if
 * the current operation is the same as the previous operation.  When opening
 * a file the `eof' will be set to the current file size, `eoa' will be set
 * to zero, `pos' will be set to H5F_ADDR_UNDEF (as it is when an error
 * occurs), and `op' will be set to H5F_OP_UNKNOWN.
 */
typedef struct H5FD_silo_t {
    H5FD_t	pub;			/*public stuff, must be first	*/
    int         fd;			/* file descriptor */
    haddr_t	eoa;			/*end of allocated region	*/
    haddr_t	eof;			/*end of file; current file size*/
    haddr_t     file_eof;
    haddr_t	pos;			/*current file I/O position	*/
    int         op;			/*last operation		*/
    unsigned    write_access;  		/* Flag to indicate the file was opened with write access */
    hsize_t     block_size;
    hsize_t     op_counter;
    silo_vfd_block_t *block_list;
    int         max_blocks;
    int         num_blocks;
    int         log_stats;
    char       *log_name;
    int         use_direct;
    silo_vfd_block_bitmap_t was_written_map;
    silo_vfd_block_bitmap_t was_in_mem_map;
    silo_vfd_stats_t stats;
#ifndef _WIN32
    /*
     * On most systems the combination of device and i-node number uniquely
     * identify a file.
     */
    dev_t	device;			/*file device number		*/
#ifdef H5_VMS
    ino_t       inode[3];               /*file i-node number            */
#else
    ino_t       inode;                  /*file i-node number            */
#endif /*H5_VMS*/
#else
    /*
     * On _WIN32 the low-order word of a unique identifier associated with the
     * file and the volume serial number uniquely identify a file. This number
     * (which, both? -rpm) may change when the system is restarted or when the
     * file is opened. After a process opens a file, the identifier is
     * constant until the file is closed. An application can use this
     * identifier and the volume serial number to determine whether two
     * handles refer to the same file.
     */
    DWORD fileindexlo;
    DWORD fileindexhi;
#endif
    /* Information from properties set by 'h5repart' tool */
    hbool_t     fam_to_sec2;    /* Whether to eliminate the family driver info
                                 * and convert this file to a single file */
} H5FD_silo_t;

#ifdef H5_HAVE_LSEEK64
#   define file_offset_t        off64_t
#elif defined (_WIN32) && !defined(__MWERKS__)
# /*MSVC*/
#   define file_offset_t        __int64
#else
#   define file_offset_t        off_t
#endif

/*
 * These macros check for overflow of various quantities.  These macros
 * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
 *
 * ADDR_OVERFLOW:	Checks whether a file address of type `haddr_t'
 *			is too large to be represented by the second argument
 *			of the file seek function.
 *
 * SIZE_OVERFLOW:	Checks whether a buffer size of type `hsize_t' is too
 *			large to be represented by the `size_t' type.
 *
 * REGION_OVERFLOW:	Checks whether an address and size pair describe data
 *			which can be addressed entirely by the second
 *			argument of the file seek function.
 */
/* adding for windows NT filesystem support. */
#define MAXADDR (((haddr_t)1<<(8*sizeof(file_offset_t)-1))-1)
#define ADDR_OVERFLOW(A)	(HADDR_UNDEF==(A) || ((A) & ~(haddr_t)MAXADDR))
#define SIZE_OVERFLOW(Z)	((Z) & ~(hsize_t)MAXADDR)
#define REGION_OVERFLOW(A,Z)	(ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) || \
    HADDR_UNDEF==(A)+(Z) || (file_offset_t)((A)+(Z))<(file_offset_t)(A))
#define H5_CHECK_OVERFLOW(var, vartype, casttype) \
{                                                 \
    casttype _tmp_overflow = (casttype)(var);     \
    assert((var) == (vartype)_tmp_overflow);      \
}


/* Prototypes */
static hsize_t H5FD_silo_sb_size(H5FD_t *file);
static herr_t H5FD_silo_sb_encode(H5FD_t *file, char *name/*out*/,
                                   unsigned char *buf/*out*/);
static herr_t H5FD_silo_sb_decode(H5FD_t *file, const char *name,
                                   const unsigned char *buf);
static H5FD_t *H5FD_silo_open(const char *name, unsigned flags,
                 hid_t fapl_id, haddr_t maxaddr);
static herr_t H5FD_silo_close(H5FD_t *lf);
static int H5FD_silo_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static herr_t H5FD_silo_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t H5FD_silo_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
static herr_t H5FD_silo_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr);
#if HDF5_VERSION_GE(1,10,4)
static haddr_t H5FD_silo_get_eof(const H5FD_t *_file, H5FD_mem_t type);
#else
static haddr_t H5FD_silo_get_eof(const H5FD_t *_file);
#endif
static herr_t  H5FD_silo_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle);
static herr_t H5FD_silo_read(H5FD_t *lf, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
                size_t size, void *buf);
static herr_t H5FD_silo_write(H5FD_t *lf, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
                size_t size, const void *buf);
static herr_t H5FD_silo_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);

#warning REMOVE ME
#if 0
typedef struct H5FD_class_t {
    const char *name;
    haddr_t maxaddr;
    H5F_close_degree_t fc_degree;
    herr_t  (*terminate)(void);
    hsize_t (*sb_size)(H5FD_t *file);
    herr_t  (*sb_encode)(H5FD_t *file, char *name/*out*/,
                         unsigned char *p/*out*/);
    herr_t  (*sb_decode)(H5FD_t *f, const char *name, const unsigned char *p);
    size_t  fapl_size;
    void *  (*fapl_get)(H5FD_t *file);
    void *  (*fapl_copy)(const void *fapl);
    herr_t  (*fapl_free)(void *fapl);
    size_t  dxpl_size;
    void *  (*dxpl_copy)(const void *dxpl);
    herr_t  (*dxpl_free)(void *dxpl);
    H5FD_t *(*open)(const char *name, unsigned flags, hid_t fapl,
                    haddr_t maxaddr);
    herr_t  (*close)(H5FD_t *file);
    int     (*cmp)(const H5FD_t *f1, const H5FD_t *f2);
    herr_t  (*query)(const H5FD_t *f1, unsigned long *flags);
    herr_t  (*get_type_map)(const H5FD_t *file, H5FD_mem_t *type_map);
    haddr_t (*alloc)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
    herr_t  (*free)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id,
                    haddr_t addr, hsize_t size);
    haddr_t (*get_eoa)(const H5FD_t *file, H5FD_mem_t type);
    herr_t  (*set_eoa)(H5FD_t *file, H5FD_mem_t type, haddr_t addr);
    haddr_t (*get_eof)(const H5FD_t *file, H5FD_mem_t type);
    herr_t  (*get_handle)(H5FD_t *file, hid_t fapl, void**file_handle);
    herr_t  (*read)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl,
                    haddr_t addr, size_t size, void *buffer);
    herr_t  (*write)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl,
                     haddr_t addr, size_t size, const void *buffer);
    herr_t  (*flush)(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
    herr_t  (*truncate)(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
    herr_t  (*lock)(H5FD_t *file, hbool_t rw);
    herr_t  (*unlock)(H5FD_t *file);
    H5FD_mem_t fl_map[H5FD_MEM_NTYPES];
} H5FD_class_t;
#endif

static const H5FD_class_t H5FD_silo_g = {
    "silo",				        /*name			*/
    MAXADDR,				        /*maxaddr		*/
    H5F_CLOSE_WEAK,				/* fc_degree		*/
#if HDF5_VERSION_GE(1,10,4)
    0,                                          /* terminate            */
#endif
    H5FD_silo_sb_size,                          /*sb_size               */
    H5FD_silo_sb_encode,                        /*sb_encode             */
    H5FD_silo_sb_decode,                        /*sb_decode             */
    0, 						/*fapl_size		*/
    NULL,					/*fapl_get		*/
    NULL,					/*fapl_copy		*/
    NULL, 					/*fapl_free		*/
    0,						/*dxpl_size		*/
    NULL,					/*dxpl_copy		*/
    NULL,					/*dxpl_free		*/
    H5FD_silo_open,		                /*open			*/
    H5FD_silo_close,		                /*close			*/
    H5FD_silo_cmp,			        /*cmp			*/
    H5FD_silo_query,		                /*query			*/
    NULL,					/*get_type_map		*/
    NULL,					/*alloc			*/
    NULL,					/*free			*/
    H5FD_silo_get_eoa,		                /*get_eoa		*/
    H5FD_silo_set_eoa, 	                	/*set_eoa		*/
    H5FD_silo_get_eof,		                /*get_eof		*/
    H5FD_silo_get_handle,                       /*get_handle            */
    H5FD_silo_read,		                /*read			*/
    H5FD_silo_write,		                /*write			*/
    NULL,		                	/*flush			*/
    H5FD_silo_truncate,				/*truncate		*/
    NULL,                                       /*lock                  */
    NULL,                                       /*unlock                */
    H5FD_FLMAP_SINGLE				/*fl_map		*/
};

#ifdef _WIN32
static int my_sopen_s(const char *name, int flags, mode_t mode)
{
    int fd;
    errno_t r = _sopen_s(&fd, name, flags, _SH_DENYNO, mode);
    if (r != 0) fd = -1;
    return fd;
}
#endif

static void update_hotblock_stats(H5FD_silo_t *file, hsize_t id, int dir, float raw_frac)
{
    int bot = 0, top = file->stats.num_hot_blocks - 1, mid=-1;
    silo_vfd_hot_block_stats_t *hbl = file->stats.hot_block_list;
    int haveIt = 0;

    while (bot <= top)
    {
        mid = (bot + top) >> 1;
        if (id > hbl[mid].id)
	{
            if (mid == file->stats.num_hot_blocks-1) break;
            if (id < hbl[mid+1].id) break;
            bot = mid + 1;
	}
        else if (id < hbl[mid].id)
	{
            if (mid == 0 || id > hbl[mid-1].id) {mid--; break; }
            top = mid - 1;
	}
        else
        {
            haveIt = 1;
            break;
        }
    }

    if (!haveIt)
    {
        int i;
        if (file->stats.num_hot_blocks == file->stats.max_hot_blocks)
        {
            int new_max = file->stats.max_hot_blocks * 2 + 1;
            hbl = (silo_vfd_hot_block_stats_t *)realloc(file->stats.hot_block_list, sizeof(silo_vfd_hot_block_stats_t)*new_max);
            file->stats.max_hot_blocks = new_max;
            file->stats.hot_block_list = hbl;
        }
        mid++;
        for (i = file->stats.num_hot_blocks; i > mid; i--)
            hbl[i] = hbl[i-1];
        memset(&hbl[mid], 0, sizeof(silo_vfd_hot_block_stats_t));
        file->stats.num_hot_blocks++;
        hbl[mid].id = id;
    }

    HDassert(id == hbl[mid].id);

    if (dir == OP_WRITE)
    {
        hbl[mid].num_block_writes++;
        if (raw_frac>0.5)
            file->stats.total_block_raw_re_writes++;
        else
            file->stats.total_block_md_re_writes++;
    }
    else
    {
        hbl[mid].num_block_reads++;
        file->stats.total_block_re_reads++;
    }
    hbl[mid].raw_frac = raw_frac;
}

static void set_block_bitmap_by_id(silo_vfd_block_bitmap_t *bbm, hsize_t id)
{
    hsize_t byte_offset = id / (hsize_t) 8;
    int bit_offset = id % (hsize_t) 8;
    int mask = 1<<bit_offset;
    if (byte_offset >= bbm->nbytes)
    {
        bbm->bitmap = (unsigned char *) realloc(bbm->bitmap, (byte_offset+1)*2);
        memset(bbm->bitmap+bbm->nbytes, 0, (byte_offset+1)*2 - bbm->nbytes);
        bbm->nbytes = (byte_offset+1)*2;
    }
    bbm->bitmap[byte_offset] |= mask;
}

static int get_block_bitmap_by_id(silo_vfd_block_bitmap_t *bbm, hsize_t id)
{
    hsize_t byte_offset = id / (hsize_t) 8;
    int bit_offset = id % (hsize_t) 8;
    if (byte_offset < bbm->nbytes)
    {
        int mask = 1<<bit_offset;
        unsigned int val = (unsigned int) bbm->bitmap[byte_offset];
        return val & mask;
    }
    return 0;
}

static silo_vfd_relevant_blocks_t
relevant_blocks(hsize_t block_size, haddr_t addr, hsize_t size)
{
    silo_vfd_relevant_blocks_t ret_value;

    /* first address of first block, inclusive */
    ret_value.id0 = addr / block_size;
    ret_value.off0 = addr % block_size;

    /* last address of last block, inclusive */
    ret_value.id1 = (addr + size - 1) / block_size;
    ret_value.off1 = (addr + size - 1) % block_size;

    return(ret_value);
}

static int find_block_by_id(H5FD_silo_t *file, hsize_t id, unsigned leq)
{
    int bot = 0, top = file->num_blocks - 1, mid;
    silo_vfd_block_t *bl = file->block_list;
    while (bot <= top)
    {
        mid = (bot + top) >> 1;

        if (id > bl[mid].id)
	{
            if (leq)
            {
                if (mid == file->num_blocks-1) return mid;
                if (id < bl[mid+1].id) return mid;
            }
            bot = mid + 1;
	}
        else if (id < bl[mid].id)
	{
            if (leq)
            {
                if (mid == 0) return -1;
                if (id > bl[mid-1].id) return mid-1;
            }
            top = mid - 1;
	}
        else
            return mid;
    }
    return -1; 
}

static int find_block_to_preempt(H5FD_silo_t *file)
{
    int i;
    int min_midx = -1;
    int min_ridx = -1;
    silo_vfd_block_t *bl = file->block_list;
    hsize_t min_mage = file->op_counter;
    hsize_t min_rage = file->op_counter;
    for (i = 1; i < file->num_blocks; i++)
    {
#if 1
        int msize = bl[i].maxmoff - bl[i].minmoff;
        int rsize = bl[i].maxroff - bl[i].minroff;

        if (msize > rsize)
        {
            if (bl[i].age < min_mage)
            {
                min_mage = bl[i].age;
                min_midx = i;
            }
        }
        else
        {
            if (bl[i].age < min_rage)
            {
                min_rage = bl[i].age;
                min_ridx = i;
            }
        }
#else
        if (bl[i].age < min_rage)
        {
            min_rage = bl[i].age;
            min_ridx = i;
        }
#endif
    }

    if (min_ridx == -1)
        return min_midx;
    return min_ridx;
}

static herr_t put_data_to_block_by_index(H5FD_silo_t *file, H5FD_mem_t type, const void *srcbuf, hsize_t size,
    int blidx, int off)
{
    silo_vfd_block_t *block;
    haddr_t addr;

    HDassert(blidx < file->num_blocks);
    block = &(file->block_list[blidx]);

    HDassert(block->buf);

    HDassert((hsize_t)off+size<=file->block_size);
    memcpy((char*)block->buf+off, srcbuf, size);

    block->dirty = 1;
    block->age = file->op_counter++;

    if (type == H5FD_MEM_DRAW)
    {
        if (off < block->minroff) block->minroff = off;
        if (off+size-1 > block->maxroff) block->maxroff = off+size-1;
    }
    else
    {
        if (off < block->minmoff) block->minmoff = off;
        if (off+size-1 > block->maxmoff) block->maxmoff = off+size-1;
    }

    addr = block->id * file->block_size + off + size;
    if (addr > file->eof) file->eof = addr;

    return 0;
}

static herr_t get_data_from_block_by_index(H5FD_silo_t *file, H5FD_mem_t type, void *dstbuf, hsize_t size,
    int blidx, int off)
{
    silo_vfd_block_t *block;

    HDassert(blidx < file->num_blocks);
    block = &(file->block_list[blidx]);

    HDassert(block->buf);
    
    HDassert((hsize_t)off+size<=file->block_size);
    memcpy(dstbuf, (char*)block->buf+off, size);

    block->age = file->op_counter++;

    if (type == H5FD_MEM_DRAW)
    {
        if (off < block->minroff) block->minroff = off;
        if (off+size-1 > block->maxroff) block->maxroff = off+size-1;
    }
    else
    {
        if (off < block->minmoff) block->minmoff = off;
        if (off+size-1 > block->maxmoff) block->maxmoff = off+size-1;
    }

    return 0;
}

static herr_t file_write(H5FD_silo_t *file, haddr_t addr, size_t size, const void *buf)
{
    static const char  *func = "file_write";
    ssize_t		nbytes;
    herr_t              ret_value = 0;

    HDassert(file && file->pub.cls);
    HDassert(buf);

    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow conditions */
    if (HADDR_UNDEF==addr)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "addr undefined", -1, -1)
    if (REGION_OVERFLOW(addr, size))
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "addr overflow", -1, -1)

    /* Seek to the correct location */
    if (addr != file->pos || OP_WRITE != file->op)
    {
        if (HDlseek(file->fd, (file_offset_t)addr, SEEK_SET) < 0)
            H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "HDlseek failed", -1, errno)
        file->stats.total_seeks++;
    }

    /* Write data, being careful of interrupted system calls and partial results */
    while(size > 0) {
        do {
            nbytes = HDwrite(file->fd, buf, size);
            file->stats.total_write_count++;
            file->stats.total_write_bytes += nbytes;
        } while(-1 == nbytes && EINTR == errno);
        if(-1 == nbytes) /* error */
            H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "HDwrite failed", -1, errno)
        HDassert(nbytes > 0);
        HDassert((size_t)nbytes <= size);
        H5_CHECK_OVERFLOW(nbytes, ssize_t, size_t);
        size -= (size_t)nbytes;
        H5_CHECK_OVERFLOW(nbytes, ssize_t, haddr_t);
        addr += (haddr_t)nbytes;
        buf = (const char *)buf + nbytes;
    }

    if (ret_value < 0)
    {
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    }
    else
    {
        file->pos = addr;
        file->op = OP_WRITE;
        if (file->pos > file->file_eof)
            file->file_eof = file->pos;
    }

    return(ret_value);
}

static herr_t file_read(H5FD_silo_t *file, haddr_t addr, size_t size, void *buf)
{
    static const char  *func = "file_read";
    ssize_t		nbytes;
    herr_t              ret_value = 0;

    HDassert(file && file->pub.cls);
    HDassert(buf);

    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow conditions */
    if (HADDR_UNDEF==addr)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "addr undefined", -1, -1)
    if (REGION_OVERFLOW(addr, size))
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "addr overflow", -1, -1)

    /* Seek to the correct location */
    if (addr != file->pos || OP_READ != file->op)
    {
        if (HDlseek(file->fd, (file_offset_t)addr, SEEK_SET) < 0)
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "HDlseek failed", -1, errno)
        file->stats.total_seeks++;
    }

    /* Read data, careful of interrupted system calls, partial results and eof */
    while(size > 0) {
        do {
            nbytes = HDread(file->fd, buf, size);
            file->stats.total_read_count++;
            file->stats.total_read_bytes += nbytes;
        } while(-1 == nbytes && EINTR == errno);
        if(-1 == nbytes) /* error */
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_READERROR, "HDread failed", -1, errno)
        if(0 == nbytes) {
            /* end of file but not end of format address space */
            HDmemset(buf, 0, size);
            break;
        } /* end if */
        HDassert(nbytes >= 0);
        HDassert((size_t)nbytes <= size);
        H5_CHECK_OVERFLOW(nbytes, ssize_t, size_t);
        size -= (size_t)nbytes;
        H5_CHECK_OVERFLOW(nbytes, ssize_t, haddr_t);
        addr += (haddr_t)nbytes;
        buf = (char *)buf + nbytes;
    }

    if (ret_value < 0)
    {
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    }
    else
    {
        file->pos = addr;
        file->op = OP_READ;
    }

    return(ret_value);
}

static herr_t file_write_block(H5FD_silo_t *file, int blidx)
{
    static const char  *func = "file_write_block";
    silo_vfd_block_t *b = &(file->block_list[blidx]);
    herr_t ret_value = 0;
    haddr_t addr;

    HDassert(b->dirty);
    HDassert(b->buf);

    H5Eclear2(H5E_DEFAULT);

    addr = b->id * file->block_size;

    if (file_write(file, addr, file->block_size, b->buf) < 0)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "file_write_block failed", -1, -1)

    if (file->log_stats)
    {
        int msize = 0, rsize = 0;
        if (b->maxmoff > b->minmoff)
            msize = b->maxmoff - b->minmoff;
        if (b->maxroff > b->minroff)
            rsize = b->maxroff - b->minroff;

        if (rsize >= msize)
            file->stats.total_block_raw_writes++;
        else
            file->stats.total_block_md_writes++;

        if (get_block_bitmap_by_id(&(file->was_written_map), b->id))
            update_hotblock_stats(file, b->id, OP_WRITE, (rsize+msize)?(float)rsize/(msize+rsize):(float)0);

        set_block_bitmap_by_id(&(file->was_written_map), b->id);
    }

    if (ret_value == 0)
        b->dirty = 0;

    return(ret_value);
}

static herr_t file_read_block(H5FD_silo_t *file, int blidx)
{
    static const char  *func = "file_read_block";
    silo_vfd_block_t *b = &(file->block_list[blidx]);
    herr_t ret_value = 0;
    haddr_t addr;

    H5Eclear2(H5E_DEFAULT);

    addr = b->id * file->block_size;

    if (file_read(file, addr, file->block_size, b->buf) < 0)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_READERROR, "file_read_block failed", -1, -1)
    file->stats.total_block_reads++;

    /* check if the block was ever in memory before */
    if (file->log_stats)
    {
        if (get_block_bitmap_by_id(&(file->was_in_mem_map), b->id))
            update_hotblock_stats(file, b->id, OP_READ, 0);
    }

    if (ret_value == 0)
        b->dirty = 0;

    return(ret_value);
}

static herr_t remove_block_by_index(H5FD_silo_t *file, int blidx)
{
    int i;
    silo_vfd_block_t *bl = file->block_list;
    silo_vfd_block_t *b = &file->block_list[blidx];

    HDassert(file->num_blocks>0);

    if (file->log_stats)
    {
        int msize = b->maxmoff - b->minmoff;
        int rsize = b->maxroff - b->minroff;

        if (rsize >= msize)
            file->stats.num_blocks_majority_raw++;
        else
            file->stats.num_blocks_majority_md++;
    }

    for (i = blidx; i < file->num_blocks-1; i++)
        bl[i] = bl[i+1];

    file->num_blocks--;

    return 0;
}

/* blidx refers to the block in the list JUST BEFORE the block we're inserting */ 
/* a -1 implies it comes JUST BEFORE the 0th block */
static herr_t insert_block_by_index(H5FD_silo_t *file, int blidx)
{
    int i;
    silo_vfd_block_t *bl = file->block_list;

    HDassert(file->num_blocks<file->max_blocks);

    for (i = file->num_blocks; i > blidx+1; i--)
        bl[i] = bl[i-1];
    memset(&bl[blidx+1], 0, sizeof(silo_vfd_block_t));

    file->num_blocks++;

    if (file->log_stats)
    {
        if (file->num_blocks > file->stats.max_blocks_in_mem)
            file->stats.max_blocks_in_mem = file->num_blocks;
    }

    return 0;
}

static int alloc_block_by_id(H5FD_silo_t *file, hsize_t id)
{
    haddr_t addr0 = id * file->block_size;
    silo_vfd_block_t *b;
    int blidx = find_block_by_id(file, id, CLOSEST);

    /* blidx refers to the block in the list JUST BEFORE the block we're inserting */ 
    insert_block_by_index(file, blidx);

    /* update blidx to point to the block we're inserting */
    blidx++;

    b = &(file->block_list[blidx]);

    b->buf = malloc(file->block_size);
    HDassert(b->buf);
    b->id = id;
    b->age = file->op_counter++;
    b->minmoff = file->block_size;
    b->maxmoff = 0;
    b->minroff = file->block_size;
    b->maxroff = 0;

    if (addr0<file->file_eof)
        file_read_block(file, blidx);

    if (file->log_stats)
    {
        set_block_bitmap_by_id(&(file->was_in_mem_map), id);
        if (id > file->stats.max_block_id) file->stats.max_block_id = id;
    }

    return blidx;
}

static herr_t free_block_by_index(H5FD_silo_t *file, int blidx)
{
    silo_vfd_block_t *b;
    
    HDassert(blidx<file->num_blocks);

    b = &(file->block_list[blidx]);

    HDassert(b->buf);

    if (b->dirty)
        file_write_block(file, blidx);

    free(b->buf);

    remove_block_by_index(file, blidx);

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_init
 *
 * Purpose:	Initialize this driver by registering the driver with the
 *		library.
 *
 * Return:	Success:	The driver ID for the silo driver.
 *
 *		Failure:	Negative.
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *      Stolen from the sec2 driver - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_silo_init(void)
{
    static const char *func="H5FD_silo_init";

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if (H5I_VFL!=H5Iget_type(H5FD_SILO_g))
        H5FD_SILO_g = H5FDregister(&H5FD_silo_g);

    return(H5FD_SILO_g);
}

/*---------------------------------------------------------------------------
 * Function:	H5FD_silo_term
 *
 * Purpose:	Shut down the VFD
 *
 * Return:	<none>
 *
 * Programmer:  Quincey Koziol
 *              Friday, Jan 30, 2004
 *
 * Modification:
 *
 *---------------------------------------------------------------------------
 */
void
H5FD_silo_term(void)
{
    /* Reset VFL ID */
    H5FD_SILO_g=0;

} /* end H5FD_silo_term() */

/*-------------------------------------------------------------------------
 * Function:	H5Pset_fapl_silo
 *
 * Purpose:	Modify the file access property list to use the H5FD_SILO
 *		driver defined in this source file.  There are no driver
 *		specific properties.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Thursday, February 19, 1998
 *
 * Modifications:
 *      Stolen from the sec2 driver - QAK, 10/18/99
 *      Ditto, Mark C. Miller, Febuary, 2010
 *
 *   Mark C. Miller, Wed Jul 14 20:59:15 PDT 2010
 *   Added support for direct I/O option. Made default values macro
 *   constants.
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_fapl_silo(hid_t fapl_id)
{
    static const char *func = "H5FDset_fapl_silo"; 
    herr_t ret_value = 0;
    hsize_t default_block_size = H5FD_SILO_DEFAULT_BLOCK_SIZE;
    int default_block_count = H5FD_SILO_DEFAULT_BLOCK_COUNT;
    int default_log_stats = H5FD_SILO_DEFAULT_LOG_STATS;
    int default_use_direct = H5FD_SILO_DEFAULT_USE_DIRECT;

    H5Eclear2(H5E_DEFAULT);

    if(0 == H5Pisa_class(fapl_id, H5P_FILE_ACCESS))
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1, -1)

    if (H5Pinsert(fapl_id, SILO_BLKSZ_PROPNAME, sizeof(hsize_t), &default_block_size, 0, 0, 0, 0, 0) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTINSERT, "can't insert " SILO_BLKSZ_PROPNAME, -1, -1)
    if (H5Pinsert(fapl_id, SILO_BLKCNT_PROPNAME, sizeof(int), &default_block_count, 0, 0, 0, 0, 0) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTINSERT, "can't insert " SILO_BLKCNT_PROPNAME, -1, -1)
    if (H5Pinsert(fapl_id, SILO_LOGSTS_PROPNAME, sizeof(int), &default_log_stats, 0, 0, 0, 0, 0) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTINSERT, "can't insert " SILO_LOGSTS_PROPNAME, -1, -1)
    if (H5Pinsert(fapl_id, SILO_USEDIR_PROPNAME, sizeof(int), &default_use_direct, 0, 0, 0, 0, 0) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTINSERT, "can't insert " SILO_USEDIR_PROPNAME, -1, -1)

    if (H5Pset(fapl_id, SILO_BLKSZ_PROPNAME, &default_block_size) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set " SILO_BLKSZ_PROPNAME, -1, -1)
    if (H5Pset(fapl_id, SILO_BLKCNT_PROPNAME, &default_block_count) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set " SILO_BLKCNT_PROPNAME, -1, -1)
    if (H5Pset(fapl_id, SILO_LOGSTS_PROPNAME, &default_log_stats) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set " SILO_LOGSTS_PROPNAME, -1, -1)
    if (H5Pset(fapl_id, SILO_USEDIR_PROPNAME, &default_use_direct) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set " SILO_USEDIR_PROPNAME, -1, -1)

    return H5Pset_driver(fapl_id, H5FD_SILO, NULL);
}

herr_t
H5Pset_silo_block_size_and_count(hid_t fapl_id, hsize_t block_size, int max_blocks_in_mem)
{
    static const char *func="H5FDset_silo_block_size_and_count";
    herr_t ret_value = 0;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if(0 == H5Pisa_class(fapl_id, H5P_FILE_ACCESS))
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1, -1)
    if (H5Pset(fapl_id, SILO_BLKSZ_PROPNAME, &block_size) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set silo_block_size", -1, -1)
    if (H5Pset(fapl_id, SILO_BLKCNT_PROPNAME, &max_blocks_in_mem) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set silo_block_count", -1, -1)

    return ret_value;
}

herr_t
H5Pset_silo_log_stats(hid_t fapl_id, int log)
{
    static const char *func="H5Pset_silo_log_stats";
    herr_t ret_value = 0;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if(0 == H5Pisa_class(fapl_id, H5P_FILE_ACCESS))
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1, -1)
    if (H5Pset(fapl_id, SILO_LOGSTS_PROPNAME, &log) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set silo_log_stats", -1, -1)

    return ret_value;
}

herr_t
H5Pset_silo_use_direct(hid_t fapl_id, int used)
{
    static const char *func="H5Pset_silo_use_direct";
    herr_t ret_value = 0;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if(0 == H5Pisa_class(fapl_id, H5P_FILE_ACCESS))
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1, -1)
    if (H5Pset(fapl_id, SILO_USEDIR_PROPNAME, &used) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTSET, "can't set " SILO_USEDIR_PROPNAME, -1, -1)

    return ret_value;
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_sb_size
 *
 * Purpose:	Returns the size of the private information to be stored in
 *		the superblock.
 *
 * Return:	Success:	The super block driver data size.
 *
 *		Failure:	never fails
 *
 * Programmer:	Robb Matzke
 *              Monday, August 16, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static hsize_t
H5FD_silo_sb_size(H5FD_t *_file)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;
    unsigned		nseen = 0;
    hsize_t		nbytes = 8; /*size of "LLNLsilo" header*/

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* block size for file */
    nbytes += 8;

/*    return 1024-100-nbytes;*/
    return nbytes;
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_sb_encode
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_sb_encode(H5FD_t *_file, char *name/*out*/,
		     unsigned char *buf/*out*/)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;
    unsigned char	*p;
    static const char *func = "H5FD_silo_sb_encode";

    H5Eclear2(H5E_DEFAULT);

    /* Name and version number */
    strncpy(name, "LLNLsilo", (size_t)8);
    name[8] = '\0';

    /* Encode block size into sb */
    p = buf+8;
    assert(sizeof(hsize_t)<=8);
    memcpy(p, &file->block_size, sizeof(hsize_t));
    if (H5Tconvert(H5T_NATIVE_HSIZE, H5T_STD_U64LE, 1, buf+8, NULL, H5P_DEFAULT)<0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_DATATYPE, H5E_CANTCONVERT, "can't convert superblock info", -1)

    return 0;
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_sb_decode
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_sb_decode(H5FD_t *_file, const char *name, const unsigned char *buf)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;
    char	       x[8];
    hsize_t           *ap;
    static const char *func = "H5FD_silo_sb_decode";

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Make sure the name/version number is correct */
    if (strcmp(name, "LLNLsilo"))
        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_BADVALUE, "invalid silo superblock", -1)

    buf += 8;
    /* Decode block size */
    assert(sizeof(hsize_t)<=8);
    memcpy(x, buf, 8);
    if (H5Tconvert(H5T_STD_U64LE, H5T_NATIVE_HSIZE, 1, x, NULL, H5P_DEFAULT)<0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_DATATYPE, H5E_CANTCONVERT, "can't convert superblock info", -1)
    ap = (hsize_t*)x;
    /*file->block_size = *ap; ignore stored value for now */

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_open
 *
 * Purpose:	Create and/or opens a Standard C file as an HDF5 file.
 *
 * Bugs:	H5F_ACC_EXCL has a race condition. (? -QAK)
 *
 * Errors:
 *		IO	  CANTOPENFILE	File doesn't exist and CREAT wasn't
 *					specified.
 *		IO	  CANTOPENFILE	Fopen failed.
 *		IO	  FILEEXISTS	File exists but CREAT and EXCL were
 *					specified.
 *
 * Return:	Success:	A pointer to a new file data structure. The
 *				public fields will be initialized by the
 *				caller, which is always H5FD_open().
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *		Wednesday, October 22, 1997
 *
 * Modifications:
 *      Ported to VFL/H5FD layer - QAK, 10/18/99
 *
 *   Mark C. Miller, Wed Jul 14 21:00:13 PDT 2010
 *   Added direct I/O flag.
 *
 *   Kathleen Bonnell, Thu Jul 29 09:52:10 PDT 2010
 *   Added mode ivar so that correct mode setting could be set for Windows.
 *-------------------------------------------------------------------------
 */
static H5FD_t *
H5FD_silo_open( const char *name, unsigned flags, hid_t fapl_id,
    haddr_t maxaddr)
{
    int         o_flags;
    int         fd = -1;
    unsigned    write_access = 0;     /* File opened with write access? */
    H5FD_silo_t	*file = NULL;
    h5_stat_t   sb;
    static const char *func = "H5FD_silo_open";  /* Function Name for error reporting */
    int silo_block_count = H5FD_SILO_DEFAULT_BLOCK_COUNT;
    hsize_t silo_block_size = H5FD_SILO_DEFAULT_BLOCK_SIZE;
    int     silo_log_stats = H5FD_SILO_DEFAULT_LOG_STATS;
    int     silo_use_direct = H5FD_SILO_DEFAULT_USE_DIRECT;
    H5FD_t *ret_value = 0;
    mode_t mode;

    /* Sanity check on file offsets */
    assert(sizeof(file_offset_t)>=sizeof(size_t));

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check arguments */
    if (!name || !*name)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADVALUE, "invalid file name", NULL, -1)
    if (0==maxaddr || HADDR_UNDEF==maxaddr)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADRANGE, "bogus maxaddr", NULL, -1)
    if (ADDR_OVERFLOW(maxaddr))
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_ARGS, H5E_OVERFLOW, "maxaddr too large", NULL, -1)

    /* get some properties and sanity check them */
    if (H5Pget(fapl_id, SILO_BLKSZ_PROPNAME, &silo_block_size) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTGET, "can't get " SILO_BLKSZ_PROPNAME, 0, -1)

    if (H5Pget(fapl_id, SILO_BLKCNT_PROPNAME, &silo_block_count) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTGET, "can't get " SILO_BLKCNT_PROPNAME, 0, -1)
    if (silo_block_count < 1)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTGET, "silo_block_count<1", 0, -1)

    if (H5Pget(fapl_id, SILO_LOGSTS_PROPNAME, &silo_log_stats) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTGET, "can't get " SILO_LOGSTS_PROPNAME, 0, -1)
    if (H5Pget(fapl_id, SILO_USEDIR_PROPNAME, &silo_use_direct) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_PLIST, H5E_CANTGET, "can't get " SILO_USEDIR_PROPNAME, 0, -1)

    /* Build the open flags */
    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
    if (H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
    if (H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
    if (H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
#ifdef O_DIRECT
    if (silo_use_direct) o_flags |= O_DIRECT;
#endif
#ifdef _WIN32
    mode = _S_IWRITE | _S_IREAD;
#else
    mode = 0666;
#endif

    errno = 0;
    if ((fd = HDopen(name, o_flags, mode)) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_CANTOPENFILE, "HDopen failed", NULL, errno)

    if (HDfstat(fd, &sb)<0)
    {
        close(fd);
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_FILE, H5E_BADFILE, "HDfstat failed", NULL, errno)
    }

    if (flags & H5F_ACC_RDWR)
        write_access = 1;

    /* Build the return value */
    if(NULL == (file = (H5FD_silo_t *)calloc((size_t)1, sizeof(H5FD_silo_t))))
    {
        close(fd);
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_RESOURCE, H5E_NOSPACE, "calloc failed", NULL, errno)
    }
    if(NULL == (file->block_list = (silo_vfd_block_t *)calloc((size_t)silo_block_count, sizeof(silo_vfd_block_t))))
    {
        close(fd);
        free(file);
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_RESOURCE, H5E_NOSPACE, "calloc failed", NULL, errno)
    }

    file->fd = fd;
    file->file_eof = (haddr_t)sb.st_size;
    file->eof = (haddr_t)sb.st_size;
    file->pos = HADDR_UNDEF;
    file->op = OP_UNKNOWN;
    file->write_access = write_access;
    file->block_size = silo_block_size;
    file->max_blocks = silo_block_count;
    file->log_stats = silo_log_stats;
    if (silo_log_stats)
    {
        const char *ext = "-h5-vfd-log";
        if (NULL == (file->log_name = (char*) malloc(strlen(name)+strlen(ext)+1)))
        {
            close(file->fd);
            free(file->block_list);
            free(file);
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_RESOURCE, H5E_NOSPACE, "malloc failed", NULL, errno)
        }
        sprintf(file->log_name, "%s%s", name, ext);
    }

    /* The unique key */
    {
#ifdef _WIN32
	struct _BY_HANDLE_FILE_INFORMATION fileinfo;
        (void)GetFileInformationByHandle((HANDLE)_get_osfhandle(file->fd), &fileinfo);
        file->fileindexhi = fileinfo.nFileIndexHigh;
        file->fileindexlo = fileinfo.nFileIndexLow;
#else
        file->device = sb.st_dev;
#ifdef H5_VMS
        file->inode[0] = sb.st_ino[0];
        file->inode[1] = sb.st_ino[1];
        file->inode[2] = sb.st_ino[2];
#else
        file->inode = sb.st_ino;
#endif /*H5_VMS*/

#endif
    }

    return((H5FD_t*)file);
}   /* end H5FD_silo_open() */

/*-------------------------------------------------------------------------
 * Function:	H5F_silo_close
 *
 * Purpose:	Closes a file.
 *
 * Errors:
 *		IO	  CLOSEERROR	Fclose failed.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Wednesday, October 22, 1997
 *
 * Modifications:
 *      Ported to VFL/H5FD layer - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_close(H5FD_t *_file)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;
    static const char *func="H5FD_silo_close";  /* Function Name for error reporting */
    herr_t ret_value = 0;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* write any dirty blocks to file */
    if (file->write_access)
    {
        int i;

        /* sort blocks by increasing block id */
        silo_vfd_pair_t *sorted_pairs = (silo_vfd_pair_t*) malloc(file->num_blocks*sizeof(silo_vfd_pair_t));
        for (i = 0; i < file->num_blocks; i++)
        {
            sorted_pairs[i].i = i;
            sorted_pairs[i].id = file->block_list[i].id; 
        }
        qsort(sorted_pairs, file->num_blocks, sizeof(silo_vfd_pair_t), compare_silo_vfd_pairs);

        /* write the blocks, freeing as we go along */
        for (i = 0; i < file->num_blocks; i++)
        {
            silo_vfd_block_t *b = &(file->block_list[sorted_pairs[i].i]);
            if (!(b->buf)) continue;
            if (b->dirty) file_write_block(file, sorted_pairs[i].i);
            free(b->buf);
        }
        free(sorted_pairs);
    }

    errno = 0;
    if (close(file->fd) < 0)
        H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_CLOSEERROR, "close failed", -1, errno)

    if (file->log_stats)
    {
        int i, first;
        hsize_t cum_raw_count, cum_raw_bytes, cum_md_count, cum_md_bytes;
        hsize_t tot_raw_count, tot_raw_bytes, tot_md_count, tot_md_bytes;
        FILE* logf = fopen(file->log_name, "w");
        fprintf(logf, "======== Interactions between the VFD and the filesystem ========\n");
        fprintf(logf, "block size = %llu\n", file->block_size);
        fprintf(logf, "block count = %d\n", file->max_blocks);
        fprintf(logf, "\n");
        fprintf(logf, "max block id = %llu\n", file->stats.max_block_id);
        fprintf(logf, "max blocks in mem = %llu\n", file->stats.max_blocks_in_mem);
        fprintf(logf, "\n");
        fprintf(logf, "total seeks = %llu\n", file->stats.total_seeks);
        fprintf(logf, "\n");
        fprintf(logf, "number of multi-block writes = %llu\n", file->stats.num_multiblock_writes);
        fprintf(logf, "number of multi-block reads = %llu\n", file->stats.num_multiblock_reads);
        fprintf(logf, "\n");
        fprintf(logf, "number of blocks majority md = %llu\n", file->stats.num_blocks_majority_md);
        fprintf(logf, "number of blocks majority raw = %llu\n", file->stats.num_blocks_majority_raw);
        fprintf(logf, "\n");
        fprintf(logf, "number of writes = %llu\n", file->stats.total_write_count);
        fprintf(logf, "number of bytes written = %llu\n", file->stats.total_write_bytes);
        fprintf(logf, "\n");
        fprintf(logf, "number of times a raw block was written = %llu\n", file->stats.total_block_raw_writes);
        fprintf(logf, "number of times a raw block was written more than once = %llu\n", file->stats.total_block_raw_re_writes);
        fprintf(logf, "\n");
        fprintf(logf, "number of times an md block was written = %llu\n", file->stats.total_block_md_writes);
        fprintf(logf, "number of times an md block was written more than once = %llu\n", file->stats.total_block_md_re_writes);
        fprintf(logf, "\n");
        fprintf(logf, "number of reads = %llu\n", file->stats.total_read_count);
        fprintf(logf, "number of bytes read = %llu\n", file->stats.total_read_bytes);
        fprintf(logf, "\n");
        fprintf(logf, "number of times a block was read = %llu\n", file->stats.total_block_reads);
        fprintf(logf, "number of times a block was read more than once = %llu\n", file->stats.total_block_re_reads);
        fprintf(logf, "\n");
        fprintf(logf, "number of hot blocks %d\n", file->stats.num_hot_blocks);
        fprintf(logf, "hot blocks...\n");
        for (i = 0; i < file->stats.num_hot_blocks; i++)
        {
            silo_vfd_hot_block_stats_t *hb = &(file->stats.hot_block_list[i]); 
            fprintf(logf,"    %8llu: %4s (%f), #writes=%8llu, #reads=%8llu\n",
                hb->id, (hb->raw_frac>0.5?"raw":"meta"), hb->raw_frac, hb->num_block_writes+1, hb->num_block_reads+1);
        }
        if (file->stats.hot_block_list) free(file->stats.hot_block_list);
        if (file->was_written_map.bitmap) free(file->was_written_map.bitmap);
        if (file->was_in_mem_map.bitmap) free(file->was_in_mem_map.bitmap);
        fprintf(logf, "\n");
        fprintf(logf, "\n");
        fprintf(logf, "\n");
        fprintf(logf, "======== Interactions between HDF5 library and the VFD ========\n");
        fprintf(logf, "number raw writes = %llu\n", file->stats.total_vfd_raw_write_count);
        fprintf(logf, "number raw bytes written = %llu\n", file->stats.total_vfd_raw_write_bytes);
        fprintf(logf, "number md writes = %llu\n", file->stats.total_vfd_md_write_count);
        fprintf(logf, "number md bytes written = %llu\n", file->stats.total_vfd_md_write_bytes);
        fprintf(logf, "histogram...\n");
        cum_raw_count = 0;
        cum_raw_bytes = 0;
        cum_md_count = 0;
        cum_md_bytes = 0;
        tot_raw_count = file->stats.total_vfd_raw_write_count;
        if (tot_raw_count < 1) tot_raw_count = 1;
        tot_raw_bytes = file->stats.total_vfd_raw_write_bytes;
        if (tot_raw_bytes < 1) tot_raw_bytes = 1;
        tot_md_count = file->stats.total_vfd_md_write_count;
        if (tot_md_count < 1) tot_md_count = 1;
        tot_md_bytes = file->stats.total_vfd_md_write_bytes;
        if (tot_md_bytes < 1) tot_md_bytes = 1;
        for (i = 0, first = 1; i < 32; i++)
        {
            cum_raw_count += file->stats.vfd_raw_write_count_hist[i];
            cum_raw_bytes += file->stats.vfd_raw_write_bytes_hist[i];
            cum_md_count += file->stats.vfd_md_write_count_hist[i];
            cum_md_bytes += file->stats.vfd_md_write_bytes_hist[i];

            if (file->stats.vfd_raw_write_count_hist[i] == 0 &&
                file->stats.vfd_md_write_count_hist[i] == 0)
                continue;

            if (first)
            {
                first = 0;
                fprintf(logf,"                                              WRITES                                        \n");
                fprintf(logf,"------------------------------------------------|-------------------------------------------\n");
                fprintf(logf,"                    RAW DATA                    |                   META DATA               \n");
                fprintf(logf,"    #reqs      Tot   Cum  #byts      Tot   Cum  | #reqs      Tot   Cum  #byts      Tot   Cum\n");
            }

            fprintf(logf,"%2d: %8llu (%3d%%, %3d%%) %8llu (%3d%%, %3d%%) | "
                              "%8llu (%3d%%, %3d%%) %8llu (%3d%%, %3d%%)\n", i,
                file->stats.vfd_raw_write_count_hist[i],
                (int) (100.0 * file->stats.vfd_raw_write_count_hist[i] / tot_raw_count),
                (int) (100.0 * cum_raw_count / tot_raw_count),
                file->stats.vfd_raw_write_bytes_hist[i],
                (int) (100.0 * file->stats.vfd_raw_write_bytes_hist[i] / tot_raw_bytes),
                (int) (100.0 * cum_raw_bytes / tot_raw_bytes),
                file->stats.vfd_md_write_count_hist[i],
                (int) (100.0 * file->stats.vfd_md_write_count_hist[i] / tot_md_count),
                (int) (100.0 * cum_md_count / tot_md_count),
                file->stats.vfd_md_write_bytes_hist[i],
                (int) (100.0 * file->stats.vfd_md_write_bytes_hist[i] / tot_md_bytes),
                (int) (100.0 * cum_md_bytes / tot_md_bytes));
        }
        cum_raw_count = 0;
        cum_raw_bytes = 0;
        cum_md_count = 0;
        cum_md_bytes = 0;
        tot_raw_count = file->stats.total_vfd_raw_read_count;
        if (tot_raw_count < 1) tot_raw_count = 1;
        tot_raw_bytes = file->stats.total_vfd_raw_read_bytes;
        if (tot_raw_bytes < 1) tot_raw_bytes = 1;
        tot_md_count = file->stats.total_vfd_md_read_count;
        if (tot_md_count < 1) tot_md_count = 1;
        tot_md_bytes = file->stats.total_vfd_md_read_bytes;
        if (tot_md_bytes < 1) tot_md_bytes = 1;
        for (i = 0, first = 1; i < 32; i++)
        {
            cum_raw_count += file->stats.vfd_raw_write_count_hist[i];
            cum_raw_bytes += file->stats.vfd_raw_write_bytes_hist[i];
            cum_md_count += file->stats.vfd_md_write_count_hist[i];
            cum_md_bytes += file->stats.vfd_md_write_bytes_hist[i];

            if (file->stats.vfd_raw_read_count_hist[i] == 0 &&
                file->stats.vfd_md_read_count_hist[i] == 0)
                continue;

            if (first)
            {
                first = 0;
                fprintf(logf,"                                              READS                                         \n");
                fprintf(logf,"------------------------------------------------|-------------------------------------------\n");
                fprintf(logf,"                    RAW DATA                    |                   META DATA               \n");
                fprintf(logf,"    #reqs      Tot   Cum  #byts      Tot   Cum  | #reqs      Tot   Cum  #byts      Tot   Cum\n");
            }

            fprintf(logf,"%2d: %8llu (%3d%%, %3d%%) %8llu (%3d%%, %3d%%) | "
                              "%8llu (%3d%%, %3d%%) %8llu (%3d%%, %3d%%)\n", i,
                file->stats.vfd_raw_read_count_hist[i],
                (int) (100.0 * file->stats.vfd_raw_read_count_hist[i] / tot_raw_count),
                (int) (100.0 * cum_raw_count / tot_raw_count),
                file->stats.vfd_raw_read_bytes_hist[i],
                (int) (100.0 * file->stats.vfd_raw_read_bytes_hist[i] / tot_raw_bytes),
                (int) (100.0 * cum_raw_bytes / tot_raw_bytes),
                file->stats.vfd_md_read_count_hist[i],
                (int) (100.0 * file->stats.vfd_md_read_count_hist[i] / tot_md_count),
                (int) (100.0 * cum_md_count / tot_md_count),
                file->stats.vfd_md_read_bytes_hist[i],
                (int) (100.0 * file->stats.vfd_md_read_bytes_hist[i] / tot_md_bytes),
                (int) (100.0 * cum_md_bytes / tot_md_bytes));
        }

        fclose(logf);
        free(file->log_name);
    }

    free(file->block_list);
    free(file);

    return(0);
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_cmp
 *
 * Purpose:	Compares two files belonging to this driver using an
 *		arbitrary (but consistent) ordering.
 *
 * Return:	Success:	A value like strcmp()
 *
 *		Failure:	never fails (arguments were checked by the
 *				caller).
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *      Stolen from the sec2 driver - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
static int
H5FD_silo_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
{
    const H5FD_silo_t	*f1 = (const H5FD_silo_t*)_f1;
    const H5FD_silo_t	*f2 = (const H5FD_silo_t*)_f2;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

#ifdef _WIN32
    if (f1->fileindexhi < f2->fileindexhi) return -1;
    if (f1->fileindexhi > f2->fileindexhi) return 1;

    if (f1->fileindexlo < f2->fileindexlo) return -1;
    if (f1->fileindexlo > f2->fileindexlo) return 1;

#else
#ifdef H5_DEV_T_IS_SCALAR
    if (f1->device < f2->device) return -1;
    if (f1->device > f2->device) return 1;
#else /* H5_DEV_T_IS_SCALAR */
    /* If dev_t isn't a scalar value on this system, just use memcmp to
     * determine if the values are the same or not.  The actual return value
     * shouldn't really matter...
     */
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) return -1;
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) return 1;
#endif /* H5_DEV_T_IS_SCALAR */

#ifndef H5_VMS
    if (f1->inode < f2->inode) return -1;
    if (f1->inode > f2->inode) return 1;
#else
    if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))<0) return -1;
    if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))>0) return 1;
#endif /*H5_VMS*/

#endif

    return 0;

}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_query
 *
 * Purpose:	Set the flags that this VFL driver is capable of supporting.
 *              (listed in H5FDpublic.h)
 *
 * Return:	Success:	non-negative
 *
 *		Failure:	negative
 *
 * Programmer:	Quincey Koziol
 *              Friday, August 25, 2000
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_query(const H5FD_t *_f, unsigned long *flags /* out */)
{
    /* Shut compiler up */
    _f=_f;

    /* Set the VFL feature flags that this driver supports */
    if(flags) {
        *flags = 0;
        *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
        *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
        *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
    }

    return(0);
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_get_eoa
 *
 * Purpose:	Gets the end-of-address marker for the file. The EOA marker
 *		is the first address past the last byte allocated in the
 *		format address space.
 *
 * Return:	Success:	The end-of-address marker.
 *
 *		Failure:	HADDR_UNDEF
 *
 * Programmer:	Robb Matzke
 *              Monday, August  2, 1999
 *
 * Modifications:
 *              Stolen from the sec2 driver - QAK, 10/18/99
 *
 *              Raymond Lu
 *              21 Dec. 2006
 *              Added the parameter TYPE.  It's only used for MULTI driver.
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_silo_get_eoa(const H5FD_t *_file, H5FD_mem_t /*unused*/ type)
{
    const H5FD_silo_t	*file = (const H5FD_silo_t *)_file;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Shut compiler up */
    type = type;

    return(file->eoa);
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_set_eoa
 *
 * Purpose:	Set the end-of-address marker for the file. This function is
 *		called shortly after an existing HDF5 file is opened in order
 *		to tell the driver where the end of the HDF5 data is located.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *              Stolen from the sec2 driver - QAK, 10/18/99
 *
 *              Raymond Lu
 *              21 Dec. 2006
 *              Added the parameter TYPE.  It's only used for MULTI driver.
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Shut compiler up */
    type = type;

    file->eoa = addr;

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:	H5FD_silo_get_eof
 *
 * Purpose:	Returns the end-of-file marker, which is the greater of
 *		either the Unix end-of-file or the HDF5 end-of-address
 *		markers.
 *
 * Return:	Success:	End of file address, the first address past
 *				the end of the "file", either the Unix file
 *				or the HDF5 file.
 *
 *		Failure:	HADDR_UNDEF
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *      Stolen from the sec2 driver - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
#if HDF5_VERSION_GE(1,10,4)
H5FD_silo_get_eof(const H5FD_t *_file, H5FD_mem_t type)
#else
H5FD_silo_get_eof(const H5FD_t *_file)
#endif
{
#warning TAKE ADVANTAGE OF TYPE INFO HERE
    const H5FD_silo_t	*file = (const H5FD_silo_t *)_file;

    return(MAX(file->eof, file->eoa));
}

/*-------------------------------------------------------------------------
 * Function:       H5FD_silo_get_handle
 *
 * Purpose:        Returns the file handle of silo file driver.
 *
 * Returns:        Non-negative if succeed or negative if fails.
 *
 * Programmer:     Raymond Lu
 *                 Sept. 16, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle)
{
    H5FD_silo_t       *file = (H5FD_silo_t *)_file;
    static const char  *func="H5FD_silo_get_handle";  /* Function Name for error reporting */

    /* Shut compiler up */
    fapl=fapl;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if (file_handle)
        *file_handle = &(file->fd);

    return(0);
}

/*-------------------------------------------------------------------------
 * Function:	H5F_silo_read
 *
 * Purpose:	Reads SIZE bytes beginning at address ADDR in file LF and
 *		places them in buffer BUF.  Reading past the logical or
 *		physical end of file returns zeros instead of failing.
 *
 * Errors:
 *		IO	  READERROR	Fread failed.
 *		IO	  SEEKERROR	Fseek failed.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Wednesday, October 22, 1997
 *
 * Modifications:
 *		June 2, 1998	Albert Cheng
 *		Added xfer_mode argument
 *
 *      Ported to VFL/H5FD layer - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, size_t size,
    void *buf/*out*/)
{
    H5FD_silo_t		*file = (H5FD_silo_t*)_file;
    static const char *func="H5FD_silo_read";  /* Function Name for error reporting */
    herr_t ret_value = 0;
    silo_vfd_block_t *bl;
    silo_vfd_relevant_blocks_t rb;
    hsize_t id, nbytes;
    int blidx, bufoff;

    /* Shut compiler up */
    type=type;
    dxpl_id=dxpl_id;

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow */
    if (HADDR_UNDEF==addr)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)
    if (REGION_OVERFLOW(addr, size))
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)
    if ((addr+size)>file->eoa)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)

    if (size == 0)
        return 0;

    rb = relevant_blocks(file->block_size, addr, size);
    blidx = -1; 
    bl = file->block_list;
    bufoff = 0;
    for (id = rb.id0; id <= rb.id1; id++)
    {
        /* look for the block in the list */
        if (blidx < 0 || blidx >= file->num_blocks-1)
            blidx = find_block_by_id(file, id, EXACT); 
        else if (bl[blidx+1].id != id)
            blidx = find_block_by_id(file, id, EXACT); 
        else
            blidx++;

        if (blidx < 0)
        {
            if (file->num_blocks == file->max_blocks)
            {
                int tmpblidx = find_block_to_preempt(file);
                free_block_by_index(file, tmpblidx);
            }
            blidx = alloc_block_by_id(file, id);
        }

        /* put the data in the block */
	if (id == rb.id0 && id == rb.id1)
	{
	    get_data_from_block_by_index(file, type, buf, size, blidx, rb.off0);
	    bufoff += size;
	}
        else if (id == rb.id0)
	{
	    nbytes = file->block_size - rb.off0;
	    get_data_from_block_by_index(file, type, (char*)buf+bufoff, nbytes, blidx, rb.off0);
	    bufoff += nbytes;
	}
	else if (id == rb.id1)
	{
	    nbytes = rb.off1+1;
	    get_data_from_block_by_index(file, type, (char*)buf+bufoff, nbytes, blidx, 0);
	    bufoff += nbytes;
	}
	else
	{
	    get_data_from_block_by_index(file, type, (char*)buf+bufoff, file->block_size, blidx, 0);
	    bufoff += file->block_size;
	}
    }

    if (file->log_stats)
    {
        int n;
        hsize_t tmpsize = size;
        for (n = 0; tmpsize; n++, tmpsize=(tmpsize>>1));
        if (type == H5FD_MEM_DRAW)
        {
            file->stats.total_vfd_raw_read_count++;
            file->stats.total_vfd_raw_read_bytes += size;
            file->stats.vfd_raw_read_count_hist[n]++;
            file->stats.vfd_raw_read_bytes_hist[n] += size;
        }
        else
        {
            file->stats.total_vfd_md_read_count++;
            file->stats.total_vfd_md_read_bytes += size;
            file->stats.vfd_md_read_count_hist[n]++;
            file->stats.vfd_md_read_bytes_hist[n] += size;
        }
        if (rb.id1 > rb.id0+1)
            file->stats.num_multiblock_reads++;
    }

    return(0);
}

/*-------------------------------------------------------------------------
 * Function:	H5F_silo_write
 *
 * Purpose:	Writes SIZE bytes from the beginning of BUF into file LF at
 *		file address ADDR.
 *
 * Errors:
 *		IO	  SEEKERROR	Fseek failed.
 *		IO	  WRITEERROR	Fwrite failed.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Wednesday, October 22, 1997
 *
 * Modifications:
 *		June 2, 1998	Albert Cheng
 *		Added xfer_mode argument
 *
 *      Ported to VFL/H5FD layer - QAK, 10/18/99
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
		size_t size, const void *buf)
{
    H5FD_silo_t		*file = (H5FD_silo_t*)_file;
    static const char *func="H5FD_silo_write";  /* Function Name for error reporting */
    herr_t ret_value = 0;
    silo_vfd_block_t *bl;
    silo_vfd_relevant_blocks_t rb;
    hsize_t id, nbytes;
    int blidx, bufoff;

    /* Shut compiler up */
    dxpl_id=dxpl_id;
    type=type;

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow conditions */
    if (HADDR_UNDEF==addr)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)
    if (REGION_OVERFLOW(addr, size))
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)
    if (addr+size>file->eoa)
        H5E_PUSH_HELPER (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1, -1)

    if (size == 0)
        return 0;

    rb = relevant_blocks(file->block_size, addr, size);
    blidx = -1; 
    bl = file->block_list;
    bufoff = 0;
    for (id = rb.id0; id <= rb.id1; id++)
    {
        /* look for the block in the list */
        if (blidx < 0 || blidx >= file->num_blocks-1)
            blidx = find_block_by_id(file, id, EXACT); 
        else if (bl[blidx+1].id != id)
            blidx = find_block_by_id(file, id, EXACT); 
        else
            blidx++;

        if (blidx < 0)
        {
            if (file->num_blocks == file->max_blocks)
            {
                int tmpblidx = find_block_to_preempt(file);
                free_block_by_index(file, tmpblidx);
            }
            blidx = alloc_block_by_id(file, id);
        }

        /* put the data in the block */
	if (id == rb.id0 && id == rb.id1)
	{
	    put_data_to_block_by_index(file, type, buf, size, blidx, rb.off0);
	    bufoff += size;
	}
        else if (id == rb.id0)
	{
	    nbytes = file->block_size - rb.off0;
	    put_data_to_block_by_index(file, type, (const char*)buf+bufoff, nbytes, blidx, rb.off0);
	    bufoff += nbytes;
	}
	else if (id == rb.id1)
	{
	    nbytes = rb.off1+1;
	    put_data_to_block_by_index(file, type, (const char*)buf+bufoff, nbytes, blidx, 0);
	    bufoff += nbytes;
	}
	else
	{
	    put_data_to_block_by_index(file, type, (const char*)buf+bufoff, file->block_size, blidx, 0);
	    bufoff += file->block_size;
	}
    }

    if (file->log_stats)
    {
        int n;
        hsize_t tmpsize = size;
        for (n = 0; tmpsize; n++, tmpsize=(tmpsize>>1));
        if (type == H5FD_MEM_DRAW)
        {
            file->stats.total_vfd_raw_write_count++;
            file->stats.total_vfd_raw_write_bytes += size;
            file->stats.vfd_raw_write_count_hist[n]++;
            file->stats.vfd_raw_write_bytes_hist[n] += size;
        }
        else
        {
            file->stats.total_vfd_md_write_count++;
            file->stats.total_vfd_md_write_bytes += size;
            file->stats.vfd_md_write_count_hist[n]++;
            file->stats.vfd_md_write_bytes_hist[n] += size;
        }
        if (rb.id1 > rb.id0+1)
            file->stats.num_multiblock_writes++;
    }

    return(0);
}

/*-------------------------------------------------------------------------
 * Function:	H5F_silo_truncate
 *
 * Purpose:	Makes sure that the true file size is the same (or larger)
 *		than the end-of-address.
 *
 * Errors:
 *		IO	  SEEKERROR     fseek failed.
 *		IO	  WRITEERROR    fflush or fwrite failed.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		Thursday, January 31, 2008
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_silo_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing)
{
    H5FD_silo_t	*file = (H5FD_silo_t*)_file;
    static const char *func = "H5FD_silo_truncate";  /* Function Name for error reporting */
    herr_t ret_value = 0;

    /* Just skip the truncate */
    return 0;

    /* Shut compiler up */
    dxpl_id = dxpl_id;
    closing = closing;

    HDassert(file);

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Extend the file to make sure it's large enough */
    if(file->write_access && !H5F_addr_eq(file->eoa, file->eof)) {
#ifdef _WIN32
        HFILE filehandle;   /* Windows file handle */
        LARGE_INTEGER li;   /* 64-bit integer for SetFilePointer() call */

        /* Map the posix file handle to a Windows file handle */
        filehandle = _get_osfhandle(file->fd);

        /* Translate 64-bit integers into form Windows wants */
        /* [This algorithm is from the Windows documentation for SetFilePointer()] */
        li.QuadPart = (LONGLONG)file->eoa;
        (void)SetFilePointer((HANDLE)filehandle, li.LowPart, &li.HighPart, FILE_BEGIN);
        if(SetEndOfFile((HANDLE)filehandle) == 0)
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "unable to extend file properly", -1, -1)
#else /* _WIN32 */
#ifdef H5_VMS
        /* Reset seek offset to the beginning of the file, so that the file isn't 
         * re-extended later.  This may happen on Open VMS. */
        if(-1 == HDlseek(file->fd, (file_offset_t)0, SEEK_SET))
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "HDlseek failed", -1, errno)
#endif

        if(-1 == HDftruncate(file->fd, (file_offset_t)file->eoa))
            H5E_PUSH_HELPER(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "HDftruncate failed", -1, errno)
#endif /* _WIN32 */

        /* Update the eof value */
        file->file_eof = file->eoa;

        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

    return(0);
} /* end H5FD_silo_truncate() */

#ifdef _H5private_H
/*
 * This is not related to the functionality of the driver code.
 * It is added here to trigger warning if HDF5 private definitions are included
 * by mistake.  The code should use only HDF5 public API and definitions.
 */
#error "Do not use HDF5 private definitions"
#endif

#endif /* #if HDF5_VERSION_GE(1,8,4) */
#endif /* #if defined(HAVE_HDF5_H) && defined(HAVE_LIBHDF5) */
