jpg.c

/*
 *   This file is part of MiniGUI, a mature cross-platform windowing 
 *   and Graphics User Interface (GUI) support system for embedded systems
 *   and smart IoT devices.
 * 
 *   Copyright (C) 2002~2018, Beijing FMSoft Technologies Co., Ltd.
 *   Copyright (C) 1998~2002, WEI Yongming
 * 
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 * 
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 * 
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 *   Or,
 * 
 *   As this program is a library, any link to this program must follow
 *   GNU General Public License version 3 (GPLv3). If you cannot accept
 *   GPLv3, you need to be licensed from FMSoft.
 * 
 *   If you have got a commercial license of this program, please use it
 *   under the terms and conditions of the commercial license.
 * 
 *   For more information about the commercial license, please refer to
 *   <http://www.minigui.com/en/about/licensing-policy/>.
 */
#include <stdio.h>
#include <memory.h>
#include <stdlib.h>
#include <malloc.h>
#include <setjmp.h>
#include "jpeglib.h"
#include "jpg.h"

struct my_error_mgr {
  struct jpeg_error_mgr pub;	/* "public" fields */
  jmp_buf setjmp_buffer;	/* for return to caller */
};

typedef struct my_error_mgr * my_error_ptr;

METHODDEF(void)
my_error_exit (j_common_ptr cinfo)
{
  /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
  my_error_ptr myerr = (my_error_ptr) cinfo->err;

  /* Always display the message. */
  /* We could postpone this until after returning, if we chose. */
  (*cinfo->err->output_message)(cinfo);

  /* Return control to the setjmp point */
  longjmp(myerr->setjmp_buffer, 1);
}

int unpack_jpg(jpg_info_t* jinfo)
{
    struct jpeg_decompress_struct cinfo;
    /* We use our private extension JPEG error handler.
     * Note that this struct must live as long as the main JPEG parameter
     * struct, to avoid dangling-pointer problems.
     */
    struct my_error_mgr jerr;
    /* More stuff */
    JSAMPARRAY buffer;		/* Output row buffer */
    int row_stride;		    /* physical row width in output buffer */
    
    cinfo.err = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;

    jpeg_create_decompress(&cinfo);

    jpeg_memory_src(&cinfo, jinfo->jpg_buffer, jinfo->jpg_buffer_length);

    jpeg_read_header(&cinfo, TRUE);
    jpeg_start_decompress(&cinfo);

    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    /* Make a one-row-high sample array that will go away when done with image */
    buffer = (*cinfo.mem->alloc_sarray)
	    ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

    jinfo->width=cinfo.output_width;
    jinfo->height=cinfo.output_height;
    jinfo->jpg_surface=(unsigned char*)malloc(jinfo->width*jinfo->height*3);

    while (cinfo.output_scanline < cinfo.output_height) {
        unsigned char* temp_src_buffer;
        unsigned char* temp_des_buffer;

        jpeg_read_scanlines(&cinfo, buffer, 1);

        temp_src_buffer=(unsigned char*)(*buffer);
        temp_des_buffer=jinfo->jpg_surface+jinfo->width*(cinfo.output_scanline-1)*3;

        memcpy(temp_des_buffer,temp_src_buffer,row_stride);
    }

    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);
    return 0;
}

int destroy_jpg(jpg_info_t* jinfo)
{
    if (jinfo->jpg_surface!=NULL) {
        free(jinfo->jpg_surface);
    }
    return 0;
}


#ifndef EXIT_FAILURE		/* define exit() codes if not provided */
#define EXIT_FAILURE  1
#endif


/*
 * Create the message string table.
 * We do this from the master message list in jerror.h by re-reading
 * jerror.h with a suitable definition for macro JMESSAGE.
 * The message table is made an external symbol just in case any applications
 * want to refer to it directly.
 */

#define JMESSAGE(code,string)	string ,

const char * const jpeg_std_message_table[] = {
#include "jpg.h"
  NULL
};


/*
 * Error exit handler: must not return to caller.
 *
 * Applications may override this if they want to get control back after
 * an error.  Typically one would longjmp somewhere instead of exiting.
 * The setjmp buffer can be made a private field within an expanded error
 * handler object.  Note that the info needed to generate an error message
 * is stored in the error object, so you can generate the message now or
 * later, at your convenience.
 * You should make sure that the JPEG object is cleaned up (with jpeg_abort
 * or jpeg_destroy) at some point.
 */

METHODDEF(void)
error_exit (j_common_ptr cinfo)
{
  /* Always display the message */
  (*cinfo->err->output_message) (cinfo);

  /* Let the memory manager delete any temp files before we die */
  jpeg_destroy(cinfo);

}


/*
 * Actual output of an error or trace message.
 * Applications may override this method to send JPEG messages somewhere
 * other than stderr.
 */

METHODDEF(void)
output_message (j_common_ptr cinfo)
{
  char buffer[JMSG_LENGTH_MAX];

  /* Create the message */
  (*cinfo->err->format_message) (cinfo, buffer);

  /* Send it to stderr, adding a newline */
  fprintf(stderr, "%s\n", buffer);
}


/*
 * Decide whether to emit a trace or warning message.
 * msg_level is one of:
 *   -1: recoverable corrupt-data warning, may want to abort.
 *    0: important advisory messages (always display to user).
 *    1: first level of tracing detail.
 *    2,3,...: successively more detailed tracing messages.
 * An application might override this method if it wanted to abort on warnings
 * or change the policy about which messages to display.
 */

METHODDEF(void)
emit_message (j_common_ptr cinfo, int msg_level)
{
  struct jpeg_error_mgr * err = cinfo->err;

  if (msg_level < 0) {
    /* It's a warning message.  Since corrupt files may generate many warnings,
     * the policy implemented here is to show only the first warning,
     * unless trace_level >= 3.
     */
    if (err->num_warnings == 0 || err->trace_level >= 3)
      (*err->output_message) (cinfo);
    /* Always count warnings in num_warnings. */
    err->num_warnings++;
  } else {
    /* It's a trace message.  Show it if trace_level >= msg_level. */
    if (err->trace_level >= msg_level)
      (*err->output_message) (cinfo);
  }
}


/*
 * Format a message string for the most recent JPEG error or message.
 * The message is stored into buffer, which should be at least JMSG_LENGTH_MAX
 * characters.  Note that no '\n' character is added to the string.
 * Few applications should need to override this method.
 */

METHODDEF(void)
format_message (j_common_ptr cinfo, char * buffer)
{
  struct jpeg_error_mgr * err = cinfo->err;
  int msg_code = err->msg_code;
  const char * msgtext = NULL;
  const char * msgptr;
  char ch;
  boolean isstring;

  /* Look up message string in proper table */
  if (msg_code > 0 && msg_code <= err->last_jpeg_message) {
    msgtext = err->jpeg_message_table[msg_code];
  } else if (err->addon_message_table != NULL &&
	     msg_code >= err->first_addon_message &&
	     msg_code <= err->last_addon_message) {
    msgtext = err->addon_message_table[msg_code - err->first_addon_message];
  }

  /* Defend against bogus message number */
  if (msgtext == NULL) {
    err->msg_parm.i[0] = msg_code;
    msgtext = err->jpeg_message_table[0];
  }

  /* Check for string parameter, as indicated by %s in the message text */
  isstring = FALSE;
  msgptr = msgtext;
  while ((ch = *msgptr++) != '\0') {
    if (ch == '%') {
      if (*msgptr == 's') isstring = TRUE;
      break;
    }
  }

  /* Format the message into the passed buffer */
  if (isstring)
    sprintf(buffer, msgtext, err->msg_parm.s);
  else
    sprintf(buffer, msgtext,
	    err->msg_parm.i[0], err->msg_parm.i[1],
	    err->msg_parm.i[2], err->msg_parm.i[3],
	    err->msg_parm.i[4], err->msg_parm.i[5],
	    err->msg_parm.i[6], err->msg_parm.i[7]);
}


/*
 * Reset error state variables at start of a new image.
 * This is called during compression startup to reset trace/error
 * processing to default state, without losing any application-specific
 * method pointers.  An application might possibly want to override
 * this method if it has additional error processing state.
 */

METHODDEF(void)
reset_error_mgr (j_common_ptr cinfo)
{
  cinfo->err->num_warnings = 0;
  /* trace_level is not reset since it is an application-supplied parameter */
  cinfo->err->msg_code = 0;	/* may be useful as a flag for "no error" */
}


/*
 * Fill in the standard error-handling methods in a jpeg_error_mgr object.
 * Typical call is:
 *	struct jpeg_compress_struct cinfo;
 *	struct jpeg_error_mgr err;
 *
 *	cinfo.err = jpeg_std_error(&err);
 * after which the application may override some of the methods.
 */

GLOBAL(struct jpeg_error_mgr *)
jpeg_std_error (struct jpeg_error_mgr * err)
{
  err->error_exit = error_exit;
  err->emit_message = emit_message;
  err->output_message = output_message;
  err->format_message = format_message;
  err->reset_error_mgr = reset_error_mgr;

  err->trace_level = 0;		/* default = no tracing */
  err->num_warnings = 0;	/* no warnings emitted yet */
  err->msg_code = 0;		/* may be useful as a flag for "no error" */

  /* Initialize message table pointers */
  err->jpeg_message_table = jpeg_std_message_table;
  err->last_jpeg_message = (int) JMSG_LASTMSGCODE - 1;

  err->addon_message_table = NULL;
  err->first_addon_message = 0;	/* for safety */
  err->last_addon_message = 0;

  return err;
}

#define JPEG_INTERNALS
#include "jpegint.h"
#define AM_MEMORY_MANAGER	/* we define jvirt_Xarray_control structs */

#ifndef NO_GETENV
#ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare getenv() */
extern char * getenv JPP((const char * name));
#endif
#endif


/*
 * Some important notes:
 *   The allocation routines provided here must never return NULL.
 *   They should exit to error_exit if unsuccessful.
 *
 *   It's not a good idea to try to merge the sarray and barray routines,
 *   even though they are textually almost the same, because samples are
 *   usually stored as bytes while coefficients are shorts or ints.  Thus,
 *   in machines where byte pointers have a different representation from
 *   word pointers, the resulting machine code could not be the same.
 */


/*
 * Many machines require storage alignment: longs must start on 4-byte
 * boundaries, doubles on 8-byte boundaries, etc.  On such machines, malloc()
 * always returns pointers that are multiples of the worst-case alignment
 * requirement, and we had better do so too.
 * There isn't any really portable way to determine the worst-case alignment
 * requirement.  This module assumes that the alignment requirement is
 * multiples of sizeof(ALIGN_TYPE).
 * By default, we define ALIGN_TYPE as double.  This is necessary on some
 * workstations (where doubles really do need 8-byte alignment) and will work
 * fine on nearly everything.  If your machine has lesser alignment needs,
 * you can save a few bytes by making ALIGN_TYPE smaller.
 * The only place I know of where this will NOT work is certain Macintosh
 * 680x0 compilers that define double as a 10-byte IEEE extended float.
 * Doing 10-byte alignment is counterproductive because longwords won't be
 * aligned well.  Put "#define ALIGN_TYPE long" in jconfig.h if you have
 * such a compiler.
 */

#ifndef ALIGN_TYPE		/* so can override from jconfig.h */
#define ALIGN_TYPE  double
#endif


/*
 * We allocate objects from "pools", where each pool is gotten with a single
 * request to jpeg_get_small() or jpeg_get_large().  There is no per-object
 * overhead within a pool, except for alignment padding.  Each pool has a
 * header with a link to the next pool of the same class.
 * Small and large pool headers are identical except that the latter's
 * link pointer must be FAR on 80x86 machines.
 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
 * field.  This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
 * of the alignment requirement of ALIGN_TYPE.
 */

typedef union small_pool_struct * small_pool_ptr;

typedef union small_pool_struct {
  struct {
    small_pool_ptr next;	/* next in list of pools */
    size_t bytes_used;		/* how many bytes already used within pool */
    size_t bytes_left;		/* bytes still available in this pool */
  } hdr;
  ALIGN_TYPE dummy;		/* included in union to ensure alignment */
} small_pool_hdr;

typedef union large_pool_struct * large_pool_ptr;

typedef union large_pool_struct {
  struct {
    large_pool_ptr next;	/* next in list of pools */
    size_t bytes_used;		/* how many bytes already used within pool */
    size_t bytes_left;		/* bytes still available in this pool */
  } hdr;
  ALIGN_TYPE dummy;		/* included in union to ensure alignment */
} large_pool_hdr;


/*
 * Here is the full definition of a memory manager object.
 */

typedef struct {
  struct jpeg_memory_mgr pub;	/* public fields */

  /* Each pool identifier (lifetime class) names a linked list of pools. */
  small_pool_ptr small_list[JPOOL_NUMPOOLS];
  large_pool_ptr large_list[JPOOL_NUMPOOLS];

  /* Since we only have one lifetime class of virtual arrays, only one
   * linked list is necessary (for each datatype).  Note that the virtual
   * array control blocks being linked together are actually stored somewhere
   * in the small-pool list.
   */
  jvirt_sarray_ptr virt_sarray_list;
  jvirt_barray_ptr virt_barray_list;

  /* This counts total space obtained from jpeg_get_small/large */
  long total_space_allocated;

  /* alloc_sarray and alloc_barray set this value for use by virtual
   * array routines.
   */
  JDIMENSION last_rowsperchunk;	/* from most recent alloc_sarray/barray */
} my_memory_mgr;

typedef my_memory_mgr * my_mem_ptr;


/*
 * The control blocks for virtual arrays.
 * Note that these blocks are allocated in the "small" pool area.
 * System-dependent info for the associated backing store (if any) is hidden
 * inside the backing_store_info struct.
 */

struct jvirt_sarray_control {
  JSAMPARRAY mem_buffer;	/* => the in-memory buffer */
  JDIMENSION rows_in_array;	/* total virtual array height */
  JDIMENSION samplesperrow;	/* width of array (and of memory buffer) */
  JDIMENSION maxaccess;		/* max rows accessed by access_virt_sarray */
  JDIMENSION rows_in_mem;	/* height of memory buffer */
  JDIMENSION rowsperchunk;	/* allocation chunk size in mem_buffer */
  JDIMENSION cur_start_row;	/* first logical row # in the buffer */
  JDIMENSION first_undef_row;	/* row # of first uninitialized row */
  boolean pre_zero;		/* pre-zero mode requested? */
  boolean dirty;		/* do current buffer contents need written? */
  boolean b_s_open;		/* is backing-store data valid? */
  jvirt_sarray_ptr next;	/* link to next virtual sarray control block */
  backing_store_info b_s_info;	/* System-dependent control info */
};

struct jvirt_barray_control {
  JBLOCKARRAY mem_buffer;	/* => the in-memory buffer */
  JDIMENSION rows_in_array;	/* total virtual array height */
  JDIMENSION blocksperrow;	/* width of array (and of memory buffer) */
  JDIMENSION maxaccess;		/* max rows accessed by access_virt_barray */
  JDIMENSION rows_in_mem;	/* height of memory buffer */
  JDIMENSION rowsperchunk;	/* allocation chunk size in mem_buffer */
  JDIMENSION cur_start_row;	/* first logical row # in the buffer */
  JDIMENSION first_undef_row;	/* row # of first uninitialized row */
  boolean pre_zero;		/* pre-zero mode requested? */
  boolean dirty;		/* do current buffer contents need written? */
  boolean b_s_open;		/* is backing-store data valid? */
  jvirt_barray_ptr next;	/* link to next virtual barray control block */
  backing_store_info b_s_info;	/* System-dependent control info */
};


#ifdef MEM_STATS		/* optional extra stuff for statistics */

LOCAL(void)
print_mem_stats (j_common_ptr cinfo, int pool_id)
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  small_pool_ptr shdr_ptr;
  large_pool_ptr lhdr_ptr;

  /* Since this is only a debugging stub, we can cheat a little by using
   * fprintf directly rather than going through the trace message code.
   * This is helpful because message parm array can't handle longs.
   */
  fprintf(stderr, "Freeing pool %d, total space = %ld\n",
	  pool_id, mem->total_space_allocated);

  for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
       lhdr_ptr = lhdr_ptr->hdr.next) {
    fprintf(stderr, "  Large chunk used %ld\n",
	    (long) lhdr_ptr->hdr.bytes_used);
  }

  for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
       shdr_ptr = shdr_ptr->hdr.next) {
    fprintf(stderr, "  Small chunk used %ld free %ld\n",
	    (long) shdr_ptr->hdr.bytes_used,
	    (long) shdr_ptr->hdr.bytes_left);
  }
}

#endif /* MEM_STATS */


LOCAL(void)
out_of_memory (j_common_ptr cinfo, int which)
/* Report an out-of-memory error and stop execution */
/* If we compiled MEM_STATS support, report alloc requests before dying */
{
#ifdef MEM_STATS
  cinfo->err->trace_level = 2;	/* force self_destruct to report stats */
#endif
  ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
}


/*
 * Allocation of "small" objects.
 *
 * For these, we use pooled storage.  When a new pool must be created,
 * we try to get enough space for the current request plus a "slop" factor,
 * where the slop will be the amount of leftover space in the new pool.
 * The speed vs. space tradeoff is largely determined by the slop values.
 * A different slop value is provided for each pool class (lifetime),
 * and we also distinguish the first pool of a class from later ones.
 * NOTE: the values given work fairly well on both 16- and 32-bit-int
 * machines, but may be too small if longs are 64 bits or more.
 */

static const size_t first_pool_slop[JPOOL_NUMPOOLS] = 
{
	1600,			/* first PERMANENT pool */
	16000			/* first IMAGE pool */
};

static const size_t extra_pool_slop[JPOOL_NUMPOOLS] = 
{
	0,			/* additional PERMANENT pools */
	5000			/* additional IMAGE pools */
};

#define MIN_SLOP  50		/* greater than 0 to avoid futile looping */


METHODDEF(void *)
alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
/* Allocate a "small" object */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  small_pool_ptr hdr_ptr, prev_hdr_ptr;
  char * data_ptr;
  size_t odd_bytes, min_request, slop;

  /* Check for unsatisfiable request (do now to ensure no overflow below) */
  if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
    out_of_memory(cinfo, 1);	/* request exceeds malloc's ability */

  /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
  odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
  if (odd_bytes > 0)
    sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;

  /* See if space is available in any existing pool */
  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
  prev_hdr_ptr = NULL;
  hdr_ptr = mem->small_list[pool_id];
  while (hdr_ptr != NULL) {
    if (hdr_ptr->hdr.bytes_left >= sizeofobject)
      break;			/* found pool with enough space */
    prev_hdr_ptr = hdr_ptr;
    hdr_ptr = hdr_ptr->hdr.next;
  }

  /* Time to make a new pool? */
  if (hdr_ptr == NULL) {
    /* min_request is what we need now, slop is what will be leftover */
    min_request = sizeofobject + SIZEOF(small_pool_hdr);
    if (prev_hdr_ptr == NULL)	/* first pool in class? */
      slop = first_pool_slop[pool_id];
    else
      slop = extra_pool_slop[pool_id];
    /* Don't ask for more than MAX_ALLOC_CHUNK */
    if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
      slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
    /* Try to get space, if fail reduce slop and try again */
    for (;;) {
      hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
      if (hdr_ptr != NULL)
	break;
      slop /= 2;
      if (slop < MIN_SLOP)	/* give up when it gets real small */
	out_of_memory(cinfo, 2); /* jpeg_get_small failed */
    }
    mem->total_space_allocated += min_request + slop;
    /* Success, initialize the new pool header and add to end of list */
    hdr_ptr->hdr.next = NULL;
    hdr_ptr->hdr.bytes_used = 0;
    hdr_ptr->hdr.bytes_left = sizeofobject + slop;
    if (prev_hdr_ptr == NULL)	/* first pool in class? */
      mem->small_list[pool_id] = hdr_ptr;
    else
      prev_hdr_ptr->hdr.next = hdr_ptr;
  }

  /* OK, allocate the object from the current pool */
  data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
  data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
  hdr_ptr->hdr.bytes_used += sizeofobject;
  hdr_ptr->hdr.bytes_left -= sizeofobject;

  return (void *) data_ptr;
}


/*
 * Allocation of "large" objects.
 *
 * The external semantics of these are the same as "small" objects,
 * except that FAR pointers are used on 80x86.  However the pool
 * management heuristics are quite different.  We assume that each
 * request is large enough that it may as well be passed directly to
 * jpeg_get_large; the pool management just links everything together
 * so that we can free it all on demand.
 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
 * structures.  The routines that create these structures (see below)
 * deliberately bunch rows together to ensure a large request size.
 */

METHODDEF(void *)
alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
/* Allocate a "large" object */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  large_pool_ptr hdr_ptr;
  size_t odd_bytes;

  /* Check for unsatisfiable request (do now to ensure no overflow below) */
  if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
    out_of_memory(cinfo, 3);	/* request exceeds malloc's ability */

  /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
  odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
  if (odd_bytes > 0)
    sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;

  /* Always make a new pool */
  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */

  hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
					    SIZEOF(large_pool_hdr));
  if (hdr_ptr == NULL)
    out_of_memory(cinfo, 4);	/* jpeg_get_large failed */
  mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);

  /* Success, initialize the new pool header and add to list */
  hdr_ptr->hdr.next = mem->large_list[pool_id];
  /* We maintain space counts in each pool header for statistical purposes,
   * even though they are not needed for allocation.
   */
  hdr_ptr->hdr.bytes_used = sizeofobject;
  hdr_ptr->hdr.bytes_left = 0;
  mem->large_list[pool_id] = hdr_ptr;

  return (void *) (hdr_ptr + 1); /* point to first data byte in pool */
}


/*
 * Creation of 2-D sample arrays.
 * The pointers are in near heap, the samples themselves in FAR heap.
 *
 * To minimize allocation overhead and to allow I/O of large contiguous
 * blocks, we allocate the sample rows in groups of as many rows as possible
 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
 * NB: the virtual array control routines, later in this file, know about
 * this chunking of rows.  The rowsperchunk value is left in the mem manager
 * object so that it can be saved away if this sarray is the workspace for
 * a virtual array.
 */

METHODDEF(JSAMPARRAY)
alloc_sarray (j_common_ptr cinfo, int pool_id,
	      JDIMENSION samplesperrow, JDIMENSION numrows)
/* Allocate a 2-D sample array */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  JSAMPARRAY result;
  JSAMPROW workspace;
  JDIMENSION rowsperchunk, currow, i;
  long ltemp;

  /* Calculate max # of rows allowed in one allocation chunk */
  ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
	  ((long) samplesperrow * SIZEOF(JSAMPLE));
  if (ltemp <= 0)
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
  if (ltemp < (long) numrows)
    rowsperchunk = (JDIMENSION) ltemp;
  else
    rowsperchunk = numrows;
  mem->last_rowsperchunk = rowsperchunk;

  /* Get space for row pointers (small object) */
  result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
				    (size_t) (numrows * SIZEOF(JSAMPROW)));

  /* Get the rows themselves (large objects) */
  currow = 0;
  while (currow < numrows) {
    rowsperchunk = MIN(rowsperchunk, numrows - currow);
    workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
	(size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
		  * SIZEOF(JSAMPLE)));
    for (i = rowsperchunk; i > 0; i--) {
      result[currow++] = workspace;
      workspace += samplesperrow;
    }
  }

  return result;
}


/*
 * Creation of 2-D coefficient-block arrays.
 * This is essentially the same as the code for sample arrays, above.
 */

METHODDEF(JBLOCKARRAY)
alloc_barray (j_common_ptr cinfo, int pool_id,
	      JDIMENSION blocksperrow, JDIMENSION numrows)
/* Allocate a 2-D coefficient-block array */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  JBLOCKARRAY result;
  JBLOCKROW workspace;
  JDIMENSION rowsperchunk, currow, i;
  long ltemp;

  /* Calculate max # of rows allowed in one allocation chunk */
  ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
	  ((long) blocksperrow * SIZEOF(JBLOCK));
  if (ltemp <= 0)
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
  if (ltemp < (long) numrows)
    rowsperchunk = (JDIMENSION) ltemp;
  else
    rowsperchunk = numrows;
  mem->last_rowsperchunk = rowsperchunk;

  /* Get space for row pointers (small object) */
  result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
				     (size_t) (numrows * SIZEOF(JBLOCKROW)));

  /* Get the rows themselves (large objects) */
  currow = 0;
  while (currow < numrows) {
    rowsperchunk = MIN(rowsperchunk, numrows - currow);
    workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
	(size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
		  * SIZEOF(JBLOCK)));
    for (i = rowsperchunk; i > 0; i--) {
      result[currow++] = workspace;
      workspace += blocksperrow;
    }
  }

  return result;
}


/*
 * About virtual array management:
 *
 * The above "normal" array routines are only used to allocate strip buffers
 * (as wide as the image, but just a few rows high).  Full-image-sized buffers
 * are handled as "virtual" arrays.  The array is still accessed a strip at a
 * time, but the memory manager must save the whole array for repeated
 * accesses.  The intended implementation is that there is a strip buffer in
 * memory (as high as is possible given the desired memory limit), plus a
 * backing file that holds the rest of the array.
 *
 * The request_virt_array routines are told the total size of the image and
 * the maximum number of rows that will be accessed at once.  The in-memory
 * buffer must be at least as large as the maxaccess value.
 *
 * The request routines create control blocks but not the in-memory buffers.
 * That is postponed until realize_virt_arrays is called.  At that time the
 * total amount of space needed is known (approximately, anyway), so free
 * memory can be divided up fairly.
 *
 * The access_virt_array routines are responsible for making a specific strip
 * area accessible (after reading or writing the backing file, if necessary).
 * Note that the access routines are told whether the caller intends to modify
 * the accessed strip; during a read-only pass this saves having to rewrite
 * data to disk.  The access routines are also responsible for pre-zeroing
 * any newly accessed rows, if pre-zeroing was requested.
 *
 * In current usage, the access requests are usually for nonoverlapping
 * strips; that is, successive access start_row numbers differ by exactly
 * num_rows = maxaccess.  This means we can get good performance with simple
 * buffer dump/reload logic, by making the in-memory buffer be a multiple
 * of the access height; then there will never be accesses across bufferload
 * boundaries.  The code will still work with overlapping access requests,
 * but it doesn't handle bufferload overlaps very efficiently.
 */


METHODDEF(jvirt_sarray_ptr)
request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
		     JDIMENSION samplesperrow, JDIMENSION numrows,
		     JDIMENSION maxaccess)
/* Request a virtual 2-D sample array */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  jvirt_sarray_ptr result;

  /* Only IMAGE-lifetime virtual arrays are currently supported */
  if (pool_id != JPOOL_IMAGE)
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */

  /* get control block */
  result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
					  SIZEOF(struct jvirt_sarray_control));

  result->mem_buffer = NULL;	/* marks array not yet realized */
  result->rows_in_array = numrows;
  result->samplesperrow = samplesperrow;
  result->maxaccess = maxaccess;
  result->pre_zero = pre_zero;
  result->b_s_open = FALSE;	/* no associated backing-store object */
  result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
  mem->virt_sarray_list = result;

  return result;
}


METHODDEF(jvirt_barray_ptr)
request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
		     JDIMENSION blocksperrow, JDIMENSION numrows,
		     JDIMENSION maxaccess)
/* Request a virtual 2-D coefficient-block array */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  jvirt_barray_ptr result;

  /* Only IMAGE-lifetime virtual arrays are currently supported */
  if (pool_id != JPOOL_IMAGE)
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */

  /* get control block */
  result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
					  SIZEOF(struct jvirt_barray_control));

  result->mem_buffer = NULL;	/* marks array not yet realized */
  result->rows_in_array = numrows;
  result->blocksperrow = blocksperrow;
  result->maxaccess = maxaccess;
  result->pre_zero = pre_zero;
  result->b_s_open = FALSE;	/* no associated backing-store object */
  result->next = mem->virt_barray_list; /* add to list of virtual arrays */
  mem->virt_barray_list = result;

  return result;
}


METHODDEF(void)
realize_virt_arrays (j_common_ptr cinfo)
/* Allocate the in-memory buffers for any unrealized virtual arrays */
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  long space_per_minheight, maximum_space, avail_mem;
  long minheights, max_minheights;
  jvirt_sarray_ptr sptr;
  jvirt_barray_ptr bptr;

  /* Compute the minimum space needed (maxaccess rows in each buffer)
   * and the maximum space needed (full image height in each buffer).
   * These may be of use to the system-dependent jpeg_mem_available routine.
   */
  space_per_minheight = 0;
  maximum_space = 0;
  for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
    if (sptr->mem_buffer == NULL) { /* if not realized yet */
      space_per_minheight += (long) sptr->maxaccess *
			     (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
      maximum_space += (long) sptr->rows_in_array *
		       (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
    }
  }
  for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
    if (bptr->mem_buffer == NULL) { /* if not realized yet */
      space_per_minheight += (long) bptr->maxaccess *
			     (long) bptr->blocksperrow * SIZEOF(JBLOCK);
      maximum_space += (long) bptr->rows_in_array *
		       (long) bptr->blocksperrow * SIZEOF(JBLOCK);
    }
  }

  if (space_per_minheight <= 0)
    return;			/* no unrealized arrays, no work */

  /* Determine amount of memory to actually use; this is system-dependent. */
  avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
				 mem->total_space_allocated);

  /* If the maximum space needed is available, make all the buffers full
   * height; otherwise parcel it out with the same number of minheights
   * in each buffer.
   */
  if (avail_mem >= maximum_space)
    max_minheights = 1000000000L;
  else {
    max_minheights = avail_mem / space_per_minheight;
    /* If there doesn't seem to be enough space, try to get the minimum
     * anyway.  This allows a "stub" implementation of jpeg_mem_available().
     */
    if (max_minheights <= 0)
      max_minheights = 1;
  }

  /* Allocate the in-memory buffers and initialize backing store as needed. */

  for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
    if (sptr->mem_buffer == NULL) { /* if not realized yet */
      minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
      if (minheights <= max_minheights) {
	/* This buffer fits in memory */
	sptr->rows_in_mem = sptr->rows_in_array;
      } else {
	/* It doesn't fit in memory, create backing store. */
	sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
	jpeg_open_backing_store(cinfo, & sptr->b_s_info,
				(long) sptr->rows_in_array *
				(long) sptr->samplesperrow *
				(long) SIZEOF(JSAMPLE));
	sptr->b_s_open = TRUE;
      }
      sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
				      sptr->samplesperrow, sptr->rows_in_mem);
      sptr->rowsperchunk = mem->last_rowsperchunk;
      sptr->cur_start_row = 0;
      sptr->first_undef_row = 0;
      sptr->dirty = FALSE;
    }
  }

  for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
    if (bptr->mem_buffer == NULL) { /* if not realized yet */
      minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
      if (minheights <= max_minheights) {
	/* This buffer fits in memory */
	bptr->rows_in_mem = bptr->rows_in_array;
      } else {
	/* It doesn't fit in memory, create backing store. */
	bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
	jpeg_open_backing_store(cinfo, & bptr->b_s_info,
				(long) bptr->rows_in_array *
				(long) bptr->blocksperrow *
				(long) SIZEOF(JBLOCK));
	bptr->b_s_open = TRUE;
      }
      bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
				      bptr->blocksperrow, bptr->rows_in_mem);
      bptr->rowsperchunk = mem->last_rowsperchunk;
      bptr->cur_start_row = 0;
      bptr->first_undef_row = 0;
      bptr->dirty = FALSE;
    }
  }
}


LOCAL(void)
do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
/* Do backing store read or write of a virtual sample array */
{
  long bytesperrow, file_offset, byte_count, rows, thisrow, i;

  bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
  file_offset = ptr->cur_start_row * bytesperrow;
  /* Loop to read or write each allocation chunk in mem_buffer */
  for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
    /* One chunk, but check for short chunk at end of buffer */
    rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
    /* Transfer no more than is currently defined */
    thisrow = (long) ptr->cur_start_row + i;
    rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
    /* Transfer no more than fits in file */
    rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
    if (rows <= 0)		/* this chunk might be past end of file! */
      break;
    byte_count = rows * bytesperrow;
    if (writing)
      (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
					    (void *) ptr->mem_buffer[i],
					    file_offset, byte_count);
    else
      (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
					   (void *) ptr->mem_buffer[i],
					   file_offset, byte_count);
    file_offset += byte_count;
  }
}


LOCAL(void)
do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
/* Do backing store read or write of a virtual coefficient-block array */
{
  long bytesperrow, file_offset, byte_count, rows, thisrow, i;

  bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
  file_offset = ptr->cur_start_row * bytesperrow;
  /* Loop to read or write each allocation chunk in mem_buffer */
  for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
    /* One chunk, but check for short chunk at end of buffer */
    rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
    /* Transfer no more than is currently defined */
    thisrow = (long) ptr->cur_start_row + i;
    rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
    /* Transfer no more than fits in file */
    rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
    if (rows <= 0)		/* this chunk might be past end of file! */
      break;
    byte_count = rows * bytesperrow;
    if (writing)
      (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
					    (void *) ptr->mem_buffer[i],
					    file_offset, byte_count);
    else
      (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
					   (void *) ptr->mem_buffer[i],
					   file_offset, byte_count);
    file_offset += byte_count;
  }
}


METHODDEF(JSAMPARRAY)
access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
		    JDIMENSION start_row, JDIMENSION num_rows,
		    boolean writable)
/* Access the part of a virtual sample array starting at start_row */
/* and extending for num_rows rows.  writable is true if  */
/* caller intends to modify the accessed area. */
{
  JDIMENSION end_row = start_row + num_rows;
  JDIMENSION undef_row;

  /* debugging check */
  if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
      ptr->mem_buffer == NULL)
    ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);

  /* Make the desired part of the virtual array accessible */
  if (start_row < ptr->cur_start_row ||
      end_row > ptr->cur_start_row+ptr->rows_in_mem) {
    if (! ptr->b_s_open)
      ERREXIT(cinfo, JERR_VIRTUAL_BUG);
    /* Flush old buffer contents if necessary */
    if (ptr->dirty) {
      do_sarray_io(cinfo, ptr, TRUE);
      ptr->dirty = FALSE;
    }
    /* Decide what part of virtual array to access.
     * Algorithm: if target address > current window, assume forward scan,
     * load starting at target address.  If target address < current window,
     * assume backward scan, load so that target area is top of window.
     * Note that when switching from forward write to forward read, will have
     * start_row = 0, so the limiting case applies and we load from 0 anyway.
     */
    if (start_row > ptr->cur_start_row) {
      ptr->cur_start_row = start_row;
    } else {
      /* use long arithmetic here to avoid overflow & unsigned problems */
      long ltemp;

      ltemp = (long) end_row - (long) ptr->rows_in_mem;
      if (ltemp < 0)
	ltemp = 0;		/* don't fall off front end of file */
      ptr->cur_start_row = (JDIMENSION) ltemp;
    }
    /* Read in the selected part of the array.
     * During the initial write pass, we will do no actual read
     * because the selected part is all undefined.
     */
    do_sarray_io(cinfo, ptr, FALSE);
  }
  /* Ensure the accessed part of the array is defined; prezero if needed.
   * To improve locality of access, we only prezero the part of the array
   * that the caller is about to access, not the entire in-memory array.
   */
  if (ptr->first_undef_row < end_row) {
    if (ptr->first_undef_row < start_row) {
      if (writable)		/* writer skipped over a section of array */
	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
      undef_row = start_row;	/* but reader is allowed to read ahead */
    } else {
      undef_row = ptr->first_undef_row;
    }
    if (writable)
      ptr->first_undef_row = end_row;
    if (ptr->pre_zero) {
      size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
      undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
      end_row -= ptr->cur_start_row;
      while (undef_row < end_row) {
	jzero_far((void *) ptr->mem_buffer[undef_row], bytesperrow);
	undef_row++;
      }
    } else {
      if (! writable)		/* reader looking at undefined data */
	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
    }
  }
  /* Flag the buffer dirty if caller will write in it */
  if (writable)
    ptr->dirty = TRUE;
  /* Return address of proper part of the buffer */
  return ptr->mem_buffer + (start_row - ptr->cur_start_row);
}


METHODDEF(JBLOCKARRAY)
access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
		    JDIMENSION start_row, JDIMENSION num_rows,
		    boolean writable)
/* Access the part of a virtual block array starting at start_row */
/* and extending for num_rows rows.  writable is true if  */
/* caller intends to modify the accessed area. */
{
  JDIMENSION end_row = start_row + num_rows;
  JDIMENSION undef_row;

  /* debugging check */
  if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
      ptr->mem_buffer == NULL)
    ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);

  /* Make the desired part of the virtual array accessible */
  if (start_row < ptr->cur_start_row ||
      end_row > ptr->cur_start_row+ptr->rows_in_mem) {
    if (! ptr->b_s_open)
      ERREXIT(cinfo, JERR_VIRTUAL_BUG);
    /* Flush old buffer contents if necessary */
    if (ptr->dirty) {
      do_barray_io(cinfo, ptr, TRUE);
      ptr->dirty = FALSE;
    }
    /* Decide what part of virtual array to access.
     * Algorithm: if target address > current window, assume forward scan,
     * load starting at target address.  If target address < current window,
     * assume backward scan, load so that target area is top of window.
     * Note that when switching from forward write to forward read, will have
     * start_row = 0, so the limiting case applies and we load from 0 anyway.
     */
    if (start_row > ptr->cur_start_row) {
      ptr->cur_start_row = start_row;
    } else {
      /* use long arithmetic here to avoid overflow & unsigned problems */
      long ltemp;

      ltemp = (long) end_row - (long) ptr->rows_in_mem;
      if (ltemp < 0)
	ltemp = 0;		/* don't fall off front end of file */
      ptr->cur_start_row = (JDIMENSION) ltemp;
    }
    /* Read in the selected part of the array.
     * During the initial write pass, we will do no actual read
     * because the selected part is all undefined.
     */
    do_barray_io(cinfo, ptr, FALSE);
  }
  /* Ensure the accessed part of the array is defined; prezero if needed.
   * To improve locality of access, we only prezero the part of the array
   * that the caller is about to access, not the entire in-memory array.
   */
  if (ptr->first_undef_row < end_row) {
    if (ptr->first_undef_row < start_row) {
      if (writable)		/* writer skipped over a section of array */
	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
      undef_row = start_row;	/* but reader is allowed to read ahead */
    } else {
      undef_row = ptr->first_undef_row;
    }
    if (writable)
      ptr->first_undef_row = end_row;
    if (ptr->pre_zero) {
      size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
      undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
      end_row -= ptr->cur_start_row;
      while (undef_row < end_row) {
	jzero_far((void *) ptr->mem_buffer[undef_row], bytesperrow);
	undef_row++;
      }
    } else {
      if (! writable)		/* reader looking at undefined data */
	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
    }
  }
  /* Flag the buffer dirty if caller will write in it */
  if (writable)
    ptr->dirty = TRUE;
  /* Return address of proper part of the buffer */
  return ptr->mem_buffer + (start_row - ptr->cur_start_row);
}


/*
 * Release all objects belonging to a specified pool.
 */

METHODDEF(void)
free_pool (j_common_ptr cinfo, int pool_id)
{
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
  small_pool_ptr shdr_ptr;
  large_pool_ptr lhdr_ptr;
  size_t space_freed;

  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */

#ifdef MEM_STATS
  if (cinfo->err->trace_level > 1)
    print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
#endif

  /* If freeing IMAGE pool, close any virtual arrays first */
  if (pool_id == JPOOL_IMAGE) {
    jvirt_sarray_ptr sptr;
    jvirt_barray_ptr bptr;

    for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
      if (sptr->b_s_open) {	/* there may be no backing store */
	sptr->b_s_open = FALSE;	/* prevent recursive close if error */
	(*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
      }
    }
    mem->virt_sarray_list = NULL;
    for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
      if (bptr->b_s_open) {	/* there may be no backing store */
	bptr->b_s_open = FALSE;	/* prevent recursive close if error */
	(*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
      }
    }
    mem->virt_barray_list = NULL;
  }

  /* Release large objects */
  lhdr_ptr = mem->large_list[pool_id];
  mem->large_list[pool_id] = NULL;

  while (lhdr_ptr != NULL) {
    large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
    space_freed = lhdr_ptr->hdr.bytes_used +
		  lhdr_ptr->hdr.bytes_left +
		  SIZEOF(large_pool_hdr);
    jpeg_free_large(cinfo, (void *) lhdr_ptr, space_freed);
    mem->total_space_allocated -= space_freed;
    lhdr_ptr = next_lhdr_ptr;
  }

  /* Release small objects */
  shdr_ptr = mem->small_list[pool_id];
  mem->small_list[pool_id] = NULL;

  while (shdr_ptr != NULL) {
    small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
    space_freed = shdr_ptr->hdr.bytes_used +
		  shdr_ptr->hdr.bytes_left +
		  SIZEOF(small_pool_hdr);
    jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
    mem->total_space_allocated -= space_freed;
    shdr_ptr = next_shdr_ptr;
  }
}


/*
 * Close up shop entirely.
 * Note that this cannot be called unless cinfo->mem is non-NULL.
 */

METHODDEF(void)
self_destruct (j_common_ptr cinfo)
{
  int pool;

  /* Close all backing store, release all memory.
   * Releasing pools in reverse order might help avoid fragmentation
   * with some (brain-damaged) malloc libraries.
   */
  for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
    free_pool(cinfo, pool);
  }

  /* Release the memory manager control block too. */
  jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
  cinfo->mem = NULL;		/* ensures I will be called only once */

  jpeg_mem_term(cinfo);		/* system-dependent cleanup */
}


/*
 * Memory manager initialization.
 * When this is called, only the error manager pointer is valid in cinfo!
 */

GLOBAL(void)
jinit_memory_mgr (j_common_ptr cinfo)
{
  my_mem_ptr mem;
  long max_to_use;
  int pool;
  size_t test_mac;

  cinfo->mem = NULL;		/* for safety if init fails */

  /* Check for configuration errors.
   * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
   * doesn't reflect any real hardware alignment requirement.
   * The test is a little tricky: for X>0, X and X-1 have no one-bits
   * in common if and only if X is a power of 2, ie has only one one-bit.
   * Some compilers may give an "unreachable code" warning here; ignore it.
   */
  if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
    ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
  /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
   * a multiple of SIZEOF(ALIGN_TYPE).
   * Again, an "unreachable code" warning may be ignored here.
   * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
   */
  test_mac = (size_t) MAX_ALLOC_CHUNK;
  if ((long) test_mac != MAX_ALLOC_CHUNK ||
      (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
    ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);

  max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */

  /* Attempt to allocate memory manager's control block */
  mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));

  if (mem == NULL) {
    jpeg_mem_term(cinfo);	/* system-dependent cleanup */
    ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
  }

  /* OK, fill in the method pointers */
  mem->pub.alloc_small = alloc_small;
  mem->pub.alloc_large = alloc_large;
  mem->pub.alloc_sarray = alloc_sarray;
  mem->pub.alloc_barray = alloc_barray;
  mem->pub.request_virt_sarray = request_virt_sarray;
  mem->pub.request_virt_barray = request_virt_barray;
  mem->pub.realize_virt_arrays = realize_virt_arrays;
  mem->pub.access_virt_sarray = access_virt_sarray;
  mem->pub.access_virt_barray = access_virt_barray;
  mem->pub.free_pool = free_pool;
  mem->pub.self_destruct = self_destruct;

  /* Initialize working state */
  mem->pub.max_memory_to_use = max_to_use;

  for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
    mem->small_list[pool] = NULL;
    mem->large_list[pool] = NULL;
  }
  mem->virt_sarray_list = NULL;
  mem->virt_barray_list = NULL;

  mem->total_space_allocated = SIZEOF(my_memory_mgr);

  /* Declare ourselves open for business */
  cinfo->mem = & mem->pub;

  /* Check for an environment variable JPEGMEM; if found, override the
   * default max_memory setting from jpeg_mem_init.  Note that the
   * surrounding application may again override this value.
   * If your system doesn't support getenv(), define NO_GETENV to disable
   * this feature.
   */
#ifndef NO_GETENV
  { char * memenv;

    if ((memenv = getenv("JPEGMEM")) != NULL) {
      char ch = 'x';

      if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
	if (ch == 'm' || ch == 'M')
	  max_to_use *= 1000L;
	mem->pub.max_memory_to_use = max_to_use * 1000L;
      }
    }
  }
#endif

}

#define JPEG_INTERNALS

#ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare malloc(),free() */
extern void * malloc JPP((size_t size));
extern void free JPP((void *ptr));
#endif


/*
 * Memory allocation and freeing are controlled by the regular library
 * routines malloc() and free().
 */

GLOBAL(void *)
jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
{
  return (void *) malloc(sizeofobject);
}

GLOBAL(void)
jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)
{
  free(object);
}


/*
 * "Large" objects are treated the same as "small" ones.
 * NB: although we include keywords in the routine declarations,
 * this file won't actually work in 80x86 small/medium model; at least,
 * you probably won't be able to process useful-size images in only 64KB.
 */

GLOBAL(void *)
jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
{
  return (void *) malloc(sizeofobject);
}

GLOBAL(void)
jpeg_free_large (j_common_ptr cinfo, void * object, size_t sizeofobject)
{
  free(object);
}


/*
 * This routine computes the total memory space available for allocation.
 * Here we always say, "we got all you want bud!"
 */

GLOBAL(long)
jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
		    long max_bytes_needed, long already_allocated)
{
  return max_bytes_needed;
}


/*
 * Backing store (temporary file) management.
 * Since jpeg_mem_available always promised the moon,
 * this should never be called and we can just error out.
 */

GLOBAL(void)
jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
			 long total_bytes_needed)
{
  ERREXIT(cinfo, JERR_NO_BACKING_STORE);
}


/*
 * These routines take care of any system-dependent initialization and
 * cleanup required.  Here, there isn't any.
 */

GLOBAL(long)
jpeg_mem_init (j_common_ptr cinfo)
{
  return 0;			/* just set max_memory_to_use to 0 */
}

GLOBAL(void)
jpeg_mem_term (j_common_ptr cinfo)
{
  /* no work */
}