#include "jinclude.h"
#include "jpeglib.h"
#include "jmemsys.h"

Include dependency graph for jmemmgr.cpp:

Classes
union	small_pool_struct

union	large_pool_struct

struct	my_memory_mgr

struct	jvirt_sarray_control

struct	jvirt_barray_control

Macros
#define	JPEG_INTERNALS

#define	AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */

#define	ALIGN_TYPE double

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

Typedefs
typedef union small_pool_struct *	small_pool_ptr

typedef union small_pool_struct	small_pool_hdr

typedef union large_pool_struct *	large_pool_ptr

typedef union large_pool_struct	large_pool_hdr

typedef my_memory_mgr *	my_mem_ptr

Functions
static void	out_of_memory (j_common_ptr cinfo, int which)

static void *	alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)

static void *	alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)

static JSAMPARRAY	alloc_sarray (j_common_ptr cinfo, int pool_id, JDIMENSION samplesperrow, JDIMENSION numrows)

static JBLOCKARRAY	alloc_barray (j_common_ptr cinfo, int pool_id, JDIMENSION blocksperrow, JDIMENSION numrows)

static jvirt_sarray_ptr	request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero, JDIMENSION samplesperrow, JDIMENSION numrows, JDIMENSION maxaccess)

static jvirt_barray_ptr	request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero, JDIMENSION blocksperrow, JDIMENSION numrows, JDIMENSION maxaccess)

static void	realize_virt_arrays (j_common_ptr cinfo)

static void	do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)

static void	do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)

static JSAMPARRAY	access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr, JDIMENSION start_row, JDIMENSION num_rows, boolean writable)

static JBLOCKARRAY	access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr, JDIMENSION start_row, JDIMENSION num_rows, boolean writable)

static void	free_pool (j_common_ptr cinfo, int pool_id)

static void	self_destruct (j_common_ptr cinfo)

void	jinit_memory_mgr (j_common_ptr cinfo)

Variables
static const size_t	first_pool_slop [2]

static const size_t	extra_pool_slop [2]

Macro Definition Documentation

#define JPEG_INTERNALS

#define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */

#define ALIGN_TYPE double

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

Typedef Documentation

typedef union small_pool_struct* small_pool_ptr

typedef union small_pool_struct small_pool_hdr

typedef union large_pool_struct* large_pool_ptr

typedef union large_pool_struct large_pool_hdr

typedef my_memory_mgr* my_mem_ptr

Function Documentation

static void out_of_memory	(	j_common_ptr	cinfo,
		int	which
	)

static

 {
 #ifdef MEM_STATS
   cinfo->err->trace_level = 2;  /* force self_destruct to report stats */
 #endif
   ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
 }

static void* alloc_small	(	j_common_ptr	cinfo,
		int	pool_id,
		size_t	sizeofobject
	)

static

 {
   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;
 }

static void* alloc_large	(	j_common_ptr	cinfo,
		int	pool_id,
		size_t	sizeofobject
	)

static

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

static JSAMPARRAY alloc_sarray	(	j_common_ptr	cinfo,
		int	pool_id,
		JDIMENSION	samplesperrow,
		JDIMENSION	numrows
	)

static

 {
   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;
 }

static JBLOCKARRAY alloc_barray	(	j_common_ptr	cinfo,
		int	pool_id,
		JDIMENSION	blocksperrow,
		JDIMENSION	numrows
	)

static

 {
   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;
 }

static jvirt_sarray_ptr request_virt_sarray	(	j_common_ptr	cinfo,
		int	pool_id,
		boolean	pre_zero,
		JDIMENSION	samplesperrow,
		JDIMENSION	numrows,
		JDIMENSION	maxaccess
	)

static

 {
   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;
 }

static jvirt_barray_ptr request_virt_barray	(	j_common_ptr	cinfo,
		int	pool_id,
		boolean	pre_zero,
		JDIMENSION	blocksperrow,
		JDIMENSION	numrows,
		JDIMENSION	maxaccess
	)

static

 {
   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;
 }

static void realize_virt_arrays ( j_common_ptr cinfo )

static

 {
   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;
     }
   }
 }

static void do_sarray_io	(	j_common_ptr	cinfo,
		jvirt_sarray_ptr	ptr,
		boolean	writing
	)

static

 {
   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 FAR *) ptr->mem_buffer[i],
                         file_offset, byte_count);
     else
       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
                        (void FAR *) ptr->mem_buffer[i],
                        file_offset, byte_count);
     file_offset += byte_count;
   }
 }

static void do_barray_io	(	j_common_ptr	cinfo,
		jvirt_barray_ptr	ptr,
		boolean	writing
	)

static

 {
   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 FAR *) ptr->mem_buffer[i],
                         file_offset, byte_count);
     else
       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
                        (void FAR *) ptr->mem_buffer[i],
                        file_offset, byte_count);
     file_offset += byte_count;
   }
 }

static JSAMPARRAY access_virt_sarray	(	j_common_ptr	cinfo,
		jvirt_sarray_ptr	ptr,
		JDIMENSION	start_row,
		JDIMENSION	num_rows,
		boolean	writable
	)

static

 {
   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 FAR *) 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);
 }

static JBLOCKARRAY access_virt_barray	(	j_common_ptr	cinfo,
		jvirt_barray_ptr	ptr,
		JDIMENSION	start_row,
		JDIMENSION	num_rows,
		boolean	writable
	)

static

 {
   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 FAR *) 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);
 }

static void free_pool	(	j_common_ptr	cinfo,
		int	pool_id
	)

static

 {
   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 FAR *) 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;
   }
 }

static void self_destruct ( j_common_ptr cinfo )

static

 {
   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 */
 }

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;
 
   /* Make MAX_ALLOC_CHUNK accessible to other modules */
   mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
 
   /* 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
 
 }

Variable Documentation

const size_t first_pool_slop[2]

static

Initial value:

const size_t extra_pool_slop[2]

static

Initial value:

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