ref: bea7b7bf8ccbc2bc41906517079e76fcfb31cb5a
dir: /code/jpeg-6/jmemmgr.c/
/*
* jmemmgr.c
*
* Copyright (C) 1991-1995, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains the JPEG system-independent memory management
* routines. This code is usable across a wide variety of machines; most
* of the system dependencies have been isolated in a separate file.
* The major functions provided here are:
* * pool-based allocation and freeing of memory;
* * policy decisions about how to divide available memory among the
* virtual arrays;
* * control logic for swapping virtual arrays between main memory and
* backing storage.
* The separate system-dependent file provides the actual backing-storage
* access code, and it contains the policy decision about how much total
* main memory to use.
* This file is system-dependent in the sense that some of its functions
* are unnecessary in some systems. For example, if there is enough virtual
* memory so that backing storage will never be used, much of the virtual
* array control logic could be removed. (Of course, if you have that much
* memory then you shouldn't care about a little bit of unused code...)
*/
#define JPEG_INTERNALS
#define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */
#include "jinclude.h"
#include "jpeglib.h"
#include "jmemsys.h" /* import the system-dependent declarations */
#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 FAR * 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 FAR *
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 FAR *) (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 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;
}
}
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 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;
}
}
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 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);
}
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 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);
}
/*
* 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 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;
}
}
/*
* 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
}