4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
8 * This file contains the JPEG system-independent memory management
9 * routines. This code is usable across a wide variety of machines; most
10 * of the system dependencies have been isolated in a separate file.
11 * The major functions provided here are:
12 * * pool-based allocation and freeing of memory;
13 * * policy decisions about how to divide available memory among the
15 * * control logic for swapping virtual arrays between main memory and
17 * The separate system-dependent file provides the actual backing-storage
18 * access code, and it contains the policy decision about how much total
20 * This file is system-dependent in the sense that some of its functions
21 * are unnecessary in some systems. For example, if there is enough virtual
22 * memory so that backing storage will never be used, much of the virtual
23 * array control logic could be removed. (Of course, if you have that much
24 * memory then you shouldn't care about a little bit of unused code...)
27 #define JPEG_INTERNALS
28 #define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */
30 #define _CRT_SECURE_NO_WARNINGS
34 #include "jmemsys.h" /* import the system-dependent declarations */
37 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare getenv() */
38 extern char * getenv JPP((const char * name));
44 * Some important notes:
45 * The allocation routines provided here must never return NULL.
46 * They should exit to error_exit if unsuccessful.
48 * It's not a good idea to try to merge the sarray and barray routines,
49 * even though they are textually almost the same, because samples are
50 * usually stored as bytes while coefficients are shorts or ints. Thus,
51 * in machines where byte pointers have a different representation from
52 * word pointers, the resulting machine code could not be the same.
57 * Many machines require storage alignment: longs must start on 4-byte
58 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
59 * always returns pointers that are multiples of the worst-case alignment
60 * requirement, and we had better do so too.
61 * There isn't any really portable way to determine the worst-case alignment
62 * requirement. This module assumes that the alignment requirement is
63 * multiples of sizeof(ALIGN_TYPE).
64 * By default, we define ALIGN_TYPE as double. This is necessary on some
65 * workstations (where doubles really do need 8-byte alignment) and will work
66 * fine on nearly everything. If your machine has lesser alignment needs,
67 * you can save a few bytes by making ALIGN_TYPE smaller.
68 * The only place I know of where this will NOT work is certain Macintosh
69 * 680x0 compilers that define double as a 10-byte IEEE extended float.
70 * Doing 10-byte alignment is counterproductive because longwords won't be
71 * aligned well. Put "#define ALIGN_TYPE long" in jconfig.h if you have
75 #ifndef ALIGN_TYPE /* so can override from jconfig.h */
76 #define ALIGN_TYPE double
81 * We allocate objects from "pools", where each pool is gotten with a single
82 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
83 * overhead within a pool, except for alignment padding. Each pool has a
84 * header with a link to the next pool of the same class.
85 * Small and large pool headers are identical except that the latter's
86 * link pointer must be FAR on 80x86 machines.
87 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
88 * field. This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
89 * of the alignment requirement of ALIGN_TYPE.
92 typedef union small_pool_struct * small_pool_ptr;
94 typedef union small_pool_struct {
96 small_pool_ptr next; /* next in list of pools */
97 size_t bytes_used; /* how many bytes already used within pool */
98 size_t bytes_left; /* bytes still available in this pool */
100 ALIGN_TYPE dummy; /* included in union to ensure alignment */
103 typedef union large_pool_struct FAR * large_pool_ptr;
105 typedef union large_pool_struct {
107 large_pool_ptr next; /* next in list of pools */
108 size_t bytes_used; /* how many bytes already used within pool */
109 size_t bytes_left; /* bytes still available in this pool */
111 ALIGN_TYPE dummy; /* included in union to ensure alignment */
116 * Here is the full definition of a memory manager object.
120 struct jpeg_memory_mgr pub; /* public fields */
122 /* Each pool identifier (lifetime class) names a linked list of pools. */
123 small_pool_ptr small_list[JPOOL_NUMPOOLS];
124 large_pool_ptr large_list[JPOOL_NUMPOOLS];
126 /* Since we only have one lifetime class of virtual arrays, only one
127 * linked list is necessary (for each datatype). Note that the virtual
128 * array control blocks being linked together are actually stored somewhere
129 * in the small-pool list.
131 jvirt_sarray_ptr virt_sarray_list;
132 jvirt_barray_ptr virt_barray_list;
134 /* This counts total space obtained from jpeg_get_small/large */
135 long total_space_allocated;
137 /* alloc_sarray and alloc_barray set this value for use by virtual
140 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
143 typedef my_memory_mgr * my_mem_ptr;
147 * The control blocks for virtual arrays.
148 * Note that these blocks are allocated in the "small" pool area.
149 * System-dependent info for the associated backing store (if any) is hidden
150 * inside the backing_store_info struct.
153 struct jvirt_sarray_control {
154 JSAMPARRAY mem_buffer; /* => the in-memory buffer */
155 JDIMENSION rows_in_array; /* total virtual array height */
156 JDIMENSION samplesperrow; /* width of array (and of memory buffer) */
157 JDIMENSION maxaccess; /* max rows accessed by access_virt_sarray */
158 JDIMENSION rows_in_mem; /* height of memory buffer */
159 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
160 JDIMENSION cur_start_row; /* first logical row # in the buffer */
161 JDIMENSION first_undef_row; /* row # of first uninitialized row */
162 boolean pre_zero; /* pre-zero mode requested? */
163 boolean dirty; /* do current buffer contents need written? */
164 boolean b_s_open; /* is backing-store data valid? */
165 jvirt_sarray_ptr next; /* link to next virtual sarray control block */
166 backing_store_info b_s_info; /* System-dependent control info */
169 struct jvirt_barray_control {
170 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
171 JDIMENSION rows_in_array; /* total virtual array height */
172 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
173 JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */
174 JDIMENSION rows_in_mem; /* height of memory buffer */
175 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
176 JDIMENSION cur_start_row; /* first logical row # in the buffer */
177 JDIMENSION first_undef_row; /* row # of first uninitialized row */
178 boolean pre_zero; /* pre-zero mode requested? */
179 boolean dirty; /* do current buffer contents need written? */
180 boolean b_s_open; /* is backing-store data valid? */
181 jvirt_barray_ptr next; /* link to next virtual barray control block */
182 backing_store_info b_s_info; /* System-dependent control info */
186 #ifdef MEM_STATS /* optional extra stuff for statistics */
189 print_mem_stats (j_common_ptr cinfo, int pool_id)
191 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
192 small_pool_ptr shdr_ptr;
193 large_pool_ptr lhdr_ptr;
195 /* Since this is only a debugging stub, we can cheat a little by using
196 * fprintf directly rather than going through the trace message code.
197 * This is helpful because message parm array can't handle longs.
199 fprintf(stderr, "Freeing pool %d, total space = %ld\n",
200 pool_id, mem->total_space_allocated);
202 for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
203 lhdr_ptr = lhdr_ptr->hdr.next) {
204 fprintf(stderr, " Large chunk used %ld\n",
205 (long) lhdr_ptr->hdr.bytes_used);
208 for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
209 shdr_ptr = shdr_ptr->hdr.next) {
210 fprintf(stderr, " Small chunk used %ld free %ld\n",
211 (long) shdr_ptr->hdr.bytes_used,
212 (long) shdr_ptr->hdr.bytes_left);
216 #endif /* MEM_STATS */
220 out_of_memory (j_common_ptr cinfo, int which)
221 /* Report an out-of-memory error and stop execution */
222 /* If we compiled MEM_STATS support, report alloc requests before dying */
225 cinfo->err->trace_level = 2; /* force self_destruct to report stats */
227 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
232 * Allocation of "small" objects.
234 * For these, we use pooled storage. When a new pool must be created,
235 * we try to get enough space for the current request plus a "slop" factor,
236 * where the slop will be the amount of leftover space in the new pool.
237 * The speed vs. space tradeoff is largely determined by the slop values.
238 * A different slop value is provided for each pool class (lifetime),
239 * and we also distinguish the first pool of a class from later ones.
240 * NOTE: the values given work fairly well on both 16- and 32-bit-int
241 * machines, but may be too small if longs are 64 bits or more.
244 static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
246 1600, /* first PERMANENT pool */
247 16000 /* first IMAGE pool */
250 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
252 0, /* additional PERMANENT pools */
253 5000 /* additional IMAGE pools */
256 #define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
260 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
261 /* Allocate a "small" object */
263 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
264 small_pool_ptr hdr_ptr, prev_hdr_ptr;
266 size_t odd_bytes, min_request, slop;
268 /* Check for unsatisfiable request (do now to ensure no overflow below) */
269 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
270 out_of_memory(cinfo, 1); /* request exceeds malloc's ability */
272 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
273 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
275 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
277 /* See if space is available in any existing pool */
278 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
279 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
281 hdr_ptr = mem->small_list[pool_id];
282 while (hdr_ptr != NULL) {
283 if (hdr_ptr->hdr.bytes_left >= sizeofobject)
284 break; /* found pool with enough space */
285 prev_hdr_ptr = hdr_ptr;
286 hdr_ptr = hdr_ptr->hdr.next;
289 /* Time to make a new pool? */
290 if (hdr_ptr == NULL) {
291 /* min_request is what we need now, slop is what will be leftover */
292 min_request = sizeofobject + SIZEOF(small_pool_hdr);
293 if (prev_hdr_ptr == NULL) /* first pool in class? */
294 slop = first_pool_slop[pool_id];
296 slop = extra_pool_slop[pool_id];
297 /* Don't ask for more than MAX_ALLOC_CHUNK */
298 if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
299 slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
300 /* Try to get space, if fail reduce slop and try again */
302 hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
306 if (slop < MIN_SLOP) /* give up when it gets real small */
307 out_of_memory(cinfo, 2); /* jpeg_get_small failed */
309 mem->total_space_allocated += min_request + slop;
310 /* Success, initialize the new pool header and add to end of list */
311 hdr_ptr->hdr.next = NULL;
312 hdr_ptr->hdr.bytes_used = 0;
313 hdr_ptr->hdr.bytes_left = sizeofobject + slop;
314 if (prev_hdr_ptr == NULL) /* first pool in class? */
315 mem->small_list[pool_id] = hdr_ptr;
317 prev_hdr_ptr->hdr.next = hdr_ptr;
320 /* OK, allocate the object from the current pool */
321 data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
322 data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
323 hdr_ptr->hdr.bytes_used += sizeofobject;
324 hdr_ptr->hdr.bytes_left -= sizeofobject;
326 return (void *) data_ptr;
331 * Allocation of "large" objects.
333 * The external semantics of these are the same as "small" objects,
334 * except that FAR pointers are used on 80x86. However the pool
335 * management heuristics are quite different. We assume that each
336 * request is large enough that it may as well be passed directly to
337 * jpeg_get_large; the pool management just links everything together
338 * so that we can free it all on demand.
339 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
340 * structures. The routines that create these structures (see below)
341 * deliberately bunch rows together to ensure a large request size.
344 METHODDEF(void FAR *)
345 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
346 /* Allocate a "large" object */
348 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
349 large_pool_ptr hdr_ptr;
352 /* Check for unsatisfiable request (do now to ensure no overflow below) */
353 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
354 out_of_memory(cinfo, 3); /* request exceeds malloc's ability */
356 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
357 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
359 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
361 /* Always make a new pool */
362 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
363 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
365 hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
366 SIZEOF(large_pool_hdr));
368 out_of_memory(cinfo, 4); /* jpeg_get_large failed */
369 mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);
371 /* Success, initialize the new pool header and add to list */
372 hdr_ptr->hdr.next = mem->large_list[pool_id];
373 /* We maintain space counts in each pool header for statistical purposes,
374 * even though they are not needed for allocation.
376 hdr_ptr->hdr.bytes_used = sizeofobject;
377 hdr_ptr->hdr.bytes_left = 0;
378 mem->large_list[pool_id] = hdr_ptr;
380 return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
385 * Creation of 2-D sample arrays.
386 * The pointers are in near heap, the samples themselves in FAR heap.
388 * To minimize allocation overhead and to allow I/O of large contiguous
389 * blocks, we allocate the sample rows in groups of as many rows as possible
390 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
391 * NB: the virtual array control routines, later in this file, know about
392 * this chunking of rows. The rowsperchunk value is left in the mem manager
393 * object so that it can be saved away if this sarray is the workspace for
397 METHODDEF(JSAMPARRAY)
398 alloc_sarray (j_common_ptr cinfo, int pool_id,
399 JDIMENSION samplesperrow, JDIMENSION numrows)
400 /* Allocate a 2-D sample array */
402 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
405 JDIMENSION rowsperchunk, currow, i;
408 /* Calculate max # of rows allowed in one allocation chunk */
409 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
410 ((long) samplesperrow * SIZEOF(JSAMPLE));
412 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
413 if (ltemp < (long) numrows)
414 rowsperchunk = (JDIMENSION) ltemp;
416 rowsperchunk = numrows;
417 mem->last_rowsperchunk = rowsperchunk;
419 /* Get space for row pointers (small object) */
420 result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
421 (size_t) (numrows * SIZEOF(JSAMPROW)));
423 /* Get the rows themselves (large objects) */
425 while (currow < numrows) {
426 rowsperchunk = MIN(rowsperchunk, numrows - currow);
427 workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
428 (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
430 for (i = rowsperchunk; i > 0; i--) {
431 result[currow++] = workspace;
432 workspace += samplesperrow;
441 * Creation of 2-D coefficient-block arrays.
442 * This is essentially the same as the code for sample arrays, above.
445 METHODDEF(JBLOCKARRAY)
446 alloc_barray (j_common_ptr cinfo, int pool_id,
447 JDIMENSION blocksperrow, JDIMENSION numrows)
448 /* Allocate a 2-D coefficient-block array */
450 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
453 JDIMENSION rowsperchunk, currow, i;
456 /* Calculate max # of rows allowed in one allocation chunk */
457 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
458 ((long) blocksperrow * SIZEOF(JBLOCK));
460 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
461 if (ltemp < (long) numrows)
462 rowsperchunk = (JDIMENSION) ltemp;
464 rowsperchunk = numrows;
465 mem->last_rowsperchunk = rowsperchunk;
467 /* Get space for row pointers (small object) */
468 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
469 (size_t) (numrows * SIZEOF(JBLOCKROW)));
471 /* Get the rows themselves (large objects) */
473 while (currow < numrows) {
474 rowsperchunk = MIN(rowsperchunk, numrows - currow);
475 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
476 (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
478 for (i = rowsperchunk; i > 0; i--) {
479 result[currow++] = workspace;
480 workspace += blocksperrow;
489 * About virtual array management:
491 * The above "normal" array routines are only used to allocate strip buffers
492 * (as wide as the image, but just a few rows high). Full-image-sized buffers
493 * are handled as "virtual" arrays. The array is still accessed a strip at a
494 * time, but the memory manager must save the whole array for repeated
495 * accesses. The intended implementation is that there is a strip buffer in
496 * memory (as high as is possible given the desired memory limit), plus a
497 * backing file that holds the rest of the array.
499 * The request_virt_array routines are told the total size of the image and
500 * the maximum number of rows that will be accessed at once. The in-memory
501 * buffer must be at least as large as the maxaccess value.
503 * The request routines create control blocks but not the in-memory buffers.
504 * That is postponed until realize_virt_arrays is called. At that time the
505 * total amount of space needed is known (approximately, anyway), so free
506 * memory can be divided up fairly.
508 * The access_virt_array routines are responsible for making a specific strip
509 * area accessible (after reading or writing the backing file, if necessary).
510 * Note that the access routines are told whether the caller intends to modify
511 * the accessed strip; during a read-only pass this saves having to rewrite
512 * data to disk. The access routines are also responsible for pre-zeroing
513 * any newly accessed rows, if pre-zeroing was requested.
515 * In current usage, the access requests are usually for nonoverlapping
516 * strips; that is, successive access start_row numbers differ by exactly
517 * num_rows = maxaccess. This means we can get good performance with simple
518 * buffer dump/reload logic, by making the in-memory buffer be a multiple
519 * of the access height; then there will never be accesses across bufferload
520 * boundaries. The code will still work with overlapping access requests,
521 * but it doesn't handle bufferload overlaps very efficiently.
525 METHODDEF(jvirt_sarray_ptr)
526 request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
527 JDIMENSION samplesperrow, JDIMENSION numrows,
528 JDIMENSION maxaccess)
529 /* Request a virtual 2-D sample array */
531 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
532 jvirt_sarray_ptr result;
534 /* Only IMAGE-lifetime virtual arrays are currently supported */
535 if (pool_id != JPOOL_IMAGE)
536 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
538 /* get control block */
539 result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
540 SIZEOF(struct jvirt_sarray_control));
542 result->mem_buffer = NULL; /* marks array not yet realized */
543 result->rows_in_array = numrows;
544 result->samplesperrow = samplesperrow;
545 result->maxaccess = maxaccess;
546 result->pre_zero = pre_zero;
547 result->b_s_open = FALSE; /* no associated backing-store object */
548 result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
549 mem->virt_sarray_list = result;
555 METHODDEF(jvirt_barray_ptr)
556 request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
557 JDIMENSION blocksperrow, JDIMENSION numrows,
558 JDIMENSION maxaccess)
559 /* Request a virtual 2-D coefficient-block array */
561 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
562 jvirt_barray_ptr result;
564 /* Only IMAGE-lifetime virtual arrays are currently supported */
565 if (pool_id != JPOOL_IMAGE)
566 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
568 /* get control block */
569 result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
570 SIZEOF(struct jvirt_barray_control));
572 result->mem_buffer = NULL; /* marks array not yet realized */
573 result->rows_in_array = numrows;
574 result->blocksperrow = blocksperrow;
575 result->maxaccess = maxaccess;
576 result->pre_zero = pre_zero;
577 result->b_s_open = FALSE; /* no associated backing-store object */
578 result->next = mem->virt_barray_list; /* add to list of virtual arrays */
579 mem->virt_barray_list = result;
586 realize_virt_arrays (j_common_ptr cinfo)
587 /* Allocate the in-memory buffers for any unrealized virtual arrays */
589 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
590 long space_per_minheight, maximum_space, avail_mem;
591 long minheights, max_minheights;
592 jvirt_sarray_ptr sptr;
593 jvirt_barray_ptr bptr;
595 /* Compute the minimum space needed (maxaccess rows in each buffer)
596 * and the maximum space needed (full image height in each buffer).
597 * These may be of use to the system-dependent jpeg_mem_available routine.
599 space_per_minheight = 0;
601 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
602 if (sptr->mem_buffer == NULL) { /* if not realized yet */
603 space_per_minheight += (long) sptr->maxaccess *
604 (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
605 maximum_space += (long) sptr->rows_in_array *
606 (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
609 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
610 if (bptr->mem_buffer == NULL) { /* if not realized yet */
611 space_per_minheight += (long) bptr->maxaccess *
612 (long) bptr->blocksperrow * SIZEOF(JBLOCK);
613 maximum_space += (long) bptr->rows_in_array *
614 (long) bptr->blocksperrow * SIZEOF(JBLOCK);
618 if (space_per_minheight <= 0)
619 return; /* no unrealized arrays, no work */
621 /* Determine amount of memory to actually use; this is system-dependent. */
622 avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
623 mem->total_space_allocated);
625 /* If the maximum space needed is available, make all the buffers full
626 * height; otherwise parcel it out with the same number of minheights
629 if (avail_mem >= maximum_space)
630 max_minheights = 1000000000L;
632 max_minheights = avail_mem / space_per_minheight;
633 /* If there doesn't seem to be enough space, try to get the minimum
634 * anyway. This allows a "stub" implementation of jpeg_mem_available().
636 if (max_minheights <= 0)
640 /* Allocate the in-memory buffers and initialize backing store as needed. */
642 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
643 if (sptr->mem_buffer == NULL) { /* if not realized yet */
644 minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
645 if (minheights <= max_minheights) {
646 /* This buffer fits in memory */
647 sptr->rows_in_mem = sptr->rows_in_array;
649 /* It doesn't fit in memory, create backing store. */
650 sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
651 jpeg_open_backing_store(cinfo, & sptr->b_s_info,
652 (long) sptr->rows_in_array *
653 (long) sptr->samplesperrow *
654 (long) SIZEOF(JSAMPLE));
655 sptr->b_s_open = TRUE;
657 sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
658 sptr->samplesperrow, sptr->rows_in_mem);
659 sptr->rowsperchunk = mem->last_rowsperchunk;
660 sptr->cur_start_row = 0;
661 sptr->first_undef_row = 0;
666 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
667 if (bptr->mem_buffer == NULL) { /* if not realized yet */
668 minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
669 if (minheights <= max_minheights) {
670 /* This buffer fits in memory */
671 bptr->rows_in_mem = bptr->rows_in_array;
673 /* It doesn't fit in memory, create backing store. */
674 bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
675 jpeg_open_backing_store(cinfo, & bptr->b_s_info,
676 (long) bptr->rows_in_array *
677 (long) bptr->blocksperrow *
678 (long) SIZEOF(JBLOCK));
679 bptr->b_s_open = TRUE;
681 bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
682 bptr->blocksperrow, bptr->rows_in_mem);
683 bptr->rowsperchunk = mem->last_rowsperchunk;
684 bptr->cur_start_row = 0;
685 bptr->first_undef_row = 0;
693 do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
694 /* Do backing store read or write of a virtual sample array */
696 long bytesperrow, file_offset, byte_count, rows, thisrow, i;
698 bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
699 file_offset = ptr->cur_start_row * bytesperrow;
700 /* Loop to read or write each allocation chunk in mem_buffer */
701 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
702 /* One chunk, but check for short chunk at end of buffer */
703 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
704 /* Transfer no more than is currently defined */
705 thisrow = (long) ptr->cur_start_row + i;
706 rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
707 /* Transfer no more than fits in file */
708 rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
709 if (rows <= 0) /* this chunk might be past end of file! */
711 byte_count = rows * bytesperrow;
713 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
714 (void FAR *) ptr->mem_buffer[i],
715 file_offset, byte_count);
717 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
718 (void FAR *) ptr->mem_buffer[i],
719 file_offset, byte_count);
720 file_offset += byte_count;
726 do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
727 /* Do backing store read or write of a virtual coefficient-block array */
729 long bytesperrow, file_offset, byte_count, rows, thisrow, i;
731 bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
732 file_offset = ptr->cur_start_row * bytesperrow;
733 /* Loop to read or write each allocation chunk in mem_buffer */
734 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
735 /* One chunk, but check for short chunk at end of buffer */
736 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
737 /* Transfer no more than is currently defined */
738 thisrow = (long) ptr->cur_start_row + i;
739 rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
740 /* Transfer no more than fits in file */
741 rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
742 if (rows <= 0) /* this chunk might be past end of file! */
744 byte_count = rows * bytesperrow;
746 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
747 (void FAR *) ptr->mem_buffer[i],
748 file_offset, byte_count);
750 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
751 (void FAR *) ptr->mem_buffer[i],
752 file_offset, byte_count);
753 file_offset += byte_count;
758 METHODDEF(JSAMPARRAY)
759 access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
760 JDIMENSION start_row, JDIMENSION num_rows,
762 /* Access the part of a virtual sample array starting at start_row */
763 /* and extending for num_rows rows. writable is true if */
764 /* caller intends to modify the accessed area. */
766 JDIMENSION end_row = start_row + num_rows;
767 JDIMENSION undef_row;
769 /* debugging check */
770 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
771 ptr->mem_buffer == NULL)
772 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
774 /* Make the desired part of the virtual array accessible */
775 if (start_row < ptr->cur_start_row ||
776 end_row > ptr->cur_start_row+ptr->rows_in_mem) {
778 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
779 /* Flush old buffer contents if necessary */
781 do_sarray_io(cinfo, ptr, TRUE);
784 /* Decide what part of virtual array to access.
785 * Algorithm: if target address > current window, assume forward scan,
786 * load starting at target address. If target address < current window,
787 * assume backward scan, load so that target area is top of window.
788 * Note that when switching from forward write to forward read, will have
789 * start_row = 0, so the limiting case applies and we load from 0 anyway.
791 if (start_row > ptr->cur_start_row) {
792 ptr->cur_start_row = start_row;
794 /* use long arithmetic here to avoid overflow & unsigned problems */
797 ltemp = (long) end_row - (long) ptr->rows_in_mem;
799 ltemp = 0; /* don't fall off front end of file */
800 ptr->cur_start_row = (JDIMENSION) ltemp;
802 /* Read in the selected part of the array.
803 * During the initial write pass, we will do no actual read
804 * because the selected part is all undefined.
806 do_sarray_io(cinfo, ptr, FALSE);
808 /* Ensure the accessed part of the array is defined; prezero if needed.
809 * To improve locality of access, we only prezero the part of the array
810 * that the caller is about to access, not the entire in-memory array.
812 if (ptr->first_undef_row < end_row) {
813 if (ptr->first_undef_row < start_row) {
814 if (writable) /* writer skipped over a section of array */
815 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
816 undef_row = start_row; /* but reader is allowed to read ahead */
818 undef_row = ptr->first_undef_row;
821 ptr->first_undef_row = end_row;
823 size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
824 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
825 end_row -= ptr->cur_start_row;
826 while (undef_row < end_row) {
827 jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
831 if (! writable) /* reader looking at undefined data */
832 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
835 /* Flag the buffer dirty if caller will write in it */
838 /* Return address of proper part of the buffer */
839 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
843 METHODDEF(JBLOCKARRAY)
844 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
845 JDIMENSION start_row, JDIMENSION num_rows,
847 /* Access the part of a virtual block array starting at start_row */
848 /* and extending for num_rows rows. writable is true if */
849 /* caller intends to modify the accessed area. */
851 JDIMENSION end_row = start_row + num_rows;
852 JDIMENSION undef_row;
854 /* debugging check */
855 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
856 ptr->mem_buffer == NULL)
857 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
859 /* Make the desired part of the virtual array accessible */
860 if (start_row < ptr->cur_start_row ||
861 end_row > ptr->cur_start_row+ptr->rows_in_mem) {
863 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
864 /* Flush old buffer contents if necessary */
866 do_barray_io(cinfo, ptr, TRUE);
869 /* Decide what part of virtual array to access.
870 * Algorithm: if target address > current window, assume forward scan,
871 * load starting at target address. If target address < current window,
872 * assume backward scan, load so that target area is top of window.
873 * Note that when switching from forward write to forward read, will have
874 * start_row = 0, so the limiting case applies and we load from 0 anyway.
876 if (start_row > ptr->cur_start_row) {
877 ptr->cur_start_row = start_row;
879 /* use long arithmetic here to avoid overflow & unsigned problems */
882 ltemp = (long) end_row - (long) ptr->rows_in_mem;
884 ltemp = 0; /* don't fall off front end of file */
885 ptr->cur_start_row = (JDIMENSION) ltemp;
887 /* Read in the selected part of the array.
888 * During the initial write pass, we will do no actual read
889 * because the selected part is all undefined.
891 do_barray_io(cinfo, ptr, FALSE);
893 /* Ensure the accessed part of the array is defined; prezero if needed.
894 * To improve locality of access, we only prezero the part of the array
895 * that the caller is about to access, not the entire in-memory array.
897 if (ptr->first_undef_row < end_row) {
898 if (ptr->first_undef_row < start_row) {
899 if (writable) /* writer skipped over a section of array */
900 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
901 undef_row = start_row; /* but reader is allowed to read ahead */
903 undef_row = ptr->first_undef_row;
906 ptr->first_undef_row = end_row;
908 size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
909 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
910 end_row -= ptr->cur_start_row;
911 while (undef_row < end_row) {
912 jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
916 if (! writable) /* reader looking at undefined data */
917 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
920 /* Flag the buffer dirty if caller will write in it */
923 /* Return address of proper part of the buffer */
924 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
929 * Release all objects belonging to a specified pool.
933 free_pool (j_common_ptr cinfo, int pool_id)
935 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
936 small_pool_ptr shdr_ptr;
937 large_pool_ptr lhdr_ptr;
940 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
941 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
944 if (cinfo->err->trace_level > 1)
945 print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
948 /* If freeing IMAGE pool, close any virtual arrays first */
949 if (pool_id == JPOOL_IMAGE) {
950 jvirt_sarray_ptr sptr;
951 jvirt_barray_ptr bptr;
953 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
954 if (sptr->b_s_open) { /* there may be no backing store */
955 sptr->b_s_open = FALSE; /* prevent recursive close if error */
956 (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
959 mem->virt_sarray_list = NULL;
960 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
961 if (bptr->b_s_open) { /* there may be no backing store */
962 bptr->b_s_open = FALSE; /* prevent recursive close if error */
963 (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
966 mem->virt_barray_list = NULL;
969 /* Release large objects */
970 lhdr_ptr = mem->large_list[pool_id];
971 mem->large_list[pool_id] = NULL;
973 while (lhdr_ptr != NULL) {
974 large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
975 space_freed = lhdr_ptr->hdr.bytes_used +
976 lhdr_ptr->hdr.bytes_left +
977 SIZEOF(large_pool_hdr);
978 jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
979 mem->total_space_allocated -= space_freed;
980 lhdr_ptr = next_lhdr_ptr;
983 /* Release small objects */
984 shdr_ptr = mem->small_list[pool_id];
985 mem->small_list[pool_id] = NULL;
987 while (shdr_ptr != NULL) {
988 small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
989 space_freed = shdr_ptr->hdr.bytes_used +
990 shdr_ptr->hdr.bytes_left +
991 SIZEOF(small_pool_hdr);
992 jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
993 mem->total_space_allocated -= space_freed;
994 shdr_ptr = next_shdr_ptr;
1000 * Close up shop entirely.
1001 * Note that this cannot be called unless cinfo->mem is non-NULL.
1005 self_destruct (j_common_ptr cinfo)
1009 /* Close all backing store, release all memory.
1010 * Releasing pools in reverse order might help avoid fragmentation
1011 * with some (brain-damaged) malloc libraries.
1013 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1014 free_pool(cinfo, pool);
1017 /* Release the memory manager control block too. */
1018 jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
1019 cinfo->mem = NULL; /* ensures I will be called only once */
1021 jpeg_mem_term(cinfo); /* system-dependent cleanup */
1026 * Memory manager initialization.
1027 * When this is called, only the error manager pointer is valid in cinfo!
1031 jinit_memory_mgr (j_common_ptr cinfo)
1038 cinfo->mem = NULL; /* for safety if init fails */
1040 /* Check for configuration errors.
1041 * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
1042 * doesn't reflect any real hardware alignment requirement.
1043 * The test is a little tricky: for X>0, X and X-1 have no one-bits
1044 * in common if and only if X is a power of 2, ie has only one one-bit.
1045 * Some compilers may give an "unreachable code" warning here; ignore it.
1047 if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
1048 ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
1049 /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
1050 * a multiple of SIZEOF(ALIGN_TYPE).
1051 * Again, an "unreachable code" warning may be ignored here.
1052 * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
1054 test_mac = (size_t) MAX_ALLOC_CHUNK;
1055 if ((long) test_mac != MAX_ALLOC_CHUNK ||
1056 (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
1057 ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
1059 max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
1061 /* Attempt to allocate memory manager's control block */
1062 mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
1065 jpeg_mem_term(cinfo); /* system-dependent cleanup */
1066 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
1069 /* OK, fill in the method pointers */
1070 mem->pub.alloc_small = alloc_small;
1071 mem->pub.alloc_large = alloc_large;
1072 mem->pub.alloc_sarray = alloc_sarray;
1073 mem->pub.alloc_barray = alloc_barray;
1074 mem->pub.request_virt_sarray = request_virt_sarray;
1075 mem->pub.request_virt_barray = request_virt_barray;
1076 mem->pub.realize_virt_arrays = realize_virt_arrays;
1077 mem->pub.access_virt_sarray = access_virt_sarray;
1078 mem->pub.access_virt_barray = access_virt_barray;
1079 mem->pub.free_pool = free_pool;
1080 mem->pub.self_destruct = self_destruct;
1082 /* Make MAX_ALLOC_CHUNK accessible to other modules */
1083 mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
1085 /* Initialize working state */
1086 mem->pub.max_memory_to_use = max_to_use;
1088 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1089 mem->small_list[pool] = NULL;
1090 mem->large_list[pool] = NULL;
1092 mem->virt_sarray_list = NULL;
1093 mem->virt_barray_list = NULL;
1095 mem->total_space_allocated = SIZEOF(my_memory_mgr);
1097 /* Declare ourselves open for business */
1098 cinfo->mem = & mem->pub;
1100 /* Check for an environment variable JPEGMEM; if found, override the
1101 * default max_memory setting from jpeg_mem_init. Note that the
1102 * surrounding application may again override this value.
1103 * If your system doesn't support getenv(), define NO_GETENV to disable
1109 if ((memenv = getenv("JPEGMEM")) != NULL) {
1112 if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
1113 if (ch == 'm' || ch == 'M')
1114 max_to_use *= 1000L;
1115 mem->pub.max_memory_to_use = max_to_use * 1000L;