1 /*
2 * jmemmgr.c
3 *
4 * Copyright (C) 1991-1998, 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.
7 *
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
14 * virtual arrays;
15 * * control logic for swapping virtual arrays between main memory and
16 * backing storage.
17 * The separate system-dependent file provides the actual backing-storage
18 * access code, and it contains the policy decision about how much total
19 * main memory to use.
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...)
25 */
26
27 #define JPEG_INTERNALS
28 #define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */
29 #include "jinclude16.h"
30 #include "jpeglib16.h"
31 #include "jmemsys16.h" /* import the system-dependent declarations */
32
33 #ifndef NO_GETENV
34 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare getenv() */
35 extern char * getenv JPP((const char * name));
36 #endif
37 #endif
38
39
40 /*
41 * Some important notes:
42 * The allocation routines provided here must never return NULL.
43 * They should exit to error_exit if unsuccessful.
44 *
45 * It's not a good idea to try to merge the sarray, barray and darray
46 * routines, even though they are textually almost the same, because
47 * samples are usually stored as bytes while coefficients and differenced
48 * are shorts or ints. Thus, in machines where byte pointers have a
49 * different representation from word pointers, the resulting machine
50 * code could not be the same.
51 */
52
53
54 /*
55 * Many machines require storage alignment: longs must start on 4-byte
56 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
57 * always returns pointers that are multiples of the worst-case alignment
58 * requirement, and we had better do so too.
59 * There isn't any really portable way to determine the worst-case alignment
60 * requirement. This module assumes that the alignment requirement is
61 * multiples of sizeof(ALIGN_TYPE).
62 * By default, we define ALIGN_TYPE as double. This is necessary on some
63 * workstations (where doubles really do need 8-byte alignment) and will work
64 * fine on nearly everything. If your machine has lesser alignment needs,
65 * you can save a few bytes by making ALIGN_TYPE smaller.
66 * The only place I know of where this will NOT work is certain Macintosh
67 * 680x0 compilers that define double as a 10-byte IEEE extended float.
68 * Doing 10-byte alignment is counterproductive because longwords won't be
69 * aligned well. Put "#define ALIGN_TYPE long" in jconfig.h if you have
70 * such a compiler.
71 */
72
73 #ifndef ALIGN_TYPE /* so can override from jconfig.h */
74 #define ALIGN_TYPE double
75 #endif
76
77
78 /*
79 * We allocate objects from "pools", where each pool is gotten with a single
80 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
81 * overhead within a pool, except for alignment padding. Each pool has a
82 * header with a link to the next pool of the same class.
83 * Small and large pool headers are identical except that the latter's
84 * link pointer must be FAR on 80x86 machines.
85 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
86 * field. This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
87 * of the alignment requirement of ALIGN_TYPE.
88 */
89
90 typedef union small_pool_struct * small_pool_ptr;
91
92 typedef union small_pool_struct {
93 struct {
94 small_pool_ptr next; /* next in list of pools */
95 size_t bytes_used; /* how many bytes already used within pool */
96 size_t bytes_left; /* bytes still available in this pool */
97 } hdr;
98 ALIGN_TYPE dummy; /* included in union to ensure alignment */
99 } small_pool_hdr;
100
101 typedef union large_pool_struct FAR * large_pool_ptr;
102
103 typedef union large_pool_struct {
104 struct {
105 large_pool_ptr next; /* next in list of pools */
106 size_t bytes_used; /* how many bytes already used within pool */
107 size_t bytes_left; /* bytes still available in this pool */
108 } hdr;
109 ALIGN_TYPE dummy; /* included in union to ensure alignment */
110 } large_pool_hdr;
111
112
113 /*
114 * Here is the full definition of a memory manager object.
115 */
116
117 typedef struct {
118 struct jpeg_memory_mgr pub; /* public fields */
119
120 /* Each pool identifier (lifetime class) names a linked list of pools. */
121 small_pool_ptr small_list[JPOOL_NUMPOOLS];
122 large_pool_ptr large_list[JPOOL_NUMPOOLS];
123
124 /* Since we only have one lifetime class of virtual arrays, only one
125 * linked list is necessary (for each datatype). Note that the virtual
126 * array control blocks being linked together are actually stored somewhere
127 * in the small-pool list.
128 */
129 jvirt_sarray_ptr virt_sarray_list;
130 jvirt_barray_ptr virt_barray_list;
131
132 /* This counts total space obtained from jpeg_get_small/large */
133 long total_space_allocated;
134
135 /* alloc_sarray and alloc_barray set this value for use by virtual
136 * array routines.
137 */
138 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
139 } my_memory_mgr;
140
141 typedef my_memory_mgr * my_mem_ptr;
142
143
144 /*
145 * The control blocks for virtual arrays.
146 * Note that these blocks are allocated in the "small" pool area.
147 * System-dependent info for the associated backing store (if any) is hidden
148 * inside the backing_store_info struct.
149 */
150
151 struct jvirt_sarray_control {
152 JSAMPARRAY mem_buffer; /* => the in-memory buffer */
153 JDIMENSION rows_in_array; /* total virtual array height */
154 JDIMENSION samplesperrow; /* width of array (and of memory buffer) */
155 JDIMENSION maxaccess; /* max rows accessed by access_virt_sarray */
156 JDIMENSION rows_in_mem; /* height of memory buffer */
157 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
158 JDIMENSION cur_start_row; /* first logical row # in the buffer */
159 JDIMENSION first_undef_row; /* row # of first uninitialized row */
160 boolean pre_zero; /* pre-zero mode requested? */
161 boolean dirty; /* do current buffer contents need written? */
162 boolean b_s_open; /* is backing-store data valid? */
163 jvirt_sarray_ptr next; /* link to next virtual sarray control block */
164 backing_store_info b_s_info; /* System-dependent control info */
165 };
166
167 struct jvirt_barray_control {
168 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
169 JDIMENSION rows_in_array; /* total virtual array height */
170 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
171 JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */
172 JDIMENSION rows_in_mem; /* height of memory buffer */
173 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
174 JDIMENSION cur_start_row; /* first logical row # in the buffer */
175 JDIMENSION first_undef_row; /* row # of first uninitialized row */
176 boolean pre_zero; /* pre-zero mode requested? */
177 boolean dirty; /* do current buffer contents need written? */
178 boolean b_s_open; /* is backing-store data valid? */
179 jvirt_barray_ptr next; /* link to next virtual barray control block */
180 backing_store_info b_s_info; /* System-dependent control info */
181 };
182
183
184 #ifdef MEM_STATS /* optional extra stuff for statistics */
185
186 LOCAL(void)
print_mem_stats(j_common_ptr cinfo,int pool_id)187 print_mem_stats (j_common_ptr cinfo, int pool_id)
188 {
189 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
190 small_pool_ptr shdr_ptr;
191 large_pool_ptr lhdr_ptr;
192
193 /* Since this is only a debugging stub, we can cheat a little by using
194 * fprintf directly rather than going through the trace message code.
195 * This is helpful because message parm array can't handle longs.
196 */
197 fprintf(stderr, "Freeing pool %d, total space = %ld\n",
198 pool_id, mem->total_space_allocated);
199
200 for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
201 lhdr_ptr = lhdr_ptr->hdr.next) {
202 fprintf(stderr, " Large chunk used %ld\n",
203 (long) lhdr_ptr->hdr.bytes_used);
204 }
205
206 for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
207 shdr_ptr = shdr_ptr->hdr.next) {
208 fprintf(stderr, " Small chunk used %ld free %ld\n",
209 (long) shdr_ptr->hdr.bytes_used,
210 (long) shdr_ptr->hdr.bytes_left);
211 }
212 }
213
214 #endif /* MEM_STATS */
215
216
217 LOCAL(void)
out_of_memory(j_common_ptr cinfo,int which)218 out_of_memory (j_common_ptr cinfo, int which)
219 /* Report an out-of-memory error and stop execution */
220 /* If we compiled MEM_STATS support, report alloc requests before dying */
221 {
222 #ifdef MEM_STATS
223 cinfo->err->trace_level = 2; /* force self_destruct to report stats */
224 #endif
225 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
226 }
227
228
229 /*
230 * Allocation of "small" objects.
231 *
232 * For these, we use pooled storage. When a new pool must be created,
233 * we try to get enough space for the current request plus a "slop" factor,
234 * where the slop will be the amount of leftover space in the new pool.
235 * The speed vs. space tradeoff is largely determined by the slop values.
236 * A different slop value is provided for each pool class (lifetime),
237 * and we also distinguish the first pool of a class from later ones.
238 * NOTE: the values given work fairly well on both 16- and 32-bit-int
239 * machines, but may be too small if longs are 64 bits or more.
240 */
241
242 static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
243 {
244 1600, /* first PERMANENT pool */
245 16000 /* first IMAGE pool */
246 };
247
248 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
249 {
250 0, /* additional PERMANENT pools */
251 5000 /* additional IMAGE pools */
252 };
253
254 #define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
255
256
257 METHODDEF(void *)
alloc_small(j_common_ptr cinfo,int pool_id,size_t sizeofobject)258 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
259 /* Allocate a "small" object */
260 {
261 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
262 small_pool_ptr hdr_ptr, prev_hdr_ptr;
263 char * data_ptr;
264 size_t odd_bytes, min_request, slop;
265
266 /* Check for unsatisfiable request (do now to ensure no overflow below) */
267 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
268 out_of_memory(cinfo, 1); /* request exceeds malloc's ability */
269
270 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
271 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
272 if (odd_bytes > 0)
273 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
274
275 /* See if space is available in any existing pool */
276 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
277 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
278 prev_hdr_ptr = NULL;
279 hdr_ptr = mem->small_list[pool_id];
280 while (hdr_ptr != NULL) {
281 if (hdr_ptr->hdr.bytes_left >= sizeofobject)
282 break; /* found pool with enough space */
283 prev_hdr_ptr = hdr_ptr;
284 hdr_ptr = hdr_ptr->hdr.next;
285 }
286
287 /* Time to make a new pool? */
288 if (hdr_ptr == NULL) {
289 /* min_request is what we need now, slop is what will be leftover */
290 min_request = sizeofobject + SIZEOF(small_pool_hdr);
291 if (prev_hdr_ptr == NULL) /* first pool in class? */
292 slop = first_pool_slop[pool_id];
293 else
294 slop = extra_pool_slop[pool_id];
295 /* Don't ask for more than MAX_ALLOC_CHUNK */
296 if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
297 slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
298 /* Try to get space, if fail reduce slop and try again */
299 for (;;) {
300 hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
301 if (hdr_ptr != NULL)
302 break;
303 slop /= 2;
304 if (slop < MIN_SLOP) /* give up when it gets real small */
305 out_of_memory(cinfo, 2); /* jpeg_get_small failed */
306 }
307 mem->total_space_allocated += (long)(min_request + slop);
308 /* Success, initialize the new pool header and add to end of list */
309 hdr_ptr->hdr.next = NULL;
310 hdr_ptr->hdr.bytes_used = 0;
311 hdr_ptr->hdr.bytes_left = sizeofobject + slop;
312 if (prev_hdr_ptr == NULL) /* first pool in class? */
313 mem->small_list[pool_id] = hdr_ptr;
314 else
315 prev_hdr_ptr->hdr.next = hdr_ptr;
316 }
317
318 /* OK, allocate the object from the current pool */
319 data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
320 data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
321 hdr_ptr->hdr.bytes_used += sizeofobject;
322 hdr_ptr->hdr.bytes_left -= sizeofobject;
323
324 return (void *) data_ptr;
325 }
326
327
328 /*
329 * Allocation of "large" objects.
330 *
331 * The external semantics of these are the same as "small" objects,
332 * except that FAR pointers are used on 80x86. However the pool
333 * management heuristics are quite different. We assume that each
334 * request is large enough that it may as well be passed directly to
335 * jpeg_get_large; the pool management just links everything together
336 * so that we can free it all on demand.
337 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
338 * structures. The routines that create these structures (see below)
339 * deliberately bunch rows together to ensure a large request size.
340 */
341
342 METHODDEF(void FAR *)
alloc_large(j_common_ptr cinfo,int pool_id,size_t sizeofobject)343 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
344 /* Allocate a "large" object */
345 {
346 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
347 large_pool_ptr hdr_ptr;
348 size_t odd_bytes;
349
350 /* Check for unsatisfiable request (do now to ensure no overflow below) */
351 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
352 out_of_memory(cinfo, 3); /* request exceeds malloc's ability */
353
354 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
355 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
356 if (odd_bytes > 0)
357 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
358
359 /* Always make a new pool */
360 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
361 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
362
363 hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
364 SIZEOF(large_pool_hdr));
365 if (hdr_ptr == NULL)
366 out_of_memory(cinfo, 4); /* jpeg_get_large failed */
367 mem->total_space_allocated += (long)(sizeofobject + SIZEOF(large_pool_hdr));
368
369 /* Success, initialize the new pool header and add to list */
370 hdr_ptr->hdr.next = mem->large_list[pool_id];
371 /* We maintain space counts in each pool header for statistical purposes,
372 * even though they are not needed for allocation.
373 */
374 hdr_ptr->hdr.bytes_used = sizeofobject;
375 hdr_ptr->hdr.bytes_left = 0;
376 mem->large_list[pool_id] = hdr_ptr;
377
378 return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
379 }
380
381
382 /*
383 * Creation of 2-D sample arrays.
384 * The pointers are in near heap, the samples themselves in FAR heap.
385 *
386 * To minimize allocation overhead and to allow I/O of large contiguous
387 * blocks, we allocate the sample rows in groups of as many rows as possible
388 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
389 * NB: the virtual array control routines, later in this file, know about
390 * this chunking of rows. The rowsperchunk value is left in the mem manager
391 * object so that it can be saved away if this sarray is the workspace for
392 * a virtual array.
393 */
394
395 METHODDEF(JSAMPARRAY)
alloc_sarray(j_common_ptr cinfo,int pool_id,JDIMENSION samplesperrow,JDIMENSION numrows)396 alloc_sarray (j_common_ptr cinfo, int pool_id,
397 JDIMENSION samplesperrow, JDIMENSION numrows)
398 /* Allocate a 2-D sample array */
399 {
400 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
401 JSAMPARRAY result;
402 JSAMPROW workspace;
403 JDIMENSION rowsperchunk, currow, i;
404 size_t ltemp;
405
406 /* Calculate max # of rows allowed in one allocation chunk */
407 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
408 ((size_t) samplesperrow * SIZEOF(JSAMPLE));
409 if (ltemp <= 0)
410 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
411 if (ltemp < numrows)
412 rowsperchunk = (JDIMENSION) ltemp;
413 else
414 rowsperchunk = numrows;
415 mem->last_rowsperchunk = rowsperchunk;
416
417 /* Get space for row pointers (small object) */
418 result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
419 (size_t) (numrows * SIZEOF(JSAMPROW)));
420
421 /* Get the rows themselves (large objects) */
422 currow = 0;
423 while (currow < numrows) {
424 rowsperchunk = MIN(rowsperchunk, numrows - currow);
425 workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
426 (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
427 * SIZEOF(JSAMPLE)));
428 for (i = rowsperchunk; i > 0; i--) {
429 result[currow++] = workspace;
430 workspace += samplesperrow;
431 }
432 }
433
434 return result;
435 }
436
437
438 /*
439 * Creation of 2-D coefficient-block arrays.
440 * This is essentially the same as the code for sample arrays, above.
441 */
442
443 METHODDEF(JBLOCKARRAY)
alloc_barray(j_common_ptr cinfo,int pool_id,JDIMENSION blocksperrow,JDIMENSION numrows)444 alloc_barray (j_common_ptr cinfo, int pool_id,
445 JDIMENSION blocksperrow, JDIMENSION numrows)
446 /* Allocate a 2-D coefficient-block array */
447 {
448 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
449 JBLOCKARRAY result;
450 JBLOCKROW workspace;
451 JDIMENSION rowsperchunk, currow, i;
452 size_t ltemp;
453
454 /* Calculate max # of rows allowed in one allocation chunk */
455 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
456 ((size_t) blocksperrow * SIZEOF(JBLOCK));
457 if (ltemp <= 0)
458 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
459 if (ltemp < numrows)
460 rowsperchunk = (JDIMENSION) ltemp;
461 else
462 rowsperchunk = numrows;
463 mem->last_rowsperchunk = rowsperchunk;
464
465 /* Get space for row pointers (small object) */
466 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
467 (size_t) (numrows * SIZEOF(JBLOCKROW)));
468
469 /* Get the rows themselves (large objects) */
470 currow = 0;
471 while (currow < numrows) {
472 rowsperchunk = MIN(rowsperchunk, numrows - currow);
473 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
474 (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
475 * SIZEOF(JBLOCK)));
476 for (i = rowsperchunk; i > 0; i--) {
477 result[currow++] = workspace;
478 workspace += blocksperrow;
479 }
480 }
481
482 return result;
483 }
484
485
486 #ifdef NEED_DARRAY
487
488 /*
489 * Creation of 2-D difference arrays.
490 * This is essentially the same as the code for sample arrays, above.
491 */
492
493 METHODDEF(JDIFFARRAY)
alloc_darray(j_common_ptr cinfo,int pool_id,JDIMENSION diffsperrow,JDIMENSION numrows)494 alloc_darray (j_common_ptr cinfo, int pool_id,
495 JDIMENSION diffsperrow, JDIMENSION numrows)
496 /* Allocate a 2-D difference array */
497 {
498 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
499 JDIFFARRAY result;
500 JDIFFROW workspace;
501 JDIMENSION rowsperchunk, currow, i;
502 size_t ltemp;
503
504 /* Calculate max # of rows allowed in one allocation chunk */
505 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
506 ((size_t) diffsperrow * SIZEOF(JDIFF));
507 if (ltemp <= 0)
508 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
509 if (ltemp < numrows)
510 rowsperchunk = (JDIMENSION) ltemp;
511 else
512 rowsperchunk = numrows;
513 mem->last_rowsperchunk = rowsperchunk;
514
515 /* Get space for row pointers (small object) */
516 result = (JDIFFARRAY) alloc_small(cinfo, pool_id,
517 (size_t) (numrows * SIZEOF(JDIFFROW)));
518
519 /* Get the rows themselves (large objects) */
520 currow = 0;
521 while (currow < numrows) {
522 rowsperchunk = MIN(rowsperchunk, numrows - currow);
523 workspace = (JDIFFROW) alloc_large(cinfo, pool_id,
524 (size_t) ((size_t) rowsperchunk * (size_t) diffsperrow
525 * SIZEOF(JDIFF)));
526 for (i = rowsperchunk; i > 0; i--) {
527 result[currow++] = workspace;
528 workspace += diffsperrow;
529 }
530 }
531
532 return result;
533 }
534
535 #endif
536
537
538 /*
539 * About virtual array management:
540 *
541 * The above "normal" array routines are only used to allocate strip buffers
542 * (as wide as the image, but just a few rows high). Full-image-sized buffers
543 * are handled as "virtual" arrays. The array is still accessed a strip at a
544 * time, but the memory manager must save the whole array for repeated
545 * accesses. The intended implementation is that there is a strip buffer in
546 * memory (as high as is possible given the desired memory limit), plus a
547 * backing file that holds the rest of the array.
548 *
549 * The request_virt_array routines are told the total size of the image and
550 * the maximum number of rows that will be accessed at once. The in-memory
551 * buffer must be at least as large as the maxaccess value.
552 *
553 * The request routines create control blocks but not the in-memory buffers.
554 * That is postponed until realize_virt_arrays is called. At that time the
555 * total amount of space needed is known (approximately, anyway), so free
556 * memory can be divided up fairly.
557 *
558 * The access_virt_array routines are responsible for making a specific strip
559 * area accessible (after reading or writing the backing file, if necessary).
560 * Note that the access routines are told whether the caller intends to modify
561 * the accessed strip; during a read-only pass this saves having to rewrite
562 * data to disk. The access routines are also responsible for pre-zeroing
563 * any newly accessed rows, if pre-zeroing was requested.
564 *
565 * In current usage, the access requests are usually for nonoverlapping
566 * strips; that is, successive access start_row numbers differ by exactly
567 * num_rows = maxaccess. This means we can get good performance with simple
568 * buffer dump/reload logic, by making the in-memory buffer be a multiple
569 * of the access height; then there will never be accesses across bufferload
570 * boundaries. The code will still work with overlapping access requests,
571 * but it doesn't handle bufferload overlaps very efficiently.
572 */
573
574
575 METHODDEF(jvirt_sarray_ptr)
request_virt_sarray(j_common_ptr cinfo,int pool_id,boolean pre_zero,JDIMENSION samplesperrow,JDIMENSION numrows,JDIMENSION maxaccess)576 request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
577 JDIMENSION samplesperrow, JDIMENSION numrows,
578 JDIMENSION maxaccess)
579 /* Request a virtual 2-D sample array */
580 {
581 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
582 jvirt_sarray_ptr result;
583
584 /* Only IMAGE-lifetime virtual arrays are currently supported */
585 if (pool_id != JPOOL_IMAGE)
586 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
587
588 /* get control block */
589 result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
590 SIZEOF(struct jvirt_sarray_control));
591
592 result->mem_buffer = NULL; /* marks array not yet realized */
593 result->rows_in_array = numrows;
594 result->samplesperrow = samplesperrow;
595 result->maxaccess = maxaccess;
596 result->pre_zero = pre_zero;
597 result->b_s_open = FALSE; /* no associated backing-store object */
598 result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
599 mem->virt_sarray_list = result;
600
601 return result;
602 }
603
604
605 METHODDEF(jvirt_barray_ptr)
request_virt_barray(j_common_ptr cinfo,int pool_id,boolean pre_zero,JDIMENSION blocksperrow,JDIMENSION numrows,JDIMENSION maxaccess)606 request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
607 JDIMENSION blocksperrow, JDIMENSION numrows,
608 JDIMENSION maxaccess)
609 /* Request a virtual 2-D coefficient-block array */
610 {
611 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
612 jvirt_barray_ptr result;
613
614 /* Only IMAGE-lifetime virtual arrays are currently supported */
615 if (pool_id != JPOOL_IMAGE)
616 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
617
618 /* get control block */
619 result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
620 SIZEOF(struct jvirt_barray_control));
621
622 result->mem_buffer = NULL; /* marks array not yet realized */
623 result->rows_in_array = numrows;
624 result->blocksperrow = blocksperrow;
625 result->maxaccess = maxaccess;
626 result->pre_zero = pre_zero;
627 result->b_s_open = FALSE; /* no associated backing-store object */
628 result->next = mem->virt_barray_list; /* add to list of virtual arrays */
629 mem->virt_barray_list = result;
630
631 return result;
632 }
633
634
635 METHODDEF(void)
realize_virt_arrays(j_common_ptr cinfo)636 realize_virt_arrays (j_common_ptr cinfo)
637 /* Allocate the in-memory buffers for any unrealized virtual arrays */
638 {
639 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
640 size_t space_per_minheight, maximum_space, avail_mem;
641 size_t minheights, max_minheights;
642 jvirt_sarray_ptr sptr;
643 jvirt_barray_ptr bptr;
644
645 /* Compute the minimum space needed (maxaccess rows in each buffer)
646 * and the maximum space needed (full image height in each buffer).
647 * These may be of use to the system-dependent jpeg_mem_available routine.
648 */
649 space_per_minheight = 0;
650 maximum_space = 0;
651 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
652 if (sptr->mem_buffer == NULL) { /* if not realized yet */
653 space_per_minheight += sptr->maxaccess *
654 sptr->samplesperrow * SIZEOF(JSAMPLE);
655 maximum_space += sptr->rows_in_array *
656 sptr->samplesperrow * SIZEOF(JSAMPLE);
657 }
658 }
659 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
660 if (bptr->mem_buffer == NULL) { /* if not realized yet */
661 space_per_minheight += bptr->maxaccess *
662 bptr->blocksperrow * SIZEOF(JBLOCK);
663 maximum_space += bptr->rows_in_array *
664 bptr->blocksperrow * SIZEOF(JBLOCK);
665 }
666 }
667
668 if (space_per_minheight <= 0)
669 return; /* no unrealized arrays, no work */
670
671 /* Determine amount of memory to actually use; this is system-dependent. */
672 avail_mem = (size_t)jpeg_mem_available(cinfo, (long)space_per_minheight, (long)maximum_space,
673 mem->total_space_allocated);
674
675 /* If the maximum space needed is available, make all the buffers full
676 * height; otherwise parcel it out with the same number of minheights
677 * in each buffer.
678 */
679 if (avail_mem >= maximum_space)
680 max_minheights = 1000000000L;
681 else {
682 max_minheights = avail_mem / space_per_minheight;
683 /* If there doesn't seem to be enough space, try to get the minimum
684 * anyway. This allows a "stub" implementation of jpeg_mem_available().
685 */
686 if (max_minheights <= 0)
687 max_minheights = 1;
688 }
689
690 /* Allocate the in-memory buffers and initialize backing store as needed. */
691
692 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
693 if (sptr->mem_buffer == NULL) { /* if not realized yet */
694 minheights = (size_t)((sptr->rows_in_array - 1L) / sptr->maxaccess + 1L);
695 if (minheights <= max_minheights) {
696 /* This buffer fits in memory */
697 sptr->rows_in_mem = sptr->rows_in_array;
698 } else {
699 /* It doesn't fit in memory, create backing store. */
700 sptr->rows_in_mem = (JDIMENSION)max_minheights * sptr->maxaccess;
701 jpeg_open_backing_store(cinfo, & sptr->b_s_info,
702 (long) sptr->rows_in_array *
703 (long) sptr->samplesperrow *
704 (long) SIZEOF(JSAMPLE));
705 sptr->b_s_open = TRUE;
706 }
707 sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
708 sptr->samplesperrow, sptr->rows_in_mem);
709 sptr->rowsperchunk = mem->last_rowsperchunk;
710 sptr->cur_start_row = 0;
711 sptr->first_undef_row = 0;
712 sptr->dirty = FALSE;
713 }
714 }
715
716 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
717 if (bptr->mem_buffer == NULL) { /* if not realized yet */
718 minheights = (size_t)((bptr->rows_in_array - 1L) / bptr->maxaccess + 1L);
719 if (minheights <= max_minheights) {
720 /* This buffer fits in memory */
721 bptr->rows_in_mem = bptr->rows_in_array;
722 } else {
723 /* It doesn't fit in memory, create backing store. */
724 bptr->rows_in_mem = (JDIMENSION)max_minheights * bptr->maxaccess;
725 jpeg_open_backing_store(cinfo, & bptr->b_s_info,
726 (long) bptr->rows_in_array *
727 (long) bptr->blocksperrow *
728 (long) SIZEOF(JBLOCK));
729 bptr->b_s_open = TRUE;
730 }
731 bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
732 bptr->blocksperrow, bptr->rows_in_mem);
733 bptr->rowsperchunk = mem->last_rowsperchunk;
734 bptr->cur_start_row = 0;
735 bptr->first_undef_row = 0;
736 bptr->dirty = FALSE;
737 }
738 }
739 }
740
741
742 LOCAL(void)
do_sarray_io(j_common_ptr cinfo,jvirt_sarray_ptr ptr,boolean writing)743 do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
744 /* Do backing store read or write of a virtual sample array */
745 {
746 size_t bytesperrow, file_offset, byte_count, rows, thisrow, i;
747
748 bytesperrow = ptr->samplesperrow * SIZEOF(JSAMPLE);
749 file_offset = ptr->cur_start_row * bytesperrow;
750 /* Loop to read or write each allocation chunk in mem_buffer */
751 for (i = 0; i < ptr->rows_in_mem; i += ptr->rowsperchunk) {
752 /* One chunk, but check for short chunk at end of buffer */
753 rows = MIN(ptr->rowsperchunk, ptr->rows_in_mem - i);
754 /* Transfer no more than is currently defined */
755 thisrow = ptr->cur_start_row + i;
756 rows = MIN(rows, ptr->first_undef_row - thisrow);
757 /* Transfer no more than fits in file */
758 rows = MIN(rows, ptr->rows_in_array - thisrow);
759 if (rows <= 0) /* this chunk might be past end of file! */
760 break;
761 byte_count = rows * bytesperrow;
762 if (writing)
763 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
764 (void FAR *) ptr->mem_buffer[i],
765 (long)file_offset, (long)byte_count);
766 else
767 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
768 (void FAR *) ptr->mem_buffer[i],
769 (long)file_offset, (long)byte_count);
770 file_offset += byte_count;
771 }
772 }
773
774
775 LOCAL(void)
do_barray_io(j_common_ptr cinfo,jvirt_barray_ptr ptr,boolean writing)776 do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
777 /* Do backing store read or write of a virtual coefficient-block array */
778 {
779 size_t bytesperrow, file_offset, byte_count, rows, thisrow, i;
780
781 bytesperrow = ptr->blocksperrow * SIZEOF(JBLOCK);
782 file_offset = ptr->cur_start_row * bytesperrow;
783 /* Loop to read or write each allocation chunk in mem_buffer */
784 for (i = 0; i < ptr->rows_in_mem; i += ptr->rowsperchunk) {
785 /* One chunk, but check for short chunk at end of buffer */
786 rows = MIN(ptr->rowsperchunk, ptr->rows_in_mem - i);
787 /* Transfer no more than is currently defined */
788 thisrow = ptr->cur_start_row + i;
789 rows = MIN(rows, ptr->first_undef_row - thisrow);
790 /* Transfer no more than fits in file */
791 rows = MIN(rows, ptr->rows_in_array - thisrow);
792 if (rows <= 0) /* this chunk might be past end of file! */
793 break;
794 byte_count = rows * bytesperrow;
795 if (writing)
796 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
797 (void FAR *) ptr->mem_buffer[i],
798 (long)file_offset, (long)byte_count);
799 else
800 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
801 (void FAR *) ptr->mem_buffer[i],
802 (long)file_offset, (long)byte_count);
803 file_offset += byte_count;
804 }
805 }
806
807
808 METHODDEF(JSAMPARRAY)
access_virt_sarray(j_common_ptr cinfo,jvirt_sarray_ptr ptr,JDIMENSION start_row,JDIMENSION num_rows,boolean writable)809 access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
810 JDIMENSION start_row, JDIMENSION num_rows,
811 boolean writable)
812 /* Access the part of a virtual sample array starting at start_row */
813 /* and extending for num_rows rows. writable is true if */
814 /* caller intends to modify the accessed area. */
815 {
816 JDIMENSION end_row = start_row + num_rows;
817 JDIMENSION undef_row;
818
819 /* debugging check */
820 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
821 ptr->mem_buffer == NULL)
822 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
823
824 /* Make the desired part of the virtual array accessible */
825 if (start_row < ptr->cur_start_row ||
826 end_row > ptr->cur_start_row+ptr->rows_in_mem) {
827 if (! ptr->b_s_open)
828 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
829 /* Flush old buffer contents if necessary */
830 if (ptr->dirty) {
831 do_sarray_io(cinfo, ptr, TRUE);
832 ptr->dirty = FALSE;
833 }
834 /* Decide what part of virtual array to access.
835 * Algorithm: if target address > current window, assume forward scan,
836 * load starting at target address. If target address < current window,
837 * assume backward scan, load so that target area is top of window.
838 * Note that when switching from forward write to forward read, will have
839 * start_row = 0, so the limiting case applies and we load from 0 anyway.
840 */
841 if (start_row > ptr->cur_start_row) {
842 ptr->cur_start_row = start_row;
843 } else {
844 /* use long arithmetic here to avoid overflow & unsigned problems */
845 long ltemp;
846
847 ltemp = (long) end_row - (long) ptr->rows_in_mem;
848 if (ltemp < 0)
849 ltemp = 0; /* don't fall off front end of file */
850 ptr->cur_start_row = (JDIMENSION) ltemp;
851 }
852 /* Read in the selected part of the array.
853 * During the initial write pass, we will do no actual read
854 * because the selected part is all undefined.
855 */
856 do_sarray_io(cinfo, ptr, FALSE);
857 }
858 /* Ensure the accessed part of the array is defined; prezero if needed.
859 * To improve locality of access, we only prezero the part of the array
860 * that the caller is about to access, not the entire in-memory array.
861 */
862 if (ptr->first_undef_row < end_row) {
863 if (ptr->first_undef_row < start_row) {
864 if (writable) /* writer skipped over a section of array */
865 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
866 undef_row = start_row; /* but reader is allowed to read ahead */
867 } else {
868 undef_row = ptr->first_undef_row;
869 }
870 if (writable)
871 ptr->first_undef_row = end_row;
872 if (ptr->pre_zero) {
873 size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
874 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
875 end_row -= ptr->cur_start_row;
876 while (undef_row < end_row) {
877 jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
878 undef_row++;
879 }
880 } else {
881 if (! writable) /* reader looking at undefined data */
882 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
883 }
884 }
885 /* Flag the buffer dirty if caller will write in it */
886 if (writable)
887 ptr->dirty = TRUE;
888 /* Return address of proper part of the buffer */
889 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
890 }
891
892
893 METHODDEF(JBLOCKARRAY)
access_virt_barray(j_common_ptr cinfo,jvirt_barray_ptr ptr,JDIMENSION start_row,JDIMENSION num_rows,boolean writable)894 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
895 JDIMENSION start_row, JDIMENSION num_rows,
896 boolean writable)
897 /* Access the part of a virtual block array starting at start_row */
898 /* and extending for num_rows rows. writable is true if */
899 /* caller intends to modify the accessed area. */
900 {
901 JDIMENSION end_row = start_row + num_rows;
902 JDIMENSION undef_row;
903
904 /* debugging check */
905 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
906 ptr->mem_buffer == NULL)
907 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
908
909 /* Make the desired part of the virtual array accessible */
910 if (start_row < ptr->cur_start_row ||
911 end_row > ptr->cur_start_row+ptr->rows_in_mem) {
912 if (! ptr->b_s_open)
913 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
914 /* Flush old buffer contents if necessary */
915 if (ptr->dirty) {
916 do_barray_io(cinfo, ptr, TRUE);
917 ptr->dirty = FALSE;
918 }
919 /* Decide what part of virtual array to access.
920 * Algorithm: if target address > current window, assume forward scan,
921 * load starting at target address. If target address < current window,
922 * assume backward scan, load so that target area is top of window.
923 * Note that when switching from forward write to forward read, will have
924 * start_row = 0, so the limiting case applies and we load from 0 anyway.
925 */
926 if (start_row > ptr->cur_start_row) {
927 ptr->cur_start_row = start_row;
928 } else {
929 /* use long arithmetic here to avoid overflow & unsigned problems */
930 long ltemp;
931
932 ltemp = (long) end_row - (long) ptr->rows_in_mem;
933 if (ltemp < 0)
934 ltemp = 0; /* don't fall off front end of file */
935 ptr->cur_start_row = (JDIMENSION) ltemp;
936 }
937 /* Read in the selected part of the array.
938 * During the initial write pass, we will do no actual read
939 * because the selected part is all undefined.
940 */
941 do_barray_io(cinfo, ptr, FALSE);
942 }
943 /* Ensure the accessed part of the array is defined; prezero if needed.
944 * To improve locality of access, we only prezero the part of the array
945 * that the caller is about to access, not the entire in-memory array.
946 */
947 if (ptr->first_undef_row < end_row) {
948 if (ptr->first_undef_row < start_row) {
949 if (writable) /* writer skipped over a section of array */
950 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
951 undef_row = start_row; /* but reader is allowed to read ahead */
952 } else {
953 undef_row = ptr->first_undef_row;
954 }
955 if (writable)
956 ptr->first_undef_row = end_row;
957 if (ptr->pre_zero) {
958 size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
959 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
960 end_row -= ptr->cur_start_row;
961 while (undef_row < end_row) {
962 jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
963 undef_row++;
964 }
965 } else {
966 if (! writable) /* reader looking at undefined data */
967 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
968 }
969 }
970 /* Flag the buffer dirty if caller will write in it */
971 if (writable)
972 ptr->dirty = TRUE;
973 /* Return address of proper part of the buffer */
974 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
975 }
976
977
978 /*
979 * Release all objects belonging to a specified pool.
980 */
981
982 METHODDEF(void)
free_pool(j_common_ptr cinfo,int pool_id)983 free_pool (j_common_ptr cinfo, int pool_id)
984 {
985 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
986 small_pool_ptr shdr_ptr;
987 large_pool_ptr lhdr_ptr;
988 size_t space_freed;
989
990 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
991 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
992
993 #ifdef MEM_STATS
994 if (cinfo->err->trace_level > 1)
995 print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
996 #endif
997
998 /* If freeing IMAGE pool, close any virtual arrays first */
999 if (pool_id == JPOOL_IMAGE) {
1000 jvirt_sarray_ptr sptr;
1001 jvirt_barray_ptr bptr;
1002
1003 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
1004 if (sptr->b_s_open) { /* there may be no backing store */
1005 sptr->b_s_open = FALSE; /* prevent recursive close if error */
1006 (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
1007 }
1008 }
1009 mem->virt_sarray_list = NULL;
1010 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
1011 if (bptr->b_s_open) { /* there may be no backing store */
1012 bptr->b_s_open = FALSE; /* prevent recursive close if error */
1013 (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
1014 }
1015 }
1016 mem->virt_barray_list = NULL;
1017 }
1018
1019 /* Release large objects */
1020 lhdr_ptr = mem->large_list[pool_id];
1021 mem->large_list[pool_id] = NULL;
1022
1023 while (lhdr_ptr != NULL) {
1024 large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
1025 space_freed = lhdr_ptr->hdr.bytes_used +
1026 lhdr_ptr->hdr.bytes_left +
1027 SIZEOF(large_pool_hdr);
1028 jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
1029 mem->total_space_allocated -= (long)space_freed;
1030 lhdr_ptr = next_lhdr_ptr;
1031 }
1032
1033 /* Release small objects */
1034 shdr_ptr = mem->small_list[pool_id];
1035 mem->small_list[pool_id] = NULL;
1036
1037 while (shdr_ptr != NULL) {
1038 small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
1039 space_freed = shdr_ptr->hdr.bytes_used +
1040 shdr_ptr->hdr.bytes_left +
1041 SIZEOF(small_pool_hdr);
1042 jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
1043 mem->total_space_allocated -= (long)space_freed;
1044 shdr_ptr = next_shdr_ptr;
1045 }
1046 }
1047
1048
1049 /*
1050 * Close up shop entirely.
1051 * Note that this cannot be called unless cinfo->mem is non-NULL.
1052 */
1053
1054 METHODDEF(void)
self_destruct(j_common_ptr cinfo)1055 self_destruct (j_common_ptr cinfo)
1056 {
1057 int pool;
1058
1059 /* Close all backing store, release all memory.
1060 * Releasing pools in reverse order might help avoid fragmentation
1061 * with some (brain-damaged) malloc libraries.
1062 */
1063 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1064 free_pool(cinfo, pool);
1065 }
1066
1067 /* Release the memory manager control block too. */
1068 jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
1069 cinfo->mem = NULL; /* ensures I will be called only once */
1070
1071 jpeg_mem_term(cinfo); /* system-dependent cleanup */
1072 }
1073
1074
1075 /*
1076 * Memory manager initialization.
1077 * When this is called, only the error manager pointer is valid in cinfo!
1078 */
1079
1080 GLOBAL(void)
jinit_memory_mgr(j_common_ptr cinfo)1081 jinit_memory_mgr (j_common_ptr cinfo)
1082 {
1083 my_mem_ptr mem;
1084 long max_to_use;
1085 int pool;
1086 size_t test_mac;
1087
1088 cinfo->mem = NULL; /* for safety if init fails */
1089
1090 /* Check for configuration errors.
1091 * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
1092 * doesn't reflect any real hardware alignment requirement.
1093 * The test is a little tricky: for X>0, X and X-1 have no one-bits
1094 * in common if and only if X is a power of 2, ie has only one one-bit.
1095 * Some compilers may give an "unreachable code" warning here; ignore it.
1096 */
1097 if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
1098 ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
1099 /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
1100 * a multiple of SIZEOF(ALIGN_TYPE).
1101 * Again, an "unreachable code" warning may be ignored here.
1102 * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
1103 */
1104 test_mac = (size_t) MAX_ALLOC_CHUNK;
1105 if ((long) test_mac != MAX_ALLOC_CHUNK ||
1106 (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
1107 ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
1108
1109 max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
1110
1111 /* Attempt to allocate memory manager's control block */
1112 mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
1113
1114 if (mem == NULL) {
1115 jpeg_mem_term(cinfo); /* system-dependent cleanup */
1116 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
1117 }
1118
1119 /* OK, fill in the method pointers */
1120 mem->pub.alloc_small = alloc_small;
1121 mem->pub.alloc_large = alloc_large;
1122 mem->pub.alloc_sarray = alloc_sarray;
1123 mem->pub.alloc_barray = alloc_barray;
1124 #ifdef NEED_DARRAY
1125 mem->pub.alloc_darray = alloc_darray;
1126 #endif
1127 mem->pub.request_virt_sarray = request_virt_sarray;
1128 mem->pub.request_virt_barray = request_virt_barray;
1129 mem->pub.realize_virt_arrays = realize_virt_arrays;
1130 mem->pub.access_virt_sarray = access_virt_sarray;
1131 mem->pub.access_virt_barray = access_virt_barray;
1132 mem->pub.free_pool = free_pool;
1133 mem->pub.self_destruct = self_destruct;
1134
1135 /* Make MAX_ALLOC_CHUNK accessible to other modules */
1136 mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
1137
1138 /* Initialize working state */
1139 mem->pub.max_memory_to_use = max_to_use;
1140
1141 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1142 mem->small_list[pool] = NULL;
1143 mem->large_list[pool] = NULL;
1144 }
1145 mem->virt_sarray_list = NULL;
1146 mem->virt_barray_list = NULL;
1147
1148 mem->total_space_allocated = SIZEOF(my_memory_mgr);
1149
1150 /* Declare ourselves open for business */
1151 cinfo->mem = & mem->pub;
1152
1153 /* Check for an environment variable JPEGMEM; if found, override the
1154 * default max_memory setting from jpeg_mem_init. Note that the
1155 * surrounding application may again override this value.
1156 * If your system doesn't support getenv(), define NO_GETENV to disable
1157 * this feature.
1158 */
1159 #ifndef NO_GETENV
1160 { char * memenv;
1161
1162 if ((memenv = getenv("JPEGMEM")) != NULL) {
1163 char ch = 'x';
1164
1165 if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
1166 if (ch == 'm' || ch == 'M')
1167 max_to_use *= 1000L;
1168 mem->pub.max_memory_to_use = max_to_use * 1000L;
1169 }
1170 }
1171 }
1172 #endif
1173
1174 }
1175