1/*
2 * jmemmgr.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2016, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains the JPEG system-independent memory management
12 * routines. This code is usable across a wide variety of machines; most
13 * of the system dependencies have been isolated in a separate file.
14 * The major functions provided here are:
15 * * pool-based allocation and freeing of memory;
16 * * policy decisions about how to divide available memory among the
17 * virtual arrays;
18 * * control logic for swapping virtual arrays between main memory and
19 * backing storage.
20 * The separate system-dependent file provides the actual backing-storage
21 * access code, and it contains the policy decision about how much total
22 * main memory to use.
23 * This file is system-dependent in the sense that some of its functions
24 * are unnecessary in some systems. For example, if there is enough virtual
25 * memory so that backing storage will never be used, much of the virtual
26 * array control logic could be removed. (Of course, if you have that much
27 * memory then you shouldn't care about a little bit of unused code...)
28 */
29
30#define JPEG_INTERNALS
31#define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */
32#include "jinclude.h"
33#include "jpeglib.h"
34#include "jmemsys.h" /* import the system-dependent declarations */
35
36#ifndef NO_GETENV
37#ifndef HAVE_STDLIB_H /* <stdlib.h> should declare getenv() */
38extern char *getenv (const char *name);
39#endif
40#endif
41
42
43LOCAL(size_t)
44round_up_pow2 (size_t a, size_t b)
45/* a rounded up to the next multiple of b, i.e. ceil(a/b)*b */
46/* Assumes a >= 0, b > 0, and b is a power of 2 */
47{
48 return ((a + b - 1) & (~(b - 1)));
49}
50
51
52/*
53 * Some important notes:
54 * The allocation routines provided here must never return NULL.
55 * They should exit to error_exit if unsuccessful.
56 *
57 * It's not a good idea to try to merge the sarray and barray routines,
58 * even though they are textually almost the same, because samples are
59 * usually stored as bytes while coefficients are shorts or ints. Thus,
60 * in machines where byte pointers have a different representation from
61 * word pointers, the resulting machine code could not be the same.
62 */
63
64
65/*
66 * Many machines require storage alignment: longs must start on 4-byte
67 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
68 * always returns pointers that are multiples of the worst-case alignment
69 * requirement, and we had better do so too.
70 * There isn't any really portable way to determine the worst-case alignment
71 * requirement. This module assumes that the alignment requirement is
72 * multiples of ALIGN_SIZE.
73 * By default, we define ALIGN_SIZE as sizeof(double). This is necessary on
74 * some workstations (where doubles really do need 8-byte alignment) and will
75 * work fine on nearly everything. If your machine has lesser alignment needs,
76 * you can save a few bytes by making ALIGN_SIZE smaller.
77 * The only place I know of where this will NOT work is certain Macintosh
78 * 680x0 compilers that define double as a 10-byte IEEE extended float.
79 * Doing 10-byte alignment is counterproductive because longwords won't be
80 * aligned well. Put "#define ALIGN_SIZE 4" in jconfig.h if you have
81 * such a compiler.
82 */
83
84#ifndef ALIGN_SIZE /* so can override from jconfig.h */
85#ifndef WITH_SIMD
86#define ALIGN_SIZE sizeof(double)
87#else
88#define ALIGN_SIZE 16 /* Most SIMD implementations require this */
89#endif
90#endif
91
92/*
93 * We allocate objects from "pools", where each pool is gotten with a single
94 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
95 * overhead within a pool, except for alignment padding. Each pool has a
96 * header with a link to the next pool of the same class.
97 * Small and large pool headers are identical.
98 */
99
100typedef struct small_pool_struct *small_pool_ptr;
101
102typedef struct small_pool_struct {
103 small_pool_ptr next; /* next in list of pools */
104 size_t bytes_used; /* how many bytes already used within pool */
105 size_t bytes_left; /* bytes still available in this pool */
106} small_pool_hdr;
107
108typedef struct large_pool_struct *large_pool_ptr;
109
110typedef struct large_pool_struct {
111 large_pool_ptr next; /* next in list of pools */
112 size_t bytes_used; /* how many bytes already used within pool */
113 size_t bytes_left; /* bytes still available in this pool */
114} large_pool_hdr;
115
116/*
117 * Here is the full definition of a memory manager object.
118 */
119
120typedef struct {
121 struct jpeg_memory_mgr pub; /* public fields */
122
123 /* Each pool identifier (lifetime class) names a linked list of pools. */
124 small_pool_ptr small_list[JPOOL_NUMPOOLS];
125 large_pool_ptr large_list[JPOOL_NUMPOOLS];
126
127 /* Since we only have one lifetime class of virtual arrays, only one
128 * linked list is necessary (for each datatype). Note that the virtual
129 * array control blocks being linked together are actually stored somewhere
130 * in the small-pool list.
131 */
132 jvirt_sarray_ptr virt_sarray_list;
133 jvirt_barray_ptr virt_barray_list;
134
135 /* This counts total space obtained from jpeg_get_small/large */
136 size_t total_space_allocated;
137
138 /* alloc_sarray and alloc_barray set this value for use by virtual
139 * array routines.
140 */
141 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
142} my_memory_mgr;
143
144typedef my_memory_mgr *my_mem_ptr;
145
146
147/*
148 * The control blocks for virtual arrays.
149 * Note that these blocks are allocated in the "small" pool area.
150 * System-dependent info for the associated backing store (if any) is hidden
151 * inside the backing_store_info struct.
152 */
153
154struct jvirt_sarray_control {
155 JSAMPARRAY mem_buffer; /* => the in-memory buffer */
156 JDIMENSION rows_in_array; /* total virtual array height */
157 JDIMENSION samplesperrow; /* width of array (and of memory buffer) */
158 JDIMENSION maxaccess; /* max rows accessed by access_virt_sarray */
159 JDIMENSION rows_in_mem; /* height of memory buffer */
160 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
161 JDIMENSION cur_start_row; /* first logical row # in the buffer */
162 JDIMENSION first_undef_row; /* row # of first uninitialized row */
163 boolean pre_zero; /* pre-zero mode requested? */
164 boolean dirty; /* do current buffer contents need written? */
165 boolean b_s_open; /* is backing-store data valid? */
166 jvirt_sarray_ptr next; /* link to next virtual sarray control block */
167 backing_store_info b_s_info; /* System-dependent control info */
168};
169
170struct jvirt_barray_control {
171 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
172 JDIMENSION rows_in_array; /* total virtual array height */
173 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
174 JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */
175 JDIMENSION rows_in_mem; /* height of memory buffer */
176 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
177 JDIMENSION cur_start_row; /* first logical row # in the buffer */
178 JDIMENSION first_undef_row; /* row # of first uninitialized row */
179 boolean pre_zero; /* pre-zero mode requested? */
180 boolean dirty; /* do current buffer contents need written? */
181 boolean b_s_open; /* is backing-store data valid? */
182 jvirt_barray_ptr next; /* link to next virtual barray control block */
183 backing_store_info b_s_info; /* System-dependent control info */
184};
185
186
187#ifdef MEM_STATS /* optional extra stuff for statistics */
188
189LOCAL(void)
190print_mem_stats (j_common_ptr cinfo, int pool_id)
191{
192 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
193 small_pool_ptr shdr_ptr;
194 large_pool_ptr lhdr_ptr;
195
196 /* Since this is only a debugging stub, we can cheat a little by using
197 * fprintf directly rather than going through the trace message code.
198 * This is helpful because message parm array can't handle longs.
199 */
200 fprintf(stderr, "Freeing pool %d, total space = %ld\n",
201 pool_id, mem->total_space_allocated);
202
203 for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
204 lhdr_ptr = lhdr_ptr->next) {
205 fprintf(stderr, " Large chunk used %ld\n",
206 (long) lhdr_ptr->bytes_used);
207 }
208
209 for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
210 shdr_ptr = shdr_ptr->next) {
211 fprintf(stderr, " Small chunk used %ld free %ld\n",
212 (long) shdr_ptr->bytes_used,
213 (long) shdr_ptr->bytes_left);
214 }
215}
216
217#endif /* MEM_STATS */
218
219
220LOCAL(void)
221out_of_memory (j_common_ptr cinfo, int which)
222/* Report an out-of-memory error and stop execution */
223/* If we compiled MEM_STATS support, report alloc requests before dying */
224{
225#ifdef MEM_STATS
226 cinfo->err->trace_level = 2; /* force self_destruct to report stats */
227#endif
228 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
229}
230
231
232/*
233 * Allocation of "small" objects.
234 *
235 * For these, we use pooled storage. When a new pool must be created,
236 * we try to get enough space for the current request plus a "slop" factor,
237 * where the slop will be the amount of leftover space in the new pool.
238 * The speed vs. space tradeoff is largely determined by the slop values.
239 * A different slop value is provided for each pool class (lifetime),
240 * and we also distinguish the first pool of a class from later ones.
241 * NOTE: the values given work fairly well on both 16- and 32-bit-int
242 * machines, but may be too small if longs are 64 bits or more.
243 *
244 * Since we do not know what alignment malloc() gives us, we have to
245 * allocate ALIGN_SIZE-1 extra space per pool to have room for alignment
246 * adjustment.
247 */
248
249static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
250{
251 1600, /* first PERMANENT pool */
252 16000 /* first IMAGE pool */
253};
254
255static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
256{
257 0, /* additional PERMANENT pools */
258 5000 /* additional IMAGE pools */
259};
260
261#define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
262
263
264METHODDEF(void *)
265alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
266/* Allocate a "small" object */
267{
268 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
269 small_pool_ptr hdr_ptr, prev_hdr_ptr;
270 char *data_ptr;
271 size_t min_request, slop;
272
273 /*
274 * Round up the requested size to a multiple of ALIGN_SIZE in order
275 * to assure alignment for the next object allocated in the same pool
276 * and so that algorithms can straddle outside the proper area up
277 * to the next alignment.
278 */
279 if (sizeofobject > MAX_ALLOC_CHUNK) {
280 /* This prevents overflow/wrap-around in round_up_pow2() if sizeofobject
281 is close to SIZE_MAX. */
282 out_of_memory(cinfo, 7);
283 }
284 sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE);
285
286 /* Check for unsatisfiable request (do now to ensure no overflow below) */
287 if ((sizeof(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) >
288 MAX_ALLOC_CHUNK)
289 out_of_memory(cinfo, 1); /* request exceeds malloc's ability */
290
291 /* See if space is available in any existing pool */
292 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
293 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
294 prev_hdr_ptr = NULL;
295 hdr_ptr = mem->small_list[pool_id];
296 while (hdr_ptr != NULL) {
297 if (hdr_ptr->bytes_left >= sizeofobject)
298 break; /* found pool with enough space */
299 prev_hdr_ptr = hdr_ptr;
300 hdr_ptr = hdr_ptr->next;
301 }
302
303 /* Time to make a new pool? */
304 if (hdr_ptr == NULL) {
305 /* min_request is what we need now, slop is what will be leftover */
306 min_request = sizeof(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1;
307 if (prev_hdr_ptr == NULL) /* first pool in class? */
308 slop = first_pool_slop[pool_id];
309 else
310 slop = extra_pool_slop[pool_id];
311 /* Don't ask for more than MAX_ALLOC_CHUNK */
312 if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
313 slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
314 /* Try to get space, if fail reduce slop and try again */
315 for (;;) {
316 hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
317 if (hdr_ptr != NULL)
318 break;
319 slop /= 2;
320 if (slop < MIN_SLOP) /* give up when it gets real small */
321 out_of_memory(cinfo, 2); /* jpeg_get_small failed */
322 }
323 mem->total_space_allocated += min_request + slop;
324 /* Success, initialize the new pool header and add to end of list */
325 hdr_ptr->next = NULL;
326 hdr_ptr->bytes_used = 0;
327 hdr_ptr->bytes_left = sizeofobject + slop;
328 if (prev_hdr_ptr == NULL) /* first pool in class? */
329 mem->small_list[pool_id] = hdr_ptr;
330 else
331 prev_hdr_ptr->next = hdr_ptr;
332 }
333
334 /* OK, allocate the object from the current pool */
335 data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */
336 data_ptr += sizeof(small_pool_hdr); /* ...by skipping the header... */
337 if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */
338 data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE;
339 data_ptr += hdr_ptr->bytes_used; /* point to place for object */
340 hdr_ptr->bytes_used += sizeofobject;
341 hdr_ptr->bytes_left -= sizeofobject;
342
343 return (void *) data_ptr;
344}
345
346
347/*
348 * Allocation of "large" objects.
349 *
350 * The external semantics of these are the same as "small" objects. However,
351 * the pool management heuristics are quite different. We assume that each
352 * request is large enough that it may as well be passed directly to
353 * jpeg_get_large; the pool management just links everything together
354 * so that we can free it all on demand.
355 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
356 * structures. The routines that create these structures (see below)
357 * deliberately bunch rows together to ensure a large request size.
358 */
359
360METHODDEF(void *)
361alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
362/* Allocate a "large" object */
363{
364 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
365 large_pool_ptr hdr_ptr;
366 char *data_ptr;
367
368 /*
369 * Round up the requested size to a multiple of ALIGN_SIZE so that
370 * algorithms can straddle outside the proper area up to the next
371 * alignment.
372 */
373 if (sizeofobject > MAX_ALLOC_CHUNK) {
374 /* This prevents overflow/wrap-around in round_up_pow2() if sizeofobject
375 is close to SIZE_MAX. */
376 out_of_memory(cinfo, 8);
377 }
378 sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE);
379
380 /* Check for unsatisfiable request (do now to ensure no overflow below) */
381 if ((sizeof(large_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) >
382 MAX_ALLOC_CHUNK)
383 out_of_memory(cinfo, 3); /* request exceeds malloc's ability */
384
385 /* Always make a new pool */
386 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
387 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
388
389 hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
390 sizeof(large_pool_hdr) +
391 ALIGN_SIZE - 1);
392 if (hdr_ptr == NULL)
393 out_of_memory(cinfo, 4); /* jpeg_get_large failed */
394 mem->total_space_allocated += sizeofobject + sizeof(large_pool_hdr) +
395 ALIGN_SIZE - 1;
396
397 /* Success, initialize the new pool header and add to list */
398 hdr_ptr->next = mem->large_list[pool_id];
399 /* We maintain space counts in each pool header for statistical purposes,
400 * even though they are not needed for allocation.
401 */
402 hdr_ptr->bytes_used = sizeofobject;
403 hdr_ptr->bytes_left = 0;
404 mem->large_list[pool_id] = hdr_ptr;
405
406 data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */
407 data_ptr += sizeof(small_pool_hdr); /* ...by skipping the header... */
408 if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */
409 data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE;
410
411 return (void *) data_ptr;
412}
413
414
415/*
416 * Creation of 2-D sample arrays.
417 *
418 * To minimize allocation overhead and to allow I/O of large contiguous
419 * blocks, we allocate the sample rows in groups of as many rows as possible
420 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
421 * NB: the virtual array control routines, later in this file, know about
422 * this chunking of rows. The rowsperchunk value is left in the mem manager
423 * object so that it can be saved away if this sarray is the workspace for
424 * a virtual array.
425 *
426 * Since we are often upsampling with a factor 2, we align the size (not
427 * the start) to 2 * ALIGN_SIZE so that the upsampling routines don't have
428 * to be as careful about size.
429 */
430
431METHODDEF(JSAMPARRAY)
432alloc_sarray (j_common_ptr cinfo, int pool_id,
433 JDIMENSION samplesperrow, JDIMENSION numrows)
434/* Allocate a 2-D sample array */
435{
436 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
437 JSAMPARRAY result;
438 JSAMPROW workspace;
439 JDIMENSION rowsperchunk, currow, i;
440 long ltemp;
441
442 /* Make sure each row is properly aligned */
443 if ((ALIGN_SIZE % sizeof(JSAMPLE)) != 0)
444 out_of_memory(cinfo, 5); /* safety check */
445
446 if (samplesperrow > MAX_ALLOC_CHUNK) {
447 /* This prevents overflow/wrap-around in round_up_pow2() if sizeofobject
448 is close to SIZE_MAX. */
449 out_of_memory(cinfo, 9);
450 }
451 samplesperrow = (JDIMENSION)round_up_pow2(samplesperrow, (2 * ALIGN_SIZE) /
452 sizeof(JSAMPLE));
453
454 /* Calculate max # of rows allowed in one allocation chunk */
455 ltemp = (MAX_ALLOC_CHUNK-sizeof(large_pool_hdr)) /
456 ((long) samplesperrow * sizeof(JSAMPLE));
457 if (ltemp <= 0)
458 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
459 if (ltemp < (long) 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 = (JSAMPARRAY) alloc_small(cinfo, pool_id,
467 (size_t) (numrows * sizeof(JSAMPROW)));
468
469 /* Get the rows themselves (large objects) */
470 currow = 0;
471 while (currow < numrows) {
472 rowsperchunk = MIN(rowsperchunk, numrows - currow);
473 workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
474 (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
475 * sizeof(JSAMPLE)));
476 for (i = rowsperchunk; i > 0; i--) {
477 result[currow++] = workspace;
478 workspace += samplesperrow;
479 }
480 }
481
482 return result;
483}
484
485
486/*
487 * Creation of 2-D coefficient-block arrays.
488 * This is essentially the same as the code for sample arrays, above.
489 */
490
491METHODDEF(JBLOCKARRAY)
492alloc_barray (j_common_ptr cinfo, int pool_id,
493 JDIMENSION blocksperrow, JDIMENSION numrows)
494/* Allocate a 2-D coefficient-block array */
495{
496 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
497 JBLOCKARRAY result;
498 JBLOCKROW workspace;
499 JDIMENSION rowsperchunk, currow, i;
500 long ltemp;
501
502 /* Make sure each row is properly aligned */
503 if ((sizeof(JBLOCK) % ALIGN_SIZE) != 0)
504 out_of_memory(cinfo, 6); /* safety check */
505
506 /* Calculate max # of rows allowed in one allocation chunk */
507 ltemp = (MAX_ALLOC_CHUNK-sizeof(large_pool_hdr)) /
508 ((long) blocksperrow * sizeof(JBLOCK));
509 if (ltemp <= 0)
510 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
511 if (ltemp < (long) numrows)
512 rowsperchunk = (JDIMENSION) ltemp;
513 else
514 rowsperchunk = numrows;
515 mem->last_rowsperchunk = rowsperchunk;
516
517 /* Get space for row pointers (small object) */
518 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
519 (size_t) (numrows * sizeof(JBLOCKROW)));
520
521 /* Get the rows themselves (large objects) */
522 currow = 0;
523 while (currow < numrows) {
524 rowsperchunk = MIN(rowsperchunk, numrows - currow);
525 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
526 (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
527 * sizeof(JBLOCK)));
528 for (i = rowsperchunk; i > 0; i--) {
529 result[currow++] = workspace;
530 workspace += blocksperrow;
531 }
532 }
533
534 return result;
535}
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
575METHODDEF(jvirt_sarray_ptr)
576request_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
605METHODDEF(jvirt_barray_ptr)
606request_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
635METHODDEF(void)
636realize_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 += (long) sptr->maxaccess *
654 (long) sptr->samplesperrow * sizeof(JSAMPLE);
655 maximum_space += (long) sptr->rows_in_array *
656 (long) 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 += (long) bptr->maxaccess *
662 (long) bptr->blocksperrow * sizeof(JBLOCK);
663 maximum_space += (long) bptr->rows_in_array *
664 (long) 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 = jpeg_mem_available(cinfo, space_per_minheight, 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 = ((long) 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 = ((long) 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
742LOCAL(void)
743do_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 long bytesperrow, file_offset, byte_count, rows, thisrow, i;
747
748 bytesperrow = (long) 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 < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
752 /* One chunk, but check for short chunk at end of buffer */
753 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
754 /* Transfer no more than is currently defined */
755 thisrow = (long) ptr->cur_start_row + i;
756 rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
757 /* Transfer no more than fits in file */
758 rows = MIN(rows, (long) 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 *) ptr->mem_buffer[i],
765 file_offset, byte_count);
766 else
767 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
768 (void *) ptr->mem_buffer[i],
769 file_offset, byte_count);
770 file_offset += byte_count;
771 }
772}
773
774
775LOCAL(void)
776do_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 long bytesperrow, file_offset, byte_count, rows, thisrow, i;
780
781 bytesperrow = (long) 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 < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
785 /* One chunk, but check for short chunk at end of buffer */
786 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
787 /* Transfer no more than is currently defined */
788 thisrow = (long) ptr->cur_start_row + i;
789 rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
790 /* Transfer no more than fits in file */
791 rows = MIN(rows, (long) 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 *) ptr->mem_buffer[i],
798 file_offset, byte_count);
799 else
800 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
801 (void *) ptr->mem_buffer[i],
802 file_offset, byte_count);
803 file_offset += byte_count;
804 }
805}
806
807
808METHODDEF(JSAMPARRAY)
809access_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 *) 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
893METHODDEF(JBLOCKARRAY)
894access_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 *) 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
982METHODDEF(void)
983free_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->next;
1025 space_freed = lhdr_ptr->bytes_used +
1026 lhdr_ptr->bytes_left +
1027 sizeof(large_pool_hdr);
1028 jpeg_free_large(cinfo, (void *) lhdr_ptr, space_freed);
1029 mem->total_space_allocated -= 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->next;
1039 space_freed = shdr_ptr->bytes_used +
1040 shdr_ptr->bytes_left +
1041 sizeof(small_pool_hdr);
1042 jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
1043 mem->total_space_allocated -= 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
1054METHODDEF(void)
1055self_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
1080GLOBAL(void)
1081jinit_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 ((ALIGN_SIZE & (ALIGN_SIZE-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 ALIGN_SIZE.
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 % ALIGN_SIZE) != 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 mem->pub.request_virt_sarray = request_virt_sarray;
1125 mem->pub.request_virt_barray = request_virt_barray;
1126 mem->pub.realize_virt_arrays = realize_virt_arrays;
1127 mem->pub.access_virt_sarray = access_virt_sarray;
1128 mem->pub.access_virt_barray = access_virt_barray;
1129 mem->pub.free_pool = free_pool;
1130 mem->pub.self_destruct = self_destruct;
1131
1132 /* Make MAX_ALLOC_CHUNK accessible to other modules */
1133 mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
1134
1135 /* Initialize working state */
1136 mem->pub.max_memory_to_use = max_to_use;
1137
1138 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1139 mem->small_list[pool] = NULL;
1140 mem->large_list[pool] = NULL;
1141 }
1142 mem->virt_sarray_list = NULL;
1143 mem->virt_barray_list = NULL;
1144
1145 mem->total_space_allocated = sizeof(my_memory_mgr);
1146
1147 /* Declare ourselves open for business */
1148 cinfo->mem = & mem->pub;
1149
1150 /* Check for an environment variable JPEGMEM; if found, override the
1151 * default max_memory setting from jpeg_mem_init. Note that the
1152 * surrounding application may again override this value.
1153 * If your system doesn't support getenv(), define NO_GETENV to disable
1154 * this feature.
1155 */
1156#ifndef NO_GETENV
1157 { char *memenv;
1158
1159 if ((memenv = getenv("JPEGMEM")) != NULL) {
1160 char ch = 'x';
1161
1162 if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
1163 if (ch == 'm' || ch == 'M')
1164 max_to_use *= 1000L;
1165 mem->pub.max_memory_to_use = max_to_use * 1000L;
1166 }
1167 }
1168 }
1169#endif
1170
1171}
1172