1 /*
2 * jmemmgr.c
3 *
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.
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 "jinclude.h"
30 #include "jpeglib.h"
31
32
33 /*
34 * Some important notes:
35 * The allocation routines provided here must never return NULL.
36 * They should exit to error_exit if unsuccessful.
37 *
38 * It's not a good idea to try to merge the sarray and barray routines,
39 * even though they are textually almost the same, because samples are
40 * usually stored as bytes while coefficients are shorts or ints. Thus,
41 * in machines where byte pointers have a different representation from
42 * word pointers, the resulting machine code could not be the same.
43 */
44
45
46 /*
47 * Many machines require storage alignment: longs must start on 4-byte
48 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
49 * always returns pointers that are multiples of the worst-case alignment
50 * requirement, and we had better do so too.
51 * There isn't any really portable way to determine the worst-case alignment
52 * requirement. This module assumes that the alignment requirement is
53 * multiples of sizeof(ALIGN_TYPE).
54 * By default, we define ALIGN_TYPE as double. This is necessary on some
55 * workstations (where doubles really do need 8-byte alignment) and will work
56 * fine on nearly everything. If your machine has lesser alignment needs,
57 * you can save a few bytes by making ALIGN_TYPE smaller.
58 * The only place I know of where this will NOT work is certain Macintosh
59 * 680x0 compilers that define double as a 10-byte IEEE extended float.
60 * Doing 10-byte alignment is counterproductive because longwords won't be
61 * aligned well. Put "#define ALIGN_TYPE long" in jconfig.h if you have
62 * such a compiler.
63 */
64
65 #ifndef ALIGN_TYPE /* so can override from jconfig.h */
66 #define ALIGN_TYPE double
67 #endif
68
69
70 /*
71 * We allocate objects from "pools", where each pool is gotten with a single
72 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
73 * overhead within a pool, except for alignment padding. Each pool has a
74 * header with a link to the next pool of the same class.
75 * Small and large pool headers are identical except that the latter's
76 * link pointer must be FAR on 80x86 machines.
77 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
78 * field. This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
79 * of the alignment requirement of ALIGN_TYPE.
80 */
81
82 typedef union small_pool_struct * small_pool_ptr;
83
84 typedef union small_pool_struct {
85 struct {
86 small_pool_ptr next; /* next in list of pools */
87 size_t bytes_used; /* how many bytes already used within pool */
88 size_t bytes_left; /* bytes still available in this pool */
89 } hdr;
90 ALIGN_TYPE dummy; /* included in union to ensure alignment */
91 } small_pool_hdr;
92
93 typedef union large_pool_struct * large_pool_ptr;
94
95 typedef union large_pool_struct {
96 struct {
97 large_pool_ptr next; /* next in list of pools */
98 size_t bytes_used; /* how many bytes already used within pool */
99 size_t bytes_left; /* bytes still available in this pool */
100 } hdr;
101 ALIGN_TYPE dummy; /* included in union to ensure alignment */
102 } large_pool_hdr;
103
104
105 /*
106 * Here is the full definition of a memory manager object.
107 */
108
109 typedef struct {
110 struct jpeg_memory_mgr pub; /* public fields */
111
112 /* Each pool identifier (lifetime class) names a linked list of pools. */
113 small_pool_ptr small_list[JPOOL_NUMPOOLS];
114 large_pool_ptr large_list[JPOOL_NUMPOOLS];
115
116 /* Since we only have one lifetime class of virtual arrays, only one
117 * linked list is necessary (for each datatype). Note that the virtual
118 * array control blocks being linked together are actually stored somewhere
119 * in the small-pool list.
120 */
121 jvirt_barray_ptr virt_barray_list;
122
123 /* alloc_sarray and alloc_barray set this value for use by virtual
124 * array routines.
125 */
126 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
127 } my_memory_mgr;
128
129 typedef my_memory_mgr * my_mem_ptr;
130
131
132 /*
133 * The control blocks for virtual arrays.
134 * Note that these blocks are allocated in the "small" pool area.
135 * System-dependent info for the associated backing store (if any) is hidden
136 * inside the backing_store_info struct.
137 */
138
139 struct jvirt_barray_control {
140 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
141 JDIMENSION rows_in_array; /* total virtual array height */
142 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
143 JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */
144 JDIMENSION rows_in_mem; /* height of memory buffer */
145 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
146 JDIMENSION cur_start_row; /* first logical row # in the buffer */
147 JDIMENSION first_undef_row; /* row # of first uninitialized row */
148 boolean pre_zero; /* pre-zero mode requested? */
149 boolean dirty; /* do current buffer contents need written? */
150 jvirt_barray_ptr next; /* link to next virtual barray control block */
151 };
152
153
154 LOCAL(void)
out_of_memory(j_common_ptr cinfo,int which)155 out_of_memory (j_common_ptr cinfo, int which)
156 /* Report an out-of-memory error and stop execution */
157 {
158 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
159 }
160
161
162 /*
163 * Allocation of "small" objects.
164 *
165 * For these, we use pooled storage. When a new pool must be created,
166 * we try to get enough space for the current request plus a "slop" factor,
167 * where the slop will be the amount of leftover space in the new pool.
168 * The speed vs. space tradeoff is largely determined by the slop values.
169 * A different slop value is provided for each pool class (lifetime),
170 * and we also distinguish the first pool of a class from later ones.
171 * NOTE: the values given work fairly well on both 16- and 32-bit-int
172 * machines, but may be too small if longs are 64 bits or more.
173 */
174
175 static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
176 {
177 1600, /* first PERMANENT pool */
178 16000 /* first IMAGE pool */
179 };
180
181 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
182 {
183 0, /* additional PERMANENT pools */
184 5000 /* additional IMAGE pools */
185 };
186
187 #define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
188
189
190 METHODDEF(void *)
alloc_small(j_common_ptr cinfo,int pool_id,size_t sizeofobject)191 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
192 /* Allocate a "small" object */
193 {
194 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
195 small_pool_ptr hdr_ptr, prev_hdr_ptr;
196 char * data_ptr;
197 size_t odd_bytes, min_request, slop;
198
199 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
200 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
201 if (odd_bytes > 0)
202 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
203
204 /* See if space is available in any existing pool */
205 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
206 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
207 prev_hdr_ptr = NULL;
208 hdr_ptr = mem->small_list[pool_id];
209 while (hdr_ptr != NULL) {
210 if (hdr_ptr->hdr.bytes_left >= sizeofobject)
211 break; /* found pool with enough space */
212 prev_hdr_ptr = hdr_ptr;
213 hdr_ptr = hdr_ptr->hdr.next;
214 }
215
216 /* Time to make a new pool? */
217 if (hdr_ptr == NULL) {
218 /* min_request is what we need now, slop is what will be leftover */
219 min_request = sizeofobject + SIZEOF(small_pool_hdr);
220 if (prev_hdr_ptr == NULL) /* first pool in class? */
221 slop = first_pool_slop[pool_id];
222 else
223 slop = extra_pool_slop[pool_id];
224 /* Try to get space, if fail reduce slop and try again */
225 for (;;) {
226 hdr_ptr = (small_pool_ptr) malloc(min_request + slop);
227 if (hdr_ptr != NULL)
228 break;
229 slop /= 2;
230 if (slop < MIN_SLOP) /* give up when it gets real small */
231 out_of_memory(cinfo, 2); /* jpeg_get_small failed */
232 }
233 /* Success, initialize the new pool header and add to end of list */
234 hdr_ptr->hdr.next = NULL;
235 hdr_ptr->hdr.bytes_used = 0;
236 hdr_ptr->hdr.bytes_left = sizeofobject + slop;
237 if (prev_hdr_ptr == NULL) /* first pool in class? */
238 mem->small_list[pool_id] = hdr_ptr;
239 else
240 prev_hdr_ptr->hdr.next = hdr_ptr;
241 }
242
243 /* OK, allocate the object from the current pool */
244 data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
245 data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
246 hdr_ptr->hdr.bytes_used += sizeofobject;
247 hdr_ptr->hdr.bytes_left -= sizeofobject;
248
249 return (void *) data_ptr;
250 }
251
252
253 /*
254 * Allocation of "large" objects.
255 *
256 * The external semantics of these are the same as "small" objects,
257 * except that FAR pointers are used on 80x86. However the pool
258 * management heuristics are quite different. We assume that each
259 * request is large enough that it may as well be passed directly to
260 * jpeg_get_large; the pool management just links everything together
261 * so that we can free it all on demand.
262 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
263 * structures. The routines that create these structures (see below)
264 * deliberately bunch rows together to ensure a large request size.
265 */
266
267 METHODDEF(void *)
alloc_large(j_common_ptr cinfo,int pool_id,size_t sizeofobject)268 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
269 /* Allocate a "large" object */
270 {
271 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
272 large_pool_ptr hdr_ptr;
273 size_t odd_bytes;
274
275 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
276 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
277 if (odd_bytes > 0)
278 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
279
280 /* Always make a new pool */
281 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
282 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
283
284 hdr_ptr = (large_pool_ptr) malloc(sizeofobject + SIZEOF(large_pool_hdr));
285 if (hdr_ptr == NULL)
286 out_of_memory(cinfo, 4); /* jpeg_get_large failed */
287
288 /* Success, initialize the new pool header and add to list */
289 hdr_ptr->hdr.next = mem->large_list[pool_id];
290 /* We maintain space counts in each pool header for statistical purposes,
291 * even though they are not needed for allocation.
292 */
293 hdr_ptr->hdr.bytes_used = sizeofobject;
294 hdr_ptr->hdr.bytes_left = 0;
295 mem->large_list[pool_id] = hdr_ptr;
296
297 return (void *) (hdr_ptr + 1); /* point to first data byte in pool */
298 }
299
300
301 /*
302 * Creation of 2-D sample arrays.
303 * The pointers are in near heap, the samples themselves in FAR heap.
304 *
305 * To minimize allocation overhead and to allow I/O of large contiguous
306 * blocks, we allocate the sample rows in groups of as many rows as possible
307 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
308 * NB: the virtual array control routines, later in this file, know about
309 * this chunking of rows. The rowsperchunk value is left in the mem manager
310 * object so that it can be saved away if this sarray is the workspace for
311 * a virtual array.
312 */
313
314 METHODDEF(JSAMPARRAY)
alloc_sarray(j_common_ptr cinfo,int pool_id,JDIMENSION samplesperrow,JDIMENSION numrows)315 alloc_sarray (j_common_ptr cinfo, int pool_id,
316 JDIMENSION samplesperrow, JDIMENSION numrows)
317 /* Allocate a 2-D sample array */
318 {
319 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
320 JSAMPARRAY result;
321 JSAMPROW workspace;
322 JDIMENSION i;
323
324 /* Calculate max # of rows allowed in one allocation chunk */
325 mem->last_rowsperchunk = numrows;
326
327 /* Get space for row pointers (small object) */
328 result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
329 (size_t) (numrows * SIZEOF(JSAMPROW)));
330
331 /* Get the rows themselves (large objects) */
332 workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
333 (size_t) ((size_t) numrows * (size_t) samplesperrow
334 * SIZEOF(JSAMPLE)));
335 for (i = 0; i < numrows; i++) {
336 result[i] = workspace;
337 workspace += samplesperrow;
338 }
339
340 return result;
341 }
342
343
344 /*
345 * Creation of 2-D coefficient-block arrays.
346 * This is essentially the same as the code for sample arrays, above.
347 */
348
349 METHODDEF(JBLOCKARRAY)
alloc_barray(j_common_ptr cinfo,int pool_id,JDIMENSION blocksperrow,JDIMENSION numrows)350 alloc_barray (j_common_ptr cinfo, int pool_id,
351 JDIMENSION blocksperrow, JDIMENSION numrows)
352 /* Allocate a 2-D coefficient-block array */
353 {
354 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
355 JBLOCKARRAY result;
356 JBLOCKROW workspace;
357 JDIMENSION i;
358
359 /* Calculate max # of rows allowed in one allocation chunk */
360 mem->last_rowsperchunk = numrows;
361
362 /* Get space for row pointers (small object) */
363 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
364 (size_t) (numrows * SIZEOF(JBLOCKROW)));
365
366 /* Get the rows themselves (large objects) */
367 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
368 (size_t) ((size_t) numrows * (size_t) blocksperrow
369 * SIZEOF(JBLOCK)));
370 for (i = 0; i < numrows; i++) {
371 result[i] = workspace;
372 workspace += blocksperrow;
373 }
374
375 return result;
376 }
377
378
379 /*
380 * About virtual array management:
381 *
382 * The above "normal" array routines are only used to allocate strip buffers
383 * (as wide as the image, but just a few rows high). Full-image-sized buffers
384 * are handled as "virtual" arrays. The array is still accessed a strip at a
385 * time, but the memory manager must save the whole array for repeated
386 * accesses. The intended implementation is that there is a strip buffer in
387 * memory (as high as is possible given the desired memory limit), plus a
388 * backing file that holds the rest of the array.
389 *
390 * The request_virt_array routines are told the total size of the image and
391 * the maximum number of rows that will be accessed at once. The in-memory
392 * buffer must be at least as large as the maxaccess value.
393 *
394 * The request routines create control blocks but not the in-memory buffers.
395 * That is postponed until realize_virt_arrays is called. At that time the
396 * total amount of space needed is known (approximately, anyway), so free
397 * memory can be divided up fairly.
398 *
399 * The access_virt_array routines are responsible for making a specific strip
400 * area accessible (after reading or writing the backing file, if necessary).
401 * Note that the access routines are told whether the caller intends to modify
402 * the accessed strip; during a read-only pass this saves having to rewrite
403 * data to disk. The access routines are also responsible for pre-zeroing
404 * any newly accessed rows, if pre-zeroing was requested.
405 *
406 * In current usage, the access requests are usually for nonoverlapping
407 * strips; that is, successive access start_row numbers differ by exactly
408 * num_rows = maxaccess. This means we can get good performance with simple
409 * buffer dump/reload logic, by making the in-memory buffer be a multiple
410 * of the access height; then there will never be accesses across bufferload
411 * boundaries. The code will still work with overlapping access requests,
412 * but it doesn't handle bufferload overlaps very efficiently.
413 */
414
415
416 METHODDEF(jvirt_barray_ptr)
request_virt_barray(j_common_ptr cinfo,int pool_id,boolean pre_zero,JDIMENSION blocksperrow,JDIMENSION numrows,JDIMENSION maxaccess)417 request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
418 JDIMENSION blocksperrow, JDIMENSION numrows,
419 JDIMENSION maxaccess)
420 /* Request a virtual 2-D coefficient-block array */
421 {
422 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
423 jvirt_barray_ptr result;
424
425 /* Only IMAGE-lifetime virtual arrays are currently supported */
426 if (pool_id != JPOOL_IMAGE)
427 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
428
429 /* get control block */
430 result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
431 SIZEOF(struct jvirt_barray_control));
432
433 result->mem_buffer = NULL; /* marks array not yet realized */
434 result->rows_in_array = numrows;
435 result->blocksperrow = blocksperrow;
436 result->maxaccess = maxaccess;
437 result->pre_zero = pre_zero;
438 result->next = mem->virt_barray_list; /* add to list of virtual arrays */
439 mem->virt_barray_list = result;
440
441 return result;
442 }
443
444
445 METHODDEF(void)
realize_virt_arrays(j_common_ptr cinfo)446 realize_virt_arrays (j_common_ptr cinfo)
447 /* Allocate the in-memory buffers for any unrealized virtual arrays */
448 {
449 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
450 long space_per_minheight;
451 long minheights;
452 jvirt_barray_ptr bptr;
453
454 /* Compute the minimum space needed (maxaccess rows in each buffer)
455 * and the maximum space needed (full image height in each buffer).
456 * These may be of use to the system-dependent jpeg_mem_available routine.
457 */
458 space_per_minheight = 0;
459 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
460 if (bptr->mem_buffer == NULL) { /* if not realized yet */
461 space_per_minheight += (long) bptr->maxaccess *
462 (long) bptr->blocksperrow * SIZEOF(JBLOCK);
463 }
464 }
465
466 if (space_per_minheight <= 0)
467 return; /* no unrealized arrays, no work */
468
469 /* Allocate the in-memory buffers and initialize backing store as needed. */
470
471 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
472 if (bptr->mem_buffer == NULL) { /* if not realized yet */
473 minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
474 bptr->rows_in_mem = bptr->rows_in_array;
475 bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
476 bptr->blocksperrow, bptr->rows_in_mem);
477 bptr->rowsperchunk = mem->last_rowsperchunk;
478 bptr->cur_start_row = 0;
479 bptr->first_undef_row = 0;
480 bptr->dirty = FALSE;
481 }
482 }
483 }
484
485
486
487 METHODDEF(JBLOCKARRAY)
access_virt_barray(j_common_ptr cinfo,jvirt_barray_ptr ptr,JDIMENSION start_row,JDIMENSION num_rows,boolean writable)488 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
489 JDIMENSION start_row, JDIMENSION num_rows,
490 boolean writable)
491 /* Access the part of a virtual block array starting at start_row */
492 /* and extending for num_rows rows. writable is true if */
493 /* caller intends to modify the accessed area. */
494 {
495 JDIMENSION end_row = start_row + num_rows;
496 JDIMENSION undef_row;
497
498 /* debugging check */
499 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
500 ptr->mem_buffer == NULL)
501 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
502
503 /* Make the desired part of the virtual array accessible */
504 if (start_row < ptr->cur_start_row || end_row > ptr->cur_start_row+ptr->rows_in_mem)
505 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
506
507 /* Ensure the accessed part of the array is defined; prezero if needed.
508 * To improve locality of access, we only prezero the part of the array
509 * that the caller is about to access, not the entire in-memory array.
510 */
511 if (ptr->first_undef_row < end_row) {
512 if (ptr->first_undef_row < start_row) {
513 if (writable) /* writer skipped over a section of array */
514 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
515 undef_row = start_row; /* but reader is allowed to read ahead */
516 } else {
517 undef_row = ptr->first_undef_row;
518 }
519 if (writable)
520 ptr->first_undef_row = end_row;
521 if (ptr->pre_zero) {
522 size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
523 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
524 end_row -= ptr->cur_start_row;
525 while (undef_row < end_row) {
526 MEMZERO((void *) ptr->mem_buffer[undef_row], bytesperrow);
527 undef_row++;
528 }
529 } else {
530 if (! writable) /* reader looking at undefined data */
531 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
532 }
533 }
534 /* Flag the buffer dirty if caller will write in it */
535 if (writable)
536 ptr->dirty = TRUE;
537 /* Return address of proper part of the buffer */
538 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
539 }
540
541
542 /*
543 * Release all objects belonging to a specified pool.
544 */
545
546 METHODDEF(void)
free_pool(j_common_ptr cinfo,int pool_id)547 free_pool (j_common_ptr cinfo, int pool_id)
548 {
549 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
550 small_pool_ptr shdr_ptr;
551 large_pool_ptr lhdr_ptr;
552
553 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
554 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
555
556 /* Release large objects */
557 lhdr_ptr = mem->large_list[pool_id];
558 mem->large_list[pool_id] = NULL;
559
560 while (lhdr_ptr != NULL) {
561 large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
562 free(lhdr_ptr);
563 lhdr_ptr = next_lhdr_ptr;
564 }
565
566 /* Release small objects */
567 shdr_ptr = mem->small_list[pool_id];
568 mem->small_list[pool_id] = NULL;
569
570 while (shdr_ptr != NULL) {
571 small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
572 free(shdr_ptr);
573 shdr_ptr = next_shdr_ptr;
574 }
575 }
576
577
578 /*
579 * Close up shop entirely.
580 * Note that this cannot be called unless cinfo->mem is non-NULL.
581 */
582
583 METHODDEF(void)
self_destruct(j_common_ptr cinfo)584 self_destruct (j_common_ptr cinfo)
585 {
586 int pool;
587
588 /* Close all backing store, release all memory.
589 * Releasing pools in reverse order might help avoid fragmentation
590 * with some (brain-damaged) malloc libraries.
591 */
592 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
593 free_pool(cinfo, pool);
594 }
595
596 /* Release the memory manager control block too. */
597 free(cinfo->mem);
598 cinfo->mem = NULL; /* ensures I will be called only once */
599 }
600
601
602 /*
603 * Memory manager initialization.
604 * When this is called, only the error manager pointer is valid in cinfo!
605 */
606
607 GLOBAL(void)
jinit_memory_mgr(j_common_ptr cinfo)608 jinit_memory_mgr (j_common_ptr cinfo)
609 {
610 my_mem_ptr mem;
611 int pool;
612
613 cinfo->mem = NULL; /* for safety if init fails */
614
615 /* Check for configuration errors.
616 * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
617 * doesn't reflect any real hardware alignment requirement.
618 * The test is a little tricky: for X>0, X and X-1 have no one-bits
619 * in common if and only if X is a power of 2, ie has only one one-bit.
620 * Some compilers may give an "unreachable code" warning here; ignore it.
621 */
622 if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
623 ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
624
625 /* Attempt to allocate memory manager's control block */
626 mem = (my_mem_ptr) malloc(SIZEOF(my_memory_mgr));
627
628 if (mem == NULL) {
629 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
630 }
631
632 /* OK, fill in the method pointers */
633 mem->pub.alloc_small = alloc_small;
634 mem->pub.alloc_large = alloc_large;
635 mem->pub.alloc_sarray = alloc_sarray;
636 mem->pub.alloc_barray = alloc_barray;
637 mem->pub.request_virt_barray = request_virt_barray;
638 mem->pub.realize_virt_arrays = realize_virt_arrays;
639 mem->pub.access_virt_barray = access_virt_barray;
640 mem->pub.free_pool = free_pool;
641 mem->pub.self_destruct = self_destruct;
642
643 /* Initialize working state */
644 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
645 mem->small_list[pool] = NULL;
646 mem->large_list[pool] = NULL;
647 }
648 mem->virt_barray_list = NULL;
649
650 /* Declare ourselves open for business */
651 cinfo->mem = & mem->pub;
652 }
653