1 /*
2 * jmemmgr.c
3 *
4 * Copyright (C) 1991-1994, 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 #include "jmemsys.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 and barray routines,
46 * even though they are textually almost the same, because samples are
47 * usually stored as bytes while coefficients are shorts or ints. Thus,
48 * in machines where byte pointers have a different representation from
49 * word pointers, the resulting machine code could not be the same.
50 */
51
52
53 /*
54 * Many machines require storage alignment: longs must start on 4-byte
55 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
56 * always returns pointers that are multiples of the worst-case alignment
57 * requirement, and we had better do so too.
58 * There isn't any really portable way to determine the worst-case alignment
59 * requirement. This module assumes that the alignment requirement is
60 * multiples of sizeof(ALIGN_TYPE).
61 * By default, we define ALIGN_TYPE as double. This is necessary on some
62 * workstations (where doubles really do need 8-byte alignment) and will work
63 * fine on nearly everything. If your machine has lesser alignment needs,
64 * you can save a few bytes by making ALIGN_TYPE smaller.
65 * The only place I know of where this will NOT work is certain Macintosh
66 * 680x0 compilers that define double as a 10-byte IEEE extended float.
67 * Doing 10-byte alignment is counterproductive because longwords won't be
68 * aligned well. Put "#define ALIGN_TYPE long" in jconfig.h if you have
69 * such a compiler.
70 */
71
72 #ifndef ALIGN_TYPE /* so can override from jconfig.h */
73 #define ALIGN_TYPE double
74 #endif
75
76
77 /*
78 * We allocate objects from "pools", where each pool is gotten with a single
79 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
80 * overhead within a pool, except for alignment padding. Each pool has a
81 * header with a link to the next pool of the same class.
82 * Small and large pool headers are identical except that the latter's
83 * link pointer must be FAR on 80x86 machines.
84 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
85 * field. This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
86 * of the alignment requirement of ALIGN_TYPE.
87 */
88
89 typedef union small_pool_struct * small_pool_ptr;
90
91 typedef union small_pool_struct {
92 struct {
93 small_pool_ptr next; /* next in list of pools */
94 size_t bytes_used; /* how many bytes already used within pool */
95 size_t bytes_left; /* bytes still available in this pool */
96 } hdr;
97 ALIGN_TYPE dummy; /* included in union to ensure alignment */
98 } small_pool_hdr;
99
100 typedef union large_pool_struct FAR * large_pool_ptr;
101
102 typedef union large_pool_struct {
103 struct {
104 large_pool_ptr next; /* next in list of pools */
105 size_t bytes_used; /* how many bytes already used within pool */
106 size_t bytes_left; /* bytes still available in this pool */
107 } hdr;
108 ALIGN_TYPE dummy; /* included in union to ensure alignment */
109 } large_pool_hdr;
110
111
112 /*
113 * Here is the full definition of a memory manager object.
114 */
115
116 typedef struct {
117 struct jpeg_memory_mgr pub; /* public fields */
118
119 /* Each pool identifier (lifetime class) names a linked list of pools. */
120 small_pool_ptr small_list[JPOOL_NUMPOOLS];
121 large_pool_ptr large_list[JPOOL_NUMPOOLS];
122
123 /* Since we only have one lifetime class of virtual arrays, only one
124 * linked list is necessary (for each datatype). Note that the virtual
125 * array control blocks being linked together are actually stored somewhere
126 * in the small-pool list.
127 */
128 jvirt_sarray_ptr virt_sarray_list;
129 jvirt_barray_ptr virt_barray_list;
130
131 /* This counts total space obtained from jpeg_get_small/large */
132 long total_space_allocated;
133
134 /* alloc_sarray and alloc_barray set this value for use by virtual
135 * array routines.
136 */
137 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
138 } my_memory_mgr;
139
140 typedef my_memory_mgr * my_mem_ptr;
141
142
143 /*
144 * The control blocks for virtual arrays.
145 * Note that these blocks are allocated in the "small" pool area.
146 * System-dependent info for the associated backing store (if any) is hidden
147 * inside the backing_store_info struct.
148 */
149
150 struct jvirt_sarray_control {
151 JSAMPARRAY mem_buffer; /* => the in-memory buffer */
152 JDIMENSION rows_in_array; /* total virtual array height */
153 JDIMENSION samplesperrow; /* width of array (and of memory buffer) */
154 JDIMENSION unitheight; /* # of rows accessed by access_virt_sarray */
155 JDIMENSION rows_in_mem; /* height of memory buffer */
156 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
157 JDIMENSION cur_start_row; /* first logical row # in the buffer */
158 boolean dirty; /* do current buffer contents need written? */
159 boolean b_s_open; /* is backing-store data valid? */
160 jvirt_sarray_ptr next; /* link to next virtual sarray control block */
161 backing_store_info b_s_info; /* System-dependent control info */
162 };
163
164 struct jvirt_barray_control {
165 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
166 JDIMENSION rows_in_array; /* total virtual array height */
167 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
168 JDIMENSION unitheight; /* # of rows accessed by access_virt_barray */
169 JDIMENSION rows_in_mem; /* height of memory buffer */
170 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
171 JDIMENSION cur_start_row; /* first logical row # in the buffer */
172 boolean dirty; /* do current buffer contents need written? */
173 boolean b_s_open; /* is backing-store data valid? */
174 jvirt_barray_ptr next; /* link to next virtual barray control block */
175 backing_store_info b_s_info; /* System-dependent control info */
176 };
177
178
179 #ifdef MEM_STATS /* optional extra stuff for statistics */
180
181 LOCAL void
print_mem_stats(j_common_ptr cinfo,int pool_id)182 print_mem_stats (j_common_ptr cinfo, int pool_id)
183 {
184 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
185 small_pool_ptr shdr_ptr;
186 large_pool_ptr lhdr_ptr;
187
188 /* Since this is only a debugging stub, we can cheat a little by using
189 * fprintf directly rather than going through the trace message code.
190 * This is helpful because message parm array can't handle longs.
191 */
192 fprintf(stderr, "Freeing pool %d, total space = %ld\n",
193 pool_id, mem->total_space_allocated);
194
195 for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
196 lhdr_ptr = lhdr_ptr->hdr.next) {
197 fprintf(stderr, " Large chunk used %ld\n",
198 (long) lhdr_ptr->hdr.bytes_used);
199 }
200
201 for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
202 shdr_ptr = shdr_ptr->hdr.next) {
203 fprintf(stderr, " Small chunk used %ld free %ld\n",
204 (long) shdr_ptr->hdr.bytes_used,
205 (long) shdr_ptr->hdr.bytes_left);
206 }
207 }
208
209 #endif /* MEM_STATS */
210
211
212 LOCAL void
out_of_memory(j_common_ptr cinfo,int which)213 out_of_memory (j_common_ptr cinfo, int which)
214 /* Report an out-of-memory error and stop execution */
215 /* If we compiled MEM_STATS support, report alloc requests before dying */
216 {
217 #ifdef MEM_STATS
218 cinfo->err->trace_level = 2; /* force self_destruct to report stats */
219 #endif
220 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
221 }
222
223
224 /*
225 * Allocation of "small" objects.
226 *
227 * For these, we use pooled storage. When a new pool must be created,
228 * we try to get enough space for the current request plus a "slop" factor,
229 * where the slop will be the amount of leftover space in the new pool.
230 * The speed vs. space tradeoff is largely determined by the slop values.
231 * A different slop value is provided for each pool class (lifetime),
232 * and we also distinguish the first pool of a class from later ones.
233 * NOTE: the values given work fairly well on both 16- and 32-bit-int
234 * machines, but may be too small if longs are 64 bits or more.
235 */
236
237 static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
238 {
239 1600, /* first PERMANENT pool */
240 16000 /* first IMAGE pool */
241 };
242
243 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
244 {
245 0, /* additional PERMANENT pools */
246 5000 /* additional IMAGE pools */
247 };
248
249 #define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
250
251
252 METHODDEF void *
alloc_small(j_common_ptr cinfo,int pool_id,size_t sizeofobject)253 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
254 /* Allocate a "small" object */
255 {
256 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
257 small_pool_ptr hdr_ptr, prev_hdr_ptr;
258 char * data_ptr;
259 size_t odd_bytes, min_request, slop;
260
261 /* Check for unsatisfiable request (do now to ensure no overflow below) */
262 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
263 out_of_memory(cinfo, 1); /* request exceeds malloc's ability */
264
265 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
266 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
267 if (odd_bytes > 0)
268 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
269
270 /* See if space is available in any existing pool */
271 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
272 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
273 prev_hdr_ptr = NULL;
274 hdr_ptr = mem->small_list[pool_id];
275 while (hdr_ptr != NULL) {
276 if (hdr_ptr->hdr.bytes_left >= sizeofobject)
277 break; /* found pool with enough space */
278 prev_hdr_ptr = hdr_ptr;
279 hdr_ptr = hdr_ptr->hdr.next;
280 }
281
282 /* Time to make a new pool? */
283 if (hdr_ptr == NULL) {
284 /* min_request is what we need now, slop is what will be leftover */
285 min_request = sizeofobject + SIZEOF(small_pool_hdr);
286 if (prev_hdr_ptr == NULL) /* first pool in class? */
287 slop = first_pool_slop[pool_id];
288 else
289 slop = extra_pool_slop[pool_id];
290 /* Don't ask for more than MAX_ALLOC_CHUNK */
291 if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
292 slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
293 /* Try to get space, if fail reduce slop and try again */
294 for (;;) {
295 hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
296 if (hdr_ptr != NULL)
297 break;
298 slop /= 2;
299 if (slop < MIN_SLOP) /* give up when it gets real small */
300 out_of_memory(cinfo, 2); /* jpeg_get_small failed */
301 }
302 mem->total_space_allocated += min_request + slop;
303 /* Success, initialize the new pool header and add to end of list */
304 hdr_ptr->hdr.next = NULL;
305 hdr_ptr->hdr.bytes_used = 0;
306 hdr_ptr->hdr.bytes_left = sizeofobject + slop;
307 if (prev_hdr_ptr == NULL) /* first pool in class? */
308 mem->small_list[pool_id] = hdr_ptr;
309 else
310 prev_hdr_ptr->hdr.next = hdr_ptr;
311 }
312
313 /* OK, allocate the object from the current pool */
314 data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
315 data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
316 hdr_ptr->hdr.bytes_used += sizeofobject;
317 hdr_ptr->hdr.bytes_left -= sizeofobject;
318
319 return (void *) data_ptr;
320 }
321
322
323 /*
324 * Allocation of "large" objects.
325 *
326 * The external semantics of these are the same as "small" objects,
327 * except that FAR pointers are used on 80x86. However the pool
328 * management heuristics are quite different. We assume that each
329 * request is large enough that it may as well be passed directly to
330 * jpeg_get_large; the pool management just links everything together
331 * so that we can free it all on demand.
332 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
333 * structures. The routines that create these structures (see below)
334 * deliberately bunch rows together to ensure a large request size.
335 */
336
337 METHODDEF void FAR *
alloc_large(j_common_ptr cinfo,int pool_id,size_t sizeofobject)338 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
339 /* Allocate a "large" object */
340 {
341 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
342 large_pool_ptr hdr_ptr;
343 size_t odd_bytes;
344
345 /* Check for unsatisfiable request (do now to ensure no overflow below) */
346 if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
347 out_of_memory(cinfo, 3); /* request exceeds malloc's ability */
348
349 /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
350 odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
351 if (odd_bytes > 0)
352 sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
353
354 /* Always make a new pool */
355 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
356 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
357
358 hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
359 SIZEOF(large_pool_hdr));
360 if (hdr_ptr == NULL)
361 out_of_memory(cinfo, 4); /* jpeg_get_large failed */
362 mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);
363
364 /* Success, initialize the new pool header and add to list */
365 hdr_ptr->hdr.next = mem->large_list[pool_id];
366 /* We maintain space counts in each pool header for statistical purposes,
367 * even though they are not needed for allocation.
368 */
369 hdr_ptr->hdr.bytes_used = sizeofobject;
370 hdr_ptr->hdr.bytes_left = 0;
371 mem->large_list[pool_id] = hdr_ptr;
372
373 return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
374 }
375
376
377 /*
378 * Creation of 2-D sample arrays.
379 * The pointers are in near heap, the samples themselves in FAR heap.
380 *
381 * To minimize allocation overhead and to allow I/O of large contiguous
382 * blocks, we allocate the sample rows in groups of as many rows as possible
383 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
384 * NB: the virtual array control routines, later in this file, know about
385 * this chunking of rows. The rowsperchunk value is left in the mem manager
386 * object so that it can be saved away if this sarray is the workspace for
387 * a virtual array.
388 */
389
390 METHODDEF JSAMPARRAY
alloc_sarray(j_common_ptr cinfo,int pool_id,JDIMENSION samplesperrow,JDIMENSION numrows)391 alloc_sarray (j_common_ptr cinfo, int pool_id,
392 JDIMENSION samplesperrow, JDIMENSION numrows)
393 /* Allocate a 2-D sample array */
394 {
395 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
396 JSAMPARRAY result;
397 JSAMPROW workspace;
398 JDIMENSION rowsperchunk, currow, i;
399 long ltemp;
400
401 /* Calculate max # of rows allowed in one allocation chunk */
402 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
403 ((long) samplesperrow * SIZEOF(JSAMPLE));
404 if (ltemp <= 0)
405 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
406 if (ltemp < (long) numrows)
407 rowsperchunk = (JDIMENSION) ltemp;
408 else
409 rowsperchunk = numrows;
410 mem->last_rowsperchunk = rowsperchunk;
411
412 /* Get space for row pointers (small object) */
413 result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
414 (size_t) (numrows * SIZEOF(JSAMPROW)));
415
416 /* Get the rows themselves (large objects) */
417 currow = 0;
418 while (currow < numrows) {
419 rowsperchunk = MIN(rowsperchunk, numrows - currow);
420 workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
421 (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
422 * SIZEOF(JSAMPLE)));
423 for (i = rowsperchunk; i > 0; i--) {
424 result[currow++] = workspace;
425 workspace += samplesperrow;
426 }
427 }
428
429 return result;
430 }
431
432
433 /*
434 * Creation of 2-D coefficient-block arrays.
435 * This is essentially the same as the code for sample arrays, above.
436 */
437
438 METHODDEF JBLOCKARRAY
alloc_barray(j_common_ptr cinfo,int pool_id,JDIMENSION blocksperrow,JDIMENSION numrows)439 alloc_barray (j_common_ptr cinfo, int pool_id,
440 JDIMENSION blocksperrow, JDIMENSION numrows)
441 /* Allocate a 2-D coefficient-block array */
442 {
443 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
444 JBLOCKARRAY result;
445 JBLOCKROW workspace;
446 JDIMENSION rowsperchunk, currow, i;
447 long ltemp;
448
449 /* Calculate max # of rows allowed in one allocation chunk */
450 ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
451 ((long) blocksperrow * SIZEOF(JBLOCK));
452 if (ltemp <= 0)
453 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
454 if (ltemp < (long) numrows)
455 rowsperchunk = (JDIMENSION) ltemp;
456 else
457 rowsperchunk = numrows;
458 mem->last_rowsperchunk = rowsperchunk;
459
460 /* Get space for row pointers (small object) */
461 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
462 (size_t) (numrows * SIZEOF(JBLOCKROW)));
463
464 /* Get the rows themselves (large objects) */
465 currow = 0;
466 while (currow < numrows) {
467 rowsperchunk = MIN(rowsperchunk, numrows - currow);
468 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
469 (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
470 * SIZEOF(JBLOCK)));
471 for (i = rowsperchunk; i > 0; i--) {
472 result[currow++] = workspace;
473 workspace += blocksperrow;
474 }
475 }
476
477 return result;
478 }
479
480
481 /*
482 * About virtual array management:
483 *
484 * To allow machines with limited memory to handle large images, all
485 * processing in the JPEG system is done a few pixel or block rows at a time.
486 * The above "normal" array routines are only used to allocate strip buffers
487 * (as wide as the image, but just a few rows high).
488 * In some cases multiple passes must be made over the data. In these
489 * cases the virtual array routines are used. The array is still accessed
490 * a strip at a time, but the memory manager must save the whole array
491 * for repeated accesses. The intended implementation is that there is
492 * a strip buffer in memory (as high as is possible given the desired memory
493 * limit), plus a backing file that holds the rest of the array.
494 *
495 * The request_virt_array routines are told the total size of the image and
496 * the unit height, which is the number of rows that will be accessed at once;
497 * the in-memory buffer should be made a multiple of this height for best
498 * efficiency.
499 *
500 * The request routines create control blocks but not the in-memory buffers.
501 * That is postponed until realize_virt_arrays is called. At that time the
502 * total amount of space needed is known (approximately, anyway), so free
503 * memory can be divided up fairly.
504 *
505 * The access_virt_array routines are responsible for making a specific strip
506 * area accessible (after reading or writing the backing file, if necessary).
507 * Note that the access routines are told whether the caller intends to modify
508 * the accessed strip; during a read-only pass this saves having to rewrite
509 * data to disk.
510 *
511 * The typical access pattern is one top-to-bottom pass to write the data,
512 * followed by one or more read-only top-to-bottom passes. However, other
513 * access patterns may occur while reading. For example, translation of image
514 * formats that use bottom-to-top scan order will require bottom-to-top read
515 * passes. The memory manager need not support multiple write passes nor
516 * funny write orders (meaning that rearranging rows must be handled while
517 * reading data out of the virtual array, not while putting it in). THIS WILL
518 * PROBABLY NEED TO CHANGE ... will need multiple write passes for progressive
519 * JPEG decoding.
520 *
521 * In current usage, the access requests are always for nonoverlapping strips;
522 * that is, successive access start_row numbers always differ by exactly the
523 * unitheight. This allows fairly simple buffer dump/reload logic if the
524 * in-memory buffer is made a multiple of the unitheight. The code below
525 * would work with overlapping access requests, but not very efficiently.
526 */
527
528
529 METHODDEF jvirt_sarray_ptr
request_virt_sarray(j_common_ptr cinfo,int pool_id,JDIMENSION samplesperrow,JDIMENSION numrows,JDIMENSION unitheight)530 request_virt_sarray (j_common_ptr cinfo, int pool_id,
531 JDIMENSION samplesperrow, JDIMENSION numrows,
532 JDIMENSION unitheight)
533 /* Request a virtual 2-D sample array */
534 {
535 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
536 jvirt_sarray_ptr result;
537
538 /* Only IMAGE-lifetime virtual arrays are currently supported */
539 if (pool_id != JPOOL_IMAGE)
540 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
541
542 /* Round array size up to a multiple of unitheight */
543 numrows = (JDIMENSION) jround_up((long) numrows, (long) unitheight);
544
545 /* get control block */
546 result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
547 SIZEOF(struct jvirt_sarray_control));
548
549 result->mem_buffer = NULL; /* marks array not yet realized */
550 result->rows_in_array = numrows;
551 result->samplesperrow = samplesperrow;
552 result->unitheight = unitheight;
553 result->b_s_open = FALSE; /* no associated backing-store object */
554 result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
555 mem->virt_sarray_list = result;
556
557 return result;
558 }
559
560
561 METHODDEF jvirt_barray_ptr
request_virt_barray(j_common_ptr cinfo,int pool_id,JDIMENSION blocksperrow,JDIMENSION numrows,JDIMENSION unitheight)562 request_virt_barray (j_common_ptr cinfo, int pool_id,
563 JDIMENSION blocksperrow, JDIMENSION numrows,
564 JDIMENSION unitheight)
565 /* Request a virtual 2-D coefficient-block array */
566 {
567 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
568 jvirt_barray_ptr result;
569
570 /* Only IMAGE-lifetime virtual arrays are currently supported */
571 if (pool_id != JPOOL_IMAGE)
572 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
573
574 /* Round array size up to a multiple of unitheight */
575 numrows = (JDIMENSION) jround_up((long) numrows, (long) unitheight);
576
577 /* get control block */
578 result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
579 SIZEOF(struct jvirt_barray_control));
580
581 result->mem_buffer = NULL; /* marks array not yet realized */
582 result->rows_in_array = numrows;
583 result->blocksperrow = blocksperrow;
584 result->unitheight = unitheight;
585 result->b_s_open = FALSE; /* no associated backing-store object */
586 result->next = mem->virt_barray_list; /* add to list of virtual arrays */
587 mem->virt_barray_list = result;
588
589 return result;
590 }
591
592
593 METHODDEF void
realize_virt_arrays(j_common_ptr cinfo)594 realize_virt_arrays (j_common_ptr cinfo)
595 /* Allocate the in-memory buffers for any unrealized virtual arrays */
596 {
597 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
598 long space_per_unitheight, maximum_space, avail_mem;
599 long unitheights, max_unitheights;
600 jvirt_sarray_ptr sptr;
601 jvirt_barray_ptr bptr;
602
603 /* Compute the minimum space needed (unitheight rows in each buffer)
604 * and the maximum space needed (full image height in each buffer).
605 * These may be of use to the system-dependent jpeg_mem_available routine.
606 */
607 space_per_unitheight = 0;
608 maximum_space = 0;
609 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
610 if (sptr->mem_buffer == NULL) { /* if not realized yet */
611 space_per_unitheight += (long) sptr->unitheight *
612 (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
613 maximum_space += (long) sptr->rows_in_array *
614 (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
615 }
616 }
617 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
618 if (bptr->mem_buffer == NULL) { /* if not realized yet */
619 space_per_unitheight += (long) bptr->unitheight *
620 (long) bptr->blocksperrow * SIZEOF(JBLOCK);
621 maximum_space += (long) bptr->rows_in_array *
622 (long) bptr->blocksperrow * SIZEOF(JBLOCK);
623 }
624 }
625
626 if (space_per_unitheight <= 0)
627 return; /* no unrealized arrays, no work */
628
629 /* Determine amount of memory to actually use; this is system-dependent. */
630 avail_mem = jpeg_mem_available(cinfo, space_per_unitheight, maximum_space,
631 mem->total_space_allocated);
632
633 /* If the maximum space needed is available, make all the buffers full
634 * height; otherwise parcel it out with the same number of unitheights
635 * in each buffer.
636 */
637 if (avail_mem >= maximum_space)
638 max_unitheights = 1000000000L;
639 else {
640 max_unitheights = avail_mem / space_per_unitheight;
641 /* If there doesn't seem to be enough space, try to get the minimum
642 * anyway. This allows a "stub" implementation of jpeg_mem_available().
643 */
644 if (max_unitheights <= 0)
645 max_unitheights = 1;
646 }
647
648 /* Allocate the in-memory buffers and initialize backing store as needed. */
649
650 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
651 if (sptr->mem_buffer == NULL) { /* if not realized yet */
652 unitheights = ((long) sptr->rows_in_array - 1L) / sptr->unitheight + 1L;
653 if (unitheights <= max_unitheights) {
654 /* This buffer fits in memory */
655 sptr->rows_in_mem = sptr->rows_in_array;
656 } else {
657 /* It doesn't fit in memory, create backing store. */
658 sptr->rows_in_mem = (JDIMENSION) (max_unitheights * sptr->unitheight);
659 jpeg_open_backing_store(cinfo, & sptr->b_s_info,
660 (long) sptr->rows_in_array *
661 (long) sptr->samplesperrow *
662 (long) SIZEOF(JSAMPLE));
663 sptr->b_s_open = TRUE;
664 }
665 sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
666 sptr->samplesperrow, sptr->rows_in_mem);
667 sptr->rowsperchunk = mem->last_rowsperchunk;
668 sptr->cur_start_row = 0;
669 sptr->dirty = FALSE;
670 }
671 }
672
673 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
674 if (bptr->mem_buffer == NULL) { /* if not realized yet */
675 unitheights = ((long) bptr->rows_in_array - 1L) / bptr->unitheight + 1L;
676 if (unitheights <= max_unitheights) {
677 /* This buffer fits in memory */
678 bptr->rows_in_mem = bptr->rows_in_array;
679 } else {
680 /* It doesn't fit in memory, create backing store. */
681 bptr->rows_in_mem = (JDIMENSION) (max_unitheights * bptr->unitheight);
682 jpeg_open_backing_store(cinfo, & bptr->b_s_info,
683 (long) bptr->rows_in_array *
684 (long) bptr->blocksperrow *
685 (long) SIZEOF(JBLOCK));
686 bptr->b_s_open = TRUE;
687 }
688 bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
689 bptr->blocksperrow, bptr->rows_in_mem);
690 bptr->rowsperchunk = mem->last_rowsperchunk;
691 bptr->cur_start_row = 0;
692 bptr->dirty = FALSE;
693 }
694 }
695 }
696
697
698 LOCAL void
do_sarray_io(j_common_ptr cinfo,jvirt_sarray_ptr ptr,boolean writing)699 do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
700 /* Do backing store read or write of a virtual sample array */
701 {
702 long bytesperrow, file_offset, byte_count, rows, i;
703
704 bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
705 file_offset = ptr->cur_start_row * bytesperrow;
706 /* Loop to read or write each allocation chunk in mem_buffer */
707 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
708 /* One chunk, but check for short chunk at end of buffer */
709 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
710 /* Transfer no more than fits in file */
711 rows = MIN(rows, (long) ptr->rows_in_array -
712 ((long) ptr->cur_start_row + i));
713 if (rows <= 0) /* this chunk might be past end of file! */
714 break;
715 byte_count = rows * bytesperrow;
716 if (writing)
717 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
718 (void FAR *) ptr->mem_buffer[i],
719 file_offset, byte_count);
720 else
721 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
722 (void FAR *) ptr->mem_buffer[i],
723 file_offset, byte_count);
724 file_offset += byte_count;
725 }
726 }
727
728
729 LOCAL void
do_barray_io(j_common_ptr cinfo,jvirt_barray_ptr ptr,boolean writing)730 do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
731 /* Do backing store read or write of a virtual coefficient-block array */
732 {
733 long bytesperrow, file_offset, byte_count, rows, i;
734
735 bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
736 file_offset = ptr->cur_start_row * bytesperrow;
737 /* Loop to read or write each allocation chunk in mem_buffer */
738 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
739 /* One chunk, but check for short chunk at end of buffer */
740 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
741 /* Transfer no more than fits in file */
742 rows = MIN(rows, (long) ptr->rows_in_array -
743 ((long) ptr->cur_start_row + i));
744 if (rows <= 0) /* this chunk might be past end of file! */
745 break;
746 byte_count = rows * bytesperrow;
747 if (writing)
748 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
749 (void FAR *) ptr->mem_buffer[i],
750 file_offset, byte_count);
751 else
752 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
753 (void FAR *) ptr->mem_buffer[i],
754 file_offset, byte_count);
755 file_offset += byte_count;
756 }
757 }
758
759
760 METHODDEF JSAMPARRAY
access_virt_sarray(j_common_ptr cinfo,jvirt_sarray_ptr ptr,JDIMENSION start_row,boolean writable)761 access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
762 JDIMENSION start_row, boolean writable)
763 /* Access the part of a virtual sample array starting at start_row */
764 /* and extending for ptr->unitheight rows. writable is true if */
765 /* caller intends to modify the accessed area. */
766 {
767 /* debugging check */
768 if (start_row >= ptr->rows_in_array || ptr->mem_buffer == NULL)
769 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
770
771 /* Make the desired part of the virtual array accessible */
772 if (start_row < ptr->cur_start_row ||
773 start_row+ptr->unitheight > ptr->cur_start_row+ptr->rows_in_mem) {
774 if (! ptr->b_s_open)
775 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
776 /* Flush old buffer contents if necessary */
777 if (ptr->dirty) {
778 do_sarray_io(cinfo, ptr, TRUE);
779 ptr->dirty = FALSE;
780 }
781 /* Decide what part of virtual array to access.
782 * Algorithm: if target address > current window, assume forward scan,
783 * load starting at target address. If target address < current window,
784 * assume backward scan, load so that target area is top of window.
785 * Note that when switching from forward write to forward read, will have
786 * start_row = 0, so the limiting case applies and we load from 0 anyway.
787 */
788 if (start_row > ptr->cur_start_row) {
789 ptr->cur_start_row = start_row;
790 } else {
791 /* use long arithmetic here to avoid overflow & unsigned problems */
792 long ltemp;
793
794 ltemp = (long) start_row + (long) ptr->unitheight -
795 (long) ptr->rows_in_mem;
796 if (ltemp < 0)
797 ltemp = 0; /* don't fall off front end of file */
798 ptr->cur_start_row = (JDIMENSION) ltemp;
799 }
800 /* If reading, read in the selected part of the array.
801 * If we are writing, we need not pre-read the selected portion,
802 * since the access sequence constraints ensure it would be garbage.
803 */
804 if (! writable) {
805 do_sarray_io(cinfo, ptr, FALSE);
806 }
807 }
808 /* Flag the buffer dirty if caller will write in it */
809 if (writable)
810 ptr->dirty = TRUE;
811 /* Return address of proper part of the buffer */
812 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
813 }
814
815
816 METHODDEF JBLOCKARRAY
access_virt_barray(j_common_ptr cinfo,jvirt_barray_ptr ptr,JDIMENSION start_row,boolean writable)817 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
818 JDIMENSION start_row, boolean writable)
819 /* Access the part of a virtual block array starting at start_row */
820 /* and extending for ptr->unitheight rows. writable is true if */
821 /* caller intends to modify the accessed area. */
822 {
823 /* debugging check */
824 if (start_row >= ptr->rows_in_array || ptr->mem_buffer == NULL)
825 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
826
827 /* Make the desired part of the virtual array accessible */
828 if (start_row < ptr->cur_start_row ||
829 start_row+ptr->unitheight > ptr->cur_start_row+ptr->rows_in_mem) {
830 if (! ptr->b_s_open)
831 ERREXIT(cinfo, JERR_VIRTUAL_BUG);
832 /* Flush old buffer contents if necessary */
833 if (ptr->dirty) {
834 do_barray_io(cinfo, ptr, TRUE);
835 ptr->dirty = FALSE;
836 }
837 /* Decide what part of virtual array to access.
838 * Algorithm: if target address > current window, assume forward scan,
839 * load starting at target address. If target address < current window,
840 * assume backward scan, load so that target area is top of window.
841 * Note that when switching from forward write to forward read, will have
842 * start_row = 0, so the limiting case applies and we load from 0 anyway.
843 */
844 if (start_row > ptr->cur_start_row) {
845 ptr->cur_start_row = start_row;
846 } else {
847 /* use long arithmetic here to avoid overflow & unsigned problems */
848 long ltemp;
849
850 ltemp = (long) start_row + (long) ptr->unitheight -
851 (long) ptr->rows_in_mem;
852 if (ltemp < 0)
853 ltemp = 0; /* don't fall off front end of file */
854 ptr->cur_start_row = (JDIMENSION) ltemp;
855 }
856 /* If reading, read in the selected part of the array.
857 * If we are writing, we need not pre-read the selected portion,
858 * since the access sequence constraints ensure it would be garbage.
859 */
860 if (! writable) {
861 do_barray_io(cinfo, ptr, FALSE);
862 }
863 }
864 /* Flag the buffer dirty if caller will write in it */
865 if (writable)
866 ptr->dirty = TRUE;
867 /* Return address of proper part of the buffer */
868 return ptr->mem_buffer + (start_row - ptr->cur_start_row);
869 }
870
871
872 /*
873 * Release all objects belonging to a specified pool.
874 */
875
876 METHODDEF void
free_pool(j_common_ptr cinfo,int pool_id)877 free_pool (j_common_ptr cinfo, int pool_id)
878 {
879 my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
880 small_pool_ptr shdr_ptr;
881 large_pool_ptr lhdr_ptr;
882 size_t space_freed;
883
884 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
885 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
886
887 #ifdef MEM_STATS
888 if (cinfo->err->trace_level > 1)
889 print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
890 #endif
891
892 /* If freeing IMAGE pool, close any virtual arrays first */
893 if (pool_id == JPOOL_IMAGE) {
894 jvirt_sarray_ptr sptr;
895 jvirt_barray_ptr bptr;
896
897 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
898 if (sptr->b_s_open) { /* there may be no backing store */
899 sptr->b_s_open = FALSE; /* prevent recursive close if error */
900 (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
901 }
902 }
903 mem->virt_sarray_list = NULL;
904 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
905 if (bptr->b_s_open) { /* there may be no backing store */
906 bptr->b_s_open = FALSE; /* prevent recursive close if error */
907 (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
908 }
909 }
910 mem->virt_barray_list = NULL;
911 }
912
913 /* Release large objects */
914 lhdr_ptr = mem->large_list[pool_id];
915 mem->large_list[pool_id] = NULL;
916
917 while (lhdr_ptr != NULL) {
918 large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
919 space_freed = lhdr_ptr->hdr.bytes_used +
920 lhdr_ptr->hdr.bytes_left +
921 SIZEOF(large_pool_hdr);
922 jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
923 mem->total_space_allocated -= space_freed;
924 lhdr_ptr = next_lhdr_ptr;
925 }
926
927 /* Release small objects */
928 shdr_ptr = mem->small_list[pool_id];
929 mem->small_list[pool_id] = NULL;
930
931 while (shdr_ptr != NULL) {
932 small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
933 space_freed = shdr_ptr->hdr.bytes_used +
934 shdr_ptr->hdr.bytes_left +
935 SIZEOF(small_pool_hdr);
936 jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
937 mem->total_space_allocated -= space_freed;
938 shdr_ptr = next_shdr_ptr;
939 }
940 }
941
942
943 /*
944 * Close up shop entirely.
945 * Note that this cannot be called unless cinfo->mem is non-NULL.
946 */
947
948 METHODDEF void
self_destruct(j_common_ptr cinfo)949 self_destruct (j_common_ptr cinfo)
950 {
951 int pool;
952
953 /* Close all backing store, release all memory.
954 * Releasing pools in reverse order might help avoid fragmentation
955 * with some (brain-damaged) malloc libraries.
956 */
957 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
958 free_pool(cinfo, pool);
959 }
960
961 /* Release the memory manager control block too. */
962 jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
963 cinfo->mem = NULL; /* ensures I will be called only once */
964
965 jpeg_mem_term(cinfo); /* system-dependent cleanup */
966 }
967
968
969 /*
970 * Memory manager initialization.
971 * When this is called, only the error manager pointer is valid in cinfo!
972 */
973
974 GLOBAL void
jinit_memory_mgr(j_common_ptr cinfo)975 jinit_memory_mgr (j_common_ptr cinfo)
976 {
977 my_mem_ptr mem;
978 long max_to_use;
979 int pool;
980 size_t test_mac;
981
982 cinfo->mem = NULL; /* for safety if init fails */
983
984 /* Check for configuration errors.
985 * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
986 * doesn't reflect any real hardware alignment requirement.
987 * The test is a little tricky: for X>0, X and X-1 have no one-bits
988 * in common if and only if X is a power of 2, ie has only one one-bit.
989 * Some compilers may give an "unreachable code" warning here; ignore it.
990 */
991 if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
992 ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
993 /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
994 * a multiple of SIZEOF(ALIGN_TYPE).
995 * Again, an "unreachable code" warning may be ignored here.
996 * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
997 */
998 test_mac = (size_t) MAX_ALLOC_CHUNK;
999 if ((long) test_mac != MAX_ALLOC_CHUNK ||
1000 (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
1001 ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
1002
1003 max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
1004
1005 /* Attempt to allocate memory manager's control block */
1006 mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
1007
1008 if (mem == NULL) {
1009 jpeg_mem_term(cinfo); /* system-dependent cleanup */
1010 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
1011 }
1012
1013 /* OK, fill in the method pointers */
1014 mem->pub.alloc_small = alloc_small;
1015 mem->pub.alloc_large = alloc_large;
1016 mem->pub.alloc_sarray = alloc_sarray;
1017 mem->pub.alloc_barray = alloc_barray;
1018 mem->pub.request_virt_sarray = request_virt_sarray;
1019 mem->pub.request_virt_barray = request_virt_barray;
1020 mem->pub.realize_virt_arrays = realize_virt_arrays;
1021 mem->pub.access_virt_sarray = access_virt_sarray;
1022 mem->pub.access_virt_barray = access_virt_barray;
1023 mem->pub.free_pool = free_pool;
1024 mem->pub.self_destruct = self_destruct;
1025
1026 /* Initialize working state */
1027 mem->pub.max_memory_to_use = max_to_use;
1028
1029 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1030 mem->small_list[pool] = NULL;
1031 mem->large_list[pool] = NULL;
1032 }
1033 mem->virt_sarray_list = NULL;
1034 mem->virt_barray_list = NULL;
1035
1036 mem->total_space_allocated = SIZEOF(my_memory_mgr);
1037
1038 /* Declare ourselves open for business */
1039 cinfo->mem = & mem->pub;
1040
1041 /* Check for an environment variable JPEGMEM; if found, override the
1042 * default max_memory setting from jpeg_mem_init. Note that the
1043 * surrounding application may again override this value.
1044 * If your system doesn't support getenv(), define NO_GETENV to disable
1045 * this feature.
1046 */
1047 #ifndef NO_GETENV
1048 { char * memenv;
1049
1050 if ((memenv = getenv("JPEGMEM")) != NULL) {
1051 char ch = 'x';
1052
1053 if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
1054 if (ch == 'm' || ch == 'M')
1055 max_to_use *= 1000L;
1056 mem->pub.max_memory_to_use = max_to_use * 1000L;
1057 }
1058 }
1059 }
1060 #endif
1061
1062 }
1063