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