1 /* 2 * jmemmgr.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * It was modified by The libjpeg-turbo Project to include only code and 7 * information relevant to libjpeg-turbo. 8 * For conditions of distribution and use, see the accompanying README file. 9 * 10 * This file contains the JPEG system-independent memory management 11 * routines. This code is usable across a wide variety of machines; most 12 * of the system dependencies have been isolated in a separate file. 13 * The major functions provided here are: 14 * * pool-based allocation and freeing of memory; 15 * * policy decisions about how to divide available memory among the 16 * virtual arrays; 17 * * control logic for swapping virtual arrays between main memory and 18 * backing storage. 19 * The separate system-dependent file provides the actual backing-storage 20 * access code, and it contains the policy decision about how much total 21 * main memory to use. 22 * This file is system-dependent in the sense that some of its functions 23 * are unnecessary in some systems. For example, if there is enough virtual 24 * memory so that backing storage will never be used, much of the virtual 25 * array control logic could be removed. (Of course, if you have that much 26 * memory then you shouldn't care about a little bit of unused code...) 27 */ 28 29 #define JPEG_INTERNALS 30 #define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */ 31 #include "jinclude.h" 32 #include "jpeglib.h" 33 #include "jmemsys.h" /* import the system-dependent declarations */ 34 35 #ifndef NO_GETENV 36 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare getenv() */ 37 extern char * getenv (const char * name); 38 #endif 39 #endif 40 41 42 LOCAL(size_t) 43 round_up_pow2 (size_t a, size_t b) 44 /* a rounded up to the next multiple of b, i.e. ceil(a/b)*b */ 45 /* Assumes a >= 0, b > 0, and b is a power of 2 */ 46 { 47 return ((a + b - 1) & (~(b - 1))); 48 } 49 50 51 /* 52 * Some important notes: 53 * The allocation routines provided here must never return NULL. 54 * They should exit to error_exit if unsuccessful. 55 * 56 * It's not a good idea to try to merge the sarray and barray routines, 57 * even though they are textually almost the same, because samples are 58 * usually stored as bytes while coefficients are shorts or ints. Thus, 59 * in machines where byte pointers have a different representation from 60 * word pointers, the resulting machine code could not be the same. 61 */ 62 63 64 /* 65 * Many machines require storage alignment: longs must start on 4-byte 66 * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc() 67 * always returns pointers that are multiples of the worst-case alignment 68 * requirement, and we had better do so too. 69 * There isn't any really portable way to determine the worst-case alignment 70 * requirement. This module assumes that the alignment requirement is 71 * multiples of ALIGN_SIZE. 72 * By default, we define ALIGN_SIZE as sizeof(double). This is necessary on some 73 * workstations (where doubles really do need 8-byte alignment) and will work 74 * fine on nearly everything. If your machine has lesser alignment needs, 75 * you can save a few bytes by making ALIGN_SIZE smaller. 76 * The only place I know of where this will NOT work is certain Macintosh 77 * 680x0 compilers that define double as a 10-byte IEEE extended float. 78 * Doing 10-byte alignment is counterproductive because longwords won't be 79 * aligned well. Put "#define ALIGN_SIZE 4" in jconfig.h if you have 80 * such a compiler. 81 */ 82 83 #ifndef ALIGN_SIZE /* so can override from jconfig.h */ 84 #ifndef WITH_SIMD 85 #define ALIGN_SIZE sizeof(double) 86 #else 87 #define ALIGN_SIZE 16 /* Most SIMD implementations require this */ 88 #endif 89 #endif 90 91 /* 92 * We allocate objects from "pools", where each pool is gotten with a single 93 * request to jpeg_get_small() or jpeg_get_large(). There is no per-object 94 * overhead within a pool, except for alignment padding. Each pool has a 95 * header with a link to the next pool of the same class. 96 * Small and large pool headers are identical. 97 */ 98 99 typedef struct small_pool_struct * small_pool_ptr; 100 101 typedef struct small_pool_struct { 102 small_pool_ptr next; /* next in list of pools */ 103 size_t bytes_used; /* how many bytes already used within pool */ 104 size_t bytes_left; /* bytes still available in this pool */ 105 } small_pool_hdr; 106 107 typedef struct large_pool_struct * large_pool_ptr; 108 109 typedef struct large_pool_struct { 110 large_pool_ptr next; /* next in list of pools */ 111 size_t bytes_used; /* how many bytes already used within pool */ 112 size_t bytes_left; /* bytes still available in this pool */ 113 } large_pool_hdr; 114 115 /* 116 * Here is the full definition of a memory manager object. 117 */ 118 119 typedef struct { 120 struct jpeg_memory_mgr pub; /* public fields */ 121 122 /* Each pool identifier (lifetime class) names a linked list of pools. */ 123 small_pool_ptr small_list[JPOOL_NUMPOOLS]; 124 large_pool_ptr large_list[JPOOL_NUMPOOLS]; 125 126 /* Since we only have one lifetime class of virtual arrays, only one 127 * linked list is necessary (for each datatype). Note that the virtual 128 * array control blocks being linked together are actually stored somewhere 129 * in the small-pool list. 130 */ 131 jvirt_sarray_ptr virt_sarray_list; 132 jvirt_barray_ptr virt_barray_list; 133 134 /* This counts total space obtained from jpeg_get_small/large */ 135 size_t total_space_allocated; 136 137 /* alloc_sarray and alloc_barray set this value for use by virtual 138 * array routines. 139 */ 140 JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */ 141 } my_memory_mgr; 142 143 typedef my_memory_mgr * my_mem_ptr; 144 145 146 /* 147 * The control blocks for virtual arrays. 148 * Note that these blocks are allocated in the "small" pool area. 149 * System-dependent info for the associated backing store (if any) is hidden 150 * inside the backing_store_info struct. 151 */ 152 153 struct jvirt_sarray_control { 154 JSAMPARRAY mem_buffer; /* => the in-memory buffer */ 155 JDIMENSION rows_in_array; /* total virtual array height */ 156 JDIMENSION samplesperrow; /* width of array (and of memory buffer) */ 157 JDIMENSION maxaccess; /* max rows accessed by access_virt_sarray */ 158 JDIMENSION rows_in_mem; /* height of memory buffer */ 159 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */ 160 JDIMENSION cur_start_row; /* first logical row # in the buffer */ 161 JDIMENSION first_undef_row; /* row # of first uninitialized row */ 162 boolean pre_zero; /* pre-zero mode requested? */ 163 boolean dirty; /* do current buffer contents need written? */ 164 boolean b_s_open; /* is backing-store data valid? */ 165 jvirt_sarray_ptr next; /* link to next virtual sarray control block */ 166 backing_store_info b_s_info; /* System-dependent control info */ 167 }; 168 169 struct jvirt_barray_control { 170 JBLOCKARRAY mem_buffer; /* => the in-memory buffer */ 171 JDIMENSION rows_in_array; /* total virtual array height */ 172 JDIMENSION blocksperrow; /* width of array (and of memory buffer) */ 173 JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */ 174 JDIMENSION rows_in_mem; /* height of memory buffer */ 175 JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */ 176 JDIMENSION cur_start_row; /* first logical row # in the buffer */ 177 JDIMENSION first_undef_row; /* row # of first uninitialized row */ 178 boolean pre_zero; /* pre-zero mode requested? */ 179 boolean dirty; /* do current buffer contents need written? */ 180 boolean b_s_open; /* is backing-store data valid? */ 181 jvirt_barray_ptr next; /* link to next virtual barray control block */ 182 backing_store_info b_s_info; /* System-dependent control info */ 183 }; 184 185 186 #ifdef MEM_STATS /* optional extra stuff for statistics */ 187 188 LOCAL(void) 189 print_mem_stats (j_common_ptr cinfo, int pool_id) 190 { 191 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 192 small_pool_ptr shdr_ptr; 193 large_pool_ptr lhdr_ptr; 194 195 /* Since this is only a debugging stub, we can cheat a little by using 196 * fprintf directly rather than going through the trace message code. 197 * This is helpful because message parm array can't handle longs. 198 */ 199 fprintf(stderr, "Freeing pool %d, total space = %ld\n", 200 pool_id, mem->total_space_allocated); 201 202 for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL; 203 lhdr_ptr = lhdr_ptr->next) { 204 fprintf(stderr, " Large chunk used %ld\n", 205 (long) lhdr_ptr->bytes_used); 206 } 207 208 for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL; 209 shdr_ptr = shdr_ptr->next) { 210 fprintf(stderr, " Small chunk used %ld free %ld\n", 211 (long) shdr_ptr->bytes_used, 212 (long) shdr_ptr->bytes_left); 213 } 214 } 215 216 #endif /* MEM_STATS */ 217 218 219 LOCAL(void) 220 out_of_memory (j_common_ptr cinfo, int which) 221 /* Report an out-of-memory error and stop execution */ 222 /* If we compiled MEM_STATS support, report alloc requests before dying */ 223 { 224 #ifdef MEM_STATS 225 cinfo->err->trace_level = 2; /* force self_destruct to report stats */ 226 #endif 227 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which); 228 } 229 230 231 /* 232 * Allocation of "small" objects. 233 * 234 * For these, we use pooled storage. When a new pool must be created, 235 * we try to get enough space for the current request plus a "slop" factor, 236 * where the slop will be the amount of leftover space in the new pool. 237 * The speed vs. space tradeoff is largely determined by the slop values. 238 * A different slop value is provided for each pool class (lifetime), 239 * and we also distinguish the first pool of a class from later ones. 240 * NOTE: the values given work fairly well on both 16- and 32-bit-int 241 * machines, but may be too small if longs are 64 bits or more. 242 * 243 * Since we do not know what alignment malloc() gives us, we have to 244 * allocate ALIGN_SIZE-1 extra space per pool to have room for alignment 245 * adjustment. 246 */ 247 248 static const size_t first_pool_slop[JPOOL_NUMPOOLS] = 249 { 250 1600, /* first PERMANENT pool */ 251 16000 /* first IMAGE pool */ 252 }; 253 254 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] = 255 { 256 0, /* additional PERMANENT pools */ 257 5000 /* additional IMAGE pools */ 258 }; 259 260 #define MIN_SLOP 50 /* greater than 0 to avoid futile looping */ 261 262 263 METHODDEF(void *) 264 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject) 265 /* Allocate a "small" object */ 266 { 267 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 268 small_pool_ptr hdr_ptr, prev_hdr_ptr; 269 char * data_ptr; 270 size_t min_request, slop; 271 272 /* 273 * Round up the requested size to a multiple of ALIGN_SIZE in order 274 * to assure alignment for the next object allocated in the same pool 275 * and so that algorithms can straddle outside the proper area up 276 * to the next alignment. 277 */ 278 sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE); 279 280 /* Check for unsatisfiable request (do now to ensure no overflow below) */ 281 if ((sizeof(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) > MAX_ALLOC_CHUNK) 282 out_of_memory(cinfo, 1); /* request exceeds malloc's ability */ 283 284 /* See if space is available in any existing pool */ 285 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS) 286 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */ 287 prev_hdr_ptr = NULL; 288 hdr_ptr = mem->small_list[pool_id]; 289 while (hdr_ptr != NULL) { 290 if (hdr_ptr->bytes_left >= sizeofobject) 291 break; /* found pool with enough space */ 292 prev_hdr_ptr = hdr_ptr; 293 hdr_ptr = hdr_ptr->next; 294 } 295 296 /* Time to make a new pool? */ 297 if (hdr_ptr == NULL) { 298 /* min_request is what we need now, slop is what will be leftover */ 299 min_request = sizeof(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1; 300 if (prev_hdr_ptr == NULL) /* first pool in class? */ 301 slop = first_pool_slop[pool_id]; 302 else 303 slop = extra_pool_slop[pool_id]; 304 /* Don't ask for more than MAX_ALLOC_CHUNK */ 305 if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request)) 306 slop = (size_t) (MAX_ALLOC_CHUNK-min_request); 307 /* Try to get space, if fail reduce slop and try again */ 308 for (;;) { 309 hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop); 310 if (hdr_ptr != NULL) 311 break; 312 slop /= 2; 313 if (slop < MIN_SLOP) /* give up when it gets real small */ 314 out_of_memory(cinfo, 2); /* jpeg_get_small failed */ 315 } 316 mem->total_space_allocated += min_request + slop; 317 /* Success, initialize the new pool header and add to end of list */ 318 hdr_ptr->next = NULL; 319 hdr_ptr->bytes_used = 0; 320 hdr_ptr->bytes_left = sizeofobject + slop; 321 if (prev_hdr_ptr == NULL) /* first pool in class? */ 322 mem->small_list[pool_id] = hdr_ptr; 323 else 324 prev_hdr_ptr->next = hdr_ptr; 325 } 326 327 /* OK, allocate the object from the current pool */ 328 data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */ 329 data_ptr += sizeof(small_pool_hdr); /* ...by skipping the header... */ 330 if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */ 331 data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE; 332 data_ptr += hdr_ptr->bytes_used; /* point to place for object */ 333 hdr_ptr->bytes_used += sizeofobject; 334 hdr_ptr->bytes_left -= sizeofobject; 335 336 return (void *) data_ptr; 337 } 338 339 340 /* 341 * Allocation of "large" objects. 342 * 343 * The external semantics of these are the same as "small" objects. However, 344 * the pool management heuristics are quite different. We assume that each 345 * request is large enough that it may as well be passed directly to 346 * jpeg_get_large; the pool management just links everything together 347 * so that we can free it all on demand. 348 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY 349 * structures. The routines that create these structures (see below) 350 * deliberately bunch rows together to ensure a large request size. 351 */ 352 353 METHODDEF(void *) 354 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject) 355 /* Allocate a "large" object */ 356 { 357 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 358 large_pool_ptr hdr_ptr; 359 char * data_ptr; 360 361 /* 362 * Round up the requested size to a multiple of ALIGN_SIZE so that 363 * algorithms can straddle outside the proper area up to the next 364 * alignment. 365 */ 366 sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE); 367 368 /* Check for unsatisfiable request (do now to ensure no overflow below) */ 369 if ((sizeof(large_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) > MAX_ALLOC_CHUNK) 370 out_of_memory(cinfo, 3); /* request exceeds malloc's ability */ 371 372 /* Always make a new pool */ 373 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS) 374 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */ 375 376 hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject + 377 sizeof(large_pool_hdr) + 378 ALIGN_SIZE - 1); 379 if (hdr_ptr == NULL) 380 out_of_memory(cinfo, 4); /* jpeg_get_large failed */ 381 mem->total_space_allocated += sizeofobject + sizeof(large_pool_hdr) + ALIGN_SIZE - 1; 382 383 /* Success, initialize the new pool header and add to list */ 384 hdr_ptr->next = mem->large_list[pool_id]; 385 /* We maintain space counts in each pool header for statistical purposes, 386 * even though they are not needed for allocation. 387 */ 388 hdr_ptr->bytes_used = sizeofobject; 389 hdr_ptr->bytes_left = 0; 390 mem->large_list[pool_id] = hdr_ptr; 391 392 data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */ 393 data_ptr += sizeof(small_pool_hdr); /* ...by skipping the header... */ 394 if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */ 395 data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE; 396 397 return (void *) data_ptr; 398 } 399 400 401 /* 402 * Creation of 2-D sample arrays. 403 * 404 * To minimize allocation overhead and to allow I/O of large contiguous 405 * blocks, we allocate the sample rows in groups of as many rows as possible 406 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request. 407 * NB: the virtual array control routines, later in this file, know about 408 * this chunking of rows. The rowsperchunk value is left in the mem manager 409 * object so that it can be saved away if this sarray is the workspace for 410 * a virtual array. 411 * 412 * Since we are often upsampling with a factor 2, we align the size (not 413 * the start) to 2 * ALIGN_SIZE so that the upsampling routines don't have 414 * to be as careful about size. 415 */ 416 417 METHODDEF(JSAMPARRAY) 418 alloc_sarray (j_common_ptr cinfo, int pool_id, 419 JDIMENSION samplesperrow, JDIMENSION numrows) 420 /* Allocate a 2-D sample array */ 421 { 422 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 423 JSAMPARRAY result; 424 JSAMPROW workspace; 425 JDIMENSION rowsperchunk, currow, i; 426 long ltemp; 427 428 /* Make sure each row is properly aligned */ 429 if ((ALIGN_SIZE % sizeof(JSAMPLE)) != 0) 430 out_of_memory(cinfo, 5); /* safety check */ 431 samplesperrow = (JDIMENSION)round_up_pow2(samplesperrow, (2 * ALIGN_SIZE) / sizeof(JSAMPLE)); 432 433 /* Calculate max # of rows allowed in one allocation chunk */ 434 ltemp = (MAX_ALLOC_CHUNK-sizeof(large_pool_hdr)) / 435 ((long) samplesperrow * sizeof(JSAMPLE)); 436 if (ltemp <= 0) 437 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 438 if (ltemp < (long) numrows) 439 rowsperchunk = (JDIMENSION) ltemp; 440 else 441 rowsperchunk = numrows; 442 mem->last_rowsperchunk = rowsperchunk; 443 444 /* Get space for row pointers (small object) */ 445 result = (JSAMPARRAY) alloc_small(cinfo, pool_id, 446 (size_t) (numrows * sizeof(JSAMPROW))); 447 448 /* Get the rows themselves (large objects) */ 449 currow = 0; 450 while (currow < numrows) { 451 rowsperchunk = MIN(rowsperchunk, numrows - currow); 452 workspace = (JSAMPROW) alloc_large(cinfo, pool_id, 453 (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow 454 * sizeof(JSAMPLE))); 455 for (i = rowsperchunk; i > 0; i--) { 456 result[currow++] = workspace; 457 workspace += samplesperrow; 458 } 459 } 460 461 return result; 462 } 463 464 465 /* 466 * Creation of 2-D coefficient-block arrays. 467 * This is essentially the same as the code for sample arrays, above. 468 */ 469 470 METHODDEF(JBLOCKARRAY) 471 alloc_barray (j_common_ptr cinfo, int pool_id, 472 JDIMENSION blocksperrow, JDIMENSION numrows) 473 /* Allocate a 2-D coefficient-block array */ 474 { 475 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 476 JBLOCKARRAY result; 477 JBLOCKROW workspace; 478 JDIMENSION rowsperchunk, currow, i; 479 long ltemp; 480 481 /* Make sure each row is properly aligned */ 482 if ((sizeof(JBLOCK) % ALIGN_SIZE) != 0) 483 out_of_memory(cinfo, 6); /* safety check */ 484 485 /* Calculate max # of rows allowed in one allocation chunk */ 486 ltemp = (MAX_ALLOC_CHUNK-sizeof(large_pool_hdr)) / 487 ((long) blocksperrow * sizeof(JBLOCK)); 488 if (ltemp <= 0) 489 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 490 if (ltemp < (long) numrows) 491 rowsperchunk = (JDIMENSION) ltemp; 492 else 493 rowsperchunk = numrows; 494 mem->last_rowsperchunk = rowsperchunk; 495 496 /* Get space for row pointers (small object) */ 497 result = (JBLOCKARRAY) alloc_small(cinfo, pool_id, 498 (size_t) (numrows * sizeof(JBLOCKROW))); 499 500 /* Get the rows themselves (large objects) */ 501 currow = 0; 502 while (currow < numrows) { 503 rowsperchunk = MIN(rowsperchunk, numrows - currow); 504 workspace = (JBLOCKROW) alloc_large(cinfo, pool_id, 505 (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow 506 * sizeof(JBLOCK))); 507 for (i = rowsperchunk; i > 0; i--) { 508 result[currow++] = workspace; 509 workspace += blocksperrow; 510 } 511 } 512 513 return result; 514 } 515 516 517 /* 518 * About virtual array management: 519 * 520 * The above "normal" array routines are only used to allocate strip buffers 521 * (as wide as the image, but just a few rows high). Full-image-sized buffers 522 * are handled as "virtual" arrays. The array is still accessed a strip at a 523 * time, but the memory manager must save the whole array for repeated 524 * accesses. The intended implementation is that there is a strip buffer in 525 * memory (as high as is possible given the desired memory limit), plus a 526 * backing file that holds the rest of the array. 527 * 528 * The request_virt_array routines are told the total size of the image and 529 * the maximum number of rows that will be accessed at once. The in-memory 530 * buffer must be at least as large as the maxaccess value. 531 * 532 * The request routines create control blocks but not the in-memory buffers. 533 * That is postponed until realize_virt_arrays is called. At that time the 534 * total amount of space needed is known (approximately, anyway), so free 535 * memory can be divided up fairly. 536 * 537 * The access_virt_array routines are responsible for making a specific strip 538 * area accessible (after reading or writing the backing file, if necessary). 539 * Note that the access routines are told whether the caller intends to modify 540 * the accessed strip; during a read-only pass this saves having to rewrite 541 * data to disk. The access routines are also responsible for pre-zeroing 542 * any newly accessed rows, if pre-zeroing was requested. 543 * 544 * In current usage, the access requests are usually for nonoverlapping 545 * strips; that is, successive access start_row numbers differ by exactly 546 * num_rows = maxaccess. This means we can get good performance with simple 547 * buffer dump/reload logic, by making the in-memory buffer be a multiple 548 * of the access height; then there will never be accesses across bufferload 549 * boundaries. The code will still work with overlapping access requests, 550 * but it doesn't handle bufferload overlaps very efficiently. 551 */ 552 553 554 METHODDEF(jvirt_sarray_ptr) 555 request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero, 556 JDIMENSION samplesperrow, JDIMENSION numrows, 557 JDIMENSION maxaccess) 558 /* Request a virtual 2-D sample array */ 559 { 560 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 561 jvirt_sarray_ptr result; 562 563 /* Only IMAGE-lifetime virtual arrays are currently supported */ 564 if (pool_id != JPOOL_IMAGE) 565 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */ 566 567 /* get control block */ 568 result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id, 569 sizeof(struct jvirt_sarray_control)); 570 571 result->mem_buffer = NULL; /* marks array not yet realized */ 572 result->rows_in_array = numrows; 573 result->samplesperrow = samplesperrow; 574 result->maxaccess = maxaccess; 575 result->pre_zero = pre_zero; 576 result->b_s_open = FALSE; /* no associated backing-store object */ 577 result->next = mem->virt_sarray_list; /* add to list of virtual arrays */ 578 mem->virt_sarray_list = result; 579 580 return result; 581 } 582 583 584 METHODDEF(jvirt_barray_ptr) 585 request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero, 586 JDIMENSION blocksperrow, JDIMENSION numrows, 587 JDIMENSION maxaccess) 588 /* Request a virtual 2-D coefficient-block array */ 589 { 590 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 591 jvirt_barray_ptr result; 592 593 /* Only IMAGE-lifetime virtual arrays are currently supported */ 594 if (pool_id != JPOOL_IMAGE) 595 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */ 596 597 /* get control block */ 598 result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id, 599 sizeof(struct jvirt_barray_control)); 600 601 result->mem_buffer = NULL; /* marks array not yet realized */ 602 result->rows_in_array = numrows; 603 result->blocksperrow = blocksperrow; 604 result->maxaccess = maxaccess; 605 result->pre_zero = pre_zero; 606 result->b_s_open = FALSE; /* no associated backing-store object */ 607 result->next = mem->virt_barray_list; /* add to list of virtual arrays */ 608 mem->virt_barray_list = result; 609 610 return result; 611 } 612 613 614 METHODDEF(void) 615 realize_virt_arrays (j_common_ptr cinfo) 616 /* Allocate the in-memory buffers for any unrealized virtual arrays */ 617 { 618 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 619 size_t space_per_minheight, maximum_space, avail_mem; 620 size_t minheights, max_minheights; 621 jvirt_sarray_ptr sptr; 622 jvirt_barray_ptr bptr; 623 624 /* Compute the minimum space needed (maxaccess rows in each buffer) 625 * and the maximum space needed (full image height in each buffer). 626 * These may be of use to the system-dependent jpeg_mem_available routine. 627 */ 628 space_per_minheight = 0; 629 maximum_space = 0; 630 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) { 631 if (sptr->mem_buffer == NULL) { /* if not realized yet */ 632 space_per_minheight += (long) sptr->maxaccess * 633 (long) sptr->samplesperrow * sizeof(JSAMPLE); 634 maximum_space += (long) sptr->rows_in_array * 635 (long) sptr->samplesperrow * sizeof(JSAMPLE); 636 } 637 } 638 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) { 639 if (bptr->mem_buffer == NULL) { /* if not realized yet */ 640 space_per_minheight += (long) bptr->maxaccess * 641 (long) bptr->blocksperrow * sizeof(JBLOCK); 642 maximum_space += (long) bptr->rows_in_array * 643 (long) bptr->blocksperrow * sizeof(JBLOCK); 644 } 645 } 646 647 if (space_per_minheight <= 0) 648 return; /* no unrealized arrays, no work */ 649 650 /* Determine amount of memory to actually use; this is system-dependent. */ 651 avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space, 652 mem->total_space_allocated); 653 654 /* If the maximum space needed is available, make all the buffers full 655 * height; otherwise parcel it out with the same number of minheights 656 * in each buffer. 657 */ 658 if (avail_mem >= maximum_space) 659 max_minheights = 1000000000L; 660 else { 661 max_minheights = avail_mem / space_per_minheight; 662 /* If there doesn't seem to be enough space, try to get the minimum 663 * anyway. This allows a "stub" implementation of jpeg_mem_available(). 664 */ 665 if (max_minheights <= 0) 666 max_minheights = 1; 667 } 668 669 /* Allocate the in-memory buffers and initialize backing store as needed. */ 670 671 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) { 672 if (sptr->mem_buffer == NULL) { /* if not realized yet */ 673 minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L; 674 if (minheights <= max_minheights) { 675 /* This buffer fits in memory */ 676 sptr->rows_in_mem = sptr->rows_in_array; 677 } else { 678 /* It doesn't fit in memory, create backing store. */ 679 sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess); 680 jpeg_open_backing_store(cinfo, & sptr->b_s_info, 681 (long) sptr->rows_in_array * 682 (long) sptr->samplesperrow * 683 (long) sizeof(JSAMPLE)); 684 sptr->b_s_open = TRUE; 685 } 686 sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE, 687 sptr->samplesperrow, sptr->rows_in_mem); 688 sptr->rowsperchunk = mem->last_rowsperchunk; 689 sptr->cur_start_row = 0; 690 sptr->first_undef_row = 0; 691 sptr->dirty = FALSE; 692 } 693 } 694 695 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) { 696 if (bptr->mem_buffer == NULL) { /* if not realized yet */ 697 minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L; 698 if (minheights <= max_minheights) { 699 /* This buffer fits in memory */ 700 bptr->rows_in_mem = bptr->rows_in_array; 701 } else { 702 /* It doesn't fit in memory, create backing store. */ 703 bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess); 704 jpeg_open_backing_store(cinfo, & bptr->b_s_info, 705 (long) bptr->rows_in_array * 706 (long) bptr->blocksperrow * 707 (long) sizeof(JBLOCK)); 708 bptr->b_s_open = TRUE; 709 } 710 bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE, 711 bptr->blocksperrow, bptr->rows_in_mem); 712 bptr->rowsperchunk = mem->last_rowsperchunk; 713 bptr->cur_start_row = 0; 714 bptr->first_undef_row = 0; 715 bptr->dirty = FALSE; 716 } 717 } 718 } 719 720 721 LOCAL(void) 722 do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing) 723 /* Do backing store read or write of a virtual sample array */ 724 { 725 long bytesperrow, file_offset, byte_count, rows, thisrow, i; 726 727 bytesperrow = (long) ptr->samplesperrow * sizeof(JSAMPLE); 728 file_offset = ptr->cur_start_row * bytesperrow; 729 /* Loop to read or write each allocation chunk in mem_buffer */ 730 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) { 731 /* One chunk, but check for short chunk at end of buffer */ 732 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i); 733 /* Transfer no more than is currently defined */ 734 thisrow = (long) ptr->cur_start_row + i; 735 rows = MIN(rows, (long) ptr->first_undef_row - thisrow); 736 /* Transfer no more than fits in file */ 737 rows = MIN(rows, (long) ptr->rows_in_array - thisrow); 738 if (rows <= 0) /* this chunk might be past end of file! */ 739 break; 740 byte_count = rows * bytesperrow; 741 if (writing) 742 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info, 743 (void *) ptr->mem_buffer[i], 744 file_offset, byte_count); 745 else 746 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info, 747 (void *) ptr->mem_buffer[i], 748 file_offset, byte_count); 749 file_offset += byte_count; 750 } 751 } 752 753 754 LOCAL(void) 755 do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing) 756 /* Do backing store read or write of a virtual coefficient-block array */ 757 { 758 long bytesperrow, file_offset, byte_count, rows, thisrow, i; 759 760 bytesperrow = (long) ptr->blocksperrow * sizeof(JBLOCK); 761 file_offset = ptr->cur_start_row * bytesperrow; 762 /* Loop to read or write each allocation chunk in mem_buffer */ 763 for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) { 764 /* One chunk, but check for short chunk at end of buffer */ 765 rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i); 766 /* Transfer no more than is currently defined */ 767 thisrow = (long) ptr->cur_start_row + i; 768 rows = MIN(rows, (long) ptr->first_undef_row - thisrow); 769 /* Transfer no more than fits in file */ 770 rows = MIN(rows, (long) ptr->rows_in_array - thisrow); 771 if (rows <= 0) /* this chunk might be past end of file! */ 772 break; 773 byte_count = rows * bytesperrow; 774 if (writing) 775 (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info, 776 (void *) ptr->mem_buffer[i], 777 file_offset, byte_count); 778 else 779 (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info, 780 (void *) ptr->mem_buffer[i], 781 file_offset, byte_count); 782 file_offset += byte_count; 783 } 784 } 785 786 787 METHODDEF(JSAMPARRAY) 788 access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr, 789 JDIMENSION start_row, JDIMENSION num_rows, 790 boolean writable) 791 /* Access the part of a virtual sample array starting at start_row */ 792 /* and extending for num_rows rows. writable is true if */ 793 /* caller intends to modify the accessed area. */ 794 { 795 JDIMENSION end_row = start_row + num_rows; 796 JDIMENSION undef_row; 797 798 /* debugging check */ 799 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess || 800 ptr->mem_buffer == NULL) 801 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 802 803 /* Make the desired part of the virtual array accessible */ 804 if (start_row < ptr->cur_start_row || 805 end_row > ptr->cur_start_row+ptr->rows_in_mem) { 806 if (! ptr->b_s_open) 807 ERREXIT(cinfo, JERR_VIRTUAL_BUG); 808 /* Flush old buffer contents if necessary */ 809 if (ptr->dirty) { 810 do_sarray_io(cinfo, ptr, TRUE); 811 ptr->dirty = FALSE; 812 } 813 /* Decide what part of virtual array to access. 814 * Algorithm: if target address > current window, assume forward scan, 815 * load starting at target address. If target address < current window, 816 * assume backward scan, load so that target area is top of window. 817 * Note that when switching from forward write to forward read, will have 818 * start_row = 0, so the limiting case applies and we load from 0 anyway. 819 */ 820 if (start_row > ptr->cur_start_row) { 821 ptr->cur_start_row = start_row; 822 } else { 823 /* use long arithmetic here to avoid overflow & unsigned problems */ 824 long ltemp; 825 826 ltemp = (long) end_row - (long) ptr->rows_in_mem; 827 if (ltemp < 0) 828 ltemp = 0; /* don't fall off front end of file */ 829 ptr->cur_start_row = (JDIMENSION) ltemp; 830 } 831 /* Read in the selected part of the array. 832 * During the initial write pass, we will do no actual read 833 * because the selected part is all undefined. 834 */ 835 do_sarray_io(cinfo, ptr, FALSE); 836 } 837 /* Ensure the accessed part of the array is defined; prezero if needed. 838 * To improve locality of access, we only prezero the part of the array 839 * that the caller is about to access, not the entire in-memory array. 840 */ 841 if (ptr->first_undef_row < end_row) { 842 if (ptr->first_undef_row < start_row) { 843 if (writable) /* writer skipped over a section of array */ 844 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 845 undef_row = start_row; /* but reader is allowed to read ahead */ 846 } else { 847 undef_row = ptr->first_undef_row; 848 } 849 if (writable) 850 ptr->first_undef_row = end_row; 851 if (ptr->pre_zero) { 852 size_t bytesperrow = (size_t) ptr->samplesperrow * sizeof(JSAMPLE); 853 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */ 854 end_row -= ptr->cur_start_row; 855 while (undef_row < end_row) { 856 jzero_far((void *) ptr->mem_buffer[undef_row], bytesperrow); 857 undef_row++; 858 } 859 } else { 860 if (! writable) /* reader looking at undefined data */ 861 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 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 METHODDEF(JBLOCKARRAY) 873 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr, 874 JDIMENSION start_row, JDIMENSION num_rows, 875 boolean writable) 876 /* Access the part of a virtual block array starting at start_row */ 877 /* and extending for num_rows rows. writable is true if */ 878 /* caller intends to modify the accessed area. */ 879 { 880 JDIMENSION end_row = start_row + num_rows; 881 JDIMENSION undef_row; 882 883 /* debugging check */ 884 if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess || 885 ptr->mem_buffer == NULL) 886 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 887 888 /* Make the desired part of the virtual array accessible */ 889 if (start_row < ptr->cur_start_row || 890 end_row > ptr->cur_start_row+ptr->rows_in_mem) { 891 if (! ptr->b_s_open) 892 ERREXIT(cinfo, JERR_VIRTUAL_BUG); 893 /* Flush old buffer contents if necessary */ 894 if (ptr->dirty) { 895 do_barray_io(cinfo, ptr, TRUE); 896 ptr->dirty = FALSE; 897 } 898 /* Decide what part of virtual array to access. 899 * Algorithm: if target address > current window, assume forward scan, 900 * load starting at target address. If target address < current window, 901 * assume backward scan, load so that target area is top of window. 902 * Note that when switching from forward write to forward read, will have 903 * start_row = 0, so the limiting case applies and we load from 0 anyway. 904 */ 905 if (start_row > ptr->cur_start_row) { 906 ptr->cur_start_row = start_row; 907 } else { 908 /* use long arithmetic here to avoid overflow & unsigned problems */ 909 long ltemp; 910 911 ltemp = (long) end_row - (long) ptr->rows_in_mem; 912 if (ltemp < 0) 913 ltemp = 0; /* don't fall off front end of file */ 914 ptr->cur_start_row = (JDIMENSION) ltemp; 915 } 916 /* Read in the selected part of the array. 917 * During the initial write pass, we will do no actual read 918 * because the selected part is all undefined. 919 */ 920 do_barray_io(cinfo, ptr, FALSE); 921 } 922 /* Ensure the accessed part of the array is defined; prezero if needed. 923 * To improve locality of access, we only prezero the part of the array 924 * that the caller is about to access, not the entire in-memory array. 925 */ 926 if (ptr->first_undef_row < end_row) { 927 if (ptr->first_undef_row < start_row) { 928 if (writable) /* writer skipped over a section of array */ 929 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 930 undef_row = start_row; /* but reader is allowed to read ahead */ 931 } else { 932 undef_row = ptr->first_undef_row; 933 } 934 if (writable) 935 ptr->first_undef_row = end_row; 936 if (ptr->pre_zero) { 937 size_t bytesperrow = (size_t) ptr->blocksperrow * sizeof(JBLOCK); 938 undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */ 939 end_row -= ptr->cur_start_row; 940 while (undef_row < end_row) { 941 jzero_far((void *) ptr->mem_buffer[undef_row], bytesperrow); 942 undef_row++; 943 } 944 } else { 945 if (! writable) /* reader looking at undefined data */ 946 ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS); 947 } 948 } 949 /* Flag the buffer dirty if caller will write in it */ 950 if (writable) 951 ptr->dirty = TRUE; 952 /* Return address of proper part of the buffer */ 953 return ptr->mem_buffer + (start_row - ptr->cur_start_row); 954 } 955 956 957 /* 958 * Release all objects belonging to a specified pool. 959 */ 960 961 METHODDEF(void) 962 free_pool (j_common_ptr cinfo, int pool_id) 963 { 964 my_mem_ptr mem = (my_mem_ptr) cinfo->mem; 965 small_pool_ptr shdr_ptr; 966 large_pool_ptr lhdr_ptr; 967 size_t space_freed; 968 969 if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS) 970 ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */ 971 972 #ifdef MEM_STATS 973 if (cinfo->err->trace_level > 1) 974 print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */ 975 #endif 976 977 /* If freeing IMAGE pool, close any virtual arrays first */ 978 if (pool_id == JPOOL_IMAGE) { 979 jvirt_sarray_ptr sptr; 980 jvirt_barray_ptr bptr; 981 982 for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) { 983 if (sptr->b_s_open) { /* there may be no backing store */ 984 sptr->b_s_open = FALSE; /* prevent recursive close if error */ 985 (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info); 986 } 987 } 988 mem->virt_sarray_list = NULL; 989 for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) { 990 if (bptr->b_s_open) { /* there may be no backing store */ 991 bptr->b_s_open = FALSE; /* prevent recursive close if error */ 992 (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info); 993 } 994 } 995 mem->virt_barray_list = NULL; 996 } 997 998 /* Release large objects */ 999 lhdr_ptr = mem->large_list[pool_id]; 1000 mem->large_list[pool_id] = NULL; 1001 1002 while (lhdr_ptr != NULL) { 1003 large_pool_ptr next_lhdr_ptr = lhdr_ptr->next; 1004 space_freed = lhdr_ptr->bytes_used + 1005 lhdr_ptr->bytes_left + 1006 sizeof(large_pool_hdr); 1007 jpeg_free_large(cinfo, (void *) lhdr_ptr, space_freed); 1008 mem->total_space_allocated -= space_freed; 1009 lhdr_ptr = next_lhdr_ptr; 1010 } 1011 1012 /* Release small objects */ 1013 shdr_ptr = mem->small_list[pool_id]; 1014 mem->small_list[pool_id] = NULL; 1015 1016 while (shdr_ptr != NULL) { 1017 small_pool_ptr next_shdr_ptr = shdr_ptr->next; 1018 space_freed = shdr_ptr->bytes_used + 1019 shdr_ptr->bytes_left + 1020 sizeof(small_pool_hdr); 1021 jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed); 1022 mem->total_space_allocated -= space_freed; 1023 shdr_ptr = next_shdr_ptr; 1024 } 1025 } 1026 1027 1028 /* 1029 * Close up shop entirely. 1030 * Note that this cannot be called unless cinfo->mem is non-NULL. 1031 */ 1032 1033 METHODDEF(void) 1034 self_destruct (j_common_ptr cinfo) 1035 { 1036 int pool; 1037 1038 /* Close all backing store, release all memory. 1039 * Releasing pools in reverse order might help avoid fragmentation 1040 * with some (brain-damaged) malloc libraries. 1041 */ 1042 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) { 1043 free_pool(cinfo, pool); 1044 } 1045 1046 /* Release the memory manager control block too. */ 1047 jpeg_free_small(cinfo, (void *) cinfo->mem, sizeof(my_memory_mgr)); 1048 cinfo->mem = NULL; /* ensures I will be called only once */ 1049 1050 jpeg_mem_term(cinfo); /* system-dependent cleanup */ 1051 } 1052 1053 1054 /* 1055 * Memory manager initialization. 1056 * When this is called, only the error manager pointer is valid in cinfo! 1057 */ 1058 1059 GLOBAL(void) 1060 jinit_memory_mgr (j_common_ptr cinfo) 1061 { 1062 my_mem_ptr mem; 1063 long max_to_use; 1064 int pool; 1065 size_t test_mac; 1066 1067 cinfo->mem = NULL; /* for safety if init fails */ 1068 1069 /* Check for configuration errors. 1070 * sizeof(ALIGN_TYPE) should be a power of 2; otherwise, it probably 1071 * doesn't reflect any real hardware alignment requirement. 1072 * The test is a little tricky: for X>0, X and X-1 have no one-bits 1073 * in common if and only if X is a power of 2, ie has only one one-bit. 1074 * Some compilers may give an "unreachable code" warning here; ignore it. 1075 */ 1076 if ((ALIGN_SIZE & (ALIGN_SIZE-1)) != 0) 1077 ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE); 1078 /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be 1079 * a multiple of ALIGN_SIZE. 1080 * Again, an "unreachable code" warning may be ignored here. 1081 * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK. 1082 */ 1083 test_mac = (size_t) MAX_ALLOC_CHUNK; 1084 if ((long) test_mac != MAX_ALLOC_CHUNK || 1085 (MAX_ALLOC_CHUNK % ALIGN_SIZE) != 0) 1086 ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK); 1087 1088 max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */ 1089 1090 /* Attempt to allocate memory manager's control block */ 1091 mem = (my_mem_ptr) jpeg_get_small(cinfo, sizeof(my_memory_mgr)); 1092 1093 if (mem == NULL) { 1094 jpeg_mem_term(cinfo); /* system-dependent cleanup */ 1095 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0); 1096 } 1097 1098 /* OK, fill in the method pointers */ 1099 mem->pub.alloc_small = alloc_small; 1100 mem->pub.alloc_large = alloc_large; 1101 mem->pub.alloc_sarray = alloc_sarray; 1102 mem->pub.alloc_barray = alloc_barray; 1103 mem->pub.request_virt_sarray = request_virt_sarray; 1104 mem->pub.request_virt_barray = request_virt_barray; 1105 mem->pub.realize_virt_arrays = realize_virt_arrays; 1106 mem->pub.access_virt_sarray = access_virt_sarray; 1107 mem->pub.access_virt_barray = access_virt_barray; 1108 mem->pub.free_pool = free_pool; 1109 mem->pub.self_destruct = self_destruct; 1110 1111 /* Make MAX_ALLOC_CHUNK accessible to other modules */ 1112 mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK; 1113 1114 /* Initialize working state */ 1115 mem->pub.max_memory_to_use = max_to_use; 1116 1117 for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) { 1118 mem->small_list[pool] = NULL; 1119 mem->large_list[pool] = NULL; 1120 } 1121 mem->virt_sarray_list = NULL; 1122 mem->virt_barray_list = NULL; 1123 1124 mem->total_space_allocated = sizeof(my_memory_mgr); 1125 1126 /* Declare ourselves open for business */ 1127 cinfo->mem = & mem->pub; 1128 1129 /* Check for an environment variable JPEGMEM; if found, override the 1130 * default max_memory setting from jpeg_mem_init. Note that the 1131 * surrounding application may again override this value. 1132 * If your system doesn't support getenv(), define NO_GETENV to disable 1133 * this feature. 1134 */ 1135 #ifndef NO_GETENV 1136 { char * memenv; 1137 1138 if ((memenv = getenv("JPEGMEM")) != NULL) { 1139 char ch = 'x'; 1140 1141 if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) { 1142 if (ch == 'm' || ch == 'M') 1143 max_to_use *= 1000L; 1144 mem->pub.max_memory_to_use = max_to_use * 1000L; 1145 } 1146 } 1147 } 1148 #endif 1149 1150 } 1151
