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1
2 /* pngmem.c - stub functions for memory allocation
3 *
4 * Last changed in libpng 1.5.7 [December 15, 2011]
5 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8 *
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
12 *
13 * This file provides a location for all memory allocation. Users who
14 * need special memory handling are expected to supply replacement
15 * functions for png_malloc() and png_free(), and to use
16 * png_create_read_struct_2() and png_create_write_struct_2() to
17 * identify the replacement functions.
18 */
19
20 #include "pngpriv.h"
21
22 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
23
24 /* Borland DOS special memory handler */
25 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
26 /* If you change this, be sure to change the one in png.h also */
27
28 /* Allocate memory for a png_struct. The malloc and memset can be replaced
29 by a single call to calloc() if this is thought to improve performance. */
30 PNG_FUNCTION(png_voidp /* PRIVATE */,
31 png_create_struct,(int type),PNG_ALLOCATED)
32 {
33 # ifdef PNG_USER_MEM_SUPPORTED
34 return (png_create_struct_2(type, NULL, NULL));
35 }
36
37 /* Alternate version of png_create_struct, for use with user-defined malloc. */
38 PNG_FUNCTION(png_voidp /* PRIVATE */,
39 png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
40 PNG_ALLOCATED)
41 {
42 # endif /* PNG_USER_MEM_SUPPORTED */
43 png_size_t size;
44 png_voidp struct_ptr;
45
46 if (type == PNG_STRUCT_INFO)
47 size = png_sizeof(png_info);
48
49 else if (type == PNG_STRUCT_PNG)
50 size = png_sizeof(png_struct);
51
52 else
53 return (png_get_copyright(NULL));
54
55 # ifdef PNG_USER_MEM_SUPPORTED
56 if (malloc_fn != NULL)
57 {
58 png_struct dummy_struct;
59 memset(&dummy_struct, 0, sizeof dummy_struct);
60 dummy_struct.mem_ptr=mem_ptr;
61 struct_ptr = (*(malloc_fn))(&dummy_struct, (png_alloc_size_t)size);
62 }
63
64 else
65 # endif /* PNG_USER_MEM_SUPPORTED */
66 struct_ptr = (png_voidp)farmalloc(size);
67 if (struct_ptr != NULL)
68 png_memset(struct_ptr, 0, size);
69
70 return (struct_ptr);
71 }
72
73 /* Free memory allocated by a png_create_struct() call */
74 void /* PRIVATE */
75 png_destroy_struct(png_voidp struct_ptr)
76 {
77 # ifdef PNG_USER_MEM_SUPPORTED
78 png_destroy_struct_2(struct_ptr, NULL, NULL);
79 }
80
81 /* Free memory allocated by a png_create_struct() call */
82 void /* PRIVATE */
83 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
84 png_voidp mem_ptr)
85 {
86 # endif
87 if (struct_ptr != NULL)
88 {
89 # ifdef PNG_USER_MEM_SUPPORTED
90 if (free_fn != NULL)
91 {
92 png_struct dummy_struct;
93 memset(&dummy_struct, 0, sizeof dummy_struct);
94 dummy_struct.mem_ptr=mem_ptr;
95 (*(free_fn))(&dummy_struct, struct_ptr);
96 return;
97 }
98
99 # endif /* PNG_USER_MEM_SUPPORTED */
100 farfree (struct_ptr);
101 }
102 }
103
104 /* Allocate memory. For reasonable files, size should never exceed
105 * 64K. However, zlib may allocate more then 64K if you don't tell
106 * it not to. See zconf.h and png.h for more information. zlib does
107 * need to allocate exactly 64K, so whatever you call here must
108 * have the ability to do that.
109 *
110 * Borland seems to have a problem in DOS mode for exactly 64K.
111 * It gives you a segment with an offset of 8 (perhaps to store its
112 * memory stuff). zlib doesn't like this at all, so we have to
113 * detect and deal with it. This code should not be needed in
114 * Windows or OS/2 modes, and only in 16 bit mode. This code has
115 * been updated by Alexander Lehmann for version 0.89 to waste less
116 * memory.
117 *
118 * Note that we can't use png_size_t for the "size" declaration,
119 * since on some systems a png_size_t is a 16-bit quantity, and as a
120 * result, we would be truncating potentially larger memory requests
121 * (which should cause a fatal error) and introducing major problems.
122 */
123 PNG_FUNCTION(png_voidp,PNGAPI
124 png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
125 {
126 png_voidp ret;
127
128 ret = (png_malloc(png_ptr, size));
129
130 if (ret != NULL)
131 png_memset(ret,0,(png_size_t)size);
132
133 return (ret);
134 }
135
136 PNG_FUNCTION(png_voidp,PNGAPI
137 png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
138 {
139 png_voidp ret;
140
141 if (png_ptr == NULL || size == 0)
142 return (NULL);
143
144 # ifdef PNG_USER_MEM_SUPPORTED
145 if (png_ptr->malloc_fn != NULL)
146 ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
147
148 else
149 ret = (png_malloc_default(png_ptr, size));
150
151 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
152 png_error(png_ptr, "Out of memory");
153
154 return (ret);
155 }
156
157 PNG_FUNCTION(png_voidp,PNGAPI
158 png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
159 {
160 png_voidp ret;
161 # endif /* PNG_USER_MEM_SUPPORTED */
162
163 if (png_ptr == NULL || size == 0)
164 return (NULL);
165
166 # ifdef PNG_MAX_MALLOC_64K
167 if (size > (png_uint_32)65536L)
168 {
169 png_warning(png_ptr, "Cannot Allocate > 64K");
170 ret = NULL;
171 }
172
173 else
174 # endif
175
176 if (size != (size_t)size)
177 ret = NULL;
178
179 else if (size == (png_uint_32)65536L)
180 {
181 if (png_ptr->offset_table == NULL)
182 {
183 /* Try to see if we need to do any of this fancy stuff */
184 ret = farmalloc(size);
185 if (ret == NULL || ((png_size_t)ret & 0xffff))
186 {
187 int num_blocks;
188 png_uint_32 total_size;
189 png_bytep table;
190 int i, mem_level, window_bits;
191 png_byte huge * hptr;
192 int window_bits
193
194 if (ret != NULL)
195 {
196 farfree(ret);
197 ret = NULL;
198 }
199
200 window_bits =
201 png_ptr->zlib_window_bits >= png_ptr->zlib_text_window_bits ?
202 png_ptr->zlib_window_bits : png_ptr->zlib_text_window_bits;
203
204 if (window_bits > 14)
205 num_blocks = (int)(1 << (window_bits - 14));
206
207 else
208 num_blocks = 1;
209
210 mem_level =
211 png_ptr->zlib_mem_level >= png_ptr->zlib_text_mem_level ?
212 png_ptr->zlib_mem_level : png_ptr->zlib_text_mem_level;
213
214 if (mem_level >= 7)
215 num_blocks += (int)(1 << (mem_level - 7));
216
217 else
218 num_blocks++;
219
220 total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
221
222 table = farmalloc(total_size);
223
224 if (table == NULL)
225 {
226 # ifndef PNG_USER_MEM_SUPPORTED
227 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
228 png_error(png_ptr, "Out Of Memory"); /* Note "O", "M" */
229
230 else
231 png_warning(png_ptr, "Out Of Memory");
232 # endif
233 return (NULL);
234 }
235
236 if ((png_size_t)table & 0xfff0)
237 {
238 # ifndef PNG_USER_MEM_SUPPORTED
239 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
240 png_error(png_ptr,
241 "Farmalloc didn't return normalized pointer");
242
243 else
244 png_warning(png_ptr,
245 "Farmalloc didn't return normalized pointer");
246 # endif
247 return (NULL);
248 }
249
250 png_ptr->offset_table = table;
251 png_ptr->offset_table_ptr = farmalloc(num_blocks *
252 png_sizeof(png_bytep));
253
254 if (png_ptr->offset_table_ptr == NULL)
255 {
256 # ifndef PNG_USER_MEM_SUPPORTED
257 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
258 png_error(png_ptr, "Out Of memory"); /* Note "O", "m" */
259
260 else
261 png_warning(png_ptr, "Out Of memory");
262 # endif
263 return (NULL);
264 }
265
266 hptr = (png_byte huge *)table;
267 if ((png_size_t)hptr & 0xf)
268 {
269 hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
270 hptr = hptr + 16L; /* "hptr += 16L" fails on Turbo C++ 3.0 */
271 }
272
273 for (i = 0; i < num_blocks; i++)
274 {
275 png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
276 hptr = hptr + (png_uint_32)65536L; /* "+=" fails on TC++3.0 */
277 }
278
279 png_ptr->offset_table_number = num_blocks;
280 png_ptr->offset_table_count = 0;
281 png_ptr->offset_table_count_free = 0;
282 }
283 }
284
285 if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
286 {
287 # ifndef PNG_USER_MEM_SUPPORTED
288 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
289 png_error(png_ptr, "Out of Memory"); /* Note "O" and "M" */
290
291 else
292 png_warning(png_ptr, "Out of Memory");
293 # endif
294 return (NULL);
295 }
296
297 ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
298 }
299
300 else
301 ret = farmalloc(size);
302
303 # ifndef PNG_USER_MEM_SUPPORTED
304 if (ret == NULL)
305 {
306 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
307 png_error(png_ptr, "Out of memory"); /* Note "o" and "m" */
308
309 else
310 png_warning(png_ptr, "Out of memory"); /* Note "o" and "m" */
311 }
312 # endif
313
314 return (ret);
315 }
316
317 /* Free a pointer allocated by png_malloc(). In the default
318 * configuration, png_ptr is not used, but is passed in case it
319 * is needed. If ptr is NULL, return without taking any action.
320 */
321 void PNGAPI
322 png_free(png_structp png_ptr, png_voidp ptr)
323 {
324 if (png_ptr == NULL || ptr == NULL)
325 return;
326
327 # ifdef PNG_USER_MEM_SUPPORTED
328 if (png_ptr->free_fn != NULL)
329 {
330 (*(png_ptr->free_fn))(png_ptr, ptr);
331 return;
332 }
333
334 else
335 png_free_default(png_ptr, ptr);
336 }
337
338 void PNGAPI
339 png_free_default(png_structp png_ptr, png_voidp ptr)
340 {
341 # endif /* PNG_USER_MEM_SUPPORTED */
342
343 if (png_ptr == NULL || ptr == NULL)
344 return;
345
346 if (png_ptr->offset_table != NULL)
347 {
348 int i;
349
350 for (i = 0; i < png_ptr->offset_table_count; i++)
351 {
352 if (ptr == png_ptr->offset_table_ptr[i])
353 {
354 ptr = NULL;
355 png_ptr->offset_table_count_free++;
356 break;
357 }
358 }
359 if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
360 {
361 farfree(png_ptr->offset_table);
362 farfree(png_ptr->offset_table_ptr);
363 png_ptr->offset_table = NULL;
364 png_ptr->offset_table_ptr = NULL;
365 }
366 }
367
368 if (ptr != NULL)
369 farfree(ptr);
370 }
371
372 #else /* Not the Borland DOS special memory handler */
373
374 /* Allocate memory for a png_struct or a png_info. The malloc and
375 memset can be replaced by a single call to calloc() if this is thought
376 to improve performance noticably. */
377 PNG_FUNCTION(png_voidp /* PRIVATE */,
378 png_create_struct,(int type),PNG_ALLOCATED)
379 {
380 # ifdef PNG_USER_MEM_SUPPORTED
381 return (png_create_struct_2(type, NULL, NULL));
382 }
383
384 /* Allocate memory for a png_struct or a png_info. The malloc and
385 memset can be replaced by a single call to calloc() if this is thought
386 to improve performance noticably. */
387 PNG_FUNCTION(png_voidp /* PRIVATE */,
388 png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
389 PNG_ALLOCATED)
390 {
391 # endif /* PNG_USER_MEM_SUPPORTED */
392 png_size_t size;
393 png_voidp struct_ptr;
394
395 if (type == PNG_STRUCT_INFO)
396 size = png_sizeof(png_info);
397
398 else if (type == PNG_STRUCT_PNG)
399 size = png_sizeof(png_struct);
400
401 else
402 return (NULL);
403
404 # ifdef PNG_USER_MEM_SUPPORTED
405 if (malloc_fn != NULL)
406 {
407 png_struct dummy_struct;
408 png_structp png_ptr = &dummy_struct;
409 png_ptr->mem_ptr=mem_ptr;
410 struct_ptr = (*(malloc_fn))(png_ptr, size);
411
412 if (struct_ptr != NULL)
413 png_memset(struct_ptr, 0, size);
414
415 return (struct_ptr);
416 }
417 # endif /* PNG_USER_MEM_SUPPORTED */
418
419 # if defined(__TURBOC__) && !defined(__FLAT__)
420 struct_ptr = (png_voidp)farmalloc(size);
421 # else
422 # if defined(_MSC_VER) && defined(MAXSEG_64K)
423 struct_ptr = (png_voidp)halloc(size, 1);
424 # else
425 struct_ptr = (png_voidp)malloc(size);
426 # endif
427 # endif
428
429 if (struct_ptr != NULL)
430 png_memset(struct_ptr, 0, size);
431
432 return (struct_ptr);
433 }
434
435
436 /* Free memory allocated by a png_create_struct() call */
437 void /* PRIVATE */
438 png_destroy_struct(png_voidp struct_ptr)
439 {
440 # ifdef PNG_USER_MEM_SUPPORTED
441 png_destroy_struct_2(struct_ptr, NULL, NULL);
442 }
443
444 /* Free memory allocated by a png_create_struct() call */
445 void /* PRIVATE */
446 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
447 png_voidp mem_ptr)
448 {
449 # endif /* PNG_USER_MEM_SUPPORTED */
450 if (struct_ptr != NULL)
451 {
452 # ifdef PNG_USER_MEM_SUPPORTED
453 if (free_fn != NULL)
454 {
455 png_struct dummy_struct;
456 png_structp png_ptr = &dummy_struct;
457 png_ptr->mem_ptr=mem_ptr;
458 (*(free_fn))(png_ptr, struct_ptr);
459 return;
460 }
461 # endif /* PNG_USER_MEM_SUPPORTED */
462 # if defined(__TURBOC__) && !defined(__FLAT__)
463 farfree(struct_ptr);
464
465 # else
466 # if defined(_MSC_VER) && defined(MAXSEG_64K)
467 hfree(struct_ptr);
468
469 # else
470 free(struct_ptr);
471
472 # endif
473 # endif
474 }
475 }
476
477 /* Allocate memory. For reasonable files, size should never exceed
478 * 64K. However, zlib may allocate more then 64K if you don't tell
479 * it not to. See zconf.h and png.h for more information. zlib does
480 * need to allocate exactly 64K, so whatever you call here must
481 * have the ability to do that.
482 */
483
484 PNG_FUNCTION(png_voidp,PNGAPI
485 png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
486 {
487 png_voidp ret;
488
489 ret = (png_malloc(png_ptr, size));
490
491 if (ret != NULL)
492 png_memset(ret,0,(png_size_t)size);
493
494 return (ret);
495 }
496
497 PNG_FUNCTION(png_voidp,PNGAPI
498 png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
499 {
500 png_voidp ret;
501
502 # ifdef PNG_USER_MEM_SUPPORTED
503 if (png_ptr == NULL || size == 0)
504 return (NULL);
505
506 if (png_ptr->malloc_fn != NULL)
507 ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
508
509 else
510 ret = (png_malloc_default(png_ptr, size));
511
512 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
513 png_error(png_ptr, "Out of Memory");
514
515 return (ret);
516 }
517
518 PNG_FUNCTION(png_voidp,PNGAPI
519 png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
520 {
521 png_voidp ret;
522 # endif /* PNG_USER_MEM_SUPPORTED */
523
524 if (png_ptr == NULL || size == 0)
525 return (NULL);
526
527 # ifdef PNG_MAX_MALLOC_64K
528 if (size > (png_uint_32)65536L)
529 {
530 # ifndef PNG_USER_MEM_SUPPORTED
531 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
532 png_error(png_ptr, "Cannot Allocate > 64K");
533
534 else
535 # endif
536 return NULL;
537 }
538 # endif
539
540 /* Check for overflow */
541 # if defined(__TURBOC__) && !defined(__FLAT__)
542
543 if (size != (unsigned long)size)
544 ret = NULL;
545
546 else
547 ret = farmalloc(size);
548
549 # else
550 # if defined(_MSC_VER) && defined(MAXSEG_64K)
551 if (size != (unsigned long)size)
552 ret = NULL;
553
554 else
555 ret = halloc(size, 1);
556
557 # else
558 if (size != (size_t)size)
559 ret = NULL;
560
561 else
562 ret = malloc((size_t)size);
563 # endif
564 # endif
565
566 # ifndef PNG_USER_MEM_SUPPORTED
567 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
568 png_error(png_ptr, "Out of Memory");
569 # endif
570
571 return (ret);
572 }
573
574 /* Free a pointer allocated by png_malloc(). If ptr is NULL, return
575 * without taking any action.
576 */
577 void PNGAPI
578 png_free(png_structp png_ptr, png_voidp ptr)
579 {
580 if (png_ptr == NULL || ptr == NULL)
581 return;
582
583 # ifdef PNG_USER_MEM_SUPPORTED
584 if (png_ptr->free_fn != NULL)
585 {
586 (*(png_ptr->free_fn))(png_ptr, ptr);
587 return;
588 }
589
590 else
591 png_free_default(png_ptr, ptr);
592 }
593
594 void PNGAPI
595 png_free_default(png_structp png_ptr, png_voidp ptr)
596 {
597 if (png_ptr == NULL || ptr == NULL)
598 return;
599
600 # endif /* PNG_USER_MEM_SUPPORTED */
601
602 # if defined(__TURBOC__) && !defined(__FLAT__)
603 farfree(ptr);
604
605 # else
606 # if defined(_MSC_VER) && defined(MAXSEG_64K)
607 hfree(ptr);
608
609 # else
610 free(ptr);
611
612 # endif
613 # endif
614 }
615 #endif /* Not Borland DOS special memory handler */
616
617 /* This function was added at libpng version 1.2.3. The png_malloc_warn()
618 * function will set up png_malloc() to issue a png_warning and return NULL
619 * instead of issuing a png_error, if it fails to allocate the requested
620 * memory.
621 */
622 PNG_FUNCTION(png_voidp,PNGAPI
623 png_malloc_warn,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
624 {
625 png_voidp ptr;
626 png_uint_32 save_flags;
627 if (png_ptr == NULL)
628 return (NULL);
629
630 save_flags = png_ptr->flags;
631 png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
632 ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
633 png_ptr->flags=save_flags;
634 return(ptr);
635 }
636
637
638 #ifdef PNG_USER_MEM_SUPPORTED
639 /* This function is called when the application wants to use another method
640 * of allocating and freeing memory.
641 */
642 void PNGAPI
643 png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
644 malloc_fn, png_free_ptr free_fn)
645 {
646 if (png_ptr != NULL)
647 {
648 png_ptr->mem_ptr = mem_ptr;
649 png_ptr->malloc_fn = malloc_fn;
650 png_ptr->free_fn = free_fn;
651 }
652 }
653
654 /* This function returns a pointer to the mem_ptr associated with the user
655 * functions. The application should free any memory associated with this
656 * pointer before png_write_destroy and png_read_destroy are called.
657 */
658 png_voidp PNGAPI
659 png_get_mem_ptr(png_const_structp png_ptr)
660 {
661 if (png_ptr == NULL)
662 return (NULL);
663
664 return ((png_voidp)png_ptr->mem_ptr);
665 }
666 #endif /* PNG_USER_MEM_SUPPORTED */
667 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */