1
2 /* pngmem.c - stub functions for memory allocation
3 *
4 * Last changed in libpng 1.2.13 November 13, 2006
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2006 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 *
10 * This file provides a location for all memory allocation. Users who
11 * need special memory handling are expected to supply replacement
12 * functions for png_malloc() and png_free(), and to use
13 * png_create_read_struct_2() and png_create_write_struct_2() to
14 * identify the replacement functions.
15 */
16
17 #define PNG_INTERNAL
18 #include "png.h"
19
20 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
21
22 /* Borland DOS special memory handler */
23 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
24 /* if you change this, be sure to change the one in png.h also */
25
26 /* Allocate memory for a png_struct. The malloc and memset can be replaced
27 by a single call to calloc() if this is thought to improve performance. */
28 png_voidp /* PRIVATE */
png_create_struct(int type)29 png_create_struct(int type)
30 {
31 #ifdef PNG_USER_MEM_SUPPORTED
32 return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
33 }
34
35 /* Alternate version of png_create_struct, for use with user-defined malloc. */
36 png_voidp /* PRIVATE */
png_create_struct_2(int type,png_malloc_ptr malloc_fn,png_voidp mem_ptr)37 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
38 {
39 #endif /* PNG_USER_MEM_SUPPORTED */
40 png_size_t size;
41 png_voidp struct_ptr;
42
43 if (type == PNG_STRUCT_INFO)
44 size = png_sizeof(png_info);
45 else if (type == PNG_STRUCT_PNG)
46 size = png_sizeof(png_struct);
47 else
48 return (png_get_copyright(NULL));
49
50 #ifdef PNG_USER_MEM_SUPPORTED
51 if(malloc_fn != NULL)
52 {
53 png_struct dummy_struct;
54 png_structp png_ptr = &dummy_struct;
55 png_ptr->mem_ptr=mem_ptr;
56 struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
57 }
58 else
59 #endif /* PNG_USER_MEM_SUPPORTED */
60 struct_ptr = (png_voidp)farmalloc(size);
61 if (struct_ptr != NULL)
62 png_memset(struct_ptr, 0, size);
63 return (struct_ptr);
64 }
65
66 /* Free memory allocated by a png_create_struct() call */
67 void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)68 png_destroy_struct(png_voidp struct_ptr)
69 {
70 #ifdef PNG_USER_MEM_SUPPORTED
71 png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
72 }
73
74 /* Free memory allocated by a png_create_struct() call */
75 void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr,png_free_ptr free_fn,png_voidp mem_ptr)76 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
77 png_voidp mem_ptr)
78 {
79 #endif
80 if (struct_ptr != NULL)
81 {
82 #ifdef PNG_USER_MEM_SUPPORTED
83 if(free_fn != NULL)
84 {
85 png_struct dummy_struct;
86 png_structp png_ptr = &dummy_struct;
87 png_ptr->mem_ptr=mem_ptr;
88 (*(free_fn))(png_ptr, struct_ptr);
89 return;
90 }
91 #endif /* PNG_USER_MEM_SUPPORTED */
92 farfree (struct_ptr);
93 }
94 }
95
96 /* Allocate memory. For reasonable files, size should never exceed
97 * 64K. However, zlib may allocate more then 64K if you don't tell
98 * it not to. See zconf.h and png.h for more information. zlib does
99 * need to allocate exactly 64K, so whatever you call here must
100 * have the ability to do that.
101 *
102 * Borland seems to have a problem in DOS mode for exactly 64K.
103 * It gives you a segment with an offset of 8 (perhaps to store its
104 * memory stuff). zlib doesn't like this at all, so we have to
105 * detect and deal with it. This code should not be needed in
106 * Windows or OS/2 modes, and only in 16 bit mode. This code has
107 * been updated by Alexander Lehmann for version 0.89 to waste less
108 * memory.
109 *
110 * Note that we can't use png_size_t for the "size" declaration,
111 * since on some systems a png_size_t is a 16-bit quantity, and as a
112 * result, we would be truncating potentially larger memory requests
113 * (which should cause a fatal error) and introducing major problems.
114 */
115
116 png_voidp PNGAPI
png_malloc(png_structp png_ptr,png_uint_32 size)117 png_malloc(png_structp png_ptr, png_uint_32 size)
118 {
119 png_voidp ret;
120
121 if (png_ptr == NULL || size == 0)
122 return (NULL);
123
124 #ifdef PNG_USER_MEM_SUPPORTED
125 if(png_ptr->malloc_fn != NULL)
126 ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
127 else
128 ret = (png_malloc_default(png_ptr, size));
129 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
130 png_error(png_ptr, "Out of memory!");
131 return (ret);
132 }
133
134 png_voidp PNGAPI
png_malloc_default(png_structp png_ptr,png_uint_32 size)135 png_malloc_default(png_structp png_ptr, png_uint_32 size)
136 {
137 png_voidp ret;
138 #endif /* PNG_USER_MEM_SUPPORTED */
139
140 if (png_ptr == NULL || size == 0)
141 return (NULL);
142
143 #ifdef PNG_MAX_MALLOC_64K
144 if (size > (png_uint_32)65536L)
145 {
146 png_warning(png_ptr, "Cannot Allocate > 64K");
147 ret = NULL;
148 }
149 else
150 #endif
151
152 if (size != (size_t)size)
153 ret = NULL;
154 else if (size == (png_uint_32)65536L)
155 {
156 if (png_ptr->offset_table == NULL)
157 {
158 /* try to see if we need to do any of this fancy stuff */
159 ret = farmalloc(size);
160 if (ret == NULL || ((png_size_t)ret & 0xffff))
161 {
162 int num_blocks;
163 png_uint_32 total_size;
164 png_bytep table;
165 int i;
166 png_byte huge * hptr;
167
168 if (ret != NULL)
169 {
170 farfree(ret);
171 ret = NULL;
172 }
173
174 if(png_ptr->zlib_window_bits > 14)
175 num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
176 else
177 num_blocks = 1;
178 if (png_ptr->zlib_mem_level >= 7)
179 num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
180 else
181 num_blocks++;
182
183 total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
184
185 table = farmalloc(total_size);
186
187 if (table == NULL)
188 {
189 #ifndef PNG_USER_MEM_SUPPORTED
190 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
191 png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
192 else
193 png_warning(png_ptr, "Out Of Memory.");
194 #endif
195 return (NULL);
196 }
197
198 if ((png_size_t)table & 0xfff0)
199 {
200 #ifndef PNG_USER_MEM_SUPPORTED
201 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
202 png_error(png_ptr,
203 "Farmalloc didn't return normalized pointer");
204 else
205 png_warning(png_ptr,
206 "Farmalloc didn't return normalized pointer");
207 #endif
208 return (NULL);
209 }
210
211 png_ptr->offset_table = table;
212 png_ptr->offset_table_ptr = farmalloc(num_blocks *
213 png_sizeof (png_bytep));
214
215 if (png_ptr->offset_table_ptr == NULL)
216 {
217 #ifndef PNG_USER_MEM_SUPPORTED
218 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
219 png_error(png_ptr, "Out Of memory."); /* Note "O" and "M" */
220 else
221 png_warning(png_ptr, "Out Of memory.");
222 #endif
223 return (NULL);
224 }
225
226 hptr = (png_byte huge *)table;
227 if ((png_size_t)hptr & 0xf)
228 {
229 hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
230 hptr = hptr + 16L; /* "hptr += 16L" fails on Turbo C++ 3.0 */
231 }
232 for (i = 0; i < num_blocks; i++)
233 {
234 png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
235 hptr = hptr + (png_uint_32)65536L; /* "+=" fails on TC++3.0 */
236 }
237
238 png_ptr->offset_table_number = num_blocks;
239 png_ptr->offset_table_count = 0;
240 png_ptr->offset_table_count_free = 0;
241 }
242 }
243
244 if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
245 {
246 #ifndef PNG_USER_MEM_SUPPORTED
247 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
248 png_error(png_ptr, "Out of Memory."); /* Note "o" and "M" */
249 else
250 png_warning(png_ptr, "Out of Memory.");
251 #endif
252 return (NULL);
253 }
254
255 ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
256 }
257 else
258 ret = farmalloc(size);
259
260 #ifndef PNG_USER_MEM_SUPPORTED
261 if (ret == NULL)
262 {
263 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
264 png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
265 else
266 png_warning(png_ptr, "Out of memory."); /* Note "o" and "m" */
267 }
268 #endif
269
270 return (ret);
271 }
272
273 /* free a pointer allocated by png_malloc(). In the default
274 configuration, png_ptr is not used, but is passed in case it
275 is needed. If ptr is NULL, return without taking any action. */
276 void PNGAPI
png_free(png_structp png_ptr,png_voidp ptr)277 png_free(png_structp png_ptr, png_voidp ptr)
278 {
279 if (png_ptr == NULL || ptr == NULL)
280 return;
281
282 #ifdef PNG_USER_MEM_SUPPORTED
283 if (png_ptr->free_fn != NULL)
284 {
285 (*(png_ptr->free_fn))(png_ptr, ptr);
286 return;
287 }
288 else png_free_default(png_ptr, ptr);
289 }
290
291 void PNGAPI
png_free_default(png_structp png_ptr,png_voidp ptr)292 png_free_default(png_structp png_ptr, png_voidp ptr)
293 {
294 #endif /* PNG_USER_MEM_SUPPORTED */
295
296 if(png_ptr == NULL) return;
297
298 if (png_ptr->offset_table != NULL)
299 {
300 int i;
301
302 for (i = 0; i < png_ptr->offset_table_count; i++)
303 {
304 if (ptr == png_ptr->offset_table_ptr[i])
305 {
306 ptr = NULL;
307 png_ptr->offset_table_count_free++;
308 break;
309 }
310 }
311 if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
312 {
313 farfree(png_ptr->offset_table);
314 farfree(png_ptr->offset_table_ptr);
315 png_ptr->offset_table = NULL;
316 png_ptr->offset_table_ptr = NULL;
317 }
318 }
319
320 if (ptr != NULL)
321 {
322 farfree(ptr);
323 }
324 }
325
326 #else /* Not the Borland DOS special memory handler */
327
328 /* Allocate memory for a png_struct or a png_info. The malloc and
329 memset can be replaced by a single call to calloc() if this is thought
330 to improve performance noticably. */
331 png_voidp /* PRIVATE */
png_create_struct(int type)332 png_create_struct(int type)
333 {
334 #ifdef PNG_USER_MEM_SUPPORTED
335 return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
336 }
337
338 /* Allocate memory for a png_struct or a png_info. The malloc and
339 memset can be replaced by a single call to calloc() if this is thought
340 to improve performance noticably. */
341 png_voidp /* PRIVATE */
png_create_struct_2(int type,png_malloc_ptr malloc_fn,png_voidp mem_ptr)342 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
343 {
344 #endif /* PNG_USER_MEM_SUPPORTED */
345 png_size_t size;
346 png_voidp struct_ptr;
347
348 if (type == PNG_STRUCT_INFO)
349 size = png_sizeof(png_info);
350 else if (type == PNG_STRUCT_PNG)
351 size = png_sizeof(png_struct);
352 else
353 return (NULL);
354
355 #ifdef PNG_USER_MEM_SUPPORTED
356 if(malloc_fn != NULL)
357 {
358 png_struct dummy_struct;
359 png_structp png_ptr = &dummy_struct;
360 png_ptr->mem_ptr=mem_ptr;
361 struct_ptr = (*(malloc_fn))(png_ptr, size);
362 if (struct_ptr != NULL)
363 png_memset(struct_ptr, 0, size);
364 return (struct_ptr);
365 }
366 #endif /* PNG_USER_MEM_SUPPORTED */
367
368 #if defined(__TURBOC__) && !defined(__FLAT__)
369 struct_ptr = (png_voidp)farmalloc(size);
370 #else
371 # if defined(_MSC_VER) && defined(MAXSEG_64K)
372 struct_ptr = (png_voidp)halloc(size,1);
373 # else
374 struct_ptr = (png_voidp)malloc(size);
375 # endif
376 #endif
377 if (struct_ptr != NULL)
378 png_memset(struct_ptr, 0, size);
379
380 return (struct_ptr);
381 }
382
383
384 /* Free memory allocated by a png_create_struct() call */
385 void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)386 png_destroy_struct(png_voidp struct_ptr)
387 {
388 #ifdef PNG_USER_MEM_SUPPORTED
389 png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
390 }
391
392 /* Free memory allocated by a png_create_struct() call */
393 void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr,png_free_ptr free_fn,png_voidp mem_ptr)394 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
395 png_voidp mem_ptr)
396 {
397 #endif /* PNG_USER_MEM_SUPPORTED */
398 if (struct_ptr != NULL)
399 {
400 #ifdef PNG_USER_MEM_SUPPORTED
401 if(free_fn != NULL)
402 {
403 png_struct dummy_struct;
404 png_structp png_ptr = &dummy_struct;
405 png_ptr->mem_ptr=mem_ptr;
406 (*(free_fn))(png_ptr, struct_ptr);
407 return;
408 }
409 #endif /* PNG_USER_MEM_SUPPORTED */
410 #if defined(__TURBOC__) && !defined(__FLAT__)
411 farfree(struct_ptr);
412 #else
413 # if defined(_MSC_VER) && defined(MAXSEG_64K)
414 hfree(struct_ptr);
415 # else
416 free(struct_ptr);
417 # endif
418 #endif
419 }
420 }
421
422 /* Allocate memory. For reasonable files, size should never exceed
423 64K. However, zlib may allocate more then 64K if you don't tell
424 it not to. See zconf.h and png.h for more information. zlib does
425 need to allocate exactly 64K, so whatever you call here must
426 have the ability to do that. */
427
428 png_voidp PNGAPI
png_malloc(png_structp png_ptr,png_uint_32 size)429 png_malloc(png_structp png_ptr, png_uint_32 size)
430 {
431 png_voidp ret;
432
433 #ifdef PNG_USER_MEM_SUPPORTED
434 if (png_ptr == NULL || size == 0)
435 return (NULL);
436
437 if(png_ptr->malloc_fn != NULL)
438 ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
439 else
440 ret = (png_malloc_default(png_ptr, size));
441 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
442 png_error(png_ptr, "Out of Memory!");
443 return (ret);
444 }
445
446 png_voidp PNGAPI
png_malloc_default(png_structp png_ptr,png_uint_32 size)447 png_malloc_default(png_structp png_ptr, png_uint_32 size)
448 {
449 png_voidp ret;
450 #endif /* PNG_USER_MEM_SUPPORTED */
451
452 if (png_ptr == NULL || size == 0)
453 return (NULL);
454
455 #ifdef PNG_MAX_MALLOC_64K
456 if (size > (png_uint_32)65536L)
457 {
458 #ifndef PNG_USER_MEM_SUPPORTED
459 if(png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
460 png_error(png_ptr, "Cannot Allocate > 64K");
461 else
462 #endif
463 return NULL;
464 }
465 #endif
466
467 /* Check for overflow */
468 #if defined(__TURBOC__) && !defined(__FLAT__)
469 if (size != (unsigned long)size)
470 ret = NULL;
471 else
472 ret = farmalloc(size);
473 #else
474 # if defined(_MSC_VER) && defined(MAXSEG_64K)
475 if (size != (unsigned long)size)
476 ret = NULL;
477 else
478 ret = halloc(size, 1);
479 # else
480 if (size != (size_t)size)
481 ret = NULL;
482 else
483 ret = malloc((size_t)size);
484 # endif
485 #endif
486
487 #ifndef PNG_USER_MEM_SUPPORTED
488 if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
489 png_error(png_ptr, "Out of Memory");
490 #endif
491
492 return (ret);
493 }
494
495 /* Free a pointer allocated by png_malloc(). If ptr is NULL, return
496 without taking any action. */
497 void PNGAPI
png_free(png_structp png_ptr,png_voidp ptr)498 png_free(png_structp png_ptr, png_voidp ptr)
499 {
500 if (png_ptr == NULL || ptr == NULL)
501 return;
502
503 #ifdef PNG_USER_MEM_SUPPORTED
504 if (png_ptr->free_fn != NULL)
505 {
506 (*(png_ptr->free_fn))(png_ptr, ptr);
507 return;
508 }
509 else png_free_default(png_ptr, ptr);
510 }
511 void PNGAPI
png_free_default(png_structp png_ptr,png_voidp ptr)512 png_free_default(png_structp png_ptr, png_voidp ptr)
513 {
514 if (png_ptr == NULL || ptr == NULL)
515 return;
516
517 #endif /* PNG_USER_MEM_SUPPORTED */
518
519 #if defined(__TURBOC__) && !defined(__FLAT__)
520 farfree(ptr);
521 #else
522 # if defined(_MSC_VER) && defined(MAXSEG_64K)
523 hfree(ptr);
524 # else
525 free(ptr);
526 # endif
527 #endif
528 }
529
530 #endif /* Not Borland DOS special memory handler */
531
532 #if defined(PNG_1_0_X)
533 # define png_malloc_warn png_malloc
534 #else
535 /* This function was added at libpng version 1.2.3. The png_malloc_warn()
536 * function will set up png_malloc() to issue a png_warning and return NULL
537 * instead of issuing a png_error, if it fails to allocate the requested
538 * memory.
539 */
540 png_voidp PNGAPI
png_malloc_warn(png_structp png_ptr,png_uint_32 size)541 png_malloc_warn(png_structp png_ptr, png_uint_32 size)
542 {
543 png_voidp ptr;
544 png_uint_32 save_flags;
545 if(png_ptr == NULL) return (NULL);
546
547 save_flags=png_ptr->flags;
548 png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
549 ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
550 png_ptr->flags=save_flags;
551 return(ptr);
552 }
553 #endif
554
555 png_voidp PNGAPI
png_memcpy_check(png_structp png_ptr,png_voidp s1,png_voidp s2,png_uint_32 length)556 png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
557 png_uint_32 length)
558 {
559 png_size_t size;
560
561 size = (png_size_t)length;
562 if ((png_uint_32)size != length)
563 png_error(png_ptr,"Overflow in png_memcpy_check.");
564
565 return(png_memcpy (s1, s2, size));
566 }
567
568 png_voidp PNGAPI
png_memset_check(png_structp png_ptr,png_voidp s1,int value,png_uint_32 length)569 png_memset_check (png_structp png_ptr, png_voidp s1, int value,
570 png_uint_32 length)
571 {
572 png_size_t size;
573
574 size = (png_size_t)length;
575 if ((png_uint_32)size != length)
576 png_error(png_ptr,"Overflow in png_memset_check.");
577
578 return (png_memset (s1, value, size));
579
580 }
581
582 #ifdef PNG_USER_MEM_SUPPORTED
583 /* This function is called when the application wants to use another method
584 * of allocating and freeing memory.
585 */
586 void PNGAPI
png_set_mem_fn(png_structp png_ptr,png_voidp mem_ptr,png_malloc_ptr malloc_fn,png_free_ptr free_fn)587 png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
588 malloc_fn, png_free_ptr free_fn)
589 {
590 if(png_ptr != NULL) {
591 png_ptr->mem_ptr = mem_ptr;
592 png_ptr->malloc_fn = malloc_fn;
593 png_ptr->free_fn = free_fn;
594 }
595 }
596
597 /* This function returns a pointer to the mem_ptr associated with the user
598 * functions. The application should free any memory associated with this
599 * pointer before png_write_destroy and png_read_destroy are called.
600 */
601 png_voidp PNGAPI
png_get_mem_ptr(png_structp png_ptr)602 png_get_mem_ptr(png_structp png_ptr)
603 {
604 if(png_ptr == NULL) return (NULL);
605 return ((png_voidp)png_ptr->mem_ptr);
606 }
607 #endif /* PNG_USER_MEM_SUPPORTED */
608 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
609