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1 
2 /* pngmem.c - stub functions for memory allocation
3  *
4  * Last changed in libpng 1.2.41 [February 25, 2010]
5  * Copyright (c) 1998-2010 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 #define PNG_INTERNAL
21 #define PNG_NO_PEDANTIC_WARNINGS
22 #include "png.h"
23 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
24 
25 /* Borland DOS special memory handler */
26 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
27 /* If you change this, be sure to change the one in png.h also */
28 
29 /* Allocate memory for a png_struct.  The malloc and memset can be replaced
30    by a single call to calloc() if this is thought to improve performance. */
31 png_voidp /* PRIVATE */
png_create_struct(int type)32 png_create_struct(int type)
33 {
34 #ifdef PNG_USER_MEM_SUPPORTED
35    return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
36 }
37 
38 /* Alternate version of png_create_struct, for use with user-defined malloc. */
39 png_voidp /* PRIVATE */
png_create_struct_2(int type,png_malloc_ptr malloc_fn,png_voidp mem_ptr)40 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
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    else if (type == PNG_STRUCT_PNG)
49       size = png_sizeof(png_struct);
50    else
51       return (png_get_copyright(NULL));
52 
53 #ifdef PNG_USER_MEM_SUPPORTED
54    if (malloc_fn != NULL)
55    {
56       png_struct dummy_struct;
57       png_structp png_ptr = &dummy_struct;
58       png_ptr->mem_ptr=mem_ptr;
59       struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
60    }
61    else
62 #endif /* PNG_USER_MEM_SUPPORTED */
63    struct_ptr = (png_voidp)farmalloc(size);
64    if (struct_ptr != NULL)
65       png_memset(struct_ptr, 0, size);
66    return (struct_ptr);
67 }
68 
69 /* Free memory allocated by a png_create_struct() call */
70 void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)71 png_destroy_struct(png_voidp struct_ptr)
72 {
73 #ifdef PNG_USER_MEM_SUPPORTED
74    png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
75 }
76 
77 /* Free memory allocated by a png_create_struct() call */
78 void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr,png_free_ptr free_fn,png_voidp mem_ptr)79 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
80     png_voidp mem_ptr)
81 {
82 #endif
83    if (struct_ptr != NULL)
84    {
85 #ifdef PNG_USER_MEM_SUPPORTED
86       if (free_fn != NULL)
87       {
88          png_struct dummy_struct;
89          png_structp png_ptr = &dummy_struct;
90          png_ptr->mem_ptr=mem_ptr;
91          (*(free_fn))(png_ptr, struct_ptr);
92          return;
93       }
94 #endif /* PNG_USER_MEM_SUPPORTED */
95       farfree (struct_ptr);
96    }
97 }
98 
99 /* Allocate memory.  For reasonable files, size should never exceed
100  * 64K.  However, zlib may allocate more then 64K if you don't tell
101  * it not to.  See zconf.h and png.h for more information. zlib does
102  * need to allocate exactly 64K, so whatever you call here must
103  * have the ability to do that.
104  *
105  * Borland seems to have a problem in DOS mode for exactly 64K.
106  * It gives you a segment with an offset of 8 (perhaps to store its
107  * memory stuff).  zlib doesn't like this at all, so we have to
108  * detect and deal with it.  This code should not be needed in
109  * Windows or OS/2 modes, and only in 16 bit mode.  This code has
110  * been updated by Alexander Lehmann for version 0.89 to waste less
111  * memory.
112  *
113  * Note that we can't use png_size_t for the "size" declaration,
114  * since on some systems a png_size_t is a 16-bit quantity, and as a
115  * result, we would be truncating potentially larger memory requests
116  * (which should cause a fatal error) and introducing major problems.
117  */
118 png_voidp /* PRIVATE */
png_calloc(png_structp png_ptr,png_uint_32 size)119 png_calloc(png_structp png_ptr, png_uint_32 size)
120 {
121    png_voidp ret;
122 
123    ret = (png_malloc(png_ptr, size));
124    if (ret != NULL)
125       png_memset(ret,0,(png_size_t)size);
126    return (ret);
127 }
128 
129 png_voidp PNGAPI
png_malloc(png_structp png_ptr,png_uint_32 size)130 png_malloc(png_structp png_ptr, png_uint_32 size)
131 {
132    png_voidp ret;
133 
134    if (png_ptr == NULL || size == 0)
135       return (NULL);
136 
137 #ifdef PNG_USER_MEM_SUPPORTED
138    if (png_ptr->malloc_fn != NULL)
139       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
140    else
141       ret = (png_malloc_default(png_ptr, size));
142    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
143        png_error(png_ptr, "Out of memory!");
144    return (ret);
145 }
146 
147 png_voidp PNGAPI
png_malloc_default(png_structp png_ptr,png_uint_32 size)148 png_malloc_default(png_structp png_ptr, png_uint_32 size)
149 {
150    png_voidp ret;
151 #endif /* PNG_USER_MEM_SUPPORTED */
152 
153    if (png_ptr == NULL || size == 0)
154       return (NULL);
155 
156 #ifdef PNG_MAX_MALLOC_64K
157    if (size > (png_uint_32)65536L)
158    {
159       png_warning(png_ptr, "Cannot Allocate > 64K");
160       ret = NULL;
161    }
162    else
163 #endif
164 
165    if (size != (size_t)size)
166       ret = NULL;
167    else if (size == (png_uint_32)65536L)
168    {
169       if (png_ptr->offset_table == NULL)
170       {
171          /* Try to see if we need to do any of this fancy stuff */
172          ret = farmalloc(size);
173          if (ret == NULL || ((png_size_t)ret & 0xffff))
174          {
175             int num_blocks;
176             png_uint_32 total_size;
177             png_bytep table;
178             int i;
179             png_byte huge * hptr;
180 
181             if (ret != NULL)
182             {
183                farfree(ret);
184                ret = NULL;
185             }
186 
187             if (png_ptr->zlib_window_bits > 14)
188                num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
189             else
190                num_blocks = 1;
191             if (png_ptr->zlib_mem_level >= 7)
192                num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
193             else
194                num_blocks++;
195 
196             total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
197 
198             table = farmalloc(total_size);
199 
200             if (table == NULL)
201             {
202 #ifndef PNG_USER_MEM_SUPPORTED
203                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
204                   png_error(png_ptr, "Out Of Memory."); /* Note "O", "M" */
205                else
206                   png_warning(png_ptr, "Out Of Memory.");
207 #endif
208                return (NULL);
209             }
210 
211             if ((png_size_t)table & 0xfff0)
212             {
213 #ifndef PNG_USER_MEM_SUPPORTED
214                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
215                   png_error(png_ptr,
216                     "Farmalloc didn't return normalized pointer");
217                else
218                   png_warning(png_ptr,
219                     "Farmalloc didn't return normalized pointer");
220 #endif
221                return (NULL);
222             }
223 
224             png_ptr->offset_table = table;
225             png_ptr->offset_table_ptr = farmalloc(num_blocks *
226                png_sizeof(png_bytep));
227 
228             if (png_ptr->offset_table_ptr == NULL)
229             {
230 #ifndef PNG_USER_MEM_SUPPORTED
231                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
232                   png_error(png_ptr, "Out Of memory."); /* Note "O", "m" */
233                else
234                   png_warning(png_ptr, "Out Of memory.");
235 #endif
236                return (NULL);
237             }
238 
239             hptr = (png_byte huge *)table;
240             if ((png_size_t)hptr & 0xf)
241             {
242                hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
243                hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
244             }
245             for (i = 0; i < num_blocks; i++)
246             {
247                png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
248                hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
249             }
250 
251             png_ptr->offset_table_number = num_blocks;
252             png_ptr->offset_table_count = 0;
253             png_ptr->offset_table_count_free = 0;
254          }
255       }
256 
257       if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
258       {
259 #ifndef PNG_USER_MEM_SUPPORTED
260          if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
261             png_error(png_ptr, "Out of Memory."); /* Note "o" and "M" */
262          else
263             png_warning(png_ptr, "Out of Memory.");
264 #endif
265          return (NULL);
266       }
267 
268       ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
269    }
270    else
271       ret = farmalloc(size);
272 
273 #ifndef PNG_USER_MEM_SUPPORTED
274    if (ret == NULL)
275    {
276       if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
277          png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
278       else
279          png_warning(png_ptr, "Out of memory."); /* Note "o" and "m" */
280    }
281 #endif
282 
283    return (ret);
284 }
285 
286 /* Free a pointer allocated by png_malloc().  In the default
287  * configuration, png_ptr is not used, but is passed in case it
288  * is needed.  If ptr is NULL, return without taking any action.
289  */
290 void PNGAPI
png_free(png_structp png_ptr,png_voidp ptr)291 png_free(png_structp png_ptr, png_voidp ptr)
292 {
293    if (png_ptr == NULL || ptr == NULL)
294       return;
295 
296 #ifdef PNG_USER_MEM_SUPPORTED
297    if (png_ptr->free_fn != NULL)
298    {
299       (*(png_ptr->free_fn))(png_ptr, ptr);
300       return;
301    }
302    else
303       png_free_default(png_ptr, ptr);
304 }
305 
306 void PNGAPI
png_free_default(png_structp png_ptr,png_voidp ptr)307 png_free_default(png_structp png_ptr, png_voidp ptr)
308 {
309 #endif /* PNG_USER_MEM_SUPPORTED */
310 
311    if (png_ptr == NULL || ptr == NULL)
312       return;
313 
314    if (png_ptr->offset_table != NULL)
315    {
316       int i;
317 
318       for (i = 0; i < png_ptr->offset_table_count; i++)
319       {
320          if (ptr == png_ptr->offset_table_ptr[i])
321          {
322             ptr = NULL;
323             png_ptr->offset_table_count_free++;
324             break;
325          }
326       }
327       if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
328       {
329          farfree(png_ptr->offset_table);
330          farfree(png_ptr->offset_table_ptr);
331          png_ptr->offset_table = NULL;
332          png_ptr->offset_table_ptr = NULL;
333       }
334    }
335 
336    if (ptr != NULL)
337    {
338       farfree(ptr);
339    }
340 }
341 
342 #else /* Not the Borland DOS special memory handler */
343 
344 /* Allocate memory for a png_struct or a png_info.  The malloc and
345    memset can be replaced by a single call to calloc() if this is thought
346    to improve performance noticably. */
347 png_voidp /* PRIVATE */
png_create_struct(int type)348 png_create_struct(int type)
349 {
350 #ifdef PNG_USER_MEM_SUPPORTED
351    return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
352 }
353 
354 /* Allocate memory for a png_struct or a png_info.  The malloc and
355    memset can be replaced by a single call to calloc() if this is thought
356    to improve performance noticably. */
357 png_voidp /* PRIVATE */
png_create_struct_2(int type,png_malloc_ptr malloc_fn,png_voidp mem_ptr)358 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
359 {
360 #endif /* PNG_USER_MEM_SUPPORTED */
361    png_size_t size;
362    png_voidp struct_ptr;
363 
364    if (type == PNG_STRUCT_INFO)
365       size = png_sizeof(png_info);
366    else if (type == PNG_STRUCT_PNG)
367       size = png_sizeof(png_struct);
368    else
369       return (NULL);
370 
371 #ifdef PNG_USER_MEM_SUPPORTED
372    if (malloc_fn != NULL)
373    {
374       png_struct dummy_struct;
375       png_structp png_ptr = &dummy_struct;
376       png_ptr->mem_ptr=mem_ptr;
377       struct_ptr = (*(malloc_fn))(png_ptr, size);
378       if (struct_ptr != NULL)
379          png_memset(struct_ptr, 0, size);
380       return (struct_ptr);
381    }
382 #endif /* PNG_USER_MEM_SUPPORTED */
383 
384 #if defined(__TURBOC__) && !defined(__FLAT__)
385    struct_ptr = (png_voidp)farmalloc(size);
386 #else
387 # if defined(_MSC_VER) && defined(MAXSEG_64K)
388    struct_ptr = (png_voidp)halloc(size, 1);
389 # else
390    struct_ptr = (png_voidp)malloc(size);
391 # endif
392 #endif
393    if (struct_ptr != NULL)
394       png_memset(struct_ptr, 0, size);
395 
396    return (struct_ptr);
397 }
398 
399 
400 /* Free memory allocated by a png_create_struct() call */
401 void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)402 png_destroy_struct(png_voidp struct_ptr)
403 {
404 #ifdef PNG_USER_MEM_SUPPORTED
405    png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
406 }
407 
408 /* Free memory allocated by a png_create_struct() call */
409 void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr,png_free_ptr free_fn,png_voidp mem_ptr)410 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
411     png_voidp mem_ptr)
412 {
413 #endif /* PNG_USER_MEM_SUPPORTED */
414    if (struct_ptr != NULL)
415    {
416 #ifdef PNG_USER_MEM_SUPPORTED
417       if (free_fn != NULL)
418       {
419          png_struct dummy_struct;
420          png_structp png_ptr = &dummy_struct;
421          png_ptr->mem_ptr=mem_ptr;
422          (*(free_fn))(png_ptr, struct_ptr);
423          return;
424       }
425 #endif /* PNG_USER_MEM_SUPPORTED */
426 #if defined(__TURBOC__) && !defined(__FLAT__)
427       farfree(struct_ptr);
428 #else
429 # if defined(_MSC_VER) && defined(MAXSEG_64K)
430       hfree(struct_ptr);
431 # else
432       free(struct_ptr);
433 # endif
434 #endif
435    }
436 }
437 
438 /* Allocate memory.  For reasonable files, size should never exceed
439  * 64K.  However, zlib may allocate more then 64K if you don't tell
440  * it not to.  See zconf.h and png.h for more information.  zlib does
441  * need to allocate exactly 64K, so whatever you call here must
442  * have the ability to do that.
443  */
444 
445 png_voidp /* PRIVATE */
png_calloc(png_structp png_ptr,png_uint_32 size)446 png_calloc(png_structp png_ptr, png_uint_32 size)
447 {
448    png_voidp ret;
449 
450    ret = (png_malloc(png_ptr, size));
451    if (ret != NULL)
452       png_memset(ret,0,(png_size_t)size);
453    return (ret);
454 }
455 
456 png_voidp PNGAPI
png_malloc(png_structp png_ptr,png_uint_32 size)457 png_malloc(png_structp png_ptr, png_uint_32 size)
458 {
459    png_voidp ret;
460 
461 #ifdef PNG_USER_MEM_SUPPORTED
462    if (png_ptr == NULL || size == 0)
463       return (NULL);
464 
465    if (png_ptr->malloc_fn != NULL)
466       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
467    else
468       ret = (png_malloc_default(png_ptr, size));
469    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
470        png_error(png_ptr, "Out of Memory!");
471    return (ret);
472 }
473 
474 png_voidp PNGAPI
png_malloc_default(png_structp png_ptr,png_uint_32 size)475 png_malloc_default(png_structp png_ptr, png_uint_32 size)
476 {
477    png_voidp ret;
478 #endif /* PNG_USER_MEM_SUPPORTED */
479 
480    if (png_ptr == NULL || size == 0)
481       return (NULL);
482 
483 #ifdef PNG_MAX_MALLOC_64K
484    if (size > (png_uint_32)65536L)
485    {
486 #ifndef PNG_USER_MEM_SUPPORTED
487       if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
488          png_error(png_ptr, "Cannot Allocate > 64K");
489       else
490 #endif
491          return NULL;
492    }
493 #endif
494 
495    /* Check for overflow */
496 #if defined(__TURBOC__) && !defined(__FLAT__)
497    if (size != (unsigned long)size)
498       ret = NULL;
499    else
500       ret = farmalloc(size);
501 #else
502 # if defined(_MSC_VER) && defined(MAXSEG_64K)
503    if (size != (unsigned long)size)
504       ret = NULL;
505    else
506       ret = halloc(size, 1);
507 # else
508    if (size != (size_t)size)
509       ret = NULL;
510    else
511       ret = malloc((size_t)size);
512 # endif
513 #endif
514 
515 #ifndef PNG_USER_MEM_SUPPORTED
516    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
517       png_error(png_ptr, "Out of Memory");
518 #endif
519 
520    return (ret);
521 }
522 
523 /* Free a pointer allocated by png_malloc().  If ptr is NULL, return
524  * without taking any action.
525  */
526 void PNGAPI
png_free(png_structp png_ptr,png_voidp ptr)527 png_free(png_structp png_ptr, png_voidp ptr)
528 {
529    if (png_ptr == NULL || ptr == NULL)
530       return;
531 
532 #ifdef PNG_USER_MEM_SUPPORTED
533    if (png_ptr->free_fn != NULL)
534    {
535       (*(png_ptr->free_fn))(png_ptr, ptr);
536       return;
537    }
538    else
539       png_free_default(png_ptr, ptr);
540 }
541 void PNGAPI
png_free_default(png_structp png_ptr,png_voidp ptr)542 png_free_default(png_structp png_ptr, png_voidp ptr)
543 {
544    if (png_ptr == NULL || ptr == NULL)
545       return;
546 
547 #endif /* PNG_USER_MEM_SUPPORTED */
548 
549 #if defined(__TURBOC__) && !defined(__FLAT__)
550    farfree(ptr);
551 #else
552 # if defined(_MSC_VER) && defined(MAXSEG_64K)
553    hfree(ptr);
554 # else
555    free(ptr);
556 # endif
557 #endif
558 }
559 
560 #endif /* Not Borland DOS special memory handler */
561 
562 #ifdef PNG_1_0_X
563 #  define png_malloc_warn png_malloc
564 #else
565 /* This function was added at libpng version 1.2.3.  The png_malloc_warn()
566  * function will set up png_malloc() to issue a png_warning and return NULL
567  * instead of issuing a png_error, if it fails to allocate the requested
568  * memory.
569  */
570 png_voidp PNGAPI
png_malloc_warn(png_structp png_ptr,png_uint_32 size)571 png_malloc_warn(png_structp png_ptr, png_uint_32 size)
572 {
573    png_voidp ptr;
574    png_uint_32 save_flags;
575    if (png_ptr == NULL)
576       return (NULL);
577 
578    save_flags = png_ptr->flags;
579    png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
580    ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
581    png_ptr->flags=save_flags;
582    return(ptr);
583 }
584 #endif
585 
586 png_voidp PNGAPI
png_memcpy_check(png_structp png_ptr,png_voidp s1,png_voidp s2,png_uint_32 length)587 png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
588    png_uint_32 length)
589 {
590    png_size_t size;
591 
592    size = (png_size_t)length;
593    if ((png_uint_32)size != length)
594       png_error(png_ptr, "Overflow in png_memcpy_check.");
595 
596    return(png_memcpy (s1, s2, size));
597 }
598 
599 png_voidp PNGAPI
png_memset_check(png_structp png_ptr,png_voidp s1,int value,png_uint_32 length)600 png_memset_check (png_structp png_ptr, png_voidp s1, int value,
601    png_uint_32 length)
602 {
603    png_size_t size;
604 
605    size = (png_size_t)length;
606    if ((png_uint_32)size != length)
607       png_error(png_ptr, "Overflow in png_memset_check.");
608 
609    return (png_memset (s1, value, size));
610 
611 }
612 
613 #ifdef PNG_USER_MEM_SUPPORTED
614 /* This function is called when the application wants to use another method
615  * of allocating and freeing memory.
616  */
617 void PNGAPI
png_set_mem_fn(png_structp png_ptr,png_voidp mem_ptr,png_malloc_ptr malloc_fn,png_free_ptr free_fn)618 png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
619   malloc_fn, png_free_ptr free_fn)
620 {
621    if (png_ptr != NULL)
622    {
623       png_ptr->mem_ptr = mem_ptr;
624       png_ptr->malloc_fn = malloc_fn;
625       png_ptr->free_fn = free_fn;
626    }
627 }
628 
629 /* This function returns a pointer to the mem_ptr associated with the user
630  * functions.  The application should free any memory associated with this
631  * pointer before png_write_destroy and png_read_destroy are called.
632  */
633 png_voidp PNGAPI
png_get_mem_ptr(png_structp png_ptr)634 png_get_mem_ptr(png_structp png_ptr)
635 {
636    if (png_ptr == NULL)
637       return (NULL);
638    return ((png_voidp)png_ptr->mem_ptr);
639 }
640 #endif /* PNG_USER_MEM_SUPPORTED */
641 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
642