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1 /* pngmem.c - stub functions for memory allocation | |
2 * | |
3 * Last changed in libpng 1.6.0 [February 14, 2013] | |
4 * Copyright (c) 1998-2013 Glenn Randers-Pehrson | |
5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
7 * | |
8 * This code is released under the libpng license. | |
9 * For conditions of distribution and use, see the disclaimer | |
10 * and license in png.h | |
11 * | |
12 * This file provides a location for all memory allocation. Users who | |
13 * need special memory handling are expected to supply replacement | |
14 * functions for png_malloc() and png_free(), and to use | |
15 * png_create_read_struct_2() and png_create_write_struct_2() to | |
16 * identify the replacement functions. | |
17 */ | |
18 | |
19 #include "pngpriv.h" | |
20 | |
21 void* FXMEM_DefaultAlloc(int byte_size, int); | |
22 void FXMEM_DefaultFree(void* pointer, int); | |
23 | |
24 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
25 /* Free a png_struct */ | |
26 void /* PRIVATE */ | |
27 png_destroy_png_struct(png_structrp png_ptr) | |
28 { | |
29 if (png_ptr != NULL) | |
30 { | |
31 /* png_free might call png_error and may certainly call | |
32 * png_get_mem_ptr, so fake a temporary png_struct to support this. | |
33 */ | |
34 png_struct dummy_struct = *png_ptr; | |
35 memset(png_ptr, 0, (sizeof *png_ptr)); | |
36 png_free(&dummy_struct, png_ptr); | |
37 | |
38 # ifdef PNG_SETJMP_SUPPORTED | |
39 /* We may have a jmp_buf left to deallocate. */ | |
40 png_free_jmpbuf(&dummy_struct); | |
41 # endif | |
42 } | |
43 } | |
44 | |
45 /* Allocate memory. For reasonable files, size should never exceed | |
46 * 64K. However, zlib may allocate more then 64K if you don't tell | |
47 * it not to. See zconf.h and png.h for more information. zlib does | |
48 * need to allocate exactly 64K, so whatever you call here must | |
49 * have the ability to do that. | |
50 */ | |
51 PNG_FUNCTION(png_voidp,PNGAPI | |
52 png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) | |
53 { | |
54 png_voidp ret; | |
55 | |
56 ret = png_malloc(png_ptr, size); | |
57 | |
58 if (ret != NULL) | |
59 memset(ret, 0, size); | |
60 | |
61 return ret; | |
62 } | |
63 | |
64 /* png_malloc_base, an internal function added at libpng 1.6.0, does the work of | |
65 * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED. | |
66 * Checking and error handling must happen outside this routine; it returns NULL | |
67 * if the allocation cannot be done (for any reason.) | |
68 */ | |
69 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
70 png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size), | |
71 PNG_ALLOCATED) | |
72 { | |
73 /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS | |
74 * allocators have also been removed in 1.6.0, so any 16-bit system now has | |
75 * to implement a user memory handler. This checks to be sure it isn't | |
76 * called with big numbers. | |
77 */ | |
78 #ifdef PNG_USER_MEM_SUPPORTED | |
79 PNG_UNUSED(png_ptr) | |
80 #endif | |
81 if (size > 0 && size <= PNG_SIZE_MAX | |
82 # ifdef PNG_MAX_MALLOC_64K | |
83 && size <= 65536U | |
84 # endif | |
85 ) | |
86 { | |
87 #ifdef PNG_USER_MEM_SUPPORTED | |
88 if (png_ptr != NULL && png_ptr->malloc_fn != NULL) | |
89 return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size); | |
90 | |
91 else | |
92 #endif | |
93 return FXMEM_DefaultAlloc((int)size, 0); | |
94 //return malloc((size_t)size); /* checked for truncation above */ | |
95 } | |
96 | |
97 else | |
98 return NULL; | |
99 } | |
100 | |
101 /* This is really here only to work round a spurious warning in GCC 4.6 and 4.7 | |
102 * that arises because of the checks in png_realloc_array that are repeated in | |
103 * png_malloc_array. | |
104 */ | |
105 static png_voidp | |
106 png_malloc_array_checked(png_const_structrp png_ptr, int nelements, | |
107 size_t element_size) | |
108 { | |
109 png_alloc_size_t req = nelements; /* known to be > 0 */ | |
110 | |
111 if (req <= PNG_SIZE_MAX/element_size) | |
112 return png_malloc_base(png_ptr, req * element_size); | |
113 | |
114 /* The failure case when the request is too large */ | |
115 return NULL; | |
116 } | |
117 | |
118 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
119 png_malloc_array,(png_const_structrp png_ptr, int nelements, | |
120 size_t element_size),PNG_ALLOCATED) | |
121 { | |
122 if (nelements <= 0 || element_size == 0) | |
123 png_error(png_ptr, "internal error: array alloc"); | |
124 | |
125 return png_malloc_array_checked(png_ptr, nelements, element_size); | |
126 } | |
127 | |
128 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
129 png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array, | |
130 int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED) | |
131 { | |
132 /* These are internal errors: */ | |
133 if (add_elements <= 0 || element_size == 0 || old_elements < 0 || | |
134 (old_array == NULL && old_elements > 0)) | |
135 png_error(png_ptr, "internal error: array realloc"); | |
136 | |
137 /* Check for overflow on the elements count (so the caller does not have to | |
138 * check.) | |
139 */ | |
140 if (add_elements <= INT_MAX - old_elements) | |
141 { | |
142 png_voidp new_array = png_malloc_array_checked(png_ptr, | |
143 old_elements+add_elements, element_size); | |
144 | |
145 if (new_array != NULL) | |
146 { | |
147 /* Because png_malloc_array worked the size calculations below cannot | |
148 * overflow. | |
149 */ | |
150 if (old_elements > 0) | |
151 memcpy(new_array, old_array, element_size*(unsigned)old_elements); | |
152 | |
153 memset((char*)new_array + element_size*(unsigned)old_elements, 0, | |
154 element_size*(unsigned)add_elements); | |
155 | |
156 return new_array; | |
157 } | |
158 } | |
159 | |
160 return NULL; /* error */ | |
161 } | |
162 | |
163 /* Various functions that have different error handling are derived from this. | |
164 * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate | |
165 * function png_malloc_default is also provided. | |
166 */ | |
167 PNG_FUNCTION(png_voidp,PNGAPI | |
168 png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) | |
169 { | |
170 png_voidp ret; | |
171 | |
172 if (png_ptr == NULL) | |
173 return NULL; | |
174 | |
175 ret = png_malloc_base(png_ptr, size); | |
176 | |
177 if (ret == NULL) | |
178 png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */ | |
179 | |
180 return ret; | |
181 } | |
182 | |
183 #ifdef PNG_USER_MEM_SUPPORTED | |
184 PNG_FUNCTION(png_voidp,PNGAPI | |
185 png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size), | |
186 PNG_ALLOCATED PNG_DEPRECATED) | |
187 { | |
188 png_voidp ret; | |
189 | |
190 if (png_ptr == NULL) | |
191 return NULL; | |
192 | |
193 /* Passing 'NULL' here bypasses the application provided memory handler. */ | |
194 ret = png_malloc_base(NULL/*use malloc*/, size); | |
195 | |
196 if (ret == NULL) | |
197 png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */ | |
198 | |
199 return ret; | |
200 } | |
201 #endif /* PNG_USER_MEM_SUPPORTED */ | |
202 | |
203 /* This function was added at libpng version 1.2.3. The png_malloc_warn() | |
204 * function will issue a png_warning and return NULL instead of issuing a | |
205 * png_error, if it fails to allocate the requested memory. | |
206 */ | |
207 PNG_FUNCTION(png_voidp,PNGAPI | |
208 png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size), | |
209 PNG_ALLOCATED) | |
210 { | |
211 if (png_ptr != NULL) | |
212 { | |
213 png_voidp ret = png_malloc_base(png_ptr, size); | |
214 | |
215 if (ret != NULL) | |
216 return ret; | |
217 | |
218 png_warning(png_ptr, "Out of memory"); | |
219 } | |
220 | |
221 return NULL; | |
222 } | |
223 | |
224 /* Free a pointer allocated by png_malloc(). If ptr is NULL, return | |
225 * without taking any action. | |
226 */ | |
227 void PNGAPI | |
228 png_free(png_const_structrp png_ptr, png_voidp ptr) | |
229 { | |
230 if (png_ptr == NULL || ptr == NULL) | |
231 return; | |
232 | |
233 #ifdef PNG_USER_MEM_SUPPORTED | |
234 if (png_ptr->free_fn != NULL) | |
235 png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr); | |
236 | |
237 else | |
238 png_free_default(png_ptr, ptr); | |
239 } | |
240 | |
241 PNG_FUNCTION(void,PNGAPI | |
242 png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED) | |
243 { | |
244 if (png_ptr == NULL || ptr == NULL) | |
245 return; | |
246 #endif /* PNG_USER_MEM_SUPPORTED */ | |
247 | |
248 FXMEM_DefaultFree(ptr, 0); | |
249 //free(ptr); | |
250 } | |
251 | |
252 #ifdef PNG_USER_MEM_SUPPORTED | |
253 /* This function is called when the application wants to use another method | |
254 * of allocating and freeing memory. | |
255 */ | |
256 void PNGAPI | |
257 png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr | |
258 malloc_fn, png_free_ptr free_fn) | |
259 { | |
260 if (png_ptr != NULL) | |
261 { | |
262 png_ptr->mem_ptr = mem_ptr; | |
263 png_ptr->malloc_fn = malloc_fn; | |
264 png_ptr->free_fn = free_fn; | |
265 } | |
266 } | |
267 | |
268 /* This function returns a pointer to the mem_ptr associated with the user | |
269 * functions. The application should free any memory associated with this | |
270 * pointer before png_write_destroy and png_read_destroy are called. | |
271 */ | |
272 png_voidp PNGAPI | |
273 png_get_mem_ptr(png_const_structrp png_ptr) | |
274 { | |
275 if (png_ptr == NULL) | |
276 return NULL; | |
277 | |
278 return png_ptr->mem_ptr; | |
279 } | |
280 #endif /* PNG_USER_MEM_SUPPORTED */ | |
281 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ | |
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