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| 1 | |
| 2 /* pngmem.c - stub functions for memory allocation | |
| 3 * | |
| 4 * Last changed in libpng 1.6.15 [November 20, 2014] | |
| 5 * Copyright (c) 1998-2014 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 void* FXMEM_DefaultAlloc(int byte_size, int); | |
| 23 void FXMEM_DefaultFree(void* pointer, int); | |
| 24 | |
| 25 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
| 26 /* Free a png_struct */ | |
| 27 void /* PRIVATE */ | |
| 28 png_destroy_png_struct(png_structrp png_ptr) | |
| 29 { | |
| 30 if (png_ptr != NULL) | |
| 31 { | |
| 32 /* png_free might call png_error and may certainly call | |
| 33 * png_get_mem_ptr, so fake a temporary png_struct to support this. | |
| 34 */ | |
| 35 png_struct dummy_struct = *png_ptr; | |
| 36 memset(png_ptr, 0, (sizeof *png_ptr)); | |
| 37 png_free(&dummy_struct, png_ptr); | |
| 38 | |
| 39 # ifdef PNG_SETJMP_SUPPORTED | |
| 40 /* We may have a jmp_buf left to deallocate. */ | |
| 41 png_free_jmpbuf(&dummy_struct); | |
| 42 # endif | |
| 43 } | |
| 44 } | |
| 45 | |
| 46 /* Allocate memory. For reasonable files, size should never exceed | |
| 47 * 64K. However, zlib may allocate more than 64K if you don't tell | |
| 48 * it not to. See zconf.h and png.h for more information. zlib does | |
| 49 * need to allocate exactly 64K, so whatever you call here must | |
| 50 * have the ability to do that. | |
| 51 */ | |
| 52 PNG_FUNCTION(png_voidp,PNGAPI | |
| 53 png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) | |
| 54 { | |
| 55 png_voidp ret; | |
| 56 | |
| 57 ret = png_malloc(png_ptr, size); | |
| 58 | |
| 59 if (ret != NULL) | |
| 60 memset(ret, 0, size); | |
| 61 | |
| 62 return ret; | |
| 63 } | |
| 64 | |
| 65 /* png_malloc_base, an internal function added at libpng 1.6.0, does the work of | |
| 66 * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED. | |
| 67 * Checking and error handling must happen outside this routine; it returns NULL | |
| 68 * if the allocation cannot be done (for any reason.) | |
| 69 */ | |
| 70 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
| 71 png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size), | |
| 72 PNG_ALLOCATED) | |
| 73 { | |
| 74 /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS | |
| 75 * allocators have also been removed in 1.6.0, so any 16-bit system now has | |
| 76 * to implement a user memory handler. This checks to be sure it isn't | |
| 77 * called with big numbers. | |
| 78 */ | |
| 79 #ifndef PNG_USER_MEM_SUPPORTED | |
| 80 PNG_UNUSED(png_ptr) | |
| 81 #endif | |
| 82 | |
| 83 /* Some compilers complain that this is always true. However, it | |
| 84 * can be false when integer overflow happens. | |
| 85 */ | |
| 86 if (size > 0 && size <= PNG_SIZE_MAX | |
| 87 # ifdef PNG_MAX_MALLOC_64K | |
| 88 && size <= 65536U | |
| 89 # endif | |
| 90 ) | |
| 91 { | |
| 92 #ifdef PNG_USER_MEM_SUPPORTED | |
| 93 if (png_ptr != NULL && png_ptr->malloc_fn != NULL) | |
| 94 return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size); | |
| 95 | |
| 96 else | |
| 97 #endif | |
| 98 return FXMEM_DefaultAlloc((int)size, 0); | |
| 99 } | |
| 100 | |
| 101 else | |
| 102 return NULL; | |
| 103 } | |
| 104 | |
| 105 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\ | |
| 106 defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) | |
| 107 /* This is really here only to work round a spurious warning in GCC 4.6 and 4.7 | |
| 108 * that arises because of the checks in png_realloc_array that are repeated in | |
| 109 * png_malloc_array. | |
| 110 */ | |
| 111 static png_voidp | |
| 112 png_malloc_array_checked(png_const_structrp png_ptr, int nelements, | |
| 113 size_t element_size) | |
| 114 { | |
| 115 png_alloc_size_t req = nelements; /* known to be > 0 */ | |
| 116 | |
| 117 if (req <= PNG_SIZE_MAX/element_size) | |
| 118 return png_malloc_base(png_ptr, req * element_size); | |
| 119 | |
| 120 /* The failure case when the request is too large */ | |
| 121 return NULL; | |
| 122 } | |
| 123 | |
| 124 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
| 125 png_malloc_array,(png_const_structrp png_ptr, int nelements, | |
| 126 size_t element_size),PNG_ALLOCATED) | |
| 127 { | |
| 128 if (nelements <= 0 || element_size == 0) | |
| 129 png_error(png_ptr, "internal error: array alloc"); | |
| 130 | |
| 131 return png_malloc_array_checked(png_ptr, nelements, element_size); | |
| 132 } | |
| 133 | |
| 134 PNG_FUNCTION(png_voidp /* PRIVATE */, | |
| 135 png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array, | |
| 136 int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED) | |
| 137 { | |
| 138 /* These are internal errors: */ | |
| 139 if (add_elements <= 0 || element_size == 0 || old_elements < 0 || | |
| 140 (old_array == NULL && old_elements > 0)) | |
| 141 png_error(png_ptr, "internal error: array realloc"); | |
| 142 | |
| 143 /* Check for overflow on the elements count (so the caller does not have to | |
| 144 * check.) | |
| 145 */ | |
| 146 if (add_elements <= INT_MAX - old_elements) | |
| 147 { | |
| 148 png_voidp new_array = png_malloc_array_checked(png_ptr, | |
| 149 old_elements+add_elements, element_size); | |
| 150 | |
| 151 if (new_array != NULL) | |
| 152 { | |
| 153 /* Because png_malloc_array worked the size calculations below cannot | |
| 154 * overflow. | |
| 155 */ | |
| 156 if (old_elements > 0) | |
| 157 memcpy(new_array, old_array, element_size*(unsigned)old_elements); | |
| 158 | |
| 159 memset((char*)new_array + element_size*(unsigned)old_elements, 0, | |
| 160 element_size*(unsigned)add_elements); | |
| 161 | |
| 162 return new_array; | |
| 163 } | |
| 164 } | |
| 165 | |
| 166 return NULL; /* error */ | |
| 167 } | |
| 168 #endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */ | |
| 169 | |
| 170 /* Various functions that have different error handling are derived from this. | |
| 171 * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate | |
| 172 * function png_malloc_default is also provided. | |
| 173 */ | |
| 174 PNG_FUNCTION(png_voidp,PNGAPI | |
| 175 png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) | |
| 176 { | |
| 177 png_voidp ret; | |
| 178 | |
| 179 if (png_ptr == NULL) | |
| 180 return NULL; | |
| 181 | |
| 182 ret = png_malloc_base(png_ptr, size); | |
| 183 | |
| 184 if (ret == NULL) | |
| 185 png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */ | |
| 186 | |
| 187 return ret; | |
| 188 } | |
| 189 | |
| 190 #ifdef PNG_USER_MEM_SUPPORTED | |
| 191 PNG_FUNCTION(png_voidp,PNGAPI | |
| 192 png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size), | |
| 193 PNG_ALLOCATED PNG_DEPRECATED) | |
| 194 { | |
| 195 png_voidp ret; | |
| 196 | |
| 197 if (png_ptr == NULL) | |
| 198 return NULL; | |
| 199 | |
| 200 /* Passing 'NULL' here bypasses the application provided memory handler. */ | |
| 201 ret = png_malloc_base(NULL/*use malloc*/, size); | |
| 202 | |
| 203 if (ret == NULL) | |
| 204 png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */ | |
| 205 | |
| 206 return ret; | |
| 207 } | |
| 208 #endif /* USER_MEM */ | |
| 209 | |
| 210 /* This function was added at libpng version 1.2.3. The png_malloc_warn() | |
| 211 * function will issue a png_warning and return NULL instead of issuing a | |
| 212 * png_error, if it fails to allocate the requested memory. | |
| 213 */ | |
| 214 PNG_FUNCTION(png_voidp,PNGAPI | |
| 215 png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size), | |
| 216 PNG_ALLOCATED) | |
| 217 { | |
| 218 if (png_ptr != NULL) | |
| 219 { | |
| 220 png_voidp ret = png_malloc_base(png_ptr, size); | |
| 221 | |
| 222 if (ret != NULL) | |
| 223 return ret; | |
| 224 | |
| 225 png_warning(png_ptr, "Out of memory"); | |
| 226 } | |
| 227 | |
| 228 return NULL; | |
| 229 } | |
| 230 | |
| 231 /* Free a pointer allocated by png_malloc(). If ptr is NULL, return | |
| 232 * without taking any action. | |
| 233 */ | |
| 234 void PNGAPI | |
| 235 png_free(png_const_structrp png_ptr, png_voidp ptr) | |
| 236 { | |
| 237 if (png_ptr == NULL || ptr == NULL) | |
| 238 return; | |
| 239 | |
| 240 #ifdef PNG_USER_MEM_SUPPORTED | |
| 241 if (png_ptr->free_fn != NULL) | |
| 242 png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr); | |
| 243 | |
| 244 else | |
| 245 png_free_default(png_ptr, ptr); | |
| 246 } | |
| 247 | |
| 248 PNG_FUNCTION(void,PNGAPI | |
| 249 png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED) | |
| 250 { | |
| 251 if (png_ptr == NULL || ptr == NULL) | |
| 252 return; | |
| 253 #endif /* USER_MEM */ | |
| 254 | |
| 255 FXMEM_DefaultFree(ptr, 0); | |
| 256 } | |
| 257 | |
| 258 #ifdef PNG_USER_MEM_SUPPORTED | |
| 259 /* This function is called when the application wants to use another method | |
| 260 * of allocating and freeing memory. | |
| 261 */ | |
| 262 void PNGAPI | |
| 263 png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr | |
| 264 malloc_fn, png_free_ptr free_fn) | |
| 265 { | |
| 266 if (png_ptr != NULL) | |
| 267 { | |
| 268 png_ptr->mem_ptr = mem_ptr; | |
| 269 png_ptr->malloc_fn = malloc_fn; | |
| 270 png_ptr->free_fn = free_fn; | |
| 271 } | |
| 272 } | |
| 273 | |
| 274 /* This function returns a pointer to the mem_ptr associated with the user | |
| 275 * functions. The application should free any memory associated with this | |
| 276 * pointer before png_write_destroy and png_read_destroy are called. | |
| 277 */ | |
| 278 png_voidp PNGAPI | |
| 279 png_get_mem_ptr(png_const_structrp png_ptr) | |
| 280 { | |
| 281 if (png_ptr == NULL) | |
| 282 return NULL; | |
| 283 | |
| 284 return png_ptr->mem_ptr; | |
| 285 } | |
| 286 #endif /* USER_MEM */ | |
| 287 #endif /* READ || WRITE */ | |
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