mem.h (15521B)
1 /* 2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 /** 22 * @file 23 * memory handling functions 24 */ 25 26 #ifndef AVUTIL_MEM_H 27 #define AVUTIL_MEM_H 28 29 #include <limits.h> 30 #include <stdint.h> 31 32 #include "attributes.h" 33 #include "error.h" 34 #include "avutil.h" 35 36 /** 37 * @addtogroup lavu_mem 38 * @{ 39 */ 40 41 42 #if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C) 43 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v 44 #define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v 45 #elif defined(__TI_COMPILER_VERSION__) 46 #define DECLARE_ALIGNED(n,t,v) \ 47 AV_PRAGMA(DATA_ALIGN(v,n)) \ 48 t __attribute__((aligned(n))) v 49 #define DECLARE_ASM_CONST(n,t,v) \ 50 AV_PRAGMA(DATA_ALIGN(v,n)) \ 51 static const t __attribute__((aligned(n))) v 52 #elif defined(__GNUC__) 53 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v 54 #define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v 55 #elif defined(_MSC_VER) 56 #define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v 57 #define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v 58 #else 59 #define DECLARE_ALIGNED(n,t,v) t v 60 #define DECLARE_ASM_CONST(n,t,v) static const t v 61 #endif 62 63 #if AV_GCC_VERSION_AT_LEAST(3,1) 64 #define av_malloc_attrib __attribute__((__malloc__)) 65 #else 66 #define av_malloc_attrib 67 #endif 68 69 #if AV_GCC_VERSION_AT_LEAST(4,3) 70 #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__))) 71 #else 72 #define av_alloc_size(...) 73 #endif 74 75 /** 76 * Allocate a block of size bytes with alignment suitable for all 77 * memory accesses (including vectors if available on the CPU). 78 * @param size Size in bytes for the memory block to be allocated. 79 * @return Pointer to the allocated block, NULL if the block cannot 80 * be allocated. 81 * @see av_mallocz() 82 */ 83 void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1); 84 85 /** 86 * Allocate a block of size * nmemb bytes with av_malloc(). 87 * @param nmemb Number of elements 88 * @param size Size of the single element 89 * @return Pointer to the allocated block, NULL if the block cannot 90 * be allocated. 91 * @see av_malloc() 92 */ 93 av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size) 94 { 95 if (!size || nmemb >= INT_MAX / size) 96 return NULL; 97 return av_malloc(nmemb * size); 98 } 99 100 /** 101 * Allocate or reallocate a block of memory. 102 * If ptr is NULL and size > 0, allocate a new block. If 103 * size is zero, free the memory block pointed to by ptr. 104 * @param ptr Pointer to a memory block already allocated with 105 * av_realloc() or NULL. 106 * @param size Size in bytes of the memory block to be allocated or 107 * reallocated. 108 * @return Pointer to a newly-reallocated block or NULL if the block 109 * cannot be reallocated or the function is used to free the memory block. 110 * @warning Pointers originating from the av_malloc() family of functions must 111 * not be passed to av_realloc(). The former can be implemented using 112 * memalign() (or other functions), and there is no guarantee that 113 * pointers from such functions can be passed to realloc() at all. 114 * The situation is undefined according to POSIX and may crash with 115 * some libc implementations. 116 * @see av_fast_realloc() 117 */ 118 void *av_realloc(void *ptr, size_t size) av_alloc_size(2); 119 120 /** 121 * Allocate or reallocate a block of memory. 122 * This function does the same thing as av_realloc, except: 123 * - It takes two arguments and checks the result of the multiplication for 124 * integer overflow. 125 * - It frees the input block in case of failure, thus avoiding the memory 126 * leak with the classic "buf = realloc(buf); if (!buf) return -1;". 127 */ 128 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize); 129 130 /** 131 * Allocate or reallocate a block of memory. 132 * If *ptr is NULL and size > 0, allocate a new block. If 133 * size is zero, free the memory block pointed to by ptr. 134 * @param ptr Pointer to a pointer to a memory block already allocated 135 * with av_realloc(), or pointer to a pointer to NULL. 136 * The pointer is updated on success, or freed on failure. 137 * @param size Size in bytes for the memory block to be allocated or 138 * reallocated 139 * @return Zero on success, an AVERROR error code on failure. 140 * @warning Pointers originating from the av_malloc() family of functions must 141 * not be passed to av_reallocp(). The former can be implemented using 142 * memalign() (or other functions), and there is no guarantee that 143 * pointers from such functions can be passed to realloc() at all. 144 * The situation is undefined according to POSIX and may crash with 145 * some libc implementations. 146 */ 147 av_warn_unused_result 148 int av_reallocp(void *ptr, size_t size); 149 150 /** 151 * Allocate or reallocate an array. 152 * If ptr is NULL and nmemb > 0, allocate a new block. If 153 * nmemb is zero, free the memory block pointed to by ptr. 154 * @param ptr Pointer to a memory block already allocated with 155 * av_realloc() or NULL. 156 * @param nmemb Number of elements 157 * @param size Size of the single element 158 * @return Pointer to a newly-reallocated block or NULL if the block 159 * cannot be reallocated or the function is used to free the memory block. 160 * @warning Pointers originating from the av_malloc() family of functions must 161 * not be passed to av_realloc(). The former can be implemented using 162 * memalign() (or other functions), and there is no guarantee that 163 * pointers from such functions can be passed to realloc() at all. 164 * The situation is undefined according to POSIX and may crash with 165 * some libc implementations. 166 */ 167 av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size); 168 169 /** 170 * Allocate or reallocate an array through a pointer to a pointer. 171 * If *ptr is NULL and nmemb > 0, allocate a new block. If 172 * nmemb is zero, free the memory block pointed to by ptr. 173 * @param ptr Pointer to a pointer to a memory block already allocated 174 * with av_realloc(), or pointer to a pointer to NULL. 175 * The pointer is updated on success, or freed on failure. 176 * @param nmemb Number of elements 177 * @param size Size of the single element 178 * @return Zero on success, an AVERROR error code on failure. 179 * @warning Pointers originating from the av_malloc() family of functions must 180 * not be passed to av_realloc(). The former can be implemented using 181 * memalign() (or other functions), and there is no guarantee that 182 * pointers from such functions can be passed to realloc() at all. 183 * The situation is undefined according to POSIX and may crash with 184 * some libc implementations. 185 */ 186 av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size); 187 188 /** 189 * Free a memory block which has been allocated with av_malloc(z)() or 190 * av_realloc(). 191 * @param ptr Pointer to the memory block which should be freed. 192 * @note ptr = NULL is explicitly allowed. 193 * @note It is recommended that you use av_freep() instead. 194 * @see av_freep() 195 */ 196 void av_free(void *ptr); 197 198 /** 199 * Allocate a block of size bytes with alignment suitable for all 200 * memory accesses (including vectors if available on the CPU) and 201 * zero all the bytes of the block. 202 * @param size Size in bytes for the memory block to be allocated. 203 * @return Pointer to the allocated block, NULL if it cannot be allocated. 204 * @see av_malloc() 205 */ 206 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1); 207 208 /** 209 * Allocate a block of nmemb * size bytes with alignment suitable for all 210 * memory accesses (including vectors if available on the CPU) and 211 * zero all the bytes of the block. 212 * The allocation will fail if nmemb * size is greater than or equal 213 * to INT_MAX. 214 * @param nmemb 215 * @param size 216 * @return Pointer to the allocated block, NULL if it cannot be allocated. 217 */ 218 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib; 219 220 /** 221 * Allocate a block of size * nmemb bytes with av_mallocz(). 222 * @param nmemb Number of elements 223 * @param size Size of the single element 224 * @return Pointer to the allocated block, NULL if the block cannot 225 * be allocated. 226 * @see av_mallocz() 227 * @see av_malloc_array() 228 */ 229 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size) 230 { 231 if (!size || nmemb >= INT_MAX / size) 232 return NULL; 233 return av_mallocz(nmemb * size); 234 } 235 236 /** 237 * Duplicate the string s. 238 * @param s string to be duplicated 239 * @return Pointer to a newly-allocated string containing a 240 * copy of s or NULL if the string cannot be allocated. 241 */ 242 char *av_strdup(const char *s) av_malloc_attrib; 243 244 /** 245 * Duplicate a substring of the string s. 246 * @param s string to be duplicated 247 * @param len the maximum length of the resulting string (not counting the 248 * terminating byte). 249 * @return Pointer to a newly-allocated string containing a 250 * copy of s or NULL if the string cannot be allocated. 251 */ 252 char *av_strndup(const char *s, size_t len) av_malloc_attrib; 253 254 /** 255 * Duplicate the buffer p. 256 * @param p buffer to be duplicated 257 * @return Pointer to a newly allocated buffer containing a 258 * copy of p or NULL if the buffer cannot be allocated. 259 */ 260 void *av_memdup(const void *p, size_t size); 261 262 /** 263 * Free a memory block which has been allocated with av_malloc(z)() or 264 * av_realloc() and set the pointer pointing to it to NULL. 265 * @param ptr Pointer to the pointer to the memory block which should 266 * be freed. 267 * @note passing a pointer to a NULL pointer is safe and leads to no action. 268 * @see av_free() 269 */ 270 void av_freep(void *ptr); 271 272 /** 273 * Add an element to a dynamic array. 274 * 275 * The array to grow is supposed to be an array of pointers to 276 * structures, and the element to add must be a pointer to an already 277 * allocated structure. 278 * 279 * The array is reallocated when its size reaches powers of 2. 280 * Therefore, the amortized cost of adding an element is constant. 281 * 282 * In case of success, the pointer to the array is updated in order to 283 * point to the new grown array, and the number pointed to by nb_ptr 284 * is incremented. 285 * In case of failure, the array is freed, *tab_ptr is set to NULL and 286 * *nb_ptr is set to 0. 287 * 288 * @param tab_ptr pointer to the array to grow 289 * @param nb_ptr pointer to the number of elements in the array 290 * @param elem element to add 291 * @see av_dynarray_add_nofree(), av_dynarray2_add() 292 */ 293 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem); 294 295 /** 296 * Add an element to a dynamic array. 297 * 298 * Function has the same functionality as av_dynarray_add(), 299 * but it doesn't free memory on fails. It returns error code 300 * instead and leave current buffer untouched. 301 * 302 * @param tab_ptr pointer to the array to grow 303 * @param nb_ptr pointer to the number of elements in the array 304 * @param elem element to add 305 * @return >=0 on success, negative otherwise. 306 * @see av_dynarray_add(), av_dynarray2_add() 307 */ 308 av_warn_unused_result 309 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem); 310 311 /** 312 * Add an element of size elem_size to a dynamic array. 313 * 314 * The array is reallocated when its number of elements reaches powers of 2. 315 * Therefore, the amortized cost of adding an element is constant. 316 * 317 * In case of success, the pointer to the array is updated in order to 318 * point to the new grown array, and the number pointed to by nb_ptr 319 * is incremented. 320 * In case of failure, the array is freed, *tab_ptr is set to NULL and 321 * *nb_ptr is set to 0. 322 * 323 * @param tab_ptr pointer to the array to grow 324 * @param nb_ptr pointer to the number of elements in the array 325 * @param elem_size size in bytes of the elements in the array 326 * @param elem_data pointer to the data of the element to add. If NULL, the space of 327 * the new added element is not filled. 328 * @return pointer to the data of the element to copy in the new allocated space. 329 * If NULL, the new allocated space is left uninitialized." 330 * @see av_dynarray_add(), av_dynarray_add_nofree() 331 */ 332 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size, 333 const uint8_t *elem_data); 334 335 /** 336 * Multiply two size_t values checking for overflow. 337 * @return 0 if success, AVERROR(EINVAL) if overflow. 338 */ 339 static inline int av_size_mult(size_t a, size_t b, size_t *r) 340 { 341 size_t t = a * b; 342 /* Hack inspired from glibc: only try the division if nelem and elsize 343 * are both greater than sqrt(SIZE_MAX). */ 344 if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b) 345 return AVERROR(EINVAL); 346 *r = t; 347 return 0; 348 } 349 350 /** 351 * Set the maximum size that may me allocated in one block. 352 */ 353 void av_max_alloc(size_t max); 354 355 /** 356 * deliberately overlapping memcpy implementation 357 * @param dst destination buffer 358 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0 359 * @param cnt number of bytes to copy, must be >= 0 360 * 361 * cnt > back is valid, this will copy the bytes we just copied, 362 * thus creating a repeating pattern with a period length of back. 363 */ 364 void av_memcpy_backptr(uint8_t *dst, int back, int cnt); 365 366 /** 367 * Reallocate the given block if it is not large enough, otherwise do nothing. 368 * 369 * @see av_realloc 370 */ 371 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size); 372 373 /** 374 * Allocate a buffer, reusing the given one if large enough. 375 * 376 * Contrary to av_fast_realloc the current buffer contents might not be 377 * preserved and on error the old buffer is freed, thus no special 378 * handling to avoid memleaks is necessary. 379 * 380 * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer 381 * @param size size of the buffer *ptr points to 382 * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and 383 * *size 0 if an error occurred. 384 */ 385 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size); 386 387 /** 388 * Allocate a buffer, reusing the given one if large enough. 389 * 390 * All newly allocated space is initially cleared 391 * Contrary to av_fast_realloc the current buffer contents might not be 392 * preserved and on error the old buffer is freed, thus no special 393 * handling to avoid memleaks is necessary. 394 * 395 * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer 396 * @param size size of the buffer *ptr points to 397 * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and 398 * *size 0 if an error occurred. 399 */ 400 void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size); 401 402 /** 403 * @} 404 */ 405 406 #endif /* AVUTIL_MEM_H */