2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
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.
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.
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
23 * memory handling functions
32 #include "attributes.h"
37 * @addtogroup lavu_mem
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
59 #define DECLARE_ALIGNED(n,t,v) t v
60 #define DECLARE_ASM_CONST(n,t,v) static const t v
63 #if AV_GCC_VERSION_AT_LEAST(3,1)
64 #define av_malloc_attrib __attribute__((__malloc__))
66 #define av_malloc_attrib
69 #if AV_GCC_VERSION_AT_LEAST(4,3)
70 #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
72 #define av_alloc_size(...)
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
83 void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);
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
93 av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
95 if (!size || nmemb >= INT_MAX / size)
97 return av_malloc(nmemb * size);
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
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()
118 void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
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
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;".
128 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
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
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.
147 av_warn_unused_result
148 int av_reallocp(void *ptr, size_t size);
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.
167 av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
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.
186 av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
189 * Free a memory block which has been allocated with av_malloc(z)() or
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.
196 void av_free(void *ptr);
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.
206 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
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
216 * @return Pointer to the allocated block, NULL if it cannot be allocated.
218 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
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
227 * @see av_malloc_array()
229 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
231 if (!size || nmemb >= INT_MAX / size)
233 return av_mallocz(nmemb * size);
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.
242 char *av_strdup(const char *s) av_malloc_attrib;
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
249 * @return Pointer to a newly-allocated string containing a
250 * copy of s or NULL if the string cannot be allocated.
252 char *av_strndup(const char *s, size_t len) av_malloc_attrib;
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.
260 void *av_memdup(const void *p, size_t size);
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
267 * @note passing a pointer to a NULL pointer is safe and leads to no action.
270 void av_freep(void *ptr);
273 * Add an element to a dynamic array.
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.
279 * The array is reallocated when its size reaches powers of 2.
280 * Therefore, the amortized cost of adding an element is constant.
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
285 * In case of failure, the array is freed, *tab_ptr is set to NULL and
286 * *nb_ptr is set to 0.
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()
293 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
296 * Add an element to a dynamic array.
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.
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()
308 av_warn_unused_result
309 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem);
312 * Add an element of size elem_size to a dynamic array.
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.
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
320 * In case of failure, the array is freed, *tab_ptr is set to NULL and
321 * *nb_ptr is set to 0.
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()
332 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
333 const uint8_t *elem_data);
336 * Multiply two size_t values checking for overflow.
337 * @return 0 if success, AVERROR(EINVAL) if overflow.
339 static inline int av_size_mult(size_t a, size_t b, size_t *r)
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);
351 * Set the maximum size that may me allocated in one block.
353 void av_max_alloc(size_t max);
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
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.
364 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
367 * Reallocate the given block if it is not large enough, otherwise do nothing.
371 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
374 * Allocate a buffer, reusing the given one if large enough.
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.
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.
385 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
391 #endif /* AVUTIL_MEM_H */