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 * Helper function to allocate a block of size * nmemb bytes with
88 * @param nmemb Number of elements
89 * @param size Size of the single element
90 * @return Pointer to the allocated block, NULL if the block cannot
94 av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
96 if (size <= 0 || nmemb >= INT_MAX / size)
98 return av_malloc(nmemb * size);
102 * Allocate or reallocate a block of memory.
103 * If ptr is NULL and size > 0, allocate a new block. If
104 * size is zero, free the memory block pointed to by ptr.
105 * @param ptr Pointer to a memory block already allocated with
106 * av_malloc(z)() or av_realloc() or NULL.
107 * @param size Size in bytes for the memory block to be allocated or
109 * @return Pointer to a newly reallocated block or NULL if the block
110 * cannot be reallocated or the function is used to free the memory block.
111 * @see av_fast_realloc()
113 void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
116 * Allocate or reallocate a block of memory.
117 * This function does the same thing as av_realloc, except:
118 * - It takes two arguments and checks the result of the multiplication for
120 * - It frees the input block in case of failure, thus avoiding the memory
121 * leak with the classic "buf = realloc(buf); if (!buf) return -1;".
123 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
126 * Allocate or reallocate an array.
127 * If ptr is NULL and nmemb > 0, allocate a new block. If
128 * nmemb is zero, free the memory block pointed to by ptr.
129 * @param ptr Pointer to a memory block already allocated with
130 * av_malloc(z)() or av_realloc() or NULL.
131 * @param nmemb Number of elements
132 * @param size Size of the single element
133 * @return Pointer to a newly reallocated block or NULL if the block
134 * cannot be reallocated or the function is used to free the memory block.
136 av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
139 * Allocate or reallocate an array.
140 * If *ptr is NULL and nmemb > 0, allocate a new block. If
141 * nmemb is zero, free the memory block pointed to by ptr.
142 * @param ptr Pointer to a pointer to a memory block already allocated
143 * with av_malloc(z)() or av_realloc(), or pointer to a pointer to NULL.
144 * The pointer is updated on success, or freed on failure.
145 * @param nmemb Number of elements
146 * @param size Size of the single element
147 * @return Zero on success, an AVERROR error code on failure.
149 av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
152 * Free a memory block which has been allocated with av_malloc(z)() or
154 * @param ptr Pointer to the memory block which should be freed.
155 * @note ptr = NULL is explicitly allowed.
156 * @note It is recommended that you use av_freep() instead.
159 void av_free(void *ptr);
162 * Allocate a block of size bytes with alignment suitable for all
163 * memory accesses (including vectors if available on the CPU) and
164 * zero all the bytes of the block.
165 * @param size Size in bytes for the memory block to be allocated.
166 * @return Pointer to the allocated block, NULL if it cannot be allocated.
169 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
172 * Allocate a block of nmemb * size bytes with alignment suitable for all
173 * memory accesses (including vectors if available on the CPU) and
174 * zero all the bytes of the block.
175 * The allocation will fail if nmemb * size is greater than or equal
179 * @return Pointer to the allocated block, NULL if it cannot be allocated.
181 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
184 * Helper function to allocate a block of size * nmemb bytes with
186 * @param nmemb Number of elements
187 * @param size Size of the single element
188 * @return Pointer to the allocated block, NULL if the block cannot
191 * @see av_malloc_array()
193 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
195 if (size <= 0 || nmemb >= INT_MAX / size)
197 return av_mallocz(nmemb * size);
201 * Duplicate the string s.
202 * @param s string to be duplicated
203 * @return Pointer to a newly allocated string containing a
204 * copy of s or NULL if the string cannot be allocated.
206 char *av_strdup(const char *s) av_malloc_attrib;
209 * Duplicate the buffer p.
210 * @param p buffer to be duplicated
211 * @return Pointer to a newly allocated buffer containing a
212 * copy of p or NULL if the buffer cannot be allocated.
214 void *av_memdup(const void *p, size_t size);
217 * Free a memory block which has been allocated with av_malloc(z)() or
218 * av_realloc() and set the pointer pointing to it to NULL.
219 * @param ptr Pointer to the pointer to the memory block which should
223 void av_freep(void *ptr);
226 * Add an element to a dynamic array.
228 * The array to grow is supposed to be an array of pointers to
229 * structures, and the element to add must be a pointer to an already
230 * allocated structure.
232 * The array is reallocated when its size reaches powers of 2.
233 * Therefore, the amortized cost of adding an element is constant.
235 * In case of success, the pointer to the array is updated in order to
236 * point to the new grown array, and the number pointed to by nb_ptr
238 * In case of failure, the array is freed, *tab_ptr is set to NULL and
239 * *nb_ptr is set to 0.
241 * @param tab_ptr pointer to the array to grow
242 * @param nb_ptr pointer to the number of elements in the array
243 * @param elem element to add
244 * @see av_dynarray2_add()
246 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
249 * Add an element of size elem_size to a dynamic array.
251 * The array is reallocated when its number of elements reaches powers of 2.
252 * Therefore, the amortized cost of adding an element is constant.
254 * In case of success, the pointer to the array is updated in order to
255 * point to the new grown array, and the number pointed to by nb_ptr
257 * In case of failure, the array is freed, *tab_ptr is set to NULL and
258 * *nb_ptr is set to 0.
260 * @param tab_ptr pointer to the array to grow
261 * @param nb_ptr pointer to the number of elements in the array
262 * @param elem_size size in bytes of the elements in the array
263 * @param elem_data pointer to the data of the element to add. If NULL, the space of
264 * the new added element is not filled.
265 * @return pointer to the data of the element to copy in the new allocated space.
266 * If NULL, the new allocated space is left uninitialized."
267 * @see av_dynarray_add()
269 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
270 const uint8_t *elem_data);
273 * Multiply two size_t values checking for overflow.
274 * @return 0 if success, AVERROR(EINVAL) if overflow.
276 static inline int av_size_mult(size_t a, size_t b, size_t *r)
279 /* Hack inspired from glibc: only try the division if nelem and elsize
280 * are both greater than sqrt(SIZE_MAX). */
281 if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
282 return AVERROR(EINVAL);
288 * Set the maximum size that may me allocated in one block.
290 void av_max_alloc(size_t max);
293 * @brief deliberately overlapping memcpy implementation
294 * @param dst destination buffer
295 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
296 * @param cnt number of bytes to copy, must be >= 0
298 * cnt > back is valid, this will copy the bytes we just copied,
299 * thus creating a repeating pattern with a period length of back.
301 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
307 #endif /* AVUTIL_MEM_H */