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 * @note Pointers provided by av_malloc family of functions cannot be
106 * passed to av_realloc().
107 * @param ptr Pointer to a memory block already allocated with
108 * av_realloc() or NULL.
109 * @param size Size in bytes for the memory block to be allocated or
111 * @return Pointer to a newly reallocated block or NULL if the block
112 * cannot be reallocated or the function is used to free the memory block.
113 * @see av_fast_realloc()
115 void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
118 * Allocate or reallocate a block of memory.
119 * This function does the same thing as av_realloc, except:
120 * - It takes two arguments and checks the result of the multiplication for
122 * - It frees the input block in case of failure, thus avoiding the memory
123 * leak with the classic "buf = realloc(buf); if (!buf) return -1;".
125 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
128 * Allocate or reallocate an array.
129 * If ptr is NULL and nmemb > 0, allocate a new block. If
130 * nmemb is zero, free the memory block pointed to by ptr.
131 * @note Pointers provided by av_malloc family of functions cannot be
132 * passed to av_realloc_array().
133 * @param ptr Pointer to a memory block already allocated with
134 * av_realloc() or NULL.
135 * @param nmemb Number of elements
136 * @param size Size of the single element
137 * @return Pointer to a newly reallocated block or NULL if the block
138 * cannot be reallocated or the function is used to free the memory block.
140 av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
143 * Allocate or reallocate an array.
144 * If *ptr is NULL and nmemb > 0, allocate a new block. If
145 * nmemb is zero, free the memory block pointed to by ptr.
146 * @note Pointers provided by av_malloc family of functions cannot be
147 * passed to av_reallocp_array().
148 * @param ptr Pointer to a pointer to a memory block already allocated
149 * with av_realloc(), or pointer to a pointer to NULL.
150 * The pointer is updated on success, or freed on failure.
151 * @param nmemb Number of elements
152 * @param size Size of the single element
153 * @return Zero on success, an AVERROR error code on failure.
155 av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
158 * Free a memory block which has been allocated with av_malloc(z)() or
160 * @param ptr Pointer to the memory block which should be freed.
161 * @note ptr = NULL is explicitly allowed.
162 * @note It is recommended that you use av_freep() instead.
165 void av_free(void *ptr);
168 * Allocate a block of size bytes with alignment suitable for all
169 * memory accesses (including vectors if available on the CPU) and
170 * zero all the bytes of the block.
171 * @param size Size in bytes for the memory block to be allocated.
172 * @return Pointer to the allocated block, NULL if it cannot be allocated.
175 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
178 * Allocate a block of nmemb * size bytes with alignment suitable for all
179 * memory accesses (including vectors if available on the CPU) and
180 * zero all the bytes of the block.
181 * The allocation will fail if nmemb * size is greater than or equal
185 * @return Pointer to the allocated block, NULL if it cannot be allocated.
187 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
190 * Helper function to allocate a block of size * nmemb bytes with
192 * @param nmemb Number of elements
193 * @param size Size of the single element
194 * @return Pointer to the allocated block, NULL if the block cannot
197 * @see av_malloc_array()
199 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
201 if (size <= 0 || nmemb >= INT_MAX / size)
203 return av_mallocz(nmemb * size);
207 * Duplicate the string s.
208 * @param s string to be duplicated
209 * @return Pointer to a newly allocated string containing a
210 * copy of s or NULL if the string cannot be allocated.
212 char *av_strdup(const char *s) av_malloc_attrib;
215 * Duplicate the buffer p.
216 * @param p buffer to be duplicated
217 * @return Pointer to a newly allocated buffer containing a
218 * copy of p or NULL if the buffer cannot be allocated.
220 void *av_memdup(const void *p, size_t size);
223 * Free a memory block which has been allocated with av_malloc(z)() or
224 * av_realloc() and set the pointer pointing to it to NULL.
225 * @param ptr Pointer to the pointer to the memory block which should
229 void av_freep(void *ptr);
232 * Add an element to a dynamic array.
234 * The array to grow is supposed to be an array of pointers to
235 * structures, and the element to add must be a pointer to an already
236 * allocated structure.
238 * The array is reallocated when its size reaches powers of 2.
239 * Therefore, the amortized cost of adding an element is constant.
241 * In case of success, the pointer to the array is updated in order to
242 * point to the new grown array, and the number pointed to by nb_ptr
244 * In case of failure, the array is freed, *tab_ptr is set to NULL and
245 * *nb_ptr is set to 0.
247 * @param tab_ptr pointer to the array to grow
248 * @param nb_ptr pointer to the number of elements in the array
249 * @param elem element to add
250 * @see av_dynarray2_add()
252 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
255 * Add an element of size elem_size to a dynamic array.
257 * The array is reallocated when its number of elements reaches powers of 2.
258 * Therefore, the amortized cost of adding an element is constant.
260 * In case of success, the pointer to the array is updated in order to
261 * point to the new grown array, and the number pointed to by nb_ptr
263 * In case of failure, the array is freed, *tab_ptr is set to NULL and
264 * *nb_ptr is set to 0.
266 * @param tab_ptr pointer to the array to grow
267 * @param nb_ptr pointer to the number of elements in the array
268 * @param elem_size size in bytes of the elements in the array
269 * @param elem_data pointer to the data of the element to add. If NULL, the space of
270 * the new added element is not filled.
271 * @return pointer to the data of the element to copy in the new allocated space.
272 * If NULL, the new allocated space is left uninitialized."
273 * @see av_dynarray_add()
275 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
276 const uint8_t *elem_data);
279 * Multiply two size_t values checking for overflow.
280 * @return 0 if success, AVERROR(EINVAL) if overflow.
282 static inline int av_size_mult(size_t a, size_t b, size_t *r)
285 /* Hack inspired from glibc: only try the division if nelem and elsize
286 * are both greater than sqrt(SIZE_MAX). */
287 if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
288 return AVERROR(EINVAL);
294 * Set the maximum size that may me allocated in one block.
296 void av_max_alloc(size_t max);
299 * @brief deliberately overlapping memcpy implementation
300 * @param dst destination buffer
301 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
302 * @param cnt number of bytes to copy, must be >= 0
304 * cnt > back is valid, this will copy the bytes we just copied,
305 * thus creating a repeating pattern with a period length of back.
307 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
313 #endif /* AVUTIL_MEM_H */