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 * Free a memory block which has been allocated with av_malloc(z)() or
128 * @param ptr Pointer to the memory block which should be freed.
129 * @note ptr = NULL is explicitly allowed.
130 * @note It is recommended that you use av_freep() instead.
133 void av_free(void *ptr);
136 * Allocate a block of size bytes with alignment suitable for all
137 * memory accesses (including vectors if available on the CPU) and
138 * zero all the bytes of the block.
139 * @param size Size in bytes for the memory block to be allocated.
140 * @return Pointer to the allocated block, NULL if it cannot be allocated.
143 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
146 * Allocate a block of nmemb * size bytes with alignment suitable for all
147 * memory accesses (including vectors if available on the CPU) and
148 * zero all the bytes of the block.
149 * The allocation will fail if nmemb * size is greater than or equal
153 * @return Pointer to the allocated block, NULL if it cannot be allocated.
155 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
158 * Helper function to allocate a block of size * nmemb bytes with
160 * @param nmemb Number of elements
161 * @param size Size of the single element
162 * @return Pointer to the allocated block, NULL if the block cannot
165 * @see av_malloc_array()
167 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
169 if (size <= 0 || nmemb >= INT_MAX / size)
171 return av_mallocz(nmemb * size);
175 * Duplicate the string s.
176 * @param s string to be duplicated
177 * @return Pointer to a newly allocated string containing a
178 * copy of s or NULL if the string cannot be allocated.
180 char *av_strdup(const char *s) av_malloc_attrib;
183 * Free a memory block which has been allocated with av_malloc(z)() or
184 * av_realloc() and set the pointer pointing to it to NULL.
185 * @param ptr Pointer to the pointer to the memory block which should
189 void av_freep(void *ptr);
192 * Add an element to a dynamic array.
194 * @param tab_ptr Pointer to the array.
195 * @param nb_ptr Pointer to the number of elements in the array.
196 * @param elem Element to be added.
198 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
201 * Multiply two size_t values checking for overflow.
202 * @return 0 if success, AVERROR(EINVAL) if overflow.
204 static inline int av_size_mult(size_t a, size_t b, size_t *r)
207 /* Hack inspired from glibc: only try the division if nelem and elsize
208 * are both greater than sqrt(SIZE_MAX). */
209 if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
210 return AVERROR(EINVAL);
216 * Set the maximum size that may me allocated in one block.
218 void av_max_alloc(size_t max);
221 * @brief deliberately overlapping memcpy implementation
222 * @param dst destination buffer
223 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
224 * @param cnt number of bytes to copy, must be >= 0
226 * cnt > back is valid, this will copy the bytes we just copied,
227 * thus creating a repeating pattern with a period length of back.
229 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
235 #endif /* AVUTIL_MEM_H */