mem.h (5996B)
1 /* 2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> 3 * 4 * This file is part of Libav. 5 * 6 * Libav 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 * Libav 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 Libav; 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 "avutil.h" 34 35 /** 36 * @addtogroup lavu_mem 37 * @{ 38 */ 39 40 41 #if defined(__ICC) && __ICC < 1200 || defined(__SUNPRO_C) 42 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v 43 #define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v 44 #elif defined(__TI_COMPILER_VERSION__) 45 #define DECLARE_ALIGNED(n,t,v) \ 46 AV_PRAGMA(DATA_ALIGN(v,n)) \ 47 t __attribute__((aligned(n))) v 48 #define DECLARE_ASM_CONST(n,t,v) \ 49 AV_PRAGMA(DATA_ALIGN(v,n)) \ 50 static const t __attribute__((aligned(n))) v 51 #elif defined(__GNUC__) 52 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v 53 #define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v 54 #elif defined(_MSC_VER) 55 #define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v 56 #define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v 57 #else 58 #define DECLARE_ALIGNED(n,t,v) t v 59 #define DECLARE_ASM_CONST(n,t,v) static const t v 60 #endif 61 62 #if AV_GCC_VERSION_AT_LEAST(3,1) 63 #define av_malloc_attrib __attribute__((__malloc__)) 64 #else 65 #define av_malloc_attrib 66 #endif 67 68 #if AV_GCC_VERSION_AT_LEAST(4,3) 69 #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__))) 70 #else 71 #define av_alloc_size(...) 72 #endif 73 74 /** 75 * Allocate a block of size bytes with alignment suitable for all 76 * memory accesses (including vectors if available on the CPU). 77 * @param size Size in bytes for the memory block to be allocated. 78 * @return Pointer to the allocated block, NULL if the block cannot 79 * be allocated. 80 * @see av_mallocz() 81 */ 82 void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1); 83 84 /** 85 * Helper function to allocate a block of size * nmemb bytes with 86 * using 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 <= 0 || 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_malloc(z)() or av_realloc() or NULL. 106 * @param size Size in bytes for 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 * @see av_fast_realloc() 111 */ 112 void *av_realloc(void *ptr, size_t size) av_alloc_size(2); 113 114 /** 115 * Free a memory block which has been allocated with av_malloc(z)() or 116 * av_realloc(). 117 * @param ptr Pointer to the memory block which should be freed. 118 * @note ptr = NULL is explicitly allowed. 119 * @note It is recommended that you use av_freep() instead. 120 * @see av_freep() 121 */ 122 void av_free(void *ptr); 123 124 /** 125 * Allocate a block of size bytes with alignment suitable for all 126 * memory accesses (including vectors if available on the CPU) and 127 * zero all the bytes of the block. 128 * @param size Size in bytes for the memory block to be allocated. 129 * @return Pointer to the allocated block, NULL if it cannot be allocated. 130 * @see av_malloc() 131 */ 132 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1); 133 134 /** 135 * Helper function to allocate a block of size * nmemb bytes with 136 * using av_mallocz() 137 * @param nmemb Number of elements 138 * @param size Size of the single element 139 * @return Pointer to the allocated block, NULL if the block cannot 140 * be allocated. 141 * @see av_mallocz() 142 * @see av_malloc_array() 143 */ 144 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size) 145 { 146 if (size <= 0 || nmemb >= INT_MAX / size) 147 return NULL; 148 return av_mallocz(nmemb * size); 149 } 150 151 /** 152 * Duplicate the string s. 153 * @param s string to be duplicated 154 * @return Pointer to a newly allocated string containing a 155 * copy of s or NULL if the string cannot be allocated. 156 */ 157 char *av_strdup(const char *s) av_malloc_attrib; 158 159 /** 160 * Free a memory block which has been allocated with av_malloc(z)() or 161 * av_realloc() and set the pointer pointing to it to NULL. 162 * @param ptr Pointer to the pointer to the memory block which should 163 * be freed. 164 * @see av_free() 165 */ 166 void av_freep(void *ptr); 167 168 /** 169 * @brief deliberately overlapping memcpy implementation 170 * @param dst destination buffer 171 * @param back how many bytes back we start (the initial size of the overlapping window) 172 * @param cnt number of bytes to copy, must be >= 0 173 * 174 * cnt > back is valid, this will copy the bytes we just copied, 175 * thus creating a repeating pattern with a period length of back. 176 */ 177 void av_memcpy_backptr(uint8_t *dst, int back, int cnt); 178 179 /** 180 * @} 181 */ 182 183 #endif /* AVUTIL_MEM_H */