2134
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1 /*
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2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
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3 *
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4 * This file is part of FFmpeg.
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5 *
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6 * FFmpeg is free software; you can redistribute it and/or
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7 * modify it under the terms of the GNU Lesser General Public
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8 * License as published by the Free Software Foundation; either
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9 * version 2.1 of the License, or (at your option) any later version.
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10 *
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11 * FFmpeg is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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14 * Lesser General Public License for more details.
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15 *
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16 * You should have received a copy of the GNU Lesser General Public
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17 * License along with FFmpeg; if not, write to the Free Software
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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19 */
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20
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21 /**
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22 * @file
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23 * memory handling functions
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24 */
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25
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26 #ifndef AVUTIL_MEM_H
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27 #define AVUTIL_MEM_H
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28
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29 #include <limits.h>
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30 #include <stdint.h>
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31
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32 #include "attributes.h"
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33 #include "error.h"
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34 #include "avutil.h"
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35
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36 /**
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37 * @addtogroup lavu_mem
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38 * @{
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39 */
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40
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41
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42 #if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C)
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43 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
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44 #define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v
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45 #elif defined(__TI_COMPILER_VERSION__)
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46 #define DECLARE_ALIGNED(n,t,v) \
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47 AV_PRAGMA(DATA_ALIGN(v,n)) \
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48 t __attribute__((aligned(n))) v
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49 #define DECLARE_ASM_CONST(n,t,v) \
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50 AV_PRAGMA(DATA_ALIGN(v,n)) \
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51 static const t __attribute__((aligned(n))) v
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52 #elif defined(__GNUC__)
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53 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
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54 #define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v
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55 #elif defined(_MSC_VER)
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56 #define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v
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57 #define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v
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58 #else
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59 #define DECLARE_ALIGNED(n,t,v) t v
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60 #define DECLARE_ASM_CONST(n,t,v) static const t v
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61 #endif
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62
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63 #if AV_GCC_VERSION_AT_LEAST(3,1)
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64 #define av_malloc_attrib __attribute__((__malloc__))
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65 #else
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66 #define av_malloc_attrib
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67 #endif
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68
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69 #if AV_GCC_VERSION_AT_LEAST(4,3)
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70 #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
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71 #else
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72 #define av_alloc_size(...)
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73 #endif
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74
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75 /**
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76 * Allocate a block of size bytes with alignment suitable for all
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77 * memory accesses (including vectors if available on the CPU).
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78 * @param size Size in bytes for the memory block to be allocated.
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79 * @return Pointer to the allocated block, NULL if the block cannot
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80 * be allocated.
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81 * @see av_mallocz()
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82 */
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83 void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);
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84
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85 /**
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86 * Helper function to allocate a block of size * nmemb bytes with
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87 * using av_malloc()
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88 * @param nmemb Number of elements
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89 * @param size Size of the single element
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90 * @return Pointer to the allocated block, NULL if the block cannot
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91 * be allocated.
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92 * @see av_malloc()
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93 */
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94 av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
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95 {
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96 if (size <= 0 || nmemb >= INT_MAX / size)
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97 return NULL;
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98 return av_malloc(nmemb * size);
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99 }
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100
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101 /**
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102 * Allocate or reallocate a block of memory.
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103 * If ptr is NULL and size > 0, allocate a new block. If
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104 * size is zero, free the memory block pointed to by ptr.
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105 * @param ptr Pointer to a memory block already allocated with
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106 * av_malloc(z)() or av_realloc() or NULL.
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107 * @param size Size in bytes for the memory block to be allocated or
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108 * reallocated.
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109 * @return Pointer to a newly reallocated block or NULL if the block
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110 * cannot be reallocated or the function is used to free the memory block.
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111 * @see av_fast_realloc()
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112 */
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113 void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
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114
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115 /**
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116 * Allocate or reallocate a block of memory.
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117 * This function does the same thing as av_realloc, except:
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118 * - It takes two arguments and checks the result of the multiplication for
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119 * integer overflow.
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120 * - It frees the input block in case of failure, thus avoiding the memory
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121 * leak with the classic "buf = realloc(buf); if (!buf) return -1;".
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122 */
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123 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
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124
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125 /**
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126 * Free a memory block which has been allocated with av_malloc(z)() or
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127 * av_realloc().
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128 * @param ptr Pointer to the memory block which should be freed.
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129 * @note ptr = NULL is explicitly allowed.
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130 * @note It is recommended that you use av_freep() instead.
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131 * @see av_freep()
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132 */
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133 void av_free(void *ptr);
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134
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135 /**
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136 * Allocate a block of size bytes with alignment suitable for all
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137 * memory accesses (including vectors if available on the CPU) and
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138 * zero all the bytes of the block.
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139 * @param size Size in bytes for the memory block to be allocated.
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140 * @return Pointer to the allocated block, NULL if it cannot be allocated.
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141 * @see av_malloc()
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142 */
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143 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
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144
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145 /**
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146 * Allocate a block of nmemb * size bytes with alignment suitable for all
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147 * memory accesses (including vectors if available on the CPU) and
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148 * zero all the bytes of the block.
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149 * The allocation will fail if nmemb * size is greater than or equal
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150 * to INT_MAX.
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151 * @param nmemb
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152 * @param size
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153 * @return Pointer to the allocated block, NULL if it cannot be allocated.
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154 */
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155 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
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156
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157 /**
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158 * Helper function to allocate a block of size * nmemb bytes with
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159 * using av_mallocz()
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160 * @param nmemb Number of elements
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161 * @param size Size of the single element
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162 * @return Pointer to the allocated block, NULL if the block cannot
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163 * be allocated.
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164 * @see av_mallocz()
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165 * @see av_malloc_array()
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166 */
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167 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
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168 {
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169 if (size <= 0 || nmemb >= INT_MAX / size)
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170 return NULL;
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171 return av_mallocz(nmemb * size);
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172 }
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173
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174 /**
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175 * Duplicate the string s.
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176 * @param s string to be duplicated
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177 * @return Pointer to a newly allocated string containing a
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178 * copy of s or NULL if the string cannot be allocated.
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179 */
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180 char *av_strdup(const char *s) av_malloc_attrib;
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181
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182 /**
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183 * Duplicate the buffer p.
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184 * @param p buffer to be duplicated
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185 * @return Pointer to a newly allocated buffer containing a
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186 * copy of p or NULL if the buffer cannot be allocated.
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187 */
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188 void *av_memdup(const void *p, size_t size);
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189
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190 /**
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191 * Free a memory block which has been allocated with av_malloc(z)() or
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192 * av_realloc() and set the pointer pointing to it to NULL.
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193 * @param ptr Pointer to the pointer to the memory block which should
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194 * be freed.
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195 * @see av_free()
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196 */
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197 void av_freep(void *ptr);
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198
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199 /**
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200 * Add an element to a dynamic array.
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201 *
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202 * The array to grow is supposed to be an array of pointers to
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203 * structures, and the element to add must be a pointer to an already
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204 * allocated structure.
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205 *
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206 * The array is reallocated when its size reaches powers of 2.
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207 * Therefore, the amortized cost of adding an element is constant.
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208 *
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209 * In case of success, the pointer to the array is updated in order to
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210 * point to the new grown array, and the number pointed to by nb_ptr
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211 * is incremented.
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212 * In case of failure, the array is freed, *tab_ptr is set to NULL and
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213 * *nb_ptr is set to 0.
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214 *
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215 * @param tab_ptr pointer to the array to grow
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216 * @param nb_ptr pointer to the number of elements in the array
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217 * @param elem element to add
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218 * @see av_dynarray2_add()
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219 */
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220 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
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221
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222 /**
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223 * Add an element of size elem_size to a dynamic array.
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224 *
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225 * The array is reallocated when its number of elements reaches powers of 2.
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226 * Therefore, the amortized cost of adding an element is constant.
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227 *
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228 * In case of success, the pointer to the array is updated in order to
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229 * point to the new grown array, and the number pointed to by nb_ptr
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230 * is incremented.
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231 * In case of failure, the array is freed, *tab_ptr is set to NULL and
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232 * *nb_ptr is set to 0.
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233 *
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234 * @param tab_ptr pointer to the array to grow
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235 * @param nb_ptr pointer to the number of elements in the array
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236 * @param elem_size size in bytes of the elements in the array
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237 * @param elem_data pointer to the data of the element to add. If NULL, the space of
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238 * the new added element is not filled.
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239 * @return pointer to the data of the element to copy in the new allocated space.
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240 * If NULL, the new allocated space is left uninitialized."
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241 * @see av_dynarray_add()
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242 */
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243 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
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244 const uint8_t *elem_data);
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245
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246 /**
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247 * Multiply two size_t values checking for overflow.
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248 * @return 0 if success, AVERROR(EINVAL) if overflow.
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249 */
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250 static inline int av_size_mult(size_t a, size_t b, size_t *r)
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251 {
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252 size_t t = a * b;
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253 /* Hack inspired from glibc: only try the division if nelem and elsize
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254 * are both greater than sqrt(SIZE_MAX). */
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255 if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
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256 return AVERROR(EINVAL);
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257 *r = t;
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258 return 0;
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259 }
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260
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261 /**
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262 * Set the maximum size that may me allocated in one block.
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263 */
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264 void av_max_alloc(size_t max);
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265
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266 /**
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267 * @brief deliberately overlapping memcpy implementation
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268 * @param dst destination buffer
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269 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
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270 * @param cnt number of bytes to copy, must be >= 0
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271 *
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272 * cnt > back is valid, this will copy the bytes we just copied,
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273 * thus creating a repeating pattern with a period length of back.
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274 */
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275 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
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276
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277 /**
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278 * @}
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279 */
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280
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281 #endif /* AVUTIL_MEM_H */
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