mem.h 10.5 KB
Newer Older
wester committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307
/*
 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * memory handling functions
 */

#ifndef AVUTIL_MEM_H
#define AVUTIL_MEM_H

#include <limits.h>
#include <stdint.h>

#include "attributes.h"
#include "error.h"
#include "avutil.h"

/**
 * @addtogroup lavu_mem
 * @{
 */


#if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C)
    #define DECLARE_ALIGNED(n,t,v)      t __attribute__ ((aligned (n))) v
    #define DECLARE_ASM_CONST(n,t,v)    const t __attribute__ ((aligned (n))) v
#elif defined(__TI_COMPILER_VERSION__)
    #define DECLARE_ALIGNED(n,t,v)                      \
        AV_PRAGMA(DATA_ALIGN(v,n))                      \
        t __attribute__((aligned(n))) v
    #define DECLARE_ASM_CONST(n,t,v)                    \
        AV_PRAGMA(DATA_ALIGN(v,n))                      \
        static const t __attribute__((aligned(n))) v
#elif defined(__GNUC__)
    #define DECLARE_ALIGNED(n,t,v)      t __attribute__ ((aligned (n))) v
    #define DECLARE_ASM_CONST(n,t,v)    static const t av_used __attribute__ ((aligned (n))) v
#elif defined(_MSC_VER)
    #define DECLARE_ALIGNED(n,t,v)      __declspec(align(n)) t v
    #define DECLARE_ASM_CONST(n,t,v)    __declspec(align(n)) static const t v
#else
    #define DECLARE_ALIGNED(n,t,v)      t v
    #define DECLARE_ASM_CONST(n,t,v)    static const t v
#endif

#if AV_GCC_VERSION_AT_LEAST(3,1)
    #define av_malloc_attrib __attribute__((__malloc__))
#else
    #define av_malloc_attrib
#endif

#if AV_GCC_VERSION_AT_LEAST(4,3)
    #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
#else
    #define av_alloc_size(...)
#endif

/**
 * Allocate a block of size bytes with alignment suitable for all
 * memory accesses (including vectors if available on the CPU).
 * @param size Size in bytes for the memory block to be allocated.
 * @return Pointer to the allocated block, NULL if the block cannot
 * be allocated.
 * @see av_mallocz()
 */
void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);

/**
 * Helper function to allocate a block of size * nmemb bytes with
 * using av_malloc()
 * @param nmemb Number of elements
 * @param size Size of the single element
 * @return Pointer to the allocated block, NULL if the block cannot
 * be allocated.
 * @see av_malloc()
 */
av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
{
    if (size <= 0 || nmemb >= INT_MAX / size)
        return NULL;
    return av_malloc(nmemb * size);
}

/**
 * Allocate or reallocate a block of memory.
 * If ptr is NULL and size > 0, allocate a new block. If
 * size is zero, free the memory block pointed to by ptr.
 * @param ptr Pointer to a memory block already allocated with
 * av_malloc(z)() or av_realloc() or NULL.
 * @param size Size in bytes for the memory block to be allocated or
 * reallocated.
 * @return Pointer to a newly reallocated block or NULL if the block
 * cannot be reallocated or the function is used to free the memory block.
 * @see av_fast_realloc()
 */
void *av_realloc(void *ptr, size_t size) av_alloc_size(2);

/**
 * Allocate or reallocate a block of memory.
 * This function does the same thing as av_realloc, except:
 * - It takes two arguments and checks the result of the multiplication for
 *   integer overflow.
 * - It frees the input block in case of failure, thus avoiding the memory
 *   leak with the classic "buf = realloc(buf); if (!buf) return -1;".
 */
void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);

/**
 * Allocate or reallocate an array.
 * If ptr is NULL and nmemb > 0, allocate a new block. If
 * nmemb is zero, free the memory block pointed to by ptr.
 * @param ptr Pointer to a memory block already allocated with
 * av_malloc(z)() or av_realloc() or NULL.
 * @param nmemb Number of elements
 * @param size Size of the single element
 * @return Pointer to a newly reallocated block or NULL if the block
 * cannot be reallocated or the function is used to free the memory block.
 */
av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);

/**
 * Allocate or reallocate an array.
 * If *ptr is NULL and nmemb > 0, allocate a new block. If
 * nmemb is zero, free the memory block pointed to by ptr.
 * @param ptr Pointer to a pointer to a memory block already allocated
 * with av_malloc(z)() or av_realloc(), or pointer to a pointer to NULL.
 * The pointer is updated on success, or freed on failure.
 * @param nmemb Number of elements
 * @param size Size of the single element
 * @return Zero on success, an AVERROR error code on failure.
 */
av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);

/**
 * Free a memory block which has been allocated with av_malloc(z)() or
 * av_realloc().
 * @param ptr Pointer to the memory block which should be freed.
 * @note ptr = NULL is explicitly allowed.
 * @note It is recommended that you use av_freep() instead.
 * @see av_freep()
 */
void av_free(void *ptr);

/**
 * Allocate a block of size bytes with alignment suitable for all
 * memory accesses (including vectors if available on the CPU) and
 * zero all the bytes of the block.
 * @param size Size in bytes for the memory block to be allocated.
 * @return Pointer to the allocated block, NULL if it cannot be allocated.
 * @see av_malloc()
 */
void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);

/**
 * Allocate a block of nmemb * size bytes with alignment suitable for all
 * memory accesses (including vectors if available on the CPU) and
 * zero all the bytes of the block.
 * The allocation will fail if nmemb * size is greater than or equal
 * to INT_MAX.
 * @param nmemb
 * @param size
 * @return Pointer to the allocated block, NULL if it cannot be allocated.
 */
void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;

/**
 * Helper function to allocate a block of size * nmemb bytes with
 * using av_mallocz()
 * @param nmemb Number of elements
 * @param size Size of the single element
 * @return Pointer to the allocated block, NULL if the block cannot
 * be allocated.
 * @see av_mallocz()
 * @see av_malloc_array()
 */
av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
{
    if (size <= 0 || nmemb >= INT_MAX / size)
        return NULL;
    return av_mallocz(nmemb * size);
}

/**
 * Duplicate the string s.
 * @param s string to be duplicated
 * @return Pointer to a newly allocated string containing a
 * copy of s or NULL if the string cannot be allocated.
 */
char *av_strdup(const char *s) av_malloc_attrib;

/**
 * Duplicate the buffer p.
 * @param p buffer to be duplicated
 * @return Pointer to a newly allocated buffer containing a
 * copy of p or NULL if the buffer cannot be allocated.
 */
void *av_memdup(const void *p, size_t size);

/**
 * Free a memory block which has been allocated with av_malloc(z)() or
 * av_realloc() and set the pointer pointing to it to NULL.
 * @param ptr Pointer to the pointer to the memory block which should
 * be freed.
 * @see av_free()
 */
void av_freep(void *ptr);

/**
 * Add an element to a dynamic array.
 *
 * The array to grow is supposed to be an array of pointers to
 * structures, and the element to add must be a pointer to an already
 * allocated structure.
 *
 * The array is reallocated when its size reaches powers of 2.
 * Therefore, the amortized cost of adding an element is constant.
 *
 * In case of success, the pointer to the array is updated in order to
 * point to the new grown array, and the number pointed to by nb_ptr
 * is incremented.
 * In case of failure, the array is freed, *tab_ptr is set to NULL and
 * *nb_ptr is set to 0.
 *
 * @param tab_ptr pointer to the array to grow
 * @param nb_ptr  pointer to the number of elements in the array
 * @param elem    element to add
 * @see av_dynarray2_add()
 */
void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);

/**
 * Add an element of size elem_size to a dynamic array.
 *
 * The array is reallocated when its number of elements reaches powers of 2.
 * Therefore, the amortized cost of adding an element is constant.
 *
 * In case of success, the pointer to the array is updated in order to
 * point to the new grown array, and the number pointed to by nb_ptr
 * is incremented.
 * In case of failure, the array is freed, *tab_ptr is set to NULL and
 * *nb_ptr is set to 0.
 *
 * @param tab_ptr   pointer to the array to grow
 * @param nb_ptr    pointer to the number of elements in the array
 * @param elem_size size in bytes of the elements in the array
 * @param elem_data pointer to the data of the element to add. If NULL, the space of
 *                  the new added element is not filled.
 * @return          pointer to the data of the element to copy in the new allocated space.
 *                  If NULL, the new allocated space is left uninitialized."
 * @see av_dynarray_add()
 */
void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
                       const uint8_t *elem_data);

/**
 * Multiply two size_t values checking for overflow.
 * @return  0 if success, AVERROR(EINVAL) if overflow.
 */
static inline int av_size_mult(size_t a, size_t b, size_t *r)
{
    size_t t = a * b;
    /* Hack inspired from glibc: only try the division if nelem and elsize
     * are both greater than sqrt(SIZE_MAX). */
    if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
        return AVERROR(EINVAL);
    *r = t;
    return 0;
}

/**
 * Set the maximum size that may me allocated in one block.
 */
void av_max_alloc(size_t max);

/**
 * @brief deliberately overlapping memcpy implementation
 * @param dst destination buffer
 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
 * @param cnt number of bytes to copy, must be >= 0
 *
 * cnt > back is valid, this will copy the bytes we just copied,
 * thus creating a repeating pattern with a period length of back.
 */
void av_memcpy_backptr(uint8_t *dst, int back, int cnt);

/**
 * @}
 */

#endif /* AVUTIL_MEM_H */