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()
+ * Allocate a block of size * nmemb bytes with 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
*/
av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
{
- if (size <= 0 || nmemb >= INT_MAX / size)
+ if (!size || 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.
- * @note Pointers provided by av_malloc family of functions cannot be
- * passed to av_realloc().
* @param ptr Pointer to a memory block already allocated with
* av_realloc() or NULL.
- * @param size Size in bytes for the memory block to be allocated or
+ * @param size Size in bytes of the memory block to be allocated or
* reallocated.
- * @return Pointer to a newly reallocated block or NULL if the block
+ * @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.
+ * @warning Pointers originating from the av_malloc() family of functions must
+ * not be passed to av_realloc(). The former can be implemented using
+ * memalign() (or other functions), and there is no guarantee that
+ * pointers from such functions can be passed to realloc() at all.
+ * The situation is undefined according to POSIX and may crash with
+ * some libc implementations.
* @see av_fast_realloc()
*/
void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
+/**
+ * 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 pointer to a memory block already allocated
+ * with av_realloc(), or pointer to a pointer to NULL.
+ * The pointer is updated on success, or freed on failure.
+ * @param size Size in bytes for the memory block to be allocated or
+ * reallocated
+ * @return Zero on success, an AVERROR error code on failure.
+ * @warning Pointers originating from the av_malloc() family of functions must
+ * not be passed to av_reallocp(). The former can be implemented using
+ * memalign() (or other functions), and there is no guarantee that
+ * pointers from such functions can be passed to realloc() at all.
+ * The situation is undefined according to POSIX and may crash with
+ * some libc implementations.
+ */
+int av_reallocp(void *ptr, 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.
- * @note Pointers provided by av_malloc family of functions cannot be
- * passed to av_realloc_array().
* @param ptr Pointer to a memory block already allocated with
* 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
+ * @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.
+ * @warning Pointers originating from the av_malloc() family of functions must
+ * not be passed to av_realloc(). The former can be implemented using
+ * memalign() (or other functions), and there is no guarantee that
+ * pointers from such functions can be passed to realloc() at all.
+ * The situation is undefined according to POSIX and may crash with
+ * some libc implementations.
*/
av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
/**
- * Allocate or reallocate an array.
+ * Allocate or reallocate an array through a pointer to a pointer.
* If *ptr is NULL and nmemb > 0, allocate a new block. If
* nmemb is zero, free the memory block pointed to by ptr.
- * @note Pointers provided by av_malloc family of functions cannot be
- * passed to av_reallocp_array().
* @param ptr Pointer to a pointer to a memory block already allocated
* with 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.
+ * @warning Pointers originating from the av_malloc() family of functions must
+ * not be passed to av_realloc(). The former can be implemented using
+ * memalign() (or other functions), and there is no guarantee that
+ * pointers from such functions can be passed to realloc() at all.
+ * The situation is undefined according to POSIX and may crash with
+ * some libc implementations.
*/
av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
/**
- * Helper function to allocate a block of size * nmemb bytes with
- * using av_mallocz()
+ * Allocate a block of size * nmemb bytes with 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
*/
av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
{
- if (size <= 0 || nmemb >= INT_MAX / size)
+ if (!size || 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
+ * @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 a substring of the string s.
+ * @param s string to be duplicated
+ * @param len the maximum length of the resulting string (not counting the
+ * terminating byte).
+ * @return Pointer to a newly-allocated string containing a
+ * copy of s or NULL if the string cannot be allocated.
+ */
+char *av_strndup(const char *s, size_t len) av_malloc_attrib;
+
/**
* Free a memory block which has been allocated with av_malloc(z)() or
* av_realloc() and set the pointer pointing to it to NULL.
void av_freep(void *ptr);
/**
- * @brief deliberately overlapping memcpy implementation
+ * deliberately overlapping memcpy implementation
* @param dst destination buffer
* @param back how many bytes back we start (the initial size of the overlapping window)
* @param cnt number of bytes to copy, must be >= 0
*/
void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
+/**
+ * Reallocate the given block if it is not large enough, otherwise do nothing.
+ *
+ * @see av_realloc
+ */
+void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
+
+/**
+ * Allocate a buffer, reusing the given one if large enough.
+ *
+ * Contrary to av_fast_realloc the current buffer contents might not be
+ * preserved and on error the old buffer is freed, thus no special
+ * handling to avoid memleaks is necessary.
+ *
+ * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
+ * @param size size of the buffer *ptr points to
+ * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
+ * *size 0 if an error occurred.
+ */
+void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
+
/**
* @}
*/
projects / ffmpeg / blobdiff