lavu: add AV_DYNARRAY_ADD() macro.

Signed-off-by: Nicolas George <george@nsup.org>
Reviewed-by: Lukasz Marek <lukasz.m.luki@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Nicolas George 2014-03-08 21:26:59 +01:00 committed by Michael Niedermayer
parent cd1d4b51e3
commit 7b9a310d0e
1 changed files with 72 additions and 0 deletions

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libavutil/dynarray.h Normal file
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/*
* 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
*/
#ifndef AVUTIL_DYNARRAY_H
#define AVUTIL_DYNARRAY_H
#include "log.h"
#include "mem.h"
/**
* Add an element of 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 size is incremented.
*
* @param av_size_max maximum size of the array, usually the MAX macro of
* the type of the size
* @param av_elt_size size of the elements in the array, in bytes
* @param av_array pointer to the array, must be a lvalue
* @param av_size size of the array, must be an interger lvalue
* @param av_success statement to execute on success; at this point, the
* size variable is not yet incremented
* @param av_failure statement to execute on failure; if this happens, the
* array and size are not changed; the statement can end
* with a return or a goto
*/
#define AV_DYNARRAY_ADD(av_size_max, av_elt_size, av_array, av_size, \
av_success, av_failure) \
do { \
size_t av_size_new = (av_size); \
if (!((av_size) & ((av_size) - 1))) { \
av_size_new = (av_size) ? (av_size) << 1 : 1; \
if (av_size_new > (av_size_max) / (av_elt_size)) { \
av_size_new = 0; \
} else { \
void *av_array_new = \
av_realloc((av_array), av_size_new * (av_elt_size)); \
av_log(NULL, AV_LOG_DEBUG, "Resizing array to %zd\n", \
av_size_new); \
if (!av_array_new) \
av_size_new = 0; \
else \
(av_array) = av_array_new; \
} \
} \
if (av_size_new) { \
{ av_success } \
(av_size)++; \
} else { \
av_failure \
} \
} while (0)
#endif /* AVUTIL_DYNARRAY_H */