mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
270cede3f3
This permits re-use with parsers for codecs which use similar start codes. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
/*
|
|
* Copyright (c) 2003-2010 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
|
|
* Accelerated start code search function for start codes common to
|
|
* MPEG-1/2/4 video, VC-1, H.264/5
|
|
* @author Michael Niedermayer <michaelni@gmx.at>
|
|
*/
|
|
|
|
#include "startcode.h"
|
|
#include "config.h"
|
|
|
|
int ff_startcode_find_candidate_c(const uint8_t *buf, int size)
|
|
{
|
|
int i = 0;
|
|
#if HAVE_FAST_UNALIGNED
|
|
/* we check i < size instead of i + 3 / 7 because it is
|
|
* simpler and there must be FF_INPUT_BUFFER_PADDING_SIZE
|
|
* bytes at the end.
|
|
*/
|
|
# if HAVE_FAST_64BIT
|
|
while (i < size &&
|
|
!((~*(const uint64_t *)(buf + i) &
|
|
(*(const uint64_t *)(buf + i) - 0x0101010101010101ULL)) &
|
|
0x8080808080808080ULL))
|
|
i += 8;
|
|
# else
|
|
while (i < size &&
|
|
!((~*(const uint32_t *)(buf + i) &
|
|
(*(const uint32_t *)(buf + i) - 0x01010101U)) &
|
|
0x80808080U))
|
|
i += 4;
|
|
# endif
|
|
#endif
|
|
for (; i < size; i++)
|
|
if (!buf[i])
|
|
break;
|
|
return i;
|
|
}
|