blob: d34981e67d262880b064aa9909c04c0e6864a79d (
plain)
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
|
/*
* Copyright (c) 2003-2010 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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;
}
|
