FFmpeg
Main Page
Related Pages
Modules
Data Structures
Files
Examples
File List
Globals
All
Data Structures
Files
Functions
Variables
Typedefs
Enumerations
Enumerator
Macros
Groups
Pages
libavcodec
pngdsp.c
Go to the documentation of this file.
1
/*
2
* PNG image format
3
* Copyright (c) 2008 Loren Merrit <lorenm@u.washington.edu>
4
*
5
* This file is part of FFmpeg.
6
*
7
* FFmpeg is free software; you can redistribute it and/or
8
* modify it under the terms of the GNU Lesser General Public
9
* License as published by the Free Software Foundation; either
10
* version 2.1 of the License, or (at your option) any later version.
11
*
12
* FFmpeg is distributed in the hope that it will be useful,
13
* but WITHOUT ANY WARRANTY; without even the implied warranty of
14
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15
* Lesser General Public License for more details.
16
*
17
* You should have received a copy of the GNU Lesser General Public
18
* License along with FFmpeg; if not, write to the Free Software
19
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
*/
21
22
#include "
libavutil/common.h
"
23
#include "
png.h
"
24
#include "
pngdsp.h
"
25
26
// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
27
#define pb_7f (~0UL/255 * 0x7f)
28
#define pb_80 (~0UL/255 * 0x80)
29
30
static
void
add_bytes_l2_c
(
uint8_t
*
dst
,
uint8_t
*src1,
uint8_t
*src2,
int
w)
31
{
32
long
i;
33
for
(i = 0; i <= w -
sizeof
(long); i +=
sizeof
(long)) {
34
long
a
= *(
long
*)(src1 + i);
35
long
b
= *(
long
*)(src2 + i);
36
*(
long
*)(dst + i) = ((a &
pb_7f
) + (b &
pb_7f
)) ^ ((a ^ b) &
pb_80
);
37
}
38
for
(; i < w; i++)
39
dst[i] = src1[i] + src2[i];
40
}
41
42
void
ff_pngdsp_init
(
PNGDSPContext
*dsp)
43
{
44
dsp->
add_bytes_l2
=
add_bytes_l2_c
;
45
dsp->
add_paeth_prediction
=
ff_add_png_paeth_prediction
;
46
47
if
(ARCH_X86)
ff_pngdsp_init_x86
(dsp);
48
}
Generated on Sat May 25 2013 04:01:09 for FFmpeg by
1.8.2