FFmpeg
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pngdsp.c
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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/attributes.h"
23 #include "libavutil/common.h"
24 #include "png.h"
25 #include "pngdsp.h"
26 
27 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
28 #define pb_7f (~0UL / 255 * 0x7f)
29 #define pb_80 (~0UL / 255 * 0x80)
30 
31 static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
32 {
33  long i;
34  for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {
35  long a = *(long *)(src1 + i);
36  long b = *(long *)(src2 + i);
37  *(long *)(dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);
38  }
39  for (; i < w; i++)
40  dst[i] = src1[i] + src2[i];
41 }
42 
44 {
47 
48  if (ARCH_X86)
49  ff_pngdsp_init_x86(dsp);
50 }
#define pb_80
Definition: pngdsp.c:29
void(* add_bytes_l2)(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
Definition: pngdsp.h:28
const char * b
Definition: vf_curves.c:113
Macro definitions for various function/variable attributes.
uint8_t
#define av_cold
Definition: attributes.h:82
static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
Definition: pngdsp.c:31
void(* add_paeth_prediction)(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
Definition: pngdsp.h:33
#define pb_7f
Definition: pngdsp.c:28
av_cold void ff_pngdsp_init(PNGDSPContext *dsp)
Definition: pngdsp.c:43
#define src1
Definition: h264pred.c:139
void ff_pngdsp_init_x86(PNGDSPContext *dsp)
Definition: pngdsp_init.c:36
int
common internal and external API header
void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
Definition: pngdec.c:173