FFmpeg
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 "config.h"
23 #include "libavutil/attributes.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/macros.h"
26 #include "png.h"
27 #include "pngdsp.h"
28 
29 #if HAVE_FAST_64BIT
30 #define BITS 64
31 typedef uint64_t uint_native;
32 #else
33 #define BITS 32
34 typedef uint32_t uint_native;
35 #endif
36 #define RN AV_JOIN(AV_RN, BITS)
37 #define RNA AV_JOIN(AV_JOIN(AV_RN, BITS), A)
38 #define WN AV_JOIN(AV_WN, BITS)
39 
40 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
41 #define pb_7f (~(uint_native)0 / 255 * 0x7f)
42 #define pb_80 (~(uint_native)0 / 255 * 0x80)
43 
44 static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
45 {
46  long i;
47  for (i = 0; i <= w - (int) sizeof(uint_native); i += sizeof(uint_native)) {
48  uint_native a = RNA(src1 + i);
49  uint_native b = RN (src2 + i);
50  WN(dst + i, ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80));
51  }
52  for (; i < w; i++)
53  dst[i] = src1[i] + src2[i];
54 }
55 
57 {
60 
61 #if ARCH_X86
62  ff_pngdsp_init_x86(dsp);
63 #endif
64 }
PNGDSPContext
Definition: pngdsp.h:27
pb_80
#define pb_80
Definition: pngdsp.c:42
RNA
#define RNA
Definition: pngdsp.c:37
PNGDSPContext::add_paeth_prediction
void(* add_paeth_prediction)(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
Definition: pngdsp.h:33
src1
const pixel * src1
Definition: h264pred_template.c:421
RN
#define RN
Definition: pngdsp.c:36
w
uint8_t w
Definition: llviddspenc.c:38
ff_pngdsp_init_x86
void ff_pngdsp_init_x86(PNGDSPContext *dsp)
Definition: pngdsp_init.c:34
b
#define b
Definition: input.c:41
add_bytes_l2_c
static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
Definition: pngdsp.c:44
pb_7f
#define pb_7f
Definition: pngdsp.c:41
macros.h
pngdsp.h
av_cold
#define av_cold
Definition: attributes.h:90
WN
#define WN
Definition: pngdsp.c:38
intreadwrite.h
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
attributes.h
ff_pngdsp_init
av_cold void ff_pngdsp_init(PNGDSPContext *dsp)
Definition: pngdsp.c:56
PNGDSPContext::add_bytes_l2
void(* add_bytes_l2)(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
Definition: pngdsp.h:28
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
src2
const pixel * src2
Definition: h264pred_template.c:422
uint_native
uint32_t uint_native
Definition: pngdsp.c:34
ff_add_png_paeth_prediction
void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
Definition: pngdec.c:218
png.h
int
int
Definition: ffmpeg_filter.c:424
uint_native
uint32_t uint_native
Definition: huffyuvencdsp.c:30