Line data Source code
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 6037 : static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
32 : {
33 : long i;
34 486361 : for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {
35 480324 : long a = *(long *)(src1 + i);
36 480324 : long b = *(long *)(src2 + i);
37 480324 : *(long *)(dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);
38 : }
39 17563 : for (; i < w; i++)
40 11526 : dst[i] = src1[i] + src2[i];
41 6037 : }
42 :
43 100 : av_cold void ff_pngdsp_init(PNGDSPContext *dsp)
44 : {
45 100 : dsp->add_bytes_l2 = add_bytes_l2_c;
46 100 : dsp->add_paeth_prediction = ff_add_png_paeth_prediction;
47 :
48 : if (ARCH_X86)
49 100 : ff_pngdsp_init_x86(dsp);
50 100 : }
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