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 31static 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 43av_cold void ff_pngdsp_init(PNGDSPContext *dsp) 44{ 45 dsp->add_bytes_l2 = add_bytes_l2_c; 46 dsp->add_paeth_prediction = ff_add_png_paeth_prediction; 47 48 if (ARCH_X86) 49 ff_pngdsp_init_x86(dsp); 50} 51