/* * PNG image format * Copyright (c) 2008 Loren Merrit <lorenm@u.washington.edu> * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/attributes.h" #include "libavutil/common.h" #include "png.h" #include "pngdsp.h" // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size #define pb_7f (~0UL / 255 * 0x7f) #define pb_80 (~0UL / 255 * 0x80) static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w) { long i; for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) { long a = *(long *)(src1 + i); long b = *(long *)(src2 + i); *(long *)(dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80); } for (; i < w; i++) dst[i] = src1[i] + src2[i]; } av_cold void ff_pngdsp_init(PNGDSPContext *dsp) { dsp->add_bytes_l2 = add_bytes_l2_c; dsp->add_paeth_prediction = ff_add_png_paeth_prediction; if (ARCH_X86) ff_pngdsp_init_x86(dsp); }