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https://github.com/xenia-project/FFmpeg.git
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37e81996dc
* commit '9221efef7968463f3e3d9ce79ea72eaca082e73f': lavf: fix av_interleaved_write_frame() doxy. lavf: clarify the lifetime of demuxed packets. avconv: do not free muxed packet on streamcopy. crc: move doxy to the header vf_drawtext: do not use deprecated av_tree_node_size x86: Refactor PSWAPD fallback implementations and port to cpuflags Merged-by: Michael Niedermayer <michaelni@gmx.at>
138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
/*
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* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "config.h"
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#include "common.h"
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#include "bswap.h"
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#include "crc.h"
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#if CONFIG_HARDCODED_TABLES
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#include "crc_data.h"
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#else
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static struct {
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uint8_t le;
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uint8_t bits;
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uint32_t poly;
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} av_crc_table_params[AV_CRC_MAX] = {
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[AV_CRC_8_ATM] = { 0, 8, 0x07 },
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[AV_CRC_16_ANSI] = { 0, 16, 0x8005 },
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[AV_CRC_16_CCITT] = { 0, 16, 0x1021 },
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[AV_CRC_32_IEEE] = { 0, 32, 0x04C11DB7 },
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[AV_CRC_32_IEEE_LE] = { 1, 32, 0xEDB88320 },
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};
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static AVCRC av_crc_table[AV_CRC_MAX][257];
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#endif
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int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size)
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{
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unsigned i, j;
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uint32_t c;
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if (bits < 8 || bits > 32 || poly >= (1LL << bits))
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return -1;
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if (ctx_size != sizeof(AVCRC) * 257 && ctx_size != sizeof(AVCRC) * 1024)
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return -1;
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for (i = 0; i < 256; i++) {
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if (le) {
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for (c = i, j = 0; j < 8; j++)
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c = (c >> 1) ^ (poly & (-(c & 1)));
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ctx[i] = c;
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} else {
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for (c = i << 24, j = 0; j < 8; j++)
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c = (c << 1) ^ ((poly << (32 - bits)) & (((int32_t) c) >> 31));
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ctx[i] = av_bswap32(c);
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}
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}
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ctx[256] = 1;
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#if !CONFIG_SMALL
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if (ctx_size >= sizeof(AVCRC) * 1024)
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for (i = 0; i < 256; i++)
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for (j = 0; j < 3; j++)
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ctx[256 *(j + 1) + i] =
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(ctx[256 * j + i] >> 8) ^ ctx[ctx[256 * j + i] & 0xFF];
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#endif
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return 0;
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}
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const AVCRC *av_crc_get_table(AVCRCId crc_id)
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{
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#if !CONFIG_HARDCODED_TABLES
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if (!av_crc_table[crc_id][FF_ARRAY_ELEMS(av_crc_table[crc_id]) - 1])
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if (av_crc_init(av_crc_table[crc_id],
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av_crc_table_params[crc_id].le,
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av_crc_table_params[crc_id].bits,
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av_crc_table_params[crc_id].poly,
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sizeof(av_crc_table[crc_id])) < 0)
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return NULL;
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#endif
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return av_crc_table[crc_id];
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}
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uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
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const uint8_t *buffer, size_t length)
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{
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const uint8_t *end = buffer + length;
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#if !CONFIG_SMALL
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if (!ctx[256]) {
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while (((intptr_t) buffer & 3) && buffer < end)
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crc = ctx[((uint8_t) crc) ^ *buffer++] ^ (crc >> 8);
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while (buffer < end - 3) {
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crc ^= av_le2ne32(*(const uint32_t *) buffer); buffer += 4;
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crc = ctx[3 * 256 + ( crc & 0xFF)] ^
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ctx[2 * 256 + ((crc >> 8 ) & 0xFF)] ^
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ctx[1 * 256 + ((crc >> 16) & 0xFF)] ^
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ctx[0 * 256 + ((crc >> 24) )];
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}
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}
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#endif
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while (buffer < end)
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crc = ctx[((uint8_t) crc) ^ *buffer++] ^ (crc >> 8);
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return crc;
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}
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#ifdef TEST
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#undef printf
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int main(void)
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{
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uint8_t buf[1999];
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int i;
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int p[4][3] = { { AV_CRC_32_IEEE_LE, 0xEDB88320, 0x3D5CDD04 },
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{ AV_CRC_32_IEEE , 0x04C11DB7, 0xC0F5BAE0 },
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{ AV_CRC_16_ANSI , 0x8005 , 0x1FBB },
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{ AV_CRC_8_ATM , 0x07 , 0xE3 }
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};
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const AVCRC *ctx;
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for (i = 0; i < sizeof(buf); i++)
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buf[i] = i + i * i;
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for (i = 0; i < 4; i++) {
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ctx = av_crc_get_table(p[i][0]);
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printf("crc %08X = %X\n", p[i][1], av_crc(ctx, 0, buf, sizeof(buf)));
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}
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return 0;
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}
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#endif
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