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/*
* MLP codec common code
* Copyright (c) 2007-2008 Ian Caulfield
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "libavutil/crc.h"
#include "libavutil/intreadwrite.h"
#include "mlp.h"
const uint8_t ff_mlp_huffman_tables[3][18][2] = {
{ /* Huffman table 0, -7 - +10 */
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}, { /* Huffman table 1, -7 - +8 */
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x02, 2}, {0x03, 2},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}, { /* Huffman table 2, -7 - +7 */
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x01, 1},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}
};
static int crc_init = 0;
#if CONFIG_SMALL
#define CRC_TABLE_SIZE 257
#else
#define CRC_TABLE_SIZE 1024
#endif
static AVCRC crc_63[CRC_TABLE_SIZE];
static AVCRC crc_1D[CRC_TABLE_SIZE];
static AVCRC crc_2D[CRC_TABLE_SIZE];
av_cold void ff_mlp_init_crc(void)
{
if (!crc_init) {
av_crc_init(crc_63, 0, 8, 0x63, sizeof(crc_63));
av_crc_init(crc_1D, 0, 8, 0x1D, sizeof(crc_1D));
av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
crc_init = 1;
}
}
uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
{
uint16_t crc;
crc = av_crc(crc_2D, 0, buf, buf_size - 2);
crc ^= AV_RL16(buf + buf_size - 2);
return crc;
}
uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
{
uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c
checksum ^= buf[buf_size-1];
return checksum;
}
uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
{
int i;
int num_bytes = (bit_size + 2) / 8;
int crc = crc_1D[buf[0] & 0x3f];
crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2);
crc ^= buf[num_bytes - 1];
for (i = 0; i < ((bit_size + 2) & 7); i++) {
crc <<= 1;
if (crc & 0x100)
crc ^= 0x11D;
crc ^= (buf[num_bytes] >> (7 - i)) & 1;
}
return crc;
}
uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
{
uint32_t scratch = 0;
const uint8_t *buf_end = buf + buf_size;
for (; ((intptr_t) buf & 3) && buf < buf_end; buf++)
scratch ^= *buf;
for (; buf < buf_end - 3; buf += 4)
scratch ^= *((const uint32_t*)buf);
scratch = xor_32_to_8(scratch);
for (; buf < buf_end; buf++)
scratch ^= *buf;
return scratch;
}
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