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/*
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 * MLP codec common code
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 * Copyright (c) 2007-2008 Ian Caulfield
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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 <stdint.h>
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#include "libavutil/crc.h"
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#include "libavutil/intreadwrite.h"
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#include "mlp.h"
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const uint8_t ff_mlp_huffman_tables[3][18][2] = {
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    {    /* Huffman table 0, -7 - +10 */
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        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
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        {0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
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        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
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    }, { /* Huffman table 1, -7 - +8 */
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        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
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        {0x02, 2}, {0x03, 2},
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        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
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    }, { /* Huffman table 2, -7 - +7 */
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        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
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        {0x01, 1},
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        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
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    }
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};
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static int crc_init = 0;
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#if CONFIG_SMALL
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#define CRC_TABLE_SIZE 257
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#else
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#define CRC_TABLE_SIZE 1024
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#endif
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static AVCRC crc_63[CRC_TABLE_SIZE];
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static AVCRC crc_1D[CRC_TABLE_SIZE];
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static AVCRC crc_2D[CRC_TABLE_SIZE];
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av_cold void ff_mlp_init_crc(void)
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{
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    if (!crc_init) {
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        av_crc_init(crc_63, 0,  8,   0x63, sizeof(crc_63));
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        av_crc_init(crc_1D, 0,  8,   0x1D, sizeof(crc_1D));
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        av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
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        crc_init = 1;
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    }
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}
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uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
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{
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    uint16_t crc;
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    crc = av_crc(crc_2D, 0, buf, buf_size - 2);
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    crc ^= AV_RL16(buf + buf_size - 2);
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    return crc;
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}
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uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
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{
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    uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c
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    checksum ^= buf[buf_size-1];
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    return checksum;
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}
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uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
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{
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    int i;
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    int num_bytes = (bit_size + 2) / 8;
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    int crc = crc_1D[buf[0] & 0x3f];
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    crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2);
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    crc ^= buf[num_bytes - 1];
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    for (i = 0; i < ((bit_size + 2) & 7); i++) {
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        crc <<= 1;
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        if (crc & 0x100)
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            crc ^= 0x11D;
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        crc ^= (buf[num_bytes] >> (7 - i)) & 1;
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    }
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    return crc;
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}
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uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
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{
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    uint32_t scratch = 0;
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    const uint8_t *buf_end = buf + buf_size;
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    for (; ((intptr_t) buf & 3) && buf < buf_end; buf++)
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        scratch ^= *buf;
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    for (; buf < buf_end - 3; buf += 4)
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        scratch ^= *((const uint32_t*)buf);
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    scratch = xor_32_to_8(scratch);
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    for (; buf < buf_end; buf++)
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        scratch ^= *buf;
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    return scratch;
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}