/*
  * 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;
 static AVCRC crc_63[1024];
 static AVCRC crc_1D[1024];
 static AVCRC crc_2D[1024];
 

 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 (; 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;
 }