/*
  * tables and functions for demuxing SIPR audio muxed RealMedia style
  *

  * 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 "rmsipr.h"
 
 const unsigned char ff_sipr_subpk_size[4] = { 29, 19, 37, 20 };
 
 static const unsigned char sipr_swaps[38][2] = {
     {  0, 63 }, {  1, 22 }, {  2, 44 }, {  3, 90 },
     {  5, 81 }, {  7, 31 }, {  8, 86 }, {  9, 58 },
     { 10, 36 }, { 12, 68 }, { 13, 39 }, { 14, 73 },
     { 15, 53 }, { 16, 69 }, { 17, 57 }, { 19, 88 },
     { 20, 34 }, { 21, 71 }, { 24, 46 }, { 25, 94 },
     { 26, 54 }, { 28, 75 }, { 29, 50 }, { 32, 70 },
     { 33, 92 }, { 35, 74 }, { 38, 85 }, { 40, 56 },
     { 42, 87 }, { 43, 65 }, { 45, 59 }, { 48, 79 },
     { 49, 93 }, { 51, 89 }, { 55, 95 }, { 61, 76 },
     { 67, 83 }, { 77, 80 }
 };
 
 /* This can be optimized, e.g. use memcpy() if data blocks are aligned. */
 void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize)
 {
     int n, bs = sub_packet_h * framesize * 2 / 96; // nibbles per subpacket
 
     for (n = 0; n < 38; n++) {
         int j;
         int i = bs * sipr_swaps[n][0];
         int o = bs * sipr_swaps[n][1];
 
         /* swap 4bit-nibbles of block 'i' with 'o' */
         for (j = 0; j < bs; j++, i++, o++) {
             int x = (buf[i >> 1] >> (4 * (i & 1))) & 0xF,
                 y = (buf[o >> 1] >> (4 * (o & 1))) & 0xF;
 
             buf[o >> 1] = (x << (4 * (o & 1))) |
                 (buf[o >> 1] & (0xF << (4 * !(o & 1))));
             buf[i >> 1] = (y << (4 * (i & 1))) |
                 (buf[i >> 1] & (0xF << (4 * !(i & 1))));
         }
     }
 }