/*
  * Assorted DPCM codecs

  * Copyright (c) 2003 The ffmpeg Project

  *

  * 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

  */
 
 /**
  * @file: dpcm.c
  * Assorted DPCM (differential pulse code modulation) audio codecs
  * by Mike Melanson (melanson@pcisys.net)

  * Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt)

  * for more information on the specific data formats, visit:
  *   http://www.pcisys.net/~melanson/codecs/simpleaudio.html

  * SOL DPCMs implemented by Konstantin Shishkov

  *
  * Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files
  * found in the Wing Commander IV computer game. These AVI files contain
  * WAVEFORMAT headers which report the audio format as 0x01: raw PCM.
  * Clearly incorrect. To detect Xan DPCM, you will probably have to
  * special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan'
  * (Xan video) for its video codec. Alternately, such AVI files also contain
  * the fourcc 'Axan' in the 'auds' chunk of the AVI header.

  */
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 typedef struct DPCMContext {
     int channels;
     short roq_square_array[256];

     long sample[2];//for SOL_DPCM

     const int *sol_table;//for SOL_DPCM

 } DPCMContext;
 
 #define SE_16BIT(x)  if (x & 0x8000) x -= 0x10000;
 

 static const int interplay_delta_table[] = {

          0,      1,      2,      3,      4,      5,      6,      7,
          8,      9,     10,     11,     12,     13,     14,     15,
         16,     17,     18,     19,     20,     21,     22,     23,
         24,     25,     26,     27,     28,     29,     30,     31,
         32,     33,     34,     35,     36,     37,     38,     39,
         40,     41,     42,     43,     47,     51,     56,     61,
         66,     72,     79,     86,     94,    102,    112,    122,
        133,    145,    158,    173,    189,    206,    225,    245,
        267,    292,    318,    348,    379,    414,    452,    493,
        538,    587,    640,    699,    763,    832,    908,    991,
       1081,   1180,   1288,   1405,   1534,   1673,   1826,   1993,
       2175,   2373,   2590,   2826,   3084,   3365,   3672,   4008,
       4373,   4772,   5208,   5683,   6202,   6767,   7385,   8059,
       8794,   9597,  10472,  11428,  12471,  13609,  14851,  16206,
      17685,  19298,  21060,  22981,  25078,  27367,  29864,  32589,
     -29973, -26728, -23186, -19322, -15105, -10503,  -5481,     -1,
          1,      1,   5481,  10503,  15105,  19322,  23186,  26728,
      29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
     -17685, -16206, -14851, -13609, -12471, -11428, -10472,  -9597,
      -8794,  -8059,  -7385,  -6767,  -6202,  -5683,  -5208,  -4772,
      -4373,  -4008,  -3672,  -3365,  -3084,  -2826,  -2590,  -2373,
      -2175,  -1993,  -1826,  -1673,  -1534,  -1405,  -1288,  -1180,
      -1081,   -991,   -908,   -832,   -763,   -699,   -640,   -587,
       -538,   -493,   -452,   -414,   -379,   -348,   -318,   -292,
       -267,   -245,   -225,   -206,   -189,   -173,   -158,   -145,
       -133,   -122,   -112,   -102,    -94,    -86,    -79,    -72,
        -66,    -61,    -56,    -51,    -47,    -43,    -42,    -41,
        -40,    -39,    -38,    -37,    -36,    -35,    -34,    -33,
        -32,    -31,    -30,    -29,    -28,    -27,    -26,    -25,
        -24,    -23,    -22,    -21,    -20,    -19,    -18,    -17,
        -16,    -15,    -14,    -13,    -12,    -11,    -10,     -9,
         -8,     -7,     -6,     -5,     -4,     -3,     -2,     -1
 
 };
 

 static const int sol_table_old[16] =

     { 0x0,  0x1,  0x2 , 0x3,  0x6,  0xA,  0xF, 0x15,
     -0x15, -0xF, -0xA, -0x6, -0x3, -0x2, -0x1, 0x0};
 

 static const int sol_table_new[16] =

     { 0x0,  0x1,  0x2,  0x3,  0x6,  0xA,  0xF,  0x15,
       0x0, -0x1, -0x2, -0x3, -0x6, -0xA, -0xF, -0x15};

 static const int sol_table_16[128] = {

     0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
     0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
     0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
     0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
     0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
     0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
     0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
     0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
     0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
     0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
     0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
     0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
     0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
 };
 
 
 

 static av_cold int dpcm_decode_init(AVCodecContext *avctx)

 {
     DPCMContext *s = avctx->priv_data;
     int i;
     short square;
 
     s->channels = avctx->channels;

     s->sample[0] = s->sample[1] = 0;

 
     switch(avctx->codec->id) {
 
     case CODEC_ID_ROQ_DPCM:
         /* initialize square table */
         for (i = 0; i < 128; i++) {
             square = i * i;
             s->roq_square_array[i] = square;
             s->roq_square_array[i + 128] = -square;
         }
         break;
 

     case CODEC_ID_SOL_DPCM:
         switch(avctx->codec_tag){
         case 1:
             s->sol_table=sol_table_old;
             s->sample[0] = s->sample[1] = 0x80;
             break;
         case 2:
             s->sol_table=sol_table_new;
             s->sample[0] = s->sample[1] = 0x80;
             break;
         case 3:
             s->sol_table=sol_table_16;
             break;
         default:
             av_log(avctx, AV_LOG_ERROR, "Unknown SOL subcodec\n");
             return -1;
         }
         break;

     default:
         break;
     }
 

     avctx->sample_fmt = SAMPLE_FMT_S16;

     return 0;
 }
 
 static int dpcm_decode_frame(AVCodecContext *avctx,
                              void *data, int *data_size,

                              const uint8_t *buf, int buf_size)

 {
     DPCMContext *s = avctx->priv_data;
     int in, out = 0;
     int predictor[2];
     int channel_number = 0;
     short *output_samples = data;

     int shift[2];
     unsigned char byte;
     short diff;

     if (!buf_size)
         return 0;
 

     // almost every DPCM variant expands one byte of data into two
     if(*data_size/2 < buf_size)
         return -1;
 

     switch(avctx->codec->id) {
 
     case CODEC_ID_ROQ_DPCM:
         if (s->channels == 1)

             predictor[0] = AV_RL16(&buf[6]);

         else {
             predictor[0] = buf[7] << 8;
             predictor[1] = buf[6] << 8;
         }
         SE_16BIT(predictor[0]);
         SE_16BIT(predictor[1]);
 
         /* decode the samples */
         for (in = 8, out = 0; in < buf_size; in++, out++) {
             predictor[channel_number] += s->roq_square_array[buf[in]];

             predictor[channel_number] = av_clip_int16(predictor[channel_number]);

             output_samples[out] = predictor[channel_number];
 
             /* toggle channel */
             channel_number ^= s->channels - 1;
         }
         break;
 
     case CODEC_ID_INTERPLAY_DPCM:

         in = 6;  /* skip over the stream mask and stream length */

         predictor[0] = AV_RL16(&buf[in]);

         in += 2;
         SE_16BIT(predictor[0])
         output_samples[out++] = predictor[0];
         if (s->channels == 2) {

             predictor[1] = AV_RL16(&buf[in]);

             in += 2;

             SE_16BIT(predictor[1])
             output_samples[out++] = predictor[1];

         }
 
         while (in < buf_size) {
             predictor[channel_number] += interplay_delta_table[buf[in++]];

             predictor[channel_number] = av_clip_int16(predictor[channel_number]);

             output_samples[out++] = predictor[channel_number];
 
             /* toggle channel */
             channel_number ^= s->channels - 1;
         }
 
         break;

 
     case CODEC_ID_XAN_DPCM:
         in = 0;
         shift[0] = shift[1] = 4;

         predictor[0] = AV_RL16(&buf[in]);

         in += 2;
         SE_16BIT(predictor[0]);
         if (s->channels == 2) {

             predictor[1] = AV_RL16(&buf[in]);

             in += 2;
             SE_16BIT(predictor[1]);
         }
 
         while (in < buf_size) {
             byte = buf[in++];
             diff = (byte & 0xFC) << 8;
             if ((byte & 0x03) == 3)
                 shift[channel_number]++;
             else
                 shift[channel_number] -= (2 * (byte & 3));
             /* saturate the shifter to a lower limit of 0 */
             if (shift[channel_number] < 0)
                 shift[channel_number] = 0;
 
             diff >>= shift[channel_number];
             predictor[channel_number] += diff;
 

             predictor[channel_number] = av_clip_int16(predictor[channel_number]);

             output_samples[out++] = predictor[channel_number];
 
             /* toggle channel */
             channel_number ^= s->channels - 1;
         }
         break;

     case CODEC_ID_SOL_DPCM:
         in = 0;
         if (avctx->codec_tag != 3) {

             if(*data_size/4 < buf_size)
                 return -1;

             while (in < buf_size) {
                 int n1, n2;
                 n1 = (buf[in] >> 4) & 0xF;
                 n2 = buf[in++] & 0xF;
                 s->sample[0] += s->sol_table[n1];

                 if (s->sample[0] < 0) s->sample[0] = 0;

                 if (s->sample[0] > 255) s->sample[0] = 255;
                 output_samples[out++] = (s->sample[0] - 128) << 8;
                 s->sample[s->channels - 1] += s->sol_table[n2];
                 if (s->sample[s->channels - 1] < 0) s->sample[s->channels - 1] = 0;
                 if (s->sample[s->channels - 1] > 255) s->sample[s->channels - 1] = 255;
                 output_samples[out++] = (s->sample[s->channels - 1] - 128) << 8;
             }
         } else {
             while (in < buf_size) {
                 int n;
                 n = buf[in++];
                 if (n & 0x80) s->sample[channel_number] -= s->sol_table[n & 0x7F];
                 else s->sample[channel_number] += s->sol_table[n & 0x7F];

                 s->sample[channel_number] = av_clip_int16(s->sample[channel_number]);

                 output_samples[out++] = s->sample[channel_number];
                 /* toggle channel */
                 channel_number ^= s->channels - 1;
             }
         }
         break;

     }
 
     *data_size = out * sizeof(short);
     return buf_size;
 }
 

 #define DPCM_DECODER(id, name, long_name_)      \

 AVCodec name ## _decoder = {                    \
     #name,                                      \
     CODEC_TYPE_AUDIO,                           \
     id,                                         \
     sizeof(DPCMContext),                        \
     dpcm_decode_init,                           \
     NULL,                                       \
     NULL,                                       \
     dpcm_decode_frame,                          \

     .long_name = NULL_IF_CONFIG_SMALL(long_name_), \

 };
 

 DPCM_DECODER(CODEC_ID_INTERPLAY_DPCM, interplay_dpcm, "DPCM Interplay");
 DPCM_DECODER(CODEC_ID_ROQ_DPCM, roq_dpcm, "DPCM id RoQ");
 DPCM_DECODER(CODEC_ID_SOL_DPCM, sol_dpcm, "DPCM Sol");
 DPCM_DECODER(CODEC_ID_XAN_DPCM, xan_dpcm, "DPCM Xan");