/*

  * LucasArts VIMA decoder

  * Copyright (c) 2012 Paul B Mahol
  *
  * 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
  * LucasArts VIMA audio decoder
  * @author Paul B Mahol
  */
 

 #include "libavutil/channel_layout.h"

 
 #include "adpcm_data.h"

 #include "avcodec.h"
 #include "get_bits.h"

 #include "internal.h"

 static int predict_table_init = 0;
 static uint16_t predict_table[5786 * 2];

 static const uint8_t size_table[] = {

     4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
 };
 

 static const int8_t index_table1[] = {

     -1, 4, -1, 4
 };
 

 static const int8_t index_table2[] = {

     -1, -1, 2, 6, -1, -1, 2, 6
 };
 

 static const int8_t index_table3[] = {
     -1, -1, -1, -1, 1, 2, 4, 6, -1, -1, -1, -1, 1, 2, 4, 6

 };
 

 static const int8_t index_table4[] = {
     -1, -1, -1, -1, -1, -1, -1, -1, 1,  1,  1,  2,  2,  4,  5,  6,
     -1, -1, -1, -1, -1, -1, -1, -1, 1,  1,  1,  2,  2,  4,  5,  6

 };
 

 static const int8_t index_table5[] = {
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      1,  1,  1,  1,  1,  2,  2,  2,  2,  4,  4,  4,  5,  5,  6,  6,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      1,  1,  1,  1,  1,  2,  2,  2,  2,  4,  4,  4,  5,  5,  6,  6

 };
 

 static const int8_t index_table6[] = {
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  2,  2,
      2,  2,  4,  4,  4,  4,  4,  4,  5,  5,  5,  5,  6,  6,  6,  6,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  2,  2,
      2,  2,  4,  4,  4,  4,  4,  4,  5,  5,  5,  5,  6,  6,  6,  6

 };
 

 static const int8_t *const step_index_tables[] = {

     index_table1, index_table2, index_table3,
     index_table4, index_table5, index_table6
 };
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {

     int start_pos;
 
     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
 
     if (predict_table_init)
         return 0;

 
     for (start_pos = 0; start_pos < 64; start_pos++) {
         unsigned int dest_pos, table_pos;
 
         for (table_pos = 0, dest_pos = start_pos;
              table_pos < FF_ARRAY_ELEMS(ff_adpcm_step_table);
              table_pos++, dest_pos += 64) {
             int put = 0, count, table_value;
 
             table_value = ff_adpcm_step_table[table_pos];
             for (count = 32; count != 0; count >>= 1) {
                 if (start_pos & count)
                     put += table_value;
                 table_value >>= 1;
             }

             predict_table[dest_pos] = put;

         }
     }

     predict_table_init = 1;

 
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx, void *data,
                         int *got_frame_ptr, AVPacket *pkt)
 {

     GetBitContext gb;
     AVFrame *frame = data;
     int16_t pcm_data[2];
     uint32_t samples;
     int8_t channel_hint[2];
     int ret, chan;
     int channels = 1;

 
     if (pkt->size < 13)
         return AVERROR_INVALIDDATA;
 

     if ((ret = init_get_bits8(&gb, pkt->data, pkt->size)) < 0)
         return ret;

     samples = get_bits_long(&gb, 32);
     if (samples == 0xffffffff) {
         skip_bits_long(&gb, 32);
         samples = get_bits_long(&gb, 32);
     }
 
     if (samples > pkt->size * 2)
         return AVERROR_INVALIDDATA;
 
     channel_hint[0] = get_sbits(&gb, 8);
     if (channel_hint[0] & 0x80) {
         channel_hint[0] = ~channel_hint[0];
         channels = 2;
     }
     avctx->channels = channels;

     avctx->channel_layout = (channels == 2) ? AV_CH_LAYOUT_STEREO
                                             : AV_CH_LAYOUT_MONO;

     pcm_data[0] = get_sbits(&gb, 16);
     if (channels > 1) {
         channel_hint[1] = get_sbits(&gb, 8);

         pcm_data[1]     = get_sbits(&gb, 16);

     }
 

     frame->nb_samples = samples;

     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

         return ret;
 
     for (chan = 0; chan < channels; chan++) {

         uint16_t *dest = (uint16_t *)frame->data[0] + chan;

         int step_index = channel_hint[chan];
         int output = pcm_data[chan];
         int sample;
 
         for (sample = 0; sample < samples; sample++) {
             int lookup_size, lookup, highbit, lowbits;
 
             step_index  = av_clip(step_index, 0, 88);
             lookup_size = size_table[step_index];
             lookup      = get_bits(&gb, lookup_size);
             highbit     = 1 << (lookup_size - 1);
             lowbits     = highbit - 1;
 
             if (lookup & highbit)
                 lookup ^= highbit;
             else
                 highbit = 0;
 
             if (lookup == lowbits) {
                 output = get_sbits(&gb, 16);
             } else {
                 int predict_index, diff;
 
                 predict_index = (lookup << (7 - lookup_size)) | (step_index << 6);
                 predict_index = av_clip(predict_index, 0, 5785);

                 diff          = predict_table[predict_index];

                 if (lookup)
                     diff += ff_adpcm_step_table[step_index] >> (lookup_size - 1);
                 if (highbit)

                     diff = -diff;

                 output = av_clip_int16(output + diff);

             }
 
             *dest = output;
             dest += channels;
 
             step_index += step_index_tables[lookup_size - 2][lookup];
         }
     }
 

     *got_frame_ptr = 1;

 
     return pkt->size;
 }
 

 AVCodec ff_adpcm_vima_decoder = {
     .name         = "adpcm_vima",
     .long_name    = NULL_IF_CONFIG_SMALL("LucasArts VIMA audio"),
     .type         = AVMEDIA_TYPE_AUDIO,
     .id           = AV_CODEC_ID_ADPCM_VIMA,
     .init         = decode_init,
     .decode       = decode_frame,

     .capabilities = AV_CODEC_CAP_DR1,

 };