/*
  * Copyright (C) 2008 Jaikrishnan Menon

  * Copyright (C) 2011 Stefano Sabatini

  *
  * 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

  * 8svx audio decoder
  * @author Jaikrishnan Menon

  *

  * supports: fibonacci delta encoding
  *         : exponential encoding

  *
  * For more information about the 8SVX format:
  * http://netghost.narod.ru/gff/vendspec/iff/iff.txt
  * http://sox.sourceforge.net/AudioFormats-11.html
  * http://aminet.net/package/mus/misc/wavepak
  * http://amigan.1emu.net/reg/8SVX.txt
  *
  * Samples can be found here:
  * http://aminet.net/mods/smpl/

  */
 

 #include "libavutil/avassert.h"

 #include "avcodec.h"

 #include "internal.h"

 #include "libavutil/common.h"

 /** decoder context */

 typedef struct EightSvxContext {

     uint8_t fib_acc[2];

     const int8_t *table;
 

     /* buffer used to store the whole first packet.
        data is only sent as one large packet */
     uint8_t *data[2];
     int data_size;
     int data_idx;

 } EightSvxContext;
 

 static const int8_t fibonacci[16]   = { -34,  -21, -13,  -8, -5, -3, -2, -1, 0, 1, 2, 3, 5, 8,  13, 21 };
 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1, 0, 1, 2, 4, 8, 16, 32, 64 };
 
 #define MAX_FRAME_SIZE 2048
 
 /**
  * Delta decode the compressed values in src, and put the resulting

  * decoded samples in dst.

  *

  * @param[in,out] state starting value. it is saved for use in the next call.

  * @param table delta sequence table
  */

 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
                          uint8_t *state, const int8_t *table)

 {

     uint8_t val = *state;

     while (src_size--) {

         uint8_t d = *src++;

         val = av_clip_uint8(val + table[d & 0xF]);

         *dst++ = val;

         val = av_clip_uint8(val + table[d >> 4]);

         *dst++ = val;
     }
 

     *state = val;

 }

 /** decode a frame */

 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
                                  int *got_frame_ptr, AVPacket *avpkt)

 {
     EightSvxContext *esc = avctx->priv_data;

     AVFrame *frame       = data;

     int buf_size;

     int ch, ret;

     int hdr_size = 2;

     /* decode and interleave the first packet */

     if (!esc->data[0] && avpkt) {
         int chan_size = avpkt->size / avctx->channels - hdr_size;

         if (avpkt->size % avctx->channels) {

             av_log(avctx, AV_LOG_WARNING, "Packet with odd size, ignoring last byte\n");
         }

         if (avpkt->size < (hdr_size + 1) * avctx->channels) {
             av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");

             return AVERROR_INVALIDDATA;

         }

         esc->fib_acc[0] = avpkt->data[1] + 128;
         if (avctx->channels == 2)
             esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;

         esc->data_idx  = 0;
         esc->data_size = chan_size;
         if (!(esc->data[0] = av_malloc(chan_size)))
             return AVERROR(ENOMEM);
         if (avctx->channels == 2) {
             if (!(esc->data[1] = av_malloc(chan_size))) {
                 av_freep(&esc->data[0]);
                 return AVERROR(ENOMEM);

             }

         }

         memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
         if (avctx->channels == 2)
             memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
     }
     if (!esc->data[0]) {
         av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* decode next piece of data from the buffer */
     buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
     if (buf_size <= 0) {
         *got_frame_ptr = 0;
         return avpkt->size;

     }
 

     /* get output buffer */

     frame->nb_samples = buf_size * 2;

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

         return ret;

     for (ch = 0; ch < avctx->channels; ch++) {

         delta_decode(frame->data[ch], &esc->data[ch][esc->data_idx],

                      buf_size, &esc->fib_acc[ch], esc->table);

     }
 
     esc->data_idx += buf_size;
 

     *got_frame_ptr = 1;

     return ((avctx->frame_number == 0)*hdr_size + buf_size)*avctx->channels;

 }
 
 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
 {
     EightSvxContext *esc = avctx->priv_data;
 

     if (avctx->channels < 1 || avctx->channels > 2) {

         av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
         return AVERROR_INVALIDDATA;

     }

 
     switch (avctx->codec->id) {

     case AV_CODEC_ID_8SVX_FIB: esc->table = fibonacci;    break;
     case AV_CODEC_ID_8SVX_EXP: esc->table = exponential;  break;

     default:
         av_log(avctx, AV_LOG_ERROR, "Invalid codec id %d.\n", avctx->codec->id);
         return AVERROR_INVALIDDATA;
     }

     avctx->sample_fmt = AV_SAMPLE_FMT_U8P;

 
     return 0;
 }
 
 static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
 {
     EightSvxContext *esc = avctx->priv_data;
 

     av_freep(&esc->data[0]);
     av_freep(&esc->data[1]);
     esc->data_size = 0;
     esc->data_idx = 0;

     return 0;
 }
 

 #if CONFIG_EIGHTSVX_FIB_DECODER

 AVCodec ff_eightsvx_fib_decoder = {

   .name           = "8svx_fib",

   .long_name      = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),

   .type           = AVMEDIA_TYPE_AUDIO,

   .id             = AV_CODEC_ID_8SVX_FIB,

   .priv_data_size = sizeof (EightSvxContext),
   .init           = eightsvx_decode_init,
   .decode         = eightsvx_decode_frame,

   .close          = eightsvx_decode_close,

   .capabilities   = AV_CODEC_CAP_DR1,

   .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
                                                     AV_SAMPLE_FMT_NONE },

 };

 #endif
 #if CONFIG_EIGHTSVX_EXP_DECODER

 AVCodec ff_eightsvx_exp_decoder = {

   .name           = "8svx_exp",

   .long_name      = NULL_IF_CONFIG_SMALL("8SVX exponential"),

   .type           = AVMEDIA_TYPE_AUDIO,

   .id             = AV_CODEC_ID_8SVX_EXP,

   .priv_data_size = sizeof (EightSvxContext),
   .init           = eightsvx_decode_init,
   .decode         = eightsvx_decode_frame,

   .close          = eightsvx_decode_close,

   .capabilities   = AV_CODEC_CAP_DR1,

   .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
                                                     AV_SAMPLE_FMT_NONE },

 };

 #endif