/*
  * ADX ADPCM codecs
  * Copyright (c) 2001,2003 BERO
  *

  * 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 "libavutil/intreadwrite.h"

 #include "avcodec.h"

 #include "adx.h"

 
 /**

  * @file

  * SEGA CRI adx codecs.
  *
  * Reference documents:
  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  */
 

 static av_cold int adx_decode_init(AVCodecContext *avctx)

 {

     avctx->sample_fmt = AV_SAMPLE_FMT_S16;

     return 0;
 }
 

 /* 18 bytes <-> 32 samples */

 
 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
 {

     int scale = AV_RB16(in);

     int i;
     int s0,s1,s2,d;
 
 //    printf("%x ",scale);
 
     in+=2;
     s1 = prev->s1;
     s2 = prev->s2;
     for(i=0;i<16;i++) {
         d = in[i];
         // d>>=4; if (d&8) d-=16;
         d = ((signed char)d >> 4);
         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
         s2 = s1;

         s1 = av_clip_int16(s0);
         *out++=s1;

 
         d = in[i];
         //d&=15; if (d&8) d-=16;
         d = ((signed char)(d<<4) >> 4);
         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
         s2 = s1;

         s1 = av_clip_int16(s0);
         *out++=s1;

     }
     prev->s1 = s1;
     prev->s2 = s2;

 
 }
 
 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
 {

     short tmp[32*2];
     int i;
 
     adx_decode(tmp   ,in   ,prev);
     adx_decode(tmp+32,in+18,prev+1);
     for(i=0;i<32;i++) {
         out[i*2]   = tmp[i];
         out[i*2+1] = tmp[i+32];
     }

 }
 

 /* return data offset or 0 */
 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)

 {

     int offset;

     if (buf[0]!=0x80) return 0;

     offset = (AV_RB32(buf)^0x80000000)+4;

     if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;

     avctx->channels    = buf[7];
     avctx->sample_rate = AV_RB32(buf+8);
     avctx->bit_rate    = avctx->sample_rate*avctx->channels*18*8/32;

     return offset;

 }
 
 static int adx_decode_frame(AVCodecContext *avctx,

                 void *data, int *data_size,

                 AVPacket *avpkt)

 {

     const uint8_t *buf0 = avpkt->data;
     int buf_size = avpkt->size;

     ADXContext *c = avctx->priv_data;
     short *samples = data;
     const uint8_t *buf = buf0;
     int rest = buf_size;
 
     if (!c->header_parsed) {
         int hdrsize = adx_decode_header(avctx,buf,rest);
         if (hdrsize==0) return -1;
         c->header_parsed = 1;
         buf  += hdrsize;
         rest -= hdrsize;
     }
 

     /* 18 bytes of data are expanded into 32*2 bytes of audio,
        so guard against buffer overflows */
     if(rest/18 > *data_size/64)
         rest = (*data_size/64) * 18;
 

     if (c->in_temp) {
         int copysize = 18*avctx->channels - c->in_temp;
         memcpy(c->dec_temp+c->in_temp,buf,copysize);
         rest -= copysize;
         buf  += copysize;
         if (avctx->channels==1) {
             adx_decode(samples,c->dec_temp,c->prev);
             samples += 32;
         } else {
             adx_decode_stereo(samples,c->dec_temp,c->prev);
             samples += 32*2;
         }
     }
     //
     if (avctx->channels==1) {
         while(rest>=18) {
             adx_decode(samples,buf,c->prev);
             rest-=18;
             buf+=18;
             samples+=32;
         }
     } else {
         while(rest>=18*2) {
             adx_decode_stereo(samples,buf,c->prev);
             rest-=18*2;
             buf+=18*2;
             samples+=32*2;
         }
     }
     //
     c->in_temp = rest;
     if (rest) {
         memcpy(c->dec_temp,buf,rest);
         buf+=rest;
     }
     *data_size = (uint8_t*)samples - (uint8_t*)data;
 //    printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
     return buf-buf0;

 }
 

 AVCodec ff_adpcm_adx_decoder = {

     "adpcm_adx",

     AVMEDIA_TYPE_AUDIO,

     CODEC_ID_ADPCM_ADX,
     sizeof(ADXContext),

     adx_decode_init,

     NULL,
     NULL,
     adx_decode_frame,

     .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),

 };