/*
  * Maxis XA (.xa) File Demuxer
  * Copyright (c) 2008 Robert Marston
  *
  * 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

  * Maxis XA File Demuxer
  * by Robert Marston (rmarston@gmail.com)
  * for more information on the XA audio format see
  *   http://wiki.multimedia.cx/index.php?title=Maxis_XA
  */
 

 #include "libavutil/intreadwrite.h"

 #include "avformat.h"

 #include "internal.h"

 
 #define XA00_TAG MKTAG('X', 'A', 0, 0)
 #define XAI0_TAG MKTAG('X', 'A', 'I', 0)
 #define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
 
 typedef struct MaxisXADemuxContext {
     uint32_t out_size;
     uint32_t sent_bytes;
 } MaxisXADemuxContext;
 
 static int xa_probe(AVProbeData *p)
 {

     int channels, srate, bits_per_sample;
     if (p->buf_size < 24)
         return 0;

     switch(AV_RL32(p->buf)) {
     case XA00_TAG:
     case XAI0_TAG:
     case XAJ0_TAG:

         break;
     default:
         return 0;

     }

     channels        = AV_RL16(p->buf + 10);
     srate           = AV_RL32(p->buf + 12);
     bits_per_sample = AV_RL16(p->buf + 22);
     if (!channels || channels > 8 || !srate || srate > 192000 ||
         bits_per_sample < 4 || bits_per_sample > 32)
         return 0;
     return AVPROBE_SCORE_MAX/2;

 }
 

 static int xa_read_header(AVFormatContext *s)

 {
     MaxisXADemuxContext *xa = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *st;
 
     /*Set up the XA Audio Decoder*/

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);
 

     st->codec->codec_type   = AVMEDIA_TYPE_AUDIO;

     st->codec->codec_id     = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;

     avio_skip(pb, 4);       /* Skip the XA ID */

     xa->out_size            =  avio_rl32(pb);

     avio_skip(pb, 2);       /* Skip the tag */

     st->codec->channels     = avio_rl16(pb);
     st->codec->sample_rate  = avio_rl32(pb);

     avio_skip(pb, 4);       /* Skip average byte rate */
     avio_skip(pb, 2);       /* Skip block align */
     avio_skip(pb, 2);       /* Skip bits-per-sample */

     st->codec->bit_rate = av_clip(15LL * st->codec->channels * 8 *
                                   st->codec->sample_rate / 28, 0, INT_MAX);

     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

     st->start_time = 0;

 
     return 0;
 }
 
 static int xa_read_packet(AVFormatContext *s,
                           AVPacket *pkt)
 {
     MaxisXADemuxContext *xa = s->priv_data;
     AVStream *st = s->streams[0];

     AVIOContext *pb = s->pb;

     unsigned int packet_size;
     int ret;
 

     if (xa->sent_bytes >= xa->out_size)
         return AVERROR_EOF;

     /* 1 byte header and 14 bytes worth of samples * number channels per block */
     packet_size = 15*st->codec->channels;
 
     ret = av_get_packet(pb, pkt, packet_size);

     if(ret < 0)
         return ret;

 
     pkt->stream_index = st->index;
     xa->sent_bytes += packet_size;

     pkt->duration = 28;

 
     return ret;
 }
 

 AVInputFormat ff_xa_demuxer = {

     .name           = "xa",

     .long_name      = NULL_IF_CONFIG_SMALL("Maxis XA"),

     .priv_data_size = sizeof(MaxisXADemuxContext),
     .read_probe     = xa_probe,
     .read_header    = xa_read_header,
     .read_packet    = xa_read_packet,

 };