/*
  * ISS (.iss) file demuxer
  * Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
  *
  * 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

  * Funcom ISS file demuxer
  * @author Jaikrishnan Menon

  * @see http://wiki.multimedia.cx/index.php?title=FunCom_ISS

  */
 
 #include "avformat.h"

 #include "internal.h"

 #include "libavutil/avstring.h"
 
 #define ISS_SIG "IMA_ADPCM_Sound"
 #define ISS_SIG_LEN 15
 #define MAX_TOKEN_SIZE 20
 
 typedef struct {
     int packet_size;
     int sample_start_pos;
 } IssDemuxContext;
 

 static void get_token(AVIOContext *s, char *buf, int maxlen)

 {
     int i = 0;
     char c;
 

     while ((c = avio_r8(s))) {

         if(c == ' ')
             break;
         if (i < maxlen-1)
             buf[i++] = c;
     }
 

     if(!c)

         avio_r8(s);

     buf[i] = 0; /* Ensure null terminated, but may be truncated */
 }
 
 static int iss_probe(AVProbeData *p)
 {
     if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))
         return 0;
 
     return AVPROBE_SCORE_MAX;
 }
 

 static av_cold int iss_read_header(AVFormatContext *s)

 {
     IssDemuxContext *iss = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *st;
     char token[MAX_TOKEN_SIZE];
     int stereo, rate_divisor;
 
     get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"
     get_token(pb, token, sizeof(token)); //packet size
     sscanf(token, "%d", &iss->packet_size);
     get_token(pb, token, sizeof(token)); //File ID
     get_token(pb, token, sizeof(token)); //out size
     get_token(pb, token, sizeof(token)); //stereo
     sscanf(token, "%d", &stereo);
     get_token(pb, token, sizeof(token)); //Unknown1
     get_token(pb, token, sizeof(token)); //RateDivisor
     sscanf(token, "%d", &rate_divisor);
     get_token(pb, token, sizeof(token)); //Unknown2
     get_token(pb, token, sizeof(token)); //Version ID
     get_token(pb, token, sizeof(token)); //Size
 

     if (iss->packet_size <= 0) {
         av_log(s, AV_LOG_ERROR, "packet_size %d is invalid\n", iss->packet_size);
         return AVERROR_INVALIDDATA;
     }
 

     iss->sample_start_pos = avio_tell(pb);

     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_IMA_ISS;

     st->codec->channels = stereo ? 2 : 1;
     st->codec->sample_rate = 44100;
     if(rate_divisor > 0)
          st->codec->sample_rate /= rate_divisor;
     st->codec->bits_per_coded_sample = 4;
     st->codec->bit_rate = st->codec->channels * st->codec->sample_rate
                                       * st->codec->bits_per_coded_sample;
     st->codec->block_align = iss->packet_size;

     avpriv_set_pts_info(st, 32, 1, st->codec->sample_rate);

 
     return 0;
 }
 
 static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     IssDemuxContext *iss = s->priv_data;
     int ret = av_get_packet(s->pb, pkt, iss->packet_size);
 

     if(ret != iss->packet_size)
         return AVERROR(EIO);

 
     pkt->stream_index = 0;

     pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;

     if(s->streams[0]->codec->channels > 0)
         pkt->pts /= s->streams[0]->codec->channels*2;
     return 0;
 }
 

 AVInputFormat ff_iss_demuxer = {

     .name           = "iss",

     .long_name      = NULL_IF_CONFIG_SMALL("Funcom ISS"),

     .priv_data_size = sizeof(IssDemuxContext),
     .read_probe     = iss_probe,
     .read_header    = iss_read_header,
     .read_packet    = iss_read_packet,

 };