/*
  * VPK demuxer
  * Copyright (c) 2015 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
  */
 
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
 #include "internal.h"
 
 typedef struct VPKDemuxContext {
     unsigned block_count;
     unsigned current_block;
     unsigned last_block_size;
 } VPKDemuxContext;
 
 static int vpk_probe(AVProbeData *p)
 {
     if (AV_RL32(p->buf) != MKBETAG('V','P','K',' '))
         return 0;
 
     return AVPROBE_SCORE_MAX / 3 * 2;
 }
 
 static int vpk_read_header(AVFormatContext *s)
 {
     VPKDemuxContext *vpk = s->priv_data;
     unsigned offset;
     unsigned samples_per_block;
     AVStream *st;
 
     vpk->current_block = 0;
     st = avformat_new_stream(s, NULL);
     if (!st)
         return AVERROR(ENOMEM);
 
     avio_skip(s->pb, 4);
     st->duration           = avio_rl32(s->pb) * 28 / 16;
     offset                 = avio_rl32(s->pb);

     st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
     st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_PSX;
     st->codecpar->block_align = avio_rl32(s->pb);
     st->codecpar->sample_rate = avio_rl32(s->pb);
     if (st->codecpar->sample_rate <= 0)

         return AVERROR_INVALIDDATA;

     st->codecpar->channels    = avio_rl32(s->pb);
     if (st->codecpar->channels <= 0)

         return AVERROR_INVALIDDATA;

     samples_per_block      = ((st->codecpar->block_align / st->codecpar->channels) * 28) / 16;

     if (samples_per_block <= 0)
         return AVERROR_INVALIDDATA;

     vpk->block_count       = (st->duration + (samples_per_block - 1)) / samples_per_block;

     vpk->last_block_size   = (st->duration % samples_per_block) * 16 * st->codecpar->channels / 28;

     avio_skip(s->pb, offset - avio_tell(s->pb));

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

 
     return 0;
 }
 
 static int vpk_read_packet(AVFormatContext *s, AVPacket *pkt)
 {

     AVCodecParameters *par = s->streams[0]->codecpar;

     VPKDemuxContext *vpk = s->priv_data;
     int ret, i;
 
     vpk->current_block++;
     if (vpk->current_block == vpk->block_count) {

         unsigned size = vpk->last_block_size / par->channels;
         unsigned skip = (par->block_align - vpk->last_block_size) / par->channels;

 
         ret = av_new_packet(pkt, vpk->last_block_size);
         if (ret < 0)
             return ret;

         for (i = 0; i < par->channels; i++) {

             ret = avio_read(s->pb, pkt->data + i * size, size);
             avio_skip(s->pb, skip);
             if (ret != size) {
                 av_packet_unref(pkt);
                 ret = AVERROR(EIO);
                 break;
             }
         }
         pkt->stream_index = 0;
     } else if (vpk->current_block < vpk->block_count) {

         ret = av_get_packet(s->pb, pkt, par->block_align);

         pkt->stream_index = 0;
     } else {
         return AVERROR_EOF;
     }
 
     return ret;
 }
 
 AVInputFormat ff_vpk_demuxer = {
     .name           = "vpk",
     .long_name      = NULL_IF_CONFIG_SMALL("Sony PS2 VPK"),
     .priv_data_size = sizeof(VPKDemuxContext),
     .read_probe     = vpk_probe,
     .read_header    = vpk_read_header,
     .read_packet    = vpk_read_packet,
     .extensions     = "vpk",
 };