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/*

 * 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_EXTENSION;

}

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 */

    if (!st->codec->channels || !st->codec->sample_rate)

        return AVERROR_INVALIDDATA;

    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,

};