/*

 * 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 "libavutil/channel_layout.h"

#include "avformat.h"

#include "demux.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 IssDemuxContext {

    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(const 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

    if (sscanf(token, "%d", &iss->packet_size) != 1) {

        av_log(s, AV_LOG_ERROR, "Failed parsing packet size\n");

        return AVERROR_INVALIDDATA;

    }

    get_token(pb, token, sizeof(token)); //File ID

    get_token(pb, token, sizeof(token)); //out size

    get_token(pb, token, sizeof(token)); //stereo

    if (sscanf(token, "%d", &stereo) != 1) {

        av_log(s, AV_LOG_ERROR, "Failed parsing stereo flag\n");

        return AVERROR_INVALIDDATA;

    }

    get_token(pb, token, sizeof(token)); //Unknown1

    get_token(pb, token, sizeof(token)); //RateDivisor

    if (sscanf(token, "%d", &rate_divisor) != 1) {

        av_log(s, AV_LOG_ERROR, "Failed parsing rate_divisor\n");

        return AVERROR_INVALIDDATA;

    }

    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->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_ISS;

    if (stereo) {

        st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;

    } else {

        st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    }

    st->codecpar->sample_rate = 44100;

    if(rate_divisor > 0)

         st->codecpar->sample_rate /= rate_divisor;

    st->codecpar->bits_per_coded_sample = 4;

    st->codecpar->bit_rate = st->codecpar->ch_layout.nb_channels *

                             st->codecpar->sample_rate *

                             st->codecpar->bits_per_coded_sample;

    st->codecpar->block_align = iss->packet_size;

    avpriv_set_pts_info(st, 32, 1, st->codecpar->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]->codecpar->ch_layout.nb_channels > 0)

        pkt->pts /= s->streams[0]->codecpar->ch_layout.nb_channels * 2;

    return 0;

}

const FFInputFormat ff_iss_demuxer = {

    .p.name         = "iss",

    .p.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,

};