/*

 * Interplay C93 demuxer

 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>

 *

 * 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 "avformat.h"

#include "avio_internal.h"

#include "demux.h"

#include "internal.h"

#include "voc.h"

#include "libavutil/intreadwrite.h"

typedef struct C93BlockRecord {

    uint16_t index;

    uint8_t length;

    uint8_t frames;

} C93BlockRecord;

typedef struct C93DemuxContext {

    VocDecContext voc;

    C93BlockRecord block_records[512];

    int current_block;

    uint32_t frame_offsets[32];

    int current_frame;

    int next_pkt_is_audio;

    AVStream *audio;

} C93DemuxContext;

static int probe(const AVProbeData *p)

{

    int i;

    int index = 1;

    if (p->buf_size < 16)

        return 0;

    for (i = 0; i < 16; i += 4) {

        if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])

            return 0;

        index += p->buf[i + 2];

    }

    return AVPROBE_SCORE_MAX;

}

static int read_header(AVFormatContext *s)

{

    AVStream *video;

    AVIOContext *pb = s->pb;

    C93DemuxContext *c93 = s->priv_data;

    int i;

    int framecount = 0;

    for (i = 0; i < 512; i++) {

        c93->block_records[i].index = avio_rl16(pb);

        c93->block_records[i].length = avio_r8(pb);

        c93->block_records[i].frames = avio_r8(pb);

        if (c93->block_records[i].frames > 32) {

            av_log(s, AV_LOG_ERROR, "too many frames in block\n");

            return AVERROR_INVALIDDATA;

        }

        framecount += c93->block_records[i].frames;

    }

    /* Audio streams are added if audio packets are found */

    s->ctx_flags |= AVFMTCTX_NOHEADER;

    video = avformat_new_stream(s, NULL);

    if (!video)

        return AVERROR(ENOMEM);

    video->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

    video->codecpar->codec_id = AV_CODEC_ID_C93;

    video->codecpar->width = 320;

    video->codecpar->height = 192;

    /* 4:3 320x200 with 8 empty lines */

    video->sample_aspect_ratio = (AVRational) { 5, 6 };

    avpriv_set_pts_info(video, 64, 2, 25);

    video->nb_frames = framecount;

    video->duration = framecount;

    video->start_time = 0;

    c93->current_block = 0;

    c93->current_frame = 0;

    c93->next_pkt_is_audio = 0;

    return 0;

}

#define C93_HAS_PALETTE 0x01

#define C93_FIRST_FRAME 0x02

static int read_packet(AVFormatContext *s, AVPacket *pkt)

{

    AVIOContext *pb = s->pb;

    C93DemuxContext *c93 = s->priv_data;

    C93BlockRecord *br = &c93->block_records[c93->current_block];

    int datasize;

    int ret, i;

    if (c93->next_pkt_is_audio) {

        c93->current_frame++;

        c93->next_pkt_is_audio = 0;

        datasize = avio_rl16(pb);

        if (datasize > 42) {

            if (!c93->audio) {

                c93->audio = avformat_new_stream(s, NULL);

                if (!c93->audio)

                    return AVERROR(ENOMEM);

                c93->audio->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

            }

            avio_skip(pb, 26); /* VOC header */

            ret = ff_voc_get_packet(s, pkt, c93->audio, datasize - 26);

            if (ret > 0) {

                pkt->stream_index = 1;

                pkt->flags |= AV_PKT_FLAG_KEY;

                return ret;

            }

        }

    }

    if (c93->current_frame >= br->frames) {

        if (c93->current_block >= 511 || !br[1].length)

            return AVERROR_EOF;

        br++;

        c93->current_block++;

        c93->current_frame = 0;

    }

    if (c93->current_frame == 0) {

        avio_seek(pb, br->index * 2048, SEEK_SET);

        for (i = 0; i < 32; i++) {

            c93->frame_offsets[i] = avio_rl32(pb);

        }

    }

    avio_seek(pb,br->index * 2048 +

            c93->frame_offsets[c93->current_frame], SEEK_SET);

    datasize = avio_rl16(pb); /* video frame size */

    ret = av_new_packet(pkt, datasize + 768 + 1);

    if (ret < 0)

        return ret;

    pkt->data[0] = 0;

    pkt->size = datasize + 1;

    ret = ffio_read_size(pb, pkt->data + 1, datasize);

    if (ret < 0) {

        return ret;

    }

    datasize = avio_rl16(pb); /* palette size */

    if (datasize) {

        if (datasize != 768) {

            av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);

            return AVERROR_INVALIDDATA;

        }

        pkt->data[0] |= C93_HAS_PALETTE;

        ret = ffio_read_size(pb, pkt->data + pkt->size, datasize);

        if (ret < 0) {

            return ret;

        }

        pkt->size += 768;

    }

    pkt->stream_index = 0;

    c93->next_pkt_is_audio = 1;

    /* only the first frame is guaranteed to not reference previous frames */

    if (c93->current_block == 0 && c93->current_frame == 0) {

        pkt->flags |= AV_PKT_FLAG_KEY;

        pkt->data[0] |= C93_FIRST_FRAME;

    }

    return 0;

}

const FFInputFormat ff_c93_demuxer = {

    .p.name         = "c93",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Interplay C93"),

    .priv_data_size = sizeof(C93DemuxContext),

    .read_probe     = probe,

    .read_header    = read_header,

    .read_packet    = read_packet,

};