/*

 * Copyright (C) 2017 foo86

 *

 * 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 "demux.h"

#include "internal.h"

#include "spdif.h"

#define MARKER_16LE         0x72F81F4E

#define MARKER_20LE         0x20876FF0E154

#define MARKER_24LE         0x72F8961F4EA5

#define IS_16LE_MARKER(state)   ((state & 0xFFFFFFFF) == MARKER_16LE)

#define IS_20LE_MARKER(state)   ((state & 0xF0FFFFF0FFFF) == MARKER_20LE)

#define IS_24LE_MARKER(state)   ((state & 0xFFFFFFFFFFFF) == MARKER_24LE)

#define IS_LE_MARKER(state)     (IS_16LE_MARKER(state) || IS_20LE_MARKER(state) || IS_24LE_MARKER(state))

static int s337m_get_offset_and_codec(void *avc,

                                      uint64_t state,

                                      int data_type, int data_size,

                                      int *offset, enum AVCodecID *codec)

{

    int word_bits;

    if (IS_16LE_MARKER(state)) {

        word_bits = 16;

    } else if (IS_20LE_MARKER(state)) {

        data_type >>= 8;

        data_size >>= 4;

        word_bits = 20;

    } else {

        data_type >>= 8;

        word_bits = 24;

    }

    if ((data_type & 0x1F) != 0x1C) {

        if (avc)

            avpriv_report_missing_feature(avc, "Data type %#x in SMPTE 337M", data_type & 0x1F);

        return AVERROR_PATCHWELCOME;

    }

    if (codec)

        *codec = AV_CODEC_ID_DOLBY_E;

    switch (data_size / word_bits) {

    case 3648:

        *offset = 1920;

        break;

    case 3644:

        *offset = 2002;

        break;

    case 3640:

        *offset = 2000;

        break;

    case 3040:

        *offset = 1601;

        break;

    default:

        if (avc)

            avpriv_report_missing_feature(avc, "Dolby E data size %d in SMPTE 337M", data_size);

        return AVERROR_PATCHWELCOME;

    }

    *offset -= 4;

    *offset *= (word_bits + 7 >> 3) * 2;

    return 0;

}

static int s337m_probe(const AVProbeData *p)

{

    uint64_t state = 0;

    int markers[3] = { 0 };

    int i, pos, sum, max, data_type, data_size, offset;

    uint8_t *buf;

    for (pos = 0; pos < p->buf_size; pos++) {

        state = (state << 8) | p->buf[pos];

        if (!IS_LE_MARKER(state))

            continue;

        buf = p->buf + pos + 1;

        if (IS_16LE_MARKER(state)) {

            data_type = AV_RL16(buf    );

            data_size = AV_RL16(buf + 2);

        } else {

            data_type = AV_RL24(buf    );

            data_size = AV_RL24(buf + 3);

        }

        if (s337m_get_offset_and_codec(NULL, state, data_type, data_size, &offset, NULL))

            continue;

        i = IS_16LE_MARKER(state) ? 0 : IS_20LE_MARKER(state) ? 1 : 2;

        markers[i]++;

        pos  += IS_16LE_MARKER(state) ? 4 : 6;

        pos  += offset;

        state = 0;

    }

    sum = max = 0;

    for (i = 0; i < FF_ARRAY_ELEMS(markers); i++) {

        sum += markers[i];

        if (markers[max] < markers[i])

            max = i;

    }

    if (markers[max] > 3 && markers[max] * 4 > sum * 3)

        return AVPROBE_SCORE_EXTENSION + 1;

    return 0;

}

static int s337m_read_header(AVFormatContext *s)

{

    s->ctx_flags |= AVFMTCTX_NOHEADER;

    return 0;

}

static void bswap_buf24(uint8_t *data, int size)

{

    int i;

    for (i = 0; i < size / 3; i++, data += 3)

        FFSWAP(uint8_t, data[0], data[2]);

}

static int s337m_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    AVIOContext *pb = s->pb;

    uint64_t state = 0;

    int ret, data_type, data_size, offset;

    enum AVCodecID codec;

    while (!IS_LE_MARKER(state)) {

        state = (state << 8) | avio_r8(pb);

        if (avio_feof(pb))

            return AVERROR_EOF;

    }

    if (IS_16LE_MARKER(state)) {

        data_type = avio_rl16(pb);

        data_size = avio_rl16(pb);

    } else {

        data_type = avio_rl24(pb);

        data_size = avio_rl24(pb);

    }

    if ((ret = s337m_get_offset_and_codec(s, state, data_type, data_size, &offset, &codec)) < 0)

        return ret;

    if ((ret = av_get_packet(pb, pkt, offset)) != offset)

        return ret < 0 ? ret : AVERROR_EOF;

    if (IS_16LE_MARKER(state))

        ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1);

    else

        bswap_buf24(pkt->data, pkt->size);

    if (!s->nb_streams) {

        AVStream *st = avformat_new_stream(s, NULL);

        if (!st) {

            return AVERROR(ENOMEM);

        }

        st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codecpar->codec_id   = codec;

        ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS;

    }

    return 0;

}

const FFInputFormat ff_s337m_demuxer = {

    .p.name         = "s337m",

    .p.long_name    = NULL_IF_CONFIG_SMALL("SMPTE 337M"),

    .p.flags        = AVFMT_GENERIC_INDEX,

    .read_probe     = s337m_probe,

    .read_header    = s337m_read_header,

    .read_packet    = s337m_read_packet,

};