/*

 * MLP parser

 * Copyright (c) 2007 Ian Caulfield

 *

 * 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

 * MLP parser

 */

#include <stdint.h>

#include "libavutil/internal.h"

#include "get_bits.h"

#include "parser.h"

#include "mlp_parse.h"

#include "mlp.h"

typedef struct MLPParseContext

{

    ParseContext pc;

    int bytes_left;

    int in_sync;

    int num_substreams;

} MLPParseContext;

static av_cold int mlp_init(AVCodecParserContext *s)

{

    ff_mlp_init_crc();

    return 0;

}

static int mlp_parse(AVCodecParserContext *s,

                     AVCodecContext *avctx,

                     const uint8_t **poutbuf, int *poutbuf_size,

                     const uint8_t *buf, int buf_size)

{

    MLPParseContext *mp = s->priv_data;

    int sync_present;

    uint8_t parity_bits;

    int next;

    int ret;

    int i, p = 0;

    s->key_frame = 0;

    *poutbuf_size = 0;

    *poutbuf = NULL;

    if (buf_size == 0)

        return 0;

    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {

        next = buf_size;

    } else {

        if (!mp->in_sync) {

            // Not in sync - find a major sync header

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

                mp->pc.state = (mp->pc.state << 8) | buf[i];

                if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&

                    // ignore if we do not have the data for the start of header

                    mp->pc.index + i >= 7) {

                    mp->in_sync = 1;

                    mp->bytes_left = 0;

                    break;

                }

            }

            if (!mp->in_sync) {

                if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)

                    av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

                return buf_size;

            }

            if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) {

                av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

                return ret;

            }

            return i - 7;

        }

        if (mp->bytes_left == 0) {

            // Find length of this packet

            /* Copy overread bytes from last frame into buffer. */

            for(; mp->pc.overread>0; mp->pc.overread--) {

                mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];

            }

            if (mp->pc.index + buf_size < 2) {

                if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)

                    av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

                return buf_size;

            }

            mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)

                           |  (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);

            mp->bytes_left = (mp->bytes_left & 0xfff) * 2;

            if (mp->bytes_left <= 0) { // prevent infinite loop

                goto lost_sync;

            }

            mp->bytes_left -= mp->pc.index;

        }

        next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;

        if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {

            mp->bytes_left -= buf_size;

            return buf_size;

        }

        mp->bytes_left = 0;

    }

    sync_present = buf_size >= 8 && (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;

    if (!sync_present) {

        /* The first nibble of a frame is a parity check of the 4-byte

         * access unit header and all the 2- or 4-byte substream headers. */

        // Only check when this isn't a sync frame - syncs have a checksum.

        s->key_frame = 0;

        parity_bits = 0;

        for (i = -1; i < mp->num_substreams; i++) {

            parity_bits ^= buf[p++];

            parity_bits ^= buf[p++];

            if (i < 0 || buf[p-2] & 0x80) {

                parity_bits ^= buf[p++];

                parity_bits ^= buf[p++];

            }

        }

        if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {

            av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");

            goto lost_sync;

        }

    } else {

        GetBitContext gb;

        MLPHeaderInfo mh;

        init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);

        if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)

            goto lost_sync;

        s->key_frame = 1;

        avctx->bits_per_raw_sample = mh.group1_bits;

        if (avctx->bits_per_raw_sample > 16)

            avctx->sample_fmt = AV_SAMPLE_FMT_S32;

        else

            avctx->sample_fmt = AV_SAMPLE_FMT_S16;

        avctx->sample_rate = mh.group1_samplerate;

        avctx->frame_size =

        s->duration = mh.access_unit_size;

        av_channel_layout_uninit(&avctx->ch_layout);

        if (mh.stream_type == 0xbb) {

            /* MLP stream */

            av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_mlp);

        } else { /* mh.stream_type == 0xba */

            /* TrueHD stream */

            if (!mh.channels_thd_stream2) {

                av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream1);

            } else {

                av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream2);

            }

        }

        if (!mh.is_vbr) /* Stream is CBR */

            avctx->bit_rate = mh.peak_bitrate;

        mp->num_substreams = mh.num_substreams;

    }

    *poutbuf = buf;

    *poutbuf_size = buf_size;

    return next;

lost_sync:

    mp->in_sync = 0;

    return 1;

}

const AVCodecParser ff_mlp_parser = {

    .codec_ids      = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD },

    .priv_data_size = sizeof(MLPParseContext),

    .parser_init    = mlp_init,

    .parser_parse   = mlp_parse,

    .parser_close   = ff_parse_close,

};