/*

 * Raw FLAC demuxer

 * Copyright (c) 2001 Fabrice Bellard

 *

 * 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/channel_layout.h"

#include "libavutil/mem.h"

#include "libavcodec/avcodec.h"

#include "libavcodec/bytestream.h"

#include "libavcodec/flac.h"

#include "avformat.h"

#include "avio_internal.h"

#include "demux.h"

#include "flac_picture.h"

#include "internal.h"

#include "rawdec.h"

#include "oggdec.h"

#include "replaygain.h"

#define SEEKPOINT_SIZE 18

typedef struct FLACDecContext {

    FFRawDemuxerContext rawctx;

    int found_seektable;

    AVCodecContext *parser_dec;

} FLACDecContext;

static void reset_index_position(int64_t metadata_head_size, AVStream *st)

{

    FFStream *const sti = ffstream(st);

    /* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */

    for (int i = 0; i < sti->nb_index_entries; i++)

        sti->index_entries[i].pos += metadata_head_size;

}

static const uint16_t sr_table[16] = {

    0, 1764, 3528, 3840, 160, 320, 441, 480, 640, 882, 960, 1920, 0, 0, 0, 0

};

static int flac_read_header(AVFormatContext *s)

{

    int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;

    uint8_t header[4];

    uint8_t *buffer=NULL;

    uint32_t marker;

    FLACDecContext *flac = s->priv_data;

    AVStream *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_FLAC;

    ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL_RAW;

    /* the parameters will be extracted from the compressed bitstream */

    /* if fLaC marker is not found, assume there is no header */

    marker = avio_rl32(s->pb);

    if (marker != MKTAG('f','L','a','C')) {

        const int sample_rate = 50 * sr_table[(marker >> 16) & 0xF];

        if (sample_rate)

            avpriv_set_pts_info(st, 64, 1, sample_rate);

        avio_seek(s->pb, -4, SEEK_CUR);

        return 0;

    }

    /* process metadata blocks */

    while (!avio_feof(s->pb) && !metadata_last) {

        ret = avio_read(s->pb, header, 4);

        if (ret < 0) {

            return ret;

        } else if (ret != 4) {

            return AVERROR_EOF;

        }

        flac_parse_block_header(header, &metadata_last, &metadata_type,

                                   &metadata_size);

        switch (metadata_type) {

        /* allocate and read metadata block for supported types */

        case FLAC_METADATA_TYPE_STREAMINFO:

        case FLAC_METADATA_TYPE_CUESHEET:

        case FLAC_METADATA_TYPE_PICTURE:

        case FLAC_METADATA_TYPE_VORBIS_COMMENT:

        case FLAC_METADATA_TYPE_SEEKTABLE:

            buffer = av_mallocz(metadata_size + AV_INPUT_BUFFER_PADDING_SIZE);

            if (!buffer) {

                return AVERROR(ENOMEM);

            }

            ret = ffio_read_size(s->pb, buffer, metadata_size);

            if (ret < 0)

                goto fail;

            break;

        /* skip metadata block for unsupported types */

        default:

            ret = avio_skip(s->pb, metadata_size);

            if (ret < 0)

                return ret;

        }

        if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {

            uint32_t samplerate;

            uint64_t samples;

            /* STREAMINFO can only occur once */

            if (found_streaminfo) {

                RETURN_ERROR(AVERROR_INVALIDDATA);

            }

            if (metadata_size != FLAC_STREAMINFO_SIZE) {

                RETURN_ERROR(AVERROR_INVALIDDATA);

            }

            found_streaminfo = 1;

            st->codecpar->extradata      = buffer;

            st->codecpar->extradata_size = metadata_size;

            buffer = NULL;

            /* get sample rate and sample count from STREAMINFO header;

             * other parameters will be extracted by the parser */

            samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;

            samples    = (AV_RB64(st->codecpar->extradata + 13) >> 24) & ((1ULL << 36) - 1);

            /* set time base and duration */

            if (samplerate > 0) {

                avpriv_set_pts_info(st, 64, 1, samplerate);

                if (samples > 0)

                    st->duration = samples;

            }

        } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {

            uint8_t isrc[13];

            uint64_t start;

            const uint8_t *offset;

            int i, chapters, track, ti;

            if (metadata_size < 431)

                RETURN_ERROR(AVERROR_INVALIDDATA);

            offset = buffer + 395;

            chapters = bytestream_get_byte(&offset) - 1;

            if (chapters <= 0)

                RETURN_ERROR(AVERROR_INVALIDDATA);

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

                if (offset + 36 - buffer > metadata_size)

                    RETURN_ERROR(AVERROR_INVALIDDATA);

                start = bytestream_get_be64(&offset);

                track = bytestream_get_byte(&offset);

                bytestream_get_buffer(&offset, isrc, 12);

                isrc[12] = 0;

                offset += 14;

                ti = bytestream_get_byte(&offset);

                if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);

                offset += ti * 12;

                avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);

            }

            av_freep(&buffer);

        } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {

            ret = ff_flac_parse_picture(s, &buffer, metadata_size, 1);

            av_freep(&buffer);

            if (ret < 0) {

                av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");

                return ret;

            }

        } else if (metadata_type == FLAC_METADATA_TYPE_SEEKTABLE) {

            const uint8_t *seekpoint = buffer;

            int i, seek_point_count = metadata_size/SEEKPOINT_SIZE;

            flac->found_seektable = 1;

            if ((s->flags&AVFMT_FLAG_FAST_SEEK)) {

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

                    int64_t timestamp = bytestream_get_be64(&seekpoint);

                    int64_t pos = bytestream_get_be64(&seekpoint);

                    /* skip number of samples */

                    bytestream_get_be16(&seekpoint);

                    av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);

                }

            }

            av_freep(&buffer);

        }

        else {

            /* STREAMINFO must be the first block */

            if (!found_streaminfo) {

                RETURN_ERROR(AVERROR_INVALIDDATA);

            }

            /* process supported blocks other than STREAMINFO */

            if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {

                AVDictionaryEntry *chmask;

                ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);

                if (ret < 0) {

                    av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");

                } else if (ret > 0) {

                    s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;

                }

                /* parse the channels mask if present */

                chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);

                if (chmask) {

                    uint64_t mask = strtol(chmask->value, NULL, 0);

                    if (!mask || mask & ~0x3ffffULL) {

                        av_log(s, AV_LOG_WARNING,

                               "Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");

                    } else {

                        av_channel_layout_from_mask(&st->codecpar->ch_layout, mask);

                        av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);

                    }

                }

            }

            av_freep(&buffer);

        }

    }

    ret = ff_replaygain_export(st, s->metadata);

    if (ret < 0)

        return ret;

    reset_index_position(avio_tell(s->pb), st);

    return 0;

fail:

    av_free(buffer);

    return ret;

}

static int raw_flac_probe(const AVProbeData *p)

{

    if ((p->buf[2] & 0xF0) == 0)    // blocksize code invalid

        return 0;

    if ((p->buf[2] & 0x0F) == 0x0F) // sample rate code invalid

        return 0;

    if ((p->buf[3] & 0xF0) >= FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE << 4)

        // channel mode invalid

        return 0;

    if ((p->buf[3] & 0x06) == 0x06) // bits per sample code invalid

        return 0;

    if ((p->buf[3] & 0x01) == 0x01) // reserved bit set

        return 0;

    return AVPROBE_SCORE_EXTENSION / 4 + 1;

}

static int flac_probe(const AVProbeData *p)

{

    if ((AV_RB16(p->buf) & 0xFFFE) == 0xFFF8)

        return raw_flac_probe(p);

    /* file header + metadata header + checked bytes of streaminfo */

    if (p->buf_size >= 4 + 4 + 13) {

        int type           = p->buf[4] & 0x7f;

        int size           = AV_RB24(p->buf + 5);

        int min_block_size = AV_RB16(p->buf + 8);

        int max_block_size = AV_RB16(p->buf + 10);

        int sample_rate    = AV_RB24(p->buf + 18) >> 4;

        if (memcmp(p->buf, "fLaC", 4))

            return 0;

        if (type == FLAC_METADATA_TYPE_STREAMINFO &&

            size == FLAC_STREAMINFO_SIZE          &&

            min_block_size >= 16                  &&

            max_block_size >= min_block_size      &&

            sample_rate && sample_rate <= 655350)

            return AVPROBE_SCORE_MAX;

        return AVPROBE_SCORE_EXTENSION;

    }

    return 0;

}

av_unused static int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,

                                             int64_t *ppos, int64_t pos_limit)

{

    FLACDecContext *flac = s->priv_data;

    FFFormatContext *const si = ffformatcontext(s);

    AVPacket *const pkt = si->parse_pkt;

    AVStream *st = s->streams[stream_index];

    AVCodecParserContext *parser;

    int ret;

    int64_t pts = AV_NOPTS_VALUE;

    if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)

        return AV_NOPTS_VALUE;

    if (!flac->parser_dec) {

        flac->parser_dec = avcodec_alloc_context3(NULL);

        if (!flac->parser_dec)

            return AV_NOPTS_VALUE;

        ret = avcodec_parameters_to_context(flac->parser_dec, st->codecpar);

        if (ret < 0)

            return ret;

    }

    parser = av_parser_init(st->codecpar->codec_id);

    if (!parser)

        return AV_NOPTS_VALUE;

    parser->flags |= PARSER_FLAG_USE_CODEC_TS;

    for (;;){

        uint8_t *data;

        int size;

        ret = ff_raw_read_partial_packet(s, pkt);

        if (ret < 0){

            if (ret == AVERROR(EAGAIN))

                continue;

            else {

                av_packet_unref(pkt);

                av_assert1(!pkt->size);

            }

        }

        av_parser_parse2(parser, flac->parser_dec,

                         &data, &size, pkt->data, pkt->size,

                         pkt->pts, pkt->dts, *ppos);

        av_packet_unref(pkt);

        if (size) {

            if (parser->pts != AV_NOPTS_VALUE){

                // seeking may not have started from beginning of a frame

                // calculate frame start position from next frame backwards

                *ppos = parser->next_frame_offset - size;

                pts = parser->pts;

                break;

            }

        } else if (ret < 0)

            break;

    }

    av_parser_close(parser);

    return pts;

}

static int flac_close(AVFormatContext *s)

{

    FLACDecContext *flac = s->priv_data;

    avcodec_free_context(&flac->parser_dec);

    return 0;

}

static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {

    AVStream *const st  = s->streams[0];

    FFStream *const sti = ffstream(st);

    int index;

    int64_t pos;

    AVIndexEntry e;

    FLACDecContext *flac = s->priv_data;

    if (!flac->found_seektable || !(s->flags&AVFMT_FLAG_FAST_SEEK)) {

        return -1;

    }

    index = av_index_search_timestamp(st, timestamp, flags);

    if (index < 0 || index >= sti->nb_index_entries)

        return -1;

    e   = sti->index_entries[index];

    pos = avio_seek(s->pb, e.pos, SEEK_SET);

    if (pos >= 0) {

        return 0;

    }

    return -1;

}

const FFInputFormat ff_flac_demuxer = {

    .p.name         = "flac",

    .p.long_name    = NULL_IF_CONFIG_SMALL("raw FLAC"),

    .p.flags        = AVFMT_GENERIC_INDEX,

    .p.extensions   = "flac",

    .p.priv_class   = &ff_raw_demuxer_class,

    .read_probe     = flac_probe,

    .read_header    = flac_read_header,

    .read_close     = flac_close,

    .read_packet    = ff_raw_read_partial_packet,

    .read_seek      = flac_seek,

    .read_timestamp = flac_read_timestamp,

    .raw_codec_id   = AV_CODEC_ID_FLAC,

    .priv_data_size = sizeof(FLACDecContext),

    .flags_internal = FF_INFMT_FLAG_ID3V2_AUTO,

};