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/*

 * SSA/ASS demuxer

 * Copyright (c) 2008 Michael Niedermayer

 *

 * 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 "internal.h"

#include "subtitles.h"

#include "libavcodec/internal.h"

#include "libavutil/bprint.h"

typedef struct ASSContext{

    FFDemuxSubtitlesQueue q;

}ASSContext;

static int ass_probe(AVProbeData *p)

{

    const char *header= "[Script Info]";

    if(   !memcmp(p->buf  , header, strlen(header))

       || !memcmp(p->buf+3, header, strlen(header)))

        return AVPROBE_SCORE_MAX;

    return 0;

}

static int ass_read_close(AVFormatContext *s)

{

    ASSContext *ass = s->priv_data;

    ff_subtitles_queue_clean(&ass->q);

    return 0;

}

static int read_ts(const uint8_t *p, int64_t *start, int *duration)

{

    int64_t end;

    int hh1, mm1, ss1, ms1;

    int hh2, mm2, ss2, ms2;

    if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",

               &hh1, &mm1, &ss1, &ms1,

               &hh2, &mm2, &ss2, &ms2) == 8) {

        end    = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;

        *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;

        *duration = end - *start;

        return 0;

    }

    return -1;

}

static int64_t get_line(AVBPrint *buf, AVIOContext *pb)

{

    int64_t pos = avio_tell(pb);

    av_bprint_clear(buf);

    for (;;) {

        char c = avio_r8(pb);

        if (!c)

            break;

        av_bprint_chars(buf, c, 1);

        if (c == '\n')

            break;

    }

    return pos;

}

static int ass_read_header(AVFormatContext *s)

{

    ASSContext *ass = s->priv_data;

    AVBPrint header, line;

    int header_remaining, res = 0;

    AVStream *st;

    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    avpriv_set_pts_info(st, 64, 1, 100);

    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

    st->codec->codec_id= AV_CODEC_ID_SSA;

    header_remaining= INT_MAX;

    av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);

    av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);

    for (;;) {

        int64_t pos = get_line(&line, s->pb);

        if (!line.str[0]) // EOF

            break;

        if (!memcmp(line.str, "[Events]", 8))

            header_remaining= 2;

        else if (line.str[0]=='[')

            header_remaining= INT_MAX;

        if (header_remaining) {

            av_bprintf(&header, "%s", line.str);

            header_remaining--;

        } else {

            int64_t ts_start = AV_NOPTS_VALUE;

            int duration = -1;

            AVPacket *sub;

            if (read_ts(line.str, &ts_start, &duration) < 0)

                continue;

            sub = ff_subtitles_queue_insert(&ass->q, line.str, line.len, 0);

            if (!sub) {

                res = AVERROR(ENOMEM);

                goto end;

            }

            sub->pos = pos;

            sub->pts = ts_start;

            sub->duration = duration;

        }

    }

    av_bprint_finalize(&line, NULL);

    res = avpriv_bprint_to_extradata(st->codec, &header);

    if (res < 0)

        goto end;

    ff_subtitles_queue_finalize(&ass->q);

end:

    return res;

}

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

{

    ASSContext *ass = s->priv_data;

    return ff_subtitles_queue_read_packet(&ass->q, pkt);

}

static int ass_read_seek(AVFormatContext *s, int stream_index,

                         int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

{

    ASSContext *ass = s->priv_data;

    return ff_subtitles_queue_seek(&ass->q, s, stream_index,

                                   min_ts, ts, max_ts, flags);

}

AVInputFormat ff_ass_demuxer = {

    .name           = "ass",

    .long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),

    .priv_data_size = sizeof(ASSContext),

    .read_probe     = ass_probe,

    .read_header    = ass_read_header,

    .read_packet    = ass_read_packet,

    .read_close     = ass_read_close,

    .read_seek2     = ass_read_seek,

};