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/*

 * SSA/ASS demuxer

 * Copyright (c) 2008 Michael Niedermayer

 * Copyright (c) 2014 Clément Bœsch

 *

 * 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 

#include "avformat.h"

#include "internal.h"

#include "subtitles.h"

#include "libavcodec/internal.h"

#include "libavutil/bprint.h"

typedef struct ASSContext {

    FFDemuxSubtitlesQueue q;

    unsigned readorder;

} ASSContext;

static int ass_probe(AVProbeData *p)

{

    char buf[13];

    FFTextReader tr;

    ff_text_init_buf(&tr, p->buf, p->buf_size);

    ff_text_read(&tr, buf, sizeof(buf));

    if (!memcmp(buf, "[Script Info]", 13))

        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_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,

                         int64_t *start, int *duration)

{

    int pos = 0;

    int64_t end;

    int hh1, mm1, ss1, ms1;

    int hh2, mm2, ss2, ms2;

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

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

               &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {

        /* This is not part of the sscanf itself in order to handle an actual

         * number (which would be the Layer) or the form "Marked=N" (which is

         * the old SSA field, now replaced by Layer, and will lead to Layer

         * being 0 here). */

        const int layer = atoi(p + 10);

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

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

        *duration = end - *start;

        av_bprint_clear(dst);

        av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);

        /* right strip the buffer */

        while (dst->len > 0 &&

               dst->str[dst->len - 1] == '\r' ||

               dst->str[dst->len - 1] == '\n')

            dst->str[--dst->len] = 0;

        return 0;

    }

    return -1;

}

static int64_t get_line(AVBPrint *buf, FFTextReader *tr)

{

    int64_t pos = ff_text_pos(tr);

    av_bprint_clear(buf);

    for (;;) {

        char c = ff_text_r8(tr);

        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, rline;

    int res = 0;

    AVStream *st;

    FFTextReader tr;

    ff_text_init_avio(s, &tr, s->pb);

    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_ASS;

    av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);

    av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);

    av_bprint_init(&rline,  0, AV_BPRINT_SIZE_UNLIMITED);

    for (;;) {

        int64_t pos = get_line(&line, &tr);

        int64_t ts_start = AV_NOPTS_VALUE;

        int duration = -1;

        AVPacket *sub;

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

            break;

        if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {

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

            continue;

        }

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

        if (!sub) {

            res = AVERROR(ENOMEM);

            goto end;

        }

        sub->pos = pos;

        sub->pts = ts_start;

        sub->duration = duration;

    }

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

    if (res < 0)

        goto end;

    ff_subtitles_queue_finalize(&ass->q);

end:

    av_bprint_finalize(&header, NULL);

    av_bprint_finalize(&line,   NULL);

    av_bprint_finalize(&rline,  NULL);

    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,

};