/*
  * MicroDVD subtitle demuxer
  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
  *
  * 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 "libavutil/intreadwrite.h"
 
 #define MAX_LINESIZE 2048
 
 
 typedef struct {
     uint8_t lines[3][MAX_LINESIZE];
     int64_t pos[3];
 } MicroDVDContext;
 
 
 static int microdvd_probe(AVProbeData *p)
 {
     unsigned char c, *ptr = p->buf;
     int i;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3;  /* skip UTF-8 BOM */
 
     for (i=0; i<3; i++) {
         if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
             sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
             sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
             return 0;
         ptr += strcspn(ptr, "\n") + 1;
     }
     return AVPROBE_SCORE_MAX;
 }
 
 static int microdvd_read_header(AVFormatContext *s, AVFormatParameters *ap)
 {
     AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */
     MicroDVDContext *microdvd = s->priv_data;
     AVStream *st = av_new_stream(s, 0);
     int i, frame;
     double fps;
     char c;
 
     if (!st)
         return -1;
     for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
         microdvd->pos[i] = avio_tell(s->pb);
         ff_get_line(s->pb, microdvd->lines[i], sizeof(microdvd->lines[i]));
         if ((sscanf(microdvd->lines[i], "{%d}{}%6lf",    &frame, &fps) == 2 ||
              sscanf(microdvd->lines[i], "{%d}{%*d}%6lf", &frame, &fps) == 2)
             && frame <= 1 && fps > 3 && fps < 100)
             pts_info = av_d2q(fps, 100000);
         if (sscanf(microdvd->lines[i], "{DEFAULT}{}%c", &c) == 1) {
             st->codec->extradata = av_strdup(microdvd->lines[i] + 11);
             st->codec->extradata_size = strlen(st->codec->extradata);
             i--;
         }
     }
     av_set_pts_info(st, 64, pts_info.den, pts_info.num);
     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
     st->codec->codec_id   = CODEC_ID_MICRODVD;
     return 0;
 }
 
 static int64_t get_pts(const char *buf)
 {
     int frame;
     char c;
 
     if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
         return frame;
     return AV_NOPTS_VALUE;
 }
 
 static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MicroDVDContext *microdvd = s->priv_data;
     char buffer[MAX_LINESIZE];
     int64_t pos = avio_tell(s->pb);
     int i, len = 0, res = AVERROR_EOF;
 
     for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
         if (microdvd->lines[i][0]) {
             strcpy(buffer, microdvd->lines[i]);
             pos = microdvd->pos[i];
             len = strlen(buffer);
             microdvd->lines[i][0] = 0;
             break;
         }
     }
     if (!len)
         len = ff_get_line(s->pb, buffer, sizeof(buffer));
 
     if (buffer[0] && !(res = av_new_packet(pkt, len))) {
         memcpy(pkt->data, buffer, len);
         pkt->flags |= AV_PKT_FLAG_KEY;
         pkt->pos = pos;
         pkt->pts = pkt->dts = get_pts(buffer);
     }
     return res;
 }
 
 AVInputFormat ff_microdvd_demuxer = {
     .name           = "microdvd",
     .long_name      = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
     .priv_data_size = sizeof(MicroDVDContext),
     .read_probe     = microdvd_probe,
     .read_header    = microdvd_read_header,
     .read_packet    = microdvd_read_packet,
     .flags          = AVFMT_GENERIC_INDEX,
 };