text: /*
   * SubRip 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 "subtitles.h"
  #include "libavutil/bprint.h"
  #include "libavutil/intreadwrite.h"
  
  typedef struct {
      FFDemuxSubtitlesQueue q;
  } SRTContext;
  
  static int srt_probe(AVProbeData *p)
  {
      int v;
      char buf[64], *pbuf;
      FFTextReader tr;
  
      ff_text_init_buf(&tr, p->buf, p->buf_size);
  
      while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
          ff_text_r8(&tr);
  
      /* Check if the first non-empty line is a number. We do not check what the
       * number is because in practice it can be anything. */
      if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0 ||
          strtol(buf, &pbuf, 10) < 0 || *pbuf)
          return 0;
  
      /* Check if the next line matches a SRT timestamp */
      if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0)
          return 0;
      if (buf[0] >= '0' && buf[1] <= '9' && strstr(buf, " --> ")
          && sscanf(buf, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
          return AVPROBE_SCORE_MAX;
  
      return 0;
  }
  
  static int64_t get_pts(const char **buf, int *duration,
                         int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
  {
      int i;
  
      for (i=0; i<2; i++) {
          int hh1, mm1, ss1, ms1;
          int hh2, mm2, ss2, ms2;
          if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
                     "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
                     &hh1, &mm1, &ss1, &ms1,
                     &hh2, &mm2, &ss2, &ms2,
                     x1, x2, y1, y2) >= 8) {
              int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
              int64_t end   = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
              *duration = end - start;
              *buf += ff_subtitles_next_line(*buf);
              return start;
          }
          *buf += ff_subtitles_next_line(*buf);
      }
      return AV_NOPTS_VALUE;
  }
  
  static int srt_read_header(AVFormatContext *s)
  {
      SRTContext *srt = s->priv_data;
      AVBPrint buf;
      AVStream *st = avformat_new_stream(s, NULL);
      int res = 0;
      FFTextReader tr;
      ff_text_init_avio(s, &tr, s->pb);
  
      if (!st)
          return AVERROR(ENOMEM);
      avpriv_set_pts_info(st, 64, 1, 1000);
      st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
      st->codec->codec_id   = AV_CODEC_ID_SUBRIP;
  
      av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
  
      while (!ff_text_eof(&tr)) {
          ff_subtitles_read_text_chunk(&tr, &buf);
  
          if (buf.len) {
              int64_t pos = ff_text_pos(&tr);
              int64_t pts;
              int duration;
              const char *ptr = buf.str;
              int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
              AVPacket *sub;
  
              pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
              if (pts != AV_NOPTS_VALUE) {
                  int len = buf.len - (ptr - buf.str);
                  if (len <= 0)
                      continue;
                  sub = ff_subtitles_queue_insert(&srt->q, ptr, len, 0);
                  if (!sub) {
                      res = AVERROR(ENOMEM);
                      goto end;
                  }
                  sub->pos = pos;
                  sub->pts = pts;
                  sub->duration = duration;
                  if (x1 != -1) {
                      uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
                      if (p) {
                          AV_WL32(p,      x1);
                          AV_WL32(p +  4, y1);
                          AV_WL32(p +  8, x2);
                          AV_WL32(p + 12, y2);
                      }
                  }
              }
          }
      }
  
      ff_subtitles_queue_finalize(&srt->q);
  
  end:
      av_bprint_finalize(&buf, NULL);
      return res;
  }
  
  static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      SRTContext *srt = s->priv_data;
      return ff_subtitles_queue_read_packet(&srt->q, pkt);
  }
  
  static int srt_read_seek(AVFormatContext *s, int stream_index,
                           int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
  {
      SRTContext *srt = s->priv_data;
      return ff_subtitles_queue_seek(&srt->q, s, stream_index,
                                     min_ts, ts, max_ts, flags);
  }
  
  static int srt_read_close(AVFormatContext *s)
  {
      SRTContext *srt = s->priv_data;
      ff_subtitles_queue_clean(&srt->q);
      return 0;
  }
  
  AVInputFormat ff_srt_demuxer = {
      .name        = "srt",
      .long_name   = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
      .priv_data_size = sizeof(SRTContext),
      .read_probe  = srt_probe,
      .read_header = srt_read_header,
      .read_packet = srt_read_packet,
      .read_seek2  = srt_read_seek,
      .read_close  = srt_read_close,
  };
  