mkvtoolnix/r_srt.cpp

/*
  mkvmerge -- utility for splicing together matroska files
      from component media subtypes

  r_srt.cpp

  Written by Moritz Bunkus <moritz@bunkus.org>

  Distributed under the GPL
  see the file COPYING for details
  or visit http://www.gnu.org/copyleft/gpl.html
*/

/*!
    \file
    \version $Id$
    \brief Subripper subtitle reader
    \author Moritz Bunkus <moritz@bunkus.org>
*/

#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include "mkvmerge.h"
#include "pr_generic.h"
#include "r_srt.h"
#include "subtitles.h"
#include "matroska.h"

using namespace std;

#define iscolon(s) (*(s) == ':')
#define iscomma(s) (*(s) == ',')
#define istwodigits(s) (isdigit(*(s)) && isdigit(*(s + 1)))
#define isthreedigits(s) (isdigit(*(s)) && isdigit(*(s + 1)) && \
                          isdigit(*(s + 2)))
#define isarrow(s) (!strncmp((s), " --> ", 5))
#define istimecode(s) (istwodigits(s) && iscolon(s + 2) && \
                        istwodigits(s + 3) && iscolon(s + 5) && \
                        istwodigits(s + 6) && iscomma(s + 8) && \
                        isthreedigits(s + 9))
#define issrttimecode(s) (istimecode(s) && isarrow(s + 12) && \
                           istimecode(s + 17))

int srt_reader_c::probe_file(mm_io_c *mm_io, int64_t size) {
  char chunk[2048];

  try {
    mm_io->setFilePointer(0, seek_beginning);
    if (mm_io->gets(chunk, 2047) == NULL)
      return 0;
    if ((chunk[0] != '1') || ((chunk[1] != '\n') && (chunk[1] != '\r')))
      return 0;
    if (mm_io->gets(chunk, 2047) == NULL)
      return 0;
    if ((strlen(chunk) < 29) ||  !issrttimecode(chunk))
      return 0;
    if (mm_io->gets(chunk, 2047) == NULL)
      return 0;
    mm_io->setFilePointer(0, seek_beginning);
  } catch (exception &ex) {
    return 0;
  }
  return 1;
}

srt_reader_c::srt_reader_c(track_info_t *nti) throw (error_c):
  generic_reader_c(nti) {
  try {
    mm_io = new mm_io_c(ti->fname, MODE_READ);
    if (!srt_reader_c::probe_file(mm_io, 0))
      throw error_c("srt_reader: Source is not a valid SRT file.");
    ti->id = 0;                 // ID for this track.
    textsubs_packetizer = new textsubs_packetizer_c(this, MKV_S_TEXTUTF8, NULL,
                                                    0, ti);
  } catch (exception &ex) {
    throw error_c("srt_reader: Could not open the source file.");
  }
  if (verbose)
    fprintf(stdout, "Using SRT subtitle reader for %s.\n+-> Using "
            "text subtitle output module for subtitles.\n", ti->fname);
}

srt_reader_c::~srt_reader_c() {
  if (textsubs_packetizer != NULL)
    delete textsubs_packetizer;
}

int srt_reader_c::read() {
  int64_t start, end;
  char *subtitles;
  subtitles_c subs;

  while (1) {
    if (mm_io->gets(chunk, 2047) == NULL)
      break;
    if (mm_io->gets(chunk, 2047) == NULL)
      break;
    chunk[2047] = 0;
    if ((strlen(chunk) < 29) ||  !issrttimecode(chunk))
      break;

// 00:00:00,000 --> 00:00:00,000
// 01234567890123456789012345678
//           1         2
    chunk[2] = 0;
    chunk[5] = 0;
    chunk[8] = 0;
    chunk[12] = 0;
    chunk[19] = 0;
    chunk[22] = 0;
    chunk[25] = 0;
    chunk[29] = 0;

    start = atol(chunk) * 3600000 + atol(&chunk[3]) * 60000 +
            atol(&chunk[6]) * 1000 + atol(&chunk[9]);
    end = atol(&chunk[17]) * 3600000 + atol(&chunk[20]) * 60000 +
          atol(&chunk[23]) * 1000 + atol(&chunk[26]);
    subtitles = NULL;
    while (1) {
      if (mm_io->gets(chunk, 2047) == NULL)
        break;
      chunk[2047] = 0;
      if ((*chunk == '\n') || (*chunk == '\r'))
        break;
      if (subtitles == NULL) {
        subtitles = safestrdup(chunk);
      } else {
        subtitles = (char *)saferealloc(subtitles, strlen(chunk) + 1 +
                                        strlen(subtitles));
        strcat(subtitles, chunk);
      }
    }
    if (subtitles != NULL) {
      subs.add(start, end, subtitles);
      safefree(subtitles);
    }
  }

  if ((subs.check() != 0) && verbose)
    fprintf(stdout, "srt_reader: Warning: The subtitle file seems to be "
            "badly broken. The output file might not be playable "
            "correctly.\n");
  subs.process(textsubs_packetizer);

  return 0;
}

packet_t *srt_reader_c::get_packet() {
  return textsubs_packetizer->get_packet();
}

int srt_reader_c::display_priority() {
  return DISPLAYPRIORITY_LOW;
}

static char wchar[] = "-\\|/-\\|/-";

void srt_reader_c::display_progress() {
  fprintf(stdout, "working... %c\r", wchar[act_wchar]);
  act_wchar++;
  if (act_wchar == strlen(wchar))
    act_wchar = 0;
  fflush(stdout);
}

void srt_reader_c::set_headers() {
  textsubs_packetizer->set_headers();
}

void srt_reader_c::identify() {
  fprintf(stdout, "File '%s': container: SRT\nTrack ID 0: subtitles (SRT)\n",
          ti->fname);
}