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/*
Copyright (C) 2022 Carl Hetherington <cth@carlh.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "exceptions.h"
#include "subrip_reader.h"
#include "util.h"
#include "web_vtt_reader.h"
#include <boost/algorithm/string.hpp>
#include <boost/algorithm/string_regex.hpp>
#include <boost/bind.hpp>
#include <boost/regex.hpp>
#include <iostream>
#include <vector>
using std::function;
using std::string;
using std::vector;
using boost::optional;
using namespace sub;
WebVTTReader::WebVTTReader(FILE* file)
{
this->read(boost::bind(&get_line_file, file));
}
WebVTTReader::WebVTTReader(string subs)
{
this->read(boost::bind(&get_line_string, &subs));
}
void
WebVTTReader::read(std::function<optional<string> ()> get_line)
{
enum class State {
/* expecting WEBVTT */
HEADER,
/* awaiting a NOTE or a subtitle timing line */
DATA,
/* reading the text of a subtitle */
SUBTITLE,
/* reading a note */
NOTE
} state = State::HEADER;
RawSubtitle rs;
rs.vertical_position.line = 0;
rs.vertical_position.reference = TOP_OF_SUBTITLE;
while (true) {
auto line = get_line();
if (!line) {
break;
}
trim_right_if(*line, boost::is_any_of("\n\r"));
remove_unicode_bom(line);
/* Keep some history in case there is an error to report */
_context.push_back(*line);
if (_context.size() > 5) {
_context.pop_front();
}
switch (state) {
case State::HEADER:
if (!boost::starts_with(*line, "WEBVTT")) {
throw WebVTTError("No WEBVTT header found");
}
state = State::DATA;
break;
case State::DATA:
if (boost::starts_with(*line, "NOTE")) {
state = State::NOTE;
} else if (line->find("-->") != string::npos) {
/* Further trim this line, removing spaces from the end */
trim_right_if(*line, boost::is_any_of(" "));
vector<string> parts;
boost::algorithm::split(parts, *line, boost::algorithm::is_any_of(" "), boost::token_compress_on);
if (parts.size() != 3 && parts.size() != 7) {
for (int i = 0; i < 2; ++i) {
auto ex = get_line();
if (ex) {
_context.push_back(*ex);
}
}
throw WebVTTError(*line, "a time line", _context);
}
string expected;
auto from = SubripReader::convert_time(parts[0], &expected);
if (!from) {
throw WebVTTError(parts[0], expected, _context);
}
rs.from = *from;
auto to = SubripReader::convert_time(parts[2], &expected);
if (!to) {
throw WebVTTError(parts[2], expected, _context);
}
rs.to = *to;
rs.vertical_position.line = 0;
state = State::SUBTITLE;
} else if (!line->empty()) {
throw WebVTTError(*line, "a note or time", _context);
}
break;
case State::SUBTITLE:
if (line->empty()) {
state = State::DATA;
} else {
/* Split up this line on unicode "LINE SEPARATOR". This feels hacky but also
* the least unpleasant place to do it.
*/
vector<string> sub_lines;
boost::algorithm::split_regex(sub_lines, *line, boost::regex("\xe2\x80\xa8"));
for (auto sub_line: sub_lines) {
rs.text = sub_line;
_subs.push_back(rs);
rs.vertical_position.line = rs.vertical_position.line.get() + 1;
}
}
break;
case State::NOTE:
if (line->empty()) {
state = State::DATA;
}
break;
}
}
}
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