Add very basic subrip writer.

5 files changed, 230 insertions, 0 deletions

diff --git a/src/subrip_writer.cc b/src/subrip_writer.cc
new file mode 100644
index 0000000..80602d0
--- /dev/null
+++ b/src/subrip_writer.cc
@@ -0,0 +1,76 @@
+/*
+    Copyright (C) 2026 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 "subrip_writer.h"
+#include "subtitle.h"
+#include <fmt/format.h>
+#include <fstream>
+
+
+using std::string;
+using std::vector;
+using namespace sub;
+
+
+static string
+time_to_subrip_string(Time t)
+{
+	return fmt::format("{:02d}:{:02d}:{:02d},{:03d}", t.hours(), t.minutes(), t.seconds(), t.milliseconds());
+}
+
+
+static string
+wrap_with_tags(string text, bool bold, bool italic, bool underline)
+{
+	if (bold) {
+		text = "<b>" + text + "</b>";
+	}
+	if (italic) {
+		text = "<i>" + text + "</i>";
+	}
+	if (underline) {
+		text = "<u>" + text + "</u>";
+	}
+	return text;
+}
+
+
+void
+sub::write_subrip(vector<Subtitle> const& subtitles, boost::filesystem::path file_name)
+{
+	std::ofstream f(file_name.string());
+
+	int index = 1;
+	for (auto const& sub: subtitles) {
+		f << index << "\n";
+		f << time_to_subrip_string(sub.from) << " --> " << time_to_subrip_string(sub.to) << "\n";
+
+		for (auto const& line: sub.lines) {
+			for (auto const& block: line.blocks) {
+				f << wrap_with_tags(block.text, block.bold, block.italic, block.underline);
+			}
+			f << "\n";
+		}
+		f << "\n";
+		++index;
+	}
+
+	f.close();
+}
diff --git a/src/subrip_writer.h b/src/subrip_writer.h
new file mode 100644
index 0000000..b6d41ad
--- /dev/null
+++ b/src/subrip_writer.h
@@ -0,0 +1,44 @@
+/*
+    Copyright (C) 2026 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.
+
+*/
+
+
+#ifndef LIBSUB_SUBRIP_WRITER_H
+#define LIBSUB_SUBRIP_WRITER_H
+
+
+#include <string>
+#include <vector>
+#include <boost/filesystem.hpp>
+
+
+namespace sub {
+
+
+class Subtitle;
+
+
+extern void write_subrip(
+	std::vector<Subtitle> const& subtitles,
+	boost::filesystem::path file_name
+	);
+
+
+}
+
+#endif
diff --git a/src/wscript b/src/wscript
index 8ae7788..2eee532 100644
--- a/src/wscript
+++ b/src/wscript
@@ -32,6 +32,7 @@ def build(bld):
                  stl_util.cc
                  sub_time.cc
                  subrip_reader.cc
+                 subrip_writer.cc
                  subtitle.cc
                  util.cc
                  vertical_reference.cc
@@ -58,6 +59,7 @@ def build(bld):
               stl_text_reader.h
               sub_time.h
               subrip_reader.h
+              subrip_writer.h
               subtitle.h
               vertical_position.h
               vertical_reference.h
diff --git a/test/subrip_writer_test.cc b/test/subrip_writer_test.cc
new file mode 100644
index 0000000..431b959
--- /dev/null
+++ b/test/subrip_writer_test.cc
@@ -0,0 +1,107 @@
+/*
+    Copyright (C) 2026 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 "subrip_writer.h"
+#include "subtitle.h"
+#include <boost/test/unit_test.hpp>
+#include <fstream>
+
+
+using std::vector;
+using std::string;
+using std::ifstream;
+using std::getline;
+
+
+/** Test writing of a SubRip file */
+BOOST_AUTO_TEST_CASE(subrip_writer_test)
+{
+	vector<sub::Subtitle> subs;
+
+	{
+		sub::Subtitle s;
+		s.from = sub::Time::from_hms(0, 0, 41, 90);
+		s.to = sub::Time::from_hms(0, 0, 42, 210);
+
+		{
+			sub::Block b;
+			b.text = "This is a subtitle";
+			sub::Line l;
+			l.blocks.push_back(b);
+			s.lines.push_back(l);
+		}
+
+		{
+			sub::Block b;
+			b.text = "and that's a line break";
+			sub::Line l;
+			l.blocks.push_back(b);
+			s.lines.push_back(l);
+		}
+
+		subs.push_back(s);
+	}
+
+	{
+		sub::Subtitle s;
+		s.from = sub::Time::from_hms(0, 1, 1, 10);
+		s.to = sub::Time::from_hms(0, 1, 2, 100);
+
+		sub::Line l;
+
+		sub::Block b;
+		b.text = "This is some ";
+		l.blocks.push_back(b);
+
+		b.text = "bold";
+		b.bold = true;
+		l.blocks.push_back(b);
+
+		b.text = " and some ";
+		b.bold = false;
+		l.blocks.push_back(b);
+
+		b.text = "underlined";
+		b.underline = true;
+		l.blocks.push_back(b);
+
+		s.lines.push_back(l);
+		subs.push_back(s);
+	}
+
+	sub::write_subrip(subs, "build/test/test_subrip_writer.srt");
+
+	ifstream f("build/test/test_subrip_writer.srt");
+	string line;
+	vector<string> lines;
+	while (getline(f, line)) {
+		lines.push_back(line);
+	}
+	f.close();
+
+	BOOST_CHECK_EQUAL(lines[0], "1");
+	BOOST_CHECK_EQUAL(lines[1], "00:00:41,090 --> 00:00:42,210");
+	BOOST_CHECK_EQUAL(lines[2], "This is a subtitle");
+	BOOST_CHECK_EQUAL(lines[3], "and that's a line break");
+	BOOST_CHECK_EQUAL(lines[4], "");
+
+	BOOST_CHECK_EQUAL(lines[5], "2");
+	BOOST_CHECK_EQUAL(lines[6], "00:01:01,010 --> 00:01:02,100");
+	BOOST_CHECK_EQUAL(lines[7], "This is some <b>bold</b> <u>underlined</u>");
+}
diff --git a/test/wscript b/test/wscript
index c6a01b0..20ff1d5 100644
--- a/test/wscript
+++ b/test/wscript
@@ -26,6 +26,7 @@ def build(bld):
                  stl_binary_writer_test.cc
                  stl_text_reader_test.cc
                  subrip_reader_test.cc
+                 subrip_writer_test.cc
                  time_test.cc
                  test.cc
                  vertical_position_test.cc