1 files changed, 81 insertions, 0 deletions
diff --git a/libs/evoral/evoral/TimeConverter.h b/libs/evoral/evoral/TimeConverter.h
new file mode 100644
index 0000000000..b0ef750f28
--- /dev/null
+++ b/libs/evoral/evoral/TimeConverter.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2009-2014 David Robillard <d@drobilla.net>
+ * Copyright (C) 2010-2012 Carl Hetherington <carl@carlh.net>
+ * Copyright (C) 2011-2014 Paul Davis <paul@linuxaudiosystems.com>
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef EVORAL_TIME_CONVERTER_HPP
+#define EVORAL_TIME_CONVERTER_HPP
+
+#include "evoral/visibility.h"
+
+namespace Evoral {
+
+/** A bidirectional converter between two different time units.
+ *
+ * Think of the conversion method names as if they are written in-between
+ * the two template parameters (i.e. "A <name> B").
+ *
+ * _origin_b should be the origin for conversion in the units of B.
+ * That is, there is some point in time _origin_b, such that:
+ *
+ *    to()   converts a time _origin_b + a into an offset from _origin_b in units of B.
+ *    from() converts a time _origin_b + b into an offset from _origin_b in units of A.
+ */
+template<typename A, typename B>
+class LIBEVORAL_TEMPLATE_API TimeConverter {
+public:
+	TimeConverter () : _origin_b (0) {}
+	TimeConverter (B ob) : _origin_b (ob) {}
+	virtual ~TimeConverter();
+
+	/** Convert A time to B time (A to B) */
+	virtual B to(A a) const = 0;
+
+	/** Convert B time to A time (A from B) */
+	virtual A from(B b) const = 0;
+
+	B origin_b () const {
+		return _origin_b;
+	}
+
+	void set_origin_b (B o) {
+		_origin_b = o;
+	}
+
+protected:
+	B _origin_b;
+};
+
+
+/** A stub TimeConverter that simple statically casts between types.
+ *  _origin_b has no bearing here, as there is no time conversion
+ *  going on.
+ */
+template<typename A, typename B>
+class LIBEVORAL_TEMPLATE_API IdentityConverter : public TimeConverter<A,B> {
+  public:
+	IdentityConverter() {}
+
+	B to(A a)   const;
+	A from(B b) const;
+};
+
+
+} // namespace Evoral
+
+#endif // EVORAL_TIME_CONVERTER_HPP