1 /* This file is part of Evoral.
2 * Copyright (C) 2009 David Robillard <http://drobilla.net>
3 * Copyright (C) 2009 Paul Davis
5 * Evoral is free software; you can redistribute it and/or modify it under the
6 * terms of the GNU General Public License as published by the Free Software
7 * Foundation; either version 2 of the License, or (at your option) any later
10 * Evoral is distributed in the hope that it will be useful, but WITHOUT ANY
11 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 #ifndef EVORAL_TIME_CONVERTER_HPP
20 #define EVORAL_TIME_CONVERTER_HPP
24 /** A bidirectional converter between two different time units.
26 * Think of the conversion method names as if they are written in-between
27 * the two template parameters (i.e. "A <name> B").
29 * _origin_b should be the origin for conversion in the units of B.
30 * That is, there is some point in time _origin_b, such that:
32 * to() converts a time _origin_b + a into an offset from _origin_b in units of B.
33 * from() converts a time _origin_b + b into an offset from _origin_b in units of A.
35 template<typename A, typename B>
38 TimeConverter () : _origin_b (0) {}
39 TimeConverter (B ob) : _origin_b (ob) {}
40 virtual ~TimeConverter() {}
42 /** Convert A time to B time (A to B) */
43 virtual B to(A a) const = 0;
45 /** Convert B time to A time (A from B) */
46 virtual A from(B b) const = 0;
52 void set_origin_b (B o) {
61 /** A stub TimeConverter that simple statically casts between types.
62 * _origin_b has no bearing here, as there is no time conversion
65 template<typename A, typename B>
66 class IdentityConverter : public TimeConverter<A,B> {
68 IdentityConverter() {}
69 B to(A a) const { return static_cast<B>(a); }
70 A from(B b) const { return static_cast<A>(b); }
76 #endif // EVORAL_TIME_CONVERTER_HPP