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/* This file is part of Evoral.
* Copyright (C) 2009 David Robillard <http://drobilla.net>
* Copyright (C) 2009 Paul Davis
*
* Evoral 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.
*
* Evoral 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 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 St, 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
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