3120bae8b4
git-svn-id: svn://localhost/ardour2/branches/3.0@11749 d708f5d6-7413-0410-9779-e7cbd77b26cf
77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
/* This file is part of Evoral.
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* Copyright (C) 2009 David Robillard <http://drobilla.net>
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* Copyright (C) 2009 Paul Davis
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*
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* Evoral is free software; you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option) any later
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* version.
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*
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* Evoral is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef EVORAL_TIME_CONVERTER_HPP
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#define EVORAL_TIME_CONVERTER_HPP
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namespace Evoral {
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/** A bidirectional converter between two different time units.
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*
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* Think of the conversion method names as if they are written in-between
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* the two template parameters (i.e. "A <name> B").
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*
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* _origin_b should be the origin for conversion in the units of B.
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* That is, there is some point in time _origin_b, such that:
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*
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* to() converts a time _origin_b + a into an offset from _origin_b in units of B.
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* from() converts a time _origin_b + b into an offset from _origin_b in units of A.
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*/
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template<typename A, typename B>
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class TimeConverter {
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public:
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TimeConverter () : _origin_b (0) {}
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TimeConverter (B ob) : _origin_b (ob) {}
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virtual ~TimeConverter() {}
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/** Convert A time to B time (A to B) */
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virtual B to(A a) const = 0;
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/** Convert B time to A time (A from B) */
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virtual A from(B b) const = 0;
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B origin_b () const {
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return _origin_b;
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}
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void set_origin_b (B o) {
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_origin_b = o;
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}
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protected:
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B _origin_b;
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};
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/** A stub TimeConverter that simple statically casts between types.
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* _origin_b has no bearing here, as there is no time conversion
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* going on.
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*/
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template<typename A, typename B>
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class IdentityConverter : public TimeConverter<A,B> {
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public:
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IdentityConverter() {}
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B to(A a) const { return static_cast<B>(a); }
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A from(B b) const { return static_cast<A>(b); }
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};
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} // namespace Evoral
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#endif // EVORAL_TIME_CONVERTER_HPP
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