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| -rw-r--r-- | src/Chrono.hxx | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/Chrono.hxx b/src/Chrono.hxx new file mode 100644 index 000000000..cc87c5ba1 --- /dev/null +++ b/src/Chrono.hxx @@ -0,0 +1,226 @@ +/* + * Copyright (C) 2003-2014 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 MPD_CHRONO_HXX +#define MPD_CHRONO_HXX + +#include "Compiler.h" + +#include <chrono> +#include <utility> +#include <cstdint> + +#if defined(__GNUC__) && !GCC_CHECK_VERSION(4,7) && !defined(__clang__) +/* std::chrono::duration operators are "constexpr" since gcc 4.7 */ +#define chrono_constexpr gcc_pure +#else +#define chrono_constexpr constexpr +#endif + +/** + * A time stamp within a song. Granularity is 1 millisecond and the + * maximum value is about 49 days. + */ +class SongTime : public std::chrono::duration<std::uint32_t, std::milli> { + typedef std::chrono::duration<std::uint32_t, std::milli> Base; + typedef Base::rep rep; + +public: + SongTime() = default; + + template<typename T> + explicit constexpr SongTime(T t):Base(t) {} + + static constexpr SongTime zero() { + return SongTime(Base::zero()); + } + + static constexpr SongTime FromS(unsigned s) { + return SongTime(rep(s) * 1000); + } + + static constexpr SongTime FromS(float s) { + return SongTime(rep(s * 1000)); + } + + static constexpr SongTime FromS(double s) { + return SongTime(rep(s * 1000)); + } + + static constexpr SongTime FromMS(rep ms) { + return SongTime(ms); + } + + constexpr rep ToS() const { + return count() / rep(1000); + } + + constexpr rep RoundS() const { + return (count() + 500) / rep(1000); + } + + constexpr rep ToMS() const { + return count(); + } + + template<typename T=rep> + constexpr T ToScale(unsigned scale) const { + return count() * T(scale) / 1000; + } + + /** + * Convert a scalar value with the given scale to a #SongTime + * instance. + * + * @param value the input value + * @param scale the value's scale in Hz + */ + template<typename T=rep> + static constexpr SongTime FromScale(T value, unsigned scale) { + return SongTime(value * T(1000) / T(scale)); + } + + constexpr double ToDoubleS() const { + return double(count()) / 1000.; + }; + + constexpr bool IsZero() const { + return count() == 0; + } + + constexpr bool IsPositive() const { + return count() > 0; + } + + chrono_constexpr SongTime operator+(const SongTime &other) const { + return SongTime(*(const Base *)this + (const Base &)other); + } + + chrono_constexpr SongTime operator-(const SongTime &other) const { + return SongTime(*(const Base *)this - (const Base &)other); + } +}; + +/** + * A variant of #SongTime that is based on a signed integer. It can + * be used for relative values. + */ +class SignedSongTime : public std::chrono::duration<std::int32_t, std::milli> { + typedef std::chrono::duration<std::int32_t, std::milli> Base; + typedef Base::rep rep; + +public: + SignedSongTime() = default; + + template<typename T> + explicit constexpr SignedSongTime(T t):Base(t) {} + + /** + * Allow implicit conversion from SongTime to SignedSongTime. + */ + constexpr SignedSongTime(SongTime t):Base(t) {} + + static constexpr SignedSongTime zero() { + return SignedSongTime(Base::zero()); + } + + /** + * Generate a negative value. + */ + static constexpr SignedSongTime Negative() { + return SignedSongTime(-1); + } + + static constexpr SignedSongTime FromS(int s) { + return SignedSongTime(rep(s) * 1000); + } + + static constexpr SignedSongTime FromS(unsigned s) { + return SignedSongTime(rep(s) * 1000); + } + + static constexpr SignedSongTime FromS(float s) { + return SignedSongTime(rep(s * 1000)); + } + + static constexpr SignedSongTime FromS(double s) { + return SignedSongTime(rep(s * 1000)); + } + + static constexpr SignedSongTime FromMS(rep ms) { + return SignedSongTime(ms); + } + + constexpr rep ToS() const { + return count() / rep(1000); + } + + constexpr rep RoundS() const { + return (count() + 500) / rep(1000); + } + + constexpr rep ToMS() const { + return count(); + } + + template<typename T=rep> + constexpr T ToScale(unsigned scale) const { + return count() * T(scale) / 1000; + } + + /** + * Convert a scalar value with the given scale to a + * #SignedSongTime instance. + * + * @param value the input value + * @param scale the value's scale in Hz + */ + template<typename T=rep> + static constexpr SignedSongTime FromScale(T value, unsigned scale) { + return SignedSongTime(value * T(1000) / T(scale)); + } + + constexpr double ToDoubleS() const { + return double(count()) / 1000.; + }; + + constexpr bool IsZero() const { + return count() == 0; + } + + constexpr bool IsPositive() const { + return count() > 0; + } + + constexpr bool IsNegative() const { + return count() < 0; + } + + chrono_constexpr SignedSongTime operator+(const SignedSongTime &other) const { + return SignedSongTime(*(const Base *)this + (const Base &)other); + } + + chrono_constexpr SignedSongTime operator-(const SignedSongTime &other) const { + return SignedSongTime(*(const Base *)this - (const Base &)other); + } +}; + +#undef chrono_constexpr + +#endif |