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◆ main openmsx / src / EmuTime.hh
2.2 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef EMUTIME_HH
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#define EMUTIME_HH
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#include "EmuDuration.hh"
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#include "serialize.hh"
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#include <cassert>
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#include <iosfwd>
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#include <limits>
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namespace openmsx {
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class EmuTime
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{
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public:
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	static EmuTime dummy() { return {}; }
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	// Note: default copy constructor and assignment operator are ok.
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	[[nodiscard]] static constexpr EmuTime fromDouble(double d) {
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		return EmuTime::zero() + EmuDuration::sec(d);
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	}
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	[[nodiscard]] static constexpr EmuTime fromUint64(uint64_t t) {
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		return EmuTime(t);
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	}
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	[[nodiscard]] constexpr uint64_t toUint64() const { return time; }
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	[[nodiscard]] constexpr double toDouble() const { return EmuDuration(time).toDouble(); }
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	// comparison operators
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	[[nodiscard]] constexpr auto operator<=>(const EmuTime&) const = default;
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	// arithmetic operators
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	[[nodiscard]] constexpr friend EmuTime operator+(EmuTime l, EmuDuration r)
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		{ return EmuTime(l.toUint64() + r.toUint64()); }
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	[[nodiscard]] constexpr friend EmuTime operator-(EmuTime l, EmuDuration r)
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		{ assert(l.toUint64() >= r.toUint64());
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		  return EmuTime(l.toUint64() - r.toUint64()); }
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	[[nodiscard]] constexpr EmuTime saturateSubtract(EmuDuration r) const
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		{ return EmuTime((time >= r.time) ? time - r.time : 0); }
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	constexpr EmuTime& operator+=(EmuDuration d)
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		{ time += d.time; return *this; }
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	constexpr EmuTime& operator-=(EmuDuration d)
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		{ assert(time >= d.time);
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		  time -= d.time; return *this; }
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	[[nodiscard]] constexpr friend EmuDuration operator-(EmuTime l, EmuTime r)
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		{ assert(l.time >= r.time);
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		  return EmuDuration(l.time - r.time); }
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	[[nodiscard]] static constexpr EmuTime zero()
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	{
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		return EmuTime(uint64_t(0));
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	}
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	[[nodiscard]] static constexpr EmuTime infinity()
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	{
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		return EmuTime(std::numeric_limits<uint64_t>::max());
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	}
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	template<typename Archive>
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	void serialize(Archive& ar, unsigned /*version*/)
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	{
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		ar.serialize("time", time);
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	}
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private:
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	EmuTime() = default; // uninitialized
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	constexpr explicit EmuTime(uint64_t n) : time(n) {}
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private:
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	uint64_t time;
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	// friends
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	friend std::ostream& operator<<(std::ostream& os, EmuTime time);
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	friend class DynamicClock;
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	template<unsigned, unsigned> friend class Clock;
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};
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template<> struct SerializeAsMemcpy<EmuTime> : std::true_type {};
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} // namespace openmsx
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#endif