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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef FLUTTER_FML_TIME_TIME_POINT_H_
#define FLUTTER_FML_TIME_TIME_POINT_H_
#include <cstdint>
#include <functional>
#include <iosfwd>
#include "flutter/fml/time/time_delta.h"
namespace fml {
// A TimePoint represents a point in time represented as an integer number of
// nanoseconds elapsed since an arbitrary point in the past.
//
// WARNING: This class should not be serialized across reboots, or across
// devices: the reference point is only stable for a given device between
// reboots.
class TimePoint {
public:
using ClockSource = TimePoint (*)();
// Default TimePoint with internal value 0 (epoch).
constexpr TimePoint() = default;
static void SetClockSource(ClockSource source);
static TimePoint Now();
static TimePoint CurrentWallTime();
static constexpr TimePoint Min() {
return TimePoint(std::numeric_limits<int64_t>::min());
}
static constexpr TimePoint Max() {
return TimePoint(std::numeric_limits<int64_t>::max());
}
static constexpr TimePoint FromEpochDelta(TimeDelta ticks) {
return TimePoint(ticks.ToNanoseconds());
}
// Expects ticks in nanos.
static constexpr TimePoint FromTicks(int64_t ticks) {
return TimePoint(ticks);
}
TimeDelta ToEpochDelta() const { return TimeDelta::FromNanoseconds(ticks_); }
// Compute the difference between two time points.
TimeDelta operator-(TimePoint other) const {
return TimeDelta::FromNanoseconds(ticks_ - other.ticks_);
}
TimePoint operator+(TimeDelta duration) const {
return TimePoint(ticks_ + duration.ToNanoseconds());
}
TimePoint operator-(TimeDelta duration) const {
return TimePoint(ticks_ - duration.ToNanoseconds());
}
bool operator==(TimePoint other) const { return ticks_ == other.ticks_; }
bool operator!=(TimePoint other) const { return ticks_ != other.ticks_; }
bool operator<(TimePoint other) const { return ticks_ < other.ticks_; }
bool operator<=(TimePoint other) const { return ticks_ <= other.ticks_; }
bool operator>(TimePoint other) const { return ticks_ > other.ticks_; }
bool operator>=(TimePoint other) const { return ticks_ >= other.ticks_; }
private:
explicit constexpr TimePoint(int64_t ticks) : ticks_(ticks) {}
int64_t ticks_ = 0;
};
} // namespace fml
#endif // FLUTTER_FML_TIME_TIME_POINT_H_