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Copy pathKTimestamp.h
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116 lines (97 loc) · 2.85 KB
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#pragma once
#include "Kcopyable.h"
#include "KTypes.h"
#include <boost/operators.hpp>
namespace kb
{
///
/// Time stamp in UTC, in microseconds resolution.
///
/// This class is immutable.
/// It's recommended to pass it by value, since it's passed in register on x64.
///
class Timestamp : public copyable,
public boost::equality_comparable<Timestamp>,
public boost::less_than_comparable<Timestamp>
{
public:
///
/// Constucts an invalid Timestamp.
///
Timestamp()
: microSecondsSinceEpoch_(0)
{
}
///
/// Constucts a Timestamp at specific time
///
/// @param microSecondsSinceEpoch
explicit Timestamp(int64_t microSecondsSinceEpochArg)
: microSecondsSinceEpoch_(microSecondsSinceEpochArg)
{
}
void swap(Timestamp &that)
{
std::swap(microSecondsSinceEpoch_, that.microSecondsSinceEpoch_);
}
// default copy/assignment/dtor are Okay
string toString() const;
string toFormattedString(bool showMicroseconds = true) const;
bool valid() const { return microSecondsSinceEpoch_ > 0; }
// for internal usage.
int64_t microSecondsSinceEpoch() const { return microSecondsSinceEpoch_; }
time_t secondsSinceEpoch() const
{
return static_cast<time_t>(microSecondsSinceEpoch_ / kMicroSecondsPerSecond);
}
///
/// Get time of now.
///
static Timestamp now();
static Timestamp invalid()
{
return Timestamp();
}
static Timestamp fromUnixTime(time_t t)
{
return fromUnixTime(t, 0);
}
static Timestamp fromUnixTime(time_t t, int microseconds)
{
return Timestamp(static_cast<int64_t>(t) * kMicroSecondsPerSecond + microseconds);
}
static const int kMicroSecondsPerSecond = 1000 * 1000;
private:
int64_t microSecondsSinceEpoch_;
};
inline bool operator<(Timestamp lhs, Timestamp rhs)
{
return lhs.microSecondsSinceEpoch() < rhs.microSecondsSinceEpoch();
}
inline bool operator==(Timestamp lhs, Timestamp rhs)
{
return lhs.microSecondsSinceEpoch() == rhs.microSecondsSinceEpoch();
}
///
/// Gets time difference of two timestamps, result in seconds.
///
/// @param high, low
/// @return (high-low) in seconds
/// @c double has 52-bit precision, enough for one-microsecond
/// resolution for next 100 years.
inline double timeDifference(Timestamp high, Timestamp low)
{
int64_t diff = high.microSecondsSinceEpoch() - low.microSecondsSinceEpoch();
return static_cast<double>(diff) / Timestamp::kMicroSecondsPerSecond;
}
///
/// Add @c seconds to given timestamp.
///
/// @return timestamp+seconds as Timestamp
///
inline Timestamp addTime(Timestamp timestamp, double seconds)
{
int64_t delta = static_cast<int64_t>(seconds * Timestamp::kMicroSecondsPerSecond);
return Timestamp(timestamp.microSecondsSinceEpoch() + delta);
}
} // namespace kb