ClickHouse/base/poco/Foundation/include/Poco/Timestamp.h
2023-02-14 22:13:11 +00:00

275 lines
6.1 KiB
C++

//
// Timestamp.h
//
// Library: Foundation
// Package: DateTime
// Module: Timestamp
//
// Definition of the Timestamp class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_Timestamp_INCLUDED
#define Foundation_Timestamp_INCLUDED
#include <ctime>
#include "Poco/Foundation.h"
namespace Poco
{
class Timespan;
class Foundation_API Timestamp
/// A Timestamp stores a monotonic* time value
/// with (theoretical) microseconds resolution.
/// Timestamps can be compared with each other
/// and simple arithmetic are supported.
///
/// [*] Note that Timestamp values are only monotonic as
/// long as the systems's clock is monotonic as well
/// (and not, e.g. set back due to time synchronization
/// or other reasons).
///
/// Timestamps are UTC (Coordinated Universal Time)
/// based and thus independent of the timezone
/// in effect on the system.
///
/// The internal reference time is the Unix epoch,
/// midnight, January 1, 1970.
{
public:
typedef Int64 TimeVal;
/// Monotonic UTC time value in microsecond resolution,
/// with base time midnight, January 1, 1970.
typedef Int64 UtcTimeVal;
/// Monotonic UTC time value in 100 nanosecond resolution,
/// with base time midnight, October 15, 1582.
typedef Int64 TimeDiff;
/// Difference between two TimeVal values in microseconds.
static const TimeVal TIMEVAL_MIN; /// Minimum timestamp value.
static const TimeVal TIMEVAL_MAX; /// Maximum timestamp value.
Timestamp();
/// Creates a timestamp with the current time.
Timestamp(TimeVal tv);
/// Creates a timestamp from the given time value
/// (microseconds since midnight, January 1, 1970).
Timestamp(const Timestamp & other);
/// Copy constructor.
~Timestamp();
/// Destroys the timestamp
Timestamp & operator=(const Timestamp & other);
Timestamp & operator=(TimeVal tv);
void swap(Timestamp & timestamp);
/// Swaps the Timestamp with another one.
void update();
/// Updates the Timestamp with the current time.
bool operator==(const Timestamp & ts) const;
bool operator!=(const Timestamp & ts) const;
bool operator>(const Timestamp & ts) const;
bool operator>=(const Timestamp & ts) const;
bool operator<(const Timestamp & ts) const;
bool operator<=(const Timestamp & ts) const;
Timestamp operator+(TimeDiff d) const;
Timestamp operator+(const Timespan & span) const;
Timestamp operator-(TimeDiff d) const;
Timestamp operator-(const Timespan & span) const;
TimeDiff operator-(const Timestamp & ts) const;
Timestamp & operator+=(TimeDiff d);
Timestamp & operator+=(const Timespan & span);
Timestamp & operator-=(TimeDiff d);
Timestamp & operator-=(const Timespan & span);
std::time_t epochTime() const;
/// Returns the timestamp expressed in time_t.
/// time_t base time is midnight, January 1, 1970.
/// Resolution is one second.
UtcTimeVal utcTime() const;
/// Returns the timestamp expressed in UTC-based
/// time. UTC base time is midnight, October 15, 1582.
/// Resolution is 100 nanoseconds.
TimeVal epochMicroseconds() const;
/// Returns the timestamp expressed in microseconds
/// since the Unix epoch, midnight, January 1, 1970.
TimeDiff elapsed() const;
/// Returns the time elapsed since the time denoted by
/// the timestamp. Equivalent to Timestamp() - *this.
bool isElapsed(TimeDiff interval) const;
/// Returns true iff the given interval has passed
/// since the time denoted by the timestamp.
TimeVal raw() const;
/// Returns the raw time value.
///
/// Same as epochMicroseconds().
static Timestamp fromEpochTime(std::time_t t);
/// Creates a timestamp from a std::time_t.
static Timestamp fromUtcTime(UtcTimeVal val);
/// Creates a timestamp from a UTC time value
/// (100 nanosecond intervals since midnight,
/// October 15, 1582).
static TimeDiff resolution();
/// Returns the resolution in units per second.
/// Since the timestamp has microsecond resolution,
/// the returned value is always 1000000.
private:
TimeVal _ts;
};
//
// inlines
//
inline bool Timestamp::operator==(const Timestamp & ts) const
{
return _ts == ts._ts;
}
inline bool Timestamp::operator!=(const Timestamp & ts) const
{
return _ts != ts._ts;
}
inline bool Timestamp::operator>(const Timestamp & ts) const
{
return _ts > ts._ts;
}
inline bool Timestamp::operator>=(const Timestamp & ts) const
{
return _ts >= ts._ts;
}
inline bool Timestamp::operator<(const Timestamp & ts) const
{
return _ts < ts._ts;
}
inline bool Timestamp::operator<=(const Timestamp & ts) const
{
return _ts <= ts._ts;
}
inline Timestamp Timestamp::operator+(Timestamp::TimeDiff d) const
{
return Timestamp(_ts + d);
}
inline Timestamp Timestamp::operator-(Timestamp::TimeDiff d) const
{
return Timestamp(_ts - d);
}
inline Timestamp::TimeDiff Timestamp::operator-(const Timestamp & ts) const
{
return _ts - ts._ts;
}
inline Timestamp & Timestamp::operator+=(Timestamp::TimeDiff d)
{
_ts += d;
return *this;
}
inline Timestamp & Timestamp::operator-=(Timestamp::TimeDiff d)
{
_ts -= d;
return *this;
}
inline std::time_t Timestamp::epochTime() const
{
return std::time_t(_ts / resolution());
}
inline Timestamp::UtcTimeVal Timestamp::utcTime() const
{
return _ts * 10 + (TimeDiff(0x01b21dd2) << 32) + 0x13814000;
}
inline Timestamp::TimeVal Timestamp::epochMicroseconds() const
{
return _ts;
}
inline Timestamp::TimeDiff Timestamp::elapsed() const
{
Timestamp now;
return now - *this;
}
inline bool Timestamp::isElapsed(Timestamp::TimeDiff interval) const
{
Timestamp now;
Timestamp::TimeDiff diff = now - *this;
return diff >= interval;
}
inline Timestamp::TimeDiff Timestamp::resolution()
{
return 1000000;
}
inline void swap(Timestamp & s1, Timestamp & s2)
{
s1.swap(s2);
}
inline Timestamp::TimeVal Timestamp::raw() const
{
return _ts;
}
} // namespace Poco
#endif // Foundation_Timestamp_INCLUDED