//
// Timestamp.h
//
// $Id: //poco/Main/Foundation/include/Foundation/Timestamp.h#5 $
//
// Definition of the Timestamp class.
//
// Copyright (c) 2004, Guenter Obiltschnig/Applied Informatics.
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 
// 3. Redistributions in any form must be accompanied by information on
//    how to obtain complete source code for this software and any
//    accompanying software that uses this software.  The source code
//    must either be included in the distribution or be available for no
//    more than the cost of distribution plus a nominal fee, and must be
//    freely redistributable under reasonable conditions.  For an
//    executable file, complete source code means the source code for all
//    modules it contains.  It does not include source code for modules or
//    files that typically accompany the major components of the operating
//    system on which the executable file runs.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//


#ifndef Foundation_Timestamp_INCLUDED
#define Foundation_Timestamp_INCLUDED


#ifndef Foundation_Foundation_INCLUDED
#include "Foundation/Foundation.h"
#endif
#ifndef STD_TIME_INCLUDED
#include <time.h>
#define STD_TIME_INCLUDED
#endif


Foundation_BEGIN


class Foundation_API Timestamp
	/// A Timestamp stores a monotonic time value
	/// with (theoretical) microseconds resolution.
	/// Timestamps can be compared with each other
	/// and simple arithmetics are supported.
	/// Timestamps are UTC (Coordinated Universal Time)
	/// based and thus independent of the timezone
	/// in effect on the system.
{
public:
	typedef Int64 TimeVal;    /// monotonic UTC time value in microsecond resolution
	typedef Int64 UtcTimeVal; /// monotonic UTC time value in 100 nanosecond resolution
	typedef Int64 TimeDiff;   /// difference between two timestamps in microseconds

	Timestamp();
		/// Creates a timestamp with the current time.
		
	Timestamp(TimeVal tv);
		/// Creates a timestamp from the given time value.
		
	Timestamp(const Timestamp& other);
		/// Copy constructor.
		
	~Timestamp();
		/// Destroys the timestamp
		
	Timestamp& operator = (const Timestamp& other);
	Timestamp& operator = (TimeVal tv);
	void update();

	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 - (TimeDiff d) const;
	TimeDiff  operator - (const Timestamp& ts) const;
	Timestamp& operator += (TimeDiff d);
	Timestamp& operator -= (TimeDiff d);
	
	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.
	
	static Timestamp fromEpochTime(time_t t);
		/// Creates a timestamp from a time_t.
		
	static Timestamp fromUtcTime(UtcTimeVal val);
		/// Creates a timestamp from a UTC time value.
		
	static TimeVal resolution();
		/// Returns the resolution in units per second.
		/// Since the timestamp has microsecond resolution,
		/// the returned value is always 1000000.

#if defined(_WIN32)
	static Timestamp fromFileTimeNP(UInt32 fileTimeLow, UInt32 fileTimeHigh);
	void toFileTimeNP(UInt32& fileTimeLow, UInt32& fileTimeHigh) const;
#endif

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 time_t Timestamp::epochTime() const
{
	return 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::TimeVal Timestamp::resolution()
{
	return 1000000;
}


Foundation_END


#endif // Foundation_Timestamp_INCLUDED