/*
 * Compilation Copyright (c) 1995-2019 by Wei Dai.  All rights reserved.
 *	This copyright applies only to this software distribution package
 *	as a compilation, and does not imply a copyright on any particular
 *	file in the package.
 * 
 *	Boost Software License - Version 1.0 - August 17th, 2003
 *
 *	Permission is hereby granted, free of charge, to any person or organization
 *	obtaining a copy of the software and accompanying documentation covered by
 *	this license (the "Software") to use, reproduce, display, distribute,
 *	execute, and transmit the Software, and to prepare derivative works of the
 *	Software, and to permit third-parties to whom the Software is furnished to
 *	do so, all subject to the following:
 * 
 *	The copyright notices in the Software and this entire statement, including
 *	the above license grant, this restriction and the following disclaimer,
 *	must be included in all copies of the Software, in whole or in part, and
 *	all derivative works of the Software, unless such copies or derivative
 *	works are solely in the form of machine-executable object code generated by
 *	a source language processor.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
 *	SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
 *	FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
 *	ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 *	DEALINGS IN THE SOFTWARE.
 */

#ifndef CRYPTOPP_HRTIMER_H
#define CRYPTOPP_HRTIMER_H

#include "config.h"

#if !defined(HIGHRES_TIMER_AVAILABLE) || (defined(CRYPTOPP_WIN32_AVAILABLE) && !defined(THREAD_TIMER_AVAILABLE))
#include <time.h>
#endif

NAMESPACE_BEGIN(CryptoPP)

#ifdef HIGHRES_TIMER_AVAILABLE
	typedef word64 TimerWord;
#else
	typedef clock_t TimerWord;
#endif

/// \brief Base class for timers
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE TimerBase
{
public:
	enum Unit {SECONDS = 0, MILLISECONDS, MICROSECONDS, NANOSECONDS};
	TimerBase(Unit unit, bool stuckAtZero)
		: m_timerUnit(unit), m_stuckAtZero(stuckAtZero), m_started(false)
		, m_start(0), m_last(0) {}

	virtual TimerWord GetCurrentTimerValue() =0;	// GetCurrentTime is a macro in MSVC 6.0
	virtual TimerWord TicksPerSecond() =0;	// this is not the resolution, just a conversion factor into seconds

	void StartTimer();
	double ElapsedTimeAsDouble();
	unsigned long ElapsedTime();

private:
	double ConvertTo(TimerWord t, Unit unit);

	Unit m_timerUnit;	// HPUX workaround: m_unit is a system macro on HPUX
	bool m_stuckAtZero, m_started;
	TimerWord m_start, m_last;
};

/// \brief Measure CPU time spent executing instructions of this thread (if supported by OS)
/// \note ThreadUserTimer only works correctly on Windows NT or later desktops and servers.
/// On Unix-based it reports process time. On Windows Phone and Windows Store it reports wall
/// clock time with performance counter precision. On all others it reports wall clock time.
class ThreadUserTimer : public TimerBase
{
public:
	ThreadUserTimer(Unit unit = TimerBase::SECONDS, bool stuckAtZero = false) : TimerBase(unit, stuckAtZero) {}
	TimerWord GetCurrentTimerValue();
	TimerWord TicksPerSecond();
};

/// high resolution timer
class CRYPTOPP_DLL Timer : public TimerBase
{
public:
	Timer(Unit unit = TimerBase::SECONDS, bool stuckAtZero = false)	: TimerBase(unit, stuckAtZero) {}
	TimerWord GetCurrentTimerValue();
	TimerWord TicksPerSecond();
};

NAMESPACE_END

#endif
