// hrtimer.h - originally written and placed in the public domain by Wei Dai

/// \file hrtimer.h

/// \brief Classes for timers

#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

  /// \brief TimerWord is a 64-bit word

  typedef word64 TimerWord;

#else

  /// \brief TimerWord is a clock_t

  typedef clock_t TimerWord;

#endif

/// \brief Base class for timers

/// \sa ThreadUserTimer, Timer

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE TimerBase

{

public:

  /// \brief Unit of measure

  /// \details Unit selects the unit of measure as returned by functions

  ///  ElapsedTimeAsDouble() and ElapsedTime().

  /// \sa ElapsedTimeAsDouble, ElapsedTime

  enum Unit {

    /// \brief Timer unit is seconds

    /// \details All timers support seconds

    SECONDS = 0,

    /// \brief Timer unit is milliseconds

    /// \details All timers support milliseconds

    MILLISECONDS,

    /// \brief Timer unit is microseconds

    /// \details The timer requires hardware support microseconds

    MICROSECONDS,

    /// \brief Timer unit is nanoseconds

    /// \details The timer requires hardware support nanoseconds

    NANOSECONDS

  };

  /// \brief Construct a TimerBase

  /// \param unit the unit of measure

  /// \param stuckAtZero flag

  TimerBase(Unit unit, bool stuckAtZero)

    : m_timerUnit(unit), m_stuckAtZero(stuckAtZero), m_started(false)

    , m_start(0), m_last(0) {}

  /// \brief Retrieve the current timer value

  /// \return the current timer value

  virtual TimerWord GetCurrentTimerValue() =0;

  /// \brief Retrieve ticks per second

  /// \return ticks per second

  /// \details TicksPerSecond() is not the timer resolution. It is a

  ///  conversion factor into seconds.

  virtual TimerWord TicksPerSecond() =0;

  /// \brief Start the timer

  void StartTimer();

  /// \brief Retrieve the elapsed time

  /// \return the elapsed time as a double

  /// \details The return value of ElapsedTimeAsDouble() depends upon

  ///  the Unit selected during construction of the timer. For example,

  ///  if <tt>Unit = SECONDS</tt> and ElapsedTimeAsDouble() returns 3,

  ///  then the timer has run for 3 seconds. If

  ///  <tt>Unit = MILLISECONDS</tt> and ElapsedTimeAsDouble() returns

  ///  3000, then the timer has run for 3 seconds.

  /// \sa Unit, ElapsedTime

  double ElapsedTimeAsDouble();

  /// \brief Retrieve the elapsed time

  /// \return the elapsed time as an unsigned long

  /// \details The return value of ElapsedTime() depends upon the

  ///  Unit selected during construction of the timer. For example, if

  ///  <tt>Unit = SECONDS</tt> and ElapsedTime() returns 3, then

  ///  the timer has run for 3 seconds. If <tt>Unit = MILLISECONDS</tt>

  ///  and ElapsedTime() returns 3000, then the timer has run for 3

  ///  seconds.

  /// \sa Unit, 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

/// \details ThreadUserTimer requires support of the OS. On Unix-based it

///  reports process time. On Windows NT or later desktops and servers it

///  reports thread times with performance counter precision.. On Windows

///  Phone and Windows Store it reports wall clock time with performance

///  counter precision. On all others it reports wall clock time.

/// \note ThreadUserTimer only works correctly on Windows NT or later

///  desktops and servers.

/// \sa Timer

class ThreadUserTimer : public TimerBase

{

public:

  /// \brief Construct a ThreadUserTimer

  /// \param unit the unit of measure

  /// \param stuckAtZero flag

  ThreadUserTimer(Unit unit = TimerBase::SECONDS, bool stuckAtZero = false) : TimerBase(unit, stuckAtZero) {}

  TimerWord GetCurrentTimerValue();

  TimerWord TicksPerSecond();

};

/// \brief High resolution timer

/// \sa ThreadUserTimer

class CRYPTOPP_DLL Timer : public TimerBase

{

public:

  /// \brief Construct a Timer

  /// \param unit the unit of measure

  /// \param stuckAtZero flag

  Timer(Unit unit = TimerBase::SECONDS, bool stuckAtZero = false) : TimerBase(unit, stuckAtZero) {}

  TimerWord GetCurrentTimerValue();

  TimerWord TicksPerSecond();

};

NAMESPACE_END

#endif