hrtimer.h

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// 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