timer.hh

Go to the documentation of this file.

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_TIMER_HH
#define DUNE_TIMER_HH

#ifndef TIMER_USE_STD_CLOCK
// headers for getrusage(2)
#include <sys/resource.h>
#endif

#include <ctime>

// headers for stderror(3)
#include <cstring>

// access to errno in C++
#include <cerrno>

#include "exceptions.hh"

namespace Dune {

  class TimerError : public SystemError {} ;


  class Timer
  {
  public:

    Timer (bool startImmediately=true) throw(TimerError)
    {
      isRunning_ = startImmediately;
      reset();
    }

    void reset() throw (TimerError)
    {
      sumElapsed_ = 0.0;
      storedLastElapsed_ = 0.0;
      rawReset();
    }


    void start() throw (TimerError)
    {
      if (not (isRunning_))
      {
        rawReset();
        isRunning_ = true;
      }
    }


    double elapsed () const throw (TimerError)
    {
      // if timer is running add the time elapsed since last start to sum
      if (isRunning_)
        return sumElapsed_ + lastElapsed();

      return sumElapsed_;
    }


    double lastElapsed () const throw (TimerError)
    {
      // if timer is running return the current value
      if (isRunning_)
        return rawElapsed();

      // if timer is not running return stored value from last run
      return storedLastElapsed_;
    }


    double stop() throw (TimerError)
    {
      if (isRunning_)
      {
        // update storedLastElapsed_ and  sumElapsed_ and stop timer
        storedLastElapsed_ = lastElapsed();
        sumElapsed_ += storedLastElapsed_;
        isRunning_ = false;
      }
      return elapsed();
    }


  private:

    bool isRunning_;
    double sumElapsed_;
    double storedLastElapsed_;


#ifdef TIMER_USE_STD_CLOCK
    void rawReset() throw (TimerError)
    {
      cstart = std::clock();
    }

    double rawElapsed () const throw (TimerError)
    {
      return (std::clock()-cstart) / static_cast<double>(CLOCKS_PER_SEC);
    }

    std::clock_t cstart;
#else
    void rawReset() throw (TimerError)
    {
      rusage ru;
      if (getrusage(RUSAGE_SELF, &ru))
        DUNE_THROW(TimerError, strerror(errno));
      cstart = ru.ru_utime;
    }

    double rawElapsed () const throw (TimerError)
    {
      rusage ru;
      if (getrusage(RUSAGE_SELF, &ru))
        DUNE_THROW(TimerError, strerror(errno));
      return 1.0 * (ru.ru_utime.tv_sec - cstart.tv_sec) + (ru.ru_utime.tv_usec - cstart.tv_usec) / (1000.0 * 1000.0);
    }

    struct timeval cstart;
#endif
  }; // end class Timer

} // end namespace

#endif