/*---------------------------------------------------------------------------*
 *                                   IT++			             *
 *---------------------------------------------------------------------------*
 * Copyright (c) 1995-2003 by Tony Ottosson, Thomas Eriksson, Pål Frenger,   *
 * Tobias Ringström, and Jonas Samuelsson.                                   *
 *                                                                           *
 * Permission to use, copy, modify, and distribute this software and its     *
 * documentation under the terms of the GNU General Public License is hereby *
 * granted. No representations are made about the suitability of this        *
 * software for any purpose. It is provided "as is" without expressed or     *
 * implied warranty. See the GNU General Public License for more details.    *
 *---------------------------------------------------------------------------*/

/*! 
  \file 
  \brief Definitions of Timing classes
  \author Thomas Eriksson, Tony Ottosson, and Tobias Ringström

  1.10

  2003/11/28 10:16:05
*/

#ifndef __timing_h
#define __timing_h

namespace itpp {

/*!
  \defgroup timers Timers
*/

/*! 
  \brief A virtual base class for timers.
  \ingroup timers
*/
class Timer {
public:
    //! Create a new timer.  Sets the time to zero.
    Timer();
    //! Virtual destructor
    virtual ~Timer() { }
    //! Start the timer.  This does not set the time to zero.
    void start(void);
    //! Stop the timer.  Returns the elapsed time in seconds.
    double stop(void);
    //! Sets the time to time t, which is zero by default. Stops the timer if it is running.
    void reset(double t=0.0);
    //! Resets the timer and starts it.
    void tic(void);
    //! Returns the elapsed time since last tic()
    double toc(void);
    //! Prints the elapsed time since last tic()
    void toc_print(void);
    //! Returns the elapsed time.
    double get_time() const;
    
protected:
    //! Vitrual function that returns teh current time
    virtual double get_current_time() const = 0;
    //! The start time of the timer
    double start_time;
    //! The stop time of the timer
    double stop_time;
    //! The ellapsed time from start to stop
    double elapsed_time;
    //! A bool that indicates if the timer is running or not
    bool running;
};

/*! 
  \brief A CPU time timer class
  \ingroup timers

  Measures the time spent by the CPU on the current process.  If two processes
  are running concurrently, one real seconds equal 5 CPU seconds per process.
  The resolution is not very good (in the order of 0.01 seconds).
  
  Usage: Define a time object:
  \code
  CPU_Timer timer;
  \endcode
  
  Actions:
  Reset: \code timer.reset(); \endcode
  Start: \code timer.start(); \endcode
  Stop: \code timer.stop(); \endcode
  Get time: \code elapsedtime = timer.get_time(); \endcode

  It is possible to get elapsed time without stopping the timer.
  Observe that it is also possible to use the macros "time.tic();"
  to reset and start clock and "time.toc();" stop and print the elapsed time.
  \warning May give an negative answer if the measured time is too long.
*/
class CPU_Timer : public Timer {
public:
    //! Create a new timer. Sets the time to zero.
    CPU_Timer() { }

protected:
    //!
    double get_current_time() const;
};

/*! 
  \brief A real time timer class
  \ingroup timers

  Measures real time.
  
  Usage: Define a time object:
  \code
  Real_Timer timer;
  \endcode
  
  Actions:
  Reset: \code timer.reset(); \endcode
  Start: \code timer.start(); \endcode
  Stop: \code timer.stop(); \endcode
  Get time: \code elapsedtime = timer.get_time(); \endcode

  It is possible to get elapsed time without stopping the timer.
  Observe that it is also possible to use the macros "time.tic();"
  to reset and start clock and "time.toc();" stop and print the elapsed time.
  
  \warning May give an negative answer if the measured time is too long.
*/
class Real_Timer : public Timer {
public:
    //! Create a new timer. Sets the time to zero.
    Real_Timer() { }
    
protected:
    //!
    double get_current_time() const;
};

/*! 
  \brief Reset and start timer
  \ingroup timers
*/
void tic();

/*! 
  \brief Returns the elapsed time since last tic()
  \ingroup timers
*/
double toc();

/*! 
  \brief Prints the elapsed time since last tic()
  \ingroup timers
*/
void toc_print();

/*! 
  \brief pause
  \ingroup timers

  \code pause(n); \endcode  Pauses for n seconds before continuing
  \code pause(); \endcode  Pauses until a key is pressed

*/
void pause(double t=-1);

} //namespace itpp

#endif // __timing_h