#ifndef __Timer_hh__
#define __Timer_hh__

// Copyright (C) 2002 David R. Martin <dmartin@eecs.berkeley.edu>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA, or see http://www.gnu.org/copyleft/gpl.html.

#include <sys/times.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include <assert.h>

class Timer
{
public:

    inline Timer ();
    inline ~Timer ();
    
    inline void start ();
    inline void stop ();
    inline void reset ();

    // All times are in seconds.
    inline double cpu ();	
    inline double user ();
    inline double system ();
    inline double elapsed ();

    // Convert time in seconds into a nice human-friendly format: h:mm:ss.ss
    // Precision is the number of digits after the decimal.
    // Return a pointer to a static buffer.
    static const char* formatTime (double sec, int precision = 2);
    
private:

    void _compute ();
  
    enum State { stopped, running };

    State _state;
  
    struct timeval _elapsed_start;
    struct timeval _elapsed_stop;
    double _elapsed;

    struct tms _cpu_start;
    struct tms _cpu_stop;
    double _user;
    double _system;
};

Timer::Timer ()
{
    reset ();
}

Timer::~Timer ()
{
}

void
Timer::reset ()
{
    _state = stopped;
    _elapsed = _user = _system = 0;
}

void
Timer::start ()
{
    assert (_state == stopped);
    _state = running;
    gettimeofday (&_elapsed_start, NULL);
    times (&_cpu_start);
}

void
Timer::stop ()
{
    assert (_state == running);
    gettimeofday (&_elapsed_stop, NULL);
    times (&_cpu_stop);
    _compute ();
   _state = stopped;
}

double
Timer::cpu ()
{
    assert (_state == stopped);
    return _user + _system;
}

double
Timer::user ()
{
    assert (_state == stopped);
    return _user;
}

double
Timer::system ()
{
    assert (_state == stopped);
    return _system;
}

double
Timer::elapsed ()
{
    assert (_state == stopped);
    return _elapsed;
}

#endif // __Timer_hh__