/*
 * Copyright (c) 1996 Gunther Schadow.  All rights reserved.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#pragma implementation

#include <Timer.h>
#include <Signal.h>

/**********************************************************************
 * Timer
 **********************************************************************/

Signal Timer::_sigalrm(SIGALRM, alrmsuperhandler,
		       0, Signal::f_restart | Signal::f_disable);
Timer  *Timer::_active_timer = NULL;

int Timer::alrmsuperhandler(Signal &)
{
  if(_active_timer == NULL)
    return 0; // not my signal;
  
  Timer &that = *_active_timer;

  that._alrm_cnt++;
  if(that._handler != NULL)
    (that._handler)(that);
  
  return 1; // we assume that the signal was for us
}

Timer::Timer(u_int vsec, u_int vusec, u_int isec, u_int iusec, alrmhdl_t hdl)
{
  bool b = _sigalrm.block();
  _handler    = hdl;
  _alrm_cnt   = 0;
  _orig_timer = NULL;
  _val.it_value.tv_sec     = vsec;
  _val.it_value.tv_usec    = vusec;
  _val.it_interval.tv_sec  = isec;
  _val.it_interval.tv_usec = iusec;
  _init_val = _val.it_value;
  getitimer(ITIMER_REAL, &_orig_val);  
  _orig_timer   = _active_timer;
  _active_timer = this;
  setitimer(ITIMER_REAL, &_val, &_orig_val);
  _sigalrm.block(b);
}

Timer::~Timer()
{
  bool b = _sigalrm.block();
  if(_active_timer == this)
    _active_timer = _orig_timer;

  // Calculate the new timer value
  itimerval now;			// the current value
  getitimer(ITIMER_REAL, &now);
  Timeval t(_val.it_interval);	        // the current interval
  t *= _alrm_cnt;			// times the number of timeouts
  t += _init_val;			// plus the value first loaded
  *(Timeval*)&_val.it_interval -= *(Timeval*)&now.it_value;	
  t += _val.it_interval;		// plus time since last timeout
  // t is the time elapsed since this timer was installed

  *(Timeval*)&_orig_val.it_value -= t;	// update the original value

  setitimer(ITIMER_REAL, &_orig_val, NULL);
  _sigalrm.block(b);
}

void Timer::get(u_int *vsec, u_int *vusec, u_int *isec, u_int *iusec) const
{
  itimerval val;
  getitimer(ITIMER_REAL, &val);  
  if(vsec != NULL)
    *vsec  = val.it_value.tv_sec;
  if(vusec != NULL)
    *vusec = val.it_value.tv_usec;
  if(isec != NULL)
    *isec  = val.it_interval.tv_sec;
  if(iusec != NULL)
    *iusec = val.it_interval.tv_usec;
}

/**********************************************************************
 * Timeval
 **********************************************************************/

const Timeval    Timeval::null(0, 0);

const Timeval &Timeval::operator -= (const Timeval &x)
{
  long us = tv_usec - x.tv_usec;
  long  s = tv_sec  - x.tv_sec;
  if(us < 0)
    {
      long compl = us / 1000001 + 1;
      tv_sec     = s  - compl;
      tv_usec    = us +1000000 * compl;      
    }
  else
    {
      tv_sec  = s + us / 1000000;
      tv_usec = us % 1000000;
    }
  if(tv_sec < 0)
    {
      tv_sec = 0;
      tv_usec = 0;
    }
  return *this;
}

void Timer::sleep(u_int vsec, u_int vusec)
{
  Timer t1(vsec, vusec);
  while(!t1.expired()) pause();
}

Timeval::Timeval(u_int sec, u_int usec)
{ 
  tv_sec  = sec + usec / 1000000;
  tv_usec = usec % 1000000;
}
 
const Timeval &Timeval::operator += (const Timeval &x)
{
  tv_usec += x.tv_usec;
  tv_sec  += x.tv_sec + tv_usec / 1000000;
  tv_usec = tv_usec % 1000000;
  return *this;
}

const Timeval &Timeval::operator *= (u_int x)
{
  tv_usec *= x;
  tv_sec  *= x; 
  tv_sec  = tv_sec  + tv_usec / 1000000;
  tv_usec = tv_usec % 1000000;
  return *this;
}