/* Implement timing-related runtime actions for CHILL.
   Copyright (C) 1992,1993 Free Software Foundation, Inc.
   Author: Wilfried Moser
   
   This file is part of GNU CC.
   
   GNU CC 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, or (at your option)
   any later version.
   
   GNU CC 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 GNU CC; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "rts.h"

/*
 * function __remaintime
 *
 * parameters:
 *      since   pointer to the  initial RtsTime
 *      dur     the duration value
 *      t       pointer to the remaining RtsTime
 *
 * returns:
 *      int     0 .. there is a remaining time
 *              1 .. there is no remaining time
 *
 * exceptions:
 *      none
 *
 * abstract:
 *      This function writes to t the remaining duration value in RtsTime format
 *      from a given start (since) and the current RtsTime.
 *
 */

extern void __convert_duration_rtstime (unsigned long dur, RtsTime *t);

int
  __remaintime (since, dur, t)
RtsTime       *since;
unsigned long  dur;
RtsTime       *t;
{
  RtsTime now, dur_in_rtstime, tmp, diff;
  
  __rtstime (&now);
  __convert_duration_rtstime (dur, &dur_in_rtstime);
  
  tmp.secs = since->secs;
  tmp.nanosecs = since->nanosecs;
  
  /* calculate the difference of absolute times */
  if (tmp.nanosecs > now.nanosecs)
    {
      tmp.secs--;
      tmp.nanosecs += 1000000000;
    }
  diff.secs = now.secs - tmp.secs;
  diff.nanosecs = now.nanosecs - tmp.nanosecs;
  
  /* substract diff from duration */
  if (diff.nanosecs > dur_in_rtstime.nanosecs)
    {
      dur_in_rtstime.secs--;
      dur_in_rtstime.nanosecs += 1000000000;
    }
  
  t->secs = dur_in_rtstime.secs - diff.secs;
  t->nanosecs = dur_in_rtstime.nanosecs - diff.nanosecs;
  
  if (t->secs > dur_in_rtstime.secs)
    return 1;
  else
    return 0;
}