libchill/remaintime.c

   1 /* Implement timing-related runtime actions for CHILL.
   2    Copyright (C) 1992,1993 Free Software Foundation, Inc.
   3    Author: Wilfried Moser
   4
   5    This file is part of GNU CC.
   6
   7    GNU CC is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GNU CC is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GNU CC; see the file COPYING.  If not, write to
  19    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* As a special exception, if you link this library with other files,
  22    some of which are compiled with GCC, to produce an executable,
  23    this library does not by itself cause the resulting executable
  24    to be covered by the GNU General Public License.
  25    This exception does not however invalidate any other reasons why
  26    the executable file might be covered by the GNU General Public License.  */
  27
  28 #include "rts.h"
  29
  30 /*
  31  * function __remaintime
  32  *
  33  * parameters:
  34  *      since   pointer to the  initial RtsTime
  35  *      dur     the duration value
  36  *      t       pointer to the remaining RtsTime
  37  *
  38  * returns:
  39  *      int     0 .. there is a remaining time
  40  *              1 .. there is no remaining time
  41  *
  42  * exceptions:
  43  *      none
  44  *
  45  * abstract:
  46  *      This function writes to t the remaining duration value in RtsTime format
  47  *      from a given start (since) and the current RtsTime.
  48  *
  49  */
  50
  51 extern void __convert_duration_rtstime (unsigned long dur, RtsTime *t);
  52
  53 int
  54   __remaintime (since, dur, t)
  55 RtsTime       *since;
  56 unsigned long  dur;
  57 RtsTime       *t;
  58 {
  59   RtsTime now, dur_in_rtstime, tmp, diff;
  60
  61   __rtstime (&now);
  62   __convert_duration_rtstime (dur, &dur_in_rtstime);
  63
  64   tmp.secs = since->secs;
  65   tmp.nanosecs = since->nanosecs;
  66
  67   /* calculate the difference of absolute times */
  68   if (tmp.nanosecs > now.nanosecs)
  69     {
  70       tmp.secs--;
  71       tmp.nanosecs += 1000000000;
  72     }
  73   diff.secs = now.secs - tmp.secs;
  74   diff.nanosecs = now.nanosecs - tmp.nanosecs;
  75
  76   /* substract diff from duration */
  77   if (diff.nanosecs > dur_in_rtstime.nanosecs)
  78     {
  79       dur_in_rtstime.secs--;
  80       dur_in_rtstime.nanosecs += 1000000000;
  81     }
  82
  83   t->secs = dur_in_rtstime.secs - diff.secs;
  84   t->nanosecs = dur_in_rtstime.nanosecs - diff.nanosecs;
  85
  86   if (t->secs > dur_in_rtstime.secs)
  87     return 1;
  88   else
  89     return 0;
  90 }