larn/nap.c

   1 #ifndef lint
   2 static char rcsid[] = "$Id: nap.c,v 1.2 1993/08/02 17:20:15 mycroft Exp $";
   3 #endif /* not lint */
   4
   5 /* nap.c                 Larn is copyrighted 1986 by Noah Morgan. */
   6 #include <signal.h>
   7 #include <sys/types.h>
   8 #ifdef SYSV
   9 #include <sys/times.h>
  10 #else
  11 #ifdef BSD
  12 #include <sys/timeb.h>
  13 #endif BSD
  14 #endif SYSV
  15
  16 /*
  17  *      routine to take a nap for n milliseconds
  18  */
  19 nap(x)
  20         register int x;
  21         {
  22         if (x<=0) return; /* eliminate chance for infinite loop */
  23         lflush();
  24         if (x > 999) sleep(x/1000); else napms(x);
  25         }
  26
  27 #ifdef NONAP
  28 napms(x)        /* do nothing */
  29         int x;
  30         {
  31         }
  32 #else NONAP
  33 #ifdef SYSV
  34 /*      napms - sleep for time milliseconds - uses times() */
  35 /* this assumes that times returns a relative time in 60ths of a second */
  36 /* this will do horrible things if your times() returns seconds! */
  37 napms(time)
  38         int time;
  39         {
  40         long matchclock, times();
  41         struct tms stats;
  42
  43         if (time<=0) time=1; /* eliminate chance for infinite loop */
  44         if ((matchclock = times(&stats)) == -1 || matchclock == 0)
  45                 return; /* error, or BSD style times() */
  46         matchclock += (time / 17);              /*17 ms/tic is 1000 ms/sec / 60 tics/sec */
  47
  48         while(matchclock < times(&stats))
  49                 ;
  50         }
  51
  52 #else not SYSV
  53 #ifdef BSD
  54 #ifdef SIGVTALRM
  55 /* This must be BSD 4.2!  */
  56 #include <sys/time.h>
  57 #define bit(_a) (1<<((_a)-1))
  58
  59 static  nullf()
  60     {
  61     }
  62
  63 /*      napms - sleep for time milliseconds - uses setitimer() */
  64 napms(time)
  65         int time;
  66     {
  67     struct itimerval    timeout;
  68     int     (*oldhandler) ();
  69     int     oldsig;
  70
  71         if (time <= 0) return;
  72
  73     timerclear(&timeout.it_interval);
  74     timeout.it_value.tv_sec = time / 1000;
  75     timeout.it_value.tv_usec = (time % 1000) * 1000;
  76
  77     oldsig = sigblock(bit(SIGALRM));
  78     setitimer(ITIMER_REAL, &timeout, (struct itimerval *)0);
  79     oldhandler = signal(SIGALRM, nullf);
  80     sigpause(oldsig);
  81     signal(SIGALRM, oldhandler);
  82     sigsetmask(oldsig);
  83     }
  84
  85 #else
  86 /*      napms - sleep for time milliseconds - uses ftime() */
  87
  88 static napms(time)
  89         int time;
  90         {
  91         /* assumed to be BSD UNIX */
  92         struct timeb _gtime;
  93         time_t matchtime;
  94         unsigned short matchmilli;
  95         register struct timeb *tp = & _gtime;
  96
  97         if (time <= 0) return;
  98         ftime(tp);
  99         matchmilli = tp->millitm + time;
 100         matchtime  = tp->time;
 101         while (matchmilli >= 1000)
 102                 {
 103                 ++matchtime;
 104                 matchmilli -= 1000;
 105                 }
 106
 107         while(1)
 108                 {
 109                 ftime(tp);
 110                 if ((tp->time > matchtime) ||
 111                         ((tp->time == matchtime) && (tp->millitm >= matchmilli)))
 112                         break;
 113                 }
 114         }
 115 #endif
 116 #else not BSD
 117 static napms(time) int time; {} /* do nothing, forget it */
 118 #endif BSD
 119 #endif SYSV
 120 #endif NONAP