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nap.c revision 1.2 
      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
    121