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nap.c revision 1.1 
      1 /* nap.c		 Larn is copyrighted 1986 by Noah Morgan. */
      2 #include <signal.h>
      3 #include <sys/types.h>
      4 #ifdef SYSV
      5 #include <sys/times.h>
      6 #else
      7 #ifdef BSD
      8 #include <sys/timeb.h>
      9 #endif BSD
     10 #endif SYSV
     11 
     12 /*
     13  *	routine to take a nap for n milliseconds
     14  */
     15 nap(x)
     16 	register int x;
     17 	{
     18 	if (x<=0) return; /* eliminate chance for infinite loop */
     19 	lflush();
     20 	if (x > 999) sleep(x/1000); else napms(x);
     21 	}
     22 
     23 #ifdef NONAP
     24 napms(x)	/* do nothing */
     25 	int x;
     26 	{
     27 	}
     28 #else NONAP
     29 #ifdef SYSV
     30 /*	napms - sleep for time milliseconds - uses times() */
     31 /* this assumes that times returns a relative time in 60ths of a second */
     32 /* this will do horrible things if your times() returns seconds! */
     33 napms(time)
     34 	int time;
     35 	{
     36 	long matchclock, times();
     37 	struct tms stats;
     38 
     39 	if (time<=0) time=1; /* eliminate chance for infinite loop */
     40 	if ((matchclock = times(&stats)) == -1 || matchclock == 0)
     41 		return;	/* error, or BSD style times() */
     42 	matchclock += (time / 17);		/*17 ms/tic is 1000 ms/sec / 60 tics/sec */
     43 
     44 	while(matchclock < times(&stats))
     45 		;
     46 	}
     47 
     48 #else not SYSV
     49 #ifdef BSD
     50 #ifdef SIGVTALRM
     51 /* This must be BSD 4.2!  */
     52 #include <sys/time.h>
     53 #define bit(_a) (1<<((_a)-1))
     54 
     55 static  nullf()
     56     {
     57     }
     58 
     59 /*	napms - sleep for time milliseconds - uses setitimer() */
     60 napms(time)
     61 	int time;
     62     {
     63     struct itimerval    timeout;
     64     int     (*oldhandler) ();
     65     int     oldsig;
     66 
     67 	if (time <= 0) return;
     68 
     69     timerclear(&timeout.it_interval);
     70     timeout.it_value.tv_sec = time / 1000;
     71     timeout.it_value.tv_usec = (time % 1000) * 1000;
     72 
     73     oldsig = sigblock(bit(SIGALRM));
     74     setitimer(ITIMER_REAL, &timeout, (struct itimerval *)0);
     75     oldhandler = signal(SIGALRM, nullf);
     76     sigpause(oldsig);
     77     signal(SIGALRM, oldhandler);
     78     sigsetmask(oldsig);
     79     }
     80 
     81 #else
     82 /*	napms - sleep for time milliseconds - uses ftime() */
     83 
     84 static napms(time)
     85 	int time;
     86 	{
     87 	/* assumed to be BSD UNIX */
     88 	struct timeb _gtime;
     89 	time_t matchtime;
     90 	unsigned short matchmilli;
     91 	register struct timeb *tp = & _gtime;
     92 
     93 	if (time <= 0) return;
     94 	ftime(tp);
     95 	matchmilli = tp->millitm + time;
     96 	matchtime  = tp->time;
     97 	while (matchmilli >= 1000)
     98 		{
     99 		++matchtime;
    100 		matchmilli -= 1000;
    101 		}
    102 
    103 	while(1)
    104 		{
    105 		ftime(tp);
    106 		if ((tp->time > matchtime) ||
    107 			((tp->time == matchtime) && (tp->millitm >= matchmilli)))
    108 			break;
    109 		}
    110 	}
    111 #endif
    112 #else not BSD
    113 static napms(time) int time; {}	/* do nothing, forget it */
    114 #endif BSD
    115 #endif SYSV
    116 #endif NONAP
    117