Proposed changes to asctime.c, zdump.c, and localtime.c

[Olson, Arthur David (NIH/NCI)]

Thanks to Paul and Ken for the feedback on zdump.c. Here's the next
iteration; these changes are relative to the code now available via ftp.

				--ado

------- zdump.c -------
*** /tmp/geta16007	Thu Dec 30 08:46:20 2004
--- /tmp/getb16007	Thu Dec 30 08:46:20 2004
***************
*** 1,4 ****
! static char	elsieid[] = "@(#)zdump.c	7.57";
  
  /*
  ** This code has been made independent of the rest of the time
--- 1,4 ----
! static char	elsieid[] = "@(#)zdump.c	7.59";
  
  /*
  ** This code has been made independent of the rest of the time
***************
*** 151,156 ****
--- 151,157 ----
  static time_t	hunt P((char * name, time_t lot, time_t	hit));
  static void	setabsolutes();
  static void	show P((char * zone, time_t t, int v));
+ static const char *	tformat P((void));
  static time_t	yeartot P((long y));
  
  int
***************
*** 469,475 ****
  	if (v) {
  		tmp = gmtime(&t);
  		if (tmp == NULL) {
! 			(void) printf("%g", (double) t);
  		} else {
  			dumptime(tmp);
  			(void) printf(" UTC");
--- 470,476 ----
  	if (v) {
  		tmp = gmtime(&t);
  		if (tmp == NULL) {
! 			(void) printf(tformat(), t);
  		} else {
  			dumptime(tmp);
  			(void) printf(" UTC");
***************
*** 504,509 ****
--- 505,537 ----
  	return (result == NULL) ? &nada : result;
  }
  
+ /*
+ ** The code below can fail on certain theoretical systems;
+ ** it works on all known real-world systems as of 2004-12-30.
+ */
+ 
+ static const char *
+ tformat()
+ {
+ 	if (0.5 == (time_t) 0.5) {	/* floating */
+ 		if (sizeof (time_t) > sizeof (double))
+ 			return "%Lg";
+ 		return "%g";
+ 	}
+ 	if (0 > (time_t) -1) {		/* signed */
+ 		if (sizeof (time_t) > sizeof (long))
+ 			return "%lld";
+ 		if (sizeof (time_t) > sizeof (int))
+ 			return "%ld";
+ 		return "%d";
+ 	}
+ 	if (sizeof (time_t) > sizeof (unsigned long))
+ 		return "%llu";
+ 	if (sizeof (time_t) > sizeof (unsigned int))
+ 		return "%lu";
+ 	return "%u";
+ }
+ 
  static void
  dumptime(timeptr)
  register const struct tm *	timeptr;