xref: /netbsd-src/lib/libc/time/asctime.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: asctime.c,v 1.10 2000/01/22 22:19:21 mycroft Exp $	*/
2 
3 /*
4 ** This file is in the public domain, so clarified as of
5 ** 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
6 */
7 
8 #include <sys/cdefs.h>
9 #ifndef lint
10 #ifndef NOID
11 #if 0
12 static char	elsieid[] = "@(#)asctime.c	7.9";
13 #else
14 __RCSID("$NetBSD: asctime.c,v 1.10 2000/01/22 22:19:21 mycroft Exp $");
15 #endif
16 #endif /* !defined NOID */
17 #endif /* !defined lint */
18 
19 /*LINTLIBRARY*/
20 
21 #include "namespace.h"
22 #include "private.h"
23 #include "tzfile.h"
24 
25 #ifdef __weak_alias
26 __weak_alias(asctime_r,_asctime_r)
27 #endif
28 
29 /*
30 ** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, Second Edition, 1996-07-12.
31 */
32 
33 /*
34 ** Big enough for something such as
35 ** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
36 ** (two three-character abbreviations, five strings denoting integers,
37 ** three explicit spaces, two explicit colons, a newline,
38 ** and a trailing ASCII nul).
39 */
40 #define	ASCTIME_BUFLEN	(3 * 2 + 5 * INT_STRLEN_MAXIMUM(int) + 3 + 2 + 1 + 1)
41 
42 char *
43 asctime_r(timeptr, buf)
44 register const struct tm *	timeptr;
45 char *				buf;
46 {
47 	static const char	wday_name[][3] = {
48 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
49 	};
50 	static const char	mon_name[][3] = {
51 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
52 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
53 	};
54 	register const char *	wn;
55 	register const char *	mn;
56 
57 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
58 		wn = "???";
59 	else	wn = wday_name[timeptr->tm_wday];
60 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
61 		mn = "???";
62 	else	mn = mon_name[timeptr->tm_mon];
63 	/*
64 	** The X3J11-suggested format is
65 	**	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d %d\n"
66 	** Since the .2 in 02.2d is ignored, we drop it.
67 	*/
68 	(void)snprintf(buf,
69 		sizeof (char[ASCTIME_BUFLEN]),
70 		"%.3s %.3s%3d %02d:%02d:%02d %d\n",
71 		wn, mn,
72 		timeptr->tm_mday, timeptr->tm_hour,
73 		timeptr->tm_min, timeptr->tm_sec,
74 		TM_YEAR_BASE + timeptr->tm_year);
75 	return buf;
76 }
77 
78 /*
79 ** A la X3J11, with core dump avoidance.
80 */
81 
82 char *
83 asctime(timeptr)
84 register const struct tm *	timeptr;
85 {
86 	static char		result[ASCTIME_BUFLEN];
87 
88 	return asctime_r(timeptr, result);
89 }
90