michael@0: /*
michael@0: ** This file is in the public domain, so clarified as of
michael@0: ** 1996-06-05 by Arthur David Olson.
michael@0: */
michael@0: 
michael@0: /*
michael@0: ** Avoid the temptation to punt entirely to strftime;
michael@0: ** the output of strftime is supposed to be locale specific
michael@0: ** whereas the output of asctime is supposed to be constant.
michael@0: */
michael@0: 
michael@0: #ifndef lint
michael@0: #ifndef NOID
michael@0: static char	elsieid[] = "@(#)asctime.c	8.2";
michael@0: #endif /* !defined NOID */
michael@0: #endif /* !defined lint */
michael@0: 
michael@0: /*LINTLIBRARY*/
michael@0: 
michael@0: #include "private.h"
michael@0: #include "tzfile.h"
michael@0: 
michael@0: /*
michael@0: ** Some systems only handle "%.2d"; others only handle "%02d";
michael@0: ** "%02.2d" makes (most) everybody happy.
michael@0: ** At least some versions of gcc warn about the %02.2d;
michael@0: ** we conditionalize below to avoid the warning.
michael@0: */
michael@0: /*
michael@0: ** All years associated with 32-bit time_t values are exactly four digits long;
michael@0: ** some years associated with 64-bit time_t values are not.
michael@0: ** Vintage programs are coded for years that are always four digits long
michael@0: ** and may assume that the newline always lands in the same place.
michael@0: ** For years that are less than four digits, we pad the output with
michael@0: ** leading zeroes to get the newline in the traditional place.
michael@0: ** The -4 ensures that we get four characters of output even if
michael@0: ** we call a strftime variant that produces fewer characters for some years.
michael@0: ** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
michael@0: ** but many implementations pad anyway; most likely the standards are buggy.
michael@0: */
michael@0: #ifdef __GNUC__
michael@0: #define ASCTIME_FMT	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
michael@0: #else /* !defined __GNUC__ */
michael@0: #define ASCTIME_FMT	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
michael@0: #endif /* !defined __GNUC__ */
michael@0: /*
michael@0: ** For years that are more than four digits we put extra spaces before the year
michael@0: ** so that code trying to overwrite the newline won't end up overwriting
michael@0: ** a digit within a year and truncating the year (operating on the assumption
michael@0: ** that no output is better than wrong output).
michael@0: */
michael@0: #ifdef __GNUC__
michael@0: #define ASCTIME_FMT_B	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d     %s\n"
michael@0: #else /* !defined __GNUC__ */
michael@0: #define ASCTIME_FMT_B	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d     %s\n"
michael@0: #endif /* !defined __GNUC__ */
michael@0: 
michael@0: #define STD_ASCTIME_BUF_SIZE	26
michael@0: /*
michael@0: ** Big enough for something such as
michael@0: ** ??? ???-2147483648 -2147483648:-2147483648:-2147483648     -2147483648\n
michael@0: ** (two three-character abbreviations, five strings denoting integers,
michael@0: ** seven explicit spaces, two explicit colons, a newline,
michael@0: ** and a trailing ASCII nul).
michael@0: ** The values above are for systems where an int is 32 bits and are provided
michael@0: ** as an example; the define below calculates the maximum for the system at
michael@0: ** hand.
michael@0: */
michael@0: #define MAX_ASCTIME_BUF_SIZE	(2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)
michael@0: 
michael@0: static char	buf_asctime[MAX_ASCTIME_BUF_SIZE];
michael@0: 
michael@0: /*
michael@0: ** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
michael@0: */
michael@0: 
michael@0: char *
michael@0: asctime_r(timeptr, buf)
michael@0: register const struct tm *	timeptr;
michael@0: char *				buf;
michael@0: {
michael@0: 	static const char	wday_name[][3] = {
michael@0: 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
michael@0: 	};
michael@0: 	static const char	mon_name[][3] = {
michael@0: 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
michael@0: 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
michael@0: 	};
michael@0: 	register const char *	wn;
michael@0: 	register const char *	mn;
michael@0: 	char			year[INT_STRLEN_MAXIMUM(int) + 2];
michael@0: 	char			result[MAX_ASCTIME_BUF_SIZE];
michael@0: 
michael@0: 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
michael@0: 		wn = "???";
michael@0: 	else	wn = wday_name[timeptr->tm_wday];
michael@0: 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
michael@0: 		mn = "???";
michael@0: 	else	mn = mon_name[timeptr->tm_mon];
michael@0: 	/*
michael@0: 	** Use strftime's %Y to generate the year, to avoid overflow problems
michael@0: 	** when computing timeptr->tm_year + TM_YEAR_BASE.
michael@0: 	** Assume that strftime is unaffected by other out-of-range members
michael@0: 	** (e.g., timeptr->tm_mday) when processing "%Y".
michael@0: 	*/
michael@0: 	(void) strftime(year, sizeof year, "%Y", timeptr);
michael@0: 	/*
michael@0: 	** We avoid using snprintf since it's not available on all systems.
michael@0: 	*/
michael@0: 	(void) sprintf(result,
michael@0: 		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
michael@0: 		wn, mn,
michael@0: 		timeptr->tm_mday, timeptr->tm_hour,
michael@0: 		timeptr->tm_min, timeptr->tm_sec,
michael@0: 		year);
michael@0: 	if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime) {
michael@0: 		(void) strcpy(buf, result);
michael@0: 		return buf;
michael@0: 	} else {
michael@0: #ifdef EOVERFLOW
michael@0: 		errno = EOVERFLOW;
michael@0: #else /* !defined EOVERFLOW */
michael@0: 		errno = EINVAL;
michael@0: #endif /* !defined EOVERFLOW */
michael@0: 		return NULL;
michael@0: 	}
michael@0: }
michael@0: 
michael@0: /*
michael@0: ** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
michael@0: */
michael@0: 
michael@0: char *
michael@0: asctime(timeptr)
michael@0: register const struct tm *	timeptr;
michael@0: {
michael@0: 	return asctime_r(timeptr, buf_asctime);
michael@0: }