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Commit	Line	Data
	1	/*
	2	** This file is in the public domain, so clarified as of
	3	** 1996-06-05 by Arthur David Olson.
	4	*/
	5
	6	/*
	7	** Avoid the temptation to punt entirely to strftime;
	8	** the output of strftime is supposed to be locale specific
	9	** whereas the output of asctime is supposed to be constant.
	10	*/
	11
	12	/LINTLIBRARY/
	13
	14	#include "private.h"
	15	#include "tzfile.h"
	16
	17	/*
	18	** Some systems only handle "%.2d"; others only handle "%02d";
	19	** "%02.2d" makes (most) everybody happy.
	20	** At least some versions of gcc warn about the %02.2d;
	21	** we conditionalize below to avoid the warning.
	22	*/
	23	/*
	24	** All years associated with 32-bit time_t values are exactly four digits long;
	25	** some years associated with 64-bit time_t values are not.
	26	** Vintage programs are coded for years that are always four digits long
	27	** and may assume that the newline always lands in the same place.
	28	** For years that are less than four digits, we pad the output with
	29	** leading zeroes to get the newline in the traditional place.
	30	** The -4 ensures that we get four characters of output even if
	31	** we call a strftime variant that produces fewer characters for some years.
	32	** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
	33	** but many implementations pad anyway; most likely the standards are buggy.
	34	*/
	35	#ifdef __GNUC__
	36	#define ASCTIME_FMT "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
	37	#else /* !defined __GNUC__ */
	38	#define ASCTIME_FMT "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
	39	#endif /* !defined __GNUC__ */
	40	/*
	41	** For years that are more than four digits we put extra spaces before the year
	42	** so that code trying to overwrite the newline won't end up overwriting
	43	** a digit within a year and truncating the year (operating on the assumption
	44	** that no output is better than wrong output).
	45	*/
	46	#ifdef __GNUC__
	47	#define ASCTIME_FMT_B "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %s\n"
	48	#else /* !defined __GNUC__ */
	49	#define ASCTIME_FMT_B "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %s\n"
	50	#endif /* !defined __GNUC__ */
	51
	52	#define STD_ASCTIME_BUF_SIZE 26
	53	/*
	54	** Big enough for something such as
	55	** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
	56	** (two three-character abbreviations, five strings denoting integers,
	57	** seven explicit spaces, two explicit colons, a newline,
	58	** and a trailing ASCII nul).
	59	** The values above are for systems where an int is 32 bits and are provided
	60	** as an example; the define below calculates the maximum for the system at
	61	** hand.
	62	*/
	63	#define MAX_ASCTIME_BUF_SIZE (23+5INT_STRLEN_MAXIMUM(int)+7+2+1+1)
	64
	65	static char buf_asctime[MAX_ASCTIME_BUF_SIZE];
	66
	67	/*
	68	** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
	69	*/
	70
	71	char *
	72	asctime_r(register const struct tm timeptr, char buf)
	73	{
	74	static const char wday_name[][3] = {
	75	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
	76	};
	77	static const char mon_name[][3] = {
	78	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
	79	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	80	};
	81	register const char * wn;
	82	register const char * mn;
	83	char year[INT_STRLEN_MAXIMUM(int) + 2];
	84	char result[MAX_ASCTIME_BUF_SIZE];
	85
	86	if (timeptr == NULL) {
	87	errno = EINVAL;
	88	return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
	89	}
	90	if (timeptr->tm_wday < 0 \|\| timeptr->tm_wday >= DAYSPERWEEK)
	91	wn = "???";
	92	else wn = wday_name[timeptr->tm_wday];
	93	if (timeptr->tm_mon < 0 \|\| timeptr->tm_mon >= MONSPERYEAR)
	94	mn = "???";
	95	else mn = mon_name[timeptr->tm_mon];
	96	/*
	97	** Use strftime's %Y to generate the year, to avoid overflow problems
	98	** when computing timeptr->tm_year + TM_YEAR_BASE.
	99	** Assume that strftime is unaffected by other out-of-range members
	100	** (e.g., timeptr->tm_mday) when processing "%Y".
	101	*/
	102	(void) strftime(year, sizeof year, "%Y", timeptr);
	103	/*
	104	** We avoid using snprintf since it's not available on all systems.
	105	*/
	106	(void) sprintf(result,
	107	((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
	108	wn, mn,
	109	timeptr->tm_mday, timeptr->tm_hour,
	110	timeptr->tm_min, timeptr->tm_sec,
	111	year);
	112	if (strlen(result) < STD_ASCTIME_BUF_SIZE \|\| buf == buf_asctime)
	113	return strcpy(buf, result);
	114	else {
	115	#ifdef EOVERFLOW
	116	errno = EOVERFLOW;
	117	#else /* !defined EOVERFLOW */
	118	errno = EINVAL;
	119	#endif /* !defined EOVERFLOW */
	120	return NULL;
	121	}
	122	}
	123
	124	/*
	125	** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
	126	*/
	127
	128	char *
	129	asctime(register const struct tm *timeptr)
	130	{
	131	return asctime_r(timeptr, buf_asctime);
	132	}