2.11BSD/include/tzfile.h

/*
 *	@(#)tzfile.h	5.2.1 (2.11BSD) 1996/11/29
 */

/*
** Information about time zone files.
*/

			/* Time zone object file directory */
#define	TZDIR		"/usr/share/zoneinfo"
#define	TZDEFAULT	"/etc/localtime"

/*
** Each file begins with. . .
*/

struct tzhead {
	char	tzh_reserved[32];	/* reserved for future use */
	char	tzh_timecnt[4];		/* coded number of transition times */
	char	tzh_typecnt[4];		/* coded number of local time types */
	char	tzh_charcnt[4];		/* coded number of abbr. chars */
};

/*
** . . .followed by. . .
**
**	tzh_timecnt (char [4])s		coded transition times a la time(2)
**	tzh_timecnt (unsigned char)s	types of local time starting at above
**	tzh_typecnt repetitions of
**		one (char [4])		coded GMT offset in seconds
**		one (unsigned char)	used to set tm_isdt
**		one (unsigned char)	that's an abbreviation list index
**	tzh_charcnt (char)s		'\0'-terminated zone abbreviaton strings
*/

/*
** In the current implementation, "tzset()" refuses to deal with files that
** exceed any of the limits below.
*/

/*
** The TZ_MAX_TIMES value below is enough to handle a bit more than a
** year's worth of solar time (corrected daily to the nearest second) or
** 138 years of Pacific Presidential Election time
** (where there are three time zone transitions every fourth year).
*/
#define	TZ_MAX_TIMES	370

#define	NOSOLAR			/* We currently don't handle solar time */

#ifndef	NOSOLAR
#define	TZ_MAX_TYPES	256	/* Limited by what (unsigned char)'s can hold */
#else /* !NOSOLAR */
#define	TZ_MAX_TYPES	10	/* Maximum number of local time types */
#endif /* !NOSOLAR */

#define	TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */

#define	SECS_PER_MIN	60
#define	MINS_PER_HOUR	60
#define	HOURS_PER_DAY	24
#define	DAYS_PER_WEEK	7
#define	DAYS_PER_NYEAR	365
#define	DAYS_PER_LYEAR	366
#define	SECS_PER_HOUR	(SECS_PER_MIN * MINS_PER_HOUR)
#define	SECS_PER_DAY	((long) SECS_PER_HOUR * HOURS_PER_DAY)
#define	MONS_PER_YEAR	12

#define	TM_SUNDAY	0
#define	TM_MONDAY	1
#define	TM_TUESDAY	2
#define	TM_WEDNESDAY	3
#define	TM_THURSDAY	4
#define	TM_FRIDAY	5
#define	TM_SATURDAY	6

#define	TM_JANUARY	0
#define	TM_FEBRUARY	1
#define	TM_MARCH	2
#define	TM_APRIL	3
#define	TM_MAY		4
#define	TM_JUNE		5
#define	TM_JULY		6
#define	TM_AUGUST	7
#define	TM_SEPTEMBER	8
#define	TM_OCTOBER	9
#define	TM_NOVEMBER	10
#define	TM_DECEMBER	11
#define	TM_SUNDAY	0

#define	TM_YEAR_BASE	1900

#define	EPOCH_YEAR	1970
#define	EPOCH_WDAY	TM_THURSDAY

/*
** Accurate only for the past couple of centuries;
** that will probably do.
*/

#define	isleap(y) (((y) % 4) == 0 && ((y) % 100) != 0 || ((y) % 400) == 0)