usr/src/include/tzfile.h

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Arthur Olson.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *      @(#)tzfile.h    5.3 (Berkeley) %G%
 */

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

#define TZDIR           "/etc/zoneinfo" /* Time zone object file directory */
#define TZDEFAULT       "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)