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/* Layout and location of TZif files. */
#ifndef TZFILE_H
#define TZFILE_H
/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/
/*
** This header is for use ONLY with the time conversion code.
** There is no guarantee that it will remain unchanged,
** or that it will remain at all.
** Do NOT copy it to any system include directory.
** Thank you!
*/
/*
** Information about time zone files.
*/
#ifndef TZDEFRULES
# define TZDEFRULES "posixrules"
#endif /* !defined TZDEFRULES */
/* See Internet RFC 8536 for more details about the following format. */
/*
** Each file begins with. . .
*/
#define TZ_MAGIC "TZif"
struct tzhead {
char tzh_magic[4]; /* TZ_MAGIC */
char tzh_version[1]; /* '\0' or '2'-'4' as of 2021 */
char tzh_reserved[15]; /* reserved; must be zero */
char tzh_ttisutcnt[4]; /* coded number of trans. time flags */
char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
char tzh_leapcnt[4]; /* coded number of leap seconds */
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 UT offset in seconds
** one (unsigned char) used to set tm_isdst
** one (unsigned char) that's an abbreviation list index
** tzh_charcnt (char)s '\0'-terminated zone abbreviations
** tzh_leapcnt repetitions of
** one (char [4]) coded leap second transition times
** one (char [4]) total correction after above
** tzh_ttisstdcnt (char)s indexed by type; if 1, transition
** time is standard time, if 0,
** transition time is local (wall clock)
** time; if absent, transition times are
** assumed to be local time
** tzh_ttisutcnt (char)s indexed by type; if 1, transition
** time is UT, if 0, transition time is
** local time; if absent, transition
** times are assumed to be local time.
** When this is 1, the corresponding
** std/wall indicator must also be 1.
*/
/*
** If tzh_version is '2' or greater, the above is followed by a second instance
** of tzhead and a second instance of the data in which each coded transition
** time uses 8 rather than 4 chars,
** then a POSIX-TZ-environment-variable-style string for use in handling
** instants after the last transition time stored in the file
** (with nothing between the newlines if there is no POSIX.1-2017
** representation for such instants).
**
** If tz_version is '3' or greater, the above is extended as follows.
** First, the TZ string's hour offset may range from -167
** through 167 as compared to the POSIX-required 0 through 24.
** Second, its DST start time may be January 1 at 00:00 and its stop
** time December 31 at 24:00 plus the difference between DST and
** standard time, indicating DST all year.
*/
/*
** In the current implementation, "tzset()" refuses to deal with files that
** exceed any of the limits below.
*/
#ifndef TZ_MAX_TIMES
/* This must be at least 242 for Europe/London with 'zic -b fat'. */
# define TZ_MAX_TIMES 2000
#endif /* !defined TZ_MAX_TIMES */
#ifndef TZ_MAX_TYPES
/* This must be at least 18 for Europe/Vilnius with 'zic -b fat'. */
# define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
#endif /* !defined TZ_MAX_TYPES */
#ifndef TZ_MAX_CHARS
/* This must be at least 40 for America/Anchorage. */
# define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
/* (limited by what unsigned chars can hold) */
#endif /* !defined TZ_MAX_CHARS */
#ifndef TZ_MAX_LEAPS
/* This must be at least 27 for leap seconds from 1972 through mid-2023.
There's a plan to discontinue leap seconds by 2035. */
# define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
#endif /* !defined TZ_MAX_LEAPS */
#endif /* !defined TZFILE_H */
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