111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/* Layout and location of TZif files. */
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#ifndef TZFILE_H
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#define TZFILE_H
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/*
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* This file is in the public domain, so clarified as of
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* 1996-06-05 by Arthur David Olson.
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*
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* IDENTIFICATION
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* src/timezone/tzfile.h
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*/
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/*
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* This header is for use ONLY with the time conversion code.
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* There is no guarantee that it will remain unchanged,
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* or that it will remain at all.
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* Do NOT copy it to any system include directory.
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* Thank you!
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*/
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/*
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* Information about time zone files.
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*/
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#define TZDEFAULT "/etc/localtime"
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#define TZDEFRULES "posixrules"
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/* See Internet RFC 8536 for more details about the following format. */
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/*
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* Each file begins with. . .
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*/
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#define TZ_MAGIC "TZif"
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struct tzhead
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{
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char tzh_magic[4]; /* TZ_MAGIC */
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char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
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char tzh_reserved[15]; /* reserved; must be zero */
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char tzh_ttisutcnt[4]; /* coded number of trans. time flags */
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char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
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char tzh_leapcnt[4]; /* coded number of leap seconds */
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char tzh_timecnt[4]; /* coded number of transition times */
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char tzh_typecnt[4]; /* coded number of local time types */
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char tzh_charcnt[4]; /* coded number of abbr. chars */
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};
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/*
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* . . .followed by. . .
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*
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* tzh_timecnt (char [4])s coded transition times a la time(2)
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* tzh_timecnt (unsigned char)s types of local time starting at above
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* tzh_typecnt repetitions of
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* one (char [4]) coded UT offset in seconds
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* one (unsigned char) used to set tm_isdst
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* one (unsigned char) that's an abbreviation list index
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* tzh_charcnt (char)s '\0'-terminated zone abbreviations
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* tzh_leapcnt repetitions of
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* one (char [4]) coded leap second transition times
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* one (char [4]) total correction after above
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* tzh_ttisstdcnt (char)s indexed by type; if 1, transition
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* time is standard time, if 0,
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* transition time is local (wall clock)
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* time; if absent, transition times are
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* assumed to be local time
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* tzh_ttisutcnt (char)s indexed by type; if 1, transition
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* time is UT, if 0, transition time is
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* local time; if absent, transition
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* times are assumed to be local time.
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* When this is 1, the corresponding
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* std/wall indicator must also be 1.
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*/
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/*
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* If tzh_version is '2' or greater, the above is followed by a second instance
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* of tzhead and a second instance of the data in which each coded transition
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* time uses 8 rather than 4 chars,
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* then a POSIX-TZ-environment-variable-style string for use in handling
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* instants after the last transition time stored in the file
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* (with nothing between the newlines if there is no POSIX representation for
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* such instants).
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*
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* If tz_version is '3' or greater, the above is extended as follows.
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* First, the POSIX TZ string's hour offset may range from -167
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* through 167 as compared to the POSIX-required 0 through 24.
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* Second, its DST start time may be January 1 at 00:00 and its stop
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* time December 31 at 24:00 plus the difference between DST and
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* standard time, indicating DST all year.
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*/
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/*
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* In the current implementation, "tzset()" refuses to deal with files that
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* exceed any of the limits below.
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*/
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#define TZ_MAX_TIMES 2000
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/* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
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#define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
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#define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
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/* (limited by what unsigned chars can hold) */
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#define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
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#endif /* !defined TZFILE_H */
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