1/* Layout and location of TZif files. */
2
3#ifndef TZFILE_H
4
5#define TZFILE_H
6
7/*
8** This file is in the public domain, so clarified as of
9** 1996-06-05 by Arthur David Olson.
10*/
11
12/*
13** This header is for use ONLY with the time conversion code.
14** There is no guarantee that it will remain unchanged,
15** or that it will remain at all.
16** Do NOT copy it to any system include directory.
17** Thank you!
18*/
19
20/*
21** Information about time zone files.
22*/
23
24#ifndef TZDIR
25#define TZDIR "/usr/share/zoneinfo" /* Time zone object file directory */
26#endif /* !defined TZDIR */
27
28#ifndef TZDEFAULT
29#define TZDEFAULT "/etc/localtime"
30#endif /* !defined TZDEFAULT */
31
32#ifndef TZDEFRULES
33#define TZDEFRULES "posixrules"
34#endif /* !defined TZDEFRULES */
35
36/*
37** Each file begins with. . .
38*/
39
40#define TZ_MAGIC "TZif"
41
42struct tzhead {
43 char tzh_magic[4]; /* TZ_MAGIC */
44 char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
45 char tzh_reserved[15]; /* reserved; must be zero */
46 char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */
47 char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
48 char tzh_leapcnt[4]; /* coded number of leap seconds */
49 char tzh_timecnt[4]; /* coded number of transition times */
50 char tzh_typecnt[4]; /* coded number of local time types */
51 char tzh_charcnt[4]; /* coded number of abbr. chars */
52};
53
54/*
55** . . .followed by. . .
56**
57** tzh_timecnt (char [4])s coded transition times a la time(2)
58** tzh_timecnt (unsigned char)s types of local time starting at above
59** tzh_typecnt repetitions of
60** one (char [4]) coded UT offset in seconds
61** one (unsigned char) used to set tm_isdst
62** one (unsigned char) that's an abbreviation list index
63** tzh_charcnt (char)s '\0'-terminated zone abbreviations
64** tzh_leapcnt repetitions of
65** one (char [4]) coded leap second transition times
66** one (char [4]) total correction after above
67** tzh_ttisstdcnt (char)s indexed by type; if 1, transition
68** time is standard time, if 0,
69** transition time is wall clock time
70** if absent, transition times are
71** assumed to be wall clock time
72** tzh_ttisgmtcnt (char)s indexed by type; if 1, transition
73** time is UT, if 0,
74** transition time is local time
75** if absent, transition times are
76** assumed to be local time
77*/
78
79/*
80** If tzh_version is '2' or greater, the above is followed by a second instance
81** of tzhead and a second instance of the data in which each coded transition
82** time uses 8 rather than 4 chars,
83** then a POSIX-TZ-environment-variable-style string for use in handling
84** instants after the last transition time stored in the file
85** (with nothing between the newlines if there is no POSIX representation for
86** such instants).
87**
88** If tz_version is '3' or greater, the above is extended as follows.
89** First, the POSIX TZ string's hour offset may range from -167
90** through 167 as compared to the POSIX-required 0 through 24.
91** Second, its DST start time may be January 1 at 00:00 and its stop
92** time December 31 at 24:00 plus the difference between DST and
93** standard time, indicating DST all year.
94*/
95
96/*
97** In the current implementation, "tzset()" refuses to deal with files that
98** exceed any of the limits below.
99*/
100
101#ifndef TZ_MAX_TIMES
102#define TZ_MAX_TIMES 2000
103#endif /* !defined TZ_MAX_TIMES */
104
105#ifndef TZ_MAX_TYPES
106/* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
107#define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
108#endif /* !defined TZ_MAX_TYPES */
109
110#ifndef TZ_MAX_CHARS
111#define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
112 /* (limited by what unsigned chars can hold) */
113#endif /* !defined TZ_MAX_CHARS */
114
115#ifndef TZ_MAX_LEAPS
116#define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
117#endif /* !defined TZ_MAX_LEAPS */
118
119#endif /* !defined TZFILE_H */
120