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/* See Internet RFC 8536 for more details about the following format. */
38
39/*
40** Each file begins with. . .
41*/
42
43#define TZ_MAGIC "TZif"
44
45struct tzhead {
46 char tzh_magic[4]; /* TZ_MAGIC */
47 char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
48 char tzh_reserved[15]; /* reserved; must be zero */
49 char tzh_ttisutcnt[4]; /* coded number of trans. time flags */
50 char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
51 char tzh_leapcnt[4]; /* coded number of leap seconds */
52 char tzh_timecnt[4]; /* coded number of transition times */
53 char tzh_typecnt[4]; /* coded number of local time types */
54 char tzh_charcnt[4]; /* coded number of abbr. chars */
55};
56
57/*
58** . . .followed by. . .
59**
60** tzh_timecnt (char [4])s coded transition times a la time(2)
61** tzh_timecnt (unsigned char)s types of local time starting at above
62** tzh_typecnt repetitions of
63** one (char [4]) coded UT offset in seconds
64** one (unsigned char) used to set tm_isdst
65** one (unsigned char) that's an abbreviation list index
66** tzh_charcnt (char)s '\0'-terminated zone abbreviations
67** tzh_leapcnt repetitions of
68** one (char [4]) coded leap second transition times
69** one (char [4]) total correction after above
70** tzh_ttisstdcnt (char)s indexed by type; if 1, transition
71** time is standard time, if 0,
72** transition time is local (wall clock)
73** time; if absent, transition times are
74** assumed to be local time
75** tzh_ttisutcnt (char)s indexed by type; if 1, transition
76** time is UT, if 0, transition time is
77** local time; if absent, transition
78** times are assumed to be local time.
79** When this is 1, the corresponding
80** std/wall indicator must also be 1.
81*/
82
83/*
84** If tzh_version is '2' or greater, the above is followed by a second instance
85** of tzhead and a second instance of the data in which each coded transition
86** time uses 8 rather than 4 chars,
87** then a POSIX-TZ-environment-variable-style string for use in handling
88** instants after the last transition time stored in the file
89** (with nothing between the newlines if there is no POSIX representation for
90** such instants).
91**
92** If tz_version is '3' or greater, the above is extended as follows.
93** First, the POSIX TZ string's hour offset may range from -167
94** through 167 as compared to the POSIX-required 0 through 24.
95** Second, its DST start time may be January 1 at 00:00 and its stop
96** time December 31 at 24:00 plus the difference between DST and
97** standard time, indicating DST all year.
98*/
99
100/*
101** In the current implementation, "tzset()" refuses to deal with files that
102** exceed any of the limits below.
103*/
104
105#ifndef TZ_MAX_TIMES
106#define TZ_MAX_TIMES 2000
107#endif /* !defined TZ_MAX_TIMES */
108
109#ifndef TZ_MAX_TYPES
110/* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
111#define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
112#endif /* !defined TZ_MAX_TYPES */
113
114#ifndef TZ_MAX_CHARS
115#define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
116 /* (limited by what unsigned chars can hold) */
117#endif /* !defined TZ_MAX_CHARS */
118
119#ifndef TZ_MAX_LEAPS
120#define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
121#endif /* !defined TZ_MAX_LEAPS */
122
123#endif /* !defined TZFILE_H */
124