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 | |
45 | struct 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 | |