xref: /dragonfly/lib/libc/stdtime/tzfile.h (revision a414d005c93e85cb42866b5e8feb5f5cec1a82ee)
1 #ifndef TZFILE_H
2 #define TZFILE_H
3 
4 
5 /*
6 ** This file is in the public domain, so clarified as of
7 ** 1996-06-05 by Arthur David Olson.
8 **
9 ** $FreeBSD: head/contrib/tzcode/stdtime/tzfile.h 192625 2009-05-23 06:31:50Z edwin $
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 
42 struct 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 TRUE, transition
68 **                                                time is standard time, if FALSE,
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 TRUE, transition
73 **                                                time is UT, if FALSE,
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          1200
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 #define SECSPERMIN  60
120 #define MINSPERHOUR 60
121 #define HOURSPERDAY 24
122 #define DAYSPERWEEK 7
123 #define DAYSPERNYEAR          365
124 #define DAYSPERLYEAR          366
125 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
126 #define SECSPERDAY  ((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
127 #define MONSPERYEAR 12
128 
129 #define TM_SUNDAY   0
130 #define TM_MONDAY   1
131 #define TM_TUESDAY  2
132 #define TM_WEDNESDAY          3
133 #define TM_THURSDAY 4
134 #define TM_FRIDAY   5
135 #define TM_SATURDAY 6
136 
137 #define TM_JANUARY  0
138 #define TM_FEBRUARY 1
139 #define TM_MARCH    2
140 #define TM_APRIL    3
141 #define TM_MAY                4
142 #define TM_JUNE               5
143 #define TM_JULY               6
144 #define TM_AUGUST   7
145 #define TM_SEPTEMBER          8
146 #define TM_OCTOBER  9
147 #define TM_NOVEMBER 10
148 #define TM_DECEMBER 11
149 
150 #define TM_YEAR_BASE          1900
151 
152 #define EPOCH_YEAR  1970
153 #define EPOCH_WDAY  TM_THURSDAY
154 
155 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
156 
157 /*
158 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that
159 **        isleap(y) == isleap(y % 400)
160 ** and so
161 **        isleap(a + b) == isleap((a + b) % 400)
162 ** or
163 **        isleap(a + b) == isleap(a % 400 + b % 400)
164 ** This is true even if % means modulo rather than Fortran remainder
165 ** (which is allowed by C89 but not C99).
166 ** We use this to avoid addition overflow problems.
167 */
168 
169 #define isleap_sum(a, b)      isleap((a) % 400 + (b) % 400)
170 
171 #endif /* !defined TZFILE_H */
172