xref: /dragonfly/lib/libc/stdtime/tzfile.h (revision a414d005)
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