xref: /openbsd/lib/libc/time/tzfile.h (revision b7bd7dbe)
1 /*	$OpenBSD: tzfile.h,v 1.9 2012/09/13 11:14:20 millert Exp $	*/
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 
42 struct tzhead {
43 	char	tzh_magic[4];		/* TZ_MAGIC */
44 	char	tzh_version[1];		/* '\0' or '2' as of 2005 */
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 UTC 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 UTC, 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 
89 /*
90 ** In the current implementation, "tzset()" refuses to deal with files that
91 ** exceed any of the limits below.
92 */
93 
94 #ifndef TZ_MAX_TIMES
95 #define TZ_MAX_TIMES	1200
96 #endif /* !defined TZ_MAX_TIMES */
97 
98 #ifndef TZ_MAX_TYPES
99 #ifndef NOSOLAR
100 #define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
101 #endif /* !defined NOSOLAR */
102 #ifdef NOSOLAR
103 /*
104 ** Must be at least 14 for Europe/Riga as of Jan 12 1995,
105 ** as noted by Earl Chew.
106 */
107 #define TZ_MAX_TYPES	20	/* Maximum number of local time types */
108 #endif /* !defined NOSOLAR */
109 #endif /* !defined TZ_MAX_TYPES */
110 
111 #ifndef TZ_MAX_CHARS
112 #define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
113 				/* (limited by what unsigned chars can hold) */
114 #endif /* !defined TZ_MAX_CHARS */
115 
116 #ifndef TZ_MAX_LEAPS
117 #define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
118 #endif /* !defined TZ_MAX_LEAPS */
119 
120 #define SECSPERMIN	60
121 #define MINSPERHOUR	60
122 #define HOURSPERDAY	24
123 #define DAYSPERWEEK	7
124 #define DAYSPERNYEAR	365
125 #define DAYSPERLYEAR	366
126 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
127 #define SECSPERDAY	((long) SECSPERHOUR * HOURSPERDAY)
128 #define MONSPERYEAR	12
129 
130 #define TM_SUNDAY	0
131 #define TM_MONDAY	1
132 #define TM_TUESDAY	2
133 #define TM_WEDNESDAY	3
134 #define TM_THURSDAY	4
135 #define TM_FRIDAY	5
136 #define TM_SATURDAY	6
137 
138 #define TM_JANUARY	0
139 #define TM_FEBRUARY	1
140 #define TM_MARCH	2
141 #define TM_APRIL	3
142 #define TM_MAY		4
143 #define TM_JUNE		5
144 #define TM_JULY		6
145 #define TM_AUGUST	7
146 #define TM_SEPTEMBER	8
147 #define TM_OCTOBER	9
148 #define TM_NOVEMBER	10
149 #define TM_DECEMBER	11
150 
151 #define TM_YEAR_BASE	1900
152 
153 #define EPOCH_YEAR	1970
154 #define EPOCH_WDAY	TM_THURSDAY
155 
156 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
157 
158 /*
159 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that
160 **	isleap(y) == isleap(y % 400)
161 ** and so
162 **	isleap(a + b) == isleap((a + b) % 400)
163 ** or
164 **	isleap(a + b) == isleap(a % 400 + b % 400)
165 ** This is true even if % means modulo rather than Fortran remainder
166 ** (which is allowed by C89 but not C99).
167 ** We use this to avoid addition overflow problems.
168 */
169 
170 #define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
171 
172 #endif /* !defined TZFILE_H */
173