xref: /openbsd/lib/libc/time/tzfile.h (revision 7b36286a)
1 /*	$OpenBSD: tzfile.h,v 1.8 2007/02/06 19:35:16 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 ** ID
22 */
23 
24 #if 0
25 #ifndef lint
26 #ifndef NOID
27 static char	tzfilehid[] = "@(#)tzfile.h	8.1";
28 #endif /* !defined NOID */
29 #endif /* !defined lint */
30 #endif
31 
32 /*
33 ** Information about time zone files.
34 */
35 
36 #ifndef TZDIR
37 #define TZDIR	"/usr/share/zoneinfo" /* Time zone object file directory */
38 #endif /* !defined TZDIR */
39 
40 #ifndef TZDEFAULT
41 #define TZDEFAULT	"/etc/localtime"
42 #endif /* !defined TZDEFAULT */
43 
44 #ifndef TZDEFRULES
45 #define TZDEFRULES	"posixrules"
46 #endif /* !defined TZDEFRULES */
47 
48 /*
49 ** Each file begins with. . .
50 */
51 
52 #define	TZ_MAGIC	"TZif"
53 
54 struct tzhead {
55 	char	tzh_magic[4];		/* TZ_MAGIC */
56 	char	tzh_version[1];		/* '\0' or '2' as of 2005 */
57 	char	tzh_reserved[15];	/* reserved--must be zero */
58 	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
59 	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
60 	char	tzh_leapcnt[4];		/* coded number of leap seconds */
61 	char	tzh_timecnt[4];		/* coded number of transition times */
62 	char	tzh_typecnt[4];		/* coded number of local time types */
63 	char	tzh_charcnt[4];		/* coded number of abbr. chars */
64 };
65 
66 /*
67 ** . . .followed by. . .
68 **
69 **	tzh_timecnt (char [4])s		coded transition times a la time(2)
70 **	tzh_timecnt (unsigned char)s	types of local time starting at above
71 **	tzh_typecnt repetitions of
72 **		one (char [4])		coded UTC offset in seconds
73 **		one (unsigned char)	used to set tm_isdst
74 **		one (unsigned char)	that's an abbreviation list index
75 **	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
76 **	tzh_leapcnt repetitions of
77 **		one (char [4])		coded leap second transition times
78 **		one (char [4])		total correction after above
79 **	tzh_ttisstdcnt (char)s		indexed by type; if TRUE, transition
80 **					time is standard time, if FALSE,
81 **					transition time is wall clock time
82 **					if absent, transition times are
83 **					assumed to be wall clock time
84 **	tzh_ttisgmtcnt (char)s		indexed by type; if TRUE, transition
85 **					time is UTC, if FALSE,
86 **					transition time is local time
87 **					if absent, transition times are
88 **					assumed to be local time
89 */
90 
91 /*
92 ** If tzh_version is '2' or greater, the above is followed by a second instance
93 ** of tzhead and a second instance of the data in which each coded transition
94 ** time uses 8 rather than 4 chars,
95 ** then a POSIX-TZ-environment-variable-style string for use in handling
96 ** instants after the last transition time stored in the file
97 ** (with nothing between the newlines if there is no POSIX representation for
98 ** such instants).
99 */
100 
101 /*
102 ** In the current implementation, "tzset()" refuses to deal with files that
103 ** exceed any of the limits below.
104 */
105 
106 #ifndef TZ_MAX_TIMES
107 #define TZ_MAX_TIMES	1200
108 #endif /* !defined TZ_MAX_TIMES */
109 
110 #ifndef TZ_MAX_TYPES
111 #ifndef NOSOLAR
112 #define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
113 #endif /* !defined NOSOLAR */
114 #ifdef NOSOLAR
115 /*
116 ** Must be at least 14 for Europe/Riga as of Jan 12 1995,
117 ** as noted by Earl Chew.
118 */
119 #define TZ_MAX_TYPES	20	/* Maximum number of local time types */
120 #endif /* !defined NOSOLAR */
121 #endif /* !defined TZ_MAX_TYPES */
122 
123 #ifndef TZ_MAX_CHARS
124 #define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
125 				/* (limited by what unsigned chars can hold) */
126 #endif /* !defined TZ_MAX_CHARS */
127 
128 #ifndef TZ_MAX_LEAPS
129 #define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
130 #endif /* !defined TZ_MAX_LEAPS */
131 
132 #define SECSPERMIN	60
133 #define MINSPERHOUR	60
134 #define HOURSPERDAY	24
135 #define DAYSPERWEEK	7
136 #define DAYSPERNYEAR	365
137 #define DAYSPERLYEAR	366
138 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
139 #define SECSPERDAY	((long) SECSPERHOUR * HOURSPERDAY)
140 #define MONSPERYEAR	12
141 
142 #define TM_SUNDAY	0
143 #define TM_MONDAY	1
144 #define TM_TUESDAY	2
145 #define TM_WEDNESDAY	3
146 #define TM_THURSDAY	4
147 #define TM_FRIDAY	5
148 #define TM_SATURDAY	6
149 
150 #define TM_JANUARY	0
151 #define TM_FEBRUARY	1
152 #define TM_MARCH	2
153 #define TM_APRIL	3
154 #define TM_MAY		4
155 #define TM_JUNE		5
156 #define TM_JULY		6
157 #define TM_AUGUST	7
158 #define TM_SEPTEMBER	8
159 #define TM_OCTOBER	9
160 #define TM_NOVEMBER	10
161 #define TM_DECEMBER	11
162 
163 #define TM_YEAR_BASE	1900
164 
165 #define EPOCH_YEAR	1970
166 #define EPOCH_WDAY	TM_THURSDAY
167 
168 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
169 
170 /*
171 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that
172 **	isleap(y) == isleap(y % 400)
173 ** and so
174 **	isleap(a + b) == isleap((a + b) % 400)
175 ** or
176 **	isleap(a + b) == isleap(a % 400 + b % 400)
177 ** This is true even if % means modulo rather than Fortran remainder
178 ** (which is allowed by C89 but not C99).
179 ** We use this to avoid addition overflow problems.
180 */
181 
182 #define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
183 
184 #endif /* !defined TZFILE_H */
185