tzfile.h revision 1.8 
1/*	$NetBSD: tzfile.h,v 1.8 2015/07/11 16:40:53 christos Exp $	*/
2
3#ifndef _TZFILE_H_
4#define _TZFILE_H_
5
6/*
7** This file is in the public domain, so clarified as of
8** 1996-06-05 by Arthur David Olson.
9*/
10
11/*
12** This header is for use ONLY with the time conversion code.
13** There is no guarantee that it will remain unchanged,
14** or that it will remain at all.
15** Do NOT copy it to any system include directory.
16** Thank you!
17*/
18
19/*
20** Information about time zone files.
21*/
22
23#ifndef TZDIR		/* Time zone object file directory */
24#define TZDIR		"/usr/share/zoneinfo"
25#endif /* !defined TZDIR */
26
27#ifndef TZDEFAULT
28#define TZDEFAULT	"/etc/localtime"
29#endif /* !defined TZDEFAULT */
30
31#ifndef TZDEFRULES
32#define TZDEFRULES	"posixrules"
33#endif /* !defined TZDEFRULES */
34
35/*
36** Each file begins with. . .
37*/
38
39#define	TZ_MAGIC	"TZif"
40
41struct tzhead {
42	char	tzh_magic[4];		/* TZ_MAGIC */
43	char	tzh_version[1];		/* '\0' or '2' or '3' as of 2013 */
44	char	tzh_reserved[15];	/* reserved; must be zero */
45	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
46	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
47	char	tzh_leapcnt[4];		/* coded number of leap seconds */
48	char	tzh_timecnt[4];		/* coded number of transition times */
49	char	tzh_typecnt[4];		/* coded number of local time types */
50	char	tzh_charcnt[4];		/* coded number of abbr. chars */
51};
52
53/*
54** . . .followed by. . .
55**
56**	tzh_timecnt (char [4])s		coded transition times a la time(2)
57**	tzh_timecnt (unsigned char)s	types of local time starting at above
58**	tzh_typecnt repetitions of
59**		one (char [4])		coded UT offset in seconds
60**		one (unsigned char)	used to set tm_isdst
61**		one (unsigned char)	that's an abbreviation list index
62**	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
63**	tzh_leapcnt repetitions of
64**		one (char [4])		coded leap second transition times
65**		one (char [4])		total correction after above
66**	tzh_ttisstdcnt (char)s		indexed by type; if 1, transition
67**					time is standard time, if 0,
68**					transition time is wall clock time
69**					if absent, transition times are
70**					assumed to be wall clock time
71**	tzh_ttisgmtcnt (char)s		indexed by type; if 1, transition
72**					time is UT, if 0,
73**					transition time is local time
74**					if absent, transition times are
75**					assumed to be local time
76*/
77
78/*
79** If tzh_version is '2' or greater, the above is followed by a second instance
80** of tzhead and a second instance of the data in which each coded transition
81** time uses 8 rather than 4 chars,
82** then a POSIX-TZ-environment-variable-style string for use in handling
83** instants after the last transition time stored in the file
84** (with nothing between the newlines if there is no POSIX representation for
85** such instants).
86**
87** If tz_version is '3' or greater, the above is extended as follows.
88** First, the POSIX TZ string's hour offset may range from -167
89** through 167 as compared to the POSIX-required 0 through 24.
90** Second, its DST start time may be January 1 at 00:00 and its stop
91** time December 31 at 24:00 plus the difference between DST and
92** standard time, indicating DST all year.
93*/
94
95/*
96** In the current implementation, "tzset()" refuses to deal with files that
97** exceed any of the limits below.
98*/
99
100#ifndef TZ_MAX_TIMES
101#define TZ_MAX_TIMES	2000
102#endif /* !defined TZ_MAX_TIMES */
103
104#ifndef TZ_MAX_TYPES
105/* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
106#define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
107#endif /* !defined TZ_MAX_TYPES */
108
109#ifndef TZ_MAX_CHARS
110#define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
111				/* (limited by what unsigned chars can hold) */
112#endif /* !defined TZ_MAX_CHARS */
113
114#ifndef TZ_MAX_LEAPS
115#define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
116#endif /* !defined TZ_MAX_LEAPS */
117
118#define SECSPERMIN	60
119#define MINSPERHOUR	60
120#define HOURSPERDAY	24
121#define DAYSPERWEEK	7
122#define DAYSPERNYEAR	365
123#define DAYSPERLYEAR	366
124#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
125#define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
126#define MONSPERYEAR	12
127
128#define TM_SUNDAY	0
129#define TM_MONDAY	1
130#define TM_TUESDAY	2
131#define TM_WEDNESDAY	3
132#define TM_THURSDAY	4
133#define TM_FRIDAY	5
134#define TM_SATURDAY	6
135
136#define TM_JANUARY	0
137#define TM_FEBRUARY	1
138#define TM_MARCH	2
139#define TM_APRIL	3
140#define TM_MAY		4
141#define TM_JUNE		5
142#define TM_JULY		6
143#define TM_AUGUST	7
144#define TM_SEPTEMBER	8
145#define TM_OCTOBER	9
146#define TM_NOVEMBER	10
147#define TM_DECEMBER	11
148
149#define TM_YEAR_BASE	1900
150
151#define EPOCH_YEAR	1970
152#define EPOCH_WDAY	TM_THURSDAY
153
154#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
155
156/*
157** Since everything in isleap is modulo 400 (or a factor of 400), we know that
158**	isleap(y) == isleap(y % 400)
159** and so
160**	isleap(a + b) == isleap((a + b) % 400)
161** or
162**	isleap(a + b) == isleap(a % 400 + b % 400)
163** This is true even if % means modulo rather than Fortran remainder
164** (which is allowed by C89 but not C99).
165** We use this to avoid addition overflow problems.
166*/
167
168#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
169
170#endif /* !defined _TZFILE_H_ */
171