xref: /dragonfly/lib/libc/stdtime/tzfile.h (revision 25a2db75)
1 #ifndef TZFILE_H
2 
3 #define TZFILE_H
4 
5 /*
6 ** This file is in the public domain, so clarified as of
7 ** 1996-06-05 by Arthur David Olson.
8 */
9 
10 /*
11 ** This header is for use ONLY with the time conversion code.
12 ** There is no guarantee that it will remain unchanged,
13 ** or that it will remain at all.
14 ** Do NOT copy it to any system include directory.
15 ** Thank you!
16 */
17 
18 /*
19 ** Information about time zone files.
20 */
21 
22 #ifndef TZDIR
23 #define TZDIR	"/usr/share/zoneinfo" /* Time zone object file directory */
24 #endif /* !defined TZDIR */
25 
26 #ifndef TZDEFAULT
27 #define TZDEFAULT	"/etc/localtime"
28 #endif /* !defined TZDEFAULT */
29 
30 #ifndef TZDEFRULES
31 #define TZDEFRULES	"posixrules"
32 #endif /* !defined TZDEFRULES */
33 
34 /*
35 ** Each file begins with. . .
36 */
37 
38 #define	TZ_MAGIC	"TZif"
39 
40 struct tzhead {
41 	char	tzh_magic[4];		/* TZ_MAGIC */
42 	char	tzh_version[1];		/* '\0' or '2' as of 2005 */
43 	char	tzh_reserved[15];	/* reserved--must be zero */
44 	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
45 	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
46 	char	tzh_leapcnt[4];		/* coded number of leap seconds */
47 	char	tzh_timecnt[4];		/* coded number of transition times */
48 	char	tzh_typecnt[4];		/* coded number of local time types */
49 	char	tzh_charcnt[4];		/* coded number of abbr. chars */
50 };
51 
52 /*
53 ** . . .followed by. . .
54 **
55 **	tzh_timecnt (char [4])s		coded transition times a la time(2)
56 **	tzh_timecnt (unsigned char)s	types of local time starting at above
57 **	tzh_typecnt repetitions of
58 **		one (char [4])		coded UTC offset in seconds
59 **		one (unsigned char)	used to set tm_isdst
60 **		one (unsigned char)	that's an abbreviation list index
61 **	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
62 **	tzh_leapcnt repetitions of
63 **		one (char [4])		coded leap second transition times
64 **		one (char [4])		total correction after above
65 **	tzh_ttisstdcnt (char)s		indexed by type; if TRUE, transition
66 **					time is standard time, if FALSE,
67 **					transition time is wall clock time
68 **					if absent, transition times are
69 **					assumed to be wall clock time
70 **	tzh_ttisgmtcnt (char)s		indexed by type; if TRUE, transition
71 **					time is UTC, if FALSE,
72 **					transition time is local time
73 **					if absent, transition times are
74 **					assumed to be local time
75 */
76 
77 /*
78 ** If tzh_version is '2' or greater, the above is followed by a second instance
79 ** of tzhead and a second instance of the data in which each coded transition
80 ** time uses 8 rather than 4 chars,
81 ** then a POSIX-TZ-environment-variable-style string for use in handling
82 ** instants after the last transition time stored in the file
83 ** (with nothing between the newlines if there is no POSIX representation for
84 ** such instants).
85 */
86 
87 /*
88 ** In the current implementation, "tzset()" refuses to deal with files that
89 ** exceed any of the limits below.
90 */
91 
92 #ifndef TZ_MAX_TIMES
93 #define TZ_MAX_TIMES	1200
94 #endif /* !defined TZ_MAX_TIMES */
95 
96 #ifndef TZ_MAX_TYPES
97 #ifndef NOSOLAR
98 #define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
99 #endif /* !defined NOSOLAR */
100 #ifdef NOSOLAR
101 /*
102 ** Must be at least 14 for Europe/Riga as of Jan 12 1995,
103 ** as noted by Earl Chew.
104 */
105 #define TZ_MAX_TYPES	20	/* Maximum number of local time types */
106 #endif /* !defined NOSOLAR */
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	((long) 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