6 ** This file is in the public domain, so clarified as of
7 ** 1996-06-05 by Arthur David Olson.
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.
19 ** Information about time zone files.
23 #define TZDIR "/usr/local/etc/zoneinfo" /* Time zone object file directory */
24 #endif /* !defined TZDIR */
27 #define TZDEFAULT "localtime"
28 #endif /* !defined TZDEFAULT */
31 #define TZDEFRULES "posixrules"
32 #endif /* !defined TZDEFRULES */
35 ** Each file begins with. . .
38 #define TZ_MAGIC "TZif"
41 char tzh_magic[4]; /* TZ_MAGIC */
42 char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
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 */
53 ** . . .followed by. . .
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 UT 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 UT, if FALSE,
72 ** transition time is local time
73 ** if absent, transition times are
74 ** assumed to be local time
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
86 ** If tz_version is '3' or greater, the above is extended as follows.
87 ** First, the POSIX TZ string's hour offset may range from -167
88 ** through 167 as compared to the POSIX-required 0 through 24.
89 ** Second, its DST start time may be January 1 at 00:00 and its stop
90 ** time December 31 at 24:00 plus the difference between DST and
91 ** standard time, indicating DST all year.
95 ** In the current implementation, "tzset()" refuses to deal with files that
96 ** exceed any of the limits below.
100 #define TZ_MAX_TIMES 2000
101 #endif /* !defined TZ_MAX_TIMES */
104 /* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
105 #define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
106 #endif /* !defined TZ_MAX_TYPES */
109 #define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
110 /* (limited by what unsigned chars can hold) */
111 #endif /* !defined TZ_MAX_CHARS */
114 #define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
115 #endif /* !defined TZ_MAX_LEAPS */
117 #define SECSPERMIN 60
118 #define MINSPERHOUR 60
119 #define HOURSPERDAY 24
120 #define DAYSPERWEEK 7
121 #define DAYSPERNYEAR 365
122 #define DAYSPERLYEAR 366
123 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
124 #define SECSPERDAY ((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
125 #define MONSPERYEAR 12
130 #define TM_WEDNESDAY 3
131 #define TM_THURSDAY 4
133 #define TM_SATURDAY 6
136 #define TM_FEBRUARY 1
143 #define TM_SEPTEMBER 8
145 #define TM_NOVEMBER 10
146 #define TM_DECEMBER 11
148 #define TM_YEAR_BASE 1900
150 #define EPOCH_YEAR 1970
151 #define EPOCH_WDAY TM_THURSDAY
153 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
156 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that
157 ** isleap(y) == isleap(y % 400)
159 ** isleap(a + b) == isleap((a + b) % 400)
161 ** isleap(a + b) == isleap(a % 400 + b % 400)
162 ** This is true even if % means modulo rather than Fortran remainder
163 ** (which is allowed by C89 but not C99).
164 ** We use this to avoid addition overflow problems.
167 #define isleap_sum(a, b) isleap((a) % 400 + (b) % 400)
169 #endif /* !defined TZFILE_H */