1 /* $NetBSD: tzfile.h,v 1.14 2025/01/31 18:23:52 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 /* See Internet RFC 9636 for more details about the following format. */ 37 38 /* 39 ** Each file begins with. . . 40 */ 41 42 #define TZ_MAGIC "TZif" 43 44 struct tzhead { 45 char tzh_magic[4]; /* TZ_MAGIC */ 46 char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */ 47 char tzh_reserved[15]; /* reserved; must be zero */ 48 char tzh_ttisutcnt[4]; /* coded number of trans. time flags */ 49 char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */ 50 char tzh_leapcnt[4]; /* coded number of leap seconds */ 51 char tzh_timecnt[4]; /* coded number of transition times */ 52 char tzh_typecnt[4]; /* coded number of local time types */ 53 char tzh_charcnt[4]; /* coded number of abbr. chars */ 54 }; 55 56 /* 57 ** . . .followed by. . . 58 ** 59 ** tzh_timecnt (char [4])s coded transition times a la time(2) 60 ** tzh_timecnt (unsigned char)s types of local time starting at above 61 ** tzh_typecnt repetitions of 62 ** one (char [4]) coded UT offset in seconds 63 ** one (unsigned char) used to set tm_isdst 64 ** one (unsigned char) that's an abbreviation list index 65 ** tzh_charcnt (char)s '\0'-terminated zone abbreviations 66 ** tzh_leapcnt repetitions of 67 ** one (char [4]) coded leap second transition times 68 ** one (char [4]) total correction after above 69 ** tzh_ttisstdcnt (char)s indexed by type; if 1, transition 70 ** time is standard time, if 0, 71 ** transition time is local (wall clock) 72 ** time; if absent, transition times are 73 ** assumed to be local time 74 ** tzh_ttisutcnt (char)s indexed by type; if 1, transition 75 ** time is UT, if 0, transition time is 76 ** local time; if absent, transition 77 ** times are assumed to be local time. 78 ** When this is 1, the corresponding 79 ** std/wall indicator must also be 1. 80 */ 81 82 /* 83 ** If tzh_version is '2' or greater, the above is followed by a second instance 84 ** of tzhead and a second instance of the data in which each coded transition 85 ** time uses 8 rather than 4 chars, 86 ** then a POSIX-TZ-environment-variable-style string for use in handling 87 ** instants after the last transition time stored in the file 88 ** (with nothing between the newlines if there is no POSIX.1-2017 89 ** representation for such instants). 90 ** 91 ** If tz_version is '3' or greater, the above is extended as follows. 92 ** First, the TZ string's hour offset may range from -167 93 ** through 167 as compared to the POSIX-required 0 through 24. 94 ** Second, its DST start time may be January 1 at 00:00 and its stop 95 ** time December 31 at 24:00 plus the difference between DST and 96 ** standard time, indicating DST all year. 97 */ 98 99 /* 100 ** In the current implementation, "tzset()" refuses to deal with files that 101 ** exceed any of the limits below. 102 */ 103 104 #ifndef TZ_MAX_TIMES 105 /* This must be at least 242 for Europe/London with 'zic -b fat'. */ 106 # define TZ_MAX_TIMES 2000 107 #endif /* !defined TZ_MAX_TIMES */ 108 109 #ifndef TZ_MAX_TYPES 110 /* This must be at least 18 for Europe/Vilnius with 'zic -b fat'. */ 111 # define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */ 112 #endif /* !defined TZ_MAX_TYPES */ 113 114 #ifndef TZ_MAX_CHARS 115 /* This must be at least 40 for America/Anchorage. */ 116 # define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */ 117 /* (limited by what unsigned chars can hold) */ 118 #endif /* !defined TZ_MAX_CHARS */ 119 120 #ifndef TZ_MAX_LEAPS 121 /* This must be at least 27 for leap seconds from 1972 through mid-2023. 122 There's a plan to discontinue leap seconds by 2035. */ 123 # define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */ 124 #endif /* !defined TZ_MAX_LEAPS */ 125 126 #define SECSPERMIN 60 127 #define MINSPERHOUR 60 128 #define HOURSPERDAY 24 129 #define DAYSPERWEEK 7 130 #define DAYSPERNYEAR 365 131 #define DAYSPERLYEAR 366 132 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR) 133 #define SECSPERDAY ((int_fast32_t) SECSPERHOUR * HOURSPERDAY) 134 #define MONSPERYEAR 12 135 #define YEARSPERREPEAT 400 136 137 #define TM_SUNDAY 0 138 #define TM_MONDAY 1 139 #define TM_TUESDAY 2 140 #define TM_WEDNESDAY 3 141 #define TM_THURSDAY 4 142 #define TM_FRIDAY 5 143 #define TM_SATURDAY 6 144 145 #define TM_JANUARY 0 146 #define TM_FEBRUARY 1 147 #define TM_MARCH 2 148 #define TM_APRIL 3 149 #define TM_MAY 4 150 #define TM_JUNE 5 151 #define TM_JULY 6 152 #define TM_AUGUST 7 153 #define TM_SEPTEMBER 8 154 #define TM_OCTOBER 9 155 #define TM_NOVEMBER 10 156 #define TM_DECEMBER 11 157 158 #define TM_YEAR_BASE 1900 159 160 #define EPOCH_YEAR 1970 161 #define EPOCH_WDAY TM_THURSDAY 162 163 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0)) 164 165 /* 166 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that 167 ** isleap(y) == isleap(y % 400) 168 ** and so 169 ** isleap(a + b) == isleap((a + b) % 400) 170 ** or 171 ** isleap(a + b) == isleap(a % 400 + b % 400) 172 ** This is true even if % means modulo rather than Fortran remainder 173 ** (which is allowed by C89 but not C99). 174 ** We use this to avoid addition overflow problems. 175 */ 176 177 #define isleap_sum(a, b) isleap((a) % 400 + (b) % 400) 178 179 #endif /* !defined _TZFILE_H_ */ 180
Indexes created Tue Sep 23 23:09:58 GMT 2025