1/* $NetBSD: tzfile.h,v 1.13 2024/02/17 14:54:47 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 8536 for more details about the following format. */ 37 38/* 39** Each file begins with. . . 40*/ 41 42#define TZ_MAGIC "TZif" 43 44struct 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