1/*	$NetBSD: tzfile.h,v 1.11 2022/08/16 09:03:04 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 representation for
 89** such instants).
 90**
 91** If tz_version is '3' or greater, the above is extended as follows.
 92** First, the POSIX 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# define TZ_MAX_TIMES 2000
106#endif /* !defined TZ_MAX_TIMES */
107
108#ifndef TZ_MAX_TYPES
109/* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
110# define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
111#endif /* !defined TZ_MAX_TYPES */
112
113#ifndef TZ_MAX_CHARS
114# define TZ_MAX_CHARS 50	/* Maximum number of abbreviation characters */
115				/* (limited by what unsigned chars can hold) */
116#endif /* !defined TZ_MAX_CHARS */
117
118#ifndef TZ_MAX_LEAPS
119# define TZ_MAX_LEAPS 50	/* Maximum number of leap second corrections */
120#endif /* !defined TZ_MAX_LEAPS */
121
122#define SECSPERMIN	60
123#define MINSPERHOUR	60
124#define HOURSPERDAY	24
125#define DAYSPERWEEK	7
126#define DAYSPERNYEAR	365
127#define DAYSPERLYEAR	366
128#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
129#define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
130#define MONSPERYEAR	12
131
132#define TM_SUNDAY	0
133#define TM_MONDAY	1
134#define TM_TUESDAY	2
135#define TM_WEDNESDAY	3
136#define TM_THURSDAY	4
137#define TM_FRIDAY	5
138#define TM_SATURDAY	6
139
140#define TM_JANUARY	0
141#define TM_FEBRUARY	1
142#define TM_MARCH	2
143#define TM_APRIL	3
144#define TM_MAY		4
145#define TM_JUNE		5
146#define TM_JULY		6
147#define TM_AUGUST	7
148#define TM_SEPTEMBER	8
149#define TM_OCTOBER	9
150#define TM_NOVEMBER	10
151#define TM_DECEMBER	11
152
153#define TM_YEAR_BASE	1900
154
155#define EPOCH_YEAR	1970
156#define EPOCH_WDAY	TM_THURSDAY
157
158#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
159
160/*
161** Since everything in isleap is modulo 400 (or a factor of 400), we know that
162**	isleap(y) == isleap(y % 400)
163** and so
164**	isleap(a + b) == isleap((a + b) % 400)
165** or
166**	isleap(a + b) == isleap(a % 400 + b % 400)
167** This is true even if % means modulo rather than Fortran remainder
168** (which is allowed by C89 but not C99).
169** We use this to avoid addition overflow problems.
170*/
171
172#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
173
174#endif /* !defined _TZFILE_H_ */