timezone/tzfile.h

   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/local/etc/zoneinfo" /* Time zone object file directory */
  24 #endif /* !defined TZDIR */
  25
  26 #ifndef TZDEFAULT
  27 #define TZDEFAULT       "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' 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 */
  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 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
  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 ** 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.
  92 */
  93
  94 /*
  95 ** In the current implementation, "tzset()" refuses to deal with files that
  96 ** exceed any of the limits below.
  97 */
  98
  99 #ifndef TZ_MAX_TIMES
 100 #define TZ_MAX_TIMES    2000
 101 #endif /* !defined TZ_MAX_TIMES */
 102
 103 #ifndef TZ_MAX_TYPES
 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 */
 107
 108 #ifndef TZ_MAX_CHARS
 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 */
 112
 113 #ifndef TZ_MAX_LEAPS
 114 #define TZ_MAX_LEAPS    50      /* Maximum number of leap second corrections */
 115 #endif /* !defined TZ_MAX_LEAPS */
 116
 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
 126
 127 #define TM_SUNDAY       0
 128 #define TM_MONDAY       1
 129 #define TM_TUESDAY      2
 130 #define TM_WEDNESDAY    3
 131 #define TM_THURSDAY     4
 132 #define TM_FRIDAY       5
 133 #define TM_SATURDAY     6
 134
 135 #define TM_JANUARY      0
 136 #define TM_FEBRUARY     1
 137 #define TM_MARCH        2
 138 #define TM_APRIL        3
 139 #define TM_MAY          4
 140 #define TM_JUNE         5
 141 #define TM_JULY         6
 142 #define TM_AUGUST       7
 143 #define TM_SEPTEMBER    8
 144 #define TM_OCTOBER      9
 145 #define TM_NOVEMBER     10
 146 #define TM_DECEMBER     11
 147
 148 #define TM_YEAR_BASE    1900
 149
 150 #define EPOCH_YEAR      1970
 151 #define EPOCH_WDAY      TM_THURSDAY
 152
 153 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
 154
 155 /*
 156 ** Since everything in isleap is modulo 400 (or a factor of 400), we know that
 157 **      isleap(y) == isleap(y % 400)
 158 ** and so
 159 **      isleap(a + b) == isleap((a + b) % 400)
 160 ** or
 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.
 165 */
 166
 167 #define isleap_sum(a, b)        isleap((a) % 400 + (b) % 400)
 168
 169 #endif /* !defined TZFILE_H */