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 1, transition
  66 **                                      time is standard time, if 0,
  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 1, transition
  71 **                                      time is UT, if 0,
  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 #endif /* !defined TZFILE_H */