1  /* Layout and location of TZif files.  */
       2  
       3  #ifndef TZFILE_H
       4  
       5  #define TZFILE_H
       6  
       7  /*
       8  ** This file is in the public domain, so clarified as of
       9  ** 1996-06-05 by Arthur David Olson.
      10  */
      11  
      12  /*
      13  ** This header is for use ONLY with the time conversion code.
      14  ** There is no guarantee that it will remain unchanged,
      15  ** or that it will remain at all.
      16  ** Do NOT copy it to any system include directory.
      17  ** Thank you!
      18  */
      19  
      20  /*
      21  ** Information about time zone files.
      22  */
      23  
      24  #ifndef TZDIR
      25  #define TZDIR	"/usr/share/zoneinfo" /* Time zone object file directory */
      26  #endif /* !defined TZDIR */
      27  
      28  #ifndef TZDEFAULT
      29  #define TZDEFAULT	"/etc/localtime"
      30  #endif /* !defined TZDEFAULT */
      31  
      32  #ifndef TZDEFRULES
      33  #define TZDEFRULES	"posixrules"
      34  #endif /* !defined TZDEFRULES */
      35  
      36  
      37  /* See Internet RFC 8536 for more details about the following format.  */
      38  
      39  /*
      40  ** Each file begins with. . .
      41  */
      42  
      43  #define	TZ_MAGIC	"TZif"
      44  
      45  struct tzhead {
      46  	char	tzh_magic[4];		/* TZ_MAGIC */
      47  	char	tzh_version[1];		/* '\0' or '2' or '3' as of 2013 */
      48  	char	tzh_reserved[15];	/* reserved; must be zero */
      49  	char	tzh_ttisutcnt[4];	/* coded number of trans. time flags */
      50  	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
      51  	char	tzh_leapcnt[4];		/* coded number of leap seconds */
      52  	char	tzh_timecnt[4];		/* coded number of transition times */
      53  	char	tzh_typecnt[4];		/* coded number of local time types */
      54  	char	tzh_charcnt[4];		/* coded number of abbr. chars */
      55  };
      56  
      57  /*
      58  ** . . .followed by. . .
      59  **
      60  **	tzh_timecnt (char [4])s		coded transition times a la time(2)
      61  **	tzh_timecnt (unsigned char)s	types of local time starting at above
      62  **	tzh_typecnt repetitions of
      63  **		one (char [4])		coded UT offset in seconds
      64  **		one (unsigned char)	used to set tm_isdst
      65  **		one (unsigned char)	that's an abbreviation list index
      66  **	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
      67  **	tzh_leapcnt repetitions of
      68  **		one (char [4])		coded leap second transition times
      69  **		one (char [4])		total correction after above
      70  **	tzh_ttisstdcnt (char)s		indexed by type; if 1, transition
      71  **					time is standard time, if 0,
      72  **					transition time is local (wall clock)
      73  **					time; if absent, transition times are
      74  **					assumed to be local time
      75  **	tzh_ttisutcnt (char)s		indexed by type; if 1, transition
      76  **					time is UT, if 0, transition time is
      77  **					local time; if absent, transition
      78  **					times are assumed to be local time.
      79  **					When this is 1, the corresponding
      80  **					std/wall indicator must also be 1.
      81  */
      82  
      83  /*
      84  ** If tzh_version is '2' or greater, the above is followed by a second instance
      85  ** of tzhead and a second instance of the data in which each coded transition
      86  ** time uses 8 rather than 4 chars,
      87  ** then a POSIX-TZ-environment-variable-style string for use in handling
      88  ** instants after the last transition time stored in the file
      89  ** (with nothing between the newlines if there is no POSIX representation for
      90  ** such instants).
      91  **
      92  ** If tz_version is '3' or greater, the above is extended as follows.
      93  ** First, the POSIX TZ string's hour offset may range from -167
      94  ** through 167 as compared to the POSIX-required 0 through 24.
      95  ** Second, its DST start time may be January 1 at 00:00 and its stop
      96  ** time December 31 at 24:00 plus the difference between DST and
      97  ** standard time, indicating DST all year.
      98  */
      99  
     100  /*
     101  ** In the current implementation, "tzset()" refuses to deal with files that
     102  ** exceed any of the limits below.
     103  */
     104  
     105  #ifndef TZ_MAX_TIMES
     106  #define TZ_MAX_TIMES	2000
     107  #endif /* !defined TZ_MAX_TIMES */
     108  
     109  #ifndef TZ_MAX_TYPES
     110  /* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
     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  #define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
     116  				/* (limited by what unsigned chars can hold) */
     117  #endif /* !defined TZ_MAX_CHARS */
     118  
     119  #ifndef TZ_MAX_LEAPS
     120  #define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
     121  #endif /* !defined TZ_MAX_LEAPS */
     122  
     123  #endif /* !defined TZFILE_H */