93 lines
4.1 KiB
Plaintext
93 lines
4.1 KiB
Plaintext
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The csv file containing the zone_specs used by the
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boost::local_time::tz_database is intended to be customized by the
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library user. When customizing this file (or creating your own) the
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file must follow a specific format.
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This first line is expected to contain column headings and is therefore
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not processed by the tz_database.
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Each record (line) must have eleven fields. Some of those fields can
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be empty. Every field (even empty ones) must be enclosed in double-quotes.
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Ex:
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"America/Phoenix" <- string enclosed in quotes
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"" <- empty field
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Some fields represent a length of time. The format of these fields must be:
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"{+|-}hh:mm[:ss]" <- length-of-time format
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Where the plus or minus is mandatory and the seconds are optional.
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Since some time zones do not use daylight savings it is not always necessary
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for every field in a zone_spec to contain a value. All zone_specs must have
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at least ID and GMT offset. Zones that use daylight savings must have all
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fields filled except: STD ABBR, STD NAME, DST NAME. You should take note
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that DST ABBR is mandatory for zones that use daylight savings (see field
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descriptions for further details).
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********* Fields and their description/details *********
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* ID
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Contains the identifying string for the zone_spec. Any string will
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do as long as it's unique. No two ID's can be the same.
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* STD ABBR
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* STD NAME
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* DST ABBR
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* DST NAME
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These four are all the names and abbreviations used by the time
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zone being described. While any string will do in these fields,
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care should be taken. These fields hold the strings that will be
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used in the output of many of the local_time classes.
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Ex:
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time_zone nyc = tz_db.time_zone_from_region("America/New_York");
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local_time ny_time(date(2004, Aug, 30), IS_DST, nyc);
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cout << ny_time.to_long_string() << endl;
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// 2004-Aug-30 00:00:00 Eastern Daylight Time
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cout << ny_time.to_short_string() << endl;
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// 2004-Aug-30 00:00:00 EDT
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NOTE: The exact format/function names may vary - see local_time
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documentation for further details.
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* GMT offset
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This is the number of hours added to utc to get the local time
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before any daylight savings adjustments are made. Some examples
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are: America/New_York offset -5 hours, & Africa/Cairo offset +2 hours.
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The format must follow the length-of-time format described above.
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* DST adjustment
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The amount of time added to gmt_offset when daylight savings is in
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effect. The format must follow the length-of-time format described
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above.
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#####################################################################
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##### TODO: more rule capabilities are needed - this portion of #####
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##### the tz_database is incomplete #####
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#####################################################################
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* DST Start Date rule
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This is a specially formatted string that describes the day of year
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in which the transition take place. It holds three fields of it's own,
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separated by semicolons.
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* The first field indicates the "nth" weekday of the month. The
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possible values are: 1 (first), 2 (second), 3 (third),
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4 (fourth), 5 (fifth), and -1 (last).
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* The second field indicates the day-of-week from 0-6 (Sun=0).
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* The third field indicates the month from 1-12 (Jan=1).
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Examples are: "-1;5;9"="Last Friday of September",
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"2;1;3"="Second Monday of March"
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* Start time
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Start time is the number of hours past midnight, on the day of the
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start transition, the transition takes place. More simply put, the
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time of day the transition is made (in 24 hours format). The format
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must follow the length-of-time format described above with the
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exception that it must always be positive.
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* DST End date rule
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See DST Start date rule. The difference here is this is the day
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daylight savings ends (transition to STD).
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* End time
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Same as Start time.
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