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Diffstat (limited to 'src/third_party/boost-1.60.0/libs/date_time/data/README.zone_spec_csv_file')
-rw-r--r-- | src/third_party/boost-1.60.0/libs/date_time/data/README.zone_spec_csv_file | 92 |
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diff --git a/src/third_party/boost-1.60.0/libs/date_time/data/README.zone_spec_csv_file b/src/third_party/boost-1.60.0/libs/date_time/data/README.zone_spec_csv_file new file mode 100644 index 00000000000..069cac21950 --- /dev/null +++ b/src/third_party/boost-1.60.0/libs/date_time/data/README.zone_spec_csv_file @@ -0,0 +1,92 @@ + +The csv file containing the zone_specs used by the +boost::local_time::tz_database is intended to be customized by the +library user. When customizing this file (or creating your own) the +file must follow a specific format. + +This first line is expected to contain column headings and is therefore +not processed by the tz_database. + +Each record (line) must have eleven fields. Some of those fields can +be empty. Every field (even empty ones) must be enclosed in double-quotes. +Ex: + "America/Phoenix" <- string enclosed in quotes + "" <- empty field + +Some fields represent a length of time. The format of these fields must be: + "{+|-}hh:mm[:ss]" <- length-of-time format +Where the plus or minus is mandatory and the seconds are optional. + +Since some time zones do not use daylight savings it is not always necessary +for every field in a zone_spec to contain a value. All zone_specs must have +at least ID and GMT offset. Zones that use daylight savings must have all +fields filled except: STD ABBR, STD NAME, DST NAME. You should take note +that DST ABBR is mandatory for zones that use daylight savings (see field +descriptions for further details). + + +********* Fields and their description/details ********* + +* ID + Contains the identifying string for the zone_spec. Any string will + do as long as it's unique. No two ID's can be the same. + +* STD ABBR +* STD NAME +* DST ABBR +* DST NAME + These four are all the names and abbreviations used by the time + zone being described. While any string will do in these fields, + care should be taken. These fields hold the strings that will be + used in the output of many of the local_time classes. + Ex: + time_zone nyc = tz_db.time_zone_from_region("America/New_York"); + local_time ny_time(date(2004, Aug, 30), IS_DST, nyc); + cout << ny_time.to_long_string() << endl; + // 2004-Aug-30 00:00:00 Eastern Daylight Time + cout << ny_time.to_short_string() << endl; + // 2004-Aug-30 00:00:00 EDT + + NOTE: The exact format/function names may vary - see local_time + documentation for further details. + +* GMT offset + This is the number of hours added to utc to get the local time + before any daylight savings adjustments are made. Some examples + are: America/New_York offset -5 hours, & Africa/Cairo offset +2 hours. + The format must follow the length-of-time format described above. + +* DST adjustment + The amount of time added to gmt_offset when daylight savings is in + effect. The format must follow the length-of-time format described + above. + +##################################################################### +##### TODO: more rule capabilities are needed - this portion of ##### +##### the tz_database is incomplete ##### +##################################################################### +* DST Start Date rule + This is a specially formatted string that describes the day of year + in which the transition take place. It holds three fields of it's own, + separated by semicolons. + * The first field indicates the "nth" weekday of the month. The + possible values are: 1 (first), 2 (second), 3 (third), + 4 (fourth), 5 (fifth), and -1 (last). + * The second field indicates the day-of-week from 0-6 (Sun=0). + * The third field indicates the month from 1-12 (Jan=1). + + Examples are: "-1;5;9"="Last Friday of September", + "2;1;3"="Second Monday of March" + +* Start time + Start time is the number of hours past midnight, on the day of the + start transition, the transition takes place. More simply put, the + time of day the transition is made (in 24 hours format). The format + must follow the length-of-time format described above with the + exception that it must always be positive. + +* DST End date rule + See DST Start date rule. The difference here is this is the day + daylight savings ends (transition to STD). +* End time + Same as Start time. |