boost/date_time/local_timezone_defs.hpp
#ifndef DATE_TIME_LOCAL_TIMEZONE_DEFS_HPP__ #define DATE_TIME_LOCAL_TIMEZONE_DEFS_HPP__ /* Copyright (c) 2002,2003 CrystalClear Software, Inc. * Use, modification and distribution is subject to the * Boost Software License, Version 1.0. (See accompanying * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) * Author: Jeff Garland * $Date$ */ #include "boost/date_time/dst_rules.hpp" namespace boost { namespace date_time { // Configurations for common dst rules cases: // See http://www.wharton.co.uk/Support/sup_dst.htm for more // information on how various locales use dst rules //! Specification for daylight savings start rules in US /*! This class is used to configure dst_calc_engine template typically as follows: @code using namespace boost::gregorian; using namespace boost::posix_time; typedef us_dst_trait<date> us_dst_traits; typedef boost::date_time::dst_calc_engine<date, time_duration, us_dst_traits> us_dst_calc; //calculate the 2002 transition day of USA April 7 2002 date dst_start = us_dst_calc::local_dst_start_day(2002); //calculate the 2002 transition day of USA Oct 27 2002 date dst_end = us_dst_calc::local_dst_end_day(2002); //check if a local time is in dst or not -- posible answers //are yes, no, invalid time label, ambiguous ptime t(...some time...); if (us_dst::local_is_dst(t.date(), t.time_of_day()) == boost::date_time::is_not_in_dst) { } @endcode This generates a type suitable for the calculation of dst transitions for the United States. Of course other templates can be used for other locales. */ template<class date_type> struct us_dst_trait { typedef typename date_type::day_of_week_type day_of_week_type; typedef typename date_type::month_type month_type; typedef typename date_type::year_type year_type; typedef date_time::nth_kday_of_month<date_type> start_rule_functor; typedef date_time::first_kday_of_month<date_type> end_rule_functor; typedef date_time::first_kday_of_month<date_type> start_rule_functor_pre2007; typedef date_time::last_kday_of_month<date_type> end_rule_functor_pre2007; static day_of_week_type start_day(year_type) {return Sunday;} static month_type start_month(year_type y) { if (y < 2007) return Apr; return Mar; } static day_of_week_type end_day(year_type) {return Sunday;} static month_type end_month(year_type y) { if (y < 2007) return Oct; return Nov; } static date_type local_dst_start_day(year_type year) { if (year < 2007) { start_rule_functor_pre2007 start1(start_day(year), start_month(year)); return start1.get_date(year); } start_rule_functor start(start_rule_functor::second, start_day(year), start_month(year)); return start.get_date(year); } static date_type local_dst_end_day(year_type year) { if (year < 2007) { end_rule_functor_pre2007 end_rule(end_day(year), end_month(year)); return end_rule.get_date(year); } end_rule_functor end(end_day(year), end_month(year)); return end.get_date(year); } static int dst_start_offset_minutes() { return 120;} static int dst_end_offset_minutes() { return 120; } static int dst_shift_length_minutes() { return 60; } }; //!Rules for daylight savings start in the EU (Last Sun in Mar) /*!These amount to the following: - Start of dst day is last Sunday in March - End day of dst is last Sunday in Oct - Going forward switch time is 2:00 am (offset 120 minutes) - Going back switch time is 3:00 am (off set 180 minutes) - Shift duration is one hour (60 minutes) */ template<class date_type> struct eu_dst_trait { typedef typename date_type::day_of_week_type day_of_week_type; typedef typename date_type::month_type month_type; typedef typename date_type::year_type year_type; typedef date_time::last_kday_of_month<date_type> start_rule_functor; typedef date_time::last_kday_of_month<date_type> end_rule_functor; static day_of_week_type start_day(year_type) {return Sunday;} static month_type start_month(year_type) {return Mar;} static day_of_week_type end_day(year_type) {return Sunday;} static month_type end_month(year_type) {return Oct;} static int dst_start_offset_minutes() { return 120;} static int dst_end_offset_minutes() { return 180; } static int dst_shift_length_minutes() { return 60; } static date_type local_dst_start_day(year_type year) { start_rule_functor start(start_day(year), start_month(year)); return start.get_date(year); } static date_type local_dst_end_day(year_type year) { end_rule_functor end(end_day(year), end_month(year)); return end.get_date(year); } }; //! Alternative dst traits for some parts of the United Kingdom /* Several places in the UK use EU start and end rules for the day, but different local conversion times (eg: forward change at 1:00 am local and backward change at 2:00 am dst instead of 2:00am forward and 3:00am back for the EU). */ template<class date_type> struct uk_dst_trait : public eu_dst_trait<date_type> { static int dst_start_offset_minutes() { return 60;} static int dst_end_offset_minutes() { return 120; } static int dst_shift_length_minutes() { return 60; } }; //Rules for Adelaide Australia template<class date_type> struct acst_dst_trait { typedef typename date_type::day_of_week_type day_of_week_type; typedef typename date_type::month_type month_type; typedef typename date_type::year_type year_type; typedef date_time::last_kday_of_month<date_type> start_rule_functor; typedef date_time::last_kday_of_month<date_type> end_rule_functor; static day_of_week_type start_day(year_type) {return Sunday;} static month_type start_month(year_type) {return Oct;} static day_of_week_type end_day(year_type) {return Sunday;} static month_type end_month(year_type) {return Mar;} static int dst_start_offset_minutes() { return 120;} static int dst_end_offset_minutes() { return 180; } static int dst_shift_length_minutes() { return 60; } static date_type local_dst_start_day(year_type year) { start_rule_functor start(start_day(year), start_month(year)); return start.get_date(year); } static date_type local_dst_end_day(year_type year) { end_rule_functor end(end_day(year), end_month(year)); return end.get_date(year); } }; } } //namespace boost::date_time #endif