--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ossrv_pub/boost_apis/boost/date_time/dst_rules.hpp Tue Feb 02 02:01:42 2010 +0200
@@ -0,0 +1,391 @@
+#ifndef DATE_TIME_DST_RULES_HPP__
+#define DATE_TIME_DST_RULES_HPP__
+
+/* Copyright (c) 2002,2003, 2007 CrystalClear Software, Inc.
+ * Use, modification and distribution is subject to the
+ * Boost Software License, Version 1.0. (See accompanying
+ * file LICENSE-1.0 or http://www.boost.org/LICENSE-1.0)
+ * Author: Jeff Garland, Bart Garst
+ * $Date: 2007/03/02 01:54:49 $
+ */
+
+/*! @file dst_rules.hpp
+ Contains template class to provide static dst rule calculations
+*/
+
+#include "boost/date_time/date_generators.hpp"
+#include "boost/date_time/period.hpp"
+#include "boost/date_time/date_defs.hpp"
+#include <stdexcept>
+
+namespace boost {
+ namespace date_time {
+
+ enum time_is_dst_result {is_not_in_dst, is_in_dst,
+ ambiguous, invalid_time_label};
+
+
+ //! Dynamic class used to caluclate dst transition information
+ template<class date_type_,
+ class time_duration_type_>
+ class dst_calculator
+ {
+ public:
+ typedef time_duration_type_ time_duration_type;
+ typedef date_type_ date_type;
+
+ //! Check the local time offset when on dst start day
+ /*! On this dst transition, the time label between
+ * the transition boundary and the boudary + the offset
+ * are invalid times. If before the boundary then still
+ * not in dst.
+ *@param time_of_day Time offset in the day for the local time
+ *@param dst_start_offset_minutes Local day offset for start of dst
+ *@param dst_length_minutes Number of minutes to adjust clock forward
+ *@retval status of time label w.r.t. dst
+ */
+ static time_is_dst_result
+ process_local_dst_start_day(const time_duration_type& time_of_day,
+ unsigned int dst_start_offset_minutes,
+ long dst_length_minutes)
+ {
+ //std::cout << "here" << std::endl;
+ if (time_of_day < time_duration_type(0,dst_start_offset_minutes,0)) {
+ return is_not_in_dst;
+ }
+ long offset = dst_start_offset_minutes + dst_length_minutes;
+ if (time_of_day >= time_duration_type(0,offset,0)) {
+ return is_in_dst;
+ }
+ return invalid_time_label;
+ }
+
+ //! Check the local time offset when on the last day of dst
+ /*! This is the calculation for the DST end day. On that day times
+ * prior to the conversion time - dst_length (1 am in US) are still
+ * in dst. Times between the above and the switch time are
+ * ambiguous. Times after the start_offset are not in dst.
+ *@param time_of_day Time offset in the day for the local time
+ *@param dst_end_offset_minutes Local time of day for end of dst
+ *@retval status of time label w.r.t. dst
+ */
+ static time_is_dst_result
+ process_local_dst_end_day(const time_duration_type& time_of_day,
+ unsigned int dst_end_offset_minutes,
+ long dst_length_minutes)
+ {
+ //in US this will be 60 so offset in day is 1,0,0
+ int offset = dst_end_offset_minutes-dst_length_minutes;
+ if (time_of_day < time_duration_type(0,offset,0)) {
+ return is_in_dst;
+ }
+ if (time_of_day >= time_duration_type(0,dst_end_offset_minutes,0)) {
+ return is_not_in_dst;
+ }
+ return ambiguous;
+ }
+
+ //! Calculates if the given local time is dst or not
+ /*! Determines if the time is really in DST or not. Also checks for
+ * invalid and ambiguous.
+ * @param current_day The day to check for dst
+ * @param time_of_day Time offset within the day to check
+ * @param dst_start_day Starting day of dst for the given locality
+ * @param dst_start_offset Time offset within day for dst boundary
+ * @param dst_end_day Ending day of dst for the given locality
+ * @param dst_end_offset Time offset within day given in dst for dst boundary
+ * @param dst_length lenght of dst adjusment
+ * @retval The time is either ambiguous, invalid, in dst, or not in dst
+ */
+ static time_is_dst_result
+ local_is_dst(const date_type& current_day,
+ const time_duration_type& time_of_day,
+ const date_type& dst_start_day,
+ const time_duration_type& dst_start_offset,
+ const date_type& dst_end_day,
+ const time_duration_type& dst_end_offset,
+ const time_duration_type& dst_length_minutes)
+ {
+ unsigned int start_minutes =
+ dst_start_offset.hours() * 60 + dst_start_offset.minutes();
+ unsigned int end_minutes =
+ dst_end_offset.hours() * 60 + dst_end_offset.minutes();
+ long length_minutes =
+ dst_length_minutes.hours() * 60 + dst_length_minutes.minutes();
+
+ return local_is_dst(current_day, time_of_day,
+ dst_start_day, start_minutes,
+ dst_end_day, end_minutes,
+ length_minutes);
+ }
+
+ //! Calculates if the given local time is dst or not
+ /*! Determines if the time is really in DST or not. Also checks for
+ * invalid and ambiguous.
+ * @param current_day The day to check for dst
+ * @param time_of_day Time offset within the day to check
+ * @param dst_start_day Starting day of dst for the given locality
+ * @param dst_start_offset_minutes Offset within day for dst
+ * boundary (eg 120 for US which is 02:00:00)
+ * @param dst_end_day Ending day of dst for the given locality
+ * @param dst_end_offset_minutes Offset within day given in dst for dst
+ * boundary (eg 120 for US which is 02:00:00)
+ * @param dst_length_minutes Length of dst adjusment (eg: 60 for US)
+ * @retval The time is either ambiguous, invalid, in dst, or not in dst
+ */
+ static time_is_dst_result
+ local_is_dst(const date_type& current_day,
+ const time_duration_type& time_of_day,
+ const date_type& dst_start_day,
+ unsigned int dst_start_offset_minutes,
+ const date_type& dst_end_day,
+ unsigned int dst_end_offset_minutes,
+ long dst_length_minutes)
+ {
+ //in northern hemisphere dst is in the middle of the year
+ if (dst_start_day < dst_end_day) {
+ if ((current_day > dst_start_day) && (current_day < dst_end_day)) {
+ return is_in_dst;
+ }
+ if ((current_day < dst_start_day) || (current_day > dst_end_day)) {
+ return is_not_in_dst;
+ }
+ }
+ else {//southern hemisphere dst is at begining /end of year
+ if ((current_day < dst_start_day) && (current_day > dst_end_day)) {
+ return is_not_in_dst;
+ }
+ if ((current_day > dst_start_day) || (current_day < dst_end_day)) {
+ return is_in_dst;
+ }
+ }
+
+ if (current_day == dst_start_day) {
+ return process_local_dst_start_day(time_of_day,
+ dst_start_offset_minutes,
+ dst_length_minutes);
+ }
+
+ if (current_day == dst_end_day) {
+ return process_local_dst_end_day(time_of_day,
+ dst_end_offset_minutes,
+ dst_length_minutes);
+ }
+ //you should never reach this statement
+ return invalid_time_label;
+ }
+
+ };
+
+
+ //! Compile-time configurable daylight savings time calculation engine
+ /* This template provides the ability to configure a daylight savings
+ * calculation at compile time covering all the cases. Unfortunately
+ * because of the number of dimensions related to daylight savings
+ * calculation the number of parameters is high. In addition, the
+ * start and end transition rules are complex types that specify
+ * an algorithm for calculation of the starting day and ending
+ * day of daylight savings time including the month and day
+ * specifications (eg: last sunday in October).
+ *
+ * @param date_type A type that represents dates, typically gregorian::date
+ * @param time_duration_type Used for the offset in the day calculations
+ * @param dst_traits A set of traits that define the rules of dst
+ * calculation. The dst_trait must include the following:
+ * start_rule_functor - Rule to calculate the starting date of a
+ * dst transition (eg: last_kday_of_month).
+ * start_day - static function that returns month of dst start for
+ * start_rule_functor
+ * start_month -static function that returns day or day of week for
+ * dst start of dst
+ * end_rule_functor - Rule to calculate the end of dst day.
+ * end_day - static fucntion that returns end day for end_rule_functor
+ * end_month - static function that returns end month for end_rule_functor
+ * dst_start_offset_minutes - number of minutes from start of day to transition to dst -- 120 (or 2:00 am) is typical for the U.S. and E.U.
+ * dst_start_offset_minutes - number of minutes from start of day to transition off of dst -- 180 (or 3:00 am) is typical for E.U.
+ * dst_length_minutes - number of minutes that dst shifts clock
+ */
+ template<class date_type,
+ class time_duration_type,
+ class dst_traits>
+ class dst_calc_engine
+ {
+ public:
+ typedef typename date_type::year_type year_type;
+ typedef typename date_type::calendar_type calendar_type;
+ typedef dst_calculator<date_type, time_duration_type> dstcalc;
+
+ //! Calculates if the given local time is dst or not
+ /*! Determines if the time is really in DST or not. Also checks for
+ * invalid and ambiguous.
+ * @retval The time is either ambiguous, invalid, in dst, or not in dst
+ */
+ static time_is_dst_result local_is_dst(const date_type& d,
+ const time_duration_type& td)
+ {
+
+ year_type y = d.year();
+ date_type dst_start = local_dst_start_day(y);
+ date_type dst_end = local_dst_end_day(y);
+ return dstcalc::local_is_dst(d,td,
+ dst_start,
+ dst_traits::dst_start_offset_minutes(),
+ dst_end,
+ dst_traits::dst_end_offset_minutes(),
+ dst_traits::dst_shift_length_minutes());
+
+ }
+
+ static bool is_dst_boundary_day(date_type d)
+ {
+ year_type y = d.year();
+ return ((d == local_dst_start_day(y)) ||
+ (d == local_dst_end_day(y)));
+ }
+
+ //! The time of day for the dst transition (eg: typically 01:00:00 or 02:00:00)
+ static time_duration_type dst_offset()
+ {
+ return time_duration_type(0,dst_traits::dst_shift_length_minutes(),0);
+ }
+
+ static date_type local_dst_start_day(year_type year)
+ {
+ return dst_traits::local_dst_start_day(year);
+ }
+
+ static date_type local_dst_end_day(year_type year)
+ {
+ return dst_traits::local_dst_end_day(year);
+ }
+
+
+ };
+
+ //! Depricated: Class to calculate dst boundaries for US time zones
+ /* Use dst_calc_engine instead.
+ * In 2007 US/Canada DST rules changed
+ * (http://en.wikipedia.org/wiki/Energy_Policy_Act_of_2005#Change_to_daylight_saving_time).
+ */
+ template<class date_type_,
+ class time_duration_type_,
+ unsigned int dst_start_offset_minutes=120, //from start of day
+ short dst_length_minutes=60> //1 hour == 60 min in US
+ class us_dst_rules
+ {
+ public:
+ typedef time_duration_type_ time_duration_type;
+ typedef date_type_ date_type;
+ typedef typename date_type::year_type year_type;
+ typedef typename date_type::calendar_type calendar_type;
+ typedef date_time::last_kday_of_month<date_type> lkday;
+ typedef date_time::first_kday_of_month<date_type> fkday;
+ typedef date_time::nth_kday_of_month<date_type> nkday;
+ typedef dst_calculator<date_type, time_duration_type> dstcalc;
+
+ //! Calculates if the given local time is dst or not
+ /*! Determines if the time is really in DST or not. Also checks for
+ * invalid and ambiguous.
+ * @retval The time is either ambiguous, invalid, in dst, or not in dst
+ */
+ static time_is_dst_result local_is_dst(const date_type& d,
+ const time_duration_type& td)
+ {
+
+ year_type y = d.year();
+ date_type dst_start = local_dst_start_day(y);
+ date_type dst_end = local_dst_end_day(y);
+ return dstcalc::local_is_dst(d,td,
+ dst_start,dst_start_offset_minutes,
+ dst_end, dst_start_offset_minutes,
+ dst_length_minutes);
+
+ }
+
+
+ static bool is_dst_boundary_day(date_type d)
+ {
+ year_type y = d.year();
+ return ((d == local_dst_start_day(y)) ||
+ (d == local_dst_end_day(y)));
+ }
+
+ static date_type local_dst_start_day(year_type year)
+ {
+ if (year >= year_type(2007)) {
+ //second sunday in march
+ nkday ssim(nkday::second, Sunday, gregorian::Mar);
+ return ssim.get_date(year);
+ } else {
+ //first sunday in april
+ fkday fsia(Sunday, gregorian::Apr);
+ return fsia.get_date(year);
+ }
+ }
+
+ static date_type local_dst_end_day(year_type year)
+ {
+ if (year >= year_type(2007)) {
+ //first sunday in november
+ fkday fsin(Sunday, gregorian::Nov);
+ return fsin.get_date(year);
+ } else {
+ //last sunday in october
+ lkday lsio(Sunday, gregorian::Oct);
+ return lsio.get_date(year);
+ }
+ }
+
+ static time_duration_type dst_offset()
+ {
+ return time_duration_type(0,dst_length_minutes,0);
+ }
+
+ private:
+
+
+ };
+
+ //! Used for local time adjustments in places that don't use dst
+ template<class date_type_, class time_duration_type_>
+ class null_dst_rules
+ {
+ public:
+ typedef time_duration_type_ time_duration_type;
+ typedef date_type_ date_type;
+
+
+ //! Calculates if the given local time is dst or not
+ /*! @retval Always is_not_in_dst since this is for zones without dst
+ */
+ static time_is_dst_result local_is_dst(const date_type&,
+ const time_duration_type&)
+ {
+ return is_not_in_dst;
+ }
+
+ //! Calculates if the given utc time is in dst
+ static time_is_dst_result utc_is_dst(const date_type&,
+ const time_duration_type&)
+ {
+ return is_not_in_dst;
+ }
+
+ static bool is_dst_boundary_day(date_type d)
+ {
+ return false;
+ }
+
+ static time_duration_type dst_offset()
+ {
+ return time_duration_type(0,0,0);
+ }
+
+ };
+
+
+ } } //namespace date_time
+
+
+
+#endif