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219 lines
7.7 KiB
219 lines
7.7 KiB
/* Copyright (c) 2002,2003 CrystalClear Software, Inc. |
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* Use, modification and distribution is subject to the |
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* Boost Software License, Version 1.0. (See accompanying |
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* file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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* Author: Jeff Garland, Bart Garst |
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* $Date: 2011-11-13 01:10:55 -0500 (Sun, 13 Nov 2011) $ |
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*/ |
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#ifndef NO_BOOST_DATE_TIME_INLINE |
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#undef BOOST_DATE_TIME_INLINE |
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#define BOOST_DATE_TIME_INLINE inline |
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#endif |
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namespace boost { |
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namespace date_time { |
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//! Return the day of the week (0==Sunday, 1==Monday, etc) |
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/*! Converts a year-month-day into a day of the week number |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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unsigned short |
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gregorian_calendar_base<ymd_type_,date_int_type_>::day_of_week(const ymd_type& ymd) { |
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unsigned short a = static_cast<unsigned short>((14-ymd.month)/12); |
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unsigned short y = static_cast<unsigned short>(ymd.year - a); |
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unsigned short m = static_cast<unsigned short>(ymd.month + 12*a - 2); |
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unsigned short d = static_cast<unsigned short>((ymd.day + y + (y/4) - (y/100) + (y/400) + (31*m)/12) % 7); |
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//std::cout << year << "-" << month << "-" << day << " is day: " << d << "\n"; |
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return d; |
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} |
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//!Return the iso week number for the date |
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/*!Implements the rules associated with the iso 8601 week number. |
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Basically the rule is that Week 1 of the year is the week that contains |
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January 4th or the week that contains the first Thursday in January. |
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Reference for this algorithm is the Calendar FAQ by Claus Tondering, April 2000. |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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int |
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gregorian_calendar_base<ymd_type_,date_int_type_>::week_number(const ymd_type& ymd) { |
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unsigned long julianbegin = julian_day_number(ymd_type(ymd.year,1,1)); |
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unsigned long juliantoday = julian_day_number(ymd); |
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unsigned long day = (julianbegin + 3) % 7; |
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unsigned long week = (juliantoday + day - julianbegin + 4)/7; |
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if ((week >= 1) && (week <= 52)) { |
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return week; |
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} |
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if (week == 53) { |
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if((day==6) ||(day == 5 && is_leap_year(ymd.year))) { |
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return week; //under these circumstances week == 53. |
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} else { |
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return 1; //monday - wednesday is in week 1 of next year |
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} |
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} |
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//if the week is not in current year recalculate using the previous year as the beginning year |
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else if (week == 0) { |
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julianbegin = julian_day_number(ymd_type(static_cast<unsigned short>(ymd.year-1),1,1)); |
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juliantoday = julian_day_number(ymd); |
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day = (julianbegin + 3) % 7; |
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week = (juliantoday + day - julianbegin + 4)/7; |
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return week; |
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} |
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return week; //not reachable -- well except if day == 5 and is_leap_year != true |
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} |
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//! Convert a ymd_type into a day number |
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/*! The day number is an absolute number of days since the start of count |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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date_int_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::day_number(const ymd_type& ymd) |
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{ |
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unsigned short a = static_cast<unsigned short>((14-ymd.month)/12); |
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unsigned short y = static_cast<unsigned short>(ymd.year + 4800 - a); |
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unsigned short m = static_cast<unsigned short>(ymd.month + 12*a - 3); |
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unsigned long d = ymd.day + ((153*m + 2)/5) + 365*y + (y/4) - (y/100) + (y/400) - 32045; |
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return d; |
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} |
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//! Convert a year-month-day into the julian day number |
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/*! Since this implementation uses julian day internally, this is the same as the day_number. |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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date_int_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::julian_day_number(const ymd_type& ymd) |
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{ |
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return day_number(ymd); |
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} |
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//! Convert year-month-day into a modified julian day number |
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/*! The day number is an absolute number of days. |
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* MJD 0 thus started on 17 Nov 1858(Gregorian) at 00:00:00 UTC |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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date_int_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::modjulian_day_number(const ymd_type& ymd) |
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{ |
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return julian_day_number(ymd)-2400001; //prerounded |
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} |
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//! Change a day number into a year-month-day |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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ymd_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::from_day_number(date_int_type dayNumber) |
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{ |
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date_int_type a = dayNumber + 32044; |
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date_int_type b = (4*a + 3)/146097; |
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date_int_type c = a-((146097*b)/4); |
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date_int_type d = (4*c + 3)/1461; |
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date_int_type e = c - (1461*d)/4; |
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date_int_type m = (5*e + 2)/153; |
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unsigned short day = static_cast<unsigned short>(e - ((153*m + 2)/5) + 1); |
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unsigned short month = static_cast<unsigned short>(m + 3 - 12 * (m/10)); |
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year_type year = static_cast<unsigned short>(100*b + d - 4800 + (m/10)); |
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//std::cout << year << "-" << month << "-" << day << "\n"; |
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return ymd_type(static_cast<unsigned short>(year),month,day); |
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} |
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//! Change a day number into a year-month-day |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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ymd_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::from_julian_day_number(date_int_type dayNumber) |
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{ |
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date_int_type a = dayNumber + 32044; |
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date_int_type b = (4*a+3)/146097; |
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date_int_type c = a - ((146097*b)/4); |
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date_int_type d = (4*c + 3)/1461; |
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date_int_type e = c - ((1461*d)/4); |
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date_int_type m = (5*e + 2)/153; |
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unsigned short day = static_cast<unsigned short>(e - ((153*m + 2)/5) + 1); |
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unsigned short month = static_cast<unsigned short>(m + 3 - 12 * (m/10)); |
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year_type year = static_cast<year_type>(100*b + d - 4800 + (m/10)); |
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//std::cout << year << "-" << month << "-" << day << "\n"; |
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return ymd_type(year,month,day); |
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} |
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//! Change a modified julian day number into a year-month-day |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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ymd_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::from_modjulian_day_number(date_int_type dayNumber) { |
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date_int_type jd = dayNumber + 2400001; //is 2400000.5 prerounded |
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return from_julian_day_number(jd); |
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} |
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//! Determine if the provided year is a leap year |
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/*! |
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*@return true if year is a leap year, false otherwise |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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bool |
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gregorian_calendar_base<ymd_type_,date_int_type_>::is_leap_year(year_type year) |
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{ |
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//divisible by 4, not if divisible by 100, but true if divisible by 400 |
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return (!(year % 4)) && ((year % 100) || (!(year % 400))); |
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} |
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//! Calculate the last day of the month |
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/*! Find the day which is the end of the month given year and month |
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* No error checking is performed. |
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*/ |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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unsigned short |
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gregorian_calendar_base<ymd_type_,date_int_type_>::end_of_month_day(year_type year, |
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month_type month) |
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{ |
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switch (month) { |
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case 2: |
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if (is_leap_year(year)) { |
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return 29; |
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} else { |
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return 28; |
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}; |
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case 4: |
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case 6: |
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case 9: |
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case 11: |
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return 30; |
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default: |
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return 31; |
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}; |
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} |
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//! Provide the ymd_type specification for the calandar start |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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ymd_type_ |
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gregorian_calendar_base<ymd_type_,date_int_type_>::epoch() |
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{ |
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return ymd_type(1400,1,1); |
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} |
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//! Defines length of a week for week calculations |
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template<typename ymd_type_, typename date_int_type_> |
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BOOST_DATE_TIME_INLINE |
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unsigned short |
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gregorian_calendar_base<ymd_type_,date_int_type_>::days_in_week() |
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{ |
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return 7; |
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} |
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} } //namespace gregorian |
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