[3408] | 1 | #ifndef DATE_TIME_DATE_HPP___ |
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| 2 | #define DATE_TIME_DATE_HPP___ |
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| 3 | |
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| 4 | /* Copyright (c) 2002,2003 CrystalClear Software, Inc. |
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| 5 | * Use, modification and distribution is subject to the |
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| 6 | * Boost Software License, Version 1.0. (See accompanying |
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| 7 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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| 8 | * Author: Jeff Garland, Bart Garst |
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| 9 | * $Date: 2010-01-10 14:17:23 -0500 (Sun, 10 Jan 2010) $ |
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| 10 | */ |
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| 11 | |
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| 12 | #include <boost/operators.hpp> |
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| 13 | #include <boost/date_time/year_month_day.hpp> |
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| 14 | #include <boost/date_time/special_defs.hpp> |
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| 15 | |
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| 16 | namespace boost { |
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| 17 | namespace date_time { |
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| 18 | |
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| 19 | //!Representation of timepoint at the one day level resolution. |
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| 20 | /*! |
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| 21 | The date template represents an interface shell for a date class |
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| 22 | that is based on a year-month-day system such as the gregorian |
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| 23 | or iso systems. It provides basic operations to enable calculation |
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| 24 | and comparisons. |
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| 25 | |
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| 26 | <b>Theory</b> |
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| 27 | |
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| 28 | This date representation fundamentally departs from the C tm struct |
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| 29 | approach. The goal for this type is to provide efficient date |
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| 30 | operations (add, subtract) and storage (minimize space to represent) |
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| 31 | in a concrete class. Thus, the date uses a count internally to |
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| 32 | represent a particular date. The calendar parameter defines |
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| 33 | the policies for converting the the year-month-day and internal |
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| 34 | counted form here. Applications that need to perform heavy |
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| 35 | formatting of the same date repeatedly will perform better |
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| 36 | by using the year-month-day representation. |
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| 37 | |
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| 38 | Internally the date uses a day number to represent the date. |
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| 39 | This is a monotonic time representation. This representation |
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| 40 | allows for fast comparison as well as simplifying |
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| 41 | the creation of writing numeric operations. Essentially, the |
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| 42 | internal day number is like adjusted julian day. The adjustment |
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| 43 | is determined by the Epoch date which is represented as day 1 of |
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| 44 | the calendar. Day 0 is reserved for negative infinity so that |
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| 45 | any actual date is automatically greater than negative infinity. |
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| 46 | When a date is constructed from a date or formatted for output, |
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| 47 | the appropriate conversions are applied to create the year, month, |
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| 48 | day representations. |
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| 49 | */ |
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| 50 | |
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| 51 | |
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| 52 | template<class T, class calendar, class duration_type_> |
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| 53 | class date : private |
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| 54 | boost::less_than_comparable<T |
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| 55 | , boost::equality_comparable<T |
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| 56 | > > |
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| 57 | { |
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| 58 | public: |
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| 59 | typedef T date_type; |
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| 60 | typedef calendar calendar_type; |
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| 61 | typedef typename calendar::date_traits_type traits_type; |
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| 62 | typedef duration_type_ duration_type; |
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| 63 | typedef typename calendar::year_type year_type; |
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| 64 | typedef typename calendar::month_type month_type; |
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| 65 | typedef typename calendar::day_type day_type; |
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| 66 | typedef typename calendar::ymd_type ymd_type; |
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| 67 | typedef typename calendar::date_rep_type date_rep_type; |
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| 68 | typedef typename calendar::date_int_type date_int_type; |
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| 69 | typedef typename calendar::day_of_week_type day_of_week_type; |
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| 70 | date(year_type y, month_type m, day_type d) |
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| 71 | : days_(calendar::day_number(ymd_type(y, m, d))) |
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| 72 | {} |
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| 73 | date(const ymd_type& ymd) |
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| 74 | : days_(calendar::day_number(ymd)) |
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| 75 | {} |
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| 76 | //let the compiler write copy, assignment, and destructor |
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| 77 | year_type year() const |
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| 78 | { |
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| 79 | ymd_type ymd = calendar::from_day_number(days_); |
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| 80 | return ymd.year; |
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| 81 | } |
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| 82 | month_type month() const |
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| 83 | { |
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| 84 | ymd_type ymd = calendar::from_day_number(days_); |
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| 85 | return ymd.month; |
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| 86 | } |
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| 87 | day_type day() const |
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| 88 | { |
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| 89 | ymd_type ymd = calendar::from_day_number(days_); |
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| 90 | return ymd.day; |
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| 91 | } |
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| 92 | day_of_week_type day_of_week() const |
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| 93 | { |
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| 94 | ymd_type ymd = calendar::from_day_number(days_); |
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| 95 | return calendar::day_of_week(ymd); |
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| 96 | } |
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| 97 | ymd_type year_month_day() const |
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| 98 | { |
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| 99 | return calendar::from_day_number(days_); |
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| 100 | } |
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| 101 | bool operator<(const date_type& rhs) const |
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| 102 | { |
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| 103 | return days_ < rhs.days_; |
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| 104 | } |
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| 105 | bool operator==(const date_type& rhs) const |
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| 106 | { |
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| 107 | return days_ == rhs.days_; |
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| 108 | } |
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| 109 | //! check to see if date is a special value |
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| 110 | bool is_special()const |
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| 111 | { |
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| 112 | return(is_not_a_date() || is_infinity()); |
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| 113 | } |
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| 114 | //! check to see if date is not a value |
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| 115 | bool is_not_a_date() const |
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| 116 | { |
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| 117 | return traits_type::is_not_a_number(days_); |
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| 118 | } |
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| 119 | //! check to see if date is one of the infinity values |
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| 120 | bool is_infinity() const |
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| 121 | { |
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| 122 | return traits_type::is_inf(days_); |
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| 123 | } |
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| 124 | //! check to see if date is greater than all possible dates |
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| 125 | bool is_pos_infinity() const |
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| 126 | { |
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| 127 | return traits_type::is_pos_inf(days_); |
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| 128 | } |
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| 129 | //! check to see if date is greater than all possible dates |
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| 130 | bool is_neg_infinity() const |
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| 131 | { |
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| 132 | return traits_type::is_neg_inf(days_); |
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| 133 | } |
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| 134 | //! return as a special value or a not_special if a normal date |
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| 135 | special_values as_special() const |
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| 136 | { |
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| 137 | return traits_type::to_special(days_); |
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| 138 | } |
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| 139 | duration_type operator-(const date_type& d) const |
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| 140 | { |
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| 141 | if (!this->is_special() && !d.is_special()) |
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| 142 | { |
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| 143 | // The duration underlying type may be wider than the date underlying type. |
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| 144 | // Thus we calculate the difference in terms of two durations from some common fixed base date. |
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| 145 | typedef typename duration_type::duration_rep_type duration_rep_type; |
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| 146 | return duration_type(static_cast< duration_rep_type >(days_) - static_cast< duration_rep_type >(d.days_)); |
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| 147 | } |
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| 148 | else |
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| 149 | { |
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| 150 | // In this case the difference will be a special value, too |
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| 151 | date_rep_type val = date_rep_type(days_) - date_rep_type(d.days_); |
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| 152 | return duration_type(val.as_special()); |
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| 153 | } |
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| 154 | } |
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| 155 | |
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| 156 | date_type operator-(const duration_type& dd) const |
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| 157 | { |
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| 158 | if(dd.is_special()) |
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| 159 | { |
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| 160 | return date_type(date_rep_type(days_) - dd.get_rep()); |
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| 161 | } |
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| 162 | return date_type(date_rep_type(days_) - dd.days()); |
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| 163 | } |
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| 164 | date_type operator-=(const duration_type& dd) |
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| 165 | { |
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| 166 | *this = *this - dd; |
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| 167 | return date_type(days_); |
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| 168 | } |
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| 169 | date_rep_type day_count() const |
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| 170 | { |
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| 171 | return days_; |
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| 172 | } |
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| 173 | //allow internal access from operators |
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| 174 | date_type operator+(const duration_type& dd) const |
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| 175 | { |
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| 176 | if(dd.is_special()) |
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| 177 | { |
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| 178 | return date_type(date_rep_type(days_) + dd.get_rep()); |
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| 179 | } |
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| 180 | return date_type(date_rep_type(days_) + dd.days()); |
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| 181 | } |
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| 182 | date_type operator+=(const duration_type& dd) |
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| 183 | { |
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| 184 | *this = *this + dd; |
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| 185 | return date_type(days_); |
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| 186 | } |
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| 187 | |
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| 188 | //see reference |
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| 189 | protected: |
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| 190 | /*! This is a private constructor which allows for the creation of new |
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| 191 | dates. It is not exposed to users since that would require class |
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| 192 | users to understand the inner workings of the date class. |
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| 193 | */ |
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| 194 | explicit date(date_int_type days) : days_(days) {}; |
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| 195 | explicit date(date_rep_type days) : days_(days.as_number()) {}; |
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| 196 | date_int_type days_; |
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| 197 | |
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| 198 | }; |
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| 199 | |
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| 200 | |
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| 201 | |
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| 202 | |
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| 203 | } } // namespace date_time |
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| 204 | |
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| 205 | |
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| 206 | |
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| 207 | |
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| 208 | #endif |
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