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/Src/Dependencies/Boost/boost/date_time/date.hpp

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C++ Header | 208 lines | 137 code | 17 blank | 54 comment | 6 complexity | 91ad6586f2009ea0e201312fa188f77b MD5 | raw file
  1#ifndef DATE_TIME_DATE_HPP___
  2#define DATE_TIME_DATE_HPP___
  3
  4/* Copyright (c) 2002,2003 CrystalClear Software, Inc.
  5 * Use, modification and distribution is subject to the
  6 * Boost Software License, Version 1.0. (See accompanying
  7 * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
  8 * Author: Jeff Garland, Bart Garst
  9 * $Date: 2010-01-11 06:17:23 +1100 (Mon, 11 Jan 2010) $
 10 */
 11
 12#include <boost/operators.hpp>
 13#include <boost/date_time/year_month_day.hpp>
 14#include <boost/date_time/special_defs.hpp>
 15
 16namespace boost {
 17namespace date_time {
 18
 19  //!Representation of timepoint at the one day level resolution.
 20  /*!
 21    The date template represents an interface shell for a date class
 22    that is based on a year-month-day system such as the gregorian
 23    or iso systems.  It provides basic operations to enable calculation
 24    and comparisons.
 25
 26    <b>Theory</b>
 27
 28    This date representation fundamentally departs from the C tm struct
 29    approach.  The goal for this type is to provide efficient date
 30    operations (add, subtract) and storage (minimize space to represent)
 31    in a concrete class.  Thus, the date uses a count internally to
 32    represent a particular date.  The calendar parameter defines
 33    the policies for converting the the year-month-day and internal
 34    counted form here.  Applications that need to perform heavy
 35    formatting of the same date repeatedly will perform better
 36    by using the year-month-day representation.
 37
 38    Internally the date uses a day number to represent the date.
 39    This is a monotonic time representation. This representation
 40    allows for fast comparison as well as simplifying
 41    the creation of writing numeric operations.  Essentially, the
 42    internal day number is like adjusted julian day.  The adjustment
 43    is determined by the Epoch date which is represented as day 1 of
 44    the calendar.  Day 0 is reserved for negative infinity so that
 45    any actual date is automatically greater than negative infinity.
 46    When a date is constructed from a date or formatted for output,
 47    the appropriate conversions are applied to create the year, month,
 48    day representations.
 49  */
 50
 51
 52  template<class T, class calendar, class duration_type_>
 53  class date : private
 54       boost::less_than_comparable<T
 55     , boost::equality_comparable<T
 56    > >
 57  {
 58  public:
 59    typedef T date_type;
 60    typedef calendar calendar_type;
 61    typedef typename calendar::date_traits_type traits_type;
 62    typedef duration_type_ duration_type;
 63    typedef typename calendar::year_type year_type;
 64    typedef typename calendar::month_type month_type;
 65    typedef typename calendar::day_type day_type;
 66    typedef typename calendar::ymd_type ymd_type;
 67    typedef typename calendar::date_rep_type date_rep_type;
 68    typedef typename calendar::date_int_type date_int_type;
 69    typedef typename calendar::day_of_week_type day_of_week_type;
 70    date(year_type y, month_type m, day_type d)
 71      : days_(calendar::day_number(ymd_type(y, m, d)))
 72    {}
 73    date(const ymd_type& ymd)
 74      : days_(calendar::day_number(ymd))
 75    {}
 76    //let the compiler write copy, assignment, and destructor
 77    year_type        year() const
 78    {
 79      ymd_type ymd = calendar::from_day_number(days_);
 80      return ymd.year;
 81    }
 82    month_type       month() const
 83    {
 84      ymd_type ymd = calendar::from_day_number(days_);
 85      return ymd.month;
 86    }
 87    day_type         day() const
 88    {
 89      ymd_type ymd = calendar::from_day_number(days_);
 90      return ymd.day;
 91    }
 92    day_of_week_type day_of_week() const
 93    {
 94      ymd_type ymd = calendar::from_day_number(days_);
 95      return calendar::day_of_week(ymd);
 96    }
 97    ymd_type         year_month_day() const
 98    {
 99      return calendar::from_day_number(days_);
100    }
101    bool operator<(const date_type& rhs)  const
102    {
103      return days_ < rhs.days_;
104    }
105    bool operator==(const date_type& rhs) const
106    {
107      return days_ == rhs.days_;
108    }
109    //! check to see if date is a special value
110    bool is_special()const
111    {
112      return(is_not_a_date() || is_infinity());
113    }
114    //! check to see if date is not a value
115    bool is_not_a_date()  const
116    {
117      return traits_type::is_not_a_number(days_);
118    }
119    //! check to see if date is one of the infinity values
120    bool is_infinity()  const
121    {
122      return traits_type::is_inf(days_);
123    }
124    //! check to see if date is greater than all possible dates
125    bool is_pos_infinity()  const
126    {
127      return traits_type::is_pos_inf(days_);
128    }
129    //! check to see if date is greater than all possible dates
130    bool is_neg_infinity()  const
131    {
132      return traits_type::is_neg_inf(days_);
133    }
134    //! return as a special value or a not_special if a normal date
135    special_values as_special()  const
136    {
137      return traits_type::to_special(days_);
138    }
139    duration_type operator-(const date_type& d) const
140    {
141      if (!this->is_special() && !d.is_special())
142      {
143        // The duration underlying type may be wider than the date underlying type.
144        // Thus we calculate the difference in terms of two durations from some common fixed base date.
145        typedef typename duration_type::duration_rep_type duration_rep_type;
146        return duration_type(static_cast< duration_rep_type >(days_) - static_cast< duration_rep_type >(d.days_));
147      }
148      else
149      {
150        // In this case the difference will be a special value, too
151        date_rep_type val = date_rep_type(days_) - date_rep_type(d.days_);
152        return duration_type(val.as_special());
153      }
154    }
155
156    date_type operator-(const duration_type& dd) const
157    {
158      if(dd.is_special())
159      {
160        return date_type(date_rep_type(days_) - dd.get_rep());
161      }
162      return date_type(date_rep_type(days_) - dd.days());
163    }
164    date_type operator-=(const duration_type& dd)
165    {
166      *this = *this - dd;
167      return date_type(days_);
168    }
169    date_rep_type day_count() const
170    {
171      return days_;
172    }
173    //allow internal access from operators
174    date_type operator+(const duration_type& dd) const
175    {
176      if(dd.is_special())
177      {
178        return date_type(date_rep_type(days_) + dd.get_rep());
179      }
180      return date_type(date_rep_type(days_) + dd.days());
181    }
182    date_type operator+=(const duration_type& dd)
183    {
184      *this = *this + dd;
185      return date_type(days_);
186    }
187
188    //see reference
189  protected:
190    /*! This is a private constructor which allows for the creation of new
191      dates.  It is not exposed to users since that would require class
192      users to understand the inner workings of the date class.
193    */
194    explicit date(date_int_type days) : days_(days) {};
195    explicit date(date_rep_type days) : days_(days.as_number()) {};
196    date_int_type days_;
197
198  };
199
200
201
202
203} } // namespace date_time
204
205
206
207
208#endif