boost/date_time/date_duration.hpp

   1 #ifndef DATE_TIME_DATE_DURATION__
   2 #define DATE_TIME_DATE_DURATION__
   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  * $Date$
  10  */
  11
  12
  13 #include <boost/operators.hpp>
  14 #include <boost/date_time/special_defs.hpp>
  15
  16 namespace boost {
  17 namespace date_time {
  18
  19
  20   //! Duration type with date level resolution
  21   template<class duration_rep_traits>
  22   class date_duration : private
  23               boost::less_than_comparable1< date_duration< duration_rep_traits >
  24             , boost::equality_comparable1< date_duration< duration_rep_traits >
  25             , boost::addable1< date_duration< duration_rep_traits >
  26             , boost::subtractable1< date_duration< duration_rep_traits >
  27             , boost::dividable2< date_duration< duration_rep_traits >, int
  28             > > > > >
  29   {
  30   public:
  31     typedef typename duration_rep_traits::int_type duration_rep_type;
  32     typedef typename duration_rep_traits::impl_type duration_rep;
  33
  34     //! Construct from a day count
  35     explicit date_duration(duration_rep day_count) : days_(day_count) {};
  36
  37     /*! construct from special_values - only works when
  38      * instantiated with duration_traits_adapted */
  39     date_duration(special_values sv) :
  40             days_(duration_rep::from_special(sv))
  41     {}
  42
  43     // copy constructor required for addable<> & subtractable<>
  44     //! Construct from another date_duration (Copy Constructor)
  45     date_duration(const date_duration<duration_rep_traits>& other) :
  46             days_(other.days_)
  47     {}
  48
  49     //! returns days_ as it's instantiated type - used for streaming
  50     duration_rep get_rep()const
  51     {
  52         return days_;
  53     }
  54     bool is_special()const
  55     {
  56         return days_.is_special();
  57     }
  58     //! returns days as value, not object.
  59     duration_rep_type days() const
  60     {
  61         return duration_rep_traits::as_number(days_);
  62     }
  63     //! Returns the smallest duration -- used by to calculate 'end'
  64     static date_duration unit()
  65     {
  66         return date_duration<duration_rep_traits>(1);
  67     }
  68     //! Equality
  69     bool operator==(const date_duration& rhs) const
  70     {
  71         return days_ == rhs.days_;
  72     }
  73     //! Less
  74     bool operator<(const date_duration& rhs) const
  75     {
  76         return days_ < rhs.days_;
  77     }
  78
  79     /* For shortcut operators (+=, -=, etc) simply using
  80      * "days_ += days_" may not work. If instantiated with
  81      * an int_adapter, shortcut operators are not present,
  82      * so this will not compile */
  83
  84     //! Subtract another duration -- result is signed
  85     date_duration& operator-=(const date_duration& rhs)
  86     {
  87         //days_ -= rhs.days_;
  88         days_ = days_ - rhs.days_;
  89         return *this;
  90     }
  91     //! Add a duration -- result is signed
  92     date_duration& operator+=(const date_duration& rhs)
  93     {
  94         days_ = days_ + rhs.days_;
  95         return *this;
  96     }
  97
  98     //! unary- Allows for dd = -date_duration(2); -> dd == -2
  99     date_duration operator-() const
 100     {
 101         return date_duration<duration_rep_traits>(get_rep() * (-1));
 102     }
 103     //! Division operations on a duration with an integer.
 104     date_duration& operator/=(int divisor)
 105     {
 106         days_ = days_ / divisor;
 107         return *this;
 108     }
 109
 110     //! return sign information
 111     bool is_negative() const
 112     {
 113         return days_ < 0;
 114     }
 115
 116   private:
 117     duration_rep days_;
 118   };
 119
 120
 121   /*! Struct for instantiating date_duration with <b>NO</b> special values
 122    * functionality. Allows for transparent implementation of either
 123    * date_duration<long> or date_duration<int_adapter<long> > */
 124   struct duration_traits_long
 125   {
 126     typedef long int_type;
 127     typedef long impl_type;
 128     static int_type as_number(impl_type i) { return i; };
 129   };
 130
 131   /*! Struct for instantiating date_duration <b>WITH</b> special values
 132    * functionality. Allows for transparent implementation of either
 133    * date_duration<long> or date_duration<int_adapter<long> > */
 134   struct duration_traits_adapted
 135   {
 136     typedef long int_type;
 137     typedef boost::date_time::int_adapter<long> impl_type;
 138     static int_type as_number(impl_type i) { return i.as_number(); };
 139   };
 140
 141
 142 } } //namspace date_time
 143
 144
 145 #endif
 146