comparison DEPENDENCIES/generic/include/boost/date_time/period.hpp @ 16:2665513ce2d3

Add boost headers

+#ifndef DATE_TIME_PERIOD_HPP___
+#define DATE_TIME_PERIOD_HPP___
+
+/* Copyright (c) 2002,2003 CrystalClear Software, Inc.
+ * Use, modification and distribution is subject to the 
+ * Boost Software License, Version 1.0. (See accompanying
+ * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+ * Author: Jeff Garland, Bart Garst 
+ * $Date: 2008-02-27 12:00:24 -0800 (Wed, 27 Feb 2008) $
+ */
+
+/*! \file period.hpp
+  This file contain the implementation of the period abstraction. This is
+  basically the same idea as a range.  Although this class is intended for
+  use in the time library, it is pretty close to general enough for other
+  numeric uses.
+
+*/
+
+#include "boost/operators.hpp"
+
+
+namespace boost {
+namespace date_time {
+  //!Provides generalized period type useful in date-time systems
+  /*!This template uses a class to represent a time point within the period
+    and another class to represent a duration.  As a result, this class is
+    not appropriate for use when the number and duration representation 
+    are the same (eg: in the regular number domain).
+    
+    A period can be specified by providing either the begining point and 
+    a duration or the begining point and the end point( end is NOT part 
+    of the period but 1 unit past it. A period will be "invalid" if either
+    end_point <= begin_point or the given duration is <= 0. Any valid period 
+    will return false for is_null().
+    
+    Zero length periods are also considered invalid. Zero length periods are
+    periods where the begining and end points are the same, or, the given 
+    duration is zero. For a zero length period, the last point will be one 
+    unit less than the begining point.
+
+    In the case that the begin and last are the same, the period has a 
+    length of one unit.
+    
+    The best way to handle periods is usually to provide a begining point and
+    a duration.  So, day1 + 7 days is a week period which includes all of the
+    first day and 6 more days (eg: Sun to Sat).
+
+   */
+  template<class point_rep, class duration_rep>
+  class period : private
+      boost::less_than_comparable<period<point_rep, duration_rep> 
+    , boost::equality_comparable< period<point_rep, duration_rep> 
+    > >
+  {
+  public:
+    typedef point_rep point_type;
+    typedef duration_rep duration_type;
+
+    period(point_rep first_point, point_rep end_point);
+    period(point_rep first_point, duration_rep len);
+    point_rep begin() const;
+    point_rep end() const;
+    point_rep last() const;
+    duration_rep length() const;
+    bool is_null() const;
+    bool operator==(const period& rhs) const;
+    bool operator<(const period& rhs) const;
+    void shift(const duration_rep& d);
+    void expand(const duration_rep& d);
+    bool contains(const point_rep& point) const;
+    bool contains(const period& other) const;
+    bool intersects(const period& other) const;
+    bool is_adjacent(const period& other) const;
+    bool is_before(const point_rep& point) const;
+    bool is_after(const point_rep& point) const;
+    period intersection(const period& other) const;
+    period merge(const period& other) const;
+    period span(const period& other) const;
+  private:
+    point_rep begin_;
+    point_rep last_;
+  };
+
+  //! create a period from begin to last eg: [begin,end)
+  /*! If end <= begin then the period will be invalid
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  period<point_rep,duration_rep>::period(point_rep first_point, 
+                                         point_rep end_point) : 
+    begin_(first_point), 
+    last_(end_point - duration_rep::unit())
+  {}
+
+  //! create a period as [begin, begin+len)
+  /*! If len is <= 0 then the period will be invalid
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  period<point_rep,duration_rep>::period(point_rep first_point, duration_rep len) :
+    begin_(first_point), 
+    last_(first_point + len-duration_rep::unit())
+  { }
+
+
+  //! Return the first element in the period
+  template<class point_rep, class duration_rep>
+  inline
+  point_rep period<point_rep,duration_rep>::begin() const 
+  {
+    return begin_;
+  }
+
+  //! Return one past the last element 
+  template<class point_rep, class duration_rep>
+  inline
+  point_rep period<point_rep,duration_rep>::end() const 
+  {
+    return last_ + duration_rep::unit();
+  }
+
+  //! Return the last item in the period
+  template<class point_rep, class duration_rep>
+  inline
+  point_rep period<point_rep,duration_rep>::last() const 
+  {
+    return last_;
+  }
+
+  //! True if period is ill formed (length is zero or less)
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::is_null() const 
+  {
+    return end() <= begin_;
+  }
+
+  //! Return the length of the period
+  template<class point_rep, class duration_rep>
+  inline
+  duration_rep period<point_rep,duration_rep>::length() const
+  {
+    if(last_ < begin_){ // invalid period
+      return last_+duration_rep::unit() - begin_;
+    }
+    else{
+      return end() - begin_; // normal case
+    }
+  }
+
+  //! Equality operator
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::operator==(const period& rhs) const 
+  {
+    return  ((begin_ == rhs.begin_) && 
+             (last_ == rhs.last_));
+  }
+
+  //! Strict as defined by rhs.last <= lhs.last
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::operator<(const period& rhs) const 
+  {
+    return (last_ < rhs.begin_);
+  } 
+
+
+  //! Shift the start and end by the specified amount
+  template<class point_rep, class duration_rep>
+  inline
+  void period<point_rep,duration_rep>::shift(const duration_rep& d)
+  {
+    begin_ = begin_ + d;
+    last_  = last_  + d;
+  }
+
+  /** Expands the size of the period by the duration on both ends.
+   *
+   *So before expand 
+   *@code
+   *
+   *         [-------]
+   * ^   ^   ^   ^   ^   ^  ^
+   * 1   2   3   4   5   6  7
+   * 
+   *@endcode
+   * After expand(2)
+   *@code
+   *
+   * [----------------------]
+   * ^   ^   ^   ^   ^   ^  ^
+   * 1   2   3   4   5   6  7
+   * 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  void period<point_rep,duration_rep>::expand(const duration_rep& d)
+  {
+    begin_ = begin_ - d;
+    last_  = last_  + d;
+  }
+
+  //! True if the point is inside the period, zero length periods contain no points
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::contains(const point_rep& point) const 
+  {
+    return ((point >= begin_) &&
+            (point <= last_));
+  }
+
+
+  //! True if this period fully contains (or equals) the other period
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::contains(const period<point_rep,duration_rep>& other) const
+  {
+    return ((begin_ <= other.begin_) && (last_ >= other.last_));
+  }
+
+
+  //! True if periods are next to each other without a gap.
+  /* In the example below, p1 and p2 are adjacent, but p3 is not adjacent
+   * with either of p1 or p2.
+   *@code
+   *   [-p1-)
+   *        [-p2-)
+   *          [-p3-) 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  bool 
+  period<point_rep,duration_rep>::is_adjacent(const period<point_rep,duration_rep>& other) const 
+  {
+    return (other.begin() == end() ||
+            begin_ == other.end());
+  }
+
+
+  //! True if all of the period is prior or t < start
+  /* In the example below only point 1 would evaluate to true.
+   *@code
+   *     [---------])
+   * ^   ^    ^     ^   ^
+   * 1   2    3     4   5
+   * 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  bool 
+  period<point_rep,duration_rep>::is_after(const point_rep& t) const 
+  { 
+    if (is_null()) 
+    {
+      return false; //null period isn't after
+    }
+    
+    return t < begin_;
+  }
+
+  //! True if all of the period is prior to the passed point or end <= t
+  /* In the example below points 4 and 5 return true.
+   *@code
+   *     [---------])
+   * ^   ^    ^     ^   ^
+   * 1   2    3     4   5
+   * 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  bool 
+  period<point_rep,duration_rep>::is_before(const point_rep& t) const 
+  { 
+    if (is_null()) 
+    {
+      return false;  //null period isn't before anything
+    }
+    
+    return last_ < t;
+  }
+
+
+  //! True if the periods overlap in any way
+  /* In the example below p1 intersects with p2, p4, and p6.
+   *@code
+   *       [---p1---)
+   *             [---p2---)
+   *                [---p3---) 
+   *  [---p4---) 
+   * [-p5-) 
+   *         [-p6-) 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  bool period<point_rep,duration_rep>::intersects(const period<point_rep,duration_rep>& other) const 
+  { 
+    return ( contains(other.begin_) ||
+             other.contains(begin_) ||
+             ((other.begin_ < begin_) && (other.last_ >= begin_)));
+  }
+
+  //! Returns the period of intersection or invalid range no intersection
+  template<class point_rep, class duration_rep>
+  inline
+  period<point_rep,duration_rep>
+  period<point_rep,duration_rep>::intersection(const period<point_rep,duration_rep>& other) const 
+  {
+    if (begin_ > other.begin_) {
+      if (last_ <= other.last_) { //case2
+        return *this;  
+      }
+      //case 1
+      return period<point_rep,duration_rep>(begin_, other.end());
+    }
+    else {
+      if (last_ <= other.last_) { //case3
+        return period<point_rep,duration_rep>(other.begin_, this->end());
+      }
+      //case4
+      return other;
+    }
+    //unreachable
+  }
+
+  //! Returns the union of intersecting periods -- or null period
+  /*! 
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  period<point_rep,duration_rep>
+  period<point_rep,duration_rep>::merge(const period<point_rep,duration_rep>& other) const 
+  {
+    if (this->intersects(other)) {      
+      if (begin_ < other.begin_) {
+        return period<point_rep,duration_rep>(begin_, last_ > other.last_ ? this->end() : other.end());
+      }
+      
+      return period<point_rep,duration_rep>(other.begin_, last_ > other.last_ ? this->end() : other.end());
+      
+    }
+    return period<point_rep,duration_rep>(begin_,begin_); // no intersect return null
+  }
+
+  //! Combine two periods with earliest start and latest end.
+  /*! Combines two periods and any gap between them such that 
+   *  start = min(p1.start, p2.start)
+   *  end   = max(p1.end  , p2.end)
+   *@code
+   *        [---p1---)
+   *                       [---p2---)
+   * result:
+   *        [-----------p3----------) 
+   *@endcode
+   */
+  template<class point_rep, class duration_rep>
+  inline
+  period<point_rep,duration_rep>
+  period<point_rep,duration_rep>::span(const period<point_rep,duration_rep>& other) const 
+  {
+    point_rep start((begin_ < other.begin_) ? begin() : other.begin());
+    point_rep newend((last_  < other.last_)  ? other.end() : this->end());
+    return period<point_rep,duration_rep>(start, newend);
+  }
+
+
+} } //namespace date_time
+
+
+
+#endif