ceph/src/boost/boost/geometry/iterators/closing_iterator.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
   4 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
   5 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
   6
   7 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
   8 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
   9
  10 // Use, modification and distribution is subject to the Boost Software License,
  11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  12 // http://www.boost.org/LICENSE_1_0.txt)
  13
  14 #ifndef BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP
  15 #define BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP
  16
  17 #include <boost/range.hpp>
  18 #include <boost/iterator/iterator_facade.hpp>
  19 #include <boost/iterator/iterator_categories.hpp>
  20
  21
  22
  23 namespace boost { namespace geometry
  24 {
  25
  26 /*!
  27 \brief Iterator which iterates through a range, but adds first element at end of the range
  28 \tparam Range range on which this class is based on
  29 \ingroup iterators
  30 \note It's const iterator treating the Range as one containing non-mutable elements.
  31         For both "closing_iterator<Range> and "closing_iterator<Range const>
  32         const reference is always returned when dereferenced.
  33 \note This class is normally used from "closeable_view" if Close==true
  34 */
  35 template <typename Range>
  36 struct closing_iterator
  37     : public boost::iterator_facade
  38     <
  39         closing_iterator<Range>,
  40         typename boost::range_value<Range>::type const,
  41         boost::random_access_traversal_tag
  42     >
  43 {
  44     typedef typename boost::range_difference<Range>::type difference_type;
  45
  46     /// Constructor including the range it is based on
  47     explicit inline closing_iterator(Range& range)
  48         : m_range(&range)
  49         , m_iterator(boost::begin(range))
  50         , m_end(boost::end(range))
  51         , m_size(static_cast<difference_type>(boost::size(range)))
  52         , m_index(0)
  53     {}
  54
  55     /// Constructor to indicate the end of a range
  56     explicit inline closing_iterator(Range& range, bool)
  57         : m_range(&range)
  58         , m_iterator(boost::end(range))
  59         , m_end(boost::end(range))
  60         , m_size(static_cast<difference_type>(boost::size(range)))
  61         , m_index((m_size == 0) ? 0 : m_size + 1)
  62     {}
  63
  64     /// Default constructor
  65     explicit inline closing_iterator()
  66         : m_range(NULL)
  67         , m_size(0)
  68         , m_index(0)
  69     {}
  70
  71 private:
  72     friend class boost::iterator_core_access;
  73
  74     inline typename boost::range_value<Range>::type const& dereference() const
  75     {
  76         return *m_iterator;
  77     }
  78
  79     inline difference_type distance_to(closing_iterator<Range> const& other) const
  80     {
  81         return other.m_index - this->m_index;
  82     }
  83
  84     inline bool equal(closing_iterator<Range> const& other) const
  85     {
  86         return this->m_range == other.m_range
  87             && this->m_index == other.m_index;
  88     }
  89
  90     inline void increment()
  91     {
  92         if (++m_index < m_size)
  93         {
  94             ++m_iterator;
  95         }
  96         else
  97         {
  98             update_iterator();
  99         }
 100     }
 101
 102     inline void decrement()
 103     {
 104         if (m_index-- < m_size)
 105         {
 106             --m_iterator;
 107         }
 108         else
 109         {
 110             update_iterator();
 111         }
 112     }
 113
 114     inline void advance(difference_type n)
 115     {
 116         if (m_index < m_size && m_index + n < m_size)
 117         {
 118             m_index += n;
 119             m_iterator += n;
 120         }
 121         else
 122         {
 123             m_index += n;
 124             update_iterator();
 125         }
 126     }
 127
 128     inline void update_iterator()
 129     {
 130         this->m_iterator = m_index <= m_size
 131             ? boost::begin(*m_range) + (m_index % m_size)
 132             : boost::end(*m_range)
 133             ;
 134     }
 135
 136     Range* m_range;
 137     typename boost::range_iterator<Range>::type m_iterator;
 138     typename boost::range_iterator<Range>::type m_end;
 139     difference_type m_size;
 140     difference_type m_index;
 141 };
 142
 143
 144 }} // namespace boost::geometry
 145
 146
 147 #endif // BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP