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.hpp>
  19 #include <boost/iterator/iterator_facade.hpp>
  20 #include <boost/iterator/iterator_categories.hpp>
  21
  22
  23
  24 namespace boost { namespace geometry
  25 {
  26
  27 /*!
  28 \brief Iterator which iterates through a range, but adds first element at end of the range
  29 \tparam Range range on which this class is based on
  30 \ingroup iterators
  31 \note It's const iterator treating the Range as one containing non-mutable elements.
  32         For both "closing_iterator<Range> and "closing_iterator<Range const>
  33         const reference is always returned when dereferenced.
  34 \note This class is normally used from "closeable_view" if Close==true
  35 */
  36 template <typename Range>
  37 struct closing_iterator
  38     : public boost::iterator_facade
  39     <
  40         closing_iterator<Range>,
  41         typename boost::range_value<Range>::type const,
  42         boost::random_access_traversal_tag
  43     >
  44 {
  45     typedef typename boost::range_difference<Range>::type difference_type;
  46
  47     /// Constructor including the range it is based on
  48     explicit inline closing_iterator(Range& range)
  49         : m_range(&range)
  50         , m_iterator(boost::begin(range))
  51         , m_end(boost::end(range))
  52         , m_size(static_cast<difference_type>(boost::size(range)))
  53         , m_index(0)
  54     {}
  55
  56     /// Constructor to indicate the end of a range
  57     explicit inline closing_iterator(Range& range, bool)
  58         : m_range(&range)
  59         , m_iterator(boost::end(range))
  60         , m_end(boost::end(range))
  61         , m_size(static_cast<difference_type>(boost::size(range)))
  62         , m_index((m_size == 0) ? 0 : m_size + 1)
  63     {}
  64
  65     /// Default constructor
  66     explicit inline closing_iterator()
  67         : m_range(NULL)
  68         , m_size(0)
  69         , m_index(0)
  70     {}
  71
  72 private:
  73     friend class boost::iterator_core_access;
  74
  75     inline typename boost::range_value<Range>::type const& dereference() const
  76     {
  77         return *m_iterator;
  78     }
  79
  80     inline difference_type distance_to(closing_iterator<Range> const& other) const
  81     {
  82         return other.m_index - this->m_index;
  83     }
  84
  85     inline bool equal(closing_iterator<Range> const& other) const
  86     {
  87         return this->m_range == other.m_range
  88             && this->m_index == other.m_index;
  89     }
  90
  91     inline void increment()
  92     {
  93         if (++m_index < m_size)
  94         {
  95             ++m_iterator;
  96         }
  97         else
  98         {
  99             update_iterator();
 100         }
 101     }
 102
 103     inline void decrement()
 104     {
 105         if (m_index-- < m_size)
 106         {
 107             --m_iterator;
 108         }
 109         else
 110         {
 111             update_iterator();
 112         }
 113     }
 114
 115     inline void advance(difference_type n)
 116     {
 117         if (m_index < m_size && m_index + n < m_size)
 118         {
 119             m_index += n;
 120             m_iterator += n;
 121         }
 122         else
 123         {
 124             m_index += n;
 125             update_iterator();
 126         }
 127     }
 128
 129     inline void update_iterator()
 130     {
 131         this->m_iterator = m_index <= m_size
 132             ? boost::begin(*m_range) + (m_index % m_size)
 133             : boost::end(*m_range)
 134             ;
 135     }
 136
 137     Range* m_range;
 138     typename boost::range_iterator<Range>::type m_iterator;
 139     typename boost::range_iterator<Range>::type m_end;
 140     difference_type m_size;
 141     difference_type m_index;
 142 };
 143
 144
 145 }} // namespace boost::geometry
 146
 147
 148 #endif // BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP