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 typename boost::range_reference<Range const>::type, 43 typename boost::range_difference<Range>::type 44 > 45 { 46 private: 47 typedef boost::iterator_facade 48 < 49 closing_iterator<Range>, 50 typename boost::range_value<Range>::type const, 51 boost::random_access_traversal_tag, 52 typename boost::range_reference<Range const>::type, 53 typename boost::range_difference<Range>::type 54 > base_type; 55 56 public: 57 typedef typename base_type::reference reference; 58 typedef typename base_type::difference_type difference_type; 59 60 /// Constructor including the range it is based on closing_iteratorboost::geometry::closing_iterator61 explicit inline closing_iterator(Range& range) 62 : m_range(&range) 63 , m_iterator(boost::begin(range)) 64 , m_end(boost::end(range)) 65 , m_size(static_cast<difference_type>(boost::size(range))) 66 , m_index(0) 67 {} 68 69 /// Constructor to indicate the end of a range closing_iteratorboost::geometry::closing_iterator70 explicit inline closing_iterator(Range& range, bool) 71 : m_range(&range) 72 , m_iterator(boost::end(range)) 73 , m_end(boost::end(range)) 74 , m_size(static_cast<difference_type>(boost::size(range))) 75 , m_index((m_size == 0) ? 0 : m_size + 1) 76 {} 77 78 /// Default constructor closing_iteratorboost::geometry::closing_iterator79 explicit inline closing_iterator() 80 : m_range(NULL) 81 , m_size(0) 82 , m_index(0) 83 {} 84 85 private: 86 friend class boost::iterator_core_access; 87 dereferenceboost::geometry::closing_iterator88 inline reference dereference() const 89 { 90 return *m_iterator; 91 } 92 distance_toboost::geometry::closing_iterator93 inline difference_type distance_to(closing_iterator<Range> const& other) const 94 { 95 return other.m_index - this->m_index; 96 } 97 equalboost::geometry::closing_iterator98 inline bool equal(closing_iterator<Range> const& other) const 99 { 100 return this->m_range == other.m_range 101 && this->m_index == other.m_index; 102 } 103 incrementboost::geometry::closing_iterator104 inline void increment() 105 { 106 if (++m_index < m_size) 107 { 108 ++m_iterator; 109 } 110 else 111 { 112 update_iterator(); 113 } 114 } 115 decrementboost::geometry::closing_iterator116 inline void decrement() 117 { 118 if (m_index-- < m_size) 119 { 120 --m_iterator; 121 } 122 else 123 { 124 update_iterator(); 125 } 126 } 127 advanceboost::geometry::closing_iterator128 inline void advance(difference_type n) 129 { 130 if (m_index < m_size && m_index + n < m_size) 131 { 132 m_index += n; 133 m_iterator += n; 134 } 135 else 136 { 137 m_index += n; 138 update_iterator(); 139 } 140 } 141 update_iteratorboost::geometry::closing_iterator142 inline void update_iterator() 143 { 144 this->m_iterator = m_index <= m_size 145 ? boost::begin(*m_range) + (m_index % m_size) 146 : boost::end(*m_range) 147 ; 148 } 149 150 Range* m_range; 151 typename boost::range_iterator<Range>::type m_iterator; 152 typename boost::range_iterator<Range>::type m_end; 153 difference_type m_size; 154 difference_type m_index; 155 }; 156 157 158 }} // namespace boost::geometry 159 160 161 #endif // BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP 162