// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2014-2020, Oracle and/or its affiliates.
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// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Licensed under the Boost Software License version 1.0.
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// http://www.boost.org/users/license.html
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#ifndef BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
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#define BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
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#include <type_traits>
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#include <boost/iterator/iterator_facade.hpp>
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#include <boost/iterator/iterator_categories.hpp>
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#include <boost/range/begin.hpp>
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#include <boost/range/end.hpp>
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#include <boost/range/size.hpp>
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#include <boost/geometry/core/closure.hpp>
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#include <boost/geometry/core/static_assert.hpp>
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#include <boost/geometry/iterators/closing_iterator.hpp>
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namespace boost { namespace geometry
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{
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace segment_iterator
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{
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template <typename Range, closure_selector Closure = closure<Range>::value>
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struct range_iterator_type
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{
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typedef typename boost::range_iterator<Range>::type type;
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};
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template <typename Range>
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struct range_iterator_type<Range, open>
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{
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typedef closing_iterator<Range> type;
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};
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template <typename Range, closure_selector Closure = closure<Range>::value>
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struct range_iterator_begin
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{
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static inline typename range_iterator_type<Range, Closure>::type
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apply(Range& range)
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{
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return boost::begin(range);
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}
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};
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template <typename Range>
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struct range_iterator_begin<Range, open>
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{
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static inline typename range_iterator_type<Range, open>::type
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apply(Range& range)
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{
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return closing_iterator<Range>(range);
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}
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};
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template <typename Range, closure_selector Closure = closure<Range>::value>
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struct range_iterator_end
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{
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static inline typename range_iterator_type<Range, Closure>::type
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apply(Range& range)
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{
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return boost::end(range);
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}
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};
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template <typename Range>
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struct range_iterator_end<Range, open>
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{
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static inline typename range_iterator_type<Range, open>::type
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apply(Range& range)
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{
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return closing_iterator<Range>(range, true);
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}
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};
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template <typename Range, typename Value, typename Reference = Value>
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class range_segment_iterator
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: public boost::iterator_facade
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<
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range_segment_iterator<Range, Value, Reference>,
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Value,
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boost::bidirectional_traversal_tag,
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Reference
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>
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{
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static inline bool has_less_than_two_elements(Range const& r)
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{
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return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u);
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}
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public:
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typedef typename range_iterator_type<Range>::type iterator_type;
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// default constructor
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range_segment_iterator()
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: m_it(), m_has_less_than_two_elements(false)
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{}
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// for begin
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range_segment_iterator(Range& r)
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: m_it(range_iterator_begin<Range>::apply(r))
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, m_has_less_than_two_elements(has_less_than_two_elements(r))
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{}
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// for end
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range_segment_iterator(Range& r, bool)
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: m_it(range_iterator_end<Range>::apply(r))
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, m_has_less_than_two_elements(has_less_than_two_elements(r))
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{
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if (! m_has_less_than_two_elements)
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{
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// the range consists of at least two items
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--m_it;
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}
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}
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template
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<
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typename OtherRange,
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typename OtherValue,
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typename OtherReference
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>
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range_segment_iterator(range_segment_iterator
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<
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OtherRange,
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OtherValue,
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OtherReference
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> const& other)
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: m_it(other.m_it)
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{
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typedef typename range_segment_iterator
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<
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OtherRange, OtherValue, OtherReference
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>::iterator_type other_iterator_type;
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static const bool are_conv
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= std::is_convertible<other_iterator_type, iterator_type>::value;
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BOOST_GEOMETRY_STATIC_ASSERT((are_conv),
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"Other iterator has to be convertible to member iterator.",
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OtherRange);
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}
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private:
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friend class boost::iterator_core_access;
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template <typename Rng, typename V, typename R>
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friend class range_segment_iterator;
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inline Reference dereference() const
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{
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if (m_has_less_than_two_elements)
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{
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return Reference(*m_it, *m_it);
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}
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iterator_type next(m_it);
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++next;
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return Reference(*m_it, *next);
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}
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template
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<
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typename OtherRange,
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typename OtherValue,
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typename OtherReference
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>
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inline bool equal(range_segment_iterator
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<
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OtherRange,
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OtherValue,
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OtherReference
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> const& other) const
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{
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return m_it == other.m_it;
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}
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inline void increment()
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{
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++m_it;
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}
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inline void decrement()
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{
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--m_it;
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}
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private:
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iterator_type m_it;
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bool m_has_less_than_two_elements;
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};
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}} // namespace detail::segment_iterator
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#endif // DOXYGEN_NO_DETAIL
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
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