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