103 lines
3.2 KiB
C++
103 lines
3.2 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
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// This file was modified by Oracle on 2020-2021.
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// Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_VIEWS_SEGMENT_VIEW_HPP
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#define BOOST_GEOMETRY_VIEWS_SEGMENT_VIEW_HPP
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#include <array>
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#include <boost/geometry/algorithms/detail/assign_indexed_point.hpp>
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#include <boost/geometry/core/point_type.hpp>
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#include <boost/geometry/core/tag.hpp>
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namespace boost { namespace geometry
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{
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// NOTE: This is equivalent to the previous implementation with detail::points_view.
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// Technically this should not be called a view because it owns the elements.
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// It's also not a borrowed_range because of dangling iterators after the
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// destruction.
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// It's a container or more specifically a linestring of some sort, e.g. static_linestring.
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// NOTE: It would be possible to implement a borrowed_range or a view.
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// The iterators would have to store copies of points.
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// Another possibility is to store the original Segment or reference/pointer
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// to Segment and index. But then the reference would be the value type
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// so technically they would be InputIterators not RandomAccessIterators.
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/*!
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\brief Makes a segment behave like a linestring or a range
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\details Adapts a segment to the Boost.Range concept, enabling the user to
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iterate the two segment points. The segment_view is registered as a LineString Concept
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\tparam Segment \tparam_geometry{Segment}
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\ingroup views
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\qbk{before.synopsis,
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[heading Model of]
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[link geometry.reference.concepts.concept_linestring LineString Concept]
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}
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\qbk{[include reference/views/segment_view.qbk]}
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*/
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template <typename Segment>
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struct segment_view
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{
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using array_t = std::array<typename geometry::point_type<Segment>::type, 2>;
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using iterator = typename array_t::const_iterator;
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using const_iterator = typename array_t::const_iterator;
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/// Constructor accepting the segment to adapt
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explicit segment_view(Segment const& segment)
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{
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geometry::detail::assign_point_from_index<0>(segment, m_array[0]);
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geometry::detail::assign_point_from_index<1>(segment, m_array[1]);
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}
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const_iterator begin() const noexcept { return m_array.begin(); }
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const_iterator end() const noexcept { return m_array.end(); }
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private:
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array_t m_array;
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};
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#ifndef DOXYGEN_NO_TRAITS_SPECIALIZATIONS
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// All segment ranges can be handled as linestrings
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namespace traits
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{
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template<typename Segment>
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struct tag<segment_view<Segment> >
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{
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typedef linestring_tag type;
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};
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}
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#endif // DOXYGEN_NO_TRAITS_SPECIALIZATIONS
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_VIEWS_SEGMENT_VIEW_HPP
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