views/detail/random_access_view.hpp

0001 // Boost.Geometry
0002
0003 // Copyright (c) 2022-2023, Oracle and/or its affiliates.
0004 // Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
0005 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0006
0007 // Licensed under the Boost Software License version 1.0.
0008 // http://www.boost.org/users/license.html
0009
0010 #ifndef BOOST_GEOMETRY_VIEWS_DETAIL_RANDOM_ACCESS_VIEW_HPP
0011 #define BOOST_GEOMETRY_VIEWS_DETAIL_RANDOM_ACCESS_VIEW_HPP
0012
0013 #include <vector>
0014
0015 #include <boost/range/begin.hpp>
0016 #include <boost/range/end.hpp>
0017 #include <boost/range/iterator.hpp>
0018 #include <boost/range/size.hpp>
0019
0020 #include <boost/geometry/algorithms/detail/visit.hpp>
0021 #include <boost/geometry/core/geometry_types.hpp>
0022 #include <boost/geometry/core/tag.hpp>
0023 #include <boost/geometry/core/tags.hpp>
0024 #include <boost/geometry/util/sequence.hpp>
0025 #include <boost/geometry/util/type_traits.hpp>
0026
0027 namespace boost { namespace geometry
0028 {
0029
0030 #ifndef DOXYGEN_NO_DETAIL
0031 namespace detail
0032 {
0033
0034
0035 template <typename Range>
0036 struct is_random_access_range
0037     : std::is_convertible
0038         <
0039             typename boost::iterator_traversal
0040                 <
0041                     typename boost::range_iterator<Range>::type
0042                 >::type,
0043             boost::random_access_traversal_tag
0044         >
0045 {};
0046
0047 template <typename Geometry>
0048 struct is_geometry_collection_recursive
0049     : util::bool_constant
0050         <
0051             util::is_geometry_collection
0052                 <
0053                     typename util::sequence_find_if
0054                         <
0055                             typename traits::geometry_types<std::remove_const_t<Geometry>>::type,
0056                             util::is_geometry_collection
0057                         >::type
0058                 >::value
0059         >
0060 {};
0061
0062 template
0063 <
0064     typename GeometryCollection,
0065     bool IsRandomAccess = is_random_access_range<GeometryCollection>::value,
0066     bool IsRecursive = is_geometry_collection_recursive<GeometryCollection>::value
0067 >
0068 class random_access_view
0069     : public std::vector<typename boost::range_iterator<GeometryCollection>::type>
0070 {
0071     // NOTE: An alternative would be to implement iterator holding base iterators
0072     //   to geometry collections of lower levels to process after the current level
0073     //   of bfs traversal is finished.
0074
0075     using base_t = std::vector<typename boost::range_iterator<GeometryCollection>::type>;
0076
0077 public:
0078     random_access_view(GeometryCollection & geometry)
0079     {
0080         this->reserve(boost::size(geometry));
0081         detail::visit_breadth_first_impl<true>::apply([&](auto&&, auto iter)
0082         {
0083             this->push_back(iter);
0084             return true;
0085         }, geometry);
0086     }
0087 };
0088
0089 template <typename GeometryCollection>
0090 class random_access_view<GeometryCollection, true, false>
0091 {
0092 public:
0093     using iterator = typename boost::range_iterator<GeometryCollection>::type;
0094     using const_iterator = typename boost::range_const_iterator<GeometryCollection>::type;
0095
0096     random_access_view(GeometryCollection & geometry)
0097         : m_begin(boost::begin(geometry))
0098         , m_end(boost::end(geometry))
0099     {}
0100
0101     iterator begin() { return m_begin; }
0102     iterator end() { return m_end; }
0103     const_iterator begin() const { return m_begin; }
0104     const_iterator end() const { return m_end; }
0105
0106 private:
0107     iterator m_begin, m_end;
0108 };
0109
0110
0111 template <typename GeometryCollection>
0112 struct random_access_view_iter_visit
0113 {
0114     template <typename Function, typename Iterator>
0115     static void apply(Function && function, Iterator iterator)
0116     {
0117         geometry::traits::iter_visit
0118             <
0119                 std::remove_const_t<GeometryCollection>
0120             >::apply(std::forward<Function>(function), *iterator);
0121     }
0122 };
0123
0124
0125 template <typename ...Ts>
0126 struct remove_geometry_collections_pack
0127 {
0128     using type = util::type_sequence<>;
0129 };
0130
0131 template <typename T, typename ...Ts>
0132 struct remove_geometry_collections_pack<T, Ts...>
0133 {
0134     using next_sequence = typename remove_geometry_collections_pack<Ts...>::type;
0135     using type = std::conditional_t
0136         <
0137             util::is_geometry_collection<T>::value,
0138             next_sequence,
0139             typename util::sequence_merge<util::type_sequence<T>, next_sequence>::type
0140         >;
0141 };
0142
0143 template <typename Types>
0144 struct remove_geometry_collections;
0145
0146 template <typename ...Ts>
0147 struct remove_geometry_collections<util::type_sequence<Ts...>>
0148     : remove_geometry_collections_pack<Ts...>
0149 {};
0150
0151
0152 } // namespace detail
0153 #endif // DOXYGEN_NO_DETAIL
0154
0155
0156 #ifndef DOXYGEN_NO_TRAITS_SPECIALIZATIONS
0157 namespace traits
0158 {
0159
0160 template<typename GeometryCollection, bool IsRandomAccess, bool IsRecursive>
0161 struct tag<geometry::detail::random_access_view<GeometryCollection, IsRandomAccess, IsRecursive>>
0162 {
0163     using type = geometry_collection_tag;
0164 };
0165
0166
0167 template <typename GeometryCollection>
0168 struct iter_visit<geometry::detail::random_access_view<GeometryCollection, false, false>>
0169     : geometry::detail::random_access_view_iter_visit<GeometryCollection>
0170 {};
0171
0172 template <typename GeometryCollection>
0173 struct iter_visit<geometry::detail::random_access_view<GeometryCollection, true, true>>
0174     : geometry::detail::random_access_view_iter_visit<GeometryCollection>
0175 {};
0176
0177 template <typename GeometryCollection>
0178 struct iter_visit<geometry::detail::random_access_view<GeometryCollection, false, true>>
0179     : geometry::detail::random_access_view_iter_visit<GeometryCollection>
0180 {};
0181
0182 template <typename GeometryCollection>
0183 struct iter_visit<geometry::detail::random_access_view<GeometryCollection, true, false>>
0184 {
0185     template <typename Function, typename Iterator>
0186     static void apply(Function && function, Iterator iterator)
0187     {
0188         geometry::traits::iter_visit
0189             <
0190                 std::remove_const_t<GeometryCollection>
0191             >::apply(std::forward<Function>(function), iterator);
0192     }
0193 };
0194
0195
0196 template <typename GeometryCollection, bool IsRandomAccess>
0197 struct geometry_types<geometry::detail::random_access_view<GeometryCollection, IsRandomAccess, false>>
0198     : traits::geometry_types
0199         <
0200             std::remove_const_t<GeometryCollection>
0201         >
0202 {};
0203
0204 template <typename GeometryCollection, bool IsRandomAccess>
0205 struct geometry_types<geometry::detail::random_access_view<GeometryCollection, IsRandomAccess, true>>
0206     : geometry::detail::remove_geometry_collections
0207         <
0208             typename traits::geometry_types
0209                 <
0210                     std::remove_const_t<GeometryCollection>
0211                 >::type
0212         >
0213 {};
0214
0215 } // namespace traits
0216 #endif // DOXYGEN_NO_TRAITS_SPECIALIZATIONS
0217
0218
0219 }} // namespace boost::geometry
0220
0221
0222 #endif // BOOST_GEOMETRY_VIEWS_DETAIL_RANDOM_ACCESS_VIEW_HPP