algorithms/detail/sub_range.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002
0003 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
0004
0005 // This file was modified by Oracle on 2013-2020.
0006 // Modifications copyright (c) 2013-2020, Oracle and/or its affiliates.
0007
0008 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0009
0010 // Use, modification and distribution is subject to the Boost Software License,
0011 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0012 // http://www.boost.org/LICENSE_1_0.txt)
0013
0014 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_SUB_RANGE_HPP
0015 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_SUB_RANGE_HPP
0016
0017 #include <type_traits>
0018
0019 #include <boost/geometry/algorithms/not_implemented.hpp>
0020
0021 #include <boost/geometry/core/assert.hpp>
0022 #include <boost/geometry/core/exterior_ring.hpp>
0023 #include <boost/geometry/core/interior_rings.hpp>
0024 #include <boost/geometry/core/tag.hpp>
0025 #include <boost/geometry/core/tags.hpp>
0026
0027 #include <boost/geometry/util/range.hpp>
0028 #include <boost/geometry/util/type_traits.hpp>
0029
0030 namespace boost { namespace geometry {
0031
0032 #ifndef DOXYGEN_NO_DETAIL
0033
0034 #ifndef DOXYGEN_NO_DISPATCH
0035 namespace detail_dispatch {
0036
0037 template
0038 <
0039     typename Geometry,
0040     typename Tag = geometry::tag_t<Geometry>,
0041     bool IsMulti = util::is_multi<Geometry>::value
0042 >
0043 struct sub_range : not_implemented<Tag>
0044 {};
0045
0046 template <typename Geometry, typename Tag>
0047 struct sub_range<Geometry, Tag, false>
0048 {
0049     typedef Geometry & return_type;
0050
0051     template <typename Id> static inline
0052     return_type apply(Geometry & geometry, Id const&)
0053     {
0054         return geometry;
0055     }
0056 };
0057
0058 template <typename Geometry>
0059 struct sub_range<Geometry, polygon_tag, false>
0060 {
0061     using return_type = geometry::ring_return_type_t<Geometry>;
0062
0063     template <typename Id> static inline
0064     return_type apply(Geometry & geometry, Id const& id)
0065     {
0066         if ( id.ring_index < 0 )
0067         {
0068             return geometry::exterior_ring(geometry);
0069         }
0070         else
0071         {
0072             using size_type = typename boost::range_size
0073                 <
0074                     typename geometry::interior_type<Geometry>::type
0075                 >::type;
0076             size_type const ri = static_cast<size_type>(id.ring_index);
0077             return range::at(geometry::interior_rings(geometry), ri);
0078         }
0079     }
0080 };
0081
0082 template <typename Geometry, typename Tag>
0083 struct sub_range<Geometry, Tag, true>
0084 {
0085     typedef typename boost::range_value<Geometry>::type value_type;
0086     typedef std::conditional_t
0087         <
0088             std::is_const<Geometry>::value,
0089             typename std::add_const<value_type>::type,
0090             value_type
0091         > sub_type;
0092
0093     typedef detail_dispatch::sub_range<sub_type> sub_sub_range;
0094
0095     // TODO: shouldn't it be return_type?
0096     typedef typename sub_sub_range::return_type return_type;
0097
0098     template <typename Id> static inline
0099     return_type apply(Geometry & geometry, Id const& id)
0100     {
0101         BOOST_GEOMETRY_ASSERT(0 <= id.multi_index);
0102         typedef typename boost::range_size<Geometry>::type size_type;
0103         size_type const mi = static_cast<size_type>(id.multi_index);
0104         return sub_sub_range::apply(range::at(geometry, mi), id);
0105     }
0106 };
0107
0108 } // namespace detail_dispatch
0109 #endif // DOXYGEN_NO_DISPATCH
0110
0111 namespace detail {
0112
0113 template <typename Geometry>
0114 struct sub_range_return_type
0115 {
0116     typedef typename detail_dispatch::sub_range<Geometry>::return_type type;
0117 };
0118
0119 // This function also works for geometry::segment_identifier
0120
0121 template <typename Geometry, typename Id> inline
0122 typename sub_range_return_type<Geometry>::type
0123 sub_range(Geometry & geometry, Id const& id)
0124 {
0125     return detail_dispatch::sub_range<Geometry>::apply(geometry, id);
0126 }
0127
0128 template <typename Geometry, typename Id> inline
0129 typename sub_range_return_type<Geometry const>::type
0130 sub_range(Geometry const& geometry, Id const& id)
0131 {
0132     return detail_dispatch::sub_range<Geometry const>::apply(geometry, id);
0133 }
0134
0135 } // namespace detail
0136 #endif // DOXYGEN_NO_DETAIL
0137
0138 }} // namespace boost::geometry
0139
0140 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_SUB_RANGE_HPP