reverse.hpp 4.5 KB

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  1. // Boost.Geometry (aka GGL, Generic Geometry Library)
  2. // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
  3. // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
  4. // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
  5. // Copyright (c) 2014 Adam Wulkiewicz, Lodz, Poland.
  6. // This file was modified by Oracle on 2020-2021.
  7. // Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
  8. // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  9. // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
  10. // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
  11. // Use, modification and distribution is subject to the Boost Software License,
  12. // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  13. // http://www.boost.org/LICENSE_1_0.txt)
  14. #ifndef BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  15. #define BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  16. #include <algorithm>
  17. #include <boost/range/begin.hpp>
  18. #include <boost/range/end.hpp>
  19. #include <boost/geometry/algorithms/detail/interior_iterator.hpp>
  20. #include <boost/geometry/algorithms/detail/multi_modify.hpp>
  21. #include <boost/geometry/algorithms/detail/visit.hpp>
  22. #include <boost/geometry/core/interior_rings.hpp>
  23. #include <boost/geometry/core/tags.hpp>
  24. #include <boost/geometry/core/visit.hpp>
  25. #include <boost/geometry/geometries/adapted/boost_variant.hpp> // For backward compatibility
  26. #include <boost/geometry/geometries/concepts/check.hpp>
  27. #include <boost/geometry/util/type_traits.hpp>
  28. namespace boost { namespace geometry
  29. {
  30. #ifndef DOXYGEN_NO_DETAIL
  31. namespace detail { namespace reverse
  32. {
  33. struct range_reverse
  34. {
  35. template <typename Range>
  36. static inline void apply(Range& range)
  37. {
  38. std::reverse(boost::begin(range), boost::end(range));
  39. }
  40. };
  41. struct polygon_reverse: private range_reverse
  42. {
  43. template <typename Polygon>
  44. static inline void apply(Polygon& polygon)
  45. {
  46. range_reverse::apply(exterior_ring(polygon));
  47. auto&& rings = interior_rings(polygon);
  48. auto const end = boost::end(rings);
  49. for (auto it = boost::begin(rings); it != end; ++it)
  50. {
  51. range_reverse::apply(*it);
  52. }
  53. }
  54. };
  55. }} // namespace detail::reverse
  56. #endif // DOXYGEN_NO_DETAIL
  57. #ifndef DOXYGEN_NO_DISPATCH
  58. namespace dispatch
  59. {
  60. template <typename Geometry, typename Tag = typename tag<Geometry>::type>
  61. struct reverse
  62. {
  63. static inline void apply(Geometry&)
  64. {}
  65. };
  66. template <typename Ring>
  67. struct reverse<Ring, ring_tag>
  68. : detail::reverse::range_reverse
  69. {};
  70. template <typename LineString>
  71. struct reverse<LineString, linestring_tag>
  72. : detail::reverse::range_reverse
  73. {};
  74. template <typename Polygon>
  75. struct reverse<Polygon, polygon_tag>
  76. : detail::reverse::polygon_reverse
  77. {};
  78. template <typename Geometry>
  79. struct reverse<Geometry, multi_linestring_tag>
  80. : detail::multi_modify<detail::reverse::range_reverse>
  81. {};
  82. template <typename Geometry>
  83. struct reverse<Geometry, multi_polygon_tag>
  84. : detail::multi_modify<detail::reverse::polygon_reverse>
  85. {};
  86. } // namespace dispatch
  87. #endif
  88. namespace resolve_dynamic
  89. {
  90. template <typename Geometry, typename Tag = typename tag<Geometry>::type>
  91. struct reverse
  92. {
  93. static void apply(Geometry& geometry)
  94. {
  95. concepts::check<Geometry>();
  96. dispatch::reverse<Geometry>::apply(geometry);
  97. }
  98. };
  99. template <typename Geometry>
  100. struct reverse<Geometry, dynamic_geometry_tag>
  101. {
  102. static void apply(Geometry& geometry)
  103. {
  104. traits::visit<Geometry>::apply([](auto & g)
  105. {
  106. reverse<util::remove_cref_t<decltype(g)>>::apply(g);
  107. }, geometry);
  108. }
  109. };
  110. template <typename Geometry>
  111. struct reverse<Geometry, geometry_collection_tag>
  112. {
  113. static void apply(Geometry& geometry)
  114. {
  115. detail::visit_breadth_first([](auto & g)
  116. {
  117. reverse<util::remove_cref_t<decltype(g)>>::apply(g);
  118. return true;
  119. }, geometry);
  120. }
  121. };
  122. } // namespace resolve_dynamic
  123. /*!
  124. \brief Reverses the points within a geometry
  125. \details Generic function to reverse a geometry. It resembles the std::reverse
  126. functionality, but it takes the geometry type into account. Only for a ring
  127. or for a linestring it is the same as the std::reverse.
  128. \ingroup reverse
  129. \tparam Geometry \tparam_geometry
  130. \param geometry \param_geometry which will be reversed
  131. \qbk{[include reference/algorithms/reverse.qbk]}
  132. */
  133. template <typename Geometry>
  134. inline void reverse(Geometry& geometry)
  135. {
  136. resolve_dynamic::reverse<Geometry>::apply(geometry);
  137. }
  138. }} // namespace boost::geometry
  139. #endif // BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP