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 2020-2023.
  7. // Modifications copyright (c) 2020-2023 Oracle and/or its affiliates.
  8. // Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
  9. // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  10. // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
  11. // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
  12. // Use, modification and distribution is subject to the Boost Software License,
  13. // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  14. // http://www.boost.org/LICENSE_1_0.txt)
  15. #ifndef BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  16. #define BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  17. #include <algorithm>
  18. #include <boost/range/begin.hpp>
  19. #include <boost/range/end.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. namespace boost { namespace geometry
  28. {
  29. #ifndef DOXYGEN_NO_DETAIL
  30. namespace detail { namespace reverse
  31. {
  32. struct range_reverse
  33. {
  34. template <typename Range>
  35. static inline void apply(Range& range)
  36. {
  37. std::reverse(boost::begin(range), boost::end(range));
  38. }
  39. };
  40. struct polygon_reverse: private range_reverse
  41. {
  42. template <typename Polygon>
  43. static inline void apply(Polygon& polygon)
  44. {
  45. range_reverse::apply(exterior_ring(polygon));
  46. auto&& rings = interior_rings(polygon);
  47. auto const end = boost::end(rings);
  48. for (auto it = boost::begin(rings); it != end; ++it)
  49. {
  50. range_reverse::apply(*it);
  51. }
  52. }
  53. };
  54. }} // namespace detail::reverse
  55. #endif // DOXYGEN_NO_DETAIL
  56. #ifndef DOXYGEN_NO_DISPATCH
  57. namespace dispatch
  58. {
  59. template <typename Geometry, typename Tag = typename tag<Geometry>::type>
  60. struct reverse
  61. {
  62. static inline void apply(Geometry&)
  63. {}
  64. };
  65. template <typename Ring>
  66. struct reverse<Ring, ring_tag>
  67. : detail::reverse::range_reverse
  68. {};
  69. template <typename LineString>
  70. struct reverse<LineString, linestring_tag>
  71. : detail::reverse::range_reverse
  72. {};
  73. template <typename Polygon>
  74. struct reverse<Polygon, polygon_tag>
  75. : detail::reverse::polygon_reverse
  76. {};
  77. template <typename Geometry>
  78. struct reverse<Geometry, multi_linestring_tag>
  79. : detail::multi_modify<detail::reverse::range_reverse>
  80. {};
  81. template <typename Geometry>
  82. struct reverse<Geometry, multi_polygon_tag>
  83. : detail::multi_modify<detail::reverse::polygon_reverse>
  84. {};
  85. } // namespace dispatch
  86. #endif
  87. namespace resolve_dynamic
  88. {
  89. template <typename Geometry, typename Tag = typename tag<Geometry>::type>
  90. struct reverse
  91. {
  92. static void apply(Geometry& geometry)
  93. {
  94. concepts::check<Geometry>();
  95. dispatch::reverse<Geometry>::apply(geometry);
  96. }
  97. };
  98. template <typename Geometry>
  99. struct reverse<Geometry, dynamic_geometry_tag>
  100. {
  101. static void apply(Geometry& geometry)
  102. {
  103. traits::visit<Geometry>::apply([](auto & g)
  104. {
  105. reverse<util::remove_cref_t<decltype(g)>>::apply(g);
  106. }, geometry);
  107. }
  108. };
  109. template <typename Geometry>
  110. struct reverse<Geometry, geometry_collection_tag>
  111. {
  112. static void apply(Geometry& geometry)
  113. {
  114. detail::visit_breadth_first([](auto & g)
  115. {
  116. reverse<util::remove_cref_t<decltype(g)>>::apply(g);
  117. return true;
  118. }, geometry);
  119. }
  120. };
  121. } // namespace resolve_dynamic
  122. /*!
  123. \brief Reverses the points within a geometry
  124. \details Generic function to reverse a geometry. It resembles the std::reverse
  125. functionality, but it takes the geometry type into account. Only for a ring
  126. or for a linestring it is the same as the std::reverse.
  127. \ingroup reverse
  128. \tparam Geometry \tparam_geometry
  129. \param geometry \param_geometry which will be reversed
  130. \qbk{[include reference/algorithms/reverse.qbk]}
  131. */
  132. template <typename Geometry>
  133. inline void reverse(Geometry& geometry)
  134. {
  135. resolve_dynamic::reverse<Geometry>::apply(geometry);
  136. }
  137. }} // namespace boost::geometry
  138. #endif // BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP