reverse.hpp 4.3 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. // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
  7. // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
  8. // Use, modification and distribution is subject to the Boost Software License,
  9. // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  10. // http://www.boost.org/LICENSE_1_0.txt)
  11. #ifndef BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  12. #define BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP
  13. #include <algorithm>
  14. #include <boost/range.hpp>
  15. #include <boost/type_traits/remove_reference.hpp>
  16. #include <boost/variant/apply_visitor.hpp>
  17. #include <boost/variant/static_visitor.hpp>
  18. #include <boost/variant/variant_fwd.hpp>
  19. #include <boost/geometry/algorithms/detail/interior_iterator.hpp>
  20. #include <boost/geometry/algorithms/detail/multi_modify.hpp>
  21. #include <boost/geometry/core/interior_rings.hpp>
  22. #include <boost/geometry/core/tags.hpp>
  23. #include <boost/geometry/geometries/concepts/check.hpp>
  24. namespace boost { namespace geometry
  25. {
  26. #ifndef DOXYGEN_NO_DETAIL
  27. namespace detail { namespace reverse
  28. {
  29. struct range_reverse
  30. {
  31. template <typename Range>
  32. static inline void apply(Range& range)
  33. {
  34. std::reverse(boost::begin(range), boost::end(range));
  35. }
  36. };
  37. struct polygon_reverse: private range_reverse
  38. {
  39. template <typename Polygon>
  40. static inline void apply(Polygon& polygon)
  41. {
  42. range_reverse::apply(exterior_ring(polygon));
  43. typename interior_return_type<Polygon>::type
  44. rings = interior_rings(polygon);
  45. for (typename detail::interior_iterator<Polygon>::type
  46. it = boost::begin(rings); it != boost::end(rings); ++it)
  47. {
  48. range_reverse::apply(*it);
  49. }
  50. }
  51. };
  52. }} // namespace detail::reverse
  53. #endif // DOXYGEN_NO_DETAIL
  54. #ifndef DOXYGEN_NO_DISPATCH
  55. namespace dispatch
  56. {
  57. template <typename Geometry, typename Tag = typename tag<Geometry>::type>
  58. struct reverse
  59. {
  60. static inline void apply(Geometry&)
  61. {}
  62. };
  63. template <typename Ring>
  64. struct reverse<Ring, ring_tag>
  65. : detail::reverse::range_reverse
  66. {};
  67. template <typename LineString>
  68. struct reverse<LineString, linestring_tag>
  69. : detail::reverse::range_reverse
  70. {};
  71. template <typename Polygon>
  72. struct reverse<Polygon, polygon_tag>
  73. : detail::reverse::polygon_reverse
  74. {};
  75. template <typename Geometry>
  76. struct reverse<Geometry, multi_linestring_tag>
  77. : detail::multi_modify
  78. <
  79. Geometry,
  80. detail::reverse::range_reverse
  81. >
  82. {};
  83. template <typename Geometry>
  84. struct reverse<Geometry, multi_polygon_tag>
  85. : detail::multi_modify
  86. <
  87. Geometry,
  88. detail::reverse::polygon_reverse
  89. >
  90. {};
  91. } // namespace dispatch
  92. #endif
  93. namespace resolve_variant
  94. {
  95. template <typename Geometry>
  96. struct reverse
  97. {
  98. static void apply(Geometry& geometry)
  99. {
  100. concepts::check<Geometry>();
  101. dispatch::reverse<Geometry>::apply(geometry);
  102. }
  103. };
  104. template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
  105. struct reverse<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
  106. {
  107. struct visitor: boost::static_visitor<void>
  108. {
  109. template <typename Geometry>
  110. void operator()(Geometry& geometry) const
  111. {
  112. reverse<Geometry>::apply(geometry);
  113. }
  114. };
  115. static inline void apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>& geometry)
  116. {
  117. boost::apply_visitor(visitor(), geometry);
  118. }
  119. };
  120. } // namespace resolve_variant
  121. /*!
  122. \brief Reverses the points within a geometry
  123. \details Generic function to reverse a geometry. It resembles the std::reverse
  124. functionality, but it takes the geometry type into account. Only for a ring
  125. or for a linestring it is the same as the std::reverse.
  126. \ingroup reverse
  127. \tparam Geometry \tparam_geometry
  128. \param geometry \param_geometry which will be reversed
  129. \qbk{[include reference/algorithms/reverse.qbk]}
  130. */
  131. template <typename Geometry>
  132. inline void reverse(Geometry& geometry)
  133. {
  134. resolve_variant::reverse<Geometry>::apply(geometry);
  135. }
  136. }} // namespace boost::geometry
  137. #endif // BOOST_GEOMETRY_ALGORITHMS_REVERSE_HPP