| // Boost.Geometry Index |
| // |
| // Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland. |
| // |
| // Use, modification and distribution is subject to the Boost Software License, |
| // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_GEOMETRY_INDEX_INDEXABLE_HPP |
| #define BOOST_GEOMETRY_INDEX_INDEXABLE_HPP |
| |
| #include <boost/mpl/assert.hpp> |
| |
| namespace boost { namespace geometry { namespace index { namespace detail { |
| |
| template <typename Geometry, typename GeometryTag> |
| struct is_indexable_impl { static const bool value = false; }; |
| |
| template <typename Point> |
| struct is_indexable_impl<Point, geometry::point_tag> { static const bool value = true; }; |
| |
| template <typename Box> |
| struct is_indexable_impl<Box, geometry::box_tag> { static const bool value = true; }; |
| |
| template <typename Segment> |
| struct is_indexable_impl<Segment, geometry::segment_tag> { static const bool value = true; }; |
| |
| template <typename Indexable> |
| struct is_indexable |
| { |
| static const bool value = |
| is_indexable_impl |
| < |
| Indexable, |
| typename geometry::tag<Indexable>::type |
| >::value; |
| }; |
| |
| /*! |
| \brief The function object extracting Indexable from Value. |
| |
| It translates Value object to Indexable object. The default version handles Values which are Indexables. |
| This template is also specialized for std::pair<Indexable, T2>, boost::tuple<Indexable, ...> |
| and std::tuple<Indexable, ...>. |
| |
| \tparam Value The Value type which may be translated directly to the Indexable. |
| \tparam IsIndexable If true, the const reference to Value is returned. |
| */ |
| template <typename Value, bool IsIndexable = is_indexable<Value>::value> |
| struct indexable |
| { |
| BOOST_MPL_ASSERT_MSG( |
| (detail::is_indexable<Value>::value), |
| NOT_VALID_INDEXABLE_TYPE, |
| (Value) |
| ); |
| |
| /*! \brief The type of result returned by function object. */ |
| typedef Value const& result_type; |
| |
| /*! |
| \brief Return indexable extracted from the value. |
| |
| \param v The value. |
| \return The indexable. |
| */ |
| inline result_type operator()(Value const& v) const |
| { |
| return v; |
| } |
| }; |
| |
| /*! |
| \brief The function object extracting Indexable from Value. |
| |
| This specialization translates from std::pair<Indexable, T2>. |
| |
| \tparam Indexable The Indexable type. |
| \tparam T2 The second type. |
| */ |
| template <typename Indexable, typename T2> |
| struct indexable<std::pair<Indexable, T2>, false> |
| { |
| BOOST_MPL_ASSERT_MSG( |
| (detail::is_indexable<Indexable>::value), |
| NOT_VALID_INDEXABLE_TYPE, |
| (Indexable) |
| ); |
| |
| /*! \brief The type of result returned by function object. */ |
| typedef Indexable const& result_type; |
| |
| /*! |
| \brief Return indexable extracted from the value. |
| |
| \param v The value. |
| \return The indexable. |
| */ |
| inline result_type operator()(std::pair<Indexable, T2> const& v) const |
| { |
| return v.first; |
| } |
| }; |
| |
| /*! |
| \brief The function object extracting Indexable from Value. |
| |
| This specialization translates from boost::tuple<Indexable, ...>. |
| |
| \tparam Indexable The Indexable type. |
| */ |
| template <typename Indexable, typename T1, typename T2, typename T3, typename T4, |
| typename T5, typename T6, typename T7, typename T8, typename T9> |
| struct indexable<boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9>, false> |
| { |
| typedef boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9> value_type; |
| |
| BOOST_MPL_ASSERT_MSG( |
| (detail::is_indexable<Indexable>::value), |
| NOT_VALID_INDEXABLE_TYPE, |
| (Indexable) |
| ); |
| |
| /*! \brief The type of result returned by function object. */ |
| typedef Indexable const& result_type; |
| |
| /*! |
| \brief Return indexable extracted from the value. |
| |
| \param v The value. |
| \return The indexable. |
| */ |
| inline result_type operator()(value_type const& v) const |
| { |
| return boost::get<0>(v); |
| } |
| }; |
| |
| }}}} // namespace boost::geometry::index::detail |
| |
| #if !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) |
| |
| #include <tuple> |
| |
| namespace boost { namespace geometry { namespace index { namespace detail { |
| |
| /*! |
| \brief The function object extracting Indexable from Value. |
| |
| This specialization translates from std::tuple<Indexable, Args...>. |
| It's defined if the compiler supports tuples and variadic templates. |
| |
| \tparam Indexable The Indexable type. |
| */ |
| template <typename Indexable, typename ...Args> |
| struct indexable<std::tuple<Indexable, Args...>, false> |
| { |
| typedef std::tuple<Indexable, Args...> value_type; |
| |
| BOOST_MPL_ASSERT_MSG( |
| (detail::is_indexable<Indexable>::value), |
| NOT_VALID_INDEXABLE_TYPE, |
| (Indexable) |
| ); |
| |
| /*! \brief The type of result returned by function object. */ |
| typedef Indexable const& result_type; |
| |
| /*! |
| \brief Return indexable extracted from the value. |
| |
| \param v The value. |
| \return The indexable. |
| */ |
| result_type operator()(value_type const& v) const |
| { |
| return std::get<0>(v); |
| } |
| }; |
| |
| }}}} // namespace boost::geometry::index::detail |
| |
| #endif // !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) |
| |
| namespace boost { namespace geometry { namespace index { |
| |
| /*! |
| \brief The function object extracting Indexable from Value. |
| |
| It translates Value object to Indexable object. By default, it can handle Values which are Indexables, |
| std::pair<Indexable, T2>, boost::tuple<Indexable, ...> and std::tuple<Indexable, ...> if STD tuples |
| and variadic templates are supported. |
| |
| \tparam Value The Value type which may be translated directly to the Indexable. |
| */ |
| template <typename Value> |
| struct indexable |
| : detail::indexable<Value> |
| { |
| /*! \brief The type of result returned by function object. It should be const Indexable reference. */ |
| typedef typename detail::indexable<Value>::result_type result_type; |
| |
| /*! |
| \brief Return indexable extracted from the value. |
| |
| \param v The value. |
| \return The indexable. |
| */ |
| inline result_type operator()(Value const& v) const |
| { |
| return detail::indexable<Value>::operator()(v); |
| } |
| }; |
| |
| }}} // namespace boost::geometry::index |
| |
| #endif // BOOST_GEOMETRY_INDEX_INDEXABLE_HPP |