Chris@16: // Boost.Geometry Index
Chris@16: //
Chris@101: // Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
Chris@16: //
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_INDEX_INDEXABLE_HPP
Chris@16: #define BOOST_GEOMETRY_INDEX_INDEXABLE_HPP
Chris@16: 
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: 
Chris@101: namespace boost { namespace geometry { namespace index { namespace detail {
Chris@16: 
Chris@16: template <typename Geometry, typename GeometryTag>
Chris@16: struct is_indexable_impl { static const bool value = false; };
Chris@16: 
Chris@16: template <typename Point>
Chris@16: struct is_indexable_impl<Point, geometry::point_tag> { static const bool value = true; };
Chris@16: 
Chris@16: template <typename Box>
Chris@16: struct is_indexable_impl<Box, geometry::box_tag> { static const bool value = true; };
Chris@16: 
Chris@101: template <typename Segment>
Chris@101: struct is_indexable_impl<Segment, geometry::segment_tag> { static const bool value = true; };
Chris@101: 
Chris@16: template <typename Indexable>
Chris@16: struct is_indexable
Chris@16: {
Chris@16:     static const bool value =
Chris@101:         is_indexable_impl
Chris@101:             <
Chris@101:                 Indexable,
Chris@101:                 typename geometry::tag<Indexable>::type
Chris@101:             >::value;
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16: \brief The function object extracting Indexable from Value.
Chris@16: 
Chris@16: It translates Value object to Indexable object. The default version handles Values which are Indexables.
Chris@101: This template is also specialized for std::pair<Indexable, T2>, boost::tuple<Indexable, ...>
Chris@101: and std::tuple<Indexable, ...>.
Chris@16: 
Chris@16: \tparam Value       The Value type which may be translated directly to the Indexable.
Chris@101: \tparam IsIndexable If true, the const reference to Value is returned.
Chris@16: */
Chris@101: template <typename Value, bool IsIndexable = is_indexable<Value>::value>
Chris@16: struct indexable
Chris@16: {
Chris@16:     BOOST_MPL_ASSERT_MSG(
Chris@16:         (detail::is_indexable<Value>::value),
Chris@16:         NOT_VALID_INDEXABLE_TYPE,
Chris@16:         (Value)
Chris@16:     );
Chris@101: 
Chris@16:     /*! \brief The type of result returned by function object. */
Chris@16:     typedef Value const& result_type;
Chris@16: 
Chris@16:     /*!
Chris@16:     \brief Return indexable extracted from the value.
Chris@16:     
Chris@16:     \param v The value.
Chris@16:     \return The indexable.
Chris@16:     */
Chris@101:     inline result_type operator()(Value const& v) const
Chris@16:     {
Chris@16:         return v;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16: \brief The function object extracting Indexable from Value.
Chris@16: 
Chris@16: This specialization translates from std::pair<Indexable, T2>.
Chris@16: 
Chris@16: \tparam Indexable       The Indexable type.
Chris@16: \tparam T2              The second type.
Chris@16: */
Chris@16: template <typename Indexable, typename T2>
Chris@101: struct indexable<std::pair<Indexable, T2>, false>
Chris@16: {
Chris@16:     BOOST_MPL_ASSERT_MSG(
Chris@16:         (detail::is_indexable<Indexable>::value),
Chris@16:         NOT_VALID_INDEXABLE_TYPE,
Chris@16:         (Indexable)
Chris@16:     );
Chris@16: 
Chris@16:     /*! \brief The type of result returned by function object. */
Chris@16:     typedef Indexable const& result_type;
Chris@16: 
Chris@16:     /*!
Chris@16:     \brief Return indexable extracted from the value.
Chris@16:     
Chris@16:     \param v The value.
Chris@16:     \return The indexable.
Chris@16:     */
Chris@101:     inline result_type operator()(std::pair<Indexable, T2> const& v) const
Chris@16:     {
Chris@16:         return v.first;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16: \brief The function object extracting Indexable from Value.
Chris@16: 
Chris@16: This specialization translates from boost::tuple<Indexable, ...>.
Chris@16: 
Chris@16: \tparam Indexable   The Indexable type.
Chris@16: */
Chris@16: template <typename Indexable, typename T1, typename T2, typename T3, typename T4,
Chris@16:           typename T5, typename T6, typename T7, typename T8, typename T9>
Chris@101: struct indexable<boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9>, false>
Chris@16: {
Chris@16:     typedef boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9> value_type;
Chris@16: 
Chris@16:     BOOST_MPL_ASSERT_MSG(
Chris@16:         (detail::is_indexable<Indexable>::value),
Chris@16:         NOT_VALID_INDEXABLE_TYPE,
Chris@16:         (Indexable)
Chris@16:         );
Chris@16: 
Chris@16:     /*! \brief The type of result returned by function object. */
Chris@16:     typedef Indexable const& result_type;
Chris@16: 
Chris@16:     /*!
Chris@16:     \brief Return indexable extracted from the value.
Chris@16:     
Chris@16:     \param v The value.
Chris@16:     \return The indexable.
Chris@16:     */
Chris@101:     inline result_type operator()(value_type const& v) const
Chris@16:     {
Chris@16:         return boost::get<0>(v);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@101: }}}} // namespace boost::geometry::index::detail
Chris@16: 
Chris@16: #if !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@16: #include <tuple>
Chris@16: 
Chris@101: namespace boost { namespace geometry { namespace index { namespace detail {
Chris@16: 
Chris@16: /*!
Chris@16: \brief The function object extracting Indexable from Value.
Chris@16: 
Chris@16: This specialization translates from std::tuple<Indexable, Args...>.
Chris@16: It's defined if the compiler supports tuples and variadic templates.
Chris@16: 
Chris@16: \tparam Indexable   The Indexable type.
Chris@16: */
Chris@16: template <typename Indexable, typename ...Args>
Chris@101: struct indexable<std::tuple<Indexable, Args...>, false>
Chris@16: {
Chris@16:     typedef std::tuple<Indexable, Args...> value_type;
Chris@16: 
Chris@16:     BOOST_MPL_ASSERT_MSG(
Chris@16:         (detail::is_indexable<Indexable>::value),
Chris@16:         NOT_VALID_INDEXABLE_TYPE,
Chris@16:         (Indexable)
Chris@16:         );
Chris@16: 
Chris@16:     /*! \brief The type of result returned by function object. */
Chris@16:     typedef Indexable const& result_type;
Chris@16: 
Chris@16:     /*!
Chris@16:     \brief Return indexable extracted from the value.
Chris@16:     
Chris@16:     \param v The value.
Chris@16:     \return The indexable.
Chris@16:     */
Chris@16:     result_type operator()(value_type const& v) const
Chris@16:     {
Chris@16:         return std::get<0>(v);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@101: }}}} // namespace boost::geometry::index::detail
Chris@16: 
Chris@16: #endif // !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@101: namespace boost { namespace geometry { namespace index {
Chris@101: 
Chris@101: /*!
Chris@101: \brief The function object extracting Indexable from Value.
Chris@101: 
Chris@101: It translates Value object to Indexable object. By default, it can handle Values which are Indexables,
Chris@101: std::pair<Indexable, T2>, boost::tuple<Indexable, ...> and std::tuple<Indexable, ...> if STD tuples
Chris@101: and variadic templates are supported.
Chris@101: 
Chris@101: \tparam Value       The Value type which may be translated directly to the Indexable.
Chris@101: */
Chris@101: template <typename Value>
Chris@101: struct indexable
Chris@101:     : detail::indexable<Value>
Chris@101: {
Chris@101:     /*! \brief The type of result returned by function object. It should be const Indexable reference. */
Chris@101:     typedef typename detail::indexable<Value>::result_type result_type;
Chris@101: 
Chris@101:     /*!
Chris@101:     \brief Return indexable extracted from the value.
Chris@101:     
Chris@101:     \param v The value.
Chris@101:     \return The indexable.
Chris@101:     */
Chris@101:     inline result_type operator()(Value const& v) const
Chris@101:     {
Chris@101:         return detail::indexable<Value>::operator()(v);
Chris@101:     }
Chris@101: };
Chris@101: 
Chris@101: }}} // namespace boost::geometry::index
Chris@101: 
Chris@16: #endif // BOOST_GEOMETRY_INDEX_INDEXABLE_HPP