197 lines
5.7 KiB
C++
197 lines
5.7 KiB
C++
// Boost.Geometry Index
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//
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// Copyright (c) 2011-2015 Adam Wulkiewicz, Lodz, Poland.
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//
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_INDEX_INDEXABLE_HPP
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#define BOOST_GEOMETRY_INDEX_INDEXABLE_HPP
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#include <boost/mpl/assert.hpp>
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#include <boost/geometry/index/detail/is_indexable.hpp>
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namespace boost { namespace geometry { namespace index { namespace detail {
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/*!
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\brief The function object extracting Indexable from Value.
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It translates Value object to Indexable object. The default version handles Values which are Indexables.
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This template is also specialized for std::pair<Indexable, T2>, boost::tuple<Indexable, ...>
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and std::tuple<Indexable, ...>.
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\tparam Value The Value type which may be translated directly to the Indexable.
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\tparam IsIndexable If true, the const reference to Value is returned.
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*/
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template <typename Value, bool IsIndexable = is_indexable<Value>::value>
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struct indexable
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{
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BOOST_MPL_ASSERT_MSG(
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(detail::is_indexable<Value>::value),
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NOT_VALID_INDEXABLE_TYPE,
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(Value)
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);
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/*! \brief The type of result returned by function object. */
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typedef Value const& result_type;
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/*!
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\brief Return indexable extracted from the value.
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\param v The value.
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\return The indexable.
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*/
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inline result_type operator()(Value const& v) const
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{
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return v;
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}
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};
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/*!
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\brief The function object extracting Indexable from Value.
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This specialization translates from std::pair<Indexable, T2>.
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\tparam Indexable The Indexable type.
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\tparam T2 The second type.
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*/
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template <typename Indexable, typename T2>
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struct indexable<std::pair<Indexable, T2>, false>
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{
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BOOST_MPL_ASSERT_MSG(
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(detail::is_indexable<Indexable>::value),
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NOT_VALID_INDEXABLE_TYPE,
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(Indexable)
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);
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/*! \brief The type of result returned by function object. */
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typedef Indexable const& result_type;
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/*!
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\brief Return indexable extracted from the value.
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\param v The value.
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\return The indexable.
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*/
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inline result_type operator()(std::pair<Indexable, T2> const& v) const
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{
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return v.first;
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}
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};
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/*!
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\brief The function object extracting Indexable from Value.
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This specialization translates from boost::tuple<Indexable, ...>.
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\tparam Indexable The Indexable type.
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*/
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template <typename Indexable, typename T1, typename T2, typename T3, typename T4,
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typename T5, typename T6, typename T7, typename T8, typename T9>
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struct indexable<boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9>, false>
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{
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typedef boost::tuple<Indexable, T1, T2, T3, T4, T5, T6, T7, T8, T9> value_type;
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BOOST_MPL_ASSERT_MSG(
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(detail::is_indexable<Indexable>::value),
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NOT_VALID_INDEXABLE_TYPE,
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(Indexable)
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);
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/*! \brief The type of result returned by function object. */
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typedef Indexable const& result_type;
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/*!
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\brief Return indexable extracted from the value.
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\param v The value.
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\return The indexable.
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*/
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inline result_type operator()(value_type const& v) const
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{
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return boost::get<0>(v);
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}
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};
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}}}} // namespace boost::geometry::index::detail
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#if !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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#include <tuple>
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namespace boost { namespace geometry { namespace index { namespace detail {
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/*!
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\brief The function object extracting Indexable from Value.
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This specialization translates from std::tuple<Indexable, Args...>.
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It's defined if the compiler supports tuples and variadic templates.
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\tparam Indexable The Indexable type.
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*/
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template <typename Indexable, typename ...Args>
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struct indexable<std::tuple<Indexable, Args...>, false>
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{
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typedef std::tuple<Indexable, Args...> value_type;
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BOOST_MPL_ASSERT_MSG(
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(detail::is_indexable<Indexable>::value),
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NOT_VALID_INDEXABLE_TYPE,
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(Indexable)
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);
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/*! \brief The type of result returned by function object. */
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typedef Indexable const& result_type;
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/*!
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\brief Return indexable extracted from the value.
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\param v The value.
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\return The indexable.
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*/
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result_type operator()(value_type const& v) const
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{
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return std::get<0>(v);
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}
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};
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}}}} // namespace boost::geometry::index::detail
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#endif // !defined(BOOST_NO_CXX11_HDR_TUPLE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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namespace boost { namespace geometry { namespace index {
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/*!
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\brief The function object extracting Indexable from Value.
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It translates Value object to Indexable object. By default, it can handle Values which are Indexables,
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std::pair<Indexable, T2>, boost::tuple<Indexable, ...> and std::tuple<Indexable, ...> if STD tuples
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and variadic templates are supported.
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\tparam Value The Value type which may be translated directly to the Indexable.
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*/
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template <typename Value>
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struct indexable
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: detail::indexable<Value>
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{
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/*! \brief The type of result returned by function object. It should be const Indexable reference. */
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typedef typename detail::indexable<Value>::result_type result_type;
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/*!
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\brief Return indexable extracted from the value.
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\param v The value.
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\return The indexable.
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*/
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inline result_type operator()(Value const& v) const
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{
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return detail::indexable<Value>::operator()(v);
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}
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};
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}}} // namespace boost::geometry::index
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#endif // BOOST_GEOMETRY_INDEX_INDEXABLE_HPP
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