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- // Boost.Geometry
- // Copyright (c) 2017 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_STRATEGIES_AREA_RESULT_HPP
- #define BOOST_GEOMETRY_STRATEGIES_AREA_RESULT_HPP
- #include <boost/geometry/core/coordinate_type.hpp>
- #include <boost/geometry/core/cs.hpp>
- #include <boost/geometry/strategies/area.hpp>
- #include <boost/geometry/strategies/default_strategy.hpp>
- #include <boost/geometry/util/select_most_precise.hpp>
- #include <boost/geometry/util/select_sequence_element.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/type_traits/is_same.hpp>
- #include <boost/variant/variant_fwd.hpp>
- namespace boost { namespace geometry
- {
- /*!
- \brief Meta-function defining return type of area function
- \ingroup area
- \note The return-type is defined by Geometry and Strategy
- */
- template
- <
- typename Geometry,
- typename Strategy = default_strategy
- >
- struct area_result
- : Strategy::template result_type<Geometry>
- {};
- template <BOOST_VARIANT_ENUM_PARAMS(typename T), typename Strategy>
- struct area_result<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Strategy>
- : geometry::area_result
- <
- typename geometry::util::select_sequence_element
- <
- typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types
- >::type,
- Strategy
- >
- {};
- template <typename Geometry>
- struct area_result<Geometry, default_strategy>
- : geometry::area_result
- <
- Geometry,
- typename geometry::strategy::area::services::default_strategy
- <
- typename cs_tag<Geometry>::type
- >::type
- >
- {};
- #ifndef DOXYGEN_NO_DETAIL
- namespace detail { namespace area
- {
- template <typename Curr, typename Next>
- struct pred_more_precise_default_area_result
- {
- typedef typename geometry::area_result<Curr, default_strategy>::type curr_result_t;
- typedef typename geometry::area_result<Next, default_strategy>::type next_result_t;
- typedef typename boost::mpl::if_c
- <
- boost::is_same
- <
- curr_result_t,
- typename geometry::select_most_precise
- <
- curr_result_t,
- next_result_t
- >::type
- >::value,
- Curr,
- Next
- >::type type;
- };
- }} // namespace detail::area
- #endif //DOXYGEN_NO_DETAIL
- template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
- struct area_result<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, default_strategy>
- : geometry::area_result
- <
- typename geometry::util::select_sequence_element
- <
- typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types,
- geometry::detail::area::pred_more_precise_default_area_result
- >::type,
- default_strategy
- >
- {};
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_STRATEGIES_AREA_RESULT_HPP
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