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Diffstat (limited to 'boost/geometry/strategies/distance_result.hpp')
| -rw-r--r-- | boost/geometry/strategies/distance_result.hpp | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/boost/geometry/strategies/distance_result.hpp b/boost/geometry/strategies/distance_result.hpp new file mode 100644 index 0000000000..185a511464 --- /dev/null +++ b/boost/geometry/strategies/distance_result.hpp @@ -0,0 +1,213 @@ +// Boost.Geometry (aka GGL, Generic Geometry Library) + +// Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands. +// Copyright (c) 2008-2014 Bruno Lalande, Paris, France. +// Copyright (c) 2009-2014 Mateusz Loskot, London, UK. +// Copyright (c) 2013-2014 Adam Wulkiewicz, Lodz, Poland. +// Copyright (c) 2014 Samuel Debionne, Grenoble, France. + +// This file was modified by Oracle on 2014. +// Modifications copyright (c) 2014, Oracle and/or its affiliates. + +// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle + +// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library +// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. + +// 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_DISTANCE_RESULT_HPP +#define BOOST_GEOMETRY_STRATEGIES_DISTANCE_RESULT_HPP + +#include <boost/mpl/always.hpp> +#include <boost/mpl/bool.hpp> +#include <boost/mpl/vector.hpp> + +#include <boost/variant/variant_fwd.hpp> + +#include <boost/geometry/core/point_type.hpp> + +#include <boost/geometry/strategies/default_strategy.hpp> +#include <boost/geometry/strategies/distance.hpp> + +#include <boost/geometry/util/compress_variant.hpp> +#include <boost/geometry/util/transform_variant.hpp> +#include <boost/geometry/util/combine_if.hpp> + +#include <boost/geometry/algorithms/detail/distance/default_strategies.hpp> + + +namespace boost { namespace geometry +{ + + +namespace resolve_strategy +{ + +template <typename Geometry1, typename Geometry2, typename Strategy> +struct distance_result + : strategy::distance::services::return_type + < + Strategy, + typename point_type<Geometry1>::type, + typename point_type<Geometry2>::type + > +{}; + +template <typename Geometry1, typename Geometry2> +struct distance_result<Geometry1, Geometry2, default_strategy> + : distance_result + < + Geometry1, + Geometry2, + typename detail::distance::default_strategy + < + Geometry1, Geometry2 + >::type + > +{}; + +} // namespace resolve_strategy + + +namespace resolve_variant +{ + +template <typename Geometry1, typename Geometry2, typename Strategy> +struct distance_result + : resolve_strategy::distance_result + < + Geometry1, + Geometry2, + Strategy + > +{}; + + +template +< + typename Geometry1, + BOOST_VARIANT_ENUM_PARAMS(typename T), + typename Strategy +> +struct distance_result + < + Geometry1, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Strategy + > +{ + // A set of all variant type combinations that are compatible and + // implemented + typedef typename util::combine_if< + typename mpl::vector1<Geometry1>, + typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types, + // Here we want should remove most of the combinations that + // are not valid, mostly to limit the size of the resulting MPL set. + // But is_implementedn is not ready for prime time + // + // util::is_implemented2<mpl::_1, mpl::_2, dispatch::distance<mpl::_1, mpl::_2> > + mpl::always<mpl::true_> + >::type possible_input_types; + + // The (possibly variant) result type resulting from these combinations + typedef typename compress_variant< + typename transform_variant< + possible_input_types, + resolve_strategy::distance_result< + mpl::first<mpl::_>, + mpl::second<mpl::_>, + Strategy + >, + mpl::back_inserter<mpl::vector0<> > + >::type + >::type type; +}; + + +// Distance arguments are commutative +template +< + BOOST_VARIANT_ENUM_PARAMS(typename T), + typename Geometry2, + typename Strategy +> +struct distance_result + < + boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, + Geometry2, + Strategy + > : public distance_result + < + Geometry2, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Strategy + > +{}; + + +template <BOOST_VARIANT_ENUM_PARAMS(typename T), typename Strategy> +struct distance_result + < + boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, + boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, + Strategy + > +{ + // A set of all variant type combinations that are compatible and + // implemented + typedef typename util::combine_if + < + typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types, + typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types, + // Here we want to try to remove most of the combinations + // that are not valid, mostly to limit the size of the + // resulting MPL vector. + // But is_implemented is not ready for prime time + // + // util::is_implemented2<mpl::_1, mpl::_2, dispatch::distance<mpl::_1, mpl::_2> > + mpl::always<mpl::true_> + >::type possible_input_types; + + // The (possibly variant) result type resulting from these combinations + typedef typename compress_variant< + typename transform_variant< + possible_input_types, + resolve_strategy::distance_result< + mpl::first<mpl::_>, + mpl::second<mpl::_>, + Strategy + >, + mpl::back_inserter<mpl::vector0<> > + >::type + >::type type; +}; + +} // namespace resolve_variant + + +/*! +\brief Meta-function defining return type of distance function +\ingroup distance +\note The strategy defines the return-type (so this situation is different + from length, where distance is sqr/sqrt, but length always squared) + */ +template +< + typename Geometry1, + typename Geometry2 = Geometry1, + typename Strategy = void +> +struct distance_result + : resolve_variant::distance_result<Geometry1, Geometry2, Strategy> +{}; + + +template <typename Geometry1, typename Geometry2> +struct distance_result<Geometry1, Geometry2, void> + : distance_result<Geometry1, Geometry2, default_strategy> +{}; + + +}} // namespace boost::geometry + + +#endif // BOOST_GEOMETRY_STRATEGIES_DISTANCE_RESULT_HPP |