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- // Boost.TypeErasure library
- //
- // Copyright 2015 Steven Watanabe
- //
- // Distributed under 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)
- //
- // $Id$
- #ifndef BOOST_TYPE_ERASURE_DYNAMIC_ANY_CAST_HPP_INCLUDED
- #define BOOST_TYPE_ERASURE_DYNAMIC_ANY_CAST_HPP_INCLUDED
- #include <boost/type_erasure/detail/normalize.hpp>
- #include <boost/type_erasure/binding_of.hpp>
- #include <boost/type_erasure/static_binding.hpp>
- #include <boost/type_erasure/dynamic_binding.hpp>
- #include <boost/type_erasure/concept_of.hpp>
- #include <boost/type_erasure/placeholder_of.hpp>
- #include <boost/type_erasure/any.hpp>
- #include <boost/type_erasure/binding.hpp>
- #include <boost/mpl/vector.hpp>
- #include <boost/mpl/set.hpp>
- #include <boost/mpl/fold.hpp>
- #include <boost/type_traits/add_const.hpp>
- #include <boost/type_traits/add_reference.hpp>
- #include <boost/type_traits/remove_const.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- namespace boost {
- namespace type_erasure {
- namespace detail {
- template<class P, class P2, class Any>
- struct make_ref_placeholder;
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2, const Any&> { typedef const P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2, Any&> { typedef P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&, const Any&> { typedef P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&, Any&> { typedef P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, const P2&, const Any&> { typedef const P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, const P2&, Any&> { typedef const P& type; };
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- template<class P, class P2, class Any>
- struct make_ref_placeholder { typedef P&& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&, Any> { typedef P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, const P2&, Any> { typedef const P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&&, Any> { typedef P&& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&&, const Any&> { typedef const P& type; };
- template<class P, class P2, class Any>
- struct make_ref_placeholder<P, P2&&, Any&> { typedef P& type; };
- #endif
- template<class R, class Tag>
- struct make_result_placeholder_map
- {
- typedef ::boost::mpl::map<
- ::boost::mpl::pair<
- typename ::boost::remove_const<
- typename ::boost::remove_reference<
- typename ::boost::type_erasure::placeholder_of<R>::type
- >::type
- >::type,
- typename ::boost::remove_const<
- typename ::boost::remove_reference<
- Tag
- >::type
- >::type
- >
- > type;
- };
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- template<class R, class Any, class Map>
- R dynamic_any_cast_impl(Any&& arg, const static_binding<Map>& map)
- #else
- template<class R, class Any, class Map>
- R dynamic_any_cast_impl(Any& arg, const static_binding<Map>& map)
- #endif
- {
- typedef typename ::boost::remove_const<typename ::boost::remove_reference<Any>::type>::type src_type;
- typedef typename ::boost::type_erasure::detail::normalize_concept<
- typename ::boost::type_erasure::concept_of<src_type>::type
- >::type normalized;
- typedef typename ::boost::mpl::fold<
- normalized,
- #ifndef BOOST_TYPE_ERASURE_USE_MP11
- ::boost::mpl::set0<>,
- #else
- ::boost::mp11::mp_list<>,
- #endif
- ::boost::type_erasure::detail::get_placeholders<
- ::boost::mpl::_2,
- ::boost::mpl::_1
- >
- >::type placeholders;
- #ifndef BOOST_TYPE_ERASURE_USE_MP11
- typedef ::boost::type_erasure::detail::substitution_map< ::boost::mpl::map0<> > identity_map;
- #else
- typedef ::boost::type_erasure::detail::make_identity_placeholder_map<normalized> identity_map;
- #endif
- ::boost::type_erasure::dynamic_binding<placeholders> my_binding(
- ::boost::type_erasure::binding_of(arg),
- ::boost::type_erasure::make_binding<identity_map>());
- typedef typename ::boost::remove_const<
- typename ::boost::remove_reference<
- typename ::boost::type_erasure::placeholder_of<R>::type
- >::type
- >::type result_placeholder;
- ::boost::type_erasure::binding< typename ::boost::type_erasure::concept_of<R>::type> new_binding(
- my_binding,
- map);
- typedef ::boost::type_erasure::any<
- typename ::boost::type_erasure::concept_of<R>::type,
- typename ::boost::type_erasure::detail::make_ref_placeholder<
- result_placeholder,
- typename ::boost::type_erasure::placeholder_of<src_type>::type,
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- Any
- #else
- Any&
- #endif
- >::type
- > result_ref_type;
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- return result_ref_type(std::forward<Any>(arg), new_binding);
- #else
- return result_ref_type(arg, new_binding);
- #endif
- }
- }
- #ifdef BOOST_TYPE_ERASURE_DOXYGEN
- /**
- * Downcasts or crosscasts an @ref any.
- *
- * \pre @c R and @c Any must both be specializations of @ref any.
- * \pre PlaceholderMap must be an MPL map with a key
- * for every non-deduced placeholder used by R.
- * The value associated with each key should
- * be the corresponding placeholder in Any.
- * \pre The concept of Any must include @ref typeid_, for every
- * @ref placeholder which is used by R.
- *
- * The single argument form can only be used when @c R uses
- * a single non-deduced placeholder.
- *
- * \throws bad_any_cast if the concepts used by R were
- * not previously registered via a call to
- * \register_binding.
- *
- * Example:
- * \code
- * // Assume that typeid_<>, copy_constructible<>, and incrementable<>
- * // have all been registered for int.
- * any<mpl::vector<typeid_<>, copy_constructible<> > > x(1);
- * typedef any<
- * mpl::vector<
- * typeid_<>,
- * copy_constructible<>,
- * incrementable<>
- * >
- * > incrementable_any;
- * auto y = dynamic_any_cast<incrementable_any>(x);
- * ++y;
- * assert(any_cast<int>(y) == 2);
- * \endcode
- */
- template<class R, class Any>
- R dynamic_any_cast(Any&& arg);
- /**
- * \overload
- */
- template<class R, class Any, class Map>
- R dynamic_any_cast(Any&& arg, const static_binding<Map>&);
- #else
- template<class R, class Concept, class Tag>
- R dynamic_any_cast(const any<Concept, Tag>& arg)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(arg,
- ::boost::type_erasure::make_binding<typename ::boost::type_erasure::detail::make_result_placeholder_map<R, Tag>::type>());
- }
- template<class R, class Concept, class Tag>
- R dynamic_any_cast(any<Concept, Tag>& arg)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(arg,
- ::boost::type_erasure::make_binding<typename ::boost::type_erasure::detail::make_result_placeholder_map<R, Tag>::type>());
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- template<class R, class Concept, class Tag>
- R dynamic_any_cast(any<Concept, Tag>&& arg)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(::std::move(arg),
- ::boost::type_erasure::make_binding<typename ::boost::type_erasure::detail::make_result_placeholder_map<R, Tag>::type>());
- }
- #endif
- template<class R, class Concept, class Tag, class Map>
- R dynamic_any_cast(const any<Concept, Tag>& arg, const static_binding<Map>& map)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(arg, map);
- }
- template<class R, class Concept, class Tag, class Map>
- R dynamic_any_cast(any<Concept, Tag>& arg, const static_binding<Map>& map)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(arg, map);
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- template<class R, class Concept, class Tag, class Map>
- R dynamic_any_cast(any<Concept, Tag>&& arg, const static_binding<Map>& map)
- {
- return ::boost::type_erasure::detail::dynamic_any_cast_impl<R>(::std::move(arg), map);
- }
- #endif
- #endif
- }
- }
- #endif
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