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- //
- // Copyright (c) Chris Glover, 2016.
- //
- //
- // 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)
- //
- #ifndef BOOST_TYPE_INDEX_RUNTIME_CAST_REFERENCE_CAST_HPP
- #define BOOST_TYPE_INDEX_RUNTIME_CAST_REFERENCE_CAST_HPP
- /// \file reference_cast.hpp
- /// \brief Contains the overload of boost::typeindex::runtime_cast for
- /// reference types.
- #include <boost/core/addressof.hpp>
- #include <boost/type_index/runtime_cast/detail/runtime_cast_impl.hpp>
- #include <boost/throw_exception.hpp>
- #include <boost/type_traits/add_reference.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- #include <boost/type_traits/is_base_and_derived.hpp>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- # pragma once
- #endif
- namespace boost { namespace typeindex {
- /// \brief Indicates that runtime_cast was unable to perform the desired cast operation
- /// because the source instance was not also an instance of the target type.
- struct bad_runtime_cast : std::exception
- {};
- /// \brief Safely converts references to classes up, down, and sideways along the inheritance hierarchy.
- /// \tparam T The desired target type. Like dynamic_cast, must be a pointer to complete class type.
- /// \tparam U A complete class type of the source instance, u.
- /// \return If there exists a valid conversion from U& to T, returns a T that references an address
- /// suitably offset from u. If no such conversion exists, throws boost::typeindex::bad_runtime_cast.
- template<typename T, typename U>
- typename boost::add_reference<T>::type runtime_cast(U& u) {
- typedef typename boost::remove_reference<T>::type impl_type;
- impl_type* value = detail::runtime_cast_impl<impl_type>(
- boost::addressof(u), boost::is_base_and_derived<T, U>());
- if(!value)
- BOOST_THROW_EXCEPTION(bad_runtime_cast());
- return *value;
- }
- /// \brief Safely converts references to classes up, down, and sideways along the inheritance hierarchy.
- /// \tparam T The desired target type. Like dynamic_cast, must be a pointer to complete class type.
- /// \tparam U A complete class type of the source instance, u.
- /// \return If there exists a valid conversion from U const& to T const, returns a T const that references an address
- /// suitably offset from u. If no such conversion exists, throws boost::typeindex::bad_runtime_cast.
- template<typename T, typename U>
- typename boost::add_reference<const T>::type runtime_cast(U const& u) {
- typedef typename boost::remove_reference<T>::type impl_type;
- impl_type* value = detail::runtime_cast_impl<impl_type>(
- boost::addressof(u), boost::is_base_and_derived<T, U>());
- if(!value)
- BOOST_THROW_EXCEPTION(bad_runtime_cast());
- return *value;
- }
- }} // namespace boost::typeindex
- #endif // BOOST_TYPE_INDEX_RUNTIME_CAST_REFERENCE_CAST_HPP
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