| // |
| // 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 |