67 lines
2.8 KiB
C++
67 lines
2.8 KiB
C++
|
//
|
||
|
// 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
|