| #ifndef BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED |
| #define BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED |
| |
| // |
| // Copyright 2015 Peter Dimov |
| // |
| // 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 |
| // |
| |
| #include <boost/type_traits/detail/common_arithmetic_type.hpp> |
| #include <boost/type_traits/detail/composite_pointer_type.hpp> |
| #include <boost/type_traits/detail/composite_member_pointer_type.hpp> |
| #include <boost/type_traits/type_identity.hpp> |
| #include <boost/type_traits/is_class.hpp> |
| #include <boost/type_traits/is_union.hpp> |
| #include <boost/type_traits/is_convertible.hpp> |
| #include <boost/type_traits/is_pointer.hpp> |
| #include <boost/type_traits/is_member_pointer.hpp> |
| #include <boost/type_traits/conditional.hpp> |
| |
| namespace boost |
| { |
| |
| namespace type_traits_detail |
| { |
| |
| // the arguments to common_type_impl have already been passed through decay<> |
| |
| template<class T, class U> struct common_type_impl; |
| |
| // same type |
| |
| template<class T> struct common_type_impl<T, T> |
| { |
| typedef T type; |
| }; |
| |
| // one of the operands is a class type, try conversions in both directions |
| |
| template<class T, class U> struct ct_class |
| { |
| BOOST_STATIC_CONSTANT( bool, ct = boost::is_class<T>::value || boost::is_union<T>::value ); |
| BOOST_STATIC_CONSTANT( bool, cu = boost::is_class<U>::value || boost::is_union<U>::value ); |
| |
| BOOST_STATIC_CONSTANT( bool, value = ct || cu ); |
| }; |
| |
| template<class T, class U> struct common_type_impl3; |
| |
| template<class T, class U> struct common_type_class: public boost::conditional< |
| |
| boost::is_convertible<T, U>::value && !boost::is_convertible<U, T>::value, |
| boost::type_identity<U>, |
| |
| typename boost::conditional< |
| |
| boost::is_convertible<U, T>::value && !boost::is_convertible<T, U>::value, |
| boost::type_identity<T>, |
| |
| common_type_impl3<T, U> |
| >::type |
| >::type |
| { |
| }; |
| |
| template<class T, class U> struct common_type_impl: public boost::conditional< |
| ct_class<T, U>::value, |
| common_type_class<T, U>, |
| common_type_impl3<T, U> >::type |
| { |
| }; |
| |
| // pointers |
| |
| template<class T, class U> struct common_type_impl4; |
| |
| template<class T, class U> struct common_type_impl3: public boost::conditional< |
| boost::is_pointer<T>::value || boost::is_pointer<U>::value, |
| composite_pointer_type<T, U>, |
| common_type_impl4<T, U> >::type |
| { |
| }; |
| |
| // pointers to members |
| |
| template<class T, class U> struct common_type_impl5; |
| |
| template<class T, class U> struct common_type_impl4: public boost::conditional< |
| boost::is_member_pointer<T>::value || boost::is_member_pointer<U>::value, |
| composite_member_pointer_type<T, U>, |
| common_type_impl5<T, U> >::type |
| { |
| }; |
| |
| // arithmetic types (including class types w/ conversions to arithmetic and enums) |
| |
| template<class T, class U> struct common_type_impl5: public common_arithmetic_type<T, U> |
| { |
| }; |
| |
| } // namespace type_traits_detail |
| |
| } // namespace boost |
| |
| #endif // #ifndef BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED |