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|---|---|---|
| 7c673cae FG |
1 | #ifndef BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED |
| 2 | #define BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED | |
| 3 | ||
| 4 | // | |
| 5 | // Copyright 2015 Peter Dimov | |
| 6 | // | |
| 7 | // Distributed under the Boost Software License, Version 1.0. | |
| 8 | // See accompanying file LICENSE_1_0.txt or copy at | |
| 9 | // http://www.boost.org/LICENSE_1_0.txt | |
| 10 | // | |
| 11 | ||
| 12 | #include <boost/type_traits/detail/common_arithmetic_type.hpp> | |
| 13 | #include <boost/type_traits/detail/composite_pointer_type.hpp> | |
| 14 | #include <boost/type_traits/detail/composite_member_pointer_type.hpp> | |
| 15 | #include <boost/type_traits/type_identity.hpp> | |
| 16 | #include <boost/type_traits/is_class.hpp> | |
| 17 | #include <boost/type_traits/is_union.hpp> | |
| 18 | #include <boost/type_traits/is_convertible.hpp> | |
| 19 | #include <boost/type_traits/is_pointer.hpp> | |
| 20 | #include <boost/type_traits/is_member_pointer.hpp> | |
| 21 | #include <boost/type_traits/conditional.hpp> | |
| 22 | ||
| 23 | namespace boost | |
| 24 | { | |
| 25 | ||
| 26 | namespace type_traits_detail | |
| 27 | { | |
| 28 | ||
| 29 | // the arguments to common_type_impl have already been passed through decay<> | |
| 30 | ||
| 31 | template<class T, class U> struct common_type_impl; | |
| 32 | ||
| 33 | // same type | |
| 34 | ||
| 35 | template<class T> struct common_type_impl<T, T> | |
| 36 | { | |
| 37 | typedef T type; | |
| 38 | }; | |
| 39 | ||
| 40 | // one of the operands is a class type, try conversions in both directions | |
| 41 | ||
| 42 | template<class T, class U> struct ct_class | |
| 43 | { | |
| 44 | BOOST_STATIC_CONSTANT( bool, ct = boost::is_class<T>::value || boost::is_union<T>::value ); | |
| 45 | BOOST_STATIC_CONSTANT( bool, cu = boost::is_class<U>::value || boost::is_union<U>::value ); | |
| 46 | ||
| 47 | BOOST_STATIC_CONSTANT( bool, value = ct || cu ); | |
| 48 | }; | |
| 49 | ||
| 50 | template<class T, class U> struct common_type_impl3; | |
| 51 | ||
| 52 | template<class T, class U> struct common_type_class: public boost::conditional< | |
| 53 | ||
| 54 | boost::is_convertible<T, U>::value && !boost::is_convertible<U, T>::value, | |
| 55 | boost::type_identity<U>, | |
| 56 | ||
| 57 | typename boost::conditional< | |
| 58 | ||
| 59 | boost::is_convertible<U, T>::value && !boost::is_convertible<T, U>::value, | |
| 60 | boost::type_identity<T>, | |
| 61 | ||
| 62 | common_type_impl3<T, U> | |
| 63 | >::type | |
| 64 | >::type | |
| 65 | { | |
| 66 | }; | |
| 67 | ||
| 68 | template<class T, class U> struct common_type_impl: public boost::conditional< | |
| 69 | ct_class<T, U>::value, | |
| 70 | common_type_class<T, U>, | |
| 71 | common_type_impl3<T, U> >::type | |
| 72 | { | |
| 73 | }; | |
| 74 | ||
| 75 | // pointers | |
| 76 | ||
| 77 | template<class T, class U> struct common_type_impl4; | |
| 78 | ||
| 79 | template<class T, class U> struct common_type_impl3: public boost::conditional< | |
| 80 | boost::is_pointer<T>::value || boost::is_pointer<U>::value, | |
| 81 | composite_pointer_type<T, U>, | |
| 82 | common_type_impl4<T, U> >::type | |
| 83 | { | |
| 84 | }; | |
| 85 | ||
| 86 | // pointers to members | |
| 87 | ||
| 88 | template<class T, class U> struct common_type_impl5; | |
| 89 | ||
| 90 | template<class T, class U> struct common_type_impl4: public boost::conditional< | |
| 91 | boost::is_member_pointer<T>::value || boost::is_member_pointer<U>::value, | |
| 92 | composite_member_pointer_type<T, U>, | |
| 93 | common_type_impl5<T, U> >::type | |
| 94 | { | |
| 95 | }; | |
| 96 | ||
| 97 | // arithmetic types (including class types w/ conversions to arithmetic and enums) | |
| 98 | ||
| 99 | template<class T, class U> struct common_type_impl5: public common_arithmetic_type<T, U> | |
| 100 | { | |
| 101 | }; | |
| 102 | ||
| 103 | } // namespace type_traits_detail | |
| 104 | ||
| 105 | } // namespace boost | |
| 106 | ||
| 107 | #endif // #ifndef BOOST_TYPE_TRAITS_DETAIL_COMMON_TYPE_IMPL_HPP_INCLUDED |