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Diffstat (limited to 'boost/type_traits/is_copy_assignable.hpp')
| -rw-r--r-- | boost/type_traits/is_copy_assignable.hpp | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/boost/type_traits/is_copy_assignable.hpp b/boost/type_traits/is_copy_assignable.hpp new file mode 100644 index 0000000000..48af818849 --- /dev/null +++ b/boost/type_traits/is_copy_assignable.hpp @@ -0,0 +1,147 @@ +// (C) Copyright Ion Gaztanaga 2014. +// +// Use, modification and distribution are subject to 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). +// +// See http://www.boost.org/libs/type_traits for most recent version including documentation. + +#ifndef BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED +#define BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED + +#include <boost/config.hpp> +#include <boost/type_traits/detail/yes_no_type.hpp> +#include <boost/type_traits/is_base_and_derived.hpp> +#include <boost/noncopyable.hpp> + +#if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_NO_CXX11_DECLTYPE) \ + && !defined(BOOST_INTEL_CXX_VERSION) && \ + !(defined(BOOST_MSVC) && _MSC_VER == 1800) +#define BOOST_TT_CXX11_IS_COPY_ASSIGNABLE +#include <boost/utility/declval.hpp> +#else + //For compilers without decltype + #include <boost/type_traits/is_const.hpp> + #include <boost/type_traits/is_array.hpp> + #include <boost/type_traits/add_reference.hpp> + #include <boost/type_traits/remove_reference.hpp> +#endif + + +// should be the last #include +#include <boost/type_traits/detail/bool_trait_def.hpp> + +namespace boost { + +namespace detail{ + +template <bool DerivedFromNoncopyable, class T> +struct is_copy_assignable_impl2 { + +// Intel compiler has problems with SFINAE for copy constructors and deleted functions: +// +// error: function *function_name* cannot be referenced -- it is a deleted function +// static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0); +// ^ +// +// MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See: +// https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken +#if defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) + typedef boost::type_traits::yes_type yes_type; + typedef boost::type_traits::no_type no_type; + + template <class U> + static decltype(::boost::declval<U&>() = ::boost::declval<const U&>(), yes_type() ) test(int); + + template <class> + static no_type test(...); + + static const bool value = sizeof(test<T>(0)) == sizeof(yes_type); + +#else + static BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type produce(); + + template <class T1> + static boost::type_traits::no_type test(T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0); + + static boost::type_traits::yes_type test(...); + // If you see errors like this: + // + // `'T::operator=(const T&)' is private` + // `boost/type_traits/is_copy_assignable.hpp:NN:M: error: within this context` + // + // then you are trying to call that macro for a structure defined like that: + // + // struct T { + // ... + // private: + // T & operator=(const T &); + // ... + // }; + // + // To fix that you must modify your structure: + // + // // C++03 and C++11 version + // struct T: private boost::noncopyable { + // ... + // private: + // T & operator=(const T &); + // ... + // }; + // + // // C++11 version + // struct T { + // ... + // private: + // T& operator=(const T &) = delete; + // ... + // }; + BOOST_STATIC_CONSTANT(bool, value = ( + sizeof(test(produce())) == sizeof(boost::type_traits::yes_type) + )); + #endif +}; + +template <class T> +struct is_copy_assignable_impl2<true, T> { + BOOST_STATIC_CONSTANT(bool, value = false); +}; + +template <class T> +struct is_copy_assignable_impl { + +#if !defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) + //For compilers without decltype, at least return false on const types, arrays + //types derived from boost::noncopyable and types defined as BOOST_MOVEABLE_BUT_NOT_COPYABLE + typedef BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type unreferenced_t; + BOOST_STATIC_CONSTANT(bool, value = ( + boost::detail::is_copy_assignable_impl2< + boost::is_base_and_derived<boost::noncopyable, T>::value + || boost::is_const<unreferenced_t>::value || boost::is_array<unreferenced_t>::value + ,T + >::value + )); + #else + BOOST_STATIC_CONSTANT(bool, value = ( + boost::detail::is_copy_assignable_impl2< + boost::is_base_and_derived<boost::noncopyable, T>::value,T + >::value + )); + #endif +}; + +} // namespace detail + +BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_copy_assignable,T,::boost::detail::is_copy_assignable_impl<T>::value) +BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_copy_assignable,void,false) +#ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS +BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_copy_assignable,void const,false) +BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_copy_assignable,void const volatile,false) +BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_copy_assignable,void volatile,false) +#endif + +} // namespace boost + +#include <boost/type_traits/detail/bool_trait_undef.hpp> + +#endif // BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |