154 lines
3.7 KiB
Plaintext
154 lines
3.7 KiB
Plaintext
#ifndef BOOST_TYPE_TRAITS_DETAIL_COMPOSITE_POINTER_TYPE_HPP_INCLUDED
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#define BOOST_TYPE_TRAITS_DETAIL_COMPOSITE_POINTER_TYPE_HPP_INCLUDED
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//
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// Copyright 2015 Peter Dimov
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//
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// Distributed under the Boost Software License, Version 1.0.
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#include <boost/type_traits/copy_cv.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_traits/is_void.hpp>
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#include <boost/type_traits/is_base_of.hpp>
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#include <boost/config.hpp>
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#include <cstddef>
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namespace boost
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{
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namespace type_traits_detail
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{
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template<class T, class U> struct composite_pointer_type;
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// same type
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template<class T> struct composite_pointer_type<T*, T*>
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{
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typedef T* type;
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};
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// nullptr_t
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#if !defined( BOOST_NO_CXX11_NULLPTR )
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#if !defined( BOOST_NO_CXX11_DECLTYPE ) && ( ( defined( __clang__ ) && !defined( _LIBCPP_VERSION ) ) || defined( __INTEL_COMPILER ) )
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template<class T> struct composite_pointer_type<T*, decltype(nullptr)>
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{
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typedef T* type;
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};
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template<class T> struct composite_pointer_type<decltype(nullptr), T*>
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{
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typedef T* type;
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};
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template<> struct composite_pointer_type<decltype(nullptr), decltype(nullptr)>
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{
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typedef decltype(nullptr) type;
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};
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#else
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template<class T> struct composite_pointer_type<T*, std::nullptr_t>
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{
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typedef T* type;
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};
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template<class T> struct composite_pointer_type<std::nullptr_t, T*>
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{
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typedef T* type;
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};
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template<> struct composite_pointer_type<std::nullptr_t, std::nullptr_t>
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{
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typedef std::nullptr_t type;
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};
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#endif
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#endif // !defined( BOOST_NO_CXX11_NULLPTR )
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namespace detail
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{
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template<class T, class U> struct has_common_pointee
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{
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private:
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typedef typename boost::remove_cv<T>::type T2;
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typedef typename boost::remove_cv<U>::type U2;
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public:
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BOOST_STATIC_CONSTANT( bool, value =
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(boost::is_same<T2, U2>::value)
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|| boost::is_void<T2>::value
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|| boost::is_void<U2>::value
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|| (boost::is_base_of<T2, U2>::value)
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|| (boost::is_base_of<U2, T2>::value) );
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};
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template<class T, class U> struct common_pointee
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{
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private:
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typedef typename boost::remove_cv<T>::type T2;
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typedef typename boost::remove_cv<U>::type U2;
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public:
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typedef typename boost::conditional<
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boost::is_same<T2, U2>::value || boost::is_void<T2>::value || boost::is_base_of<T2, U2>::value,
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typename boost::copy_cv<T, U>::type,
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typename boost::copy_cv<U, T>::type
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>::type type;
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};
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template<class T, class U> struct composite_pointer_impl
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{
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private:
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typedef typename boost::remove_cv<T>::type T2;
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typedef typename boost::remove_cv<U>::type U2;
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public:
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typedef typename boost::copy_cv<typename boost::copy_cv<typename composite_pointer_type<T2, U2>::type const, T>::type, U>::type type;
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};
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//Old compilers like MSVC-7.1 have problems using boost::conditional in
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//composite_pointer_type. Partially specializing on has_common_pointee<T, U>::value
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//seems to make their life easier
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template<class T, class U, bool = has_common_pointee<T, U>::value >
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struct composite_pointer_type_dispatch
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: common_pointee<T, U>
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{};
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template<class T, class U>
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struct composite_pointer_type_dispatch<T, U, false>
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: composite_pointer_impl<T, U>
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{};
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} // detail
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template<class T, class U> struct composite_pointer_type<T*, U*>
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{
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typedef typename detail::composite_pointer_type_dispatch<T, U>::type* type;
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};
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} // namespace type_traits_detail
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} // namespace boost
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#endif // #ifndef BOOST_TYPE_TRAITS_DETAIL_COMPOSITE_POINTER_TYPE_HPP_INCLUDED
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