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111 lines
3.2 KiB
C++
111 lines
3.2 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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#define _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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#include <__config>
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#include <__functional/invoke.h>
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#include <__functional/weak_result_type.h>
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#include <__memory/addressof.h>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/remove_cvref.h>
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#include <__utility/declval.h>
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#include <__utility/forward.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp>
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class _LIBCPP_TEMPLATE_VIS reference_wrapper : public __weak_result_type<_Tp>
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{
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public:
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// types
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typedef _Tp type;
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private:
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type* __f_;
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static void __fun(_Tp&) _NOEXCEPT;
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static void __fun(_Tp&&) = delete;
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public:
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template <class _Up, class = __enable_if_t<!__is_same_uncvref<_Up, reference_wrapper>::value, decltype(__fun(std::declval<_Up>())) > >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper(_Up&& __u) _NOEXCEPT_(noexcept(__fun(std::declval<_Up>()))) {
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type& __f = static_cast<_Up&&>(__u);
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__f_ = _VSTD::addressof(__f);
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}
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// access
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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operator type&() const _NOEXCEPT {return *__f_;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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type& get() const _NOEXCEPT {return *__f_;}
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// invoke
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template <class... _ArgTypes>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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typename __invoke_of<type&, _ArgTypes...>::type
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operator() (_ArgTypes&&... __args) const
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#if _LIBCPP_STD_VER >= 17
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// Since is_nothrow_invocable requires C++17 LWG3764 is not backported
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// to earlier versions.
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noexcept(is_nothrow_invocable_v<_Tp&, _ArgTypes...>)
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#endif
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{
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return std::__invoke(get(), std::forward<_ArgTypes>(__args)...);
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}
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};
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#if _LIBCPP_STD_VER >= 17
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template <class _Tp>
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reference_wrapper(_Tp&) -> reference_wrapper<_Tp>;
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#endif
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<_Tp>
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ref(_Tp& __t) _NOEXCEPT
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{
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return reference_wrapper<_Tp>(__t);
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<_Tp>
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ref(reference_wrapper<_Tp> __t) _NOEXCEPT
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{
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return __t;
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<const _Tp>
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cref(const _Tp& __t) _NOEXCEPT
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{
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return reference_wrapper<const _Tp>(__t);
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<const _Tp>
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cref(reference_wrapper<_Tp> __t) _NOEXCEPT
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{
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return __t;
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}
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template <class _Tp> void ref(const _Tp&&) = delete;
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template <class _Tp> void cref(const _Tp&&) = delete;
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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