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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
#define _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
#include <__compare/synth_three_way.h>
#include <__concepts/boolean_testable.h>
#include <__config>
#include <__functional/invoke.h>
#include <__functional/weak_result_type.h>
#include <__memory/addressof.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_const.h>
#include <__type_traits/remove_cvref.h>
#include <__type_traits/void_t.h>
#include <__utility/declval.h>
#include <__utility/forward.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp>
class _LIBCPP_TEMPLATE_VIS reference_wrapper : public __weak_result_type<_Tp> {
public:
// types
typedef _Tp type;
private:
type* __f_;
static void __fun(_Tp&) _NOEXCEPT;
static void __fun(_Tp&&) = delete; // NOLINT(modernize-use-equals-delete) ; This is llvm.org/PR54276
public:
template <class _Up,
class = __void_t<decltype(__fun(std::declval<_Up>()))>,
__enable_if_t<!__is_same_uncvref<_Up, reference_wrapper>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper(_Up&& __u)
_NOEXCEPT_(noexcept(__fun(std::declval<_Up>()))) {
type& __f = static_cast<_Up&&>(__u);
__f_ = std::addressof(__f);
}
// access
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 operator type&() const _NOEXCEPT { return *__f_; }
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 type& get() const _NOEXCEPT { return *__f_; }
// invoke
template <class... _ArgTypes>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename __invoke_of<type&, _ArgTypes...>::type
operator()(_ArgTypes&&... __args) const
#if _LIBCPP_STD_VER >= 17
// Since is_nothrow_invocable requires C++17 LWG3764 is not backported
// to earlier versions.
noexcept(is_nothrow_invocable_v<_Tp&, _ArgTypes...>)
#endif
{
return std::__invoke(get(), std::forward<_ArgTypes>(__args)...);
}
#if _LIBCPP_STD_VER >= 26
// [refwrap.comparisons], comparisons
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(reference_wrapper __x, reference_wrapper __y)
requires requires {
{ __x.get() == __y.get() } -> __boolean_testable;
}
{
return __x.get() == __y.get();
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(reference_wrapper __x, const _Tp& __y)
requires requires {
{ __x.get() == __y } -> __boolean_testable;
}
{
return __x.get() == __y;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(reference_wrapper __x, reference_wrapper<const _Tp> __y)
requires(!is_const_v<_Tp>) && requires {
{ __x.get() == __y.get() } -> __boolean_testable;
}
{
return __x.get() == __y.get();
}
_LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(reference_wrapper __x, reference_wrapper __y)
requires requires { std::__synth_three_way(__x.get(), __y.get()); }
{
return std::__synth_three_way(__x.get(), __y.get());
}
_LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(reference_wrapper __x, const _Tp& __y)
requires requires { std::__synth_three_way(__x.get(), __y); }
{
return std::__synth_three_way(__x.get(), __y);
}
_LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(reference_wrapper __x, reference_wrapper<const _Tp> __y)
requires(!is_const_v<_Tp>) && requires { std::__synth_three_way(__x.get(), __y.get()); }
{
return std::__synth_three_way(__x.get(), __y.get());
}
#endif // _LIBCPP_STD_VER >= 26
};
#if _LIBCPP_STD_VER >= 17
template <class _Tp>
reference_wrapper(_Tp&) -> reference_wrapper<_Tp>;
#endif
template <class _Tp>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper<_Tp> ref(_Tp& __t) _NOEXCEPT {
return reference_wrapper<_Tp>(__t);
}
template <class _Tp>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper<_Tp>
ref(reference_wrapper<_Tp> __t) _NOEXCEPT {
return __t;
}
template <class _Tp>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper<const _Tp> cref(const _Tp& __t) _NOEXCEPT {
return reference_wrapper<const _Tp>(__t);
}
template <class _Tp>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper<const _Tp>
cref(reference_wrapper<_Tp> __t) _NOEXCEPT {
return __t;
}
template <class _Tp>
void ref(const _Tp&&) = delete;
template <class _Tp>
void cref(const _Tp&&) = delete;
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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