CoCalc -- pointer

GitHub Repository: freebsd/freebsd-src
Path: blob/main/contrib/llvm-project/libcxx/include/__memory/pointer_traits.h
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// -*- 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___MEMORY_POINTER_TRAITS_H
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#define _LIBCPP___MEMORY_POINTER_TRAITS_H
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#include <__config>
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#include <__memory/addressof.h>
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#include <__type_traits/conditional.h>
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#include <__type_traits/conjunction.h>
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#include <__type_traits/decay.h>
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#include <__type_traits/is_class.h>
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#include <__type_traits/is_function.h>
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#include <__type_traits/is_void.h>
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#include <__type_traits/void_t.h>
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#include <__utility/declval.h>
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#include <__utility/forward.h>
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#include <cstddef>
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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_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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// clang-format off
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#define _LIBCPP_CLASS_TRAITS_HAS_XXX(NAME, PROPERTY)                                                                   \
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  template <class _Tp, class = void>                                                                                   \
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  struct NAME : false_type {};                                                                                         \
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  template <class _Tp>                                                                                                 \
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  struct NAME<_Tp, __void_t<typename _Tp::PROPERTY> > : true_type {}
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// clang-format on
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_LIBCPP_CLASS_TRAITS_HAS_XXX(__has_pointer, pointer);
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_LIBCPP_CLASS_TRAITS_HAS_XXX(__has_element_type, element_type);
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template <class _Ptr, bool = __has_element_type<_Ptr>::value>
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struct __pointer_traits_element_type {};
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template <class _Ptr>
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struct __pointer_traits_element_type<_Ptr, true> {
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  typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class... _Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true> {
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  typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class... _Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false> {
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  typedef _LIBCPP_NODEBUG _Tp type;
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};
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template <class _Tp, class = void>
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struct __has_difference_type : false_type {};
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template <class _Tp>
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struct __has_difference_type<_Tp, __void_t<typename _Tp::difference_type> > : true_type {};
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template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
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struct __pointer_traits_difference_type {
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  typedef _LIBCPP_NODEBUG ptrdiff_t type;
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};
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template <class _Ptr>
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struct __pointer_traits_difference_type<_Ptr, true> {
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  typedef _LIBCPP_NODEBUG typename _Ptr::difference_type type;
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};
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template <class _Tp, class _Up>
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struct __has_rebind {
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private:
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  template <class _Xp>
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  static false_type __test(...);
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  _LIBCPP_SUPPRESS_DEPRECATED_PUSH
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  template <class _Xp>
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  static true_type __test(typename _Xp::template rebind<_Up>* = 0);
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  _LIBCPP_SUPPRESS_DEPRECATED_POP
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public:
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  static const bool value = decltype(__test<_Tp>(0))::value;
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};
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template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
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struct __pointer_traits_rebind {
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#ifndef _LIBCPP_CXX03_LANG
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  typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up> type;
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#else
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  typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class... _Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true> {
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#ifndef _LIBCPP_CXX03_LANG
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  typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
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#else
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  typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class... _Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false> {
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  typedef _Sp<_Up, _Args...> type;
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};
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template <class _Ptr, class = void>
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struct __pointer_traits_impl {};
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template <class _Ptr>
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struct __pointer_traits_impl<_Ptr, __void_t<typename __pointer_traits_element_type<_Ptr>::type> > {
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  typedef _Ptr pointer;
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  typedef typename __pointer_traits_element_type<pointer>::type element_type;
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  typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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  template <class _Up>
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  using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
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#else
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  template <class _Up>
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  struct rebind {
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    typedef typename __pointer_traits_rebind<pointer, _Up>::type other;
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  };
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#endif // _LIBCPP_CXX03_LANG
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private:
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  struct __nat {};
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public:
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  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
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  pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r) {
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    return pointer::pointer_to(__r);
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  }
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};
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template <class _Ptr>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits : __pointer_traits_impl<_Ptr> {};
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*> {
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  typedef _Tp* pointer;
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  typedef _Tp element_type;
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  typedef ptrdiff_t difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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  template <class _Up>
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  using rebind = _Up*;
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#else
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  template <class _Up>
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  struct rebind {
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    typedef _Up* other;
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  };
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#endif
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private:
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  struct __nat {};
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public:
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  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
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  pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r) _NOEXCEPT {
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    return std::addressof(__r);
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  }
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};
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#ifndef _LIBCPP_CXX03_LANG
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template <class _From, class _To>
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using __rebind_pointer_t = typename pointer_traits<_From>::template rebind<_To>;
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#else
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template <class _From, class _To>
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using __rebind_pointer_t = typename pointer_traits<_From>::template rebind<_To>::other;
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#endif
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// to_address
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template <class _Pointer, class = void>
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struct __to_address_helper;
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template <class _Tp>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp* __to_address(_Tp* __p) _NOEXCEPT {
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  static_assert(!is_function<_Tp>::value, "_Tp is a function type");
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  return __p;
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}
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template <class _Pointer, class = void>
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struct _HasToAddress : false_type {};
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template <class _Pointer>
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struct _HasToAddress<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>())) >
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    : true_type {};
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template <class _Pointer, class = void>
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struct _HasArrow : false_type {};
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template <class _Pointer>
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struct _HasArrow<_Pointer, decltype((void)std::declval<const _Pointer&>().operator->()) > : true_type {};
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template <class _Pointer>
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struct _IsFancyPointer {
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  static const bool value = _HasArrow<_Pointer>::value || _HasToAddress<_Pointer>::value;
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};
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// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
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template <class _Pointer, __enable_if_t< _And<is_class<_Pointer>, _IsFancyPointer<_Pointer> >::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI
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_LIBCPP_CONSTEXPR __decay_t<decltype(__to_address_helper<_Pointer>::__call(std::declval<const _Pointer&>()))>
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__to_address(const _Pointer& __p) _NOEXCEPT {
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  return __to_address_helper<_Pointer>::__call(__p);
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}
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template <class _Pointer, class>
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struct __to_address_helper {
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  _LIBCPP_HIDE_FROM_ABI
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  _LIBCPP_CONSTEXPR static decltype(std::__to_address(std::declval<const _Pointer&>().operator->()))
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  __call(const _Pointer& __p) _NOEXCEPT {
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    return std::__to_address(__p.operator->());
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  }
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};
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template <class _Pointer>
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struct __to_address_helper<_Pointer,
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                           decltype((void)pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>()))> {
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  _LIBCPP_HIDE_FROM_ABI
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  _LIBCPP_CONSTEXPR static decltype(pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>()))
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  __call(const _Pointer& __p) _NOEXCEPT {
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    return pointer_traits<_Pointer>::to_address(__p);
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  }
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};
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#if _LIBCPP_STD_VER >= 20
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template <class _Tp>
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inline _LIBCPP_HIDE_FROM_ABI constexpr auto to_address(_Tp* __p) noexcept {
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  return std::__to_address(__p);
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}
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template <class _Pointer>
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inline _LIBCPP_HIDE_FROM_ABI constexpr auto
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to_address(const _Pointer& __p) noexcept -> decltype(std::__to_address(__p)) {
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  return std::__to_address(__p);
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}
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#endif
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#if _LIBCPP_STD_VER >= 23
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template <class _Tp>
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struct __pointer_of {};
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template <class _Tp>
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  requires(__has_pointer<_Tp>::value)
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struct __pointer_of<_Tp> {
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  using type = typename _Tp::pointer;
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};
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template <class _Tp>
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  requires(!__has_pointer<_Tp>::value && __has_element_type<_Tp>::value)
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struct __pointer_of<_Tp> {
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  using type = typename _Tp::element_type*;
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};
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template <class _Tp>
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  requires(!__has_pointer<_Tp>::value && !__has_element_type<_Tp>::value &&
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           __has_element_type<pointer_traits<_Tp>>::value)
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struct __pointer_of<_Tp> {
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  using type = typename pointer_traits<_Tp>::element_type*;
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};
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template <typename _Tp>
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using __pointer_of_t = typename __pointer_of<_Tp>::type;
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template <class _Tp, class _Up>
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struct __pointer_of_or {
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  using type _LIBCPP_NODEBUG = _Up;
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};
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template <class _Tp, class _Up>
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  requires requires { typename __pointer_of_t<_Tp>; }
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struct __pointer_of_or<_Tp, _Up> {
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  using type _LIBCPP_NODEBUG = __pointer_of_t<_Tp>;
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};
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template <typename _Tp, typename _Up>
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using __pointer_of_or_t = typename __pointer_of_or<_Tp, _Up>::type;
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template <class _Smart>
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concept __resettable_smart_pointer = requires(_Smart __s) { __s.reset(); };
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template <class _Smart, class _Pointer, class... _Args>
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concept __resettable_smart_pointer_with_args = requires(_Smart __s, _Pointer __p, _Args... __args) {
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  __s.reset(static_cast<__pointer_of_or_t<_Smart, _Pointer>>(__p), std::forward<_Args>(__args)...);
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};
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#endif
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H
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