183 lines
5.2 KiB
C++
183 lines
5.2 KiB
C++
// Pointer Traits -*- C++ -*-
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// Copyright (C) 2011-2012 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file bits/ptr_traits.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{memory}
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*/
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#ifndef _PTR_TRAITS_H
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#define _PTR_TRAITS_H 1
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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#include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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_GLIBCXX_HAS_NESTED_TYPE(element_type)
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_GLIBCXX_HAS_NESTED_TYPE(difference_type)
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template<typename _Tp, bool = __has_element_type<_Tp>::value>
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struct __ptrtr_elt_type;
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template<typename _Tp>
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struct __ptrtr_elt_type<_Tp, true>
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{
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typedef typename _Tp::element_type __type;
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};
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template<template<typename, typename...> class _SomePtr, typename _Tp,
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typename... _Args>
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struct __ptrtr_elt_type<_SomePtr<_Tp, _Args...>, false>
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{
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typedef _Tp __type;
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};
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template<typename _Tp, bool = __has_difference_type<_Tp>::value>
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struct __ptrtr_diff_type
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{
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typedef typename _Tp::difference_type __type;
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};
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template<typename _Tp>
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struct __ptrtr_diff_type<_Tp, false>
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{
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typedef ptrdiff_t __type;
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};
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template<typename _Ptr, typename _Up>
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class __ptrtr_rebind_helper
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{
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template<typename _Ptr2, typename _Up2>
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static constexpr bool
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_S_chk(typename _Ptr2::template rebind<_Up2>*)
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{ return true; }
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template<typename, typename>
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static constexpr bool
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_S_chk(...)
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{ return false; }
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public:
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static const bool __value = _S_chk<_Ptr, _Up>(nullptr);
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};
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template<typename _Ptr, typename _Up>
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const bool __ptrtr_rebind_helper<_Ptr, _Up>::__value;
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template<typename _Tp, typename _Up,
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bool = __ptrtr_rebind_helper<_Tp, _Up>::__value>
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struct __ptrtr_rebind;
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template<typename _Tp, typename _Up>
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struct __ptrtr_rebind<_Tp, _Up, true>
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{
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typedef typename _Tp::template rebind<_Up> __type;
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};
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template<template<typename, typename...> class _SomePtr, typename _Up,
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typename _Tp, typename... _Args>
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struct __ptrtr_rebind<_SomePtr<_Tp, _Args...>, _Up, false>
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{
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typedef _SomePtr<_Up, _Args...> __type;
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};
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template<typename _Tp, typename = typename remove_cv<_Tp>::type>
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struct __ptrtr_not_void
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{
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typedef _Tp __type;
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};
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template<typename _Tp>
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struct __ptrtr_not_void<_Tp, void>
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{
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struct __type { };
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};
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template<typename _Ptr>
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class __ptrtr_pointer_to
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{
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typedef typename __ptrtr_elt_type<_Ptr>::__type __orig_type;
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typedef typename __ptrtr_not_void<__orig_type>::__type __element_type;
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public:
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static _Ptr pointer_to(__element_type& __e)
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{ return _Ptr::pointer_to(__e); }
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};
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/**
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* @brief Uniform interface to all pointer-like types
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* @ingroup pointer_abstractions
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*/
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template<typename _Ptr>
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struct pointer_traits : __ptrtr_pointer_to<_Ptr>
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{
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/// The pointer type
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typedef _Ptr pointer;
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/// The type pointed to
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typedef typename __ptrtr_elt_type<_Ptr>::__type element_type;
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/// Type used to represent the difference between two pointers
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typedef typename __ptrtr_diff_type<_Ptr>::__type difference_type;
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template<typename _Up>
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using rebind = typename __ptrtr_rebind<_Ptr, _Up>::__type;
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};
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/**
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* @brief Partial specialization for built-in pointers.
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* @ingroup pointer_abstractions
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*/
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template<typename _Tp>
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struct pointer_traits<_Tp*>
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{
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/// The pointer type
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typedef _Tp* pointer;
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/// The type pointed to
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typedef _Tp element_type;
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/// Type used to represent the difference between two pointers
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typedef ptrdiff_t difference_type;
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template<typename _Up>
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using rebind = _Up*;
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/**
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* @brief Obtain a pointer to an object
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* @param __r A reference to an object of type @c element_type
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* @return @c addressof(__r)
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*/
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static pointer
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pointer_to(typename __ptrtr_not_void<element_type>::__type& __r) noexcept
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{ return std::addressof(__r); }
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};
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif
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#endif
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