xref: /llvm-project/libcxx/include/__iterator/wrap_iter.h (revision 9f471fd12b9e2d6264f27974feaf893445e92393)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___ITERATOR_WRAP_ITER_H
11 #define _LIBCPP___ITERATOR_WRAP_ITER_H
12 
13 #include <__compare/ordering.h>
14 #include <__compare/three_way_comparable.h>
15 #include <__config>
16 #include <__cstddef/size_t.h>
17 #include <__iterator/iterator_traits.h>
18 #include <__memory/addressof.h>
19 #include <__memory/pointer_traits.h>
20 #include <__type_traits/conjunction.h>
21 #include <__type_traits/disjunction.h>
22 #include <__type_traits/enable_if.h>
23 #include <__type_traits/integral_constant.h>
24 #include <__type_traits/is_convertible.h>
25 #include <__type_traits/is_same.h>
26 #include <__type_traits/make_const_lvalue_ref.h>
27 
28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
29 #  pragma GCC system_header
30 #endif
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 template <class _Iter>
35 class __wrap_iter {
36 public:
37   typedef _Iter iterator_type;
38   typedef typename iterator_traits<iterator_type>::value_type value_type;
39   typedef typename iterator_traits<iterator_type>::difference_type difference_type;
40   typedef typename iterator_traits<iterator_type>::pointer pointer;
41   typedef typename iterator_traits<iterator_type>::reference reference;
42   typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
43 #if _LIBCPP_STD_VER >= 20
44   typedef contiguous_iterator_tag iterator_concept;
45 #endif
46 
47 private:
48   iterator_type __i_;
49 
50 public:
51   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter() _NOEXCEPT : __i_() {}
52   template <
53       class _OtherIter,
54       __enable_if_t< _And< is_convertible<const _OtherIter&, _Iter>,
55                            _Or<is_same<reference, __iter_reference<_OtherIter> >,
56                                is_same<reference, __make_const_lvalue_ref<__iter_reference<_OtherIter> > > > >::value,
57                      int> = 0>
58   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter(const __wrap_iter<_OtherIter>& __u) _NOEXCEPT
59       : __i_(__u.__i_) {}
60   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference operator*() const _NOEXCEPT { return *__i_; }
61   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pointer operator->() const _NOEXCEPT {
62     return std::__to_address(__i_);
63   }
64   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter& operator++() _NOEXCEPT {
65     ++__i_;
66     return *this;
67   }
68   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter operator++(int) _NOEXCEPT {
69     __wrap_iter __tmp(*this);
70     ++(*this);
71     return __tmp;
72   }
73 
74   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter& operator--() _NOEXCEPT {
75     --__i_;
76     return *this;
77   }
78   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter operator--(int) _NOEXCEPT {
79     __wrap_iter __tmp(*this);
80     --(*this);
81     return __tmp;
82   }
83   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter operator+(difference_type __n) const _NOEXCEPT {
84     __wrap_iter __w(*this);
85     __w += __n;
86     return __w;
87   }
88   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter& operator+=(difference_type __n) _NOEXCEPT {
89     __i_ += __n;
90     return *this;
91   }
92   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter operator-(difference_type __n) const _NOEXCEPT {
93     return *this + (-__n);
94   }
95   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter& operator-=(difference_type __n) _NOEXCEPT {
96     *this += -__n;
97     return *this;
98   }
99   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference operator[](difference_type __n) const _NOEXCEPT {
100     return __i_[__n];
101   }
102 
103   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 iterator_type base() const _NOEXCEPT { return __i_; }
104 
105 private:
106   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __wrap_iter(iterator_type __x) _NOEXCEPT : __i_(__x) {}
107 
108   template <class _Up>
109   friend class __wrap_iter;
110   template <class _CharT, class _Traits, class _Alloc>
111   friend class basic_string;
112   template <class _CharT, class _Traits>
113   friend class basic_string_view;
114   template <class _Tp, class _Alloc>
115   friend class _LIBCPP_TEMPLATE_VIS vector;
116   template <class _Tp, size_t>
117   friend class _LIBCPP_TEMPLATE_VIS span;
118   template <class _Tp, size_t _Size>
119   friend struct array;
120 };
121 
122 template <class _Iter1>
123 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
124 operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
125   return __x.base() == __y.base();
126 }
127 
128 template <class _Iter1, class _Iter2>
129 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
130 operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
131   return __x.base() == __y.base();
132 }
133 
134 template <class _Iter1>
135 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
136 operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
137   return __x.base() < __y.base();
138 }
139 
140 template <class _Iter1, class _Iter2>
141 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
142 operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
143   return __x.base() < __y.base();
144 }
145 
146 #if _LIBCPP_STD_VER <= 17
147 template <class _Iter1>
148 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
149 operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
150   return !(__x == __y);
151 }
152 
153 template <class _Iter1, class _Iter2>
154 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
155 operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
156   return !(__x == __y);
157 }
158 template <class _Iter1>
159 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
160 operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
161   return __y < __x;
162 }
163 
164 template <class _Iter1, class _Iter2>
165 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
166 operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
167   return __y < __x;
168 }
169 
170 template <class _Iter1>
171 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
172 operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
173   return !(__x < __y);
174 }
175 
176 template <class _Iter1, class _Iter2>
177 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
178 operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
179   return !(__x < __y);
180 }
181 
182 template <class _Iter1>
183 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
184 operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT {
185   return !(__y < __x);
186 }
187 
188 template <class _Iter1, class _Iter2>
189 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
190 operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT {
191   return !(__y < __x);
192 }
193 
194 #else
195 template <class _Iter1, class _Iter2>
196 _LIBCPP_HIDE_FROM_ABI constexpr strong_ordering
197 operator<=>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) noexcept {
198   if constexpr (three_way_comparable_with<_Iter1, _Iter2, strong_ordering>) {
199     return __x.base() <=> __y.base();
200   } else {
201     if (__x.base() < __y.base())
202       return strong_ordering::less;
203 
204     if (__x.base() == __y.base())
205       return strong_ordering::equal;
206 
207     return strong_ordering::greater;
208   }
209 }
210 #endif // _LIBCPP_STD_VER >= 20
211 
212 template <class _Iter1, class _Iter2>
213 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
214 #ifndef _LIBCPP_CXX03_LANG
215     auto
216     operator-(const __wrap_iter<_Iter1>& __x,
217               const __wrap_iter<_Iter2>& __y) _NOEXCEPT->decltype(__x.base() - __y.base())
218 #else
219 typename __wrap_iter<_Iter1>::difference_type
220 operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
221 #endif // C++03
222 {
223   return __x.base() - __y.base();
224 }
225 
226 template <class _Iter1>
227 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter<_Iter1>
228 operator+(typename __wrap_iter<_Iter1>::difference_type __n, __wrap_iter<_Iter1> __x) _NOEXCEPT {
229   __x += __n;
230   return __x;
231 }
232 
233 #if _LIBCPP_STD_VER <= 17
234 template <class _It>
235 struct __libcpp_is_contiguous_iterator<__wrap_iter<_It> > : true_type {};
236 #endif
237 
238 template <class _It>
239 struct _LIBCPP_TEMPLATE_VIS pointer_traits<__wrap_iter<_It> > {
240   typedef __wrap_iter<_It> pointer;
241   typedef typename pointer_traits<_It>::element_type element_type;
242   typedef typename pointer_traits<_It>::difference_type difference_type;
243 
244   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static element_type* to_address(pointer __w) _NOEXCEPT {
245     return std::__to_address(__w.base());
246   }
247 };
248 
249 _LIBCPP_END_NAMESPACE_STD
250 
251 #endif // _LIBCPP___ITERATOR_WRAP_ITER_H
252