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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___FLAT_MAP_KEY_VALUE_ITERATOR_H
11#define _LIBCPP___FLAT_MAP_KEY_VALUE_ITERATOR_H
12
13#include <__compare/three_way_comparable.h>
14#include <__concepts/convertible_to.h>
15#include <__config>
16#include <__cstddef/size_t.h>
17#include <__iterator/iterator_traits.h>
18#include <__iterator/product_iterator.h>
19#include <__memory/addressof.h>
20#include <__type_traits/conditional.h>
21#include <__utility/forward.h>
22#include <__utility/move.h>
23#include <__utility/pair.h>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32#if _LIBCPP_STD_VER >= 23
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36/**
37 * __key_value_iterator is a proxy iterator which zips the underlying
38 * _KeyContainer::iterator and the underlying _MappedContainer::iterator.
39 * The two underlying iterators will be incremented/decremented together.
40 * And the reference is a pair of the const key reference and the value reference.
41 */
42template <class _Owner, class _KeyContainer, class _MappedContainer, bool _Const>
43struct __key_value_iterator {
44private:
45 using __key_iterator _LIBCPP_NODEBUG = typename _KeyContainer::const_iterator;
46 using __mapped_iterator _LIBCPP_NODEBUG =
47 _If<_Const, typename _MappedContainer::const_iterator, typename _MappedContainer::iterator>;
48 using __reference _LIBCPP_NODEBUG = _If<_Const, typename _Owner::const_reference, typename _Owner::reference>;
49
50 struct __arrow_proxy {
51 __reference __ref_;
52 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __reference* operator->() { return std::addressof(__ref_); }
53 };
54
55 __key_iterator __key_iter_;
56 __mapped_iterator __mapped_iter_;
57
58 friend _Owner;
59
60 template <class, class, class, bool>
61 friend struct __key_value_iterator;
62
63 friend struct __product_iterator_traits<__key_value_iterator>;
64
65public:
66 using iterator_concept = random_access_iterator_tag;
67 // `__key_value_iterator` only satisfy "Cpp17InputIterator" named requirements, because
68 // its `reference` is not a reference type.
69 // However, to avoid surprising runtime behaviour when it is used with the
70 // Cpp17 algorithms or operations, iterator_category is set to random_access_iterator_tag.
71 using iterator_category = random_access_iterator_tag;
72 using value_type = typename _Owner::value_type;
73 using difference_type = typename _Owner::difference_type;
74
75 _LIBCPP_HIDE_FROM_ABI __key_value_iterator() = default;
76
77 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26
78 __key_value_iterator(__key_value_iterator<_Owner, _KeyContainer, _MappedContainer, !_Const> __i)
79 requires _Const && convertible_to<typename _KeyContainer::iterator, __key_iterator> &&
80 convertible_to<typename _MappedContainer::iterator, __mapped_iterator>
81 : __key_iter_(std::move(__i.__key_iter_)), __mapped_iter_(std::move(__i.__mapped_iter_)) {}
82
83 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26
84 __key_value_iterator(__key_iterator __key_iter, __mapped_iterator __mapped_iter)
85 : __key_iter_(std::move(__key_iter)), __mapped_iter_(std::move(__mapped_iter)) {}
86
87 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __reference operator*() const {
88 return __reference(*__key_iter_, *__mapped_iter_);
89 }
90 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __arrow_proxy operator->() const { return __arrow_proxy{**this}; }
91
92 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator& operator++() {
93 ++__key_iter_;
94 ++__mapped_iter_;
95 return *this;
96 }
97
98 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator operator++(int) {
99 __key_value_iterator __tmp(*this);
100 ++*this;
101 return __tmp;
102 }
103
104 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator& operator--() {
105 --__key_iter_;
106 --__mapped_iter_;
107 return *this;
108 }
109
110 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator operator--(int) {
111 __key_value_iterator __tmp(*this);
112 --*this;
113 return __tmp;
114 }
115
116 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator& operator+=(difference_type __x) {
117 __key_iter_ += __x;
118 __mapped_iter_ += __x;
119 return *this;
120 }
121
122 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __key_value_iterator& operator-=(difference_type __x) {
123 __key_iter_ -= __x;
124 __mapped_iter_ -= __x;
125 return *this;
126 }
127
128 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __reference operator[](difference_type __n) const {
129 return *(*this + __n);
130 }
131
132 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend bool
133 operator==(const __key_value_iterator& __x, const __key_value_iterator& __y) {
134 return __x.__key_iter_ == __y.__key_iter_;
135 }
136
137 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend bool
138 operator<(const __key_value_iterator& __x, const __key_value_iterator& __y) {
139 return __x.__key_iter_ < __y.__key_iter_;
140 }
141
142 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend bool
143 operator>(const __key_value_iterator& __x, const __key_value_iterator& __y) {
144 return __y < __x;
145 }
146
147 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend bool
148 operator<=(const __key_value_iterator& __x, const __key_value_iterator& __y) {
149 return !(__y < __x);
150 }
151
152 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend bool
153 operator>=(const __key_value_iterator& __x, const __key_value_iterator& __y) {
154 return !(__x < __y);
155 }
156
157 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend auto
158 operator<=>(const __key_value_iterator& __x, const __key_value_iterator& __y)
159 requires three_way_comparable<__key_iterator>
160 {
161 return __x.__key_iter_ <=> __y.__key_iter_;
162 }
163
164 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend __key_value_iterator
165 operator+(const __key_value_iterator& __i, difference_type __n) {
166 auto __tmp = __i;
167 __tmp += __n;
168 return __tmp;
169 }
170
171 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend __key_value_iterator
172 operator+(difference_type __n, const __key_value_iterator& __i) {
173 return __i + __n;
174 }
175
176 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend __key_value_iterator
177 operator-(const __key_value_iterator& __i, difference_type __n) {
178 auto __tmp = __i;
179 __tmp -= __n;
180 return __tmp;
181 }
182
183 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 friend difference_type
184 operator-(const __key_value_iterator& __x, const __key_value_iterator& __y) {
185 return difference_type(__x.__key_iter_ - __y.__key_iter_);
186 }
187};
188
189template <class _Owner, class _KeyContainer, class _MappedContainer, bool _Const>
190struct __product_iterator_traits<__key_value_iterator<_Owner, _KeyContainer, _MappedContainer, _Const>> {
191 static constexpr size_t __size = 2;
192
193 template <size_t _Nth, class _Iter>
194 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 static decltype(auto) __get_iterator_element(_Iter&& __it)
195 requires(_Nth <= 1)
196 {
197 if constexpr (_Nth == 0) {
198 return std::forward<_Iter>(__it).__key_iter_;
199 } else {
200 return std::forward<_Iter>(__it).__mapped_iter_;
201 }
202 }
203
204 template <class _KeyIter, class _MappedIter>
205 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 static auto
206 __make_product_iterator(_KeyIter&& __key_iter, _MappedIter&& __mapped_iter) {
207 return __key_value_iterator<_Owner, _KeyContainer, _MappedContainer, _Const>(
208 std::forward<_KeyIter>(__key_iter), std::forward<_MappedIter>(__mapped_iter));
209 }
210};
211
212_LIBCPP_END_NAMESPACE_STD
213
214#endif // _LIBCPP_STD_VER >= 23
215
216_LIBCPP_POP_MACROS
217
218#endif // _LIBCPP___FLAT_MAP_KEY_VALUE_ITERATOR_H