master
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_STATIC_BOUNDED_ITER_H
11#define _LIBCPP___ITERATOR_STATIC_BOUNDED_ITER_H
12
13#include <__assert>
14#include <__compare/ordering.h>
15#include <__compare/three_way_comparable.h>
16#include <__config>
17#include <__cstddef/size_t.h>
18#include <__iterator/iterator_traits.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#include <__utility/move.h>
28
29#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
30# pragma GCC system_header
31#endif
32
33_LIBCPP_PUSH_MACROS
34#include <__undef_macros>
35
36_LIBCPP_BEGIN_NAMESPACE_STD
37
38template <class _Iterator, size_t _Size>
39struct __static_bounded_iter_storage {
40 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter_storage() = default;
41 _LIBCPP_HIDE_FROM_ABI
42 _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __static_bounded_iter_storage(_Iterator __current, _Iterator __begin)
43 : __current_(__current), __begin_(__begin) {}
44
45 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator& __current() _NOEXCEPT { return __current_; }
46 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __current() const _NOEXCEPT { return __current_; }
47 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __begin() const _NOEXCEPT { return __begin_; }
48 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __end() const _NOEXCEPT { return __begin_ + _Size; }
49
50private:
51 _Iterator __current_; // current iterator
52 _Iterator __begin_; // start of the valid range, which is [__begin_, __begin_ + _Size)
53};
54
55template <class _Iterator>
56struct __static_bounded_iter_storage<_Iterator, 0> {
57 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter_storage() = default;
58 _LIBCPP_HIDE_FROM_ABI
59 _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __static_bounded_iter_storage(_Iterator __current, _Iterator /* __begin */)
60 : __current_(__current) {}
61
62 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator& __current() _NOEXCEPT { return __current_; }
63 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __current() const _NOEXCEPT { return __current_; }
64 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __begin() const _NOEXCEPT { return __current_; }
65 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __end() const _NOEXCEPT { return __current_; }
66
67private:
68 _Iterator __current_; // current iterator
69};
70
71// This is an iterator wrapper for contiguous iterators that points within a range
72// whose size is known at compile-time. This is very similar to `__bounded_iter`,
73// except that we don't have to store the end of the range in physical memory since
74// it can be computed from the start of the range.
75//
76// The operations on which this iterator wrapper traps are the same as `__bounded_iter`.
77template <class _Iterator, size_t _Size>
78struct __static_bounded_iter {
79 static_assert(__libcpp_is_contiguous_iterator<_Iterator>::value,
80 "Only contiguous iterators can be adapted by __static_bounded_iter.");
81
82 using value_type = typename iterator_traits<_Iterator>::value_type;
83 using difference_type = typename iterator_traits<_Iterator>::difference_type;
84 using pointer = typename iterator_traits<_Iterator>::pointer;
85 using reference = typename iterator_traits<_Iterator>::reference;
86 using iterator_category = typename iterator_traits<_Iterator>::iterator_category;
87#if _LIBCPP_STD_VER >= 20
88 using iterator_concept = contiguous_iterator_tag;
89#endif
90
91 // Create a singular iterator.
92 //
93 // Such an iterator points past the end of an empty range, so it is not dereferenceable.
94 // Operations like comparison and assignment are valid.
95 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter() = default;
96
97 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter(__static_bounded_iter const&) = default;
98 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter(__static_bounded_iter&&) = default;
99
100 template <class _OtherIterator,
101 __enable_if_t<
102 _And< is_convertible<const _OtherIterator&, _Iterator>,
103 _Or<is_same<reference, __iter_reference<_OtherIterator> >,
104 is_same<reference, __make_const_lvalue_ref<__iter_reference<_OtherIterator> > > > >::value,
105 int> = 0>
106 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
107 __static_bounded_iter(__static_bounded_iter<_OtherIterator, _Size> const& __other) _NOEXCEPT
108 : __storage_(__other.__storage_.__current(), __other.__storage_.__begin()) {}
109
110 // Assign a bounded iterator to another one, rebinding the bounds of the iterator as well.
111 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter& operator=(__static_bounded_iter const&) = default;
112 _LIBCPP_HIDE_FROM_ABI __static_bounded_iter& operator=(__static_bounded_iter&&) = default;
113
114private:
115 // Create an iterator wrapping the given iterator, and whose bounds are described
116 // by the provided [begin, begin + _Size] range.
117 _LIBCPP_HIDE_FROM_ABI
118 _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __static_bounded_iter(_Iterator __current, _Iterator __begin)
119 : __storage_(__current, __begin) {
120 _LIBCPP_ASSERT_INTERNAL(
121 __begin <= __current, "__static_bounded_iter(current, begin): current and begin are inconsistent");
122 _LIBCPP_ASSERT_INTERNAL(
123 __current <= __end(), "__static_bounded_iter(current, begin): current and (begin + Size) are inconsistent");
124 }
125
126 template <size_t _Sz, class _It>
127 friend _LIBCPP_CONSTEXPR __static_bounded_iter<_It, _Sz> __make_static_bounded_iter(_It, _It);
128
129public:
130 // Dereference and indexing operations.
131 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference operator*() const _NOEXCEPT {
132 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
133 __current() != __end(), "__static_bounded_iter::operator*: Attempt to dereference an iterator at the end");
134 return *__current();
135 }
136
137 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pointer operator->() const _NOEXCEPT {
138 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
139 __current() != __end(), "__static_bounded_iter::operator->: Attempt to dereference an iterator at the end");
140 return std::__to_address(__current());
141 }
142
143 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference operator[](difference_type __n) const _NOEXCEPT {
144 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
145 __n >= __begin() - __current(),
146 "__static_bounded_iter::operator[]: Attempt to index an iterator past the start");
147 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
148 __n < __end() - __current(),
149 "__static_bounded_iter::operator[]: Attempt to index an iterator at or past the end");
150 return __current()[__n];
151 }
152
153 // Arithmetic operations.
154 //
155 // These operations check that the iterator remains within `[begin, end]`.
156 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter& operator++() _NOEXCEPT {
157 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
158 __current() != __end(), "__static_bounded_iter::operator++: Attempt to advance an iterator past the end");
159 ++__current();
160 return *this;
161 }
162 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter operator++(int) _NOEXCEPT {
163 __static_bounded_iter __tmp(*this);
164 ++*this;
165 return __tmp;
166 }
167
168 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter& operator--() _NOEXCEPT {
169 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
170 __current() != __begin(), "__static_bounded_iter::operator--: Attempt to rewind an iterator past the start");
171 --__current();
172 return *this;
173 }
174 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter operator--(int) _NOEXCEPT {
175 __static_bounded_iter __tmp(*this);
176 --*this;
177 return __tmp;
178 }
179
180 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter& operator+=(difference_type __n) _NOEXCEPT {
181 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
182 __n >= __begin() - __current(),
183 "__static_bounded_iter::operator+=: Attempt to rewind an iterator past the start");
184 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
185 __n <= __end() - __current(), "__static_bounded_iter::operator+=: Attempt to advance an iterator past the end");
186 __current() += __n;
187 return *this;
188 }
189 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 friend __static_bounded_iter
190 operator+(__static_bounded_iter const& __self, difference_type __n) _NOEXCEPT {
191 __static_bounded_iter __tmp(__self);
192 __tmp += __n;
193 return __tmp;
194 }
195 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 friend __static_bounded_iter
196 operator+(difference_type __n, __static_bounded_iter const& __self) _NOEXCEPT {
197 __static_bounded_iter __tmp(__self);
198 __tmp += __n;
199 return __tmp;
200 }
201
202 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __static_bounded_iter& operator-=(difference_type __n) _NOEXCEPT {
203 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
204 __n <= __current() - __begin(),
205 "__static_bounded_iter::operator-=: Attempt to rewind an iterator past the start");
206 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
207 __n >= __current() - __end(), "__static_bounded_iter::operator-=: Attempt to advance an iterator past the end");
208 __current() -= __n;
209 return *this;
210 }
211 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 friend __static_bounded_iter
212 operator-(__static_bounded_iter const& __self, difference_type __n) _NOEXCEPT {
213 __static_bounded_iter __tmp(__self);
214 __tmp -= __n;
215 return __tmp;
216 }
217 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 friend difference_type
218 operator-(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
219 return __x.__current() - __y.__current();
220 }
221
222 // Comparison operations.
223 //
224 // These operations do not check whether the iterators are within their bounds.
225 // The valid range for each iterator is also not considered as part of the comparison,
226 // i.e. two iterators pointing to the same location will be considered equal even
227 // if they have different validity ranges.
228 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
229 operator==(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
230 return __x.__current() == __y.__current();
231 }
232
233#if _LIBCPP_STD_VER <= 17
234 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
235 operator!=(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
236 return __x.__current() != __y.__current();
237 }
238
239 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
240 operator<(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
241 return __x.__current() < __y.__current();
242 }
243 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
244 operator>(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
245 return __x.__current() > __y.__current();
246 }
247 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
248 operator<=(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
249 return __x.__current() <= __y.__current();
250 }
251 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR friend bool
252 operator>=(__static_bounded_iter const& __x, __static_bounded_iter const& __y) _NOEXCEPT {
253 return __x.__current() >= __y.__current();
254 }
255
256#else
257 _LIBCPP_HIDE_FROM_ABI constexpr friend strong_ordering
258 operator<=>(__static_bounded_iter const& __x, __static_bounded_iter const& __y) noexcept {
259 if constexpr (three_way_comparable<_Iterator, strong_ordering>) {
260 return __x.__current() <=> __y.__current();
261 } else {
262 if (__x.__current() < __y.__current())
263 return strong_ordering::less;
264
265 if (__x.__current() == __y.__current())
266 return strong_ordering::equal;
267
268 return strong_ordering::greater;
269 }
270 }
271#endif // _LIBCPP_STD_VER >= 20
272
273private:
274 template <class>
275 friend struct pointer_traits;
276 template <class, size_t>
277 friend struct __static_bounded_iter;
278 __static_bounded_iter_storage<_Iterator, _Size> __storage_;
279
280 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator& __current() _NOEXCEPT {
281 return __storage_.__current();
282 }
283 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __current() const _NOEXCEPT {
284 return __storage_.__current();
285 }
286 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __begin() const _NOEXCEPT {
287 return __storage_.__begin();
288 }
289 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iterator __end() const _NOEXCEPT { return __storage_.__end(); }
290};
291
292template <size_t _Size, class _It>
293_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __static_bounded_iter<_It, _Size>
294__make_static_bounded_iter(_It __it, _It __begin) {
295 return __static_bounded_iter<_It, _Size>(std::move(__it), std::move(__begin));
296}
297
298#if _LIBCPP_STD_VER <= 17
299template <class _Iterator, size_t _Size>
300struct __libcpp_is_contiguous_iterator<__static_bounded_iter<_Iterator, _Size> > : true_type {};
301#endif
302
303template <class _Iterator, size_t _Size>
304struct pointer_traits<__static_bounded_iter<_Iterator, _Size> > {
305 using pointer = __static_bounded_iter<_Iterator, _Size>;
306 using element_type = typename pointer_traits<_Iterator>::element_type;
307 using difference_type = typename pointer_traits<_Iterator>::difference_type;
308
309 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static element_type* to_address(pointer __it) _NOEXCEPT {
310 return std::__to_address(__it.__current());
311 }
312};
313
314_LIBCPP_END_NAMESPACE_STD
315
316_LIBCPP_POP_MACROS
317
318#endif // _LIBCPP___ITERATOR_STATIC_BOUNDED_ITER_H