Yi Kong | 878f994 | 2023-12-13 12:55:04 +0900 | [diff] [blame^] | 1 | //===----------------------------------------------------------------------===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H |
| 10 | #define _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H |
| 11 | |
| 12 | #include <__algorithm/iter_swap.h> |
| 13 | #include <__algorithm/ranges_iterator_concept.h> |
| 14 | #include <__config> |
| 15 | #include <__iterator/advance.h> |
| 16 | #include <__iterator/distance.h> |
| 17 | #include <__iterator/incrementable_traits.h> |
| 18 | #include <__iterator/iter_move.h> |
| 19 | #include <__iterator/iter_swap.h> |
| 20 | #include <__iterator/iterator_traits.h> |
| 21 | #include <__iterator/next.h> |
| 22 | #include <__iterator/prev.h> |
| 23 | #include <__iterator/readable_traits.h> |
| 24 | #include <__type_traits/enable_if.h> |
| 25 | #include <__type_traits/is_reference.h> |
| 26 | #include <__type_traits/is_same.h> |
| 27 | #include <__type_traits/remove_cvref.h> |
| 28 | #include <__utility/declval.h> |
| 29 | #include <__utility/forward.h> |
| 30 | #include <__utility/move.h> |
| 31 | |
| 32 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 33 | # pragma GCC system_header |
| 34 | #endif |
| 35 | |
| 36 | _LIBCPP_PUSH_MACROS |
| 37 | #include <__undef_macros> |
| 38 | |
| 39 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 40 | |
| 41 | template <class _AlgPolicy> struct _IterOps; |
| 42 | |
| 43 | #if _LIBCPP_STD_VER >= 20 |
| 44 | struct _RangeAlgPolicy {}; |
| 45 | |
| 46 | template <> |
| 47 | struct _IterOps<_RangeAlgPolicy> { |
| 48 | |
| 49 | template <class _Iter> |
| 50 | using __value_type = iter_value_t<_Iter>; |
| 51 | |
| 52 | template <class _Iter> |
| 53 | using __iterator_category = ranges::__iterator_concept<_Iter>; |
| 54 | |
| 55 | template <class _Iter> |
| 56 | using __difference_type = iter_difference_t<_Iter>; |
| 57 | |
| 58 | static constexpr auto advance = ranges::advance; |
| 59 | static constexpr auto distance = ranges::distance; |
| 60 | static constexpr auto __iter_move = ranges::iter_move; |
| 61 | static constexpr auto iter_swap = ranges::iter_swap; |
| 62 | static constexpr auto next = ranges::next; |
| 63 | static constexpr auto prev = ranges::prev; |
| 64 | static constexpr auto __advance_to = ranges::advance; |
| 65 | }; |
| 66 | |
| 67 | #endif |
| 68 | |
| 69 | struct _ClassicAlgPolicy {}; |
| 70 | |
| 71 | template <> |
| 72 | struct _IterOps<_ClassicAlgPolicy> { |
| 73 | |
| 74 | template <class _Iter> |
| 75 | using __value_type = typename iterator_traits<_Iter>::value_type; |
| 76 | |
| 77 | template <class _Iter> |
| 78 | using __iterator_category = typename iterator_traits<_Iter>::iterator_category; |
| 79 | |
| 80 | template <class _Iter> |
| 81 | using __difference_type = typename iterator_traits<_Iter>::difference_type; |
| 82 | |
| 83 | // advance |
| 84 | template <class _Iter, class _Distance> |
| 85 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 86 | static void advance(_Iter& __iter, _Distance __count) { |
| 87 | std::advance(__iter, __count); |
| 88 | } |
| 89 | |
| 90 | // distance |
| 91 | template <class _Iter> |
| 92 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 93 | static typename iterator_traits<_Iter>::difference_type distance(_Iter __first, _Iter __last) { |
| 94 | return std::distance(__first, __last); |
| 95 | } |
| 96 | |
| 97 | template <class _Iter> |
| 98 | using __deref_t = decltype(*std::declval<_Iter&>()); |
| 99 | |
| 100 | template <class _Iter> |
| 101 | using __move_t = decltype(std::move(*std::declval<_Iter&>())); |
| 102 | |
| 103 | template <class _Iter> |
| 104 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 105 | static void __validate_iter_reference() { |
| 106 | static_assert(is_same<__deref_t<_Iter>, typename iterator_traits<__remove_cvref_t<_Iter> >::reference>::value, |
| 107 | "It looks like your iterator's `iterator_traits<It>::reference` does not match the return type of " |
| 108 | "dereferencing the iterator, i.e., calling `*it`. This is undefined behavior according to [input.iterators] " |
| 109 | "and can lead to dangling reference issues at runtime, so we are flagging this."); |
| 110 | } |
| 111 | |
| 112 | // iter_move |
| 113 | template <class _Iter> |
| 114 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 static |
| 115 | // If the result of dereferencing `_Iter` is a reference type, deduce the result of calling `std::move` on it. Note |
| 116 | // that the C++03 mode doesn't support `decltype(auto)` as the return type. |
| 117 | __enable_if_t< |
| 118 | is_reference<__deref_t<_Iter> >::value, |
| 119 | __move_t<_Iter> > |
| 120 | __iter_move(_Iter&& __i) { |
| 121 | __validate_iter_reference<_Iter>(); |
| 122 | |
| 123 | return std::move(*std::forward<_Iter>(__i)); |
| 124 | } |
| 125 | |
| 126 | template <class _Iter> |
| 127 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 static |
| 128 | // If the result of dereferencing `_Iter` is a value type, deduce the return value of this function to also be a |
| 129 | // value -- otherwise, after `operator*` returns a temporary, this function would return a dangling reference to that |
| 130 | // temporary. Note that the C++03 mode doesn't support `auto` as the return type. |
| 131 | __enable_if_t< |
| 132 | !is_reference<__deref_t<_Iter> >::value, |
| 133 | __deref_t<_Iter> > |
| 134 | __iter_move(_Iter&& __i) { |
| 135 | __validate_iter_reference<_Iter>(); |
| 136 | |
| 137 | return *std::forward<_Iter>(__i); |
| 138 | } |
| 139 | |
| 140 | // iter_swap |
| 141 | template <class _Iter1, class _Iter2> |
| 142 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 143 | static void iter_swap(_Iter1&& __a, _Iter2&& __b) { |
| 144 | std::iter_swap(std::forward<_Iter1>(__a), std::forward<_Iter2>(__b)); |
| 145 | } |
| 146 | |
| 147 | // next |
| 148 | template <class _Iterator> |
| 149 | _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 150 | _Iterator next(_Iterator, _Iterator __last) { |
| 151 | return __last; |
| 152 | } |
| 153 | |
| 154 | template <class _Iter> |
| 155 | _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 156 | __remove_cvref_t<_Iter> next(_Iter&& __it, |
| 157 | typename iterator_traits<__remove_cvref_t<_Iter> >::difference_type __n = 1) { |
| 158 | return std::next(std::forward<_Iter>(__it), __n); |
| 159 | } |
| 160 | |
| 161 | // prev |
| 162 | template <class _Iter> |
| 163 | _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 164 | __remove_cvref_t<_Iter> prev(_Iter&& __iter, |
| 165 | typename iterator_traits<__remove_cvref_t<_Iter> >::difference_type __n = 1) { |
| 166 | return std::prev(std::forward<_Iter>(__iter), __n); |
| 167 | } |
| 168 | |
| 169 | template <class _Iter> |
| 170 | _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 171 | void __advance_to(_Iter& __first, _Iter __last) { |
| 172 | __first = __last; |
| 173 | } |
| 174 | }; |
| 175 | |
| 176 | _LIBCPP_END_NAMESPACE_STD |
| 177 | |
| 178 | _LIBCPP_POP_MACROS |
| 179 | |
| 180 | #endif // _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H |