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_CONCEPTS_H 11 #define _LIBCPP___ITERATOR_CONCEPTS_H 12 13 #include <__config> 14 #include <__iterator/incrementable_traits.h> 15 #include <__iterator/iter_move.h> 16 #include <__iterator/iterator_traits.h> 17 #include <__iterator/readable_traits.h> 18 #include <__memory/pointer_traits.h> 19 #include <concepts> 20 #include <type_traits> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 #pragma GCC system_header 24 #endif 25 26 _LIBCPP_PUSH_MACROS 27 #include <__undef_macros> 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 #if !defined(_LIBCPP_HAS_NO_RANGES) 32 33 // clang-format off 34 35 // [iterator.concept.readable] 36 template<class _In> 37 concept __indirectly_readable_impl = 38 requires(const _In __i) { 39 typename iter_value_t<_In>; 40 typename iter_reference_t<_In>; 41 typename iter_rvalue_reference_t<_In>; 42 { *__i } -> same_as<iter_reference_t<_In> >; 43 { ranges::iter_move(__i) } -> same_as<iter_rvalue_reference_t<_In> >; 44 } && 45 common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> && 46 common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> && 47 common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>; 48 49 template<class _In> 50 concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In> >; 51 52 template<indirectly_readable _Tp> 53 using iter_common_reference_t = common_reference_t<iter_reference_t<_Tp>, iter_value_t<_Tp>&>; 54 55 // [iterator.concept.writable] 56 template<class _Out, class _Tp> 57 concept indirectly_writable = 58 requires(_Out&& __o, _Tp&& __t) { 59 *__o = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 60 *_VSTD::forward<_Out>(__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 61 const_cast<const iter_reference_t<_Out>&&>(*__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 62 const_cast<const iter_reference_t<_Out>&&>(*_VSTD::forward<_Out>(__o)) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 63 }; 64 65 // [iterator.concept.winc] 66 template<class _Tp> 67 concept __integer_like = integral<_Tp> && !same_as<_Tp, bool>; 68 69 template<class _Tp> 70 concept __signed_integer_like = signed_integral<_Tp>; 71 72 template<class _Ip> 73 concept weakly_incrementable = 74 default_initializable<_Ip> && 75 movable<_Ip> && 76 requires(_Ip __i) { 77 typename iter_difference_t<_Ip>; 78 requires __signed_integer_like<iter_difference_t<_Ip> >; 79 { ++__i } -> same_as<_Ip&>; // not required to be equality-preserving 80 __i++; // not required to be equality-preserving 81 }; 82 83 // [iterator.concept.inc] 84 template<class _Ip> 85 concept incrementable = 86 regular<_Ip> && 87 weakly_incrementable<_Ip> && 88 requires(_Ip __i) { 89 { __i++ } -> same_as<_Ip>; 90 }; 91 92 // [iterator.concept.iterator] 93 template<class _Ip> 94 concept input_or_output_iterator = 95 requires(_Ip __i) { 96 { *__i } -> __referenceable; 97 } && 98 weakly_incrementable<_Ip>; 99 100 // [iterator.concept.sentinel] 101 template<class _Sp, class _Ip> 102 concept sentinel_for = 103 semiregular<_Sp> && 104 input_or_output_iterator<_Ip> && 105 __weakly_equality_comparable_with<_Sp, _Ip>; 106 107 template<class, class> 108 inline constexpr bool disable_sized_sentinel_for = false; 109 110 template<class _Sp, class _Ip> 111 concept sized_sentinel_for = 112 sentinel_for<_Sp, _Ip> && 113 !disable_sized_sentinel_for<remove_cv_t<_Sp>, remove_cv_t<_Ip> > && 114 requires(const _Ip& __i, const _Sp& __s) { 115 { __s - __i } -> same_as<iter_difference_t<_Ip> >; 116 { __i - __s } -> same_as<iter_difference_t<_Ip> >; 117 }; 118 119 // [iterator.concept.input] 120 template<class _Ip> 121 concept input_iterator = 122 input_or_output_iterator<_Ip> && 123 indirectly_readable<_Ip> && 124 requires { typename _ITER_CONCEPT<_Ip>; } && 125 derived_from<_ITER_CONCEPT<_Ip>, input_iterator_tag>; 126 127 // [iterator.concept.forward] 128 template<class _Ip> 129 concept forward_iterator = 130 input_iterator<_Ip> && 131 derived_from<_ITER_CONCEPT<_Ip>, forward_iterator_tag> && 132 incrementable<_Ip> && 133 sentinel_for<_Ip, _Ip>; 134 135 // [iterator.concept.bidir] 136 template<class _Ip> 137 concept bidirectional_iterator = 138 forward_iterator<_Ip> && 139 derived_from<_ITER_CONCEPT<_Ip>, bidirectional_iterator_tag> && 140 requires(_Ip __i) { 141 { --__i } -> same_as<_Ip&>; 142 { __i-- } -> same_as<_Ip>; 143 }; 144 145 template<class _Ip> 146 concept random_access_iterator = 147 bidirectional_iterator<_Ip> && 148 derived_from<_ITER_CONCEPT<_Ip>, random_access_iterator_tag> && 149 totally_ordered<_Ip> && 150 sized_sentinel_for<_Ip, _Ip> && 151 requires(_Ip __i, const _Ip __j, const iter_difference_t<_Ip> __n) { 152 { __i += __n } -> same_as<_Ip&>; 153 { __j + __n } -> same_as<_Ip>; 154 { __n + __j } -> same_as<_Ip>; 155 { __i -= __n } -> same_as<_Ip&>; 156 { __j - __n } -> same_as<_Ip>; 157 { __j[__n] } -> same_as<iter_reference_t<_Ip>>; 158 }; 159 160 template<class _Ip> 161 concept contiguous_iterator = 162 random_access_iterator<_Ip> && 163 derived_from<_ITER_CONCEPT<_Ip>, contiguous_iterator_tag> && 164 is_lvalue_reference_v<iter_reference_t<_Ip>> && 165 same_as<iter_value_t<_Ip>, remove_cvref_t<iter_reference_t<_Ip>>> && 166 (is_pointer_v<_Ip> || requires { sizeof(__pointer_traits_element_type<_Ip>); }) && 167 requires(const _Ip& __i) { 168 { _VSTD::to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_Ip>>>; 169 }; 170 171 // clang-format on 172 173 #endif // !defined(_LIBCPP_HAS_NO_RANGES) 174 175 _LIBCPP_END_NAMESPACE_STD 176 177 _LIBCPP_POP_MACROS 178 179 #endif // _LIBCPP___ITERATOR_CONCEPTS_H 180