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 <__utility/forward.h> 20 #include <concepts> 21 #include <type_traits> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 #pragma GCC system_header 25 #endif 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 29 #if !defined(_LIBCPP_HAS_NO_RANGES) 30 31 // [iterator.concept.readable] 32 template<class _In> 33 concept __indirectly_readable_impl = 34 requires(const _In __i) { 35 typename iter_value_t<_In>; 36 typename iter_reference_t<_In>; 37 typename iter_rvalue_reference_t<_In>; 38 { *__i } -> same_as<iter_reference_t<_In>>; 39 { ranges::iter_move(__i) } -> same_as<iter_rvalue_reference_t<_In>>; 40 } && 41 common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> && 42 common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> && 43 common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>; 44 45 template<class _In> 46 concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In>>; 47 48 template<indirectly_readable _Tp> 49 using iter_common_reference_t = common_reference_t<iter_reference_t<_Tp>, iter_value_t<_Tp>&>; 50 51 // [iterator.concept.writable] 52 template<class _Out, class _Tp> 53 concept indirectly_writable = 54 requires(_Out&& __o, _Tp&& __t) { 55 *__o = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 56 *_VSTD::forward<_Out>(__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 57 const_cast<const iter_reference_t<_Out>&&>(*__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 58 const_cast<const iter_reference_t<_Out>&&>(*_VSTD::forward<_Out>(__o)) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 59 }; 60 61 // [iterator.concept.winc] 62 template<class _Tp> 63 concept __integer_like = integral<_Tp> && !same_as<_Tp, bool>; 64 65 template<class _Tp> 66 concept __signed_integer_like = signed_integral<_Tp>; 67 68 template<class _Ip> 69 concept weakly_incrementable = 70 // TODO: remove this once the clang bug is fixed (bugs.llvm.org/PR48173). 71 !same_as<_Ip, bool> && // Currently, clang does not handle bool correctly. 72 movable<_Ip> && 73 requires(_Ip __i) { 74 typename iter_difference_t<_Ip>; 75 requires __signed_integer_like<iter_difference_t<_Ip>>; 76 { ++__i } -> same_as<_Ip&>; // not required to be equality-preserving 77 __i++; // not required to be equality-preserving 78 }; 79 80 // [iterator.concept.inc] 81 template<class _Ip> 82 concept incrementable = 83 regular<_Ip> && 84 weakly_incrementable<_Ip> && 85 requires(_Ip __i) { 86 { __i++ } -> same_as<_Ip>; 87 }; 88 89 // [iterator.concept.iterator] 90 template<class _Ip> 91 concept input_or_output_iterator = 92 requires(_Ip __i) { 93 { *__i } -> __referenceable; 94 } && 95 weakly_incrementable<_Ip>; 96 97 // [iterator.concept.sentinel] 98 template<class _Sp, class _Ip> 99 concept sentinel_for = 100 semiregular<_Sp> && 101 input_or_output_iterator<_Ip> && 102 __weakly_equality_comparable_with<_Sp, _Ip>; 103 104 template<class, class> 105 inline constexpr bool disable_sized_sentinel_for = false; 106 107 template<class _Sp, class _Ip> 108 concept sized_sentinel_for = 109 sentinel_for<_Sp, _Ip> && 110 !disable_sized_sentinel_for<remove_cv_t<_Sp>, remove_cv_t<_Ip>> && 111 requires(const _Ip& __i, const _Sp& __s) { 112 { __s - __i } -> same_as<iter_difference_t<_Ip>>; 113 { __i - __s } -> same_as<iter_difference_t<_Ip>>; 114 }; 115 116 // [iterator.concept.input] 117 template<class _Ip> 118 concept input_iterator = 119 input_or_output_iterator<_Ip> && 120 indirectly_readable<_Ip> && 121 requires { typename _ITER_CONCEPT<_Ip>; } && 122 derived_from<_ITER_CONCEPT<_Ip>, input_iterator_tag>; 123 124 // [iterator.concept.output] 125 template<class _Ip, class _Tp> 126 concept output_iterator = 127 input_or_output_iterator<_Ip> && 128 indirectly_writable<_Ip, _Tp> && 129 requires (_Ip __it, _Tp&& __t) { 130 *__it++ = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving 131 }; 132 133 // [iterator.concept.forward] 134 template<class _Ip> 135 concept forward_iterator = 136 input_iterator<_Ip> && 137 derived_from<_ITER_CONCEPT<_Ip>, forward_iterator_tag> && 138 incrementable<_Ip> && 139 sentinel_for<_Ip, _Ip>; 140 141 // [iterator.concept.bidir] 142 template<class _Ip> 143 concept bidirectional_iterator = 144 forward_iterator<_Ip> && 145 derived_from<_ITER_CONCEPT<_Ip>, bidirectional_iterator_tag> && 146 requires(_Ip __i) { 147 { --__i } -> same_as<_Ip&>; 148 { __i-- } -> same_as<_Ip>; 149 }; 150 151 template<class _Ip> 152 concept random_access_iterator = 153 bidirectional_iterator<_Ip> && 154 derived_from<_ITER_CONCEPT<_Ip>, random_access_iterator_tag> && 155 totally_ordered<_Ip> && 156 sized_sentinel_for<_Ip, _Ip> && 157 requires(_Ip __i, const _Ip __j, const iter_difference_t<_Ip> __n) { 158 { __i += __n } -> same_as<_Ip&>; 159 { __j + __n } -> same_as<_Ip>; 160 { __n + __j } -> same_as<_Ip>; 161 { __i -= __n } -> same_as<_Ip&>; 162 { __j - __n } -> same_as<_Ip>; 163 { __j[__n] } -> same_as<iter_reference_t<_Ip>>; 164 }; 165 166 template<class _Ip> 167 concept contiguous_iterator = 168 random_access_iterator<_Ip> && 169 derived_from<_ITER_CONCEPT<_Ip>, contiguous_iterator_tag> && 170 is_lvalue_reference_v<iter_reference_t<_Ip>> && 171 same_as<iter_value_t<_Ip>, remove_cvref_t<iter_reference_t<_Ip>>> && 172 requires(const _Ip& __i) { 173 { _VSTD::to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_Ip>>>; 174 }; 175 176 template<class _Ip> 177 concept __has_arrow = input_iterator<_Ip> && (is_pointer_v<_Ip> || requires(_Ip __i) { __i.operator->(); }); 178 179 // [indirectcallable.indirectinvocable] 180 template<class _Fp, class _It> 181 concept indirectly_unary_invocable = 182 indirectly_readable<_It> && 183 copy_constructible<_Fp> && 184 invocable<_Fp&, iter_value_t<_It>&> && 185 invocable<_Fp&, iter_reference_t<_It>> && 186 invocable<_Fp&, iter_common_reference_t<_It>> && 187 common_reference_with< 188 invoke_result_t<_Fp&, iter_value_t<_It>&>, 189 invoke_result_t<_Fp&, iter_reference_t<_It>>>; 190 191 template<class _Fp, class _It> 192 concept indirectly_regular_unary_invocable = 193 indirectly_readable<_It> && 194 copy_constructible<_Fp> && 195 regular_invocable<_Fp&, iter_value_t<_It>&> && 196 regular_invocable<_Fp&, iter_reference_t<_It>> && 197 regular_invocable<_Fp&, iter_common_reference_t<_It>> && 198 common_reference_with< 199 invoke_result_t<_Fp&, iter_value_t<_It>&>, 200 invoke_result_t<_Fp&, iter_reference_t<_It>>>; 201 202 template<class _Fp, class _It> 203 concept indirect_unary_predicate = 204 indirectly_readable<_It> && 205 copy_constructible<_Fp> && 206 predicate<_Fp&, iter_value_t<_It>&> && 207 predicate<_Fp&, iter_reference_t<_It>> && 208 predicate<_Fp&, iter_common_reference_t<_It>>; 209 210 template<class _Fp, class _It1, class _It2> 211 concept indirect_binary_predicate = 212 indirectly_readable<_It1> && indirectly_readable<_It2> && 213 copy_constructible<_Fp> && 214 predicate<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> && 215 predicate<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> && 216 predicate<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> && 217 predicate<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> && 218 predicate<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>; 219 220 template<class _Fp, class _It1, class _It2 = _It1> 221 concept indirect_equivalence_relation = 222 indirectly_readable<_It1> && indirectly_readable<_It2> && 223 copy_constructible<_Fp> && 224 equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> && 225 equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> && 226 equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> && 227 equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> && 228 equivalence_relation<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>; 229 230 template<class _Fp, class _It1, class _It2 = _It1> 231 concept indirect_strict_weak_order = 232 indirectly_readable<_It1> && indirectly_readable<_It2> && 233 copy_constructible<_Fp> && 234 strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> && 235 strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> && 236 strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> && 237 strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> && 238 strict_weak_order<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>; 239 240 template<class _Fp, class... _Its> 241 requires (indirectly_readable<_Its> && ...) && invocable<_Fp, iter_reference_t<_Its>...> 242 using indirect_result_t = invoke_result_t<_Fp, iter_reference_t<_Its>...>; 243 244 template<class _In, class _Out> 245 concept indirectly_movable = 246 indirectly_readable<_In> && 247 indirectly_writable<_Out, iter_rvalue_reference_t<_In>>; 248 249 template<class _In, class _Out> 250 concept indirectly_movable_storable = 251 indirectly_movable<_In, _Out> && 252 indirectly_writable<_Out, iter_value_t<_In>> && 253 movable<iter_value_t<_In>> && 254 constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>> && 255 assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>; 256 257 // Note: indirectly_swappable is located in iter_swap.h to prevent a dependency cycle 258 // (both iter_swap and indirectly_swappable require indirectly_readable). 259 260 #endif // !defined(_LIBCPP_HAS_NO_RANGES) 261 262 _LIBCPP_END_NAMESPACE_STD 263 264 #endif // _LIBCPP___ITERATOR_CONCEPTS_H 265