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 <__concepts/arithmetic.h> 14 #include <__concepts/assignable.h> 15 #include <__concepts/common_reference_with.h> 16 #include <__concepts/constructible.h> 17 #include <__concepts/copyable.h> 18 #include <__concepts/derived_from.h> 19 #include <__concepts/equality_comparable.h> 20 #include <__concepts/invocable.h> 21 #include <__concepts/movable.h> 22 #include <__concepts/predicate.h> 23 #include <__concepts/regular.h> 24 #include <__concepts/relation.h> 25 #include <__concepts/same_as.h> 26 #include <__concepts/semiregular.h> 27 #include <__concepts/totally_ordered.h> 28 #include <__config> 29 #include <__iterator/incrementable_traits.h> 30 #include <__iterator/iter_move.h> 31 #include <__iterator/iterator_traits.h> 32 #include <__iterator/readable_traits.h> 33 #include <__memory/pointer_traits.h> 34 #include <__type_traits/add_pointer.h> 35 #include <__type_traits/common_reference.h> 36 #include <__type_traits/integral_constant.h> 37 #include <__type_traits/invoke.h> 38 #include <__type_traits/is_pointer.h> 39 #include <__type_traits/is_primary_template.h> 40 #include <__type_traits/is_reference.h> 41 #include <__type_traits/remove_cv.h> 42 #include <__type_traits/remove_cvref.h> 43 #include <__utility/forward.h> 44 45 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 46 # pragma GCC system_header 47 #endif 48 49 _LIBCPP_BEGIN_NAMESPACE_STD 50 51 #if _LIBCPP_STD_VER >= 20 52 53 // [iterator.concept.readable] 54 template <class _In> 55 concept __indirectly_readable_impl = 56 requires(const _In __i) { 57 typename iter_value_t<_In>; 58 typename iter_reference_t<_In>; 59 typename iter_rvalue_reference_t<_In>; 60 { *__i } -> same_as<iter_reference_t<_In>>; 61 { ranges::iter_move(__i) } -> same_as<iter_rvalue_reference_t<_In>>; 62 } && common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> && 63 common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> && 64 common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>; 65 66 template <class _In> 67 concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In>>; 68 69 template <class _Tp> 70 using __projected_iterator_t _LIBCPP_NODEBUG = typename _Tp::__projected_iterator; 71 72 template <class _Tp> 73 using __projected_projection_t _LIBCPP_NODEBUG = typename _Tp::__projected_projection; 74 75 template <class _Tp> 76 concept __specialization_of_projected = requires { 77 typename __projected_iterator_t<_Tp>; 78 typename __projected_projection_t<_Tp>; 79 } && __is_primary_template<_Tp>::value; 80 81 template <class _Tp> 82 struct __indirect_value_t_impl { 83 using type = iter_value_t<_Tp>&; 84 }; 85 template <__specialization_of_projected _Tp> 86 struct __indirect_value_t_impl<_Tp> { 87 using type = invoke_result_t<__projected_projection_t<_Tp>&, 88 typename __indirect_value_t_impl<__projected_iterator_t<_Tp>>::type>; 89 }; 90 91 template <indirectly_readable _Tp> 92 using __indirect_value_t _LIBCPP_NODEBUG = typename __indirect_value_t_impl<_Tp>::type; 93 94 template <indirectly_readable _Tp> 95 using iter_common_reference_t = common_reference_t<iter_reference_t<_Tp>, __indirect_value_t<_Tp>>; 96 97 // [iterator.concept.writable] 98 template <class _Out, class _Tp> 99 concept indirectly_writable = requires(_Out&& __o, _Tp&& __t) { 100 *__o = std::forward<_Tp>(__t); // not required to be equality-preserving 101 *std::forward<_Out>(__o) = std::forward<_Tp>(__t); // not required to be equality-preserving 102 const_cast<const iter_reference_t<_Out>&&>(*__o) = std::forward<_Tp>(__t); // not required to be equality-preserving 103 const_cast<const iter_reference_t<_Out>&&>(*std::forward<_Out>(__o)) = 104 std::forward<_Tp>(__t); // not required to be equality-preserving 105 }; 106 107 // [iterator.concept.winc] 108 template <class _Tp> 109 concept __integer_like = integral<_Tp> && !same_as<_Tp, bool>; 110 111 template <class _Tp> 112 concept __signed_integer_like = signed_integral<_Tp>; 113 114 template <class _Ip> 115 concept weakly_incrementable = 116 // TODO: remove this once the clang bug is fixed (bugs.llvm.org/PR48173). 117 !same_as<_Ip, bool> && // Currently, clang does not handle bool correctly. 118 movable<_Ip> && requires(_Ip __i) { 119 typename iter_difference_t<_Ip>; 120 requires __signed_integer_like<iter_difference_t<_Ip>>; 121 { ++__i } -> same_as<_Ip&>; // not required to be equality-preserving 122 __i++; // not required to be equality-preserving 123 }; 124 125 // [iterator.concept.inc] 126 template <class _Ip> 127 concept incrementable = regular<_Ip> && weakly_incrementable<_Ip> && requires(_Ip __i) { 128 { __i++ } -> same_as<_Ip>; 129 }; 130 131 // [iterator.concept.iterator] 132 template <class _Ip> 133 concept input_or_output_iterator = requires(_Ip __i) { 134 { *__i } -> __can_reference; 135 } && weakly_incrementable<_Ip>; 136 137 // [iterator.concept.sentinel] 138 template <class _Sp, class _Ip> 139 concept sentinel_for = semiregular<_Sp> && input_or_output_iterator<_Ip> && __weakly_equality_comparable_with<_Sp, _Ip>; 140 141 template <class, class> 142 inline constexpr bool disable_sized_sentinel_for = false; 143 144 template <class _Sp, class _Ip> 145 concept sized_sentinel_for = 146 sentinel_for<_Sp, _Ip> && !disable_sized_sentinel_for<remove_cv_t<_Sp>, remove_cv_t<_Ip>> && 147 requires(const _Ip& __i, const _Sp& __s) { 148 { __s - __i } -> same_as<iter_difference_t<_Ip>>; 149 { __i - __s } -> same_as<iter_difference_t<_Ip>>; 150 }; 151 152 // [iterator.concept.input] 153 template <class _Ip> 154 concept input_iterator = input_or_output_iterator<_Ip> && indirectly_readable<_Ip> && requires { 155 typename _ITER_CONCEPT<_Ip>; 156 } && derived_from<_ITER_CONCEPT<_Ip>, input_iterator_tag>; 157 158 // [iterator.concept.output] 159 template <class _Ip, class _Tp> 160 concept output_iterator = 161 input_or_output_iterator<_Ip> && indirectly_writable<_Ip, _Tp> && requires(_Ip __it, _Tp&& __t) { 162 *__it++ = std::forward<_Tp>(__t); // not required to be equality-preserving 163 }; 164 165 // [iterator.concept.forward] 166 template <class _Ip> 167 concept forward_iterator = 168 input_iterator<_Ip> && derived_from<_ITER_CONCEPT<_Ip>, forward_iterator_tag> && incrementable<_Ip> && 169 sentinel_for<_Ip, _Ip>; 170 171 // [iterator.concept.bidir] 172 template <class _Ip> 173 concept bidirectional_iterator = 174 forward_iterator<_Ip> && derived_from<_ITER_CONCEPT<_Ip>, bidirectional_iterator_tag> && requires(_Ip __i) { 175 { --__i } -> same_as<_Ip&>; 176 { __i-- } -> same_as<_Ip>; 177 }; 178 179 template <class _Ip> 180 concept random_access_iterator = 181 bidirectional_iterator<_Ip> && derived_from<_ITER_CONCEPT<_Ip>, random_access_iterator_tag> && 182 totally_ordered<_Ip> && sized_sentinel_for<_Ip, _Ip> && 183 requires(_Ip __i, const _Ip __j, const iter_difference_t<_Ip> __n) { 184 { __i += __n } -> same_as<_Ip&>; 185 { __j + __n } -> same_as<_Ip>; 186 { __n + __j } -> same_as<_Ip>; 187 { __i -= __n } -> same_as<_Ip&>; 188 { __j - __n } -> same_as<_Ip>; 189 { __j[__n] } -> same_as<iter_reference_t<_Ip>>; 190 }; 191 192 template <class _Ip> 193 concept contiguous_iterator = 194 random_access_iterator<_Ip> && derived_from<_ITER_CONCEPT<_Ip>, contiguous_iterator_tag> && 195 is_lvalue_reference_v<iter_reference_t<_Ip>> && same_as<iter_value_t<_Ip>, remove_cvref_t<iter_reference_t<_Ip>>> && 196 requires(const _Ip& __i) { 197 { std::to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_Ip>>>; 198 }; 199 200 template <class _Ip> 201 concept __has_arrow = input_iterator<_Ip> && (is_pointer_v<_Ip> || requires(_Ip __i) { __i.operator->(); }); 202 203 // [indirectcallable.indirectinvocable] 204 template <class _Fp, class _It> 205 concept indirectly_unary_invocable = 206 indirectly_readable<_It> && copy_constructible<_Fp> && invocable<_Fp&, __indirect_value_t<_It>> && 207 invocable<_Fp&, iter_reference_t<_It>> && 208 common_reference_with< invoke_result_t<_Fp&, __indirect_value_t<_It>>, 209 invoke_result_t<_Fp&, iter_reference_t<_It>>>; 210 211 template <class _Fp, class _It> 212 concept indirectly_regular_unary_invocable = 213 indirectly_readable<_It> && copy_constructible<_Fp> && regular_invocable<_Fp&, __indirect_value_t<_It>> && 214 regular_invocable<_Fp&, iter_reference_t<_It>> && 215 common_reference_with< invoke_result_t<_Fp&, __indirect_value_t<_It>>, 216 invoke_result_t<_Fp&, iter_reference_t<_It>>>; 217 218 template <class _Fp, class _It> 219 concept indirect_unary_predicate = 220 indirectly_readable<_It> && copy_constructible<_Fp> && predicate<_Fp&, __indirect_value_t<_It>> && 221 predicate<_Fp&, iter_reference_t<_It>>; 222 223 template <class _Fp, class _It1, class _It2> 224 concept indirect_binary_predicate = 225 indirectly_readable<_It1> && indirectly_readable<_It2> && copy_constructible<_Fp> && 226 predicate<_Fp&, __indirect_value_t<_It1>, __indirect_value_t<_It2>> && 227 predicate<_Fp&, __indirect_value_t<_It1>, iter_reference_t<_It2>> && 228 predicate<_Fp&, iter_reference_t<_It1>, __indirect_value_t<_It2>> && 229 predicate<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>>; 230 231 template <class _Fp, class _It1, class _It2 = _It1> 232 concept indirect_equivalence_relation = 233 indirectly_readable<_It1> && indirectly_readable<_It2> && copy_constructible<_Fp> && 234 equivalence_relation<_Fp&, __indirect_value_t<_It1>, __indirect_value_t<_It2>> && 235 equivalence_relation<_Fp&, __indirect_value_t<_It1>, iter_reference_t<_It2>> && 236 equivalence_relation<_Fp&, iter_reference_t<_It1>, __indirect_value_t<_It2>> && 237 equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>>; 238 239 template <class _Fp, class _It1, class _It2 = _It1> 240 concept indirect_strict_weak_order = 241 indirectly_readable<_It1> && indirectly_readable<_It2> && copy_constructible<_Fp> && 242 strict_weak_order<_Fp&, __indirect_value_t<_It1>, __indirect_value_t<_It2>> && 243 strict_weak_order<_Fp&, __indirect_value_t<_It1>, iter_reference_t<_It2>> && 244 strict_weak_order<_Fp&, iter_reference_t<_It1>, __indirect_value_t<_It2>> && 245 strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>>; 246 247 template <class _Fp, class... _Its> 248 requires(indirectly_readable<_Its> && ...) && invocable<_Fp, iter_reference_t<_Its>...> 249 using indirect_result_t = invoke_result_t<_Fp, iter_reference_t<_Its>...>; 250 251 template <class _In, class _Out> 252 concept indirectly_movable = indirectly_readable<_In> && indirectly_writable<_Out, iter_rvalue_reference_t<_In>>; 253 254 template <class _In, class _Out> 255 concept indirectly_movable_storable = 256 indirectly_movable<_In, _Out> && indirectly_writable<_Out, iter_value_t<_In>> && movable<iter_value_t<_In>> && 257 constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>> && 258 assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>; 259 260 template <class _In, class _Out> 261 concept indirectly_copyable = indirectly_readable<_In> && indirectly_writable<_Out, iter_reference_t<_In>>; 262 263 template <class _In, class _Out> 264 concept indirectly_copyable_storable = 265 indirectly_copyable<_In, _Out> && indirectly_writable<_Out, iter_value_t<_In>&> && 266 indirectly_writable<_Out, const iter_value_t<_In>&> && indirectly_writable<_Out, iter_value_t<_In>&&> && 267 indirectly_writable<_Out, const iter_value_t<_In>&&> && copyable<iter_value_t<_In>> && 268 constructible_from<iter_value_t<_In>, iter_reference_t<_In>> && 269 assignable_from<iter_value_t<_In>&, iter_reference_t<_In>>; 270 271 // Note: indirectly_swappable is located in iter_swap.h to prevent a dependency cycle 272 // (both iter_swap and indirectly_swappable require indirectly_readable). 273 274 #endif // _LIBCPP_STD_VER >= 20 275 276 template <class _Tp> 277 using __has_random_access_iterator_category_or_concept _LIBCPP_NODEBUG 278 #if _LIBCPP_STD_VER >= 20 279 = integral_constant<bool, random_access_iterator<_Tp>>; 280 #else // _LIBCPP_STD_VER < 20 281 = __has_random_access_iterator_category<_Tp>; 282 #endif // _LIBCPP_STD_VER 283 284 _LIBCPP_END_NAMESPACE_STD 285 286 #endif // _LIBCPP___ITERATOR_CONCEPTS_H 287