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