1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 11fe6060f1SDimitry Andric #define _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 12fe6060f1SDimitry Andric 13bdd1243dSDimitry Andric #include <__concepts/arithmetic.h> 14fe6060f1SDimitry Andric #include <__config> 15bdd1243dSDimitry Andric #include <__type_traits/conditional.h> 16bdd1243dSDimitry Andric #include <__type_traits/is_object.h> 17972a253aSDimitry Andric #include <__type_traits/is_primary_template.h> 18bdd1243dSDimitry Andric #include <__type_traits/make_signed.h> 19bdd1243dSDimitry Andric #include <__type_traits/remove_cvref.h> 20bdd1243dSDimitry Andric #include <__utility/declval.h> 2161cfbce3SDimitry Andric #include <cstddef> 22fe6060f1SDimitry Andric 23fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24fe6060f1SDimitry Andric # pragma GCC system_header 25fe6060f1SDimitry Andric #endif 26fe6060f1SDimitry Andric 27fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 28fe6060f1SDimitry Andric 2906c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 30fe6060f1SDimitry Andric 31fe6060f1SDimitry Andric // [incrementable.traits] 32*cb14a3feSDimitry Andric template <class> 33*cb14a3feSDimitry Andric struct incrementable_traits {}; 34fe6060f1SDimitry Andric 35fe6060f1SDimitry Andric template <class _Tp> 36fe6060f1SDimitry Andric requires is_object_v<_Tp> 37fe6060f1SDimitry Andric struct incrementable_traits<_Tp*> { 38fe6060f1SDimitry Andric using difference_type = ptrdiff_t; 39fe6060f1SDimitry Andric }; 40fe6060f1SDimitry Andric 41fe6060f1SDimitry Andric template <class _Ip> 42fe6060f1SDimitry Andric struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {}; 43fe6060f1SDimitry Andric 44fe6060f1SDimitry Andric template <class _Tp> 45fe6060f1SDimitry Andric concept __has_member_difference_type = requires { typename _Tp::difference_type; }; 46fe6060f1SDimitry Andric 47fe6060f1SDimitry Andric template <__has_member_difference_type _Tp> 48fe6060f1SDimitry Andric struct incrementable_traits<_Tp> { 49fe6060f1SDimitry Andric using difference_type = typename _Tp::difference_type; 50fe6060f1SDimitry Andric }; 51fe6060f1SDimitry Andric 52fe6060f1SDimitry Andric template <class _Tp> 53*cb14a3feSDimitry Andric concept __has_integral_minus = requires(const _Tp& __x, const _Tp& __y) { 54fe6060f1SDimitry Andric { __x - __y } -> integral; 55fe6060f1SDimitry Andric }; 56fe6060f1SDimitry Andric 57fe6060f1SDimitry Andric template <__has_integral_minus _Tp> 58fe6060f1SDimitry Andric requires(!__has_member_difference_type<_Tp>) 59fe6060f1SDimitry Andric struct incrementable_traits<_Tp> { 60bdd1243dSDimitry Andric using difference_type = make_signed_t<decltype(std::declval<_Tp>() - std::declval<_Tp>())>; 61fe6060f1SDimitry Andric }; 62fe6060f1SDimitry Andric 63fe6060f1SDimitry Andric template <class> 64fe6060f1SDimitry Andric struct iterator_traits; 65fe6060f1SDimitry Andric 66fe6060f1SDimitry Andric // Let `RI` be `remove_cvref_t<I>`. The type `iter_difference_t<I>` denotes 67fe6060f1SDimitry Andric // `incrementable_traits<RI>::difference_type` if `iterator_traits<RI>` names a specialization 68fe6060f1SDimitry Andric // generated from the primary template, and `iterator_traits<RI>::difference_type` otherwise. 69fe6060f1SDimitry Andric template <class _Ip> 70*cb14a3feSDimitry Andric using iter_difference_t = 71*cb14a3feSDimitry Andric typename conditional_t<__is_primary_template<iterator_traits<remove_cvref_t<_Ip> > >::value, 72fe6060f1SDimitry Andric incrementable_traits<remove_cvref_t<_Ip> >, 73fe6060f1SDimitry Andric iterator_traits<remove_cvref_t<_Ip> > >::difference_type; 74fe6060f1SDimitry Andric 7506c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 76fe6060f1SDimitry Andric 77fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 78fe6060f1SDimitry Andric 79fe6060f1SDimitry Andric #endif // _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 80