1e78f53d1SNikolas Klauser // -*- C++ -*- 2e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===// 3e78f53d1SNikolas Klauser // 4e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information. 6e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7e78f53d1SNikolas Klauser // 8e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===// 9e78f53d1SNikolas Klauser 10*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___ITERATOR_INCREMENTABLE_TRAITS_H 11*ce777190SNikolas Klauser #define _LIBCPP___CXX03___ITERATOR_INCREMENTABLE_TRAITS_H 12e78f53d1SNikolas Klauser 1373fbae83SNikolas Klauser #include <__cxx03/__concepts/arithmetic.h> 1473fbae83SNikolas Klauser #include <__cxx03/__config> 1573fbae83SNikolas Klauser #include <__cxx03/__type_traits/conditional.h> 1673fbae83SNikolas Klauser #include <__cxx03/__type_traits/is_object.h> 1773fbae83SNikolas Klauser #include <__cxx03/__type_traits/is_primary_template.h> 1873fbae83SNikolas Klauser #include <__cxx03/__type_traits/make_signed.h> 1973fbae83SNikolas Klauser #include <__cxx03/__type_traits/remove_cvref.h> 2073fbae83SNikolas Klauser #include <__cxx03/__utility/declval.h> 2173fbae83SNikolas Klauser #include <__cxx03/cstddef> 22e78f53d1SNikolas Klauser 23e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24e78f53d1SNikolas Klauser # pragma GCC system_header 25e78f53d1SNikolas Klauser #endif 26e78f53d1SNikolas Klauser 27e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD 28e78f53d1SNikolas Klauser 29e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20 30e78f53d1SNikolas Klauser 31e78f53d1SNikolas Klauser // [incrementable.traits] 32e78f53d1SNikolas Klauser template <class> 33e78f53d1SNikolas Klauser struct incrementable_traits {}; 34e78f53d1SNikolas Klauser 35e78f53d1SNikolas Klauser template <class _Tp> 36e78f53d1SNikolas Klauser requires is_object_v<_Tp> 37e78f53d1SNikolas Klauser struct incrementable_traits<_Tp*> { 38e78f53d1SNikolas Klauser using difference_type = ptrdiff_t; 39e78f53d1SNikolas Klauser }; 40e78f53d1SNikolas Klauser 41e78f53d1SNikolas Klauser template <class _Ip> 42e78f53d1SNikolas Klauser struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {}; 43e78f53d1SNikolas Klauser 44e78f53d1SNikolas Klauser template <class _Tp> 45e78f53d1SNikolas Klauser concept __has_member_difference_type = requires { typename _Tp::difference_type; }; 46e78f53d1SNikolas Klauser 47e78f53d1SNikolas Klauser template <__has_member_difference_type _Tp> 48e78f53d1SNikolas Klauser struct incrementable_traits<_Tp> { 49e78f53d1SNikolas Klauser using difference_type = typename _Tp::difference_type; 50e78f53d1SNikolas Klauser }; 51e78f53d1SNikolas Klauser 52e78f53d1SNikolas Klauser template <class _Tp> 53e78f53d1SNikolas Klauser concept __has_integral_minus = requires(const _Tp& __x, const _Tp& __y) { 54e78f53d1SNikolas Klauser { __x - __y } -> integral; 55e78f53d1SNikolas Klauser }; 56e78f53d1SNikolas Klauser 57e78f53d1SNikolas Klauser template <__has_integral_minus _Tp> 58e78f53d1SNikolas Klauser requires(!__has_member_difference_type<_Tp>) 59e78f53d1SNikolas Klauser struct incrementable_traits<_Tp> { 60e78f53d1SNikolas Klauser using difference_type = make_signed_t<decltype(std::declval<_Tp>() - std::declval<_Tp>())>; 61e78f53d1SNikolas Klauser }; 62e78f53d1SNikolas Klauser 63e78f53d1SNikolas Klauser template <class> 64e78f53d1SNikolas Klauser struct iterator_traits; 65e78f53d1SNikolas Klauser 66e78f53d1SNikolas Klauser // Let `RI` be `remove_cvref_t<I>`. The type `iter_difference_t<I>` denotes 67e78f53d1SNikolas Klauser // `incrementable_traits<RI>::difference_type` if `iterator_traits<RI>` names a specialization 68e78f53d1SNikolas Klauser // generated from the primary template, and `iterator_traits<RI>::difference_type` otherwise. 69e78f53d1SNikolas Klauser template <class _Ip> 70e78f53d1SNikolas Klauser using iter_difference_t = 71e78f53d1SNikolas Klauser typename conditional_t<__is_primary_template<iterator_traits<remove_cvref_t<_Ip> > >::value, 72e78f53d1SNikolas Klauser incrementable_traits<remove_cvref_t<_Ip> >, 73e78f53d1SNikolas Klauser iterator_traits<remove_cvref_t<_Ip> > >::difference_type; 74e78f53d1SNikolas Klauser 75e78f53d1SNikolas Klauser #endif // _LIBCPP_STD_VER >= 20 76e78f53d1SNikolas Klauser 77e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD 78e78f53d1SNikolas Klauser 79*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___ITERATOR_INCREMENTABLE_TRAITS_H 80