176d0caaeSpatrick // -*- C++ -*- 276d0caaeSpatrick //===----------------------------------------------------------------------===// 376d0caaeSpatrick // 476d0caaeSpatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 576d0caaeSpatrick // See https://llvm.org/LICENSE.txt for license information. 676d0caaeSpatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 776d0caaeSpatrick // 876d0caaeSpatrick //===----------------------------------------------------------------------===// 976d0caaeSpatrick 1076d0caaeSpatrick #ifndef _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 1176d0caaeSpatrick #define _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 1276d0caaeSpatrick 13*4bdff4beSrobert #include <__concepts/arithmetic.h> 1476d0caaeSpatrick #include <__config> 15*4bdff4beSrobert #include <__type_traits/conditional.h> 16*4bdff4beSrobert #include <__type_traits/is_object.h> 17*4bdff4beSrobert #include <__type_traits/is_primary_template.h> 18*4bdff4beSrobert #include <__type_traits/make_signed.h> 19*4bdff4beSrobert #include <__type_traits/remove_cvref.h> 20*4bdff4beSrobert #include <__utility/declval.h> 21*4bdff4beSrobert #include <cstddef> 2276d0caaeSpatrick 2376d0caaeSpatrick #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 2476d0caaeSpatrick # pragma GCC system_header 2576d0caaeSpatrick #endif 2676d0caaeSpatrick 2776d0caaeSpatrick _LIBCPP_BEGIN_NAMESPACE_STD 2876d0caaeSpatrick 29*4bdff4beSrobert #if _LIBCPP_STD_VER > 17 3076d0caaeSpatrick 3176d0caaeSpatrick // [incrementable.traits] 3276d0caaeSpatrick template<class> struct incrementable_traits {}; 3376d0caaeSpatrick 3476d0caaeSpatrick template<class _Tp> 3576d0caaeSpatrick requires is_object_v<_Tp> 3676d0caaeSpatrick struct incrementable_traits<_Tp*> { 3776d0caaeSpatrick using difference_type = ptrdiff_t; 3876d0caaeSpatrick }; 3976d0caaeSpatrick 4076d0caaeSpatrick template<class _Ip> 4176d0caaeSpatrick struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {}; 4276d0caaeSpatrick 4376d0caaeSpatrick template<class _Tp> 4476d0caaeSpatrick concept __has_member_difference_type = requires { typename _Tp::difference_type; }; 4576d0caaeSpatrick 4676d0caaeSpatrick template<__has_member_difference_type _Tp> 4776d0caaeSpatrick struct incrementable_traits<_Tp> { 4876d0caaeSpatrick using difference_type = typename _Tp::difference_type; 4976d0caaeSpatrick }; 5076d0caaeSpatrick 5176d0caaeSpatrick template<class _Tp> 5276d0caaeSpatrick concept __has_integral_minus = 5376d0caaeSpatrick requires(const _Tp& __x, const _Tp& __y) { 5476d0caaeSpatrick { __x - __y } -> integral; 5576d0caaeSpatrick }; 5676d0caaeSpatrick 5776d0caaeSpatrick template<__has_integral_minus _Tp> 5876d0caaeSpatrick requires (!__has_member_difference_type<_Tp>) 5976d0caaeSpatrick struct incrementable_traits<_Tp> { 60*4bdff4beSrobert using difference_type = make_signed_t<decltype(std::declval<_Tp>() - std::declval<_Tp>())>; 6176d0caaeSpatrick }; 6276d0caaeSpatrick 6376d0caaeSpatrick template <class> 6476d0caaeSpatrick struct iterator_traits; 6576d0caaeSpatrick 6676d0caaeSpatrick // Let `RI` be `remove_cvref_t<I>`. The type `iter_difference_t<I>` denotes 6776d0caaeSpatrick // `incrementable_traits<RI>::difference_type` if `iterator_traits<RI>` names a specialization 6876d0caaeSpatrick // generated from the primary template, and `iterator_traits<RI>::difference_type` otherwise. 6976d0caaeSpatrick template <class _Ip> 7076d0caaeSpatrick using iter_difference_t = typename conditional_t<__is_primary_template<iterator_traits<remove_cvref_t<_Ip> > >::value, 7176d0caaeSpatrick incrementable_traits<remove_cvref_t<_Ip> >, 7276d0caaeSpatrick iterator_traits<remove_cvref_t<_Ip> > >::difference_type; 7376d0caaeSpatrick 74*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17 7576d0caaeSpatrick 7676d0caaeSpatrick _LIBCPP_END_NAMESPACE_STD 7776d0caaeSpatrick 7876d0caaeSpatrick #endif // _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H 79