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_NEXT_H 11 #define _LIBCPP___ITERATOR_NEXT_H 12 13 #include <__config> 14 #include <__iterator/advance.h> 15 #include <__iterator/concepts.h> 16 #include <__iterator/incrementable_traits.h> 17 #include <__iterator/iterator_traits.h> 18 #include <__type_traits/enable_if.h> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0> 27 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _InputIter 28 next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) { 29 std::advance(__x, __n); 30 return __x; 31 } 32 33 #if _LIBCPP_STD_VER >= 20 34 35 // [range.iter.op.next] 36 37 namespace ranges { 38 struct __next { 39 template <input_or_output_iterator _Ip> 40 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x) const { 41 ++__x; 42 return __x; 43 } 44 45 template <input_or_output_iterator _Ip> 46 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const { 47 ranges::advance(__x, __n); 48 return __x; 49 } 50 51 template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp> 52 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, _Sp __bound_sentinel) const { 53 ranges::advance(__x, __bound_sentinel); 54 return __x; 55 } 56 57 template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp> 58 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip 59 operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound_sentinel) const { 60 ranges::advance(__x, __n, __bound_sentinel); 61 return __x; 62 } 63 }; 64 65 inline namespace __cpo { 66 inline constexpr auto next = __next{}; 67 } // namespace __cpo 68 } // namespace ranges 69 70 #endif // _LIBCPP_STD_VER >= 20 71 72 _LIBCPP_END_NAMESPACE_STD 73 74 #endif // _LIBCPP___ITERATOR_NEXT_H 75