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_NEXT_H 11fe6060f1SDimitry Andric #define _LIBCPP___ITERATOR_NEXT_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__config> 14fe6060f1SDimitry Andric #include <__debug> 15fe6060f1SDimitry Andric #include <__function_like.h> 16fe6060f1SDimitry Andric #include <__iterator/advance.h> 17fe6060f1SDimitry Andric #include <__iterator/concepts.h> 18fe6060f1SDimitry Andric #include <__iterator/incrementable_traits.h> 19fe6060f1SDimitry Andric #include <__iterator/iterator_traits.h> 20fe6060f1SDimitry Andric #include <type_traits> 21fe6060f1SDimitry Andric 22fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23fe6060f1SDimitry Andric #pragma GCC system_header 24fe6060f1SDimitry Andric #endif 25fe6060f1SDimitry Andric 26fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 27fe6060f1SDimitry Andric 28fe6060f1SDimitry Andric template <class _InputIter> 29fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 30fe6060f1SDimitry Andric typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type 31fe6060f1SDimitry Andric next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) { 32fe6060f1SDimitry Andric _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value, 33fe6060f1SDimitry Andric "Attempt to next(it, n) with negative n on a non-bidirectional iterator"); 34fe6060f1SDimitry Andric 35fe6060f1SDimitry Andric _VSTD::advance(__x, __n); 36fe6060f1SDimitry Andric return __x; 37fe6060f1SDimitry Andric } 38fe6060f1SDimitry Andric 39fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_RANGES) 40fe6060f1SDimitry Andric 41fe6060f1SDimitry Andric namespace ranges { 42*0eae32dcSDimitry Andric // TODO(varconst): rename `__next_fn` to `__fn`. 43fe6060f1SDimitry Andric struct __next_fn final : private __function_like { 44fe6060f1SDimitry Andric _LIBCPP_HIDE_FROM_ABI 45fe6060f1SDimitry Andric constexpr explicit __next_fn(__tag __x) noexcept : __function_like(__x) {} 46fe6060f1SDimitry Andric 47fe6060f1SDimitry Andric template <input_or_output_iterator _Ip> 48fe6060f1SDimitry Andric _LIBCPP_HIDE_FROM_ABI 49fe6060f1SDimitry Andric constexpr _Ip operator()(_Ip __x) const { 50fe6060f1SDimitry Andric ++__x; 51fe6060f1SDimitry Andric return __x; 52fe6060f1SDimitry Andric } 53fe6060f1SDimitry Andric 54fe6060f1SDimitry Andric template <input_or_output_iterator _Ip> 55fe6060f1SDimitry Andric _LIBCPP_HIDE_FROM_ABI 56fe6060f1SDimitry Andric constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const { 57fe6060f1SDimitry Andric ranges::advance(__x, __n); 58fe6060f1SDimitry Andric return __x; 59fe6060f1SDimitry Andric } 60fe6060f1SDimitry Andric 61fe6060f1SDimitry Andric template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp> 62fe6060f1SDimitry Andric _LIBCPP_HIDE_FROM_ABI 63fe6060f1SDimitry Andric constexpr _Ip operator()(_Ip __x, _Sp __bound) const { 64fe6060f1SDimitry Andric ranges::advance(__x, __bound); 65fe6060f1SDimitry Andric return __x; 66fe6060f1SDimitry Andric } 67fe6060f1SDimitry Andric 68fe6060f1SDimitry Andric template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp> 69fe6060f1SDimitry Andric _LIBCPP_HIDE_FROM_ABI 70fe6060f1SDimitry Andric constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound) const { 71fe6060f1SDimitry Andric ranges::advance(__x, __n, __bound); 72fe6060f1SDimitry Andric return __x; 73fe6060f1SDimitry Andric } 74fe6060f1SDimitry Andric }; 75fe6060f1SDimitry Andric 76fe6060f1SDimitry Andric inline constexpr auto next = __next_fn(__function_like::__tag()); 77fe6060f1SDimitry Andric } // namespace ranges 78fe6060f1SDimitry Andric 79fe6060f1SDimitry Andric #endif // !defined(_LIBCPP_HAS_NO_RANGES) 80fe6060f1SDimitry Andric 81fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 82fe6060f1SDimitry Andric 83*0eae32dcSDimitry Andric #endif // _LIBCPP___ITERATOR_NEXT_H 84