xref: /openbsd-src/gnu/llvm/libcxx/include/__iterator/next.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
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_NEXT_H
1176d0caaeSpatrick #define _LIBCPP___ITERATOR_NEXT_H
1276d0caaeSpatrick 
13*4bdff4beSrobert #include <__assert>
1476d0caaeSpatrick #include <__config>
1576d0caaeSpatrick #include <__iterator/advance.h>
1676d0caaeSpatrick #include <__iterator/concepts.h>
1776d0caaeSpatrick #include <__iterator/incrementable_traits.h>
1876d0caaeSpatrick #include <__iterator/iterator_traits.h>
19*4bdff4beSrobert #include <__type_traits/enable_if.h>
2076d0caaeSpatrick 
2176d0caaeSpatrick #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
2276d0caaeSpatrick #  pragma GCC system_header
2376d0caaeSpatrick #endif
2476d0caaeSpatrick 
2576d0caaeSpatrick _LIBCPP_BEGIN_NAMESPACE_STD
2676d0caaeSpatrick 
2776d0caaeSpatrick template <class _InputIter>
28*4bdff4beSrobert inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
2976d0caaeSpatrick     typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
3076d0caaeSpatrick     next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
3176d0caaeSpatrick   _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
3276d0caaeSpatrick                  "Attempt to next(it, n) with negative n on a non-bidirectional iterator");
3376d0caaeSpatrick 
3476d0caaeSpatrick   _VSTD::advance(__x, __n);
3576d0caaeSpatrick   return __x;
3676d0caaeSpatrick }
3776d0caaeSpatrick 
38*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
39*4bdff4beSrobert 
40*4bdff4beSrobert // [range.iter.op.next]
4176d0caaeSpatrick 
4276d0caaeSpatrick namespace ranges {
43*4bdff4beSrobert namespace __next {
4476d0caaeSpatrick 
45*4bdff4beSrobert struct __fn {
4676d0caaeSpatrick   template <input_or_output_iterator _Ip>
4776d0caaeSpatrick   _LIBCPP_HIDE_FROM_ABI
operator__fn4876d0caaeSpatrick   constexpr _Ip operator()(_Ip __x) const {
4976d0caaeSpatrick     ++__x;
5076d0caaeSpatrick     return __x;
5176d0caaeSpatrick   }
5276d0caaeSpatrick 
5376d0caaeSpatrick   template <input_or_output_iterator _Ip>
5476d0caaeSpatrick   _LIBCPP_HIDE_FROM_ABI
operator__fn5576d0caaeSpatrick   constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
5676d0caaeSpatrick     ranges::advance(__x, __n);
5776d0caaeSpatrick     return __x;
5876d0caaeSpatrick   }
5976d0caaeSpatrick 
6076d0caaeSpatrick   template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
operator__fn61*4bdff4beSrobert   _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, _Sp __bound_sentinel) const {
62*4bdff4beSrobert     ranges::advance(__x, __bound_sentinel);
6376d0caaeSpatrick     return __x;
6476d0caaeSpatrick   }
6576d0caaeSpatrick 
6676d0caaeSpatrick   template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
operator__fn67*4bdff4beSrobert   _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound_sentinel) const {
68*4bdff4beSrobert     ranges::advance(__x, __n, __bound_sentinel);
6976d0caaeSpatrick     return __x;
7076d0caaeSpatrick   }
7176d0caaeSpatrick };
7276d0caaeSpatrick 
73*4bdff4beSrobert } // namespace __next
74*4bdff4beSrobert 
75*4bdff4beSrobert inline namespace __cpo {
76*4bdff4beSrobert   inline constexpr auto next = __next::__fn{};
77*4bdff4beSrobert } // namespace __cpo
7876d0caaeSpatrick } // namespace ranges
7976d0caaeSpatrick 
80*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17
8176d0caaeSpatrick 
8276d0caaeSpatrick _LIBCPP_END_NAMESPACE_STD
8376d0caaeSpatrick 
84*4bdff4beSrobert #endif // _LIBCPP___ITERATOR_NEXT_H
85