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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ITERATOR_NEXT_H
#define _LIBCPP___ITERATOR_NEXT_H
#include <__assert>
#include <__config>
#include <__iterator/advance.h>
#include <__iterator/concepts.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/iterator_traits.h>
#include <__type_traits/enable_if.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _InputIter
next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
// Calling `advance` with a negative value on a non-bidirectional iterator is a no-op in the current implementation.
// Note that this check duplicates the similar check in `std::advance`.
_LIBCPP_ASSERT_PEDANTIC(__n >= 0 || __has_bidirectional_iterator_category<_InputIter>::value,
"Attempt to next(it, n) with negative n on a non-bidirectional iterator");
std::advance(__x, __n);
return __x;
}
#if _LIBCPP_STD_VER >= 20
// [range.iter.op.next]
namespace ranges {
struct __next {
template <input_or_output_iterator _Ip>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x) const {
++__x;
return __x;
}
template <input_or_output_iterator _Ip>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
ranges::advance(__x, __n);
return __x;
}
template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, _Sp __bound_sentinel) const {
ranges::advance(__x, __bound_sentinel);
return __x;
}
template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound_sentinel) const {
ranges::advance(__x, __n, __bound_sentinel);
return __x;
}
};
inline namespace __cpo {
inline constexpr auto next = __next{};
} // namespace __cpo
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ITERATOR_NEXT_H
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