80 lines
2.3 KiB
C++
80 lines
2.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___ITERATOR_NEXT_H
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#define _LIBCPP___ITERATOR_NEXT_H
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#include <__config>
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#include <__function_like.h>
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#include <__iterator/advance.h>
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#include <__iterator/concepts.h>
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#include <__iterator/incrementable_traits.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _InputIter>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
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next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
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_LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
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"Attempt to next(it, n) with negative n on a non-bidirectional iterator");
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_VSTD::advance(__x, __n);
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return __x;
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}
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#if !defined(_LIBCPP_HAS_NO_RANGES)
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namespace ranges {
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struct __next_fn final : private __function_like {
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constexpr explicit __next_fn(__tag __x) noexcept : __function_like(__x) {}
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template <input_or_output_iterator _Ip>
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constexpr _Ip operator()(_Ip __x) const {
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++__x;
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return __x;
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}
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template <input_or_output_iterator _Ip>
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constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
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ranges::advance(__x, __n);
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return __x;
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}
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template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
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constexpr _Ip operator()(_Ip __x, _Sp __bound) const {
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ranges::advance(__x, __bound);
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return __x;
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}
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template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
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constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound) const {
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ranges::advance(__x, __n, __bound);
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return __x;
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}
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};
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inline constexpr auto next = __next_fn(__function_like::__tag());
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} // namespace ranges
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#endif // !defined(_LIBCPP_HAS_NO_RANGES)
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ITERATOR_PRIMITIVES_H
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