We plan to add concepts for checking that iterators actually provide what they claim to. This is to avoid people thinking that these type traits actually check the iterator requirements in more detail. Reviewed By: ldionne, #libc Spies: Mordante, libcxx-commits, wenlei Differential Revision: https://reviews.llvm.org/D150801
85 lines
2.4 KiB
C++
85 lines
2.4 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 <__assert>
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#include <__config>
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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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#include <__iterator/iterator_traits.h>
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#include <__type_traits/enable_if.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_BEGIN_NAMESPACE_STD
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template <class _InputIter>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
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typename enable_if<__has_input_iterator_category<_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 || __has_bidirectional_iterator_category<_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 _LIBCPP_STD_VER >= 20
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// [range.iter.op.next]
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namespace ranges {
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namespace __next {
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struct __fn {
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template <input_or_output_iterator _Ip>
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_LIBCPP_HIDE_FROM_ABI
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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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_LIBCPP_HIDE_FROM_ABI
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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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_LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, _Sp __bound_sentinel) const {
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ranges::advance(__x, __bound_sentinel);
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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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_LIBCPP_HIDE_FROM_ABI constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp __bound_sentinel) const {
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ranges::advance(__x, __n, __bound_sentinel);
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return __x;
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}
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};
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} // namespace __next
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inline namespace __cpo {
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inline constexpr auto next = __next::__fn{};
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} // namespace __cpo
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} // namespace ranges
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#endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ITERATOR_NEXT_H
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