forked from OSchip/llvm-project
82 lines
3.0 KiB
C++
82 lines
3.0 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___RANGES_COUNTED_H
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#define _LIBCPP___RANGES_COUNTED_H
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#include <__concepts/convertible_to.h>
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__iterator/counted_iterator.h>
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#include <__iterator/default_sentinel.h>
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#include <__iterator/incrementable_traits.h>
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#include <__iterator/iterator_traits.h>
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#include <__memory/pointer_traits.h>
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#include <__ranges/subrange.h>
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#include <__utility/forward.h>
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#include <__utility/move.h>
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#include <span>
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#include <type_traits>
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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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#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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namespace ranges::views {
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namespace __counted {
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struct __fn {
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template<contiguous_iterator _It>
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_LIBCPP_HIDE_FROM_ABI
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static constexpr auto __go(_It __it, iter_difference_t<_It> __count)
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noexcept(noexcept(span(std::to_address(__it), static_cast<size_t>(__count))))
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// Deliberately omit return-type SFINAE, because to_address is not SFINAE-friendly
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{ return span(std::to_address(__it), static_cast<size_t>(__count)); }
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template<random_access_iterator _It>
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_LIBCPP_HIDE_FROM_ABI
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static constexpr auto __go(_It __it, iter_difference_t<_It> __count)
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noexcept(noexcept(subrange(__it, __it + __count)))
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-> decltype( subrange(__it, __it + __count))
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{ return subrange(__it, __it + __count); }
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template<class _It>
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_LIBCPP_HIDE_FROM_ABI
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static constexpr auto __go(_It __it, iter_difference_t<_It> __count)
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noexcept(noexcept(subrange(counted_iterator(std::move(__it), __count), default_sentinel)))
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-> decltype( subrange(counted_iterator(std::move(__it), __count), default_sentinel))
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{ return subrange(counted_iterator(std::move(__it), __count), default_sentinel); }
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template<class _It, convertible_to<iter_difference_t<_It>> _Diff>
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requires input_or_output_iterator<decay_t<_It>>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI
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constexpr auto operator()(_It&& __it, _Diff&& __count) const
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noexcept(noexcept(__go(std::forward<_It>(__it), std::forward<_Diff>(__count))))
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-> decltype( __go(std::forward<_It>(__it), std::forward<_Diff>(__count)))
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{ return __go(std::forward<_It>(__it), std::forward<_Diff>(__count)); }
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};
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} // namespace __counted
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inline namespace __cpo {
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inline constexpr auto counted = __counted::__fn{};
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} // namespace __cpo
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} // namespace ranges::views
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#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANGES_COUNTED_H
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