mirror of
https://github.com/jart/cosmopolitan.git
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89 lines
2.9 KiB
C++
89 lines
2.9 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 <__type_traits/decay.h>
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#include <__utility/forward.h>
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#include <__utility/move.h>
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#include <cstddef>
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#include <span>
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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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#if _LIBCPP_STD_VER >= 20
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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 static constexpr auto
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__go(_It __it,
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iter_difference_t<_It> __count) 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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{
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return span(std::to_address(__it), static_cast<size_t>(__count));
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}
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template <random_access_iterator _It>
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_It __it, iter_difference_t<_It> __count) noexcept(
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noexcept(subrange(__it, __it + __count))) -> decltype(subrange(__it, __it + __count)) {
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return subrange(__it, __it + __count);
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}
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template <class _It>
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_It __it, iter_difference_t<_It> __count) noexcept(
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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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}
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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 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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};
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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 >= 20
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___RANGES_COUNTED_H
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