mirror of
https://github.com/jart/cosmopolitan.git
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111 lines
3.4 KiB
C++
111 lines
3.4 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___RANGES_SINGLE_VIEW_H
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#define _LIBCPP___RANGES_SINGLE_VIEW_H
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#include <__concepts/constructible.h>
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#include <__config>
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#include <__ranges/movable_box.h>
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#include <__ranges/range_adaptor.h>
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#include <__ranges/view_interface.h>
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#include <__type_traits/decay.h>
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#include <__type_traits/is_object.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
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#include <__utility/move.h>
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#include <cstddef>
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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 {
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# if _LIBCPP_STD_VER >= 23
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template <move_constructible _Tp>
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# else
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template <copy_constructible _Tp>
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# endif
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requires is_object_v<_Tp>
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class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS single_view : public view_interface<single_view<_Tp>> {
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_LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Tp> __value_;
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public:
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_LIBCPP_HIDE_FROM_ABI single_view()
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requires default_initializable<_Tp>
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= default;
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_LIBCPP_HIDE_FROM_ABI constexpr explicit single_view(const _Tp& __t)
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# if _LIBCPP_STD_VER >= 23
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requires copy_constructible<_Tp>
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# endif
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: __value_(in_place, __t) {
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}
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_LIBCPP_HIDE_FROM_ABI constexpr explicit single_view(_Tp&& __t) : __value_(in_place, std::move(__t)) {}
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template <class... _Args>
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requires constructible_from<_Tp, _Args...>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit single_view(in_place_t, _Args&&... __args)
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: __value_{in_place, std::forward<_Args>(__args)...} {}
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_LIBCPP_HIDE_FROM_ABI constexpr _Tp* begin() noexcept { return data(); }
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_LIBCPP_HIDE_FROM_ABI constexpr const _Tp* begin() const noexcept { return data(); }
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_LIBCPP_HIDE_FROM_ABI constexpr _Tp* end() noexcept { return data() + 1; }
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_LIBCPP_HIDE_FROM_ABI constexpr const _Tp* end() const noexcept { return data() + 1; }
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_LIBCPP_HIDE_FROM_ABI static constexpr bool empty() noexcept { return false; }
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_LIBCPP_HIDE_FROM_ABI static constexpr size_t size() noexcept { return 1; }
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_LIBCPP_HIDE_FROM_ABI constexpr _Tp* data() noexcept { return __value_.operator->(); }
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_LIBCPP_HIDE_FROM_ABI constexpr const _Tp* data() const noexcept { return __value_.operator->(); }
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};
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template <class _Tp>
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single_view(_Tp) -> single_view<_Tp>;
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namespace views {
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namespace __single_view {
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struct __fn : __range_adaptor_closure<__fn> {
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template <class _Range>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const
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noexcept(noexcept(single_view<decay_t<_Range&&>>(std::forward<_Range>(__range))))
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-> decltype(single_view<decay_t<_Range&&>>(std::forward<_Range>(__range))) {
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return single_view<decay_t<_Range&&>>(std::forward<_Range>(__range));
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}
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};
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} // namespace __single_view
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inline namespace __cpo {
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inline constexpr auto single = __single_view::__fn{};
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} // namespace __cpo
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} // namespace views
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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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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___RANGES_SINGLE_VIEW_H
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