forked from OSchip/llvm-project
82 lines
2.4 KiB
C++
82 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___RANGES_SINGLE_VIEW_H
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#define _LIBCPP___RANGES_SINGLE_VIEW_H
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#include <__config>
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#include <__ranges/copyable_box.h>
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#include <__ranges/view_interface.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 <concepts>
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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 !defined(_LIBCPP_HAS_NO_CONCEPTS)
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namespace ranges {
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template<copy_constructible _Tp>
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requires is_object_v<_Tp>
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class single_view : public view_interface<single_view<_Tp>> {
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__copyable_box<_Tp> __value_;
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public:
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_LIBCPP_HIDE_FROM_ABI
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single_view() requires default_initializable<_Tp> = default;
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_LIBCPP_HIDE_FROM_ABI
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constexpr explicit single_view(const _Tp& __t) : __value_(in_place, __t) {}
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_LIBCPP_HIDE_FROM_ABI
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constexpr explicit single_view(_Tp&& __t) : __value_(in_place, _VSTD::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
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constexpr explicit single_view(in_place_t, _Args&&... __args)
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: __value_{in_place, _VSTD::forward<_Args>(__args)...} {}
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Tp* begin() noexcept { return data(); }
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_LIBCPP_HIDE_FROM_ABI
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constexpr const _Tp* begin() const noexcept { return data(); }
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Tp* end() noexcept { return data() + 1; }
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_LIBCPP_HIDE_FROM_ABI
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constexpr const _Tp* end() const noexcept { return data() + 1; }
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_LIBCPP_HIDE_FROM_ABI
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static constexpr size_t size() noexcept { return 1; }
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Tp* data() noexcept { return __value_.operator->(); }
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_LIBCPP_HIDE_FROM_ABI
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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 ranges
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#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANGES_SINGLE_VIEW_H
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