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51 lines
1.4 KiB
C++
51 lines
1.4 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_ENABLE_VIEW_H
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#define _LIBCPP___RANGES_ENABLE_VIEW_H
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#include <__concepts/derived_from.h>
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#include <__concepts/same_as.h>
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#include <__config>
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#include <__type_traits/is_class.h>
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#include <__type_traits/is_convertible.h>
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#include <__type_traits/remove_cv.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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#if _LIBCPP_STD_VER >= 20
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namespace ranges {
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struct view_base {};
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template <class _Derived>
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requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
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class view_interface;
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template <class _Op, class _Yp>
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requires is_convertible_v<_Op*, view_interface<_Yp>*>
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void __is_derived_from_view_interface(const _Op*, const view_interface<_Yp>*);
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template <class _Tp>
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inline constexpr bool enable_view = derived_from<_Tp, view_base> || requires {
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ranges::__is_derived_from_view_interface((_Tp*)nullptr, (_Tp*)nullptr);
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};
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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___RANGES_ENABLE_VIEW_H
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