7ded638ea3
Certain headers require `optional<T&>`, so it may be beneficial to split out `optional<T>` and `optional<T&>`. This can allow consumers to only bring in the `optional` flavour it needs.. - Parcel out the respective pieces into their own header. - Certain sources rely on transitive includes brought in by `<optional>`, so they're kept there for now, and only tests have been fixed. --------- Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
47 lines
1.4 KiB
C++
47 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___OPTIONAL_HASH_H
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#define _LIBCPP___OPTIONAL_HASH_H
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#include <__config>
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#include <__cstddef/size_t.h>
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#include <__functional/hash.h>
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#include <__fwd/optional.h>
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#include <__type_traits/remove_const.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_PUSH_MACROS
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#include <__undef_macros>
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#if _LIBCPP_STD_VER >= 17
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp>
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struct hash< __enable_hash_helper<optional<_Tp>, remove_const_t<_Tp>> > {
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# if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
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_LIBCPP_DEPRECATED_IN_CXX17 typedef optional<_Tp> argument_type;
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_LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
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# endif
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI size_t operator()(const optional<_Tp>& __opt) const {
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return static_cast<bool>(__opt) ? hash<remove_const_t<_Tp>>()(*__opt) : 0;
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}
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};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 17
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___OPTIONAL_HASH_H
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