| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___VARIANT_MONOSTATE_H |
| #define _LIBCPP___VARIANT_MONOSTATE_H |
| |
| #include <__config> |
| #include <__functional/hash.h> |
| #include <cstddef> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 14 |
| |
| struct _LIBCPP_TEMPLATE_VIS monostate {}; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<(monostate, monostate) noexcept { return false; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>(monostate, monostate) noexcept { return false; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<=(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>=(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator==(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator!=(monostate, monostate) noexcept { return false; } |
| |
| template <> |
| struct _LIBCPP_TEMPLATE_VIS hash<monostate> { |
| using argument_type = monostate; |
| using result_type = size_t; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| result_type operator()(const argument_type&) const _NOEXCEPT { |
| return 66740831; // return a fundamentally attractive random value. |
| } |
| }; |
| |
| #endif // _LIBCPP_STD_VER > 14 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___VARIANT_MONOSTATE_H |