1*fe6060f1SDimitry Andric // -*- C++ -*- 2*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3*fe6060f1SDimitry Andric // 4*fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5*fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6*fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7*fe6060f1SDimitry Andric // 8*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9*fe6060f1SDimitry Andric 10*fe6060f1SDimitry Andric #ifndef _LIBCPP___VARIANT_MONOSTATE_H 11*fe6060f1SDimitry Andric #define _LIBCPP___VARIANT_MONOSTATE_H 12*fe6060f1SDimitry Andric 13*fe6060f1SDimitry Andric #include <__config> 14*fe6060f1SDimitry Andric #include <__functional/hash.h> 15*fe6060f1SDimitry Andric #include <cstddef> 16*fe6060f1SDimitry Andric 17*fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18*fe6060f1SDimitry Andric #pragma GCC system_header 19*fe6060f1SDimitry Andric #endif 20*fe6060f1SDimitry Andric 21*fe6060f1SDimitry Andric _LIBCPP_PUSH_MACROS 22*fe6060f1SDimitry Andric #include <__undef_macros> 23*fe6060f1SDimitry Andric 24*fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 25*fe6060f1SDimitry Andric 26*fe6060f1SDimitry Andric #if _LIBCPP_STD_VER > 14 27*fe6060f1SDimitry Andric 28*fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS monostate {}; 29*fe6060f1SDimitry Andric 30*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 31*fe6060f1SDimitry Andric constexpr bool operator<(monostate, monostate) noexcept { return false; } 32*fe6060f1SDimitry Andric 33*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 34*fe6060f1SDimitry Andric constexpr bool operator>(monostate, monostate) noexcept { return false; } 35*fe6060f1SDimitry Andric 36*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 37*fe6060f1SDimitry Andric constexpr bool operator<=(monostate, monostate) noexcept { return true; } 38*fe6060f1SDimitry Andric 39*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 40*fe6060f1SDimitry Andric constexpr bool operator>=(monostate, monostate) noexcept { return true; } 41*fe6060f1SDimitry Andric 42*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 43*fe6060f1SDimitry Andric constexpr bool operator==(monostate, monostate) noexcept { return true; } 44*fe6060f1SDimitry Andric 45*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 46*fe6060f1SDimitry Andric constexpr bool operator!=(monostate, monostate) noexcept { return false; } 47*fe6060f1SDimitry Andric 48*fe6060f1SDimitry Andric template <> 49*fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS hash<monostate> { 50*fe6060f1SDimitry Andric using argument_type = monostate; 51*fe6060f1SDimitry Andric using result_type = size_t; 52*fe6060f1SDimitry Andric 53*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY 54*fe6060f1SDimitry Andric result_type operator()(const argument_type&) const _NOEXCEPT { 55*fe6060f1SDimitry Andric return 66740831; // return a fundamentally attractive random value. 56*fe6060f1SDimitry Andric } 57*fe6060f1SDimitry Andric }; 58*fe6060f1SDimitry Andric 59*fe6060f1SDimitry Andric #endif // _LIBCPP_STD_VER > 14 60*fe6060f1SDimitry Andric 61*fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 62*fe6060f1SDimitry Andric 63*fe6060f1SDimitry Andric _LIBCPP_POP_MACROS 64*fe6060f1SDimitry Andric 65*fe6060f1SDimitry Andric #endif // _LIBCPP___VARIANT_MONOSTATE_H 66