// -*- 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
//
//===----------------------------------------------------------------------===//
//==============================================================================
// NOTICE: This file has been modified by Green Hills Software, Inc.  Such
// modifications are subject to copyright by Green Hills Software, Inc.  See the
// "Green Hills Software Modifications" section in the LICENSE.txt included with
// this distribution for more information.
//==============================================================================

#ifndef _LIBCPP___VARIANT_MONOSTATE_H
#define _LIBCPP___VARIANT_MONOSTATE_H

#include <__compare/ordering.h>
#include <__config>
#include <__functional/hash.h>
#include <cstddef>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

#if defined(__ghs__)
  #pragma ghs start_cxx_lib_header
  #pragma ghs startdata
  #if defined(__ghs_max_pack_value)
    #pragma pack (push, __ghs_max_pack_value)
  #endif
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER > 14

struct _LIBCPP_TEMPLATE_VIS monostate {};

_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(monostate, monostate) noexcept { return true; }

#  if _LIBCPP_STD_VER > 17

_LIBCPP_HIDE_FROM_ABI constexpr strong_ordering operator<=>(monostate, monostate) noexcept {
  return strong_ordering::equal;
}

#  else // _LIBCPP_STD_VER > 17

_LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(monostate, monostate) noexcept { return false; }

_LIBCPP_HIDE_FROM_ABI constexpr bool operator<(monostate, monostate) noexcept { return false; }

_LIBCPP_HIDE_FROM_ABI constexpr bool operator>(monostate, monostate) noexcept { return false; }

_LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(monostate, monostate) noexcept { return true; }

_LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(monostate, monostate) noexcept { return true; }

#  endif // _LIBCPP_STD_VER > 17

template <>
struct _LIBCPP_TEMPLATE_VIS hash<monostate> {
  using argument_type = monostate;
  using result_type = size_t;

  inline _LIBCPP_HIDE_FROM_ABI 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

#if defined(__ghs__)
  #if defined(__ghs_max_pack_value)
    #pragma pack(pop)
  #endif
  #pragma ghs enddata
  #pragma ghs end_cxx_lib_header
#endif

#endif // _LIBCPP___VARIANT_MONOSTATE_H