// Copyright (C) 2015-2026 The Neo Project.
//
// ReferenceEqualityComparer.cs file belongs to the neo project and is free
// software distributed under the MIT software license, see the
// accompanying file LICENSE in the main directory of the
// repository or http://www.opensource.org/licenses/mit-license.php
// for more details.
//
// Redistribution and use in source and binary forms with or without
// modifications are permitted.

using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace Neo.VM;

#if !NET5_0_OR_GREATER
// https://github.dev/dotnet/runtime/blob/main/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/ReferenceEqualityComparer.cs
public sealed class ReferenceEqualityComparer : IEqualityComparer<object?>, System.Collections.IEqualityComparer
{
    private ReferenceEqualityComparer() { }

    public static ReferenceEqualityComparer Instance { get; } = new ReferenceEqualityComparer();

    public new bool Equals(object? x, object? y) => ReferenceEquals(x, y);

    public int GetHashCode(object? obj) => RuntimeHelpers.GetHashCode(obj!);
}
#endif
