HashSetEqualityComparer.cs

Go to the documentation of this file.

using System.Diagnostics.CodeAnalysis;
 
namespace System.Collections.Generic;
 
internal sealed class HashSetEqualityComparer<T> : IEqualityComparer<HashSet<T>>
{
    public bool Equals(HashSet<T> x, HashSet<T> y)
    {
        if (x == y)
        {
            return true;
        }
        if (x == null || y == null)
        {
            return false;
        }
        EqualityComparer<T> @default = EqualityComparer<T>.Default;
        if (HashSet<T>.EqualityComparersAreEqual(x, y))
        {
            if (x.Count == y.Count)
            {
                return y.IsSubsetOfHashSetWithSameComparer(x);
            }
            return false;
        }
        foreach (T item in y)
        {
            bool flag = false;
            foreach (T item2 in x)
            {
                if (@default.Equals(item, item2))
                {
                    flag = true;
                    break;
                }
            }
            if (!flag)
            {
                return false;
            }
        }
        return true;
    }
 
    public int GetHashCode(HashSet<T> obj)
    {
        int num = 0;
        if (obj != null)
        {
            foreach (T item in obj)
            {
                if (item != null)
                {
                    num ^= item.GetHashCode();
                }
            }
        }
        return num;
    }
 
    public override bool Equals([NotNullWhen(true)] object obj)
    {
        return obj is HashSetEqualityComparer<T>;
    }
 
    public override int GetHashCode()
    {
        return EqualityComparer<T>.Default.GetHashCode();
    }
}