BackCompatibleStringComparer.cs

namespace System.Collections.Specialized
{
    internal class BackCompatibleStringComparer : IEqualityComparer
    {
        internal static IEqualityComparer Default = new BackCompatibleStringComparer();

        internal BackCompatibleStringComparer()
        {
        }

        public unsafe static int GetHashCode(string obj)
        {
            fixed (char* ptr = obj)
            {
                int num = 5381;
                char* ptr2 = ptr;
                int num2;
                while ((num2 = *ptr2) != 0)
                {
                    num = (((num << 5) + num) ^ num2);
                    ptr2++;
                }
                return num;
            }
        }

        bool IEqualityComparer.Equals(object a, object b)
        {
            return object.Equals(a, b);
        }

        public virtual int GetHashCode(object o)
        {
            string text = o as string;
            if (text == null)
            {
                return o.GetHashCode();
            }
            return GetHashCode(text);
        }
    }
}