FNV-1a 64 bit string hash.cs

public static class ArhiFastHasher
{
    private static char[] Buffer = new char[1024];
 
    public static ulong HashStr(string str)
    {
        str.CopyTo(0, Buffer, 0, str.Length);
        
        ulong hash = 14695981039346656037UL; //offset
        for (var i = 0; i < str.Length; i++)
        {
            hash = hash ^ Buffer[i];
            hash *= 1099511628211UL; //prime
        }
        
        return hash;
    }
}