public function similarity($text1, $text2)
    {
        $similarity = 0;
        $hash1 = $this->hashString($text1);
        $hash2 = $this->hashString($text2);        
        
        $keys = array_keys(array_intersect_key($hash1, $hash2));
        foreach($keys as $key)
        {
            if($hash1[$key] === $hash2[$key] && $hash1[$key] >= $this->limit)
            {
                $similarity += $hash1[$key];
            }
        }        
        return $similarity;
    }