public function linesAreDifferent($aIndex, $bIndex)
    {
        $lineA = $this->a[$aIndex];
        $lineB = $this->b[$bIndex];

        if ($this->options['ignoreWhitespace']) {
            $replace = ["\t", ' '];
            $lineA = str_replace($replace, '', $lineA);
            $lineB = str_replace($replace, '', $lineB);
        }

        if ($this->options['ignoreCase']) {
            $lineA = strtolower($lineA);
            $lineB = strtolower($lineB);
        }

        if ($lineA != $lineB) {
            return true;
        }

        return false;
    }