public function mapHeaders(array $current)
    {
        if (count($this->headerRow) > 0) {
            if (count($this->headerRow) !== count($current)) {
                throw new RuntimeException(
                    "The number of entries in: " . implode(',', $current) .
                    " does not match the header: " . implode(',', $this->headerRow)
                );
            }
            return array_combine(
                $this->headerRow,
                $current
            );
        }
        return $current;
    }