public function cspn(string $mask, int $start = 0, int $length = null): int
    {
        if ($length === null) {
            $value = \strcspn($this->value, $mask, $start);
        } else {
            $value = \strcspn(
                $this->value,
                $mask,
                $start,
                $length
            );
        }

        return (int) $value;
    }