/**
* Constructor
*
* @param Context $context Use context
* @param int $start Characters to be cut from the start (could be negative - numbered from end)
* @param int $length String piece length
*
* @throws \InvalidArgumentException
*/
public function __construct(Context $context, $start, $length)
{
parent::__construct($context);
if ($length < 0) {
throw new \InvalidArgumentException('Cut length cannot be a negative number');
}
$this->start = (int) $start;
$this->length = (int) $length;
}
/**
* Constructor
*
* @param Context $context Use context
* @param array $allowed Allowed tag names
*/
public function __construct(Context $context, array $allowed = array())
{
parent::__construct($context);
$this->allowedTags = $this->mergeTags($allowed);
}