/**
* Defined by Postman_Zend_Validate_Interface
*
* Returns true if and only if $value follows the Luhn algorithm (mod-10 checksum)
*
* @param string $value
* @return boolean
*/
public function isValid($value)
{
$this->_setValue($value);
if (null === self::$_filter) {
/**
* @see Postman_Zend_Filter_Digits
*/
require_once 'Zend/Filter/Digits.php';
self::$_filter = new Postman_Zend_Filter_Digits();
}
$valueFiltered = self::$_filter->filter($value);
$length = strlen($valueFiltered);
if ($length < 13 || $length > 19) {
$this->_error(self::LENGTH);
return false;
}
$sum = 0;
$weight = 2;
for ($i = $length - 2; $i >= 0; $i--) {
$digit = $weight * $valueFiltered[$i];
$sum += floor($digit / 10) + $digit % 10;
$weight = $weight % 2 + 1;
}
if ((10 - $sum % 10) % 10 != $valueFiltered[$length - 1]) {
$this->_error(self::CHECKSUM, $valueFiltered);
return false;
}
return true;
}
/**
* Defined by Postman_Zend_Validate_Interface
*
* Returns true if and only if $value only contains digit characters
*
* @param string $value
* @return boolean
*/
public function isValid($value)
{
if (!is_string($value) && !is_int($value) && !is_float($value)) {
$this->_error(self::INVALID);
return false;
}
$this->_setValue((string) $value);
if ('' === $this->_value) {
$this->_error(self::STRING_EMPTY);
return false;
}
if (null === self::$_filter) {
require_once 'Zend/Filter/Digits.php';
self::$_filter = new Postman_Zend_Filter_Digits();
}
if ($this->_value !== self::$_filter->filter($this->_value)) {
$this->_error(self::NOT_DIGITS);
return false;
}
return true;
}
