<?php
/**
* @see https://github.com/laminas/laminas-validator for the canonical source repository
* @copyright https://github.com/laminas/laminas-validator/blob/master/COPYRIGHT.md
* @license https://github.com/laminas/laminas-validator/blob/master/LICENSE.md New BSD License
*/
namespace Laminas\Validator\Barcode;
class Issn extends AbstractAdapter
{
/**
* Constructor for this barcode adapter
*/
public function __construct()
{
$this->setLength([8, 13]);
$this->setCharacters('0123456789X');
$this->setChecksum('gtin');
}
/**
* Allows X on length of 8 chars
*
* @param string $value The barcode to check for allowed characters
* @return bool
*/
public function hasValidCharacters($value)
{
if (strlen($value) != 8) {
if (strpos($value, 'X') !== false) {
return false;
}
}
return parent::hasValidCharacters($value);
}
/**
* Validates the checksum
*
* @param string $value The barcode to check the checksum for
* @return bool
*/
public function hasValidChecksum($value)
{
if (strlen($value) == 8) {
$this->setChecksum('issn');
} else {
$this->setChecksum('gtin');
}
return parent::hasValidChecksum($value);
}
/**
* Validates the checksum ()
* ISSN implementation (reversed mod11)
*
* @param string $value The barcode to validate
* @return bool
*/
protected function issn($value)
{
$checksum = substr($value, -1, 1);
$values = str_split(substr($value, 0, -1));
$check = 0;
$multi = 8;
foreach ($values as $token) {
if ($token == 'X') {
$token = 10;
}
$check += ($token * $multi);
--$multi;
}
$check %= 11;
$check = ($check === 0 ? 0 : (11 - $check));
if ($check == $checksum) {
return true;
} elseif (($check == 10) && ($checksum == 'X')) {
return true;
}
return false;
}
}