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<?php
namespace Faker\Calculator;
/**
* Utility class for validating EAN-8 and EAN-13 numbers
*
* @package Faker\Calculator
*/
class Ean
{
/** @var string EAN validation pattern */
const PATTERN = '/^(?:\d{8}|\d{13})$/';
/**
* Computes the checksum of an EAN number.
*
* @see https://en.wikipedia.org/wiki/International_Article_Number
*
* @param string $digits
* @return int
*/
public static function checksum($digits)
{
$length = strlen($digits);
$even = 0;
for ($i = $length - 1; $i >= 0; $i -= 2) {
$even += $digits[$i];
}
$odd = 0;
for ($i = $length - 2; $i >= 0; $i -= 2) {
$odd += $digits[$i];
}
return (10 - ((3 * $even + $odd) % 10)) % 10;
}
/**
* Checks whether the provided number is an EAN compliant number and that
* the checksum is correct.
*
* @param string $ean An EAN number
* @return boolean
*/
public static function isValid($ean)
{
if (!preg_match(self::PATTERN, $ean)) {
return false;
}
return self::checksum(substr($ean, 0, -1)) === intval(substr($ean, -1));
}
}