Luhn.php
1.72 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
<?php
namespace Faker\Calculator;
use InvalidArgumentException;
/**
* Utility class for generating and validating Luhn numbers.
*
* Luhn algorithm is used to validate credit card numbers, IMEI numbers, and
* National Provider Identifier numbers.
*
* @see http://en.wikipedia.org/wiki/Luhn_algorithm
*/
class Luhn
{
/**
* @param string $number
* @return int
*/
private static function checksum($number)
{
$number = (string) $number;
$length = strlen($number);
$sum = 0;
for ($i = $length - 1; $i >= 0; $i -= 2) {
$sum += $number{$i};
}
for ($i = $length - 2; $i >= 0; $i -= 2) {
$sum += array_sum(str_split($number{$i} * 2));
}
return $sum % 10;
}
/**
* @param $partialNumber
* @return string
*/
public static function computeCheckDigit($partialNumber)
{
$checkDigit = self::checksum($partialNumber . '0');
if ($checkDigit === 0) {
return 0;
}
return (string) (10 - $checkDigit);
}
/**
* Checks whether a number (partial number + check digit) is Luhn compliant
*
* @param string $number
* @return bool
*/
public static function isValid($number)
{
return self::checksum($number) === 0;
}
/**
* Generate a Luhn compliant number.
*
* @param string $partialValue
*
* @return string
*/
public static function generateLuhnNumber($partialValue)
{
if (!preg_match('/^\d+$/', $partialValue)) {
throw new InvalidArgumentException('Argument should be an integer.');
}
return $partialValue . Luhn::computeCheckDigit($partialValue);
}
}