Create "Luhn" rule

docs/CreditCard.md

@@ -44,3 +44,4 @@ See also:
 - [Bank](Bank.md)
 - [BankAccount](BankAccount.md)
 - [Bic](Bic.md)
+- [Luhn](Luhn.md)

docs/Luhn.md

@@ -0,0 +1,23 @@
+# Luhn
+
+- `Luhn()`
+
+Validate whether a given input is a [Luhn][] number.
+
+```php
+v::luhn()->validate('2222400041240011'); // true
+v::luhn()->validate('respect!'); // false
+```
+
+## Changelog
+
+Version | Description
+--------|-------------
+  2.0.0 | Created
+
+[Luhn]: https://en.wikipedia.org/wiki/Luhn_algorithm
+***
+See also:
+
+- [CreditCard](CreditCard.md)
+- [Imei](Imei.md)

docs/VALIDATORS.md

@@ -187,6 +187,7 @@
 - [Imei](Imei.md)
 - [Ip](Ip.md)
 - [Json](Json.md)
+- [Luhn](Luhn.md)
 - [MacAddress](MacAddress.md)
 - [NfeAccessKey](NfeAccessKey.md)
 - [Nif](Nif.md)
@@ -286,6 +287,7 @@
 - [LeapYear](LeapYear.md)
 - [Length](Length.md)
 - [Lowercase](Lowercase.md)
+- [Luhn](Luhn.md)
 - [MacAddress](MacAddress.md)
 - [Max](Max.md)
 - [Mimetype](Mimetype.md)

library/Exceptions/LuhnException.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Exceptions;
+
+class LuhnException extends ValidationException
+{
+    public static $defaultTemplates = [
+        self::MODE_DEFAULT => [
+            self::STANDARD => '{{name}} must be a valid Luhn number',
+        ],
+        self::MODE_NEGATIVE => [
+            self::STANDARD => '{{name}} must not be a valid Luhn number',
+        ],
+    ];
+}

library/Rules/CreditCard.php

@@ -64,40 +64,13 @@ class CreditCard extends AbstractRule
             return false;
         }
 
-        if (!$this->verifyMod10($input)) {
+        if (!(new Luhn())->validate($input)) {
             return false;
         }
 
         return $this->verifyBrand($input);
     }
 
-    /**
-     * Returns whether the input matches the Luhn algorithm or not.
-     *
-     * @param string $input
-     *
-     * @return bool
-     */
-    private function verifyMod10($input)
-    {
-        $sum = 0;
-        $input = strrev($input);
-        for ($i = 0; $i < mb_strlen($input); ++$i) {
-            $current = mb_substr($input, $i, 1);
-            if ($i % 2 == 1) {
-                $current *= 2;
-                if ($current > 9) {
-                    $firstDigit = $current % 10;
-                    $secondDigit = ($current - $firstDigit) / 10;
-                    $current = $firstDigit + $secondDigit;
-                }
-            }
-            $sum += $current;
-        }
-
-        return $sum % 10 == 0;
-    }
-
     /**
      * Returns whether the input matches the defined credit card brand or not.
      *

library/Rules/Imei.php

@@ -33,12 +33,6 @@ class Imei extends AbstractRule
             return false;
         }
 
-        $sum = 0;
-        for ($position = 0; $position < (self::IMEI_SIZE - 1); ++$position) {
-            $number = $numbers[$position] * (($position % 2) + 1);
-            $sum += ($number % 10) + intval($number / 10);
-        }
-
-        return (ceil($sum / 10) * 10) - $sum == $numbers[14];
+        return (new Luhn())->validate($numbers);
     }
 }

library/Rules/Luhn.php

@@ -0,0 +1,49 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Rules;
+
+/**
+ * @link https://en.wikipedia.org/wiki/Luhn_algorithm
+ */
+class Luhn extends AbstractRule
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function validate($input)
+    {
+        if (!(new Digit())->validate($input)) {
+            return false;
+        }
+
+        return $this->isValid($input);
+    }
+
+    private function isValid($input): bool
+    {
+        $sum = 0;
+        $numDigits = strlen($input);
+        $parity = $numDigits % 2;
+        for ($i = 0; $i < $numDigits; ++$i) {
+            $digit = substr($input, $i, 1);
+            if ($parity == ($i % 2)) {
+                $digit <<= 1;
+                if (9 < $digit) {
+                    $digit = $digit - 9;
+                }
+            }
+            $sum += $digit;
+        }
+
+        return 0 == ($sum % 10);
+    }
+}

library/Validator.php

@@ -95,6 +95,7 @@ use Respect\Validation\Rules\Key;
  * @method static Validator leapYear()
  * @method static Validator length(int $min = null, int $max = null, bool $inclusive = true)
  * @method static Validator lowercase()
+ * @method static Validator luhn()
  * @method static Validator macAddress()
  * @method static Validator max(mixed $maxValue, bool $inclusive = true)
  * @method static Validator mimetype(string $mimetype)

tests/unit/Rules/LuhnTest.php

@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Rules;
+
+/**
+ * @group  rule
+ * @covers \Respect\Validation\Rules\Luhn
+ */
+class LuhnTest extends RuleTestCase
+{
+    public function providerForValidInput()
+    {
+        $rule = new Luhn();
+
+        return [
+            [$rule, '2222400041240011'],
+            [$rule, '340316193809364'],
+            [$rule, '6011000990139424'],
+            [$rule, '2223000048400011'],
+        ];
+    }
+
+    public function providerForInvalidInput()
+    {
+        $rule = new Luhn();
+
+        return [
+            [$rule, '2222400041240021'],
+            [$rule, '340316193809334'],
+            [$rule, '6011000990139421'],
+            [$rule, '2223000048400010'],
+        ];
+    }
+}