Add ISBN-10 & ISBN-13 codes

readme.md

@@ -225,6 +225,8 @@ Each of the generator properties (like `name`, `address`, and `lorem`) are calle
 
     ean13          // '4006381333931'
     ean8           // '73513537'
+    isbn13         // '9790404436093'
+    isbn10         // '4881416324
 
 ### `Faker\Provider\Miscellaneous`
 

src/Faker/Generator.php

@@ -21,6 +21,8 @@
  *
  * @property string $ean13
  * @property string $ean8
+ * @property string $isbn13
+ * @property string $isbn10
  *
  * @property string $phoneNumber
  *

src/Faker/Provider/Barcode.php

@@ -4,6 +4,7 @@
 
 /**
  * @see http://en.wikipedia.org/wiki/EAN-13
+ * @see http://en.wikipedia.org/wiki/ISBN
  */
 class Barcode extends \Faker\Provider\Base
 {
@@ -27,6 +28,38 @@ protected static function eanChecksum($input)
         return (10 - $sums % 10) % 10;
     }
 
+    /**
+     * ISBN-10 check digit
+     * @link http://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digits
+     *
+     * @param  string           $input ISBN without check-digit
+     * @throws \LengthException When wrong input length passed
+     *
+     * @return integer Check digit
+     */
+    protected static function isbnChecksum($input)
+    {
+        // We're calculating check digit for ISBN-10
+        // so, the length of the input should be 9
+        $length = 9;
+
+        if (strlen($input) != $length) {
+            throw new \LengthException(sprintf('Input length should be equal to %d', $length));
+        }
+
+        $digits = str_split($input);
+        array_walk(
+            $digits,
+            function (&$digit, $position) {
+                $digit = (10 - $position) * $digit;
+            }
+        );
+        $result = (11 - array_sum($digits) % 11) % 11;
+
+        // 10 is replaced by X
+        return ($result < 10)?$result:'X';
+    }
+
     /**
      * Get a random EAN13 barcode.
      * @return string
@@ -46,4 +79,32 @@ public function ean8()
     {
         return $this->ean(8);
     }
+
+    /**
+     * Get a random ISBN-10 code
+     * @link http://en.wikipedia.org/wiki/International_Standard_Book_Number
+     *
+     * @return string
+     * @example '4881416324'
+     */
+    public function isbn10()
+    {
+        $code = $this->numerify(str_repeat('#', 9));
+
+        return $code . static::isbnChecksum($code);
+    }
+
+    /**
+     * Get a random ISBN-13 code
+     * @link http://en.wikipedia.org/wiki/International_Standard_Book_Number
+     *
+     * @return string
+     * @example '9790404436093'
+     */
+    public function isbn13()
+    {
+        $code = '97' . static::numberBetween(8, 9) . $this->numerify(str_repeat('#', 9));
+
+        return $code . static::eanChecksum($code);
+    }
 }