interface/modules/zend_modules/library/Zend/Crypt/Symmetric/Padding/Pkcs7.php

   1 <?php
   2 /**
   3  * Zend Framework (http://framework.zend.com/)
   4  *
   5  * @link      http://github.com/zendframework/zf2 for the canonical source repository
   6  * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
   7  * @license   http://framework.zend.com/license/new-bsd New BSD License
   8  */
   9
  10 namespace Zend\Crypt\Symmetric\Padding;
  11
  12 /**
  13  * PKCS#7 padding
  14  */
  15 class Pkcs7 implements PaddingInterface
  16 {
  17
  18     /**
  19      * Pad the string to the specified size
  20      *
  21      * @param string $string    The string to pad
  22      * @param int    $blockSize The size to pad to
  23      *
  24      * @return string The padded string
  25      */
  26     public function pad($string, $blockSize = 32)
  27     {
  28         $pad = $blockSize - (strlen($string) % $blockSize);
  29         return $string . str_repeat(chr($pad), $pad);
  30     }
  31
  32     /**
  33      * Strip the padding from the supplied string
  34      *
  35      * @param string $string The string to trim
  36      *
  37      * @return string The unpadded string
  38      */
  39     public function strip($string)
  40     {
  41         $end  = substr($string, -1);
  42         $last = ord($end);
  43         $len  = strlen($string) - $last;
  44         if (substr($string, $len) == str_repeat($end, $last)) {
  45             return substr($string, 0, $len);
  46         }
  47         return false;
  48     }
  49 }