File indexing completed on 2024-12-22 05:36:21

 <?php
 
 /**
  * Class that handles operations involving percent-encoding in URIs.
  *
  * @warning
  *      Be careful when reusing instances of PercentEncoder. The object
  *      you use for normalize() SHOULD NOT be used for encode(), or
  *      vice-versa.
  */
 class HTMLPurifier_PercentEncoder
 {
 
     /**
      * Reserved characters to preserve when using encode().
      * @type array
      */
     protected $preserve = array();
 
     /**
      * String of characters that should be preserved while using encode().
      * @param bool $preserve
      */
     public function __construct($preserve = false)
     {
         // unreserved letters, ought to const-ify
         for ($i = 48; $i <= 57; $i++) { // digits
             $this->preserve[$i] = true;
         }
         for ($i = 65; $i <= 90; $i++) { // upper-case
             $this->preserve[$i] = true;
         }
         for ($i = 97; $i <= 122; $i++) { // lower-case
             $this->preserve[$i] = true;
         }
         $this->preserve[45] = true; // Dash         -
         $this->preserve[46] = true; // Period       .
         $this->preserve[95] = true; // Underscore   _
         $this->preserve[126]= true; // Tilde        ~
 
         // extra letters not to escape
         if ($preserve !== false) {
             for ($i = 0, $c = strlen($preserve); $i < $c; $i++) {
                 $this->preserve[ord($preserve[$i])] = true;
             }
         }
     }
 
     /**
      * Our replacement for urlencode, it encodes all non-reserved characters,
      * as well as any extra characters that were instructed to be preserved.
      * @note
      *      Assumes that the string has already been normalized, making any
      *      and all percent escape sequences valid. Percents will not be
      *      re-escaped, regardless of their status in $preserve
      * @param string $string String to be encoded
      * @return string Encoded string.
      */
     public function encode($string)
     {
         $ret = '';
         for ($i = 0, $c = strlen($string); $i < $c; $i++) {
             if ($string[$i] !== '%' && !isset($this->preserve[$int = ord($string[$i])])) {
                 $ret .= '%' . sprintf('%02X', $int);
             } else {
                 $ret .= $string[$i];
             }
         }
         return $ret;
     }
 
     /**
      * Fix up percent-encoding by decoding unreserved characters and normalizing.
      * @warning This function is affected by $preserve, even though the
      *          usual desired behavior is for this not to preserve those
      *          characters. Be careful when reusing instances of PercentEncoder!
      * @param string $string String to normalize
      * @return string
      */
     public function normalize($string)
     {
         if ($string == '') {
             return '';
         }
         $parts = explode('%', $string);
         $ret = array_shift($parts);
         foreach ($parts as $part) {
             $length = strlen($part);
             if ($length < 2) {
                 $ret .= '%25' . $part;
                 continue;
             }
             $encoding = substr($part, 0, 2);
             $text     = substr($part, 2);
             if (!ctype_xdigit($encoding)) {
                 $ret .= '%25' . $part;
                 continue;
             }
             $int = hexdec($encoding);
             if (isset($this->preserve[$int])) {
                 $ret .= chr($int) . $text;
                 continue;
             }
             $encoding = strtoupper($encoding);
             $ret .= '%' . $encoding . $text;
         }
         return $ret;
     }
 }
 
 // vim: et sw=4 sts=4