xml.php

<?php

/**
 * Escape special characters.
 *
 * See http://en.wikipedia.org/wiki/XML#Escaping
 */
function ec_dreammail_escape_xml($string) {
  $search = array('<', '>', '&', '"', "'");
  $replace = array('&lt;', '&gt;', '&amp;', '&quot;', '&apos;');
  
  return str_replace($search, $replace, $string);
}

/**
 * Returns FALSE if there are unsafe characters.
 */
function ec_dreammail_sanitize_xml($string) {
  $length = strlen($string);
  for ($i = 0; $i < $length; $i++) {
    $current = ord($string[$i]);
    if (!(($current == 0x9) || ($current == 0xA) || ($current == 0xD) || 
        (($current >= 0x20) && ($current <= 0xD7FF)) || 
        (($current >= 0xE000) && ($current <= 0xFFFD)) || 
        (($current >= 0x10000) && ($current <= 0x10FFFF)))) {
      return FALSE;
    }
  }
  return TRUE;
}