--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/openid/xrds.inc	Tue Dec 23 14:28:28 2008 +0100
@@ -0,0 +1,82 @@
+<?php
+// $Id: xrds.inc,v 1.2 2007/10/15 09:40:42 goba Exp $
+
+// Global variables to track parsing state
+$xrds_open_elements = array();
+$xrds_services = array();
+$xrds_current_service = array();
+
+/**
+ * Main entry point for parsing XRDS documents
+ */
+function xrds_parse($xml) {
+  global $xrds_services;
+
+  $parser = xml_parser_create_ns();
+  xml_set_element_handler($parser, '_xrds_element_start', '_xrds_element_end');
+  xml_set_character_data_handler($parser, '_xrds_cdata');
+
+  xml_parse($parser, $xml);
+  xml_parser_free($parser);
+
+  return $xrds_services;
+}
+
+/**
+ * Parser callback functions
+ */
+function _xrds_element_start(&$parser, $name, $attribs) {
+  global $xrds_open_elements;
+
+  $xrds_open_elements[] = _xrds_strip_namespace($name);
+}
+
+function _xrds_element_end(&$parser, $name) {
+  global $xrds_open_elements, $xrds_services, $xrds_current_service;
+
+  $name = _xrds_strip_namespace($name);
+  if ($name == 'SERVICE') {
+    if (in_array(OPENID_NS_2_0 .'/signon', $xrds_current_service['types']) ||
+        in_array(OPENID_NS_2_0 .'/server', $xrds_current_service['types'])) {
+      $xrds_current_service['version'] = 2;
+    }
+    elseif (in_array(OPENID_NS_1_1, $xrds_current_service['types']) ||
+            in_array(OPENID_NS_1_0, $xrds_current_service['types'])) {
+      $xrds_current_service['version'] = 1;
+    }
+    if (!empty($xrds_current_service['version'])) {
+      $xrds_services[] = $xrds_current_service;
+    }
+    $xrds_current_service = array();
+  }
+  array_pop($xrds_open_elements);
+}
+
+function _xrds_cdata(&$parser, $data) {
+  global $xrds_open_elements, $xrds_services, $xrds_current_service;
+  $path = strtoupper(implode('/', $xrds_open_elements));
+  switch ($path) {
+    case 'XRDS/XRD/SERVICE/TYPE':
+      $xrds_current_service['types'][] = $data;
+      break;
+    case 'XRDS/XRD/SERVICE/URI':
+      $xrds_current_service['uri'] = $data;
+      break;
+    case 'XRDS/XRD/SERVICE/DELEGATE':
+      $xrds_current_service['delegate'] = $data;
+      break;
+    case 'XRDS/XRD/SERVICE/LOCALID':
+      $xrds_current_service['localid'] = $data;
+      break;
+  }
+}
+
+function _xrds_strip_namespace($name) {
+  // Strip namespacing.
+  $pos = strrpos($name, ':');
+  if ($pos !== FALSE) {
+    $name = substr($name, $pos + 1, strlen($name));
+  }
+
+  return $name;
+}
\ No newline at end of file