refined previous commit

Encoder/XmlEncoder.php

@@ -54,15 +54,24 @@ public function encode($data, $format)
      */
     public function decode($data, $format)
     {
-        $this->assertNoCustomDocType($data);
         $internalErrors = libxml_use_internal_errors(true);
         $disableEntities = libxml_disable_entity_loader(true);
         libxml_clear_errors();
 
-        $xml = simplexml_load_string($data);
+        $dom = new \DOMDocument();
+        $dom->loadXML($data);
+
         libxml_use_internal_errors($internalErrors);
         libxml_disable_entity_loader($disableEntities);
 
+        foreach ($dom->childNodes as $child) {
+            if ($child->nodeType === XML_DOCUMENT_TYPE_NODE) {
+                throw new UnexpectedValueException('Document types are not allowed.');
+            }
+        }
+
+        $xml = simplexml_import_dom($dom);
+
         if ($error = libxml_get_last_error()) {
             throw new UnexpectedValueException($error->message);
         }
@@ -291,17 +300,6 @@ private function buildXml($parentNode, $data)
         throw new UnexpectedValueException('An unexpected value could not be serialized: '.var_export($data, true));
     }
 
-    private function assertNoCustomDocType($data)
-    {
-        $dom = new \DOMDocument;
-        $dom->loadXML($data);
-        foreach ($dom->childNodes as $child) {
-            if ($child->nodeType === XML_DOCUMENT_TYPE_NODE) {
-                throw new \InvalidArgumentException('Document types are not allowed.');
-            }
-        }
-    }
-
     /**
      * Selects the type of node to create and appends it to the parent.
      *