diff --git a/model/sync-global-function.cc b/model/sync-global-function.cc
new file mode 100644
index 0000000..8c38083
--- /dev/null
+++ b/model/sync-global-function.cc
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ *         卞超轶 Chaoyi Bian <bcy@pku.edu.cn>
+ *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#define TIXML_USE_STL
+
+#include <string>
+#include <tinyxml.h>
+#include "sync-state.h"
+#include "sync-std-name-info.h"
+
+using namespace std;
+
+namespace Sync
+{
+  string & operator >> (string &DataBuffer, State &state)
+  {
+    TiXmlDocument doc;
+
+    doc.Parse(DataBuffer.c_str());
+    for (TiXmlElement *iterator = doc.RootElement(); iterator != NULL; iterator = iterator->NextSiblingElement())
+    {
+      if (strcmp(iterator->Attribute("action"), "UPDATE") == 0)
+      {
+	TiXmlElement *name = iterator->FirstChildElement();
+	TiXmlElement *session = name->NextSiblingElement();
+	TiXmlElement *sequence = session->NextSiblingElement();
+	NameInfoConstPtr info = StdNameInfo::FindOrCreate(name->GetText());
+	SeqNo seqNo(atoi(session->GetText()), atoi(sequence->GetText()));
+
+	state.update(info, seqNo);
+      }
+      else
+      {
+	TiXmlElement *name = iterator->FirstChildElement();
+	NameInfoConstPtr info = StdNameInfo::FindOrCreate(name->GetText());
+	state.remove(info);
+      }
+    }
+
+    return DataBuffer;
+  }
+}
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