DER encoding: Added CertificateDataVisitor and use in Certificate::decode.
diff --git a/ndn-cpp/encoding/der/visitor/public-key-visitor.hpp b/ndn-cpp/encoding/der/visitor/public-key-visitor.hpp
new file mode 100644
index 0000000..54dfb66
--- /dev/null
+++ b/ndn-cpp/encoding/der/visitor/public-key-visitor.hpp
@@ -0,0 +1,27 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/**
+ * Copyright (C) 2013 Regents of the University of California.
+ * @author: Yingdi Yu <yingdi@cs.ucla.edu>
+ * @author: Jeff Thompson <jefft0@remap.ucla.edu>
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NDN_PUBLIC_KEY_VISITOR_HPP
+#define NDN_PUBLIC_KEY_VISITOR_HPP
+
+#include "no-arguments-visitor.hpp"
+
+namespace ndn {
+
+namespace der {
+
+class PublicKeyVisitor : public NoArgumentsVisitor {
+ public:
+ virtual ndnboost::any visit(DerSequence& );
+};
+
+} // der
+
+}
+
+#endif