diff --git a/common/rdr/ZlibInStream.h b/common/rdr/ZlibInStream.h
new file mode 100644
index 0000000..c26b6d6
--- /dev/null
+++ b/common/rdr/ZlibInStream.h
@@ -0,0 +1,59 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software 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 software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+//
+// ZlibInStream streams from a compressed data stream ("underlying"),
+// decompressing with zlib on the fly.
+//
+
+#ifndef __RDR_ZLIBINSTREAM_H__
+#define __RDR_ZLIBINSTREAM_H__
+
+#include <rdr/InStream.h>
+
+struct z_stream_s;
+
+namespace rdr {
+
+  class ZlibInStream : public InStream {
+
+  public:
+
+    ZlibInStream(int bufSize=0);
+    virtual ~ZlibInStream();
+
+    void setUnderlying(InStream* is, int bytesIn);
+    void reset();
+    int pos();
+
+  private:
+
+    int overrun(int itemSize, int nItems, bool wait);
+    bool decompress(bool wait);
+
+    InStream* underlying;
+    int bufSize;
+    int offset;
+    z_stream_s* zs;
+    int bytesIn;
+    U8* start;
+  };
+
+} // end of namespace rdr
+
+#endif