Imported existing code

libraries/include/boost/fusion/support/iterator_base.hpp

@@ -0,0 +1,31 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+#if !defined(FUSION_ITERATOR_BASE_05042005_1008)
+#define FUSION_ITERATOR_BASE_05042005_1008
+
+namespace boost { namespace fusion
+{
+    struct iterator_root {};
+
+    template <typename Iterator>
+    struct iterator_base : iterator_root
+    {
+        Iterator const&
+        cast() const
+        {
+            return static_cast<Iterator const&>(*this);
+        }
+
+        Iterator&
+        cast()
+        {
+            return static_cast<Iterator&>(*this);
+        }
+    };
+}}
+
+#endif