Initial base_from_member commit

[SVN r11086]

include/boost/utility/base_from_member.hpp

@@ -0,0 +1,59 @@
+//  boost utility/base_from_member.hpp header file  --------------------------//
+
+//  (C) Copyright Daryle Walker 2001.  Permission to copy, use, modify, sell
+//  and distribute this software is granted provided this copyright
+//  notice appears in all copies.  This software is provided "as is" without
+//  express or implied warranty, and with no claim as to its suitability for
+//  any purpose.
+
+//  See http://www.boost.org for most recent version including documentation.
+
+#ifndef BOOST_UTILITY_BASE_FROM_MEMBER_HPP
+#define BOOST_UTILITY_BASE_FROM_MEMBER_HPP
+
+#include <boost/utility_fwd.hpp>  // self include
+
+
+namespace boost
+{
+
+//  Base-from-member class template  -----------------------------------------//
+
+// Helper to initialize a base object so a derived class can use this
+// object in the initialization of another base class.  Used by
+// Dietmar Kuehl from ideas by Ron Klatcho to solve the problem of a
+// base class needing to be initialized by a member.
+
+// Contributed by Daryle Walker
+
+template < typename MemberType, int UniqueID >
+class base_from_member
+{
+protected:
+    MemberType  member;
+
+    explicit  base_from_member()
+        : member()
+        {}
+
+    template< typename T1 >
+    explicit base_from_member( T1 x1 )
+        : member( x1 )
+        {}
+
+    template< typename T1, typename T2 >
+    explicit  base_from_member( T1 x1, T2 x2 )
+        : member( x1, x2 )
+        {}
+
+    template< typename T1, typename T2, typename T3 >
+    explicit  base_from_member( T1 x1, T2 x2, T3 x3 )
+        : member( x1, x2, x3 ) 
+        {}
+
+};  // boost::base_from_member
+
+}  // namespace boost
+
+
+#endif  // BOOST_UTILITY_BASE_FROM_MEMBER_HPP