First checkin for OpenMesh 2.0

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@2 fdac6126-5c0c-442c-9429-916003d36597

Core/Utils/GenProg.hh

@@ -0,0 +1,147 @@
+//=============================================================================
+//                                                                            
+//                               OpenMesh                                     
+//        Copyright (C) 2003 by Computer Graphics Group, RWTH Aachen          
+//                           www.openmesh.org                                 
+//                                                                            
+//-----------------------------------------------------------------------------
+//                                                                            
+//                                License                                     
+//                                                                            
+//   This library is free software; you can redistribute it and/or modify it 
+//   under the terms of the GNU Lesser General Public License as published   
+//   by the Free Software Foundation, version 2.1.                           
+//                                                                             
+//   This library 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         
+//   Lesser General Public License for more details.                           
+//                                                                            
+//   You should have received a copy of the GNU Lesser General Public          
+//   License along with this library; if not, write to the Free Software       
+//   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                 
+//                                                                            
+//-----------------------------------------------------------------------------
+//                                                                            
+//   $Revision: 1801 $
+//   $Date: 2008-05-19 11:53:56 +0200 (Mo, 19. Mai 2008) $
+//                                                                            
+//=============================================================================
+
+
+//=============================================================================
+//
+//  Utils for generic/generative programming
+//
+//=============================================================================
+
+#ifndef OPENMESH_GENPROG_HH
+#define OPENMESH_GENPROG_HH
+
+
+//== INCLUDES =================================================================
+
+#include <OpenMesh/Core/System/config.h>
+
+
+//== NAMESPACES ===============================================================
+
+namespace OpenMesh {
+
+namespace GenProg  {
+#ifndef DOXY_IGNORE_THIS
+
+//== IMPLEMENTATION ===========================================================
+
+
+/// This type maps \c true or \c false to different types.
+template <bool b> struct Bool2Type { enum { my_bool = b }; };
+
+/// This class generates different types from different \c int 's.
+template <int i>  struct Int2Type  { enum { my_int = i }; };
+
+/// Handy typedef for Bool2Type<true> classes
+typedef Bool2Type<true> True;
+
+/// Handy typedef for Bool2Type<false> classes
+typedef Bool2Type<false> False;
+
+//-----------------------------------------------------------------------------
+/// compile time assertions 
+template <bool Expr> struct AssertCompile;
+template <> struct AssertCompile<true> {};
+
+
+
+//--- Template "if" w/ partial specialization ---------------------------------
+#if OM_PARTIAL_SPECIALIZATION
+
+
+template <bool condition, class Then, class Else>
+struct IF { typedef Then Result; };
+
+/** Template \c IF w/ partial specialization
+\code
+typedef IF<bool, Then, Else>::Result  ResultType;
+\endcode    
+*/
+template <class Then, class Else>
+struct IF<false, Then, Else> { typedef Else Result; };
+
+
+
+
+
+//--- Template "if" w/o partial specialization --------------------------------
+#else
+
+
+struct SelectThen 
+{
+  template <class Then, class Else> struct Select {
+    typedef Then Result;
+  };
+};
+
+struct SelectElse
+{
+  template <class Then, class Else> struct Select {
+    typedef Else Result;
+  };
+};
+
+template <bool condition> struct ChooseSelector {
+  typedef SelectThen Result;
+};
+
+template <> struct ChooseSelector<false> {
+  typedef SelectElse Result;
+};
+
+
+/** Template \c IF w/o partial specialization. Use it like
+\code
+typedef IF<bool, Then, Else>::Result  ResultType;
+\endcode    
+*/
+
+template <bool condition, class Then, class Else>
+class IF 
+{ 
+  typedef typename ChooseSelector<condition>::Result  Selector;
+public:
+  typedef typename Selector::template Select<Then, Else>::Result  Result;
+};
+
+#endif
+
+//=============================================================================
+#endif
+} // namespace GenProg
+} // namespace OpenMesh
+
+#define assert_compile(EXPR)                GenProg::AssertCompile<(EXPR)>();
+
+//=============================================================================
+#endif // OPENMESH_GENPROG_HH defined
+//=============================================================================