OpenMesh
OpenMesh/Core/Utils/GenProg.hh
00001 /*===========================================================================*\
00002  *                                                                           *
00003  *                               OpenMesh                                    *
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00006  *                                                                           *
00007  *---------------------------------------------------------------------------* 
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00016  *  If other files instantiate templates or use macros                       *
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00033 \*===========================================================================*/ 
00034 
00035 /*===========================================================================*\
00036  *                                                                           *             
00037  *   $Revision: 362 $                                                         *
00038  *   $Date: 2011-01-26 10:21:12 +0100 (Mi, 26 Jan 2011) $                   *
00039  *                                                                           *
00040 \*===========================================================================*/
00041 
00042 
00043 //=============================================================================
00044 //
00045 //  Utils for generic/generative programming
00046 //
00047 //=============================================================================
00048 
00049 #ifndef OPENMESH_GENPROG_HH
00050 #define OPENMESH_GENPROG_HH
00051 
00052 
00053 //== INCLUDES =================================================================
00054 
00055 #include <OpenMesh/Core/System/config.h>
00056 
00057 
00058 //== NAMESPACES ===============================================================
00059 
00060 namespace OpenMesh {
00061 
00062 namespace GenProg  {
00063 #ifndef DOXY_IGNORE_THIS
00064 
00065 //== IMPLEMENTATION ===========================================================
00066 
00067 
00069 template <bool b> struct Bool2Type { enum { my_bool = b }; };
00070 
00072 template <int i>  struct Int2Type  { enum { my_int = i }; };
00073 
00075 typedef Bool2Type<true> True;
00076 
00078 typedef Bool2Type<false> False;
00079 
00080 //-----------------------------------------------------------------------------
00082 template <bool Expr> struct AssertCompile;
00083 template <> struct AssertCompile<true> {};
00084 
00085 
00086 
00087 //--- Template "if" w/ partial specialization ---------------------------------
00088 #if OM_PARTIAL_SPECIALIZATION
00089 
00090 
00091 template <bool condition, class Then, class Else>
00092 struct IF { typedef Then Result; };
00093 
00099 template <class Then, class Else>
00100 struct IF<false, Then, Else> { typedef Else Result; };
00101 
00102 
00103 
00104 
00105 
00106 //--- Template "if" w/o partial specialization --------------------------------
00107 #else
00108 
00109 
00110 struct SelectThen 
00111 {
00112   template <class Then, class Else> struct Select {
00113     typedef Then Result;
00114   };
00115 };
00116 
00117 struct SelectElse
00118 {
00119   template <class Then, class Else> struct Select {
00120     typedef Else Result;
00121   };
00122 };
00123 
00124 template <bool condition> struct ChooseSelector {
00125   typedef SelectThen Result;
00126 };
00127 
00128 template <> struct ChooseSelector<false> {
00129   typedef SelectElse Result;
00130 };
00131 
00132 
00139 template <bool condition, class Then, class Else>
00140 class IF 
00141 { 
00142   typedef typename ChooseSelector<condition>::Result  Selector;
00143 public:
00144   typedef typename Selector::template Select<Then, Else>::Result  Result;
00145 };
00146 
00147 #endif
00148 
00149 //=============================================================================
00150 #endif
00151 } // namespace GenProg
00152 } // namespace OpenMesh
00153 
00154 #define assert_compile(EXPR)                GenProg::AssertCompile<(EXPR)>();
00155 
00156 //=============================================================================
00157 #endif // OPENMESH_GENPROG_HH defined
00158 //=============================================================================