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openmesh/src/OpenMesh/Core/Utils/GenProg.hh
2019-01-15 11:21:12 +01:00

161 lines
5.9 KiB
C++

/* ========================================================================= *
* *
* OpenMesh *
* Copyright (c) 2001-2015, RWTH-Aachen University *
* Department of Computer Graphics and Multimedia *
* All rights reserved. *
* www.openmesh.org *
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*---------------------------------------------------------------------------*
* This file is part of OpenMesh. *
*---------------------------------------------------------------------------*
* *
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* 1. Redistributions of source code must retain the above copyright notice, *
* this list of conditions and the following disclaimer. *
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* 2. Redistributions in binary form must reproduce the above copyright *
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* 3. Neither the name of the copyright holder nor the names of its *
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS *
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* ========================================================================= */
//=============================================================================
//
// 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> TrueType;
/// Handy typedef for Bool2Type<false> classes
typedef Bool2Type<false> FalseType;
//-----------------------------------------------------------------------------
/// 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
//=============================================================================