StaticAssert.H

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/*---------------------------------------------------------------------------*\
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License
    This file is part of OpenFOAM.

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Class
    Foam::StaticAssertionFailed

Description
    Macros and classes to provide static (compile-time) assertions.

    Ideas from various sources
    (http://www.ddj.com/cpp/184401547, http://www.boost.org)

\*---------------------------------------------------------------------------*/

#ifndef StaticAssert_H
#define StaticAssert_H

namespace Foam
{

//- Forward declaration of StaticAssertionFailed.
//  Leave as an incomplete class so that sizeof(..) fails
template<bool Truth> class StaticAssertionFailed;

/*---------------------------------------------------------------------------*\
                    Class StaticAssertionFailed Declaration
\*---------------------------------------------------------------------------*/

//- Specialization for successful assertions
template<>
class StaticAssertionFailed<true>
{};


//- Helper class for handling static assertions
template<unsigned Test>
class StaticAssertionTest {};

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// internal use:
// ~~~~~~~~~~~~~
// paste together strings, even if an argument is itself a macro
#define StaticAssertMacro(X,Y)  StaticAssertMacro1(X,Y)
#define StaticAssertMacro1(X,Y) StaticAssertMacro2(X,Y)
#define StaticAssertMacro2(X,Y) X##Y

// external use:
// ~~~~~~~~~~~~~
#define StaticAssert(Test)                                                   \
    typedef ::Foam::StaticAssertionTest                                      \
    <                                                                        \
        sizeof( ::Foam::StaticAssertionFailed< ((Test) ? true : false) > )   \
    > StaticAssertMacro(StaticAssertionTest, __LINE__)

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //