zeroField.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2011-2017 OpenFOAM Foundation
    Copyright (C) 2019 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM 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 General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::zeroField
 
Description
    A class representing the concept of a field of 0 used to avoid unnecessary
    manipulations for objects which are known to be zero at compile-time.
 
    Used for example as the argument to a function in which certain terms are
    optional, see source terms in the MULES solvers.
 
\*---------------------------------------------------------------------------*/
 
#ifndef zeroField_H
#define zeroField_H
 
#include "zero.H"
#include "scalar.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                           Class zeroField Declaration
\*---------------------------------------------------------------------------*/
 
class zeroField
:
    public zero
{
public:
 
    // Constructors
 
        //- Default construct
        zeroField() noexcept = default;
 
 
    // Member Functions
 
        zeroField field() const noexcept
        {
            return zeroField{};
        }
 
 
    // Member Operators
 
        scalar operator[](const label) const noexcept
        {
            return scalar(0);
        }
 
        zeroField operator()() const noexcept
        {
            return zeroField{};
        }
 
        zeroField operator-() const noexcept
        {
            return zeroField{};
        }
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
// Global Operators
 
#include "zeroFieldI.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //