Constant.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2011-2017 OpenFOAM Foundation
    Copyright (C) 2015-2024 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::Function1Types::Constant
 
Description
    Templated function that returns a constant value.
 
    Usage - for entry <entryName> returning the value <value>,
    can be specified is different formats.
 
    Inline specification:
    \verbatim
        <entryName>  constant <value>
    \endverbatim
 
    Dictionary format:
    \verbatim
        <entryName>
        {
            type    constant;
            value   <value>;
        }
    \endverbatim
 
SourceFiles
    Constant.C
    ConstantI.H
 
\*---------------------------------------------------------------------------*/
 
#ifndef Foam_Function1Types_Constant_H
#define Foam_Function1Types_Constant_H
 
#include "Function1.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace Function1Types
{
 
/*---------------------------------------------------------------------------*\
                           Class Constant Declaration
\*---------------------------------------------------------------------------*/
 
template<class Type>
class Constant
:
    public Function1<Type>
{
    // Private Data
 
        //- Constant value
        Type value_;
 
 
public:
 
    // Runtime type information
    TypeName("constant");
 
 
    // Generated Methods
 
        //- No copy assignment
        void operator=(const Constant<Type>&) = delete;
 
 
    // Constructors
 
        //- Construct from components
        Constant
        (
            const word& entryName,
            const Type& value,
            const objectRegistry* obrPtr = nullptr
        );
 
        //- Construct from entry name, dictionary and optional registry
        Constant
        (
            const word& entryName,
            const dictionary& dict,
            const objectRegistry* obrPtr = nullptr
        );
 
        //- Construct from entry name and Istream
        //  Reads the constant value without the Function1 type
        //  for backward compatibility
        Constant(const word& entryName, Istream& is);
 
        //- Copy constructor
        explicit Constant(const Constant<Type>& rhs);
 
        //- Return a clone
        virtual tmp<Function1<Type>> clone() const
        {
            return Function1<Type>::Clone(*this);
        }
 
 
    //- Destructor
    virtual ~Constant() = default;
 
 
    // Member Functions
 
        //- Change the constant value
        inline void reset(const Type& val);
 
        //- Value is independent of x
        virtual inline bool constant() const { return true; }
 
        //- Return constant value
        virtual inline Type value(const scalar) const;
 
        //- Integrate between two values
        virtual inline Type integrate(const scalar x1, const scalar x2) const;
 
        //- Return value as a function of (scalar) independent variable
        virtual tmp<Field<Type>> value(const scalarField& x) const;
 
        //- Write as primitive (inline) format
        virtual void writeData(Ostream& os) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Function1Types
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#include "ConstantI.H"
 
#ifdef NoRepository
    #include "Constant.C"
    #include "Function1New.C"
#endif
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //