Rename DataEntry -> Function1

Function1 is an abstract base-class of run-time selectable unary
functions which may be composed of other Function1's allowing the user
to specify complex functions of a single scalar variable, e.g. time.
The implementations need not be a simple or continuous functions;
interpolated tables and polynomials are also supported.  In fact form of
mapping between a single scalar input and a single primitive type output
is supportable.

The primary application of Function1 is in time-varying boundary
conditions, it also used for other functions of time, e.g. injected mass
is spray simulations but is not limited to functions of time.

src/OpenFOAM/primitives/functions/Function1/Constant/Constant.C

@@ -0,0 +1,97 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "Constant.H"
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+template<class Type>
+Foam::Function1Types::Constant<Type>::Constant
+(
+    const word& entryName,
+    const dictionary& dict
+)
+:
+    Function1<Type>(entryName),
+    value_(pTraits<Type>::zero)
+{
+    Istream& is(dict.lookup(entryName));
+    word entryType(is);
+    is  >> value_;
+}
+
+
+template<class Type>
+Foam::Function1Types::Constant<Type>::Constant
+(
+    const word& entryName,
+    Istream& is
+)
+:
+    Function1<Type>(entryName),
+    value_(pTraits<Type>(is))
+{}
+
+
+template<class Type>
+Foam::Function1Types::Constant<Type>::Constant(const Constant<Type>& cnst)
+:
+    Function1<Type>(cnst),
+    value_(cnst.value_)
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+template<class Type>
+Foam::Function1Types::Constant<Type>::~Constant()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+template<class Type>
+Type Foam::Function1Types::Constant<Type>::value(const scalar x) const
+{
+    return value_;
+}
+
+
+template<class Type>
+Type Foam::Function1Types::Constant<Type>::integrate
+(
+    const scalar x1,
+    const scalar x2
+) const
+{
+    return (x2 - x1)*value_;
+}
+
+
+// * * * * * * * * * * * * * *  IOStream operators * * * * * * * * * * * * * //
+
+#include "ConstantIO.C"
+
+// ************************************************************************* //