Files
openfoam/src/OpenFOAM/primitives/hashes/Hash/Hash.H

134 lines
3.4 KiB
C++

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 1991-2009 OpenCFD Ltd.
\\/ 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 2 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, write to the Free Software Foundation,
Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Class
Foam::Hash
Description
Hash function class for primitives. All non-primitives used to hash
entries on hash tables likely need a specialized version of this class.
\*---------------------------------------------------------------------------*/
#ifndef Hash_H
#define Hash_H
#include "label.H"
#include "uLabel.H"
#include "Hasher.H"
#include "pTraits.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
/*---------------------------------------------------------------------------*\
Class Hash Declaration
\*---------------------------------------------------------------------------*/
template<class PrimitiveType>
class Hash
{
public:
Hash()
{}
unsigned operator()(const PrimitiveType& p, unsigned seed) const
{
return Hasher(&p, sizeof(p), seed);
}
unsigned operator()(const PrimitiveType& p) const
{
return Hasher(&p, sizeof(p));
}
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
//- Hash specialization for hashing pointer addresses.
// Treat a pointer like a long.
// This should work for both 32-bit and 64-bit pointers.
template<>
class Hash<void*>
{
public:
Hash()
{}
unsigned operator()(const void* const& p, unsigned seed) const
{
return Hash<long>()(long(p), seed);
}
unsigned operator()(const void* const& p) const
{
return Hash<long>()(long(p));
}
};
//- Hash specialization for hashing labels
template<>
class Hash<Foam::label>
{
public:
Hash()
{}
//- Incrementally hash a label.
// This will necessarily return a different value than the
// non-incremental version.
unsigned operator()(const label p, unsigned seed) const
{
return Hasher(&p, sizeof(label), seed);
}
//- Return the unsigned representation of a label.
// This helps if people have relied on the hash value corresponding to
// the natural order.
unsigned operator()(const label p) const
{
return p;
}
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //