edge.H

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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::edge
 
Description
    An edge is a list of two point labels. The functionality it provides
    supports the discretisation on a 2-D flat mesh.
 
SourceFiles
    edgeI.H
 
\*---------------------------------------------------------------------------*/
 
#ifndef edge_H
#define edge_H
 
#include "FixedList.H"
#include "pointField.H"
#include "linePointRef.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
// Forward declaration of friend functions and operators
 
class edge;
inline bool operator==(const edge& a, const edge& b);
inline bool operator!=(const edge& a, const edge& b);
 
 
/*---------------------------------------------------------------------------*\
                            Class edge Declaration
\*---------------------------------------------------------------------------*/
 
class edge
:
    public FixedList<label, 2>
{
 
public:
 
    // Static Data Members
 
        static const char* const typeName;
 
 
    // Constructors
 
        //- Null constructor for lists
        inline edge();
 
        //- Construct from components
        inline edge(const label a, const label b);
 
        //- Construct from FixedList
        inline edge(const FixedList<label, 2>&);
 
        //- Construct from Istream
        inline edge(Istream&);
 
 
    // Member Functions
 
        //- Return start vertex label
        inline label start() const;
 
        //- Return start vertex label
        inline label& start();
 
        //- Return end vertex label
        inline label end() const;
 
        //- Return end vertex label
        inline label& end();
 
        //- Return true if connected to given edge
        inline bool connected(const edge& a) const;
 
        //- Return common vertex
        inline label commonVertex(const edge& a) const;
 
        //- Given one vertex, return the other
        inline label otherVertex(const label a) const;
 
        //- Flip the edge in-place.
        inline void flip();
 
        //- Return reverse edge
        inline edge reverseEdge() const;
 
        //- Return centre (centroid)
        inline point centre(const pointField&) const;
 
        //- Return the vector (end - start)
        inline vector vec(const pointField&) const;
 
        //- Return scalar magnitude
        inline scalar mag(const pointField&) const;
 
        //- Return edge line
        inline linePointRef line(const pointField&) const;
 
        //- Compare edges
        //  Returns:
        //  -  0: different
        //  - +1: identical
        //  - -1: same edge, but different orientation
        static inline int compare(const edge&, const edge&);
 
 
    // Friend Operators
 
        friend bool operator==(const edge& a, const edge& b);
        friend bool operator!=(const edge& a, const edge& b);
};
 
 
//- Hash specialisation for hashing edges - a commutative hash value.
//  Hash incrementally.
template<>
inline unsigned Hash<edge>::operator()(const edge& e, unsigned seed) const
{
    unsigned val = seed;
 
    if (e[0] < e[1])
    {
        val = Hash<label>()(e[0], val);
        val = Hash<label>()(e[1], val);
    }
    else
    {
        val = Hash<label>()(e[1], val);
        val = Hash<label>()(e[0], val);
    }
 
    return val;
}
 
 
//- Hash specialisation for hashing edges - a commutative hash value.
//  Hash incrementally.
template<>
inline unsigned Hash<edge>::operator()(const edge& e) const
{
    return Hash<edge>()(e, 0);
}
 
 
template<>
inline bool contiguous<edge>()  {return true;}
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#include "edgeI.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //