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/*! \internal \file
 * \brief
 * Implements a RAII encapsulation objects for PbcAiuc and t_pbc that
 * can be passed to listed forces.
 * Note: this is a header implementation to make inlining easier if needed.
 *
 * \author Victor Holanda <victor.holanda@cscs.ch>
 * \author Joe Jordan <ejjordan@kth.se>
 * \author Prashanth Kanduri <kanduri@cscs.ch>
 * \author Sebastian Keller <keller@cscs.ch>
 * \author Artem Zhmurov <zhmurov@gmail.com>
 */
#ifndef NBLIB_PBC_HPP
#define NBLIB_PBC_HPP

#include "nblib/box.h"
#include "gromacs/math/vec.h"
#include "gromacs/pbcutil/ishift.h"
#include "gromacs/pbcutil/pbc.h"
#include "gromacs/pbcutil/pbc_aiuc.h"

namespace nblib
{

/*! \brief life-time manager for pbcAiuc
 *
 */
class PbcHolderAiuc
{
public:
    //! \brief ctor
    explicit PbcHolderAiuc(PbcType pbcType, const Box& box)
    {
        setPbcAiuc(numPbcDimensions(pbcType), box.legacyMatrix(), &m_pbc);
    }

    //! \brief calculate pbc-aware r1-r2
    inline void dxAiuc(const rvec& r1, const rvec& r2, rvec dr) const
    {
        ::pbcDxAiuc(m_pbc, r1, r2, dr);
    }

private:
   PbcAiuc m_pbc;
};

/*! \brief life-time manager for t_pbc
 *
 */
class PbcHolder
{
public:
    //! \brief ctor
    explicit PbcHolder(PbcType pbcType, const Box& box)
    {
        set_pbc(&m_pbc, pbcType, box.legacyMatrix());
    }

    //! \brief calculate pbc-aware r1-r2, including the shift index
    template<class T>
    inline int dxAiuc(const gmx::BasicVector<T>& r1, const gmx::BasicVector<T>& r2,
                      gmx::BasicVector<T>& dr) const
    {
        return pbc_dx_aiuc(&m_pbc, r1.as_vec(), r2.as_vec(), dr.as_vec());
    }

private:
    t_pbc m_pbc;
};

/*! \brief dummy class used to turn off Pbc in listed forces
 *
 */
class NoPbc
{
public:

    //! \brief calculate r1-r2, ignore pbc
    template<class T>
    inline int dxAiuc(const gmx::BasicVector<T>& r1, const gmx::BasicVector<T>& r2, gmx::BasicVector<T>& dr) const
    {
        dr = r1 - r2;
        return gmx::c_centralShiftIndex;
    }
};

} // namespace nblib
#endif // NBLIB_PBC_HPP
