/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2013-2016 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 "globalIndex.H"

// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

template<class Type>
void Foam::globalIndex::gather
(
    const labelUList& off,
    const label comm,
    const labelList& procIDs,
    const UList<Type>& fld,
    List<Type>& allFld,
    const int tag,
    const Pstream::commsTypes commsType
)
{
    if (Pstream::myProcNo(comm) == procIDs[0])
    {
        allFld.setSize(off.last());

        // Assign my local data
        SubList<Type>(allFld, fld.size(), 0) = fld;

        if (commsType == Pstream::scheduled || commsType == Pstream::blocking)
        {
            for (label i = 1; i < procIDs.size(); i++)
            {
                SubList<Type> procSlot(allFld, off[i+1]-off[i], off[i]);

                if (contiguous<Type>())
                {
                    IPstream::read
                    (
                        commsType,
                        procIDs[i],
                        reinterpret_cast<char*>(procSlot.begin()),
                        procSlot.byteSize(),
                        tag,
                        comm
                    );
                }
                else
                {
                    IPstream fromSlave
                    (
                        commsType,
                        procIDs[i],
                        0,
                        tag,
                        comm
                    );
                    fromSlave >> procSlot;
                }
            }
        }
        else
        {
            // nonBlocking

            if (!contiguous<Type>())
            {
                FatalErrorInFunction
                    << "nonBlocking not supported for non-contiguous data"
                    << exit(FatalError);
            }

            label startOfRequests = Pstream::nRequests();

            // Set up reads
            for (label i = 1; i < procIDs.size(); i++)
            {
                SubList<Type> procSlot(allFld, off[i+1]-off[i], off[i]);

                IPstream::read
                (
                    commsType,
                    procIDs[i],
                    reinterpret_cast<char*>(procSlot.begin()),
                    procSlot.byteSize(),
                    tag,
                    comm
                );
            }

            // Wait for all to finish
            Pstream::waitRequests(startOfRequests);
        }
    }
    else
    {
        if (commsType == Pstream::scheduled || commsType == Pstream::blocking)
        {
            if (contiguous<Type>())
            {
                OPstream::write
                (
                    commsType,
                    procIDs[0],
                    reinterpret_cast<const char*>(fld.begin()),
                    fld.byteSize(),
                    tag,
                    comm
                );
            }
            else
            {
                OPstream toMaster
                (
                    commsType,
                    procIDs[0],
                    0,
                    tag,
                    comm
                );
                toMaster << fld;
            }
        }
        else
        {
            // nonBlocking

            if (!contiguous<Type>())
            {
                FatalErrorInFunction
                    << "nonBlocking not supported for non-contiguous data"
                    << exit(FatalError);
            }

            label startOfRequests = Pstream::nRequests();

            // Set up write
            OPstream::write
            (
                commsType,
                procIDs[0],
                reinterpret_cast<const char*>(fld.begin()),
                fld.byteSize(),
                tag,
                comm
            );

            // Wait for all to finish
            Pstream::waitRequests(startOfRequests);
        }
    }
}


template<class Type>
void Foam::globalIndex::gather
(
    const labelUList& off,
    const label comm,
    const labelList& procIDs,
    List<Type>& fld,
    const int tag,
    const Pstream::commsTypes commsType
)
{
    List<Type> allFld;

    gather(off, comm, procIDs, fld, allFld, tag, commsType);

    if (Pstream::myProcNo(comm) == procIDs[0])
    {
        fld.transfer(allFld);
    }
}


template<class Type>
void Foam::globalIndex::scatter
(
    const labelUList& off,
    const label comm,
    const labelList& procIDs,
    const UList<Type>& allFld,
    UList<Type>& fld,
    const int tag,
    const Pstream::commsTypes commsType
)
{
    if (Pstream::myProcNo(comm) == procIDs[0])
    {
        fld.deepCopy(SubList<Type>(allFld, off[1]-off[0]));

        if (commsType == Pstream::scheduled || commsType == Pstream::blocking)
        {
            for (label i = 1; i < procIDs.size(); i++)
            {
                const SubList<Type> procSlot
                (
                    allFld,
                    off[i+1]-off[i],
                    off[i]
                );

                if (contiguous<Type>())
                {
                    OPstream::write
                    (
                        commsType,
                        procIDs[i],
                        reinterpret_cast<const char*>(procSlot.begin()),
                        procSlot.byteSize(),
                        tag,
                        comm
                    );
                }
                else
                {
                    OPstream toSlave
                    (
                        commsType,
                        procIDs[i],
                        0,
                        tag,
                        comm
                    );
                    toSlave << procSlot;
                }
            }
        }
        else
        {
            // nonBlocking

            if (!contiguous<Type>())
            {
                FatalErrorInFunction
                    << "nonBlocking not supported for non-contiguous data"
                    << exit(FatalError);
            }

            label startOfRequests = Pstream::nRequests();

            // Set up writes
            for (label i = 1; i < procIDs.size(); i++)
            {
                const SubList<Type> procSlot
                (
                    allFld,
                    off[i+1]-off[i],
                    off[i]
                );

                OPstream::write
                (
                    commsType,
                    procIDs[i],
                    reinterpret_cast<const char*>(procSlot.begin()),
                    procSlot.byteSize(),
                    tag,
                    comm
                );
            }

            // Wait for all to finish
            Pstream::waitRequests(startOfRequests);
        }
    }
    else
    {
        if (commsType == Pstream::scheduled || commsType == Pstream::blocking)
        {
            if (contiguous<Type>())
            {
                IPstream::read
                (
                    commsType,
                    procIDs[0],
                    reinterpret_cast<char*>(fld.begin()),
                    fld.byteSize(),
                    tag,
                    comm
                );
            }
            else
            {
                IPstream fromMaster
                (
                    commsType,
                    procIDs[0],
                    0,
                    tag,
                    comm
                );
                fromMaster >> fld;
            }
        }
        else
        {
            // nonBlocking

            if (!contiguous<Type>())
            {
                FatalErrorInFunction
                    << "nonBlocking not supported for non-contiguous data"
                    << exit(FatalError);
            }

            label startOfRequests = Pstream::nRequests();

            // Set up read
            IPstream::read
            (
                commsType,
                procIDs[0],
                reinterpret_cast<char*>(fld.begin()),
                fld.byteSize(),
                tag,
                comm
            );

            // Wait for all to finish
            Pstream::waitRequests(startOfRequests);
        }
    }
}


// ************************************************************************* //
