/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2017-2018 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/>.

Class
    Foam::decomposedBlockData

Description
    decomposedBlockData is a List<char> with IO on the master processor only.

SourceFiles
    decomposedBlockData.C

\*---------------------------------------------------------------------------*/

#ifndef decomposedBlockData_H
#define decomposedBlockData_H

#include "IOList.H"
#include "regIOobject.H"
#include "UPstream.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
                     Class decomposedBlockData Declaration
\*---------------------------------------------------------------------------*/

class decomposedBlockData
:
    public regIOobject,
    public List<char>
{
protected:

    // Protected data

        //- Type to use for gather
        const UPstream::commsTypes commsType_;

        //- Communicator for all parallel comms
        const label comm_;


    // Protected member functions

        //- Helper: determine number of processors whose recvSizes fits
        //  ito maxBufferSize
        static label calcNumProcs
        (
            const label comm,
            const off_t maxBufferSize,
            const labelUList& recvSizes,
            const label startProci
        );

        //- Read data into *this. ISstream is only valid on master.
        static bool readBlocks
        (
            const label comm,
            autoPtr<ISstream>& isPtr,
            List<char>& data,
            const UPstream::commsTypes commsType
        );


public:

    TypeName("decomposedBlockData");


    // Constructors

        //- Construct given an IOobject
        decomposedBlockData
        (
            const label comm,
            const IOobject&,
            const UPstream::commsTypes = UPstream::commsTypes::scheduled
        );

        //- Construct given an IOobject and for READ_IF_MODIFIED a List<char>
        decomposedBlockData
        (
            const label comm,
            const IOobject&,
            const UList<char>&,
            const UPstream::commsTypes = UPstream::commsTypes::scheduled
        );

        //- Construct by transferring the IOList contents
        decomposedBlockData
        (
            const label comm,
            const IOobject&,
            const Xfer<List<char>>&,
            const UPstream::commsTypes = UPstream::commsTypes::scheduled
        );


    //- Destructor
    virtual ~decomposedBlockData();


    // Member functions

        //- Read object
        virtual bool read();

        //- Write separated content. Assumes content is the serialised data
        //  and that the master data contains a header
        virtual bool writeData(Ostream&) const;

        //- Write using given format, version and compression
        virtual bool writeObject
        (
            IOstream::streamFormat,
            IOstream::versionNumber,
            IOstream::compressionType,
            const bool valid
        ) const;


    // Helpers

        //- Read header. Call only on master.
        static bool readMasterHeader(IOobject&, Istream&);

        //- Helper: write FoamFile IOobject header
        static void writeHeader
        (
            Ostream& os,
            const IOstream::versionNumber version,
            const IOstream::streamFormat format,
            const word& type,
            const string& note,
            const fileName& location,
            const word& name
        );

        //- Read selected block (non-seeking) + header information
        static autoPtr<ISstream> readBlock
        (
            const label blocki,
            Istream& is,
            IOobject& headerIO
        );

        //- Read master header information (into headerIO) and return
        //  data in stream. Note: isPtr is only valid on master.
        static autoPtr<ISstream> readBlocks
        (
            const label comm,
            const fileName& fName,
            autoPtr<ISstream>& isPtr,
            IOobject& headerIO,
            const UPstream::commsTypes commsType
        );

        //- Helper: gather single label. Note: using native Pstream.
        //  datas sized with num procs but undefined contents on
        //  slaves
        static void gather
        (
            const label comm,
            const label data,
            labelList& datas
        );

        //- Helper: gather data from (subset of) slaves. Returns
        //  recvData : received data
        //  recvOffsets : offset in data. recvOffsets is nProcs+1
        static void gatherSlaveData
        (
            const label comm,
            const UList<char>& data,
            const labelUList& recvSizes,

            const label startProc,
            const label nProcs,

            List<int>& recvOffsets,
            List<char>& recvData
        );

        //- Write *this. Ostream only valid on master. Returns starts of
        //  processor blocks
        static bool writeBlocks
        (
            const label comm,
            autoPtr<OSstream>& osPtr,
            List<std::streamoff>& start,
            const UList<char>& masterData,

            const labelUList& recvSizes,

            // optional slave data (on master)
            const PtrList<SubList<char>>& slaveData,

            const UPstream::commsTypes,
            const bool syncReturnState = true
        );

        //- Detect number of blocks in a file
        static label numBlocks(const fileName&);
};


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

} // End namespace Foam

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

#endif

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