CommunicationBuffer.h

/*
 * CommunicationBuffer.h
 *
 *  Created on: 16 Oct 2017
 *      Author: tchipevn
 */
#ifdef ENABLE_MPI
#ifndef SRC_PARALLEL_COMMUNICATIONBUFFER_H_
#define SRC_PARALLEL_COMMUNICATIONBUFFER_H_
 
#include "molecules/MoleculeForwardDeclaration.h" 
#include "utils/mardyn_assert.h" 
 
#include <vector>
#include <stddef.h>
#include <mpi.h>
 
// do not uncomment the if, it will break halo copies of the kddecomposition!
//#if (not defined(NDEBUG))
#define LS1_SEND_UNIQUE_ID_FOR_HALO_COPIES
//#pragma message "Compilation info: Unique IDs of Halo-Molecules are always present."
//#endif
 
class CommunicationBuffer {
 
    friend class CommunicationBufferTest;
 
public:
    CommunicationBuffer() {
        clear();
    }
    size_t getDynamicSize();
 
    void clear();
 
    void resizeForAppendingLeavingMolecules(unsigned long numMols);
    void resizeForAppendingHaloMolecules(unsigned long numMols);
        void resizeForAppendingForceMolecules(unsigned long numMols);
 
    unsigned char * getDataForSending();
    size_t getNumElementsForSending();
    void resizeForRawBytes(unsigned long numBytes);
 
    // write
    void addLeavingMolecule(size_t indexOfMolecule, const Molecule& m);
    void addHaloMolecule(size_t indexOfMolecule, const Molecule& m);
        void addForceMolecule(size_t indexOfMolecule, const Molecule& m);
 
    // read
    void readLeavingMolecule(size_t indexOfMolecule, Molecule& m) const;
    void readHaloMolecule(size_t indexOfMolecule, Molecule& m) const;
    void readForceMolecule(size_t indexOfMolecule, Molecule& m) const;
 
    void resizeForReceivingMolecules(unsigned long& numLeaving, unsigned long& numHalo); 
    void resizeForReceivingMolecules(unsigned long& numForces);
 
    size_t getNumHalo() const {
        return _numHalo;
    }
 
    size_t getNumLeaving() const {
        return _numLeaving;
    }
        
        size_t getNumForces() const {
            return _numForces;
        }
 
    static MPI_Datatype getMPIDataType() {
        return MPI_CHAR;
    }
 
private:
    static size_t _numBytesHalo;
    static size_t _numBytesLeaving;
        static size_t _numBytesForces; // where is this set?
 
    enum class ParticleType_t {HALO=0, LEAVING=1, FORCE=3};
    size_t getStartPosition(ParticleType_t type, size_t indexOfMolecule) const;
 
    template<typename T>
    size_t emplaceValue(size_t indexInBytes, T passByValue);
 
    template<typename T>
    size_t readValue(size_t indexInBytes, T& passByReference) const;
 
    typedef unsigned char byte_t;
    std::vector<byte_t> _buffer;
    size_t _numLeaving, _numHalo, _numForces;
};
 
template<typename T>
inline size_t CommunicationBuffer::emplaceValue(size_t indexInBytes, T passByValue) {
    const size_t numBytesOfT = sizeof(T);
    size_t ret = indexInBytes + numBytesOfT;
 
    mardyn_assert(_buffer.size() >= ret);
 
    const byte_t * pointer = reinterpret_cast<byte_t *> (&passByValue);
    for (size_t i = 0; i < numBytesOfT; ++i) {
        _buffer[indexInBytes + i] = pointer[i];
    }
 
    return ret;
}
 
template<typename T>
inline size_t CommunicationBuffer::readValue(size_t indexInBytes, T& passByReference) const {
    const size_t numBytesOfT = sizeof(T);
    size_t ret = indexInBytes + numBytesOfT;
 
    mardyn_assert(_buffer.size() >= ret);
 
    byte_t * pointer = reinterpret_cast<byte_t *> (&passByReference);
    for (size_t i = 0; i < numBytesOfT; ++i) {
        pointer[i] = _buffer[indexInBytes + i];
    }
 
    return ret;
}
 
 
#endif /* SRC_PARALLEL_COMMUNICATIONBUFFER_H_ */
#endif /* ENABLE_MPI */