#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#ifdef USE_MPI

#include <mpi.h>

#include "cdi.h"
#include "namespace.h"
#include "pio_serialize.h"
#include "pio_util.h"

static struct
{
  int cdidt;
  MPI_Datatype mpidt;
} dtDict[]
  = {
#if MPI_VERSION == 1 || (MPI_VERSION == 2 && MPI_SUBVERSION < 2)
#define CDI_DT_MATCH_NEEDED 1
  { DATATYPE_INT8, MPI_SIGNED_CHAR },
  { DATATYPE_INT16, MPI_SHORT },
#else
  { DATATYPE_INT8, MPI_INT8_T },
  { DATATYPE_INT16, MPI_INT16_T },
#endif
  { DATATYPE_INT, MPI_INT },
  { DATATYPE_FLT64, MPI_DOUBLE },
  { DATATYPE_TXT, MPI_CHAR },
  { DATATYPE_UCHAR, MPI_UNSIGNED_CHAR }
};

static inline int
lookupDt(int datatype)
{
  for (size_t i = 0; i < sizeof (dtDict) / sizeof (dtDict[0]); ++i)
    if (dtDict[i].cdidt == datatype)
      return i;
  abort();
}

#if CDI_DT_MATCH_NEEDED
static int dtDictMatchComplete = 0;

static inline void
  dtDictFixMPIType(int i, int typeclass, int size)
{
  MPI_Aint lb, extent;
  xmpi(MPI_Type_get_extent(dtDict[i].mpidt, &lb, &extent));
  if ((int)extent != size)
    {
      /* type size mismatch needs to be fixed */
      MPI_Type_match_size(typeclass, size, &dtDict[i].mpidt);
    }
}

static void
  setupDtDict()
{
  dtDictFixMPIType(lookupDt(DATATYPE_INT8), MPI_TYPECLASS_INTEGER,
                   (int)sizeof (int8_t));
  dtDictFixMPIType(lookupDt(DATATYPE_INT8), MPI_TYPECLASS_INTEGER,
                   (int)sizeof (int16_t));
}
#endif

int serializeGetSizeMPI(int count, int datatype, void *context)
{
  int size;
  xmpi(MPI_Pack_size(count, dtDict[lookupDt(datatype)].mpidt,
                     *(MPI_Comm *)context, &size));
  return size;
}


void serializePackMPI(void *data, int count, int datatype,
                      void *buf, int buf_size, int *position, void *context)
{
  xmpi(MPI_Pack(data, count, dtDict[lookupDt(datatype)].mpidt,
                buf, buf_size, position, *(MPI_Comm *)context));
}

void serializeUnpackMPI(void *buf, int buf_size, int *position,
                        void *data, int count, int datatype, void *context)
{
  xmpi(MPI_Unpack(buf, buf_size, position, data, count,
                  dtDict[lookupDt(datatype)].mpidt, *(MPI_Comm *)context));
}

void serializeSetMPI()
{
#if CDI_DT_MATCH_NEEDED
  if (!dtDictMatchComplete)
    setupDtDict();
#endif
  namespaceSwitchSet(NSSWITCH_SERIALIZE_GET_SIZE, serializeGetSizeMPI);
  namespaceSwitchSet(NSSWITCH_SERIALIZE_PACK, serializePackMPI);
  namespaceSwitchSet(NSSWITCH_SERIALIZE_UNPACK, serializeUnpackMPI);
}


#endif
/*
 * Local Variables:
 * c-file-style: "Java"
 * c-basic-offset: 2
 * indent-tabs-mode: nil
 * show-trailing-whitespace: t
 * require-trailing-newline: t
 * End:
 */
