stream_ieg.c

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

#include <float.h>

#include "dmemory.h"

#include "error.h"
#include "file.h"
#include "cdi.h"
#include "cdi_int.h"
#include "varscan.h"
#include "datetime.h"
#include "ieg.h"
#include "stream_scan.h"
#include "stream_ieg.h"
#include "exse.h"


#ifdef HAVE_LIBIEG

typedef struct {
  int param;
  int level;
} iegcompvar_t;


static
int iegInqDatatype(int prec)
{
  return (prec == EXSE_DOUBLE_PRECISION) ? CDI_DATATYPE_FLT64 : CDI_DATATYPE_FLT32;
}

static
int iegDefDatatype(int datatype)
{
  if ( datatype == CDI_DATATYPE_CPX32 || datatype == CDI_DATATYPE_CPX64 )
    Error("CDI/IEG library does not support complex numbers!");

  if ( datatype != CDI_DATATYPE_FLT32 && datatype != CDI_DATATYPE_FLT64 )
    datatype = CDI_DATATYPE_FLT32;

  return (datatype == CDI_DATATYPE_FLT64) ? EXSE_DOUBLE_PRECISION : EXSE_SINGLE_PRECISION;
}

void iegReadRecord(stream_t *streamptr, double *data, size_t *nmiss)
{
  int vlistID = streamptr->vlistID;
  int fileID  = streamptr->fileID;
  int tsID    = streamptr->curTsID;
  int vrecID  = streamptr->tsteps[tsID].curRecID;
  int recID   = streamptr->tsteps[tsID].recIDs[vrecID];
  int varID   = streamptr->tsteps[tsID].records[recID].varID;
  off_t recpos = streamptr->tsteps[tsID].records[recID].position;

  fileSetPos(fileID, recpos, SEEK_SET);

  void *iegp = streamptr->record->exsep;
  int status = iegRead(fileID, iegp);
  if ( status != 0 ) Error("Could not read IEG record!");

  iegInqDataDP(iegp, data);

  double missval = vlistInqVarMissval(vlistID, varID);
  int gridID  = vlistInqVarGrid(vlistID, varID);
  size_t size = gridInqSize(gridID);

  streamptr->numvals += size;

  *nmiss = 0;
  for ( size_t i = 0; i < size; i++ )
    if ( DBL_IS_EQUAL(data[i], missval) || DBL_IS_EQUAL(data[i], (float)missval) )
      {
	data[i] = missval;
	(*nmiss)++;
      }
}

static
int iegGetZaxisType(int iegleveltype)
{
  int leveltype = 0;

  switch ( iegleveltype )
    {
    case IEG_LTYPE_SURFACE:
      {
	leveltype = ZAXIS_SURFACE;
	break;
      }
    case IEG_LTYPE_99:
    case IEG_LTYPE_ISOBARIC:
      {
	leveltype = ZAXIS_PRESSURE;
	break;
      }
    case IEG_LTYPE_HEIGHT:
      {
	leveltype = ZAXIS_HEIGHT;
	break;
      }
    case IEG_LTYPE_ALTITUDE:
      {
	leveltype = ZAXIS_ALTITUDE;
	break;
      }
    case IEG_LTYPE_HYBRID:
    case IEG_LTYPE_HYBRID_LAYER:
      {
	leveltype = ZAXIS_HYBRID;
	break;
      }
    case IEG_LTYPE_LANDDEPTH:
    case IEG_LTYPE_LANDDEPTH_LAYER:
      {
	leveltype = ZAXIS_DEPTH_BELOW_LAND;
	break;
      }
    case IEG_LTYPE_SEADEPTH:
      {
	leveltype = ZAXIS_DEPTH_BELOW_SEA;
	break;
      }
    default:
      {
	leveltype = ZAXIS_GENERIC;
	break;
      }
    }

  return leveltype;
}


static void iegDefTime(int *pdb, int64_t date, int time, int taxisID)
{
  int timetype = (taxisID != -1) ? taxisInqType(taxisID) : -1;
  if ( timetype == TAXIS_ABSOLUTE || timetype == TAXIS_RELATIVE )
    {
      int year, month, day, hour, minute, second;
      cdiDecodeDate(date, &year, &month, &day);
      cdiDecodeTime(time, &hour, &minute, &second);

      IEG_P_Year(pdb)     = year;
      IEG_P_Month(pdb)    = month;
      IEG_P_Day(pdb)      = day;
      IEG_P_Hour(pdb)     = hour;
      IEG_P_Minute(pdb)   = minute;

      pdb[15] = 1;
      pdb[16] = 0;
      pdb[17] = 0;
      pdb[18] = 10;
      pdb[36] = 1;
    }

  pdb[5] = 128;
}

/* find smallest power of 10 in [1000,10000000] that upon
 * multiplication results in fractional part close to zero for all
 * arguments */
static double
calc_resfac(double xfirst, double xlast, double xinc, double yfirst, double ylast, double yinc)
{
  double resfac = 1000.0;
  enum {
    nPwrOf10 = 5,
    nMultTests = 6,
  };
  static const double scaleFactors[nPwrOf10]
    = { 1000, 10000, 100000, 1000000, 10000000 };
  double vals[nMultTests] = { xfirst, xlast, xinc, yfirst, ylast, yinc };

  for (size_t j = 0; j < nPwrOf10; ++j )
    {
      double scaleBy = scaleFactors[j];
      bool fractionalScale = false;
      for (size_t i = 0; i < nMultTests; ++i )
        {
          fractionalScale = fractionalScale || fabs(vals[i]*scaleBy - round(vals[i]*scaleBy)) > FLT_EPSILON;
        }
      if ( !fractionalScale )
        {
          resfac = scaleBy;
          break;
        }
    }

  return resfac;
}

static
void iegDefGrid(int *gdb, int gridID)
{
  int projID = gridInqProj(gridID);
  if ( projID != CDI_UNDEFID && gridInqProjType(projID) == CDI_PROJ_RLL ) gridID = projID;

  int gridtype = gridInqType(gridID);
  int projtype = CDI_UNDEFID;
  if ( gridtype == GRID_PROJECTION && gridInqProjType(gridID) == CDI_PROJ_RLL ) projtype = CDI_PROJ_RLL;

  size_t xsize = gridInqXsize(gridID);
  size_t ysize = gridInqYsize(gridID);

  cdi_check_gridsize_int_limit("IEG", xsize*ysize);

  if ( gridtype == GRID_GENERIC )
    {
      if ( (ysize == 32  || ysize == 48 || ysize == 64 || ysize == 96  || ysize == 160) &&
	   (xsize == 2*ysize || xsize == 1) )
	{
	  gridtype = GRID_GAUSSIAN;
	  gridChangeType(gridID, gridtype);
	}
      else if ( (xsize == 1 && ysize == 1) || (xsize == 0 && ysize == 0) )
	{
	  gridtype = GRID_LONLAT;
	  gridChangeType(gridID, gridtype);
	}
      else if ( gridInqXvals(gridID, NULL) && gridInqYvals(gridID, NULL) )
	{
	  gridtype = GRID_LONLAT;
	  gridChangeType(gridID, gridtype);
	}
    }
  else if ( gridtype == GRID_CURVILINEAR )
    {
      gridtype = GRID_LONLAT;
    }

  bool lrotated = (projtype == CDI_PROJ_RLL);

  if ( gridtype == GRID_LONLAT || gridtype == GRID_GAUSSIAN || projtype == CDI_PROJ_RLL )
    {
      double xfirst = 0, xlast = 0, xinc = 0;
      double yfirst = 0, ylast = 0, yinc = 0;

      if ( xsize == 0 ) xsize = 1;
      else
	{
	  xfirst = gridInqXval(gridID,       0);
	  xlast  = gridInqXval(gridID, xsize-1);
	  xinc   = gridInqXinc(gridID);
	}

      if ( ysize == 0 ) ysize = 1;
      else
	{
	  yfirst = gridInqYval(gridID,       0);
	  ylast  = gridInqYval(gridID, ysize-1);
	  yinc   = gridInqYinc(gridID);
	}

      if ( gridtype == GRID_GAUSSIAN )
	IEG_G_GridType(gdb) = 4;
      else if ( lrotated )
	IEG_G_GridType(gdb) = 10;
      else
	IEG_G_GridType(gdb) = 0;

      double resfac = calc_resfac(xfirst, xlast, xinc, yfirst, ylast, yinc);
      int iresfac = (int)resfac;
      if ( iresfac == 1000 ) iresfac = 0;

      IEG_G_ResFac(gdb)   = iresfac;

      IEG_G_NumLon(gdb)   = (int)xsize;
      IEG_G_NumLat(gdb)   = (int)ysize;
      IEG_G_FirstLat(gdb) = (int)lround(yfirst*resfac);
      IEG_G_LastLat(gdb)  = (int)lround(ylast*resfac);
      IEG_G_FirstLon(gdb) = (int)lround(xfirst*resfac);
      IEG_G_LastLon(gdb)  = (int)lround(xlast*resfac);
      IEG_G_LonIncr(gdb)  = (int)lround(xinc*resfac);
      if ( fabs(xinc*resfac - IEG_G_LonIncr(gdb)) > FLT_EPSILON )
	IEG_G_LonIncr(gdb) = 0;

      if ( gridtype == GRID_GAUSSIAN )
	IEG_G_LatIncr(gdb) = (int)ysize/2;
      else
	{
	  IEG_G_LatIncr(gdb) = (int)lround(yinc*resfac);
	  if ( fabs(yinc*resfac - IEG_G_LatIncr(gdb)) > FLT_EPSILON )
	    IEG_G_LatIncr(gdb) = 0;

	  if ( IEG_G_LatIncr(gdb) < 0 ) IEG_G_LatIncr(gdb) = -IEG_G_LatIncr(gdb);
	}

      if ( IEG_G_NumLon(gdb) > 1 && IEG_G_NumLat(gdb) == 1 )
	if ( IEG_G_LonIncr(gdb) != 0 && IEG_G_LatIncr(gdb) == 0 ) IEG_G_LatIncr(gdb) = IEG_G_LonIncr(gdb);

      if ( IEG_G_NumLon(gdb) == 1 && IEG_G_NumLat(gdb) > 1 )
	if ( IEG_G_LonIncr(gdb) == 0 && IEG_G_LatIncr(gdb) != 0 ) IEG_G_LonIncr(gdb) = IEG_G_LatIncr(gdb);

      IEG_G_ResFlag(gdb) = (IEG_G_LatIncr(gdb) == 0 || IEG_G_LonIncr(gdb) == 0) ? 0 : 128;

      if ( lrotated )
	{
          double xpole = 0, ypole = 0, angle = 0;
          gridInqParamRLL(gridID, &xpole, &ypole, &angle);

	  IEG_G_LatSP(gdb) = - (int)lround(ypole * resfac);
	  IEG_G_LonSP(gdb) =   (int)lround((xpole + 180) * resfac);
	  IEG_G_Size(gdb)  = 42;
	}
      else
	{
	  IEG_G_Size(gdb)  = 32;
	}
    }
  else
    {
      Error("Unsupported grid type: %s", gridNamePtr(gridtype));
    }

  IEG_G_ScanFlag(gdb) = 64;
}

static
void pdbDefLevel(int *pdb, int leveltype, int level1, int level2)
{
  IEG_P_LevelType(pdb) = leveltype;
  IEG_P_Level1(pdb)    = level1;
  IEG_P_Level2(pdb)    = level2;
}

static
void iegDefLevel(int *pdb, int *gdb, double *vct, int zaxisID, int levelID)
{
  double level;
  int ilevel;

  int leveltype = zaxisInqType(zaxisID);
  if ( leveltype == ZAXIS_GENERIC )
    {
      Message("Changed zaxis type from %s to %s",
	      zaxisNamePtr(leveltype), zaxisNamePtr(ZAXIS_PRESSURE));
      leveltype = ZAXIS_PRESSURE;
      zaxisChangeType(zaxisID, leveltype);
      zaxisDefUnits(zaxisID, "Pa");
    }

  /*  IEG_G_NumVCP(gdb) = 0; */

  switch (leveltype)
    {
    case ZAXIS_SURFACE:
      {
        pdbDefLevel(pdb, IEG_LTYPE_SURFACE, 0, (int)(zaxisInqLevel(zaxisID, levelID)));
	break;
      }
    case ZAXIS_HYBRID:
      {
	if ( zaxisInqLbounds(zaxisID, NULL) && zaxisInqUbounds(zaxisID, NULL) )
          pdbDefLevel(pdb, IEG_LTYPE_HYBRID_LAYER, (int)(zaxisInqLbound(zaxisID, levelID)),
                      (int)(zaxisInqUbound(zaxisID, levelID)));
	else
          pdbDefLevel(pdb, IEG_LTYPE_HYBRID, 0, (int)(zaxisInqLevel(zaxisID, levelID)));

	int vctsize = zaxisInqVctSize(zaxisID);
	if ( vctsize > 100 )
	  {
            static bool vct_warning = true;
	    /*	    IEG_G_NumVCP(gdb) = 0; */
	    if ( vct_warning )
	      {
		Warning("VCT size of %d is too large (maximum is 100). Set to 0!", vctsize);
		vct_warning = false;
	      }
	  }
	else
	  {
	    IEG_G_Size(gdb) += (vctsize*4);
	    memcpy(vct, zaxisInqVctPtr(zaxisID), (size_t)vctsize/2*sizeof(double));
	    memcpy(vct+50, zaxisInqVctPtr(zaxisID)+vctsize/2, (size_t)vctsize/2*sizeof(double));
	  }
	break;
      }
    case ZAXIS_PRESSURE:
      {
	double dum;
	char units[CDI_MAX_NAME];

	level = zaxisInqLevel(zaxisID, levelID);
	if ( level < 0 ) Warning("pressure level of %f Pa is below 0.", level);

	zaxisInqUnits(zaxisID, units);
	if ( memcmp(units, "hPa", 3) == 0 || memcmp(units, "mb",2 ) == 0 )
	  level = level*100;

	ilevel = (int) level;
	if ( level < 32768 && (level < 100 || modf(level/100, &dum) > 0) )
          pdbDefLevel(pdb, IEG_LTYPE_99, 0, ilevel);
	else
          pdbDefLevel(pdb, IEG_LTYPE_ISOBARIC, 0, ilevel/100);

        break;
      }
    case ZAXIS_HEIGHT:
      {
	level = zaxisInqLevel(zaxisID, levelID);
        pdbDefLevel(pdb, IEG_LTYPE_HEIGHT, 0, (int)level);
	break;
      }
    case ZAXIS_ALTITUDE:
      {
	level = zaxisInqLevel(zaxisID, levelID);
        pdbDefLevel(pdb, IEG_LTYPE_ALTITUDE, 0, (int)level);
	break;
      }
    case ZAXIS_DEPTH_BELOW_LAND:
      {
	if ( zaxisInqLbounds(zaxisID, NULL) && zaxisInqUbounds(zaxisID, NULL) )
          pdbDefLevel(pdb, IEG_LTYPE_LANDDEPTH_LAYER, (int)(zaxisInqLbound(zaxisID, levelID)), (int)(zaxisInqUbound(zaxisID, levelID)));
	else
          pdbDefLevel(pdb, IEG_LTYPE_LANDDEPTH, 0, (int)(zaxisInqLevel(zaxisID, levelID)));

	break;
      }
    case ZAXIS_DEPTH_BELOW_SEA:
      {
	level = zaxisInqLevel(zaxisID, levelID);
        pdbDefLevel(pdb, IEG_LTYPE_SEADEPTH, 0, (int)level);
	break;
      }
    case ZAXIS_ISENTROPIC:
      {
	level = zaxisInqLevel(zaxisID, levelID);
        pdbDefLevel(pdb, 113, 0, (int)level);
	break;
      }
    default:
      {
	Error("Unsupported zaxis type: %s", zaxisNamePtr(leveltype));
	break;
      }
    }
}


void iegCopyRecord(stream_t *streamptr2, stream_t *streamptr1)
{
  streamFCopyRecord(streamptr2, streamptr1, "IEG");
}


void iegDefRecord(stream_t *streamptr)
{
  Record *record = streamptr->record;

  int vlistID = streamptr->vlistID;
  int byteorder = streamptr->byteorder;

  int varID   = record->varID;
  int levelID = record->levelID;
  int tsID    = streamptr->curTsID;

  int gridID  = vlistInqVarGrid(vlistID, varID);
  int zaxisID = vlistInqVarZaxis(vlistID, varID);

  iegrec_t *iegp = (iegrec_t*) record->exsep;
  iegInitMem(iegp);
  for ( int i = 0; i < 37; i++ ) iegp->ipdb[i] = -1;

  iegp->byteswap = getByteswap(byteorder);

  int param = vlistInqVarParam(vlistID, varID);
  int pdis, pcat, pnum;
  cdiDecodeParam(param, &pnum, &pcat, &pdis);
  IEG_P_Parameter(iegp->ipdb) = pnum;
  if ( pdis == 255 ) IEG_P_CodeTable(iegp->ipdb) = pcat;

  int64_t date = streamptr->tsteps[tsID].taxis.vdate;
  int time = streamptr->tsteps[tsID].taxis.vtime;
  iegDefTime(iegp->ipdb, date, time, vlistInqTaxis(vlistID));
  iegDefGrid(iegp->igdb, gridID);
  iegDefLevel(iegp->ipdb, iegp->igdb, iegp->vct, zaxisID, levelID);

  iegp->dprec = iegDefDatatype(record->prec);
}


void iegWriteRecord(stream_t *streamptr, const double *data)
{
  Record *record = streamptr->record;
  iegrec_t *iegp = (iegrec_t*) record->exsep;

  int fileID = streamptr->fileID;
  size_t gridsize = gridInqSize(record->gridID);

  double refval = data[0];
  for ( size_t i = 1; i < gridsize; i++ )
    if ( data[i] < refval ) refval = data[i];

  iegp->refval = refval;

  iegDefDataDP(iegp, data);
  iegWrite(fileID, iegp);
}

static
void iegAddRecord(stream_t *streamptr, int param, int *pdb, int *gdb, double *vct,
		  size_t recsize, off_t position, int prec)
{
  int vlistID = streamptr->vlistID;
  int tsID    = streamptr->curTsID;
  int recID   = recordNewEntry(streamptr, tsID);
  record_t *record = &streamptr->tsteps[tsID].records[recID];

  int level1, level2;
  if ( IEG_P_LevelType(pdb) == IEG_LTYPE_HYBRID_LAYER )
    {
      level1 = IEG_P_Level1(pdb);
      level2 = IEG_P_Level2(pdb);
    }
  else
    {
      level1 = IEG_P_Level2(pdb);
      level2 = 0;
      if ( IEG_P_LevelType(pdb) == 100 ) level1 *= 100;
    }

  record->size     = recsize;
  record->position = position;
  record->param    = param;
  record->ilevel   = level1;
  record->ilevel2  = level2;
  record->ltype    = IEG_P_LevelType(pdb);

  int gridtype = (IEG_G_GridType(gdb) == 0) ? GRID_LONLAT :
                 (IEG_G_GridType(gdb) == 10) ? GRID_PROJECTION :
                 (IEG_G_GridType(gdb) == 4) ? GRID_GAUSSIAN : GRID_GENERIC;

  grid_t *grid = (grid_t *)Malloc(sizeof (*grid));
  grid_init(grid);
  cdiGridTypeInit(grid, gridtype, IEG_G_NumLon(gdb)*IEG_G_NumLat(gdb));
  size_t xsize = (size_t)IEG_G_NumLon(gdb);
  size_t ysize = (size_t)IEG_G_NumLat(gdb);
  grid->x.size = xsize;
  grid->y.size = ysize;
  grid->x.inc  = 0;
  grid->y.inc  = 0;
  grid->x.flag = 0;

  int iresfac = IEG_G_ResFac(gdb);
  if ( iresfac == 0 ) iresfac = 1000;
  double resfac = 1./(double) iresfac;

  /* if ( IEG_G_FirstLon != 0 || IEG_G_LastLon != 0 ) */
  {
    if ( xsize > 1 )
      {
	if ( IEG_G_ResFlag(gdb) && IEG_G_LonIncr(gdb) > 0 )
	  grid->x.inc = IEG_G_LonIncr(gdb) * resfac;
	else
	  grid->x.inc = (IEG_G_LastLon(gdb) - IEG_G_FirstLon(gdb)) * resfac / (xsize - 1);

	/* correct xinc if necessary */
	if ( IEG_G_FirstLon(gdb) == 0 && IEG_G_LastLon(gdb) > 354000 )
	  {
	    double xinc = 360. / xsize;
            /* FIXME: why not use grid->x.inc != xinc as condition? */
	    if ( fabs(grid->x.inc-xinc) > 0.0 )
	      {
		grid->x.inc = xinc;
		if ( CDI_Debug ) Message("set xinc to %g", grid->x.inc);
	      }
	  }
      }
    grid->x.first = IEG_G_FirstLon(gdb) * resfac;
    grid->x.last  = IEG_G_LastLon(gdb)  * resfac;
    grid->x.flag  = 2;
  }
  grid->y.flag = 0;
  /* if ( IEG_G_FirstLat != 0 || IEG_G_LastLat != 0 ) */
  {
    if ( ysize > 1 )
      {
	if ( IEG_G_ResFlag(gdb) && IEG_G_LatIncr(gdb) > 0 )
	  grid->y.inc = IEG_G_LatIncr(gdb) * resfac;
	else
	  grid->y.inc = (IEG_G_LastLat(gdb) - IEG_G_FirstLat(gdb)) * resfac / (ysize - 1);
      }
    grid->y.first = IEG_G_FirstLat(gdb) * resfac;
    grid->y.last  = IEG_G_LastLat(gdb)  * resfac;
    grid->y.flag  = 2;
  }

  double xpole = 0, ypole = 0;
  if ( IEG_G_GridType(gdb) == 10 )
    {
      xpole =   IEG_G_LonSP(gdb) * resfac - 180;
      ypole = - IEG_G_LatSP(gdb) * resfac;
      grid->projtype = CDI_PROJ_RLL;
    }

  struct addIfNewRes gridAdded = cdiVlistAddGridIfNew(vlistID, grid, 0);
  int gridID = gridAdded.Id;
  if ( !gridAdded.isNew ) Free(grid);
  else if ( gridtype == GRID_PROJECTION ) gridDefParamRLL(gridID, xpole, ypole, 0);

  int leveltype = iegGetZaxisType(IEG_P_LevelType(pdb));
  if ( leveltype == ZAXIS_HYBRID )
    {
      double tmpvct[100];
      size_t vctsize = (size_t)IEG_G_NumVCP(gdb);

      for ( size_t i = 0; i < vctsize/2; i++ ) tmpvct[i] = vct[i];
      for ( size_t i = 0; i < vctsize/2; i++ ) tmpvct[i+vctsize/2] = vct[i+50];

      varDefVCT(vctsize, tmpvct);
    }

  int lbounds = IEG_P_LevelType(pdb) == IEG_LTYPE_HYBRID_LAYER ? 1 : 0;

  int datatype = iegInqDatatype(prec);

  int varID, levelID = 0;
  varAddRecord(recID, param, gridID, leveltype, lbounds, level1, level2, 0, 0,
	       datatype, &varID, &levelID, TSTEP_INSTANT, 0, 0, -1,
               NULL, NULL, NULL, NULL, NULL, NULL, 0);

  record->varID   = (short)varID;
  record->levelID = (short)levelID;

  streamptr->tsteps[tsID].nallrecs++;
  streamptr->nrecs++;

  if ( CDI_Debug )
    Message("varID = %d gridID = %d levelID = %d", varID, gridID, levelID);
}

#if 0
static
void iegCmpRecord(stream_t *streamptr, int tsID, int recID, off_t position, int param,
		  int level, size_t xsize, size_t ysize)
{
  int varID = 0;
  int levelID = 0;

  record_t *record  = &streamptr->tsteps[tsID].records[recID];

  if ( param != (*record).param || level != (*record).ilevel )
    Error("inconsistent timestep");

  (*record).position = position;
  /*
  varID   = (*record).varID;
  levelID = (*record).levelID;

  streamptr->vars[varID].level[levelID] = recID;

  streamptr->tsteps[tsID].nallrecs++;
  streamptr->nrecs++;
  */
  if ( CDI_Debug )
    Message("varID = %d levelID = %d", varID, levelID);
}
#endif

static
void iegDateTime(int *pdb, int64_t *date, int *time)
{
  int ryear   = IEG_P_Year(pdb);
  int rmonth  = IEG_P_Month(pdb);
  int rday    = IEG_P_Day(pdb);

  int rhour   = IEG_P_Hour(pdb);
  int rminute = IEG_P_Minute(pdb);

  if ( rminute == -1 ) rminute = 0;

  *date = cdiEncodeDate(ryear, rmonth, rday);
  *time = cdiEncodeTime(rhour, rminute, 0);
}

static
void iegScanTimestep1(stream_t *streamptr)
{
  DateTime datetime0 = { LONG_MIN, LONG_MIN };
  off_t recpos;
  iegcompvar_t compVar, compVar0;
  iegrec_t *iegp = (iegrec_t*) streamptr->record->exsep;

  streamptr->curTsID = 0;

  int tsID = tstepsNewEntry(streamptr);
  if ( tsID != 0 )
    Error("Internal problem! tstepsNewEntry returns %d", tsID);
  taxis_t *taxis = &streamptr->tsteps[tsID].taxis;

  int fileID = streamptr->fileID;

  int nrecs = 0;
  while ( true )
    {
      recpos = fileGetPos(fileID);
      int status = iegRead(fileID, iegp);
      if ( status != 0 )
	{
	  streamptr->ntsteps = 1;
	  break;
	}
      size_t recsize = (size_t)(fileGetPos(fileID) - recpos);

      int prec   = iegp->dprec;
      int rcode  = IEG_P_Parameter(iegp->ipdb);
      int tabnum = IEG_P_CodeTable(iegp->ipdb);
      int param  = cdiEncodeParam(rcode, tabnum, 255);
      int rlevel = (IEG_P_LevelType(iegp->ipdb) == IEG_LTYPE_HYBRID_LAYER) ? IEG_P_Level1(iegp->ipdb) : IEG_P_Level2(iegp->ipdb);

      if ( IEG_P_LevelType(iegp->ipdb) == 100 ) rlevel *= 100;

      int64_t vdate = 0;
      int vtime = 0;
      iegDateTime(iegp->ipdb, &vdate, &vtime);

      if ( nrecs == 0 )
	{
	  datetime0.date = vdate;
	  datetime0.time = vtime;
	}
      else
	{
	  compVar.param = param;
          compVar.level = rlevel;
          int recID = 0;
	  for ( recID = 0; recID < nrecs; recID++ )
	    {
	      compVar0.param = streamptr->tsteps[0].records[recID].param;
	      compVar0.level = streamptr->tsteps[0].records[recID].ilevel;

	      if ( memcmp(&compVar0, &compVar, sizeof(iegcompvar_t)) == 0 ) break;
	    }
	  if ( recID < nrecs ) break;
	  DateTime datetime = { .date = vdate, .time = vtime};
	  if ( datetimeCmp(datetime, datetime0) )
	    Warning("Inconsistent verification time for param %d level %d", param, rlevel);
	}

      nrecs++;

      if ( CDI_Debug )
	Message("%4d%8d%4d%8d%8ld%6d", nrecs, (int)recpos, param, rlevel, (long)vdate, vtime);

      iegAddRecord(streamptr, param, iegp->ipdb, iegp->igdb, iegp->vct, recsize, recpos, prec);
    }

  streamptr->rtsteps = 1;

  cdi_generate_vars(streamptr);

  int taxisID = taxisCreate(TAXIS_ABSOLUTE);
  taxis->type  = TAXIS_ABSOLUTE;
  taxis->vdate = datetime0.date;
  taxis->vtime = (int)datetime0.time;
  taxis->rdate = taxis->vdate;
  taxis->rtime = taxis->vtime;

  int vlistID = streamptr->vlistID;
  vlistDefTaxis(vlistID, taxisID);

  vlist_check_contents(vlistID);

  int nrecords = streamptr->tsteps[0].nallrecs;
  if ( nrecords < streamptr->tsteps[0].recordSize )
    {
      streamptr->tsteps[0].recordSize = nrecords;
      streamptr->tsteps[0].records =
	(record_t *) Realloc(streamptr->tsteps[0].records,
                             (size_t)nrecords * sizeof (record_t));
    }

  streamptr->tsteps[0].recIDs = (int *) Malloc((size_t)nrecords * sizeof (int));
  streamptr->tsteps[0].nrecs = nrecords;
  for ( int recID = 0; recID < nrecords; recID++ )
    streamptr->tsteps[0].recIDs[recID] = recID;

  if ( streamptr->ntsteps == -1 )
    {
      int tsID = tstepsNewEntry(streamptr);
      if ( tsID != streamptr->rtsteps )
	Error("Internal error. tsID = %d", tsID);

      streamptr->tsteps[tsID-1].next   = true;
      streamptr->tsteps[tsID].position = recpos;
    }

  streamScanTimeConstAdjust(streamptr, taxis);
}

static
int iegScanTimestep2(stream_t *streamptr)
{
  off_t recpos = 0;
  iegcompvar_t compVar, compVar0;
  iegrec_t *iegp = (iegrec_t*) streamptr->record->exsep;

  streamptr->curTsID = 1;

  int vlistID = streamptr->vlistID;
  int fileID  = streamptr->fileID;

  int tsID = streamptr->rtsteps;
  if ( tsID != 1 )
    Error("Internal problem! unexpected timestep %d", tsID+1);

  taxis_t *taxis = &streamptr->tsteps[tsID].taxis;

  fileSetPos(fileID, streamptr->tsteps[tsID].position, SEEK_SET);

  cdi_create_records(streamptr, tsID);

  int nrecords = streamptr->tsteps[0].nallrecs;
  streamptr->tsteps[1].recIDs = (int *) Malloc((size_t)nrecords * sizeof(int));
  streamptr->tsteps[1].nrecs = 0;
  for ( int recID = 0; recID < nrecords; recID++ )
    streamptr->tsteps[1].recIDs[recID] = -1;

  for ( int recID = 0; recID < nrecords; recID++ )
    {
      streamptr->tsteps[tsID].records[recID].position =
	streamptr->tsteps[0].records[recID].position;
      streamptr->tsteps[tsID].records[recID].size     =
	streamptr->tsteps[0].records[recID].size;
    }

  for ( int rindex = 0; rindex <= nrecords; rindex++ )
    {
      recpos = fileGetPos(fileID);
      int status = iegRead(fileID, iegp);
      if ( status != 0 )
	{
	  streamptr->ntsteps = 2;
	  break;
	}
      size_t recsize = (size_t)(fileGetPos(fileID) - recpos);

      int rcode  = IEG_P_Parameter(iegp->ipdb);
      int tabnum = IEG_P_CodeTable(iegp->ipdb);
      int param  = cdiEncodeParam(rcode, tabnum, 255);
      int rlevel = (IEG_P_LevelType(iegp->ipdb) == IEG_LTYPE_HYBRID_LAYER) ? IEG_P_Level1(iegp->ipdb) : IEG_P_Level2(iegp->ipdb);

      if ( IEG_P_LevelType(iegp->ipdb) == 100 ) rlevel *= 100;

      int64_t vdate = 0;
      int vtime = 0;
      iegDateTime(iegp->ipdb, &vdate, &vtime);

      if ( rindex == 0 )
	{
	  taxis->type  = TAXIS_ABSOLUTE;
	  taxis->vdate = vdate;
	  taxis->vtime = vtime;
	}

      compVar.param = param;
      compVar.level = rlevel;
      bool nextstep = false;
      int recID = 0;
      for ( recID = 0; recID < nrecords; recID++ )
	{
	  compVar0.param = streamptr->tsteps[tsID].records[recID].param;
	  compVar0.level = streamptr->tsteps[tsID].records[recID].ilevel;

	  if ( memcmp(&compVar0, &compVar, sizeof(iegcompvar_t)) == 0 )
	    {
	      if ( streamptr->tsteps[tsID].records[recID].used )
		{
		  nextstep = true;
		}
	      else
		{
		  streamptr->tsteps[tsID].records[recID].used = true;
		  streamptr->tsteps[tsID].recIDs[rindex] = recID;
		}
	      break;
	    }
	}
      if ( recID == nrecords )
	{
	  char paramstr[32];
	  cdiParamToString(param, paramstr, sizeof(paramstr));
	  Warning("param %s level %d not defined at timestep 1", paramstr, rlevel);
	  return CDI_EUFSTRUCT;
	}

      if ( nextstep ) break;

      if ( CDI_Debug )
	Message("%4d%8d%4d%8d%8ld%6d", rindex+1, (int)recpos, param, rlevel, (long)vdate, vtime);

      streamptr->tsteps[tsID].records[recID].size = recsize;

      compVar0.param = streamptr->tsteps[tsID].records[recID].param;
      compVar0.level = streamptr->tsteps[tsID].records[recID].ilevel;

      if ( memcmp(