/*---------------------------------------------------------------------------
  NeXus - Neutron & X-ray Common Data Format
  
  Application Program Interface Routines
  
  Copyright (C) 1997-2000 Mark Koennecke, Przemek Klosowski
  
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.
 
  This library 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
  Lesser General Public License for more details.
 
  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
  For further information, see <http://www.neutron.anl.gov/NeXus/>

----------------------------------------------------------------------------*/

static const char* rscid = "$Id: napi.c,v 1.9 2005/03/08 11:11:51 zolliker Exp $";	/* Revision interted by CVS */

#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <time.h>
#include "napi.h"

/*
 * We need to include CALLING_STYLE in the function pointer definition
 * or else we get a type mismatch on Win32
 */
  typedef struct {
        NXhandle *pNexusData;   
        NXstatus (CALLING_STYLE *nxclose)(NXhandle* pHandle);
        NXstatus (CALLING_STYLE *nxflush)(NXhandle* pHandle);
        NXstatus (CALLING_STYLE *nxmakegroup) (NXhandle handle, CONSTCHAR *name, char* NXclass);
        NXstatus (CALLING_STYLE *nxopengroup) (NXhandle handle, CONSTCHAR *name, char* NXclass);
        NXstatus (CALLING_STYLE *nxclosegroup)(NXhandle handle);
        NXstatus (CALLING_STYLE *nxmakedata) (NXhandle handle, CONSTCHAR* label, int datatype, int rank, int dim[]);
        NXstatus (CALLING_STYLE *nxcompmakedata) (NXhandle handle, CONSTCHAR* label, int datatype, int rank, int dim[], int comp_typ, int bufsize[]);
        NXstatus (CALLING_STYLE *nxcompress) (NXhandle handle, int compr_type);
        NXstatus (CALLING_STYLE *nxopendata) (NXhandle handle, CONSTCHAR* label);
        NXstatus (CALLING_STYLE *nxclosedata)(NXhandle handle);
        NXstatus (CALLING_STYLE *nxputdata)(NXhandle handle, void* data);
        NXstatus (CALLING_STYLE *nxputattr)(NXhandle handle, CONSTCHAR* name, void* data, int iDataLen, int iType);
        NXstatus (CALLING_STYLE *nxputslab)(NXhandle handle, void* data, int start[], int size[]);    
        NXstatus (CALLING_STYLE *nxgetdataID)(NXhandle handle, NXlink* pLink);
        NXstatus (CALLING_STYLE *nxmakelink)(NXhandle handle, NXlink* pLink);
        NXstatus (CALLING_STYLE *nxgetdata)(NXhandle handle, void* data);
        NXstatus (CALLING_STYLE *nxgetinfo)(NXhandle handle, int* rank, int dimension[], int* datatype);
        NXstatus (CALLING_STYLE *nxgetnextentry)(NXhandle handle, NXname name, NXname nxclass, int* datatype);
        NXstatus (CALLING_STYLE *nxgetslab)(NXhandle handle, void* data, int start[], int size[]);
        NXstatus (CALLING_STYLE *nxgetnextattr)(NXhandle handle, NXname pName, int *iLength, int *iType);
        NXstatus (CALLING_STYLE *nxgetattr)(NXhandle handle, char* name, void* data, int* iDataLen, int* iType);
        NXstatus (CALLING_STYLE *nxgetattrinfo)(NXhandle handle, int* no_items);
        NXstatus (CALLING_STYLE *nxgetgroupID)(NXhandle handle, NXlink* pLink);
        NXstatus (CALLING_STYLE *nxgetgroupinfo)(NXhandle handle, int* no_items, NXname name, NXname nxclass);
        NXstatus (CALLING_STYLE *nxsameID)(NXhandle handle, NXlink* pFirstID, NXlink* pSecondID);
        NXstatus (CALLING_STYLE *nxinitgroupdir)(NXhandle handle);
        NXstatus (CALLING_STYLE *nxinitattrdir)(NXhandle handle);
  } NexusFunction, *pNexusFunction;
  
  static int iFortifyScope;
/*------------------------------------------------------------------------
  HDF-5 cache size special stuff
  -------------------------------------------------------------------------*/
long nx_cacheSize =  1024000; /* 1MB, HDF-5 default */

NXstatus CALLING_STYLE NXsetcache(long newVal)
{
  if(newVal > 0)
  {
    nx_cacheSize = newVal;
    return NX_OK;
  }
  return NX_ERROR;
}
 

   /*---------------------------------------------------------------------*/

  void NXNXNXReportError(void *pData, char *string)
  {
    printf("%s \n",string);
  }
     
  /*---------------------------------------------------------------------*/

  void *NXpData = NULL;
  void (*NXIReportError)(void *pData, char *string) = NXNXNXReportError;

  /*---------------------------------------------------------------------*/

  NX_EXTERNAL void CALLING_STYLE NXMSetError(void *pData, void (*NewError)(void *pD, char *text))
  {
    NXpData = pData;
    NXIReportError = NewError;
  }
  
#ifdef HDF5
#include "napi5.h"
#endif
#ifdef HDF4
#include "napi4.h"
#endif
  

  /* ---------------------------------------------------------------------- 
  
                          Definition of NeXus API

   ---------------------------------------------------------------------*/


  NXstatus CALLING_STYLE  NXopen(CONSTCHAR *filename, NXaccess am, NXhandle *gHandle)
  {
    int hdf_type=0;
    int iRet=0;
    NXhandle hdf5_handle;
    NXhandle hdf4_handle;
    pNexusFunction fHandle;
    NXstatus retstat;
        
    /* configure fortify 
    iFortifyScope = Fortify_EnterScope();
    Fortify_CheckAllMemory();
    */

    fHandle = (pNexusFunction)malloc(sizeof(NexusFunction));
    if (fHandle == NULL) {
      NXIReportError (NXpData,"ERROR: no memory to create Function structure");
      return NX_ERROR;
    }
    if (am==NXACC_CREATE) {
      /* HDF4 will be used ! */
      hdf_type=1;
    } else if (am==NXACC_CREATE4) {
      /* HDF4 will be used ! */
      hdf_type=1;   
    } else if (am==NXACC_CREATE5) {
      /* HDF5 will be used ! */
      hdf_type=2;   
    } else {
      /* check file type hdf4/hdf5 for reading */
#ifdef HDF5
      iRet=H5Fis_hdf5((const char*)filename);
#endif
      if (iRet>0) {
        hdf_type=2; 
      } else {
#ifdef HDF4
        iRet=Hishdf((const char*)filename);
#endif
        if (iRet>0) {
          hdf_type=1; 
        } 
      }
    }
    if (hdf_type==1) {
      /* HDF4 type */
#ifdef HDF4
      retstat = NX4open((const char *)filename,am,&hdf4_handle);
      if(retstat != NX_OK){
	free(fHandle);
	return retstat;
      }
      fHandle->pNexusData=hdf4_handle;
      fHandle->nxclose=NX4close;
      fHandle->nxflush=NX4flush;
      fHandle->nxmakegroup=NX4makegroup;
      fHandle->nxopengroup=NX4opengroup;
      fHandle->nxclosegroup=NX4closegroup;
      fHandle->nxmakedata=NX4makedata;
      fHandle->nxcompmakedata=NX4compmakedata;
      fHandle->nxcompress=NX4compress;
      fHandle->nxopendata=NX4opendata;
      fHandle->nxclosedata=NX4closedata;
      fHandle->nxputdata=NX4putdata;
      fHandle->nxputattr=NX4putattr;
      fHandle->nxputslab=NX4putslab;    
      fHandle->nxgetdataID=NX4getdataID;
      fHandle->nxmakelink=NX4makelink;
      fHandle->nxgetdata=NX4getdata;
      fHandle->nxgetinfo=NX4getinfo;
      fHandle->nxgetnextentry=NX4getnextentry;
      fHandle->nxgetslab=NX4getslab;
      fHandle->nxgetnextattr=NX4getnextattr;
      fHandle->nxgetattr=NX4getattr;
      fHandle->nxgetattrinfo=NX4getattrinfo;
      fHandle->nxgetgroupID=NX4getgroupID;
      fHandle->nxgetgroupinfo=NX4getgroupinfo;
      fHandle->nxsameID=NX4sameID;
      fHandle->nxinitgroupdir=NX4initgroupdir;
      fHandle->nxinitattrdir=NX4initattrdir;
      *gHandle = fHandle;
#else
      NXIReportError (NXpData,"ERROR: Attempt to create HDF4 file when not linked with HDF4");
      *gHandle = NULL;
      retstat = NX_ERROR;
#endif /* HDF4 */
      return retstat; 
    } else if (hdf_type==2) {
      /* HDF5 type */
#ifdef HDF5
      retstat = NX5open(filename,am,&hdf5_handle);
      if(retstat != NX_OK){
	free(fHandle);
	return retstat;
      }
      fHandle->pNexusData=hdf5_handle;
      fHandle->nxclose=NX5close;
      fHandle->nxflush=NX5flush;
      fHandle->nxmakegroup=NX5makegroup;
      fHandle->nxopengroup=NX5opengroup;
      fHandle->nxclosegroup=NX5closegroup;
      fHandle->nxmakedata=NX5makedata;
      fHandle->nxcompmakedata=NX5compmakedata;
      fHandle->nxcompress=NX5compress;
      fHandle->nxopendata=NX5opendata;
      fHandle->nxclosedata=NX5closedata;
      fHandle->nxputdata=NX5putdata;
      fHandle->nxputattr=NX5putattr;
      fHandle->nxputslab=NX5putslab;    
      fHandle->nxgetdataID=NX5getdataID;
      fHandle->nxmakelink=NX5makelink;
      fHandle->nxgetdata=NX5getdata;
      fHandle->nxgetinfo=NX5getinfo;
      fHandle->nxgetnextentry=NX5getnextentry;
      fHandle->nxgetslab=NX5getslab;
      fHandle->nxgetnextattr=NX5getnextattr;
      fHandle->nxgetattr=NX5getattr;
      fHandle->nxgetattrinfo=NX5getattrinfo;
      fHandle->nxgetgroupID=NX5getgroupID;
      fHandle->nxgetgroupinfo=NX5getgroupinfo;
      fHandle->nxsameID=NX5sameID;
      fHandle->nxinitgroupdir=NX5initgroupdir;
      fHandle->nxinitattrdir=NX5initattrdir;
      *gHandle = fHandle;
#else
      NXIReportError (NXpData,"ERROR: Attempt to create HDF5 file when not linked with HDF5");
      *gHandle = NULL;
      retstat = NX_ERROR;
#endif /* HDF5 */
      return retstat;
    } else {
      NXIReportError (NXpData,
          "ERROR: Format not readable by this NeXus library");
      *gHandle = NULL;
      return NX_ERROR;
    }
  }

/* ------------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXclose (NXhandle *fid)
  { 
    NXhandle hfil; 
    int status;
   
    pNexusFunction pFunc=NULL;
    pFunc = (pNexusFunction)*fid;
    hfil = pFunc->pNexusData;
    status =  pFunc->nxclose(&hfil);
    pFunc->pNexusData = hfil;
    free(pFunc);
    /* 
    Fortify_CheckAllMemory();
    */
    return status;   
  }

  /*-----------------------------------------------------------------------*/   

  NXstatus CALLING_STYLE NXmakegroup (NXhandle fid, CONSTCHAR *name, char *nxclass) 
  {
     pNexusFunction pFunc = (pNexusFunction)fid;
     return pFunc->nxmakegroup(pFunc->pNexusData, name, nxclass);   
  }

  /*------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXopengroup (NXhandle fid, CONSTCHAR *name, char *nxclass)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxopengroup(pFunc->pNexusData, name, nxclass);  
  } 

  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXclosegroup (NXhandle fid)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxclosegroup(pFunc->pNexusData);  
  }   

  /* --------------------------------------------------------------------- */
  
  NXstatus CALLING_STYLE NXmakedata (NXhandle fid, CONSTCHAR *name, int datatype, 
                                  int rank, int dimensions[])
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxmakedata(pFunc->pNexusData, name, datatype, rank, dimensions); 
  }


 /* --------------------------------------------------------------------- */
  
  NXstatus CALLING_STYLE NXcompmakedata (NXhandle fid, CONSTCHAR *name, int datatype, 
                           int rank, int dimensions[],int compress_type, int chunk_size[])
  {
    pNexusFunction pFunc = (pNexusFunction)fid; 
    return pFunc->nxcompmakedata (pFunc->pNexusData, name, datatype, rank, dimensions, compress_type, chunk_size); 
  } 
  
 
  /* --------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXcompress (NXhandle fid, int compress_type)
  {
    pNexusFunction pFunc = (pNexusFunction)fid; 
    return pFunc->nxcompress (pFunc->pNexusData, compress_type); 
  }
  
 
  /* --------------------------------------------------------------------- */
  
  NXstatus CALLING_STYLE NXopendata (NXhandle fid, CONSTCHAR *name)
  {
    pNexusFunction pFunc = (pNexusFunction)fid; 
    return pFunc->nxopendata(pFunc->pNexusData, name); 
  } 


  /* ----------------------------------------------------------------- */
    
  NXstatus CALLING_STYLE NXclosedata (NXhandle fid)
  { 
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxclosedata(pFunc->pNexusData);
  }

  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXputdata (NXhandle fid, void *data)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxputdata(pFunc->pNexusData, data);
  }

  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXputattr (NXhandle fid, CONSTCHAR *name, void *data, 
                                  int datalen, int iType)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxputattr(pFunc->pNexusData, name, data, datalen, iType);
  }

  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXputslab (NXhandle fid, void *data, int iStart[], int iSize[])
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxputslab(pFunc->pNexusData, data, iStart, iSize);
  }

  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXgetdataID (NXhandle fid, NXlink* sRes)
  {  
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetdataID(pFunc->pNexusData, sRes);
  }


  /* ------------------------------------------------------------------- */

  NXstatus CALLING_STYLE NXmakelink (NXhandle fid, NXlink* sLink)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxmakelink(pFunc->pNexusData, sLink);
  }

  
  /*----------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXflush(NXhandle *pHandle)
  {
    NXhandle hfil; 
    int status;
   
    pNexusFunction pFunc=NULL;
    pFunc = (pNexusFunction)*pHandle;
    hfil = pFunc->pNexusData;
    status =  pFunc->nxflush(&hfil);
    pFunc->pNexusData = hfil;
    return status; 
  }


  /*-------------------------------------------------------------------------*/
  
  NXstatus CALLING_STYLE NXmalloc (void** data, int rank, int dimensions[], int datatype)
  {
    int i;
    size_t size = 1;
    *data = NULL;
    for(i=0; i<rank; i++)
    size *= dimensions[i];
    if ((datatype == NX_CHAR) || (datatype == NX_INT8) || (datatype == NX_UINT8)) {
        /* size is correct already */
      }
      else if ((datatype == NX_INT16) || (datatype == NX_UINT16)) {
      size *= 2;
      }    
      else if ((datatype == NX_INT32) || (datatype == NX_UINT32) || (datatype == NX_FLOAT32)) {
        size *= 4;
      }    
      else if (datatype == NX_FLOAT64) {
        size *= 8;
      }
      else {
        NXIReportError (NXpData, "ERROR: NXmalloc - unknown data type in array");
        return NX_ERROR;
    }
    *data = (void*)malloc(size);
     memset(*data,0,size);
    return NX_OK;
  }
    
  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXfree (void** data)
  {
    if (data == NULL) {
       NXIReportError (NXpData, "ERROR: passing NULL to NXfree");
       return NX_ERROR;
    }
    if (*data == NULL) {
       NXIReportError (NXpData,"ERROR: passing already freed pointer to NXfree");
       return NX_ERROR;
    }
    free(*data);
    *data = NULL;
    return NX_OK;
  }

  /* --------------------------------------------------------------------- */
           
 
  NXstatus CALLING_STYLE NXgetnextentry (NXhandle fid, NXname name, NXname nxclass, int *datatype)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetnextentry(pFunc->pNexusData, name, nxclass, datatype);  
  }


  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetdata (NXhandle fid, void *data)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetdata(pFunc->pNexusData, data); 
  }
  
    
  /*-------------------------------------------------------------------------*/
 
  NXstatus CALLING_STYLE NXgetinfo (NXhandle fid, int *rank, int dimension[], int *iType)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetinfo(pFunc->pNexusData, rank, dimension, iType);
  }
  
  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetslab (NXhandle fid, void *data, int iStart[], int iSize[])
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetslab(pFunc->pNexusData, data, iStart, iSize);
  }
  
  
  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetnextattr (NXhandle fileid, NXname pName,
                                     int *iLength, int *iType)
  {
    pNexusFunction pFunc = (pNexusFunction)fileid;
    return pFunc->nxgetnextattr(pFunc->pNexusData, pName, iLength, iType);  
  }
 

  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetattr (NXhandle fid, char *name, void *data, int* datalen, int* iType)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetattr(pFunc->pNexusData, name, data, datalen, iType);  
  }


  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetattrinfo (NXhandle fid, int *iN)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetattrinfo(pFunc->pNexusData, iN);  
  }


  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetgroupID (NXhandle fileid, NXlink* sRes)
  {
    pNexusFunction pFunc = (pNexusFunction)fileid;
    return pFunc->nxgetgroupID(pFunc->pNexusData, sRes);  
  }

  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXgetgroupinfo (NXhandle fid, int *iN, NXname pName, NXname pClass)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxgetgroupinfo(pFunc->pNexusData, iN, pName, pClass);  
  }

  
  /*-------------------------------------------------------------------------*/

  NXstatus CALLING_STYLE NXsameID (NXhandle fileid, NXlink* pFirstID, NXlink* pSecondID)
  {
    pNexusFunction pFunc = (pNexusFunction)fileid;
    return pFunc->nxsameID(pFunc->pNexusData, pFirstID, pSecondID);  
  }

  /*-------------------------------------------------------------------------*/
  
  NXstatus CALLING_STYLE NXinitattrdir (NXhandle fid)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxinitattrdir(pFunc->pNexusData);
  }
  
  
  /*-------------------------------------------------------------------------*/
 
  NXstatus CALLING_STYLE NXinitgroupdir (NXhandle fid)
  {
    pNexusFunction pFunc = (pNexusFunction)fid;
    return pFunc->nxinitgroupdir(pFunc->pNexusData);
  }
/*------------------------------------------------------------------------
  Implementation of NXopenpath. 
  --------------------------------------------------------------------------*/
static int isDataSetOpen(NXhandle hfil)
{
  NXlink id;
  
  /*
    This uses the (sensible) feauture that NXgetdataID returns NX_ERROR
    when no dataset is open
  */
  if(NXgetdataID(hfil,&id) == NX_ERROR)
  {
    return 0;
  }
  else 
  {
    return 1;
  }
}
/*----------------------------------------------------------------------*/
static int isRoot(NXhandle hfil)
{
  NXlink id;
  
  /*
    This uses the feauture that NXgetgroupID returns NX_ERROR
    when we are at root level
  */
  if(NXgetgroupID(hfil,&id) == NX_ERROR)
  {
    return 1;
  }
  else 
  {
    return 0;
  }
}
/*--------------------------------------------------------------------
  copies the next path element into element.
  returns a pointer into path beyond the extracted path
  ---------------------------------------------------------------------*/
static char *extractNextPath(char *path, NXname element)
{
  char *pPtr, *pStart;
  int length;

  pPtr = path;
  /*
    skip over leading /
  */
  if(*pPtr == '/')
  {
    pPtr++;
  }
  pStart = pPtr;
  
  /*
    find next /
  */
  pPtr = strchr(pStart,'/');
  if(pPtr == NULL)
  {
    /*
      this is the last path element
    */
    strcpy(element,pStart);
    return NULL;
  } else {
    length = pPtr - pStart;
    strncpy(element,pStart,length);
    element[length] = '\0';
  }
  return pPtr + 1;
}
/*-------------------------------------------------------------------*/
static NXstatus gotoRoot(NXhandle hfil)
{
    int status;

    if(isDataSetOpen(hfil))
    {
      status = NXclosedata(hfil);
      if(status == NX_ERROR)
      {
	return status;
      }
    }
    while(!isRoot(hfil))
    {
      status = NXclosegroup(hfil);
      if(status == NX_ERROR)
      {
	return status;
      }
    }
    return NX_OK;
}
/*--------------------------------------------------------------------*/
static int isRelative(char *path)
{
  if(path[0] == '.' && path[1] == '.')
    return 1;
  else
    return 0;
}
/*------------------------------------------------------------------*/
static NXstatus moveOneDown(NXhandle hfil)
{
  if(isDataSetOpen(hfil))
  {
    return NXclosedata(hfil);
  } 
  else
  {
    return NXclosegroup(hfil);
  }
}
/*-------------------------------------------------------------------
  returns a pointer to the remaining path string to move up
  --------------------------------------------------------------------*/
static char *moveDown(NXhandle hfil, char *path, int *code)
{
  int status;
  NXname pathElem;
  char *pPtr;

  *code = NX_OK;

  if(path[0] == '/')
  {
    *code = gotoRoot(hfil);
    return path;
  } 
  else 
  {
    pPtr = path;
    while(isRelative(pPtr))
    {
      status = moveOneDown(hfil);
      if(status == NX_ERROR)
      {
	*code = status;
	return pPtr;
      }
      pPtr += 3;
    }
    return pPtr;
  }
} 
/*--------------------------------------------------------------------*/
static NXstatus stepOneUp(NXhandle hfil, char *name)
{
  int status, datatype;
  NXname name2, xclass;
  char pBueffel[256];  

  /*
    catch the case when we are there: i.e. no further stepping
    necessary. This can happen with paths like ../
  */
  if(strlen(name) < 1)
  {
      return NX_OK;
  }
  
  NXinitgroupdir(hfil);
  while(NXgetnextentry(hfil,name2,xclass,&datatype) != NX_EOD)
  {
    
    if(strcmp(name2,name) == 0)
    {
      if(strcmp(xclass,"SDS") == 0)
      {
	return NXopendata(hfil,name);
      } 
      else
      {
	return NXopengroup(hfil,name,xclass);
      }
    }
  }
  snprintf(pBueffel,255,"ERROR: NXopenpath cannot step into %s",name);
  NXIReportError (NXpData, pBueffel);
  return NX_ERROR;              
}
/*---------------------------------------------------------------------*/
NXstatus CALLING_STYLE NXopenpath(NXhandle hfil, CONSTCHAR *path)
{
  int status, run = 1;
  NXname pathElement;
  char *pPtr;

  if(hfil == NULL || path == NULL)
  {
    NXIReportError(NXpData,
     "ERROR: NXopendata needs both a file handle and a path string");
    return NX_ERROR;
  }

  pPtr = moveDown(hfil,(char *)path,&status);
  if(status != NX_OK)
  {
    NXIReportError (NXpData, 
		    "ERROR: NXopendata failed to move down in hierarchy");
    return status;
  }

  while(run == 1)
  {
    pPtr = extractNextPath(pPtr, pathElement);
    status = stepOneUp(hfil,pathElement);
    if(status != NX_OK)
    {
      return status;
    }
    if(pPtr == NULL)
    {
      run = 0;
    }
  }
  return NX_OK;
}
/*----------------------------------------------------------------------
                 F77 - API - Support - Routines
  ----------------------------------------------------------------------*/
  /*
   * We store the whole of the NeXus file in the array - that way
   * we can just pass the array name to C as it will be a valid
   * NXhandle. We could store the NXhandle value in the FORTRAN array
   * instead, but that would mean writing far more wrappers
   */
  NXstatus CALLING_STYLE NXfopen(char * filename, NXaccess* am, 
                                 NexusFunction* pHandle)
  {
	NXstatus ret;
 	NXhandle fileid = NULL;
	ret = NXopen(filename, *am, &fileid);
	if (ret == NX_OK)
	{
	    memcpy(pHandle, fileid, sizeof(NexusFunction));
	}
	else
	{
	    memset(pHandle, 0, sizeof(NexusFunction));
	}
	if (fileid != NULL)
	{
	    free(fileid);
	}
	return ret;
  }
/* 
 * The pHandle from FORTRAN is a pointer to a static FORTRAN
 * array holding the NexusFunction structure. We need to malloc()
 * a temporary copy as NXclose will try to free() this
 */
  NXstatus CALLING_STYLE NXfclose (NexusFunction* pHandle)
  {
    NXhandle h;
    NXstatus ret;
    h = (NXhandle)malloc(sizeof(NexusFunction));
    memcpy(h, pHandle, sizeof(NexusFunction));
    ret = NXclose(&h);		/* does free(h) */
    memset(pHandle, 0, sizeof(NexusFunction));
    return ret;
  }
  
/*---------------------------------------------------------------------*/  
  NXstatus CALLING_STYLE NXfflush(NexusFunction* pHandle)
  {
    NXhandle h;
    NXstatus ret;
    h = (NXhandle)malloc(sizeof(NexusFunction));
    memcpy(h, pHandle, sizeof(NexusFunction));
    ret = NXflush(&h);		/* modifies and reallocates h */
    memcpy(pHandle, h, sizeof(NexusFunction));
    return ret;
  }
/*----------------------------------------------------------------------*/
  NXstatus CALLING_STYLE NXfmakedata(NXhandle fid, char *name, int *pDatatype,
		int *pRank, int dimensions[])
  {
    NXstatus ret;
    static char buffer[256];
    int i, *reversed_dimensions;
    reversed_dimensions = (int*)malloc(*pRank * sizeof(int));
    if (reversed_dimensions == NULL)
    {
        sprintf (buffer, 
        "ERROR: Cannot allocate space for array rank of %d in NXfmakedata", 
                *pRank);
        NXIReportError (NXpData, buffer);
	return NX_ERROR;
    }
/*
 * Reverse dimensions array as FORTRAN is column major, C row major
 */
    for(i=0; i < *pRank; i++)
    {
	reversed_dimensions[i] = dimensions[*pRank - i - 1];
    }
    ret = NXmakedata(fid, name, *pDatatype, *pRank, reversed_dimensions);
    free(reversed_dimensions);
    return ret;
  }


  NXstatus CALLING_STYLE NXfcompmakedata(NXhandle fid, char *name, 
                int *pDatatype,
		int *pRank, int dimensions[],
                int *compression_type, int chunk[])
  {
    NXstatus ret;
    static char buffer[256];
    int i, *reversed_dimensions, *reversed_chunk;
    reversed_dimensions = (int*)malloc(*pRank * sizeof(int));
    reversed_chunk = (int*)malloc(*pRank * sizeof(int));
    if (reversed_dimensions == NULL || reversed_chunk == NULL)
    {
        sprintf (buffer, 
      "ERROR: Cannot allocate space for array rank of %d in NXfcompmakedata", 
         *pRank);
        NXIReportError (NXpData, buffer);
	return NX_ERROR;
    }
/*
 * Reverse dimensions array as FORTRAN is column major, C row major
 */
    for(i=0; i < *pRank; i++)
    {
	reversed_dimensions[i] = dimensions[*pRank - i - 1];
	reversed_chunk[i] = chunk[*pRank - i - 1];
    }
    ret = NXcompmakedata(fid, name, *pDatatype, *pRank, 
        reversed_dimensions,*compression_type, reversed_chunk);
    free(reversed_dimensions);
    free(reversed_chunk);
    return ret;
  }
/*-----------------------------------------------------------------------*/
  NXstatus CALLING_STYLE NXfcompress(NXhandle fid, int *compr_type)
  { 
      return NXcompress(fid,*compr_type);
  }
/*-----------------------------------------------------------------------*/
  NXstatus CALLING_STYLE NXfputattr(NXhandle fid, char *name, void *data, 
                                   int *pDatalen, int *pIType)
  {
    return NXputattr(fid, name, data, *pDatalen, *pIType);
  }