示例#1
0
GDALDataset *HDF4Dataset::Open( GDALOpenInfo * poOpenInfo )

{
    int32	i;

    if( !Identify( poOpenInfo ) )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Try opening the dataset.                                        */
/* -------------------------------------------------------------------- */
    int32	hHDF4;
    
    hHDF4 = Hopen(poOpenInfo->pszFilename, DFACC_READ, 0);
    
    if( hHDF4 <= 0 )
        return( NULL );

    Hclose( hHDF4 );

/* -------------------------------------------------------------------- */
/*      Create a corresponding GDALDataset.                             */
/* -------------------------------------------------------------------- */
    HDF4Dataset *poDS;

    poDS = new HDF4Dataset();

    poDS->fp = poOpenInfo->fp;
    poOpenInfo->fp = NULL;
    
/* -------------------------------------------------------------------- */
/*          Open HDF SDS Interface.                                     */
/* -------------------------------------------------------------------- */
    poDS->hSD = SDstart( poOpenInfo->pszFilename, DFACC_READ );

    if ( poDS->hSD == -1 )
    {
	delete poDS;
        return NULL;
    }
   
/* -------------------------------------------------------------------- */
/*		Now read Global Attributes.				*/
/* -------------------------------------------------------------------- */
    if ( poDS->ReadGlobalAttributes( poDS->hSD ) != CE_None )
    {
	delete poDS;
        return NULL;
    }

    poDS->SetMetadata( poDS->papszGlobalMetadata, "" );

/* -------------------------------------------------------------------- */
/*		Determine type of file we read.				*/
/* -------------------------------------------------------------------- */
    const char	*pszValue;
    
    if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                       "Signature"))
	 && EQUAL( pszValue, pszGDALSignature ) )
    {
	poDS->iSubdatasetType = H4ST_GDAL;
	poDS->pszSubdatasetType = "GDAL_HDF4";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata, "Title"))
	 && EQUAL( pszValue, "SeaWiFS Level-1A Data" ) )
    {
	poDS->iSubdatasetType = H4ST_SEAWIFS_L1A;
	poDS->pszSubdatasetType = "SEAWIFS_L1A";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata, "Title"))
	&& EQUAL( pszValue, "SeaWiFS Level-2 Data" ) )
    {
	poDS->iSubdatasetType = H4ST_SEAWIFS_L2;
	poDS->pszSubdatasetType = "SEAWIFS_L2";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata, "Title"))
	&& EQUAL( pszValue, "SeaWiFS Level-3 Standard Mapped Image" ) )
    {
	poDS->iSubdatasetType = H4ST_SEAWIFS_L3;
	poDS->pszSubdatasetType = "SEAWIFS_L3";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                            "L1 File Generated By"))
	&& EQUALN( pszValue, "HYP version ", 12 ) )
    {
	poDS->iSubdatasetType = H4ST_HYPERION_L1;
	poDS->pszSubdatasetType = "HYPERION_L1";
    }

    else
    {
	poDS->iSubdatasetType = H4ST_UNKNOWN;
	poDS->pszSubdatasetType = "UNKNOWN";
    }

/* -------------------------------------------------------------------- */
/*  If we have HDF-EOS dataset, process it here.	                */
/* -------------------------------------------------------------------- */
    char	szName[VSNAMELENMAX + 1], szTemp[8192];
    char	*pszString;
    const char  *pszName;
    int		nCount;
    int32	aiDimSizes[H4_MAX_VAR_DIMS];
    int32	iRank, iNumType, nAttrs;
    bool        bIsHDF = true;
    
    // Sometimes "HDFEOSVersion" attribute is not defined and we will
    // determine HDF-EOS datasets using other records
    // (see ReadGlobalAttributes() method).
    if ( poDS->bIsHDFEOS
         || CSLFetchNameValue(poDS->papszGlobalMetadata, "HDFEOSVersion") )
    {
        bIsHDF  = false;

        int32   nSubDatasets, nStrBufSize;

/* -------------------------------------------------------------------- */
/*  Process swath layers.                                               */
/* -------------------------------------------------------------------- */
        hHDF4 = SWopen( poOpenInfo->pszFilename, DFACC_READ );
        if( hHDF4 < 0)
        {
            delete poDS;
            CPLError( CE_Failure, CPLE_OpenFailed, "Failed to open HDF4 `%s'.\n", poOpenInfo->pszFilename );
            return NULL;
        } 
        nSubDatasets = SWinqswath(poOpenInfo->pszFilename, NULL, &nStrBufSize);
#if DEBUG
        CPLDebug( "HDF4", "Number of HDF-EOS swaths: %d", (int)nSubDatasets );
#endif
        if ( nSubDatasets > 0 && nStrBufSize > 0 )
        {
            char    *pszSwathList;
            char    **papszSwaths;

            pszSwathList = (char *)CPLMalloc( nStrBufSize + 1 );
            SWinqswath( poOpenInfo->pszFilename, pszSwathList, &nStrBufSize );
            pszSwathList[nStrBufSize] = '\0';

#if DEBUG
            CPLDebug( "HDF4", "List of HDF-EOS swaths: %s", pszSwathList );
#endif

            papszSwaths =
                CSLTokenizeString2( pszSwathList, ",", CSLT_HONOURSTRINGS );
            CPLFree( pszSwathList );

            if ( nSubDatasets != CSLCount(papszSwaths) )
            {
                CSLDestroy( papszSwaths );
                delete poDS;
                CPLDebug( "HDF4", "Can not parse list of HDF-EOS grids." );
                return NULL;
            }

            for ( i = 0; i < nSubDatasets; i++)
            {
                char    *pszFieldList;
                char    **papszFields;
                int32   *paiRank, *paiNumType;
                int32   hSW, nFields, j;

                hSW = SWattach( hHDF4, papszSwaths[i] );

                nFields = SWnentries( hSW, HDFE_NENTDFLD, &nStrBufSize );
                pszFieldList = (char *)CPLMalloc( nStrBufSize + 1 );
                paiRank = (int32 *)CPLMalloc( nFields * sizeof(int32) );
                paiNumType = (int32 *)CPLMalloc( nFields * sizeof(int32) );

                SWinqdatafields( hSW, pszFieldList, paiRank, paiNumType );

#if DEBUG
                {
                    char *pszTmp =
                        SPrintArray( GDT_UInt32, paiRank, nFields, "," );

                    CPLDebug( "HDF4", "Number of data fields in swath %d: %d",
                              (int) i, (int) nFields );
                    CPLDebug( "HDF4", "List of data fields in swath %d: %s",
                              (int) i, pszFieldList );
                    CPLDebug( "HDF4", "Data fields ranks: %s", pszTmp );

                    CPLFree( pszTmp );
                }
#endif

                papszFields = CSLTokenizeString2( pszFieldList, ",",
                                                  CSLT_HONOURSTRINGS );
                
                for ( j = 0; j < nFields; j++ )
                {
                    SWfieldinfo( hSW, papszFields[j], &iRank, aiDimSizes,
                                 &iNumType, NULL );

                    if ( iRank < 2 )
                        continue;

	            // Add field to the list of GDAL subdatasets
                    nCount = CSLCount( poDS->papszSubDatasets ) / 2;
                    sprintf( szTemp, "SUBDATASET_%d_NAME", nCount + 1 );
	            // We will use the field index as an identificator.
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                CPLSPrintf("HDF4_EOS:EOS_SWATH:\"%s\":%s:%s",
                                           poOpenInfo->pszFilename,
                                           papszSwaths[i], papszFields[j]) );

                    sprintf( szTemp, "SUBDATASET_%d_DESC", nCount + 1 );
                    pszString = SPrintArray( GDT_UInt32, aiDimSizes,
                                             iRank, "x" );
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                         CPLSPrintf( "[%s] %s %s (%s)", pszString,
                                         papszFields[j],
                                         papszSwaths[i],
                                         poDS->GetDataTypeName(iNumType) ) );
                    CPLFree( pszString );
                }

                CSLDestroy( papszFields );
                CPLFree( paiNumType );
                CPLFree( paiRank );
                CPLFree( pszFieldList );
                SWdetach( hSW );
            }

            CSLDestroy( papszSwaths );
        }
        SWclose( hHDF4 );

/* -------------------------------------------------------------------- */
/*  Process grid layers.                                                */
/* -------------------------------------------------------------------- */
        hHDF4 = GDopen( poOpenInfo->pszFilename, DFACC_READ );
        nSubDatasets = GDinqgrid( poOpenInfo->pszFilename, NULL, &nStrBufSize );
#if DEBUG
        CPLDebug( "HDF4", "Number of HDF-EOS grids: %d", (int)nSubDatasets );
#endif
        if ( nSubDatasets > 0 && nStrBufSize > 0 )
        {
            char    *pszGridList;
            char    **papszGrids;

            pszGridList = (char *)CPLMalloc( nStrBufSize + 1 );
            GDinqgrid( poOpenInfo->pszFilename, pszGridList, &nStrBufSize );

#if DEBUG
            CPLDebug( "HDF4", "List of HDF-EOS grids: %s", pszGridList );
#endif

            papszGrids =
                CSLTokenizeString2( pszGridList, ",", CSLT_HONOURSTRINGS );
            CPLFree( pszGridList );

            if ( nSubDatasets != CSLCount(papszGrids) )
            {
                CSLDestroy( papszGrids );
                delete poDS;
                CPLDebug( "HDF4", "Can not parse list of HDF-EOS grids." );
                return NULL;
            }

            for ( i = 0; i < nSubDatasets; i++)
            {
                char    *pszFieldList;
                char    **papszFields;
                int32   *paiRank, *paiNumType;
                int32   hGD, nFields, j;

                hGD = GDattach( hHDF4, papszGrids[i] );

                nFields = GDnentries( hGD, HDFE_NENTDFLD, &nStrBufSize );
                pszFieldList = (char *)CPLMalloc( nStrBufSize + 1 );
                paiRank = (int32 *)CPLMalloc( nFields * sizeof(int32) );
                paiNumType = (int32 *)CPLMalloc( nFields * sizeof(int32) );

                GDinqfields( hGD, pszFieldList, paiRank, paiNumType );

#if DEBUG
                {
                    char* pszTmp =
                            SPrintArray( GDT_UInt32, paiRank, nFields, "," );
                    CPLDebug( "HDF4", "Number of fields in grid %d: %d",
                            (int) i, (int) nFields );
                    CPLDebug( "HDF4", "List of fields in grid %d: %s",
                            (int) i, pszFieldList );
                    CPLDebug( "HDF4", "Fields ranks: %s",
                            pszTmp );
                    CPLFree( pszTmp );
                }
#endif

                papszFields = CSLTokenizeString2( pszFieldList, ",",
                                                  CSLT_HONOURSTRINGS );
                
                for ( j = 0; j < nFields; j++ )
                {
                    GDfieldinfo( hGD, papszFields[j], &iRank, aiDimSizes,
                                 &iNumType, NULL );

                    if ( iRank < 2 )
                        continue;

	            // Add field to the list of GDAL subdatasets
                    nCount = CSLCount( poDS->papszSubDatasets ) / 2;
                    sprintf( szTemp, "SUBDATASET_%d_NAME", nCount + 1 );
	            // We will use the field index as an identificator.
                    poDS->papszSubDatasets =
                        CSLSetNameValue(poDS->papszSubDatasets, szTemp,
                                CPLSPrintf( "HDF4_EOS:EOS_GRID:\"%s\":%s:%s",
                                            poOpenInfo->pszFilename,
                                            papszGrids[i], papszFields[j]));

                    sprintf( szTemp, "SUBDATASET_%d_DESC", nCount + 1 );
                    pszString = SPrintArray( GDT_UInt32, aiDimSizes,
                                             iRank, "x" );
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                         CPLSPrintf("[%s] %s %s (%s)", pszString,
                                             papszFields[j],
                                             papszGrids[i],
                                             poDS->GetDataTypeName(iNumType)) );
                    CPLFree( pszString );
                }

                CSLDestroy( papszFields );
                CPLFree( paiNumType );
                CPLFree( paiRank );
                CPLFree( pszFieldList );
                GDdetach( hGD );
            }

            CSLDestroy( papszGrids );
            GDclose( hHDF4 );
        }
        GDclose( hHDF4 );

        bIsHDF = ( nSubDatasets == 0 ); // Try to read as HDF
    }

    if( bIsHDF )
    {

/* -------------------------------------------------------------------- */
/*  Make a list of subdatasets from SDSs contained in input HDF file.	*/
/* -------------------------------------------------------------------- */
        int32   nDatasets;

        if ( SDfileinfo( poDS->hSD, &nDatasets, &nAttrs ) != 0 )
	    return NULL;

        for ( i = 0; i < nDatasets; i++ )
        {
            int32	iSDS;

            iSDS = SDselect( poDS->hSD, i );
            if ( SDgetinfo( iSDS, szName, &iRank, aiDimSizes, &iNumType, &nAttrs) != 0 )
                return NULL;
            
            if ( iRank == 1 )		// Skip 1D datsets
                    continue;

            // Do sort of known datasets. We will display only image bands
            if ( (poDS->iSubdatasetType == H4ST_SEAWIFS_L1A ) &&
                      !EQUALN( szName, "l1a_data", 8 ) )
                    continue;
            else
                pszName = szName;
            
            // Add datasets with multiple dimensions to the list of GDAL subdatasets
            nCount = CSLCount( poDS->papszSubDatasets ) / 2;
            sprintf( szTemp, "SUBDATASET_%d_NAME", nCount + 1 );
            // We will use SDS index as an identificator, because SDS names
            // are not unique. Filename also needed for further file opening
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets, szTemp, 
                  CPLSPrintf( "HDF4_SDS:%s:\"%s\":%ld", poDS->pszSubdatasetType,
                              poOpenInfo->pszFilename, (long)i) );
            sprintf( szTemp, "SUBDATASET_%d_DESC", nCount + 1 );
            pszString = SPrintArray( GDT_UInt32, aiDimSizes, iRank, "x" );
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets, szTemp,
                CPLSPrintf( "[%s] %s (%s)", pszString,
                            pszName, poDS->GetDataTypeName(iNumType)) );
            CPLFree( pszString );

            SDendaccess( iSDS );
        }

        SDend( poDS->hSD );
        poDS->hSD = 0;
    }

/* -------------------------------------------------------------------- */
/*      Build a list of raster images. Note, that HDF-EOS dataset may   */
/*      contain a raster image as well.                                 */
/* -------------------------------------------------------------------- */
    hHDF4 = Hopen(poOpenInfo->pszFilename, DFACC_READ, 0);
    poDS->hGR = GRstart( hHDF4 );

    if ( poDS->hGR != -1 )
    {
        if ( GRfileinfo( poDS->hGR, &poDS->nImages, &nAttrs ) == -1 )
            return NULL;
        
        for ( i = 0; i < poDS->nImages; i++ )
        {
            int32   iInterlaceMode; 
            int32   iGR = GRselect( poDS->hGR, i );

            // iRank in GR interface has another meaning. It represents number
            // of samples per pixel. aiDimSizes has only two dimensions.
            if ( GRgetiminfo( iGR, szName, &iRank, &iNumType, &iInterlaceMode,
                              aiDimSizes, &nAttrs ) != 0 )
                return NULL;
            nCount = CSLCount( poDS->papszSubDatasets ) / 2;
            sprintf( szTemp, "SUBDATASET_%d_NAME", nCount + 1 );
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets,
                szTemp,CPLSPrintf( "HDF4_GR:UNKNOWN:\"%s\":%ld",
                                   poOpenInfo->pszFilename, (long)i));
            sprintf( szTemp, "SUBDATASET_%d_DESC", nCount + 1 );
            pszString = SPrintArray( GDT_UInt32, aiDimSizes, 2, "x" );
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets,
                szTemp, CPLSPrintf( "[%sx%ld] %s (%s)", pszString, (long)iRank,
                                    szName, poDS->GetDataTypeName(iNumType)) );
            CPLFree( pszString );

            GRendaccess( iGR );
        }

        GRend( poDS->hGR );
        poDS->hGR = 0;
    }

    Hclose( hHDF4 );

    poDS->nRasterXSize = poDS->nRasterYSize = 512; // XXX: bogus values

    // Make sure we don't try to do any pam stuff with this dataset.
    poDS->nPamFlags |= GPF_NOSAVE;

/* -------------------------------------------------------------------- */
/*      If we have single subdataset only, open it immediately          */
/* -------------------------------------------------------------------- */
    if ( CSLCount( poDS->papszSubDatasets ) / 2 == 1 )
    {
        char *pszSDSName;
        pszSDSName = CPLStrdup( CSLFetchNameValue( poDS->papszSubDatasets,
                            "SUBDATASET_1_NAME" ));
        delete poDS;
        poDS = NULL;

        GDALDataset* poRetDS = (GDALDataset*) GDALOpen( pszSDSName, poOpenInfo->eAccess );
        CPLFree( pszSDSName );

        if (poRetDS)
        {
            poRetDS->SetDescription(poOpenInfo->pszFilename);
        }

        return poRetDS;
    }
    else
    {
/* -------------------------------------------------------------------- */
/*      Confirm the requested access is supported.                      */
/* -------------------------------------------------------------------- */
        if( poOpenInfo->eAccess == GA_Update )
        {
            delete poDS;
            CPLError( CE_Failure, CPLE_NotSupported, 
                      "The HDF4 driver does not support update access to existing"
                      " datasets.\n" );
            return NULL;
        }
    
    }

    return( poDS );
}
示例#2
0
GDALDataset *HDF4Dataset::Open( GDALOpenInfo * poOpenInfo )

{
    if( !Identify( poOpenInfo ) )
        return NULL;

    CPLMutexHolderD(&hHDF4Mutex);

/* -------------------------------------------------------------------- */
/*      Try opening the dataset.                                        */
/* -------------------------------------------------------------------- */

    // Attempt to increase maximum number of opened HDF files.
#ifdef HDF4_HAS_MAXOPENFILES
    intn nCurrMax = 0;
    intn nSysLimit = 0;

    if ( SDget_maxopenfiles(&nCurrMax, &nSysLimit) >= 0
         && nCurrMax < nSysLimit )
    {
        /*intn res = */SDreset_maxopenfiles( nSysLimit );
    }
#endif /* HDF4_HAS_MAXOPENFILES */

    int32 hHDF4 = Hopen(poOpenInfo->pszFilename, DFACC_READ, 0);

    if( hHDF4 <= 0 )
        return NULL;

    Hclose( hHDF4 );

/* -------------------------------------------------------------------- */
/*      Create a corresponding GDALDataset.                             */
/* -------------------------------------------------------------------- */
    // Release mutex otherwise we will deadlock with GDALDataset own mutex.
    CPLReleaseMutex(hHDF4Mutex);
    HDF4Dataset *poDS = new HDF4Dataset();
    CPLAcquireMutex(hHDF4Mutex, 1000.0);

    if( poOpenInfo->fpL != NULL )
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = NULL;
    }

/* -------------------------------------------------------------------- */
/*          Open HDF SDS Interface.                                     */
/* -------------------------------------------------------------------- */
    poDS->hSD = SDstart( poOpenInfo->pszFilename, DFACC_READ );

    if ( poDS->hSD == -1 )
    {
      // Release mutex otherwise we will deadlock with GDALDataset own mutex.
        CPLReleaseMutex(hHDF4Mutex);
        delete poDS;
        CPLAcquireMutex(hHDF4Mutex, 1000.0);
        CPLError( CE_Failure, CPLE_OpenFailed,
                  "Failed to open HDF4 file \"%s\" for SDS reading.",
                  poOpenInfo->pszFilename );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*              Now read Global Attributes.                             */
/* -------------------------------------------------------------------- */
    if ( poDS->ReadGlobalAttributes( poDS->hSD ) != CE_None )
    {
        // Release mutex otherwise we will deadlock with GDALDataset own mutex.
        CPLReleaseMutex(hHDF4Mutex);
        delete poDS;
        CPLAcquireMutex(hHDF4Mutex, 1000.0);
        CPLError( CE_Failure, CPLE_OpenFailed,
                  "Failed to read global attributes from HDF4 file \"%s\".",
                  poOpenInfo->pszFilename );
        return NULL;
    }

    poDS->SetMetadata( poDS->papszGlobalMetadata, "" );

/* -------------------------------------------------------------------- */
/*              Determine type of file we read.                         */
/* -------------------------------------------------------------------- */
    const char *pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                             "Signature");

    if ( pszValue != NULL && EQUAL( pszValue, pszGDALSignature ) )
    {
        poDS->iSubdatasetType = H4ST_GDAL;
        poDS->pszSubdatasetType = "GDAL_HDF4";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                            "Title")) != NULL
         && EQUAL( pszValue, "SeaWiFS Level-1A Data" ) )
    {
        poDS->iSubdatasetType = H4ST_SEAWIFS_L1A;
        poDS->pszSubdatasetType = "SEAWIFS_L1A";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                            "Title")) != NULL
        && EQUAL( pszValue, "SeaWiFS Level-2 Data" ) )
    {
        poDS->iSubdatasetType = H4ST_SEAWIFS_L2;
        poDS->pszSubdatasetType = "SEAWIFS_L2";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                            "Title")) != NULL
        && EQUAL( pszValue, "SeaWiFS Level-3 Standard Mapped Image" ) )
    {
        poDS->iSubdatasetType = H4ST_SEAWIFS_L3;
        poDS->pszSubdatasetType = "SEAWIFS_L3";
    }

    else if ( (pszValue = CSLFetchNameValue(poDS->papszGlobalMetadata,
                                            "L1 File Generated By")) != NULL
        && STARTS_WITH_CI(pszValue, "HYP version ") )
    {
        poDS->iSubdatasetType = H4ST_HYPERION_L1;
        poDS->pszSubdatasetType = "HYPERION_L1";
    }

    else
    {
        poDS->iSubdatasetType = H4ST_UNKNOWN;
        poDS->pszSubdatasetType = "UNKNOWN";
    }

/* -------------------------------------------------------------------- */
/*  If we have HDF-EOS dataset, process it here.                        */
/* -------------------------------------------------------------------- */
    int32 aiDimSizes[H4_MAX_VAR_DIMS] = {};  // TODO: Get this off of the stack.
    int32 iRank = 0;
    int32 iNumType = 0;
    int32 nAttrs = 0;
    bool bIsHDF = true;

    // Sometimes "HDFEOSVersion" attribute is not defined and we will
    // determine HDF-EOS datasets using other records
    // (see ReadGlobalAttributes() method).
    if ( poDS->bIsHDFEOS
         || CSLFetchNameValue(poDS->papszGlobalMetadata, "HDFEOSVersion") )
    {
/* -------------------------------------------------------------------- */
/*  Process swath layers.                                               */
/* -------------------------------------------------------------------- */
        hHDF4 = SWopen( poOpenInfo->pszFilename, DFACC_READ );
        if( hHDF4 < 0)
        {
            // Release mutex otherwise we will deadlock with GDALDataset own
            // mutex.
            CPLReleaseMutex(hHDF4Mutex);
            delete poDS;
            CPLAcquireMutex(hHDF4Mutex, 1000.0);
            CPLError( CE_Failure, CPLE_OpenFailed,
                      "Failed to open HDF-EOS file \"%s\" for swath reading.",
                      poOpenInfo->pszFilename );
            return NULL;
        }
        int32 nStrBufSize = 0;
        int32 nSubDatasets =
            SWinqswath(poOpenInfo->pszFilename, NULL, &nStrBufSize);

#ifdef DEBUG
        CPLDebug( "HDF4", "Number of HDF-EOS swaths: %d",
                  static_cast<int>( nSubDatasets ) );
#endif

        if ( nSubDatasets > 0 && nStrBufSize > 0 )
        {
            char *pszSwathList =
                static_cast<char *>( CPLMalloc( nStrBufSize + 1 ) );
            SWinqswath( poOpenInfo->pszFilename, pszSwathList, &nStrBufSize );
            pszSwathList[nStrBufSize] = '\0';

#ifdef DEBUG
            CPLDebug( "HDF4", "List of HDF-EOS swaths: %s", pszSwathList );
#endif

            char **papszSwaths =
                CSLTokenizeString2( pszSwathList, ",", CSLT_HONOURSTRINGS );
            CPLFree( pszSwathList );

            if ( nSubDatasets != CSLCount(papszSwaths) )
            {
                CSLDestroy( papszSwaths );
                // Release mutex otherwise we will deadlock with GDALDataset own
                // mutex.
                CPLReleaseMutex(hHDF4Mutex);
                delete poDS;
                CPLAcquireMutex(hHDF4Mutex, 1000.0);
                CPLDebug( "HDF4", "Cannot parse list of HDF-EOS grids." );
                return NULL;
            }

            for( int32 i = 0; i < nSubDatasets; i++)
            {
                const int32 hSW = SWattach( hHDF4, papszSwaths[i] );

                const int32 nFields
                    = SWnentries( hSW, HDFE_NENTDFLD, &nStrBufSize );
                char *pszFieldList = static_cast<char *>(
                    CPLMalloc( nStrBufSize + 1 ) );
                int32 *paiRank = static_cast<int32 *>(
                    CPLMalloc( nFields * sizeof(int32) ) );
                int32 *paiNumType = static_cast<int32 *>(
                    CPLMalloc( nFields * sizeof(int32) ) );

                SWinqdatafields( hSW, pszFieldList, paiRank, paiNumType );

#ifdef DEBUG
                {
                    char * const pszTmp =
                        SPrintArray( GDT_UInt32, paiRank, nFields, "," );

                    CPLDebug( "HDF4", "Number of data fields in swath %d: %d",
                              static_cast<int>( i ),
                              static_cast<int>( nFields ) );
                    CPLDebug( "HDF4", "List of data fields in swath %d: %s",
                              static_cast<int>( i ), pszFieldList );
                    CPLDebug( "HDF4", "Data fields ranks: %s", pszTmp );

                    CPLFree( pszTmp );
                }
#endif

                char **papszFields = CSLTokenizeString2( pszFieldList, ",",
                                                         CSLT_HONOURSTRINGS );

                char szTemp[256] = {'\0'};  // TODO: Get this off the stack.
                for( int32 j = 0; j < nFields; j++ )
                {
                    SWfieldinfo( hSW, papszFields[j], &iRank, aiDimSizes,
                                 &iNumType, NULL );

                    if ( iRank < 2 )
                        continue;

                    // Add field to the list of GDAL subdatasets.
                    const int nCount = CSLCount( poDS->papszSubDatasets ) / 2;
                    snprintf( szTemp, sizeof(szTemp),
                              "SUBDATASET_%d_NAME", nCount + 1 );
                    // We will use the field index as an identificator.
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                CPLSPrintf("HDF4_EOS:EOS_SWATH:\"%s\":%s:%s",
                                           poOpenInfo->pszFilename,
                                           papszSwaths[i], papszFields[j]) );

                    snprintf( szTemp, sizeof(szTemp),
                              "SUBDATASET_%d_DESC", nCount + 1 );
                    char *pszString = SPrintArray( GDT_UInt32, aiDimSizes,
                                                   iRank, "x" );
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                         CPLSPrintf( "[%s] %s %s (%s)",
                                                     pszString,
                                         papszFields[j],
                                         papszSwaths[i],
                                         poDS->GetDataTypeName(iNumType) ) );
                    CPLFree( pszString );
                    szTemp[0] = '\0';
                }

                CSLDestroy( papszFields );
                CPLFree( paiNumType );
                CPLFree( paiRank );
                CPLFree( pszFieldList );
                SWdetach( hSW );
            }

            CSLDestroy( papszSwaths );
        }
        SWclose( hHDF4 );

/* -------------------------------------------------------------------- */
/*  Process grid layers.                                                */
/* -------------------------------------------------------------------- */
        hHDF4 = GDopen( poOpenInfo->pszFilename, DFACC_READ );
        nSubDatasets = GDinqgrid( poOpenInfo->pszFilename, NULL, &nStrBufSize );

#ifdef DEBUG
        CPLDebug( "HDF4", "Number of HDF-EOS grids: %d",
                  static_cast<int>( nSubDatasets ) );
#endif

        if ( nSubDatasets > 0 && nStrBufSize > 0 )
        {
            char *pszGridList
                = static_cast<char *>( CPLMalloc( nStrBufSize + 1 ) );
            GDinqgrid( poOpenInfo->pszFilename, pszGridList, &nStrBufSize );

#ifdef DEBUG
            CPLDebug( "HDF4", "List of HDF-EOS grids: %s", pszGridList );
#endif

            char **papszGrids =
                CSLTokenizeString2( pszGridList, ",", CSLT_HONOURSTRINGS );
            CPLFree( pszGridList );

            if ( nSubDatasets != CSLCount(papszGrids) )
            {
                CSLDestroy( papszGrids );
                GDclose( hHDF4 );
                // Release mutex otherwise we will deadlock with GDALDataset own
                // mutex.
                CPLReleaseMutex(hHDF4Mutex);
                delete poDS;
                CPLAcquireMutex(hHDF4Mutex, 1000.0);
                CPLDebug( "HDF4", "Cannot parse list of HDF-EOS grids." );
                return NULL;
            }

            for( int32 i = 0; i < nSubDatasets; i++)
            {
                const int32 hGD = GDattach( hHDF4, papszGrids[i] );

                const int32 nFields
                    = GDnentries( hGD, HDFE_NENTDFLD, &nStrBufSize );
                char *pszFieldList = static_cast<char *>(
                    CPLMalloc( nStrBufSize + 1 ) );
                int32 *paiRank = static_cast<int32 *>(
                    CPLMalloc( nFields * sizeof(int32) ) );
                int32 *paiNumType = static_cast<int32 *>(
                    CPLMalloc( nFields * sizeof(int32) ) );

                GDinqfields( hGD, pszFieldList, paiRank, paiNumType );

#ifdef DEBUG
                {
                    char* pszTmp =
                            SPrintArray( GDT_UInt32, paiRank, nFields, "," );
                    CPLDebug( "HDF4", "Number of fields in grid %d: %d",
                              static_cast<int>( i ),
                              static_cast<int>( nFields ) );
                    CPLDebug( "HDF4", "List of fields in grid %d: %s",
                              static_cast<int>( i ), pszFieldList );
                    CPLDebug( "HDF4", "Fields ranks: %s", pszTmp );
                    CPLFree( pszTmp );
                }
#endif

                char **papszFields = CSLTokenizeString2( pszFieldList, ",",
                                                  CSLT_HONOURSTRINGS );

                char szTemp[256];
                for( int32 j = 0; j < nFields; j++ )
                {
                    GDfieldinfo( hGD, papszFields[j], &iRank, aiDimSizes,
                                 &iNumType, NULL );

                    if ( iRank < 2 )
                        continue;

                    // Add field to the list of GDAL subdatasets
                    const int nCount = CSLCount( poDS->papszSubDatasets ) / 2;
                    snprintf( szTemp, sizeof(szTemp),
                              "SUBDATASET_%d_NAME", nCount + 1 );
                    // We will use the field index as an identificator.
                    poDS->papszSubDatasets =
                        CSLSetNameValue(poDS->papszSubDatasets, szTemp,
                                CPLSPrintf( "HDF4_EOS:EOS_GRID:\"%s\":%s:%s",
                                            poOpenInfo->pszFilename,
                                            papszGrids[i], papszFields[j]));

                    snprintf( szTemp, sizeof(szTemp),
                              "SUBDATASET_%d_DESC", nCount + 1 );
                    char *pszString = SPrintArray( GDT_UInt32, aiDimSizes,
                                                   iRank, "x" );
                    poDS->papszSubDatasets =
                        CSLSetNameValue( poDS->papszSubDatasets, szTemp,
                                         CPLSPrintf("[%s] %s %s (%s)",
                                                    pszString,
                                             papszFields[j],
                                             papszGrids[i],
                                             poDS->GetDataTypeName(iNumType)) );
                    CPLFree( pszString );
                }

                CSLDestroy( papszFields );
                CPLFree( paiNumType );
                CPLFree( paiRank );
                CPLFree( pszFieldList );
                GDdetach( hGD );
            }

            CSLDestroy( papszGrids );
        }
        GDclose( hHDF4 );

        bIsHDF = ( nSubDatasets == 0 ); // Try to read as HDF
    }

    char szName[VSNAMELENMAX + 1];

    if( bIsHDF )
    {

/* -------------------------------------------------------------------- */
/*  Make a list of subdatasets from SDSs contained in input HDF file.   */
/* -------------------------------------------------------------------- */
        int32 nDatasets = 0;

        if ( SDfileinfo( poDS->hSD, &nDatasets, &nAttrs ) != 0 )
            return NULL;

        char szTemp[256] = {'\0'};  // TODO: Get this off the stack.
        const char *pszName = NULL;

        for( int32 i = 0; i < nDatasets; i++ )
        {
            const int32 iSDS = SDselect( poDS->hSD, i );
            if ( SDgetinfo( iSDS, szName, &iRank, aiDimSizes, &iNumType,
                            &nAttrs) != 0 )
                return NULL;

            if ( iRank == 1 )  // Skip 1D datsets
                    continue;

            // Do sort of known datasets. We will display only image bands
            if ( (poDS->iSubdatasetType == H4ST_SEAWIFS_L1A ) &&
                      !STARTS_WITH_CI(szName, "l1a_data") )
                    continue;
            else
                pszName = szName;

            // Add datasets with multiple dimensions to the list of GDAL
            // subdatasets.
            const int nCount = CSLCount( poDS->papszSubDatasets ) / 2;
            snprintf( szTemp, sizeof(szTemp),
                      "SUBDATASET_%d_NAME", nCount + 1 );
            // We will use SDS index as an identificator, because SDS names
            // are not unique. Filename also needed for further file opening
            poDS->papszSubDatasets = CSLSetNameValue(
                  poDS->papszSubDatasets,
                  szTemp,
                  CPLSPrintf( "HDF4_SDS:%s:\"%s\":%ld", poDS->pszSubdatasetType,
                              poOpenInfo->pszFilename,
                              static_cast<long>( i ) ) );
            snprintf( szTemp, sizeof(szTemp),
                      "SUBDATASET_%d_DESC", nCount + 1 );
            char *pszString = SPrintArray( GDT_UInt32, aiDimSizes, iRank, "x" );
            poDS->papszSubDatasets = CSLSetNameValue(
                poDS->papszSubDatasets,
                szTemp,
                CPLSPrintf( "[%s] %s (%s)", pszString,
                            pszName, poDS->GetDataTypeName(iNumType)) );
            CPLFree( pszString );

            SDendaccess( iSDS );
            szTemp[0] = '\0';
        }

        SDend( poDS->hSD );
        poDS->hSD = 0;
    }

/* -------------------------------------------------------------------- */
/*      Build a list of raster images. Note, that HDF-EOS dataset may   */
/*      contain a raster image as well.                                 */
/* -------------------------------------------------------------------- */

    hHDF4 = Hopen(poOpenInfo->pszFilename, DFACC_READ, 0);
    poDS->hGR = GRstart( hHDF4 );

    if ( poDS->hGR != -1 )
    {
        if ( GRfileinfo( poDS->hGR, &poDS->nImages, &nAttrs ) == -1 )
        {
            // Release mutex otherwise we will deadlock with GDALDataset own
            // mutex.
            CPLReleaseMutex(hHDF4Mutex);
            GRend( poDS->hGR );
            poDS->hGR = 0;
            Hclose( hHDF4 );
            delete poDS;
            CPLAcquireMutex(hHDF4Mutex, 1000.0);
            return NULL;
        }

        char szTemp[256] = {'\0'};  // TODO: Get this off the stack.
        for( int32 i = 0; i < poDS->nImages; i++ )
        {
            const int32 iGR = GRselect( poDS->hGR, i );

            // iRank in GR interface has another meaning. It represents number
            // of samples per pixel. aiDimSizes has only two dimensions.
            int32 iInterlaceMode = 0;
            if ( GRgetiminfo( iGR, szName, &iRank, &iNumType, &iInterlaceMode,
                              aiDimSizes, &nAttrs ) != 0 )
            {
                // Release mutex otherwise we will deadlock with GDALDataset
                // own mutex.
                CPLReleaseMutex(hHDF4Mutex);
                GRend( poDS->hGR );
                poDS->hGR = 0;
                Hclose( hHDF4 );
                delete poDS;
                CPLAcquireMutex(hHDF4Mutex, 1000.0);
                return NULL;
            }
            const int nCount = CSLCount( poDS->papszSubDatasets ) / 2;
            snprintf( szTemp, sizeof(szTemp),
                      "SUBDATASET_%d_NAME", nCount + 1 );
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets,
                szTemp,CPLSPrintf( "HDF4_GR:UNKNOWN:\"%s\":%ld",
                                   poOpenInfo->pszFilename,
                                   static_cast<long>( i ) ) );
            snprintf( szTemp, sizeof(szTemp),
                      "SUBDATASET_%d_DESC", nCount + 1 );
            char *pszString = SPrintArray( GDT_UInt32, aiDimSizes, 2, "x" );
            poDS->papszSubDatasets = CSLSetNameValue(poDS->papszSubDatasets,
                szTemp, CPLSPrintf( "[%sx%ld] %s (%s)", pszString,
                                    static_cast<long>( iRank ),
                                    szName, poDS->GetDataTypeName(iNumType)) );
            CPLFree( pszString );

            GRendaccess( iGR );
            szTemp[0] = '\0';
        }

        GRend( poDS->hGR );
        poDS->hGR = 0;
    }

    Hclose( hHDF4 );

    poDS->nRasterXSize = poDS->nRasterYSize = 512; // XXX: bogus values

    // Make sure we don't try to do any pam stuff with this dataset.
    poDS->nPamFlags |= GPF_NOSAVE;

/* -------------------------------------------------------------------- */
/*      If we have single subdataset only, open it immediately          */
/* -------------------------------------------------------------------- */
    if ( CSLCount( poDS->papszSubDatasets ) / 2 == 1 )
    {
        char *pszSDSName = CPLStrdup( CSLFetchNameValue( poDS->papszSubDatasets,
                                                         "SUBDATASET_1_NAME" ));
        // Release mutex otherwise we will deadlock with GDALDataset own mutex.
        CPLReleaseMutex(hHDF4Mutex);
        delete poDS;
        poDS = NULL;

        GDALDataset* poRetDS = reinterpret_cast<GDALDataset*>(
            GDALOpen( pszSDSName, poOpenInfo->eAccess ) );
        CPLFree( pszSDSName );

        CPLAcquireMutex(hHDF4Mutex, 1000.0);

        if (poRetDS)
        {
            poRetDS->SetDescription(poOpenInfo->pszFilename);
        }

        return poRetDS;
    }
    else
    {
/* -------------------------------------------------------------------- */
/*      Confirm the requested access is supported.                      */
/* -------------------------------------------------------------------- */
        if( poOpenInfo->eAccess == GA_Update )
        {
            // Release mutex otherwise we will deadlock with GDALDataset own
            // mutex.
            CPLReleaseMutex(hHDF4Mutex);
            delete poDS;
            CPLAcquireMutex(hHDF4Mutex, 1000.0);

            CPLError( CE_Failure, CPLE_NotSupported,
                      "The HDF4 driver does not support update access to "
                      "existing datasets." );
            return NULL;
        }

    }

    return poDS;
}