ogravcbinlayer.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

    if( poFeature != NULL && poFeature->GetFID() == 1 
        && psSection->eType == AVCFilePAL )
    {
        OGRFeature::DestroyFeature( poFeature );
        poFeature = GetFeature( -3 );
    }

    while( poFeature != NULL 
           && ((m_poAttrQuery != NULL
                && !m_poAttrQuery->Evaluate( poFeature ) )
               || !FilterGeometry( poFeature->GetGeometryRef() ) ) )
    {
        OGRFeature::DestroyFeature( poFeature );
        poFeature = GetFeature( -3 );
    }

    if( poFeature == NULL )
        ResetReading();

    return poFeature;
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRAVCBinLayer::TestCapability( const char * pszCap )

{
    if( eSectionType == AVCFileARC && EQUAL(pszCap,OLCRandomRead) )
        return TRUE;
    else 
        return OGRAVCLayer::TestCapability( pszCap );
}

/************************************************************************/
/*                        FormPolygonGeometry()                         */
/*                                                                      */
/*      Collect all the arcs forming edges to this polygon and form     */
/*      them into the appropriate OGR geometry on the target feature.   */
/************************************************************************/

int OGRAVCBinLayer::FormPolygonGeometry( OGRFeature *poFeature, 
                                         AVCPal *psPAL )

{
/* -------------------------------------------------------------------- */
/*      Try to find the corresponding ARC layer if not already          */
/*      recorded.                                                       */
/* -------------------------------------------------------------------- */
    if( poArcLayer == NULL )
    {
        int	i;

        for( i = 0; i < poDS->GetLayerCount(); i++ )
        {
            OGRAVCBinLayer *poLayer = (OGRAVCBinLayer *) poDS->GetLayer(i);

            if( poLayer->eSectionType == AVCFileARC )
                poArcLayer = poLayer;
        }

        if( poArcLayer == NULL )
            return FALSE;
    }

/* -------------------------------------------------------------------- */
/*	Read all the arcs related to this polygon, making a working	*/
/*	copy of them since the one returned by AVC is temporary.	*/
/* -------------------------------------------------------------------- */
    OGRGeometryCollection oArcs;
    int		iArc;

    for( iArc = 0; iArc < psPAL->numArcs; iArc++ )
    {
        OGRFeature *poArc;

        if( psPAL->pasArcs[iArc].nArcId == 0 )
            continue;

        // If the other side of the line is the same polygon then this
        // arc is a "bridge" arc and can be discarded.  If we don't discard
        // it, then we should double it as bridge arcs seem to only appear
        // once.  But by discarding it we ensure a multi-ring polygon will be
        // properly formed. 
        if( psPAL->pasArcs[iArc].nAdjPoly == psPAL->nPolyId )
            continue;

        poArc = poArcLayer->GetFeature( ABS(psPAL->pasArcs[iArc].nArcId) );

        if( poArc == NULL )
            return FALSE;

        if( poArc->GetGeometryRef() == NULL )
            return FALSE;

        oArcs.addGeometry( poArc->GetGeometryRef() );
        OGRFeature::DestroyFeature( poArc );
    }

    OGRErr  eErr;
    OGRPolygon *poPolygon;

    poPolygon = (OGRPolygon *) 
        OGRBuildPolygonFromEdges( (OGRGeometryH) &oArcs, TRUE, FALSE,  
                                  0.0, &eErr );
    if( poPolygon != NULL )
        poFeature->SetGeometryDirectly( poPolygon );

    return eErr == OGRERR_NONE;
}

/************************************************************************/
/*                          CheckSetupTable()                           */
/*                                                                      */
/*      Check if the named table exists, and if so, setup access to     */
/*      it (open it), and add it's fields to the feature class          */
/*      definition.                                                     */
/************************************************************************/

int OGRAVCBinLayer::CheckSetupTable()

{
    if( szTableName[0] == '\0' )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Scan for the indicated section.                                 */
/* -------------------------------------------------------------------- */
    AVCE00ReadPtr psInfo = ((OGRAVCBinDataSource *) poDS)->GetInfo();
    int           iSection;
    AVCE00Section *psSection = NULL;
    char	  szPaddedName[65];
    
    sprintf( szPaddedName, "%s%32s", szTableName, " " );
    szPaddedName[32] = '\0';

    for( iSection = 0; iSection < psInfo->numSections; iSection++ )
    {
        if( EQUAL(szPaddedName,psInfo->pasSections[iSection].pszName) 
            && psInfo->pasSections[iSection].eType == AVCFileTABLE )
            psSection = psInfo->pasSections + iSection;
    }

    if( psSection == NULL )
    {
        szTableName[0] = '\0';
        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      Try opening the table.                                          */
/* -------------------------------------------------------------------- */
    hTable = AVCBinReadOpen( psInfo->pszInfoPath,  szTableName,
                             psInfo->eCoverType, AVCFileTABLE,
                             psInfo->psDBCSInfo);
    
    if( hTable == NULL )
    {
        szTableName[0] = '\0';
        return FALSE;
    }
    
/* -------------------------------------------------------------------- */
/*      Setup attributes.                                               */
/* -------------------------------------------------------------------- */
    nTableBaseField = poFeatureDefn->GetFieldCount();
    
    AppendTableDefinition( hTable->hdr.psTableDef );

/* -------------------------------------------------------------------- */
/*      Close table so we don't have to many files open at once.        */
/* -------------------------------------------------------------------- */
    AVCBinReadClose( hTable );

    hTable = NULL;

    return TRUE;
}

/************************************************************************/
/*                         AppendTableFields()                          */
/************************************************************************/

int OGRAVCBinLayer::AppendTableFields( OGRFeature *poFeature )

{
    AVCE00ReadPtr psInfo = ((OGRAVCBinDataSource *) poDS)->GetInfo();

    if( szTableName[0] == '\0' )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Open the table if it is currently closed.                       */
/* -------------------------------------------------------------------- */
    if( hTable == NULL )
    {
        hTable = AVCBinReadOpen( psInfo->pszInfoPath,  szTableName,
                                 psInfo->eCoverType, AVCFileTABLE,
                                 psInfo->psDBCSInfo);
    }

    if( hTable == NULL )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Read the info record.                                           */
/*                                                                      */
/*      We usually assume the FID of the feature is the key but in a    */
/*      polygon coverage we need to use the PolyId attribute of LAB     */
/*      features to lookup the related attributes.  In this case        */
/*      nTableAttrIndex will already be setup to refer to the           */
/*      PolyId field.                                                   */
/* -------------------------------------------------------------------- */
    int	nRecordId;
    void *hRecord;

    if( nTableAttrIndex == -1 )
        nRecordId = poFeature->GetFID();
    else
        nRecordId = poFeature->GetFieldAsInteger( nTableAttrIndex );

    hRecord = AVCBinReadObject( hTable, nRecordId );
    if( hRecord == NULL )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Translate it.                                                   */
/* -------------------------------------------------------------------- */
    return TranslateTableFields( poFeature, nTableBaseField, 
                                 hTable->hdr.psTableDef, 
                                 (AVCField *) hRecord );
}