ogravce00layer.cpp

用于读取TAB、MIF、SHP文件的类

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

#if 0
int OGRAVCE00Layer::TestCapability( const char * pszCap )

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

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

int OGRAVCE00Layer::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++ )
        {
            OGRAVCE00Layer *poLayer = (OGRAVCE00Layer *) 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 OGRAVCE00Layer::CheckSetupTable(AVCE00Section *psTblSectionIn)
{
    if (psTableRead)
        return FALSE;

    const char *pszTableType = NULL;
    switch (eSectionType)
    {
    case AVCFileARC:
        pszTableType = ".AAT";
        break;

    case AVCFilePAL:
    case AVCFileLAB:
        pszTableType = ".PAT";
        break;

    default:
        break;
    }

/* -------------------------------------------------------------------- */
/*      Is the table type found anywhere in the section pszName?  Do    */
/*      a case insensitive check.                                       */
/* -------------------------------------------------------------------- */
    if( pszTableType == NULL )
        return FALSE;
    
    int iCheckOff;
    for( iCheckOff = 0; 
         psTblSectionIn->pszName[iCheckOff] != '\0'; 
         iCheckOff++ )
    {
        if( EQUALN(psTblSectionIn->pszName + iCheckOff, 
                   pszTableType, strlen(pszTableType) ) )
            break;
    }

    if( psTblSectionIn->pszName[iCheckOff] == '\0' )
        return FALSE;

    psTableSection = psTblSectionIn;

/* -------------------------------------------------------------------- */
/*      Try opening the table.                                          */
/* -------------------------------------------------------------------- */
    psTableRead = AVCE00ReadOpenE00(psTblSectionIn->pszFilename);
    if (psTableRead == NULL)
        return FALSE;

    /* advance to the specified line number */
    if (AVCE00ReadGotoSectionE00(psTableRead, psTableSection, 0) != 0)
    {
        AVCE00ReadCloseE00(psTableRead);
        psTableRead = NULL;
        return FALSE;
    }
    
    AVCE00ReadNextObjectE00(psTableRead);
    bNeedReset = 1;

    pszTableFilename = CPLStrdup(psTblSectionIn->pszFilename);
    nTableBaseField = poFeatureDefn->GetFieldCount();

	if (eSectionType == AVCFileLAB)
	{
        AVCE00ReadE00Ptr psInfo = ((OGRAVCE00DataSource *) poDS)->GetInfo();
        for( int iSection = 0; iSection < psInfo->numSections; iSection++ )
        {
            if( psInfo->pasSections[iSection].eType == AVCFilePAL )
                nTableAttrIndex = poFeatureDefn->GetFieldIndex( "PolyId" );
        }
	}

/* -------------------------------------------------------------------- */
/*      Setup attributes.                                               */
/* -------------------------------------------------------------------- */
    AppendTableDefinition( psTableRead->hParseInfo->hdr.psTableDef );

/* -------------------------------------------------------------------- */
/*      Close table so we don't have to many files open at once.        */
/* -------------------------------------------------------------------- */
    /* AVCE00ReadCloseE00( psTableRead ); */

    return TRUE;
}

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

int OGRAVCE00Layer::AppendTableFields( OGRFeature *poFeature )

{
    if (psTableRead == NULL)
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Open the table if it is currently closed.                       */
/* -------------------------------------------------------------------- */
    if (psTableRead == NULL)
    {
        psTableRead = AVCE00ReadOpenE00(pszTableFilename);
        if (psTableRead == NULL)
            return FALSE;

        /* advance to the specified line number */
    	if (AVCE00ReadGotoSectionE00(psTableRead, psTableSection, 0) != 0)
        {
            AVCE00ReadCloseE00(psTableRead);
            psTableRead = NULL;
            return FALSE;
        }
        nTablePos = 0;
    }

/* -------------------------------------------------------------------- */
/*      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 );

    if (nRecordId <= nTablePos)
    {
    	if (AVCE00ReadGotoSectionE00(psTableRead, psTableSection, 0) != 0)
			return FALSE;
        nTablePos = 0;
    }

    do
    {
        hRecord = AVCE00ReadNextObjectE00(psTableRead);
        ++nTablePos;
    }
    while (NULL != hRecord && nTablePos < nRecordId);

    if( hRecord == NULL )
        return FALSE;


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


int OGRAVCE00Layer::GetFeatureCount(int bForce)
{
    if (bForce && nFeatureCount < 0)
    {
        if (psSection->nFeatureCount < 0)
        {
            nFeatureCount = OGRLayer::GetFeatureCount(bForce);
        }
        else
        {
            nFeatureCount = psSection->nFeatureCount;
            if (psSection->eType == AVCFilePAL)
                --nFeatureCount;
        }
    }
    return nFeatureCount;
}