ogrogdilayer.cpp

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

    }

/* -------------------------------------------------------------------- */
/*      Set attributes                                                  */
/* -------------------------------------------------------------------- */
    char *pszAttrList = ECSOBJECTATTR(psResult);

    for( int iField = 0; iField < m_poFeatureDefn->GetFieldCount(); iField++ )
    {
        char        *pszFieldStart;
        int         nNameLen;
        char        chSavedChar;

        /* parse out the next attribute value */
        if( !ecs_FindElement( pszAttrList, &pszFieldStart, &pszAttrList,
                              &nNameLen, NULL ) )
        {
            nNameLen = 0;
            pszFieldStart = pszAttrList;
        }

        /* Skip any trailing white space (for string constants). */

        if( nNameLen > 0 && pszFieldStart[nNameLen-1] == ' ' )
            nNameLen--;

        /* skip leading white space */
        while( pszFieldStart[0] == ' ' && nNameLen > 0 )
        {
            pszFieldStart++;
            nNameLen--;
        }

        /* zero terminate the single field value, but save the          */
        /* character we overwrote, so we can restore it when done.      */

        chSavedChar = pszFieldStart[nNameLen];
        pszFieldStart[nNameLen] = '\0';

        /* OGR takes care of all field type conversions for us! */

        poFeature->SetField(iField, pszFieldStart);

        pszFieldStart[nNameLen] = chSavedChar;
    }

/* -------------------------------------------------------------------- */
/*      Apply the text associated with text features if appropriate.    */
/* -------------------------------------------------------------------- */
    if( m_eFamily == Text )
    {
        poFeature->SetField( "text", ECSGEOM(psResult).text.desc );
    }

/* -------------------------------------------------------------------- */
/*      Do we need to apply an attribute test?                          */
/* -------------------------------------------------------------------- */
    if( (m_poAttrQuery != NULL
         && !m_poAttrQuery->Evaluate( poFeature ) ) 
        || (m_poFilterGeom != NULL 
            && !FilterGeometry( poFeature->GetGeometryRef() ) ) )
    {
        delete poFeature;
        goto TryAgain;
    }

    return poFeature;
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGROGDILayer::GetFeature( long nFeatureId )

{
    ecs_Result  *psResult;

    if (m_nTotalShapeCount != -1 && nFeatureId > m_nTotalShapeCount)
        return NULL;

    if (m_iNextShapeId > nFeatureId )
        ResetReading();

    while(m_iNextShapeId != nFeatureId)
    {
        psResult = cln_GetNextObject(m_nClientID);
        if (ECSSUCCESS(psResult))
            m_iNextShapeId++;
        else
        {
            // We probably reached EOF... keep track of shape count.
            m_nTotalShapeCount = m_iNextShapeId;
            return NULL;
        }
    }

    // OK, we're ready to read the requested feature...
    return GetNextFeature();
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/*                                                                      */
/*      If a spatial filter is in effect, we turn control over to       */
/*      the generic counter.  Otherwise we return the total count.      */
/*      Eventually we should consider implementing a more efficient     */
/*      way of counting features matching a spatial query.              */
/************************************************************************/

int OGROGDILayer::GetFeatureCount( int bForce )

{
    if( m_nTotalShapeCount == -1)
    {
        m_nTotalShapeCount = OGRLayer::GetFeatureCount( bForce );
    }

    return m_nTotalShapeCount;
}

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

int OGROGDILayer::TestCapability( const char * pszCap )

{
/* -------------------------------------------------------------------- */
/*      Hummm... what are the proper capabilities...                    */
/*      Does OGDI have any idea of capabilities???                      */
/*      For now just return FALSE for everything.                       */
/* -------------------------------------------------------------------- */
#ifdef __TODO__
    if( EQUAL(pszCap,OLCRandomRead) )
        return TRUE;

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
        return m_poFilterGeom == NULL;

    else if( EQUAL(pszCap,OLCFastSpatialFilter) )
        return FALSE;

    else 
        return FALSE;
#endif

    return FALSE;
}



/************************************************************************/
/*                          BuildFeatureDefn()                          */
/*                                                                      */
/*      (private) Initializes the schema in m_poFeatureDefn             */
/************************************************************************/

void OGROGDILayer::BuildFeatureDefn()
{
    ecs_Result  *psResult;
    ecs_ObjAttributeFormat *oaf;
    int         i, numFields;
    const char  *pszGeomName;
    OGRwkbGeometryType eLayerGeomType;

/* -------------------------------------------------------------------- */
/*      Feature Defn name will be "<OGDILyrName>_<FeatureFamily>"       */
/* -------------------------------------------------------------------- */
    
    switch(m_eFamily)
    {
      case Point:
        pszGeomName = "point";
        eLayerGeomType = wkbPoint;
        break;
      case Line:
        pszGeomName = "line";
        eLayerGeomType = wkbLineString;
        break;
      case Area:
        pszGeomName = "area";
        eLayerGeomType = wkbPolygon;
        break;
      case Text:
        pszGeomName = "text";
        eLayerGeomType = wkbPoint;
        break;
      default:
        pszGeomName = "unknown";
        eLayerGeomType = wkbUnknown;
        break;
    }

    m_poFeatureDefn = new OGRFeatureDefn(CPLSPrintf("%s_%s", 
                                                    m_pszOGDILayerName, 
                                                    pszGeomName ));
    m_poFeatureDefn->SetGeomType(eLayerGeomType);

/* -------------------------------------------------------------------- */
/*      Fetch schema from OGDI server and map to OGR types              */
/* -------------------------------------------------------------------- */
    psResult = cln_GetAttributesFormat( m_nClientID );
    if( ECSERROR( psResult ) )
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "ECSERROR: %s\n", psResult->message);
        return;
    }

    oaf = &(ECSRESULT(psResult).oaf);
    numFields = oaf->oa.oa_len;
    for( i = 0; i < numFields; i++ )
    {
        OGRFieldDefn    oField("", OFTInteger);

        oField.SetName( oaf->oa.oa_val[i].name );
        oField.SetPrecision( 0 );

        switch( oaf->oa.oa_val[i].type )
        {
          case Decimal:
          case Smallint:
          case Integer:
            oField.SetType( OFTInteger );
            if( oaf->oa.oa_val[i].lenght > 0 )
                oField.SetWidth( oaf->oa.oa_val[i].lenght );
            else
                oField.SetWidth( 11 );
            break;

          case Numeric:
          case Real:
          case Float:
          case Double:
            oField.SetType( OFTReal );
            if( oaf->oa.oa_val[i].lenght > 0 )
            {
                oField.SetWidth( oaf->oa.oa_val[i].lenght );
                oField.SetPrecision( oaf->oa.oa_val[i].precision );
            }
            else
            {
                oField.SetWidth( 18 );
                oField.SetPrecision( 7 );
            }
            break;

          case Char:
          case Varchar:
          case Longvarchar:
          default:
            oField.SetType( OFTString );
            if( oaf->oa.oa_val[i].lenght > 0 )
                oField.SetWidth( oaf->oa.oa_val[i].lenght );
            else
                oField.SetWidth( 64 );
            break;

        }

        m_poFeatureDefn->AddFieldDefn( &oField );
    }

/* -------------------------------------------------------------------- */
/*      Add a text attribute for text objects.                          */
/* -------------------------------------------------------------------- */
    if( m_eFamily == Text )
    {
        OGRFieldDefn    oField("text", OFTString);

        m_poFeatureDefn->AddFieldDefn( &oField );
    }
    
}