ogrdatasource.cpp

mitab,读取MapInfo的地图文件

                                               pszNewName, papszOptions );
}

/************************************************************************/
/*                            DeleteLayer()                             */
/************************************************************************/

OGRErr OGRDataSource::DeleteLayer( int iLayer )

{
    (void) iLayer;
    CPLError( CE_Failure, CPLE_NotSupported,
              "DeleteLayer() not supported by this data source." );
              
    return OGRERR_UNSUPPORTED_OPERATION;
}

/************************************************************************/
/*                         OGR_DS_DeleteLayer()                         */
/************************************************************************/

OGRErr OGR_DS_DeleteLayer( OGRDataSourceH hDS, int iLayer )

{
    return ((OGRDataSource *) hDS)->DeleteLayer( iLayer );
}

/************************************************************************/
/*                           GetLayerByName()                           */
/************************************************************************/

OGRLayer *OGRDataSource::GetLayerByName( const char *pszName )

{
    if ( ! pszName )
        return NULL;

    int  i;

    /* first a case sensitive check */
    for( i = 0; i < GetLayerCount(); i++ )
    {
        OGRLayer *poLayer = GetLayer(i);

        if( strcmp( pszName, poLayer->GetLayerDefn()->GetName() ) == 0 )
            return poLayer;
    }

    /* then case insensitive */
    for( i = 0; i < GetLayerCount(); i++ )
    {
        OGRLayer *poLayer = GetLayer(i);

        if( EQUAL( pszName, poLayer->GetLayerDefn()->GetName() ) )
            return poLayer;
    }

    return NULL;
}

/************************************************************************/
/*                       OGR_DS_GetLayerByName()                        */
/************************************************************************/

OGRLayerH OGR_DS_GetLayerByName( OGRDataSourceH hDS, const char *pszName )

{
    return (OGRLayerH) ((OGRDataSource *) hDS)->GetLayerByName( pszName );
}

/************************************************************************/
/*                       ProcessSQLCreateIndex()                        */
/*                                                                      */
/*      The correct syntax for creating an index in our dialect of      */
/*      SQL is:                                                         */
/*                                                                      */
/*        CREATE INDEX ON <layername> USING <columnname>                */
/************************************************************************/

OGRErr OGRDataSource::ProcessSQLCreateIndex( const char *pszSQLCommand )

{
    char **papszTokens = CSLTokenizeString( pszSQLCommand );

/* -------------------------------------------------------------------- */
/*      Do some general syntax checking.                                */
/* -------------------------------------------------------------------- */
    if( CSLCount(papszTokens) != 6 
        || !EQUAL(papszTokens[0],"CREATE")
        || !EQUAL(papszTokens[1],"INDEX")
        || !EQUAL(papszTokens[2],"ON")
        || !EQUAL(papszTokens[4],"USING") )
    {
        CSLDestroy( papszTokens );
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Syntax error in CREATE INDEX command.\n"
                  "Was '%s'\n"
                  "Should be of form 'CREATE INDEX ON <table> USING <field>'",
                  pszSQLCommand );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Find the named layer.                                           */
/* -------------------------------------------------------------------- */
    int  i;
    OGRLayer *poLayer = NULL;

    for( i = 0; i < GetLayerCount(); i++ )
    {
        poLayer = GetLayer(i);
        
        if( EQUAL(poLayer->GetLayerDefn()->GetName(),papszTokens[3]) )
            break;
    }

    if( i >= GetLayerCount() )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "CREATE INDEX ON failed, no such layer as `%s'.",
                  papszTokens[3] );
        CSLDestroy( papszTokens );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Does this layer even support attribute indexes?                 */
/* -------------------------------------------------------------------- */
    if( poLayer->GetIndex() == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "CREATE INDEX ON not supported by this driver." );
        CSLDestroy( papszTokens );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Find the named field.                                           */
/* -------------------------------------------------------------------- */
    for( i = 0; i < poLayer->GetLayerDefn()->GetFieldCount(); i++ )
    {
        if( EQUAL(papszTokens[5],
                  poLayer->GetLayerDefn()->GetFieldDefn(i)->GetNameRef()) )
            break;
    }

    CSLDestroy( papszTokens );

    if( i >= poLayer->GetLayerDefn()->GetFieldCount() )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "`%s' failed, field not found.",
                  pszSQLCommand );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Attempt to create the index.                                    */
/* -------------------------------------------------------------------- */
    OGRErr eErr;

    eErr = poLayer->GetIndex()->CreateIndex( i );
    if( eErr == OGRERR_NONE )
        eErr = poLayer->GetIndex()->IndexAllFeatures( i );

    return eErr;
}

/************************************************************************/
/*                        ProcessSQLDropIndex()                         */
/*                                                                      */
/*      The correct syntax for droping one or more indexes in           */
/*      the OGR SQL dialect is:                                         */
/*                                                                      */
/*          DROP INDEX ON <layername> [USING <columnname>]              */
/************************************************************************/

OGRErr OGRDataSource::ProcessSQLDropIndex( const char *pszSQLCommand )

{
    char **papszTokens = CSLTokenizeString( pszSQLCommand );

/* -------------------------------------------------------------------- */
/*      Do some general syntax checking.                                */
/* -------------------------------------------------------------------- */
    if( (CSLCount(papszTokens) != 4 && CSLCount(papszTokens) != 6)
        || !EQUAL(papszTokens[0],"DROP")
        || !EQUAL(papszTokens[1],"INDEX")
        || !EQUAL(papszTokens[2],"ON") 
        || (CSLCount(papszTokens) == 6 && !EQUAL(papszTokens[4],"USING")) )
    {
        CSLDestroy( papszTokens );
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Syntax error in DROP INDEX command.\n"
                  "Was '%s'\n"
                  "Should be of form 'DROP INDEX ON <table> [USING <field>]'",
                  pszSQLCommand );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Find the named layer.                                           */
/* -------------------------------------------------------------------- */
    int  i;
    OGRLayer *poLayer=NULL;

    for( i = 0; i < GetLayerCount(); i++ )
    {
        poLayer = GetLayer(i);
        
        if( EQUAL(poLayer->GetLayerDefn()->GetName(),papszTokens[3]) )
            break;
    }

    if( i >= GetLayerCount() )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "CREATE INDEX ON failed, no such layer as `%s'.",
                  papszTokens[3] );
        CSLDestroy( papszTokens );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Does this layer even support attribute indexes?                 */
/* -------------------------------------------------------------------- */
    if( poLayer->GetIndex() == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Indexes not supported by this driver." );
        CSLDestroy( papszTokens );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      If we weren't given a field name, drop all indexes.             */
/* -------------------------------------------------------------------- */
    OGRErr eErr;

    if( CSLCount(papszTokens) == 4 )
    {
        for( i = 0; i < poLayer->GetLayerDefn()->GetFieldCount(); i++ )
        {
            OGRAttrIndex *poAttrIndex;

            poAttrIndex = poLayer->GetIndex()->GetFieldIndex(i);
            if( poAttrIndex != NULL )
            {
                eErr = poLayer->GetIndex()->DropIndex( i );
                if( eErr != OGRERR_NONE )
                    return eErr;
            }
        }

        CSLDestroy(papszTokens);
        return OGRERR_NONE;
    }

/* -------------------------------------------------------------------- */
/*      Find the named field.                                           */
/* -------------------------------------------------------------------- */
    for( i = 0; i < poLayer->GetLayerDefn()->GetFieldCount(); i++ )
    {
        if( EQUAL(papszTokens[5],
                  poLayer->GetLayerDefn()->GetFieldDefn(i)->GetNameRef()) )
            break;
    }

    CSLDestroy( papszTokens );

    if( i >= poLayer->GetLayerDefn()->GetFieldCount() )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "`%s' failed, field not found.",
                  pszSQLCommand );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Attempt to drop the index.                                      */
/* -------------------------------------------------------------------- */
    eErr = poLayer->GetIndex()->DropIndex( i );

    return eErr;
}

/************************************************************************/
/*                             ExecuteSQL()                             */
/************************************************************************/

OGRLayer * OGRDataSource::ExecuteSQL( const char *pszStatement,
                                      OGRGeometry *poSpatialFilter,
                                      const char *pszDialect )

{
    const char *pszError;
    swq_select *psSelectInfo = NULL;

    (void) pszDialect;

/* -------------------------------------------------------------------- */
/*      Handle CREATE INDEX statements specially.                       */
/* -------------------------------------------------------------------- */
    if( EQUALN(pszStatement,"CREATE INDEX",12) )
    {
        ProcessSQLCreateIndex( pszStatement );
        return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Handle DROP INDEX statements specially.                         */