Flex formatting byte to MB, GB, TB, etc.

 labelFunction IS:

<mx:AdvancedDataGridColumn width="80" dataField="totalunpublished" headerText="Photo Usage" labelFunction="convertSize"/>

private var _levels:Array = [ 'bytes','Kb','MB','GB','TB','PB','EB','ZB','YB'];
private function convertSize(data:Object, column:AdvancedDataGridColumn):String {
     var bytes:Number=data[column.dataField];
    var index:uint = Math.floor(Math.log(bytes) / Math.log(1024));
    return (bytes / Math.pow(1024, index)).toFixed(2)+" "+this._levels[index];
}