             index = (item%columnCount)
         case .CHTCollectionViewWaterfallLayoutItemRenderDirectionRightToLeft:
             index = (columnCount - 1) - (item % columnCount);
-        default:
-            index = self.shortestColumnIndexInSection(section)
         }
         return index
     }

            }
        }
        for var i = begin; i < end; i++ {
            var attr = self.allItemAttributes.objectAtIndex(i) as! UICollectionViewLayoutAttributes
            if CGRectIntersectsRect(rect, attr.frame) {
                attrs.addObject(attr)
            }
        }
            
        return NSArray(array: attrs) as! [UICollectionViewLayoutAttributes]
    }
    
    override func shouldInvalidateLayoutForBoundsChange (newBounds : CGRect) -> Bool {
        var oldBounds = self.collectionView!.bounds
        if CGRectGetWidth(newBounds) != CGRectGetWidth(oldBounds){
            return true
        }

        
        for var section = 0; section < numberOfSections; ++section{
            let columnCount = self.columnCountForSection(section)
            let sectionColumnHeights = NSMutableArray(capacity: columnCount)
            for var idx = 0; idx < columnCount; idx++ {
                sectionColumnHeights.addObject(idx)
            }
