animating UITableView updates

gistfile1.m

- (void)animateUpdateFromOldList:(NSArray *)oldList newList:(NSArray *)newList {
    NSMutableArray *workArray = [oldList mutableCopy];
    NSMutableSet *oldSet = [[NSMutableSet alloc] initWithArray:oldList];
    NSMutableSet *newSet = [[NSMutableSet alloc] initWithArray:newList];
    NSMutableSet *deleteSet = nil;
    NSMutableSet *insertSet = nil;
    static NSInteger offset = 0;
    
    deleteSet = [oldSet mutableCopy];
    [deleteSet minusSet:newSet];
    
    insertSet = [newSet mutableCopy];
    [insertSet minusSet:oldSet];

    NSLog(@"oldList.count: %d  newList.count: %d", [oldList count], [newList count]);
    [self.dynamicTableView beginUpdates];
    
    // Process deletes
    for (NSDictionary *deletedObject in deleteSet) {
        NSUInteger index = [oldList indexOfObject:deletedObject];
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:(NSInteger)index + offset inSection:0];
        [workArray removeObjectAtIndex:index];
        NSLog(@"DELETE row at %@", [NSArray arrayWithObject:indexPath]);
        [self.dynamicTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
    }
    
    // Process inserts
    for (NSDictionary *insertObject in insertSet) {
        NSUInteger index = [newList indexOfObject:insertObject];
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:(NSInteger)index + offset inSection:0];
        NSLog(@"INSERT row at %@", [NSArray arrayWithObject:indexPath]);
        [self.dynamicTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
    }
    
    // Process moves
    for (NSUInteger i = 0; i < [newList count]; i++) {
        NSDictionary *candidateObject = newList[i];
        
        if ([deleteSet containsObject:candidateObject] == NO &&
            [insertSet containsObject:candidateObject] == NO) {
            NSUInteger oldIndex = [oldList indexOfObject:candidateObject];
            NSUInteger newIndex = [newList indexOfObject:candidateObject];
            NSIndexPath *oldIndexPath = [NSIndexPath indexPathForRow:(NSInteger)oldIndex + offset inSection:0];
            NSIndexPath *newIndexPath = [NSIndexPath indexPathForRow:(NSInteger)newIndex + offset inSection:0];
            
            if (oldIndex != newIndex) {
                NSLog(@"MOVE row at %@ to %@", oldIndexPath, newIndexPath);
                [self.dynamicTableView moveRowAtIndexPath:oldIndexPath toIndexPath:newIndexPath];
            }
        }
    }
    [self.dynamicTableView endUpdates];
}