Question

Imagine a scenario where, using xml, the user is able to specify ranges in a flexible manner, using any combination of ‘gte’, ‘gt’, ‘lte’, ‘lt’ or ‘eq’.

Here are some examples

<rangeElement gte='0' lt='5' ... /> <rangeElement gt='3' lte='7' ... /> <rangeElement eq='5' ... /> <rangeElement gt='10.5' ... /> 

Now what I need is two classes, Range and RangeCollection, that can deal with these.

The Range class might look something like this:

public class Range {    public LowerBoundInclusive { get; set; }    public LowerBoundExclusive { get; set; }    public UpperBoundInclusive { get; set; }    public UpperBoundExclusive { get; set; }    public object Data { get; set; }     public Range(XElement xmlElement)    {       ....    } } 

The RangeCollection class should have some basic way of sorting its ranges, detecting overlaps and returning a corresponding range given a value.

I’ve had a play with this but things quickly get fiendishly complex. Has anyone else seen a implementation of this, or want to give it a shot?

BTW. I know there are similar threads that tackle ranges but they do not adequately deal with the difference between ‘less-than-or-equal’ and ‘less-than’.

Answer 1

What you need is interval tree. It is not hard to find implementation in C# and modify it to make it suitable to your needs. I don’t see any problems with ‘<=’ or just ‘<‘ relations.