BitsetsNET.RLEBitset.OrWith C# (CSharp) Method

        public void OrWith(IBitset otherSet)
        {
            RLEBitset otherRLESet = (RLEBitset)otherSet; // cast to an RLEBitset - errors if cannot cast

            Run current = new Run();
            int nextThisIndex, nextOtherIndex;

            if(this.length < otherRLESet.length)
            {
                this.length = otherRLESet.length;
            }

            if (this.runArray.Count == 0)
            {
                this.runArray = new List<Run>(otherRLESet.runArray);
                nextThisIndex = this.runArray.Count; //this stops the loops
                nextOtherIndex = this.runArray.Count;

            }
            else if (otherRLESet.runArray.Count == 0)
            {
                nextThisIndex = this.runArray.Count; //this stops the loops
                nextOtherIndex = this.runArray.Count;
            }
            else if (this.runArray[0].StartIndex <= otherRLESet.runArray[0].StartIndex)
            {
                current = this.runArray[0];
                nextThisIndex = 1;
                nextOtherIndex = 0;
            }
            else if (TryCreateUnion(this.runArray[0], otherRLESet.runArray[0], ref current))
            {
                //first two sets overlap
                this.runArray[0] = current;
                nextThisIndex = 1;
                nextOtherIndex = 1;
            }
            else
            {
                this.runArray.Insert(0, otherRLESet.runArray[0]);
                nextThisIndex = 1;
                nextOtherIndex = 1;
            }

            while ((nextThisIndex < this.runArray.Count) && (nextOtherIndex < otherRLESet.runArray.Count))
            {
                if (this.runArray[nextThisIndex].StartIndex >
                    otherRLESet.runArray[nextOtherIndex].StartIndex)
                {
                    MergeOtherRun(otherRLESet, ref current, ref nextThisIndex, ref nextOtherIndex);
                }
                else
                {
                    mergeExistingRun(ref current, ref nextThisIndex);
                }

            }

            if (nextThisIndex < this.runArray.Count)
            {
                //we finished the other, finish this one
                while (nextThisIndex < this.runArray.Count)
                {
                    mergeExistingRun(ref current, ref nextThisIndex);
                }
            }
            else
            {
                //we finished this one, finish the other
                while (nextOtherIndex < otherRLESet.runArray.Count)
                {
                    int lastNextIndex = this.runArray.Count;
                    MergeOtherRun(otherRLESet, ref current, ref lastNextIndex, ref nextOtherIndex);
                }
            }
        }