System.Xml.Xsl.Runtime.ContentMergeIterator.DocOrderMerge C# (CSharp) Method

        private IteratorResult DocOrderMerge() {
            XmlNodeOrder cmp;
            Debug.Assert(this.state == IteratorState.HaveCurrentHaveNext);

            // Compare location of navCurrent with navNext
            cmp = this.navCurrent.ComparePosition(this.navNext);

            // If navCurrent is before navNext in document order,
            // If cmp = XmlNodeOrder.Unknown, then navCurrent is before navNext (since input is is doc order)
            if (cmp == XmlNodeOrder.Before || cmp == XmlNodeOrder.Unknown) {
                // Then navCurrent can be returned (it is guaranteed to be first in document order)
                return IteratorResult.HaveCurrentNode;
            }

            // If navCurrent is after navNext in document order, then delay returning navCurrent
            // Otherwise, discard navNext since it is positioned to the same node as navCurrent
            if (cmp == XmlNodeOrder.After) {
                this.navStack.Push(this.navCurrent);
                this.navCurrent = this.navNext;
                this.navNext = null;
            }

            // Need next input node
            this.state = IteratorState.HaveCurrentNeedNext;
            return IteratorResult.NeedInputNode;
        }
    }