System.Xml.XPathNodePointer.XPathNodePointer C# (CSharp) Method

        static XPathNodePointer()
        {
#if DEBUG
            int max = 0, tempVal = 0;
            Array enumValues = Enum.GetValues(typeof(XmlNodeType));
            for (int i = 0; i < enumValues.Length; i++)
            {
                tempVal = (int)enumValues.GetValue(i);
                if (tempVal > max)
                    max = tempVal;
            }
            Debug.Assert(max == (int)XmlNodeType.XmlDeclaration);
#endif        
            s_xmlNodeType_To_XpathNodeType_Map = new int[20];
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.None)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Element)] = (int)XPathNodeType.Element;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Attribute)] = (int)XPathNodeType.Attribute;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Text)] = (int)XPathNodeType.Text;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.CDATA)] = (int)XPathNodeType.Text;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.EntityReference)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Entity)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.ProcessingInstruction)] = (int)XPathNodeType.ProcessingInstruction;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Comment)] = (int)XPathNodeType.Comment;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Document)] = (int)XPathNodeType.Root;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.DocumentType)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.DocumentFragment)] = (int)XPathNodeType.Root;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Notation)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.Whitespace)] = (int)XPathNodeType.Whitespace;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.SignificantWhitespace)] = (int)XPathNodeType.SignificantWhitespace;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.EndElement)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.EndEntity)] = -1;
            s_xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.XmlDeclaration)] = -1;
            // xmlNodeType_To_XpathNodeType_Map[(int)(XmlNodeType.All)] = -1;      
        }