System.Xml.Xsl.XsltOld.RecordBuilder.AnalyzeProcessingInstruction C# (CSharp) Method

        private void AnalyzeProcessingInstruction() {
            Debug.Assert(this.mainNode.NodeType == XmlNodeType.ProcessingInstruction || this.mainNode.NodeType == XmlNodeType.XmlDeclaration);
            //Debug.Assert((object) this.currentInfo == (object) this.mainNode);

            StringBuilder newPI    = null;
            string        pi       = this.mainNode.Value;
            bool          question = false;
            int index = 0, begin = 0;

            for (; index < pi.Length; index ++) {
                switch (pi[index]) {
                case s_Question:
                    question = true;
                    break;
                case s_Greater:
                    if (question) {
                        if (newPI == null) {
                            newPI = new StringBuilder(pi, begin, index, 2 * pi.Length);
                        }
                        else {
                            newPI.Append(pi, begin, index - begin);
                        }
                        newPI.Append(s_SpaceGreater);
                        begin = index + 1;
                    }
                    question = false;
                    break;
                default:
                    question = false;
                    break;
                }
            }

            if (newPI != null) {
                if (begin < pi.Length) {
                    newPI.Append(pi, begin, pi.Length - begin);
                }
                this.mainNode.Value = newPI.ToString();
            }
        }