System.Xml.XmlConvert.DecodeName C# (CSharp) Méthode

        public static string DecodeName(string name)
        {
            if (name == null || name.Length == 0)
                return name;

            StringBuilder bufBld = null;

            int length = name.Length;
            int copyPosition = 0;

            int underscorePos = name.IndexOf('_');
            MatchCollection mc = null;
            IEnumerator en = null;
            if (underscorePos >= 0)
            {
                if (s_decodeCharPattern == null)
                {
                    s_decodeCharPattern = new Regex("_[Xx]([0-9a-fA-F]{4}|[0-9a-fA-F]{8})_");
                }
                mc = s_decodeCharPattern.Matches(name, underscorePos);
                en = mc.GetEnumerator();
            }
            else
            {
                return name;
            }
            int matchPos = -1;
            if (en != null && en.MoveNext())
            {
                Match m = (Match)en.Current;
                matchPos = m.Index;
            }

            for (int position = 0; position < length - s_encodedCharLength + 1; position++)
            {
                if (position == matchPos)
                {
                    if (en.MoveNext())
                    {
                        Match m = (Match)en.Current;
                        matchPos = m.Index;
                    }

                    if (bufBld == null)
                    {
                        bufBld = new StringBuilder(length + 20);
                    }
                    bufBld.Append(name, copyPosition, position - copyPosition);

                    if (name[position + 6] != '_')
                    { //_x1234_
                        Int32 u =
                            FromHex(name[position + 2]) * 0x10000000 +
                            FromHex(name[position + 3]) * 0x1000000 +
                            FromHex(name[position + 4]) * 0x100000 +
                            FromHex(name[position + 5]) * 0x10000 +

                            FromHex(name[position + 6]) * 0x1000 +
                            FromHex(name[position + 7]) * 0x100 +
                            FromHex(name[position + 8]) * 0x10 +
                            FromHex(name[position + 9]);

                        if (u >= 0x00010000)
                        {
                            if (u <= 0x0010ffff)
                            { //convert to two chars
                                copyPosition = position + s_encodedCharLength + 4;
                                char lowChar, highChar;
                                XmlCharType.SplitSurrogateChar(u, out lowChar, out highChar);
                                bufBld.Append(highChar);
                                bufBld.Append(lowChar);
                            }
                            //else bad ucs-4 char don't convert
                        }
                        else
                        { //convert to single char
                            copyPosition = position + s_encodedCharLength + 4;
                            bufBld.Append((char)u);
                        }
                        position += s_encodedCharLength - 1 + 4; //just skip
                    }
                    else
                    {
                        copyPosition = position + s_encodedCharLength;
                        bufBld.Append((char)(
                            FromHex(name[position + 2]) * 0x1000 +
                            FromHex(name[position + 3]) * 0x100 +
                            FromHex(name[position + 4]) * 0x10 +
                            FromHex(name[position + 5])));
                        position += s_encodedCharLength - 1;
                    }
                }
            }
            if (copyPosition == 0)
            {
                return name;
            }
            else
            {
                if (copyPosition < length)
                {
                    bufBld.Append(name, copyPosition, length - copyPosition);
                }
                return bufBld.ToString();
            }
        }