System.Text.RegularExpressions.RegexCharClass.SetDescription C# (CSharp) Method

        internal static String SetDescription(String set) {
            int mySetLength = set[SETLENGTH];
            int myCategoryLength = set[CATEGORYLENGTH];
            int myEndPosition = SETSTART + mySetLength + myCategoryLength;

            StringBuilder desc = new StringBuilder("[");

            int index = SETSTART;
            char ch1;
            char ch2;

            if (IsNegated(set)) 
                desc.Append('^');

            while (index < SETSTART + set[SETLENGTH]) {
                ch1 = set[index];
                if (index + 1 < set.Length)
                    ch2 = (char)(set[index + 1] - 1);
                else
                    ch2 = Lastchar;

                desc.Append(CharDescription(ch1));

                if (ch2 != ch1) {
                    if (ch1 + 1 != ch2)
                        desc.Append('-');
                    desc.Append(CharDescription(ch2));
                }
                index += 2;
            }

            while (index < SETSTART + set[SETLENGTH] + set[CATEGORYLENGTH]) {
                ch1 = set[index];
                if (ch1 == 0) {
                    bool found = false;
                    
                    int lastindex = set.IndexOf(GroupChar, index+1);
                    string group = set.Substring(index,lastindex-index + 1);

                    IDictionaryEnumerator en = _definedCategories.GetEnumerator();
                    while(en.MoveNext()) {
                        if (group.Equals(en.Value)) {
                            if ((short) set[index+1] > 0)
                                desc.Append("\\p{" + en.Key + "}");
                            else
                                desc.Append("\\P{" + en.Key + "}");

                            found = true;
                            break;
                        }
                    }

                    if (!found) {
                        if (group.Equals(Word))
                            desc.Append("\\w");
                        else if (group.Equals(NotWord))
                            desc.Append("\\W");
                        else 
                            Debug.Assert(false, "Couldn't find a goup to match '" + group + "'");
                    }
                    
                    index = lastindex;
                }
                else {
                    desc.Append(CategoryDescription(ch1));
                }
                    
                index++;
            }

            if (set.Length > myEndPosition) {
                desc.Append('-');
                desc.Append(SetDescription(set.Substring(myEndPosition)));
            }

            desc.Append(']');

            return desc.ToString();
        }

        internal void Dump()
        {
            int i;

            Debug.WriteLine("Direction:  " + (_rightToLeft ? "right-to-left" : "left-to-right"));
            Debug.WriteLine("Firstchars: " + (_fcPrefix == null ? "n/a" : RegexCharClass.SetDescription(_fcPrefix.Prefix)));
            Debug.WriteLine("Prefix:     " + (_bmPrefix == null ? "n/a" : Regex.Escape(_bmPrefix.ToString())));
            Debug.WriteLine("Anchors:    " + RegexFCD.AnchorDescription(_anchors));
            Debug.WriteLine("Scanchars:  " + (_scPrefix == null ? "n/a" : RegexCharClass.SetDescription(_scPrefix.Prefix)));
            Debug.WriteLine("");

            /*
             * if (_bmPrefix != null) {
             *  Debug.WriteLine("BoyerMoore:");
             *  Debug.WriteLine(_bmPrefix.Dump("    "));
             * }
             */
            for (i = 0; i < _codes.Length;)
            {
                Debug.WriteLine(OpcodeDescription(i));
                i += OpcodeSize(_codes[i]);
            }

            Debug.WriteLine("");
        }