public static JSONNode Parse()

in Azure Cloud Tutorials/Assets/MRTK.Tutorials.AzureCloudServices/Scripts/BotDirectLine/SimpleJSON.cs [231:385]
144 lines of code
42 McCabe index (conditional complexity)

        public static JSONNode Parse(string aJSON)
        {
            Stack<JSONNode> stack = new Stack<JSONNode>();
            JSONNode ctx = null;
            int i = 0;
            string Token = "";
            string TokenName = "";
            bool QuoteMode = false;
            while (i < aJSON.Length)
            {
                switch (aJSON[i])
                {
                    case '{':
                        if (QuoteMode)
                        {
                            Token += aJSON[i];
                            break;
                        }
                        stack.Push(new JSONClass());
                        if (ctx != null)
                        {
                            TokenName = TokenName.Trim();
                            if (ctx is JSONArray)
                                ctx.Add(stack.Peek());
                            else if (TokenName != "")
                                ctx.Add(TokenName,stack.Peek());
                        }
                        TokenName = "";
                        Token = "";
                        ctx = stack.Peek();
                    break;
 
                    case '[':
                        if (QuoteMode)
                        {
                            Token += aJSON[i];
                            break;
                        }
 
                        stack.Push(new JSONArray());
                        if (ctx != null)
                        {
                            TokenName = TokenName.Trim();
                            if (ctx is JSONArray)
                                ctx.Add(stack.Peek());
                            else if (TokenName != "")
                                ctx.Add(TokenName,stack.Peek());
                        }
                        TokenName = "";
                        Token = "";
                        ctx = stack.Peek();
                    break;
 
                    case '}':
                    case ']':
                        if (QuoteMode)
                        {
                            Token += aJSON[i];
                            break;
                        }
                        if (stack.Count == 0)
                            throw new Exception("JSON Parse: Too many closing brackets");
 
                        stack.Pop();
                        if (Token != "")
                        {
                            TokenName = TokenName.Trim();
                            if (ctx is JSONArray)
                                ctx.Add(Token);
                            else if (TokenName != "")
                                ctx.Add(TokenName,Token);
                        }
                        TokenName = "";
                        Token = "";
                        if (stack.Count>0)
                            ctx = stack.Peek();
                    break;
 
                    case ':':
                        if (QuoteMode)
                        {
                            Token += aJSON[i];
                            break;
                        }
                        TokenName = Token;
                        Token = "";
                    break;
 
                    case '"':
                        QuoteMode ^= true;
                    break;
 
                    case ',':
                        if (QuoteMode)
                        {
                            Token += aJSON[i];
                            break;
                        }
                        if (Token != "")
                        {
                            if (ctx is JSONArray)
                                ctx.Add(Token);
                            else if (TokenName != "")
                                ctx.Add(TokenName, Token);
                        }
                        TokenName = "";
                        Token = "";
                    break;
 
                    case '\r':
                    case '\n':
                    break;
 
                    case ' ':
                    case '\t':
                        if (QuoteMode)
                            Token += aJSON[i];
                    break;
 
                    case '\\':
                        ++i;
                        if (QuoteMode)
                        {
                            char C = aJSON[i];
                            switch (C)
                            {
                                case 't' : Token += '\t'; break;
                                case 'r' : Token += '\r'; break;
                                case 'n' : Token += '\n'; break;
                                case 'b' : Token += '\b'; break;
                                case 'f' : Token += '\f'; break;
                                case 'u':
                                {
                                    string s = aJSON.Substring(i+1,4);
                                    Token += (char)int.Parse(s, System.Globalization.NumberStyles.AllowHexSpecifier);
                                    i += 4;
                                    break;
                                }
                                default  : Token += C; break;
                            }
                        }
                    break;
 
                    default:
                        Token += aJSON[i];
                    break;
                }
                ++i;
            }
            if (QuoteMode)
            {
                throw new Exception("JSON Parse: Quotation marks seems to be messed up.");
            }
            return ctx;
        }