LexicalAnalysis.FSAChar.ReadChar C# (CSharp) Method

        public override void ReadChar(Char ch) {
            this._scanned = this._scanned + ch;
            switch (this._state) {
                case State.END:
                case State.ERROR:
                    this._state = State.ERROR;
                    break;
                case State.START:
                    if (IsChar(ch)) {
                        this._state = State.C;
                    } else if (ch == '\\') {
                        this._state = State.S;
                    } else {
                        this._state = State.ERROR;
                    }
                    break;
                case State.C:
                    this._state = State.END;
                    break;
                case State.S:
                    if (Utils.IsEscapeChar(ch)) {
                        this._state = State.C;
                    } else if (Utils.IsOctDigit(ch)) {
                        this._state = State.SO;
                    } else if (ch == 'x' || ch == 'X') {
                        this._state = State.SX;
                    } else {
                        this._state = State.ERROR;
                    }
                    break;
                case State.SX:
                    if (Utils.IsHexDigit(ch)) {
                        this._state = State.SXH;
                    } else {
                        this._state = State.ERROR;
                    }
                    break;
                case State.SXH:
                    if (Utils.IsHexDigit(ch)) {
                        this._state = State.SXHH;
                    } else {
                        this._state = State.END;
                    }
                    break;
                case State.SXHH:
                    this._state = State.END;
                    break;
                case State.SO:
                    if (Utils.IsOctDigit(ch)) {
                        this._state = State.SOO;
                    } else {
                        this._state = State.END;
                    }
                    break;
                case State.SOO:
                    if (Utils.IsOctDigit(ch)) {
                        this._state = State.SOOO;
                    } else {
                        this._state = State.END;
                    }
                    break;
                case State.SOOO:
                    this._state = State.END;
                    break;
                default:
                    this._state = State.ERROR;
                    break;
            }
        }