Exemple #1
0
        public void getToken(FileReader fd)
        {  /* index for storing into tokenString */
            int tokenStringIndex = 0;

            char[] tokenString = new char[40];
            //Holds current token
            TokenType currentToken = TokenType.ERROR;
            /* current state - always begins at START */
            StateType state = StateType.START;
            /* flag to indicate save to tokenString */
            Boolean save;

            while (state != StateType.DONE)
            {
                if (!(fd.lineno < fd.lines))
                {
                    currentToken = TokenType.T_ENDL;
                    break;
                }
                char c = fd.getNextChar();
                save = true;
                switch (state)
                {
                case StateType.START:
                    if (char.IsDigit(c))
                    {
                        state = StateType.INNUM;
                    }
                    else if (char.IsLetter(c))
                    {
                        state = StateType.INID;
                    }
                    else if (c == ':')
                    {
                        state = StateType.INASSIGN;
                    }
                    else if ((c == ' ') || (c == '\t') || (c == '\n'))
                    {
                        save = false;
                    }
                    else if (c == '"')
                    {
                        StringQuotesCount++;
                        state = StateType.STRING;
                    }
                    else if (c == '/')
                    {
                        state = StateType.COMMENTDIV;
                    }
                    else if (c == '&')
                    {
                        state = StateType.ANDLOGIC;
                    }
                    else if (c == '|')
                    {
                        state = StateType.ORLOGIC;
                    }
                    else
                    {
                        state = StateType.DONE;
                        switch (c)
                        {
                        case '=':
                            currentToken = TokenType.T_EQUALS;
                            break;

                        case '<':
                            currentToken = TokenType.T_LESSTHAN;
                            break;

                        case '>':
                            currentToken = TokenType.T_LARGERTHAN;
                            break;

                        case '+':
                            currentToken = TokenType.T_PLUS;
                            break;

                        case '-':
                            currentToken = TokenType.T_MINUS;
                            break;

                        case '*':
                            currentToken = TokenType.T_TIMES;
                            break;

                        case '(':
                            LeftParanthesisCount++;
                            currentToken = TokenType.T_LEFTPAREN;
                            break;

                        case ')':
                            RightParanthesisCount++;
                            currentToken = TokenType.T_RIGHTPAREN;
                            break;

                        case ',':
                            currentToken = TokenType.T_COMMA;
                            break;

                        case '{':
                            LeftBracesCount++;
                            currentToken = TokenType.T_LBRACES;
                            break;

                        case '}':
                            RightBracesCount++;
                            currentToken = TokenType.T_RBRACES;
                            break;

                        case ';':
                            currentToken = TokenType.T_SEMICOLON;
                            break;

                        default:
                            currentToken = TokenType.IllegalChar;
                            break;
                        }
                    }
                    break;

                case StateType.INCOMMENT:
                    save = false;
                    if (c == '*')
                    {
                        state = StateType.ENDCOMMENT;
                    }
                    break;

                case StateType.COMMENTDIV:
                    if (c == '*')
                    {
                        save  = false;
                        state = StateType.INCOMMENT;
                        tokenStringIndex--;
                    }
                    else
                    {
                        currentToken = TokenType.T_OVER;
                        save         = false;
                        fd.linepos--;
                        state = StateType.DONE;
                    }
                    break;

                case StateType.ENDCOMMENT:
                    if (c == '/')
                    {
                        save  = false;
                        state = StateType.START;
                    }
                    else
                    {
                        state = StateType.INCOMMENT;
                    }
                    break;

                case StateType.ANDLOGIC:
                    state = StateType.DONE;
                    if (c == '&')
                    {
                        currentToken = TokenType.AND;
                    }
                    else
                    {
                        fd.linepos--;
                        save         = false;
                        currentToken = TokenType.ERROR;
                    }
                    break;

                case StateType.ORLOGIC:
                    state = StateType.DONE;
                    if (c == '|')
                    {
                        currentToken = TokenType.OR;
                    }
                    else
                    {
                        fd.linepos--;
                        save         = false;
                        currentToken = TokenType.ERROR;
                    }
                    break;

                case StateType.STRING:
                    if (c == '"')
                    {
                        StringQuotesCount++;
                        state        = StateType.DONE;
                        currentToken = TokenType.T_STRING;
                    }
                    break;

                case StateType.INASSIGN:
                    state = StateType.DONE;
                    if (c == '=')
                    {
                        currentToken = TokenType.T_ASSIGN;
                    }
                    else
                    {     /* backup in the input */
                        fd.linepos--;
                        save         = false;
                        currentToken = TokenType.ERROR;
                    }
                    break;

                case StateType.INNUM:
                    if (c == '.')
                    {
                        state = StateType.INDECIMAL;
                    }
                    else if (char.IsLetter(c))
                    {
                        currentToken = TokenType.ERROR;
                        state        = StateType.DONE;
                    }
                    else if (!char.IsDigit(c))
                    {     /* backup in the input */
                        fd.linepos--;
                        save         = false;
                        state        = StateType.DONE;
                        currentToken = TokenType.NUMBER;
                    }
                    break;

                case StateType.INDECIMAL:
                    if (!char.IsDigit(c))
                    {     /* backup in the input */
                        fd.linepos--;
                        save         = false;
                        state        = StateType.DONE;
                        currentToken = TokenType.NUMBER;
                    }
                    break;

                case StateType.INID:
                    if (char.IsDigit(c))
                    {
                        state = StateType.ID;
                    }
                    else if (!char.IsLetter(c))
                    {     /* backup in the input */
                        fd.linepos--;
                        save         = false;
                        state        = StateType.DONE;
                        currentToken = ReservedWordsLookup(new string(tokenString).Trim('\0'));
                    }
                    break;

                case StateType.ID:
                    if (!(char.IsLetter(c) || char.IsDigit(c)))
                    {     /* backup in the input */
                        fd.linepos--;
                        save         = false;
                        currentToken = TokenType.ID;
                        state        = StateType.DONE;
                    }
                    break;

                case StateType.DONE:
                default:     /* should never happen */
                    Console.Write("Scanner Bug: state= %d\n", state);
                    state        = StateType.DONE;
                    currentToken = TokenType.ERROR;
                    break;
                }
                if (save)
                {
                    if (!(tokenStringIndex > 39))
                    {
                        tokenString[tokenStringIndex++] = c;
                    }
                }
                if (state == StateType.DONE)
                {
                    if (tokenStringIndex > 39)
                    {
                        currentToken = TokenType.TokenLengthExceeded;
                    }
                    addScanned(tokenString, currentToken);
                }
            }
        }
Exemple #2
0
 //Class Constructor to Asssign the FileReader
 public Scanner(FileReader fd)
 {
     this.fd = fd;
 }