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);
}
}
}
//Class Constructor to Asssign the FileReader
public Scanner(FileReader fd)
{
this.fd = fd;
}