public override void Get(IInputBuffer buffer)
{
char ch; // current character
StringBuilder tokenBuilder = new StringBuilder();
tokenBuilder.Append('\''); // opening quote
//--Get the string.
ch = buffer.GetChar(); // first char after opening quote
while (ch != 0x7f)
{
if (ch == '\'')
{ // look for another quote
//--Fetched a quote. Now check for an adjacent quote,
//--since two consecutive quotes represent a single
//--quote in the string.
ch = buffer.GetChar();
if (ch != '\'') break; // not another quote, so previous
// quote ended the string
}
//--Replace the end of line character with a blank.
else if (ch == '\0') ch = ' ';
//--Append current char to string, then get the next char.
tokenBuilder.Append(ch);
ch = buffer.GetChar();
}
tokenBuilder.Append('\''); // closing quote
tokenString = tokenBuilder.ToString();
code = TTokenCode.String;
}
public override void Get(IInputBuffer buffer)
{
StringBuilder tokenBuilder = new StringBuilder();
tokenBuilder.Append(buffer.CurrentChar);
tokenString = tokenBuilder.ToString();
buffer.GetChar();
code = TTokenCode.Error;
}
public override void Get(IInputBuffer buffer)
{
StringBuilder tokenBuilder = new StringBuilder();
char ch = buffer.CurrentChar; // char fetched from input
do
{
tokenBuilder.Append(ch);
ch = buffer.GetChar();
} while (characterMap[ch] == CharCode.Letter ||
characterMap[ch] == CharCode.Digit);
tokenString = tokenBuilder.ToString();
checkForReservedWord();
}
public override void Get(IInputBuffer buffer)
{
StringBuilder tokenBuilder = new StringBuilder();
char ch;
float numValue = 0; // value of number ignoring
// the decimal point
int wholePlaces = 0; // no. digits before the decimal point
int decimalPlaces = 0; // no. digits after the decimal point
char exponentSign = '+';
float eValue = 0; // value of number after 'E'
int exponent = 0; // final value of exponent
bool sawDotDotFlag = false; // true if encountered '..',
// else false
ch = buffer.CurrentChar;
digitCount = 0;
countError = false;
code = TTokenCode.Error; // we don't know what it is yet, but
type = TDataType.tyInteger; // assume it'll be an integer
//--Get the whole part of the number by accumulating
//--the values of its digits into numValue. wholePlaces keeps
//--track of the number of digits in this part.
if (accumulateValue(buffer, tokenBuilder, ref numValue))
{
wholePlaces = digitCount;
ch = buffer.CurrentChar;
////--If the current character is a dot, then either we have a
////--fraction part or we are seeing the first character of a '..'
////--token. To find out, we must fetch the next character.
if (ch == '.')
{
ch = buffer.GetChar();
if (ch == '.')
{
//--We have a .. token. Back up bufferp so that the
//--token can be extracted next.
sawDotDotFlag = true;
buffer.PutBackChar();
}
else
{
type = TDataType.tyReal;
tokenBuilder.Append(".");
//--We have a fraction part. Accumulate it into numValue.
if (!accumulateValue(buffer, tokenBuilder, ref numValue)) return;
// get the current character
ch = buffer.CurrentChar;
decimalPlaces = digitCount - wholePlaces;
}
}
//--Get the exponent part, if any. There cannot be an
//--exponent part if we already saw the '..' token.
if (!sawDotDotFlag && ((ch == 'E') || (ch == 'e')))
{
type = TDataType.tyReal;
tokenBuilder.Append(ch);
ch = buffer.GetChar();
//--Fetch the exponent's sign, if any.
if ((ch == '+') || (ch == '-'))
{
exponentSign = ch;
tokenBuilder.Append(ch);
ch = buffer.GetChar();
}
//--Accumulate the value of the number after 'E' into eValue.
digitCount = 0;
if (!accumulateValue(buffer, tokenBuilder, ref eValue)) return;
ch = buffer.CurrentChar;
if (exponentSign == '-') eValue = -eValue;
}
//--Were there too many digits?
if (countError)
{
return;
}
//--Calculate and check the final exponent value,
//--and then use it to adjust the number's value.
exponent = (int)eValue - decimalPlaces;
if ((exponent + wholePlaces < -maxExponent) ||
(exponent + wholePlaces > maxExponent))
{
return;
}
if (exponent != 0)
{
numValue *= (float)Math.Pow(10.0, exponent);
}
//--Check and set the numeric value.
if (type == TDataType.tyInteger)
{
if ((numValue < -maxInteger) || (numValue > maxInteger))
{
return;
}
value.integerValue = (int)numValue;
}
else
{
value.realValue = numValue;
}
tokenString = tokenBuilder.ToString();
code = TTokenCode.Number;
}
}
private bool accumulateValue(IInputBuffer buffer, StringBuilder tokenBuilder, ref float value)
{
char ch = buffer.CurrentChar;
Dictionary<int, CharCode> charCodeMap = CharCodeMapManager.Instance.GetCharacterMap();
//--Error if the first character is not a digit.
if (charCodeMap[ch] != CharCode.Digit)
{
return false; // failure
}
//--Accumulate the value as long as the total allowable
//--number of digits has not been exceeded.
do
{
tokenBuilder.Append(ch);
if (++digitCount <= maxDigitCount)
{
value = 10 * value + (ch - '0'); // shift left and add
}
else countError = true; // too many digits, but keep reading anyway
ch = buffer.GetChar();
} while (charCodeMap[ch] == CharCode.Digit);
return true; // success
}
public override void Get(IInputBuffer buffer)
{
char ch = buffer.CurrentChar;
StringBuilder tokenBuilder = new StringBuilder();
tokenBuilder.Append(ch);
switch (ch)
{
case '^': code = TTokenCode.UpArrow; buffer.GetChar(); break;
case '*': code = TTokenCode.Star; buffer.GetChar(); break;
case '(': code = TTokenCode.LParen; buffer.GetChar(); break;
case ')': code = TTokenCode.RParen; buffer.GetChar(); break;
case '-': code = TTokenCode.Minus; buffer.GetChar(); break;
case '+': code = TTokenCode.Plus; buffer.GetChar(); break;
case '=': code = TTokenCode.Equal; buffer.GetChar(); break;
case '[': code = TTokenCode.LBracket; buffer.GetChar(); break;
case ']': code = TTokenCode.RBracket; buffer.GetChar(); break;
case ';': code = TTokenCode.Semicolon; buffer.GetChar(); break;
case ',': code = TTokenCode.Comma; buffer.GetChar(); break;
case '/': code = TTokenCode.Slash; buffer.GetChar(); break;
case ':': // : or :=
ch = buffer.GetChar();
if (ch == '=')
{
tokenBuilder.Append(ch);
code = TTokenCode.ColonEqual;
buffer.GetChar();
}
else
{
code = TTokenCode.Colon;
}
break;
case '<':
ch = buffer.GetChar(); // < or <= or <>
if (ch == '=')
{
tokenBuilder.Append('=');
code = TTokenCode.Le;
buffer.GetChar();
}
else if (ch == '>')
{
tokenBuilder.Append(ch);
code = TTokenCode.Ne;
buffer.GetChar();
}
else
{
code = TTokenCode.Lt;
}
break;
case '>':
ch = buffer.GetChar(); // > or >=
if (ch == '=')
{
tokenBuilder.Append('=');
code = TTokenCode.Ge;
buffer.GetChar();
}
else
{
code = TTokenCode.Gt;
}
break;
case '.':
ch = buffer.GetChar(); // . or ..
if (ch == '.')
{
tokenBuilder.Append(ch);
code = TTokenCode.DotDot;
buffer.GetChar();
}
else
{
code = TTokenCode.Period;
}
break;
default:
code = TTokenCode.Error; // error
buffer.GetChar();
break;
}
tokenString = tokenBuilder.ToString();
}