} // AddString
// If the current position of the TextReaderBuffer matches any
// of our registered strings, then set length to the length of the
// longest such string, set info to the value supplied in AddString,
// and return true. Otherwise leave length and info undefined, and
// return false.
public bool Match(TextReaderBuffer reader, out int length, out int info)
{
// We don't really need to assign length and info here, but we do so
// so that the compiler won't complain on any of the "return false"
// paths.
length = 0;
info = 0;
char[] buffer;
int bufStart;
int bufLen = reader.GetBuffer(maxLen, out buffer, out bufStart);
if (bufLen <= 0)
{
return(false);
}
// NOTE (snewman 7/12/01): this is currently implemented as a
// simple linear search over all registered strings, after
// discriminating by the initial character. Many more efficient
// algorithms are possible, such as binary search or tries. Doesn't
// seem worthwhile.
int initialChar = buffer[bufStart];
bufStart++;
bufLen--;
if (initialChar >= strings.Length)
{
return(false);
}
for (StringEntry candidate = strings[initialChar];
candidate != null; candidate = candidate.next)
{
if (bufLen >= candidate.headlessString.Length &&
MatchChars(buffer, bufStart, candidate.headlessString))
{
if (!candidate.isIdentifier ||
bufLen == candidate.headlessString.Length ||
!CharUtils.IsIdentifierChar(buffer[bufStart + candidate.headlessString.Length]))
{
length = candidate.headlessString.Length + 1;
info = candidate.info;
return(true);
}
}
}
return(false);
} // Match
} // ParseStringLiteral
// Advance the stream past a comment beginning at the current stream
// location.
private void SkipComment(SrcLoc loc)
{
// HACK SN 7/13/01: rewrite this to support comments longer
// than maxTokenLen.
// Get a buffer from which we can parse the comment.
char[] charBuf;
int startPos;
int bufLen = buffer.GetBuffer(maxTokenLen, out charBuf,
out startPos);
int tokenLen = 2;
if (charBuf[startPos + 1] == '/')
{
// C++ style comment; search for end of line
while (tokenLen < bufLen &&
!CharUtils.IsEOLChar(charBuf[startPos + tokenLen]))
{
tokenLen++;
}
}
else
{
// C style comment; search for "*/"
// NOTE: we might extend this to warn for nested comments.
while (tokenLen < bufLen - 1 &&
(charBuf[startPos + tokenLen] != '*' ||
charBuf[startPos + tokenLen + 1] != '/'))
{
tokenLen++;
}
if (tokenLen >= bufLen - 1)
{
loc.len = tokenLen;
throw new ParseError("unterminated /* comment", loc);
}
// Include the trailing "*/" in tokenLen.
tokenLen += 2;
}
buffer.Skip(tokenLen);
} // SkipComment
} // SkipComment
// Advance the stream past a block of whitespace beginning at the
// current stream location.
//
// NOTE: the current implementation of this method will only skip
// up to one buffer's worth of whitespace. This simplifies the
// implementation, and is OK because we'll just skip any remaining
// whitespace in the next go-around of the tokenizer loop.
private void SkipWhitespace()
{
// Get a buffer from which we can search for whitespace.
char[] charBuf;
int startPos;
int bufLen = buffer.GetBuffer(maxTokenLen, out charBuf,
out startPos);
int tokenLen = 1;
while (tokenLen < bufLen &&
CharUtils.IsWhitespaceChar(charBuf[startPos + tokenLen]))
{
tokenLen++;
}
buffer.Skip(tokenLen);
} // SkipWhitespace
} // ParseIdentifier
// Parse a numeric literal beginning at the current stream location.
private Token ParseNumber(SrcLoc loc)
{
// Get a buffer from which we can parse the number.
char[] charBuf;
int startPos;
int bufLen = buffer.GetBuffer(maxTokenLen, out charBuf,
out startPos);
if (bufLen > maxTokenLen)
{
bufLen = maxTokenLen;
}
// Find the end of the number. We match for the following
// components:
//
// integer part (1 or more digits)
// optional fractional part ('.' plus one or more digits)
// optional exponent ('E' or 'e', optional '+' or '-', and 1-3 digits)
//
// HACK SN 7/14/01: for now, we aren't enforcing that the fractional
// part must have at least one digit, or that the exponent must have
// at least 1 and no more than 3 digits. Review the ECMAScript spec for
// the correct rules. Also, should we allow numbers that begin with a '.'
// (no integer part)?
int tokenLen = 0;
while (tokenLen < bufLen &&
CharUtils.IsDigitChar(charBuf[startPos + tokenLen]))
{
tokenLen++;
}
if (tokenLen < bufLen && charBuf[startPos + tokenLen] == '.')
{
tokenLen++;
while (tokenLen < bufLen &&
CharUtils.IsDigitChar(charBuf[startPos + tokenLen]))
{
tokenLen++;
}
}
if (tokenLen < bufLen &&
(charBuf[startPos + tokenLen] == 'E' ||
charBuf[startPos + tokenLen] == 'e'))
{
tokenLen++;
if (tokenLen < bufLen &&
(charBuf[startPos + tokenLen] == '+' ||
charBuf[startPos + tokenLen] == '-'))
{
tokenLen++;
}
while (tokenLen < bufLen &&
CharUtils.IsDigitChar(charBuf[startPos + tokenLen]))
{
tokenLen++;
}
}
NumLit token = new NumLit();
token.rawText = buffer.ConsumeString(tokenLen);
loc.len = tokenLen;
token.loc = loc;
try
{
token.value = Double.Parse(token.rawText);
}
catch (FormatException e)
{
throw new ParseError("FormatException parsing numeric literal \"" +
token.rawText + "\": " + e.ToString(),
loc);
}
catch (OverflowException e)
{
throw new ParseError("OverflowException parsing numeric literal \"" +
token.rawText + "\": " + e.ToString(),
loc);
}
return(token);
} // ParseNumber
