[antlr-interest] Bug with C++ charVocabulary option

[Ric Klaren]

Hi,

Should have scanned my whole mailbox before answering previous mail :P

On Thu, May 30, 2002 at 04:50:26PM -0600, Trey Spiva wrote:
> el fits in the range of the vocabulary.  When el is cast to unsigned int the
> value becames 
> 42949667189 and fails the test.  So, BitSet::member return that the
> character is not in
> the charVocabulary.
>  
> When BitSet::member is change to look like
>  
> bool BitSet::member(int el) const
> {
>    unsigned char tempEL = (unsigned char)el;
>    if ( tempEL < 0 || static_cast<unsigned int>(tempEL) >= storage.size())
>             return false;
>  
>    return storage[tempEL];
> }

Change it to:

bool BitSet::member(unsigned int el) const
{
	if ( el >= storage.size())
		return false;

	return storage[el];
}

Also the add method:

void BitSet::add(unsigned int el)
{
	if( el >= storage.size() )
		storage.resize( el+1, false );

	storage[el] = true;
}

Hmmmm basically the complete LA(x) traject needs to be made unsigned int,
else we'll keep on having sign extension issues. It's something I already
noted as potential trouble. Your probably the first to really stumble on
it. Another approach is maybe adding a & 0xFF in a few places to strip away
sign extenstions....

Cheers,

Ric
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    ---- Ric Klaren ----- klaren at cs.utwente.nl ----- +31 53 4893722  ----
-----+++++*****************************************************+++++++++-------
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