Re: Overflow checks and integral vars comparison

Hey Rowan, Yup, I get it now. Sorry for the confusion. I actually remember fixing a similar bug in pdo_sqlite a while back where casting/translation between the two sizes caused such an issue. So I think this would be pretty helpful. On Sun, Aug 23, 2015 at 6:28 PM, Rowan Collins <rowan.collins@gmail.com> wrote: > On 22/08/2015 02:38, Sherif Ramadan wrote: > >> I see. So you're not actually doing overflow checks then? Because at the >> point you'd be checking this zend_long or size_t it could have already >> overflowed or wrapped. The subject may have misled me to understand >> differently. >> > > I think I understand the confusion: you are thinking of overflow as > something which happens *within* a type based on some operation (addition, > multiplication, etc). > > Anatol is talking about overflows which occur when casting *between* > types: a value of 2^33 can safely be passed around as a 64-bit integer, no > overflow has occurred; but attempting to cast it to a 32-bit integer will > immediately overflow the 32-bit integer. > > Since many PHP extensions are wrappers around libraries which may only > deal in 32-bit types, this cast is common, necessitating range checks like > the ones proposed. > > Regards, > > -- > Rowan Collins > [IMSoP] > > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >