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[Python-Dev] issues with int/long on 64bit platforms - eg stringobject (PR#306)
M.-A. Lemburgmal@lemburg.com
Sat, 29 Apr 2000 14:50:07 +0200
Trent Mick wrote:>> > > Guido van Rossum wrote:> > > >> > > > The email below is a serious bug report. A quick analysis shows that> > > > UserString.count() calls the count() method on a string object, which> > > > calls PyArg_ParseTuple() with the format string "O|ii". The 'i'> > > > format code truncates integers. It probably should raise an overflow> > > > exception instead. But that would still cause the test to fail --> > > > just in a different way (more explicit). Then the string methods> > > > should be fixed to use long ints instead -- and then something else> > > > would probably break...> > >> MAL wrote:> > > All uses in stringobject.c and unicodeobject.c use INT_MAX> > > together with integers, so there's no problem on that side> > > of the fence ;-)> > >> > > Since strings and Unicode objects use integers to describe the> > > length of the object (as well as most if not all other> > > builtin sequence types), the correct default value should> > > thus be something like sys.maxlen which then gets set to> > > INT_MAX.> > >> > > I'd suggest adding sys.maxlen and the modifying UserString.py,> > > re.py and sre_parse.py accordingly.> >> Guido wrote:> > Hm, I'm not so sure. It would be much better if passing sys.maxint> > would just WORK... Since that's what people have been doing so far.> >>> Possible solutions (I give 4 of them):> [...]Here is another one... I don't really like it because I think thatsilent truncations are a bad idea, but to make things "just workit would help:* Change PyArg_ParseTuple() to truncate the range(INT_MAX+1, LONG_MAX+1) to INT_MAX and the same for negative numbers when passing a Python integer to a "i" marked variable. This would map range(INT_MAX+1, LONG_MAX+1) to INT_MAX and thus sys.maxint would turn out as INT_MAX in all those cases where "i" is used as parser marker. Dito for negative values.With this truncation passing sys.maxint as default argumentfor length parameters would "just work" :-).The more radical alternative would be changing the Pythonobject length fields to long -- I don't think this ispractical though (and probably not really needed unlessyou intend to work with 3GB strings ;).-- Marc-Andre Lemburg______________________________________________________________________Business:http://www.lemburg.com/Python Pages:http://www.lemburg.com/python/
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