id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6095	boost::icl::is_empty fails for certain open intervals	Marvin Sielenkemper <m.sielenkemper@…>	Joachim Faulhaber	"While playing around with intervals over {{{int}}} with {{{INT_MAX}}} and {{{INT_MIN}}} bounds, I encountered some assertion failures in the library. After a little debugging the problem boiled down to the following test:

{{{
    BOOST_AUTO_TEST_CASE(isEmptyTest)
    {
        typedef int                         Value;
        typedef boost::icl::interval<Value> Interval;
        typedef std::numeric_limits<Value>  Limits;

        Value const max(Limits::max());

        BOOST_CHECK(!is_empty(Interval::open(max - 2, max)));
        BOOST_CHECK( is_empty(Interval::open(max - 1, max)));
        BOOST_CHECK( is_empty(Interval::open(max,     max)));
    }
}}}

The last check fails due to an integer overflow in the implementation of {{{is_empty}}} where the lower bound gets incremented.

I was able to fix this problem for {{{is_empty}}} but there are many places in the ICL where {{{domain_next}}} or {{{domain_prior}}} is used and there might be more problems lurking there.

My motivation for these experiments was to get a properly total interval map, i.e. one where the iterators start at {{{INT_MIN}}} and end at {{{INT_MAX}}}. To get this, I 'primed' the empty map with a closed interval ranging over the complete domain value range. But then the problems started.

So at least for me these overflow problems are not just of academical interest."	Bugs	closed	Boost 1.48.0	ICL	Boost 1.47.0	Problem	fixed	icl, open interval, integer overflow