On 4/7/06, Tom Spear (Dustin Booker, Dustin Navea) <speeddymon@gmail.com> wrote:
> >
> > if (srclen < 0) srclen = strlenW(src) + 1;
> >
> > so we never access the string with a negative index.
> >
>
> Umm, all that does is increment it by 1...  What if _somehow_ (dont ask
> me how, just venturing a guess) a bogus number is passed by strlenW(src)
> like -3789246?  Then you end up with srclen == -3789245...
>

strlen returns a value of type size_t, which is an unsigned value, so
this is always going to be positive.

> > * Negative value can be returned and we don't check for it.
> >
> I could be wrong, but wouldnt it be (theoretically speaking) possible
> for a program to force a negative number out of it (even though it isnt
> supposed to be able to), since it IS an int, regardless of the return
> value type?
>

If I write a function foo(x,y) that returns a signed int, but I only
ever return a value >= 0, then no matter what input the user gives for
x and y, a negative value can never be returned.  The problem is that
MS decided to make the return type of WideCharToMultiByte int instead
of unsigned int, which we can't change.  Let's say hypothetically that
a negative value can be returned in our implementation, then it's
still a bug in WideCharToMultiByte and these Coverity bugs are still
false positives.