Re: [PATCH 11/11] cutils: Improve qemu_strtosz handling of fractions

[Hanna Czenczek]

On 10.05.23 09:46, Hanna Czenczek wrote:
> On 09.05.23 23:28, Eric Blake wrote:

[...]

> > But I think the solution to that is not to treat underflow as valf =
> > 0, but rather to alter this snippet:
> >
> > -            valf = (uint64_t)(fraction * 0x1p64);
> > +            /*
> > +             * If fraction was non-zero, add slop small enough that 
> > it doesn't
> > +             * impact rounding, but does let us reject 
> > "1..00000000000000000001B".
> > +             */
> > +            valf = (uint64_t)(fraction * 0x1p64) | !fraction;
> >
> > so that between the ERANGE branch and this slop, valf is guaranteed
> > non-zero if fraction contained any non-zero digits.
>
> I’d make it a logical || instead of |, but that sounds good, yes.

Sent too soon – exactly when sending I realized that I’m very wrong.  
Still, I wouldn’t just | the 1 on, and rather make take the LoC to make it

valf = (uint64_t)(fraction * 0x1p64);
if (!valf && fraction) {
    /*
     * If fraction was non-zero, add slop small enough that it doesn't
     * impact rounding, but does let us reject "1..00000000000000000001B".
     */
    valf = 1;
}