Re: [PATCH] globsort: handle int overflow in cmp functions

[Chet Ramey]

On 5/17/24 5:56 PM, Grisha Levit wrote:
> On Fri, May 17, 2024 at 3:06 PM Chet Ramey <chet.ramey@case.edu> wrote:
> > On 5/17/24 12:57 PM, Grisha Levit wrote:
> > > The current cmp implementation for size and blocks subtracts the two
> > > values and returns the difference as an int. This subtraction can
> > > overflow, and the returned int can end up having the wrong sign.
> > >
> > > This also makes the qsort comparison function non-transitive. (Some
> > > interesting discussion on that at [1]).
> >
> > Thanks for the report. If overflow is a concern, then a guaranteed
> > transitive comparison function is the right thing. Your solution is clever,
> > but a little obscure; I think I'll make it look more like the other
> > comparison functions.
>
> FWIW, I was copying the approach from coreutils[1] and gnulib[2]:

Sure. I'm going to stick with code clarity and uniformity over micro
optimizations here. Maybe I could hide it in a macro.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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