Re: avoid possible overflow?

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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Carles Pina i Estany wrote:
> Hello,
>
> The common pattern when doing a search by bisection is something like:
> +      current = min + (max - min) / 2;
>
> Instead of the first natural idea:
> -      current = (max + min) / 2;
>
> To avoid overflows.
>
> In gettext/gettext.c it's used in the "incorrect" way. It's not a big
> problem since would happen only with .mo files with lot of strings, like
> number that int represents in that architecture divided by 2 (aprox
> aprox.).
>
> See the attached file for a patch if we want to patch.
>   
You forgot to make the same change before the loop. But actually it
doesn't matter because overflow in this statement:
  internal_position = offsettranslation + position * 8;
is reached well before the overflow in bisecting. Anyway this
mattersonly for >4GiB files and unless we put videos in .po I don't see
how this limit would be reached. So I prefer readability and would
reject this patch.
> Else I would at least add a comment that we simplified because we
> consider that will not happen.
>
> Thanks,
>
>   
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>
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-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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