GNU bug report logs - #58168
string-lessp glitches and inconsistencies

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Message #119 received at 58168 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Mattias Engdegård <mattias.engdegard <at> gmail.com>
Cc: 58168 <at> debbugs.gnu.org
Subject: Re: bug#58168: string-lessp glitches and inconsistencies
Date: Fri, 14 Oct 2022 18:31:14 +0300

> From: Mattias Engdegård <mattias.engdegard <at> gmail.com>
> Date: Fri, 14 Oct 2022 16:39:55 +0200
> Cc: 58168 <at> debbugs.gnu.org
> 
> As performance is more acceptable now I'm not going to take any further action with respect of string<, but let me just answer your questions:
> 
> 8 okt. 2022 kl. 09.35 skrev Eli Zaretskii <eliz <at> gnu.org>:
> 
> > I suggested to use memchr to find whether a string has any
> > C0 or C1 bytes, _before_ doing the actual comparison, to find out
> > whether a multibyte string includes any raw bytes, which would then
> > require slower comparisons.
> 
> That isn't practical; we would traverse each argument in full, twice, even if there is a difference early on. While memchr is fast for what it does, it will still need to look at every bit of its input.

I fail to see how the number of times we'd traverse the strings is of
concern, as long as it's fast enough.  And memchr _is_ very fast.

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