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

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From: Mattias Engdegård <mattias.engdegard <at> gmail.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 58168 <at> debbugs.gnu.org
Subject: bug#58168: string-lessp glitches and inconsistencies
Date: Fri, 14 Oct 2022 16:39:55 +0200

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 also suggested to try memmem as yet another possibility

There is no reason to believe that this would help in any way.

> This is me being happy.

Thank you, let's both rejoice then! Again, the improvements and analyses have been worthwhile.

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