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Date: Tue, 3 Mar 2015 10:54:11 -0500
From: Rich Felker <dalias@...c.org>
To: musl@...ts.openwall.com
Subject: Re: [PATCH] conforming strverscmp() implementation

On Tue, Mar 03, 2015 at 12:45:07PM +0200, Sergey Dmitrouk wrote:
> Hi,
> 
> Attached is strverscmp() that should conform to what is described in
> manual pages.  It's not actually a diff as it would be harder to read
> in this case.
> 
> The idea is just as described in manuals (once you get what they mean):
> 
> 1. Find point where strings differ as in current code, but keep track
>    of locations of last seen numbers.
> 2. If numbers are both integers (that is they don't start with zero or
>    it's a single zero) compare as in current implementation.
> 3. If only one of numbers is integer, the other one is smaller.
> 4. Otherwise, number with longer leading sequence of zeroes is smaller.
> 5. If leading zeroes match, compare characters following last zero in
>    both strings.
> 
> I didn't see much comments in musl, so there is none in this file, but
> can add some if requested.
> 
> Implementation is admittedly more sophisticated than current version for
> the reason that all simpler approaches I tried fail for at least one of
> possible comparison cases.

Thanks. This has been an open issue for a while. I haven't looked at
your code in detail yet and at this point it will probably be
something I do after the 1.1.7 release, and I'd like to allow some
time for review. Have you run libc-test against it and checked that it
fixes all the test failures there? I would guess it does since they're
based on the man page examples but it would be good to double-check
anyway if you haven't.

Rich

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