Re: [RFC] Add fast path for strcoll and strcasecmp

[Leonhard Holz <leonhard dot holz at web dot de>]

Am 25.11.2014 21:36, schrieb OndÅej BÃlka:
> On Tue, Nov 25, 2014 at 09:04:04PM +0100, Leonhard Holz wrote:
> > Am 24.11.2014 00:47, schrieb OndÅej BÃlka:
> > > On Sun, Nov 23, 2014 at 11:52:06PM +0100, Leonhard Holz wrote:
> > > > Hi OndÅej,
> > > >
> > > > as far as I understood, the current strcoll implementation scans
> > > > both strings for collation sequences and compares the weights of
> > > > them, whereby a collation sequence can be multiple bytes long. So
> > > > whatever strcmp_l returns as index, you would need a general way of
> > > > finding the start of the collation sequence this index is in.
> > > > Unfortunately I cannot tell if or how this can be done.
> > > As I wrote below you do not have to do that. Just precompute a table that
> > > is zero for characters that are part of some collation sequence and use
> > > old method when one of compared characters is in that table.
> >
> > Ok, I understand the idea and it would be great if it worked. BTW do
> > you know how UTF-8 chars above 7F are handled?
> A UTF-8 char consist of starting byte larger than 0xbf followed by
> characters in 0x80-0xbf range, see
>
> http://en.wikipedia.org/wiki/UTF-8

Sorry for confusion. The question was ought to ask how the algorithm 
handles them. E.g. what to do when strcmp stops at a char with value 0x81.