Re: [PATCH 3/3] pretty=format: Avoid some expensive calculations when not needed

From: Pierre Habouzit <madcoder@debian.org>
Date: Nov 7, 2007, 23:31 UTC
Message-ID: <20071107233145.GB5483@artemis.corp>
In-Reply-To: <4732487A.4050100@lsrfire.ath.cx>

On Wed, Nov 07, 2007 at 11:21:30PM +0000, René Scharfe wrote:

Show 20 quoted lines

> Pierre Habouzit schrieb:
> > {
> >     const char *percent = strchrnul(fmt, '%');
> >     while (*percent) {
> >         strbuf_add(sb, fmt, percent - fmt);
> >         fmt = percent + 1;
> > 
> >         /* do your stuff */
> > 
> >         percent = strchrnul(fmt, '%');
> >     }
> >     strbuf_add(sb, fmt, percent - fmt);
> > }
> > 
> > 
> > Which would require strchrnul, but it's trivial compat/ material for sure.
> 
> Grepping through the source I see several places that can be simplified
> by converting them to strchrnul(), so I think introducing this GNU
> extension is a good idea in any case.

  Yes, strchrnul is _very_ useful for parsing.

> Using strchr()/strchrnul() instead of strbuf_addch()'ing is sensible, of
> course.  I don't like the duplicate code in your sketch above, though.
> I'll try to look into it later today.

Well you can alternatively write it this way of course:

for (;;) {
    const char *percent = strchrnul(fmt, '%');
    strbuf_add(sb, fmt, percent - fmt);
    if (!*percent)
        break /* or return probably */;
    fmt = percent + 1;

    /* do your stuff */
}

-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org