FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

> From: Frediano Ziglio [mailto:freddyz77 AT tin.it]
> Sent: March 17, 2003 2:55 PM
> Il lun, 2003-03-17 alle 20:21, Rusty Wright ha scritto:
> > 
> > I find the style of the "for" loop odd with the space test, and it's
> > wasteful of cpu cycles with it continually assigning to len.  The
> > typical way I'd do this is
> > 
> >   for (i = len; i > 0; i--) {
> >     if (dres.c[i] != ' ')
> >             break;
> >   }
> >   len = i - 1;
> > 
> > I don't think I've got the initial value of "i" correct; you had it
> > set to len-1, but you get the idea; move the test for the space into
> > the body of the loop and only assign to len after the loop finishes.
> 
> In first iteration you test dres.c[len] != ' '... read buffer overflow
> and possible core. If len == 0 after assign len == -1...
> 
> Perhaps better is
> 
> for(i = len; --i >= 0; )
>       if (dres.c[i] != ' ')
>               break;
> len = i + 1;

Why not remove 'i':  

        for( ; len && dres.c[len-1] == ' '; len--);

Rusty, you mentioned CPU cycles.  Does any of this affect the compiler's
assembly output?  I haven't checked. 

--jkl


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