PATCH: mount -O list

[Michael Abbott]

On Fri, 4 Dec 2009, Denys Vlasenko wrote:
> On Fri, Dec 4, 2009 at 1:48 PM, Michael Abbott <michael at araneidae.co.uk> wrote:
> > On Fri, 4 Dec 2009, walter harms wrote:
> >> Michael Abbott schrieb:
> >> > 3. strchrnul() -- oh, that is nice!  Is that a busybox special function?
> >> > It doesn't seem to be part of glibc.  Of course, makes the step on to the
> >> > next item at the end of the loop slightly more clunky.
> On the contrary, it makes the step smaller. I checked code size.

Intruiging.  

I was only referring to the difference between
	if (!O_comma)
		break;
and
	if (O_opt[O_len] == '\0')
		break;
and now think I was talking nonsense, each is as clear as each other.  Of 
course the first is (potentially) just a register access, while the second 
definitely fetches ram (already seen, so probably in cache), so there is 
some difference.

Of course
	O_len = strchrnul(O_opt, ',') - O_opt;
is going to take up less code (and is *much* clearer) than
	O_comma = strchr(O_opt, ',');
	O_len = O_comma ? O_comma - O_opt : strlen(O_opt);
which I presume is where most of the code size difference you checked came 
from.

But actually I'm completely persuaded: I'll use strchrnul() next time I do 
some parsing.