Re: [9fans] s_putc and Runes

["Bruce Ellis" <bruce.ellis@gmail.com>]

exactly.  time spent optimizing something that uses 3% of the CPU
by 10% is better spent going to the beach, or almost anything.

On 2/5/07, Russ Cox <rsc@swtch.com> wrote:
> > void
> > s_putrune(String *s, Rune r)
> > {
> >         char rbuf[UTFmax];
> >         s_nappend(s, rbuf, runetochar(rbuf, &r));
> > }
>
> This is fine.
>
> > or as part of the library (where I'm a bit shakier on the semantics):
> >
> > void
> > s_putrune(String *s, Rune r)
> > {
> >         char rbuf[UTFmax];
> >         int n;
> >         if(s->ref > 1)
> >                 sysfatal("can't s_putc a shared string");
> >         if (s->ptr >= s->end - n=runelen(r))
> >                 s_grow(s, n+1);
> >         (s->ptr) += runetochar(s->ptr, &r);
> > }
>
> Why bother with these details?  The above is fine.  If it ever
> became too slow, the right thing to do would be to fix s_nappend,
> not code around everything here.  Further, this code is *very*
> unlikely to be the bottleneck -- you're calling it once per at most
> 3 bytes, so the extra little bit you might or might not be saving
> this way pales in comparison to the added complexity.
>
> The main reason there is no Rune support in the String
> library is that it is not widely used.  It was written for upas
> and later extracted, but the interface is a bit clunky.
>
> I confess that most of the time, when I need to write to a
> growable string buffer, I just use fmtstrinit, fmtprint, and fmtstrflush.
> It's just easier, and you get all the print verbs!
>
> Russ
>