Re: Doubts about in_avail vs showmanyc

[Paolo Carlini <pcarlini at unitus dot it>]

Nathan Myers wrote:

> This should end up as:
>  
>
> >    inline streamsize
> >    in_avail()
> >    {
> >      streamsize __ret = this->egptr() - this->gptr();
> >      return (__ret != 0) ? __ret : this->showmanyc();
> >    }
> >    
> In other words, in_avail() doesn't care if there's anything in some
> putback cell; if there is, that's what's available without a call to
> underflow(), and that's what this->gptr() points to, so that's all it
> reports.  In general, you can cut and _cut_ and *cut* the members of
> basic_streambuf<> until they are really easy to understand (and fast).
> Put all complexity into the virtuals of the derived classes where 
> speed is less important, because time spent there is amortized over
> many characters.  
>
> Note that there's no need to test for null pointers because if
> one is 0, the others are 0 too and the difference is 0.
Thanks Nathan for this reply and the other.

In general, "cutting and cutting" really scares me, since, until I'm 
completely sure to understand
the smallest details, I'm _so_ afraid to broke something: I keep asking 
myself: "if someone put
this here, there must be a reason!". A basic example are those checks 
for null pointers: there are
many of them!

You'll have to review attentively any patch I wrote in the near future 
and, in case, reassure me
that I'm doing the right thing.

Paolo.