Re: Converting access values

[Robert A Duff <bobduff@shell01.TheWorld.com>]

"Randy Brukardt" <randy@rrsoftware.com> writes:

> "Mark Lorenzen" <mark.lorenzen@ofir.dk> wrote in message
> news:m31xcxdnoz.fsf@0x53586c58.boanxx18.adsl-dhcp.tele.dk...
> ...
> ...
> > It solves the problem, but exposes a bit more information to the
> > clients than necessary. It is very easy for a client to address a
> > slice outside the bounds:
> >
> > Buffer.Data (Buffer.First - 10 .. Buffer.Last + 15)
> >
> > But there is of course also the risk of over-engineering the buffer,
> > so I will settle with the above design.
> 
> I understand, but you had said that performance was critically important
> here. When that's the case (and remember that it is very rare that it is),
> you have to toss abstraction and OOP and all of that other good stuff that
> eats ups a bit of performance in favor of getting the job done. So I
> wouldn't worry too much about that small safety hole. (It's perfectly
> reasonable to look for a solution that doesn't give up that stuff, but silly
> to obsess about it.) The important thing is that the code with the guts
> hanging out be limited to a small, critical part of the system, and it seems
> that you are doing that.

Right.  And one can ameliorate the problem with a coding convention:
At the start of each procedure that messes with these things,
declare:

    Buf: ... renames Buffer.Data(Buffer.First..Buffer.Last);

and then refer only to Buf in there.

- Bob