Re: [boost] Re: Re: [circular buffer review]

From: Jan Gaspar (jano_gaspar_at_[hidden])
Date: 2004-03-14 16:26:51

--- Thorsten Ottosen <nesotto_at_[hidden]> wrote:
> > > > > I guess a deque cannot guarantee sequential
> data. Or
> > > > > could it with a special
> > > > > allocator?
> > > > I don't understand this question.
> > >
> > > I mean a vector and a circular_buffer can pass a
> pointer to their data
> to
> > > C-style functions.
> > > A deque cannot because it's data is not
> guaranteed to be sequential. The
> > > question is if
> > > a deque could provide this guarantee somehow
> using eg. a special
> > allocator.
> >
> >    A deque can't.  From the way it is specified,
> it more-or-less has to be
> > implemented as several fixed-size buffers, plus a
> control structure to
> tell
> > which buffer is being used when.
> 
> then what about one big fixed-sized buffer? Can't
> the allocator determine
> the buffer size?
> 
> >A circular_buffer really can't be passed to
> > a C-style function either.  What if the data
> starts in the middle and
> wraps
> > around the end?
> 
> You would have to call data(), right?
> 
Yes you're right.

I just want to mention one more problem with deque.
With deque as underlying container of the
circular_buffer, you have no or very limited control
over iterator invalidation.

Best regards,

Jan

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