Re: [boost] [utility] new auto_buffer class --- RFC

Subject: Re: [boost] [utility] new auto_buffer class --- RFC
From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2009-03-02 14:59:21

John Bytheway skrev:
> Thorsten Ottosen wrote:
>> Frank Mori Hess skrev:
   Hmm, your
>>> auto_buffer doesn't support swap though.
>> No. As it might be O(n). I'm not against providing "swap()", it should
>> just be under a different name, e.g. liniear_swap().
> 
> Certainly swap should be provided somehow; a fast-as-possible swap is
> not otherwise possible since the user can't get at the buffer pointer.
> boost::array supports swap, and yours should be at least as fast as
> that.  On that precedent I'd say you should support swap() under that
> name.  Has anyone ever complained about the deceptive slowness of
> boost::array's swap?

I don't know. I just stay clear of it. The point is that we don't want
inexperienced users to use an O(n) swap accidently.

> Also, I think the following sort of code is quite plausible:
> 
> std::pair<int, auto_buffer<int, 2> > a,b;
> //...
> swap(a,b);
> 
> (e.g. I often find myself sorting vectors of such pairs) and for that to
> work you need to provide a free swap overload.

Ok. That justifies some way of performing the swap.

-Thorsten