Re: [boost] circular_buffer question

From: Jan Gaspar (jano_gaspar_at_[hidden])
Date: 2004-04-13 01:40:03

Hi Neal!

I didn't considered this feature important. Moreover
it would complicate the iterator. Currently these
expressions are invalid:
circular_buffer<int> cb(10);
cb.push_back(1);
// ...
circular_buffer<int>::iterator it1 = cb.end() + 1; //
invalid
circular_buffer<int>::iterator it2 = cb.begin() - 1;
// invalid (see Caveats section in docs)

I think if I allowed negative indexes or indexes "out
of range" I had to change the iterator, too.

On the other hand it is not difficult to create an
adaptor and someone can make one if he needs such
feature.

Best regards,

Jan

--- "Neal D. Becker" <ndbecker2_at_[hidden]> wrote:
> I'm looking at circular_buffer.  It appears to me
> that operator[] uses
> "add", and that "add" only allows a positive value
> of offset?  It is not
> difficult to allow arbitrary values, and this is
> very useful.  
> 
> if "position" is the current "m_first" and
> "allocated" is the allocated
> buffer size, the index could be calculated:
> 
>   int index (int offset) const {
>     int x = (offset + position) % int(allocated);
>     if (x >= 0)
>       return x;
>     else
>       return x + allocated;
>   }
>  
> 
> _______________________________________________
> Unsubscribe & other changes:
http://lists.boost.org/mailman/listinfo.cgi/boostp://lists.boost.org/mailman/listinfo.cgi/boost

        
                
__________________________________
Do you Yahoo!?
Yahoo! Small Business $15K Web Design Giveaway 
http://promotions.yahoo.com/design_giveaway/