Re: [boost] Re: Cycle Iterator Adapter (was: Re: Help with iterator helpers)

From: Thomas Witt (witt_at_[hidden])
Date: 2002-02-05 10:57:37

On Tuesday 05 February 2002 16:37, you wrote:
> In increment:
>
>  if( ++x.base() == m_bounds.second )
>             x.base() = m_bounds.first;
>
>
> Since m_bounds.second is not included in the range, shouldn't that be:
>
>  if( x.base()++ == m_bounds.second )
>             x.base() = m_bounds.first;
>

I don't think so. AFAICS

if( x.base()++ == m_bounds.second )

would not prevent us fom incrementing the end iterator.

It is 

if( ++x.base() == m_bounds.second )
            x.base() = m_bounds.first;

because m_bounds.second is not included in the range so we have to make
sure base does not point to m_bounds.second.

As I am writing this: If you question was should m_bounds.second  be a valid 
position for the cyclic iterator? I think no. To me providing a half open 
range to the policies constructor is the right way to go. Otherwise we would 
surely confuse users.

Thomas

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-- 
Dipl.-Ing. Thomas Witt
Institut fuer Verkehrswesen, Eisenbahnbau und -betrieb, Universitaet Hannover
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