> Original Message
> From: Martin Sebor [mailto:msebor@gmail.com] On Behalf Of Martin Sebor
> Sent: Wednesday, December 19, 2007 6:27 PM
> To: stdcxxdev@incubator.apache.org
> Subject: Re: svn commit: r605548  in
> /incubator/stdcxx/branches/4.2.x/include: rw/_defs.h
> rw/_specialized.h sstream string
> incubator/stdcxx/branches/4.2.x/include/rw/_specialized.h Wed Dec
> > +++ 19 06:19:33 2007
> > @@ 69,8 +69,12 @@
> > {
> > typedef _RWSTD_CONTAINER_SIZE_TYPE _RWSizeT;
> >
> >  _RWSizeT __cap = _RWSTD_STATIC_CAST (_RWSizeT,
> >  __size *
> _RWSTD_NEW_CAPACITY_RATIO);
> > + const _RWSizeT __ratio = _RWSizeT (
> (_RWSTD_NEW_CAPACITY_RATIO << 10)
> > + / _RWSTD_RATIO_DIVIDER);
> > +
> > + const _RWSizeT __cap = (__size >> 10) * __ratio
> > + + (((__size & 0x3ff) * __ratio) >> 10);
> > +
>
> Sorry to bringing this up only now that you've committed it...
>
> Would it make sense to make __ratio a global macro instead of
> repeating the same computation in several places?
But we have two __ratio's: __ratio for _RWSTD_NEW_CAPACITY_RATIO
and __ratio for _RWSTD_STRING_CAPACITY_RATIO.
> Also, since
> the divider is used only in the computation of the ratio and
> since we're hardcoding the 10 in the left shift, it sees we
> might as well hardcode the 1000 and forget the divider.
The 10 in left shift is related to the ">> 10" and "& 0x3ff"
operations, but 1000 value is independent from them.
We can define _RWSTD_NEW_CAPACITY_RATIO as 16180
and use 10000 instead of 1000 (i.e. if the _RWSTD_NEW_CAPACITY_RATIO
will contain the 5 significant digits).
Are we need the possibility to change the _RWSTD_NEW_CAPACITY
value to some other? Or we can assume that this value is fixed?
Farid.
