Den 21-05-2011 12:28, Matias Capeletto skrev:
Hi Beman,
On Thu, May 19, 2011 at 5:49 AM, Thorsten Ottosen <thorsten.ottosen@dezide.com> wrote:
Boost.Bimap does something similar. Would it not be possible to do something similar, even though the value is fetched lazily?
I'll look at Bimap. Thanks for the pointer.
In PtrContainer we cache the underlying pair to adjust the interface: template< class F, class S > struct ref_pair { typedef F first_type; typedef S second_type; const F& first; S second; template< class F2, class S2 > ref_pair( const std::pair<F2,S2>& p ) : first(p.first), second(static_cast<S>(p.second)) { } template< class RP > ref_pair( const RP* rp ) : first(rp->first), second(rp->second) { } const ref_pair* const operator->() const { return this; } ... }; Alternatively, it might be slightly more efficient to provide cnoversion operations for dummy objects called first/second. But I doubt it will have any significant overhead in the btree case as I suspect that iteration is already slower than normal in-memory datas tructures. -Thorsten