[boost] [multi-index?] Advice about publicizing capacity for sets/vectors

From: Daryle Walker (darylew_at_[hidden])
Date: 2007-07-17 16:24:39

I was thinking of using a multi-indexed container as part of an
implementation of another container.  The final container will have an
interface like a set, but internally the elements sometimes have to be
accessible via random-access iteration[1].  Implementing with a straight
set would limit me to bidirectional iteration, which will slow down
internal operations that need random access.

The internal multi-index container would have set and vector aspects,
i.e. ordered-unique and random-access index specifiers.  Even though the
external interface will be like a set, should I have publicize the
vector-like operations "capacity" and "reserve"?  Will reserving
capacity help in the ordered-unique part of any insertions?

Alternatively, is there a better way to implement a set w/ random-access
iteration besides this multi-index idea?

[1] I think that the external iterators should stay bidirectional.  That
way I can transfer the ordered-unique view's iterators and give a
consistent traversal order.  If I use the random-access view's
iterators, I could traverse better but there'll be no obvious rule to
the arrangement of elements from the user's perspective.

-- 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT hotmail DOT com