6. Re: map with minimal memory footprint (David Abrahams) Date: Wed, 16 Mar 2005 09:45:34 -0500 From: David Abrahams <dave@boost-consulting.com> Subject: [Boost-users] Re: map with minimal memory footprint To: boost-users@lists.boost.org Message-ID: <uoedjd4z5.fsf@boost-consulting.com> Content-Type: text/plain; charset=us-ascii
Toon Knapen <toon.knapen@fft.be> writes:
Hi all,
I'm using a rather big std::map which gives good performance but the memory footprint is a bit too big. So I figured to implement an std::map as an std::vector<std::pair<T1,T2>> but thus with the interface of an std::map on top of it.
Can't be done. It has the wrong iterator invalidation properties. You may be able to implement a useful associative container, but it will never be std::map.
-- Dave Abrahams Boost Consulting www.boost-consulting.com
I believe you, but can you explain what you mean by "iterator invalidation properties". I wrote a vector_map once, and it was as "map-ish" as needed at the time, so I suspect it was just a "useful associative container", but I'm just curious as to what I was missing...