RE: [Algorithms] fundamentally better containers

[Gribb, G. <gg...@ra...>]

> Hey Gil, how do you do this?  Do you just use a map<> or did
> you write a bunch of your own container code?  It seems like
> making a fixed-size allocator that will work with vector is
> pretty easy, but working with map<> and its whole rebind
> mechanism seems pretty scary.

Well, I certainly wouldn't want to write smap<> from scratch, so I wrote an
allocator to do it. The rebind mechanism and allocators in general in stl
apparently never designed for static allocation, which is unfortunate. 

With some hacky, stl implementation-specific code you can do it. But you
need to know how the stl implementation works. If I were to do it again, I
would probably just use a #define MAP_NODE_EXTRA, which is enough additional
storage for a map node beyond the key and value size. Backedup up with
asserts of course. This is even more hacky, but simpler.

I needed these bad enough that good style wasn't going to get in the way.
And once they are tested, and with appropriate asserts, they are safe and
work very well.

-Gil


> 
> At 09:01 AM 7/31/2001 -0500, Gil wrote:
> >My psx2 engine has no dynamic memory allocation at all. It uses STL
> >extensively, but with static allocators, so for example:
> >
> >void foo()
> >{
> >         smap<float,CCollisionRecord,32> Collisions;
> >         ....
> >}
> 
> ----------------------------------------------------
> Charles Bloom    cb...@cb...    www.cbloom.com
> 
> 
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