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Subject: Re: [boost] [pool2] Requests for comment
From: Klaim - Joël Lamotte (mjklaim_at_[hidden])
Date: 2012-10-18 05:27:58

On Thu, Oct 18, 2012 at 8:15 AM, DUPUIS Etienne <e.dupuis_at_[hidden]> wrote:

> If I understand correctly, your 'pool' manages live objects, i.e. objects
> that are currently in use by the application. I was rather working on a
> pool which manages memory for object allocation; i.e. as soon as an object
> is released back to the pool, it's content is destroyed and lost; hence
> there is no way to index elements released to the pool as we can think of
> them as if they no longer exists.

Currently it manage live boost::optional objects, which have constructed or
not the object they wrap, which is the same to say it manage raw memory
which have an object constructed or not, which is I believe exactly what
you describe as a pool.
So I need objects to have specific address (for fast access), not move in
memory, and be destroyed when not used but the memory is still allocated
and ready for another object to be created in.
I also need to go through all the live objects for updates. Assuming I'm
using a vector or stable_vector, it is faster to just go through all
elements from begin to end and check if it's a live object, and if it is to
update it.
If I was using a boost::pool, I would be forced to have, say, a
std::vector<T*> which would have contained only pointers to live objects
and would have to be updated when objects are created or destroyed.
As stable_vector provide iterators to go through all the elements, I don't
need to do this at the moment.

It's ok to me if a pool system don't have a way to go through all the
objects, or a way to go through all the live objects.
However I always have to setup such system at some points when I need a
pool, most of the time by encapsulating the pool in a factory class that
does the job.

Joel Lamotte

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