[boost] Pool Iterators?

From: Geoff Leyland (geoff.leyland_at_[hidden])
Date: 2002-11-08 03:33:14

Hi,

I'm using boost::pool for (evidently) allocating memory for a whole 
bunch of objects (thanks Stephen Cleary for pool).  Most of the time the 
objects are entirely independent, however, from time to time, I'd like 
to iterate through all the allocated objects (in this case to generate 
some test statistics over then).  To do this I keep a list of pointers 
to everything I've allocated.  The time spent keeping this list up to 
date, particularly removing an object, is significant.

One possible (and very nice fix) would be to have a pool_iterator that 
let me, as I said, iterated through the allocated objects.  As far as I 
can tell, this doesn't exist.  Does anyone have any comments on whether 
this is a good idea, whether it's feasible, and perhaps how I might go 
about it?

The pools don't seem to have a bit-map of free blocks - and traversing 
the free list at every increment would be horribly slow.  I have a 
"holey_vector" that uses a vector as storage, and keeps a sorted list of 
free indexes, but I can't imagine this approach would work in a pool, 
where the storage is a list of blocks at non-increasing addresses.  
Marking blocks as free at the beginning of the block would take up at 
worst a whole alignment worth of memory, kind of defeating the point of 
the pool.

So I'm guessing the best approach would be a bit map of free blocks.  
Comments?

cheers,
goof

--
Geoff Leyland
Laboratoire d'energetique industrielle
LENI-DGM-EPFL, CH-1015, Lausanne, Switzerland
Phone: [phone], Fax: [phone]