size: cppuhelper containers ... ~700k

Hi there,

        So - in my ongoing campaign to shrink memory usage, it seems that the
cppuhelper classes use the (uber-stupid) stl::hash_map code that insists
on allocating a staggering amount of memory for an empty hash (as
previously discussed).

        Dumping counts of OMultiTypeInterfaceContainerHelper and it's
Int32 variant extant post writer startup I see:

        IfContainers 507
        IfContainersInt32 388

        I also notice that wrt. the contents of the m_pMap we normally
have very few elements:

count   num elements
    282 1
   2841 2
   1569 3
     38 4

        That is for IfContainers, and -incredibly- none of the
IfContainersInt32 actually have any contents at all ;-) [ I have to load
an impress document to get even a few of them with 1-2 items in them ].

        A hash_map's default size is 193 elements, so we waste:

        (507+388) * (193 - 4) * 4-bytes-per-ptr = 676Kb

The patch:
        http://go-oo.org/ooo-build/patches/src680/size-cppuhelper.diff

        switches from a hash to a vector, which given the size saving, and
small data sets, will almost certainly accelerate things however you
look at it, and saves a chunk of RAM.

        The saving is around 700k by not allocating the (~all empty) Int32
container contents too, numbers from pmap (DIRTY):

Before: 19264 19256 + 19268 + 3 / p : 19262
After:  18552 18552 + 18544 + 3 / p : 18549
Saving: - p                         :   713(k)

        "using STL hash may unexpectedly bloat your world" :-]

        This does of course change some cross-module API - wrt. the inlines in
interfacecontainer.hxx - but I believe this is no longer a big concern
(?).

        Thanks,

                Michael.

-- 
 michael.meeks@xxxxxxxxxx  <><, Pseudo Engineer, itinerant idiot