[PATCH v5 8/8] comctl32/listbox: Shrink the item array in a helper function

[Gabriel Ivăncescu]

On Thu, Nov 22, 2018 at 4:02 PM Huw Davies <huw at codeweavers.com> wrote:
>
> On Thu, Nov 22, 2018 at 03:44:44PM +0200, Gabriel Ivăncescu wrote:
> > Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
> > ---
> >  dlls/comctl32/listbox.c | 33 +++++++++++++++++++--------------
> >  1 file changed, 19 insertions(+), 14 deletions(-)
> >
> > diff --git a/dlls/comctl32/listbox.c b/dlls/comctl32/listbox.c
> > index 3b76e19..41eb631 100644
> > --- a/dlls/comctl32/listbox.c
> > +++ b/dlls/comctl32/listbox.c
> > @@ -148,6 +148,24 @@ static BOOL expand_storage(LB_DESCR *descr, UINT amount)
> >      return TRUE;
> >  }
> >
> > +static void shrink_storage(LB_DESCR *descr)
> > +{
> > +    LB_ITEMDATA *p = descr->items;
> > +    UINT num = descr->nb_items;
> > +
> > +    if (num + LB_ARRAY_GRANULARITY * 2 < descr->array_size)
> > +    {
> > +        num += LB_ARRAY_GRANULARITY - 1;
> > +        num -= num % LB_ARRAY_GRANULARITY;
> > +        p = HeapReAlloc(GetProcessHeap(), 0, p, num * sizeof(LB_ITEMDATA));
> > +        if (p)
> > +        {
> > +            descr->array_size = num;
> > +            descr->items = p;
> > +        }
> > +    }
> > +}
> > +
>
> I was hoping for a common allocation function (resize_storage() say),
> that would take the length of the required array, not one function to
> grow and another to shrink.
>
> Also, let's insist that LB_ARRAY_GRANULARITY is a power of two, to
> simplify these adjustments.
>
> Huw.

I didn't want to change too much in one patch. Also only growing
should give error when failing to allocate (as was the behavior
before). I think adding extra checks for that is going to make the
function uglier than it needs to be, since it will be effectively two
functions in one.