[PATCH 1/2] comctl32/listbox: Fix InitStorage heap extension

[Gabriel Ivăncescu]

Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
---

Only increase the item array if we actually have to. Previously, sending 1 to
nb_items repeatedly would always increase the array by LB_ARRAY_GRANULARITY,
even if there was plenty of space.

 dlls/comctl32/listbox.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/dlls/comctl32/listbox.c b/dlls/comctl32/listbox.c
index 2137ef8..9cd89ff 100644
--- a/dlls/comctl32/listbox.c
+++ b/dlls/comctl32/listbox.c
@@ -673,16 +673,20 @@ static LRESULT LISTBOX_InitStorage( LB_DESCR *descr, INT nb_items )
 {
     LB_ITEMDATA *item;
 
-    nb_items += LB_ARRAY_GRANULARITY - 1;
-    nb_items -= (nb_items % LB_ARRAY_GRANULARITY);
     if (descr->items) {
-        nb_items += HeapSize( GetProcessHeap(), 0, descr->items ) / sizeof(*item);
-	item = HeapReAlloc( GetProcessHeap(), 0, descr->items,
-                              nb_items * sizeof(LB_ITEMDATA));
+        nb_items += descr->nb_items;
+        if (nb_items > HeapSize(GetProcessHeap(), 0, descr->items) / sizeof(*item))
+        {
+            UINT n = nb_items + LB_ARRAY_GRANULARITY - 1;
+            item = HeapReAlloc(GetProcessHeap(), 0, descr->items,
+                               (n - n % LB_ARRAY_GRANULARITY) * sizeof(*item));
+        }
+        else return LB_OKAY;
     }
     else {
-	item = HeapAlloc( GetProcessHeap(), 0,
-                              nb_items * sizeof(LB_ITEMDATA));
+        UINT n = nb_items + LB_ARRAY_GRANULARITY - 1;
+        item = HeapAlloc(GetProcessHeap(), 0,
+                         (n - n % LB_ARRAY_GRANULARITY) * sizeof(*item));
     }
 
     if (!item)
-- 
1.9.1