don't grow the hashset if it just clobbered with deleted entries

diff --git a/adt/hashset.c.inl b/adt/hashset.c.inl
index e0cf70c..0e7ce35 100644 (file)
--- a/adt/hashset.c.inl
+++ b/adt/hashset.c.inl
@@ -346,13 +346,20 @@ static inline void resize(HashSet *self, size_t new_size);
  */
 static inline void maybe_grow(HashSet *self)
 {
-       size_t resize_to;
-
        if (LIKELY(self->num_elements + 1 <= self->enlarge_threshold))
                return;
 
-       /* double table size */
-       resize_to = self->num_buckets * 2;
+       size_t resize_to;
+       if (self->num_elements - self->num_deleted + 2 > self->enlarge_threshold) {
+               /* double table size */
+               resize_to = self->num_buckets * 2;
+               if (resize_to <= self->num_buckets) {
+                       abort();
+               }
+       } else {
+               /* no need to resize, we just clean up the deleted entries */
+               resize_to = self->num_buckets;
+       }
        resize(self, resize_to);
 }