Clear should cause memory size to shrink

Calling clear on an unordered (multi) set or map not only clears all elements but reduces the hash table size.

src/unordered_map.c

@@ -350,8 +350,11 @@ bool unordered_map_remove(unordered_map me, void *const key)
  * Clears the elements from the unordered map.
  *
  * @param me The unordered map to clear.
+ *
+ * @return 0       No error.
+ *         -ENOMEM Out of memory.
  */
-void unordered_map_clear(unordered_map me)
+int unordered_map_clear(unordered_map me)
 {
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
@@ -365,6 +368,14 @@ void unordered_map_clear(unordered_map me)
         me->buckets[i] = NULL;
     }
     me->size = 0;
+    me->capacity = STARTING_BUCKETS;
+    struct node **temp = calloc((size_t) me->capacity, sizeof(struct node *));
+    if (temp == NULL) {
+        return -ENOMEM;
+    }
+    free(me->buckets);
+    me->buckets = temp;
+    return 0;
 }
 
 /**

src/unordered_map.h

@@ -46,7 +46,7 @@ bool unordered_map_contains(unordered_map me, void *key);
 bool unordered_map_remove(unordered_map me, void *key);
 
 // Ending
-void unordered_map_clear(unordered_map me);
+int unordered_map_clear(unordered_map me);
 unordered_map unordered_map_destroy(unordered_map me);
 
 #endif /* CONTAINERS_UNORDERED_MAP_H */

src/unordered_multiset.c

@@ -346,8 +346,11 @@ bool unordered_multiset_remove(unordered_multiset me, void *const key)
  * Clears the elements from the unordered multi-set.
  *
  * @param me The unordered multi-set to clear.
+ *
+ * @return 0       No error.
+ *         -ENOMEM Out of memory.
  */
-void unordered_multiset_clear(unordered_multiset me)
+int unordered_multiset_clear(unordered_multiset me)
 {
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
@@ -361,6 +364,14 @@ void unordered_multiset_clear(unordered_multiset me)
     }
     me->size = 0;
     me->used = 0;
+    me->capacity = STARTING_BUCKETS;
+    struct node **temp = calloc((size_t) me->capacity, sizeof(struct node *));
+    if (temp == NULL) {
+        return -ENOMEM;
+    }
+    free(me->buckets);
+    me->buckets = temp;
+    return 0;
 }
 
 /**

src/unordered_multiset.h

@@ -46,7 +46,7 @@ bool unordered_multiset_contains(unordered_multiset me, void *key);
 bool unordered_multiset_remove(unordered_multiset me, void *key);
 
 // Ending
-void unordered_multiset_clear(unordered_multiset me);
+int unordered_multiset_clear(unordered_multiset me);
 unordered_multiset unordered_multiset_destroy(unordered_multiset me);
 
 #endif /* CONTAINERS_UNORDERED_MULTISET_H */

src/unordered_set.c

@@ -313,8 +313,11 @@ bool unordered_set_remove(unordered_set me, void *const key)
  * Clears the elements from the unordered set.
  *
  * @param me The unordered set to clear.
+ *
+ * @return 0       No error.
+ *         -ENOMEM Out of memory.
  */
-void unordered_set_clear(unordered_set me)
+int unordered_set_clear(unordered_set me)
 {
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
@@ -327,6 +330,14 @@ void unordered_set_clear(unordered_set me)
         me->buckets[i] = NULL;
     }
     me->size = 0;
+    me->capacity = STARTING_BUCKETS;
+    struct node **temp = calloc((size_t) me->capacity, sizeof(struct node *));
+    if (temp == NULL) {
+        return -ENOMEM;
+    }
+    free(me->buckets);
+    me->buckets = temp;
+    return 0;
 }
 
 /**

src/unordered_set.h

@@ -44,7 +44,7 @@ bool unordered_set_contains(unordered_set me, void *key);
 bool unordered_set_remove(unordered_set me, void *key);
 
 // Ending
-void unordered_set_clear(unordered_set me);
+int unordered_set_clear(unordered_set me);
 unordered_set unordered_set_destroy(unordered_set me);
 
 #endif /* CONTAINERS_UNORDERED_SET_H */