diff -r bb17790af41e -r fd3368c20413 src/hash_map.c
--- a/src/hash_map.c	Fri May 27 14:14:55 2022 +0200
+++ b/src/hash_map.c	Fri May 27 17:40:27 2022 +0200
@@ -396,3 +396,52 @@
 
     return (CxMap *) map;
 }
+
+int cxMapRehash(CxMap *map) {
+    struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+    if (map->size > ((hash_map->bucket_count * 3) >> 2)) {
+
+        size_t new_bucket_count = (map->size * 5) >> 1;
+        struct cx_hash_map_element_s **new_buckets = cxCalloc(map->allocator,
+                                                              new_bucket_count, sizeof(struct cx_hash_map_element_s *));
+
+        if (new_buckets == NULL) {
+            return 1;
+        }
+
+        // iterate through the elements and assign them to their new slots
+        cx_for_n(slot, hash_map->bucket_count) {
+            struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
+            while (elm != NULL) {
+                struct cx_hash_map_element_s *next = elm->next;
+                size_t new_slot = elm->key.hash % new_bucket_count;
+
+                // find position where to insert
+                struct cx_hash_map_element_s *bucket_next = new_buckets[new_slot];
+                struct cx_hash_map_element_s *bucket_prev = NULL;
+                while (bucket_next != NULL && bucket_next->key.hash < elm->key.hash) {
+                    bucket_prev = bucket_next;
+                    bucket_next = bucket_next->next;
+                }
+
+                // insert
+                if (bucket_prev == NULL) {
+                    elm->next = new_buckets[new_slot];
+                    new_buckets[new_slot] = elm;
+                } else {
+                    bucket_prev->next = elm;
+                    elm->next = bucket_next;
+                }
+
+                // advance
+                elm = next;
+            }
+        }
+
+        // assign result to the map
+        hash_map->bucket_count = new_bucket_count;
+        cxFree(map->allocator, hash_map->buckets);
+        hash_map->buckets = new_buckets;
+    }
+    return 0;
+}