int hashmap_put(Hashmap *h, const void *key, void *value);
int hashmap_replace(Hashmap *h, const void *key, void *value);
void* hashmap_get(Hashmap *h, const void *key);
+bool hashmap_contains(Hashmap *h, const void *key);
void* hashmap_remove(Hashmap *h, const void *key);
void* hashmap_remove_value(Hashmap *h, const void *key, void *value);
int hashmap_remove_and_put(Hashmap *h, const void *old_key, const void *new_key, void *value);