-map_t * map_alloc (map_type_t map_type, const datatype_t *key_type);
-uint64_t map_get (map_t *map, void *key);
-uint64_t map_set (map_t *map, void *key, uint64_t new_val);
-uint64_t map_add (map_t *map, void *key, uint64_t new_val);
-uint64_t map_cas (map_t *map, void *key, uint64_t expected_val, uint64_t new_val);
-uint64_t map_replace(map_t *map, void *key, uint64_t new_val);
-uint64_t map_remove (map_t *map, void *key);
-uint64_t map_count (map_t *map);
-void map_print (map_t *map);
-void map_free (map_t *map);
+map_iter_t * map_iter_begin (map_t *map, map_key_t key);
+map_val_t map_iter_next (map_iter_t *iter, map_key_t *key);
+void map_iter_free (map_iter_t *iter);
+
+/////////////////////////////////////////////////////////////////////////////////////
+
+#define CAS_EXPECT_DOES_NOT_EXIST ( 0)
+#define CAS_EXPECT_EXISTS (-1)
+#define CAS_EXPECT_WHATEVER (-2)
+
+typedef void * (*map_alloc_t) (const datatype_t *);
+typedef map_val_t (*map_cas_t) (void *, map_key_t , map_val_t, map_val_t);
+typedef map_val_t (*map_get_t) (void *, map_key_t );
+typedef map_val_t (*map_remove_t) (void *, map_key_t );
+typedef size_t (*map_count_t) (void *);
+typedef void (*map_print_t) (void *);
+typedef void (*map_free_t) (void *);
+
+typedef map_iter_t * (*map_iter_begin_t) (void *, map_key_t);
+typedef map_val_t (*map_iter_next_t) (map_iter_t *, map_key_t *);
+typedef void (*map_iter_free_t) (map_iter_t *);
+
+struct map_impl {
+ map_alloc_t alloc;
+ map_cas_t cas;
+ map_get_t get;
+ map_remove_t remove;
+ map_count_t count;
+ map_print_t print;
+ map_free_t free_;
+
+ map_iter_begin_t iter_begin;
+ map_iter_next_t iter_next;
+ map_iter_free_t iter_free;
+};