#define DOES_NOT_EXIST 0
+#define EXPECT_DOES_NOT_EXIST ( 0)
+#define EXPECT_EXISTS (-1)
+#define EXPECT_WHATEVER (-2)
+
+typedef struct hti *hashtable_t;
+hashtable_t *ht_alloc (void);
+void ht_free (hashtable_t *ht);
+
+uint64_t ht_compare_and_set (hashtable_t *ht, const char *key, uint32_t key_len, uint64_t expected_val, uint64_t val);
+uint64_t ht_get (hashtable_t *ht, const char *key, uint32_t len);
+uint64_t ht_remove (hashtable_t *ht, const char *key, uint32_t len);
+uint64_t ht_count (hashtable_t *ht);
+
+typedef struct ll list_t;
+list_t * ll_alloc (void);
+
+uint64_t ll_lookup (list_t *ll, const void *key_data, uint32_t key_len);
+uint64_t ll_add (list_t *ll, const void *key_data, uint32_t key_len, uint64_t value);
+uint64_t ll_remove (list_t *ll, const void *key_data, uint32_t key_len);
+void ll_print (list_t *ll);
+
+typedef struct sl skiplist_t;
+skiplist_t * sl_alloc (void);
+
+uint64_t sl_lookup (skiplist_t *sl, const void *key_data, uint32_t key_len);
+uint64_t sl_add (skiplist_t *sl, const void *key_data, uint32_t key_len, uint64_t value);
+uint64_t sl_remove (skiplist_t *sl, const void *key_data, uint32_t key_len);
+void sl_print (skiplist_t *sl);
+
#endif//STRUCT_H