1 /* "Rotating trees" (Armin Rigo)
2  *
3  * Google "splay trees" for the general idea.
4  *
5  * It's a dict-like data structure that works best when accesses are not
6  * random, but follow a strong pattern.  The one implemented here is for
7  * access patterns where the same small set of keys is looked up over
8  * and over again, and this set of keys evolves slowly over time.
9  */
10 
11 #include <stdlib.h>
12 
13 #define EMPTY_ROTATING_TREE       ((rotating_node_t *)NULL)
14 
15 typedef struct rotating_node_s rotating_node_t;
16 typedef int (*rotating_tree_enum_fn) (rotating_node_t *node, void *arg);
17 
18 struct rotating_node_s {
19 	void *key;
20 	rotating_node_t *left;
21 	rotating_node_t *right;
22 };
23 
24 void RotatingTree_Add(rotating_node_t **root, rotating_node_t *node);
25 rotating_node_t* RotatingTree_Get(rotating_node_t **root, void *key);
26 int RotatingTree_Enum(rotating_node_t *root, rotating_tree_enum_fn enumfn,
27 		      void *arg);
28