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);