/*
* ANSI C Library for maintainance of AVL Balanced Trees
*
* ref.:
* G. M. Adelson-Velskij & E. M. Landis
* Doklady Akad. Nauk SSSR 146 (1962), 263-266
*
* see also:
* D. E. Knuth: The Art of Computer Programming Vol.3 (Sorting and Searching)
*
* (C) 2000 Daniel Nagy, Budapest University of Technology and Economics
* Released under GNU General Public License (GPL) version 2
*
*/
#ifndef _AVL_H
#define _AVL_H 1
/* Data structures */
/* One element of the AVL tree */
typedef struct avl
{
struct avl* left;
struct avl* right;
signed char balance;
} avl;
/* An AVL tree */
typedef struct avl_tree
{
avl* root;
int(*compar)(void* a,void* b);
} avl_tree;
/* Public methods */
/* Insert element a into the AVL tree t
* returns 1 if the depth of the tree has grown
* Warning: do not insert elements already present
*/
int avl_insert(avl_tree* t,avl* a);
/* Remove an element a from the AVL tree t
* returns -1 if the depth of the tree has shrunk
* Warning: if the element is not present in the tree,
* returns 0 as if it had been removed succesfully.
*/
int avl_remove(avl_tree* t, avl* a);
/* Remove the root of the AVL tree t
* Warning: dumps core if t is empty
*/
int avl_removeroot(avl_tree* t);
/* Iterate through elements in t from a range between a and b (inclusive)
* for each element calls iter(a) until it returns 0
* returns the last value returned by iterator or 0 if there were no calls
* Warning: a<=b must hold
*/
int avl_range(avl_tree* t,avl* a,avl* b,int(*iter)(avl* a));
/* Iterate through elements in t equal to a
* for each element calls iter(a) until it returns 0
* returns the last value returned by iterator or 0 if there were no calls
*/
int avl_search(avl_tree* t, avl* a,int(*iter)(avl* a));
#endif /* avl.h */