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  1. /*
  2.  * Copyright (C) 2007 Vojtech Mencl
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericadt
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #ifndef KERN_AVLTREE_H_
  36. #define KERN_AVLTREE_H_
  37.  
  38. #include <arch/types.h>
  39.  
  40. /**
  41.  * Macro for getting a pointer to the structure which contains the avltree
  42.  * structure.
  43.  *
  44.  * @param link Pointer to the avltree structure.
  45.  * @param type Name of the outer structure.
  46.  * @param member Name of avltree attribute in the outer structure.
  47.  */
  48. #define avltree_get_instance(node, type, member) \
  49.     ((type *)(((uint8_t *)(node)) - ((uint8_t *) &(((type *) NULL)->member))))
  50.  
  51. typedef struct avltree_node avltree_node_t;
  52. typedef struct avltree avltree_t;
  53.  
  54. typedef uint64_t avltree_key_t;
  55.  
  56. typedef bool (* avltree_walker_t)(avltree_node_t *, void *);
  57.  
  58. /** AVL tree node structure. */
  59. struct avltree_node
  60. {
  61.     /**
  62.      * Pointer to the left descendant of this node.
  63.      *
  64.      * All keys of nodes in the left subtree are less than the key of this
  65.      * node.
  66.      */
  67.     struct avltree_node *lft;
  68.    
  69.     /**
  70.      * Pointer to the right descendant of this node.
  71.      *
  72.      * All keys of nodes in the right subtree are greater than the key of
  73.      * this node.
  74.      */
  75.     struct avltree_node *rgt;
  76.    
  77.     /** Pointer to the parent node. Root node has NULL parent. */
  78.     struct avltree_node *par;
  79.    
  80.     /** Node's key. */
  81.     avltree_key_t key;
  82.    
  83.     /**
  84.      * Difference between the heights of the left and the right subtree of
  85.      * this node.
  86.      */
  87.     int8_t balance;
  88. };
  89.  
  90. /** AVL tree structure. */
  91. struct avltree
  92. {
  93.     /** AVL root node pointer */
  94.     struct avltree_node *root;
  95.  
  96.     /**
  97.      * Base of the tree is a value that is smaller or equal than every value
  98.      * in the tree (valid for positive keys otherwise ignore this atribute).
  99.      *  
  100.      * The base is added to the current key when a new node is inserted into
  101.      * the tree. The base is changed to the key of the node which is deleted
  102.      * with avltree_delete_min().
  103.      */
  104.     avltree_key_t base;
  105. };
  106.  
  107.  
  108. /** Create empty AVL tree.
  109.  *
  110.  * @param t AVL tree.
  111.  */
  112. static inline void avltree_create(avltree_t *t)
  113. {
  114.     t->root = NULL;
  115.     t->base = 0;
  116. }
  117.  
  118. /** Initialize node.
  119.  *
  120.  * @param node Node which is initialized.
  121.  */
  122. static inline void avltree_node_initialize(avltree_node_t *node)
  123. {
  124.     node->key = 0;
  125.     node->lft = NULL;
  126.     node->rgt = NULL;
  127.     node->par = NULL;
  128.     node->balance = 0;
  129. }
  130.  
  131. extern avltree_node_t *avltree_find_min(avltree_t *t);
  132. extern avltree_node_t *avltree_search(avltree_t *t, avltree_key_t key);
  133. extern void avltree_insert(avltree_t *t, avltree_node_t *newnode);
  134. extern void avltree_delete(avltree_t *t, avltree_node_t *node);
  135. extern bool avltree_delete_min(avltree_t *t);
  136. extern void avltree_walk(avltree_t *t, avltree_walker_t walker, void *arg);
  137.  
  138. #endif
  139.  
  140. /** @}
  141.  */
  142.