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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.  
  36. #ifndef KERN_AVLTREE_H_
  37. #define KERN_AVLTREE_H_
  38.  
  39. #include <arch/types.h>
  40.  
  41. /**
  42.  * Macro for getting a pointer to the structure which contains the avltree
  43.  * structure.
  44.  *
  45.  * @param link Pointer to the avltree structure.
  46.  * @param type Name of the outer structure.
  47.  * @param member Name of avltree attribute in the outer structure.
  48.  */
  49. #define avltree_get_instance(link, type, member) \
  50.     ((type *)(((uint8_t *)(link)) - ((uint8_t *) &(((type *) NULL)->member))))
  51.  
  52.  
  53. typedef struct avltree_node avltree_node_t;
  54. typedef struct avltree avltree_t;
  55.  
  56.  
  57. /** AVL tree node structure. */
  58. struct avltree_node
  59. {
  60.     /**
  61.      * Pointer to the left descendant of this node.
  62.      *
  63.      * All keys of nodes in the left subtree are less than the key of this
  64.      * node.
  65.      */
  66.     struct avltree_node *lft;
  67.    
  68.     /**
  69.      * Pointer to the right descendant of this node.
  70.      *
  71.      * All keys of nodes in the right subtree are greater than the key of
  72.      * this node.
  73.      */
  74.     struct avltree_node *rgt;
  75.    
  76.     /** Pointer to the parent node. Root node has NULL parent. */
  77.     struct avltree_node *par;
  78.    
  79.     /** Node's key. */
  80.     uint64_t key;
  81.    
  82.     /**
  83.      * Difference between the heights of the left and the right subtree of
  84.      * this node.
  85.      */
  86.     int8_t balance;
  87. };
  88.  
  89. /** AVL tree structure. */
  90. struct avltree
  91. {
  92.     /** AVL root node pointer */
  93.     struct avltree_node *root;
  94.  
  95.     /**
  96.      * Base of the tree is a value that is smaller or equal than every value
  97.      * in the tree (valid for positive keys otherwise ignore this atribute).
  98.      *  
  99.      * The base is added to the current key when a new node is inserted into
  100.      * the tree. The base is changed to the key of the node which is deleted
  101.      * with avltree_delete_min().
  102.      */
  103.     uint64_t base;
  104. };
  105.  
  106.  
  107. /** Create empty AVL tree.
  108.  *
  109.  * @param t AVL tree.
  110.  */
  111. static inline void avltree_create (avltree_t *t)
  112. {
  113.     t->root = NULL;
  114.     t->base = 0;
  115. }
  116.  
  117. /** Initialize node.
  118.  *
  119.  * @param node Node which is initialized.
  120.  */
  121. static inline void avltree_node_initialize(avltree_node_t *node)
  122. {
  123.     node->key = 0;
  124.     node->lft = NULL;
  125.     node->rgt = NULL;
  126.     node->par = NULL;
  127.     node->balance = 0;
  128. }
  129.  
  130. extern avltree_node_t *avltree_find_min(avltree_t *t);
  131. extern avltree_node_t *avltree_search(avltree_t *t, uint64_t key);
  132. extern void avltree_insert(avltree_t *t, avltree_node_t *newnode);
  133. extern void avltree_delete(avltree_t *t, avltree_node_t *node);
  134. extern bool avltree_delete_min(avltree_t *t);
  135.  
  136. #endif
  137.  
  138. /** @}
  139.  */
  140.