4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
30 #pragma ident "%Z%%M% %I% %E% SMI"
33 * This is a private header file. Applications should not directly include
37 #include <sys/types.h>
45 * generic AVL tree implementation for kernel use
47 * There are 5 pieces of information stored for each node in an AVL tree
49 * pointer to less than child
50 * pointer to greater than child
51 * a pointer to the parent of this node
52 * an indication [0/1] of which child I am of my parent
53 * a "balance" (-1, 0, +1) indicating which child tree is taller
55 * Since they only need 3 bits, the last two fields are packed into the
56 * bottom bits of the parent pointer on 64 bit machines to save on space.
62 struct avl_node
*avl_child
[2]; /* left/right children */
63 struct avl_node
*avl_parent
; /* this node's parent */
64 unsigned short avl_child_index
; /* my index in parent's avl_child[] */
65 short avl_balance
; /* balance value: -1, 0, +1 */
68 #define AVL_XPARENT(n) ((n)->avl_parent)
69 #define AVL_SETPARENT(n, p) ((n)->avl_parent = (p))
71 #define AVL_XCHILD(n) ((n)->avl_child_index)
72 #define AVL_SETCHILD(n, c) ((n)->avl_child_index = (unsigned short)(c))
74 #define AVL_XBALANCE(n) ((n)->avl_balance)
75 #define AVL_SETBALANCE(n, b) ((n)->avl_balance = (short)(b))
80 * for 64 bit machines, avl_pcb contains parent pointer, balance and child_index
81 * values packed in the following manner:
84 * |-------------------------------------|-----------------|-------------|
85 * | avl_parent hi order bits | avl_child_index | avl_balance |
87 * |-------------------------------------|-----------------|-------------|
91 struct avl_node
*avl_child
[2]; /* left/right children nodes */
92 uintptr_t avl_pcb
; /* parent, child_index, balance */
96 * macros to extract/set fields in avl_pcb
98 * pointer to the parent of the current node is the high order bits
100 #define AVL_XPARENT(n) ((struct avl_node *)((n)->avl_pcb & ~7))
101 #define AVL_SETPARENT(n, p) \
102 ((n)->avl_pcb = (((n)->avl_pcb & 7) | (uintptr_t)(p)))
105 * index of this node in its parent's avl_child[]: bit #2
107 #define AVL_XCHILD(n) (((n)->avl_pcb >> 2) & 1)
108 #define AVL_SETCHILD(n, c) \
109 ((n)->avl_pcb = (uintptr_t)(((n)->avl_pcb & ~4) | ((c) << 2)))
112 * balance indication for a node, lowest 2 bits. A valid balance is
113 * -1, 0, or +1, and is encoded by adding 1 to the value to get the
114 * unsigned values of 0, 1, 2.
116 #define AVL_XBALANCE(n) ((int)(((n)->avl_pcb & 3) - 1))
117 #define AVL_SETBALANCE(n, b) \
118 ((n)->avl_pcb = (uintptr_t)((((n)->avl_pcb & ~3) | ((b) + 1))))
125 * switch between a node and data pointer for a given tree
126 * the value of "o" is tree->avl_offset
128 #define AVL_NODE2DATA(n, o) ((void *)((uintptr_t)(n) - (o)))
129 #define AVL_DATA2NODE(d, o) ((struct avl_node *)((uintptr_t)(d) + (o)))
134 * macros used to create/access an avl_index_t
136 #define AVL_INDEX2NODE(x) ((avl_node_t *)((x) & ~1))
137 #define AVL_INDEX2CHILD(x) ((x) & 1)
138 #define AVL_MKINDEX(n, c) ((avl_index_t)(n) | (c))
142 * The tree structure. The fields avl_root, avl_compar, and avl_offset come
143 * first since they are needed for avl_find(). We want them to fit into
144 * a single 64 byte cache line to make avl_find() as fast as possible.
147 struct avl_node
*avl_root
; /* root node in tree */
148 int (*avl_compar
)(const void *, const void *);
149 size_t avl_offset
; /* offsetof(type, avl_link_t field) */
150 ulong_t avl_numnodes
; /* number of nodes in the tree */
151 size_t avl_size
; /* sizeof user type struct */
156 * This will only by used via AVL_NEXT() or AVL_PREV()
158 extern void *avl_walk(struct avl_tree
*, void *, int);
164 #endif /* _AVL_IMPL_H */