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1 | /* |
2 | * CDDL HEADER START | |
3 | * | |
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 | |
7 | * with the License. | |
8 | * | |
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. | |
13 | * | |
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] | |
19 | * | |
20 | * CDDL HEADER END | |
21 | */ | |
22 | /* | |
23 | * Copyright 2004 Sun Microsystems, Inc. All rights reserved. | |
24 | * Use is subject to license terms. | |
25 | */ | |
26 | ||
27 | #ifndef _AVL_IMPL_H | |
28 | #define _AVL_IMPL_H | |
29 | ||
b128c09f | 30 | #pragma ident "%Z%%M% %I% %E% SMI" |
34dc7c2f BB |
31 | |
32 | /* | |
33 | * This is a private header file. Applications should not directly include | |
34 | * this file. | |
35 | */ | |
36 | ||
37 | #include <sys/types.h> | |
38 | ||
39 | #ifdef __cplusplus | |
40 | extern "C" { | |
41 | #endif | |
42 | ||
43 | ||
44 | /* | |
45 | * generic AVL tree implementation for kernel use | |
46 | * | |
47 | * There are 5 pieces of information stored for each node in an AVL tree | |
48 | * | |
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 | |
54 | * | |
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. | |
57 | */ | |
58 | ||
59 | #ifndef _LP64 | |
60 | ||
61 | struct avl_node { | |
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 */ | |
66 | }; | |
67 | ||
68 | #define AVL_XPARENT(n) ((n)->avl_parent) | |
69 | #define AVL_SETPARENT(n, p) ((n)->avl_parent = (p)) | |
70 | ||
71 | #define AVL_XCHILD(n) ((n)->avl_child_index) | |
72 | #define AVL_SETCHILD(n, c) ((n)->avl_child_index = (unsigned short)(c)) | |
73 | ||
74 | #define AVL_XBALANCE(n) ((n)->avl_balance) | |
75 | #define AVL_SETBALANCE(n, b) ((n)->avl_balance = (short)(b)) | |
76 | ||
77 | #else /* _LP64 */ | |
78 | ||
79 | /* | |
80 | * for 64 bit machines, avl_pcb contains parent pointer, balance and child_index | |
81 | * values packed in the following manner: | |
82 | * | |
83 | * |63 3| 2 |1 0 | | |
84 | * |-------------------------------------|-----------------|-------------| | |
85 | * | avl_parent hi order bits | avl_child_index | avl_balance | | |
86 | * | | | + 1 | | |
87 | * |-------------------------------------|-----------------|-------------| | |
88 | * | |
89 | */ | |
90 | struct avl_node { | |
91 | struct avl_node *avl_child[2]; /* left/right children nodes */ | |
92 | uintptr_t avl_pcb; /* parent, child_index, balance */ | |
93 | }; | |
94 | ||
95 | /* | |
96 | * macros to extract/set fields in avl_pcb | |
97 | * | |
98 | * pointer to the parent of the current node is the high order bits | |
99 | */ | |
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))) | |
103 | ||
104 | /* | |
105 | * index of this node in its parent's avl_child[]: bit #2 | |
106 | */ | |
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))) | |
110 | ||
111 | /* | |
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. | |
115 | */ | |
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)))) | |
119 | ||
120 | #endif /* _LP64 */ | |
121 | ||
122 | ||
123 | ||
124 | /* | |
125 | * switch between a node and data pointer for a given tree | |
126 | * the value of "o" is tree->avl_offset | |
127 | */ | |
128 | #define AVL_NODE2DATA(n, o) ((void *)((uintptr_t)(n) - (o))) | |
129 | #define AVL_DATA2NODE(d, o) ((struct avl_node *)((uintptr_t)(d) + (o))) | |
130 | ||
131 | ||
132 | ||
133 | /* | |
134 | * macros used to create/access an avl_index_t | |
135 | */ | |
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)) | |
139 | ||
140 | ||
141 | /* | |
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. | |
145 | */ | |
146 | struct avl_tree { | |
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 */ | |
152 | }; | |
153 | ||
154 | ||
155 | /* | |
156 | * This will only by used via AVL_NEXT() or AVL_PREV() | |
157 | */ | |
158 | extern void *avl_walk(struct avl_tree *, void *, int); | |
159 | ||
160 | #ifdef __cplusplus | |
161 | } | |
162 | #endif | |
163 | ||
164 | #endif /* _AVL_IMPL_H */ |