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 30 #pragma ident "%Z%%M% %I% %E% SMI" 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 */ 165