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 https://opensource.org/licenses/CDDL-1.0. 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 extern __attribute__((visibility("default"))) 29 30 31 /* 32 * This is a private header file. Applications should not directly include 33 * this file. 34 */ 35 36 #include <sys/types.h> 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 43 /* 44 * generic AVL tree implementation for kernel use 45 * 46 * There are 5 pieces of information stored for each node in an AVL tree 47 * 48 * pointer to less than child 49 * pointer to greater than child 50 * a pointer to the parent of this node 51 * an indication [0/1] of which child I am of my parent 52 * a "balance" (-1, 0, +1) indicating which child tree is taller 53 * 54 * Since they only need 3 bits, the last two fields are packed into the 55 * bottom bits of the parent pointer on 64 bit machines to save on space. 56 */ 57 58 #ifndef _LP64 59 60 struct avl_node { 61 struct avl_node *avl_child[2]; /* left/right children */ 62 struct avl_node *avl_parent; /* this node's parent */ 63 unsigned short avl_child_index; /* my index in parent's avl_child[] */ 64 short avl_balance; /* balance value: -1, 0, +1 */ 65 }; 66 67 #define AVL_XPARENT(n) ((n)->avl_parent) 68 #define AVL_SETPARENT(n, p) ((n)->avl_parent = (p)) 69 70 #define AVL_XCHILD(n) ((n)->avl_child_index) 71 #define AVL_SETCHILD(n, c) ((n)->avl_child_index = (unsigned short)(c)) 72 73 #define AVL_XBALANCE(n) ((n)->avl_balance) 74 #define AVL_SETBALANCE(n, b) ((n)->avl_balance = (short)(b)) 75 76 #else /* _LP64 */ 77 78 /* 79 * for 64 bit machines, avl_pcb contains parent pointer, balance and child_index 80 * values packed in the following manner: 81 * 82 * |63 3| 2 |1 0 | 83 * |-------------------------------------|-----------------|-------------| 84 * | avl_parent hi order bits | avl_child_index | avl_balance | 85 * | | | + 1 | 86 * |-------------------------------------|-----------------|-------------| 87 * 88 */ 89 struct avl_node { 90 struct avl_node *avl_child[2]; /* left/right children nodes */ 91 uintptr_t avl_pcb; /* parent, child_index, balance */ 92 }; 93 94 /* 95 * macros to extract/set fields in avl_pcb 96 * 97 * pointer to the parent of the current node is the high order bits 98 */ 99 #define AVL_XPARENT(n) ((struct avl_node *)((n)->avl_pcb & ~7)) 100 #define AVL_SETPARENT(n, p) \ 101 ((n)->avl_pcb = (((n)->avl_pcb & 7) | (uintptr_t)(p))) 102 103 /* 104 * index of this node in its parent's avl_child[]: bit #2 105 */ 106 #define AVL_XCHILD(n) (((n)->avl_pcb >> 2) & 1) 107 #define AVL_SETCHILD(n, c) \ 108 ((n)->avl_pcb = (uintptr_t)(((n)->avl_pcb & ~4) | ((c) << 2))) 109 110 /* 111 * balance indication for a node, lowest 2 bits. A valid balance is 112 * -1, 0, or +1, and is encoded by adding 1 to the value to get the 113 * unsigned values of 0, 1, 2. 114 */ 115 #define AVL_XBALANCE(n) ((int)(((n)->avl_pcb & 3) - 1)) 116 #define AVL_SETBALANCE(n, b) \ 117 ((n)->avl_pcb = (uintptr_t)((((n)->avl_pcb & ~3) | ((b) + 1)))) 118 119 #endif /* _LP64 */ 120 121 122 123 /* 124 * switch between a node and data pointer for a given tree 125 * the value of "o" is tree->avl_offset 126 */ 127 #define AVL_NODE2DATA(n, o) ((void *)((uintptr_t)(n) - (o))) 128 #define AVL_DATA2NODE(d, o) ((struct avl_node *)((uintptr_t)(d) + (o))) 129 130 131 132 /* 133 * macros used to create/access an avl_index_t 134 */ 135 #define AVL_INDEX2NODE(x) ((avl_node_t *)((x) & ~1)) 136 #define AVL_INDEX2CHILD(x) ((x) & 1) 137 #define AVL_MKINDEX(n, c) ((avl_index_t)(n) | (c)) 138 139 140 /* 141 * The tree structure. The fields avl_root, avl_compar, and avl_offset come 142 * first since they are needed for avl_find(). We want them to fit into 143 * a single 64 byte cache line to make avl_find() as fast as possible. 144 */ 145 struct avl_tree { 146 struct avl_node *avl_root; /* root node in tree */ 147 int (*avl_compar)(const void *, const void *); 148 size_t avl_offset; /* offsetof(type, avl_link_t field) */ 149 ulong_t avl_numnodes; /* number of nodes in the tree */ 150 #ifndef _KERNEL 151 size_t avl_pad; /* For backwards ABI compatibility. */ 152 #endif 153 }; 154 155 156 /* 157 * This will only by used via AVL_NEXT() or AVL_PREV() 158 */ 159 _AVL_IMPL_H void *avl_walk(struct avl_tree *, void *, int); 160 161 #ifdef __cplusplus 162 } 163 #endif 164 165 #endif /* _AVL_IMPL_H */ 166