/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #ifndef _AVL_IMPL_H #define _AVL_IMPL_H /* * This is a private header file. Applications should not directly include * this file. */ #include <sys/types.h> #ifdef __cplusplus extern "C" { #endif /* * generic AVL tree implementation for kernel use * * There are 5 pieces of information stored for each node in an AVL tree * * pointer to less than child * pointer to greater than child * a pointer to the parent of this node * an indication [0/1] of which child I am of my parent * a "balance" (-1, 0, +1) indicating which child tree is taller * * Since they only need 3 bits, the last two fields are packed into the * bottom bits of the parent pointer on 64 bit machines to save on space. */ #ifndef _LP64 struct avl_node { struct avl_node *avl_child[2]; /* left/right children */ struct avl_node *avl_parent; /* this node's parent */ unsigned short avl_child_index; /* my index in parent's avl_child[] */ short avl_balance; /* balance value: -1, 0, +1 */ }; #define AVL_XPARENT(n) ((n)->avl_parent) #define AVL_SETPARENT(n, p) ((n)->avl_parent = (p)) #define AVL_XCHILD(n) ((n)->avl_child_index) #define AVL_SETCHILD(n, c) ((n)->avl_child_index = (unsigned short)(c)) #define AVL_XBALANCE(n) ((n)->avl_balance) #define AVL_SETBALANCE(n, b) ((n)->avl_balance = (short)(b)) #else /* _LP64 */ /* * for 64 bit machines, avl_pcb contains parent pointer, balance and child_index * values packed in the following manner: * * |63 3| 2 |1 0 | * |-------------------------------------|-----------------|-------------| * | avl_parent hi order bits | avl_child_index | avl_balance | * | | | + 1 | * |-------------------------------------|-----------------|-------------| * */ struct avl_node { struct avl_node *avl_child[2]; /* left/right children nodes */ uintptr_t avl_pcb; /* parent, child_index, balance */ }; /* * macros to extract/set fields in avl_pcb * * pointer to the parent of the current node is the high order bits */ #define AVL_XPARENT(n) ((struct avl_node *)((n)->avl_pcb & ~7)) #define AVL_SETPARENT(n, p) \ ((n)->avl_pcb = (((n)->avl_pcb & 7) | (uintptr_t)(p))) /* * index of this node in its parent's avl_child[]: bit #2 */ #define AVL_XCHILD(n) (((n)->avl_pcb >> 2) & 1) #define AVL_SETCHILD(n, c) \ ((n)->avl_pcb = (uintptr_t)(((n)->avl_pcb & ~4) | ((c) << 2))) /* * balance indication for a node, lowest 2 bits. A valid balance is * -1, 0, or +1, and is encoded by adding 1 to the value to get the * unsigned values of 0, 1, 2. */ #define AVL_XBALANCE(n) ((int)(((n)->avl_pcb & 3) - 1)) #define AVL_SETBALANCE(n, b) \ ((n)->avl_pcb = (uintptr_t)((((n)->avl_pcb & ~3) | ((b) + 1)))) #endif /* _LP64 */ /* * switch between a node and data pointer for a given tree * the value of "o" is tree->avl_offset */ #define AVL_NODE2DATA(n, o) ((void *)((uintptr_t)(n) - (o))) #define AVL_DATA2NODE(d, o) ((struct avl_node *)((uintptr_t)(d) + (o))) /* * macros used to create/access an avl_index_t */ #define AVL_INDEX2NODE(x) ((avl_node_t *)((x) & ~1)) #define AVL_INDEX2CHILD(x) ((x) & 1) #define AVL_MKINDEX(n, c) ((avl_index_t)(n) | (c)) /* * The tree structure. The fields avl_root, avl_compar, and avl_offset come * first since they are needed for avl_find(). We want them to fit into * a single 64 byte cache line to make avl_find() as fast as possible. */ struct avl_tree { struct avl_node *avl_root; /* root node in tree */ int (*avl_compar)(const void *, const void *); size_t avl_offset; /* offsetof(type, avl_link_t field) */ ulong_t avl_numnodes; /* number of nodes in the tree */ size_t avl_size; /* sizeof user type struct */ }; /* * This will only by used via AVL_NEXT() or AVL_PREV() */ extern void *avl_walk(struct avl_tree *, void *, int); #ifdef __cplusplus } #endif #endif /* _AVL_IMPL_H */