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9530eb64e0
Sponsored-by: https://despairlabs.com/sponsor/ Signed-off-by: Rob Norris <robn@despairlabs.com> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
168 lines
4.9 KiB
C
168 lines
4.9 KiB
C
// SPDX-License-Identifier: CDDL-1.0
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/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or https://opensource.org/licenses/CDDL-1.0.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#ifndef _AVL_IMPL_H
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#define _AVL_IMPL_H extern __attribute__((visibility("default")))
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/*
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* This is a private header file. Applications should not directly include
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* this file.
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*/
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#include <sys/types.h>
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#include <sys/sysmacros.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* generic AVL tree implementation for kernel use
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*
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* There are 5 pieces of information stored for each node in an AVL tree
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*
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* pointer to less than child
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* pointer to greater than child
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* a pointer to the parent of this node
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* an indication [0/1] of which child I am of my parent
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* a "balance" (-1, 0, +1) indicating which child tree is taller
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*
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* Since they only need 3 bits, the last two fields are packed into the
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* bottom bits of the parent pointer on 64 bit machines to save on space.
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*/
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#ifndef _LP64
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struct avl_node {
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struct avl_node *avl_child[2]; /* left/right children */
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struct avl_node *avl_parent; /* this node's parent */
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unsigned short avl_child_index; /* my index in parent's avl_child[] */
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short avl_balance; /* balance value: -1, 0, +1 */
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};
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#define AVL_XPARENT(n) ((n)->avl_parent)
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#define AVL_SETPARENT(n, p) ((n)->avl_parent = (p))
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#define AVL_XCHILD(n) ((n)->avl_child_index)
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#define AVL_SETCHILD(n, c) ((n)->avl_child_index = (unsigned short)(c))
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#define AVL_XBALANCE(n) ((n)->avl_balance)
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#define AVL_SETBALANCE(n, b) ((n)->avl_balance = (short)(b))
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#else /* _LP64 */
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/*
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* for 64 bit machines, avl_pcb contains parent pointer, balance and child_index
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* values packed in the following manner:
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*
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* |63 3| 2 |1 0 |
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* |-------------------------------------|-----------------|-------------|
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* | avl_parent hi order bits | avl_child_index | avl_balance |
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* | | | + 1 |
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* |-------------------------------------|-----------------|-------------|
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*
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*/
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struct avl_node {
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struct avl_node *avl_child[2]; /* left/right children nodes */
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uintptr_t avl_pcb; /* parent, child_index, balance */
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};
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/*
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* macros to extract/set fields in avl_pcb
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*
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* pointer to the parent of the current node is the high order bits
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*/
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#define AVL_XPARENT(n) ((struct avl_node *)((n)->avl_pcb & ~7))
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#define AVL_SETPARENT(n, p) \
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((n)->avl_pcb = (((n)->avl_pcb & 7) | (uintptr_t)(p)))
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/*
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* index of this node in its parent's avl_child[]: bit #2
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*/
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#define AVL_XCHILD(n) (((n)->avl_pcb >> 2) & 1)
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#define AVL_SETCHILD(n, c) \
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((n)->avl_pcb = (uintptr_t)(((n)->avl_pcb & ~4) | ((c) << 2)))
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/*
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* balance indication for a node, lowest 2 bits. A valid balance is
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* -1, 0, or +1, and is encoded by adding 1 to the value to get the
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* unsigned values of 0, 1, 2.
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*/
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#define AVL_XBALANCE(n) ((int)(((n)->avl_pcb & 3) - 1))
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#define AVL_SETBALANCE(n, b) \
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((n)->avl_pcb = (uintptr_t)((((n)->avl_pcb & ~3) | ((b) + 1))))
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#endif /* _LP64 */
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/*
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* switch between a node and data pointer for a given tree
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* the value of "o" is tree->avl_offset
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*/
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#define AVL_NODE2DATA(n, o) ((void *)((uintptr_t)(n) - (o)))
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#define AVL_DATA2NODE(d, o) ((struct avl_node *)((uintptr_t)(d) + (o)))
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/*
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* macros used to create/access an avl_index_t
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*/
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#define AVL_INDEX2NODE(x) ((avl_node_t *)((x) & ~1))
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#define AVL_INDEX2CHILD(x) ((x) & 1)
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#define AVL_MKINDEX(n, c) ((avl_index_t)(n) | (c))
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/*
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* The tree structure. The fields avl_root, avl_compar, and avl_offset come
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* first since they are needed for avl_find(). We want them to fit into
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* a single 64 byte cache line to make avl_find() as fast as possible.
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*/
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struct avl_tree {
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struct avl_node *avl_root; /* root node in tree */
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int (*avl_compar)(const void *, const void *);
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size_t avl_offset; /* offsetof(type, avl_link_t field) */
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ulong_t avl_numnodes; /* number of nodes in the tree */
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#ifndef _KERNEL
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size_t avl_pad; /* For backwards ABI compatibility. */
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#endif
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};
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/*
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* This will only by used via AVL_NEXT() or AVL_PREV()
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*/
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_AVL_IMPL_H void *avl_walk(struct avl_tree *, void *, int);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _AVL_IMPL_H */
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