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Diffstat (limited to 'avl_data.h')
| -rw-r--r-- | avl_data.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/avl_data.h b/avl_data.h new file mode 100644 index 0000000..17ec7a3 --- /dev/null +++ b/avl_data.h @@ -0,0 +1,173 @@ +/* + * 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. + */ +/* + * Portions copyright 2013 Igor Pashev <pashev.igor@gmail.com> + */ + +#ifndef _LIBSUNAVL_AVL_DATA_H +#define _LIBSUNAVL_AVL_DATA_H + +#include <stddef.h> +#include <inttypes.h> + +#ifdef __cplusplus +extern "C" { +#endif + + +/* + * generic AVL tree implementation + * + * 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) */ + size_t avl_numnodes; /* number of nodes in the tree */ + size_t avl_size; /* sizeof user type struct */ +}; + +/* + * Type used for the root of the AVL tree. + */ +typedef struct avl_tree avl_tree_t; + +/* + * The data nodes in the AVL tree must have a field of this type. + */ +typedef struct avl_node avl_node_t; + +/* + * An opaque type used to locate a position in the tree where a node + * would be inserted. + */ +typedef uintptr_t avl_index_t; + + +#ifdef __cplusplus +} +#endif + +#endif /* _LIBSUNAVL_AVL_DATA_H */ + |