1/* $NetBSD: rbtree.h,v 1.12 2024/05/12 10:34:56 rillig Exp $ */
2
3/*-
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas <matt@3am-software.com>.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _SYS_RBTREE_H_
33#define _SYS_RBTREE_H_
34
35#include <sys/types.h>
36#include <sys/queue.h>
37#include <sys/endian.h>
38
39#if !defined(_KERNEL) && !defined(_STANDALONE) && defined(RBDEBUG)
40#include <stdbool.h>
41#endif
42
43__BEGIN_DECLS
44
45typedef struct rb_node {
46 struct rb_node *rb_nodes[2];
47#define RB_DIR_LEFT 0
48#define RB_DIR_RIGHT 1
49#define RB_DIR_OTHER 1
50#define rb_left rb_nodes[RB_DIR_LEFT]
51#define rb_right rb_nodes[RB_DIR_RIGHT]
52
53 /*
54 * rb_info contains the two flags and the parent back pointer.
55 * We put the two flags in the low two bits since we know that
56 * rb_node will have an alignment of 4 or 8 bytes.
57 */
58 uintptr_t rb_info;
59#define RB_FLAG_POSITION (uintptr_t)0x2
60#define RB_FLAG_RED (uintptr_t)0x1
61#define RB_FLAG_MASK (RB_FLAG_POSITION|RB_FLAG_RED)
62#define RB_FATHER(rb) \
63 ((struct rb_node *)((rb)->rb_info & ~RB_FLAG_MASK))
64#define RB_SET_FATHER(rb, father) \
65 ((void)((rb)->rb_info = (uintptr_t)(father)|((rb)->rb_info & RB_FLAG_MASK)))
66
67#define RB_SENTINEL_P(rb) ((rb) == NULL)
68#define RB_LEFT_SENTINEL_P(rb) RB_SENTINEL_P((rb)->rb_left)
69#define RB_RIGHT_SENTINEL_P(rb) RB_SENTINEL_P((rb)->rb_right)
70#define RB_FATHER_SENTINEL_P(rb) RB_SENTINEL_P(RB_FATHER((rb)))
71#define RB_CHILDLESS_P(rb) \
72 (RB_SENTINEL_P(rb) || (RB_LEFT_SENTINEL_P(rb) && RB_RIGHT_SENTINEL_P(rb)))
73#define RB_TWOCHILDREN_P(rb) \
74 (!RB_SENTINEL_P(rb) && !RB_LEFT_SENTINEL_P(rb) && !RB_RIGHT_SENTINEL_P(rb))
75
76#define RB_POSITION(rb) \
77 (((rb)->rb_info & RB_FLAG_POSITION) ? RB_DIR_RIGHT : RB_DIR_LEFT)
78#define RB_RIGHT_P(rb) (RB_POSITION(rb) == RB_DIR_RIGHT)
79#define RB_LEFT_P(rb) (RB_POSITION(rb) == RB_DIR_LEFT)
80#define RB_RED_P(rb) (!RB_SENTINEL_P(rb) && ((rb)->rb_info & RB_FLAG_RED) != 0)
81#define RB_BLACK_P(rb) (RB_SENTINEL_P(rb) || ((rb)->rb_info & RB_FLAG_RED) == 0)
82#define RB_MARK_RED(rb) ((void)((rb)->rb_info |= RB_FLAG_RED))
83#define RB_MARK_BLACK(rb) ((void)((rb)->rb_info &= ~RB_FLAG_RED))
84#define RB_INVERT_COLOR(rb) ((void)((rb)->rb_info ^= RB_FLAG_RED))
85#define RB_ROOT_P(rbt, rb) ((rbt)->rbt_root == (rb))
86#define RB_SET_POSITION(rb, position) \
87 ((void)((position) ? ((rb)->rb_info |= RB_FLAG_POSITION) : \
88 ((rb)->rb_info &= ~RB_FLAG_POSITION)))
89#define RB_ZERO_PROPERTIES(rb) ((void)((rb)->rb_info &= ~RB_FLAG_MASK))
90#define RB_COPY_PROPERTIES(dst, src) \
91 ((void)((dst)->rb_info ^= ((dst)->rb_info ^ (src)->rb_info) & RB_FLAG_MASK))
92#define RB_SWAP_PROPERTIES(a, b) do { \
93 uintptr_t xorinfo = ((a)->rb_info ^ (b)->rb_info) & RB_FLAG_MASK; \
94 (a)->rb_info ^= xorinfo; \
95 (b)->rb_info ^= xorinfo; \
96 } while (0)
97#ifdef RBDEBUG
98 TAILQ_ENTRY(rb_node) rb_link;
99#endif
100} rb_node_t;
101
102#define RB_TREE_MIN(T) rb_tree_iterate((T), NULL, RB_DIR_LEFT)
103#define RB_TREE_MAX(T) rb_tree_iterate((T), NULL, RB_DIR_RIGHT)
104#define RB_TREE_NEXT(T, N) rb_tree_iterate((T), (N), RB_DIR_RIGHT)
105#define RB_TREE_PREV(T, N) rb_tree_iterate((T), (N), RB_DIR_LEFT)
106#define RB_TREE_FOREACH(N, T) \
107 for ((N) = RB_TREE_MIN(T); (N); (N) = RB_TREE_NEXT((T), (N)))
108#define RB_TREE_FOREACH_REVERSE(N, T) \
109 for ((N) = RB_TREE_MAX(T); (N); (N) = RB_TREE_PREV((T), (N)))
110#define RB_TREE_FOREACH_SAFE(N, T, S) \
111 for ((N) = RB_TREE_MIN(T); \
112 (N) && ((S) = RB_TREE_NEXT((T), (N)), 1); \
113 (N) = (S))
114#define RB_TREE_FOREACH_REVERSE_SAFE(N, T, S) \
115 for ((N) = RB_TREE_MAX(T); \
116 (N) && ((S) = RB_TREE_PREV((T), (N)), 1); \
117 (N) = (S))
118
119#ifdef RBDEBUG
120TAILQ_HEAD(rb_node_qh, rb_node);
121
122#define RB_TAILQ_REMOVE(a, b, c) TAILQ_REMOVE(a, b, c)
123#define RB_TAILQ_INIT(a) TAILQ_INIT(a)
124#define RB_TAILQ_INSERT_HEAD(a, b, c) TAILQ_INSERT_HEAD(a, b, c)
125#define RB_TAILQ_INSERT_BEFORE(a, b, c) TAILQ_INSERT_BEFORE(a, b, c)
126#define RB_TAILQ_INSERT_AFTER(a, b, c, d) TAILQ_INSERT_AFTER(a, b, c, d)
127
128#define RBDEBUG_TREE_INITIALIZER(t) \
129 .rbt_nodes = TAILQ_HEAD_INITIALIZER((t).rbt_nodes),
130#else
131#define RB_TAILQ_REMOVE(a, b, c) do { } while (0)
132#define RB_TAILQ_INIT(a) do { } while (0)
133#define RB_TAILQ_INSERT_HEAD(a, b, c) do { } while (0)
134#define RB_TAILQ_INSERT_BEFORE(a, b, c) do { } while (0)
135#define RB_TAILQ_INSERT_AFTER(a, b, c, d) do { } while (0)
136
137#define RBDEBUG_TREE_INITIALIZER(t) /* nothing */
138#endif /* RBDEBUG */
139
140/*
141 * rbto_compare_nodes_fn:
142 * return a positive value if the first node > the second node.
143 * return a negative value if the first node < the second node.
144 * return 0 if they are considered same.
145 *
146 * rbto_compare_key_fn:
147 * return a positive value if the node > the key.
148 * return a negative value if the node < the key.
149 * return 0 if they are considered same.
150 */
151
152typedef signed int (*rbto_compare_nodes_fn)(void *, const void *, const void *);
153typedef signed int (*rbto_compare_key_fn)(void *, const void *, const void *);
154
155typedef struct {
156 rbto_compare_nodes_fn rbto_compare_nodes;
157 rbto_compare_key_fn rbto_compare_key;
158 size_t rbto_node_offset;
159 void *rbto_context;
160} rb_tree_ops_t;
161
162typedef struct rb_tree {
163 struct rb_node *rbt_root;
164 const rb_tree_ops_t *rbt_ops;
165 struct rb_node *rbt_minmax[2];
166#ifdef RBDEBUG
167 struct rb_node_qh rbt_nodes;
168#endif
169#ifdef RBSTATS
170 unsigned int rbt_count;
171 unsigned int rbt_insertions;
172 unsigned int rbt_removals;
173 unsigned int rbt_insertion_rebalance_calls;
174 unsigned int rbt_insertion_rebalance_passes;
175 unsigned int rbt_removal_rebalance_calls;
176 unsigned int rbt_removal_rebalance_passes;
177#endif
178} rb_tree_t;
179
180#ifdef RBSTATS
181#define RBSTAT_INC(v) ((void)((v)++))
182#define RBSTAT_DEC(v) ((void)((v)--))
183#else
184#define RBSTAT_INC(v) do { } while (0)
185#define RBSTAT_DEC(v) do { } while (0)
186#endif
187
188#define RB_TREE_INIT_TYPECHECK(t) \
189 0*sizeof(&(t) - (struct rb_tree *)0)
190
191#define RB_TREE_INITIALIZER(t, ops) \
192{ \
193 .rbt_ops = (ops) + RB_TREE_INIT_TYPECHECK(t), \
194 RBDEBUG_TREE_INITIALIZER(t) \
195}
196
197void rb_tree_init(rb_tree_t *, const rb_tree_ops_t *);
198void * rb_tree_insert_node(rb_tree_t *, void *);
199void * rb_tree_find_node(rb_tree_t *, const void *);
200void * rb_tree_find_node_geq(rb_tree_t *, const void *);
201void * rb_tree_find_node_leq(rb_tree_t *, const void *);
202void rb_tree_remove_node(rb_tree_t *, void *);
203void * rb_tree_iterate(rb_tree_t *, void *, const unsigned int);
204#ifdef RBDEBUG
205void rb_tree_check(const rb_tree_t *, bool);
206#endif
207#ifdef RBSTATS
208void rb_tree_depths(const rb_tree_t *, size_t *);
209#endif
210
211__END_DECLS
212
213#endif /* _SYS_RBTREE_H_*/