libosmocore  UNKNOWN
Osmocom core library
linuxrbtree.h
1 /*
2  Red Black Trees
3  (C) 1999 Andrea Arcangeli <andrea@suse.de>
4 
5  This program is free software; you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation; either version 2 of the License, or
8  (at your option) any later version.
9 
10  This program is distributed in the hope that it will be useful,
11  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  GNU General Public License for more details.
14 
15  You should have received a copy of the GNU General Public License
16  along with this program; if not, write to the Free Software
17  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 
19  linux/include/linux/rbtree.h
20 
21  To use rbtrees you'll have to implement your own insert and search cores.
22  This will avoid us to use callbacks and to drop drammatically performances.
23  I know it's not the cleaner way, but in C (not in C++) to get
24  performances and genericity...
25 
26  Some example of insert and search follows here. The search is a plain
27  normal search over an ordered tree. The insert instead must be implemented
28  int two steps: as first thing the code must insert the element in
29  order as a red leaf in the tree, then the support library function
30  rb_insert_color() must be called. Such function will do the
31  not trivial work to rebalance the rbtree if necessary.
32 
33 -----------------------------------------------------------------------
34 static inline struct page * rb_search_page_cache(struct inode * inode,
35  unsigned long offset)
36 {
37  struct rb_node * n = inode->i_rb_page_cache.rb_node;
38  struct page * page;
39 
40  while (n)
41  {
42  page = rb_entry(n, struct page, rb_page_cache);
43 
44  if (offset < page->offset)
45  n = n->rb_left;
46  else if (offset > page->offset)
47  n = n->rb_right;
48  else
49  return page;
50  }
51  return NULL;
52 }
53 
54 static inline struct page * __rb_insert_page_cache(struct inode * inode,
55  unsigned long offset,
56  struct rb_node * node)
57 {
58  struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
59  struct rb_node * parent = NULL;
60  struct page * page;
61 
62  while (*p)
63  {
64  parent = *p;
65  page = rb_entry(parent, struct page, rb_page_cache);
66 
67  if (offset < page->offset)
68  p = &(*p)->rb_left;
69  else if (offset > page->offset)
70  p = &(*p)->rb_right;
71  else
72  return page;
73  }
74 
75  rb_link_node(node, parent, p);
76 
77  return NULL;
78 }
79 
80 static inline struct page * rb_insert_page_cache(struct inode * inode,
81  unsigned long offset,
82  struct rb_node * node)
83 {
84  struct page * ret;
85  if ((ret = __rb_insert_page_cache(inode, offset, node)))
86  goto out;
87  rb_insert_color(node, &inode->i_rb_page_cache);
88  out:
89  return ret;
90 }
91 -----------------------------------------------------------------------
92 */
93 
94 #pragma once
95 
96 #include <stdlib.h>
97 
98 struct rb_node
99 {
100  unsigned long rb_parent_color;
101 #define RB_RED 0
102 #define RB_BLACK 1
103  struct rb_node *rb_right;
104  struct rb_node *rb_left;
105 } __attribute__((aligned(sizeof(long))));
106  /* The alignment might seem pointless, but allegedly CRIS needs it */
107 
108 struct rb_root
109 {
110  struct rb_node *rb_node;
111 };
112 
113 
114 #define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
115 #define rb_color(r) ((r)->rb_parent_color & 1)
116 #define rb_is_red(r) (!rb_color(r))
117 #define rb_is_black(r) rb_color(r)
118 #define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
119 #define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0)
120 
121 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
122 {
123  rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
124 }
125 static inline void rb_set_color(struct rb_node *rb, int color)
126 {
127  rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
128 }
129 
130 #define RB_ROOT { NULL, }
131 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
132 
133 #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
134 #define RB_EMPTY_NODE(node) (rb_parent(node) == node)
135 #define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
136 
137 extern void rb_insert_color(struct rb_node *, struct rb_root *);
138 extern void rb_erase(struct rb_node *, struct rb_root *);
139 
140 /* Find logical next and previous nodes in a tree */
141 extern struct rb_node *rb_next(const struct rb_node *);
142 extern struct rb_node *rb_prev(const struct rb_node *);
143 extern struct rb_node *rb_first(const struct rb_root *);
144 extern struct rb_node *rb_last(const struct rb_root *);
145 
146 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
147 extern void rb_replace_node(struct rb_node *victim, struct rb_node *_new,
148  struct rb_root *root);
149 
150 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
151  struct rb_node ** rb_link)
152 {
153  node->rb_parent_color = (unsigned long )parent;
154  node->rb_left = node->rb_right = NULL;
155 
156  *rb_link = node;
157 }
Definition: linuxrbtree.h:108
Definition: linuxrbtree.h:98