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35a50c8a ACM |
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 | #ifndef _LINUX_RBTREE_H | |
95 | #define _LINUX_RBTREE_H | |
96 | ||
97 | #include <stddef.h> | |
98 | ||
99 | /** | |
100 | * container_of - cast a member of a structure out to the containing structure | |
101 | * @ptr: the pointer to the member. | |
102 | * @type: the type of the container struct this is embedded in. | |
103 | * @member: the name of the member within the struct. | |
104 | * | |
105 | */ | |
106 | #define container_of(ptr, type, member) ({ \ | |
107 | const typeof( ((type *)0)->member ) *__mptr = (ptr); \ | |
108 | (type *)( (char *)__mptr - offsetof(type,member) );}) | |
109 | ||
110 | struct rb_node | |
111 | { | |
112 | unsigned long rb_parent_color; | |
113 | #define RB_RED 0 | |
114 | #define RB_BLACK 1 | |
115 | struct rb_node *rb_right; | |
116 | struct rb_node *rb_left; | |
117 | } __attribute__((aligned(sizeof(long)))); | |
118 | /* The alignment might seem pointless, but allegedly CRIS needs it */ | |
119 | ||
120 | struct rb_root | |
121 | { | |
122 | struct rb_node *rb_node; | |
123 | }; | |
124 | ||
125 | ||
126 | #define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3)) | |
127 | #define rb_color(r) ((r)->rb_parent_color & 1) | |
128 | #define rb_is_red(r) (!rb_color(r)) | |
129 | #define rb_is_black(r) rb_color(r) | |
130 | #define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0) | |
131 | #define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0) | |
132 | ||
133 | static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) | |
134 | { | |
135 | rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p; | |
136 | } | |
137 | static inline void rb_set_color(struct rb_node *rb, int color) | |
138 | { | |
139 | rb->rb_parent_color = (rb->rb_parent_color & ~1) | color; | |
140 | } | |
141 | ||
142 | #define RB_ROOT (struct rb_root) { NULL, } | |
143 | #define rb_entry(ptr, type, member) container_of(ptr, type, member) | |
144 | ||
145 | #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) | |
146 | #define RB_EMPTY_NODE(node) (rb_parent(node) == node) | |
147 | #define RB_CLEAR_NODE(node) (rb_set_parent(node, node)) | |
148 | ||
149 | extern void rb_insert_color(struct rb_node *, struct rb_root *); | |
150 | extern void rb_erase(struct rb_node *, struct rb_root *); | |
151 | ||
152 | /* Find logical next and previous nodes in a tree */ | |
153 | extern struct rb_node *rb_next(const struct rb_node *); | |
154 | extern struct rb_node *rb_prev(const struct rb_node *); | |
155 | extern struct rb_node *rb_first(const struct rb_root *); | |
156 | extern struct rb_node *rb_last(const struct rb_root *); | |
157 | ||
158 | /* Fast replacement of a single node without remove/rebalance/add/rebalance */ | |
159 | extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, | |
160 | struct rb_root *root); | |
161 | ||
162 | static inline void rb_link_node(struct rb_node * node, struct rb_node * parent, | |
163 | struct rb_node ** rb_link) | |
164 | { | |
165 | node->rb_parent_color = (unsigned long )parent; | |
166 | node->rb_left = node->rb_right = NULL; | |
167 | ||
168 | *rb_link = node; | |
169 | } | |
170 | ||
171 | #endif /* _LINUX_RBTREE_H */ |