Add gtod_reduce option
[fio.git] / rbtree.h
CommitLineData
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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-----------------------------------------------------------------------
34static 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
54static 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
80static 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
3902866c 97#include <stdlib.h>
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98
99struct rb_node
100{
44b5374f 101 unsigned long rb_parent_color;
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102#define RB_RED 0
103#define RB_BLACK 1
104 struct rb_node *rb_right;
105 struct rb_node *rb_left;
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106} __attribute__((aligned(sizeof(long))));
107 /* The alignment might seem pointless, but allegedly CRIS needs it */
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108
109struct rb_root
110{
111 struct rb_node *rb_node;
112};
113
4b87898e 114
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115#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
116#define rb_color(r) ((r)->rb_parent_color & 1)
117#define rb_is_red(r) (!rb_color(r))
118#define rb_is_black(r) rb_color(r)
119#define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
120#define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0)
121
122static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
123{
124 rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
125}
126static inline void rb_set_color(struct rb_node *rb, int color)
127{
128 rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
129}
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130
131#define RB_ROOT (struct rb_root) { NULL, }
132#define rb_entry(ptr, type, member) container_of(ptr, type, member)
133
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134#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
135#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
136#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
137
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138extern void rb_insert_color(struct rb_node *, struct rb_root *);
139extern void rb_erase(struct rb_node *, struct rb_root *);
140
141/* Find logical next and previous nodes in a tree */
4b87898e 142extern struct rb_node *rb_first(struct rb_root *);
44b5374f 143
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144static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
145 struct rb_node ** rb_link)
146{
44b5374f 147 node->rb_parent_color = (unsigned long )parent;
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148 node->rb_left = node->rb_right = NULL;
149
150 *rb_link = node;
151}
152
153#endif /* _LINUX_RBTREE_H */