Rev 422 | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | /* |
| 2 | Red Black Trees |
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| 3 | (C) 1999 Andrea Arcangeli <andrea@suse.de> |
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| 4 | |||
| 5 | This program is free software; you can redistribute it and/or modify |
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| 6 | it under the terms of the GNU General Public License as published by |
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| 7 | the Free Software Foundation; either version 2 of the License, or |
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| 8 | (at your option) any later version. |
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| 9 | |||
| 10 | This program is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 13 | GNU General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU General Public License |
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| 16 | along with this program; if not, write to the Free Software |
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| 17 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 18 | |||
| 19 | linux/include/linux/rbtree.h |
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| 20 | |||
| 21 | To use rbtrees you'll have to implement your own insert and search cores. |
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| 22 | This will avoid us to use callbacks and to drop drammatically performances. |
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| 23 | I know it's not the cleaner way, but in C (not in C++) to get |
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| 24 | performances and genericity... |
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| 25 | |||
| 26 | Some example of insert and search follows here. The search is a plain |
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| 27 | normal search over an ordered tree. The insert instead must be implemented |
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| 28 | int two steps: as first thing the code must insert the element in |
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| 29 | order as a red leaf in the tree, then the support library function |
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| 30 | rb_insert_color() must be called. Such function will do the |
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| 31 | not trivial work to rebalance the rbtree if necessary. |
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| 32 | |||
| 33 | ----------------------------------------------------------------------- |
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| 34 | static inline struct page * rb_search_page_cache(struct inode * inode, |
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| 35 | unsigned long offset) |
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| 36 | { |
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| 37 | struct rb_node * n = inode->i_rb_page_cache.rb_node; |
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| 38 | struct page * page; |
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| 39 | |||
| 40 | while (n) |
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| 41 | { |
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| 42 | page = rb_entry(n, struct page, rb_page_cache); |
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| 43 | |||
| 44 | if (offset < page->offset) |
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| 45 | n = n->rb_left; |
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| 46 | else if (offset > page->offset) |
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| 47 | n = n->rb_right; |
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| 48 | else |
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| 49 | return page; |
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| 50 | } |
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| 51 | return NULL; |
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| 52 | } |
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| 53 | |||
| 54 | static inline struct page * __rb_insert_page_cache(struct inode * inode, |
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| 55 | unsigned long offset, |
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| 56 | struct rb_node * node) |
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| 57 | { |
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| 58 | struct rb_node ** p = &inode->i_rb_page_cache.rb_node; |
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| 59 | struct rb_node * parent = NULL; |
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| 60 | struct page * page; |
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| 61 | |||
| 62 | while (*p) |
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| 63 | { |
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| 64 | parent = *p; |
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| 65 | page = rb_entry(parent, struct page, rb_page_cache); |
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| 66 | |||
| 67 | if (offset < page->offset) |
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| 68 | p = &(*p)->rb_left; |
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| 69 | else if (offset > page->offset) |
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| 70 | p = &(*p)->rb_right; |
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| 71 | else |
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| 72 | return page; |
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| 73 | } |
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| 74 | |||
| 75 | rb_link_node(node, parent, p); |
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| 76 | |||
| 77 | return NULL; |
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| 78 | } |
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| 79 | |||
| 80 | static inline struct page * rb_insert_page_cache(struct inode * inode, |
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| 81 | unsigned long offset, |
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| 82 | struct rb_node * node) |
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| 83 | { |
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| 84 | struct page * ret; |
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| 85 | if ((ret = __rb_insert_page_cache(inode, offset, node))) |
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| 86 | goto out; |
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| 87 | rb_insert_color(node, &inode->i_rb_page_cache); |
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| 88 | out: |
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| 89 | return ret; |
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| 90 | } |
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| 91 | ----------------------------------------------------------------------- |
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| 92 | */ |
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| 93 | |||
| 94 | #ifndef _LINUX_RBTREE_H |
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| 95 | #define _LINUX_RBTREE_H |
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| 96 | |||
| 97 | #include <linux/kernel.h> |
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| 98 | #include <linux/stddef.h> |
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| 99 | |||
| 100 | struct rb_node |
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| 101 | { |
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| 102 | struct rb_node *rb_parent; |
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| 103 | int rb_color; |
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| 104 | #define RB_RED 0 |
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| 105 | #define RB_BLACK 1 |
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| 106 | struct rb_node *rb_right; |
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| 107 | struct rb_node *rb_left; |
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| 108 | }; |
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| 109 | |||
| 110 | struct rb_root |
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| 111 | { |
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| 112 | struct rb_node *rb_node; |
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| 113 | }; |
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| 114 | |||
| 115 | #define RB_ROOT (struct rb_root) { NULL, } |
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| 116 | #define rb_entry(ptr, type, member) \ |
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| 117 | ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) |
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| 118 | |||
| 119 | extern void rb_insert_color(struct rb_node *, struct rb_root *); |
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| 120 | extern void rb_erase(struct rb_node *, struct rb_root *); |
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| 121 | |||
| 122 | /* Find logical next and previous nodes in a tree */ |
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| 123 | extern struct rb_node *rb_next(struct rb_node *); |
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| 124 | extern struct rb_node *rb_prev(struct rb_node *); |
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| 125 | extern struct rb_node *rb_first(struct rb_root *); |
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| 126 | |||
| 127 | /* Fast replacement of a single node without remove/rebalance/add/rebalance */ |
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| 128 | extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, |
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| 129 | struct rb_root *root); |
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| 130 | |||
| 131 | static inline void rb_link_node(struct rb_node * node, struct rb_node * parent, |
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| 132 | struct rb_node ** rb_link) |
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| 133 | { |
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| 134 | node->rb_parent = parent; |
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| 135 | node->rb_color = RB_RED; |
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| 136 | node->rb_left = node->rb_right = NULL; |
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| 137 | |||
| 138 | *rb_link = node; |
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| 139 | } |
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| 140 | |||
| 141 | #endif /* _LINUX_RBTREE_H */ |