Lukas Czerner | 5db745a | 2011-12-15 20:56:27 -0500 | [diff] [blame] | 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 | in two steps: First, the code must insert the element in order as a red leaf |
| 29 | in the tree, and then the support library function rb_insert_color() must |
| 30 | be called. Such function will do the not trivial work to rebalance the |
| 31 | 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 <stdlib.h> |
| 98 | |
| 99 | #undef offsetof |
| 100 | #ifdef __compiler_offsetof |
| 101 | #define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER) |
| 102 | #else |
| 103 | #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) |
| 104 | #endif |
| 105 | |
| 106 | #define container_of(ptr, type, member) ({ \ |
Theodore Ts'o | e64e676 | 2012-04-05 12:13:05 -0700 | [diff] [blame] | 107 | const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \ |
Lukas Czerner | 5db745a | 2011-12-15 20:56:27 -0500 | [diff] [blame] | 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 ext2fs_rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3)) |
| 127 | #define ext2fs_rb_color(r) ((r)->rb_parent_color & 1) |
| 128 | #define ext2fs_rb_is_red(r) (!ext2fs_rb_color(r)) |
| 129 | #define ext2fs_rb_is_black(r) ext2fs_rb_color(r) |
| 130 | #define ext2fs_rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0) |
| 131 | #define ext2fs_rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0) |
| 132 | |
| 133 | static inline void ext2fs_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 ext2fs_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 ext2fs_rb_entry(ptr, type, member) container_of(ptr, type, member) |
| 144 | |
| 145 | #define EXT2FS_RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) |
| 146 | #define EXT2FS_RB_EMPTY_NODE(node) (ext2fs_rb_parent(node) == node) |
| 147 | #define EXT2FS_RB_CLEAR_NODE(node) (ext2fs_rb_set_parent(node, node)) |
| 148 | |
| 149 | extern void ext2fs_rb_insert_color(struct rb_node *, struct rb_root *); |
| 150 | extern void ext2fs_rb_erase(struct rb_node *, struct rb_root *); |
| 151 | |
| 152 | typedef void (*rb_augment_f)(struct rb_node *node, void *data); |
| 153 | |
| 154 | extern void ext2fs_rb_augment_insert(struct rb_node *node, |
| 155 | rb_augment_f func, void *data); |
| 156 | extern struct rb_node *ext2fs_rb_augment_erase_begin(struct rb_node *node); |
| 157 | extern void ext2fs_rb_augment_erase_end(struct rb_node *node, |
| 158 | rb_augment_f func, void *data); |
| 159 | |
| 160 | /* Find logical next and previous nodes in a tree */ |
Theodore Ts'o | e48bf25 | 2013-05-19 18:50:10 -0400 | [diff] [blame] | 161 | extern struct rb_node *ext2fs_rb_next(struct rb_node *); |
| 162 | extern struct rb_node *ext2fs_rb_prev(struct rb_node *); |
Lukas Czerner | 5db745a | 2011-12-15 20:56:27 -0500 | [diff] [blame] | 163 | extern struct rb_node *ext2fs_rb_first(const struct rb_root *); |
| 164 | extern struct rb_node *ext2fs_rb_last(const struct rb_root *); |
| 165 | |
| 166 | /* Fast replacement of a single node without remove/rebalance/add/rebalance */ |
| 167 | extern void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new, |
| 168 | struct rb_root *root); |
| 169 | |
| 170 | static inline void ext2fs_rb_link_node(struct rb_node * node, |
| 171 | struct rb_node * parent, |
| 172 | struct rb_node ** rb_link) |
| 173 | { |
| 174 | node->rb_parent_color = (unsigned long )parent; |
| 175 | node->rb_left = node->rb_right = NULL; |
| 176 | |
| 177 | *rb_link = node; |
| 178 | } |
| 179 | |
| 180 | #endif /* _LINUX_RBTREE_H */ |