| /* |
| Red Black Trees |
| (C) 1999 Andrea Arcangeli <andrea@suse.de> |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| linux/include/linux/rbtree.h |
| |
| To use rbtrees you'll have to implement your own insert and search cores. |
| This will avoid us to use callbacks and to drop drammatically performances. |
| I know it's not the cleaner way, but in C (not in C++) to get |
| performances and genericity... |
| |
| Some example of insert and search follows here. The search is a plain |
| normal search over an ordered tree. The insert instead must be implemented |
| int two steps: as first thing the code must insert the element in |
| order as a red leaf in the tree, then the support library function |
| rb_insert_color() must be called. Such function will do the |
| not trivial work to rebalance the rbtree if necessary. |
| |
| ----------------------------------------------------------------------- |
| static inline struct page * rb_search_page_cache(struct inode * inode, |
| unsigned long offset) |
| { |
| struct rb_node * n = inode->i_rb_page_cache.rb_node; |
| struct page * page; |
| |
| while (n) |
| { |
| page = rb_entry(n, struct page, rb_page_cache); |
| |
| if (offset < page->offset) |
| n = n->rb_left; |
| else if (offset > page->offset) |
| n = n->rb_right; |
| else |
| return page; |
| } |
| return NULL; |
| } |
| |
| static inline struct page * __rb_insert_page_cache(struct inode * inode, |
| unsigned long offset, |
| struct rb_node * node) |
| { |
| struct rb_node ** p = &inode->i_rb_page_cache.rb_node; |
| struct rb_node * parent = NULL; |
| struct page * page; |
| |
| while (*p) |
| { |
| parent = *p; |
| page = rb_entry(parent, struct page, rb_page_cache); |
| |
| if (offset < page->offset) |
| p = &(*p)->rb_left; |
| else if (offset > page->offset) |
| p = &(*p)->rb_right; |
| else |
| return page; |
| } |
| |
| rb_link_node(node, parent, p); |
| |
| return NULL; |
| } |
| |
| static inline struct page * rb_insert_page_cache(struct inode * inode, |
| unsigned long offset, |
| struct rb_node * node) |
| { |
| struct page * ret; |
| if ((ret = __rb_insert_page_cache(inode, offset, node))) |
| goto out; |
| rb_insert_color(node, &inode->i_rb_page_cache); |
| out: |
| return ret; |
| } |
| ----------------------------------------------------------------------- |
| */ |
| |
| #ifndef _LINUX_RBTREE_H |
| #define _LINUX_RBTREE_H |
| |
| #include <linux/kernel.h> |
| #include <linux/stddef.h> |
| |
| struct rb_node |
| { |
| unsigned long rb_parent_color; |
| #define RB_RED 0 |
| #define RB_BLACK 1 |
| struct rb_node *rb_right; |
| struct rb_node *rb_left; |
| } __attribute__((aligned(sizeof(long)))); |
| /* The alignment might seem pointless, but allegedly CRIS needs it */ |
| |
| struct rb_root |
| { |
| struct rb_node *rb_node; |
| }; |
| |
| |
| #define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3)) |
| #define rb_color(r) ((r)->rb_parent_color & 1) |
| #define rb_is_red(r) (!rb_color(r)) |
| #define rb_is_black(r) rb_color(r) |
| #define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0) |
| #define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0) |
| |
| static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) |
| { |
| rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p; |
| } |
| static inline void rb_set_color(struct rb_node *rb, int color) |
| { |
| rb->rb_parent_color = (rb->rb_parent_color & ~1) | color; |
| } |
| |
| #define RB_ROOT (struct rb_root) { NULL, } |
| |
| /* Newer gcc versions take care of exporting this */ |
| #ifndef offsetof |
| #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) |
| #endif |
| |
| #define container_of(ptr, type, member) ({ \ |
| const typeof( ((type *)0)->member ) *__mptr = (ptr); \ |
| (type *)( (char *)__mptr - offsetof(type,member) );}) |
| |
| #define rb_entry(ptr, type, member) container_of(ptr, type, member) |
| |
| #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) |
| #define RB_EMPTY_NODE(node) (rb_parent(node) == node) |
| #define RB_CLEAR_NODE(node) (rb_set_parent(node, node)) |
| |
| extern void rb_insert_color(struct rb_node *, struct rb_root *); |
| extern void rb_erase(struct rb_node *, struct rb_root *); |
| |
| /* Find logical next and previous nodes in a tree */ |
| extern struct rb_node *rb_next(struct rb_node *); |
| extern struct rb_node *rb_prev(struct rb_node *); |
| extern struct rb_node *rb_first(struct rb_root *); |
| extern struct rb_node *rb_last(struct rb_root *); |
| |
| /* Fast replacement of a single node without remove/rebalance/add/rebalance */ |
| extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, |
| struct rb_root *root); |
| |
| static inline void rb_link_node(struct rb_node * node, struct rb_node * parent, |
| struct rb_node ** rb_link) |
| { |
| node->rb_parent_color = (unsigned long )parent; |
| node->rb_left = node->rb_right = NULL; |
| |
| *rb_link = node; |
| } |
| |
| #endif /* _LINUX_RBTREE_H */ |