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Diffstat (limited to '')
| -rw-r--r-- | lib/ext2fs/rbtree.h | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/lib/ext2fs/rbtree.h b/lib/ext2fs/rbtree.h new file mode 100644 index 0000000..790f5c1 --- /dev/null +++ b/lib/ext2fs/rbtree.h @@ -0,0 +1,183 @@ +/* + 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 dramatically 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 + in two steps: First, the code must insert the element in order as a red leaf + in the tree, and 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 <stdlib.h> +#include <stdint.h> +#include "compiler.h" + +#if __GNUC_PREREQ (4, 6) +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wunused-function" +#endif + +struct rb_node +{ + uintptr_t 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 ext2fs_rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3)) +#define ext2fs_rb_color(r) ((r)->rb_parent_color & 1) +#define ext2fs_rb_is_red(r) (!ext2fs_rb_color(r)) +#define ext2fs_rb_is_black(r) ext2fs_rb_color(r) +#define ext2fs_rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0) +#define ext2fs_rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0) + +static inline void ext2fs_rb_set_parent(struct rb_node *rb, struct rb_node *p) +{ + rb->rb_parent_color = (rb->rb_parent_color & 3) | (uintptr_t)p; +} +static inline void ext2fs_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, } +#define ext2fs_rb_entry(ptr, type, member) container_of(ptr, type, member) + +static inline int ext2fs_rb_empty_root(struct rb_root *root) +{ + return root->rb_node == NULL; +} + +static inline int ext2fs_rb_empty_node(struct rb_node *node) +{ + return ext2fs_rb_parent(node) == node; +} + +static inline void ext2fs_rb_clear_node(struct rb_node *node) +{ + ext2fs_rb_set_parent(node, node); +} + +extern void ext2fs_rb_insert_color(struct rb_node *, struct rb_root *); +extern void ext2fs_rb_erase(struct rb_node *, struct rb_root *); + +/* Find logical next and previous nodes in a tree */ +extern struct rb_node *ext2fs_rb_next(struct rb_node *); +extern struct rb_node *ext2fs_rb_prev(struct rb_node *); +extern struct rb_node *ext2fs_rb_first(const struct rb_root *); +extern struct rb_node *ext2fs_rb_last(const struct rb_root *); + +/* Fast replacement of a single node without remove/rebalance/add/rebalance */ +extern void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new, + struct rb_root *root); + +static inline void ext2fs_rb_link_node(struct rb_node * node, + struct rb_node * parent, + struct rb_node ** rb_link) +{ + node->rb_parent_color = (uintptr_t)parent; + node->rb_left = node->rb_right = NULL; + + *rb_link = node; +} + +#if __GNUC_PREREQ (4, 6) +#pragma GCC diagnostic pop +#endif + +#endif /* _LINUX_RBTREE_H */ |