Linux内核的红黑树RB_TREE和FreeBSD 8.0里面的AVL_TREE比较
Linux内核的红黑树RB_TREE和FreeBSD 8.0里面的AVL_TREE比较
Linux内核的红黑树RB_TREE和FreeBSD 8.0里面的AVL_TREE比较之一 RB_TREE
这里不涉及到avl树和红黑树谁优谁劣,只是谈谈在两种实现的一些细节,以及最后给出一些性能比较。
这里先给出Linux下面的红黑树的实现,因为Linux下面的两个宏定义不好直接使用,原型如下:
- #define rb_entry(ptr, type, member) container_of(ptr, type, member)
- #ifndef container_of
- /**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr: the pointer to the member.
- * @type: the type of the container struct this is embedded in.
- * @member: the name of the member within the struct.
- *
- */
- #define container_of(ptr, type, member) ({ \
- const typeof(((type *)0)->member) * __mptr = (ptr); \
- (type *)((char *)__mptr - offsetof(type, member)); })
- #endif
- #ifndef offsetof
- #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
- #endif
修改如下:
- #ifndef offsetof
- #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
- #endif
- #ifndef container_of
- /**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr: the pointer to the member.
- * @type: the type of the container struct this is embedded in.
- * @member: the name of the member within the struct.
- *
- * !!! modify the typeof marco, just use the rb_node
- */
- #define container_of(ptr, type, member) \
- (((char *)ptr) - offsetof(type, member))
- #endif
- #define rb_entry(ptr, type, member) container_of(ptr, type, member)
语义可以认为不变的。
linux的RB_TREE源代码移植到vc上后,命名为:rb_tree.h, 如下:
- /*
- 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
- 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
- #define EXPORT_SYMBOL(i)
- #pragma pack (push)
- #pragma pack(4)
- 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;
- } ;
- #pragma pack (pop)
- /* The alignment might seem pointless, but allegedly CRIS needs it */
- struct rb_root
- {
- struct rb_node *rb_node;
- int (*cmp)(void *src, void *dst);
- void (*insert)(struct rb_root *root, void *ins);
- void (*remove)(struct rb_root *root, void *del);
- };
- #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;
- }
- #ifndef offsetof
- #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
- #endif
- #ifndef container_of
- /**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr: the pointer to the member.
- * @type: the type of the container struct this is embedded in.
- * @member: the name of the member within the struct.
- *
- * !!! modify the typeof marco, just use the rb_node
- */
- #define container_of(ptr, type, member) \
- (((char *)ptr) - offsetof(type, member))
- #endif
- #define RB_ROOT (struct rb_root) { NULL, }
- #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))
- static inline void rb_init_node(struct rb_node *rb)
- {
- rb->rb_parent_color = 0;
- rb->rb_right = NULL;
- rb->rb_left = NULL;
- RB_CLEAR_NODE(rb);
- }
- extern void rb_insert_color(struct rb_node *, struct rb_root *);
- extern void rb_erase(struct rb_node *, struct rb_root *);
- typedef void (*rb_augment_f)(struct rb_node *node, void *data);
- extern void rb_augment_insert(struct rb_node *node,
- rb_augment_f func, void *data);
- extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
- extern void rb_augment_erase_end(struct rb_node *node,
- rb_augment_f func, void *data);
- /* Find logical next and previous nodes in a tree */
- extern struct rb_node *rb_next(const struct rb_node *);
- extern struct rb_node *rb_prev(const struct rb_node *);
- extern struct rb_node *rb_first(const struct rb_root *);
- extern struct rb_node *rb_last(const 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_node_node,
- 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 */
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