/* 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) { rb_node_t * 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, rb_node_t * node) { rb_node_t ** p = &inode->i_rb_page_cache.rb_node; rb_node_t * 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, rb_node_t * 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; } ----------------------------------------------------------------------- */
/* 获取红黑树中节点node的前序节点 */ struct rb_node *rb_prev(struct rb_node *node) { /* If we have a left-hand child, go down and then right as far as we can. */ if (node->rb_left) { node = node->rb_left; while (node->rb_right) node = node->rb_right; return node; }
/* No left-hand children. Go up till we find an ancestor which is a right-hand child of its parent */ while (node->rb_parent && node == node->rb_parent->rb_left) node = node->rb_parent;
