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