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/filesystems/unixfs/common/linux/kernel/include/linux/rbtree.h

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C++ Header | 161 lines | 51 code | 15 blank | 95 comment | 4 complexity | 12e2e930bd03e4ebc96d3ae2554a24f0 MD5 | raw file
  1/*
  2  Red Black Trees
  3  (C) 1999  Andrea Arcangeli <andrea@suse.de>
  4  
  5  This program is free software; you can redistribute it and/or modify
  6  it under the terms of the GNU General Public License as published by
  7  the Free Software Foundation; either version 2 of the License, or
  8  (at your option) any later version.
  9
 10  This program is distributed in the hope that it will be useful,
 11  but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13  GNU General Public License for more details.
 14
 15  You should have received a copy of the GNU General Public License
 16  along with this program; if not, write to the Free Software
 17  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 18
 19  linux/include/linux/rbtree.h
 20
 21  To use rbtrees you'll have to implement your own insert and search cores.
 22  This will avoid us to use callbacks and to drop drammatically performances.
 23  I know it's not the cleaner way,  but in C (not in C++) to get
 24  performances and genericity...
 25
 26  Some example of insert and search follows here. The search is a plain
 27  normal search over an ordered tree. The insert instead must be implemented
 28  int two steps: as first thing the code must insert the element in
 29  order as a red leaf in the tree, then the support library function
 30  rb_insert_color() must be called. Such function will do the
 31  not trivial work to rebalance the rbtree if necessary.
 32
 33-----------------------------------------------------------------------
 34static inline struct page * rb_search_page_cache(struct inode * inode,
 35						 unsigned long offset)
 36{
 37	struct rb_node * n = inode->i_rb_page_cache.rb_node;
 38	struct page * page;
 39
 40	while (n)
 41	{
 42		page = rb_entry(n, struct page, rb_page_cache);
 43
 44		if (offset < page->offset)
 45			n = n->rb_left;
 46		else if (offset > page->offset)
 47			n = n->rb_right;
 48		else
 49			return page;
 50	}
 51	return NULL;
 52}
 53
 54static inline struct page * __rb_insert_page_cache(struct inode * inode,
 55						   unsigned long offset,
 56						   struct rb_node * node)
 57{
 58	struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
 59	struct rb_node * parent = NULL;
 60	struct page * page;
 61
 62	while (*p)
 63	{
 64		parent = *p;
 65		page = rb_entry(parent, struct page, rb_page_cache);
 66
 67		if (offset < page->offset)
 68			p = &(*p)->rb_left;
 69		else if (offset > page->offset)
 70			p = &(*p)->rb_right;
 71		else
 72			return page;
 73	}
 74
 75	rb_link_node(node, parent, p);
 76
 77	return NULL;
 78}
 79
 80static inline struct page * rb_insert_page_cache(struct inode * inode,
 81						 unsigned long offset,
 82						 struct rb_node * node)
 83{
 84	struct page * ret;
 85	if ((ret = __rb_insert_page_cache(inode, offset, node)))
 86		goto out;
 87	rb_insert_color(node, &inode->i_rb_page_cache);
 88 out:
 89	return ret;
 90}
 91-----------------------------------------------------------------------
 92*/
 93
 94#ifndef	_LINUX_RBTREE_H
 95#define	_LINUX_RBTREE_H
 96
 97#include <linux/kernel.h>
 98#include <linux/stddef.h>
 99
100struct rb_node
101{
102	unsigned long  rb_parent_color;
103#define	RB_RED		0
104#define	RB_BLACK	1
105	struct rb_node *rb_right;
106	struct rb_node *rb_left;
107} __attribute__((aligned(sizeof(long))));
108    /* The alignment might seem pointless, but allegedly CRIS needs it */
109
110struct rb_root
111{
112	struct rb_node *rb_node;
113};
114
115
116#define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
117#define rb_color(r)   ((r)->rb_parent_color & 1)
118#define rb_is_red(r)   (!rb_color(r))
119#define rb_is_black(r) rb_color(r)
120#define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
121#define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
122
123static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
124{
125	rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
126}
127static inline void rb_set_color(struct rb_node *rb, int color)
128{
129	rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
130}
131
132#define RB_ROOT	(struct rb_root) { NULL, }
133#define	rb_entry(ptr, type, member) container_of(ptr, type, member)
134
135#define RB_EMPTY_ROOT(root)	((root)->rb_node == NULL)
136#define RB_EMPTY_NODE(node)	(rb_parent(node) == node)
137#define RB_CLEAR_NODE(node)	(rb_set_parent(node, node))
138
139extern void rb_insert_color(struct rb_node *, struct rb_root *);
140extern void rb_erase(struct rb_node *, struct rb_root *);
141
142/* Find logical next and previous nodes in a tree */
143extern struct rb_node *rb_next(struct rb_node *);
144extern struct rb_node *rb_prev(struct rb_node *);
145extern struct rb_node *rb_first(struct rb_root *);
146extern struct rb_node *rb_last(struct rb_root *);
147
148/* Fast replacement of a single node without remove/rebalance/add/rebalance */
149extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
150			    struct rb_root *root);
151
152static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
153				struct rb_node ** rb_link)
154{
155	node->rb_parent_color = (unsigned long )parent;
156	node->rb_left = node->rb_right = NULL;
157
158	*rb_link = node;
159}
160
161#endif	/* _LINUX_RBTREE_H */