/*

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)

{

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 <linux/kernel.h>

#include <linux/stddef.h>

*/

#ifndef PACKED

#define PACKED __attribute__ ((packed))

#endif

struct PACKED rb_node

{

struct rb_node *rb_parent;

#define RB_RED 0

#define RB_BLACK 1

struct rb_node *rb_right;

struct rb_node *rb_left;

char rb_color;

};

struct rb_root

{

struct rb_node *rb_node;

};

// Copy from linux kernel 2.6 source (kernel.h, stddef.h)

#define container_of(ptr, type, member) ({ \

const typeof( ((type *)0)->member ) *__mptr = (ptr); \

(type *)( (char *)__mptr - offsetof(type,member) );})

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

#define RB_ROOT (struct rb_root) { NULL, }

#define rb_entry(ptr, type, member) container_of(ptr, type, member)

extern void rb_insert_color(struct rb_node *, struct rb_root *);

extern void rb_erase(struct rb_node *, struct rb_root *);

/* Find logical next and previous nodes in a tree */

extern struct rb_node *rb_next(struct rb_node *);

extern struct rb_node *rb_prev(struct rb_node *);

extern struct rb_node *rb_first(struct rb_root *);

extern struct rb_node *rb_last(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 *rbnew,

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 = parent;

node->rb_color = RB_RED;

node->rb_left = node->rb_right = NULL;

*rb_link = node;

}

#endif /* _LINUX_RBTREE_H */