/*
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>
struct rb_node {
unsigned long rb_parent_color;
struct rb_node *rb_right;
struct rb_node *rb_left;
} __attribute__((aligned(sizeof(long))));
/* The alignment might seem pointless, but allegedly CRIS needs it */
struct rb_root {
struct rb_node *rb_node;
};
#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
#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)
/* 'empty' nodes are nodes that are known not to be inserted in an rbree */
#define RB_EMPTY_NODE(node) \
((node)->rb_parent_color == (unsigned long)(node))
#define RB_CLEAR_NODE(node) \
((node)->rb_parent_color = (unsigned long)(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 *);
struct rb_augment_callbacks {
void (*propagate)(struct rb_node *node, struct rb_node *stop);
void (*copy)(struct rb_node *old, struct rb_node *new);
void (*rotate)(struct rb_node *old, struct rb_node *new);
};
extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
extern void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment);
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
__rb_insert_augmented(node, root, augment->rotate);
}
#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
rbtype, rbaugmented, rbcompute) \
static void rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \
{ \
while (rb != stop) { \
rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
rbtype augmented = rbcompute(node); \
if (node->rbaugmented == augmented) \
break; \
node->rbaugmented = augmented; \
rb = rb_parent(&node->rbfield); \
} \
} \
static void rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
} \
static void rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
old->rbaugmented = rbcompute(old); \
} \
rbstatic const struct rb_augment_callbacks rbname = { \
rbname ## _propagate, rbname ## _copy, rbname ## _rotate \
};
/* 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 *);
/* Postorder iteration - always visit the parent after its children */
extern struct rb_node *rb_first_postorder(const struct rb_root *);
extern struct rb_node *rb_next_postorder(const struct rb_node *);
/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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;
}
#define rb_entry_safe(ptr, type, member) \
({ typeof(ptr) ____ptr = (ptr); \
____ptr ? rb_entry(____ptr, type, member) : NULL; \
})
/**
* rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
* given type safe against removal of rb_node entry
*
* @pos: the 'type *' to use as a loop cursor.
* @n: another 'type *' to use as temporary storage
* @root: 'rb_root *' of the rbtree.
* @field: the name of the rb_node field within 'type'.
*/
#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
typeof(*pos), field); 1; }); \
pos = n)
#endif /* _LINUX_RBTREE_H */
y~or5J ={Eeu磝Qk ᯘG{?+]ן?wM3X^歌>{7پK>on\jy R g/=fOroNVv~Y+ NGuÝHWyw[eQʨSb> >}Gmx[o[<{Ϯ_qF vM IENDB`
