/*
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...
See Documentation/rbtree.txt for documentation and samples.
*/
#ifndef _LINUX_RBTREE_H
#define _LINUX_RBTREE_H
#include <stdbool.h>
typedef struct rb_node {
unsigned long __rb_parent_color;
struct rb_node *rb_right;
struct rb_node *rb_left;
} rb_node_t;
typedef struct rb_root {
struct rb_node *rb_node;
} rb_root_t;
/*
* Leftmost-cached rbtrees.
*
* We do not cache the rightmost node based on footprint
* size vs number of potential users that could benefit
* from O(1) rb_last(). Just not worth it, users that want
* this feature can always implement the logic explicitly.
* Furthermore, users that want to cache both pointers may
* find it a bit asymmetric, but that's ok.
*/
typedef struct rb_root_cached {
struct rb_root rb_root;
struct rb_node *rb_leftmost;
} rb_root_cached_t;
/* Copy from linux kernel 2.6 source (kernel.h, stddef.h) */
#ifndef container_of
# define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
#endif
#ifndef offsetof
# define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
#define RB_ROOT (struct rb_root) { NULL, }
#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, 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 rbtree */
#define RB_EMPTY_NODE(node) \
((node)->__rb_parent_color == (unsigned long)(node))
#define RB_CLEAR_NODE(node) \
((node)->__rb_parent_color = (unsigned long)(node))
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(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 *);
extern void rb_insert_color_cached(struct rb_node *,
struct rb_root_cached *, bool);
extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
/* Same as rb_first(), but O(1) */
#define rb_first_cached(root) (root)->rb_leftmost
/* 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);
extern void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new,
struct rb_root *root);
extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
struct rb_root_cached *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;
}
#ifdef UNUSED_CODE
static inline void rb_link_node_rcu(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;
rcu_assign_pointer(*rb_link, node);
}
#endif
#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 in post-order over rb_root of
* given type allowing the backing memory of @pos to be invalidated
*
* @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'.
*
* rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
* list_for_each_entry_safe() and allows the iteration to continue independent
* of changes to @pos by the body of the loop.
*
* Note, however, that it cannot handle other modifications that re-order the
* rbtree it is iterating over. This includes calling rb_erase() on @pos, as
* rb_erase() may rebalance the tree, causing us to miss some nodes.
*/
#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)
/* The following are keepalived specific code */
/**
* rb_search - Search for a specific value in rbtree
* @root: the rbtree root.
* @key: the key to seach for in your rbtree.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_search(root, key, member, compar) \
({ \
rb_node_t *__n = (root)->rb_node; \
typeof(key) __ret = NULL, __data; \
\
while (__n) { \
__data = rb_entry(__n, typeof(*key), member); \
int __cmp = compar(key, __data); \
\
if (__cmp < 0) \
__n = __n->rb_left; \
else if (__cmp > 0) \
__n = __n->rb_right; \
else { \
__ret = __data; \
break; \
} \
} \
__ret; \
})
/**
* rb_search_first - Search for the first greater value in rbtree
* @root: the rbtree root.
* @key: the key to seach for in your rbtree.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_search_first(root, key, member, compar) \
({ \
rb_node_t *__n = (root)->rb_node; \
typeof(key) __ret = NULL, __data; \
\
while (__n) { \
__data = rb_entry(__n, typeof(*key), member); \
int __cmp = compar(key, __data); \
\
if (__cmp < 0) { \
__ret = __data; \
__n = __n->rb_left; \
} else if (__cmp > 0) \
__n = __n->rb_right; \
else { \
__ret = __data; \
break; \
} \
} \
if (!__ret && !RB_EMPTY_ROOT(root)) \
__ret = rb_entry(rb_first(root), typeof(*key), member); \
__ret; \
})
/**
* rb_insert - Insert a new node into your rbtree
* @root: the rbtree root.
* @new: the node to insert.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_insert(root, new, member, compar) \
({ \
rb_node_t **__n = &(root)->rb_node, *__parent = NULL; \
typeof(new) __old = NULL, __data; \
\
while (*__n) { \
__data = rb_entry(*__n, typeof(*new), member); \
int __cmp = compar(new, __data); \
\
__parent = *__n; \
if (__cmp < 0) \
__n = &((*__n)->rb_left); \
else if (__cmp > 0) \
__n = &((*__n)->rb_right); \
else { \
__old = __data; \
break; \
} \
} \
\
if (__old == NULL) { \
/* Add new node and rebalance tree. */ \
rb_link_node(&((new)->member), __parent, __n); \
rb_insert_color(&((new)->member), root); \
} \
\
__old; \
})
/**
* rb_insert - Insert & Sort a new node into your rbtree
* @root: the rbtree root.
* @new: the node to insert.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_insert_sort(root, new, member, compar) \
({ \
rb_node_t **__n = &(root)->rb_node, *__parent = NULL; \
typeof(new) __data; \
\
while (*__n) { \
__data = rb_entry(*__n, typeof(*new), member); \
int __cmp = compar(new, __data); \
\
__parent = *__n; \
if (__cmp <= 0) \
__n = &((*__n)->rb_left); \
else if (__cmp > 0) \
__n = &((*__n)->rb_right); \
} \
\
/* Add new node and rebalance tree. */ \
rb_link_node(&((new)->member), __parent, __n); \
rb_insert_color(&((new)->member), root); \
})
/**
* rb_insert_cached - Insert & Sort a new node into your cached rbtree
* @root: the rbtree root.
* @new: the node to insert.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_insert_sort_cached(root, new, member, compar) \
({ \
rb_node_t **__n = &(root)->rb_root.rb_node, *__parent = NULL; \
typeof(new) __data; \
\
while (*__n) { \
__data = rb_entry(*__n, typeof(*new), member); \
int __cmp = compar(new, __data); \
\
__parent = *__n; \
if (__cmp <= 0) \
__n = &((*__n)->rb_left); \
else if (__cmp > 0) \
__n = &((*__n)->rb_right); \
} \
/* Add new node and rebalance tree. */ \
rb_link_node(&((new)->member), __parent, __n); \
rb_insert_color_cached(&((new)->member), root, \
!(root)->rb_leftmost || __n == &(root)->rb_leftmost->rb_left); \
})
/**
* rb_for_each_entry - Iterate over rbtree of given type
* @pos: the type * to use as a loop cursor.
* @root: the rbtree root.
* @member: the name of the rb_node within the struct.
*/
#define rb_for_each_entry(pos, root, member) \
for (pos = rb_entry_safe(rb_first(root), typeof(*pos), member); \
pos; pos = rb_entry_safe(rb_next(&pos->member), typeof(*pos), member))
/**
* rb_for_each_entry_safe - Iterate over rbtree of given type safe against removal
* @pos: the type * to use as a loop cursor.
* @root: the rbtree root.
* @member: the name of the rb_node within the struct.
*/
#define rb_for_each_entry_safe(pos, n, root, member) \
for (pos = rb_entry_safe(rb_first(root), typeof(*pos), member); \
pos && (n = rb_entry_safe(rb_next(&pos->member), typeof(*n), member), 1); \
pos = n)
/**
* rb_for_each_entry_cached - Iterate over cached rbtree of given type
* @pos: the type * to use as a loop cursor.
* @root: the rbtree root.
* @member: the name of the rb_node within the struct.
*/
#define rb_for_each_entry_cached(pos, root, member) \
for (pos = rb_entry_safe(rb_first_cached(root), typeof(*pos), member); \
pos; pos = rb_entry_safe(rb_next(&pos->member), typeof(*pos), member))
/**
* rb_for_each_entry_safe_cached - Iterate over cached rbtree of given type
* @pos: the type * to use as a loop cursor.
* @root: the rbtree root.
* @member: the name of the rb_node within the struct.
*/
#define rb_for_each_entry_safe_cached(pos, n, root, member) \
for (pos = rb_entry_safe(rb_first_cached(root), typeof(*pos), member); \
pos && (n = rb_entry_safe(rb_next(&pos->member), typeof(*n), member), 1); \
pos = n)
/**
* rb_for_each_entry_from - Iterate over rbtree of given type from the given point
* @pos: the type * to use as a loop cursor.
* @root: the rbtree root.
* @member: the name of the rb_node within the struct.
*/
#define rb_for_each_entry_from(pos, root, member) \
for (rb_node_t *n = &pos->member; \
n && pos = rb_entry(n, typeof(*pos), member); \
n = rb_next(n))
/**
* rb_move_cached - Move node to new position in tree
* @root: the rbtree root.
* @node: the node to move.
* @member: the name of the rb_node within the struct.
* @compar: the name of the comparison function to use.
*/
#define rb_move_cached(root, node, member, compar) \
({ \
rb_node_t *prev_node, *next_node; \
typeof(node) prev, next; \
\
prev_node = rb_prev(&node->member); \
next_node = rb_next(&node->member); \
\
if (prev_node || next_node) { \
prev = rb_entry_safe(prev_node, typeof(*node), member); \
next = rb_entry_safe(next_node, typeof(*node), member); \
\
/* If node is between our predecessor and sucessor, \
* it can stay where it is */ \
if ((prev && compar(prev, node) > 0) || \
(next && compar(next, node) < 0)) { \
/* Can this be optimised? */ \
rb_erase_cached(&node->member, root); \
rb_insert_sort_cached(root, node, member, compar); \
} \
} \
})
#endif /* _LINUX_RBTREE_H */