281 lines
8.1 KiB
C
281 lines
8.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
Red Black Trees
|
|
(C) 1999 Andrea Arcangeli <andrea@suse.de>
|
|
(C) 2002 David Woodhouse <dwmw2@infradead.org>
|
|
(C) 2012 Michel Lespinasse <walken@google.com>
|
|
|
|
|
|
linux/include/linux/rbtree_augmented.h
|
|
*/
|
|
|
|
#ifndef _LINUX_RBTREE_AUGMENTED_H
|
|
#define _LINUX_RBTREE_AUGMENTED_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/rbtree.h>
|
|
#include <linux/rcupdate.h>
|
|
|
|
/*
|
|
* Please note - only struct rb_augment_callbacks and the prototypes for
|
|
* rb_insert_augmented() and rb_erase_augmented() are intended to be public.
|
|
* The rest are implementation details you are not expected to depend on.
|
|
*
|
|
* See Documentation/rbtree.txt for documentation and samples.
|
|
*/
|
|
|
|
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,
|
|
bool newleft, struct rb_node **leftmost,
|
|
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
|
|
/*
|
|
* Fixup the rbtree and update the augmented information when rebalancing.
|
|
*
|
|
* On insertion, the user must update the augmented information on the path
|
|
* leading to the inserted node, then call rb_link_node() as usual and
|
|
* rb_insert_augmented() instead of the usual rb_insert_color() call.
|
|
* If rb_insert_augmented() rebalances the rbtree, it will callback into
|
|
* a user provided function to update the augmented information on the
|
|
* affected subtrees.
|
|
*/
|
|
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, false, NULL, augment->rotate);
|
|
}
|
|
|
|
static inline void
|
|
rb_insert_augmented_cached(struct rb_node *node,
|
|
struct rb_root_cached *root, bool newleft,
|
|
const struct rb_augment_callbacks *augment)
|
|
{
|
|
__rb_insert_augmented(node, &root->rb_root,
|
|
newleft, &root->rb_leftmost, augment->rotate);
|
|
}
|
|
|
|
#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
|
|
rbtype, rbaugmented, rbcompute) \
|
|
static inline 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 inline 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 = { \
|
|
.propagate = rbname ## _propagate, \
|
|
.copy = rbname ## _copy, \
|
|
.rotate = rbname ## _rotate \
|
|
};
|
|
|
|
|
|
#define RB_RED 0
|
|
#define RB_BLACK 1
|
|
|
|
#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
|
|
|
|
#define __rb_color(pc) ((pc) & 1)
|
|
#define __rb_is_black(pc) __rb_color(pc)
|
|
#define __rb_is_red(pc) (!__rb_color(pc))
|
|
#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
|
|
#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
|
|
#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
|
|
|
|
static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
|
|
{
|
|
rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
|
|
}
|
|
|
|
static inline void rb_set_parent_color(struct rb_node *rb,
|
|
struct rb_node *p, int color)
|
|
{
|
|
rb->__rb_parent_color = (unsigned long)p | color;
|
|
}
|
|
|
|
static inline void
|
|
__rb_change_child(struct rb_node *old, struct rb_node *new,
|
|
struct rb_node *parent, struct rb_root *root)
|
|
{
|
|
if (parent) {
|
|
if (parent->rb_left == old)
|
|
WRITE_ONCE(parent->rb_left, new);
|
|
else
|
|
WRITE_ONCE(parent->rb_right, new);
|
|
} else
|
|
WRITE_ONCE(root->rb_node, new);
|
|
}
|
|
|
|
static inline void
|
|
__rb_change_child_rcu(struct rb_node *old, struct rb_node *new,
|
|
struct rb_node *parent, struct rb_root *root)
|
|
{
|
|
if (parent) {
|
|
if (parent->rb_left == old)
|
|
rcu_assign_pointer(parent->rb_left, new);
|
|
else
|
|
rcu_assign_pointer(parent->rb_right, new);
|
|
} else
|
|
rcu_assign_pointer(root->rb_node, new);
|
|
}
|
|
|
|
extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
|
|
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
|
|
|
|
static __always_inline struct rb_node *
|
|
__rb_erase_augmented(struct rb_node *node, struct rb_root *root,
|
|
struct rb_node **leftmost,
|
|
const struct rb_augment_callbacks *augment)
|
|
{
|
|
struct rb_node *child = node->rb_right;
|
|
struct rb_node *tmp = node->rb_left;
|
|
struct rb_node *parent, *rebalance;
|
|
unsigned long pc;
|
|
|
|
if (leftmost && node == *leftmost)
|
|
*leftmost = rb_next(node);
|
|
|
|
if (!tmp) {
|
|
/*
|
|
* Case 1: node to erase has no more than 1 child (easy!)
|
|
*
|
|
* Note that if there is one child it must be red due to 5)
|
|
* and node must be black due to 4). We adjust colors locally
|
|
* so as to bypass __rb_erase_color() later on.
|
|
*/
|
|
pc = node->__rb_parent_color;
|
|
parent = __rb_parent(pc);
|
|
__rb_change_child(node, child, parent, root);
|
|
if (child) {
|
|
child->__rb_parent_color = pc;
|
|
rebalance = NULL;
|
|
} else
|
|
rebalance = __rb_is_black(pc) ? parent : NULL;
|
|
tmp = parent;
|
|
} else if (!child) {
|
|
/* Still case 1, but this time the child is node->rb_left */
|
|
tmp->__rb_parent_color = pc = node->__rb_parent_color;
|
|
parent = __rb_parent(pc);
|
|
__rb_change_child(node, tmp, parent, root);
|
|
rebalance = NULL;
|
|
tmp = parent;
|
|
} else {
|
|
struct rb_node *successor = child, *child2;
|
|
|
|
tmp = child->rb_left;
|
|
if (!tmp) {
|
|
/*
|
|
* Case 2: node's successor is its right child
|
|
*
|
|
* (n) (s)
|
|
* / \ / \
|
|
* (x) (s) -> (x) (c)
|
|
* \
|
|
* (c)
|
|
*/
|
|
parent = successor;
|
|
child2 = successor->rb_right;
|
|
|
|
augment->copy(node, successor);
|
|
} else {
|
|
/*
|
|
* Case 3: node's successor is leftmost under
|
|
* node's right child subtree
|
|
*
|
|
* (n) (s)
|
|
* / \ / \
|
|
* (x) (y) -> (x) (y)
|
|
* / /
|
|
* (p) (p)
|
|
* / /
|
|
* (s) (c)
|
|
* \
|
|
* (c)
|
|
*/
|
|
do {
|
|
parent = successor;
|
|
successor = tmp;
|
|
tmp = tmp->rb_left;
|
|
} while (tmp);
|
|
child2 = successor->rb_right;
|
|
WRITE_ONCE(parent->rb_left, child2);
|
|
WRITE_ONCE(successor->rb_right, child);
|
|
rb_set_parent(child, successor);
|
|
|
|
augment->copy(node, successor);
|
|
augment->propagate(parent, successor);
|
|
}
|
|
|
|
tmp = node->rb_left;
|
|
WRITE_ONCE(successor->rb_left, tmp);
|
|
rb_set_parent(tmp, successor);
|
|
|
|
pc = node->__rb_parent_color;
|
|
tmp = __rb_parent(pc);
|
|
__rb_change_child(node, successor, tmp, root);
|
|
|
|
if (child2) {
|
|
successor->__rb_parent_color = pc;
|
|
rb_set_parent_color(child2, parent, RB_BLACK);
|
|
rebalance = NULL;
|
|
} else {
|
|
unsigned long pc2 = successor->__rb_parent_color;
|
|
successor->__rb_parent_color = pc;
|
|
rebalance = __rb_is_black(pc2) ? parent : NULL;
|
|
}
|
|
tmp = successor;
|
|
}
|
|
|
|
augment->propagate(tmp, NULL);
|
|
return rebalance;
|
|
}
|
|
|
|
static __always_inline void
|
|
rb_erase_augmented(struct rb_node *node, struct rb_root *root,
|
|
const struct rb_augment_callbacks *augment)
|
|
{
|
|
struct rb_node *rebalance = __rb_erase_augmented(node, root,
|
|
NULL, augment);
|
|
if (rebalance)
|
|
__rb_erase_color(rebalance, root, augment->rotate);
|
|
}
|
|
|
|
static __always_inline void
|
|
rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root,
|
|
const struct rb_augment_callbacks *augment)
|
|
{
|
|
struct rb_node *rebalance = __rb_erase_augmented(node, &root->rb_root,
|
|
&root->rb_leftmost,
|
|
augment);
|
|
if (rebalance)
|
|
__rb_erase_color(rebalance, &root->rb_root, augment->rotate);
|
|
}
|
|
|
|
#endif /* _LINUX_RBTREE_AUGMENTED_H */
|