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/* |
Red Black Trees |
(C) 1999 Andrea Arcangeli <andrea@suse.de> |
(C) 2002 David Woodhouse <dwmw2@infradead.org> |
(C) 2012 Michel Lespinasse <walken@google.com> |
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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. |
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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 |
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linux/include/linux/rbtree_augmented.h |
*/ |
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#ifndef _LINUX_RBTREE_AUGMENTED_H |
#define _LINUX_RBTREE_AUGMENTED_H |
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#include <linux/compiler.h> |
#include <linux/rbtree.h> |
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/* |
* 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. |
*/ |
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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); |
}; |
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extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, |
void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); |
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); |
} |
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#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 = { \ |
rbname ## _propagate, rbname ## _copy, rbname ## _rotate \ |
}; |
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#define RB_RED 0 |
#define RB_BLACK 1 |
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#define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) |
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#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) |
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static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) |
{ |
rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; |
} |
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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; |
} |
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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) |
parent->rb_left = new; |
else |
parent->rb_right = new; |
} else |
root->rb_node = new; |
} |
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extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, |
void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); |
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static __always_inline struct rb_node * |
__rb_erase_augmented(struct rb_node *node, struct rb_root *root, |
const struct rb_augment_callbacks *augment) |
{ |
struct rb_node *child = node->rb_right, *tmp = node->rb_left; |
struct rb_node *parent, *rebalance; |
unsigned long pc; |
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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); |
parent->rb_left = child2 = successor->rb_right; |
successor->rb_right = child; |
rb_set_parent(child, successor); |
augment->copy(node, successor); |
augment->propagate(parent, successor); |
} |
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successor->rb_left = tmp = node->rb_left; |
rb_set_parent(tmp, successor); |
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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; |
} |
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augment->propagate(tmp, NULL); |
return rebalance; |
} |
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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, augment); |
if (rebalance) |
__rb_erase_color(rebalance, root, augment->rotate); |
} |
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#endif /* _LINUX_RBTREE_AUGMENTED_H */ |