lib/rbtree.c - linux-mtk - Git at Google

 /*
   Red Black Trees
   (C) 1999  Andrea Arcangeli <andrea@suse.de>
   (C) 2002  David Woodhouse <dwmw2@infradead.org>

   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/lib/rbtree.c
 */

 #include <linux/rbtree.h>
 #include <linux/module.h>

 static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
 {
 	struct rb_node *right = node->rb_right;
 	struct rb_node *parent = rb_parent(node);

 	if ((node->rb_right = right->rb_left))
 		rb_set_parent(right->rb_left, node);
 	right->rb_left = node;

 	rb_set_parent(right, parent);

 	if (parent)
 	{
 		if (node == parent->rb_left)
 			parent->rb_left = right;
 		else
 			parent->rb_right = right;
 	}
 	else
 		root->rb_node = right;
 	rb_set_parent(node, right);
 }

 static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
 {
 	struct rb_node *left = node->rb_left;
 	struct rb_node *parent = rb_parent(node);

 	if ((node->rb_left = left->rb_right))
 		rb_set_parent(left->rb_right, node);
 	left->rb_right = node;

 	rb_set_parent(left, parent);

 	if (parent)
 	{
 		if (node == parent->rb_right)
 			parent->rb_right = left;
 		else
 			parent->rb_left = left;
 	}
 	else
 		root->rb_node = left;
 	rb_set_parent(node, left);
 }

 void rb_insert_color(struct rb_node *node, struct rb_root *root)
 {
 	struct rb_node *parent, *gparent;

 	while ((parent = rb_parent(node)) && rb_is_red(parent))
 	{
 		gparent = rb_parent(parent);

 		if (parent == gparent->rb_left)
 		{
 			{
 				register struct rb_node *uncle = gparent->rb_right;
 				if (uncle && rb_is_red(uncle))
 				{
 					rb_set_black(uncle);
 					rb_set_black(parent);
 					rb_set_red(gparent);
 					node = gparent;
 					continue;
 				}
 			}

 			if (parent->rb_right == node)
 			{
 				register struct rb_node *tmp;
 				__rb_rotate_left(parent, root);
 				tmp = parent;
 				parent = node;
 				node = tmp;
 			}

 			rb_set_black(parent);
 			rb_set_red(gparent);
 			__rb_rotate_right(gparent, root);
 		} else {
 			{
 				register struct rb_node *uncle = gparent->rb_left;
 				if (uncle && rb_is_red(uncle))
 				{
 					rb_set_black(uncle);
 					rb_set_black(parent);
 					rb_set_red(gparent);
 					node = gparent;
 					continue;
 				}
 			}

 			if (parent->rb_left == node)
 			{
 				register struct rb_node *tmp;
 				__rb_rotate_right(parent, root);
 				tmp = parent;
 				parent = node;
 				node = tmp;
 			}

 			rb_set_black(parent);
 			rb_set_red(gparent);
 			__rb_rotate_left(gparent, root);
 		}
 	}

 	rb_set_black(root->rb_node);
 }
 EXPORT_SYMBOL(rb_insert_color);

 static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
 			     struct rb_root *root)
 {
 	struct rb_node *other;

 	while ((!node || rb_is_black(node)) && node != root->rb_node)
 	{
 		if (parent->rb_left == node)
 		{
 			other = parent->rb_right;
 			if (rb_is_red(other))
 			{
 				rb_set_black(other);
 				rb_set_red(parent);
 				__rb_rotate_left(parent, root);
 				other = parent->rb_right;
 			}
 			if ((!other->rb_left || rb_is_black(other->rb_left)) &&
 			    (!other->rb_right || rb_is_black(other->rb_right)))
 			{
 				rb_set_red(other);
 				node = parent;
 				parent = rb_parent(node);
 			}
 			else
 			{
 				if (!other->rb_right || rb_is_black(other->rb_right))
 				{
 					rb_set_black(other->rb_left);
 					rb_set_red(other);
 					__rb_rotate_right(other, root);
 					other = parent->rb_right;
 				}
 				rb_set_color(other, rb_color(parent));
 				rb_set_black(parent);
 				rb_set_black(other->rb_right);
 				__rb_rotate_left(parent, root);
 				node = root->rb_node;
 				break;
 			}
 		}
 		else
 		{
 			other = parent->rb_left;
 			if (rb_is_red(other))
 			{
 				rb_set_black(other);
 				rb_set_red(parent);
 				__rb_rotate_right(parent, root);
 				other = parent->rb_left;
 			}
 			if ((!other->rb_left || rb_is_black(other->rb_left)) &&
 			    (!other->rb_right || rb_is_black(other->rb_right)))
 			{
 				rb_set_red(other);
 				node = parent;
 				parent = rb_parent(node);
 			}
 			else
 			{
 				if (!other->rb_left || rb_is_black(other->rb_left))
 				{
 					rb_set_black(other->rb_right);
 					rb_set_red(other);
 					__rb_rotate_left(other, root);
 					other = parent->rb_left;
 				}
 				rb_set_color(other, rb_color(parent));
 				rb_set_black(parent);
 				rb_set_black(other->rb_left);
 				__rb_rotate_right(parent, root);
 				node = root->rb_node;
 				break;
 			}
 		}
 	}
 	if (node)
 		rb_set_black(node);
 }

 void rb_erase(struct rb_node *node, struct rb_root *root)
 {
 	struct rb_node *child, *parent;
 	int color;

 	if (!node->rb_left)
 		child = node->rb_right;
 	else if (!node->rb_right)
 		child = node->rb_left;
 	else
 	{
 		struct rb_node *old = node, *left;

 		node = node->rb_right;
 		while ((left = node->rb_left) != NULL)
 			node = left;
 		child = node->rb_right;
 		parent = rb_parent(node);
 		color = rb_color(node);

 		if (child)
 			rb_set_parent(child, parent);
 		if (parent == old) {
 			parent->rb_right = child;
 			parent = node;
 		} else
 			parent->rb_left = child;

 		node->rb_parent_color = old->rb_parent_color;
 		node->rb_right = old->rb_right;
 		node->rb_left = old->rb_left;

 		if (rb_parent(old))
 		{
 			if (rb_parent(old)->rb_left == old)
 				rb_parent(old)->rb_left = node;
 			else
 				rb_parent(old)->rb_right = node;
 		} else
 			root->rb_node = node;

 		rb_set_parent(old->rb_left, node);
 		if (old->rb_right)
 			rb_set_parent(old->rb_right, node);
 		goto color;
 	}

 	parent = rb_parent(node);
 	color = rb_color(node);

 	if (child)
 		rb_set_parent(child, parent);
 	if (parent)
 	{
 		if (parent->rb_left == node)
 			parent->rb_left = child;
 		else
 			parent->rb_right = child;
 	}
 	else
 		root->rb_node = child;

  color:
 	if (color == RB_BLACK)
 		__rb_erase_color(child, parent, root);
 }
 EXPORT_SYMBOL(rb_erase);

 /*
  * This function returns the first node (in sort order) of the tree.
  */
 struct rb_node *rb_first(const struct rb_root *root)
 {
 	struct rb_node	*n;

 	n = root->rb_node;
 	if (!n)
 		return NULL;
 	while (n->rb_left)
 		n = n->rb_left;
 	return n;
 }
 EXPORT_SYMBOL(rb_first);

 struct rb_node *rb_last(const struct rb_root *root)
 {
 	struct rb_node	*n;

 	n = root->rb_node;
 	if (!n)
 		return NULL;
 	while (n->rb_right)
 		n = n->rb_right;
 	return n;
 }
 EXPORT_SYMBOL(rb_last);

 struct rb_node *rb_next(const struct rb_node *node)
 {
 	struct rb_node *parent;

 	if (rb_parent(node) == node)
 		return NULL;

 	/* If we have a right-hand child, go down and then left as far
 	   as we can. */
 	if (node->rb_right) {
 		node = node->rb_right;
 		while (node->rb_left)
 			node=node->rb_left;
 		return (struct rb_node *)node;
 	}

 	/* No right-hand children.  Everything down and left is
 	   smaller than us, so any 'next' node must be in the general
 	   direction of our parent. Go up the tree; any time the
 	   ancestor is a right-hand child of its parent, keep going
 	   up. First time it's a left-hand child of its parent, said
 	   parent is our 'next' node. */
 	while ((parent = rb_parent(node)) && node == parent->rb_right)
 		node = parent;

 	return parent;
 }
 EXPORT_SYMBOL(rb_next);

 struct rb_node *rb_prev(const struct rb_node *node)
 {
 	struct rb_node *parent;

 	if (rb_parent(node) == node)
 		return NULL;

 	/* If we have a left-hand child, go down and then right as far
 	   as we can. */
 	if (node->rb_left) {
 		node = node->rb_left;
 		while (node->rb_right)
 			node=node->rb_right;
 		return (struct rb_node *)node;
 	}

 	/* No left-hand children. Go up till we find an ancestor which
 	   is a right-hand child of its parent */
 	while ((parent = rb_parent(node)) && node == parent->rb_left)
 		node = parent;

 	return parent;
 }
 EXPORT_SYMBOL(rb_prev);

 void rb_replace_node(struct rb_node *victim, struct rb_node *new,
 		     struct rb_root *root)
 {
 	struct rb_node *parent = rb_parent(victim);

 	/* Set the surrounding nodes to point to the replacement */
 	if (parent) {
 		if (victim == parent->rb_left)
 			parent->rb_left = new;
 		else
 			parent->rb_right = new;
 	} else {
 		root->rb_node = new;
 	}
 	if (victim->rb_left)
 		rb_set_parent(victim->rb_left, new);
 	if (victim->rb_right)
 		rb_set_parent(victim->rb_right, new);

 	/* Copy the pointers/colour from the victim to the replacement */
 	*new = *victim;
 }
 EXPORT_SYMBOL(rb_replace_node);
	/*
	Red Black Trees
	(C) 1999 Andrea Arcangeli <andrea@suse.de>
	(C) 2002 David Woodhouse <dwmw2@infradead.org>

	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/lib/rbtree.c
	*/

	#include <linux/rbtree.h>
	#include <linux/module.h>

	static void __rb_rotate_left(struct rb_node node, struct rb_root root)
	{
	struct rb_node *right = node->rb_right;
	struct rb_node *parent = rb_parent(node);

	if ((node->rb_right = right->rb_left))
	rb_set_parent(right->rb_left, node);
	right->rb_left = node;

	rb_set_parent(right, parent);

	if (parent)
	{
	if (node == parent->rb_left)
	parent->rb_left = right;
	else
	parent->rb_right = right;
	}
	else
	root->rb_node = right;
	rb_set_parent(node, right);
	}

	static void __rb_rotate_right(struct rb_node node, struct rb_root root)
	{
	struct rb_node *left = node->rb_left;
	struct rb_node *parent = rb_parent(node);

	if ((node->rb_left = left->rb_right))
	rb_set_parent(left->rb_right, node);
	left->rb_right = node;

	rb_set_parent(left, parent);

	if (parent)
	{
	if (node == parent->rb_right)
	parent->rb_right = left;
	else
	parent->rb_left = left;
	}
	else
	root->rb_node = left;
	rb_set_parent(node, left);
	}

	void rb_insert_color(struct rb_node node, struct rb_root root)
	{
	struct rb_node parent, gparent;

	while ((parent = rb_parent(node)) && rb_is_red(parent))
	{
	gparent = rb_parent(parent);

	if (parent == gparent->rb_left)
	{
	{
	register struct rb_node *uncle = gparent->rb_right;
	if (uncle && rb_is_red(uncle))
	{
	rb_set_black(uncle);
	rb_set_black(parent);
	rb_set_red(gparent);
	node = gparent;
	continue;
	}
	}

	if (parent->rb_right == node)
	{
	register struct rb_node *tmp;
	__rb_rotate_left(parent, root);
	tmp = parent;
	parent = node;
	node = tmp;
	}

	rb_set_black(parent);
	rb_set_red(gparent);
	__rb_rotate_right(gparent, root);
	} else {
	{
	register struct rb_node *uncle = gparent->rb_left;
	if (uncle && rb_is_red(uncle))
	{
	rb_set_black(uncle);
	rb_set_black(parent);
	rb_set_red(gparent);
	node = gparent;
	continue;
	}
	}

	if (parent->rb_left == node)
	{
	register struct rb_node *tmp;
	__rb_rotate_right(parent, root);
	tmp = parent;
	parent = node;
	node = tmp;
	}

	rb_set_black(parent);
	rb_set_red(gparent);
	__rb_rotate_left(gparent, root);
	}
	}

	rb_set_black(root->rb_node);
	}
	EXPORT_SYMBOL(rb_insert_color);

	static void __rb_erase_color(struct rb_node node, struct rb_node parent,
	struct rb_root *root)
	{
	struct rb_node *other;

	while ((!node \|\| rb_is_black(node)) && node != root->rb_node)
	{
	if (parent->rb_left == node)
	{
	other = parent->rb_right;
	if (rb_is_red(other))
	{
	rb_set_black(other);
	rb_set_red(parent);
	__rb_rotate_left(parent, root);
	other = parent->rb_right;
	}
	if ((!other->rb_left \|\| rb_is_black(other->rb_left)) &&
	(!other->rb_right \|\| rb_is_black(other->rb_right)))
	{
	rb_set_red(other);
	node = parent;
	parent = rb_parent(node);
	}
	else
	{
	if (!other->rb_right \|\| rb_is_black(other->rb_right))
	{
	rb_set_black(other->rb_left);
	rb_set_red(other);
	__rb_rotate_right(other, root);
	other = parent->rb_right;
	}
	rb_set_color(other, rb_color(parent));
	rb_set_black(parent);
	rb_set_black(other->rb_right);
	__rb_rotate_left(parent, root);
	node = root->rb_node;
	break;
	}
	}
	else
	{
	other = parent->rb_left;
	if (rb_is_red(other))
	{
	rb_set_black(other);
	rb_set_red(parent);
	__rb_rotate_right(parent, root);
	other = parent->rb_left;
	}
	if ((!other->rb_left \|\| rb_is_black(other->rb_left)) &&
	(!other->rb_right \|\| rb_is_black(other->rb_right)))
	{
	rb_set_red(other);
	node = parent;
	parent = rb_parent(node);
	}
	else
	{
	if (!other->rb_left \|\| rb_is_black(other->rb_left))
	{
	rb_set_black(other->rb_right);
	rb_set_red(other);
	__rb_rotate_left(other, root);
	other = parent->rb_left;
	}
	rb_set_color(other, rb_color(parent));
	rb_set_black(parent);
	rb_set_black(other->rb_left);
	__rb_rotate_right(parent, root);
	node = root->rb_node;
	break;
	}
	}
	}
	if (node)
	rb_set_black(node);
	}

	void rb_erase(struct rb_node node, struct rb_root root)
	{
	struct rb_node child, parent;
	int color;

	if (!node->rb_left)
	child = node->rb_right;
	else if (!node->rb_right)
	child = node->rb_left;
	else
	{
	struct rb_node old = node, left;

	node = node->rb_right;
	while ((left = node->rb_left) != NULL)
	node = left;
	child = node->rb_right;
	parent = rb_parent(node);
	color = rb_color(node);

	if (child)
	rb_set_parent(child, parent);
	if (parent == old) {
	parent->rb_right = child;
	parent = node;
	} else
	parent->rb_left = child;

	node->rb_parent_color = old->rb_parent_color;
	node->rb_right = old->rb_right;
	node->rb_left = old->rb_left;

	if (rb_parent(old))
	{
	if (rb_parent(old)->rb_left == old)
	rb_parent(old)->rb_left = node;
	else
	rb_parent(old)->rb_right = node;
	} else
	root->rb_node = node;

	rb_set_parent(old->rb_left, node);
	if (old->rb_right)
	rb_set_parent(old->rb_right, node);
	goto color;
	}

	parent = rb_parent(node);
	color = rb_color(node);

	if (child)
	rb_set_parent(child, parent);
	if (parent)
	{
	if (parent->rb_left == node)
	parent->rb_left = child;
	else
	parent->rb_right = child;
	}
	else
	root->rb_node = child;

	color:
	if (color == RB_BLACK)
	__rb_erase_color(child, parent, root);
	}
	EXPORT_SYMBOL(rb_erase);

	/*
	* This function returns the first node (in sort order) of the tree.
	*/
	struct rb_node rb_first(const struct rb_root root)
	{
	struct rb_node *n;

	n = root->rb_node;
	if (!n)
	return NULL;
	while (n->rb_left)
	n = n->rb_left;
	return n;
	}
	EXPORT_SYMBOL(rb_first);

	struct rb_node rb_last(const struct rb_root root)
	{
	struct rb_node *n;

	n = root->rb_node;
	if (!n)
	return NULL;
	while (n->rb_right)
	n = n->rb_right;
	return n;
	}
	EXPORT_SYMBOL(rb_last);

	struct rb_node rb_next(const struct rb_node node)
	{
	struct rb_node *parent;

	if (rb_parent(node) == node)
	return NULL;

	/* If we have a right-hand child, go down and then left as far
	as we can. */
	if (node->rb_right) {
	node = node->rb_right;
	while (node->rb_left)
	node=node->rb_left;
	return (struct rb_node *)node;
	}

	/* No right-hand children. Everything down and left is
	smaller than us, so any 'next' node must be in the general
	direction of our parent. Go up the tree; any time the
	ancestor is a right-hand child of its parent, keep going
	up. First time it's a left-hand child of its parent, said
	parent is our 'next' node. */
	while ((parent = rb_parent(node)) && node == parent->rb_right)
	node = parent;

	return parent;
	}
	EXPORT_SYMBOL(rb_next);

	struct rb_node rb_prev(const struct rb_node node)
	{
	struct rb_node *parent;

	if (rb_parent(node) == node)
	return NULL;

	/* If we have a left-hand child, go down and then right as far
	as we can. */
	if (node->rb_left) {
	node = node->rb_left;
	while (node->rb_right)
	node=node->rb_right;
	return (struct rb_node *)node;
	}

	/* No left-hand children. Go up till we find an ancestor which
	is a right-hand child of its parent */
	while ((parent = rb_parent(node)) && node == parent->rb_left)
	node = parent;

	return parent;
	}
	EXPORT_SYMBOL(rb_prev);

	void rb_replace_node(struct rb_node victim, struct rb_node new,
	struct rb_root *root)
	{
	struct rb_node *parent = rb_parent(victim);

	/* Set the surrounding nodes to point to the replacement */
	if (parent) {
	if (victim == parent->rb_left)
	parent->rb_left = new;
	else
	parent->rb_right = new;
	} else {
	root->rb_node = new;
	}
	if (victim->rb_left)
	rb_set_parent(victim->rb_left, new);
	if (victim->rb_right)
	rb_set_parent(victim->rb_right, new);

	/* Copy the pointers/colour from the victim to the replacement */
	new = victim;
	}
	EXPORT_SYMBOL(rb_replace_node);