patch-2.4.10 linux/lib/rbtree.c

• Lines: 294
• Date: Mon Sep 17 15:30:23 2001
• Orig file: v2.4.9/linux/lib/rbtree.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/lib/rbtree.c linux/lib/rbtree.c
@@ -0,0 +1,293 @@
+/*
+  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/lib/rbtree.c
+*/
+
+#include <linux/rbtree.h>
+
+static void __rb_rotate_left(rb_node_t * node, rb_root_t * root)
+{
+	rb_node_t * right = node->rb_right;
+
+	if ((node->rb_right = right->rb_left))
+		right->rb_left->rb_parent = node;
+	right->rb_left = node;
+
+	if ((right->rb_parent = node->rb_parent))
+	{
+		if (node == node->rb_parent->rb_left)
+			node->rb_parent->rb_left = right;
+		else
+			node->rb_parent->rb_right = right;
+	}
+	else
+		root->rb_node = right;
+	node->rb_parent = right;
+}
+
+static void __rb_rotate_right(rb_node_t * node, rb_root_t * root)
+{
+	rb_node_t * left = node->rb_left;
+
+	if ((node->rb_left = left->rb_right))
+		left->rb_right->rb_parent = node;
+	left->rb_right = node;
+
+	if ((left->rb_parent = node->rb_parent))
+	{
+		if (node == node->rb_parent->rb_right)
+			node->rb_parent->rb_right = left;
+		else
+			node->rb_parent->rb_left = left;
+	}
+	else
+		root->rb_node = left;
+	node->rb_parent = left;
+}
+
+void rb_insert_color(rb_node_t * node, rb_root_t * root)
+{
+	rb_node_t * parent, * gparent;
+
+	while ((parent = node->rb_parent) && parent->rb_color == RB_RED)
+	{
+		gparent = parent->rb_parent;
+
+		if (parent == gparent->rb_left)
+		{
+			{
+				register rb_node_t * uncle = gparent->rb_right;
+				if (uncle && uncle->rb_color == RB_RED)
+				{
+					uncle->rb_color = RB_BLACK;
+					parent->rb_color = RB_BLACK;
+					gparent->rb_color = RB_RED;
+					node = gparent;
+					continue;
+				}
+			}
+
+			if (parent->rb_right == node)
+			{
+				register rb_node_t * tmp;
+				__rb_rotate_left(parent, root);
+				tmp = parent;
+				parent = node;
+				node = tmp;
+			}
+
+			parent->rb_color = RB_BLACK;
+			gparent->rb_color = RB_RED;
+			__rb_rotate_right(gparent, root);
+		} else {
+			{
+				register rb_node_t * uncle = gparent->rb_left;
+				if (uncle && uncle->rb_color == RB_RED)
+				{
+					uncle->rb_color = RB_BLACK;
+					parent->rb_color = RB_BLACK;
+					gparent->rb_color = RB_RED;
+					node = gparent;
+					continue;
+				}
+			}
+
+			if (parent->rb_left == node)
+			{
+				register rb_node_t * tmp;
+				__rb_rotate_right(parent, root);
+				tmp = parent;
+				parent = node;
+				node = tmp;
+			}
+
+			parent->rb_color = RB_BLACK;
+			gparent->rb_color = RB_RED;
+			__rb_rotate_left(gparent, root);
+		}
+	}
+
+	root->rb_node->rb_color = RB_BLACK;
+}
+
+static void __rb_erase_color(rb_node_t * node, rb_node_t * parent,
+			     rb_root_t * root)
+{
+	rb_node_t * other;
+
+	while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)
+	{
+		if (parent->rb_left == node)
+		{
+			other = parent->rb_right;
+			if (other->rb_color == RB_RED)
+			{
+				other->rb_color = RB_BLACK;
+				parent->rb_color = RB_RED;
+				__rb_rotate_left(parent, root);
+				other = parent->rb_right;
+			}
+			if ((!other->rb_left ||
+			     other->rb_left->rb_color == RB_BLACK)
+			    && (!other->rb_right ||
+				other->rb_right->rb_color == RB_BLACK))
+			{
+				other->rb_color = RB_RED;
+				node = parent;
+				parent = node->rb_parent;
+			}
+			else
+			{
+				if (!other->rb_right ||
+				    other->rb_right->rb_color == RB_BLACK)
+				{
+					register rb_node_t * o_left;
+					if ((o_left = other->rb_left))
+						o_left->rb_color = RB_BLACK;
+					other->rb_color = RB_RED;
+					__rb_rotate_right(other, root);
+					other = parent->rb_right;
+				}
+				other->rb_color = parent->rb_color;
+				parent->rb_color = RB_BLACK;
+				if (other->rb_right)
+					other->rb_right->rb_color = RB_BLACK;
+				__rb_rotate_left(parent, root);
+				node = root->rb_node;
+				break;
+			}
+		}
+		else
+		{
+			other = parent->rb_left;
+			if (other->rb_color == RB_RED)
+			{
+				other->rb_color = RB_BLACK;
+				parent->rb_color = RB_RED;
+				__rb_rotate_right(parent, root);
+				other = parent->rb_left;
+			}
+			if ((!other->rb_left ||
+			     other->rb_left->rb_color == RB_BLACK)
+			    && (!other->rb_right ||
+				other->rb_right->rb_color == RB_BLACK))
+			{
+				other->rb_color = RB_RED;
+				node = parent;
+				parent = node->rb_parent;
+			}
+			else
+			{
+				if (!other->rb_left ||
+				    other->rb_left->rb_color == RB_BLACK)
+				{
+					register rb_node_t * o_right;
+					if ((o_right = other->rb_right))
+						o_right->rb_color = RB_BLACK;
+					other->rb_color = RB_RED;
+					__rb_rotate_left(other, root);
+					other = parent->rb_left;
+				}
+				other->rb_color = parent->rb_color;
+				parent->rb_color = RB_BLACK;
+				if (other->rb_left)
+					other->rb_left->rb_color = RB_BLACK;
+				__rb_rotate_right(parent, root);
+				node = root->rb_node;
+				break;
+			}
+		}
+	}
+	if (node)
+		node->rb_color = RB_BLACK;
+}
+
+void rb_erase(rb_node_t * node, rb_root_t * root)
+{
+	rb_node_t * child, * parent;
+	int color;
+
+	if (!node->rb_left)
+		child = node->rb_right;
+	else if (!node->rb_right)
+		child = node->rb_left;
+	else
+	{
+		rb_node_t * old = node, * left;
+
+		node = node->rb_right;
+		while ((left = node->rb_left))
+			node = left;
+		child = node->rb_right;
+		parent = node->rb_parent;
+		color = node->rb_color;
+
+		if (child)
+			child->rb_parent = parent;
+		if (parent)
+		{
+			if (parent->rb_left == node)
+				parent->rb_left = child;
+			else
+				parent->rb_right = child;
+		}
+		else
+			root->rb_node = child;
+
+		if (node->rb_parent == old)
+			parent = node;
+		node->rb_parent = old->rb_parent;
+		node->rb_color = old->rb_color;
+		node->rb_right = old->rb_right;
+		node->rb_left = old->rb_left;
+
+		if (old->rb_parent)
+		{
+			if (old->rb_parent->rb_left == old)
+				old->rb_parent->rb_left = node;
+			else
+				old->rb_parent->rb_right = node;
+		} else
+			root->rb_node = node;
+
+		old->rb_left->rb_parent = node;
+		if (old->rb_right)
+			old->rb_right->rb_parent = node;
+		goto color;
+	}
+
+	parent = node->rb_parent;
+	color = node->rb_color;
+
+	if (child)
+		child->rb_parent = 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);
+}