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/*
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);
}
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