+++ /dev/null
-/*
- 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 "rbtree.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);
-}
-
-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))
- {
- struct rb_node *o_left;
- if ((o_left = other->rb_left))
- rb_set_black(o_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);
- if (other->rb_right)
- 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))
- {
- register struct rb_node *o_right;
- if ((o_right = other->rb_right))
- rb_set_black(o_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);
- if (other->rb_left)
- 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);
-}
-
-/*
- * This function returns the first node (in sort order) of the tree.
- */
-struct rb_node *rb_first(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;
-}
-
-struct rb_node *rb_next(const struct rb_node *node)
-{
- struct rb_node *parent;
-
- if (RB_EMPTY_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;
-}
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