-/*
- 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
-
- rb_get_first and rb_get_next written by Theodore Ts'o, 9/8/2002
-*/
-
-#include <liblustre.h>
-#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;
-}
-EXPORT_SYMBOL(rb_insert_color);
-
-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);
-}
-EXPORT_SYMBOL(rb_erase);
-
-/*
- * This function returns the first node (in sort order) of the tree.
- */
-rb_node_t *rb_get_first(rb_root_t *root)
-{
- rb_node_t *n;
-
- n = root->rb_node;
- if (!n)
- return 0;
- while (n->rb_left)
- n = n->rb_left;
- return n;
-}
-EXPORT_SYMBOL(rb_get_first);
-
-/*
- * Given a node, this function will return the next node in the tree.
- */
-rb_node_t *rb_get_next(rb_node_t *n)
-{
- rb_node_t *parent;
-
- if (n->rb_right) {
- n = n->rb_right;
- while (n->rb_left)
- n = n->rb_left;
- return n;
- } else {
- while ((parent = n->rb_parent)) {
- if (n == parent->rb_left)
- return parent;
- n = parent;
- }
- return 0;
- }
-}
-EXPORT_SYMBOL(rb_get_next);
-
git://git.whamcloud.com / fs / lustre-release.git / commitdiff