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-rw-r--r--lib/ext2fs/rbtree.c383
1 files changed, 383 insertions, 0 deletions
diff --git a/lib/ext2fs/rbtree.c b/lib/ext2fs/rbtree.c
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+++ b/lib/ext2fs/rbtree.c
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+/*
+ 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 = ext2fs_rb_parent(node);
+
+ if ((node->rb_right = right->rb_left))
+ ext2fs_rb_set_parent(right->rb_left, node);
+ right->rb_left = node;
+
+ ext2fs_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;
+ ext2fs_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 = ext2fs_rb_parent(node);
+
+ if ((node->rb_left = left->rb_right))
+ ext2fs_rb_set_parent(left->rb_right, node);
+ left->rb_right = node;
+
+ ext2fs_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;
+ ext2fs_rb_set_parent(node, left);
+}
+
+void ext2fs_rb_insert_color(struct rb_node *node, struct rb_root *root)
+{
+ struct rb_node *parent, *gparent;
+
+ while ((parent = ext2fs_rb_parent(node)) && ext2fs_rb_is_red(parent))
+ {
+ gparent = ext2fs_rb_parent(parent);
+
+ if (parent == gparent->rb_left)
+ {
+ {
+ register struct rb_node *uncle = gparent->rb_right;
+ if (uncle && ext2fs_rb_is_red(uncle))
+ {
+ ext2fs_rb_set_black(uncle);
+ ext2fs_rb_set_black(parent);
+ ext2fs_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;
+ }
+
+ ext2fs_rb_set_black(parent);
+ ext2fs_rb_set_red(gparent);
+ __rb_rotate_right(gparent, root);
+ } else {
+ {
+ register struct rb_node *uncle = gparent->rb_left;
+ if (uncle && ext2fs_rb_is_red(uncle))
+ {
+ ext2fs_rb_set_black(uncle);
+ ext2fs_rb_set_black(parent);
+ ext2fs_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;
+ }
+
+ ext2fs_rb_set_black(parent);
+ ext2fs_rb_set_red(gparent);
+ __rb_rotate_left(gparent, root);
+ }
+ }
+
+ ext2fs_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 || ext2fs_rb_is_black(node)) && node != root->rb_node)
+ {
+ if (parent->rb_left == node)
+ {
+ other = parent->rb_right;
+ if (ext2fs_rb_is_red(other))
+ {
+ ext2fs_rb_set_black(other);
+ ext2fs_rb_set_red(parent);
+ __rb_rotate_left(parent, root);
+ other = parent->rb_right;
+ }
+ if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) &&
+ (!other->rb_right || ext2fs_rb_is_black(other->rb_right)))
+ {
+ ext2fs_rb_set_red(other);
+ node = parent;
+ parent = ext2fs_rb_parent(node);
+ }
+ else
+ {
+ if (!other->rb_right || ext2fs_rb_is_black(other->rb_right))
+ {
+ ext2fs_rb_set_black(other->rb_left);
+ ext2fs_rb_set_red(other);
+ __rb_rotate_right(other, root);
+ other = parent->rb_right;
+ }
+ ext2fs_rb_set_color(other, ext2fs_rb_color(parent));
+ ext2fs_rb_set_black(parent);
+ ext2fs_rb_set_black(other->rb_right);
+ __rb_rotate_left(parent, root);
+ node = root->rb_node;
+ break;
+ }
+ }
+ else
+ {
+ other = parent->rb_left;
+ if (ext2fs_rb_is_red(other))
+ {
+ ext2fs_rb_set_black(other);
+ ext2fs_rb_set_red(parent);
+ __rb_rotate_right(parent, root);
+ other = parent->rb_left;
+ }
+ if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) &&
+ (!other->rb_right || ext2fs_rb_is_black(other->rb_right)))
+ {
+ ext2fs_rb_set_red(other);
+ node = parent;
+ parent = ext2fs_rb_parent(node);
+ }
+ else
+ {
+ if (!other->rb_left || ext2fs_rb_is_black(other->rb_left))
+ {
+ ext2fs_rb_set_black(other->rb_right);
+ ext2fs_rb_set_red(other);
+ __rb_rotate_left(other, root);
+ other = parent->rb_left;
+ }
+ ext2fs_rb_set_color(other, ext2fs_rb_color(parent));
+ ext2fs_rb_set_black(parent);
+ ext2fs_rb_set_black(other->rb_left);
+ __rb_rotate_right(parent, root);
+ node = root->rb_node;
+ break;
+ }
+ }
+ }
+ if (node)
+ ext2fs_rb_set_black(node);
+}
+
+void ext2fs_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;
+
+ if (ext2fs_rb_parent(old)) {
+ if (ext2fs_rb_parent(old)->rb_left == old)
+ ext2fs_rb_parent(old)->rb_left = node;
+ else
+ ext2fs_rb_parent(old)->rb_right = node;
+ } else
+ root->rb_node = node;
+
+ child = node->rb_right;
+ parent = ext2fs_rb_parent(node);
+ color = ext2fs_rb_color(node);
+
+ if (parent == old) {
+ parent = node;
+ } else {
+ if (child)
+ ext2fs_rb_set_parent(child, parent);
+ parent->rb_left = child;
+
+ node->rb_right = old->rb_right;
+ ext2fs_rb_set_parent(old->rb_right, node);
+ }
+
+ node->rb_parent_color = old->rb_parent_color;
+ node->rb_left = old->rb_left;
+ ext2fs_rb_set_parent(old->rb_left, node);
+
+ goto color;
+ }
+
+ parent = ext2fs_rb_parent(node);
+ color = ext2fs_rb_color(node);
+
+ if (child)
+ ext2fs_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 *ext2fs_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;
+}
+
+struct rb_node *ext2fs_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;
+}
+
+struct rb_node *ext2fs_rb_next(struct rb_node *node)
+{
+ struct rb_node *parent;
+
+ if (ext2fs_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 = ext2fs_rb_parent(node)) && node == parent->rb_right)
+ node = parent;
+
+ return parent;
+}
+
+struct rb_node *ext2fs_rb_prev(struct rb_node *node)
+{
+ struct rb_node *parent;
+
+ if (ext2fs_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 = ext2fs_rb_parent(node)) && node == parent->rb_left)
+ node = parent;
+
+ return parent;
+}
+
+void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new,
+ struct rb_root *root)
+{
+ struct rb_node *parent = ext2fs_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)
+ ext2fs_rb_set_parent(victim->rb_left, new);
+ if (victim->rb_right)
+ ext2fs_rb_set_parent(victim->rb_right, new);
+
+ /* Copy the pointers/colour from the victim to the replacement */
+ *new = *victim;
+}
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