/*
- Red Black Trees
- (C) 1999 Andrea Arcangeli <andrea@suse.de>
- (C) 2002 David Woodhouse <dwmw2@infradead.org>
- (C) 2012 Michel Lespinasse <walken@google.com>
-
- 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
+ * Red Black Trees
+ * Copyright (C) 1999 Andrea Arcangeli <andrea@suse.de>
+ * Copyright (C) 2002 David Woodhouse <dwmw2@infradead.org>
+ * Copyright (C) 2012 Michel Lespinasse <walken@google.com>
+ *
+ * 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
*/
#ifdef HAVE_CONFIG_H
* parentheses and have some accompanying text comment.
*/
-struct rb_augment_callbacks {
- void (*propagate)(struct rb_node *node, struct rb_node *stop);
- void (*copy)(struct rb_node *old, struct rb_node *new);
- void (*rotate)(struct rb_node *old, struct rb_node *new);
-};
-
#define RB_RED 0
#define RB_BLACK 1
-#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
+#define __rb_parent(pc) ((struct rb_node *)(pc & ~1))
#define __rb_color(pc) ((pc) & 1)
#define __rb_is_black(pc) __rb_color(pc)
#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
-static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
+static inline void
+rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
rb->__rb_parent_color = rb_color(rb) | (uintptr_t)p;
}
-static inline void rb_set_parent_color(struct rb_node *rb,
- struct rb_node *p, int color)
+static inline void
+rb_set_parent_color(struct rb_node *rb, struct rb_node *p, int color)
{
rb->__rb_parent_color = (uintptr_t)p | color;
}
-static inline void rb_set_black(struct rb_node *rb)
+static inline void
+rb_set_black(struct rb_node *rb)
{
rb->__rb_parent_color |= RB_BLACK;
}
-static inline struct rb_node *rb_red_parent(struct rb_node *red)
+static inline struct rb_node *
+rb_red_parent(struct rb_node *red)
{
return (struct rb_node *)red->__rb_parent_color;
}
static inline void
-__rb_change_child(struct rb_node *old, struct rb_node *new,
- struct rb_node *parent, struct rb_root *root)
+rb_change_child(struct rb_node *old, struct rb_node *new,
+ struct rb_node *parent, struct rb_root *root)
{
if (parent) {
if (parent->rb_left == old)
* - old gets assigned new as a parent and 'color' as a color.
*/
static inline void
-__rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
+rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
struct rb_root *root, int color)
{
struct rb_node *parent = rb_parent(old);
new->__rb_parent_color = old->__rb_parent_color;
rb_set_parent_color(old, new, color);
- __rb_change_child(old, new, parent, root);
+ rb_change_child(old, new, parent, root);
}
-static inline void
-__rb_erase_color(struct rb_node *parent, struct rb_root *root,
- void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+static void
+rb_erase_color(struct rb_node *parent, struct rb_root *root)
{
struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
- while (true) {
+ for (;;) {
/*
* Loop invariants:
* - node is black (or NULL on first iteration)
parent->rb_right = tmp1 = sibling->rb_left;
sibling->rb_left = parent;
rb_set_parent_color(tmp1, parent, RB_BLACK);
- __rb_rotate_set_parents(parent, sibling, root,
- RB_RED);
- augment_rotate(parent, sibling);
+ rb_rotate_set_parents(parent, sibling, root, RB_RED);
sibling = tmp1;
}
tmp1 = sibling->rb_right;
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
- augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
rb_set_parent_color(tmp1, sibling, RB_BLACK);
if (tmp2)
rb_set_parent(tmp2, parent);
- __rb_rotate_set_parents(parent, sibling, root,
- RB_BLACK);
- augment_rotate(parent, sibling);
+ rb_rotate_set_parents(parent, sibling, root, RB_BLACK);
break;
} else {
sibling = parent->rb_left;
parent->rb_left = tmp1 = sibling->rb_right;
sibling->rb_right = parent;
rb_set_parent_color(tmp1, parent, RB_BLACK);
- __rb_rotate_set_parents(parent, sibling, root,
- RB_RED);
- augment_rotate(parent, sibling);
+ rb_rotate_set_parents(parent, sibling, root,
+ RB_RED);
sibling = tmp1;
}
tmp1 = sibling->rb_left;
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
- augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
rb_set_parent_color(tmp1, sibling, RB_BLACK);
if (tmp2)
rb_set_parent(tmp2, parent);
- __rb_rotate_set_parents(parent, sibling, root,
- RB_BLACK);
- augment_rotate(parent, sibling);
+ rb_rotate_set_parents(parent, sibling, root, RB_BLACK);
break;
}
}
}
-static inline void
-rb_erase_augmented(struct rb_node *node, struct rb_root *root,
- const struct rb_augment_callbacks *augment)
+void
+rb_erase(struct rb_node *node, struct rb_root *root)
{
struct rb_node *child = node->rb_right, *tmp = node->rb_left;
struct rb_node *parent, *rebalance;
*/
pc = node->__rb_parent_color;
parent = __rb_parent(pc);
- __rb_change_child(node, child, parent, root);
+ rb_change_child(node, child, parent, root);
if (child) {
child->__rb_parent_color = pc;
rebalance = NULL;
/* Still case 1, but this time the child is node->rb_left */
tmp->__rb_parent_color = pc = node->__rb_parent_color;
parent = __rb_parent(pc);
- __rb_change_child(node, tmp, parent, root);
+ rb_change_child(node, tmp, parent, root);
rebalance = NULL;
tmp = parent;
} else {
*/
parent = successor;
child2 = successor->rb_right;
- augment->copy(node, successor);
} else {
/*
* Case 3: node's successor is leftmost under
parent->rb_left = child2 = successor->rb_right;
successor->rb_right = child;
rb_set_parent(child, successor);
- augment->copy(node, successor);
- augment->propagate(parent, successor);
}
successor->rb_left = tmp = node->rb_left;
pc = node->__rb_parent_color;
tmp = __rb_parent(pc);
- __rb_change_child(node, successor, tmp, root);
+ rb_change_child(node, successor, tmp, root);
if (child2) {
successor->__rb_parent_color = pc;
rb_set_parent_color(child2, parent, RB_BLACK);
tmp = successor;
}
- augment->propagate(tmp, NULL);
if (rebalance)
- __rb_erase_color(rebalance, root, augment->rotate);
+ rb_erase_color(rebalance, root);
}
-
-static inline void
-__rb_insert(struct rb_node *node, struct rb_root *root,
- void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+void
+rb_insert_color(struct rb_node *node, struct rb_root *root)
{
struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
rb_set_parent_color(tmp, parent,
RB_BLACK);
rb_set_parent_color(parent, node, RB_RED);
- augment_rotate(parent, node);
parent = node;
tmp = node->rb_right;
}
parent->rb_right = gparent;
if (tmp)
rb_set_parent_color(tmp, gparent, RB_BLACK);
- __rb_rotate_set_parents(gparent, parent, root, RB_RED);
- augment_rotate(gparent, parent);
+ rb_rotate_set_parents(gparent, parent, root, RB_RED);
break;
} else {
tmp = gparent->rb_left;
rb_set_parent_color(tmp, parent,
RB_BLACK);
rb_set_parent_color(parent, node, RB_RED);
- augment_rotate(parent, node);
parent = node;
tmp = node->rb_left;
}
parent->rb_left = gparent;
if (tmp)
rb_set_parent_color(tmp, gparent, RB_BLACK);
- __rb_rotate_set_parents(gparent, parent, root, RB_RED);
- augment_rotate(gparent, parent);
+ rb_rotate_set_parents(gparent, parent, root, RB_RED);
break;
}
}
}
+static struct rb_node *
+rb_left_deepest_node(const struct rb_node *node)
+{
+ for (;;) {
+ if (node->rb_left)
+ node = node->rb_left;
+ else if (node->rb_right)
+ node = node->rb_right;
+ else
+ return (struct rb_node *)node;
+ }
+}
-/*
- * Non-augmented rbtree manipulation functions.
- *
- * We use dummy augmented callbacks here, and have the compiler optimize them
- * out of the rb_insert_color() and rb_erase() function definitions.
- */
+struct rb_node *
+rb_next_postorder(const struct rb_node *node, const struct rb_node *parent)
+{
+ /* If we're sitting on node, we've already seen our children */
+ if (parent && node == parent->rb_left && parent->rb_right) {
+ /* If we are the parent's left node, go to the parent's right
+ * node then all the way down to the left */
+ return rb_left_deepest_node(parent->rb_right);
+ } else
+ /* Otherwise we are the parent's right node, and the parent
+ * should be next */
+ return (struct rb_node *)parent;
+}
-static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
-static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {}
-static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {}
+struct rb_node *
+rb_first_postorder(const struct rb_root *root)
+{
+ if (!root->rb_node)
+ return NULL;
-static const struct rb_augment_callbacks dummy_callbacks = {
- dummy_propagate, dummy_copy, dummy_rotate
-};
+ return rb_left_deepest_node(root->rb_node);
+}
-void rb_insert_color(struct rb_node *node, struct rb_root *root)
+struct rb_node *
+rb_next(const struct rb_node *node)
{
- __rb_insert(node, root, dummy_rotate);
+ struct rb_node *parent;
+
+ /*
+ * 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;
}
-void rb_erase(struct rb_node *node, struct rb_root *root)
+/*
+ * This function returns the first node (in sort order) of the tree.
+ */
+struct rb_node *
+rb_first(const struct rb_root *root)
{
- rb_erase_augmented(node, root, &dummy_callbacks);
+ struct rb_node *n;
+
+ n = root->rb_node;
+ if (!n)
+ return NULL;
+ while (n->rb_left)
+ n = n->rb_left;
+ return n;
}
git://wimlib.net / wimlib / blobdiff