rbtree: Undo augmented trees performance damage and regression
[linux-2.6.git] / lib / rbtree.c
index 14b791a..4693f79 100644 (file)
 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))
-               right->rb_left->rb_parent = node;
+               rb_set_parent(right->rb_left, node);
        right->rb_left = node;
 
-       if ((right->rb_parent = node->rb_parent))
+       rb_set_parent(right, parent);
+
+       if (parent)
        {
-               if (node == node->rb_parent->rb_left)
-                       node->rb_parent->rb_left = right;
+               if (node == parent->rb_left)
+                       parent->rb_left = right;
                else
-                       node->rb_parent->rb_right = right;
+                       parent->rb_right = right;
        }
        else
                root->rb_node = right;
-       node->rb_parent = 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))
-               left->rb_right->rb_parent = node;
+               rb_set_parent(left->rb_right, node);
        left->rb_right = node;
 
-       if ((left->rb_parent = node->rb_parent))
+       rb_set_parent(left, parent);
+
+       if (parent)
        {
-               if (node == node->rb_parent->rb_right)
-                       node->rb_parent->rb_right = left;
+               if (node == parent->rb_right)
+                       parent->rb_right = left;
                else
-                       node->rb_parent->rb_left = left;
+                       parent->rb_left = left;
        }
        else
                root->rb_node = left;
-       node->rb_parent = 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 = node->rb_parent) && parent->rb_color == RB_RED)
+       while ((parent = rb_parent(node)) && rb_is_red(parent))
        {
-               gparent = parent->rb_parent;
+               gparent = rb_parent(parent);
 
                if (parent == gparent->rb_left)
                {
                        {
                                register struct rb_node *uncle = gparent->rb_right;
-                               if (uncle && uncle->rb_color == RB_RED)
+                               if (uncle && rb_is_red(uncle))
                                {
-                                       uncle->rb_color = RB_BLACK;
-                                       parent->rb_color = RB_BLACK;
-                                       gparent->rb_color = RB_RED;
+                                       rb_set_black(uncle);
+                                       rb_set_black(parent);
+                                       rb_set_red(gparent);
                                        node = gparent;
                                        continue;
                                }
@@ -94,17 +100,17 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
                                node = tmp;
                        }
 
-                       parent->rb_color = RB_BLACK;
-                       gparent->rb_color = RB_RED;
+                       rb_set_black(parent);
+                       rb_set_red(gparent);
                        __rb_rotate_right(gparent, root);
                } else {
                        {
                                register struct rb_node *uncle = gparent->rb_left;
-                               if (uncle && uncle->rb_color == RB_RED)
+                               if (uncle && rb_is_red(uncle))
                                {
-                                       uncle->rb_color = RB_BLACK;
-                                       parent->rb_color = RB_BLACK;
-                                       gparent->rb_color = RB_RED;
+                                       rb_set_black(uncle);
+                                       rb_set_black(parent);
+                                       rb_set_red(gparent);
                                        node = gparent;
                                        continue;
                                }
@@ -119,13 +125,13 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
                                node = tmp;
                        }
 
-                       parent->rb_color = RB_BLACK;
-                       gparent->rb_color = RB_RED;
+                       rb_set_black(parent);
+                       rb_set_red(gparent);
                        __rb_rotate_left(gparent, root);
                }
        }
 
-       root->rb_node->rb_color = RB_BLACK;
+       rb_set_black(root->rb_node);
 }
 EXPORT_SYMBOL(rb_insert_color);
 
@@ -134,43 +140,37 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
 {
        struct rb_node *other;
 
-       while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)
+       while ((!node || rb_is_black(node)) && node != root->rb_node)
        {
                if (parent->rb_left == node)
                {
                        other = parent->rb_right;
-                       if (other->rb_color == RB_RED)
+                       if (rb_is_red(other))
                        {
-                               other->rb_color = RB_BLACK;
-                               parent->rb_color = RB_RED;
+                               rb_set_black(other);
+                               rb_set_red(parent);
                                __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))
+                       if ((!other->rb_left || rb_is_black(other->rb_left)) &&
+                           (!other->rb_right || rb_is_black(other->rb_right)))
                        {
-                               other->rb_color = RB_RED;
+                               rb_set_red(other);
                                node = parent;
-                               parent = node->rb_parent;
+                               parent = rb_parent(node);
                        }
                        else
                        {
-                               if (!other->rb_right ||
-                                   other->rb_right->rb_color == RB_BLACK)
+                               if (!other->rb_right || rb_is_black(other->rb_right))
                                {
-                                       register struct rb_node *o_left;
-                                       if ((o_left = other->rb_left))
-                                               o_left->rb_color = RB_BLACK;
-                                       other->rb_color = RB_RED;
+                                       rb_set_black(other->rb_left);
+                                       rb_set_red(other);
                                        __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_set_color(other, rb_color(parent));
+                               rb_set_black(parent);
+                               rb_set_black(other->rb_right);
                                __rb_rotate_left(parent, root);
                                node = root->rb_node;
                                break;
@@ -179,38 +179,32 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
                else
                {
                        other = parent->rb_left;
-                       if (other->rb_color == RB_RED)
+                       if (rb_is_red(other))
                        {
-                               other->rb_color = RB_BLACK;
-                               parent->rb_color = RB_RED;
+                               rb_set_black(other);
+                               rb_set_red(parent);
                                __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))
+                       if ((!other->rb_left || rb_is_black(other->rb_left)) &&
+                           (!other->rb_right || rb_is_black(other->rb_right)))
                        {
-                               other->rb_color = RB_RED;
+                               rb_set_red(other);
                                node = parent;
-                               parent = node->rb_parent;
+                               parent = rb_parent(node);
                        }
                        else
                        {
-                               if (!other->rb_left ||
-                                   other->rb_left->rb_color == RB_BLACK)
+                               if (!other->rb_left || rb_is_black(other->rb_left))
                                {
-                                       register struct rb_node *o_right;
-                                       if ((o_right = other->rb_right))
-                                               o_right->rb_color = RB_BLACK;
-                                       other->rb_color = RB_RED;
+                                       rb_set_black(other->rb_right);
+                                       rb_set_red(other);
                                        __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_set_color(other, rb_color(parent));
+                               rb_set_black(parent);
+                               rb_set_black(other->rb_left);
                                __rb_rotate_right(parent, root);
                                node = root->rb_node;
                                break;
@@ -218,7 +212,7 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
                }
        }
        if (node)
-               node->rb_color = RB_BLACK;
+               rb_set_black(node);
 }
 
 void rb_erase(struct rb_node *node, struct rb_root *root)
@@ -237,49 +231,42 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
                node = node->rb_right;
                while ((left = node->rb_left) != NULL)
                        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;
+               if (rb_parent(old)) {
+                       if (rb_parent(old)->rb_left == old)
+                               rb_parent(old)->rb_left = node;
                        else
-                               parent->rb_right = child;
-               }
-               else
-                       root->rb_node = child;
+                               rb_parent(old)->rb_right = node;
+               } else
+                       root->rb_node = node;
 
-               if (node->rb_parent == old)
+               child = node->rb_right;
+               parent = rb_parent(node);
+               color = rb_color(node);
+
+               if (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;
+               } else {
+                       if (child)
+                               rb_set_parent(child, parent);
+                       parent->rb_left = child;
 
-               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;
+                       node->rb_right = old->rb_right;
+                       rb_set_parent(old->rb_right, node);
+               }
+
+               node->rb_parent_color = old->rb_parent_color;
+               node->rb_left = old->rb_left;
+               rb_set_parent(old->rb_left, 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;
+       parent = rb_parent(node);
+       color = rb_color(node);
 
        if (child)
-               child->rb_parent = parent;
+               rb_set_parent(child, parent);
        if (parent)
        {
                if (parent->rb_left == node)
@@ -296,10 +283,78 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
 }
 EXPORT_SYMBOL(rb_erase);
 
+static void rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
+{
+       struct rb_node *parent;
+
+up:
+       func(node, data);
+       parent = rb_parent(node);
+       if (!parent)
+               return;
+
+       if (node == parent->rb_left && parent->rb_right)
+               func(parent->rb_right, data);
+       else if (parent->rb_left)
+               func(parent->rb_left, data);
+
+       node = parent;
+       goto up;
+}
+
+/*
+ * after inserting @node into the tree, update the tree to account for
+ * both the new entry and any damage done by rebalance
+ */
+void rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
+{
+       if (node->rb_left)
+               node = node->rb_left;
+       else if (node->rb_right)
+               node = node->rb_right;
+
+       rb_augment_path(node, func, data);
+}
+
+/*
+ * before removing the node, find the deepest node on the rebalance path
+ * that will still be there after @node gets removed
+ */
+struct rb_node *rb_augment_erase_begin(struct rb_node *node)
+{
+       struct rb_node *deepest;
+
+       if (!node->rb_right && !node->rb_left)
+               deepest = rb_parent(node);
+       else if (!node->rb_right)
+               deepest = node->rb_left;
+       else if (!node->rb_left)
+               deepest = node->rb_right;
+       else {
+               deepest = rb_next(node);
+               if (deepest->rb_right)
+                       deepest = deepest->rb_right;
+               else if (rb_parent(deepest) != node)
+                       deepest = rb_parent(deepest);
+       }
+
+       return deepest;
+}
+
+/*
+ * after removal, update the tree to account for the removed entry
+ * and any rebalance damage.
+ */
+void rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
+{
+       if (node)
+               rb_augment_path(node, func, data);
+}
+
 /*
  * This function returns the first node (in sort order) of the tree.
  */
-struct rb_node *rb_first(struct rb_root *root)
+struct rb_node *rb_first(const struct rb_root *root)
 {
        struct rb_node  *n;
 
@@ -312,7 +367,7 @@ struct rb_node *rb_first(struct rb_root *root)
 }
 EXPORT_SYMBOL(rb_first);
 
-struct rb_node *rb_last(struct rb_root *root)
+struct rb_node *rb_last(const struct rb_root *root)
 {
        struct rb_node  *n;
 
@@ -325,15 +380,20 @@ struct rb_node *rb_last(struct rb_root *root)
 }
 EXPORT_SYMBOL(rb_last);
 
-struct rb_node *rb_next(struct rb_node *node)
+struct rb_node *rb_next(const struct rb_node *node)
 {
+       struct rb_node *parent;
+
+       if (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 node;
+               return (struct rb_node *)node;
        }
 
        /* No right-hand children.  Everything down and left is
@@ -342,37 +402,42 @@ struct rb_node *rb_next(struct rb_node *node)
           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 (node->rb_parent && node == node->rb_parent->rb_right)
-               node = node->rb_parent;
+       while ((parent = rb_parent(node)) && node == parent->rb_right)
+               node = parent;
 
-       return node->rb_parent;
+       return parent;
 }
 EXPORT_SYMBOL(rb_next);
 
-struct rb_node *rb_prev(struct rb_node *node)
+struct rb_node *rb_prev(const struct rb_node *node)
 {
+       struct rb_node *parent;
+
+       if (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 node;
+               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 (node->rb_parent && node == node->rb_parent->rb_left)
-               node = node->rb_parent;
+       while ((parent = rb_parent(node)) && node == parent->rb_left)
+               node = parent;
 
-       return node->rb_parent;
+       return parent;
 }
 EXPORT_SYMBOL(rb_prev);
 
 void rb_replace_node(struct rb_node *victim, struct rb_node *new,
                     struct rb_root *root)
 {
-       struct rb_node *parent = victim->rb_parent;
+       struct rb_node *parent = rb_parent(victim);
 
        /* Set the surrounding nodes to point to the replacement */
        if (parent) {
@@ -384,9 +449,9 @@ void rb_replace_node(struct rb_node *victim, struct rb_node *new,
                root->rb_node = new;
        }
        if (victim->rb_left)
-               victim->rb_left->rb_parent = new;
+               rb_set_parent(victim->rb_left, new);
        if (victim->rb_right)
-               victim->rb_right->rb_parent = new;
+               rb_set_parent(victim->rb_right, new);
 
        /* Copy the pointers/colour from the victim to the replacement */
        *new = *victim;