From 97e834c5040b85e133d8d922111a62b2b853a406 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 23 Mar 2012 15:02:15 -0700 Subject: prio_tree: introduce prio_set_parent() Introduce prio_set_parent() to abstract the operation which is used to attach the node to its parent. Signed-off-by: Xiao Guangrong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/prio_tree.c | 47 ++++++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 25 deletions(-) (limited to 'lib') diff --git a/lib/prio_tree.c b/lib/prio_tree.c index 928482bb838..8d443af03b4 100644 --- a/lib/prio_tree.c +++ b/lib/prio_tree.c @@ -85,6 +85,17 @@ static inline unsigned long prio_tree_maxindex(unsigned int bits) return index_bits_to_maxindex[bits - 1]; } +static void prio_set_parent(struct prio_tree_node *parent, + struct prio_tree_node *child, bool left) +{ + if (left) + parent->left = child; + else + parent->right = child; + + child->parent = parent; +} + /* * Extend a priority search tree so that it can store a node with heap_index * max_heap_index. In the worst case, this algorithm takes O((log n)^2). @@ -113,15 +124,12 @@ static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root, prio_tree_remove(root, root->prio_tree_node); INIT_PRIO_TREE_NODE(tmp); - prev->left = tmp; - tmp->parent = prev; + prio_set_parent(prev, tmp, true); prev = tmp; } - if (!prio_tree_empty(root)) { - prev->left = root->prio_tree_node; - prev->left->parent = prev; - } + if (!prio_tree_empty(root)) + prio_set_parent(prev, root->prio_tree_node, true); root->prio_tree_node = node; return node; @@ -142,23 +150,14 @@ struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root, * and does not help much to improve performance (IMO). */ root->prio_tree_node = node; - } else { - node->parent = old->parent; - if (old->parent->left == old) - old->parent->left = node; - else - old->parent->right = node; - } + } else + prio_set_parent(old->parent, node, old->parent->left == old); - if (!prio_tree_left_empty(old)) { - node->left = old->left; - old->left->parent = node; - } + if (!prio_tree_left_empty(old)) + prio_set_parent(node, old->left, true); - if (!prio_tree_right_empty(old)) { - node->right = old->right; - old->right->parent = node; - } + if (!prio_tree_right_empty(old)) + prio_set_parent(node, old->right, false); return old; } @@ -218,16 +217,14 @@ struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root, if (index & mask) { if (prio_tree_right_empty(cur)) { INIT_PRIO_TREE_NODE(node); - cur->right = node; - node->parent = cur; + prio_set_parent(cur, node, false); return res; } else cur = cur->right; } else { if (prio_tree_left_empty(cur)) { INIT_PRIO_TREE_NODE(node); - cur->left = node; - node->parent = cur; + prio_set_parent(cur, node, true); return res; } else cur = cur->left; -- cgit v1.2.3