- Use the newly introduced rb_set_parent_color() function to flip the color
of nodes whose parent is already known.
- Optimize rb_parent() when the node is known to be red - there is no need
to mask out the color in that case.
- Flipping gparent's color to red requires us to fetch its rb_parent_color
field, so we can reuse it as the parent value for the next loop iteration.
Signed-off-by: Michel Lespinasse <wal...@google.com>
---
lib/rbtree.c | 26 ++++++++++++++++----------
1 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/lib/rbtree.c b/lib/rbtree.c
index f668886..56369d8 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -47,6 +47,11 @@ static inline void rb_set_parent_color(struct rb_node *rb,
rb->rb_parent_color = (unsigned long)p | color;
}
+static inline struct rb_node *rb_red_parent(struct rb_node *red)
+{
+ return (struct rb_node *)red->rb_parent_color;
+}
+
static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
{
struct rb_node *right = node->rb_right;
@@ -116,7 +121,7 @@ __rb_rotate_set_parents(struct rb_node *old, struct rb_node
*new,
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
- struct rb_node *parent, *gparent, *tmp;
+ struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
while (true) {
/*
@@ -126,23 +131,23 @@ void rb_insert_color(struct rb_node *node, struct rb_root
*root)
* Otherwise, take some corrective action as we don't
* want a red root or two consecutive red nodes.
*/
- parent = rb_parent(node);
if (!parent) {
- rb_set_black(node);
+ rb_set_parent_color(node, NULL, RB_BLACK);
break;
} else if (rb_is_black(parent))
break;
- gparent = rb_parent(parent);
+ gparent = rb_red_parent(parent);
if (parent == gparent->rb_left) {
tmp = gparent->rb_right;
if (tmp && rb_is_red(tmp)) {
/* Case 1 - color flips */
- rb_set_black(tmp);
- rb_set_black(parent);
- rb_set_red(gparent);
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ rb_set_parent_color(parent, gparent, RB_BLACK);
node = gparent;
+ parent = rb_parent(node);
+ rb_set_parent_color(node, parent, RB_RED);
continue;
}
@@ -168,10 +173,11 @@ void rb_insert_color(struct rb_node *node, struct rb_root
*root)
tmp = gparent->rb_left;
if (tmp && rb_is_red(tmp)) {
/* Case 1 - color flips */
- rb_set_black(tmp);
- rb_set_black(parent);
- rb_set_red(gparent);
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ rb_set_parent_color(parent, gparent, RB_BLACK);
node = gparent;
+ parent = rb_parent(node);
+ rb_set_parent_color(node, parent, RB_RED);
continue;
}
--
1.7.7.3
--
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