static void
recolor(rbtree_t *tree,
rbtree_node_t *parent,
rbtree_node_t *node)
{
rbtree_node_t *sibling;
while(is_black(node) && node != tree->root)
{
int left = (node == parent->child[LEFT]);
sibling = parent->child[left];
if(is_red(sibling))
{
set_black(sibling);
set_red(parent);
rbtree_rotate(tree, parent, left);
sibling = parent->child[left];
}
if(is_black(sibling->child[LEFT]) && is_black(sibling->child[RIGHT]))
{
set_red(sibling);
node = parent;
parent = get_parent(node);
}
else
{
if(is_black(sibling->child[left]))
{
set_black(sibling->child[!left]);
set_red(sibling);
rbtree_rotate(tree, sibling, !left);
sibling = parent->child[left];
}
if(is_black(parent))
set_black(sibling);
else
set_red(sibling);
set_black(parent);
set_black(sibling->child[left]);
rbtree_rotate(tree, parent, left);
node = tree->root;
}
}
if(node != NULL)
set_black(node);
}
/**
* Rebalance the rbtree, so that no more than two RBTREE_COLOR_RED
* nodes appear in a row.
*/
static void
c_rbtree_rebalance(struct c_rbtree_entry *node)
{
struct c_rbtree_entry *parent, *grandfather, *uncle;
while (node)
{
parent = node->rb_parent;
grandfather = (parent ? parent->rb_parent : NULL);
if (grandfather && parent == grandfather->rb_left)
uncle = grandfather->rb_right;
else if (grandfather && parent == grandfather->rb_right)
uncle = grandfather->rb_left;
/* If parent is black and we are red, we're fine. */
if (parent->rb_color == RBTREE_COLOR_BLACK)
return;
if (uncle && uncle->rb_color == RBTREE_COLOR_RED)
{
parent->rb_color = RBTREE_COLOR_BLACK;
uncle->rb_color = RBTREE_COLOR_BLACK;
grandfather->rb_color = RBTREE_COLOR_RED;
node = grandfather;
}
else
{
if (node == parent->rb_right &&
parent == grandfather->rb_left)
{
rbtree_rotate(parent);
node = node->rb_left;
parent = node ? node->rb_parent : NULL;
grandfather = parent ? parent->rb_parent : NULL;
}
else if (node == parent->rb_left &&
parent == grandfather->rb_right)
{
rbtree_rotate(parent);
node = node->rb_right;
parent = node ? node->rb_parent : NULL;
grandfather = parent ? parent->rb_parent : NULL;
}
node->rb_parent->rb_color = RBTREE_COLOR_BLACK;
grandfather->rb_color = RBTREE_COLOR_RED;
if (node == parent->rb_left &&
parent == grandfather->rb_left)
rbtree_rotate(grandfather);
else if (node == parent->rb_right &&
parent == grandfather->rb_right)
rbtree_rotate(grandfather);
return;
}
}
return;
}
