[RBTREE] Merge colour and parent fields of struct rb_node.
We only used a single bit for colour information, so having a whole machine word of space allocated for it was a bit wasteful. Instead, store it in the lowest bit of the 'parent' pointer, since that was always going to be aligned anyway. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
parent
1975e59375
commit
55a981027f
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@ -99,28 +99,35 @@ static inline struct page * rb_insert_page_cache(struct inode * inode,
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struct rb_node
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{
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struct rb_node *rb_parent;
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int rb_color;
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unsigned long rb_parent_colour;
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#define RB_RED 0
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#define RB_BLACK 1
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struct rb_node *rb_right;
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struct rb_node *rb_left;
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};
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#define rb_parent(r) ((r)->rb_parent)
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#define rb_set_parent(r,p) do { (r)->rb_parent = p; } while (0)
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#define rb_colour(r) ((r)->rb_colour)
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#define rb_is_red(r) ((r)->colour == RB_RED)
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#define rb_is_black(r) ((r)->colour == RB_BLACK)
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#define rb_set_red(r) do { (r)->colour = RB_RED; } while (0)
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#define rb_set_black(r) do { (r)->colour = RB_BLACK; } while (0)
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#define rb_set_colour(r,c) do { (r)->colour = (c); } while (0)
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struct rb_root
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{
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struct rb_node *rb_node;
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};
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#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_colour & ~3))
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#define rb_colour(r) ((r)->rb_parent_colour & 1)
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#define rb_is_red(r) (!rb_colour(r))
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#define rb_is_black(r) rb_colour(r)
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#define rb_set_red(r) do { (r)->rb_parent_colour &= ~1; } while (0)
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#define rb_set_black(r) do { (r)->rb_parent_colour |= 1; } while (0)
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static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
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{
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rb->rb_parent_colour = (rb->rb_parent_colour & 3) | (unsigned long)p;
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}
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static inline void rb_set_colour(struct rb_node *rb, int colour)
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{
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rb->rb_parent_colour = (rb->rb_parent_colour & ~1) | colour;
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}
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#define RB_ROOT (struct rb_root) { NULL, }
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#define rb_entry(ptr, type, member) container_of(ptr, type, member)
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@ -140,8 +147,7 @@ extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
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struct rb_node ** rb_link)
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{
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node->rb_parent = parent;
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node->rb_color = RB_RED;
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node->rb_parent_colour = (unsigned long )parent;
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node->rb_left = node->rb_right = NULL;
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*rb_link = node;
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176
lib/rbtree.c
176
lib/rbtree.c
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@ -26,60 +26,66 @@
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static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
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{
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struct rb_node *right = node->rb_right;
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struct rb_node *parent = rb_parent(node);
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if ((node->rb_right = right->rb_left))
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right->rb_left->rb_parent = node;
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rb_set_parent(right->rb_left, node);
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right->rb_left = node;
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if ((right->rb_parent = node->rb_parent))
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rb_set_parent(right, parent);
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if (parent)
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{
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if (node == node->rb_parent->rb_left)
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node->rb_parent->rb_left = right;
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if (node == parent->rb_left)
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parent->rb_left = right;
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else
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node->rb_parent->rb_right = right;
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parent->rb_right = right;
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}
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else
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root->rb_node = right;
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node->rb_parent = right;
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rb_set_parent(node, right);
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}
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static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
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{
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struct rb_node *left = node->rb_left;
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struct rb_node *parent = rb_parent(node);
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if ((node->rb_left = left->rb_right))
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left->rb_right->rb_parent = node;
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rb_set_parent(left->rb_right, node);
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left->rb_right = node;
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if ((left->rb_parent = node->rb_parent))
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rb_set_parent(left, parent);
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if (parent)
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{
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if (node == node->rb_parent->rb_right)
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node->rb_parent->rb_right = left;
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if (node == parent->rb_right)
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parent->rb_right = left;
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else
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node->rb_parent->rb_left = left;
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parent->rb_left = left;
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}
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else
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root->rb_node = left;
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node->rb_parent = left;
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rb_set_parent(node, left);
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}
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void rb_insert_color(struct rb_node *node, struct rb_root *root)
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{
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struct rb_node *parent, *gparent;
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while ((parent = node->rb_parent) && parent->rb_color == RB_RED)
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while ((parent = rb_parent(node)) && rb_is_red(parent))
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{
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gparent = parent->rb_parent;
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gparent = rb_parent(parent);
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if (parent == gparent->rb_left)
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{
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{
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register struct rb_node *uncle = gparent->rb_right;
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if (uncle && uncle->rb_color == RB_RED)
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if (uncle && rb_is_red(uncle))
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{
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uncle->rb_color = RB_BLACK;
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parent->rb_color = RB_BLACK;
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gparent->rb_color = RB_RED;
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rb_set_black(uncle);
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rb_set_black(parent);
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rb_set_red(gparent);
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node = gparent;
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continue;
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}
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@ -94,17 +100,17 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
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node = tmp;
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}
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parent->rb_color = RB_BLACK;
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gparent->rb_color = RB_RED;
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rb_set_black(parent);
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rb_set_red(gparent);
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__rb_rotate_right(gparent, root);
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} else {
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{
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register struct rb_node *uncle = gparent->rb_left;
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if (uncle && uncle->rb_color == RB_RED)
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if (uncle && rb_is_red(uncle))
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{
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uncle->rb_color = RB_BLACK;
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parent->rb_color = RB_BLACK;
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gparent->rb_color = RB_RED;
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rb_set_black(uncle);
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rb_set_black(parent);
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rb_set_red(gparent);
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node = gparent;
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continue;
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}
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@ -119,13 +125,13 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
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node = tmp;
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}
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parent->rb_color = RB_BLACK;
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gparent->rb_color = RB_RED;
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rb_set_black(parent);
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rb_set_red(gparent);
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__rb_rotate_left(gparent, root);
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}
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}
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root->rb_node->rb_color = RB_BLACK;
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rb_set_black(root->rb_node);
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}
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EXPORT_SYMBOL(rb_insert_color);
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@ -134,43 +140,40 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
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{
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struct rb_node *other;
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while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)
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while ((!node || rb_is_black(node)) && node != root->rb_node)
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{
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if (parent->rb_left == node)
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{
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other = parent->rb_right;
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if (other->rb_color == RB_RED)
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if (rb_is_red(other))
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{
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other->rb_color = RB_BLACK;
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parent->rb_color = RB_RED;
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rb_set_black(other);
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rb_set_red(parent);
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__rb_rotate_left(parent, root);
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other = parent->rb_right;
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}
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if ((!other->rb_left ||
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other->rb_left->rb_color == RB_BLACK)
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&& (!other->rb_right ||
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other->rb_right->rb_color == RB_BLACK))
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if ((!other->rb_left || rb_is_black(other->rb_left)) &&
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(!other->rb_right || rb_is_black(other->rb_right)))
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{
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other->rb_color = RB_RED;
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rb_set_red(other);
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node = parent;
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parent = node->rb_parent;
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parent = rb_parent(node);
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}
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else
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{
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if (!other->rb_right ||
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other->rb_right->rb_color == RB_BLACK)
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if (!other->rb_right || rb_is_black(other->rb_right))
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{
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register struct rb_node *o_left;
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struct rb_node *o_left;
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if ((o_left = other->rb_left))
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o_left->rb_color = RB_BLACK;
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other->rb_color = RB_RED;
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rb_set_black(o_left);
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rb_set_red(other);
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__rb_rotate_right(other, root);
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other = parent->rb_right;
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}
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other->rb_color = parent->rb_color;
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parent->rb_color = RB_BLACK;
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rb_set_colour(other, rb_colour(parent));
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rb_set_black(parent);
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if (other->rb_right)
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other->rb_right->rb_color = RB_BLACK;
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rb_set_black(other->rb_right);
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__rb_rotate_left(parent, root);
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node = root->rb_node;
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break;
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@ -179,38 +182,35 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
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else
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{
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other = parent->rb_left;
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if (other->rb_color == RB_RED)
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if (rb_is_red(other))
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{
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other->rb_color = RB_BLACK;
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parent->rb_color = RB_RED;
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rb_set_black(other);
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rb_set_red(parent);
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__rb_rotate_right(parent, root);
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other = parent->rb_left;
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}
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if ((!other->rb_left ||
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other->rb_left->rb_color == RB_BLACK)
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&& (!other->rb_right ||
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other->rb_right->rb_color == RB_BLACK))
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if ((!other->rb_left || rb_is_black(other->rb_left)) &&
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(!other->rb_right || rb_is_black(other->rb_right)))
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{
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other->rb_color = RB_RED;
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rb_set_red(other);
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node = parent;
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parent = node->rb_parent;
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parent = rb_parent(node);
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}
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else
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{
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if (!other->rb_left ||
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other->rb_left->rb_color == RB_BLACK)
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if (!other->rb_left || rb_is_black(other->rb_left))
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{
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register struct rb_node *o_right;
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if ((o_right = other->rb_right))
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o_right->rb_color = RB_BLACK;
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other->rb_color = RB_RED;
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rb_set_black(o_right);
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rb_set_red(other);
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__rb_rotate_left(other, root);
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other = parent->rb_left;
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}
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other->rb_color = parent->rb_color;
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parent->rb_color = RB_BLACK;
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rb_set_colour(other, rb_colour(parent));
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rb_set_black(parent);
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if (other->rb_left)
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other->rb_left->rb_color = RB_BLACK;
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rb_set_black(other->rb_left);
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__rb_rotate_right(parent, root);
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node = root->rb_node;
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break;
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@ -218,7 +218,7 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
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}
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}
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if (node)
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node->rb_color = RB_BLACK;
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rb_set_black(node);
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}
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void rb_erase(struct rb_node *node, struct rb_root *root)
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@ -238,43 +238,41 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
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while ((left = node->rb_left) != NULL)
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node = left;
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child = node->rb_right;
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parent = node->rb_parent;
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color = node->rb_color;
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parent = rb_parent(node);
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color = rb_colour(node);
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if (child)
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child->rb_parent = parent;
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if (node->rb_parent == old) {
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rb_set_parent(child, parent);
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if (parent == old) {
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parent->rb_right = child;
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parent = node;
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} else
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parent->rb_left = child;
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node->rb_parent = old->rb_parent;
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node->rb_color = old->rb_color;
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node->rb_parent_colour = old->rb_parent_colour;
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node->rb_right = old->rb_right;
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node->rb_left = old->rb_left;
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if (old->rb_parent)
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if (rb_parent(old))
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{
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if (old->rb_parent->rb_left == old)
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old->rb_parent->rb_left = node;
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if (rb_parent(old)->rb_left == old)
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rb_parent(old)->rb_left = node;
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else
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old->rb_parent->rb_right = node;
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rb_parent(old)->rb_right = node;
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} else
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root->rb_node = node;
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old->rb_left->rb_parent = node;
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rb_set_parent(old->rb_left, node);
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if (old->rb_right)
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old->rb_right->rb_parent = node;
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rb_set_parent(old->rb_right, node);
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goto color;
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}
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parent = node->rb_parent;
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color = node->rb_color;
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parent = rb_parent(node);
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color = rb_colour(node);
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if (child)
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child->rb_parent = parent;
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rb_set_parent(child, parent);
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if (parent)
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{
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if (parent->rb_left == node)
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@ -322,6 +320,8 @@ EXPORT_SYMBOL(rb_last);
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struct rb_node *rb_next(struct rb_node *node)
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{
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struct rb_node *parent;
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/* If we have a right-hand child, go down and then left as far
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as we can. */
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if (node->rb_right) {
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@ -337,15 +337,17 @@ struct rb_node *rb_next(struct rb_node *node)
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ancestor is a right-hand child of its parent, keep going
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up. First time it's a left-hand child of its parent, said
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parent is our 'next' node. */
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while (node->rb_parent && node == node->rb_parent->rb_right)
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node = node->rb_parent;
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while ((parent = rb_parent(node)) && node == parent->rb_right)
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node = parent;
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return node->rb_parent;
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return parent;
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}
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EXPORT_SYMBOL(rb_next);
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struct rb_node *rb_prev(struct rb_node *node)
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{
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struct rb_node *parent;
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/* If we have a left-hand child, go down and then right as far
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as we can. */
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if (node->rb_left) {
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@ -357,17 +359,17 @@ struct rb_node *rb_prev(struct rb_node *node)
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/* No left-hand children. Go up till we find an ancestor which
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is a right-hand child of its parent */
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while (node->rb_parent && node == node->rb_parent->rb_left)
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node = node->rb_parent;
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while ((parent = rb_parent(node)) && node == parent->rb_left)
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node = parent;
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return node->rb_parent;
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return parent;
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}
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EXPORT_SYMBOL(rb_prev);
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void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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struct rb_root *root)
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{
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struct rb_node *parent = victim->rb_parent;
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struct rb_node *parent = rb_parent(victim);
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/* Set the surrounding nodes to point to the replacement */
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if (parent) {
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@ -379,9 +381,9 @@ void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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root->rb_node = new;
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}
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if (victim->rb_left)
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victim->rb_left->rb_parent = new;
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rb_set_parent(victim->rb_left, new);
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if (victim->rb_right)
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victim->rb_right->rb_parent = new;
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rb_set_parent(victim->rb_right, new);
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/* Copy the pointers/colour from the victim to the replacement */
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*new = *victim;
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