rbtree(3) BSD Library Functions Manual rbtree(3)
NAME
rbtree -- red-black tree
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/rbtree.h>
void
rb_tree_init(rb_tree_t *rbt, const rb_tree_ops_t *ops);
void *
rb_tree_insert_node(rb_tree_t *rbt, void *rb);
void
rb_tree_remove_node(rb_tree_t *rbt, void *rb);
void *
rb_tree_find_node(rb_tree_t *rbt, const void *key);
void *
rb_tree_find_node_geq(rb_tree_t *rbt, const void *key);
void *
rb_tree_find_node_leq(rb_tree_t *rbt, const void *key);
void *
rb_tree_iterate(rb_tree_t *rbt, void *rb, const unsigned int direction);
size_t
rb_tree_count(rb_tree_t *rbt);
DESCRIPTION
rbtree provides red-black trees. A red-black tree is a binary search
tree with the node color as an extra attribute. It fulfills a set of
conditions:
1. Every search path from the root to a leaf consists of the same
number of black nodes.
2. Each red node (except for the root) has a black parent.
3. Each leaf node is black.
Every operation on a red-black tree is bounded as O(lg n). The maximum
height of a red-black tree is 2lg (n+1).
TYPES
rb_tree_t
A red-black tree.
typedef signed int (* rbto_compare_nodes_fn)(void *context, const void
*node1, const void *node2);
The node-comparison operator. Defines an ordering on nodes.
Returns a negative value if the first node node1 precedes the
second node node2. Returns a positive value if the first node
node1 follows the second node node2. Returns 0 if the first
node node1 and the second node node2 are identical according to
the ordering.
typedef signed int (* rbto_compare_key_fn)(void *context, const void
*node, const void *key);
The node-key comparison operator. Defines the order of nodes
and keys. Returns a negative value if the node node precedes
the key key. Returns a positive value if the node node follows
the key key. Returns 0 if the node node is identical to the key
key according to the ordering.
rb_tree_ops_t
Defines the operator for comparing two nodes in the same tree,
the operator for comparing a node in the tree with a key, the
offset of member rb_node_t within a node, and the opaque context
passed to the operators. Members of rb_tree_ops_t are
rbto_compare_nodes_fn rbto_compare_nodes;
rbto_compare_key_fn rbto_compare_key;
size_t rbto_node_offset;
void *rbto_context;
rb_node_t
A node in a red-black tree has this structure as a member.
FUNCTIONS
rb_tree_init(rbt, ops)
Initialize the red-black tree rbt. Let the comparison operators
given by ops define the order of nodes in the tree for the pur-
poses of insertion, search, and iteration. rb_tree_init()
always succeeds.
rb_tree_insert_node(rbt, rb)
Insert the node rb into the tree rbt. Return inserted node on
success, already existing node on failure.
rb_tree_remove_node(rbt, rb)
Remove the node rb from the tree rbt.
rb_tree_find_node(rbt, key)
Search the tree rbt for a node exactly matching key. If no such
node is in the tree, return NULL. Otherwise, return the match-
ing node.
rb_tree_find_node_geq(rbt, key)
Search the tree rbt for a node that exactly matches key and
return it. If no such node is present, return the first node
following key or, if no such node is in the tree, return NULL.
rb_tree_find_node_leq(rbt, key)
Search the tree rbt for a node that exactly matches key and
return it. If no such node is present, return the first node
preceding key or, if no such node is in the tree, return NULL.
rb_tree_iterate(rbt, rb, direction)
If direction is RB_DIR_LEFT, return the node in the tree rbt
immediately preceding the node rb or, if rb is NULL, return the
last node in rbt or, if the tree is empty, return NULL.
If direction is RB_DIR_RIGHT, return the node in the tree rbt
immediately following the node rb or, if rb is NULL, return the
first node in rbt or, if the tree is empty, return NULL.
rb_tree_count(rbt)
Return the number of nodes in the tree rbt. If rbt is NULL, 0
is returned.
IMPLEMENTATION DETAILS
NetBSD 6.0 included a version of this API that returned the wrong result
when using rb_tree_iterate() to find the first or last node. This imple-
mentation does not have this bug. If you wish to maintain portability
with NetBSD 6.0, it is recomended that you use the RB_TREE_MIN() and
RB_TREE_MAX() macros rather than using rb_tree_iterate() directly.
SEE ALSO
queue(3)
HISTORY
The rbtree interface first appeared in NetBSD 6.0.
AUTHORS
Matt Thomas <matt@NetBSD.org> wrote rbtree.
Niels Provos <provos@citi.umich.edu> wrote the tree(3) manual page. Por-
tions of this page derive from that page.
BSD August 19, 2012 BSD
Mac OS X 10.9.1 - Generated Fri Jan 10 16:49:53 CST 2014