mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-29 15:14:18 +08:00
rbtree.txt: standardize document format
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - Mark document title; - Use :Author: for authorship; - mark a sub-section title as such; - mark literal blocks; - adjust identation where needed. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mauro Carvalho Chehab
Jonathan Corbet
parent
3b033380cb
commit
ce0f95a501
@ -1,7 +1,10 @@
|
||||
=================================
|
||||
Red-black Trees (rbtree) in Linux
|
||||
January 18, 2007
|
||||
Rob Landley <rob@landley.net>
|
||||
=============================
|
||||
=================================
|
||||
|
||||
|
||||
:Date: January 18, 2007
|
||||
:Author: Rob Landley <rob@landley.net>
|
||||
|
||||
What are red-black trees, and what are they for?
|
||||
------------------------------------------------
|
||||
@ -56,7 +59,7 @@ user of the rbtree code.
|
||||
Creating a new rbtree
|
||||
---------------------
|
||||
|
||||
Data nodes in an rbtree tree are structures containing a struct rb_node member:
|
||||
Data nodes in an rbtree tree are structures containing a struct rb_node member::
|
||||
|
||||
struct mytype {
|
||||
struct rb_node node;
|
||||
@ -78,7 +81,7 @@ Searching for a value in an rbtree
|
||||
Writing a search function for your tree is fairly straightforward: start at the
|
||||
root, compare each value, and follow the left or right branch as necessary.
|
||||
|
||||
Example:
|
||||
Example::
|
||||
|
||||
struct mytype *my_search(struct rb_root *root, char *string)
|
||||
{
|
||||
@ -110,7 +113,7 @@ The search for insertion differs from the previous search by finding the
|
||||
location of the pointer on which to graft the new node. The new node also
|
||||
needs a link to its parent node for rebalancing purposes.
|
||||
|
||||
Example:
|
||||
Example::
|
||||
|
||||
int my_insert(struct rb_root *root, struct mytype *data)
|
||||
{
|
||||
@ -140,11 +143,11 @@ Example:
|
||||
Removing or replacing existing data in an rbtree
|
||||
------------------------------------------------
|
||||
|
||||
To remove an existing node from a tree, call:
|
||||
To remove an existing node from a tree, call::
|
||||
|
||||
void rb_erase(struct rb_node *victim, struct rb_root *tree);
|
||||
|
||||
Example:
|
||||
Example::
|
||||
|
||||
struct mytype *data = mysearch(&mytree, "walrus");
|
||||
|
||||
@ -153,7 +156,7 @@ Example:
|
||||
myfree(data);
|
||||
}
|
||||
|
||||
To replace an existing node in a tree with a new one with the same key, call:
|
||||
To replace an existing node in a tree with a new one with the same key, call::
|
||||
|
||||
void rb_replace_node(struct rb_node *old, struct rb_node *new,
|
||||
struct rb_root *tree);
|
||||
@ -166,7 +169,7 @@ Iterating through the elements stored in an rbtree (in sort order)
|
||||
|
||||
Four functions are provided for iterating through an rbtree's contents in
|
||||
sorted order. These work on arbitrary trees, and should not need to be
|
||||
modified or wrapped (except for locking purposes):
|
||||
modified or wrapped (except for locking purposes)::
|
||||
|
||||
struct rb_node *rb_first(struct rb_root *tree);
|
||||
struct rb_node *rb_last(struct rb_root *tree);
|
||||
@ -184,7 +187,7 @@ which the containing data structure may be accessed with the container_of()
|
||||
macro, and individual members may be accessed directly via
|
||||
rb_entry(node, type, member).
|
||||
|
||||
Example:
|
||||
Example::
|
||||
|
||||
struct rb_node *node;
|
||||
for (node = rb_first(&mytree); node; node = rb_next(node))
|
||||
@ -241,7 +244,8 @@ user should have a single rb_erase_augmented() call site in order to limit
|
||||
compiled code size.
|
||||
|
||||
|
||||
Sample usage:
|
||||
Sample usage
|
||||
^^^^^^^^^^^^
|
||||
|
||||
Interval tree is an example of augmented rb tree. Reference -
|
||||
"Introduction to Algorithms" by Cormen, Leiserson, Rivest and Stein.
|
||||
@ -259,12 +263,12 @@ This "extra information" stored in each node is the maximum hi
|
||||
information can be maintained at each node just be looking at the node
|
||||
and its immediate children. And this will be used in O(log n) lookup
|
||||
for lowest match (lowest start address among all possible matches)
|
||||
with something like:
|
||||
with something like::
|
||||
|
||||
struct interval_tree_node *
|
||||
interval_tree_first_match(struct rb_root *root,
|
||||
unsigned long start, unsigned long last)
|
||||
{
|
||||
struct interval_tree_node *
|
||||
interval_tree_first_match(struct rb_root *root,
|
||||
unsigned long start, unsigned long last)
|
||||
{
|
||||
struct interval_tree_node *node;
|
||||
|
||||
if (!root->rb_node)
|
||||
@ -301,13 +305,13 @@ interval_tree_first_match(struct rb_root *root,
|
||||
}
|
||||
return NULL; /* No match */
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Insertion/removal are defined using the following augmented callbacks:
|
||||
Insertion/removal are defined using the following augmented callbacks::
|
||||
|
||||
static inline unsigned long
|
||||
compute_subtree_last(struct interval_tree_node *node)
|
||||
{
|
||||
static inline unsigned long
|
||||
compute_subtree_last(struct interval_tree_node *node)
|
||||
{
|
||||
unsigned long max = node->last, subtree_last;
|
||||
if (node->rb.rb_left) {
|
||||
subtree_last = rb_entry(node->rb.rb_left,
|
||||
@ -322,10 +326,10 @@ compute_subtree_last(struct interval_tree_node *node)
|
||||
max = subtree_last;
|
||||
}
|
||||
return max;
|
||||
}
|
||||
}
|
||||
|
||||
static void augment_propagate(struct rb_node *rb, struct rb_node *stop)
|
||||
{
|
||||
static void augment_propagate(struct rb_node *rb, struct rb_node *stop)
|
||||
{
|
||||
while (rb != stop) {
|
||||
struct interval_tree_node *node =
|
||||
rb_entry(rb, struct interval_tree_node, rb);
|
||||
@ -335,20 +339,20 @@ static void augment_propagate(struct rb_node *rb, struct rb_node *stop)
|
||||
node->__subtree_last = subtree_last;
|
||||
rb = rb_parent(&node->rb);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static void augment_copy(struct rb_node *rb_old, struct rb_node *rb_new)
|
||||
{
|
||||
static void augment_copy(struct rb_node *rb_old, struct rb_node *rb_new)
|
||||
{
|
||||
struct interval_tree_node *old =
|
||||
rb_entry(rb_old, struct interval_tree_node, rb);
|
||||
struct interval_tree_node *new =
|
||||
rb_entry(rb_new, struct interval_tree_node, rb);
|
||||
|
||||
new->__subtree_last = old->__subtree_last;
|
||||
}
|
||||
}
|
||||
|
||||
static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new)
|
||||
{
|
||||
static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new)
|
||||
{
|
||||
struct interval_tree_node *old =
|
||||
rb_entry(rb_old, struct interval_tree_node, rb);
|
||||
struct interval_tree_node *new =
|
||||
@ -356,15 +360,15 @@ static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new)
|
||||
|
||||
new->__subtree_last = old->__subtree_last;
|
||||
old->__subtree_last = compute_subtree_last(old);
|
||||
}
|
||||
}
|
||||
|
||||
static const struct rb_augment_callbacks augment_callbacks = {
|
||||
static const struct rb_augment_callbacks augment_callbacks = {
|
||||
augment_propagate, augment_copy, augment_rotate
|
||||
};
|
||||
};
|
||||
|
||||
void interval_tree_insert(struct interval_tree_node *node,
|
||||
struct rb_root *root)
|
||||
{
|
||||
void interval_tree_insert(struct interval_tree_node *node,
|
||||
struct rb_root *root)
|
||||
{
|
||||
struct rb_node **link = &root->rb_node, *rb_parent = NULL;
|
||||
unsigned long start = node->start, last = node->last;
|
||||
struct interval_tree_node *parent;
|
||||
@ -383,10 +387,10 @@ void interval_tree_insert(struct interval_tree_node *node,
|
||||
node->__subtree_last = last;
|
||||
rb_link_node(&node->rb, rb_parent, link);
|
||||
rb_insert_augmented(&node->rb, root, &augment_callbacks);
|
||||
}
|
||||
}
|
||||
|
||||
void interval_tree_remove(struct interval_tree_node *node,
|
||||
struct rb_root *root)
|
||||
{
|
||||
void interval_tree_remove(struct interval_tree_node *node,
|
||||
struct rb_root *root)
|
||||
{
|
||||
rb_erase_augmented(&node->rb, root, &augment_callbacks);
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user