forked from Imagelibrary/rtems
93 lines
4.8 KiB
Perl
93 lines
4.8 KiB
Perl
@c
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@c Copyright 2014 Gedare Bloom.
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@c All rights reserved.
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@chapter Red-Black Trees
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@cindex rbtrees
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@section Introduction
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The Red-Black Tree API is an interface to the SuperCore (score) rbtree
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implementation. Within RTEMS, red-black trees are used when a binary search
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tree is needed, including dynamic priority thread queues and non-contiguous
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heap memory. The Red-Black Tree API provided by RTEMS is:
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@itemize @bullet
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@c build_id
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@item @code{@value{DIRPREFIX}rtems_rbtree_node} - Red-Black Tree node embedded in another struct
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@item @code{@value{DIRPREFIX}rtems_rbtree_control} - Red-Black Tree control node for an entire tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_initialize} - initialize the red-black tree with nodes
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@item @code{@value{DIRPREFIX}rtems_rbtree_initialize_empty} - initialize the red-black tree as empty
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@item @code{@value{DIRPREFIX}rtems_rbtree_set_off_tree} - Clear a node's links
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@item @code{@value{DIRPREFIX}rtems_rbtree_root} - Return the red-black tree's root node
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@item @code{@value{DIRPREFIX}rtems_rbtree_min} - Return the red-black tree's minimum node
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@item @code{@value{DIRPREFIX}rtems_rbtree_max} - Return the red-black tree's maximum node
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@item @code{@value{DIRPREFIX}rtems_rbtree_left} - Return a node's left child node
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@item @code{@value{DIRPREFIX}rtems_rbtree_right} - Return a node's right child node
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@item @code{@value{DIRPREFIX}rtems_rbtree_parent} - Return a node's parent node
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@item @code{@value{DIRPREFIX}rtems_rbtree_are_nodes_equal} - Are the node's equal ?
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@item @code{@value{DIRPREFIX}rtems_rbtree_is_empty} - Is the red-black tree empty ?
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@item @code{@value{DIRPREFIX}rtems_rbtree_is_min} - Is the Node the minimum in the red-black tree ?
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@item @code{@value{DIRPREFIX}rtems_rbtree_is_max} - Is the Node the maximum in the red-black tree ?
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@item @code{@value{DIRPREFIX}rtems_rbtree_is_root} - Is the Node the root of the red-black tree ?
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@item @code{@value{DIRPREFIX}rtems_rbtree_find} - Find the node with a matching key in the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_predecessor} - Return the in-order predecessor of a node.
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@item @code{@value{DIRPREFIX}rtems_rbtree_successor} - Return the in-order successor of a node.
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@item @code{@value{DIRPREFIX}rtems_rbtree_extract} - Remove the node from the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_get_min} - Remove the minimum node from the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_get_max} - Remove the maximum node from the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_peek_min} - Returns the minimum node from the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_peek_max} - Returns the maximum node from the red-black tree
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@item @code{@value{DIRPREFIX}rtems_rbtree_find_control} - Returns the control node of a red-black tree given a node in the tree.
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@item @code{@value{DIRPREFIX}rtems_rbtree_insert} - Add the node to the red-black tree
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@end itemize
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@section Background
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The Red-Black Trees API is a thin layer above the SuperCore Red-Black Trees
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implementation. A Red-Black Tree is defined by a control node with pointers to
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the root, minimum, and maximum nodes in the tree. Each node in the tree
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consists of a parent pointer, two children pointers, and a color attribute. A
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tree is parameterized as either unique, meaning identical keys are rejected, or
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not, in which case duplicate keys are allowed.
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Users must provide a comparison functor that gets passed to functions that need
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to compare nodes. In addition, no internal synchronization is offered within
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the red-black tree implementation, thus users must ensure at most one thread
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accesses a red-black tree instance at a time.
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@subsection Nodes
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A red-black tree is made up from nodes that orginate from a red-black tree control
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object. A node is of type @code{@value{DIRPREFIX}rtems_rbtree_node}. The node
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is designed to be part of a user data structure. To obtain the encapsulating
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structure users can use the @code{RTEMS_CONTAINER_OF} macro.
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The node can be placed anywhere within the user's structure and the macro will
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calculate the structure's address from the node's address.
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@subsection Controls
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A red-black tree is rooted with a control object. Red-Black Tree control
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provide the user with access to the nodes on the red-black tree. The
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implementation does not require special checks for manipulating the root of the
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red-black tree. To accomplish this the
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@code{@value{DIRPREFIX}rtems_rbtree_control} structure is treated as a
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@code{@value{DIRPREFIX}rtems_rbtree_node} structure with a @code{NULL} parent
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and left child pointing to the root.
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@section Operations
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Examples for using the red-black trees
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can be found in the testsuites/sptests/sprbtree01/init.c file.
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@section Directives
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@subsection Documentation for the Red-Black Tree Directives
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@cindex rbtree doc
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Source documentation for the Red-Black Tree API can be found in the
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generated Doxygen output for cpukit/sapi.
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