mirror of
https://gitlab.freedesktop.org/libbsd/libbsd.git
synced 2025-01-08 11:02:24 +01:00
man: Update tree(3) man page from OpenBSD
This man page has a BSD-3-clause-author license instead of the old BSD-4-clause license.
This commit is contained in:
Guillem Jover
parent
48107fc8c4
commit
fafcc397ac
2
COPYING
2
COPYING
@ -8,7 +8,6 @@ License: BSD-3-clause
|
||||
|
||||
Files:
|
||||
man/arc4random.3bsd
|
||||
man/tree.3bsd
|
||||
Copyright:
|
||||
Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
|
||||
All rights reserved.
|
||||
@ -348,6 +347,7 @@ License: BSD-2-clause-verbatim
|
||||
Files:
|
||||
include/bsd/sys/tree.h
|
||||
man/fparseln.3bsd
|
||||
man/tree.3bsd
|
||||
src/fparseln.c
|
||||
Copyright:
|
||||
Copyright © 1997 Christos Zoulas.
|
||||
|
||||
391
man/tree.3bsd
391
man/tree.3bsd
@ -1,36 +1,29 @@
|
||||
.\" $OpenBSD: tree.3,v 1.7 2002/06/12 01:09:20 provos Exp $
|
||||
.\"
|
||||
.\" Copyright 2002 Niels Provos <provos@citi.umich.edu>
|
||||
.\" All rights reserved.
|
||||
.\"
|
||||
.\" Redistribution and use in source and binary forms, with or without
|
||||
.\" modification, are permitted provided that the following conditions
|
||||
.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice, this list of conditions and the following disclaimer.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice, this list of conditions and the following disclaimer in the
|
||||
.\" documentation and/or other materials provided with the distribution.
|
||||
.\" 3. All advertising materials mentioning features or use of this software
|
||||
.\" must display the following acknowledgement:
|
||||
.\" This product includes software developed by Niels Provos.
|
||||
.\" 4. The name of the author may not be used to endorse or promote products
|
||||
.\" derived from this software without specific prior written permission.
|
||||
.\"
|
||||
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
||||
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
||||
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
||||
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
||||
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
||||
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd December 27, 2007
|
||||
.\" $OpenBSD: tree.3,v 1.30 2019/05/10 13:13:14 florian Exp $
|
||||
.\"/*
|
||||
.\" * Copyright 2002 Niels Provos <provos@citi.umich.edu>
|
||||
.\" * All rights reserved.
|
||||
.\" *
|
||||
.\" * Redistribution and use in source and binary forms, with or without
|
||||
.\" * modification, are permitted provided that the following conditions
|
||||
.\" * are met:
|
||||
.\" * 1. Redistributions of source code must retain the above copyright
|
||||
.\" * notice, this list of conditions and the following disclaimer.
|
||||
.\" * 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" * notice, this list of conditions and the following disclaimer in the
|
||||
.\" * documentation and/or other materials provided with the distribution.
|
||||
.\" *
|
||||
.\" * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
||||
.\" * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
||||
.\" * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
||||
.\" * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
.\" * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
||||
.\" * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
.\" * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
.\" * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
.\" * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
||||
.\" * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
.\" */
|
||||
.Dd May 10 2019
|
||||
.Dt TREE 3bsd
|
||||
.Os
|
||||
.Sh NAME
|
||||
@ -70,7 +63,9 @@
|
||||
.Nm RB_RIGHT ,
|
||||
.Nm RB_PARENT ,
|
||||
.Nm RB_FOREACH ,
|
||||
.Nm RB_FOREACH_SAFE ,
|
||||
.Nm RB_FOREACH_REVERSE ,
|
||||
.Nm RB_FOREACH_REVERSE_SAFE ,
|
||||
.Nm RB_INIT ,
|
||||
.Nm RB_INSERT ,
|
||||
.Nm RB_REMOVE
|
||||
@ -84,88 +79,92 @@
|
||||
(See
|
||||
.Xr libbsd 7
|
||||
for include usage.)
|
||||
.Fn SPLAY_PROTOTYPE NAME TYPE FIELD CMP
|
||||
.Fn SPLAY_GENERATE NAME TYPE FIELD CMP
|
||||
.Fn SPLAY_ENTRY TYPE
|
||||
.Fn SPLAY_HEAD HEADNAME TYPE
|
||||
.Pp
|
||||
.Fn SPLAY_PROTOTYPE "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn SPLAY_GENERATE "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn SPLAY_ENTRY "TYPE"
|
||||
.Fn SPLAY_HEAD "HEADNAME" "TYPE"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_INITIALIZER "SPLAY_HEAD *head"
|
||||
.Fn SPLAY_ROOT "SPLAY_HEAD *head"
|
||||
.Ft bool
|
||||
.Ft "int"
|
||||
.Fn SPLAY_EMPTY "SPLAY_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_NEXT NAME "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Fn SPLAY_NEXT "NAME" "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_MIN NAME "SPLAY_HEAD *head"
|
||||
.Fn SPLAY_MIN "NAME" "SPLAY_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_MAX NAME "SPLAY_HEAD *head"
|
||||
.Fn SPLAY_MAX "NAME" "SPLAY_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_FIND NAME "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Fn SPLAY_FIND "NAME" "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_LEFT "struct TYPE *elm" "SPLAY_ENTRY NAME"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_RIGHT "struct TYPE *elm" "SPLAY_ENTRY NAME"
|
||||
.Fn SPLAY_FOREACH VARNAME NAME "SPLAY_HEAD *head"
|
||||
.Fn SPLAY_FOREACH "VARNAME" "NAME" "SPLAY_HEAD *head"
|
||||
.Ft void
|
||||
.Fn SPLAY_INIT "SPLAY_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_INSERT NAME "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Fn SPLAY_INSERT "NAME" "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn SPLAY_REMOVE NAME "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_PROTOTYPE NAME TYPE FIELD CMP
|
||||
.Fn RB_PROTOTYPE_STATIC NAME TYPE FIELD CMP
|
||||
.Fn RB_GENERATE NAME TYPE FIELD CMP
|
||||
.Fn RB_GENERATE_STATIC NAME TYPE FIELD CMP
|
||||
.Fn RB_ENTRY TYPE
|
||||
.Fn RB_HEAD HEADNAME TYPE
|
||||
.Fn SPLAY_REMOVE "NAME" "SPLAY_HEAD *head" "struct TYPE *elm"
|
||||
.Pp
|
||||
.Fn RB_PROTOTYPE "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn RB_PROTOTYPE_STATIC "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn RB_GENERATE "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn RB_GENERATE_STATIC "NAME" "TYPE" "FIELD" "CMP"
|
||||
.Fn RB_ENTRY "TYPE"
|
||||
.Fn RB_HEAD "HEADNAME" "TYPE"
|
||||
.Fn RB_INITIALIZER "RB_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_ROOT "RB_HEAD *head"
|
||||
.Ft "bool"
|
||||
.Ft "int"
|
||||
.Fn RB_EMPTY "RB_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_NEXT NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_NEXT "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_PREV NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_PREV "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_MIN NAME "RB_HEAD *head"
|
||||
.Fn RB_MIN "NAME" "RB_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_MAX NAME "RB_HEAD *head"
|
||||
.Fn RB_MAX "NAME" "RB_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_FIND NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_FIND "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_NFIND NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_NFIND "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_LEFT "struct TYPE *elm" "RB_ENTRY NAME"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_RIGHT "struct TYPE *elm" "RB_ENTRY NAME"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_PARENT "struct TYPE *elm" "RB_ENTRY NAME"
|
||||
.Fn RB_FOREACH VARNAME NAME "RB_HEAD *head"
|
||||
.Fn RB_FOREACH_REVERSE VARNAME NAME "RB_HEAD *head"
|
||||
.Fn RB_FOREACH "VARNAME" "NAME" "RB_HEAD *head"
|
||||
.Fn RB_FOREACH_SAFE "VARNAME" "NAME" "RB_HEAD *head" "TEMP_VARNAME"
|
||||
.Fn RB_FOREACH_REVERSE "VARNAME" "NAME" "RB_HEAD *head"
|
||||
.Fn RB_FOREACH_REVERSE_SAFE "VARNAME" "NAME" "RB_HEAD *head" "TEMP_VARNAME"
|
||||
.Ft void
|
||||
.Fn RB_INIT "RB_HEAD *head"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_INSERT NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_INSERT "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Ft "struct TYPE *"
|
||||
.Fn RB_REMOVE NAME "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Fn RB_REMOVE "NAME" "RB_HEAD *head" "struct TYPE *elm"
|
||||
.Sh DESCRIPTION
|
||||
These macros define data structures for different types of trees:
|
||||
splay trees and red-black trees.
|
||||
.Pp
|
||||
In the macro definitions,
|
||||
.Fa TYPE
|
||||
is the name tag of a user defined structure that must contain a field of type
|
||||
.Vt SPLAY_ENTRY ,
|
||||
is the name tag of a user defined structure that must contain a field named
|
||||
.Fa FIELD ,
|
||||
of type
|
||||
.Li SPLAY_ENTRY
|
||||
or
|
||||
.Vt RB_ENTRY ,
|
||||
named
|
||||
.Fa ENTRYNAME .
|
||||
.Li RB_ENTRY .
|
||||
The argument
|
||||
.Fa HEADNAME
|
||||
is the name tag of a user defined structure that must be declared
|
||||
using the macros
|
||||
.Fn SPLAY_HEAD ,
|
||||
.Fn SPLAY_HEAD
|
||||
or
|
||||
.Fn RB_HEAD .
|
||||
The argument
|
||||
@ -173,46 +172,38 @@ The argument
|
||||
has to be a unique name prefix for every tree that is defined.
|
||||
.Pp
|
||||
The function prototypes are declared with
|
||||
.Fn SPLAY_PROTOTYPE ,
|
||||
.Fn RB_PROTOTYPE ,
|
||||
.Li SPLAY_PROTOTYPE ,
|
||||
.Li RB_PROTOTYPE ,
|
||||
or
|
||||
.Fn RB_PROTOTYPE_STATIC .
|
||||
.Li RB_PROTOTYPE_STATIC .
|
||||
The function bodies are generated with
|
||||
.Fn SPLAY_GENERATE ,
|
||||
.Fn RB_GENERATE ,
|
||||
.Li SPLAY_GENERATE ,
|
||||
.Li RB_GENERATE ,
|
||||
or
|
||||
.Fn RB_GENERATE_STATIC .
|
||||
.Li RB_GENERATE_STATIC .
|
||||
See the examples below for further explanation of how these macros are used.
|
||||
.Sh SPLAY TREES
|
||||
A splay tree is a self-organizing data structure.
|
||||
Every operation on the tree causes a splay to happen.
|
||||
The splay moves the requested
|
||||
node to the root of the tree and partly rebalances it.
|
||||
The splay moves the requested node to the root of the tree and partly
|
||||
rebalances it.
|
||||
.Pp
|
||||
This has the benefit that request locality causes faster lookups as
|
||||
the requested nodes move to the top of the tree.
|
||||
On the other hand, every lookup causes memory writes.
|
||||
.Pp
|
||||
The Balance Theorem bounds the total access time for
|
||||
.Ar m
|
||||
operations and
|
||||
.Ar n
|
||||
inserts on an initially empty tree as
|
||||
.Fn O "\*[lp]m + n\*[rp]lg n" .
|
||||
The
|
||||
amortized cost for a sequence of
|
||||
.Ar m
|
||||
accesses to a splay tree is
|
||||
.Fn O "lg n" .
|
||||
The Balance Theorem bounds the total access time for m operations
|
||||
and n inserts on an initially empty tree as O((m + n)lg n).
|
||||
The amortized cost for a sequence of m accesses to a splay tree is O(lg n).
|
||||
.Pp
|
||||
A splay tree is headed by a structure defined by the
|
||||
.Fn SPLAY_HEAD
|
||||
macro.
|
||||
A
|
||||
.Fa SPLAY_HEAD
|
||||
structure is declared as follows:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn SPLAY_HEAD HEADNAME TYPE
|
||||
.Va head ;
|
||||
.Bd -literal -offset indent
|
||||
SPLAY_HEAD(HEADNAME, TYPE) head;
|
||||
.Ed
|
||||
.Pp
|
||||
where
|
||||
@ -251,16 +242,15 @@ macro, but should be used only once.
|
||||
Finally,
|
||||
the
|
||||
.Fa CMP
|
||||
argument is the name of a function used to compare tree nodes
|
||||
argument is the name of a function used to compare trees' nodes
|
||||
with each other.
|
||||
The function takes two arguments of type
|
||||
.Vt "struct TYPE *" .
|
||||
.Fa "struct TYPE *" .
|
||||
If the first argument is smaller than the second, the function returns a
|
||||
value smaller than zero.
|
||||
If they are equal, the function returns zero.
|
||||
Otherwise, it should return a value greater than zero.
|
||||
The compare
|
||||
function defines the order of the tree elements.
|
||||
The compare function defines the order of the tree elements.
|
||||
.Pp
|
||||
The
|
||||
.Fn SPLAY_INIT
|
||||
@ -270,11 +260,8 @@ macro initializes the tree referenced by
|
||||
The splay tree can also be initialized statically by using the
|
||||
.Fn SPLAY_INITIALIZER
|
||||
macro like this:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn SPLAY_HEAD HEADNAME TYPE
|
||||
.Va head
|
||||
=
|
||||
.Fn SPLAY_INITIALIZER &head ;
|
||||
.Bd -literal -offset indent
|
||||
SPLAY_HEAD(HEADNAME, TYPE) head = SPLAY_INITIALIZER(&head);
|
||||
.Ed
|
||||
.Pp
|
||||
The
|
||||
@ -282,6 +269,11 @@ The
|
||||
macro inserts the new element
|
||||
.Fa elm
|
||||
into the tree.
|
||||
Upon success,
|
||||
.Va NULL
|
||||
is returned.
|
||||
If a matching element already exists in the tree, the insertion is
|
||||
aborted, and a pointer to the existing element is returned.
|
||||
.Pp
|
||||
The
|
||||
.Fn SPLAY_REMOVE
|
||||
@ -289,6 +281,11 @@ macro removes the element
|
||||
.Fa elm
|
||||
from the tree pointed by
|
||||
.Fa head .
|
||||
Upon success, a pointer to the removed element is returned.
|
||||
.Va NULL
|
||||
is returned if
|
||||
.Fa elm
|
||||
is not present in the tree.
|
||||
.Pp
|
||||
The
|
||||
.Fn SPLAY_FIND
|
||||
@ -296,7 +293,7 @@ macro can be used to find a particular element in the tree.
|
||||
.Bd -literal -offset indent
|
||||
struct TYPE find, *res;
|
||||
find.key = 30;
|
||||
res = SPLAY_FIND(NAME, head, &find);
|
||||
res = SPLAY_FIND(NAME, &head, &find);
|
||||
.Ed
|
||||
.Pp
|
||||
The
|
||||
@ -313,8 +310,8 @@ for (np = SPLAY_MIN(NAME, &head); np != NULL; np = SPLAY_NEXT(NAME, &head, np))
|
||||
Or, for simplicity, one can use the
|
||||
.Fn SPLAY_FOREACH
|
||||
macro:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn SPLAY_FOREACH np NAME head
|
||||
.Bd -literal -offset indent
|
||||
SPLAY_FOREACH(np, NAME, &head)
|
||||
.Ed
|
||||
.Pp
|
||||
The
|
||||
@ -324,29 +321,28 @@ macro should be used to check whether a splay tree is empty.
|
||||
A red-black tree is a binary search tree with the node color as an
|
||||
extra attribute.
|
||||
It fulfills a set of conditions:
|
||||
.Bl -enum -offset indent
|
||||
.Pp
|
||||
.Bl -enum -compact -offset indent
|
||||
.It
|
||||
Every search path from the root to a leaf consists of the same number of
|
||||
black nodes.
|
||||
every search path from the root to a leaf consists of the same number of
|
||||
black nodes,
|
||||
.It
|
||||
Each red node (except for the root) has a black parent.
|
||||
each red node (except for the root) has a black parent,
|
||||
.It
|
||||
Each leaf node is black.
|
||||
each leaf node is black.
|
||||
.El
|
||||
.Pp
|
||||
Every operation on a red-black tree is bounded as
|
||||
.Fn O "lg n" .
|
||||
The maximum height of a red-black tree is
|
||||
.Fn 2lg "n + 1" .
|
||||
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).
|
||||
.Pp
|
||||
A red-black tree is headed by a structure defined by the
|
||||
.Fn RB_HEAD
|
||||
macro.
|
||||
A
|
||||
.Fa RB_HEAD
|
||||
structure is declared as follows:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn RB_HEAD HEADNAME TYPE
|
||||
.Va head ;
|
||||
.Bd -literal -offset indent
|
||||
RB_HEAD(HEADNAME, TYPE) head;
|
||||
.Ed
|
||||
.Pp
|
||||
where
|
||||
@ -364,7 +360,7 @@ their prototypes need to be declared with the
|
||||
.Fn RB_PROTOTYPE
|
||||
or
|
||||
.Fn RB_PROTOTYPE_STATIC
|
||||
macro,
|
||||
macros,
|
||||
where
|
||||
.Fa NAME
|
||||
is a unique identifier for this particular tree.
|
||||
@ -381,7 +377,7 @@ The function bodies are generated with the
|
||||
.Fn RB_GENERATE
|
||||
or
|
||||
.Fn RB_GENERATE_STATIC
|
||||
macro.
|
||||
macros.
|
||||
These macros take the same arguments as the
|
||||
.Fn RB_PROTOTYPE
|
||||
and
|
||||
@ -391,16 +387,15 @@ macros, but should be used only once.
|
||||
Finally,
|
||||
the
|
||||
.Fa CMP
|
||||
argument is the name of a function used to compare tree nodes
|
||||
argument is the name of a function used to compare trees' nodes
|
||||
with each other.
|
||||
The function takes two arguments of type
|
||||
.Vt "struct TYPE *" .
|
||||
.Fa "struct TYPE *" .
|
||||
If the first argument is smaller than the second, the function returns a
|
||||
value smaller than zero.
|
||||
If they are equal, the function returns zero.
|
||||
Otherwise, it should return a value greater than zero.
|
||||
The compare
|
||||
function defines the order of the tree elements.
|
||||
The compare function defines the order of the tree elements.
|
||||
.Pp
|
||||
The
|
||||
.Fn RB_INIT
|
||||
@ -410,11 +405,8 @@ macro initializes the tree referenced by
|
||||
The red-black tree can also be initialized statically by using the
|
||||
.Fn RB_INITIALIZER
|
||||
macro like this:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn RB_HEAD HEADNAME TYPE
|
||||
.Va head
|
||||
=
|
||||
.Fn RB_INITIALIZER &head ;
|
||||
.Bd -literal -offset indent
|
||||
RB_HEAD(HEADNAME, TYPE) head = RB_INITIALIZER(&head);
|
||||
.Ed
|
||||
.Pp
|
||||
The
|
||||
@ -422,6 +414,11 @@ The
|
||||
macro inserts the new element
|
||||
.Fa elm
|
||||
into the tree.
|
||||
Upon success,
|
||||
.Va NULL
|
||||
is returned.
|
||||
If a matching element already exists in the tree, the insertion is
|
||||
aborted, and a pointer to the existing element is returned.
|
||||
.Pp
|
||||
The
|
||||
.Fn RB_REMOVE
|
||||
@ -429,16 +426,24 @@ macro removes the element
|
||||
.Fa elm
|
||||
from the tree pointed by
|
||||
.Fa head .
|
||||
.Fn RB_REMOVE
|
||||
returns
|
||||
.Fa elm .
|
||||
.Pp
|
||||
The
|
||||
.Fn RB_FIND
|
||||
and
|
||||
.Fn RB_NFIND
|
||||
macros can be used to find a particular element in the tree.
|
||||
.Fn RB_FIND
|
||||
finds the node with the same key as
|
||||
.Fa elm .
|
||||
.Fn RB_NFIND
|
||||
finds the first node greater than or equal to the search key.
|
||||
.Bd -literal -offset indent
|
||||
struct TYPE find, *res;
|
||||
find.key = 30;
|
||||
res = RB_FIND(NAME, head, &find);
|
||||
res = RB_FIND(NAME, &head, &find);
|
||||
.Ed
|
||||
.Pp
|
||||
The
|
||||
@ -449,26 +454,119 @@ The
|
||||
and
|
||||
.Fn RB_PREV
|
||||
macros can be used to traverse the tree:
|
||||
.Pp
|
||||
.Dl "for (np = RB_MIN(NAME, &head); np != NULL; np = RB_NEXT(NAME, &head, np))"
|
||||
.Bd -literal -offset indent
|
||||
for (np = RB_MIN(NAME, &head); np != NULL; np = RB_NEXT(NAME, &head, np))
|
||||
.Ed
|
||||
.Pp
|
||||
Or, for simplicity, one can use the
|
||||
.Fn RB_FOREACH
|
||||
or
|
||||
.Fn RB_FOREACH_REVERSE
|
||||
macro:
|
||||
.Bd -ragged -offset indent
|
||||
.Fn RB_FOREACH np NAME head
|
||||
macros:
|
||||
.Bd -literal -offset indent
|
||||
RB_FOREACH(np, NAME, &head)
|
||||
.Ed
|
||||
.Pp
|
||||
The macros
|
||||
.Fn RB_FOREACH_SAFE
|
||||
and
|
||||
.Fn RB_FOREACH_REVERSE_SAFE
|
||||
traverse the tree referenced by head
|
||||
in a forward or reverse direction respectively,
|
||||
assigning each element in turn to np.
|
||||
However, unlike their unsafe counterparts,
|
||||
they permit both the removal of np
|
||||
as well as freeing it from within the loop safely
|
||||
without interfering with the traversal.
|
||||
.Pp
|
||||
The
|
||||
.Fn RB_EMPTY
|
||||
macro should be used to check whether a red-black tree is empty.
|
||||
.Sh EXAMPLES
|
||||
The following example demonstrates how to declare a red-black tree
|
||||
holding integers.
|
||||
Values are inserted into it and the contents of the tree are printed
|
||||
in order.
|
||||
Lastly, the internal structure of the tree is printed.
|
||||
.Bd -literal -offset 3n
|
||||
#include <sys/tree.h>
|
||||
#include <err.h>
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
struct node {
|
||||
RB_ENTRY(node) entry;
|
||||
int i;
|
||||
};
|
||||
|
||||
int intcmp(struct node *, struct node *);
|
||||
void print_tree(struct node *);
|
||||
|
||||
int
|
||||
intcmp(struct node *e1, struct node *e2)
|
||||
{
|
||||
return (e1->i < e2->i ? -1 : e1->i > e2->i);
|
||||
}
|
||||
|
||||
RB_HEAD(inttree, node) head = RB_INITIALIZER(&head);
|
||||
RB_PROTOTYPE(inttree, node, entry, intcmp)
|
||||
RB_GENERATE(inttree, node, entry, intcmp)
|
||||
|
||||
int testdata[] = {
|
||||
20, 16, 17, 13, 3, 6, 1, 8, 2, 4, 10, 19, 5, 9, 12, 15, 18,
|
||||
7, 11, 14
|
||||
};
|
||||
|
||||
void
|
||||
print_tree(struct node *n)
|
||||
{
|
||||
struct node *left, *right;
|
||||
|
||||
if (n == NULL) {
|
||||
printf("nil");
|
||||
return;
|
||||
}
|
||||
left = RB_LEFT(n, entry);
|
||||
right = RB_RIGHT(n, entry);
|
||||
if (left == NULL && right == NULL)
|
||||
printf("%d", n->i);
|
||||
else {
|
||||
printf("%d(", n->i);
|
||||
print_tree(left);
|
||||
printf(",");
|
||||
print_tree(right);
|
||||
printf(")");
|
||||
}
|
||||
}
|
||||
|
||||
int
|
||||
main(void)
|
||||
{
|
||||
int i;
|
||||
struct node *n;
|
||||
|
||||
for (i = 0; i < sizeof(testdata) / sizeof(testdata[0]); i++) {
|
||||
if ((n = malloc(sizeof(struct node))) == NULL)
|
||||
err(1, NULL);
|
||||
n->i = testdata[i];
|
||||
RB_INSERT(inttree, &head, n);
|
||||
}
|
||||
|
||||
RB_FOREACH(n, inttree, &head) {
|
||||
printf("%d\en", n->i);
|
||||
}
|
||||
print_tree(RB_ROOT(&head));
|
||||
printf("\en");
|
||||
return (0);
|
||||
}
|
||||
.Ed
|
||||
.Sh SEE ALSO
|
||||
.Xr queue 3bsd
|
||||
.Sh NOTES
|
||||
Trying to free a tree in the following way is a common error:
|
||||
.Bd -literal -offset indent
|
||||
SPLAY_FOREACH(var, NAME, head) {
|
||||
SPLAY_REMOVE(NAME, head, var);
|
||||
SPLAY_FOREACH(var, NAME, &head) {
|
||||
SPLAY_REMOVE(NAME, &head, var);
|
||||
free(var);
|
||||
}
|
||||
free(head);
|
||||
@ -476,36 +574,17 @@ free(head);
|
||||
.Pp
|
||||
Since
|
||||
.Va var
|
||||
is freed, the
|
||||
is free'd, the
|
||||
.Fn FOREACH
|
||||
macro refers to a pointer that may have been reallocated already.
|
||||
Proper code needs a second variable.
|
||||
.Bd -literal -offset indent
|
||||
for (var = SPLAY_MIN(NAME, head); var != NULL; var = nxt) {
|
||||
nxt = SPLAY_NEXT(NAME, head, var);
|
||||
SPLAY_REMOVE(NAME, head, var);
|
||||
for (var = SPLAY_MIN(NAME, &head); var != NULL; var = nxt) {
|
||||
nxt = SPLAY_NEXT(NAME, &head, var);
|
||||
SPLAY_REMOVE(NAME, &head, var);
|
||||
free(var);
|
||||
}
|
||||
.Ed
|
||||
.Pp
|
||||
Both
|
||||
.Fn RB_INSERT
|
||||
and
|
||||
.Fn SPLAY_INSERT
|
||||
return
|
||||
.Dv NULL
|
||||
if the element was inserted in the tree successfully, otherwise they
|
||||
return a pointer to the element with the colliding key.
|
||||
.Pp
|
||||
Accordingly,
|
||||
.Fn RB_REMOVE
|
||||
and
|
||||
.Fn SPLAY_REMOVE
|
||||
return the pointer to the removed element otherwise they return
|
||||
.Dv NULL
|
||||
to indicate an error.
|
||||
.Sh SEE ALSO
|
||||
.Xr queue 3bsd
|
||||
.Sh AUTHORS
|
||||
The author of the tree macros is
|
||||
.An Niels Provos .
|
||||
|
||||
Loading…
Reference in New Issue
Block a user