1125 lines
30 KiB
Groff
1125 lines
30 KiB
Groff
.\" $NetBSD: queue.3,v 1.31 2005/01/13 15:13:10 ragge Exp $
|
|
.\"
|
|
.\" Copyright (c) 2000, 2002 The NetBSD Foundation, Inc.
|
|
.\" 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 the NetBSD
|
|
.\" Foundation, Inc. and its contributors.
|
|
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
|
|
.\" contributors may be used to endorse or promote products derived
|
|
.\" from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``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 FOUNDATION OR CONTRIBUTORS
|
|
.\" 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.
|
|
.\"
|
|
.\" Copyright (c) 1993 The Regents of the University of California.
|
|
.\" 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. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
|
.\"
|
|
.\" @(#)queue.3 8.1 (Berkeley) 12/13/93
|
|
.\"
|
|
.Dd April 18, 2004
|
|
.Dt QUEUE 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm SLIST_HEAD ,
|
|
.Nm SLIST_HEAD_INITIALIZER ,
|
|
.Nm SLIST_ENTRY ,
|
|
.Nm SLIST_INIT ,
|
|
.Nm SLIST_INSERT_AFTER ,
|
|
.Nm SLIST_INSERT_HEAD ,
|
|
.Nm SLIST_REMOVE_HEAD ,
|
|
.Nm SLIST_REMOVE ,
|
|
.Nm SLIST_FOREACH ,
|
|
.Nm SLIST_EMPTY ,
|
|
.Nm SLIST_FIRST ,
|
|
.Nm SLIST_NEXT ,
|
|
.Nm SIMPLEQ_HEAD ,
|
|
.Nm SIMPLEQ_HEAD_INITIALIZER ,
|
|
.Nm SIMPLEQ_ENTRY ,
|
|
.Nm SIMPLEQ_INIT ,
|
|
.Nm SIMPLEQ_INSERT_HEAD ,
|
|
.Nm SIMPLEQ_INSERT_TAIL ,
|
|
.Nm SIMPLEQ_INSERT_AFTER ,
|
|
.Nm SIMPLEQ_REMOVE_HEAD ,
|
|
.Nm SIMPLEQ_REMOVE ,
|
|
.Nm SIMPLEQ_FOREACH ,
|
|
.Nm SIMPLEQ_EMPTY ,
|
|
.Nm SIMPLEQ_FIRST ,
|
|
.Nm SIMPLEQ_NEXT ,
|
|
.Nm STAILQ_HEAD ,
|
|
.Nm STAILQ_HEAD_INITIALIZER ,
|
|
.Nm STAILQ_ENTRY ,
|
|
.Nm STAILQ_INIT ,
|
|
.Nm STAILQ_INSERT_HEAD ,
|
|
.Nm STAILQ_INSERT_TAIL ,
|
|
.Nm STAILQ_INSERT_AFTER ,
|
|
.Nm STAILQ_REMOVE_HEAD ,
|
|
.Nm STAILQ_REMOVE ,
|
|
.Nm STAILQ_FOREACH ,
|
|
.Nm STAILQ_EMPTY ,
|
|
.Nm STAILQ_FIRST ,
|
|
.Nm STAILQ_NEXT ,
|
|
.Nm LIST_HEAD ,
|
|
.Nm LIST_HEAD_INITIALIZER ,
|
|
.Nm LIST_ENTRY ,
|
|
.Nm LIST_INIT ,
|
|
.Nm LIST_INSERT_AFTER ,
|
|
.Nm LIST_INSERT_BEFORE ,
|
|
.Nm LIST_INSERT_HEAD ,
|
|
.Nm LIST_REMOVE ,
|
|
.Nm LIST_FOREACH ,
|
|
.Nm LIST_EMPTY ,
|
|
.Nm LIST_FIRST ,
|
|
.Nm LIST_NEXT ,
|
|
.Nm TAILQ_HEAD ,
|
|
.Nm TAILQ_HEAD_INITIALIZER ,
|
|
.Nm TAILQ_ENTRY ,
|
|
.Nm TAILQ_INIT ,
|
|
.Nm TAILQ_INSERT_HEAD ,
|
|
.Nm TAILQ_INSERT_TAIL ,
|
|
.Nm TAILQ_INSERT_AFTER ,
|
|
.Nm TAILQ_INSERT_BEFORE ,
|
|
.Nm TAILQ_REMOVE ,
|
|
.Nm TAILQ_FOREACH ,
|
|
.Nm TAILQ_FOREACH_REVERSE ,
|
|
.Nm TAILQ_EMPTY ,
|
|
.Nm TAILQ_FIRST ,
|
|
.Nm TAILQ_NEXT ,
|
|
.Nm TAILQ_LAST ,
|
|
.Nm TAILQ_PREV ,
|
|
.Nm CIRCLEQ_HEAD ,
|
|
.Nm CIRCLEQ_HEAD_INITIALIZER ,
|
|
.Nm CIRCLEQ_ENTRY ,
|
|
.Nm CIRCLEQ_INIT ,
|
|
.Nm CIRCLEQ_INSERT_AFTER ,
|
|
.Nm CIRCLEQ_INSERT_BEFORE ,
|
|
.Nm CIRCLEQ_INSERT_HEAD ,
|
|
.Nm CIRCLEQ_INSERT_TAIL ,
|
|
.Nm CIRCLEQ_REMOVE ,
|
|
.Nm CIRCLEQ_FOREACH ,
|
|
.Nm CIRCLEQ_FOREACH_REVERSE ,
|
|
.Nm CIRCLEQ_EMPTY ,
|
|
.Nm CIRCLEQ_FIRST ,
|
|
.Nm CIRCLEQ_LAST ,
|
|
.Nm CIRCLEQ_NEXT ,
|
|
.Nm CIRCLEQ_PREV
|
|
.Nd "implementations of singly-linked lists, simple queues, lists, tail queues, and circular queues"
|
|
.Sh SYNOPSIS
|
|
.In sys/queue.h
|
|
.sp
|
|
.Fn SLIST_HEAD "HEADNAME" "TYPE"
|
|
.Fn SLIST_HEAD_INITIALIZER "head"
|
|
.Fn SLIST_ENTRY "TYPE"
|
|
.Fn SLIST_INIT "SLIST_HEAD *head"
|
|
.Fn SLIST_INSERT_AFTER "TYPE *listelm" "TYPE *elm" "SLIST_ENTRY NAME"
|
|
.Fn SLIST_INSERT_HEAD "SLIST_HEAD *head" "TYPE *elm" "SLIST_ENTRY NAME"
|
|
.Fn SLIST_REMOVE_HEAD "SLIST_HEAD *head" "SLIST_ENTRY NAME"
|
|
.Fn SLIST_REMOVE "SLIST_HEAD *head" "TYPE *elm" "TYPE" "SLIST_ENTRY NAME"
|
|
.Fn SLIST_FOREACH "TYPE *var" "SLIST_HEAD *head" "SLIST_ENTRY NAME"
|
|
.Ft int
|
|
.Fn SLIST_EMPTY "SLIST_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn SLIST_FIRST "SLIST_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn SLIST_NEXT "TYPE *elm" "SLIST_ENTRY NAME"
|
|
.sp
|
|
.Fn SIMPLEQ_HEAD "HEADNAME" "TYPE"
|
|
.Fn SIMPLEQ_HEAD_INITIALIZER "head"
|
|
.Fn SIMPLEQ_ENTRY "TYPE"
|
|
.Fn SIMPLEQ_INIT "SIMPLEQ_HEAD *head"
|
|
.Fn SIMPLEQ_INSERT_HEAD "SIMPLEQ_HEAD *head" "TYPE *elm" "SIMPLEQ_ENTRY NAME"
|
|
.Fn SIMPLEQ_INSERT_TAIL "SIMPLEQ_HEAD *head" "TYPE *elm" "SIMPLEQ_ENTRY NAME"
|
|
.Fn SIMPLEQ_INSERT_AFTER "SIMPLEQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "SIMPLEQ_ENTRY NAME"
|
|
.Fn SIMPLEQ_REMOVE_HEAD "SIMPLEQ_HEAD *head" "SIMPLEQ_ENTRY NAME"
|
|
.Fn SIMPLEQ_REMOVE "SIMPLEQ_HEAD *head" "TYPE *elm" "TYPE" "SIMPLEQ_ENTRY NAME"
|
|
.Fn SIMPLEQ_FOREACH "TYPE *var" "SIMPLEQ_HEAD *head" "SIMPLEQ_ENTRY NAME"
|
|
.Ft int
|
|
.Fn SIMPLEQ_EMPTY "SIMPLEQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn SIMPLEQ_FIRST "SIMPLEQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn SIMPLEQ_NEXT "TYPE *elm" "SIMPLEQ_ENTRY NAME"
|
|
.sp
|
|
.Fn STAILQ_HEAD "HEADNAME" "TYPE"
|
|
.Fn STAILQ_HEAD_INITIALIZER "head"
|
|
.Fn STAILQ_ENTRY "TYPE"
|
|
.Fn STAILQ_INIT "STAILQ_HEAD *head"
|
|
.Fn STAILQ_INSERT_HEAD "STAILQ_HEAD *head" "TYPE *elm" "STAILQ_ENTRY NAME"
|
|
.Fn STAILQ_INSERT_TAIL "STAILQ_HEAD *head" "TYPE *elm" "STAILQ_ENTRY NAME"
|
|
.Fn STAILQ_INSERT_AFTER "STAILQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "STAILQ_ENTRY NAME"
|
|
.Fn STAILQ_REMOVE_HEAD "STAILQ_HEAD *head" "STAILQ_ENTRY NAME"
|
|
.Fn STAILQ_REMOVE "STAILQ_HEAD *head" "TYPE *elm" "TYPE" "STAILQ_ENTRY NAME"
|
|
.Fn STAILQ_FOREACH "TYPE *var" "STAILQ_HEAD *head" "STAILQ_ENTRY NAME"
|
|
.Ft int
|
|
.Fn STAILQ_EMPTY "STAILQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn STAILQ_FIRST "STAILQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn STAILQ_NEXT "TYPE *elm" "STAILQ_ENTRY NAME"
|
|
.sp
|
|
.Fn LIST_HEAD "HEADNAME" "TYPE"
|
|
.Fn LIST_HEAD_INITIALIZER "head"
|
|
.Fn LIST_ENTRY "TYPE"
|
|
.Fn LIST_INIT "LIST_HEAD *head"
|
|
.Fn LIST_INSERT_AFTER "TYPE *listelm" "TYPE *elm" "LIST_ENTRY NAME"
|
|
.Fn LIST_INSERT_BEFORE "TYPE *listelm" "TYPE *elm" "LIST_ENTRY NAME"
|
|
.Fn LIST_INSERT_HEAD "LIST_HEAD *head" "TYPE *elm" "LIST_ENTRY NAME"
|
|
.Fn LIST_REMOVE "TYPE *elm" "LIST_ENTRY NAME"
|
|
.Fn LIST_FOREACH "TYPE *var" "LIST_HEAD *head" "LIST_ENTRY NAME"
|
|
.Ft int
|
|
.Fn LIST_EMPTY "LIST_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn LIST_FIRST "LIST_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn LIST_NEXT "TYPE *elm" "LIST_ENTRY NAME"
|
|
.sp
|
|
.Fn TAILQ_HEAD "HEADNAME" "TYPE"
|
|
.Fn TAILQ_HEAD_INITIALIZER "head"
|
|
.Fn TAILQ_ENTRY "TYPE"
|
|
.Fn TAILQ_INIT "TAILQ_HEAD *head"
|
|
.Fn TAILQ_INSERT_HEAD "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_INSERT_TAIL "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_INSERT_AFTER "TAILQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_INSERT_BEFORE "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_REMOVE "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_FOREACH "TYPE *var" "TAILQ_HEAD *head" "TAILQ_ENTRY NAME"
|
|
.Fn TAILQ_FOREACH_REVERSE "TYPE *var" "TAILQ_HEAD *head" "HEADNAME" "TAILQ_ENTRY NAME"
|
|
.Ft int
|
|
.Fn TAILQ_EMPTY "TAILQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn TAILQ_FIRST "TAILQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn TAILQ_NEXT "TYPE *elm" "TAILQ_ENTRY NAME"
|
|
.Ft TYPE *
|
|
.Fn TAILQ_LAST "TAILQ_HEAD *head" "HEADNAME"
|
|
.Ft TYPE *
|
|
.Fn TAILQ_PREV "TYPE *elm" "HEADNAME" "TAILQ_ENTRY NAME"
|
|
.sp
|
|
.Fn CIRCLEQ_HEAD "HEADNAME" "TYPE"
|
|
.Fn CIRCLEQ_HEAD_INITIALIZER "head"
|
|
.Fn CIRCLEQ_ENTRY "TYPE"
|
|
.Fn CIRCLEQ_INIT "CIRCLEQ_HEAD *head"
|
|
.Fn CIRCLEQ_INSERT_AFTER "CIRCLEQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_INSERT_BEFORE "CIRCLEQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_INSERT_HEAD "CIRCLEQ_HEAD *head" "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_INSERT_TAIL "CIRCLEQ_HEAD *head" "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_REMOVE "CIRCLEQ_HEAD *head" "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_FOREACH "TYPE *var" "CIRCLEQ_HEAD *head" "CIRCLEQ_ENTRY NAME"
|
|
.Fn CIRCLEQ_FOREACH_REVERSE "TYPE *var" "CIRCLEQ_HEAD *head" "CIRCLEQ_ENTRY NAME"
|
|
.Ft int
|
|
.Fn CIRCLEQ_EMPTY "CIRCLEQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn CIRCLEQ_FIRST "CIRCLEQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn CIRCLEQ_LAST "CIRCLEQ_HEAD *head"
|
|
.Ft TYPE *
|
|
.Fn CIRCLEQ_NEXT "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Ft TYPE *
|
|
.Fn CIRCLEQ_PREV "TYPE *elm" "CIRCLEQ_ENTRY NAME"
|
|
.Sh DESCRIPTION
|
|
These macros define and operate on five types of data structures:
|
|
singly-linked lists, simple queues, lists, tail queues, and circular queues.
|
|
All five structures support the following functionality:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Insertion of a new entry at the head of the list.
|
|
.It
|
|
Insertion of a new entry before or after any element in the list.
|
|
.It
|
|
Removal of any entry in the list.
|
|
.It
|
|
Forward traversal through the list.
|
|
.El
|
|
.Pp
|
|
Singly-linked lists are the simplest of the five data structures and
|
|
support only the above functionality.
|
|
Singly-linked lists are ideal for applications with large datasets and
|
|
few or no removals,
|
|
or for implementing a LIFO queue.
|
|
.Pp
|
|
Simple queues add the following functionality:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Entries can be added at the end of a list.
|
|
.El
|
|
However:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Entries may not be added before any element in the list.
|
|
.It
|
|
All list insertions and removals must specify the head of the list.
|
|
.It
|
|
Each head entry requires two pointers rather than one.
|
|
.El
|
|
.Pp
|
|
Simple queues are ideal for applications with large datasets and few or
|
|
no removals, or for implementing a FIFO queue.
|
|
.Pp
|
|
All doubly linked types of data structures (lists, tail queues, and circle
|
|
queues) additionally allow:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Insertion of a new entry before any element in the list.
|
|
.It
|
|
O(1) removal of any entry in the list.
|
|
.El
|
|
However:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Each element requires two pointers rather than one.
|
|
.It
|
|
Code size and execution time of operations (except for removal) is about
|
|
twice that of the singly-linked data-structures.
|
|
.El
|
|
.Pp
|
|
Linked lists are the simplest of the doubly linked data structures and
|
|
support only the above functionality over singly-linked lists.
|
|
.Pp
|
|
Tail queues add the following functionality:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Entries can be added at the end of a list.
|
|
.El
|
|
However:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
All list insertions and removals, except insertion before another element, must
|
|
specify the head of the list.
|
|
.It
|
|
Each head entry requires two pointers rather than one.
|
|
.It
|
|
Code size is about 15% greater and operations run about 20% slower
|
|
than lists.
|
|
.El
|
|
.Pp
|
|
Circular queues add the following functionality:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
Entries can be added at the end of a list.
|
|
.It
|
|
They may be traversed backwards, from tail to head.
|
|
.El
|
|
However:
|
|
.Bl -enum -compact -offset indent
|
|
.It
|
|
All list insertions and removals must specify the head of the list.
|
|
.It
|
|
Each head entry requires two pointers rather than one.
|
|
.It
|
|
The termination condition for traversal is more complex.
|
|
.It
|
|
Code size is about 40% greater and operations run about 45% slower
|
|
than lists.
|
|
.El
|
|
.Pp
|
|
In the macro definitions,
|
|
.Fa TYPE
|
|
is the name of a user defined structure,
|
|
that must contain a field of type
|
|
.Li LIST_ENTRY ,
|
|
.Li SIMPLEQ_ENTRY ,
|
|
.Li SLIST_ENTRY ,
|
|
.Li TAILQ_ENTRY ,
|
|
or
|
|
.Li CIRCLEQ_ENTRY ,
|
|
named
|
|
.Fa NAME .
|
|
The argument
|
|
.Fa HEADNAME
|
|
is the name of a user defined structure that must be declared
|
|
using the macros
|
|
.Li LIST_HEAD ,
|
|
.Li SIMPLEQ_HEAD ,
|
|
.Li SLIST_HEAD ,
|
|
.Li TAILQ_HEAD ,
|
|
or
|
|
.Li CIRCLEQ_HEAD .
|
|
See the examples below for further explanation of how these
|
|
macros are used.
|
|
.Sh SINGLY-LINKED LISTS
|
|
A singly-linked list is headed by a structure defined by the
|
|
.Nm SLIST_HEAD
|
|
macro.
|
|
This structure contains a single pointer to the first element
|
|
on the list.
|
|
The elements are singly linked for minimum space and pointer manipulation
|
|
overhead at the expense of O(n) removal for arbitrary elements.
|
|
New elements can be added to the list after an existing element or
|
|
at the head of the list.
|
|
An
|
|
.Fa SLIST_HEAD
|
|
structure is declared as follows:
|
|
.Bd -literal -offset indent
|
|
SLIST_HEAD(HEADNAME, TYPE) head;
|
|
.Ed
|
|
.Pp
|
|
where
|
|
.Fa HEADNAME
|
|
is the name of the structure to be defined, and
|
|
.Fa TYPE
|
|
is the type of the elements to be linked into the list.
|
|
A pointer to the head of the list can later be declared as:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME *headp;
|
|
.Ed
|
|
.Pp
|
|
(The names
|
|
.Li head
|
|
and
|
|
.Li headp
|
|
are user selectable.)
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_HEAD_INITIALIZER
|
|
evaluates to an initializer for the list
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_EMPTY
|
|
evaluates to true if there are no elements in the list.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_ENTRY
|
|
declares a structure that connects the elements in
|
|
the list.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_FIRST
|
|
returns the first element in the list or NULL if the list is empty.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_FOREACH
|
|
traverses the list referenced by
|
|
.Fa head
|
|
in the forward direction, assigning each element in
|
|
turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_INIT
|
|
initializes the list referenced by
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_INSERT_HEAD
|
|
inserts the new element
|
|
.Fa elm
|
|
at the head of the list.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_INSERT_AFTER
|
|
inserts the new element
|
|
.Fa elm
|
|
after the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_NEXT
|
|
returns the next element in the list.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_REMOVE
|
|
removes the element
|
|
.Fa elm
|
|
from the list.
|
|
.Pp
|
|
The macro
|
|
.Nm SLIST_REMOVE_HEAD
|
|
removes the first element from the head of the list.
|
|
For optimum efficiency,
|
|
elements being removed from the head of the list should explicitly use
|
|
this macro instead of the generic
|
|
.Nm SLIST_REMOVE
|
|
macro.
|
|
.Sh SINGLY-LINKED LIST EXAMPLE
|
|
.Bd -literal
|
|
SLIST_HEAD(slisthead, entry) head =
|
|
SLIST_HEAD_INITIALIZER(head);
|
|
struct slisthead *headp; /* Singly-linked List head. */
|
|
struct entry {
|
|
...
|
|
SLIST_ENTRY(entry) entries; /* Singly-linked List. */
|
|
...
|
|
} *n1, *n2, *n3, *np;
|
|
|
|
SLIST_INIT(\*[Am]head); /* Initialize the list. */
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
SLIST_INSERT_HEAD(\*[Am]head, n1, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
SLIST_INSERT_AFTER(n1, n2, entries);
|
|
|
|
SLIST_REMOVE(\*[Am]head, n2, entry, entries);/* Deletion. */
|
|
free(n2);
|
|
|
|
n3 = SLIST_FIRST(\*[Am]head);
|
|
SLIST_REMOVE_HEAD(\*[Am]head, entries); /* Deletion from the head. */
|
|
free(n3);
|
|
/* Forward traversal. */
|
|
SLIST_FOREACH(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
|
|
while (!SLIST_EMPTY(\*[Am]head)) { /* List Deletion. */
|
|
n1 = SLIST_FIRST(\*[Am]head);
|
|
SLIST_REMOVE_HEAD(\*[Am]head, entries);
|
|
free(n1);
|
|
}
|
|
.Ed
|
|
.Sh SIMPLE QUEUES
|
|
A simple queue is headed by a structure defined by the
|
|
.Nm SIMPLEQ_HEAD
|
|
macro.
|
|
This structure contains a pair of pointers,
|
|
one to the first element in the simple queue and the other to
|
|
the last element in the simple queue.
|
|
The elements are singly linked for minimum space and pointer manipulation
|
|
overhead at the expense of O(n) removal for arbitrary elements.
|
|
New elements can be added to the queue after an existing element,
|
|
at the head of the queue, or at the end of the queue.
|
|
A
|
|
.Fa SIMPLEQ_HEAD
|
|
structure is declared as follows:
|
|
.Bd -literal -offset indent
|
|
SIMPLEQ_HEAD(HEADNAME, TYPE) head;
|
|
.Ed
|
|
.sp
|
|
where
|
|
.Li HEADNAME
|
|
is the name of the structure to be defined, and
|
|
.Li TYPE
|
|
is the type of the elements to be linked into the simple queue.
|
|
A pointer to the head of the simple queue can later be declared as:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME *headp;
|
|
.Ed
|
|
.sp
|
|
(The names
|
|
.Li head
|
|
and
|
|
.Li headp
|
|
are user selectable.)
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_ENTRY
|
|
declares a structure that connects the elements in
|
|
the simple queue.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_HEAD_INITIALIZER
|
|
provides a value which can be used to initialize a simple queue head at
|
|
compile time, and is used at the point that the simple queue head
|
|
variable is declared, like:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME head = SIMPLEQ_HEAD_INITIALIZER(head);
|
|
.Ed
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_INIT
|
|
initializes the simple queue referenced by
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_INSERT_HEAD
|
|
inserts the new element
|
|
.Fa elm
|
|
at the head of the simple queue.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_INSERT_TAIL
|
|
inserts the new element
|
|
.Fa elm
|
|
at the end of the simple queue.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_INSERT_AFTER
|
|
inserts the new element
|
|
.Fa elm
|
|
after the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_REMOVE
|
|
removes
|
|
.Fa elm
|
|
from the simple queue.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_REMOVE_HEAD
|
|
removes the first element from the head of the simple queue.
|
|
For optimum efficiency,
|
|
elements being removed from the head of the queue should explicitly use
|
|
this macro instead of the generic
|
|
.Nm SIMPLQ_REMOVE
|
|
macro.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_EMPTY
|
|
return true if the simple queue
|
|
.Fa head
|
|
has no elements.
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_FIRST
|
|
returns the first element of the simple queue
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_FOREACH
|
|
traverses the tail queue referenced by
|
|
.Fa head
|
|
in the forward direction, assigning each element
|
|
in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm SIMPLEQ_NEXT
|
|
returns the element after the element
|
|
.Fa elm .
|
|
.Pp
|
|
The macros prefixed with
|
|
.Dq Nm STAILQ_
|
|
.Nm ( STAILQ_HEAD ,
|
|
.Nm STAILQ_HEAD_INITIALIZER ,
|
|
.Nm STAILQ_ENTRY ,
|
|
.Nm STAILQ_INIT ,
|
|
.Nm STAILQ_INSERT_HEAD ,
|
|
.Nm STAILQ_INSERT_TAIL ,
|
|
.Nm STAILQ_INSERT_AFTER ,
|
|
.Nm STAILQ_REMOVE_HEAD ,
|
|
.Nm STAILQ_REMOVE ,
|
|
.Nm STAILQ_FOREACH ,
|
|
.Nm STAILQ_EMPTY ,
|
|
.Nm STAILQ_FIRST ,
|
|
and
|
|
.Nm STAILQ_NEXT )
|
|
are functionally identical to these simple queue functions,
|
|
and are provided for compatibility with
|
|
.Fx .
|
|
.Sh SIMPLE QUEUE EXAMPLE
|
|
.Bd -literal
|
|
SIMPLEQ_HEAD(simplehead, entry) head;
|
|
struct simplehead *headp; /* Simple queue head. */
|
|
struct entry {
|
|
...
|
|
SIMPLEQ_ENTRY(entry) entries; /* Simple queue. */
|
|
...
|
|
} *n1, *n2, *np;
|
|
|
|
SIMPLEQ_INIT(\*[Am]head); /* Initialize the queue. */
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
SIMPLEQ_INSERT_HEAD(\*[Am]head, n1, entries);
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */
|
|
SIMPLEQ_INSERT_TAIL(\*[Am]head, n1, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
SIMPLEQ_INSERT_AFTER(\*[Am]head, n1, n2, entries);
|
|
/* Forward traversal. */
|
|
SIMPLEQ_FOREACH(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
/* Delete. */
|
|
while (SIMPLEQ_FIRST(\*[Am]head) != NULL)
|
|
SIMPLEQ_REMOVE_HEAD(\*[Am]head, entries);
|
|
if (SIMPLEQ_EMPTY(\*[Am]head)) /* Test for emptiness. */
|
|
printf("nothing to do\\n");
|
|
.Ed
|
|
.Sh LISTS
|
|
A list is headed by a structure defined by the
|
|
.Nm LIST_HEAD
|
|
macro.
|
|
This structure contains a single pointer to the first element
|
|
on the list.
|
|
The elements are doubly linked so that an arbitrary element can be
|
|
removed without traversing the list.
|
|
New elements can be added to the list after an existing element,
|
|
before an existing element, or at the head of the list.
|
|
A
|
|
.Fa LIST_HEAD
|
|
structure is declared as follows:
|
|
.Bd -literal -offset indent
|
|
LIST_HEAD(HEADNAME, TYPE) head;
|
|
.Ed
|
|
.sp
|
|
where
|
|
.Fa HEADNAME
|
|
is the name of the structure to be defined, and
|
|
.Fa TYPE
|
|
is the type of the elements to be linked into the list.
|
|
A pointer to the head of the list can later be declared as:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME *headp;
|
|
.Ed
|
|
.sp
|
|
(The names
|
|
.Li head
|
|
and
|
|
.Li headp
|
|
are user selectable.)
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_ENTRY
|
|
declares a structure that connects the elements in
|
|
the list.
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_HEAD_INITIALIZER
|
|
provides a value which can be used to initialize a list head at
|
|
compile time, and is used at the point that the list head
|
|
variable is declared, like:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME head = LIST_HEAD_INITIALIZER(head);
|
|
.Ed
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_INIT
|
|
initializes the list referenced by
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_INSERT_HEAD
|
|
inserts the new element
|
|
.Fa elm
|
|
at the head of the list.
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_INSERT_AFTER
|
|
inserts the new element
|
|
.Fa elm
|
|
after the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_INSERT_BEFORE
|
|
inserts the new element
|
|
.Fa elm
|
|
before the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_REMOVE
|
|
removes the element
|
|
.Fa elm
|
|
from the list.
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_EMPTY
|
|
return true if the list
|
|
.Fa head
|
|
has no elements.
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_FIRST
|
|
returns the first element of the list
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_FOREACH
|
|
traverses the list referenced by
|
|
.Fa head
|
|
in the forward direction, assigning each element in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm LIST_NEXT
|
|
returns the element after the element
|
|
.Fa elm .
|
|
.Sh LIST EXAMPLE
|
|
.Bd -literal
|
|
LIST_HEAD(listhead, entry) head;
|
|
struct listhead *headp; /* List head. */
|
|
struct entry {
|
|
...
|
|
LIST_ENTRY(entry) entries; /* List. */
|
|
...
|
|
} *n1, *n2, *np;
|
|
|
|
LIST_INIT(\*[Am]head); /* Initialize the list. */
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
LIST_INSERT_HEAD(\*[Am]head, n1, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
LIST_INSERT_AFTER(n1, n2, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert before. */
|
|
LIST_INSERT_BEFORE(n1, n2, entries);
|
|
/* Forward traversal. */
|
|
LIST_FOREACH(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
/* Delete. */
|
|
while (LIST_FIRST(\*[Am]head) != NULL)
|
|
LIST_REMOVE(LIST_FIRST(\*[Am]head), entries);
|
|
if (LIST_EMPTY(\*[Am]head)) /* Test for emptiness. */
|
|
printf("nothing to do\\n");
|
|
.Ed
|
|
.Sh TAIL QUEUES
|
|
A tail queue is headed by a structure defined by the
|
|
.Nm TAILQ_HEAD
|
|
macro.
|
|
This structure contains a pair of pointers,
|
|
one to the first element in the tail queue and the other to
|
|
the last element in the tail queue.
|
|
The elements are doubly linked so that an arbitrary element can be
|
|
removed without traversing the tail queue.
|
|
New elements can be added to the queue after an existing element,
|
|
before an existing element, at the head of the queue, or at the end
|
|
the queue.
|
|
A
|
|
.Fa TAILQ_HEAD
|
|
structure is declared as follows:
|
|
.Bd -literal -offset indent
|
|
TAILQ_HEAD(HEADNAME, TYPE) head;
|
|
.Ed
|
|
.sp
|
|
where
|
|
.Li HEADNAME
|
|
is the name of the structure to be defined, and
|
|
.Li TYPE
|
|
is the type of the elements to be linked into the tail queue.
|
|
A pointer to the head of the tail queue can later be declared as:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME *headp;
|
|
.Ed
|
|
.sp
|
|
(The names
|
|
.Li head
|
|
and
|
|
.Li headp
|
|
are user selectable.)
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_ENTRY
|
|
declares a structure that connects the elements in
|
|
the tail queue.
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_HEAD_INITIALIZER
|
|
provides a value which can be used to initialize a tail queue head at
|
|
compile time, and is used at the point that the tail queue head
|
|
variable is declared, like:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME head = TAILQ_HEAD_INITIALIZER(head);
|
|
.Ed
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_INIT
|
|
initializes the tail queue referenced by
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_INSERT_HEAD
|
|
inserts the new element
|
|
.Fa elm
|
|
at the head of the tail queue.
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_INSERT_TAIL
|
|
inserts the new element
|
|
.Fa elm
|
|
at the end of the tail queue.
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_INSERT_AFTER
|
|
inserts the new element
|
|
.Fa elm
|
|
after the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_INSERT_BEFORE
|
|
inserts the new element
|
|
.Fa elm
|
|
before the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_REMOVE
|
|
removes the element
|
|
.Fa elm
|
|
from the tail queue.
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_EMPTY
|
|
return true if the tail queue
|
|
.Fa head
|
|
has no elements.
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_FIRST
|
|
returns the first element of the tail queue
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_FOREACH
|
|
traverses the tail queue referenced by
|
|
.Fa head
|
|
in the forward direction, assigning each element in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_FOREACH_REVERSE
|
|
traverses the tail queue referenced by
|
|
.Fa head
|
|
in the reverse direction, assigning each element in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm TAILQ_NEXT
|
|
returns the element after the element
|
|
.Fa elm .
|
|
.Sh TAIL QUEUE EXAMPLE
|
|
.Bd -literal
|
|
TAILQ_HEAD(tailhead, entry) head;
|
|
struct tailhead *headp; /* Tail queue head. */
|
|
struct entry {
|
|
...
|
|
TAILQ_ENTRY(entry) entries; /* Tail queue. */
|
|
...
|
|
} *n1, *n2, *np;
|
|
|
|
TAILQ_INIT(\*[Am]head); /* Initialize the queue. */
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
TAILQ_INSERT_HEAD(\*[Am]head, n1, entries);
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */
|
|
TAILQ_INSERT_TAIL(\*[Am]head, n1, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
TAILQ_INSERT_AFTER(\*[Am]head, n1, n2, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert before. */
|
|
TAILQ_INSERT_BEFORE(n1, n2, entries);
|
|
/* Forward traversal. */
|
|
TAILQ_FOREACH(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
/* Reverse traversal. */
|
|
TAILQ_FOREACH_REVERSE(np, \*[Am]head, tailhead, entries)
|
|
np-\*[Gt] ...
|
|
/* Delete. */
|
|
while (TAILQ_FIRST(\*[Am]head) != NULL)
|
|
TAILQ_REMOVE(\*[Am]head, TAILQ_FIRST(\*[Am]head), entries);
|
|
if (TAILQ_EMPTY(\*[Am]head)) /* Test for emptiness. */
|
|
printf("nothing to do\\n");
|
|
.Ed
|
|
.Sh CIRCULAR QUEUES
|
|
A circular queue is headed by a structure defined by the
|
|
.Nm CIRCLEQ_HEAD
|
|
macro.
|
|
This structure contains a pair of pointers,
|
|
one to the first element in the circular queue and the other to the
|
|
last element in the circular queue.
|
|
The elements are doubly linked so that an arbitrary element can be
|
|
removed without traversing the queue.
|
|
New elements can be added to the queue after an existing element,
|
|
before an existing element, at the head of the queue, or at the end
|
|
of the queue.
|
|
A
|
|
.Fa CIRCLEQ_HEAD
|
|
structure is declared as follows:
|
|
.Bd -literal -offset indent
|
|
CIRCLEQ_HEAD(HEADNAME, TYPE) head;
|
|
.Ed
|
|
.sp
|
|
where
|
|
.Li HEADNAME
|
|
is the name of the structure to be defined, and
|
|
.Li TYPE
|
|
is the type of the elements to be linked into the circular queue.
|
|
A pointer to the head of the circular queue can later be declared as:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME *headp;
|
|
.Ed
|
|
.sp
|
|
(The names
|
|
.Li head
|
|
and
|
|
.Li headp
|
|
are user selectable.)
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_ENTRY
|
|
declares a structure that connects the elements in
|
|
the circular queue.
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_HEAD_INITIALIZER
|
|
provides a value which can be used to initialize a circular queue head at
|
|
compile time, and is used at the point that the circular queue head
|
|
variable is declared, like:
|
|
.Bd -literal -offset indent
|
|
struct HEADNAME head = CIRCLEQ_HEAD_INITIALIZER(head);
|
|
.Ed
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_INIT
|
|
initializes the circular queue referenced by
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_INSERT_HEAD
|
|
inserts the new element
|
|
.Fa elm
|
|
at the head of the circular queue.
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_INSERT_TAIL
|
|
inserts the new element
|
|
.Fa elm
|
|
at the end of the circular queue.
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_INSERT_AFTER
|
|
inserts the new element
|
|
.Fa elm
|
|
after the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_INSERT_BEFORE
|
|
inserts the new element
|
|
.Fa elm
|
|
before the element
|
|
.Fa listelm .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_REMOVE
|
|
removes the element
|
|
.Fa elm
|
|
from the circular queue.
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_EMPTY
|
|
return true if the circular queue
|
|
.Fa head
|
|
has no elements.
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_FIRST
|
|
returns the first element of the circular queue
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm CICRLEQ_FOREACH
|
|
traverses the circle queue referenced by
|
|
.Fa head
|
|
in the forward direction, assigning each element in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm CICRLEQ_FOREACH_REVERSE
|
|
traverses the circle queue referenced by
|
|
.Fa head
|
|
in the reverse direction, assigning each element in turn to
|
|
.Fa var .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_LAST
|
|
returns the last element of the circular queue
|
|
.Fa head .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_NEXT
|
|
returns the element after the element
|
|
.Fa elm .
|
|
.Pp
|
|
The macro
|
|
.Nm CIRCLEQ_PREV
|
|
returns the element before the element
|
|
.Fa elm .
|
|
.Sh CIRCULAR QUEUE EXAMPLE
|
|
.Bd -literal
|
|
CIRCLEQ_HEAD(circleq, entry) head;
|
|
struct circleq *headp; /* Circular queue head. */
|
|
struct entry {
|
|
...
|
|
CIRCLEQ_ENTRY(entry) entries; /* Circular queue. */
|
|
...
|
|
} *n1, *n2, *np;
|
|
|
|
CIRCLEQ_INIT(\*[Am]head); /* Initialize the circular queue. */
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
CIRCLEQ_INSERT_HEAD(\*[Am]head, n1, entries);
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */
|
|
CIRCLEQ_INSERT_TAIL(\*[Am]head, n1, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
CIRCLEQ_INSERT_AFTER(\*[Am]head, n1, n2, entries);
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert before. */
|
|
CIRCLEQ_INSERT_BEFORE(\*[Am]head, n1, n2, entries);
|
|
/* Forward traversal. */
|
|
CIRCLEQ_FOREACH(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
/* Reverse traversal. */
|
|
CIRCLEQ_FOREACH_REVERSE(np, \*[Am]head, entries)
|
|
np-\*[Gt] ...
|
|
/* Delete. */
|
|
while (CIRCLEQ_FIRST(\*[Am]head) != (void *)\*[Am]head)
|
|
CIRCLEQ_REMOVE(\*[Am]head, CIRCLEQ_FIRST(\*[Am]head), entries);
|
|
if (CIRCLEQ_EMPTY(\*[Am]head)) /* Test for emptiness. */
|
|
printf("nothing to do\\n");
|
|
.Ed
|
|
.Sh HISTORY
|
|
The
|
|
.Nm queue
|
|
functions first appeared in
|
|
.Bx 4.4 .
|
|
The
|
|
.Nm SIMPLEQ
|
|
functions first appeared in
|
|
.Nx 1.2 .
|
|
The
|
|
.Nm SLIST
|
|
and
|
|
.Nm STAILQ
|
|
functions first appeared in
|
|
.Fx 2.1.5 .
|