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Add LIST_INSERT_BEFORE and TAILQ_INSERT_BEFORE.

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Change examples to actually free() the nodes removed from lists.
Give examples of faster list deletion routines.
This commit is contained in:
Justin T. Gibbs 1996-01-29 03:23:05 +00:00
parent 7db797deb6
commit 7658b0a216
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=13698
1 changed files with 78 additions and 10 deletions
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88
share/man/man3/queue.3
View file

@ -39,12 +39,14 @@
.Nm LIST_HEAD ,
.Nm LIST_INIT ,
.Nm LIST_INSERT_AFTER ,
.Nm LIST_INSERT_BEFORE ,
.Nm LIST_INSERT_HEAD ,
.Nm LIST_REMOVE ,
.Nm TAILQ_ENTRY ,
.Nm TAILQ_HEAD ,
.Nm TAILQ_INIT ,
.Nm TAILQ_INSERT_AFTER ,
.Nm TAILQ_INSERT_BEFORE ,
.Nm TAILQ_INSERT_HEAD ,
.Nm TAILQ_INSERT_TAIL ,
.Nm TAILQ_REMOVE ,
@ -64,6 +66,7 @@
.Fn LIST_HEAD "HEADNAME" "TYPE"
.Fn LIST_INIT "LIST_HEAD *head"
.Fn LIST_INSERT_AFTER "LIST_ENTRY *listelm" "TYPE *elm" "LIST_ENTRY NAME"
.Fn LIST_INSERT_BEFORE "LIST_ENTRY *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"
.sp
@ -71,6 +74,7 @@
.Fn TAILQ_HEAD "HEADNAME" "TYPE"
.Fn TAILQ_INIT "TAILQ_HEAD *head"
.Fn TAILQ_INSERT_AFTER "TAILQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
.Fn TAILQ_INSERT_BEFORE "TAILQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
.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_REMOVE "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
@ -93,6 +97,8 @@ Insertion of a new entry at the head of the list.
.It
Insertion of a new entry after any element in the list.
.It
Insertion of a new entry before any element in the list.
.It
Removal of any entry in the list.
.It
Forward traversal through the list.
@ -122,8 +128,6 @@ Circular queues add the following functionality:
.It
Entries can be added at the end of a list.
.It
Entries can be added before another entry.
.It
They may be traversed backwards, from tail to head.
.El
However:
@ -216,6 +220,13 @@ 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
@ -228,7 +239,7 @@ struct entry {
...
LIST_ENTRY(entry) entries; /* List. */
...
} *n1, *n2, *np;
} *n1, *n2, *n3, *np;
LIST_INIT(&head); /* Initialize the list. */
@ -237,12 +248,31 @@ LIST_INSERT_HEAD(&head, n1, entries);
n2 = malloc(sizeof(struct entry)); /* Insert after. */
LIST_INSERT_AFTER(n1, n2, entries);
n3 = malloc(sizeof(struct entry)); /* Insert before. */
LIST_INSERT_BEFORE(n2, n3, entries);
LIST_REMOVE(n2, entries); /* Deletion. */
free(n2);
/* Forward traversal. */
for (np = head.lh_first; np != NULL; np = np->entries.le_next)
np-> ...
while (head.lh_first != NULL) /* Delete. */
LIST_REMOVE(head.lh_first, entries);
while (head.lh_first != NULL) { /* List Deletion. */
n1 = head.lh_first;
LIST_REMOVE(n1, entries);
free(n1);
}
n1 = head.lh_first; /* Faster List Delete. */
while (n1 != NULL) {
n2 = n1->entires.le_next;
free(n1);
n1 = n2;
}
LIST_INIT(&head);
.Ed
.Sh TAIL QUEUES
A tail queue is headed by a structure defined by the
@ -308,6 +338,13 @@ 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
@ -320,7 +357,7 @@ struct entry {
...
TAILQ_ENTRY(entry) entries; /* Tail queue. */
...
} *n1, *n2, *np;
} *n1, *n2, *n3, *np;
TAILQ_INIT(&head); /* Initialize the queue. */
@ -332,12 +369,29 @@ TAILQ_INSERT_TAIL(&head, n1, entries);
n2 = malloc(sizeof(struct entry)); /* Insert after. */
TAILQ_INSERT_AFTER(&head, n1, n2, entries);
n3 = malloc(sizeof(struct entry)); /* Insert before. */
TAILQ_INSERT_BEFORE(&head, n2, n3, entries);
TAILQ_REMOVE(&head, n2, entries); /* Deletion. */
free(n2);
/* Forward traversal. */
for (np = head.tqh_first; np != NULL; np = np->entries.tqe_next)
np-> ...
/* Delete. */
while (head.tqh_first != NULL)
/* TailQ Deletion. */
while (head.tqh_first != NULL) {
n1 = head.tqh_first;
TAILQ_REMOVE(&head, head.tqh_first, entries);
free(n1);
}
/* Faster TailQ Deletion. */
n1 = head.tqh_first;
while (n1 != NULL) {
n2 = n1->entries.tqe_next;
free(n1);
n1 = n2;
}
TAILQ_INIT(&head);
.Ed
.Sh CIRCULAR QUEUES
A circular queue is headed by a structure defined by the
@ -438,15 +492,29 @@ CIRCLEQ_INSERT_AFTER(&head, n1, n2, entries);
n2 = malloc(sizeof(struct entry)); /* Insert before. */
CIRCLEQ_INSERT_BEFORE(&head, n1, n2, entries);
CIRCLEQ_REMOVE(&head, n1, entries); /* Deletion. */
free(n1);
/* Forward traversal. */
for (np = head.cqh_first; np != (void *)&head; np = np->entries.cqe_next)
np-> ...
/* Reverse traversal. */
for (np = head.cqh_last; np != (void *)&head; np = np->entries.cqe_prev)
np-> ...
/* Delete. */
while (head.cqh_first != (void *)&head)
/* CircleQ Deletion. */
while (head.cqh_first != (void *)&head) {
n1 = head.cqh_first;
CIRCLEQ_REMOVE(&head, head.cqh_first, entries);
free(n1);
}
/* Faster CircleQ Deletion. */
n1 = head.cqh_first;
while (n1 != (void *)&head) {
n2 = n1->entries.cqh_next;
free(n1);
n1 = n2;
}
CIRCLEQ_INIT(&head);
.Ed
.Sh HISTORY
The