51 lines
930 B
C
51 lines
930 B
C
|
/* insque(3C) routines
|
||
|
|
This file is in the public domain. */
|
||
|
|
|
||
|
|
/*
|
||
|
|
NAME
|
||
|
|
insque, remque -- insert, remove an element from a queue
|
||
|
|
|
||
|
|
SYNOPSIS
|
||
|
|
struct qelem {
|
||
|
|
struct qelem *q_forw;
|
||
|
|
struct qelem *q_back;
|
||
|
|
char q_data[];
|
||
|
|
};
|
||
|
|
|
||
|
|
void insque (struct qelem *elem, struct qelem *pred)
|
||
|
|
|
||
|
|
void remque (struct qelem *elem)
|
||
|
|
|
||
|
|
DESCRIPTION
|
||
|
|
Routines to manipulate queues built from doubly linked lists.
|
||
|
|
The insque routine inserts ELEM in the queue immediately after
|
||
|
|
PRED. The remque routine removes ELEM from its containing queue.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
struct qelem {
|
||
|
|
struct qelem *q_forw;
|
||
|
|
struct qelem *q_back;
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
void
|
||
|
|
insque (elem, pred)
|
||
|
|
struct qelem *elem;
|
||
|
|
struct qelem *pred;
|
||
|
|
{
|
||
|
|
elem -> q_forw = pred -> q_forw;
|
||
|
|
pred -> q_forw -> q_back = elem;
|
||
|
|
elem -> q_back = pred;
|
||
|
|
pred -> q_forw = elem;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void
|
||
|
|
remque (elem)
|
||
|
|
struct qelem *elem;
|
||
|
|
{
|
||
|
|
elem -> q_forw -> q_back = elem -> q_back;
|
||
|
|
elem -> q_back -> q_forw = elem -> q_forw;
|
||
|
|
}
|