mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-07 13:54:33 +00:00
51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
|
/* insque(3C) routines
|
||
|
This file is in the public domain. */
|
||
|
|
||
|
/*
|
||
|
|
||
|
@deftypefn Supplemental void insque (struct qelem *@var{elem}, struct qelem *@var{pred})
|
||
|
@deftypefnx Supplemental void remque (struct qelem *@var{elem})
|
||
|
|
||
|
Routines to manipulate queues built from doubly linked lists. The
|
||
|
@code{insque} routine inserts @var{elem} in the queue immediately
|
||
|
after @var{pred}. The @code{remque} routine removes @var{elem} from
|
||
|
its containing queue. These routines expect to be passed pointers to
|
||
|
structures which have as their first members a forward pointer and a
|
||
|
back pointer, like this prototype (although no prototype is provided):
|
||
|
|
||
|
@example
|
||
|
struct qelem @{
|
||
|
struct qelem *q_forw;
|
||
|
struct qelem *q_back;
|
||
|
char q_data[];
|
||
|
@};
|
||
|
@end example
|
||
|
|
||
|
@end deftypefn
|
||
|
|
||
|
*/
|
||
|
|
||
|
|
||
|
struct qelem {
|
||
|
struct qelem *q_forw;
|
||
|
struct qelem *q_back;
|
||
|
};
|
||
|
|
||
|
|
||
|
void
|
||
|
insque (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 (struct qelem *elem)
|
||
|
{
|
||
|
elem -> q_forw -> q_back = elem -> q_back;
|
||
|
elem -> q_back -> q_forw = elem -> q_forw;
|
||
|
}
|