xref: /openbsd/lib/libc/stdlib/insque.c (revision 404b540a)
1 /*	$OpenBSD: insque.c,v 1.2 2005/08/08 08:05:36 espie Exp $	*/
2 
3 /*
4  *  Copyright (c) 1993 John Brezak
5  *  All rights reserved.
6  *
7  *  Redistribution and use in source and binary forms, with or without
8  *  modification, are permitted provided that the following conditions
9  *  are met:
10  *  1. Redistributions of source code must retain the above copyright
11  *     notice, this list of conditions and the following disclaimer.
12  *  2. Redistributions in binary form must reproduce the above copyright
13  *     notice, this list of conditions and the following disclaimer in the
14  *     documentation and/or other materials provided with the distribution.
15  *  3. The name of the author may be used to endorse or promote products
16  *     derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
22  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
27  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <search.h>
32 
33 struct qelem {
34         struct qelem *q_forw;
35         struct qelem *q_back;
36 };
37 
38 void
39 insque(void *entry, void *pred)
40 {
41 	struct qelem *e = (struct qelem *) entry;
42 	struct qelem *p = (struct qelem *) pred;
43 
44 	e->q_forw = p->q_forw;
45 	e->q_back = p;
46 	p->q_forw->q_back = e;
47 	p->q_forw = e;
48 }
49