1 /* $OpenBSD: lstRequeue.c,v 1.1 2008/01/12 13:05:57 espie Exp $ */
2 /*
3 * Copyright (c) 2008 Marc Espie.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
15 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
18 * PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26 #include "lstInt.h"
27 #include <stdlib.h>
28
29
30 /* Lst_Requeue(l, ln): takes node ln from the list and requeue it at front.
31 */
32 void
Lst_Requeue(Lst l,LstNode ln)33 Lst_Requeue(Lst l, LstNode ln)
34 {
35
36 /* already at front */
37 if (l->firstPtr == ln)
38 return;
39 /* unlink element */
40 if (ln->nextPtr != NULL)
41 ln->nextPtr->prevPtr = ln->prevPtr;
42 if (ln->prevPtr != NULL)
43 ln->prevPtr->nextPtr = ln->nextPtr;
44
45 if (l->lastPtr == ln)
46 l->lastPtr = ln->prevPtr;
47
48 /* relink at front */
49 ln->nextPtr = l->firstPtr;
50 ln->prevPtr = NULL;
51 l->firstPtr->prevPtr = ln;
52 l->firstPtr = ln;
53 }
54
55