4 * Copyright (c) 1997 FreeBSD, Inc.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer,
12 * verbatim and that no modifications are made prior to this
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY PAUL TRAINA ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL PAUL TRAINA OR HIS KILLER RATS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, LIFE OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 typedef struct _qelement {
34 struct _qelement *q_forw;
35 struct _qelement *q_back;
38 #define INITQUE(Xhead) { \
39 (Xhead).q_forw = &(Xhead); \
40 (Xhead).q_back = &(Xhead); \
43 #define EMPTYQUE(Xhead) \
44 ((Xhead).q_forw == &(Xhead))
46 #define INSQUEUE(elem, pred) { \
47 register qelement *Xe = (qelement *) (elem); \
48 register qelement *Xp = (qelement *) (pred); \
49 Xp->q_forw = (Xe->q_forw = (Xe->q_back = Xp)->q_forw)->q_back = Xe; \
52 #define REMQUE(elem) { \
53 register qelement *Xe = (qelement *) (elem); \
54 (Xe->q_back->q_forw = Xe->q_forw)->q_back = Xe->q_back; \