1 /******************************************************************************
3 * Copyright (C) 2002 Jason Evans <jasone@FreeBSD.org>.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice(s), this list of conditions and the following disclaimer
11 * unmodified other than the allowable addition of one or more
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice(s), this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
25 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
27 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
28 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 ******************************************************************************/
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 /* Ring definitions. */
46 #define qr_new(a_qr, a_field) do { \
47 (a_qr)->a_field.qre_next = (a_qr); \
48 (a_qr)->a_field.qre_prev = (a_qr); \
51 #define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next)
53 #define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev)
55 #define qr_before_insert(a_qrelm, a_qr, a_field) do { \
56 (a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev; \
57 (a_qr)->a_field.qre_next = (a_qrelm); \
58 (a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr); \
59 (a_qrelm)->a_field.qre_prev = (a_qr); \
62 #define qr_after_insert(a_qrelm, a_qr, a_field) \
65 (a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next; \
66 (a_qr)->a_field.qre_prev = (a_qrelm); \
67 (a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr); \
68 (a_qrelm)->a_field.qre_next = (a_qr); \
71 #define qr_meld(a_qr_a, a_qr_b, a_field) do { \
73 (a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b); \
74 (a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a); \
75 t = (a_qr_a)->a_field.qre_prev; \
76 (a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev; \
77 (a_qr_b)->a_field.qre_prev = t; \
80 /* qr_meld() and qr_split() are functionally equivalent, so there's no need to
81 * have two copies of the code. */
82 #define qr_split(a_qr_a, a_qr_b, a_field) \
83 qr_meld((a_qr_a), (a_qr_b), a_field)
85 #define qr_remove(a_qr, a_field) do { \
86 (a_qr)->a_field.qre_prev->a_field.qre_next \
87 = (a_qr)->a_field.qre_next; \
88 (a_qr)->a_field.qre_next->a_field.qre_prev \
89 = (a_qr)->a_field.qre_prev; \
90 (a_qr)->a_field.qre_next = (a_qr); \
91 (a_qr)->a_field.qre_prev = (a_qr); \
94 #define qr_foreach(var, a_qr, a_field) \
95 for ((var) = (a_qr); \
97 (var) = (((var)->a_field.qre_next != (a_qr)) \
98 ? (var)->a_field.qre_next : NULL))
100 #define qr_reverse_foreach(var, a_qr, a_field) \
101 for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL; \
103 (var) = (((var) != (a_qr)) \
104 ? (var)->a_field.qre_prev : NULL))