1/*-
 2 * SPDX-License-Identifier: BSD-2-Clause
 3 *
 4 * Copyright (c) 2008, Jeffrey Roberson <jeff@freebsd.org>
 5 * All rights reserved.
 6 *
 7 * Copyright (c) 2008 Nokia Corporation
 8 * All rights reserved.
 9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice unmodified, this list of conditions, and the following
15 *    disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _SYS__BITSET_H_
33#define	_SYS__BITSET_H_
34
35/*
36 * Macros addressing word and bit within it, tuned to make compiler
37 * optimize cases when SETSIZE fits into single machine word.
38 */
39#define	_BITSET_BITS		(sizeof(long) * 8)
40
41#define	__howmany(x, y)	(((x) + ((y) - 1)) / (y))
42
43#define	__bitset_words(_s)	(__howmany(_s, _BITSET_BITS))
44
45#define	__BITSET_DEFINE(_t, _s)						\
46struct _t {								\
47        long    __bits[__bitset_words((_s))];				\
48}
49
50/*
51 * Helper to declare a bitset without it's size being a constant.
52 *
53 * Sadly we cannot declare a bitset struct with 'bits[]', because it's
54 * the only member of the struct and the compiler complains.
55 */
56#define __BITSET_DEFINE_VAR(_t)	__BITSET_DEFINE(_t, 1)
57
58/*
59 * Define a default type that can be used while manually specifying size
60 * to every call.
61 */
62
63#if defined(_KERNEL) || defined(_WANT_FREEBSD_BITSET)
64__BITSET_DEFINE(bitset, 1);
65
66#define	BITSET_DEFINE(_t, _s)	__BITSET_DEFINE(_t, _s)
67#define	BITSET_DEFINE_VAR(_t)	__BITSET_DEFINE_VAR(_t)
68#endif /* defined(_KERNEL) || defined(_WANT_FREEBSD_BITSET) */
69
70#endif /* !_SYS__BITSET_H_ */