_bitset.h revision 331722 
1/*-
2 * Copyright (c) 2008, Jeffrey Roberson <jeff@freebsd.org>
3 * All rights reserved.
4 *
5 * Copyright (c) 2008 Nokia Corporation
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
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.
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 WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/sys/sys/_bitset.h 331722 2018-03-29 02:50:57Z eadler $
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#endif /* !_SYS__BITSET_H_ */
59