1/* $NetBSD: fd_set.h,v 1.8 2024/05/12 10:34:56 rillig Exp $ */
2
3/*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * from: @(#)types.h 8.4 (Berkeley) 1/21/94
32 */
33
34#ifndef _SYS_FD_SET_H_
35#define _SYS_FD_SET_H_
36
37#include <sys/cdefs.h>
38#include <sys/featuretest.h>
39#include <machine/int_types.h>
40
41/*
42 * Implementation dependent defines, hidden from user space.
43 * POSIX does not specify them.
44 */
45
46typedef __uint32_t __fd_mask;
47
48/* 32 = 2 ^ 5 */
49#define __NFDBITS (32)
50#define __NFDSHIFT (5)
51#define __NFDMASK (__NFDBITS - 1)
52
53/*
54 * Select uses bit fields of file descriptors. These macros manipulate
55 * such bit fields. Note: FD_SETSIZE may be defined by the user.
56 */
57
58#ifndef FD_SETSIZE
59#define FD_SETSIZE 256
60#endif
61
62#define __NFD_LEN(a) (((a) + (__NFDBITS - 1)) / __NFDBITS)
63#define __NFD_SIZE __NFD_LEN(FD_SETSIZE)
64#define __NFD_BYTES(a) (__NFD_LEN(a) * sizeof(__fd_mask))
65
66typedef struct fd_set {
67 __fd_mask fds_bits[__NFD_SIZE];
68} fd_set;
69
70#define FD_SET(n, p) \
71 ((p)->fds_bits[(unsigned)(n) >> __NFDSHIFT] |= (1U << ((n) & __NFDMASK)))
72#define FD_CLR(n, p) \
73 ((p)->fds_bits[(unsigned)(n) >> __NFDSHIFT] &= ~(1U << ((n) & __NFDMASK)))
74#define FD_ISSET(n, p) \
75 ((p)->fds_bits[(unsigned)(n) >> __NFDSHIFT] & (1U << ((n) & __NFDMASK)))
76#if __GNUC_PREREQ__(2, 95)
77#define FD_ZERO(p) (void)__builtin_memset((p), 0, sizeof(*(p)))
78#else
79#define FD_ZERO(p) do { \
80 fd_set *__fds = (p); \
81 unsigned int __i; \
82 for (__i = 0; __i < __NFD_SIZE; __i++) \
83 __fds->fds_bits[__i] = 0; \
84 } while (0)
85#endif /* GCC 2.95 */
86
87/*
88 * Expose our internals if we are not required to hide them.
89 */
90#if defined(_NETBSD_SOURCE)
91
92#define fd_mask __fd_mask
93#define NFDBITS __NFDBITS
94
95#if __GNUC_PREREQ__(2, 95)
96#define FD_COPY(f, t) (void)__builtin_memcpy((t), (f), sizeof(*(f)))
97#else
98#define FD_COPY(f, t) do { \
99 fd_set *__f = (f), *__t = (t); \
100 unsigned int __i; \
101 for (__i = 0; __i < __NFD_SIZE; __i++) \
102 __t->fds_bits[__i] = __f->fds_bits[__i]; \
103 } while (0)
104#endif /* GCC 2.95 */
105
106#endif /* _NETBSD_SOURCE */
107
108#endif /* _SYS_FD_SET_H_ */