include/sys/fd_set.h

   1 /*      $NetBSD: fd_set.h,v 1.2 2005/12/11 12:25:20 christos 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 <sys/syslimits.h>
  40 #include <machine/int_types.h>
  41
  42 /*
  43  * Implementation dependent defines, hidden from user space. X/Open does not
  44  * specify them.
  45  */
  46 #define __NBBY          8               /* number of bits in a byte */
  47 typedef __int32_t       __fd_mask;
  48
  49 /* bits per mask */
  50 #define __NFDBITS       ((unsigned int)sizeof(__fd_mask) * __NBBY)
  51
  52 #define __howmany(x, y) (((x) + ((y) - 1)) / (y))
  53
  54 /*
  55  * Select uses bit masks of file descriptors in longs.  These macros
  56  * manipulate such bit fields (the filesystem macros use chars).
  57  * FD_SETSIZE may be defined by the user, but the default here should
  58  * be enough for most uses.
  59  */
  60 #ifndef FD_SETSIZE
  61 #define FD_SETSIZE      __MINIX_OPEN_MAX
  62 #endif
  63
  64 typedef struct fd_set {
  65         __fd_mask       fds_bits[__howmany(FD_SETSIZE, __NFDBITS)];
  66 } fd_set;
  67
  68 #define FD_SET(n, p)    \
  69     ((p)->fds_bits[(n)/__NFDBITS] |= (1 << ((n) % __NFDBITS)))
  70 #define FD_CLR(n, p)    \
  71     ((p)->fds_bits[(n)/__NFDBITS] &= ~(1 << ((n) % __NFDBITS)))
  72 #define FD_ISSET(n, p)  \
  73     ((p)->fds_bits[(n)/__NFDBITS] & (1 << ((n) % __NFDBITS)))
  74 #if __GNUC_PREREQ__(2, 95)
  75 #define FD_ZERO(p)      (void)__builtin_memset((p), 0, sizeof(*(p)))
  76 #else
  77 #define FD_ZERO(p)      do {                                            \
  78         fd_set *__fds = (p);                                            \
  79         unsigned int __i;                                               \
  80         for (__i = 0; __i < __howmany(FD_SETSIZE, __NFDBITS); __i++)    \
  81                 __fds->fds_bits[__i] = 0;                               \
  82         } while (/* CONSTCOND */ 0)
  83 #endif /* GCC 2.95 */
  84
  85 /*
  86  * Expose our internals if we are not required to hide them.
  87  */
  88 #if defined(_NETBSD_SOURCE)
  89
  90 #define fd_mask __fd_mask
  91 #define NFDBITS __NFDBITS
  92 #ifndef howmany
  93 #define howmany(a, b) __howmany(a, b)
  94 #endif
  95
  96 #if __GNUC_PREREQ__(2, 95)
  97 #define FD_COPY(f, t)   (void)__builtin_memcpy((t), (f), sizeof(*(f)))
  98 #else
  99 #define FD_COPY(f, t)   do {                                            \
 100         fd_set *__f = (f), *__t = (t);                                  \
 101         unsigned int __i;                                               \
 102         for (__i = 0; __i < __howmany(FD_SETSIZE, __NFDBITS); __i++)    \
 103                 __t->fds_bits[__i] = __f->fds_bits[__i];                \
 104         } while (/* CONSTCOND */ 0)
 105 #endif /* GCC 2.95 */
 106
 107 #endif /* _NETBSD_SOURCE */
 108
 109 #endif /* _SYS_FD_SET_H_ */