1.\" Copyright (c) 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Paul Vixie. 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)bitstring.3 8.1 (Berkeley) 7/19/93 35.\" $FreeBSD: src/share/man/man3/bitstring.3,v 1.6.2.5 2001/12/17 11:30:11 ru Exp $ 36.\" $DragonFly: src/share/man/man3/bitstring.3,v 1.2 2003/06/17 04:36:58 dillon Exp $ 37.\" 38.Dd July 19, 1993 39.Dt BITSTRING 3 40.Os 41.Sh NAME 42.Nm bit_alloc , 43.Nm bit_clear , 44.Nm bit_decl , 45.Nm bit_ffs , 46.Nm bit_fls , 47.Nm bit_nclear , 48.Nm bit_nset , 49.Nm bit_nsearch , 50.Nm bit_set , 51.Nm bitstr_size , 52.Nm bit_test 53.Nd bit-string manipulation macros 54.Sh SYNOPSIS 55.In bitstring.h 56.Ft bitstr_t * 57.Fn bit_alloc "int nbits" 58.Ft void 59.Fn bit_decl "bitstr_t *name" "int nbits" 60.Ft void 61.Fn bit_clear "bitstr_t *name" "int bit" 62.Ft void 63.Fn bit_ffc "bitstr_t *name" "int nbits" "int *value" 64.Ft void 65.Fn bit_ffs "bitstr_t *name" "int nbits" "int *value" 66.Ft void 67.Fn bit_fls "bitstr_t *name" "int nbits" "int *value" 68.Ft void 69.Fn bit_nclear "bitstr_t *name" "int start" "int stop" 70.Ft void 71.Fn bit_nset "bitstr_t *name" "int start" "int stop" 72.Ft void 73.Fn bit_nsearch "bitstr_t *name" "int nbits" "int *value" "int len" 74.Ft void 75.Fn bit_set "bitstr_t *name" "int bit" 76.Ft int 77.Fn bitstr_size "int nbits" 78.Ft int 79.Fn bit_test "bitstr_t *name" "int bit" 80.Sh DESCRIPTION 81These macros operate on strings of bits. 82.Pp 83The macro 84.Fn bit_alloc 85returns a pointer of type 86.Dq Fa "bitstr_t *" 87to sufficient space to store 88.Fa nbits 89bits, or 90.Dv NULL 91if no space is available. 92.Pp 93The macro 94.Fn bit_decl 95allocates sufficient space to store 96.Fa nbits 97bits on the stack. 98.Pp 99The macro 100.Fn bitstr_size 101returns the number of elements of type 102.Fa bitstr_t 103necessary to store 104.Fa nbits 105bits. 106This is useful for copying bit strings. 107.Pp 108The macros 109.Fn bit_clear 110and 111.Fn bit_set 112clear or set the zero-based numbered bit 113.Fa bit , 114in the bit string 115.Ar name . 116.Pp 117The 118.Fn bit_nset 119and 120.Fn bit_nclear 121macros 122set or clear the zero-based numbered bits from 123.Fa start 124through 125.Fa stop 126in the bit string 127.Ar name . 128.Pp 129The 130.Fn bit_test 131macro 132evaluates to non-zero if the zero-based numbered bit 133.Fa bit 134of bit string 135.Fa name 136is set, and zero otherwise. 137.Pp 138The 139.Fn bit_ffs 140macro 141stores in the location referenced by 142.Fa value 143the zero-based number of the first bit set in the array of 144.Fa nbits 145bits referenced by 146.Fa name . 147If no bits are set, the location referenced by 148.Fa value 149is set to \-1. 150.Pp 151The macro 152.Fn bit_ffc 153stores in the location referenced by 154.Fa value 155the zero-based number of the first bit not set in the array of 156.Fa nbits 157bits referenced by 158.Fa name . 159If all bits are set, the location referenced by 160.Fa value 161is set to \-1. 162.Pp 163The macro 164.Fn bit_fls 165stores in the location referenced by 166.Fa value 167the zero-based number of the highest bit set in array of 168.Fa nbits 169bits referenced by 170.Fa name . 171.Pp 172The macro 173.Fn bit_nsearch 174stores in the location referenced by 175.Fa value 176the zero-based index of a span of clear bits of length 177.Fa len 178in the array of 179.Fa nbits 180bits referenced by 181.Fa name . 182.Pp 183The arguments to these macros are evaluated only once and may safely 184have side effects. 185.Sh EXAMPLES 186.Bd -literal -offset indent 187#include <limits.h> 188#include <bitstring.h> 189 190\&... 191#define LPR_BUSY_BIT 0 192#define LPR_FORMAT_BIT 1 193#define LPR_DOWNLOAD_BIT 2 194\&... 195#define LPR_AVAILABLE_BIT 9 196#define LPR_MAX_BITS 10 197 198make_lpr_available() 199{ 200 bitstr_t bit_decl(bitlist, LPR_MAX_BITS); 201 ... 202 bit_nclear(bitlist, 0, LPR_MAX_BITS - 1); 203 ... 204 if (!bit_test(bitlist, LPR_BUSY_BIT)) { 205 bit_clear(bitlist, LPR_FORMAT_BIT); 206 bit_clear(bitlist, LPR_DOWNLOAD_BIT); 207 bit_set(bitlist, LPR_AVAILABLE_BIT); 208 } 209} 210.Ed 211.Sh SEE ALSO 212.Xr malloc 3 213.Sh HISTORY 214The 215.Nm bitstring 216functions first appeared in 217.Bx 4.4 . 218The 219.Fn bit_fls 220and 221.Fn bit_nsearch 222routines first appeared in 223.Dx 2.9 . 224