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Diffstat (limited to 'share/man/man3/bit_alloc.3')
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diff --git a/share/man/man3/bit_alloc.3 b/share/man/man3/bit_alloc.3 new file mode 100644 index 00000000000..7b15b2b2105 --- /dev/null +++ b/share/man/man3/bit_alloc.3 @@ -0,0 +1,175 @@ +.\" $OpenBSD: bit_alloc.3,v 1.1 2019/08/30 18:33:17 deraadt Exp $ +.\" $NetBSD: bitstring.3,v 1.4 1994/11/30 15:24:31 jtc Exp $ +.\" +.\" Copyright (c) 1989, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Paul Vixie. +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)bitstring.3 8.1 (Berkeley) 7/19/93 +.\" +.Dd $Mdocdate: August 30 2019 $ +.Dt BIT_ALLOC 3 +.Os +.Sh NAME +.Nm bit_alloc , +.Nm bit_clear , +.Nm bit_decl , +.Nm bit_ffc , +.Nm bit_ffs , +.Nm bit_nclear , +.Nm bit_nset , +.Nm bit_set , +.Nm bitstr_size , +.Nm bit_test +.Nd bit-string manipulation macros +.Sh SYNOPSIS +.In bitstring.h +.Ft bitstr_t * +.Fn bit_alloc "int nbits" +.Fn bit_clear "bit_str name" "int bit" +.Fn bit_decl "bit_str name" "int nbits" +.Fn bit_ffc "bit_str name" "int nbits" "int *value" +.Fn bit_ffs "bit_str name" "int nbits" "int *value" +.Fn bit_nclear "bit_str name" "int start" "int stop" +.Fn bit_nset "bit_str name" "int start" "int stop" +.Fn bit_set "bit_str name" "int bit" +.Fn bitstr_size "int nbits" +.Fn bit_test "bit_str name" "int bit" +.Sh DESCRIPTION +These macros operate on strings of bits. +.Pp +The +.Fn bit_alloc +macro returns a pointer of type +.Li "bitstr_t *" +to sufficient space to store +.Fa nbits +bits, or +.Dv NULL +if no space is available. +.Pp +The +.Fn bit_decl +macro allocates sufficient space to store +.Fa nbits +bits on the stack. +.Pp +The +.Fn bitstr_size +macro returns the number of elements of type +.Li bitstr_t +necessary to store +.Fa nbits +bits. +This is useful for copying bit strings. +.Pp +The +.Fn bit_clear +and +.Fn bit_set +macros clear or set the zero-based numbered bit +.Fa bit , +in the bit string +.Ar name . +.Pp +The +.Fn bit_nclear +and +.Fn bit_nset +macros clear or set the zero-based numbered bits from +.Fa start +to +.Fa stop +in the bit string +.Ar name . +.Pp +The +.Fn bit_test +macro evaluates to non-zero if the zero-based numbered bit +.Fa bit +of bit string +.Fa name +is set, and zero otherwise. +.Pp +The +.Fn bit_ffs +macro stores in the location referenced by +.Fa value +the zero-based number of the first bit set in the array of +.Fa nbits +bits referenced by +.Fa name . +If no bits are set, the location referenced by +.Fa value +is set to \-1. +.Pp +The +.Fn bit_ffc +macro stores in the location referenced by +.Fa value +the zero-based number of the first bit not set in the array of +.Fa nbits +bits referenced by +.Fa name . +If all bits are set, the location referenced by +.Fa value +is set to \-1. +.Pp +The arguments to these macros are evaluated only once and may safely +have side effects. +.Sh EXAMPLES +.Bd -literal -offset indent +#include <limits.h> +#include <bitstring.h> + +\&... +#define LPR_BUSY_BIT 0 +#define LPR_FORMAT_BIT 1 +#define LPR_DOWNLOAD_BIT 2 +\&... +#define LPR_AVAILABLE_BIT 9 +#define LPR_MAX_BITS 10 + +make_lpr_available() +{ + bitstr_t bit_decl(bitlist, LPR_MAX_BITS); + ... + bit_nclear(bitlist, 0, LPR_MAX_BITS - 1); + ... + if (!bit_test(bitlist, LPR_BUSY_BIT)) { + bit_clear(bitlist, LPR_FORMAT_BIT); + bit_clear(bitlist, LPR_DOWNLOAD_BIT); + bit_set(bitlist, LPR_AVAILABLE_BIT); + } +} +.Ed +.Sh SEE ALSO +.Xr malloc 3 +.Sh HISTORY +These functions first appeared in +.Bx 4.4 . |