-
Notifications
You must be signed in to change notification settings - Fork 17
/
bitstring.3
168 lines (156 loc) · 4.87 KB
/
bitstring.3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
.\" 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. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. 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
.\"
.TH BITSTRING 3 "July 19, 1993"
.SH NAME
\fBbit_alloc\fP,
\fBbit_clear\fP,
\fBbit_decl\fP,
\fBbit_ffs\fP,
\fBbit_nclear\fP,
\fBbit_nset,\fP
\fBbit_set\fP,
\fBbitstr_size\fP,
\fBbit_test\fP
\- bit-string manipulation macros
.SH SYNOPSIS
.nf
\fB#include <bitstring.h>\fP
\f2bitstr_t\f1 \f2*\f1
\fBbit_alloc\fP(\f2int\f1 \f2nbits\f1);
\fBbit_decl\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2nbits\f1);
\fBbit_clear\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2bit\f1);
\fBbit_ffc\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2nbits\f1, \f2int\f1 \f2*value\f1);
\fBbit_ffs\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2nbits\f1, \f2int\f1 \f2*value\f1);
\fBbit_nclear\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2start\f1, \f2int\f1 \f2stop\f1);
\fBbit_nset\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2start\f1, \f2int\f1 \f2stop\f1);
\fBbit_set\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2bit\f1);
\fBbitstr_size\fP(\f2int\f1 \f2nbits\f1);
\fBbit_test\fP(\f2bit_str\f1 \f2name\f1, \f2int\f1 \f2bit\f1);
.fi
.SH DESCRIPTION
These macros operate on strings of bits.
.PP
The macro \fBbit_alloc\fP() returns a pointer of type
``\f2bitstr_t\f1 \f2*\f1'' to sufficient space to store
.I nbits
bits, or NULL if no space is available.
.PP
The macro \fBbit_decl\fP() allocates sufficient space to store
.I nbits
bits on the stack.
.PP
The macro \fBbitstr_size\fP() returns the number of elements of type
.I bitstr_t
necessary to store
.I nbits
bits.
This is useful for copying bit strings.
.PP
The macros
\fBbit_clear\fP()
and
\fBbit_set\fP()
clear or set the zero-based numbered bit
.IR bit ,
in the bit string
.IR name .
.PP
The
\fBbit_nset\fP()
and
\fBbit_nclear\fP()
macros set or clear the zero-based numbered bits from
.I start
to
.I stop
in the bit string
.IR name .
.PP
The
\fBbit_test\fP() macro evaluates to non-zero if the zero-based numbered bit
.I bit
of bit string
.I name
is set, and zero otherwise.
.PP
The \fBbit_ffs\fP() macro stores in the location referenced by
.I value
the zero-based number of the first bit set in the array of
.I nbits
bits referenced by
.IR name .
If no bits are set, the location referenced by
.I value
is set to \-1.
.PP
The macro \fBbit_ffc\fP() stores in the location referenced by
.I value
the zero-based number of the first bit not set in the array of
.I nbits
bits referenced by
.IR name .
If all bits are set, the location referenced by
.I value
is set to \-1.
.PP
The arguments to these macros are evaluated only once and may safely
have side effects.
.SH EXAMPLE
.nf
.in +5
#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);
}
}
.fi
.SH SEE ALSO
malloc(3)