pkg-cron/trunk/bitstring.3

.\" Copyright (c) 1989 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 are permitted
.\" provided that the above copyright notice and this paragraph are
.\" duplicated in all such forms and that any documentation,
.\" advertising materials, and other materials related to such
.\" distribution and use acknowledge that the software was developed
.\" by the University of California, Berkeley.  The name of the
.\" University may not be used to endorse or promote products derived
.\" from this software without specific prior written permission.
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
.\"
.\"     @(#)bitstring.3 5.1 (Berkeley) 12/13/89
.\"
.TH BITSTRING 3  "December 13, 1989"
.UC 4
.SH NAME
bit_alloc, bit_clear, bit_decl, bit_ffs, bit_nclear, bit_nset,
bit_set, bitstr_size, bit_test \- bit-string manipulation macros
.SH SYNOPSIS
.ft B
.nf
#include <bitstring.h>

name = bit_alloc(nbits)
bitstr_t *name;
int nbits;

bit_decl(name, nbits)
bitstr_t name;
int nbits;

bit_clear(name, bit)
bitstr_t name;
int bit;

bit_ffc(name, nbits, value)
bitstr_t name;
int nbits, *value;

bit_ffs(name, nbits, value)
bitstr_t name;
int nbits, *value;

bit_nclear(name, start, stop)
bitstr_t name;
int start, stop;

bit_nset(name, start, stop)
bitstr_t name;
int start, stop;

bit_set(name, bit)
bitstr_t name;
int bit;

bitstr_size(nbits)
int nbits;

bit_test(name, bit)
bitstr_t name;
int bit;
.fi
.ft R
.SH DESCRIPTION
These macros operate on strings of bits.
.PP
.I Bit_alloc
returns a pointer of type
.I bitstr_t\ *
to sufficient space to store
.I nbits
bits, or NULL if no space is available.
.PP
.I Bit_decl
is a macro for allocating sufficient space to store
.I nbits
bits on the stack.
.PP
.I Bitstr_size
returns the number of elements of type
.I bitstr_t
necessary to store
.I nbits
bits.
This is useful for copying bit strings.
.PP
.I Bit_clear
and
.I bit_set
clear or set the zero-based numbered bit
.IR bit ,
in the bit string
.IR name .
.PP
.I Bit_nset
and
.I bit_nclear
set or clear the zero-based numbered bits from
.I start
to
.I stop
in the bit string
.IR name .
.PP
.I Bit_test
evaluates to zero if the zero-based numbered bit
.I bit
of bit string
.I name
is set, and non-zero otherwise.
.PP
.I Bit_ffs
sets
.I *value
to 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,
.I *value
is set to -1.
.PP
.I Bit_ffc
sets
.I *value
to 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,
.I value
is set to -1.
.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)
1	.\" Copyright (c) 1989 The Regents of the University of California.
2	.\" All rights reserved.
3	.\"
4	.\" This code is derived from software contributed to Berkeley by
5	.\" Paul Vixie.
6	.\"
7	.\" Redistribution and use in source and binary forms are permitted
8	.\" provided that the above copyright notice and this paragraph are
9	.\" duplicated in all such forms and that any documentation,
10	.\" advertising materials, and other materials related to such
11	.\" distribution and use acknowledge that the software was developed
12	.\" by the University of California, Berkeley. The name of the
13	.\" University may not be used to endorse or promote products derived
14	.\" from this software without specific prior written permission.
15	.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
16	.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
17	.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
18	.\"
19	.\" @(#)bitstring.3 5.1 (Berkeley) 12/13/89
20	.\"
21	.TH BITSTRING 3 "December 13, 1989"
22	.UC 4
23	.SH NAME
24	bit_alloc, bit_clear, bit_decl, bit_ffs, bit_nclear, bit_nset,
25	bit_set, bitstr_size, bit_test \- bit-string manipulation macros
26	.SH SYNOPSIS
27	.ft B
28	.nf
29	#include <bitstring.h>
30
31	name = bit_alloc(nbits)
32	bitstr_t *name;
33	int nbits;
34
35	bit_decl(name, nbits)
36	bitstr_t name;
37	int nbits;
38
39	bit_clear(name, bit)
40	bitstr_t name;
41	int bit;
42
43	bit_ffc(name, nbits, value)
44	bitstr_t name;
45	int nbits, *value;
46
47	bit_ffs(name, nbits, value)
48	bitstr_t name;
49	int nbits, *value;
50
51	bit_nclear(name, start, stop)
52	bitstr_t name;
53	int start, stop;
54
55	bit_nset(name, start, stop)
56	bitstr_t name;
57	int start, stop;
58
59	bit_set(name, bit)
60	bitstr_t name;
61	int bit;
62
63	bitstr_size(nbits)
64	int nbits;
65
66	bit_test(name, bit)
67	bitstr_t name;
68	int bit;
69	.fi
70	.ft R
71	.SH DESCRIPTION
72	These macros operate on strings of bits.
73	.PP
74	.I Bit_alloc
75	returns a pointer of type
76	.I bitstr_t\ *
77	to sufficient space to store
78	.I nbits
79	bits, or NULL if no space is available.
80	.PP
81	.I Bit_decl
82	is a macro for allocating sufficient space to store
83	.I nbits
84	bits on the stack.
85	.PP
86	.I Bitstr_size
87	returns the number of elements of type
88	.I bitstr_t
89	necessary to store
90	.I nbits
91	bits.
92	This is useful for copying bit strings.
93	.PP
94	.I Bit_clear
95	and
96	.I bit_set
97	clear or set the zero-based numbered bit
98	.IR bit ,
99	in the bit string
100	.IR name .
101	.PP
102	.I Bit_nset
103	and
104	.I bit_nclear
105	set or clear the zero-based numbered bits from
106	.I start
107	to
108	.I stop
109	in the bit string
110	.IR name .
111	.PP
112	.I Bit_test
113	evaluates to zero if the zero-based numbered bit
114	.I bit
115	of bit string
116	.I name
117	is set, and non-zero otherwise.
118	.PP
119	.I Bit_ffs
120	sets
121	.I *value
122	to the zero-based number of the first bit set in the array of
123	.I nbits
124	bits referenced by
125	.IR name .
126	If no bits are set,
127	.I *value
128	is set to -1.
129	.PP
130	.I Bit_ffc
131	sets
132	.I *value
133	to the zero-based number of the first bit not set in the array of
134	.I nbits
135	bits referenced by
136	.IR name .
137	If all bits are set,
138	.I value
139	is set to -1.
140	.SH EXAMPLE
141	.nf
142	.in +5
143	#include <limits.h>
144	#include <bitstring.h>
145
146	...
147	#define LPR_BUSY_BIT 0
148	#define LPR_FORMAT_BIT 1
149	#define LPR_DOWNLOAD_BIT 2
150	...
151	#define LPR_AVAILABLE_BIT 9
152	#define LPR_MAX_BITS 10
153
154	make_lpr_available()
155	{
156	bitstr_t bit_decl(bitlist, LPR_MAX_BITS);
157	...
158	bit_nclear(bitlist, 0, LPR_MAX_BITS - 1);
159	...
160	if (!bit_test(bitlist, LPR_BUSY_BIT)) {
161	bit_clear(bitlist, LPR_FORMAT_BIT);
162	bit_clear(bitlist, LPR_DOWNLOAD_BIT);
163	bit_set(bitlist, LPR_AVAILABLE_BIT);
164	}
165	}
166	.fi
167	.SH "SEE ALSO"
168	malloc(3)