The only thing in the our standard source tree that uses this is cron,

[unix-history] / include / bitstring.h

/*
* 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, 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.
*
*      from: @(#)bitstring.h   5.5 (Berkeley) 4/3/91
*      $Id$
*/

#ifndef _BITSTRING_H_
#define _BITSTRING_H_

/* modified for SV/AT and bitstring bugfix by M.R.Murphy, 11oct91
* bitstr_size changed gratuitously, but shorter
* bit_alloc   spelling error fixed
* the following were efficient, but didn't work, they've been made to
* work, but are no longer as efficient :-)
* bit_nclear, bit_nset, bit_ffc, bit_ffs
*/
typedef unsigned char bitstr_t;

/* internal macros */
                               /* byte of the bitstring bit is in */
#define _bit_byte(bit) \
       ((bit) >> 3)

                               /* mask for the bit within its byte */
#define _bit_mask(bit) \
       (1 << ((bit)&0x7))

/* external macros */
                               /* bytes in a bitstring of nbits bits */
#define bitstr_size(nbits) \
       (((nbits) + 7) >> 3)

                               /* allocate a bitstring */
#define bit_alloc(nbits) \
       (bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))

                               /* allocate a bitstring on the stack */
#define bit_decl(name, nbits) \
       (name)[bitstr_size(nbits)]

                               /* is bit N of bitstring name set? */
#define bit_test(name, bit) \
       ((name)[_bit_byte(bit)] & _bit_mask(bit))

                               /* set bit N of bitstring name */
#define bit_set(name, bit) \
       (name)[_bit_byte(bit)] |= _bit_mask(bit)

                               /* clear bit N of bitstring name */
#define bit_clear(name, bit) \
       (name)[_bit_byte(bit)] &= ~_bit_mask(bit)

                               /* clear bits start ... stop in bitstring */
#define bit_nclear(name, start, stop) { \
       register bitstr_t *_name = name; \
       register int _start = start, _stop = stop; \
       while (_start <= _stop) { \
               bit_clear(_name, _start); \
               _start++; \
               } \
}

                               /* set bits start ... stop in bitstring */
#define bit_nset(name, start, stop) { \
       register bitstr_t *_name = name; \
       register int _start = start, _stop = stop; \
       while (_start <= _stop) { \
               bit_set(_name, _start); \
               _start++; \
               } \
}

                               /* find first bit clear in name */
#define bit_ffc(name, nbits, value) { \
       register bitstr_t *_name = name; \
       register int _bit, _nbits = nbits, _value = -1; \
       for (_bit = 0; _bit < _nbits; ++_bit) \
               if (!bit_test(_name, _bit)) { \
                       _value = _bit; \
                       break; \
               } \
       *(value) = _value; \
}

                               /* find first bit set in name */
#define bit_ffs(name, nbits, value) { \
       register bitstr_t *_name = name; \
       register int _bit, _nbits = nbits, _value = -1; \
       for (_bit = 0; _bit < _nbits; ++_bit) \
               if (bit_test(_name, _bit)) { \
                       _value = _bit; \
                       break; \
               } \
       *(value) = _value; \
}

#endif /* !_BITSTRING_H_ */