BSD 4_3_Reno release

[unix-history] / usr / src / 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 are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement:  ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
*      @(#)bitstring.h 5.4 (Berkeley) 6/1/90
*/

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) - 1) >> 3) + 1)

                               /* allocate a bitstring */
#define bit_alloc(nbits) \
       (bitstr_t *)calloc(1, \
           (unsigned int)_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; \
       register int _startbyte = _bit_byte(_start); \
       register int _stopbyte = _bit_byte(_stop); \
       _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
       while (++_startbyte < _stopbyte) \
               _name[_startbyte] = 0; \
       _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
}

                               /* set bits start ... stop in bitstring */
#define bit_nset(name, start, stop) { \
       register bitstr_t *_name = name; \
       register int _start = start, _stop = stop; \
       register int _startbyte = _bit_byte(_start); \
       register int _stopbyte = _bit_byte(_stop); \
       _name[_startbyte] |= 0xff << ((start)&0x7); \
       while (++_startbyte < _stopbyte) \
           _name[_startbyte] = 0xff; \
       _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
}

                               /* find first bit clear in name */
#define bit_ffc(name, nbits, value) { \
       register bitstr_t *_name = name; \
       register int _byte, _nbits = nbits; \
       register int _stopbyte = _bit_byte(_nbits), _value = -1; \
       for (_byte = 0; _byte <= _stopbyte; ++_byte) \
               if (_name[_byte] != 0xff) { \
                       _value = _byte << 3; \
                       for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
                           ++_value, _stopbyte >>= 1); \
                       break; \
               } \
       *(value) = _value; \
}

                               /* find first bit set in name */
#define bit_ffs(name, nbits, value) { \
       register bitstr_t *_name = name; \
       register int _byte, _nbits = nbits; \
       register int _stopbyte = _bit_byte(_nbits), _value = -1; \
       for (_byte = 0; _byte <= _stopbyte; ++_byte) \
               if (_name[_byte]) { \
                       _value = _byte << 3; \
                       for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
                           ++_value, _stopbyte >>= 1); \
                       break; \
               } \
       *(value) = _value; \
}