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Annotation of 43BSDReno/include/bitstring.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Paul Vixie.
                      7:  *
                      8:  * Redistribution and use in source and binary forms are permitted
                      9:  * provided that: (1) source distributions retain this entire copyright
                     10:  * notice and comment, and (2) distributions including binaries display
                     11:  * the following acknowledgement:  ``This product includes software
                     12:  * developed by the University of California, Berkeley and its contributors''
                     13:  * in the documentation or other materials provided with the distribution
                     14:  * and in all advertising materials mentioning features or use of this
                     15:  * software. Neither the name of the University nor the names of its
                     16:  * contributors may be used to endorse or promote products derived
                     17:  * from this software without specific prior written permission.
                     18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     19:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     20:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     21:  *
                     22:  *     @(#)bitstring.h 5.4 (Berkeley) 6/1/90
                     23:  */
                     24: 
                     25: typedef        unsigned char bitstr_t;
                     26: 
                     27: /* internal macros */
                     28:                                /* byte of the bitstring bit is in */
                     29: #define        _bit_byte(bit) \
                     30:        ((bit) >> 3)
                     31: 
                     32:                                /* mask for the bit within its byte */
                     33: #define        _bit_mask(bit) \
                     34:        (1 << ((bit)&0x7))
                     35: 
                     36: /* external macros */
                     37:                                /* bytes in a bitstring of nbits bits */
                     38: #define        bitstr_size(nbits) \
                     39:        ((((nbits) - 1) >> 3) + 1)
                     40: 
                     41:                                /* allocate a bitstring */
                     42: #define        bit_alloc(nbits) \
                     43:        (bitstr_t *)calloc(1, \
                     44:            (unsigned int)_bitstr_size(nbits) * sizeof(bitstr_t))
                     45: 
                     46:                                /* allocate a bitstring on the stack */
                     47: #define        bit_decl(name, nbits) \
                     48:        (name)[bitstr_size(nbits)]
                     49: 
                     50:                                /* is bit N of bitstring name set? */
                     51: #define        bit_test(name, bit) \
                     52:        ((name)[_bit_byte(bit)] & _bit_mask(bit))
                     53: 
                     54:                                /* set bit N of bitstring name */
                     55: #define        bit_set(name, bit) \
                     56:        (name)[_bit_byte(bit)] |= _bit_mask(bit)
                     57: 
                     58:                                /* clear bit N of bitstring name */
                     59: #define        bit_clear(name, bit) \
                     60:        (name)[_bit_byte(bit)] &= ~_bit_mask(bit)
                     61: 
                     62:                                /* clear bits start ... stop in bitstring */
                     63: #define        bit_nclear(name, start, stop) { \
                     64:        register bitstr_t *_name = name; \
                     65:        register int _start = start, _stop = stop; \
                     66:        register int _startbyte = _bit_byte(_start); \
                     67:        register int _stopbyte = _bit_byte(_stop); \
                     68:        _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
                     69:        while (++_startbyte < _stopbyte) \
                     70:                _name[_startbyte] = 0; \
                     71:        _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
                     72: }
                     73: 
                     74:                                /* set bits start ... stop in bitstring */
                     75: #define        bit_nset(name, start, stop) { \
                     76:        register bitstr_t *_name = name; \
                     77:        register int _start = start, _stop = stop; \
                     78:        register int _startbyte = _bit_byte(_start); \
                     79:        register int _stopbyte = _bit_byte(_stop); \
                     80:        _name[_startbyte] |= 0xff << ((start)&0x7); \
                     81:        while (++_startbyte < _stopbyte) \
                     82:            _name[_startbyte] = 0xff; \
                     83:        _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
                     84: }
                     85: 
                     86:                                /* find first bit clear in name */
                     87: #define        bit_ffc(name, nbits, value) { \
                     88:        register bitstr_t *_name = name; \
                     89:        register int _byte, _nbits = nbits; \
                     90:        register int _stopbyte = _bit_byte(_nbits), _value = -1; \
                     91:        for (_byte = 0; _byte <= _stopbyte; ++_byte) \
                     92:                if (_name[_byte] != 0xff) { \
                     93:                        _value = _byte << 3; \
                     94:                        for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
                     95:                            ++_value, _stopbyte >>= 1); \
                     96:                        break; \
                     97:                } \
                     98:        *(value) = _value; \
                     99: }
                    100: 
                    101:                                /* find first bit set in name */
                    102: #define        bit_ffs(name, nbits, value) { \
                    103:        register bitstr_t *_name = name; \
                    104:        register int _byte, _nbits = nbits; \
                    105:        register int _stopbyte = _bit_byte(_nbits), _value = -1; \
                    106:        for (_byte = 0; _byte <= _stopbyte; ++_byte) \
                    107:                if (_name[_byte]) { \
                    108:                        _value = _byte << 3; \
                    109:                        for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
                    110:                            ++_value, _stopbyte >>= 1); \
                    111:                        break; \
                    112:                } \
                    113:        *(value) = _value; \
                    114: }

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