libexec/cron/bitstring.h

   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 the above copyright notice and this paragraph are
  10  * duplicated in all such forms and that any documentation,
  11  * advertising materials, and other materials related to such
  12  * distribution and use acknowledge that the software was developed
  13  * by the University of California, Berkeley.  The name of the
  14  * University may not be used to endorse or promote products derived
  15  * from this software without specific prior written permission.
  16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  19  *
  20  *      @(#)bitstring.h 5.2 (Berkeley) 4/4/90
  21  */
  22
  23 typedef unsigned char bitstr_t;
  24
  25 /* internal macros */
  26                                 /* byte of the bitstring bit is in */
  27 #define _bit_byte(bit) \
  28         ((bit) >> 3)
  29
  30                                 /* mask for the bit within its byte */
  31 #define _bit_mask(bit) \
  32         (1 << ((bit)&0x7))
  33
  34 /* external macros */
  35                                 /* bytes in a bitstring of nbits bits */
  36 #define bitstr_size(nbits) \
  37         ((((nbits) - 1) >> 3) + 1)
  38
  39                                 /* allocate a bitstring */
  40 #define bit_alloc(nbits) \
  41         (bitstr_t *)malloc(1, \
  42             (unsigned int)bitstr_size(nbits) * sizeof(bitstr_t))
  43
  44                                 /* allocate a bitstring on the stack */
  45 #define bit_decl(name, nbits) \
  46         (name)[bitstr_size(nbits)]
  47
  48                                 /* is bit N of bitstring name set? */
  49 #define bit_test(name, bit) \
  50         ((name)[_bit_byte(bit)] & _bit_mask(bit))
  51
  52                                 /* set bit N of bitstring name */
  53 #define bit_set(name, bit) \
  54         (name)[_bit_byte(bit)] |= _bit_mask(bit)
  55
  56                                 /* clear bit N of bitstring name */
  57 #define bit_clear(name, bit) \
  58         (name)[_bit_byte(bit)] &= ~_bit_mask(bit)
  59
  60                                 /* clear bits start ... stop in bitstring */
  61 #define bit_nclear(name, start, stop) { \
  62         register bitstr_t *_name = name; \
  63         register int _start = start, _stop = stop; \
  64         register int _startbyte = _bit_byte(_start); \
  65         register int _stopbyte = _bit_byte(_stop); \
  66         if (_startbyte == _stopbyte) { \
  67                 _name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
  68                                       (0xff << ((_stop&0x7) + 1))); \
  69         } else { \
  70                 _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
  71                 while (++_startbyte < _stopbyte) \
  72                         _name[_startbyte] = 0; \
  73                 _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
  74         } \
  75 }
  76
  77                                 /* set bits start ... stop in bitstring */
  78 #define bit_nset(name, start, stop) { \
  79         register bitstr_t *_name = name; \
  80         register int _start = start, _stop = stop; \
  81         register int _startbyte = _bit_byte(_start); \
  82         register int _stopbyte = _bit_byte(_stop); \
  83         if (_startbyte == _stopbyte) { \
  84                 _name[_startbyte] |= ((0xff << (_start&0x7)) & \
  85                                     (0xff >> (7 - (_stop&0x7)))); \
  86         } else { \
  87                 _name[_startbyte] |= 0xff << ((_start)&0x7); \
  88                 while (++_startbyte < _stopbyte) \
  89                         _name[_startbyte] = 0xff; \
  90                 _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
  91         } \
  92 }
  93
  94                                 /* find first bit clear in name */
  95 #define bit_ffc(name, nbits, value) { \
  96         register bitstr_t *_name = name; \
  97         register int _byte, _nbits = nbits; \
  98         register int _stopbyte = _bit_byte(_nbits), _value = -1; \
  99         for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 100                 if (_name[_byte] != 0xff) { \
 101                         _value = _byte << 3; \
 102                         for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
 103                             ++_value, _stopbyte >>= 1); \
 104                         break; \
 105                 } \
 106         *(value) = _value; \
 107 }
 108
 109                                 /* find first bit set in name */
 110 #define bit_ffs(name, nbits, value) { \
 111         register bitstr_t *_name = name; \
 112         register int _byte, _nbits = nbits; \
 113         register int _stopbyte = _bit_byte(_nbits), _value = -1; \
 114         for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 115                 if (_name[_byte]) { \
 116                         _value = _byte << 3; \
 117                         for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
 118                             ++_value, _stopbyte >>= 1); \
 119                         break; \
 120                 } \
 121         *(value) = _value; \
 122 }