1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
########################################################################
##
## Copyright (C) 2004-2024 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {@var{C} =} bitcmp (@var{A}, @var{k})
## Return the @var{k}-bit complement of integers in @var{A}.
##
## If @var{k} is omitted @code{k = log2 (flintmax) + 1} is assumed.
##
## @example
## @group
## bitcmp (7,4)
## @result{} 8
## dec2bin (11)
## @result{} 1011
## dec2bin (bitcmp (11, 6))
## @result{} 110100
## @end group
## @end example
##
## @seealso{bitand, bitor, bitxor, bitset, bitget, bitcmp, bitshift, flintmax}
## @end deftypefn
## Liberally based on the version by Kai Habel from Octave Forge
function C = bitcmp (A, k)
if (nargin < 1)
print_usage ();
endif
if (nargin == 2 && (! isscalar (k) || (floor (k) != k)))
error ("bitcmp: K must be a scalar integer");
endif
if (isa (A, "double"))
bmax = flintmax - 1;
amax = ceil (log2 (bmax));
elseif (isa (A, "single"))
bmax = flintmax ("single") - 1;
amax = ceil (log2 (bmax));
elseif (isinteger (A))
amax = sizeof (ones (1, class (A))) * 8;
bmax = bitpack (true (amax, 1), class (A));
else
error ("bitcmp: invalid class %s", class (A));
endif
if (nargin == 1 || k == amax)
C = bitxor (A, bmax);
else
m = double (k);
if (any (m < 1) || any (m > amax))
error ("bitcmp: K must be in the range [1,%d]", amax);
endif
mask = bitshift (bmax, k - amax);
C = bitxor (bitand (A, mask), mask);
endif
endfunction
%!test
%! Amax = 53;
%! Bmax = flintmax - 1;
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),bitor (bitshift (1,Amax-1), bitshift (1,Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (1,Amax-2));
%! assert (bitcmp (A,Amax-2), 0);
%!test
%! Amax = 24;
%! Bmax = flintmax ("single") - 1;
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),
%! bitor (bitshift (single (1),Amax-1), bitshift (single (1),Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (single (1),Amax-2));
%! assert (bitcmp (A,Amax-2), single (0));
%!test
%! Amax = 8;
%! Bmax = intmax ("uint8");
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),
%! bitor (bitshift (uint8 (1),Amax-1), bitshift (uint8 (1),Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (uint8 (1),Amax-2));
%! assert (bitcmp (A,Amax-2), uint8 (0));
%!test
%! Amax = 16;
%! Bmax = intmax ("uint16");
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),
%! bitor (bitshift (uint16 (1),Amax-1), bitshift (uint16 (1),Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (uint16 (1),Amax-2));
%! assert (bitcmp (A,Amax-2), uint16 (0));
%!test
%! Amax = 32;
%! Bmax = intmax ("uint32");
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),
%! bitor (bitshift (uint32 (1),Amax-1), bitshift (uint32 (1),Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (uint32 (1),Amax-2));
%! assert (bitcmp (A,Amax-2), uint32 (0));
%!test
%! Amax = 64;
%! Bmax = intmax ("uint64");
%! A = bitshift (Bmax,-2);
%! assert (bitcmp (A,Amax),
%! bitor (bitshift (uint64 (1),Amax-1), bitshift (uint64 (1),Amax-2)));
%! assert (bitcmp (A,Amax-1), bitshift (uint64 (1),Amax-2));
%! assert (bitcmp (A,Amax-2), uint64 (0));
## Do not forget signed integers
%!assert (bitcmp (int8 (127)), int8 (-128)) # [1 1 1 1 1 1 1 0]
%!assert (bitcmp (int8 (1)), int8 (-2)) # [1 0 0 0 0 0 0 0]
%!assert (bitcmp (int8 (0)), int8 (-1)) # [0 0 0 0 0 0 0 0]
%!assert (bitcmp (int8 (8)), int8 (-9)) # [0 0 0 1 0 0 0 0]
|
