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## Copyright (C) 2004-2013 David Bateman
##
## 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
## <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {} bitcmp (@var{A}, @var{k})
## Return the @var{k}-bit complement of integers in @var{A}. If
## @var{k} is omitted @code{k = log2 (bitmax) + 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, bitmax}
## @end deftypefn
## Liberally based on the version by Kai Habel from octave-forge
function C = bitcmp (A, k)
if (nargin < 1 || nargin > 2)
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 = bitmax;
amax = ceil (log2 (bmax));
elseif (isa (A, "single"))
bmax = bitmax ("single");
amax = ceil (log2 (bmax));
else
if (isa (A, "uint8"))
amax = 8;
elseif (isa (A, "uint16"))
amax = 16;
elseif (isa (A, "uint32"))
amax = 32;
elseif (isa (A, "uint64"))
amax = 64;
elseif (isa (A, "int8"))
amax = 8;
elseif (isa (A, "int16"))
amax = 16;
elseif (isa (A, "int32"))
amax = 32;
elseif (isa (A, "int64"))
amax = 64;
else
error ("bitcmp: invalid class %s", class (A));
endif
bmax = intmax (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 = bitmax;
%! 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 = bitmax ("single");
%! 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));
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