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scripts/general/bitset.m

changeset 10289: 4b124317dc38
parent:1bf0ce0930be
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (61 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 2004, 2005, 2006, 2007, 2009 David Bateman

     2##

     3## This file is part of Octave.

     4##

     5## Octave is free software; you can redistribute it and/or modify it

     6## under the terms of the GNU General Public License as published by

     7## the Free Software Foundation; either version 3 of the License, or (at

     8## your option) any later version.

     9##

    10## Octave is distributed in the hope that it will be useful, but

    11## WITHOUT ANY WARRANTY; without even the implied warranty of

    12## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13## General Public License for more details.

    14##

    15## You should have received a copy of the GNU General Public License

    16## along with Octave; see the file COPYING.  If not, see

    17## <http://www.gnu.org/licenses/>.

    18

    19## -*- texinfo -*-

    20## @deftypefn {Function File} {@var{x} =} bitset (@var{a}, @var{n})

    21## @deftypefnx {Function File} {@var{x} =} bitset (@var{a}, @var{n}, @var{v})

    22## Set or reset bit(s) @var{n} of unsigned integers in @var{a}.

    23## @var{v} = 0 resets and @var{v} = 1 sets the bits.

    24## The lowest significant bit is: @var{n} = 1

    25##

    26## @example

    27## @group

    28## dec2bin (bitset (10, 1))

    29## @result{} 1011

    30## @end group

    31## @end example

    32## @seealso{bitand, bitor, bitxor, bitget, bitcmp, bitshift, bitmax}

    33## @end deftypefn

    34

    35## Liberally based of the version by Kai Habel from octave-forge

    36

    37function X = bitset (A, n, value)

    38

    39  if (nargin < 2 || nargin > 3)

    40    print_usage ();

    41  endif

    42

    43  if (nargin == 2)

    44    value = 1;

    45  endif

    46  

    47  if (isa (A, "double"))

    48    Bmax = bitmax;

    49    Amax = log2 (Bmax) + 1;

    50    _conv = @double;

    51  else

    52    if (isa (A, "uint8"))

    53      Amax = 8;

    54      _conv = @uint8;

    55    elseif (isa (A, "uint16"))

    56      Amax = 16;

    57      _conv = @uint16;

    58    elseif (isa (A, "uint32"))

    59      Amax = 32;

    60      _conv = @uint32;

    61    elseif (isa (A, "uint64"))

    62      Amax = 64;

    63      _conv = @uint64;

    64    elseif (isa (A, "int8"))

    65      Amax = 8;

    66      _conv = @int8;

    67    elseif (isa (A, "int16"))

    68      Amax = 16;

    69      _conv = @int16;

    70    elseif (isa (A, "int32"))

    71      Amax = 32;

    72      _conv = @int32;

    73    elseif (isa (A, "int64"))

    74      Amax = 64;

    75      _conv = @int64;

    76    else

    77      error ("invalid class %s", class (A));

    78    endif

    79    Bmax = intmax (class (A));

    80  endif

    81

    82  m = double (n(:));

    83  if (any (m < 1) || any (m > Amax))

    84    error ("n must be in the range [1,%d]", Amax);

    85  endif

    86

    87  mask = bitshift (_conv (1), uint8 (n) - uint8 (1));

    88  X = bitxor (A, bitand (A, mask));

    89

    90  if (value)

    91    X = bitor (A, mask);

    92  endif

    93

    94endfunction