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1 ## Copyright (C) 2004, 2005, 2006, 2007 David Bateman |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {} bitcmp (@var{a}, @var{k}) |
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21 ## Return the @var{k}-bit complement of integers in @var{a}. If |
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22 ## @var{k} is omitted @code{k = log2 (bitmax) + 1} is assumed. |
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23 ## |
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24 ## @example |
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25 ## bitcmp(7,4) |
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26 ## @result{} 8 |
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27 ## dec2bin(11) |
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28 ## @result{} 1011 |
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29 ## dec2bin(bitcmp(11, 6)) |
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30 ## @result{} 110100 |
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31 ## @end example |
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32 ## @seealso{bitand, bitor, bitxor, bitset, bitget, bitcmp, bitshift, bitmax} |
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33 ## @end deftypefn |
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34 |
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35 ## Liberally based of the version by Kai Habel from octave-forge |
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36 |
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37 function x = bitcmp (a, n) |
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38 |
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39 if (nargin < 1 || nargin > 2) |
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40 print_usage (); |
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41 endif |
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42 |
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43 if (nargin == 2 && (! isscalar (n) || (floor (n) != n))) |
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44 error("k must be a scalar integer") |
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45 endif |
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46 |
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47 if (isa (a, "double")) |
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48 bmax = bitmax; |
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49 amax = ceil (log2 (bmax)); |
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50 else |
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51 if (isa (a, "uint8")) |
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52 amax = 8; |
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53 elseif (isa (a, "uint16")) |
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54 amax = 16; |
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55 elseif (isa (a, "uint32")) |
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56 amax = 32; |
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57 elseif (isa (a, "uint64")) |
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58 amax = 64; |
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59 elseif (isa (a, "int8")) |
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60 amax = 8; |
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61 elseif (isa (a, "int16")) |
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62 amax = 16; |
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63 elseif (isa (a, "int32")) |
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64 amax = 32; |
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65 elseif (isa (a, "int64")) |
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66 amax = 64; |
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67 else |
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68 error ("invalid class %s", class (a)); |
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69 endif |
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70 bmax = intmax (class (a)); |
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71 endif |
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72 |
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73 if (nargin == 1 || n == amax) |
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74 x = bitxor (a, bmax); |
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75 else |
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76 m = double (n); |
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77 if (any (m < 1) || any (m > amax)) |
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78 error ("n must be in the range [1,%d]", amax); |
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79 endif |
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80 mask = bitshift (bmax, n - amax); |
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81 x = bitxor (bitand (a, mask), mask); |
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82 endif |
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83 endfunction |
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84 |
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85 %!shared Amax,Bmax,A |
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86 %! Amax=53; |
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87 %! Bmax = bitmax; |
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88 %! A = bitshift(Bmax,-2); |
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89 %!assert(bitcmp(A,Amax),bitor(bitshift(1,Amax-1),bitshift(1,Amax-2))); |
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90 %!assert(bitcmp(A,Amax-1),bitshift(1,Amax-2)); |
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91 %!assert(bitcmp(A,Amax-2),0); |
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92 %!shared Amax,Bmax,A |
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93 %! Amax=8; |
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94 %! Bmax = intmax('uint8'); |
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95 %! A = bitshift(Bmax,-2); |
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96 %!assert(bitcmp(A,Amax),bitor(bitshift(uint8(1),Amax-1),bitshift(uint8(1),Amax-2))); |
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97 %!assert(bitcmp(A,Amax-1),bitshift(uint8(1),Amax-2)); |
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98 %!assert(bitcmp(A,Amax-2),uint8(0)); |
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99 %!shared Amax,Bmax,A |
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100 %! Amax=16; |
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101 %! Bmax = intmax('uint16'); |
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102 %! A = bitshift(Bmax,-2); |
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103 %!assert(bitcmp(A,Amax),bitor(bitshift(uint16(1),Amax-1),bitshift(uint16(1),Amax-2))); |
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104 %!assert(bitcmp(A,Amax-1),bitshift(uint16(1),Amax-2)); |
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105 %!assert(bitcmp(A,Amax-2),uint16(0)); |
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106 %!shared Amax,Bmax,A |
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107 %! Amax=32; |
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108 %! Bmax = intmax('uint32'); |
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109 %! A = bitshift(Bmax,-2); |
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110 %!assert(bitcmp(A,Amax),bitor(bitshift(uint32(1),Amax-1),bitshift(uint32(1),Amax-2))); |
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111 %!assert(bitcmp(A,Amax-1),bitshift(uint32(1),Amax-2)); |
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112 %!assert(bitcmp(A,Amax-2),uint32(0)); |
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113 %!shared Amax,Bmax,A |
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114 %! Amax=64; |
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115 %! Bmax = intmax('uint64'); |
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116 %! A = bitshift(Bmax,-2); |
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117 %!assert(bitcmp(A,Amax),bitor(bitshift(uint64(1),Amax-1),bitshift(uint64(1),Amax-2))); |
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118 %!assert(bitcmp(A,Amax-1),bitshift(uint64(1),Amax-2)); |
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119 %!assert(bitcmp(A,Amax-2),uint64(0)); |
