annotate scripts/general/bitset.m @ 5307:4c8a2e4e0717

[project @ 2005-04-26 19:24:27 by jwe]
author jwe
date Tue, 26 Apr 2005 19:24:47 +0000
parents c08cb1098afc
children 2618a0750ae6
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1 ## Copyright (C) 2004 David BAteman
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2 ##
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3 ## This program is free software; you can redistribute it and/or modify
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4 ## it under the terms of the GNU General Public License as published by
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5 ## the Free Software Foundation; either version 2 of the License, or
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6 ## (at your option) any later version.
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7 ##
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8 ## This program is distributed in the hope that it will be useful,
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9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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11 ## GNU General Public License for more details.
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12 ##
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13 ## You should have received a copy of the GNU General Public License
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14 ## along with this program; if not, write to the Free Software
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15 ## Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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16 ## 02110-1301 USA
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17
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18 ## -*- texinfo -*-
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19 ## @deftypefn {Function File} {@var{x} =} bitset (@var{a}, @var{n})
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20 ## @deftypefnx {Function File} {@var{x} =} bitset (@var{a}, @var{n}, @var{v})
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21 ## Set or reset bit(s) @var{n} of unsigned integers in @var{a}.
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22 ## @var{v} = 0 resets and @var{v} = 1 sets the bits.
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23 ## The lowest significant bit is: @var{n} = 1
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24 ##
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25 ## @example
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26 ## dec2bin (bitset (10, 1))
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27 ## @result{} 1011
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28 ## @end example
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29 ## @end deftypefn
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30 ##
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31 ## @seealso{bitand, bitor, bitxor, bitget, bitcmp, bitshift, bitmax}
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32
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33 ## Liberally based of the version by Kai Habel from octave-forge
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34
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35 function X = bitset (A, n, value)
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36
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37 if (nargin < 2 || nargin > 3)
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38 usage ("bitset (A, n, v)");
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39 endif
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40
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41 if (nargin == 2)
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42 value = 1;
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43 endif
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44
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45 if (isa (A, "double"))
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46 Bmax = bitmax;
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47 Amax = log2 (Bmax) + 1;
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48 _conv = @double;
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49 else
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50 if (isa (A, "uint8"))
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51 Amax = 8;
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52 _conv = @uint8;
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53 elseif (isa (A, "uint16"))
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54 Amax = 16;
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55 _conv = @uint16;
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56 elseif (isa (A, "uint32"))
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57 Amax = 32;
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58 _conv = @uint32;
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59 elseif (isa (A, "uint64"))
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60 Amax = 64;
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61 _conv = @uint64;
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62 elseif (isa (A, "int8"))
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63 Amax = 8;
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64 _conv = @int8;
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65 elseif (isa (A, "int16"))
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66 Amax = 16;
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67 _conv = @int16;
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68 elseif (isa (A, "int32"))
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69 Amax = 32;
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70 _conv = @int32;
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71 elseif (isa (A, "int64"))
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72 Amax = 64;
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73 _conv = @int64;
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74 else
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75 error ("invalid class %s", class (A));
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76 endif
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77 Bmax = intmax (class (A));
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78 endif
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79
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80 m = double (n(:));
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81 if (any (m < 1) || any (m > Amax))
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82 error ("n must be in the range [1,%d]", Amax);
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83 endif
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84
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85 mask = bitshift (_conv (1), uint8 (n) - uint8 (1));
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86 X = bitxor (A, bitand (A, mask));
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87
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88 if (value)
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89 X = bitor (A, mask);
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90 endif
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91
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92 endfunction