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annotate scripts/miscellaneous/swapbytes.m @ 7017:a1dbe9d80eee

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[project @ 2007-10-12 21:27:11 by jwe]
author jwe
date Fri, 12 Oct 2007 21:27:37 +0000
parents 93c65f2a5668
children 58604c45ca74
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7017
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1 ## Copyright (C) 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} {} swapbytes (@var{x})
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21 ## Swaps the byte order on values, converting from little endian to big
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22 ## endian and visa-versa. For example
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23 ##
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24 ## @example
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25 ## @group
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26 ## swapbytes (uint16 (1:4))
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27 ## @result{} [ 256 512 768 1024]
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28 ## @end group
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29 ## @end example
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30 ##
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31 ## @seealso{typecast, cast}
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32 ## @end deftypefn
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33
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34 function y = swapbytes (x)
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35 if (nargin != 1)
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36 print_usage ();
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37 endif
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38
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39 clx = class (x);
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40 if (strcmp (clx, "int8") || strcmp (clx, "uint8") || isempty (x))
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41 y = x;
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42 else
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43 if (strcmp (clx, "int16") || strcmp (clx, "uint16"))
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44 nb = 2;
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45 elseif (strcmp (clx, "int32") || strcmp (clx, "uint32"))
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46 nb = 4;
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47 elseif (strcmp (clx, "int64") || strcmp (clx, "uint64") ||
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48 strcmp (clx, "double"))
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49 nb = 8;
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50 else
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51 error ("swapbytes: invalid class of object");
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52 endif
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53 y = reshape (typecast (reshape (typecast (x(:), "uint8"), nb, numel (x))
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54 ([nb : -1 : 1], :) (:), clx), size(x));
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55 endif
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56 endfunction