Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / communications-1.1.1 / de2bi.m

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+## Copyright (C) 2001 Laurent Mazet
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{b} = } de2bi (@var{d})
+## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n})
+## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n},@var{p})
+## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n},@var{p},@var{f})
+##
+## Convert a non-negative integer to bit vector.
+##
+## The variable @var{d} must be a vector of non-negative integers. @dfn{de2bi}
+## then returns a matrix where each row represents the binary representation
+## of elements of @var{d}. If @var{n} is defined then the returned matrix
+## will have @var{n} columns. This number of columns can be either larger
+## than the minimum needed and zeros will be added to the msb of the
+## binary representation or smaller than the minimum in which case the
+## least-significant part of the element is returned.
+##
+## If @var{p} is defined then it is used as the base for the decomposition
+## of the returned values. That is the elements of the returned value are
+## between '0' and 'p-1'.
+##
+## The variable @var{f} defines whether the first or last element of @var{b}
+## is considered to be the most-significant. Valid values of @var{f} are
+## 'right-msb' or 'left-msb'. By default @var{f} is 'right-msb'.
+##
+## @seealso{bi2de}
+## @end deftypefn
+
+function b = de2bi (d, n, p, f)
+
+  if (nargin == 1)
+    p = 2;
+    n = floor ( log (max (max (d), 1)) ./ log (p) ) + 1;
+    f = 'right-msb';
+  elseif (nargin == 2)
+    p = 2;
+    f = 'right-msb';
+  elseif (nargin == 3)
+    if (ischar (p))
+      f = p;
+      p = 2;
+    else
+      f = 'right-msb';
+    endif
+  elseif (nargin == 4)
+    if (ischar (p))
+      tmp = f;
+      f = p;
+      p = tmp;
+    endif
+  else
+    print_usage ();
+  endif
+
+  d = d(:);
+  if ( any (d < 0) || any (d != floor (d)) )
+    error ("de2bi: d must only contain non-negative integers");
+  endif
+
+  if (isempty (n))
+    n = floor ( log (max (max (d), 1)) ./ log (p) ) + 1;
+  endif
+
+  power = ones (length (d), 1) * (p .^ [0 : n-1] );
+  d = d * ones (1, n);
+  b = floor (rem (d, p*power) ./ power);
+
+  if (strcmp (f, 'left-msb'))
+    b = b(:,columns(b):-1:1);
+  elseif (!strcmp (f, 'right-msb'))
+    error ("de2bi: unrecognized flag");
+  endif
+
+endfunction
+
+                                %!shared x
+                                %! x = randi ([0 2^16-1], 100, 1);
+                                %!assert (de2bi (0), 0)
+                                %!assert (de2bi (1), 1)
+                                %!assert (de2bi (255), ones (1, 8))
+                                %!assert (de2bi (255, [], 256), 255)
+                                %!assert (de2bi (1023, 8, 8), [7 7 7 1 0 0 0 0])
+                                %!assert (size (de2bi (x, 16)), [100 16])
+                                %!assert (de2bi (x, 16, "right-msb"), de2bi (x, 16))
+                                %!assert (de2bi (x, 16, "left-msb"), fliplr (de2bi (x, 16)))
+
+%% Test input validation
+                                %!error de2bi ()
+                                %!error de2bi (1, 2, 3, 4, 5)
+                                %!error de2bi (1, 2, 3, 4)
+                                %!error de2bi (1, 2, 3, "invalid")
+                                %!error de2bi (0.1)
+                                %!error de2bi (-1)