Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/communications-1.1.1/fibodeco.m b/octave_packages/communications-1.1.1/fibodeco.m
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+## Copyright (C) 2006 Muthiah Annamalai <muthiah.annamalai@uta.edu>
+##
+## 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} { } fibodeco (@var{code})
+## 
+## Returns the decoded fibonacci value from the binary vectors @var{code}.
+## Universal codes like fibonacci codes Have a useful synchronization property,
+## only for 255 maximum value we have designed these routines. We assume
+## user has partitioned the code into several unique segments based on
+## the suffix property of unique strings "11" and we just decode the
+## parts. Partitioning the stream is as simple as identifying the
+## "11" pairs that occur, at the terminating ends. This system implements
+## the standard binaary Fibonacci codes, which means that row vectors
+## can only contain 0 or 1. Ref: @url{http://en.wikipedia.org/wiki/Fibonacci_coding}
+## 
+## @example
+## @group
+##     fibodeco(@{[0 1 0 0 1 1]@}) %decoded to 10
+##     fibodeco(@{[1 1],[0 1 1],[0 0 1 1],[1 0 1 1]@}) %[1:4]
+## @end group
+## @end example
+## @end deftypefn
+## @seealso{fiboenco}
+  
+function num=fibodeco(code)
+  ##
+  ## generate fibonacci series table.
+  ##
+  ## f(1)=1;
+  ## f(2)=1;
+  ##
+  ## while ((f(end-1)+f(end)) < 256)
+  ##    val=(f(end-1)+f(end));
+  ##    f=[f val];
+  ## end
+  ## f=f(2:end);
+  ##
+  ##all numbers terminate with 1 except 0 itself.
+  ##
+  ##
+  ##f= [75025   46368   28657   17711   10946    6765    4181    2584 \
+  ##    1597     987    610     377     233     144      89      55 \
+  ##    34      21      13   8       5       3       2       1];
+  ##
+  ##f= [ 233   144    89    55    34    21    13     8     5     3  2     1];
+
+  f= [  1     2     3     5     8    13    21    34    55    89   144   233];     
+  L_C=length(code);
+
+  if (nargin < 1)
+    error("Usage:fibodec(cell-array vectors), where each vector is +ve sequence of numbers ...
+             either 1 or 0");
+  end
+
+  for j=1:L_C
+    word=code{j};
+    ##discard the terminating 1.
+    word=word(1:end-1);
+    L=length(word);
+    num(j)=sum(word.*f(1:L));
+  end
+  
+  return
+end
+%!
+%! assert(fibodeco({[1 1],[0 1 1],[0 0 1 1],[1 0 1 1]}),[1:4])
+%! assert(fibodeco({[0 1 0 0 1 1]}),10)
+%!