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huffmanenco.m

## 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 2 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} {} huffmanenco (@var{sig}, @var{dict})
##
## Returns the Huffman encoded signal using @var{dict}. This function uses 
## a @var{dict} built from the @code{huffmandict} and uses it to encode a
## signal list into a huffman list. A restrictions is that a signal set must
## strictly belong in the range @code{[1,N]} with @code{N = length(dict)}. 
## Also @var{dict} can only be from the @code{huffmandict} routine.
## An exmaple of the use of @code{huffmanenco} is
##
## @example
## @group
##   hd = huffmandict(1:4,[0.5 0.25 0.15 0.10])
##   huffmanenco(1:4,hd) #  [ 1 0 1 0 0 0 0 0 1 ]
## @end group
## @end example
## @end deftypefn
## @seealso{huffmandict, huffmandeco}

function hcode=huffmanenco(sig,dict)
  if ( nargin < 2 || strcmp(class(dict),"cell")~=1 )
    error('usage: huffmanenco(sig,dict)');
  end
  if (max(sig) > length(dict)) || ( min(sig) < 1)
    error("signal has elements that are outside alphabet set ...
      Cannot encode.");
  end
  hcode=[dict{sig}];
  return
end
%! 
%! assert(huffmanenco(1:4, huffmandict(1:4,[0.5 0.25 0.15 0.10])), [ 1   0   1   0   0   0   0   0   1 ],0)
%!

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