/*!
 * \file
 * \brief Definitions of a Hamming code class
 * \author Tony Ottosson
 *
 * -------------------------------------------------------------------------
 *
 * IT++ - C++ library of mathematical, signal processing, speech processing,
 *        and communications classes and functions
 *
 * Copyright (C) 1995-2009  (see AUTHORS file for a list of contributors)
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * -------------------------------------------------------------------------
 */

#ifndef HAMMING_H
#define HAMMING_H

#include <itpp/base/vec.h>
#include <itpp/base/mat.h>
#include <itpp/comm/channel_code.h>


namespace itpp
{

/*!
  \ingroup fec
  \brief Binary Hamming codes
*/
class Hamming_Code : public Channel_Code
{
public:
  //! Constructor for \c hamming(n,k). n = pow(2,m)-1 and k = pow(2,m)-m-1.
  Hamming_Code(short m);

  //! Destructor
  virtual ~Hamming_Code() { }

  //! Hamming encoder. Will truncate some bits if not \a length = \c integer * \a k.
  virtual void encode(const bvec &uncoded_bits, bvec &coded_bits);
  //! Hamming encoder. Will truncate some bits if not \a length = \c integer * \a k.
  virtual bvec encode(const bvec &uncoded_bits);

  //! Hamming decoder. Will truncate some bits if not \a length = \c integer * \a n.
  virtual void decode(const bvec &coded_bits, bvec &decoded_bits);
  //! Hamming decoder. Will truncate some bits if not \a length = \c integer * \a n.
  virtual bvec decode(const bvec &coded_bits);

  // Soft-decision decoding is not implemented
  virtual void decode(const vec &received_signal, bvec &output);
  virtual bvec decode(const vec &received_signal);

  //! Get the code rate
  virtual double get_rate() const { return static_cast<double>(k) / n; };

  //! Gets the code length \a n.
  short get_n() const { return n; };
  //! Gets the number of information bits per code word, \a k.
  short get_k() const { return k; };
  //! Gets the parity check matrix for the code.
  bmat get_H() const { return H; };
  //! Gets the generator matrix for the code.
  bmat get_G() const { return G; };
private:
  short n, k;
  bmat H, G;
  void generate_H(void);
  void generate_G(void);
};

} // namespace itpp

#endif // #ifndef HAMMING_H
