/*!
 * \file
 * \brief Definitions of a Reed-Solomon codec class
 * \author Pal Frenger, Steve Peters and Adam Piatyszek
 *
 * -------------------------------------------------------------------------
 *
 * 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 REEDSOLOMON_H
#define REEDSOLOMON_H

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


namespace itpp
{

//---------------------- Reed-Solomon --------------------------------------

/*!
  \ingroup fec
  \brief Reed-Solomon Codes.

  Uses the Berlkamp-Massey algorithm for decoding as described in: S. B. Wicker,
  "Error Control Systems for digital communication and storage," Prentice Hall.

  The code is \f$2^m\f$ - ary of length \f$2^m-1\f$ capable of correcting \f$t\f$ errors.
*/
class Reed_Solomon : public Channel_Code
{
public:
  //! Class constructor for the \f$2^m\f$ - ary, \f$t\f$ error correcting RS-code.
  Reed_Solomon(int in_m, int in_t, bool sys = false);
  //! Destructor
  virtual ~Reed_Solomon() { }

  //! Encoder function.
  virtual void encode(const bvec &uncoded_bits, bvec &coded_bits);
  //! Encoder function.
  virtual bvec encode(const bvec &uncoded_bits);

  //! Decoder function
  virtual void decode(const bvec &coded_bits, bvec &decoded_bits);
  //! Decoder function
  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);

  //! Gets the rate of the RS-code.
  virtual double get_rate() const { return static_cast<double>(k) / n; }

  //! Dummy assignment operator - MSVC++ warning C4512
  Reed_Solomon & operator=(const Reed_Solomon &) { return *this; }

protected:
  /*! Internal encoder/decoder parameters
   * @{ */
  int m, t, k, n, q;
  /*! @} */
  //! The generator polynomial of the RS code
  GFX g;
  //! Whether or not the code is systematic
  const bool systematic;
};

} // namespace itpp

#endif // #ifndef REEDSOLOMON_H
