/*---------------------------------------------------------------------------*
 *                                   IT++			             *
 *---------------------------------------------------------------------------*
 * Copyright (c) 1995-2004 by Tony Ottosson, Thomas Eriksson, Pål Frenger,   *
 * Tobias Ringström, and Jonas Samuelsson.                                   *
 *                                                                           *
 * Permission to use, copy, modify, and distribute this software and its     *
 * documentation under the terms of the GNU General Public License is hereby *
 * granted. No representations are made about the suitability of this        *
 * software for any purpose. It is provided "as is" without expressed or     *
 * implied warranty. See the GNU General Public License for more details.    *
 *---------------------------------------------------------------------------*/

/*! 
  \file 
  \brief Definition of a BCH encoder/decoder class
  \author Pål Frenger

  1.8

  2004/08/17 09:04:07
*/

#ifndef _bch_h
#define _bch_h

#include "comm/galois.h"

namespace itpp {

  /*!
    \defgroup fec Forward Error Correcting Codes
  */

  //---------------------- BCH --------------------------------------

  /*! 
    \ingroup fec
    \brief Class for binary, narrow-sense BCH codes.
  
    The notation used is found in S. B. Wicker, "Error control systems for
    digital communication and storage", Appendix E, Prentice-Hall, 1995.

    Example: 
    \code BCH bch(31,21,2,"3 5 5 1") 
    \endcode 
    uses the generator polynomial
    \f$g(x) = x^{10} + x^9 + x^8 + x^6 + x^5 + x^3 + 1\f$, and is capable of
    correcting 2 errors with \a n = 31 and \a k = 21.
  */
  class BCH {
  public:
    //! Initialize a (n,k)-code that can correct t errors
    BCH(int in_n, int in_k, int in_t, ivec genpolynom);
    //! Encode a bvec of indata
    void encode(const bvec &uncodedbits, bvec &codedbits);
    //! Encode a bvec of indata
    bvec encode(const bvec &uncodedbits);
    //! Decode a bvec of coded data.
    void decode(const bvec &codedbits, bvec &decodedbits);
    //! Decode a bvec of coded data
    bvec decode(const bvec &codedbits);
    //! Get the code rate
    double get_rate() {return double(k)/double(n); }

    //protected:
  private:
    int n, k, t;
    GFX g;
  };

} //namespace itpp

#endif // _bch_h