## [9770d9]: itpp / comm / reedsolomon.h Maximize Restore History

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 /*! * \file * \brief Definitions of a Reed-Solomon codec class * \author Pal Frenger, Steve Peters and Adam Piatyszek * * ------------------------------------------------------------------------- * * Copyright (C) 1995-2010 (see AUTHORS file for a list of contributors) * * This file is part of IT++ - a C++ library of mathematical, signal * processing, speech processing, and communications classes and functions. * * IT++ 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. * * IT++ 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 IT++. If not, see . * * ------------------------------------------------------------------------- */ #ifndef REEDSOLOMON_H #define REEDSOLOMON_H #include #include #include 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. * The generator polynomial will be $g(x)=\prod_{i=0}^{2t-1}(x-\alpha^{b+i})$, * where $\alpha$ is a root of the primitive polynomial of \c itpp::GF. */ Reed_Solomon(int in_m, int in_t, bool sys = false, int in_b = 1); //! 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); /*! * \brief Decode the RS code bits. Return false if there has been any decoding failure. * * The \c coded_bits are block-wise decoded into \c decoded_message messages. If * there has been any decoding failure, the function will return \c false. * If this happened in the n-th block, then \c cw_isvalid(n) will be set * to \c false (zero-indexed). In case of a systematic code the systematic bits will be * extracted and presented in the corresponding block of \c decoded_message. * This is better than just presenting zeros, which is done in case of a * decoding failure of non-systematic codes. * * For erasure decoding the indices of erased positions need to be passed in \c erasure_positions * as indices to the erased \fsymbol\f (not bit!). * */ virtual bool decode(const bvec &coded_bits, const ivec &erasure_positions, bvec &decoded_message, bvec &cw_isvalid); /*! * \brief Decode the RS code bits. Return false if there has been any decoding failure. * * The \c coded_bits are block-wise decoded into \c decoded_message messages. If * there has been any decoding failure, the function will return \c false. * If this happened in the n-th block, then \c cw_isvalid(n) will be set * to \c false (zero-indexed). In case of a systematic code the systematic bits will be * extracted and presented in the corresponding block of \c decoded_message. * This is better than just presenting zeros, which is done in case of a * decoding failure of non-systematic codes. */ virtual bool decode(const bvec &coded_bits, bvec &decoded_message, bvec &cw_isvalid); //! Decoder a \c bvec of coded data. This function is kept for backward compatibility. Better use \code bool decode(const bvec &coded_bits, bvec &decoded_message, bvec &cw_isvalid)\endcode. virtual void decode(const bvec &coded_bits, bvec &decoded_bits); //! Decoder a \c bvec of coded data. This function is kept for backward compatibility. Better use \code bool decode(const bvec &coded_bits, bvec &decoded_message, bvec &cw_isvalid)\endcode. 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(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, b; /*! @} */ //! 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