/* -*- c++ -*- */ /* * Copyright 2008,2010,2012 Free Software Foundation, Inc. * * This file is part of GNU Radio * * GNU Radio 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, or (at your option) * any later version. * * GNU Radio 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 GNU Radio; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, * Boston, MA 02110-1301, USA. */ #ifndef INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H #define INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H #include <gnuradio/digital/api.h> #include <gnuradio/sync_block.h> namespace gr { namespace digital { /*! * \ingroup coding_blk * * \brief * Scramble an input stream using an LFSR. * * \details * This block scrambles up to 8 bits per byte of the input * data stream, starting at the LSB. * * The scrambler works by XORing the incoming bit stream by the * output of the LFSR. Optionally, after \p count bits have been * processed, the shift register is reset to the \p seed value. * This allows processing fixed length vectors of samples. * * Alternatively, the LFSR can be reset using a reset tag to * scramble variable length vectors. However, it cannot be reset * between bytes. * * For details on configuring the LFSR, see gr::digital::lfsr. */ class DIGITAL_API additive_scrambler_bb : virtual public sync_block { public: // gr::digital::additive_scrambler_bb::sptr typedef boost::shared_ptr<additive_scrambler_bb> sptr; /*! * \brief Create additive scrambler. * * \param mask Polynomial mask for LFSR * \param seed Initial shift register contents * \param len Shift register length * \param count Number of bytes after which shift register is reset, 0=never * \param bits_per_byte Number of bits per byte * \param reset_tag_key When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!) */ static sptr make(int mask, int seed, int len, int count=0, int bits_per_byte=1, const std::string &reset_tag_key=""); virtual int mask() const = 0; virtual int seed() const = 0; virtual int len() const = 0; virtual int count() const = 0; virtual int bits_per_byte() = 0; }; } /* namespace digital */ } /* namespace gr */ #endif /* INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H */