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/* -*- c++ -*- */
/*
* Copyright 2007,2012 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_IMPL_GLFSR_H
#define INCLUDED_DIGITAL_IMPL_GLFSR_H
#include <digital_api.h>
/*!
* \brief Galois Linear Feedback Shift Register using specified polynomial mask
* \ingroup misc
*
* Generates a maximal length pseudo-random sequence of length 2^degree-1
*/
class DIGITAL_API digital_impl_glfsr
{
private:
int d_shift_register;
int d_mask;
public:
digital_impl_glfsr(int mask, int seed) { d_shift_register = seed; d_mask = mask; }
static int glfsr_mask(int degree);
unsigned char next_bit() {
unsigned char bit = d_shift_register & 1;
d_shift_register >>= 1;
if (bit)
d_shift_register ^= d_mask;
return bit;
}
int mask() const { return d_mask; }
};
#endif /* INCLUDED_DIGITAL_IMPL_GLFSR_H */
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