/* -*- 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "additive_scrambler_bb_impl.h"
#include <gr_io_signature.h>

namespace gr {
  namespace digital {
    
    additive_scrambler_bb::sptr
    additive_scrambler_bb::make(int mask, int seed, int len, int count)
    {
      return gnuradio::get_initial_sptr(new additive_scrambler_bb_impl
					(mask, seed, len, count));
    }

    additive_scrambler_bb_impl::additive_scrambler_bb_impl(int mask,
							   int seed,
							   int len,
							   int count)
      : gr_sync_block("additive_scrambler_bb",
		      gr_make_io_signature(1, 1, sizeof(unsigned char)),
		      gr_make_io_signature(1, 1, sizeof(unsigned char))),
	d_lfsr(mask, seed, len),
	d_count(count),
	d_bits(0), d_len(len), d_seed(seed)
    {
    }

    additive_scrambler_bb_impl::~additive_scrambler_bb_impl()
    {
    }

    int
    additive_scrambler_bb_impl::mask() const 
    { 
      return d_lfsr.mask();
    }

    int
    additive_scrambler_bb_impl::seed() const
    {
      return d_seed;
    }

    int
    additive_scrambler_bb_impl::len() const
    {
      return d_len;
    }

    int
    additive_scrambler_bb_impl::count() const
    {
      return d_count;
    }

    int
    additive_scrambler_bb_impl::work(int noutput_items,
				     gr_vector_const_void_star &input_items,
				     gr_vector_void_star &output_items)
    {
      const unsigned char *in = (const unsigned char *)input_items[0];
      unsigned char *out = (unsigned char *)output_items[0];

      for(int i = 0; i < noutput_items; i++) {
	out[i] = in[i]^d_lfsr.next_bit();
	if(d_count > 0) {
	  if(++d_bits == d_count) {
	    d_lfsr.reset();
	    d_bits = 0;
	  }
	}
      }

      return noutput_items;
    }

  } /* namespace digital */
} /* namespace gr */