gr_correlate_access_code_bb.h

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/* -*- c++ -*- */
/*
 * Copyright 2005,2006 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 2, 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifndef INCLUDED_GR_CORRELATE_ACCESS_CODE_BB_H
#define INCLUDED_GR_CORRELATE_ACCESS_CODE_BB_H

#include <gr_sync_block.h>
#include <string>

class gr_correlate_access_code_bb;
typedef boost::shared_ptr<gr_correlate_access_code_bb> gr_correlate_access_code_bb_sptr;

gr_correlate_access_code_bb_sptr 
gr_make_correlate_access_code_bb (const std::string &access_code, int threshold);

class gr_correlate_access_code_bb : public gr_sync_block
{
  friend gr_correlate_access_code_bb_sptr 
  gr_make_correlate_access_code_bb (const std::string &access_code, int threshold);
 private:
  unsigned long long d_access_code;     // access code to locate start of packet
                                        //   access code is left justified in the word
  unsigned long long d_data_reg;        // used to look for access_code
  unsigned long long d_flag_reg;        // keep track of decisions
  unsigned long long d_flag_bit;        // mask containing 1 bit which is location of new flag
  unsigned long long d_mask;            // masks access_code bits (top N bits are set where
                                        //   N is the number of bits in the access code)
  unsigned int       d_threshold;       // how many bits may be wrong in sync vector
  unsigned int       d_flip;            // flip bits if 180 degress out of sync


 protected:
  gr_correlate_access_code_bb(const std::string &access_code, int threshold);

 public:
  ~gr_correlate_access_code_bb();

  int work(int noutput_items,
           gr_vector_const_void_star &input_items,
           gr_vector_void_star &output_items);

  
  bool set_access_code (const std::string &access_code);
};

#endif /* INCLUDED_GR_CORRELATE_ACCESS_CODE_BB_H */

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