GNU Radio 3.6.0 C++ API
gr_correlate_access_code_tag_bb.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2005,2006,2011 Free Software Foundation, Inc.
00004  *
00005  * This file is part of GNU Radio
00006  *
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  *
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_gr_correlate_access_code_tag_bb_H
00024 #define INCLUDED_gr_correlate_access_code_tag_bb_H
00025 
00026 #include <gr_core_api.h>
00027 #include <gr_sync_block.h>
00028 #include <string>
00029 
00030 class gr_correlate_access_code_tag_bb;
00031 typedef boost::shared_ptr<gr_correlate_access_code_tag_bb> gr_correlate_access_code_tag_bb_sptr;
00032 
00033 /*!
00034  * \param access_code is represented with 1 byte per bit, e.g., "010101010111000100"
00035  * \param threshold maximum number of bits that may be wrong
00036  * \param tag_name key of the tag inserted into the tag stream
00037  */
00038 GR_CORE_API gr_correlate_access_code_tag_bb_sptr
00039 gr_make_correlate_access_code_tag_bb (const std::string &access_code, int threshold,
00040                                       const std::string &tag_name);
00041 
00042 /*!
00043  * \brief Examine input for specified access code, one bit at a time.
00044  * \ingroup sync_blk
00045  *
00046  * input:  stream of bits, 1 bit per input byte (data in LSB)
00047  * output: unaltered stream of bits (plus tags)
00048  *
00049  * This block annotates the input stream with tags. The tags have key
00050  * name [tag_name], specified in the constructor. Used for searching
00051  * an input data stream for preambles, etc.
00052  */
00053 class GR_CORE_API gr_correlate_access_code_tag_bb : public gr_sync_block
00054 {
00055   friend GR_CORE_API gr_correlate_access_code_tag_bb_sptr
00056   gr_make_correlate_access_code_tag_bb (const std::string &access_code, int threshold,
00057                                         const std::string &tag_name);
00058  private:
00059   unsigned long long d_access_code;     // access code to locate start of packet
00060                                         //   access code is left justified in the word
00061   unsigned long long d_data_reg;        // used to look for access_code
00062   unsigned long long d_mask;            // masks access_code bits (top N bits are set where
00063                                         //   N is the number of bits in the access code)
00064   unsigned int       d_threshold;       // how many bits may be wrong in sync vector
00065   unsigned int       d_len;         //the length of the access code
00066 
00067   pmt::pmt_t d_key, d_me; //d_key is the tag name, d_me is the block name + unique ID
00068 
00069  protected:
00070   gr_correlate_access_code_tag_bb(const std::string &access_code, int threshold,
00071                                   const std::string &tag_name);
00072 
00073  public:
00074   ~gr_correlate_access_code_tag_bb();
00075 
00076   int work(int noutput_items,
00077            gr_vector_const_void_star &input_items,
00078            gr_vector_void_star &output_items);
00079 
00080 
00081   /*!
00082    * \param access_code is represented with 1 byte per bit, e.g., "010101010111000100"
00083    */
00084   bool set_access_code (const std::string &access_code);
00085 };
00086 
00087 #endif /* INCLUDED_gr_correlate_access_code_tag_bb_H */