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gr_check_lfsr_32k_s.h

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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2004 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 2, 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., 59 Temple Place - Suite 330,
00020  * Boston, MA 02111-1307, USA.
00021  */
00022 #ifndef INCLUDED_GR_CHECK_LFSR_32K_S_H
00023 #define INCLUDED_GR_CHECK_LFSR_32K_S_H
00024 
00025 #include <gr_sync_block.h>
00026 #include <gri_lfsr_32k.h>
00027 
00028 
00029 class gr_check_lfsr_32k_s;
00030 typedef boost::shared_ptr<gr_check_lfsr_32k_s> gr_check_lfsr_32k_s_sptr;
00031 
00032 gr_check_lfsr_32k_s_sptr gr_make_check_lfsr_32k_s ();
00033 
00041 class gr_check_lfsr_32k_s : public gr_sync_block
00042 {
00043   friend gr_check_lfsr_32k_s_sptr gr_make_check_lfsr_32k_s ();
00044 
00045   enum state {
00046     SEARCHING,          // searching for synchronization
00047     MATCH0,
00048     MATCH1,
00049     MATCH2,
00050     LOCKED              // is locked
00051   };
00052 
00053   state                 d_state;
00054   unsigned int          d_history;              // bitmask of decisions
00055   
00056   long                  d_ntotal;               // total number of shorts
00057   long                  d_nright;               // # of correct shorts
00058   long                  d_runlength;            // # of correct shorts in a row
00059 
00060   static const int BUFSIZE = 2048 - 1;          // ensure pattern isn't packet aligned
00061   int                   d_index;
00062   unsigned short        d_buffer[BUFSIZE];
00063 
00064 
00065   gr_check_lfsr_32k_s ();
00066   
00067   void enter_SEARCHING ();
00068   void enter_MATCH0 ();
00069   void enter_MATCH1 ();
00070   void enter_MATCH2 ();
00071   void enter_LOCKED ();
00072 
00073   void right (){
00074     d_history = (d_history << 1) | 0x1;
00075     d_nright++;
00076     d_runlength++;
00077   }
00078   
00079   void wrong (){
00080     d_history = (d_history << 1) | 0x0;
00081     d_runlength = 0;
00082   }
00083 
00084   bool right_three_times () { return (d_history & 0x7) == 0x7; }
00085   bool wrong_three_times () { return (d_history & 0x7) == 0x0; }
00086 
00087   void log_error (unsigned short expected, unsigned short actual);
00088 
00089  public:
00090 
00091   int work (int noutput_items,
00092             gr_vector_const_void_star &input_items,
00093             gr_vector_void_star &output_items);
00094 
00095   long ntotal () const { return d_ntotal; }
00096   long nright () const { return d_nright; }
00097   long runlength () const { return d_runlength; }
00098 
00099 };
00100 
00101 
00102 #endif /* INCLUDED_GR_CHECK_LFSR_32K_S_H */

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