GNU Radio 3.4.0 C++ API
gri_lfsr_32k.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 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_GRI_LFSR_32k_H
00024 #define INCLUDED_GRI_LFSR_32k_H
00025 
00026 #include <gri_lfsr_15_1_0.h>
00027 
00028 /*!
00029  * \brief generate pseudo-random sequence of length 32768 bits.
00030  * \ingroup misc
00031  *
00032  * This is based on gri_lfsr_15_1_0 with an extra 0 added at the end
00033  * of the sequence.
00034  */
00035 
00036 class gri_lfsr_32k {
00037   gri_lfsr_15_1_0       d_lfsr;
00038   unsigned int          d_count;
00039 
00040  public:
00041   gri_lfsr_32k () { reset (); }
00042 
00043   void reset (){
00044     d_lfsr.reset ();
00045     d_count = 0;
00046   }
00047     
00048   int next_bit (){
00049     if (d_count == 32767){
00050       d_count = 0;
00051       return 0;
00052     }
00053     d_count++;
00054     return d_lfsr.next_bit ();
00055   }
00056 
00057   int next_byte (){
00058     int v = 0;
00059     for (int i = 0; i < 8; i++){
00060       v >>= 1;
00061       if (next_bit ())
00062         v |= 0x80;
00063     }
00064     return v;
00065   }
00066 
00067   int next_short (){
00068     int v = 0;
00069     for (int i = 0; i < 16; i++){
00070       v >>= 1;
00071       if (next_bit ())
00072         v |= 0x8000;
00073     }
00074     return v;
00075   }
00076 
00077 };
00078 
00079 #endif /* INCLUDED_GRI_LFSR_32k_H */