GNU Radio 3.5.1 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 <gr_core_api.h>
00027 #include <gri_lfsr_15_1_0.h>
00028 
00029 /*!
00030  * \brief generate pseudo-random sequence of length 32768 bits.
00031  * \ingroup misc
00032  *
00033  * This is based on gri_lfsr_15_1_0 with an extra 0 added at the end
00034  * of the sequence.
00035  */
00036 
00037 class GR_CORE_API gri_lfsr_32k {
00038   gri_lfsr_15_1_0       d_lfsr;
00039   unsigned int          d_count;
00040 
00041  public:
00042   gri_lfsr_32k () { reset (); }
00043 
00044   void reset (){
00045     d_lfsr.reset ();
00046     d_count = 0;
00047   }
00048     
00049   int next_bit (){
00050     if (d_count == 32767){
00051       d_count = 0;
00052       return 0;
00053     }
00054     d_count++;
00055     return d_lfsr.next_bit ();
00056   }
00057 
00058   int next_byte (){
00059     int v = 0;
00060     for (int i = 0; i < 8; i++){
00061       v >>= 1;
00062       if (next_bit ())
00063         v |= 0x80;
00064     }
00065     return v;
00066   }
00067 
00068   int next_short (){
00069     int v = 0;
00070     for (int i = 0; i < 16; i++){
00071       v >>= 1;
00072       if (next_bit ())
00073         v |= 0x8000;
00074     }
00075     return v;
00076   }
00077 
00078 };
00079 
00080 #endif /* INCLUDED_GRI_LFSR_32k_H */