00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2007 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_GLFSR_H 00024 #define INCLUDED_GRI_GLFSR_H 00025 00032 class gri_glfsr 00033 { 00034 private: 00035 int d_shift_register; 00036 int d_mask; 00037 00038 public: 00039 00040 gri_glfsr(int mask, int seed) { d_shift_register = seed; d_mask = mask; } 00041 static int glfsr_mask(int degree); 00042 00043 unsigned char next_bit() { 00044 unsigned char bit = d_shift_register & 1; 00045 d_shift_register >>= 1; 00046 if (bit) 00047 d_shift_register ^= d_mask; 00048 return bit; 00049 } 00050 00051 int mask() const { return d_mask; } 00052 }; 00053 00054 #endif /* INCLUDED_GRI_GLFSR_H */