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VrBits2Symbols.h

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00001 /* -*- Mode: c++ -*-  */
00002 /*
00003  * Copyright 2001 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 
00023 #ifndef _VRBITS2SYMBOLS_H_
00024 #define _VRBITS2SYMBOLS_H_
00025 
00026 #include <VrSigProc.h>
00027 
00028 
00029 class VrBits2Symbols : public VrSigProc {
00030 protected:
00031   int valid_bits, output_bits;
00032   u_char current_data;
00033 public:
00034   VrBits2Symbols(int);
00035 
00036   virtual void setOutputBits(int b){
00037     // bug here -> doesn't deal with state properly
00038     output_bits = b;
00039     current_data = 0x0;
00040     valid_bits =0;
00041   };
00042   virtual int work(VrSampleRange output, void *o[], VrSampleRange inputs[], void *i[]);
00043 };
00044 
00045 int VrBits2Symbols::work(VrSampleRange output, void *ao[],
00046                                 VrSampleRange inputs[], void *ai[])
00047 {
00048   char **i = (char **)ai;
00049   char **o = (char **)ao;
00050   int size = output.size, bits_done;
00051   u_char out;
00052 
00053 
00054   while(size-- > 0) {
00055 
00056 
00057     bits_done = 0;
00058     out = 0x00;
00059 
00060     while (bits_done < output_bits){
00061     
00062       if (valid_bits == 0) {
00063       
00064         current_data = *i[0]++;
00065         //      printf("\n %x ", current_data);
00066         valid_bits = 8;
00067       }
00068     
00069       out = (out<<1) + (current_data>>7);  /* msb from current_data becomes lsb of output */
00070       current_data = current_data << 1;
00071       valid_bits--;
00072       bits_done++;    
00073     }
00074 
00075     //printf(" %x ", out);
00076     //if (out > 16) printf("***** Bad result here: size = %d\n", size);
00077     *o[0]++ = out;
00078   }
00079   return output.size;
00080 }
00081 
00082 VrBits2Symbols::VrBits2Symbols(int bits)
00083   : VrSigProc(1, sizeof(char), sizeof(char))
00084 {
00085   output_bits = bits;
00086   valid_bits = 0;
00087 }
00088 
00089 
00090 #endif
00091 
00092 
00093 
00094 
00095 
00096 
00097 

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