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VrInterpolatingSigProc.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  *  Copyright 1997 Massachusetts Institute of Technology
00024  * 
00025  *  Permission to use, copy, modify, distribute, and sell this software and its
00026  *  documentation for any purpose is hereby granted without fee, provided that
00027  *  the above copyright notice appear in all copies and that both that
00028  *  copyright notice and this permission notice appear in supporting
00029  *  documentation, and that the name of M.I.T. not be used in advertising or
00030  *  publicity pertaining to distribution of the software without specific,
00031  *  written prior permission.  M.I.T. makes no representations about the
00032  *  suitability of this software for any purpose.  It is provided "as is"
00033  *  without express or implied warranty.
00034  * 
00035  */
00036 
00037 #ifndef _VrINTERPOLATINGSIGPROC_H_
00038 #define _VrINTERPOLATINGSIGPROC_H_
00039 
00040 #include <VrHistoryProc.h>
00041 
00042 template<class iType, class oType> 
00043 class VrInterpolatingSigProc : public VrHistoryProc<iType,oType> {
00044 
00045 protected:
00046   int   interp;
00047 
00048 public: 
00049   virtual int forecast(VrSampleRange output,
00050                        VrSampleRange inputs[]);
00051 
00052   virtual void pre_initialize ();
00053 
00054   VrInterpolatingSigProc() : interp(1) {}
00055 
00056   VrInterpolatingSigProc(int outputs) :
00057     VrHistoryProc<iType, oType>(outputs),
00058     interp(1) {}
00059 
00060   VrInterpolatingSigProc(int outputs, int i) :
00061     VrHistoryProc<iType, oType>(outputs),
00062     interp(i) {}
00063 
00064   virtual ~VrInterpolatingSigProc() {}
00065 
00066   virtual int work(VrSampleRange output, void *ao[], VrSampleRange inputs[], void *ai[]);
00067 
00068 };
00069 
00070 template<class iType,class oType> int
00071 VrInterpolatingSigProc<iType,oType>::forecast(VrSampleRange output,
00072                                               VrSampleRange inputs[]) {
00073   /* 1:interp ratio */
00074   /*
00075    * Note that this code only works correctly if output size of the
00076    * module (set using setOutputSize(n) in initialize() ) is a multiple
00077    * of interp.
00078    */
00079   assert ((output.size % interp) == 0);
00080   
00081   for(unsigned int i=0;i<numberInputs;i++) {
00082     inputs[i].index=output.index/interp; /* ! do not subtract history ! */
00083     inputs[i].size=output.size/interp + history-1;
00084   }
00085   return 0;
00086 }  
00087 
00088 
00089 template<class iType,class oType> void 
00090 VrInterpolatingSigProc<iType,oType>::pre_initialize ()
00091 {
00092   assert (interp >= 1);
00093   if (interp == 1){
00094     fprintf (stderr, "### Warning: interp == 1 in pre_initialize of %s.  Are you sure?\n",
00095              name ());
00096   }
00097   if (getSamplingFrequency () == 0.0)
00098     setSamplingFrequency (getInputSamplingFrequencyN (0) * interp);
00099 
00100   setOutputSize(interp);
00101 }
00102 
00103 template<class iType,class oType> int
00104 VrInterpolatingSigProc<iType,oType>::work(VrSampleRange output, void *ao[],
00105                                           VrSampleRange inputs[], void *ai[])
00106 {
00107   iType **i = (iType **)ai;
00108   oType **o = (oType **)ao;
00109   int size = output.size;
00110   iType input_symbol; 
00111 
00112   for (int insamp = 0; insamp < size/interp; insamp++){
00113     input_symbol = i[0][insamp];
00114     *o[0]++ = input_symbol;
00115     for (int outsamp = 1; outsamp < interp; outsamp++){
00116       *o[0]++ = 0;
00117     }
00118   }
00119   return output.size;
00120 }
00121 
00122 #endif

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