FourBitTwo.h

//-*-C++-*-
/***************************************************************************
 *
 *   Copyright (C) 2008 by Willem van Straten
 *   Licensed under the Academic Free License version 2.1
 *
 ***************************************************************************/
 
// dspsr/Kernel/Classes/dsp/FourBitTwo.h
 
#ifndef __FourBitTwo_h
#define __FourBitTwo_h
 
#include "dsp/NLowLookup.h"
 
namespace dsp
{
  class FourBitTwo : public NLowLookup
  {
 
  public:
 
    FourBitTwo (BitTable* table) : NLowLookup (table) { bad = false; }
 
    bool bad;
 
    template<class Iterator>
    inline void prepare (const Iterator& input, unsigned ndat) { }
    
    template<class Iterator>
    inline void unpack (Iterator& input, unsigned ndat, 
                        float* output, unsigned output_incr, unsigned& nlow)
    {
      const unsigned ndat2 = ndat/2;
      nlow = 0;
 
      unsigned total = 0;
 
      for (unsigned idat = 0; idat < ndat2; idat++)
      {
        unsigned index = *input;
        total += index;
 
        ++ input;
 
        *output = lookup[ index*2 ];     output += output_incr;
        *output = lookup[ index*2 + 1 ]; output += output_incr;
        
        nlow += nlow_lookup [index];
      }
 
      bad = (total == 0);
    }
  };
 
}
 
#endif