#include "soundfile.h"

int main(int argc, char** argv) {
   Options options;
   options.process(argc, argv);

   SoundFileRead  insound(options.getArg(1));
   SoundHeader    header = insound;
   header.setChannels(1);          // write only mono file
   SoundFileWrite outsound(options.getArg(2), header);

   int sampleCount = insound.getSamples();
   double a          = 0.9;        // the feedback gain          a
   double insample   = 0.0;        // the current input sample   x[n]
   double insample2  = 0.0;        // the last input sample      x[n-1]
   double outsample  = 0.0;        // the current output sample  y[n]
   double outsample2 = 0.0;        // the last output sample     y[n-1]
   int i;

   // implementing the difference equation: y[n] = x[n] - x[n-1] + a * y[n-1]
   for (i=0; i<sampleCount; i++) {
      insound.incrementSample();
      outsample2 = outsample;
      insample2  = insample;
      insample   = insound.getCurrentSampleDouble(0);
      outsample  = insample - insample2 + a * outsample2;
      outsound.writeSampleDouble(outsample);
   }

   return 0;
}