/* -*- c++ -*- */

/*

 * Copyright 2002,2011,2012 Free Software Foundation, Inc.

 *

 * This file is part of GNU Radio

 *

 * GNU Radio is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3, or (at your option)

 * any later version.

 *

 * GNU Radio is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with GNU Radio; see the file COPYING.  If not, write to

 * the Free Software Foundation, Inc., 51 Franklin Street,

 * Boston, MA 02110-1301, USA.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <cmath>

#include <fft/goertzel.h>

namespace gr {

  namespace fft {

    goertzel::goertzel(int rate, int len, float freq)

    {

      set_params(rate, len, freq);

    }

    void

    goertzel::set_params(int rate, int len, float freq)

    {

      d_d1 = 0.0;

      d_d2 = 0.0;

      float w = 2.0*M_PI*freq/rate;

      d_wr = 2.0*std::cos(w);

      d_wi = std::sin(w);

      d_len = len;

      d_processed = 0;

    }

    gr_complex

    goertzel::batch(float *in)

    {

      d_d1 = 0.0;

      d_d2 = 0.0;

      for(int i = 0; i < d_len; i++)

        input(in[i]);

      return output();

    }

    void

    goertzel::input(const float &input)

    {

      float y = input + d_wr*d_d1 - d_d2;

      d_d2 = d_d1;

      d_d1 = y;

      d_processed++;

    }

    gr_complex

    goertzel::output()

    {

      gr_complex out((0.5*d_wr*d_d1-d_d2)/d_len, (d_wi*d_d1)/d_len);

      d_d1 = 0.0;

      d_d2 = 0.0;

      d_processed = 0;

      return out;

    }

  } /* namespace fft */

}/* namespace gr */