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

/*

 * Copyright 2005,2010 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 <gr_simple_squelch_cc.h>

#include <gr_io_signature.h>

#include <cmath>

gr_simple_squelch_cc_sptr

gr_make_simple_squelch_cc(double threshold_db, double alpha)

{

  return gnuradio::get_initial_sptr(new gr_simple_squelch_cc(threshold_db, alpha));

}

gr_simple_squelch_cc::gr_simple_squelch_cc (double threshold_db, double alpha)

  : gr_sync_block ("simple_squelch_cc",

                   gr_make_io_signature(1, 1, sizeof(gr_complex)),

                   gr_make_io_signature(1, 1, sizeof(gr_complex))),

    d_iir(alpha), d_unmuted(false)

{

  set_threshold (threshold_db);

}

gr_simple_squelch_cc::~gr_simple_squelch_cc()

{

}

int

gr_simple_squelch_cc::work(int noutput_items,

                           gr_vector_const_void_star &input_items,

                           gr_vector_void_star &output_items)

{

  const gr_complex *in = (const gr_complex *) input_items[0];

  gr_complex *out = (gr_complex *) output_items[0];

  for (int i = 0; i < noutput_items; i++){

    double mag_sqrd = in[i].real()*in[i].real() + in[i].imag()*in[i].imag();

    double f = d_iir.filter(mag_sqrd);

    if (f >= d_threshold)

      out[i] = in[i];

    else

      out[i] = 0;

  }

  d_unmuted = d_iir.prev_output() >= d_threshold;

  return noutput_items;

}

void

gr_simple_squelch_cc::set_threshold(double decibels)

{

  // convert to absolute threshold (mag squared)

  d_threshold = std::pow(10.0, decibels/10);

}

double

gr_simple_squelch_cc::threshold() const

{

  return 10 * log10(d_threshold);

}

void

gr_simple_squelch_cc::set_alpha(double alpha)

{

  d_iir.set_taps(alpha);

}

std::vector<float>

gr_simple_squelch_cc::squelch_range() const

{

  std::vector<float> r(3);

  r[0] = -50.0;                                // min        FIXME

  r[1] = +50.0;                                // max        FIXME

  r[2] = (r[1] - r[0]) / 100;                // step size

  return r;

}