/* -*- c++ -*- */
/*
 * Copyright 2005 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 2, 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gr_signal_level_ff.h>
#include <gr_io_signature.h>
#include <cmath>

gr_signal_level_ff_sptr
gr_make_signal_level_ff(double threshold_db, double alpha)
{
  return gr_signal_level_ff_sptr(new gr_signal_level_ff(threshold_db, alpha));
}

gr_signal_level_ff::gr_signal_level_ff (double threshold_db, double alpha)
  : gr_sync_block ("signal_level_ff",
		   gr_make_io_signature(1, 1, sizeof(float)),
		   gr_make_io_signature(1, 1, sizeof(float))),
    d_iir(alpha), d_unmuted(false), d_level(0)
{
  set_threshold (threshold_db);
}

gr_signal_level_ff::~gr_signal_level_ff()
{
}


int
gr_signal_level_ff::work(int noutput_items,
			   gr_vector_const_void_star &input_items,
			   gr_vector_void_star &output_items)
{
  const float *in = (const float *) input_items[0];
  float *out = (float *) output_items[0];

  for (int i = 0; i < noutput_items; i++){
    double mag_sqrd = in[i]*in[i];
    double f = d_iir.filter(mag_sqrd);
    out[i] = in[i];
  }

  d_unmuted = d_iir.prev_output() >= d_threshold;
  d_level = d_iir.prev_output();
  return noutput_items;
}

void
gr_signal_level_ff::set_threshold(double decibels)
{
  // convert to absolute threshold (mag squared)
  d_threshold = std::pow(10.0, decibels/10);
}

void
gr_signal_level_ff::set_alpha(double alpha)
{
  d_iir.set_taps(alpha);
}