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

/*

 * Copyright 2007,2010 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.

 */

// @WARNING@

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <@NAME@.h>

#include <gr_io_signature.h>

#include <string.h>

@SPTR_NAME@

gr_make_@BASE_NAME@ (float threshold_factor_rise,

		     float threshold_factor_fall,

		     int look_ahead, float alpha)

{

  return gnuradio::get_initial_sptr (new @NAME@ (threshold_factor_rise, 

				  threshold_factor_fall,

				  look_ahead, alpha));

}

@NAME@::@NAME@ (float threshold_factor_rise, 

		float threshold_factor_fall,

		int look_ahead, float alpha)

  : gr_sync_block ("@BASE_NAME@",

		   gr_make_io_signature (1, 1, sizeof (@I_TYPE@)),

		   gr_make_io_signature (1, 1, sizeof (char))),

    d_threshold_factor_rise(threshold_factor_rise), 

    d_threshold_factor_fall(threshold_factor_fall),

    d_look_ahead(look_ahead), d_avg_alpha(alpha), d_avg(0), d_found(0)

{

}

int

@NAME@::work (int noutput_items,

	      gr_vector_const_void_star &input_items,

	      gr_vector_void_star &output_items)

{

  @I_TYPE@ *iptr = (@I_TYPE@ *) input_items[0];

  char *optr = (char *) output_items[0];

  memset(optr, 0, noutput_items*sizeof(char));

  @I_TYPE@ peak_val = -(@I_TYPE@)INFINITY;

  int peak_ind = 0;

  unsigned char state = 0;

  int i = 0;

  //printf("noutput_items %d\n",noutput_items);

  while(i < noutput_items) {

    if(state == 0) {  // below threshold

      if(iptr[i] > d_avg*d_threshold_factor_rise) {

	state = 1;

      }

      else {

	d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;

	i++;

      }

    }

    else if(state == 1) {  // above threshold, have not found peak

      //printf("Entered State 1: %f  i: %d  noutput_items: %d\n", iptr[i], i, noutput_items);

      if(iptr[i] > peak_val) {

	peak_val = iptr[i];

	peak_ind = i;

	d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;

	i++;

      }

      else if (iptr[i] > d_avg*d_threshold_factor_fall) {

	d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;

	i++;

      }

      else {

	optr[peak_ind] = 1;

	state = 0;

	peak_val = -(@I_TYPE@)INFINITY;

	//printf("Leaving  State 1: Peak: %f  Peak Ind: %d   i: %d  noutput_items: %d\n", 

	//peak_val, peak_ind, i, noutput_items);

      }

    }

  }

  if(state == 0) {

    //printf("Leave in State 0, produced %d\n",noutput_items);

    return noutput_items;

  }

  else {   // only return up to passing the threshold

    //printf("Leave in State 1, only produced %d of %d\n",peak_ind,noutput_items);

    return peak_ind+1;

  }

}