/* -*- c++ -*- */
/*
 * Copyright 2004 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_wvps_ff.h>
#include <gr_io_signature.h>
#include <string.h>

static int
ceil_log2(int k)
{
  int m = 0;
  for (int n = k-1; n > 0; n >>= 1) m++;
  return m;
}

gr_wvps_ff_sptr
gr_make_wvps_ff(int ilen)
{
  return gr_wvps_ff_sptr(new gr_wvps_ff(ilen));
}

gr_wvps_ff::gr_wvps_ff(int ilen)
  : gr_sync_block("wvps_ff",
		  gr_make_io_signature(1, 1, sizeof(float) * ilen),
		  gr_make_io_signature(1, 1, sizeof(float) * ceil_log2(ilen))),
    d_ilen(ilen), d_olen(ceil_log2(ilen))
{
}

// input vector assumed to be output from gsl wavelet computation

int
gr_wvps_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 count = 0; count < noutput_items; count++) {

    // any power?

    if (in[0] == 0.0) {
      for (int i = 0; i < d_olen; i++)
	out[i] = 0.0;

    } else {
      
      // get power normalization from 0-th wavelet coefficient

      float scl = 1.0/(in[0]*in[0]);
      int k = 1;
      
      // sum powers over sequences of bins,
      // sequence lengths in increasing powers of 2
      
      for (int e = 0; e < d_olen; e++) {
	int m = 01<<e;
	float sum = 0.0;
	
	for (int l = 0; l < m; l++)
	  sum += (in[k+l]*in[k+l]);
	
	out[e] = scl*sum;
	k += m;
      }
    }

    in  += d_ilen;
    out += d_olen;
  }

  return noutput_items;
}
