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

/*

 * Copyright 2004,2007,2008,2010 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_fft_vcc_fftw.h>

#include <gr_io_signature.h>

#include <gri_fft.h>

#include <math.h>

#include <string.h>

gr_fft_vcc_sptr

gr_make_fft_vcc_fftw (int fft_size, bool forward, const std::vector<float> &window, bool shift)

{

  return gnuradio::get_initial_sptr(new gr_fft_vcc_fftw (fft_size, forward, window, shift));

}

gr_fft_vcc_fftw::gr_fft_vcc_fftw (int fft_size, bool forward,

                                  const std::vector<float> &window, bool shift)

  : gr_fft_vcc("fft_vcc_fftw", fft_size, forward, window, shift)

{

  d_fft = new gri_fft_complex (d_fft_size, forward);

}

gr_fft_vcc_fftw::~gr_fft_vcc_fftw ()

{

  delete d_fft;

}

int

gr_fft_vcc_fftw::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];

  unsigned int input_data_size = input_signature()->sizeof_stream_item (0);

  unsigned int output_data_size = output_signature()->sizeof_stream_item (0);

  int count = 0;

  while (count++ < noutput_items){

    // copy input into optimally aligned buffer

    if (d_window.size()){

      gr_complex *dst = d_fft->get_inbuf();

      if(!d_forward && d_shift){

        unsigned int offset = (!d_forward && d_shift)?(d_fft_size/2):0;

        int fft_m_offset = d_fft_size - offset;

        for (unsigned int i = 0; i < offset; i++)                // apply window

            dst[i+fft_m_offset] = in[i] * d_window[i];

        for (unsigned int i = offset; i < d_fft_size; i++)                // apply window

            dst[i-offset] = in[i] * d_window[i];

      } else {

        for (unsigned int i = 0; i < d_fft_size; i++)                // apply window

          dst[i] = in[i] * d_window[i];

      }

    }

    else {

      if(!d_forward && d_shift) {  // apply an ifft shift on the data

        gr_complex *dst = d_fft->get_inbuf();

        unsigned int len = (unsigned int)(floor(d_fft_size/2.0)); // half length of complex array

        memcpy(&dst[0], &in[len], sizeof(gr_complex)*(d_fft_size - len));

        memcpy(&dst[d_fft_size - len], &in[0], sizeof(gr_complex)*len);

      }

      else {

        memcpy (d_fft->get_inbuf(), in, input_data_size);

      }

    }

    // compute the fft

    d_fft->execute ();

    // copy result to our output

    if(d_forward && d_shift) {  // apply a fft shift on the data

      unsigned int len = (unsigned int)(ceil(d_fft_size/2.0));

      memcpy(&out[0], &d_fft->get_outbuf()[len], sizeof(gr_complex)*(d_fft_size - len));

      memcpy(&out[d_fft_size - len], &d_fft->get_outbuf()[0], sizeof(gr_complex)*len);

    }

    else {

      memcpy (out, d_fft->get_outbuf (), output_data_size);

    }

    in  += d_fft_size;

    out += d_fft_size;

  }

  return noutput_items;

}