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

/*

 * Copyright 2008 Free Software Foundation, Inc.

 * 

 * 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_decode_ccsds_27_fb.h>

#include <gr_io_signature.h>

gr_decode_ccsds_27_fb_sptr 

gr_make_decode_ccsds_27_fb()

{

  return gr_decode_ccsds_27_fb_sptr(new gr_decode_ccsds_27_fb());

}

gr_decode_ccsds_27_fb::gr_decode_ccsds_27_fb()

  : gr_sync_decimator("decode_ccsds_27_fb",

                      gr_make_io_signature(1, 1, sizeof(float)),

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

                      2*8)  // Rate 1/2 code, unpacked to packed translation

{

    float RATE = 0.5;

    float ebn0 = 12.0;

    float esn0 = RATE*pow(10.0, ebn0/10);

    gen_met(d_mettab, 100, esn0, 0.0, 256);

    viterbi_chunks_init(d_state0);

}

gr_decode_ccsds_27_fb::~gr_decode_ccsds_27_fb()

{

}

int 

gr_decode_ccsds_27_fb::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];

  unsigned char *out = (unsigned char *)output_items[0];

  for (int i = 0; i < noutput_items*16; i++) {

    // Translate and clip [-1.0..1.0] to [28..228]

    float sample = in[i]*100.0+128.0;

    if (sample > 255.0)

        sample = 255.0;

    else if (sample < 0.0)

        sample = 0.0;

    unsigned char sym = (unsigned char)(floor(sample));

    d_viterbi_in[d_count % 4] = sym;

    if ((d_count % 4) == 3) {

      // Every fourth symbol, perform butterfly operation

      viterbi_butterfly2(d_viterbi_in, d_mettab, d_state0, d_state1);

      // Every sixteenth symbol, read out a byte

      if (d_count % 16 == 11) {

        // long metric = 

        viterbi_get_output(d_state0, out++);

        // printf("%li\n", *(out-1), metric);

      }

    }

    d_count++;

  }

  return noutput_items;

}