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

/*

 * Copyright 2002 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 <cppunit/TestAssert.h>

#include <stdlib.h>

#include <stdio.h>

#include <atsci_reed_solomon.h>

#include <qa_atsci_reed_solomon.h>

#include <string.h>

static const int NROOTS      =   20;

static const int NTRIALS     =  100;

static const int NN             = ATSC_MPEG_RS_ENCODED_LENGTH;

void

qa_atsci_reed_solomon::t0_reed_solomon ()

{

  atsc_mpeg_packet_no_sync        in;

  atsc_mpeg_packet_rs_encoded          enc;

  atsc_mpeg_packet_no_sync        out;

  int                          derrors;

  int                          errlocs[NN];

  int                          errval;

  int                          errloc;

  int                          decoder_errors = 0;

  for (int nt = 0; nt < NTRIALS; nt++){

    // test up to the error correction capacity of the code

    for (int errors = 0; errors <= NROOTS*2; errors++){

      // load block with random data and encode

      for (int i = 0; i < ATSC_MPEG_DATA_LENGTH; i++)

        in.data[i] = random () & 0xff;

      rs.encode (enc, in);

      memset (errlocs, 0, sizeof (errlocs));

      for (int i = 0; i < errors; i++){

        do {

          errval = random () & 0xff;

        } while (errval == 0);        // error value must be non-zero

        do {

          errloc = random () % NN;

        } while (errlocs[errloc] != 0);                // must not choose the same location twice

        errlocs[errloc] = 1;

        enc.data[errloc] ^= errval;                // cause the error

      }

      // decode the errored block

      derrors = rs.decode (out, enc);

      if (errors <= NROOTS/2) {

        // We should have handled all these errors and corrected them.

        if (derrors != errors){

          fprintf (stderr, "  decoder says %d errors, true number is %d\n", derrors, errors);

          decoder_errors++;

        }

        if (in != out){

          fprintf (stderr, "  uncorrected errors!\n");

          decoder_errors++;

        }

      } else {

        // We have been given more errors than we could cope with.  Make

        // sure that we detect these errors.  Complain if we get incorrect

        // block but don't say it's incorrect.

        bool differs = (in != out);

        if (differs && (derrors < 0)) {

          // Reported uncorrectable error accurately

        } else if (differs) {

          fprintf (stderr,

                   "  decoder found %d of %d errors, but incorrect block\n",

                   derrors, errors);

        } else {

          fprintf (stderr, "  decoder corrected %d of %d errors unexpectedly\n",

                   derrors, errors);

        }

      }

    }

  }

  CPPUNIT_ASSERT (decoder_errors == 0);

}