/*

 * Copyright 2008 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.

 */

#include <gri_lfsr.h>

#include <qa_gri_lfsr.h>

#include <cppunit/TestAssert.h>

#include <stdio.h>

#include <string.h>

void

qa_gri_lfsr::test_lfsr ()

{

  int mask = 0x19;

  int seed = 0x01;

  int length = 5;

  gri_lfsr lfsr1(mask,seed,length);

  gri_lfsr lfsr2(mask,seed,length);

  unsigned char expected[] = {1, 0, 1, 1, 0, 1, 0, 1, 0, 0};

  for(unsigned int i=0; i<31; i++){

    lfsr1.next_bit();

  }

  // test that after one lfsr cycle we still match out uncycled lfsr

  for (unsigned int i = 0; i < 41; i++) {

    CPPUNIT_ASSERT_EQUAL((int) lfsr1.next_bit(), (int) lfsr2.next_bit());

  }

  // test the known correct values at the given shift offset

  for(unsigned int i=0; i<10; i++){

    CPPUNIT_ASSERT_EQUAL((int) lfsr1.next_bit(), (int) expected[i]);

  }

  // test for register length too long

  CPPUNIT_ASSERT_THROW(gri_lfsr(mask, seed, 32), std::invalid_argument);

}

void

qa_gri_lfsr::test_scrambler()

{

  // CCSDS 7-bit scrambler

  int mask = 0x8A;

  int seed = 0x7F;

  int length = 7;

  gri_lfsr scrambler(mask, seed, length);

  // Impulse (1 and 126 more zeroes)

  unsigned char src[] = 

    { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0 }; // flush bits

  // Impulse response (including leading bits)

  unsigned char expected[] =

    { 1, 1, 1, 1, 1, 1, 1, 

      0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 

      0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 

      0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 

      0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 

      1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 

      0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 

      1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 

      1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, };

  int len = sizeof(src);

  unsigned char actual[len];

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

    actual[i] = scrambler.next_bit_scramble(src[i]);

  CPPUNIT_ASSERT(memcmp(expected, actual, len) == 0);

}

void

qa_gri_lfsr::test_descrambler()

{

  // CCSDS 7-bit scrambler

  int mask = 0x8A;

  int seed = 0x7F;

  int length = 7;

  gri_lfsr descrambler(mask, seed, length);

  // Scrambled sequence (impulse response)

  unsigned char src[] =

    { 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 

      0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 

      0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 

      0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 

      1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 

      0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 

      1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 

      1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0 }; 

  // Original (garbage while synchronizing, them impulse)

  unsigned char expected[] = 

    { 0, 1, 0, 0, 1, 0,

      1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

      0, 0, 0, 0, 0, 0, 0, 0, 0 };

  int len = sizeof(src);

  unsigned char actual[len];

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

    actual[i] = descrambler.next_bit_descramble(src[i]);

  CPPUNIT_ASSERT(memcmp(expected, actual, len) == 0);

}