Subversion Repositories or1k

//=================================================================

//

//        rand4.c

//

//        Testcase for C library rand()

//

//=================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos 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 2 or (at your option) any later version.

//

// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//=================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):     rosalia

// Contributors:  jlarmour

// Date:          2000-04-30

// Description:   Contains testcode for C library rand() function. This tests

//                that random numbers do not have periodicity in the lower

//                bit

//

//

//####DESCRIPTIONEND####

// CONFIGURATION

#include <pkgconf/libc_stdlib.h>   // Configuration header

// INCLUDES

#include <stdlib.h>

#include <cyg/infra/testcase.h>

// CONSTANTS

#define TEST_LENGTH 100000        // how many samples to take

// DEFINES

#define TEST_VALID (!defined(CYGIMP_LIBC_RAND_SIMPLEST))

// FUNCTIONS

int

main(int argc, char *argv[])

{

#if TEST_VALID

    int i;

    int r, prev, prevprev;

    int how_many_periodics = 0;

#endif

    CYG_TEST_INIT();

    CYG_TEST_INFO("Starting tests from testcase " __FILE__ " for C library "

                  "rand() function");

    CYG_TEST_INFO("This test tests the distribution of random numbers and");

    CYG_TEST_INFO("may take some time");

#if TEST_VALID

    r = rand() % 2;

    prev = r;

    r = rand() % 2;

    for (i = 0; i < TEST_LENGTH; ++i) {

      prevprev = prev;

      prev = r;

      r = rand() % 2;

      if (r == prevprev) {

        ++how_many_periodics;

      }

      if (how_many_periodics > (2*TEST_LENGTH)/3) {

        break;

      }

    }

    CYG_TEST_PASS_FAIL( (how_many_periodics <= (2*TEST_LENGTH)/3),

                        "periodicity of rand() in lowest bit");

#else

    // TODO: should be an _expected_ fail i.e. XFAIL

    CYG_TEST_NA("Chosen rand algorithm is known to fail this test");

#endif

    CYG_TEST_FINISH("Finished tests from testcase " __FILE__ " for "

                    "C library rand() function");

} // main()

// EOF rand4.c