srand.c

ecos实时嵌入式操作系统

//=================================================================
//
//        srand.c
//
//        Testcase for C library srand()
//
//=================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
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//####ECOSGPLCOPYRIGHTEND####
//=================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):     ctarpy, jlarmour
// Contributors:  
// Date:          2000-04-30
// Description:   Contains testcode for C library srand() function
//
//
//####DESCRIPTIONEND####

// INCLUDES

#include <stdlib.h>
#include <cyg/infra/testcase.h>


// CONSTANTS

// Max cross correlation value of two sequences of
// different seed
#define X_CORREL 10

// size of arrays to use for testing
#define TEST_SIZE 1024


// FUNCTIONS

static void
test( CYG_ADDRWORD data )
{
    int ctr;
    static int array_1[TEST_SIZE];
    static int array_2[TEST_SIZE];
    static int array_3[TEST_SIZE];
    int hits;
    int fail;


    srand(3);
    for (ctr=0; ctr<TEST_SIZE; ++ctr)
        array_1[ctr] = rand();

    srand(9);
    for (ctr=0; ctr<TEST_SIZE; ++ctr)
        array_2[ctr] = rand();

    srand(3);
    for (ctr=0; ctr<TEST_SIZE; ++ctr)
        array_3[ctr] = rand();

    // Make sure arrays 1 and 3 are the same
    fail = 0;
    for (ctr=0; ctr<TEST_SIZE; ++ctr) {
        if (array_1[ctr] != array_3[ctr])
            ++fail;
    } // for

    CYG_TEST_PASS_FAIL( fail == 0, "resetting the seed to the same value");

    // Check sequences of different seeds are different
    hits = 0;
    for (ctr=0; ctr<TEST_SIZE; ++ctr) {
        if (array_1[ctr] == array_2[ctr])
            ++hits;
    } // for

    CYG_TEST_PASS_FAIL(hits < X_CORREL,
                       "random sequence for different seeds is different");

    CYG_TEST_FINISH("Finished tests from testcase " __FILE__ " for "
                    "C library srand() function");
} // test()

int
main(int argc, char *argv[])
{
    CYG_TEST_INIT();

    CYG_TEST_INFO("Starting tests from testcase " __FILE__ " for C library "
                  "srand() function");

    test(0);

    CYG_TEST_NA("Testing is not applicable to this configuration");
} // main()



// EOF srand.c