rtl.c

Wine-20031016

	} else if (seed < 0x8d79435c) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x9435e50b) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x9af286ba) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xa1af2869) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xa86bca18) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xaf286bc7) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed == 0xaf286bc7) {
	    expected = (expected + 2) & MAXLONG;
	} else if (seed < 0xb5e50d77) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xbca1af26) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xc35e50d5) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xca1af284) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xd0d79433) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xd79435e2) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xde50d792) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xe50d7941) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xebca1af0) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xf286bc9f) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0xf9435e4e) {
	    expected = expected + (seed & 1);
	} else if (seed < 0xfffffffd) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else {
	    expected = expected + (seed & 1);
	} /* if */
        seed_bak = seed;
        result = pRtlUniform(&seed);
        ok(result == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) returns %lx, expected %lx",
                num, seed_bak, result, expected);
        ok(seed == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx",
                num, seed_bak, seed, expected);
    } /* for */
/*
 * Further investigation shows: In the different regions the highest bit
 * is set or cleared when even or odd seeds need an increment by 1.
 * This leads to a simplified algorithm:
 *
 * seed = seed * 0xffffffed + 0x7fffffc3;
 * if (seed == 0xffffffff || seed == 0x7ffffffe) {
 *     seed = (seed + 2) & MAXLONG;
 * } else if (seed == 0x7fffffff) {
 *     seed = 0;
 * } else if ((seed & 0x80000000) == 0) {
 *     seed = seed + (~seed & 1);
 * } else {
 *     seed = (seed + (seed & 1)) & MAXLONG;
 * }
 *
 * This is also the algorithm used for RtlUniform of wine (see dlls/ntdll/rtl.c).
 *
 * Now comes the funny part:
 * It took me one weekend, to find the complicated algorithm and one day more,
 * to find the simplified algorithm. Several weeks later I found out: The value
 * MAXLONG (=0x7fffffff) is never returned, neighter with the native function
 * nor with the simplified algorithm. In reality the native function and our
 * function return a random number distributed over [0..MAXLONG-1]. Note
 * that this is different to what native documentation states [0..MAXLONG].
 * Expressed with D.H. Lehmer's 1948 algorithm it looks like:
 *
 * seed = (seed * const_1 + const_2) % MAXLONG;
 *
 * Further investigations show that the real algorithm is:
 *
 * seed = (seed * 0x7fffffed + 0x7fffffc3) % MAXLONG;
 *
 * This is checked with the test below:
 */
    seed = 0;
    for (num = 0; num <= 100000; num++) {
	expected = (seed * 0x7fffffed + 0x7fffffc3) % 0x7fffffff;
        seed_bak = seed;
        result = pRtlUniform(&seed);
        ok(result == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) returns %lx, expected %lx",
                num, seed_bak, result, expected);
        ok(seed == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx",
                num, seed_bak, seed, expected);
    } /* for */
/*
 * More tests show that RtlUniform does not return 0x7ffffffd for seed values
 * in the range [0..MAXLONG-1]. Additionally 2 is returned twice. This shows
 * that there is more than one cycle of generated randon numbers ...
 */
}


ULONG WINAPI my_RtlRandom(PULONG seed)
{
    static ULONG saved_value[128] =
    { /*   0 */ 0x4c8bc0aa, 0x4c022957, 0x2232827a, 0x2f1e7626, 0x7f8bdafb, 0x5c37d02a, 0x0ab48f72, 0x2f0c4ffa,
      /*   8 */ 0x290e1954, 0x6b635f23, 0x5d3885c0, 0x74b49ff8, 0x5155fa54, 0x6214ad3f, 0x111e9c29, 0x242a3a09,
      /*  16 */ 0x75932ae1, 0x40ac432e, 0x54f7ba7a, 0x585ccbd5, 0x6df5c727, 0x0374dad1, 0x7112b3f1, 0x735fc311,
      /*  24 */ 0x404331a9, 0x74d97781, 0x64495118, 0x323e04be, 0x5974b425, 0x4862e393, 0x62389c1d, 0x28a68b82,
      /*  32 */ 0x0f95da37, 0x7a50bbc6, 0x09b0091c, 0x22cdb7b4, 0x4faaed26, 0x66417ccd, 0x189e4bfa, 0x1ce4e8dd,
      /*  40 */ 0x5274c742, 0x3bdcf4dc, 0x2d94e907, 0x32eac016, 0x26d33ca3, 0x60415a8a, 0x31f57880, 0x68c8aa52,
      /*  48 */ 0x23eb16da, 0x6204f4a1, 0x373927c1, 0x0d24eb7c, 0x06dd7379, 0x2b3be507, 0x0f9c55b1, 0x2c7925eb,
      /*  56 */ 0x36d67c9a, 0x42f831d9, 0x5e3961cb, 0x65d637a8, 0x24bb3820, 0x4d08e33d, 0x2188754f, 0x147e409e,
      /*  64 */ 0x6a9620a0, 0x62e26657, 0x7bd8ce81, 0x11da0abb, 0x5f9e7b50, 0x23e444b6, 0x25920c78, 0x5fc894f0,
      /*  72 */ 0x5e338cbb, 0x404237fd, 0x1d60f80f, 0x320a1743, 0x76013d2b, 0x070294ee, 0x695e243b, 0x56b177fd,
      /*  80 */ 0x752492e1, 0x6decd52f, 0x125f5219, 0x139d2e78, 0x1898d11e, 0x2f7ee785, 0x4db405d8, 0x1a028a35,
      /*  88 */ 0x63f6f323, 0x1f6d0078, 0x307cfd67, 0x3f32a78a, 0x6980796c, 0x462b3d83, 0x34b639f2, 0x53fce379,
      /*  96 */ 0x74ba50f4, 0x1abc2c4b, 0x5eeaeb8d, 0x335a7a0d, 0x3973dd20, 0x0462d66b, 0x159813ff, 0x1e4643fd,
      /* 104 */ 0x06bc5c62, 0x3115e3fc, 0x09101613, 0x47af2515, 0x4f11ec54, 0x78b99911, 0x3db8dd44, 0x1ec10b9b,
      /* 112 */ 0x5b5506ca, 0x773ce092, 0x567be81a, 0x5475b975, 0x7a2cde1a, 0x494536f5, 0x34737bb4, 0x76d9750b,
      /* 120 */ 0x2a1f6232, 0x2e49644d, 0x7dddcbe7, 0x500cebdb, 0x619dab9e, 0x48c626fe, 0x1cda3193, 0x52dabe9d };
    ULONG rand;
    int pos;
    ULONG result;

    rand = (*seed * 0x7fffffed + 0x7fffffc3) % 0x7fffffff;
    *seed = (rand * 0x7fffffed + 0x7fffffc3) % 0x7fffffff;
    pos = *seed & 0x7f;
    result = saved_value[pos];
    saved_value[pos] = rand;
    return(result);
}


static void test_RtlRandom(void)
{
    ULONGLONG num;
    ULONG seed;
    ULONG seed_bak;
    ULONG seed_expected;
    ULONG result;
    ULONG result_expected;

/*
 * Unlike RtlUniform, RtlRandom is not documented. We guess that for
 * RtlRandom D.H. Lehmer's 1948 algorithm is used like stated in
 * the documentation of the RtlUniform function. This algorithm is:
 *
 * seed = (seed * const_1 + const_2) % const_3;
 *
 * According to the RtlUniform documentation the random number is
 * distributed over [0..MAXLONG], but in reality it is distributed
 * over [0..MAXLONG-1]. Therefore const_3 might be MAXLONG + 1 or
 * MAXLONG:
 *
 * seed = (seed * const_1 + const_2) % (MAXLONG + 1);
 *
 * or
 *
 * seed = (seed * const_1 + const_2) % MAXLONG;
 *
 * To find out const_2 we just call RtlRandom with seed set to 0:
 */
    seed = 0;
    result_expected = 0x320a1743;
    seed_expected =0x44b;
    result = pRtlRandom(&seed);
    ok(result == result_expected,
        "pRtlRandom(&seed (seed == 0)) returns %lx, expected %lx",
        result, result_expected);
    ok(seed == seed_expected,
        "pRtlRandom(&seed (seed == 0)) sets seed to %lx, expected %lx",
        seed, seed_expected);
/*
 * Seed is not equal to result as with RtlUniform. To see more we
 * call RtlRandom aggain with seed set to 0:
 */
    seed = 0;
    result_expected = 0x7fffffc3;
    seed_expected =0x44b;
    result = pRtlRandom(&seed);
    ok(result == result_expected,
        "RtlRandom(&seed (seed == 0)) returns %lx, expected %lx",
        result, result_expected);
    ok(seed == seed_expected,
        "RtlRandom(&seed (seed == 0)) sets seed to %lx, expected %lx",
        seed, seed_expected);
/*
 * Seed is set to the same value as before but the result is different.
 * To see more we call RtlRandom aggain with seed set to 0:
 */
    seed = 0;
    result_expected = 0x7fffffc3;
    seed_expected =0x44b;
    result = pRtlRandom(&seed);
    ok(result == result_expected,
        "RtlRandom(&seed (seed == 0)) returns %lx, expected %lx",
        result, result_expected);
    ok(seed == seed_expected,
        "RtlRandom(&seed (seed == 0)) sets seed to %lx, expected %lx",
        seed, seed_expected);
/*
 * Seed is aggain set to the same value as before. This time we also
 * have the same result as before. Interestingly the value of the
 * result is 0x7fffffc3 which is the same value used in RtlUniform
 * as const_2. If we do
 *
 * seed = 0;
 * result = RtlUniform(&seed);
 *
 * we get the same result (0x7fffffc3) as with
 *
 * seed = 0;
 * RtlRandom(&seed);
 * seed = 0;
 * result = RtlRandom(&seed);
 *
 * And there is another interesting thing. If we do
 *
 * seed = 0;
 * RtlUniform(&seed);
 * RtlUniform(&seed);
 *
 * seed is set to the value 0x44b which ist the same value that
 *
 * seed = 0;
 * RtlRandom(&seed);
 *
 * assigns to seed. Putting this two findings together leads to
 * the concluson that RtlRandom saves the value in some variable,
 * like in the following algorithm:
 *
 * result = saved_value;
 * saved_value = RtlUniform(&seed);
 * RtlUniform(&seed);
 * return(result);
 *
 * Now we do further tests with seed set to 1:
 */
    seed = 1;
    result_expected = 0x7a50bbc6;
    seed_expected =0x5a1;
    result = pRtlRandom(&seed);
    ok(result == result_expected,
        "RtlRandom(&seed (seed == 1)) returns %lx, expected %lx",
        result, result_expected);
    ok(seed == seed_expected,
        "RtlRandom(&seed (seed == 1)) sets seed to %lx, expected %lx",
        seed, seed_expected);
/*
 * If there is just one saved_value the result now would be
 * 0x7fffffc3. From this test we can see that there is more than
 * one saved_value, like with this algorithm:
 *
 * result = saved_value[pos];
 * saved_value[pos] = RtlUniform(&seed);
 * RtlUniform(&seed);
 * return(result);
 *
 * But how the value of pos is determined? The calls to RtlUniform
 * create a sequence of random numbers. Every second random number
 * is put into the saved_value array and is used in some later call
 * of RtlRandom as result. The only reasonable source to determine
 * pos are the random numbers generated by RtlUniform which are not
 * put into the saved_value array. This are the values of seed
 * between the two calls of RtlUniform as in this altorithm:
 *
 * rand = RtlUniform(&seed);
 * RtlUniform(&seed);
 * pos = position(seed);
 * result = saved_value[pos];
 * saved_value[pos] = rand;
 * return(result);
 *
 * What remains to determine is: The size of the saved_value array,
 * the initial values of the saved_value array and the function
 * position(seed). This tests are not shown here. 
 * The result of this tests ist: The size of the saved_value array
 * is 128, the initial values can be seen in the my_RtlRandom
 * function and the position(seed) function is (seed & 0x7f).
 *
 * For a full test of RtlRandom use one of the following loop heads:
 *
 *  for (num = 0; num <= 0xffffffff; num++) {
 *      seed = num;
 *      ...
 *
 *  seed = 0;
 *  for (num = 0; num <= 0xffffffff; num++) {
 *      ...
 */
    seed = 0;
    for (num = 0; num <= 100000; num++) {
        seed_bak = seed;
	seed_expected = seed;
        result_expected = my_RtlRandom(&seed_expected);
	/* The following corrections are necessary because the */
	/* previous tests changed the saved_value array */
	if (num == 0) {
	    result_expected = 0x7fffffc3;
        } else if (num == 81) {
	    result_expected = 0x7fffffb1;
	} /* if */
        result = pRtlRandom(&seed);
        ok(result == result_expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) returns %lx, expected %lx",
                num, seed_bak, result, result_expected);
        ok(seed == seed_expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx",
                num, seed_bak, seed, seed_expected);
    } /* for */
}


typedef struct {
    ACCESS_MASK GrantedAccess;
    ACCESS_MASK DesiredAccess;
    BOOLEAN result;
} all_accesses_t;

static const all_accesses_t all_accesses[] = {
    {0xFEDCBA76, 0xFEDCBA76, 1},
    {0x00000000, 0xFEDCBA76, 0},
    {0xFEDCBA76, 0x00000000, 1},
    {0x00000000, 0x00000000, 1},
    {0xFEDCBA76, 0xFEDCBA70, 1},
    {0xFEDCBA70, 0xFEDCBA76, 0},
    {0xFEDCBA76, 0xFEDC8A76, 1},
    {0xFEDC8A76, 0xFEDCBA76, 0},
    {0xFEDCBA76, 0xC8C4B242, 1},
    {0xC8C4B242, 0xFEDCBA76, 0},
};
#define NB_ALL_ACCESSES (sizeof(all_accesses)/sizeof(*all_accesses))


static void test_RtlAreAllAccessesGranted(void)
{
    size_t test_num;
    BOOLEAN result;

    for (test_num = 0; test_num < NB_ALL_ACCESSES; test_num++) {
	result = pRtlAreAllAccessesGranted(all_accesses[test_num].GrantedAccess,
					   all_accesses[test_num].DesiredAccess);
	ok(all_accesses[test_num].result == result,
	   "(test %d): RtlAreAllAccessesGranted(%08lx, %08lx) returns %d, expected %d",
	   test_num, all_accesses[test_num].GrantedAccess,
	   all_accesses[test_num].DesiredAccess,
	   result, all_accesses[test_num].result);
    } /* for */
}


typedef struct {
    ACCESS_MASK GrantedAccess;
    ACCESS_MASK DesiredAccess;
    BOOLEAN result;
} any_accesses_t;

static const any_accesses_t any_accesses[] = {
    {0xFEDCBA76, 0xFEDCBA76, 1},
    {0x00000000, 0xFEDCBA76, 0},
    {0xFEDCBA76, 0x00000000, 0},
    {0x00000000, 0x00000000, 0},
    {0xFEDCBA76, 0x01234589, 0},
    {0x00040000, 0xFEDCBA76, 1},
    {0x00040000, 0xFED8BA76, 0},
    {0xFEDCBA76, 0x00040000, 1},
    {0xFED8BA76, 0x00040000, 0},
};
#define NB_ANY_ACCESSES (sizeof(any_accesses)/sizeof(*any_accesses))


static void test_RtlAreAnyAccessesGranted(void)
{
    size_t test_num;
    BOOLEAN result;

    for (test_num = 0; test_num < NB_ANY_ACCESSES; test_num++) {
	result = pRtlAreAnyAccessesGranted(any_accesses[test_num].GrantedAccess,
					   any_accesses[test_num].DesiredAccess);
	ok(any_accesses[test_num].result == result,
	   "(test %d): RtlAreAnyAccessesGranted(%08lx, %08lx) returns %d, expected %d",
	   test_num, any_accesses[test_num].GrantedAccess,
	   any_accesses[test_num].DesiredAccess,
	   result, any_accesses[test_num].result);
    } /* for */
}

static void test_RtlComputeCrc32()
{
  DWORD crc = 0;

  if (!pRtlComputeCrc32)
    return;

  crc = pRtlComputeCrc32(crc, src, LEN);
  ok(crc == 0x40861dc2,"Expected 0x40861dc2, got %8lx\n", crc);
}

START_TEST(rtl)
{
    InitFunctionPtrs();

    test_RtlCompareMemory();
    test_RtlCompareMemoryUlong();
    test_RtlMoveMemory();
    test_RtlFillMemory();
    test_RtlFillMemoryUlong();
    test_RtlZeroMemory();
    if (pRtlUlonglongByteSwap) {
	test_RtlUlonglongByteSwap();
    } /* if */
    test_RtlUniform();
    test_RtlRandom();
    test_RtlAreAllAccessesGranted();
    test_RtlAreAnyAccessesGranted();
    test_RtlComputeCrc32();
}