rtl.c

winNT技术操作系统,国外开放的原代码和LIUX一样

 *
 * If that does not work a search loop can try all possible values of
 * const_1 and compare to the result to RtlUniform(1).
 * This way we find out that const_1 is 0xffffffed.
 *
 * For seed = 1 the const_2 is 0x7fffffc4:
 */
    seed = 1;
    expected = seed * 0xffffffed + 0x7fffffc3 + 1;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 1)) returns %lx, expected %lx\n",
        result, expected);
/*
 * For seed = 2 the const_2 is 0x7fffffc3:
 */
    seed = 2;
    expected = seed * 0xffffffed + 0x7fffffc3;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 2)) returns %lx, expected %lx\n",
        result, expected);
/*
 * More tests show that if seed is odd the result must be incremented by 1:
 */
    seed = 3;
    expected = seed * 0xffffffed + 0x7fffffc3 + (seed & 1);
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 2)) returns %lx, expected %lx\n",
        result, expected);

    seed = 0x6bca1aa;
    expected = seed * 0xffffffed + 0x7fffffc3;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 0x6bca1aa)) returns %lx, expected %lx\n",
        result, expected);

    seed = 0x6bca1ab;
    expected = seed * 0xffffffed + 0x7fffffc3 + 1;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 0x6bca1ab)) returns %lx, expected %lx\n",
        result, expected);
/*
 * When seed is 0x6bca1ac there is an exception:
 */
    seed = 0x6bca1ac;
    expected = seed * 0xffffffed + 0x7fffffc3 + 2;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 0x6bca1ac)) returns %lx, expected %lx\n",
        result, expected);
/*
 * Note that up to here const_3 is not used
 * (the highest bit of the result is not set).
 *
 * Starting with 0x6bca1ad: If seed is even the result must be incremented by 1:
 */
    seed = 0x6bca1ad;
    expected = (seed * 0xffffffed + 0x7fffffc3) & MAXLONG;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 0x6bca1ad)) returns %lx, expected %lx\n",
        result, expected);

    seed = 0x6bca1ae;
    expected = (seed * 0xffffffed + 0x7fffffc3 + 1) & MAXLONG;
    result = pRtlUniform(&seed);
    ok(result == expected,
        "RtlUniform(&seed (seed == 0x6bca1ae)) returns %lx, expected %lx\n",
        result, expected);
/*
 * There are several ranges where for odd or even seed the result must be
 * incremented by 1. You can see this ranges in the following test.
 *
 * For a full test 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++) {

	expected = seed * 0xffffffed + 0x7fffffc3;
	if (seed < 0x6bca1ac) {
	    expected = expected + (seed & 1);
	} else if (seed == 0x6bca1ac) {
	    expected = (expected + 2) & MAXLONG;
	} else if (seed < 0xd79435c) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x1435e50b) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x1af286ba) { 
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x21af2869) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x286bca18) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x2f286bc7) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x35e50d77) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x3ca1af26) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x435e50d5) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x4a1af284) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x50d79433) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x579435e2) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x5e50d792) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x650d7941) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x6bca1af0) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x7286bc9f) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x79435e4e) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed < 0x7ffffffd) {
	    expected = expected + (seed & 1);
	} else if (seed < 0x86bca1ac) {
	    expected = (expected + (~seed & 1)) & MAXLONG;
	} else if (seed == 0x86bca1ac) {
	    expected = (expected + 1) & MAXLONG;
	} 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\n",
                num, seed_bak, result, expected);
        ok(seed == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx\n",
                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, neither 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 from 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\n",
                num, seed_bak, result, expected);
        ok(seed == expected,
                "test: %llu RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx\n",
                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 ...
 */
}


static 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\n",
        result, result_expected);
    ok(seed == seed_expected,
        "pRtlRandom(&seed (seed == 0)) sets seed to %lx, expected %lx\n",
        seed, seed_expected);
/*
 * Seed is not equal to result as with RtlUniform. To see more we