André Hentschel : ntdll/tests: Simplify the RtlRandom test.
Module: wine Branch: master Commit: c6b888f16f65db07172131f705a4be4a8c35b219 URL: http://source.winehq.org/git/wine.git/?a=commit;h=c6b888f16f65db07172131f705... Author: André Hentschel <nerv(a)dawncrow.de> Date: Tue Sep 15 21:43:44 2015 +0200 ntdll/tests: Simplify the RtlRandom test. --- dlls/ntdll/tests/rtl.c | 222 ++----------------------------------------------- 1 file changed, 8 insertions(+), 214 deletions(-) diff --git a/dlls/ntdll/tests/rtl.c b/dlls/ntdll/tests/rtl.c index 9a4ec48..ce23310 100644 --- a/dlls/ntdll/tests/rtl.c +++ b/dlls/ntdll/tests/rtl.c @@ -657,46 +657,11 @@ static void test_RtlUniform(void) } -static ULONG 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; + int i, j; ULONG seed; - ULONG seed_bak; - ULONG seed_expected; - ULONG result; - ULONG result_expected; + ULONG res[512]; if (!pRtlRandom) { @@ -704,185 +669,14 @@ static void test_RtlRandom(void) return; } -/* - * 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); - -/* - * Windows Vista uses different algorithms, so skip the rest of the tests - * until that is figured out. Trace output for the failures is about 10.5 MB! - */ - - if (seed == 0x3fc) { - skip("Most likely running on Windows Vista which uses a different algorithm\n"); - return; + for (i = 0; i < sizeof(res) / sizeof(res[0]); i++) + { + res[i] = pRtlRandom(&seed); + ok(seed != res[i], "%i: seed is same as res %x\n", i, seed); + for (j = 0; j < i; j++) + ok(res[i] != res[j], "res[%i] (%x) is same as res[%i] (%x)\n", j, res[j], i, res[i]); } - - ok(result == result_expected, - "pRtlRandom(&seed (seed == 0)) returns %x, expected %x\n", - result, result_expected); - ok(seed == seed_expected, - "pRtlRandom(&seed (seed == 0)) sets seed to %x, expected %x\n", - seed, seed_expected); -/* - * Seed is not equal to result as with RtlUniform. To see more we - * call RtlRandom again 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 %x, expected %x\n", - result, result_expected); - ok(seed == seed_expected, - "RtlRandom(&seed (seed == 0)) sets seed to %x, expected %x\n", - seed, seed_expected); -/* - * Seed is set to the same value as before but the result is different. - * To see more we call RtlRandom again 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 %x, expected %x\n", - result, result_expected); - ok(seed == seed_expected, - "RtlRandom(&seed (seed == 0)) sets seed to %x, expected %x\n", - seed, seed_expected); -/* - * Seed is again 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 these two findings together leads to - * the conclusion 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 %x, expected %x\n", - result, result_expected); - ok(seed == seed_expected, - "RtlRandom(&seed (seed == 1)) sets seed to %x, expected %x\n", - 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 is the value of pos 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 algorithm: - * - * rand = RtlUniform(&seed); - * RtlUniform(&seed); - * pos = position(seed); - * result = saved_value[pos]; - * saved_value[pos] = rand; - * return(result); - * - * What remains to be determined is: The size of the saved_value array, - * the initial values of the saved_value array and the function - * position(seed). These tests are not shown here. - * The result of these tests is: 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: 0x%x%08x RtlRandom(&seed (seed == %x)) returns %x, expected %x\n", - (DWORD)(num >> 32), (DWORD)num, seed_bak, result, result_expected); - ok(seed == seed_expected, - "test: 0x%x%08x RtlRandom(&seed (seed == %x)) sets seed to %x, expected %x\n", - (DWORD)(num >> 32), (DWORD)num, seed_bak, result, seed_expected); - } /* for */ }
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Alexandre Julliard