intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 98 insertions, 0 deletions

diff --git a/util/random/mersenne32.cpp b/util/random/mersenne32.cpp
new file mode 100644
index 0000000000..cb8aad8b03
--- /dev/null
+++ b/util/random/mersenne32.cpp
@@ -0,0 +1,98 @@
+#include "mersenne32.h"
+
+#include <util/generic/array_size.h>
+#include <util/stream/input.h>
+
+using namespace NPrivate;
+
+#define M 397
+#define MATRIX_A 0x9908b0dfUL
+#define UPPER_MASK 0x80000000UL
+#define LOWER_MASK 0x7fffffffUL
+
+void TMersenne32::InitGenRand(ui32 s) noexcept {
+    mt[0] = s;
+
+    for (mti = 1; mti < N; ++mti) {
+        mt[mti] = (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
+    }
+}
+
+void TMersenne32::InitByArray(const ui32 init_key[], size_t key_length) noexcept {
+    InitGenRand(19650218UL);
+
+    ui32 i = 1;
+    ui32 j = 0;
+    ui32 k = ui32(N > key_length ? N : key_length);
+
+    for (; k; k--) {
+        mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL)) + init_key[j] + j;
+
+        ++i;
+        ++j;
+
+        if (i >= N) {
+            mt[0] = mt[N - 1];
+            i = 1;
+        }
+
+        if (j >= key_length) {
+            j = 0;
+        }
+    }
+
+    for (k = N - 1; k; k--) {
+        mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) - i;
+
+        ++i;
+
+        if (i >= N) {
+            mt[0] = mt[N - 1];
+            i = 1;
+        }
+    }
+
+    mt[0] = 0x80000000UL;
+}
+
+void TMersenne32::InitNext() noexcept {
+    int kk;
+    ui32 y;
+    ui32 mag01[2] = {
+        0x0UL,
+        MATRIX_A,
+    };
+
+    if (mti == N + 1) {
+        InitGenRand(5489UL);
+    }
+
+    for (kk = 0; kk < N - M; ++kk) {
+        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
+        mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
+    }
+
+    for (; kk < N - 1; ++kk) {
+        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
+        mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
+    }
+
+    y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
+    mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
+
+    mti = 0;
+}
+
+TMersenne32::TMersenne32(IInputStream& input)
+    : mti(N + 1)
+{
+    ui32 buf[128];
+
+    input.LoadOrFail(buf, sizeof(buf));
+    InitByArray(buf, Y_ARRAY_SIZE(buf));
+}
+
+#undef M
+#undef MATRIX_A
+#undef UPPER_MASK
+#undef LOWER_MASK