first commit

Minecraft.World/Random.cpp

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+#include "stdafx.h"	
+#include "Random.h"
+#include "System.h"
+
+Random::Random()
+{
+	// 4J - jave now uses the system nanosecond counter added to a "seedUniquifier" to get an initial seed. Our nanosecond timer is actually only millisecond accuate, so
+	// use QueryPerformanceCounter here instead
+	__int64 seed;
+	QueryPerformanceCounter((LARGE_INTEGER *)&seed);
+	seed += 8682522807148012LL;
+
+	setSeed(seed);
+}
+
+Random::Random(__int64 seed)
+{
+	setSeed(seed);
+}
+
+void Random::setSeed(__int64 s)
+{
+    this->seed = (s ^ 0x5DEECE66DLL) & ((1LL << 48) - 1);
+    haveNextNextGaussian = false;
+}
+
+int Random::next(int bits)
+{
+    seed = (seed * 0x5DEECE66DLL + 0xBLL) & ((1LL << 48) - 1);
+    return (int)(seed >> (48 - bits));
+}
+
+void Random::nextBytes(byte *bytes, unsigned int count)
+{
+	for(unsigned int i = 0; i < count; i++ )
+	{
+		bytes[i] = (byte)next(8);
+	}
+}
+
+double Random::nextDouble()
+{
+
+    return (((__int64)next(26) << 27) + next(27))
+        / (double)(1LL << 53);
+}
+
+double Random::nextGaussian()
+{
+    if (haveNextNextGaussian)
+	{
+        haveNextNextGaussian = false;
+        return nextNextGaussian;
+    }
+	else
+	{
+        double v1, v2, s;
+        do
+		{ 
+            v1 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
+            v2 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
+            s = v1 * v1 + v2 * v2;
+        } while (s >= 1 || s == 0);
+        double multiplier = sqrt(-2 * log(s)/s);
+        nextNextGaussian = v2 * multiplier;
+        haveNextNextGaussian = true;
+        return v1 * multiplier;
+    }
+}
+
+int Random::nextInt()
+{
+	return next(32);
+}
+
+int Random::nextInt(int n)
+{
+    assert (n>0);
+
+
+    if ((n & -n) == n)  // i.e., n is a power of 2
+        return (int)(((__int64)next(31) * n) >> 31); // 4J Stu - Made __int64 instead of long
+
+    int bits, val;
+    do
+	{
+        bits = next(31);
+        val = bits % n;
+    } while(bits - val + (n-1) < 0);
+    return val;
+}
+
+float Random::nextFloat()
+{
+	return next(24) / ((float)(1 << 24));
+}
+
+__int64 Random::nextLong()
+{
+	return ((__int64)next(32) << 32) + next(32);
+}
+
+bool Random::nextBoolean()
+{
+	return next(1) != 0;
+}