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cuberite-2a/tests/FastRandom/FastRandomTest.cpp

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// FastRandomTest.cpp
// Tests the randomness of cFastRandom
#include "Globals.h"
#include "FastRandom.h"
static void TestInts(void)
{
cFastRandom rnd;
int sum = 0;
const int BUCKETS = 8;
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int Counts[BUCKETS] = {0};
const int ITER = 10000;
for (int i = 0; i < ITER; i++)
{
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int v = rnd.RandInt(1000);
assert_test(v >= 0);
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assert_test(v <= 1000);
Counts[v % BUCKETS]++;
sum += v;
}
double avg = static_cast<double>(sum) / ITER;
LOG("avg: %f", avg);
for (int i = 0; i < BUCKETS; i++)
{
LOG(" bucket %d: %d", i, Counts[i]);
}
}
static void TestFloats(void)
{
cFastRandom rnd;
float sum = 0;
const int BUCKETS = 8;
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int Counts[BUCKETS] = {0};
const int ITER = 10000;
for (int i = 0; i < ITER; i++)
{
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float v = rnd.RandReal(1000.0f);
assert_test(v >= 0);
assert_test(v <= 1000);
Counts[static_cast<int>(v) % BUCKETS]++;
sum += v;
}
sum = sum / ITER;
LOG("avg: %f", sum);
for (int i = 0; i < BUCKETS; i++)
{
LOG(" bucket %d: %d", i, Counts[i]);
}
}
/** Checks whether re-creating the cFastRandom class produces the same initial number over and over (#2935) */
static void TestReCreation(void)
{
const int ITER = 10000;
int lastVal = 0;
int numSame = 0;
int maxNumSame = 0;
for (int i = 0; i < ITER; ++i)
{
cFastRandom rnd;
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int val = rnd.RandInt(9);
if (val == lastVal)
{
numSame += 1;
}
else
{
if (numSame > maxNumSame)
{
maxNumSame = numSame;
}
numSame = 0;
lastVal = val;
}
}
if (numSame > maxNumSame)
{
maxNumSame = numSame;
}
LOG("Out of %d creations, there was a chain of at most %d same numbers generated.", ITER, maxNumSame);
}
int main(void)
{
LOG("FastRandom Test started");
LOG("Testing ints");
TestInts();
LOG("Testing floats");
TestFloats();
LOG("Testing re-creation");
TestReCreation();
LOG("FastRandom test finished");
}