public void with_something_hashed_probability_is_calculated_reasonably()
{
var filter = BloomFilter.FromManagedArray(1024, new IHasher[] { new Murmur2Unsafe(), new XXHashUnsafe() });
filter.Add(Encoding.ASCII.GetBytes("Hi There"));
Assert.IsTrue(filter.ProbabilityOfFalsePositive < 0.000001);
}
public void when_adding_a_string_it_does_not_contain_another()
{
var filter = BloomFilter.FromManagedArray(4096, new IHasher[] { new Murmur2Unsafe(), new XXHashUnsafe() });
filter.Add("Hello There");
Assert.IsFalse(filter.Contains("Hi There"));
}
public void when_adding_a_value_it_contains_it()
{
var filter = BloomFilter.FromManagedArray(4096, new IHasher[] { new Murmur2Unsafe(), new XXHashUnsafe() });
filter.Add(Encoding.ASCII.GetBytes("Hello There"));
Assert.IsTrue(filter.Contains(Encoding.ASCII.GetBytes("Hello There")));
}
private unsafe static void ManagedMemory()
{
Console.WriteLine("Managed Memory");
const int size = (int)(500 * MEGABYTE);
var watch = new Stopwatch();
watch.Start();
var filter = BloomFilter.FromManagedArray(size, new IHasher[] { new Murmur3AUnsafe(), new XXHashUnsafe() });
for (int i = 0; i < 1000000; i++)
{
var bytes = Guid.NewGuid().ToByteArray();
filter.Add(bytes);
if (!filter.Contains(bytes))
{
throw new Exception("broken");
}
if (i % 100000 == 0)
{
Console.Write(".");
}
}
Console.WriteLine();
Console.WriteLine(watch.Elapsed);
}
public void when_hashing_two_items_the_hashed_items_should_be_two()
{
var filter = BloomFilter.FromManagedArray(4096, new IHasher[] { new Murmur2Unsafe(), new XXHashUnsafe() });
filter.Add(Encoding.ASCII.GetBytes("Hello There"));
filter.Add(Encoding.ASCII.GetBytes("Hi There"));
Assert.AreEqual(2, filter.HashedItems);
}
public void with_nothing_hashed_probability_of_false_positive_is_zero()
{
var filter = BloomFilter.FromManagedArray(4096, new IHasher[] { new Murmur2Unsafe(), new XXHashUnsafe() });
Assert.AreEqual(0, filter.ProbabilityOfFalsePositive);
}