public void HashedCharBufferAddAndRetrieveClashRunOutX()
{
// Allow 1 items in the linear search phase
var buf = new HashedCharBuffer(new HashedCharBufferOptions()
{
NewHashCode = () => new ControllableHashCode(),
InitialCharCapacity = 20,
InitialHashCapacity = 8,
LinearSearchLimit = 1
});
buf.HashCapacity.ShouldBe(8);
// Fix the hash codes to the same value modulo 8
buf.Store("1,Hello");
buf.Store("9,World");
buf.Find("1,Hello").ShouldBe(0);
buf.Find("9,World").ShouldBe(8);
buf.Retrieve(0).ToString().ShouldBe("1,Hello");
buf.Retrieve(8).ToString().ShouldBe("9,World");
// Hash capacity will have doubled to avoid clash of hashes
// 1 % 8 and 9 % 8
// Once we double, we get 16 hash buckets so clash avoided.
buf.HashCapacity.ShouldBe(16);
}
public void HashedCharBufferHashCollision()
{
// Allow only 1 item in the linear search phase
var buf = new HashedCharBuffer(new HashedCharBufferOptions()
{
NewHashCode = () => new ControllableHashCode(),
InitialCharCapacity = 20,
InitialHashCapacity = 16,
LinearSearchLimit = 1
});
buf.Store("1,Hello");
Should.Throw(() =>
{
buf.Store("1,World");
}, typeof(Exception)).Message.ShouldBe("Too many hash collisions. Increase LinearSearchLimit to overcome.");
}
public void HashedCharBufferAddAndRetrieveNoClash()
{
var buf = new HashedCharBuffer(new HashedCharBufferOptions()
{
NewHashCode = () => new DeterministicHashCode(),
InitialCharCapacity = 20,
InitialHashCapacity = 16,
LinearSearchLimit = 3
});
buf.Store("Hello");
buf.Store("World");
buf.Find("Hello").ShouldBe(0);
buf.Find("World").ShouldBe(6);
buf.Retrieve(0).ToString().ShouldBe("Hello");
buf.Retrieve(6).ToString().ShouldBe("World");
}
public void HashedCharBufferAddAndRetrieveClash()
{
var buf = new HashedCharBuffer(new HashedCharBufferOptions()
{
NewHashCode = () => new ControllableHashCode(),
InitialCharCapacity = 20,
InitialHashCapacity = 16,
LinearSearchLimit = 3
});
buf.Store("1,Hello");
buf.Store("1,World");
//// Confirm that both strings the same hashcode.
//buf.HashFunction.HashSequence("1,Hello").ShouldBe(1);
//buf.HashFunction.HashSequence("1,World").ShouldBe(1);
buf.Find("1,Hello").ShouldBe(0);
buf.Find("1,World").ShouldBe(8);
buf.Retrieve(0).ToString().ShouldBe("1,Hello");
buf.Retrieve(8).ToString().ShouldBe("1,World");
}
