/// <summary>
/// Atomically sets the element at <paramref name="index"/> to <paramref name="newValue"/>
/// if the current value equals the <paramref name="expectedValue"/>.
/// </summary>
/// <param name="index">
/// The index
/// </param>
/// <param name="expectedValue">
/// The expected value
/// </param>
/// <param name="newValue">
/// The new value
/// </param>
/// <returns>
/// true if successful. False return indicates that
/// the actual value was not equal to the expected value.
/// </returns>
public bool CompareAndSet(int index, T expectedValue, T newValue)
{
ValueHolder <T> current = _atomicReferenceArray[index];
return(Equals(expectedValue, current.Value) &&
(Equals(newValue, current.Value) || _atomicReferenceArray.CompareAndSet(index, current, new ValueHolder <T>(newValue))));
}
public void CompareExistingValueAndSetNewValue()
{
AtomicReferenceArray <T> ai = new AtomicReferenceArray <T>(DEFAULT_COLLECTION_SIZE);
for (int i = 0; i < DEFAULT_COLLECTION_SIZE; ++i)
{
ai.Exchange(i, one);
Assert.IsTrue(ai.CompareAndSet(i, one, two));
Assert.IsTrue(ai.CompareAndSet(i, two, m4));
Assert.AreEqual(m4, ai[i]);
Assert.IsFalse(ai.CompareAndSet(i, m5, seven));
Assert.IsFalse((seven.Equals(ai[i])));
Assert.IsTrue(ai.CompareAndSet(i, m4, seven));
Assert.AreEqual(seven, ai[i]);
}
}
public void CompareAndSetInMultipleThreads()
{
AtomicReferenceArray <T> a = new AtomicReferenceArray <T>(1);
a.Exchange(0, one);
Thread t = ThreadManager.StartAndAssertRegistered(
"T1", () => { while (!a.CompareAndSet(0, two, three))
{
Thread.Sleep(Delays.Short);
}
});
Assert.IsTrue(a.CompareAndSet(0, one, two));
ThreadManager.JoinAndVerify(Delays.Long);
Assert.IsFalse(t.IsAlive);
Assert.AreEqual(a[0], three);
}