/// <summary>
/// Atomically sets the value of the mark to the given update value
/// if the current value and the expected value <see cref="AreEqual"/>.
/// Any given invocation of this operation may fail
/// (return false) spuriously, but repeated invocation
/// when the current value holds the expected value and no other
/// thread is also attempting to set the value will eventually
/// succeed.
/// </summary>
/// <param name="expectedValue">
/// The expected value
/// </param>
/// <param name="newMark">
/// The new value for the mark
/// </param>
/// <returns>
/// <c>true</c> if successful, <c>false</c> otherwise
/// </returns>
public bool AttemptMark(T expectedValue, bool newMark)
{
ValueBooleanPair current = Pair;
return(AreEqual(expectedValue, current._value) &&
(newMark == current._markBit || _atomicReference.CompareAndSet(current, new ValueBooleanPair(expectedValue, newMark))));
}
/// <summary>
/// Atomically sets both the value and mark to the given update values if the
/// current value and <paramref name="expectedValue"/> <see cref="AreEqual"/>
/// and the current mark is equal to the <paramref name="expectedMark"/>.
/// </summary>
/// <param name="expectedValue">
/// The expected value
/// </param>
/// <param name="newValue">
/// The new value
/// </param>
/// <param name="expectedMark">
/// The expected value of the mark
/// </param>
/// <param name="newMark">
/// The new value for the mark
/// </param>
/// <returns>
/// <c>true</c> if successful, <c>false</c> otherwise
/// </returns>
public bool CompareAndSet(T expectedValue, T newValue, bool expectedMark, bool newMark)
{
ValueBooleanPair current = Pair;
return(AreEqual(expectedValue, current._value) && expectedMark == current._markBit &&
((AreEqual(newValue, current._value) && newMark == current._markBit) || _atomicReference.CompareAndSet(current, new ValueBooleanPair(newValue, newMark))));
}
/// <summary>
/// Returns both the current value and the current mark.
/// Typical usage is:
/// <code>
/// bool isMarked;
/// var reference = v.GetValue(out isMarked);
/// </code>
/// </summary>
/// <param name="isMarked">
/// return the value of the mark.
/// </param>
/// <returns>
/// The current value.
/// </returns>
public T GetValue(out bool isMarked)
{
ValueBooleanPair p = Pair;
isMarked = p._markBit;
return(p._value);
}
/// <summary>
/// Unconditionally sets both the value and mark if any of them are
/// not equal. Method <see cref="AreEqual"/> is used to compare the
/// value.
/// </summary>
/// <param name="newValue">the new value
/// </param>
/// <param name="newMark">the new value for the mark
/// </param>
public void SetNewAtomicValue(T newValue, bool newMark)
{
ValueBooleanPair current = Pair;
if (!AreEqual(newValue, current._value) || newMark != current._markBit)
{
_atomicReference.Exchange(new ValueBooleanPair(newValue, newMark));
}
}
