private static bool Add(SmallConcurrentSetOfInts set, int i)
{
bool added = false;
while (true)
{
if (AddHelper(ref set._v1, i, ref added) ||
AddHelper(ref set._v2, i, ref added) ||
AddHelper(ref set._v3, i, ref added) ||
AddHelper(ref set._v4, i, ref added))
{
return(added);
}
var nextSet = set._next;
if (nextSet == null)
{
// Need to add a new 'block'.
SmallConcurrentSetOfInts tail = new SmallConcurrentSetOfInts(initialValue: i);
nextSet = Interlocked.CompareExchange(ref set._next, tail, null);
if (nextSet == null)
{
// Successfully added a new tail
return(true);
}
// Lost the race. Another thread added a new tail so resume searching from there.
}
set = nextSet;
}
}
private static bool Contains(SmallConcurrentSetOfInts set, int i)
{
do
{
// PERF: Not testing for unoccupied slots since it adds complexity. The extra comparisons
// would slow down this inner loop such that any benefit of an 'early out' would be lost.
if (set._v1 == i || set._v2 == i || set._v3 == i || set._v4 == i)
{
return(true);
}
set = set._next;
}while (set != null);
return(false);
}
/// <summary>
/// Insert the given value into the set.
/// </summary>
/// <param name="i">The value to insert</param>
/// <returns>true if <paramref name="i"/> was added. false if it was already present.</returns>
public bool Add(int i)
{
Debug.Assert(i != unoccupied);
return(SmallConcurrentSetOfInts.Add(this, i));
}