A note to maintainers on index assumptions: in a single threaded world it would seem intuitive to assume:
producerIndex >= consumerIndex
As an invariant, but in a concurrent, long running settings all of the following need to be considered:
-
consumerIndex > producerIndex : due to counter overflow (unlikey with longs, but easy to reason)
-
consumerIndex > producerIndex : due to consumer FastFlow like implementation discovering the
element before the counter is updated.
-
producerIndex - consumerIndex < 0 : due to above.
-
producerIndex - consumerIndex > Integer.MAX_VALUE : as linked buffers allow constructing queues
with more than Integer.MAX_VALUE elements.
