private ByteBuffer merge(
ContextState mergedState, ContextState leftState, ContextState rightState) {
while (leftState.hasRemaining() && rightState.hasRemaining()) {
int cmp = leftState.compareIdTo(rightState);
if (cmp == 0) {
Relationship rel = compare(leftState, rightState);
if (rel == Relationship.DISJOINT) // two local shards
mergedState.writeLocal(
leftState.getCounterId(),
leftState.getClock() + rightState.getClock(),
leftState.getCount() + rightState.getCount());
else if (rel == Relationship.GREATER_THAN) leftState.copyTo(mergedState);
else // EQUAL or LESS_THAN
rightState.copyTo(mergedState);
rightState.moveToNext();
leftState.moveToNext();
} else if (cmp > 0) {
rightState.copyTo(mergedState);
rightState.moveToNext();
} else // cmp < 0
{
leftState.copyTo(mergedState);
leftState.moveToNext();
}
}
while (leftState.hasRemaining()) {
leftState.copyTo(mergedState);
leftState.moveToNext();
}
while (rightState.hasRemaining()) {
rightState.copyTo(mergedState);
rightState.moveToNext();
}
return mergedState.context;
}
/**
* Creates a counter context with a single local shard. For use by tests of compatibility with
* pre-2.1 counters only.
*/
public ByteBuffer createLocal(long count) {
ContextState state = ContextState.allocate(0, 1, 0);
state.writeLocal(CounterId.getLocalId(), 1L, count);
return state.context;
}
