/**
* Return a context w/ an aggregated count for each counter id.
*
* @param left counter context.
* @param right counter context.
*/
public ByteBuffer merge(ByteBuffer left, ByteBuffer right) {
boolean leftIsSuperSet = true;
boolean rightIsSuperSet = true;
int globalCount = 0;
int localCount = 0;
int remoteCount = 0;
ContextState leftState = ContextState.wrap(left);
ContextState rightState = ContextState.wrap(right);
while (leftState.hasRemaining() && rightState.hasRemaining()) {
int cmp = leftState.compareIdTo(rightState);
if (cmp == 0) {
Relationship rel = compare(leftState, rightState);
if (rel == Relationship.GREATER_THAN) rightIsSuperSet = false;
else if (rel == Relationship.LESS_THAN) leftIsSuperSet = false;
else if (rel == Relationship.DISJOINT) leftIsSuperSet = rightIsSuperSet = false;
if (leftState.isGlobal() || rightState.isGlobal()) globalCount += 1;
else if (leftState.isLocal() || rightState.isLocal()) localCount += 1;
else remoteCount += 1;
leftState.moveToNext();
rightState.moveToNext();
} else if (cmp > 0) {
leftIsSuperSet = false;
if (rightState.isGlobal()) globalCount += 1;
else if (rightState.isLocal()) localCount += 1;
else remoteCount += 1;
rightState.moveToNext();
} else // cmp < 0
{
rightIsSuperSet = false;
if (leftState.isGlobal()) globalCount += 1;
else if (leftState.isLocal()) localCount += 1;
else remoteCount += 1;
leftState.moveToNext();
}
}
if (leftState.hasRemaining()) rightIsSuperSet = false;
else if (rightState.hasRemaining()) leftIsSuperSet = false;
// if one of the contexts is a superset, return it early.
if (leftIsSuperSet) return left;
else if (rightIsSuperSet) return right;
while (leftState.hasRemaining()) {
if (leftState.isGlobal()) globalCount += 1;
else if (leftState.isLocal()) localCount += 1;
else remoteCount += 1;
leftState.moveToNext();
}
while (rightState.hasRemaining()) {
if (rightState.isGlobal()) globalCount += 1;
else if (rightState.isLocal()) localCount += 1;
else remoteCount += 1;
rightState.moveToNext();
}
leftState.reset();
rightState.reset();
return merge(
ContextState.allocate(globalCount, localCount, remoteCount), leftState, rightState);
}
