public Relationship diff()

in src/java/org/apache/cassandra/db/context/CounterContext.java [197:288]
72 lines of code
26 McCabe index (conditional complexity)

    public Relationship diff(ByteBuffer left, ByteBuffer right)
    {
        Relationship relationship = Relationship.EQUAL;
        ContextState leftState = ContextState.wrap(left);
        ContextState rightState = ContextState.wrap(right);

        while (leftState.hasRemaining() && rightState.hasRemaining())
        {
            // compare id bytes
            int compareId = leftState.compareIdTo(rightState);
            if (compareId == 0)
            {
                long leftClock  = leftState.getClock();
                long rightClock = rightState.getClock();
                long leftCount = leftState.getCount();
                long rightCount = rightState.getCount();

                // advance
                leftState.moveToNext();
                rightState.moveToNext();

                // process clock comparisons
                if (leftClock == rightClock)
                {
                    if (leftCount != rightCount)
                    {
                        // Inconsistent shard (see the corresponding code in merge()). We return DISJOINT in this
                        // case so that it will be treated as a difference, allowing read-repair to work.
                        return Relationship.DISJOINT;
                    }
                }
                else if ((leftClock >= 0 && rightClock > 0 && leftClock > rightClock)
                      || (leftClock < 0 && (rightClock > 0 || leftClock < rightClock)))
                {
                    if (relationship == Relationship.EQUAL)
                        relationship = Relationship.GREATER_THAN;
                    else if (relationship == Relationship.LESS_THAN)
                        return Relationship.DISJOINT;
                    // relationship == Relationship.GREATER_THAN
                }
                else
                {
                    if (relationship == Relationship.EQUAL)
                        relationship = Relationship.LESS_THAN;
                    else if (relationship == Relationship.GREATER_THAN)
                        return Relationship.DISJOINT;
                    // relationship == Relationship.LESS_THAN
                }
            }
            else if (compareId > 0)
            {
                // only advance the right context
                rightState.moveToNext();

                if (relationship == Relationship.EQUAL)
                    relationship = Relationship.LESS_THAN;
                else if (relationship == Relationship.GREATER_THAN)
                    return Relationship.DISJOINT;
                // relationship == Relationship.LESS_THAN
            }
            else // compareId < 0
            {
                // only advance the left context
                leftState.moveToNext();

                if (relationship == Relationship.EQUAL)
                    relationship = Relationship.GREATER_THAN;
                else if (relationship == Relationship.LESS_THAN)
                    return Relationship.DISJOINT;
                // relationship == Relationship.GREATER_THAN
            }
        }

        // check final lengths
        if (leftState.hasRemaining())
        {
            if (relationship == Relationship.EQUAL)
                return Relationship.GREATER_THAN;
            else if (relationship == Relationship.LESS_THAN)
                return Relationship.DISJOINT;
        }

        if (rightState.hasRemaining())
        {
            if (relationship == Relationship.EQUAL)
                return Relationship.LESS_THAN;
            else if (relationship == Relationship.GREATER_THAN)
                return Relationship.DISJOINT;
        }

        return relationship;
    }