Pacquiao can be a boxer/puncher, pressure fighter, counterpuncher or swarmer depends on his opponents style or situations but he preferred to be in a midrange though when he executes what he wants to be in a given situations.
Pac fights as a counterpuncher in a first few rounds against bigger opponents or as pressure fighter against equally the same size opponents. He can swarm his opponents if he feels they are in trouble. He can make his opponents think they are in safe distance but when Pac uses his fast feet to close the gap and unleash his punches then they realize they are not safe at all even in midrange. So they start moving backwards (Cotto & Mosley) making sure they are far enough and this makes the fight looks ugly when the other opponent just trying to survive.