1. A method, comprising: determining, by a packet switching device, a packet matches one of a plurality of predetermined patterns which allow for false-positive matching indications of a plurality of underlying rules corresponding to the plurality of predetermined patterns, wherein said determining the packet matches one of the plurality of predetermined patterns includes: determining a first pattern match of a packet when each particular portion of a plurality of different portions of the packet is found to be matching a corresponding particular pattern portion by performing a table lookup operation based on the particular portion as an address in a corresponding different current portion-iteration table to retrieve a corresponding partial result.