Patent ID: 8130763

Claim:
A data item interval identifier lookup method for use on a data processing system for performing an interval identifier lookup function for an input data item; wherein the entire value range of the input data item is predefined into a series of consecutive intervals each assigned to a unique identifier, and wherein the interval identifier lookup function is used to find a corresponding identifier for the input data item; the data item interval identifier lookup method comprising: building a multi-stage lookup table module, which includes a plurality of cascaded stages of lookup table data structures, which are established by firstly partitioning the entire value range of the input data item into a number of segments, and secondly building a mapping relation for each lookup table data structure based on a predefined interval-and-identifier definition table in reference to the partitioned segments of the input data item, wherein each of the lookup table data structure comprises a mapped item including an identifier-range and link specifier used for specifying both a corresponding identifier range and a link to -a single interval identifier lookup table, wherein the single interval identifier lookup table corresponds to the predefined interval-and-identifier definition table; during actual operation, reading the input data item for the value of each of the partitioned segments of the input data item for use as a set of lookup keys, wherein one of the lookup keys is the entire value of the input data item; and using the lookup keys to inquire the multi-stage lookup table module to find a corresponding interval identifier for the input data item.