Patent ID: 8166041

Claim:
A method of searching a plurality of documents within a search domain, the method comprising: providing a compressed document ID delta list having a series of contiguous, variable length, document ID delta entries, one for each of the plurality of documents that contains a keyword; providing an occurrence count list having a series of contiguous, variable length, keyword occurrence count entries, one for each of at least some of the plurality of documents in the compressed document ID delta list; associating each keyword occurrence count entry with one of a finite set of categories, wherein each category has an occurrence entry size, wherein each keyword occurrence count entry is of a size substantially equal to the occurrence entry size for the associated category, wherein each of the finite set of categories comprises a base value, and wherein each of the entries in the document ID delta list represents a symbol that is a sum of a category base value and the associated document ID delta entry; providing an encoding table used to compress the document ID delta list, a code ordering of the encoding table corresponding to an order of the symbols in the finite set of categories, wherein the symbol that corresponds to each code in the encoding table is calculated based on the code ordering; and searching the plurality of documents by using the compressed document ID delta list and the occurrence count list.