HARDWARE DATA COMPRESSOR WITH MULTIPLE STRING MATCH SEARCH HASH TABLES EACH BASED ON DIFFERENT HASH SIZE

摘要

A hardware data compressor. A hardware engine maintains first and second hash tables while it scans an input block of characters to be compressed. The first hash table is indexed by a hash of N characters of the input block. The second hash table is indexed by a hash of M characters of the input block. M is greater than two. N is greater than M. The engine uses the first hash table to search the input block behind a current search target location for a match of at least N characters at the current search target location, and uses the second hash table to search the input block behind the current search target location for a match of at least M characters at the current search target location when no match of at least N characters at the current search target location using the first hash table is found.