METHOD OF INCREASING SPEED OF DATA COMPRESSION, COMPUTER FOR INCREASING SPEED OF DATA COMPRESSION, AND COMPUTER PROGRAM THEREFOR

摘要

PROBLEM TO BE SOLVED: To improve performance in data compression and reduce the number of hash collisions in the case where a longest matching character string cannot be found in a search through entries in a bucket chain which has a hash value previously registered in a hash table.SOLUTION: There is provided a method of performing data compression by: applying a hash function to a selected part of a character string to calculate a hash value; and using the hash value to search through entries in a bucket chain to find a longest matching character string. The method includes: acquiring an index indicating that a longest matching character string cannot be found in the search through the entries and thus the search is wasted; and switching the hash function to a different hash function for expanding the selected part of the character string, without reconstructing the hash table, when the index exceeds a predetermined threshold.