DATA COMPRESSION METHOD AND SYSTEM

A lossless type data compression method employing a dictionary system is suitable for character generator of a game machine and so forth. A working data strings are generated from an original data stream. Two sequential working data strings are combined to form a combined string. A dictionary is generated by registering the combined strings having occurrence frequency higher than a given value with a dictionary number. The combined strings in the data stream are replaced with the dictionary numbers corresponding to the combined strings in the dictionary.