12. A data compression method for compressing a stream of data characters into a stream of compressed codes, comprising storing strings of data characters in storage means, each said string having a code associated therewith, searching said stream of data characters by comparing said stream to said stored strings to perform a character-by-character match therewith until the longest match between said stream of data characters and said stored strings is determined, outputting the code associated with said longest match so as to provide said stream of compressed codes, entering extended strings into said storage means, the entry of said extended strings being interleaved with the matching of the data characters of said character-by-character match, said extended strings comprising the previous longest matched string corresponding to the last outputted code extended by each data character, in turn, as each data character is matched during said character-by-character match, one of said extended strings being entered for each said data character matched and before a next data character is matched during said character-by-character match, the entering of said extended strings during said character-by-character match continuing until said longest match is determined, and assigning respective codes to said extended strings.
12. A data compression method for compressing a stream of data characters into a stream of compressed codes, comprising storing strings of data characters in storage means, each said string having a code associated therewith, searching said stream of data characters by comparing said stream to said stored strings to perform a character-by-character match therewith until the longest match between said stream of data characters and said stored strings is determined, outputting the code associated with said longest match so as to provide said stream of compressed codes, entering extended strings into said storage means, the entry of said extended strings being interleaved with the matching of the data characters of said character-by-character match, said extended strings comprising the previous longest matched string corresponding to the last outputted code extended by each data character, in turn, as each data character is matched during said character-by-character match, one of said extended strings being entered for each said data character matched and before a next data character is matched during said character-by-character match, the entering of said extended strings during said character-by-character match continuing until said longest match is determined, and assigning respective codes to said extended strings. 13. The method of claim 12 wherein said method operates in successive string matching cycles, respective longest matched strings being determined in said successive cycles, a current cycle following a previous cycle, said previous longest matched string being matched in said previous cycle with said last outputted code being provided in said previous cycle, said character-by-character match occurring in said current cycle with said previous longest matched string being extended by said each data character during said current cycle.