Patent ID: 6653949
Filing Date: 2003-11-25
Classification: H03M

Abstract:
Data compression apparatus for compressing an input stream of data characters into an output stream of compressed codes, comprisinga plurality of compressor stages each including a plurality of coincidence elements, a coincidence element corresponding to a string comprised of a prefix string of at least one of said data characters followed by an extension character, a prefix string having a prefix code associated therewith, said plurality of coincidence elements providing a respective plurality of coincidence outputs, a coincidence element having inputs responsive, respectively, to a representation of a prefix code and a representation of a character for energizing the coincidence output thereof upon coincidental energization of the inputs thereof, means for assigning a plurality of codes to selected coincidence elements so that energization of a coincidence output of a selected coincidence element provides a representation of the code assigned thereto, means for coupling the provided representations of codes assigned to the coincidence elements of a compressor stage to the prefix code inputs of the coincidence elements of the next following compressor stage, means for fetching a plurality of data characters from said input stream and applying said fetched characters to respective compressor stages, means, at said respective compressor stages, for coupling representations of said fetched characters to the character inputs of the coincidence elements of said respective compressor stages, means for detecting a compressor stage having a particular coincidence element with an energized coincidence output to which a code is not assigned, thereby determining a mismatching compressor stage, and means for outputting the code assigned to the coincidence element with energized coincidence output of the compressor stage prior to said mismatching compressor stage, thereby providing said stream of compressed codes, said means for assigning being operative for assigning a next available code to said particular coincidence element.