Data compression system with expanding window

摘要

A method for compressing a block of input data of predetermined length into a compressed block of output which the use of an expanding input data window. The distance, position and length parameters of each matching string found in the expanding input data window are stored as a combined value which have a one-to-one correspondence to both the distance and length of any given point in the input data block. The combined values can be further encoded by use of a Huffman technique or any other appropriate statistical encoding technique. The combining of a matching string's distance and length parameters into a single value takes advantage of the correlation between the distance and length parameters. This correlation allows the single combined value of distance and length to be more efficiently encoded when using statistical encoding techniques. The technique is especially well adapted to compressing blocks of data of relatively small length. The organization of the code in the manner described results in higher compression and a faster implementation.