Method for compressing sequential data into compression symbols using double-indirect indexing into a dictionary data structure

摘要

A data compression method compresses a sequence of characters into a sequence of compression symbols by double-indirect indexing into a dictionary data structure arranged in a novel format, wherein the input characters as used as indirect indexes. The dictionary data structure comprises a set of state vectors, arranged in a tree-like structure, and a set of alpha arrays, arranged in a matrix-like structure. During the compression sequence, each character in the sequence is used as an index into a current alpha array, which is used to determine whether the character can be compressed. If compressible, the current alpha array provides an index to a corresponding state vector, which contains information concerning the next alpha array and the next state vector. The next alpha array becomes the next current alpha array, and the next state vector becomes the current state vector. The process is repeated until the sequence of input characters is exhausted or a non- compressible character is encountered. At that time, the compression symbol contained in the current state vector is output as the compression symbol associated with the sequence of input characters.