METHOD FOR DATA COMPRESSION HAVING AN IMPROVED ENCODING ALGORITHM WHICH UTILIZES A TOKEN STACKING TECHNIQUE

摘要

The present invention is a data compression method having an improved encoding algorithm which utilizes a token stacking technique. The essential step of the present invention encoding method is constructing a group of stacked tokens. Each stacked token has multiple fields including a substring length counter field and a backward displacement pointer field, where the former is identical among all stacked tokens for serving as the basis in constructing the group of stacked tokens, and the latter is assigned with a respective range of integers. The ranges assigned to the stacked tokens are stacked sequentially without overlapping. The encoding method further comprises the steps of determining a backward displacement pointer for a compressible substring and encoding the backward displacement pointer into a respective stacked token according to the range assigned, such that the backward displacement pointer falls within the range assigned to the respective stacked token. The present invention encoding method is particularly effective in saving the number of bytes required for encoding compressible substrings which are remotely located from their respective previously processed identical substrings because the larger backward displacement pointer can be encoded in a stacked token assigned with a stacked and shifted range of backward displacement pointers.