Data compression

Abstract

A method for augmenting a dictionary of a data compression scheme. For each input string, the result of a sliding window search is compared to the result of a dictionary search. The dictionary is augmented with the sliding window search result if the sliding window search result is longer than the dictionary search result. An embodiment of the disclosure implements multiple sliding windows, each sliding window having an associated size, the size of sliding window dependent on a corresponding match length. For one embodiment, each sliding window has a corresponding hash function based upon thematch length.

Description

Background technique [0001] The present disclosure relates generally to the fields of data transmission and storage, and more particularly to data compression and decompression. [0002] In digital systems, data can be compressed to save storage costs or reduce transmission times. A wide variety of digital data signals (eg, data files, documents, images, etc.) can be compressed. Compression improves system performance and reduces costs by reducing the memory required for data storage and / or the time required for data transfer. [0003] Some well-known and widely used lossless compression schemes employ dictionary-based compression, which exploits the fact that many data types contain repeated sequences of characters. One conventional algorithm, LZ77, achieves compression by replacing repeated occurrences of data with a reference to a single copy of that data that existed earlier in the uncompressed data stream. Recurring data (string matches) are encoded by a pair of number...

AI Technical Summary

Problems solved by technology

[0012] Also, larger sliding windows can make it inefficient to store references for smaller matches

Furthermore, the usual dictionary-based schemes are serial in nature and do not take advantage of the parallel processing available in many processor architectures, resulting in poor performance

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