Abstract: Aspects for generating compressed data streams with lookback pre-fetch instructions are disclosed. A data compression system is provided and configured to receive and compress an uncompressed data stream as part of a lookback-based compression scheme. The data compression system determines if a current data block was previously compressed. If so, the data compression system is configured to insert a lookback instruction corresponding to the current data block into the compressed data stream. Each lookback instruction includes a lookback buffer index that points to an entry in a lookback buffer where decompressed data corresponding to the data block will be stored during a separate decompression scheme. Once the data blocks have been compressed, the data compression system is configured to move a lookback buffer index of each lookback instruction in the compressed data stream into a lookback pre-fetch instruction located earlier than the corresponding lookback instruction in the compressed data stream.

Abstract: Aspects for generating compressed data streams with lookback pre-fetch instructions are disclosed. A data compression system is provided and configured to receive and compress an uncompressed data stream as part of a lookback-based compression scheme. The data compression system determines if a current data block was previously compressed. If so, the data compression system is configured to insert a lookback instruction corresponding to the current data block into the compressed data stream. Each lookback instruction includes a lookback buffer index that points to an entry in a lookback buffer where decompressed data corresponding to the data block will be stored during a separate decompression scheme. Once the data blocks have been compressed, the data compression system is configured to move a lookback buffer index of each lookback instruction in the compressed data stream into a lookback pre-fetch instruction located earlier than the corresponding lookback instruction in the compressed data stream.

Abstract: Data compression systems, methods, and computer program products are disclosed. For each successive input word of an input stream, it is determined whether the input word matches an entry in a lookback table. The lookback table is updated in response to the input word. Input words may be of a number of data types, including zero runs and full or partial matches with an entry in the lookback table. A codeword is generated by entropy encoding a data type corresponding to the input word. The lookback table may be indexed by the position of the input word in the input stream.

Abstract: Data compression systems, methods, and computer program products are disclosed. For each successive input word of an input stream, it is determined whether the input word matches an entry in a lookback table. The lookback table is updated in response to the input word. Input words may be of a number of data types, including zero runs and full or partial matches with an entry in the lookback table. A codeword is generated by entropy encoding a data type corresponding to the input word. The lookback table may be indexed by the position of the input word in the input stream.

Abstract: Lempel-Ziv (LZ)-based data compression employing implicit variable-length distance coding is disclosed. Distances in LZ-based data compression length and distance blocks are implicit variable-length encoded during data compression to avoid padding encoded distances with extra bits (e.g., trailing 0's) that require fewer bits for storage than the number of bits needed to store maximum distance length. This reduces distance bit lengths in compressed output data to further reduce data size. During data compression, a distance table is generated that contains entries each having an assigned base and a number of extra bits to be read in compressed data during data decompression. In this manner, during data decompression, the entries in the distance table can be consulted to determine the number of bits in the variable-encoded distance in the compressed data to be read since the encoded distances can be encoded in the compressed data in fewer bits and without bit padding.