Techniques to accelerate lossless compression

Computer-readable memory storing one or more instructions that when executed by a machine results in circuitry performing operations comprising at least one of the following subparagraphs (a) to (d):

• (a) indicating, at least in part, in a data structure, at least one position of at least one subset of characters, the characters to be encoded as a symbol as a result of compression encoding, the at least one position being within one or more portions of an input data buffer, the at least one subset comprising less than an entirety of the characters, a respective position of a remaining portion of the characters being unindicated in the data structure, the remaining portion being other than the at least one subset of the characters;
• (b) comparing, at least in part, at least one pair of multi-byte data words, each of the multi-byte words being of identical predetermined fixed size, the comparing being based at least in part upon at least one exclusive-or (XOR) operation involving the at least one pair of the two multi-byte data words, and if at least one mis-compare occurs as a result, at least in part, of the at least one XOR operation, the comparing comprises determining, at least in part, a first location in one of the two multi-byte words at which the at least one mis-compare occurs;
• (c) maintaining, at least in part, an array of pointers to potentially matching strings, the potentially matching strings to be compared by the circuitry with at least one currently examined string until a longest match in bytes is found between a potentially matching string and the at least one currently examined string;
• and
• (d) allocating, at least in part, a first buffer portion to store at least one portion of uncompressed data from an application buffer that is to be input for compression to produce a compressed data stream, the at least one portion of the uncompressed data having been most recently previously input for the compression, a second buffer portion being to store at least one other portion of the uncompressed data that currently is being input for the compression, corresponding strings in the first buffer portion and the second buffer portion to be compared, at least in part, to determine presence of at least one reference to be used, at least in part, in generating the compressed data stream, the first buffer portion and the second buffer portion being comprised in a single buffer.

A method implemented, at least in part, using circuitry, the method comprising at least one of the following subparagraphs (a) to (d):

• (a) indicating in a data structure at least one position of a first subset of characters from a set of characters within one or more portions of an input data buffer, while a position of a second subset of characters remains unindicated in the data structure, the set of characters to be encoded as a symbol through compression encoding;
• (b) comparing at least one pair of multi-byte data words of an identical fixed size based upon an exclusive-or (XOR) operation, and when a mis-compare occurs as a result of the at least one XOR operation, the comparing comprises determining a first location in one of the pair of multi-byte words at which the mis-compare occurs;
• (c) maintaining an array of pointers to potentially matching strings to be compared by the circuitry with at least one currently examined string until a longest match in bytes is found between a potentially matching string and the at least one currently examined string;
• and
• (d) allocating a first buffer portion to store one portion of uncompressed data from an application buffer that is input for compression to produce a compressed data stream, the one portion of uncompressed data having been most recently previously input for the compression, and a second buffer portion to store one other portion of the uncompressed data that is input for the compression, corresponding strings in the first buffer portion and the second buffer portion to be compared to determine presence of at least one reference to be used in generating the compressed data stream, the first buffer portion and the second buffer portion comprising a single buffer.