A data compression apparatus of the invention includes a data acquisition unit to acquire n integers from encoding data, an integer division unit to divide each integer of the n integers into a second integer represented by low-order bits whose number of divided bits is b and a first integer represented by high-order bits obtained by excluding the low-order bits from each integer of the n integers and to output n first integers and n second integers, a first encoding unit to encode and output the n first integers as a first code represented by binary data having a number of bits that is a natural-number times the number of unit bits of L, and a second encoding unit to encode and output the n second integers as a second code.

Apparatus and systems, including computer program products, implementing and using techniques for predicate application using partial compression dictionary match. A search strategy is developed for each predicate to be applied to compressed data. The compressed data is searched using the search strategy to locate the compression symbols identified in the search strategy. In response to locating a compression symbol from the search strategy in the compressed data, a respective row and applying the predicate is decompressed and a respective row that matches the predicate is returned to a database engine or an application.

A compression apparatus performs processing of registering a symbol, which is input, in a predetermined entry among a plurality of entries in a case where the symbol is not registered in a first table having the plurality of entries and outputting the symbol and index data indicating non-compression, processing of outputting index data indicating compression and positional information indicating a position of the entry having the symbol registered therein and having a size smaller than a size of the symbol in a case where the symbol has been registered in the table, and processing of changing the size of the positional information depending on usage conditions of the plurality of entries.

A technique to prevent a retrieving process of a conversion rule from taking a longer time is provided. Provided are a conversion table in which a predetermined number of entry regions capable of storing a mapping between first data and second data smaller in size than the first data are included, the predetermined number of entry regions are divided into a plurality of bank regions, and each of the plurality of bank regions includes entry regions smaller in number than the predetermined number, a determination unit configured to uniquely determine, among the plurality of bank regions, a bank region corresponding to the first data, and a processing unit configured to search entry regions of the determined bank region the predetermined number of times each or a smaller number of times than the predetermined number each, output, when the second data corresponding to the first data is stored, the second data, and when the second data corresponding to the first data is not stored, register the second data corresponding to the first data in an entry region in which another piece of second data is not stored and output the first data.

Methods of encoding and decoding data are described wherein the encoding method comprises: receiving a data file and dividing the data file or data stream into one or more data blocks, each data block having a predetermined size N and comprising a sequence of data units, e.g. byte values; and, iteratively encoding the data file into a data key based on a first permutation function and a first dictionary of permutation indices, preferably the encoded data file having a total size that is equal to or smaller than the original data file and preferably the data key having a size that is equal to or smaller than size of a data block. Iteratively encoding the data file comprises one or more encoding iterations, wherein each encoding iteration includes: determining a first permutation index defining a permutation to generate the first input data block from a first ordered data block, the generating including providing at least the first input data block to an input of the first permutation function, and the first ordered data block being obtainable by ordering the first input data block; determining a first permutation dictionary index representing a location in the first dictionary in which the first permutation index is stored; generating a first frequency data block defining the number of occurrences for each potential data value in the input data block, preferably determining the number of occurrences for each potential data value in the input data block and ordering the determined occurrences in a sequence of values in a hierarchical order, e.g. increasing or decreasing order of the data value; processing the frequency data block; and determining an encoded data block, the encoded data block comprising the first permutation dictionary index and the processed frequency data block. The encoding method further comprises outputting the data key comprising the one or more encoded data blocks and, optionally, iteration information.

A method of encoding image data, including: frequency-transforming input image data to generate an array of frequency-transformed input image coefficients by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selecting the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the input image data.

An electronic device includes a decoding subsystem having a symbol decoder and a second symbol resolver with a plurality of local symbol decoders and a symbol selector. The symbol decoder outputs a first symbol decoded from an initial code for which a symbol is available in a block of the compressed data. The second symbol resolver decodes, in each local symbol decoder, substantially in parallel with decoding the first symbol in the symbol decoder, a respective symbol from a subsequent initial code for which a symbol is available in a respective sub-block of the block of the compressed data. The second symbol resolver outputs, by the symbol selector, as a second symbol, one of the respective symbols from the local symbol decoders selected by the symbol selector based on the initial code.

A technique to prevent a retrieving process of a conversion rule from taking a longer time is provided. Provided are a conversion table in which a predetermined number of entry regions capable of storing a mapping between first data and second data smaller in size than the first data are included, the predetermined number of entry regions are divided into a plurality of bank regions, and each of the plurality of bank regions includes entry regions smaller in number than the predetermined number, a determination unit configured to uniquely determine, among the plurality of bank regions, a bank region corresponding to the first data, and a processing unit configured to search entry regions of the determined bank region the predetermined number of times each or a smaller number of times than the predetermined number each, output, when the second data corresponding to the first data is stored, the second data, and when the second data corresponding to the first data is not stored, register the second data corresponding to the first data in an entry region in which another piece of second data is not stored and output the first data.

An electronic device includes a decoding subsystem having a symbol decoder and a second symbol resolver with a plurality of local symbol decoders and a symbol selector. The symbol decoder outputs a first symbol decoded from an initial code for which a symbol is available in a block of the compressed data. The second symbol resolver decodes, in each local symbol decoder, substantially in parallel with decoding the first symbol in the symbol decoder, a respective symbol from a subsequent initial code for which a symbol is available in a respective sub-block of the block of the compressed data. The second symbol resolver outputs, by the symbol selector, as a second symbol, one of the respective symbols from the local symbol decoders selected by the symbol selector based on the initial code.

A computerized method of compressing symbolic information organized into a plurality of documents, each document having a plurality of symbols, includes: (i) automatically identifying a plurality of sequential and non-sequential symbol pairs in an input document; (ii) counting the number of appearances of each unique symbol pair; and (iii) producing a compressed document that includes a replacement symbol at each position associated with one of the plurality of symbol pairs, at least one of which corresponds to a non-sequential symbol pair. For each non-sequential pair the compressed document includes corresponding indicia indicating a distance between locations of the non-sequential symbols of the pair in the input document. In some instances the plurality of symbol pairs includes only those pairs of non-sequential symbols for which the distance between locations of the non-sequential symbols of the pair in the input document is less than a numeric distance cap.