Abstract: An apparatus includes a processor that detects a match sequence that matches with a preceding partial sequence in input data, a relative position of the match sequence with respect to the partial sequence, and a match length which is a length of the match sequence; retains the relative position encoded lastly; selects one of a plurality of encoding formats based on closeness indicated by the relative position, the encoding formats being set such that the number of bits to be allocated to the relative position varies among the encoding formats; and encodes the input data by arranging codes in byte unit and omitting, depending on the encoding format selected, the relative position when the relative position is the same as the relative position encoded lastly and retained by the processor.

Abstract: A non-transitory computer-readable storage medium storing a data compressing program that causes a computer to execute a process including when specified log data, including one or a plurality of pieces of numerical data, is obtained, identifying appearance position of one or a plurality of pieces of specific value data appearing in the specified log data specifying pattern data included in at least one piece of pattern data stored in a memory, each of the at least one piece of pattern data indicating a pattern of appearance position of one or a plurality of pieces of specific value data appearing in log data, the appearance position indicated by the specified pattern data perfectly matching or partially matching with the identified appearance position regarding the specified log data, and outputting compressed log data generated by compressing the specified log data, the compressed log data including identifying information indicating the specified pattern data.

Abstract: A data compression apparatus includes a memory and a processor. The processor extracts a second character string as a matching string from a character string after a first character string in a character string of data before compression that is stored in the memory, the second character string being identical with the first character string, and identifies a length of the matching string, and a relative position indicating how many addresses the first character string precedes the second character string by. The processor extracts a third character string having a length that is less than the relative position from the extracted second character string. The processor encodes a length of the third character string. The processor encodes the relative position.

Abstract: A data compression apparatus includes a memory and a processor. The processor extracts a second character string as a matching string from a character string after a first character string in a character string of data before compression that is stored in the memory, the second character string being identical with the first character string, and identifies a length of the matching string, and a relative position indicating how many addresses the first character string precedes the second character string by. The processor extracts a third character string having a length that is less than the relative position from the extracted second character string. The processor encodes a length of the third character string. The processor encodes the relative position.

Abstract: A memory stores a data string to be compressed, which is partitioned into a plurality of blocks, and further stores a plurality of pieces of address information that respectively represent a plurality of addresses within a first block among the plurality of blocks in an order of the plurality of data strings after being rearranged, the plurality of data strings respectively starting at the plurality of addresses within the first block. A processor searches for, in the first block, a first data string that matches a second data string on the basis of the plurality of pieces of address information. When the first data string is not included in the first block, the processor detects the first data string by referring to a second block among the plurality of blocks. The processor encodes and outputs the second data string on the basis of information of the detected first data string.

Abstract: In a data compression apparatus, a search unit examines the sequence of symbols in compression target data, and searches for a second symbol string having the same sequence of symbols as a first symbol string that occurred previously, and a code generation unit encodes the second symbol string into a code containing information that specifies a block to which the beginning of the first symbol string belongs. In a data decompression apparatus, a code acquisition unit sequentially acquires codes from the beginning of the compressed data, and when the code of the second symbol string is acquired, a decompression unit acquires, from a storage device, one or more blocks starting with a block to which the beginning of the decompressed first symbol string belongs, on the basis of the information contained in the acquired code, and decompresses the second symbol string.

Abstract: In a first data compression process, a compressed code of an input symbol is generated in accordance with a compression dictionary selected on the basis of P symbols immediately preceding the input symbol, and a (P+1)K+1-th compressed code is encrypted to generate a compressed and encrypted code. Then, compressed and encrypted data comprising compressed and encrypted codes and other compressed codes is output. In a second data compression process, a bit string is added to the head of compression target data, and a compressed code of an input symbol is generated in accordance with a compression dictionary selected on the basis of a bit string or a symbol immediately preceding the input symbol. Then, a plurality of compressed codes are alternately output to different output destinations.

Abstract: Repetitive portions are sequentially detected in compression target data, and it is determined whether the approximately corresponding position of each repetitive portion is under a word-repetition condition, which is a position corresponding to a multiple of a length of an instruction word, or whether the position is under a byte-repetition condition. When it is under a word-repetition condition, a word-repetition code including at least a value obtained by dividing an approximately corresponding position by an instruction word length and a value specifying a length of a corresponding portion is generated and output as compressed data. When it is a byte-repetition condition, a byte-repetition code including at least a value specifying an approximately corresponding position and a value specifying a length of a corresponding portion is generated and output as compressed data.

Abstract: A bit string having a predetermined length is added to a head of a data string. The data string to which the bit string is added is compressed to produce a compressed data string. A head part is taken off from the compressed data string. The head part includes from a head position of the compressed data string to a predetermined position of the bit string compressed at the compressing. The head part and a latter part of the compressed data are output separately.

Abstract: Structured documents can be compressed without impairing visual recognizability of data structure or flexibility/expandability of structured documents. This invention provides a tag list generating unit for generating a single tag list in which tags in a structured document are listed in the order of appearance, a structured document compressing unit for generating a compressed document in which tags in each of the structured documents are replaced with predetermined delimiter codes, and an outputting unit for outputting the single tag list generated by the tag list generating unit along with a plurality of compressed documents generated from a plurality of structured documents by the structured document compressing unit, in correspondence with one another. This invention is applied to XML and SGML structured documents, and is effective, for example, when a number of slips having the same format are compressed/decompressed.

Abstract: Repetitive portions are sequentially detected in compression target data, and it is determined whether the approximately corresponding position of each repetitive portion is under a word-repetition condition, which is a position corresponding to a multiple of a length of an instruction word, or whether the position is under a byte-repetition condition. When it is under a word-repetition condition, a word-repetition code including at least a value obtained by dividing an approximately corresponding position by an instruction word length and a value specifying a length of a corresponding portion is generated and output as compressed data. When it is a byte-repetition condition, a byte-repetition code including at least a value specifying an approximately corresponding position and a value specifying a length of a corresponding portion is generated and output as compressed data.

Abstract: In a first data compression process, a compressed code of an input symbol is generated in accordance with a compression dictionary selected on the basis of P symbols immediately preceding the input symbol, and a (P+1)K+1-th compressed code is encrypted to generate a compressed and encrypted code. Then, compressed and encrypted data comprising compressed and encrypted codes and other compressed codes is output. In a second data compression process, a bit string is added to the head of compression target data, and a compressed code of an input symbol is generated in accordance with a compression dictionary selected on the basis of a bit string or a symbol immediately preceding the input symbol. Then, a plurality of compressed codes are alternately output to different output destinations.

Abstract: Providing a data compression method, program, and apparatus that allows coding by detecting a repetition of a matching character string even without successiveness of the same numbers in a recent match position list. Using a recent match position list for narrowing down candidates for a matching character string that have previously appeared and to perform detection and coding of a matching character string by performing comparison with each character string in the input buffer as a candidate.

Abstract: This invention provides a structured document processing system comprising: a structured document storage unit for storing a structured document; a partial tree control unit which conceives the structured document stored in the structured document storage unit as a tree structure and controls the tree structure with divided partial trees; an expanding unit which acquires part of the structured document corresponding to a partial tree notified from the partial tree control unit from the structured document storage unit, analyzes part of the acquired structured document from viewpoints of its structure and expands as a hierarchical object in tree structure; and a processing unit for processing the object expanded by the expanding unit following an instruction from a user application.

Abstract: A bit string having a predetermined length is added to a head of a data string. The data string to which the bit string is added is compressed to produce a compressed data string. A head part is taken off from the compressed data string. The head part includes from a head position of the compressed data string to a predetermined position of the bit string compressed at the compressing. The head part and a latter part of the compressed data are output separately.

Abstract: A structured document processing method includes a structured document holding step holding a structured document that includes tags, in a text form, in a memory part, a document information holding step holding document structure information of the structured document and positions of each of the tags of the structured document in a related manner, in the memory part, and a processing step acquiring information related to elements by tracing a tree structure of the structured document according to the document structure information, and acquiring a portion of the structured document based on the information that is acquired.

Abstract: A recent match position list is used for narrowing down candidates for a matching character string that have previously appeared. With a character string of each candidate in an input buffer being compared, a matching character string is detected and coded. An input unit inputs and retains in the input buffer a data string to be compressed. A recent-match-position-list generating unit generates and retains a recent match position list having stored therein a relative position where a character string having a predetermined length starting at each address in the input buffer has most recently appeared. A repetition candidate acquiring unit uses the recent match position list to acquire a repetition candidate for a position where a character string at a coding position has previously appeared.

Abstract: A data compression method, to generate a compressed data stream from an uncompressed data stream, enhances the secrecy of data compression. A scramble value is appended to the beginning of the uncompressed data stream, and a dynamic variable-length encoding method is used to perform data compression. Compressed data with high randomness can be generated, and data for processing can easily be randomized. That is, there is no need to share a common initial value on the generating side and on the restoring side, processing is simple, and the processing time can be shortened.

Abstract: A technique aimed to decrease the resource required for operations on a structured document, decrease the amount of a memory used, and increase the processing speed when the structured document is processed. Elements constituting a structured document to be converted are separated into key elements and nonkey elements, a new element given a predetermined tag name and a predetermined attribute name is created, tag name conversion is performed to create a tag name character string and describe the tag name character string as an attribute value corresponding to the predetermined attribute name in the new element, content conversion is performed to create a content character string including contents of the nonkey elements and describe the content character string as a content of the new element, and the key elements are described unchanged in a converted structured document. The method is applied to a system handling structured documents such as XML.

Abstract: This invention provides a structured document processing system comprising: a structured document storage unit for storing a structured document; a partial tree control unit which conceives the structured document stored in the structured document storage unit as a tree structure and controls the tree structure with divided partial trees; an expanding unit which acquires part of the structured document corresponding to a partial tree notified from the partial tree control unit from the structured document storage unit, analyzes part of the acquired structured document from viewpoints of its structure and expands as a hierarchical object in tree structure; and a processing unit for processing the object expanded by the expanding unit following an instruction from a user application.