Compression device, compression method, dictionary generation device, dictionary generation method, decompression device, decompression method, information processing system, and recording medium

Patent metadata

Field	Value
Publication number	US-2016006456-A1
Application number	US-201514857683-A
Country	US
Kind code	A1
Filing date	Sep 17, 2015
Priority date	Mar 22, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A compression device includes a processor configured to execute a process. The process includes: storing dictionary information in which a first compressed code assigned to a plurality of pieces of character information different from one another is associated with the pieces of character information; acquiring, when a first piece of character information among the pieces of character information is acquired, the first compressed code associated with the first piece of character information from the dictionary information; and writing the acquired first compressed code in a storage area to store compressed data.

First claim

What is claimed is:

1 . A compression device comprising:
a processor configured to execute a process including: storing dictionary information in which a plurality of first compressed codes are associated with a plurality of pieces of character information, the plurality of first compressed codes being assigned to the plurality of pieces of character information that are different from one another; acquiring, when a first piece of character information that are included in the plurality of pieces of character information is acquired, the first compressed code associated with the first piece of character information from the dictionary information; and writing the first compressed code in a storage area that stores compressed data.

2 . The compression device according to claim 1 , wherein
the pieces of character information are mutually common in at least a part of a meaning or a grammatical function expressed by the pieces of character information, and the first compressed code is generated based on a total of appearance frequencies of the pieces of character information.

3 . The compression device according to claim 1 , wherein
the dictionary information further associates the first piece of character information with first identifying information that discriminates character information other than the first piece of character information included in the pieces of character information, from the first piece of character information, the acquiring includes acquiring the first compressed code as well as the first identifying information, and the writing includes writing the first compressed code and the first identifying information in the storage area.

4 . The compression device according to claim 3 , wherein
the first identifying information is a compressed code generated based on an appearance frequency of the first piece of character information, and the first compressed code is written subsequent to the first identifying information in the storage area.

5 . The compression device according to claim 3 , wherein the first identifying information is a fixed length compressed code and written subsequent to the first compressed code in the storage area.

6 . A compression method comprising:
acquiring a first compressed code associated with a first piece of character information, by referring to dictionary information in which a plurality of first compressed codes are assigned to a plurality of pieces of character information that are different from one another, the first piece of character information being included in the plurality of pieces of character information, the first compressed code being associated with the first piece of character information in the dictionary information; and writing the acquired first compression code in a storage area to store compressed data.

7 . A non-transitory computer-readable recording medium storing a compression program that causes a computer to execute a process comprising:
acquiring a first compressed code associated with a first piece of character information, by referring to dictionary information in which a plurality of first compressed codes are assigned to a plurality of pieces of character information that are different from one another, the first piece of character information being included in the plurality of pieces of character information, the first compressed code being associated with the first piece of character information in the dictionary information; and writing the acquired first compression code in a storage area to store compressed data.

8 . A decompression device comprising:
a processor configured to execute a process including: storing dictionary information in which a first compressed code assigned in common to a plurality of pieces of character information different from one another is associated with a first piece of character information corresponding to the pieces of character information; acquiring, when the first compressed code is acquired from compressed data, the first piece of character information associated with the first compressed code in the dictionary information, from the dictionary information; and writing the acquired first piece of character information in a storage area to store a decompression result of the compressed data.

9 . The decompression device according to claim 8 , wherein by associating storage destination information that indicates a storage destination of a combination of the first piece of character information and identifying information that discriminates a second piece of character information included in the pieces of character information from character information other than the second piece of character information included in the pieces of character information, with the first compressed code, the dictionary information associates the first compressed code with the first piece of character information.

10 . The decompression device according to claim 9 , wherein
the first compressed code is generated based on a total of appearance frequencies of the pieces of character information, the dictionary information further associates the first compressed code with flag information that indicates that the first compressed code is generated based on the total of the appearance frequencies of the pieces of character information, and the acquiring includes acquiring, when the flag information is associated with the first compressed code in the dictionary information, the first piece of character information by accessing the storage destination based on the storage destination information.

11 . A decompression method comprising:
generating dictionary information in which a first compressed code assigned in common to a plurality of pieces of character information different from one another is associated with a first piece of character information corresponding to the pieces of character information, by a processor; acquiring, when the first compressed code is acquired from compressed data, the first piece of character information associated with the first compressed code in the dictionary information, from the dictionary information, by the processor; and writing the acquired first piece of character information in a storage area to store a decompression result of the compressed data, by the processor.

12 . A non-transitory computer-readable recording medium storing a decompression program that causes a computer to execute a process comprising:
generating dictionary information in which a first compressed code assigned in common to a plurality of pieces of character information is associated with a first piece of character information corresponding to the pieces of character information; acquiring, when the first compressed code is acquired from compressed data, the first piece of character information associated with the first compressed code in the dictionary information, from the dictionary information; and writing the acquired first piece of character information in a storage area to store a decompression result of the compressed data.

13 . An information processing system comprising:
a storage device that stores therein compressed data; and a processing device that executes processing according to a processing request on the compressed data, the processing device including:
a processor configured to execute a process including:
storing dictionary information in which a first compressed code assigned to a plurality of pieces of character information different from one another is associated with the pieces of character information;
reading out the compressed data from the storage device according t

Assignees

• Fujitsu Ltd

Inventors

• Muramatsu chiori
• Nishizawa Shinichiro
• Kataoka Masahiro
• Ldeuchi Masao

Classifications

• G06F16/1744

  using compression, e.g. sparse files · CPC title

• G06F16/86

  Mapping to a database · CPC title

• H03M7/40

  Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code · CPC title

• G06F40/242

  Dictionaries · CPC title

• H03M7/3084 Primary

  using adaptive string matching, e.g. the Lempel-Ziv method · CPC title