WO2001086818A8 - Lzw data compression and decompression apparatus and method using grouped data characters to reduce dictionary accesses - Google Patents

Lzw data compression and decompression apparatus and method using grouped data characters to reduce dictionary accesses

Info

Publication number
WO2001086818A8
WO2001086818A8 PCT/US2001/013729 US0113729W WO0186818A8 WO 2001086818 A8 WO2001086818 A8 WO 2001086818A8 US 0113729 W US0113729 W US 0113729W WO 0186818 A8 WO0186818 A8 WO 0186818A8
Authority
WO
WIPO (PCT)
Prior art keywords
data
character
characters
data characters
grouped
Prior art date
Application number
PCT/US2001/013729
Other languages
French (fr)
Other versions
WO2001086818A3 (en
WO2001086818A2 (en
Inventor
Albert B Cooper
Original Assignee
Unisys Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unisys Corp filed Critical Unisys Corp
Publication of WO2001086818A2 publication Critical patent/WO2001086818A2/en
Publication of WO2001086818A8 publication Critical patent/WO2001086818A8/en
Publication of WO2001086818A3 publication Critical patent/WO2001086818A3/en

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T9/00—Image coding
    • G06T9/005—Statistical coding, e.g. Huffman, run length coding
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/3084—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction using adaptive string matching, e.g. the Lempel-Ziv method
    • H03M7/3088—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction using adaptive string matching, e.g. the Lempel-Ziv method employing the use of a dictionary, e.g. LZ78

Abstract

In a data compressor, the input stream of data characters is formed into one or more data character groupings where each grouping comprises a predetermined number of the data characters (grouped character) followed by one or more of the input data characters. The formed input is compared to similarly configured stored strings until a longest match is determined. Each stored string has a code associated therewith and the code of the longest match is output by the compressor. An extended string is stored comprising the longest match extended by the data character that caused the mismatch. A next compression cycle begins with a grouped character comprising the data character that caused the mismatch concatenated by one less than the predetermined number of the next following data characters.
PCT/US2001/013729 2000-05-04 2001-04-30 Lzw data compression and decompression apparatus and method using grouped data characters to reduce dictionary accesses WO2001086818A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/564,956 2000-05-04
US09/564,956 US6307488B1 (en) 2000-05-04 2000-05-04 LZW data compression and decompression apparatus and method using grouped data characters to reduce dictionary accesses

Publications (3)

Publication Number Publication Date
WO2001086818A2 WO2001086818A2 (en) 2001-11-15
WO2001086818A8 true WO2001086818A8 (en) 2002-04-04
WO2001086818A3 WO2001086818A3 (en) 2002-06-13

Family

ID=24256597

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/013729 WO2001086818A2 (en) 2000-05-04 2001-04-30 Lzw data compression and decompression apparatus and method using grouped data characters to reduce dictionary accesses

Country Status (2)

Country Link
US (1) US6307488B1 (en)
WO (1) WO2001086818A2 (en)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6426711B1 (en) * 2001-05-14 2002-07-30 Unisys Corporation Character table implemented data compression method and apparatus
US6466144B1 (en) * 2001-11-30 2002-10-15 Unisys Corporation Data decompressor for use with a data compressor implemented with limited length character tables and compact string codes
US6628211B1 (en) * 2002-03-19 2003-09-30 Unisys Corporation Prefix table implemented data compression method and apparatus
US6753118B2 (en) * 2002-03-27 2004-06-22 Fitel Usa Corp. Optical grating fabrication process
US7071854B1 (en) * 2002-05-13 2006-07-04 Unisys Corporation Hardware-implemented LZW data decompression
US6608570B1 (en) * 2002-07-15 2003-08-19 Unisys Corporation Matrix implemented data compression apparatus and method
GB0228942D0 (en) * 2002-12-12 2003-01-15 Ibm Linguistic dictionary and method for production thereof
US6674374B1 (en) * 2003-01-25 2004-01-06 Unisys Corporation Data compressor utilizing switched input coincidence elements
US6756923B1 (en) * 2003-05-30 2004-06-29 Unisys Corporation Data compressor utilizing switched input coincidence elements arranged in virtual levels
US7117204B2 (en) * 2003-12-03 2006-10-03 International Business Machines Corporation Transparent content addressable data storage and compression for a file system
US7133963B2 (en) * 2003-12-03 2006-11-07 International Business Machines Corporation Content addressable data storage and compression for semi-persistent computer memory
US7114027B2 (en) * 2003-12-03 2006-09-26 International Business Machines Corporation Content addressable data storage and compression for computer memory
US7117203B2 (en) * 2003-12-03 2006-10-03 International Business Machines Corporation Content addressable data storage and compression for semi-persistent computer memory for a database management system
US7649909B1 (en) 2006-06-30 2010-01-19 Packeteer, Inc. Adaptive tunnel transport protocol
US7443321B1 (en) * 2007-02-13 2008-10-28 Packeteer, Inc. Compression of stream data using a hierarchically-indexed database
EP2378766A1 (en) * 2010-04-16 2011-10-19 Liberty Global Europe Holding B.V. Electronic Program Guide compression method and system
WO2014097359A1 (en) * 2012-12-19 2014-06-26 富士通株式会社 Compression program, compression method, compression device and system
JP6032291B2 (en) * 2012-12-19 2016-11-24 富士通株式会社 Compression program, compression apparatus, decompression program, decompression apparatus, and system
US9015165B1 (en) * 2014-03-03 2015-04-21 Michael L. Hamm Text-SQL relational database
JP6476647B2 (en) * 2014-08-20 2019-03-06 富士通株式会社 Compression program, compression apparatus, compression method, decompression program, decompression apparatus, and decompression method
CN112100455B (en) * 2020-08-18 2022-09-20 北京理工大学 LZW dictionary searching method based on character string parallel search

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4558302A (en) 1983-06-20 1985-12-10 Sperry Corporation High speed data compression and decompression apparatus and method
US5146221A (en) * 1989-01-13 1992-09-08 Stac, Inc. Data compression apparatus and method
GB2301252A (en) * 1995-05-23 1996-11-27 Ibm Run length data compression
US5861827A (en) * 1996-07-24 1999-01-19 Unisys Corporation Data compression and decompression system with immediate dictionary updating interleaved with string search
US6169499B1 (en) * 1999-06-19 2001-01-02 Unisys Corporation LZW data compression/decompression apparatus and method with embedded run-length encoding/decoding
US6188333B1 (en) * 1999-08-12 2001-02-13 Unisys Corporation LZW data compression apparatus and method using look-ahead mathematical run processing

Also Published As

Publication number Publication date
US6307488B1 (en) 2001-10-23
WO2001086818A3 (en) 2002-06-13
WO2001086818A2 (en) 2001-11-15

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