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Article #627[comp.sys.mac.programmer] Best text compression
From: Dawson Dean
Date: Sun, 06 Sep 1992 08:25
Date: Sun, 06 Sep 1992 08:25
80 lines
4377 bytes
4377 bytes
Archive-name: auto/comp.sys.mac.programmer/Best-text-compression I sent a message to the original poster last night, but it must have bounced cuz I havent seen it on the net. Then, I see everyone saying how swell Huffman is and I've got to put in my own 2 cents. Its been my experience that a good lzw implementation blows away Huffman and the best public domain lzw I know of is built by Ross Williams, and is called lzrw. There are 5 versions that have different speed/compression tradeoffs, but all are great. You can ftp these from sirius.ucs.adelaide.edu.au or check archie for other archives. Plus, check out comp.compression and comp.compression.research, for the latest scoop from many people (including Ross Williams) who know lots more about this stuff than me. Here is the readMe from the lzrw release.... ---------------- DATA COMPRESSION DIRECTORY ========================== Date : 04-Apr-1992. Author : Ross Williams (ross@spam.ua.oz.au) This file gives an overview of the data compression directory of the anonymous ftp archive located at the University of Adelaide, South Australia. The exact location of the directory is: Machine : sirius.itd.adelaide.edu.au [IP=129.127.40.3] Directory : pub/compression The directory mostly contains public domain data compression algorithms developed by Ross Williams during early 1991. It also contains one or two other items of interest. The files in this directory may be compressed. Files that are compressed will have names terminating with ".Z" and will have to be uncompressed before use (using the Unix "uncompress" command). I wouldn't trust my files to a data compression algorithm :-), but the system programmer who put the files there for me (I do not have direct control over this archive) seems to think that it is a good idea. Ross Williams 21-Aug-1991 0readme - This descriptive file. dc_stan_just - Justification of dc_stan_spec. dc_stan_spec - Proposal for data compression interface standard. dc_stan_stream - Revised proposed standard. dcc91_report - Report on 1991 Data Compression Conference. fast_copy.68000 - Fast block move routine for 68000 microprocessor. lzrw1-a.68000 - LZRW1-A algorithm implemented in 68000 assembler. lzrw1-a.c - LZRW1-A algorithm implemented in C lzrw1-a.txt - Release notes for LZRW1-A algorithm. lzrw1.68000 - LZRW1 algorithm implemented in 68000 assembler. lzrw1.c - LZRW1 algorithm implemented in C. lzrw1.tex - DCC91 conference paper describing LZRW1 algorithm. lzrw2.c - LZRW2 algorithm implemented in C. lzrw2.txt - Release notes for LZRW2 algorithm. lzrw3-a.c - LZRW3-A algorithm implemented in C. lzrw3-a.txt - Release notes for LZRW3-A algorithm. lzrw3.c - LZRW3 algorithm implemented in C. lzrw3.txt - Release notes for LZRW3 algorithm. lzrw4.txt - Description of LZRW4 algorithm (not yet implemented). lzrw45_covering - Release notes for LZRW4 and LZRW5 descriptions. lzrw5.txt - Description of LZRW5 algorithm (not yet implemented). lzrw_headers.h - Header files (.h files) for C code. puzzlebox_provpatent - Provisional patent for puzzle box. rw_info - Information about Ross Williams and his activities. WARNING: A patent has recently arisen that may cover one or more of these algorithms. Please refer to the file rw_info for more information. --<End of 0readme file for the compression directory> -- ****************************************************************** Dawson Dean Internet: dawson@cs.cornell.edu Dept. of Computer Science Office: (607) 255-1179 Cornell University
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Path: arc1-ca.pugleaf.net!sparky!uunet!haven.umd.edu!darwin.sura.net!spool.mu.edu!agate!agate!usenet From: dawson@cs.cornell.edu (Dawson Dean) Newsgroups: comp.archives Subject: [comp.sys.mac.programmer] Best text compression Followup-To: comp.sys.mac.programmer Date: 6 Sep 1992 08:25:12 GMT Organization: Cornell Univ. CS Dept, Ithaca NY 14853 Lines: 81 Approved: adam@soda.berkeley.edu Distribution: world Message-ID: <18cf98INNmpl@agate.berkeley.edu> References: <1992Sep4.150216.26146@cs.cornell.edu> NNTP-Posting-Host: soda.berkeley.edu X-Original-Newsgroups: comp.sys.mac.programmer X-Original-Date: Fri, 4 Sep 1992 15:02:16 GMT