64 lines
3 KiB
Text
64 lines
3 KiB
Text
Description
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Pdlzip is a permissively licensed implementation of the lzip data
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compressor, intended for those who can't distribute (or even use) GPL
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licensed Free Software. (The name of pdlzip comes from 'public domain
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lzip'). Pdlzip is written in C and is (hope)fully compatible with lzip 1.4
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or newer.
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Lzip is a lossless data compressor with a user interface similar to the
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one of gzip or bzip2. Lzip can compress about as fast as gzip (lzip -0)
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or compress most files more than bzip2 (lzip -9). Decompression speed is
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intermediate between gzip and bzip2. Lzip is better than gzip and bzip2
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from a data recovery perspective. Lzip has been designed, written and
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tested with great care to replace gzip and bzip2 as the standard
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general-purpose compressed format for unix-like systems.
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The lzip file format is designed for data sharing and long-term archiving,
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taking into account both data integrity and decoder availability:
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* The lzip format provides very safe integrity checking and some data
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recovery means. The lziprecover program can repair bit flip errors
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(one of the most common forms of data corruption) in lzip files,
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and provides data recovery capabilities, including error-checked
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merging of damaged copies of a file.
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* The lzip format is as simple as possible (but not simpler). The
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lzip manual provides the source code of a simple decompressor
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along with a detailed explanation of how it works, so that with
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the only help of the lzip manual it would be possible for a
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digital archaeologist to extract the data from a lzip file long
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after quantum computers eventually render LZMA obsolete.
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* Additionally the lzip reference implementation is copylefted, which
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guarantees that it will remain free forever.
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A nice feature of the lzip format is that a corrupt byte is easier to
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repair the nearer it is from the beginning of the file. Therefore, with
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the help of lziprecover, losing an entire archive just because of a
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corrupt byte near the beginning is a thing of the past.
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Pdlzip is also able to decompress legacy lzma-alone (.lzma) files.
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Lzma-alone is a very bad format; it is essentially a raw LZMA stream.
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If you keep any lzma-alone files, it is advisable to recompress them to
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lzip format. Lziprecover can convert some lzma-alone files to lzip format
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without recompressing.
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Pdlzip includes public domain (de)compression code from the LZMA SDK
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(Software Development Kit) written by Igor Pavlov.
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I would not write non-copylefted software unless it is too simple to be
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worth copylefting it, but one of the uses of the lzip format is the
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interchange of information, and it is therefore desirable that even the
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users of the most non-free platforms can share lzip files with everybody
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else.
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Copyright (C) 2010-2019 Antonio Diaz Diaz.
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This file is free documentation: you have unlimited permission to copy,
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distribute and modify it.
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The file Makefile.in is a data file used by configure to produce the
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Makefile. It has the same copyright owner and permissions that configure
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itself.
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