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@@ -0,0 +1,66 @@ +Description + +Pdlzip is a permissively licensed implementation of the lzip data +compressor, intended for those who can't distribute (or even use) GPL +licensed Free Software. The name of pdlzip comes from 'public domain lzip'. +Pdlzip is written in C and is compatible with lzip 1.4 or newer. + +Lzip is a lossless data compressor with a user interface similar to the one +of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov +chain-Algorithm' (LZMA) stream format to maximize interoperability. The +maximum dictionary size is 512 MiB so that any lzip file can be decompressed +on 32-bit machines. Lzip provides accurate and robust 3-factor integrity +checking. Lzip can compress about as fast as gzip (lzip -0) or compress most +files more than bzip2 (lzip -9). Decompression speed is intermediate between +gzip and bzip2. Lzip is better than gzip and bzip2 from a data recovery +perspective. Lzip has been designed, written, and tested with great care to +replace gzip and bzip2 as the standard general-purpose compressed format for +Unix-like systems. + +The lzip file format is designed for data sharing and long-term archiving, +taking into account both data integrity and decoder availability: + + * The lzip format provides very safe integrity checking and some data + recovery means. The program lziprecover can repair bit flip errors + (one of the most common forms of data corruption) in lzip files, and + provides data recovery capabilities, including error-checked merging + of damaged copies of a file. + + * The lzip format is as simple as possible (but not simpler). The lzip + manual provides the source code of a simple decompressor along with a + detailed explanation of how it works, so that with the only help of the + lzip manual it would be possible for a digital archaeologist to extract + the data from a lzip file long after quantum computers eventually + render LZMA obsolete. + + * Additionally the lzip reference implementation is copylefted, which + guarantees that it will remain free forever. + +A nice feature of the lzip format is that a corrupt byte is easier to repair +the nearer it is from the beginning of the file. Therefore, with the help of +lziprecover, losing an entire archive just because of a corrupt byte near +the beginning is a thing of the past. + +Pdlzip is also able to decompress legacy lzma-alone (.lzma) files. +Lzma-alone is a very bad format; it is essentially a raw LZMA stream. +If you keep any lzma-alone files, it is advisable to recompress them to +lzip format. Lziprecover can convert some lzma-alone files to lzip format +without recompressing. + +Pdlzip includes public domain compression/decompression code from the LZMA +SDK (Software Development Kit) written by Igor Pavlov. + +I would not write non-copylefted software unless it is too simple to be +worth copylefting it, but one of the uses of the lzip format is the +interchange of information, and it is therefore desirable that even the +users of the most non-free platforms can share lzip files with everybody +else. + + +Copyright (C) 2010-2024 Antonio Diaz Diaz. + +This file is free documentation: you have unlimited permission to copy, +distribute, and modify it. + +The file Makefile.in is a data file used by configure to produce the Makefile. +It has the same copyright owner and permissions that configure itself. |