Description Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip decompresses almost as fast as gzip and compresses more than bzip2, which makes it well suited for software distribution and data archiving. Lzip is a clean implementation of the LZMA algorithm. The lzip file format is designed for long-term data archiving and provides very safe integrity checking. The member trailer stores the 32-bit CRC of the original data, the size of the original data and the size of the member. These values, together with the value remaining in the range decoder and the end-of-stream marker, provide a 4 factor integrity checking which guarantees that the decompressed version of the data is identical to the original. This guards against corruption of the compressed data, and against undetected bugs in lzip (hopefully very unlikely). The chances of data corruption going undetected are microscopic. Be aware, though, that the check occurs upon decompression, so it can only tell you that something is wrong. It can't help you recover the original uncompressed data. If you ever need to recover data from a damaged lzip file, try the lziprecover program. Lziprecover makes lzip files resistant to bit-flip (one of the most common forms of data corruption), and provides data recovery capabilities, including error-checked merging of damaged copies of a file. Lzip uses the same well-defined exit status values used by bzip2, which makes it safer than compressors returning ambiguous warning values (like gzip) when it is used as a back end for tar or zutils. Lzip replaces every file given in the command line with a compressed version of itself, with the name "original_name.lz". Each compressed file has the same modification date, permissions, and, when possible, ownership as the corresponding original, so that these properties can be correctly restored at decompression time. Lzip is able to read from some types of non regular files if the "--stdout" option is specified. If no file names are specified, lzip compresses (or decompresses) from standard input to standard output. In this case, lzip will decline to write compressed output to a terminal, as this would be entirely incomprehensible and therefore pointless. Lzip will correctly decompress a file which is the concatenation of two or more compressed files. The result is the concatenation of the corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported. Lzip can produce multi-member files and safely recover, with lziprecover, the undamaged members in case of file damage. Lzip can also split the compressed output in volumes of a given size, even when reading from standard input. This allows the direct creation of multivolume compressed tar archives. Lzip is able to compress and decompress streams of unlimited size by automatically creating multi-member output. The members so created are large, about 64 PiB each. Lzip will automatically use the smallest possible dictionary size without exceeding the given limit. Keep in mind that the decompression memory requirement is affected at compression time by the choice of dictionary size limit. Lzip implements a simplified version of the LZMA (Lempel-Ziv-Markov chain-Algorithm) algorithm. The high compression of LZMA comes from combining two basic, well-proven compression ideas: sliding dictionaries (LZ77/78) and markov models (the thing used by every compression algorithm that uses a range encoder or similar order-0 entropy coder as its last stage) with segregation of contexts according to what the bits are used for. The ideas embodied in lzip are due to (at least) the following people: Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for the definition of Markov chains), G.N.N. Martin (for the definition of range encoding), Igor Pavlov (for putting all the above together in LZMA), and Julian Seward (for bzip2's CLI). Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013 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.
