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@@ -0,0 +1,66 @@ +Description + +Lzip is a lossless data compressor based on the LZMA algorithm, with +very safe integrity checking and a user interface similar to the one of +gzip or bzip2. Lzip decompresses almost as fast as gzip and compresses +better than bzip2, which makes it well suited for software distribution +and data archiving. + +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 multimember 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 will automatically use the smallest possible dictionary size for +each member without exceeding the given limit. It is important to +appreciate that the decompression memory requirement is affected at +compression time by the choice of dictionary size limit. + +As a self-check for your protection, lzip stores in the member trailer +the 32-bit CRC of the original data and the size of the original data, +to make sure 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, less than one +chance in 4000 million for each member processed. 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. + +Lzip implements a simplified version of the LZMA (Lempel-Ziv-Markov +chain-Algorithm) algorithm. The original LZMA algorithm was designed by +Igor Pavlov. + +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. + + +Copyright (C) 2008, 2009 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 this +file. |