Description

Lzip is a lossless data compressor based on the LZMA (Lempel-Ziv-Markov
chain-Algorithm) algorithm designed by Igor Pavlov. The high compression
of LZMA comes from combining two basic, well-proven compression ideas:
sliding dictionaries (i.e. LZ77/78), and markov models (i.e. 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.

Lzip is not a replacement for gzip or bzip2, but a complement; which one
is best to use depends on user's needs. Gzip is the fastest and most
widely used. Bzip2 compresses better than gzip but is slower, both
compressing and decompressing. Lzip decompresses almost as fast as gzip
and compresses better than bzip2, but requires more memory and time
during compression. These features make lzip well suited for software
distribution and data archival.

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.

Lzip has a user interface similar to the one of gzip or bzip2. It
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.

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.


Copyright (C) 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
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