Description

Plzip is a massively parallel (multi-threaded), lossless data compressor
based on the lzlib compression library, with very safe integrity
checking and a user interface similar to the one of bzip2, gzip or lzip.

Plzip is intended for faster compression/decompression of big files on
multiprocessor machines, which makes it specially well suited for
distribution of big software files and large scale data archiving. On
files big enough (several GB), plzip can use hundreds of processors.

Plzip uses the lzip file format; the files produced by plzip are fully
compatible with lzip-1.4 or newer, and can be rescued with lziprecover.

Plzip uses the same well-defined exit status values used by lzip and
bzip2, which makes it safer when used in pipes or scripts than
compressors returning ambiguous warning values, like gzip.

Plzip 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. Plzip is able to read from some
types of non regular files if the "--stdout" option is specified.

If no file names are specified, plzip compresses (or decompresses) from
standard input to standard output. In this case, plzip will decline to
write compressed output to a terminal, as this would be entirely
incomprehensible and therefore pointless.

Plzip 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, plzip stores in the member trailer
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 very safe 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 plzip (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.


Copyright (C) 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.
