    Description

    Plzip is a massively parallel (multi-threaded) implementation of lzip, fully
    compatible with lzip 1.4 or newer. Plzip uses the compression library lzlib.

    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, chosen to maximize safety and
    interoperability. 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.

    Plzip can compress/decompress large files on multiprocessor machines much
    faster than lzip, at the cost of a slightly reduced compression ratio (0.4
    to 2 percent larger compressed files). Note that the number of usable
    threads is limited by file size; on files larger than a few GB plzip can use
    hundreds of processors, but on files of only a few MB plzip is no faster
    than lzip.

    For creation and manipulation of compressed tar archives tarlz can be more
    efficient than using tar and plzip because tarlz is able to keep the
    alignment between tar members and lzip members.

    When compressing, plzip divides the input file into chunks and compresses as
    many chunks simultaneously as worker threads are chosen, creating a
    multimember compressed file.

    When decompressing, plzip decompresses as many members simultaneously as
    worker threads are chosen. Files that were compressed with lzip will not
    be decompressed faster than using lzip (unless the option '-b' was used)
    because lzip usually produces single-member files, which can't be
    decompressed in parallel.

    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.

    Plzip uses the same well-defined exit status values used by lzip, which
    makes it safer than compressors returning ambiguous warning values (like
    gzip) when it is used as a back end for other programs like tar or zutils.

    Plzip will automatically use for each file the largest dictionary size that
    does not exceed neither the file size nor the limit given. Keep in mind that
    the decompression memory requirement is affected at compression time by the
    choice of dictionary size limit.

    When compressing, plzip replaces every file given in the command line
    with a compressed version of itself, with the name "original_name.lz".
    When decompressing, plzip attempts to guess the name for the decompressed
    file from that of the compressed file as follows:

    filename.lz    becomes   filename
    filename.tlz   becomes   filename.tar
    anyothername   becomes   anyothername.out

    (De)compressing a file is much like copying or moving it; therefore plzip
    preserves the access and modification dates, permissions, and, when
    possible, ownership of the file just as 'cp -p' does. (If the user ID or
    the group ID can't be duplicated, the file permission bits S_ISUID and
    S_ISGID are cleared).

    Plzip is able to read from some types of non-regular files if either the
    option '-c' or the option '-o' is specified.

    If no file names are specified, plzip compresses (or decompresses) from
    standard input to standard output. Plzip will refuse to read compressed data
    from a terminal or write compressed data to a terminal, as this would be
    entirely incomprehensible and might leave the terminal in an abnormal state.

    Plzip will correctly decompress a file which is the concatenation of two or
    more compressed files. The result is the concatenation of the corresponding
    decompressed files. Integrity testing of concatenated compressed files is
    also supported.

    LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never have
    been compressed. Decompressed is used to refer to data which have undergone
    the process of decompression.

    Copyright (C) 2009-2021 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.