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Adding upstream version 1.1~pre1.

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Signed-off-by: Daniel Baumann <daniel@debian.org>
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Daniel Baumann 2025-02-24 04:01:20 +01:00
parent 4bce01c02a
commit e7c68f81ff
Signed by: daniel
GPG key ID: FBB4F0E80A80222F
17 changed files with 356 additions and 277 deletions

80
doc/plzip.texinfo
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@ -6,8 +6,8 @@
@finalout
@c %**end of header
@set UPDATED 29 May 2013
@set VERSION 1.0
@set UPDATED 20 July 2013
@set VERSION 1.1-pre1
@dircategory Data Compression
@direntry
@ -36,11 +36,11 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}).
@menu
* Introduction:: Purpose and features of plzip
* Program Design:: Internal structure of plzip
* Invoking Plzip:: Command line interface
* File Format:: Detailed format of the compressed file
* Program design:: Internal structure of plzip
* Invoking plzip:: Command line interface
* File format:: Detailed format of the compressed file
* Problems:: Reporting bugs
* Concept Index:: Index of concepts
* Concept index:: Index of concepts
@end menu
@sp 1
@ -55,21 +55,40 @@ to copy, distribute and modify it.
@cindex introduction
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.
based on the lzlib compression library, with a user interface similar to
the one of lzip, bzip2 or gzip.
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 can compress/decompress large files on multiprocessor machines
much faster than lzip, at the cost of a slightly reduced compression
ratio. On files large enough (several GB), plzip can use hundreds of
processors. On files of only a few MB it is better to use lzip.
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 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.
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 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.
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.
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,
@ -96,18 +115,6 @@ file from that of the compressed file as follows:
@item anyothername @tab becomes @tab anyothername.out
@end multitable
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.
WARNING! Even if plzip is bug-free, other causes may result in a corrupt
compressed file (bugs in the system libraries, memory errors, etc).
Therefore, if the data you are going to compress is important, give the
@ -116,8 +123,8 @@ you verify the compressed file with a command like
@w{@samp{plzip -cd file.lz | cmp file -}}.
@node Program Design
@chapter Program Design
@node Program design
@chapter Program design
@cindex program design
For each input file, a splitter thread and several worker threads are
@ -138,8 +145,8 @@ large files with many members is only limited by the number of
processors available and by I/O speed.
@node Invoking Plzip
@chapter Invoking Plzip
@node Invoking plzip
@chapter Invoking plzip
@cindex invoking
@cindex options
@cindex usage
@ -237,7 +244,8 @@ Use it together with @samp{-v} to see information about the file.
@item -v
@itemx --verbose
Verbose mode.@*
When compressing, show the compression ratio for each file processed.@*
When compressing, show the compression ratio for each file processed. A
second -v shows the progress of compression.@*
When decompressing or testing, further -v's (up to 4) increase the
verbosity level, showing status, compression ratio, decompressed size,
and compressed size.
@ -297,8 +305,8 @@ invalid input file, 3 for an internal consistency error (eg, bug) which
caused plzip to panic.
@node File Format
@chapter File Format
@node File format
@chapter File format
@cindex file format
Perfection is reached, not when there is no longer anything to add, but
@ -387,8 +395,8 @@ If you find a bug in plzip, please send electronic mail to
find by running @w{@samp{plzip --version}}.
@node Concept Index
@unnumbered Concept Index
@node Concept index
@unnumbered Concept index
@printindex cp