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authorDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 15:34:49 +0000
committerDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 15:34:49 +0000
commit7421b48c7505faa0415b255b34538c44093ec1fa (patch)
treee12893016048b34824da8a78e7f448946e42e2ab /doc/plzip.texinfo
parentAdding debian version 1.0~rc1-3. (diff)
downloadplzip-7421b48c7505faa0415b255b34538c44093ec1fa.tar.xz
plzip-7421b48c7505faa0415b255b34538c44093ec1fa.zip
Merging upstream version 1.0.
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to 'doc/plzip.texinfo')
-rw-r--r--doc/plzip.texinfo63
1 files changed, 35 insertions, 28 deletions
diff --git a/doc/plzip.texinfo b/doc/plzip.texinfo
index 5e62234..b832884 100644
--- a/doc/plzip.texinfo
+++ b/doc/plzip.texinfo
@@ -6,8 +6,8 @@
@finalout
@c %**end of header
-@set UPDATED 8 March 2013
-@set VERSION 1.0-rc1
+@set UPDATED 29 May 2013
+@set VERSION 1.0
@dircategory Data Compression
@direntry
@@ -35,12 +35,12 @@
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
-* Problems:: Reporting bugs
-* Concept Index:: Index of concepts
+* 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
+* Problems:: Reporting bugs
+* Concept Index:: Index of concepts
@end menu
@sp 1
@@ -57,13 +57,18 @@ to copy, distribute and modify it.
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 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 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, plzip can use hundreds of processors.
+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
@@ -92,15 +97,16 @@ file from that of the compressed file as follows:
@end multitable
As a self-check for your protection, plzip 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 plzip (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.
+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).
@@ -109,11 +115,6 @@ Therefore, if the data you are going to compress is important, give the
you verify the compressed file with a command like
@w{@samp{plzip -cd file.lz | cmp file -}}.
-Return values: 0 for a normal exit, 1 for environmental problems (file
-not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or
-invalid input file, 3 for an internal consistency error (eg, bug) which
-caused plzip to panic.
-
@node Program Design
@chapter Program Design
@@ -289,6 +290,12 @@ Table of SI and binary prefixes (unit multipliers):
@item Y @tab yottabyte (10^24) @tab | @tab Yi @tab yobibyte (2^80)
@end multitable
+@sp 1
+Exit status: 0 for a normal exit, 1 for environmental problems (file not
+found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or
+invalid input file, 3 for an internal consistency error (eg, bug) which
+caused plzip to panic.
+
@node File Format
@chapter File Format
@@ -349,7 +356,7 @@ Valid values for dictionary size range from 4KiB to 512MiB.
@item Lzma stream
The lzma stream, finished by an end of stream marker. Uses default values
-for encoder properties.
+for encoder properties. See the lzip manual for a full description.
@item CRC32 (4 bytes)
CRC of the uncompressed original data.
@@ -359,8 +366,8 @@ Size of the uncompressed original data.
@item Member size (8 bytes)
Total size of the member, including header and trailer. This field acts
-as a distributed index, and facilitates safe recovery of undamaged
-members from multi-member files.
+as a distributed index, allows the verification of stream integrity, and
+facilitates safe recovery of undamaged members from multi-member files.
@end table