summaryrefslogtreecommitdiffstats
path: root/doc/plzip.texinfo
diff options
context:
space:
mode:
Diffstat (limited to 'doc/plzip.texinfo')
-rw-r--r--doc/plzip.texinfo65
1 files changed, 40 insertions, 25 deletions
diff --git a/doc/plzip.texinfo b/doc/plzip.texinfo
index 517dc11..c83d5a5 100644
--- a/doc/plzip.texinfo
+++ b/doc/plzip.texinfo
@@ -1,12 +1,13 @@
\input texinfo @c -*-texinfo-*-
@c %**start of header
@setfilename plzip.info
+@documentencoding ISO-8859-15
@settitle Plzip Manual
@finalout
@c %**end of header
-@set UPDATED 3 December 2010
-@set VERSION 0.7
+@set UPDATED 17 January 2012
+@set VERSION 0.8
@dircategory Data Compression
@direntry
@@ -43,7 +44,7 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}).
@end menu
@sp 1
-Copyright @copyright{} 2009, 2010 Antonio Diaz Diaz.
+Copyright @copyright{} 2009, 2010, 2011, 2012 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission
to copy, distribute and modify it.
@@ -57,7 +58,7 @@ 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.
+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
@@ -131,8 +132,8 @@ Print an informative help message describing the options and exit.
@itemx --version
Print the version number of plzip on the standard output and exit.
-@item -B
-@itemx --data-size=@var{size}
+@item -B @var{bytes}
+@itemx --data-size=@var{bytes}
Set the input data block size in bytes. The input file will be divided
in chunks of this size before compression is performed. Valid values
range from 8KiB to 1GiB. Default value is two times the dictionary size.
@@ -150,20 +151,25 @@ Decompress.
@item -f
@itemx --force
-Force overwrite of output file.
+Force overwrite of output files.
+
+@item -F
+@itemx --recompress
+Force recompression of files whose name already has the @samp{.lz} or
+@samp{.tlz} suffix.
@item -k
@itemx --keep
Keep (don't delete) input files during compression or decompression.
-@item -m @var{length}
-@itemx --match-length=@var{length}
-Set the match length limit in bytes. Valid values range from 5 to 273.
-Larger values usually give better compression ratios but longer
-compression times.
+@item -m @var{bytes}
+@itemx --match-length=@var{bytes}
+Set the match length limit in bytes. After a match this long is found,
+the search is finished. Valid values range from 5 to 273. Larger values
+usually give better compression ratios but longer compression times.
-@item -n @var{threads}
-@itemx --threads=@var{threads}
+@item -n @var{n}
+@itemx --threads=@var{n}
Set the number of worker threads. Valid values range from 1 to "as many
as your system can support". If this option is not used, plzip tries to
detect the number of processors in the system and use it as default
@@ -180,22 +186,31 @@ and a file named @samp{@var{file}.lz} when compressing.
@itemx --quiet
Quiet operation. Suppress all messages.
-@item -s @var{size}
-@itemx --dictionary-size=@var{size}
+@item -s @var{bytes}
+@itemx --dictionary-size=@var{bytes}
Set the dictionary size limit in bytes. Valid values range from 4KiB to
-512MiB. Note that dictionary sizes are quantized. If the specified size
-does not match one of the valid sizes, it will be rounded upwards.
+512MiB. Plzip will use the smallest possible dictionary size for each
+member without exceeding this limit. Note that dictionary sizes are
+quantized. If the specified size does not match one of the valid sizes,
+it will be rounded upwards by adding up to (@var{bytes} / 16) to it.
+
+For maximum compression you should use a dictionary size limit as large
+as possible, but keep in mind that the decompression memory requirement
+is affected at compression time by the choice of dictionary size limit.
@item -t
@itemx --test
Check integrity of the specified file(s), but don't decompress them.
This really performs a trial decompression and throws away the result.
-Use @samp{-tvv} or @samp{-tvvv} to see information about the file.
+Use it together with @samp{-v} to see information about the file.
@item -v
@itemx --verbose
-Verbose mode. Show the compression ratio for each file processed.
-Further -v's increase the verbosity level.
+Verbose mode.@*
+When compressing, show the compression ratio for each file processed.@*
+When decompressing or testing, further -v's (up to 4) increase the
+verbosity level, showing status, compression ratio, decompressed size,
+and compressed size.
@item -1 .. -9
Set the compression parameters (dictionary size and match length limit)
@@ -297,12 +312,12 @@ All multibyte values are stored in little endian order.
@table @samp
@item ID string
-A four byte string, identifying the member type, with the value "LZIP".
+A four byte string, identifying the lzip format, with the value "LZIP".
@item VN (version number, 1 byte)
Just in case something needs to be modified in the future. Valid values
-are 0 and 1. Version 0 files have only one member and lack @samp{Member
-size}.
+are 0 and 1. Version 0 files are deprecated. They can contain only one
+member and lack the @samp{Member size} field.
@item DS (coded dictionary size, 1 byte)
Bits 4-0 contain the base 2 logarithm of the base dictionary size.@*
@@ -323,7 +338,7 @@ Size of the uncompressed original data.
@item Member size (8 bytes)
Total size of the member, including header and trailer. This facilitates
-safe recovery of undamaged members from multimember files.
+safe recovery of undamaged members from multi-member files.
@end table