MDV::Packdrakeng(3) User Contributed Perl Documentation MDV::Packdrakeng(3)NAMEMDV::Packdrakeng - Simple Archive Extractor/Builder
SYNOPSIS
use MDV::Packdrakeng;
# creating an archive
$pack = MDV::Packdrakeng->new(archive => "myarchive.cz");
# Adding a few files
$pack->add("/path/", "file1", "file2");
# Adding an unamed file
open($handle, "file");
$pack->add_virtual("filename", $handle);
close($handle);
$pack = undef;
# extracting an archive
$pack = MDV::Packdrakeng->open(archive => "myarchive.cz");
# listing files
$pack->list();
# extracting few files
$pack->extract("/path/", "file1", "file2");
# extracting data into a file handle
open($handle, "file");
$pack->extract_virtual($handle, "filename");
close($handle);
DESCRIPTION
"MDV::Packdrakeng" is a simple indexed archive builder and extractor
using standard compression methods.
IMPLEMENTATION
Compressed data are stored by block. For example,
UncompresseddatA1UncompresseddatA2 UncompresseddatA3UncompresseddatA4
|--- size 1 ---||--- size 2 ---| |--- size 3 ---||--- size 4 ---|
|<-offset1 |<-offset2 |<-offset3 |<-offset4
gives:
CompresseD1CompresseD2 CompresseD3CompresseD4
|--- c. size 1, 2 ---| |--- c. size 3, 4 ---|
|<-c. offset 1, 2 |<-c. offset 3, 4
A new block is started when its size exceeds the "block_size" value.
Compressed data are followed by the table of contents (toc), that is, a
simple list of packed files. Each file name is terminated by the "\n"
character:
dir1
dir2
...
dirN
symlink1
point_file1
symlink2
point_file2
...
...
symlinkN
point_fileN
file1
file2
...
fileN
The file sizes follows, 4 values are stored for each file: offset into
archive of compressed block, size of compressed block, offset into
block of the file and the file's size.
Finally the archive contains a 64-byte trailer, about the toc and the
archive itself:
'cz[0', strings 4 bytes
number of directory, 4 bytes
number of symlinks, 4 bytes
number of files, 4 bytes
the toc size, 4 bytes
the uncompression command, string of 40 bytes length
'0]cz', string 4 bytes
FUNCTIONS
new(%options)
Creates a new archive. Options:
archive
The file name of the archive. If the file doesn't exist, it will
be created, else it will be owerwritten. See "open".
compress
The application to use to compress, if unspecified, gzip is used.
uncompress
The application used to extract data from archive. This option is
useless if you're opening an existing archive (unless you want to
force it). If unset, this value is based on compress command
followed by '-d' argument.
extern
If you're using gzip, by default MDV::Packdrakeng will use perl-
zlib to save system ressources. This option forces
MDV::Packdrakeng to use the external gzip command. This has no
meaning with other compress programs as internal functions are
not implemented yet.
comp_level
The compression level passed as an argument to the compression
program. By default, this is set to 6.
block_size
The limit size after which we start a new compressed block. The
default value is 400KB. Set it to 0 to be sure a new block will
be started for each packed files, and -1 to never start a new
block. Be aware that a big block size will slow down the file
extraction.
quiet
Do not output anything, shut up.
debug
Print debug messages.
open(%options)
Opens an existing archive for extracting or adding files.
The uncompression command is found into the archive, and the
compression command is deduced from it.
If you add files, a new compressed block will be started even if the
last block is smaller than the value of the "block_size" option. If
some compression options can't be found in the archive, the new
preference will be applied.
Options are the same than for the "new()" function.
MDV::Packdrakeng->add_virtual($type, $filename, $data)
Adds a file into archive according passed information. $type gives
the type of the file:
- 'd', the file will be a directory, store as '$filename'. $data is not used.
- 'l', the file will be a symlink named $filename, pointing to the file whose path
is given by the string $data.
- 'f', the file is a normal file, $filename will be its name, $data is either
an handle to open file, data will be read from current position to the
end of file, either a string to push as the content of the file.
MDV::Packdrakeng->add($prefix, @files)
Adds @files into archive located into $prefix. Only directory, files
and symlink will be added. For each file, the path should be relative
to $prefix and is stored as is.
MDV::Packdrakeng->extract_virtual(*HANDLE, $filename)
Extracts $filename data from archive into the *HANDLE. $filename
should be a normal file.
MDV::Packdrakeng->extract($destdir, @files)
Extracts @files from the archive into $destdir prefix.
MDV::Packdrakeng->getcontent()
Returns three arrayrefs describing files files into archive,
respectively directory list, files list and symlink list.
MDV::Packdrakeng->infofile($file)
Returns type and information about a given file into the archive;
that is:
- 'f' and the the size of the file for a plain file
- 'l' and the linked file for a symlink
- 'd' and undef for a directory
- undef if the file can't be found into archive.
MDV::Packdrakeng->infofile($handle)
Print to $handle (STDOUT if not specified) the content of the
archive.
MDV::Packdrakeng->dumptoc($handle)
Print to $handle (STDOUT if not specified) the table of content of
the archive.
CHANGELOG
1.10
use an oo code
add_virtual() now accept a string as file content
AUTHOR
Olivier Thauvin <nanardon@mandriva.org>, Rafael Garcia-Suarez
<rgarciasuarez@mandriva.com>
Copyright (c) 2005 Mandriva
This module is a from scratch-rewrite of the original "packdrake"
utility. Its format is fully compatible with the old packdrake.
LICENSE
This program is free software; you can redistribute it and/or modify it
under the terms of GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
If you do not have a copy of the GNU General Public License write to
the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
USA.
perl v5.16.3 2012-01-24 MDV::Packdrakeng(3)
