Dpkg::Compression(3perl) libdpkg-perl Dpkg::Compression(3perl)
NAME
Dpkg::Compression - simple database of available compression methods
DESCRIPTION
This modules provides a few public functions and a public regex to
interact with the set of supported compression methods.
FUNCTIONS
@list = compression_get_list()
Returns a list of supported compression methods (sorted
alphabetically).
compression_is_supported($comp)
Returns a boolean indicating whether the give compression method is
known and supported.
compression_get_property($comp, $property)
Returns the requested property of the compression method. Returns
undef if either the property or the compression method doesn't
exist. Valid properties currently include "file_ext" for the file
extension, "default_level" for the default compression level,
"comp_prog" for the name of the compression program and
"decomp_prog" for the name of the decompression program.
This function is deprecated, please switch to one of the new
specialized getters instead.
compression_guess_from_filename($filename)
Returns the compression method that is likely used on the indicated
filename based on its file extension.
$regex = compression_get_file_extension_regex()
Returns a regex that matches a file extension of a file compressed
with one of the supported compression methods.
$ext = compression_get_file_extension($comp)
Return the file extension for the compressor $comp.
$comp = compression_get_default()
Return the default compression method. It is "xz" unless
compression_set_default() has been used to change it.
compression_set_default($comp)
Change the default compression method. Errors out if the given
compression method is not supported.
$level = compression_get_default_level()
Return the global default compression level used when compressing
data if it has been set, otherwise the default level for the default
compressor.
It's "9" for "gzip" and "bzip2", "6" for "xz" and "lzma", unless
compression_set_default_level() has been used to change it.
compression_set_default_level($level)
Change the global default compression level. Passing undef as the
level will reset it to the global default compressor specific
default, otherwise errors out if the level is not valid (see
compression_is_valid_level()).
$level = compression_get_level($comp)
Return the compression level used when compressing data with a
specific compressor. The value returned is the specific compression
level if it has been set, otherwise the global default compression
level if it has been set, falling back to the specific default
compression level.
compression_set_level($comp, $level)
Change the compression level for a specific compressor. Passing
undef as the level will reset it to the specific default compressor
level, otherwise errors out if the level is not valid (see
compression_is_valid_level()).
compression_is_valid_level($level)
Returns a boolean indicating whether $level is a valid compression
level (it must be either a number between 1 and 9 or "fast" or
"best")
$threads = compression_get_threads()
Return the number of threads to use for compression and
decompression.
compression_set_threads($threads)
Change the threads to use for compression and decompression. Passing
"undef" or 0 requests to use automatic mode, based on the current
CPU cores on the system.
@exec = compression_get_cmdline_compress($comp)
Returns a list ready to be passed to exec(), its first element is
the program name for compression and the following elements are
parameters for the program.
When executed the program will act as a filter between its standard
input and its standard output.
@exec = compression_get_cmdline_decompress($comp)
Returns a list ready to be passed to exec(), its first element is
the program name for decompression and the following elements are
parameters for the program.
When executed the program will act as a filter between its standard
input and its standard output.
CHANGES
Version 2.01 (dpkg 1.21.14)
New functions: compression_get_file_extension(),
compression_get_level(), compression_set_level(),
compression_get_cmdline_compress(),
compression_get_cmdline_decompress(), compression_get_threads() and
compression_set_threads().
Deprecated functions: compression_get_property().
Version 2.00 (dpkg 1.20.0)
Hide variables: $default_compression, $default_compression_level and
$compression_re_file_ext.
Version 1.02 (dpkg 1.17.2)
New function: compression_get_file_extension_regex()
Deprecated variables: $default_compression, $default_compression_level
and $compression_re_file_ext
Version 1.01 (dpkg 1.16.1)
Default compression level is not global any more, it is per compressor
type.
Version 1.00 (dpkg 1.15.6)
Mark the module as public.
1.22.21 2025-06-30 Dpkg::Compression(3perl)
Generated by dwww version 1.16 on Tue Dec 16 05:39:32 CET 2025.