Compress::Raw::Bzip2 - Low-Level Interface to bzip2 compression library
use Compress::Raw::Bzip2 ;
my ($bz, $status) = new Compress::Raw::Bzip2 [OPTS]
or die "Cannot create bzip2 object: $bzerno\n";
$status = $bz->bzdeflate($input, $output);
$status = $bz->bzflush($output);
$status = $bz->bzclose($output);
my ($bz, $status) = new Compress::Raw::Bunzip2 [OPTS]
or die "Cannot create bunzip2 object: $bzerno\n";
$status = $bz->bzinflate($input, $output);
my $version = Compress::Raw::Bzip2::bzlibversion();Compress::Raw::Bzip2 provides an interface to the in-memory compression/uncompression functions from the bzip2 compression library.
Although the primary purpose for the existence of Compress::Raw::Bzip2 is for use by the IO::Compress::Bzip2 and IO::Compress::Bunzip2 modules, it can be used on its own for simple compression/uncompression tasks.
Creates a new compression object.
If successful, it will return the initialised compression object, $z and a $status of BZ_OK in a list context. In scalar context it returns the deflation object, $z, only.
If not successful, the returned compression object, $z, will be undef and $status will hold the a bzip2 error code.
Below is a list of the valid options:
Controls whether the compressed data is appended to the output buffer in the bzdeflate, bzflush and bzclose methods.
Defaults to 1.
To quote the bzip2 documentation
blockSize100k specifies the block size to be used for compression. It
should be a value between 1 and 9 inclusive, and the actual block size
used is 100000 x this figure. 9 gives the best compression but takes
most memory.Defaults to 1.
To quote the bzip2 documentation
This parameter controls how the compression phase behaves when
presented with worst case, highly repetitive, input data. If
compression runs into difficulties caused by repetitive data, the
library switches from the standard sorting algorithm to a fallback
algorithm. The fallback is slower than the standard algorithm by
perhaps a factor of three, but always behaves reasonably, no matter how
bad the input.
Lower values of workFactor reduce the amount of effort the standard
algorithm will expend before resorting to the fallback. You should set
this parameter carefully; too low, and many inputs will be handled by
the fallback algorithm and so compress rather slowly, too high, and
your average-to-worst case compression times can become very large. The
default value of 30 gives reasonable behaviour over a wide range of
circumstances.
Allowable values range from 0 to 250 inclusive. 0 is a special case,
equivalent to using the default value of 30.Defaults to 0.
Reads the contents of $input, compresses it and writes the compressed data to $output.
Returns BZ_RUN_OK on success and a bzip2 error code on failure.
If appendOutput is enabled in the constructor for the bzip2 object, the compressed data will be appended to $output. If not enabled, $output will be truncated before the compressed data is written to it.