Compres...::Bzip2(3pm)

📦
version 5.42.3 · 15 versions
, in alpine 3.24

💅 Compress::Raw::Bzip2 💅

Okay bestie, so this page comes from the Perl Programmers Reference Guide, and its ✨official✨ title up in the corner is Compres...::Bzip2(3pm) — yes, pre-truncated, yes, that's just how it's filed 💀. Anyway. Sit down, we're learning about bzip2 today.

✨ NAME ✨

Compress::Raw::Bzip2 — Low-Level Interface to bzip2 compression library

✨ SYNOPSIS ✨

Ok so here's the vibe, in code, verbatim 🫶:

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();

✨ DESCRIPTION ✨

So "Compress::Raw::Bzip2" gives you an interface to the in-memory compression/uncompression functions from the bzip2 compression library. That's it, that's the whole thing 👑

Now, the primary reason "Compress::Raw::Bzip2" even exists is so that the "IO::Compress::Bzip2" and "IO::Compress::Bunzip2" modules have something to lean on. But fear not — it can totally be used on its own for simple compression/uncompression tasks too. Main character energy, honestly 🌟

🌸 Compression 🌸

($z, $status) = new Compress::Raw::Bzip2 $appendOutput, $blockSize100k,
    $workfactor;

Creates a new compression object ✨

If it works, you get the initialised compression object, $z, plus a $status of "BZ_OK" — in list context. In scalar context it returns the deflation object, $z, only.

If it doesn't work, the returned compression object $z will be undef, and $status will hold a bzip2 error code. Rude but fair 😭

Below is a list of the valid options:

  • $appendOutput — Controls whether the compressed data is appended to the output buffer in the "bzdeflate", "bzflush" and "bzclose" methods. Defaults to 1.
  • $blockSize100k — 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.

  • $workfactor — 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.

🦋 $status = $bz->bzdeflate($input, $output);

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 it's not enabled, $output gets truncated before the compressed data is written to it. No half measures 🎀

🦋 $status = $bz->bzflush($output);

Flushes any pending compressed data to $output.

Returns "BZ_RUN_OK" on success and a "bzip2" error code on failure.

🦋 $status = $bz->bzclose($output);

Terminates the compressed data stream and flushes any pending compressed data to $output.

Returns "BZ_STREAM_END" on success and a "bzip2" error code on failure. That's the finish line, bestie 🏁

🦋 Example

(the docs put this heading here and then, uh, say nothing else. It's giving mystery. Respect 🙈)

🌈 Uncompression 🌈

($z, $status) = new Compress::Raw::Bunzip2 $appendOutput, $consumeInput,
    $small, $verbosity, $limitOutput;

If it works, you get the initialised uncompression object, $z, and a $status of "BZ_OK" in list context. In scalar context it returns the deflation object, $z, only.

If it fails, the returned uncompression object $z will be undef and $status will hold a bzip2 error code.

Below is a list of the valid options:

  • $appendOutput — Controls whether the compressed data is appended to the output buffer in the "bzinflate", "bzflush" and "bzclose" methods. Defaults to 1.
  • $consumeInput
  • $small — To quote the bzip2 documentation:
If small is nonzero, the library will use an alternative decompression algorithm which uses less memory but at the cost of decompressing more slowly (roughly speaking, half the speed, but the maximum memory requirement drops to around 2300k).

Defaults to 0.

(ngl, $consumeInput is listed right there and the docs don't give it its own little paragraph — I'm not gonna invent one for you, we report, we don't speculate 💀)

  • $limitOutput — The "LimitOutput" option changes the behavior of the "$i->bzinflate" method so that the amount of memory used by the output buffer can be limited.

When "LimitOutput" is used the size of the output buffer used will either be the 16k or the amount of memory already allocated to $output, whichever is larger. Predicting the output size available is tricky, so don't rely on getting an exact output buffer size.

When "LimitOutout" is not specified "$i->bzinflate" will use as much memory as it takes to write all the uncompressed data it creates by uncompressing the input buffer.

If "LimitOutput" is enabled, the "ConsumeInput" option will also be enabled.

This option defaults to false.

  • $verbosity — This parameter is ignored. Defaults to 0. (Iconic honestly. Showed up, contributed nothing, left 🌸)

🦋 $status = $z->bzinflate($input, $output);

Uncompresses $input and writes the uncompressed data to $output.

Returns "BZ_OK" if the uncompression was successful, but the end of the compressed data stream has not been reached. Returns "BZ_STREAM_END" on successful uncompression and the end of the compression stream has been reached.

If "consumeInput" is enabled in the constructor for the bunzip2 object, $input will have all compressed data removed from it after uncompression. On a "BZ_OK" return this will mean that $input will be an empty string; when "BZ_STREAM_END" $input will either be an empty string or will contain whatever data immediately followed the compressed data stream. Sneaky leftovers 😼

If "appendOutput" is enabled in the constructor for the bunzip2 object, the uncompressed data will be appended to $output. If not enabled, $output will be truncated before the uncompressed data is written to it.

💜 Misc 💜

🦋 my $version = Compress::Raw::Bzip2::bzlibversion();

Returns the version of the underlying bzip2 library. Cute, quick, no notes ⭐

👑 Constants 👑

The following bzip2 constants are exported by this module:

                BZ_RUN
                BZ_FLUSH
                BZ_FINISH

                BZ_OK
                BZ_RUN_OK
                BZ_FLUSH_OK
                BZ_FINISH_OK
                BZ_STREAM_END
                BZ_SEQUENCE_ERROR
                BZ_PARAM_ERROR
                BZ_MEM_ERROR
                BZ_DATA_ERROR
                BZ_DATA_ERROR_MAGIC
                BZ_IO_ERROR
                BZ_UNEXPECTED_EOF
                BZ_OUTBUFF_FULL
                BZ_CONFIG_ERROR

🫶 SUPPORT 🫶

General feedback/questions/bug reports should be sent to <https://github.com/pmqs/Compress-Raw-Bzip2/issues> (preferred) or <https://rt.cpan.org/Public/Dist/Display.html?Name=Compress-Raw-Bzip2>. Bestie, they prefer the GitHub one, so like… 👀

🌟 SEE ALSO 🌟

Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzip, IO::Uncompress::UnLzip, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Compress::Zstd, IO::Uncompress::UnZstd, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress

IO::Compress::FAQ

File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib

The primary site for the bzip2 program is <https://sourceware.org/bzip2/>.

See the module Compress::Bzip2.

That's a whole friend group right there, fr fr 💖

🎀 AUTHOR 🎀

This module was written by Paul Marquess, "pmqs@cpan.org". Legend behaviour 👑

🧚 MODIFICATION HISTORY 🧚

See the Changes file.

Copyright (c) 2005-2026 Paul Marquess. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

And that's the whole page, bestie — no cap, every last flag and constant accounted for 💅✨

Sign-off vibes: perl v5.42.3, dated 2026-11-03, filed under Compres...::Bzip2(3pm) 🦋💖

📦 where this page comes from