NAME

Compress::LZ4 - Perl interface to the LZ4 (de)compressor

SYNOPSIS

    use Compress::LZ4;

    my $compressed = compress($bytes);
    my $decompressed = decompress($compressed);

DESCRIPTION

The "Compress::LZ4" module provides an interface to the LZ4 (de)compressor.

FUNCTIONS

compress

    $compressed = compress($bytes [, $level])

Compresses the given buffer and returns the resulting bytes. The input buffer can be either a scalar or a scalar reference. The default acceleration level (1) can be changed, with each additional level providing ~3% increase in speed; the compression level will be negatively affected.

compress_hc

    $compressed = compress_hc($bytes [, $level])

A higher-compression, but slower, version of "compress". The default compression level (9) can be changed if an optional value (0-16) is given.

decompress

uncompress

    $bytes = decompress($compressed)

Decompresses the given buffer and returns the resulting bytes. The input buffer can be either a scalar or a scalar reference.

On error (in case of corrupted data) undef is returned.

COMPATIBILITY

This library does not produce output that is compatible with the official frame format. Because LZ4 did not define a container format until long after it was released, many bindings, including this one, prepend the original data size to the compressed data as a little-endian 4-byte integer.

If you are dealing with raw data from an external source that does not format the data this way, you need to use the following functions:

lz4_compress

lz4_compress_hc

Same as "compress"/"compress_hc" but does not add the length header.

lz4_decompress

lz4_uncompress

    $bytes = decompress($compressed, $original_data_size)

Same as "decompress"/"uncompress" but also requires the original data size to be given.

PERFORMANCE

This distribution contains a benchmarking script which compares several modules available on CPAN. These are the results on a MacBook 2.6GHz Core i5 (64-bit) with Perl 5.24.1:

    Compressible data (10 KiB) - compression
    ----------------------------------------
    Compress::LZ4::compress 8   670690/s  6550 MiB/s  1.152%
    Compress::LZ4::compress     649176/s  6340 MiB/s  1.152%
    Compress::Snappy::compress  367492/s  3589 MiB/s  5.332%
    Compress::LZF::compress     127765/s  1248 MiB/s  1.865%
    Compress::LZ4::compress_hc   84620/s   826 MiB/s  1.152%
    Compress::Zlib::compress     15514/s   152 MiB/s  1.201%
    Compress::Bzip2::compress      246/s     2 MiB/s  2.070%

    Compressible data (10 KiB) - decompression
    ------------------------------------------
    Compress::LZF::decompress     1262620/s  12330 MiB/s
    Compress::LZ4::decompress      819200/s   8000 MiB/s
    Compress::Snappy::decompress   619934/s   6054 MiB/s
    Compress::Zlib::uncompress      65163/s    636 MiB/s
    Compress::Bzip2::decompress     12679/s    124 MiB/s

    Uncompressible data (10 KiB) - compression
    ------------------------------------------
    Compress::LZ4::compress 8   2102098/s  20528 MiB/s  109.231%
    Compress::LZ4::compress     1854792/s  18113 MiB/s  109.231%
    Compress::Snappy::compress  1619124/s  15812 MiB/s  104.615%
    Compress::LZF::compress     1349269/s  13176 MiB/s  101.538%
    Compress::LZ4::compress_hc    96376/s    941 MiB/s  109.231%
    Compress::Zlib::compress      66370/s    648 MiB/s  112.308%
    Compress::Bzip2::compress     54098/s    528 MiB/s  201.538%

    Uncompressible data (10 KiB) - decompression
    --------------------------------------------
    Compress::LZF::decompress     5004566/s  48873 MiB/s
    Compress::LZ4::decompress     4915199/s  48000 MiB/s
    Compress::Snappy::decompress  4906438/s  47914 MiB/s
    Compress::Zlib::uncompress     355071/s   3467 MiB/s
    Compress::Bzip2::decompress    175812/s   1717 MiB/s

REQUESTS AND BUGS

Please report any bugs or feature requests to <http://rt.cpan.org/Public/Bug/Report.html?Queue=Compress-LZ4>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Compress::LZ4

You can also look for information at:

GitHub Source Repository
<https://github.com/gray/compress-lz4>
AnnoCPAN: Annotated CPAN documentation
<http://annocpan.org/dist/Compress-LZ4>
CPAN Ratings
<http://cpanratings.perl.org/d/Compress-LZ4>
RT: CPAN's request tracker
<http://rt.cpan.org/Public/Dist/Display.html?Name=Compress-LZ4>
Search CPAN
<http://search.cpan.org/dist/Compress-LZ4/>

COPYRIGHT AND LICENSE

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

AUTHOR

gray, <gray at cpan.org>