NAME

Net::SSH::Perl::Comp - Compression/Decompression base class

SYNOPSIS

use Net::SSH::Perl::Comp;
my $comp = Net::SSH::Perl::Comp->new( $comp_type );
$comp->compress($data);

DESCRIPTION

Net::SSH::Perl::Comp is a base class for compression/decompression classes. Currently the only such class is the Zlib implementation (using Compress::Zlib), which is the class Net::SSH::Perl::Comp::Zlib.

Each compression object generally has its own internal "state"; this state changes when you compress or decompress data. The SSH protocol dictates that you must have two separate objects to compress and decompress data: one for compression, one for decompression. So, for example, you would create two Net::SSH::Perl::Comp objects:

my $in = Net::SSH::Perl::Comp->new('Zlib');
my $inflated = $in->decompress($data);

my $out = Net::SSH::Perl::Comp->new('Zlib');
my $deflated = $out->compress($data);

USAGE

$comp = Net::SSH::Perl::Comp->new( $comp_type [, @args ] )

Constructs a new compression object of compression type $comp_type and returns that object.

If @args are provided, the class's init method is called with those arguments, for any post-creation initialization.

$comp->init($level)

Initializes $comp and sets the compression level to $level. This method will be called automatically from new if you've provided @args to new. So, for example, you could write:

my $comp = Net::SSH::Perl::Comp->new('Zlib', 5);

To create a new Zlib compression object and initialize its compression level to 5.

$comp->compress( $data )

Compresses $data using the underlying compression mechanism; returns the compressed data.

$comp->decompress( $data )

Decompresses $data using the underlying decompression mechanism; returns the decompressed data.

$comp->enable

"Enables" the compression object. This is useful in the context of the key exchange (Kex) classes, which create a new compression object during key negotiation, but don't actually turn it on ("enable" it) until receiving/sending the SSH2_MSG_NEWKEYS message.

Net::SSH::Perl::Comp objects (and subclasses) are disabled by default.

$comp->enabled

Returns the state of the "enabled" flag, ie. whether the compression object is "turned on".

This is used by Net::SSH::Perl::Packet when determining whether data it receives/sends to the server should be decompressed/compressed, respectively.

AUTHOR & COPYRIGHTS

Please see the Net::SSH::Perl manpage for author, copyright, and license information.