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|
#========================================================================
#
# Badger::Codec::Chain
#
# DESCRIPTION
# Codec for encoding/decoding data via a chain of other codecs.
#
# AUTHOR
# Andy Wardley <abw@wardley.org>
#
#========================================================================
package Badger::Codec::Chain;
use Badger::Codecs;
use Badger::Class
version => 0.01,
debug => 0,
base => 'Badger::Codec',
constants => 'ARRAY',
constant => {
CODECS => 'Badger::Codecs',
CHAIN => __PACKAGE__,
CHAINED => qr/\s*\+\s*/,
},
exports => {
any => 'CHAIN CHAINED'
};
sub new {
my $class = shift;
my $chain = @_ == 1 ? shift : [ @_ ];
# single argument can be a text string or array ref
# each argument in an array can be a codec ref or codec name/chain
# all codec names must be upgraded to codec objects
$chain = [ $chain ] unless ref $chain eq ARRAY;
$chain = [ map { ref $_ ? $_ : split(CHAINED, $_) } @$chain ];
$chain = [ map { ref $_ ? $_ : CODECS->codec($_) } @$chain ];
$class->debug("chaining codecs: ", join(' + ', @$chain), "\n") if $DEBUG;
bless {
chain => $chain,
}, $class;
}
sub encode {
my $self = shift;
my $data = shift;
foreach my $codec (@{ $self->{ chain } }) {
$data = $codec->encode($data);
}
return $data;
}
sub decode {
my $self = shift;
my $data = shift;
foreach my $codec (reverse @{ $self->{ chain } }) {
$data = $codec->decode($data);
}
return $data;
}
sub encoder {
my $self = shift;
return $self->coder(
map { $_->encoder }
@{ $self->{ chain } }
);
}
sub decoder {
my $self = shift;
return $self->coder(
reverse map { $_->decoder }
@{ $self->{ chain } }
);
}
sub coder {
my $self = shift;
my $coders = @_ && ref $_[0] eq ARRAY ? shift : [@_];
return sub {
my $data = shift;
foreach my $coder (@$coders) {
$data = $coder->($data);
}
return $data;
}
}
1;
__END__
=head1 NAME
Badger::Codec::Chain - encode/decode data using multiple codecs
=head1 SYNOPSIS
use Badger::Codec::Chain;
# compact form
my $codec = Badger::Codec::Chain->new('storable+base64');
# explicit form
my $codec = Badger::Codec::Chain->new('storable', 'base64');
# encode/decode data using codec chain
my $enc = $codec->encode({ pi => 3.14, e => 2.718 });
my $dec = $codec->decode($encoded);
=head1 DESCRIPTION
This module implements a subclass of L<Badger::Codec> which chains
together any number of other codec modules.
=head1 METHODS
=head2 new(@codecs)
Constructor method to create a new codec chain. The codecs can be
specified by name or as references to L<Badger::Codec> objects.
# by name
my $codec = Badger::Codec::Chain->new('storable', 'base64');
# by object reference
my $codec = Badger::Codec::Chain->new(
Badger::Codec->codec('storable'),
Badger::Codec->codec('base64'),
);
You can also use the compact form where multiple codec names are
separated by C<+>.
# compact form
my $codec = Badger::Codec::Chain->new('storable+base64');
=head2 encode($data)
Encodes the data referenced by the first argument using all the
codecs in the chain.
$encoded = $codec->encode($data);
=head2 decode($html)
Decodes the encoded data passed as the first argument using all
the codecs in the chain B<in reverse order>.
$decoded = $codec->decode($encoded);
=head2 encoder()
Returns a reference to a subroutine which performs the encoding operation.
=head2 decoder()
Returns a reference to a subroutine which performs the decoding operation.
=head1 INTERNAL METHODS
=head2 coder(@coders)
Internal method to construct an encoder or decoder subroutine for a codec
chain.
=head1 AUTHOR
Andy Wardley L<http://wardley.org/>
=head1 COPYRIGHT
Copyright (C) 2005-2009 Andy Wardley. All rights reserved.
=head1 SEE ALSO
L<Badger::Codecs>, L<Badger::Codec>.
=cut
# Local Variables:
# mode: Perl
# perl-indent-level: 4
# indent-tabs-mode: nil
# End:
#
# vim: expandtab shiftwidth=4:
|
