sub new {
    my ($class, @args) = @_;
    my ($encoding) = @args;
    my ($concrete_name, $concrete_path);

    ### Coerce the type to be legit:
    $encoding = lc($encoding || '');

    ### Get the class:
    ($concrete_name = $DecoderFor{$encoding}) or return undef;
    ($concrete_path = $concrete_name.'.pm') =~ s{::}{/}g;

    ### Create the new object (if we can):
    my $self = { MD_Encoding => lc($encoding) };
    require $concrete_path;
    bless $self, $concrete_name;
    $self->init(@args);
}

### The stream decoders:
%DecoderFor = (

     ### Standard...
    '7bit'       => 'MIME::Decoder::NBit',
    '8bit'       => 'MIME::Decoder::NBit',
    'base64'     => 'MIME::Decoder::Base64',
    'binary'     => 'MIME::Decoder::Binary',
    'none'       => 'MIME::Decoder::Binary',
    'quoted-printable' => 'MIME::Decoder::QuotedPrint',
    # snip
);

sub init {
    $_[0];
}