$cb->($_[0], $1, $2);
      1
   }
};

# compatibility with older API
sub push_read_line {
   my $self = shift;
   $self->push_read (line => @_);
}

sub unshift_read_line {
   my $self = shift;
   $self->unshift_read (line => @_);
}

=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)

Makes a regex match against the regex object C<$accept> and returns
everything up to and including the match.

Example: read a single line terminated by '\n'.

   $handle->push_read (regex => qr<\n>, sub { ... });

If C<$reject> is given and not undef, then it determines when the data is
to be rejected: it is matched against the data when the C<$accept> regex
does not match and generates an C<EBADMSG> error when it matches. This is
useful to quickly reject wrong data (to avoid waiting for a timeout or a
receive buffer overflow).

Example: expect a single decimal number followed by whitespace, reject
anything else (not the use of an anchor).

   $handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });

If C<$skip> is given and not C<undef>, then it will be matched against
the receive buffer when neither C<$accept> nor C<$reject> match,
and everything preceding and including the match will be accepted
unconditionally. This is useful to skip large amounts of data that you
know cannot be matched, so that the C<$accept> or C<$reject> regex do not
have to start matching from the beginning. This is purely an optimisation
and is usually worth only when you expect more than a few kilobytes.

Example: expect a http header, which ends at C<\015\012\015\012>. Since we
expect the header to be very large (it isn't in practise, but...), we use
a skip regex to skip initial portions. The skip regex is tricky in that
it only accepts something not ending in either \015 or \012, as these are
required for the accept regex.

   $handle->push_read (regex =>
      qr<\015\012\015\012>,
      undef, # no reject
      qr<^.*[^\015\012]>,
      sub { ... });

=cut

register_read_type regex => sub {
   my ($self, $cb, $accept, $reject, $skip) = @_;

   my $data;
   my $rbuf = \$self->{rbuf};

   sub {
      # accept
      if ($$rbuf =~ $accept) {
         $data .= substr $$rbuf, 0, $+[0], "";
         $cb->($self, $data);
         return 1;
      }
      
      # reject
      if ($reject && $$rbuf =~ $reject) {
         $self->_error (&Errno::EBADMSG);
      }

      # skip
      if ($skip && $$rbuf =~ $skip) {
         $data .= substr $$rbuf, 0, $+[0], "";
      }

      ()
   }
};

=item netstring => $cb->($handle, $string)

A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).

Throws an error with C<$!> set to EBADMSG on format violations.

=cut

register_read_type netstring => sub {
   my ($self, $cb) = @_;

   sub {
      unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {