Mini Shell

package Encode::JP::JIS7;
use strict;
use warnings;
our $VERSION = do { my @r = ( q$Revision: 2.8 $ =~ /\d+/g ); sprintf "%d." . "%02d" x $#r, @r };

use Encode qw(:fallbacks);

for my $name ( '7bit-jis', 'iso-2022-jp', 'iso-2022-jp-1' ) {
    my $h2z     = ( $name eq '7bit-jis' )    ? 0 : 1;
    my $jis0212 = ( $name eq 'iso-2022-jp' ) ? 0 : 1;

    my $obj = bless {
        Name    => $name,
        h2z     => $h2z,
        jis0212 => $jis0212,
    } => __PACKAGE__;
    Encode::define_encoding($obj, $name);
}

use parent qw(Encode::Encoding);

# we override this to 1 so PerlIO works
sub needs_lines { 1 }

use Encode::CJKConstants qw(:all);

#
# decode is identical for all 2022 variants
#

sub decode($$;$) {
    my ( $obj, $str, $chk ) = @_;
    return undef unless defined $str;
    my $residue = '';
    if ($chk) {
        $str =~ s/([^\x00-\x7f].*)$//so and $residue = $1;
    }
    $residue .= jis_euc( \$str );
    $_[1] = $residue if $chk;
    return Encode::decode( 'euc-jp', $str, FB_PERLQQ );
}

#
# encode is different
#

sub encode($$;$) {
    require Encode::JP::H2Z;
    my ( $obj, $utf8, $chk ) = @_;
    return undef unless defined $utf8;

    # empty the input string in the stack so perlio is ok
    $_[1] = '' if $chk;
    my ( $h2z, $jis0212 ) = @$obj{qw(h2z jis0212)};
    my $octet = Encode::encode( 'euc-jp', $utf8, $chk || 0 );
    $h2z and &Encode::JP::H2Z::h2z( \$octet );
    euc_jis( \$octet, $jis0212 );
    return $octet;
}

#
# cat_decode
#
my $re_scan_jis_g = qr{
   \G ( ($RE{JIS_0212}) |  $RE{JIS_0208}  |
        ($RE{ISO_ASC})  | ($RE{JIS_KANA}) | )
      ([^\e]*)
}x;

sub cat_decode {    # ($obj, $dst, $src, $pos, $trm, $chk)
    my ( $obj, undef, undef, $pos, $trm ) = @_;    # currently ignores $chk
    my ( $rdst, $rsrc, $rpos ) = \@_[ 1, 2, 3 ];
    local ${^ENCODING};
    use bytes;
    my $opos = pos($$rsrc);
    pos($$rsrc) = $pos;
    while ( $$rsrc =~ /$re_scan_jis_g/gc ) {
        my ( $esc, $esc_0212, $esc_asc, $esc_kana, $chunk ) =
          ( $1, $2, $3, $4, $5 );

        unless ($chunk) { $esc or last; next; }

        if ( $esc && !$esc_asc ) {
            $chunk =~ tr/\x21-\x7e/\xa1-\xfe/;
            if ($esc_kana) {
                $chunk =~ s/([\xa1-\xdf])/\x8e$1/og;
            }
            elsif ($esc_0212) {
                $chunk =~ s/([\xa1-\xfe][\xa1-\xfe])/\x8f$1/og;
            }
            $chunk = Encode::decode( 'euc-jp', $chunk, 0 );
        }
        elsif ( ( my $npos = index( $chunk, $trm ) ) >= 0 ) {
            $$rdst .= substr( $chunk, 0, $npos + length($trm) );
            $$rpos += length($esc) + $npos + length($trm);
            pos($$rsrc) = $opos;
            return 1;
        }
        $$rdst .= $chunk;
        $$rpos = pos($$rsrc);
    }
    $$rpos = pos($$rsrc);
    pos($$rsrc) = $opos;
    return '';
}

# JIS<->EUC
my $re_scan_jis = qr{
   (?:($RE{JIS_0212})|$RE{JIS_0208}|($RE{ISO_ASC})|($RE{JIS_KANA}))([^\e]*)
}x;

sub jis_euc {
    local ${^ENCODING};
    my $r_str = shift;
    $$r_str =~ s($re_scan_jis)
    {
    my ($esc_0212, $esc_asc, $esc_kana, $chunk) =
       ($1, $2, $3, $4);
    if (!$esc_asc) {
        $chunk =~ tr/\x21-\x7e/\xa1-\xfe/;
        if ($esc_kana) {
        $chunk =~ s/([\xa1-\xdf])/\x8e$1/og;
        }
        elsif ($esc_0212) {
        $chunk =~ s/([\xa1-\xfe][\xa1-\xfe])/\x8f$1/og;
        }
    }
    $chunk;
    }geox;
    my ($residue) = ( $$r_str =~ s/(\e.*)$//so );
    return $residue;
}

sub euc_jis {
    no warnings qw(uninitialized);
    local ${^ENCODING};
    my $r_str   = shift;
    my $jis0212 = shift;
    $$r_str =~ s{
    ((?:$RE{EUC_C})+|(?:$RE{EUC_KANA})+|(?:$RE{EUC_0212})+)
    }{
        my $chunk = $1;
        my $esc =
        ( $chunk =~ tr/\x8E//d ) ? $ESC{KANA} :
            ( $chunk =~ tr/\x8F//d ) ? $ESC{JIS_0212} :
            $ESC{JIS_0208};
        if ($esc eq $ESC{JIS_0212} && !$jis0212){
        # fallback to '?'
        $chunk =~ tr/\xA1-\xFE/\x3F/;
        }else{
        $chunk =~ tr/\xA1-\xFE/\x21-\x7E/;
        }
        $esc . $chunk . $ESC{ASC};
    }geox;
    $$r_str =~ s/\Q$ESC{ASC}\E
        (\Q$ESC{KANA}\E|\Q$ESC{JIS_0212}\E|\Q$ESC{JIS_0208}\E)/$1/gox;
    $$r_str;
}

1;
__END__


=head1 NAME

Encode::JP::JIS7 -- internally used by Encode::JP

=cut