#!perl

use Archive::Tar;

my $t = Archive::Tar->new();
$t->read($ARGV[0]) or die "Must specify valid input file - $!\n";

# this regex can be changed to fit the platform specific 
# illegal characters to watch for.
my $BAD_CHARACTERS = '[?]';

my %sig;
my $i;
foreach my $h ($t->data()) {

        # typeflag 5 is a folder.
        if ($h->{typeflag} == 5) {
                my @folders = split '/', $h->{name};
                my @newf = ();
                foreach (@folders) {
                    my $new;
                    if (/$BAD_CHARACTERS/) {
                        if ($sig{$_}) {
                            # this happens if we step on a previously
                            # recovered folder.
                            $new = $sig{$_};
                        } else {
                            $new = "_recovered_folder" . ++$i;
                            $sig{$_} = $new;
                        }
                    } else {
                        $new = $_;
                    }
                    push @newf, $new;
                }
                $sig{$h->{name}} = join '/', @newf;
                foreach (@newf) {
                    mkdir $_; # actually there would be a lot of errors here
                              # had it been possible,
                              # an mkdir -p $_ would have been better.
                    chdir $_;
                }
                $out = '../' x @newf;
                chdir $out or die "I must have overdone myself. $!\n";
        } 
        else {
                my $name = $h->{name};
                my ($nm) = (split '/', $name)[-1];
                $new = $nm;
                
                if ($nm =~ /$BAD_CHARACTERS/) {
                        my ($ext) = $nm =~ /\.(.*)$/; # pickup extension.
                        $new = "_recovered_file" . ++$i . ".$ext";
                }

                my $folder = $name;
                $folder =~ s/\Q$nm\E//;
                $folder = $sig{$folder};
                my @times = split '/', $folder;

                chdir $folder or die "where did that '$folder' go? $!\n";

                open OUT, ">$new" or die "$!\n";
                binmode (OUT);
                print OUT $h->{data};
                close OUT;

                $myout = '../' x @times;
                chdir $myout or die "again? $!\n";
        }
}