# unescape URL-encoded data
sub unescape {
    shift() if ref($_[0]);
    my $todecode = shift;
    return undef unless defined($todecode);
    $todecode =~ tr/+/ /;       # pluses become spaces
    $todecode =~ s/%([0-9a-fA-F]{2})/pack("c",hex($1))/ge;
    return $todecode;
}