sub keep_7bit
{  
   local $_ = shift;
   tr/\x00-\x7F/#/c;
   $_;
}

sub decode_qp
{
    my $res = shift;
    $res =~ s/\r\n/\n/g;            # normalize newlines
    $res =~ s/[ \t]+\n/\n/g;        # rule #3 (trailing space must be deleted)
    $res =~ s/=\n//g;               # rule #5 (soft line breaks)
    if (ord('A') == 193) { # EBCDIC style machine
        if (ord('[') == 173) {
            $res =~ s/=([\da-fA-F]{2})/Encode::encode('cp1047',Encode::decode('iso-8859-1',pack("C", hex($1))))/ge;
        }
        elsif (ord('[') == 187) {
            $res =~ s/=([\da-fA-F]{2})/Encode::encode('posix-bc',Encode::decode('iso-8859-1',pack("C", hex($1))))/ge;
        }
        elsif (ord('[') == 186) {
            $res =~ s/=([\da-fA-F]{2})/Encode::encode('cp37',Encode::decode('iso-8859-1',pack("C", hex($1))))/ge;
        }
    }
    else { # ASCII style machine
        $res =~ s/=([\da-fA-F]{2})/pack("C", hex($1))/ge;
    }
    $res;
}

sub decode_words
{
   my $value = shift || "";
   my $wd = default MIME::WordDecoder;

   eval "require Encode; $value = Encode::decode('MIME-Header', $value)";        

   $wd->handler("BIG5" => "KEEP");

   $wd->handler("WINDOWS-1250" => "KEEP");
   $wd->handler("WINDOWS-1251" => "KEEP");
   $wd->handler("WINDOWS-1252" => "KEEP");
   $wd->handler("WINDOWS-1253" => "KEEP");
   $wd->handler("WINDOWS-1254" => "KEEP");
   $wd->handler("WINDOWS-1255" => "KEEP");
   $wd->handler("WINDOWS-1256" => "KEEP");
   $wd->handler("WINDOWS-1257" => "KEEP");
   $wd->handler("WINDOWS-1258" => "KEEP");
   $wd->handler("ISO-8859-1" => \&decode_qp);
   $wd->handler("ISO-8859-2" => \&decode_qp);    

   my $retval = $value ? $wd->decode($value) : "";

   return ($retval == 1 ? $value : $retval);
}