protected function _encodeHeader($value)
{
if (Zend_Mime::isPrintable($value) === false) {
if ($this->getHeaderEncoding() === Zend_Mime::ENCODING_QUOTEDPRINTABLE) {
$value = Zend_Mime::encodeQuotedPrintableHeader($value, $this->getCharset(), Zend_Mime::LINELENGTH, Zend_Mime::LINEEND);
} else {
$value = Zend_Mime::encodeBase64Header($value, $this->getCharset(), Zend_Mime::LINELENGTH, Zend_Mime::LINEEND);
}
}
return $value;
}