/**
* Encodes a header as per RFC2047
*
* @param string $name The header name
* @param string $value The header data to encode
* @param string $charset Character set name
* @param string $encoding Encoding name (base64 or quoted-printable)
* @param string $eol End-of-line sequence. Default: "\r\n"
*
* @return string Encoded header data (without a name)
* @access public
* @since 1.6.1
*/
function encodeHeader($name, $value, $charset='ISO-8859-1',
$encoding='quoted-printable', $eol="\r\n"
) {
// Structured headers
$comma_headers = array(
'from', 'to', 'cc', 'bcc', 'sender', 'reply-to',
'resent-from', 'resent-to', 'resent-cc', 'resent-bcc',
'resent-sender', 'resent-reply-to',
'return-receipt-to', 'disposition-notification-to',
);
$other_headers = array(
'references', 'in-reply-to', 'message-id', 'resent-message-id',
);
$name = strtolower($name);
if (in_array($name, $comma_headers)) {
$separator = ',';
} else if (in_array($name, $other_headers)) {
$separator = ' ';
}
if (!$charset) {
$charset = 'ISO-8859-1';
}
// Structured header (make sure addr-spec inside is not encoded)
if (!empty($separator)) {
// Simple e-mail address regexp
$email_regexp = '([^\s<]+|("[^\r\n"]+"))@\S+';
$parts = Mail_mimePart::_explodeQuotedString($separator, $value);
$value = '';
foreach ($parts as $part) {
$part = preg_replace('/\r?\n[\s\t]*/', $eol . ' ', $part);
$part = trim($part);
if (!$part) {
continue;
}
if ($value) {
$value .= $separator==',' ? $separator.' ' : ' ';
} else {
$value = $name . ': ';
}
// let's find phrase (name) and/or addr-spec
if (preg_match('/^<' . $email_regexp . '>$/', $part)) {
$value .= $part;
} else if (preg_match('/^' . $email_regexp . '$/', $part)) {
// address without brackets and without name
$value .= $part;
} else if (preg_match('/<*' . $email_regexp . '>*$/', $part, $matches)) {
// address with name (handle name)
$address = $matches[0];
$word = str_replace($address, '', $part);
$word = trim($word);
// check if phrase requires quoting
if ($word) {
// non-ASCII: require encoding
if (preg_match('#([\x80-\xFF]){1}#', $word)) {
if ($word[0] == '"' && $word[strlen($word)-1] == '"') {
// de-quote quoted-string, encoding changes
// string to atom
$search = array("\\\"", "\\\\");
$replace = array("\"", "\\");
$word = str_replace($search, $replace, $word);
$word = substr($word, 1, -1);
}
// find length of last line
if (($pos = strrpos($value, $eol)) !== false) {
$last_len = strlen($value) - $pos;
} else {
$last_len = strlen($value);
}
$word = Mail_mimePart::encodeHeaderValue(
$word, $charset, $encoding, $last_len, $eol
);
} else if (($word[0] != '"' || $word[strlen($word)-1] != '"')
&& preg_match('/[\(\)\<\>\\\.\[\]@,;:"]/', $word)
) {
// ASCII: quote string if needed
$word = '"'.addcslashes($word, '\\"').'"';
}
}
$value .= $word.' '.$address;
} else {
// addr-spec not found, don't encode (?)
$value .= $part;
}
// RFC2822 recommends 78 characters limit, use 76 from RFC2047
$value = wordwrap($value, 76, $eol . ' ');
}
// remove header name prefix (there could be EOL too)
$value = preg_replace(
'/^'.$name.':('.preg_quote($eol, '/').')* /', '', $value
);
} else {
// Unstructured header
// non-ASCII: require encoding
if (preg_match('#([\x80-\xFF]){1}#', $value)) {
if ($value[0] == '"' && $value[strlen($value)-1] == '"') {
// de-quote quoted-string, encoding changes
// string to atom
$search = array("\\\"", "\\\\");
$replace = array("\"", "\\");
$value = str_replace($search, $replace, $value);
$value = substr($value, 1, -1);
}
$value = Mail_mimePart::encodeHeaderValue(
$value, $charset, $encoding, strlen($name) + 2, $eol
);
} else if (strlen($name.': '.$value) > 78) {
// ASCII: check if header line isn't too long and use folding
$value = preg_replace('/\r?\n[\s\t]*/', $eol . ' ', $value);
$tmp = wordwrap($name.': '.$value, 78, $eol . ' ');
$value = preg_replace('/^'.$name.':\s*/', '', $tmp);
// hard limit 998 (RFC2822)
$value = wordwrap($value, 998, $eol . ' ', true);
}
}
return $value;
}