function encode_header($str, $position = 'text', $force = false)
{
$encode_charset = 'ISO-2022-JP';
//ToDo: Initialize with $this->Charset, but it won't work well now.
if (function_exists('mb_convert_encoding')) {
//Using mb_string extension if exists.
if ($this->needs_encode || $force) {
$str_encoding = mb_detect_encoding($str, 'ASCII,' . $encode_charset);
if ($str_encoding == 'ASCII') {
// Return original if string from only ASCII chars.
return $str;
} else {
if ($str_encoding != $encode_charset) {
// Maybe this case may not occur.
$str = mb_convert_encoding($str, $encode_charset, $str_encoding);
}
}
//Following Logic are made for recovering PHP4.4.x mb_encode_mimeheader() bug.
//TODO: If mb_encode_mimeheader() bug is fixed. Replace this to simple logic.
$cut_start = 0;
$encoded = '';
$cut_length = floor((76 - strlen('Subject: =?' . $encode_charset . '?B?' . '?=')) / 4) * 3;
while ($cut_start < strlen($str)) {
$partstr = mb_strcut($str, $cut_start, $cut_length, $encode_charset);
$partstr_length = strlen($partstr);
if (!$partstr_length) {
break;
}
if ($encode_charset == 'ISO-2022-JP') {
//Should Adjust next cutting place for SO & SI char insertion.
if (substr($partstr, 0, 3) === chr(27) . '$B' && substr($str, $cut_start, 3) !== chr(27) . '$B') {
$partstr_length -= 3;
}
if (substr($partstr, -3) === chr(27) . '(B' && substr($str, $cut_start + $partstr_length - 3, 3) !== chr(27) . '(B') {
$partstr_length -= 3;
}
}
if ($cut_start) {
$encoded .= "\r\n\t";
}
$encoded .= '=?' . $encode_charset . '?B?' . base64_encode($partstr) . '?=';
$cut_start += $partstr_length;
}
} else {
$encoded = $str;
}
} else {
$encoded = parent::encode_header($str, $position);
}
return $encoded;
}
