DeCoding.php
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<?php
namespace Helper\Mail;
/**
* 解码邮件内容
* @author：dc
* @time 2022/8/12 9:33
* Class DeCoding
* @package App\Mail\lib\MailParse
*/
class DeCoding {
/**
* @param $sText
* @param bool $bEmulate_imap_8bit
* @return string
* @author：dc
* @time 2022/8/12 9:34
*/
public static function de8bit($sText,$bEmulate_imap_8bit=true) {
// split text into lines
$aLines=explode(chr(13).chr(10),$sText);
for ($i=0;$i<count($aLines);$i++) {
$sLine =& $aLines[$i];
if (strlen($sLine)===0) continue; // do nothing, if empty
$sRegExp = '/[^\x09\x20\x21-\x3C\x3E-\x7E]/e';
// imap_8bit encodes x09 everywhere, not only at lineends,
// for EBCDIC safeness encode !"#$@[\]^`{|}~,
// for complete safeness encode every character :)
if ($bEmulate_imap_8bit)
$sRegExp = '/[^\x20\x21-\x3C\x3E-\x7E]/e';
$sReplmt = 'sprintf( "=%02X", ord ( "$0" ) ) ;';
$sLine = preg_replace( $sRegExp, $sReplmt, $sLine );
// encode x09,x20 at lineends
{
$iLength = strlen($sLine);
$iLastChar = ord($sLine{$iLength-1});
// !!!!!!!!
// imap_8_bit does not encode x20 at the very end of a text,
// here is, where I don't agree with imap_8_bit,
// please correct me, if I'm wrong,
// or comment next line for RFC2045 conformance, if you like
if (!($bEmulate_imap_8bit && ($i==count($aLines)-1)))
if (($iLastChar==0x09)||($iLastChar==0x20)) {
$sLine{$iLength-1}='=';
$sLine .= ($iLastChar==0x09)?'09':'20';
}
} // imap_8bit encodes x20 before chr(13), too
// although IMHO not requested by RFC2045, why not do it safer :)
// and why not encode any x20 around chr(10) or chr(13)
if ($bEmulate_imap_8bit) {
$sLine=str_replace(' =0D','=20=0D',$sLine);
//$sLine=str_replace(' =0A','=20=0A',$sLine);
//$sLine=str_replace('=0D ','=0D=20',$sLine);
//$sLine=str_replace('=0A ','=0A=20',$sLine);
}
// finally split into softlines no longer than 76 chars,
// for even more safeness one could encode x09,x20
// at the very first character of the line
// and after soft linebreaks, as well,
// but this wouldn't be caught by such an easy RegExp
preg_match_all( '/.{1,73}([^=]{0,2})?/', $sLine, $aMatch );
$sLine = implode( '=' . chr(13).chr(10), $aMatch[0] ); // add soft crlf's
}
// join lines into text
return implode(chr(13).chr(10),$aLines);
}
}