class/deliver/Deliver.class.php

   1 <?php
   2 /**
   3  * Deliver.class.php
   4  *
   5  * Copyright (c) 1999-2005 The SquirrelMail Project Team
   6  * Licensed under the GNU GPL. For full terms see the file COPYING.
   7  *
   8  * This contains all the functions needed to send messages through
   9  * a delivery backend.
  10  *
  11  * @version $Id$
  12  * @author  Marc Groot Koerkamp
  13  * @package squirrelmail
  14  */
  15
  16 /**
  17  * Deliver Class - called to actually deliver the message
  18  *
  19  * This class is called by compose.php and other code that needs
  20  * to send messages.  All delivery functionality should be centralized
  21  * in this class.
  22  *
  23  * Do not place UI code in this class, as UI code should be placed in templates
  24  * going forward.
  25  *
  26  * @author  Marc Groot Koerkamp
  27  * @package squirrelmail
  28  */
  29 class Deliver {
  30
  31     /**
  32      * function mail - send the message parts to the SMTP stream
  33      *
  34      * @param Message  $message  Message class to send
  35      * @param resource $stream   file handle to the SMTP stream
  36      *
  37      * @return integer $raw_length
  38      */
  39     function mail($message, $stream=false) {
  40         $rfc822_header = $message->rfc822_header;
  41         if (count($message->entities)) {
  42             $boundary = $this->mimeBoundary();
  43             $rfc822_header->content_type->properties['boundary']='"'.$boundary.'"';
  44         } else {
  45             $boundary='';
  46         }
  47         $raw_length = 0;
  48         $reply_rfc822_header = (isset($message->reply_rfc822_header)
  49                              ? $message->reply_rfc822_header : '');
  50         $header = $this->prepareRFC822_Header($rfc822_header, $reply_rfc822_header, $raw_length);
  51
  52         if ($stream) {
  53             $this->preWriteToStream($header);
  54             $this->writeToStream($stream, $header);
  55         }
  56         $this->writeBody($message, $stream, $raw_length, $boundary);
  57         return $raw_length;
  58     }
  59
  60     /**
  61      * function writeBody - generate and write the mime boundaries around each part to the stream
  62      *
  63      * Recursively formats and writes the MIME boundaries of the $message
  64      * to the output stream.
  65      *
  66      * @param Message   $message      Message object to transform
  67      * @param resource  $stream       SMTP output stream
  68      * @param integer  &$length_raw   raw length of the message (part)
  69      *                                as returned by mail fn
  70      * @param string    $boundary     custom boundary to call, usually for subparts
  71      *
  72      * @return void
  73      */
  74     function writeBody($message, $stream, &$length_raw, $boundary='') {
  75         // calculate boundary in case of multidimensional mime structures
  76         if ($boundary && $message->entity_id && count($message->entities)) {
  77             if (strpos($boundary,'_part_')) {
  78                 $boundary = substr($boundary,0,strpos($boundary,'_part_'));
  79
  80             // the next four lines use strrev to reverse any nested boundaries
  81             // because RFC 2046 (5.1.1) says that if a line starts with the outer
  82             // boundary string (doesn't matter what the line ends with), that
  83             // can be considered a match for the outer boundary; thus the nested
  84             // boundary needs to be unique from the outer one
  85             //
  86             } else if (strpos($boundary,'_trap_')) {
  87                 $boundary = substr(strrev($boundary),0,strpos(strrev($boundary),'_part_'));
  88             }
  89             $boundary_new = strrev($boundary . '_part_'.$message->entity_id);
  90         } else {
  91             $boundary_new = $boundary;
  92         }
  93         if ($boundary && !$message->rfc822_header) {
  94             $s = '--'.$boundary."\r\n";
  95             $s .= $this->prepareMIME_Header($message, $boundary_new);
  96             $length_raw += strlen($s);
  97             if ($stream) {
  98                 $this->preWriteToStream($s);
  99                 $this->writeToStream($stream, $s);
 100             }
 101         }
 102         $this->writeBodyPart($message, $stream, $length_raw);
 103
 104         $last = false;
 105         for ($i=0, $entCount=count($message->entities);$i<$entCount;$i++) {
 106             $msg = $this->writeBody($message->entities[$i], $stream, $length_raw, $boundary_new);
 107             if ($i == $entCount-1) $last = true;
 108         }
 109         if ($boundary && $last) {
 110             $s = "--".$boundary_new."--\r\n\r\n";
 111             $length_raw += strlen($s);
 112             if ($stream) {
 113                 $this->preWriteToStream($s);
 114                 $this->writeToStream($stream, $s);
 115             }
 116         }
 117     }
 118
 119     /**
 120      * function writeBodyPart - write each individual mimepart
 121      *
 122      * Recursively called by WriteBody to write each mime part to the SMTP stream
 123      *
 124      * @param Message   $message      Message object to transform
 125      * @param resource  $stream       SMTP output stream
 126      * @param integer  &$length       length of the message part
 127      *                                as returned by mail fn
 128      *
 129      * @return void
 130      */
 131     function writeBodyPart($message, $stream, &$length) {
 132         if ($message->mime_header) {
 133             $type0 = $message->mime_header->type0;
 134         } else {
 135             $type0 = $message->rfc822_header->content_type->type0;
 136         }
 137
 138         $body_part_trailing = $last = '';
 139         switch ($type0)
 140         {
 141         case 'text':
 142         case 'message':
 143             if ($message->body_part) {
 144                 $body_part = $message->body_part;
 145                 // remove NUL characters
 146                 $body_part = str_replace("\0",'',$body_part);
 147                 $length += $this->clean_crlf($body_part);
 148                 if ($stream) {
 149                     $this->preWriteToStream($body_part);
 150                     $this->writeToStream($stream, $body_part);
 151                 }
 152                 $last = $body_part;
 153             } elseif ($message->att_local_name) {
 154                 $filename = $message->att_local_name;
 155                 $file = fopen ($filename, 'rb');
 156                 while ($body_part = fgets($file, 4096)) {
 157                     // remove NUL characters
 158                     $body_part = str_replace("\0",'',$body_part);
 159                     $length += $this->clean_crlf($body_part);
 160                     if ($stream) {
 161                         $this->preWriteToStream($body_part);
 162                         $this->writeToStream($stream, $body_part);
 163                     }
 164                     $last = $body_part;
 165                 }
 166                 fclose($file);
 167             }
 168             break;
 169         default:
 170             if ($message->body_part) {
 171                 $body_part = $message->body_part;
 172                 // remove NUL characters
 173                 $body_part = str_replace("\0",'',$body_part);
 174                 $length += $this->clean_crlf($body_part);
 175                 if ($stream) {
 176                     $this->writeToStream($stream, $body_part);
 177                 }
 178             } elseif ($message->att_local_name) {
 179                 $filename = $message->att_local_name;
 180                 $file = fopen ($filename, 'rb');
 181                 while ($tmp = fread($file, 570)) {
 182                    $body_part = chunk_split(base64_encode($tmp));
 183                     $length += $this->clean_crlf($body_part);
 184                     if ($stream) {
 185                         $this->writeToStream($stream, $body_part);
 186                     }
 187                 }
 188                 fclose($file);
 189             }
 190             break;
 191         }
 192         $body_part_trailing = '';
 193         if ($last && substr($last,-1) != "\n") {
 194             $body_part_trailing = "\r\n";
 195         }
 196         if ($body_part_trailing) {
 197             $length += strlen($body_part_trailing);
 198             if ($stream) {
 199                 $this->preWriteToStream($body_part_trailing);
 200                 $this->writeToStream($stream, $body_part_trailing);
 201             }
 202         }
 203     }
 204
 205     /**
 206      * function clean_crlf - change linefeeds and newlines to legal characters
 207      *
 208      * The SMTP format only allows CRLF as line terminators.
 209      * This function replaces illegal teminators with the correct terminator.
 210      *
 211      * @param string &$s string to clean linefeeds on
 212      *
 213      * @return void
 214      */
 215     function clean_crlf(&$s) {
 216         $s = str_replace("\r\n", "\n", $s);
 217         $s = str_replace("\r", "\n", $s);
 218         $s = str_replace("\n", "\r\n", $s);
 219         return strlen($s);
 220     }
 221
 222     /**
 223      * function strip_crlf - strip linefeeds and newlines from a string
 224      *
 225      * The SMTP format only allows CRLF as line terminators.
 226      * This function strips all line terminators from the string.
 227      *
 228      * @param string &$s string to clean linefeeds on
 229      *
 230      * @return void
 231      */
 232     function strip_crlf(&$s) {
 233         $s = str_replace("\r\n ", '', $s);
 234         $s = str_replace("\r", '', $s);
 235         $s = str_replace("\n", '', $s);
 236     }
 237
 238     /**
 239      * function preWriteToStream - reserved for extended functionality
 240      *
 241      * This function is not yet implemented.
 242      * Reserved for extended functionality.
 243      *
 244      * @param string &$s string to operate on
 245      *
 246      * @return void
 247      */
 248     function preWriteToStream(&$s) {
 249     }
 250
 251     /**
 252      * function writeToStream - write data to the SMTP stream
 253      *
 254      * @param resource $stream  SMTP output stream
 255      * @param string   $data    string with data to send to the SMTP stream
 256      *
 257      * @return void
 258      */
 259     function writeToStream($stream, $data) {
 260         fputs($stream, $data);
 261     }
 262
 263     /**
 264      * function initStream - reserved for extended functionality
 265      *
 266      * This function is not yet implemented.
 267      * Reserved for extended functionality.
 268      *
 269      * @param Message $message  Message object
 270      * @param string  $host     host name or IP to connect to
 271      * @param string  $user     username to log into the SMTP server with
 272      * @param string  $pass     password to log into the SMTP server with
 273      * @param integer $length
 274      *
 275      * @return handle $stream file handle resource to SMTP stream
 276      */
 277     function initStream($message, $length=0, $host='', $port='', $user='', $pass='') {
 278         return $stream;
 279     }
 280
 281     /**
 282      * function getBCC - reserved for extended functionality
 283      *
 284      * This function is not yet implemented.
 285      * Reserved for extended functionality.
 286      *
 287      */
 288     function getBCC() {
 289         return false;
 290     }
 291
 292     /**
 293      * function prepareMIME_Header - creates the mime header
 294      *
 295      * @param Message $message  Message object to act on
 296      * @param string  $boundary mime boundary from fn MimeBoundary
 297      *
 298      * @return string $header properly formatted mime header
 299      */
 300     function prepareMIME_Header($message, $boundary) {
 301         $mime_header = $message->mime_header;
 302         $rn="\r\n";
 303         $header = array();
 304
 305         $contenttype = 'Content-Type: '. $mime_header->type0 .'/'.
 306                         $mime_header->type1;
 307         if (count($message->entities)) {
 308             $contenttype .= ';' . 'boundary="'.$boundary.'"';
 309         }
 310         if (isset($mime_header->parameters['name'])) {
 311             $contenttype .= '; name="'.
 312             encodeHeader($mime_header->parameters['name']). '"';
 313         }
 314         if (isset($mime_header->parameters['charset'])) {
 315             $charset = $mime_header->parameters['charset'];
 316             $contenttype .= '; charset="'.
 317             encodeHeader($charset). '"';
 318         }
 319
 320         $header[] = $contenttype . $rn;
 321         if ($mime_header->description) {
 322             $header[] = 'Content-Description: ' . $mime_header->description . $rn;
 323         }
 324         if ($mime_header->encoding) {
 325             $header[] = 'Content-Transfer-Encoding: ' . $mime_header->encoding . $rn;
 326         } else {
 327             if ($mime_header->type0 == 'text' || $mime_header->type0 == 'message') {
 328                 $header[] = 'Content-Transfer-Encoding: 8bit' .  $rn;
 329             } else {
 330                 $header[] = 'Content-Transfer-Encoding: base64' .  $rn;
 331             }
 332         }
 333         if ($mime_header->id) {
 334             $header[] = 'Content-ID: ' . $mime_header->id . $rn;
 335         }
 336         if ($mime_header->disposition) {
 337             $disposition = $mime_header->disposition;
 338             $contentdisp = 'Content-Disposition: ' . $disposition->name;
 339             if ($disposition->getProperty('filename')) {
 340                 $contentdisp .= '; filename="'.
 341                 encodeHeader($disposition->getProperty('filename')). '"';
 342             }
 343             $header[] = $contentdisp . $rn;
 344         }
 345         if ($mime_header->md5) {
 346             $header[] = 'Content-MD5: ' . $mime_header->md5 . $rn;
 347         }
 348         if ($mime_header->language) {
 349             $header[] = 'Content-Language: ' . $mime_header->language . $rn;
 350         }
 351
 352         $cnt = count($header);
 353         $hdr_s = '';
 354         for ($i = 0 ; $i < $cnt ; $i++)    {
 355             $hdr_s .= $this->foldLine($header[$i], 78,str_pad('',4));
 356         }
 357         $header = $hdr_s;
 358         $header .= $rn; /* One blank line to separate mimeheader and body-entity */
 359         return $header;
 360     }
 361
 362     /**
 363      * function prepareRFC822_Header - prepares the RFC822 header string from Rfc822Header object(s)
 364      *
 365      * This function takes the Rfc822Header object(s) and formats them
 366      * into the RFC822Header string to send to the SMTP server as part
 367      * of the SMTP message.
 368      *
 369      * @param Rfc822Header  $rfc822_header
 370      * @param Rfc822Header  $reply_rfc822_header
 371      * @param integer      &$raw_length length of the message
 372      *
 373      * @return string $header
 374      */
 375     function prepareRFC822_Header($rfc822_header, $reply_rfc822_header, &$raw_length) {
 376         global $domain, $version, $username, $skip_SM_header;
 377
 378         /* if server var SERVER_NAME not available, use $domain */
 379         if(!sqGetGlobalVar('SERVER_NAME', $SERVER_NAME, SQ_SERVER)) {
 380             $SERVER_NAME = $domain;
 381         }
 382
 383         sqGetGlobalVar('REMOTE_ADDR', $REMOTE_ADDR, SQ_SERVER);
 384         sqGetGlobalVar('REMOTE_PORT', $REMOTE_PORT, SQ_SERVER);
 385         sqGetGlobalVar('REMOTE_HOST', $REMOTE_HOST, SQ_SERVER);
 386         sqGetGlobalVar('HTTP_VIA',    $HTTP_VIA,    SQ_SERVER);
 387         sqGetGlobalVar('HTTP_X_FORWARDED_FOR', $HTTP_X_FORWARDED_FOR, SQ_SERVER);
 388
 389         $rn = "\r\n";
 390
 391         /* This creates an RFC 822 date */
 392         $date = date('D, j M Y H:i:s ', mktime()) . $this->timezone();
 393         /* Create a message-id */
 394         $message_id = '<' . $REMOTE_PORT . '.' . $REMOTE_ADDR . '.';
 395         $message_id .= time() . '.squirrel@' . $SERVER_NAME .'>';
 396         /* Make an RFC822 Received: line */
 397         if (isset($REMOTE_HOST)) {
 398             $received_from = "$REMOTE_HOST ([$REMOTE_ADDR])";
 399         } else {
 400             $received_from = $REMOTE_ADDR;
 401         }
 402         if (isset($HTTP_VIA) || isset ($HTTP_X_FORWARDED_FOR)) {
 403             if (!isset($HTTP_X_FORWARDED_FOR) || $HTTP_X_FORWARDED_FOR == '') {
 404                 $HTTP_X_FORWARDED_FOR = 'unknown';
 405             }
 406             $received_from .= " (proxying for $HTTP_X_FORWARDED_FOR)";
 407         }
 408         $header = array();
 409         if ( !isset($skip_SM_header) || !$skip_SM_header )
 410         {
 411           $header[] = "Received: from $received_from" . $rn;
 412           $header[] = "        (SquirrelMail authenticated user $username)" . $rn;
 413           $header[] = "        by $SERVER_NAME with HTTP;" . $rn;
 414           $header[] = "        $date" . $rn;
 415         }
 416         /* Insert the rest of the header fields */
 417         $header[] = 'Message-ID: '. $message_id . $rn;
 418         if ($reply_rfc822_header->message_id) {
 419             $rep_message_id = $reply_rfc822_header->message_id;
 420         //        $this->strip_crlf($message_id);
 421             $header[] = 'In-Reply-To: '.$rep_message_id . $rn;
 422             $references = $this->calculate_references($reply_rfc822_header);
 423             $header[] = 'References: '.$references . $rn;
 424         }
 425         $header[] = "Date: $date" . $rn;
 426         $header[] = 'Subject: '.encodeHeader($rfc822_header->subject) . $rn;
 427         $header[] = 'From: '. $rfc822_header->getAddr_s('from',",$rn ",true) . $rn;
 428
 429         // folding address list [From|To|Cc|Bcc] happens by using ",$rn<space>" as delimiter
 430         // Do not use foldLine for that.
 431
 432         // RFC2822 if from contains more then 1 address
 433         if (count($rfc822_header->from) > 1) {
 434             $header[] = 'Sender: '. $rfc822_header->getAddr_s('sender',',',true) . $rn;
 435         }
 436         if (count($rfc822_header->to)) {
 437             $header[] = 'To: '. $rfc822_header->getAddr_s('to',",$rn ",true) . $rn;
 438         }
 439         if (count($rfc822_header->cc)) {
 440             $header[] = 'Cc: '. $rfc822_header->getAddr_s('cc',",$rn ",true) . $rn;
 441         }
 442         if (count($rfc822_header->reply_to)) {
 443             $header[] = 'Reply-To: '. $rfc822_header->getAddr_s('reply_to',',',true) . $rn;
 444         }
 445         /* Sendmail should return true. Default = false */
 446         $bcc = $this->getBcc();
 447         if (count($rfc822_header->bcc)) {
 448             $s = 'Bcc: '. $rfc822_header->getAddr_s('bcc',",$rn ",true) . $rn;
 449             if (!$bcc) {
 450                 $raw_length += strlen($s);
 451             } else {
 452                 $header[] = $s;
 453             }
 454         }
 455         /* Identify SquirrelMail */
 456         $header[] = 'User-Agent: SquirrelMail/' . $version . $rn;
 457         /* Do the MIME-stuff */
 458         $header[] = 'MIME-Version: 1.0' . $rn;
 459         $contenttype = 'Content-Type: '. $rfc822_header->content_type->type0 .'/'.
 460                                          $rfc822_header->content_type->type1;
 461         if (count($rfc822_header->content_type->properties)) {
 462             foreach ($rfc822_header->content_type->properties as $k => $v) {
 463                 if ($k && $v) {
 464                     $contenttype .= ';' .$k.'='.$v;
 465                 }
 466             }
 467         }
 468         $header[] = $contenttype . $rn;
 469         if ($encoding = $rfc822_header->encoding) {
 470             $header[] = 'Content-Transfer-Encoding: ' . $encoding .  $rn;
 471         }
 472         if ($rfc822_header->dnt) {
 473             $dnt = $rfc822_header->getAddr_s('dnt');
 474             /* Pegasus Mail */
 475             $header[] = 'X-Confirm-Reading-To: '.$dnt. $rn;
 476             /* RFC 2298 */
 477             $header[] = 'Disposition-Notification-To: '.$dnt. $rn;
 478         }
 479         if ($rfc822_header->priority) {
 480             switch($rfc822_header->priority)
 481             {
 482             case 1:
 483                 $header[] = 'X-Priority: 1 (Highest)'.$rn;
 484                 $header[] = 'Importance: High'. $rn; break;
 485             case 5:
 486                 $header[] = 'X-Priority: 5 (Lowest)'.$rn;
 487                 $header[] = 'Importance: Low'. $rn; break;
 488             default: break;
 489             }
 490         }
 491         /* Insert headers from the $more_headers array */
 492         if(count($rfc822_header->more_headers)) {
 493             reset($rfc822_header->more_headers);
 494             foreach ($rfc822_header->more_headers as $k => $v) {
 495                 $header[] = $k.': '.$v .$rn;
 496             }
 497         }
 498         $cnt = count($header);
 499         $hdr_s = '';
 500
 501         for ($i = 0 ; $i < $cnt ; $i++) {
 502             $sKey = substr($header[$i],0,strpos($header[$i],':'));
 503             switch ($sKey)
 504             {
 505             case 'Message-ID':
 506             case 'In-Reply_To':
 507                 $hdr_s .= $header[$i];
 508                 break;
 509             case 'References':
 510                 $sRefs = substr($header[$i],12);
 511                 $aRefs = explode(' ',$sRefs);
 512                 $sLine = 'References:';
 513                 foreach ($aRefs as $sReference) {
 514                     if (strlen($sLine)+strlen($sReference) >76) {
 515                         $hdr_s .= $sLine;
 516                         $sLine = $rn . '    ' . $sReference;
 517                     } else {
 518                         $sLine .= ' '. $sReference;
 519                     }
 520                 }
 521                 $hdr_s .= $sLine;
 522                 break;
 523             case 'To':
 524             case 'Cc':
 525             case 'Bcc':
 526             case 'From':
 527                 $hdr_s .= $header[$i];
 528                 break;
 529             default: $hdr_s .= $this->foldLine($header[$i], 78, str_pad('',4)); break;
 530             }
 531         }
 532         $header = $hdr_s;
 533         $header .= $rn; /* One blank line to separate header and body */
 534         $raw_length += strlen($header);
 535         return $header;
 536     }
 537
 538     /**
 539      * function foldLine - for cleanly folding of headerlines
 540      *
 541      * @param   string  $line
 542      * @param   integer $length length to fold the line at
 543      * @param   string  $pre    prefix the line with...
 544      *
 545      * @return string   $line folded line with trailing CRLF
 546      */
 547     function foldLine($line, $length, $pre='') {
 548         $line = substr($line,0, -2);
 549         $length -= 2; /* do not fold between \r and \n */
 550         $cnt = strlen($line);
 551         if ($cnt > $length) { /* try folding */
 552             $fold_string = "\r\n " . $pre;
 553             $bFirstFold = false;
 554             $aFoldLine = array();
 555             while (strlen($line) > $length) {
 556                 $fold = false;
 557                 /* handle encoded parts */
 558                 if (preg_match('/(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(\s+|.*)/Ui',$line,$regs)) {
 559                     $fold_tmp = $regs[1];
 560                     if (!trim($regs[5])) {
 561                         $fold_tmp .= $regs[5];
 562                     }
 563                     $iPosEnc = strpos($line,$fold_tmp);
 564                     $iLengthEnc = strlen($fold_tmp);
 565                     $iPosEncEnd = $iPosEnc+$iLengthEnc;
 566                     if ($iPosEnc < $length && (($iPosEncEnd) > $length)) {
 567                         $fold = true;
 568                         /* fold just before the start of the encoded string */
 569                         if ($iPosEnc) {
 570                             $aFoldLine[] = substr($line,0,$iPosEnc);
 571                         }
 572                         $line = substr($line,$iPosEnc);
 573                         if (!$bFirstFold) {
 574                             $bFirstFold = true;
 575                             $length -= strlen($fold_string);
 576                         }
 577                         if ($iLengthEnc > $length) { /* place the encoded
 578                             string on a separate line and do not fold inside it*/
 579                             /* minimize foldstring */
 580                             $fold_string = "\r\n ";
 581                             $aFoldLine[] = substr($line,0,$iLengthEnc);
 582                             $line = substr($line,$iLengthEnc);
 583                         }
 584                     } else if ($iPosEnc < $length) { /* the encoded string fits into the foldlength */
 585                         /*remainder */
 586                         $sLineRem = substr($line,$iPosEncEnd,$length - $iPosEncEnd);
 587                         if (preg_match('/^(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(.*)/Ui',$sLineRem) || !preg_match('/[=,;\s]/',$sLineRem)) {
 588                             /*impossible to fold clean in the next part -> fold after the enc string */
 589                             $aFoldLine[] = substr($line,0,$iPosEncEnd);
 590                             $line = substr($line,$iPosEncEnd);
 591                             $fold = true;
 592                             if (!$bFirstFold) {
 593                                 $bFirstFold = true;
 594                                 $length -= strlen($fold_string);
 595                             }
 596                         }
 597                     }
 598                 }
 599                 if (!$fold) {
 600                     $line_tmp = substr($line,0,$length);
 601                     $iFoldPos = false;
 602                     /* try to fold at logical places */
 603                     switch (true)
 604                     {
 605                     case ($iFoldPos = strrpos($line_tmp,',')): break;
 606                     case ($iFoldPos = strrpos($line_tmp,';')): break;
 607                     case ($iFoldPos = strrpos($line_tmp,' ')): break;
 608                     case ($iFoldPos = strrpos($line_tmp,'=')): break;
 609                     default: break;
 610                     }
 611
 612                     if (!$iFoldPos) { /* clean folding didn't work */
 613                         $iFoldPos = $length;
 614                     }
 615                     $aFoldLine[] = substr($line,0,$iFoldPos+1);
 616                     $line = substr($line,$iFoldPos+1);
 617                     if (!$bFirstFold) {
 618                         $bFirstFold = true;
 619                         $length -= strlen($fold_string);
 620                     }
 621                 }
 622             }
 623             /*$reconstruct the line */
 624             if ($line) {
 625                 $aFoldLine[] = $line;
 626             }
 627             $line = implode($fold_string,$aFoldLine);
 628         }
 629         return $line."\r\n";
 630     }
 631
 632     /**
 633      * function mimeBoundary - calculates the mime boundary to use
 634      *
 635      * This function will generate a random mime boundary base part
 636      * for the message if the boundary has not already been set.
 637      *
 638      * @return string $mimeBoundaryString random mime boundary string
 639      */
 640     function mimeBoundary () {
 641         static $mimeBoundaryString;
 642
 643         if ( !isset( $mimeBoundaryString ) ||
 644             $mimeBoundaryString == '') {
 645             $mimeBoundaryString = '----=_' . date( 'YmdHis' ) . '_' .
 646             mt_rand( 10000, 99999 );
 647         }
 648         return $mimeBoundaryString;
 649     }
 650
 651     /**
 652      * function timezone - Time offset for correct timezone
 653      *
 654      * @return string $result with timezone and offset
 655      */
 656     function timezone () {
 657         global $invert_time;
 658
 659         $diff_second = date('Z');
 660         if ($invert_time) {
 661             $diff_second = - $diff_second;
 662         }
 663         if ($diff_second > 0) {
 664             $sign = '+';
 665         } else {
 666             $sign = '-';
 667         }
 668         $diff_second = abs($diff_second);
 669         $diff_hour = floor ($diff_second / 3600);
 670         $diff_minute = floor (($diff_second-3600*$diff_hour) / 60);
 671         $zonename = '('.strftime('%Z').')';
 672         $result = sprintf ("%s%02d%02d %s", $sign, $diff_hour, $diff_minute,
 673                        $zonename);
 674         return ($result);
 675     }
 676
 677     /**
 678      * function calculate_references - calculate correct Referer string
 679      *
 680      * @param   Rfc822Header $hdr    message header to calculate from
 681      *
 682      * @return  string       $refer  concatenated and trimmed Referer string
 683      */
 684     function calculate_references($hdr) {
 685         $refer = $hdr->references;
 686         $message_id = $hdr->message_id;
 687         $in_reply_to = $hdr->in_reply_to;
 688         if (strlen($refer) > 2) {
 689             $refer .= ' ' . $message_id;
 690         } else {
 691             if ($in_reply_to) {
 692                 $refer .= $in_reply_to . ' ' . $message_id;
 693             } else {
 694                 $refer .= $message_id;
 695             }
 696         }
 697         trim($refer);
 698         return $refer;
 699     }
 700 }
 701 ?>