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($boundary,'_part_'));
  79
  80             // the next four lines use strrev to reverse any nested boundaries
  81             // as a workaround for Courier-IMAP, which will stop parsing
  82             // when it sees the original outer boundary string and ignore
  83             // our "_part_..." addition to that string.  a bug report has been
  84             // made, but in the meantime...
  85             //
  86             } else if (strpos($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                     $length += $this->clean_crlf($body_part);
 158                     if ($stream) {
 159                         $this->preWriteToStream($body_part);
 160                         $this->writeToStream($stream, $body_part);
 161                     }
 162                     $last = $body_part;
 163                 }
 164                 fclose($file);
 165             }
 166             break;
 167         default:
 168             if ($message->body_part) {
 169                 $body_part = $message->body_part;
 170                 $length += $this->clean_crlf($body_part);
 171                 if ($stream) {
 172                     $this->writeToStream($stream, $body_part);
 173                 }
 174             } elseif ($message->att_local_name) {
 175                 $filename = $message->att_local_name;
 176                 $file = fopen ($filename, 'rb');
 177                 while ($tmp = fread($file, 570)) {
 178                    $body_part = chunk_split(base64_encode($tmp));
 179                     $length += $this->clean_crlf($body_part);
 180                     if ($stream) {
 181                         $this->writeToStream($stream, $body_part);
 182                     }
 183                 }
 184                 fclose($file);
 185             }
 186             break;
 187         }
 188         $body_part_trailing = '';
 189         if ($last && substr($last,-1) != "\n") {
 190             $body_part_trailing = "\r\n";
 191         }
 192         if ($body_part_trailing) {
 193             $length += strlen($body_part_trailing);
 194             if ($stream) {
 195                 $this->preWriteToStream($body_part_trailing);
 196                 $this->writeToStream($stream, $body_part_trailing);
 197             }
 198         }
 199     }
 200
 201     /**
 202      * function clean_crlf - change linefeeds and newlines to legal characters
 203      *
 204      * The SMTP format only allows CRLF as line terminators.
 205      * This function replaces illegal teminators with the correct terminator.
 206      *
 207      * @param string &$s string to clean linefeeds on
 208      *
 209      * @return void
 210      */
 211     function clean_crlf(&$s) {
 212         $s = str_replace("\r\n", "\n", $s);
 213         $s = str_replace("\r", "\n", $s);
 214         $s = str_replace("\n", "\r\n", $s);
 215         return strlen($s);
 216     }
 217
 218     /**
 219      * function strip_crlf - strip linefeeds and newlines from a string
 220      *
 221      * The SMTP format only allows CRLF as line terminators.
 222      * This function strips all line terminators from the string.
 223      *
 224      * @param string &$s string to clean linefeeds on
 225      *
 226      * @return void
 227      */
 228     function strip_crlf(&$s) {
 229         $s = str_replace("\r\n ", '', $s);
 230         $s = str_replace("\r", '', $s);
 231         $s = str_replace("\n", '', $s);
 232     }
 233
 234     /**
 235      * function preWriteToStream - reserved for extended functionality
 236      *
 237      * This function is not yet implemented.
 238      * Reserved for extended functionality.
 239      *
 240      * @param string &$s string to operate on
 241      *
 242      * @return void
 243      */
 244     function preWriteToStream(&$s) {
 245     }
 246
 247     /**
 248      * function writeToStream - write data to the SMTP stream
 249      *
 250      * @param resource $stream  SMTP output stream
 251      * @param string   $data    string with data to send to the SMTP stream
 252      *
 253      * @return void
 254      */
 255     function writeToStream($stream, $data) {
 256         fputs($stream, $data);
 257     }
 258
 259     /**
 260      * function initStream - reserved for extended functionality
 261      *
 262      * This function is not yet implemented.
 263      * Reserved for extended functionality.
 264      *
 265      * @param Message $message  Message object
 266      * @param string  $host     host name or IP to connect to
 267      * @param string  $user     username to log into the SMTP server with
 268      * @param string  $pass     password to log into the SMTP server with
 269      * @param integer $length
 270      *
 271      * @return handle $stream file handle resource to SMTP stream
 272      */
 273     function initStream($message, $length=0, $host='', $port='', $user='', $pass='') {
 274         return $stream;
 275     }
 276
 277     /**
 278      * function getBCC - reserved for extended functionality
 279      *
 280      * This function is not yet implemented.
 281      * Reserved for extended functionality.
 282      *
 283      */
 284     function getBCC() {
 285         return false;
 286     }
 287
 288     /**
 289      * function prepareMIME_Header - creates the mime header
 290      *
 291      * @param Message $message  Message object to act on
 292      * @param string  $boundary mime boundary from fn MimeBoundary
 293      *
 294      * @return string $header properly formatted mime header
 295      */
 296     function prepareMIME_Header($message, $boundary) {
 297         $mime_header = $message->mime_header;
 298         $rn="\r\n";
 299         $header = array();
 300
 301         $contenttype = 'Content-Type: '. $mime_header->type0 .'/'.
 302                         $mime_header->type1;
 303         if (count($message->entities)) {
 304             $contenttype .= ';' . 'boundary="'.$boundary.'"';
 305         }
 306         if (isset($mime_header->parameters['name'])) {
 307             $contenttype .= '; name="'.
 308             encodeHeader($mime_header->parameters['name']). '"';
 309         }
 310         if (isset($mime_header->parameters['charset'])) {
 311             $charset = $mime_header->parameters['charset'];
 312             $contenttype .= '; charset="'.
 313             encodeHeader($charset). '"';
 314         }
 315
 316         $header[] = $contenttype . $rn;
 317         if ($mime_header->description) {
 318             $header[] = 'Content-Description: ' . $mime_header->description . $rn;
 319         }
 320         if ($mime_header->encoding) {
 321             $header[] = 'Content-Transfer-Encoding: ' . $mime_header->encoding . $rn;
 322         } else {
 323             if ($mime_header->type0 == 'text' || $mime_header->type0 == 'message') {
 324                 $header[] = 'Content-Transfer-Encoding: 8bit' .  $rn;
 325             } else {
 326                 $header[] = 'Content-Transfer-Encoding: base64' .  $rn;
 327             }
 328         }
 329         if ($mime_header->id) {
 330             $header[] = 'Content-ID: ' . $mime_header->id . $rn;
 331         }
 332         if ($mime_header->disposition) {
 333             $disposition = $mime_header->disposition;
 334             $contentdisp = 'Content-Disposition: ' . $disposition->name;
 335             if ($disposition->getProperty('filename')) {
 336                 $contentdisp .= '; filename="'.
 337                 encodeHeader($disposition->getProperty('filename')). '"';
 338             }
 339             $header[] = $contentdisp . $rn;
 340         }
 341         if ($mime_header->md5) {
 342             $header[] = 'Content-MD5: ' . $mime_header->md5 . $rn;
 343         }
 344         if ($mime_header->language) {
 345             $header[] = 'Content-Language: ' . $mime_header->language . $rn;
 346         }
 347
 348         $cnt = count($header);
 349         $hdr_s = '';
 350         for ($i = 0 ; $i < $cnt ; $i++)    {
 351             $hdr_s .= $this->foldLine($header[$i], 78,str_pad('',4));
 352         }
 353         $header = $hdr_s;
 354         $header .= $rn; /* One blank line to separate mimeheader and body-entity */
 355         return $header;
 356     }
 357
 358     /**
 359      * function prepareRFC822_Header - prepares the RFC822 header string from Rfc822Header object(s)
 360      *
 361      * This function takes the Rfc822Header object(s) and formats them
 362      * into the RFC822Header string to send to the SMTP server as part
 363      * of the SMTP message.
 364      *
 365      * @param Rfc822Header  $rfc822_header
 366      * @param Rfc822Header  $reply_rfc822_header
 367      * @param integer      &$raw_length length of the message
 368      *
 369      * @return string $header
 370      */
 371     function prepareRFC822_Header($rfc822_header, $reply_rfc822_header, &$raw_length) {
 372         global $domain, $version, $username, $skip_SM_header;
 373
 374         /* if server var SERVER_NAME not available, use $domain */
 375         if(!sqGetGlobalVar('SERVER_NAME', $SERVER_NAME, SQ_SERVER)) {
 376             $SERVER_NAME = $domain;
 377         }
 378
 379         sqGetGlobalVar('REMOTE_ADDR', $REMOTE_ADDR, SQ_SERVER);
 380         sqGetGlobalVar('REMOTE_PORT', $REMOTE_PORT, SQ_SERVER);
 381         sqGetGlobalVar('REMOTE_HOST', $REMOTE_HOST, SQ_SERVER);
 382         sqGetGlobalVar('HTTP_VIA',    $HTTP_VIA,    SQ_SERVER);
 383         sqGetGlobalVar('HTTP_X_FORWARDED_FOR', $HTTP_X_FORWARDED_FOR, SQ_SERVER);
 384
 385         $rn = "\r\n";
 386
 387         /* This creates an RFC 822 date */
 388         $date = date('D, j M Y H:i:s ', mktime()) . $this->timezone();
 389         /* Create a message-id */
 390         $message_id = '<' . $REMOTE_PORT . '.' . $REMOTE_ADDR . '.';
 391         $message_id .= time() . '.squirrel@' . $SERVER_NAME .'>';
 392         /* Make an RFC822 Received: line */
 393         if (isset($REMOTE_HOST)) {
 394             $received_from = "$REMOTE_HOST ([$REMOTE_ADDR])";
 395         } else {
 396             $received_from = $REMOTE_ADDR;
 397         }
 398         if (isset($HTTP_VIA) || isset ($HTTP_X_FORWARDED_FOR)) {
 399             if (!isset($HTTP_X_FORWARDED_FOR) || $HTTP_X_FORWARDED_FOR == '') {
 400                 $HTTP_X_FORWARDED_FOR = 'unknown';
 401             }
 402             $received_from .= " (proxying for $HTTP_X_FORWARDED_FOR)";
 403         }
 404         $header = array();
 405         if ( !isset($skip_SM_header) || !$skip_SM_header )
 406         {
 407           $header[] = "Received: from $received_from" . $rn;
 408           $header[] = "        (SquirrelMail authenticated user $username)" . $rn;
 409           $header[] = "        by $SERVER_NAME with HTTP;" . $rn;
 410           $header[] = "        $date" . $rn;
 411         }
 412         /* Insert the rest of the header fields */
 413         $header[] = 'Message-ID: '. $message_id . $rn;
 414         if ($reply_rfc822_header->message_id) {
 415             $rep_message_id = $reply_rfc822_header->message_id;
 416         //        $this->strip_crlf($message_id);
 417             $header[] = 'In-Reply-To: '.$rep_message_id . $rn;
 418             $references = $this->calculate_references($reply_rfc822_header);
 419             $header[] = 'References: '.$references . $rn;
 420         }
 421         $header[] = "Date: $date" . $rn;
 422         $header[] = 'Subject: '.encodeHeader($rfc822_header->subject) . $rn;
 423         $header[] = 'From: '. $rfc822_header->getAddr_s('from',",$rn ",true) . $rn;
 424
 425         // folding address list [From|To|Cc|Bcc] happens by using ",$rn<space>" as delimiter
 426         // Do not use foldLine for that.
 427
 428         // RFC2822 if from contains more then 1 address
 429         if (count($rfc822_header->from) > 1) {
 430             $header[] = 'Sender: '. $rfc822_header->getAddr_s('sender',',',true) . $rn;
 431         }
 432         if (count($rfc822_header->to)) {
 433             $header[] = 'To: '. $rfc822_header->getAddr_s('to',",$rn ",true) . $rn;
 434         }
 435         if (count($rfc822_header->cc)) {
 436             $header[] = 'Cc: '. $rfc822_header->getAddr_s('cc',",$rn ",true) . $rn;
 437         }
 438         if (count($rfc822_header->reply_to)) {
 439             $header[] = 'Reply-To: '. $rfc822_header->getAddr_s('reply_to',',',true) . $rn;
 440         }
 441         /* Sendmail should return true. Default = false */
 442         $bcc = $this->getBcc();
 443         if (count($rfc822_header->bcc)) {
 444             $s = 'Bcc: '. $rfc822_header->getAddr_s('bcc',",$rn ",true) . $rn;
 445             if (!$bcc) {
 446                 $raw_length += strlen($s);
 447             } else {
 448                 $header[] = $s;
 449             }
 450         }
 451         /* Identify SquirrelMail */
 452         $header[] = 'User-Agent: SquirrelMail/' . $version . $rn;
 453         /* Do the MIME-stuff */
 454         $header[] = 'MIME-Version: 1.0' . $rn;
 455         $contenttype = 'Content-Type: '. $rfc822_header->content_type->type0 .'/'.
 456                                          $rfc822_header->content_type->type1;
 457         if (count($rfc822_header->content_type->properties)) {
 458             foreach ($rfc822_header->content_type->properties as $k => $v) {
 459                 if ($k && $v) {
 460                     $contenttype .= ';' .$k.'='.$v;
 461                 }
 462             }
 463         }
 464         $header[] = $contenttype . $rn;
 465         if ($encoding = $rfc822_header->encoding) {
 466             $header[] = 'Content-Transfer-Encoding: ' . $encoding .  $rn;
 467         }
 468         if ($rfc822_header->dnt) {
 469             $dnt = $rfc822_header->getAddr_s('dnt');
 470             /* Pegasus Mail */
 471             $header[] = 'X-Confirm-Reading-To: '.$dnt. $rn;
 472             /* RFC 2298 */
 473             $header[] = 'Disposition-Notification-To: '.$dnt. $rn;
 474         }
 475         if ($rfc822_header->priority) {
 476             switch($rfc822_header->priority)
 477             {
 478             case 1:
 479                 $header[] = 'X-Priority: 1 (Highest)'.$rn;
 480                 $header[] = 'Importance: High'. $rn; break;
 481             case 5:
 482                 $header[] = 'X-Priority: 5 (Lowest)'.$rn;
 483                 $header[] = 'Importance: Low'. $rn; break;
 484             default: break;
 485             }
 486         }
 487         /* Insert headers from the $more_headers array */
 488         if(count($rfc822_header->more_headers)) {
 489             reset($rfc822_header->more_headers);
 490             foreach ($rfc822_header->more_headers as $k => $v) {
 491                 $header[] = $k.': '.$v .$rn;
 492             }
 493         }
 494         $cnt = count($header);
 495         $hdr_s = '';
 496
 497         for ($i = 0 ; $i < $cnt ; $i++) {
 498             $sKey = substr($header[$i],0,strpos($header[$i],':'));
 499             switch ($sKey)
 500             {
 501             case 'Message-ID':
 502             case 'In-Reply_To':
 503                 $hdr_s .= $header[$i];
 504                 break;
 505             case 'References':
 506                 $sRefs = substr($header[$i],12);
 507                 $aRefs = explode(' ',$sRefs);
 508                 $sLine = 'References:';
 509                 foreach ($aRefs as $sReference) {
 510                     if (strlen($sLine)+strlen($sReference) >76) {
 511                         $hdr_s .= $sLine;
 512                         $sLine = $rn . '    ' . $sReference;
 513                     } else {
 514                         $sLine .= ' '. $sReference;
 515                     }
 516                 }
 517                 $hdr_s .= $sLine;
 518                 break;
 519             case 'To':
 520             case 'Cc':
 521             case 'Bcc':
 522             case 'From':
 523                 $hdr_s .= $header[$i];
 524                 break;
 525             default: $hdr_s .= $this->foldLine($header[$i], 78, str_pad('',4)); break;
 526             }
 527         }
 528         $header = $hdr_s;
 529         $header .= $rn; /* One blank line to separate header and body */
 530         $raw_length += strlen($header);
 531         return $header;
 532     }
 533
 534     /**
 535      * function foldLine - for cleanly folding of headerlines
 536      *
 537      * @param   string  $line
 538      * @param   integer $length length to fold the line at
 539      * @param   string  $pre    prefix the line with...
 540      *
 541      * @return string   $line folded line with trailing CRLF
 542      */
 543     function foldLine($line, $length, $pre='') {
 544         $line = substr($line,0, -2);
 545         $length -= 2; /* do not fold between \r and \n */
 546         $cnt = strlen($line);
 547         if ($cnt > $length) { /* try folding */
 548             $fold_string = "\r\n " . $pre;
 549             $bFirstFold = false;
 550             $aFoldLine = array();
 551             while (strlen($line) > $length) {
 552                 $fold = false;
 553                 /* handle encoded parts */
 554                 if (preg_match('/(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(\s+|.*)/Ui',$line,$regs)) {
 555                     $fold_tmp = $regs[1];
 556                     if (!trim($regs[5])) {
 557                         $fold_tmp .= $regs[5];
 558                     }
 559                     $iPosEnc = strpos($line,$fold_tmp);
 560                     $iLengthEnc = strlen($fold_tmp);
 561                     $iPosEncEnd = $iPosEnc+$iLengthEnc;
 562                     if ($iPosEnc < $length && (($iPosEncEnd) > $length)) {
 563                         $fold = true;
 564                         /* fold just before the start of the encoded string */
 565                         if ($iPosEnc) {
 566                             $aFoldLine[] = substr($line,0,$iPosEnc);
 567                         }
 568                         $line = substr($line,$iPosEnc);
 569                         if (!$bFirstFold) {
 570                             $bFirstFold = true;
 571                             $length -= strlen($fold_string);
 572                         }
 573                         if ($iLengthEnc > $length) { /* place the encoded
 574                             string on a separate line and do not fold inside it*/
 575                             /* minimize foldstring */
 576                             $fold_string = "\r\n ";
 577                             $aFoldLine[] = substr($line,0,$iLengthEnc);
 578                             $line = substr($line,$iLengthEnc);
 579                         }
 580                     } else if ($iPosEnc < $length) { /* the encoded string fits into the foldlength */
 581                         /*remainder */
 582                         $sLineRem = substr($line,$iPosEncEnd,$length - $iPosEncEnd);
 583                         if (preg_match('/^(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(.*)/Ui',$sLineRem) || !preg_match('/[=,;\s]/',$sLineRem)) {
 584                             /*impossible to fold clean in the next part -> fold after the enc string */
 585                             $aFoldLine[] = substr($line,0,$iPosEncEnd);
 586                             $line = substr($line,$iPosEncEnd);
 587                             $fold = true;
 588                             if (!$bFirstFold) {
 589                                 $bFirstFold = true;
 590                                 $length -= strlen($fold_string);
 591                             }
 592                         }
 593                     }
 594                 }
 595                 if (!$fold) {
 596                     $line_tmp = substr($line,0,$length);
 597                     $iFoldPos = false;
 598                     /* try to fold at logical places */
 599                     switch (true)
 600                     {
 601                     case ($iFoldPos = strrpos($line_tmp,',')): break;
 602                     case ($iFoldPos = strrpos($line_tmp,';')): break;
 603                     case ($iFoldPos = strrpos($line_tmp,' ')): break;
 604                     case ($iFoldPos = strrpos($line_tmp,'=')): break;
 605                     default: break;
 606                     }
 607
 608                     if (!$iFoldPos) { /* clean folding didn't work */
 609                         $iFoldPos = $length;
 610                     }
 611                     $aFoldLine[] = substr($line,0,$iFoldPos+1);
 612                     $line = substr($line,$iFoldPos+1);
 613                     if (!$bFirstFold) {
 614                         $bFirstFold = true;
 615                         $length -= strlen($fold_string);
 616                     }
 617                 }
 618             }
 619             /*$reconstruct the line */
 620             if ($line) {
 621                 $aFoldLine[] = $line;
 622             }
 623             $line = implode($fold_string,$aFoldLine);
 624         }
 625         return $line."\r\n";
 626     }
 627
 628     /**
 629      * function mimeBoundary - calculates the mime boundary to use
 630      *
 631      * This function will generate a random mime boundary base part
 632      * for the message if the boundary has not already been set.
 633      *
 634      * @return string $mimeBoundaryString random mime boundary string
 635      */
 636     function mimeBoundary () {
 637         static $mimeBoundaryString;
 638
 639         if ( !isset( $mimeBoundaryString ) ||
 640             $mimeBoundaryString == '') {
 641             $mimeBoundaryString = '----=_' . date( 'YmdHis' ) . '_' .
 642             mt_rand( 10000, 99999 );
 643         }
 644         return $mimeBoundaryString;
 645     }
 646
 647     /**
 648      * function timezone - Time offset for correct timezone
 649      *
 650      * @return string $result with timezone and offset
 651      */
 652     function timezone () {
 653         global $invert_time;
 654
 655         $diff_second = date('Z');
 656         if ($invert_time) {
 657             $diff_second = - $diff_second;
 658         }
 659         if ($diff_second > 0) {
 660             $sign = '+';
 661         } else {
 662             $sign = '-';
 663         }
 664         $diff_second = abs($diff_second);
 665         $diff_hour = floor ($diff_second / 3600);
 666         $diff_minute = floor (($diff_second-3600*$diff_hour) / 60);
 667         $zonename = '('.strftime('%Z').')';
 668         $result = sprintf ("%s%02d%02d %s", $sign, $diff_hour, $diff_minute,
 669                        $zonename);
 670         return ($result);
 671     }
 672
 673     /**
 674      * function calculate_references - calculate correct Referer string
 675      *
 676      * @param   Rfc822Header $hdr    message header to calculate from
 677      *
 678      * @return  string       $refer  concatenated and trimmed Referer string
 679      */
 680     function calculate_references($hdr) {
 681         $refer = $hdr->references;
 682         $message_id = $hdr->message_id;
 683         $in_reply_to = $hdr->in_reply_to;
 684         if (strlen($refer) > 2) {
 685             $refer .= ' ' . $message_id;
 686         } else {
 687             if ($in_reply_to) {
 688                 $refer .= $in_reply_to . ' ' . $message_id;
 689             } else {
 690                 $refer .= $message_id;
 691             }
 692         }
 693         trim($refer);
 694         return $refer;
 695     }
 696 }
 697 ?>