You are here

Home » API reference » Quiz 6.6 » pclzip.lib.php » PclZip

function PclZip::privReadEndCentralDir in Quiz 6.6

Same name and namespace in other branches
  1. 6.5 includes/moodle/lib/pclzip/pclzip.lib.php \PclZip::privReadEndCentralDir()
6 calls to PclZip::privReadEndCentralDir()
PclZip::privAdd in includes/moodle/lib/pclzip/pclzip.lib.php
PclZip::privDeleteByRule in includes/moodle/lib/pclzip/pclzip.lib.php
PclZip::privExtractByRule in includes/moodle/lib/pclzip/pclzip.lib.php
PclZip::privList in includes/moodle/lib/pclzip/pclzip.lib.php
PclZip::privMerge in includes/moodle/lib/pclzip/pclzip.lib.php

... See full list

File

includes/moodle/lib/pclzip/pclzip.lib.php, line 4392

Class

PclZip

Code

function privReadEndCentralDir(&$p_central_dir) {

  //--(MAGIC-PclTrace)--//PclTraceFctStart(__FILE__, __LINE__, "PclZip::privReadEndCentralDir", "");
  $v_result = 1;

  // ----- Go to the end of the zip file
  $v_size = filesize($this->zipname);

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 2, "Size of the file :$v_size");
  @fseek($this->zip_fd, $v_size);

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Position at end of zip file : \''.ftell($this->zip_fd).'\'');
  if (@ftell($this->zip_fd) != $v_size) {

    // ----- Error log
    PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, 'Unable to go to the end of the archive \'' . $this->zipname . '\'');

    // ----- Return

    //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
    return PclZip::errorCode();
  }

  // ----- First try : look if this is an archive with no commentaries (most of the time)
  // in this case the end of central dir is at 22 bytes of the file end
  $v_found = 0;
  if ($v_size > 26) {

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Look for central dir with no comment');
    @fseek($this->zip_fd, $v_size - 22);

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Position after min central position : \''.ftell($this->zip_fd).'\'');
    if (($v_pos = @ftell($this->zip_fd)) != $v_size - 22) {

      // ----- Error log
      PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, 'Unable to seek back to the middle of the archive \'' . $this->zipname . '\'');

      // ----- Return

      //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
      return PclZip::errorCode();
    }

    // ----- Read for bytes
    $v_binary_data = @fread($this->zip_fd, 4);

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 5, "Binary data is : '".sprintf("%08x", $v_binary_data)."'");
    $v_data = @unpack('Vid', $v_binary_data);

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, "Binary signature is : '".sprintf("0x%08x", $v_data['id'])."'");

    // ----- Check signature
    if ($v_data['id'] == 0x6054b50) {

      //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 2, "Found central dir at the default position.");
      $v_found = 1;
    }
    $v_pos = ftell($this->zip_fd);
  }

  // ----- Go back to the maximum possible size of the Central Dir End Record
  if (!$v_found) {

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Start extended search of end central dir');
    $v_maximum_size = 65557;

    // 0xFFFF + 22;
    if ($v_maximum_size > $v_size) {
      $v_maximum_size = $v_size;
    }
    @fseek($this->zip_fd, $v_size - $v_maximum_size);
    if (@ftell($this->zip_fd) != $v_size - $v_maximum_size) {

      // ----- Error log
      PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, 'Unable to seek back to the middle of the archive \'' . $this->zipname . '\'');

      // ----- Return

      //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
      return PclZip::errorCode();
    }

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Position after max central position : \''.ftell($this->zip_fd).'\'');

    // ----- Read byte per byte in order to find the signature
    $v_pos = ftell($this->zip_fd);
    $v_bytes = 0x0;
    while ($v_pos < $v_size) {

      // ----- Read a byte
      $v_byte = @fread($this->zip_fd, 1);

      // -----  Add the byte
      $v_bytes = $v_bytes << 8 | Ord($v_byte);

      // ----- Compare the bytes
      if ($v_bytes == 0x504b0506) {

        //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, 'Found End Central Dir signature at position : \''.ftell($this->zip_fd).'\'');
        $v_pos++;
        break;
      }
      $v_pos++;
    }

    // ----- Look if not found end of central dir
    if ($v_pos == $v_size) {

      //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 2, "Unable to find End of Central Dir Record signature");

      // ----- Error log
      PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, "Unable to find End of Central Dir Record signature");

      // ----- Return

      //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
      return PclZip::errorCode();
    }
  }

  // ----- Read the first 18 bytes of the header
  $v_binary_data = fread($this->zip_fd, 18);

  // ----- Look for invalid block size
  if (strlen($v_binary_data) != 18) {

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 2, "Invalid End of Central Dir Record size : ".strlen($v_binary_data));

    // ----- Error log
    PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, "Invalid End of Central Dir Record size : " . strlen($v_binary_data));

    // ----- Return

    //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
    return PclZip::errorCode();
  }

  // ----- Extract the values

  ////--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, "Central Dir Record : '".$v_binary_data."'");

  ////--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 4, "Central Dir Record (Hex) : '".bin2hex($v_binary_data)."'");
  $v_data = unpack('vdisk/vdisk_start/vdisk_entries/ventries/Vsize/Voffset/vcomment_size', $v_binary_data);

  // ----- Check the global size

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, "Comment length : ".$v_data['comment_size']);
  if ($v_pos + $v_data['comment_size'] + 18 != $v_size) {

    //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 2, "The central dir is not at the end of the archive. Some trailing bytes exists after the archive.");

    // ----- Removed in release 2.2 see readme file
    // The check of the file size is a little too strict.
    // Some bugs where found when a zip is encrypted/decrypted with 'crypt'.
    // While decrypted, zip has training 0 bytes
    if (0) {

      // ----- Error log
      PclZip::privErrorLog(PCLZIP_ERR_BAD_FORMAT, 'The central dir is not at the end of the archive.' . ' Some trailing bytes exists after the archive.');

      // ----- Return

      //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, PclZip::errorCode(), PclZip::errorInfo());
      return PclZip::errorCode();
    }
  }

  // ----- Get comment
  if ($v_data['comment_size'] != 0) {
    $p_central_dir['comment'] = fread($this->zip_fd, $v_data['comment_size']);
  }
  else {
    $p_central_dir['comment'] = '';
  }

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Comment : \''.$p_central_dir['comment'].'\'');
  $p_central_dir['entries'] = $v_data['entries'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Nb of entries : \''.$p_central_dir['entries'].'\'');
  $p_central_dir['disk_entries'] = $v_data['disk_entries'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Nb of entries for this disk : \''.$p_central_dir['disk_entries'].'\'');
  $p_central_dir['offset'] = $v_data['offset'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Offset of Central Dir : \''.$p_central_dir['offset'].'\'');
  $p_central_dir['size'] = $v_data['size'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Size of Central Dir : \''.$p_central_dir['size'].'\'');
  $p_central_dir['disk'] = $v_data['disk'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Disk number : \''.$p_central_dir['disk'].'\'');
  $p_central_dir['disk_start'] = $v_data['disk_start'];

  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, 'Start disk number : \''.$p_central_dir['disk_start'].'\'');

  // TBC

  //for(reset($p_central_dir); $key = key($p_central_dir); next($p_central_dir)) {

  //  //--(MAGIC-PclTrace)--//PclTraceFctMessage(__FILE__, __LINE__, 3, "central_dir[$key] = ".$p_central_dir[$key]);

  //}

  // ----- Return

  //--(MAGIC-PclTrace)--//PclTraceFctEnd(__FILE__, __LINE__, $v_result);
  return $v_result;
}