class Archive_Tar

system_autoload_info in core/modules/system/system.module

Implements hook_autoload_info().

class Archive_Tar
 {
  /**
   * @var string Name of the Tar
   */
  public $_tarname = '';

  /**
   * @var boolean if true, the Tar file will be gzipped
   */
  public $_compress = false;

  /**
   * @var string Type of compression : 'none', 'gz', 'bz2' or 'lzma2'
   */
  public $_compress_type = 'none';

  /**
   * @var string Explode separator
   */
  public $_separator = ' ';

  /**
   * @var file descriptor
   */
  public $_file = 0;

  /**
   * @var string Local Tar name of a remote Tar (http:// or ftp://)
   */
  public $_temp_tarname = '';

  /**
   * @var string regular expression for ignoring files or directories
   */
  public $_ignore_regexp = '';

  /**
   * @var object PEAR_Error object
   */
  public $error_object = null;

  /**
   * Format for data extraction
   *
   * @var string
   */
  public $_fmt = '';

  /**
   * @var int Length of the read buffer in bytes
   */
  protected $buffer_length;

  /**
   * Archive_Tar Class constructor. This flavour of the constructor only
   * declare a new Archive_Tar object, identifying it by the name of the
   * tar file.
   * If the compress argument is set the tar will be read or created as a
   * gzip or bz2 compressed TAR file.
   *
   * @param string $p_tarname The name of the tar archive to create
   * @param string $p_compress can be null, 'gz', 'bz2' or 'lzma2'. This
   *               parameter indicates if gzip, bz2 or lzma2 compression
   *               is required.  For compatibility reason the
   *               boolean value 'true' means 'gz'.
   * @param int $buffer_length Length of the read buffer in bytes
   *
   * @return bool
   */
  public function __construct($p_tarname, $p_compress = null, $buffer_length = 512) 
   {
    // Backdrop removal parent::__construct().

    $this->_compress = false;
    $this->_compress_type = 'none';
    if (($p_compress === null) || ($p_compress == '')) {
      if (@file_exists($p_tarname)) {
        if ($fp = @fopen($p_tarname, "rb")) {
          // look for gzip magic cookie
          $data = fread($fp, 2);
          fclose($fp);
          if ($data == "\37\213") {
            $this->_compress = true;
            $this->_compress_type = 'gz';
            // Not sure it's enough for a magic code.
          }
          elseif ($data == "BZ") {
            $this->_compress = true;
            $this->_compress_type = 'bz2';
          }
          elseif (file_get_contents($p_tarname, false, null, 1, 4) == '7zXZ') {
            $this->_compress = true;
            $this->_compress_type = 'lzma2';
          }
        }
      }
      else {
        // probably a remote file or some file accessible
        // through a stream interface
        if (substr($p_tarname, -2) == 'gz') {
          $this->_compress = true;
          $this->_compress_type = 'gz';
        }
        elseif ((substr($p_tarname, -3) == 'bz2') || 
          (substr($p_tarname, -2) == 'bz')
          ) {
          $this->_compress = true;
          $this->_compress_type = 'bz2';
        }
        else {
          if (substr($p_tarname, -2) == 'xz') {
            $this->_compress = true;
            $this->_compress_type = 'lzma2';
          }
        }
      }
    }
    else {
      if (($p_compress === true) || ($p_compress == 'gz')) {
        $this->_compress = true;
        $this->_compress_type = 'gz';
      }
      else {
        if ($p_compress == 'bz2') {
          $this->_compress = true;
          $this->_compress_type = 'bz2';
        }
        else {
          if ($p_compress == 'lzma2') {
            $this->_compress = true;
            $this->_compress_type = 'lzma2';
          }
          else {
            $this->_error(
            "Unsupported compression type '$p_compress'\n" .
            "Supported types are 'gz', 'bz2' and 'lzma2'.\n"
            );
            return false;
          }
        }
      }
    }
    $this->_tarname = $p_tarname;
    if ($this->_compress) { // assert zlib or bz2 or xz extension support
      if ($this->_compress_type == 'gz') {
        $extname = 'zlib';
      }
      else {
        if ($this->_compress_type == 'bz2') {
          $extname = 'bz2';
        }
        else {
          if ($this->_compress_type == 'lzma2') {
            $extname = 'xz';
          }
        }
      }

      if (!extension_loaded($extname)) {
        // Backdrop change PEAR::loadExtension($extname).
        $this->loadExtension($extname);
      }
      if (!extension_loaded($extname)) {
        $this->_error(
        "The extension '$extname' couldn't be found.\n" .
        "Please make sure your version of PHP was built " .
          "with '$extname' support.\n"
          );
        return false;
      }
    }

    if (version_compare(PHP_VERSION, "5.5.0-dev") < 0) {
      $this->_fmt = "a100filename/a8mode/a8uid/a8gid/a12size/a12mtime/" .
        "a8checksum/a1typeflag/a100link/a6magic/a2version/" .
        "a32uname/a32gname/a8devmajor/a8devminor/a131prefix";
    }
    else {
      $this->_fmt = "Z100filename/Z8mode/Z8uid/Z8gid/Z12size/Z12mtime/" .
        "Z8checksum/Z1typeflag/Z100link/Z6magic/Z2version/" .
        "Z32uname/Z32gname/Z8devmajor/Z8devminor/Z131prefix";
    }

    $this->buffer_length = $buffer_length;
  }

  public function __destruct() 
   {
    $this->_close();
    // ----- Look for a local copy to delete
    if ($this->_temp_tarname != '' && (bool) preg_match('/^tar[[:alnum:]]*\.tmp$/', $this->_temp_tarname)) {
      @backdrop_unlink($this->_temp_tarname);
    }
  }

  // Backdrop addition from PEAR.php.
  /**
   * OS independent PHP extension load. Remember to take care
   * on the correct extension name for case sensitive OSes.
   *
   * @param string $ext The extension name
   * @return bool Success or not on the dl() call
   */
  public static function loadExtension($ext) 
   {
    if (extension_loaded($ext)) {
      return true;
    }

    // if either returns true dl() will produce a FATAL error, stop that
    if (
    function_exists('dl') === false || 
      ini_get('enable_dl') != 1
      ) {
      return false;
    }

    if (OS_WINDOWS) {
      $suffix = '.dll';
    }
    elseif (PHP_OS == 'HP-UX') {
      $suffix = '.sl';
    }
    elseif (PHP_OS == 'AIX') {
      $suffix = '.a';
    }
    elseif (PHP_OS == 'OSX') {
      $suffix = '.bundle';
    }
    else {
      $suffix = '.so';
    }

    return @dl('php_' . $ext . $suffix) || @dl($ext . $suffix);
  }


  /**
   * This method creates the archive file and add the files / directories
   * that are listed in $p_filelist.
   * If a file with the same name exist and is writable, it is replaced
   * by the new tar.
   * The method return false and a PEAR error text.
   * The $p_filelist parameter can be an array of string, each string
   * representing a filename or a directory name with their path if
   * needed. It can also be a single string with names separated by a
   * single blank.
   * For each directory added in the archive, the files and
   * sub-directories are also added.
   * See also createModify() method for more details.
   *
   * @param array $p_filelist An array of filenames and directory names, or a
   *              single string with names separated by a single
   *              blank space.
   *
   * @return bool true on success, false on error.
   * @see    createModify()
   */
  public function create($p_filelist) 
   {
    return $this->createModify($p_filelist, '', '');
  }

  /**
   * This method add the files / directories that are listed in $p_filelist in
   * the archive. If the archive does not exist it is created.
   * The method return false and a PEAR error text.
   * The files and directories listed are only added at the end of the archive,
   * even if a file with the same name is already archived.
   * See also createModify() method for more details.
   *
   * @param array $p_filelist An array of filenames and directory names, or a
   *              single string with names separated by a single
   *              blank space.
   *
   * @return bool true on success, false on error.
   * @see    createModify()
   * @access public
   */
  public function add($p_filelist) 
   {
    return $this->addModify($p_filelist, '', '');
  }

  /**
   * @param string $p_path
   * @param bool $p_preserve
   * @param bool $p_symlinks
   * @return bool
   */
  public function extract($p_path = '', $p_preserve = false, $p_symlinks = true) 
   {
    return $this->extractModify($p_path, '', $p_preserve, $p_symlinks);
  }

  /**
   * @return array|int
   */
  public function listContent() 
   {
    $v_list_detail = array();

    if ($this->_openRead()) {
      if (!$this->_extractList('', $v_list_detail, "list", '', '')) {
        unset($v_list_detail);
        $v_list_detail = 0;
      }
      $this->_close();
    }

    return $v_list_detail;
  }

  /**
   * This method creates the archive file and add the files / directories
   * that are listed in $p_filelist.
   * If the file already exists and is writable, it is replaced by the
   * new tar. It is a create and not an add. If the file exists and is
   * read-only or is a directory it is not replaced. The method return
   * false and a PEAR error text.
   * The $p_filelist parameter can be an array of string, each string
   * representing a filename or a directory name with their path if
   * needed. It can also be a single string with names separated by a
   * single blank.
   * The path indicated in $p_remove_dir will be removed from the
   * memorized path of each file / directory listed when this path
   * exists. By default nothing is removed (empty path '')
   * The path indicated in $p_add_dir will be added at the beginning of
   * the memorized path of each file / directory listed. However it can
   * be set to empty ''. The adding of a path is done after the removing
   * of path.
   * The path add/remove ability enables the user to prepare an archive
   * for extraction in a different path than the origin files are.
   * See also addModify() method for file adding properties.
   *
   * @param array $p_filelist An array of filenames and directory names,
   *                             or a single string with names separated by
   *                             a single blank space.
   * @param string $p_add_dir A string which contains a path to be added
   *                             to the memorized path of each element in
   *                             the list.
   * @param string $p_remove_dir A string which contains a path to be
   *                             removed from the memorized path of each
   *                             element in the list, when relevant.
   *
   * @return boolean true on success, false on error.
   * @see addModify()
   */
  public function createModify($p_filelist, $p_add_dir, $p_remove_dir = '') 
   {
    $v_result = true;

    if (!$this->_openWrite()) {
      return false;
    }

    if ($p_filelist != '') {
      if (is_array($p_filelist)) {
        $v_list = $p_filelist;
      }
      elseif (is_string($p_filelist)) {
        $v_list = explode($this->_separator, $p_filelist);
      }
      else {
        $this->_cleanFile();
        $this->_error('Invalid file list');
        return false;
      }

      $v_result = $this->_addList($v_list, $p_add_dir, $p_remove_dir);
    }

    if ($v_result) {
      $this->_writeFooter();
      $this->_close();
    }
    else {
      $this->_cleanFile();
    }

    return $v_result;
  }

  /**
   * This method add the files / directories listed in $p_filelist at the
   * end of the existing archive. If the archive does not yet exists it
   * is created.
   * The $p_filelist parameter can be an array of string, each string
   * representing a filename or a directory name with their path if
   * needed. It can also be a single string with names separated by a
   * single blank.
   * The path indicated in $p_remove_dir will be removed from the
   * memorized path of each file / directory listed when this path
   * exists. By default nothing is removed (empty path '')
   * The path indicated in $p_add_dir will be added at the beginning of
   * the memorized path of each file / directory listed. However it can
   * be set to empty ''. The adding of a path is done after the removing
   * of path.
   * The path add/remove ability enables the user to prepare an archive
   * for extraction in a different path than the origin files are.
   * If a file/dir is already in the archive it will only be added at the
   * end of the archive. There is no update of the existing archived
   * file/dir. However while extracting the archive, the last file will
   * replace the first one. This results in a none optimization of the
   * archive size.
   * If a file/dir does not exist the file/dir is ignored. However an
   * error text is send to PEAR error.
   * If a file/dir is not readable the file/dir is ignored. However an
   * error text is send to PEAR error.
   *
   * @param array $p_filelist An array of filenames and directory
   *                             names, or a single string with names
   *                             separated by a single blank space.
   * @param string $p_add_dir A string which contains a path to be
   *                             added to the memorized path of each
   *                             element in the list.
   * @param string $p_remove_dir A string which contains a path to be
   *                             removed from the memorized path of
   *                             each element in the list, when
   *                             relevant.
   *
   * @return bool true on success, false on error.
   */
  public function addModify($p_filelist, $p_add_dir, $p_remove_dir = '') 
   {
    $v_result = true;

    if (!$this->_isArchive()) {
      $v_result = $this->createModify(
      $p_filelist, 
      $p_add_dir, 
      $p_remove_dir
      );
    }
    else {
      if (is_array($p_filelist)) {
        $v_list = $p_filelist;
      }
      elseif (is_string($p_filelist)) {
        $v_list = explode($this->_separator, $p_filelist);
      }
      else {
        $this->_error('Invalid file list');
        return false;
      }

      $v_result = $this->_append($v_list, $p_add_dir, $p_remove_dir);
    }

    return $v_result;
  }

  /**
   * This method add a single string as a file at the
   * end of the existing archive. If the archive does not yet exists it
   * is created.
   *
   * @param string $p_filename A string which contains the full
   *                           filename path that will be associated
   *                           with the string.
   * @param string $p_string The content of the file added in
   *                           the archive.
   * @param bool|int $p_datetime A custom date/time (unix timestamp)
   *                           for the file (optional).
   * @param array $p_params An array of optional params:
   *                               stamp => the datetime (replaces
   *                                   datetime above if it exists)
   *                               mode => the permissions on the
   *                                   file (600 by default)
   *                               type => is this a link?  See the
   *                                   tar specification for details.
   *                                   (default = regular file)
   *                               uid => the user ID of the file
   *                                   (default = 0 = root)
   *                               gid => the group ID of the file
   *                                   (default = 0 = root)
   *
   * @return bool true on success, false on error.
   */
  public function addString($p_filename, $p_string, $p_datetime = false, $p_params = array()) 
   {
    $p_stamp = @$p_params["stamp"] ? $p_params["stamp"] : ($p_datetime ? $p_datetime : time());
    $p_mode = @$p_params["mode"] ? $p_params["mode"] : 0600;
    $p_type = @$p_params["type"] ? $p_params["type"] : "";
    $p_uid = @$p_params["uid"] ? $p_params["uid"] : "";
    $p_gid = @$p_params["gid"] ? $p_params["gid"] : "";
    $v_result = true;

    if (!$this->_isArchive()) {
      if (!$this->_openWrite()) {
        return false;
      }
      $this->_close();
    }

    if (!$this->_openAppend()) {
      return false;
    }

    // Need to check the get back to the temporary file ? ....
    $v_result = $this->_addString($p_filename, $p_string, $p_datetime, $p_params);

    $this->_writeFooter();

    $this->_close();

    return $v_result;
  }

  /**
   * This method extract all the content of the archive in the directory
   * indicated by $p_path. When relevant the memorized path of the
   * files/dir can be modified by removing the $p_remove_path path at the
   * beginning of the file/dir path.
   * While extracting a file, if the directory path does not exists it is
   * created.
   * While extracting a file, if the file already exists it is replaced
   * without looking for last modification date.
   * While extracting a file, if the file already exists and is write
   * protected, the extraction is aborted.
   * While extracting a file, if a directory with the same name already
   * exists, the extraction is aborted.
   * While extracting a directory, if a file with the same name already
   * exists, the extraction is aborted.
   * While extracting a file/directory if the destination directory exist
   * and is write protected, or does not exist but can not be created,
   * the extraction is aborted.
   * If after extraction an extracted file does not show the correct
   * stored file size, the extraction is aborted.
   * When the extraction is aborted, a PEAR error text is set and false
   * is returned. However the result can be a partial extraction that may
   * need to be manually cleaned.
   *
   * @param string $p_path The path of the directory where the
   *                               files/dir need to by extracted.
   * @param string $p_remove_path Part of the memorized path that can be
   *                               removed if present at the beginning of
   *                               the file/dir path.
   * @param boolean $p_preserve Preserve user/group ownership of files
   * @param boolean $p_symlinks Allow symlinks.
   *
   * @return boolean true on success, false on error.
   * @see    extractList()
   */
  public function extractModify($p_path, $p_remove_path, $p_preserve = false, $p_symlinks = true) 
   {
    $v_result = true;
    $v_list_detail = array();

    if ($v_result = $this->_openRead()) {
      $v_result = $this->_extractList(
      $p_path, 
      $v_list_detail, 
      "complete", 
      0, 
      $p_remove_path, 
      $p_preserve, 
      $p_symlinks
      );
      $this->_close();
    }

    return $v_result;
  }

  /**
   * This method extract from the archive one file identified by $p_filename.
   * The return value is a string with the file content, or NULL on error.
   *
   * @param string $p_filename The path of the file to extract in a string.
   *
   * @return a string with the file content or NULL.
   */
  public function extractInString($p_filename) 
   {
    if ($this->_openRead()) {
      $v_result = $this->_extractInString($p_filename);
      $this->_close();
    }
    else {
      $v_result = null;
    }

    return $v_result;
  }

  /**
   * This method extract from the archive only the files indicated in the
   * $p_filelist. These files are extracted in the current directory or
   * in the directory indicated by the optional $p_path parameter.
   * If indicated the $p_remove_path can be used in the same way as it is
   * used in extractModify() method.
   *
   * @param array $p_filelist An array of filenames and directory names,
   *                               or a single string with names separated
   *                               by a single blank space.
   * @param string $p_path The path of the directory where the
   *                               files/dir need to by extracted.
   * @param string $p_remove_path Part of the memorized path that can be
   *                               removed if present at the beginning of
   *                               the file/dir path.
   * @param boolean $p_preserve Preserve user/group ownership of files
   * @param boolean $p_symlinks Allow symlinks.
   *
   * @return bool true on success, false on error.
   * @see    extractModify()
   */
  public function extractList($p_filelist, $p_path = '', $p_remove_path = '', $p_preserve = false, $p_symlinks = true) 
   {
    $v_result = true;
    $v_list_detail = array();

    if (is_array($p_filelist)) {
      $v_list = $p_filelist;
    }
    elseif (is_string($p_filelist)) {
      $v_list = explode($this->_separator, $p_filelist);
    }
    else {
      $this->_error('Invalid string list');
      return false;
    }

    if ($v_result = $this->_openRead()) {
      $v_result = $this->_extractList(
      $p_path, 
      $v_list_detail, 
      "partial", 
      $v_list, 
      $p_remove_path, 
      $p_preserve, 
      $p_symlinks
      );
      $this->_close();
    }

    return $v_result;
  }

  /**
   * This method set specific attributes of the archive. It uses a variable
   * list of parameters, in the format attribute code + attribute values :
   * $arch->setAttribute(ARCHIVE_TAR_ATT_SEPARATOR, ',');
   *
   * @return bool true on success, false on error.
   */
  public function setAttribute() 
   {
    $v_result = true;

    // ----- Get the number of variable list of arguments
    if (($v_size = func_num_args()) == 0) {
      return true;
    }

    // ----- Get the arguments
    $v_att_list = func_get_args();

    // ----- Read the attributes
    $i = 0;
    while ($i < $v_size) {

      // ----- Look for next option
      switch ($v_att_list[$i]) {
        // ----- Look for options that request a string value
        case ARCHIVE_TAR_ATT_SEPARATOR:
          // ----- Check the number of parameters
          if (($i + 1) >= $v_size) {
            $this->_error(
            'Invalid number of parameters for '
              . 'attribute ARCHIVE_TAR_ATT_SEPARATOR'
              );
            return false;
          }

          // ----- Get the value
          $this->_separator = $v_att_list[$i + 1];
          $i++;
          break;

        default :
          $this->_error('Unknown attribute code ' . $v_att_list[$i] . '');
          return false;
      }

      // ----- Next attribute
      $i++;
    }

    return $v_result;
  }

  /**
   * This method sets the regular expression for ignoring files and directories
   * at import, for example:
   * $arch->setIgnoreRegexp("#CVS|\.svn#");
   *
   * @param string $regexp regular expression defining which files or directories to ignore
   */
  public function setIgnoreRegexp($regexp) 
   {
    $this->_ignore_regexp = $regexp;
  }

  /**
   * This method sets the regular expression for ignoring all files and directories
   * matching the filenames in the array list at import, for example:
   * $arch->setIgnoreList(array('CVS', '.svn', 'bin/tool'));
   *
   * @param array $list a list of file or directory names to ignore
   *
   * @access public
   */
  public function setIgnoreList($list) 
   {
    $list = str_replace(array('#', '.', '^', '$'), array('\#', '\.', '\^', '\$'), $list);
    $regexp = '#/' . join('$|/', $list) . '#';
    $this->setIgnoreRegexp($regexp);
  }

  /**
   * @param string $p_message
   */
  public function _error($p_message) 
   {
    // Backdrop change $this->error_object = $this->raiseError($p_message).
    throw new Exception($p_message);
  }

  /**
   * @param string $p_message
   */
  public function _warning($p_message) 
   {
    // Backdrop change $this->error_object = $this->raiseError($p_message).
    throw new Exception($p_message);
  }

  /**
   * @param string $p_filename
   * @return bool
   */
  public function _isArchive($p_filename = null) 
   {
    if ($p_filename == null) {
      $p_filename = $this->_tarname;
    }
    clearstatcache();
    return @is_file($p_filename) && !@is_link($p_filename);
  }

  /**
   * @return bool
   */
  public function _openWrite() 
   {
    if ($this->_compress_type == 'gz' && function_exists('gzopen')) {
      $this->_file = @gzopen($this->_tarname, "wb9");
    }
    else {
      if ($this->_compress_type == 'bz2' && function_exists('bzopen')) {
        $this->_file = @bzopen($this->_tarname, "w");
      }
      else {
        if ($this->_compress_type == 'lzma2' && function_exists('xzopen')) {
          $this->_file = @xzopen($this->_tarname, 'w');
        }
        else {
          if ($this->_compress_type == 'none') {
            $this->_file = @fopen($this->_tarname, "wb");
          }
          else {
            $this->_error(
            'Unknown or missing compression type ('
              . $this->_compress_type . ')'
              );
            return false;
          }
        }
      }
    }

    if ($this->_file == 0) {
      $this->_error(
      'Unable to open in write mode \''
        . $this->_tarname . '\''
        );
      return false;
    }

    return true;
  }

  /**
   * @return bool
   */
  public function _openRead() 
   {
    if (strtolower(substr($this->_tarname, 0, 7)) == 'http://') {

      // ----- Look if a local copy need to be done
      if ($this->_temp_tarname == '') {
        $this->_temp_tarname = uniqid('tar') . '.tmp';
        if (!$v_file_from = @fopen($this->_tarname, 'rb')) {
          $this->_error(
          'Unable to open in read mode \''
            . $this->_tarname . '\''
            );
          $this->_temp_tarname = '';
          return false;
        }
        if (!$v_file_to = @fopen($this->_temp_tarname, 'wb')) {
          $this->_error(
          'Unable to open in write mode \''
            . $this->_temp_tarname . '\''
            );
          $this->_temp_tarname = '';
          return false;
        }
        while ($v_data = @fread($v_file_from, 1024)) {
          @fwrite($v_file_to, $v_data);
        }
        @fclose($v_file_from);
        @fclose($v_file_to);
      }

      // ----- File to open if the local copy
      $v_filename = $this->_temp_tarname;
    }
    else {
      // ----- File to open if the normal Tar file

      $v_filename = $this->_tarname;
    }

    if ($this->_compress_type == 'gz' && function_exists('gzopen')) {
      $this->_file = @gzopen($v_filename, "rb");
    }
    else {
      if ($this->_compress_type == 'bz2' && function_exists('bzopen')) {
        $this->_file = @bzopen($v_filename, "r");
      }
      else {
        if ($this->_compress_type == 'lzma2' && function_exists('xzopen')) {
          $this->_file = @xzopen($v_filename, "r");
        }
        else {
          if ($this->_compress_type == 'none') {
            $this->_file = @fopen($v_filename, "rb");
          }
          else {
            $this->_error(
            'Unknown or missing compression type ('
              . $this->_compress_type . ')'
              );
            return false;
          }
        }
      }
    }

    if ($this->_file == 0) {
      $this->_error('Unable to open in read mode \'' . $v_filename . '\'');
      return false;
    }

    return true;
  }

  /**
   * @return bool
   */
  public function _openReadWrite() 
   {
    if ($this->_compress_type == 'gz') {
      $this->_file = @gzopen($this->_tarname, "r+b");
    }
    else {
      if ($this->_compress_type == 'bz2') {
        $this->_error(
        'Unable to open bz2 in read/write mode \''
          . $this->_tarname . '\' (limitation of bz2 extension)'
          );
        return false;
      }
      else {
        if ($this->_compress_type == 'lzma2') {
          $this->_error(
          'Unable to open lzma2 in read/write mode \''
            . $this->_tarname . '\' (limitation of lzma2 extension)'
            );
          return false;
        }
        else {
          if ($this->_compress_type == 'none') {
            $this->_file = @fopen($this->_tarname, "r+b");
          }
          else {
            $this->_error(
            'Unknown or missing compression type ('
              . $this->_compress_type . ')'
              );
            return false;
          }
        }
      }
    }

    if ($this->_file == 0) {
      $this->_error(
      'Unable to open in read/write mode \''
        . $this->_tarname . '\''
        );
      return false;
    }

    return true;
  }

  /**
   * @return bool
   */
  public function _close() 
   {
    //if (isset($this->_file)) {
    if (is_resource($this->_file)) {
      if ($this->_compress_type == 'gz') {
        @gzclose($this->_file);
      }
      else {
        if ($this->_compress_type == 'bz2') {
          @bzclose($this->_file);
        }
        else {
          if ($this->_compress_type == 'lzma2') {
            @xzclose($this->_file);
          }
          else {
            if ($this->_compress_type == 'none') {
              @fclose($this->_file);
            }
            else {
              $this->_error(
              'Unknown or missing compression type ('
                . $this->_compress_type . ')'
                );
            }
          }
        }
      }

      $this->_file = 0;
    }

    // ----- Look if a local copy need to be erase
    // Note that it might be interesting to keep the url for a time : ToDo
    if ($this->_temp_tarname != '') {
      @backdrop_unlink($this->_temp_tarname);
      $this->_temp_tarname = '';
    }

    return true;
  }

  /**
   * @return bool
   */
  public function _cleanFile() 
   {
    $this->_close();

    // ----- Look for a local copy
    if ($this->_temp_tarname != '') {
      // ----- Remove the local copy but not the remote tarname
      @backdrop_unlink($this->_temp_tarname);
      $this->_temp_tarname = '';
    }
    else {
      // ----- Remove the local tarname file
      @backdrop_unlink($this->_tarname);
    }
    $this->_tarname = '';

    return true;
  }

  /**
   * @param mixed $p_binary_data
   * @param integer $p_len
   * @return bool
   */
  public function _writeBlock($p_binary_data, $p_len = null) 
   {
    if (is_resource($this->_file)) {
      if ($p_len === null) {
        if ($this->_compress_type == 'gz') {
          @gzputs($this->_file, $p_binary_data);
        }
        else {
          if ($this->_compress_type == 'bz2') {
            @bzwrite($this->_file, $p_binary_data);
          }
          else {
            if ($this->_compress_type == 'lzma2') {
              @xzwrite($this->_file, $p_binary_data);
            }
            else {
              if ($this->_compress_type == 'none') {
                @fputs($this->_file, $p_binary_data);
              }
              else {
                $this->_error(
                'Unknown or missing compression type ('
                  . $this->_compress_type . ')'
                  );
              }
            }
          }
        }
      }
      else {
        if ($this->_compress_type == 'gz') {
          @gzputs($this->_file, $p_binary_data, $p_len);
        }
        else {
          if ($this->_compress_type == 'bz2') {
            @bzwrite($this->_file, $p_binary_data, $p_len);
          }
          else {
            if ($this->_compress_type == 'lzma2') {
              @xzwrite($this->_file, $p_binary_data, $p_len);
            }
            else {
              if ($this->_compress_type == 'none') {
                @fputs($this->_file, $p_binary_data, $p_len);
              }
              else {
                $this->_error(
                'Unknown or missing compression type ('
                  . $this->_compress_type . ')'
                  );
              }
            }
          }
        }
      }
    }
    return true;
  }

  /**
   * @return null|string
   */
  public function _readBlock() 
   {
    $v_block = null;
    if (is_resource($this->_file)) {
      if ($this->_compress_type == 'gz') {
        $v_block = @gzread($this->_file, 512);
      }
      else {
        if ($this->_compress_type == 'bz2') {
          $v_block = @bzread($this->_file, 512);
        }
        else {
          if ($this->_compress_type == 'lzma2') {
            $v_block = @xzread($this->_file, 512);
          }
          else {
            if ($this->_compress_type == 'none') {
              $v_block = @fread($this->_file, 512);
            }
            else {
              $this->_error(
              'Unknown or missing compression type ('
                . $this->_compress_type . ')'
                );
            }
          }
        }
      }
    }
    return $v_block;
  }

  /**
   * @param null $p_len
   * @return bool
   */
  public function _jumpBlock($p_len = null) 
   {
    if (is_resource($this->_file)) {
      if ($p_len === null) {
        $p_len = 1;
      }

      if ($this->_compress_type == 'gz') {
        @gzseek($this->_file, gztell($this->_file) + ($p_len * 512));
      }
      else {
        if ($this->_compress_type == 'bz2') {
          // ----- Replace missing bztell() and bzseek()
          for ($i = 0; $i < $p_len; $i++) {
            $this->_readBlock();
          }
        }
        else {
          if ($this->_compress_type == 'lzma2') {
            // ----- Replace missing xztell() and xzseek()
            for ($i = 0; $i < $p_len; $i++) {
              $this->_readBlock();
            }
          }
          else {
            if ($this->_compress_type == 'none') {
              @fseek($this->_file, $p_len * 512, SEEK_CUR);
            }
            else {
              $this->_error(
              'Unknown or missing compression type ('
                . $this->_compress_type . ')'
                );
            }
          }
        }
      }
    }
    return true;
  }

  /**
   * @return bool
   */
  public function _writeFooter() 
   {
    if (is_resource($this->_file)) {
      // ----- Write the last 0 filled block for end of archive
      $v_binary_data = pack('a1024', '');
      $this->_writeBlock($v_binary_data);
    }
    return true;
  }

  /**
   * @param array $p_list
   * @param string $p_add_dir
   * @param string $p_remove_dir
   * @return bool
   */
  public function _addList($p_list, $p_add_dir, $p_remove_dir) 
   {
    $v_result = true;
    $v_header = array();

    // ----- Remove potential windows directory separator
    $p_add_dir = $this->_translateWinPath($p_add_dir);
    $p_remove_dir = $this->_translateWinPath($p_remove_dir, false);

    if (!$this->_file) {
      $this->_error('Invalid file descriptor');
      return false;
    }

    if (sizeof($p_list) == 0) {
      return true;
    }

    foreach ($p_list as $v_filename) {
      if (!$v_result) {
        break;
      }

      // ----- Skip the current tar name
      if ($v_filename == $this->_tarname) {
        continue;
      }

      if ($v_filename == '') {
        continue;
      }

      // ----- ignore files and directories matching the ignore regular expression
      if ($this->_ignore_regexp && preg_match($this->_ignore_regexp, '/' . $v_filename)) {
        $this->_warning("File '$v_filename' ignored");
        continue;
      }

      if (!file_exists($v_filename) && !is_link($v_filename)) {
        $this->_warning("File '$v_filename' does not exist");
        continue;
      }

      // ----- Add the file or directory header
      if (!$this->_addFile($v_filename, $v_header, $p_add_dir, $p_remove_dir)) {
        return false;
      }

      if (@is_dir($v_filename) && !@is_link($v_filename)) {
        if (!($p_hdir = opendir($v_filename))) {
          $this->_warning("Directory '$v_filename' can not be read");
          continue;
        }
        while (false !== ($p_hitem = readdir($p_hdir))) {
          if (($p_hitem != '.') && ($p_hitem != '..')) {
            if ($v_filename != ".") {
              $p_temp_list[0] = $v_filename . '/' . $p_hitem;
            }
            else {
              $p_temp_list[0] = $p_hitem;
            }

            $v_result = $this->_addList(
            $p_temp_list, 
            $p_add_dir, 
            $p_remove_dir
            );
          }
        }

        unset($p_temp_list);
        unset($p_hdir);
        unset($p_hitem);
      }
    }

    return $v_result;
  }

  /**
   * @param string $p_filename
   * @param mixed $p_header
   * @param string $p_add_dir
   * @param string $p_remove_dir
   * @param null $v_stored_filename
   * @return bool
   */
  public function _addFile($p_filename, &$p_header, $p_add_dir, $p_remove_dir, $v_stored_filename = null) 
   {
    if (!$this->_file) {
      $this->_error('Invalid file descriptor');
      return false;
    }

    if ($p_filename == '') {
      $this->_error('Invalid file name');
      return false;
    }

    if (is_null($v_stored_filename)) {
      // ----- Calculate the stored filename
      $p_filename = $this->_translateWinPath($p_filename, false);
      $v_stored_filename = $p_filename;

      if (strcmp($p_filename, $p_remove_dir) == 0) {
        return true;
      }

      if ($p_remove_dir != '') {
        if (substr($p_remove_dir, -1) != '/') {
          $p_remove_dir .= '/';
        }

        if (substr($p_filename, 0, strlen($p_remove_dir)) == $p_remove_dir) {
          $v_stored_filename = substr($p_filename, strlen($p_remove_dir));
        }
      }

      $v_stored_filename = $this->_translateWinPath($v_stored_filename);
      if ($p_add_dir != '') {
        if (substr($p_add_dir, -1) == '/') {
          $v_stored_filename = $p_add_dir . $v_stored_filename;
        }
        else {
          $v_stored_filename = $p_add_dir . '/' . $v_stored_filename;
        }
      }

      $v_stored_filename = $this->_pathReduction($v_stored_filename);
    }

    if ($this->_isArchive($p_filename)) {
      if (($v_file = @fopen($p_filename, "rb")) == 0) {
        $this->_warning(
        "Unable to open file '" . $p_filename
          . "' in binary read mode"
          );
        return true;
      }

      if (!$this->_writeHeader($p_filename, $v_stored_filename)) {
        return false;
      }

      while (($v_buffer = fread($v_file, $this->buffer_length)) != '') {
        $buffer_length = strlen("$v_buffer");
        if ($buffer_length != $this->buffer_length) {
          $pack_size = ((int) ($buffer_length / 512) + ($buffer_length % 512 !== 0 ? 1 : 0)) * 512;
          $pack_format = sprintf('a%d', $pack_size);
        }
        else {
          $pack_format = sprintf('a%d', $this->buffer_length);
        }
        $v_binary_data = pack($pack_format, "$v_buffer");
        $this->_writeBlock($v_binary_data);
      }

      fclose($v_file);
    }
    else {
      // ----- Only header for dir
      if (!$this->_writeHeader($p_filename, $v_stored_filename)) {
        return false;
      }
    }

    return true;
  }

  /**
   * @param string $p_filename
   * @param string $p_string
   * @param bool $p_datetime
   * @param array $p_params
   * @return bool
   */
  public function _addString($p_filename, $p_string, $p_datetime = false, $p_params = array()) 
   {
    $p_stamp = @$p_params["stamp"] ? $p_params["stamp"] : ($p_datetime ? $p_datetime : time());
    $p_mode = @$p_params["mode"] ? $p_params["mode"] : 0600;
    $p_type = @$p_params["type"] ? $p_params["type"] : "";
    $p_uid = @$p_params["uid"] ? $p_params["uid"] : 0;
    $p_gid = @$p_params["gid"] ? $p_params["gid"] : 0;
    if (!$this->_file) {
      $this->_error('Invalid file descriptor');
      return false;
    }

    if ($p_filename == '') {
      $this->_error('Invalid file name');
      return false;
    }

    // ----- Calculate the stored filename
    $p_filename = $this->_translateWinPath($p_filename, false);

    // ----- If datetime is not specified, set current time
    if ($p_datetime === false) {
      $p_datetime = time();
    }

    if (!$this->_writeHeaderBlock(
    $p_filename, 
    strlen($p_string), 
    $p_stamp, 
    $p_mode, 
    $p_type, 
    $p_uid, 
    $p_gid
    )
    ) {
      return false;
    }

    $i = 0;
    while (($v_buffer = substr($p_string, (($i++) * 512), 512)) != '') {
      $v_binary_data = pack("a512", $v_buffer);
      $this->_writeBlock($v_binary_data);
    }

    return true;
  }

  /**
   * @param string $p_filename
   * @param string $p_stored_filename
   * @return bool
   */
  public function _writeHeader($p_filename, $p_stored_filename) 
   {
    if ($p_stored_filename == '') {
      $p_stored_filename = $p_filename;
    }

    $v_reduced_filename = $this->_pathReduction($p_stored_filename);

    if (strlen($v_reduced_filename) > 99) {
      if (!$this->_writeLongHeader($v_reduced_filename, false)) {
        return false;
      }
    }

    $v_linkname = '';
    if (@is_link($p_filename)) {
      $v_linkname = readlink($p_filename);
    }

    if (strlen($v_linkname) > 99) {
      if (!$this->_writeLongHeader($v_linkname, true)) {
        return false;
      }
    }

    $v_info = lstat($p_filename);
    $v_uid = sprintf("%07s", DecOct($v_info[4]));
    $v_gid = sprintf("%07s", DecOct($v_info[5]));
    $v_perms = sprintf("%07s", DecOct($v_info['mode'] & 000777));
    $v_mtime = sprintf("%011s", DecOct($v_info['mtime']));

    if (@is_link($p_filename)) {
      $v_typeflag = '2';
      $v_size = sprintf("%011s", DecOct(0));
    }
    elseif (@is_dir($p_filename)) {
      $v_typeflag = "5";
      $v_size = sprintf("%011s", DecOct(0));
    }
    else {
      $v_typeflag = '0';
      clearstatcache();
      $v_size = sprintf("%011s", DecOct($v_info['size']));
    }

    $v_magic = 'ustar ';
    $v_version = ' ';
    $v_uname = '';
    $v_gname = '';

    if (function_exists('posix_getpwuid')) {
      $userinfo = posix_getpwuid($v_info[4]);
      $groupinfo = posix_getgrgid($v_info[5]);

      if (isset($userinfo['name'])) {
        $v_uname = $userinfo['name'];
      }

      if (isset($groupinfo['name'])) {
        $v_gname = $groupinfo['name'];
      }
    }

    $v_devmajor = '';

    $v_devminor = '';

    $v_prefix = '';

    $v_binary_data_first = pack(
    "a100a8a8a8a12a12", 
    $v_reduced_filename, 
    $v_perms, 
    $v_uid, 
    $v_gid, 
    $v_size, 
    $v_mtime
    );
    $v_binary_data_last = pack(
    "a1a100a6a2a32a32a8a8a155a12", 
    $v_typeflag, 
    $v_linkname, 
    $v_magic, 
    $v_version, 
    $v_uname, 
    $v_gname, 
    $v_devmajor, 
    $v_devminor, 
    $v_prefix, 
    ''
    );

    // ----- Calculate the checksum
    $v_checksum = 0;
    // ..... First part of the header
    for ($i = 0; $i < 148; $i++) {
      $v_checksum += ord(substr($v_binary_data_first, $i, 1));
    }
    // ..... Ignore the checksum value and replace it by ' ' (space)
    for ($i = 148; $i < 156; $i++) {
      $v_checksum += ord(' ');
    }
    // ..... Last part of the header
    for ($i = 156, $j = 0; $i < 512; $i++, $j++) {
      $v_checksum += ord(substr($v_binary_data_last, $j, 1));
    }

    // ----- Write the first 148 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_first, 148);

    // ----- Write the calculated checksum
    $v_checksum = sprintf("%06s\0 ", DecOct($v_checksum));
    $v_binary_data = pack("a8", $v_checksum);
    $this->_writeBlock($v_binary_data, 8);

    // ----- Write the last 356 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_last, 356);

    return true;
  }

  /**
   * @param string $p_filename
   * @param int $p_size
   * @param int $p_mtime
   * @param int $p_perms
   * @param string $p_type
   * @param int $p_uid
   * @param int $p_gid
   * @return bool
   */
  public function _writeHeaderBlock(
  $p_filename, 
  $p_size, 
  $p_mtime = 0, 
  $p_perms = 0, 
  $p_type = '', 
  $p_uid = 0, 
  $p_gid = 0
  ) 
   {
    $p_filename = $this->_pathReduction($p_filename);

    if (strlen($p_filename) > 99) {
      if (!$this->_writeLongHeader($p_filename, false)) {
        return false;
      }
    }

    if ($p_type == "5") {
      $v_size = sprintf("%011s", DecOct(0));
    }
    else {
      $v_size = sprintf("%011s", DecOct($p_size));
    }

    $v_uid = sprintf("%07s", DecOct($p_uid));
    $v_gid = sprintf("%07s", DecOct($p_gid));
    $v_perms = sprintf("%07s", DecOct($p_perms & 000777));

    $v_mtime = sprintf("%11s", DecOct($p_mtime));

    $v_linkname = '';

    $v_magic = 'ustar ';

    $v_version = ' ';

    if (function_exists('posix_getpwuid')) {
      $userinfo = posix_getpwuid($p_uid);
      $groupinfo = posix_getgrgid($p_gid);

      if ($userinfo === false || $groupinfo === false) {
        $v_uname = '';
        $v_gname = '';
      }
      else {
        $v_uname = $userinfo['name'];
        $v_gname = $groupinfo['name'];
      }
    }
    else {
      $v_uname = '';
      $v_gname = '';
    }

    $v_devmajor = '';
    $v_devminor = '';
    $v_prefix = '';

    $v_binary_data_first = pack(
    "a100a8a8a8a12A12", 
    $p_filename, 
    $v_perms, 
    $v_uid, 
    $v_gid, 
    $v_size, 
    $v_mtime
    );
    $v_binary_data_last = pack(
    "a1a100a6a2a32a32a8a8a155a12", 
    $p_type, 
    $v_linkname, 
    $v_magic, 
    $v_version, 
    $v_uname, 
    $v_gname, 
    $v_devmajor, 
    $v_devminor, 
    $v_prefix, 
    ''
    );

    // ----- Calculate the checksum
    $v_checksum = 0;
    // ..... First part of the header
    for ($i = 0; $i < 148; $i++) {
      $v_checksum += ord(substr($v_binary_data_first, $i, 1));
    }
    // ..... Ignore the checksum value and replace it by ' ' (space)
    for ($i = 148; $i < 156; $i++) {
      $v_checksum += ord(' ');
    }
    // ..... Last part of the header
    for ($i = 156, $j = 0; $i < 512; $i++, $j++) {
      $v_checksum += ord(substr($v_binary_data_last, $j, 1));
    }

    // ----- Write the first 148 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_first, 148);

    // ----- Write the calculated checksum
    $v_checksum = sprintf("%06s ", DecOct($v_checksum));
    $v_binary_data = pack("a8", $v_checksum);
    $this->_writeBlock($v_binary_data, 8);

    // ----- Write the last 356 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_last, 356);

    return true;
  }

  /**
   * @param string $p_filename
   * @return bool
   */
  public function _writeLongHeader($p_filename, $is_link = false) 
   {
    $v_uid = sprintf("%07s", 0);
    $v_gid = sprintf("%07s", 0);
    $v_perms = sprintf("%07s", 0);
    $v_size = sprintf("%'011s", DecOct(strlen($p_filename)));
    $v_mtime = sprintf("%011s", 0);
    $v_typeflag = ($is_link ? 'K' : 'L');
    $v_linkname = '';
    $v_magic = 'ustar ';
    $v_version = ' ';
    $v_uname = '';
    $v_gname = '';
    $v_devmajor = '';
    $v_devminor = '';
    $v_prefix = '';

    $v_binary_data_first = pack(
    "a100a8a8a8a12a12", 
    '././@LongLink', 
    $v_perms, 
    $v_uid, 
    $v_gid, 
    $v_size, 
    $v_mtime
    );
    $v_binary_data_last = pack(
    "a1a100a6a2a32a32a8a8a155a12", 
    $v_typeflag, 
    $v_linkname, 
    $v_magic, 
    $v_version, 
    $v_uname, 
    $v_gname, 
    $v_devmajor, 
    $v_devminor, 
    $v_prefix, 
    ''
    );

    // ----- Calculate the checksum
    $v_checksum = 0;
    // ..... First part of the header
    for ($i = 0; $i < 148; $i++) {
      $v_checksum += ord(substr($v_binary_data_first, $i, 1));
    }
    // ..... Ignore the checksum value and replace it by ' ' (space)
    for ($i = 148; $i < 156; $i++) {
      $v_checksum += ord(' ');
    }
    // ..... Last part of the header
    for ($i = 156, $j = 0; $i < 512; $i++, $j++) {
      $v_checksum += ord(substr($v_binary_data_last, $j, 1));
    }

    // ----- Write the first 148 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_first, 148);

    // ----- Write the calculated checksum
    $v_checksum = sprintf("%06s\0 ", DecOct($v_checksum));
    $v_binary_data = pack("a8", $v_checksum);
    $this->_writeBlock($v_binary_data, 8);

    // ----- Write the last 356 bytes of the header in the archive
    $this->_writeBlock($v_binary_data_last, 356);

    // ----- Write the filename as content of the block
    $i = 0;
    while (($v_buffer = substr($p_filename, (($i++) * 512), 512)) != '') {
      $v_binary_data = pack("a512", "$v_buffer");
      $this->_writeBlock($v_binary_data);
    }

    return true;
  }

  /**
   * @param mixed $v_binary_data
   * @param mixed $v_header
   * @return bool
   */
  public function _readHeader($v_binary_data, &$v_header) 
   {
    if (strlen($v_binary_data) == 0) {
      $v_header['filename'] = '';
      return true;
    }

    if (strlen($v_binary_data) != 512) {
      $v_header['filename'] = '';
      $this->_error('Invalid block size : ' . strlen($v_binary_data));
      return false;
    }

    if (!is_array($v_header)) {
      $v_header = array();
    }
    // ----- Calculate the checksum
    $v_checksum = 0;
    // ..... First part of the header
    $v_binary_split = str_split($v_binary_data);
    $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 0, 148)));
    $v_checksum += array_sum(array_map('ord', array(' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',)));
    $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 156, 512)));

    $v_data = unpack($this->_fmt, $v_binary_data);

    if (strlen($v_data["prefix"]) > 0) {
      $v_data["filename"] = "$v_data[prefix]/$v_data[filename]";
    }

    // ----- Extract the checksum
    $v_data_checksum = trim($v_data['checksum']);
    if (!preg_match('/^[0-7]*$/', $v_data_checksum)) {
      $this->_error(
      'Invalid checksum for file "' . $v_data['filename']
        . '" : ' . $v_data_checksum . ' extracted'
        );
      return false;
    }

    $v_header['checksum'] = OctDec($v_data_checksum);
    if ($v_header['checksum'] != $v_checksum) {
      $v_header['filename'] = '';

      // ----- Look for last block (empty block)
      if (($v_checksum == 256) && ($v_header['checksum'] == 0)) {
        return true;
      }

      $this->_error(
      'Invalid checksum for file "' . $v_data['filename']
        . '" : ' . $v_checksum . ' calculated, '
        . $v_header['checksum'] . ' expected'
        );
      return false;
    }

    // ----- Extract the properties
    $v_header['filename'] = rtrim($v_data['filename'], "\0");
    if ($this->_isMaliciousFilename($v_header['filename'])) {
      $this->_error(
      'Malicious .tar detected, file "' . $v_header['filename'] .
        '" will not install in desired directory tree'
        );
      return false;
    }
    $v_header['mode'] = OctDec(trim($v_data['mode']));
    $v_header['uid'] = OctDec(trim($v_data['uid']));
    $v_header['gid'] = OctDec(trim($v_data['gid']));
    $v_header['size'] = $this->_tarRecToSize($v_data['size']);
    $v_header['mtime'] = OctDec(trim($v_data['mtime']));
    if (($v_header['typeflag'] = $v_data['typeflag']) == "5") {
      $v_header['size'] = 0;
    }
    $v_header['link'] = trim($v_data['link']);
    /* ----- All these fields are removed form the header because
        they do not carry interesting info
        $v_header[magic] = trim($v_data[magic]);
        $v_header[version] = trim($v_data[version]);
        $v_header[uname] = trim($v_data[uname]);
        $v_header[gname] = trim($v_data[gname]);
        $v_header[devmajor] = trim($v_data[devmajor]);
        $v_header[devminor] = trim($v_data[devminor]);
        */

    return true;
  }

  /**
   * Convert Tar record size to actual size
   *
   * @param string $tar_size
   * @return size of tar record in bytes
   */
  private function _tarRecToSize($tar_size) 
   {
    /*
     * First byte of size has a special meaning if bit 7 is set.
     *
     * Bit 7 indicates base-256 encoding if set.
     * Bit 6 is the sign bit.
     * Bits 5:0 are most significant value bits.
     */
    $ch = ord($tar_size[0]);
    if ($ch & 0x80) {
      // Full 12-bytes record is required.
      $rec_str = $tar_size . "\x00";

      $size = ($ch & 0x40) ? -1 : 0;
      $size = ($size << 6) | ($ch & 0x3f);

      for ($num_ch = 1; $num_ch < 12; ++$num_ch) {
        $size = ($size * 256) + ord($rec_str[$num_ch]);
      }

      return $size;

    }
    else {
      return OctDec(trim($tar_size));
    }
  }

  /**
   * Detect and report a malicious file name
   *
   * @param string $file
   *
   * @return bool
   */
  private function _isMaliciousFilename($file) 
   {
    if (strpos($file, '://') !== false) {
      return true;
    }
    if (strpos($file, '../') !== false || strpos($file, '..\\') !== false) {
      return true;
    }
    return false;
  }

  /**
   * @param $v_header
   * @return bool
   */
  public function _readLongHeader(&$v_header) 
   {
    $v_filename = '';
    $v_filesize = $v_header['size'];
    $n = floor($v_header['size'] / 512);
    for ($i = 0; $i < $n; $i++) {
      $v_content = $this->_readBlock();
      $v_filename .= $v_content;
    }
    if (($v_header['size'] % 512) != 0) {
      $v_content = $this->_readBlock();
      $v_filename .= $v_content;
    }

    // ----- Read the next header
    $v_binary_data = $this->_readBlock();

    if (!$this->_readHeader($v_binary_data, $v_header)) {
      return false;
    }

    $v_filename = rtrim(substr($v_filename, 0, $v_filesize), "\0");
    $v_header['filename'] = $v_filename;
    if ($this->_isMaliciousFilename($v_filename)) {
      $this->_error(
      'Malicious .tar detected, file "' . $v_filename .
        '" will not install in desired directory tree'
        );
      return false;
    }

    return true;
  }

  /**
   * This method extract from the archive one file identified by $p_filename.
   * The return value is a string with the file content, or null on error.
   *
   * @param string $p_filename The path of the file to extract in a string.
   *
   * @return a string with the file content or null.
   */
  private function _extractInString($p_filename) 
   {
    $v_result_str = "";

    while (strlen($v_binary_data = $this->_readBlock()) != 0) {
      if (!$this->_readHeader($v_binary_data, $v_header)) {
        return null;
      }

      if ($v_header['filename'] == '') {
        continue;
      }

      switch ($v_header['typeflag']) {
        case 'L':
          {              if (!$this->_readLongHeader($v_header)) {
                return null;
              }          }
      }
      break;

      case 'K':
        {            $v_link_header = $v_header;
            if (!$this->_readLongHeader($v_link_header)) {
              return null;
            }
            $v_header['link'] = $v_link_header['filename'];        }
    }
    break;
  }

  if ($v_header['filename'] == $p_filename) {
    if ($v_header['typeflag'] == "5") {
      $this->_error(
      'Unable to extract in string a directory '
        . 'entry {' . $v_header['filename'] . '}'
        );
      return null;
    }
    else {
      $n = floor($v_header['size'] / 512);
      for ($i = 0; $i < $n; $i++) {
        $v_result_str .= $this->_readBlock();
      }
      if (($v_header['size'] % 512) != 0) {
        $v_content = $this->_readBlock();
        $v_result_str .= substr(
        $v_content, 
        0, 
        ($v_header['size'] % 512)
        );
      }
      return $v_result_str;
    }
  }
  else {
    $this->_jumpBlock(ceil(($v_header['size'] / 512)));
  }
}