original_string: protected function _getFileData($id, $field = null)
      {
          if (!isset($this->_files[$id - 1])) {
              /**
               * @see Zend_Mail_Storage_Exception
               */
              // require_once 'Zend/Mail/Storage/Exception.php';
              throw new Zend_Mail_Storage_Exception('id does not exist');
          }
  
          if (!$field) {
              return $this->_files[$id - 1];
          }
  
          if (!isset($this->_files[$id - 1][$field])) {
              /**
               * @see Zend_Mail_Storage_Exception
               */
              // require_once 'Zend/Mail/Storage/Exception.php';
              throw new Zend_Mail_Storage_Exception('field does not exist');
          }
  
          return $this->_files[$id - 1][$field];
      }
code: protected function _getFileData($id, $field = null)
      {
          if (!isset($this->_files[$id - 1])) {
              /**
               * @see Zend_Mail_Storage_Exception
               */
              // require_once 'Zend/Mail/Storage/Exception.php';
              throw new Zend_Mail_Storage_Exception('id does not exist');
          }
  
          if (!$field) {
              return $this->_files[$id - 1];
          }
  
          if (!isset($this->_files[$id - 1][$field])) {
              /**
               * @see Zend_Mail_Storage_Exception
               */
              // require_once 'Zend/Mail/Storage/Exception.php';
              throw new Zend_Mail_Storage_Exception('field does not exist');
          }
  
          return $this->_files[$id - 1][$field];
      }
code_tokens: protected function _getFileData ( $ id , $ field = null ) { if ( ! isset ( $ this -> _files [ $ id - 1 ] ) ) { /**
               * @see Zend_Mail_Storage_Exception
               */ // require_once 'Zend/Mail/Storage/Exception.php'; throw new Zend_Mail_Storage_Exception ( 'id does not exist' ) ; } if ( ! $ field ) { return $ this -> _files [ $ id - 1 ] ; } if ( ! isset ( $ this -> _files [ $ id - 1 ] [ $ field ] ) ) { /**
               * @see Zend_Mail_Storage_Exception
               */ // require_once 'Zend/Mail/Storage/Exception.php'; throw new Zend_Mail_Storage_Exception ( 'field does not exist' ) ; } return $ this -> _files [ $ id - 1 ] [ $ field ] ; }
docstring: Get one or all fields from file structure. Also checks if message is valid
  
  @param  int         $id    message number
  @param  string|null $field wanted field
  @return string|array wanted field or all fields as array
  @throws Zend_Mail_Storage_Exception
docstring_tokens: Get one or all fields from file structure . Also checks if message is valid