original_string: protected function restrict()
  	{
  		$length = strlen($this->data);
  
  		if ($length > 0)
  		{
  			$this->data[$length - 1] = chr(ord($this->data[$length - 1]) & self::$restrict[$this->size % 8]);
  		}
  
  		return $this;
  	}
code: protected function restrict()
  	{
  		$length = strlen($this->data);
  
  		if ($length > 0)
  		{
  			$this->data[$length - 1] = chr(ord($this->data[$length - 1]) & self::$restrict[$this->size % 8]);
  		}
  
  		return $this;
  	}
code_tokens: protected function restrict ( ) { $ length = strlen ( $ this -> data ) ; if ( $ length > 0 ) { $ this -> data [ $ length - 1 ] = chr ( ord ( $ this -> data [ $ length - 1 ] ) & self :: $ restrict [ $ this -> size % 8 ] ) ; } return $ this ; }
docstring: Remove useless bits for simplifying count operation.
  
  @return  BitArray  $this for chaining
  
  @since   1.2.0
docstring_tokens: Remove useless bits for simplifying count operation .