flag.Usage()
		os.Exit(1)
	}
	var err error
	switch mode := flag.Arg(0); mode {
	case "size":
		err = printSizeStats(os.Stdin)
	default:
		log.Printf("unknown mode %q", mode)
		flag.Usage()
		os.Exit(1)
	}
	if err != nil {
		log.Fatalf("error: %v", err)
		os.Exit(1)
	}
}

func printSizeStats(r io.Reader) error {
	cr := countingReader{Reader: r}
	tr, err := raw.NewReader(&cr)
	if err != nil {