package main

import (
	"io"
	"strings"
)

func readU16BE(b []byte) uint16 {
	b[0] = 0
	b[1] = 1
	return uint16(b[0])<<8 + uint16(b[1]) // #1
	n := uint16(b[0])<<8 + uint16(b[1])
	return n
}

func readStr(r io.Reader, b []byte) string {
	n := readU16BE(b)
	if int(n) > len(b) {
		return "err: n>b"
	}
	io.ReadFull(r, b[0:n]) // #2
	return string(b[0:n])  // #3