Exercise: rot13Reader - A Tour of Go

exercise-rot-reader.go

package main

import (
	"io"
	"os"
	"strings"
)

type rot13Reader struct {
	r io.Reader
}

func (rot rot13Reader) Read(b []byte) (int, error) {

	n, err := rot.r.Read(b)
	for i := range b {
		if b[i] >= 0x41 && b[i] <= 0x5a {
			b[i] = byte((int(b[i]) - 0x41 + 13 )% 26 + 0x41)
		} else if b[i] >= 0x61 && b[i] <= 0x7a {
			b[i] = byte((int(b[i]) - 0x61 + 13 )% 26 + 0x61)
		}
	}

	return n, err
}

func main() {
	//Lbh penpxrq gur pbqr!
	s := strings.NewReader("You cracked the code!")
	r := rot13Reader{s}
	io.Copy(os.Stdout, &r)
}