go rot13

rot13.go

package main

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

type rot13Reader struct {
	r io.Reader
}

func (r13reader rot13Reader) Read(bytes []byte) (int, error) {
	n, err := r13reader.r.Read(bytes)
	if err != nil {
		if err == io.EOF {
			return n, io.EOF
		} else {
			panic("something went horribly wrong")
		}
	}
	for n, c := range bytes {
		if (c > 77 && c < 91) || c > 109 {
			c -= 13
		} else if c > 64 || c > 96 {
			c += 13
		}
		bytes[n] = c
	}
	return n, nil
}

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