Golang tour #60

go_tour_60.go

package main

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

type rot13Reader struct {
    r io.Reader
}

func (r rot13Reader) Read(p []byte) (int, error){   
    n, err := r.r.Read(p)
    
    if err != nil || n == 0 {
    	return 0, io.EOF
    }
    for i,c := range p {
    	switch {
        	case (c >= 'n' && c <= 'z') || (c >= 'N' && c <= 'Z'):
        		p[i] -= 13   
        	case (c >= 'a' && c < 'n') || (c >= 'A' && c < 'N'):
        		p[i] += 13   
        } 
    }

    return n, nil
}


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