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A Tour of Go, exercise rot13Reader
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| package main | |
| import ( | |
| "io" | |
| "os" | |
| "strings" | |
| ) | |
| type rot13Reader struct { | |
| r io.Reader | |
| } | |
| func (rot *rot13Reader) Read(p []byte) (n int, err error) { | |
| n, err = rot.r.Read(p) | |
| for i := 0; i < len(p); i++ { | |
| if p[i] >= 'A' && p[i] < 'Z' { | |
| p[i] = 65 + (((p[i] - 65) + 13) % 26) | |
| } else if p[i] >= 'a' && p[i] <= 'z' { | |
| p[i] = 97 + (((p[i] - 97) + 13) % 26) | |
| } | |
| } | |
| return | |
| } | |
| func main() { | |
| s := strings.NewReader("Lbh penpxrq gur pbqr!") | |
| r := rot13Reader{s} | |
| io.Copy(os.Stdout, &r) | |
| } |
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func (rot *rot13Reader) Read(p []byte) (n int, err error) {
n, err = rot.r.Read(p)
if err != nil {
return n, err
}
for i := range p {
switch {
case p[i] >= 'A' && p[i] <= 'M':
p[i] += 13
case p[i] >= 'N' && p[i] <= 'Z':
p[i] -= 13
case p[i] >= 'a' && p[i] <= 'm':
p[i] += 13
case p[i] >= 'n' && p[i] <= 'z':
p[i] -= 13
}
}
return
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
)
const input = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
const output = "NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm"
type rot13Reader struct {
r io.Reader
}
func (r *rot13Reader) Read(b []byte) (int, error) {
n, err := r.r.Read(b)
if err != nil {
return n, err
}
for i := range b {
inputIndex := strings.Index(input, string(b[i]))
if inputIndex < 0 {
continue
}
b[i] = output[inputIndex]
}
return n, nil
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func (r rot13Reader) Read(bytes []byte) (int, error) {
n, err := r.r.Read(bytes)
for i := 0; i < n; i++ {
byte := bytes[i]
if byte >= 'A' && byte <= 'M' {
bytes[i] += 13
}
if byte >= 'N' && byte <= 'Z' {
bytes[i] -= 13
}
if byte >= 'a' && byte <= 'm' {
bytes[i] += 13
}
if byte >= 'n' && byte <= 'z' {
bytes[i] -= 13
}
}
return n, err
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, r)
}
func (rot rot13Reader) Read(b []byte) (int, error) {
v, err := rot.r.Read(b)
for i := 0; i < v; i++ {
b[i] = rot13(string(b[i]))[0]
}
if err != nil {
return 0, err
}
return v, nil
}
func rot13(s string) (string) {
s = strings.ToUpper(s)
for i := 0; i < len(s); i++ {
if string(s[i]) < "M" {
return string( s[i] + 13)
}
if string(s[i]) > "M" {
return string( s[i] - 13)
}
}
return s;
}
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func (rot *rot13Reader) Read(p []byte) (n int, err error) {
n, err = rot.r.Read(p)
for i := 0; i < len(p); i++ {
if p[i] >= 'A' && p[i] < 'Z' {
p[i] = 65 + (((p[i] - 65) + 13) % 26)
} else if p[i] >= 'a' && p[i] <= 'z' {
p[i] = 97 + (((p[i] - 98) + 13) % 26)
}
}
return
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func (r *rot13Reader) Read(b []byte) (int, error) {
if n, err := r.r.Read(b); err != nil {
return n, err
}
for i, v := range b {
if v > 64 && v < 91 {
b[i] = (v - 65 + 13) % 26 + 65
} else if v > 96 && v < 123 {
b[i] = (v - 97 + 13) % 26 + 97
}
}
return len(b), nil
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func (rot13 rot13Reader) Read(out []byte) (int, error) {
n, err := rot13.r.Read(out)
if err != nil {
return n, err
}
for i := 0; i < len(out); i++ {
if out[i] >= 'A' && out[i] <= 'Z' {
out[i] = 'A' + (((out[i] - 'A') + 13) % 26)
}
if out[i] >= 'a' && out[i] <= 'z' {
out[i] = 'a' + (((out[i] - 'a') + 13) % 26)
}
}
return n, nil
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}I wanted to do compact & efficient :)
package main
import (
"io"
"os"
"strings"
)
type rot13Reader struct {
r io.Reader
}
func rot13(c byte) byte {
c += 13
if (c > 'Z' && c < 'a') || c > 'z' {
c -= 26
}
return c
}
func (rot *rot13Reader) Read(b []byte) (int, error) {
message := make([]byte, len(b))
n, err := rot.r.Read(message)
for i := range message {
b[i] = rot13(message[i])
}
return n, err
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
package main
import (
"io"
"os"
"strings"
"unicode"
)
type rot13Reader struct {
r io.Reader
}
const (
lowerMap = "nopqrstuvwxyzabcdefghijklm"
upperMap = "NOPQRSTUVWXYZABCDEFGHIJKLM"
)
func rotateBytes(bytes []byte) {
for i := range bytes {
if unicode.IsLower(rune(bytes[i])) {
bytes[i] = lowerMap[bytes[i]-'a']
} else if unicode.IsUpper(rune(bytes[i])) {
bytes[i] = upperMap[bytes[i]-'A']
}
}
}
func (rot13 *rot13Reader) Read(bytes []byte) (int, error) {
n, err := rot13.r.Read(bytes)
rotateBytes(bytes)
return n, err
}
func main() {
s := strings.NewReader("Lbh penpxrq gur pbqr!")
r := rot13Reader{s}
io.Copy(os.Stdout, &r)
}
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