1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
// package hex implements a lower-case hex parser.
package hex
import (
"fmt"
)
const (
language = "0123456789abcdef"
)
// Serialize serializes a buffer as lower-case hex
func Serialize(buf []byte) string {
out := make([]byte, len(buf)*2)
for i, b := range buf {
offset := i * 2
out[offset] = language[b>>4]
out[offset+1] = language[b&0x0f]
}
return string(out)
}
// Deserialize tries to deserialize a lower-case hex string
func Deserialize(str string) ([]byte, error) {
if len(str)%2 != 0 {
return nil, fmt.Errorf("hex: string must have even length")
}
buf := make([]byte, len(str)/2)
for i := 0; i < len(buf); i++ {
offset := i * 2
first, ok := deserializeOne(str[offset])
if !ok {
return nil, fmt.Errorf("hex: invalid character at index %d: %d", i, first)
}
second, ok := deserializeOne(str[offset+1])
if !ok {
return nil, fmt.Errorf("hex: invalid character at index %d: %d", i, second)
}
buf[i] = first << 4
buf[i] = buf[i] | second
}
return buf, nil
}
func deserializeOne(b byte) (byte, bool) {
if b >= '0' && b <= '9' {
return b - '0', true
}
if b >= 'a' && b <= 'f' {
return b - 'a' + 10, true
}
return 0, false
}
|
