| 64 | } |
| 65 | |
| 66 | func decode(s string) ([]byte, error) { |
| 67 | if s == "" { |
| 68 | return nil, nil |
| 69 | } |
| 70 | |
| 71 | sl := len(s) |
| 72 | |
| 73 | is := make([]int, sl) |
| 74 | for i := 0; i < sl/3; i++ { |
| 75 | b, ok := m2[s[i*3:i*3+3]] |
| 76 | if !ok { |
| 77 | return nil, errors.New("invalid string, cur: " + strconv.Itoa(i)) |
| 78 | } |
| 79 | copy(is[i*3:i*3+3], b[:]) |
| 80 | } |
| 81 | |
| 82 | buf := make([]byte, sl/8) |
| 83 | for i := 0; i < sl/8; i++ { |
| 84 | buf[i] = b8ToByte(is[i*8 : i*8+8]) |
| 85 | } |
| 86 | |
| 87 | return buf, nil |
| 88 | } |
| 89 | |
| 90 | func b8ToByte(b []int) byte { |
| 91 | return byte(b[0]<<7 + b[1]<<6 + b[2]<<5 + b[3]<<4 + b[4]<<3 + b[5]<<2 + b[6]<<1 + b[7]) |