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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
package main
import (
"crypto/sha1"
"encoding/hex"
"fmt"
"io"
"math/rand"
"time"
)
const ihLength = 20
func genInfoHash() string {
random := rand.New(rand.NewSource(time.Now().UnixNano()))
hash := sha1.New()
io.WriteString(hash, time.Now().String())
io.WriteString(hash, string(random.Int()))
ih := hash.Sum(nil)
return string(ih)
}
func genNeighbour(first, second string) string {
s := second[:10] + first[10:]
return s
}
func decodeInfoHash(in string) (b string, err error) {
var h []byte
h, err = hex.DecodeString(in)
if len(h) != ihLength {
return "", fmt.Errorf("Decoded infoHash is incorrect length, got %d", len(h))
}
return string(h), err
}
/*
func isValidInfoHash(id string) bool {
ih, err := hex.DecodeString(id)
if err != nil {
return false
}
return len(ih) == ihLength
}
func (ih infoHash) xor(other infoHash) (ret []byte) {
if len(ih) != len(other) {
return []byte("")
}
ret = make([]byte, ihLength)
for i := 0; i < ihLength; i++ {
ret[i] = ih[i] ^ other[i]
}
return
}
// Effectively the "distance"
// XORed then number of common bits
func (ih infoHash) prefixLen(other infoHash) (ret int) {
//fmt.Printf("ih = %s, other = %s\n", ih.asHex(), other.asHex())
id1, id2 := []byte(ih), []byte(other)
xor := make([]byte, ihLength)
i := 0
for ; i < ihLength; i++ {
xor[i] = id1[i] ^ id2[i]
}
for i := 0; i < ihLength; i++ {
for j := 0; j < 8; j++ {
if (xor[i]>>uint8(7-j))&0x1 != 0 {
return i*8 + j
}
}
}
return ihLength*8 - 1
}
// Comparitor for iterable
func (ih infoHash) Less(other interface{}) bool {
for i := 0; i < ihLength; i++ {
if ih[i] != other.(infoHash)[i] {
return ih[i] < other.(infoHash)[i]
}
}
return false
}
*/
|
