equalize sizes
Juan Batiz-Benet committed
Jul 29, 2014 at 17:53 UTC
550971fba6d734d8035e7b1ba5d0171df0ebe0d8
1 file changed
+50
-36
routing/dht/table.go
+50
-36
@@ -1,61 +1,75 @@
1
package dht
2
3
import (
4
- "container/list"
4
+ "bytes"
5
+ "container/list"
6
)
7
7
-
8
// ID for IpfsDHT should be a byte slice, to allow for simpler operations
9
// (xor). DHT ids are based on the peer.IDs.
10
//
11
-// NOTE: peer.IDs are biased because they are (a) multihashes (first bytes
12
-// biased), and (b) first bits are zeroes when using the S/Kademlia PoW.
13
-// Thus, may need to re-hash keys (uniform dist). TODO(jbenet)
11
+// NOTE: peer.IDs are biased because they are multihashes (first bytes
12
+// biased). Thus, may need to re-hash keys (uniform dist). TODO(jbenet)
13
type ID []byte
14
15
// Bucket holds a list of peers.
16
type Bucket []*list.List
17
19
-
18
// RoutingTable defines the routing table.
19
type RoutingTable struct {
20
23
- // kBuckets define all the fingers to other nodes.
24
- Buckets []Bucket
21
+ // kBuckets define all the fingers to other nodes.
22
+ Buckets []Bucket
23
}
24
25
+func (id ID) Equal(other ID) bool {
26
+ return bytes.Equal(id, other)
27
+}
28
+
29
+func (id ID) Less(other interface{}) bool {
30
+ a, b := equalizeSizes(id, other.(ID))
31
+ for i := 0; i < len(a); i++ {
32
+ if a[i] != b[i] {
33
+ return a[i] < b[i]
34
+ }
35
+ }
36
+ return len(a) < len(b)
37
+}
38
39
func (id ID) commonPrefixLen() int {
29
- for i := 0; i < len(id); i++ {
30
- for j := 0; j < 8; j++ {
31
- if (id[i] >> uint8(7 - j)) & 0x1 != 0 {
32
- return i * 8 + j;
33
- }
34
- }
35
- }
36
- return len(id) * 8 - 1;
40
+ for i := 0; i < len(id); i++ {
41
+ for j := 0; j < 8; j++ {
42
+ if (id[i]>>uint8(7-j))&0x1 != 0 {
43
+ return i*8 + j
44
+ }
45
+ }
46
+ }
47
+ return len(id)*8 - 1
48
}
49
50
func xor(a, b ID) ID {
51
+ a, b = equalizeSizes(a, b)
52
+
53
+ c := make(ID, len(a))
54
+ for i := 0; i < len(a); i++ {
55
+ c[i] = a[i] ^ b[i]
56
+ }
57
+ return c
58
+}
59
+
60
+func equalizeSizes(a, b ID) (ID, ID) {
61
+ la := len(a)
62
+ lb := len(b)
63
+
64
+ if la < lb {
65
+ na := make([]byte, lb)
66
+ copy(na, a)
67
+ a = na
68
+ } else if lb < la {
69
+ nb := make([]byte, la)
70
+ copy(nb, b)
71
+ b = nb
72
+ }
73
41
- // ids may actually be of different sizes.
42
- var ba ID
43
- var bb ID
44
- if len(a) >= len(b) {
45
- ba = a
46
- bb = b
47
- } else {
48
- ba = b
49
- bb = a
50
- }
51
-
52
- c := make(ID, len(ba))
53
- for i := 0; i < len(ba); i++ {
54
- if len(bb) > i {
55
- c[i] = ba[i] ^ bb[i]
56
- } else {
57
- c[i] = ba[i] ^ 0
58
- }
59
- }
60
- return c
74
+ return a, b
75
}