Merge pull request #20 from libp2p/nit/performance

small perf improvements

keyspace/xor.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"math/big"
+	"math/bits"
 
 	u "github.com/ipfs/go-ipfs-util"
 )
@@ -44,23 +45,14 @@ func (s *xorKeySpace) Distance(k1, k2 Key) *big.Int {
 
 // Less returns whether the first key is smaller than the second.
 func (s *xorKeySpace) Less(k1, k2 Key) bool {
-	a := k1.Bytes
-	b := k2.Bytes
-	for i := 0; i < len(a); i++ {
-		if a[i] != b[i] {
-			return a[i] < b[i]
-		}
-	}
-	return true
+	return bytes.Compare(k1.Bytes, k2.Bytes) < 0
 }
 
 // ZeroPrefixLen returns the number of consecutive zeroes in a byte slice.
 func ZeroPrefixLen(id []byte) int {
-	for i := 0; i < len(id); i++ {
-		for j := 0; j < 8; j++ {
-			if (id[i]>>uint8(7-j))&0x1 != 0 {
-				return i*8 + j
-			}
+	for i, b := range id {
+		if b != 0 {
+			return i*8 + bits.LeadingZeros8(uint8(b))
 		}
 	}
 	return len(id) * 8

table.go

@@ -89,12 +89,10 @@ func (rt *RoutingTable) Update(p peer.ID) {
 		// If this bucket is the rightmost bucket, and its full
 		// we need to split it and create a new bucket
 		if bucketID == len(rt.Buckets)-1 {
-			rt.PeerRemoved(rt.nextBucket())
-			return
+			rt.nextBucket()
 		} else {
 			// If the bucket cant split kick out least active node
 			rt.PeerRemoved(bucket.PopBack())
-			return
 		}
 	}
 }
@@ -117,19 +115,18 @@ func (rt *RoutingTable) Remove(p peer.ID) {
 	rt.PeerRemoved(p)
 }
 
-func (rt *RoutingTable) nextBucket() peer.ID {
+func (rt *RoutingTable) nextBucket() {
 	bucket := rt.Buckets[len(rt.Buckets)-1]
 	newBucket := bucket.Split(len(rt.Buckets)-1, rt.local)
 	rt.Buckets = append(rt.Buckets, newBucket)
 	if newBucket.Len() > rt.bucketsize {
-		return rt.nextBucket()
+		rt.nextBucket()
 	}
 
 	// If all elements were on left side of split...
 	if bucket.Len() > rt.bucketsize {
-		return bucket.PopBack()
+		rt.PeerRemoved(bucket.PopBack())
 	}
-	return ""
 }
 
 // Find a specific peer by ID or return nil