moved XOR keyspace -> util

xor.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"math/big"
+
+	u "github.com/jbenet/go-ipfs/util"
 )
 
 // XORKeySpace is a KeySpace which:
@@ -33,7 +35,7 @@ func (s *xorKeySpace) Equal(k1, k2 Key) bool {
 // Distance returns the distance metric in this key space
 func (s *xorKeySpace) Distance(k1, k2 Key) *big.Int {
 	// XOR the keys
-	k3 := XOR(k1.Bytes, k2.Bytes)
+	k3 := u.XOR(k1.Bytes, k2.Bytes)
 
 	// interpret it as an integer
 	dist := big.NewInt(0).SetBytes(k3)
@@ -52,15 +54,6 @@ func (s *xorKeySpace) Less(k1, k2 Key) bool {
 	return true
 }
 
-// XOR takes two byte slices, XORs them together, returns the resulting slice.
-func XOR(a, b []byte) []byte {
-	c := make([]byte, len(a))
-	for i := 0; i < len(a); i++ {
-		c[i] = a[i] ^ b[i]
-	}
-	return c
-}
-
 // ZeroPrefixLen returns the number of consecutive zeroes in a byte slice.
 func ZeroPrefixLen(id []byte) int {
 	for i := 0; i < len(id); i++ {

xor_test.go

@@ -4,34 +4,9 @@ import (
 	"bytes"
 	"math/big"
 	"testing"
-)
-
-func TestXOR(t *testing.T) {
-	cases := [][3][]byte{
-		[3][]byte{
-			[]byte{0xFF, 0xFF, 0xFF},
-			[]byte{0xFF, 0xFF, 0xFF},
-			[]byte{0x00, 0x00, 0x00},
-		},
-		[3][]byte{
-			[]byte{0x00, 0xFF, 0x00},
-			[]byte{0xFF, 0xFF, 0xFF},
-			[]byte{0xFF, 0x00, 0xFF},
-		},
-		[3][]byte{
-			[]byte{0x55, 0x55, 0x55},
-			[]byte{0x55, 0xFF, 0xAA},
-			[]byte{0x00, 0xAA, 0xFF},
-		},
-	}
 
-	for _, c := range cases {
-		r := XOR(c[0], c[1])
-		if !bytes.Equal(r, c[2]) {
-			t.Error("XOR failed")
-		}
-	}
-}
+	u "github.com/jbenet/go-ipfs/util"
+)
 
 func TestPrefixLen(t *testing.T) {
 	cases := [][]byte{
@@ -126,7 +101,7 @@ func TestDistancesAndCenterSorting(t *testing.T) {
 	}
 
 	d1 := keys[2].Distance(keys[5])
-	d2 := XOR(keys[2].Bytes, keys[5].Bytes)
+	d2 := u.XOR(keys[2].Bytes, keys[5].Bytes)
 	d2 = d2[len(keys[2].Bytes)-len(d1.Bytes()):] // skip empty space for big
 	if !bytes.Equal(d1.Bytes(), d2) {
 		t.Errorf("bytes should be the same. %v == %v", d1.Bytes(), d2)