Merge branch 'master' of https://github.com/google/uuid

marshal.go

@@ -4,10 +4,7 @@
 
 package uuid
 
-import (
-	"fmt"
-	"unsafe"
-)
+import "fmt"
 
 // MarshalText implements encoding.TextMarshaler.
 func (uuid UUID) MarshalText() ([]byte, error) {
@@ -20,7 +17,7 @@ func (uuid UUID) MarshalText() ([]byte, error) {
 func (uuid *UUID) UnmarshalText(data []byte) error {
 	// See comment in ParseBytes why we do this.
 	// id, err := ParseBytes(data)
-	id, err := Parse(*(*string)(unsafe.Pointer(&data)))
+	id, err := ParseBytes(data)
 	if err == nil {
 		*uuid = id
 	}

util.go

@@ -35,9 +35,9 @@ var xvalues = [256]byte{
 	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
 }
 
-// xtob converts the the first two hex bytes of x into a byte.
-func xtob(x string) (byte, bool) {
-	b1 := xvalues[x[0]]
-	b2 := xvalues[x[1]]
+// xtob converts hex characters x1 and x2 into a byte.
+func xtob(x1, x2 byte) (byte, bool) {
+	b1 := xvalues[x1]
+	b2 := xvalues[x2]
 	return (b1 << 4) | b2, b1 != 255 && b2 != 255
 }

uuid.go

@@ -5,13 +5,13 @@
 package uuid
 
 import (
+	"bytes"
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
 	"strings"
-	"unsafe"
 )
 
 // A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC
@@ -58,7 +58,7 @@ func Parse(s string) (UUID, error) {
 		14, 16,
 		19, 21,
 		24, 26, 28, 30, 32, 34} {
-		if v, ok := xtob(s[x:]); !ok {
+		if v, ok := xtob(s[x], s[x+1]); !ok {
 			return uuid, errors.New("invalid UUID format")
 		} else {
 			uuid[i] = v
@@ -69,12 +69,32 @@ func Parse(s string) (UUID, error) {
 
 // ParseBytes is like Parse, except it parses a byte slice instead of a string.
 func ParseBytes(b []byte) (UUID, error) {
-	// Parsing a string is actually faster than parsing a byte slice as it
-	// is cheaper to slice a string.  Further, it is not safe to convert
-	// a string into a byte slice but the opposite direction is.  These
-	// stem from the fact that a byte slice is 3 words while a string
-	// is only 2 words.
-	return Parse(*(*string)(unsafe.Pointer(&b)))
+	var uuid UUID
+	if len(b) != 36 {
+		if len(b) != 36+9 {
+			return uuid, fmt.Errorf("invalid UUID length: %d", len(b))
+		}
+		if !bytes.Equal(bytes.ToLower(b[:9]), []byte("urn:uuid:")) {
+			return uuid, fmt.Errorf("invalid urn prefix: %q", b[:9])
+		}
+		b = b[9:]
+	}
+	if b[8] != '-' || b[13] != '-' || b[18] != '-' || b[23] != '-' {
+		return uuid, errors.New("invalid UUID format")
+	}
+	for i, x := range [16]int{
+		0, 2, 4, 6,
+		9, 11,
+		14, 16,
+		19, 21,
+		24, 26, 28, 30, 32, 34} {
+		if v, ok := xtob(b[x], b[x+1]); !ok {
+			return uuid, errors.New("invalid UUID format")
+		} else {
+			uuid[i] = v
+		}
+	}
+	return uuid, nil
 }
 
 // Must returns uuid if err is nil and panics otherwise.

uuid_test.go

@@ -6,12 +6,12 @@ package uuid
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
 	"testing"
 	"time"
+	"unsafe"
 )
 
 type test struct {
@@ -466,59 +466,26 @@ func BenchmarkParseBytes(b *testing.B) {
 	}
 }
 
-// parseBytesCopy is to benchmark not using unsafe.
-func parseBytesCopy(b []byte) (UUID, error) {
-	return Parse(string(b))
+// parseBytesUnsafe is to benchmark using unsafe.
+func parseBytesUnsafe(b []byte) (UUID, error) {
+	return Parse(*(*string)(unsafe.Pointer(&b)))
 }
 
-// xtobb converts the the first two hex bytes of x into a byte.
-func xtobb(x []byte) (byte, bool) {
-	b1 := xvalues[x[0]]
-	b2 := xvalues[x[1]]
-	return (b1 << 4) | b2, b1 != 255 && b2 != 255
-}
 
-// parseBytes is the same as Parse, but with byte slices.  It demonstrates
-// that it is faster to convert the byte slice into a string and then parse
-// than to parse the byte slice directly.
-func parseBytes(s []byte) (UUID, error) {
-	var uuid UUID
-	if len(s) != 36 {
-		if len(s) != 36+9 {
-			return uuid, fmt.Errorf("invalid UUID length: %d", len(s))
-		}
-		if !bytes.Equal(bytes.ToLower(s[:9]), []byte("urn:uuid:")) {
-			return uuid, fmt.Errorf("invalid urn prefix: %q", s[:9])
-		}
-		s = s[9:]
-	}
-	if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
-		return uuid, errors.New("invalid UUID format")
-	}
-	for i, x := range [16]int{
-		0, 2, 4, 6,
-		9, 11,
-		14, 16,
-		19, 21,
-		24, 26, 28, 30, 32, 34} {
-		if v, ok := xtobb(s[x:]); !ok {
-			return uuid, errors.New("invalid UUID format")
-		} else {
-			uuid[i] = v
-		}
-	}
-	return uuid, nil
-}
-
-func BenchmarkParseBytesNative(b *testing.B) {
+func BenchmarkParseBytesUnsafe(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		_, err := parseBytes(asBytes)
+		_, err := parseBytesUnsafe(asBytes)
 		if err != nil {
 			b.Fatal(err)
 		}
 	}
 }
 
+// parseBytesCopy is to benchmark not using unsafe.
+func parseBytesCopy(b []byte) (UUID, error) {
+	return Parse(string(b))
+}
+
 func BenchmarkParseBytesCopy(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		_, err := parseBytesCopy(asBytes)