A couple of tighter loops.

(I was looking at this code accidentally because of some gofmt
issues and thought that one could write this more effectively.
You may have deliberately chosen not to use ranges here to make
the index range clearer. Just let me know.)

R=agl, agl1
CC=golang-dev
https://golang.org/cl/181084

src/pkg/crypto/md5/md5.go

@@ -68,8 +68,8 @@ func (d *digest) Write(p []byte) (nn int, err os.Error) {
 	n := _Block(d, p)
 	p = p[n:]
 	if len(p) > 0 {
-		for i := 0; i < len(p); i++ {
-			d.x[i] = p[i]
+		for i, x := range p {
+			d.x[i] = x
 		}
 		d.nx = len(p)
 	}
@@ -100,16 +100,12 @@ func (d *digest) Sum() []byte {
 
 	p := make([]byte, 16)
 	j := 0
-	for i := 0; i < 4; i++ {
-		s := d.s[i]
-		p[j] = byte(s)
-		j++
-		p[j] = byte(s >> 8)
-		j++
-		p[j] = byte(s >> 16)
-		j++
-		p[j] = byte(s >> 24)
-		j++
+	for _, s := range d.s {
+		p[j+0] = byte(s >> 0)
+		p[j+1] = byte(s >> 8)
+		p[j+2] = byte(s >> 16)
+		p[j+3] = byte(s >> 24)
+		j += 4
 	}
 	return p
 }