Decode is now 65% faster

Author: matthinrichsen-wf

numerics/hilbert/hilbert.go

@@ -51,9 +51,7 @@ func rotate(n, rx, ry int32, x, y int32) (int32, int32) {
 			y = n - 1 - y
 		}
 
-		t := x
-		x = y
-		y = t
+		x, y = y, x
 	}
 	return x, y
 }
@@ -63,7 +61,7 @@ func rotate(n, rx, ry int32, x, y int32) (int32, int32) {
 func Encode(x, y int32) int64 {
 	var rx, ry int32
 	var d int64
-	for s := int32(n >> 1); s > 0; s = s >> 1 {
+	for s := int32(n >> 1); s > 0; s >>= 1 {
 		rx = boolToInt(x&s > 0)
 		ry = boolToInt(y&s > 0)
 		d += int64(int64(s) * int64(s) * int64(((3 * rx) ^ ry)))
@@ -80,13 +78,13 @@ func Decode(h int64) (int32, int32) {
 	var x, y int32
 	t := h
 
-	for s := int64(1); s < int64(n); s *= 2 {
+	for s := int64(1); s < int64(n); s <<= 1 {
 		rx = 1 & (t / 2)
 		ry = 1 & (t ^ rx)
 		x, y = rotate(int32(s), int32(rx), int32(ry), x, y)
 		x += int32(s * rx)
 		y += int32(s * ry)
-		t /= 4
+		t >>= 2
 	}
 
 	return x, y