Replace multi if block with a keyset and range

secret_handshake.go

@@ -13,29 +13,25 @@ const (
 // Handshake receives an integer argument and returns a string slice with
 // the code words in the proper sequence.
 func Handshake(i int) (h []string) {
-	// Store the handshake phrases in a string slice (maps are slow).
-	s := []string{"wink", "double blink", "close your eyes", "jump"}
-
 	// Return the original nil slice if the integer is negative.
 	if i < 0 {
 		return h
 	}
 
-	// Build the slice by bitmasking the integer.
-	if i&wnk != 0 {
-		h = append(h, s[0])
-	}
-	if i&bli != 0 {
-		h = append(h, s[1])
-	}
-	if i&clo != 0 {
-		h = append(h, s[2])
-	}
-	if i&jmp != 0 {
-		h = append(h, s[3])
+	// Store the handshake phrases in a string slice (maps are slow).
+	s := []string{"wink", "double blink", "close your eyes", "jump"}
+
+	// Define an ordered set of keys.
+	keys := []int{wnk, bli, clo, jmp}
+
+	// Build the string slice by bitmasking the integer.
+	for n, k := range keys {
+		if i&k != 0 {
+			h = append(h, s[n])
+		}
 	}
 
-	// Reverse the slice if the 5th bit is set.
+	// Reverse the slice (in-place) if the 5th bit is set.
 	if i&rev != 0 {
 		for i, j := 0, len(h)-1; i < j; i, j = i+1, j-1 {
 			h[i], h[j] = h[j], h[i]
@@ -45,7 +41,7 @@ func Handshake(i int) (h []string) {
 	return h
 }
 
-// Revision 1 benchmark:
+// Revision 2 benchmark:
 //
 // PASS
-// BenchmarkHandshake-12	 5000000	       334 ns/op
+// BenchmarkHandshake-12	 5000000	       338 ns/op