fix zero being power of two (#1684)

prysmaticlabs · Feb 22, 2019 · 9f533fb · 9f533fb
1 parent 69058c1
commit 9f533fb
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diff --git a/shared/mathutil/math_helper.go b/shared/mathutil/math_helper.go
@@ -27,7 +27,7 @@ func CeilDiv8(n int) int {
 // IsPowerOf2 returns true if n is an
 // exact power of two. False otherwise.
 func IsPowerOf2(n uint64) bool {
-	return (n & (n - 1)) == 0
+	return n != 0 && (n&(n-1)) == 0
 }
 
 // PowerOf2 returns an integer that is the provided

diff --git a/shared/mathutil/math_helper_test.go b/shared/mathutil/math_helper_test.go
@@ -95,6 +95,10 @@ func TestIsPowerOf2(t *testing.T) {
 			a: 1024,
 			b: true,
 		},
+		{
+			a: 0,
+			b: false,
+		},
 	}
 	for _, tt := range tests {
 		if tt.b != IsPowerOf2(tt.a) {