1 files changed, 52 insertions, 0 deletions
diff --git a/pkg/bits/bits_template.go b/pkg/bits/bits_template.go
new file mode 100644
index 000000000..998645388
--- /dev/null
+++ b/pkg/bits/bits_template.go
@@ -0,0 +1,52 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package bits
+
+// Non-atomic bit operations on a template type T.
+
+// T is a required type parameter that must be an integral type.
+type T uint64
+
+// IsOn returns true if *all* bits set in 'bits' are set in 'mask'.
+func IsOn(mask, bits T) bool {
+	return mask&bits == bits
+}
+
+// IsAnyOn returns true if *any* bit set in 'bits' is set in 'mask'.
+func IsAnyOn(mask, bits T) bool {
+	return mask&bits != 0
+}
+
+// Mask returns a T with all of the given bits set.
+func Mask(is ...int) T {
+	ret := T(0)
+	for _, i := range is {
+		ret |= MaskOf(i)
+	}
+	return ret
+}
+
+// MaskOf is like Mask, but sets only a single bit (more efficiently).
+func MaskOf(i int) T {
+	return T(1) << T(i)
+}
+
+// IsPowerOfTwo returns true if v is power of 2.
+func IsPowerOfTwo(v T) bool {
+	if v == 0 {
+		return false
+	}
+	return v&(v-1) == 0
+}