Initial commit

libraries/crypto/src/util.rs

@@ -0,0 +1,41 @@
+// Copyright 2019 Google LLC
+//
+// 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.
+
+#[cfg(test)]
+use subtle::CtOption;
+
+pub type Block16 = [u8; 16];
+
+#[inline(always)]
+pub fn xor_block_16(block: &mut Block16, mask: &Block16) {
+    for i in 0..16 {
+        block[i] ^= mask[i];
+    }
+}
+
+#[cfg(test)]
+pub trait ToOption<T> {
+    fn to_option(self) -> Option<T>;
+}
+
+#[cfg(test)]
+impl<T> ToOption<T> for CtOption<T> {
+    fn to_option(self) -> Option<T> {
+        if bool::from(self.is_some()) {
+            Some(self.unwrap())
+        } else {
+            None
+        }
+    }
+}