upload android base code part6

android/system/netd/include/Stopwatch.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef NETD_INCLUDE_STOPWATCH_H
+#define NETD_INCLUDE_STOPWATCH_H
+
+#include <chrono>
+
+class Stopwatch {
+public:
+    Stopwatch() : mStart(clock::now()) {}
+
+    virtual ~Stopwatch() {};
+
+    float timeTaken() const {
+        return getElapsed(clock::now());
+    }
+
+    float getTimeAndReset() {
+        const auto& now = clock::now();
+        float elapsed = getElapsed(now);
+        mStart = now;
+        return elapsed;
+    }
+
+private:
+    typedef std::chrono::steady_clock clock;
+    typedef std::chrono::time_point<clock> time_point;
+    time_point mStart;
+
+    float getElapsed(const time_point& now) const {
+        using ms = std::chrono::duration<float, std::ratio<1, 1000>>;
+        return (std::chrono::duration_cast<ms>(now - mStart)).count();
+    }
+};
+
+#endif  // NETD_INCLUDE_STOPWATCH_H