Add a basic implementation of class CycleTimer

It is used by baseapi_test.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

unittest/cycletimer.h

@@ -0,0 +1,60 @@
+// (C) Copyright 2017, Google Inc.
+// 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.
+// Portability include to match the Google test environment.
+
+#ifndef TESSERACT_UNITTEST_CYCLETIMER_H
+#define TESSERACT_UNITTEST_CYCLETIMER_H
+
+#include "absl/time/clock.h" // for GetCurrentTimeNanos
+
+// See https://github.com/google/or-tools/blob/master/ortools/base/timer.h
+class CycleTimer {
+public:
+  CycleTimer() {
+    Reset();
+  }
+
+  void Reset() {
+    running_ = false;
+    sum_ = 0;
+  }
+
+  // When Start() is called multiple times, only the most recent is used.
+  void Start() {
+    running_ = true;
+    start_ = absl::GetCurrentTimeNanos();
+  }
+
+  void Restart() {
+    sum_ = 0;
+    Start();
+  }
+
+  void Stop() {
+    if (running_) {
+      sum_ += absl::GetCurrentTimeNanos() - start_;
+      running_ = false;
+    }
+  }
+  int64_t GetInMs() const { return GetNanos() / 1000000; }
+
+ protected:
+  int64_t GetNanos() const {
+    return running_ ? absl::GetCurrentTimeNanos() - start_ + sum_ : sum_;
+  }
+
+ private:
+  bool running_;
+  int64_t start_;
+  int64_t sum_;
+};
+
+#endif  // TESSERACT_UNITTEST_CYCLETIMER_H