Adding Google benchmarking library.

third_party/google_benchmark/src/reporter.cc

+// Copyright 2015 Google Inc. All rights reserved.
+//
+// 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.
+
+#include "benchmark/reporter.h"
+#include "timers.h"
+
+#include <cstdlib>
+
+#include <iostream>
+#include <tuple>
+#include <vector>
+
+#include "check.h"
+#include "stat.h"
+
+namespace benchmark {
+
+BenchmarkReporter::BenchmarkReporter()
+    : output_stream_(&std::cout), error_stream_(&std::cerr) {}
+
+BenchmarkReporter::~BenchmarkReporter() {}
+
+void BenchmarkReporter::PrintBasicContext(std::ostream *out_ptr,
+                                          Context const &context) {
+  CHECK(out_ptr) << "cannot be null";
+  auto &Out = *out_ptr;
+
+  Out << "Run on (" << context.num_cpus << " X " << context.mhz_per_cpu
+      << " MHz CPU " << ((context.num_cpus > 1) ? "s" : "") << ")\n";
+
+  Out << LocalDateTimeString() << "\n";
+
+  if (context.cpu_scaling_enabled) {
+    Out << "***WARNING*** CPU scaling is enabled, the benchmark "
+           "real time measurements may be noisy and will incur extra "
+           "overhead.\n";
+  }
+
+#ifndef NDEBUG
+  Out << "***WARNING*** Library was built as DEBUG. Timings may be "
+         "affected.\n";
+#endif
+}
+
+double BenchmarkReporter::Run::GetAdjustedRealTime() const {
+  double new_time = real_accumulated_time * GetTimeUnitMultiplier(time_unit);
+  if (iterations != 0) new_time /= static_cast<double>(iterations);
+  return new_time;
+}
+
+double BenchmarkReporter::Run::GetAdjustedCPUTime() const {
+  double new_time = cpu_accumulated_time * GetTimeUnitMultiplier(time_unit);
+  if (iterations != 0) new_time /= static_cast<double>(iterations);
+  return new_time;
+}
+
+}  // end namespace benchmark