Adding Google benchmarking library.

third_party/google_benchmark/include/benchmark/reporter.h

Index: third_party/google_benchmark/include/benchmark/reporter.h
diff --git a/third_party/google_benchmark/include/benchmark/reporter.h b/third_party/google_benchmark/include/benchmark/reporter.h
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+// 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.
+#ifndef BENCHMARK_REPORTER_H_
+#define BENCHMARK_REPORTER_H_
+
+#include <cassert>
+#include <iosfwd>
+#include <string>
+#include <utility>
+#include <vector>
+#include <set>
+
+#include "benchmark_api.h"  // For forward declaration of BenchmarkReporter
+
+namespace benchmark {
+
+// Interface for custom benchmark result printers.
+// By default, benchmark reports are printed to stdout. However an application
+// can control the destination of the reports by calling
+// RunSpecifiedBenchmarks and passing it a custom reporter object.
+// The reporter object must implement the following interface.
+class BenchmarkReporter {
+ public:
+  struct Context {
+    int num_cpus;
+    double mhz_per_cpu;
+    bool cpu_scaling_enabled;
+
+    // The number of chars in the longest benchmark name.
+    size_t name_field_width;
+  };
+
+  struct Run {
+    Run()
+        : error_occurred(false),
+          iterations(1),
+          time_unit(kNanosecond),
+          real_accumulated_time(0),
+          cpu_accumulated_time(0),
+          bytes_per_second(0),
+          items_per_second(0),
+          max_heapbytes_used(0),
+          complexity(oNone),
+          complexity_lambda(),
+          complexity_n(0),
+          report_big_o(false),
+          report_rms(false),
+          counters() {}
+
+    std::string benchmark_name;
+    std::string report_label;  // Empty if not set by benchmark.
+    bool error_occurred;
+    std::string error_message;
+
+    int64_t iterations;
+    TimeUnit time_unit;
+    double real_accumulated_time;
+    double cpu_accumulated_time;
+
+    // Return a value representing the real time per iteration in the unit
+    // specified by 'time_unit'.
+    // NOTE: If 'iterations' is zero the returned value represents the
+    // accumulated time.
+    double GetAdjustedRealTime() const;
+
+    // Return a value representing the cpu time per iteration in the unit
+    // specified by 'time_unit'.
+    // NOTE: If 'iterations' is zero the returned value represents the
+    // accumulated time.
+    double GetAdjustedCPUTime() const;
+
+    // Zero if not set by benchmark.
+    double bytes_per_second;
+    double items_per_second;
+
+    // This is set to 0.0 if memory tracing is not enabled.
+    double max_heapbytes_used;
+
+    // Keep track of arguments to compute asymptotic complexity
+    BigO complexity;
+    BigOFunc* complexity_lambda;
+    int complexity_n;
+
+    // Inform print function whether the current run is a complexity report
+    bool report_big_o;
+    bool report_rms;
+
+    UserCounters counters;
+  };
+
+  // Construct a BenchmarkReporter with the output stream set to 'std::cout'
+  // and the error stream set to 'std::cerr'
+  BenchmarkReporter();
+
+  // Called once for every suite of benchmarks run.
+  // The parameter "context" contains information that the
+  // reporter may wish to use when generating its report, for example the
+  // platform under which the benchmarks are running. The benchmark run is
+  // never started if this function returns false, allowing the reporter
+  // to skip runs based on the context information.
+  virtual bool ReportContext(const Context& context) = 0;
+
+  // Called once for each group of benchmark runs, gives information about
+  // cpu-time and heap memory usage during the benchmark run. If the group
+  // of runs contained more than two entries then 'report' contains additional
+  // elements representing the mean and standard deviation of those runs.
+  // Additionally if this group of runs was the last in a family of benchmarks
+  // 'reports' contains additional entries representing the asymptotic
+  // complexity and RMS of that benchmark family.
+  virtual void ReportRuns(const std::vector<Run>& report) = 0;
+
+  // Called once and only once after ever group of benchmarks is run and
+  // reported.
+  virtual void Finalize() {}
+
+  // REQUIRES: The object referenced by 'out' is valid for the lifetime
+  // of the reporter.
+  void SetOutputStream(std::ostream* out) {
+    assert(out);
+    output_stream_ = out;
+  }
+
+  // REQUIRES: The object referenced by 'err' is valid for the lifetime
+  // of the reporter.
+  void SetErrorStream(std::ostream* err) {
+    assert(err);
+    error_stream_ = err;
+  }
+
+  std::ostream& GetOutputStream() const { return *output_stream_; }
+
+  std::ostream& GetErrorStream() const { return *error_stream_; }
+
+  virtual ~BenchmarkReporter();
+
+  // Write a human readable string to 'out' representing the specified
+  // 'context'.
+  // REQUIRES: 'out' is non-null.
+  static void PrintBasicContext(std::ostream* out, Context const& context);
+
+ private:
+  std::ostream* output_stream_;
+  std::ostream* error_stream_;
+};
+
+// Simple reporter that outputs benchmark data to the console. This is the
+// default reporter used by RunSpecifiedBenchmarks().
+class ConsoleReporter : public BenchmarkReporter {
+public:
+  enum OutputOptions {
+    OO_None = 0,
+    OO_Color = 1,
+    OO_Tabular = 2,
+    OO_ColorTabular = OO_Color|OO_Tabular,
+    OO_Defaults = OO_ColorTabular
+  };
+  explicit ConsoleReporter(OutputOptions opts_ = OO_Defaults)
+      : output_options_(opts_), name_field_width_(0),
+        prev_counters_(), printed_header_(false) {}
+
+  virtual bool ReportContext(const Context& context);
+  virtual void ReportRuns(const std::vector<Run>& reports);
+
+ protected:
+  virtual void PrintRunData(const Run& report);
+  virtual void PrintHeader(const Run& report);
+
+  OutputOptions output_options_;
+  size_t name_field_width_;
+  UserCounters prev_counters_;
+  bool printed_header_;
+};
+
+class JSONReporter : public BenchmarkReporter {
+ public:
+  JSONReporter() : first_report_(true) {}
+  virtual bool ReportContext(const Context& context);
+  virtual void ReportRuns(const std::vector<Run>& reports);
+  virtual void Finalize();
+
+ private:
+  void PrintRunData(const Run& report);
+
+  bool first_report_;
+};
+
+class CSVReporter : public BenchmarkReporter {
+ public:
+  CSVReporter() : printed_header_(false) {}
+  virtual bool ReportContext(const Context& context);
+  virtual void ReportRuns(const std::vector<Run>& reports);
+
+ private:
+  void PrintRunData(const Run& report);
+
+  bool printed_header_;
+  std::set< std::string > user_counter_names_;
+};
+
+inline const char* GetTimeUnitString(TimeUnit unit) {
+  switch (unit) {
+    case kMillisecond:
+      return "ms";
+    case kMicrosecond:
+      return "us";
+    case kNanosecond:
+    default:
+      return "ns";
+  }
+}
+
+inline double GetTimeUnitMultiplier(TimeUnit unit) {
+  switch (unit) {
+    case kMillisecond:
+      return 1e3;
+    case kMicrosecond:
+      return 1e6;
+    case kNanosecond:
+    default:
+      return 1e9;
+  }
+}
+
+}  // end namespace benchmark
+#endif  // BENCHMARK_REPORTER_H_