liblog: Add liblog test suite

Change-Id: Ia6d6821e8546e0eccacab812d39d529ea0372c6a
diff --git a/liblog/tests/benchmark_main.cpp b/liblog/tests/benchmark_main.cpp
new file mode 100644
index 0000000..942e12c
--- /dev/null
+++ b/liblog/tests/benchmark_main.cpp
@@ -0,0 +1,245 @@
+/*
+ * Copyright (C) 2012-2013 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.
+ */
+
+#include <benchmark.h>
+
+#include <regex.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <string>
+#include <map>
+#include <vector>
+
+static uint64_t gBytesProcessed;
+static uint64_t gBenchmarkTotalTimeNs;
+static uint64_t gBenchmarkTotalTimeNsSquared;
+static uint64_t gBenchmarkNum;
+static uint64_t gBenchmarkStartTimeNs;
+
+typedef std::vector< ::testing::Benchmark* > BenchmarkList;
+static BenchmarkList* gBenchmarks;
+
+static int Round(int n) {
+  int base = 1;
+  while (base*10 < n) {
+    base *= 10;
+  }
+  if (n < 2*base) {
+    return 2*base;
+  }
+  if (n < 5*base) {
+    return 5*base;
+  }
+  return 10*base;
+}
+
+static uint64_t NanoTime() {
+  struct timespec t;
+  t.tv_sec = t.tv_nsec = 0;
+  clock_gettime(CLOCK_MONOTONIC, &t);
+  return static_cast<uint64_t>(t.tv_sec) * 1000000000ULL + t.tv_nsec;
+}
+
+namespace testing {
+
+int PrettyPrintInt(char* str, int len, unsigned int arg)
+{
+  if (arg >= (1<<30) && arg % (1<<30) == 0) {
+    return snprintf(str, len, "%uGi", arg/(1<<30));
+  } else if (arg >= (1<<20) && arg % (1<<20) == 0) {
+    return snprintf(str, len, "%uMi", arg/(1<<20));
+  } else if (arg >= (1<<10) && arg % (1<<10) == 0) {
+    return snprintf(str, len, "%uKi", arg/(1<<10));
+  } else if (arg >= 1000000000 && arg % 1000000000 == 0) {
+    return snprintf(str, len, "%uG", arg/1000000000);
+  } else if (arg >= 1000000 && arg % 1000000 == 0) {
+    return snprintf(str, len, "%uM", arg/1000000);
+  } else if (arg >= 1000 && arg % 1000 == 0) {
+    return snprintf(str, len, "%uK", arg/1000);
+  } else {
+    return snprintf(str, len, "%u", arg);
+  }
+}
+
+bool ShouldRun(Benchmark* b, int argc, char* argv[]) {
+  if (argc == 1) {
+    return true;  // With no arguments, we run all benchmarks.
+  }
+  // Otherwise, we interpret each argument as a regular expression and
+  // see if any of our benchmarks match.
+  for (int i = 1; i < argc; i++) {
+    regex_t re;
+    if (regcomp(&re, argv[i], 0) != 0) {
+      fprintf(stderr, "couldn't compile \"%s\" as a regular expression!\n", argv[i]);
+      exit(EXIT_FAILURE);
+    }
+    int match = regexec(&re, b->Name(), 0, NULL, 0);
+    regfree(&re);
+    if (match != REG_NOMATCH) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void BenchmarkRegister(Benchmark* b) {
+  if (gBenchmarks == NULL) {
+    gBenchmarks = new BenchmarkList;
+  }
+  gBenchmarks->push_back(b);
+}
+
+void RunRepeatedly(Benchmark* b, int iterations) {
+  gBytesProcessed = 0;
+  ResetBenchmarkTiming();
+  uint64_t StartTimeNs = NanoTime();
+  b->RunFn(iterations);
+  // Catch us if we fail to log anything.
+  if ((gBenchmarkTotalTimeNs == 0)
+   && (StartTimeNs != 0)
+   && (gBenchmarkStartTimeNs == 0)) {
+    gBenchmarkTotalTimeNs = NanoTime() - StartTimeNs;
+  }
+}
+
+void Run(Benchmark* b) {
+  // run once in case it's expensive
+  unsigned iterations = 1;
+  uint64_t s = NanoTime();
+  RunRepeatedly(b, iterations);
+  s = NanoTime() - s;
+  while (s < 2e9 && gBenchmarkTotalTimeNs < 1e9 && iterations < 1e9) {
+    unsigned last = iterations;
+    if (gBenchmarkTotalTimeNs/iterations == 0) {
+      iterations = 1e9;
+    } else {
+      iterations = 1e9 / (gBenchmarkTotalTimeNs/iterations);
+    }
+    iterations = std::max(last + 1, std::min(iterations + iterations/2, 100*last));
+    iterations = Round(iterations);
+    s = NanoTime();
+    RunRepeatedly(b, iterations);
+    s = NanoTime() - s;
+  }
+
+  char throughput[100];
+  throughput[0] = '\0';
+  if (gBenchmarkTotalTimeNs > 0 && gBytesProcessed > 0) {
+    double mib_processed = static_cast<double>(gBytesProcessed)/1e6;
+    double seconds = static_cast<double>(gBenchmarkTotalTimeNs)/1e9;
+    snprintf(throughput, sizeof(throughput), " %8.2f MiB/s", mib_processed/seconds);
+  }
+
+  char full_name[100];
+  snprintf(full_name, sizeof(full_name), "%s%s%s", b->Name(),
+           b->ArgName() ? "/" : "",
+           b->ArgName() ? b->ArgName() : "");
+
+  uint64_t mean = gBenchmarkTotalTimeNs / iterations;
+  uint64_t sdev = 0;
+  if (gBenchmarkNum == iterations) {
+    mean = gBenchmarkTotalTimeNs / gBenchmarkNum;
+    uint64_t nXvariance = gBenchmarkTotalTimeNsSquared * gBenchmarkNum
+                        - (gBenchmarkTotalTimeNs * gBenchmarkTotalTimeNs);
+    sdev = (sqrt((double)nXvariance) / gBenchmarkNum / gBenchmarkNum) + 0.5;
+  }
+  if (mean > (10000 * sdev)) {
+    printf("%-25s %10llu %10llu%s\n", full_name,
+            static_cast<uint64_t>(iterations), mean, throughput);
+  } else {
+    printf("%-25s %10llu %10llu(\317\203%llu)%s\n", full_name,
+           static_cast<uint64_t>(iterations), mean, sdev, throughput);
+  }
+  fflush(stdout);
+}
+
+}  // namespace testing
+
+void SetBenchmarkBytesProcessed(uint64_t x) {
+  gBytesProcessed = x;
+}
+
+void ResetBenchmarkTiming() {
+  gBenchmarkStartTimeNs = 0;
+  gBenchmarkTotalTimeNs = 0;
+  gBenchmarkTotalTimeNsSquared = 0;
+  gBenchmarkNum = 0;
+}
+
+void StopBenchmarkTiming(void) {
+  if (gBenchmarkStartTimeNs != 0) {
+    int64_t diff = NanoTime() - gBenchmarkStartTimeNs;
+    gBenchmarkTotalTimeNs += diff;
+    gBenchmarkTotalTimeNsSquared += diff * diff;
+    ++gBenchmarkNum;
+  }
+  gBenchmarkStartTimeNs = 0;
+}
+
+void StartBenchmarkTiming(void) {
+  if (gBenchmarkStartTimeNs == 0) {
+    gBenchmarkStartTimeNs = NanoTime();
+  }
+}
+
+void StopBenchmarkTiming(uint64_t NanoTime) {
+  if (gBenchmarkStartTimeNs != 0) {
+    int64_t diff = NanoTime - gBenchmarkStartTimeNs;
+    gBenchmarkTotalTimeNs += diff;
+    gBenchmarkTotalTimeNsSquared += diff * diff;
+    if (NanoTime != 0) {
+      ++gBenchmarkNum;
+    }
+  }
+  gBenchmarkStartTimeNs = 0;
+}
+
+void StartBenchmarkTiming(uint64_t NanoTime) {
+  if (gBenchmarkStartTimeNs == 0) {
+    gBenchmarkStartTimeNs = NanoTime;
+  }
+}
+
+int main(int argc, char* argv[]) {
+  if (gBenchmarks->empty()) {
+    fprintf(stderr, "No benchmarks registered!\n");
+    exit(EXIT_FAILURE);
+  }
+
+  bool need_header = true;
+  for (auto b : *gBenchmarks) {
+    if (ShouldRun(b, argc, argv)) {
+      if (need_header) {
+        printf("%-25s %10s %10s\n", "", "iterations", "ns/op");
+        fflush(stdout);
+        need_header = false;
+      }
+      Run(b);
+    }
+  }
+
+  if (need_header) {
+    fprintf(stderr, "No matching benchmarks!\n");
+    fprintf(stderr, "Available benchmarks:\n");
+    for (auto b : *gBenchmarks) {
+      fprintf(stderr, "  %s\n", b->Name());
+    }
+    exit(EXIT_FAILURE);
+  }
+
+  return 0;
+}