Add 'third_party/abseil_cpp/' from commit '768eb2ca28'

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54be
git-subtree-split: 768eb2ca28

third_party/abseil_cpp/absl/strings/str_cat_benchmark.cc

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+// Copyright 2018 The Abseil Authors.
+//
+// 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
+//
+//      https://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 "absl/strings/str_cat.h"
+
+#include <cstdint>
+#include <string>
+
+#include "benchmark/benchmark.h"
+#include "absl/strings/substitute.h"
+
+namespace {
+
+const char kStringOne[] = "Once Upon A Time, ";
+const char kStringTwo[] = "There was a string benchmark";
+
+// We want to include negative numbers in the benchmark, so this function
+// is used to count 0, 1, -1, 2, -2, 3, -3, ...
+inline int IncrementAlternatingSign(int i) {
+  return i > 0 ? -i : 1 - i;
+}
+
+void BM_Sum_By_StrCat(benchmark::State& state) {
+  int i = 0;
+  char foo[100];
+  for (auto _ : state) {
+    // NOLINTNEXTLINE(runtime/printf)
+    strcpy(foo, absl::StrCat(kStringOne, i, kStringTwo, i * 65536ULL).c_str());
+    int sum = 0;
+    for (char* f = &foo[0]; *f != 0; ++f) {
+      sum += *f;
+    }
+    benchmark::DoNotOptimize(sum);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_Sum_By_StrCat);
+
+void BM_StrCat_By_snprintf(benchmark::State& state) {
+  int i = 0;
+  char on_stack[1000];
+  for (auto _ : state) {
+    snprintf(on_stack, sizeof(on_stack), "%s %s:%d", kStringOne, kStringTwo, i);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_StrCat_By_snprintf);
+
+void BM_StrCat_By_Strings(benchmark::State& state) {
+  int i = 0;
+  for (auto _ : state) {
+    std::string result =
+        std::string(kStringOne) + " " + kStringTwo + ":" + absl::StrCat(i);
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_StrCat_By_Strings);
+
+void BM_StrCat_By_StringOpPlus(benchmark::State& state) {
+  int i = 0;
+  for (auto _ : state) {
+    std::string result = kStringOne;
+    result += " ";
+    result += kStringTwo;
+    result += ":";
+    result += absl::StrCat(i);
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_StrCat_By_StringOpPlus);
+
+void BM_StrCat_By_StrCat(benchmark::State& state) {
+  int i = 0;
+  for (auto _ : state) {
+    std::string result = absl::StrCat(kStringOne, " ", kStringTwo, ":", i);
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_StrCat_By_StrCat);
+
+void BM_HexCat_By_StrCat(benchmark::State& state) {
+  int i = 0;
+  for (auto _ : state) {
+    std::string result =
+        absl::StrCat(kStringOne, " ", absl::Hex(int64_t{i} + 0x10000000));
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_HexCat_By_StrCat);
+
+void BM_HexCat_By_Substitute(benchmark::State& state) {
+  int i = 0;
+  for (auto _ : state) {
+    std::string result = absl::Substitute(
+        "$0 $1", kStringOne, reinterpret_cast<void*>(int64_t{i} + 0x10000000));
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_HexCat_By_Substitute);
+
+void BM_FloatToString_By_StrCat(benchmark::State& state) {
+  int i = 0;
+  float foo = 0.0f;
+  for (auto _ : state) {
+    std::string result = absl::StrCat(foo += 1.001f, " != ", int64_t{i});
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_FloatToString_By_StrCat);
+
+void BM_DoubleToString_By_SixDigits(benchmark::State& state) {
+  int i = 0;
+  double foo = 0.0;
+  for (auto _ : state) {
+    std::string result =
+        absl::StrCat(absl::SixDigits(foo += 1.001), " != ", int64_t{i});
+    benchmark::DoNotOptimize(result);
+    i = IncrementAlternatingSign(i);
+  }
+}
+BENCHMARK(BM_DoubleToString_By_SixDigits);
+
+}  // namespace