1 files changed, 57 insertions, 0 deletions
diff --git a/absl/strings/charset_benchmark.cc b/absl/strings/charset_benchmark.cc
new file mode 100644
index 00000000..bf7ae560
--- /dev/null
+++ b/absl/strings/charset_benchmark.cc
@@ -0,0 +1,57 @@
+// Copyright 2020 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 <cstdint>
+
+#include "benchmark/benchmark.h"
+#include "absl/log/check.h"
+#include "absl/strings/charset.h"
+
+namespace {
+
+absl::CharSet MakeBenchmarkMap() {
+  absl::CharSet m;
+  uint32_t x[] = {0x0, 0x1, 0x2, 0x3, 0xf, 0xe, 0xd, 0xc};
+  for (uint32_t& t : x) t *= static_cast<uint32_t>(0x11111111UL);
+  for (uint32_t i = 0; i < 256; ++i) {
+    if ((x[i / 32] >> (i % 32)) & 1) m = m | absl::CharSet::Char(i);
+  }
+  return m;
+}
+
+// Micro-benchmark for Charmap::contains.
+static void BM_Contains(benchmark::State& state) {
+  // Loop-body replicated 10 times to increase time per iteration.
+  // Argument continuously changed to avoid generating common subexpressions.
+  // Final CHECK used to discourage unwanted optimization.
+  const absl::CharSet benchmark_map = MakeBenchmarkMap();
+  unsigned char c = 0;
+  int ops = 0;
+  for (auto _ : state) {
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+    ops += benchmark_map.contains(c++);
+  }
+  CHECK_NE(ops, -1);
+}
+BENCHMARK(BM_Contains);
+
+}  // namespace