1 // Copyright 2020 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <cstdint>
16
17 #include "benchmark/benchmark.h"
18 #include "absl/log/check.h"
19 #include "absl/strings/charset.h"
20
21 namespace {
22
MakeBenchmarkMap()23 absl::CharSet MakeBenchmarkMap() {
24 absl::CharSet m;
25 uint32_t x[] = {0x0, 0x1, 0x2, 0x3, 0xf, 0xe, 0xd, 0xc};
26 for (uint32_t& t : x) t *= static_cast<uint32_t>(0x11111111UL);
27 for (uint32_t i = 0; i < 256; ++i) {
28 if ((x[i / 32] >> (i % 32)) & 1) m = m | absl::CharSet::Char(i);
29 }
30 return m;
31 }
32
33 // Micro-benchmark for Charmap::contains.
BM_Contains(benchmark::State & state)34 static void BM_Contains(benchmark::State& state) {
35 // Loop-body replicated 10 times to increase time per iteration.
36 // Argument continuously changed to avoid generating common subexpressions.
37 // Final CHECK used to discourage unwanted optimization.
38 const absl::CharSet benchmark_map = MakeBenchmarkMap();
39 unsigned char c = 0;
40 int ops = 0;
41 for (auto _ : state) {
42 ops += benchmark_map.contains(c++);
43 ops += benchmark_map.contains(c++);
44 ops += benchmark_map.contains(c++);
45 ops += benchmark_map.contains(c++);
46 ops += benchmark_map.contains(c++);
47 ops += benchmark_map.contains(c++);
48 ops += benchmark_map.contains(c++);
49 ops += benchmark_map.contains(c++);
50 ops += benchmark_map.contains(c++);
51 ops += benchmark_map.contains(c++);
52 }
53 CHECK_NE(ops, -1);
54 }
55 BENCHMARK(BM_Contains);
56
57 } // namespace
58