1 // Copyright 2018 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 "absl/strings/internal/ostringstream.h"
16
17 #include <sstream>
18 #include <string>
19
20 #include "benchmark/benchmark.h"
21
22 namespace {
23
24 enum StringType {
25 kNone,
26 kStdString,
27 };
28
29 // Benchmarks for std::ostringstream.
30 template <StringType kOutput>
BM_StdStream(benchmark::State & state)31 void BM_StdStream(benchmark::State& state) {
32 const int num_writes = state.range(0);
33 const int bytes_per_write = state.range(1);
34 const std::string payload(bytes_per_write, 'x');
35 for (auto _ : state) {
36 std::ostringstream strm;
37 benchmark::DoNotOptimize(strm);
38 for (int i = 0; i != num_writes; ++i) {
39 strm << payload;
40 }
41 switch (kOutput) {
42 case kNone: {
43 break;
44 }
45 case kStdString: {
46 std::string s = strm.str();
47 benchmark::DoNotOptimize(s);
48 break;
49 }
50 }
51 }
52 }
53
54 // Create the stream, optionally write to it, then destroy it.
55 BENCHMARK_TEMPLATE(BM_StdStream, kNone)
56 ->ArgPair(0, 0)
57 ->ArgPair(1, 16) // 16 bytes is small enough for SSO
58 ->ArgPair(1, 256) // 256 bytes requires heap allocation
59 ->ArgPair(1024, 256);
60 // Create the stream, write to it, get std::string out, then destroy.
61 BENCHMARK_TEMPLATE(BM_StdStream, kStdString)
62 ->ArgPair(1, 16) // 16 bytes is small enough for SSO
63 ->ArgPair(1, 256) // 256 bytes requires heap allocation
64 ->ArgPair(1024, 256);
65
66 // Benchmarks for OStringStream.
67 template <StringType kOutput>
BM_CustomStream(benchmark::State & state)68 void BM_CustomStream(benchmark::State& state) {
69 const int num_writes = state.range(0);
70 const int bytes_per_write = state.range(1);
71 const std::string payload(bytes_per_write, 'x');
72 for (auto _ : state) {
73 std::string out;
74 absl::strings_internal::OStringStream strm(&out);
75 benchmark::DoNotOptimize(strm);
76 for (int i = 0; i != num_writes; ++i) {
77 strm << payload;
78 }
79 switch (kOutput) {
80 case kNone: {
81 break;
82 }
83 case kStdString: {
84 std::string s = out;
85 benchmark::DoNotOptimize(s);
86 break;
87 }
88 }
89 }
90 }
91
92 // Create the stream, optionally write to it, then destroy it.
93 BENCHMARK_TEMPLATE(BM_CustomStream, kNone)
94 ->ArgPair(0, 0)
95 ->ArgPair(1, 16) // 16 bytes is small enough for SSO
96 ->ArgPair(1, 256) // 256 bytes requires heap allocation
97 ->ArgPair(1024, 256);
98 // Create the stream, write to it, get std::string out, then destroy.
99 // It's not useful in practice to extract std::string from OStringStream; we
100 // measure it for completeness.
101 BENCHMARK_TEMPLATE(BM_CustomStream, kStdString)
102 ->ArgPair(1, 16) // 16 bytes is small enough for SSO
103 ->ArgPair(1, 256) // 256 bytes requires heap allocation
104 ->ArgPair(1024, 256);
105
106 } // namespace
107