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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
//
// 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 "absl/strings/internal/ostringstream.h"
#include <sstream>
#include <string>
#include "benchmark/benchmark.h"
namespace {
enum StringType {
kNone,
kStdString,
};
// Benchmarks for std::ostringstream.
template <StringType kOutput>
void BM_StdStream(benchmark::State& state) {
const int num_writes = state.range(0);
const int bytes_per_write = state.range(1);
const std::string payload(bytes_per_write, 'x');
for (auto _ : state) {
std::ostringstream strm;
benchmark::DoNotOptimize(strm);
for (int i = 0; i != num_writes; ++i) {
strm << payload;
}
switch (kOutput) {
case kNone: {
break;
}
case kStdString: {
std::string s = strm.str();
benchmark::DoNotOptimize(s);
break;
}
}
}
}
// Create the stream, optionally write to it, then destroy it.
BENCHMARK_TEMPLATE(BM_StdStream, kNone)
->ArgPair(0, 0)
->ArgPair(1, 16) // 16 bytes is small enough for SSO
->ArgPair(1, 256) // 256 bytes requires heap allocation
->ArgPair(1024, 256);
// Create the stream, write to it, get std::string out, then destroy.
BENCHMARK_TEMPLATE(BM_StdStream, kStdString)
->ArgPair(1, 16) // 16 bytes is small enough for SSO
->ArgPair(1, 256) // 256 bytes requires heap allocation
->ArgPair(1024, 256);
// Benchmarks for OStringStream.
template <StringType kOutput>
void BM_CustomStream(benchmark::State& state) {
const int num_writes = state.range(0);
const int bytes_per_write = state.range(1);
const std::string payload(bytes_per_write, 'x');
for (auto _ : state) {
std::string out;
absl::strings_internal::OStringStream strm(&out);
benchmark::DoNotOptimize(strm);
for (int i = 0; i != num_writes; ++i) {
strm << payload;
}
switch (kOutput) {
case kNone: {
break;
}
case kStdString: {
std::string s = out;
benchmark::DoNotOptimize(s);
break;
}
}
}
}
// Create the stream, optionally write to it, then destroy it.
BENCHMARK_TEMPLATE(BM_CustomStream, kNone)
->ArgPair(0, 0)
->ArgPair(1, 16) // 16 bytes is small enough for SSO
->ArgPair(1, 256) // 256 bytes requires heap allocation
->ArgPair(1024, 256);
// Create the stream, write to it, get std::string out, then destroy.
// It's not useful in practice to extract std::string from OStringStream; we
// measure it for completeness.
BENCHMARK_TEMPLATE(BM_CustomStream, kStdString)
->ArgPair(1, 16) // 16 bytes is small enough for SSO
->ArgPair(1, 256) // 256 bytes requires heap allocation
->ArgPair(1024, 256);
} // namespace
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