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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);
template <typename... Chunks>
void BM_StrAppendImpl(benchmark::State& state, size_t total_bytes,
Chunks... chunks) {
for (auto s : state) {
std::string result;
while (result.size() < total_bytes) {
absl::StrAppend(&result, chunks...);
benchmark::DoNotOptimize(result);
}
}
}
void BM_StrAppend(benchmark::State& state) {
const int total_bytes = state.range(0);
const int chunks_at_a_time = state.range(1);
const absl::string_view kChunk = "0123456789";
switch (chunks_at_a_time) {
case 1:
return BM_StrAppendImpl(state, total_bytes, kChunk);
case 2:
return BM_StrAppendImpl(state, total_bytes, kChunk, kChunk);
case 4:
return BM_StrAppendImpl(state, total_bytes, kChunk, kChunk, kChunk,
kChunk);
case 8:
return BM_StrAppendImpl(state, total_bytes, kChunk, kChunk, kChunk,
kChunk, kChunk, kChunk, kChunk, kChunk);
default:
std::abort();
}
}
template <typename B>
void StrAppendConfig(B* benchmark) {
for (int bytes : {10, 100, 1000, 10000}) {
for (int chunks : {1, 2, 4, 8}) {
// Only add the ones that divide properly. Otherwise we are over counting.
if (bytes % (10 * chunks) == 0) {
benchmark->Args({bytes, chunks});
}
}
}
}
BENCHMARK(BM_StrAppend)->Apply(StrAppendConfig);
} // namespace
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