| // 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_replace.h" |
| |
| #include <cstring> |
| #include <string> |
| |
| #include "benchmark/benchmark.h" |
| #include "absl/base/internal/raw_logging.h" |
| |
| namespace { |
| |
| std::string* big_string; |
| std::string* after_replacing_the; |
| std::string* after_replacing_many; |
| |
| struct Replacement { |
| const char* needle; |
| const char* replacement; |
| } replacements[] = { |
| {"the", "box"}, // |
| {"brown", "quick"}, // |
| {"jumped", "liquored"}, // |
| {"dozen", "brown"}, // |
| {"lazy", "pack"}, // |
| {"liquor", "shakes"}, // |
| }; |
| |
| // Here, we set up a string for use in global-replace benchmarks. |
| // We started with a million blanks, and then deterministically insert |
| // 10,000 copies each of two pangrams. The result is a string that is |
| // 40% blank space and 60% these words. 'the' occurs 18,247 times and |
| // all the substitutions together occur 49,004 times. |
| // |
| // We then create "after_replacing_the" to be a string that is a result of |
| // replacing "the" with "box" in big_string. |
| // |
| // And then we create "after_replacing_many" to be a string that is result |
| // of preferring several substitutions. |
| void SetUpStrings() { |
| if (big_string == nullptr) { |
| size_t r = 0; |
| big_string = new std::string(1000 * 1000, ' '); |
| for (std::string phrase : {"the quick brown fox jumped over the lazy dogs", |
| "pack my box with the five dozen liquor jugs"}) { |
| for (int i = 0; i < 10 * 1000; ++i) { |
| r = r * 237 + 41; // not very random. |
| memcpy(&(*big_string)[r % (big_string->size() - phrase.size())], |
| phrase.data(), phrase.size()); |
| } |
| } |
| // big_string->resize(50); |
| // OK, we've set up the std::string, now let's set up expectations - first by |
| // just replacing "the" with "box" |
| after_replacing_the = new std::string(*big_string); |
| for (size_t pos = 0; |
| (pos = after_replacing_the->find("the", pos)) != std::string::npos;) { |
| memcpy(&(*after_replacing_the)[pos], "box", 3); |
| } |
| // And then with all the replacements. |
| after_replacing_many = new std::string(*big_string); |
| for (size_t pos = 0;;) { |
| size_t next_pos = static_cast<size_t>(-1); |
| const char* needle_string = nullptr; |
| const char* replacement_string = nullptr; |
| for (const auto& r : replacements) { |
| auto needlepos = after_replacing_many->find(r.needle, pos); |
| if (needlepos != std::string::npos && needlepos < next_pos) { |
| next_pos = needlepos; |
| needle_string = r.needle; |
| replacement_string = r.replacement; |
| } |
| } |
| if (next_pos > after_replacing_many->size()) break; |
| after_replacing_many->replace(next_pos, strlen(needle_string), |
| replacement_string); |
| next_pos += strlen(replacement_string); |
| pos = next_pos; |
| } |
| } |
| } |
| |
| void BM_StrReplaceAllOneReplacement(benchmark::State& state) { |
| SetUpStrings(); |
| std::string src = *big_string; |
| for (auto _ : state) { |
| std::string dest = absl::StrReplaceAll(src, {{"the", "box"}}); |
| ABSL_RAW_CHECK(dest == *after_replacing_the, |
| "not benchmarking intended behavior"); |
| } |
| } |
| BENCHMARK(BM_StrReplaceAllOneReplacement); |
| |
| void BM_StrReplaceAll(benchmark::State& state) { |
| SetUpStrings(); |
| std::string src = *big_string; |
| for (auto _ : state) { |
| std::string dest = absl::StrReplaceAll(src, {{"the", "box"}, |
| {"brown", "quick"}, |
| {"jumped", "liquored"}, |
| {"dozen", "brown"}, |
| {"lazy", "pack"}, |
| {"liquor", "shakes"}}); |
| ABSL_RAW_CHECK(dest == *after_replacing_many, |
| "not benchmarking intended behavior"); |
| } |
| } |
| BENCHMARK(BM_StrReplaceAll); |
| |
| } // namespace |