libcxx/benchmarks/random.bench.cpp

   1 //===----------------------------------------------------------------------===//
   2 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   3 // See https://llvm.org/LICENSE.txt for license information.
   4 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   5 //
   6 //===----------------------------------------------------------------------===//
   7
   8 #include <algorithm>
   9 #include <array>
  10 #include <cstddef>
  11 #include <functional>
  12 #include <random>
  13
  14 #include "benchmark/benchmark.h"
  15
  16 constexpr std::size_t MAX_BUFFER_LEN = 256;
  17 constexpr std::size_t MAX_SEED_LEN   = 16;
  18
  19 static void BM_SeedSeq_Generate(benchmark::State& state) {
  20   std::array<std::uint32_t, MAX_BUFFER_LEN> buffer;
  21   std::array<std::uint32_t, MAX_SEED_LEN> seeds;
  22   {
  23     std::random_device rd;
  24     std::generate(std::begin(seeds), std::begin(seeds) + state.range(0), [&]() { return rd(); });
  25   }
  26   std::seed_seq seed(std::begin(seeds), std::begin(seeds) + state.range(0));
  27   for (auto _ : state) {
  28     seed.generate(std::begin(buffer), std::begin(buffer) + state.range(1));
  29   }
  30 }
  31 BENCHMARK(BM_SeedSeq_Generate)->Ranges({{1, MAX_SEED_LEN}, {1, MAX_BUFFER_LEN}});
  32
  33 BENCHMARK_MAIN();