| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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. |
| |
| #ifndef IMPALA_TESTUTIL_RAND_UTIL_H_ |
| #define IMPALA_TESTUTIL_RAND_UTIL_H_ |
| |
| #include <cstdint> |
| #include <cstdlib> |
| #include <random> |
| |
| #include "common/logging.h" |
| |
| namespace impala { |
| |
| /// Test helpers for randomised tests. |
| class RandTestUtil { |
| public: |
| /// Seed 'rng' with a seed either from the environment variable 'env_var' or the |
| /// random device of the platform. |
| template <typename RandomEngine> |
| static void SeedRng(const char* env_var, RandomEngine* rng) { |
| const char* seed_str = getenv(env_var); |
| int64_t seed; |
| if (seed_str != nullptr) { |
| seed = atoi(seed_str); |
| } else { |
| seed = std::random_device()(); |
| } |
| LOG(INFO) << "Random seed (overridable with " << env_var << "): " << seed; |
| rng->seed(seed); |
| } |
| |
| /// Create 'num_threads' rngs, seeded using 'seed_rng'. Used when we want each thread |
| /// to have its own RNG (since they are not thread-safe). |
| static vector<std::mt19937> CreateThreadLocalRngs( |
| int num_threads, std::mt19937* seed_rng) { |
| vector<std::mt19937> rngs(num_threads); |
| for (std::mt19937& rng : rngs) rng.seed((*seed_rng)()); |
| return rngs; |
| } |
| }; |
| } |
| |
| #endif |