1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef CHRE_WIFI_OFFLOAD_TEST_RANDOM_GENERATOR_H_
18#define CHRE_WIFI_OFFLOAD_TEST_RANDOM_GENERATOR_H_
19
20#include <cinttypes>
21#include <random>
22
23namespace wifi_offload_test {
24
25/**
26 * @class RandomGenerator A class to generate random values for any uint type:
27 *        (uint8_t, ..., uint64_t). Also supports resetting to its initial
28 *        state to be able to reproduce the same random sequence.
29 */
30class RandomGenerator {
31 public:
32  /**
33   * Default constructs a RandomGenerator object
34   */
35  RandomGenerator();
36
37  /**
38   * Resets the object to its initial state. Useful if we want to reproduce the
39   * exact same sequenct again.
40   */
41  void Reset();
42
43  /**
44   * Generates a random number of type IntType
45   *
46   * @return A random number of type IntType
47   */
48  template <typename IntType>
49  IntType get() {
50    return static_cast<IntType>(uniform_distribution_(random_engine_));
51  }
52
53 private:
54  /* The initial seed kept to use again when need to reset  */
55  std::random_device::result_type initial_seed_;
56
57  /* Standard mersenne_twister_engine */
58  std::mt19937 random_engine_;
59
60  /**
61   * Use uniform_distribution_ to transform the random unsigned int generated by
62   * random_engine_ into an uint64_t
63   */
64  std::uniform_int_distribution<uint64_t> uniform_distribution_;
65};
66
67}  // wifi_offload_test namespace
68
69#endif  // CHRE_WIFI_OFFLOAD_TEST_RANDOM_GENERATOR_H_
70