1//===- FuzzerRandom.h - Internal header for the Fuzzer ----------*- C++ -* ===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// fuzzer::Random
9//===----------------------------------------------------------------------===//
10
11#ifndef LLVM_FUZZER_RANDOM_H
12#define LLVM_FUZZER_RANDOM_H
13
14#include <random>
15
16namespace fuzzer {
17class Random : public std::minstd_rand {
18 public:
19 Random(unsigned int seed) : std::minstd_rand(seed) {}
20 result_type operator()() { return this->std::minstd_rand::operator()(); }
21 template <typename T>
22 typename std::enable_if<std::is_integral<T>::value, T>::type Rand() {
23 return static_cast<T>(this->operator()());
24 }
25 size_t RandBool() { return this->operator()() % 2; }
26 size_t SkewTowardsLast(size_t n) {
27 size_t T = this->operator()(n: n * n);
28 size_t Res = static_cast<size_t>(sqrt(x: T));
29 return Res;
30 }
31 template <typename T>
32 typename std::enable_if<std::is_integral<T>::value, T>::type operator()(T n) {
33 return n ? Rand<T>() % n : 0;
34 }
35 template <typename T>
36 typename std::enable_if<std::is_integral<T>::value, T>::type
37 operator()(T From, T To) {
38 assert(From < To);
39 auto RangeSize = static_cast<unsigned long long>(To) -
40 static_cast<unsigned long long>(From) + 1;
41 return static_cast<T>(this->operator()(n: RangeSize) + From);
42 }
43};
44
45} // namespace fuzzer
46
47#endif // LLVM_FUZZER_RANDOM_H
48