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 <cmath>
15#include <random>
16
17namespace fuzzer {
18class Random : public std::minstd_rand {
19 public:
20 Random(unsigned int seed) : std::minstd_rand(seed) {}
21 result_type operator()() { return this->std::minstd_rand::operator()(); }
22 template <typename T>
23 typename std::enable_if<std::is_integral<T>::value, T>::type Rand() {
24 return static_cast<T>(this->operator()());
25 }
26 size_t RandBool() { return this->operator()() % 2; }
27 size_t SkewTowardsLast(size_t n) {
28 size_t T = this->operator()(n: n * n);
29 size_t Res = static_cast<size_t>(sqrt(x: T));
30 return Res;
31 }
32 template <typename T>
33 typename std::enable_if<std::is_integral<T>::value, T>::type operator()(T n) {
34 return n ? Rand<T>() % n : 0;
35 }
36 template <typename T>
37 typename std::enable_if<std::is_integral<T>::value, T>::type
38 operator()(T From, T To) {
39 assert(From < To);
40 auto RangeSize = static_cast<unsigned long long>(To) -
41 static_cast<unsigned long long>(From) + 1;
42 return static_cast<T>(this->operator()(n: RangeSize) + From);
43 }
44};
45
46} // namespace fuzzer
47
48#endif // LLVM_FUZZER_RANDOM_H
49