llvm/llvm/include/llvm/FuzzMutate/Random.h

//===--- Random.h - Utilities for random sampling -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Utilities for random sampling.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_FUZZMUTATE_RANDOM_H
#define LLVM_FUZZMUTATE_RANDOM_H

#include "llvm/Support/raw_ostream.h"
#include <random>
namespace llvm {

/// Return a uniformly distributed random value between \c Min and \c Max
template <typename T, typename GenT> T uniform(GenT &Gen, T Min, T Max) { … }

/// Return a uniformly distributed random value of type \c T
template <typename T, typename GenT> T uniform(GenT &Gen) { … }

/// Randomly selects an item by sampling into a set with an unknown number of
/// elements, which may each be weighted to be more likely choices.
template <typename T, typename GenT> class ReservoirSampler { … };

template <typename GenT, typename RangeT,
          typename ElT = std::remove_reference_t<
              decltype(*std::begin(std::declval<RangeT>()))>>
ReservoirSampler<ElT, GenT> makeSampler(GenT &RandGen, RangeT &&Items) { … }

template <typename GenT, typename T>
ReservoirSampler<T, GenT> makeSampler(GenT &RandGen, const T &Item,
                                      uint64_t Weight) { … }

template <typename T, typename GenT>
ReservoirSampler<T, GenT> makeSampler(GenT &RandGen) { … }

} // namespace llvm

#endif // LLVM_FUZZMUTATE_RANDOM_H