chromium/third_party/abseil-cpp/absl/random/internal/randen_engine.h

// Copyright 2017 The Abseil Authors.
//
// Licensed 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
//
//      https://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 ABSL_RANDOM_INTERNAL_RANDEN_ENGINE_H_
#define ABSL_RANDOM_INTERNAL_RANDEN_ENGINE_H_

#include <algorithm>
#include <cinttypes>
#include <cstdlib>
#include <iostream>
#include <iterator>
#include <limits>
#include <type_traits>

#include "absl/base/internal/endian.h"
#include "absl/meta/type_traits.h"
#include "absl/random/internal/iostream_state_saver.h"
#include "absl/random/internal/randen.h"

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace random_internal {

// Deterministic pseudorandom byte generator with backtracking resistance
// (leaking the state does not compromise prior outputs). Based on Reverie
// (see "A Robust and Sponge-Like PRNG with Improved Efficiency") instantiated
// with an improved Simpira-like permutation.
// Returns values of type "T" (must be a built-in unsigned integer type).
//
// RANDen = RANDom generator or beetroots in Swiss High German.
// 'Strong' (well-distributed, unpredictable, backtracking-resistant) random
// generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32.
template <typename T>
class alignas(8) randen_engine { … };

}  // namespace random_internal
ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_RANDOM_INTERNAL_RANDEN_ENGINE_H_