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to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
70 lines
2.3 KiB
C++
70 lines
2.3 KiB
C++
//==- llvm/Support/RandomNumberGenerator.h - RNG for diversity ---*- C++ -*-==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines an abstraction for deterministic random number
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// generation (RNG). Note that the current implementation is not
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// cryptographically secure as it uses the C++11 <random> facilities.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_RANDOMNUMBERGENERATOR_H_
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#define LLVM_SUPPORT_RANDOMNUMBERGENERATOR_H_
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/DataTypes.h" // Needed for uint64_t on Windows.
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#include <random>
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#include <system_error>
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namespace llvm {
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class StringRef;
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/// A random number generator.
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///
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/// Instances of this class should not be shared across threads. The
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/// seed should be set by passing the -rng-seed=<uint64> option. Use
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/// Module::createRNG to create a new RNG instance for use with that
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/// module.
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class RandomNumberGenerator {
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// 64-bit Mersenne Twister by Matsumoto and Nishimura, 2000
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// http://en.cppreference.com/w/cpp/numeric/random/mersenne_twister_engine
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// This RNG is deterministically portable across C++11
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// implementations.
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using generator_type = std::mt19937_64;
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public:
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using result_type = generator_type::result_type;
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/// Returns a random number in the range [0, Max).
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result_type operator()();
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static constexpr result_type min() { return generator_type::min(); }
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static constexpr result_type max() { return generator_type::max(); }
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private:
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/// Seeds and salts the underlying RNG engine.
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///
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/// This constructor should not be used directly. Instead use
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/// Module::createRNG to create a new RNG salted with the Module ID.
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RandomNumberGenerator(StringRef Salt);
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generator_type Generator;
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// Noncopyable.
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RandomNumberGenerator(const RandomNumberGenerator &other) = delete;
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RandomNumberGenerator &operator=(const RandomNumberGenerator &other) = delete;
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friend class Module;
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};
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// Get random vector of specified size
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std::error_code getRandomBytes(void *Buffer, size_t Size);
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}
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#endif
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