Abseil Common Libraries (C++) (grcp 依赖)
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100 lines
3.2 KiB
100 lines
3.2 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#ifndef ABSL_RANDOM_INTERNAL_RANDEN_H_ |
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#define ABSL_RANDOM_INTERNAL_RANDEN_H_ |
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#include <cstddef> |
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#include "absl/random/internal/platform.h" |
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#include "absl/random/internal/randen_hwaes.h" |
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#include "absl/random/internal/randen_slow.h" |
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#include "absl/random/internal/randen_traits.h" |
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namespace absl { |
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namespace random_internal { |
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// RANDen = RANDom generator or beetroots in Swiss German. |
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// 'Strong' (well-distributed, unpredictable, backtracking-resistant) random |
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// generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32. |
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// |
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// Randen implements the basic state manipulation methods. |
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class Randen { |
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public: |
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static constexpr size_t kStateBytes = RandenTraits::kStateBytes; |
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static constexpr size_t kCapacityBytes = RandenTraits::kCapacityBytes; |
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static constexpr size_t kSeedBytes = RandenTraits::kSeedBytes; |
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~Randen() = default; |
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Randen(); |
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// Generate updates the randen sponge. The outer portion of the sponge |
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// (kCapacityBytes .. kStateBytes) may be consumed as PRNG state. |
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template <typename T, size_t N> |
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void Generate(T (&state)[N]) const { |
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static_assert(N * sizeof(T) == kStateBytes, |
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"Randen::Generate() requires kStateBytes of state"); |
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#if ABSL_RANDOM_INTERNAL_AES_DISPATCH |
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// HW AES Dispatch. |
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if (has_crypto_) { |
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RandenHwAes::Generate(keys_, state); |
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} else { |
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RandenSlow::Generate(keys_, state); |
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} |
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#elif ABSL_HAVE_ACCELERATED_AES |
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// HW AES is enabled. |
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RandenHwAes::Generate(keys_, state); |
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#else |
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// HW AES is disabled. |
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RandenSlow::Generate(keys_, state); |
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#endif |
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} |
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// Absorb incorporates additional seed material into the randen sponge. After |
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// absorb returns, Generate must be called before the state may be consumed. |
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template <typename S, size_t M, typename T, size_t N> |
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void Absorb(const S (&seed)[M], T (&state)[N]) const { |
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static_assert(M * sizeof(S) == RandenTraits::kSeedBytes, |
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"Randen::Absorb() requires kSeedBytes of seed"); |
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static_assert(N * sizeof(T) == RandenTraits::kStateBytes, |
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"Randen::Absorb() requires kStateBytes of state"); |
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#if ABSL_RANDOM_INTERNAL_AES_DISPATCH |
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// HW AES Dispatch. |
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if (has_crypto_) { |
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RandenHwAes::Absorb(seed, state); |
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} else { |
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RandenSlow::Absorb(seed, state); |
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} |
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#elif ABSL_HAVE_ACCELERATED_AES |
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// HW AES is enabled. |
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RandenHwAes::Absorb(seed, state); |
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#else |
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// HW AES is disabled. |
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RandenSlow::Absorb(seed, state); |
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#endif |
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} |
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private: |
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const void* keys_; |
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#if ABSL_RANDOM_INTERNAL_AES_DISPATCH |
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bool has_crypto_; |
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#endif |
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}; |
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} // namespace random_internal |
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} // namespace absl |
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#endif // ABSL_RANDOM_INTERNAL_RANDEN_H_
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