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author | Andy Hung <hunga@google.com> | 2020-10-29 02:09:57 +0000 |
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committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | 2020-10-29 02:09:57 +0000 |
commit | 6305a290a0e261dbf61354f298a799297de54360 (patch) | |
tree | 35d73359fd09cc16d1fbb857909581bad75b765e /third_party/abseil-cpp/absl/random/internal/randen_traits.h | |
parent | bdcf7c15937fa6f88b52f091024bd667d6b2b302 (diff) | |
parent | b02c729712188d3420b78a1bbb1b779544bd4427 (diff) | |
download | webrtc-6305a290a0e261dbf61354f298a799297de54360.tar.gz |
Merge "Import abseil-cpp to third_party" am: aa2897cdcb am: 2cc1e455f9 am: 4211622fc5 am: b02c729712
Original change: https://android-review.googlesource.com/c/platform/external/webrtc/+/1477956
Change-Id: I2157494054f0fdd15375163dda6ee668e2b90f0b
Diffstat (limited to 'third_party/abseil-cpp/absl/random/internal/randen_traits.h')
-rw-r--r-- | third_party/abseil-cpp/absl/random/internal/randen_traits.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/random/internal/randen_traits.h b/third_party/abseil-cpp/absl/random/internal/randen_traits.h new file mode 100644 index 0000000000..2b8bbe7383 --- /dev/null +++ b/third_party/abseil-cpp/absl/random/internal/randen_traits.h @@ -0,0 +1,63 @@ +// 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_TRAITS_H_ +#define ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ + +// HERMETIC NOTE: The randen_hwaes target must not introduce duplicate +// symbols from arbitrary system and other headers, since it may be built +// with different flags from other targets, using different levels of +// optimization, potentially introducing ODR violations. + +#include <cstddef> + +#include "absl/base/config.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace random_internal { + +// RANDen = RANDom generator or beetroots in Swiss German. +// 'Strong' (well-distributed, unpredictable, backtracking-resistant) random +// generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32. +// +// RandenTraits contains the basic algorithm traits, such as the size of the +// state, seed, sponge, etc. +struct RandenTraits { + // Size of the entire sponge / state for the randen PRNG. + static constexpr size_t kStateBytes = 256; // 2048-bit + + // Size of the 'inner' (inaccessible) part of the sponge. Larger values would + // require more frequent calls to RandenGenerate. + static constexpr size_t kCapacityBytes = 16; // 128-bit + + // Size of the default seed consumed by the sponge. + static constexpr size_t kSeedBytes = kStateBytes - kCapacityBytes; + + // Largest size for which security proofs are known. + static constexpr size_t kFeistelBlocks = 16; + + // Type-2 generalized Feistel => one round function for every two blocks. + static constexpr size_t kFeistelFunctions = kFeistelBlocks / 2; // = 8 + + // Ensures SPRP security and two full subblock diffusions. + // Must be > 4 * log2(kFeistelBlocks). + static constexpr size_t kFeistelRounds = 16 + 1; +}; + +} // namespace random_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ |