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Diffstat (limited to 'third_party/abseil_cpp/absl/random/seed_sequences.h')
| -rw-r--r-- | third_party/abseil_cpp/absl/random/seed_sequences.h | 110 |
1 files changed, 0 insertions, 110 deletions
diff --git a/third_party/abseil_cpp/absl/random/seed_sequences.h b/third_party/abseil_cpp/absl/random/seed_sequences.h deleted file mode 100644 index ff1340cc8eed..000000000000 --- a/third_party/abseil_cpp/absl/random/seed_sequences.h +++ /dev/null @@ -1,110 +0,0 @@ -// 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. -// -// ----------------------------------------------------------------------------- -// File: seed_sequences.h -// ----------------------------------------------------------------------------- -// -// This header contains utilities for creating and working with seed sequences -// conforming to [rand.req.seedseq]. In general, direct construction of seed -// sequences is discouraged, but use-cases for construction of identical bit -// generators (using the same seed sequence) may be helpful (e.g. replaying a -// simulation whose state is derived from variates of a bit generator). - -#ifndef ABSL_RANDOM_SEED_SEQUENCES_H_ -#define ABSL_RANDOM_SEED_SEQUENCES_H_ - -#include <iterator> -#include <random> - -#include "absl/random/internal/salted_seed_seq.h" -#include "absl/random/internal/seed_material.h" -#include "absl/random/seed_gen_exception.h" -#include "absl/types/span.h" - -namespace absl { -ABSL_NAMESPACE_BEGIN - -// ----------------------------------------------------------------------------- -// absl::SeedSeq -// ----------------------------------------------------------------------------- -// -// `absl::SeedSeq` constructs a seed sequence according to [rand.req.seedseq] -// for use within bit generators. `absl::SeedSeq`, unlike `std::seed_seq` -// additionally salts the generated seeds with extra implementation-defined -// entropy. For that reason, you can use `absl::SeedSeq` in combination with -// standard library bit generators (e.g. `std::mt19937`) to introduce -// non-determinism in your seeds. -// -// Example: -// -// absl::SeedSeq my_seed_seq({a, b, c}); -// std::mt19937 my_bitgen(my_seed_seq); -// -using SeedSeq = random_internal::SaltedSeedSeq<std::seed_seq>; - -// ----------------------------------------------------------------------------- -// absl::CreateSeedSeqFrom(bitgen*) -// ----------------------------------------------------------------------------- -// -// Constructs a seed sequence conforming to [rand.req.seedseq] using variates -// produced by a provided bit generator. -// -// You should generally avoid direct construction of seed sequences, but -// use-cases for reuse of a seed sequence to construct identical bit generators -// may be helpful (eg. replaying a simulation whose state is derived from bit -// generator values). -// -// If bitgen == nullptr, then behavior is undefined. -// -// Example: -// -// absl::BitGen my_bitgen; -// auto seed_seq = absl::CreateSeedSeqFrom(&my_bitgen); -// absl::BitGen new_engine(seed_seq); // derived from my_bitgen, but not -// // correlated. -// -template <typename URBG> -SeedSeq CreateSeedSeqFrom(URBG* urbg) { - SeedSeq::result_type - seed_material[random_internal::kEntropyBlocksNeeded]; - - if (!random_internal::ReadSeedMaterialFromURBG( - urbg, absl::MakeSpan(seed_material))) { - random_internal::ThrowSeedGenException(); - } - return SeedSeq(std::begin(seed_material), std::end(seed_material)); -} - -// ----------------------------------------------------------------------------- -// absl::MakeSeedSeq() -// ----------------------------------------------------------------------------- -// -// Constructs an `absl::SeedSeq` salting the generated values using -// implementation-defined entropy. The returned sequence can be used to create -// equivalent bit generators correlated using this sequence. -// -// Example: -// -// auto my_seed_seq = absl::MakeSeedSeq(); -// std::mt19937 rng1(my_seed_seq); -// std::mt19937 rng2(my_seed_seq); -// EXPECT_EQ(rng1(), rng2()); -// -SeedSeq MakeSeedSeq(); - -ABSL_NAMESPACE_END -} // namespace absl - -#endif // ABSL_RANDOM_SEED_SEQUENCES_H_ |