From e9324d926a9189e222741fce6e676f0944661a72 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Fri, 21 Jun 2019 13:11:42 -0700 Subject: Export of internal Abseil changes. -- 7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt : Internal change. PiperOrigin-RevId: 254454546 -- ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer : Internal changes PiperOrigin-RevId: 254451562 -- deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson : Account for subtracting unsigned values from the size of InlinedVector PiperOrigin-RevId: 254450625 -- 3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer : Add C++17's std::make_from_tuple to absl/utility/utility.h PiperOrigin-RevId: 254411573 -- 4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson : Adds benchmark for the rest of the InlinedVector public API PiperOrigin-RevId: 254408378 -- e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson : Updates the definition of InlinedVector::shrink_to_fit() to be exception safe and adds exception safety tests for it. PiperOrigin-RevId: 254401387 -- 2ea82e72b86d82d78b4e4712a63a55981b53c64b by Laramie Leavitt : Use absl::InsecureBitGen in place of std::mt19937 in tests absl/random/...distribution_test.cc PiperOrigin-RevId: 254289444 -- fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer : Internal changes PiperOrigin-RevId: 254286334 -- ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer : Internal changes PiperOrigin-RevId: 254273059 -- 6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown : Change absl::container_internal::CompressedTuple to instantiate its internal Storage class with the name of the type it's holding, rather than the name of the Tuple. This is not an externally-visible change, other than less compiler memory is used and less debug information is generated. PiperOrigin-RevId: 254269285 -- 8bd3c186bf2fc0c55d8a2dd6f28a5327502c9fba by Andy Soffer : Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for IntervalOpenOpen. PiperOrigin-RevId: 254252419 -- ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team : Do not directly use __SIZEOF_INT128__. In order to avoid linker errors when building with clang-cl (__fixunsdfti, __udivti3 and __fixunssfti are undefined), this CL uses ABSL_HAVE_INTRINSIC_INT128 which is not defined for clang-cl. PiperOrigin-RevId: 254250739 -- 89ab385cd26b34d64130bce856253aaba96d2345 by Andy Soffer : Internal changes PiperOrigin-RevId: 254242321 -- cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson : Adds benchmark for InlinedVector::reserve(size_type) PiperOrigin-RevId: 254199226 -- c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental : Import of CCTZ from GitHub. PiperOrigin-RevId: 254072387 -- c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt : Internal cleanup. PiperOrigin-RevId: 254062381 -- d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck : Update distributions.h to Abseil standards PiperOrigin-RevId: 254054946 -- d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson : Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions PiperOrigin-RevId: 254005427 -- 2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer : Initial release of Abseil Random PiperOrigin-RevId: 253999861 -- 24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson : Updates the definition of InlinedVector::assign(...)/InlinedVector::operator=(...) to new, exception-safe implementations with exception safety tests to boot PiperOrigin-RevId: 253993691 -- 5613d95f5a7e34a535cfaeadce801441e990843e by CJ Johnson : Adds benchmarks for InlinedVector::shrink_to_fit() PiperOrigin-RevId: 253989647 -- 2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team : Initial release of Abseil Random PiperOrigin-RevId: 253927497 -- bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer : Initial release of Abseil Random PiperOrigin-RevId: 253920512 -- bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt : Internal change. PiperOrigin-RevId: 253886486 -- 05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier : Don't include `winsock2.h` because it drags in `windows.h` and friends, and they define awful macros like OPAQUE, ERROR, and more. This has the potential to break abseil users. Instead we only forward declare `timeval` and require Windows users include `winsock2.h` themselves. This is both inconsistent and poor QoI, but so including 'windows.h' is bad too. PiperOrigin-RevId: 253852615 GitOrigin-RevId: 7a6ff16a85beb730c172d5d25cf1b5e1be885c56 Change-Id: Icd6aff87da26f29ec8915da856f051129987cef6 --- absl/random/internal/salted_seed_seq.h | 152 +++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 absl/random/internal/salted_seed_seq.h (limited to 'absl/random/internal/salted_seed_seq.h') diff --git a/absl/random/internal/salted_seed_seq.h b/absl/random/internal/salted_seed_seq.h new file mode 100644 index 00000000..3d16cf97 --- /dev/null +++ b/absl/random/internal/salted_seed_seq.h @@ -0,0 +1,152 @@ +// 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_SALTED_SEED_SEQ_H_ +#define ABSL_RANDOM_INTERNAL_SALTED_SEED_SEQ_H_ + +#include +#include +#include +#include +#include +#include +#include + +#include "absl/container/inlined_vector.h" +#include "absl/meta/type_traits.h" +#include "absl/random/internal/seed_material.h" +#include "absl/types/optional.h" +#include "absl/types/span.h" + +namespace absl { +namespace random_internal { + +// This class conforms to the C++ Standard "Seed Sequence" concept +// [rand.req.seedseq]. +// +// A `SaltedSeedSeq` is meant to wrap an existing seed sequence and modify +// generated sequence by mixing with extra entropy. This entropy may be +// build-dependent or process-dependent. The implementation may change to be +// have either or both kinds of entropy. If salt is not available sequence is +// not modified. +template +class SaltedSeedSeq { + public: + using inner_sequence_type = SSeq; + using result_type = typename SSeq::result_type; + + SaltedSeedSeq() : seq_(absl::make_unique()) {} + + template + SaltedSeedSeq(Iterator begin, Iterator end) + : seq_(absl::make_unique(begin, end)) {} + + template + SaltedSeedSeq(std::initializer_list il) + : SaltedSeedSeq(il.begin(), il.end()) {} + + SaltedSeedSeq(const SaltedSeedSeq& other) = delete; + SaltedSeedSeq& operator=(const SaltedSeedSeq& other) = delete; + + SaltedSeedSeq(SaltedSeedSeq&& other) = default; + SaltedSeedSeq& operator=(SaltedSeedSeq&& other) = default; + + template + void generate(RandomAccessIterator begin, RandomAccessIterator end) { + if (begin != end) { + generate_impl( + std::integral_constant{}, + begin, end); + } + } + + template + void param(OutIterator out) const { + seq_->param(out); + } + + size_t size() const { return seq_->size(); } + + private: + // The common case for generate is that it is called with iterators over a + // 32-bit value buffer. These can be reinterpreted to a uint32_t and we can + // operate on them as such. + template + void generate_impl(std::integral_constant /*is_32bit*/, + RandomAccessIterator begin, RandomAccessIterator end) { + seq_->generate(begin, end); + const uint32_t salt = absl::random_internal::GetSaltMaterial().value_or(0); + auto buffer = absl::MakeSpan(begin, end); + MixIntoSeedMaterial( + absl::MakeConstSpan(&salt, 1), + absl::MakeSpan(reinterpret_cast(buffer.data()), + buffer.size())); + } + + // The uncommon case for generate is that it is called with iterators over + // some other buffer type which is assignable from a 32-bit value. In this + // case we allocate a temporary 32-bit buffer and then copy-assign back + // to the initial inputs. + template + void generate_impl(std::integral_constant /*is_32bit*/, + RandomAccessIterator begin, RandomAccessIterator end) { + // Allocate a temporary buffer, seed, and then copy. + absl::InlinedVector data(std::distance(begin, end), 0); + generate_impl(std::integral_constant{}, data.begin(), + data.end()); + std::copy(data.begin(), data.end(), begin); + } + + // Because [rand.req.seedseq] is not copy-constructible, copy-assignable nor + // movable so we wrap it with unique pointer to be able to move SaltedSeedSeq. + std::unique_ptr seq_; +}; + +// is_salted_seed_seq indicates whether the type is a SaltedSeedSeq. +template +struct is_salted_seed_seq : public std::false_type {}; + +template +struct is_salted_seed_seq< + T, typename std::enable_if>::value>::type> + : public std::true_type {}; + +// MakeSaltedSeedSeq returns a salted variant of the seed sequence. +// When provided with an existing SaltedSeedSeq, returns the input parameter, +// otherwise constructs a new SaltedSeedSeq which embodies the original +// non-salted seed parameters. +template < + typename SSeq, // + typename EnableIf = absl::enable_if_t::value>> +SSeq MakeSaltedSeedSeq(SSeq&& seq) { + return SSeq(std::forward(seq)); +} + +template < + typename SSeq, // + typename EnableIf = absl::enable_if_t::value>> +SaltedSeedSeq::type> MakeSaltedSeedSeq(SSeq&& seq) { + using sseq_type = typename std::decay::type; + using result_type = typename sseq_type::result_type; + + absl::InlinedVector data; + seq.param(std::back_inserter(data)); + return SaltedSeedSeq(data.begin(), data.end()); +} + +} // namespace random_internal +} // namespace absl + +#endif // ABSL_RANDOM_INTERNAL_SALTED_SEED_SEQ_H_ -- cgit v1.2.3