Built motion from commit 6a09e18b.|2.6.11

[motion2.git] / legacy-libs / grpc-cloned / deps / grpc / third_party / abseil-cpp / absl / random / internal / nonsecure_base.h

diff --git a/legacy-libs/grpc-cloned/deps/grpc/third_party/abseil-cpp/absl/random/internal/nonsecure_base.h b/legacy-libs/grpc-cloned/deps/grpc/third_party/abseil-cpp/absl/random/internal/nonsecure_base.h
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+// 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_NONSECURE_BASE_H_
+#define ABSL_RANDOM_INTERNAL_NONSECURE_BASE_H_
+
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <iterator>
+#include <random>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#include "absl/base/macros.h"
+#include "absl/meta/type_traits.h"
+#include "absl/random/internal/pool_urbg.h"
+#include "absl/random/internal/salted_seed_seq.h"
+#include "absl/random/internal/seed_material.h"
+#include "absl/types/optional.h"
+#include "absl/types/span.h"
+
+namespace absl {
+namespace random_internal {
+
+// Each instance of NonsecureURBGBase<URBG> will be seeded by variates produced
+// by a thread-unique URBG-instance.
+template <typename URBG>
+class NonsecureURBGBase {
+ public:
+  using result_type = typename URBG::result_type;
+
+  // Default constructor
+  NonsecureURBGBase() : urbg_(ConstructURBG()) {}
+
+  // Copy disallowed, move allowed.
+  NonsecureURBGBase(const NonsecureURBGBase&) = delete;
+  NonsecureURBGBase& operator=(const NonsecureURBGBase&) = delete;
+  NonsecureURBGBase(NonsecureURBGBase&&) = default;
+  NonsecureURBGBase& operator=(NonsecureURBGBase&&) = default;
+
+  // Constructor using a seed
+  template <class SSeq, typename = typename absl::enable_if_t<
+                            !std::is_same<SSeq, NonsecureURBGBase>::value>>
+  explicit NonsecureURBGBase(SSeq&& seq)
+      : urbg_(ConstructURBG(std::forward<SSeq>(seq))) {}
+
+  // Note: on MSVC, min() or max() can be interpreted as MIN() or MAX(), so we
+  // enclose min() or max() in parens as (min)() and (max)().
+  // Additionally, clang-format requires no space before this construction.
+
+  // NonsecureURBGBase::min()
+  static constexpr result_type(min)() { return (URBG::min)(); }
+
+  // NonsecureURBGBase::max()
+  static constexpr result_type(max)() { return (URBG::max)(); }
+
+  // NonsecureURBGBase::operator()()
+  result_type operator()() { return urbg_(); }
+
+  // NonsecureURBGBase::discard()
+  void discard(unsigned long long values) {  // NOLINT(runtime/int)
+    urbg_.discard(values);
+  }
+
+  bool operator==(const NonsecureURBGBase& other) const {
+    return urbg_ == other.urbg_;
+  }
+
+  bool operator!=(const NonsecureURBGBase& other) const {
+    return !(urbg_ == other.urbg_);
+  }
+
+ private:
+  // Seeder is a custom seed sequence type where generate() fills the provided
+  // buffer via the RandenPool entropy source.
+  struct Seeder {
+    using result_type = uint32_t;
+
+    size_t size() { return 0; }
+
+    template <typename OutIterator>
+    void param(OutIterator) const {}
+
+    template <typename RandomAccessIterator>
+    void generate(RandomAccessIterator begin, RandomAccessIterator end) {
+      if (begin != end) {
+        // begin, end must be random access iterators assignable from uint32_t.
+        generate_impl(
+            std::integral_constant<bool, sizeof(*begin) == sizeof(uint32_t)>{},
+            begin, end);
+      }
+    }
+
+    // Commonly, generate is invoked with a pointer to a buffer which
+    // can be cast to a uint32_t.
+    template <typename RandomAccessIterator>
+    void generate_impl(std::integral_constant<bool, true>,
+                       RandomAccessIterator begin, RandomAccessIterator end) {
+      auto buffer = absl::MakeSpan(begin, end);
+      auto target = absl::MakeSpan(reinterpret_cast<uint32_t*>(buffer.data()),
+                                   buffer.size());
+      RandenPool<uint32_t>::Fill(target);
+    }
+
+    // The non-uint32_t case should be uncommon, and involves an extra copy,
+    // filling the uint32_t buffer and then mixing into the output.
+    template <typename RandomAccessIterator>
+    void generate_impl(std::integral_constant<bool, false>,
+                       RandomAccessIterator begin, RandomAccessIterator end) {
+      const size_t n = std::distance(begin, end);
+      absl::InlinedVector<uint32_t, 8> data(n, 0);
+      RandenPool<uint32_t>::Fill(absl::MakeSpan(data.begin(), data.end()));
+      std::copy(std::begin(data), std::end(data), begin);
+    }
+  };
+
+  static URBG ConstructURBG() {
+    Seeder seeder;
+    return URBG(seeder);
+  }
+
+  template <typename SSeq>
+  static URBG ConstructURBG(SSeq&& seq) {  // NOLINT(runtime/references)
+    auto salted_seq =
+        random_internal::MakeSaltedSeedSeq(std::forward<SSeq>(seq));
+    return URBG(salted_seq);
+  }
+
+  URBG urbg_;
+};
+
+}  // namespace random_internal
+}  // namespace absl
+
+#endif  // ABSL_RANDOM_INTERNAL_NONSECURE_BASE_H_