Export of internal Abseil changes.

--
7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 254454546

--
ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254451562

--
deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson <johnsoncj@google.com>:

Account for subtracting unsigned values from the size of InlinedVector

PiperOrigin-RevId: 254450625

--
3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer <asoffer@google.com>:

Add C++17's std::make_from_tuple to absl/utility/utility.h

PiperOrigin-RevId: 254411573

--
4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for the rest of the InlinedVector public API

PiperOrigin-RevId: 254408378

--
e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson <johnsoncj@google.com>:

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 <lar@google.com>:

Use absl::InsecureBitGen in place of std::mt19937
in tests absl/random/...distribution_test.cc

PiperOrigin-RevId: 254289444

--
fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254286334

--
ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254273059

--
6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown <jorg@google.com>:

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 <asoffer@google.com>:

Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for
IntervalOpenOpen.

PiperOrigin-RevId: 254252419

--
ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team <absl-team@google.com>:

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 <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254242321

--
cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for InlinedVector::reserve(size_type)

PiperOrigin-RevId: 254199226

--
c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental <rogeeff@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 254072387

--
c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt <lar@google.com>:

Internal cleanup.

PiperOrigin-RevId: 254062381

--
d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck <shreck@google.com>:

Update distributions.h to Abseil standards

PiperOrigin-RevId: 254054946

--
d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson <johnsoncj@google.com>:

Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions

PiperOrigin-RevId: 254005427

--
2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253999861

--
24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson <johnsoncj@google.com>:

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 <johnsoncj@google.com>:

Adds benchmarks for InlinedVector::shrink_to_fit()

PiperOrigin-RevId: 253989647

--
2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team <absl-team@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253927497

--
bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253920512

--
bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 253886486

--
05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier <ericwf@google.com>:

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

1 files changed, 129 insertions, 0 deletions

diff --git a/absl/random/internal/pool_urbg.h b/absl/random/internal/pool_urbg.h
new file mode 100644
index 000000000000..9b2dd4bfceeb
--- /dev/null
+++ b/absl/random/internal/pool_urbg.h
@@ -0,0 +1,129 @@
+// 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_POOL_URBG_H_
+#define ABSL_RANDOM_INTERNAL_POOL_URBG_H_
+
+#include <cinttypes>
+#include <limits>
+
+#include "absl/random/internal/traits.h"
+#include "absl/types/span.h"
+
+namespace absl {
+namespace random_internal {
+
+// RandenPool is a thread-safe random number generator [random.req.urbg] that
+// uses an underlying pool of Randen generators to generate values.  Each thread
+// has affinity to one instance of the underlying pool generators.  Concurrent
+// access is guarded by a spin-lock.
+template <typename T>
+class RandenPool {
+ public:
+  using result_type = T;
+  static_assert(std::is_unsigned<result_type>::value,
+                "RandenPool template argument must be a built-in unsigned "
+                "integer type");
+
+  static constexpr result_type(min)() {
+    return (std::numeric_limits<result_type>::min)();
+  }
+
+  static constexpr result_type(max)() {
+    return (std::numeric_limits<result_type>::max)();
+  }
+
+  RandenPool() {}
+
+  // Returns a single value.
+  inline result_type operator()() { return Generate(); }
+
+  // Fill data with random values.
+  static void Fill(absl::Span<result_type> data);
+
+ protected:
+  // Generate returns a single value.
+  static result_type Generate();
+};
+
+extern template class RandenPool<uint8_t>;
+extern template class RandenPool<uint16_t>;
+extern template class RandenPool<uint32_t>;
+extern template class RandenPool<uint64_t>;
+
+// PoolURBG uses an underlying pool of random generators to implement a
+// thread-compatible [random.req.urbg] interface with an internal cache of
+// values.
+template <typename T, size_t kBufferSize>
+class PoolURBG {
+  // Inheritance to access the protected static members of RandenPool.
+  using unsigned_type = typename make_unsigned_bits<T>::type;
+  using PoolType = RandenPool<unsigned_type>;
+  using SpanType = absl::Span<unsigned_type>;
+
+  static constexpr size_t kInitialBuffer = kBufferSize + 1;
+  static constexpr size_t kHalfBuffer = kBufferSize / 2;
+
+ public:
+  using result_type = T;
+
+  static_assert(std::is_unsigned<result_type>::value,
+                "PoolURBG must be parameterized by an unsigned integer type");
+
+  static_assert(kBufferSize > 1,
+                "PoolURBG must be parameterized by a buffer-size > 1");
+
+  static_assert(kBufferSize <= 256,
+                "PoolURBG must be parameterized by a buffer-size <= 256");
+
+  static constexpr result_type(min)() {
+    return (std::numeric_limits<result_type>::min)();
+  }
+
+  static constexpr result_type(max)() {
+    return (std::numeric_limits<result_type>::max)();
+  }
+
+  PoolURBG() : next_(kInitialBuffer) {}
+
+  // copy-constructor does not copy cache.
+  PoolURBG(const PoolURBG&) : next_(kInitialBuffer) {}
+  const PoolURBG& operator=(const PoolURBG&) {
+    next_ = kInitialBuffer;
+    return *this;
+  }
+
+  // move-constructor does move cache.
+  PoolURBG(PoolURBG&&) = default;
+  PoolURBG& operator=(PoolURBG&&) = default;
+
+  inline result_type operator()() {
+    if (next_ >= kBufferSize) {
+      next_ = (kBufferSize > 2 && next_ > kBufferSize) ? kHalfBuffer : 0;
+      PoolType::Fill(SpanType(reinterpret_cast<unsigned_type*>(state_ + next_),
+                              kBufferSize - next_));
+    }
+    return state_[next_++];
+  }
+
+ private:
+  // Buffer size.
+  size_t next_;  // index within state_
+  result_type state_[kBufferSize];
+};
+
+}  // namespace random_internal
+}  // namespace absl
+
+#endif  // ABSL_RANDOM_INTERNAL_POOL_URBG_H_