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, 250 insertions, 0 deletions

diff --git a/absl/random/log_uniform_int_distribution.h b/absl/random/log_uniform_int_distribution.h
new file mode 100644
index 00000000..ac43416e
--- /dev/null
+++ b/absl/random/log_uniform_int_distribution.h
@@ -0,0 +1,250 @@
+// 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_LOG_UNIFORM_INT_DISTRIBUTION_H_
+#define ABSL_RANDOM_LOG_UNIFORM_INT_DISTRIBUTION_H_
+
+#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <istream>
+#include <limits>
+#include <ostream>
+#include <type_traits>
+
+#include "absl/random/internal/distribution_impl.h"
+#include "absl/random/internal/fastmath.h"
+#include "absl/random/internal/iostream_state_saver.h"
+#include "absl/random/internal/traits.h"
+#include "absl/random/uniform_int_distribution.h"
+
+namespace absl {
+
+// log_uniform_int_distribution:
+//
+// Returns a random variate R in range [min, max] such that
+// floor(log(R-min, base)) is uniformly distributed.
+// We ensure uniformity by discretization using the
+// boundary sets [0, 1, base, base * base, ... min(base*n, max)]
+//
+template <typename IntType = int>
+class log_uniform_int_distribution {
+ private:
+  using unsigned_type =
+      typename random_internal::make_unsigned_bits<IntType>::type;
+
+ public:
+  using result_type = IntType;
+
+  class param_type {
+   public:
+    using distribution_type = log_uniform_int_distribution;
+
+    explicit param_type(
+        result_type min = 0,
+        result_type max = (std::numeric_limits<result_type>::max)(),
+        result_type base = 2)
+        : min_(min),
+          max_(max),
+          base_(base),
+          range_(static_cast<unsigned_type>(max_) -
+                 static_cast<unsigned_type>(min_)),
+          log_range_(0) {
+      assert(max_ >= min_);
+      assert(base_ > 1);
+
+      if (base_ == 2) {
+        // Determine where the first set bit is on range(), giving a log2(range)
+        // value which can be used to construct bounds.
+        log_range_ = (std::min)(random_internal::LeadingSetBit(range()),
+                                std::numeric_limits<unsigned_type>::digits);
+      } else {
+        // NOTE: Computing the logN(x) introduces error from 2 sources:
+        // 1. Conversion of int to double loses precision for values >=
+        // 2^53, which may cause some log() computations to operate on
+        // different values.
+        // 2. The error introduced by the division will cause the result
+        // to differ from the expected value.
+        //
+        // Thus a result which should equal K may equal K +/- epsilon,
+        // which can eliminate some values depending on where the bounds fall.
+        const double inv_log_base = 1.0 / std::log(base_);
+        const double log_range = std::log(static_cast<double>(range()) + 0.5);
+        log_range_ = static_cast<int>(std::ceil(inv_log_base * log_range));
+      }
+    }
+
+    result_type(min)() const { return min_; }
+    result_type(max)() const { return max_; }
+    result_type base() const { return base_; }
+
+    friend bool operator==(const param_type& a, const param_type& b) {
+      return a.min_ == b.min_ && a.max_ == b.max_ && a.base_ == b.base_;
+    }
+
+    friend bool operator!=(const param_type& a, const param_type& b) {
+      return !(a == b);
+    }
+
+   private:
+    friend class log_uniform_int_distribution;
+
+    int log_range() const { return log_range_; }
+    unsigned_type range() const { return range_; }
+
+    result_type min_;
+    result_type max_;
+    result_type base_;
+    unsigned_type range_;  // max - min
+    int log_range_;        // ceil(logN(range_))
+
+    static_assert(std::is_integral<IntType>::value,
+                  "Class-template absl::log_uniform_int_distribution<> must be "
+                  "parameterized using an integral type.");
+  };
+
+  log_uniform_int_distribution() : log_uniform_int_distribution(0) {}
+
+  explicit log_uniform_int_distribution(
+      result_type min,
+      result_type max = (std::numeric_limits<result_type>::max)(),
+      result_type base = 2)
+      : param_(min, max, base) {}
+
+  explicit log_uniform_int_distribution(const param_type& p) : param_(p) {}
+
+  void reset() {}
+
+  // generating functions
+  template <typename URBG>
+  result_type operator()(URBG& g) {  // NOLINT(runtime/references)
+    return (*this)(g, param_);
+  }
+
+  template <typename URBG>
+  result_type operator()(URBG& g,  // NOLINT(runtime/references)
+                         const param_type& p) {
+    return (p.min)() + Generate(g, p);
+  }
+
+  result_type(min)() const { return (param_.min)(); }
+  result_type(max)() const { return (param_.max)(); }
+  result_type base() const { return param_.base(); }
+
+  param_type param() const { return param_; }
+  void param(const param_type& p) { param_ = p; }
+
+  friend bool operator==(const log_uniform_int_distribution& a,
+                         const log_uniform_int_distribution& b) {
+    return a.param_ == b.param_;
+  }
+  friend bool operator!=(const log_uniform_int_distribution& a,
+                         const log_uniform_int_distribution& b) {
+    return a.param_ != b.param_;
+  }
+
+ private:
+  // Returns a log-uniform variate in the range [0, p.range()]. The caller
+  // should add min() to shift the result to the correct range.
+  template <typename URNG>
+  unsigned_type Generate(URNG& g,  // NOLINT(runtime/references)
+                         const param_type& p);
+
+  param_type param_;
+};
+
+template <typename IntType>
+template <typename URBG>
+typename log_uniform_int_distribution<IntType>::unsigned_type
+log_uniform_int_distribution<IntType>::Generate(
+    URBG& g,  // NOLINT(runtime/references)
+    const param_type& p) {
+  // sample e over [0, log_range]. Map the results of e to this:
+  // 0 => 0
+  // 1 => [1, b-1]
+  // 2 => [b, (b^2)-1]
+  // n => [b^(n-1)..(b^n)-1]
+  const int e = absl::uniform_int_distribution<int>(0, p.log_range())(g);
+  if (e == 0) {
+    return 0;
+  }
+  const int d = e - 1;
+
+  unsigned_type base_e, top_e;
+  if (p.base() == 2) {
+    base_e = static_cast<unsigned_type>(1) << d;
+
+    top_e = (e >= std::numeric_limits<unsigned_type>::digits)
+                ? (std::numeric_limits<unsigned_type>::max)()
+                : (static_cast<unsigned_type>(1) << e) - 1;
+  } else {
+    const double r = std::pow(p.base(), d);
+    const double s = (r * p.base()) - 1.0;
+
+    base_e = (r > (std::numeric_limits<unsigned_type>::max)())
+                 ? (std::numeric_limits<unsigned_type>::max)()
+                 : static_cast<unsigned_type>(r);
+
+    top_e = (s > (std::numeric_limits<unsigned_type>::max)())
+                ? (std::numeric_limits<unsigned_type>::max)()
+                : static_cast<unsigned_type>(s);
+  }
+
+  const unsigned_type lo = (base_e >= p.range()) ? p.range() : base_e;
+  const unsigned_type hi = (top_e >= p.range()) ? p.range() : top_e;
+
+  // choose uniformly over [lo, hi]
+  return absl::uniform_int_distribution<result_type>(lo, hi)(g);
+}
+
+template <typename CharT, typename Traits, typename IntType>
+std::basic_ostream<CharT, Traits>& operator<<(
+    std::basic_ostream<CharT, Traits>& os,  // NOLINT(runtime/references)
+    const log_uniform_int_distribution<IntType>& x) {
+  using stream_type =
+      typename random_internal::stream_format_type<IntType>::type;
+  auto saver = random_internal::make_ostream_state_saver(os);
+  os << static_cast<stream_type>((x.min)()) << os.fill()
+     << static_cast<stream_type>((x.max)()) << os.fill()
+     << static_cast<stream_type>(x.base());
+  return os;
+}
+
+template <typename CharT, typename Traits, typename IntType>
+std::basic_istream<CharT, Traits>& operator>>(
+    std::basic_istream<CharT, Traits>& is,       // NOLINT(runtime/references)
+    log_uniform_int_distribution<IntType>& x) {  // NOLINT(runtime/references)
+  using param_type = typename log_uniform_int_distribution<IntType>::param_type;
+  using result_type =
+      typename log_uniform_int_distribution<IntType>::result_type;
+  using stream_type =
+      typename random_internal::stream_format_type<IntType>::type;
+
+  stream_type min;
+  stream_type max;
+  stream_type base;
+
+  auto saver = random_internal::make_istream_state_saver(is);
+  is >> min >> max >> base;
+  if (!is.fail()) {
+    x.param(param_type(static_cast<result_type>(min),
+                       static_cast<result_type>(max),
+                       static_cast<result_type>(base)));
+  }
+  return is;
+}
+
+}  // namespace absl
+
+#endif  // ABSL_RANDOM_LOG_UNIFORM_INT_DISTRIBUTION_H_