tvl-depot/absl/random/internal/fast_uniform_bits_test.cc
Abseil Team 12bc53e031 Export of internal Abseil changes
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c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>:

Remove a floating point division by zero test.

This isn't testing behavior related to the library, and MSVC warns
about it in opt mode.

PiperOrigin-RevId: 285220804

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68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>:

This CL introduces following changes to the class FlagImpl:
* We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately.
* CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now.
* Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call.
* We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced.

PiperOrigin-RevId: 285132636

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ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>:

Change null-term* (and nul-term*) to NUL-term* in comments

PiperOrigin-RevId: 285036610

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729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>:

Use the Posix implementation of thread identity on MinGW.
Some versions of MinGW suffer from thread_local bugs.

PiperOrigin-RevId: 285022920

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39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>:

Implementation detail change.

Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil.

PiperOrigin-RevId: 285012012
GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c
Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
2019-12-12 15:37:13 -05:00

274 lines
11 KiB
C++

// 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.
#include "absl/random/internal/fast_uniform_bits.h"
#include <random>
#include "gtest/gtest.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace random_internal {
namespace {
template <typename IntType>
class FastUniformBitsTypedTest : public ::testing::Test {};
using IntTypes = ::testing::Types<uint8_t, uint16_t, uint32_t, uint64_t>;
TYPED_TEST_SUITE(FastUniformBitsTypedTest, IntTypes);
TYPED_TEST(FastUniformBitsTypedTest, BasicTest) {
using Limits = std::numeric_limits<TypeParam>;
using FastBits = FastUniformBits<TypeParam>;
EXPECT_EQ(0, FastBits::min());
EXPECT_EQ(Limits::max(), FastBits::max());
constexpr int kIters = 10000;
std::random_device rd;
std::mt19937 gen(rd());
FastBits fast;
for (int i = 0; i < kIters; i++) {
const auto v = fast(gen);
EXPECT_LE(v, FastBits::max());
EXPECT_GE(v, FastBits::min());
}
}
template <typename UIntType, UIntType Lo, UIntType Hi, UIntType Val = Lo>
struct FakeUrbg {
using result_type = UIntType;
static constexpr result_type(max)() { return Hi; }
static constexpr result_type(min)() { return Lo; }
result_type operator()() { return Val; }
};
using UrngOddbits = FakeUrbg<uint8_t, 1, 0xfe, 0x73>;
using Urng4bits = FakeUrbg<uint8_t, 1, 0x10, 2>;
using Urng31bits = FakeUrbg<uint32_t, 1, 0xfffffffe, 0x60070f03>;
using Urng32bits = FakeUrbg<uint32_t, 0, 0xffffffff, 0x74010f01>;
TEST(FastUniformBitsTest, IsPowerOfTwoOrZero) {
EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{0}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{1}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{2}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{3}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{16}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{17}));
EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint8_t>::max)()));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{0}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{1}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{2}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{3}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{16}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{17}));
EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint16_t>::max)()));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{0}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{1}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{2}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{3}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{32}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{17}));
EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint32_t>::max)()));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{0}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{1}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{2}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{3}));
EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{64}));
EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{17}));
EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint64_t>::max)()));
}
TEST(FastUniformBitsTest, IntegerLog2) {
EXPECT_EQ(IntegerLog2(uint16_t{0}), 0);
EXPECT_EQ(IntegerLog2(uint16_t{1}), 0);
EXPECT_EQ(IntegerLog2(uint16_t{2}), 1);
EXPECT_EQ(IntegerLog2(uint16_t{3}), 1);
EXPECT_EQ(IntegerLog2(uint16_t{4}), 2);
EXPECT_EQ(IntegerLog2(uint16_t{5}), 2);
EXPECT_EQ(IntegerLog2(std::numeric_limits<uint64_t>::max()), 63);
}
TEST(FastUniformBitsTest, RangeSize) {
EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1);
EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 6>>()), 5);
EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 10>>()), 9);
EXPECT_EQ(
(RangeSize<FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()),
0);
EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1);
EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 6>>()), 5);
EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 18);
EXPECT_EQ((RangeSize<
FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()),
0);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 6>>()), 5);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 18);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()), 0xffffffff);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()), 0xfffffffe);
EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 0xfffffffe>>()), 0xfffffffd);
EXPECT_EQ((RangeSize<
FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()),
0);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 6>>()), 5);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 18);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()), 0x100000000ull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()), 0xffffffffull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()), 0xfffffffeull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffe>>()), 0xfffffffdull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()), 0ull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()),
0xffffffffffffffffull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()),
0xfffffffffffffffeull);
EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffffffffffeull>>()),
0xfffffffffffffffdull);
EXPECT_EQ((RangeSize<
FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()),
0);
}
TEST(FastUniformBitsTest, PowerOfTwoSubRangeSize) {
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 6>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 10>>()), 8);
EXPECT_EQ((PowerOfTwoSubRangeSize<
FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()),
0);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 6>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 16);
EXPECT_EQ((PowerOfTwoSubRangeSize<
FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()),
0);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 6>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 16);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()),
0x80000000);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()),
0x80000000);
EXPECT_EQ((PowerOfTwoSubRangeSize<
FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()),
0);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 6>>()), 4);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 16);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()),
0x100000000ull);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()),
0x80000000ull);
EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()),
0x80000000ull);
EXPECT_EQ(
(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()),
0);
EXPECT_EQ(
(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()),
0x8000000000000000ull);
EXPECT_EQ(
(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()),
0x8000000000000000ull);
EXPECT_EQ((PowerOfTwoSubRangeSize<
FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()),
0);
}
TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// Tests that how values are composed; the single-bit deltas should be spread
// across each invocation.
Urng4bits urng4;
Urng31bits urng31;
Urng32bits urng32;
// 8-bit types
{
FastUniformBits<uint8_t> fast8;
EXPECT_EQ(0x11, fast8(urng4));
EXPECT_EQ(0x2, fast8(urng31));
EXPECT_EQ(0x1, fast8(urng32));
}
// 16-bit types
{
FastUniformBits<uint16_t> fast16;
EXPECT_EQ(0x1111, fast16(urng4));
EXPECT_EQ(0xf02, fast16(urng31));
EXPECT_EQ(0xf01, fast16(urng32));
}
// 32-bit types
{
FastUniformBits<uint32_t> fast32;
EXPECT_EQ(0x11111111, fast32(urng4));
EXPECT_EQ(0x0f020f02, fast32(urng31));
EXPECT_EQ(0x74010f01, fast32(urng32));
}
// 64-bit types
{
FastUniformBits<uint64_t> fast64;
EXPECT_EQ(0x1111111111111111, fast64(urng4));
EXPECT_EQ(0x387811c3c0870f02, fast64(urng31));
EXPECT_EQ(0x74010f0174010f01, fast64(urng32));
}
}
TEST(FastUniformBitsTest, URBG32bitRegression) {
// Validate with deterministic 32-bit std::minstd_rand
// to ensure that operator() performs as expected.
std::minstd_rand gen(1);
FastUniformBits<uint64_t> fast64;
EXPECT_EQ(0x05e47095f847c122ull, fast64(gen));
EXPECT_EQ(0x8f82c1ba30b64d22ull, fast64(gen));
EXPECT_EQ(0x3b971a3558155039ull, fast64(gen));
}
} // namespace
} // namespace random_internal
ABSL_NAMESPACE_END
} // namespace absl