Abseil Common Libraries (C++) (grcp 依赖)
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272 lines
11 KiB
272 lines
11 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#include "absl/random/internal/fast_uniform_bits.h" |
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#include <random> |
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#include "gtest/gtest.h" |
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namespace absl { |
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namespace random_internal { |
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namespace { |
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template <typename IntType> |
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class FastUniformBitsTypedTest : public ::testing::Test {}; |
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using IntTypes = ::testing::Types<uint8_t, uint16_t, uint32_t, uint64_t>; |
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TYPED_TEST_SUITE(FastUniformBitsTypedTest, IntTypes); |
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TYPED_TEST(FastUniformBitsTypedTest, BasicTest) { |
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using Limits = std::numeric_limits<TypeParam>; |
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using FastBits = FastUniformBits<TypeParam>; |
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EXPECT_EQ(0, FastBits::min()); |
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EXPECT_EQ(Limits::max(), FastBits::max()); |
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constexpr int kIters = 10000; |
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std::random_device rd; |
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std::mt19937 gen(rd()); |
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FastBits fast; |
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for (int i = 0; i < kIters; i++) { |
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const auto v = fast(gen); |
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EXPECT_LE(v, FastBits::max()); |
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EXPECT_GE(v, FastBits::min()); |
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} |
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} |
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template <typename UIntType, UIntType Lo, UIntType Hi, UIntType Val = Lo> |
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struct FakeUrbg { |
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using result_type = UIntType; |
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static constexpr result_type(max)() { return Hi; } |
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static constexpr result_type(min)() { return Lo; } |
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result_type operator()() { return Val; } |
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}; |
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using UrngOddbits = FakeUrbg<uint8_t, 1, 0xfe, 0x73>; |
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using Urng4bits = FakeUrbg<uint8_t, 1, 0x10, 2>; |
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using Urng31bits = FakeUrbg<uint32_t, 1, 0xfffffffe, 0x60070f03>; |
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using Urng32bits = FakeUrbg<uint32_t, 0, 0xffffffff, 0x74010f01>; |
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TEST(FastUniformBitsTest, IsPowerOfTwoOrZero) { |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{0})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{1})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{2})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{3})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{16})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{17})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint8_t>::max)())); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{0})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{1})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{2})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{3})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{16})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{17})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint16_t>::max)())); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{0})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{1})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{2})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{3})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{32})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{17})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint32_t>::max)())); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{0})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{1})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{2})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{3})); |
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EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{64})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{17})); |
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EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint64_t>::max)())); |
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} |
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TEST(FastUniformBitsTest, IntegerLog2) { |
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EXPECT_EQ(IntegerLog2(uint16_t{0}), 0); |
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EXPECT_EQ(IntegerLog2(uint16_t{1}), 0); |
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EXPECT_EQ(IntegerLog2(uint16_t{2}), 1); |
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EXPECT_EQ(IntegerLog2(uint16_t{3}), 1); |
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EXPECT_EQ(IntegerLog2(uint16_t{4}), 2); |
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EXPECT_EQ(IntegerLog2(uint16_t{5}), 2); |
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EXPECT_EQ(IntegerLog2(std::numeric_limits<uint64_t>::max()), 63); |
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} |
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TEST(FastUniformBitsTest, RangeSize) { |
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EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 6>>()), 5); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 10>>()), 9); |
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EXPECT_EQ( |
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(RangeSize<FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()), |
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0); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 6>>()), 5); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 18); |
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EXPECT_EQ((RangeSize< |
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FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()), |
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0); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 6>>()), 5); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 18); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()), 0xffffffff); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()), 0xfffffffe); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 0xfffffffe>>()), 0xfffffffd); |
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EXPECT_EQ((RangeSize< |
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FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()), |
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0); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 6>>()), 5); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 18); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()), 0x100000000ull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()), 0xffffffffull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()), 0xfffffffeull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffe>>()), 0xfffffffdull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()), 0ull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()), |
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0xffffffffffffffffull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()), |
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0xfffffffffffffffeull); |
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EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffffffffffeull>>()), |
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0xfffffffffffffffdull); |
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EXPECT_EQ((RangeSize< |
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FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()), |
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0); |
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} |
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TEST(FastUniformBitsTest, PowerOfTwoSubRangeSize) { |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 6>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 10>>()), 8); |
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EXPECT_EQ((PowerOfTwoSubRangeSize< |
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FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()), |
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0); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 6>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 16); |
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EXPECT_EQ((PowerOfTwoSubRangeSize< |
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FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()), |
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0); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 6>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 16); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()), |
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0x80000000); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()), |
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0x80000000); |
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EXPECT_EQ((PowerOfTwoSubRangeSize< |
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FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()), |
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0); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 6>>()), 4); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 16); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()), |
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0x100000000ull); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()), |
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0x80000000ull); |
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EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()), |
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0x80000000ull); |
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EXPECT_EQ( |
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(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()), |
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0); |
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EXPECT_EQ( |
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(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()), |
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0x8000000000000000ull); |
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EXPECT_EQ( |
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(PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()), |
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0x8000000000000000ull); |
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EXPECT_EQ((PowerOfTwoSubRangeSize< |
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FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()), |
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0); |
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} |
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TEST(FastUniformBitsTest, Urng4_VariousOutputs) { |
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// Tests that how values are composed; the single-bit deltas should be spread |
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// across each invocation. |
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Urng4bits urng4; |
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Urng31bits urng31; |
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Urng32bits urng32; |
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// 8-bit types |
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{ |
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FastUniformBits<uint8_t> fast8; |
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EXPECT_EQ(0x11, fast8(urng4)); |
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EXPECT_EQ(0x2, fast8(urng31)); |
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EXPECT_EQ(0x1, fast8(urng32)); |
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} |
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// 16-bit types |
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{ |
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FastUniformBits<uint16_t> fast16; |
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EXPECT_EQ(0x1111, fast16(urng4)); |
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EXPECT_EQ(0xf02, fast16(urng31)); |
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EXPECT_EQ(0xf01, fast16(urng32)); |
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} |
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// 32-bit types |
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{ |
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FastUniformBits<uint32_t> fast32; |
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EXPECT_EQ(0x11111111, fast32(urng4)); |
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EXPECT_EQ(0x0f020f02, fast32(urng31)); |
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EXPECT_EQ(0x74010f01, fast32(urng32)); |
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} |
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// 64-bit types |
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{ |
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FastUniformBits<uint64_t> fast64; |
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EXPECT_EQ(0x1111111111111111, fast64(urng4)); |
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EXPECT_EQ(0x387811c3c0870f02, fast64(urng31)); |
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EXPECT_EQ(0x74010f0174010f01, fast64(urng32)); |
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} |
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} |
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TEST(FastUniformBitsTest, URBG32bitRegression) { |
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// Validate with deterministic 32-bit std::minstd_rand |
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// to ensure that operator() performs as expected. |
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std::minstd_rand gen(1); |
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FastUniformBits<uint64_t> fast64; |
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EXPECT_EQ(0x05e47095f847c122ull, fast64(gen)); |
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EXPECT_EQ(0x8f82c1ba30b64d22ull, fast64(gen)); |
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EXPECT_EQ(0x3b971a3558155039ull, fast64(gen)); |
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} |
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} // namespace |
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} // namespace random_internal |
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} // namespace absl
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