diff options
Diffstat (limited to 'absl/random/internal/fast_uniform_bits_test.cc')
| -rw-r--r-- | absl/random/internal/fast_uniform_bits_test.cc | 241 |
1 files changed, 189 insertions, 52 deletions
diff --git a/absl/random/internal/fast_uniform_bits_test.cc b/absl/random/internal/fast_uniform_bits_test.cc index 18377944..9f2e8268 100644 --- a/absl/random/internal/fast_uniform_bits_test.cc +++ b/absl/random/internal/fast_uniform_bits_test.cc @@ -18,6 +18,8 @@ #include "gtest/gtest.h" +namespace absl { +namespace random_internal { namespace { template <typename IntType> @@ -29,7 +31,7 @@ TYPED_TEST_SUITE(FastUniformBitsTypedTest, IntTypes); TYPED_TEST(FastUniformBitsTypedTest, BasicTest) { using Limits = std::numeric_limits<TypeParam>; - using FastBits = absl::random_internal::FastUniformBits<TypeParam>; + using FastBits = FastUniformBits<TypeParam>; EXPECT_EQ(0, FastBits::min()); EXPECT_EQ(Limits::max(), FastBits::max()); @@ -45,91 +47,226 @@ TYPED_TEST(FastUniformBitsTypedTest, BasicTest) { } } -class UrngOddbits { - public: - using result_type = uint8_t; - static constexpr result_type min() { return 1; } - static constexpr result_type max() { return 0xfe; } - result_type operator()() { return 2; } -}; +template <typename UIntType, UIntType Lo, UIntType Hi, UIntType Val = Lo> +struct FakeUrbg { + using result_type = UIntType; -class Urng4bits { - public: - using result_type = uint8_t; - static constexpr result_type min() { return 1; } - static constexpr result_type max() { return 0xf + 1; } - result_type operator()() { return 2; } + static constexpr result_type(max)() { return Hi; } + static constexpr result_type(min)() { return Lo; } + result_type operator()() { return Val; } }; -class Urng32bits { - public: - using result_type = uint32_t; - static constexpr result_type min() { return 0; } - static constexpr result_type max() { return 0xffffffff; } - result_type operator()() { return 1; } -}; +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>; -// Compile-time test to validate the helper classes used by FastUniformBits -TEST(FastUniformBitsTest, FastUniformBitsDetails) { - using absl::random_internal::FastUniformBitsLoopingConstants; - using absl::random_internal::FastUniformBitsURBGConstants; +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)())); - // 4-bit URBG - { - using constants = FastUniformBitsURBGConstants<Urng4bits>; - static_assert(constants::kPowerOfTwo == true, - "constants::kPowerOfTwo == false"); - static_assert(constants::kRange == 16, "constants::kRange == false"); - static_assert(constants::kRangeBits == 4, "constants::kRangeBits == false"); - static_assert(constants::kRangeMask == 0x0f, - "constants::kRangeMask == false"); - } + 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)())); - // ~7-bit URBG - { - using constants = FastUniformBitsURBGConstants<UrngOddbits>; - static_assert(constants::kPowerOfTwo == false, - "constants::kPowerOfTwo == false"); - static_assert(constants::kRange == 0xfe, "constants::kRange == 0xfe"); - static_assert(constants::kRangeBits == 7, "constants::kRangeBits == 7"); - static_assert(constants::kRangeMask == 0x7f, - "constants::kRangeMask == 0x7f"); - } + 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 { - absl::random_internal::FastUniformBits<uint8_t> fast8; + FastUniformBits<uint8_t> fast8; EXPECT_EQ(0x11, fast8(urng4)); + EXPECT_EQ(0x2, fast8(urng31)); EXPECT_EQ(0x1, fast8(urng32)); } // 16-bit types { - absl::random_internal::FastUniformBits<uint16_t> fast16; + FastUniformBits<uint16_t> fast16; EXPECT_EQ(0x1111, fast16(urng4)); - EXPECT_EQ(0x1, fast16(urng32)); + EXPECT_EQ(0xf02, fast16(urng31)); + EXPECT_EQ(0xf01, fast16(urng32)); } // 32-bit types { - absl::random_internal::FastUniformBits<uint32_t> fast32; + FastUniformBits<uint32_t> fast32; EXPECT_EQ(0x11111111, fast32(urng4)); - EXPECT_EQ(0x1, fast32(urng32)); + EXPECT_EQ(0x0f020f02, fast32(urng31)); + EXPECT_EQ(0x74010f01, fast32(urng32)); } // 64-bit types { - absl::random_internal::FastUniformBits<uint64_t> fast64; + FastUniformBits<uint64_t> fast64; EXPECT_EQ(0x1111111111111111, fast64(urng4)); - EXPECT_EQ(0x0000000100000001, fast64(urng32)); + 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 +} // namespace absl |