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Diffstat (limited to 'third_party/abseil_cpp/absl/random/internal/fast_uniform_bits_test.cc')
| -rw-r--r-- | third_party/abseil_cpp/absl/random/internal/fast_uniform_bits_test.cc | 336 |
1 files changed, 0 insertions, 336 deletions
diff --git a/third_party/abseil_cpp/absl/random/internal/fast_uniform_bits_test.cc b/third_party/abseil_cpp/absl/random/internal/fast_uniform_bits_test.cc deleted file mode 100644 index cee702df85..0000000000 --- a/third_party/abseil_cpp/absl/random/internal/fast_uniform_bits_test.cc +++ /dev/null @@ -1,336 +0,0 @@ -// 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; - - FakeUrbg() = default; - explicit FakeUrbg(bool r) : reject(r) {} - - static constexpr result_type(max)() { return Hi; } - static constexpr result_type(min)() { return Lo; } - result_type operator()() { - // when reject is set, return Hi half the time. - return ((++calls % 2) == 1 && reject) ? Hi : Val; - } - - bool reject = false; - size_t calls = 0; -}; - -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{4})); - 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{4})); - 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{4})); - 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(0, IntegerLog2(uint16_t{0})); - EXPECT_EQ(0, IntegerLog2(uint16_t{1})); - EXPECT_EQ(1, IntegerLog2(uint16_t{2})); - EXPECT_EQ(1, IntegerLog2(uint16_t{3})); - EXPECT_EQ(2, IntegerLog2(uint16_t{4})); - EXPECT_EQ(2, IntegerLog2(uint16_t{5})); - EXPECT_EQ(2, IntegerLog2(uint16_t{7})); - EXPECT_EQ(3, IntegerLog2(uint16_t{8})); - EXPECT_EQ(63, IntegerLog2((std::numeric_limits<uint64_t>::max)())); -} - -TEST(FastUniformBitsTest, RangeSize) { - EXPECT_EQ(2, (RangeSize<FakeUrbg<uint8_t, 0, 1>>())); - EXPECT_EQ(3, (RangeSize<FakeUrbg<uint8_t, 0, 2>>())); - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint8_t, 0, 3>>())); - // EXPECT_EQ(0, (RangeSize<FakeUrbg<uint8_t, 2, 2>>())); - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint8_t, 2, 5>>())); - EXPECT_EQ(5, (RangeSize<FakeUrbg<uint8_t, 2, 6>>())); - EXPECT_EQ(9, (RangeSize<FakeUrbg<uint8_t, 2, 10>>())); - EXPECT_EQ( - 0, (RangeSize< - FakeUrbg<uint8_t, 0, (std::numeric_limits<uint8_t>::max)()>>())); - - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint16_t, 0, 3>>())); - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint16_t, 2, 5>>())); - EXPECT_EQ(5, (RangeSize<FakeUrbg<uint16_t, 2, 6>>())); - EXPECT_EQ(18, (RangeSize<FakeUrbg<uint16_t, 1000, 1017>>())); - EXPECT_EQ( - 0, (RangeSize< - FakeUrbg<uint16_t, 0, (std::numeric_limits<uint16_t>::max)()>>())); - - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint32_t, 0, 3>>())); - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint32_t, 2, 5>>())); - EXPECT_EQ(5, (RangeSize<FakeUrbg<uint32_t, 2, 6>>())); - EXPECT_EQ(18, (RangeSize<FakeUrbg<uint32_t, 1000, 1017>>())); - EXPECT_EQ(0, (RangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>())); - EXPECT_EQ(0xffffffff, (RangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>())); - EXPECT_EQ(0xfffffffe, (RangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>())); - EXPECT_EQ(0xfffffffd, (RangeSize<FakeUrbg<uint32_t, 2, 0xfffffffe>>())); - EXPECT_EQ( - 0, (RangeSize< - FakeUrbg<uint32_t, 0, (std::numeric_limits<uint32_t>::max)()>>())); - - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint64_t, 0, 3>>())); - EXPECT_EQ(4, (RangeSize<FakeUrbg<uint64_t, 2, 5>>())); - EXPECT_EQ(5, (RangeSize<FakeUrbg<uint64_t, 2, 6>>())); - EXPECT_EQ(18, (RangeSize<FakeUrbg<uint64_t, 1000, 1017>>())); - EXPECT_EQ(0x100000000, (RangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>())); - EXPECT_EQ(0xffffffff, (RangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>())); - EXPECT_EQ(0xfffffffe, (RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>())); - EXPECT_EQ(0xfffffffd, (RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffe>>())); - EXPECT_EQ(0, (RangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffff>>())); - EXPECT_EQ(0xffffffffffffffff, - (RangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffff>>())); - EXPECT_EQ(0xfffffffffffffffe, - (RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffe>>())); - EXPECT_EQ(0xfffffffffffffffd, - (RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffffffffffe>>())); - EXPECT_EQ( - 0, (RangeSize< - FakeUrbg<uint64_t, 0, (std::numeric_limits<uint64_t>::max)()>>())); -} - -// The constants need to be choosen so that an infinite rejection loop doesn't -// happen... -using Urng1_5bit = FakeUrbg<uint8_t, 0, 2, 0>; // ~1.5 bits (range 3) -using Urng4bits = FakeUrbg<uint8_t, 1, 0x10, 2>; -using Urng22bits = FakeUrbg<uint32_t, 0, 0x3fffff, 0x301020>; -using Urng31bits = FakeUrbg<uint32_t, 1, 0xfffffffe, 0x60070f03>; // ~31.9 bits -using Urng32bits = FakeUrbg<uint32_t, 0, 0xffffffff, 0x74010f01>; -using Urng33bits = - FakeUrbg<uint64_t, 1, 0x1ffffffff, 0x013301033>; // ~32.9 bits -using Urng63bits = FakeUrbg<uint64_t, 1, 0xfffffffffffffffe, - 0xfedcba9012345678>; // ~63.9 bits -using Urng64bits = - FakeUrbg<uint64_t, 0, 0xffffffffffffffff, 0x123456780fedcba9>; - -TEST(FastUniformBitsTest, OutputsUpTo32Bits) { - // Tests that how values are composed; the single-bit deltas should be spread - // across each invocation. - Urng1_5bit urng1_5; - Urng4bits urng4; - Urng22bits urng22; - Urng31bits urng31; - Urng32bits urng32; - Urng33bits urng33; - Urng63bits urng63; - Urng64bits urng64; - - // 8-bit types - { - FastUniformBits<uint8_t> fast8; - EXPECT_EQ(0x0, fast8(urng1_5)); - EXPECT_EQ(0x11, fast8(urng4)); - EXPECT_EQ(0x20, fast8(urng22)); - EXPECT_EQ(0x2, fast8(urng31)); - EXPECT_EQ(0x1, fast8(urng32)); - EXPECT_EQ(0x32, fast8(urng33)); - EXPECT_EQ(0x77, fast8(urng63)); - EXPECT_EQ(0xa9, fast8(urng64)); - } - - // 16-bit types - { - FastUniformBits<uint16_t> fast16; - EXPECT_EQ(0x0, fast16(urng1_5)); - EXPECT_EQ(0x1111, fast16(urng4)); - EXPECT_EQ(0x1020, fast16(urng22)); - EXPECT_EQ(0x0f02, fast16(urng31)); - EXPECT_EQ(0x0f01, fast16(urng32)); - EXPECT_EQ(0x1032, fast16(urng33)); - EXPECT_EQ(0x5677, fast16(urng63)); - EXPECT_EQ(0xcba9, fast16(urng64)); - } - - // 32-bit types - { - FastUniformBits<uint32_t> fast32; - EXPECT_EQ(0x0, fast32(urng1_5)); - EXPECT_EQ(0x11111111, fast32(urng4)); - EXPECT_EQ(0x08301020, fast32(urng22)); - EXPECT_EQ(0x0f020f02, fast32(urng31)); - EXPECT_EQ(0x74010f01, fast32(urng32)); - EXPECT_EQ(0x13301032, fast32(urng33)); - EXPECT_EQ(0x12345677, fast32(urng63)); - EXPECT_EQ(0x0fedcba9, fast32(urng64)); - } -} - -TEST(FastUniformBitsTest, Outputs64Bits) { - // Tests that how values are composed; the single-bit deltas should be spread - // across each invocation. - FastUniformBits<uint64_t> fast64; - - { - FakeUrbg<uint8_t, 0, 1, 0> urng0; - FakeUrbg<uint8_t, 0, 1, 1> urng1; - Urng4bits urng4; - Urng22bits urng22; - Urng31bits urng31; - Urng32bits urng32; - Urng33bits urng33; - Urng63bits urng63; - Urng64bits urng64; - - // somewhat degenerate cases only create a single bit. - EXPECT_EQ(0x0, fast64(urng0)); - EXPECT_EQ(64, urng0.calls); - EXPECT_EQ(0xffffffffffffffff, fast64(urng1)); - EXPECT_EQ(64, urng1.calls); - - // less degenerate cases. - EXPECT_EQ(0x1111111111111111, fast64(urng4)); - EXPECT_EQ(16, urng4.calls); - EXPECT_EQ(0x01020c0408301020, fast64(urng22)); - EXPECT_EQ(3, urng22.calls); - EXPECT_EQ(0x387811c3c0870f02, fast64(urng31)); - EXPECT_EQ(3, urng31.calls); - EXPECT_EQ(0x74010f0174010f01, fast64(urng32)); - EXPECT_EQ(2, urng32.calls); - EXPECT_EQ(0x808194040cb01032, fast64(urng33)); - EXPECT_EQ(3, urng33.calls); - EXPECT_EQ(0x1234567712345677, fast64(urng63)); - EXPECT_EQ(2, urng63.calls); - EXPECT_EQ(0x123456780fedcba9, fast64(urng64)); - EXPECT_EQ(1, urng64.calls); - } - - // The 1.5 bit case is somewhat interesting in that the algorithm refinement - // causes one extra small sample. Comments here reference the names used in - // [rand.adapt.ibits] that correspond to this case. - { - Urng1_5bit urng1_5; - - // w = 64 - // R = 3 - // m = 1 - // n' = 64 - // w0' = 1 - // y0' = 2 - // n = (1 <= 0) > 64 : 65 = 65 - // n0 = 65 - (64%65) = 1 - // n1 = 64 - // w0 = 0 - // y0 = 3 - // w1 = 1 - // y1 = 2 - EXPECT_EQ(0x0, fast64(urng1_5)); - EXPECT_EQ(65, urng1_5.calls); - } - - // Validate rejections for non-power-of-2 cases. - { - Urng1_5bit urng1_5(true); - Urng31bits urng31(true); - Urng33bits urng33(true); - Urng63bits urng63(true); - - // For 1.5 bits, there would be 1+2*64, except the first - // value was accepted and shifted off the end. - EXPECT_EQ(0, fast64(urng1_5)); - EXPECT_EQ(128, urng1_5.calls); - EXPECT_EQ(0x387811c3c0870f02, fast64(urng31)); - EXPECT_EQ(6, urng31.calls); - EXPECT_EQ(0x808194040cb01032, fast64(urng33)); - EXPECT_EQ(6, urng33.calls); - EXPECT_EQ(0x1234567712345677, fast64(urng63)); - EXPECT_EQ(4, urng63.calls); - } -} - -TEST(FastUniformBitsTest, URBG32bitRegression) { - // Validate with deterministic 32-bit std::minstd_rand - // to ensure that operator() performs as expected. - - EXPECT_EQ(2147483646, RangeSize<std::minstd_rand>()); - EXPECT_EQ(30, IntegerLog2(RangeSize<std::minstd_rand>())); - - std::minstd_rand gen(1); - FastUniformBits<uint64_t> fast64; - - EXPECT_EQ(0x05e47095f8791f45, fast64(gen)); - EXPECT_EQ(0x028be17e3c07c122, fast64(gen)); - EXPECT_EQ(0x55d2847c1626e8c2, fast64(gen)); -} - -} // namespace -} // namespace random_internal -ABSL_NAMESPACE_END -} // namespace absl |