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Diffstat (limited to 'absl/numeric/int128_test.cc')
| -rw-r--r-- | absl/numeric/int128_test.cc | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/absl/numeric/int128_test.cc b/absl/numeric/int128_test.cc new file mode 100644 index 000000000000..c8aabeb3184a --- /dev/null +++ b/absl/numeric/int128_test.cc @@ -0,0 +1,492 @@ +// 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 +// +// http://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/numeric/int128.h" + +#include <algorithm> +#include <limits> +#include <random> +#include <sstream> +#include <type_traits> +#include <utility> +#include <vector> + +#include "gtest/gtest.h" +#include "absl/base/internal/cycleclock.h" +#include "absl/meta/type_traits.h" + +#if defined(_MSC_VER) && _MSC_VER == 1900 +// Disable "unary minus operator applied to unsigned type" warnings in Microsoft +// Visual C++ 14 (2015). +#pragma warning(disable:4146) +#endif + +namespace { + +template <typename T> +class Uint128IntegerTraitsTest : public ::testing::Test {}; +typedef ::testing::Types<bool, char, signed char, unsigned char, char16_t, + char32_t, wchar_t, + short, // NOLINT(runtime/int) + unsigned short, // NOLINT(runtime/int) + int, unsigned int, + long, // NOLINT(runtime/int) + unsigned long, // NOLINT(runtime/int) + long long, // NOLINT(runtime/int) + unsigned long long> // NOLINT(runtime/int) + IntegerTypes; + +template <typename T> +class Uint128FloatTraitsTest : public ::testing::Test {}; +typedef ::testing::Types<float, double, long double> FloatingPointTypes; + +TYPED_TEST_CASE(Uint128IntegerTraitsTest, IntegerTypes); + +TYPED_TEST(Uint128IntegerTraitsTest, ConstructAssignTest) { + static_assert(std::is_constructible<absl::uint128, TypeParam>::value, + "absl::uint128 must be constructible from TypeParam"); + static_assert(std::is_assignable<absl::uint128&, TypeParam>::value, + "absl::uint128 must be assignable from TypeParam"); + static_assert(!std::is_assignable<TypeParam&, absl::uint128>::value, + "TypeParam must not be assignable from absl::uint128"); +} + +TYPED_TEST_CASE(Uint128FloatTraitsTest, FloatingPointTypes); + +TYPED_TEST(Uint128FloatTraitsTest, ConstructAssignTest) { + static_assert(std::is_constructible<absl::uint128, TypeParam>::value, + "absl::uint128 must be constructible from TypeParam"); + static_assert(!std::is_assignable<absl::uint128&, TypeParam>::value, + "absl::uint128 must not be assignable from TypeParam"); + static_assert(!std::is_assignable<TypeParam&, absl::uint128>::value, + "TypeParam must not be assignable from absl::uint128"); +} + +#ifdef ABSL_HAVE_INTRINSIC_INT128 +// These type traits done separately as TYPED_TEST requires typeinfo, and not +// all platforms have this for __int128 even though they define the type. +TEST(Uint128, IntrinsicTypeTraitsTest) { + static_assert(std::is_constructible<absl::uint128, __int128>::value, + "absl::uint128 must be constructible from __int128"); + static_assert(std::is_assignable<absl::uint128&, __int128>::value, + "absl::uint128 must be assignable from __int128"); + static_assert(!std::is_assignable<__int128&, absl::uint128>::value, + "__int128 must not be assignable from absl::uint128"); + + static_assert(std::is_constructible<absl::uint128, unsigned __int128>::value, + "absl::uint128 must be constructible from unsigned __int128"); + static_assert(std::is_assignable<absl::uint128&, unsigned __int128>::value, + "absl::uint128 must be assignable from unsigned __int128"); + static_assert(!std::is_assignable<unsigned __int128&, absl::uint128>::value, + "unsigned __int128 must not be assignable from absl::uint128"); +} +#endif // ABSL_HAVE_INTRINSIC_INT128 + +TEST(Uint128, AllTests) { + absl::uint128 zero = 0; + absl::uint128 one = 1; + absl::uint128 one_2arg = absl::MakeUint128(0, 1); + absl::uint128 two = 2; + absl::uint128 three = 3; + absl::uint128 big = absl::MakeUint128(2000, 2); + absl::uint128 big_minus_one = absl::MakeUint128(2000, 1); + absl::uint128 bigger = absl::MakeUint128(2001, 1); + absl::uint128 biggest = absl::kuint128max; + absl::uint128 high_low = absl::MakeUint128(1, 0); + absl::uint128 low_high = + absl::MakeUint128(0, std::numeric_limits<uint64_t>::max()); + EXPECT_LT(one, two); + EXPECT_GT(two, one); + EXPECT_LT(one, big); + EXPECT_LT(one, big); + EXPECT_EQ(one, one_2arg); + EXPECT_NE(one, two); + EXPECT_GT(big, one); + EXPECT_GE(big, two); + EXPECT_GE(big, big_minus_one); + EXPECT_GT(big, big_minus_one); + EXPECT_LT(big_minus_one, big); + EXPECT_LE(big_minus_one, big); + EXPECT_NE(big_minus_one, big); + EXPECT_LT(big, biggest); + EXPECT_LE(big, biggest); + EXPECT_GT(biggest, big); + EXPECT_GE(biggest, big); + EXPECT_EQ(big, ~~big); + EXPECT_EQ(one, one | one); + EXPECT_EQ(big, big | big); + EXPECT_EQ(one, one | zero); + EXPECT_EQ(one, one & one); + EXPECT_EQ(big, big & big); + EXPECT_EQ(zero, one & zero); + EXPECT_EQ(zero, big & ~big); + EXPECT_EQ(zero, one ^ one); + EXPECT_EQ(zero, big ^ big); + EXPECT_EQ(one, one ^ zero); + + // Shift operators. + EXPECT_EQ(big, big << 0); + EXPECT_EQ(big, big >> 0); + EXPECT_GT(big << 1, big); + EXPECT_LT(big >> 1, big); + EXPECT_EQ(big, (big << 10) >> 10); + EXPECT_EQ(big, (big >> 1) << 1); + EXPECT_EQ(one, (one << 80) >> 80); + EXPECT_EQ(zero, (one >> 80) << 80); + + // Shift assignments. + absl::uint128 big_copy = big; + EXPECT_EQ(big << 0, big_copy <<= 0); + big_copy = big; + EXPECT_EQ(big >> 0, big_copy >>= 0); + big_copy = big; + EXPECT_EQ(big << 1, big_copy <<= 1); + big_copy = big; + EXPECT_EQ(big >> 1, big_copy >>= 1); + big_copy = big; + EXPECT_EQ(big << 10, big_copy <<= 10); + big_copy = big; + EXPECT_EQ(big >> 10, big_copy >>= 10); + big_copy = big; + EXPECT_EQ(big << 64, big_copy <<= 64); + big_copy = big; + EXPECT_EQ(big >> 64, big_copy >>= 64); + big_copy = big; + EXPECT_EQ(big << 73, big_copy <<= 73); + big_copy = big; + EXPECT_EQ(big >> 73, big_copy >>= 73); + + EXPECT_EQ(Uint128High64(biggest), std::numeric_limits<uint64_t>::max()); + EXPECT_EQ(Uint128Low64(biggest), std::numeric_limits<uint64_t>::max()); + EXPECT_EQ(zero + one, one); + EXPECT_EQ(one + one, two); + EXPECT_EQ(big_minus_one + one, big); + EXPECT_EQ(one - one, zero); + EXPECT_EQ(one - zero, one); + EXPECT_EQ(zero - one, biggest); + EXPECT_EQ(big - big, zero); + EXPECT_EQ(big - one, big_minus_one); + EXPECT_EQ(big + std::numeric_limits<uint64_t>::max(), bigger); + EXPECT_EQ(biggest + 1, zero); + EXPECT_EQ(zero - 1, biggest); + EXPECT_EQ(high_low - one, low_high); + EXPECT_EQ(low_high + one, high_low); + EXPECT_EQ(Uint128High64((absl::uint128(1) << 64) - 1), 0); + EXPECT_EQ(Uint128Low64((absl::uint128(1) << 64) - 1), + std::numeric_limits<uint64_t>::max()); + EXPECT_TRUE(!!one); + EXPECT_TRUE(!!high_low); + EXPECT_FALSE(!!zero); + EXPECT_FALSE(!one); + EXPECT_FALSE(!high_low); + EXPECT_TRUE(!zero); + EXPECT_TRUE(zero == 0); // NOLINT(readability/check) + EXPECT_FALSE(zero != 0); // NOLINT(readability/check) + EXPECT_FALSE(one == 0); // NOLINT(readability/check) + EXPECT_TRUE(one != 0); // NOLINT(readability/check) + EXPECT_FALSE(high_low == 0); // NOLINT(readability/check) + EXPECT_TRUE(high_low != 0); // NOLINT(readability/check) + + absl::uint128 test = zero; + EXPECT_EQ(++test, one); + EXPECT_EQ(test, one); + EXPECT_EQ(test++, one); + EXPECT_EQ(test, two); + EXPECT_EQ(test -= 2, zero); + EXPECT_EQ(test, zero); + EXPECT_EQ(test += 2, two); + EXPECT_EQ(test, two); + EXPECT_EQ(--test, one); + EXPECT_EQ(test, one); + EXPECT_EQ(test--, one); + EXPECT_EQ(test, zero); + EXPECT_EQ(test |= three, three); + EXPECT_EQ(test &= one, one); + EXPECT_EQ(test ^= three, two); + EXPECT_EQ(test >>= 1, one); + EXPECT_EQ(test <<= 1, two); + + EXPECT_EQ(big, -(-big)); + EXPECT_EQ(two, -((-one) - 1)); + EXPECT_EQ(absl::kuint128max, -one); + EXPECT_EQ(zero, -zero); +} + +TEST(Uint128, ConversionTests) { + EXPECT_TRUE(absl::MakeUint128(1, 0)); + +#ifdef ABSL_HAVE_INTRINSIC_INT128 + unsigned __int128 intrinsic = + (static_cast<unsigned __int128>(0x3a5b76c209de76f6) << 64) + + 0x1f25e1d63a2b46c5; + absl::uint128 custom = + absl::MakeUint128(0x3a5b76c209de76f6, 0x1f25e1d63a2b46c5); + + EXPECT_EQ(custom, absl::uint128(intrinsic)); + EXPECT_EQ(custom, absl::uint128(static_cast<__int128>(intrinsic))); + EXPECT_EQ(intrinsic, static_cast<unsigned __int128>(custom)); + EXPECT_EQ(intrinsic, static_cast<__int128>(custom)); +#endif // ABSL_HAVE_INTRINSIC_INT128 + + // verify that an integer greater than 2**64 that can be stored precisely + // inside a double is converted to a absl::uint128 without loss of + // information. + double precise_double = 0x530e * std::pow(2.0, 64.0) + 0xda74000000000000; + absl::uint128 from_precise_double(precise_double); + absl::uint128 from_precise_ints = + absl::MakeUint128(0x530e, 0xda74000000000000); + EXPECT_EQ(from_precise_double, from_precise_ints); + EXPECT_DOUBLE_EQ(static_cast<double>(from_precise_ints), precise_double); + + double approx_double = 0xffffeeeeddddcccc * std::pow(2.0, 64.0) + + 0xbbbbaaaa99998888; + absl::uint128 from_approx_double(approx_double); + EXPECT_DOUBLE_EQ(static_cast<double>(from_approx_double), approx_double); + + double round_to_zero = 0.7; + double round_to_five = 5.8; + double round_to_nine = 9.3; + EXPECT_EQ(static_cast<absl::uint128>(round_to_zero), 0); + EXPECT_EQ(static_cast<absl::uint128>(round_to_five), 5); + EXPECT_EQ(static_cast<absl::uint128>(round_to_nine), 9); +} + +TEST(Uint128, OperatorAssignReturnRef) { + absl::uint128 v(1); + (v += 4) -= 3; + EXPECT_EQ(2, v); +} + +TEST(Uint128, Multiply) { + absl::uint128 a, b, c; + + // Zero test. + a = 0; + b = 0; + c = a * b; + EXPECT_EQ(0, c); + + // Max carries. + a = absl::uint128(0) - 1; + b = absl::uint128(0) - 1; + c = a * b; + EXPECT_EQ(1, c); + + // Self-operation with max carries. + c = absl::uint128(0) - 1; + c *= c; + EXPECT_EQ(1, c); + + // 1-bit x 1-bit. + for (int i = 0; i < 64; ++i) { + for (int j = 0; j < 64; ++j) { + a = absl::uint128(1) << i; + b = absl::uint128(1) << j; + c = a * b; + EXPECT_EQ(absl::uint128(1) << (i + j), c); + } + } + + // Verified with dc. + a = absl::MakeUint128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888); + b = absl::MakeUint128(0x7777666655554444, 0x3333222211110000); + c = a * b; + EXPECT_EQ(absl::MakeUint128(0x530EDA741C71D4C3, 0xBF25975319080000), c); + EXPECT_EQ(0, c - b * a); + EXPECT_EQ(a*a - b*b, (a+b) * (a-b)); + + // Verified with dc. + a = absl::MakeUint128(0x0123456789abcdef, 0xfedcba9876543210); + b = absl::MakeUint128(0x02468ace13579bdf, 0xfdb97531eca86420); + c = a * b; + EXPECT_EQ(absl::MakeUint128(0x97a87f4f261ba3f2, 0x342d0bbf48948200), c); + EXPECT_EQ(0, c - b * a); + EXPECT_EQ(a*a - b*b, (a+b) * (a-b)); +} + +TEST(Uint128, AliasTests) { + absl::uint128 x1 = absl::MakeUint128(1, 2); + absl::uint128 x2 = absl::MakeUint128(2, 4); + x1 += x1; + EXPECT_EQ(x2, x1); + + absl::uint128 x3 = absl::MakeUint128(1, static_cast<uint64_t>(1) << 63); + absl::uint128 x4 = absl::MakeUint128(3, 0); + x3 += x3; + EXPECT_EQ(x4, x3); +} + +TEST(Uint128, DivideAndMod) { + using std::swap; + + // a := q * b + r + absl::uint128 a, b, q, r; + + // Zero test. + a = 0; + b = 123; + q = a / b; + r = a % b; + EXPECT_EQ(0, q); + EXPECT_EQ(0, r); + + a = absl::MakeUint128(0x530eda741c71d4c3, 0xbf25975319080000); + q = absl::MakeUint128(0x4de2cab081, 0x14c34ab4676e4bab); + b = absl::uint128(0x1110001); + r = absl::uint128(0x3eb455); + ASSERT_EQ(a, q * b + r); // Sanity-check. + + absl::uint128 result_q, result_r; + result_q = a / b; + result_r = a % b; + EXPECT_EQ(q, result_q); + EXPECT_EQ(r, result_r); + + // Try the other way around. + swap(q, b); + result_q = a / b; + result_r = a % b; + EXPECT_EQ(q, result_q); + EXPECT_EQ(r, result_r); + // Restore. + swap(b, q); + + // Dividend < divisor; result should be q:0 r:<dividend>. + swap(a, b); + result_q = a / b; + result_r = a % b; + EXPECT_EQ(0, result_q); + EXPECT_EQ(a, result_r); + // Try the other way around. + swap(a, q); + result_q = a / b; + result_r = a % b; + EXPECT_EQ(0, result_q); + EXPECT_EQ(a, result_r); + // Restore. + swap(q, a); + swap(b, a); + + // Try a large remainder. + b = a / 2 + 1; + absl::uint128 expected_r = + absl::MakeUint128(0x29876d3a0e38ea61, 0xdf92cba98c83ffff); + // Sanity checks. + ASSERT_EQ(a / 2 - 1, expected_r); + ASSERT_EQ(a, b + expected_r); + result_q = a / b; + result_r = a % b; + EXPECT_EQ(1, result_q); + EXPECT_EQ(expected_r, result_r); +} + +TEST(Uint128, DivideAndModRandomInputs) { + const int kNumIters = 1 << 18; + std::minstd_rand random(testing::UnitTest::GetInstance()->random_seed()); + std::uniform_int_distribution<uint64_t> uniform_uint64; + for (int i = 0; i < kNumIters; ++i) { + const absl::uint128 a = + absl::MakeUint128(uniform_uint64(random), uniform_uint64(random)); + const absl::uint128 b = + absl::MakeUint128(uniform_uint64(random), uniform_uint64(random)); + if (b == 0) { + continue; // Avoid a div-by-zero. + } + const absl::uint128 q = a / b; + const absl::uint128 r = a % b; + ASSERT_EQ(a, b * q + r); + } +} + +TEST(Uint128, ConstexprTest) { + constexpr absl::uint128 zero = absl::uint128(); + constexpr absl::uint128 one = 1; + constexpr absl::uint128 minus_two = -2; + EXPECT_EQ(zero, absl::uint128(0)); + EXPECT_EQ(one, absl::uint128(1)); + EXPECT_EQ(minus_two, absl::MakeUint128(-1, -2)); +} + +TEST(Uint128, Traits) { + EXPECT_TRUE(absl::is_trivially_copy_constructible<absl::uint128>::value); + EXPECT_TRUE(absl::is_trivially_copy_assignable<absl::uint128>::value); + EXPECT_TRUE(std::is_trivially_destructible<absl::uint128>::value); +} + +TEST(Uint128, OStream) { + struct { + absl::uint128 val; + std::ios_base::fmtflags flags; + std::streamsize width; + char fill; + const char* rep; + } cases[] = { + // zero with different bases + {absl::uint128(0), std::ios::dec, 0, '_', "0"}, + {absl::uint128(0), std::ios::oct, 0, '_', "0"}, + {absl::uint128(0), std::ios::hex, 0, '_', "0"}, + // crossover between lo_ and hi_ + {absl::MakeUint128(0, -1), std::ios::dec, 0, '_', "18446744073709551615"}, + {absl::MakeUint128(0, -1), std::ios::oct, 0, '_', + "1777777777777777777777"}, + {absl::MakeUint128(0, -1), std::ios::hex, 0, '_', "ffffffffffffffff"}, + {absl::MakeUint128(1, 0), std::ios::dec, 0, '_', "18446744073709551616"}, + {absl::MakeUint128(1, 0), std::ios::oct, 0, '_', + "2000000000000000000000"}, + {absl::MakeUint128(1, 0), std::ios::hex, 0, '_', "10000000000000000"}, + // just the top bit + {absl::MakeUint128(0x8000000000000000, 0), std::ios::dec, 0, '_', + "170141183460469231731687303715884105728"}, + {absl::MakeUint128(0x8000000000000000, 0), std::ios::oct, 0, '_', + "2000000000000000000000000000000000000000000"}, + {absl::MakeUint128(0x8000000000000000, 0), std::ios::hex, 0, '_', + "80000000000000000000000000000000"}, + // maximum absl::uint128 value + {absl::MakeUint128(-1, -1), std::ios::dec, 0, '_', + "340282366920938463463374607431768211455"}, + {absl::MakeUint128(-1, -1), std::ios::oct, 0, '_', + "3777777777777777777777777777777777777777777"}, + {absl::MakeUint128(-1, -1), std::ios::hex, 0, '_', + "ffffffffffffffffffffffffffffffff"}, + // uppercase + {absl::MakeUint128(-1, -1), std::ios::hex | std::ios::uppercase, 0, '_', + "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"}, + // showbase + {absl::uint128(1), std::ios::dec | std::ios::showbase, 0, '_', "1"}, + {absl::uint128(1), std::ios::oct | std::ios::showbase, 0, '_', "01"}, + {absl::uint128(1), std::ios::hex | std::ios::showbase, 0, '_', "0x1"}, + // showbase does nothing on zero + {absl::uint128(0), std::ios::dec | std::ios::showbase, 0, '_', "0"}, + {absl::uint128(0), std::ios::oct | std::ios::showbase, 0, '_', "0"}, + {absl::uint128(0), std::ios::hex | std::ios::showbase, 0, '_', "0"}, + // showpos does nothing on unsigned types + {absl::uint128(1), std::ios::dec | std::ios::showpos, 0, '_', "1"}, + // padding + {absl::uint128(9), std::ios::dec, 6, '_', "_____9"}, + {absl::uint128(12345), std::ios::dec, 6, '_', "_12345"}, + // left adjustment + {absl::uint128(9), std::ios::dec | std::ios::left, 6, '_', "9_____"}, + {absl::uint128(12345), std::ios::dec | std::ios::left, 6, '_', "12345_"}, + }; + for (const auto& test_case : cases) { + std::ostringstream os; + os.flags(test_case.flags); + os.width(test_case.width); + os.fill(test_case.fill); + os << test_case.val; + EXPECT_EQ(test_case.rep, os.str()); + } +} + +} // namespace |