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snix/absl/numeric/int128_test.cc
Abseil Team ff70456473 Changes imported from Abseil "staging" branch: 
- 20f4e7133d695e9a05e13ebdfd4d78da310b42b5 Remove the warning supressions -Wno-documentation and by Derek Mauro <dmauro@google.com>
  - e1bde85c0571673b1e7a88b9d45a393606ba7e6c Changed the optimized version of strings_internal::JoinAl... by Abseil Team <absl-team@google.com>
  - 746e6716b4c15be61547670d68d25a1c850d3954 Add missing absl:: qualification. by Alex Strelnikov <strel@google.com>
  - 4e5c18c488cbd49ca72b02911cf22d830d5a7f16 Internals change: Remove the ability to pass a custom met... by Greg Falcon <gfalcon@google.com>
  - 65d58107a5730d4b6468bbffc72bea2f980af826 Moved most common character case (ascii printable) out of... by Abseil Team <absl-team@google.com>
  - f031331cc55a3d57b9110e12c7cbe50ac3e2a04f Add missing copyright headers to a few source files. by Greg Falcon <gfalcon@google.com>
  - 6035a77af6fa951c536b42df4c710d16d1817aec Enable libstdc++'s memcmp optimization in absl::equal for... by Abseil Team <absl-team@google.com>
  - 73a665a4a10781e5d89f75a876ece7ad859f4116 Fix minor spelling error "hexidecimal". by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 20f4e7133d695e9a05e13ebdfd4d78da310b42b5
Change-Id: Id8c18ebd331d096935052a6ab259ebe0e2ef13ae
2017-12-20 17:03:18 -05:00

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// 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 <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, TrivialTraitsTest) {
static_assert(absl::is_trivially_default_constructible<absl::uint128>::value,
"");
static_assert(absl::is_trivially_copy_constructible<absl::uint128>::value,
"");
static_assert(absl::is_trivially_copy_assignable<absl::uint128>::value, "");
static_assert(std::is_trivially_destructible<absl::uint128>::value, "");
}
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(absl::Uint128High64(biggest), std::numeric_limits<uint64_t>::max());
EXPECT_EQ(absl::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(absl::Uint128High64((absl::uint128(1) << 64) - 1), 0);
EXPECT_EQ(absl::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));
}
} // namespace
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