// Copyright 2018 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/hash/hash.h"
#include <array>
#include <bitset>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <random>
#include <set>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/container/flat_hash_set.h"
#include "absl/hash/hash_testing.h"
#include "absl/hash/internal/spy_hash_state.h"
#include "absl/meta/type_traits.h"
#include "absl/numeric/int128.h"
#include "absl/strings/cord_test_helpers.h"
namespace {
using absl::Hash;
using absl::hash_internal::SpyHashState;
template <typename T>
class HashValueIntTest : public testing::Test {
};
TYPED_TEST_SUITE_P(HashValueIntTest);
template <typename T>
SpyHashState SpyHash(const T& value) {
return SpyHashState::combine(SpyHashState(), value);
}
// Helper trait to verify if T is hashable. We use absl::Hash's poison status to
// detect it.
template <typename T>
using is_hashable = std::is_default_constructible<absl::Hash<T>>;
TYPED_TEST_P(HashValueIntTest, BasicUsage) {
EXPECT_TRUE((is_hashable<TypeParam>::value));
TypeParam n = 42;
EXPECT_EQ(SpyHash(n), SpyHash(TypeParam{42}));
EXPECT_NE(SpyHash(n), SpyHash(TypeParam{0}));
EXPECT_NE(SpyHash(std::numeric_limits<TypeParam>::max()),
SpyHash(std::numeric_limits<TypeParam>::min()));
}
TYPED_TEST_P(HashValueIntTest, FastPath) {
// Test the fast-path to make sure the values are the same.
TypeParam n = 42;
EXPECT_EQ(absl::Hash<TypeParam>{}(n),
absl::Hash<std::tuple<TypeParam>>{}(std::tuple<TypeParam>(n)));
}
REGISTER_TYPED_TEST_CASE_P(HashValueIntTest, BasicUsage, FastPath);
using IntTypes = testing::Types<unsigned char, char, int, int32_t, int64_t, uint32_t,
uint64_t, size_t>;
INSTANTIATE_TYPED_TEST_CASE_P(My, HashValueIntTest, IntTypes);
enum LegacyEnum { kValue1, kValue2, kValue3 };
enum class EnumClass { kValue4, kValue5, kValue6 };
TEST(HashValueTest, EnumAndBool) {
EXPECT_TRUE((is_hashable<LegacyEnum>::value));
EXPECT_TRUE((is_hashable<EnumClass>::value));
EXPECT_TRUE((is_hashable<bool>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
LegacyEnum::kValue1, LegacyEnum::kValue2, LegacyEnum::kValue3)));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
EnumClass::kValue4, EnumClass::kValue5, EnumClass::kValue6)));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(true, false)));
}
TEST(HashValueTest, FloatingPoint) {
EXPECT_TRUE((is_hashable<float>::value));
EXPECT_TRUE((is_hashable<double>::value));
EXPECT_TRUE((is_hashable<long double>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(42.f, 0.f, -0.f, std::numeric_limits<float>::infinity(),
-std::numeric_limits<float>::infinity())));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(42., 0., -0., std::numeric_limits<double>::infinity(),
-std::numeric_limits<double>::infinity())));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
// Add some values with small exponent to test that NORMAL values also
// append their category.
.5L, 1.L, 2.L, 4.L, 42.L, 0.L, -0.L,
17 * static_cast<long double>(std::numeric_limits<double>::max()),
std::numeric_limits<long double>::infinity(),
-std::numeric_limits<long double>::infinity())));
}
TEST(HashValueTest, Pointer) {
EXPECT_TRUE((is_hashable<int*>::value));
int i;
int* ptr = &i;
int* n = nullptr;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(&i, ptr, nullptr, ptr + 1, n)));
}
TEST(HashValueTest, PointerAlignment) {
// We want to make sure that pointer alignment will not cause bits to be
// stuck.
constexpr size_t kTotalSize = 1 << 20;
std::unique_ptr<char[]> data(new char[kTotalSize]);
constexpr size_t kLog2NumValues = 5;
constexpr size_t kNumValues = 1 << kLog2NumValues;
for (size_t align = 1; align < kTotalSize / kNumValues;
align < 8 ? align += 1 : align < 1024 ? align += 8 : align += 32) {
SCOPED_TRACE(align);
ASSERT_LE(align * kNumValues, kTotalSize);
size_t bits_or = 0;
size_t bits_and = ~size_t{};
for (size_t i = 0; i < kNumValues; ++i) {
size_t hash = absl::Hash<void*>()(data.get() + i * align);
bits_or |= hash;
bits_and &= hash;
}
// Limit the scope to the bits we would be using for Swisstable.
constexpr size_t kMask = (1 << (kLog2NumValues + 7)) - 1;
size_t stuck_bits = (~bits_or | bits_and) & kMask;
EXPECT_EQ(stuck_bits, 0) << "0x" << std::hex << stuck_bits;
}
}
TEST(HashValueTest, PairAndTuple) {
EXPECT_TRUE((is_hashable<std::pair<int, int>>::value));
EXPECT_TRUE((is_hashable<std::pair<const int&, const int&>>::value));
EXPECT_TRUE((is_hashable<std::tuple<int&, int&>>::value));
EXPECT_TRUE((is_hashable<std::tuple<int&&, int&&>>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::make_pair(0, 42), std::make_pair(0, 42), std::make_pair(42, 0),
std::make_pair(0, 0), std::make_pair(42, 42), std::make_pair(1, 42))));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(std::make_tuple(0, 0, 0), std::make_tuple(0, 0, 42),
std::make_tuple(0, 23, 0), std::make_tuple(17, 0, 0),
std::make_tuple(42, 0, 0), std::make_tuple(3, 9, 9),
std::make_tuple(0, 0, -42))));
// Test that tuples of lvalue references work (so we need a few lvalues):
int a = 0, b = 1, c = 17, d = 23;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::tie(a, a), std::tie(a, b), std::tie(b, c), std::tie(c, d))));
// Test that tuples of rvalue references work:
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::forward_as_tuple(0, 0, 0), std::forward_as_tuple(0, 0, 42),
std::forward_as_tuple(0, 23, 0), std::forward_as_tuple(17, 0, 0),
std::forward_as_tuple(42, 0, 0), std::forward_as_tuple(3, 9, 9),
std::forward_as_tuple(0, 0, -42))));
}
TEST(HashValueTest, CombineContiguousWorks) {
std::vector<std::tuple<int>> v1 = {std::make_tuple(1), std::make_tuple(3)};
std::vector<std::tuple<int>> v2 = {std::make_tuple(1), std::make_tuple(2)};
auto vh1 = SpyHash(v1);
auto vh2 = SpyHash(v2);
EXPECT_NE(vh1, vh2);
}
struct DummyDeleter {
template <typename T>
void operator() (T* ptr) {}
};
struct SmartPointerEq {
template <typename T, typename U>
bool operator()(const T& t, const U& u) const {
return GetPtr(t) == GetPtr(u);
}
template <typename T>
static auto GetPtr(const T& t) -> decltype(&*t) {
return t ? &*t : nullptr;
}
static std::nullptr_t GetPtr(std::nullptr_t) { return nullptr; }
};
TEST(HashValueTest, SmartPointers) {
EXPECT_TRUE((is_hashable<std::unique_ptr<int>>::value));
EXPECT_TRUE((is_hashable<std::unique_ptr<int, DummyDeleter>>::value));
EXPECT_TRUE((is_hashable<std::shared_ptr<int>>::value));
int i, j;
std::unique_ptr<int, DummyDeleter> unique1(&i);
std::unique_ptr<int, DummyDeleter> unique2(&i);
std::unique_ptr<int, DummyDeleter> unique_other(&j);
std::unique_ptr<int, DummyDeleter> unique_null;
std::shared_ptr<int> shared1(&i, DummyDeleter());
std::shared_ptr<int> shared2(&i, DummyDeleter());
std::shared_ptr<int> shared_other(&j, DummyDeleter());
std::shared_ptr<int> shared_null;
// Sanity check of the Eq function.
ASSERT_TRUE(SmartPointerEq{}(unique1, shared1));
ASSERT_FALSE(SmartPointerEq{}(unique1, shared_other));
ASSERT_TRUE(SmartPointerEq{}(unique_null, nullptr));
ASSERT_FALSE(SmartPointerEq{}(shared2, nullptr));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::forward_as_tuple(&i, nullptr, //
unique1, unique2, unique_null, //
absl::make_unique<int>(), //
shared1, shared2, shared_null, //
std::make_shared<int>()),
SmartPointerEq{}));
}
TEST(HashValueTest, FunctionPointer) {
using Func = int (*)();
EXPECT_TRUE(is_hashable<Func>::value);
Func p1 = [] { return 2; }, p2 = [] { return 1; };
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(p1, p2, nullptr)));
}
struct WrapInTuple {
template <typename T>
std::tuple<int, T, size_t> operator()(const T& t) const {
return std::make_tuple(7, t, 0xdeadbeef);
}
};
absl::Cord FlatCord(absl::string_view sv) {
absl::Cord c(sv);
c.Flatten();
return c;
}
absl::Cord FragmentedCord(absl::string_view sv) {
if (sv.size() < 2) {
return absl::Cord(sv);
}
size_t halfway = sv.size() / 2;
std::vector<absl::string_view> parts = {sv.substr(0, halfway),
sv.substr(halfway)};
return absl::MakeFragmentedCord(parts);
}
TEST(HashValueTest, Strings) {
EXPECT_TRUE((is_hashable<std::string>::value));
const std::string small = "foo";
const std::string dup = "foofoo";
const std::string large = std::string(2048, 'x'); // multiple of chunk size
const std::string huge = std::string(5000, 'a'); // not a multiple
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple( //
std::string(), absl::string_view(), absl::Cord(), //
std::string(""), absl::string_view(""), absl::Cord(""), //
std::string(small), absl::string_view(small), absl::Cord(small), //
std::string(dup), absl::string_view(dup), absl::Cord(dup), //
std::string(large), absl::string_view(large), absl::Cord(large), //
std::string(huge), absl::string_view(huge), FlatCord(huge), //
FragmentedCord(huge))));
// Also check that nested types maintain the same hash.
const WrapInTuple t{};
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple( //
t(std::string()), t(absl::string_view()), t(absl::Cord()), //
t(std::string("")), t(absl::string_view("")), t(absl::Cord("")), //
t(std::string(small)), t(absl::string_view(small)), //
t(absl::Cord(small)), //
t(std::string(dup)), t(absl::string_view(dup)), t(absl::Cord(dup)), //
t(std::string(large)), t(absl::string_view(large)), //
t(absl::Cord(large)), //
t(std::string(huge)), t(absl::string_view(huge)), //
t(FlatCord(huge)), t(FragmentedCord(huge)))));
// Make sure that hashing a `const char*` does not use its string-value.
EXPECT_NE(SpyHash(static_cast<const char*>("ABC")),
SpyHash(absl::string_view("ABC")));
}
TEST(HashValueTest, WString) {
EXPECT_TRUE((is_hashable<std::wstring>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::wstring(), std::wstring(L"ABC"), std::wstring(L"ABC"),
std::wstring(L"Some other different string"),
std::wstring(L"Iñtërnâtiônàlizætiøn"))));
}
TEST(HashValueTest, U16String) {
EXPECT_TRUE((is_hashable<std::u16string>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::u16string(), std::u16string(u"ABC"), std::u16string(u"ABC"),
std::u16string(u"Some other different string"),
std::u16string(u"Iñtërnâtiônàlizætiøn"))));
}
TEST(HashValueTest, U32String) {
EXPECT_TRUE((is_hashable<std::u32string>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
std::u32string(), std::u32string(U"ABC"), std::u32string(U"ABC"),
std::u32string(U"Some other different string"),
std::u32string(U"Iñtërnâtiônàlizætiøn"))));
}
TEST(HashValueTest, StdArray) {
EXPECT_TRUE((is_hashable<std::array<int, 3>>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(std::array<int, 3>{}, std::array<int, 3>{{0, 23, 42}})));
}
TEST(HashValueTest, StdBitset) {
EXPECT_TRUE((is_hashable<std::bitset<257>>::value));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
{std::bitset<2>("00"), std::bitset<2>("01"), std::bitset<2>("10"),
std::bitset<2>("11")}));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
{std::bitset<5>("10101"), std::bitset<5>("10001"), std::bitset<5>()}));
constexpr int kNumBits = 256;
std::array<std::string, 6> bit_strings;
bit_strings.fill(std::string(kNumBits, '1'));
bit_strings[1][0] = '0';
bit_strings[2][1] = '0';
bit_strings[3][kNumBits / 3] = '0';
bit_strings[4][kNumBits - 2] = '0';
bit_strings[5][kNumBits - 1] = '0';
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
{std::bitset<kNumBits>(bit_strings[0].c_str()),
std::bitset<kNumBits>(bit_strings[1].c_str()),
std::bitset<kNumBits>(bit_strings[2].c_str()),
std::bitset<kNumBits>(bit_strings[3].c_str()),
std::bitset<kNumBits>(bit_strings[4].c_str()),
std::bitset<kNumBits>(bit_strings[5].c_str())}));
} // namespace
template <typename T>
class HashValueSequenceTest : public testing::Test {
};
TYPED_TEST_SUITE_P(HashValueSequenceTest);
TYPED_TEST_P(HashValueSequenceTest, BasicUsage) {
EXPECT_TRUE((is_hashable<TypeParam>::value));
using ValueType = typename TypeParam::value_type;
auto a = static_cast<ValueType>(0);
auto b = static_cast<ValueType>(23);
auto c = static_cast<ValueType>(42);
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(TypeParam(), TypeParam{}, TypeParam{a, b, c},
TypeParam{a, b}, TypeParam{b, c})));
}
REGISTER_TYPED_TEST_CASE_P(HashValueSequenceTest, BasicUsage);
using IntSequenceTypes =
testing::Types<std::deque<int>, std::forward_list<int>, std::list<int>,
std::vector<int>, std::vector<bool>, std::set<int>,
std::multiset<int>>;
INSTANTIATE_TYPED_TEST_CASE_P(My, HashValueSequenceTest, IntSequenceTypes);
// Private type that only supports AbslHashValue to make sure our chosen hash
// implementation is recursive within absl::Hash.
// It uses std::abs() on the value to provide different bitwise representations
// of the same logical value.
struct Private {
int i;
template <typename H>
friend H AbslHashValue(H h, Private p) {
return H::combine(std::move(h), std::abs(p.i));
}
friend bool operator==(Private a, Private b) {
return std::abs(a.i) == std::abs(b.i);
}
friend std::ostream& operator<<(std::ostream& o, Private p) {
return o << p.i;
}
};
// Test helper for combine_piecewise_buffer. It holds a string_view to the
// buffer-to-be-hashed. Its AbslHashValue specialization will split up its
// contents at the character offsets requested.
class PiecewiseHashTester {
public:
// Create a hash view of a buffer to be hashed contiguously.
explicit PiecewiseHashTester(absl::string_view buf)
: buf_(buf), piecewise_(false), split_locations_() {}
// Create a hash view of a buffer to be hashed piecewise, with breaks at the
// given locations.
PiecewiseHashTester(absl::string_view buf, std::set<size_t> split_locations)
: buf_(buf),
piecewise_(true),
split_locations_(std::move(split_locations)) {}
template <typename H>
friend H AbslHashValue(H h, const PiecewiseHashTester& p) {
if (!p.piecewise_) {
return H::combine_contiguous(std::move(h), p.buf_.data(), p.buf_.size());
}
absl::hash_internal::PiecewiseCombiner combiner;
if (p.split_locations_.empty()) {
h = combiner.add_buffer(std::move(h), p.buf_.data(), p.buf_.size());
return combiner.finalize(std::move(h));
}
size_t begin = 0;
for (size_t next : p.split_locations_) {
absl::string_view chunk = p.buf_.substr(begin, next - begin);
h = combiner.add_buffer(std::move(h), chunk.data(), chunk.size());
begin = next;
}
absl::string_view last_chunk = p.buf_.substr(begin);
if (!last_chunk.empty()) {
h = combiner.add_buffer(std::move(h), last_chunk.data(),
last_chunk.size());
}
return combiner.finalize(std::move(h));
}
private:
absl::string_view buf_;
bool piecewise_;
std::set<size_t> split_locations_;
};
// Dummy object that hashes as two distinct contiguous buffers, "foo" followed
// by "bar"
struct DummyFooBar {
template <typename H>
friend H AbslHashValue(H h, const DummyFooBar&) {
const char* foo = "foo";
const char* bar = "bar";
h = H::combine_contiguous(std::move(h), foo, 3);
h = H::combine_contiguous(std::move(h), bar, 3);
return h;
}
};
TEST(HashValueTest, CombinePiecewiseBuffer) {
absl::Hash<PiecewiseHashTester> hash;
// Check that hashing an empty buffer through the piecewise API works.
EXPECT_EQ(hash(PiecewiseHashTester("")), hash(PiecewiseHashTester("", {})));
// Similarly, small buffers should give consistent results
EXPECT_EQ(hash(PiecewiseHashTester("foobar")),
hash(PiecewiseHashTester("foobar", {})));
EXPECT_EQ(hash(PiecewiseHashTester("foobar")),
hash(PiecewiseHashTester("foobar", {3})));
// But hashing "foobar" in pieces gives a different answer than hashing "foo"
// contiguously, then "bar" contiguously.
EXPECT_NE(hash(PiecewiseHashTester("foobar", {3})),
absl::Hash<DummyFooBar>()(DummyFooBar{}));
// Test hashing a large buffer incrementally, broken up in several different
// ways. Arrange for breaks on and near the stride boundaries to look for
// off-by-one errors in the implementation.
//
// This test is run on a buffer that is a multiple of the stride size, and one
// that isn't.
for (size_t big_buffer_size : {1024 * 2 + 512, 1024 * 3}) {
SCOPED_TRACE(big_buffer_size);
std::string big_buffer;
for (int i = 0; i < big_buffer_size; ++i) {
// Arbitrary string
big_buffer.push_back(32 + (i * (i / 3)) % 64);
}
auto big_buffer_hash = hash(PiecewiseHashTester(big_buffer));
const int possible_breaks = 9;
size_t breaks[possible_breaks] = {1, 512, 1023, 1024, 1025,
1536, 2047, 2048, 2049};
for (unsigned test_mask = 0; test_mask < (1u << possible_breaks);
++test_mask) {
SCOPED_TRACE(test_mask);
std::set<size_t> break_locations;
for (int j = 0; j < possible_breaks; ++j) {
if (test_mask & (1u << j)) {
break_locations.insert(breaks[j]);
}
}
EXPECT_EQ(
hash(PiecewiseHashTester(big_buffer, std::move(break_locations))),
big_buffer_hash);
}
}
}
TEST(HashValueTest, PrivateSanity) {
// Sanity check that Private is working as the tests below expect it to work.
EXPECT_TRUE(is_hashable<Private>::value);
EXPECT_NE(SpyHash(Private{0}), SpyHash(Private{1}));
EXPECT_EQ(SpyHash(Private{1}), SpyHash(Private{1}));
}
TEST(HashValueTest, Optional) {
EXPECT_TRUE(is_hashable<absl::optional<Private>>::value);
using O = absl::optional<Private>;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(O{}, O{{1}}, O{{-1}}, O{{10}})));
}
TEST(HashValueTest, Variant) {
using V = absl::variant<Private, std::string>;
EXPECT_TRUE(is_hashable<V>::value);
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
V(Private{1}), V(Private{-1}), V(Private{2}), V("ABC"), V("BCD"))));
#if ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
struct S {};
EXPECT_FALSE(is_hashable<absl::variant<S>>::value);
#endif
}
TEST(HashValueTest, Maps) {
EXPECT_TRUE((is_hashable<std::map<int, std::string>>::value));
using M = std::map<int, std::string>;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
M{}, M{{0, "foo"}}, M{{1, "foo"}}, M{{0, "bar"}}, M{{1, "bar"}},
M{{0, "foo"}, {42, "bar"}}, M{{1, "foo"}, {42, "bar"}},
M{{1, "foo"}, {43, "bar"}}, M{{1, "foo"}, {43, "baz"}})));
using MM = std::multimap<int, std::string>;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
MM{}, MM{{0, "foo"}}, MM{{1, "foo"}}, MM{{0, "bar"}}, MM{{1, "bar"}},
MM{{0, "foo"}, {0, "bar"}}, MM{{0, "bar"}, {0, "foo"}},
MM{{0, "foo"}, {42, "bar"}}, MM{{1, "foo"}, {42, "bar"}},
MM{{1, "foo"}, {1, "foo"}, {43, "bar"}}, MM{{1, "foo"}, {43, "baz"}})));
}
TEST(HashValueTest, ReferenceWrapper) {
EXPECT_TRUE(is_hashable<std::reference_wrapper<Private>>::value);
Private p1{1}, p10{10};
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
p1, p10, std::ref(p1), std::ref(p10), std::cref(p1), std::cref(p10))));
EXPECT_TRUE(is_hashable<std::reference_wrapper<int>>::value);
int one = 1, ten = 10;
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
one, ten, std::ref(one), std::ref(ten), std::cref(one), std::cref(ten))));
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
std::make_tuple(std::tuple<std::reference_wrapper<int>>(std::ref(one)),
std::tuple<std::reference_wrapper<int>>(std::ref(ten)),
std::tuple<int>(one), std::tuple<int>(ten))));
}
template <typename T, typename = void>
struct IsHashCallable : std::false_type {};
template <typename T>
struct IsHashCallable<T, absl::void_t<decltype(std::declval<absl::Hash<T>>()(
std::declval<const T&>()))>> : std::true_type {};
template <typename T, typename = void>
struct IsAggregateInitializable : std::false_type {};
template <typename T>
struct IsAggregateInitializable<T, absl::void_t<decltype(T{})>>
: std::true_type {};
TEST(IsHashableTest, ValidHash) {
EXPECT_TRUE((is_hashable<int>::value));
EXPECT_TRUE(std::is_default_constructible<absl::Hash<int>>::value);
EXPECT_TRUE(std::is_copy_constructible<absl::Hash<int>>::value);
EXPECT_TRUE(std::is_move_constructible<absl::Hash<int>>::value);
EXPECT_TRUE(absl::is_copy_assignable<absl::Hash<int>>::value);
EXPECT_TRUE(absl::is_move_assignable<absl::Hash<int>>::value);
EXPECT_TRUE(IsHashCallable<int>::value);
EXPECT_TRUE(IsAggregateInitializable<absl::Hash<int>>::value);
}
#if ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
TEST(IsHashableTest, PoisonHash) {
struct X {};
EXPECT_FALSE((is_hashable<X>::value));
EXPECT_FALSE(std::is_default_constructible<absl::Hash<X>>::value);
EXPECT_FALSE(std::is_copy_constructible<absl::Hash<X>>::value);
EXPECT_FALSE(std::is_move_constructible<absl::Hash<X>>::value);
EXPECT_FALSE(absl::is_copy_assignable<absl::Hash<X>>::value);
EXPECT_FALSE(absl::is_move_assignable<absl::Hash<X>>::value);
EXPECT_FALSE(IsHashCallable<X>::value);
#if !defined(__GNUC__) || __GNUC__ < 9
// This doesn't compile on GCC 9.
EXPECT_FALSE(IsAggregateInitializable<absl::Hash<X>>::value);
#endif
}
#endif // ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
// Hashable types
//
// These types exist simply to exercise various AbslHashValue behaviors, so
// they are named by what their AbslHashValue overload does.
struct NoOp {
template <typename HashCode>
friend HashCode AbslHashValue(HashCode h, NoOp n) {
return h;
}
};
struct EmptyCombine {
template <typename HashCode>
friend HashCode AbslHashValue(HashCode h, EmptyCombine e) {
return HashCode::combine(std::move(h));
}
};
template <typename Int>
struct CombineIterative {
template <typename HashCode>
friend HashCode AbslHashValue(HashCode h, CombineIterative c) {
for (int i = 0; i < 5; ++i) {
h = HashCode::combine(std::move(h), Int(i));
}
return h;
}
};
template <typename Int>
struct CombineVariadic {
template <typename HashCode>
friend HashCode AbslHashValue(HashCode h, CombineVariadic c) {
return HashCode::combine(std::move(h), Int(0), Int(1), Int(2), Int(3),
Int(4));
}
};
enum class InvokeTag {
kUniquelyRepresented,
kHashValue,
#if ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
kLegacyHash,
#endif // ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
kStdHash,
kNone
};
template <InvokeTag T>
using InvokeTagConstant = std::integral_constant<InvokeTag, T>;
template <InvokeTag... Tags>
struct MinTag;
template <InvokeTag a, InvokeTag b, InvokeTag... Tags>
struct MinTag<a, b, Tags...> : MinTag<(a < b ? a : b), Tags...> {};
template <InvokeTag a>
struct MinTag<a> : InvokeTagConstant<a> {};
template <InvokeTag... Tags>
struct CustomHashType {
explicit CustomHashType(size_t val) : value(val) {}
size_t value;
};
template <InvokeTag allowed, InvokeTag... tags>
struct EnableIfContained
: std::enable_if<absl::disjunction<
std::integral_constant<bool, allowed == tags>...>::value> {};
template <
typename H, InvokeTag... Tags,
typename = typename EnableIfContained<InvokeTag::kHashValue, Tags...>::type>
H AbslHashValue(H state, CustomHashType<Tags...> t) {
static_assert(MinTag<Tags...>::value == InvokeTag::kHashValue, "");
return H::combine(std::move(state),
t.value + static_cast<int>(InvokeTag::kHashValue));
}
} // namespace
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace hash_internal {
template <InvokeTag... Tags>
struct is_uniquely_represented<
CustomHashType<Tags...>,
typename EnableIfContained<InvokeTag::kUniquelyRepresented, Tags...>::type>
: std::true_type {};
} // namespace hash_internal
ABSL_NAMESPACE_END
} // namespace absl
#if ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
namespace ABSL_INTERNAL_LEGACY_HASH_NAMESPACE {
template <InvokeTag... Tags>
struct hash<CustomHashType<Tags...>> {
template <InvokeTag... TagsIn, typename = typename EnableIfContained<
InvokeTag::kLegacyHash, TagsIn...>::type>
size_t operator()(CustomHashType<TagsIn...> t) const {
static_assert(MinTag<Tags...>::value == InvokeTag::kLegacyHash, "");
return t.value + static_cast<int>(InvokeTag::kLegacyHash);
}
};
} // namespace ABSL_INTERNAL_LEGACY_HASH_NAMESPACE
#endif // ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
namespace std {
template <InvokeTag... Tags> // NOLINT
struct hash<CustomHashType<Tags...>> {
template <InvokeTag... TagsIn, typename = typename EnableIfContained<
InvokeTag::kStdHash, TagsIn...>::type>
size_t operator()(CustomHashType<TagsIn...> t) const {
static_assert(MinTag<Tags...>::value == InvokeTag::kStdHash, "");
return t.value + static_cast<int>(InvokeTag::kStdHash);
}
};
} // namespace std
namespace {
template <typename... T>
void TestCustomHashType(InvokeTagConstant<InvokeTag::kNone>, T...) {
using type = CustomHashType<T::value...>;
SCOPED_TRACE(testing::PrintToString(std::vector<InvokeTag>{T::value...}));
EXPECT_TRUE(is_hashable<type>());
EXPECT_TRUE(is_hashable<const type>());
EXPECT_TRUE(is_hashable<const type&>());
const size_t offset = static_cast<int>(std::min({T::value...}));
EXPECT_EQ(SpyHash(type(7)), SpyHash(size_t{7 + offset}));
}
void TestCustomHashType(InvokeTagConstant<InvokeTag::kNone>) {
#if ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
// is_hashable is false if we don't support any of the hooks.
using type = CustomHashType<>;
EXPECT_FALSE(is_hashable<type>());
EXPECT_FALSE(is_hashable<const type>());
EXPECT_FALSE(is_hashable<const type&>());
#endif // ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
}
template <InvokeTag Tag, typename... T>
void TestCustomHashType(InvokeTagConstant<Tag> tag, T... t) {
constexpr auto next = static_cast<InvokeTag>(static_cast<int>(Tag) + 1);
TestCustomHashType(InvokeTagConstant<next>(), tag, t...);
TestCustomHashType(InvokeTagConstant<next>(), t...);
}
TEST(HashTest, CustomHashType) {
TestCustomHashType(InvokeTagConstant<InvokeTag{}>());
}
TEST(HashTest, NoOpsAreEquivalent) {
EXPECT_EQ(Hash<NoOp>()({}), Hash<NoOp>()({}));
EXPECT_EQ(Hash<NoOp>()({}), Hash<EmptyCombine>()({}));
}
template <typename T>
class HashIntTest : public testing::Test {
};
TYPED_TEST_SUITE_P(HashIntTest);
TYPED_TEST_P(HashIntTest, BasicUsage) {
EXPECT_NE(Hash<NoOp>()({}), Hash<TypeParam>()(0));
EXPECT_NE(Hash<NoOp>()({}),
Hash<TypeParam>()(std::numeric_limits<TypeParam>::max()));
if (std::numeric_limits<TypeParam>::min() != 0) {
EXPECT_NE(Hash<NoOp>()({}),
Hash<TypeParam>()(std::numeric_limits<TypeParam>::min()));
}
EXPECT_EQ(Hash<CombineIterative<TypeParam>>()({}),
Hash<CombineVariadic<TypeParam>>()({}));
}
REGISTER_TYPED_TEST_CASE_P(HashIntTest, BasicUsage);
using IntTypes = testing::Types<unsigned char, char, int, int32_t, int64_t, uint32_t,
uint64_t, size_t>;
INSTANTIATE_TYPED_TEST_CASE_P(My, HashIntTest, IntTypes);
struct StructWithPadding {
char c;
int i;
template <typename H>
friend H AbslHashValue(H hash_state, const StructWithPadding& s) {
return H::combine(std::move(hash_state), s.c, s.i);
}
};
static_assert(sizeof(StructWithPadding) > sizeof(char) + sizeof(int),
"StructWithPadding doesn't have padding");
static_assert(std::is_standard_layout<StructWithPadding>::value, "");
// This check has to be disabled because libstdc++ doesn't support it.
// static_assert(std::is_trivially_constructible<StructWithPadding>::value, "");
template <typename T>
struct ArraySlice {
T* begin;
T* end;
template <typename H>
friend H AbslHashValue(H hash_state, const ArraySlice& slice) {
for (auto t = slice.begin; t != slice.end; ++t) {
hash_state = H::combine(std::move(hash_state), *t);
}
return hash_state;
}
};
TEST(HashTest, HashNonUniquelyRepresentedType) {
// Create equal StructWithPadding objects that are known to have non-equal
// padding bytes.
static const size_t kNumStructs = 10;
unsigned char buffer1[kNumStructs * sizeof(StructWithPadding)];
std::memset(buffer1, 0, sizeof(buffer1));
auto* s1 = reinterpret_cast<StructWithPadding*>(buffer1);
unsigned char buffer2[kNumStructs * sizeof(StructWithPadding)];
std::memset(buffer2, 255, sizeof(buffer2));
auto* s2 = reinterpret_cast<StructWithPadding*>(buffer2);
for (int i = 0; i < kNumStructs; ++i) {
SCOPED_TRACE(i);
s1[i].c = s2[i].c = '0' + i;
s1[i].i = s2[i].i = i;
ASSERT_FALSE(memcmp(buffer1 + i * sizeof(StructWithPadding),
buffer2 + i * sizeof(StructWithPadding),
sizeof(StructWithPadding)) == 0)
<< "Bug in test code: objects do not have unequal"
<< " object representations";
}
EXPECT_EQ(Hash<StructWithPadding>()(s1[0]), Hash<StructWithPadding>()(s2[0]));
EXPECT_EQ(Hash<ArraySlice<StructWithPadding>>()({s1, s1 + kNumStructs}),
Hash<ArraySlice<StructWithPadding>>()({s2, s2 + kNumStructs}));
}
TEST(HashTest, StandardHashContainerUsage) {
std::unordered_map<int, std::string, Hash<int>> map = {{0, "foo"},
{42, "bar"}};
EXPECT_NE(map.find(0), map.end());
EXPECT_EQ(map.find(1), map.end());
EXPECT_NE(map.find(0u), map.end());
}
struct ConvertibleFromNoOp {
ConvertibleFromNoOp(NoOp) {} // NOLINT(runtime/explicit)
template <typename H>
friend H AbslHashValue(H hash_state, ConvertibleFromNoOp) {
return H::combine(std::move(hash_state), 1);
}
};
TEST(HashTest, HeterogeneousCall) {
EXPECT_NE(Hash<ConvertibleFromNoOp>()(NoOp()),
Hash<NoOp>()(NoOp()));
}
TEST(IsUniquelyRepresentedTest, SanityTest) {
using absl::hash_internal::is_uniquely_represented;
EXPECT_TRUE(is_uniquely_represented<unsigned char>::value);
EXPECT_TRUE(is_uniquely_represented<int>::value);
EXPECT_FALSE(is_uniquely_represented<bool>::value);
EXPECT_FALSE(is_uniquely_represented<int*>::value);
}
struct IntAndString {
int i;
std::string s;
template <typename H>
friend H AbslHashValue(H hash_state, IntAndString int_and_string) {
return H::combine(std::move(hash_state), int_and_string.s,
int_and_string.i);
}
};
TEST(HashTest, SmallValueOn64ByteBoundary) {
Hash<IntAndString>()(IntAndString{0, std::string(63, '0')});
}
struct TypeErased {
size_t n;
template <typename H>
friend H AbslHashValue(H hash_state, const TypeErased& v) {
v.HashValue(absl::HashState::Create(&hash_state));
return hash_state;
}
void HashValue(absl::HashState state) const {
absl::HashState::combine(std::move(state), n);
}
};
TEST(HashTest, TypeErased) {
EXPECT_TRUE((is_hashable<TypeErased>::value));
EXPECT_TRUE((is_hashable<std::pair<TypeErased, int>>::value));
EXPECT_EQ(SpyHash(TypeErased{7}), SpyHash(size_t{7}));
EXPECT_NE(SpyHash(TypeErased{7}), SpyHash(size_t{13}));
EXPECT_EQ(SpyHash(std::make_pair(TypeErased{7}, 17)),
SpyHash(std::make_pair(size_t{7}, 17)));
}
struct ValueWithBoolConversion {
operator bool() const { return false; }
int i;
};
} // namespace
namespace std {
template <>
struct hash<ValueWithBoolConversion> {
size_t operator()(ValueWithBoolConversion v) { return v.i; }
};
} // namespace std
namespace {
TEST(HashTest, DoesNotUseImplicitConversionsToBool) {
EXPECT_NE(absl::Hash<ValueWithBoolConversion>()(ValueWithBoolConversion{0}),
absl::Hash<ValueWithBoolConversion>()(ValueWithBoolConversion{1}));
}
} // namespace
