/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* 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 <folly/hash/Hash.h>
#include <stdint.h>
#include <random>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <folly/Conv.h>
#include <folly/MapUtil.h>
#include <folly/Random.h>
#include <folly/Range.h>
#include <folly/portability/GTest.h>
using namespace folly::hash;
TEST(Hash, Test128To64) {
constexpr uint64_t upper = 12345678910111213ULL;
constexpr uint64_t lower = 141516171819202122ULL;
EXPECT_NE(hash_128_to_64(upper, lower), hash_128_to_64(lower, upper));
EXPECT_EQ(
commutative_hash_128_to_64(upper, lower),
commutative_hash_128_to_64(lower, upper));
}
TEST(Hash, Fnv32) {
const char* s1 = "hello, world!";
const uint32_t s1_res = 3605494790UL;
EXPECT_EQ(fnv32(s1), s1_res);
EXPECT_EQ(fnv32(s1), fnv32_buf(s1, strlen(s1)));
const char* s2 = "monkeys! m0nk3yz! ev3ry \\/\\/here~~~~";
const uint32_t s2_res = 1270448334UL;
EXPECT_EQ(fnv32(s2), s2_res);
EXPECT_EQ(fnv32(s2), fnv32_buf(s2, strlen(s2)));
const char* s3 = "";
const uint32_t s3_res = 2166136261UL;
EXPECT_EQ(fnv32(s3), s3_res);
EXPECT_EQ(fnv32(s3), fnv32_buf(s3, strlen(s3)));
const uint8_t s4_data[] = {0xFF, 0xFF, 0xFF, 0x00};
const char* s4 = reinterpret_cast<const char*>(s4_data);
const uint32_t s4_res = 2420936562UL;
EXPECT_EQ(fnv32(s4), s4_res);
EXPECT_EQ(fnv32(s4), fnv32_buf(s4, strlen(s4)));
}
TEST(Hash, Fnv64) {
const char* s1 = "hello, world!";
const uint64_t s1_res = 13991426986746681734ULL;
EXPECT_EQ(fnv64(s1), s1_res);
EXPECT_EQ(fnv64(s1), fnv64_buf(s1, strlen(s1)));
const char* s2 = "monkeys! m0nk3yz! ev3ry \\/\\/here~~~~";
const uint64_t s2_res = 6091394665637302478ULL;
EXPECT_EQ(fnv64(s2), s2_res);
EXPECT_EQ(fnv64(s2), fnv64_buf(s2, strlen(s2)));
const char* s3 = "";
const uint64_t s3_res = 14695981039346656037ULL;
EXPECT_EQ(fnv64(s3), s3_res);
EXPECT_EQ(fnv64(s3), fnv64_buf(s3, strlen(s3)));
const uint8_t s4_data[] = {0xFF, 0xFF, 0xFF, 0x00};
const char* s4 = reinterpret_cast<const char*>(s4_data);
const uint64_t s4_res = 2787597222566293202ULL;
EXPECT_EQ(fnv64(s4), s4_res);
EXPECT_EQ(fnv64(s4), fnv64_buf(s4, strlen(s4)));
// note: Use fnv64_buf to make a single hash value from multiple
// fields/datatypes.
const char* t4_a = "E Pluribus";
int64_t t4_b = 0xF1E2D3C4B5A69788;
int32_t t4_c = 0xAB12CD34;
const char* t4_d = "Unum";
uint64_t t4_res = 15571330457339273965ULL;
uint64_t t4_hash1 = fnv64_buf(t4_a, strlen(t4_a));
uint64_t t4_hash2 =
fnv64_buf(reinterpret_cast<void*>(&t4_b), sizeof(int64_t), t4_hash1);
uint64_t t4_hash3 =
fnv64_buf(reinterpret_cast<void*>(&t4_c), sizeof(int32_t), t4_hash2);
uint64_t t4_hash4 = fnv64_buf(t4_d, strlen(t4_d), t4_hash3);
EXPECT_EQ(t4_hash4, t4_res);
// note: These are probabalistic, not determinate, but c'mon.
// These hash values should be different, or something's not
// working.
EXPECT_NE(t4_hash1, t4_hash4);
EXPECT_NE(t4_hash2, t4_hash4);
EXPECT_NE(t4_hash3, t4_hash4);
}
TEST(Hash, Hsieh32) {
const char* s1 = "hello, world!";
const uint32_t s1_res = 2918802987ul;
EXPECT_EQ(hsieh_hash32(s1), s1_res);
EXPECT_EQ(hsieh_hash32(s1), hsieh_hash32_buf(s1, strlen(s1)));
const char* s2 = "monkeys! m0nk3yz! ev3ry \\/\\/here~~~~";
const uint32_t s2_res = 47373213ul;
EXPECT_EQ(hsieh_hash32(s2), s2_res);
EXPECT_EQ(hsieh_hash32(s2), hsieh_hash32_buf(s2, strlen(s2)));
const char* s3 = "";
const uint32_t s3_res = 0;
EXPECT_EQ(hsieh_hash32(s3), s3_res);
EXPECT_EQ(hsieh_hash32(s3), hsieh_hash32_buf(s3, strlen(s3)));
}
TEST(Hash, TWangMix64) {
uint64_t i1 = 0x78a87873e2d31dafULL;
uint64_t i1_res = 3389151152926383528ULL;
EXPECT_EQ(i1_res, twang_mix64(i1));
EXPECT_EQ(i1, twang_unmix64(i1_res));
uint64_t i2 = 0x0123456789abcdefULL;
uint64_t i2_res = 3061460455458984563ull;
EXPECT_EQ(i2_res, twang_mix64(i2));
EXPECT_EQ(i2, twang_unmix64(i2_res));
}
namespace {
void checkTWang(uint64_t r) {
uint64_t result = twang_mix64(r);
EXPECT_EQ(r, twang_unmix64(result));
}
} // namespace
TEST(Hash, TWangUnmix64) {
// We'll try (1 << i), (1 << i) + 1, (1 << i) - 1
for (int i = 1; i < 64; i++) {
checkTWang((uint64_t(1) << i) - 1);
checkTWang(uint64_t(1) << i);
checkTWang((uint64_t(1) << i) + 1);
}
}
TEST(Hash, TWang32From64) {
uint64_t i1 = 0x78a87873e2d31dafULL;
uint32_t i1_res = 1525586863ul;
EXPECT_EQ(twang_32from64(i1), i1_res);
uint64_t i2 = 0x0123456789abcdefULL;
uint32_t i2_res = 2918899159ul;
EXPECT_EQ(twang_32from64(i2), i2_res);
}
TEST(Hash, JenkinsRevMix32) {
uint32_t i1 = 3805486511ul;
uint32_t i1_res = 381808021ul;
EXPECT_EQ(i1_res, jenkins_rev_mix32(i1));
EXPECT_EQ(i1, jenkins_rev_unmix32(i1_res));
uint32_t i2 = 2309737967ul;
uint32_t i2_res = 1834777923ul;
EXPECT_EQ(i2_res, jenkins_rev_mix32(i2));
EXPECT_EQ(i2, jenkins_rev_unmix32(i2_res));
}
namespace {
void checkJenkins(uint32_t r) {
uint32_t result = jenkins_rev_mix32(r);
EXPECT_EQ(r, jenkins_rev_unmix32(result));
}
} // namespace
TEST(Hash, JenkinsRevUnmix32) {
// We'll try (1 << i), (1 << i) + 1, (1 << i) - 1
for (int i = 1; i < 32; i++) {
checkJenkins((1U << i) - 1);
checkJenkins(1U << i);
checkJenkins((1U << i) + 1);
}
}
TEST(Hash, hasher) {
// Basically just confirms that things compile ok.
std::unordered_map<int32_t, int32_t, folly::hasher<int32_t>> m;
m.insert(std::make_pair(4, 5));
EXPECT_EQ(get_default(m, 4), 5);
}
TEST(Hash, integralTypes) {
// Basically just confirms that things compile ok.
std::unordered_set<size_t> hashes;
folly::Hash hasher;
hashes.insert(hasher((char)1));
hashes.insert(hasher((signed char)2));
hashes.insert(hasher((unsigned char)3));
hashes.insert(hasher((short)4));
hashes.insert(hasher((signed short)5));
hashes.insert(hasher((unsigned short)6));
hashes.insert(hasher((int)7));
hashes.insert(hasher((signed int)8));
hashes.insert(hasher((unsigned int)9));
hashes.insert(hasher((long)10));
hashes.insert(hasher((signed long)11));
hashes.insert(hasher((unsigned long)12));
hashes.insert(hasher((long long)13));
hashes.insert(hasher((signed long long)14));
hashes.insert(hasher((unsigned long long)15));
hashes.insert(hasher((int8_t)16));
hashes.insert(hasher((uint8_t)17));
hashes.insert(hasher((int16_t)18));
hashes.insert(hasher((uint16_t)19));
hashes.insert(hasher((int32_t)20));
hashes.insert(hasher((uint32_t)21));
hashes.insert(hasher((int64_t)22));
hashes.insert(hasher((uint64_t)23));
hashes.insert(hasher((size_t)24));
size_t setSize = 24;
#if FOLLY_HAVE_INT128_T
hashes.insert(hasher((__int128_t)25));
hashes.insert(hasher((__uint128_t)26));
setSize += 2;
#endif
EXPECT_EQ(setSize, hashes.size());
}
namespace {
enum class TestEnum {
MIN = 0,
ITEM = 1,
MAX = 2,
};
enum class TestBigEnum : uint64_t {
ITEM = 1,
};
struct TestStruct {};
} // namespace
namespace std {
template <>
struct hash<TestEnum> {
std::size_t operator()(TestEnum const& e) const noexcept {
return hash<int>()(static_cast<int>(e));
}
};
template <>
struct hash<TestStruct> {
std::size_t operator()(TestStruct const&) const noexcept { return 0; }
};
} // namespace std
namespace {
thread_local size_t allocatedMemorySize{0};
template <class T>
class TestAlloc {
public:
using Alloc = std::allocator<T>;
using AllocTraits = std::allocator_traits<Alloc>;
using value_type = typename AllocTraits::value_type;
using pointer = typename AllocTraits::pointer;
using const_pointer = typename AllocTraits::const_pointer;
using reference = value_type&;
using const_reference = value_type const&;
using size_type = typename AllocTraits::size_type;
using propagate_on_container_swap = std::true_type;
using propagate_on_container_copy_assignment = std::true_type;
using propagate_on_container_move_assignment = std::true_type;
TestAlloc() {}
template <class T2>
TestAlloc(TestAlloc<T2> const& other) noexcept : a_(other.a_) {}
template <class T2>
TestAlloc& operator=(TestAlloc<T2> const& other) noexcept {
a_ = other.a_;
return *this;
}
template <class T2>
TestAlloc(TestAlloc<T2>&& other) noexcept : a_(std::move(other.a_)) {}
template <class T2>
TestAlloc& operator=(TestAlloc<T2>&& other) noexcept {
a_ = std::move(other.a_);
return *this;
}
static size_t getAllocatedMemorySize() { return allocatedMemorySize; }
static void resetTracking() { allocatedMemorySize = 0; }
T* allocate(size_t n) {
allocatedMemorySize += n * sizeof(T);
return a_.allocate(n);
}
void deallocate(T* p, size_t n) {
allocatedMemorySize -= n * sizeof(T);
a_.deallocate(p, n);
}
private:
std::allocator<T> a_;
template <class U>
friend class TestAlloc;
};
template <class T1, class T2>
bool operator==(TestAlloc<T1> const&, TestAlloc<T2> const&) {
return true;
}
template <class T1, class T2>
bool operator!=(TestAlloc<T1> const&, TestAlloc<T2> const&) {
return false;
}
template <class M, class A>
std::vector<size_t> getStats(size_t iter) {
std::vector<size_t> ret;
ret.reserve(iter);
A::resetTracking();
M m;
ret.push_back(A::getAllocatedMemorySize());
for (size_t i = 1; i < iter; ++i) {
m.insert(std::make_pair(
folly::to<typename M::key_type>(i), typename M::mapped_type{}));
ret.push_back(A::getAllocatedMemorySize());
}
return ret;
}
template <typename K, typename V, typename H>
void testNoCachedHashCode() {
using A = TestAlloc<std::pair<const K, V>>;
using M = std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, A>;
using MActual = std::unordered_map<K, V, H, std::equal_to<K>, A>;
constexpr int kIter = 10;
auto expected = getStats<M, A>(kIter);
auto actual = getStats<MActual, A>(kIter);
ASSERT_EQ(expected.size(), actual.size());
for (size_t i = 0; i < expected.size(); ++i) {
ASSERT_EQ(expected[i], actual[i]);
}
}
} // namespace
TEST(Hash, noCachedHashCode) {
testNoCachedHashCode<bool, char, folly::hasher<bool>>();
testNoCachedHashCode<int, char, folly::hasher<int>>();
testNoCachedHashCode<double, char, folly::hasher<double>>();
testNoCachedHashCode<TestEnum, char, folly::hasher<TestEnum>>();
testNoCachedHashCode<bool, std::string, folly::Hash>();
testNoCachedHashCode<int, std::string, folly::Hash>();
testNoCachedHashCode<double, std::string, folly::Hash>();
testNoCachedHashCode<TestEnum, std::string, folly::Hash>();
}
TEST(Hash, integerConversion) {
folly::hasher<uint64_t> h;
uint64_t k = 10;
EXPECT_EQ(h(k), h(10));
}
#if FOLLY_HAVE_INT128_T
TEST(Hash, int128StdHash) {
std::unordered_set<__int128> hs;
hs.insert(__int128_t{1});
hs.insert(__int128_t{2});
EXPECT_EQ(2, hs.size());
std::set<unsigned __int128> s;
s.insert(static_cast<unsigned __int128>(1));
s.insert(static_cast<unsigned __int128>(2));
EXPECT_EQ(2, s.size());
}
#endif
TEST(Hash, floatTypes) {
folly::Hash hasher;
EXPECT_EQ(hasher(0.0f), hasher(-0.0f));
EXPECT_EQ(hasher(0.0), hasher(-0.0));
// Basically just confirms that things compile ok.
std::unordered_set<size_t> hashes;
hashes.insert(hasher(0.0f));
hashes.insert(hasher(0.1f));
hashes.insert(hasher(0.2));
hashes.insert(hasher(0.2f));
hashes.insert(hasher(-0.3));
hashes.insert(hasher(-0.3f));
EXPECT_EQ(6, hashes.size());
}
// Not a full hasher since only handles one type
class TestHasher {
public:
size_t operator()(const std::pair<int, int>& p) const {
return p.first + p.second;
}
};
template <typename T, typename... Ts>
size_t hash_combine_test(const T& t, const Ts&... ts) {
return hash_combine_generic(TestHasher{}, t, ts...);
}
TEST(Hash, pair) {
auto a = std::make_pair(1, 2);
auto b = std::make_pair(3, 4);
auto c = std::make_pair(1, 2);
auto d = std::make_pair(2, 1);
EXPECT_EQ(hash_combine(a), hash_combine(c));
EXPECT_NE(hash_combine(b), hash_combine(c));
EXPECT_NE(hash_combine(d), hash_combine(c));
// With composition
EXPECT_EQ(hash_combine(a, b), hash_combine(c, b));
// Test order dependence
EXPECT_NE(hash_combine(a, b), hash_combine(b, a));
// Test with custom hasher
EXPECT_EQ(hash_combine_test(a), hash_combine_test(c));
// 3 + 4 != 1 + 2
EXPECT_NE(hash_combine_test(b), hash_combine_test(c));
// This time, thanks to a terrible hash function, these are equal
EXPECT_EQ(hash_combine_test(d), hash_combine_test(c));
// With composition
EXPECT_EQ(hash_combine_test(a, b), hash_combine_test(c, b));
// Test order dependence
EXPECT_NE(hash_combine_test(a, b), hash_combine_test(b, a));
// Again, 1 + 2 == 2 + 1
EXPECT_EQ(hash_combine_test(a, b), hash_combine_test(d, b));
}
TEST(Hash, hashCombine) {
EXPECT_TRUE(noexcept(hash_combine(1, 2)));
EXPECT_NE(hash_combine(1, 2), hash_combine(2, 1));
}
TEST(Hash, hashBool) {
const auto hash = folly::Hash();
EXPECT_NE(hash(true), hash(false));
}
TEST(Hash, hashBool10) {
const auto hash = folly::Hash();
std::set<size_t> values;
for (bool b1 : {false, true}) {
for (bool b2 : {false, true}) {
for (bool b3 : {false, true}) {
for (bool b4 : {false, true}) {
for (bool b5 : {false, true}) {
for (bool b6 : {false, true}) {
for (bool b7 : {false, true}) {
for (bool b8 : {false, true}) {
for (bool b9 : {false, true}) {
for (bool b10 : {false, true}) {
values.insert(
hash(b1, b2, b3, b4, b5, b6, b7, b8, b9, b10));
}
}
}
}
}
}
}
}
}
}
EXPECT_EQ(values.size(), 1 << 10);
}
TEST(Hash, stdTuple) {
typedef std::tuple<int64_t, std::string, int32_t> tuple3;
tuple3 t(42, "foo", 1);
std::unordered_map<tuple3, std::string> m;
m[t] = "bar";
EXPECT_EQ("bar", m[t]);
}
TEST(Hash, stdEmptyTuple) {
std::unordered_map<std::tuple<>, std::string, folly::Hash> m;
m[{}] = "foo";
EXPECT_EQ(m[{}], "foo");
folly::hasher<std::tuple<>> h;
EXPECT_EQ(h({}), 0);
}
TEST(Hash, enumType) {
const auto hash = folly::Hash();
enum class Enum32 : int32_t { Foo, Bar };
EXPECT_EQ(hash(static_cast<int32_t>(Enum32::Foo)), hash(Enum32::Foo));
EXPECT_EQ(hash(static_cast<int32_t>(Enum32::Bar)), hash(Enum32::Bar));
EXPECT_NE(hash(Enum32::Foo), hash(Enum32::Bar));
std::unordered_map<Enum32, std::string, folly::Hash> m32;
m32[Enum32::Foo] = "foo";
EXPECT_EQ("foo", m32[Enum32::Foo]);
enum class Enum64 : int64_t { Foo, Bar };
EXPECT_EQ(hash(static_cast<int64_t>(Enum64::Foo)), hash(Enum64::Foo));
EXPECT_EQ(hash(static_cast<int64_t>(Enum64::Bar)), hash(Enum64::Bar));
EXPECT_NE(hash(Enum64::Foo), hash(Enum64::Bar));
std::unordered_map<Enum64, std::string, folly::Hash> m64;
m64[Enum64::Foo] = "foo";
EXPECT_EQ("foo", m64[Enum64::Foo]);
}
TEST(Hash, pairFollyHash) {
typedef std::pair<int64_t, int32_t> pair2;
pair2 p(42, 1);
std::unordered_map<pair2, std::string, folly::Hash> m;
m[p] = "bar";
EXPECT_EQ("bar", m[p]);
}
TEST(Hash, tupleFollyHash) {
typedef std::tuple<int64_t, int32_t, int32_t> tuple3;
tuple3 t(42, 1, 1);
std::unordered_map<tuple3, std::string, folly::Hash> m;
m[t] = "bar";
EXPECT_EQ("bar", m[t]);
}
namespace {
template <class T>
size_t hash_vector(const std::vector<T>& v) {
return hash_range(v.begin(), v.end());
}
} // namespace
TEST(Hash, hashRange) {
EXPECT_EQ(hash_vector<int32_t>({1, 2}), hash_vector<int16_t>({1, 2}));
EXPECT_NE(hash_vector<int>({2, 1}), hash_vector<int>({1, 2}));
EXPECT_EQ(hash_vector<int>({}), hash_vector<float>({}));
}
TEST(Hash, commutativeHashCombine) {
EXPECT_EQ(
commutative_hash_combine_value_generic(
folly::Hash{}(12345ul), folly::Hash{}, 6789ul),
commutative_hash_combine_value_generic(
folly::Hash{}(6789ul), folly::Hash{}, 12345ul));
std::vector<int> v = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
std::random_device rd;
std::mt19937 g(rd());
auto h = commutative_hash_combine_range(v.begin(), v.end());
for (int i = 0; i < 100; i++) {
std::shuffle(v.begin(), v.end(), g);
EXPECT_EQ(h, commutative_hash_combine_range(v.begin(), v.end()));
}
EXPECT_NE(
h,
commutative_hash_combine_range_generic(
/* seed = */ 0xdeadbeef, folly::Hash{}, v.begin(), v.end()));
EXPECT_NE(
h, commutative_hash_combine_range(v.begin(), v.begin() + (v.size() - 1)));
EXPECT_EQ(h, commutative_hash_combine(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
EXPECT_EQ(h, commutative_hash_combine(10, 2, 3, 4, 5, 6, 7, 8, 9, 1));
EXPECT_EQ(
commutative_hash_combine(12345, 6789),
commutative_hash_combine(6789, 12345));
}
TEST(Hash, stdTupleDifferentHash) {
typedef std::tuple<int64_t, std::string, int32_t> tuple3;
tuple3 t1(42, "foo", 1);
tuple3 t2(9, "bar", 3);
tuple3 t3(42, "foo", 3);
EXPECT_NE(std::hash<tuple3>()(t1), std::hash<tuple3>()(t2));
EXPECT_NE(std::hash<tuple3>()(t1), std::hash<tuple3>()(t3));
}
TEST(Hash, Strings) {
using namespace folly;
StringPiece a1 = "10050517", b1 = "51107032", a2 = "10050518",
b2 = "51107033", a3 = "10050519", b3 = "51107034",
a4 = "10050525", b4 = "51107040";
Range<const wchar_t*> w1 = range(L"10050517"), w2 = range(L"51107032"),
w3 = range(L"10050518"), w4 = range(L"51107033");
Hash h2;
EXPECT_NE(h2(a1), h2(b1));
EXPECT_NE(h2(a1), h2(b1));
EXPECT_NE(h2(a2), h2(b2));
EXPECT_NE(h2(a3), h2(b3));
EXPECT_NE(h2(ByteRange(a1)), h2(ByteRange(b1)));
EXPECT_NE(h2(ByteRange(a2)), h2(ByteRange(b2)));
EXPECT_NE(h2(ByteRange(a3)), h2(ByteRange(b3)));
EXPECT_NE(h2(ByteRange(a4)), h2(ByteRange(b4)));
EXPECT_NE(h2(w1), h2(w2));
EXPECT_NE(h2(w1), h2(w3));
EXPECT_NE(h2(w2), h2(w4));
// Check compatibility with std::string.
EXPECT_EQ(h2(a1), h2(a1.str()));
EXPECT_EQ(h2(a2), h2(a2.str()));
EXPECT_EQ(h2(a3), h2(a3.str()));
EXPECT_EQ(h2(a4), h2(a4.str()));
// Check compatibility with std::string_view.
EXPECT_EQ(h2(a1), h2(std::string_view{a1}));
EXPECT_EQ(h2(a2), h2(std::string_view{a2}));
EXPECT_EQ(h2(a3), h2(std::string_view{a3}));
EXPECT_EQ(h2(a4), h2(std::string_view{a4}));
}
namespace {
void deletePointer(const std::unique_ptr<std::string>&) {}
void deletePointer(const std::shared_ptr<std::string>&) {}
void deletePointer(std::string* pointer) {
delete pointer;
}
template <template <typename...> class PtrType>
void pointerTestWithFollyHash() {
std::unordered_set<PtrType<std::string>, folly::Hash> set;
for (auto i = 0; i < 1000; ++i) {
auto random = PtrType<std::string>{
new std::string{folly::to<std::string>(folly::Random::rand64())}};
set.insert(std::move(random));
}
for (auto& pointer : set) {
EXPECT_TRUE(set.find(pointer) != set.end());
deletePointer(pointer);
}
}
template <typename T>
using Pointer = T*;
} // namespace
TEST(Hash, UniquePtr) {
pointerTestWithFollyHash<std::unique_ptr>();
}
TEST(Hash, SharedPtr) {
pointerTestWithFollyHash<std::shared_ptr>();
}
TEST(Hash, Pointer) {
pointerTestWithFollyHash<Pointer>();
EXPECT_TRUE(
(std::is_same<
folly::hasher<std::string*>::folly_is_avalanching,
folly::hasher<std::unique_ptr<std::string>>::folly_is_avalanching>::
value));
EXPECT_TRUE(
(std::is_same<
folly::hasher<std::string*>::folly_is_avalanching,
folly::hasher<std::shared_ptr<std::string>>::folly_is_avalanching>::
value));
}
struct FNVTestParam {
std::string in;
uint64_t out;
};
class FNVTest : public ::testing::TestWithParam<FNVTestParam> {};
TEST_P(FNVTest, Fnva64Buf) {
EXPECT_EQ(
GetParam().out, fnva64_buf(GetParam().in.data(), GetParam().in.size()));
}
TEST_P(FNVTest, Fnva64) {
EXPECT_EQ(GetParam().out, fnva64(GetParam().in));
}
TEST_P(FNVTest, Fnva64Partial) {
size_t partialLen = GetParam().in.size() / 2;
auto data = GetParam().in.data();
auto partial = fnva64_buf(data, partialLen);
EXPECT_EQ(
GetParam().out,
fnva64_buf(
data + partialLen, GetParam().in.size() - partialLen, partial));
}
// Taken from http://www.isthe.com/chongo/src/fnv/test_fnv.c
INSTANTIATE_TEST_SUITE_P(
FNVTesting,
FNVTest,
::testing::Values(
FNVTestParam{
"foobar", // 11
0x85944171f73967e8},
FNVTestParam{
"chongo was here!\n", // 39
0x46810940eff5f915},
FNVTestParam{
"127.0.0.3", // 106,
0xaabafc7104d91158},
FNVTestParam{
"http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash", // 126
0xd9b957fb7fe794c5},
FNVTestParam{
"http://norvig.com/21-days.html", // 136
0x07aaa640476e0b9a}));
//////// static checks
static constexpr bool k32Bit = sizeof(std::size_t) == 4;
static_assert(!folly::IsAvalanchingHasher<std::hash<int>, int>::value, "");
static_assert(
!folly::IsAvalanchingHasher<std::hash<char const*>, char const*>::value,
"");
static_assert(!folly::IsAvalanchingHasher<std::hash<float>, float>::value, "");
static_assert(
!folly::IsAvalanchingHasher<std::hash<double>, double>::value, "");
static_assert(
!folly::IsAvalanchingHasher<std::hash<long double>, long double>::value,
"");
static_assert(
folly::IsAvalanchingHasher<std::hash<std::string>, std::string>::value, "");
static_assert(
!folly::IsAvalanchingHasher<std::hash<TestEnum>, TestEnum>::value, "");
static_assert(
!folly::IsAvalanchingHasher<std::hash<TestStruct>, TestStruct>::value, "");
static_assert(
!folly::IsAvalanchingHasher<folly::transparent<std::hash<int>>, int>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::transparent<std::hash<std::string>>,
std::string>::value,
"");
// these come from folly/hash/Hash.h
static_assert(
folly::IsAvalanchingHasher<
std::hash<std::pair<int, int>>,
std::pair<int, int>>::value,
"");
static_assert(
!folly::IsAvalanchingHasher<std::hash<std::tuple<int>>, std::tuple<int>>::
value,
"");
static_assert(
folly::IsAvalanchingHasher<
std::hash<std::tuple<std::string>>,
std::tuple<std::string>>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
std::hash<std::tuple<int, int>>,
std::tuple<int, int>>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
std::hash<std::tuple<int, int, int>>,
std::tuple<int, int, int>>::value,
"");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, uint8_t>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, char>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, uint16_t>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, int16_t>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, uint32_t>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, int32_t>::value, "");
static_assert(folly::IsAvalanchingHasher<folly::Hash, uint64_t>::value, "");
static_assert(folly::IsAvalanchingHasher<folly::Hash, int64_t>::value, "");
static_assert(
folly::IsAvalanchingHasher<folly::Hash, folly::StringPiece>::value, "");
static_assert(folly::IsAvalanchingHasher<folly::Hash, std::string>::value, "");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::Hash, TestEnum>::value, "");
static_assert(folly::IsAvalanchingHasher<folly::Hash, TestBigEnum>::value, "");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<uint8_t>, uint8_t>::value,
"");
static_assert(
k32Bit == folly::IsAvalanchingHasher<folly::hasher<char>, char>::value, "");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<uint16_t>, uint16_t>::value,
"");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<int16_t>, int16_t>::value,
"");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<uint32_t>, uint32_t>::value,
"");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<int32_t>, int32_t>::value,
"");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<uint64_t>, uint64_t>::value, "");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<int64_t>, int64_t>::value, "");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<float>, float>::value, "");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<double>, double>::value, "");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<std::string>, std::string>::value,
"");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<folly::StringPiece>, std::string>::
value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::hasher<folly::StringPiece>,
folly::StringPiece>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::transparent<folly::hasher<folly::StringPiece>>,
folly::StringPiece>::value,
"");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<std::string>, std::string>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::hasher<std::pair<int, int>>,
std::pair<int, int>>::value,
"");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<
folly::hasher<std::tuple<int>>,
std::tuple<int>>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::hasher<std::tuple<std::string>>,
std::tuple<std::string>>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::hasher<std::tuple<int, int>>,
std::tuple<int, int>>::value,
"");
static_assert(
folly::IsAvalanchingHasher<
folly::hasher<std::tuple<int, int, int>>,
std::tuple<int, int, int>>::value,
"");
static_assert(
k32Bit ==
folly::IsAvalanchingHasher<folly::hasher<TestEnum>, TestEnum>::value,
"");
static_assert(
folly::IsAvalanchingHasher<folly::hasher<TestBigEnum>, TestBigEnum>::value,
"");
//////// dynamic checks
namespace {
template <typename H, typename T, typename F>
void verifyAvalanching(T initialValue, F const& advance) {
// This doesn't check probabilities, but does verify that every bit
// changed independently of every other bit, in both directions, when
// traversing a sequence of dependent changes. Note that it is NOT
// sufficient to just use a random sequence here, because even the
// identity function will pass. As constructed this will require
// 2^63 steps to complete for an identity hash, because none of the
// transitions with on == 63 will occur until then.
H const hasher;
constexpr std::size_t N = sizeof(decltype(hasher(initialValue))) * 8;
// seen[i][j] if we have seen i flip on at the same time as j went off
bool seen[N][N] = {};
std::size_t unseenCount = N * (N - 1);
auto v = initialValue;
auto h = hasher(v);
std::size_t steps = 0;
// wait for 95% coverage
while (unseenCount > (N * (N - 1)) / 95) {
++steps;
auto hPrev = h;
advance(v);
h = hasher(v);
uint64_t delta = hPrev ^ h;
for (std::size_t i = 0; i < N - 1; ++i) {
if (((delta >> i) & 1) == 0) {
continue;
}
// we know i flipped
for (std::size_t j = i + 1; j < N; ++j) {
if (((delta >> j) & 1) == 0) {
continue;
}
// we know j flipped
bool iOn = ((hPrev >> i) & 1) == 0;
bool jOn = ((hPrev >> j) & 1) == 0;
if (iOn != jOn) {
auto on = iOn ? i : j;
auto off = iOn ? j : i;
if (!seen[on][off]) {
seen[on][off] = true;
--unseenCount;
}
}
}
}
// we should actually only need a couple hundred
ASSERT_LT(steps, 1000) << unseenCount << " of " << (N * (N - 1))
<< " pair transitions unseen";
}
}
} // namespace
TEST(Traits, stdHashPairAvalances) {
verifyAvalanching<std::hash<std::pair<int, int>>>(
std::make_pair(0, 0), [](std::pair<int, int>& v) { v.first++; });
}
TEST(Traits, stdHashTuple2Avalances) {
verifyAvalanching<std::hash<std::tuple<int, int>>>(
std::make_tuple(0, 0),
[](std::tuple<int, int>& v) { std::get<0>(v) += 1; });
}
TEST(Traits, stdHashStringAvalances) {
verifyAvalanching<std::hash<std::string>, std::string>(
"00000000000000000000000000000", [](std::string& str) {
std::size_t i = 0;
while (str[i] == '1') {
str[i] = '0';
++i;
}
str[i] = '1';
});
}
TEST(Traits, follyHashUint64Avalances) {
verifyAvalanching<folly::Hash>(uint64_t{0}, [](uint64_t& v) { v++; });
}
TEST(Traits, follyHasherInt64Avalances) {
verifyAvalanching<folly::hasher<int64_t>>(
int64_t{0}, [](int64_t& v) { v++; });
}
TEST(Traits, follyHasherFloatAvalanches) {
verifyAvalanching<folly::hasher<float>>(0.0f, [](float& v) { v += 1; });
}
TEST(Traits, follyHasherDoubleAvalanches) {
verifyAvalanching<folly::hasher<double>>(0.0, [](double& v) { v += 1; });
}
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