///////////////////////// ankerl::unordered_dense::{map, set} /////////////////////////
// A fast & densely stored hashmap and hashset based on robin-hood backward shift deletion.
// Version 1.1.0
// https://github.com/martinus/unordered_dense
//
// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
// SPDX-License-Identifier: MIT
// Copyright (c) 2022 Martin Leitner-Ankerl <martin.ankerl@gmail.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#ifndef ANKERL_UNORDERED_DENSE_H
#define ANKERL_UNORDERED_DENSE_H
// see https://semver.org/spec/v2.0.0.html
#define ANKERL_UNORDERED_DENSE_VERSION_MAJOR 1 // incompatible API changes
#define ANKERL_UNORDERED_DENSE_VERSION_MINOR 1 // add functionality in a backwards compatible manner
#define ANKERL_UNORDERED_DENSE_VERSION_PATCH 0 // backwards compatible bug fixes
#if defined(_MSVC_LANG)
# define ANKERL_UNORDERED_DENSE_CPP_VERSION _MSVC_LANG
#else
# define ANKERL_UNORDERED_DENSE_CPP_VERSION __cplusplus
#endif
#if defined(__GNUC__)
# define ANKERL_UNORDERED_DENSE_PACK(decl) decl __attribute__((__packed__))
#elif defined(_MSC_VER)
# define ANKERL_UNORDERED_DENSE_PACK(decl) __pragma(pack(push, 1)) decl __pragma(pack(pop))
#endif
#if ANKERL_UNORDERED_DENSE_CPP_VERSION < 201703L
# error ankerl::unordered_dense requires C++17 or higher
#else
# include <array> // for array
# include <cstdint> // for uint64_t, uint32_t, uint8_t, UINT64_C
# include <cstring> // for size_t, memcpy, memset
# include <functional> // for equal_to, hash
# include <initializer_list> // for initializer_list
# include <iterator> // for pair, distance
# include <limits> // for numeric_limits
# include <memory> // for allocator, allocator_traits, shared_ptr
# include <stdexcept> // for out_of_range
# include <string> // for basic_string
# include <string_view> // for basic_string_view, hash
# include <tuple> // for forward_as_tuple
# include <type_traits> // for enable_if_t, declval, conditional_t, ena...
# include <utility> // for forward, exchange, pair, as_const, piece...
# include <vector> // for vector
# define ANKERL_UNORDERED_DENSE_PMR 0
# if defined(__has_include)
# if __has_include(<memory_resource>)
# undef ANKERL_UNORDERED_DENSE_PMR
# define ANKERL_UNORDERED_DENSE_PMR 1
# include <memory_resource> // for polymorphic_allocator
# endif
# endif
# if defined(_MSC_VER) && defined(_M_X64)
# include <intrin.h>
# pragma intrinsic(_umul128)
# endif
# if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
# define ANKERL_UNORDERED_DENSE_LIKELY(x) __builtin_expect(x, 1)
# define ANKERL_UNORDERED_DENSE_UNLIKELY(x) __builtin_expect(x, 0)
# else
# define ANKERL_UNORDERED_DENSE_LIKELY(x) (x)
# define ANKERL_UNORDERED_DENSE_UNLIKELY(x) (x)
# endif
namespace ankerl::unordered_dense {
// hash ///////////////////////////////////////////////////////////////////////
// This is a stripped-down implementation of wyhash: https://github.com/wangyi-fudan/wyhash
// No big-endian support (because different values on different machines don't matter),
// hardcodes seed and the secret, reformattes the code, and clang-tidy fixes.
namespace detail::wyhash {
static inline void mum(uint64_t* a, uint64_t* b) {
# if defined(__SIZEOF_INT128__)
__uint128_t r = *a;
r *= *b;
*a = static_cast<uint64_t>(r);
*b = static_cast<uint64_t>(r >> 64U);
# elif defined(_MSC_VER) && defined(_M_X64)
*a = _umul128(*a, *b, b);
# else
uint64_t ha = *a >> 32U;
uint64_t hb = *b >> 32U;
uint64_t la = static_cast<uint32_t>(*a);
uint64_t lb = static_cast<uint32_t>(*b);
uint64_t hi{};
uint64_t lo{};
uint64_t rh = ha * hb;
uint64_t rm0 = ha * lb;
uint64_t rm1 = hb * la;
uint64_t rl = la * lb;
uint64_t t = rl + (rm0 << 32U);
auto c = static_cast<uint64_t>(t < rl);
lo = t + (rm1 << 32U);
c += static_cast<uint64_t>(lo < t);
hi = rh + (rm0 >> 32U) + (rm1 >> 32U) + c;
*a = lo;
*b = hi;
# endif
}
// multiply and xor mix function, aka MUM
[[nodiscard]] static inline auto mix(uint64_t a, uint64_t b) -> uint64_t {
mum(&a, &b);
return a ^ b;
}
// read functions. WARNING: we don't care about endianness, so results are different on big endian!
[[nodiscard]] static inline auto r8(const uint8_t* p) -> uint64_t {
uint64_t v{};
std::memcpy(&v, p, 8);
return v;
}
[[nodiscard]] static inline auto r4(const uint8_t* p) -> uint64_t {
uint32_t v{};
std::memcpy(&v, p, 4);
return v;
}
// reads 1, 2, or 3 bytes
[[nodiscard]] static inline auto r3(const uint8_t* p, size_t k) -> uint64_t {
return (static_cast<uint64_t>(p[0]) << 16U) | (static_cast<uint64_t>(p[k >> 1U]) << 8U) | p[k - 1];
}
[[nodiscard]] static inline auto hash(void const* key, size_t len) -> uint64_t {
static constexpr auto secret = std::array{UINT64_C(0xa0761d6478bd642f),
UINT64_C(0xe7037ed1a0b428db),
UINT64_C(0x8ebc6af09c88c6e3),
UINT64_C(0x589965cc75374cc3)};
auto const* p = static_cast<uint8_t const*>(key);
uint64_t seed = secret[0];
uint64_t a{};
uint64_t b{};
if (ANKERL_UNORDERED_DENSE_LIKELY(len <= 16)) {
if (ANKERL_UNORDERED_DENSE_LIKELY(len >= 4)) {
a = (r4(p) << 32U) | r4(p + ((len >> 3U) << 2U));
b = (r4(p + len - 4) << 32U) | r4(p + len - 4 - ((len >> 3U) << 2U));
} else if (ANKERL_UNORDERED_DENSE_LIKELY(len > 0)) {
a = r3(p, len);
b = 0;
} else {
a = 0;
b = 0;
}
} else {
size_t i = len;
if (ANKERL_UNORDERED_DENSE_UNLIKELY(i > 48)) {
uint64_t see1 = seed;
uint64_t see2 = seed;
do {
seed = mix(r8(p) ^ secret[1], r8(p + 8) ^ seed);
see1 = mix(r8(p + 16) ^ secret[2], r8(p + 24) ^ see1);
see2 = mix(r8(p + 32) ^ secret[3], r8(p + 40) ^ see2);
p += 48;
i -= 48;
} while (ANKERL_UNORDERED_DENSE_LIKELY(i > 48));
seed ^= see1 ^ see2;
}
while (ANKERL_UNORDERED_DENSE_UNLIKELY(i > 16)) {
seed = mix(r8(p) ^ secret[1], r8(p + 8) ^ seed);
i -= 16;
p += 16;
}
a = r8(p + i - 16);
b = r8(p + i - 8);
}
return mix(secret[1] ^ len, mix(a ^ secret[1], b ^ seed));
}
[[nodiscard]] static inline auto hash(uint64_t x) -> uint64_t {
return detail::wyhash::mix(x, UINT64_C(0x9E3779B97F4A7C15));
}
} // namespace detail::wyhash
template <typename T, typename Enable = void>
struct hash : public std::hash<T> {
using is_avalanching = void;
auto operator()(T const& obj) const noexcept(noexcept(std::declval<std::hash<T>>().operator()(std::declval<T const&>())))
-> size_t {
return static_cast<size_t>(detail::wyhash::hash(std::hash<T>::operator()(obj)));
}
};
template <typename CharT>
struct hash<std::basic_string<CharT>> {
using is_avalanching = void;
auto operator()(std::basic_string<CharT> const& str) const noexcept -> size_t {
return static_cast<size_t>(detail::wyhash::hash(str.data(), sizeof(CharT) * str.size()));
}
};
template <typename CharT>
struct hash<std::basic_string_view<CharT>> {
using is_avalanching = void;
auto operator()(std::basic_string_view<CharT> const& sv) const noexcept -> size_t {
return static_cast<size_t>(detail::wyhash::hash(sv.data(), sizeof(CharT) * sv.size()));
}
};
template <class T>
struct hash<T*> {
using is_avalanching = void;
auto operator()(T* ptr) const noexcept -> size_t {
return static_cast<size_t>(detail::wyhash::hash(reinterpret_cast<uintptr_t>(ptr)));
}
};
template <class T>
struct hash<std::unique_ptr<T>> {
using is_avalanching = void;
auto operator()(std::unique_ptr<T> const& ptr) const noexcept -> size_t {
return static_cast<size_t>(detail::wyhash::hash(reinterpret_cast<uintptr_t>(ptr.get())));
}
};
template <class T>
struct hash<std::shared_ptr<T>> {
using is_avalanching = void;
auto operator()(std::shared_ptr<T> const& ptr) const noexcept -> size_t {
return static_cast<size_t>(detail::wyhash::hash(reinterpret_cast<uintptr_t>(ptr.get())));
}
};
template <typename Enum>
struct hash<Enum, typename std::enable_if<std::is_enum<Enum>::value>::type> {
using is_avalanching = void;
auto operator()(Enum e) const noexcept -> size_t {
using Underlying = typename std::underlying_type_t<Enum>;
return static_cast<size_t>(detail::wyhash::hash(static_cast<Underlying>(e)));
}
};
# define ANKERL_UNORDERED_DENSE_HASH_STATICCAST(T) \
template <> \
struct hash<T> { \
using is_avalanching = void; \
auto operator()(T const& obj) const noexcept -> size_t { \
return static_cast<size_t>(detail::wyhash::hash(static_cast<uint64_t>(obj))); \
} \
}
# if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wuseless-cast"
# endif
// see https://en.cppreference.com/w/cpp/utility/hash
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(bool);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(char);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(signed char);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(unsigned char);
# if ANKERL_UNORDERED_DENSE_CPP_VERSION >= 202002L
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(char8_t);
# endif
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(char16_t);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(char32_t);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(wchar_t);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(short);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(unsigned short);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(int);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(unsigned int);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(long);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(long long);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(unsigned long);
ANKERL_UNORDERED_DENSE_HASH_STATICCAST(unsigned long long);
# if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic pop
# endif
// bucket_type //////////////////////////////////////////////////////////
namespace bucket_type {
struct standard {
static constexpr uint32_t DIST_INC = 1U << 8U; // skip 1 byte fingerprint
static constexpr uint32_t FINGERPRINT_MASK = DIST_INC - 1; // mask for 1 byte of fingerprint
uint32_t dist_and_fingerprint; // upper 3 byte: distance to original bucket. lower byte: fingerprint from hash
uint32_t value_idx; // index into the m_values vector.
};
ANKERL_UNORDERED_DENSE_PACK(struct big {
static constexpr uint32_t DIST_INC = 1U << 8U; // skip 1 byte fingerprint
static constexpr uint32_t FINGERPRINT_MASK = DIST_INC - 1; // mask for 1 byte of fingerprint
uint32_t dist_and_fingerprint; // upper 3 byte: distance to original bucket. lower byte: fingerprint from hash
size_t value_idx; // index into the m_values vector.
});
} // namespace bucket_type
namespace detail {
struct nonesuch {};
template <class Default, class AlwaysVoid, template <class...> class Op, class... Args>
struct detector {
using value_t = std::false_type;
using type = Default;
};
template <class Default, template <class...> class Op, class... Args>
struct detector<Default, std::void_t<Op<Args...>>, Op, Args...> {
using value_t = std::true_type;
using type = Op<Args...>;
};
template <template <class...> class Op, class... Args>
using is_detected = typename detail::detector<detail::nonesuch, void, Op, Args...>::value_t;
template <template <class...> class Op, class... Args>
constexpr bool is_detected_v = is_detected<Op, Args...>::value;
template <typename T>
using detect_avalanching = typename T::is_avalanching;
template <typename T>
using detect_is_transparent = typename T::is_transparent;
template <typename H, typename KE>
using is_transparent =
std::enable_if_t<is_detected_v<detect_is_transparent, H> && is_detected_v<detect_is_transparent, KE>, bool>;
// This is it, the table. Doubles as map and set, and uses `void` for T when its used as a set.
template <class Key,
class T, // when void, treat it as a set.
class Hash,
class KeyEqual,
class Allocator,
class Bucket>
class table {
using ValueContainer =
typename std::vector<typename std::conditional_t<std::is_void_v<T>, Key, std::pair<Key, T>>, Allocator>;
using BucketAlloc = typename std::allocator_traits<Allocator>::template rebind_alloc<Bucket>;
using BucketAllocTraits = std::allocator_traits<BucketAlloc>;
static constexpr uint8_t INITIAL_SHIFTS = 64 - 3; // 2^(64-m_shift) number of buckets
static constexpr float DEFAULT_MAX_LOAD_FACTOR = 0.8F;
public:
using key_type = Key;
using mapped_type = T;
using value_container_type = ValueContainer;
using value_type = typename value_container_type::value_type;
using size_type = typename value_container_type::size_type;
using difference_type = typename value_container_type::difference_type;
using hasher = Hash;
using key_equal = KeyEqual;
using allocator_type = typename value_container_type::allocator_type;
using reference = typename value_container_type::reference;
using const_reference = typename value_container_type::const_reference;
using pointer = typename value_container_type::pointer;
using const_pointer = typename value_container_type::const_pointer;
using iterator = typename value_container_type::iterator;
using const_iterator = typename value_container_type::const_iterator;
using bucket_type = Bucket;
private:
using value_idx_type = decltype(Bucket::value_idx);
using dist_and_fingerprint_type = decltype(Bucket::dist_and_fingerprint);
static_assert(std::is_trivially_destructible_v<Bucket>, "assert there's no need to call destructor / std::destroy");
static_assert(std::is_trivially_copyable_v<Bucket>, "assert we can just memset / memcpy");
value_container_type m_values{}; // Contains all the key-value pairs in one densely stored container. No holes.
Bucket* m_buckets = nullptr;
size_t m_num_buckets = 0;
value_idx_type m_max_bucket_capacity = 0;
float m_max_load_factor = DEFAULT_MAX_LOAD_FACTOR;
Hash m_hash{};
KeyEqual m_equal{};
uint8_t m_shifts = INITIAL_SHIFTS;
[[nodiscard]] auto next(size_t bucket_idx) const -> size_t {
return ANKERL_UNORDERED_DENSE_UNLIKELY(bucket_idx + 1 == m_num_buckets) ? 0 : bucket_idx + 1;
}
template <typename K>
[[nodiscard]] constexpr auto mixed_hash(K const& key) const -> uint64_t {
if constexpr (is_detected_v<detect_avalanching, Hash>) {
return m_hash(key);
} else {
return wyhash::hash(m_hash(key));
}
}
[[nodiscard]] constexpr auto dist_and_fingerprint_from_hash(uint64_t hash) const -> dist_and_fingerprint_type {
return Bucket::DIST_INC | (static_cast<dist_and_fingerprint_type>(hash) & Bucket::FINGERPRINT_MASK);
}
[[nodiscard]] constexpr auto bucket_idx_from_hash(uint64_t hash) const -> size_t {
return static_cast<size_t>(hash >> m_shifts);
}
[[nodiscard]] static constexpr auto get_key(value_type const& vt) -> key_type const& {
if constexpr (std::is_void_v<T>) {
return vt;
} else {
return vt.first;
}
}
template <typename K>
[[nodiscard]] auto next_while_less(K const& key) const -> std::pair<dist_and_fingerprint_type, size_t> {
auto hash = mixed_hash(key);
auto dist_and_fingerprint = dist_and_fingerprint_from_hash(hash);
auto bucket_idx = bucket_idx_from_hash(hash);
while (dist_and_fingerprint < m_buckets[bucket_idx].dist_and_fingerprint) {
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
}
return {dist_and_fingerprint, bucket_idx};
}
void place_and_shift_up(Bucket bucket, size_t place) {
while (0 != m_buckets[place].dist_and_fingerprint) {
bucket = std::exchange(m_buckets[place], bucket);
bucket.dist_and_fingerprint += Bucket::DIST_INC;
place = next(place);
}
m_buckets[place] = bucket;
}
[[nodiscard]] static constexpr auto calc_num_buckets(uint8_t shifts) -> size_t {
return size_t{1} << (64U - shifts);
}
[[nodiscard]] constexpr auto calc_shifts_for_size(size_t s) const -> uint8_t {
auto shifts = INITIAL_SHIFTS;
while (shifts > 0 && static_cast<size_t>(static_cast<float>(calc_num_buckets(shifts)) * max_load_factor()) < s) {
--shifts;
}
return shifts;
}
// assumes m_values has data, m_buckets=m_buckets_end=nullptr, m_shifts is INITIAL_SHIFTS
void copy_buckets(table const& other) {
if (!empty()) {
m_shifts = other.m_shifts;
allocate_buckets_from_shift();
std::memcpy(m_buckets, other.m_buckets, sizeof(Bucket) * bucket_count());
}
}
/**
* True when no element can be added any more without increasing the size
*/
[[nodiscard]] auto is_full() const -> bool {
return size() >= m_max_bucket_capacity;
}
void deallocate_buckets() {
auto bucket_alloc = BucketAlloc(m_values.get_allocator());
BucketAllocTraits::deallocate(bucket_alloc, m_buckets, bucket_count());
m_buckets = nullptr;
m_num_buckets = 0;
m_max_bucket_capacity = 0;
}
void allocate_buckets_from_shift() {
auto bucket_alloc = BucketAlloc(m_values.get_allocator());
m_num_buckets = calc_num_buckets(m_shifts);
m_buckets = BucketAllocTraits::allocate(bucket_alloc, m_num_buckets);
m_max_bucket_capacity = static_cast<value_idx_type>(static_cast<float>(m_num_buckets) * max_load_factor());
}
void clear_buckets() {
if (m_buckets != nullptr) {
std::memset(m_buckets, 0, sizeof(Bucket) * bucket_count());
}
}
void clear_and_fill_buckets_from_values() {
clear_buckets();
for (value_idx_type value_idx = 0, end_idx = static_cast<value_idx_type>(m_values.size()); value_idx < end_idx;
++value_idx) {
auto const& key = get_key(m_values[value_idx]);
auto [dist_and_fingerprint, bucket] = next_while_less(key);
// we know for certain that key has not yet been inserted, so no need to check it.
place_and_shift_up({dist_and_fingerprint, value_idx}, bucket);
}
}
void increase_size() {
--m_shifts;
deallocate_buckets();
allocate_buckets_from_shift();
clear_and_fill_buckets_from_values();
}
void do_erase(size_t bucket_idx) {
auto const value_idx_to_remove = m_buckets[bucket_idx].value_idx;
// shift down until either empty or an element with correct spot is found
auto next_bucket_idx = next(bucket_idx);
while (m_buckets[next_bucket_idx].dist_and_fingerprint >= Bucket::DIST_INC * 2) {
m_buckets[bucket_idx] = {m_buckets[next_bucket_idx].dist_and_fingerprint - Bucket::DIST_INC,
m_buckets[next_bucket_idx].value_idx};
bucket_idx = std::exchange(next_bucket_idx, next(next_bucket_idx));
}
m_buckets[bucket_idx] = {};
// update m_values
if (value_idx_to_remove != m_values.size() - 1) {
// no luck, we'll have to replace the value with the last one and update the index accordingly
auto& val = m_values[value_idx_to_remove];
val = std::move(m_values.back());
// update the values_idx of the moved entry. No need to play the info game, just look until we find the values_idx
auto mh = mixed_hash(get_key(val));
bucket_idx = bucket_idx_from_hash(mh);
auto const values_idx_back = static_cast<value_idx_type>(m_values.size() - 1);
while (values_idx_back != m_buckets[bucket_idx].value_idx) {
bucket_idx = next(bucket_idx);
}
m_buckets[bucket_idx].value_idx = value_idx_to_remove;
}
m_values.pop_back();
}
template <typename K>
auto do_erase_key(K&& key) -> size_t {
if (empty()) {
return 0;
}
auto [dist_and_fingerprint, bucket_idx] = next_while_less(key);
while (dist_and_fingerprint == m_buckets[bucket_idx].dist_and_fingerprint &&
!m_equal(key, get_key(m_values[m_buckets[bucket_idx].value_idx]))) {
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
}
if (dist_and_fingerprint != m_buckets[bucket_idx].dist_and_fingerprint) {
return 0;
}
do_erase(bucket_idx);
return 1;
}
template <class K, class M>
auto do_insert_or_assign(K&& key, M&& mapped) -> std::pair<iterator, bool> {
auto it_isinserted = try_emplace(std::forward<K>(key), std::forward<M>(mapped));
if (!it_isinserted.second) {
it_isinserted.first->second = std::forward<M>(mapped);
}
return it_isinserted;
}
template <typename K, typename... Args>
auto do_place_element(dist_and_fingerprint_type dist_and_fingerprint, size_t bucket_idx, K&& key, Args&&... args)
-> std::pair<iterator, bool> {
// emplace the new value. If that throws an exception, no harm done; index is still in a valid state
m_values.emplace_back(std::piecewise_construct,
std::forward_as_tuple(std::forward<K>(key)),
std::forward_as_tuple(std::forward<Args>(args)...));
// place element and shift up until we find an empty spot
auto value_idx = static_cast<value_idx_type>(m_values.size()) - 1;
place_and_shift_up({dist_and_fingerprint, value_idx}, bucket_idx);
return {begin() + static_cast<difference_type>(value_idx), true};
}
template <typename K, typename... Args>
auto do_try_emplace(K&& key, Args&&... args) -> std::pair<iterator, bool> {
if (ANKERL_UNORDERED_DENSE_UNLIKELY(is_full())) {
increase_size();
}
auto hash = mixed_hash(key);
auto dist_and_fingerprint = dist_and_fingerprint_from_hash(hash);
auto bucket_idx = bucket_idx_from_hash(hash);
while (true) {
auto* bucket = m_buckets + bucket_idx;
if (dist_and_fingerprint == bucket->dist_and_fingerprint) {
if (m_equal(key, m_values[bucket->value_idx].first)) {
return {begin() + static_cast<difference_type>(bucket->value_idx), false};
}
} else if (dist_and_fingerprint > bucket->dist_and_fingerprint) {
return do_place_element(dist_and_fingerprint, bucket_idx, std::forward<K>(key), std::forward<Args>(args)...);
}
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
}
}
template <typename K>
auto do_find(K const& key) -> iterator {
if (ANKERL_UNORDERED_DENSE_UNLIKELY(empty())) {
return end();
}
auto mh = mixed_hash(key);
auto dist_and_fingerprint = dist_and_fingerprint_from_hash(mh);
auto bucket_idx = bucket_idx_from_hash(mh);
auto* bucket = m_buckets + bucket_idx;
// unrolled loop. *Always* check a few directly, then enter the loop. This is faster.
if (dist_and_fingerprint == bucket->dist_and_fingerprint && m_equal(key, get_key(m_values[bucket->value_idx]))) {
return begin() + static_cast<difference_type>(bucket->value_idx);
}
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
bucket = m_buckets + bucket_idx;
if (dist_and_fingerprint == bucket->dist_and_fingerprint && m_equal(key, get_key(m_values[bucket->value_idx]))) {
return begin() + static_cast<difference_type>(bucket->value_idx);
}
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
bucket = m_buckets + bucket_idx;
while (true) {
if (dist_and_fingerprint == bucket->dist_and_fingerprint) {
if (m_equal(key, get_key(m_values[bucket->value_idx]))) {
return begin() + static_cast<difference_type>(bucket->value_idx);
}
} else if (dist_and_fingerprint > bucket->dist_and_fingerprint) {
return end();
}
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
bucket = m_buckets + bucket_idx;
}
}
template <typename K>
auto do_find(K const& key) const -> const_iterator {
return const_cast<table*>(this)->do_find(key); // NOLINT(cppcoreguidelines-pro-type-const-cast)
}
public:
table()
: table(0) {}
explicit table(size_t /*bucket_count*/,
Hash const& hash = Hash(),
KeyEqual const& equal = KeyEqual(),
Allocator const& alloc = Allocator())
: m_values(alloc)
, m_hash(hash)
, m_equal(equal) {}
table(size_t bucket_count, Allocator const& alloc)
: table(bucket_count, Hash(), KeyEqual(), alloc) {}
table(size_t bucket_count, Hash const& hash, Allocator const& alloc)
: table(bucket_count, hash, KeyEqual(), alloc) {}
explicit table(Allocator const& alloc)
: table(0, Hash(), KeyEqual(), alloc) {}
template <class InputIt>
table(InputIt first,
InputIt last,
size_type bucket_count = 0,
Hash const& hash = Hash(),
KeyEqual const& equal = KeyEqual(),
Allocator const& alloc = Allocator())
: table(bucket_count, hash, equal, alloc) {
insert(first, last);
}
template <class InputIt>
table(InputIt first, InputIt last, size_type bucket_count, Allocator const& alloc)
: table(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
template <class InputIt>
table(InputIt first, InputIt last, size_type bucket_count, Hash const& hash, Allocator const& alloc)
: table(first, last, bucket_count, hash, KeyEqual(), alloc) {}
table(table const& other)
: table(other, other.m_values.get_allocator()) {}
table(table const& other, Allocator const& alloc)
: m_values(other.m_values, alloc)
, m_max_load_factor(other.m_max_load_factor)
, m_hash(other.m_hash)
, m_equal(other.m_equal) {
copy_buckets(other);
}
table(table&& other) noexcept
: table(std::move(other), other.m_values.get_allocator()) {}
table(table&& other, Allocator const& alloc) noexcept
: m_values(std::move(other.m_values), alloc)
, m_buckets(std::exchange(other.m_buckets, nullptr))
, m_num_buckets(std::exchange(other.m_num_buckets, 0))
, m_max_bucket_capacity(std::exchange(other.m_max_bucket_capacity, 0))
, m_max_load_factor(std::exchange(other.m_max_load_factor, DEFAULT_MAX_LOAD_FACTOR))
, m_hash(std::exchange(other.m_hash, {}))
, m_equal(std::exchange(other.m_equal, {}))
, m_shifts(std::exchange(other.m_shifts, INITIAL_SHIFTS)) {
other.m_values.clear();
}
table(std::initializer_list<value_type> ilist,
size_t bucket_count = 0,
Hash const& hash = Hash(),
KeyEqual const& equal = KeyEqual(),
Allocator const& alloc = Allocator())
: table(bucket_count, hash, equal, alloc) {
insert(ilist);
}
table(std::initializer_list<value_type> ilist, size_type bucket_count, const Allocator& alloc)
: table(ilist, bucket_count, Hash(), KeyEqual(), alloc) {}
table(std::initializer_list<value_type> init, size_type bucket_count, Hash const& hash, Allocator const& alloc)
: table(init, bucket_count, hash, KeyEqual(), alloc) {}
~table() {
auto bucket_alloc = BucketAlloc(m_values.get_allocator());
BucketAllocTraits::deallocate(bucket_alloc, m_buckets, bucket_count());
}
auto operator=(table const& other) -> table& {
if (&other != this) {
deallocate_buckets(); // deallocate before m_values is set (might have another allocator)
m_values = other.m_values;
m_max_load_factor = other.m_max_load_factor;
m_hash = other.m_hash;
m_equal = other.m_equal;
m_shifts = INITIAL_SHIFTS;
copy_buckets(other);
}
return *this;
}
auto operator=(table&& other) noexcept(
noexcept(std::is_nothrow_move_assignable_v<value_container_type>&& std::is_nothrow_move_assignable_v<Hash>&&
std::is_nothrow_move_assignable_v<KeyEqual>)) -> table& {
if (&other != this) {
deallocate_buckets(); // deallocate before m_values is set (might have another allocator)
m_values = std::move(other.m_values);
m_buckets = std::exchange(other.m_buckets, nullptr);
m_num_buckets = std::exchange(other.m_num_buckets, 0);
m_max_bucket_capacity = std::exchange(other.m_max_bucket_capacity, 0);
m_max_load_factor = std::exchange(other.m_max_load_factor, DEFAULT_MAX_LOAD_FACTOR);
m_hash = std::exchange(other.m_hash, {});
m_equal = std::exchange(other.m_equal, {});
m_shifts = std::exchange(other.m_shifts, INITIAL_SHIFTS);
other.m_values.clear();
}
return *this;
}
auto operator=(std::initializer_list<value_type> ilist) -> table& {
clear();
insert(ilist);
return *this;
}
auto get_allocator() const noexcept -> allocator_type {
return m_values.get_allocator();
}
// iterators //////////////////////////////////////////////////////////////
auto begin() noexcept -> iterator {
return m_values.begin();
}
auto begin() const noexcept -> const_iterator {
return m_values.begin();
}
auto cbegin() const noexcept -> const_iterator {
return m_values.cbegin();
}
auto end() noexcept -> iterator {
return m_values.end();
}
auto cend() const noexcept -> const_iterator {
return m_values.cend();
}
auto end() const noexcept -> const_iterator {
return m_values.end();
}
// capacity ///////////////////////////////////////////////////////////////
[[nodiscard]] auto empty() const noexcept -> bool {
return m_values.empty();
}
[[nodiscard]] auto size() const noexcept -> size_t {
return m_values.size();
}
[[nodiscard]] static constexpr auto max_size() noexcept -> size_t {
return std::numeric_limits<value_idx_type>::max();
}
// modifiers //////////////////////////////////////////////////////////////
void clear() {
m_values.clear();
clear_buckets();
}
auto insert(value_type const& value) -> std::pair<iterator, bool> {
return emplace(value);
}
auto insert(value_type&& value) -> std::pair<iterator, bool> {
return emplace(std::move(value));
}
template <class P, std::enable_if_t<std::is_constructible_v<value_type, P&&>, bool> = true>
auto insert(P&& value) -> std::pair<iterator, bool> {
return emplace(std::forward<P>(value));
}
auto insert(const_iterator /*hint*/, value_type const& value) -> iterator {
return insert(value).first;
}
auto insert(const_iterator /*hint*/, value_type&& value) -> iterator {
return insert(std::move(value)).first;
}
template <class P, std::enable_if_t<std::is_constructible_v<value_type, P&&>, bool> = true>
auto insert(const_iterator /*hint*/, P&& value) -> iterator {
return insert(std::forward<P>(value)).first;
}
template <class InputIt>
void insert(InputIt first, InputIt last) {
while (first != last) {
insert(*first);
++first;
}
}
void insert(std::initializer_list<value_type> ilist) {
insert(ilist.begin(), ilist.end());
}
// nonstandard API: *this is emptied.
// Also see "A Standard flat_map" https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p0429r9.pdf
auto extract() && -> value_container_type {
return std::move(m_values);
}
template <class M, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto insert_or_assign(Key const& key, M&& mapped) -> std::pair<iterator, bool> {
return do_insert_or_assign(key, std::forward<M>(mapped));
}
template <class M, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto insert_or_assign(Key&& key, M&& mapped) -> std::pair<iterator, bool> {
return do_insert_or_assign(std::move(key), std::forward<M>(mapped));
}
template <class M, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto insert_or_assign(const_iterator /*hint*/, Key const& key, M&& mapped) -> iterator {
return do_insert_or_assign(key, std::forward<M>(mapped)).first;
}
template <class M, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto insert_or_assign(const_iterator /*hint*/, Key&& key, M&& mapped) -> iterator {
return do_insert_or_assign(std::move(key), std::forward<M>(mapped)).first;
}
template <class... Args>
auto emplace(Args&&... args) -> std::pair<iterator, bool> {
if (is_full()) {
increase_size();
}
// first emplace_back the object so it is constructed. If the key is already there, pop it.
auto& val = m_values.emplace_back(std::forward<Args>(args)...);
auto hash = mixed_hash(get_key(val));
auto dist_and_fingerprint = dist_and_fingerprint_from_hash(hash);
auto bucket_idx = bucket_idx_from_hash(hash);
while (dist_and_fingerprint <= m_buckets[bucket_idx].dist_and_fingerprint) {
if (dist_and_fingerprint == m_buckets[bucket_idx].dist_and_fingerprint &&
m_equal(get_key(val), get_key(m_values[m_buckets[bucket_idx].value_idx]))) {
m_values.pop_back(); // value was already there, so get rid of it
return {begin() + static_cast<difference_type>(m_buckets[bucket_idx].value_idx), false};
}
dist_and_fingerprint += Bucket::DIST_INC;
bucket_idx = next(bucket_idx);
}
// value is new, place the bucket and shift up until we find an empty spot
value_idx_type value_idx = static_cast<value_idx_type>(m_values.size()) - 1;
place_and_shift_up({dist_and_fingerprint, value_idx}, bucket_idx);
return {begin() + static_cast<difference_type>(value_idx), true};
}
template <class... Args>
auto emplace_hint(const_iterator /*hint*/, Args&&... args) -> iterator {
return emplace(std::forward<Args>(args)...).first;
}
template <class... Args, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto try_emplace(Key const& key, Args&&... args) -> std::pair<iterator, bool> {
return do_try_emplace(key, std::forward<Args>(args)...);
}
template <class... Args, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto try_emplace(Key&& key, Args&&... args) -> std::pair<iterator, bool> {
return do_try_emplace(std::move(key), std::forward<Args>(args)...);
}
template <class... Args, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto try_emplace(const_iterator /*hint*/, Key const& key, Args&&... args) -> iterator {
return do_try_emplace(key, std::forward<Args>(args)...).first;
}
template <class... Args, typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto try_emplace(const_iterator /*hint*/, Key&& key, Args&&... args) -> iterator {
return do_try_emplace(std::move(key), std::forward<Args>(args)...).first;
}
auto erase(iterator it) -> iterator {
auto hash = mixed_hash(get_key(*it));
auto bucket_idx = bucket_idx_from_hash(hash);
auto const value_idx_to_remove = static_cast<value_idx_type>(it - cbegin());
while (m_buckets[bucket_idx].value_idx != value_idx_to_remove) {
bucket_idx = next(bucket_idx);
}
do_erase(bucket_idx);
return begin() + static_cast<difference_type>(value_idx_to_remove);
}
auto erase(const_iterator it) -> iterator {
return erase(begin() + (it - cbegin()));
}
auto erase(const_iterator first, const_iterator last) -> iterator {
auto const idx_first = first - cbegin();
auto const idx_last = last - cbegin();
auto const first_to_last = std::distance(first, last);
auto const last_to_end = std::distance(last, cend());
// remove elements from left to right which moves elements from the end back
auto const mid = idx_first + std::min(first_to_last, last_to_end);
auto idx = idx_first;
while (idx != mid) {
erase(begin() + idx);
++idx;
}
// all elements from the right are moved, now remove the last element until all done
idx = idx_last;
while (idx != mid) {
--idx;
erase(begin() + idx);
}
return begin() + idx_first;
}
auto erase(Key const& key) -> size_t {
return do_erase_key(key);
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto erase(K&& key) -> size_t {
return do_erase_key(std::forward<K>(key));
}
void swap(table& other) noexcept(noexcept(std::is_nothrow_swappable_v<value_container_type>&&
std::is_nothrow_swappable_v<Hash>&& std::is_nothrow_swappable_v<KeyEqual>)) {
using std::swap;
swap(other, *this);
}
// lookup /////////////////////////////////////////////////////////////////
template <typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto at(key_type const& key) -> Q& {
if (auto it = find(key); end() != it) {
return it->second;
}
throw std::out_of_range("ankerl::unordered_dense::map::at(): key not found");
} // LCOV_EXCL_LINE is this a gcov/lcov bug? this method is fully tested.
template <typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto at(key_type const& key) const -> Q const& {
return const_cast<table*>(this)->at(key); // NOLINT(cppcoreguidelines-pro-type-const-cast)
}
template <typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto operator[](Key const& key) -> Q& {
return try_emplace(key).first->second;
}
template <typename Q = T, std::enable_if_t<!std::is_void_v<Q>, bool> = true>
auto operator[](Key&& key) -> Q& {
return try_emplace(std::move(key)).first->second;
}
auto count(Key const& key) const -> size_t {
return find(key) == end() ? 0 : 1;
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto count(K const& key) const -> size_t {
return find(key) == end() ? 0 : 1;
}
auto find(Key const& key) -> iterator {
return do_find(key);
}
auto find(Key const& key) const -> const_iterator {
return do_find(key);
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto find(K const& key) -> iterator {
return do_find(key);
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto find(K const& key) const -> const_iterator {
return do_find(key);
}
auto contains(Key const& key) const -> size_t {
return find(key) != end();
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto contains(K const& key) const -> size_t {
return find(key) != end();
}
auto equal_range(Key const& key) -> std::pair<iterator, iterator> {
auto it = do_find(key);
return {it, it == end() ? end() : it + 1};
}
auto equal_range(const Key& key) const -> std::pair<const_iterator, const_iterator> {
auto it = do_find(key);
return {it, it == end() ? end() : it + 1};
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto equal_range(K const& key) -> std::pair<iterator, iterator> {
auto it = do_find(key);
return {it, it == end() ? end() : it + 1};
}
template <class K, class H = Hash, class KE = KeyEqual, is_transparent<H, KE> = true>
auto equal_range(K const& key) const -> std::pair<const_iterator, const_iterator> {
auto it = do_find(key);
return {it, it == end() ? end() : it + 1};
}
// bucket interface ///////////////////////////////////////////////////////
auto bucket_count() const noexcept -> size_t { // NOLINT(modernize-use-nodiscard)
return m_num_buckets;
}
static constexpr auto max_bucket_count() noexcept -> size_t { // NOLINT(modernize-use-nodiscard)
return std::numeric_limits<value_idx_type>::max();
}
// hash policy ////////////////////////////////////////////////////////////
[[nodiscard]] auto load_factor() const -> float {
return bucket_count() ? static_cast<float>(size()) / static_cast<float>(bucket_count()) : 0.0F;
}
[[nodiscard]] auto max_load_factor() const -> float {
return m_max_load_factor;
}
void max_load_factor(float ml) {
m_max_load_factor = ml;
m_max_bucket_capacity = static_cast<value_idx_type>(static_cast<float>(bucket_count()) * max_load_factor());
}
void rehash(size_t count) {
auto shifts = calc_shifts_for_size(std::max(count, size()));
if (shifts != m_shifts) {
m_shifts = shifts;
deallocate_buckets();
m_values.shrink_to_fit();
allocate_buckets_from_shift();
clear_and_fill_buckets_from_values();
}
}
void reserve(size_t capa) {
m_values.reserve(capa);
auto shifts = calc_shifts_for_size(std::max(capa, size()));
if (shifts < m_shifts) {
m_shifts = shifts;
deallocate_buckets();
allocate_buckets_from_shift();
clear_and_fill_buckets_from_values();
}
}
// observers //////////////////////////////////////////////////////////////
auto hash_function() const -> hasher {
return m_hash;
}
auto key_eq() const -> key_equal {
return m_equal;
}
// nonstandard API: expose the underlying values container
[[nodiscard]] auto values() const noexcept -> value_container_type const& {
return m_values;
}
// non-member functions ///////////////////////////////////////////////////
friend auto operator==(table const& a, table const& b) -> bool {
if (&a == &b) {
return true;
}
if (a.size() != b.size()) {
return false;
}
for (auto const& b_entry : b) {
auto it = a.find(get_key(b_entry));
if constexpr (std::is_void_v<T>) {
// set: only check that the key is here
if (a.end() == it) {
return false;
}
} else {
// map: check that key is here, then also check that value is the same
if (a.end() == it || !(b_entry.second == it->second)) {
return false;
}
}
}
return true;
}
friend auto operator!=(table const& a, table const& b) -> bool {
return !(a == b);
}
};
} // namespace detail
template <class Key,
class T,
class Hash = hash<Key>,
class KeyEqual = std::equal_to<Key>,
class Allocator = std::allocator<std::pair<Key, T>>,
class Bucket = bucket_type::standard>
using map = detail::table<Key, T, Hash, KeyEqual, Allocator, Bucket>;
template <class Key,
class Hash = hash<Key>,
class KeyEqual = std::equal_to<Key>,
class Allocator = std::allocator<Key>,
class Bucket = bucket_type::standard>
using set = detail::table<Key, void, Hash, KeyEqual, Allocator, Bucket>;
# if ANKERL_UNORDERED_DENSE_PMR
namespace pmr {
template <class Key,
class T,
class Hash = hash<Key>,
class KeyEqual = std::equal_to<Key>,
class Bucket = bucket_type::standard>
using map = detail::table<Key, T, Hash, KeyEqual, std::pmr::polymorphic_allocator<std::pair<Key, T>>, Bucket>;
template <class Key, class Hash = hash<Key>, class KeyEqual = std::equal_to<Key>, class Bucket = bucket_type::standard>
using set = detail::table<Key, void, Hash, KeyEqual, std::pmr::polymorphic_allocator<Key>, Bucket>;
} // namespace pmr
# endif
// deduction guides ///////////////////////////////////////////////////////////
// deduction guides for alias templates are only possible since C++20
// see https://en.cppreference.com/w/cpp/language/class_template_argument_deduction
} // namespace ankerl::unordered_dense
// std extensions /////////////////////////////////////////////////////////////
namespace std { // NOLINT(cert-dcl58-cpp)
template <class Key, class T, class Hash, class KeyEqual, class Allocator, class Bucket, class Pred>
auto erase_if(ankerl::unordered_dense::detail::table<Key, T, Hash, KeyEqual, Allocator, Bucket>& map, Pred pred) -> size_t {
using Map = ankerl::unordered_dense::detail::table<Key, T, Hash, KeyEqual, Allocator, Bucket>;
// going back to front because erase() invalidates the end iterator
auto const old_size = map.size();
auto idx = old_size;
while (idx) {
--idx;
auto it = map.begin() + static_cast<typename Map::difference_type>(idx);
if (pred(*it)) {
map.erase(it);
}
}
return map.size() - old_size;
}
} // namespace std
#endif
#endif