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Diffstat (limited to 'src/third-party/robin_hood/robin_hood.h')
| -rw-r--r-- | src/third-party/robin_hood/robin_hood.h | 2544 |
1 files changed, 2544 insertions, 0 deletions
diff --git a/src/third-party/robin_hood/robin_hood.h b/src/third-party/robin_hood/robin_hood.h new file mode 100644 index 0000000..0af031f --- /dev/null +++ b/src/third-party/robin_hood/robin_hood.h @@ -0,0 +1,2544 @@ +// ______ _____ ______ _________ +// ______________ ___ /_ ___(_)_______ ___ /_ ______ ______ ______ / +// __ ___/_ __ \__ __ \__ / __ __ \ __ __ \_ __ \_ __ \_ __ / +// _ / / /_/ /_ /_/ /_ / _ / / / _ / / // /_/ // /_/ // /_/ / +// /_/ \____/ /_.___/ /_/ /_/ /_/ ________/_/ /_/ \____/ \____/ \__,_/ +// _/_____/ +// +// Fast & memory efficient hashtable based on robin hood hashing for C++11/14/17/20 +// https://github.com/martinus/robin-hood-hashing +// +// Licensed under the MIT License <http://opensource.org/licenses/MIT>. +// SPDX-License-Identifier: MIT +// Copyright (c) 2018-2021 Martin Ankerl <http://martin.ankerl.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 ROBIN_HOOD_H_INCLUDED +#define ROBIN_HOOD_H_INCLUDED + +// see https://semver.org/ +#define ROBIN_HOOD_VERSION_MAJOR 3 // for incompatible API changes +#define ROBIN_HOOD_VERSION_MINOR 11 // for adding functionality in a backwards-compatible manner +#define ROBIN_HOOD_VERSION_PATCH 5 // for backwards-compatible bug fixes + +#include <algorithm> +#include <cstdlib> +#include <cstring> +#include <functional> +#include <limits> +#include <memory> // only to support hash of smart pointers +#include <stdexcept> +#include <string> +#include <type_traits> +#include <utility> +#if __cplusplus >= 201703L +# include <string_view> +#endif + +// #define ROBIN_HOOD_LOG_ENABLED +#ifdef ROBIN_HOOD_LOG_ENABLED +# include <iostream> +# define ROBIN_HOOD_LOG(...) \ + std::cout << __FUNCTION__ << "@" << __LINE__ << ": " << __VA_ARGS__ << std::endl; +#else +# define ROBIN_HOOD_LOG(x) +#endif + +// #define ROBIN_HOOD_TRACE_ENABLED +#ifdef ROBIN_HOOD_TRACE_ENABLED +# include <iostream> +# define ROBIN_HOOD_TRACE(...) \ + std::cout << __FUNCTION__ << "@" << __LINE__ << ": " << __VA_ARGS__ << std::endl; +#else +# define ROBIN_HOOD_TRACE(x) +#endif + +// #define ROBIN_HOOD_COUNT_ENABLED +#ifdef ROBIN_HOOD_COUNT_ENABLED +# include <iostream> +# define ROBIN_HOOD_COUNT(x) ++counts().x; +namespace robin_hood { +struct Counts { + uint64_t shiftUp{}; + uint64_t shiftDown{}; +}; +inline std::ostream& operator<<(std::ostream& os, Counts const& c) { + return os << c.shiftUp << " shiftUp" << std::endl << c.shiftDown << " shiftDown" << std::endl; +} + +static Counts& counts() { + static Counts counts{}; + return counts; +} +} // namespace robin_hood +#else +# define ROBIN_HOOD_COUNT(x) +#endif + +// all non-argument macros should use this facility. See +// https://www.fluentcpp.com/2019/05/28/better-macros-better-flags/ +#define ROBIN_HOOD(x) ROBIN_HOOD_PRIVATE_DEFINITION_##x() + +// mark unused members with this macro +#define ROBIN_HOOD_UNUSED(identifier) + +// bitness +#if SIZE_MAX == UINT32_MAX +# define ROBIN_HOOD_PRIVATE_DEFINITION_BITNESS() 32 +#elif SIZE_MAX == UINT64_MAX +# define ROBIN_HOOD_PRIVATE_DEFINITION_BITNESS() 64 +#else +# error Unsupported bitness +#endif + +// endianess +#ifdef _MSC_VER +# define ROBIN_HOOD_PRIVATE_DEFINITION_LITTLE_ENDIAN() 1 +# define ROBIN_HOOD_PRIVATE_DEFINITION_BIG_ENDIAN() 0 +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_LITTLE_ENDIAN() \ + (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) +# define ROBIN_HOOD_PRIVATE_DEFINITION_BIG_ENDIAN() (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) +#endif + +// inline +#ifdef _MSC_VER +# define ROBIN_HOOD_PRIVATE_DEFINITION_NOINLINE() __declspec(noinline) +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_NOINLINE() __attribute__((noinline)) +#endif + +// exceptions +#if !defined(__cpp_exceptions) && !defined(__EXCEPTIONS) && !defined(_CPPUNWIND) +# define ROBIN_HOOD_PRIVATE_DEFINITION_HAS_EXCEPTIONS() 0 +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_HAS_EXCEPTIONS() 1 +#endif + +// count leading/trailing bits +#if !defined(ROBIN_HOOD_DISABLE_INTRINSICS) +# ifdef _MSC_VER +# if ROBIN_HOOD(BITNESS) == 32 +# define ROBIN_HOOD_PRIVATE_DEFINITION_BITSCANFORWARD() _BitScanForward +# else +# define ROBIN_HOOD_PRIVATE_DEFINITION_BITSCANFORWARD() _BitScanForward64 +# endif +# include <intrin.h> +# pragma intrinsic(ROBIN_HOOD(BITSCANFORWARD)) +# define ROBIN_HOOD_COUNT_TRAILING_ZEROES(x) \ + [](size_t mask) noexcept -> int { \ + unsigned long index; \ + return ROBIN_HOOD(BITSCANFORWARD)(&index, mask) ? static_cast<int>(index) \ + : ROBIN_HOOD(BITNESS); \ + }(x) +# else +# if ROBIN_HOOD(BITNESS) == 32 +# define ROBIN_HOOD_PRIVATE_DEFINITION_CTZ() __builtin_ctzl +# define ROBIN_HOOD_PRIVATE_DEFINITION_CLZ() __builtin_clzl +# else +# define ROBIN_HOOD_PRIVATE_DEFINITION_CTZ() __builtin_ctzll +# define ROBIN_HOOD_PRIVATE_DEFINITION_CLZ() __builtin_clzll +# endif +# define ROBIN_HOOD_COUNT_LEADING_ZEROES(x) ((x) ? ROBIN_HOOD(CLZ)(x) : ROBIN_HOOD(BITNESS)) +# define ROBIN_HOOD_COUNT_TRAILING_ZEROES(x) ((x) ? ROBIN_HOOD(CTZ)(x) : ROBIN_HOOD(BITNESS)) +# endif +#endif + +// fallthrough +#ifndef __has_cpp_attribute // For backwards compatibility +# define __has_cpp_attribute(x) 0 +#endif +#if __has_cpp_attribute(clang::fallthrough) +# define ROBIN_HOOD_PRIVATE_DEFINITION_FALLTHROUGH() [[clang::fallthrough]] +#elif __has_cpp_attribute(gnu::fallthrough) +# define ROBIN_HOOD_PRIVATE_DEFINITION_FALLTHROUGH() [[gnu::fallthrough]] +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_FALLTHROUGH() +#endif + +// likely/unlikely +#ifdef _MSC_VER +# define ROBIN_HOOD_LIKELY(condition) condition +# define ROBIN_HOOD_UNLIKELY(condition) condition +#else +# define ROBIN_HOOD_LIKELY(condition) __builtin_expect(condition, 1) +# define ROBIN_HOOD_UNLIKELY(condition) __builtin_expect(condition, 0) +#endif + +// detect if native wchar_t type is availiable in MSVC +#ifdef _MSC_VER +# ifdef _NATIVE_WCHAR_T_DEFINED +# define ROBIN_HOOD_PRIVATE_DEFINITION_HAS_NATIVE_WCHART() 1 +# else +# define ROBIN_HOOD_PRIVATE_DEFINITION_HAS_NATIVE_WCHART() 0 +# endif +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_HAS_NATIVE_WCHART() 1 +#endif + +// detect if MSVC supports the pair(std::piecewise_construct_t,...) consructor being constexpr +#ifdef _MSC_VER +# if _MSC_VER <= 1900 +# define ROBIN_HOOD_PRIVATE_DEFINITION_BROKEN_CONSTEXPR() 1 +# else +# define ROBIN_HOOD_PRIVATE_DEFINITION_BROKEN_CONSTEXPR() 0 +# endif +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_BROKEN_CONSTEXPR() 0 +#endif + +// workaround missing "is_trivially_copyable" in g++ < 5.0 +// See https://stackoverflow.com/a/31798726/48181 +#if defined(__GNUC__) && __GNUC__ < 5 +# define ROBIN_HOOD_IS_TRIVIALLY_COPYABLE(...) __has_trivial_copy(__VA_ARGS__) +#else +# define ROBIN_HOOD_IS_TRIVIALLY_COPYABLE(...) std::is_trivially_copyable<__VA_ARGS__>::value +#endif + +// helpers for C++ versions, see https://gcc.gnu.org/onlinedocs/cpp/Standard-Predefined-Macros.html +#define ROBIN_HOOD_PRIVATE_DEFINITION_CXX() __cplusplus +#define ROBIN_HOOD_PRIVATE_DEFINITION_CXX98() 199711L +#define ROBIN_HOOD_PRIVATE_DEFINITION_CXX11() 201103L +#define ROBIN_HOOD_PRIVATE_DEFINITION_CXX14() 201402L +#define ROBIN_HOOD_PRIVATE_DEFINITION_CXX17() 201703L + +#if ROBIN_HOOD(CXX) >= ROBIN_HOOD(CXX17) +# define ROBIN_HOOD_PRIVATE_DEFINITION_NODISCARD() [[nodiscard]] +#else +# define ROBIN_HOOD_PRIVATE_DEFINITION_NODISCARD() +#endif + +namespace robin_hood { + +#if ROBIN_HOOD(CXX) >= ROBIN_HOOD(CXX14) +# define ROBIN_HOOD_STD std +#else + +// c++11 compatibility layer +namespace ROBIN_HOOD_STD { +template <class T> +struct alignment_of + : std::integral_constant<std::size_t, alignof(typename std::remove_all_extents<T>::type)> {}; + +template <class T, T... Ints> +class integer_sequence { +public: + using value_type = T; + static_assert(std::is_integral<value_type>::value, "not integral type"); + static constexpr std::size_t size() noexcept { + return sizeof...(Ints); + } +}; +template <std::size_t... Inds> +using index_sequence = integer_sequence<std::size_t, Inds...>; + +namespace detail_ { +template <class T, T Begin, T End, bool> +struct IntSeqImpl { + using TValue = T; + static_assert(std::is_integral<TValue>::value, "not integral type"); + static_assert(Begin >= 0 && Begin < End, "unexpected argument (Begin<0 || Begin<=End)"); + + template <class, class> + struct IntSeqCombiner; + + template <TValue... Inds0, TValue... Inds1> + struct IntSeqCombiner<integer_sequence<TValue, Inds0...>, integer_sequence<TValue, Inds1...>> { + using TResult = integer_sequence<TValue, Inds0..., Inds1...>; + }; + + using TResult = + typename IntSeqCombiner<typename IntSeqImpl<TValue, Begin, Begin + (End - Begin) / 2, + (End - Begin) / 2 == 1>::TResult, + typename IntSeqImpl<TValue, Begin + (End - Begin) / 2, End, + (End - Begin + 1) / 2 == 1>::TResult>::TResult; +}; + +template <class T, T Begin> +struct IntSeqImpl<T, Begin, Begin, false> { + using TValue = T; + static_assert(std::is_integral<TValue>::value, "not integral type"); + static_assert(Begin >= 0, "unexpected argument (Begin<0)"); + using TResult = integer_sequence<TValue>; +}; + +template <class T, T Begin, T End> +struct IntSeqImpl<T, Begin, End, true> { + using TValue = T; + static_assert(std::is_integral<TValue>::value, "not integral type"); + static_assert(Begin >= 0, "unexpected argument (Begin<0)"); + using TResult = integer_sequence<TValue, Begin>; +}; +} // namespace detail_ + +template <class T, T N> +using make_integer_sequence = typename detail_::IntSeqImpl<T, 0, N, (N - 0) == 1>::TResult; + +template <std::size_t N> +using make_index_sequence = make_integer_sequence<std::size_t, N>; + +template <class... T> +using index_sequence_for = make_index_sequence<sizeof...(T)>; + +} // namespace ROBIN_HOOD_STD + +#endif + +namespace detail { + +// make sure we static_cast to the correct type for hash_int +#if ROBIN_HOOD(BITNESS) == 64 +using SizeT = uint64_t; +#else +using SizeT = uint32_t; +#endif + +template <typename T> +T rotr(T x, unsigned k) { + return (x >> k) | (x << (8U * sizeof(T) - k)); +} + +// This cast gets rid of warnings like "cast from 'uint8_t*' {aka 'unsigned char*'} to +// 'uint64_t*' {aka 'long unsigned int*'} increases required alignment of target type". Use with +// care! +template <typename T> +inline T reinterpret_cast_no_cast_align_warning(void* ptr) noexcept { + return reinterpret_cast<T>(ptr); +} + +template <typename T> +inline T reinterpret_cast_no_cast_align_warning(void const* ptr) noexcept { + return reinterpret_cast<T>(ptr); +} + +// make sure this is not inlined as it is slow and dramatically enlarges code, thus making other +// inlinings more difficult. Throws are also generally the slow path. +template <typename E, typename... Args> +[[noreturn]] ROBIN_HOOD(NOINLINE) +#if ROBIN_HOOD(HAS_EXCEPTIONS) + void doThrow(Args&&... args) { + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-array-to-pointer-decay) + throw E(std::forward<Args>(args)...); +} +#else + void doThrow(Args&&... ROBIN_HOOD_UNUSED(args) /*unused*/) { + abort(); +} +#endif + +template <typename E, typename T, typename... Args> +T* assertNotNull(T* t, Args&&... args) { + if (ROBIN_HOOD_UNLIKELY(nullptr == t)) { + doThrow<E>(std::forward<Args>(args)...); + } + return t; +} + +template <typename T> +inline T unaligned_load(void const* ptr) noexcept { + // using memcpy so we don't get into unaligned load problems. + // compiler should optimize this very well anyways. + T t; + std::memcpy(&t, ptr, sizeof(T)); + return t; +} + +// Allocates bulks of memory for objects of type T. This deallocates the memory in the destructor, +// and keeps a linked list of the allocated memory around. Overhead per allocation is the size of a +// pointer. +template <typename T, size_t MinNumAllocs = 4, size_t MaxNumAllocs = 256> +class BulkPoolAllocator { +public: + BulkPoolAllocator() noexcept = default; + + // does not copy anything, just creates a new allocator. + BulkPoolAllocator(const BulkPoolAllocator& ROBIN_HOOD_UNUSED(o) /*unused*/) noexcept + : mHead(nullptr) + , mListForFree(nullptr) {} + + BulkPoolAllocator(BulkPoolAllocator&& o) noexcept + : mHead(o.mHead) + , mListForFree(o.mListForFree) { + o.mListForFree = nullptr; + o.mHead = nullptr; + } + + BulkPoolAllocator& operator=(BulkPoolAllocator&& o) noexcept { + reset(); + mHead = o.mHead; + mListForFree = o.mListForFree; + o.mListForFree = nullptr; + o.mHead = nullptr; + return *this; + } + + BulkPoolAllocator& + // NOLINTNEXTLINE(bugprone-unhandled-self-assignment,cert-oop54-cpp) + operator=(const BulkPoolAllocator& ROBIN_HOOD_UNUSED(o) /*unused*/) noexcept { + // does not do anything + return *this; + } + + ~BulkPoolAllocator() noexcept { + reset(); + } + + // Deallocates all allocated memory. + void reset() noexcept { + while (mListForFree) { + T* tmp = *mListForFree; + ROBIN_HOOD_LOG("std::free") + std::free(mListForFree); + mListForFree = reinterpret_cast_no_cast_align_warning<T**>(tmp); + } + mHead = nullptr; + } + + // allocates, but does NOT initialize. Use in-place new constructor, e.g. + // T* obj = pool.allocate(); + // ::new (static_cast<void*>(obj)) T(); + T* allocate() { + T* tmp = mHead; + if (!tmp) { + tmp = performAllocation(); + } + + mHead = *reinterpret_cast_no_cast_align_warning<T**>(tmp); + return tmp; + } + + // does not actually deallocate but puts it in store. + // make sure you have already called the destructor! e.g. with + // obj->~T(); + // pool.deallocate(obj); + void deallocate(T* obj) noexcept { + *reinterpret_cast_no_cast_align_warning<T**>(obj) = mHead; + mHead = obj; + } + + // Adds an already allocated block of memory to the allocator. This allocator is from now on + // responsible for freeing the data (with free()). If the provided data is not large enough to + // make use of, it is immediately freed. Otherwise it is reused and freed in the destructor. + void addOrFree(void* ptr, const size_t numBytes) noexcept { + // calculate number of available elements in ptr + if (numBytes < ALIGNMENT + ALIGNED_SIZE) { + // not enough data for at least one element. Free and return. + ROBIN_HOOD_LOG("std::free") + std::free(ptr); + } else { + ROBIN_HOOD_LOG("add to buffer") + add(ptr, numBytes); + } + } + + void swap(BulkPoolAllocator<T, MinNumAllocs, MaxNumAllocs>& other) noexcept { + using std::swap; + swap(mHead, other.mHead); + swap(mListForFree, other.mListForFree); + } + +private: + // iterates the list of allocated memory to calculate how many to alloc next. + // Recalculating this each time saves us a size_t member. + // This ignores the fact that memory blocks might have been added manually with addOrFree. In + // practice, this should not matter much. + ROBIN_HOOD(NODISCARD) size_t calcNumElementsToAlloc() const noexcept { + auto tmp = mListForFree; + size_t numAllocs = MinNumAllocs; + + while (numAllocs * 2 <= MaxNumAllocs && tmp) { + auto x = reinterpret_cast<T***>(tmp); + tmp = *x; + numAllocs *= 2; + } + + return numAllocs; + } + + // WARNING: Underflow if numBytes < ALIGNMENT! This is guarded in addOrFree(). + void add(void* ptr, const size_t numBytes) noexcept { + const size_t numElements = (numBytes - ALIGNMENT) / ALIGNED_SIZE; + + auto data = reinterpret_cast<T**>(ptr); + + // link free list + auto x = reinterpret_cast<T***>(data); + *x = mListForFree; + mListForFree = data; + + // create linked list for newly allocated data + auto* const headT = + reinterpret_cast_no_cast_align_warning<T*>(reinterpret_cast<char*>(ptr) + ALIGNMENT); + + auto* const head = reinterpret_cast<char*>(headT); + + // Visual Studio compiler automatically unrolls this loop, which is pretty cool + for (size_t i = 0; i < numElements; ++i) { + *reinterpret_cast_no_cast_align_warning<char**>(head + i * ALIGNED_SIZE) = + head + (i + 1) * ALIGNED_SIZE; + } + + // last one points to 0 + *reinterpret_cast_no_cast_align_warning<T**>(head + (numElements - 1) * ALIGNED_SIZE) = + mHead; + mHead = headT; + } + + // Called when no memory is available (mHead == 0). + // Don't inline this slow path. + ROBIN_HOOD(NOINLINE) T* performAllocation() { + size_t const numElementsToAlloc = calcNumElementsToAlloc(); + + // alloc new memory: [prev |T, T, ... T] + size_t const bytes = ALIGNMENT + ALIGNED_SIZE * numElementsToAlloc; + ROBIN_HOOD_LOG("std::malloc " << bytes << " = " << ALIGNMENT << " + " << ALIGNED_SIZE + << " * " << numElementsToAlloc) + add(assertNotNull<std::bad_alloc>(std::malloc(bytes)), bytes); + return mHead; + } + + // enforce byte alignment of the T's +#if ROBIN_HOOD(CXX) >= ROBIN_HOOD(CXX14) + static constexpr size_t ALIGNMENT = + (std::max)(std::alignment_of<T>::value, std::alignment_of<T*>::value); +#else + static const size_t ALIGNMENT = + (ROBIN_HOOD_STD::alignment_of<T>::value > ROBIN_HOOD_STD::alignment_of<T*>::value) + ? ROBIN_HOOD_STD::alignment_of<T>::value + : +ROBIN_HOOD_STD::alignment_of<T*>::value; // the + is for walkarround +#endif + + static constexpr size_t ALIGNED_SIZE = ((sizeof(T) - 1) / ALIGNMENT + 1) * ALIGNMENT; + + static_assert(MinNumAllocs >= 1, "MinNumAllocs"); + static_assert(MaxNumAllocs >= MinNumAllocs, "MaxNumAllocs"); + static_assert(ALIGNED_SIZE >= sizeof(T*), "ALIGNED_SIZE"); + static_assert(0 == (ALIGNED_SIZE % sizeof(T*)), "ALIGNED_SIZE mod"); + static_assert(ALIGNMENT >= sizeof(T*), "ALIGNMENT"); + + T* mHead{nullptr}; + T** mListForFree{nullptr}; +}; + +template <typename T, size_t MinSize, size_t MaxSize, bool IsFlat> +struct NodeAllocator; + +// dummy allocator that does nothing +template <typename T, size_t MinSize, size_t MaxSize> +struct NodeAllocator<T, MinSize, MaxSize, true> { + + // we are not using the data, so just free it. + void addOrFree(void* ptr, size_t ROBIN_HOOD_UNUSED(numBytes) /*unused*/) noexcept { + ROBIN_HOOD_LOG("std::free") + std::free(ptr); + } +}; + +template <typename T, size_t MinSize, size_t MaxSize> +struct NodeAllocator<T, MinSize, MaxSize, false> : public BulkPoolAllocator<T, MinSize, MaxSize> {}; + +// c++14 doesn't have is_nothrow_swappable, and clang++ 6.0.1 doesn't like it either, so I'm making +// my own here. +namespace swappable { +#if ROBIN_HOOD(CXX) < ROBIN_HOOD(CXX17) +using std::swap; +template <typename T> +struct nothrow { + static const bool value = noexcept(swap(std::declval<T&>(), std::declval<T&>())); +}; +#else +template <typename T> +struct nothrow { + static const bool value = std::is_nothrow_swappable<T>::value; +}; +#endif +} // namespace swappable + +} // namespace detail + +struct is_transparent_tag {}; + +// A custom pair implementation is used in the map because std::pair is not is_trivially_copyable, +// which means it would not be allowed to be used in std::memcpy. This struct is copyable, which is +// also tested. +template <typename T1, typename T2> +struct pair { + using first_type = T1; + using second_type = T2; + + template <typename U1 = T1, typename U2 = T2, + typename = typename std::enable_if<std::is_default_constructible<U1>::value && + std::is_default_constructible<U2>::value>::type> + constexpr pair() noexcept(noexcept(U1()) && noexcept(U2())) + : first() + , second() {} + + // pair constructors are explicit so we don't accidentally call this ctor when we don't have to. + explicit constexpr pair(std::pair<T1, T2> const& o) noexcept( + noexcept(T1(std::declval<T1 const&>())) && noexcept(T2(std::declval<T2 const&>()))) + : first(o.first) + , second(o.second) {} + + // pair constructors are explicit so we don't accidentally call this ctor when we don't have to. + explicit constexpr pair(std::pair<T1, T2>&& o) noexcept(noexcept( + T1(std::move(std::declval<T1&&>()))) && noexcept(T2(std::move(std::declval<T2&&>())))) + : first(std::move(o.first)) + , second(std::move(o.second)) {} + + constexpr pair(T1&& a, T2&& b) noexcept(noexcept( + T1(std::move(std::declval<T1&&>()))) && noexcept(T2(std::move(std::declval<T2&&>())))) + : first(std::move(a)) + , second(std::move(b)) {} + + template <typename U1, typename U2> + constexpr pair(U1&& a, U2&& b) noexcept(noexcept(T1(std::forward<U1>( + std::declval<U1&&>()))) && noexcept(T2(std::forward<U2>(std::declval<U2&&>())))) + : first(std::forward<U1>(a)) + , second(std::forward<U2>(b)) {} + + template <typename... U1, typename... U2> + // MSVC 2015 produces error "C2476: ‘constexpr’ constructor does not initialize all members" + // if this constructor is constexpr +#if !ROBIN_HOOD(BROKEN_CONSTEXPR) + constexpr +#endif + pair(std::piecewise_construct_t /*unused*/, std::tuple<U1...> a, + std::tuple<U2...> + b) noexcept(noexcept(pair(std::declval<std::tuple<U1...>&>(), + std::declval<std::tuple<U2...>&>(), + ROBIN_HOOD_STD::index_sequence_for<U1...>(), + ROBIN_HOOD_STD::index_sequence_for<U2...>()))) + : pair(a, b, ROBIN_HOOD_STD::index_sequence_for<U1...>(), + ROBIN_HOOD_STD::index_sequence_for<U2...>()) { + } + + // constructor called from the std::piecewise_construct_t ctor + template <typename... U1, size_t... I1, typename... U2, size_t... I2> + pair(std::tuple<U1...>& a, std::tuple<U2...>& b, ROBIN_HOOD_STD::index_sequence<I1...> /*unused*/, ROBIN_HOOD_STD::index_sequence<I2...> /*unused*/) noexcept( + noexcept(T1(std::forward<U1>(std::get<I1>( + std::declval<std::tuple< + U1...>&>()))...)) && noexcept(T2(std:: + forward<U2>(std::get<I2>( + std::declval<std::tuple<U2...>&>()))...))) + : first(std::forward<U1>(std::get<I1>(a))...) + , second(std::forward<U2>(std::get<I2>(b))...) { + // make visual studio compiler happy about warning about unused a & b. + // Visual studio's pair implementation disables warning 4100. + (void)a; + (void)b; + } + + void swap(pair<T1, T2>& o) noexcept((detail::swappable::nothrow<T1>::value) && + (detail::swappable::nothrow<T2>::value)) { + using std::swap; + swap(first, o.first); + swap(second, o.second); + } + + T1 first; // NOLINT(misc-non-private-member-variables-in-classes) + T2 second; // NOLINT(misc-non-private-member-variables-in-classes) +}; + +template <typename A, typename B> +inline void swap(pair<A, B>& a, pair<A, B>& b) noexcept( + noexcept(std::declval<pair<A, B>&>().swap(std::declval<pair<A, B>&>()))) { + a.swap(b); +} + +template <typename A, typename B> +inline constexpr bool operator==(pair<A, B> const& x, pair<A, B> const& y) { + return (x.first == y.first) && (x.second == y.second); +} +template <typename A, typename B> +inline constexpr bool operator!=(pair<A, B> const& x, pair<A, B> const& y) { + return !(x == y); +} +template <typename A, typename B> +inline constexpr bool operator<(pair<A, B> const& x, pair<A, B> const& y) noexcept(noexcept( + std::declval<A const&>() < std::declval<A const&>()) && noexcept(std::declval<B const&>() < + std::declval<B const&>())) { + return x.first < y.first || (!(y.first < x.first) && x.second < y.second); +} +template <typename A, typename B> +inline constexpr bool operator>(pair<A, B> const& x, pair<A, B> const& y) { + return y < x; +} +template <typename A, typename B> +inline constexpr bool operator<=(pair<A, B> const& x, pair<A, B> const& y) { + return !(x > y); +} +template <typename A, typename B> +inline constexpr bool operator>=(pair<A, B> const& x, pair<A, B> const& y) { + return !(x < y); +} + +inline size_t hash_bytes(void const* ptr, size_t len) noexcept { + static constexpr uint64_t m = UINT64_C(0xc6a4a7935bd1e995); + static constexpr uint64_t seed = UINT64_C(0xe17a1465); + static constexpr unsigned int r = 47; + + auto const* const data64 = static_cast<uint64_t const*>(ptr); + uint64_t h = seed ^ (len * m); + + size_t const n_blocks = len / 8; + for (size_t i = 0; i < n_blocks; ++i) { + auto k = detail::unaligned_load<uint64_t>(data64 + i); + + k *= m; + k ^= k >> r; + k *= m; + + h ^= k; + h *= m; + } + + auto const* const data8 = reinterpret_cast<uint8_t const*>(data64 + n_blocks); + switch (len & 7U) { + case 7: + h ^= static_cast<uint64_t>(data8[6]) << 48U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 6: + h ^= static_cast<uint64_t>(data8[5]) << 40U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 5: + h ^= static_cast<uint64_t>(data8[4]) << 32U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 4: + h ^= static_cast<uint64_t>(data8[3]) << 24U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 3: + h ^= static_cast<uint64_t>(data8[2]) << 16U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 2: + h ^= static_cast<uint64_t>(data8[1]) << 8U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 1: + h ^= static_cast<uint64_t>(data8[0]); + h *= m; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + default: + break; + } + + h ^= h >> r; + + // not doing the final step here, because this will be done by keyToIdx anyways + // h *= m; + // h ^= h >> r; + return static_cast<size_t>(h); +} + +inline size_t hash_int(uint64_t x) noexcept { + // tried lots of different hashes, let's stick with murmurhash3. It's simple, fast, well tested, + // and doesn't need any special 128bit operations. + x ^= x >> 33U; + x *= UINT64_C(0xff51afd7ed558ccd); + x ^= x >> 33U; + + // not doing the final step here, because this will be done by keyToIdx anyways + // x *= UINT64_C(0xc4ceb9fe1a85ec53); + // x ^= x >> 33U; + return static_cast<size_t>(x); +} + +// A thin wrapper around std::hash, performing an additional simple mixing step of the result. +template <typename T, typename Enable = void> +struct hash : public std::hash<T> { + size_t operator()(T const& obj) const + noexcept(noexcept(std::declval<std::hash<T>>().operator()(std::declval<T const&>()))) { + // call base hash + auto result = std::hash<T>::operator()(obj); + // return mixed of that, to be save against identity has + return hash_int(static_cast<detail::SizeT>(result)); + } +}; + +template <typename CharT> +struct hash<std::basic_string<CharT>> { + size_t operator()(std::basic_string<CharT> const& str) const noexcept { + return hash_bytes(str.data(), sizeof(CharT) * str.size()); + } +}; + +#if ROBIN_HOOD(CXX) >= ROBIN_HOOD(CXX17) +template <typename CharT> +struct hash<std::basic_string_view<CharT>> { + size_t operator()(std::basic_string_view<CharT> const& sv) const noexcept { + return hash_bytes(sv.data(), sizeof(CharT) * sv.size()); + } +}; +#endif + +template <class T> +struct hash<T*> { + size_t operator()(T* ptr) const noexcept { + return hash_int(reinterpret_cast<detail::SizeT>(ptr)); + } +}; + +template <class T> +struct hash<std::unique_ptr<T>> { + size_t operator()(std::unique_ptr<T> const& ptr) const noexcept { + return hash_int(reinterpret_cast<detail::SizeT>(ptr.get())); + } +}; + +template <class T> +struct hash<std::shared_ptr<T>> { + size_t operator()(std::shared_ptr<T> const& ptr) const noexcept { + return hash_int(reinterpret_cast<detail::SizeT>(ptr.get())); + } +}; + +template <typename Enum> +struct hash<Enum, typename std::enable_if<std::is_enum<Enum>::value>::type> { + size_t operator()(Enum e) const noexcept { + using Underlying = typename std::underlying_type<Enum>::type; + return hash<Underlying>{}(static_cast<Underlying>(e)); + } +}; + +#define ROBIN_HOOD_HASH_INT(T) \ + template <> \ + struct hash<T> { \ + size_t operator()(T const& obj) const noexcept { \ + return hash_int(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 +ROBIN_HOOD_HASH_INT(bool); +ROBIN_HOOD_HASH_INT(char); +ROBIN_HOOD_HASH_INT(signed char); +ROBIN_HOOD_HASH_INT(unsigned char); +ROBIN_HOOD_HASH_INT(char16_t); +ROBIN_HOOD_HASH_INT(char32_t); +#if ROBIN_HOOD(HAS_NATIVE_WCHART) +ROBIN_HOOD_HASH_INT(wchar_t); +#endif +ROBIN_HOOD_HASH_INT(short); +ROBIN_HOOD_HASH_INT(unsigned short); +ROBIN_HOOD_HASH_INT(int); +ROBIN_HOOD_HASH_INT(unsigned int); +ROBIN_HOOD_HASH_INT(long); +ROBIN_HOOD_HASH_INT(long long); +ROBIN_HOOD_HASH_INT(unsigned long); +ROBIN_HOOD_HASH_INT(unsigned long long); +#if defined(__GNUC__) && !defined(__clang__) +# pragma GCC diagnostic pop +#endif +namespace detail { + +template <typename T> +struct void_type { + using type = void; +}; + +template <typename T, typename = void> +struct has_is_transparent : public std::false_type {}; + +template <typename T> +struct has_is_transparent<T, typename void_type<typename T::is_transparent>::type> + : public std::true_type {}; + +// using wrapper classes for hash and key_equal prevents the diamond problem when the same type +// is used. see https://stackoverflow.com/a/28771920/48181 +template <typename T> +struct WrapHash : public T { + WrapHash() = default; + explicit WrapHash(T const& o) noexcept(noexcept(T(std::declval<T const&>()))) + : T(o) {} +}; + +template <typename T> +struct WrapKeyEqual : public T { + WrapKeyEqual() = default; + explicit WrapKeyEqual(T const& o) noexcept(noexcept(T(std::declval<T const&>()))) + : T(o) {} +}; + +// A highly optimized hashmap implementation, using the Robin Hood algorithm. +// +// In most cases, this map should be usable as a drop-in replacement for std::unordered_map, but +// be about 2x faster in most cases and require much less allocations. +// +// This implementation uses the following memory layout: +// +// [Node, Node, ... Node | info, info, ... infoSentinel ] +// +// * Node: either a DataNode that directly has the std::pair<key, val> as member, +// or a DataNode with a pointer to std::pair<key,val>. Which DataNode representation to use +// depends on how fast the swap() operation is. Heuristically, this is automatically choosen +// based on sizeof(). there are always 2^n Nodes. +// +// * info: Each Node in the map has a corresponding info byte, so there are 2^n info bytes. +// Each byte is initialized to 0, meaning the corresponding Node is empty. Set to 1 means the +// corresponding node contains data. Set to 2 means the corresponding Node is filled, but it +// actually belongs to the previous position and was pushed out because that place is already +// taken. +// +// * infoSentinel: Sentinel byte set to 1, so that iterator's ++ can stop at end() without the +// need for a idx variable. +// +// According to STL, order of templates has effect on throughput. That's why I've moved the +// boolean to the front. +// https://www.reddit.com/r/cpp/comments/ahp6iu/compile_time_binary_size_reductions_and_cs_future/eeguck4/ +template <bool IsFlat, size_t MaxLoadFactor100, typename Key, typename T, typename Hash, + typename KeyEqual> +class Table + : public WrapHash<Hash>, + public WrapKeyEqual<KeyEqual>, + detail::NodeAllocator< + typename std::conditional< + std::is_void<T>::value, Key, + robin_hood::pair<typename std::conditional<IsFlat, Key, Key const>::type, T>>::type, + 4, 16384, IsFlat> { +public: + static constexpr bool is_flat = IsFlat; + static constexpr bool is_map = !std::is_void<T>::value; + static constexpr bool is_set = !is_map; + static constexpr bool is_transparent = + has_is_transparent<Hash>::value && has_is_transparent<KeyEqual>::value; + + using key_type = Key; + using mapped_type = T; + using value_type = typename std::conditional< + is_set, Key, + robin_hood::pair<typename std::conditional<is_flat, Key, Key const>::type, T>>::type; + using size_type = size_t; + using hasher = Hash; + using key_equal = KeyEqual; + using Self = Table<IsFlat, MaxLoadFactor100, key_type, mapped_type, hasher, key_equal>; + +private: + static_assert(MaxLoadFactor100 > 10 && MaxLoadFactor100 < 100, + "MaxLoadFactor100 needs to be >10 && < 100"); + + using WHash = WrapHash<Hash>; + using WKeyEqual = WrapKeyEqual<KeyEqual>; + + // configuration defaults + + // make sure we have 8 elements, needed to quickly rehash mInfo + static constexpr size_t InitialNumElements = sizeof(uint64_t); + static constexpr uint32_t InitialInfoNumBits = 5; + static constexpr uint8_t InitialInfoInc = 1U << InitialInfoNumBits; + static constexpr size_t InfoMask = InitialInfoInc - 1U; + static constexpr uint8_t InitialInfoHashShift = 0; + using DataPool = detail::NodeAllocator<value_type, 4, 16384, IsFlat>; + + // type needs to be wider than uint8_t. + using InfoType = uint32_t; + + // DataNode //////////////////////////////////////////////////////// + + // Primary template for the data node. We have special implementations for small and big + // objects. For large objects it is assumed that swap() is fairly slow, so we allocate these + // on the heap so swap merely swaps a pointer. + template <typename M, bool> + class DataNode {}; + + // Small: just allocate on the stack. + template <typename M> + class DataNode<M, true> final { + public: + template <typename... Args> + explicit DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, Args&&... args) noexcept( + noexcept(value_type(std::forward<Args>(args)...))) + : mData(std::forward<Args>(args)...) {} + + DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, DataNode<M, true>&& n) noexcept( + std::is_nothrow_move_constructible<value_type>::value) + : mData(std::move(n.mData)) {} + + // doesn't do anything + void destroy(M& ROBIN_HOOD_UNUSED(map) /*unused*/) noexcept {} + void destroyDoNotDeallocate() noexcept {} + + value_type const* operator->() const noexcept { + return &mData; + } + value_type* operator->() noexcept { + return &mData; + } + + const value_type& operator*() const noexcept { + return mData; + } + + value_type& operator*() noexcept { + return mData; + } + + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, typename VT::first_type&>::type getFirst() noexcept { + return mData.first; + } + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_set, VT&>::type getFirst() noexcept { + return mData; + } + + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, typename VT::first_type const&>::type + getFirst() const noexcept { + return mData.first; + } + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_set, VT const&>::type getFirst() const noexcept { + return mData; + } + + template <typename MT = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, MT&>::type getSecond() noexcept { + return mData.second; + } + + template <typename MT = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_set, MT const&>::type getSecond() const noexcept { + return mData.second; + } + + void swap(DataNode<M, true>& o) noexcept( + noexcept(std::declval<value_type>().swap(std::declval<value_type>()))) { + mData.swap(o.mData); + } + + private: + value_type mData; + }; + + // big object: allocate on heap. + template <typename M> + class DataNode<M, false> { + public: + template <typename... Args> + explicit DataNode(M& map, Args&&... args) + : mData(map.allocate()) { + ::new (static_cast<void*>(mData)) value_type(std::forward<Args>(args)...); + } + + DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, DataNode<M, false>&& n) noexcept + : mData(std::move(n.mData)) {} + + void destroy(M& map) noexcept { + // don't deallocate, just put it into list of datapool. + mData->~value_type(); + map.deallocate(mData); + } + + void destroyDoNotDeallocate() noexcept { + mData->~value_type(); + } + + value_type const* operator->() const noexcept { + return mData; + } + + value_type* operator->() noexcept { + return mData; + } + + const value_type& operator*() const { + return *mData; + } + + value_type& operator*() { + return *mData; + } + + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, typename VT::first_type&>::type getFirst() noexcept { + return mData->first; + } + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_set, VT&>::type getFirst() noexcept { + return *mData; + } + + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, typename VT::first_type const&>::type + getFirst() const noexcept { + return mData->first; + } + template <typename VT = value_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_set, VT const&>::type getFirst() const noexcept { + return *mData; + } + + template <typename MT = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, MT&>::type getSecond() noexcept { + return mData->second; + } + + template <typename MT = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<is_map, MT const&>::type getSecond() const noexcept { + return mData->second; + } + + void swap(DataNode<M, false>& o) noexcept { + using std::swap; + swap(mData, o.mData); + } + + private: + value_type* mData; + }; + + using Node = DataNode<Self, IsFlat>; + + // helpers for insertKeyPrepareEmptySpot: extract first entry (only const required) + ROBIN_HOOD(NODISCARD) key_type const& getFirstConst(Node const& n) const noexcept { + return n.getFirst(); + } + + // in case we have void mapped_type, we are not using a pair, thus we just route k through. + // No need to disable this because it's just not used if not applicable. + ROBIN_HOOD(NODISCARD) key_type const& getFirstConst(key_type const& k) const noexcept { + return k; + } + + // in case we have non-void mapped_type, we have a standard robin_hood::pair + template <typename Q = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<!std::is_void<Q>::value, key_type const&>::type + getFirstConst(value_type const& vt) const noexcept { + return vt.first; + } + + // Cloner ////////////////////////////////////////////////////////// + + template <typename M, bool UseMemcpy> + struct Cloner; + + // fast path: Just copy data, without allocating anything. + template <typename M> + struct Cloner<M, true> { + void operator()(M const& source, M& target) const { + auto const* const src = reinterpret_cast<char const*>(source.mKeyVals); + auto* tgt = reinterpret_cast<char*>(target.mKeyVals); + auto const numElementsWithBuffer = target.calcNumElementsWithBuffer(target.mMask + 1); + std::copy(src, src + target.calcNumBytesTotal(numElementsWithBuffer), tgt); + } + }; + + template <typename M> + struct Cloner<M, false> { + void operator()(M const& s, M& t) const { + auto const numElementsWithBuffer = t.calcNumElementsWithBuffer(t.mMask + 1); + std::copy(s.mInfo, s.mInfo + t.calcNumBytesInfo(numElementsWithBuffer), t.mInfo); + + for (size_t i = 0; i < numElementsWithBuffer; ++i) { + if (t.mInfo[i]) { + ::new (static_cast<void*>(t.mKeyVals + i)) Node(t, *s.mKeyVals[i]); + } + } + } + }; + + // Destroyer /////////////////////////////////////////////////////// + + template <typename M, bool IsFlatAndTrivial> + struct Destroyer {}; + + template <typename M> + struct Destroyer<M, true> { + void nodes(M& m) const noexcept { + m.mNumElements = 0; + } + + void nodesDoNotDeallocate(M& m) const noexcept { + m.mNumElements = 0; + } + }; + + template <typename M> + struct Destroyer<M, false> { + void nodes(M& m) const noexcept { + m.mNumElements = 0; + // clear also resets mInfo to 0, that's sometimes not necessary. + auto const numElementsWithBuffer = m.calcNumElementsWithBuffer(m.mMask + 1); + + for (size_t idx = 0; idx < numElementsWithBuffer; ++idx) { + if (0 != m.mInfo[idx]) { + Node& n = m.mKeyVals[idx]; + n.destroy(m); + n.~Node(); + } + } + } + + void nodesDoNotDeallocate(M& m) const noexcept { + m.mNumElements = 0; + // clear also resets mInfo to 0, that's sometimes not necessary. + auto const numElementsWithBuffer = m.calcNumElementsWithBuffer(m.mMask + 1); + for (size_t idx = 0; idx < numElementsWithBuffer; ++idx) { + if (0 != m.mInfo[idx]) { + Node& n = m.mKeyVals[idx]; + n.destroyDoNotDeallocate(); + n.~Node(); + } + } + } + }; + + // Iter //////////////////////////////////////////////////////////// + + struct fast_forward_tag {}; + + // generic iterator for both const_iterator and iterator. + template <bool IsConst> + // NOLINTNEXTLINE(hicpp-special-member-functions,cppcoreguidelines-special-member-functions) + class Iter { + private: + using NodePtr = typename std::conditional<IsConst, Node const*, Node*>::type; + + public: + using difference_type = std::ptrdiff_t; + using value_type = typename Self::value_type; + using reference = typename std::conditional<IsConst, value_type const&, value_type&>::type; + using pointer = typename std::conditional<IsConst, value_type const*, value_type*>::type; + using iterator_category = std::forward_iterator_tag; + + // default constructed iterator can be compared to itself, but WON'T return true when + // compared to end(). + Iter() = default; + + // Rule of zero: nothing specified. The conversion constructor is only enabled for + // iterator to const_iterator, so it doesn't accidentally work as a copy ctor. + + // Conversion constructor from iterator to const_iterator. + template <bool OtherIsConst, + typename = typename std::enable_if<IsConst && !OtherIsConst>::type> + // NOLINTNEXTLINE(hicpp-explicit-conversions) + Iter(Iter<OtherIsConst> const& other) noexcept + : mKeyVals(other.mKeyVals) + , mInfo(other.mInfo) {} + + Iter(NodePtr valPtr, uint8_t const* infoPtr) noexcept + : mKeyVals(valPtr) + , mInfo(infoPtr) {} + + Iter(NodePtr valPtr, uint8_t const* infoPtr, + fast_forward_tag ROBIN_HOOD_UNUSED(tag) /*unused*/) noexcept + : mKeyVals(valPtr) + , mInfo(infoPtr) { + fastForward(); + } + + template <bool OtherIsConst, + typename = typename std::enable_if<IsConst && !OtherIsConst>::type> + Iter& operator=(Iter<OtherIsConst> const& other) noexcept { + mKeyVals = other.mKeyVals; + mInfo = other.mInfo; + return *this; + } + + // prefix increment. Undefined behavior if we are at end()! + Iter& operator++() noexcept { + mInfo++; + mKeyVals++; + fastForward(); + return *this; + } + + Iter operator++(int) noexcept { + Iter tmp = *this; + ++(*this); + return tmp; + } + + reference operator*() const { + return **mKeyVals; + } + + pointer operator->() const { + return &**mKeyVals; + } + + template <bool O> + bool operator==(Iter<O> const& o) const noexcept { + return mKeyVals == o.mKeyVals; + } + + template <bool O> + bool operator!=(Iter<O> const& o) const noexcept { + return mKeyVals != o.mKeyVals; + } + + private: + // fast forward to the next non-free info byte + // I've tried a few variants that don't depend on intrinsics, but unfortunately they are + // quite a bit slower than this one. So I've reverted that change again. See map_benchmark. + void fastForward() noexcept { + size_t n = 0; + while (0U == (n = detail::unaligned_load<size_t>(mInfo))) { + mInfo += sizeof(size_t); + mKeyVals += sizeof(size_t); + } +#if defined(ROBIN_HOOD_DISABLE_INTRINSICS) + // we know for certain that within the next 8 bytes we'll find a non-zero one. + if (ROBIN_HOOD_UNLIKELY(0U == detail::unaligned_load<uint32_t>(mInfo))) { + mInfo += 4; + mKeyVals += 4; + } + if (ROBIN_HOOD_UNLIKELY(0U == detail::unaligned_load<uint16_t>(mInfo))) { + mInfo += 2; + mKeyVals += 2; + } + if (ROBIN_HOOD_UNLIKELY(0U == *mInfo)) { + mInfo += 1; + mKeyVals += 1; + } +#else +# if ROBIN_HOOD(LITTLE_ENDIAN) + auto inc = ROBIN_HOOD_COUNT_TRAILING_ZEROES(n) / 8; +# else + auto inc = ROBIN_HOOD_COUNT_LEADING_ZEROES(n) / 8; +# endif + mInfo += inc; + mKeyVals += inc; +#endif + } + + friend class Table<IsFlat, MaxLoadFactor100, key_type, mapped_type, hasher, key_equal>; + NodePtr mKeyVals{nullptr}; + uint8_t const* mInfo{nullptr}; + }; + + //////////////////////////////////////////////////////////////////// + + // highly performance relevant code. + // Lower bits are used for indexing into the array (2^n size) + // The upper 1-5 bits need to be a reasonable good hash, to save comparisons. + template <typename HashKey> + void keyToIdx(HashKey&& key, size_t* idx, InfoType* info) const { + // In addition to whatever hash is used, add another mul & shift so we get better hashing. + // This serves as a bad hash prevention, if the given data is + // badly mixed. + auto h = static_cast<uint64_t>(WHash::operator()(key)); + + h *= mHashMultiplier; + h ^= h >> 33U; + + // the lower InitialInfoNumBits are reserved for info. + *info = mInfoInc + static_cast<InfoType>((h & InfoMask) >> mInfoHashShift); + *idx = (static_cast<size_t>(h) >> InitialInfoNumBits) & mMask; + } + + // forwards the index by one, wrapping around at the end + void next(InfoType* info, size_t* idx) const noexcept { + *idx = *idx + 1; + *info += mInfoInc; + } + + void nextWhileLess(InfoType* info, size_t* idx) const noexcept { + // unrolling this by hand did not bring any speedups. + while (*info < mInfo[*idx]) { + next(info, idx); + } + } + + // Shift everything up by one element. Tries to move stuff around. + void + shiftUp(size_t startIdx, + size_t const insertion_idx) noexcept(std::is_nothrow_move_assignable<Node>::value) { + auto idx = startIdx; + ::new (static_cast<void*>(mKeyVals + idx)) Node(std::move(mKeyVals[idx - 1])); + while (--idx != insertion_idx) { + mKeyVals[idx] = std::move(mKeyVals[idx - 1]); + } + + idx = startIdx; + while (idx != insertion_idx) { + ROBIN_HOOD_COUNT(shiftUp) + mInfo[idx] = static_cast<uint8_t>(mInfo[idx - 1] + mInfoInc); + if (ROBIN_HOOD_UNLIKELY(mInfo[idx] + mInfoInc > 0xFF)) { + mMaxNumElementsAllowed = 0; + } + --idx; + } + } + + void shiftDown(size_t idx) noexcept(std::is_nothrow_move_assignable<Node>::value) { + // until we find one that is either empty or has zero offset. + // TODO(martinus) we don't need to move everything, just the last one for the same + // bucket. + mKeyVals[idx].destroy(*this); + + // until we find one that is either empty or has zero offset. + while (mInfo[idx + 1] >= 2 * mInfoInc) { + ROBIN_HOOD_COUNT(shiftDown) + mInfo[idx] = static_cast<uint8_t>(mInfo[idx + 1] - mInfoInc); + mKeyVals[idx] = std::move(mKeyVals[idx + 1]); + ++idx; + } + + mInfo[idx] = 0; + // don't destroy, we've moved it + // mKeyVals[idx].destroy(*this); + mKeyVals[idx].~Node(); + } + + // copy of find(), except that it returns iterator instead of const_iterator. + template <typename Other> + ROBIN_HOOD(NODISCARD) + size_t findIdx(Other const& key) const { + size_t idx{}; + InfoType info{}; + keyToIdx(key, &idx, &info); + + do { + // unrolling this twice gives a bit of a speedup. More unrolling did not help. + if (info == mInfo[idx] && + ROBIN_HOOD_LIKELY(WKeyEqual::operator()(key, mKeyVals[idx].getFirst()))) { + return idx; + } + next(&info, &idx); + if (info == mInfo[idx] && + ROBIN_HOOD_LIKELY(WKeyEqual::operator()(key, mKeyVals[idx].getFirst()))) { + return idx; + } + next(&info, &idx); + } while (info <= mInfo[idx]); + + // nothing found! + return mMask == 0 ? 0 + : static_cast<size_t>(std::distance( + mKeyVals, reinterpret_cast_no_cast_align_warning<Node*>(mInfo))); + } + + void cloneData(const Table& o) { + Cloner<Table, IsFlat && ROBIN_HOOD_IS_TRIVIALLY_COPYABLE(Node)>()(o, *this); + } + + // inserts a keyval that is guaranteed to be new, e.g. when the hashmap is resized. + // @return True on success, false if something went wrong + void insert_move(Node&& keyval) { + // we don't retry, fail if overflowing + // don't need to check max num elements + if (0 == mMaxNumElementsAllowed && !try_increase_info()) { + throwOverflowError(); + } + + size_t idx{}; + InfoType info{}; + keyToIdx(keyval.getFirst(), &idx, &info); + + // skip forward. Use <= because we are certain that the element is not there. + while (info <= mInfo[idx]) { + idx = idx + 1; + info += mInfoInc; + } + + // key not found, so we are now exactly where we want to insert it. + auto const insertion_idx = idx; + auto const insertion_info = static_cast<uint8_t>(info); + if (ROBIN_HOOD_UNLIKELY(insertion_info + mInfoInc > 0xFF)) { + mMaxNumElementsAllowed = 0; + } + + // find an empty spot + while (0 != mInfo[idx]) { + next(&info, &idx); + } + + auto& l = mKeyVals[insertion_idx]; + if (idx == insertion_idx) { + ::new (static_cast<void*>(&l)) Node(std::move(keyval)); + } else { + shiftUp(idx, insertion_idx); + l = std::move(keyval); + } + + // put at empty spot + mInfo[insertion_idx] = insertion_info; + + ++mNumElements; + } + +public: + using iterator = Iter<false>; + using const_iterator = Iter<true>; + + Table() noexcept(noexcept(Hash()) && noexcept(KeyEqual())) + : WHash() + , WKeyEqual() { + ROBIN_HOOD_TRACE(this) + } + + // Creates an empty hash map. Nothing is allocated yet, this happens at the first insert. + // This tremendously speeds up ctor & dtor of a map that never receives an element. The + // penalty is payed at the first insert, and not before. Lookup of this empty map works + // because everybody points to DummyInfoByte::b. parameter bucket_count is dictated by the + // standard, but we can ignore it. + explicit Table( + size_t ROBIN_HOOD_UNUSED(bucket_count) /*unused*/, const Hash& h = Hash{}, + const KeyEqual& equal = KeyEqual{}) noexcept(noexcept(Hash(h)) && noexcept(KeyEqual(equal))) + : WHash(h) + , WKeyEqual(equal) { + ROBIN_HOOD_TRACE(this) + } + + template <typename Iter> + Table(Iter first, Iter last, size_t ROBIN_HOOD_UNUSED(bucket_count) /*unused*/ = 0, + const Hash& h = Hash{}, const KeyEqual& equal = KeyEqual{}) + : WHash(h) + , WKeyEqual(equal) { + ROBIN_HOOD_TRACE(this) + insert(first, last); + } + + Table(std::initializer_list<value_type> initlist, + size_t ROBIN_HOOD_UNUSED(bucket_count) /*unused*/ = 0, const Hash& h = Hash{}, + const KeyEqual& equal = KeyEqual{}) + : WHash(h) + , WKeyEqual(equal) { + ROBIN_HOOD_TRACE(this) + insert(initlist.begin(), initlist.end()); + } + + Table(Table&& o) noexcept + : WHash(std::move(static_cast<WHash&>(o))) + , WKeyEqual(std::move(static_cast<WKeyEqual&>(o))) + , DataPool(std::move(static_cast<DataPool&>(o))) { + ROBIN_HOOD_TRACE(this) + if (o.mMask) { + mHashMultiplier = std::move(o.mHashMultiplier); + mKeyVals = std::move(o.mKeyVals); + mInfo = std::move(o.mInfo); + mNumElements = std::move(o.mNumElements); + mMask = std::move(o.mMask); + mMaxNumElementsAllowed = std::move(o.mMaxNumElementsAllowed); + mInfoInc = std::move(o.mInfoInc); + mInfoHashShift = std::move(o.mInfoHashShift); + // set other's mask to 0 so its destructor won't do anything + o.init(); + } + } + + Table& operator=(Table&& o) noexcept { + ROBIN_HOOD_TRACE(this) + if (&o != this) { + if (o.mMask) { + // only move stuff if the other map actually has some data + destroy(); + mHashMultiplier = std::move(o.mHashMultiplier); + mKeyVals = std::move(o.mKeyVals); + mInfo = std::move(o.mInfo); + mNumElements = std::move(o.mNumElements); + mMask = std::move(o.mMask); + mMaxNumElementsAllowed = std::move(o.mMaxNumElementsAllowed); + mInfoInc = std::move(o.mInfoInc); + mInfoHashShift = std::move(o.mInfoHashShift); + WHash::operator=(std::move(static_cast<WHash&>(o))); + WKeyEqual::operator=(std::move(static_cast<WKeyEqual&>(o))); + DataPool::operator=(std::move(static_cast<DataPool&>(o))); + + o.init(); + + } else { + // nothing in the other map => just clear us. + clear(); + } + } + return *this; + } + + Table(const Table& o) + : WHash(static_cast<const WHash&>(o)) + , WKeyEqual(static_cast<const WKeyEqual&>(o)) + , DataPool(static_cast<const DataPool&>(o)) { + ROBIN_HOOD_TRACE(this) + if (!o.empty()) { + // not empty: create an exact copy. it is also possible to just iterate through all + // elements and insert them, but copying is probably faster. + + auto const numElementsWithBuffer = calcNumElementsWithBuffer(o.mMask + 1); + auto const numBytesTotal = calcNumBytesTotal(numElementsWithBuffer); + + ROBIN_HOOD_LOG("std::malloc " << numBytesTotal << " = calcNumBytesTotal(" + << numElementsWithBuffer << ")") + mHashMultiplier = o.mHashMultiplier; + mKeyVals = static_cast<Node*>( + detail::assertNotNull<std::bad_alloc>(std::malloc(numBytesTotal))); + // no need for calloc because clonData does memcpy + mInfo = reinterpret_cast<uint8_t*>(mKeyVals + numElementsWithBuffer); + mNumElements = o.mNumElements; + mMask = o.mMask; + mMaxNumElementsAllowed = o.mMaxNumElementsAllowed; + mInfoInc = o.mInfoInc; + mInfoHashShift = o.mInfoHashShift; + cloneData(o); + } + } + + // Creates a copy of the given map. Copy constructor of each entry is used. + // Not sure why clang-tidy thinks this doesn't handle self assignment, it does + // NOLINTNEXTLINE(bugprone-unhandled-self-assignment,cert-oop54-cpp) + Table& operator=(Table const& o) { + ROBIN_HOOD_TRACE(this) + if (&o == this) { + // prevent assigning of itself + return *this; + } + + // we keep using the old allocator and not assign the new one, because we want to keep + // the memory available. when it is the same size. + if (o.empty()) { + if (0 == mMask) { + // nothing to do, we are empty too + return *this; + } + + // not empty: destroy what we have there + // clear also resets mInfo to 0, that's sometimes not necessary. + destroy(); + init(); + WHash::operator=(static_cast<const WHash&>(o)); + WKeyEqual::operator=(static_cast<const WKeyEqual&>(o)); + DataPool::operator=(static_cast<DataPool const&>(o)); + + return *this; + } + + // clean up old stuff + Destroyer<Self, IsFlat && std::is_trivially_destructible<Node>::value>{}.nodes(*this); + + if (mMask != o.mMask) { + // no luck: we don't have the same array size allocated, so we need to realloc. + if (0 != mMask) { + // only deallocate if we actually have data! + ROBIN_HOOD_LOG("std::free") + std::free(mKeyVals); + } + + auto const numElementsWithBuffer = calcNumElementsWithBuffer(o.mMask + 1); + auto const numBytesTotal = calcNumBytesTotal(numElementsWithBuffer); + ROBIN_HOOD_LOG("std::malloc " << numBytesTotal << " = calcNumBytesTotal(" + << numElementsWithBuffer << ")") + mKeyVals = static_cast<Node*>( + detail::assertNotNull<std::bad_alloc>(std::malloc(numBytesTotal))); + + // no need for calloc here because cloneData performs a memcpy. + mInfo = reinterpret_cast<uint8_t*>(mKeyVals + numElementsWithBuffer); + // sentinel is set in cloneData + } + WHash::operator=(static_cast<const WHash&>(o)); + WKeyEqual::operator=(static_cast<const WKeyEqual&>(o)); + DataPool::operator=(static_cast<DataPool const&>(o)); + mHashMultiplier = o.mHashMultiplier; + mNumElements = o.mNumElements; + mMask = o.mMask; + mMaxNumElementsAllowed = o.mMaxNumElementsAllowed; + mInfoInc = o.mInfoInc; + mInfoHashShift = o.mInfoHashShift; + cloneData(o); + + return *this; + } + + // Swaps everything between the two maps. + void swap(Table& o) { + ROBIN_HOOD_TRACE(this) + using std::swap; + swap(o, *this); + } + + // Clears all data, without resizing. + void clear() { + ROBIN_HOOD_TRACE(this) + if (empty()) { + // don't do anything! also important because we don't want to write to + // DummyInfoByte::b, even though we would just write 0 to it. + return; + } + + Destroyer<Self, IsFlat && std::is_trivially_destructible<Node>::value>{}.nodes(*this); + + auto const numElementsWithBuffer = calcNumElementsWithBuffer(mMask + 1); + // clear everything, then set the sentinel again + uint8_t const z = 0; + std::fill(mInfo, mInfo + calcNumBytesInfo(numElementsWithBuffer), z); + mInfo[numElementsWithBuffer] = 1; + + mInfoInc = InitialInfoInc; + mInfoHashShift = InitialInfoHashShift; + } + + // Destroys the map and all it's contents. + ~Table() { + ROBIN_HOOD_TRACE(this) + destroy(); + } + + // Checks if both tables contain the same entries. Order is irrelevant. + bool operator==(const Table& other) const { + ROBIN_HOOD_TRACE(this) + if (other.size() != size()) { + return false; + } + for (auto const& otherEntry : other) { + if (!has(otherEntry)) { + return false; + } + } + + return true; + } + + bool operator!=(const Table& other) const { + ROBIN_HOOD_TRACE(this) + return !operator==(other); + } + + template <typename Q = mapped_type> + typename std::enable_if<!std::is_void<Q>::value, Q&>::type operator[](const key_type& key) { + ROBIN_HOOD_TRACE(this) + auto idxAndState = insertKeyPrepareEmptySpot(key); + switch (idxAndState.second) { + case InsertionState::key_found: + break; + + case InsertionState::new_node: + ::new (static_cast<void*>(&mKeyVals[idxAndState.first])) + Node(*this, std::piecewise_construct, std::forward_as_tuple(key), + std::forward_as_tuple()); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = Node(*this, std::piecewise_construct, + std::forward_as_tuple(key), std::forward_as_tuple()); + break; + + case InsertionState::overflow_error: + throwOverflowError(); + } + + return mKeyVals[idxAndState.first].getSecond(); + } + + template <typename Q = mapped_type> + typename std::enable_if<!std::is_void<Q>::value, Q&>::type operator[](key_type&& key) { + ROBIN_HOOD_TRACE(this) + auto idxAndState = insertKeyPrepareEmptySpot(key); + switch (idxAndState.second) { + case InsertionState::key_found: + break; + + case InsertionState::new_node: + ::new (static_cast<void*>(&mKeyVals[idxAndState.first])) + Node(*this, std::piecewise_construct, std::forward_as_tuple(std::move(key)), + std::forward_as_tuple()); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = + Node(*this, std::piecewise_construct, std::forward_as_tuple(std::move(key)), + std::forward_as_tuple()); + break; + + case InsertionState::overflow_error: + throwOverflowError(); + } + + return mKeyVals[idxAndState.first].getSecond(); + } + + template <typename Iter> + void insert(Iter first, Iter last) { + for (; first != last; ++first) { + // value_type ctor needed because this might be called with std::pair's + insert(value_type(*first)); + } + } + + void insert(std::initializer_list<value_type> ilist) { + for (auto&& vt : ilist) { + insert(std::move(vt)); + } + } + + template <typename... Args> + std::pair<iterator, bool> emplace(Args&&... args) { + ROBIN_HOOD_TRACE(this) + Node n{*this, std::forward<Args>(args)...}; + auto idxAndState = insertKeyPrepareEmptySpot(getFirstConst(n)); + switch (idxAndState.second) { + case InsertionState::key_found: + n.destroy(*this); + break; + + case InsertionState::new_node: + ::new (static_cast<void*>(&mKeyVals[idxAndState.first])) Node(*this, std::move(n)); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = std::move(n); + break; + + case InsertionState::overflow_error: + n.destroy(*this); + throwOverflowError(); + break; + } + + return std::make_pair(iterator(mKeyVals + idxAndState.first, mInfo + idxAndState.first), + InsertionState::key_found != idxAndState.second); + } + + template <typename... Args> + iterator emplace_hint(const_iterator position, Args&&... args) { + (void)position; + return emplace(std::forward<Args>(args)...).first; + } + + template <typename... Args> + std::pair<iterator, bool> try_emplace(const key_type& key, Args&&... args) { + return try_emplace_impl(key, std::forward<Args>(args)...); + } + + template <typename... Args> + std::pair<iterator, bool> try_emplace(key_type&& key, Args&&... args) { + return try_emplace_impl(std::move(key), std::forward<Args>(args)...); + } + + template <typename... Args> + iterator try_emplace(const_iterator hint, const key_type& key, Args&&... args) { + (void)hint; + return try_emplace_impl(key, std::forward<Args>(args)...).first; + } + + template <typename... Args> + iterator try_emplace(const_iterator hint, key_type&& key, Args&&... args) { + (void)hint; + return try_emplace_impl(std::move(key), std::forward<Args>(args)...).first; + } + + template <typename Mapped> + std::pair<iterator, bool> insert_or_assign(const key_type& key, Mapped&& obj) { + return insertOrAssignImpl(key, std::forward<Mapped>(obj)); + } + + template <typename Mapped> + std::pair<iterator, bool> insert_or_assign(key_type&& key, Mapped&& obj) { + return insertOrAssignImpl(std::move(key), std::forward<Mapped>(obj)); + } + + template <typename Mapped> + iterator insert_or_assign(const_iterator hint, const key_type& key, Mapped&& obj) { + (void)hint; + return insertOrAssignImpl(key, std::forward<Mapped>(obj)).first; + } + + template <typename Mapped> + iterator insert_or_assign(const_iterator hint, key_type&& key, Mapped&& obj) { + (void)hint; + return insertOrAssignImpl(std::move(key), std::forward<Mapped>(obj)).first; + } + + std::pair<iterator, bool> insert(const value_type& keyval) { + ROBIN_HOOD_TRACE(this) + return emplace(keyval); + } + + iterator insert(const_iterator hint, const value_type& keyval) { + (void)hint; + return emplace(keyval).first; + } + + std::pair<iterator, bool> insert(value_type&& keyval) { + return emplace(std::move(keyval)); + } + + iterator insert(const_iterator hint, value_type&& keyval) { + (void)hint; + return emplace(std::move(keyval)).first; + } + + // Returns 1 if key is found, 0 otherwise. + size_t count(const key_type& key) const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + auto kv = mKeyVals + findIdx(key); + if (kv != reinterpret_cast_no_cast_align_warning<Node*>(mInfo)) { + return 1; + } + return 0; + } + + template <typename OtherKey, typename Self_ = Self> + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if<Self_::is_transparent, size_t>::type count(const OtherKey& key) const { + ROBIN_HOOD_TRACE(this) + auto kv = mKeyVals + findIdx(key); + if (kv != reinterpret_cast_no_cast_align_warning<Node*>(mInfo)) { + return 1; + } + return 0; + } + + bool contains(const key_type& key) const { // NOLINT(modernize-use-nodiscard) + return 1U == count(key); + } + + template <typename OtherKey, typename Self_ = Self> + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if<Self_::is_transparent, bool>::type contains(const OtherKey& key) const { + return 1U == count(key); + } + + // Returns a reference to the value found for key. + // Throws std::out_of_range if element cannot be found + template <typename Q = mapped_type> + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if<!std::is_void<Q>::value, Q&>::type at(key_type const& key) { + ROBIN_HOOD_TRACE(this) + auto kv = mKeyVals + findIdx(key); + if (kv == reinterpret_cast_no_cast_align_warning<Node*>(mInfo)) { + doThrow<std::out_of_range>("key not found"); + } + return kv->getSecond(); + } + + // Returns a reference to the value found for key. + // Throws std::out_of_range if element cannot be found + template <typename Q = mapped_type> + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if<!std::is_void<Q>::value, Q const&>::type at(key_type const& key) const { + ROBIN_HOOD_TRACE(this) + auto kv = mKeyVals + findIdx(key); + if (kv == reinterpret_cast_no_cast_align_warning<Node*>(mInfo)) { + doThrow<std::out_of_range>("key not found"); + } + return kv->getSecond(); + } + + const_iterator find(const key_type& key) const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return const_iterator{mKeyVals + idx, mInfo + idx}; + } + + template <typename OtherKey> + const_iterator find(const OtherKey& key, is_transparent_tag /*unused*/) const { + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return const_iterator{mKeyVals + idx, mInfo + idx}; + } + + template <typename OtherKey, typename Self_ = Self> + typename std::enable_if<Self_::is_transparent, // NOLINT(modernize-use-nodiscard) + const_iterator>::type // NOLINT(modernize-use-nodiscard) + find(const OtherKey& key) const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return const_iterator{mKeyVals + idx, mInfo + idx}; + } + + iterator find(const key_type& key) { + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return iterator{mKeyVals + idx, mInfo + idx}; + } + + template <typename OtherKey> + iterator find(const OtherKey& key, is_transparent_tag /*unused*/) { + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return iterator{mKeyVals + idx, mInfo + idx}; + } + + template <typename OtherKey, typename Self_ = Self> + typename std::enable_if<Self_::is_transparent, iterator>::type find(const OtherKey& key) { + ROBIN_HOOD_TRACE(this) + const size_t idx = findIdx(key); + return iterator{mKeyVals + idx, mInfo + idx}; + } + + iterator begin() { + ROBIN_HOOD_TRACE(this) + if (empty()) { + return end(); + } + return iterator(mKeyVals, mInfo, fast_forward_tag{}); + } + const_iterator begin() const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return cbegin(); + } + const_iterator cbegin() const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + if (empty()) { + return cend(); + } + return const_iterator(mKeyVals, mInfo, fast_forward_tag{}); + } + + iterator end() { + ROBIN_HOOD_TRACE(this) + // no need to supply valid info pointer: end() must not be dereferenced, and only node + // pointer is compared. + return iterator{reinterpret_cast_no_cast_align_warning<Node*>(mInfo), nullptr}; + } + const_iterator end() const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return cend(); + } + const_iterator cend() const { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return const_iterator{reinterpret_cast_no_cast_align_warning<Node*>(mInfo), nullptr}; + } + + iterator erase(const_iterator pos) { + ROBIN_HOOD_TRACE(this) + // its safe to perform const cast here + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast) + return erase(iterator{const_cast<Node*>(pos.mKeyVals), const_cast<uint8_t*>(pos.mInfo)}); + } + + // Erases element at pos, returns iterator to the next element. + iterator erase(iterator pos) { + ROBIN_HOOD_TRACE(this) + // we assume that pos always points to a valid entry, and not end(). + auto const idx = static_cast<size_t>(pos.mKeyVals - mKeyVals); + + shiftDown(idx); + --mNumElements; + + if (*pos.mInfo) { + // we've backward shifted, return this again + return pos; + } + + // no backward shift, return next element + return ++pos; + } + + size_t erase(const key_type& key) { + ROBIN_HOOD_TRACE(this) + size_t idx{}; + InfoType info{}; + keyToIdx(key, &idx, &info); + + // check while info matches with the source idx + do { + if (info == mInfo[idx] && WKeyEqual::operator()(key, mKeyVals[idx].getFirst())) { + shiftDown(idx); + --mNumElements; + return 1; + } + next(&info, &idx); + } while (info <= mInfo[idx]); + + // nothing found to delete + return 0; + } + + // reserves space for the specified number of elements. Makes sure the old data fits. + // exactly the same as reserve(c). + void rehash(size_t c) { + // forces a reserve + reserve(c, true); + } + + // reserves space for the specified number of elements. Makes sure the old data fits. + // Exactly the same as rehash(c). Use rehash(0) to shrink to fit. + void reserve(size_t c) { + // reserve, but don't force rehash + reserve(c, false); + } + + // If possible reallocates the map to a smaller one. This frees the underlying table. + // Does not do anything if load_factor is too large for decreasing the table's size. + void compact() { + ROBIN_HOOD_TRACE(this) + auto newSize = InitialNumElements; + while (calcMaxNumElementsAllowed(newSize) < mNumElements && newSize != 0) { + newSize *= 2; + } + if (ROBIN_HOOD_UNLIKELY(newSize == 0)) { + throwOverflowError(); + } + + ROBIN_HOOD_LOG("newSize > mMask + 1: " << newSize << " > " << mMask << " + 1") + + // only actually do anything when the new size is bigger than the old one. This prevents to + // continuously allocate for each reserve() call. + if (newSize < mMask + 1) { + rehashPowerOfTwo(newSize, true); + } + } + + size_type size() const noexcept { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return mNumElements; + } + + size_type max_size() const noexcept { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return static_cast<size_type>(-1); + } + + ROBIN_HOOD(NODISCARD) bool empty() const noexcept { + ROBIN_HOOD_TRACE(this) + return 0 == mNumElements; + } + + float max_load_factor() const noexcept { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return MaxLoadFactor100 / 100.0F; + } + + // Average number of elements per bucket. Since we allow only 1 per bucket + float load_factor() const noexcept { // NOLINT(modernize-use-nodiscard) + ROBIN_HOOD_TRACE(this) + return static_cast<float>(size()) / static_cast<float>(mMask + 1); + } + + ROBIN_HOOD(NODISCARD) size_t mask() const noexcept { + ROBIN_HOOD_TRACE(this) + return mMask; + } + + ROBIN_HOOD(NODISCARD) size_t calcMaxNumElementsAllowed(size_t maxElements) const noexcept { + if (ROBIN_HOOD_LIKELY(maxElements <= (std::numeric_limits<size_t>::max)() / 100)) { + return maxElements * MaxLoadFactor100 / 100; + } + + // we might be a bit inprecise, but since maxElements is quite large that doesn't matter + return (maxElements / 100) * MaxLoadFactor100; + } + + ROBIN_HOOD(NODISCARD) size_t calcNumBytesInfo(size_t numElements) const noexcept { + // we add a uint64_t, which houses the sentinel (first byte) and padding so we can load + // 64bit types. + return numElements + sizeof(uint64_t); + } + + ROBIN_HOOD(NODISCARD) + size_t calcNumElementsWithBuffer(size_t numElements) const noexcept { + auto maxNumElementsAllowed = calcMaxNumElementsAllowed(numElements); + return numElements + (std::min)(maxNumElementsAllowed, (static_cast<size_t>(0xFF))); + } + + // calculation only allowed for 2^n values + ROBIN_HOOD(NODISCARD) size_t calcNumBytesTotal(size_t numElements) const { +#if ROBIN_HOOD(BITNESS) == 64 + return numElements * sizeof(Node) + calcNumBytesInfo(numElements); +#else + // make sure we're doing 64bit operations, so we are at least safe against 32bit overflows. + auto const ne = static_cast<uint64_t>(numElements); + auto const s = static_cast<uint64_t>(sizeof(Node)); + auto const infos = static_cast<uint64_t>(calcNumBytesInfo(numElements)); + + auto const total64 = ne * s + infos; + auto const total = static_cast<size_t>(total64); + + if (ROBIN_HOOD_UNLIKELY(static_cast<uint64_t>(total) != total64)) { + throwOverflowError(); + } + return total; +#endif + } + +private: + template <typename Q = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<!std::is_void<Q>::value, bool>::type has(const value_type& e) const { + ROBIN_HOOD_TRACE(this) + auto it = find(e.first); + return it != end() && it->second == e.second; + } + + template <typename Q = mapped_type> + ROBIN_HOOD(NODISCARD) + typename std::enable_if<std::is_void<Q>::value, bool>::type has(const value_type& e) const { + ROBIN_HOOD_TRACE(this) + return find(e) != end(); + } + + void reserve(size_t c, bool forceRehash) { + ROBIN_HOOD_TRACE(this) + auto const minElementsAllowed = (std::max)(c, mNumElements); + auto newSize = InitialNumElements; + while (calcMaxNumElementsAllowed(newSize) < minElementsAllowed && newSize != 0) { + newSize *= 2; + } + if (ROBIN_HOOD_UNLIKELY(newSize == 0)) { + throwOverflowError(); + } + + ROBIN_HOOD_LOG("newSize > mMask + 1: " << newSize << " > " << mMask << " + 1") + + // only actually do anything when the new size is bigger than the old one. This prevents to + // continuously allocate for each reserve() call. + if (forceRehash || newSize > mMask + 1) { + rehashPowerOfTwo(newSize, false); + } + } + + // reserves space for at least the specified number of elements. + // only works if numBuckets if power of two + // True on success, false otherwise + void rehashPowerOfTwo(size_t numBuckets, bool forceFree) { + ROBIN_HOOD_TRACE(this) + + Node* const oldKeyVals = mKeyVals; + uint8_t const* const oldInfo = mInfo; + + const size_t oldMaxElementsWithBuffer = calcNumElementsWithBuffer(mMask + 1); + + // resize operation: move stuff + initData(numBuckets); + if (oldMaxElementsWithBuffer > 1) { + for (size_t i = 0; i < oldMaxElementsWithBuffer; ++i) { + if (oldInfo[i] != 0) { + // might throw an exception, which is really bad since we are in the middle of + // moving stuff. + insert_move(std::move(oldKeyVals[i])); + // destroy the node but DON'T destroy the data. + oldKeyVals[i].~Node(); + } + } + + // this check is not necessary as it's guarded by the previous if, but it helps + // silence g++'s overeager "attempt to free a non-heap object 'map' + // [-Werror=free-nonheap-object]" warning. + if (oldKeyVals != reinterpret_cast_no_cast_align_warning<Node*>(&mMask)) { + // don't destroy old data: put it into the pool instead + if (forceFree) { + std::free(oldKeyVals); + } else { + DataPool::addOrFree(oldKeyVals, calcNumBytesTotal(oldMaxElementsWithBuffer)); + } + } + } + } + + ROBIN_HOOD(NOINLINE) void throwOverflowError() const { +#if ROBIN_HOOD(HAS_EXCEPTIONS) + throw std::overflow_error("robin_hood::map overflow"); +#else + abort(); +#endif + } + + template <typename OtherKey, typename... Args> + std::pair<iterator, bool> try_emplace_impl(OtherKey&& key, Args&&... args) { + ROBIN_HOOD_TRACE(this) + auto idxAndState = insertKeyPrepareEmptySpot(key); + switch (idxAndState.second) { + case InsertionState::key_found: + break; + + case InsertionState::new_node: + ::new (static_cast<void*>(&mKeyVals[idxAndState.first])) Node( + *this, std::piecewise_construct, std::forward_as_tuple(std::forward<OtherKey>(key)), + std::forward_as_tuple(std::forward<Args>(args)...)); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = Node(*this, std::piecewise_construct, + std::forward_as_tuple(std::forward<OtherKey>(key)), + std::forward_as_tuple(std::forward<Args>(args)...)); + break; + + case InsertionState::overflow_error: + throwOverflowError(); + break; + } + + return std::make_pair(iterator(mKeyVals + idxAndState.first, mInfo + idxAndState.first), + InsertionState::key_found != idxAndState.second); + } + + template <typename OtherKey, typename Mapped> + std::pair<iterator, bool> insertOrAssignImpl(OtherKey&& key, Mapped&& obj) { + ROBIN_HOOD_TRACE(this) + auto idxAndState = insertKeyPrepareEmptySpot(key); + switch (idxAndState.second) { + case InsertionState::key_found: + mKeyVals[idxAndState.first].getSecond() = std::forward<Mapped>(obj); + break; + + case InsertionState::new_node: + ::new (static_cast<void*>(&mKeyVals[idxAndState.first])) Node( + *this, std::piecewise_construct, std::forward_as_tuple(std::forward<OtherKey>(key)), + std::forward_as_tuple(std::forward<Mapped>(obj))); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = Node(*this, std::piecewise_construct, + std::forward_as_tuple(std::forward<OtherKey>(key)), + std::forward_as_tuple(std::forward<Mapped>(obj))); + break; + + case InsertionState::overflow_error: + throwOverflowError(); + break; + } + + return std::make_pair(iterator(mKeyVals + idxAndState.first, mInfo + idxAndState.first), + InsertionState::key_found != idxAndState.second); + } + + void initData(size_t max_elements) { + mNumElements = 0; + mMask = max_elements - 1; + mMaxNumElementsAllowed = calcMaxNumElementsAllowed(max_elements); + + auto const numElementsWithBuffer = calcNumElementsWithBuffer(max_elements); + + // malloc & zero mInfo. Faster than calloc everything. + auto const numBytesTotal = calcNumBytesTotal(numElementsWithBuffer); + ROBIN_HOOD_LOG("std::calloc " << numBytesTotal << " = calcNumBytesTotal(" + << numElementsWithBuffer << ")") + mKeyVals = reinterpret_cast<Node*>( + detail::assertNotNull<std::bad_alloc>(std::malloc(numBytesTotal))); + mInfo = reinterpret_cast<uint8_t*>(mKeyVals + numElementsWithBuffer); + std::memset(mInfo, 0, numBytesTotal - numElementsWithBuffer * sizeof(Node)); + + // set sentinel + mInfo[numElementsWithBuffer] = 1; + + mInfoInc = InitialInfoInc; + mInfoHashShift = InitialInfoHashShift; + } + + enum class InsertionState { overflow_error, key_found, new_node, overwrite_node }; + + // Finds key, and if not already present prepares a spot where to pot the key & value. + // This potentially shifts nodes out of the way, updates mInfo and number of inserted + // elements, so the only operation left to do is create/assign a new node at that spot. + template <typename OtherKey> + std::pair<size_t, InsertionState> insertKeyPrepareEmptySpot(OtherKey&& key) { + for (int i = 0; i < 256; ++i) { + size_t idx{}; + InfoType info{}; + keyToIdx(key, &idx, &info); + nextWhileLess(&info, &idx); + + // while we potentially have a match + while (info == mInfo[idx]) { + if (WKeyEqual::operator()(key, mKeyVals[idx].getFirst())) { + // key already exists, do NOT insert. + // see http://en.cppreference.com/w/cpp/container/unordered_map/insert + return std::make_pair(idx, InsertionState::key_found); + } + next(&info, &idx); + } + + // unlikely that this evaluates to true + if (ROBIN_HOOD_UNLIKELY(mNumElements >= mMaxNumElementsAllowed)) { + if (!increase_size()) { + return std::make_pair(size_t(0), InsertionState::overflow_error); + } + continue; + } + + // key not found, so we are now exactly where we want to insert it. + auto const insertion_idx = idx; + auto const insertion_info = info; + if (ROBIN_HOOD_UNLIKELY(insertion_info + mInfoInc > 0xFF)) { + mMaxNumElementsAllowed = 0; + } + + // find an empty spot + while (0 != mInfo[idx]) { + next(&info, &idx); + } + + if (idx != insertion_idx) { + shiftUp(idx, insertion_idx); + } + // put at empty spot + mInfo[insertion_idx] = static_cast<uint8_t>(insertion_info); + ++mNumElements; + return std::make_pair(insertion_idx, idx == insertion_idx + ? InsertionState::new_node + : InsertionState::overwrite_node); + } + + // enough attempts failed, so finally give up. + return std::make_pair(size_t(0), InsertionState::overflow_error); + } + + bool try_increase_info() { + ROBIN_HOOD_LOG("mInfoInc=" << mInfoInc << ", numElements=" << mNumElements + << ", maxNumElementsAllowed=" + << calcMaxNumElementsAllowed(mMask + 1)) + if (mInfoInc <= 2) { + // need to be > 2 so that shift works (otherwise undefined behavior!) + return false; + } + // we got space left, try to make info smaller + mInfoInc = static_cast<uint8_t>(mInfoInc >> 1U); + + // remove one bit of the hash, leaving more space for the distance info. + // This is extremely fast because we can operate on 8 bytes at once. + ++mInfoHashShift; + auto const numElementsWithBuffer = calcNumElementsWithBuffer(mMask + 1); + + for (size_t i = 0; i < numElementsWithBuffer; i += 8) { + auto val = unaligned_load<uint64_t>(mInfo + i); + val = (val >> 1U) & UINT64_C(0x7f7f7f7f7f7f7f7f); + std::memcpy(mInfo + i, &val, sizeof(val)); + } + // update sentinel, which might have been cleared out! + mInfo[numElementsWithBuffer] = 1; + + mMaxNumElementsAllowed = calcMaxNumElementsAllowed(mMask + 1); + return true; + } + + // True if resize was possible, false otherwise + bool increase_size() { + // nothing allocated yet? just allocate InitialNumElements + if (0 == mMask) { + initData(InitialNumElements); + return true; + } + + auto const maxNumElementsAllowed = calcMaxNumElementsAllowed(mMask + 1); + if (mNumElements < maxNumElementsAllowed && try_increase_info()) { + return true; + } + + ROBIN_HOOD_LOG("mNumElements=" << mNumElements << ", maxNumElementsAllowed=" + << maxNumElementsAllowed << ", load=" + << (static_cast<double>(mNumElements) * 100.0 / + (static_cast<double>(mMask) + 1))) + + if (mNumElements * 2 < calcMaxNumElementsAllowed(mMask + 1)) { + // we have to resize, even though there would still be plenty of space left! + // Try to rehash instead. Delete freed memory so we don't steadyily increase mem in case + // we have to rehash a few times + nextHashMultiplier(); + rehashPowerOfTwo(mMask + 1, true); + } else { + // we've reached the capacity of the map, so the hash seems to work nice. Keep using it. + rehashPowerOfTwo((mMask + 1) * 2, false); + } + return true; + } + + void nextHashMultiplier() { + // adding an *even* number, so that the multiplier will always stay odd. This is necessary + // so that the hash stays a mixing function (and thus doesn't have any information loss). + mHashMultiplier += UINT64_C(0xc4ceb9fe1a85ec54); + } + + void destroy() { + if (0 == mMask) { + // don't deallocate! + return; + } + + Destroyer<Self, IsFlat && std::is_trivially_destructible<Node>::value>{} + .nodesDoNotDeallocate(*this); + + // This protection against not deleting mMask shouldn't be needed as it's sufficiently + // protected with the 0==mMask check, but I have this anyways because g++ 7 otherwise + // reports a compile error: attempt to free a non-heap object 'fm' + // [-Werror=free-nonheap-object] + if (mKeyVals != reinterpret_cast_no_cast_align_warning<Node*>(&mMask)) { + ROBIN_HOOD_LOG("std::free") + std::free(mKeyVals); + } + } + + void init() noexcept { + mKeyVals = reinterpret_cast_no_cast_align_warning<Node*>(&mMask); + mInfo = reinterpret_cast<uint8_t*>(&mMask); + mNumElements = 0; + mMask = 0; + mMaxNumElementsAllowed = 0; + mInfoInc = InitialInfoInc; + mInfoHashShift = InitialInfoHashShift; + } + + // members are sorted so no padding occurs + uint64_t mHashMultiplier = UINT64_C(0xc4ceb9fe1a85ec53); // 8 byte 8 + Node* mKeyVals = reinterpret_cast_no_cast_align_warning<Node*>(&mMask); // 8 byte 16 + uint8_t* mInfo = reinterpret_cast<uint8_t*>(&mMask); // 8 byte 24 + size_t mNumElements = 0; // 8 byte 32 + size_t mMask = 0; // 8 byte 40 + size_t mMaxNumElementsAllowed = 0; // 8 byte 48 + InfoType mInfoInc = InitialInfoInc; // 4 byte 52 + InfoType mInfoHashShift = InitialInfoHashShift; // 4 byte 56 + // 16 byte 56 if NodeAllocator +}; + +} // namespace detail + +// map + +template <typename Key, typename T, typename Hash = hash<Key>, + typename KeyEqual = std::equal_to<Key>, size_t MaxLoadFactor100 = 80> +using unordered_flat_map = detail::Table<true, MaxLoadFactor100, Key, T, Hash, KeyEqual>; + +template <typename Key, typename T, typename Hash = hash<Key>, + typename KeyEqual = std::equal_to<Key>, size_t MaxLoadFactor100 = 80> +using unordered_node_map = detail::Table<false, MaxLoadFactor100, Key, T, Hash, KeyEqual>; + +template <typename Key, typename T, typename Hash = hash<Key>, + typename KeyEqual = std::equal_to<Key>, size_t MaxLoadFactor100 = 80> +using unordered_map = + detail::Table<sizeof(robin_hood::pair<Key, T>) <= sizeof(size_t) * 6 && + std::is_nothrow_move_constructible<robin_hood::pair<Key, T>>::value && + std::is_nothrow_move_assignable<robin_hood::pair<Key, T>>::value, + MaxLoadFactor100, Key, T, Hash, KeyEqual>; + +// set + +template <typename Key, typename Hash = hash<Key>, typename KeyEqual = std::equal_to<Key>, + size_t MaxLoadFactor100 = 80> +using unordered_flat_set = detail::Table<true, MaxLoadFactor100, Key, void, Hash, KeyEqual>; + +template <typename Key, typename Hash = hash<Key>, typename KeyEqual = std::equal_to<Key>, + size_t MaxLoadFactor100 = 80> +using unordered_node_set = detail::Table<false, MaxLoadFactor100, Key, void, Hash, KeyEqual>; + +template <typename Key, typename Hash = hash<Key>, typename KeyEqual = std::equal_to<Key>, + size_t MaxLoadFactor100 = 80> +using unordered_set = detail::Table<sizeof(Key) <= sizeof(size_t) * 6 && + std::is_nothrow_move_constructible<Key>::value && + std::is_nothrow_move_assignable<Key>::value, + MaxLoadFactor100, Key, void, Hash, KeyEqual>; + +} // namespace robin_hood + +#endif |