From fb2f57391a26207e8a6e0374cd72ff0cb61dbef0 Mon Sep 17 00:00:00 2001 From: Dominik Drexler Date: Sat, 21 Dec 2024 18:18:08 +0100 Subject: [PATCH] added robin hood hash, removed muted locks since we have to design it differently --- include/loki/details/utils/robin_hood.h | 2721 +++++++++++++++++ .../details/utils/segmented_repository.hpp | 36 +- include/loki/loki.hpp | 1 + 3 files changed, 2727 insertions(+), 31 deletions(-) create mode 100644 include/loki/details/utils/robin_hood.h diff --git a/include/loki/details/utils/robin_hood.h b/include/loki/details/utils/robin_hood.h new file mode 100644 index 00000000..36986be4 --- /dev/null +++ b/include/loki/details/utils/robin_hood.h @@ -0,0 +1,2721 @@ +// ______ _____ ______ _________ +// ______________ ___ /_ ___(_)_______ ___ /_ ______ ______ ______ / +// __ ___/_ __ \__ __ \__ / __ __ \ __ __ \_ __ \_ __ \_ __ / +// _ / / /_/ /_ /_/ /_ / _ / / / _ / / // /_/ // /_/ // /_/ / +// /_/ \____/ /_.___/ /_/ /_/ /_/ ________/_/ /_/ \____/ \____/ \__,_/ +// _/_____/ +// +// 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 . +// SPDX-License-Identifier: MIT +// Copyright (c) 2018-2021 Martin Ankerl +// +// 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 +#include +#include +#include +#include +#include // only to support hash of smart pointers +#include +#include +#include +#include +#if __cplusplus >= 201703L +#include +#endif + +// #define ROBIN_HOOD_LOG_ENABLED +#ifdef ROBIN_HOOD_LOG_ENABLED +#include +#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 +#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 +#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 +#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(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 && !defined(__clang__) +#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 +struct alignment_of : std::integral_constant::type)> +{ +}; + +template +class integer_sequence +{ +public: + using value_type = T; + static_assert(std::is_integral::value, "not integral type"); + static constexpr std::size_t size() noexcept { return sizeof...(Ints); } +}; +template +using index_sequence = integer_sequence; + +namespace detail_ +{ +template +struct IntSeqImpl +{ + using TValue = T; + static_assert(std::is_integral::value, "not integral type"); + static_assert(Begin >= 0 && Begin < End, "unexpected argument (Begin<0 || Begin<=End)"); + + template + struct IntSeqCombiner; + + template + struct IntSeqCombiner, integer_sequence> + { + using TResult = integer_sequence; + }; + + using TResult = typename IntSeqCombiner::TResult, + typename IntSeqImpl::TResult>::TResult; +}; + +template +struct IntSeqImpl +{ + using TValue = T; + static_assert(std::is_integral::value, "not integral type"); + static_assert(Begin >= 0, "unexpected argument (Begin<0)"); + using TResult = integer_sequence; +}; + +template +struct IntSeqImpl +{ + using TValue = T; + static_assert(std::is_integral::value, "not integral type"); + static_assert(Begin >= 0, "unexpected argument (Begin<0)"); + using TResult = integer_sequence; +}; +} // namespace detail_ + +template +using make_integer_sequence = typename detail_::IntSeqImpl::TResult; + +template +using make_index_sequence = make_integer_sequence; + +template +using index_sequence_for = make_index_sequence; + +} // 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 +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 +inline T reinterpret_cast_no_cast_align_warning(void* ptr) noexcept +{ + return reinterpret_cast(ptr); +} + +template +inline T reinterpret_cast_no_cast_align_warning(void const* ptr) noexcept +{ + return reinterpret_cast(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 +[[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)...); +} +#else + void doThrow(Args&&... ROBIN_HOOD_UNUSED(args) /*unused*/) +{ + abort(); +} +#endif + +template +T* assertNotNull(T* t, Args&&... args) +{ + if (ROBIN_HOOD_UNLIKELY(nullptr == t)) + { + doThrow(std::forward(args)...); + } + return t; +} + +template +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 +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(tmp); + } + mHead = nullptr; + } + + // allocates, but does NOT initialize. Use in-place new constructor, e.g. + // T* obj = pool.allocate(); + // ::new (static_cast(obj)) T(); + T* allocate() + { + T* tmp = mHead; + if (!tmp) + { + tmp = performAllocation(); + } + + mHead = *reinterpret_cast_no_cast_align_warning(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(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& 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(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(ptr); + + // link free list + auto x = reinterpret_cast(data); + *x = mListForFree; + mListForFree = data; + + // create linked list for newly allocated data + auto* const headT = reinterpret_cast_no_cast_align_warning(reinterpret_cast(ptr) + ALIGNMENT); + + auto* const head = reinterpret_cast(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(head + i * ALIGNED_SIZE) = head + (i + 1) * ALIGNED_SIZE; + } + + // last one points to 0 + *reinterpret_cast_no_cast_align_warning(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::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::value, std::alignment_of::value); +#else + static const size_t ALIGNMENT = (ROBIN_HOOD_STD::alignment_of::value > ROBIN_HOOD_STD::alignment_of::value) ? + ROBIN_HOOD_STD::alignment_of::value : + +ROBIN_HOOD_STD::alignment_of::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 +struct NodeAllocator; + +// dummy allocator that does nothing +template +struct NodeAllocator +{ + // 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 +struct NodeAllocator : public BulkPoolAllocator +{ +}; + +// 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 +struct nothrow +{ + static const bool value = noexcept(swap(std::declval(), std::declval())); +}; +#else +template +struct nothrow +{ + static const bool value = std::is_nothrow_swappable::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 +struct pair +{ + using first_type = T1; + using second_type = T2; + + template::value && std::is_default_constructible::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 const& o) noexcept(noexcept(T1(std::declval())) && noexcept(T2(std::declval()))) : + 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&& o) noexcept(noexcept(T1(std::move(std::declval()))) && noexcept(T2(std::move(std::declval())))) : + first(std::move(o.first)), + second(std::move(o.second)) + { + } + + constexpr pair(T1&& a, T2&& b) noexcept(noexcept(T1(std::move(std::declval()))) && noexcept(T2(std::move(std::declval())))) : + first(std::move(a)), + second(std::move(b)) + { + } + + template + constexpr pair(U1&& a, U2&& b) noexcept(noexcept(T1(std::forward(std::declval()))) && noexcept(T2(std::forward(std::declval())))) : + first(std::forward(a)), + second(std::forward(b)) + { + } + + template + // 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 a, + std::tuple b) noexcept(noexcept(pair(std::declval&>(), + std::declval&>(), + ROBIN_HOOD_STD::index_sequence_for(), + ROBIN_HOOD_STD::index_sequence_for()))) : + pair(a, b, ROBIN_HOOD_STD::index_sequence_for(), ROBIN_HOOD_STD::index_sequence_for()) + { + } + + // constructor called from the std::piecewise_construct_t ctor + template + pair(std::tuple& a, + std::tuple& b, + ROBIN_HOOD_STD::index_sequence /*unused*/, + ROBIN_HOOD_STD::index_sequence /*unused*/) noexcept(noexcept(T1(std::forward(std::get(std::declval&>()))...)) + && noexcept(T2(std::forward(std::get(std::declval&>()))...))) : + first(std::forward(std::get(a))...), + second(std::forward(std::get(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& o) noexcept((detail::swappable::nothrow::value) && (detail::swappable::nothrow::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 +inline void swap(pair& a, pair& b) noexcept(noexcept(std::declval&>().swap(std::declval&>()))) +{ + a.swap(b); +} + +template +inline constexpr bool operator==(pair const& x, pair const& y) +{ + return (x.first == y.first) && (x.second == y.second); +} +template +inline constexpr bool operator!=(pair const& x, pair const& y) +{ + return !(x == y); +} +template +inline constexpr bool operator<(pair const& x, pair const& y) noexcept(noexcept(std::declval() < std::declval()) + && noexcept(std::declval() < std::declval())) +{ + return x.first < y.first || (!(y.first < x.first) && x.second < y.second); +} +template +inline constexpr bool operator>(pair const& x, pair const& y) +{ + return y < x; +} +template +inline constexpr bool operator<=(pair const& x, pair const& y) +{ + return !(x > y); +} +template +inline constexpr bool operator>=(pair const& x, pair 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(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(data64 + i); + + k *= m; + k ^= k >> r; + k *= m; + + h ^= k; + h *= m; + } + + auto const* const data8 = reinterpret_cast(data64 + n_blocks); + switch (len & 7U) + { + case 7: + h ^= static_cast(data8[6]) << 48U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 6: + h ^= static_cast(data8[5]) << 40U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 5: + h ^= static_cast(data8[4]) << 32U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 4: + h ^= static_cast(data8[3]) << 24U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 3: + h ^= static_cast(data8[2]) << 16U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 2: + h ^= static_cast(data8[1]) << 8U; + ROBIN_HOOD(FALLTHROUGH); // FALLTHROUGH + case 1: + h ^= static_cast(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(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(x); +} + +// A thin wrapper around std::hash, performing an additional simple mixing step of the result. +template +struct hash : public std::hash +{ + size_t operator()(T const& obj) const noexcept(noexcept(std::declval>().operator()(std::declval()))) + { + // call base hash + auto result = std::hash::operator()(obj); + // return mixed of that, to be save against identity has + return hash_int(static_cast(result)); + } +}; + +template +struct hash> +{ + size_t operator()(std::basic_string const& str) const noexcept { return hash_bytes(str.data(), sizeof(CharT) * str.size()); } +}; + +#if ROBIN_HOOD(CXX) >= ROBIN_HOOD(CXX17) +template +struct hash> +{ + size_t operator()(std::basic_string_view const& sv) const noexcept { return hash_bytes(sv.data(), sizeof(CharT) * sv.size()); } +}; +#endif + +template +struct hash +{ + size_t operator()(T* ptr) const noexcept { return hash_int(reinterpret_cast(ptr)); } +}; + +template +struct hash> +{ + size_t operator()(std::unique_ptr const& ptr) const noexcept { return hash_int(reinterpret_cast(ptr.get())); } +}; + +template +struct hash> +{ + size_t operator()(std::shared_ptr const& ptr) const noexcept { return hash_int(reinterpret_cast(ptr.get())); } +}; + +template +struct hash::value>::type> +{ + size_t operator()(Enum e) const noexcept + { + using Underlying = typename std::underlying_type::type; + return hash {}(static_cast(e)); + } +}; + +#define ROBIN_HOOD_HASH_INT(T) \ + template<> \ + struct hash \ + { \ + size_t operator()(T const& obj) const noexcept { return hash_int(static_cast(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 +struct void_type +{ + using type = void; +}; + +template +struct has_is_transparent : public std::false_type +{ +}; + +template +struct has_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 +struct WrapHash : public T +{ + WrapHash() = default; + explicit WrapHash(T const& o) noexcept(noexcept(T(std::declval()))) : T(o) {} +}; + +template +struct WrapKeyEqual : public T +{ + WrapKeyEqual() = default; + explicit WrapKeyEqual(T const& o) noexcept(noexcept(T(std::declval()))) : 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 as member, +// or a DataNode with a pointer to std::pair. 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 +class Table : + public WrapHash, + public WrapKeyEqual, + detail::NodeAllocator< + typename std::conditional::value, Key, robin_hood::pair::type, T>>::type, + 4, + 16384, + IsFlat> +{ +public: + static constexpr bool is_flat = IsFlat; + static constexpr bool is_map = !std::is_void::value; + static constexpr bool is_set = !is_map; + static constexpr bool is_transparent = has_is_transparent::value && has_is_transparent::value; + + using key_type = Key; + using mapped_type = T; + using value_type = typename std::conditional::type, T>>::type; + using size_type = size_t; + using hasher = Hash; + using key_equal = KeyEqual; + using Self = Table; + +private: + static_assert(MaxLoadFactor100 > 10 && MaxLoadFactor100 < 100, "MaxLoadFactor100 needs to be >10 && < 100"); + + using WHash = WrapHash; + using WKeyEqual = WrapKeyEqual; + + // 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; + + // 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 + class DataNode + { + }; + + // Small: just allocate on the stack. + template + class DataNode final + { + public: + template + explicit DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, Args&&... args) noexcept(noexcept(value_type(std::forward(args)...))) : + mData(std::forward(args)...) + { + } + + DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, DataNode&& n) noexcept(std::is_nothrow_move_constructible::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 + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() noexcept + { + return mData.first; + } + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() noexcept + { + return mData; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() const noexcept + { + return mData.first; + } + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() const noexcept + { + return mData; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getSecond() noexcept + { + return mData.second; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getSecond() const noexcept + { + return mData.second; + } + + void swap(DataNode& o) noexcept(noexcept(std::declval().swap(std::declval()))) { mData.swap(o.mData); } + + private: + value_type mData; + }; + + // big object: allocate on heap. + template + class DataNode + { + public: + template + explicit DataNode(M& map, Args&&... args) : mData(map.allocate()) + { + ::new (static_cast(mData)) value_type(std::forward(args)...); + } + + DataNode(M& ROBIN_HOOD_UNUSED(map) /*unused*/, DataNode&& 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 + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() noexcept + { + return mData->first; + } + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() noexcept + { + return *mData; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() const noexcept + { + return mData->first; + } + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getFirst() const noexcept + { + return *mData; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getSecond() noexcept + { + return mData->second; + } + + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::type getSecond() const noexcept + { + return mData->second; + } + + void swap(DataNode& o) noexcept + { + using std::swap; + swap(mData, o.mData); + } + + private: + value_type* mData; + }; + + using Node = DataNode; + + // 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 + ROBIN_HOOD(NODISCARD) + typename std::enable_if::value, key_type const&>::type getFirstConst(value_type const& vt) const noexcept + { + return vt.first; + } + + // Cloner ////////////////////////////////////////////////////////// + + template + struct Cloner; + + // fast path: Just copy data, without allocating anything. + template + struct Cloner + { + void operator()(M const& source, M& target) const + { + auto const* const src = reinterpret_cast(source.mKeyVals); + auto* tgt = reinterpret_cast(target.mKeyVals); + auto const numElementsWithBuffer = target.calcNumElementsWithBuffer(target.mMask + 1); + std::copy(src, src + target.calcNumBytesTotal(numElementsWithBuffer), tgt); + } + }; + + template + struct Cloner + { + 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(t.mKeyVals + i)) Node(t, *s.mKeyVals[i]); + } + } + } + }; + + // Destroyer /////////////////////////////////////////////////////// + + template + struct Destroyer + { + }; + + template + struct Destroyer + { + void nodes(M& m) const noexcept { m.mNumElements = 0; } + + void nodesDoNotDeallocate(M& m) const noexcept { m.mNumElements = 0; } + }; + + template + struct Destroyer + { + 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 + // NOLINTNEXTLINE(hicpp-special-member-functions,cppcoreguidelines-special-member-functions) + class Iter + { + private: + using NodePtr = typename std::conditional::type; + + public: + using difference_type = std::ptrdiff_t; + using value_type = typename Self::value_type; + using reference = typename std::conditional::type; + using pointer = typename std::conditional::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::type> + // NOLINTNEXTLINE(hicpp-explicit-conversions) + Iter(Iter 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::type> + Iter& operator=(Iter 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 operator==(Iter const& o) const noexcept + { + return mKeyVals == o.mKeyVals; + } + + template + bool operator!=(Iter 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(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(mInfo))) + { + mInfo += 4; + mKeyVals += 4; + } + if (ROBIN_HOOD_UNLIKELY(0U == detail::unaligned_load(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; + 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 + 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(WHash::operator()(key)); + + h *= mHashMultiplier; + h ^= h >> 33U; + + // the lower InitialInfoNumBits are reserved for info. + *info = mInfoInc + static_cast((h & InfoMask) >> mInfoHashShift); + *idx = (static_cast(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::value) + { + auto idx = startIdx; + ::new (static_cast(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(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::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(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 + 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(std::distance(mKeyVals, reinterpret_cast_no_cast_align_warning(mInfo))); + } + + void cloneData(const Table& o) { Cloner()(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(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(&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; + using const_iterator = Iter; + + 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 + 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 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(o))), + WKeyEqual(std::move(static_cast(o))), + DataPool(std::move(static_cast(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(o))); + WKeyEqual::operator=(std::move(static_cast(o))); + DataPool::operator=(std::move(static_cast(o))); + + o.init(); + } + else + { + // nothing in the other map => just clear us. + clear(); + } + } + return *this; + } + + Table(const Table& o) : WHash(static_cast(o)), WKeyEqual(static_cast(o)), DataPool(static_cast(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(detail::assertNotNull(std::malloc(numBytesTotal))); + // no need for calloc because clonData does memcpy + mInfo = reinterpret_cast(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(o)); + WKeyEqual::operator=(static_cast(o)); + DataPool::operator=(static_cast(o)); + + return *this; + } + + // clean up old stuff + Destroyer::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(detail::assertNotNull(std::malloc(numBytesTotal))); + + // no need for calloc here because cloneData performs a memcpy. + mInfo = reinterpret_cast(mKeyVals + numElementsWithBuffer); + // sentinel is set in cloneData + } + WHash::operator=(static_cast(o)); + WKeyEqual::operator=(static_cast(o)); + DataPool::operator=(static_cast(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::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 std::enable_if::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(&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 std::enable_if::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(&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 + 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 ilist) + { + for (auto&& vt : ilist) + { + insert(std::move(vt)); + } + } + + template + std::pair emplace(Args&&... args) + { + ROBIN_HOOD_TRACE(this) + Node n { *this, std::forward(args)... }; + auto idxAndState = insertKeyPrepareEmptySpot(getFirstConst(n)); + switch (idxAndState.second) + { + case InsertionState::key_found: + n.destroy(*this); + break; + + case InsertionState::new_node: + ::new (static_cast(&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 + iterator emplace_hint(const_iterator position, Args&&... args) + { + (void) position; + return emplace(std::forward(args)...).first; + } + + template + std::pair try_emplace(const key_type& key, Args&&... args) + { + return try_emplace_impl(key, std::forward(args)...); + } + + template + std::pair try_emplace(key_type&& key, Args&&... args) + { + return try_emplace_impl(std::move(key), std::forward(args)...); + } + + template + iterator try_emplace(const_iterator hint, const key_type& key, Args&&... args) + { + (void) hint; + return try_emplace_impl(key, std::forward(args)...).first; + } + + template + iterator try_emplace(const_iterator hint, key_type&& key, Args&&... args) + { + (void) hint; + return try_emplace_impl(std::move(key), std::forward(args)...).first; + } + + template + std::pair insert_or_assign(const key_type& key, Mapped&& obj) + { + return insertOrAssignImpl(key, std::forward(obj)); + } + + template + std::pair insert_or_assign(key_type&& key, Mapped&& obj) + { + return insertOrAssignImpl(std::move(key), std::forward(obj)); + } + + template + iterator insert_or_assign(const_iterator hint, const key_type& key, Mapped&& obj) + { + (void) hint; + return insertOrAssignImpl(key, std::forward(obj)).first; + } + + template + iterator insert_or_assign(const_iterator hint, key_type&& key, Mapped&& obj) + { + (void) hint; + return insertOrAssignImpl(std::move(key), std::forward(obj)).first; + } + + std::pair 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 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(mInfo)) + { + return 1; + } + return 0; + } + + template + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if::type count(const OtherKey& key) const + { + ROBIN_HOOD_TRACE(this) + auto kv = mKeyVals + findIdx(key); + if (kv != reinterpret_cast_no_cast_align_warning(mInfo)) + { + return 1; + } + return 0; + } + + bool contains(const key_type& key) const + { // NOLINT(modernize-use-nodiscard) + return 1U == count(key); + } + + template + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if::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 + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if::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(mInfo)) + { + doThrow("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 + // NOLINTNEXTLINE(modernize-use-nodiscard) + typename std::enable_if::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(mInfo)) + { + doThrow("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 + 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 std::enable_if::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 + 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 std::enable_if::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(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(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(pos.mKeyVals), const_cast(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(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(-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(size()) / static_cast(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::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(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(numElements); + auto const s = static_cast(sizeof(Node)); + auto const infos = static_cast(calcNumBytesInfo(numElements)); + + auto const total64 = ne * s + infos; + auto const total = static_cast(total64); + + if (ROBIN_HOOD_UNLIKELY(static_cast(total) != total64)) + { + throwOverflowError(); + } + return total; +#endif + } + +private: + template + ROBIN_HOOD(NODISCARD) + typename std::enable_if::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 + ROBIN_HOOD(NODISCARD) + typename std::enable_if::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(&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 + std::pair 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(&mKeyVals[idxAndState.first])) Node(*this, + std::piecewise_construct, + std::forward_as_tuple(std::forward(key)), + std::forward_as_tuple(std::forward(args)...)); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = Node(*this, + std::piecewise_construct, + std::forward_as_tuple(std::forward(key)), + std::forward_as_tuple(std::forward(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 + std::pair 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(obj); + break; + + case InsertionState::new_node: + ::new (static_cast(&mKeyVals[idxAndState.first])) + Node(*this, std::piecewise_construct, std::forward_as_tuple(std::forward(key)), std::forward_as_tuple(std::forward(obj))); + break; + + case InsertionState::overwrite_node: + mKeyVals[idxAndState.first] = + Node(*this, std::piecewise_construct, std::forward_as_tuple(std::forward(key)), std::forward_as_tuple(std::forward(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(detail::assertNotNull(std::malloc(numBytesTotal))); + mInfo = reinterpret_cast(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 + std::pair 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(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(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(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(mNumElements) * 100.0 / (static_cast(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::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(&mMask)) + { + ROBIN_HOOD_LOG("std::free") + std::free(mKeyVals); + } + } + + void init() noexcept + { + mKeyVals = reinterpret_cast_no_cast_align_warning(&mMask); + mInfo = reinterpret_cast(&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(&mMask); // 8 byte 16 + uint8_t* mInfo = reinterpret_cast(&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 KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_flat_map = detail::Table; + +template, typename KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_node_map = detail::Table; + +template, typename KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_map = + detail::Table) <= sizeof(size_t) * 6 && std::is_nothrow_move_constructible>::value + && std::is_nothrow_move_assignable>::value, + MaxLoadFactor100, + Key, + T, + Hash, + KeyEqual>; + +// set + +template, typename KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_flat_set = detail::Table; + +template, typename KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_node_set = detail::Table; + +template, typename KeyEqual = std::equal_to, size_t MaxLoadFactor100 = 80> +using unordered_set = + detail::Table::value && std::is_nothrow_move_assignable::value, + MaxLoadFactor100, + Key, + void, + Hash, + KeyEqual>; + +} // namespace robin_hood + +#endif \ No newline at end of file diff --git a/include/loki/details/utils/segmented_repository.hpp b/include/loki/details/utils/segmented_repository.hpp index 88eb176f..5d638665 100644 --- a/include/loki/details/utils/segmented_repository.hpp +++ b/include/loki/details/utils/segmented_repository.hpp @@ -20,8 +20,9 @@ #include "loki/details/utils/segmented_vector.hpp" +#include "loki/details/utils/robin_hood.h" + #include -#include #include #include #include @@ -41,14 +42,11 @@ class SegmentedRepository { private: // We use an unordered_set to test for uniqueness. - std::unordered_set m_uniqueness_set; + robin_hood::unordered_set m_uniqueness_set; // We use pre-allocated memory to store objects persistent. SegmentedVector m_persistent_vector; - // Mutex for synchronizing write operations - mutable std::shared_mutex m_mutex; - void range_check(size_t pos) const { if (pos >= size()) @@ -65,33 +63,13 @@ class SegmentedRepository } SegmentedRepository(const SegmentedRepository& other) = delete; SegmentedRepository& operator=(const SegmentedRepository& other) = delete; - SegmentedRepository(SegmentedRepository&& other) noexcept : - m_uniqueness_set(std::move(other.m_uniqueness_set)), - m_persistent_vector(std::move(other.m_persistent_vector)), - m_mutex() // Create a new mutex for the moved object - { - } - - SegmentedRepository& operator=(SegmentedRepository&& other) noexcept - { - if (this != &other) - { - std::unique_lock lock_this(m_mutex, std::defer_lock); - std::unique_lock lock_other(other.m_mutex, std::defer_lock); - std::lock(lock_this, lock_other); - - m_uniqueness_set = std::move(other.m_uniqueness_set); - m_persistent_vector = std::move(other.m_persistent_vector); - } - return *this; - } + SegmentedRepository(SegmentedRepository&& other) = default; + SegmentedRepository& operator=(SegmentedRepository&& other) = default; /// @brief Returns a pointer to an existing object or creates it before if it does not exist. template T const* get_or_create(Args&&... args) { - std::unique_lock lock(m_mutex); // Lock only for writing - /* Construct and insert the element in persistent memory. */ // Ensure that element with identifier i is stored at position i. @@ -147,19 +125,16 @@ class SegmentedRepository auto begin() const { - std::shared_lock lock(m_mutex); return m_persistent_vector.begin(); } auto end() const { - std::shared_lock lock(m_mutex); return m_persistent_vector.end(); } const SegmentedVector& get_storage() const { - std::shared_lock lock(m_mutex); return m_persistent_vector; } @@ -169,7 +144,6 @@ class SegmentedRepository size_t size() const { - std::shared_lock lock(m_mutex); return m_persistent_vector.size(); } }; diff --git a/include/loki/loki.hpp b/include/loki/loki.hpp index 5cc3d420..883943be 100644 --- a/include/loki/loki.hpp +++ b/include/loki/loki.hpp @@ -61,5 +61,6 @@ #include "loki/details/utils/memory.hpp" #include "loki/details/utils/segmented_repository.hpp" #include "loki/details/utils/segmented_vector.hpp" +#include "loki/details/utils/robin_hood.h" #endif