bm2dnix/spicetools
1
0
Fork 0
Code Issues 1 Pull Requests Packages Projects Releases 1 Wiki Activity
spice2x_nix
spicetools/external/robin_hood.h

2531 lines
92 KiB
C++
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// ______ _____ ______ _________
// ______________ ___ /_ ___(_)_______ ___ /_ ______ ______ ______ /
// __ ___/_ __ \__ __ \__ / __ __ \ __ __ \_ __ \_ __ \_ __ /
// _ / / /_/ /_ /_/ /_ / _ / / / _ / / // /_/ // /_/ // /_/ /
// /_/ \____/ /_.___/ /_/ /_/ /_/ ________/_/ /_/ \____/ \____/ \__,_/
// _/_____/
//
// 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 2 // 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>
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>
std::pair<iterator, bool> try_emplace(const_iterator hint, const key_type& key,
Args&&... args) {
(void)hint;
return try_emplace_impl(key, std::forward<Args>(args)...);
}
template <typename... Args>
std::pair<iterator, bool> try_emplace(const_iterator hint, key_type&& key, Args&&... args) {
(void)hint;
return try_emplace_impl(std::move(key), std::forward<Args>(args)...);
}
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>
std::pair<iterator, bool> insert_or_assign(const_iterator hint, const key_type& key,
Mapped&& obj) {
(void)hint;
return insertOrAssignImpl(key, std::forward<Mapped>(obj));
}
template <typename Mapped>
std::pair<iterator, bool> insert_or_assign(const_iterator hint, key_type&& key, Mapped&& obj) {
(void)hint;
return insertOrAssignImpl(std::move(key), std::forward<Mapped>(obj));
}
std::pair<iterator, bool> insert(const value_type& keyval) {
ROBIN_HOOD_TRACE(this)
return emplace(keyval);
}
std::pair<iterator, bool> insert(value_type&& keyval) {
return emplace(std::move(keyval));
}
// 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);
// calloc also zeroes everything
auto const numBytesTotal = calcNumBytesTotal(numElementsWithBuffer);
ROBIN_HOOD_LOG("std::calloc " << numBytesTotal << " = calcNumBytesTotal("
<< numElementsWithBuffer << ")")
mKeyVals = reinterpret_cast<Node*>(
detail::assertNotNull<std::bad_alloc>(std::calloc(1, numBytesTotal)));
mInfo = reinterpret_cast<uint8_t*>(mKeyVals + numElementsWithBuffer);
// 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)))
nextHashMultiplier();
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
rehashPowerOfTwo(mMask + 1, true);
} else {
// Each resize use a different hash so we don't so easily overflow.
// Make sure we only have odd numbers, so that the multiplication is reversible!
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
Reference in New Issue View Git Blame Copy Permalink