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Initial commit of foa.hpp

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Christian Mazakas
2022-09-26 10:12:05 -07:00
parent 668abe4b0a
commit 7d69d18473
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include/boost/unordered/detail/foa.hpp Normal file
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/* Fast open-addressing hash table.
*
* Copyright 2022 Joaquin M Lopez Munoz.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See https://www.boost.org/libs/unordered for library home page.
*/
#ifndef BOOST_UNORDERED_DETAIL_FOA_HPP
#define BOOST_UNORDERED_DETAIL_FOA_HPP
#include <boost/assert.hpp>
#include <boost/config.hpp>
#include <boost/core/bit.hpp>
#include <boost/core/no_exceptions_support.hpp>
#include <boost/cstdint.hpp>
#include <boost/predef.h>
#include <boost/type_traits/is_nothrow_swappable.hpp>
#include <cstddef>
#include <cstring>
#include <climits>
#include <cmath>
#include <iterator>
#include <limits>
#include <memory>
#include <tuple>
#include <type_traits>
#include <utility>
#if defined(__SSE2__)||\
defined(_M_X64)||(defined(_M_IX86_FP)&&_M_IX86_FP>=2)
#define BOOST_UNORDERED_SSE2
#include <emmintrin.h>
#elif defined(__ARM_NEON)
#define BOOST_UNORDERED_NEON
#include <arm_neon.h>
#endif
#ifdef __has_builtin
#define BOOST_UNORDERED_HAS_BUILTIN(x) __has_builtin(x)
#else
#define BOOST_UNORDERED_HAS_BUILTIN(x) 0
#endif
#if !defined(NDEBUG)
#define BOOST_UNORDERED_ASSUME(cond) BOOST_ASSERT(cond)
#elif BOOST_UNORDERED_HAS_BUILTIN(__builtin_assume)
#define BOOST_UNORDERED_ASSUME(cond) __builtin_assume(cond)
#elif defined(__GNUC__) || BOOST_UNORDERED_HAS_BUILTIN(__builtin_unreachable)
#define BOOST_UNORDERED_ASSUME(cond) \
do{ \
if(!(cond))__builtin_unreachable(); \
}while(0)
#elif defined(_MSC_VER)
#define BOOST_UNORDERED_ASSUME(cond) __assume(cond)
#else
#define BOOST_UNORDERED_ASSUME(cond) \
do{ \
static_cast<void>(false&&(cond)); \
}while(0)
#endif
namespace boost{
namespace unordered{
namespace detail{
namespace foa{
/* TODO: description */
#ifdef BOOST_UNORDERED_SSE2
struct group15
{
static constexpr int N=15;
inline void set(std::size_t pos,std::size_t hash)
{
BOOST_ASSERT(pos<N);
at(pos)=adjust_hash(hash);
}
inline void set_sentinel()
{
at(N-1)=sentinel_;
}
inline bool is_sentinel(std::size_t pos)const
{
BOOST_ASSERT(pos<N);
return at(pos)==sentinel_;
}
inline void reset(std::size_t pos)
{
BOOST_ASSERT(pos<N);
at(pos)=available_;
}
static inline void reset(unsigned char* pc)
{
*pc=available_;
}
inline int match(std::size_t hash)const
{
return _mm_movemask_epi8(
_mm_cmpeq_epi8(m,_mm_set1_epi32(match_word(hash))))&0x7FFF;
}
inline bool is_not_overflowed(std::size_t hash)const
{
static constexpr unsigned char shift[]={1,2,4,8,16,32,64,128};
return !(overflow()&shift[hash%8]);
}
inline void mark_overflow(std::size_t hash)
{
overflow()|=1<<(hash%8);
}
inline int match_available()const
{
return _mm_movemask_epi8(
_mm_cmpeq_epi8(m,_mm_setzero_si128()))&0x7FFF;
}
inline int match_occupied()const
{
return (~match_available())&0x7FFF;
}
inline int match_really_occupied()const /* excluding sentinel */
{
return at(N-1)==sentinel_?match_occupied()&0x3FFF:match_occupied();
}
private:
static constexpr unsigned char available_=0,
sentinel_=1;
inline static int match_word(std::size_t hash)
{
static constexpr boost::uint32_t word[]=
{
0x02020202u,0x03030303u,0x02020202u,0x03030303u,0x04040404u,0x05050505u,0x06060606u,0x07070707u,
0x08080808u,0x09090909u,0x0A0A0A0Au,0x0B0B0B0Bu,0x0C0C0C0Cu,0x0D0D0D0Du,0x0E0E0E0Eu,0x0F0F0F0Fu,
0x10101010u,0x11111111u,0x12121212u,0x13131313u,0x14141414u,0x15151515u,0x16161616u,0x17171717u,
0x18181818u,0x19191919u,0x1A1A1A1Au,0x1B1B1B1Bu,0x1C1C1C1Cu,0x1D1D1D1Du,0x1E1E1E1Eu,0x1F1F1F1Fu,
0x20202020u,0x21212121u,0x22222222u,0x23232323u,0x24242424u,0x25252525u,0x26262626u,0x27272727u,
0x28282828u,0x29292929u,0x2A2A2A2Au,0x2B2B2B2Bu,0x2C2C2C2Cu,0x2D2D2D2Du,0x2E2E2E2Eu,0x2F2F2F2Fu,
0x30303030u,0x31313131u,0x32323232u,0x33333333u,0x34343434u,0x35353535u,0x36363636u,0x37373737u,
0x38383838u,0x39393939u,0x3A3A3A3Au,0x3B3B3B3Bu,0x3C3C3C3Cu,0x3D3D3D3Du,0x3E3E3E3Eu,0x3F3F3F3Fu,
0x40404040u,0x41414141u,0x42424242u,0x43434343u,0x44444444u,0x45454545u,0x46464646u,0x47474747u,
0x48484848u,0x49494949u,0x4A4A4A4Au,0x4B4B4B4Bu,0x4C4C4C4Cu,0x4D4D4D4Du,0x4E4E4E4Eu,0x4F4F4F4Fu,
0x50505050u,0x51515151u,0x52525252u,0x53535353u,0x54545454u,0x55555555u,0x56565656u,0x57575757u,
0x58585858u,0x59595959u,0x5A5A5A5Au,0x5B5B5B5Bu,0x5C5C5C5Cu,0x5D5D5D5Du,0x5E5E5E5Eu,0x5F5F5F5Fu,
0x60606060u,0x61616161u,0x62626262u,0x63636363u,0x64646464u,0x65656565u,0x66666666u,0x67676767u,
0x68686868u,0x69696969u,0x6A6A6A6Au,0x6B6B6B6Bu,0x6C6C6C6Cu,0x6D6D6D6Du,0x6E6E6E6Eu,0x6F6F6F6Fu,
0x70707070u,0x71717171u,0x72727272u,0x73737373u,0x74747474u,0x75757575u,0x76767676u,0x77777777u,
0x78787878u,0x79797979u,0x7A7A7A7Au,0x7B7B7B7Bu,0x7C7C7C7Cu,0x7D7D7D7Du,0x7E7E7E7Eu,0x7F7F7F7Fu,
0x80808080u,0x81818181u,0x82828282u,0x83838383u,0x84848484u,0x85858585u,0x86868686u,0x87878787u,
0x88888888u,0x89898989u,0x8A8A8A8Au,0x8B8B8B8Bu,0x8C8C8C8Cu,0x8D8D8D8Du,0x8E8E8E8Eu,0x8F8F8F8Fu,
0x90909090u,0x91919191u,0x92929292u,0x93939393u,0x94949494u,0x95959595u,0x96969696u,0x97979797u,
0x98989898u,0x99999999u,0x9A9A9A9Au,0x9B9B9B9Bu,0x9C9C9C9Cu,0x9D9D9D9Du,0x9E9E9E9Eu,0x9F9F9F9Fu,
0xA0A0A0A0u,0xA1A1A1A1u,0xA2A2A2A2u,0xA3A3A3A3u,0xA4A4A4A4u,0xA5A5A5A5u,0xA6A6A6A6u,0xA7A7A7A7u,
0xA8A8A8A8u,0xA9A9A9A9u,0xAAAAAAAAu,0xABABABABu,0xACACACACu,0xADADADADu,0xAEAEAEAEu,0xAFAFAFAFu,
0xB0B0B0B0u,0xB1B1B1B1u,0xB2B2B2B2u,0xB3B3B3B3u,0xB4B4B4B4u,0xB5B5B5B5u,0xB6B6B6B6u,0xB7B7B7B7u,
0xB8B8B8B8u,0xB9B9B9B9u,0xBABABABAu,0xBBBBBBBBu,0xBCBCBCBCu,0xBDBDBDBDu,0xBEBEBEBEu,0xBFBFBFBFu,
0xC0C0C0C0u,0xC1C1C1C1u,0xC2C2C2C2u,0xC3C3C3C3u,0xC4C4C4C4u,0xC5C5C5C5u,0xC6C6C6C6u,0xC7C7C7C7u,
0xC8C8C8C8u,0xC9C9C9C9u,0xCACACACAu,0xCBCBCBCBu,0xCCCCCCCCu,0xCDCDCDCDu,0xCECECECEu,0xCFCFCFCFu,
0xD0D0D0D0u,0xD1D1D1D1u,0xD2D2D2D2u,0xD3D3D3D3u,0xD4D4D4D4u,0xD5D5D5D5u,0xD6D6D6D6u,0xD7D7D7D7u,
0xD8D8D8D8u,0xD9D9D9D9u,0xDADADADAu,0xDBDBDBDBu,0xDCDCDCDCu,0xDDDDDDDDu,0xDEDEDEDEu,0xDFDFDFDFu,
0xE0E0E0E0u,0xE1E1E1E1u,0xE2E2E2E2u,0xE3E3E3E3u,0xE4E4E4E4u,0xE5E5E5E5u,0xE6E6E6E6u,0xE7E7E7E7u,
0xE8E8E8E8u,0xE9E9E9E9u,0xEAEAEAEAu,0xEBEBEBEBu,0xECECECECu,0xEDEDEDEDu,0xEEEEEEEEu,0xEFEFEFEFu,
0xF0F0F0F0u,0xF1F1F1F1u,0xF2F2F2F2u,0xF3F3F3F3u,0xF4F4F4F4u,0xF5F5F5F5u,0xF6F6F6F6u,0xF7F7F7F7u,
0xF8F8F8F8u,0xF9F9F9F9u,0xFAFAFAFAu,0xFBFBFBFBu,0xFCFCFCFCu,0xFDFDFDFDu,0xFEFEFEFEu,0xFFFFFFFFu,
};
return (int)word[(unsigned char)hash];
}
inline static unsigned char adjust_hash(std::size_t hash)
{
return (unsigned char)match_word(hash);
}
inline unsigned char& at(std::size_t pos)
{
return reinterpret_cast<unsigned char*>(&m)[pos];
}
inline unsigned char at(std::size_t pos)const
{
return reinterpret_cast<const unsigned char*>(&m)[pos];
}
inline unsigned char& overflow()
{
return at(N);
}
inline unsigned char overflow()const
{
return at(N);
}
__m128i m;
};
#endif
inline unsigned int unchecked_countr_zero(int x)
{
#if defined(BOOST_MSVC)
unsigned long r;
_BitScanForward(&r,(unsigned long)x);
return (unsigned int)r;
#else
BOOST_UNORDERED_ASSUME(x);
return (unsigned int)boost::core::countr_zero((unsigned int)x);
#endif
}
inline void prefetch(const void* p)
{
#if defined(BOOST_GCC)||defined(BOOST_CLANG)
__builtin_prefetch((const char*)p);
#elif defined(BOOST_UNORDERED_SSE2)
_mm_prefetch((const char*)p,_MM_HINT_T0);
#endif
}
struct pow2_size_policy
{
static inline std::size_t size_index(std::size_t n)
{
// TODO: min size is 2, see if we can bring it down to 1 without loss
// of performance
return sizeof(std::size_t)*CHAR_BIT-
(n<=2?1:((std::size_t)(boost::core::bit_width(n-1))));
}
static inline std::size_t size(std::size_t size_index)
{
return std::size_t(1)<<(sizeof(std::size_t)*CHAR_BIT-size_index);
}
static inline std::size_t position(std::size_t hash,std::size_t size_index)
{
return hash>>size_index;
}
};
struct pow2_quadratic_prober
{
pow2_quadratic_prober(std::size_t pos):pos{pos}{}
inline std::size_t get()const{return pos;}
inline bool next(std::size_t mask)
{
step+=1;
pos=(pos+step)&mask;
return step<=mask;
}
private:
std::size_t pos,step=0;
};
template<typename,typename,typename,typename>
class table;
template<typename Value,typename Group,bool Const>
class table_iterator
{
public:
using difference_type=std::ptrdiff_t;
using value_type=typename std::conditional<Const,const Value,Value>::type;
using pointer=value_type*;
using reference=value_type&;
using iterator_category=std::forward_iterator_tag;
table_iterator()=default;
template<bool Const2,typename std::enable_if<!Const2>::type* =nullptr>
table_iterator(const table_iterator<Value,Group,Const2>& x):
pc{x.pc},p{x.p}{}
inline reference operator*()const noexcept{return *p;}
inline pointer operator->()const noexcept{return p;}
inline table_iterator& operator++()noexcept{increment();return *this;}
inline table_iterator operator++(int)noexcept
{auto x=*this;increment();return x;}
friend inline bool operator==(
const table_iterator& x,const table_iterator& y)
{return x.p==y.p;}
friend inline bool operator!=(
const table_iterator& x,const table_iterator& y)
{return !(x==y);}
private:
template<typename,typename,bool> friend class table_iterator;
template<typename,typename,typename,typename> friend class table;
table_iterator(Group* pg,std::size_t n,const Value* p):
pc{reinterpret_cast<unsigned char*>(const_cast<Group*>(pg))+n},
p{const_cast<Value*>(p)}
{}
inline std::size_t rebase() noexcept
{
std::size_t off=reinterpret_cast<uintptr_t>(pc)%sizeof(Group);
pc-=off;
return off;
}
inline void increment()noexcept
{
std::size_t n0=rebase();
int mask=(reinterpret_cast<Group*>(pc)->match_occupied()>>(n0+1))<<(n0+1);
if(!mask){
do{
pc+=sizeof(Group);
p+=Group::N;
}
while(!(mask=reinterpret_cast<Group*>(pc)->match_occupied()));
}
auto n=unchecked_countr_zero(mask);
if(BOOST_UNLIKELY(reinterpret_cast<Group*>(pc)->is_sentinel(n))){
p=nullptr;
}
else{
pc+=n;
p+=n-n0;
}
}
unsigned char *pc=nullptr;
Value *p=nullptr;
};
template<typename TypePolicy,typename Hash,typename Pred,typename Allocator>
class table
{
using type_policy=TypePolicy;
using group_type=group15;
static constexpr auto N=group_type::N;
using size_policy=pow2_size_policy;
using prober=pow2_quadratic_prober;
public:
using key_type=typename type_policy::key_type;
using value_type=typename type_policy::value_type;
private:
static constexpr bool has_mutable_iterator=
!std::is_same<key_type,value_type>::value;
public:
using hasher=Hash;
using key_equal=Pred;
using allocator_type=Allocator;
using pointer=value_type*;
using const_pointer=const value_type*;
using reference=value_type&;
using const_reference=const value_type&;
using size_type=std::size_t;
using difference_type=std::ptrdiff_t;
using const_iterator=table_iterator<value_type,group_type,true>;
using iterator=typename std::conditional<
has_mutable_iterator,
table_iterator<value_type,group_type,false>,
const_iterator>::type;
table(
std::size_t n=0,const Hash& h=Hash(),const Pred& pred=Pred(),
const Allocator& al=Allocator()):
h{h},pred{pred},al{al},size_{0},arrays{new_arrays(n)},ml{max_load()}
{}
table(const table& x):table(x,x.al){}
table(table&& x)
noexcept(
std::is_nothrow_move_constructible<Hash>::value&&
std::is_nothrow_move_constructible<Pred>::value&&
std::is_nothrow_move_constructible<Allocator>::value):
// TODO verify if we should copy or move copy hash, pred and al
h{std::move(x.h)},pred{std::move(x.pred)},al{std::move(x.al)},
size_{x.size_},arrays{x.arrays},ml{x.ml}
{
x.size_=0;
x.arrays=x.new_arrays(0);
x.ml=x.max_load();
}
table(const table& x,const Allocator& al):
h{x.h},pred{x.pred},al{al},size_{0},
arrays{new_arrays(std::size_t(std::ceil(x.size()/mlf)))},
ml{max_load()}
{
BOOST_TRY{
x.for_all_elements([this](value_type* p){
unchecked_insert(*p);
});
}
BOOST_CATCH(...){
clear();
delete_arrays(arrays);
}
BOOST_CATCH_END
}
table(table&& x,const Allocator& al):
table{0,std::move(x.h),std::move(x.pred),al}
{
if(al==x.al){
size_=x.size_;
arrays=x.arrays;
ml=x.ml;
x.size_=0;
x.arrays=x.new_arrays(0);
x.ml=x.max_load();
}
else{
reserve(x.size());
BOOST_TRY{
/* This works because subsequent x.clear() does not depend on the
* elements' values.
*/
x.for_all_elements([this](value_type* p){
unchecked_insert(std::move(*p));
});
}
BOOST_CATCH(...){
clear();
delete_arrays(arrays);
x.clear();
}
BOOST_CATCH_END
x.clear();
}
}
~table()noexcept
{
clear();
delete_arrays(arrays);
}
table& operator=(const table& x)
{
if(this!=&x){
clear();
h=x.h;
pred=x.pred;
if(alloc_traits::propagate_on_container_copy_assignment::value){
if(al!=x.al)reserve(0);
al=x.al;
}
// TODO may shrink arrays and miss an opportunity for memory reuse
reserve(x.size());
x.for_all_elements([this](value_type* p){
unchecked_insert(*p);
});
}
return *this;
}
table& operator=(table&& x)
noexcept(
alloc_traits::is_always_equal::value&&
std::is_nothrow_move_assignable<Hash>::value&&
std::is_nothrow_move_assignable<Pred>::value)
{
if(this!=&x){
// TODO explain why not constexpr
auto pocma=alloc_traits::propagate_on_container_move_assignment::value;
clear();
h=std::move(x.h);
pred=std::move(x.pred);
if(pocma||al==x.al){
using std::swap;
reserve(0);
swap(arrays,x.arrays);
swap(ml,x.ml);
if(pocma)al=std::move(x.al);
}
else{
reserve(x.size());
BOOST_TRY{
/* This works because subsequent x.clear() does not depend on the
* elements' values.
*/
x.for_all_elements([this](value_type* p){
unchecked_insert(std::move(*p));
});
}
BOOST_CATCH(...){
x.clear();
}
BOOST_CATCH_END
x.clear();
}
}
return *this;
}
allocator_type get_allocator()const noexcept{return al;}
iterator begin()noexcept
{
iterator it{arrays.groups,0,arrays.elements};
if(!(arrays.groups[0].match_occupied()&0x1))++it;
return it;
}
const_iterator begin()const noexcept
{return const_cast<table*>(this)->begin();}
iterator end()noexcept{return {};}
const_iterator end()const noexcept{return const_cast<table*>(this)->end();}
const_iterator cbegin()const noexcept{return begin();}
const_iterator cend()const noexcept{return end();}
bool empty()const noexcept{return size()!=0;}
std::size_t size()const noexcept{return size_;}
std::size_t max_size()const noexcept{return SIZE_MAX;}
template<typename... Args>
BOOST_FORCEINLINE std::pair<iterator,bool> emplace(Args&&... args)
{
return emplace_impl(value_type(std::forward<Args>(args)...));
}
template<typename Key,typename... Args>
BOOST_FORCEINLINE std::pair<iterator,bool> try_emplace(
Key&& k,Args&&... args)
{
return emplace_impl(
std::piecewise_construct,
std::forward_as_tuple(std::forward<Key>(k)),
std::forward_as_tuple(std::forward<Args>(args)...));
}
BOOST_FORCEINLINE std::pair<iterator,bool> insert(const value_type& x)
{
return emplace_impl(x);
}
BOOST_FORCEINLINE std::pair<iterator,bool> insert(value_type&& x)
{
return emplace_impl(std::move(x));
}
template<
bool dependent_value=false,
typename std::enable_if<
has_mutable_iterator||dependent_value>::type* =nullptr
>
void erase(iterator pos)noexcept{return erase(const_iterator(pos));}
void erase(const_iterator pos)noexcept
{
destroy_element(pos.p);
group_type::reset(pos.pc);
--size_;
}
template<typename Key>
std::size_t erase(const Key& x)
{
auto it=find(x);
if(it!=end()){
erase(it);
return 1;
}
else return 0;
}
void swap(table& x)
noexcept(
alloc_traits::is_always_equal::value&&
boost::is_nothrow_swappable<Hash>::value&&
boost::is_nothrow_swappable<Pred>::value)
{
using std::swap;
swap(h,x.h);
swap(pred,x.pred);
if(alloc_traits::propagate_on_container_swap::value)swap(al,x.al);
else BOOST_ASSERT(al==x.al);
swap(size_,x.size_);
swap(arrays,x.arrays);
swap(ml,x.ml);
}
void clear()noexcept
{
for_all_elements([this](value_type* p){destroy_element(p);});
size_=0;
}
hasher hash_function()const{return h;}
key_equal key_eq()const{return pred;}
template<typename Key>
BOOST_FORCEINLINE iterator find(const Key& x)
{
auto hash=h(x);
return find_impl(x,position_for(hash),hash);
}
template<typename Key>
BOOST_FORCEINLINE const_iterator find(const Key& x)const
{
return const_cast<table*>(this)->find(x);
}
std::size_t capacity()const noexcept
{
return arrays.elements?(arrays.groups_size_mask+1)*N-1:0;
}
float load_factor()const noexcept{return float(size())/capacity();}
float max_load_factor()const noexcept{return mlf;}
void rehash(std::size_t n)
{
auto c1=std::size_t(std::ceil(float(size())/mlf));
auto c2=n?size_policy::size(size_policy::size_index(n/N+1))*N-1:0;
auto c=c1>c2?c1:c2; /* we avoid std::max to not include <algorithm> */
if(c!=capacity())unchecked_rehash(c);
}
void reserve(std::size_t n)
{
rehash(std::size_t(std::ceil(n/mlf)));
}
private:
using alloc_traits=std::allocator_traits<Allocator>;
using group_allocator=
typename alloc_traits::template rebind_alloc<group_type>;
using group_alloc_traits=std::allocator_traits<group_allocator>;
struct arrays_info{
std::size_t groups_size_index;
std::size_t groups_size_mask;
group_type *groups;
value_type *elements;
};
arrays_info new_arrays(std::size_t n)
{
auto groups_size_index=size_policy::size_index(n/N+1);
auto groups_size=size_policy::size(groups_size_index);
arrays_info new_arrays_{
groups_size_index,
groups_size-1,
nullptr,
nullptr
};
if(!n){
new_arrays_.groups=dummy_groups();
}
else{
group_allocator gal=al;
new_arrays_.groups=group_alloc_traits::allocate(gal,groups_size);
// TODO: explain why memset
std::memset(
new_arrays_.groups,0,sizeof(group_type)*groups_size-1);
new_arrays_.groups[groups_size-1].set_sentinel();
BOOST_TRY{
new_arrays_.elements=alloc_traits::allocate(al,groups_size*N-1);
}
BOOST_CATCH(...){
group_alloc_traits::deallocate(gal,new_arrays_.groups,groups_size);
BOOST_RETHROW;
}
BOOST_CATCH_END
}
return new_arrays_;
}
static group_type* dummy_groups()noexcept
{
#if defined(BOOST_UNORDERED_SSE2)
static_assert(
std::is_same<group_type,group15>::value,
"encapsulation breach"
);
alignas(group_type) static constexpr unsigned char
storage[sizeof(group_type)*2]={
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
};
return reinterpret_cast<group_type*>(const_cast<unsigned char*>(storage));
}
#else
#error encapsulation breach
#endif
void delete_arrays(const arrays_info& arrays_)noexcept
{
if(arrays_.elements){
auto groups_size=arrays_.groups_size_mask+1;
alloc_traits::deallocate(al,arrays_.elements,groups_size*N-1);
group_allocator gal=al;
group_alloc_traits::deallocate(gal,arrays_.groups,groups_size);
}
}
template<typename... Args>
void construct_element(value_type* p,Args&&... args)
{
alloc_traits::construct(al,p,std::forward<Args>(args)...);
}
void destroy_element(value_type* p)noexcept
{
alloc_traits::destroy(al,p);
}
std::size_t max_load()const
{
if(!arrays.elements){
return 0;
}
else {
float fml=mlf*(float)(capacity());
auto res=(std::numeric_limits<std::size_t>::max)();
if(res>fml)res=(std::size_t)fml;
return res;
}
}
static inline auto key_from(const value_type& x)
->decltype(type_policy::extract(x))
{
return type_policy::extract(x);
}
template<typename Key>
static inline const Key& key_from(const Key& x)
{
return x;
}
template<typename Arg1,typename Arg2>
static inline auto key_from(
std::piecewise_construct_t,const Arg1& k,const Arg2&)
->decltype(std::get<0>(k))
{
return std::get<0>(k);
}
inline std::size_t position_for(std::size_t hash)const
{
return position_for(hash,arrays);
}
static inline std::size_t position_for(
std::size_t hash,const arrays_info& arrays_)
{
return size_policy::position(hash,arrays_.groups_size_index);
}
static inline void prefetch_elements(const value_type* p)
{
#if BOOST_ARCH_ARM
constexpr int cache_line=64; // TODO: get from Boost.Predef?
// TODO: check if this is 128 in current benchmark machine
const char *p0=reinterpret_cast<const char*>(p),
*p1=p0+sizeof(value_type)*N/2;
for(auto p=p0;p<p1;p+=cache_line)prefetch(p);
#else
prefetch(p);
#endif
}
template<typename Key>
BOOST_FORCEINLINE iterator find_impl(
const Key& x,std::size_t pos0,std::size_t hash)const
{
prober pb(pos0);
do{
auto pos=pb.get();
auto pg=arrays.groups+pos;
auto mask=pg->match(hash);
if(mask){
auto p=arrays.elements+pos*N;
prefetch_elements(p);
do{
auto n=unchecked_countr_zero(mask);
if(BOOST_LIKELY(pred(x,key_from(p[n])))){
return {pg,n,p+n};
}
mask&=mask-1;
}while(mask);
}
if(BOOST_LIKELY(pg->is_not_overflowed(hash))){
return {}; // TODO end() does not work (returns const_iterator)
}
}
while(BOOST_LIKELY(pb.next(arrays.groups_size_mask)));
return {}; // TODO end() does not work (returns const_iterator)
}
template<typename... Args>
BOOST_FORCEINLINE std::pair<iterator,bool> emplace_impl(Args&&... args)
{
const auto &k=key_from(std::forward<Args>(args)...);
auto hash=h(k);
auto pos0=position_for(hash);
auto it=find_impl(k,pos0,hash);
if(it!=end()){
return {it,false};
}
else if(BOOST_UNLIKELY(size_>=ml)){
unchecked_rehash(capacity()+1); // TODO wrong if mlf is allowed to change
pos0=position_for(hash);
}
return {
unchecked_emplace_at(pos0,hash,std::forward<Args>(args)...),
true
};
}
BOOST_NOINLINE void unchecked_rehash(std::size_t n)
{
auto new_arrays_=new_arrays(n);
std::size_t num_tx=0;
BOOST_TRY{
for_all_elements([&,this](value_type* p){
nosize_transfer_element(p,new_arrays_);
++num_tx;
});
}
BOOST_CATCH(...){
size_-=num_tx;
if(num_tx){
auto pg=arrays.groups;
for(std::size_t pos=0;;++pos,++pg){
auto mask=pg->match_occupied();
while(mask){
auto n=unchecked_countr_zero(mask);
pg->reset(n);
if(!(--num_tx))goto continue_;
}
}
}
continue_:
for_all_elements(new_arrays_,[this](value_type* p){
destroy_element(p);
});
delete_arrays(new_arrays_);
BOOST_RETHROW;
}
BOOST_CATCH_END
delete_arrays(arrays);
arrays=new_arrays_;
ml=max_load();
}
template<typename Value>
void unchecked_insert(Value&& x)
{
auto hash=h(key_from(x));
unchecked_emplace_at(position_for(hash),hash,std::forward<Value>(x));
}
void nosize_transfer_element(value_type* p,const arrays_info& arrays_)
{
auto hash=h(key_from(*p));
nosize_unchecked_emplace_at(
arrays_,position_for(hash,arrays_),hash,std::move(*p));
destroy_element(p);
}
template<typename... Args>
iterator unchecked_emplace_at(
std::size_t pos0,std::size_t hash,Args&&... args)
{
auto res=nosize_unchecked_emplace_at(
arrays,pos0,hash,std::forward<Args>(args)...);
++size_;
return res;
}
#if 0
template<typename... Args>
iterator nosize_unchecked_emplace_at(
const arrays_info& arrays_,std::size_t pos0,std::size_t hash,
Args&&... args)
{
auto p=insert_position(arrays_,pos0,hash);
auto &pos=p.first;
auto &n=p.second;
auto pg=arrays_.groups+pos;
auto p=arrays_.elements+pos*N+n;
construct_element(p,std::forward<Args>(args)...);
pg->set(n,hash);
return {pg,n,p};
}
std::pair<std::size_t,std::size_t>
static insert_position(
const arrays_info& arrays_,std::size_t pos0,std::size_t hash)
{
for(prober pb(pos0);;pb.next(arrays_.groups_size_mask)){
auto pos=pb.get();
auto pg=arrays_.groups+pos;
auto mask=pg->match_available();
if(BOOST_LIKELY(mask)){
return {pos,unchecked_countr_zero(mask)};
}
else pg->mark_overflow(hash);
}
}
#else
template<typename... Args>
iterator nosize_unchecked_emplace_at(
const arrays_info& arrays_,std::size_t pos0,std::size_t hash,
Args&&... args)
{
for(prober pb(pos0);;pb.next(arrays_.groups_size_mask)){
auto pos=pb.get();
auto pg=arrays_.groups+pos;
auto mask=pg->match_available();
if(BOOST_LIKELY(mask)){
auto n=unchecked_countr_zero(mask);
auto p=arrays_.elements+pos*N+n;
construct_element(p,std::forward<Args>(args)...);
pg->set(n,hash);
return {pg,n,p};
}
else pg->mark_overflow(hash);
}
}
#endif
template<typename F>
void for_all_elements(F f)const
{
for_all_elements(arrays,f);
}
template<typename F>
static void for_all_elements(const arrays_info& arrays_,F f)
{
auto pg=arrays_.groups;
auto p=arrays_.elements;
for(std::size_t pos=0,last=arrays_.groups_size_mask+1;
pos!=last;++pos,++pg,p+=N){
auto mask=pg->match_really_occupied();
while(mask){
f(p+unchecked_countr_zero(mask));
mask&=mask-1;
}
}
}
Hash h;
Pred pred;
Allocator al;
static constexpr float mlf=0.875;
std::size_t size_;
arrays_info arrays;
std::size_t ml;
};
} /* namespace foa */
} /* namespace detail */
} /* namespace unordered */
} /* namespace boost */
#undef BOOST_UNORDERED_ASSUME
#undef BOOST_UNORDERED_HAS_BUILTIN
#ifdef BOOST_UNORDERED_NEON
#undef BOOST_UNORDERED_NEON
#endif
#ifdef BOOST_UNORDERED_SSE2
#undef BOOST_UNORDERED_SSE2
#endif
#endif