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refactored insert_type creation in emplace

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This commit is contained in:
joaquintides
2023-03-13 17:50:03 +01:00
committed by Christian Mazakas
parent 8010f506a6
commit 4ed301df97
2 changed files with 42 additions and 35 deletions
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55
include/boost/unordered/detail/foa/core.hpp
View File

@ -1049,14 +1049,45 @@ struct table_locator
struct try_emplace_args_t{};
template <class T>
union uninitialized_storage
template<typename TypePolicy,typename Allocator,typename... Args>
class alloc_cted_insert_type
{
T t_;
uninitialized_storage(){}
~uninitialized_storage(){}
using emplace_type=typename std::conditional<
std::is_constructible<typename TypePolicy::init_type,Args...>::value,
typename TypePolicy::init_type,
typename TypePolicy::value_type
>::type;
using insert_type=typename std::conditional<
std::is_constructible<typename TypePolicy::value_type,emplace_type>::value,
emplace_type,typename TypePolicy::element_type
>::type;
Allocator al;
alignas(insert_type) unsigned char storage[sizeof(insert_type)];
public:
alloc_cted_insert_type(const Allocator& al_,Args&&... args):al{al_}
{
TypePolicy::construct(al,data(),std::forward<Args>(args)...);
}
~alloc_cted_insert_type()
{
TypePolicy::destroy(al,data());
}
insert_type* data(){return reinterpret_cast<insert_type*>(&storage);}
insert_type& value(){return *data();}
};
template<typename TypePolicy,typename Allocator,typename... Args>
alloc_cted_insert_type<TypePolicy,Allocator,Args...>
alloc_make_insert_type(const Allocator& al,Args&&... args)
{
return {al,std::forward<Args>(args)...};
}
/* table_core. The TypePolicy template parameter is used to generate
* instantiations suitable for either maps or sets, and introduces non-standard
* init_type and element_type:
@ -1421,14 +1452,6 @@ public:
table_core& x;
};
template <class T>
struct destroy_on_exit
{
Allocator &a;
T *p;
~destroy_on_exit(){type_policy::destroy(a,p);};
};
Hash& h(){return hash_base::get();}
const Hash& h()const{return hash_base::get();}
Pred& pred(){return pred_base::get();}
@ -1752,10 +1775,10 @@ private:
* that average probe length won't increase unboundedly in repeated
* insert/erase cycles (drift).
*/
auto ov=group_type::maybe_caused_overflow(pc);
ml-=ov;
bool ofw=group_type::maybe_caused_overflow(pc);
group_type::reset(pc);
available+=!ov;
ml-=ofw;
available+=!ofw;
}
void recover_slot(group_type* pg,std::size_t pos)

22
include/boost/unordered/detail/foa/table.hpp
View File

@ -297,25 +297,9 @@ public:
template<typename... Args>
BOOST_FORCEINLINE std::pair<iterator,bool> emplace(Args&&... args)
{
using emplace_type=typename std::conditional<
std::is_constructible<init_type,Args...>::value,
init_type,
value_type
>::type;
using insert_type=typename std::conditional<
std::is_constructible<
value_type,emplace_type>::value,
emplace_type,element_type
>::type;
uninitialized_storage<insert_type> s;
auto *p=std::addressof(s.t_);
type_policy::construct(this->al(),p,std::forward<Args>(args)...);
typename super::template destroy_on_exit<insert_type> guard{this->al(),p};
return emplace_impl(type_policy::move(*p));
auto x=alloc_make_insert_type<type_policy>(
this->al(),std::forward<Args>(args)...);
return emplace_impl(type_policy::move(x.value()));
}
template<typename Key,typename... Args>