feedc0de/boost_unordered
1
0
Fork 0
forked from boostorg/unordered
Code Pull Requests Activity

refactored bdfe294e61 and expanded to move assign and swap

Browse Source
This commit is contained in:
joaquintides
2022-10-04 11:24:21 +02:00
parent bdfe294e61
commit 06512a00e1
1 changed files with 46 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

70
include/boost/unordered/detail/foa.hpp
View File

@ -824,6 +824,32 @@ using table_arrays=typename std::conditional<
aligned_table_arrays<Value,Group,SizePolicy>,
subaligned_table_arrays<Value,Group,SizePolicy>>::type;
struct if_constexpr_void_else{void operator()()const{}};
template<bool B,typename F,typename G=if_constexpr_void_else>
void if_constexpr(F f,G g={})
{
std::get<B?0:1>(std::forward_as_tuple(f,g))();
}
template<bool B,typename T,typename std::enable_if<B>::type* =nullptr>
void copy_assign_if(T& x,const T& y){x=y;}
template<bool B,typename T,typename std::enable_if<!B>::type* =nullptr>
void copy_assign_if(T& x,const T& y){}
template<bool B,typename T,typename std::enable_if<B>::type* =nullptr>
void move_assign_if(T& x,T& y){x=std::move(y);}
template<bool B,typename T,typename std::enable_if<!B>::type* =nullptr>
void move_assign_if(T& x,T& y){}
template<bool B,typename T,typename std::enable_if<B>::type* =nullptr>
void swap_if(T& x,T& y){using std::swap; swap(x,y);}
template<bool B,typename T,typename std::enable_if<!B>::type* =nullptr>
void swap_if(T& x,T& y){}
#if defined(BOOST_GCC)
/* GCC's -Wshadow triggers at scenarios like this:
*
@ -975,31 +1001,19 @@ public:
delete_arrays(arrays);
}
template <class AllocTraits>
typename std::enable_if<
!AllocTraits::propagate_on_container_copy_assignment::value,
void
>::type
copy_assign_helper(const table&) {}
template <class AllocTraits>
typename std::enable_if<
AllocTraits::propagate_on_container_copy_assignment::value,
void
>::type
copy_assign_helper(const table& x)
{
if(al()!=x.al())reserve(0);
al()=x.al();
}
table& operator=(const table& x)
{
static constexpr auto pocca=
alloc_traits::propagate_on_container_copy_assignment::value;
if(this!=&x){
clear();
h()=x.h();
pred()=x.pred();
copy_assign_helper<alloc_traits>(x);
if_constexpr<pocca>([&,this]{
if(al()!=x.al())reserve(0);
copy_assign_if<pocca>(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){
@ -1020,9 +1034,10 @@ public:
std::is_nothrow_move_assignable<Hash>::value&&
std::is_nothrow_move_assignable<Pred>::value)
{
static constexpr auto pocma=
alloc_traits::propagate_on_container_move_assignment::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());
@ -1031,7 +1046,7 @@ public:
reserve(0);
swap(arrays,x.arrays);
swap(ml,x.ml);
if(pocma)al()=std::move(x.al());
move_assign_if<pocma>(al(),x.al());
}
else{
reserve(x.size());
@ -1136,11 +1151,18 @@ public:
boost::is_nothrow_swappable<Hash>::value&&
boost::is_nothrow_swappable<Pred>::value)
{
static constexpr auto pocs=
alloc_traits::propagate_on_container_swap::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());
if_constexpr<pocs>([&,this]{
swap_if<pocs>(al(),x.al());
},
[&,this]{ /* else */
BOOST_ASSERT(al()==x.al());
});
swap(size_,x.size_);
swap(arrays,x.arrays);
swap(ml,x.ml);