Unrolled segmented_remove_copy

This commit is contained in:
Ion Gaztañaga
2026-03-29 17:52:42 +02:00
parent 8951e3eae2
commit c3c79053bb
@@ -21,6 +21,7 @@
#include <boost/container/detail/config_begin.hpp>
#include <boost/container/detail/workaround.hpp>
#include <boost/container/experimental/segmented_iterator_traits.hpp>
#include <boost/container/detail/iterator.hpp>
namespace boost {
namespace container {
@@ -30,11 +31,46 @@ OutIter segmented_remove_copy_if(InIter first, Sent last, OutIter result, Pred p
namespace detail_algo {
template <class InIter, class Sent, class OutIter, class Pred, class Tag>
#if defined(BOOST_CONTAINER_SEGMENTED_LOOP_UNROLLING)
template <class InIter, class OutIter, class Pred>
OutIter segmented_remove_copy_if_dispatch
(InIter first, InIter last, OutIter result, Pred pred, const non_segmented_iterator_tag &, const std::random_access_iterator_tag &)
{
typedef typename iterator_traits<InIter>::difference_type difference_type;
difference_type n = last - first;
while(n >= difference_type(4)) {
if(!pred(*first)) { *result = *first; ++result; } ++first;
if(!pred(*first)) { *result = *first; ++result; } ++first;
if(!pred(*first)) { *result = *first; ++result; } ++first;
if(!pred(*first)) { *result = *first; ++result; } ++first;
n -= 4;
}
switch (n % 4) {
case 3:
if(!pred(*first)) { *result = *first; ++result; } ++first;
BOOST_FALLTHROUGH;
case 2:
if(!pred(*first)) { *result = *first; ++result; } ++first;
BOOST_FALLTHROUGH;
case 1:
if (!pred(*first)) { *result = *first; ++result; } //No need to increment first since we're done after this.
BOOST_FALLTHROUGH;
default:
break;
}
return result;
}
#endif //BOOST_CONTAINER_SEGMENTED_LOOP_UNROLLING
template <class InIter, class Sent, class OutIter, class Pred, class Tag, class Cat>
typename algo_enable_if_c<
!Tag::value || is_sentinel<Sent, InIter>::value, OutIter>::type
segmented_remove_copy_if_dispatch
(InIter first, Sent last, OutIter result, Pred pred, Tag)
(InIter first, Sent last, OutIter result, Pred pred, Tag, Cat)
{
for(; first != last; ++first) {
if(!pred(*first)) {
@@ -45,9 +81,9 @@ segmented_remove_copy_if_dispatch
return result;
}
template <class SegIter, class OutIter, class Pred>
template <class SegIter, class OutIter, class Pred, class Cat>
OutIter segmented_remove_copy_if_dispatch
(SegIter first, SegIter last, OutIter result, Pred pred, segmented_iterator_tag)
(SegIter first, SegIter last, OutIter result, Pred pred, segmented_iterator_tag, Cat)
{
typedef segmented_iterator_traits<SegIter> traits;
typedef typename traits::local_iterator local_iterator;
@@ -58,15 +94,15 @@ OutIter segmented_remove_copy_if_dispatch
segment_iterator slast = traits::segment(last);
if(sfirst == slast) {
return (segmented_remove_copy_if_dispatch)(traits::local(first), traits::local(last), result, pred, is_local_seg_t());
return (segmented_remove_copy_if_dispatch)(traits::local(first), traits::local(last), result, pred, is_local_seg_t(), Cat());
}
else {
result = (segmented_remove_copy_if_dispatch)(traits::local(first), traits::end(sfirst), result, pred, is_local_seg_t());
result = (segmented_remove_copy_if_dispatch)(traits::local(first), traits::end(sfirst), result, pred, is_local_seg_t(), Cat());
for(++sfirst; sfirst != slast; ++sfirst)
result = (segmented_remove_copy_if_dispatch)(traits::begin(sfirst), traits::end(sfirst), result, pred, is_local_seg_t());
result = (segmented_remove_copy_if_dispatch)(traits::begin(sfirst), traits::end(sfirst), result, pred, is_local_seg_t(), Cat());
return (segmented_remove_copy_if_dispatch)(traits::begin(sfirst), traits::local(last), result, pred, is_local_seg_t());
return (segmented_remove_copy_if_dispatch)(traits::begin(sfirst), traits::local(last), result, pred, is_local_seg_t(), Cat());
}
}
@@ -81,7 +117,7 @@ OutIter segmented_remove_copy_if(InIter first, Sent last, OutIter result, Pred p
{
typedef segmented_iterator_traits<InIter> traits;
return detail_algo::segmented_remove_copy_if_dispatch
(first, last, result, pred, typename traits::is_segmented_iterator());
(first, last, result, pred, typename traits::is_segmented_iterator(), typename iterator_traits<InIter>::iterator_category());
}
} // namespace container