boostorg/container
1
0
Fork 1
mirror of https://github.com/boostorg/container.git synced 2026-07-06 16:20:48 +02:00
Code Issues Packages Projects Releases Wiki Activity

Optimize for fixed size range_sz

Browse Source
This commit is contained in:
Ion Gaztañaga
2026-05-21 14:45:27 +02:00
parent 9d1fa77e4f
commit c67029c92a
1 changed files with 53 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/boost/container/experimental/segmented_fill_n.hpp
+53 -33
View File
@@ -34,14 +34,14 @@ namespace detail_algo {
template <class OutIter, class Size, class T>
BOOST_CONTAINER_FORCEINLINE
OutIter fill_n_scan
( OutIter first, OutIter last, Size& BOOST_RESTRICT count
segduo<OutIter, Size> fill_n_scan
( OutIter first, OutIter last, Size count
, const T& value, non_segmented_iterator_tag, const std::random_access_iterator_tag &)
{
std::size_t range_sz = static_cast<std::size_t>(last - first);
Size range_sz = static_cast<Size>(last - first);
#if defined(BOOST_CONTAINER_SEGMENTED_LOOP_UNROLLING)
const Size local_count = (std::size_t)count < range_sz ? count : (Size)range_sz;
#if defined(BOOST_CONTAINER_SEGMENTED_LOOP_UNROLLING)
Size cnt = local_count;
while(cnt >= Size(4)) {
*first = value; ++first;
@@ -64,34 +64,42 @@ OutIter fill_n_scan
default:
break;
}
return segduo<OutIter, Size>(first, count - local_count);
#else
BOOST_CONTAINER_SEGMENTED_UNROLL(4)
for(Size cnt = local_count; cnt; ++first, --cnt)
*first = value;
//If the whole range is fixed at compile time (e.g. deque)
//some compilers (e.g. MSVC 2026) can use SIMD more efficiently
//than when using count.
if (count >= range_sz) {
count -= range_sz;
BOOST_CONTAINER_SEGMENTED_UNROLL(4)
for (Size cnt = 0; cnt != range_sz; ++first, ++cnt){
*first = value;
}
return segduo<OutIter, Size>(first, count);
}
else {
BOOST_CONTAINER_SEGMENTED_UNROLL(4)
for (Size cnt = 0; cnt != count; ++first, ++cnt)
*first = value;
return segduo<OutIter, Size>(first, Size(0));
}
#endif
count -= local_count;
return first;
}
template <class OutIter, class Size, class T, class Cat>
BOOST_CONTAINER_FORCEINLINE
OutIter fill_n_scan
(OutIter first, OutIter last, Size& BOOST_RESTRICT count, const T& value, non_segmented_iterator_tag, const Cat &)
segduo<OutIter, Size> fill_n_scan
(OutIter first, OutIter last, Size count, const T& value, non_segmented_iterator_tag, const Cat &)
{
Size local_count = count;
BOOST_CONTAINER_SEGMENTED_UNROLL(4)
for (; local_count > 0 && first != last; ++first, --local_count)
for (; count > 0 && first != last; ++first, --count)
*first = value;
count = local_count;
return first;
return segduo<OutIter, Size>(first, count);
}
template <class SegIt, class Size, class T, class Cat>
SegIt fill_n_scan(SegIt first, SegIt last, Size& BOOST_RESTRICT count, const T& value, segmented_iterator_tag, const Cat &)
segduo<SegIt, Size> fill_n_scan(SegIt first, SegIt last, Size count, const T& value, segmented_iterator_tag, const Cat &)
{
typedef segmented_iterator_traits<SegIt> traits;
typedef typename traits::local_iterator local_iterator;
@@ -104,22 +112,24 @@ SegIt fill_n_scan(SegIt first, SegIt last, Size& BOOST_RESTRICT count, const T&
if(scur == slast) {
const local_iterator ll = traits::local(last);
const local_iterator r = (fill_n_scan)(traits::local(first), ll, count, value, is_local_seg_t(), local_cat_t());
return (r != ll) ? traits::compose(scur, r) : last;
const segduo<local_iterator, Size> r = (fill_n_scan)(traits::local(first), ll, count, value, is_local_seg_t(), local_cat_t());
return segduo<SegIt, Size>((r.first != ll) ? traits::compose(scur, r.first) : last, r.second);
}
else {
local_iterator r = fill_n_scan(traits::local(first), traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
segduo<local_iterator, Size> r = fill_n_scan(traits::local(first), traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
count = r.second;
if (!count)
return traits::compose(scur, r);
return segduo<SegIt, Size>(traits::compose(scur, r.first), count);
for (++scur; scur != slast; ++scur) {
r = fill_n_scan(traits::begin(scur), traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
count = r.second;
if (!count)
return traits::compose(scur, r);
return segduo<SegIt, Size>(traits::compose(scur, r.first), count);
}
const local_iterator ll = traits::local(last);
r = fill_n_scan(traits::begin(slast), ll, count, value, is_local_seg_t(), local_cat_t());
return (r != ll) ? traits::compose(scur, r) : last;
return segduo<SegIt, Size>((r.first != ll) ? traits::compose(scur, r.first) : last, r.second);
}
}
@@ -134,16 +144,26 @@ SegIter segmented_fill_n_ref
typedef typename iterator_traits<local_iterator>::iterator_category local_cat_t;
segment_iterator scur = traits::segment(first);
local_iterator lcur = traits::local(first);
local_iterator lcur;
while(1) {
lcur = fill_n_scan(lcur, traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
if(count == 0)
break;
++scur;
lcur = traits::begin(scur);
{
const segduo<local_iterator, Size> r = fill_n_scan(traits::local(first), traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
lcur = r.first;
count = r.second;
}
if (count) {
++scur;
while (1) {
const segduo<local_iterator, Size> r = fill_n_scan(traits::begin(scur), traits::end(scur), count, value, is_local_seg_t(), local_cat_t());
lcur = r.first;
count = r.second;
if (count == 0)
break;
++scur;
}
}
return traits::compose(scur, lcur);
}