boostorg/container
1
0
Fork 1
mirror of https://github.com/boostorg/container.git synced 2026-08-04 01:04:15 +02:00
Code Issues Packages Projects Releases Wiki Activity

Simplify walking

Browse Source
This commit is contained in:
Ion Gaztañaga
2026-07-28 14:35:18 +02:00
parent bec5099d56
commit b506adfa88
1 changed files with 29 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/boost/container/experimental/segmented_reverse.hpp
+29 -62
View File
@@ -116,46 +116,36 @@ segduo<It, It> segmented_reverse_disjoint_ranges(It f, It f_end, It l_beg, It l,
segment_iterator fs = traits::segment(f);
const segment_iterator fs_end = traits::segment(f_end);
local_iterator fi = traits::local(f);
local_iterator fi_end = (fs == fs_end) ? traits::local(f_end) : traits::end(fs);
segment_iterator ls = traits::segment(l);
const segment_iterator ls_beg = traits::segment(l_beg);
local_iterator li = traits::local(l);
local_iterator li_beg = (ls == ls_beg) ? traits::local(l_beg) : traits::begin(ls);
//At least one of the two sides is guaranteed to be fully consumed after this loop
//since the ranges are guaranteed not to overlap
while (true) {
//Reverse the front and back segments recursively
segduo<local_iterator, local_iterator> r =
segmented_reverse_disjoint_ranges(fi, fi_end, li_beg, li, is_local_seg_t(), local_cat_t());
fi = r.first;
li = r.second;
const local_iterator fi_end = (fs == fs_end) ? traits::local(f_end) : traits::end(fs);
const local_iterator li_beg = (ls == ls_beg) ? traits::local(l_beg) : traits::begin(ls);
{
const segduo<local_iterator, local_iterator> r =
segmented_reverse_disjoint_ranges(fi, fi_end, li_beg, li, is_local_seg_t(), local_cat_t());
fi = r.first;
li = r.second;
}
//Independent advancement of forward and backward segments since ranges do not to overlap
//Check if the forward segment was fully consumed
if (fi == fi_end) {
//Check if there are no more segments to advance on the forward side, in which case we are done
if (fs == fs_end)
return segduo<It, It>(f_end, traits::compose(ls, li));
//Advance the forward segment
break;
++fs;
fi = traits::begin(fs);
fi_end = (fs == fs_end) ? traits::local(f_end) : traits::end(fs);
}
//Check if the backward segment was fully consumed
if (li == li_beg) {
//Check if there are no more segments to retreat on the backward side, in which case we are done
if (ls == ls_beg)
return segduo<It, It>(traits::compose(fs, fi), l_beg);
//Retreat the backward segment
break;
--ls;
li = traits::end(ls);
li_beg = (ls == ls_beg) ? traits::local(l_beg) : traits::begin(ls);
}
}
return segduo<It, It>(traits::compose(fs, fi), traits::compose(ls, li));
}
template <class SegIt, class Cat>
@@ -174,50 +164,27 @@ void segmented_reverse_dispatch(SegIt first, SegIt last, segmented_iterator_tag,
local_iterator f_loc = traits::local(first);
local_iterator l_loc = traits::local(last);
if (sf != sl) {
local_iterator f_end = traits::end(sf);
local_iterator l_beg = traits::begin(sl);
while (sf != sl) {
const local_iterator f_end = traits::end(sf);
const local_iterator l_beg = traits::begin(sl);
while (true) {
segduo<local_iterator, local_iterator> r =
segmented_reverse_disjoint_ranges(f_loc, f_end, l_beg, l_loc, is_local_seg_t(), local_cat_t());
f_loc = r.first;
l_loc = r.second;
const segduo<local_iterator, local_iterator> r =
segmented_reverse_disjoint_ranges(f_loc, f_end, l_beg, l_loc, is_local_seg_t(), local_cat_t());
f_loc = r.first;
l_loc = r.second;
//Check if the backward side reached the end of its segment
if (l_loc == l_beg) {
//If both sides reached the end of their respective segments
//advance the forward segment and retreat the backward segment
if (f_loc == f_end) {
++sf;
//If both segments were adjacent and we exhausted both, we are done
if (sf == sl)
return;
f_loc = traits::begin(sf);
f_end = traits::end(sf);
}
--sl;
if (sf == sl) {
l_loc = f_end;
break;
}
l_beg = traits::begin(sl);
l_loc = traits::end(sl);
}
else { //The forward side reached the end of its segment
++sf;
if (sf == sl) {
f_loc = l_beg;
break;
}
f_loc = traits::begin(sf);
f_end = traits::end(sf);
}
if (f_loc == f_end) {
++sf;
f_loc = traits::begin(sf);
if (sf == sl)
break;
}
if (l_loc == l_beg) {
--sl;
l_loc = traits::end(sl);
}
}
//Final reverse loop within the final segment
segmented_reverse_dispatch(f_loc, l_loc, is_local_seg_t(), local_cat_t());
}