This implements the part of P2210R2 "Superior String Splitting" that
resolves LWG 3478 for split_view (now named lazy_split_view).
libstdc++-v3/ChangeLog:
* include/std/ranges (lazy_split_view::_OuterIter::__at_end):
Check _M_trailing_empty.
(lazy_split_view::_OuterIter::_M_trailing_empty): Define this
data member.
(lazy_split_view::_OuterIter::operator++): Set _M_trailing_empty
appropriately.
(lazy_split_view::_OuterIter::operator==): Compare
_M_trailing_empty.
* testsuite/std/ranges/adaptors/100479.cc (test03): Expect two
split parts instead of one.
* testsuite/std/ranges/adaptors/lazy_split.cc (test11): New test.
---
libstdc++-v3/include/std/ranges | 21 +++++++++++++++----
.../testsuite/std/ranges/adaptors/100479.cc | 6 +++---
.../std/ranges/adaptors/lazy_split.cc | 15 +++++++++++++
3 files changed, 35 insertions(+), 7 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index cc1ef112ff1..78562924bee 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -2879,7 +2879,7 @@ namespace views::__adaptor
constexpr bool
__at_end() const
- { return __current() == ranges::end(_M_parent->_M_base); }
+ { return __current() == ranges::end(_M_parent->_M_base) &&
!_M_trailing_empty; }
// [range.lazy.split.outer] p1
// Many of the following specifications refer to the notional member
@@ -2909,6 +2909,7 @@ namespace views::__adaptor
[[no_unique_address]]
__detail::__maybe_present_t<forward_range<_Vp>,
iterator_t<_Base>> _M_current;
+ bool _M_trailing_empty = false;
public:
using iterator_concept = conditional_t<forward_range<_Base>,
@@ -2977,7 +2978,10 @@ namespace views::__adaptor
// 3505. lazy_split_view::outer-iterator::operator++ misspecified
const auto __end = ranges::end(_M_parent->_M_base);
if (__current() == __end)
- return *this;
+ {
+ _M_trailing_empty = false;
+ return *this;
+ }
const auto [__pbegin, __pend] = subrange{_M_parent->_M_pattern};
if (__pbegin == __pend)
++__current();
@@ -2986,7 +2990,11 @@ namespace views::__adaptor
__current() = ranges::find(std::move(__current()), __end,
*__pbegin);
if (__current() != __end)
- ++__current();
+ {
+ ++__current();
+ if (__current() == __end)
+ _M_trailing_empty = true;
+ }
}
else
do
@@ -2996,6 +3004,8 @@ namespace views::__adaptor
if (__p == __pend)
{
__current() = __b;
+ if (__current() == __end)
+ _M_trailing_empty = true;
break;
}
} while (++__current() != __end);
@@ -3018,7 +3028,10 @@ namespace views::__adaptor
friend constexpr bool
operator==(const _OuterIter& __x, const _OuterIter& __y)
requires forward_range<_Base>
- { return __x._M_current == __y._M_current; }
+ {
+ return __x._M_current == __y._M_current
+ && __x._M_trailing_empty == __y._M_trailing_empty;
+ }
friend constexpr bool
operator==(const _OuterIter& __x, default_sentinel_t)
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/100479.cc
b/libstdc++-v3/testsuite/std/ranges/adaptors/100479.cc
index 9899ff92c0b..b8c1e6f4f57 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/100479.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/100479.cc
@@ -95,11 +95,11 @@ test03()
| views::drop_while([](auto) { return false; })
| views::filter([](auto) { return true; });
static_assert(ranges::forward_range<decltype(v)>);
- VERIFY( ranges::next(v.begin()) == v.end() );
+ VERIFY( ranges::distance(v) == 2 );
auto w = v;
- VERIFY( ranges::next(w.begin()) == w.end() );
+ VERIFY( ranges::distance(v) == 2 );
auto z = std::move(w);
- VERIFY( ranges::next(z.begin()) == z.end() );
+ VERIFY( ranges::distance(v) == 2 );
return true;
}
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc
b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc
index 12844525d86..133e9a7025b 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc
@@ -193,6 +193,20 @@ test10()
VERIFY( ranges::equal(v, (std::string_view[]){"x", "x"}) );
}
+void
+test11()
+{
+ // LWG 3478
+ static_assert(ranges::distance(views::lazy_split("text"sv, "text"sv)) == 2);
+ static_assert(ranges::distance(views::lazy_split(" text "sv, ' ')) == 3);
+ static_assert(ranges::distance(views::lazy_split(" t e x t "sv, ' ')) == 6);
+ static_assert(ranges::distance(views::lazy_split(" text "sv, " "sv)) ==
3);
+ static_assert(ranges::distance(views::lazy_split(" text "sv, " "sv)) ==
4);
+ static_assert(ranges::distance(views::lazy_split(" text "sv, " "sv))
== 4);
+ static_assert(ranges::distance(views::lazy_split("t"sv, 't')) == 2);
+ static_assert(ranges::distance(views::lazy_split("text"sv, ""sv)) == 4);
+}
+
int
main()
{
@@ -206,4 +220,5 @@ main()
test08();
test09();
test10();
+ test11();
}
--
2.32.0.93.g670b81a890
