https://gcc.gnu.org/g:cfb20f17bd17e1cd98ccd8a4517ff3e925cf731c
commit r15-8010-gcfb20f17bd17e1cd98ccd8a4517ff3e925cf731c
Author: Patrick Palka <ppa...@redhat.com>
Date: Wed Mar 12 16:09:42 2025 -0400
libstdc++: Implement P3137R3 views::to_input for C++26
libstdc++-v3/ChangeLog:
* include/bits/version.def (ranges_to_input): Define.
* include/bits/version.h: Regenerate.
* include/std/ranges (ranges::to_input_view): Define for C++26.
(views::__detail::__can_to_input): Likewise.
(views::_ToInput, views::to_input): Likewise.
* testsuite/std/ranges/adaptors/to_input/1.cc: New test.
Reviewed-by: Tomasz Kamiński <tkami...@redhat.com>
Reviewed-by: Jonathan Wakely <jwak...@redhat.com>
Diff:
---
libstdc++-v3/include/bits/version.def | 8 +
libstdc++-v3/include/bits/version.h | 10 ++
libstdc++-v3/include/std/ranges | 170 +++++++++++++++++++++
.../testsuite/std/ranges/adaptors/to_input/1.cc | 59 +++++++
4 files changed, 247 insertions(+)
diff --git a/libstdc++-v3/include/bits/version.def
b/libstdc++-v3/include/bits/version.def
index 56638759539b..1468c0491b71 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1911,6 +1911,14 @@ ftms = {
};
};
+ftms = {
+ name = ranges_to_input;
+ values = {
+ v = 202502;
+ cxxmin = 26;
+ };
+};
+
ftms = {
name = to_string;
values = {
diff --git a/libstdc++-v3/include/bits/version.h
b/libstdc++-v3/include/bits/version.h
index 29e1535298cb..f7c9849893da 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -2120,6 +2120,16 @@
#endif /* !defined(__cpp_lib_text_encoding) &&
defined(__glibcxx_want_text_encoding) */
#undef __glibcxx_want_text_encoding
+#if !defined(__cpp_lib_ranges_to_input)
+# if (__cplusplus > 202302L)
+# define __glibcxx_ranges_to_input 202502L
+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_ranges_to_input)
+# define __cpp_lib_ranges_to_input 202502L
+# endif
+# endif
+#endif /* !defined(__cpp_lib_ranges_to_input) &&
defined(__glibcxx_want_ranges_to_input) */
+#undef __glibcxx_want_ranges_to_input
+
#if !defined(__cpp_lib_to_string)
# if (__cplusplus > 202302L) && _GLIBCXX_HOSTED && (__glibcxx_to_chars)
# define __glibcxx_to_string 202306L
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index e21f5284b46d..c2a2d6f4e05e 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -69,6 +69,7 @@
#define __glibcxx_want_ranges_slide
#define __glibcxx_want_ranges_stride
#define __glibcxx_want_ranges_to_container
+#define __glibcxx_want_ranges_to_input
#define __glibcxx_want_ranges_zip
#include <bits/version.h>
@@ -10390,6 +10391,175 @@ namespace ranges
} // namespace ranges
#endif // __cpp_lib_ranges_cache_latest
+#if __cpp_lib_ranges_to_input // C++ >= 26
+namespace ranges
+{
+ template<input_range _Vp>
+ requires view<_Vp>
+ class to_input_view : public view_interface<to_input_view<_Vp>>
+ {
+ _Vp _M_base = _Vp();
+
+ template<bool _Const>
+ class _Iterator;
+
+ public:
+ to_input_view() requires default_initializable<_Vp> = default;
+
+ constexpr explicit
+ to_input_view(_Vp __base)
+ : _M_base(std::move(__base))
+ { }
+
+ constexpr _Vp
+ base() const & requires copy_constructible<_Vp>
+ { return _M_base; }
+
+ constexpr _Vp
+ base() &&
+ { return std::move(_M_base); }
+
+ constexpr auto
+ begin() requires (!__detail::__simple_view<_Vp>)
+ { return _Iterator<false>(ranges::begin(_M_base)); }
+
+ constexpr auto
+ begin() const requires range<const _Vp>
+ { return _Iterator<true>(ranges::begin(_M_base)); }
+
+ constexpr auto
+ end() requires (!__detail::__simple_view<_Vp>)
+ { return ranges::end(_M_base); }
+
+ constexpr auto
+ end() const requires range<const _Vp>
+ { return ranges::end(_M_base); }
+
+ constexpr auto
+ size() requires sized_range<_Vp>
+ { return ranges::size(_M_base); }
+
+ constexpr auto
+ size() const requires sized_range<const _Vp>
+ { return ranges::size(_M_base); }
+ };
+
+ template<typename _Range>
+ to_input_view(_Range&&) -> to_input_view<views::all_t<_Range>>;
+
+ template<input_range _Vp>
+ requires view<_Vp>
+ template<bool _Const>
+ class to_input_view<_Vp>::_Iterator
+ {
+ using _Base = __maybe_const_t<_Const, _Vp>;
+
+ iterator_t<_Base> _M_current = iterator_t<_Base>();
+
+ constexpr explicit
+ _Iterator(iterator_t<_Base> __current)
+ : _M_current(std::move(__current))
+ { }
+
+ friend to_input_view;
+ friend _Iterator<!_Const>;
+
+ public:
+ using difference_type = range_difference_t<_Base>;
+ using value_type = range_value_t<_Base>;
+ using iterator_concept = input_iterator_tag;
+
+ _Iterator() requires default_initializable<iterator_t<_Base>> = default;
+
+ _Iterator(_Iterator&&) = default;
+ _Iterator& operator=(_Iterator&&) = default;
+
+ constexpr
+ _Iterator(_Iterator<!_Const> __i)
+ requires _Const && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
+ : _M_current(std::move(__i._M_current))
+ { }
+
+ constexpr iterator_t<_Base>
+ base() &&
+ { return std::move(_M_current); }
+
+ constexpr const iterator_t<_Base>&
+ base() const & noexcept
+ { return _M_current; }
+
+ constexpr decltype(auto)
+ operator*() const
+ { return *_M_current; }
+
+ constexpr _Iterator&
+ operator++()
+ {
+ ++_M_current;
+ return *this;
+ }
+
+ constexpr void
+ operator++(int)
+ { ++*this; }
+
+ friend constexpr bool
+ operator==(const _Iterator& __x, const sentinel_t<_Base>& __y)
+ { return __x._M_current == __y; }
+
+ friend constexpr difference_type
+ operator-(const sentinel_t<_Base>& __y, const _Iterator& __x)
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
+ { return __y - __x._M_current; }
+
+ friend constexpr difference_type
+ operator-(const _Iterator& __x, const sentinel_t<_Base>& __y)
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
+ { return __x._M_current - __y; }
+
+ friend constexpr range_rvalue_reference_t<_Base>
+ iter_move(const _Iterator& __i)
+ noexcept(noexcept(ranges::iter_move(__i._M_current)))
+ { return ranges::iter_move(__i._M_current); }
+
+ friend constexpr void
+ iter_swap(const _Iterator& __x, const _Iterator& __y)
+ noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
+ requires indirectly_swappable<iterator_t<_Base>>
+ { ranges::iter_swap(__x._M_current, __y._M_current); }
+ };
+
+ namespace views
+ {
+ namespace __detail
+ {
+ template<typename _Tp>
+ concept __can_to_input = requires { to_input_view(std::declval<_Tp>());
};
+ }
+
+ struct _ToInput : __adaptor::_RangeAdaptorClosure<_ToInput>
+ {
+ template<viewable_range _Range>
+ requires __detail::__can_to_input<_Range>
+ constexpr auto
+ operator() [[nodiscard]] (_Range&& __r) const
+ {
+ if constexpr (input_range<_Range>
+ && !common_range<_Range>
+ && !forward_range<_Range>)
+ return views::all(std::forward<_Range>(__r));
+ else
+ return to_input_view(std::forward<_Range>(__r));
+ }
+
+ static constexpr bool _S_has_simple_call_op = true;
+ };
+
+ inline constexpr _ToInput to_input;
+ }
+} // namespace ranges
+#endif // __cpp_lib_ranges_to_input
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // library concepts
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/to_input/1.cc
b/libstdc++-v3/testsuite/std/ranges/adaptors/to_input/1.cc
new file mode 100644
index 000000000000..cde368a2f64d
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/to_input/1.cc
@@ -0,0 +1,59 @@
+// { dg-do run { target c++26 } }
+
+#include <ranges>
+
+#if __cpp_lib_ranges_to_input != 202502L
+# error "Feature-test macro __cpp_lib_ranges_to_input has wrong value in
<ranges>"
+#endif
+
+#include <algorithm>
+#include <vector>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+namespace views = std::views;
+
+void
+test01()
+{
+ std::vector<int> r{1,2,3};
+ auto v = r | views::to_input;
+ using type = decltype(v);
+ static_assert( ranges::input_range<type> && !ranges::forward_range<type> );
+
+ VERIFY( ranges::equal(v.base(), r) );
+ VERIFY( v.size() == r.size() );
+ VERIFY( v.end() == r.end() );
+ auto it = v.begin();
+ VERIFY( it != r.end() );
+ *it = 42;
+ ++it;
+ *it = 43;
+ it++;
+ ranges::iter_swap(v.begin(), it);
+ VERIFY( ranges::equal(r, (int[]){3,43,42}) );
+ *it = ranges::iter_move(it);
+ VERIFY( it == r.begin() + 2 );
+ VERIFY( r.end() - it == 1 );
+ VERIFY( it - r.end() == -1 );
+}
+
+void
+test02()
+{
+ int x[] = {1,2,3};
+ __gnu_test::test_input_range<int> rx(x);
+ static_assert( !ranges::common_range<decltype(rx)> );
+ auto v = rx | views::to_input;
+ static_assert( std::same_as<decltype(v), decltype(views::all(rx))> );
+ static_assert( std::same_as<decltype(x | views::to_input),
+ decltype(x | views::to_input | views::to_input)>
);
+}
+
+int
+main()
+{
+ test01();
+ test02();
+}
