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libstdc++: Do not use CTAD for _Utf32_view alias template

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We were relying on P1814R0 (CTAD for alias templates) which isn't
supported by Clang. We can just not use CTAD and provide an explicit
template argument list for _Utf32_view.

Ideally we'd define a deduction guide for _Grapheme_cluster_view that
uses views::all_t to properly convert non-views to views, but all_t is
defined in <ranges> and we don't want to include all of that in
<bits/unicode.h>. So just make it require a view for now, which can be
cheaply copied.

Although it's not needed yet, it would also be more correct to
specialize enable_borrowed_range for the views in <bits/unicode.h>.

libstdc++-v3/ChangeLog:

	* include/bits/unicode.h (_Grapheme_cluster_view): Require view.
	Do not use CTAD for _Utf32_view.
	(__format_width, __truncate): Do not use CTAD.
	(enable_borrowed_range<_Utf_view<T, R>>): Define specialization.
	(enable_borrowed_range<_Grapheme_cluster_view<R>>): Likewise.
This commit is contained in:
Jonathan Wakely 2024-01-16 17:15:26 +00:00
parent 3fd32d3d22
commit 665a3ff153
1 changed files with 18 additions and 5 deletions
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23
libstdc++-v3/include/bits/unicode.h
View file

@ -714,15 +714,15 @@ inline namespace __v15_1_0
};
// Split a range into extended grapheme clusters.
template<ranges::forward_range _View>
template<ranges::forward_range _View> requires ranges::view<_View>
class _Grapheme_cluster_view
: public ranges::view_interface<_Grapheme_cluster_view<_View>>
{
public:
constexpr
_Grapheme_cluster_view(const _View& __v)
: _M_begin(_Utf32_view(__v).begin())
_Grapheme_cluster_view(_View __v)
: _M_begin(_Utf32_view<_View>(std::move(__v)).begin())
{ }
constexpr auto begin() const { return _M_begin; }
@ -946,7 +946,7 @@ inline namespace __v15_1_0
{
if (__s.empty()) [[unlikely]]
return 0;
_Grapheme_cluster_view __gc(__s);
_Grapheme_cluster_view<basic_string_view<_CharT>> __gc(__s);
auto __it = __gc.begin();
const auto __end = __gc.end();
size_t __n = __it.width();
@ -964,7 +964,7 @@ inline namespace __v15_1_0
if (__s.empty()) [[unlikely]]
return 0;
_Grapheme_cluster_view __gc(__s);
_Grapheme_cluster_view<basic_string_view<_CharT>> __gc(__s);
auto __it = __gc.begin();
const auto __end = __gc.end();
size_t __n = __it.width();
@ -1058,6 +1058,19 @@ inline namespace __v15_1_0
} // namespace __unicode
namespace ranges
{
template<typename _To, typename _Range>
inline constexpr bool
enable_borrowed_range<std::__unicode::_Utf_view<_To, _Range>>
= enable_borrowed_range<_Range>;
template<typename _Range>
inline constexpr bool
enable_borrowed_range<std::__unicode::_Grapheme_cluster_view<_Range>>
= enable_borrowed_range<_Range>;
} // namespace ranges
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++20