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| author | Jonathan Wakely <jwakely@redhat.com> | 2019-12-09 17:35:24 +0000 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2019-12-09 17:35:24 +0000 |
| commit | b5b2e3879db9a251a2e7ff2553e188682d202c7e (patch) | |
| tree | 50bc117800c5e6bc739168e9953df1fcb21505db /libstdc++-v3/include/std/span | |
| parent | 43c2de7a5720e0d6fbc5df8fc6fb03f2dbf164ff (diff) | |
| download | gcc-b5b2e3879db9a251a2e7ff2553e188682d202c7e.zip gcc-b5b2e3879db9a251a2e7ff2553e188682d202c7e.tar.gz gcc-b5b2e3879db9a251a2e7ff2553e188682d202c7e.tar.bz2 | |
libstdc++: Implement ranges::safe_range for C++20 (P1870R1)
This change replaces the __forwarding_range implementation detail with
the ranges::safe_range concept and adds the ranges::enable_safe_range
variable template for opt-in in to the concept.
It also adjusts the begin/end/rbegin/rend customization point objects to
match the new rules for accessing rvalue ranges only when safe to do so.
* include/bits/range_access.h (ranges::enable_safe_range): Define.
(ranges::begin, ranges::end, ranges::rbegin, ranges::rend): Constrain
to only accept types satisfying safe_range and treat argument as an
lvalue when calling a member of performing ADL.
(ranges::__detail::__range_impl, ranges::__detail::__forwarding_range):
Remove.
(ranges::range): Adjust definition.
(ranges::safe_range): Define.
(ranges::iterator_t, ranges::range_difference_t): Reorder definitions
to match the synopsis in the working draft.
(ranges::disable_sized_range): Remove duplicate definition.
* include/experimental/string_view (ranges::enable_safe_range): Add
partial specialization for std::experimental::basic_string_view.
* include/std/ranges (ranges::viewable_range, ranges::subrange)
(ranges::empty_view, ranges::iota_view): Use safe_range. Specialize
enable_safe_range.
(ranges::safe_iterator_t, ranges::safe_subrange_t): Define.
* include/std/span (ranges::enable_safe_range): Add partial
specialization for std::span.
* include/std/string_view (ranges::enable_safe_range): Likewise for
std::basic_string_view.
* testsuite/std/ranges/access/begin.cc: Adjust expected results.
* testsuite/std/ranges/access/cbegin.cc: Likewise.
* testsuite/std/ranges/access/cdata.cc: Likewise.
* testsuite/std/ranges/access/cend.cc: Likewise.
* testsuite/std/ranges/access/crbegin.cc: Likewise.
* testsuite/std/ranges/access/crend.cc: Likewise.
* testsuite/std/ranges/access/data.cc: Likewise.
* testsuite/std/ranges/access/end.cc: Likewise.
* testsuite/std/ranges/access/rbegin.cc: Likewise.
* testsuite/std/ranges/access/rend.cc: Likewise.
* testsuite/std/ranges/empty_view.cc: Test ranges::begin and
ranges::end instead of unqualified calls to begin and end.
* testsuite/std/ranges/safe_range.cc: New test.
* testsuite/std/ranges/safe_range_types.cc: New test.
* testsuite/util/testsuite_iterators.h: Add comment about safe_range.
From-SVN: r279135
Diffstat (limited to 'libstdc++-v3/include/std/span')
| -rw-r--r-- | libstdc++-v3/include/std/span | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span index c71f8bc..f215dec 100644 --- a/libstdc++-v3/include/std/span +++ b/libstdc++-v3/include/std/span @@ -399,16 +399,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return {this->data() + __offset, __count}; } - // observers: range helpers - - friend constexpr iterator - begin(span __sp) noexcept - { return __sp.begin(); } - - friend constexpr iterator - end(span __sp) noexcept - { return __sp.end(); } - private: [[no_unique_address]] __detail::__extent_storage<extent> _M_extent; pointer _M_ptr; @@ -478,6 +468,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION using type = _Type; }; + namespace ranges + { + template<typename> extern inline const bool enable_safe_range; + // Opt-in to safe_range concept + template<typename _ElementType, size_t _Extent> + inline constexpr bool + enable_safe_range<span<_ElementType, _Extent>> = true; + } _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif // concepts |