* [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view @ 2021-10-19 12:17 Patrick Palka 2021-10-19 12:17 ` [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted Patrick Palka 2021-10-19 12:37 ` [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Jonathan Wakely 0 siblings, 2 replies; 4+ messages in thread From: Patrick Palka @ 2021-10-19 12:17 UTC (permalink / raw) To: gcc-patches; +Cc: libstdc++, Patrick Palka libstdc++-v3/ChangeLog: * include/std/ranges (iota_view::_Iterator): Befriend iota_view. (iota_view::_Sentinel): Likewise. (iota_view::iota_view): Add three overloads each taking an iterator/sentinel pair as per LWG 3523. * testsuite/std/ranges/iota/iota_view.cc (test06): New test. --- libstdc++-v3/include/std/ranges | 21 +++++++++++++++++++ .../testsuite/std/ranges/iota/iota_view.cc | 21 +++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index b8de400dfbb..85f232d8fb9 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -532,6 +532,7 @@ namespace ranges private: _Winc _M_value = _Winc(); + friend iota_view; friend _Sentinel; }; @@ -568,6 +569,8 @@ namespace ranges operator-(const _Sentinel& __x, const _Iterator& __y) requires sized_sentinel_for<_Bound, _Winc> { return __x._M_distance_from(__y); } + + friend iota_view; }; _Winc _M_value = _Winc(); @@ -590,6 +593,24 @@ namespace ranges __glibcxx_assert( bool(__value <= __bound) ); } + constexpr + iota_view(_Iterator __first, _Iterator __last) + requires same_as<_Winc, _Bound> + : iota_view(__first._M_value, __last._M_value) + { } + + constexpr + iota_view(_Iterator __first, unreachable_sentinel_t __last) + requires same_as<_Bound, unreachable_sentinel_t> + : iota_view(__first._M_value, __last) + { } + + constexpr + iota_view(_Iterator __first, _Sentinel __last) + requires (!same_as<_Winc, _Bound>) && (!same_as<_Bound, unreachable_sentinel_t>) + : iota_view(__first._M_value, __last._M_bound) + { } + constexpr _Iterator begin() const { return _Iterator{_M_value}; } diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc index 362ef1f7f78..5bebe4be693 100644 --- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc +++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc @@ -18,6 +18,7 @@ // { dg-options "-std=gnu++2a" } // { dg-do run { target c++2a } } +#include <algorithm> #include <ranges> #include <testsuite_hooks.h> @@ -90,6 +91,25 @@ test05() VERIFY( r.begin() - r.end() == -3 ); } +void +test06() +{ + // Verify LWG 3523 changes. + auto v1 = std::views::iota(0, 5); + auto w1 = decltype(v1)(v1.begin(), v1.end()); + VERIFY( std::ranges::equal(v1, w1) ); + + auto v2 = std::views::iota(0); + auto w2 = decltype(v2)(v2.begin(), v2.end()); + static_assert(std::same_as<decltype(w2.end()), std::unreachable_sentinel_t>); + VERIFY( *w2.begin() == 0 ); + + auto v3 = std::views::iota(0, 5l); + auto w3 = decltype(v3)(v3.begin(), v3.end()); + static_assert(!std::ranges::common_range<decltype(w3)>); + VERIFY( std::ranges::equal(v3, w3) ); +} + int main() { @@ -98,4 +118,5 @@ main() test03(); test04(); test05(); + test06(); } -- 2.33.1.637.gf443b226ca ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted 2021-10-19 12:17 [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Patrick Palka @ 2021-10-19 12:17 ` Patrick Palka 2021-10-21 15:22 ` Jonathan Wakely 2021-10-19 12:37 ` [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Jonathan Wakely 1 sibling, 1 reply; 4+ messages in thread From: Patrick Palka @ 2021-10-19 12:17 UTC (permalink / raw) To: gcc-patches; +Cc: libstdc++, Patrick Palka This implements P1739R4 along with the resolution for LWG 3407 which corrects the paper's wording. Tested on x86_64-pc-linux-gnu, does this look OK for trunk? libstdc++-v3/ChangeLog: * include/bits/ranges_util.h (views::_Drop): Forward declare. (subrange): Befriend views::_Drop. (subrange::_S_store_size): Declare constexpr instead of just const, remove obsolete comment. * include/std/ranges (views::__detail::__is_empty_view): Define. (views::__detail::__is_basic_string_view): Likewise. (views::__detail::__is_subrange): Likewise. (views::__detail::__is_iota_view): Likewise. (views::__detail::__can_take_view): Rename template parm _Tp to _Dp. (views::_Take): Rename template parm _Tp to _Dp, make it non-deducible and fix its type to range_difference_t<_Range>. Implement P1739R4 and LWG 3407 changes. (views::__detail::__can_drop_view): Rename template parm _Tp to _Dp. (views::_Drop): As with views::_Take. (views::_Counted): Implement P1739R4 changes. * include/std/span (__detail::__is_std_span): Rename to ... (__detail::__is_span): ... this and turn it into a variable template. (__detail::__is_std_array): Turn it into a variable template. (span::span): Adjust uses of __is_std_span and __is_std_array accordingly. * testsuite/std/ranges/adaptors/p1739.cc: New test. --- libstdc++-v3/include/bits/ranges_util.h | 7 +- libstdc++-v3/include/std/ranges | 106 +++++++++++++++--- libstdc++-v3/include/std/span | 12 +- .../testsuite/std/ranges/adaptors/p1739.cc | 88 +++++++++++++++ 4 files changed, 192 insertions(+), 21 deletions(-) create mode 100644 libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc diff --git a/libstdc++-v3/include/bits/ranges_util.h b/libstdc++-v3/include/bits/ranges_util.h index 7e7b958d274..1afa66d298c 100644 --- a/libstdc++-v3/include/bits/ranges_util.h +++ b/libstdc++-v3/include/bits/ranges_util.h @@ -211,6 +211,8 @@ namespace ranges } // namespace __detail + namespace views { struct _Drop; } + enum class subrange_kind : bool { unsized, sized }; /// The ranges::subrange class template @@ -221,8 +223,9 @@ namespace ranges class subrange : public view_interface<subrange<_It, _Sent, _Kind>> { private: - // XXX: gcc complains when using constexpr here - static const bool _S_store_size + friend struct views::_Drop; // Needs to inspect _S_store_size. + + static constexpr bool _S_store_size = _Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _It>; _It _M_begin = _It(); diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 85f232d8fb9..64396027c1b 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -42,6 +42,7 @@ #include <initializer_list> #include <iterator> #include <optional> +#include <span> #include <tuple> #include <bits/ranges_util.h> #include <bits/refwrap.h> @@ -2147,19 +2148,66 @@ namespace views::__adaptor { namespace __detail { - template<typename _Range, typename _Tp> + template<typename _Range> + constexpr bool __is_empty_view = false; + + template<typename _Tp> + constexpr bool __is_empty_view<empty_view<_Tp>> = true; + + template<typename _Range> + constexpr bool __is_basic_string_view = false; + + template<typename _CharT, typename _Traits> + constexpr bool __is_basic_string_view<basic_string_view<_CharT, _Traits>> = true; + + template<typename _Range> + constexpr bool __is_subrange = false; + + template<typename _Iter, typename _Sent, subrange_kind _Kind> + constexpr bool __is_subrange<subrange<_Iter, _Sent, _Kind>> = true; + + template<typename _Range> + constexpr bool __is_iota_view = false; + + template<typename _Winc, typename _Bound> + constexpr bool __is_iota_view<iota_view<_Winc, _Bound>> = true; + + template<typename _Range, typename _Dp> concept __can_take_view - = requires { take_view(std::declval<_Range>(), std::declval<_Tp>()); }; + = requires { take_view(std::declval<_Range>(), std::declval<_Dp>()); }; } // namespace __detail struct _Take : __adaptor::_RangeAdaptor<_Take> { - template<viewable_range _Range, typename _Tp> - requires __detail::__can_take_view<_Range, _Tp> + template<viewable_range _Range, typename _Dp = range_difference_t<_Range>> + requires __detail::__can_take_view<_Range, _Dp> constexpr auto - operator() [[nodiscard]] (_Range&& __r, _Tp&& __n) const + operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const { - return take_view(std::forward<_Range>(__r), std::forward<_Tp>(__n)); + using _Tp = remove_cvref_t<_Range>; + if constexpr (__detail::__is_empty_view<_Tp>) + return _Tp(); + else if constexpr (random_access_range<_Tp> + && sized_range<_Tp> + && (std::__detail::__is_span<_Tp> + || __detail::__is_basic_string_view<_Tp> + || __detail::__is_subrange<_Tp> + || __detail::__is_iota_view<_Tp>)) + { + __n = std::min<_Dp>(ranges::distance(__r), __n); + auto __begin = ranges::begin(__r); + auto __end = __begin + __n; + if constexpr (std::__detail::__is_span<_Tp>) + return span<typename _Tp::element_type>(__begin, __end); + else if constexpr (__detail::__is_basic_string_view<_Tp>) + return _Tp(__begin, __end); + else if constexpr (__detail::__is_subrange<_Tp>) + return subrange<iterator_t<_Tp>>(__begin, __end); + else + return iota_view(*__begin, *__end); + } + else + return take_view(std::forward<_Range>(__r), __n); } using _RangeAdaptor<_Take>::operator(); @@ -2394,19 +2442,49 @@ namespace views::__adaptor { namespace __detail { - template<typename _Range, typename _Tp> + template<typename _Range, typename _Dp> concept __can_drop_view - = requires { drop_view(std::declval<_Range>(), std::declval<_Tp>()); }; + = requires { drop_view(std::declval<_Range>(), std::declval<_Dp>()); }; } // namespace __detail struct _Drop : __adaptor::_RangeAdaptor<_Drop> { - template<viewable_range _Range, typename _Tp> - requires __detail::__can_drop_view<_Range, _Tp> + template<viewable_range _Range, typename _Dp = range_difference_t<_Range>> + requires __detail::__can_drop_view<_Range, _Dp> constexpr auto - operator() [[nodiscard]] (_Range&& __r, _Tp&& __n) const + operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const { - return drop_view(std::forward<_Range>(__r), std::forward<_Tp>(__n)); + using _Tp = remove_cvref_t<_Range>; + if constexpr (__detail::__is_empty_view<_Tp>) + return _Tp(); + else if constexpr (random_access_range<_Tp> + && sized_range<_Tp> + && (std::__detail::__is_span<_Tp> + || __detail::__is_basic_string_view<_Tp> + || __detail::__is_iota_view<_Tp> + || __detail::__is_subrange<_Tp>)) + { + __n = std::min<_Dp>(ranges::distance(__r), __n); + auto __begin = ranges::begin(__r) + __n; + auto __end = ranges::end(__r); + if constexpr (std::__detail::__is_span<_Tp>) + return span<typename _Tp::element_type>(__begin, __end); + else if constexpr (__detail::__is_subrange<_Tp>) + { + if constexpr (_Tp::_S_store_size) + { + using ranges::__detail::__to_unsigned_like; + auto __m = ranges::distance(__r) - __n; + return _Tp(__begin, __end, __to_unsigned_like(__m)); + } + else + return _Tp(__begin, __end); + } + else + return _Tp(__begin, __end); + } + else + return drop_view(std::forward<_Range>(__r), __n); } using _RangeAdaptor<_Drop>::operator(); @@ -3536,7 +3614,9 @@ namespace views::__adaptor constexpr auto operator() [[nodiscard]] (_Iter __i, iter_difference_t<_Iter> __n) const { - if constexpr (random_access_iterator<_Iter>) + if constexpr (contiguous_iterator<_Iter>) + return span(std::__to_address(__i), __n); + else if constexpr (random_access_iterator<_Iter>) return subrange(__i, __i + __n); else return subrange(counted_iterator(std::move(__i), __n), diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span index af0d24b29f2..ba75a497310 100644 --- a/libstdc++-v3/include/std/span +++ b/libstdc++-v3/include/std/span @@ -58,16 +58,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace __detail { template<typename _Tp> - struct __is_std_span : false_type { }; + constexpr bool __is_span = false; template<typename _Tp, size_t _Num> - struct __is_std_span<span<_Tp, _Num>> : true_type { }; + constexpr bool __is_span<span<_Tp, _Num>> = true; template<typename _Tp> - struct __is_std_array : false_type { }; + constexpr bool __is_std_array = false; template<typename _Tp, size_t _Num> - struct __is_std_array<std::array<_Tp, _Num>> : true_type { }; + constexpr bool __is_std_array<std::array<_Tp, _Num>> = true; template<size_t _Extent> class __extent_storage @@ -203,8 +203,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Range> requires ranges::contiguous_range<_Range> && ranges::sized_range<_Range> && (ranges::borrowed_range<_Range> || is_const_v<element_type>) - && (!__detail::__is_std_span<remove_cvref_t<_Range>>::value) - && (!__detail::__is_std_array<remove_cvref_t<_Range>>::value) + && (!__detail::__is_span<remove_cvref_t<_Range>>) + && (!__detail::__is_std_array<remove_cvref_t<_Range>>) && (!is_array_v<remove_cvref_t<_Range>>) && __is_compatible_ref<ranges::range_reference_t<_Range>>::value constexpr explicit(extent != dynamic_extent) diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc new file mode 100644 index 00000000000..243b8a03583 --- /dev/null +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc @@ -0,0 +1,88 @@ +// { dg-options "-std=gnu++20" } +// { dg-do run { target c++20 } } + +#include <algorithm> +#include <ranges> +#include <testsuite_hooks.h> + +// Verify P1739R4 (and LWG 3407) changes views::take/drop/counted. + +namespace ranges = std::ranges; +namespace views = ranges::views; + +void +test01() +{ + ranges::empty_view<int> v; + using ty = decltype(v); + using ty = decltype(views::take(v, 42)); + using ty = decltype(views::drop(v, 42)); +} + +void +test02() +{ + int x[] = {1,2,3,4,5}; + std::span r(x, x+5); + using ty = decltype(r); + + std::same_as<ty> auto v1 = views::take(r, 2); + VERIFY( ranges::equal(v1, (int[]){1,2}) ); + + std::same_as<ty> auto v2 = views::drop(r, 3); + VERIFY( ranges::equal(v2, (int[]){4,5}) ); + + std::same_as<ty> auto v3 = views::counted(r.begin(), 4); + VERIFY( ranges::equal(v3, (int[]){1,2,3,4}) ); +} + +void +test03() +{ + using namespace std::literals; + std::string_view r = "hello world"sv; + using ty = decltype(r); + + std::same_as<ty> auto v1 = views::take(r, 5); + VERIFY( ranges::equal(v1, "hello"sv) ); + + std::same_as<ty> auto v2 = views::drop(r, 6); + VERIFY( ranges::equal(v2, "world"sv) ); +} + +void +test04() +{ + int x[] = {1,2,3,4,5}; + ranges::subrange r(x, x+5); + using ty = decltype(r); + + std::same_as<ty> auto v1 = views::take(r, 2); + VERIFY( ranges::equal(v1, (int[]){1,2}) ); + + std::same_as<ty> auto v2 = views::drop(r, 1); + VERIFY( ranges::equal(v2, (int[]){2,3,4,5}) ); +} + +void +test05() +{ + auto r1 = views::iota(1, 6); + using ty1 = decltype(r1); + + std::same_as<ty1> auto v1 = views::take(r1, 2); + VERIFY( ranges::equal(v1, (int[]){1,2}) ); + + std::same_as<ty1> auto v2 = views::drop(r1, 3); + VERIFY( ranges::equal(v2, (int[]){4,5}) ); +} + +int +main() +{ + test01(); + test02(); + test03(); + test04(); + test05(); +} -- 2.33.1.637.gf443b226ca ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted 2021-10-19 12:17 ` [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted Patrick Palka @ 2021-10-21 15:22 ` Jonathan Wakely 0 siblings, 0 replies; 4+ messages in thread From: Jonathan Wakely @ 2021-10-21 15:22 UTC (permalink / raw) To: Patrick Palka; +Cc: gcc Patches, libstdc++ On Tue, 19 Oct 2021 at 13:20, Patrick Palka via Libstdc++ < libstdc++@gcc.gnu.org> wrote: > This implements P1739R4 along with the resolution for LWG 3407 which > corrects the paper's wording. > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk? > Yes, thanks. > libstdc++-v3/ChangeLog: > > * include/bits/ranges_util.h (views::_Drop): Forward declare. > (subrange): Befriend views::_Drop. > (subrange::_S_store_size): Declare constexpr instead of just > const, remove obsolete comment. > * include/std/ranges (views::__detail::__is_empty_view): Define. > (views::__detail::__is_basic_string_view): Likewise. > (views::__detail::__is_subrange): Likewise. > (views::__detail::__is_iota_view): Likewise. > (views::__detail::__can_take_view): Rename template parm _Tp to > _Dp. > (views::_Take): Rename template parm _Tp to _Dp, make it > non-deducible > and fix its type to range_difference_t<_Range>. Implement P1739R4 > and > LWG 3407 changes. > (views::__detail::__can_drop_view): Rename template parm _Tp to > _Dp. > (views::_Drop): As with views::_Take. > (views::_Counted): Implement P1739R4 changes. > * include/std/span (__detail::__is_std_span): Rename to ... > (__detail::__is_span): ... this and turn it into a variable > template. > (__detail::__is_std_array): Turn it into a variable template. > (span::span): Adjust uses of __is_std_span and __is_std_array > accordingly. > * testsuite/std/ranges/adaptors/p1739.cc: New test. > --- > libstdc++-v3/include/bits/ranges_util.h | 7 +- > libstdc++-v3/include/std/ranges | 106 +++++++++++++++--- > libstdc++-v3/include/std/span | 12 +- > .../testsuite/std/ranges/adaptors/p1739.cc | 88 +++++++++++++++ > 4 files changed, 192 insertions(+), 21 deletions(-) > create mode 100644 libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc > > diff --git a/libstdc++-v3/include/bits/ranges_util.h > b/libstdc++-v3/include/bits/ranges_util.h > index 7e7b958d274..1afa66d298c 100644 > --- a/libstdc++-v3/include/bits/ranges_util.h > +++ b/libstdc++-v3/include/bits/ranges_util.h > @@ -211,6 +211,8 @@ namespace ranges > > } // namespace __detail > > + namespace views { struct _Drop; } > + > enum class subrange_kind : bool { unsized, sized }; > > /// The ranges::subrange class template > @@ -221,8 +223,9 @@ namespace ranges > class subrange : public view_interface<subrange<_It, _Sent, _Kind>> > { > private: > - // XXX: gcc complains when using constexpr here > - static const bool _S_store_size > + friend struct views::_Drop; // Needs to inspect _S_store_size. > + > + static constexpr bool _S_store_size > = _Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _It>; > > _It _M_begin = _It(); > diff --git a/libstdc++-v3/include/std/ranges > b/libstdc++-v3/include/std/ranges > index 85f232d8fb9..64396027c1b 100644 > --- a/libstdc++-v3/include/std/ranges > +++ b/libstdc++-v3/include/std/ranges > @@ -42,6 +42,7 @@ > #include <initializer_list> > #include <iterator> > #include <optional> > +#include <span> > #include <tuple> > #include <bits/ranges_util.h> > #include <bits/refwrap.h> > @@ -2147,19 +2148,66 @@ namespace views::__adaptor > { > namespace __detail > { > - template<typename _Range, typename _Tp> > + template<typename _Range> > + constexpr bool __is_empty_view = false; > + > + template<typename _Tp> > + constexpr bool __is_empty_view<empty_view<_Tp>> = true; > + > + template<typename _Range> > + constexpr bool __is_basic_string_view = false; > + > + template<typename _CharT, typename _Traits> > + constexpr bool __is_basic_string_view<basic_string_view<_CharT, > _Traits>> = true; > + > + template<typename _Range> > + constexpr bool __is_subrange = false; > + > + template<typename _Iter, typename _Sent, subrange_kind _Kind> > + constexpr bool __is_subrange<subrange<_Iter, _Sent, _Kind>> = true; > + > + template<typename _Range> > + constexpr bool __is_iota_view = false; > + > + template<typename _Winc, typename _Bound> > + constexpr bool __is_iota_view<iota_view<_Winc, _Bound>> = true; > + > + template<typename _Range, typename _Dp> > concept __can_take_view > - = requires { take_view(std::declval<_Range>(), > std::declval<_Tp>()); }; > + = requires { take_view(std::declval<_Range>(), > std::declval<_Dp>()); }; > } // namespace __detail > > struct _Take : __adaptor::_RangeAdaptor<_Take> > { > - template<viewable_range _Range, typename _Tp> > - requires __detail::__can_take_view<_Range, _Tp> > + template<viewable_range _Range, typename _Dp = > range_difference_t<_Range>> > + requires __detail::__can_take_view<_Range, _Dp> > constexpr auto > - operator() [[nodiscard]] (_Range&& __r, _Tp&& __n) const > + operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) > const > { > - return take_view(std::forward<_Range>(__r), > std::forward<_Tp>(__n)); > + using _Tp = remove_cvref_t<_Range>; > + if constexpr (__detail::__is_empty_view<_Tp>) > + return _Tp(); > + else if constexpr (random_access_range<_Tp> > + && sized_range<_Tp> > + && (std::__detail::__is_span<_Tp> > + || __detail::__is_basic_string_view<_Tp> > + || __detail::__is_subrange<_Tp> > + || __detail::__is_iota_view<_Tp>)) > + { > + __n = std::min<_Dp>(ranges::distance(__r), __n); > + auto __begin = ranges::begin(__r); > + auto __end = __begin + __n; > + if constexpr (std::__detail::__is_span<_Tp>) > + return span<typename _Tp::element_type>(__begin, __end); > + else if constexpr (__detail::__is_basic_string_view<_Tp>) > + return _Tp(__begin, __end); > + else if constexpr (__detail::__is_subrange<_Tp>) > + return subrange<iterator_t<_Tp>>(__begin, __end); > + else > + return iota_view(*__begin, *__end); > + } > + else > + return take_view(std::forward<_Range>(__r), __n); > } > > using _RangeAdaptor<_Take>::operator(); > @@ -2394,19 +2442,49 @@ namespace views::__adaptor > { > namespace __detail > { > - template<typename _Range, typename _Tp> > + template<typename _Range, typename _Dp> > concept __can_drop_view > - = requires { drop_view(std::declval<_Range>(), > std::declval<_Tp>()); }; > + = requires { drop_view(std::declval<_Range>(), > std::declval<_Dp>()); }; > } // namespace __detail > > struct _Drop : __adaptor::_RangeAdaptor<_Drop> > { > - template<viewable_range _Range, typename _Tp> > - requires __detail::__can_drop_view<_Range, _Tp> > + template<viewable_range _Range, typename _Dp = > range_difference_t<_Range>> > + requires __detail::__can_drop_view<_Range, _Dp> > constexpr auto > - operator() [[nodiscard]] (_Range&& __r, _Tp&& __n) const > + operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) > const > { > - return drop_view(std::forward<_Range>(__r), > std::forward<_Tp>(__n)); > + using _Tp = remove_cvref_t<_Range>; > + if constexpr (__detail::__is_empty_view<_Tp>) > + return _Tp(); > + else if constexpr (random_access_range<_Tp> > + && sized_range<_Tp> > + && (std::__detail::__is_span<_Tp> > + || __detail::__is_basic_string_view<_Tp> > + || __detail::__is_iota_view<_Tp> > + || __detail::__is_subrange<_Tp>)) > + { > + __n = std::min<_Dp>(ranges::distance(__r), __n); > + auto __begin = ranges::begin(__r) + __n; > + auto __end = ranges::end(__r); > + if constexpr (std::__detail::__is_span<_Tp>) > + return span<typename _Tp::element_type>(__begin, __end); > + else if constexpr (__detail::__is_subrange<_Tp>) > + { > + if constexpr (_Tp::_S_store_size) > + { > + using ranges::__detail::__to_unsigned_like; > + auto __m = ranges::distance(__r) - __n; > + return _Tp(__begin, __end, __to_unsigned_like(__m)); > + } > + else > + return _Tp(__begin, __end); > + } > + else > + return _Tp(__begin, __end); > + } > + else > + return drop_view(std::forward<_Range>(__r), __n); > } > > using _RangeAdaptor<_Drop>::operator(); > @@ -3536,7 +3614,9 @@ namespace views::__adaptor > constexpr auto > operator() [[nodiscard]] (_Iter __i, iter_difference_t<_Iter> __n) > const > { > - if constexpr (random_access_iterator<_Iter>) > + if constexpr (contiguous_iterator<_Iter>) > + return span(std::__to_address(__i), __n); > + else if constexpr (random_access_iterator<_Iter>) > return subrange(__i, __i + __n); > else > return subrange(counted_iterator(std::move(__i), __n), > diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span > index af0d24b29f2..ba75a497310 100644 > --- a/libstdc++-v3/include/std/span > +++ b/libstdc++-v3/include/std/span > @@ -58,16 +58,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > namespace __detail > { > template<typename _Tp> > - struct __is_std_span : false_type { }; > + constexpr bool __is_span = false; > > template<typename _Tp, size_t _Num> > - struct __is_std_span<span<_Tp, _Num>> : true_type { }; > + constexpr bool __is_span<span<_Tp, _Num>> = true; > > template<typename _Tp> > - struct __is_std_array : false_type { }; > + constexpr bool __is_std_array = false; > > template<typename _Tp, size_t _Num> > - struct __is_std_array<std::array<_Tp, _Num>> : true_type { }; > + constexpr bool __is_std_array<std::array<_Tp, _Num>> = true; > > template<size_t _Extent> > class __extent_storage > @@ -203,8 +203,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > template<typename _Range> > requires ranges::contiguous_range<_Range> && > ranges::sized_range<_Range> > && (ranges::borrowed_range<_Range> || is_const_v<element_type>) > - && (!__detail::__is_std_span<remove_cvref_t<_Range>>::value) > - && (!__detail::__is_std_array<remove_cvref_t<_Range>>::value) > + && (!__detail::__is_span<remove_cvref_t<_Range>>) > + && (!__detail::__is_std_array<remove_cvref_t<_Range>>) > && (!is_array_v<remove_cvref_t<_Range>>) > && __is_compatible_ref<ranges::range_reference_t<_Range>>::value > constexpr explicit(extent != dynamic_extent) > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc > b/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc > new file mode 100644 > index 00000000000..243b8a03583 > --- /dev/null > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/p1739.cc > @@ -0,0 +1,88 @@ > +// { dg-options "-std=gnu++20" } > +// { dg-do run { target c++20 } } > + > +#include <algorithm> > +#include <ranges> > +#include <testsuite_hooks.h> > + > +// Verify P1739R4 (and LWG 3407) changes views::take/drop/counted. > + > +namespace ranges = std::ranges; > +namespace views = ranges::views; > + > +void > +test01() > +{ > + ranges::empty_view<int> v; > + using ty = decltype(v); > + using ty = decltype(views::take(v, 42)); > + using ty = decltype(views::drop(v, 42)); > +} > + > +void > +test02() > +{ > + int x[] = {1,2,3,4,5}; > + std::span r(x, x+5); > + using ty = decltype(r); > + > + std::same_as<ty> auto v1 = views::take(r, 2); > + VERIFY( ranges::equal(v1, (int[]){1,2}) ); > + > + std::same_as<ty> auto v2 = views::drop(r, 3); > + VERIFY( ranges::equal(v2, (int[]){4,5}) ); > + > + std::same_as<ty> auto v3 = views::counted(r.begin(), 4); > + VERIFY( ranges::equal(v3, (int[]){1,2,3,4}) ); > +} > + > +void > +test03() > +{ > + using namespace std::literals; > + std::string_view r = "hello world"sv; > + using ty = decltype(r); > + > + std::same_as<ty> auto v1 = views::take(r, 5); > + VERIFY( ranges::equal(v1, "hello"sv) ); > + > + std::same_as<ty> auto v2 = views::drop(r, 6); > + VERIFY( ranges::equal(v2, "world"sv) ); > +} > + > +void > +test04() > +{ > + int x[] = {1,2,3,4,5}; > + ranges::subrange r(x, x+5); > + using ty = decltype(r); > + > + std::same_as<ty> auto v1 = views::take(r, 2); > + VERIFY( ranges::equal(v1, (int[]){1,2}) ); > + > + std::same_as<ty> auto v2 = views::drop(r, 1); > + VERIFY( ranges::equal(v2, (int[]){2,3,4,5}) ); > +} > + > +void > +test05() > +{ > + auto r1 = views::iota(1, 6); > + using ty1 = decltype(r1); > + > + std::same_as<ty1> auto v1 = views::take(r1, 2); > + VERIFY( ranges::equal(v1, (int[]){1,2}) ); > + > + std::same_as<ty1> auto v2 = views::drop(r1, 3); > + VERIFY( ranges::equal(v2, (int[]){4,5}) ); > +} > + > +int > +main() > +{ > + test01(); > + test02(); > + test03(); > + test04(); > + test05(); > +} > -- > 2.33.1.637.gf443b226ca > > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view 2021-10-19 12:17 [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Patrick Palka 2021-10-19 12:17 ` [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted Patrick Palka @ 2021-10-19 12:37 ` Jonathan Wakely 1 sibling, 0 replies; 4+ messages in thread From: Jonathan Wakely @ 2021-10-19 12:37 UTC (permalink / raw) To: Patrick Palka; +Cc: gcc Patches, libstdc++ On Tue, 19 Oct 2021 at 13:18, Patrick Palka via Libstdc++ <libstdc++@gcc.gnu.org> wrote: > > libstdc++-v3/ChangeLog: > > * include/std/ranges (iota_view::_Iterator): Befriend iota_view. > (iota_view::_Sentinel): Likewise. > (iota_view::iota_view): Add three overloads each taking an > iterator/sentinel pair as per LWG 3523. > * testsuite/std/ranges/iota/iota_view.cc (test06): New test. OK for trunk and gcc-11 (after some soak time), thanks. > --- > libstdc++-v3/include/std/ranges | 21 +++++++++++++++++++ > .../testsuite/std/ranges/iota/iota_view.cc | 21 +++++++++++++++++++ > 2 files changed, 42 insertions(+) > > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges > index b8de400dfbb..85f232d8fb9 100644 > --- a/libstdc++-v3/include/std/ranges > +++ b/libstdc++-v3/include/std/ranges > @@ -532,6 +532,7 @@ namespace ranges > private: > _Winc _M_value = _Winc(); > > + friend iota_view; > friend _Sentinel; > }; > > @@ -568,6 +569,8 @@ namespace ranges > operator-(const _Sentinel& __x, const _Iterator& __y) > requires sized_sentinel_for<_Bound, _Winc> > { return __x._M_distance_from(__y); } > + > + friend iota_view; > }; > > _Winc _M_value = _Winc(); > @@ -590,6 +593,24 @@ namespace ranges > __glibcxx_assert( bool(__value <= __bound) ); > } > > + constexpr > + iota_view(_Iterator __first, _Iterator __last) > + requires same_as<_Winc, _Bound> > + : iota_view(__first._M_value, __last._M_value) > + { } > + > + constexpr > + iota_view(_Iterator __first, unreachable_sentinel_t __last) > + requires same_as<_Bound, unreachable_sentinel_t> > + : iota_view(__first._M_value, __last) > + { } > + > + constexpr > + iota_view(_Iterator __first, _Sentinel __last) > + requires (!same_as<_Winc, _Bound>) && (!same_as<_Bound, unreachable_sentinel_t>) > + : iota_view(__first._M_value, __last._M_bound) > + { } > + > constexpr _Iterator > begin() const { return _Iterator{_M_value}; } > > diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc > index 362ef1f7f78..5bebe4be693 100644 > --- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc > +++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc > @@ -18,6 +18,7 @@ > // { dg-options "-std=gnu++2a" } > // { dg-do run { target c++2a } } > > +#include <algorithm> > #include <ranges> > #include <testsuite_hooks.h> > > @@ -90,6 +91,25 @@ test05() > VERIFY( r.begin() - r.end() == -3 ); > } > > +void > +test06() > +{ > + // Verify LWG 3523 changes. > + auto v1 = std::views::iota(0, 5); > + auto w1 = decltype(v1)(v1.begin(), v1.end()); > + VERIFY( std::ranges::equal(v1, w1) ); > + > + auto v2 = std::views::iota(0); > + auto w2 = decltype(v2)(v2.begin(), v2.end()); > + static_assert(std::same_as<decltype(w2.end()), std::unreachable_sentinel_t>); > + VERIFY( *w2.begin() == 0 ); > + > + auto v3 = std::views::iota(0, 5l); > + auto w3 = decltype(v3)(v3.begin(), v3.end()); > + static_assert(!std::ranges::common_range<decltype(w3)>); > + VERIFY( std::ranges::equal(v3, w3) ); > +} > + > int > main() > { > @@ -98,4 +118,5 @@ main() > test03(); > test04(); > test05(); > + test06(); > } > -- > 2.33.1.637.gf443b226ca > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-10-21 15:23 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-10-19 12:17 [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Patrick Palka 2021-10-19 12:17 ` [PATCH 2/2] libstdc++: Implement P1739R4 changes to views::take/drop/counted Patrick Palka 2021-10-21 15:22 ` Jonathan Wakely 2021-10-19 12:37 ` [PATCH 1/2] libstdc++: Implement LWG 3523 changes to ranges::iota_view Jonathan Wakely
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