On Wed, Jun 4, 2025 at 1:19 PM Tomasz Kaminski <tkami...@redhat.com> wrote:
> Ah, sorry I got confused in the review suggestions, and latter when
> checking the code.
> What I meant is:
>
> Because the incoming strided_layout is required to be unique,
> that implies that for each of strides are greater or equal to the extents.
> As a consequence, other.required_span_size() is always greater than equal
> to size of index_space,
> so we can have static assert like:
> static_assert(__mdspan::__representable_size<_OExtents, index_type>,
> "other.required_span_size() must be representable as index_type");
> In here:
> if constexpr (cmp_greater(
> numeric_limits<typename
> _StridedMapping::index_type>::max(),
> numeric_limits<index_type>::max()))
> {
> static_assert(__mdspan::__representable_size<_OExtents,
> index_type>,
> "other.required_span_size() must be representable as
> index_type")
> __glibcxx_assert(!cmp_less(numeric_limits<index_type>::max(),
> __other.required_span_size()));
> }
>
This is assuming that layout is not empty,
but __mdspan::__representable_size already takes care of that,
and triggers only if all extents are static and non-zero.
>
>
>
> On Wed, Jun 4, 2025 at 1:09 PM Luc Grosheintz <luc.groshei...@gmail.com>
> wrote:
>
>>
>>
>> On 6/3/25 15:24, Tomasz Kaminski wrote:
>> > On Fri, May 30, 2025 at 6:44 PM Luc Grosheintz <
>> luc.groshei...@gmail.com>
>> > wrote:
>> >
>> >> Implements the tests for layout_stride and for the features of the
>> other
>> >> two layouts that depend on layout_stride.
>> >>
>> >> libstdc++-v3/ChangeLog:
>> >>
>> >> *
>> testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc: Add
>> >> tests for layout_stride.
>> >> * testsuite/23_containers/mdspan/layouts/ctors.cc: Add test
>> for
>> >> layout_stride and the interaction with other layouts.
>> >> * testsuite/23_containers/mdspan/layouts/mapping.cc: Ditto.
>> >> * testsuite/23_containers/mdspan/layouts/stride.cc: New test.
>> >>
>> >> Signed-off-by: Luc Grosheintz <luc.groshei...@gmail.com>
>> >> ---
>> >>
>> > LTGM. Only one comment regarding the tests that we could add.
>> >
>> >> .../mdspan/layouts/class_mandate_neg.cc | 3 +
>> >> .../23_containers/mdspan/layouts/ctors.cc | 99 ++++
>> >> .../23_containers/mdspan/layouts/empty.cc | 1 +
>> >> .../23_containers/mdspan/layouts/mapping.cc | 75 ++-
>> >> .../23_containers/mdspan/layouts/stride.cc | 526
>> ++++++++++++++++++
>> >> 5 files changed, 703 insertions(+), 1 deletion(-)
>> >> create mode 100644
>> >> libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> >>
>> >> diff --git
>> >>
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> >>
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> >> index 6469fa601e9..6862ed0c0ae 100644
>> >> ---
>> >>
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> >> +++
>> >>
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> >> @@ -31,9 +31,12 @@ template<size_t Count, typename Layout, typename
>> >> OLayout>
>> >>
>> >> A<std::layout_left> a_left; // { dg-error
>> "required
>> >> from" }
>> >> A<std::layout_right> a_right; // { dg-error
>> "required
>> >> from" }
>> >> +A<std::layout_stride> a_stride; // { dg-error
>> "required
>> >> from" }
>> >>
>> >> B<1, std::layout_left, std::layout_left> bll; // { dg-error
>> "required
>> >> here" }
>> >> +B<2, std::layout_left, std::layout_stride> bls; // { dg-error
>> "required
>> >> here" }
>> >>
>> > With the message that we added to static assert to layout_stride
>> > constructor:
>> > >> "other.required_span_size() must be representable as index_type"
>> > I believe you could add here:
>> > B<2, std::layout_stride, std::layout_left>
>> > And similarly for layout_right.
>>
>> I've tried (even before) and always failed miserably. Only good news
>> is that the final
>>
>> // { dg-prune-output "must be representable as index_type" }
>>
>> isn't superfluous. I seem like the only string I can match against
>> is the one associated with that line of code, in this case that's
>>
>> mdspan:773: error: static assertion failed: The size of OtherExtents
>> must be representable as index_type
>> [ ... ]
>> class_mandate_neg.cc:40: note: synthesized method 'constexpr B<4,
>> std::layout_right, std::layout_stride>::B()' first required here
>>
>> I unsure why you're saying that we added the message:
>>
>> "other.required_span_size() must be representable as index_type"
>>
>> to a static_assert, we added it to a __glibcxx_assert. The tests here
>> are designed to trigger different assertions.
>>
>> "A" triggers:
>>
>> template<typename _Extents>
>> class layout_*::mapping
>> {
>> public:
>> // ...
>>
>> static_assert(__mdspan::__representable_size<extents_type,
>> index_type>,
>> "The size of extents_type must be representable as index_type");
>>
>>
>> "B" triggers:
>>
>> template<typename _OExtents>
>> constexpr explicit
>> mapping(const _OExtents& __oexts, __mdspan::__internal_ctor) noexcept
>> : _M_extents(__oexts)
>> {
>> static_assert(__mdspan::__representable_size<_OExtents,
>> index_type>,
>> "The size of OtherExtents must be representable as index_type");
>>
>> We don't have tests that make __glibcxx_assert's fail. We could probably
>> do it with constexpr variables with "dynamic" extents.
>>
>> >
>> >>
>> >> B<3, std::layout_right, std::layout_right> brr; // { dg-error
>> "required
>> >> here" }
>> >> +B<4, std::layout_right, std::layout_stride> brs; // { dg-error
>> "required
>> >> here" }
>> >>
>> >> // { dg-prune-output "must be representable as index_type" }
>> >> diff --git
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> >> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> >> index b0e03161874..695e887ca87 100644
>> >> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> >> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> >> @@ -323,6 +323,104 @@ namespace from_left_or_right
>> >> }
>> >> }
>> >>
>> >> +// ctor: mapping(layout_stride::mapping<OExtents>)
>> >> +namespace from_stride
>> >> +{
>> >> + template<typename Mapping>
>> >> + constexpr auto
>> >> + strides(Mapping m)
>> >> + {
>> >> + constexpr auto rank = Mapping::extents_type::rank();
>> >> + std::array<typename Mapping::index_type, rank> s;
>> >> +
>> >> + if constexpr (rank > 0)
>> >> + for(size_t i = 0; i < rank; ++i)
>> >> + s[i] = m.stride(i);
>> >> + return s;
>> >> + }
>> >> +
>> >> + template<typename Layout, typename Extents, typename OExtents>
>> >> + constexpr void
>> >> + verify_convertible(OExtents oexts)
>> >> + {
>> >> + using Mapping = typename Layout::mapping<Extents>;
>> >> + using OMapping = std::layout_stride::mapping<OExtents>;
>> >> +
>> >> + constexpr auto other = OMapping(oexts,
>> >> strides(Mapping(Extents(oexts))));
>> >> + if constexpr (std::is_same_v<Layout, std::layout_right>)
>> >> + ::verify_nothrow_convertible<Mapping>(other);
>> >> + else
>> >> + ::verify_convertible<Mapping>(other);
>> >> + }
>> >> +
>> >> + template<typename Layout, typename Extents, typename OExtents>
>> >> + constexpr void
>> >> + verify_constructible(OExtents oexts)
>> >> + {
>> >> + using Mapping = typename Layout::mapping<Extents>;
>> >> + using OMapping = std::layout_stride::mapping<OExtents>;
>> >> +
>> >> + constexpr auto other = OMapping(oexts,
>> >> strides(Mapping(Extents(oexts))));
>> >> + if constexpr (std::is_same_v<Layout, std::layout_right>)
>> >> + ::verify_nothrow_constructible<Mapping>(other);
>> >> + else
>> >> + ::verify_constructible<Mapping>(other);
>> >> + }
>> >> +
>> >> + template<typename Layout>
>> >> + constexpr bool
>> >> + test_ctor()
>> >> + {
>> >> + assert_not_constructible<
>> >> + typename Layout::mapping<std::extents<int>>,
>> >> + std::layout_stride::mapping<std::extents<int, 1>>>();
>> >> +
>> >> + assert_not_constructible<
>> >> + typename Layout::mapping<std::extents<int, 1>>,
>> >> + std::layout_stride::mapping<std::extents<int>>>();
>> >> +
>> >> + assert_not_constructible<
>> >> + typename Layout::mapping<std::extents<int, 2>>,
>> >> + std::layout_stride::mapping<std::extents<int, 1>>>();
>> >> +
>> >> + verify_convertible<Layout,
>> std::extents<int>>(std::extents<int>{});
>> >> +
>> >> + verify_convertible<Layout, std::extents<unsigned int>>(
>> >> + std::extents<int>{});
>> >> +
>> >> + // Rank == 0 doesn't check IndexType for convertibility.
>> >> + verify_convertible<Layout, std::extents<int>>(
>> >> + std::extents<unsigned int>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<int, 3>>(
>> >> + std::extents<int, 3>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<unsigned int, 3>>(
>> >> + std::extents<int, 3>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<int, 3>>(
>> >> + std::extents<unsigned int, 3>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<int, 3, 5>>(
>> >> + std::extents<int, 3, 5>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<unsigned int, 3, 5>>(
>> >> + std::extents<int, 3, 5>{});
>> >> +
>> >> + verify_constructible<Layout, std::extents<int, 3, 5>>(
>> >> + std::extents<unsigned int, 3, 5>{});
>> >> + return true;
>> >> + }
>> >> +
>> >> + template<typename Layout>
>> >> + constexpr void
>> >> + test_all()
>> >> + {
>> >> + test_ctor<Layout>();
>> >> + static_assert(test_ctor<Layout>());
>> >> + }
>> >> +}
>> >> +
>> >> template<typename Layout>
>> >> constexpr void
>> >> test_all()
>> >> @@ -330,6 +428,7 @@ template<typename Layout>
>> >> default_ctor::test_all<Layout>();
>> >> from_extents::test_all<Layout>();
>> >> from_same_layout::test_all<Layout>();
>> >> + from_stride::test_all<Layout>();
>> >> }
>> >>
>> >> int
>> >> diff --git
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> >> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> >> index dc2a95ebbe6..d550c0a8e84 100644
>> >> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> >> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> >> @@ -64,5 +64,6 @@ main()
>> >> {
>> >> static_assert(test_all<std::layout_left>());
>> >> static_assert(test_all<std::layout_right>());
>> >> + static_assert(test_all<std::layout_stride>());
>> >> return 0;
>> >> }
>> >> diff --git
>> >> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> >> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> >> index 4dc0db66865..963c804a369 100644
>> >> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> >> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> >> @@ -12,6 +12,7 @@ template<typename Layout, typename Extents>
>> >> {
>> >> using M = typename Layout::mapping<Extents>;
>> >> static_assert(std::__mdspan::__is_extents<typename
>> M::extents_type>);
>> >> + static_assert(std::__mdspan::__mapping_alike<M>);
>> >> static_assert(std::copyable<M>);
>> >> static_assert(std::is_nothrow_move_constructible_v<M>);
>> >> static_assert(std::is_nothrow_move_assignable_v<M>);
>> >> @@ -30,6 +31,8 @@ template<typename Layout, typename Extents>
>> >>
>> >> static_assert(M::is_always_unique() && M::is_unique());
>> >> static_assert(M::is_always_strided() && M::is_strided());
>> >> + if constexpr (!std::is_same_v<Layout, std::layout_stride>)
>> >> + static_assert(M::is_always_exhaustive() && M::is_exhaustive());
>> >> return true;
>> >> }
>> >>
>> >> @@ -105,6 +108,39 @@ template<typename Layout>
>> >> { return exts; }
>> >> };
>> >>
>> >> +template<>
>> >> + struct MappingFactory<std::layout_stride>
>> >> + {
>> >> + template<typename Extents>
>> >> + static constexpr std::layout_stride::mapping<Extents>
>> >> + create(Extents exts)
>> >> + {
>> >> + if constexpr (Extents::rank() == 0)
>> >> + {
>> >> + auto strides = std::array<size_t, 0>{};
>> >> + return std::layout_stride::mapping(exts, strides);
>> >> + }
>> >> + else if constexpr (Extents::rank() == 1)
>> >> + {
>> >> + auto strides = std::array<size_t, 1>{2};
>> >> + return std::layout_stride::mapping(exts, strides);
>> >> + }
>> >> + else if constexpr (Extents::rank() == 2)
>> >> + {
>> >> + size_t m = exts.extent(1);
>> >> + auto strides = std::array<size_t, 2>{3*m, 2};
>> >> + return std::layout_stride::mapping(exts, strides);
>> >> + }
>> >> + else if constexpr (Extents::rank() == 3)
>> >> + {
>> >> + size_t n = exts.extent(0);
>> >> + size_t m = exts.extent(1);
>> >> + auto strides = std::array<size_t, 3>{3*m, 2, 11*m*n};
>> >> + return std::layout_stride::mapping(exts, strides);
>> >> + }
>> >> + }
>> >> + };
>> >> +
>> >> template<typename Layout>
>> >> constexpr void
>> >> test_linear_index_3d()
>> >> @@ -280,6 +316,16 @@ template<typename Layout>
>> >> VERIFY(m.stride(0) == 1);
>> >> }
>> >>
>> >> +template<>
>> >> + constexpr void
>> >> + test_stride_1d<std::layout_stride>()
>> >> + {
>> >> + std::array<int, 1> strides{13};
>> >> + std::layout_stride::mapping m(std::extents<int, 3>{}, strides);
>> >> + VERIFY(m.stride(0) == strides[0]);
>> >> + VERIFY(m.strides() == strides);
>> >> + }
>> >> +
>> >> template<typename Layout>
>> >> constexpr void
>> >> test_stride_2d();
>> >> @@ -302,6 +348,17 @@ template<>
>> >> VERIFY(m.stride(1) == 1);
>> >> }
>> >>
>> >> +template<>
>> >> + constexpr void
>> >> + test_stride_2d<std::layout_stride>()
>> >> + {
>> >> + std::array<int, 2> strides{13, 2};
>> >> + std::layout_stride::mapping m(std::extents<int, 3, 5>{}, strides);
>> >> + VERIFY(m.stride(0) == strides[0]);
>> >> + VERIFY(m.stride(1) == strides[1]);
>> >> + VERIFY(m.strides() == strides);
>> >> + }
>> >> +
>> >> template<typename Layout>
>> >> constexpr void
>> >> test_stride_3d();
>> >> @@ -326,6 +383,19 @@ template<>
>> >> VERIFY(m.stride(2) == 1);
>> >> }
>> >>
>> >> +template<>
>> >> + constexpr void
>> >> + test_stride_3d<std::layout_stride>()
>> >> + {
>> >> + std::dextents<int, 3> exts(3, 5, 7);
>> >> + std::array<int, 3> strides{11, 2, 41};
>> >> + std::layout_stride::mapping<std::dextents<int, 3>> m(exts,
>> strides);
>> >> + VERIFY(m.stride(0) == strides[0]);
>> >> + VERIFY(m.stride(1) == strides[1]);
>> >> + VERIFY(m.stride(2) == strides[2]);
>> >> + VERIFY(m.strides() == strides);
>> >> + }
>> >> +
>> >> template<typename Layout>
>> >> constexpr bool
>> >> test_stride_all()
>> >> @@ -347,7 +417,7 @@ template<typename Layout>
>> >> test_has_stride_0d()
>> >> {
>> >> using Mapping = typename Layout::mapping<std::extents<int>>;
>> >> - constexpr bool expected = false;
>> >> + constexpr bool expected = std::is_same_v<Layout,
>> std::layout_stride>;
>> >> static_assert(has_stride<Mapping> == expected);
>> >> }
>> >>
>> >> @@ -488,8 +558,11 @@ main()
>> >> {
>> >> test_all<std::layout_left>();
>> >> test_all<std::layout_right>();
>> >> + test_all<std::layout_stride>();
>> >>
>> >> test_has_op_eq<std::layout_right, std::layout_left, false>();
>> >> + test_has_op_eq<std::layout_right, std::layout_stride, true>();
>> >> + test_has_op_eq<std::layout_left, std::layout_stride, true>();
>> >> test_has_op_eq_peculiar();
>> >> return 0;
>> >> }
>> >> diff --git
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> >> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> >> new file mode 100644
>> >> index 00000000000..c8af5c61254
>> >> --- /dev/null
>> >> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> >> @@ -0,0 +1,526 @@
>> >> +// { dg-do run { target c++23 } }
>> >> +#include <mdspan>
>> >> +
>> >> +#include <testsuite_hooks.h>
>> >> +
>> >> +constexpr size_t dyn = std::dynamic_extent;
>> >> +
>> >> +template<typename MappingStride>
>> >> + constexpr void
>> >> + test_ctor_default_stride()
>> >> + {
>> >> + using Extents = typename MappingStride::extents_type;
>> >> + MappingStride actual;
>> >> + typename std::layout_right::mapping<Extents> expected;
>> >> +
>> >> + constexpr auto rank = MappingStride::extents_type::rank();
>> >> + if constexpr (rank > 0)
>> >> + for(size_t i = 0; i < rank; ++i)
>> >> + VERIFY(actual.stride(i) == expected.stride(i));
>> >> + }
>> >> +
>> >> +constexpr bool
>> >> +test_ctor_default_stride_all()
>> >> +{
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::extents<int, 3>>>();
>> >> +
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::extents<int, 3, 5, 7>>>();
>> >> +
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::dextents<int, 3>>>();
>> >> +
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::extents<int, 0, 5, 7>>>();
>> >> +
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::extents<int, 3, dyn, dyn>>>();
>> >> +
>> >> + test_ctor_default_stride<
>> >> + std::layout_stride::mapping<std::extents<int, dyn, dyn, 3>>>();
>> >> + return true;
>> >> +}
>> >> +
>> >> +struct IntLikeA
>> >> +{
>> >> + operator int()
>> >> + { return 0; }
>> >> +};
>> >> +
>> >> +struct IntLikeB
>> >> +{
>> >> + operator int() noexcept
>> >> + { return 0; }
>> >> +};
>> >> +
>> >> +struct NotIntLike
>> >> +{ };
>> >> +
>> >> +template<typename E, typename E_arg, typename T, size_t N, bool
>> Expected>
>> >> +constexpr void
>> >> +test_stride_constructible()
>> >> +{
>> >> + static_assert(std::is_nothrow_constructible_v<
>> >> + std::layout_stride::mapping<E>, E_arg, std::span<T, N>> ==
>> >> Expected);
>> >> + static_assert(std::is_nothrow_constructible_v<
>> >> + std::layout_stride::mapping<E>, E_arg, std::array<T, N>> ==
>> >> Expected);
>> >> +
>> static_assert(!std::is_constructible_v<std::layout_stride::mapping<E>,
>> >> + E_arg>);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_stride_constructible_all()
>> >> +{
>> >> + using E0 = std::extents<int>;
>> >> + using E1 = std::extents<int, 2>;
>> >> + using E2 = std::extents<int, dyn>;
>> >> +
>> >> + test_stride_constructible<E0, E0, int, 0, true>();
>> >> + test_stride_constructible<E0, E0, IntLikeA, 0, false>();
>> >> + test_stride_constructible<E0, E0, IntLikeB, 0, true>();
>> >> + test_stride_constructible<E0, E0, NotIntLike, 0, false>();
>> >> + test_stride_constructible<E1, E1, int, 1, true>();
>> >> + test_stride_constructible<E2, E1, int, 1, true>();
>> >> + test_stride_constructible<E1, E1, int, 2, false>();
>> >> + test_stride_constructible<E1, E0, int, 1, false>();
>> >> +}
>> >> +
>> >> +template<typename Extents, typename Shape>
>> >> + constexpr void
>> >> + test_ctor_shape_strides(Extents exts, Shape strides)
>> >> + {
>> >> + using M = std::layout_stride::mapping<Extents>;
>> >> + M m(exts, strides);
>> >> +
>> >> + if constexpr (Extents::rank() > 0)
>> >> + for(size_t i = 0; i < exts.rank(); ++i)
>> >> + {
>> >> + VERIFY(m.stride(i) == strides[i]);
>> >> + VERIFY(m.extents().extent(i) == exts.extent(i));
>> >> + }
>> >> + }
>> >> +
>> >> +constexpr bool
>> >> +test_ctor_shape_stride_all()
>> >> +{
>> >> + test_ctor_shape_strides(std::extents<int>{}, std::array<int, 0>{});
>> >> + test_ctor_shape_strides(std::extents<int, 2>{}, std::array<int,
>> 1>{3});
>> >> + test_ctor_shape_strides(std::extents<int, 2, 4, 6>{},
>> >> + std::array<int, 3>{20, 5, 45});
>> >> + return true;
>> >> +}
>> >> +
>> >> +template<typename Extents, std::array<bool, 2> Strided,
>> >> + std::array<bool, 2> Unique, std::array<bool, 2> Exhautive,
>> >> + typename Extents::index_type Offset = 0>
>> >> + struct MappingLike
>> >> + {
>> >> + using extents_type = Extents;
>> >> + using index_type = typename Extents::index_type;
>> >> +
>> >> + constexpr
>> >> + MappingLike(extents_type extents,
>> >> + std::array<index_type, Extents::rank()> strides)
>> >> + : _extents(extents), _strides(strides)
>> >> + { }
>> >> +
>> >> + static constexpr bool
>> >> + is_always_strided() requires (Strided[0])
>> >> + { return Strided[1]; }
>> >> +
>> >> + static constexpr bool
>> >> + is_always_unique() requires (Unique[0])
>> >> + { return Unique[1]; }
>> >> +
>> >> + static constexpr bool
>> >> + is_always_exhaustive() requires (Exhautive[0])
>> >> + { return Exhautive[1]; }
>> >> +
>> >> + constexpr Extents
>> >> + extents() const { return _extents; }
>> >> +
>> >> + constexpr index_type
>> >> + stride(size_t i) const { return _strides[i]; }
>> >> +
>> >> + template<typename... Indices>
>> >> + constexpr index_type
>> >> + operator()(Indices... indices) const
>> >> + {
>> >> + if (empty())
>> >> + VERIFY(false);
>> >> +
>> >> + std::array<index_type, Extents::rank()> ind_arr{indices...};
>> >> + index_type ret = Offset;
>> >> + for(size_t i = 0; i < Extents::rank(); ++i)
>> >> + ret += ind_arr[i]*_strides[i];
>> >> + return ret;
>> >> + }
>> >> +
>> >> + private:
>> >> + constexpr bool
>> >> + empty() const
>> >> + {
>> >> + for (size_t i = 0; i < extents_type::rank(); ++i)
>> >> + if (_extents.extent(i) == 0)
>> >> + return true;
>> >> + return false;
>> >> + }
>> >> +
>> >> + Extents _extents;
>> >> + std::array<index_type, Extents::rank()> _strides;
>> >> + };
>> >> +
>> >> +
>> >> +template<size_t Rank>
>> >> +struct ExtentLike
>> >> +{
>> >> + using index_type = int;
>> >> +
>> >> + static constexpr size_t
>> >> + rank() { return Rank; }
>> >> +};
>> >> +
>> >> +
>> >> +template<typename E1>
>> >> +constexpr void
>> >> +test_mapping_like_constructible()
>> >> +{
>> >> + using M = std::layout_stride::mapping<E1>;
>> >> + using E2 = std::dextents<typename E1::index_type, E1::rank()>;
>> >> + using E3 = std::dextents<typename E1::index_type, E1::rank() + 1>;
>> >> + using E4 = ExtentLike<E1::rank()>;
>> >> +
>> >> + constexpr auto TT = std::array{true, true};
>> >> + constexpr auto FT = std::array{false, true};
>> >> + constexpr auto TF = std::array{true, false};
>> >> +
>> >> + static_assert(std::is_constructible_v<M, MappingLike<E1, TT, TT,
>> TT>>);
>> >> + static_assert(std::is_constructible_v<M, MappingLike<E2, TT, TT,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E3, TT, TT,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E1, FT, TT,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E1, TF, TT,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, FT,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, TF,
>> TT>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, TT,
>> FT>>);
>> >> + static_assert(std::is_constructible_v<M, MappingLike<E1, TT, TT,
>> TF>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E4, TT, TT,
>> TF>>);
>> >> + static_assert(!std::is_constructible_v<M, MappingLike<E4, TT, TT,
>> TT>>);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_mapping_like_constructible_all()
>> >> +{
>> >> + test_mapping_like_constructible<std::extents<int>>();
>> >> + test_mapping_like_constructible<std::extents<int, 2>>();
>> >> + test_mapping_like_constructible<std::extents<int, 2, 3>>();
>> >> +}
>> >> +
>> >> +template<typename E1, typename E2>
>> >> +constexpr void
>> >> +test_mapping_like_convertible()
>> >> +{
>> >> + using M1 = std::layout_stride::mapping<E1>;
>> >> + using M2 = std::layout_stride::mapping<E2>;
>> >> + constexpr auto TT = std::array{true, true};
>> >> +
>> >> + static_assert(!std::is_convertible_v<MappingLike<E1, TT, TT, TT>,
>> M1>);
>> >> + static_assert(!std::is_convertible_v<MappingLike<E2, TT, TT, TT>,
>> M1>);
>> >> + static_assert(!std::is_convertible_v<MappingLike<E1, TT, TT, TT>,
>> M2>);
>> >> +
>> >> + static_assert(std::is_convertible_v<std::layout_stride::mapping<E2>,
>> >> M1>);
>> >> + static_assert(std::is_convertible_v<std::layout_left::mapping<E2>,
>> M1>);
>> >> + static_assert(std::is_convertible_v<std::layout_right::mapping<E2>,
>> >> M1>);
>> >> +
>> >> +
>> static_assert(!std::is_convertible_v<std::layout_stride::mapping<E1>,
>> >> M2>);
>> >> + static_assert(!std::is_convertible_v<std::layout_left::mapping<E1>,
>> >> M2>);
>> >> + static_assert(!std::is_convertible_v<std::layout_right::mapping<E1>,
>> >> M2>);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_mapping_like_convertible_all()
>> >> +{
>> >> + test_mapping_like_convertible<std::extents<unsigned int>,
>> >> + std::extents<int>>();
>> >> + test_mapping_like_convertible<std::extents<unsigned int, 2>,
>> >> + std::extents<int, 2>>();
>> >> + test_mapping_like_convertible<std::extents<int, dyn, 3>,
>> >> + std::extents<int, 2, 3>>();
>> >> +}
>> >> +
>> >> +template<typename Extents>
>> >> +constexpr void
>> >> +test_ctor_stride_like(Extents exts, std::array<int, Extents::rank()>
>> >> strides)
>> >> +{
>> >> + auto other_right = std::layout_right::mapping(exts);
>> >> + auto other_left = std::layout_left::mapping(exts);
>> >> + auto other_stride = std::layout_stride::mapping(exts, strides);
>> >> +
>> >> + VERIFY(std::layout_stride::mapping<Extents>(other_right) ==
>> >> other_right);
>> >> + VERIFY(std::layout_stride::mapping<Extents>(other_left) ==
>> other_left);
>> >> + VERIFY(std::layout_stride::mapping<Extents>(other_stride) ==
>> >> other_stride);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_ctor_stride_like_all()
>> >> +{
>> >> + using E1 = std::extents<int>;
>> >> + auto s1 = std::array<int, 0>{};
>> >> + test_ctor_stride_like(E1{}, s1);
>> >> +
>> >> + using E2 = std::extents<int, 3>;
>> >> + auto s2 = std::array<int, 1>{2};
>> >> + test_ctor_stride_like(E2{}, s2);
>> >> +
>> >> + using E3 = std::extents<int, 3, 5, 7>;
>> >> + auto s3 = std::array<int, 3>{5, 1, 15};
>> >> + test_ctor_stride_like(E3{}, s3);
>> >> +}
>> >> +
>> >> +constexpr bool
>> >> +test_ctor_strides_all()
>> >> +{
>> >> + test_ctor_default_stride_all();
>> >> + test_ctor_shape_stride_all();
>> >> + test_ctor_stride_like_all();
>> >> + return true;
>> >> +}
>> >> +
>> >> +// Check is_exhaustive.
>> >> +template<typename Extents, typename Strides>
>> >> + constexpr void
>> >> + test_is_exhaustive(Extents extents, Strides strides, bool expected)
>> >> + {
>> >> + std::layout_stride::mapping<Extents> m(extents, strides);
>> >> + VERIFY(m.is_exhaustive() == expected);
>> >> +
>> >> + bool always_exhaustive = extents.rank() == 0 ||
>> >> m.required_span_size() == 0;
>> >> + VERIFY(m.is_always_exhaustive() == always_exhaustive);
>> >> + }
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_zero_1d()
>> >> +{
>> >> + std::extents<int, 0> extents;
>> >> + test_is_exhaustive(extents, std::array{1}, true);
>> >> + test_is_exhaustive(extents, std::array{2}, true);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_zero_3d()
>> >> +{
>> >> + std::extents<int, 3, 0, 7> extents;
>> >> +
>> >> + test_is_exhaustive(extents, std::array{1, 1, 1}, true);
>> >> + test_is_exhaustive(extents, std::array{1, 2*21, 2*3}, true);
>> >> + test_is_exhaustive(extents, std::array{7, 2*21, 1}, true);
>> >> + test_is_exhaustive(extents, std::array{1, 21, 3}, true);
>> >> + test_is_exhaustive(extents, std::array{7, 21, 1}, true);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_0d()
>> >> +{
>> >> + std::extents<int> extents;
>> >> + test_is_exhaustive(extents, std::array<int, 0>{}, true);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_1d()
>> >> +{
>> >> + std::extents<int, 3> extents;
>> >> + test_is_exhaustive(extents, std::array{1}, true);
>> >> + test_is_exhaustive(extents, std::array{3}, false);
>> >> +}
>> >> +
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_3d()
>> >> +{
>> >> + std::extents<int, 3, dyn, 7> extents(5);
>> >> +
>> >> + test_is_exhaustive(extents, std::array{1, 3, 3*5}, true);
>> >> + test_is_exhaustive(extents, std::array{5*7, 1, 5}, true);
>> >> + test_is_exhaustive(extents, std::array{7, 3*7, 1}, true);
>> >> +
>> >> + test_is_exhaustive(extents, std::array{1, 3, 2*3*5}, false);
>> >> + test_is_exhaustive(extents, std::array{2*5*7, 1, 2*5}, false);
>> >> + test_is_exhaustive(extents, std::array{2*7, 2*3*7, 2}, false);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_is_exhaustive_ones()
>> >> +{
>> >> + std::extents<int, 1, 1, 3, 1> extents;
>> >> + test_is_exhaustive(extents, std::array{1, 1, 1, 1}, true);
>> >> + test_is_exhaustive(extents, std::array{1, 1, 1, 3}, true);
>> >> + test_is_exhaustive(extents, std::array{3, 3, 1, 3}, true);
>> >> + test_is_exhaustive(extents, std::array{3, 1, 1, 3}, true);
>> >> +}
>> >> +
>> >> +constexpr bool
>> >> +test_is_exhaustive_all()
>> >> +{
>> >> + test_is_exhaustive_zero_1d();
>> >> + test_is_exhaustive_zero_3d();
>> >> + test_is_exhaustive_ones();
>> >> + test_is_exhaustive_0d();
>> >> + test_is_exhaustive_1d();
>> >> + test_is_exhaustive_3d();
>> >> + return true;
>> >> +}
>> >> +
>> >> +template<typename Extents, int Offset>
>> >> + using OffsetMapping = MappingLike<Extents, {true, true}, {true,
>> true},
>> >> + {true, false}, Offset>;
>> >> +
>> >> +template<typename Extents>
>> >> + constexpr void
>> >> + test_eq(Extents exts,
>> >> + std::array<typename Extents::index_type, Extents::rank()>
>> >> left_strides,
>> >> + std::array<typename Extents::index_type, Extents::rank()>
>> >> right_strides,
>> >> + std::array<typename Extents::index_type, Extents::rank()>
>> >> padded_strides)
>> >> + {
>> >> + using DExtents = std::dextents<int, Extents::rank()>;
>> >> +
>> >> + std::layout_left::mapping<Extents> ml;
>> >> + std::layout_right::mapping<DExtents> mr(exts);
>> >> +
>> >> + std::layout_stride::mapping<Extents> msd;
>> >> + std::layout_stride::mapping<Extents> msl(exts, left_strides);
>> >> + std::layout_stride::mapping<Extents> msr(exts, right_strides);
>> >> + std::layout_stride::mapping<Extents> msp(exts, padded_strides);
>> >> +
>> >> + OffsetMapping<Extents, 0> mor{exts, right_strides};
>> >> + OffsetMapping<Extents, 0> mol{exts, left_strides};
>> >> + OffsetMapping<Extents, 0> mop{exts, padded_strides};
>> >> + OffsetMapping<Extents, 1> moo{exts, right_strides};
>> >> +
>> >> + VERIFY(msd == mr);
>> >> + VERIFY(msd == mor);
>> >> + VERIFY(msd != msp);
>> >> + VERIFY(msd != mop);
>> >> +
>> >> + VERIFY(msl == ml);
>> >> + VERIFY(msl == mol);
>> >> + VERIFY(msd != msp);
>> >> + VERIFY(msl != mop);
>> >> +
>> >> + VERIFY(msp == mop);
>> >> + VERIFY(msp != ml);
>> >> + VERIFY(msp != mr);
>> >> +
>> >> + VERIFY(msd != moo);
>> >> + }
>> >> +
>> >> +constexpr void
>> >> +test_eq_0d()
>> >> +{
>> >> + using Extents = std::extents<int>;
>> >> + Extents exts;
>> >> + std::layout_left::mapping<Extents> ml;
>> >> + std::layout_right::mapping<Extents> mr;
>> >> + std::layout_stride::mapping<Extents> ms;
>> >> + OffsetMapping<Extents, 0> mor{exts, {}};
>> >> + OffsetMapping<Extents, 1> moo{exts, {}};
>> >> +
>> >> + VERIFY(ms == ml);
>> >> + VERIFY(ms == mr);
>> >> + VERIFY(ms == mor);
>> >> + VERIFY(ms != moo);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_eq_1d()
>> >> +{
>> >> + using Extents = std::extents<int, 2>;
>> >> + auto exhaustive_strides = std::array{1};
>> >> + auto padded_strides = std::array{2};
>> >> +
>> >> + test_eq(Extents{}, exhaustive_strides, exhaustive_strides,
>> >> padded_strides);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_eq_2d()
>> >> +{
>> >> + using Extents = std::extents<int, 1, 2>;
>> >> + auto left_strides = std::array{1, 1};
>> >> + auto right_strides = std::array{2, 1};
>> >> + auto padded_strides = std::array{2, 8};
>> >> +
>> >> + test_eq(Extents{}, left_strides, right_strides, padded_strides);
>> >> +}
>> >> +
>> >> +constexpr void
>> >> +test_eq_zero()
>> >> +{
>> >> + using Extents = std::extents<int, 0, 2>;
>> >> + using Mapping = std::layout_stride::mapping<Extents>;
>> >> +
>> >> + Extents exts;
>> >> + std::array<int, 2> sl{1, 5};
>> >> + std::array<int, 2> sr{5, 1};
>> >> +
>> >> + Mapping m1(exts, sl);
>> >> + Mapping m2(exts, sl);
>> >> + Mapping m3(exts, sr);
>> >> + OffsetMapping<Extents, 0> m4(exts, sl);
>> >> +
>> >> + VERIFY(m1 == m2);
>> >> + VERIFY(m1 != m3);
>> >> + VERIFY(m1 == m4);
>> >> +
>> >> +}
>> >> +
>> >> +constexpr bool
>> >> +test_eq_all()
>> >> +{
>> >> + test_eq_0d();
>> >> + test_eq_1d();
>> >> + test_eq_2d();
>> >> + test_eq_zero();
>> >> + return true;
>> >> +}
>> >> +
>> >> +template<typename M1, typename M2>
>> >> + concept has_op_eq = requires (M1 m1, M2 m2)
>> >> + {
>> >> + { m1 == m2 } -> std::same_as<bool>;
>> >> + { m2 == m1 } -> std::same_as<bool>;
>> >> + { m1 != m2 } -> std::same_as<bool>;
>> >> + { m2 != m1 } -> std::same_as<bool>;
>> >> + };
>> >> +
>> >> +constexpr void
>> >> +test_has_op_eq()
>> >> +{
>> >> + using E1 = std::extents<int>;
>> >> + using E2 = std::extents<int, 2>;
>> >> + using E3 = std::extents<int, 1, 2>;
>> >> + constexpr auto FT = std::array{false, true};
>> >> +
>> >> + static_assert(!has_op_eq<
>> >> + std::layout_stride::mapping<E1>, MappingLike<E1, FT, FT, FT>>);
>> >> +
>> >> + static_assert(!has_op_eq<
>> >> + std::layout_stride::mapping<E2>, MappingLike<E2, FT, FT, FT>>);
>> >> +
>> >> + static_assert(!has_op_eq<
>> >> + std::layout_stride::mapping<E3>, MappingLike<E3, FT, FT, FT>>);
>> >> +}
>> >> +
>> >> +int
>> >> +main()
>> >> +{
>> >> + test_ctor_strides_all();
>> >> + static_assert(test_ctor_strides_all());
>> >> + test_mapping_like_convertible_all();
>> >> + test_mapping_like_constructible_all();
>> >> + test_stride_constructible_all();
>> >> + test_is_exhaustive_all();
>> >> + static_assert(test_is_exhaustive_all());
>> >> + test_eq_all();
>> >> + static_assert(test_eq_all());
>> >> + test_has_op_eq();
>> >> + return 0;
>> >> +}
>> >> --
>> >> 2.49.0
>> >>
>> >>
>> >
>>
>>
