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Merged
Stephan T. Lavavej (StephanTLavavej) merged 12 commits into from
Aug 15, 2023
Merged

<mdspan>: Product code review #3971

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99fabc9
Unconditionally strengthen `mdspan::is_always_MEOW()`.
StephanTLavavej Aug 15, 2023
2f40cf7
Drop strengthened comment; `_Access_impl()` is `_Ugly`
StephanTLavavej Aug 15, 2023
5529f16
Follow N4950 \[mdspan.mdspan.cons\]/8.1 by saying `const _OtherIndexT…
StephanTLavavej Aug 15, 2023
364622e
In `default_accessor`, define `access()` before `offset()` to follow …
StephanTLavavej Aug 15, 2023
49d335e
`layout_stride::template mapping` is unnecessary; `layout_stride` is …
StephanTLavavej Aug 15, 2023
4ce75ee
Add `explicit` to the deduction guide `extents(_Integrals...)`, depic…
StephanTLavavej Aug 15, 2023
b328d13
Style: Reorder the template parameters for `_Contains_multidimensiona…
StephanTLavavej Aug 15, 2023
7214197
Step 1: Move `_Multidimensional_access()` up.
StephanTLavavej Aug 15, 2023
41c438f
Step 2: Add conditional `noexcept` to `_Multidimensional_access()`, n…
StephanTLavavej Aug 15, 2023
ef8c8c2
Step 3: Add `as_const()` to the `array` overload, so it exactly match…
StephanTLavavej Aug 15, 2023
c193bce
Step 4: Replace lambdas with `_Multidimensional_subscript()`.
StephanTLavavej Aug 15, 2023
1c92a8e
Step 5: Add conditional `noexcept` to `_Multidimensional_subscript` (…
StephanTLavavej Aug 15, 2023
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93 changes: 49 additions & 44 deletions stl/inc/mdspan
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Original file line number Diff line number Diff line change
Expand Up @@ -304,7 +304,7 @@ public:
}
}

template <class... _IndexTypes, size_t... _Seq>
template <size_t... _Seq, class... _IndexTypes>
_NODISCARD constexpr bool _Contains_multidimensional_index(
index_sequence<_Seq...>, _IndexTypes... _Indices) const noexcept {
_STL_INTERNAL_STATIC_ASSERT((same_as<_IndexTypes, index_type> && ...));
Expand All @@ -321,7 +321,7 @@ inline constexpr size_t _Repeat_dynamic_extent = dynamic_extent;

template <class... _Integrals>
requires (is_convertible_v<_Integrals, size_t> && ...)
extents(_Integrals...) -> extents<size_t, _Repeat_dynamic_extent<_Integrals>...>;
explicit extents(_Integrals...) -> extents<size_t, _Repeat_dynamic_extent<_Integrals>...>;

template <class _IndexType, class _Indices>
struct _Dextents_impl;
Expand Down Expand Up @@ -532,7 +532,7 @@ public:
template <class _OtherExtents>
requires is_constructible_v<extents_type, _OtherExtents>
constexpr explicit(extents_type::rank() > 0)
mapping(const layout_stride::template mapping<_OtherExtents>& _Other) noexcept // strengthened
mapping(const layout_stride::mapping<_OtherExtents>& _Other) noexcept // strengthened
: _Base(_Other.extents()) {
#if _CONTAINER_DEBUG_LEVEL > 0
if constexpr (extents_type::rank() > 0) {
Expand Down Expand Up @@ -684,8 +684,7 @@ public:

template <class _OtherExtents>
requires is_constructible_v<extents_type, _OtherExtents>
constexpr explicit(extents_type::rank() > 0)
mapping(const layout_stride::template mapping<_OtherExtents>& _Other) noexcept
constexpr explicit(extents_type::rank() > 0) mapping(const layout_stride::mapping<_OtherExtents>& _Other) noexcept
: _Base(_Other.extents()) {
#if _CONTAINER_DEBUG_LEVEL > 0
if constexpr (extents_type::rank() > 0) {
Expand Down Expand Up @@ -1045,13 +1044,13 @@ struct default_accessor {
requires is_convertible_v<_OtherElementType (*)[], element_type (*)[]>
constexpr default_accessor(default_accessor<_OtherElementType>) noexcept {}

_NODISCARD constexpr data_handle_type offset(data_handle_type _Ptr, size_t _Idx) const noexcept {
return _Ptr + _Idx;
}

_NODISCARD constexpr reference access(data_handle_type _Ptr, size_t _Idx) const noexcept {
return _Ptr[_Idx];
}

_NODISCARD constexpr data_handle_type offset(data_handle_type _Ptr, size_t _Idx) const noexcept {
return _Ptr + _Idx;
}
};

template <class _LayoutPolicy, class _Extents>
Expand Down Expand Up @@ -1200,7 +1199,7 @@ public:
_Ptr(_STD move(_Ptr_)) {}

template <class _OtherIndexType, size_t _Size>
requires is_convertible_v<_OtherIndexType, index_type>
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>
&& (_Size == rank() || _Size == rank_dynamic())
&& is_constructible_v<mapping_type, extents_type> && is_default_constructible_v<accessor_type>
Expand Down Expand Up @@ -1277,32 +1276,45 @@ public:
noexcept(noexcept(_Access_impl(static_cast<index_type>(_STD move(_Indices))...))) /* strengthened */ {
return _Access_impl(static_cast<index_type>(_STD move(_Indices))...);
}
#endif // __cpp_multidimensional_subscript

private:
template <class _OtherIndexType, size_t... _Seq>
_NODISCARD constexpr reference _Multidimensional_subscript(span<_OtherIndexType, rank()> _Indices,
index_sequence<_Seq...>) const noexcept(noexcept(operator[](_STD as_const(_Indices[_Seq])...))) {
return operator[](_STD as_const(_Indices[_Seq])...);
}
#else // ^^^ defined(__cpp_multidimensional_subscript) / !defined(__cpp_multidimensional_subscript) vvv
private:
template <class... _OtherIndexTypes>
_NODISCARD constexpr reference _Multidimensional_access(_OtherIndexTypes... _Indices) const
noexcept(noexcept(_Access_impl(static_cast<index_type>(_STD move(_Indices))...))) {
return _Access_impl(static_cast<index_type>(_STD move(_Indices))...);
}

template <class _OtherIndexType, size_t... _Seq>
_NODISCARD constexpr reference _Multidimensional_subscript(span<_OtherIndexType, rank()> _Indices,
index_sequence<_Seq...>) const noexcept(noexcept(_Multidimensional_access(_STD as_const(_Indices[_Seq])...))) {
return _Multidimensional_access(_STD as_const(_Indices[_Seq])...);
}
#endif // ^^^ !defined(__cpp_multidimensional_subscript) ^^^

public:
template <class _OtherIndexType>
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>
_NODISCARD constexpr reference operator[](span<_OtherIndexType, rank()> _Indices) const {
return [&]<size_t... _Seq>(index_sequence<_Seq...>) -> reference {
#ifdef __cpp_multidimensional_subscript // TRANSITION, P2128R6
return operator[](_STD as_const(_Indices[_Seq])...);
#else // ^^^ defined(__cpp_multidimensional_subscript) / !defined(__cpp_multidimensional_subscript) vvv
return _Multidimensional_access(_STD as_const(_Indices[_Seq])...);
#endif // ^^^ !defined(__cpp_multidimensional_subscript) ^^^
}(make_index_sequence<rank()>{});
_NODISCARD constexpr reference operator[](span<_OtherIndexType, rank()> _Indices) const
noexcept(noexcept(_Multidimensional_subscript(_Indices, make_index_sequence<rank()>{}))) /* strengthened */
{
return _Multidimensional_subscript(_Indices, make_index_sequence<rank()>{});
}

template <class _OtherIndexType>
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>
_NODISCARD constexpr reference operator[](const array<_OtherIndexType, rank()>& _Indices) const {
return [&]<size_t... _Seq>(index_sequence<_Seq...>) -> reference {
#ifdef __cpp_multidimensional_subscript // TRANSITION, P2128R6
return operator[](_Indices[_Seq]...);
#else // ^^^ defined(__cpp_multidimensional_subscript) / !defined(__cpp_multidimensional_subscript) vvv
return _Multidimensional_access(_Indices[_Seq]...);
#endif // ^^^ !defined(__cpp_multidimensional_subscript) ^^^
}(make_index_sequence<rank()>{});
_NODISCARD constexpr reference operator[](const array<_OtherIndexType, rank()>& _Indices) const noexcept(
noexcept(_Multidimensional_subscript(span{_Indices}, make_index_sequence<rank()>{}))) /* strengthened */
{
return _Multidimensional_subscript(span{_Indices}, make_index_sequence<rank()>{});
}

_NODISCARD constexpr size_type size() const noexcept {
Expand Down Expand Up @@ -1359,19 +1371,19 @@ public:
return this->_Acc;
}

_NODISCARD static constexpr bool is_always_unique() noexcept(
noexcept(mapping_type::is_always_unique())) /* strengthened */ {
return mapping_type::is_always_unique();
_NODISCARD static constexpr bool is_always_unique() noexcept /* strengthened */ {
constexpr bool _Result = mapping_type::is_always_unique();
return _Result;
}

_NODISCARD static constexpr bool is_always_exhaustive() noexcept(
noexcept(mapping_type::is_always_exhaustive())) /* strengthened */ {
return mapping_type::is_always_exhaustive();
_NODISCARD static constexpr bool is_always_exhaustive() noexcept /* strengthened */ {
constexpr bool _Result = mapping_type::is_always_exhaustive();
return _Result;
}

_NODISCARD static constexpr bool is_always_strided() noexcept(
noexcept(mapping_type::is_always_strided())) /* strengthened */ {
return mapping_type::is_always_strided();
_NODISCARD static constexpr bool is_always_strided() noexcept /* strengthened */ {
constexpr bool _Result = mapping_type::is_always_strided();
return _Result;
}

_NODISCARD constexpr bool is_unique() const noexcept(noexcept(this->_Map.is_unique())) /* strengthened */ {
Expand All @@ -1392,16 +1404,9 @@ public:
}

private:
#ifndef __cpp_multidimensional_subscript // TRANSITION, P2128R6
template <class... _OtherIndexTypes>
_NODISCARD constexpr reference _Multidimensional_access(_OtherIndexTypes... _Indices) const {
return _Access_impl(static_cast<index_type>(_STD move(_Indices))...);
}
#endif // ^^^ !defined(__cpp_multidimensional_subscript) ^^^

template <class... _OtherIndexTypes>
_NODISCARD constexpr reference _Access_impl(_OtherIndexTypes... _Indices) const
noexcept(noexcept(this->_Acc.access(_Ptr, static_cast<size_t>(this->_Map(_Indices...))))) /* strengthened */ {
noexcept(noexcept(this->_Acc.access(_Ptr, static_cast<size_t>(this->_Map(_Indices...))))) {
_STL_INTERNAL_STATIC_ASSERT((same_as<_OtherIndexTypes, index_type> && ...));
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Map.extents()._Contains_multidimensional_index(make_index_sequence<rank()>{}, _Indices...),
Expand Down