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///////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
//
// This code is licensed under the MIT License (MIT).
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef GSL_SPAN_H
#define GSL_SPAN_H
#include <gsl/assert> // for Expects
#include <gsl/byte> // for byte
#include <gsl/util> // for narrow_cast
#include <array> // for array
#include <cstddef> // for ptrdiff_t, size_t, nullptr_t
#include <gsl/span_ext> // for span specialization of gsl::at and other span-related extensions
#include <iterator> // for reverse_iterator, distance, random_access_...
#include <type_traits> // for enable_if_t, declval, is_convertible, inte...
#if defined(_MSC_VER) && !defined(__clang__)
#pragma warning(push)
// turn off some warnings that are noisy about our Expects statements
#pragma warning(disable : 4127) // conditional expression is constant
#pragma warning( \
disable : 4146) // unary minus operator applied to unsigned type, result still unsigned
#pragma warning(disable : 4702) // unreachable code
// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
#pragma warning(disable : 26495) // uninitalized member when constructor calls constructor
#pragma warning(disable : 26446) // parser bug does not allow attributes on some templates
#endif // _MSC_VER
// See if we have enough C++17 power to use a static constexpr data member
// without needing an out-of-line definition
#if !(defined(__cplusplus) && (__cplusplus >= 201703L))
#define GSL_USE_STATIC_CONSTEXPR_WORKAROUND
#endif // !(defined(__cplusplus) && (__cplusplus >= 201703L))
// GCC 7 does not like the signed unsigned missmatch (size_t ptrdiff_t)
// While there is a conversion from signed to unsigned, it happens at
// compiletime, so the compiler wouldn't have to warn indiscriminately, but
// could check if the source value actually doesn't fit into the target type
// and only warn in those cases.
#if defined(__GNUC__) && __GNUC__ > 6
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsign-conversion"
#endif
namespace gsl
{
// implementation details
namespace details
{
template <class T>
struct is_span_oracle : std::false_type
{
};
template <class ElementType, std::size_t Extent>
struct is_span_oracle<gsl::span<ElementType, Extent>> : std::true_type
{
};
template <class T>
struct is_span : public is_span_oracle<std::remove_cv_t<T>>
{
};
template <class T>
struct is_std_array_oracle : std::false_type
{
};
template <class ElementType, std::size_t Extent>
struct is_std_array_oracle<std::array<ElementType, Extent>> : std::true_type
{
};
template <class T>
struct is_std_array : is_std_array_oracle<std::remove_cv_t<T>>
{
};
template <std::size_t From, std::size_t To>
struct is_allowed_extent_conversion
: std::integral_constant<bool, From == To || To == dynamic_extent>
{
};
template <class From, class To>
struct is_allowed_element_type_conversion
: std::integral_constant<bool, std::is_convertible<From (*)[], To (*)[]>::value>
{
};
template <class Type>
class span_iterator
{
public:
using iterator_category = std::random_access_iterator_tag;
using value_type = std::remove_cv_t<Type>;
using difference_type = std::ptrdiff_t;
using pointer = Type*;
using reference = Type&;
#ifdef _MSC_VER
using _Unchecked_type = pointer;
#endif // _MSC_VER
constexpr span_iterator() = default;
constexpr span_iterator(pointer begin, pointer end, pointer current)
: begin_(begin), end_(end), current_(current)
{}
constexpr operator span_iterator<const Type>() const noexcept
{
return {begin_, end_, current_};
}
constexpr reference operator*() const noexcept
{
Expects(begin_ && end_);
Expects(begin_ <= current_ && current_ < end_);
return *current_;
}
constexpr pointer operator->() const noexcept
{
Expects(begin_ && end_);
Expects(begin_ <= current_ && current_ < end_);
return current_;
}
constexpr span_iterator& operator++() noexcept
{
Expects(begin_ && current_ && end_);
Expects(current_ < end_);
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
++current_;
return *this;
}
constexpr span_iterator operator++(int) noexcept
{
span_iterator ret = *this;
++*this;
return ret;
}
constexpr span_iterator& operator--() noexcept
{
Expects(begin_ && end_);
Expects(begin_ < current_);
--current_;
return *this;
}
constexpr span_iterator operator--(int) noexcept
{
span_iterator ret = *this;
--*this;
return ret;
}
constexpr span_iterator& operator+=(const difference_type n) noexcept
{
if (n != 0) Expects(begin_ && current_ && end_);
if (n > 0) Expects(end_ - current_ >= n);
if (n < 0) Expects(current_ - begin_ >= -n);
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
current_ += n;
return *this;
}
constexpr span_iterator operator+(const difference_type n) const noexcept
{
span_iterator ret = *this;
ret += n;
return ret;
}
friend constexpr span_iterator operator+(const difference_type n,
const span_iterator& rhs) noexcept
{
return rhs + n;
}
constexpr span_iterator& operator-=(const difference_type n) noexcept
{
if (n != 0) Expects(begin_ && current_ && end_);
if (n > 0) Expects(current_ - begin_ >= n);
if (n < 0) Expects(end_ - current_ >= -n);
current_ -= n;
return *this;
}
constexpr span_iterator operator-(const difference_type n) const noexcept
{
span_iterator ret = *this;
ret -= n;
return ret;
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr difference_type operator-(const span_iterator<Type2>& rhs) const noexcept
{
Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
return current_ - rhs.current_;
}
constexpr reference operator[](const difference_type n) const noexcept
{
return *(*this + n);
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator==(const span_iterator<Type2>& rhs) const noexcept
{
Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
return current_ == rhs.current_;
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator!=(const span_iterator<Type2>& rhs) const noexcept
{
return !(*this == rhs);
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator<(const span_iterator<Type2>& rhs) const noexcept
{
Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
return current_ < rhs.current_;
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator>(const span_iterator<Type2>& rhs) const noexcept
{
return rhs < *this;
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator<=(const span_iterator<Type2>& rhs) const noexcept
{
return !(rhs < *this);
}
template <
class Type2,
std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
constexpr bool operator>=(const span_iterator<Type2>& rhs) const noexcept
{
return !(*this < rhs);
}
#ifdef _MSC_VER
// MSVC++ iterator debugging support; allows STL algorithms in 15.8+
// to unwrap span_iterator to a pointer type after a range check in STL
// algorithm calls
friend constexpr void _Verify_range(span_iterator lhs, span_iterator rhs) noexcept
{ // test that [lhs, rhs) forms a valid range inside an STL algorithm
Expects(lhs.begin_ == rhs.begin_ // range spans have to match
&& lhs.end_ == rhs.end_ &&
lhs.current_ <= rhs.current_); // range must not be transposed
}
constexpr void _Verify_offset(const difference_type n) const noexcept
{ // test that *this + n is within the range of this call
if (n != 0) Expects(begin_ && current_ && end_);
if (n > 0) Expects(end_ - current_ >= n);
if (n < 0) Expects(current_ - begin_ >= -n);
}
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
constexpr pointer _Unwrapped() const noexcept
{ // after seeking *this to a high water mark, or using one of the
// _Verify_xxx functions above, unwrap this span_iterator to a raw
// pointer
return current_;
}
// Tell the STL that span_iterator should not be unwrapped if it can't
// validate in advance, even in release / optimized builds:
#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
static constexpr const bool _Unwrap_when_unverified = false;
#else
static constexpr bool _Unwrap_when_unverified = false;
#endif
// clang-format off
GSL_SUPPRESS(con.3) // NO-FORMAT: attribute // TODO: false positive
// clang-format on
constexpr void _Seek_to(const pointer p) noexcept
{ // adjust the position of *this to previously verified location p
// after _Unwrapped
current_ = p;
}
#endif
pointer begin_ = nullptr;
pointer end_ = nullptr;
pointer current_ = nullptr;
};
template <std::size_t Ext>
class extent_type
{
public:
using size_type = std::size_t;
constexpr extent_type() noexcept = default;
constexpr explicit extent_type(extent_type<dynamic_extent>);
constexpr explicit extent_type(size_type size) { Expects(size == Ext); }
constexpr size_type size() const noexcept { return Ext; }
private:
#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
static constexpr const size_type size_ = Ext; // static size equal to Ext
#else
static constexpr size_type size_ = Ext; // static size equal to Ext
#endif
};
template <>
class extent_type<dynamic_extent>
{
public:
using size_type = std::size_t;
template <size_type Other>
constexpr explicit extent_type(extent_type<Other> ext) : size_(ext.size())
{}
constexpr explicit extent_type(size_type size) : size_(size)
{
Expects(size != dynamic_extent);
}
constexpr size_type size() const noexcept { return size_; }
private:
size_type size_;
};
template <std::size_t Ext>
constexpr extent_type<Ext>::extent_type(extent_type<dynamic_extent> ext)
{
Expects(ext.size() == Ext);
}
template <class ElementType, std::size_t Extent, std::size_t Offset, std::size_t Count>
struct calculate_subspan_type
{
using type = span<ElementType, Count != dynamic_extent
? Count
: (Extent != dynamic_extent ? Extent - Offset : Extent)>;
};
} // namespace details
// [span], class template span
template <class ElementType, std::size_t Extent>
class span
{
public:
// constants and types
using element_type = ElementType;
using value_type = std::remove_cv_t<ElementType>;
using size_type = std::size_t;
using pointer = element_type*;
using const_pointer = const element_type*;
using reference = element_type&;
using const_reference = const element_type&;
using difference_type = std::ptrdiff_t;
using iterator = details::span_iterator<ElementType>;
using reverse_iterator = std::reverse_iterator<iterator>;
#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
static constexpr const size_type extent{Extent};
#else
static constexpr size_type extent{Extent};
#endif
// [span.cons], span constructors, copy, assignment, and destructor
template <bool Dependent = false,
// "Dependent" is needed to make "std::enable_if_t<Dependent || Extent == 0 || Extent
// == dynamic_extent>" SFINAE, since "std::enable_if_t<Extent == 0 || Extent ==
// dynamic_extent>" is ill-formed when Extent is greater than 0.
class = std::enable_if_t<(Dependent ||
details::is_allowed_extent_conversion<0, Extent>::value)>>
constexpr span() noexcept : storage_(nullptr, details::extent_type<0>())
{}
template <std::size_t MyExtent = Extent, std::enable_if_t<MyExtent != dynamic_extent, int> = 0>
constexpr explicit span(pointer ptr, size_type count) noexcept : storage_(ptr, count)
{
Expects(count == Extent);
}
template <std::size_t MyExtent = Extent, std::enable_if_t<MyExtent == dynamic_extent, int> = 0>
constexpr span(pointer ptr, size_type count) noexcept : storage_(ptr, count)
{}
template <std::size_t MyExtent = Extent, std::enable_if_t<MyExtent != dynamic_extent, int> = 0>
constexpr explicit span(pointer firstElem, pointer lastElem) noexcept
: storage_(firstElem, narrow_cast<std::size_t>(lastElem - firstElem))
{
Expects(lastElem - firstElem == static_cast<difference_type>(Extent));
}
template <std::size_t MyExtent = Extent, std::enable_if_t<MyExtent == dynamic_extent, int> = 0>
constexpr span(pointer firstElem, pointer lastElem) noexcept
: storage_(firstElem, narrow_cast<std::size_t>(lastElem - firstElem))
{}
template <std::size_t N,
std::enable_if_t<details::is_allowed_extent_conversion<N, Extent>::value, int> = 0>
constexpr span(element_type (&arr)[N]) noexcept
: storage_(KnownNotNull{arr}, details::extent_type<N>())
{}
template <
class T, std::size_t N,
std::enable_if_t<(details::is_allowed_extent_conversion<N, Extent>::value &&
details::is_allowed_element_type_conversion<T, element_type>::value),
int> = 0>
constexpr span(std::array<T, N>& arr) noexcept
: storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
{}
template <class T, std::size_t N,
std::enable_if_t<
(details::is_allowed_extent_conversion<N, Extent>::value &&
details::is_allowed_element_type_conversion<const T, element_type>::value),
int> = 0>
constexpr span(const std::array<T, N>& arr) noexcept
: storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
{}
// NB: the SFINAE on these constructors uses .data() as an incomplete/imperfect proxy for the
// requirement on Container to be a contiguous sequence container.
template <std::size_t MyExtent = Extent, class Container,
std::enable_if_t<
MyExtent != dynamic_extent && !details::is_span<Container>::value &&
!details::is_std_array<Container>::value &&
std::is_pointer<decltype(std::declval<Container&>().data())>::value &&
std::is_convertible<
std::remove_pointer_t<decltype(std::declval<Container&>().data())> (*)[],
element_type (*)[]>::value,
int> = 0>
constexpr explicit span(Container& cont) noexcept : span(cont.data(), cont.size())
{}
template <std::size_t MyExtent = Extent, class Container,
std::enable_if_t<
MyExtent == dynamic_extent && !details::is_span<Container>::value &&
!details::is_std_array<Container>::value &&
std::is_pointer<decltype(std::declval<Container&>().data())>::value &&
std::is_convertible<
std::remove_pointer_t<decltype(std::declval<Container&>().data())> (*)[],
element_type (*)[]>::value,
int> = 0>
constexpr span(Container& cont) noexcept : span(cont.data(), cont.size())
{}
template <
std::size_t MyExtent = Extent, class Container,
std::enable_if_t<
MyExtent != dynamic_extent && std::is_const<element_type>::value &&
!details::is_span<Container>::value && !details::is_std_array<Container>::value &&
std::is_pointer<decltype(std::declval<const Container&>().data())>::value &&
std::is_convertible<
std::remove_pointer_t<decltype(std::declval<const Container&>().data())> (*)[],
element_type (*)[]>::value,
int> = 0>
constexpr explicit span(const Container& cont) noexcept : span(cont.data(), cont.size())
{}
template <
std::size_t MyExtent = Extent, class Container,
std::enable_if_t<
MyExtent == dynamic_extent && std::is_const<element_type>::value &&
!details::is_span<Container>::value && !details::is_std_array<Container>::value &&
std::is_pointer<decltype(std::declval<const Container&>().data())>::value &&
std::is_convertible<
std::remove_pointer_t<decltype(std::declval<const Container&>().data())> (*)[],
element_type (*)[]>::value,
int> = 0>
constexpr span(const Container& cont) noexcept : span(cont.data(), cont.size())
{}
constexpr span(const span& other) noexcept = default;
template <class OtherElementType, std::size_t OtherExtent, std::size_t MyExtent = Extent,
std::enable_if_t<(MyExtent == dynamic_extent || MyExtent == OtherExtent) &&
details::is_allowed_element_type_conversion<OtherElementType,
element_type>::value,
int> = 0>
constexpr span(const span<OtherElementType, OtherExtent>& other) noexcept
: storage_(other.data(), details::extent_type<OtherExtent>(other.size()))
{}
template <class OtherElementType, std::size_t OtherExtent, std::size_t MyExtent = Extent,
std::enable_if_t<MyExtent != dynamic_extent && OtherExtent == dynamic_extent &&
details::is_allowed_element_type_conversion<OtherElementType,
element_type>::value,
int> = 0>
constexpr explicit span(const span<OtherElementType, OtherExtent>& other) noexcept
: storage_(other.data(), details::extent_type<OtherExtent>(other.size()))
{}
~span() noexcept = default;
constexpr span& operator=(const span& other) noexcept = default;
// [span.sub], span subviews
template <std::size_t Count>
constexpr span<element_type, Count> first() const noexcept
{
Expects(Count <= size());
return span<element_type, Count>{data(), Count};
}
template <std::size_t Count>
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
constexpr span<element_type, Count> last() const noexcept
{
Expects(Count <= size());
return span<element_type, Count>{data() + (size() - Count), Count};
}
template <std::size_t Offset, std::size_t Count = dynamic_extent>
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
constexpr auto subspan() const noexcept ->
typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type
{
Expects((size() >= Offset) && (Count == dynamic_extent || (Count <= size() - Offset)));
using type =
typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type;
return type{data() + Offset, Count == dynamic_extent ? size() - Offset : Count};
}
constexpr span<element_type, dynamic_extent> first(size_type count) const noexcept
{
Expects(count <= size());
return {data(), count};
}
constexpr span<element_type, dynamic_extent> last(size_type count) const noexcept
{
Expects(count <= size());
return make_subspan(size() - count, dynamic_extent, subspan_selector<Extent>{});
}
constexpr span<element_type, dynamic_extent>
subspan(size_type offset, size_type count = dynamic_extent) const noexcept
{
return make_subspan(offset, count, subspan_selector<Extent>{});
}
// [span.obs], span observers
constexpr size_type size() const noexcept { return storage_.size(); }
constexpr size_type size_bytes() const noexcept
{
Expects(size() < dynamic_extent / sizeof(element_type));
return size() * sizeof(element_type);
}
constexpr bool empty() const noexcept { return size() == 0; }
// [span.elem], span element access
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
constexpr reference operator[](size_type idx) const noexcept
{
Expects(idx < size());
return data()[idx];
}
constexpr reference front() const noexcept
{
Expects(size() > 0);
return data()[0];
}
constexpr reference back() const noexcept
{
Expects(size() > 0);
return data()[size() - 1];
}
constexpr pointer data() const noexcept { return storage_.data(); }
// [span.iter], span iterator support
constexpr iterator begin() const noexcept
{
const auto data = storage_.data();
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
return {data, data + size(), data};
}
constexpr iterator end() const noexcept
{
const auto data = storage_.data();
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
const auto endData = data + storage_.size();
return {data, endData, endData};
}
constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator{end()}; }
constexpr reverse_iterator rend() const noexcept { return reverse_iterator{begin()}; }
#ifdef _MSC_VER
// Tell MSVC how to unwrap spans in range-based-for
constexpr pointer _Unchecked_begin() const noexcept { return data(); }
constexpr pointer _Unchecked_end() const noexcept
{
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
return data() + size();
}
#endif // _MSC_VER
private:
// Needed to remove unnecessary null check in subspans
struct KnownNotNull
{
pointer p;
};
// this implementation detail class lets us take advantage of the
// empty base class optimization to pay for only storage of a single
// pointer in the case of fixed-size spans
template <class ExtentType>
class storage_type : public ExtentType
{
public:
// KnownNotNull parameter is needed to remove unnecessary null check
// in subspans and constructors from arrays
template <class OtherExtentType>
constexpr storage_type(KnownNotNull data, OtherExtentType ext)
: ExtentType(ext), data_(data.p)
{
Expects(ExtentType::size() != dynamic_extent);
}
template <class OtherExtentType>
constexpr storage_type(pointer data, OtherExtentType ext) : ExtentType(ext), data_(data)
{
Expects(ExtentType::size() != dynamic_extent);
Expects(data || ExtentType::size() == 0);
}
constexpr pointer data() const noexcept { return data_; }
private:
pointer data_;
};
storage_type<details::extent_type<Extent>> storage_;
// The rest is needed to remove unnecessary null check
// in subspans and constructors from arrays
constexpr span(KnownNotNull ptr, size_type count) noexcept : storage_(ptr, count) {}
template <std::size_t CallerExtent>
class subspan_selector
{
};
template <std::size_t CallerExtent>
constexpr span<element_type, dynamic_extent>
make_subspan(size_type offset, size_type count, subspan_selector<CallerExtent>) const noexcept
{
const span<element_type, dynamic_extent> tmp(*this);
return tmp.subspan(offset, count);
}
// clang-format off
GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
// clang-format on
constexpr span<element_type, dynamic_extent>
make_subspan(size_type offset, size_type count, subspan_selector<dynamic_extent>) const noexcept
{
Expects(size() >= offset);
if (count == dynamic_extent) { return {KnownNotNull{data() + offset}, size() - offset}; }
Expects(size() - offset >= count);
return {KnownNotNull{data() + offset}, count};
}
};
#if (defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L))
// Deduction Guides
template <class Type, std::size_t Extent>
span(Type (&)[Extent]) -> span<Type, Extent>;
template <class Type, std::size_t Size>
span(std::array<Type, Size>&) -> span<Type, Size>;
template <class Type, std::size_t Size>
span(const std::array<Type, Size>&) -> span<const Type, Size>;
template <class Container,
class Element = std::remove_pointer_t<decltype(std::declval<Container&>().data())>>
span(Container&) -> span<Element>;
template <class Container,
class Element = std::remove_pointer_t<decltype(std::declval<const Container&>().data())>>
span(const Container&) -> span<Element>;
#endif // ( defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L) )
#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
template <class ElementType, std::size_t Extent>
constexpr const typename span<ElementType, Extent>::size_type span<ElementType, Extent>::extent;
#endif
namespace details
{
// if we only supported compilers with good constexpr support then
// this pair of classes could collapse down to a constexpr function
// we should use a narrow_cast<> to go to std::size_t, but older compilers may not see it as
// constexpr
// and so will fail compilation of the template
template <class ElementType, std::size_t Extent>
struct calculate_byte_size : std::integral_constant<std::size_t, sizeof(ElementType) * Extent>
{
static_assert(Extent < dynamic_extent / sizeof(ElementType), "Size is too big.");
};
template <class ElementType>
struct calculate_byte_size<ElementType, dynamic_extent>
: std::integral_constant<std::size_t, dynamic_extent>
{
};
} // namespace details
// [span.objectrep], views of object representation
template <class ElementType, std::size_t Extent>
span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
as_bytes(span<ElementType, Extent> s) noexcept
{
using type = span<const byte, details::calculate_byte_size<ElementType, Extent>::value>;
// clang-format off
GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
// clang-format on
return type{reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
}
template <class ElementType, std::size_t Extent,
std::enable_if_t<!std::is_const<ElementType>::value, int> = 0>
span<byte, details::calculate_byte_size<ElementType, Extent>::value>
as_writable_bytes(span<ElementType, Extent> s) noexcept
{
using type = span<byte, details::calculate_byte_size<ElementType, Extent>::value>;
// clang-format off
GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
// clang-format on
return type{reinterpret_cast<byte*>(s.data()), s.size_bytes()};
}
} // namespace gsl
#if defined(_MSC_VER) && !defined(__clang__)
#pragma warning(pop)
#endif // _MSC_VER
#if defined(__GNUC__) && __GNUC__ > 6
#pragma GCC diagnostic pop
#endif // __GNUC__ > 6
#endif // GSL_SPAN_H
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